道路交通拥堵与城市雾霾污染的关系研究

An investigation into the relationship between road traffic congestion and urban haze

道路拥堵与城市雾霾是机动车行驶带来的两个负溢出效应,大量文献揭示了城市机动车行驶对二者带来的影响,却鲜有文献关注道路拥堵程度与雾霾污染之间的内在联系。这其中的缘由在于,一则道路拥堵程度与雾霾污染之间互为因果,同时有共同的影响因素,由此带来的内生性难题难以有效解决;其次,采用统一标准来测度不同城市道路拥堵程度的数据难以获得。为此利用高德地图(Amap)根据机动车定位导航系统提供的城市拥堵延时的大数据,来捕获各省会城市每日道路交通的拥堵程度,同时运用各城市每日的燃油销售价格、国际市场原油价格以及上一周同一工作日道路的拥堵程度作为工具变量,通过两阶段最小二乘法(2SLS)估计道路拥堵程度对城市雾霾污染的影响。回归结果表明:①以城市燃油价格作为工具变量时,道路拥堵程度每增加1%,会导致省会城市PM2.5、PM10分别增加6.5%和6.7%;②以国际原油价格、上一周同一个工作日拥堵程度作为工具变量,以及改用GMM方法进行估计时,基准回归的结论仍然稳健,城市的治堵举措与治霾举措能够相互协同;③进一步以省会城市新增轨道交通来实现治堵和治霾的例子表明,发展轨道交通来实现治堵与治霾的协同效应,要以有效治堵作为前提,否则减排治霾的协同效果无法实现。

Both road traffic congestion and urban haze resulted from motor vehicle driving have negative spillover effects.Most literature looks for the causes of urban haze from road traffic,but little attention has been paid to the relationship between road traffic congestion and urban haze pollution due to the endogenous problems caused by their mutually causal relationships and common influencing factors as well as the lack of systemic data to measure the cases of traffic congestion among cities by using unified standards.Based on the big data of urban congestion delay index provided by the road-condition capturing function of Amap’s motor vehicle positioning and navigation system,this article aims to carry out an investigation into the relationship between road traffic congestion and urban haze by employing data of daily fuel price,international crude oil price and congestion index of the same working day of the previous week as instrumental variables,so as to make up for the deficiency of existing literature.The results show that:①there was a positive causal relationship between road traffic congestion and haze.For every 1%increase in road traffic congestion,the concentration of PM2.5 and PM10 increased by 6.5%and 6.7%respectively;②when using international crude oil price or congestion index of the same day of the previous week as an instrumental variable respectively and GMM method to estimate,the conclusion was still robust;③developing new rail transit in provincial capital cities to achieve the synergistic effect of congestion regulation and haze control still needs the effective mitigation of road congestion as a prerequisite.The enlightenment for the policy practice is that the primary task of urban regulation is to effectively solve urban road traffic congestion in order to achieve emission reduction and pollution control,and then reduce the degree of urban haze pollution.