Impact Of Vehicle Restriction Policy On Air Quality And Public Health In Beijing

With the rapid economic growth in last decades, the vehicle ownership has increased significantly in Beijing. Although the increase of motorization rate brings great convenience to daily life, its negative effect on transportation management and air quality is also significant, and the vehicular emissions has become the major source of the primary air pollutants in Beijing, making it a direct threat to public health. In order to ease traffic congestion and improve air quality, vehicle restriction policy was first conducted during the 2008 Beijing Olympic Games, which has been a regulatory policy for controlling traffic congestion and air pollution in Beijing.And previous studies largely focus on the topics of traffic and air quality which are related research directions of vehicle restriction policy, but the consequences of the policy on public health in Beijing have so far been neglected in prior studies. Therefore, it is full of theoretical and practical value to investigate the effect of vehicle restriction policy on air quality and public health in Beijing.Based on previous studies and also current situation in Beijing, impact factors about air quality and public health are summarized, and variables are chosen as follows: air quality index, respiratory outpatient visits, emergency numbers, meteorological factors(average temperature, relative humidity, average wind speed) and workday variables. We estimate a non-linear model called generalized additive model as our basic model according to epidemiological studies. Moreover, taking into account of the distinct seasonal characteristics in Beijing, we introduce an interaction term of restriction and season to estimate the effects of restriction policy in heating season and non-heating season respectively. In addition, we also examines the effects of different lag structures and lag periods on the basic model and the interaction model. Then, we run the models in R and draw the research conclusions. We make policy suggestions based on the research conlusions, and hope it could be an important reference to the vehicle restriction policy and contribute to the improvement of air quality and public health in Beijing.