Can urban rail transit systems alleviate air pollution? Empirical evidence from Beijing

Abstract

Improving air quality across mainland China is an urgent policy challenge, while rapidly increasing use of vehicles poses a great menace to the urban population and air quality. Public transportation has received increasing attention as emissions- friendly transport options, but whether the urban rail transit system has a significant effect on curbing air pollution has been unclear, and there is a lack of explicit case studies in mainland China. Therefore, the effects of the opening of the Beijing Metro on air pollutants emissions in Beijing were quantified through a regression discontinuity design. Beijing has seen a brisk growth in its rail transit infrastructure and a downward trend of air pollution index since 2005. The regression results show that the operation of the rail transit system was observed to have a significant effect on reducing most of the air pollutants concentrations (PM2.5, PM10, SO2, NO2, and CO) but had little effect on ozone pollution. The results obtained were highly robust across a variety of tests. This study contributes to empirical evidence on the air pollutants associated with the opening of rail transit and traffic-related pollution control policy making in Beijing.