-
Asked by spacenut to Pete, David on 10 Jun 2012.
-
Pete Etchells answered on 10 Jun 2012:
That’s a pretty good question, actually! When it rains, the water droplets in the air essentially cause various things to become aerosolised. What this means is that if there is something (like bacteria) on the ground, when rain hits it it gets kicked up into the air, and hangs in suspension in very fine rain droplets. When you breathe in, you take in these droplets, and can smell whatever it is that’s being held in there. I think that nice, fresh smell you get after it has rained can come (at least in part) from spores that are released by bacteria that live in soil!
-
Comments
Kirsty commented on :
Dropping in on another zone =) It actually has a name that was on one of the most recent episodes of Dr Who. It is called petrichor http://en.wikipedia.org/wiki/Petrichor
jbiddles commented on :
As well as this, the fresh smell is actually the smell of your surroundings, but intensified. This happens because air pressure tends to drop when it rains, allowing you to smell more of the things you’d smell normally – grass, flowers etc. – because things evaporate better at lower pressure, and it’s the gases that you can smell.