Humans can smell rain better than sharks can smell blood, and it’s all because of something bacteria, algae, and fungi produce.
Called geosmin, it is a chemical compound produced by certain types of bacteria, algae, and fungi, and if you are human, you can detect the scent of geosmin in very low concentrations—as low as 100 parts per trillion, according to a study in 1992.
This is compared to animals like sharks that can detect blood when it is only one part per million in the sea.
A chemical compound produced by certain types of bacteria, algae, and fungi that live in the ground or on other surfaces, geosmin is released when raindrops hit the ground or other surfaces, disturbing the soil or other environments where these microorganisms reside. This releases geosmin into the air, which contributes to the earthy and musty note that is synonymous with the smell of rain or petrichor….