Peroxides occur in atmospheric rain, fog and snow samples in concentrations as high as several hundred micromolar. In addition to its deleterious effects on human health and plant growth, hydrogen peroxide is generally believed to be the principal oxidant for sulfur dioxide in the Northeastern United States, resulting in enhanced acidity of cloudwater. Recent work has shown that organic peroxides oxidize sulfur dioxide at rates comparable to that of hydrogen peroxide, and some field measurements suggest that organic and hydrogen peroxides may occur in the atmosphere in similar concentrations. In spite of their importance, we are not certain what fraction of total atmospheric peroxides are organic, nor do we have a complete understanding of the processes which produce and destroy them. This grant supports laboratory and field studies aimed at a better understanding of peroxide occurrence and chemistry. Using a newly developed technique, we will analyze precipitation samples for organic and hydrogen peroxide.
