FIRST OFF LET ME STATE THIS: I 100% agree that teens should not be vaping. However, the amount of teens smoking has dramatically decreased. I am not saying one should be traded off for the other, but there certainly is reason to believe it has decreased due to vaping.
The truth about popcorn lung: So, in the entire history of mankind, the ONLY 8 people have ever diagnosed with popcorn lung and all worked in a plant that made microwave popcorn. It is BELIEVED that it came from an ingredient called diacetyl which gives popcorn it's butter flavor. It was discovered in a Harvard Study conducted in 2015 that some E Liquids do contain trace amounts of diacetyl (almost all of the E Cig industry has since removed flavorings contain diacetyl since this report it should be noted). So the narrative was that Vaping could lead to popcorn lung.
The actually truth is that there has been NO evidence to show that Vaping leads to popcorn lung. In fact, NO ONE has ever been diagnosed with it from vaping. And something that may surprise you is that the levels of diacetyl in a normal cigarette is over THOUSANDS of times higher then any E Liquid tested. E Liquid contained roughly 9 micrograms of diacetyl while traditional cigarettes show 6,718 micrograms of it. And to date , NO ONE has been diagnosed with popcorn lung via smoking either.
AND believe it or not, non-smokers may be more at a risk then people who vape or smoke according to one study from 2012:
"Moreover, a separate study about occupational popcorn lung published in 2012 paradoxically held that non-smokers may be at higher risk for popcorn lung than smokers are:
The 2015 research from Harvard omitted comparison to a far larger and more established control group of smokers when asserting concerns about diacetyl, popcorn lung, and e-cigarettes. Prior research into tobacco cigarettes (which contain measurably higher levels of diacetyl and are more commonly used than e-cigarettes) determined that smoking is not a risk factor for popcorn lung, so the lower concentrations of diacetyl in e-cigarette juices are not likely a risk factor in popcorn lung."
https://www.snopes.com/fact-check/vaping-causes-popcorn-lung/