“健康中国”成为国家战略，健康问题成为全社会关注的热点话题。已有研究强调通过对建成环境的干预增加居民户外体力活动进而提高其健康水平，但因此造成居民长期暴露于有害气体中，可能会对健康产生更大的负面效果。特别在中国空气污染严重，体力活动带来的健康获益能否抵得过体力活动时空气污染物暴露而带来的健康损失？建成环境对健康的影响存在多重路径，相互之间有交互胁迫作用。因此，需要综合评估建成环境对健康的影响机制及效应。本项目利用GPS与活动日志相结合的居民出行-活动数据、城市土地利用和空气污染物监测数据，以活动分析法、“污染物时空暴露模型”、“建成环境随机时空暴露模型”为基础，分析建成环境通过体力活动和空气污染暴露对健康影响的模式及机制，对比、评估和模拟不同建成环境对健康影响的综合效应。并根据研究结果，从土地利用、交通设施供给、交通管理等方面提出政策建议，为城市政府制定相关政策提供决策理论依据与实际指导。

“Healthy China” has become a national strategy and health-related problems have gained more and more attentions from academics and policy-makers in recent years. Previous studies have demonstrated that physical activity could exerts various positive influences on health. Despite the virtues of physical activity-friendly environments, they could also pose risks. In particular, increased physical activity outdoors in an urban environment may have detrimental health consequences due to exposures to prevailing air pollution, especially in the countries with heavy air pollution such as China. Do the health benefits of physical activity outweigh the risks? It seems that built environment has multiple impacts on health and those impacts might have tradeoffs with each other. It is timely to systemically assess the impacts of built environment from the many pathways. Based on the data of activity and travel survey based on GPS and air pollution, this project will deploy models of behavior analysis, Space-time Exposure System and Built Environment Stochastic Spatial-Temporal Exposure Model to reveal how and to what extent the built environment influence physical activity and consequently impacts on health. In the meanwhile, the detrimental impacts of air pollution exposures on health because of physical activity will also be examined. The project will compare and simulate the health benefits of physical activity and risks due to exposures to air pollution. The project will end with a proposal of an Intergraded Land Use-Transport Policy Package including policies regarding land use, transport facility provision, transport management and investment which aim to promote the net health benefits of built environment in urban China.