AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Optical, Physical, and Chemical Properties of Emissions from Open Combustion of Cheatgrass (Bromus Tectorum)
MEGAN RENNIE, Vera Samburova, Deep Sengupta, Andrey Khlystov, Hans Moosmuller, Desert Research Institute
Abstract Number: 609 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract Cheatgrass (Bromus tectorum) is a non-native, invasive annual grass species in the U.S. Intermountain West (USIMW) that plays an important role in fire ecology. Its increasing presence has created higher fuel loads that greatly amplify the frequency and extent of rangeland fires. Open areas where shrubs and desert grasses were once separated by areas of open soil are now connected through cheatgrass growth. Many studies have been conducted on the ecological effects of cheatgrass as an invasive species in the USIMW, yet next to nothing is known about optical, physical, and chemical properties of emissions from cheatgrass fires as needed for better estimating radiative forcing and understanding health effects. Cheatgrass burns primarily in the flaming combustion phase where large amounts of black carbon aerosols are emitted. These emissions contribute to air pollution events, affect the radiative budget and climate change, and can cause severe health effects. Laboratory open combustion of cheatgrass was performed in the biomass combustion chambers of the Desert Research Institute to determine fuel-based emission factors and the physical and chemical properties characterizing the emissions of black carbon and other combustion aerosols. Our research also characterizes the physical properties of the emitted aerosols including size distribution, shape, and morphology as needed for a process-based understanding of particle optics, transport, and deposition. Additionally, the chemical composition of emitted aerosols will be determined as needed for a better understanding of the physical properties and toxicology that affect health impacts. These measurements will be analyzed to provide data essential for the modeling of radiative forcing and health impacts of cheatgrass fire emissions.