Hi Deeo,
After I read some of the research on the sterilization properties of PG
http://www.time.com/time/subscriber/article/0,33009,932876,00.html I asked my husband to try vaping. He quit smoking about 20 years ago and he had lung surgery about 15 years ago. The surgery removed 1 lobe of his left lung due to a hamartoma (a begnign growth, probably had since birth but blocking airways and causing him to have severe doubling over type cough attacks and recurrent pneumonia).
Even after this length of time, he still has quite bad cough attacks (scary really because he almost can't breathe). He has seen specialists and had all kinds of testing and inhalers for asthma and soon will go for an MRI.
I was at my wits end, so I made my own DIY (90% PG 10% VG and Tahitian Vanilla from RTS - no nic)and asked him to try it out. If he gets the flu, it's really bad for him. Dr. Robertson did a test with rats where he sprayed 1 cage with the flu and vaporized PG and another with just the flu. The rats from the PG cage all lived and the rats that didn't get the PG all died.
My husband had been vaping about a week or so, a bit almost every day in the evening and he has noticed a difference. I'm no scientist that's for sure but when he used to cough, he'd hack up alot of "crap", not brown crap, just clear crap..and alot of it. Sorry to be gross but he's not doing that as much anymore. I find high PG quite drying and I think that maybe this has something to do with it.
He'll be seeing his specialist soon so when/if he does have some sort of xray or test, I'll let the forum know.