Public Health Consequences of E-Cigarettes (2018) / Chapter Skim
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3 E-Cigarette Devices, Uses, and Exposures
3 E-Cigarette Devices, Uses, and Exposures
Pages 55-88
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From page 55... ...
The basic operation of e-cigarettes generally follows several steps and includes drawing on the e-cigarette, activation of a heating element, which aerosolizes the contained liquid, and inhalation of the liquid aerosol. Currently, a diverse and non-standardized terminology is used to refer to e-cigarette devices, their components, and their use.
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From page 56... ...
Chapter 5 presents a comprehensive discussion on the toxicology of e-liquid constituents and other contaminants found in e-cigarette aerosols. The battery design and type may put the device at risk for a fire or in rare cases for an explosion, and in combination with the heating coils, the battery also influences the aerosol properties (discussed in more detail in the following paragraph)
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From page 57... ...
or "vape sticks." Other cigalikes are slightly longer or narrower than a combustible tobacco cigarette (so called "pen style")
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From page 58... ...
The pharmacology and toxicology of those exposures is discussed in Chapters 4 and 5. Puff Topography For combustible tobacco cigarettes, smoking is understood to be a complex process that allows smokers to titrate their desired dose of nicotine and nicotine brain level on a puff-by-puff basis.
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From page 59... ...
Norton and colleagues (2014) conducted a pilot study to examine initial reactions to e-cigarette use and puffing behaviors among combustible tobacco cigarette smokers.
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From page 60... ...
(ad lib) Usual n/a Lab; 1 combustible cigarette tobacco cigarette Farsalinos et eVic by 18 mg/ml E-cigarette– Lab; 10 puffs eVic al., 2015a Joyetech naïve, in 5 minutes (2nd combustible followed by generation)
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From page 61... ...
67.5 (SE = 6.3) n/a E-cigarette– n/a n/a n/a naïve, combustible tobacco smokers: 2.3 (SE = 0.2)
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From page 62... ...
Cloud: 23–24 mg Usual n/a Lab; 1 combustible cigarette tobacco (day 1) cigarette Goniewicz Usual n/a 10 Lab; ad lib CReSS et al., 2013 e-cigarette brands Behar et al., blu and blu: 16 mg/ 20 Lab; ad lib CReSS 2015 V2 (1st ml; V2: 18 use for 10 generation)
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From page 63... ...
E-CIGARETTE DEVICES, USES, AND EXPOSURES 63 Interpuff Puff Duration Interval Flow Rate Puff Count Mean Mean Mean Puff Volume Mean (SD or SE)
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From page 64... ...
64 PUBLIC HEALTH CONSEQUENCES OF E-CIGARETTES TABLE 3-1 Continued Study Nicotine Study Reference Product Content Sample Size Conditions Method Cunningham Vype 4.5% 32 Lab; ad lib modifed SA7 et al., 2016 Reload (1st nicotine (45 over self generation)
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From page 65... ...
E-CIGARETTE DEVICES, USES, AND EXPOSURES 65 Interpuff Puff Duration Interval Flow Rate Puff Count Mean Mean Mean Puff Volume Mean (SD or SE)
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From page 66... ...
measured puffing topography of 13 experienced second-generation e-cigarette users during a 10-puff session in which puffing characteristics such as duration were not standardized. The authors compared the findings with a previously published study on combustible tobacco cigarette smokers (Kleykamp et al., 2008)
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From page 67... ...
reported similar average number of puffs, puff duration, and interpuff interval during a 10-minute ad lib session 5 and 10 days after switching from combustible tobacco cigarettes to e-cigarettes. Based on Table 3-1, in general, puff duration appears to be longer among experienced e-cigarette users (range of means = 1.8 to 5.29 seconds)
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From page 68... ...
Puff volume and puff duration tended to decrease with increasing nicotine concentration, while there was no clear trend with flow rate. In a similar study, Dawkins et al.
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From page 69... ...
demonstrated particle size distribution of aerosols produced by electronic cigarettes in an undiluted state using a spectral transmission procedure after high dilution with an electrical mobility analyzer. They found particle diameters of average mass in the 250- to 450-nm size range with particle number concentrations of 109 particles/cm3.
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From page 70... ...
did follow-up studies using a cascade impactor to determine particle size distribution by collecting eight puffs total (four per e-cigarette) with a 30-second interpuff interval.
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From page 71... ...
, averaged across the different electronic cigarette types and liquids, at 4.4 ± 0.4 × 109 particles/ cm3, compared with the combustible tobacco cigarette at 3.1 ± 0.6 × 109 particles/cm3. Puffing times and nicotine contents were found to influence the particle concentration, whereas no significant differences were recognized in terms of flavors and types of combustible tobacco cigarettes used.
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From page 72... ...
In the gas phase, the particle number concentration (PNC) of e-cigarette aerosols was found to be positively correlated with puff duration, whereas the PNC and size distribution may vary with different flavors and nicotine concentration.
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From page 73... ...
hygroscopic growth rates are higher for e-cigarettes than for combustible tobacco cigarettes; (3) the effect of particle growth on deposition leads to a lower total deposition in the case of combustible tobacco cigarette smoke particles and a higher total deposition in the case of e-cigarette droplets relative to their initial size distributions; and (4)
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From page 74... ...
, on average, will not alter these results; the effects of longer puff duration with e-cigarettes on deposition fractions will be offset in general by their higher puff volume (Evans and Hoffman, 2014; Fuoco et al., 2014; Norton et al., 2014; Winkler-Heil et al., 2014)
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From page 75... ...
With respect to aerosol generation techniques, current machine-based aerosol generation techniques pose several challenges for assessing different product aerosols because many smoking machines and exposure systems were originally designed for use with combustible tobacco cigarettes and do not easily translate to the standard production of e-cigarette aerosols. For example, e-cigarettes require a higher airflow rate and longer puff durations to produce aerosols than combustible tobacco cigarettes require to produce smoke.
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From page 76... ...
. Other important differences between e-cigarette aerosols and combustible tobacco cigarette smoke in such systems include aerosols condensing in transit tubing (possibly restricting aerosol flow and impeding syringe function)
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From page 77... ...
. Increasingly, legislation banning combustible tobacco cigarette smoking in indoor public places has been amended to expand coverage to e-cigarettes (Paradise, 2014)
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From page 78... ...
Characteristics and Chemical Composition of Secondhand E-Cigarette Aerosol For combustible tobacco cigarettes, secondhand smoke is defined as the combination of mainstream (exhaled by the smoker) and sidestream (emitted from the burning cigarette)
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From page 79... ...
. Another chamber study with four volunteers vaping e-cigarettes for 12 puffs with Smooke E-SMART device confirmed that particles increased in real time, although the concentrations were lower compared with secondhand tobacco smoke (Protano et al., 2017)
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From page 80... ...
and total volatile organic compounds (TVOCs) were measured, as well as a 7-hour nicotine concentration (Chen et al., 2017)
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From page 81... ...
The findings from these two studies indicate that e-cigarette aerosol in vaping conventions where many e-cigarette users congregate is a major source of particulate matter, air nicotine, and VOCs, impairing air quality. These exposures can also be a concern for e-cigarette vendors and other venue workers who spend many hours in those places (Chen et al., 2017)
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From page 82... ...
The committee did not identify any studies evaluating health effects or early biomarkers of disease resulting from secondhand exposure to e-cigarette aerosols per se. One study conducted a health impact assessment based on computing disability-adjusted life-years (DALYs)
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From page 83... ...
The figure includes the estimated damage due to second- and thirdhand smoke from combustible tobacco cigarettes as calculated in a previous study from St.Helen et al.
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From page 84... ...
Overall, these exposure studies indicate that e-cigarette vaping contributes to some level of indoor air pollution, which, although lower than what has been observed from secondhand combustible tobacco cigarettes, is above the smoke-free level recommended by the Surgeon General and the WHO FCTC. As with secondhand smoke, children, pregnant women, the elderly, and patients with cardiorespiratory diseases may be at special risk.
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From page 85... ...
2015. Particulate matter from electronic cigarettes and conventional cigarettes: A systematic review and observational study.
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From page 86... ...
2016. Effects of electronic cigarette liquid nicotine concentration on plasma nicotine and puff topography in tobacco cigarette smokers: A preliminary report.
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From page 87... ...
2016. Week long topography study of young adults using electronic cigarettes in their natural environment.
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From page 88... ...
2011. Variability among electronic cigarettes in the pressure drop, airflow rate, and aerosol production.
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