The scent of rain
The scent of rain has a name. It’s called petrichor from the Greek word, “Petros” meaning stone, and “ichor” meaning fluid that flows from the veins of the gods. The scent comes from the chemicals ozone and geosmin. Humans are super sensitive to geosmin and can pick up the scent at a level of 5 parts per trillion. We can smell ozone at a concentration of 10 parts per billion.
We are more sensitive to this earthy smell than sharks are to blood. Sharks can only smell one part of blood in a billion parts of water. Humans are 200,000 times more sensitive to geosmin.
That’s one amazing super power.
Camels in the desert rely on petrichor to locate sources of water such as oases—perhaps our super sensitivity to the smell of rain is for the same reason.