Consider water vapour in the form of humidity. We say water is a liquid but the liquid phase can only exist if there is enough of it in vapour phase to begin to condense out.
The same is true for lead with the difference been that it requires a lot less lead in vapour phase before it starts to condense out.
Upintheassholeoftimo t1_jcd6av5 wrote
Reply to Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower
Consider water vapour in the form of humidity. We say water is a liquid but the liquid phase can only exist if there is enough of it in vapour phase to begin to condense out.
The same is true for lead with the difference been that it requires a lot less lead in vapour phase before it starts to condense out.