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

Atmospheric electrical discharges have been linked to the production of oxidants like hydroxyl radicals. Thunderstorm anvils are known to generate large amounts of OH. However, the role of other types of discharges, such as corona on grounded metal objects, in oxidant production remains unclear. Prior research has shown that electrical discharges can influence air chemistry. Yet, the extent to which corona discharges contribute to oxidant levels is not fully understood. This gap motivated the investigation into whether corona discharges on grounded metal objects also produce significant oxidants. The study aimed to explore the potential of such discharges to generate OH and related species. Field measurements and laboratory experiments were used to address this question. The findings could help refine models of atmospheric chemistry and air quality. The study's contribution lies in identifying a new source of oxidants in the atmosphere.

This study aimed to determine whether corona discharges on grounded metal objects during thunderstorms generate large amounts of oxidants. The specific problem addressed is the lack of understanding about the oxidant-producing potential of such discharges. The motivation stems from the need to better characterize atmospheric oxidant sources. Thunderstorms are known to produce OH in anvils, but other discharges remain understudied. The researchers sought to measure OH, HO2, and O3 during thunderstorms in Houston. They also aimed to understand how corona discharges influence oxidant levels. The study combined field measurements with laboratory experiments to validate findings. The goal was to assess the significance of corona discharges in atmospheric oxidant production.

The study combined field measurements and laboratory experiments to investigate corona discharge effects. Field data was collected during seven thunderstorms in Houston, TX, in summer 2006. OH, HO2, and O3 concentrations were measured using an inlet system on a rooftop site. The researchers analyzed these field results alongside controlled laboratory experiments. In the lab, electric fields were varied to simulate corona discharges. The setup allowed for measuring OH, HO2, and O3 production under controlled conditions. The inlet of the OH-measuring instrument was used to generate corona in the lab. The experiments demonstrated that higher electric fields increased oxidant production. The combination of field and lab data provided evidence of corona's role in oxidant generation.

Field measurements revealed OH and HO2 concentrations ranging from hundreds of parts per trillion to parts per billion during thunderstorms. These values were significantly higher than ambient levels. Laboratory experiments showed that corona discharges on the inlet produced OH, HO2, and O3. The study found that increasing the electric field increased oxidant production. Ozone levels were 14 times higher than OH and HO2, which were equal. Calculations suggested that corona on lightning rods could generate OH at 10–100 times ambient levels. At high-voltage power lines, OH levels could reach 500 times ambient a meter away. The findings suggest that corona discharges on grounded metal objects are a significant oxidant source.

The authors suggest that corona discharges on grounded metal objects during thunderstorms generate extreme amounts of OH, HO2, and O3. Field and laboratory evidence supports this conclusion. The study shows that corona discharges on inlets and lightning rods produce significant oxidants. The findings challenge the assumption that UV radiation is the main cause of polymer insulator degradation. Instead, the authors propose that corona-generated OH is likely the primary initiator. The study highlights the importance of considering corona discharges in atmospheric chemistry models. The data suggests that these discharges can elevate oxidant levels far beyond ambient concentrations. The results may improve understanding of air quality and material degradation processes.