Co-exposure patterns of heat, wildfire, and wildfire smoke in Western US

Climate change drives three heat-related natural hazards: extreme heat, wildfire burn zones, and wildfire smoke. Using daily census tract-level data from 2006-2020, we investigated when, where, and who these three hazards co-exposed in eleven Western US states. Among 18,108 tracts, an average of 32 days per year saw at least one of three hazards. Extreme heat and wildfire smoke co-occurred most frequently, with tracts experiencing this dual exposure an average of 2 tract-days per year. Incidence of extreme heat and wildfire smoke days individually increased over time, but none of the co-exposures demonstrated an increasing trend, and their spatial patterns differed significantly from individual exposures.