Impacts of 2000-2050 Climate Change on Fine Particulate Matter (PM2. 5) Air Quality in China Based on Statistical Projections Using an Ensemble of Global Climate Models

Fine particulate matter (PM2. 5) air quality is strongly dependent on not only on emissions but also meteorological conditions. Here we examine the dominant synoptic circulation patterns that control day-to-day PM2. 5 variability over China. We perform principal component (PC) analysis on 1998-2016 NCEP/NCAR Reanalysis I daily meteorological fields to diagnose distinct synoptic meteorological modes, and perform PC regression on spatially interpolated 2014-2016 daily mean PM2. 5 concentrations in China to identify modes dominantly explaining PM2. 5 variability. We find that synoptic systems, eg, cold-frontal passages, maritime inflow and frontal precipitation, can explain up to 40% of the day-to-day PM2. 5 variability in major metropolitan regions in China. We further investigate how annually changing frequencies of synoptic systems, as well as changing local meteorology, drive interannual PM2. 5 …