Wildfire, Smoke and Mental Health in Canada

This study examines the relationship between wildfires and mental health-related hospitalizations in Canada from 2006 to 2018. Most previous estimates of the mental health costs of wildfire have focused on the impacts of exposure to PM₂.₅. We break new ground by highlighting other pathways for wildfires to affect mental health, including evacuation orders, direct local costs of fires, and climate anxiety, which is proxied using wildfire-related Twitter activity. We find that all these mechanisms affect mental health-related hospitalizations, with especially large impacts on hospitalizations for anxiety and substance abuse. Conditional on air quality, wildfire events that draw national attention worsen the mental health of susceptible people, even when they live far away. Elderly people and those with pre-existing health conditions that make them more vulnerable, are more strongly affected. The results indicate that climate anxiety stoked by wildfire events may account for much of the overall mental health cost. Accounting for these additional mechanisms does little to diminish the estimated effect of PM ₂.₅ from wildfire smoke, however, suggesting that the additional factors have effects on mental health that are in addition to those of PM₂.₅.