VG will hang in the air for up to 30mins that i have seen in the arctic,,which is an extremely dry environment
PG will hang for quite awhile also,never really noticed so i cant say if it is 30 like VG.
you can see the vape clouds inside a house on a sunny day ,,when the sun is shining directly in through a window
now VG will build up quite fast on something that is colder then the rest of the room like a window ,but it won't hurt any of your expensive electronic toys