Determination of Polycyclic Aromatic Hydrocarbons from Wildfire Smoke on Indoor Surfaces

Aurelie Laguerre, Brett Stinson, ELLIOTT GALL, Portland State University

     Abstract Number: 227
     Working Group: Biomass Combustion: Outdoor/Indoor Transport and Indoor Air Quality

Abstract
Wildfire events are occurring with increasing frequency, impacting both outdoor and indoor air quality. Wildfires are a substantial source of polycyclic aromatic hydrocarbons (PAHs), a class of compounds with adverse health impacts. Indoor surfaces may accumulate PAHs during an wildfire event, potentially contributing to longer-term PAH exposures post-wildfire. To understand the abundance, retention and chemistry of PAHs on interior indoor surfaces (glass, drywall), a sampling and extraction method is developed using solvent-soaked wipes followed by sonication and gas chromatography – mass spectrometry analysis. We modified the method to recover PAHs from HVAC filters by directly extracting a section of a filter (i.e. no solvent wipe). Total and extraction recovery rates were estimated by doping the surfaces with a known quantity of a mixture of 16 PAHs. Extraction recovery rates ranged from 7 to 86 %. Total recovery rates, that include sampling and extraction processes, ranged from 0.1 to 77 % for glass, and from 0.7 to 37 % for painted drywall. Across tested materials, we observed low recovery rates for low molecular weight PAHs and higher recoveries for high molecular weight PAHs. Recovery rates were consistently low for painted drywall, suggesting PAHs are retained, perhaps due to the porosity of the paint. In contrast, we find consistently higher recoveries from HVAC filters, another porous material, likely due to sonication of the material without need for solvent wipe. Ongoing studies will expose materials to simulated woodsmoke and estimate retention of PAHs under natural attention and various cleaning conditions.