There is interest in the relative toxicities of emissions from electronic cigarettes and tobacco cigarettes. Lists of cigarette smoke priority toxicants have been developed to focus regulatory initiatives. However, a comprehensive assessment of e-cigarette chemical emissions including all tobacco smoke Harmful and Potentially Harmful Constituents, and additional toxic species reportedly present in e-cigarette emissions, is lacking. We examined 150 chemical emissions from an e-cigarette (Vype ePen), a reference tobacco cigarette (Ky3R4F), and laboratory air/method blanks. All measurements were conducted by a contract research laboratory using ISO 17025 accredited methods. The data show that it is essential to conduct laboratory air/method measurements when measuring e-cigarette emissions, owing to the combination of low emissions and the associated impact of laboratory background that can lead to false-positive results and overestimates. Of the 150 measurands examined in the e-cigarette aerosol, 104 were not detected and 21 were present due to laboratory background. Of the 25 detected aerosol constituents, 9 were present at levels too low to be quantified and 16 were generated in whole or in part by the e-cigarette. These comprised major e-liquid constituents (nicotine, propylene glycol, and glycerol), recognized impurities in Pharmacopoeia-quality nicotine, and eight thermal decomposition products of propylene glycol or glycerol. By contrast, approximately 100 measurands were detected in mainstream cigarette smoke. Depending on the regulatory list considered and the puffing regime used, the emissions of toxicants identified for regulation were from 82 to >99% lower on a per-puff basis from the e-cigarette compared with those from Ky3R4F. Thus, the aerosol from the e-cigarette is compositionally less complex than cigarette smoke and contains significantly lower levels of toxicants. These data demonstrate that e-cigarettes can be developed that offer the potential for substantially reduced exposure to cigarette toxicants. Further studies are required to establish whether the potential lower consumer exposure to these toxicants will result in tangible public health benefits.
For a tobacco heating product (THP), which heats rather than burns tobacco, the emissions of toxicants in the aerosol were compared with those in cigarette smoke under a machine-puffing regimen of puff volume 55 ml, puff duration 2 s and puff interval 30 s. The list of toxicants included those proposed by Health Canada, the World Health Organization Study Group on Tobacco Product Regulation (TobReg), the US Food and Drug Administration and possible thermal breakdown products. In comparison to the University of Kentucky 3R4F reference cigarette the toxicant levels in the THP1.0 emissions were significantly reduced across all chemical classes. For the nine toxicants proposed by TobReg for mandated reduction in cigarette emissions, the mean reductions in THP1.0 aerosol were 90.6-99.9% per consumable with an overall average reduction of 97.1%. For the abbreviated list of harmful and potentially harmful constituents of smoke specified by the US Food and Drug Administration Tobacco Products Scientific Advisory Committee for reporting in cigarette smoke (excluding nicotine), reductions in the aerosol of THP1.0 were 84.6-99.9% per consumable with an overall average reduction of 97.5%.
The thermal decomposition of two tobacco blends was studied by thermogravimetry -mass spectrometry (TGA-MS) at slow heating programs under well defined conditions. The kinetic evaluation was based on a distributed activation energy model (DAEM) which is a suitable tool for complex materials of plant origin. Linear and non-linear (stepwise) heating programs were employed to obtain information for reliable kinetic modeling. Series of experiments were evaluated simultaneously by the method of least squares. Efforts were made to identify and describe kinetically the similarities between two, highly different tobacco samples as well as between the various mass spectrometric intensity curves.This was achieved by evaluating large series of experimental results and assuming several kinetic parameters to be common for both samples and/or a group of mass spectrometric intensities. (4) and (5)) cnormed,j cj coefficients normalized so that their sum equals to one (see Eq. (8)) E0,j mean activation energy in a distributed activation energy model (kJ mol -1 )FWHM full width at half maximum (°C) fitN a measure of the fit quality that expresses the difference between a group of N experimental curves and their simulated counterparts (%) (See Eqs. (5) and (6)
A novel tobacco heating product, THP1.0, that heats tobacco below 245 °C is described. It was designed to eliminate tobacco combustion, while heating tobacco to release nicotine, tobacco volatiles and glycerol to form its aerosol. The stewardship assessment approach behind the THP 1.0 design was based on established toxicological principles. Thermophysical studies were conducted to examine the extent of tobacco thermal conversion during operation. Thermogravimetric analysis of the tobacco material revealed the major thermal behaviour in air and nitrogen up to 900 °C. This, combined with the heating temperature profiling of the heater and tobacco rod, verified that the tobacco was not subject to combustion. The levels of tobacco combustion markers (CO, CO, NO and NO) in the aerosol of THP1.0 were significantly lower than the levels if there were any significant pyrolysis or combustion. Quantification of other tobacco thermal decomposition and evaporative transfer markers showed that these levels were, on average, reduced by more than 90% in THP1.0 aerosol as compared with cigarette smoke. The physical integrity of the tobacco consumable rod showed no ashing. Taken together, these data establish that the aerosol generated by THP1.0 is produced mainly by evaporation and distillation, and not by combustion or pyrolysis.
a b s t r a c tThere is a drive toward the mandated lowering and reporting of selected toxicants in tobacco smoke. Several studies have quantified the mainstream cigarette emissions of toxicants, providing benchmark levels. Few, however, have examined how measured toxicant levels within a single product vary over time due to natural variation in the tobacco, manufacturing and measurement. In a single centre analysis, key toxicants were measured in the tobacco blend and smoke of 3R4F reference cigarette and three commercial products, each sampled monthly for 10 months. For most analytes, monthly variation was low (coefficient of variation <15%); but higher (P20%) for some compounds present at low (ppb) levels. Reporting toxicant emissions as a ratio to nicotine increased the monthly variation of the 9 analytes proposed for mandated lowering, by 1-2 percentage points. Variation in toxicant levels was generally 1.5-1.7-fold higher in commercial cigarettes compared with 3R4F over the 10-month period, but increased up to 3.5-fold for analytes measured at ppb level. The potential error (2CV) associated with single-point-intime sampling averaged $20%. Together, these data demonstrate that measurement of emissions from commercial cigarettes is associated with considerable variation for low-level toxicants. This variation would increase if the analyses were conducted in more than one laboratory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.