Improved estimation of particulate matter in China based on multisource data fusion.

Particulate matter (PM) is a global health concern and causes millions of premature deaths worldwide annually. High-resolution and full-coverage PM datasets are essential to support the accurate assessment of PM exposure. Here, a three-stage model framework is developed based on the Community Multiscale Air Quality (CMAQ) simulations (12 km) and multisource data fusion to estimate 1 km daily PM concentrations across China in 2015, including PM2.5 (<2.5 µm) and PM10 (<10 µm). The three-stage model performs well with cross-validation coefficient of determination (R2) of 0.91 and 0.87, and root mean square error (RMSE) of 17.3 µg/m3 and 27.2 µg/m3 for PM2.5 and PM10, respectively. After data fusion from multiple sources, the concentrations of PM2.5 and PM10 are in better agreement with ground observations compared to the CMAQ simulation with RMSE reduced by 72 % and 67 %. High PM2.5 events mainly occur in the North China Plain, Yangtze River Delta, and Sichuan Basin, and PM10 show similar spatial patterns to PM2.5 in eastern China. These full-coverage PM datasets enable in-depth analysis of PM pollution over small areas and support future epidemiological studies and health assessments.