AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Aging of Biomass Burning Aerosols: Comparison of Smog Chamber Experiments with Ambient Aerosols
JEFFREY L. COLLETT, Yury Desyaterik, Amy P. Sullivan, Christopher Hennigan, Allen Robinson, Amanda Holden, Sonia Kreidenweis, Bret Schichtel, Colorado State University
Abstract Number: 443 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Knowledge of the chemical composition of atmospheric organic aerosols (OA) is essential for accurate representation of OA in air quality and climate models. On the global scale, biomass burning (BB) emissions could account for more than 50% of the total burden of organic aerosols (Reddy et al., 2004). Recent smog chamber studies have shown that the mass of the BB aerosol can increase more than two-fold, for some fuels, due to photooxidation (Hennigan et al., 2011). Through a series of laboratory experiments, we are working to quantify changes in the chemical composition of biomass smoke particles as a result of photochemical aging. One specific objective of this study is to identify markers for biomass burning SOA and test whether these markers can be used in atmospheric samples to quantify SOA formation from aging of biomass burning emissions.
In a series of experiments, biomass burning smoke was aged by photooxidation in a smog chamber. In order to initiate photochemistry, the chamber was irradiated with UV light. Filter collected aerosol samples were extracted with DI water, and analyzed with Time-of-Flight Electrospray Ionization Mass Spectrometry. Mass spectra of secondary organic aerosol formed in the aging experiments include important contributions from organic nitrates (nitrophenol, nitrocresol, nitrocatechol, and nitroguaiacol) and aromatic acids (benzoic acid, mono and di-hydroxybenzoic acid). Both the nitrates and acids are most likely formed due to the oxidation of the lignin decomposition products (guaiacol and syringol derivatives) by reaction with OH and NO2. The results of chamber experiments will be compared with ambient aerosol samples known to be affected by biomass burning.
Reddy, M.S., & Boucher, O. Journal of Geophysical Research, 109, D14202, 2004.
Hennigan, C.J., et al. Atmos. Chem. Phys., 11, 7669–7686, 2011.