Career: Photochemical Oxidation of Dissolved Sulfur Dioxide and Other Sulfur (IV) Species in the Presence of Iron Organic Complexes in Atmospheric Waters

University Of Massachusetts, Dartmouth, North Dartmouth MA

Investigators

Abstract

Aqueous-phase oxidation of sulfur dioxide (SO2) is an important component of the atmospheric sulfur cycle. The Fe-catalyzed oxidation of dissolved SO2 by O2 in clouds is considered one of the three major pathways for the formation of sulfate, however parameterization of the Fe-catalyzed oxidation pathway in atmospheric models currently involves considerable uncertainty. This CAREER project is an investigation of the photochemical oxidation of sulfur-IV species in the presence of iron and organic compounds in atmospheric liquids. The objectives of this study are to: 1) determine the photochemical oxidation rates of sulfur-IV in both authentic atmospheric waters (e.g. rain, fog, and cloud waters) and modeled systems containing iron-organo complexes (e.g. oxalato-, glyoxalato-, and pyruvato iron complexes) 2) examine the influence of other organic pollutants (e.g. formaldehyde, acetaldehyde, formate and acetate) and transition metals (e.g. Cu and Mn) on the photooxidation of dissolved S02 in the presence of Fe-organo complexes; 3) examine the effects of dissolved SO2 on the photochemical cycling of Fe-organo complexes; and 4) evaluate the relative contribution of photochemical oxidation of sulfur-IV in the presence of Fe-organo complexes to the overall formation of sulfate in atmospheric liquid phases. The educational component of this project involves the integration of atmospheric aquatic photochemistry into a teaching program by using demonstrations, laboratory exercises, field studies, and independent research projects,