Regional features of long-term exposure to PM2.5 air quality over Asia under ssp scenarios based on CMIP6 models

Shim, Sungbo and Sung, Hyunmin and Kwon, Sanghoon and Kim, Jisun and Lee, Jaehee and Sun, Minah and Song, Jaeyoung and Ha, Jongchul and Byun, Younghwa and Kim, Yeonhee and Turnock, Steven T. and Stevenson, David S. and Allen, Robert J. and O’connor, Fiona M. and Teixeira, Joao C. and Williams, Jonny and Johnson, Ben and Keeble, James and Mulcahy, Jane and Zeng, Guang (2021) Regional features of long-term exposure to PM2.5 air quality over Asia under ssp scenarios based on CMIP6 models. International Journal of Environmental Research and Public Health, 18 (13): 6817. ISSN 1661-7827

Abstract

This study investigates changes in fine particulate matter (PM2.5) concentration and air-quality index (AQI) in Asia using nine different Coupled Model Inter-Comparison Project 6 (CMIP6) climate model ensembles from historical and future scenarios under shared socioeconomic pathways (SSPs). The results indicated that the estimated present-day PM2.5 concentrations were comparable to satellite-derived data. Overall, the PM2.5 concentrations of the analyzed regions exceeded the WHO air-quality guidelines, particularly in East Asia and South Asia. In future SSP scenarios that consider the implementation of significant air-quality controls (SSP1-2.6, SSP5-8.5) and medium air-quality controls (SSP2-4.5), the annual PM2.5 levels were predicted to substantially reduce (by 46% to around 66% of the present-day levels) in East Asia, resulting in a significant improvement in the AQI values in the mid-future. Conversely, weak air pollution controls considered in the SSP3-7.0 scenario resulted in poor AQI values in China and India. Moreover, a predicted increase in the percentage of aged populations (>65 years) in these regions, coupled with high AQI values, may increase the risk of premature deaths in the future. This study also examined the regional impact of PM2.5 mitigations on downward shortwave energy and surface air temperature. Our results revealed that, although significant air pollution controls can reduce long-term exposure to PM2.5, it may also contribute to the warming of near-and mid-future climates.