Pollution Dispersion in Urban Street Canyons with Green Belts

Abstract

In this study, numerical simulations were used to explore the effects of roadside green belt, urban street spatial layout, and wind speed on vehicle exhaust emission diffusion in street canyon. The diffusion of different sized particles in the street canyon and the influence of wind speed were investigated. The individual daily average pollutant intake was used to evaluate the exposure level in a street canyon microenvironment. The central and leeward green belts of the road were the most conducive to the diffusion of pollutants, while the positioning of the green belts both sides of a road was least conducive to the diffusion of pollutants. Pollutant levels increased with increasing canopy height, canopy width, and decreasing tree spacing, with optimal values of 12m, 7 m, and 0.4 H, respectively. This provides protection from pollution for low-rise residents and pedestrians. The results presented here can be used to improve the air quality of the street microenvironment and provide a basis for the renovation of old street buildings.