FORT WAYNE, Ind. (WANE) — It’s probably one of the most notable smells, the crisp scent of the air right after the rain has passed. But, there’s a little bit of science in the air, too!

This beloved smell actually has a name: Petrichor. This word has a Greek origin to it, and it’s quite the combination of terms.

  • “Petra” – Rock or stone
  • “Ichor” – Reference to the “blood” of the immortal Greek gods

Overall, there are three components that lead to this smell that we know so well.

The first component is found in our soil. Soil-dwelling bacteria create this special substance called Geosmin. The human nose is actually super sensitive to Geosmin! As rain falls from the sky and lands on the bacteria within the soil, it bubbles up and releases a Earthy scent into the air.

The second factor is found above the soil. Our plants play a very large part in the process, especially during dry periods without any rainfall. During a dry spell, outdoor plants release an oily substance. When the rain finally returns and falls upon the plant, the water helps to release the scent within the oil. Another interesting note here is that that longer a raindrop gets to sit on the plant, the stronger the petrichor scent will be! This is why lighter rainfall creates a more potent smell as the rain isn’t consistently falling off of the plant and being replaced by new falling raindrops.

The last component is found in the atmosphere in the form of a thunderstorm. Lightning is a powerful force of nature. So power, that it can split molecules apart in the air! Oxygen (O2) molecules are torn apart into individual atoms. These free-range singular oxygen atoms then combine with other nearby O2 molecules to create O3 molecules. Sound familiar from chemistry class in high school? 03 is the chemical compound for Ozone! This helps to create that “pre-rain” smell ahead of an incoming thunderstorm.

Stay up to date with our WANE 15 Forecast to find out when your next chance to smell petrichor could be!