典型城市街道内汽车排放污染物扩散规律的模拟研究

Numerical study on traffic pollutant dispersion in urban street canyons

采用自主开发的街道峡谷内污染物扩散模式,对城市中几种典型的街道峡谷内流场和污染物的浓度场进行了模拟研究。模拟结果表明:在一定气象条件下,街道中机动车排放污染物的扩散受街道宽高比、街道两侧建筑物对称性、街道两侧建筑物高度分布及街道两侧的建筑物形状等因素的影响;街道峡谷宽高比接近1时、递升型峡谷以及宽阔街道有利于污染物的扩散。

In present study, an urban street canyon dispersion model developed in our unit was used for the simulation of fluid fields and vehicle emissions＇ dispersion in the typical street canyons. The study shows that the dispersion characteristics of vehicle emission pollutants in street canyons, in a certain meteorological condition, depend on the width/height ratio of a street canyon and symmetry, and the building＇s shape of blocks surrounding the line source. Pollution concentrations in the street canyons with width/height ratio around 1, with step-up notch configuration and with wider street are relatively low.