I wish it was just BS, but PG and VG (which are so similar there is literally only 1 ATOM difference between them) have been documented to break down into aldehydes at high temps DECADES before vaping was even invented. Now that is not to say that all of these studies were above board. Some of them (especially the ones you mention where they are burning coils) could have known this going in and purposefully created favorable conditions for this to occur. I will also agree that unless these studies also accounted for aldehydes already present in the air, that some of these could be tainted unintentionally. However, we also cannot just completely discount a proven chemical process just because we don't like the result.
Chemical formulas:
PG = C3H8O2
VG = C3H8O3 (note only 1 extra oxygen atom vs PG, otherwise identical)
Formaldehyde = CH2O (now look at the PG and VG and tell me you see no way for those to become this)
First, not all aldehydes are dangerous or carcinogenic. Lets get that perfectly clear. Formaldehyde is considered potentially so (although not all studies agree to what extent), at certain levels and in certain combinations with other carcinogenic chemicals.
Just because these vaping - formaldehyde studies show that a molecule is being produced, in no way shows that they are produced in dangerous quantities. In order to demonstrate that, they would at least have to get their units in the same ball park as other studies. They are comparing strawberries to bowling balls atm, and trying to convince us that cubic fortnights per square inch make some kind of sense. It does not. Fortnights and square inches are entirely different units which measure entirely different things just as micrograms compare to ppm.
Also, take into consideration that anything can become dangerous in a sufficient quantity. A drink of water is good for you and necessary to sustain life, several hundred thousand gallons of water probably not so much. Oxygen seems to be good for you, but it destroys iron because its so highly corrosive.
The problem with formaldehyde, is that we don't have studies comparing vaping to what would be considered accept levels of air exposure, which is measured in ppm. in order to do that, you would have to know how many liters a microgram of formaldehyde is so you can figure out how many ppm of formaldehyde you have in however many liters of lung you have over, say, the course of an hour. All this can be computed but it takes time and work which none of these so-called scientists seem to want to take.
All that said, we also do not know if we are actually metabolizing any formaldehyde in a sufficient manner for it to be carcinogenic to us. According to the American cancer society inhaling formaldehyde at levels at a concentration of 1.9 parts per million (ppm) for 40 minutes did not increase blood levels of formaldehyde in humans.
Even workplace exposure to people who deal with large amounts of inhaled formaldehyde at work, although found to have increased rates of leukemia and nasal cancers, these same results cannot be consistently reproduced in a lab.. therefore we do not know if there are other factors involved in these cancers which must be present for formaldehyde to be cancer causing in humans consistently (something we can definitively point to).
As it is right now, we just don't know enough, and jumping up and down screaming formaldehyde just isn't helpful, ESPECIALLY to new vapers... when some real science is done that actually tells us something that relates to vaping, humans, and potential carcinogens, then perhaps we can worry. As it is right now I'm not willing to do anything but have a wait and see attitude until I see real science done and get to read those conclusions and the potentialities those create.
