HR: 15:10h
AN: A53E-07    [Abstracts]
TI: Uptake of aldehydes by sulfuric acid aerosols through acid-catalyzed reactions
AU: * Garland, R M
EM: rebecca.garland@colorado.edu
AF: Cooperative Institute for Research in the Environmental Sciences, University of Colorado UCB 216 , Boulder, CO 80309
AU: * Garland, R M
EM: rebecca.garland@colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO 80309
AU: Beaver, M R
EM: melinda.beaver@colorado.edu
AF: Cooperative Institute for Research in the Environmental Sciences, University of Colorado UCB 216 , Boulder, CO 80309
AU: Beaver, M R
EM: melinda.beaver@colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO 80309
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: Cooperative Institute for Research in the Environmental Sciences, University of Colorado UCB 216 , Boulder, CO 80309
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO 80309
AU: Elrod, M J
EM: matthew.elrod@oberlin.edu
AF: Department of Chemistry, Oberlin College, Oberlin, OH 44074
AU: Tolbert, M A
EM: margaret.tolbert@colorado.edu
AF: Cooperative Institute for Research in the Environmental Sciences, University of Colorado UCB 216 , Boulder, CO 80309
AU: Tolbert, M A
EM: margaret.tolbert@colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO 80309
AB: Atmospheric aerosols are complex mixtures of organic and inorganic compounds. While it is well understood how inorganic species form aerosols, the incorporation of organic material into atmospheric aerosols can occur by many different avenues, many of which are not well understood. In this study, we use an Aerodyne Aerosol Mass Spectrometer (AMS) and FTIR spectroscopy to probe the uptake of gas phase aldehydes by sulfuric acid and ammonium sulfate aerosols. Preliminary studies have focused on the uptake and reaction of hexanal with ammonium sulfate and sulfuric acid. Inorganic aerosols are produced via atomization and then combined with a flow of hexanal in a mixing cell. Additional mixing cells are added in order to vary residence time. The flow is then directed into either the FTIR flow tubes or the AMS for analysis. For ammonium sulfate aerosols that were exposed to hexanal vapor, no organics were observed to partition into the particle phase using either the FTIR or AMS. Pure hexanal also did not condense to form organic particles. In contrast, particulate organics were readily observed in the AMS when the same pressure of hexanal was exposed to sulfuric acid particles with a composition of 75 wt% sulfuric acid. The mass spectra for hexanal/sulfuric acid particles showed many peaks above m/z of 100 (that of hexanal) suggesting that acid-catalyzed reactions took place. In addition, the sulfuric acid particles showed substantial growth in the time of flight spectrum of the AMS when exposed to hexanal. Ongoing studies will probe the reaction as a function of residence time, sulfuric acid concentration, aldehyde composition and aldehyde concentration.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution--urban and regional (0305)
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting