In the UK the NHS is advocating for vaping as a way to stop smoking, and it works. Also, i don't know where you get your information about VG and PG (especially regarding their toxicity), but i am more than sure that your information is outdated/obsolete by now.

A large part of your cells walls are made out of vegetable glycerin. The LD50 for rats is about 12g/kg body weight (mice 8g/kg) when ingested (so about 1kg for a 100kg human), and the seen adverse effects when inhaling were minimal and only visible in hourlong exposures at the highest tested concentration.

Propylene Glycol has an even higher LD50 in rodents (20 GRAMS/kg b.w.) and is in use in every theatre in the world for fog and smoke effects (in HUGE volumes in contrast to vaping - i vape a lot and am somwhere between 5-10ml VG/PG 1:1 per day) for ages now, and there would have been found a correlation between stage workers and lung cancer by now. It's widely used in the agricultural sector as a feed additive in pretty large quantities too.

you get acrolein when the e-cigarette overheats. modern devices should not even really do this anymore. The heavy metals are a hypothesis i heard in the beginning and for which i haven't seen any source in the last 5 years. At least if you aren't overheating your NI80 coils on purpose to a dull red glow. all my homies use SS316 for smooth automatic temperature control :-)

I'm with you regarding the aroma additives (which i assume you meant as source for aldehydes); not many of those have been tested regarding inhalation (except for aromatherapy probably), and they might prove to be detrimental. i also believe that if i had kept my pack or two a day hobby for much longer, it would have had a real chance of killing me. i am also advocating that this stuff should be 18+ - by that age the whole "peer pressure" thing that led to me starting smoking with 14 should be mostly over.

in the end, the most important part is: i choose to use e-cigarettes since it's harm reduction in comparison to smoking (and nothing else worked for me), and i know that it would be healthier not to do it. cats don't have much choice regarding their food, especially when combined with an religiously motivated owner.