大量研究结果表明，街道两边的人行道旁密植行道树可以有效吸附街道颗粒物，改善微环境小气候，具有显著的滞尘减污作用。然而另一些研究显示街道峡谷内因行道树树冠覆盖影响而导致大气颗粒物扩散受阻，从而引发街道峡谷内的污染物聚集。针对以往研究出现的矛盾，本研究拟通过不同行道树绿容率（盖度、疏透度、叶密度）与街道峡谷特征下大气颗粒污染物浓度日变化和季节变化的实测，结合ENVI-met模型模拟，探讨街道峡谷内大气颗粒物的空间扩散规律对行道树覆盖的响应与调控机制，构建不同峡谷型街道中有利于颗粒污染物扩散的行道树绿容率指标，为不同街道的行道树配置及颗粒污染物扩散调控提供依据。

A multitude of studies have shown that trees can effectively absorb street particles and improve the micro-environment microclimate, with significant dust detaining and decontamination effects. However, other studies demonstrate that the dispersion of airborne particles in street canyon is blocked by the cover of tree canopy, which induces the accumulation of pollutants in the street. Aiming at the contradictions of the previous studies, the daily and seasonal variations of atmospheric airborne pollutant concentrations under different green densities (cover degree, porosity, leaf density) and street canyon characteristics were studied, associate with the ENVI-met model Simulation, to explore the spatial distribution of atmospheric particles in street canyon under different road tree coverage. This study discusses the response and regulation mechanism of the spatial distribution of atmospheric particulates on account of the coverage of trees in street canyons and establishes the green capacity index of road trees that are conducive to the dispersion of particulate pollutants in different canyon-type streets. It also provides evidences for the road tree configuration based on particle dispersion control.