Volatile and Semivolatile Organic Compounds in Wildfire Smoke During NOAA/NASA FIREX-AQ Campaign

Wildfires emit particulate matter and carcinogenic compounds, such as benzene, making it important to understand the potential health impacts on the surrounding communities. The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) campaign, Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ), was conducted in summer of 2019 to study wildfire composition and smoke evolution in the U.S. Air sampling was performed by Lewis-Clark State Air Chemistry Research Group as part of FIREX-AQ at various ground locations as well as larger fires. Two major wildfires studied were the Nethker Fire (~2,300 acres burned) in McCall, ID and the Williams Flats Fire (~44,450 acres burned) in Spokane, WA. Air samples were collected through thermal desorption tubes both actively (pumped air) and passively (diffusion) and then analyzed through thermal desorption gas chromatography mass spectrometry (TD/GC/MS). Benzene found in wildfire smoke was 14-134 times higher compared to background concentrations of nearby sites, depending on fire sampling conditions. Smoldering fire samples also contained higher levels of toluene, ethylbenzene, xylenes, phenol, and pinenes. These pollutants can have long and short term health effects.