The Impact Of Urban Sprawl On Air Pollution

In the process of China’s rapid urbanization,there is an obvious phenomenon that "land urbanization" is too fast,and the excessive growth of urban space leads to the urban sprawl,which leads to the problem of environmental pollution.Environmental problems are also the problems that must be solved to achieve high-quality development in China.Therefore,based on the existing research,this paper deeply analyzes the internal mechanism of the impact of urban sprawl on air pollution,and uses the panel data of 228 cities in China from 2003 to 2016 as samples to explore the impact of urban sprawl on air pollution,and tests the mediating effect of car ownership in the impact of urban sprawl on air pollution.The results show that:(1)there is a significant "inverted U" relationship between urban sprawl and air pollution,but most cities in China are on the left side of the "inverted U",that is,urban sprawl will aggravate air pollution,and a few cities can cross the inflection point and play a role of mitigation.(2)There is also a significant "inverted U" relationship between urban sprawl and car ownership.There is a significant positive relationship between car ownership and air pollution.Car ownership plays a partial mediating role in the process of urban sprawl affecting air pollution.In addition,after stripping the mediating effect of car ownership,the direct impact of urban sprawl on air pollution presents a "U" relationship The direct effect is weaker than the intermediary effect.(3)The impact of urban sprawl on air pollution will be affected by regional or urban differences.In large and medium-sized cities,the impact of urban sprawl on air pollution is stronger.Compared with the eastern,central and western regions,urban sprawl has a positive impact on air pollution in the eastern and central regions,and the eastern region is greater than the central region,while in the western region,urban sprawl has a negative impact on air pollution.(4)By quantile regression,the higher the air pollution level,the stronger the direct effect of urban sprawl,and the weaker the intermediary effect of car ownership.Finally,according to the research conclusions,the paper puts forward some countermeasures and suggestions on how to alleviate urban sprawl and reduce air pollution.