Beyond the Core: Pollution Dynamics in Peripheral Cities Amidst Deepening Functional Division in Urban Agglomerations

Peripheral cities play a crucial role in the innovative development of urban agglomerations (UAs). However, the environmental impacts on peripheral cities during UA development are not well understood. Utilizing data from the Yangtze River Delta UA in China from 2003 to 2021, this study investigates the pollution dynamics in peripheral cities amidst the deepening functional division within UAs. Furthermore, we identify the mechanisms and contextual factors shaping these dynamics. Our nonlinear panel data regression model reveals an inverted U-shaped trend in pollution emissions both in scale and density in peripheral cities as the UA functional division deepens. Moreover, results from the nonlinear mediation effect models show that economic scale expansion driven by functional division significantly increases pollution in peripheral cities, whereas industrial structure optimization and production technology upgrade caused by functional division contribute to pollution reduction in these cities. Further analyses indicate that enhanced transportation infrastructure and improved information network connectivity can amplify the positive effects of functional division on pollution reduction in peripheral cities. These insights are crucial for developing effective urban division systems and fostering sustainable and innovative development of peripheral cities within UAs.