HR: 16:15h
AN: A24B-02    [Abstracts]
TI: Estimation of Average Number of Carbons in Water Soluble Organic Compounds Present in Aerosols Inferred from Reaction with Hydroxyl Radicals
AU: * Kuroki, Y
EM: k058305@eve.u-ryukyu.ac.jp
AF: Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0213 Japan
AU: Nakama, Y
EM: k058313@eve.u-ryukyu.ac.jp
AF: Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0213 Japan
AU: Tanahara, A
EM: tanahara@lab.u-ryukyu.ac.jp
AF: Instrument Research Center, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0213 Japan
AU: Arakaki, T
EM: arakakit@sci.u-ryukyu.ac.jp
AF: Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0213 Japan
AU: Cort, A
EM: canastasio@ucdavis.edu
AF: Department of Land, Air and Water Resources, University of California, Davis, 3146 Plant & Environmental Sciences Building, Davis, CA 95616-8627 United States
AB: Many studies have been carried out to identify individual organic compounds in aerosol particles, but for many cases, only a small fraction of organic compounds was identified. We attempted to obtain overall average number of carbons in water-soluble organic compounds present in aerosol particles. We used a high volume air sampler and collected aerosol particles in Okinawa, Japan. We used an idea that hydroxyl radical reactivity with many organic compounds was at diffusion-controlled rates, having similar bimolecular rate constants. We obtained scavenging rate constants of OH radicals for water-soluble organic compounds by changing concentrations of added scavenger (i.e. benzoate). Scavenging rate constant is a sum of the product of bimolecular rate constants and concentrations of OH radical scavengers for individual compound, which are mainly organic compounds. We assumed that bimolecular rate constants for all the organic compounds are the same, then we calculated concentrations of organic compounds present in Milli-Q extract of aerosol particles. We also measured dissolved organic carbon concentrations for the same aerosol extract. By comparing the organic compound concentrations and dissolved organic carbon concentrations, we calculated average number of carbons in the organic molecules present in the aerosol particles. Results showed that the average number of carbon ranged from 1 to 8 for the samples we studied. Our results suggested that the majority of water-soluble organic compounds present in the aerosol particles collected in Okinawa, Japan consist of relatively low molecular weight organic compounds.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005