AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Chemical Composition of Biomass Burning Particles Measured with a Soot Particle Aerosol Mass Spectrometer Downwind during the BBOP Study
TIMOTHY ONASCH, John Shilling, Arthur J. Sedlacek, Edward Fortner, Mikhail Pekour, Shan Zhou, Sonya Collier, Qi Zhang, Andrew Freedman, Leah Williams, Lawrence Kleinman, Aerodyne Research, Inc.
Abstract Number: 528 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract The Biomass Burning Observation Project (BBOP), a Department of Energy (DOE) sponsored study, measured emissions from wildland fires in the Pacific Northwest and agricultural burns in the Central Southeastern US from the DOE Gulfstream-1 airborne platform over a four month period in 2013. Rapid physical, chemical and optical changes in biomass burning particles were measured downwind (< 3 hours temporally) from wildland fires. The chemical composition of the particulate emissions was characterized using an Aerodyne Soot Particle Aerosol Mass Spectrometer (SP-AMS) and will be presented in the context of the fire location, combustion conditions, and optical property measurements, including extinction and single scattering albedos.
Chemical signatures reflect different combustion conditions within a given fire plume, indicating a high diversity within a given burn. The non-refractory chemical composition, including the level of oxidation (i.e., O:C, H:C, and organic mass/organic carbon ratios, OM:OC) changed systematically during the hours of atmospheric transport measured during BBOP. The oxidation of the organic compounds increases with downwind advection, while the primary markers, such as m/z 60, decrease. These chemical changes appear to continue downwind, when compared with additional further downwind measurements, even as the ratio of organic mass to carbon monoxide appears to remain constant. We will also discuss the chemistry in light of observations of tar ball formation and evolution.