I got that answer too, and I don't think that is the right answer- I now beleive the key is the amount of Glycerin used- Glycerin produces a thicker denser vapor that lingers much longer if more is used- cut down on the Glycerin, and the vapor will be much less dense, and evaporate much quicker- I've tested this myself with my mixtures- when I use more Glycerin, the clouds are much denser- last in the air longer, and doesn't dissipate in the lungs nearly as quick as when you lessen the amoutn of Glycrin