I thought this was interesting. I thought you may find it interesting as well.
It is called is Petrichor, and it is caused by Geosmin.
The human nose is extremely sensitive to Geosmin and is able to detect it at concentrations as low as 5 parts per trillion.
You may ask what Geosmin is? Me Too.
Geosmin is an organic compound with a distinct earthy flavor and aroma, and is responsible for the earthy taste of beets and a contributor to the strong scent (petrichor) that occurs in the air when rain falls after a dry spell of weather.
Geosmin is an organic compound with the formula C12H22O. It’s produced by several classes of microbes, including cyanobacteria (blue-green algae) and actinobacteria (especially Streptomyces), and released when these microbes die.
The smell after a rainstorm is attributed to Geosmin.