Community response to aircraft noise in Ho Chi Minh City and Hanoi

To formulate Vietnamese and global noise policies, social surveys on community response to aircraft noise and combined noise from aircraft and road traffic were carried out in Ho Chi Minh City from August to September 2008 and in Hanoi from August to September 2009. In total, 1562 and 1397 responses were obtained in Ho Chi Minh City and Hanoi, respectively. The aircraft noise was measured for seven successive days, and the combined noise was measured for 24 h. Aircraft and combined noise exposures ranged from 53 to 71 dB and 73 to 83 dB L_den in Ho Chi Minh City and from 48 to 61 dB and 70 to 82 dB L_den in Hanoi, respectively. The dose–response curve for aircraft noise for Vietnam was established and fitted onto the curve for the European Union. For the same noise exposure, the aircraft noise annoyance in Hanoi was higher than that in Ho Chi Minh City because of the lower background noise level in Hanoi.     

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.     

Characteristics of road traffic noise in Hanoi and Ho Chi Minh City, Vietnam

Noise pollution due to road traffic is a major global concern because of its negative impact on the quality of life in communities everywhere. In Vietnam, traffic noise has become an increasingly noticeable and serious problem in large cities like Hanoi and Ho Chi Minh City. To gain more insight into the characteristics of this noise, intensive noise measurements were conducted in Hanoi and Ho Chi Minh City in September 2005 and September 2007, respectively. A comprehensive dataset of noise was obtained that included 24-h noise measurements as well as short-term noise recordings. The volume of traffic was also quantified by reproducing video camera recordings. Noise datasets from both cities were then compared with a dataset of Japanese traffic noise obtained in Kumamoto. The results showed that the traffic noise in Hanoi and Ho Chi Minh City was characterized by relatively high noise exposure levels due to the large number of motorbikes and frequent horn sounds. The sound of horns contributed a definite impact of 0-4 dB on noise exposure in Hanoi and Ho Chi Minh City, where noise levels decreased with the absence of horn sounds. Our results also showed differences in the characteristic traffic noise of Vietnam and Japan.     

A comparison of models to predict annoyance reactions to noise from mixed sources

Many residential communities are exposed to environmental noise from a mixture of sources. A simple energy summation model provides a convenient method for predicting annoyance reactions in mixed source situations but there is research evidence that the validity of its application is questionable. In this paper various alternative models are discussed. Their predictive powers are compared by using noise and social survey data collected at residential sites in the vicinity of Toronto International Airport. Sites were purposely selected to represent a range of aircraft and road traffic noise combinations. Of the five models examined, the simple energy summation model gives the poorest prediction of average annoyance. The strongest predictions are achieved by using independent effects and energy difference models. The implications of the results for predicting annoyance reactions to mixed sources are considered.     

Fuzzy models for accumulation of reported community noise annoyance from combined sources

Many scientists have investigated noise annoyance caused by combined sources. However, general annoyance reported in a social survey still has many unknown features. In this work the cognitive process involved in coming to a general noise rating based on a known, in context, rating of annoyance by particular sources is studied. A comparison of classical and fuzzy models is used for this. The new fuzzy linguistic models give a meaning to the successful strongest component or dominant source model that was used in previous work. They also explain to some extent particular features not included in that previous model. The variance not predicted by the fuzzy linguistic model is contrasted with personal data of the test subjects (age, gender, and education level) and the context of the question in the questionnaire. Only age seems to play a significant role.     

Comparison between train noise and road noise annoyance during sleep

Sleep disturbance by train and road noises was studied through in situ physiological recordings on two groups of people submitted to both types of exposure. At different sites acoustical parameters do not influence sleep in the same way. In a quiet place, emergence is an important factor of disturbance, but in a noisy place, noise duration and peak level are acting with interaction to disturb sleep.     

Comparison of telephone complaints and survey measures of noise annoyance

Sources of noise annoyance derived from spontaneous telephone complaints have been compared with responses to a household survey. Analysis of 31 months of telephone complaints for one Sydney municipality shows that noise from industrial and building sites are the two main sources of complaint. In the household survey, traffic and aircraft emerge as the two major sources of noise annoyance. There is no significant correlation between the two sets of data. The hypothesis that telephone complaints provide an indication of the rank order of sources of noise annoyance is rejected. It is concluded that telephone complaints should not be used to monitor noise pollution, at least in Sydney.     

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.     

Total annoyance from an industrial noise source with a main spectral component combined with a background noise

When living close to an industrial plant, people are exposed to a combination of industrial noise sources and a background noise composed of all the other noise sources in the environment. As a first step, noise annoyance indicators in laboratory conditions are proposed for a single exposure to an industrial noise source. The second step detailed in this paper involves determining total annoyance indicators in laboratory conditions for ambient noises composed of an industrial noise source and a background noise. Two types of steady and permanent industrial noise sources are studied: low frequency noises with a main spectral component at 100 Hz, and noises with a main spectral component in middle frequencies. Five background noises are assessed so as to take into account different sound environments which can usually be heard by people living around an industrial plant. One main conclusion of this study is that two different analyses are necessary to determine total annoyance indicators for this type of ambient noise, depending on the industrial noise source composing it. Therefore, two total annoyance indicators adapted to the ambient noises studied are proposed.     

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.     

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.     

Industrial noise levels and annoyance in Egypt

Annoyance and increase of accident risk of workers from industrial noise levels in Egypt were studied. 683 workers from 15 Egyptian sites of industry, ranging from food to metal industry were evaluated. The goals of this study are to carry out measurements to evaluate industrial noise levels, are these levels exceeded the permissible levels set by Egyptian noise standard and policy to protect public health of workers?, to examine worker’s attitudes towards industrial noise, to know the relationship between industrial noise levels and degree of annoyance. Results showed that equivalent continuous noise levels ranged from 70 to 100 dB (A). Annoyance of respondents showed that 47.1% were highly annoyed, 5.8% their hearing were harmed. There was a strong relationship between industrial noise levels and percentage of highly annoyed respondents. By increasing industrial noise level possibility of workers to make accident was also increased. Respondents suggest less maximum daily exposure duration than those set by Egyptian law.     

Choice of Japanese modifiers in noise annoyance scale during exposures to white noise

The linearity of a Japanese verbal scale of annoyance was estimated under real noise exposure. Young healthy adults, 32 male and 132 female were exposed to white noise of 30, 45, 60, 75 and 90 dBA in rooms where the exposure levels could be controlled according to contours. The series of noise exposure consisted of three components; white noise, pure-tone for conditioning and silence for evaluating noise. During the exposures the noisiness of each emission was evaluated with the verbal scale and a line-rating scale. The data showed a significant correlation of about 0.9 between the exposure level and the line length on the rating scale. The regression line of the noise level to the line length exhibited a reasonable locus of zero on the line length at the ambient noise level. The rank correlation between the selected modifier and the noise level was nearly 0.8 . When the five modifiers were converted to 1-5 points, respectively, the regression of the line length to the selected modifier revealed an adequate and consistent fitness (coefficient of determination was >0.8). The results suggest that the scale can be used as an equally divided linear scale in community noise research.     

Magnetoencephalographic responses correspond to individual annoyance of bandpass noise

The relation between human brain responses to an individual's annoyance of bandpass noise was investigated using magnetoencephalography (MEG) measurements and analysis by autocorrelation function (ACF) and cross-correlation function (CCF). Pure tone and bandpass noises with a centre frequency of 1000 Hz were used as source signals. The sound pressure level was constant at 74 dBA and the duration of the stimulus was 2.0 s. The scale values of annoyance for each subject were obtained by paired-comparison tests. In MEG measurements, the combination of a reference stimulus (pure tone) and test stimuli (bandpass noise) was alternately presented 30 times at a constant 2 s interstimulus interval. The results show that the effective duration of the ACF, τ_e, of MEG in the 8-13 Hz range, which represent repetitive features within the signal itself, became shorter during the presentation of an annoying stimulus. Also, the maximum value of the CCF, |φ(τ)|_max, became smaller. The shorter τ_e and smaller |φ(τ)|_max indicate that a wider area of the brain is unstable for longer with annoying auditory stimuli.     

A comparison between exposure-response relationships for wind turbine annoyance and annoyance due to other noise sources

Surveys have shown that noise from wind turbines is perceived as annoying by a proportion of residents living in their vicinity, apparently at much lower noise levels than those inducing annoyance due to other environmental sources. The aim of the present study was to derive the exposure-response relationship between wind turbine noise exposure in L(den) and the expected percentage annoyed residents and to compare it to previously established relationships for industrial noise and transportation noise. In addition, the influence of several individual and situational factors was assessed. On the basis of available data from two surveys in Sweden (N=341, N=754) and one survey in the Netherlands (N=725), a relationship was derived for annoyance indoors and for annoyance outdoors at the dwelling. In comparison to other sources of environmental noise, annoyance due to wind turbine noise was found at relatively low noise exposure levels. Furthermore, annoyance was lower among residents who received economical benefit from wind turbines and higher among residents for whom the wind turbine was visible from the dwelling. Age and noise sensitivity had similar effects on annoyance to those found in research on annoyance by other sources.     

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.     

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.     

Experimental study of annoyance due to low frequency environmental noise

We have carried out a study of a particular environmental noise phenomenon which appears to be a cause of real and severe disturbance to certain people. The study has been based on field measurements and on laboratory studies and questioning involving two people who have suffered from this problem for some years. The disturbance is heard by them as a ‘throbbing’ sound and is particularly prevalent indoors, rather than out-of-doors.The study has indicated that the phenomenon arises with a broad band spectrum which lies close to the hearing threshold and which is unbalanced to the extent that the major stimulus occurs in the frequency range 20–100 Hz. It is suggested that the unbalanced spectrum may arise as a result of low frequency noise generated by distant industrial sources.     

Relationship between low-frequency aircraft noise and annoyance due to rattle and vibration

A near-replication of a study of the annoyance of rattle and vibration attributable to aircraft noise [Fidell et al., J. Acoust. Soc. Am. 106, 1408-1415 (1999)] was conducted in the vicinity of Minneapolis-St. Paul International Airport (MSP). The findings of the current study were similar to those reported earlier with respect to the types of objects cited as sources of rattle in homes, frequencies of notice of rattle, and the prevalence of annoyance due to aircraft noise-induced rattle. A reliably lower prevalence rate of annoyance (but not of complaints) with rattle and vibration was noted among respondents living in homes that had been treated to achieve a 5-dB improvement in A-weighted noise reduction than among respondents living in untreated homes. This difference is not due to any substantive increase in low-frequency noise reduction of acoustically treated homes, but may be associated with installation of nonrattling windows. Common interpretations of the prevalence of a consequential degree of annoyance attributable to low-frequency aircraft noise may be developed from the combined results of the present and prior studies.     

Prediction of noise levels and annoyance from aircraft run-ups at Vancouver International Airport

Annoyance complaints resulting from engine run-ups have been increasing at Vancouver International Airport for several years. To assist the Airport in managing run-up noise levels, a prediction tool based on a Green's function parabolic equation (GFPE) model has been consolidated, evaluated, and applied. It was extended to include more realistic atmospheric and ground input parameters. Measurements were made of the noise-radiation characteristics of a CRJ200 jet aircraft. The GFPE model was validated by comparing predictions with results in the literature. A sensitivity analysis showed that predicted levels are relatively insensitive to small variations in geometry and ground impedance, but relatively sensitive to variations in wind speed, atmosphere type, and aircraft heading and power setting. Predicted noise levels were compared with levels measured at noise monitoring terminals. For the four cases for which all input information was available, agreement was within 10 dBA. For events for which some information had to be estimated, predictions were within 20 dBA. The predicted annoyance corresponding to the run-up events considered ranged from 1.8% to 9.5% of people awoken, suggesting that noise complaints can be expected.