街谷细颗粒物分布特征及其与设计指标关联性研究

Study on distribution characteristics of fine particulate matter in street canyon and its correlation with design indexes

针对城市街道峡谷空间不利于交通污染扩散问题,该文采用移动与固定相结合的实际监测及数值模拟技术,分析了城市街谷PM_(2.5)时空分布特征及其与街谷空间形态设计指标的关联性,并提出空间形态优化策略。结果表明:①街谷内PM_(2.5)质量浓度在日际变化上呈现连续递减、日内变化上呈现先下降后上升的趋势,而在空间分布上呈现主干道及高层建筑附近浓度较高的趋势;②建筑高度比与街谷高宽比的增加使得PM_(2.5)质量浓度呈现下降趋势,街谷长宽比的增加使得PM_(2.5)质量浓度呈现上升趋势;③建筑高度降低对街谷内PM_(2.5)质量浓度影响最大,其次是建筑底层架空及建筑退让。该文研究结果可为健康城市导向下的城市街道峡谷空间形态优化设计提供参考。

Aiming at the problem that the space of urban street canyons is not conducive to the diffusion of traffic pollution,this paper analyzed the spatial and temporal distribution characteristics of PM_(2.5)in urban street canyons and its correlation with the spatial pattern design index of street canyons by using the practical monitoring and numerical simulation techniques combining mobile and fixed,and proposed the spatial pattern optimization strategy.The results showed that:①The PM_(2.5) mass concentration in the street valley showed a continuous decrease in the daily variation,and showed a trend of first decreasing and then increasing in the diurnal variation,while in the spatial distribution,the concentration showed a higher trend near the main road and high-rise buildings.②The increase of building height ratio and height-width ratio of street canyon leads to a downward trend in PM_(2.5) mass concentration,while the increase of length-width ratio of street canyon leads to an upward trend in PM_(2.5) mass concentration;③The decrease of building height has the greatest impact on PM_(2.5) mass concentration in the street canyon,followed by the building floor overhead and building concessions.The results of this study can provide an important reference for the optimal design of the spatial form of urban streets and canyons under the guidance of healthy cities.