Measurements of VOCs in Homes Impacted by Smoke from the Marshall Fire

WILLIAM DRESSER, Alexander Bradley, Abby Koss, Joost de Gouw, CU Boulder

     Abstract Number: 339
     Working Group: Biomass Combustion: Outdoor/Indoor Transport and Indoor Air Quality

Abstract
The Marshall Fire was one of the most destructive fires in Colorado history, and burned and damaged over 1000 structures in Boulder County. In the immediate aftermath of the fire, there was an intense interest in understanding the persistent air quality effects of the fire both due to its close proximity to unburned homes as well as the unique nature of the fire, in which mostly man-made materials burned as opposed to biomass. While smoke emissions from traditional wildfires have been well studied and characterized, the emissions from building materials are less well understood and can vary significantly based on the composition. We are interested in how the smoke from this fire infiltrated and then interacted in indoor environments, which have large surface reservoirs, leading to noticeable, persistent indoor air quality effects. In the weeks following the fire, multiple instruments were deployed in a smoke-impacted home immediately adjacent to one of the burn areas to monitor effects. Our measurements quantified gas-phase Volatile Organic Compounds (VOCs) and were carried out with a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOFMS) and an Aerodyne Gas Chromatograph (GC). Both indoor and outdoor levels were measured to quantify indoor enhancements and the long-term trends therein. Ventilation experiments as well as mitigation tests using Corsi-Rosenthal boxes were done and analyzed with respect to changes in indoor VOC concentration. These experiments can also give insight into indoor reservoirs of VOCs and compared to findings in non-smoke impacted indoor environments. Break-down products expected from pyrolysis of compounds in homes, such as brominated flame retardants, were investigated. Quantification was done to inform VOC exposure after the fire compared to known health and safety values.