HR: 0800h
AN: A21C-0868    [Abstracts]
TI: Formation of Singlet Molecular Oxygen on Illuminated Ice and Snow
AU: * McKellar, S R
EM: srmckellar@ucdavis.edu
AF: Department of Land, Air, and Water Resources, University of California, Davis, One Shields Ave., Davis, CA 95616 United States
AU: Anastasio, C
EM: canastasio@ucdavis.edu
AF: Department of Land, Air, and Water Resources, University of California, Davis, One Shields Ave., Davis, CA 95616 United States
AB: Pollutants and other trace compounds on snow and ice are transformed both by direct photolysis as well as indirect photoreactions mediated by oxidants such as hydroxyl radical (OH). These reactions likely play a major role in the fate of environmental contaminants in regions with permanent or seasonal snow cover, but we know relatively little about which reactions are important and at what rates they transform trace pollutants. The indirect photodegradation of organics is most likely caused by oxidants such as OH and singlet molecular oxygen (1O2* ), which can be formed in the snowpack by illumination from the sun. While some recent work has characterized the formation of OH in snow, the presence of 1O2* on illuminated snow or ice has not been studied previously. In this study, our goal is to determine the steady state concentrations of singlet molecular oxygen in illuminated snow samples collected from Summit, Greenland during the summer of 2005. We add furfuryl alcohol (FFA), which acts as a chemical probe of singlet molecular oxygen, to ice pellets made from Greenland snow samples and monitor the rate of loss of FFA during illumination. Our initial results indicate that 1O2* is formed in illuminated Summit samples and that the steady-state concentration of 1O2* is much larger on ice (-10 °C) than in liquid solution (°C) using the same prepared sample. We will present our measured steady-state concentrations of 1O2* as well as the impacts of this oxidant on the lifetimes of trace organics such as PAHs and biogenic phenols in Greenland snow.
DE: 0471 Oxidation/reduction reactions (4851)
DE: 0736 Snow (1827, 1863)
DE: 0738 Ice (1863)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005