Silent, PG has long been used in inhalators for medical breathing machines -- I seriously doubt there is
any health risk from PG (I frankly worry a bit about VG, since it is, after all, oil-based).
That said, I have read where folks will add a few drops of distilled water to thin out their VG juices -- and some vendors have perfected "thinning down" VG to the point where it no longer kills cartos (or so I've heard -- I can't personally
vape anything over 35% VG). Virgin Vapors is one such vendor, I believe.
Good luck!