Prodigious Amounts of Hydrogen Oxides Generated by Corona Discharges on Tree Leaves

Prodigious amounts of the hydroxyl radical (OH) are generated in the laboratory on tree leaves by corona discharges, which also occur on trees during thunderstorms. Production rates of OH and HO₂ depend on the applied electric field generating the corona discharge, leaf dryness, and the presence of liquid water on the leaf. However, they are independent of leaf type and corona discharge polarity for a given corona ultraviolet (UV) flux. Production rates of OH, HO₂, and O₃ strongly correlate with corona UV flux. Although the contribution of corona-produced OH to total global OH production is unlikely to be important, corona-generated OH is likely a few orders of magnitude greater than oxidation by known processes in the vicinity of the affected leaves, potentially influencing atmospheric oxidation and tree and forest ecology.