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Showing 10 results for Noise
Occupational Noise Exposure Evaluation in Drivers of Bus  Transportation of Tehran City
P Nassiri, M Monazam Esmaeelpour, A Rahimi Foroushani, H Ebrahimi, Y Salimi,
Volume 2, Issue 2 (9-2009)
Abstract

Backgrounds and Objectives: Noise in large cities is considered by the World Health Organization to be the third most hazardous type of pollution. Buses are an interesting object of study in the theme of noise pollution. They are at the same time a source of urban environmental (traffic) noise and occupational noise exposure source for drivers. The object of this study is Occupational noise exposure evaluation in drivers of bus transportation of Tehran city.
Materials and Methods: Noise levels in 90 buses were sampled in three separate sub-sample including (1)30 Ikaroos buses (2)30 Man buses (3)30 Shahab buses, which were selected by simple random sampling. Noise exposure level was normalized to a nominal 8-h working day (LEX, 8h). Simultaneous Octave Frequency Analysis were measured and sound intensity level (SIL) for bus drivers were calculated. Results, which are obtained from separate buses were compared together and too with standard levels.
Results: the normalized noise exposure levels (LEX, 8h) in Ikaroos bus drivers(82dB A) were higher than that of in in Man bus drivers (77/6dB A) and this Values were higher than that of in Shahab bus drivers(75dB A).SIL values for Ikaroos bus drivers were higher than other that of other bus drivers. Results obtained of Frequency Analysis showed that age of buses in mid frequencies ws a meaningful on noise increase.
Conclusion: Results showed that type and age of buses were effective factors in drivers. noise exposure levels (LEX, 8h), which was consistent with previous studies in this field.


Performance of PRD Welled Surfaces in T Shape Noise Barriers for Controlling Environmental Noise
M.r Monazzam, M Naderzadeh, P Nassiri, S Momen Bellah,
Volume 3, Issue 2 (7-2010)
Abstract

Backgrounds and Objectives: There is a considerable notice in the use of noise barriers in recent years. Noise barriers as a control noise solution can increase the insertion loss to protect receivers. This paper presents the results of an investigation about the acoustic efficiency of primitive root sequence diffuser (PRD) on environmental single T-shape barrier.
Materials and Methods: A 2D boundary element method (BEM) is used to predict the insertion loss of the tested barriers. The results of rigid and with quadratic residue diffuser (QRD) coverage are also predicted for comparison.
Results: It is found that decreasing the design frequency of PRD shifts the frequency effects towards lower frequencies, and therefore the overall A-weighted insertion loss is improved. It is also found that using wire mesh with reasonably efficient resistivity on the top surface of PRD improves the efficiency of the reactive barriers however utilizing wire meshes with flow resistivity higher than specific acoustic impedance of air on the PRD top of a diffuser barrier significantly reduces the performance of the barrier within the frequency bandwidth of the diffuser. The performance of PRD covered T-shape barrier at 200 Hz was found to be higher than that of its equivalent QRD barriers in both the far field and areas close to the ground. The amount of improvement compared made by PRD barrier compared with its equivalent rigid barrier at far field is about 2 to 3 dB, while this improvement relative to barrier model .QR4. can reach up to 4- 6 dB.
Conclusion: Employing PRD on the top surface of T-shape barrier is found to improve the performance of barriers compared with using rigid and QRD coverage at the examined receiver locations.


Relationship examination of noise perception, Psychological Hardiness and Mental Health with Psychological Hardiness and Mental Health with the Quality of life in Inhabitants of Rasht bustle Area
I Shakerinia,
Volume 3, Issue 4 (1-2011)
Abstract

Backgrounds and Objectives:The aim of these research is examining the relation among noise psychological stubbornness and mental health with the life quality of rasht housewives.
Materials and Methods: After measuring the amount of noise in different streets , the researcher chose randomly 50 housewives from noisy streets of Rasht , and completed the study questionnaire. Then they analyzed data with peirson correlation and regression analysis.
Results:Theresultsshowedthat there is significant of perception of noise , psychological stubbornness and mental health with the quality of life. The amount of F parameter of regression analysis at P<0/01 level was significant and 91% of variance among noise with psychological stubbornness, mental health, with the quality of common life. Among the amount of noise, psychological stubbornness and mental health , the noise perception and mental health are able to making clear the quality of housewives&apos life it means that increasing the amount variance of psychological stubbornness to equation wouldn&apost lead to increase significantly.
Conclusion: paying attention to the effectiveness variables like noise and psychological like mental health on quality of life , Societies&apos development and achievement and decreasing social services, present study suggest that all responsible organizations who work about societies&apos health are trying to set their programs forward to promote the quality of the whole society life and do this by decreasin


Occupational Noise Exposure and Hearing Loss Among Car Smoothers in Qazvin
S Ahmadi, A.a Karbord, E Einanlo, H Aubi Zade, M Zarei,
Volume 4, Issue 1 (5-2011)
Abstract

Backgrounds and Objectives:Indusrial noise exposure is the most common hazardous agent in the world.This study has been done to determine the prevalence associated with occupational noise in car smoothers at qazvin.
Materials and Methods: The study group composed of 50 subjects who were selected out of a total of 218 car smoothing workshops.Background information,exposure time and...with a questionnaire collected.Noise exposure and hearing loss were measured by noise dosimeter model CEL-280 and audiometer model OB 288 Madsen.
Results: The mean of age and work experience were 38.7 and 21.5 respectively.Noise exposure and total hearing loss were measured 98.2±3.4 dB(90-104dB) and 22.1±9.16 dB respectively. Spireman correlation was significant between right and left ears(P<0.05 ,R=0.87).Total hearing loss were measured natural(NIHL!25) in 64 percent(32 person),slight(26! NIHL!40)in 34 percent(17 person) and moderate (41! NIHL!60) in 2 percent (1 person).The most and the least hearing loss were measured 42.4(4000 HZ) and 37.1(8000 HZ) dB in left and right ear respectively. The chi square analysis was significant between hearing loss,work experience and age(P=0.015).ANOVA analysis was not significant between noise exposure and hearing loss(P=0.09).
Conclusion:Considering NIHL and severe noise exposure , the necessity for improvement of controlling and protection measures has prime importance.


Noise Pollution Evaluation in Residential and Residential- Commercial Areas in Tabriz-Iran
M Ghanbari, K Nadafi, M Mosaferi, M Yunesian, H Aslani,
Volume 4, Issue 3 (10-2011)
Abstract

Background and Objectives: Over the last three decades environmental pollutions became a more noticeable problem in all around of the world. In many countries, noise pollution as a basic problem has a great importance.Development of the city, increasing of industrial centers, increasing vehicles, other annoying noise resources and also little information about the noise pollution of Tabriz city, has led to the doing of this research.
Materials and Methods: Sampling and measuring of noise pressure levels was done 180 times According to the EPA standards, measuring was done simultaneously in two stations(commercial-residential areas), three times a day (morning 7:30 -9:30 am, midday 12:30-14:30 pm and night 19:00-21:00 pm) and 30 days in month. 
Results: Sound pressure level in both stations was higher than the standards and the highest average level with 71.4 db was recorded in Raste-koche station at midday. Also lowest calculated average value with 68.5 db was measured in Golbad station at the morning time that is 8.5 db higher than the standards.
Conclusion: Average measured sound pressure level in two stations was higher than the standards. The results show that Tabriz has a noise pollution in commercial and residential - commercial areas. It is suggested that other noise pollution resources identified and the proper management actions for its reduction be done.


Introducing the Standard and Chart to Measure and Control the Motorcycle Noise Level
P. Nassiri, M.r Monazzam, K Azam, N Hosseini Gousheh, S Farhang Dehghan,
Volume 4, Issue 4 (3-2012)
Abstract

Background and Objectives: Sound of motorcycles plays an important role in noise pollution in big cities. This is due to the lack of national law or standards to control the noise of domestic and also imported motorcycles. This study tries to introduce a practical limit value in different stage of motorcycle life cycle by assessing their noise pollution.
Materials and Methods: First the motorcycles noise standards at different countries were studied and they were compared with the results from noise level of 622 motorcycles in 3 different groups. The sample volume in each group corresponds to the amount of their annual production rate. Then using statistical tests, a limit was determined in which 90% of the domestic motorcycles can be covered. The limit is proposed as the standard for domestic motorcycle noise.
Results: The limit for motorcycles of groups 1, 2 and 3were 84, 86 and 87 dB (A) ,respectively in the TA stage. For the COP stage (Conformity of Production), the limit increases according to certain formula. In the end, a flowchart was proposed as a standard method for measuring the sound of motorcycles in the TA and COP stages was proposed.
Conclusion: Noise level of the domestic motorcycles is at least 9 dB (A) higher than the noise limit value of European motorcycle. If European limit value is considered for producing the national motorcycle, 90% of them will get out of production cycle and this would not be practical.


Noise Pollution Evaluation of City Center of Zanjan by Geographic Information System (GIS)
F Majidi, Y Khosravi,
Volume 9, Issue 1 (6-2016)
Abstract

Background and Objective: The aim of  noise control in a community is to improve its management in the community, because the traffic noise can affect neighboring residential areas. Well-planned noise management can eliminate this major and harmful component issue, which is one of the stresses of urban life on human health. However, before planning to decrease urban noise, it is necessary to determine the very noisy areas in a given city. Therefore, the objective of this study was to measure the main noise indices at the noisy areas of Zanjan City, Iran.

Materials and Methods: This study was performed in the central area of Zanjan City, with heavy traffic. For this purpose, the equivalent sound level (Leq), the day-night sound level (Ldn), the day-evening-night sound level (Lden), the noise pollution level (NP) and the traffic noise index (TNI) were measured in 19 stations in the first half (winter and spring) of 2012. The measurements were conducted in the main streets of this area as recommended by EPA guidelines and finally the results obtained were mapped using the ArcGIS (Ver. 10.2) software. 

Results: the noise maps in GIS showed clearly the variations of Leq, Ldn, and Lden indices in the study field area. Moreover, it was found that the hourly variations of Leq, Ldn and Lden in stations are completely function of population movements and therefore traffic loads in the Zanjan city center. In addition, the extent of violation of traffic noise level from the ambient noise standard was estimated by Lden at 100% stations (greater than 55 dB). The TNI values at 67  and 100% stations  were more than 74 dB (A), but  in the evenings the TNI values at  100% of stations  were more than 74 dB (A). The NP values at 78% sampling stations were more than 80 dB  implying  traffic noise was annoying in the most stations and times.

Conclusion: Using noise maps, NP and TNI indices can help intelligent traffic control planning, because the noise maps can be used to represent the movement of people in different times and parts of a city.   


Evaluation of particulate matter (PM) and noise levels in underground terminals-Majlesi terminal of Isfahan
A Tavakoli,
Volume 11, Issue 1 (6-2018)
Abstract
Background and Objective: Air pollutants and noise level are areas of concern for public health, especially in metropolitan areas. In tunnels, underground stations and indoors with insufficient ventilation rate and noise reflection, accumulation of pollutants and noise pollution are serious problems.
Materials and Methods: The present study was conducted to evaluate the level of PM and noise level in the Majlesi terminal, located close to Imam Ali Square in Isfahan. Sampling was done in two phases, spring and summer. Samples were taken during six working days, twice a day, morning and afternoon and at traffic peaks. The effect of launching a BRT system was also evaluated. The SKC sampling pump and sound level meter of KIMO were used for the evaluation of particulate matter and noise.
Results: The results showed that the launch of a BRT system led to a change in PM concentration from 85.17 μg/m3 to 53.58 (37% reduction), however, the average value of summer noise level (78.34 dB) was higher than the average value of spring (76.23 dB). Both PM and noise levels were higher than the values of international standards of EPA and WHO guidelines. The level of PM and noise level was a function of traffic and varied during weekdays. On Thursdays and after medieval holidays, the highest level was observed. The pollution and noise levels were higher during afternoon than the morning peak hours due to the traffic and accumulation of contaminants.
Conclusion: The research revealed that indoor and underground environments are not suitable options as a parking lot or bus terminals, due to a need for mechanical ventilation, lack of adequate air circulation and sound reflection.
 

The use of geographic information systems (GIS) for assessing noise pollution in industrial workplaces: a case study of knitting industry
Mr Jelokhani-Niaraki, F Hajiloo, L Hasanzade,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Noise pollution causes many physiological, psychological, economic and social effects on human life. This issue is more important in the environment of industrial workplaces. This research aimed to adopt the functions of GIS for evaluating and spatial analysis of noises in industrial environments.
Materials and Methods: At the initial step, the spatial data for industrial halls were collected and stored as map layers into GIS database. Then, the noise pollution data sampled. The data, including the locations and values of sound pressure levels, were used for the relevant spatial analyses.
Results: The analyses included: the estimation of sound pressure levels in different areas of halls and at the given distance from machines, determination of noisy areas, development of sound noise risk map, interpolation of sound pressure level data, prioritization of the sound sources (i.e., machines) for a given point, prediction of sound pressure levels by moving machines, and optimal site selection and distribution of machines. The mean of noise pressure level was 95 dB for knitting hall,  93 dB for spinning hall 1 and 88 dB for spinning hall 2.
Conclusion: GIS plays a key role in the assessment of noise pollution in industrial workplaces. It is an appropriate tool to store, analyze, manage, and present all types of sound pressure spatial data. Specifically, the use of such system provides spatial intelligence and could help monitor, detect, control, and solve real word sound noise pollution issues.
 

Assessment of noise levels and identification of distribution pattern in elementary schools: a case study in Zanjan city
Fatemeh Mohebbian, Azadeh Tavakoli, Abdolhossein Parizanganeh, Younes Khosravi, Isa Eskandari,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective: Conversion of houses into residential towers in worn-out urban textures increases population. Schools of the vicinity would face with multiplicity and limited space for students, leading to noise pollution. The purpose of this study was to evaluate the noise levels during morning and afternoon shifts among two primary schools in Zanjan.
Materials and Methods: Measurements had been done using sound level meter, KIMO DB100. The equivalent noise level (Leq) measured during school year (2018-2019) in 10 stations. The measurements were done in three seasons (autumn, winter and spring) and in each season for two weeks. The data of the two schools were used for drawing charts and zoning by ArcGIS using IDW method. In addition, questionnaires were distributed among the teachers and school’ neighbors. The data were analyzed by SPSS software.
Results: The results showed that all the stations were tackled with noise pollution. The highest levels were related to school’s shift change and break times. The morning shift schools experienced higher levels of noise in comparison to the afternoon ones (1.87 and 2.1 dB, respectively for boys and girls). Leq values for boys’ school was 2 dB higher than that of the girls’. The noise level in the schools were 72 dB, which is 17 dB higher than the standard level 55 dB.
Conclusion: The residents living close to the schools were exposed to noise pollution for almost 10 hours a day. This could be regarded as harmful. The zoning maps showed that southwest side of the yard, adjacent to the neighboring residential buildings, had the highest levels of noise. This study demonstrated the site selection for the schools were not properly done.  Having a control strategy is needed.

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