Rapid improvement of PM2.5 pollution and associated health benefits in China during 2013-2017

Exposure to fine particulate matter (PM2.5) is known to harm public health. In China, after implementation of aggressive emissions control measures under the Action Plan of Air Pollution Prevention and Control (2013-2017), air quality has significantly improved. In this work, we investigated changes in PM2.5 exposure and the associated health impacts in China for the period 2013-2017. We used an optimal estimator of PM2.5 combining in-situ observations, satellite measurements, and simulations from a chemical transport model to derive the spatial and temporal variations in PM2.5 exposure, and then used well-developed exposure-response functions to estimate the premature deaths attributable to PM2.5 exposure. We found that national population-weighed annual mean PM2.5 concentrations decreased from 67.4 mu g m(-3) in 2013 to 45.5 mu g m(-3) in 2017 (32% reduction). This rapid decrease in PM2.5 pollution led to a 14% reduction in premature deaths due to long-term exposure. We estimated that, during 2013-2017, the premature deaths attributable to long-term PM2.5 exposure decreased from 1.2 million (95% CI: 1.0, 1.3; fraction of total mortality: 13%) in 2013 to 1.0 million (95% CI: 0.9, 1.2; 10%) in 2017. Despite the rapid decrease in annual mean PM2.5 concentrations, health benefits associated with reduced long-term exposure were limited, because for many cities, the PM2.5 levels remain at the portion where the exposure-response function is less steeper than that at the low-concentration end. We also found that the deaths associated with acute exposure decreased by 61% during 2013-2017 due to rapid reduction in the number of heavily polluted days. Our results confirm that clean air policies in China have mitigated the air pollution crisis; however, continuous emissions reduction efforts are required to protect citizens from air pollution.