Abstract
Air pollution is a global problem and the transportation industry is one of its major causes, yet the impact of transportation infrastructure on air quality is little understood. It is vital to know about evaluating the effects of transportation infrastructure on air quality. The urban road has a role in defining air pollution and automobiles significantly contribute to the air quality in urban areas. The issues are a result of the automobile's impact on air quality. China put substantial investments in its metropolitan subway networks. The information on air quality on an hourly basis, daily metrological data, and demographic profiles of various cities with significant subways from the year 2013 to the year 2014 used. This study examines the effect of substantial investment on urban air quality. The Discontinuity Based Ordinary Least Squares (DB-OLS) on data for further analysis with results are incorporated in the study. The researchers witnessed a 14% reduction in air pollution during the daytime in those not rushed cities. Researchers discovered that the impacts are less severe in urban areas with a lower population density and a higher income. The results will be less dangerous if more subways affect the air quality.