Regional Features of Long-Term Exposure to PM2.5 Air Quality over Asia under SSP Scenarios Based on CMIP6 Models

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.

Global PM2.5 Prediction and Associated Mortality to 2100 under Different Climate Change Scenarios

“…Most studies , on PM 2.5 concentration estimation under different climate scenarios have been based on the Coupled Model Intercomparison Project 5 (CMIP5) Representative Concentration Pathways scenarios. However, with the release of the CMIP6 simulation results, the Scenario Model Intercomparison Project provides new alternative scenarios that are intimately connected with societal concerns regarding climate change mitigation, adaptation, and impacts. , Some studies have estimated future air quality based on CMIP6 climate projections; , however, these studies either investigated the PM 2.5 exposure in only one country or region, − or the predicted periods were shorter than 50 years. , Although future global-scale PM 2.5 simulations are available, , the low model spatial resolution (e.g., 1.875° × 1.25°) limits the ability to accurately capture the spatial variability of PM 2.5 concentration, particularly at the city scale. As yet, no comprehensive study has estimated the global mortality burden associated with ambient PM 2.5 based on high-resolution (e.g., 0.1° × 0.1°) and bias-corrected future climate projections that incorporate demographic and emission data.…”

“…However, with the release of the CMIP6 simulation results, the Scenario Model Intercomparison Project provides new alternative scenarios that are intimately connected with societal concerns regarding climate change mitigation, adaptation, and impacts. 9,10 Some studies have estimated future air quality based on CMIP6 climate projections; 11,12 however, these studies either investigated the PM 2.5 exposure in only one country or region, 11−13 or the predicted periods were shorter than 50 years. 14,15 Although future global-scale PM 2.5 simulations are available, 12,16 the low model spatial resolution (e.g., 1.875°× 1.25°) limits the ability to accurately capture the spatial variability of PM 2.5 concentration, particularly at the city scale.…”

Inequalities in Air Pollution Exposure and Attributable Mortality in a Low Carbon Future

“…A number of specific measures that would likely yield the largest co‐benefits for climate and air quality have been highlighted in recent reports (Royal Society, 2021; UNEP, 2019; UNESCAP, 2023). Overall, the greatest health benefits are likely to result from implementation of climate mitigation policies in combination with stringent air pollution control measures (Amann et al., 2020; Conibear, Reddington, Silver, Arnold, et al., 2022; Harmsen et al., 2020; Likhvar et al., 2015; Partanen et al., 2018; Rafaj et al., 2021; Rao et al., 2016; Shim et al., 2021).…”

“…The new Shared Socioeconomic Pathways (SSPs) (O'Neill et al., 2014) combine a range of potential future climate policies with varying degrees of air pollution control (Rao et al., 2016). Recent studies have assessed the impacts of the SSPs on global air quality (Allen et al., 2020; Shim et al., 2021; Turnock et al., 2020) and public health in Africa (Shindell et al., 2022), China (Wang et al., 2022) and globally (Turnock et al., 2023; Yang et al., 2023), demonstrating that strong mitigation of both climate and air pollutants in the SSPs could yield large reductions in PM 2.5 concentrations across all world regions. Turnock et al.…”

“…The new Shared Socioeconomic Pathways (SSPs) (O'Neill et al, 2014) combine a range of potential future climate policies with varying degrees of air pollution control (Rao et al, 2016). Recent studies have assessed the impacts of the SSPs on global air quality (Allen et al, 2020;Shim et al, 2021;Turnock et al, 2020) and public health in Africa (Shindell et al, 2022), China (Wang et al, 2022) and globally (Turnock et al, 2023;Yang et al, 2023), demonstrating that strong mitigation of both climate and air pollutants in the SSPs could yield large reductions in PM 2.5 concentrations across all world regions. Turnock et al (2023) showed that there are potential penalties to the future air pollution health burden in some world regions due to a warming climate that could offset benefits from reductions in air pollutant emissions, highlighting the importance of mitigating both climate and anthropogenic air pollution sources simultaneously.…”