The smell of the air after a storm is caused by Geosmin: a chemical released by dead soil bacteria. Humans are sensitive to it, capable of detecting concentrations ~5 parts per trillion. It's theorised in our evolutionary past this helped us seek out water https://t.co/ssYs59LklV pic.twitter.com/IX2D07uBsN

— Massimo (@Rainmaker1973) March 18, 2022