Extreme hydroxyl amounts generated by thunderstorm-induced corona on grounded metal objects

It has now been established that atmospheric electrical discharges generate unexpectedly large amounts of the atmosphere’s primary oxidant, hydroxyl (OH) in thunderstorm anvils, where lightning and weak electrical discharges are caused by atmospheric charge separation. The question is “Do other atmospheric electrical discharges also generate large amounts of oxidants?’ In this paper, we demonstrate that coronas formed on grounded metal objects produce extreme amounts of hydroxyl (OH), hydroperoxyl (HO2), and ozone (O3) when thunderstorms are overhead. Hundreds of parts per trillion (pptv) to parts per billion (ppbv) of OH and HO2 were measured during seven thunderstorms that passed over the rooftop site during an air quality study in Houston, TX in late summer 2006. A combination of the analysis of these field results and laboratory experiments show that these extreme oxidant amounts were generated by coronas on the inlet of the OH-measuring instrument and that coronas are easier to generate on lightning rods that on the inlet. In the laboratory, increasing the electric field increased OH, HO2, and O3 in negative coronas, with 14 times more O3 generated than OH and HO2, which were equal. Even with these extreme amounts of OH, it is unlikely that coronas generated on lightning rods under thunderstorms or on high voltage electrical power transmission lines produce enough OH, HO2, or O3 to be globally significant. However, local oxidation may be substantial, including oxidation of materials near the coronas.