城市街区形态布局对大气颗粒物扩散及人群暴露空间变化的影响机理研究

The pollution of atmospheric particulate matter is more and more serious in cities and city agglomerations with the acceleration of urbanization and industrialization process and rapid increase in vehicle ownership in China. The research on the mechanism of regulation of atmospheric particulate matter dispersion and assessment of population exposure to particulate matter pollutants at the neighborhood scale is of great practical significance to guide urban planning and architectural design scientifically, improve air quality, and achieve sustainable development of human settlement. Selecting Shanghai city as the study area, this project will be carried out from the perspective of optimization of neighborhood spatial structure and layout. The methods and techniques of in-situ observation, field validation, data mining, numerical simulation, and planning and regulation will be applied to developing the linear and non-linear models of the relationship between urban morphology at neighborhood scale and the distribution of particulate matter concentration, studying the regulation of transport and dispersion of particulate matter in a variety of scenarios through CFD (Computational Fluid Dynamics) simulation and wind tunnel experiment, deriving quantitative spatio-temporal information of typical population exposure to particulate matter by innovating the method of assessing population exposure to pollutants, exploring the mechanism of impact of neighborhood morphology and fabric and architectural complex layout on micro-meteorology change, atmospheric particulate matter dispersion and spatio-temporal variation of different group of population exposure to particulate matter, and proposing the comprehensive optimization design scheme for improving atmospheric environment at neighborhood scale. From the theory to practice, this project aims to provide direct and operable scientific basis for optimization of spatial planning and design at neighborhood scale and formulation of air pollution prevention and control measures for the cities in China.

随着我国城市化和工业化进程的加快、机动车保有量的迅速增加，城市和城市群区域大气颗粒物污染状况不断加剧。开展城市街区尺度大气颗粒物扩散规律的机理研究和人群污染暴露评价，对于科学指导城市规划和建筑设计、改善空气质量、实现人居环境的可持续发展具有重要的现实意义。本课题将以上海为区域背景，从城市街区空间结构布局优化的角度出发，采用实测、验证、数据挖掘、数值模拟、规划调控的技术方法，构建街区形态结构与大气颗粒物浓度分布的线性和非线性模型；结合CFD模拟技术与风洞实验研究多种情景下颗粒物传输和扩散规律；创新空气污染暴露评价方法，获取典型人群污染暴露时空量化信息；研究街区空间形态、建筑群结构布局对微气候变化、颗粒物扩散以及不同人群污染暴露时空变化的影响机制，提出城市街区大气环境综合优化设计方案。从理论和实践层面，力求为优化街区空间规划设计、制定我国城市空气污染防治措施提供直接并具操作性的科学依据。

街区作为城市空间的基本单元，是居民活动中最为活跃的场所，也是空气污染物最易积聚的热点区域。开展城市街区尺度大气颗粒物扩散规律的机理研究和人群污染暴露评价，对于科学指导城市规划和建筑设计、改善空气质量、实现人居环境的可持续发展具有重要的现实意义。本课题从城市街区空间形态度量和空气流通状况评估入手，构建了一套能全面量化街区形态结构的指标体系；以上海为区域背景，采用实测、验证、数据挖掘、数理统计和数值模拟等技术方法，提取出与大气颗粒物扩散分布关系最为密切的空间形态测度指标集，包括路网密度、迎风面积指数、空间拥挤率、综合孔隙度、形状指数、水域面积比例、不透水面盖度和峡谷平均高宽比，涵盖了土地开发利用强度、街谷空间形态、建筑结构布局、下垫面粗糙度、生态景观分布、三维建筑景观评价指标和通风评价指数7个方面；建立了街区形态结构与大气颗粒物浓度分布的关系模型，揭示了多因素之间的耦合关联对于大气颗粒物浓度变化的综合影响机理；运用计算流体动力学（CFD）模拟技术构建了多种情景下（不同的建筑群规划设计方案）微环境中大气颗粒物扩散分布的三维数值模拟模型，揭示了街区空间形态、建筑群结构布局对于微环境中大气湍流运动、对流效应以及颗粒物传输、扩散的影响机制；识别出在街区微环境中具有较高颗粒物暴露风险的人群及其活动空间，揭示了城市典型人群污染暴露变化特征及其与街区建筑群形态结构之间的关系；根据上述对不同情景下微环境中气流场、PM2.5浓度场以及人群污染暴露指数的三维数值模拟结果，通过比较不同的建筑群规划设计方案对于促进大气颗粒物扩散和稀释以及降低颗粒物污染暴露水平的有效作用，以改善城市空气质量为目的，提出了城市街区大气环境综合优化设计方案。基于以上研究成果，本课题从理论和实践层面，为优化城市街区空间结构布局与规划设计、制定我国城市空气污染防治措施提供了直接并具操作性的科学依据。