Influence of Meteorological Conditions on Pollutant Dispersion in Street Canyon

Vehicle exhaust pollutants has become a major source of urban air pollution and it is of great significance to study its diffusion law. This paper analyzes the factors that affect the diffusion of motor vehicle emissions in the street canyon and determines the research method of pollutant dispersion. This paper mainly simulates the influence of different wind speed and wind direction on the flow field and pollutant dispersion in the street canyon. Results show that the wind speed and wind direction has a great impact on the air flow and pollutant dispersion in the canyon. Vertical and inclined to the wind, the leeward side of the street canyons pollutant concentrations is much higher than the windward side of the concentration of pollutants, leeward pollutant concentration and the pollutant concentration of the windward side of is almost the same. The results of this paper can provide scientific basis for the control, monitoring and evaluation of urban motor vehicle emissions, and reasonable layout and planning of urban streets. (C) 2015 The Authors. Published by Elsevier Ltd.