Environmental noise pollution in the city of Curitiba, Brazil

The City of Amman, Jordan, has been subjected to persistent increase in road traffic due to overall increase in prosperity, fast development and expansion of economy, travel and tourism. This study investigates traffic noise pollution in Amman. Road traffic noise index L10(1 h) was measured at 28 locations that cover most of the City of Amman. Noise measurements were carried out at these 28 locations two times a day for a period of one hour during the early morning and early evening rush hours, in the presence and absence of a barrier. The Calculation of Road Traffic Noise (CRTN) prediction model was employed to predict noise levels at the locations chosen for the study. Data required for the model include traffic volume, speed, percentage of heavy vehicles, road surface, gradient, obstructions, distance, noise path, intervening ground, effect of shielding, and angle of view. The results of the investigation showed that the minimum and the maximum noise levels are 46 dB(A) and 81 dB(A) during day-time and 58 dB(A) and 71 dB(A) during night-time. The measured noise level exceeded the 62 dB(A) acceptable limit at most of the locations. The CTRN prediction model was successful in predicting noise levels at most of the locations chosen for this investigation, with more accurate predictions for night-time measurements.

Evaluation of traffic noise pollution in Amman, Jordan.

Two models for predicting in-city road-traffic noise pollution of Mashhad have been obtained. Traffic volume, composition, and speed have been chosen as model's parameters. Vehicles were classified into light cars and medium and heavy trucks. Reference emission level of each group was determined experimentally based on perpendicular propagation from central lane of traffic road. Simultaneous measurements of noise level and vehicle flow and composition were done. Two mathematical models have been proposed by the use of genetic algorithms which can be used for calculating L"e"q. These models have been validated against noise data. Subsequently, measured traffic noise has been compared with calculated ones, using developed models, and a relatively good agreement has been obtained among them. The models are found accurate within +/-1% and can be used for flat road noise prediction.

Modeling of road-traffic noise with the use of genetic algorithm

Wind turbines emit low frequency noise (LFN) and large turbines generally generate more LFN than small turbines. The dominant source of LFN is the interaction between incoming turbulence and the blades. Measurements suggest that indoor levels of LFN in dwellings typically are within recommended guideline values, provided that the outdoor level does not exceed corresponding guidelines for facade exposure. Three cross-sectional questionnaire studies show that annoyance from wind turbine noise is related to the immission level, but several explanations other than low frequency noise are probable. A statistically significant association between noise levels and self-reported sleep disturbance was found in two of the three studies. It has been suggested that LFN from wind turbines causes other, and more serious, health problems, but empirical support for these claims is lacking.

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Infrasound and low frequency noise from wind turbines : exposure and health effects

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.

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Road traffic noise in downtown area of tehran

Because of an expert’s report on the medical effects of noise on healthy adults, permissible values for mainly traffic noise have been estimated by the standard of knowledge. If the permissible values are exceeded, then preventative medical action is necessary. Below this value the probability of noise‐induced health hazards is essentially zero. The effect due to noise as a health hazard is, besides the mechanical damage of the inner ear, a psycho‐physiological deregulation which can be either indirectly due to the annoyance or directly caused by stress of the vegatative‐hormonal system. Therefore, different permissible values for annoyance, the stress on the vegetative‐hormonal system, and for the loss of hearing are suggested, for both continuous and maximum noise levels. In addition, the deregulation depends on the time of the acoustic exposure because the sensitivity to noise follows a 24‐h cycle (circadian rhythm). It is therefore necessary to give personal permissible limits for the evening noise and the nocturnal noise.

Hans‐Ulrich Balzer

Papers

Preventative medical limits for chronic traffic noise exposure