Biomass Combustion Produces Hormone-like Pollutants: An Ignored Source

Biomass burning, including household fuels and wildfires, affects billions globally, yet the unique health-related chemical components of PM2.5 emitted from these sources remain poorly understood. Here, we demonstrate that combustion of biomass—yak dung and pine—generates abundant hormone-like components within PM2.5, including natural, synthetic steroids and endocrine disruptors such as estradiol, testosterone enanthate and bisphenol A. Integrated network toxicology and whole-transcriptome sequencing reveal that these hormone compounds may exert distinct, fuel-specific respiratory toxicity by targeting critical genes (e.g., HIF1A or INHBA), functions (e.g., regulation of progesterone secretion or protein serine/threonine kinase activity) and pathways (e.g., vitamin digestion and absorption or RNA polymerase) via multi-level RNA regulation and mutagenic events. Our modelling estimates that mitigating this exposure could prevent ~66,000 premature deaths and yield economic benefits exceeding $11 billion annually. These findings uncover a previously unrecognized class of environmental hormonal pollutants generated by biomass combustion, redefine the health risks of air pollution, and provide a mechanistic foundation for advancing environmental justice and achieving Sustainable Development Goals in vulnerable populations worldwide.