Research On The Impact Of Traffic Density On Air Pollution

Since the 30 years of reform and opening up,China’s economy and urbanization continues to increase.However,with the development of economy and the acceleration of urbanization,the problem of "urban disease",which is consist mainly of air pollution and traffic congestion,is getting worse.Under such circumstances,Communist Party of China first proposed that Ecological civilization construction must be placed in a prominent position in The Eighteenth National Congress of the CPC.Compared with the past,the contradiction between the economic development and environmental pollution is getting more acute.So how urban traffic congestion affect the air pollution and to what extent urban traffic congestion has exacerbated air pollution?This has become a problem worthy of study.Firstly,according to the principle of externality of traffic congestion,this paper discusses the theoretical mechanism of air pollution affected by traffic density,and then based on the output density model(Ciccone&Hall,1996),infer the theoretical model of traffic density affecting air pollution,and next based on EKC model and IPAT model,we use the panel data of 111 key environmental protection cities in China between 2003-2012 to study how traffic density affecting air pollution,and use the instrumental variables and GMM methods to test the endogeneity between traffic density and air pollution,further use the quantile estimation method and treat other air pollutants as explained variable to test the robustness of the model.Finally,by introducing the interaction between traffic density and per capita GDP,per capita GDP’ square item and per capita GDP’ cubic item,we test the mechanism of traffic density affecting the air pollution.The empirical results show that:(1)China’s urban traffic density has a positive effect on air pollution.The per capita GDP and foreign direct investment has a negative effect on air pollution,while the secondary industry and the tertiary industry to some extent exacerbated the air pollution in the city.(2)There is a significant linear relationship between traffic density and air pollution both in large cities and small cities.However,compared with the large city,traffic density has stronger positive influence on air pollution in small city;Traffic density and air pollution show linear relationship in the eastern cities,however,they show "U" type relationship in the Midwest city.(3)Treating the lag term of traffic density as the traffic density’s instrumental variables,we examined the endogeneity between traffic density and air pollution.The results show that there is no endogeneity between traffic density and air pollution.And the results of the systematic GMM further support the above conclusions.(4)Using the quantile estimation method and treating the other air pollutants as the explained variables to further test the robustness of the model setting,the results show that model setting of traffic density affecting the air pollution is robust.(5)By introducing the interaction between traffic density and per capita GDP,per capita GDP’ square item and per capita GDP’ cubic item,we find that traffic density can affect air pollution by affecting the total social production costs...