Vehicle exhaust emissions are major sources of air pollution in urban areas. This study investigates the influence of roadside green belts, spatial urban street layout, and wind speed on the dispersion of vehicle exhaust emissions in street canyons using numerical simulations. Personal daily mean pollutant intake was calculated to assess the extent of exhaust exposure in street canyons. Results showed that pollutant levels decreased with tree spacing, with the optimal spacing being 0.4 times the building height. The recommended aspect ratio of street canyons was less than 0.67. Setting green belts in the center of roads and near the leeward side of buildings is beneficial for pollutant dispersion from street canyons. These results can be used to effectively improve the air quality in street microenvironments, provide pollution protection for low-rise dwellers and pedestrians, and provide a basis for reconstructing and modifying old street buildings.

汽车尾气排放是城市地区空气污染的主要来源。本研究通过数值模拟研究了路边绿化带、空间城市街道布局和风速对街道峡谷中车辆尾气排放扩散的影响。计算个人每日平均污染物摄入量以评估街道峡谷中废气的暴露程度。结果表明，污染物水平随着树距的增加而降低，最佳树距为建筑高度的0.4倍。推荐的街道峡谷纵横比小于 0.67。在道路中心和建筑物背风侧附近设置绿化带，有利于街道峡谷的污染物分散。这些结果可用于有效改善街道微环境中的空气质量，