Health Impact Analysis of Wildfire Smoke-PM_2.5 in Canada (2019-2023)

Wildfires are a source of air pollution, including PM_2.5. Exposure to PM_2.5 from wildfire smoke is associated with adverse health effects including premature death and respiratory morbidity. Air quality modeling was performed to quantify seasonal wildfire-PM_2.5 exposure across Canada for 2019-2023, and the annual acute and chronic health impacts and economic valuation due to wildfire-PM_2.5 exposure were estimated. Exposure to wildfire-PM_2.5 varied geospatially and temporally. For 2019-2023, the annual premature deaths attributable to wildfire-PM_2.5 ranged from 49 (95% CI: 0-73) to 400 (95% CI: 0-590) due to acute exposure and 660 (95% CI: 340-980) to 5,400 (95% CI: 2,800-7,900) due to chronic exposure, along with numerous non-fatal cardiorespiratory health outcomes. Per year, the economic valuation of the health burden ranged from $550M (95% CI: $19M-$1.2B) to $4.4B (95% CI: $150M-$9.9B) for acute impacts and $6.4B (95% CI: $2.2B-$12.9B) to $52B (95% CI: $18B-$100B) for chronic impacts. Additionally, a long-term average annual exposure for 2013-2023 was estimated using air quality modeling. From this, more than 80% of the population had an average seasonal wildfire-PM_2.5 exposure of at least 1.0 μg/m³ and there were 1,900 (95% CI: 980-2,800) attributable premature deaths and a total economic valuation of $18B (95% CI: $6.1B-$36B), per year. Evaluating and understanding the health impacts of wildfire-PM_2.5 is important given the sizable contribution of wildfire smoke to air pollution in Canada, as well as the anticipated increases in wildfire activity due to climate change.