HR: 0800h
AN: A51C-0582    [Abstracts]
TI: Halogen Activation by N2O5 Reaction on Sea Ice Surfaces
AU: * Kercher, J P
EM: kercher@atmos.washington.edu
AF: The University of Washington, Department of Atmospheric Sciences, Seattle, WA 98191, United States
AU: Thornton, J
EM: thornton@atmos.washington.edu
AF: The University of Washington, Department of Atmospheric Sciences, Seattle, WA 98191, United States
AB: The reaction of N2O5 on sea spray aerosol particles is known to release nitryl halides. Recent air mass trajectory analyses suggest ozone depletion events are correlated with air mass passage over young sea ice. To our knowledge, the reaction of N2O5 on sea ice surfaces has not yet been studied. We have examined the rate and product yields from the uptake of N2O5 on natural and artificial sea ice surfaces using a coated wall flow tube technique coupled to a chemical ionization mass spectrometer (CIMS). A wide range of halogenated species, including ClNO2, Cl, BrNO2, and Br2 and Br are promptly produced resulting in a near unity yield of gaseous halogen release. Cl containing species dominate the halogenated products, but only by a factor of 4 over Br containing products, suggesting preferential activation of Br. The product yield and reaction rates are interpreted in the context of expected sea ice and atmospheric composition for a range of polar conditions. Our findings imply that for certain conditions this chemistry may contribute substantially to polar halogen chemistry, for example, by affecting the gaseous Br/Cl radical ratio.
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting