A234-01
Chemical Aging of Biomass Burning Organic Aerosol: Insight from Fast Near-Molecular Measurements

Wednesday, 16 December 2020: 07:00
Virtual
Demetrios Pagonis1, Pedro Campuzano-Jost1, Hongyu Guo2, Doug A Day1, Melinda Schueneman1, Benjamin A Nault1, Wyatt Brown1, Alexander Laskin3, Kyla S.A. Siemens3, Matthew Mitchell Coggon4,5, Joshua P DiGangi6, Glenn S Diskin7, Marta A Fenn6, Georgios Gkatzelis8,9, Johnathan W Hair6,10, Hannah S Halliday6,11, Joseph M Katich4,12, John B Nowak6, Anne Elizabeth Perring13, Pablo E Saide14, Kanako Sekimoto15, Taylor J Shingler6,16, Laura Thapa14, Carsten Warneke17 and Jose L Jimenez1, (1)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Chemistry, Boulder, CO, United States, (2)University of Colorado Boulder, Boulder, CO, United States, (3)Purdue University, Department of Chemistry, West Lafayette, IN, United States, (4)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (5)NOAA Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO, United States, (6)NASA Langley Research Center, Hampton, VA, United States, (7)NASA Langley Research Ctr, Hampton, VA, United States, (8)Cooperative Institute for Research in Environmental Sciences, Boulder, United States, (9)NOAA Earth Systems Research Laboratory, Chemical Sciences Division, Boulder, United States, (10)NASA Langley, Hampton, VA, United States, (11)US Environmental Protection Agency Research Triangle Park, Durham, NC, United States, (12)NOAA Chemical Sciences Laboratory, / CIRES, Boulder, CO, United States, (13)Colgate University, Department of Chemistry, Hamilton, NY, United States, (14)University of California Los Angeles, Atmospheric and Oceanic Sciences, Los Angeles, CA, United States, (15)Yokohama CIty University, Graduate School of Nanobioscience, Yokohama, Japan, (16)Science Systems and Applications, Inc., Hampton, VA, United States, (17)CIRES and NOAA ESRL, Chemical Sciences Laboratory, Boulder, CO, United States
Recorded Presentation
Abstract:
The chemical composition of biomass burning organic aerosol (OA) evolves rapidly as it is transported downwind of a fire. Changes in composition are driven by dilution, evaporation, and secondary OA (SOA) production. Here we present airborne OA measurements from an extractive electrospray mass spectrometer (EESI) and an Aerodyne high-resolution Aerosol Mass Spectrometer (AMS) during FIREX-AQ. By combining the bulk OA composition measured by AMS with speciated OA composition measured by EESI, we quantify the relative contributions of SOA production and primary OA (POA) evaporation to the evolution of OA composition downwind of wildland fires. Evaporation rates of bulk OA and levoglucosan (a component of POA) are quantified through a combination of thermodenuder measurements and sampling smoke plumes at varying ambient temperatures. Rates of SOA production are quantified through measurements of individual SOA components by EESI, and through positive matrix factorization of AMS spectra. We observe SOA production rates exceeding 100 μg sm-3 h-1 (standard conditions 273 K, 1013 mbar) and simultaneously measure evaporation of POA components, with minimal change in dilution-corrected OA concentration; this provides direct evidence for balance in SOA production and POA evaporation rates in near-field aging of biomass burning OA. Lastly, we use measurements of day-old smoke and results from a chemical box model to evaluate the impact of these processes on OA concentrations further downwind of fires.
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