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RELIABILITY ANALYSIS OF TRAFFIC NOISE ESTIMATES IN HIGHWAYS OF TEHRAN BY MONTE CARLO SIMULATION METHOD  [PDF]
I. Alimohammadi, P. Nassiri, M. Behzad and M. R. Hosseini
Iranian Journal of Environmental Health Science & Engineering , 2005,
Abstract: This study was aimed to examine the reliability of traffic noise estimate and measurement techniques in highways of Tehran, capital of Iran. The multiple regressions showed that the traffic flow and the distance from the effective source position are the most important factors to estimate the L10 (1h). Traffic flow, traffic composition in terms of heavy vehicles and traffic speed are identified as the key factors influencing the generation of traffic noise. The new equations for estimating the noise descriptor L10 was calibrated on the basis of noise measurements. The effects of the key factors on L10 (1h) were examined by the sensitivity analysis and it was found that traffic flow, distance from the effective source position, traffic composition and traffic speed had the most sensitivity on traffic noise, respectively. The probability distribution for each of the key factors was derived with the use of the survey data. The reliability of the traffic noise estimates was obtained from the combined probability distribution of the key factors by Monte Carlo simulation method. This study showed that there was no significant difference between estimated noise by calibrated CoRTN calculation of road traffic noise and measured noise level. The reliability analysis gives the traffic noise estimates with a particular probability or vice versa.
ROAD TRAFFIC NOISE IN DOWNTOWN AREA OF TEHRAN  [PDF]
N. Mansouri, M. Pourmahabadian, M. Ghasemkhani
Iranian Journal of Environmental Health Science & Engineering , 2006,
Abstract: Noise pollution is a major problem for the quality of life in urban areas. The present study was conducted to determine the noise levels of road traffic at central area of Tehran. It focused on one of the busy and crowded square along with its 7 connecting streets, which had a heavy traffic and located in the downtown of the city. Total of 115 measuring points were selected along the roads, pavements and in the shopping areas to adequately represent the different acoustically commercial situations. The measuring points were divided in to 4 site-groups namely; Street, Pavement, Shop and Barrier each with 60, 40, 10, and 5 measuring points respectively. The measurements were carried out during a full week days started on Saturday morning and end on Friday evening. The A-weighted continuous equivalent sound level values, LAeq; LA max; LA min ; and the statistical levels: L1, L10, L50, L90 and L99 as well as the octave band center frequencies sound pressure levels were manually measured at each point separately. The mean values of LAeq for Street, Pavement, Shop and Barrier site groups were 78.5, 73.3, 68.7 and 70.8 dBA respectively and the overall mean of LAeq was 74.7 dBA. The statistical test (p<0.01) showed that the mean values for LAeq in all site groups as well as the overall mean value were higher than 65 dBA, which is the daytime governmentally prescribed noise limit for commercial areas. Comparing the individual measurements has also shown the 86.6% exceeded values from 65 dBA. The highest mean noise level in center frequencies upper than 1000 Hz was 71.5 dBA which was observed in the Street site group and the lowest one was 43.2 dBA in the Shop site group at 8000Hz center frequency. The corresponding values for the center frequencies lower than 1000 Hz were 78.2 and 66.1dBA at 63 and 500 Hz which were also observed in the Street and Shop site groups respectively. It can be concluded that the downtown of the city is environmentally noise polluted and the road traffic is the major source of it. Noting the noise emission standards, police control, and promoting the citizens awareness about the high level noise risk may help to relieve the noise problems in the city.
3D Analysis and Investigation of Traffic Noise Impact from Hemmat Highway Located in Tehran on Buildings and Surrounding Areas  [PDF]
Hamid Reza Ranjbar, Ali Reza Gharagozlou, Ali Reza Vafaei Nejad
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.44037
Abstract: This study analyzes and investigates the impact of traffic noise on high rise buildings and surrounding areas by the side of Hemmat Highway that links west of Tehran to the east. In this study, a 3D traffic noise simulation model is applied on a GIS system. Visualized noise levels are formulated by the proposed model for noise mapping on all surfaces of the buildings and surrounding ground in a 3D platform. The investigation shows that there is a high traffic noise impact on the foreground and front facades of buildings, rendering these areas unsuitable for residential purposes. The ground area by the sides of buildings and the building side panels receive a lower noise impact. Most of these areas are still not acceptable for residential and even commercial use, only the back yards and back panels, have the lowest traffic noise impact. It also shows that the building height is not an effective factor for reducing motorway noise on the upper part of the building. Finally, construction cantilever barriers with a height of seven meters, close to the outer edge of the highway was presented as an effective way to reduce noise within the allowable range of noise pollution for commercial and residential purposes.
FACTORS AFFECTING ROAD TRAFFIC NOISE ANNOYANCE AMONG WHITE-COLLAR EMPLOYEES WORKING IN TEHRAN  [PDF]
*1I. Alimohammadi, 2P. Nassiri, 3M. Azkhosh, 4M. Hoseini
Iranian Journal of Environmental Health Science & Engineering , 2010,
Abstract: The effect of personal and attitudinal factors, noise level, hearing status and psychological traits on traffic-related noise annoyance among white-collar employees working in Tehran has been carefully analyzed. This survey has been conducted by interviewing 495 citizens working in non-manufacturing industries in Tehran, using questionnaires, Weinstein noise sensitivity scale, Beck’s depression, Buss and perry’s aggression, Zung’s anxiety, job satisfaction and Eysenc’s personality inventory. These citizens were office workers or store employees. Noise annoyance was determined both by numerical-based questionnaire criterion and by verbal index. Personal information, attitudinal factors and hearing conditions were determined using a general questionnaire. The amount of workplace noise the participants were exposed to was directly measured at their workplaces. It was revealed that among personal factors, age (p=0.030), marital status (p=0.004), residential period (p=0.001) and wealth (p=0.04) were related to noise annoyance. Attitudinal factors including sensitivity to noise (p=0.001), individual’s opinion on the need to control the noise (p=0.000) and individuals’ assessment of the amount of the workplace ambient noise (p= 0.000) were found to have relationship with noise annoyance. No meaningful relationship was seen between the equivalent noise level (p=0.879) and statistical noise level of L90 (p=0.909). The present study revealed that among all effective factors involved in noise annoyance, attitudinal factors had the most significant role in this regard.
Application of GIS in Urban Traffic Noise Pollution
Ali Asghar Alesheikh,Manouchehr Omidvari
International Journal of Occupational Hygiene , 2010,
Abstract: Large urban areas are facing growing problems of noise pollutions. Geospatial Information Systems (GIS) can conveniently be adapted to gather, analyze and present noise information. GIS can also be extended to answer to user specific problems through deterministic and statistics models. The objectives of this research were to measure urban traffic noise levels, analyze temporal and spatial dynamics of urban traffic-induced noise pollution in the first districted of Tehran estimate the noise for pollution concentration, assess the results of Federal Highway Administration Traffic Noise Model (FHWA-TNM) and Iranian Traffic Noise Predictor (ITNP); and represent them in a GIS environment. Measurements were done at the traffic peak time and also when the traffic was at its minimum, during three successive months. In this study, Leq, L10, L50, L90, Lmax and Lmin were gathered. The results demonstrated that most of commercial and residential regions surrounding the main streets are suffering from sever noise pollution. Processed data, spatial analysis and models are integrated within the framework of ArcGIS software environment, providing adequate tools to address noise issues. The assessment showed that the issue of noise pollution is currently ignored in urban regulations concerning environmental quality.
A COMPACT MODEL FOR PREDICTING ROAD TRAFFIC NOISE  [PDF]
R. Golmohammadi ? M. Abbaspour ? P. Nassiri ? H. Mahjub
Iranian Journal of Environmental Health Science & Engineering , 2009,
Abstract: Noise is one of the most important sources of pollution in the metropolitan areas. The recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable us to predict noise level from fundamental variables. Traffic noise prediction models are required as aids in the design of roads and sometimes in the assessment of existing, or envisaged changes in, traffic noise conditions. The purpose of this study was to design a prediction road traffic noise model from traffic variables and conditions of transportation in Iran.This paper is the result of a research conducted in the city of Hamadan with the ultimate objective of setting up a traffic noise model based on the traffic conditions of Iranian cities. Noise levels and other variables have been measured in 282 samples to develop a statistical regression model based on A-weighted equivalent noise level for Iranian road condition. The results revealed that the average LAeq in all stations was 69.04± 4.25 dB(A), the average speed of vehicles was 44.57±11.46 km/h and average traffic load was 1231.9 ± 910.2 V/h.The developed model has seven explanatory entrance variables in order to achieve a high regression coefficient (R2=0.901). Comparing means of predicted and measuring equivalent sound pressure level (LAeq) showed small difference less than -0.42 dB(A) and -0.77 dB(A) for Tehran and Hamadan cities, respectively. The suggested road traffic noise model can be effectively used as a decision support tool for predicting equivalent sound pressure level index in the cities of Iran.
Nuisance Caused by Aircraft Noise in the Vicinity of Tehran International Airport
Khodabakhsh Karami,Stan Frost
Audiology , 1999,
Abstract: Noise measurement and social questionnaire surveys in three residential areas around Mehrabad International Airport (Tehran, Iran) were based upon randomly selected dwellings in each area. A total of 193 individuals responded and many are annoyed and dissatisfied with aircraft noise and in consequence they would like to move. Aircraft noise is the strongest negative environmental factor affecting the residents in the vicinity of Mehrabad Airport and it could be a hazard for their health.
Attitudes of Community to Urban Traffic Noise in Morogoro, Tanzania
MS Gaganija, SL Mkoma, ES Lema
Ethiopian Journal of Environmental Studies and Management , 2012,
Abstract: Traffic noise is a major environmental source of pollution both in developed and in developing countries. This study was carried out in Morogoro municipality, located about 200 km west of Dar es Salaam the business capital of Tanzania. Total of 16 measuring points were selected along main roads and A-weighted continuous equivalent sound level meters was used for measurement of noise level. The average noise equivalent level at measured points varied between 51.1 to 75.1 dBA. The results established the fact that noise levels are more than the acceptable limit of 55 dBA, which is the daytime governmentally prescribed noise limit for residential-commercial areas. This study also describes the reaction of the Morogoro residents to environmental noise pollution. A total of 200 questionnaires were processed. The results of the interview questionnaire revealed that the main isolated noise source was traffic (51%) and street noise (29%). About 45% of the respondents classified the noise in their street as “high”; and that noise bother 77% of the respondent more in daytime. The main impacts of exposure to noise were reported to be headache, hearing problem, sleeplessness, difficulty to concentrate and conversation disruption. This study recommends raising community awareness on noise pollution, structural management, traffic management and enforcement of laws and regulations so as to control noise pollution.
Equivalent Noise Level Response to Number of Vehicles: A Comparison between a High Traffic Flow and Low Traffic Flow Highway in Malaysia  [PDF]
Herni Halim
Frontiers in Environmental Science , 2014, DOI: 10.3389/fenvs.2014.00013
Abstract: Although much research on road traffic noise has found that noise level increase are influenced by driver behaviour and source- receiver distance, little attention has been paid to the relationship between noise level and total number of vehicles on the road. In this study, five days measurement of noise level during peak hour and off peak hour has been carried out at two types of highways; high traffic flow highway (Sungai Besi Expressway)and low traffic flow highway(Duke Highway). Simultaneously, the number of vehicles passing the measurement point were recorded for every 15 minutes. Findings indicated that heavy traffic flow highway recorded higher noise level compared to low traffic flow highway. It was due to the higher number of vehicles on the heavy traffic flow highway than low traffic flow highway. Other than that, certain particular number of vehicles, noise level keeps stabilization.
Road Traffic Noise Model  [cached]
R Golmohammadi,M Abbaspour,P Nassiri,H Mahjub
Journal of Research in Health Sciences , 2011,
Abstract: Background: The recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable to predict noise level from fundamental variables. Traffic noise prediction models are required as aids for designing roads and highways. In addition, sometimes are used in the assessment of existing or envisaged changes in traffic noise conditions. In this paper a statistical modelling approach has been used for predicting road traffic noise in Iranian road conditions. Methods: The study was performed during 2005-2006 in Hamadan city, in the west of Iran. The data set consisted of 282 noise measurements. The entire data set was utilized to develop a new model for Iranian condition using regression analysis. Result: The developed model has twelve explanatory variables in order to achieve a proper fit for measured values of Leq (r2= 0.913). Conclusion: The proposed road traffic noise model can be effectively used as a decision support tools for prediction of traffic noise index of Leq(30min), in Iran's cities.
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