When it rains after a prolonged period of dry weather, there is a smell created. It's called Petrichor. A wonderful word, and utterly useless trivia item. The smell is caused by something call Geosmin, which is produced by bacteria in the soil. Humans can smell it at 5 parts per TRILLION. In contrast Sharks can detect blood at concentrations of 1 part per million. On this one substance, we have a better sense of smell than sharks do for blood. Humans are amazing!
@quixoticgeek There's also Dimethyl sulfide which provides the smell of the sea, which is flamable. detectable at 0.02 to 0.1ppm and associated to cabbage. The ocean smells like cabbage! 😁
@quixoticgeek ...and some puerh tea, but usually not considered a bad thing. @wmd