Bromine (Br) and Sulfur Dioxide (SO2) Heterogeneous Chemistry on Ice and Organic Acids at Tropospheric Temperatures

Health Research Incorporated/New York State Department Of Health, Menands NY

Investigators

Abstract

This project involves laboratory studies designed to help elucidate the mechanism of heterogeneous bromine and chlorine activation on ice surfaces. Halogen chemistry is implicated in the destruction of boundary layer ozone at high northern latitudes in spring. Proposed mechanisms in the literature involve halogen chemistry, but require processes to maintain halogens in their active forms. This work investigates the heterogeneous reactions of hypohalous acids (HOBr and HOCl) with hydrohalic acids (HBr and HCl) on ice, and the role of sulfur dioxide and dicarboxylic acids present on the ice surface. The reaction probabilities will be investigated as functions of sulfur dioxide pressure, temperature and acidity. This work will improve understanding not only of the details of boundary layer ozone loss, but will also be relevant to understanding the fate of atmospheric sulfur dioxide and the stability of dicarboxylic acids in ice cores. In addition to contributing to understanding in the area of boundary ozone loss chemistry, and gas-surface interaction phenomena, this project will involve training of undergraduate, graduate, and post-doctoral students in laboratory methods for studying heterogeneous reactions.