American Association for Aerosol Research - Abstract Submission

AAAR 39th Annual Conference
October 18 - October 22, 2021

Virtual Conference

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Quantifying Emission Factors from Mixed Conifer Forest Controlled Burns Aimed to Reduce Wildfire Risk at Blodgett Forest Research Station California

DEEP SENGUPTA, Nathan Kreisberg, Coty Jen, Yutong Liang, James D.A. Butler, Rebecca A. Sugrue, Robert Weber, Paul Van Rooy, Afsara Tasnia, Emre Ozen, Edward Gonzalez, Jason Kriesel, Kevin K. Schwarm, Mitchell R. Spearrin, Thomas W. Kirchstetter, Robert York, Daniel Foster, John Battles, Scott Stephens, Kelley Barsanti, Allen Goldstein, University of California, Berkeley

     Abstract Number: 471
     Working Group: Wildfire Aerosols

Abstract
Climate change and prolonged fire suppression strategies in California have led to an increase in the frequency and severity of large wildfire events in recent years. The particulate matter (PM) concentrations across the western United States have increased broadly following these events, impacting air quality and human health over large areas. In order to reduce wildfire risks, California is increasing application of controlled or prescribed burning to reduce accumulated fuels that could otherwise be conducive to wildfires. Extensive field and laboratory studies have been conducted to develop emission profiles from wildfires, but emission factors from prescribed burns under realistic conditions have been less widely studied.

We present emissions profiles from prescribed burns of managed and unmanaged land located in a mixed conifer forest of California conducted in 2017 and 2021. In Fall 2017, we measured emissions factors/profiles of gaseous species (carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx)) and PM characteristics from filter-based measurements mounted on an All-Terrain Vehicle platform. PM samples were analyzed for total elemental (EC) and organic carbon (OC) using thermal-optical method and organic compounds (using two-dimensional gas chromatography mass spectrometry method). We were able to distinguish the emissions between active and smoldering phase of burning and between managed and unmanaged forest plots. In order to capture the variability of emissions in smoke plume we developed a drone-based sensor platform that includes real-time sampling of CO, CO2, NOx, black carbon and collection of sorbent tubes for volatile organic compounds and filter samples for PM2.5 to be analyzed for organic compounds, OC, and EC. The drone was deployed for a set of four burns in spring 2021. We observed the evolution of smoke plumes during flaming and smoldering combustion phases and associate them with temperature profiles from thermal imageries, and computed modified combustion efficiencies using the drone sensor package. The resulting data will provide emission profiles and emission factors for prescribed burns to improve the FOFEM model of emissions used by the California Air Resources Board for air quality modeling.