Next time your out bush,,, or driving along a road and come across a rotting carcass and it's stinking to high heaven,,,,, consider this.
A "smell" is actually composed or made up of microscopic particles of the carcass itself that have become airborne.
Usually most people, when they first get a whiff of it,,,,,,,,,, take a further sniff and then say something like "Jeez, that stinks, what is it ?"
If your a bit weak in the stomach,,,, appreciate the fact that you've just ingested part of that rotting carcass.