E-cigarette usage in recent years has grown rapidly with 12.6% of adults in 2014 having reported using them at least once. The largest group of users are those aged 18-24 and nearly 3% of the people who have ever tried e-cigarettes were not smokers before trying them. More frighteningly, from 2013 to 2014 the number of high school students in the US using e-cigarettes has tripled from 1.1% to 3.9% (120,000 to 450,000). Many people use e-cigarettes to lower or stop their dependency on harmful cigarettes or to get their nicotine fix in places where smoking is not allowed. E-cigarettes typically are powered by a rechargeable battery that powers a heating coil to vaporize the e-liquid that the user adds. The e-liquids contain nicotine, favorings and either propylene glycol or vegetable glycerin (or a mix of the two). All these compounds have been approved as safe for human consumption but a problem arises when they are rapidly heated and vaporized. During this rapid heating, the chemicals in e-liquids can be changed into other more harmful compounds. A research group based in California sought out to characterize and understand what happens to e-liquids when they are heated and vaporized.
The team used two types of e-cigarettes: the eGO CE4, a small cheap model with one heating coil, and the Kangertech Aerotank Mini, a larger mode with two heating coils. They also tested out 3 flavours of e-liquids: Classic Tobacco, Bubblicious, Mojito Mix. They analyzed the components of the vapour released by both e-cigarettes and also analyzed what happened to the composition of that vapour over different voltages, number of puffs, and age of the device.
Composition of e-cigarette vapour: The vapour consisted of a number of glycerol and glycol breakdown products including: acrolein, acetaldehyde, formaldehyde, nicotyrine, glycidol, propylene oxide, and diacetyl. Acrolein is a known irritant of the skin, eyes, and airways that can cause local inflammation. Formaldehyde is toxic and deadly at high enough doses and is a known carcinogen following prolonged exposure. Glycidol, acetaldehyde and, propylene oxide are both known carcinogens. The researchers found that initially both e-cigarettes generated similar levels of each compound. When the device was running for a while the levels of all compounds in the vapour increased.
Effect of temperature: E-cigarettes let you control the temperature (and therefore degree of vaporization) by changing the voltage of the heating coil. As the voltage was increased, there was a substantial increase in the amount of toxic compounds released. At the highest voltage tested (4.8 Volts) there was twice as much formaldehyde released compared to the lowest setting and the amount of acetaldehyde and acrolein greatly increased.
Age of the device: To test the effect of aging on the device, the researchers subjected the eGO vaporizer to 50 consecutive puffs nine times in a row (for a total of 450 puffs). They found that by the end of the cycle, there was 1.5 times more toxic chemicals released by the e-cigarette compared to the first cycle of puffs. This included 2x more formaldehyde and 1.5x more acrolin and acetaldehyde.
Finally, the researchers were also able to tell that the majority of the compounds came from the solvents in the e-liquid, propylene glycol and glycerin. They determined this by heating solutions of just the solvents and found that the chemicals released by the vapours were similar to the ones released by the e-liquids.
This research is important because there is a growing number of young people who have started using e-cigarettes and there is a fear that this trend could be the next wave in the battle against tobacco companies. With flavours such as bubble gum and fruit punch, e-cigarettes easily attract young people in a way that sweet alcoholic drinks do. E-cigarettes are often seen as a better alternative to traditional cigarettes and while this is true, it is not the same as saying they are safe. E-cigarettes are harmful and as the vaping trend continues to get more popular it wont be long the negative consequences manifesting themselves as disease epidemics. We need to stop pretending these devices are harmless and regulate them. They are not just ‘water vaporizers’ they contain compounds that when heated rapidly can produce harmful irritants and carcinogens.
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