The Burstyn study "peering
through the mist" has this to say about exhaled vapor:
The cautions about propylene glycol and glycerin apply only to the exposure experienced by the vapers themselves. Exposure of bystanders to the listed ingredients, let alone the contaminants, does not warrant a concern as
the exposure is likely to be orders of magnitude lower than exposure experienced by vapers. Further research employing realistic conditions could help quantify the quantity of exhaled aerosol and its behavior in the environment under realistic worst-case scenarios (i.e., not small sealed chambers), but this is not a priority since the exposure experienced by bystanders is clearly very low compared to the exposure of vapers, and thus there is no reason to expect it would have any health effects.
And:
It has been suggested that
propylene glycol is very rapidly absorbed during inhalation [4,6] making the calculation under worst case scenario of all propylene glycol becoming available for inhalation credible.
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And this points to the assimilation that occurs in one's lungs as well as the desiccant aspect of PG and VG where a displacement occurs resulting in what some studies have said to be "mostly" (or Roly's 66%) water vapor (for exhaled vapor). And I expect that displacement is also the reason why certain studies have said that the amount of nicotine
in second hand vapor is unable to be measured with instruments that measure to "< 0.001" (in the 'Clearstream study' by Dr. F). Amount of PG measured " < 0.01" .... same study. Again, this is for second-hand vapor not mainstream vapor.
As I've said before (and it will vary from vaper to vaper) but IF such a displacement
didn't take place either via mucus membranes in the mouth/throat or in the lungs, with the nicotine, then we'd still be smoking

And... the reason nicotine can't be measured in true real life type second hand vapor, rather than with smoking machines that only approximate mainstream vapor - that which the vaper experiences, not what bystanders may experience, which is, by these studies, no effects whatsoever as far as the nicotine and PG is concerned.
It's possible that some flavoring can be detected, but in my experience even that is relatively a small percentage of flavors - RY4, coffee, and a few others -
vs. almost any other smell that is rendered by humans, whether garlic breath, body odor, cigarettes, perfumes, etc. - iow, out of those, ecig vapor is the very least and contains no appreciable level of contaminants and sometimes no measurable level of them.
http://publichealth.drexel.edu/~/media/Files/publichealth/ms08.pdf
http://clearstream.flavourart.it/site/wp-content/uploads/2012/09/CSA_ItaEng.pdf