Synergy level of pollution and carbon reduction in the Yangtze River Economic Belt: Spatial-temporal evolution characteristics and driving factors

Achieving synergistic control of air pollution and carbon emissions is crucial for addressing environmental changes. This study aims to assess the synergy level of pollution and carbon reduction, identify driving factors, and provide realization paths to reduce pollution and carbon emissions synergistically. Using a coupling coordination degree model and optimal parameters-based Geographical detector model, this study focuses on 108 cities in the Yangtze River Economic Belt. Results reveal that PM2.5 control is more effective than carbon emission management in the YREB. The synergy level of pollution and carbon reduction shows an upward trend with the mean synergy level increasing 7.2% from 2006 to 2019. Spatially, significant heterogeneity exists, with higher synergy degrees in upstream areas. Social and natural factors including industrial structure, technological innovation, energy structure, human capital, and economic foundation significantly influence pollution and carbon reduction synergy. The interaction between natural constraints and high-quality development factors such as technological innovation and the digital economy further strengthens the driving force, with the strengthening of a single factor reaching up to 75%. Based on regional differences in synergy levels, this study proposes targeted applicable suggestions, including strengthening inter-city interaction, optimizing regional industrial and energy structures, and promoting technological innovation.