Synergistic Evolution of PM 2.5 and O 3 Concentrations: Evidence from Environmental Kuznets Curve Tests in the Yellow River Basin.

Air pollution, especially the synergistic pollution of PM_2.5 and O₃, poses a severe threat to human life and production. The synergistic formation mechanism of PM_2.5 and O₃ pollution is relatively confirmed, while research on their spatiotemporal synergy is urgent. Based on remotely sensed interpretation data from 90 cities in the Yellow River Basin, we analyzed the synergistic evolution of PM_2.5 and O₃ concentrations during 2013–2020. Combined with the environmental Kuznets curve, we performed factor analysis using a panel regression model. The synergistic evolution pattern shows a gradual decrease in PM_2.5 concentration and a gradual increase in O₃ concentration. There is a strong spatial auto-correlation in the two pollutants' concentrations. The relationship between economy and PM_2.5 concentration shows an "N-shaped" curve, while that between O₃ concentration and economic development presents an inverse "N-shaped" curve. The environmental Kuznets curve shows that the deterioration of O₃ pollution takes place later than the mitigation of PM_2.5 pollution. Various factors have obvious heterogeneous effects on PM_2.5 and O₃ concentrations. Meanwhile, the sensitivity effect of per capita GDP on PM_2.5 concentration in the midstream region is stronger than that in the upstream region, while the sensitivity effect of per capita GDP on O₃ concentration is strongest in the midstream region than that in upstream and downstream region. [ABSTRACT FROM AUTHOR]