The effect of polycentric urban spatial structure on PM2.5: An empirical study of China

Environmental pollution causes widespread concern due to rapid urbanization and the ongoing expansion of the urban scale. Although the polycentric spatial structure is an important idea for regional environmental governance, the actual impact of optimizing the spatial structure differs significantly depending on socioeconomic variations. Existing studies lack an analysis of the effect of spatial structure on PM2.5 pollution. In this study, population centers from 2001 to 2018 in 369 Chinese cities were chosen to calculate the polycentricity. Then, the two-way fixed effects model and the threshold model were constructed to investigate the effect of spatial structure on PM2.5. The results indicate that cities in China have a tendency for polycentric spatial structure, with the most prominent in the east. According to the panel model results of polycentricity and PM2.5 concentration, polycentricity significantly increases PM2.5 pollution. Moreover, there is a significant single threshold effect for the population with a threshold value of 1.75 million. When the population exceeds 1.75 million, the effect of polycentricity on PM2.5 pollution becomes weaker. These findings can help provide valuable empirical analysis from the urban planning standpoint for preventing and managing PM2.5 pollution.

Automated summary

Environmental pollution is a major concern in China due to rapid urbanization and expansion of urban areas. This study examines the impact of spatial structure on PM2.5 pollution by analyzing population centers in 369 Chinese cities from 2001 to 2018. The results show that the polycentric spatial structure significantly increases PM2.5 pollution, especially in the eastern region. However, there is a threshold effect, where the impact of polycentricity becomes weaker when the population exceeds 1.75 million. These findings provide valuable empirical analysis for urban planning to prevent and manage PM2.5 pollution.