The Chemical Complexity of e-Cigarette Aerosols Compared With the Smoke From a Tobacco Burning Cigarette

Abstract

Background: As e-cigarette popularity has increased, there is growing evidence to suggest that while they are highly likely to be considerably less harmful than cigarettes, their use is not free of risk to the user. There is therefore an ongoing need to characterise the chemical composition of e-cigarette aerosols, as a starting point in characterising risks associated with their use. This study examined the chemical complexity of aerosols generated by an e-cigarette containing one unflavored and three flavored e-liquids. A combination of targeted and untargeted chemical analysis approaches was used to examine the number of compounds comprising the aerosol. Contributions of e-liquid flavors to aerosol complexity were investigated, and the sources of other aerosol constituents sought. Emissions of 98 aerosol toxicants were quantified and compared to those in smoke from a reference tobacco cigarette generated under two different smoking regimes.Results: Combined untargeted and targeted aerosol analyses identified between 94 and 139 compounds in the flavored aerosols, compared with an estimated 72–79 in the unflavored aerosol. This is significantly less complex (by 1-2 orders of magnitude) than the reported composition of cigarette smoke. Combining both types of analysis identified 5–12 compounds over and above those found by untargeted analysis alone. Gravimetrically, 89–99% of the e-cigarette aerosol composition was composed of glycerol, propylene glycol, water and nicotine, and around 3% comprised other, more minor, constituents. Comparable data for the Ky3R4F reference tobacco cigarette pointed to 58–76% of cigarette smoke “tar” being composed of minor constituents. Levels of the targeted toxicants in the e-cigarette aerosols were significantly lower than those in cigarette smoke, with 68.5–>99% reductions under ISO 3308 puffing conditions and 88.4–>99% reductions under ISO 20778 (intense) conditions; reductions against the WHO TobReg 9 priority list were around 99%.Conclusion: These analyses showed that the e-cigarette aerosols contain fewer compounds and at significantly lower concentrations than cigarette smoke. The chemical diversity of an e-cigarette aerosol is strongly impacted by the choice of e-liquid ingredients.

Chemical characterisation of the vapour emitted by an e-cigarette using a ceramic wick-based technology

“…In our study, only acetaldehyde increased with the higher nicotine product (BB57); however, its concentration (0.10 µg puff -1 ) was still 160 times lower than the maximum level proposed by AFNOR (16 µg puff -1 ) 91 . A comparison of the emissions of an e-liquid with similar PG/VG ratio (1:1) emitted by a relatively similar Vype device (ePen) that uses a silica wick showed that formaldehyde at a concentration of 0.59 µg puff -1 was 8× higher and acetaldehyde at a concentration of 0.18 µg puff -1 was 2× higher than in the emissions presented herein (Table 3) 92 . In both studies, the values were below the maximum level proposed by AFNOR 91 .…”

The Effects of E-Cigarette Aerosol on Oral Cavity Cells and Tissues: A Narrative Review

“…It can be suggested that falvoring chemicals and nicotine play an important role in the production of ROS [39][40][41], and the amount and proportions vary from product to product [42]. Nevertheless, the studies also showed that the levels of free radicals are lower in e-fluid and the gas phase of aerosol and heat-not-burn products compared to traditional cigarettes, and contain fewer toxic substances at lower concentrations [43]. An exposure of tissues to free radicals can result in damage to the proliferation, survival and inflammation pathways in cells [36].…”

Emission and Gas/Particle Partitioning Characteristics of Nicotine in Aerosols for Electronic Cigarettes

“…As a result of no high-temperature combustion phenomenon, the heating temperatures of electronic cigarettes are much lower than those of the burning cigarettes. The electronic cigarettes could reduce the complexities and concentrations of harmful chemicals in aerosols compared with the traditional cigarettes . It substantially reduces smokers’ exposures to the toxic substances. , The effects of harm reduction brought by electronic cigarettes are effective. − The success rates of smoking cessation through the use of electronic cigarettes are nearly twice that of nicotine replacement therapy, such as nicotine patches and nicotine gum .…”

“…The electronic cigarettes could reduce the complexities and concentrations of harmful chemicals in aerosols compared with the traditional cigarettes. 1 It substantially reduces smokers' exposures to the toxic substances. 2,3 The effects of harm reduction brought by electronic cigarettes are effective.…”