CFD Modelling of the Deposition Effects of Trees on Traffic-Induced PM2.5 in an Idealized Street Canyon

摘要

This paper deals with deposition effect of avenue-like tree planting on traffic induced PM2.5 dispersion in urban street canyons by means of 3D numerical simulations validated by wind tunnel experiments.Deposition model is used to modify the concentration distribution inside an idealized street canyon with building aspect ratio W/H=2,traffic in the middle and two rows of trees aside.In the presence of deposition,the area-averaged particle concentrations decrease 13％ and 29％at the leeward wall and the windward wall,respectively,for particle diameter of 2.5 μm in respect of case without deposition.This study shows that deposition effect should be considered in predicting pollutant level within street canyons.The results obtained can be used by city planners for the design of tree planting in the urban environment with regard to air quality issues.