Fire heat affects the impacts of wildfires on air pollution in the United States

• 成果类型: Article
• 署名作者: Ma, Qihan; Wei, Linyi; Wang, Yong; Zhang, Guang J.; Zhou, Xinlin; Wang, Bin
• 署名单位: Fudan University; Tsinghua University; Chinese Academy of Sciences; Institute of Earth Environment, CAS; University of California System; University of California San Diego; Scripps Institution of Oceanography; Chinese Academy of Sciences; Institute of Atmospheric Physics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13950
• DOI: 10.1126/science.ads1957
• 发表日期: 2025-09-11
• 页码: 1137-1142
• 关键词: atmospheric moisture transport; secondary organic aerosol; climate simulations; radiative power; ambient pm2.5; smoke plumes; time-series; emissions; MODEL; forest

摘要

Conventional wisdom suggests that wildfires in the western United States (WUS) degrade air quality nationwide as a result of aerosol emissions and eastward transport. However, we found that heat produced by wildfires, a commonly neglected effect, can reduce fine particle concentrations (PM2.5) in the eastern United States (EUS) by an amount comparable to the increases in the WUS during the fire season. This phenomenon arises from fire heat-induced convection in the WUS and subsequent downstream meteorological changes distant from fires. Enhanced wet deposition and weakened eastward transport of fire aerosols lower PM2.5 levels in the EUS. Therefore, neglecting the effect of fire heat on PM2.5 pollution leads to an overestimate of 1200 additional premature deaths and 3.3 billion USD in economic losses, particularly in the densely populated EUS.