When lightning Lightning above, plants on the ground can react in the same way.
Scientists have long known that plants and trees can emit small, visible electrical discharges from the tips of their leaves when the plants are trapped under the electric fields generated by overhead thunderstorms. These discharges, known as corona, are sometimes visible as faint, blue sparks that glow around charged objects.
Now, new research suggests these plant sparks could be altering the environment air quality in a way never before recognized. But whether the effects of these mini-shocks in the atmosphere are positive or negative remains unclear.
In the study, published August 9 in the Journal of Geophysical Research: Atmospheresthe researchers recreated the electric fields of thunderstorms in a laboratory and analyzed the coronas emitted by eight plant species under different conditions.
The results showed that all coronas produced large amounts of radicals – chemicals containing unpaired electrons that are highly reactive with other compounds – that can significantly alter the quality of the surrounding air.
“Although little is known about how widespread these discharges are, we estimate that coronas produced on trees during thunderstorms could have a significant impact on the surrounding air,” the study’s lead author explains jen jenkinan atmospheric scientist at Penn State University said in a expression.
The two radicals given off by the plant corona are hydroxyl (OH) and hydroperoxyl (HO).2), both of which are negatively charged and are known to oxidize or steal electrons from a number of different chemical compounds, thereby converting them into other molecules.
The researchers were particularly interested in the concentrations of hydroxyl radicals, as these have a greater impact on air quality.
“The hydroxyl radical contributes to the overall atmospheric oxidation of many air pollutants,” study co-author William Brunea meteorologist at Penn State University said in the statement.
But if the same radical reacts with oxygen, it can be formed ozone, which, despite playing an important role in the upper atmosphere, is toxic to humans. The radicals can also create aerosol particles that affect air quality, he added.
This isn’t the first time researchers have shown the connection between thunderstorms and hydroxyl radicals.
In 2021, a research team led by Brune found that lightning is an important precursor of hydroxyl radicals in the atmosphere. In her work, published in the journal Sciencethe team theorized that thunderstorms could be directly responsible for up to a sixth of the hydroxyl radicals in the atmosphere.
In September, another team led by Brune published a follow-up study that was published in the journal Earth, atmospheric and planetary sciencesWithwhich showed that coronas produced by metallic objects such as telephone poles and transmission towers produce slightly higher levels of hydroxyl radicals than plant coronas.
However, the amounts of radicals produced by plants and artificial corona are significantly lower than those produced directly by lightning.
“Although the charge generated by the [plant] When the corona was weaker than the sparks and flashes we looked at previously, we still saw extreme amounts of this hydroxy radical being produced,” Jenkins said.
Given the large number of trees present in lightning-prone areas, plant-produced corona could represent an understudied source of radicals with highly unpredictable air quality effects, she added.
“There are about two trillion trees in areas where thunderstorms are most likely in the world, and there are 1,800 thunderstorms at any given time,” Jenkins said.
For this reason, the researchers want to further study these coronas in detail to understand the impact they have on local air quality and on a global scale.
“The hydroxyl radical is the primary scavenger of the atmosphere,” Jenkins said. “So if we can better understand where this stuff is made, we can better understand what’s happening in the atmosphere.”
Other studies suggest that thunderstorms may become more frequent and stronger due to human-caused impacts climate changeso it’s important to understand how thunderstorms affect air quality, she added.
During the experiments, the team made another discovery that could help speed up this area of research: the bladed discharges gave off sharp spikes ultraviolet Radiation.
This could allow the team to indirectly study where coronas occur in the field and measure their impact on nearby air quality.