中文摘要：

机动车尾气是当前城市污染的主要元凶之一。通过摄像机抓拍和图像识别方法得到街道的车流量信息，结合国家环境保护部发布的车辆排放因子信息。计算得到街道的排放源强，接着运用湍流模型和多孔介质理论，结合计算机数值模拟的方法得到街道峡谷内的流场和污染物浓度分布，可以为城市道路设计和尾气污染治理提供科学合理的依据。

英文摘要：

Vehicle emission is the main culprit for the air pollution in the city. Through the camera capture and image recognition method, the information about vehicle volume is obtained. Combined with the information about vehicle emission factors that is published by the Ministry of Environmental Protection, the emission intensity of the streets is calculated. Then based on the model of turbulence and the theory of porous media, the flow field and pollutant concentration distribution in street canyon are obtained by computer numerical simulation. The data obtained can provide a scientific basis for the urban street design and exhaust pollution control measures.