Evidence for the production of hydrogen peroxide in rainwater by lightning during thunderstorms

Abstract

Rain samples were collected sequentially from individual events at a site in Miami, Florida, USA, from April 1995 to October 1996, and analyzed for H2O2, major anions, pH, temperature, and rainfall amounts. The measurements showed that in the absence of lightning, the concentration of H2O2, like that of sulfate and other conservative constituents, 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 removal of atmospheric H2O2. However, during the course of several thunderstorms, H2O2 concentration increased significantly with time, whereas the concentration of sulfate and other conservative constituents remained fairly constant or decreased as a function of time. These observations indicate that substantial amounts of H2O2 in rainwater were produced by lightning activities during thunderstorms. Possible mechanisms are proposed here.