Impact of gasoline upgrade policy on particulate matter pollution in China

Automobile exhaust pollution is one of the major contributors to the severe air pollution in China, and policies have been issued by the Chinese government to mitigate this problem. In this paper, we evaluate the impact of a recently implemented policy to upgrade the quality of gasoline on reducing the fine particulate matter (PM) concentration. Based on regression discontinuity (RD) design, we systematically analyze the policy effect on the PM10 and PM2.5 concentrations at three scales, namely, the macro-, meso-, and microscales. Macroscale analysis measures the impact on all cities, and mesoscale analysis measures it on all monitoring stations, while microscale analysis focuses on the rush hours at each station. Our results show that the policy has little effect on reducing particulate matter pollution at the macro- or mesoscale, while positive evidence does exist at the microscale when focusing on pollution reduction during rush hours, especially for areas near main roads or junctions with heavy traffic. Our research suggests that the policy impact is affected by the heterogeneous pollution sources, and the potential of mitigating air pollution by continually upgrading the quality of gasoline will be limited after five stages of upgrades. In addition, one single policy can hardly completely solve particulate matter pollution in China, and a systematic design consisting of a series of policies is needed to mitigate this problem.