Yet, that’s exactly what occurs during a thunderstorm. For the first time, scientists from the University of Maryland were able to detect lightning and its impact on air quality using high-frequency satellite observations, gaining valuable insight into how storms produce both pollution and critical chemical species that help cleanse Earth’s atmosphere.
Over the course of a few days in late June 2025, UMD Atmospheric and Oceanic Science Research Professor Kenneth Pickering and Associate Research Scientist Dale Allen used data captured by NASA’s Tropospheric Emissions: Monitoring of POllution (TEMPO) instrument to carefully monitor thunderstorms as they evolved while moving across the eastern United States. Launched in 2023, TEMPO typically tracks air pollutants across North America every hour from its perch 22,000 miles above Earth, but Pickering and Allen’s experiment allowed them to take rapid-fire measurements of the nitrogen dioxide associated with each storm at 10-minute intervals. With the instrument’s advanced capabilities, they were finally able to study complex processes as they happened in the air rather than piecing together clues after the fact.
“This is the first time this kind of research has been conducted at such a temporal frequency,” Pickering said. “Thunderstorms evolve on a rapid basis. They often build up, intensify and die within an hour’s time. These short interval observations give us better snapshots of what actually happens during a storm.”
“With this experiment, we’re able to count the number of lightning flashes as they occur using data from NOAA’s Geostationary Lightning Mapper satellite instruments, and in turn, get a more accurate idea of how much nitrogen dioxide each flash of lightning produces during a storm and how long it sticks around afterward,” Allen added. “This information will help researchers improve existing climate models and enhance our understanding of how lightning can affect the air we breathe.”
Capturing lightning in a model
When lightning strikes, it produces extremely hot temperatures that break apart nitrogen and oxygen molecules in the air. This results in the creation of nitrogen oxides, the same type of air pollutants emitted by cars or other sources of fuel combustion, which contribute to ozone pollution.
“Lightning globally makes up 10 to 15 percent of total nitrogen oxides released into the atmosphere,” Pickering said. “Human pollution is much greater, but what’s important to consider is that lightning releases nitrogen oxides at much higher altitudes, where it can be more efficient at catalyzing the production of ozone.”
While car exhaust pollutes the air near the ground, lightning pollution occurs high up in the atmosphere, where the resulting ozone is most effective for atmospheric warming. Lightning pollution and resulting ozone can sometimes be transported down to the surface, affecting air quality hundreds of miles away from the original storm. Allen noted that this effect is exacerbated in the summer, as temperatures climb higher and ozone production rates are greater.
“Lightning’s effects on climate during the summer season are comparable to anthropogenically created nitrogen oxides, which is why we wanted to study storms during June,” Allen explained.
But lightning doesn’t just create pollution—it also triggers the formation of hydroxyl radicals, important molecules that help cleanse Earth’s atmosphere by breaking down gases like methane, an important contributor to global warming and background levels of ozone. The lightning experiment provided the researchers with critical insight into this lightning-caused chain reaction, connecting the production of nitrogen oxides to hydroxyl radicals, which helped them map out the atmospheric composition and the complex molecular dynamics at play during lightning storms.
“From past studies by our group and others we believe that each flash of lightning creates about 250 moles of nitrogen oxides in the sky on average,” Allen said. However, that value is uncertain and the production by individual flashes varies by at least an order of magnitude. “We believe that when storms get more intense, lightning flashes get shorter and produce less nitrogen oxide per flash. This study will give us a chance to prove that. Understanding how the footprint of lightning will change in a world of intensifying weather extremes is essential to formulate climate models for the future.”
Decoding weather extremes and improving air quality forecasting
Pickering and Allen believe their TEMPO experiment has potential real-world impacts on daily life. Gases produced by lightning can travel on long “conveyor belts of moving air” and influence air quality far from where storms originally occurred, Allen noted. Occasionally, lightning also contributes to ground-level ozone, a primary component of smog that can trigger asthma and other respiratory issues in humans.
“For people living in mountainous areas like Colorado, this information can be very important as lightning does make a significant contribution to surface ozone at higher terrain altitudes,” Pickering said. “It could make a difference in how meteorologists predict air quality during and after storms in such regions.”
Although Pickering and Allen are still analyzing their early readings from TEMPO, they believe their experiment will help scientists evaluate how much of the polluting gases in Earth’s atmosphere can be attributed to human activities versus natural processes. Currently, atmospheric scientists are uncertain about the amount of pollution each lightning flash generates, but the TEMPO experiment provides the raw data that lays the foundation for understanding how varying degrees of lightning intensity can impact local and global air quality. The experiment also provides insight into the atmosphere’s ability to naturally break down pollutants, such as methane and other harmful hydrocarbons.
“We want to use this high-frequency data to narrow the major uncertainties in our current climate models,” Allen said. “With better data comes better predictions, and potentially better ways to protect our health and environment from both natural and human-made pollution.”
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The TEMPO mission is a collaboration between NASA and the Smithsonian Astrophysical Observatory, whose Center for Astrophysics at Harvard University oversees daily operations of the TEMPO instrument and produces data products through its Instrument Operations Center.
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