In Guyana those who live in the countryside can always look forward to going outside after a shower of rain to enjoy that invigorating smell in the air. Actually, if you are outside just before a downpour you can also detect a subtle fragrance in the air. That is the smell of ozone, a form of oxygen.
But the magic of which I speak happens after an earnest shower of rain. There is a lingering smell of earthiness which we find comforting and enjoyable. The rain hitting the ground causes a certain bacteria, abundant in healthy soil, to release a chemical called geosmin into the air. Humans are very sensitive to the primitive and primal scent of geosmin. It is theorized that this smell guided our ancestors to fresh pastures and food. Indians from Uttar Pradesh have for a long time been able to trap geosmin into a perfume which they called “attar”.
Geosmin is also present in the food chain. Some vegetables have it in their chemistry which gives them an earthy taste. These vegetables include beetroot, potato, tomato, and sweet potato. The same for certain fresh water fish such as catfish, trout, tilapia, patua. Vinegar can be used to wash out the taste.
How about the smell of freshly-mowed grass? This is a different ballgame altogether. The fragrance which reminds us of sunshine, warmth, and the outdoors is actually the smell of compounds released by the grass to heal itself from its injury. Some say the smell is also a warning to surrounding grass but I am not sure what its neighbors are supposed to do with the information.