Oxford Journals: Carbonyl Compounds in E Cig Vapors

[Teach]

I found this study interesting - thought others might too.

Carbonyl Compounds in Electronic Cigarette Vapors—Effects of Nicotine Solvent and Battery Output Voltage

One chart from the study which shows measured levels from PG and VG and the effect of higher voltage. Follow the link for the complete study online.

 

[NavyNut]

I vape in the lower voltage, around 3.3-3.5, so I should be good. Interesting study for those in the higher voltage.

 

[Teach]

The lower level of off gassing when using vegetable glycerin is another good point . But I agree that the lower voltage does make a difference .

 

[kkay59]

I vape at lower settings than most. Still, this is not good news.

 

[Teach]

I vape at lower settings than most. Still, this is not good news.

How so? Personally, I rather look at it as a good study. The use of V.G. at lower voltage levels really does benefit. And if you take a look at the study they're talking about levels which are so much lower than those emitted by tobacco products its almost negligible in comparison.

Also, don't forget this study was done overseas and it doesn't appear that the hardware was the newest available now. It's possible that there could be different results using newer variable voltage / wattage equipment and newer and more efficient heads... Probably better results.

 

[Zanderist]

I think its a great study, but I think they should of measured in watts.

One issue I have is the puss lasts 17 seconds...I don't think that's realistic.

 

[stevegmu]

I think its a great study, but I think they should of measured in watts.

One issue I have is the puss lasts 17 seconds...I don't think that's realistic.

The duration is 1.8 seconds, with a 17 second interval...

 

[stevegmu]

How so? Personally, I rather look at it as a good study. The use of V.G. at lower voltage levels really does benefit. And if you take a look at the study they're talking about levels which are so much lower than those emitted by tobacco products its almost negligible in comparison.

Also, don't forget this study was done overseas and it doesn't appear that the hardware was the newest available now. It's possible that there could be different results using newer variable voltage / wattage equipment and newer and more efficient heads... Probably better results.

They used eGo 3 twists; probably the most widely used type of device for the non hobbyist vaper...

 

[Teach]

They used eGo 3 twists; probably the most widely used type of device for the non hobbyist vaper...

Good point!

 

[BigEgo]

The paper suggests that PG seems to be the main culprit here. And that makes sense when you consider that the boiling point for PG is much lower than for VG.

The authors also hypothesize that PEG 400 might be safer because they tested one eliquid that used it as a solvent and didn't find any carbonyls. Of course, one sample is hardly scientific, but they suggest this is an avenue others should look at.

And, of course, they did voltage tests and said once they got over about 4.8 volts, the levels of certain carbonyls released (formaldehyde, etc.) started approaching that of tobacco smoke. However, the number of toxic compounds seems to be less than smoke overall.

I think temperature and voltage will be a big discussion this coming year as well as whether we should rethink using PG as a solvent. I would like to see more research done on PEG 400.

 

[VictorC]

Just came across this thread.

For someone new to vaping as myself it was interesting to find that vaping at a lower voltage VG-based juice would be a "healthier" option, well at least when it comes to carbonyls consumption.

Still not sure how voltage/wattage translates into temperatures. My sub ohm coil (0.6) produces tons of vaper at 2.8V (14W). Does it mean that it produces less carbonyls than a 2.0 coil at 4.8V (11.5W)? I guess both voltage and wattage readings are meaningless when only coil temperature matters.

Look forward to seeing more studies on temperatures and PEG.

 

[pfaber11]

Since reading this study I've gone from vaping at 4.1 volts to 3.3 volts on a 2 ohm atomiser. Better safe than sorry and to be honest it's still not a bad vape. Vape on

 

[mosspa]

I found this study interesting - thought others might too.

Carbonyl Compounds in Electronic Cigarette Vapors—Effects of Nicotine Solvent and Battery Output Voltage

One chart from the study which shows measured levels from PG and VG and the effect of higher voltage. Follow the link for the complete study online.

View attachment 379695

Carcinogenicity is a tricky problem. Yes, acetaldehyde has been demonstrated to be carcinogenic in some animal models. This does not appear to affect human usage of alcohol, nor the prescription of drinking punishers such as Antabuse (that works by selectively allowing acetaldehyde to accumulate and cause sickness). Similarly, the evidence that formaldehyde 'causes' cancer in humans is even more shaky. First, in order to even suggest causality, a real scientific experiment must be performed. Obviously, such a study would be ethically impossible, so that any conclusion of causality must be based on correlational studies which can never demonstrate causality. The National Toxicology Program (NTP), did not even get around to confirming formaldehyde a 'known human carcinogen" until this year, meaning that it suspected it to be up until now.

"(The) NTP did not include a description of its interpretation of “limited” and “sufficient” evidence for human studies, which factors into whether a chemical is listed as reasonably anticipated to be or known to be a human carcinogen. The Research Council committee defined “limited evidence” in humans to be two or more studies of varied design that suggest an association between formaldehyde and a specific type of cancer but that cannot exclude alternative explanations such as chance, bias, or confounding factors." (National Academy of Sciences, Mar, 2015).

While the goals of the NTP are, indeed, lofty, their conclusions are often over-exaggerated, keeping in line with the general CYA practice of estimation in toxicology (i.e., first come up with a reasonable estimate of the actual toxicity and then multiply by a factor of x10, just to be conservative.). I was the director of a major national toxicology laboratory for more than a decade. This is the way toxicologists think (I'm not formally trained as a toxicologist, BTW, I'm just an empirical experimental neuroscientist ).

Furthermore, the cancers that have been "strongly associated" with formaldehyde are "nasopharyngeal cancer, sinonasal cancer, and myeloid leukemia", so, unless you are snorting formaldehyde or being exposed to it in such quantities that you would see generalized effects like myeloid leukemia, I seriously doubt this is a real issue from vaping propylene glycol as any sane person here might do. Think about it, when was the last time you heard of an epidemic of 'smokers' dying of any of the mentioned cancers, and their formaldehyde inhalation is much, much greater than one might anticipate from even oxidizing propylene glycol in a vaping coil. In my opinion, cancer risk is the least of vapers' rationally-based fears.

 

[Teach]

Excellent comments mosspa. Thanks for the input!

 

[BigEgo]

Just came across this thread.

For someone new to vaping as myself it was interesting to find that vaping at a lower voltage VG-based juice would be a "healthier" option, well at least when it comes to carbonyls consumption.

Still not sure how voltage/wattage translates into temperatures. My sub ohm coil (0.6) produces tons of vaper at 2.8V (14W). Does it mean that it produces less carbonyls than a 2.0 coil at 4.8V (11.5W)? I guess both voltage and wattage readings are meaningless when only coil temperature matters.

Look forward to seeing more studies on temperatures and PEG.

It's more complicated than the authors of this paper made it sound. Of course, they probably know that, but it was beyond the scope of their research to elaborate on various coil builds and all that. Their experiment consisted of testing the device they had in front of them. The atomizer was a cheap clearomizer running on an ego Twist battery. It is called the "Crystal 2" and is a Vivi Nova (top coil) clearo sold in Poland. According to the paper, the coil resistance was 2.4 ohm. That's what they tested. The results of their tests should not be extrapolated to an RBA.

If you've ever vaped a Vivi Nova, you will know that running it much above the default 3.7 volts doesn't taste that great. By the time you get to 4.5v, it pretty much tastes awful. Why? Well, because #1, the tank's airflow is minimal and #2 the coil's heat flux is too high.

You can build a 2.4 ohm coil that will vape at a lower temperature, even if you put 5v to it. Stick it in an RBA with high airflow, and you wont get a crappy taste. The heat flux depends on the wire and coil diameters as well as how much wattage you put to it.

Instead of just telling us the voltage they ran the coil, a more accurate description would be to tell us the temperature of the coil during operation. Of course, this is no easy task.

Just because a cheap clearo releases carbonyls at 4.8v (10 watts) doesn't mean that a subohm build in an high airflow RDA running at 50 watts is going to do the same. Again, you have to take into account other variables.

But, if you want to vape as safely as possible and you use an ego twist and cheap clearos, then it is probably a good idea to stay at 4v or below. However, this study says nothing about RBA vaping. Dr. F. is supposed to be tackling that one soon.

 

[Robert Cromwell]

Good info. And why I stay low on volts and go with high VG. Maybe throat hits is a sign of a bad thing?

 

[Robert Cromwell]

Since reading this study I've gone from vaping at 4.1 volts to 3.3 volts on a 2 ohm atomiser. Better safe than sorry and to be honest it's still not a bad vape. Vape on

yeah. I went from higher PG to higher VG to reduce "throat hits". Anything that increases my tendency to cough cannot be better for me. I max out at 3.9 volts and use 80/20 VG/PG. Works great for me.

 

[rolygate]

PEG400 has been extensively used in ecig refills. Its main use was in prefilled cartos, as it presents flavours better than either PG or glycerine and was for a time part of the 'carto wars', where big brand mini ecig vendors tried to outdo each other for market share.

PEG stopped being used extensively because the cartos were all prefilled in China, and it was impossible to maintain quality control there. This was a problem because PEG is often contaminated with both DEG and EG (diethylene glycol and ethylene glycol) and these are toxic glycols (PG and PEG are harmless, DEG and others are toxic).

The original lab test the FDA did that identified DEG contamination, that was used extensively against us for years (2010 onward), identified DEG in a carto and this was almost certainly a PEG400 refill. (The 400 refers to the molecular weight and you can basically replace the text '400' with 'liquid'.) PEG comes in all forms from solid wax, through powder, to liquid. PEG is used extensively in medicines as an excipient or for its hygroscopic qualities. For example it is the principal ingredient in many laxatives, where - as 'Macrogol' - it accumulates water as a thick soup, travels through the gut, and then transfers that to a hard stool, releasing it as a result. Sorry about the TMI - just illustrating the fact it's a safe glycol, used extensively in medicines, just like PG.

The contamination of PEG has always been an issue as it is produced in the same facilities from the same feedstock as DEG. There have been numerous unpublicised incidents of contaminated PEG, which we know of. Indeed, this is one reason why we have factual evidence that Chinese manufacturing facilities, while having the highest quality of clean room manufacturing, have the lowest quality of customer care: if no purity standard or test certificates are specified for ecig refills due to incompetent contract standards by ignorant Western distributors, and if the FDA allow <2% DEG contamination, then you'll get around 2% DEG in your refills. Again, we have seen this.

In fact the FDA was formed in 1938 as a result of a major poisoning incident in 1937, when more than a hundred people were killed by a patent medicine that had DEG added to it; so the FDA do have some history with DEG.

PEG is fine when it can be supplied with guaranteed purity. One Chinese refill manufacturer has refused to supply PEG400 any more as it is impossible to guarantee purity. In practice this means it will be either expensive or impossible to obtain at a tested quality. If anyone offers you PEG, don't touch it unless you see a certificate for DEG and EG testing - from someone over here like Enthalpy Labs. A China test certificate may have about as much value as their standards of customer care.