限行政策是否改善了北京市的空气质量?

Did Driving Restrictions Improve Air Quality in Beijing?

本文考察了北京在2008年奥运会之后采取的限行政策对空气污染指数(API)、可吸入颗粒物(PM10)、二氧化氮(NO2)和二氧化硫(SO2)等空气质量指标的影响,虽然传统的OLS回归显示限行政策有很强的效果,当采用断点回归的方法解决其内生性问题后,限行政策尤其是"尾号限行"对空气质量的影响甚微。基于限行导致购车行为改变假设的成本—收益分析,初步估计限行给驾车出行者带来的年成本约为北京市人均GDP的3%,年总成本约为当年GDP总量的0.3%。

This paper analyzed the impacts of Beijing＇s driving restriction policies during and after 2008 Olympics on a series of air quality indicators： API, PM10, NO2 and SO2 concentrations. Although OLS regression shows such policies are effective, after applying ＂Regression Discontinuity＂ （RD） method to solve endogeneity problems, we found driving restriction policies, especially the ＂one-day per week＂ restriction policy, had little impact on air pollution concentrations. Considering driving restriction might induce drivers to pur- chase a second car, we conducted a cost-benefit analysis and estimated the welfare cost is about 3% of per-capita GDP, or aggregated for 0.3~//00 of total Beijing GDP.