جستجوی مقالات مرتبط با کلیدواژه « noise level » در نشریات گروه « پزشکی »

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.
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.
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.
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.

Introduction and purpose: Noise pollution is an important health problem in most industries, especially in the small inland industries. The purpose of this study was to evaluate the noise pollution in turning and polishing shops in Qom, Iran, and compare it with the sound standards in the country. In the present descriptive cross-sectional study, noise assessment was performed using the local measurements to evaluate occupational exposure with a dosimeter (CEL 320, Casella CEL, Inc., New York) in 20 turning shops and 20 polishing shops. Then, the equivalent sound balance was calculated for a work shift and compared with the sound standards In Iran. The results showed that the average equivalent sound levels in turning and polishing shops were 93.1 and 100.4 dB, which were unauthorized in comparison with the national sound standards. Furthermore, the noise pollution outside the shops was reported beyond the standards of the relevant region. It should be noted that regarding the evaluation of hearing sensitivity, 86.1% of the workers did not have a hearing test. In addition, sanitary inspections were not carried out in 83% of the shops. However, 64% of the shops were not upgraded and the participation rate of the shop owners was 53% in the improvement measures. According to noise pollution in turning and polishing shops and the effects on workers and the public, noise control methods are proposed, such as the provision of personal protective equipment, reduction of labor time, correct choice of machines, and installation of noise-reduction tools. With respect to noise pollution, the correct locating of shops and organizing noisy industries were proposed.

Safe driving requires the ability of the driver to receive the messages and complying with them. The most significant consequences of noise pollution are on the human auditory system. Disorders in the auditory system can have harmful side effects for human health. By reducing this kind of pollution in large cities, the quality of life, which is one of the biggest goals of the governments, can be considerably increased. Hence, in the present research, some parameters of vehicle tires were examined as a source of noise pollution, and the results can be taken into consideration in noise pollution reduction.
Material and Several vehicles with different tire width were selected for measuring sound level. The sound levels were measured for moving vehicles with the use of the Statistical Pass By Method (SPB, ISO 11819-1). Following sound level measurements for moving vehicles and by considering tire width, mathematical model of noise level was predicted on the basis of the obtained information and by usage of SPSS program and considering vehicle tire parameters.
The result of this study showed that the vehicle speed and tire width can affect different sound levels emitted by moving tire on road surface. The average speed of vehicles can play an important role in the noise pollution. By increasing speed, rotation of the the tires on the asphalt is increased, as it is a known factors for noise pollution. Moreover, changing the speed of vehicles is accompanied with abnormal sounds of vehicle engine. According to regression model analysis, the obtained value of R2 for the model is 0.8367 which represents the coefficient of determination.
The results suggest the main role of the vehicle speed and tire width in increasing the noise reaches to the drivers and consequent noise pollution, which demonstrates the necessity for noise control measures. According to the obtained model, it is understood that changes in noise levels and tire width are more than those of vehicles speed. The coefficient of 0.1482 for tire width, comparing to coefficient of 0.1195, shows that considering the proper tire width can be effecttive in reduction of sound level.