
The study, which was published in Environmental Science & Technology, found that the thermal decomposition of propylene glycol and glycerin, two solvents found in most "e-liquids" (the substance that is vaporized by the e-cigarette), leads to emissions of toxic chemicals such as acrolein and formaldehyde.
"Advocates of e-cigarettes say emissions are much lower than from conventional cigarettes, so you're better off using e-cigarettes," said Berkeley Lab researcher and the study's corresponding author Hugo Destaillats. "I would say, that may be true for certain users--for example, long time smokers that cannot quit--but the problem is, it doesn't mean that they're healthy. Regular cigarettes are super unhealthy. E-cigarettes are just unhealthy."
Comment: Contrary to popular belief, researchers have consistently failed to prove that smoking tobacco is the cause of any of the diseases it is associated with. In fact, smoking has actually been shown to significantly increase longevity, mitochondrial function, cognition, attention, motor skills, and memory. Numerous studies have also found an inverse association with numerous diseases including lung cancer, Alzheimers, Parkinsons, and ulcerative colitis (to name a few). For more information on the health benefits of smoking tobacco, see the following:
- The Health & Wellness Show: The Truth about Tobacco and the Benefits of Nicotine
- The Health & Wellness Show: The Truth about Tobacco and the Benefits of Nicotine - Part 2
- The epidemic of junk science in tobacco smoking research
- The oldest people on Earth are all smokers!
- The myth of smoking during pregnancy being harmful
- 5 Health Benefits of Smoking
- Let's All Light Up!
- Nicotine - The Zombie Antidote
In the paper, "Emissions from electronic cigarettes: Key parameters affecting the release of harmful chemicals," Destaillats and a team of researchers simulated vaping using three types of e-liquids in two different vaporizers operated at various battery power settings. The two e-cigarettes were quite different, one fairly cheap with one heating coil, the other more expensive with two heating coils in parallel. The researchers used gas and liquid chromatography to determine what was in the vapor, looking at the first puffs as well as later puffs after the device heated up and reached a "steady state."
Not all puffs are equal
One finding was that the first and last puffs produce widely varying emissions. Using a custom-built vaping apparatus emulating realistic vaping habits, researchers drew on the e-cigarette by taking puffs lasting 5 seconds every 30 seconds. They found that vapor temperature rose quickly in the first 5 to 10 minutes until reaching a steady state temperature at around the twentieth puff.
Correspondingly, emissions levels between the first few puffs and the steady state increased by a factor of 10 or more in some cases, depending on the device, the battery voltage, and the emitted compound. For example, for acrolein, a severe eye and respiratory irritant, a single-coil e-cigarette operated at 3.8 volts emitted 0.46 micrograms per puff in the first five puffs, but at the steady state it emitted 8.7 micrograms per puff. "When you apply the same voltage to the double-coil e-cigarette you see a lot less emissions," said co-author and Berkeley Lab researcher Lara Gundel. "We think it has to do with lower temperatures at each of the coil surfaces."
For comparison, conventional cigarettes emit 400 to 650 micrograms of acrolein per cigarette, accounting for both mainstream and sidestream emissions. Assuming 20 puffs on an e-cigarette is equivalent to smoking a conventional cigarette, Gundel said, then total emissions of acrolein for an e-cigarette are about 90 to 100 micrograms.
Separately, to test effects due to device aging, researchers used a single device over nine consecutive 50-puff cycles without cleaning. Again, emissions of formaldehyde, acetaldehyde, and acrolein--all either carcinogens or respiratory irritants--increased with usage. "In some cases we saw aldehyde levels increase 60 percent between cycles 1 and 9," said co-author and Berkeley Lab researcher Mohamad Sleiman.
The researchers note in their paper: "This effect is consistent with the buildup of polymerization byproducts on or near the coil leading to accumulation of the sort of residues that are often referred to in the blogosphere as 'coil gunk' or 'caramelization.' Heating these residues would provide a secondary source of volatile aldehydes."
Lastly, because many e-cigarettes allow users to control the voltage, the researchers systematically investigated the effect of voltage on emissions. They found that as the voltage increased, both the amount of e-liquid consumed per puff and the vapor temperature were higher. In the case of acrolein and formaldehyde, the amount formed at the highest voltage of 4.8V was an order of magnitude higher than the amount at the lowest voltage of 3.3V.
Destaillats takes pains to note that the results do not mean that e-cigarettes are safe to use at lower temperatures. "We found there are emissions of toxic chemicals at any temperature at which you use the device," he said. "And the higher the temperature, the more emissions."
Two new carcinogens detected
Because there is an immense variety of e-cigarettes as well as e-liquids, the Berkeley Lab researchers decided to focus on an element that is common to all of them: the solvent in the e-liquid. Almost all e-liquids use a combination of propylene glycol and glycerin in varying proportions as a solvent.
"Both are used for making artificial smoke on stage," Destaillats said. "The ratio between the two determines things like the volume of vapor cloud that you produce. They are considered safe for food."
However, there have been few if any studies on the safety of heating and inhaling propylene glycol and glycerin. "People are not drinking the liquids--they're vaping them," said Sleiman. "So what counts is the vapor."
The researchers vaporized liquids consisting solely of the solvents to verify that they were the source of the emissions. In all, the researchers detected significant levels of 31 harmful chemical compounds, including two that had never been previously found in e-cigarette vapor--propylene oxide and glycidol, both of which are probable carcinogens.
"Understanding how these compounds are formed is very important," Destaillats said. "One reason is for regulatory purposes, and the second is, if you want to manufacture a less harmful e-cigarette, you have to understand what the main sources of these carcinogens are."
Story Source:
The above post is reprinted from materials provided by DOE/Lawrence Berkeley National Laboratory. Note: Materials may be edited for content and length.
Journal Reference:
- Mohamad Sleiman, Jennifer M. Logue, V. Nahuel Montesinos, Marion L. Russell, Marta I. Litter, Lara A. Gundel, Hugo Destaillats. Emissions from Electronic Cigarettes: Key Parameters Affecting the Release of Harmful Chemicals. Environmental Science & Technology, 2016; DOI:10.1021/acs.est.6b01741
Reader Comments
Give me a break please.... the results from this testing show acrolein levels, even at the 'high end' less than ONE FIFTIETH that of a traditional cigarette and notice they didn't even mention the levels of aldehydes? I have a feeling because it was barely significant in measure. The last thing the cigarette companies and governments who profit MASSIVELY off the taxes of tobacco want, is a viable alternative to cigarettes for smokers to turn to in an attempt to either quit or reduce harm.
As for Treedirt above, get off your high horse... the pollutants in these things and cigarettes for that matter, pale in relative comparison to regular pollution that's floating aaallll around you unless you're in the middle of the forest, hundreds of miles from civilization. As long as you're not locked in a box with somebody huffing away, the tiny trace amounts you're exposed to in open air are beyond negligible. PERFUME is probably worse on the pollution scale but you don't see that being demonized do you? Heck, I'll bet huge money the atmosphere in your house/apartment is worse for you from the cleansers and off gassing of the various belongings you possess... look it up, it might shock you how bad the average living accommodation's air quality is.
i could care less what people put in their lungs but the e-cig morons love to take these enormous hits and then literally fill up about a 5 foot radius of where they are. I don't give two shits about what your doing but i certainly do not wanna share with you all the crap coming out of your lungs.