Climate-Driven Escalationof Global PM_2.5 Health Burden from Wildland Fires

Wildland fires constitute a major source of ambient fine particulate matter (PM_2.5), significantly impacting air quality and public health. As the climate becomes warmer and drier, fire frequency is projected to rise, yet how the associated health impacts of fire-sourced PM_2.5 (FPM_2.5) respond to climate change remains vague. In this study, we modeled the global concentration and associated premature deaths of FPM_2.5 over the past two decades. Our results reveal an upward trend in FPM_2.5 concentrations globally, contributing to an increase in premature deaths from 156,000 to 241,000 between 2000 and 2021, alongside population growth and aging. Substantial variations are observed on a regional scale, but most regions experience increasing exposure levels, suggesting an increased impact of FPM_2.5. Further regression analysis indicates that climate change plays a critical role in these trends, accounting for 56% of the net changes in FPM_2.5-related premature deaths. Warming and drought emerge as key drivers of climate-induced health risks, with slightly different contributions to the FPM_2.5 concentration and the associated premature deaths. Our findings underscore the urgent need to integrate climate adaptation strategies with fire management to mitigate the growing health burden caused by FPM_2.5 worldwide.