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Impacts of Aging and Relative Humidity on Biomass Burning Smoke in an Indoor Environment



Marina Vance, Liora Mael, Sofie Schwink, Kathryn Mayer, Thomas Dunnington, Maximilian Schmid, Nicholas Gotlib, Andrew Martin, Dustin Poppendieck, Delphine Farmer


We studied the impacts of aging and relative humidity on simulated wildfire smoke in a test house during the Chemical Assessments of Surfaces and Air (CASA) study. We injected fresh and ozone-aged biomass burning smoke into the test house during times of low (40-45%) and high (75-85%) indoor relative humidity (RH) conditions. Smoke particles, both aged and fresh, were less hygroscopic than indoor and outdoor backgrounds. The outdoor background aerosol was more hygroscopic than the house background, consistent with a higher inorganic fraction. Follow-up experiments in the laboratory showed that aged smoke had a higher aerosol liquid water content than fresh. Furthermore, we found that while aging did not affect aerosol effective density, exposure to higher relative humidity led to an increase in this parameter, suggesting that exposure to water changes the structure of smoke particle aggregates in an irreversible manner.
Proceedings Title
Indoor Air 2024 Proceedings
Conference Dates
July 7-11, 2024
Conference Location
Honolulu, HI, US
Conference Title
Indoor Air 2024


Wildfire, particulate matter, hygroscopicity, indoor aerosol, indoor air quality


Vance, M. , Mael, L. , Schwink, S. , Mayer, K. , Dunnington, T. , Schmid, M. , Gotlib, N. , Martin, A. , Poppendieck, D. and Farmer, D. (2024), Impacts of Aging and Relative Humidity on Biomass Burning Smoke in an Indoor Environment, Indoor Air 2024 Proceedings, Honolulu, HI, US, [online], (Accessed July 13, 2024)


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Created July 8, 2024, Updated March 8, 2024