Eli5: Why sometimes it is hard to get rid of the smell even though you cleaned and removed the source causing it?

Question

Eli5: Why sometimes it is hard to get rid of the smell even though you cleaned and removed the source causing it?

In: Chemistry

Answer 1

The actual source of the smell does not enter your nose, only molecules from the source. Eliminating those molecules is tougher than eliminating the source of the molecules.