Purpose of Review

The air quality management within urban street canyons can be improved by enhancing ventilation for dispersion of pollutants. The purpose of this review is to summarize effects of various impact factors on airflow and pollutant dispersion in urban street canyons. The relative intensity of different influence factors is reviewed, which should provide a useful comprehensive guide for modelling of these effects for urban developments.

Recent Findings

All reviewed numerical simulations, wind tunnel and outdoor scaled model experiments show that the various building heights and incoming airflow conditions could produce a clear influence on airflow and pollutant dispersion in urban street canyon. Outdoor scaled experiments have provided complex turbulent data and illustrated the complexity of airflow within urban street canyons, which would require comprehensive simulations to investigate the microclimate within these urban street canyons.

Summary

Impacts of thermal and/or wall heating conditions have been fully studied, while the impact of inflow variation, building height difference, model scale and the coupling effect of different factors are current hot topics for research. Building height difference and time-varying inflow conditions are factors of most significant influence, while tree planting, vehicle-induced turbulence, thermal and/or wall heat conditions have a relatively weak influence.

中文翻译：

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城市街道峡谷中气流和污染物扩散的影响因素及综合模拟：综述

审查目的

通过加强通风以分散污染物，可以改善城市街道峡谷内的空气质量管理。本文的目的是总结各种影响因素对城市街道峡谷中气流和污染物扩散的影响。审查了不同影响因素的相对强度，这应为建模这些影响城市发展提供有用的综合指导。

最近的发现

所有回顾的数值模拟，风洞和室外比例模型实验均表明，不同的建筑物高度和传入的气流条件可能会对城市街道峡谷的气流和污染物扩散产生明显的影响。户外规模的实验提供了复杂的湍流数据，并说明了城市街道峡谷内气流的复杂性，这将需要全面的模拟来研究这些城市街道峡谷内的微气候。

概要

已经充分研究了热和/或壁加热条件的影响，而流入量变化，建筑物高度差，模型规模和不同因素的耦合效应的影响是当前研究的热点。建筑物高度差和随时间变化的流入条件是影响最大的因素，而植树，车辆引起的湍流，热和/或壁热条件的影响相对较弱。