Considering that these ingredients PG/VG are used in medical inhalers and those vaporizer things used to help open lungs etc on sick people Id say it has to be safer than the aerosol air deodorants, or the AXE body sprays, room fresheners, Febreeze( that makes some cats loose their hair) hairsprays, deodorants, WD-40, nail polish, hair color, or even the air around us during our normal day out. THere are exhausts from our cars, airplanes, other peoples breath which might contain viruses, bacteria etc. Just think about it. PG/VG is in almost all of our body and hair products, its in toothpaste, mouthwash, and many food items. I know that inhaling is different from topical uses, but all air fresheners have who knows what in it. Frebreeze is sprayed on all of our things at home, on bedsheets, closets, etc. It has been found that many animals such at pet birds and cats have extreme sensitivities from simple hair loss and feather loss to death.
Except for those with extreme allergies to either the PG or VG or the flavorings used I think compared to all the stuff we consume in our everyday like a little
ejuice is the least of our worries.