Pollutant emission reductions deliver decreased PM2.5-caused mortality across China during 2015-2017

Air pollution is a serious environmental issue and leading contributor to disease burden in China. Rapid reductions in fine particulate matter (PM2.5) concentrations and increased ozone concentrations occurred across China during 2015 to 2017. We used measurements of particulate matter with a diameter < 2.5 mu m (PM2.5) and ozone (O-3) from more than 1000 stations across China along with Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) regional air quality simulations, to explore the drivers and impacts of observed trends. The measured nationwide median PM2.5 trend of -3.4 mu gm(-3) yr(-1) was well simulated by the model (-3.5 mu g m(-3) yr(-1)). With anthropogenic emissions fixed at 2015 levels, the simulated trend was much weaker (-0.6 mu g m(-3) yr(-1)), demonstrating that interannual variability in meteorology played a minor role in the observed PM2.5 trend. The model simulated increased ozone concentrations in line with the measurements but underestimated the magnitude of the observed absolute trend by a factor of 2. We combined simulated trends in PM2.5 concentrations with an exposure-response function to estimate that reductions in PM2.5 concentrations over this period have reduced PM2.5-attributable premature mortality across China by 150 000 deaths yr(-1)