中文摘要：

采用北京大学城市大气边界层模式模拟了城区下风向绿化带对城市温度场、风场及空气质量的影响。模拟表明，一天中不同时刻绿化带附近存在不同程度的污染加重现象，上午10：00（北京时）污染浓度最大增加66％；绿化带降温范围最大达到下风向0．5km。同时还进行了下风向绿化带与城区加强绿化的对比数值试验，结果表明，城区加强绿化后绝大部分范围气温出现较明显下降，最大降温幅度为1．6℃。此项研究可为园林及城市规划等部门提供参考。

英文摘要：

The impact of greenbelt at the downwind periphery of an urban area on urban atmospheric environment and air quality was simulated by using the Peking University Urban Atmospheric Boundary Layer Model. Three cases with different distribution of greenery patches were tested. The results show that the temperature Change caused by greenbelt may induce secondary circulation and pollution redistribution. After construction of the greenbelt, the pollution increase with maximum value of 66% at 1000 BT （Beijing Standard Time） is found. The scope of temperature drop of the greenbelt can only extend to 0. 5 km downstream. If the trees in the greenbelt are evenly distributed on the urban area, the drop of temperature will appear over the whole urban area with the maximum of 1.6℃ at the downwind area. The research may be beneficial to a better understanding of the effects of greenbelt on the urban environment and well designing urban greenbelt patches.