The risks to human health of air toxics, PM2.5, and ozone from the 2023 Canadian wildfires (TEPM 2026)
Citation:
Pye, Havala O. T., William T. Hutzell, Neal L. Fann, T. Nash Skipper, M. Pye, J. Beidler, C. Allen, Benjamin N. Murphy, Emma L. D'Ambro, S. Lin, K. Talgo, L. Reynolds, D. Kang, J. Bash, Karl M. Seltzer, Sara L. Farrell, K. Wyat Appel, K. Brehme, R. Gilliam, Barron H. Henderson, AND A. Chan. The risks to human health of air toxics, PM2.5, and ozone from the 2023 Canadian wildfires (TEPM 2026). R5 Tribal Environmental Professional Managers (TEPM) conference, Durham, NC, March 10, 2026.
Impact/Purpose:
This work achieves multiple objectives in support of key statutory requirements for modeling of air pollutants under the Clean Air Act (42 U.S. Code Chapter 85 Subchapter I Part A). Specifically, this work is the initial development and use of a new capability in CMAQ to track 63 different hazardous air pollutants (HAPs) within the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM). This work also provides insight into the 2023 Canadian fires and their ambient air inhalation impacts across a large geographical area. The supporting data includes an extensive set of model inputs for simulating air quality across the U.S. and Canada for 2023 which can enable additional analysis on the impact of transfer of pollution between the U.S. and Canada and wildfires.
Description:
The 2023 Canadian wildfires resulted in substantial emissions to air. In this work, we used predicted concentrations of hazardous air pollutants (HAPs), fine particulate matter (PM2.5), and ozone across the U.S. and Canada to estimate the potential impacts of 2023 Canadian wildfire smoke on human health. HAPs from Canadian wildfires were estimated to increase lifetime population-weighted cancer inhalation risk by 1.3-in-a-million and noncancer risk by a hazard index (HI) of 0.05 across the domain. The additional risk from smoke was predicted to be above a cancer risk of 100-in-1 million for 1,300 people and a HI of one for 110,000 people, all in Canada.