Characterization of Emissions from Burned Residue in Post-wildfire Residential Zones: Analytical Approaches for Assessing the Impact of Wildland-Urban Interface (WUI) Fires

YAN WEN, Vera Samburova, Andrey Khlystov, Desert Research Institute

     Abstract Number: 492
     Working Group: Burning Questions of Aerosol Emissions, Chemistry, and Impacts from Wildland-Urban Interface (WUI) Fires

Abstract
Wildfires are becoming increasingly frequent and severe across the western United States. The January 2025 Los Angeles (LA) fire exemplified this trend, devastating neighborhoods and leaving behind long-term environmental and health concerns. The combustion of household materials, electronics, and plastics releases volatile organic compounds (VOCs) and other toxic substances, such as polycyclic aromatic hydrocarbons (PAHs), which can contaminate soil, water, and air across varying spatial and temporal scales. Additionally, charred and pyrolyzed materials in burned areas continue to release harmful substances post-fire through multiple pathways, posing risks to local ecosystems and public health. In this study, we investigate the environmental and health impacts of wildland-urban interface fires after they have been extinguished. Post-fire samples were collected in burned residential zones in LA, including soil, ash, stones, and insulation materials samples. Chemical characterization of degassing from these samples was conducted to assess the release of harmful substances from various post-fire sources. A non-targeted VOCs screening analysis was performed using gas chromatography-ion mobility-quadruple time-of-flight mass spectrometer (GC-IM-QTOF) to identify key toxins and quantify their concentrations in the post-fire emissions. Coupling this approach with multivariate statistical analysis, we enable a comprehensive understanding of the VOCs and their variations in post-fire samples. These insights facilitate further investigations into pollutant persistence, toxicity, and potential mitigation strategies.