Chemical Composition of Fire Smoke-Emitted Organics in the Gas and Aerosol Phase During the Recent G-WISE-2 Prescribed Burn Experiments
VIGNESH VASUDEVAN GEETHA, Lee Tiszenkel, Rawad Saleh, Joseph O'Brien, Shanhu Lee, University of Alabama Huntsville
Abstract Number: 187
Working Group: Aerosol Chemistry
Abstract
Forest fires are emerging and significant air pollutant sources, but it is currently poorly understood how oxygenated organics generated from fires vary with different fuel and burn conditions. Prescribed fires are designed to mitigate the intense wildfires to reduce the widespread fire exposures to the environment and human beings. In this study, we will present the chemical compositions of the oxygenated organics, a major SOA precursor, in the gas and aerosol phase emitted from the burn experiments during the recent G-WISE-2 (Georgia Wildland fire Simulation Experiment) campaign conducted in the forest fire lab in the University of Georgia. Burn experiments to simulate prescribed fire activities were carried out using fuel beds reconstructed from surface fuels resembling forest floors in the Southeastern United States. The fuel beds (fine, woody, and duff) are burned under different conditions of moisture, relative humidity, duff content, and burn conditions (flaming or smoldering) specific within the typical prescription window. Using an online FIGAERO-HrTOF-CIMS (filter inlet for gas and aerosol coupled with high-resolution time-of-flight chemical ionization mass spectrometer) with iodide reagent and offline LC-ESI Orbitrap MS (liquid chromatography-electrospray ionization Orbitrap mass spectrometer), we characterized and quantified the oxygenated organics emitted from the burns under the different controlled conditions. In this presentation, we will discuss the effects of external factors such as fuel bed composition, fuel moisture content, wind speed, and burn intensity on overall oxygenated organic molecule (OOMs) composition and volatility distribution in the fresh and aged aerosols to understand the chemical processes involved in their formation and evolution in the smoke plume.