Regional Features of Long-Term Exposure to PM_2.5 Air Quality over Asia under SSP Scenarios Based on CMIP6 Models

• Main Authors: Sungbo Shim, Hyunmin Sung, Sanghoon Kwon, Jisun Kim, Jaehee Lee, Minah Sun, Jaeyoung Song, Jongchul Ha, Younghwa Byun, Yeonhee Kim, Steven T. Turnock, David S. Stevenson, Robert J. Allen, Fiona M. O’Connor, Joao C. Teixeira, Jonny Williams, Ben Johnson, James Keeble, Jane Mulcahy, Guang Zeng
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: CMIP6; SSP scenarios; PM_2.5; air quality index; Asia; climate changes
• Online Access: https://www.mdpi.com/1660-4601/18/13/6817
• ISSN: 1661-7827; 1660-4601

This study investigates changes in fine particulate matter (PM_2.5) 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 PM_2.5 concentrations were comparable to satellite-derived data. Overall, the PM_2.5 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 PM_2.5 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 PM_2.5 mitigations on downward shortwave energy and surface air temperature. Our results revealed that, although significant air pollution controls can reduce long-term exposure to PM_2.5, it may also contribute to the warming of near- and mid-future climates.