The Impact of Device Settings, Use Patterns, and Flavorings on Carbonyl Emissions from Electronic Cigarettes

Abstract

Health impacts of electronic cigarette (e-cigarette) vaping are associated with the harmful chemicals emitted from e-cigarettes such as carbonyls. However, the levels of various carbonyl compounds under real-world vaping conditions have been understudied. This study evaluated the levels of carbonyl compounds (e.g., formaldehyde, acetaldehyde, glyoxal, and diacetyl, etc.) under various device settings (i.e., power output), vaping topographies, and e-liquid compositions (i.e., base liquid, flavor types). The results showed that e-vapor carbonyl levels were the highest under higher power outputs. The propylene glycol (PG)-based e-liquids generated higher formaldehyde and acetaldehyde than vegetable glycerin (VG)-based e-liquids. In addition, fruit flavored e-liquids (i.e., strawberry and dragon fruit) generated higher formaldehyde emissions than mint/menthol and creamy/sweet flavored e-liquids. While single-top coils formed 3.5-fold more formaldehyde per puff than conventional cigarette smoking, bottom coils generated 10–10,000 times less formaldehyde per puff. In general, increases in puff volume and longer puff durations generated significantly higher amounts of formaldehyde. While e-cigarettes emitted much lower levels of carbonyl compounds compared to conventional cigarettes, the presence of several toxic carbonyl compounds in e-cigarette vapor may still pose potential health risks for users without smoking history, including youth. Therefore, the public health administrations need to consider the vaping conditions which generated higher carbonyls, such as higher power output with PG e-liquid, when developing e-cigarette product standards.

Effects of Common e-Liquid Flavorants and Added Nicotine on Toxicant Formation during Vaping Analyzed by 1H NMR Spectroscopy

“…We found that benzaldehyde, vanillin, benzyl alcohol, and trans -cinnamaldehyde can enhance PG and GL degradation during vaping, consistent with other reports, including that e-liquids that contain greater concentrations of flavorants produce more HPHCs (as measured by carbonyl production). ,, We also found that nicotine inhibited the levels of HPHC formation in the presence of benzaldehyde, vanillin, benzyl alcohol, and a “flavorant mixture” when aerosolized, as compared to flavored e-liquids without nicotine. However, nicotine enhanced the levels of degradation when added to e-liquids with low and high concentrations of trans -cinnamaldehyde (39 and 155 mg/mL, respectively), as compared to the same e-liquids without nicotine.…”

Carbonyl Composition and Electrophilicity in Vaping Emissions of Flavored and Unflavored E-Liquids

“…Several carbonyls (formaldehyde, acetaldehyde, acetone, propionaldehyde, acrolein, glyoxal, methylglyoxal, and benzaldehyde) identified in this study are consistent to those reported previously [10,[49][50][51][52]. While formaldehyde, acetaldehyde, and acetone are common products of PG and VG degradation processes, productions of benzaldehyde and trans-2-hexenal are very likely linked to transformation of flavoring chemicals in e-liquids.…”

Kinetics of Aldehyde Flavorant-Acetal Formation in E-Liquids with Different E-Cigarette Solvents and Common Additives Studied by 1H NMR Spectroscopy

“…The addition of sweeteners (e.g., sucralose) and flavor enhancers (e.g., triacetin) to e-liquids can increase the degradation levels compared to e-liquids that are unsweetened and unflavored upon aerosolization as shown by Duell et al and Vreeke et al, respectively. The type of e-cigarette device, heating element, e-liquid composition, and use patterns the consumer employs can enhance the formation of HPHCs upon aerosolization.…”