Subway,transport Energy Consumption And Air Pollution

Since the reform and opening up,China’s economic development has achieved remarkable results.Meanwhile,China’s urbanization process has also made great progress.The increasing urban energy consumption caused by urbanization development is an important factor contributing to China’s high total energy consumption.Within the city,transportation is an important source of urban energy consumption and the proportion is increasing.The transportation industry consumes a lot of primary and secondary energy,as well as a lot of greenhouse gas emissions and smog.As an efficient public transportation system,the subway system was regard as an important way to solve urban traffic problems.The opening of the subway will undoubtedly relieve the traffic pressure and meet the commuting needs of urban residents.However,the impact of the opening of the metro on urban air quality remains to be tested.In view of the current literature,this paper finds that there is no consensus on whether subway can affect urban air quality in the academic circle.Most of the existing studies are limited to a certain city or a certain line.There is a lack of overall research on the city level and a lack of exploration on the mechanism of subway’s influence on urban air quality.From the perspective of negative externality of traffic and air pollution control,this paper explored the mechanism of subway affecting urban air quality and deduced the theoretical model.Meanwhile,in order to enrich the research in this field and provide a new perspective of subway influence mechanism of the urban air quality,this paper employed the panel data of China’s 78 large city in 2003-2018,and put the operation of subway service as a natural experiment,to identify the impact of subway on urban air quality based on DID method.Then,this paper further explored the mediation effect of the urban transportation energy consumption in the impact path.Finally,this paper also explored the traffic substitution effect of the subway to the urban road traffic through the vehicle ownership and annual mileage data.The empirical results of this paper indicated that the opening of subway service can significantly reduce the level of urban air pollution and improve urban air quality,and the opening of subway can reduce the urban air quality index AQI by about 0.7units.Mechanism research showed that the opening of urban subway can improve urban air quality by reducing urban per capita transportation energy consumption.The opening of subway shows a certain degree of traffic substitution effect,which promotes the change of urban residents’ travel mode,and its traffic creation effect is not obvious.However,due to the limitation of its scale and intensity,the traffic substitution effect of subway does not completely change the overall pattern of urban residents’ reliance on cars for travel.This paper provides theoretical and empirical evidence for further strengthening the role of subway in changing urban traffic pattern,reducing urban traffic energy consumption and improving urban air quality.