What Makes The Air Smell So Good After a Rain?

By kncitom on October 4, 2018
photo by: Tom “I Hate Getty Images” Mailey

That fresh smell after the first rain in a long time is one of the best ever. But have you ever wondered where it comes from?

Turns out, actual scientists have.

According to a report in Smithsonian.com, research shows the smell comes from, basically, three things: plant oils, bacterial spores, and ozone.

Plant oils well up during dry periods, and when hit by raindrops, the oils–which can be on leaves, in bark, or dripped onto the ground–release pleasant-smelling compounds.

In forested areas, there is a bacteria that produces a compound called geosmin. Geosmin is a byproduct of spore production from this bacteria, and when geosmin is hit by rain, it’s musky chemicals are released into the air and, eventually, our nostrils.

And the third source of that awesome smell believe it or not is ozone–especially if the storm that moved through had lightning.  The electrical charge from lightning can split oxygen and nitrogren molecules and when that happens, they can re-combine to form nitric oxide which then combines with other chemicals in the…uh…oh, never mind. Just…trust me. The third thing is ozone.

Anyway, who cares, really, where the smell comes from…as long as we get to enjoy it, am I right? Am I right?!

Like Pat did yesterday in his El Dorado Hills backyard…

If you really wanna understand the whole process of sweet-smelling air after the first rain in awhile, that Smithsonian article does a much better job than I do of explaining it. Click here




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