Penalty for impulse noise, derived from annoyance ratings for impulse and road-traffic sounds

In the laboratory, four groups of 16 subjects rated the annoyance caused by three types of impulse sounds (regular and irregular gunfire noise and metal-construction noise) and by road-traffic sounds, all presented in background noise. The subjects were presented with the sounds for 5-min periods. The annoyance ratings were related to the A-weighted equivalent level (Leq) of the sounds. From these annoyance ratings a correction term or penalty was derived, which, added to the Leq of the impulse sounds, gives the level of equally annoying traffic noise. The correction was determined for conditions in which (1) only the annoyance caused by specific sources, or (2) the annoyance caused by the total sound (specific source plus background) had to be rated. In addition, the indoor Leq of the constantly present background noise was 35 or 55 dB(A) by and large, the results showed that for lower levels of the sounds an impulse-noise correction of at least 10 dB was required, whereas for higher levels the derived correction was about equal to the ISO/R 1996 penalty of 5 dB. This conclusion, based on the relation between Leq and annoyance ratings, is consistent with the correction based on Leq and the percentage of subjects who reported to be "very much annoyed." For equivalent levels of the impulse sounds at which 33% of the subjects claimed to be very much annoyed, the correction was 10 dB for the conditions in which the indoor Leq of the background noise was 35 dB(A), and 5 dB when this Leq was 55 dB(A).(ABSTRACT TRUNCATED AT 250 WORDS)     

On the annoyance caused by impulse sounds produced by small, medium-large, and large firearms

A laboratory study was designed in which the annoyance was investigated for 14 different impulse sound types produced by various firearms ranging in caliber from 7.62 to 155 mm. Sixteen subjects rated the annoyance for the simulated conditions of (1) being outdoors, and (2) being indoors with the windows closed. In the latter case, a representative outdoor-to-indoor reduction in sound level was applied. It was anticipated that the presumed additional annoyance caused by the "heaviness" of the impulse sounds might be predicted from the difference between the C-weighted sound exposure level (CSEL; LCE) and the A-weighted sound exposure level (ASEL; LAE). In the outdoor rating conditions, the annoyance was almost entirely determined by ASEL. The explained variance, r2, in the mean ratings by ASEL was 0.95. In the indoor rating conditions, however, the explained variance in the annoyance ratings by (outdoor) ASEL was significantly increased from r2 = 0.87 to r2= 0.97 by adding the product (LCE-LAE)(LAE-alpha) as a second variable. In combination with a 12-dB adjustment for small firearms, the present results showed that for the entire set of impulse sounds rated indoors with windows closed, the rating sound level, Lr, is given by Lr=LAE +12dB+beta(LCE-LAE)(LAE-alpha), with alpha=45dB and beta=0.015dB(-1). For the outdoor rating condition, the optimal parameter values were equal to alpha=57 dB and, again, beta=0.015 dB(-1). In validation studies, in which the effects of the present rating procedure will be compared to field data, it has to be determined to what extent the constants alpha and beta have to be adjusted.     

Annoyance caused by simultaneous impulse, road-traffic, and aircraft sounds: a quantitative model.

In this study, total annoyance caused by different simultaneous environmental sounds is investigated. In spite of a number of puzzling data in the literature, it is fairly well established that in combinations in which the annoyance of one source is considerably higher than that of another source, total annoyance is equal to the maximum annoyance of the separate sources. For combinations in which both sounds are about equally annoying, total annoyance seems to be higher than the maximum source-specific annoyance. The available data, however, are too rough to model total annoyance in these conditions. The present laboratory studies were therefore designed to explore further possible procedures to quantify total annoyance. Subjects rated the (total) annoyance caused by various combinations of impulse, road-traffic, and aircraft sounds. The results support a simple model which predicts the overall or total rating sound level L(t) for combinations of several types of sounds. Here, L(t) is numerically equal to the A-weighted equivalent sound level L(eq) of road-traffic sound with the same annoyance as caused by the combination of sounds. In the model, the sound exposure caused by the impulse and/or aircraft sounds is first expressed in the L(eq) of equally annoying road-traffic sound. With the help of source-specific dose-effect relationships, this is achieved by adding level-dependent penalties to the L(eq) of the respective sources. Weighted summation of the corrected L(eq)'s of the various sources then results in L(t). An optimal overall fit of the data from two separate experiments was obtained when the weighted summation of the corrected L(eq)'s was performed with the parameter k in k log(sigma 10(corrected L(eq) of source j)/k) set to 15. The standard deviation of the differences between the experimental results and the model predictions with k = 15 was equivalent to the small change in annoyance produced by a 1.5-dB shift in the L(eq) of road-traffic sound. Adoption of k = 15 implies that after correction, two equal L(eq)'s yield a total rating sound level which is 4.5 dB higher than each single-source corrected L(eq).     

Annoyance due to single and combined sound exposure from railway and road traffic

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 L(Aeq,24h) 45-72 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 (L(Aeq,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.     

The response to railway noise in residential areas in Great Britain

The effects of railway noise on residents have been measured with a combined social survey (1453 respondents) and noise measurement survey (over 2000 noise measurements) at 403 locations in 75 study areas in Great Britain. In the analysis of the data methods have been used which take into account many typical noise survey problems including noise measurement errors, unique locality effects and the weakness of the noise annoyance relationship. Railway noise bothers 2% of the nation's population. Approximately 170 000 people live where railway noise levels are above 65 dB(A) 24 hour L_eq. Annoyance increases steadily with noise level; thus there is no particular “acceptable” noise level. Railway noise is less annoying than aircraft or road traffic noise of equivalent noise level, at least above 50 to 65L_eq. Noise is rated as the most serious environmental nuisance caused by railways. Maintenance noise is rated as a bigger problem than passing train noise. Vibration is the most important non-noise problem. Reactions to vibrations are related to distance from route, train speed and number of trains. The railway survey's highly stratified, probability sample design with many study areas makes it possible to evaluate the effects of area characteristics on reactions. The 24 h L_eq dB(A) noise index is more closely related to annoyance than are other accepted noise indices examined. There is no support for ambient noise level or night-time corrections. Thirteen railway operation characteristics were examined. One, the type of traction, has a strong effect on reactions after controlling for L_eq (overhead electrified routes are the equivalent of about 10 dB less annoying at high noise levels). Three indicators of railway ancillary noises and non-noise environmental nuisances affect annoyance but most operational characteristics have no effect. The effects of over 35 demographic, attitudinal and neighbourhood characteristics on annoyance are examined. Though most objective characteristics of neighbourhoods and respondents are not correlated with annoyance, three do decrease annoyance (older dwellings, older respondents, and life-time residence). The attitudes which affect annoyance with railway noise are not general ones about railways as transportation sources, but rather ones which are specific to the neighbourhood setting or to railways as environmental intrusions in the neighbourhood. Such attitudes often have less effect on annoyance at low noise levels. In such cases it is the reactions of the more annoyed types of people which are most closely related to noise level.     

A -WEIGHTED EQUIVALENT SOUND LEVEL AS A PREDICTOR OF THE ANNOYANCE CAUSED BY ROAD TRAFFIC CONSISTING OF VARIOUS PROPORTIONS OF LIGHT AND HEAVY VEHICLES

A laboratory study was conducted to examine the relationship between noise annoyance and the proportion of heavy vehicles in a mixture of trucks and passenger cars. Twenty normal-hearing subjects were asked to judge the annoyance caused by the sounds from a continuous stream of vehicles, assuming they were exposed to it at home on a regular basis. The number of passby events as well as the A- weighted equivalent sound level were kept constant. Results showed that in such conditions, the annoyance is virtually independent of the proportion of heavy vehicles.     

Annoyance response to mixed transportation noise in Hong Kong

To better understand mixed transportation noise-annoyance response, a study was undertaken in Hong Kong to (1) unravel factors affecting annoyance response to mixed transportation noise; (2) contrast noise-annoyance relationships between road traffic and railway noise dominant situations; and (3) explain the differences, if any, between the two using structural equation modelling from the data collected in a social survey. Results of this study show that annoyance is largely determined by noise disturbance and perceived noisiness. Personal noise sensitivity, attitudes towards different means of transport and perceived quality of the living environment are secondary contributing factors. When road traffic noise dominates, annoyance is primarily determined by noise disturbance caused by the peaks of railway noise events; when railway noise dominates, peaks of train events can induce annoyance response directly without causing disturbance. Policy implications of such results on how to minimize noise-annoyance response are discussed in the paper.     

The differing annoyance levels of rail and road traffic noise

The results of a study on the relative annoyance by rail or road traffic noise in urban and rural areas are reported. Fourteen areas with rail and road traffic noise with differing levels of loudness (L_eq) were investigated. The annoyance was assessed by means of a questionnaire. The analysis of the relationship between annoyance and L_eq—performed separately for rail and road traffic noise—shows that the same amount of annoyance is reached for railway traffic noise at L_eq levels 4–5 dB(A) higher than for road traffic noise (railway/traffic noise “bonus”). The estimation for the difference values vary for the different variables of annoyance. Furthermore, the difference levels tend to be higher in urban than in rural areas.     

Longitudinal surveys on effects of changes in road traffic noise-annoyance, activity disturbances, and psycho-social well-being

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 [Ohrstr?m, J. Sound Vib. 122, 277-290 (1989)]. In 1999, road traffic had been reduced from 25000 to 2400 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.     

Relationship between exposure to multiple noise sources and noise annoyance

Relationships between exposure to noise [metric: day-night level (DNL) or day-evening-night level (DENL)] from a single source (aircraft, road traffic, or railways) and annoyance based on a large international dataset have been published earlier. Also for stationary sources relationships have been assessed. Here the annoyance equivalents model concerning noise annoyance from combined sources and the underlying assumptions are presented. The model first translates the noise from the individual sources into the equally annoying sound levels of a reference source, road traffic, and then sums these levels giving total level L. The annoyance from the combined sources is found by substituting exposure L in the road traffic exposure-annoyance relationship. The most important assumption, independence of the contributions of the sources, is discussed. It appears that independence will be violated substantially only due to the effect of the presence or absence of a quiet side of building which is not incorporated in the model. For use in practice the application of the model is broken down in five steps. The step by step procedure can be used for the assessment of the total noise level and the associated total annoyance on the basis of the DNL or DENL values of the individual sources.     

A- and C-weighted sound levels as predictors of the annoyance caused by shooting sounds,for various façade attenuation types

In a previous study on the annoyance caused by a great variety of shooting sounds [J. Acoust. Soc. Am. 109, 244-253 (2001)], it was shown that the annoyance, as rated indoors with the windows closed, could be adequately predicted from the outdoor A-weighted and C-weighted sound-exposure levels [ASEL (L(AE)) and CSEL (L(CE))] of the impulse sounds. The explained variance in the mean ratings by (outdoor) ASEL was significantly increased by adding the product (L(CE) - L(AE))(L(AE)) as a second variable. In the present study it was investigated to which extent the additional contribution of the second predictor is also relevant for fa?ade attenuation types with lower and higher degrees of sound isolation than applied previously. Twenty subjects rated the indoor annoyance caused by 11 different impulse types produced by firearms ranging in caliber from 7.62 to 155 mm, at various levels and for five fa?ade attenuation conditions. The effect of fa?ade attenuation on the ratings was large and consistent. In all conditions, an optimal prediction of the annoyance was obtained with outdoor ASEL as the first, and (L(CE) - L(AE))(L(AE)) as the second predictor. The benefit of the second predictor, expressed as the increase in the explained variance, ranged from 2.5 to 55 percent points, and strongly increased with the degree of fa?ade attenuation. It was concluded that for the determination of the rating sound level, the acoustic parameters ASEL and CSEL are very powerful. In addition, the results showed that for the whole set of impulses included, the annoyance could also be predicted very well by the weighted sum of indoor ASEL and the product (L(CE) - L(AE))(L(AE)).     

Reactions to railway noise in Denmark

People's reactions to railway noise were studied along seven Danish railway lines with traffic intensities from 30 to about 300 trains per 24 hours. The calculated sound levels varied between 43 and 71 dB(A) for L_Aeq,24h and between 78 and 102 sB(A) for L_Amax. 615 persons were interviewed. One third of these felt strongly or somewhat annoyed by the railway noise. The relations between the noise level and the extent of annoyance or various kinds of behaviour (telephone conversation, TV-listening, opening of windows, sleep, etc.) were found. The relations were found for both L_Aeq,24h and L_Amax, but the correlation for L_Amax is generally bad. Noise in the evenings was found to be more annoying than noise in other daytime periods. More than half of the interviewees answered that goods trains especially were a problem. People exposed to noise at their place of work seem to feel more annoyed by railway noise than other people.     

Railway noise and vibration annoyance in residential areas

This paper summarizes the results from the 1975 British railway noise study. Noise from railways does cause annoyance and interfere with activities. People in Great Britain appear to find high levels of railway noise to be somewhat less annoying than high levels from other sources. L_eq is as closely related to annoyance as any other index examined. Since annoyance increases steadily with noise level there is no particular “acceptable” railway noise level. Overhead electrified routes appear to be less annoying than diesel routes at the same noise levels. Through train noise, maintenance noise and vibration are the most widely noticed problems associated with railways in residential areas.     

Acoustical, sensory, and psychological research data and procedures for their use in predicting effects of environmental noises

A demonstration field-research study reveals that aircraft noise measured at two one-story houses is approximately 9 dB less attenuated from measured outdoor levels than is street traffic noise, and, found in other studies, approximately 14 dB less than railway noise. Comparable differences are found between these noises from the application of basic acoustical formulas for quantifying attenuations that occur on site of one- and two-story houses. Reasonably consistent with those findings are results from attitude surveys showing that daily exposure levels of aircraft must be approximately 8 dB less than levels of street traffic noise, and approximately 13 dB less than levels of railway noise to be perceived as an equal cause of annoyance and related adverse effects. However, USA government guidelines recommend that equal exposure levels of noise measured outdoors from vehicles of transportation should be considered as being equally annoying. Changes in present USA noise-measurement procedures and noise-control guidelines are proposed that provide more accurate predictions of annoyance, related adverse effects, and criteria for setting "tolerable" limits of noise exposure in residential areas. Key acoustical and psycho-acoustical principles and data pertaining to predicting correlations between dosages of environmental noises and its effects on people and land noise zoning in residential communities are examined.     

Annoyance reactions due to railway noise

Social survey studies to assess the presence of general annoyance were made in different areas exposed to railway noise. The results show that an increase in the number of passing trains increases annoyance up to a certain level, after which a levelling off takes place. Hence, there is no real annoyance in areas exposed to a maximum of 50 train passages/24 hours until the noise level reaches above 85 dB(A). If, on the other hand, train passages are 60 or more, annoyance increases according to the dB(A) level.     

几类典型环境声的主观评价及感知特性分析

近年来,通过“注入”调控声以降低交通噪声烦恼感的声频注入法受到广泛关注。以交通噪声调控研究为背景,通过成对比较评价了4类典型声音(实验一)和4类典型交通噪声(实验二)的烦恼感。结果表明,有调声(纯音和复音)烦恼度最高,自然声最低(海潮声最佳),蓝色噪声是仅次于海潮声令人感觉舒适的声音;被试对交通噪声和白噪声的评价存在明显的分类偏好。分析心理声学特征发现人对声音的感知依赖于多方面因素,但声刺激的某一因素(如粗糙度或音调特别高)特别突出则会引起极大的反感。构建不相似度二维感知空间,维度1反映了声音类型间的差异,维度2表征了被试对不同类型声音的烦恼度评价;并且通过相关分析发现它们与谱结构参量相关性较强。接下来的研究中,可以通过调整交通噪声的谱下降值和时域上升时间等参量使其谱结构更接近于自然声,从而降低噪声烦恼度。     

Road traffic noise - the relationship between noise exposure and noise annoyance in Norway

Exposure-effect relationships between the level of road traffic noise at the most exposed side of a dwelling's façade and the residents' reactions to road traffic noise have been estimated. The relationships are based on five Norwegian socio-acoustic studies featuring 18 study areas from two cities and a total of near 4000 respondents. The survey questionnaires distinguish between noise annoyance experienced right outside the apartment and when indoors. Exposure-effect relationships for all degrees of annoyance are estimated simultaneously from ordinal logit models. These predict road traffic noise annoyance when right outside the apartment and when indoors, respectively, as a function of the road traffic noise level outside the most exposed façade. Separate analyses indicate that Norwegians react stronger to road traffic noise than results from a recent compilation of socio-acoustic surveys would lead one to believe. People having inferior single glazing windows report higher indoor annoyance.     

Investigation of the dose-response relationship for road traffic noise in Assiut, Egypt

A field study has been carried out in urban Assiut city, Egypt. The goals of this study are: (1) to carry out measurements to evaluate road traffic noise levels, (2) to determine if these levels exceeds permissible levels, (3) to examine people’s attitudes towards road traffic noise, (4) to ascertain the relationship between road traffic noise levels and degree of annoyance. The measurements indicate that traffic noise noise levels are higher than those set by Egyptian noise standards and policy to protect public health and welfare in residential areas: equivalent continuous A - weighted sound pressure levels (L_A eq) = 80 dB and higher were recorded, while maximum permissible level is 65 dB. There is a strong relationship between road traffic noise levels and percentage of highly annoyed respondents. Higher road traffic noise levels mean that the percentage of respondents who feel highly annoyed is also increased.     

Comparing the relationships between noise level and annoyance in different surveys: A railway noise vs. aircraft and road traffic comparison

Annoyance expressed in a railway noise survey is compared with that in two road traffic and three aircraft surveys in order to determine whether responses to various environmental noises are similar or are source-specific. Railway noise is less annoying than other noises at any given high noise level. Railway noise annoyance increases less rapidly with increasing noise level. At high noise levels this gap in reactions averages about 10 dB but ranges from 4 dB to more than 20 dB. Comparisons between the findings in the different surveys can be made only after considering differences in noise index calculation procedures, human response measurement procedures and annoyance moderating conditions. The methodology for comparing surveys is examined. It is found that methodological uncertainties lead to imprecise comparisons and that different annoyance scales give different estimates of intersurvey differences.     

Community responses to road traffic noise in Hanoi and Ho Chi Minh City

Vietnam is a developing country in southeast Asia, and its environment has been seriously affected by industrialization and urbanization. In large cities like Hanoi (northern Vietnam) and Ho Chi Minh City (southern Vietnam), noise emission from road traffic has been found to be a serious concern among general public. In 2005 and 2007, two large-scale socio-acoustic surveys of community response to road traffic noise were conducted to investigate human reactions to road traffic noise in these cities; the sample sizes were 1503 people in Hanoi and 1471 in Ho Chi Minh City. The noise exposure levels (L_den) were 70–83 dB in Hanoi and 75–83 dB in Ho Chi Minh City. Noise annoyance was estimated using standardized annoyance scales. For both cities, dose–response relationships were established between L_den and the percentage of highly annoyed respondents. Compared to annoyance responses of European people, Vietnamese were less annoyed by road traffic noise by about 5 dB. Hanoi respondents seemed to be more annoyed by noise than Ho Chi Minh City respondents. Conversation and sleep disturbances were not as serious as expected in either city. Furthermore, window orientation in the home was found to affect activity disturbances.