HR: 13:55h
AN: A53E-02    [Abstracts]
TI: Size distribution and chemical composition of water soluble organic compounds in biomass burning and regional haze particles and their changes upon aging.
AU: * Rudich, Y
EM: yinon.rudich@weizmann.ac.il
AF: Department of Environmental Sciences, Weizmann Institute, Rehovot, 76100 Israel
AU: Falkovich, A
EM: alla.falkovich@weizmann.ac.il
AF: Department of Environmental Sciences, Weizmann Institute, Rehovot, 76100 Israel
AU: Schkolnik, G
EM: gal.schkolnik@weizmann.ac.il
AF: Department of Environmental Sciences, Weizmann Institute, Rehovot, 76100 Israel
AU: Graber, E
EM: ergraber@volcani.agri.gov.il
AF: Department of Environmental Sciences, Weizmann Institute, Rehovot, 76100 Israel
AU: Maenhaut, W
EM: Willy.Maenhaut@UGent.be
AF: Department of Analytical Chemistry, Institute for Nuclear Sciences, Ghent University, Proeftuinstraat 86, Gent, B900 Belgium
AU: Artaxo, P
EM: artaxo@if.usp.br
AF: Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187,, Sao Paulo, 05508 Brazil
AB: Particles from biomass burning and regional haze were sampled in Rond“nia, Brazil, during the dry (intensive biomass burning), transition and wet periods as part of the LBA/SMOCC field campaign. Water soluble species, including organic acids, inorganic ions and anhydrous sugars, in bulk and size-resolved samples were determined by ion chromatography. A new analytical method for the detection of levoglucosan, 2-methylerythritol and related compounds, based on ion chromatography, will be presented. It is shown that low molecular weight (LMW) organic acids account for a significant fraction of the water soluble organic carbon (WSOC) in biomass burning aerosols. C2-C6 dicarboxylic acids reached up to 3.7% and one-ring aromatic acids reached up to 2% of fine fraction WSOC during the burning period. The measurements suggest that low molecular weight organic acids react with excess ammonia meaning that LMW organic acids should be incorporated in thermodynamic models used to predict inorganic aerosol composition. During the burning season, most of the ionic mass correlates with K+, a known biomass burning tracer, suggesting that many of the organic acids are directly emitted by vegetation fires. The distribution of the WSOC in different aerosol sizes shifts to larger sizes as the aerosol ages and mixes with other aerosol types. Finally, this study confirms that dicarboxylic acids are mostly confined to the particulate phase, and no evidence for semi-volatile behavior was observed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting