the smell produced when rain falls on dry ground, usually experienced as being pleasant.
Besides the pleasant, dewy petrichor of the post-rain afternoon, I see no hope or way out of a four-hour ride with the enigmatic mumbler. –VeloNews, the Journal of Competitive Cycling, 5 April 2004.
“They declared that they have found the earthy scent of petrichor, as if it was secretly drizzling in some deep corner of the city undetected by meteorologists. And when it rained on Monday, they smiled with pride and said: ‘I told you so.’” –Eye on Sky; The Times of India (New Delhi); Mar 17, 2016.
Did You Know?
When decomposed organic material is blown airborne from dry soil it lands on dirt and rock where it’s joined by minerals. The whole mixture is cooked in this magical medley of molecules. Falling raindrops send those chemicals airborne, right into your nostrils.
When it’s not raining the molecular mixture serves a different purpose: signaling plants to keep their roots from growing and their seeds from sprouting. No use wasting energy on all that when there’s no water to be drunk.
So why does the world smell different to humans after it rains? Because of plants, basically.
Coined by researchers I.J. Bear and R.G. Thomas in 1964, from Greek petros (stone) + ichor (the fluid that supposedly flows in the veins of the gods in Greek mythology).