Tightening standards for indoor levels of PM2.5: A promising approach for reducing PM2.5 associated mortalities in Urban China
“Healthy building” standards or guidelines have been established to reduce indoor PM2.5 exposure by limiting indoor concentrations. We estimate premature adult mortalities attributed to PM2.5 across urban China in 2015 and the corresponding mortality reductions achieved by meeting the yearly-averaged indoor PM2.5 threshold in the newly established Assessment Standard for Healthy Building (ASHB) and seven other potential target thresholds. We use outdoor PM2.5 concentrations from 1497 monitoring sites in 366 cities in China, coupled with a detailed exposure model and an integrated exposure-response model, to estimate exposures to outdoor-origin PM2.5 and associated mortalities. Results indicate that premature mortalities in urban populations attributed to exposures to outdoor-origin PM2.5 were 0.33 million, with indoor exposure accounting for 0.25 million. Potentially, 10,000 deaths could be avoided if indoor PM2.5 concentrations in China met the current ASHB threshold. The analysis in this paper should be helpful in formulating present and future indoor air quality policies.
