Impact of Spatial structure of urban agglomerations on green innovation in China

Monocentric and polycentric configurations represent two distinct spatial structures within urban agglomerations (UAs). Determining which structure more effectively fosters green innovation (GI) is crucial for guiding spatial planning and sustainable development in these urban areas. This study examines 19 Chinese UAs from 2007 to 2021, utilizing night light data to quantify the spatial structure of UA via primacy index and employing the number of green patents as a proxy for the level of GI, utilizing an individual and time two-way fixed effects model to explore the spillover effects of these spatial structures on GI. Findings reveal that across all UAs studied, a monocentric structure is more favorable for GI, a conclusion supported by robustness tests. Results vary across different UA types: The spatial structure of national and regional UAs has no significant impact on GI, whereas a monocentric structure significantly enhances GI in local UAs. The study also finds that UA spatial structures impact GI indirectly through mechanisms of traffic integration and environment regulation. Here, traffic integration exerts a positive mediating effect, while environment regulation serves as a negative mediator.