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

Abstract

Atmospheric electrical discharges are now known to generate unexpectedly large amounts of the atmosphere’s primary oxidant, hydroxyl (OH), in thunderstorm anvils, where electrical discharges are caused by atmospheric charge separation. The question is “Do other electrical discharges also generate large amounts of oxidants?” In this paper, we demonstrate that corona formed on grounded metal objects under thunderstorms produce extreme amounts of OH, hydroperoxyl (HO 2 ), and ozone (O 3 ). Hundreds of parts per trillion to parts per billion of OH and HO 2 were measured during seven thunderstorms that passed over the rooftop site during an air quality study in Houston, TX in summer 2006. A combination of analysis of these field results and laboratory experiments shows that these extreme oxidant amounts were generated by corona on the inlet of the OH-measuring instrument and that corona are easier to generate on lightning rods than on the inlet. In the laboratory, increasing the electric field increased OH, HO 2 , and O 3 , with 14 times more O 3 generated than OH and HO 2 , which were equal. Calculations show that corona on lightning rods can annually generate OH that is 10–100 times ambient amounts within centimeters of the lightning rod and on high-voltage electrical power lines can generate OH that is 500 times ambient a meter away from the corona. Contrary to current thinking, previously unrecognized corona-generated OH, not corona-generated UV radiation, mostly likely initiates premature degradation of high-voltage polymer insulators.

Effect of Temperature and Water Droplets on Production of Prodigious Hydrogen Oxides by Electrical Discharges

“…Subsequent laboratory experiments confirmed that this electrically generated HO x (LHO x ) was real, that it can be generated in both sparks and weak, invisible discharges called subvisible discharges, and it has a longer lifetime than expected in spark discharges (Jenkins et al, 2021). Additional studies have demonstrated prodigious LHO x production in corona discharges (Brune et al, 2022;Jenkins et al, 2022) and LHO x has also been found to be a possibly significant source of atmospheric Abstract Recently, electrical discharges have been identified as a potentially significant source of the atmosphere's most important oxidant, the hydroxyl radical. Measurements of hydroxyl, the closely related hydroperoxyl radical, and the nitrogen oxides from sparks and subvisible discharges were made in the laboratory under different environmental and electrical conditions representing those found in the troposphere.…”

“…Subsequent laboratory experiments confirmed that this electrically generated HO x (LHO x ) was real, that it can be generated in both sparks and weak, invisible discharges called subvisible discharges, and it has a longer lifetime than expected in spark discharges (Jenkins et al., 2021). Additional studies have demonstrated prodigious LHO x production in corona discharges (Brune et al., 2022; Jenkins et al., 2022) and LHO x has also been found to be a possibly significant source of atmospheric HO x based on a global modeling study (Mao et al., 2021). Altogether, these studies have concluded that LHO x generated in thunderstorms potentially account for 0.3%–16% of global OH and LHO x generated by a variety of electrical discharge types and strengths could create 2–4 orders of magnitude more HO x locally or regionally relative to other HO x sources.…”