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After a rainstorm, doesn’t the world seem so clean? You might think of storms washing the earth – but they’re cleaning the air too!

There are lots of different chemicals that we humans put into the atmosphere. This includes the greenhouse gas methane. Luckily, some chemicals are good at attacking pollutants like methane, breaking them down into simpler, less damaging chemicals.

Back in 2012, NASA flew a plane through the top part of several thunderstorm clouds. The plane was packed with experiments, but one of them didn’t seem to be working properly. Scientists knew that lightning can split water to create air-cleaning chemicals such as hydroxyl (OH) and hydroperoxyl (HO2). But the experiment kept finding these chemicals, even in clouds with no visible lightning.

Recently, scientists went back to those results. They wanted to make sure that the experiment had failed, so they rigged up some tests in the lab to replicate the conditions in the clouds. Using a tesla coil, they made sparks similar to lightning flashes and got a lot of hydroxyl and hydroperoxyl gases. But when they turned the tesla coil down until it stopped sparking, they still formed lots of air-cleaning chemicals!

This result is good news for our atmosphere. While it’s no excuse for human pollution, at least storm clouds are helping with the clean-up, even if you can’t see lightning. So next time you see black clouds rolling in, you can think of the good work they’re doing!

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