By Qian Zhang, UL Research Institutes
Wildfires have increased in intensity and burned area over the past decades, which result in emissions of air pollutants that are aged during transport over time. Fine particulate matter (PM2.5), as a major component of wildfire smoke, is associated with health concerns and premature mortality. This recently published paper by Joo et al. investigated the change of smoke chemical compositions during Canadian wildfire smoke transport to New York City in 2023. In addition, this study linked health risks to smoke components during 1 to over 6 days of transport.
The chemical compositions of smoke PM2.5 were analyzed by aerosol mass spectrometry for organic and inorganic components and energy dispersive X-ray fluorescence for metals, and then source apportionment analysis was conducted using positive matrix factorization. Results showed that compared to non-smoke conditions, the smoke transport from the Quebec wildfire resulted in increased levels of PM2.5, organic aerosol (OA), black carbon, formaldehyde and trace elements for approximately 5 to 25 folds, and OA was the predominant component of PM2.5. In addition, non-dust potassium concentration showed the strongest correlation with smoke-related OA compared to other biomass burning pollutants. An epidemiologic model was used to evaluate the health risks of residences downwind associated with wildfire smoke transport. The results showed that asthma emergency department visits were strongly associated with concentrations of PM2.5, total smoke-related OA, and non-dust potassium. Estimated oxidative stress was also elevated for each smoke transport event compared to background conditions.
Increased wildfires not only worsen air quality but may also negatively affect human health. This study shows a significant association between wildfire smoke aging and asthma exacerbations and enhancements of in-lung oxidative stress, which demonstrates elevated health risks with increasingly frequent smoke episodes. This study emphasizes the impacts of aged biomass burning PM2.5 outside of the peak episodes, which needs to be evaluated using real-time chemically resolved monitoring.
Read more in the literature:
Joo, T.; Rogers, M. J.; Soong, C.; Hass-Mitchell, T.; Heo, S.; Bell, M. L.; Ng, N. L.; Gentner, D. R. Aged and Obscured Wildfire Smoke Associated with Downwind Health Risks. Environ. Sci. Technol. Lett. 2024. https://doi.org/10.1021/acs.estlett.4c00785.
This Issue’s Newsletter Committee:
Editor | Sarah Petters, University of California, Riverside
Senior Assistant Editor | Lindsay Yee, University of California, Berkeley
Junior Assistant Editor | Qian Zhang, UL Research Institute
Junior Assistant Editor | Robert Nishida, University of Waterloo