Global fire activity exacerbates extreme PM2.5 pollution

Abstract

Extreme PM2.5 pollution events pose substantial threats to public health and environmental sustainability. However, under climate change, the relationship between global fire activity and extreme PM2.5 pollution remains insufficiently understood. Using 0.25° × 0.25° gridded data from 2004 to 2023, this study employs quantile regression models to assess the influence of global fire activity on extreme PM2.5 pollution. Results show that fire activity has a significant positive relationship with PM2.5 concentrations across all quantiles, with this relationship becoming particularly pronounced under extreme pollution conditions. At the 95th percentile, the fire-related regression coefficient reaches 0.899 (p < 0.05), which is 2.9 and 4.5 times higher than the coefficients at the 50th (0.310) and 10th (0.197) percentiles, respectively. Spatial autocorrelation analysis further reveals that regions where extreme PM2.5 pollution is strongly associated with fire activity exhibit significant spatial clustering (Moran’s I = 0.036, p < 0.01). Notably, Canada in North America, Siberia in Asia, Brazil in South America, and Indonesia in Southeast Asia are identified as the most strongly affected regions. These findings improve understanding of the role of fire activity in extreme PM2.5 pollution and provide important evidence for strengthening global air quality management and emergency response strategies.