Volatile organic compound ratios as probes of halogen atom chemistry in the Arctic A. E. Cavender1, T. A. Biesenthal2,*, J. W. Bottenheim3, and P. B. Shepson1,2,4,5 1Department of Chemistry, Purdue University, West Lafayette, IN, USA 2Department of Chemistry, York University, Toronto, Ontario, Canada 3Science and Technology Branch, Environment Canada, Toronto, Ontario, Canada 4Department of Earth and Atmospheric Science, Purdue University, West Lafayette, IN, USA 5Purdue Climate Change Research Center, Purdue University, West Lafayette, IN, USA *now at: Sciex, Concord, Ontario, Canada
Abstract. Volatile organic compound concentration ratios can be used as indicators of
halogen chemistry that occurs during ozone depletion events in the Arctic
during spring. Here we use a combination of modeling and measurements of
[acetone]/[propanal] as an indicator of bromine chemistry, and
[isobutane]/[n-butane] and [methyl ethyl ketone]/[n-butane] are used to
study the extent of chlorine chemistry during four ozone depletion events
during the Polar Sunrise Experiment of 1995. Using a 0-D photochemistry
model in which the input of halogen atoms is controlled and varied, the
approximate ratio of [Br]/[Cl] can be estimated for each ozone depletion
event. It is concluded that there must be an additional source of propanal
(likely from the snowpack) to correctly simulate the VOC chemistry of the
Arctic, and further evidence that the ratio of Br atoms to Cl atoms can vary greatly during
ozone depletion events is presented.
Citation: Cavender, A. E., Biesenthal, T. A., Bottenheim, J. W., and Shepson, P. B.: Volatile organic compound ratios as probes of halogen atom chemistry in the Arctic, Atmos. Chem. Phys., 8, 1737-1750, doi:10.5194/acp-8-1737-2008, 2008.