Noise Evaluation and Survey of Effective Factors on Traffic Noise Pollution in the Golestan National Park

Among the environmental pollution sources, noise has especial importance because of physiological and psychological effects on humans. Today, traffic noise caused by vehicles is an important and common source of noise pollution. Therefore, many countries have established laws to control this problem. One of the common methods for predicting and evaluating the effects of traffic noise is application of statistical models. As the sound pressure level is measured, other variables such as number and speed of vehicles, relative humidity, temperature, length and width of the road, the sound barrier height, distance from roads, slope, wind direction, vegetation density and diversity, height of the sea level and the size should be measured for model application. Then, the average daily and nightly equivalent noise level in each of stations is compared with the sound quality standards that determine which stations have unallowable sound and therefore are need of management actions. This article reviews the relevant sources of noise pollution and examples of domestic and foreign researches.