Wildfire, Smoke and Mental Health in Canada

Most previous estimates of the effects of wildfire on mental health have focused on the impact of exposure to PM2.5, which often travels long distances. We break new ground by highlighting additional impacts of wildfires on mental health, including through evacuation orders, local costs of fires, and climate anxiety, which is proxied using news reports of distant fires. All these mechanisms affect mental health-related hospitalizations, with especially large impacts on hospitalizations for anxiety and substance abuse. Conditional on local 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. Accounting for these additional mechanisms does little to diminish the estimated effect of PM2.5 from wildfire smoke, but raises the estimated impact of fires on mental health 75%, suggesting that increases in PM2.5 are not the only important mechanism.