PG is used in nebulizers and has been for quite some time. My son uses one, he's special needs. His maternal grandmother uses one in her COPD treatments.
VG is used as a sweetener in food and medicine. It is also used in suppositories, lotion, conditioner, tanning oil, sunblock, and makeup.
Your body's biggest organ is skin, you absorb water, oxygen, good and bad chemicals through it. I know talking about lungs is different but seeing how much contact one could have with VG on their body. I think drastic reactions would have surfaced long ago before e cigarettes were invented, my opinion not fact on this part.
The best thing is to not smoke, vape, abstain from alcohol, caffeine, and etc. Now breathing is something else.
I'd like to see studies showing the chemicals in vaping, smoking, and the air right outside the lab the test was done in. Post them all side by side, wonder how that would kill most arguments?
Now the best answer to your question is, only you can choose what is best for you. I'm sure you knew smoking was bad but smoked anyway, just as the rest of us. If you feel unsafe then you need to decide whether to quit, smoke, or look for another alternative to be smoke free. If I could have quit cold turkey I would have. I have spent more money on toys (mods and atties), juices, wire, etc. lol