When we smell rain coming, what are we actually detecting?

Question

You know how when heavy rain is approaching a couple of km away, even when out in the countryside suddenly you can smell it, and sometimes quite strongly...?

What is that about? I mean...it's air+water, so what is causing the distinctive smell?

Thanks!

Answer 1

It is due to the pressure drop in the atmosphere, Barometric pressure drops around large storms (I live in a hurricane area) when the pressure drops the air is easily saturated with moisture which carries heavy smells like grass,mold, and anything else into the air where it is able to rise up since the pressure isn't holding it down. That distinct smell and sensation is from everything around us. We are animals too, it's part of survival to know when all hell is about to break loose overhead :)

Answer 2

I never thought I would see the Self Service Science Forum linked on Y!A. I was just about to say that the main smell was a gas called petrichor when someone linked to a site where I had already said it.

Answer 3

Low flying rain clouds carrying condensed smoke and fog with the rain gives off that smell and in most cases not very strong depending where you live.

Answer 4

It is ozone from the lightning as well as the smell of bacteria released from the ground as the rain (approaching with the storm) hits the ground.

Answer 5

Your olfactory nerve is responding to the collection of negative ions associated with storm fronts. The smell is sweet...

Answer 6

moisture in th air which makes you get the feeling that rain will be coming.

Answer 7

The moisture in the air; I can't describe it except to say that it smells...wet, do you know what I mean?

Answer 8

Ozone.

Answer 9

rain kummming