Why is there always a stinky smell before it rains?

Question

Today when I went outside, it was raining, and even though I notice the smell, I never really thought about it, but today I was determined to ask, when it rains, or is going to rain, what in the world is that stench, where does it come from?

Answer 1

just a musty smell...kinda like an area that is not use to having water..all of a sudden having lots of water

Answer 2

Normally, a spring rain smells very good.  But if you are in a congested city or a swamp land the smell can be disgusting.

This is maybe because of pollution at ground level in cities and of stagnant sitting water in places near-by you.  Also, I've noticed that places with an abundance of vegetation do not smell very good but places with dust smell very good.