Evaluation of the Coupling Coordination Degree Between PM 2.5 and Urbanization Level: A Case in Guangdong Province

PM 2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 µm) pollution is one of the most common problems triggered by the acceleration of urbanization. The coordinated development of cities and the environment has been a topic of significant interest in recent years. Based on the spatiotemporal relationship between the evolution of urbanization levels and PM 2.5 concentrations, and starting from multiple factors characterizing urbanization, this study constructs a coupling coordination degree model between PM 2.5 and urbanization levels to explore the interaction and degree of coordination between urbanization and PM 2.5 in Guangdong Province from 2000 to 2021. The research reveals that the conflict between the urbanization process and PM 2.5 pollution in various cities of Guangdong Province is gradually easing. The year 2011 was a turning point as the PM 2.5 pollution levels in cities that were in an uncoordinated phase began to improve. The coupling coordination degree between urbanization and PM 2.5 pollution in Guangdong Province exhibits significant spatial heterogeneity. The coupling coordination degree in most coastal cities is higher than that in inland cities. Cities in economically underdeveloped regions also face relatively lower pressure from pollution emissions. These regions are characterized by lagging urbanization, and their coupling coordination degree is slowly increasing as urbanization progresses. In economically developed regions, the coupling coordination degree between urbanization levels and PM 2.5 pollution has reached a basic level of coordination, although the specific types vary.