Showing papers on "Noise pollution published in 2001"

Chronic aircraft noise exposure, stress responses, mental health and cognitive performance in school children.

Abstract: Background. 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.Methods. The cognitive performance and health of 340 children aged 8–11 years attending four schools in high aircraft noise areas (16h outdoor Leq>66dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16h outdoor Leq<57dBA). Mental health and cognitive tests were group administered to the children in the schools. Salivary cortisol was measured in a subsample of children.Results. Chronic aircraft noise exposure was associated with higher levels of noise annoyance and poorer reading comprehension measured by standardized 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.Conclusions.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.

Community noise exposure and stress in children

Abstract: Although accumulating evidence over the past two decades points towards noise as an ambient stressor for children, all of the data emanate from studies in high-intensity, noise impact zones around airports or major roads. Extremely little is known about the nonauditory consequences of typical, day-to-day noise exposure among young children. The present study examined multimethodological indices of stress among children living under 50 dB or above 60 dB (A-weighted, day-night average sound levels) in small towns and villages in Austria. The major noise sources were local road and rail traffic. The two samples were comparable in parental education, housing characteristics, family size, marital status, and body mass index, and index of body fat. All of the children were prescreened for normal hearing acuity. Children in the noisier areas had elevated resting systolic blood pressure and 8-h, overnight urinary cortisol. The children from noisier neighborhoods also evidenced elevated heart rate reactivity to a discrete stressor (reading test) in the laboratory and rated themselves higher in perceived stress symptoms on a standardized index. Furthermore girls, but not boys, evidenced diminished motivation in a standardized behavioral protocol. All data except for the overnight urinary neuroendocrine indices were collected in the laboratory. The results are discussed in the context of prior airport noise and nonauditory health studies. More behavioral and health research is needed on children with typical, day-to-day noise exposure.

The West London Schools Study: the effects of chronic aircraft noise exposure on child health.

Abstract: Background. Previous field studies have indicated that children's cognitive performance is impaired by chronic aircraft noise exposure. However, these studies have not been of sufficient size to account adequately for the role of confounding factors. The objective of this study was to test whether cognitive impairments and stress responses (catecholamines, cortisol and perceived stress) are attributable to aircraft noise exposure after adjustment for school and individual level confounding factors and to examine whether children exposed to high levels of social disadvantage are at greater risk of noise effects. Methods. The cognitive performance and health of 451 children aged 8-11 years, attending 10 schools in high aircraft noise areas (16 h outdoor Leq > 63 dBA) was compared with children attending 10 matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Results. Noise exposure was associated with impaired reading on difficult items and raised annoyance, after adjustment for age, main language spoken and household deprivation. There was no variation in the size of the noise effects in vulnerable subgroups of children. High levels of noise exposure were not associated with impairments in mean reading score, memory and attention or stress responses. Aircraft noise was weakly associated with hyperactivity and psychological morbidity. Conclusions. Chronic noise exposure is associated with raised noise annoyance in children. The cognitive results indicate that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult cognitive tests in children.

Optimization of Noise Abatement Departure Trajectories

Abstract: This paper describes the development of a new tool that offers significant capabilities for the analysis and design of noise abatement procedures at any given airport. The proposed tool combines a noise model, a geographic information system and a dynamic trajectory optimization algorithm. The optimization algorithm essentially modifies routings and flightpaths such as to minimize the noise impact in the residential communities surrounding the airport, while satisfying all imposed operational and safety constraints. Numerical examples, involving departure trajectories from Amsterdam Airport Schiphol, are included to demonstrate the effectiveness and flexibility of the developed tool. Although the results obtained to date are for departure flights only, the employed methodology tool holds out equal promise for application to approach trajectories. In the numerical examples the characteristics of a Boeing 737-300 aircraft are used.

Occupational noise exposure and hearing loss of workers in two plants in eastern Saudi Arabia

Abstract: Objective: To determine the prevalence of hearing loss associated with occupational noise exposure and other risk factors. Design: A cross-sectional study involving 269 exposed and 99 non-exposed subjects (non-industrial noise exposed subjects) randomly selected. Current noise exposure was estimated using both sound level meter and noise-dosimeter. Past noise exposure was estimated by interview questionnaire. Otoscopic examination and conventional frequency (0.25–8 kHz) audiometry were used to assess the hearing loss in each subject. Results: 75% (202 subjects) from the exposed group were exposed to a daily Leq above the permissible level of 85 dB(A) and most (61%) of these did not and had never used any form of hearing protecion. Hearing loss was found to be bilateral and symmetrical in both groups. Bivariate analysis showed a significant hearing loss in the exposed vs non-exposed subjects with a characteristic dip at 4 kHz. Thirty eight percent of exposed subjects had hearing impairment, which was an 8-fold higher rate than that found for non-exposed subjects. Multivariate analysis indicated exposure to noise was the primary, and age the secondary predictor of hearing loss. Odds of hearing impairment were lower for a small sub-group of exposed workers using hearing protection (N=19) in which logistic regression analysis showed the probability of workers adopting hearing protective devices increased with noise exposure, education, and awareness of noise control. Hearing loss was also greater amongst those who used headphones to listen to recorded cassettes. Conclusion: Gross occupational exposure to noise has been demonstrated to cause hearing loss and the authors believe that occupational hearing loss in Saudi Arabia is a widespread problem. Strategies of noise assessment and control are introduced which may help improve the work environment.

Use of poisson regression and box-jenkins models to evaluate the short-term effects of environmental noise levels on daily emergency admissions in Madrid, Spain.

Abstract: The relationship between environmental factors and hospital admissions has usually been analysed without taking into account the influence of a factor closely related to traffic in big cities, that is, environmental noise levels. We analysed the relationship between environmental noise and emergency admissions, for all causes and specific causes in Madrid (Spain), for the study period 1995–1997, using two statistical methods for the analysis of epidemiological time series data: Poisson autoregressive models and Box–Jenkins (ARIMA) methodology. Both methods produce a clear association between emergency admissions for all and specific causes and environmental noise levels. We found very similar results from both methods for all and circulatory causes, but slightly different for respiratory causes. Around 5% of all emergency admissions can be attributed to high noise levels, with a lower figure for specific causes. Current levels of environmental noise have a considerable epidemiological impact on emergency admissions in Madrid. A reduction of environmental noise levels could be accompanied by a possible reduction in the number of emergency admissions.

An Updated Catalog of 521 Social Surveys of Residents' Reactions to Environmental Noise (1943-2000)

Abstract: This report describes all social surveys of residents' reactions to environmental noise in residential areas that have been located in English language publications from 1943 to December of 2000. A total of 521 surveys are described. The surveys are indexed by country, noise source, and date of survey. The publications and reports from each survey are listed in a bibliography.

Acoustic impedance measurement with grazing flow

Abstract: Lasting increasing of air traffic will only be feasible if noise pollution near airports, due to aircraft flyover, is significantly reduced. Among acoustic emissions from the aircraft, engine noise, and particularly fan noise, is a preponderant source. In order to reduce this noise, the nacelle is lined with absorbing materials made of a thin layer (such as perforated plate) bounded to partitioned air cavities. These treatments are submitted to high sound pressure levels (up to 160 dB) and high flow Mach numbers (up to 0.7). The key design parameter is the acoustic impedance of treatment panels, which depends on sound frequency, sound pressure level and flow Mach number. Acoustic impedance properties are mainly quantified by semi or totally empirical formulas, which depend on the experimental set-up used and are specific for each type of tested layer. Therefore, EADS acoustic laboratory has got an experimental set-up measuring acoustic impedance of liners used on Airbus aircrafts. This paper presents some of existing models for perforated plates impedance, describes the experimental set-up used and shows some results that are compared with empirical models from literature. It is shown that models valid up to Mach 0.2 seem to be valid up to Mach 0.6.

Controller design for active noise cancellation headphones using experimental raw data

Abstract: This work presents a practical method of designing controllers for active noise cancellation (ANC) headphones. Without attempting system identification and perturbation modeling, the headphone system is directly described by a set of frequency-response data. In frequency domain, the controller synthesis problem is formulated as a constrained optimization problem, where the H/sub 2/ performance objective is minimized with various frequency-dependent constraints. The fixed-order robust controller is thus designed to achieve maximum noise attenuation with acceptable stability margins. Further, the method is able to accurately constrain noise amplification outside the control bandwidth due to waterbed effect of the nonminimum phase plants. This feature is very important for the ANC design to maintain an overall quality of noise reduction.

School children's travel patterns: a look back and a way forward

Abstract: A study on the recent trends in school travel patterns and outlining a number of factors that appear to influence the increasing use of private cars for transportation is illustrated. The negative impacts of car-dependent societies are air and noise pollution, and there is also a possibility of hindering a child's personal, intellectual and psychological development.

Visualization of pass-by noise by means of moving frame acoustic holography.

Abstract: The noise generated by pass-by test (ISO 362) was visualized. The moving frame acoustic holography was improved to visualize the pass-by noise and predict its level. The proposed method allowed us to visualize tire and engine noise generated by pass-by test based on the following assumption; the noise can be assumed to be quasistationary. This is first because the speed change during the period of our interest is negligible and second because the frequency change of the noise is also negligible. The proposed method was verified by a controlled loud speaker experiment. Effects of running condition, e.g., accelerating according to ISO 362, cruising at constant speed, and coasting down, on the radiated noise were also visualized. The visualized results show where the tire noise is generated and how it propagates.

Evaluation of loudness-level weightings for assessing the annoyance of environmental noise

Abstract: Assessment of the annoyance of combined noise environments has been the subject of much research and debate. Currently, most countries use some form of the A-weighted equivalent level (ALEQ) to assess the annoyance of most noises. It provides a constant filter that is independent of sound level. Schomer [Acust. Acta Acust. 86(1), 49–61 (2000)] suggested the use of the equal loudness-level contours (ISO 226, 1987) as a dynamic filter that changes with both sound level and frequency. He showed that loudness-level-weighted sound-exposure level (LLSEL) and loudness-level-weighted equivalent level (LL-LEQ) can be used to assess the annoyance of environmental noise. Compared with A-weighting, loudness-level weighting better orders and assesses transportation noise sources, sounds with strong low-frequency content and, with the addition of a 12-dB adjustment, it better orders and assesses highly impulsive sounds vis-a-vis transportation sounds. This paper compares the LLSEL method with two methods based on loudness calculations using ISO 532b (1975). It shows that in terms of correlation with subjective judgments of annoyance—not loudness—the LLSEL formulation performs much better than do the loudness calculations. This result is true across a range of sources that includes aircraft, helicopters, motor vehicles, trains, and impulsive sources. It also is true within several of the sources separately.

Environmental Urban Noise

Abstract: Introduction Physical Assessment And Rating Of Urban Noise: Physical Properties of Sound Scales and Ratings Measurement Instrumentation Noise Surveys Effects Of Noise On Health: Mechanisms and Types of Noise Health Effects Sleep Disturbance by Noise Pathological Non-Auditory Effects of Noise Community Response To Environmental Noise: Causal Linkage between Exposure and Annoyance Moderators of Annoyance Community Actions Against Noise Prediction Of Urban Noise: Sound Power and Directivity Pattern of Noise Sources Outdoor Sound Propagation Sources and Prediction of Urban Noise Methods for Reducing Urban Noise Urban Noise Evolution in Our Cities Urban Noise Control: Road Traffic, Aircraft, and Railway Noise Control Acoustical Insulation of Buildings Noise Control Regulations Economic Instruments

Urban noise--a need for acoustic planning

Abstract: The noise status of growing urban centres of the country are very much required to develop acoustic design and planning guidelines for various land use classification. An attempt in this direction has been made by measuring noise equivalent levels for cities like Delhi, Jamshedpur, Dehradun and Nagpur. The choice of Ldn (Day-Night noise level) which is a better descriptor of noise quality provides an interesting status of noise in these urban centres. It has been observed that maximum percentage of areas in Delhi and Jamshedpur fall under moderately severe to very severe noisy conditions as compared to Dehradun and Nagpur on the noise rating scale. Ways and means are also considered for mitigation of noise.

Modeling Noise at Elevated Highways in Urban Areas: A Practical Application

Abstract: Traffic noise along highways is continuously increasing; with the projected growth in future traffic use, particularly near developing urban areas, it will not cease to increase. As a result, highway noise impacts are expected to be significant and mitigation strategies will undoubtedly be required. This paper presents a noise impact analysis along a coastal stretch of highway that forms the major entrance into the greater Beirut metropolitan area. Geometric layout includes a proposed 13 km elevated highway-viaduct with underlying service roads running parallel to an existing 4 × 4-lane highway currently accommodating an average daily traffic (ADT) volume of about 160,000 vehicles per day. The proposed viaduct is planned to be a BOT (build-operate-transfer) project and thus includes two toll plazas and three interchanges. Traffic flow characteristics including volumes, vehicular classification, and travel speeds were defined along the proposed coastal highway. Sensitive noise receptors were identified and noise measurements were taken during the noisiest periods. The FHWA traffic noise model was used to simulate base year and future noise exposure of adjacent land uses. The model was calibrated using the combination of field measurements and model predictions. Noise mitigation strategies were defined as well as the locations where they were deemed appropriate. The model was used to evaluate the efficacy of the proposed mitigation measures in satisfying absolute and relative noise-abatement criteria. Finally, the feasibility of implementation of relevant mitigation measures is discussed within the site-specific constraints.

Study of Noise Barrier Life-Cycle Costing

Abstract: A life-cycle cost model for noise barrier walls was developed based on survey data and field observations. The model includes all costs required to construct the noise barriers and uses service-life estimates based on field observations and surveys. The results indicate that earth berms represent the lowest cost alternative and metal barriers with absorptive panels are the most expensive. The life-cycle costs of wood, concrete, Carsonite, and Durisol fall within a relatively narrow range near $323/m2 ($30/ft2), approximately twice the cost of earth berms. A sensitivity analysis of the model indicated that the two most important variables are initial construction cost and service life. The difficulty in obtaining data is the primary reason many state transportation departments do not use life-cycle cost analysis to select noise barrier materials. Because of the importance of the costs associated with the frequency of maintenance and replacement, and the difficulty in obtaining reliable data, life-cycle cos...

Noise pollution: a study of noise levels in the operation theatres of a general hospital during various surgical procedures.

Abstract: Noise, defined as any unwanted or undesirable sound, is a known environmental pollutant and health hazard. Sound levels during the entire surgical procedures were measured in the operation theatres (OTs) of a general hospital in Delhi, using a sound level meter, B & K 2209, on the dB(A) scale. The sound levels were found to be higher as compared to the recommended international standands. The noise was contributed mainly by doors, trolleys, equipment and alarms and the incessant conversation among the operation theatre (OT) staff. It is well documented that noise is stressful eliciting changes in the autonomic nervous system, impairing mental faculties and producing masking that could affect the staff and the conscious patient alike, leading to decreased work performance and increased anxiety respectively. Better acoustic designing and maintenance of equipment together with an increased awareness of the OT staff towards this vital factor of work environment may effectively reduce the noise pollution in OTs.

Fuzzy modeling of traffic noise annoyance

Abstract: This paper presents a fuzzy rule-based model for the prediction of traffic noise annoyance. Several inference schemes are compared for their performance in prediction capabilities as well as in speed. It is shown that the fastest implementation does an equally good job, after optimization of certainty degrees attached to the rules. For this optimization, a genetic algorithm is applied.

Les nuisances sonores dans la ville

Abstract: Noise is responsible for cochlear and general damages. Hearing loss and tinnitus greatly depend on sound intensity and duration. Short-duration sound of sufficient intensity (gunshot or explosion) will not be described because they are not currently encountered in our normal urban environment. Sound levels of less than 75 d (A) are unlikely to cause permanent hearing loss, while sound levels of about 85 d (A) with exposures of 8 h per day will produce permanent hearing loss after many years. Popular and largely amplified music is today one of the most dangerous causes of noise induced hearing loss. The intensity of noises (airport, highway) responsible for stress and general consequences (cardiovascular) is generally lower. Individual noise sensibility depends on several factors. Strategies to prevent damage from sound exposure should include the use of individual hearing protection devices, education programs beginning with school-age children, consumer guidance, increased product noise labelling, and hearing conservation programs for occupational settings.

Mitigation of Community Noise Impacts from Nighttime Construction

Abstract: Construction activities have the potential to generate a significant amount of noise that can impact the surrounding community when construction occurs near where people live or work. In the past, construction noise was often considered to be a temporary nuisance that was unavoidable and that communities would have to live with in the interest of progress. However, with the increased concern about environmental issues and the proliferation of long-term mega-projects in recent years, the effects of construction noise can no longer be ignored. This is particularly true for construction that takes place during the more sensitive nighttime hours when background noise levels are lower and people are trying to relax at home; noise that people may tolerate during the day will often be considered unacceptable at night. Unfortunately, nighttime construction is becoming ever more prevalent, particularly for transportation projects where daytime disruption of highways, airports and railways must be avoided. In an effort to help project owners, engineers and contractors deal with this problem more effectively, this paper provides a review of practical approaches for mitigating community noise impacts from nighttime construction and presents illustrative examples from specific projects. Various mitigation methods are discussed, including noise control at the source (e.g. equipment noise limits, substitutions and operational restrictions), transmission path controls (e.g. equipment relocation and sound barriers) and noise control at the receiver (e.g. building sound insulation and temporary resident relocation). However, it is most important that potential construction noise problems be identified in the planning and design phases of the project so that appropriate mitigation measures can be specified proactively, prior to the start of construction. Good community relations and communication are also essential in mitigating nighttime noise problems, along with effective monitoring and complaint response mechanisms during construction.

A reconnaissance of 'traffic noise pollution in the city of Patna'.

Abstract: The noise generated from traffic is a major source of environmental pollution, which is substantiated by the results of continuous monitoring of equivalent noise levels (Leq) at a number of sensitive, residential, commercial and industrial areas during day and night in 1999. The existing noise pollution status of Patna urban environment with emphasis on objective measurement is reported. The data were compared with the published data of other towns and cities and the possible factors responsible for change in the noise levels are discussed.

Assessment of Training Noise Impacts on the Red-Cockaded Woodpecker: 2000 Results

Abstract: : It is estimated that nearly a quarter of the remaining Red-cockaded Woodpecker (RCW) population resides on 16 military installations in the southeastern United States. Such a close association has led to increased conflicts between TES conservation requirements and the military's mission of maintaining a high degree of combat readiness. Increased importance has been placed on determining how noise affects these species. The primary research objective of this multiyear study is to determine the impact of certain types of training noise on the endangered RCW. A second objective is to develop and disseminate cost-effective techniques for documenting the effects of training noise on TES populations. During this third year of study of the impacts of training noise on the RCW, we observed and documented experimental training noise events and the resulting RCW responses under realistic conditions. Both proximate response behavior and nesting success were measured. We also observed RCW behavior and nesting success for groups where noise stimuli were absent or minimal, to provide an undisturbed behavior baseline to judge response and impact against. No significant differences in nesting success or productivity were found between experimentally disturbed and relatively undisturbed RCW groups.

The evaluation of sound level in dental practice

Abstract: Noise pollution is one of the most important problems of the contemporary world Dentistry is one of the most affected areas because the activity in a dental practice involves the use of different devices that generate noise The purpose of our study is to evaluate the sound level in a dental practice with 4 dental units using a complex system, which comprises: a Sound Blaster Live 51, a Dual microphone, a PC and special software for the acquisition and data analysis The sound level detected by us is similar with the data from the international literature with some particular aspects and suggests that the dental practice is a noise polluted environment although most of the sound levels are beneath the damaging noise level for the human ear (85 dB)

ISO 1996 "Acoustics - Description and measurement of environmental noise" round robin testing

Abstract: The CSA 107.53 Working Group of the Industrial Noise Subcommittee of the Canadian Standards Association has been actively involved in the endorsement of ISO 1996 Standard "Acoustics-Description and Measurement of Environmental Noise" in Canada. Prior to endorsing methods to assess environmental noise and predict the potential annoyance response of a community to outdoor long term noise exposure, the working group conducted a round robin testing to determine if it could be applied consistently in the Canadian context. Each of the seven round robin participants was instructed to use the measurement equipment and techniques they would normally use in assessing environmental sound. Results were measured and reported in terms of the L LM (Logarithmic Mean Impulse Sound Level) and the Case 1 Rating Level.

Noise pollution in kerman-iran

Abstract: Noise is defined as unwanted or objectionable sound. Human susceptibility to noise varies in terms of intensity, altitude, timbre of sound, personal sensibility, age, and history of ear disorder. Noise pollution which is the result of heterogeneous and uncontrolled developments of cities is one the serious problems in large cities of Iran. Although noise pollution in Kerman (located in southeast of Iran) is not as serious as that of large cities in Iran, it can be considered as one of the elements which have changed Kerman's life pattern. In this study, conducted in 1999, in order to assess noise pollution level in Kerman, 13 stations were selected and the levels of Lmax, LAV, L99, L90, L50, L10 were measured daily for 156 days. Results, in all stations, indicated that sound level in Kerman exceeds national standard level and WHO guidelines. Therefore, it is essential to take some actions in order to control Kerman noise pollution with some undesirable impacts.