So... about the residue thing. I had assumed no residue but it seems I was wrong. I am thinking of what might happen in the lungs regarding this residue issue, from a health perspective. I would hope the lungs would be able to move the residue out without any complications? I certainly can have a heavy evening of chain vaping and feel heavy chested the next day, but that passes after a period of abstinence. Need I worry? That's assuming it's not an unknown
We have sound, logical reasoning for belief that vaping is much safer than smoking. Because there's no fire there's no smoke, and no resultant thousands of potentially carcinogenic chemicals produced by combustion.
Are the substances we're inhaling safe from a health perspective? We can't say that, but the basis for the assumption that it's safer is solid.
If you are worried about potential health effects of vaping, try changing your inhalation technique. Don't draw deeply into the lungs. Instead, draw slowly like you would on a milkshake straw and exhaling through the nose, or draw just into the nasal and esophageal passages and hold it there for a second or two. The nicotine rush is actually more pronounced with this technique, and none of the vapor is drawn deeply into the lungs.