Unfortunately, all I got from that post you linked to was that tests have been done, but all the data is incorrect due to poorly-run testing. The only thing in that post that "tells" us anything is pretty much a "best guess" by the OP (based on the tests the OP says are all skewed anyway?).
It would be nice if someone (an objective laboratory with *no* interest for or against e-cigs) could do some studies on what we are exhaling into the air around us. I, for one, would like to know more than just "oh it's mostly water vapor". I'm not that concerned about the PG/VG, but I would like to know how much of the nicotine actually makes it back into the air, and the effects of this occurring long-term.
I have heard of people that have been vaping for a while (can't say exactly how long) that have cleaned "yellowish gunk" off their computer screens, etc. This would imply that some nicotine is getting back into the air and over time that nicotine will build-up on things (or in other people/pets lungs?). But is it enough to be harmful? These are the things that concern me.
Of course, you are right, but the problem is these are the only tests that have been done on vapor - as far as I am aware. It's down to money in the end, naturally, and a basic trial costs $75,000. Up to now there hasn't been much interest in running trials except by one or two manufacturers, and as you can see they didn't realise that not only would they need to fund such a trial, they would need to closely manage it, because laboratory staff have universally proven less than able to produce the goods - in these and other trials.
In fact, the one thing that all the various trials up to now have proved is that no matter what laboratory is involved or which academics are running the trials, the research will be mismanaged and produce less than useful results unless experienced electronic cigarette users are present.
If you go to the NVC forum here, you'll find they are in the process of setting up the first community-funded trials (IVAQS) that will address these issues. You are strongly encouraged to donate to this project.
Film on windows: anything you can see in the air can potentially condense on or attach to surfaces it comes into contact with. Due to the percentages in the vapor I think that flavorings are likely to be the most prevalent constituent of the film left by vapor, followed by a tiny amount of PG, VG and nicotine.
At this stage - without definitive research - vapor straight from the e-cig looks to be two-thirds water, small percentages of PG, VG and nicotine, and the bulk being flavoring (about 17%). What the exhaled vapor consists of is not known; one guess is that the water content will be higher as some of the solids will have been retained within the body.
It's not clear to me where all the water vapor comes from in the first place as there isn't much in the e-liquid, but no doubt it's the same as a fog machine, the water comes from that in the liquid plus that in the atmosphere. A fog machine has a larger atomizer chamber though, and perhaps this allows the creation of a greater volume of visible fog as the air volume in the chamber is larger. As we breathe out water vapor naturally, there would be plenty available to be made visible by the PG and VG.
