Let's review what's in our e-liquids:
With regard to PG, if you were born in a hospital, the first breaths you drew on this earth were well laced with PG -- it's been in use in hospital ventilating systems for many decades. PG is a germicide.
It's mostly been replaced with micropore filters.
Also, many surgeons and OR nurses have spent 12 hours per day, five or six days per week in operating theaters for their whole careers, and operating theaters used to get really heavy doses of PG via the ventilation systems. And an awful lot of stuff we breathe, put in our mouths or eat are well laced with PG.
The FDA has called it "generally recognized as safe."
Has she ever been to a disco, or rock concert where there's a "fog" machine pumping out the "vapor".
Guess what creates the "vapor"..... the same thing your vaping.
With regard to VG, you find it in an awful lot of foods, both natural and processed. For instance, nearly all wines have an appreciable amount of natural VG. All told, you've probably ingested gallons of the stuff over your lifetime. The FDA has also called VG "generally recognized as safe."
If she wears lipstick, she is "vaping" as she wears it off.
Nicotine, well you'll have to draw your own conclusions, but from what I've read, it's not a carcinogen, just a mild stimulant which has other beneficial properties for certain people.
It's probably not good for you if you have an advanced case of congestive heart failure or blood pressure high enough to pop your eyeballs out of their sockets, but otherwise it's a "so what?" on the order of caffeine.
It also needs to be remembered that nicotine is a normal and natural part of the diet.
Everyone tests positive for nicotine in the blood and for its metabolytes in the urine.
There has never been a large-scale clinical trial of nicotine where anyone tested negative for nicotine.
The last test by the CDC in the USA involved 800 subjects and all tested positive for nicotine at measurable levels, even where the subject was a non-smoker, had never smoked, and had no possible contact whatsoever with smokers.
The reason for this is because many vegetables contain nicotine, and also the co-located and similar compound nicotinic acid (also known as vitamin B3 or niacin).
Tomatoes, potatoes and several other vegetables all provide dietary nicotine.
Tea often contains nicotine, which after all is one of the reasons it works as a pick-me-up.
Some vegetables such as aubergine (eggplant) contain significant amounts.
These vegetables are broadly (but not exclusively) members of the Solanaceae family, one of our most often-consumed vegetable groups.
Nicotine is a perfectly healthy, normal and natural part of the diet.
Some individuals may need more than the usual dietary quantity, as is observable for many other dietary constituents.
Just as some may need a very large supplement of 2,000mg of extra vitamin B3 (nicotinic acid) in order to normalise cognitive function, short-term memory and work capacity; so a similar increase of nicotine may be necessary for such persons.
This has been demonstrated by clinical trials that showed the positive effects on stress, work capacity, memory and cognitive function for some individuals.
Although research in this area is sparse at this time (due to the unfashionable reputation of nicotine since it tends to be conflated with smoking), it is reasonable to expect that:
Some people need more of a specific dietary component than others; it is why people take supplements.
Since similar effects can be shown for nicotine and nicotinic acid (vitamin B3), it seems possible that those who demonstrate a requirement for supplementary B3 may also require supplementary nicotine.
No one has ever demonstrated:
a. That nicotine is harmful in reasonable quantities - many vitamins or dietary ingredients are of course toxic or even fatal in large quantities, such as vitamin A, vitamin D and iron, so that this is a non-argument.
b. That nicotine is any more harmful than coffee (caffeine).
We know from the Swedish national health statistics that ad lib long-term consumption of nicotine by tens of thousands of people over periods of decades has no identifiable risk.
The key to all of this is to remove the smoke.
Without the smoke in cigarettes, consumption of certain specific types of tobacco (and, especially, nicotine consumption alone) can be proven to be ultra low risk.
If a large population of people consume nicotine ad lib for decades with no visible health impact, then the issue is not debatable.
Flavorings are the only real wild card: there's just not enough experience with inhaling these over a long period of time. But they're all safe to eat.
The heat to which we subject e-liquids is not enough to cause any of these ingredients to form new, noxious compounds.
And, remember, your lungs are not garbage cans!
Something you inhale just doesn't sit there until the day you assume room temperature.
Since you've quit cigarettes, all the little ciliae in your lungs and bronchial passages have become unparalyzed, so they constantly shove anything your lung tissue doesn't like up your windpipe to the point where you either cough up the offending goop or swallow it.
Isn't it great that the lungs can clean themselves, and you don't need to worry as much about that guy sneezing , as your mouth and nasal passages are coated with a germicide.