Wildfires and Human Health: Evidence from 15 Wildfire Seasons in Chile

Wildfires are increasing in frequency and intensity. We study the impact of exposure to wildfires on air pollutants and on human health in Chile, finding substantial impacts on both classes of outcomes. We use data on 15 wildfire seasons (2004-2018) matched with granular (intra-day) records of wind direction and air quality, as well as administrative records of all hospitalizations in the country. By combining the precise location of fires with wind direction at the moment in which fires occur, we estimate causal impacts of exposure to wildfires. We find considerable impacts. Exposure to a large wildfire (250 Ha) is observed to increase PM2:5 concentrations by 10% on average in municipalities up to 200km from
the epicenter of the wildfire. These effects have appreciable impacts on rates of hospitalization. A one standard deviation increase in exposure to large wildfires is estimated to increase rates of respiratory hospitalizations by 0.75%, while the effect of exposure to the most extreme week of wildfires observed is estimated to increase hospitalizations by as much as a third. Effects are found to be particularly acute for infants, and to grow with the size of the exposure to wildfire (both in terms of duration and area burned).