PM2.5-Associated Premature Mortality Attributable to Hot-And-Polluted Episodes and the Inequality Between the Global North and the Global South

Exposure to air pollution and excessive heat during hot-and-polluted episodes (HPEs) may synergistically cause higher health risks globally. Nevertheless, long-term global spatiotemporal characteristics of HPEs and their health impacts remain unclear. Herein, we conducted statistical analyses using reanalysis data of fine particulate matter (PM_2.5) and climate together with our derived concentration-response function for HPEs to assess global HPE variations from 1990 to 2019, and to estimate the PM_2.5-associated premature mortality during HPEs. Our results reveal that HPE frequency increased significantly globally. HPE PM_2.5 intensity in the Global North continuously increased, overpassing the Global South after 2010, indicating a recurred risk of air pollution under climate change in the Global North after several years of emission control endeavors. Globally, we estimated approximately 694,440 (95% CI: 687,996–715,311) total mortalities associated with acute PM_2.5 exposure during HPEs from 1990 to 2019, with the Global South accounting for around 80% of these deaths. Among the most vulnerable 15 countries, India had by far the highest mortality burden, and the United States, Russia, Japan, and Germany were particularly highlighted as having higher burdens within the Global North. Our findings highlight the importance of considering environmental inequality between the Global North and the Global South, and co-benefits of air pollution-climate change mitigation during policymaking processes.