Research article
Main and side stream effects of electronic cigarettes

https://doi.org/10.1016/j.jenvman.2019.01.030Get rights and content

Highlights

  • E-cigarettes are not totally emission free devices.

  • Vaping aerosol is a mixture of VOCs, PMs, metals, nicotine derivatives/impurities.

  • Design, diversity and e-liquid variability are complicating their health assessing.

  • Short- and long-term exposure to humans and the environment is still vague.

Abstract

Over the last decade there has been a significant boost towards the use of electronic cigarettes (e-cigarettes), especially among youth. Different concentrations of propylene glycol (PG) or vegetable glycerin (VG), flavors and nicotine are mixed in plastic cartridges and commercially offered or privately produced by the vapers. During vaping, a mixture of air and vapors is inhaled to the lungs. Since the ingredients of the e-cigarettes are not burned but vaporized (heated), fewer chemicals are emitted. The levels of potentially toxic compounds (e.g. volatile organic compounds (VOCs), particulate matter (PM), metals, radicals, nitrosamines, etc.) emitted from vaping appear to be lower compared to that of tobacco smoking (from combustible cigarettes). Nevertheless, measurable toxic elements and VOCs are still released (e.g. acetaldehyde, formaldehyde, acrolein, benzene, etc.) along with other volatiles associated with e-liquid flavoring and device variability with PG and VG. The wide range of available flavors at various purities along with the heating temperature are important parameters affecting the evolution of VOCs and aerosols. There is lack of standardized short- and long-term epidemiological medical data (chronic exposure) on e-cigarettes effects to users, non-users and the human micro-environment (second- or third-hand exposure). Therefore, the potential health, safety and environmental effects of vaping are reviewed, examined and discussed.

Introduction

Over the last decade, electronic cigarettes (e-cigarettes, also named electronic nicotine delivery systems), that emulate smoking with a smoke-free technique are increasingly prevalent on the market in Western countries. By 2025, the global e-cigarette market is expected to surpass $50 billion. E-cigarettes are a new trend in the modern world and the public's perception differs about their health effects. The tobacco-free nature and the fewer perceived health aspects of vaping are some of the reasons for the significant increasing trend of e-cigarette use, especially among young people. Today, there are more than 10 million e-cigarette users around the world, mainly in the United States, the United Kingdom, France and other European countries (Margham et al., 2016). The legitimacy of e-cigarettes varies, and many countries impose restrictions on or ban the sale and use of e-cigarettes, such as in Australia, Brazil and Canada (Global Tobacco Control,, Trager,). Recently, the US Food and Drug Administration (FDA) announced new regulations that bring e-cigarettes under the same regulations as tobacco (US Food and Drug Administration).

The first inventor of the e-cigarette designed a device through which it was possible to inhale a hot vapor with a smoke flavor. The suggested device was different from Hon Lik's modern e-cigarette (invented and commercialized in China in 2003), but the thought was in the same direction. Under the hypothesis that all the damage and negative consequences arise from burning tobacco, if this was prevented, then the problem would be solved. Thus, paper and tobacco smoke were replaced with warm “aromatic air” (“An Interview with the Inventor of the Electronic Cigarette”, Herbert A Gilbert).

So far, e-cigarettes aggressive marketing resulted in four generations of devices with distinct capabilities. There are several device models (e.g. disposable, rechargeable, pen-style, tank-style) and brands (around 500 (Klager et al., 2017)), but generally their main parts are the power unit (battery), the electric sprayer (producing hot vapor or otherwise “mist”) and the replaceable cartridge containing the e-liquid that is vented and inhaled, when aspirated into the mouthpiece (Etter, 2010). The main constituents of e-liquids are flavors (commercially available 7700 flavors) (Klager et al., 2017) and usually nicotine, which are dissolved in propylene glycol (PG) and/or vegetable glycerol (VG) (Etter, 2010, Schaller et al., 2013, Cheng, 2014). E-cigarettes can potentially emit harmful substances, including nicotine, and its related derivatives and impurities (e.g. nitrosamines, myosmine, cotinine, anatabine, anabasine, and β-nicotyrine), heavy metals (e.g. Cr), Volatile Organic Compounds (VOCs) such as acetaldehyde, acrolein, formaldehyde, polycyclic aromatic compounds (PAHs), and particles (Margham et al., 2016) (“E-Cigarette Use Among Youth and Young Adults: A report of the Surgeon General” 2016)). This was recently revealed in a human analysis study of 5105 participants; urine samples of e-cigarette users showed greater concentrations of nicotine, tobacco-specific nitrosamines, VOCs, and metals compared to non-users, but in lower concentrations compared to cigarette smokers or both users of e-cigarettes and tobacco smokers (Goniewicz et al., 2018).

Boosted by the increasing worldwide prevalence of e-cigarettes and the subsequent growth among youth, there is a societal demand for more knowledge and better understanding of e-cigarettes' effects. Since e-cigarettes are not totally emission free devices but deliver some of the toxicant profile of tobacco smoking to users, a holistic approach on vaping side effects is explored and discussed. The aim of the present study is to raise public awareness and interest towards e-cigarettes wide use and further contribute to more knowledge regarding their safety. So far, limited research has been conducted, conflicting results were published and therefore many unresolved safety and environmental concerns exist. Therefore, in this review, e-cigarette related documentation is presented, issues addressing health and safety threats are highlighted, and special emphasis is given to the neglected environmental aspects.

Section snippets

VOCs sampling and analysis

The aerosol from e-cigarettes consists of specific VOCs associated with the flavors of the e-liquids. The main analytical methods used for exhaled breath VOCs determination are gas chromatography-flame ionization detector (GC/FID) (Margham et al., 2016), gas chromatography-mass spectrometry (GC/MS) (Butler et al., 2015, Peace et al., 2017), thermal desorption (TD-GC/MS) (Schober et al., 2013, Herrington et al., 2015, Marco and Grimalt, 2015), ion mobility spectrometry, IMS (Ulanowska and Ligor,

Medical aspects

In general, there is a lack of long-term epidemiological data on e-cigarette health effects. Nevertheless, their short-term effects remain a popular research task among the medical community. In this content, their impact on the cardiovascular system was recently reviewed by Qasim (Qasim et al., 2017). A step ahead, are the serious concerns raised after the increased risk observed on thrombogenesis as a result of the short term exposure to e-cigarettes (Qasim et al., 2018). The latter is of

Environmental aspects of e-cigarettes

Last but not least, is the addition of new solid wastes (both electronic and plastic waste) to the environment and their unexplored environmental consequences. E-cigarettes producers claim that e-cigarettes are “eco-friendly”, but this is probably a marketing strategy (Chang, 2014). E-cigarettes are increasing and probably require specialized waste management.

Another issue of major concern is the appropriate disposing of “vape” cartridges and lithium ion batteries. Lithium-ion batteries

Conclusions

E-cigarettes are non-combustible tobacco products, where the e-liquid (a mixture of nicotine, various compositions of flavorings, PG and VG, and other ingredients) is heated, to create an aerosol that is inhaled by the user. They have emerged as a hot trend in modern society and present high variability in the composition of flavoring and on device configurations. Their growing popularity is mainly based on the easily inhalable nicotine amounts and the aerosolized e-liquids (e.g. particle

References (87)

  • C. Rawlinson et al.

    Chemical characterisation of aerosols emitted by electronic cigarettes using thermal desorption – gas chromatography – time of flight mass spectrometry

    J. Chromatogr. A

    (2017)
  • T. Saidi et al.

    Exhaled breath analysis using electronic nose and gas chromatography–mass spectrometry for non-invasive diagnosis of chronic kidney disease, diabetes mellitus and healthy subjects

    Sens. Actuators B Chem.

    (2018)
  • Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs.asp?id=243&tid=44 (last accessed...
  • Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs.asp?id=60&tid=17 (last accessed...
  • Application Note 013

    The Bio-VOC – a low-cost, simple device for biological monitoring of VOCs in breath

    Markes Int.

    (2015)
  • 7s Electronic Vapor. Applicable Trade-In/Recyclable 7's Products. 2018. https://www.my7s.com/recycle-program/ (last...
  • N.Z. Abidin et al.

    Electronic cigarettes and indoor air quality: a review of studies using human volunteers

    Rev. Environ. Health

    (2017)
  • T. Alzahrani et al.

    Association between electronic cigarette use and myocardial infarction

    Am. J. Prev. Med.

    (2018)
  • A. Amann et al.

    Methodological issues of sample collection and analysis of exhaled breath

    Maney Publ.

    (2010)
  • An Interview with the Inventor of the Electronic Cigarette, Herbert A Gilbert,...
  • Biomarkers, N., Workflow, B.A., Services, B., n.d. Volatile Organic Compounds as Biomarkers for Disease (Owlstone...
  • K. Breiev et al.

    An online method for the analysis of volatile organic compounds in electronic cigarette aerosol based on proton transfer reaction mass spectrometry

    Rapid Commun. Mass Spectrom.

    (2016)
  • F. Buonocore et al.

    Labelling of Electronic Cigarettes: Regulations and Current Practice

    (2017)
  • I. Burstyn

    Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks

    BMC Public Health

    (2014)
  • B. Buszewski et al.

    Human exhaled air analytics: biomarkers of diseases

    Biomed. Chromatogr.

    (2007)
  • K.E. Butler et al.

    Presumptive Analysis of Electronic Cigarette Aerosol Using Solid-phase Microextraction for Analysis by Gas Chromatography Mass Spectrometry (SPME-GC-MS) and Direct Analysis in Real Time AccuTOF Mass Spectrometry

    (2015)
  • Chang, H., 2014. Research Gaps Related to the Environmental Impacts of Electronic Cigarettes...
  • T. Cheng

    Chemical evaluation of electronic cigarettes

    Tob. Control

    (2014)
  • Z.J. Cheng et al.

    An electronic nose in the discrimination of breath from smokers and non-smokers: a model for toxin exposure

    J. Breath Res.

    (2009)
  • E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General

    (2016)
  • Consumer Advocates for Smoke Free Alternatives Assoc.,...
  • A. De Vincentis et al.

    Breath-print analysis by e-nose for classifying and monitoring chronic liver disease: a proof-of-concept study

    Sci. Rep.

    (2016)
  • A.K. Duell et al.

    Free-base nicotine determination in electronic cigarette liquids by 1H NMR spectroscopy

    Chem. Res. Toxicol.

    (2018)
  • ECYCLE YOUR blu E-CIGARETTES....
  • Electronic cigarette overview”, http://www.casaa.org/electronic-cigarettes/ (last accessed...
  • J.-F. Etter

    Electronic cigarettes: a survey of users

    BMC Public Health

    (2010)
  • European Chemicals Agency (https://echa.europa.eu/information-on-chemicals/annex-vi-to-clp, Table 3-Annex...
  • M. Famele et al.

    The chemical components of electronic cigarette cartridges and refill fluids: review of analytical methods

    Nicotine Tob. Res.

    (2015)
  • K.E. Farsalinos et al.

    Evaluation of electronic cigarette liquids and aerosol for the presence of selected inhalation toxins

    Nicotine Tob. Res.

    (2015)
  • K.E. Farsalinos et al.

    Are metals emitted from electronic cigarettes a reason for health Concern? A risk-assessment analysis of currently available literature

    Int. J. Environ. Res. Public Health

    (2015)
  • F. Di Francesco et al.

    Breath analysis : trends in techniques and clinical applications

    Microchem. J.

    (2005)
  • D. Gallart-Mateu et al.

    Passive exposure to nicotine from e-cigarettes

    Talanta

    (2017)
  • Gearbest. Electronic cigarettes. https://www.gearbest.com. (last accessed...
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