Comparison of models to predict annoyance from combined noise in Ho Chi Minh City and Hanoi

Seven models were compared in terms of the ability to predict the annoyance due to the combination of aircraft and road traffic noises on the basis of data collected around airports in Ho Chi Minh City and Hanoi, Vietnam. The 24-h average sound levels L_Aeq,24h and unweighted means of annoyance scores for aircraft, road traffic, and combined noise were used to solve the regression equations for the seven models. The results indicate that road traffic noise exposure and annoyance were more than those of aircraft noise at almost all sites in both Ho Chi Minh City and Hanoi. Among the considered models, the dominant source model yielded the highest coefficients of determination, with R² values of 0.82 and 0.90 for surveys in Ho Chi Minh City and Hanoi, respectively. These results suggest that the dominant source model is the most useful model in the vicinity of those airports in Vietnam where road traffic noise is more dominant than aircraft noise. This is convenient for situations in which dose-response curves are established separately for different noise sources.     

Testing a theory of aircraft noise annoyance: a structural equation analysis

Previous research has stressed the relevance of nonacoustical factors in the perception of aircraft noise. However, it is largely empirically driven and lacks a sound theoretical basis. In this paper, a theoretical model which explains noise annoyance based on the psychological stress theory is empirically tested. The model is estimated by applying structural equation modeling based on data from residents living in the vicinity of Amsterdam Airport Schiphol in The Netherlands. The model provides a good model fit and indicates that concern about the negative health effects of noise and pollution, perceived disturbance, and perceived control and coping capacity are the most important variables that explain noise annoyance. Furthermore, the model provides evidence for the existence of two reciprocal relationships between (1) perceived disturbance and noise annoyance and (2) perceived control and coping capacity and noise annoyance. Lastly, the model yielded two unexpected results. Firstly, the variables noise sensitivity and fear related to the noise source were unable to explain additional variance in the endogenous variables of the model and were therefore excluded from the model. And secondly, the size of the total effect of noise exposure on noise annoyance was relatively small. The paper concludes with some recommended directions for further research.     

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.     

Interactive simulation of aircraft noise in aural and visual virtual environments

This paper describes a novel aircraft noise simulation technique developed at RWTH Aachen University, which makes use of aircraft noise auralization and 3D visualization to make aircraft noise both heard and seen in immersive Virtual Reality (VR) environments. This technique is intended to be used to increase the residents’ acceptance of aircraft noise by presenting noise changes in a more directly relatable form, and also aid in understanding what contributes to the residents’ subjective annoyance via psychoacoustic surveys. This paper describes the technique as well as some of its initial applications. The reasoning behind the development of such a technique is that the issue of aircraft noise experienced by residents in airport vicinities is one of subjective annoyance. Any efforts at noise abatement have been conventionally presented to residents in terms of noise level reductions in conventional metrics such as A-weighted level or equivalent sound level L_eq. This conventional approach however proves insufficient in increasing aircraft noise acceptance due to two main reasons – firstly, the residents have only a rudimentary understanding of changes in decibel and secondly, the conventional metrics do not fully capture what the residents actually find annoying i.e. characteristics of aircraft noise they find least acceptable. In order to allow least resistance to air-traffic expansion, the acceptance of aircraft noise has to be increased, for which such a new approach to noise assessment is required.     

The relationship between civil aircraft noise and community annoyance in Korea

Studies of community annoyance caused by civil aircraft noise exposure were carried out in 18 areas around Gimpo and Gimhae international airports in order to accumulate social survey data and assess the relationship between aircraft noise levels and annoyance responses in Korea. WECPNL, adopted as the aircraft noise index in Korea, and the percentage of respondents who felt highly annoyed (%HA) have been used to assess the dose-response of aircraft noise. Aircraft noise levels were measured automatically by airport noise monitoring system, B&K type 3597. Social surveys were carried out to people living within 100 m of noise measurement points. The Questionnaire used in the survey contained demographic factors, noise annoyance, interference with daily activities and health-related symptoms. The question relating to the aircraft noise annoyance was answered on an 11-point numerical scale. The randomly selected respondents who were aged between 18 and 70 years completed the questionnaire by themselves. In total, 705 respondents participated in the questionnaire. The results show that WECPNL, noise metric considering characteristics of event and intrusive noise, is more reasonable than L_dn, noise metric considering total sound, to assess the effects of aircraft noise on health. It is also shown that the annoyance responses caused by aircraft noise in Korea seems higher than those reported in other countries.     

Effect of background noise levels on community annoyance from aircraft noise

A study of community annoyance caused by exposures to civil aircraft noise was carried out in 20 sites around Gimpo and Gimhae international airports to investigate the effect of background noise in terms of dose-effect relationships between aircraft noise levels and annoyance responses under real conditions. Aircraft noise levels were mainly measured using airport noise monitoring systems, B&K type 3597. Social surveys were administered to people living within 100 m of noise measurement sites. The question relating to the annoyance of aircraft noise was answered on an 11-point numerical scale. The randomly selected respondents, who were aged between 18 and 70 years, completed the questionnaire independently. In total, 753 respondents participated in social surveys. The result shows that annoyance responses in low background noise regions are much higher than those in high background noise regions, even though aircraft noise levels are the same. It can be concluded that the background noise level is one of the important factors on the estimation of community annoyance from aircraft noise exposure.     

Evaluating noise in social context: the effect of procedural unfairness on noise annoyance judgments

General dosage-response curves typically over- or underestimate the actual prevalence of noise annoyance for specific groups of individuals. The present study applies a social psychological approach to noise annoyance that helps to understand and predict collective deflections from the curve. The approach holds that being exposed to man-made sound is more than mere exposure; it is a social experience, too: You expose Me. In effect, social aspects of the situation, like the evaluation of the sound management procedure, influence the evaluation of sound. The laboratory experiment (N=90) investigates the effect of procedural unfairness on noise annoyance. The sound management procedure is varied systematically: Participants are promised they will listen to the sound of their choice (i.e., bird song, radio sound, or aircraft sound) but receive aircraft sound despite their expressed preference (unfair procedure), or they are simply told they will listen to aircraft sound (neutral procedure). All are exposed to aircraft sound (50 or 70 dBA Leq). A collective rise in noise annoyance is predicted in the unfair relative to the neutral procedure conditions. Results show that noise annoyance ratings are significantly higher in the unfair relative to the neutral conditions. Consequences for theory and practice are discussed.     

The role of noise sensitivity in the noise-response relation: a comparison of three international airport studies

In order to examine the role of noise sensitivity in response to environmental noise, this paper presents detailed comparisons of socio-acoustic studies conducted around international airports in Amsterdam, Sydney, and London. Earlier findings that noise sensitivity moderates the effect of noise on annoyance were examined to see if they could be replicated in each of the datasets, independent of the technique of measuring noise sensitivity. The relation between exposure to aircraft noise and noise annoyance was studied separately for groups of individuals with low, medium, and high noise sensitivity, with statistical adjustment for relevant confounders. Results support the previous findings that noise sensitivity is an independent predictor of annoyance and adds to the prediction of noise annoyance afforded by noise exposure level by up to 26% of explained variance. There is no evidence of a moderating effect, whereby the covariation between noise exposure level and annoyance is weak for people who score at the extreme high or low end of the sensitivity scale, and strong for people who score in the middle of the sensitivity scale. Generally, noise sensitivity appears to increase annoyance independently of the level of noise exposure after adjustment for relevant confounders. These findings were consistent across the three datasets.     

Aircraft noise annoyance modeling: Consideration of noise sensitivity and of different annoying acoustical characteristics

Noise annoyance due to aircraft flyover noise was assessed under laboratory conditions. The main objectives of the study were: (i) to identify influential acoustical features of noise annoyance, (ii) to propose noise indices to characterize these acoustical features and (iii) to enhance annoyance models including influential acoustical and non-acoustical variables. Therefore, a verbalization task was performed by the participants of the experiment to collect their whole impression concerning the aircraft flyover noises for which they rated annoyance. This verbalization task highlights that noise annoyance was influenced by three main acoustical features: (i) the spectral content, (ii) the temporal variation and (iii) the perceived sound intensity. Four combinations of noise indices were used to propose multilevel annoyance models, in combination with the individual noise sensitivity. Noise sensitivity was found to highly contribute to annoyance models and should therefore be considered in future studies dealing with noise annoyance due to aircraft noise. Different combinations of noise indices coupled with noise sensitivity were found to be promising for future studies that aim to enhance current annoyance models.     

Some developments in community response research since the second international workshop on railway and tracked transit system noise in 1978

As far as human responses to railway noise are concerned, knowledge has increased considerably since the Second International Workshop on Railway and Tracked Transit System Noise was held in Lyon, France, in October 1978. Only some developments are mentioned in this article. Concerning land use planning some evidence became available that in maintaining or recovering a certain amount of well-being the concept of noise zoning deserves most attention, and that applying heavier sound insulation measures is not sufficient in solving the problem of noise annoyance. About the influence of background noise on annoyance, data from railway noise surveys are not conclusive. Whether or not habituation to noise occurs seems to be dependent on the way it has been made operational. Neither the often used self-reported habituation nor length of residence appears to have a clear relation with annoyance. Noise from shunting yards appears to be very annoying, compared with noise from through trains, road traffic and aircraft. The characteristics of the noise causing this relatively high degree of annoyance are still subject to study. “Normal” through trains cause less annoyance than road traffic and aircraft, the noise levels being equal. Some specific disturbances, however, like for instance being disturbed while watching television or having a conversation, occur at lower noise levels with railway noise than with road traffic noise.     

Role of community tolerance level (CTL) in predicting the prevalence of the annoyance of road and rail noise

Fidell et al. [(2011), J. Acoust. Soc. Am. 130(2), 791-806] have shown (1) that the rate of growth of annoyance with noise exposure reported in attitudinal surveys of the annoyance of aircraft noise closely resembles the exponential rate of change of loudness with sound level, and (2) that the proportion of a community highly annoyed and the variability in annoyance prevalence rates in communities are well accounted for by a simple model with a single free parameter: a community tolerance level (abbreviated CTL, and represented symbolically in mathematical expressions as L(ct)), expressed in units of DNL. The current study applies the same modeling approach to predicting the prevalence of annoyance of road traffic and rail noise. The prevalence of noise-induced annoyance of all forms of transportation noise is well accounted for by a simple, loudness-like exponential function with community-specific offsets. The model fits all of the road traffic findings well, but the prevalence of annoyance due to rail noise is more accurately predicted separately for interviewing sites with and without high levels of vibration and/or rattle.     

An assessment of certain causal models used in surveys on aircraft noise annoyance

The causal relationships which have so far been proposed between aircraft noise exposure, annoyance and certain “psycho-social” variables (fear of aircraft crashing, general attitude towards aviation, etc.), are re-analysed, and it is demonstrated that by using correlational analysis one can arrive at contradictory results. From the sociological surveys undertaken to date, one can derive only an ordered sequence of verbal reactions to aircraft noise, and not a causal sequence between these verbal reactions: the only clear cause of annoyance is the noise itself.It is suggested that future surveys on noise annoyance should include personality tests and health questionnaires, if one wishes to establish reliable causal sequences.     

Annoyance with aircraft noise in local recreational areas and the recreationists' noise situation at home

Few socioacoustic studies have examined the effect of noise on outdoor recreationists. Most studies concentrate on one setting of the everyday life of a noise-exposed population, which mainly has been the residential setting. This article relates annoyance with aircraft noise in outdoor recreational areas to the recreationists' noise situation at home. In conjunction with the relocation of the main airport of Norway in 1998, field studies were conducted before and after the change in one area near the old airport (1930 survey respondents), and one area near the new airport (1001 survey respondents). Multivariate linear regression analyses of the relationship between annoyance and aircraft noise exposure (LAeq for the aircraft events) in the recreational areas were conducted, controlled for noise annoyance at home, or aircraft noise exposure at home, the situation (before/ after the change), context- and demographic variables. People more highly annoyed at home tended to be more annoyed than others while in the recreational areas. A significant effect of aircraft noise exposure at home on annoyance in the recreational setting was not found. More research is warranted regarding the relationship between noise exposure at home and outdoor recreational demands.     

Trends in aircraft noise annoyance: the role of study and sample characteristics

Recently, it has been suggested that the annoyance of residents at a given aircraft noise exposure level increases over the years. The objective of the present study was to verify the hypothesized trend and to identify its possible causes. To this end, the large database used to establish earlier exposure-response relationships on aircraft noise was updated with original data from several recent surveys, yielding a database with data from 34 separate airports. Multilevel grouped regression was used to determine the annoyance response per airport, after which meta-regression was used to investigate whether study characteristics could explain the heterogeneity in annoyance response between airports. A significant increase over the years was observed in annoyance at a given level of aircraft noise exposure. Furthermore, the type of annoyance scale, the type of contact, and the response percentage were found to be sources of heterogeneity. Of these, only the scale factor could statistically account for the trend, although other findings rule it out as a satisfactory explanation. No evidence was found for increased self-reported noise sensitivity. The results are of importance to the applicability of current exposure-annoyance relationships for aircraft noise and provide a basis for decisions on whether these need to be updated.     

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.     

Noise within the social context: annoyance reduction through fair procedures

The social context of noise exposure is a codeterminant of noise annoyance. The present study shows that fairness of the exposure procedure (sound management) can be used as an instrument to reduce noise annoyance. In a laboratory experiment (N = 117) participants are exposed to aircraft sound of different sound pressure level (SPL: 50 vs 70 dB A)--which is experienced as noise--while they work on a reading task. The exposure procedure (fair versus neutral) is modeled in line with findings from social justice theory. In the fair condition, participants can voice their preference for a certain sound sample, although they cannot deduce whether their preference is granted. In the neutral condition, participants are not asked to voice their preference. Results show the predicted interaction effect of sound pressure level and procedure on annoyance: Annoyance ratings are significantly lower in the fair condition than in the neutral condition, but this effect is found only in the 70 dB condition. When the SPL is considerably disturbing, fair procedures reduce noise annoyance. Consequences of the reported findings for both theory and practice are discussed.     

Synthesis of social surveys on noise annoyance.

Since noise was first recognized as a serious environmental pollutant, a number of social surveys have been conducted in order to assess the magnitude of the problem and to develop suitable noise ratings, such that, from a measurement of certain physical characteristics of community noise, one could reliably predict the community's subjective response to the noise. Recently, the author has reviewed the data from social surveys concerning the noise of aircraft, street traffic, expressway traffic, and railroads. Going back to the original published data, the various survey noise ratings were translated to day-night average sound level, and an independent judgment was make, where choice was possible, as to which respondents should be counted as "highly annoyed." The results of 11 of these surveys show a remarkable consistency. It is proposed that the average of these curves is the best currently available relationship for predicting community annoyance due to transportation noise of all kinds.     

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).     

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)