Why Is the Air Especially Fresh After a Thunderstorm?

After a thunderstorm, the dust and harmful gas in the air are washed away by rain. The air becomes much cleaner and we feel the air is very fresh.

When it thunders, there is a kind of gas known as ozone which comes from oxygen. Ozone can stimulate people's nerves and make people feel excited. Besides, breathing in this kind of air also makes you feel comfortable. The resin of pine trees can also produce ozone. So when you enter a pine forest, you feel the air is very fresh, too.