posted by Carl V Phillips
I have to leave my series on what constitutes useful evidence as a cliffhanger for another day or two, because people are clamoring for my comments on the latest in the series of studies about e-cigarette vapor chemistry that was recently published. (Article summary here; full version is paywalled.) The study tends to confirm what we already knew about vapor, and the fact that it does not contain important quantities of unexpected toxins. This is certainly good news for e-cigarette users (vapers) and THR advocates.
Before continuing with the study, though, it is worth tying this in to the current series I interrupted and asking, “How did we know that?” The bulk of the evidence comes not from the half-dozen or so lab studies that have been done, but from the basic chemistry and physics of the situation.
That is, how do we know that e-cigarette vapor is not similar to cigarette smoke? The same way that we know that it is not similar to monkey urine — with our scientific reasoning process that says, “Why would we ever even expect it to be similar?” Cigarette smoke is produced by burning complex plant matter which produces a lot of the many known products of combustion and a little bit of more chemicals than we could ever count. E-cigarette vapor is produced by heating a liquid of (mostly) known chemistry, very much not like plant matter, into a vapor phase with little change in the chemistry other than its physical state. The best evidence that we have that they are different is right there in that reasoning.
One of the biggest mistakes that THR advocates can make is to implicitly endorse the anti-scientific tactics of anti-THR activists, who would pretend that most of the evidence does not exist. In other words, it is a potentially fatal error to send the message, “Because of this study and the handful that came before, we know…” rather than the more accurate and useful observation, “Before the first study was ever done, we were 99% sure that…, and these studies show that, indeed, we did not overlook anything in our previous reasoning.”
If you live by the one-off little study, you will die by the one-off little study. There is an obvious response, by those who seek to prevent harm reduction, to all of the chemistry studies that have been done (including those spun by the anti-THR liars, which have actually shown the same good news as the others). They can say, “these only looked at a few samples of the product, and we do not know what might be in other or current products.” This is a reasonable response, though ultimately not true.
It would be completely true if I had phrased it differently, substituting “they do not provide observations about what might be in…” rather than “we do not know what might be in…”. “We do not know” is a lie is because of all the rest of our knowledge, apart from the handful of studies. But if we seem to be claiming the handful of studies are what really matters, we are arguing the liars’ case — after all, eventually one of these little studies will get a bad result due to lab error or real contamination.
Circling back, what is contained in the “…” a few paragraphs back? The main observation there is that e-cigarette vapor contains the same stuff as e-cigarette liquid (disbursed into air), in obvious contrast to cigarette smoke, which is obviously not just the contents of an unlit cigarette plus air.
Should we be worried about unwanted chemicals in e-cigarette vapor, then? Well, basically: garbage in, garbage out. That is, whatever is in the liquid will end up in the vapor. If the liquid is contaminated with something that should not be there, it will also be the vapor (though this creates approximately a zillion times as much concern for the vaper herself as for any bystanders for reasons elaborated upon below).
Is there some chemical activity that might depart from this observation? Not much, but perhaps some. And therein lies the very unfortunate limitation of the new study. Its value would have been dramatically increased had they analyzed the chemistry of the same liquid that was used to produce the vapor, a step that would have been quite easy and inexpensive. Any important differences would give us new (because it would be unexpected) information that might help in creating better products. If there result were the expected correspondence, however, it would help reassure us that studying only the liquid chemistry (much easier and quite practical to do for samples from every large-scale production run, and for some portion of small batches) would be roughly as useful as more complicated aerosol studies.
Of course, that tells us what the vaper is exposed to, rather than those sharing space with the vaper (who we expect will breathe some of whatever was exhaled by the vaper, just as we always breathe whatever people around us are exhaling). This is important because much of the rhetoric coming from the anti-THR liars claims that the exposure of bystanders justifies enacting bans on the use of e-cigarettes in public, and even private, places. But the exposures of bystanders are going to be attenuated compared to vapers by both dilution (a little bit of vapor in a lot of air) and absorption (most of the content stays in the user unless he is intentionally quick-puffing in order to make a cloud rather than to more effectively deliver nicotine by holding the vapor longer).
The recent German study — which was spun by the authors’ and others’ anti-THR lies (links above) as showing a serious risk to bystanders when it actually showed quite the opposite — looked at exhaled vapor, providing a better measure of the actual environmental exposure. The new study, unfortunately, just diluted the vapor that the vaper would inhale, a rather odd arbitrary methodology. This was apparently supposed to offer some measure of what a bystander would be exposed to, but it fails to do that. Mostly what it does is make all of the quantitative results meaningless, except in relation to each other. The arbitrariness is clearly illustrated by considering what would happen if, instead of diluting the vapor into roughly half a cubic meter of air [the rest of the paragraph is UPDATED based on first comment] and then apparently multiplying the concentrations as if this were diluted to a 40 m^3 room, they had diluted it into a different volume. In an alternative scenario, the concentrations would have all been changed by some multiplicative factor, assuming we ignore any actual effects of the room (gravity, adherence to solid surfaces). Moreover, even if they chose the “right” dilution factor (whatever that might be), this would still not mimic the exposure of a bystander (read on).
This means that only the relative results matter. The relative comparison is made is to cigarettes smoke, but we already knew that there was a big difference. The comparison does not answer the question about whether the real-world concentration of chemicals from e-cigarettes is “too much” (whatever that might be judged to be by a hypothetical rational and honest policy process). A similar observation about the sensitivity to the dilution mattering is true for any study of vapor (or smoke) also, but in this case the dilution factor was utterly arbitrary. It was far smaller than a room['s dilution given that that large number of puffs represents a lot of vaping time], but far larger than someone’s lungs.
I bring up lungs again because, despite how this study was spun, this was a study of “first hand vapor” not “second hand vapor”. The methodology description is a bit incomplete, but it is pretty clear that there was no attempt to simulate the process of the vaper absorbing most of the content of the vapor or a smoker absorbing the smoke to which it was being compared. Yet the press release had the very unfortunate headline, “New e-cigarette study show no risk from environmental vapor exposure”. The second-biggest flaw in this headline is the reference to environmental exposure, which was not studied. Unfortunately, two of the people quoted in the press release make the same mistake as the headline, with one of them even making the error of referring to “second hand vapor”.
Of course, if what the user is exposed to does not contain anything we should be worried about, then the much lower exposure of the bystander is even less worrisome. But, again, we know that because it is obvious for numerous reasons, not because of this study.
Finally, there is that “no risk” claim. This is another example of the overblown claims that — as I argued previously — will ultimately harm the cause, not help it. First, a chemistry study is not a health study, and does not include any measures of health outcomes. This study looked at more results than the example of overblown claims I cited in the previous post, but that other study had the advantage of measuring health outcomes. A claim like “found levels of environmental exposure that are not considered worrisome for health” would be fine, but no actual health claim can be made based on chemistry results like these.
Second, the claim “no” (as in “no effect”) is never a legitimate scientific claim. “Too small to measure” — great. “Showed no evidence of an effect” — fine. But we can never be sure there is no effect. It is generally suspected that nicotine is a little bit harmful, though the effects are too small to measure. Some people are definitely sensitive to polypropylene glycol exposure. Further similar observations can be made about the contaminants. So if someone breathes enough of the vapor (and, again, the absolute concentrations that were measured were totally arbitrary), there could well be some harm. Nothing is gained by pretending otherwise.
Finally, as a policy analyst, I have to strongly object to treating natural science results as if they provide policy analysis as was done in the press release (though not in the actual article). Do these results show that we should not ban vaping in any indoor spaces? Definitely not. Nor would have less-reassuring results shown that we should ban indoor vaping in some indoor spaces. Such claims require both a statement of the ethical basis for imposing restrictions on people’s choices and the accompanying economics (assessment of costs and benefits) which would be informed by the natural science results. That requires several more steps than are ever included in a research report.