Ozone

[micky]

When I was a little boy and the sparking from my Lionel train included a smell, someone told me that was ozone. That's true, right?

[T]

Yes, electric sparks create ozone. Smells a bit like chlorine.

[Frank]

Same after an electrical storm. Ozone is a potent oxidizing agent not often used in the lab. Some use it to get rid of house odors but it can bleach contents like carpet and drapes.