Electronic cigarettes (e-cigarettes) and other smokeless tobacco products are largely marketed as safer, cleaner alternatives to conventional smoked tobacco products. However, the use of these smokeless products, often referred to as “vaping”, presents its own set of concerns to human health and indoor air quality. How can just vapor cause so many problems? Well…
There’s more than one type of vapor
Merriam-Webster defines vapor as “diffused matter (such as smoke or fog) suspended floating in the air and impairing its transparency”.1 It says nothing about that matter needing to be water. E-cigarette liquid (e-liquid) typically contains a variety of chemicals, including glycerol and propylene glycol solvents, nicotine, and flavorings. When these chemicals are heated to the high temperatures needed for the solvents to vaporize, they can decompose into harmful byproducts, including formaldehyde, polycyclic aromatic hydrocarbons (PAHs), and fine particulate matter. Regulation of these e-cigarettes and their ingredients is still in its early stages. You can read more about the U.S. Food and Drug Administration’s (FDA) efforts here.
Vaping in the News
Recently, there has been a lot of attention directed at the use of e-cigarettes. Starting this past summer, there have been a string of reported illnesses, including multiple deaths, attributed to vaping. The exact cause of these cases of e-cigarette, or vaping, product use associated lung injury (EVALI)2 remains unclear. However, the CDC (Centers for Disease Control and Prevention) reports that there is a strong correlation between EVALI and the use of vaping products containing THC and vitamin E acetate. Although vitamin E acetate is safe for ingestion (eating and drinking), it seems to impair lung function when inhaled.
Another point of serious concern is the high (and growing) usage rate among adolescents. According to the
National Youth Tobacco Survey, over 20% of high school students reported using e-cigarettes in 2018.3 While these products might claim to wean existing smokers off of nicotine-containing products, E-cigarettes are spreading the threat of addition to a fresh population. This staggering trend has sparked efforts to reduce the availability of vaping products, particularly flavored e-liquids, which have been shown to appeal more to the younger demographic. In addition to the wide selection of flavors, these popular varieties often contain sweeteners.
Flavored e-liquid… it’s not so sweet
In a recent study, researchers at Portland State University led by Anna Duell examined the impact of sucralose, an artificial sweetener sometimes used to flavor e-liquids, on emissions from e-cigarettes. Sucralose is a major component of artificial sweeteners, such as Splenda, that are regularly consumed. However, just because something is safe to eat, doesn’t mean it’s safe to inhale. Sucralose starts to decompose (break down) into other compounds at 125 ⁰C. While 125 ⁰C is well above body temperature (~37 ⁰C), meaning sucralose will not decompose when eaten, it is below the temperature that e-liquids need to reach for vaping (~189-292 ⁰C). When sucralose breaks down, one of the products is acid. The researchers simulated vaping using a variety of different vaping coils (representing different devices) and e-liquids, varying the amount of sucralose. They then collected the aerosol emissions coming out of “puffs” from these coils and analyzed them for concentrations of different chemicals. They showed that this acid generation in turn causes more breakdown of the e-liquid solvents, and more emissions of harmful chemicals.
So, in short, while e-cigarettes contain less harmful substances than conventional cigarettes, they still emit harmful air-borne compounds… and more of these pollutants get released with e-liquids containing sucralose. The rapid rise in the popularity of vaping presents a growing source of indoor air pollution and health risks. As with conventional smoked tobacco products, the emissions from e-cigarettes impact more than just the user, secondhand smoke exposure can occur with e-cigarettes as well.
A. K. Duell, K. J. McWhirter, T. Korzun, R. M. Strongin, and D. H. Peyton. Sucralose-Enhanced Degradation of Electronic Cigarette Liquids during Vaping. Chem. Res. Toxicol. 32, 1241−1249 (2019). https://pubs.acs.org/doi/full/10.1021/acs.chemrestox.9b00047
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