Atmos. Chem. Phys. Discuss., 12, 19277-19301, 2012
© Author(s) 2012. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
How does deposition of gas phase species affect pH at frozen salty interfaces?
S. N. Wren1 and D. J. Donaldson1,2
1Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
2Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, ON, M1C 1A4, Canada

Abstract. Chemical processes occurring on snow and ice surfaces play an important role in controlling the oxidative capacity of the overlying atmosphere. However, efforts to gain a better, mechanistic understanding of such processes are impeded by our poor understanding of the chemical nature of the air-ice interface. Here we use a surface-sensitive spectroscopic technique to investigate how the nature of the ice, whether frozen freshwater, salt water or seawater, influences pH changes at the surface. Deposition of HCl(g) leads to a very different pH response at the frozen freshwater surface than at the frozen salt water surface indicating that these two surfaces present different chemical environments. Importantly, the sea ice surface is buffered against pH changes arising from deposition of gas phase species. These results have important implications for understanding pH-sensitive processes occurring at the air-ice boundary, such as bromine activation.

Citation: Wren, S. N. and Donaldson, D. J.: How does deposition of gas phase species affect pH at frozen salty interfaces?, Atmos. Chem. Phys. Discuss., 12, 19277-19301, doi:10.5194/acpd-12-19277-2012, 2012.
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