AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Chemical and Optical Properties of Biomass Burning Aerosol
ROYA BAHREINI, Joshua P. Schwarz, Anne Perring, Daniel Lack, Justin Langridge, Francesco Canonaco, Andre Prévôt, John Holloway, Carsten Warneke, Jessica Gilman, Brian Lerner, Joost de Gouw, Ann Middlebrook, University of California, Riverside
Abstract Number: 78 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Biomass burning (BB) is a large source of organic and inorganic species in both the gaseous and condensed phase. Toxicity of some of the BB components is an air quality concern in areas downwind of the fires. In addition, emissions of primary or secondary light absorbing species (black carbon (BC) or brown carbon (BrC)) may have regional and global climate impacts. Here we present results from fresh (Schultz Fire, AZ and 4-Mile Fire, CO) vs. long-range transported (ARCPAC field study) biomass burning emissions, sampled by an aerosol mass spectrometer (C-ToF-AMS) and a single particle soot photometer (SP2) for aerosol chemical characterization and by a cavity ring-down spectrometer (CRDS), a photoacoustic spectrometer (PAS), and/or a particle soot absorption photometer (PSAP) for aerosol optical characterization. Auxiliary gas phase measurements are also available for overall characterization of the air masses. We perform factor analysis on the organic aerosol (OA) mass spectra to determine the contribution of biomass-burning organic aerosol (BBOA) in the different fires and examine relations between BBOA and other tracers in the OA spectra with the optical measurements. Our analysis of the fresh BB emissions in the 4-Mile Fire indicates that there is a linear relationship between the mass absorption efficiency (MAE) of OA at 404 nm and the ratio of levoglucosan-related fragment (m/z 60) to oxidized OA fragment in the AMS (m/z 44) [Lack et al., ACP, 2013], indicating contribution of BB-related compounds in the condensed phase to BrC. Results from the factor analysis and optical measurements indicate that MAE of OA approached 1.6 m2/g in the most intense BB plumes, i.e., periods when BBOA mass fraction was ~1. We will expand our analysis of the 4-Mile Fire and extend it to the other datasets indicated above in order to link BB aerosol chemistry with climate impacts of BrC in biomass burning.