Scaling of urban environmental performance in Chinese cities

Modeling how green performance attributes scale over cities of different size reveals how an urban system performs environmentally as a whole, establishes population-adjusted limits for expected urban management targets, identifies cities doing better or worse than expected for their size, and is a starting point for systematically explaining such variation from the mean. This seems a useful contribution to devising strategies for sustainable urban development and environmental management. However, existing studies have focused solely on the scaling of limited pollutants, hindering a comprehensive understanding of urban environmental performance scaling. Our study investigates scaling patterns of urban environmental attributes covering the full cycle of generation-treatment-outcomes on environmental quality of key types of urban pollution and the economic-technical support capacity of cities. We examine 28 environmental performance indicators in seven categories for Chinese cities in 2020. Our findings reveal that 27 indicators show good alignment with urban scaling theory. Larger cities tend to perform better than smaller ones, exhibiting lower per capita pollution generation and carbon emissions, higher environmental investment, stronger technological innovation capabilities, and more efficient waste treatment and recycling. We also find systematic geographical effects, with cities in northeastern and Midwestern China underperforming compared to the national average for their size. Gross domestic product per capita has the most far-reaching impact on variation in population-adjusted urban environmental performance. The study reveals regularities in the relationships between city size and environmental performance, which will improve the sophistication of differentiated pollution control strategies aimed at mitigating human-environment conflicts arising from rapid urbanization.