We don't really disagree. Everything you ingest, in part, ends up in your lungs because of the gases. This is one of my points. The way I vape is to absorb into mouth, then inhale, and we do know that the bulk of the ingredients are absorbed in the mouth, nasal passages, etc. Now the issue of nutrients to protect your lungs is a different, and a far more important subject, from my point of view. Dr. Micozzi, former leader at NIH, has much detailed research on smoke and other compounds that make their way into the lungs. The body is pretty amazing at dealing with these issues to a point. Example, 10 analogs a day or less had no measureable affect on health compared with a non-smoker, the lone exception being a slight uptick in oral cancer. We now know that oral cancer is more commonly caused by HPV. In the same report in 1984 that found a dubious link to lung cancer and smoking, two cigars, or two pipes per day, for example showed slightly better overall health than a non-smoker. Micozzi postulates that the human organism adapted to smoke filled campfires thousands of years ago and does an amazing job of keeping us healthy. If you get a chance review his work, Marc Micozzi, as he was one of the first reviewers at the FDA to see the famous 1984 report, the largest health report in history to date, and it has some startling conclusions that reveal that all of the data and science is politically motivated. If smokers get lung cancer, for example, how come 90% of smokers don't get lung cancer? And, if smoking alone causes lung cancer, how come 1% of non-smokers get lung cancer? My point is that the perfect storm that causes catastrophic illness is now thought to include multiple triggers and not just too much PG or VG, for example.
Like everything else in health, too much of anything can be deadly. So, I'm not saying there's no affect, but factors such as how much, technique, frequency, ratio, etc. are important in this determination. I read your disclaimer and have done boatloads of research in this area in related fields (and not for vaping, per se), and if I felt like we were really doing harm, like combustion harm, I wouldn't vape. What would be the point? We're not in disagreement, but since all studies to date have not provided any negative results in this way, the original arguments all stand, i.e., better than smoking, few known risks, akin to caffeine, and two, if risks considered unacceptable, regardless of science, known or otherwise, don't vape. I maintain these premises. When will the studies be done? Who knows? And more importantly, by whom? But, again, if I were worried about it, as you may be, I wouldn't vape. Frankly, if you eat the standard American diet, the risks to your health have to be at least two orders of magnitude more dangerous than vaping. So, start vaping more, and eating less bread, et al. My two cents.