2023
Author(s): Xu R, Ye T, Yue X, Yang Z, Yu W, Zhang Y, Bell ML, Morawska L, Yu P, Zhang Y, Wu Y, Liu Y, Johnston F, Lei Y, Abramson MJ, Guo Y, Li S
Wildfires are thought to be increasing in severity and frequency as a result of climate change(1-5). Air pollution from landscape fires can negatively affect human health(4-6), but human exposure to landscape fire-sourced (LFS) air pollution has not been well characterized at the global scale(7-23). Here, we estimate global daily LFS outdoor fine particulate matter (PM(2.5)) and surface ozone concentrations at 0.25° × 0.25° resolution during the period 2000-2019 with the help of machine learning and chemical transport models. We found that overall population-weighted average LFS PM(2.5) and ozone concentrations were 2.5 µg m(-3) (6.1% of all-source PM(2.5)) and 3.2 µg m(-3) (3.6% of all-source ozone), respectively, in 2010-2019, with a slight increase for PM(2.5), but not for ozone, compared with 2000-2009. Central Africa, Southeast Asia, South America and Siberia experienced the highest LFS PM(2.5) and ozone concentrations. The concentrations of LFS PM(2.5) and ozone were about four times higher in low-income countries than in high-income countries. During the period 2010-2019, 2.18 billion people were exposed to at least 1 day of substantial LFS air pollution per year, with each person in the world having, on average, 9.9 days of exposure per year. These two metrics increased by 6.8% and 2.1%, respectively, compared with 2000-2009. Overall, we find that the global population is increasingly exposed to LFS air pollution, with socioeconomic disparities.
DOI: https://dx.doi.org/10.1038/s41586-023-06398-6