Several research lines have suggested that lightning during thunderstorms could produce significant amount of hydrogen peroxide (H2O2) in rainwater. To confirm this hypothesis and estimate the possible source strength, a study was made of the varations in the concentrations of H2O2 and other consitituents of rainfall during the course of individual thunder- and nonthunder-storms in Miami, Florida from the spring of 1995 to the fall of 1996. The obtained data showed that temporal variation in the concentration of H2O2 during thunderstorms is very different from that during nonthunder- storms, while temporal variations in the concentration of conservative constituents, such as sulfate ion, are quite similar during thunderstorms and nonthunderstorms. In the absence of lightning, the concentration of H2O2 either remained fairly constant or decreased as a function of time during the storms depending on whether rainout or washout process was the dominant pathway for the transport of atmospheric H2O2 onto the earth's surface; However, during the course of several thunderstorms, the concentration of H2O2 significantly increased with time. A H2O2 concentration up to 3.9 x 10-5 M was observed during a summer thunderstorm. The data indicates that electrical storm activity could produce substantial amount of H2O2 in rainwater. The possible mechanisms involved in the lightning-induced production of H2O2 during thunderstorms will be discussed in this presentation
Symposium on Interdisciplinary Issues in Atmospheric Chemistry