“Supply-side structural reform” (SSSR) has been the most important ongoing economic reform in China since 2015, but its important environmental health effects have not been properly assessed. The present study addresses that gap by focusing on reduction of overcapacity in the coal, steel, and iron sectors, combined with reduction of emissions of sulfur dioxide (SO2), nitrogen oxide (NOx), and fine particulate matter (PM2.5), and projecting resultant effects on air quality and public health across cities and regions in China. Modeling results indicate that effects on air quality and public health are visible and distributed unevenly across the country. This assessment provides quantitative evidence supporting projections of the transregional distribution of such effects. Such uneven transregional distribution complicates management of air quality and health risks in China. The results challenge approaches that rely solely on cities to improve air quality. The article concludes with suggestions on how to integrate SSSR measures with cities' air quality improvement attainment planning and management performance evaluation