Wildfire Smoke Causes About 40,000 U.S. Deaths Annually

A Stanford-led analysis using 20 years of death records, satellite data and climate models finds wildfire smoke currently causes roughly 40,000 U.S. deaths per year and could exceed 70,000 excess deaths annually by midcentury under worst-case climate scenarios. The study projects state-level impacts — for example, Oregon could see about 831 excess deaths and California around 5,000 of the projected increase. Wildfire smoke's fine particulate matter (PM2.5) is linked to asthma, heart disease and lung disease, and researchers found elevated mortality can persist up to three years after heavy smoke exposure. Extreme fires across North America, including Canadian blazes, can carry smoke far beyond burn zones, increasing exposure in regions not prone to fires. The authors estimate the resulting health burden could cost hundreds of billions in healthcare and lost productivity if trends continue. They stress these are projections, not inevitabilities, and say cutting greenhouse gases, improving forest management and strengthening public-health protections (air filters, masks and warnings) can substantially reduce the projected toll.