Beyond the haze: Decomposing the effect of economic inequality on global air quality from 2000 to 2020

Extant research has analysed the macroeconomic and political drivers of worldwide air pollution. Empirically, studies have focused on either between-country (cross-national comparisons) or within-country (temporal changes) dynamics, but these related effects have not been simultaneously addressed. Employing a comprehensive dataset spanning 156 countries over two decades (2000−2020), we take a distinctive dual approach to examine the effects of economic inequality, economic development, and democratic institutions on air pollution exposure within and across countries. First, against expectations, we find that within countries over time, increases in economic inequality correlate with reduced air pollution. This relationship remains consistent irrespective of country-level economic development or democratic status. Further we find that the trajectory of economic inequality conditions this effect, suggesting that whether redistributive measures towards addressing economic inequality carry environmental co-benefits or trade-offs likely depends upon the context. Second, between countries, economic inequality has a limited association with air pollution levels. Third, the effects of economic inequality on air pollution levels within and between countries are substantively small in comparison to the impact of economic development and democracy. This study emphasises the need to reconsider conventional expectations regarding economic inequality, further accentuating the influence of economic development and democratic institutions.