During thunderstorms, leaves from trees and other plants create mini electric discharges that can significantly alter the surrounding air quality. But researchers are unsure if this is beneficial or harmful.
When lightning flashes above, plants on the ground may respond in kind.
According to a recent study, trees’ electric discharges on their sharp, pointy leaves cause thunderstorms to have an impact on the quality of the air around them.
On tree leaves, weak electrical discharges known as corona can happen when thunderstorms rumble overhead.
A recent study led by a group of Penn State scientists found coronas produce significant quantities of atmospheric chemicals that may have an impact on the quality of the air near forests.
Jena Jenkins, a postdoctoral scholar from Penn State’s Department of Meteorology and Atmospheric Science, said that while little is known about how widespread these discharges are, her group estimated that the coronas produced on trees during thunderstorms may have a significant effect on the surrounding atmosphere.
Coronas and Pointy Sharp Leaves.
According to scientists,When thunderstorms hit, this bizarre electrical discharge, called a corona, forms on tree leaves. Researchers at PennState University have yet to conduct an in-depth study on this phenomenon, although they estimate that coronas generated on trees under thunderstorms could have a large impact on the surrounding air.
Why? Well, coronas product extreme amounts of the hydroxyl radical and the hydroperoxyl radical, the latter of which initiates important chemical reactions in the atmosphere that clean the air of greenhouse gases like methane while also producing ozone as well as aerosol particle pollution. Since the hydroxyl radical reacts with hydrocarbons naturally emitted by leaves to produce ozone and particulate matter, these spikes could impact air quality.
“There are about two trillion trees in areas where thunderstorms are most likely to occur globally and there are 1,800 thunderstorms going on at any given time. This is definitely a process that’s going on all the time and based on the calculations we’ve been able to do so far, we think this can affect air quality in and around forests and trees,” said Jena Jenkins, a postdoctoral scholar in the Department of Meteorology and Atmospheric Science at Penn State”
Accordign to 8 Billion Trees, there are approximately two trillion trees worldwide in regions where thunderstorms occur most often, and there are 1,800 thunderstorms active at any given moment.
The group discovered that coronas produce enormous quantities of hydroxyl (OH) and hydroperoxyl (HO2) radicals. The scientists explained that the hydroxyl radical starts vital chemical processes in the atmosphere that produce ozone as well as aerosol particle pollution while purging the air of greenhouse gases (GHG) like methane.
OH Levels and Air Quality.
In their research published in the Journal of Geophysical Research: Atmospheres, the scientists reported that around trees, corona-generated OH may ramp up during thunderstorms by about 100 up to 1,000 times the average levels.
The scientists pointed out that these increases in OH levels may affect air quality because OH reacts with hydrocarbons that are naturally released by leaves to generate particulate matter and ozone.
Willian Brune, a distinguished professor of meteorology from Penn State, explained that the hydroxyl radical helps to oxidize many pollutants in the atmosphere, including methane, a GHG, which enhances air quality and slows climate change.
Eight Species, Wet Leaves, and UV Radiation.
The research expands on a prior study led by Brune that discovered lightning as well as subvisible discharges in thunderstorm storm clouds are potentially important sources of global OH, contributing up to 2 to 16% of the OH chemistry of the planet’s atmosphere.
Jenkins said that they observed huge quantities of this hydroxy radical being produced, despite the corona’s charge being weaker compared to the lightning and sparks they had previously observed.
Eight different tree species’ leaves were tested in the lab under a variety of conditions, including being wet to simulate rain, by the scientists.
The amount of OH and HO2 produced by corona discharges across all tree species and the amount of UV radiation generated by the discharges was found to be strongly correlated.