Investigation of VOC Emissions and Retention from Wildland Urban Interface Fires

WILLIAM DRESSER, Shantanu Jathar, Christian L'Orange, Joost A. de Gouw, University of Colorado

     Abstract Number: 433
     Working Group: Chemicals of Emerging Concern in Aerosol: Sources, Transformations, and Impacts

Abstract
Wildfires at the wildland-urban interface(WUI) have been increasing over recent decades with the expansion of human development. These fires present a unique set of concerns around the potential production and exposure to novel chemical compounds not traditionally found in biomass fires since the fuel composition includes large amounts of structural materials such as insulation, siding, and plastics. What these structural emissions look like is not as well understood as biomass emissions and important as WUI fire range expands. Additionally, the acute exposure to smoke can not only occur during the event but the proximity of WUI fires to structures means a greater amount of emissions infiltration into indoor air. Enhanced indoor concentrations can then potentially persist due to high surface-to-volume ratios and low air exchange rates. The work presented here focuses on understanding these issues with studies in the laboratory and field focused on measurements of volatile organic compounds (VOCs) using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS). VOCs are of concern for their health risks and potential to form secondary organic aerosols (SOA).

Laboratory measurements were made as part of the Burning Homes and Structural MAterial (BHASMA) study at Colorado State University. Real-time data was collected over multiple burns noting differences in emission profiles over time as well as distinct emission profiles between materials. Field measurements focused on indoor measurements after the Marshall Fire in 2022. Indoor measurements were begun in smoke impacted homes quickly after the fire and lasted for roughly a month following the event allowing for long term analysis of indoor VOC concentrations. The persistence of VOCs was then compared to past work around surface partitioning and indoor studies to better understand the exposure to and evolution of indoor compounds.