Thursday, December 26, 2013

Do E-Cigarettes Cause Passive Vaping?

“Passive smoking” has been hotly contested. Is there a case for “passive vaping”?  Hardly.

A detailed study of e-cigarette vapor by German investigators at the Fraunhofer Wilhelm-Klauditz-Institute’s Department of Material Analysis and Indoor Chemistry detected virtually no quantifiable levels of 20 volatile organic compounds (VOCs) present in cigarette smoke (abstract here).

They had a volunteer smoker puff three e-cigarette liquids and one combustible cigarette in a cramped test chamber measuring about 6 feet cubed.  The volunteer took six, deep 3-second puffs on each item at one-minute intervals; air samples were taken for 15 minutes after the fourth puff.

These are the results for the 20 agents with the highest concentrations. 

Concentrations (ug/m3) of Volatile Organic Compounds (VOCs) in Vapor From Three E-cigarette (Average) and Smoke From a Cigarette
VOCE-cigarette VaporCigarette Smoke
Propylene glycol*112
1-hydroxy-2-propanone *62
Acetic acid1368

*Unquantifiable/same as empty chamber

Five VOCs were detected in e-cigarette vapor at minuscule levels.  The level of formaldehyde was similar to that measured before the e-cigarette puffs, leading the investigators to comment that it “…might be caused by the person in the chamber itself, because people are known to exhale formaldehyde in low amounts.”  Acetone and acetaldehyde may have resulted from combustion of propylene glycol during e-cigarette puffing, which also occurs to a larger extent during smoking.  Propylene glycol, a major component of vapor, was not present in the chamber during-after e-cigarette use. 

Although the investigators aimed to identify VOCs “under near-to-real-use conditions to estimate the effect of ‘passive vaping,’” the use of a 6 foot cubed chamber is not real-world.  They answered their title question, “Does E-cigarette Consumption Cause Passive Vaping?” in the affirmative, but these barely measurable results, extrapolated to rooms of normal size, confirm that bystanders have virtually nothing to worry about from vapers.


Chris Price said...

This study is confusing because it uses several different chambers, and the discussion/conclusion is sometimes not clear as to which is being referred to; and although compounds were below detectable limits in the 'real' vaping part of the study in a tiny box room, the conclusion, confusingly, does not align with the measurements (the conclusion is that 'passive vaping' exists even though no detectable amounts of hazardous compounds were present in the vaping chamber); the conclusion, instead, seems based on pumping vapour into a 10 litre flask to detect measurable amounts of anything potentially interesting. (In other words, 2nd-hand vapour is virtually undetectable, but if we take concentrated vapour and pump it into a tiny space then we can conclude whatever we like.)

There are some other issues, such as that the principal ecig tested seems to have been a zero-nicotine product, for some reason.

For those not familiar with the terms, propane-1,2 diol = propanediol-1,2 = propylene glycol, and propane-2,3 triol = propanetriol-2,3 = glycerine.

The study has been praised and criticised elsewhere, by alternately picking facets seen as positive or negative for vaping. Perhaps the researchers were trying to please different audiences; the total effect seems confused. Tests needed to be carried out with a nicotine product in the main series, but weren't; and the discussion and conclusion should have been based on the realistic chamber testing, but instead referred to various aspects of testing done with different products in different chambers. All in all a bit of a mishmash. I suppose the takeaway is as you describe: no apparent risk for 'passive vaping'; but there is plenty in there for others to make whatever they wish to out of it - since the tests were so numerous, mixed up, and confusingly referred to. No doubt this is why you published the current article.

Research of this type just contributes to argument, unfortunately. There are numerous problems with this study, starting with a lack of planning, and finishing with a confusing write-up. It's true that one conclusion is that 2nd-hand vapour is not problematic (when measured as per the main part of the trial); another conclusion is to take any of the other measurements and/or confused commentary, mix well, and get whatever you like. Some useful research, presented very poorly.

CP said...

addendum: the full text can be seen at:

Rursus said...

Hey Prof!

Have a closer look at the work of Fr. Ann Diskin et al.:

The measured VOCs of Schripp et al. are presumably normal metabolites of the human being inside the chamber!

Rursus said...

Another study:

Cite: "In non-smokers, exhalation contains FA in the order of 0.001 to 0.01 mg/m3(Kushch et al., 2008;Moser et al., 2005; Wehinger et al., 2007)."

The "12ug Formaldehyd" mentioned by Schripp et al. are definitely normal metabolites of the human being inside the chamber!

sean said...

No e-cigs don't cause the passive vaping..

amy said...

e-cigs don't cause passive smoking, its not harmful for other people.