AbuKhader, S. (2000). Micro evaluation of urban traffic noise for Gothenburg – the potential existence of quiet sides in dwellings. Göteborg, Sweden: Chalmers University of Technology, Applied Acoustics, Report E 00-01. (MSc Thesis)Axelsson, Ö. (2007). Individual differences in preferences to photographs. Psychology of Aesthetics, Creativity, and the Arts, 2007, 1(2), 61-72.
Individual differences in preferences to photographs were explored based on an alternative framework. This framework predicts that the primary difference between individuals in this respect is their ability to process photographic information, which in turn influences their preferences. Chiefly, people with well-developed schemes in photography (e.g., photo professionals) should have a higher ability to process photographic information than people with less developed schemes (e.g., psychology students). Consequently, people with well-developed schemes in photography should prefer photographs that are relatively more demanding to process. Ten psychology students and 5 photo professionals assessed 32 photographs on six general concepts: Preference, Hedonic Tone, Expressiveness, Familiarity, Uncertainty, and Dynamics. As predicted, photo professionals had a higher ability to process photographic information and preferred photographs that were relatively uncertain and unfamiliar. These results are in concordance with previous research and give strong support to the utility of the present framework in experimental aesthetics.
Axelsson, Ö., Berglund, B., & Nilsson, M.E. (2003). Towards green labeling of soundscapes in residential areas. In G. Brambilla, C. Ianbiello & L. Maffei (Eds.), EURONOISE 2003. Rome, Italy: Italian Association of Acoustics (AIA). (Available on CD)
‘Green’ labeling of soundscapes would require a metric ‘diagnostic’ system. Since great differences exist among soundscapes in various environmental contexts (e.g., urban or rural), the selected context was delimited to road-traffic noise exposed residential areas. A large database of 30-s binaural recordings from noise-exposed and noise-shielded sides of buildings provided 14 representative soundscape excerpts. Twenty-one participants scaled these with regard to perceived similarity (196 pairs) and to four perceptual-emotional attributes. Multidimensional scaling of individual (dis)similarity matrices gave three ‘perceptual’ dimensions (INDSCAL): (1) softness–loudness, (2) eventfulness–monotonousness, and (3) foreground–back-ground. To aid further labeling of individual soundscapes, four attribute scales were introduced as vectors in the INDSCAL solution (annoying, appealing, boring, and interesting). For the noise-exposed side, three loud and monotonous soundscapes were found to be more annoying and boring than the ones that were eventful (still background) or contained bird song (foreground). The latter were also labeled more interesting. For the noise-shielded side, six soft and monotonous and three bird-song soundscapes were found to be approximately equally appealing and interesting. The present empirically determined tentative ‘diagnostic’ system constitutes a good starting point for classification and ‘green’ labeling of soundscapes in residential areas.
Axelsson, Ö., Berglund, B., & Nilsson, M.E. (2005). Soundscape assessment. Journal of the Acoustical Society of America, 2005, 117(4), Pt. 2, 2591-2592
In order to improve the quality of the soundscape it is necessary to know its descriptive and evaluative properties, and the relationships between these properties. This was explored in a listening experiment with 100 participants (48 women, 52 men; mean age 25,6 years). Each participant scaled 5 out of 50 soundscapes with regard to 116 single verbal attributes, using a visual analogue scale of agreeableness. In addition, acoustical properties of the soundscapes were assessed. A principal component analysis identified two major evaluative components, labeled Hedonic Tone and Eventfulness. Furthermore it was found the mere presence of common sound sources, regardless of sound level, correlated significantly with these evaluative components. Technological sounds (e.g., traffic noise) were negatively associated with both Hedonic Tone and Eventfulness, while a positive association was found between Hedonic Tone and sounds of nature (e.g., bird song), and a positive association was found between Eventfulness and human sounds (e.g., human voices). These relationships lead to the hypothesis that introduction of nature and human sounds, in combination with the reduction of technological sounds may improve the quality of soundscapes considerably.
Berglund, B. (2002). Master scaling and its applications. In J.A. Da Silva, E.H. Matsushima & N. P. Ribeiro-Filho (Eds.), Fechner Day 2002. Rio de Janeiro, Brazil: International Society for Psychophysics, pp. 40-45
Master scaling is a method by which individual perceptual scales may be calibrated and compared on a master scale. For this purpose references are scaled jointly with the target events. It is intended for one-point measurements by different perceivers at different occasions. Two types of applications are empirically demonstrated. Three patients’ unique neuropathic pain areas (upper arm, hand or stomach) were made comparable by master scaling the perceived intensity of warmth in these areas with the aid of 32 thenar temperature references. In four residential areas, 106 residents’ unique outdoor soundscapes were made comparable by master scaling loudness in the context of seven pink noise references. In master scaling, each perceiver’s scaling behavior is assessed for the common references which also constitute the context for the scaling task, the target(s). The reference functions are common to all participants and may be used for testing scaling ability in the study environment.
Berglund, B. (2006). From the WHO Guidelines for community noise to healthy soundscapes. Proceedings of the Institute of Acoustics, 2006, 28, Pt 7, pp. 1-9.
Community noise destroys environments which otherwise could have been quiet and restorative, such as court yards, gardens, parks and other green urban and suburban areas. Wide gaps exist between current sound levels and those adopted in the WHO guidelines for community noise. A wide gap also exists between current long-term goals and the goals that would constitute good sound environments. Thus far, community-noise pollution has in principle been viewed as a pure engineering problem, not a health problem. The objective of the WHO guidelines and the EC environmental noise directive is to protect people from the harmful effects of noise. Both also recommend education and information as noise management measures, besides the legal and engineering measures. However, in practice there is an inbuilt conflict which abuses the health goals. WHO guideline values are based on different critical health effects which are linked to the “all-noise” immission in specific environments and sensitive time periods for sensitive groups during specific activities. In contrast, noise maps and remedial actions against noise are concerned with sound levels of a specific noise source. It is not enough to protect and prevent against the predominating noise. The way forward is to promote and support the development of healthy soundscapes. One goal of long-term city planning must be to provide soundscapes supportive to health.
Berglund, B. (2006). Towards supportive residential soundscapes, indoors and outdoors. In Abstract Guide of the 26th International Congress in Applied Psychology. Athens: International Association of Applied Psychology, 2006, Abstract S54.1.
Health-supportive soundscapes can best be accomplished if noise pollution is abated in harmony with creative city planning. In order to design better soundscapes in residential areas, outdoors and indoors, we have to know what sounds are discerned and what kinds of soundscapes are adverse (e.g., disturbance) or positive (e.g., tranquillity). Today regulation is limited to energetic time-averages for specific traffic (road, rail & air) and industrial noise. No information is conveyed on sound components, on structure of their composite, or the acoustic soundscape. Also the WHO health-based guideline values are grounded in longterm equivalent continuous sound levels. Such averages, based on the amount of traffic and short-term soundlevels, allow for worst-noise component approximations, but do not characterize the soundscape per se. Alternatively, a strategy is here proposed which aims at delivering prognostic design tools for perceived soundscapes. Recent research results will be presented from our residential soundscape database. It includes a dualistic soundscape similarity approach for differentiating various perceptual and acoustic qualitative aspects of soundscapes as well as a diagnostic system for soundscape certification, which builds on a neural network classifier. Both tools may be used in soundscape design and mitigation psychophysics.
Berglund, B. (2007). Noise and our Children – Their Education and Protection. In: Public Pressure–An Effective Force. Poughkeepsie, NY: Noise Control Foundation, 2007, pp. 8-10.
Children and adults are exposed to the same kinds of noise, that is, from road, rail and air traffic, industries, construction work, discos, music and sports events, playgrounds, fireworks and other impulse noise. Common noise indoors is sound from children’s own play, toys, music and playing devices as well as ventilation systems. Together these sounds form their ”soundscape”, which exists not only indoors but also outdoors in places such as balconies, yards, playgrounds, and on the way to and from school. In Sweden, 0.2-0.3 % of newly born are hearing impaired whereas the estimate has grown to 3 to 4% among the 12-year old girls and boys, respectively. After listening to loud music or other loud sound, 20% of the 12-year olds experience ringing, squeaking, howling or buzzing in their ears; about half of these children report that their hearing becomes worse after noise exposure. After long-term aircraft noise exposure, school children are found to perform worse in proofreading, completing jigsaw puzzles, and reading comprehension as well as to have poorer memory, motivation and language acquisition. Bilinguals are especially vulnerable to noise. The longer and stronger the exposure, the greater the harmful effects seem to be. In UK and the Netherlands, 5 dBA higher sound-level exposures of school buildings have been shown to correspond to a 2-month or 1-month loss, respectively, in the children’s learning.
Berglund, B., Axelsson, Ö., & Nilsson, M. E. (2005). The soundscape explicated. Archives of Acoustics, 2005, 30, 125-128.
Landscapes but not soundscapes are planned. Today’s noise control is based on traffic noise prognosis and is confined to average sound level of traffic noise. However, the heterogeneous soundscape embraces many component sounds, background sound inclusive. Prognostic design tools are needed by which “quiet” and pleasing soundscapes can be ensured. In a psychoacoustic experiment, promising properties of soundscapes were retrieved from similarities among evolutionary spectra. These were meaningfully differentiated in accord with features of perceived soundscapes extracted by multi-dimensional scaling: (a) position and slope of loudness functions due to qualitative differences (road-traffic exposed or shielded sides of buildings), (b) clusters of shielded soundscapes relative to two types of sound-exposed soundscapes, and (c) relative contribution of direct sound to background in soundscapes. The dualistic similarity approach conveys useful knowledge for soundscape design and mitigation psychophysics.
Berglund, B., Axelsson, Ö., & Nilsson, M.E. (2006). Are similar acoustic soundscapes perceived as similar? In J. Hyurynen & R. Pääkönen (Eds.), EuroNoise 2006: Advanced Solutions for Noise Control. Tampere, Finland: European Acoustics Association, Paper SS29-355. [Available on CD]
Health guidelines are concerned with soundscapes as coherent wholes (emissions from all sounds) and everyday life also takes place in soundscapes. Current noise control focuses on sound level change for singular sources, isolated from invariant background and other component sounds. By applying a dualistic similarity approach to data sets of perceptual soundscapes and acoustic soundscapes, it was possible to meaningfully differentiate properties of acoustic soundscapes of relevance for improving urban and suburban soundscapes. Apart from the mere presence of common sounds (e.g., birds, sounds of nature or technological sounds), meaningful differentiations of soundscapes include: (1) the relative proportion of direct and shielded sounds in background soundscapes, (2) the modification of loudness/softness and eventfulness/uneventfulness by acoustic quality, and (3) the “sound signatures” traceable to the relative foregroundbackground character of perceived soundscapes. Acoustically similar soundscapes (evolutionary spectra) were not always perceived similar, because the reasons for the two types of similarities differ. This fact calls for new ways to assess the acoustic soundscapes such that adequate design tools for coherent soundscapes can be developed.
Berglund, B., Axelsson, Ö., & Nilsson, M.E. (2006). A dualistic psychoacoustic research strategy for measuring soundscape quality. In C. Burroughs & G. Maling (Eds.), Inter-Noise 2006. Honolulu: The Institute of Noise Control Engineering of the USA, Inc., Paper 034. [Available on CD]
In order to be able to design future soundscapes, tools are needed by which soundscape quality can be measured. For this purpose a “dualistic psychoacoustic research strategy” has been developed. The main goal of this strategy is to identify new ways to characterize soundscapes acoustically. The core question is how soundscapes should be measured on the one hand acoustically, on the other perceptually, such that the acoustic soundscapes that are similar (or dissimilar) would be identical to the perceived soundscapes that are similar (or dissimilar). A top down approach is favored in which tools for measuring perceived soundscape quality are first developed, and followed by developing models of measurement for acoustic soundscapes. Our multidimensional tool for measuring perceived soundscapes includes (perceived) similarity analysis for finding basic underlying dimensions and corresponding similarity analysis of acoustic (waterfall) soundscape quality. This means that this tool measures soundscape quality beyond loudness of unwanted sounds or mere sound level of predominant noise. Research on neural network models is in progress for finding appropriate acoustic measures of soundscapes.
Berglund, B., & Borg, E. (Eds.). (2003). Fechner Day 2003. Stockholm: International Society for Psychophysics.
Proceedings of the Nineteenth Annual Meeting of the International Society for Psychophysics, Larnaca Bay, Cyprus, October 19-23, 2003.
Berglund, B., Eriksen, C.A., & Nilsson, M.E. (2001). Exploring perceptual content in soundscapes. In E. Sommerfeld, R. Kompass & T. Lachmann (Eds.), Fechner Day 2001. Lengerich, Germany: Pabst Science Publishers, pp. 279-284.
At the quiet and noisy sides of buildings 69 residents of three residential areas found 414 soundscapes to be similar with regard to sounds discerned. The most frequently heard sound was road traffic. At the quiet sides, children playing, talking people, birds and unidentified sounds were more often heard indoors with windows closed than outdoors. Generally, sounds heard outdoors were louder than those heard indoors. Ventilation and traffic sounds were loudest at the quiet and noisy sides, respectively. The loudest soundscapes were found at the noisy side outdoors and the least loud at the quiet side with closed window. The perceived quality of the soundscapes were assessed with 12 attributes representing the four components adverse, reposing, affective, and expressionless (88% explained variance in PCA). The outdoor soundscapes showed predominantly high agreeableness for adverse attributes and low agreeableness for the reposing attributes and the reverse indoors with closed window. This outcome was more pronounced at the noisy side. The most livable soundscapes would tentatively include a composition of sounds that create a harmony restful to the ear and mind.
Berglund, B., Eriksen, C.A., & Nilsson, M.E. (2002). Perceptual characterization of soundscapes in residential areas. In A. Alippi (Ed.), The 17th International Congress of Acoustics. Roma, Italy: ICA Srl, vol VI, pp. 284-285. [address: ICA Srl, Via Belluno 16, Roma, Italy] (Also available on CD)
Environmental sound is perceived in the context of soundscapes. During structured walks, residents identified sounds and master scaled the loudness of these sounds together with pink noise references. Sounds most frequently discerned in soundscapes were from road traffic, cars, people, birds, buses, and ventilation systems (84-13% of the soundscapes). The perceived loudness was greatest for buses, cars, trucks, road traffic, and motor cycles (71-64 PNeq). Qualitative characterizations of the soundscapes were also made with perceived-attribute profiles. The 69 residents living in apartments in three areas characterized 414 soundscapes in four dimensions: “adverse,”, “reposing”, “affective”, and “expressionless”. All except one soundscape outdoors were classified together with the open-window indoor soundscapes at the noisy side of buildings. The exempt outdoor soundscape was classified together with all closed-window indoor soundscapes except for those at the most noisy facades.
Berglund, B., Gidlöf Gunnarsson, A., Nilsson, M.E., Åberg, C., Clark, C., van Kamp, I., Lopez Barrio, I., Stansfeld, S.A. (2004). An environmental health model for children exposed to aircraft and road-traffic noise. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 518. [Available on CD]
A children’s environmental health model was successfully tested with structural equation modeling (SEM) technique. A multi-group SEM was applied to the school and home environments of 9-10 year old children living around major UK, Dutch and Spanish airports (n=2808). An excellent fit was obtained between the general hypothetical model and the empirical multi-group data (RMSEA = 0.019; GIF = 0.96). The model shows that aircraft noise has a large impact on aircraft annoyance whereas road-traffic noise has a small impact on road-traffic annoyance; these impacts are independent of the other exposures. Moreover, aircraft noise annoyance has a small impact on symptoms and sleep disturbance whereas road-traffic noise annoyance has a large and significant impact. Children’s general health has a significant effect on children’s sleep disturbance, which also was found true for road-traffic annoyance. Notably, children’s psychological restoration indoors (but not outdoors) has a significant counteractive effect on children’s annoyance to both road-traffic and aircraft noise. Adult social support has a negligible direct effect but a significant indirect effect on sleep disturbance with psychological restoration and annoyance as intervening variables.
Berglund, B., Hassmén, P., & Preis, A. (2002). Annoyance and spectral contrast are cues for similarity and preference of environmental sounds. Journal of Sound and Vibration, 250, 53-64.
Previous research has suggested that perceived similarity is based on primarily cognitive processes, whereas preferences are based to a larger extent on affective processes. This was put to an empirical test utilizing 15 complex sounds as stimuli and 25 subjects for the assessments. Various versions of multidimensional scaling were used as a method of comparison. The results show that data analyses must take into account individual differences in similarity and non-preference. Contrary to the hypothesis expressed, both similarity and non-preference were found to be based mainly on affective responses because a major proportion of the explained variance originated from the perceived annoyance of sound. This was not true for perceived loudness or for the acoustic variables of Zwicker’s loudness and Aures’s sharpness. Spectral contrast calculated as the number of maxima in the normalized Zwicker’s specific loudness spectra was found to be the best acoustic candidate for explaining at the individual level what properties of sound cause them to be perceived as similar or non-preferred.
Berglund, B., Hojan, E., Furmann, A., & Sworek, K. (2002). Attributes of desirable acoustic environments in some rooms. Archives of Acoustics (Poland), 27(3), 249-255.
Normal hearing native Polish speaking subjects were asked to choose attributes of a desirable acoustic environment, which were presented in a list. The subjects were asked to describe the attributes that would be desirable while listening to a lecture hall, reading a book in a living room and listening to a musical performance in concert hall. Results indicate that the methods used to derive the attributes is valid, that women apply more and slightly different attributes then men and some attributes are uniformly used across the environments tested.
Berglund, B., Kihlman, T., Kropp, W., Öhrström, E. Soundscape Support to Health. Göteborg: Chalmers, MISTRA Final Report Phase 1, March 2004 (available on CD)
See separate heading (Final Report Phase 1 (Summary))
Berglund, B., Lindvall, T., & Nilsson, M.E. (2005). Noise. In: The National Board of Health and Welfare (Eds.), Environmental Health Report 2005. Extended Summary. Stockholm: The National Board of Health and Welfare, pp. 24-27.
Community noise is a widespread environmental problem in Sweden and is the form of disturbance that affects the highest number of both children and adults. Twelve-year-olds are disturbed by the same noise sources as adults, but, for children, loud music is the most annoying source, whereas road-traffic noise is most annoying source for adults. One child in every seven is annoyed by noise in or near the home and one in four is annoyed by noise in or near the school/kindergarten. One in every five report that after listening to loud music or other loud sounds. They experience ringing, squeaking, howling or buzzing in their ears, this being slightly more frequent among boys than girls. Just over one in ten report that their hearing is sometimes worse after listening to loud music. Children are exposed to hearing-impairing noise to a larger extent than in the past. Sound levels measured in kindergartens and schools exceed the limit for when ear protectors must be worn according to legislation governing health and safety at work. It is important that children’s noise exposures in kindergartens, schools and leisure environments are reduced as well as children's exposure to excessively loud music.
Berglund, B., Lindvall, T., & Nilsson, M.E. (2007). The children's community response to environmental noise. Revista de Acústica, 2007, 38 (3-4), Paper ENV-02-003.
Community noise disturbs many adults in industrialized countries and WHO considers children especially vulnerable to noise. The Swedish Children’s Environmental Health Survey estimated that 25% of the 1.5 million were up to 14-year olds (16% of the population) who lived in an apartment and/or had bedroom window facing trafficked route, track or industry. Self-reports from 12-year olds gave 25% annoyed by sounds in and close to the school, and 14% annoyed by noise in or near the home, 15% sleep disturbed, and 6% with difficulty sometimes getting a full night’s sleep. The children were found to be exposed to hearing-impairing noise to an extent not known of in the past: 2,000 4-year olds were reported to have impaired hearing and 4,000 12-year olds. Children were disturbed by the same noise sources as adults, and the most annoying sources were at school (i.e., other children, scraping sounds from chairs, loud noise when playing). Other children were also most reported source to annoyance in or near the home, followed by loud music and road traffic noise. Among the 12-year olds, 4% were annoyed by road-traffic noise at home and 4% at school. The trend of increasing noise must be reversed.
Berglund, B., & Nilsson, M.E. (2000). The potential of master scaling of perceptual attributes in social surveys. In D. Cassereau (Ed.), Inter Noise 2000. Bron, France: INRETS, vol. 3, pp. 1593-1597.
Dose-response relationships for differently exposed populations cannot be inferred to be valid for individual residents. By using the principle of master scaling in quantifying annoyance in social surveys, it is possible to “calibrate” for interindividual differences. Comparability between populations can, thus, be obtained although different residents have reported annoyances uniquely linked to their own local noise exposure. So far, master scaling has been successfully applied in field studies and tested in psychoacoustical model experiments.The “calibration” of scales for perceptual attributes has also been validated experimentally. By master scaling annoyance and other perceptual attributes, it would be possible to predict changes in these variables and to evaluate the efficiency of various noise abatement procedures.
Berglund, B., & Nilsson, M.E. (2000). Total annoyance and preceptually discernible noise sources. In D.Cassereau (Ed.), Inter Noise 2000. Bron, France: INRETS, vol. 6, pp. 3541-3544.
Questionnaire-study respondents typically attribute their annoyance to specific sounds. Obviously, these sounds can be discerned perceptually in the flow of sounds constituting the soundscape but also be integrated into total annoyance reports. Current total annoyance models integrate sound pressure levels or annoyances of singular noise sources. Total annoyance models based on energy summation for multiple noise sources are incompatible with empirical field data that unavoidably involves perceptual-cognitive integration. In a field study involving cars, buses, trucks, and MCs, total annoyance was found to be less than source specific annoyance, indicating compromise. A multiple regression equation was used to model this kind of integration and the weights were found associated with the relative “on time” of the various noise sources.
Berglund, B., & Nilsson, M.E. (2001). Variation in perceived soundscape due to shielding building and facade. In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Netherlands: Nederlands Akoestisch Genootschap (NAG), vol. 3, pp. 1253-1256.
The perceived soundscape varies in space and time. In urban residential areas, this variation is due to the particular pattern of sound emissions, acoustic transformations due to shielding buildings, and insulation and facade reflections. Residents living in road-traffic noise exposed apartment buildings (62 dB LAeq,24h) participated in structured walks. At 6 listening stations indoors and outdoors, the residents repeatedly assessed their own soundscapes with regard to perceived loudness. Each soundscape’s perceived loudness was master scaled and expressed in pink noise equivalents (PNE). The results were: (i) The indoor soundscape is considerably greater in perceived loudness at the noisy side than at the quiet side of an apartment although the corresponding difference in A-weighted sound level (LAeq) is small. (ii) The indoor-outdoor difference in perceived loudness at the road-traffic noise exposed facade of an apartment building is small although the corresponding difference in A-weighted sound level is large. It is concluded that residents’ perceived loudness of their own soundscapes during walks can be calibrated to a common scale. Evaluations of the efficiency of shielding buildings and facades may be substantially improved if perceptual measurements of the soundscapes are utilized.
Berglund, B., & Nilsson, M.E. (2001). Total annoyance (or total loudness) models of combined community sounds. Archives of the Center for Sensory Research, 6(3), 33-59.
A theoretical consequential analysis was applied to hitherto proposed psychophysical and perceptual models of total annoyance (or total loudness) of combined community sounds. The great majority of proposed models describe total annoyance in terms of source-specific annoyance or in terms of annoyance-matched sound levels. These models were accommodated in a general perceptual or a general psychophysical model. The two are shown to be mathematically equivalent under certain assumptions about the value of their constants together with assumptions about the psychophysical annoyance function for singular sounds. The analysis of the proposed models showed that model predictions were greatest for the Independent Effect Model and smallest for the Strongest Component Model, with model predictions of other models falling between these two extremes. Despite great variability, a general trend was found in the results from previous psychoacoustical experiments: The contribution of a given sound to total annoyance is less if combined with a relatively strong sound than if combined with a less strong sound. This outcome may be related to nonlinearities in response scales, interactions between combined sounds (e.g., masking), or the annoyance integration principle. Future experiments should be designed with the purpose of estimating the relative importance of these factors for total annoyance. Proposed models do not allow for “compromise” outcomes, that is, the combined sound is less annoying than the most annoying of the sounds combined. This is, however, a common outcome in field and laboratory studies. In 18 empirical studies, “compromise” outcomes were typically found if source-specific annoyance referred to sounds heard within combined sound (mainly field studies) and not, if referred to singular sounds presented alone (only laboratory studies). This call for experimental research, where singular and combined sounds are scaled for both total annoyance and source-specific annoyance as heard within combined sound.
Berglund, B., & Nilsson, (2001). M.E. Identification of sounds from traffic. Archives of the Center for Sensory Research, 6(3), 61-70.
Listeners’ ability to identify road-traffic, aircraft, or train sounds in environmental sound recordings was studied in a psychoacoustical experiment involving 16 participants. In free-labeling identification, excerpt traffic sounds were described in terms of “object” (sound-producing source) rather than in terms of perceptual attribute. The main sounds identified were traffic sounds, but a few references were also made to machine-related or water-related sources. Sounds from aircraft were easier to identify than the sounds from trains, which in turn were easier to identify than the sounds from road-traffic. This identification order was confirmed in multiple-choice and dominant-source identification tasks. Compared to free-labeling, multiple-choice identifications produced considerably more false alarms (i.e., identification of a sound source not present). For multiple-choice, several sound sources were particularly identified in the excerpt road-traffic and train sounds although the (recorded) sound was typically clearly discerned in the joint dominant-source identification task. Comparison with physical properties of sound suggested that spectral rather than temporal cues were used in sound-source identification.
Berglund, B., & Nilsson, M.E. (2001). Total and source-specific loudness of singular and combined traffic sounds. Archives of the Center for Sensory Research, 6(3), 71-93.
Unlike previous research on total loudness (or annoyance) of combined traffic sounds, the present also included the scaling of source-specific loudnesses as heard within the simultaneously presented sounds. In three experiments, the same 20 participants scaled total and source-specific loudness of pairs of road-traffic, aircraft and train sounds, with the aid of free-number magnitude estimation. The results showed that for equally loud combined sounds, source-specific loudness of both sounds will be reduced because of masking. For unequally loud combined sounds, the less loud sound will be substantially or completely reduced, whereas the louder sound will stay more or less unchanged. The total loudness gain was great for equally loud sounds combined, on average 4.5 dB expressed in equal-loudness calibrated sound level. This gain is inconsistent with energy summation, which at most would give 3 dB. Total loudness (Ytot|ab) and source-specific loudness heard within combined sound (Ya|ab,Yb|ab) were found to adhere to a general loudness integration model: Ytot|ab = ( Yna|ab + Ynb|ab)1/n, where different values of the constant n define arithmetic summation (n = 1), Euclidean summation (n = 2), and the strongest component principle (n =∞). The empirical n-values were found to range from 2.5 to 2.9, which means that total loudness is less than the arithmetic or Euclidean sum but greater than that of the loudest sound. Corresponding n-values for source-specific loudness of traffic sounds heard alone (Ya|a,Yb|b) ranged from 4.1 to 4.2. Thus, our comprehensive findings for combined traffic sounds are in disagreement with the most commonly proposed models: arithmetic summation of source-specific loudnesses, the strongest component principle, or source-corrected energy summation.
Berglund, B., & Nilsson, M.E. (2001). Total and source-specific loudness of simultaneous and time-separated traffic sounds. Archives of the Center for Sensory Research, 6(3), 95-103.
A road-traffic and train sound of constant duration at a “soft” or “loud” level of (perceived) loudness were combined in various patterns of overlap in time (no, total, or partial overlaps). These combined sounds were scaled with regard to total and source-specific loudness. The main finding was that the relationship between total and source-specific loudness depends on the relative level, as well as, on the temporal relation of the two traffic sounds combined. So called “compromise” outcomes, in which source-specific loudness is greater than total loudness, were commonly found for combinations of unequally-loud sounds separated in time, but not for equally-loud sounds or simultaneously presented sounds. This agrees with the idea that total loudness of time-separated, unequally-loud sounds is “averaged” over the complete time period of these combined sounds whereas the source-specific loudness of the louder (or the softer) sound is averaged over the comparatively shorter time period during which it is heard. This way of assessing loudness of combined sounds may very well in principle be valid also for annoyance and thus explain compromise outcomes in field studies of combined noise.
Berglund, B., & Nilsson, M.E. (2002). Soundscapes perceived indoors and outdoors at quiet and noisy sides of apartment buildings. In A. Selamet, R. Singh & G.C. Maling (Eds.) Inter Noise 2002. Transportation Noise. Dearborn, MI. USA: International Institute of Noise Control Engineering (I-INCE), Paper N 488. (Available on CD)
The effects of shielding buildings or of insulation and façade reflections on outdoor and indoor soundscapes were assessed in traffic-noise exposed residential areas. The residents of apartments participated in structured listening walks including six listening stations in each of four differently exposed areas. In all, 96 residents repeatedly assessed their own soundscapes with regard to perceived loudness which was master scaled and expressed in pink noise equivalents (PNE). The main results were: (a) The indoor soundscape was considerably greater in perceived loudness at the noisy side than at the quiet side of an apartment although the corresponding difference in various measures of the acoustical soundscape was small (LAeq, LCeq, Zwicker loudness, L10, N10). The same discrepancy between perceptual and acoustical measures was found for perceived “annoyance” as constructed from scales of five adverse perceptual attributes (disturbing, noisy, hard, intrusive, stressful); (b) The indoor-outdoor difference in perceived loudness for the road-traffic noise exposed façade of an apartment building was small although the corresponding difference in the various measures of the acoustical soundscape was large. The same result was again found for perceived “annoyance” as for perceived loudness. Thus, the differences in acoustic levels are not well correlated with the differences in perceived levels. A main conclusion is, therefore, that residents’ outdoor and indoor soundscapes may be substantially improved if shielding buildings, insulation and façade reflections are optimized efficiently to meet psychoacoustical rather than current acoustical criteria.
Berglund, B., & Nilsson, M.E. (2003). Identification of sounds from traffic. Perceptual and Motor Skills. 97:675-688
Listeners’ ability to identify road-traffic, aircraft, or train sounds in environmental sound recordings was studied in a psychoacoustical experiment involving 16 participants. In free-labeling identification, excerpt traffic sounds were described in terms of “object” (sound-producing source) rather than in terms of perceptual attribute. The main sounds identified were traffic sounds, but a few references were also made to machine-related or water-related sources. Sounds from aircraft were easier to identify than the sounds from trains, which in turn were easier to identify than the sounds from road-traffic. This identification order was confirmed in multiple-choice and dominant-source identification tasks. Compared to free-labeling, multiple-choice identifications produced considerably more false alarms (i.e., identification of a sound source not present). For multiple-choice, several sound sources were particularly identified in the excerpt road-traffic and train sounds although the (recorded) sound was typically clearly discerned in the joint dominant-source identification task. Comparison with physical properties of sound suggested that spectral rather than temporal cues were used in sound-source identification.
Berglund, B., & Nilsson, M.E. (2004). Soundscapes perceived in built environments. In: ICA 2004. Tokyo, Japan: Acoustical Society of Japan, vol. I, pp. 259-260.[also available on CD]
Perceived soundscapes were assessed in listening walks with residents in road-traffic noise exposed residential areas. Shielded sides of buildings provided soundscapes that were more “soothing” and “pleasant” than soundscapes at road-traffic noise exposed sides of buildings. In significantly road-traffic noise exposed areas (LAeq, 24h>55dB), shielded sides count not provide soundscapes as positive as in a “quiet” residential area (LAeq,24h<50dB). Positive aspects of soundscapes, e.g., “pleasant” and “soothing”, were not predictable from measurements of A-weighted sound level or Zwicker loudness. This suggests that a new kind of method is needed for predicting soundscape quality in residential areas of the future.
Berglund, B., & Nilsson, M.E. (2006). On a tool for measuring soundscape quality in urban residential areas. Acta Acustica united with Acustica, 92, 938-944.
An attribute-profiling tool, customized for 106 residents’ structured listening walks, was developed for measuring “soundscape quality” in 24 kinds of listening places representing four urban residential areas exposed to road-traffic noise. The tool’s 12 attributes were matched to the soundscape on a scale from 0 to 100%. The attributes were: soothing, pleasant, light, dull, eventful, exciting, stressful, hard intrusive, annoying, noisy and loud. In total, the soundscape quality of 636 unique 30-s soundscapes was measured. For good soundscape quality (pleasant and soothing) to predominate outdoors, the overall sound level of soundscapes had to be below ca. 50 dB LAeq,30s. Indoor soundscapes (closed windows) at exposed sides of buildings were found to be of inferior quality compared to outdoor soundscapes at shielded sides. This was true although the former soundscapes were 14 dB LAeq,30s lower than the latter. A PCA analysis of the 12-attribute profiles of the 24 kinds of listening places shoed that residents actually perceived “signature” of soundscape quality linked to the origin of the soundscapes, whether indoor or outdoors. All soundscapes at shielded sides indoors with closed windows clustered together with the indoor and outdoor soundscapes in the low road-traffic noise exposed residential area. Conversely, at buildings ides with high traffic-noise exposure, all soundscapes, outdoors or indoors with open window, clustered together with their outdoor soundscapes at the shielded d sides. The new attribute-profiling tool is promising because it measures soundscape quality beyond unwanted sounds and mere sound level of predominant noise.
Berglund, B., & Nilsson, M.E. (2007). Master scaling in psychoacoustics. Revista de Acústica, 2007, 38 (3-4), Paper PPA02-001.
A main problem in environmental psychoacoustics is that the conditions for repeated measurement of sounds are not fulfilled. Sounds appear and disappear in the soundscapes which are ever changing with time. This calls for calibrated one-point measurement on a perceptual continuum, in addition to the acoustic measurement. Master scaling provides this by using a set of references for defining an invariant context, within which a target sound or soundscape is measured by one human observer. Thus, each observer’s measures are quality assured through references, and target sounds are measured on a calibrated master scale. Four psychoacoustic applications are presented: (1) To determine the loudness of shots from cannons at different distances to source using impulse sound or pink noise as reference; (2) To determine sound quality contributions to loudness for power line noise and community noises; (3) To determine low-frequency contributions to the loudness of road traffic noise; and (4) To determine soundscape loudness of places during listening walks in residential areas of different cities. The four applications illustrate the needs and potentials of a measurement system for sound perception as such.
Berglund, B., Nilsson, M.E., & Axelson, Ö. (2006). Soundscape perception. In: Proc. Joint Baltic-Nordic Acoustical Meeting (BNAM). Gothenburg, Sweden: The Swedish Acoustical Society
Annoyance research typically focuses on single sources and on adverse effects of noise. In contrast, soundscape research focuses on the total sound environment, including all its positive and negative aspects. A major challenge in soundscape research is to develop methods for measuring the perceived soundscape. In the research program “Soundscape Support to Health”, we have developed new methods for this purpose, including listening tests in the laboratory, listening walks in the field and questionnaire studies targeted on the soundscape. We have thus identified major perpetual dimensions of soundscapes (pleasantness and eventfulness), linked these features to important acoustical and informational properties of soundscapes (type of sources), and explored the effect of noise mitigation on soundscape perception. Our research show (a) that pleasantness of soundscapes is related to the presence of natural sounds, whereas eventfulness is related to the presence of sounds from humans, (b) that traffic noise should be reduced to below 50 dBA, in order to have a chance to create good outdoor soundscapes in urban residential and recreational areas, and (c) that mitigation efficiency in sound level of various barriers and facades may overestimate corresponding perceptual mitigation efficiency. Based on these findings, new tools for ‘green labelling’ of soundscapes are being developed.
Berglund, B., Nilsson, M.E., & Axelsson, Ö. Sounscape psychophysics in place. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 114. [Available on CD]
Based on exposure-response curves for annoyance, immission values less than 55 dB LAeq,16h is typically required for one type of traffic noise at a time. Such energetic time-averages do neither convey information on sound components, nor on soundscape structure and dynamics. Due to the ecological fallacy, population-based annoyance curves are inappropriate for predicting mitigation efficiency and for creating good soundscapes. Thus, soundscape psychophysics has to be put in place, both indoors and outdoors. Research showed that: (i) Sound level overestimates mitigation effects on the perceived soundscapes outdoors with and without barriers and indoors with open and closed windows. (ii) The mix of positive-and adverse characteristics of soundscapes makes residents accept higher sound levels at outdoor (<50 dB) than indoor places (30-40 dB). (iii) A mix predominated by nature and human-activity sounds, over mechanical sounds, is critical for good soundscape quality, which is measured in metric space as regards pleasant-unpleasant, exciting-boring, eventful-uneventful, and chaotic-tranquil. (iv) The Soundscape Walk© is launched in which a panel assesses the quality of soundscapes in residential areas and, soundscape places are classified according to total perceptual valuations.
Berglund, B., Nilsson, M.E., & Pekala, P. (2004). Towards certification of indoor and outdoor soundscapes. In: Inter-Noise 2004. Prague, Czech Republic, August 22-25, 2004. (in press).
A diagnostic system for soundscape certification is proposed which builds on a neural network classifier. A radial basis network was successfully trained and tested on independent subsets of 30-s soundscape data. Acoustic input was 1/3-octave-band spectra and perceptual output profiles of 12 perceptual-emotional attributes. Thus, a differentiation and classification of acoustic soundscapes was learned from the perceived soundscapes. A new neural network is now being trained which utilizes more detailed acoustic information (“waterfalls”: Ln,fast, T, 1/3-octave bands) from a database of 894 30-s soundscapes from road-traffic noise exposed residential areas (45-65 dB LAeq,24h); binaural and monaural recordings and perceptual-emotional attribute profiles from residents’ listening walks. The currently developed diagnostic system is intended for green labeling of residential soundscapes. The neural network is intended as a design tool for city planners, architects, materials producers, etc. Acoustic soundscapes can for example be optimized in a future database of consequences of building plans, design of facades, sound insulation, etc.
Bluhm, G., Nilsson, M.E., & Rosenlund, M. (2006). Buller. [Noise.] In Barns hälsa och miljö i Stockholms län 2006, [Childrens health and environment in Stockholm,] pp. 113-126. Stockholm: Stockholms läns landsting, Regional Miljöhälsorapport, 2006. (ISBN: 91-631-9023-0). In Swedish
Noise is an environmental problem that affects children both at school and home. This chapter summarizes the results on noise disturbances from the “Children’s environment and health survey” conducted in Stockholm County in year 2003. It was found that children were most disturbed by noise at school. Thirty per cent of all 8- and 12 year old children in Stockholm County were annoyed by noise at school, mainly noise from other children. Children in Stockholm County were exposed to more noise in their homes than children in other parts of Sweden. Almost 50 % of children in inner city Stockholm and 20 % in the rest of the County were living in apartments with windows facing a major road, railway or industry. Eighteen per cent of all 8- and 12-year olds were disturbed by noise in their homes. Slightly less than 6 % reports that noise disturbed school homework or speech communication, whereas 4 % reported difficulties in falling asleep due to noise in the home. Approximately three per cent of parents to all 4-, 8- and 12- year old children reported that their children have reduced hearing, and three per cent of 8- and 12-year old children reported that they have tinnitus. It is concluded that noise in dwellings and schools should be reduced in order to provide good and healthy sound environments for children. Furthermore, the sound environment should be considered already at the planning stage, in order to minimize indoor and outdoor noise exposure in future dwellings and schools.
Botteldooren, D., De Muer, T., De Counsel, B., Berglund, B., & Lercher, P. (2005). An LAeq is not an LAeq. Journal of the Acoustical Society of America, 117(4), Pt. 2, 2616.
Classical dose response relationships for environmental noise annoyance have been based on Ldn or Lden. These exposure measures are essentially based on an energy averaging measure, LAeq. Differences between groups of sources (e.g., continuous or event based) are accounted for by using separate dose-effect relationships. In society today, one often sees that event loudness is traded for number of events which is perfectly acceptable within the LAeq based annoyance concept. Clearly a more unified theory for noise annoyance is needed to fully account for the effect of such trade-offs. In this paper a model implementing such a theory is presented. The perceptual model starts from the premises that a sound event has to be noticed for it to contribute to overall annoyance. The model accounts for the fact that noticing a noise event not only depends on the level of the event itself but also on background noise, sound insulation and acoustic characteristics of the dwelling, level of attention, etc. The severity of the effect of a noticed sound on overall annoyance is assumed to primarily depend on the signal to noise ratio. The model allows to account for modifiers such as previous exposure, noise sensitivity, and coping. The model results are compared to the findings of a recent field experiment. Conclusions based on calculated and experimental trends will be presented.
Botteldooren, D., De Counsel, B., Dekoninck, L., De Muer, T., Berglund, B., Nilsson, M., & Lercher, P. (2005). Perceived Noise Annoyance Caused by Maglev Trains. Management Summary. Gent, Belgium: Department of Information Technology, Ghent University.
The annoyance impact in realistic settings of traffic noise was assessed for one, two or four train passages, primarily high-speed trains, or continuous road traffic noise. An innovative system for selecting representative participants from the Dutch population was implemented, as regards a number of critical variables (age, gender, level of education, noise sensitivity, reported anxiety, home exposure to train and road traffic noise, general quality of living environment, and general health). In total, 1500 candidate participants responded to the specifically constructed questionnaire with items from a nation-wide Dutch survey and the Eurobarometer. Participants with typical Dutch response profile were recruited on a first come, first serve basis (in total 80 plus 21 extra persons. In the experiment, 5-7 participants were seated to be relaxed and to be reading a magazine or newspaper. The were served refreshments. Traffic noise was reproduced in outdoor loudspeakers in an ecologically valid way. Every 10 min, participants were asked to assess noise annoyance. At the beginning and at brief intervals during the experiment, participants assessed the annoyance of a set of 7 reference sounds utilized for master scaling. At the same average façade exposure, no significant annoyance difference was neither found for Maglev and TGV, nor for conventional trains and the high-speed trains (only tested up to 65 dBA). The latter result contradicts Vos et al.’s earlier findings. Neugebauer at al.’s results fall within the spread in annoyance values due to distance to the track and vehicle speed that we observed. Field surveys have shown that for the same average sound level, railway noise evokes less annoyance than dense road traffic noise, at least for a certain interval of levels. Although our experiment included several of the factors that may contribute to this effect, we were unable to observe this kind of effect, except for the case when the sounds were recorded at a distance of more than 100 m.
Botteldooren, D., De Coensel, B., De Muer, T., Berglund, B., Nilsson, M.E., & Lercher, P. (2005). Experimental investigation of noise annoyance caused by high-speed trains. In J.L. Bento & D. Alarcao (Eds.), ICSV 2005–Twelfth International Congress on Sound and Vibration (Paper 846). Lisbon: IIAV/CAPS-IST. (Available on CD)
The difference in perceived noise annoyance caused by train and highway noise at the same averaged noise level, has led to the introduction of the ’railway bonus’. This bonus has found its way to the noise legislation in many countries, leading to more relaxed restrictions on time averaged noise levels, LAeq. With the introduction of high-speed trains and train-like transportation systems based on magnetic levitation, the question has risen whether the railway bonus can still be applied. The paper reports on an experiment that was conducted to answer this question. The experiment that was performed was different from previous efforts in many ways. Most importantly, the experiment was conducted in a realistic setting, a holiday cottage, and participants were asked to engage in light daily activities such as reading a magazine during the tests. Traffic noise was reproduced in an ecologically valid way, using outdoor loudspeakers. Every ten minutes the participants were asked to judge noise annoyance. At the beginning of the experiment and after about 1.5 hours the participants were also asked to rate a set of 7 master scaling sounds. After this experiment, a more conventional listening test was conducted using 45-s excerpts. The experiment was also unique in the way that 100 participants were selected to be representative for the Dutch population. The selection procedure involved careful screening based on a survey that was administered at the doorstep of 1500 persons’ homes.
Clark, C., Stansfeld, S., Berglund, B., Nilsson, M.E., Gidlöf Gunnarsson, A., van Kamp, I., van Kempen, E., & Lopez Barrio, I. (2006). Psychological restoration, coping strategies and children’s cognitive performance in the RANCH study. In C. Burroughs & G. Maling (Eds.), Inter-Noise 2006. Honolulu: The Institute of Noise Control Engineering of the USA, Inc., Paper 454. [Available on CD]
The RANCH study found a linear exposure effect association between chronic aircraft noise exposure at primary school and the impairment of children’s reading comprehension, in the Netherlands, Spain and the United Kingdom. This paper presents multilevel modelling analyses, exploring psychological mechanisms, which may moderate the effect of aircraft noise on children’s cognition. Psychological restoration – the process whereby places which afford tranquillity and relaxation are utilized to reduce stress and promote well being – has been shown to reduce the adverse effect of noise on children’s annoyance responses. This paper examines whether having places for psychological restoration at home, moderates the adverse effects of chronic aircraft noise exposure at school on children’s cognition. In addition, the effectiveness of coping strategies in relation to noise exposure at school are examined – are specific coping strategies associated with less impairment of cognition?
De Coensel, B., Botteldooren, D., Berglund, B., Nilsson, M.E., De Muer, T., & Lercher, P. (2007). Experimental investigation of noise annoyance caused by high-speed trains. Acta Acustica united with Acustica, 2007, 93, 589-601.
A field experiment was conducted, to investigate the possible differences in perceived annoyance of noise caused by the traffic on a highway, by conventional trains and by high-speed trains, both conventional and magnetic levitation. The design of the experiment was different from earlier research in many ways. Most importantly, it was conducted in a realistic setting, a holiday cottage, and during the tests the participants were engaged in light daily activities. Traffic noise was reproduced in an ecologically valid way through loudspeakers placed outdoors. A stepwise selection of panelists was based on a screening questionnaire that was administered at the doorstep of 1500 persons living in the test site surroundings. The 100 panelists were selected to be representative of the Dutch population. The LAeq-annoyance relationships determined for the conventional high-speed train and for the magnetic levitation high-speed train did not differ significantly. The annoyance differences observed could be explained in terms of train noise differences in rise time and in propagation effects due to the distance between the track and the listening (recording) position.
De Coensel, B., Botteldooren, D., Debacq, K., Nilsson, M.E., & Berglund, B. (2007). Soundscape classifying ants. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 431. [Available on CD]
In this paper, the use of fuzzy ant clustering in classifying a large database of environmental soundscape recordings is outlined. Fuzzy ant clustering is a soft computing technique inspired by the clustering behaviour observed in colonies of several ant species. Virtual ants or “agents” move through the database, “pick up” soundscape recordings and drop them in places where similar recordings are present. Similarity of soundscape recordings is expressed by fuzzy resemblance of the shape of the sound-pressure-level histogram, the frequency spectrum and the spectrum of temporal fluctuations, representing loudness, spectral and temporal content. The fuzzy IF-THEN rules, governing the behaviour of the virtual ants, are optimized using a specially adapted genetic algorithm, in order to achieve an optimal set of homogeneous clusters. Advantages of this approach, as compared to traditional clustering methods, are that no a priori information, such as the desired number of clusters, is needed, and that a more flexible set of indicators can be used. The clustering model is validated on a database of acoustic measurements of 1116 soundscapes, recorded in 16 urban parks in Stockholm, and the results are compared with visitor survey data on soundscape quality.
De Coensel, B., Botteldooren, D., De Muer, T., Lercher, P., Berglund, B., & Nilsson, M.E. Observation on the influence of non-acoustical factors on perceived noise annoyance in a field experiment. In: Inter-Noise 2005. Rio de Janeiro: Brazilian Acoustical Society (SOBRAC), Paper 2028. [Available on CD]
The influence of non-acoustical factors on noise annoyance was studied in a unique field experiment. An innovative system was implemented for selecting representative participants from the Dutch population, as regards age, gender, level of education, noise sensitivity, reported anxiety, pre-exposure to train and road traffic noise, general quality of the living environment, and general health. It was grounded in 1500 participants’ responses to a specifically constructed questionnaire, which contained items from a nation-wide Dutch and Eurobarometer surveys. Finally, 100 representative participants were selected. During the experiment, which took place in a realistic setting (living room of holiday cottage), groups of 5-7 participants were asked to be seated, relax, reading a magazine or newspaper and were served refreshments. During their stay, traffic noise was reproduced in an ecologically valid way via outdoor loudspeakers. Every ten minutes, the participants were asked to assess traffic noise annoyance. At the beginning and after at least 1 hour of the experiment, participants were also asked to scale the annoyance of a set of 7 reference sounds utilized for master scaling. In this field experiment, residual effect on noise annoyance was found from non-acoustical factors like noise sensitivity, environmental worry, and health status. Even after master scaling, it seems that inter-individual variation in traffic-noise annoyance remains which is dependent on certain important non-acoustical factors.
De Muer T., Botteldooren, D., De Coensel, B., Berglund, B., Nilsson, M.E., & Lercher, P. A model for noise annoyance based on notice-events. In: Inter-Noise 2005. Rio de Janeiro: Brazilian Acoustical Society (SOBRAC), Paper 2033. [Available on CD]
Exposure effect relationships for environmental noise annoyance have been based on Ldn or Lden, two measures based on energy averaging LAeq. For event based sources, typically, event sound level is traded for number of events in modeling the impact of noise on annoyance. Clearly, a more united theory for noise annoyance is needed to account fully for the effect of such trade-offs. The model presented in this paper is grounded in the hypothesis that noise annoyance is primarily determined by noticed intruding sounds. The model starts by careful prediction of the occurrence of 'notice-events'. It takes into account signal to noise ratio of the target sound with respect to the ambient (natural) background level, the indoor background level, the activity the listener is engaged in, etc. Noticed events are appraised via an emotional and a cognitive path. As a test case, our model is applied to annoyance and acoustic data from a field experiment in a natural setting in which participants were engaged in other activities than focused listening to sounds. Target sounds were train noise with varying event intensity and number of events, and free flow road traffic noise from highways and roads. The outdoor background levels were 39-49 dBA.
Forssén, J. (2000). Calculation of noise barrier performance in a turbulent atmosphere by using substitute sources above the barrier. Acustica, 86, 269-275.
The paper presents a model that can be used for calculating the sound reduction by a noise barrier in a turbulent atmosphere. The field due to the acoustic source is substituted by a distribution of sources above the barrier (here called substitute sources). The mean power at the receiver is calculated as line-of-sight propagation through a turbulent atmosphere from all substitute sources using a mutual coherence function. In this study the strengths of the substitute sources are calculated using the Kirchhoff approximation. The calculated results show good over-all agreement with those from using a parabolic equation method (PE).
Forssén, J. (2000). Calculation of noise barrier performance in a turbulent atmosphere by using substitute sources above the barrier. In D. Cassereau (Ed.), Inter Noise 2000. Bron, France: INRETS, vol. 3, pp. 1443-1446.
A model is presented that can be used for calculating the sound reduction by a noise barrier in a turbulent atmosphere. The field due to the acoustic source is substituted by a distribution of sources above the barrier (here called substitute sources). The mean power at the receiver is calculated as line-of-sight propagation through a turbulent atmosphere from all substitute sources using a mutual coherence function. In this study the strengths of the substitute sources are calculated using the Kirchhoff approximation and a two-dimensional geometry. The calculated results show good agreement with those from using a parabolic equation method.
Forssén, J. (2000). Calculation of noise barrier performance in a turbulent atmosphere by using substitute sources with random amplitudes. In Proceedings, 9th Long Range Acoustic Propagation Symposium, The Hague, Netherlands, pp. 16-26.
This paper studies the influence of turbulence on the sound reduction by a thin screen with varying height. In the model used, the field due to the acoustic source is substituted by a distribution of sources above the barrier (here called substitute sources). The amplitudes of the substitute sources are randomly perturbed to simulate the effect of a turbulent atmosphere. At the receiver the mean power is calculated from a number of realisations. The results are compared to those from using a mutual coherence function between all substitute sources. In this study only two-dimensional situations are considered. The Kirchhoff approximation is used to calculate the strengths of the substitute sources.
Forssén, J. (2000). Influence of atmospheric turbulence on noise reduction by barriers - an engineering method based on a scattering cross-section. Appendix in Nord 2000 Report. [http://www.delta.dk/nord2000]
The prediction scheme presented here uses a small number of pre-calculated data to predict the power scattered by atmospheric turbulence into an acoustic shadow. The scheme is based on a model by G. Daigle, which is developed for a thin screen on a hard ground with the noise source and the receiver on the ground surface. In the further developed prediction scheme, presented here, transformations are applied to find the scattering for a change in frequency or in geometrical length scale. The frequency transformation is enabled by assuming a Kolmogorov turbulence model. Moreover, the scheme allows elevated source and receiver positions above a ground surface and general barrier configurations. According to the model, the influence of the turbulence scattering on the sound reduction by a barrier grows when the geometry is increased in scale or when the frequency is increased.
Forssén, J. (2001). The influence of atmospheric turbulence on barrier sound reduction. Göteborg, Sweden: Chalmers University of Technology, Applied Acoustics, F 01-04. (Ph.D. Thesis)
Numerical modelling and measurements are used for studying the reduced performance of a noise barrier, caused by a turbulent atmosphere. For the numerical studies, a parabolic equation method (PE) is extended to model situations with a thin screen in a turbulent atmosphere. A scattering cross-section method is also extended to take into account source and receiver positions above a ground surface, and scaling properties are used to generate an efficient prediction scheme. A substitute-sources method (SSM) is developed, which is numerically faster than the PE. Both two and three-dimensional implementations are studied, from which it is concluded that the sound level can be well predicted for a large variety of situations using a two-dimensional model. The results show that the increase in sound pressure level caused by turbulence can be large at higher frequencies and significant as an A-weighted level.
Forssén, J. (2002). Calculation of noise barrier performance in a three-dimensional turbulent atmosphere using the substitute-sources method. In A. Alippi (Ed.), The 17th International Congress of Acoustics. Roma, Italy: ICA Srl. [address: ICA Srl, Via Belluno 16, Roma, Italy], (Avaliable on CD)
Substitute sources between a noise barrier and a receiver are used to calculate the effect of atmospheric turbulence on the barrier sound-reduction. The method is further developed to be applicable to three-dimensional situations with both low and high barriers. Calculations are made for a thin, hard screen, without the influence of a ground surface. The Kirchhoff approximation is applied for the low screens and a more accurate diffraction model is used for the higher screens. The calculated results are compared to corresponding results for two-dimensional situations, also by using the substitute-sources method (SSM). The two and the three-dimensional calculations give very similar results, which indicate that, for a large variety of situations, only two-dimensional models are needed. The results are also compared to those obtained using a scattering cross-section method, which predicts a much weaker influence of turbulence than the SSM, but mainly shows the same trend in the results that the turbulence influence is large only within a range of lower screen heights.
Forssén, J. (2002). Calculation of noise barrier performance in a three-dimensional turbulent atmosphere using the substitute-sources method. Acustica, 88, 181-189.
Substitute sources between a noise barrier and a receiver are used to calculate the effect of atmospheric turbulence on barrier sound reduction. The method is extended for application to three-dimensional situations with both high and low barriers. Calculations are made for a thin, hard screen, without the influence of a ground surface. The Kirchhoff approximation is applied for the low screens and a more accurate diffraction model is used for the higher screens. The calculated results are compared with corresponding ones for two-dimensional situations, by using the substitute-sources method (SSM) also. The two and three-dimensional calculations give very similar results, which indicates that, for a large variety of situations, only two-dimensional models are needed. The results are also compared with those obtained using a scattering cross-section method which, although it predicts a much weaker influence of turbulence than the SSM, shows mostly the same trend, namely that the turbulence influence is large only within a range of lower screen heights.
Forssén, J. (2002). Sound propagation in a turbulent atmosphere: An approach using substitute sources. In Proceedings, Tenth International Symposium on Long-Range Sound Propagation, Grenoble, France, September 12-13, 2002.
In the extended substitute-sources method (SSM), presented here, multiple substitute surfaces are used along the propagation path. The atmospheric turbulence causes a transfer of the initially coherent field into a residual, random field along the propagation path. The mean sound level at the receiver position is found from uncorrelated addition of the substitute surfaces' contributions. The calculation of each contribution is based on a mutual coherence function (MCF) for a turbulent atmosphere. The strength of the substitute sources and the Green functions to the received pressure are calculated for a non-turbulent atmosphere, here by using a fast field program (FFP). A special MCF for the residual field is derived. Examples are calculated for a turbulent atmosphere with upward refraction or without refraction. The results are compared with those from a parabolic equation method (PE) for the refractive cases and with an analytical solution otherwise. Good agreement is shown in the results, which indicates that the SSM could be useful for predictions of outdoor sound propagation.
Forssén, J. (2002). Sound propagation in a turbulent atmosphere: An approach using substitute sources. In Proceedings, Forum Acusticum, Sevilla, Spain, 2002. (Available on CD)
The substitute-sources method (SSM) was previously implemented for a single noise barrier in a turbulent atmosphere by applying a substitute surface between the barrier and the receiver. Here, the method is extended, aiming to more general applicability to traffic noise propagation in urban environments. Examples are calculated for a turbulent atmosphere with upward refraction or without refraction. The results are compared with those from a parabolic equation method (PE) for the refractive cases and with an analytical solution otherwise. The results show good agreement, which indicates that the SSM could be useful for predictions of outdoor sound propagation.
Forssén, J. (2004). An investigation of the extended substitute-sources method for sound shielding by a wedge in a turbulent atmosphere. In: Proc. 11th Long Range Sound Propagation Symposium. Fairlee, Vermont, USA: University of Mississippi, National Center for Physical Acoustics, June 2004.
The turbulence in the atmospheric boundary layer influences the sound propagation. The effect can be strong especially in acoustic shadow regions, which can be caused by refraction, ground attenuation or the geometry, e.g. by a noise barrier. Here, a shielding situation with a wedge is studied with an extended substitute-sources method (Extended SSM). In the extended method the sound field is separated into a random part, due to the turbulence, and a coherent part. The propagation is calculated forward in steps from the source to the receiver via substitute surfaces. At each surface the field separation into random and coherent parts is calculated. The field at the receiver is found from adding the coherent contribution from the last surface to the other surfaces’ contributions, for which a mutual coherence factor for the random fields is used. Effects of varying the number of substitute surfaces are studied, as well as the sound level increase due to the turbulence.
Forssén, J. (2005). An analytical solution for a low barrier in a turbulent atmosphere. In: Proc. Forum Acusticum 2005. Budapest, Hungary: OPAKFI Tudományos Egyesület, 2005. [Available on CD], (ISBN 963 8241 68 3).
Buildings and other kinds of sound barriers are commonly used to reduce traffic noise. Atmospheric turbulence causes scattering of sound into the shielded zones created by barriers. The sound level increase is expected to be significant usually for large geometries, and at higher frequencies. For steep geometries, i.e. with a high barrier close to the source or to the receiver, a scattering cross section based model can be used to predict the increase in sound level. Here, another approach is used, which is applicable to flat geometries, i.e. where the barrier is low in comparison to its distance to both the source and the receiver. The work is based on a previously developed substitute sources method (SSM). A two-dimensional modelling is done and no ground surface is considered. To numerically solve the full SSM formulation of the problem is computationally demanding due to a double integral. To reduce the computational cost, an analytical solution is derived. As an intermediate step an expression containing a single integral is found, which enables a numerically fast method. The full SSM formulation is used as reference, and agreement between the SSM and the fast method is reasonably good. The analytical solution involves further approximations and has a smaller range of validity than the fast method. Additional restraints are formulated for the applicability of the analytical solution.
Forssén, J., & Blanc-Benon, Ph. (2004). Further applications of the substitute-sources method. In: ICA 2004: Acoustical Science and Technology for Quality of Life. Tokyo, Japan: Acoustical Society of Japan, vol. I, pp. 129-132. [Also available on CD], (ISBN4-9901915-6-0).
A substitute-sources method (SSM) was developed and tested for sound propagation in a turbulent atmosphere, including upward refraction [Forssén, J. An extended substitute-sources method for a turbulent atmosphere: Calculations for upward refraction. Acustica–Acta Acustica, Vol. 89, 2003, pp. 225-233]. In the present paper a situation with turbulence and a non-flat terrain is studied. A comparison with the results from a parabolic equation method (PE) shows good agreement.
Forssén, J., & Hornikx, M. (2006). Statistics of road traffic noise in shielded urban areas: An initial study of A-weighted levels. In J. Hyurynen & R. Pääkönen (Eds.), EuroNoise 2006: Advanced Solutions for Noise Control. Tampere, Finland: European Acoustics Association, Paper SS20-237 [Avaliable on CD].
In the context of community noise and its negative effects, the noise descriptors used are usually long-term equivalent levels and, sometimes, maximum levels. An improved description could be achieved by including the time variations of the noise. Here, the time variations of A-weighted road traffic noise levels have been studied. Of special interest are situations with a shielded courtyard. For numerical results, a ray-tracing model has been used for calculating the sound propagation, and the traffic has been modelled as a Poisson process. A numerical study has been performed, where the statistics of A-weighted levels have been investigated for different situations with varying traffic flows. Also, results from an in-situ measurement have been compared with those from the numerical model, showing acceptable agreement. It is shown both by numerical modelling and measurements that the time variations in noise level are smaller in a courtyard than in a corresponding directly exposed situation. An additional conclusion is that the noise reduction of the maximum level can be significantly higher than that of the equivalent level.
Forssén J., & Hornikx M. (2006). Statistics of road traffic noise in shielded urban areas: An initial study of A-weighted levels. In: Proc. Joint Baltic-Nordic Acoustics Meeting (BNAM 2006), Gothenburg, Sweden: The Swedish Acoustical Society.
In the context of community noise and its negative effects, the noise descriptors used are usually long-term equivalent levels and, sometimes, maximum levels. An improved description could be achieved by including the time variations of the noise. Here, the time variations of A-weighted road traffic noise levels have been studied. Of special interest are situations with a shielded courtyard. For numerical results, a ray model has been used for calculating the sound propagation, and the traffic has been modelled as a Poisson process. A numerical study has been performed, where the statistics of A-weighted levels have been investigated for different situations with varying traffic flows. Also, results from an in-situ measurement have been compared with those from the numerical model, showing acceptable agreement. It is shown both by numerical modelling and measurements that the time variations in noise level are smaller in a courtyard than in a corresponding directly exposed situation. An additional conclusion is that the noise reduction of the maximum level can be significantly higher than that of the equivalent level.
Forssén, J., & Hornikx M. (2006). Statistics of A-weighted road traffic noise levels in shielded urban areas. Acta Acustica united with Acustica, 92(6), 998-1008.
In the context of community noise and its negative effects, the noise descriptors used are usually long-term equivalent levels and, sometimes, maximum levels. An improved description could be achieved by including the time variations of the noise. Here, the time variations of A-weighted road traffic noise levels have been studied. Of special interest are situations with a shielded courtyard. For numerical results, a ray model has been used for calculating the sound propagation, and the traffic has been modelled as a Poisson process. With this model the statistics of A-weighted levels have been investigated for different situations with varying traffic flows. Results from an in-situ measurement have been compared with those from the numerical model, showing acceptable agreement. It is shown both by numerical modelling and measurements that the time variations in noise level are smaller in a courtyard than in a corresponding directly exposed situation. One of the additional conclusions is that the noise reduction of the maximum level can be significantly higher than that of the equivalent level.
Forssén, J. and Hornikx, M. (2007) Statistics of road traffic noise levels in shielded urban areas. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 119. [Available on CD]
Usually long-term equivalent levels and maximum levels are used for describing noise immission within the context of community noise and its negative effects. By including time variations of the noise, an improved description of the negative effects may be achieved. Here, the time variations of road traffic noise have been studied concerning A-weighted levels and third-octave band levels. Of special interest are situations with a courtyard shielded from traffic noise. For numerical results, a ray model is used for calculating sound propagation with the traffic modelled as a Poisson process. It is shown both by numerical modelling and measurements that the time variations in noise level are smaller in a shielded courtyard than in a corresponding directly exposed situation. Concerning the description of the noise source, it is concluded that the commonly used model with a single standard deviation for the A-weighted level needs to be improved to enable a more accurate prediction of time variations of third-octave band levels.
Forssén, J and Hornikx, M. (2008) Characteristics of road traffic noise level statistics for shielded areas. Proc. Euronoise, Paris, 2008.
For noise immission, it is of interest to study other noise level statistics besides the long-term equivalent levels and maximum levels. By further analysis of the time variations of the noise level, an improved description of the negative effects of the noise may be achieved, for instance concerning perceived annoyance. Here, noise level histograms, i.e. probability density functions of sound pressure levels, from controlled recordings have been investigated. This has been made for a situation of special interest, which is a courtyard shielded from a dominating road traffic noise source. It has been reported previously that many shielded urban areas show levels that are considerably higher than the equivalent level, described as an upward tail of the histogram, which is not a usual characteristic of directly exposed areas. From the analysis made here, it is shown that the upward tail, i.e. the higher levels, of the shielded area is caused by locally occurring, unshielded road traffic events. It is concluded that the upward tail as a common characteristic of shielded urban areas may well be due to locally occurring noise events, for instance due to local road traffic.
Forssén, J., & Ögren, M. (2002). Barrier noise-reduction in the presence of atmospheric turbulence: Measurements and numerical modelling. Applied Acoustics, 63(2), 173-187.
Atmospheric turbulence causes scattering of sound, which can reduce the performance of sound barriers. This is important to include in prediction models to get a correct picture of the sound reduction at higher frequencies. Here a prediction method is applied that uses the strengths of the wind and temperature turbulence to estimate the scattered power into the shadow zone of a barrier. The predictions are compared to full-scale measurements on a thick barrier, where both acoustic and meteorological data were recorded simultaneously under both calm and windy conditions. Comparison between the measurements and the predictions indicate that the method gives reasonably accurate results for mid to high frequencies and a slight overestimation at very high frequencies.
Gidlöf Gunnarsson, A., and Öhrström, E. (2005). Noise and general well-being in urban environments: The potential role of nearby natural areas. Life in the Urban Landscape, Göteborg 30 maj till 4 juni, 2005.
A growing body of literature indicates that contact with nature influence people’s health and psychological well-being both directly and by moderating processes. A questionnaire study was conducted in urban residential settings with high road-traffic noise exposure (LAeq,24h ³ 60 to 68 dB). Out of 500 subjects, 367 lived in dwellings with access to a quiet side (free field LAeq,24h < 45 dB; “noise/quiet”-condition) and 133 had no access to a quiet side (“noise/noise”-condition). Previous results show that a quiet side of the dwelling influence subject’s responses to noise. The present paper examines whether nearby green natural areas further affects various aspects of general well-being in these two noise-condition groups. The results show that very good availability to nearby green areas is important for resident’s general well-being and daily behavior by reducing noise annoyances and increasing usage of spaces outdoors. In the process of planning health-promoting urban environments, it is essential to strive for lower sound levels (LAeq,24h < 60 dB), to design “noise-free” sections indoors and outdoors, as well as to provide easy access to nearby natural areas that can offer a positive sound environment, relief from environmental stress, and opportunities for rest and relaxation.
Gidlöf Gunnarsson, A., and Öhrström, E. (2005). The influence of courtyard quality on annoyance and general well-being in noise-exposed urban residential areas. In: Inter-Noise 2005. Rio de Janeiro: Brazilian Acoustical Society (SOBRAC), Paper 1570. [Available on CD]
Noise has documented adverse health effects, however, psychological processes and moderating factors influence the relationship between noise and health outcomes. Research on restorative environments suggests that certain environments provide high quality restorative experiences that may act as moderators of adverse conditions. A questionnaire study was conducted in urban residential areas with road-traffic noise exposure between LAeq, 24h 58 to 68 dB at the most exposed façade. The dwellings had “quiet” indoor section/s and faced a “quiet” outdoor courtyard (LAeq, 24h < 45 dB). The present paper examines the physical environmental quality of the “quiet” courtyards (PEQC) and explores the effect of PEQC on health and well-being. Data were collected from 358 residents (18 to 75 years of age) and four groups were formed based on sound-level categories (58-62 and 63-68 dB) and PEQC classification (low and high). At both sound-level categories, the results indicated that high PEQC-classified “quiet” courtyards provided opportunities for rest and relaxation, which may have moderated the effects of noise with regard to less noise annoyance and noise-disturbed outdoor activities. However, due to high sound levels at the trafficked side of the dwelling, a “quiet” indoor section and a high PEQC-classified “quiet” courtyard could not counterbalance completely the adverse health effects of noise. Thus, 17 and 28 % were still noise annoyed at 58-62 and 63-68 dB, respectively.
Gidlöf Gunnarsson, A., Berglund, B., Haines, M., Nilsson, M.E., & Stansfeld, S.A. (2003). Psychological restoration in noise-exposed children. In R.G. de Jong, T. Houtgast, E.A.M. Franssen & W.F. Hofman (Eds.), Noise as a Public Health Problem. Schiedam, The Netherlands: Foundation ICBEN 2003, pp. 159-160.
Gidlöf Gunnarsson, A., Berglund, B., & Nilsson. M. E. (2003). Utilizing noise sensitivity in long-term and short-term noise annoyance model. In B. Berglund & E. Borg (Eds.), Fechner Day 2003. Stockholm: International Society for Psychophysics, pp. 103-108.
A soundscape field study was conducted in three urban residential areas, differently exposed to road-traffic noise. Based on questionnaire reports, noise sensitive and noise insensitive residents were identified. Subsamples of each class (n = 24+20) participated in walks involving six indoor and outdoor listening places in their home areas. Long-term noise annoyance (last 12 months) was registered in questionnaires and short-term annoyance in protocols of 30-s soundscape listening. Compared to noise insensitives, noise sensitives more often heard rod-traffic sounds, and were significantly more long-term noise annoyed but also somewhat more short-term noise annoyed. Noise sensitives’ long-term annoyance was not possible to predict from aggregated short-term noise annoyances referring to six listening places, indoors and outdoors. On the contrary, noise insensitives’ long-term annoyance was significantly predicted from the model including six short-term noise annoyances; the most outstanding predictor was “outdoors at the sidewalk of the noisy street”. The findings suggest that between-groups differences in long-term and short-term noise annoyances was dependent on where the soundscapes were heard, for instance, outdoors or indoors with closed or open window. Thus, contextual effects were found to be of great importance in soundscape evaluation.
Gidlöf-Gunnarsson, A., & Öhrström, E. (2007).Noise and well-being in urban residential environments: The potential role of perceived availability to nearby green areas. Landscape and Urban Planning. 83, 115-126.
A growing body of literature indicates that contact with nature influence people’s health and psychological well-being both directly and by moderating processes. A questionnaire study was conducted in urban residential settings with high road-traffic noise exposure (LAeq,24h = 60 to 68 dB). Out of 500 residents, 367 lived in dwellings with access to a quiet side (LAeq,24h ≤ 45 dB free field value; “noise/quiet”-condition) and 133 had no access to a quiet side (“noise/noise”-condition). The present paper examines whether perceived availability to nearby green areas affects various aspects of well-being in these two noise-condition groups. For both those with and without access to a quiet side, the results show that “better” availability to nearby green areas is important for their well-being and daily behavior by reducing long-term noise annoyances and prevalence of stress-related psychosocial symptoms, and by increasing the use of spaces outdoors. In the process of planning health-promoting urban environments, it is essential to provide easy access to nearby green areas that can offer relief from environmental stress and opportunities for rest and relaxation, to strive for lower sound levels from road traffic, as well as to design “noise-free” sections indoors and outdoors.
Gidlöf-Gunnarsson, A., Öhrström, E., Ögren, M.(2007). Noise annoyance and restoration in different courtyard settings: Laboratory experiments on audio-visual interactions. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 117. [Available on CD]
A typical noise abatement measure is to erect a noise barrier with an assumption of reducing sound levels from 7 up to10 dB. An alternative technique is to apply quiet asphalt, which typically reduces the level slightly less than a barrier does. However, evaluations of how abatement measures affects sound levels and the public experiences are seldom conducted. The present study examines noise annoyances before (2005) and after (2007) abatement measures in three quarters of a residential area located closed to a highly traffiked road. Sound levels year 2005 ranged between approx. LAeq24h 60 – 71 dB, 59 – 69 dB, and 58 – 66 dB in quarter A, B, and C, respectively. Type of abatement measures were application of quiet asphalt (2-Layered Porous Asphalt) (A) and 2-Layered Porous Asphalt combined with erection of an earth berm (B). In quarter C, residential buildings were located at a right angle towards the traffiked road and was therefore mainly affected by the quiet asphalt, but to a lesser degree. Traffic from a local road contributed here with noise. Sound levels in quarter A, B, and C were reduced in year 2007 by ≈ 5.5, 6.5, and 4 dB, respectively. Results indicate that quiet asphalt had no or a negative (increasing) effect on annoyances in quarter A and C, but the combination of quiet asphalt + earth berm significantly decreased annoyances in quarter B. High expectations about the effectiveness of abatement measures in creating a better sound environment indoors and outdoors may have influenced the results.
Haines, M.M., Stansfeld. S.A., Job, R.F.S., Berglund, B., & Head, J. (2001). Chronic aircraft noise exposure, stress responses, mental health and cognitive performance in school children. Psychological Medicine, 31, 265-277.
Previous research suggests that children are a high risk group vulnerable to the effects of chronic noise exposure. However, questions remain about the nature of the noise effects and the underlying causal mechanisms. This study addresses the effects of aircraft noise exposure on children around London Heathrow airport, in terms of stress responses, mental health and cognitive performance. The research also focuses on the underlying causal mechanisms contributing to the cognitive effects and potential confounding factors. The cognitive performance and health of 340 children aged 8-11 years attending four schools in high aircraft noise areas (16-hr outdoor Leq >66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16-hr outdoor Leq < 57 dBA). Mental health and cognitive tests were group administered to the children in the schools. Salivary cortisol was measured in a sub-sample of children. Chronic aircraft noise exposure was associated with higher levels of noise annoyance and poorer reading comprehension measured by standardised scales with adjustments for age, deprivation and main language spoken. Chronic aircraft noise was not associated with mental health problems and raised cortisol secretion. The association between aircraft noise exposure and reading comprehension could not be accounted for by the mediating role of annoyance, confounding by social class, deprivation, main language or acute noise exposure. These results suggest that chronic aircraft noise exposure is associated with impaired reading comprehension and high levels of noise annoyance but not mental health problems in children.
Haines, M.M., Stansfeld, S.A., Job, R.F.S., Berglund, B., & Head, J. (2001). A follow up study of the effects of chronic aircraft noise exposure on child stress responses and cognition. International Journal of Epidemiology, 30, 839-845
Children are a high risk group vulnerable to the effects of chronic aircraft noise exposure. This study examines the effects of aircraft noise exposure on children’s health and cognition around London Heathrow airport and tests sustained attention as an underlying mechanism of effects of noise on reading and examines the way children adapt to continued exposure to aircraft noise. In this repeated measures epidemiological field study, the cognitive performance and health of 275 children aged 8-11 years attending four schools in high aircraft noise areas (16-hr outdoor Leq>66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16-hr outdoor Leq<57 dBA). The children first examined at baseline were examined after a period of one year at follow-up. Health questionnaires and cognitive tests were group administered to the children in the schools. At follow-up chronic aircraft noise exposure was associated with higher levels of annoyance and perceived stress, poorer reading comprehension and sustained attention, measured by standardised scales after adjustment for age, social deprivation and main language spoken. These results do not support the sustained attention hypothesis previously used to account for the effects of noise on cognition in children. The reading and annoyance effects do not habituate over a one year period and do not provide strong evidence of adaptation.
Hornikx, M. (2004). Towards a parabolic equation for modelling urban sound propagation. In: Proc. 11th Long Range Sound Propagation Symposium. Fairlee, Vermont, USA: University of Mississippi, National Center for Physical Acoustics, June 2004.
Sound waves propagating in urban environments are diffracted and reflected by obstacles and scattered and refracted by the moving atmosphere. A study to the influence of the atmospheric effects on these sound paths is valuable in obtaining knowledge about its contribution to sound pressure levels in urban areas. A wave propagation model that can handle complex atmospheric effects is the parabolic equation (PE) model. This model has been used in various atmospheric acoustics problems, mainly dealing with problems at low propagation angles and horizontal wind components only. A main limitation of the PE is the accurate modeling at high propagation angles in moving media. To extend the range of applicability of the PE to urban areas, a two-dimensional PE has been constructed which enables sound propagation under these high angles. In this model, both mean and turbulent medium velocity components have been treated as a vector and a rational- quadratic approximation of the square root operator has been used. Computation results show the capabilities of the model in a moving medium up to high angles. Application of the PE in city canyon calculations show pronounced deviations from correct results that can mainly be attributed to the used Kirchhoff approximations.
Hornikx, M. (2006) Sound propagation to two-dimensional shielded urban areas – A numerical and scale model study of façade treatments. Göteborg, Sweden: Department of Applied Acoustics, Chalmers, Licentiate Thesis.
Annoyance and adverse health effects caused by road traffic noise is a major environmental problem in Swedish and European cities. The strategy of offering citizens areas shielded from direct road traffic noise is an approach researchers from different fields work with. From the acoustical point of view, knowledge of the sound propagation from road traffic noise sources toward these shielded areas is a necessity to be able to create quieter urban areas, which can be regarded as healthy with respect to noise. The geometry of parallel urban street canyons has been used throughout in this work. Road traffic is present in one of the canyons. Two numerical models have been further developed in order to predict the sound pressure level in the shielded canyon due to road traffic noise sources. For the first model, the parabolic equation method (PE), limitations have been relaxed to model sound propagation for urban street canyons and a moving medium with mean and turbulent wind speed components. The model has been validated by various other models and results from measurements. A second model, the 2.5-dimensional Equivalent Sources Method (2.5-D ESM) is an extension of the existing 2-D ESM. The 2.5-D ESM allows for a point source in a 3-D environment in which the geometry is invariant in one direction. The transform from the 2-D ESM to the 2.5-D ESM has been shown to be successful. Besides the numerical models, a 1 to 40 scale model study was executed, with various façade treatments for the 2.5-D geometry, yet also for a closed courtyard situation. Results were successfully used to validate the 2.5-D ESM. Concerning the properties of the sound field, the influence of façade reflections is concluded to govern the sound pressure level and time decay properties of the shielded canyon. The impulse response at the shielded canyon is characterized by a rise time. Levels and decay times are concluded to be rather constant over the canyon length. To reduce the sound pressure level at the shielded canyon, horizontally oriented diffusion façade treatments were shown to be more efficient than vertically oriented ones. For two real life shielded courtyards in the city of Gothenburg, noise abatement schemes consisting of changing the absorption properties of the façades and ground material were evaluated using the 2.5-D ESM. A partial façade change to an absorption coefficient of 0.6 was shown to lead to an average loss of 2-4 dB(A) for the shielded canyon receiver points. Façade treatments as well as a change to a softer ground both resulted in larger losses for receiver positions close to ground.
Hornikx, M., & Forssén, J. (2006). Scale model measurements and numerical modelling for directly exposed and shielded urban street canyons. In: Proc. Joint Baltic-Nordic Acoustics Meeting (BNAM 2006), Gothenburg, Sweden: The Swedish Acoustical Society.
An extensive scale model study of two parallel urban street canyons was executed to investigate sound pressure levels at the directly exposed and shielded canyon. Of interest is sound propagation due to road traffic noise in cities. At the shielded side, only contributions from sound waves diffracted over the roof are included. Existing prediction methods for shielded street canyons, like the equivalent sources method, are based on a two-dimensional wave equation. The results of the scale model measurements were used to validate the equivalent sources method. The equivalent sources method results were therefore transformed to a point source solution. The agreement between measurements and calculations is satisfactory. Measurements were also made for situations were the transformed equivalent sources solution is not valid: a courtyard situation and a situation with vertically oriented diffusion elements. Results show that horizontally oriented diffusion objects are more effective to reduce levels at the shielded side than vertically oriented diffusion elements. The level at the shielded side is rather constant over the length of the street compared with the levels at the directly exposed side, and the energy time curves at the shielded side are characterized by a rise time.
Hornikx, M., & Forssén, J. (2006) Sound abatement schemes for real life shielded urban street canyons. In: Proc. 12th International Symposium on Long Range Sound Propagation. New Orleans, LA: University of Mississippi, National Center for Physical Acoustics, October 2006.
Urban areas shielded from direct road traffic noise are of a high value with respect to effects of noise on health and well-being effects. Since many distant sources contribute to the sound pressure levels at these areas, like inner yards, reducing the levels could be necessary. In this paper, two such shielded environments in Gothenburg have been selected for a numerical in-vestigation of noise abatement schemes. Thereby, it is of importance that a realistic source has been used and that the modeled reference situations are close to the selected environments. The study is executed using a wave based numerical model for parallel street canyons, the 2.5 di- mensional Equivalent Sources Method. In this preliminary study, façade absorption treatments and a change of the ground impedance at the shielded sides have been investigated. As a result, a realistic change of façade absorption coefficients can lead to a reduction of 5 dB(A), and a change of the ground impedance from that of asphalt to grass to a reduction of 3 dB(A). The reduction is largest for the lowest receiver positions in the shielded canyon. When the domi- nating source is located in a street canyon, absorption treatments in the street canyon are more effective than in the shielded canyon for receivers at a higher position than the source.
Hornikx, M. and Forssén, J. (2007) The 2.5-dimensional equivalent sources method for directly exposed and shielded urban canyons. J. Acoust. Soc. Am. Vol. 122, No. 5.
When a domain in outdoor acoustics is invariant in one direction, an inverse Fourier transform can be used to transform solutions of the 2-dimensional Helmholtz equation to a solution of the 3-dimensional Helmholtz equation for arbitrary source and observer positions, thereby reducing the computational costs. This previously published approach [D. Duhamel, J. Sound Vib. 197, 547-571 (1996)] is called a 2.5-dimensional method and has here been extended to the urban geometry of parallel canyons, thereby using the equivalent sources method to generate the 2-dimensional solutions. No atmospheric effects are considered. To keep the error arising from the transform small, 2-dimensional solutions with a very fine frequency resolution are necessary due to the multiple reflections in the canyons. Using the transform, the solution for an incoherent line source can be obtained much more efficiently than by using the 3-dimensional solution. It is shown that the use of a coherent line source for shielded urban canyon observer positions leads mostly to an over-prediction of levels and can yield erroneous results for noise abatement schemes. Moreover, the importance of multiple façade reflections in shielded urban areas is emphasized by vehicle pass-by calculations, where cases with absorptive and diffusive surfaces have been modeled.
Hornikx, M. and Forssén, J. A scale model study of parallel urban canyons. (Accepted for publication in Acta Acustica united with Acustica.)
Shielded urban areas are of importance regarding urban citizens’ annoyance and adverse health effects related to road traffic noise. This work extends the existing knowledge of sound propagation to such areas by a scale model study, rather than by model calculations. The scale model study was executed for two parallel ur- ban canyons at a 1 to 40 scale, with a point source located in one canyon. Cases with acoustically hard façades and absorption and diffusion façade treatments were investigated. To correct for excess air attenuation of the measurements, a wavelet- based method has been applied. The measurement results in the shielded canyon show that, in contrast to the directly exposed street canyon, the levels and the decay times are quite constant over the length of the canyon. The energy-time curve in the shielded canyon is characterized by a rise time, which can be related to the sound pressure level. The rise times and decays can be explained by separate reflection, diffraction and diffusion processes. A closed courtyard situation enlarges the level difference between acoustically hard façades and applied façade absorption or dif- fusion treatments at both the directly exposed and shielded side. A comparison between measurements with two different diffusion mechanisms, horizontal and vertical diffusion, reveals that vertical diffusion yields lower levels at the shielded side compared to horizontal diffusion for the investigated situations.
Hornikx, M. and Forssén, J. (2007) Improving the shielding of road traffic noise in courtyards: treatments with vertical and horizontal screens. Proc. ICA, Madrid, Spain 2007.
Closed courtyards in city centres can offer the people living there a place of health and wellbeing regarding the adverse effects of road traffic noise. Due to combined effects of the contribution of many distant sources and multiple reflections in the courtyards, the equivalent sound levels might exceed the desired level regarding health and well-being. In this numerical study, the effect of applying vertical and horizontal screens for two courtyards modelled from real situations has been investigated for an incoherent line source outside the courtyards, where the courtyards have been modelled as canyons. Screens at the top of the roof reduce the level for all frequencies and observer positions in the courtyard by 4-5 dB. Horizontal screens applied to the façades, like walkways, also reduce levels evenly over the frequency. Their effect is largest for observer positions low in the canyon. Absorption below the walkways increases the reduction significantly, yet most for the lower observer positions and lower frequencies. The reduction for lower observer positions due to 1 m wide walkways with absorption amounts to 5 dB(A).
Hornikx, M. and Forssén, J. (2007) Improving the shielding of road traffic noise in courtyards: absorption treatments. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 118. [Available on CD]
Access to closed courtyards in city centres can offer the people living there a place of health and well-being regarding the adverse effects of road traffic noise. Due to combined effects of the contribution of many distant sources and multiple façade reflections in the courtyards, the equivalent sound levels might exceed 45 dB(A), a level desired regarding health and well-being. In this numerical study, the effect of adding absorption material for two courtyards modelled from real situations has been investigated for an incoherent line source outside the courtyards, modelled as canyons. The position and absorption coefficient of the applied absorption material have been varied. It can be concluded that façade absorption material is most effective when applied in the upper part of the façades. Also, it is shown that absorption material distributed over both façades gives a larger reduction than when concentrated to one façade only. The reduction by adding absorption is largest for observer positions low in the canyon. By applying absorption treatments, low frequencies can be reduced more effectively than high frequencies.
Hornikx, M. and Forssén, J. (2007) The 2.5-dimensional equivalent sources method for directly exposed and shielded urban canyons. Journal of the Acoustical Society of America, 122(5), 2532–2541.
When a domain in outdoor acoustics is invariant in one direction, an inverse Fourier transform can be used to transform solutions of the 2-dimensional Helmholtz equation to a solution of the 3-dimensional Helmholtz equation for arbitrary source and observer positions, thereby reducing the computational costs. This previously published approach [D. Duhamel, J. Sound Vib. 197, 547-571 (1996)] is called a 2.5-dimensional method and has here been extended to the urban geometry of parallel canyons, thereby using the equivalent sources method to generate the 2-dimensional solutions. No atmospheric effects are considered. To keep the error arising from the transform small, 2-dimensional solutions with a very fine frequency resolution are necessary due to the multiple reflections in the canyons. Using the transform, the solution for an incoherent line source can be obtained much more efficiently than by using the 3-dimensional solution. It is shown that the use of a coherent line source for shielded urban canyon observer positions leads mostly to an over-prediction of levels and can yield erroneous results for noise abatement schemes. Moreover, the importance of multiple façade reflections in shielded urban areas is emphasized by vehicle pass-by calculations, where cases with absorptive and diffusive surfaces have been modelled.
Hornikx, M. and Forssén, J. (2008). A scale model study of parallel urban canyons. Acta Acustica united with Acustica, 94(2), 265-281.
Shielded urban areas are of importance regarding urban citizens’ annoyance and adverse health effects related to road traffic noise. This work extends the existing knowledge of sound propagation to such areas by a scale model study, rather than by model calculations. The scale model study was executed for two parallel ur- ban canyons at a 1 to 40 scale, with a point source located in one canyon. Cases with acoustically hard façades and absorption and diffusion façade treatments were investigated. To correct for excess air attenuation of the measurements, a wavelet- based method has been applied. The measurement results in the shielded canyon show that, in contrast to the directly exposed street canyon, the levels and the decay times are quite constant over the length of the canyon. The energy-time curve in the shielded canyon is characterized by a rise time, which can be related to the sound pressure level. The rise times and decays can be explained by separate reflection, diffraction and diffusion processes. A closed courtyard situation enlarges the level difference between acoustically hard façades and applied façade absorption or dif- fusion treatments at both the directly exposed and shielded side. A comparison between measurements with two different diffusion mechanisms, horizontal and vertical diffusion, reveals that vertical diffusion yields lower levels at the shielded side compared to horizontal diffusion for the investigated situations.
Hornikx, M. and Forssén, J. (2008). Noise abatement schemes for shielded canyons. (Accepted for publication in Applied Acoustics.)
Access to quiet areas in cities is important to avoid adverse health effects due to road traffic noise. Most urban areas which are or can become quiet (i.e. LA,eq < 45 dB) are shielded from direct road traffic noise. Many road traffic noise sources contribute to the level in these shielded areas by transfer paths over roof level, and noise abatement schemes may be necessary to make these areas quiet. Two real life shielded areas in Göteborg have been selected as reference cases for a numerical investigation of noise abatement schemes. Thereby, the selected areas are modeled as canyons with a road traffic noise source modelled outside the canyon by a finite incoherent line source, which is more realistic than both a coherent and an incoherent line source of infinite length. The equivalent sources method has been used for the calculation. For all studied treatments in the shielded canyon, the reductions are largest for the lower observer positions. Façade absorption is most effective when placed in the upper part of the canyon and can typically yield a reduction of 4 dB(A), and 1 m wide walkways with ceiling absorption 3 dB(A). These effects are most effective for narrower canyons. For the treatments at the canyon roof, reductions are independent of the canyon observer position and amount to 4 dB(A) for 1 m tall screen and 2 dB(A) for a grass saddle roof. Downward refractive conditions increase the levels for the lower observer positions and higher frequencies. Noise abatement schemes applied in the source canyon are more effective assuming that all influencing source canyons are treated.
Hornikx, M. and Waxler, R. (2008) An eigenfunction expansion method to efficiently evaluate spatial derivatives for media with discontinuous properties. Proc. Euronoise, Paris, 2008.
Pseudo-Spectral methods are often used as an alternative to the Finite Difference Time Domain (FDTD) method to model wave propagation in heterogeneous moving media. The FDTD method is robust and accurate but is numerically expensive. Pseudo-Spectral methods make use of the wavelike nature of the solution to obtain more efficient time-domain algorithms. The most straightforward of the Pseudo-Spectral methods is the Fourier method in which a spatial Fourier transform is used to evaluate the spatial derivatives in the wave equation. Whereas this method is accurate for a weakly heterogeneous moving medium, it degenerates for media with discontinuous properties. The eigenfunction expansion method presented here is a way to accurately and efficiently evaluate spatial derivatives in media with interfaces. As in the Fourier method, transforms may be calculated using FFT’s and spatial sampling is limited only by the Nyquist condition. The performance of the method is shown in a time-domain implementation for media with discontinuous density and sound speed.
Hornikx M., Forssén, J. & Kropp W. (2005). A scale model study of parallel urban street canyons. (Abstract only.) Journal of the Acoustical Society of America 117(4), Pt. 2, 2417.
The access to quiet areas in cities is of increasing importance. Recently, the equivalent sources method for a two dimensional situation of parallel urban street canyons has been developed. One canyon represents a busy road, whereas the other is one without traffic; the quiet side. With the model, the transfer function between the two canyons can be calculated, as well as the influence of diffusion, absorption, and atmospheric turbulence on the transfer function. A scale model study of two parallel canyons has now been executed. A scale of 1:40 has been chosen and the maximum length sequence technique has been applied using the MLSSA system. Results of the scale model study have been compared to calculations with the equivalent sources method. The difference between a two-dimensional and a three-dimensional quiet side, between a coherent and an incoherent line source and the influence of absorption and diffusion has been investigated. The scale model study also gives insight in the evolution of the sound field in the time domain. [Work supported by the Swedish Foundation for Strategic Environmental Research (MISTRA).]
Hornikx, M., Forssén, J., & Kropp, W. (2006). Scale model measurements and numerical modelling for directly exposed and shielded urban street canyons. In J. Hyurynen & R. Pääkönen (Eds.), EuroNoise 2006: Advanced Solutions for Noise Control. Tampere, Finland: European Acoustics Association, Paper SS20-236. [Avaliable on CD].
An extensive scale model study of two parallel urban street canyons was executed to investigate sound pressure levels at the directly exposed and shielded canyon. Of interest is sound propagation due to road traffic noise in cities. At the shielded side, only contributions from sound waves diffracted over the roof are included. Existing prediction methods for shielded street canyons, like the equivalent sources method, are based on a two-dimensional wave equation. The results of the scale model measurements were used to validate the equivalent sources method. The equivalent sources method results were therefore transformed to a point source solution. The agreement between measurements and calculations is satisfactory. Measurements were also made for situations were the transformed equivalent sources solution is not valid: a courtyard situation and a situation with vertically oriented diffusion elements. Results show that horizontally oriented diffusion objects are more effective to reduce levels at the shielded side than vertically oriented diffusion elements. The level at the shielded side was rather constant over the length of the street compared with the levels at the directly exposed side, and the energy time curves at the shielded side are characterized by a rise time.
van Kamp, I., Nilsson, M.E., van Kempen, E., Stellato, R.K., Lopez-Barrio, I., Davies, H., & Stansfeld, S.A. (2004). Combined effects of aircraft noise and road-traffic noise on annoyance: the RANCH study. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 398. [Available on CD]
One of the objectives of the EU 5th Framework project RANCH (Road traffic and aircraft noise exposure and children’s cognition and health) is to provide knowledge on exposure-response relationships in children between chronic noise exposure and physical and psychological health outcomes including annoyance. Data collected in three large field surveys among school children enabled us to study the exposure-response relations in greater detail than had been accomplished in previous studies. This paper describes annoyance responses of school children in relation to the combined exposure to road- and air-traffic noise during both day and evening (LAeq,7-23h). Data are derived from a questionnaire and tests administered to a sample of children aged 9-11 years visiting primary schools around London Heathrow Airport (N=1182), Amsterdam Schiphol Airport (N=737) and Madrid Airport Barajas (N=920). As part of a paper-and-pencil test battery, the children completed a questionnaire on perceived health, sleep quality, coping with noise, annoyance and noise interference with activities. The interaction of air and road traffic noise on source-specific annoyance, as well as total annoyance was analyzed. Combined exposures were calculated as multiplicative interactions. Results showed that the effects of aircraft noise on annoyance were greater in high road traffic noise situations. Similarly, high road traffic noise exposure had a larger effect upon annoyance in high aircraft noise exposure situations than in low aircraft noise exposure. These results only held for the separate annoyance questions (the air- and road traffic components separately) and not for total annoyance, supporting the so-called combined noise source paradox.
Kilhlman, T. (2000). Noise abatement in town planning. Conclusions. In D. Cassereau (Ed.), Inter Noise 2000. Bron, France: INRETS, vol. 2, pp. 1026-1029.
Kihlman, T. (2001). Quiet side and high facade insulation–means to solve the city noise problem. In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Netherland: The Nederlands Akoestisch Genootschap (NAG), vol. 2, pp. 1227-1236.
The common long-term goal for road traffic noise, Lden<55 dB cannot be reached for all dwellings neither in sprawled nor in compact cities during a foreseeable future. [1] Strategies to improve the situation then include the use of highly insulating facades and the exploitation of the spatial noise level variations.Even though many dwellings are exposed to Lden=65-70 dB, outdoor levels in the range 40-50 Lden are not rare in the cities: courtyards in European cities being the typical case. The EU draft directive on ambient noise includes the use of facade insulation and the protection of quietness. This session has the aim to present some of the scientific foundation for these measures and discuss their potentials. Questions to answer are: What are the effects on the annoyance and sleep disturbance when dwellings have good facade insulation and/or one noisy and one quiet side? To what extent do existing, noise exposed dwellings also have a quiet side? What are the potentials to increase – also at low cost - the access to quietness in the urban renewal process?
Kihlman, T. (2003). Develop the acoustic soundscape for less adverse health effects. In: Inter-Noise 2003. Jeju, Korea: The Korean Society for Noise and Vibration Engineering (KSNVE), Paper 900 [ISBN 89-952189-1-6 98060]. (Available on CD from KSNV, Seoulk Seocho-gu Soecho-dong 1598-3, Korea)
Goals for traffic noise immission have since long been expressed in terms of noise levels outside the most exposed facades. Even though these goals are compromises, the gap between common actual levels and these goals is often10 – 20 dB. This has led to an increasing interest for quietness; quiet recreation areas, quiet parks, “quiet facades”, etc. See e. g. [1]. This in its turn has led to studies of dose-response relationships, where the dose is expressed by more detailed data – the acoustic soundscape describing the exposure situation with its variations in time and space. See the research program, Soundscape for better health, www.soundscape.nu. With increasing knowledge of such dose-effect relations, the noise abatement can be directed towards such measures that decrease the effects in a more cost-effective way. The political goal should then, consequently, be expressed in the effects of the noise on people and its fulfilment adequately monitored. Dose-effect relationships have to be used to transform the political goals into operational measures to be used in city and traffic planning and city renewal.
Kihlman, T. (2004). Dose-response relations must be linked to the soundscape. In: ICA 2004. Tokyo, Japan: Acoustical Society of Japan, vol. IV, pp. 2625-2626.
In the research program Soundscape Support to Health (www.soundscape.nu) different adverse health effects have been studied for different city traffic noise situations. it is clear from the results that e.g., the annoyance is quite different depending upon whether or not the exposed persons have access to a quiet side of their dwelling. In developing strategies by which the adverse effects of the traffic noise might be decreased within a foreseeable future, it is essential to perform studies of community response to traffic noise so that possible technical measures to reduce the adverse effects can be evaluated. The exposure must be measured in much more detail than just the sound level outside the most exposed facade. Factors to consider include levels outside different part of the dwelling, windows insulation, access/distance to quiet outdoor places such as parks and recreation areas, etc.
Kihlman, T. Experiences of implementation of Soundscapes in Policies. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 120. [Available on CD]
Noise is difficult to manage from the political side. The reason is that there is no technological fix available on the source side and that the discrepancy between the existing situation and the desired one is so great. When discussing policy results, it is necessary to distinguish between the local level, the national public agency level (non-departmental public body), the national political level and the EU/international level. The results from our research program has strongly influenced the public agency level in Sweden, but less the national political level. Access to a ”quiet side” has become an important element in the planning when the noise level at the directly exposed side of dwellings does not fulfill the national guideline value, which is LAeq,24h free field < 55 dB. A clear definition of the concept has also been set (Leq24h<45 dB free field with the relation +3dB 2 m from facade wall and +6dB at the facade wall). From the agency level, revised formulations of the national environmental goals have also been proposed as a result of our research results. On the EU level, in the Directive 2002/49/EC, (END), the concepts quiet areas and ”quiet facades” have been introduced and should be part of the national reports to the Commission. Also, results from our research have been important in position papers from the working groups linked to END.
Kihlman, T., & AbuKadher, S. (2001). Long-term noise abatement planning–case studies in Göteborg, Sweden. In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Netherland: The Nederlands Akoestisch Genootschap (NAG), vol. 3, pp. 1203-1208.
The goal of the project is to develop a long–term noise abatement plan for the urban area of Göteborg. The work is part of a research program and its special focus is to investigate the idea to systematically use quiet areas and quiet sides of buildings. To what extent can access to quiet areas and quiet sides of buildings be parts of a program to decrease the health effects of the city noise. This paper is devoted only to the possibilities to create quiet spots. The health effects are studied in other projects within the program. Outgoing from present noise conditions the paper shows through some case studies that lowered exposition can be combined with a compacting of the city, but that there are problems with regard to e.g. architecture as well as other noise sources than the traffic.
Kihlman, T. & Kropp, W. (2001). City traffic noise–A local or global problem? Noise Control Engine-ering Journal, 49(4), 165-169.
Traffic density data for 45 cities around the world show that the traffic work per unit urban area and time is so equal that the average traffic noise emission per unit urban area lies within 3 or maximum 5 dB for these 45 cities. The traffic noise problem in different cities therefore shows great similarities. From this starting point a couple of European cities are analyzed with respect to the potential to reach certain longterm goals by local noise abatement plans. The means in such plans can be the use of noise barriers, strict noise emission requirements on the vehicles for public transportation (use of best known technology), increased use of public transportation, traffic changes, traffic calming, use of special road surfaces, compact city planning, etc. The paper shows that such means either demand means that are not reasonable in a democracy or long-term community noise limits much above what is typical for northern Europe today.
Kilhlman, T., Kropp, W., Öhrström, E., & Berglund, B. (2001). Soundscape support to health. A cross-disciplinary research program. In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Netherlands: Nederlands Akoestisch Genootschap, vol. 3, pp, 1237-1242.
The Swedish research programme Soundscape Support to Health aims at developing methods and models and providing tools for predicting and optimising acoustic soundscapes in connection with traffic and city planning, including the production of new dwellings and rebuilding of dwellings in noise polluted areas, with respect to effects on health. The programme started late in 1999 and runs over 4 years. It is a cross disciplinary programme between three departments at three universities. It consists of 8 projects including studies of annoyance, sleep disturbance, soundscape perception, sound propagation in cities and finally town planning with regard to noise. It is financed by the Foundation for Strategic Environmental Research in Sweden.
Kihlman, T., Ögren, M., & Kropp, W. (2002). Prediction of urban traffic noise in shielded courtyards. In A. Selamet, R. Singh, & G.C. Maling (Eds.), Inter Noise 2002. Dearborn, MI. USA: International Institute of Noise Control Engineering (I-INCE), Paper N 483. (Available on CD).
Predicting traffic noise levels outside buildings facing busy streets normally give results which deviate from the true value by at most a few dB. These levels typically lie in the range Laeq,24h = 60 – 75 dB. In European cities we often have (closed) courtyards which are rather well shielded from direct traffic noise exposure. The result is a soundscape of the city that shows marked variations which may be systematically exploited as a partial solution to reduce the adverse effects of noise. However, predictions of the noise levels in the courtyards using well established propagation models often underestimate the true noise levels by 10 – 15 dB. (The courtyards are much noisier than calculated.) Examples of measurements compared to calculations using traditional prediction models will be shown. The reason for the underestimation of the levels seems to be that most traditional models only take nearby sources into account, whereas the levels in shielded locations to a high degree are influenced by all the sources in a large area.
Kihlman, T, Öhrström, E., & Skånberg, A. (2002). Adverse health effects and the value of access to quietness in residential areas. In A. Selamet, R. Singh & G.C. Maling (Eds.), Inter Noise 2002. Dearborn, MI, USA: International Institute of Noise Control Engineering (I-INCE), Paper 484. (Available on CD)
A 4-year research program, Soundscape Support to Health, aims to obtain knowledge of how various adverse health effects and behaviors are related to noise exposures from road traffic noise in residential areas, with and without access to a quite side of the dwelling, and to use this knowledge in action plans against noise in cities [1]. Adverse health effects are evaluated by questionnaires in five study sites in Swedish cities with different noise exposure levels. This paper presents preliminary results from two study sites. In the studied areas, some dwellings have one noisy and one quiet side; some dwellings have no quiet side. The results show that the access to a quiet side in the dwelling has a clear positive effect; less annoyance, less sleep disturbance, bedroom windows can be open in nighttime, balconies facing a quiet side are more often used than balconies facing a noisy side.
Kilhman, T., & Schulte-Fortkamp, B. (2004). Soundscapes. Conclusions concerning results and research needs. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 194. [Available on CD]
The paper is based upon abstracts for the papers in the two sessions PA2 and PA3 on Soundscapes and will describe the broad variety of approaches, present selected examples of current soundscape research and outline the utility of the soundscape approach for the assessment of noise annoyance. Soundscape has become a significant topic in the field of community noise. The methodological approach takes into account the dependency on "acoustic colouration" from the larger environment (geography, climate, wind, water, people, buildings, animals etc.) sound sources create "meanings" to the exposed and block or enable human activities, thoughts, feelings. Therefore, soundscape assessment is based on both, the acoustical but also on other dimensions such as visual, aesthetic, geographic, social and cultural modalities in the context of human activity in space and time. (Lercher, Schulte-Fortkamp 2003)
Kihlman, T., Öhrström, E., & Berglund, B. (2004). Monitoring the long-term development of the community noise situation. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 623. [Available on CD]
The community noise situation changes slowly and the goal – a community without noise disturbances – is very remote. It is, however, important to monitor if the development goes in direction of increasing or decreasing problems. The studies in the program Soundscape Support to Health have given some quantitative data on how differences in the acoustic soundscape can influence residents’ perceived soundscapes as well as their annoyance and sleep disturbance. It is insufficient to look only at the sound pressure levels outside the most exposed facades. Cost effective measures to reduce the adverse effects and promote positive effects can be retrieved from soundscape studies. monitoring the development by sufficiently accurate acoustic measurements in a sufficient number of points is very expensive. A better way is to try to measure the adverse effects of the community noise. Annoyance is one adverse candidate variable that can be measured at reasonable cost. A first study of this kind has been performed in Sweden through telephone interviews directly to 2000 persons. The results are promising.
Klaeboe, R., Öhrström, E., Turunen-Riis, I.H., Bendtsen, H., & Nykänen, H. (2003). Vibrations in dwellings from road and rail traffic–Part III: Towards a common methodology for socio-vibrational surveys. Applied Acoustics, 64, 111-120.
While a range of international standards defining noise, vibration and other physical environmental measures have been established, common methodologies for measuring people's reactions to these same environmental effects are still in their infancy. This reduces the comparability of prevalence statistics and exposure–effect relationships developed by different researchers. The public authorities are served incompatible or seemingly conflicting information from different surveys when deciding on appropriate guidelines and limits. Drawing on experiences with the 1998 Norwegian Socio-vibrational Survey and a Swedish socio-acoustic survey supplemented with vibration measures, a new Nordtest Method: NT ACOU 106 Acoustics––Assessment of annoyance by vibrations in dwellings from road and rail traffic has been defined. The method describes sampling requirements, and proposes a mandatory verbal 5-point categorical annoyance scale and an optional 11-point numerical annoyance scale, both with lower anchoring point "Do not notice". A survey data output format is specified to allow researchers to pool data from different surveys.
Kropp, W., & Bérillon, J. (2000). A theoretical model to consider the influence of absorbing surfaces inside the cavity of balconies. Acta Acustica united with Acustica, 2000, 86, 485-495.
A theoretical model is developed to predict the sound field inside non-rigid cavities in the low and middle frequencies. The main idea is to use the Green’s function for rigid walls and replace the non-rigid areas by monopole sources, which have to fulfil the prescribed boundary conditions. Only a locally reacting impedance is considered. The model is applied in the case of balconies on building facades where parts of the balcony walls are covered by absorber material. The model shows good agreement with measurements. The reduction of the sound pressure in front of the window in the balcony is studied for different absorber locations inside the cavity of the balcony. Best results are achieved when treating the ceiling and the rear wall of the balcony. With this absorber configuration, an insertion loss between 4 and 7 dB can be expected inside a room behind the balcony when the window to the balcony is open. The model can be helpful to improve the insertion loss of balconies below 1 kHz and to optimise the use of absorbing material. It can also be applied to the more general problems dealing with the sound field in cavities where parts of the boundaries are non-rigid.
Kropp, W., Forssén, J., Ögren, M., & Thorsson, P. (2004). The failure of traditional traffic noise control for quiet areas. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 518. [Available on CD]
One can consider the acoustic soundscape as consisting of two parts the direct acoustic soundscape and the diffuse acoustic soundscape. This fact has important consequences when attempting to change the acoustic soundscapes. The traditional approach to control traffic noise by means of noise barriers or change of traffic distribution is only valid for the areas directly exposed from sources (direct acoustic soundscape). These areas will experience a certain decrease of sound pressure levels when applying these noise control measures. However there will be a lower limit for reduction due to the presence of a diffuse acoustic soundscape. To control/modify such a diffuse acoustic soundscape has been shown very difficult by traditional means of noise control. Main characteristic of diffuse acoustic soundscapes is the presence of a multitude of sources, distributed over a wide area contributing evenly to the acoustic soundscape in a certain areas. Screening will only lead to a redistribution of sound, however consequences of such a redistribution will not be recognised in a diffuse sound field. Absorption has been identified as a main parameter to control diffuse acoustic soundscapes. Reducing sound pressure levels in shielded areas such as inner-yards can only be achieved by adding acoustically absorbing areas along the transfer path between source and receiver, but especially inside the inner-yard. Redistribution of traffic flow has been shown to have a tremendous effect on the directly exposed side, but only a small effect in shielded areas.
Matheson, M., Clark, C., Stansfeld, S.A., Berglund, B., Öhrström, E., Fischer, P., & Lopez Barrio, I. (2003). The effects of road traffic and aircraft noise exposure on children’s cognition and health: The RANCH project. In G. Brambilla, C. Ianbiello & L. Maffei (Eds.), EURONOISE 2003. Rome, Italy: Italian Association of Acoustics (AIA). (Avaliable on CD, ISBN: 88-88942-00-9)
The RANCH project (Road traffic and aircraft noise exposure and children’s cognition and health: exposure-effect relationships and combined effects) aims to extend the existing knowledge base on the effects of combinations of aircraft noise and road traffic noise. Cross sectional field studies have been carried out in the UK, Spain and the Netherlands. In each of these studies children have completed a battery of cognitive tests in order to assess the effects of chronic noise exposure on reading comprehension, long-term episodic memory (recall and recognition) working memory, prospective memory and sustained attention. All children also completed a questionnaire which included questions about the children’s attitudes to noise and perceived health. Blood pressure was measured in a sub-sample. In order to assess dose-response relationships the sample has been selected according to a matrix having four levels of aircraft noise and road traffic noise as well as combinations of these sources.
Nilsson, M.E. Loudness integration of simultaneous and successive traffic sounds. Archives of the Center for Sensory Research, 2001, 6(3), 105-117.
The purpose of the present experiment was to explore underlying principles in total loudness judgments of combined traffic sounds. Two singular traffic sounds at various levels were presented successively or simultaneously in combination with an ambient sound of constant level and duration. Nine participants scaled these combined sounds with regard to total loudness, utilizing the method of free-number magnitude estimation. Systematic individual differences were found for the total loudness of successive traffic sounds. For six participants, scales of total loudness were inconsistent with a model of arithmetic summation of traffic sound loudnesses; three participants conformed with the arithmetic summation model. For all participants, total loudness of simultaneous sounds was largely determined by the loudest sound in the combination. The temporal pattern of the combined sounds influenced total loudness. In general, two traffic sounds were assessed as louder when presented successively than when presented simultaneously.
Nilsson, M.E. Perception of traffic sounds in combination. Archives of the Center for Sensory Research, 2001, 6(3). (Doctoral Dissertation)
The main objective of this thesis is to explore the relationship between total and source-specific loudness of combined traffic sounds. For this purpose, sound identification and loudness of singular and combined road traffic, aircraft, and train sounds were assessed in psychoacoustical experiments. It was found that the traffic sounds were sometimes misidentified with respect to source even when presented alone. As a rule, easily identifiable traffic sounds remained easy to identify when heard simultaneously in combination although their source-specific loudness was partially masked, when the combination involved another equally loud or louder traffic sound. For the first time, the relationship was explored between total loudness (Ytot|ab) and source-specific loudness of traffic sounds heard within combined sound (Ya|ab,Yb|ab). For this purpose, a general loudness integration model was utilized: Ytot|ab = ( Yna|ab + Ynb|ab)1/n, in which different values of the constant n define arithmetic summation (n = 1), Euclidean summation (n = 2), and the strongest component principle (n = ∞). For simultaneously presented traffic sounds, empirically determined n-values were found to range from 2.5 to 2.9. Corresponding n-values for source-specific loudness of traffic sounds heard alone (Ya|a,Yb|b) ranged from 4.1 to 4.2. Thus, total loudness of simultaneous traffic sounds was less than the arithmetic sum of source-specific loudnesses (heard within combined sound or alone) but greater than the maximum source-specific loudness. Conversely, for traffic sounds presented partially or completely separated in time, source-specific loudness was sometimes greater than total loudness. In fact, such “compromise” outcomes were mainly observed for unequally loud and time-separated sounds. This finding agrees with the idea that total loudness was “averaged” over the total duration of the combined and time-separated sound components whereas source-specific loudness of the louder (or softer) sound component was only “averaged” over the partial time period during which it was heard. Although total loudness of completely time-separated traffic sounds was found to adhere to the general loudness integration model, individual differences in assessment strategy gave estimates corresponding to a value of the constant n clearly greater than 1 for some participants and close to 1 (arithmetic summation) for others. Based on theoretical and empirical explications, this thesis concludes that a perceptual model for total loudness of combined traffic sounds should account for (a) masking of source-specific loudness, (b) the loudness integration principle, (c) perceptual integration time of source-specific loudness, and (d) individual differences in loudness assessment strategy.
Nilsson, M.E. (2005). A method for stimulus selection in environmental psychoacoustics. Archives of Acoustics, 30(4), 169-172.
In environmental psychoacoustics, experimental sounds are taken from recordings of real-life situations. This makes stimulus selection an important element of experimental design. For example, the sound level of road-traffic noise close to a major road may vary considerably depending on the number of vehicles that passes by. Thus, a psychoacoustical evaluation of the loudness or annoyance of the road-traffic noise would depend on which samples of the noise were presented in a listening experiment. Therefore, a method was developed for representative selection of experimental sounds from recordings in real-life situations. The method has been applied in research on auditory change caused by noise mitigation and in research on psychophysical relationships for loudness of road-traffic noise. It is argued that for many psychoacoustical problems, the ecological validity gained by representative selection outweighs the loss in internal validity caused by the reduced control of specific acoustical variables of the experimental sounds.
Nilsson, M.E. (2006). Traffic noise is a threat to outdoor recreation in urban areas. In Abstract Guide of the 26th International Congress in Applied Psychology. Athens: International Association of Applied Psychology, 2006, Abstract S125.4.
Current noise policy focuses on reducing high levels of community noise in dwellings, primarily with measures designed to reduce indoor levels. For example, one of Sweden’s environmental objectives is to reduce the number of persons highly exposed to traffic noise in dwellings by 5 % from 1998 to 2010. In the same period, car use is expected to increase with 29 %. This development is a threat to outdoor recreation in urban areas, because there is a real danger that in striving to reduce residential noise exposure, the sound environment in non-residential areas will be sacrificed. Unfortunately, guideline values for noise exposure in such areas, e.g., urban parks and green open spaces, are missing, mainly due to lack of knowledge on what makes a sound environment pleasant and restorative. Existing guideline values for residential areas are not relevant, because they are only intended for limiting negative effects of noise, such as annoyance and sleep disturbance, not for creating positive sound environments. This paper presents results from recent research on positive sound environments, and discusses the potential implications for noise policy.
Nilsson, M.E. (2007). A-weighted sound pressure level as an indicator of short-term loudness or annoyance of road-traffic sound. Journal of Sound and Vibration, 2007, 302 197-207.
Two listening experiments were conducted in order to determine whether A-weighting is a valid indicator of the perceived loudness or annoyance of road-traffic sound. Because A-weighting has been criticized for not properly integrating energy at low-frequencies, experimental road-traffic sounds were selected with a wide range in low-frequency content, assessed as the difference between C- and A-weighted sound levels (LC-A). In the first experiment, 30 listeners assessed the perceived loudness of the selected sounds. In the second experiment, another group of 31 listeners assessed the perceived annoyance of the same sounds. Sounds with high levels of LC-A were louder and more annoying than sounds with medium levels of LC-A, which in turn were louder and more annoying than sounds with low levels of LC-A, at similar A-weighted sound levels (LA). It was estimated that the change in perceived loudness or annoyance associated with a 1 dB change in LC-A would correspond to approximately a 0.4 dB change in LA. In contrast, sounds with similar Zwicker Loudness levels (LZ) were approximately equal in loudness and annoyance irrespective of their LC-A. Thus, LZ was found to be superior to LA as an indicator of short-term loudness and annoyance of road-traffic sounds with wide variation in low-frequency content.
Nilsson, M. E. (2007). Soundscape quality in urban open spaces. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 115 [Available on CD]
Guideline values for traffic-noise exposure in urban outdoor spaces are missing, mainly due to the lack of knowledge on the effect of noise on perceived soundscape quality. For this reason, questionnaire studies were conducted in several urban open spaces in the Stockholm area. The areas included a wide range of soundscapes, from highly traffic-noise exposed city parks to quiet suburban open spaces. Consistent relationships were found between measured overall sound levels and perceived soundscape quality. However, sound source identification was found to be a stronger predictor of soundscape quality than measured sound levels. Soundscape quality was negatively related to presence of technological sounds (e.g., road-traffic noise) and positively related to presence of nature sounds. These relationships remained also after controlling for overall measured sound level. Taken together, the results suggest, as a rule of thumb, that good soundscape quality in urban open spaces would require day-time traffic-noise exposure below 50 dBA. In situations with exposures between 50 and 55 dBA, soundscape design that promotes positive sounds from nature may be efficient in improving soundscapes. At higher levels, soundscape design has to be complemented with traditional noise control measures in order to achieve good soundscape quality.
Nilsson, M., Andéhn, M., & Lesna, P. Perceptual efficiency of road-traffic noise barriers. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 250 [Available on CD]
Noise barriers reduce the overall sound level of noise at the point of the receiver. In addition, the spectral composition and temporal variability of the noise is changed, and, thereby, the perceived character of the noise. This change in perceived character may have an additional effect on perceived annoyance, over and above the effect associated with the sound-level reduction achieved. For this reason, a perceptually valid evaluation of noise barriers requires knowledge on the extent to which the perceived character of noise is changed, and how this change influences perceived annoyance. This paper presents results from a listening experiment, which included recordings of road-traffic noise in the presence or absence of noise barriers. The results suggested that road-traffic noise behind barriers may be more annoying than expected from their A-weighted sound level. This effect was mainly caused by an increase in relative level of low-frequency content in the noise behind the barrier. Thus, the prediction of perceptual efficiency of noise barriers should not only be based on the expected reduction in A-weighted sound level, but also take into account the increase in relative level of low-frequency sound.
Nilsson, M.E., Axelsson, Ö., & Berglund, B. (2003). Children’s and adults’ perception of soundscapes at school. In G. Brambilla, C. Ianbiello & L. Maffei (Eds.), EURONOISE 2003. Rome, Italy: Italian Association of Acoustics (AIA), Paper ID: 394. [Available on CD, ISBN: 88-88942-00-9]
Methods were developed for measuring 40 children’s (10-11 years old) and their main carers’ perception of 34 soundscapes (10-s excerpts), which were selected from a large set of 45-min binaural recordings at schools around a major airport. Perceived loudness was master scaled, based on tape-measure matches of perceived length to perceived loudness of soundscapes and reference sounds. As expected, three emotional attribute scales (pleasantness, arousal, and control assessed by visual analogue scales) showed weaker relationships to sound level than the perceived loudness scale. Children’s and parents’ scales of perceived loudness and emotional attributes agreed well, although the children found the loudest outdoor sounds (aircraft sounds dominated) less loud than the parents. No difference was found between children attending schools with high aircraft noise exposures and children attending schools with low or no aircraft exposures. This suggests that prior contextual experience of noise does not affect soundscape perception. At equal sound levels (dBA), children and parents consider indoor soundscapes to be distinctly less pleasant than outdoor soundscapes. This supports the view that acoustical scales based on A-weighted sound level are inappropriate for comparative evaluations of indoor and outdoor soundscapes.
Nilsson, M.E., & Berglund, B. (2002). Perception of noise abatement efficiency: Evaluation of a noise barrier in an intervention study. Archives of the Center for Sensory Research, 7(1), 1-41.
The sound environment in a residential area was evaluated with the aid of a newly developed questionnaire, before and after a 2.25-m high noise barrier was built along a heavily trafficked road (approx. 19 000 vehicles/weekday). Another residential area along the same section of the road was used as a comparative control for the situation without remedial actions. The road-traffic noise exposure was approx. 65 dB LAeq,24h at facades closest to the road (approx. 22 m from the centre of the road) and approx. 55 dB at facades 50-75 m from the road. Noise exposure was reduced by at most 7 dB LAeq,24h for residents closest to the road and at most 2.5 dB for residents living approx. 100 m from the road, provided their buildings were fully shielded by the barrier. Some buildings which were located closest to the street entrances of the residential area got only 2 dB reduction in noise because they were not fully shielded by the barrier. For residents living within 100 m from the road, the noise barrier reduced the general annoyance, speech interference and sleep disturbance. The annoyance to exhausts, odors and dust from road traffic was also slightly reduced. The residents living more than 100 m from the road experienced no reduction in general annoyance or other studied variables. Although the noise barrier obviously improved the sound environment, serious noise problems continued to afflict the residents. For example, approx. 50 % of the residents living closest to the road were still moderately or highly annoyed by noise, approx. 38 % sometimes awoke in the morning to road-traffic noise, and approx. 83 % reported difficulties to comprehend speech outdoors in their gardens. The noise barrier did not to a greater extent improve the sound environment because the traffic noise exposure at facades were still high close to the road (58 dB LAeq,24h); most bedrooms were located on the second unshielded floor; annoying vibrations from road-traffic were unchanged, and those living close to road entrances to the area only had partial noise protection from the barrier.
Nilsson, M.E., & Berglund, B. (2001). Effects of noise from combinations of traffic sounds. Archives of the Center for Sensory Research, 6(1), 1-59.
A critical review is presented of models proposed for assessing annoyance of combined noises, especially road-traffic and train noise. The empirical support of the proposed models is also scrutinized. A General Perceptual Model (GPM) of total annoyance accommodates the great majority of proposed models of total annoyance of combined noise: Ytot|ij= (Yni|ij + Ynj|ij)1/n, where Ytot|ij stands for long-term total annoyance of the combined noise (e.g., road-traffic and train noise), Yi|ij stands for long-term source-specific annoyance of noise source i (e.g., road-traffic noise), Yj|ij stands for long-term source-specific annoyance of noise source j (e.g., train noise), and n is a constant. Source-specific annoyance may be assessed directly in existing multi-source situations. When using the GPM for prediction, its input variables have to be based on functions relating source-specific annoyance to predicted noise exposure. Such functions are typically based on data on source-specific annoyance in single-source situations. This means that “perceptual independence” has to be assumed, that is, a noise source in a single-source situation is assumed to be equally annoying as it is in a multi-source situation. The GPM with a constant of n = 2.5 is our recommended model for predicting total annoyance from source-specific annoyances. An illustration is given of how to apply the recommended model to the monetary costs of noise. The model postulates that a reduction of noise exposure from a single source may not be as cost effective in the multi-source situation as it is in the single-source situation. This means that a cost-effective reduction in noise exposure must involve a reduction of the noise exposure from both sources, provided both noises are distinctly annoying. A tentative procedure for considering other health effects of combined noise is proposed in which a safety factor is applied to the total annoyance of combined noise derived from the GPM. In selecting these safety factors for other health effects than annoyance, we have adhered to the guideline values recommended by the WHO in year 2000.
Nilsson, M.E., & Berglund, B. (2003). Evaluation of a road-traffic noise barrier: An intervention study. In A. Nilsson and H. Bodén (Eds.), Tenth International Congress on Sound and Vibration. Auburn, AL: International Institute of Acoustics and Vibration, vol. 7, pp. 3767-3774. (Available on CD)
Questionnaire studies were conducted before and 2 years after the construction of a 2.25-m high noise barrier along a heavily trafficked road (»19,000 vehicles/24h weekdays). Houses closest to the barrier received on average a sound-level reduction of 7.5 dB LDEN at the most exposed facades 22 m from center of road (from approx. 70.0 to 62.5 dB LDEN). The sound-level reduction decreased with distance to the road, and was negligible for buildings at more than 100 m distance. Correspondingly, the noise barrier reduced distinctly residents’ noise annoyance outdoors and indoors as well as improved speech communication outdoors. Only small improvements were observed indoors in speech communication and sleep disturbance. Despite the protecting barrier, serious noise problems prevailed. For instance, after the barrier was built, still, 46 % of the residents living closest to the main road (<25 m) often or very often experienced noise interference with speech communication outdoors in their gardens, and 20 % were often or very often awakened too early in the morning by road-traffic noise. These results confirm that reflecting noise barriers of conventional type insufficiently protect against exposures of high sound levels of road-traffic noise (>70 LDEN).
Nilsson, M.E., & Berglund, B. (2005). Assessment of outdoor soundscapes in quiet areas. Journal of Acoustical Society of America, 2005, 117(4) 2592.
Existing quiet outdoor areas should be preserved. Appropriate indicators and limit values are needed, which are grounded in knowledge on positive aspects of soundscapes, such as perceived pleasantness and psychological restoration. For this reason, a questionnaire study was conducted in four green areas close to a major city and in four city parks. Measured equivalent sound levels (LAeq. 15 min) ranged between 42 and 50 dBA in the green areas, and between 49 and 60 dBA in the city parks. Sounds from nature, such as bird song, completely dominated the soundscape in the green areas. The city-park soundscapes were more complex, containing sounds from nature, as well as technological sounds (e.g., traffic noise), and human sounds (e.g., human voices). In general, sounds from nature were perceived as pleasant, technical sounds as annoying, and human sounds as neutral. Between 84 and 100% of the visitors in the green areas assessed the soundscapes as good or very good. The corresponding percentages for the city parks were distinctly lower, between 52 and 65%. The results indicate that the equivalent sound level should be below 50 dBA in order to secure pleasant and restorative outdoor soundscapes in urban areas.
Nilsson, M.E., & Berglund, B. (2006). Noise annoyance and activity disturbance before and after the erection of a roadside noise barrier. Journal of the Acoustical Society of America, 119, 2178-2188.
Questionnaire studies were conducted in a residential area before and after the erection of a 2.25-m high noise barrier of conventional type along a heavily travelled road (19,600 vehicles/24h). The interval between studies was 2 years. Houses closest to the barrier received a sound-level redustion from approx. 70.0 to 62.5 dB Lden at the most exposed facade. The sound level reduction decreased with distance to the road, and was negligible for houses at more than 100 m distance. Up to this distance, the noise barrier reduced residents' noise annoyance outdoors and indoors as well as improved speech communication outdoors. Indoors, speech communication and sleep disturbance were slightly but non-significantly improved. Predictions of number of annoyed persons from published exposure-response curves (in Lden) agreed with the percentage of residents being annoyed when indoors, before and after the barrrier. Conversely, the percentage of residents being annoyed when outdoors clearly exceeded the predictions. These results suggest that these exposure-response curves may be used in predicting indoors situations, but they should not be applied in situations where outdoor annoyance is at focus.
Nilsson, M.E., & Berglund, B. (2006). Soundscape quality in suburban green areas and city parks. Acta Acustica united with Acustica, 2006, 92, 903-911.
According to guidelines proposed in Sweden, at least 80% of the visitors in quiet areas should perceive the sound environment as good. This was the starting point for a questionnaire study on “soundscape quality” in four suburban green areas and in four city parks. The soundscapes in the suburban areas were completely dominated by sounds from nature (e.g., bird song and sounds from water), whereas traffic noise was a main component of the city-park soundscapes. Measured equivalent sound levels (from all sources) ranged from 42 to 50 dBA in the suburban green areas, and from 49 to 60 dBA in the city parks (LAeq,15min). “Soundscape quality” was assessed by a five-point bipolar category scale. Among the respondents, 84-100% in the suburban green areas and 53-65% in the city parks assessed the soundscape as “Good” or “Very good”. Thus, all suburban green areas but none of the city parks reached the stipulated goal (at least 80%). The soundscape quality was confirmed by attribute profiling using a set of 12 adjectives. Based on the visitor’s responses, it is concluded that good soundscape quality can only be achieved if the traffic noise exposure in suburban green areas and city parks during day time is below 50 dBA.
Nilsson, M.E., & Berglund, B. (2006). Soundscapes in city parks and suburban green areas. In J. Hyurynen & R. Pääkönen (Eds.), EuroNoise 2006: Advanced Solutions for Noise Control. Tampere, Finland: European Acoustics Association, Paper SS25-349. [Available on CD]
According to guidelines proposed in Sweden, at least 80% of visitors in quiet areas should perceive the sound environment as good. This was the starting point for a questionnaire study conducted in four suburban green areas and in four city parks. The soundscape in the suburban areas was completely dominated by sounds from nature (e.g., bird song and sounds from water), whereas traffic noise was a main component of the city-park soundscapes. Measured equivalent sound levels (from all sources) ranged from 42 to 50 dBA in the suburban green areas, and from 49 to 60 dBA in the city parks. Between 84 and 100 % of the respondents in the suburban green areas and between 53 and 65 % of the respondents in the city parks assessed the soundscapes as “Good” or “Very good”. Thus, all the suburban green areas and none of the city parks reached the stipulated goal (at least 80%). Taken together, the results suggest that a good urban outdoor soundscape should (a) be dominated by positive sounds from nature, and (b) have an overall equivalent sound level below 50 dBA.
Nilsson, M.E., & Berglund, B. (2006). Noise annoyance and activity disturbance before and after the erection of a roadside noise barrier. Journal of the Acoustical Society of America, 119(4), 2178-2188.
Questionnaire studies were conducted in a residential area before and after the erection of a 2.25 m high noise barrier of conventional type along a heavily traveled road (19 600 vehicles/24 h). The interval between studies was two years. Houses closest to the barrier received a sound-level reduction from ~70.0 to 62.5 dB Lden at the most exposed facade. The sound-level reduction decreased with distance to the road, and was negligible for houses at more than 100 m distance. Up to this distance, the noise barrier reduced residents’ noise annoyance outdoors and indoors as well as improved speech communication outdoors. Indoors, speech communication and sleep disturbance were slightly but nonsignificantly improved.
Nilsson, M.E., & Berglund, B. (2006). Noise-mitigation efficiency of barriers. In C. Burroughs & G. Maling (Eds.), Inter-Noise 2006–Engineering a Quieter World. Washington, DC: The Institute of Noise Control Engineering of the USA, Inc., 2006, Paper 386.
To create acceptable sound environments in residential areas along heavily traveled main roads and railways, a common procedure is to build noise barriers. Noise barriers reduce residents’ noise annoyance. However, the extent of annoyancereduction may not be predictable from the corresponding reduction in A-weighted sound level. One reason for this is that noise barriers not only reduce the sound level, they also change the character of the noise, which may influence perceived annoyance. It is therefore a need for psychophysical research on the effect of noise mitigation on perceived annoyance. Two experiments were conducted, involving road-traffic and railway noise recorded with or without the influence of noise barriers. A linear function described fairly well the relationship between Aweighted sound level and perceived annoyance. However, roadtraffic noise recorded behind one barrier was found to be more annoying than predicted from the linear function. Zwicker Loudness level was found to be a better indicator of perceived annoyance than A-weighted sound level. This was especially true for sounds with relatively large proportion of low-frequency content. This is relevant for noise barriers, which always reduce high frequencies more than low frequencies and, thereby, increase the relative proportion of low-frequency content.
Nilsson, M.E., Berglund, B., & Axelsson, Ö. (2003). Soundscapes perceived by children and adults. In B. Berglund & E. Borg (Eds.) Fechner Day 2003. Stockholm: International Society for Psychophysics, pp. 199-204.
Different groups of children and adults (N=19-21) scaled loudness and emotional attributes (pleasantness, arousal, and control) of soundscapes recorded indoors and outdoors in the children’s home environment. Children and adults performed equally well in cross-modal matching of tape-measure-length to loudness. Their loudness relationships for reference sound levels (pink noise) and soundscapes also agreed well. Master scaled loudness of soundscapes was well predicted by average A-weighted sound level (LAeq,10s) for both children and adults. A weaker relationship was found between sound level and perceived pleasantness, supporting the view that A-weighted sound level is less meaningful as predictor of positive soundscape attributes. Moreover, children’s scale values of perceived pleasantness were significantly greater than the adult’s. This agrees with previous questionnaire and experimental studies showing that children have a higher tolerance than adults of soundscapes with traffic noise. Traffic noise exposures below 55 dBA over the 24 hours are needed in order to provide restorative soundscapes for children and adults in evening and night.
Nilsson, M.E., Botteldooren, D., & De Coensel, B. (2007). Acoustic indicators of soundscape quality and noise annoyance in outdoor urban areas. Revista de Acústica, 2007, 38 (3-4), Paper ENV01-002.
Acoustic indicators grounded in soundscape perception are needed for predicting the quality of soundscapes in urban outdoor areas. The present paper explores the predictive power of various acoustic indicators. A questionnaire study was conducted in 16 city parks and green open spaces in Stockholm. In total, 1116 respondents answered questions on, inter alia, perceived soundscape quality and road-traffic noise annoyance. One-third octave band levels were continuously logged during data collection. From these acoustic measurements, a number of indicators were calculated representing overall level, spectral content and time-variability of the soundscape. These indicators were calculated for each respondent separately, referring to the 10-min period during which the participant filled in the questionnaire. Indicators related to the overall sound level explained a substantial part of the variance in perceived soundscape quality and road-traffic noise annoyance. Indictors related to the spectral content only explained a small part of the variance not accounted for by overall sound level. Perception of nature sounds and technological sounds, as measured in the questionnaire, were strong predictors of soundscape quality and noise annoyance, also after adjusting for overall sound level. This suggests that prediction of soundscape quality would benefit from the development of acoustic indicators of sound source audibility within soundscapes.
Nilsson, M.E., Kaczmarek, T., & Berglund, B. (2004). Perceived soundscape evaluation of noise mitigation methods. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 514. [Available on CD]
Traffic noise mitigation changes the perceived soundscape. New methods were developed for characterizing such changes perceptually. The new methods involve sampling of large numbers of short excerpt soundscapes (5 s) from binaural soundscape recordings (at least 45 min). Summarizing perceptual data over a large number of soundscape excerpts identified the distinguishing feature of each soundscape, to be separated from the mere existence of common sounds, for instance, occasional sounds from people talking, footsteps and passing cars. Preliminary results from 12 listeners showed that they were able to discriminate between road-traffic noise-polluted soundscapes recorded before and after the erection of a noise barrier. Further research will determine psychophysical relationships for soundscape preference and annoyance, separately for different noise mitigation methods. These relationships will be used for evaluating the perceptual efficiency of different noise mitigation methods, in addition to the reduction accomplished in A-weighted sound level.
Nilsson, M.E. & Nougo, N. (2003). Noise sensitivity and soundscape perception. In B. Berglund and E. Borg (Eds.) Fechner Day 2003. Stockholm: International Society for Psychophysics, pp. 205-210.
In this psychoacoustical experiment, noise sensitive (N=13) and noise-insensitive (N=13) participants scaled 24 recorded soundscapes with respect to 12 perceptual attributes. On average, noise sensitive participants produced higher scale values on negative attributes than noise insensitive participants, but equal or lower values on neutral and positive attributes. Analysis of specific attributes showed a significant between-group difference for the attributes “loud”, “annoying” and “stressful”. For loudness, noise sensitive participants produced higher scale values than insensitive participants for high sound-level soundscapes (>40 dBA), but not for low sound-level soundscapes. For annoyance (and stressfulness), noise sensitive participants produced higher scale values than noise insensitive participants for all soundscapes, independent of sound level. Taken together, the results may be explained in terms of between-group differences in sound perception or in response style. Differences in sound perception would agree with a sensory sensitivity hypothesis. An explanation in terms of response style would require a statement that different perceptual attributes have different response functions.
Schiff, M., Hornikx, M. and Forssén, J. A numerical study of sound propagation over urban canyons. Proc. Euronoise, Paris, 2008.
Because quiet areas in dense urban environments are important, there is high interest in propagation to areas shielded from direct road traffic noise. Sound levels in shielded areas are strongly influenced by distant sources, so intermediate propagation factors such as metrology, screening, and intermediate canyons must therefore be addressed in a realistic propagation model. A numerical investigation of sound propagation across the open tops of intermediate urban canyons has been performed, using the Parabolic Equation and Equivalent Sources methods. Results have been collected for various canyon geometries, and the influence of multiple canyons, canyon/rooftop absorption, variable rooftop height, and correlated versus uncorrelated source models has been investigated. By characterizing the ”insertion loss” of canyons intermediate to the source and receiver, the influence of these intermediate canyons could be addressed simply, without the overhead of a detailed numerical calculation.
Skånberg, A. (2004). Community noise and sleep disturbances: Field and laboratory evaluations. Department of Environmental Medicine, The Sahlgrenska Academy at Göteborg University, Gothenburg, Sweden (licentiate thesis)
Aims: Community noise is often sleep disturbing in residential areas. Studies have shown greater noise-induced sleep disturbances in studies conducted in the laboratory than in field settings. One of the aims of this thesis was to investigate, using equal road traffic sound exposure, whether these differences exist and which methods (questionnaire or actigraphy) are most suitable for measuring noise-induced effects. Another aim was to compare subjects used to road traffic noise and those used to living in rather quiet surroundings: do they react similarly when noise-induced sleep disturbances are assessed in the laboratory compared to the home, using the same noise levels. The effect on sleep of ventilation noise, a common noise in residential areas, was also investigated.
Methods: Two studies were conducted in a sleep laboratory and in the subjects’ own homes. The sound exposure levels were set at realistic levels for residential areas, slightly above the level set in the guidelines adopted by the Swedish parliament and WHO. Study I involved eighteen subjects who lived in rather quiet surroundings. In the laboratory, they were exposed to road traffic noise, ventilation noise, or a combination of the two for six consecutive nights. In the home, they were exposed in their sleep to the same recorded road traffic noise as they were in the laboratory. Study II involved fourteen subjects who lived along a street with a rather high traffic load. They slept as usual in their homes for four nights, and were then exposed, for four nights, to their “home sound” in the laboratory. In both studies, the effects on sleep were assessed by actigraphy and questionnaires on sleep and mood.
Results: No differences in sleep quality were found when comparing sleep in the home to sleep in the laboratory when subjects were exposed to equal road traffic noise exposure, this being the case for both subjects used to road traffic noise or those used to living in quiet surroundings. Sleep quality decreased significantly after exposure to ventilation noise, road traffic noise, or a combination of the two, compared to sleep quality on the quiet reference night. The decreases were largest for the both intermittent noises, road traffic noise and the combined noise. The subject’s mood was not negatively affected by sleeping in the sleep laboratory.
Conclusions: The results indicate that laboratory experiments do not exaggerate sleep disturbances, and that when sleep is assessed using uniform methods, laboratory findings can be generalised to the home environment. Both subjects used to and not used to road traffic noise react alike when exposed to the same levels of road traffic noise in the laboratory and at home. Road traffic noise is more disturbing for sleep than ventilation noise at exposure levels slightly higher than those specified in the WHO guidelines. If the choice is between a busy road and a yard, it seems better to place the bedroom facing the yard even if it contains ventilation systems. Comparing actigraphy and questionnaire results, measurements of the effects on sleep obtained by questionnaire appear to be more reliable, since they consistently point in the same direction, i.e. reduced sleep quality after exposure to noise both in the laboratory and at home.
Skånberg, A. (2004). Road traffic noise induced sleep disturbances: a comparison between laboratory and field settings. Journal of Sound and Vibration, 277, 465-467.
The aim of this study was to investigate whether there were any differences in the effects of noise on sleep between studies performed in the laboratory and in field settings with equal road traffic noise exposure. Fourteen subjects, living along a street with a relatively high load of road traffic and with bedroom windows facing the street, slept four nights at home and four nights in a sleep laboratory, where they were exposed to played back “home road traffic noise”. Effects on sleep were evaluated by questionnaires and wrist-actigraphy. No significant differences in sleep quality were found between home and laboratory conditions on variables assessed either by questionnaires or wrist-actigraphy. It was concluded that laboratory experiments do not exaggerate the effects of road traffic noise on sleep, provided that sleep is studied with the same methods and that a homelike environment is created in the laboratory.
Skånberg, A., & Öhrström, E. (2002). Adverse health effects in relation to urban residential soundscapes. Journal of Sound and Vibration, 250, 151-155.
Skånberg A and Öhrström E (2006) Sleep disturbances from road traffic noise: a comparison between laboratory and field settings. J Sound Vib. Volume 290, Issues 1-2, 3-16.
The aim of this study was to investigate whether there were any differences in the effects of noise on sleep between studies performed in the laboratory and in field settings with equal road traffic noise exposure. Fourteen subjects, living along a street with a relatively high load of road traffic and with bedroom windows facing the street, slept four nights at home and four nights in a sleep laboratory, where they were exposed to played back ‘‘home road traffic noise’’. Effects on sleep were evaluated by questionnaires and wrist-actigraphy. No significant differences in sleep quality were found between home and laboratory conditions on variables assessed either by questionnaires or wrist-actigraphy. It was concluded that laboratory experiments do not exaggerate the effects of road traffic noise on sleep, provided that sleep is studied with the same methods and that a homelike environment is created in the laboratory.
Spang, K. (2006). Soundscape support to health – more than a research programme. In: Proc. Joint Baltic-Nordic Acoustical Meeting (BNAM 2006). Gothenburg, Sweden: The Swedish Acoustical Society
The research programme Soundscape support to health is a comprehensive 8-year programme aimed at development of the scientific basis, methods and models for creation of health supportive soundscapes in traffic noise exposed residential and recreational areas. It is mainly financed by the Swedish strategic environmental research fund – Mistra. Mistra supported research programmes shall contribute to solving important environmental problems and involve interdisciplinary research of high scientific standard. A specific responsibility of Mistra programmes is to bridge the gap between the researchers and their results on one hand and those affected by the environmental problems and responsible for activities for the abatement on the other hand. This introductory presentation includes a brief review of the research programme and projects for communication of its results.
A number of interesting results from the first six and a half years of the programme are presented in the session Soundscape support to health.
Spang, K. (2006). Soundscape support to health – more than a research programme. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 113. [Available on CD]
Our reaction to sound exposure is not only governed by the mean value and frequency weighting of the sound pressure. Variation in time and space has an influence as well as other factors – e.g. visual – which affect our sensory impressions. A perception based soundscape approach, involving knowledge from acoustics, environmental medicine and psychology, has the potential to take into account the total aspects of sound as a positive or negative factor. Knowledge from these fields has been utilized in the interdisciplinary Swedish research program Soundscape Support to Health. The research has been directed to development and application of methods and models for creation of positive soundscapes in traffic exposed residential and recreational city areas. Large-scale field studies and laboratory experiments have been used in the development and assessment of the methods and models. A communication program has been run in parallel, with the aims that the results from our research program, as well as from research by other scientists engaged in soundscape development, become known and applied in order to give our citizens access to soundscapes supportive to their health and well-being. The results from the research program will also be included in educational material at different levels, available on Internet.
Stansfeld, S.A., Clark, C., and on behalf of the RANCH Study team (B. Berglund, M.E. Nilsson, et al.). (2005). Implications of road traffic and aircraft noise exposure and children’s cognition and health (RANCH) study results for classroom acoustics. Journal of Acoustical Society of America. 2005, 117(4), 2363.
Studies in West London have found associations between aircraft noise exposure and children’s’ cognitive performance. This has culminated in the RANCH Study examining exposure-effect associations between aircraft and road traffic noise exposure and cognitive performance and health. The RANCH project, the largest cross-sectional study of noise and children’s health, examined 2844 children, 9-10 years old from 89 schools around three major airports: in the Netherlands, Spain and the United Kingdom. Children were selected by external aircraft and road traffic noise exposure at school predicted from noise contour maps, modelling and on-site measurements. A substudy indicated high internal levels of noise within classrooms. Schools were matched for socioeconomic position within countries. Cognitive and health outcomes were measured by standardized tests and questionnaires administered in the classroom. A parental questionnaire collected information on socioeconomic position, parental education and ethnicity. Linear exposure-effect associations were found between chronic aircraft noise exposure and impairment of reading comprehension and recognition memory, maintained after adjustment for mothers education, socioeconomic factors, longstanding illness and classroom insulation. Road traffic noise exposure was linearly associated with episodic memory. The implications of these results for children’s’ learning environments will be discussed.
Stansfeld, S.A., Berglund, B., Clark, C., Lopez-Barrio, I., Fischer, P., Öhrström, E., Haines, M.M., Head, J., Hygge, S., van Kamp, I., Berry, B.F., on behalf of the RANCH study team (M.E. Nilsson et al.). (2005), Aircraft and road traffic noise and children’s cognition and health: a cross-national study. Lancet , 365, 1942-1949.
Exposure to environmental stressors can impair children’s health and their cognitive development. The effects of air pollution, lead, and chemicals have been studied, but there has been less emphasis on the effects of noise. Our aim, therefore, was to assess the effect of exposure to aircraft and road traffic noise on cognitive performance and health in children. We did a cross-national, cross-sectional study in which we assessed 2844 of 3207 children aged 9-10 years who were attending 89 schools of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. We selected children by extent of exposure to external aircraft and road traffic noise at school as predicted from noise contour maps, modelling, and on-site measurements, and matched schools within countries for socioeconomic status. We measured cognitive and health outcomes with standardised tests and questionnaires administered in the classroom. We also used a questionnaire to obtain information from parents about socioeconomic status, their education, and ethnic origin. We identified linear exposure-effect associations between exposure to chronic aircraft noise and impairment of reading comprehension (p=0.0097) and recognition memory (p=0.0141), and a non-linear association with annoyance (p<0.0001) maintained after adjustment for mother’s education, socioeconomic status, longstanding illness, and extent of classroom insulation against noise. Exposure to road traffic noise was linearly associated with increases in episodic memory (conceptual recall: p=0.0066; information recall: p=0.0489), but also with annoyance (p=0.0047). Neither aircraft noise nor traffic noise affected sustained attention, self-reported health, or overall mental health. Our findings indicate that a chronic environmental stressor–aircraft noise –could impair cognitive development in children, specifically reading comprehension. Schools exposed to high levels of aircraft noise are not healthy educational environments.
Stansfeld, S.A., Berglund, B., Lopez Barrio, I., Fischer, P., Öhrström, E., Haines, M.M., Berry, B. on behalf of the RANCH Study Team. (2003). Aircraft and road traffic noise and children’s cognition and health: preliminary results on dose-response relationships from the RANCH study. In R.G. de Jong, T. Houtgast, E.A.M. Franssen & W.F. Hofman (Eds.), Noise as a Public Health Problem. Schiedam, The Netherlands: International Commission on Biological Effects of Noise (ICBEN), pp. 134-139.
Thorsson, P. (2002). A finite element model for sound propagation in complex cities. In Proceedings, Forum Acusticum, Sevilla, Spanish Acoustical Society, Spain, 2002. (Avaliable on CD, ISBN:84-87985-06-8)
Sound propagation in complex acoustic environments such as cities is in this paper studied by using the Boltzmann equation for stochastic molecular motion in a perfect gas. The equation is solved using a finite element approach, where the city is divided into its relevant parts such as roads, different building structures and recreational areas. Each part is characterized through its mean building size, mean absorption properties and the density and frequency spectrum of the sources present. The results from this method are not pointwise exact, but instead intended as a mean value of the background noise level.
Thorsson, P. (2002). Finite element application of linear transport to sound propagation in cities. In Proceedings, Tenth International Symposium on Long-Range Sound Propagation, Grenoble, France, September 12-13, 2002).
Sound propagation in complex acoustic environments such as cities is in this paper studied by using a linear transport equation. The relationship between the used equation and the wave equation is also given. The equation is solved using a finite element approach, where the city is divided into its relevant parts such as roads, different building structures and recreational areas. Each part is characterized through its mean building size, mean absorption properties and the density and frequency spectrum of the sources present. The results from this method are not pointwise exact, but instead intended as a mean value of the background noise level.
Thorsson, P. (2003). Prediction and Optimisation of Traffic Noise – A Study on Noise Barriers and Shielded Areas. Chalmers University of Technology, Applied Acoustics, F 03-06 [ISBN 91-7291-344-4]. (Ph.D. Thesis)
Thorsson, P. (2003). Application of linear transport to sound propagation in cities. Acta Acustica united with Acustica. (Submitted)
Thorsson, P., & Ögren, M. (2005). Macroscopic modeling of urban traffic noise–influence of adsorption and vehicle flow distribution. Applied Acoustics, 66(2), 195-209.
Thorsson, P., Ögren, M., & Kropp, W. (2004). Noise levels on the shielded side in cities using a flat city model. Applied Acoustics, 65(4), 313-323.
Ögren, M. (2004). Prediction of Traffic Noise Shielding by City Canyons. Göteborg: Department of Applied Acoustics, Chalmers, Report F04-01. Ph.D. Thesis. (ISBN 01-7291-438-6)
Reducing the sound level on the exposed building facades due to traffic noise in cities is difficult and expensive. Creating access for the inhabitants to a quiet side can be an alternative method for reducing the annoyance. Therefore it is of interest to predict the level on shielded positions such as courtyards. This is however difficult using traditional methods. Distant sources contribute to the level, and multiple reflections can be very important. The equivalent sources method is used here to make predictions for canyon-like geometries. This method is extended to include effects of diffusion, absorption and atmospheric turbulence in order to improve the predictions. Substantial decreases on quiet side sound levels have been shown when introducing absorption and diffusion, and small increases have been shown due to turbulence. Measurements indicate that the level is relatively constant for courtyards throughout a city area, and a very simple model called the flat city model is proposed to explain this effect. This model assumes that all sources and receivers are located on a flat rigid plane. The effect of shielding by buildings is introduced as a correction term determined from measurements, and this term is within a relatively small range (6-10 dB) for all the areas studied.
Ögren, M., & Forssén, J. (2001). Prediction of noise levels in shielded urban areas. In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Nederlands: Nederlands Akoestisch Genootschap (NAG), vol. 3, pp. 1223-1226.
In shielded urban areas the transfer paths for the traffic noise can be due to a variety of effects: multiple reflections, diffraction, refraction, and turbulence scattering. A typical situation with shielding is the quiet side of a tall building. For nearby sources some effects might be dominating, and other effects for distant sources. Predictions of noise levels are made using a ray-based model for a variety of shielded situations. The predictions are based both on sources close to the receiver and more distant ones. The results are compared with measurements, and the importance of the different transfer paths and sources are discussed.
Ögren, M., & Forssén, J. (2004). Modelling of a city canyon problem in a turbulent atmosphere using an equivalent sources approach. Applied Acoustics, 65(6), 629-642.
Ögren, M. & Kropp, W. (2002). An equivalent sources method solution to the 2D city canyon problem. In Proceedings, Tenth International Symposium on Long-Range Sound Propagation, Grenoble, France, September 12-13, 2002.
In shielded urban areas the transfer paths for traffic noise can be due to a variety of effects: multiple reflections, diffraction, refraction, and turbulence scattering. A typical situation with shielding is the quiet side of a tall building. Some transfer paths might be dominating for nearby sources, and other for distant sources. Predictions of noise levels are made using a ray-based model for a variety of shielded situations. The predictions are based both on sources close to the receiver and more distant ones. The results show that the calculations underestimate the level at shielded positions. It is necessary to improve the models in the areas of high order reflections, weather influence and secondary sources.
Ögren, M., & Kropp, W. (2002). The equivalent sources method applied to a 2D city canyon. In Proceedings, Forum Acusticum, Sevilla, Spanish Acoustical Society, Spain, 2002. (Avaliable on CD, ISBN:84-87985-06-8)
A common situation in an urban traffic environment is straight roads with high buildings on both sides, forming a city canyon. This problem can be simplified into a two dimensional situation where the road traffic is included as a line source. The problem can be divided into two domains, a room-like cavity and a free field above it. The two domains are then coupled by a set of sources. The model can be extended to a situation where one or more sources are located in one canyon and the receiver is located in an adjacent canyon.
Ögren, M., Forssén, J., & Kropp, W. (2003). Including turbulence and absorption effects in city canyon calculations. In A. Nilsson & H. Bodén (Eds.), International Congress of Sound and Vibration. Auburn, AL: International Institute of Acoustics and Vibration, vol. 3, pp. 1389-1396. (Available on CD)
Ögren, M., & Kropp, W. (2004). Road traffic noise propagation between two dimensional city canyons using and equivalent sources appraoch. Acta Acustica united with Acoustica, 90(2), 293-300.
Öhrström E. (2000). Sleep disturbances caused by road traffic noise–studies in laboratories and field. Noise & Health, 8, 71-78.
Field studies and laboratory experiments on noise-induced sleep disturbance show conflicting results and do not provide sufficient knowledge for valid exposure-effect relationships. It is also well known that habituation exists for awakenings whereas other effects such as heart rate reactions and minor EEG-reactions do not habituate. In this paper comparisons are made between findings from a series of laboratory and field studies on effects of road traffic noise on sleep performed by this athor. Possible reasons for the discrepancies found in various studies in laboratory and field are commented on and methods and research needs are discussed. Comparison of results obtained in research on perceived sleep quality parameters at this Department that used the same methods in laboratory and field studies showed fairly good agreement for difficulties in falling asleep and perceived sleep quality whereas awakening reactions were much less frequently reported in the field studies.
Öhrström, E. (2002). Adverse health effects before and after reduction in road traffic. In: A. Alippi (Ed.), The 17th International Congress on Acoustics. Rome, Italy: ICA Srl. [address: ICA Srl., Via Gelluno 16, Roma, Italy]. (Also available on CD)
The paper presents results from new field studies on the prevalence of adverse health effects before and one year after a substantial (90 %) reduction of road traffic. Previously performed studies in the same residential area in 1986 and 1987 before and after traffic regulations at night indicated that road traffic noise not only causes adverse effects on sleep quality but may also cause more long term effects on psycho-physiological health and well-being. These previous studies also showed that prohibition of heavy vehicles during night was not sufficient to reduce adverse effects on sleep and general well being. The new before study was performed in 1997 and the after study in 1999. The aim was to assess the adverse effects on people of long term exposure to road traffic in terms of, annoyance, activity disturbances, sleep quality and psycho-social well-being, as well as how people living in the area were affected by the changed traffic situation. The new study involved 142 individuals between 18 and 75 years of age, living between 25 and 450 metres from the heavily trafficed road. The main results were: a substantial reduction in noise annoyance, changed behaviors, increased sleep quality and reduced prevalence of psychological and physiological symptoms.
Öhrström, E. (2002). Before and after studies on sleep–Results and comparison of different methods. Noise & Health, 4:15, 65-67.
The effects of long-term exposure to road traffic noise on sleep quality were assessed using questionnaires and actimetry. Results obtained before and after reduction in road traffic were compared. Sleep quality was improved after the reduction of noise levels. There was some correlation between actimetry parameters and subjective parameters.
Öhrström E (2004). Longitudinal surveys on effects of changes in road traffic noise – effects on sleep assessed by general questionnaires and 3-day sleep logs. J Sound Vib vol 276, pp 713-727.
Adverse health effects including sleep disturbances by road traffic noise were studied among inhabitants in a residential area near Västra Bräckevägen in Göteborg city, Sweden, in 1986 and 1987, before and after the introduction of night traffic regulations. The results of those studies showed a higher prevalence of sleep disturbances and poorer sleep quality in the exposed areas as compared with the control area. This paper presents results on sleep based on new studies done with general questionnaires and daily sleep logs for a period of 3 nights in 1997 and 1999 in the same areas, before and after the opening of a new tunnel for road traffic. At this time, road traffic had been substantially reduced from about 25,000 to 2,400 vehicles per 24 h and from 1375 to 180 vehicles per night (22–06). It is concluded from these long-term investigations that exposure to high levels of road traffic noise induces adverse effects on sleep and that sleep quality is significantly improved after an extensive noise reduction. Sleep quality assessed by a single general questionnaire may give equally good precision as daily reports on sleep over several days. Furthermore, a higher response rate is achieved by a single questionnaire.
Öhrström, E. (2004). Longitudinal surveys on effects of road traffic noise – annoyance, sleep disturbance and psycho-social symptoms. Journal of the Acoustical Society of America, 115(2), 719-729.
The adverse effects of long-term exposure to a high volume of road traffic were studied in socio-acoustic surveys in 1997 and in 1999 after a substantial reduction in road traffic. The results obtained in 1997 showed a similar response pattern as in previously performed studies in the area in 1986 [Öhrström 1989]. In 1999, road traffic had been reduced from 25 000 to 2 400 vehicles per day and this resulted, not only in a large decrease in annoyance and activity disturbances, but also in a better general well-being. The results suggest that a reduction in both noise and other pollutants from road traffic contribute to these effects. To be able to use the outdoor environment and to have the possibility to keep windows open is essential for general well-being and daily behavior, which implies that access both to quiet indoor and outdoor sections of the residency is of importance for achievement of a healthy sound environment. More knowledge of long-term health consequences of exposure to noise and simultaneous pollutants from road traffic is needed. Studies should focus more on "softer" health outcomes and well-being than hitherto and preferably be performed in connection with traffic abatement measures.
Öhrström, E., and Gidlöf-Gunnarsson, A. (2006).The quiet side concept – benefits and limitations. In: In: Proc. Joint Baltic-Nordic Acoustical Meeting (BNAM) 2006. Gothenburg, Sweden: The Swedish Acoustical Society
Socio-acoustic surveys were carried out within the research programme “Soundscape Support to Health” to test if access to a quiet side of the dwelling enhance opportunities for relaxation, decrease noise annoyance and other adverse health effects related to noise. The results demonstrate a clear benefit of a quiet side (especially if this side also has high quality in other physical environmental aspects) corresponding to a reduction in sound levels of 5 dB at the most exposed façade. The “quiet side concept” is now being tested by a full-scale intervention project of a residential area exposed to high sound levels from road traffic. A quiet side will be created through new buildings that fill in gaps between houses facing the highway and through a considerable rebuilding of the dwellings. The paper discuss how soundscape design including “the quiet side concept” can be implemented in city and traffic planning in relation to findings obtained in the main study and results from the intervention project where a pre-study have been conducted.
Öhrström E., & Skånberg A. (2000). Adverse health effects in relation to noise mitigation–a longitudinal study in the city of Göteborg. In D. Cassereau (Ed.), Inter Noise 2000. Nice, France: INRETS, vol. 4, pp. 2112-2115.
Two socio-acoustic surveys on adverse health effects of road traffic noise were executed along Västra Bräckevägen in Gothenburg city, Sweden in 1986 and 1987 before and after traffic regulations during night. The results from these studies indicated that the traffic regulations were not effective in reducing the adverse effects of noise. This paper presents results from new studies performed 1997 and 1999 in the same area before and after the opening of a new tunnel for road traffic. The road traffic was reduced from about 25,000 to 2,400 vehicles per 24 hours and the percentage of highly annoyed respondents decreased from 58 to 7 percent. It is concluded from these long term investigations that exposure to high levels of road traffic noise not only induces adverse effects in terms of annoyance but also significantly affects sleep quality and psycho-physiological health and wellbeing.
Öhrström, E., & Skånberg, A. (2001). Does access to quiet areas reduce adverse health effects? In R. Boone (Ed.), Inter Noise 2001. Maastricht, The Netherlands: Nederlands Akoestisch Genootschap (NAG), vol. 3, pp. 1243-1248.
The aim of this study is to obtain knowledge of how various adverse health effects are related to individual noise exposures including access to a quiet side of the dwelling. Adverse health effects are evaluated by questionnaires in cross-sectional studies in the field. Five pairs of study sites will be selected with LAeq24h-levels from below 50 dB to levels higher than 65 dB. Each pair will consist of one residential area with buildings exposed to high level traffic noise on the street side, the opposite side being quiet, and one residential area with buildings exposed to a more moderate traffic noise on both sides of the dwelling. To clarify the effect-exposure relationship for various adverse health effects and the importance of having access to a quiet side of the dwelling, a much more detailed assessment of the noise immission in comparison with previously performed studies will be made. Preliminary results show only a tendency to lower general annoyance among residents who have access to a quiet side of the dwelling. The reason for this might be that the presumed quiet side was not perceived as quiet due to additional noise from a distant motorway. When analyses were performed in relation to position of living room windows and bedroom windows, significant results were demonstrated. Not being able to keep windows in the bedroom or in the living room opened due to noise occurred significantly more frequent among those without access to a quiet area in front of these rooms.
Öhrström, E. &Skånberg A. (2003). Sleep disturbances from noise – Laboratory study on road traffic and ventilation noise. In R.G. de Jong, T. Houtgast, E.A.M. Franssen & W.F. Hofman (Eds.), Noise as a Public Health Problem. Shiedam, The Netherlands: Foundation ICBEN 2003, pp. 185-186.
Introduction: Most research on noise-induced sleep disturbances has been conducted on transportation noise and very few studies have dealt with the effects of ventilation noise on sleep. It is vital to attenuate noise from outdoor ventilation systems mounted in courtyards, which often destroys an otherwise quiet environment in courtyards or at the rear of the building that is shielded from traffic noise. The aims of this study were to assess the effects on sleep of these to different types of noise exposures, typical for an open window situation. Methods: Eighteen healthy young subjects slept six nights in the laboratory and their sleep was evaluated with wrist actigraphs and questionnaires. The first two nights were for habituation. The third night was a quiet reference night and during the remaining 3 nights, subjects were exposed to recorded noise either from road traffic, ventilation noise or a combination of noise from ventilation and road traffic. The exposure levels were: traffic noise 39 LAeq ,23-07h with 64 passing vehicles 55LAmax , ventilation: 40 LAeq ,23-07h and the combined noise 43: LAeq ,23-07h. Results: Judged sleep quality was decreased by 22 % after nights with exposure to road traffic noise. The combined noise from ventilation and road traffic caused more awakenings; worse sleep quality (- 25 %) and more movements measured by questionnaire. None of these significant results was detected by actigraphy. The reason that combined exposure did not affect judged sleep quality more than exposure to traffic noise alone is probably explained by the fact that the combined noise had a more even and therefore less arousing character. It has previously been shown that an intermittent and fluctuating noise such as road traffic noise disturbs sleep more than an even noise. Noise from ventilation caused a decrease in judged sleep quality by 12 %, while sleep assessed by actigraph, indicated better sleep as compared with the quiet reference night. The reason for this discrepancy is not clear. Comments: Traffic noise is more disturbing for sleep than ventilation noise at exposure levels used in this study. It thus seems to be better to place a dwellings bedroom towards the courtyard even if there is ventilation equipment in the courtyard; it is a better solution than locating the bedroom towards a busy road. The effects on sleep obtained by questionnaires and by actigraphy were contradictory and the results obtained by questionnaires seem more reliable since they point in the same direction, e.g. reduced sleep quality after exposure to noise.
Öhrström, E., & Skånberg, A. (2003). Sleep disturbances from noise. Laboratory experiment on road traffic and ventilation noise. In R.G. de Jong, T. Houtgast, E.A.M. Franssen & W.F. Hofman (Eds.), Noise as a Public Health Problem. Schiedam, The Netherlands: Foundation ICBEN 2003, pp. 185-186.
Öhrström, E., & Skånberg, A. (2004). Sleep disturbances from road traffic and ventilation noise – laboratory and field experiments. Journal of Sound and Vibration, 271, 279-296.
The aims of this study were to assess the effects on sleep of different types of noise exposures (road traffic, ventilation and combination of noise from road traffic and ventilation) and compare effects on sleep both in laboratory and in field settings. Eighteen subjects slept 1 week in the laboratory and 1 week in their home and their sleep was evaluated with wrist actigraphs and questionnaires on sleep and mood. In the laboratory, judged sleep quality was decreased by 22% during nights with exposure to road traffic noise in the laboratory compared to the quiet reference night. The combined noise from ventilation and road traffic caused more awakenings; worse sleep quality (- 25%) and more movements reported by questionnaire. None of these significant results were detected by actigraphy. Noise from ventilation caused a decrease in judged sleep quality by 12%, while sleep assessed by actigraph indicated better sleep as compared with the quiet reference night. When comparing sleep with traffic noise exposure in the laboratory and in the home the results show no differences on sleep effects.
Öhrström E and Skånberg A (2004) Longitudinal surveys on effects of road traffic noise – substudy on sleep assessed by wrist actigraphs and sleep logs. Journal of Sound and Vibration, 272,1097-1109.
Öhrström E and Skånberg A (2004). Annoyance and activity disturbances caused by road traffic noise – field studies on the influence of access to quietness. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 159. [Available on CD]
Socio-acoustic surveys were carried out to assess health effects of various soundscapes in residential areas. The study was designed to test the hypothesis that having access to a quiet side of the dwelling enhances recovery and decreases annoyance and other adverse health effects related to noise. The dwellings in the different study sites chosen were exposed to sound levels from road traffic noise ranging from about LAeq,24h 45 dB to 68 dB at the most exposed side. The study involved 956 individuals aged 18 to 75 years. Half of them lived in dwellings with access to a quieter side and the other half had similar sound levels at the most exposed side but had no access to a quiet side. The results give clear evidence of health benefits of having access to a shielded, quieter section of the dwelling. Percentage annoyed respondents for sound levels of LAeq,24h 53-57 dB was lower (11 versus 22 %) if people had access to a shielded, quieter side of the dwelling. For sound levels of LAeq,24h 63-68 dB, the difference in annoyance was larger (38 versus 57 %) among those who had access to a quieter side. Disturbance of daytime restoration was the most pronounced daytime disturbance next to annoyance and possibilities to open the windows.
Öhrström E and Skånberg A (2004). Sleep disturbance from road traffic noise – field studies on the influence of access to quietness. In M. Brothanek & O. Jiricek (Eds.), Inter-Noise 2004. Prague: Czeck Acoustical Society, Paper 160. [Available on CD]
Socio-acoustic surveys were carried out within the research programme “Soundscape Support to Health” to assess sleep disturbances and other health effects of various soundscapes in residential areas. It was hypothesised that having access to a quiet side outside bedroom windows enhances recovery and decreases sleep disturbances related to noise. The dwellings in the different study sites chosen were exposed to different sound levels from road traffic noise ranging from about LAeq,22-06h 37 to 61 dB outside bedroom windows. The study involved 956 individuals. Half of them lived in dwellings with bedroom windows facing a quieter side and the other half had bedroom windows facing the most exposed side of the dwelling. A verbal category scale on frequency and degree of disturbance was used for evaluation of sleep disturbances due to road traffic noise (ability to sleep with bedroom windows slightly open, falling asleep, awakenings and sleep quality). Sleep quality was also evaluated by questions without reference to road traffic noise. The studies confirm previous findings of a relationship between sleep quality and individual factors such as state of health, psychological and physiological wellbeing and age, as well as perceived noise-induced sleep disturbances. The results show a strong relationship between sleep disturbances due to road traffic noise and demonstrate a large benefit from having access to a bedroom that faces a quiet side. The threshold for reported noise-induced sleep disturbances found in this study was a sound level outside bedroom windows 2 m from the façade LAeq,22-06 42-46 dB (windows slightly open).
Öhrström, E., Skånberg, Svensson, H., and Gidlöf Gunnarsson, A. (2006). Effects of road traffic noise and the benefit of access to quietness. Journal of Sound and Vibration, 295, 40-59.
Socio–acoustic surveys were carried out as part of the Soundscape Support to Health research programme to assess the health effects of various soundscapes in residential areas. The study was designed to test whether having access to a quiet side of one’s dwelling enhances opportunities for relaxation and reduces noise annoyance and other adverse health effects related to noise. The dwellings chosen were exposed to sound levels from road traffic ranging from about LAeq,24h = 45-68 dB at the most-exposed side. The study involved 956 individuals aged 18–75 years. The results demonstrate that access to quiet indoor and outdoor sections of one’s dwelling supports health; it produces a lower degree and extent of annoyance and disturbed daytime relaxation, improves sleep and contributes to physiological and psychological wellbeing. Having access to a quiet side of one’s dwelling reduces disturbances by an average of 30–50% for the various critical effects, and corresponds to a reduction in sound levels of (LAeq,24h) 5 dB at the most-exposed side. To protect most people (80%) from annoyance and other adverse effects, sound levels from road traffic should not exceed (LAeq,24h) 60 dB at the most-exposed side, even if there is access to a quiet side of one’s dwelling (LAeq,24h ≤45 dB).
Öhrström E, Skånberg A, Barregard L, Svensson H and Ängerheim P (2005). Effects of simultaneous exposure to noise from road- and railway traffic. In: Inter-Noise 2005. Rio de Janeiro: Brazilian Acoustical Society (SOBRAC), Paper 1570. [Available on CD]
Environmental noise, in particular road traffic noise, is a growing and well recognized environmental health problem. However, when noise from road traffic occurs simultaneously with noise from other sources, only limited knowledge exists of the effects on health. A socio-acoustic survey was conducted in residential areas in Lerum, a community east of Gothenburg, Sweden. Noise exposure was calculated for railway and road traffic separately and for the total noise exposure from both sources. The survey was conducted in areas with sound levels ranging from LAeq, 24h 45 dB - 72 dB for both road traffic and railway noise. A sample of 2905 persons aged 18 -75 years was selected. The response rate was 71 % (1953 persons). The objectives were to assess various adverse health effects and to clarify the possible impact of exposure to two noise sources. Preliminary results show that road traffic noise caused a somewhat lower extent of annoyance as compared to railway noise. In areas exposed to high sound levels both from road traffic and railway noise, there seemed to be an interaction effect for noise annoyance. This effect appeared at sound levels above LAeq,24h 55 dB. For both noise sources, the most common adverse effects were disturbances on sleep and relaxation during day time and for railway noise, disturbance of communication.
Öhrström E, Holmes M, Svensson H and Hadzibajramovic E. (2003). Adverse effects of road traffic noise – Comparison between young children and adults. In R.G. de Jong, T. Houtgast, E.A.M. Franssen & W.F. Hofman (Eds.), Noise as a Public Health Problem. Shiedam, The Netherlands: Foundation ICBEN 2003, pp 276-277.
Introduction: Many children are exposed to high levels of road traffic noise in their home environment and may also attend schools and other places/activities exposed to high levels of noise. Existing exposure-effect relationships do not take into account that people are exposed to varying sound levels during the 24 hours when staying in different parts of their dwellings, schools and adjacent outdoor areas. Adverse effects of noise exposure at school and other places may be moderated by noise exposure at home, especially due to opportunities for relaxation and sleep in quiet environments and provision of social support by adult carers. Very little comparative research exists between adverse effects on children and adults. The objective of this Swedish project within the RANCH-program was to (1) To provide knowledge on exposure-effect relationships between road traffic noise in the home and the effects on health and well being including sleep comparatively for young children and adults (2) To provide knowledge on exposure-effect relationships in children for road traffic noise in the home and the effects on cognitive function (working memory test “Letter Detective”) for young children. This paper presents a few preliminary results.
Öhrström E., Hadzibajramovic E., Holmes M., and Svensson H. (2006) Effects of road traffic noise on sleep – studies on children and adults. Journal of Environmental Psychology 26, 116-126.
Socio-acoustic studies were conducted in residential areas in Sweden exposed to different levels of road traffic noise. The objectives were to evaluate exposure-effect relationships between road traffic noise and sleep quality and to compare sleep assessed by sleep logs and wrist-actigraphy for children and parents. The main study involved interviews with 160 children (9 to 12 years old) and 160 parents. Half of the families also participated in an in-depth study in which their sleep was registered with sleep logs and wrist-actigraphy. For parents the results demonstrate a significant exposure-effect relationship between noise levels from road traffic and the following sleep parameters: sleep quality, awakenings, the habit of keeping windows closed at night and perceived interference with road traffic noise. For children a significant exposure-effect relationship was found between road traffic noise and sleep quality as well as problems with daytime sleepiness. Results from the in-depth study showed that children had better perceived sleep quality and fewer awakenings than parents, although sleep assessed by wrist-actigraphy indicated a better sleep for parents.
Öhrström, E., Andersson, E., Skånberg, A., Barregård, L.(2007). Relationships between annoyance and exposure to single and combined noise from railway and road traffic. In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 242 [Available on CD]
Environmental noise from traffic is a growing health problem. In many cases people are exposed to several types of noise sources at a time, e.g. road, railway, or aircraft noise, but the knowledge is limited of how combined noise sources affects annoyance. A socio-acoustic survey (n=1 953) was conducted in residential areas exposed to railway and road traffic noise ranging from LAeq,24h 45 - 72 dB (Lden 49 - 79 dB). The proportion annoyed by railway noise was higher in situations with simultaneous and equal exposure to road traffic noise than in situations with only railway noise, and corresponding results were found for annoyance due to road traffic noise. In areas exposed to both railway and road traffic, the proportion annoyed by the total traffic sound environment (total annoyance) was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same total sound exposure (LAeq,24h,tot). This interaction effect was significant from 59 dB and increased gradually with higher sound levels. The main conclusion is that the effects of the total sound exposure, and not only the effects of single sources, should be considered in risk assessments and in noise mitigation activities.
Öhrström E., Barregård B., Andersson E., Skånberg A., Svensson H., and Ängerheim P. (2007). Annoyance due to single and combined exposure from railway and road traffic noise. J Acoust. Soc. Am.122 (5): 2642-2652 Part 1, Nov 2007.
Environmental noise is a growing and well recognized health problem. However, in many cases people are exposed not to a single noise source — for example, road, railway, or aircraft noise — but to a combination of noise exposures and there is only limited knowledge of the effects on health of exposure to combined noise sources. A socio-acoustic survey among 1953 persons aged 18–75 years was conducted in residential areas exposed to railway and road traffic noise with sound levels ranging from LAeq, 24h 45 dB - 72 dB in a municipality east of Gothenburg, Sweden. The objectives were to assess various adverse health effects, including annoyance, and to elucidate the impact of exposure to single and combined noise sources. In areas exposed to both railway and road traffic, the proportion annoyed by the total traffic sound environment (total annoyance) was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same total sound exposure (LAeq,24h,tot). This interaction effect was significant from 59 dB and increased gradually with higher sound levels.Effects of the total sound exposure should be considered in risk assessments and in noise mitigation activities.
Öhrström, E., Gidlöf-Gunnarsson, A., Ögren, M. (2007). Listening experiments on effects of road traffic and railway noise occurring separately and in combination, In: Inter-Noise 2007. Istanbul: Turkish Acoustical Society, Paper 116. [Available on CD]
In urban areas, exposure to several noise sources is a common situation, and therefore, knowledge is needed for evaluating soundscapes with more than one dominant noise source. A recent, large field study indicated that noise annoyance significantly increased in situations with combined railway/road traffic noise exposure as compared to situations with one dominant source. The present experimental study examines responses (annoyance, listening disturbance) to road traffic and railway noise occurring separately or in combination. 24 subjects were exposed to four different noise situations with sound levels around guideline values for balconies/patios (road 53 dB, railway 53 dB, road+railway 53 dB, road+railway 56 dB) when listening to a played-back radio program during 10 min in each situation. The laboratory room was furnished as a living room and noise levels were chosen to simulate a situation with windows kept entirely open/outdoor situation. At 53 dB, road traffic noise alone caused higher annoyance, listening disturbance, and a more negatively perceived soundscape than railway noise alone. Annoyance due to each noise source when occurring separately increased with 38% for railway and 13% for road traffic when combined at 56 dB. This demonstrates the necessity to consider total sound exposure and not only single sources.
Reports in which program ideas and results have been implemented
CALM Network (2002). Research for a Quieter Europe. Brussels: European Commission, Research Directorate-General, Report EUR 20436, July 2002. [Co-authored by B. Berglund]
Noise pollution remains high on the list of citizen concerns and noise reduction has increasingly become a focus for EU legislation and a priority for industrial research. Despite enforcement of stringent legislation governing noise sources, and despite big effort and progress in noise control by the industry, little real improvement of citizen’s exposure levels have been achieved. The EU future noise policy is built on a long term target based on the 1996 Green Paper. The vision for the year 2020 is to “avoid harmful effects of noise exposure from all sources and preserve quiet areas”. The first goal of future research is to support the transposition of the Environmental Noise Directive (2002/49/EC), which contains preliminary texts since complementary information has still to be derived. The research strategy is to focus on further development of noise policy covering noise assessment and abatement, new technologies and system approaches for improved noise control at the source and legislative standards.
CEC. (2002). Directive 2002/49/EC of the European Parliament and the Council of 25 June 2002 relating to The Assessment and Management of Environmental Noise. Official Journal of the European Communities, L 189/12, 18.7.2002. [Expert advice from B. Berglund & T. Kihlman] [http://www.europa.eu.int/comm/environment/noise]
This directive shall apply to environmental noise to which humans are exposed in particular in built-up areas, in public parks or other quiet areas in an agglomeration, in quiet areas in open country, near schools, hospitals and other noise-sensitive buildings and areas. The aim of the directive shall be to define a common approach to avoid, prevent or reduce on a prioritized basis the harmful effects, including annoyance, due to exposure to environmental noise. To that end three main actions shall be implemented progressively: (a) determining the exposure to environmental noise, through noise mapping with common methods, (b) ensuring that information on environmental noise and its effects is made available to the public, (c) adopting action plans by Member States, based upon noise-mapping results, and (d) aiming at providing a basis for developing Community measures to reduce noise emitted by the major sources.
CEC.(2002). Position Paper on Dose Response Relationships between Transportation Noise and Annoyance. Luxenbourg: Office for Official Publications of the European Communities [COM (2000) 464 final, 2000-07-27]; February 20, 2002. [Co-authored by B. Berglund]
CEC. (2002). Inventory of Noise Mitigation Methods. Luxenbourg: Office for Official Publications of the European Communities [ ], July 218, 2002. [Co-authored by T. Kihlman]
The scope of this document was to explore present knowledge on the generation and propagation of as well as the exposure to sound energy. The inventory begins with the conditions connected with the interaction between tire/road and wheel/rail. Other abatement measures at source, which are treated in the text, are operational controls of the sources. Connection to the local level of decision, where appropriate, was maintained and emphasized. The inventor covers in principle the abatement of propagation of all types of environmental noise (traffic, industrial, leisure activities, and neighborhood). Ground transport has most of their abatement methods in common, and many of these are also applicable to industry, construction and leisure activities. Air traffic is in many practical respects an exceptional type of noise source as regards abatement. According to their importance, road and air traffic will inevitably receive most attention, with road vehicles as the globally most widely extended, and aircraft as the locally most dominating type of source.
Dora, C., & Phillips, M. 2000. (Eds.). Transport, Environment and Health. A Background Summary Document. Rome, Italy: World Health Organization, 2000 (in press). [Co-authored by B. Berglund]
CEC (2000). The Noise Policy of the European Union. Year 2 (1999-2000). Towards Improving the Urban Environment and Contributing to Global Sustainability. Luxembourg: Office for Official Publications of the European Communities. [Co-authored by B. Berglund]
[http://europa.eu.int/comm/pubs/home.htm]
CEC–WG HSEA (co-authored by B. Berglund). (2005). The Effectiveness of Noise Measures. Brussels: European Commission, WG HSEA Report, July 2005.
This Working Group Health and Socio-economic Aspects was set up by the European Commission in order to provide guidance on cost-effectiveness of noise reduction measures and the interaction between different such measures. Strong interactions were found between noise reduction measures taken at the EC level and at the local levels. Therefore, this research focused on finding additional knowledge on how to prioritize solutions. A model study was undertaken in order to predict the effects of noise abatement packages as regards their effectiveness. It was possible to demonstrate what constitutes an effective mix of noise measures for different sources (in scenarios). Ranking the solutions to noise problems was, in principle, guided by two criteria: effect reduction and cost-benefit ratio. Other considerations were equity (who pays the costs and who gets the benefits), the polluter pays principle and the time frame. Some measures have important consequences also in other areas, like air quality, safety, travel time, and energy. Based on the research results, the EC is advised: (a) To develop an ambitious strategy to achieve further noise reduction for road, rail and aircraft noise; (b) To carry out detailed analysis in the course of developing noise actions plans into the most cost-effective solution in their particular case; (c) To raise awareness of noise as a public health issue and to disseminate the knowledge on effective nose abatement.
Rust, A., & Affenzeller, J. (2004). CALM – Strategic planning of future noise research in Europe. In: Inter-Noise 2004. Prague, Czech Republic, August 22-25, 2004. (in press) [Expert advice from B. Berglund, partner of network]
The thematic EU network CALM acting from Oct. 2001 to Oct. 2004 aims at the definition of a strategy plan for future noise research in Europe. It shall promote the EU-wide reduction of environmental noise and thereby improve the quality of life for the citizens of Europe within the next twenty years. The CALM strategy paper issued in 2002 gives a first overview of the noise research priorities for the future. Meanwhile, the further activities of the network were focused on deepening and detailing the research needs and priorities in all relevant fields of environmental noise covering both noise emission and noise protection. The most important aspects of noise emission comprise traffic noise from road, rail and aircraft and noise from outdoor equipment. In order to put the outcomes of the network on a broad basis, special workshops with stakeholders from universities, research institutions and industry were held and provided a wide range of essential inputs. The paper describes the background as well as the overall status and results of the network with special emphasis on the latest findings about the research requirements in the fields of road traffic and railway noise.
WHO. (2000). Noise and Health. Local Authorities, Health and Environment. Copenhagen, Denmark: World Health Organization, Regional Office for Europe (edited by B. Berglund & C. Mascke).
Since the Middle Ages, it has been known that noise exposure at high sound levels can result in deafness after years of work–whether the noise comes from mining or church bell ringing. Many European countries now officially consider hearing loss at work as an industrial disease. It has been demonstrated that not only occupational noise but also environmental noise, such as from transport, may have a number of primary adverse effects including hearing impairment. For many people, noise is now a major environmental health problem, with traffic often the dominant noise source. Noise can often impair environments that otherwise would have been quiet and relaxing, such as backyards, gardens and parks. This document provides an overview of health effects of noise, among which WHO has identified interference with communication, noise-induced hearing impairment, annoyance responses, and effects on sleep, the cardiovascular and psychophysiological systems, performance, productivity and social behaviour. It also gives some guidance for developing policies aimed at noise management at local level.
WHO (2000). Guidelines for Community Noise. Geneva: World Health Organization, Guideline Document (ISBN: 9971-88-770-3), (edited by B. Berglund, T. Lindvall, D.H. Schwela, & K.-T. Goh).
Community noise (also called environmental, residential or domestic noise) is defined as noise emitted from all sources except noise at the industrial working place. Main sources of community noise include road, rail and air traffic; industries; construction and public work; and the neighbourhood. The main indoor noise sources are ventilation systems, office machines, home appliances and neighbours. The health significance of noise pollution is discussed according to specific effects: noise-induced hearing impairment, interference with speech communication, disturbance of rest and sleep, psychophysiological, mental-health and performance effects, effects on residential behaviour and annoyance, and interference with intended activities. Moreover, vulnerable groups and the combined effects of “mixed” noise sources are considered. Guideline values of maximum exposure are given for combinations of these specific health effects and the following specific environments: dwellings (daytime outdoors: 50-55 dB LAeq,16h; indoors: 35 dB LAeq,16h; but bedrooms indoors: 30 dB LAeq,8h and 45 dB LAmax), schools and preschools (playground outdoors: 55 dB LAeq; indoors during class: 35 dB LAeq; preschool bedrooms: 30 dB LAeq,8h and 45 dB LAmax), hospitals (treatment rooms: as low as possible; ward rooms indoors: 30 dB LAeq,8h nighttime, 30 dB dB LAeq,12h daytime), ceremonies, festivals and entertainment events (100 LAeq,4h and 110 dB LAmax), headphones/earphones (free-field value: 85 dB LAeq,1h and 110 dB LAmax), toys, fireworks and firearms (peak sound pressure 100 mm from the ear: 140 dB for adults and 120 dB for children), and parklands and conservation areas (existing large quiet outdoor areas should be preserved and the signal-to-noise ratio kept low). Noise management is discussed and recommendations given regarding strategies and priorities for indoor sound levels, noise policies and legislation, the impact of environmental noise, and the enforcement of regulatory standards. The guidelines also give recommendations on the implementation of the guidelines, further WHO work on noise, and research needs.
Abstracts only
Berglund, B. (2002). Towards a system for labeling soundscapes supportive to health. In E. Nair (Ed.), Abstract Guide of the IAAP Congress 2002. Singapore: International Association of Applied Psychology (IAAP), p. 46.
During the last two decades noise pollution has been increasing. Sustainable development would require a decrease. To accomplish this, nine environmental health principles have been proposed that should guide future noise policy and strategic actions. Current mitigation simply relies on reducing the sound level of noise thus neglecting the perceived qualities of soundscapes. Pleasing urban or suburban soundscapes are neither created by singular noise reduction, nor by providing quietness. A pleasing soundscape would consist of a composition of sounds in space and time resulting from people and their activities, from animals and nature itself, etc., taking into account effects of topography, atmosphere, insertions, etc. In order to design soundscapes we need to know what environmental components to manipulate and how. Therefore, new tools have been developed for characterizing the perceived soundscapes and their correlates, the acoustic soundscapes. Conventional acoustical measurements are unable to capture the soundscape variation in loudness and sound quality at different locations indoors and outdoors in noise exposed residential areas. It is not enough to assess merely individual sound events because the soundscapes are perceived in their entirety, i.e., beyond their sound-event constituents. Soundscapes may be characterized in their entirety as perceptual attribute profiles representing four features: “adverse”, reposing”, “affective” and “expressionless”. The most outstanding property of residential soundscapes is, however, their “echoey” quality. Since we have cultivated beautiful scenarios, developed impressive architecture and built functional cities, it is now time for “composing” and “labeling” healthy soundscapes.
Berglund, B., Hassmén, P., & Preis, A. (2000). Similarity and preferences in relation to annoyance of environmental sounds. In: Abstract Book of the 4th Japanese-Swedish Noise Symposium on Medical Effects Gothenburg, Sweden: Göteborg University, p. 56.
Previous research has suggested that similarity ratings are based on primarily cognitive processes, whereas preference judgments to a larger extent is based on affective processes. This notion was put to an empirical test using complex sounds as stimuli, and multidimensional scaling as the method of comparison. Results indicate that, contrary to the hypothesis expressed, a major proportion of the explained variance originates from the annoyance perceived by the individuals while listening to the sounds. Thus, both similarity ratings and preference judgments seem to be perceived as mainly affective by the subjects. A possible explanation for this unexpected results is the short period of time available to the subjects for making the estimations (6 seconds, i.e., the time between the sound). The subjects might have been ‘forced’ to use the factor or dimension most easily employed, thereby discarding other information that were present but not immediately available. If a longer time had been allowed between presentations, different results might have emerged.
Berglund, B., & Nilsson, M.E. (2001). An attempt to capture the perceived soundscape. In: Abstract Book from NOPHER 2001: An International Symposium on Noise Pollution & Health. London, UK: Institute of Laryngology & Otology, University College of London, p. 60.
A pleasing soundscape is neither created by reducing noise pollution, nor created by providing quietness. In urban areas the pleasing soundscape would consist of a composition of sounds from people and their activities, from animals and nature itself, etc. In order to design soundscapes we have to know what sounds are discerned and what sounds are adverse (e.g., annoyance) or positive (e.g., tranquillity). Therefore, new tools are needed for characterizing the perceived soundscapes. These tools should capture perceptual aspects that contribute to the citizens’ overall valuation of the soundscape. For this purpose we have developed tools for sound-source identification, quantification of loudness, and attribute-profiling of sound quality. The identification of sounds shows what sounds tend to emerge from the ambient sound. We have found that unwanted, discerned sounds contribute to the deterioration of the soundscape, although the corresponding contribution to the total or average sound level may be negligible. Conventional acoustical measurements are unable to capture the soundscape variation in loudness and sound quality at different locations indoors and outdoors in noise exposed residential areas. Moreover, qualitative “profiles” of the soundscape may be used for classifying perceived soundscapes based on valuations in fundamental perceptual dimensions. Finally, calibrated measurements of (perceived) loudness may replace sound level in the evaluation of various designs of the acoustical soundscapes, especially in areas with LAeq,24h < 55 dB. Since we have cultivated beautiful sceneries, developed impressive architecture and built functional cities, it is now time for “composing” wonderful soundscapes.
Berglund, B., & Nilsson, M.E. (2002). How is loudness of simultaneous and time-separated traffic noise integrated? In E. Nair (Ed.), Abstract Guide of the IAAP Congress 2002. Singapore: International Association of Applied Psychology (IAAP), p. 66.
Perceptual or psychophysical models of total loudness (or total annoyance) reflect views on summation of noise-source emissions (“bottom up”) or integration of information derived from noise immission(s), (“top down”). An analysis of data from laboratory and field studies of community noises shows that certain principles of information integration have to be accounted for in the model. These include what type of information is integrated (e.g., loudness of specific noises as heard alone or heard in combination with other noises), to what extent specific noises are partially masked and identified or merge, and what type of time pattern of specific noises exists. From this analysis, it became obvious that loudness- or energy-based psychoacoustical models have to be reinterpreted in a field framework. In field studies a specific noise in a noise combination may be reported to be louder (or more annoying) than the combined noise. Our theory, which accommodates such “compromise” outcomes, has been tested for highway and train noise with various time overlaps. As predicted, only combinations of unequally loud noises partially or completely separated in time produced compromise but not simultaneously presented noises. Consequently, a mathematical model of total loudness is provided which regards relative apparent on-time of specific noises of combined noise a crucial component of loudness integration. The systematicness of our empirical results supports the idea that compromise reflects loudness (or annoyance) integration principle rather than response bias. It most certainly is a perceptual-cognitive integration process.
Kihlman, T. (2002). Exploit the soundscape and reformulate traffic noise goals. In: Abstract Book of the First Pan-American/Iberian Meeting on Acoustics, December 2-6, 2002, Cancun, Mexico.
"Soundscape support to health" (www.soundscape.nu) is a 4 year research program including studies of traffic noise propagation in cities and different health effects of traffic noise. Special attention is given to the effect of access to a quiet side of dwellings. One goal of the program is to find more relevant goals than the present longterm general goal LAeq,24h<55 dB for all residents which on one hand is unrealistic and on the other hand does not imply a good environment - it is a compromise; at this level a substantial fraction of an exposed population is highly annoyed. However, the big spatial SPL variations within the city typically ranging from 40 - 70 dB can be systematically exploited. Traffic noise goals should therefore be reformulated to protect existing quietness and promote that all residents get access to a quiet environment within reach even though a typical level at facades facing the traffic will exceed 60 or 65 dB during a foreseeable future. The paper describes how the results from the program may be used to formulate goals that are more credible than the present and that lead to decreasing negative health effects of the traffic noise.
Kihlman, T. (2002) Possible and impossible goals for soundscapes in cities. In: The Sylvie Conference on New Approaches in Urban Noise Abatement, Vienna, Austria, October 24 -25, 2002.
The long-term goal in Sweden for the traffic noise outside dwellings is Laeq,24h<55 dB. This goal was originally set in the 60’ies. Similar goals have been set in some other countries in Europe. The goal appears much more remote today than when it was formulated. At the same time it does not represent a good acoustic environment. In the Swedish Action Plan against Noise (SOU 1993:65) the goal was characterized as an acceptable level whereas a good acoustic environment in urban dwellings should demand outdoor noise levels below 40-45 dB. It was argued that such low levels can be achieved on a shielded side of buildings in cities also when the traffic noise level on the directly exposed side is of the order of 60-65 dB. This has led to a much increased interest for the levels on the quiet side, which is also reflected in the EU Directive on Environmental Noise (yet final?). So it appears that the spatial variations of the noise levels in built up city structures is paid more attention to. Noise mapping should therefore be very detailed to serve as consumer information. In Sweden there is a standard for the acoustic classification of individual dwellings. In an ongoing research program in Sweden, Soundscapes for better health, both the effects of the soundscapes are studied and the details of sound propagation into shielded areas. Some results of the propagation studies show that current propagation models underestimate the levels in shielded positions.
Skånberg, A., & Öhrström, E. (2000). Adverse health effects in relation to individual noise exposure and perceived soundscape with and without access to quiet areas. In: Abstract Book of The 4th Japanese-Swedish Noise Symposium on Medical Effects. Göteborg, Sweden: Göteborg University.
The aim of the study is to obtain knowledge of how adverse health effects of noise, behaviours and self-estimated noise sensitivity are related to individual noise exposures in residential areas with and without access to a quiet side of the dwelling. Method: Adverse health effects are determined in cross-sectional studies in the field. Five pairs of study sites are selected for the studies. Each pair consists of one residential area with buildings exposed to high level traffic noise on the street side, the opposite side being quiet, and one residential area with buildings exposed to a similar or a somewhat more moderate traffic noise on the street side but with no access to a quiet side. Studies on adverse health effects are performed by questionnaires. The questionnaire contains questions on the living environment, the residence and the use of indoor and outdoor spaces for various activities including location of sleeping quarters. Questions are also asked about various sources of nuisance, annoyance, perceived sleep quality and a few brief questions on health, general physical and mental wellbeing as well as d self-estimated noise sensitivity. To clarify the effect-exposure relationship for various adverse health effects and the importance of having access to a quiet side of the residence, a much more detailed assessment and calculation of the noise immission are made, than in previously performed studies. Assessments of the individual noise exposure are made for the indoor and outdoors situation considering the location of bedroom, living room and balcony and areas for outdoors recreation. The noise exposure is assessed for LAeq day, evening and night, LAmax and number of noise events, L90, L10 as well as length of quiet periods between noise events. This paper will present preliminary results from the first pair of study sites at Hägerstensvägen in Stockholm.
Skånberg, A., & Öhrström, E. (2003). Sleep disturbances from road traffic noise a comparison between laboratory and field settings. In: Abstract Book of the 5th Japanese-Swedish Noise Symposium. Kirishima, Japan, May 19-23, 2003.
Field studies and laboratory experiments on noise-induced sleep disturbance show conflicting results and the accuracy of the results from laboratory experiments on sleep have sometimes been called into question. The aims of the study were to assess the effects on sleep of different types of noise exposures (road traffic, ventilation and combination of noise from road traffic and ventilation) and compare effects on sleep both in laboratory and in field settings. In this paper, results from the part of the study concerning road traffic noise exposure will be presented. Eighteen healthy young subjects who live in rather quiet residential areas participated. They were exposed to noise from road traffic in the laboratory and exposed to the same recorded traffic noise exposure in their own homes and their sleep was evaluated with wrist actigraphs and questionnaires on sleep and mood. The road traffic was recorded outdoors beside a motorway and mixed to consist of a total of 64 passing vehicles with a maximum level of car passages of 55±3 dB LA(f)max. The background level of the continuous traffic noise was 32 dB LAeq, 23-07h and the total level was 39 dB LAeq, 23-07h. The results indicate that laboratory experiments do not exaggerate effects of noise on sleep and that it is possible to compare sleep studies in the laboratory and field. However, new studies are needed where subjects who live in a relatively noisy home environment are exposed to the same noise in the laboratory as in their home environment.
Skånberg, A. & Öhrström, E. (2004) Comparative study on sleep disturbances from road traffic noise – Laboratory and field experiments. To appear in Inter-Noise 2004, Prague, Czech Republic, August 22-25, 2004.
Field studies and laboratory experiments on noise-induced sleep disturbance have shown differing results (results from field studies showed smaller effects of noise on sleep) and the accuracy of the results from laboratory experiments on sleep has been discussed. This study aims to clarify if it is possible to draw general conclusions from laboratory studies on sleep.
Two series of experiments were performed. In the first series eighteen subjects living in a rather quiet home environment participated. They slept six nights, both in the laboratory and in the home with equal road traffic noise exposure played back during the night. In the second series fourteen subjects living along a street with high traffic load participated. Their bedroom windows faced the street so they were habituated to sleeping with road traffic noise. These subjects slept five nights, as normal in their home and five nights in the laboratory with their “home traffic noise” played back during the night. The effects of noise on sleep were evaluated with wrist-actigraphy and questionnaires on sleep and mood.
No significant differences in sleep quality assessed with questionnaires were found between home and laboratory conditions. These results are obtained irrespective of if individuals are habituated to exposure from road traffic noise in their home environment or not. This indicates that laboratory experiments do not magnify effects of noise on sleep and that carefully controlled laboratory experiments give as reliable results as studies performed in the home environment.
Skånberg, A. & Öhrström, E. (2004) Annoyance and activity disturbances caused by road traffic noise – field studies on the influence of access to quietness To appear in Inter-Noise 2004, Prague, Czech Republic, August 22-25, 2004.
Socio-acoustic surveys were carried out to assess health effects of various soundscapes in residential areas. It was hypothesised that having access to a quiet side of the dwelling enhances recovery and decreases annoyance and other adverse health effects related to noise. The dwellings in the different study sites chosen were exposed to sound levels from road traffic noise ranging from about LAeq,24h 45 dB to 68 dB at the most exposed side. The study involved 956 individuals aged 18 to 75 years. Half of them lived in dwellings with access to a quieter side and the other half had similar sound levels at the most exposed side but had no access to a quiet side. The results give clear evidence of health benefits of having access to a shielded, quieter section of the dwelling. Percentage annoyed respondents for sound levels of LAeq,24h 53-57 dB was lower (11 versus 22 %) if people had access to a shielded, quieter side of the dwelling. For sound levels of LAeq,24h 63-68 dB, the difference in annoyance was larger (38 versus 57 %) among those who had access to a quieter side. If the goal is set to protect 90 % of the population from being annoyed by road traffic noise, the sound levels at the most exposed side of the dwelling should not be more than LAeq,24h 55 dB, even if there is access to a quiet side. The paper also compares annoyance in adults and children aged 9 to 12 years.
