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2.
Tob Control ; 31(5): 667-670, 2022 09.
Article in English | MEDLINE | ID: mdl-33980722

ABSTRACT

INTRODUCTION: Use of flavoured pod-mod-like disposable electronic cigarettes (e-cigarettes) has grown rapidly, particularly among cost-sensitive youth and young adults. To date, little is known about their design characteristics and toxicant emissions. In this study, we analysed the electrical and chemical characteristics and nicotine and pulmonary toxicant emission profiles of five commonly available flavoured disposable e-cigarettes and compared these data with those of a JUUL, a cartridge-based e-cigarette device that pod-mod-like disposables emulate in size and shape. METHODS: Device construction, electrical power and liquid composition were determined. Machine-generated aerosol emissions including particulate matter, nicotine, carbonyl compounds and heavy metals were also measured. Liquid and aerosol composition were measured by high-performance liquid chromatography, gas chromatography-mass spectrometry/flame ionisation detection, and inductively coupled plasma mass spectrometry. RESULTS: We found that unlike JUUL, disposable devices did not incorporate a microcontroller to regulate electrical power to the heating coil. Quality of construction varied widely. Disposable e-cigarette power ranged between 5 and 9 W and liquid nicotine concentration ranged between 53 and 85 mg/mL (~95% in the protonated form). In 15 puffs, total nicotine yield for the disposables ranged between 1.6 and 6.7 mg, total carbonyls ranged between 28 and 138 µg, and total metals ranged between 1084 and 5804 ng. JUUL emissions were near the floors of all of these ranges. CONCLUSIONS: Disposable e-cigarettes are designed with high nicotine concentration liquids and are capable of emitting much higher nicotine and carbonyl species relative to rechargeable look-alike e-cigarettes. These differences are likely due to the lower quality in construction, unreliable labelling and lack of temperature control regulation that limits the power during operation. From a public health perspective, regulating these devices is important to limit user exposure to carbonyls and nicotine, particularly because these devices are popular with youth and young adults.


Subject(s)
Electronic Nicotine Delivery Systems , Tobacco Products , Vaping , Adolescent , Aerosols , Flavoring Agents/analysis , Hazardous Substances , Humans , Nicotine/analysis , Young Adult
3.
Chem Res Toxicol ; 34(6): 1572-1577, 2021 06 21.
Article in English | MEDLINE | ID: mdl-33945261

ABSTRACT

In late 2019, hundreds of users of electronic products that aerosolize a liquid for inhalation were hospitalized with a variety of respiratory and gastrointestinal symptoms. While some investigations have attributed the disease to the presence of vitamin E acetate in liquids that also contained tetrahydrocannabinol, some evidence suggests that chronic inhalation of two common solvents used in electronic nicotine delivery systems (ENDS), propylene glycol (PG) and vegetable glycerin (VG), can interfere with the lipid components of pulmonary surfactant and cause or exacerbate pulmonary injury. The interaction between PG, VG, and lung surfactant is not yet understood. This study presents an examination of the molecular interactions of PG and VG with lung surfactant mimicked by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The interaction of DPPC and PG-VG is studied by attenuated total reflectance fourier transform infrared spectroscopy. The results showed that PG and VG altered the molecular alignment of the DPPC surfactant. The orientation of the surfactant at the surface of the lung affects the surface tension at the air-water interface, thereby influencing breathing. These findings suggest that chronic aerosolization of the primary solvents in ENDS might alter the function of pulmonary surfactant.


Subject(s)
Drug Delivery Systems , Electronic Nicotine Delivery Systems , Pulmonary Surfactants/chemistry , Solvents/chemistry
4.
Tob Control ; 2021 May 07.
Article in English | MEDLINE | ID: mdl-33963073

ABSTRACT

In 2019, JUUL Labs began marketing in the European Union 'new technology' pods that incorporated a new wick that it claimed provided 'more satisfaction'. In this study, we compared design and materials of construction, electrical characteristics, liquid composition and nicotine and carbonyl emissions of new technology JUUL pods to their predecessors. Consistent with manufacturer's claims, we found that the new pods incorporated a different wicking material. However, we also found that the new pod design resulted in 50% greater nicotine emissions per puff than its predecessor, despite exhibiting unchanged liquid composition, device geometry and heating coil resistance. We found that when connected to the new technology pods, the JUUL power unit delivered a more consistent voltage to the heating coil. This behaviour suggests that the new coil-wick system resulted in better surface contact between the liquid and the temperature-regulated heating coil. Total carbonyl emissions did not differ across pod generations. That nicotine yields can be greatly altered with a simple substitution of wick material underscores the fragility of regulatory approaches that centre on product design rather than product performance specifications.

5.
Tob Control ; 30(3): 348-350, 2021 05.
Article in English | MEDLINE | ID: mdl-32522818

ABSTRACT

Some jurisdictions have instituted limits on electronic cigarette (ECIG) liquid nicotine concentration, in an effort to control ECIG nicotine yield, and others are considering following suit. Because ECIG nicotine yield is proportional to the product of liquid nicotine concentration (milligram per millilitre) and device power (watts) regulations that limit liquid nicotine concentration may drive users to adopt higher wattage devices to obtain a desired nicotine yield. In this study we investigated, under various hypothetical regulatory limits on ECIG liquid nicotine concentration, a scenario in which a user of a common ECIG device (SMOK TF-N2) seeks to obtain in 15 puffs the nicotine emissions equivalent to one combustible cigarette (ie, 1.8 mg). We measured total aerosol and carbonyl compound (CC) yields in 15 puffs as a function of power (15-80 W) while all else was held constant. The estimated nicotine concentration needed to achieve combustible cigarette-like nicotine yield at each power level was then computed based on the measured liquid consumption. We found that for a constant nicotine yield of 1.8 mg, reducing the liquid nicotine concentration resulted in greater amount of liquid aerosolised (p<0.01) and greater CC emissions (p<0.05). Thus, if users seek a given nicotine yield, regulatory limits on nicotine concentration may have the unintended consequence of increasing exposure to aerosol and respiratory toxicants. This outcome demonstrates that attempting to control ECIG nicotine yield by regulating one factor at a time may have unintended health effects and highlights the need to consider multiple factors and outcomes simultaneously when designing regulations.


Subject(s)
Electronic Nicotine Delivery Systems , Aerosols , Hazardous Substances , Humans , Nicotine
6.
Chem Res Toxicol ; 2020 Jul 22.
Article in English | MEDLINE | ID: mdl-32635721

ABSTRACT

Electronic cigarettes (ECIGs) are a class of tobacco products that emit a nicotine-containing aerosol by heating and vaporizing a liquid. Apart from initiating nicotine addiction in nonsmokers, a persistent concern about these products is that their emissions often include high levels of carbonyl species, toxicants thought to cause most noncancer pulmonary diseases in smokers. This study examined whether the phenomenon of film boiling can account for observations of high carbonyl emissions under certain operating conditions and, if so, whether film boiling theory can be invoked to predict conditions where high carbonyl emissions are likely. We measured the critical heat flux for several common heating materials and liquids and carbonyl emissions for several ECIG types while varying the power. We found that emissions rise drastically whenever the power exceeds the value corresponding to the critical heat flux. While limiting the heat flux to below this threshold can greatly reduce carbonyl exposure, ECIG manufacturer operating instructions often exceed it. Product regulations that limit heat flux may reduce the public health burden of electronic cigarette use.

7.
Sci Rep ; 10(1): 7322, 2020 04 30.
Article in English | MEDLINE | ID: mdl-32355323

ABSTRACT

In 2018, JUUL entered the UK market, where EU regulations limit liquid nicotine concentration to 20 mg/mL, approximately one-third the level of JUUL products sold in the USA. We hypothesized that JUUL's UK product was engineered to deliver greater electrical power and boost liquid vaporization such that the net nicotine delivery rate was similar to the US version. We compared electrical characteristics, liquid composition, and aerosol emissions of JUUL devices procured in the USA and the UK. Study outcomes included electrical power, total and freebase nicotine, propylene glycol/vegetable glycerin ratio, carbonyls, and reactive oxygen species. Liquids and aerosols were analyzed by GCMS, HPLC, and fluorescence. Compared to the US version, JUUL UK had approximately one-third the liquid nicotine concentration in the liquid (5.4 vs. 1.6 wt.%) and aerosol (4.7 and 1.3 wt.%). Other than nicotine concentration and yield, we found no differences in any other study outcome, including electrical power. Currently, JUUL UK emits nicotine at a far lower rate than the US product, offering an opportunity to study how this factor impacts user behavior, JUUL uptake, and other population-level outcomes across the two markets.


Subject(s)
Electronic Nicotine Delivery Systems , Nicotine/analysis , Aerosols , Electricity , Flavoring Agents/analysis , Glycerol/analysis , Hydrogen-Ion Concentration , Propylene Glycol/analysis , Reactive Oxygen Species/analysis , United Kingdom , United States , Vaping
8.
Chem Res Toxicol ; 32(6): 1235-1240, 2019 06 17.
Article in English | MEDLINE | ID: mdl-31038931

ABSTRACT

Waterpipe tobacco smoking (WTS) has been characterized as a global epidemic. Waterpipe smoke has been shown to contain and deliver significant doses of many of the toxicants known to cause cancer, respiratory, and cardiovascular diseases in cigarette smokers. It has also been shown that the charcoal used to heat the tobacco contributes most of the polycyclic aromatic hydrocarbons (PAHs) and carbon monoxide (CO) found in the smoke, two major causative agents in smoking-related lung cancer and heart disease, respectively. Possibly as a result of growing awareness of charcoal as a toxicant source, electrical heating elements (EHEs) are being marketed for waterpipe use as reduced harm charcoal substitutes. We measured thermal performance characteristics (tobacco burned, total aerosolized particulate matter) and toxicant emissions in WTS generated using three commercially available waterpipe EHEs and charcoal to examine the hypothesis that EHEs can function similarly to charcoal while presenting a reduced toxicant profile. Toxicants quantified included total particulate matter, nicotine, PAHs, CO, and volatile aldehydes delivered at the mouthpiece when the waterpipe was machine smoked using a standard protocol. We found that while EHEs involved an 80% reduction in total PAH and a 90% reduction in CO emissions, they also resulted in a several-fold increase in the potent respiratory toxicant acrolein. These mixed findings underscore the complexity of toxicant reduction by product manipulation and suggest that marketing EHEs as reduced harm products may be misleading.


Subject(s)
Aldehydes/analysis , Carbon Monoxide/analysis , Charcoal/chemistry , Electricity , Heating , Polycyclic Aromatic Hydrocarbons/analysis , Tobacco Smoke Pollution/analysis , Tobacco Smoking , Tobacco, Waterpipe/analysis , Humans
9.
Tob Control ; 28(6): 678-680, 2019 11.
Article in English | MEDLINE | ID: mdl-30745326

ABSTRACT

INTRODUCTION: JUUL is an electronic cigarette (ECIG) with a compact form factor. It is prefilled with a liquid that is advertised to contain a high concentration of nicotine salt. JUUL commands 50% of the US ECIG market share, and its wide popularity with underage users has triggered unprecedented actions by the US FDA. Apart from its nicotine salt-containing liquid and compact form, a salient advertised design feature is a control circuit that limits the heating coil temperature, presumably reducing unwanted toxicants. In this study, several tobacco-flavoured JUUL devices were reverse engineered, and their aerosol emissions were studied. METHODS: Total nicotine and its partitioning (freebase and protonated), propylene glycol/vegetable glycerin (PG/VG) ratio, and carbonyls were quantified by gas chromatography (GC) and high performance liquid chromatography (HPLC). The temperature control functionality of JUUL was investigated using a temperature-controlled bath in which the coil was submerged. RESULTS: The liquid nicotine concentration was found to be 69 mg/mL, and the liquid and aerosol PG/VG ratio was found to be 30/70. In 15 puffs, JUUL emitted 2.05 (0.08) mg of nicotine, overwhelmingly in the protonated form. Carbonyl yields were significantly lower than those reported for combustible cigarettes, but similar to other closed-system ECIG devices. The heating coil resistance was 1.6 (0.66) Ohm, while the maximum power delivered by the JUUL device was 8.1 W. The control circuit limited the peak operating temperature to approximately 215C. CONCLUSIONS: JUUL emits a high-nicotine concentration aerosol predominantly in the protonated form. JUUL's nicotine-normalised formaldehyde and total aldehyde yields are lower than other previously studied ECIGs and combustible cigarettes.


Subject(s)
Electronic Nicotine Delivery Systems , Formaldehyde , Glycerol/analysis , Inhalation Exposure , Nicotine , Propylene Glycol/analysis , Vaping , Carcinogens/analysis , Chromatography, Gas/methods , Chromatography, Liquid/methods , Flavoring Agents/adverse effects , Flavoring Agents/analysis , Formaldehyde/adverse effects , Formaldehyde/analysis , Humans , Inhalation Exposure/adverse effects , Inhalation Exposure/analysis , Inhalation Exposure/prevention & control , Nicotine/adverse effects , Nicotine/analysis , Solvents/analysis , Vaping/adverse effects , Vaping/epidemiology , Vaping/prevention & control
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