推行共享单车和轨道交通是否改善了空气质量:以武汉为例

Can Popularity of Rail Transit and Bike-sharing Improve Air Quality?——A Case Study on Wuhan City

以武汉推行共享单车和轨道交通为例,采用空气质量指数(AQI)和监测空气质量的六种污染物CO、NO2、PM10、PM2.5、O3、SO2日度和小时浓度数据,运用断点回归检验这两种理论上能提供居民短距离和远距离绿色出行的方式,是否在实践中改善了空气质量。研究发现:(1)推行共享单车和轨道交通显著降低了AQI、CO、PM10、PM2.5,而且在考虑空气质量对出行方式的内生影响后,仍表现出对AQI的显著改善效应。分时间段进行异质性检验(轨道交通运行期、出行高峰期)和反事实分析(轨道交通非运行期),其结论保持不变。(2)相比于市政型共享单车,除对O3外,市场型共享单车对其他污染指标都存在更强的抑制作用。(3)推行共享单车有助于轨道交通对除PM10和O3外其他污染指标的改善,而市场型共享单车还能显著提升轨道交通对PM10的减排效果。综上所述,推行共享单车和轨道交通能对空气质量起到一定的改善作用,需要加强对自行车公共设施与轨道交通的建设,规范引导市场型共享单车的使用。

Rail transit and bike-sharing have become long-distance and short-distance green travel ways for residents. This paper takes the rail transit and bike-sharing in Wuhan city as an example and employs discontinuity regression （RD） to examine whether the usage of rail transit and bike-sharing improves the air quality in practice based on the daily data and hourly data of air quality index （AQI）, carbon monox- ide （CO）, nitrogen dioxide （NO2）, particulate matter 10 （PM^0）, particulate matter 2.5 （PMas）, o- zone （O：~）, sulfur dioxide （SO~）. The result shows that： firstly, the popularity of bike-sharing and rail transit decreases AQI, CO, P Mas, PM^0 significantly and it still decreases AQI with the consideration that air quality may affect travel ways endogenously. Additionally, the paper conducts a heterogeneity test （selecting the operational period of rail transit and the rush hours） and a counterfactual analysis （se- lecting non-operational period of rail transit） during different periods, and the results remain the same. Secondly, compared with municipal shared bikes, market-oriented shared bikes can reduce more pollu- tion indicators except O3. Thirdly, the popularity of bike-sharing can improve the negative effect of rail transit on pollution indicators except PM10 and O3. Furthermore, market-oriented shared bikes can help rail transit significantly diminish PM10. To sum up, the paper draws a conclusion that the popularity of rail transit and bike-sharing is beneficial to air quality; the construction of rail transit and public facilities for bicycles and the regulation for the usage of market-oriented shared bikes are required so as to deal with automobiles tailpipe pollution.