城市轨道交通扩张与空气质量：聚焦网络效应

城市轨道交通往往被认为可以通过替代道路交通而改善空气质量，然而实证研究对此并无定论。以深圳为例，作者采用双重差分法研究了深圳城市轨道交通发展对空气质量的动态影响。研究结果表明，城市轨道交通扩张与空气污染之间的关系随时间变化，且取决于网络密度和规模。2010年地铁线扩建之前，深圳城市轨道交通网络密度仍较低，空间服务覆盖有限，因此新站点的开放对当地空气质量没有显著影响，甚至使空气质量恶化。然而，随着城市轨道交通网络更加密集，2016年的扩张显著降低了空气污染。此外，轨道交通对空气质量的影响会从新开放的站点溢出到现有站点。最后，城市轨道交通发展对符合公共交通导向型特征的社区会产生更大的空气净化效果。

Metro-line expansions and local air quality in Shenzhen: Focusing on network effects

We examine the air-quality effects of urban-rail development in Shenzhen, taking a difference-in-differences approach. This study is motivated by existing mixed evidence on the rail-pollution relationship, which we associate with the dynamic nature of the relationship itself. Our results demonstrate that the relationship varies by time, depending on network density and scale. New station openings had no significant impacts on local air quality or even worsened it until the 2010 metro-line extension, when Shenzhen’s metro network density was still low, with limited spatial service coverage. However, the 2016 extension significantly abated air pollution as the network grew denser and more comprehensive. The rail-driven anti-pollution effects tended to be further strengthened with externalities arising from improved network connectivity, spilling over the effects beyond newly opened stations to preexisting ones. Also, metro stations in proximity to neighborhoods that share key characteristics in transit-oriented development tended to generate a greater anti-pollution effect.

讲座人介绍：

欧逸夫，2022年博士毕业于香港大学(The University of Hong Kong)城市规划及设计系，现为香港理工大学(The Hong Kong Polytechnic University)土地测量及地理资讯学系博士后研究员。主要研究领域包括城市可持续发展，环境经济，土地利用与交通规划，并在Transportation Research Part D: Transport and Environment, Land Use Policy, Travel Behaviour and Society, Environment and Planning B: Urban Analytics and City Science, Environmental and Resource Economics等期刊发表高质量论文10余篇。