Spatial effects of urban expansion on air pollution and eco-efficiency: Evidence from multisource remote sensing and statistical data in China

Existing literature mainly focuses on the impact of urban expansion on air pollution, while eco-efficiency comprehensively considers the high-quality development of the economy and the environment, and can more comprehensively measure the green development of cities. This study uses multisource remote sensing and statistical data from 268 cities in China from 2008 to 2018, combined with ArcGIS analysis, super-efficiency EBM-DEA (Epsilon Based Measure-Data Envelopment Analysis), and SDM (spatial Durbin model) to explore the spatial effects of urban expansion on air pollution and eco-efficiency. The results show that the Beijing-Tianjin-Hebei and Chengdu-Chongqing urban agglomerations are the areas with the most serious air pollution, while the high-value areas of eco-efficiency are mainly concentrated in the eastern coastal areas, and the low-value areas are located in the central and western regions. During the study period, the center of gravity of air pollution and eco-efficiency shifted to the northeast. In addition, urban expansion has a significant U-shaped relationship with air pollution, and a significant inverted U-shaped relationship with eco-efficiency. Appropriate urban expansion has strong positive externalities on the direct and spillover effects of air pollution and eco-efficiency. However, excessive urban expansion has aggravated the air pollution of local cities, but it is beneficial to the air improvement of neighboring cities. Furthermore, for every 1% increase in UEI2 in provincial capital cities, air pollution decreases by 0.1705%, and eco-efficiency increases by 0.0244%. However, the western region and small and medium-sized cities should strictly control spatial expansion and achieve “smart growth".