Urban street canyon is one of the most important characteristics and spatial forms of cities. It is one of the most frequently used public spaces in cities, with the most serious automobile exhaust pollution and the largest population density. The unreasonable space configuration and internal composition might decrease self-purification of urban ventilation but increase local air pollutant concentration. Here, we reviewed the impacts of street canyon morphology, street trees, vehicle flow and meteorological factors on the distribution of air pollutants in street canyons. We scrutinized the relevant methods of numerical simulation, wind tunnel experiments, and field monitoring on the distribution and diffusion of air pollutants in street canyons. We recommended that future research should concentrate on the impacts of various parameters on the distribution and diffusion of air pollutants based on the field monitoring data. Meanwhile, further research should develop optimization strategies for street canyon design which is conducive to the dispersion of air pollutants, and put forward scientific support and optimization scheme for the controlling of air pollutants from the perspective of urban planning and pattern optimization.
城市街谷是现代城市最重要的空间形式与特征之一,是城市中使用频率最高、汽车尾气污染最严重、日常人口密度最大的公共空间类型之一。城市街谷不合理的空间配置和结构会造成城市通风自净能力降低,大气污染物浓度增高。本文综述了城市街谷形态、行道树配置、机动车车流量和气象因素等对街谷大气污染物分布的影响,以及数值模拟、风洞试验和实地监测等用于街谷大气污染物分布及扩散研究的相关方法。建议未来以实地监测数据为基础,综合考虑多种因素对街谷大气污染物分布的研究,提出适宜城市大气污染物扩散的城市街谷构建模式,从城市规划和格局优化的角度为城市大气污染物的减控提出科学支撑和优化方案。.
Keywords: 3-dimension pattern; air pollutant; dispersion; street canyon; street tree.