Comparison of Current and Future PM2.5 Air Quality in China Under CMIP6 and DPEC Emission Scenarios

Abstract: The sixth Coupled Model Intercomparison Project (CMIP6) scenarios provide opportunities to explore global climate and pollution mitigation pathways with socioeconomic features, but they might be limited on regional-scale projections due to inadequate consideration of local policies. Here, we simulated China's PM2.5 air quality with local policy-based scenarios (Dynamic Projection for Emissions in China (DPEC)) and the CMIP6 scenarios. We found both emission inventories can reproduce China's base-year PM2.5 and chemical aerosols while using DPEC emissions could better match in-situ observations. In addition, DPEC mitigation scenarios can better capture China's PM2.5 decline during 2015–2019 (22% under SSP2-45-policy and 30% under SSP1-26-best) with observations (∼28%) than CMIP6 emissions. With the effects of current-year bias and inadequate considerations of pollution control policies, PM2.5 projections in 2030 and 2050 with CMIP6 mitigation scenarios are 42%–48% (9–13 μg/m3) and 59%–73% (8–12 μg/m3) higher than projections with DEPC. Our study suggests the community should incorporate more region-specific environmental policy in future scenario designs.