Emergency Department Visits Respond Nonlinearly to Wildfire Smoke

Extreme air pollution events, like those from wildfires, negatively affect health through physiological responses but may also be salient enough to induce behavioral changes in individuals protecting their own health. The net impacts of these complex tradeoffs are poorly characterized. By joining the near-universe of emergency department visits in California from 2006 to 2017 with spatially and temporally resolved estimates of ambient wildfire smoke, we find total visits respond nonlinearly to increasing wildfire smoke concentrations, but that response differs by cause of visit. Total visits increase at lower concentrations but then decline at higher concentrations, suggesting that populations shift their behaviors following salient smoke periods. Whereas respiratory-related visits steadily increase, visits for accidental injuries and non-respiratory symptoms like stomach pains decline at high smoke concentrations.