Absolute concentrations of Cl and Br atoms in the Arctic troposphere near Barrow, AK as determined by halogenated volatile organic compound and alkene concentrations

HR: 11:35h
AN: A12B-05 [Abstracts]
TI: Absolute concentrations of Cl and Br atoms in the Arctic troposphere near Barrow, AK as determined by halogenated volatile organic compound and alkene concentrations
AU: * Shepson, P B
EM: pshepson@purdue.edu
AF: Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN 47907-2084 United States
AU: Keil, A
EM: keilad@purdue.edu
AF: Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN 47907-2084 United States
AU: Suciu, L
EM: ls268504@ohio.edu
AF: Department of Chemical Engineering, Ohio University, 179 Stocker Center, Athens, OH 45701 United States
AU: Gao, F
EM: fg156704@ohio.edu
AF: Department of Chemical Engineering, Ohio University, 179 Stocker Center, Athens, OH 45701 United States
AU: Young, V L
EM: valy@bobcat.ent.ohiou.edu
AF: Department of Chemical Engineering, Ohio University, 179 Stocker Center, Athens, OH 45701 United States
AU: Doskey, P V
EM: pvdoskey@anl.gov
AF: Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439-4843 United States
AB: The concentrations of several volatile organic compounds, including halogenated and olefinic species, were determined near Barrow, AK during the winter of 2005. Increasing concentrations of chloroacetaldehyde, bromoacetaldehyde, chloroacetone, and bromoacetone were attributed to reactions of ethene and propene with Br and Cl atoms in the troposphere. The measured rates of production of the halogenated species and the ambient alkene concentrations were used to calculate the absolute Br and Cl atom concentrations during periods of slight ozone depletion. Br and Cl concentrations were found to average 4±2x10⁶ molecules/cm³ and 2±1x10⁴ molecules/cm³, respectively, with values ranging from 1.3±0.3x10⁶ to 6±2x10⁶ molecules/cm³ for Br and 9±2x10³ to 4±1x10⁴ molecules/cm³ for Cl. The measurements indicate active Cl and Br chemistry in the absence of full ozone depletion in the Arctic boundary layer.
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005