# Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents



## Alex (20/3/17)

*A Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents*







Published: January 11, 2017
http://dx.doi.org/10.1371/journal.pone.0169811


*Abstract*
*Objectives*
To investigate how the two main electronic (e-) cigarette solvents—propylene glycol (PG) and glycerol (GL)—modulate the formation of toxic volatile carbonyl compounds under precisely controlled temperatures in the absence of nicotine and flavor additives.

*Methods*
PG, GL, PG:GL = 1:1 (wt/wt) mixture, and two commercial e-cigarette liquids were vaporized in a stainless steel, tubular reactor in flowing air ranging up to 318°C to simulate e-cigarette vaping. Aerosols were collected and analyzed to quantify the amount of volatile carbonyls produced with each of the five e-liquids.

*Results*
Significant amounts of formaldehyde and acetaldehyde were detected at reactor temperatures ≥215°C for both PG and GL. Acrolein was observed only in e-liquids containing GL when reactor temperatures exceeded 270°C. At 318°C, 2.03±0.80 μg of formaldehyde, 2.35±0.87 μg of acetaldehyde, and a trace amount of acetone were generated per milligram of PG; at the same temperature, 21.1±3.80 μg of formaldehyde, 2.40±0.99 μg of acetaldehyde, and 0.80±0.50 μg of acrolein were detected per milligram of GL.

*Conclusions*
We developed a device-independent test method to investigate carbonyl emissions from different e-cigarette liquids under precisely controlled temperatures. PG and GL were identified to be the main sources of toxic carbonyl compounds from e-cigarette use. GL produced much more formaldehyde than PG. Besides formaldehyde and acetaldehyde, measurable amounts of acrolein were also detected at ≥270°C but only when GL was present in the e-liquid. At 215°C, the estimated daily exposure to formaldehyde from e-cigarettes, exceeded United States Environmental Protection Agency (USEPA) and California Office of Environmental Health Hazard Assessment (OEHHA) acceptable limits, which emphasized the need to further examine the potential cancer and non-cancer health risks associated with e-cigarette use.

source: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169811

Presentation

Reactions: Thanks 2 | Informative 8


----------



## Andre (20/3/17)

Low power, high PG for the win!

Reactions: Like 1 | Agree 1


----------



## Rob Fisher (20/3/17)

Andre said:


> Low power, high PG for the win!



50/50 VM XXX at 26 watts. Drops mic.

Reactions: Like 5 | Funny 1


----------



## RichJB (20/3/17)

I guess that answers Dr F's question. Some time back, another study concluded that significant amounts of aldehydes were detected in vapour. He was puzzled because his testing didn't show any aldehydes. However, his testing was from several years ago when cigalikes running at 10W was the norm. So that was how he tested. He said he couldn't see any obviously flawed methodology in the newer test but would investigate further. It seems that the difference between Dr F's testing and Maciej Goniewicz's is simply that Maciej is running his test gear at the higher wattages and temps that today's 200W+ mods are capable of.

It remains to be seen how serious a problem these aldehydes are. It is accepted that it exceeds USEPA safe levels. But inhaling a fart would probably exceed USEPA's safe levels. That is not to say that the risk should be ignored, just that further analysis would be instructive. I wouldn't worry about the 318C results as that exceeds the top-end cutoff of today's TC devices. But 215C is well within the temp range of what most vapers find comfortable.

I guess the bottom line is to set your vape as cool as you can stand. I have always resisted the temptation to crank up the wattage and tried to stay around the 30W mark. I don't know how much it mitigates the risk but it doesn't hurt to be safe(r).

Now Maciej needs to crack on with his research on toxicants produced by flavourings. That is another area where I suspect the news won't be good. Please please please don't let there be anything bad in Butterscotch Ripple. Heh, as if FW would pass any test, lol.

Reactions: Like 3


----------



## Silver (20/3/17)

Thanks for sharing this @Alex 
Most interesting and lots of food for thought
I liked the video, very interesting.

Reactions: Agree 1 | Thanks 1


----------



## craigb (20/3/17)

So how does this compare to the quantity and severity of toxins in firsthand cigarette smoke? Normal, regular air?

It's good to be informed of the risks so that we can make and maintain informed decisions but I like to contextualise in terms of smoking and non smoking & non vaping.

Reactions: Agree 1


----------



## Feliks Karp (20/3/17)

craigb said:


> So how does this compare to the quantity and severity of toxins in firsthand cigarette smoke? Normal, regular air?
> 
> It's good to be informed of the risks so that we can make and maintain informed decisions but I like to contextualise in terms of smoking and non smoking & non vaping.



TLDR; 10 puffs of 270 degrees + looks to be the same amount of formaldehyde generated by a cigarette (considered to last 8-10 puffs).

Reactions: Thanks 1 | Informative 1


----------



## craigb (20/3/17)

Feliks Karp said:


> TLDR; 10 puffs of 270 degrees + looks to be the same amount of formaldehyde generated by a cigarette (considered to last 8-10 puffs).


So if this research stands (and I am not qualified to argue either way) then this is bloody scary, at least from the point of view of the toxins involved.

My average daily exposure to formaldehyde has therefore increased because I take more puffs on my vape than I did on stinkies. With max VG juice usually.

Realistically though, research still seems to point to vaping being healthier than smoking so results like this make me think a bit more about my life choices and realise that not inhaling foreign substances is the healthiest choice and everything beyond that is a trade off between pleasure and health.


----------



## Feliks Karp (20/3/17)

craigb said:


> So if this research stands (and I am not qualified to argue either way) then this is bloody scary, at least from the point of view of the toxins involved.
> 
> My average daily exposure to formaldehyde has therefore increased because I take more puffs on my vape than I did on stinkies. With max VG juice usually.
> 
> Realistically though, research still seems to point to vaping being healthier than smoking so results like this make me think a bit more about my life choices and realise that not inhaling foreign substances is the healthiest choice and everything beyond that is a trade off between pleasure and health.



The increase towards smoking levels of this toxin, is at high above average vaping temperatures or rather what the study suggests is the average temp (215degrees), the graph only starts climbing sharply after 215, and infact reaches more closely to cigarette levels at 300 degrees. ie: even high wattge vaping is safer than cigarettes, but this study suggests lower cooler vape would be considered more in line with acceptable exposure.

Reactions: Agree 1 | Thanks 1


----------



## Alex (20/3/17)

craigb said:


> So if this research stands (and I am not qualified to argue either way) then this is bloody scary, at least from the point of view of the toxins involved.
> 
> My average daily exposure to formaldehyde has therefore increased because I take more puffs on my vape than I did on stinkies. With max VG juice usually.
> 
> Realistically though, research still seems to point to vaping being healthier than smoking so results like this make me think a bit more about my life choices and realise that not inhaling foreign substances is the healthiest choice and everything beyond that is a trade off between pleasure and health.



My philosophy has always been to have the highest dose of nicotine required to satisfy the throat hit/craving, while using the least amount of liquid possible to achieve that goal.

ergo, higher nic -- lower wattage -- short drags --> lower temps.

Reactions: Like 3 | Agree 2


----------



## Silver (20/3/17)

craigb said:


> So if this research stands (and I am not qualified to argue either way) then this is bloody scary, at least from the point of view of the toxins involved.
> 
> My average daily exposure to formaldehyde has therefore increased because I take more puffs on my vape than I did on stinkies. With max VG juice usually.
> 
> Realistically though, research still seems to point to vaping being healthier than smoking so results like this make me think a bit more about my life choices and realise that not inhaling foreign substances is the healthiest choice and everything beyond that is a trade off between pleasure and health.



@craigb - what power and type of coils are you using?
And do you use temp control or plain power mode?


----------



## craigb (20/3/17)

Silver said:


> @craigb - what power and type of coils are you using?
> And do you use temp control or plain power mode?


Pico squeeze, so it's direct voltage running through 0.35ohm final resistance.

I like @Alex ''s way of doing things. Especially for those first in the morning hits.

Reactions: Like 1


----------



## Silver (20/3/17)

craigb said:


> Pico squeeze, so it's direct voltage running through 0.35ohm final resistance.
> 
> I like @Alex ''s way of doing things. Especially for those first in the morning hits.



Not sure what power you are running there - but the mech equivalent of a single battery 0.35 ohms is about 45 Watts. Depending on what wire and coils you are running and what airflow there is, that may get very hot or not get too hot. If its not getting too hot then I think this research is suggesting its all ok. 

I just have very little experience with temp control to know what temps I am vaping at. I would love to insert a temperature probe somehow into my RM2 and discover what temp my 29g paracoils are getting up to. Where is @Ezekiel ?

Reactions: Can relate 1


----------



## Raindance (20/3/17)

Running a 0.23 Ohm coil at 226 DegC restricts wattage to around 11 Watts when control temp has been reached. Vaping in Watt mode at wattage's over 11 thus heats the coil more than 226 degrees. Does this argument hold true or am I just tired?

Must say, a comparison of these results to stinky smoke would be pretty helpful. 

All in all I am a bit blue after hearing these results...

Regards


----------

