The Impacts of Changes in Near-Term Climate Forcers on East Asia’s Climate

This study investigates the impacts of near-term climate forcers (NTCFs) and ozone precursor emissions on particulate matter (PM2.5) concentrations in East Asia (EA). Our analysis used the Coupled Model Intercomparison Project Phase 6 Aerosols and Chemistry Model Intercomparison Project (AerChemMIP) dataset to assess the potential changes in air quality under varying emission scenarios for the present day (1995–2014) and near-term future (2015–2054). Present-day PM2.5 concentrations in EA averaged 14.3 ± 2.6 μg/m3, with significant regional variation: East China (32.43 μg/m3), Korea (13.71 μg/m3), and Japan (7.51 μg/m3). A reduction in historical NTCF emissions would lower PM2.5 concentrations by approximately 43% across EA, whereas reducing O3 precursors would yield an approximately 10% decrease. Under the SSP370 scenario, PM2.5 concentrations are projected to increase by 16% in the near-term future (2045–2054). However, robust NTCF mitigation could reduce PM2.5 levels by approximately 40%, primarily by decreasing sulfate and organic aerosols, which are the dominant contributors of historical PM2.5 variability. Despite substantial projected improvements, achieving the World Health Organization’s stringent air quality guidelines remains challenging, highlighting the necessity for enhanced emissions control targeting key pollutant sources. These insights are crucial to East Asian policymakers aiming to implement effective air quality management strategies.