When you smell something, that’s molecules of that substance hitting your nose and reacting with the receptors in your nose. Those molecules are subject to all sorts of chemical reactions when floating in air that will eventually degrade them into something else, the same way that a piece of food left on the floor eventually gets eaten by a critter or rots/molds. So we’re not filling the world with odors; they’re breaking down over time to other, more or less odorous particles.
Latest Answers