HR: 0800h
AN: A51C-0083    [Abstracts]
TI: Rate Coefficients for the Reaction of OH Radical with Acetaldehyde (CH₃CHO) between 204 and 373 K
AU: * Zhu, L
EM: Lei.Zhu@noaa.gov
AF: NOAA, Aeronomy Laboratory, 325 Broadway, R/AL2, Boulder, CO 80305 United States
AU: * Zhu, L
EM: Lei.Zhu@noaa.gov
AF: The Cooperative Institute for Reaserch in Environmental Sciences, University of Colorado, CIRES, 216 UCB, Boulder, CO 80309 United States
AU: Talukdar, R K
EM: Ranajit.K.Talukdar@noaa.gov
AF: NOAA, Aeronomy Laboratory, 325 Broadway, R/AL2, Boulder, CO 80305 United States
AU: Talukdar, R K
EM: Ranajit.K.Talukdar@noaa.gov
AF: The Cooperative Institute for Reaserch in Environmental Sciences, University of Colorado, CIRES, 216 UCB, Boulder, CO 80309 United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: NOAA, Aeronomy Laboratory, 325 Broadway, R/AL2, Boulder, CO 80305 United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: The Cooperative Institute for Reaserch in Environmental Sciences, University of Colorado, CIRES, 216 UCB, Boulder, CO 80309 United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, CO 80309 United States
AB: Acetaldehyde (CH₃CHO) is one of the most abundant carbonyls in the troposphere. Oxidation of CH₃CHO by OH is an important pathway for formation of PAN, which is a significant urban pollutant and also serves as a transportable NOx reservoir in the free troposphere. Kinetics and mechanisms of the reaction of OH with CH₃CHO have been extensively studied. However, the values of the rate coefficients for this reaction under conditions of low temperatures prevalent in the upper troposphere are sparse and contradictory. Therefore, in this work, the temperature dependence of the rate coefficients for the reaction of OH with CH₃CHO was measured using pulsed laser photolytic production of OH coupled with its detection via laser induced fluorescence. The concentrations of CH₃CHO were measured precisely and accurately using FTIR spectroscopy. This analytical method also helped identify other impurities. The rate coefficients for the title reaction between 204 and 373 K will be reported and compared to previous studies; discrepancies between various reported values will be discussed. The implication of the new kinetics data to the troposphere will also be discussed.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 0399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005