Research On The Impact Of Urban Rail Transit Opening On Air Quality In China

With the continuous progress of China’s social development,the coordination between urban development and ecological environment has become a focus issue.Among them,the problem of urban air pollution in China is becoming increasingly serious,which not only has a great impact on people’s production and life,but also poses a great threat to human survival and development.Traffic emissions caused by urbanization process is one of the main sources of air pollution.Reducing traffic emissions has become the key to solve the problem of atmospheric environment.As a high-capacity,fast,safe and environmentally friendly transportation mode,urban rail transit has become the primary development option for major cities in China to alleviate traffic congestion and improve travel efficiency.However,it is not clear whether urban rail transit can promote the improvement of air quality.From the perspective of transportation substitution theory,the opening of urban rail transit will improve the share of public transport in residents’ travel,reduce residents’ dependence on private cars,and thus reduce traffic pollutant emissions.But at the same time,the traffic creation theory believes that the development of urban rail transit will also attract more population and industrial agglomeration,expand the scope of urban economic activities,improve the average travel distance and frequency of urban residents,and then produce more traffic pollutant emissions.Therefore,studying the mechanism of the impact of urban rail transit on air quality can improve the environmental governance benefits of urban rail transit,and then realize the sustainable development between urban rail transit and the atmospheric environment,which is of great significance for the harmonious coexistence of human and nature.Based on this,this study comprehensively uses literature analysis method,interaction stress model,breakpoint regression model,entropy weight TOPSIS method,regression discontinuity design and other research methods,and combines externality theory,environmental carrying capacity theory,traffic substitution theory and traffic creation theory to carry out the substantive research on the impact of urban rail transit on air quality.Firstly,the influence mechanism of urban rail transit on air quality is explained,and on this basis,the interactive stress theory is introduced to establish the interactive stress model between urban rail transit and atmospheric environment,and the interaction relationship between urban rail transit and air quality is verified from a macroscopic perspective.Secondly,based on the regression discontinuity design,94 newly opened rail transit lines in 29 cities in China between January 2014～July 2020 were used to identify the impact of the opening of specific rail transit lines on air quality from a microscopic perspective,and a series of robustness tests were carried out to ensure the stability of the regression results.Finally,this study also analyzes urban heterogeneity from three dimensions: urban rail transit scale,economic development level and vehicle ownership,and further discusses the conditions for the traffic substitution effect and traffic creation effect of urban rail transit,as well as the specific mechanism of urban rail transit on air quality.The results show that there is an interactive stress relationship between urban rail transit and atmospheric environment,which shows that urban rail transit as a whole has a negative stress on the atmospheric environment and promotes the improvement of air quality,the atmospheric environment has a negative constraint on rail transit and accelerates the development of rail transit.However,from the perspective of each city,the development of rail transit has different traffic effects on cities,in cities with medium rail transit scale and economic development level,the traffic substitution effect of rail transit dominates,rail transit has a significant emission reduction effect on air quality,and in cities with high rail transit scale and economic development level,the traffic creation effect of rail transit dominates,and rail transit has a significant deterioration effect on air quality.According to the research results,this study proposes that the environmental governance benefits of urban rail transit should be improved from four aspects: rational planning of urban transportation layout,reducing dependence on fuel vehicle,optimizing the transfer efficiency of urban rail transit and public transport,and appropriately controlling the scale of urban expansion,so as to achieve sustainable development between urban rail transit and atmospheric environment.