轨道交通建设与空气质量改善

Urban Rail Transit Construction and Air Quality Improvement

兴建轨道交通被认为是当前一项能够以较低的社会福利损失为代价解决交通拥堵和空气污染问题的有效措施。然而,传统回归研究存在无法解决内生性所导致的估计偏误问题的限制。本文运用断点回归(RD)模型对全国2014年至2019年间新开通的84条轨道交通线路在24个城市的空气污染影响进行了研究。研究结果显示,轨道交通的开通有利于促进空气污染水平的下降。此外,本文还考察了轨道交通减排效应在不同城市异质性的表现,发现随着城市的人口规模、经济水平的提升,污染治理效应得到了增强。此外,研究还揭示了轨道交通与共享单车的治污效果存在规模效应,表明当前我国的城市轨道交通与共享单车的建设尚未达到饱和状态。最后,以武汉市为例,本文还对共享单车和轨道交通的协同减排机制进行了分析。研究发现,共享单车很好地满足了出行者在轨道交通系统中的“最后一公里”接驳需求,并且增强了轨道交通的减排效益,为共享单车的减排研究提供了一条新的研究路径。

The construction of mass transit is regarded as an effective measure to combat urban traffic congestion and air pollution,with relatively low social welfare costs.However,conventional regression studies fail to address the issue of endogeneity,resulting in estimation biases.This study utilizes the regression discontinuity(RD)model to investigate the impact of 84 newly opened mass transit lines in 24 cities across China from 2014 to 2019 on air pollution.The findings reveal significant and robust emission reductions in emissions associated with the introduction of mass transit.Furthermore,this study examines the urban heterogeneity of emission reductions caused by mass transit.It is found that the pollution control effects are more pronounced in cities experiencing population growth,economic development,and increased pollution levels.Additionally,the study uncovers a scale effect,suggesting that Chinese cities have not yet reached the saturation point in terms of the pollution mitigation benefits of mass transit.Lastly,taking Wuhan city as an example,the study analyzes the synergistic emission reduction mechanism between bike-sharing systems and mass transit.It is discovered that bike-sharing systems effectively address the last-mile connectivity needs of commuters,thereby enhancing the emission reduction benefits of mass transit.These findings provide valuable insights for further research on emission reduction through bike-sharing systems.