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Main and side stream effects of electronic cigarettes
Journal of Environmental Management 238 (2019) 10–17
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Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman
Research article
Main and side stream effects of electronic cigarettes a
E. Papaefstathiou , M. Stylianou a b
a,b
, A. Agapiou
T
a,∗
Department of Chemistry, University of Cyprus, P.O. Box 20537, Nicosia 1678, Cyprus NIREAS-International Water Research Center, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
A R T I C LE I N FO
A B S T R A C T
Keywords: E-cigarette VOCs Vaping Environmental impact assessment GC-MS
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.
1. 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
Corresponding author. E-mail address: [email protected] (A. Agapiou).
https://doi.org/10.1016/j.jenvman.2019.01.030 Received 6 November 2018; Received in revised form 5 January 2019; Accepted 11 January 2019 0301-4797/ © 2019 Published by Elsevier Ltd.
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(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, tobaccospecific nitrosamines, VOCs, and metals compared to non-users, but in lower concentrations compared to cigarette smokers or both users of ecigarettes 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.
Table 1 VOCs detected in the exhaled air of vapers. VOCs
References
(E)-1-(Methylthio)prop-1-ene 1,2-Propanediol (Propylene Glycol)
Marco and Grimalt (2015) Cheng (2014), Qasim et al. (2017), Hahn et al. (2014) Pellegrino et al. (2012), Schober et al. (2013), Butler et al. (2015) Hahn et al. (2014) Hahn et al. (2014) Pellegrino et al. (2012) Cheng (2014) Pellegrino et al. (2012) Pellegrino et al. (2012) Marco and Grimalt (2015), Schober et al. (2013) Pellegrino et al. (2012) Burstyn (2014) Burstyn (2014) Marco and Grimalt (2015) Pellegrino et al. (2012)
1,3-Butanediol 1,3-Propanediol 1-Hydroxy-2-propanone 1-Methyl phenanthrene 2,3,5,6-Tetramethyl-pyrazine 2,3-Dimethyl pyrazine 2,5-Dimethylfuran 2,5-Dimethyl-pyrazine 2-Butanone 2-Furaldehyde 2-Methylbutanal 3-Hydroxy-2-methyl-4pyranone 3-Methylbutyl-3methylbutanoate 5-Methyl-2-furaldehyde Acetaldehyde
2. Indoor air quality Acetic acid Acetone
2.1. 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, 2008, Gallart-Mateu et al., 2017), selected ion flow tube (SIFT)-MS (Laugesen, 2008), proton transfer reaction (PTR)-MS (Breiev et al., 2016), spectroscopic laser techniques ((Popa et al., 2015, Thrope et al., 2008)) and chemical detectors (Saidi et al., 2018, De Vincentis et al., 2016, Cheng et al., 2009). Tedlar bags are the most common means for the collection of breath samples. However, the emissions of various impurities, such as N,Ndimethylacetamide and phenol (Lourenço and Turner, 2014, Hamblin, 2016, Grabowska-Polanowska et al., 2013), have to be taken into account. Tedlar bags are reusable, but they must thoroughly cleaned with nitrogen streams to avoid contamination problems (Buszewski et al., 2007, Pereira et al., 2015). They are made from chemically inert materials for a wide range of compounds that resist to some extent gas permeability and adsorption of the analyte molecules on its surface. Nalophan bags are also popular due to their low price, inertness and relatively good toughness [4]. Sampling in the bags, is followed by Solid Phase Microextraction (SPME). SPME is an innovative adsorption or extraction solventless technique (“Solid Phase Microextraction (SPME)”). The sample molecules are separated between the matrix, the headspace and the static phase (in the case of a liquid or solid sample) or between the sample and the static phase (in the gaseous samples), as a result of the absorption and/or adsorption process (this depends on the type of coating) (Vas and Vékey, 2004, Brokl et al., 2014). Moreover, thermal desorption tubes and metal canisters are alternative sampling apparatuses for collecting and analyzing breath air sample, since many compounds can be stored in them for months; their main disadvantage is the high cost (Amann et al., 2010). Canisters are stainless steel tanks, undergone electrochemical treatment and the material has been removed from the metallic part to reduce the adsorption of certain compounds and avoid their loss. They are durable, but their use is not suitable for sample collection (due to their cost, storage space, etc.) (Francesco et al., 2005).
Acrolein
Acetoin Allyl alcohol Allyl methyl sulfide Anthracene Benzaldehyde Benzene Benzoic acid Butyl hydroxyl toluene Butyraldehyde Chrysene Decanal Diethylene Glycol Ethanol Ethyl vanillin Ethylbenzene Ethylene Glycol Formaldehyde
Glycerine (Glycerol)
Glyoxal Isooctane Isoprene Limonene isomer m,p-Xylene Menthol Methyl glyoxal Methyl-1,3-cyclopentadiene Methylfuran n-Heptane n-Hexane n-Octane Nonanoic acid n-Pentane o,m,p-Xylene o-Methyl Benzaldehyde
Qasim et al. (2017) Pellegrino et al. (2012) Klager et al. (2017), Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Burstyn (2014), Goniewicz et al. (2014), Goniewicz et al. (2014) Marco and Grimalt (2015), Burstyn (2014) Cheng (2014), Qasim et al. (2017), Marco and Grimalt (2015), Schober et al. (2013), Burstyn (2014) Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Burstyn (2014), Goniewicz et al. (2014) Klager et al. (2017) Margham et al. (2016) Marco and Grimalt (2015) Cheng (2014) Marco and Grimalt (2015), Schober et al. (2013) Marco and Grimalt (2015), Burstyn (2014) Marco and Grimalt (2015) Burstyn (2014) Klager et al. (2017), Margham et al. (2016), Schober et al. (2013) Margham et al. (2016), Schober et al. (2013) Marco and Grimalt (2015) Hahn et al. (2014) Marco and Grimalt (2015) Hahn et al. (2014) Marco and Grimalt (2015) Hahn et al. (2014) Klager et al. (2017), Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Goniewicz et al. (2014) Cheng (2014), Margham et al. (2016), Qasim et al. (2017), Hahn et al. (2014), Pellegrino et al. (2012), Schober et al. (2013), Butler et al. (2015) Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015), Burstyn (2014), Grote and Pawliszyn (1997) Marco and Grimalt (2015), Schober et al. (2013), Burstyn (2014) Cheng (2014), Burstyn (2014), Goniewicz et al. (2014) Hahn et al. (2014), Schober et al. (2013) Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Qasim et al. (2017)
(continued on next page) 11
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The effect of the different e-liquids in combination with various vaporizers, battery power settings and vaping regime was examined and serious concerns were reported on the released VOCs, especially for formaldehyde, diacetyl, acrolein and benzene (Logue et al., 2017).
Table 1 (continued) VOCs
References
o-Toluidine Pent-1-ene Pent-2-ene Phenanthrene Phenol Propan-1-ol Propanal Pyrene Sulfur dioxide Toluene
Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015) Cheng (2014) Marco and Grimalt (2015), Burstyn (2014) Marco and Grimalt (2015) Burstyn (2014) (Cheng, 2014) (Schober et al., 2013) Marco and Grimalt (2015) Cheng (2014), Qasim et al. (2017), Burstyn (2014), Goniewicz et al. (2014), Marco and Grimalt (2015) Pellegrino et al. (2012)
β-Damascon
2.2. Particulate matter (PM) When e-cigarettes are used, liquid particles with a diameter of less than 2.5 μm (PM2,5) are emitted into the indoor air and penetrate deep into the lungs (Pellegrino et al., 2012). These aerosols, which pollute the air, can increase the risk of asthma, heart disease, lung cancer and can interfere with lung function (Pisinger, 2015). Moreover, it has been shown that e-cigarettes could increase the risk of myocardial infarction when humans are exposed on daily basis (Alzahrani et al., 2018). Schober et al. (2013) found that secondary exposure is also possible during vaping sessions, due to airborne PM2,5 concentrations (Schober et al., 2013). However, there are limited studies involving human volunteers vaping in natural settings; thus indoor air quality assessment remains unclear (Abidin et al., 2017). Therefore, second and third-hand exposure of non-users requires further studies.
Another sampling option is through commercial breath samplers, such as Markes International Bio-VOC, which was recently introduced to the market with increasing usage (Kwak et al., 2014). It is simple to use and requires no specialized medical personnel. The main advantage of this sampler is that it collects the last part of the exhaled breath (alveolar air) and thus avoids contamination with VOCs by mouth or bronchial passages; thus provides a useful indication of the corresponding VOC levels in the blood (Application Note 013, The Bio-VOC, 2015). However, because of collection volume limitation, the use of the Bio-VOC sampler is only recommended for the detection of VOCs present at high concentrations, unless repeatable breath sample collections take place (and then transferred to the same adsorbent tube). Finally, another interesting commercial device for breath sampling is ReCIVA (by Owlstone Medical, UK), which is operated using thermal desorption tubes. Large volume of breath (VOCs from the whole body through the circulatory system) is pre-concentrated in sorbent tubes, which makes it possible to detect VOCs at low concentrations (Volatile Organic Compounds as biomarkers for disease - Owlstone Medical). Table 1 presents the identification of some e-cigarettes VOCs according to the literature, whereas Fig. 1 shows an exhaled air SPME-GC/MS chromatogram of a vaper. According to the study of Marco and Grimat, the VOCs produced from the e-cigarettes are much less compared to that of traditional tobacco cigarette smokers (Marco and Grimalt, 2015). This is attributed to the much lower temperatures used in the ecigarette devices compared to traditional smoking, where combustion is taking place instead of heating. The most toxic VOCs identified in the e-cigarette smoke are formaldehyde, acetaldehyde, acrolein, benzene, toluene and aniline (Goniewicz et al., 2014).
2.3. Nicotine and tobacco derivatives E-cigarette manufacturers offer a variety of nicotine strength choices, ranging between zero (0 mg/ml), low (6, 12 mg/ml), medium (18 mg/ml) and high (24 mg/ml). Nicotine solutions (100 mg/ml) are also available and are diluted according to customer demand (Kaisar et al., 2016). The discrepancies between packaging, e-liquid contents and sales of e-cigarettes and refill containers within EU were regulated by the Tobacco Products Directive (TPD, Directive 2014/40/EU), where obligations under the CLP (classification, labeling, packaging) regulation were also ensured. Based on the latter directive, the limit on eliquid nicotine strength is 20 mg/mL, whereas size limits on bottles is 10 mL and 2 mL on tanks. Nicotine is a toxic chemical compound that can be found in nature in tobacco plants. For e-cigarette use, it is still extracted from tobacco and this extraction process leads to some nicotine-derived products that are suspected of being harmful. These impurities, listed in Table 2, are secondary alkaloids. Exposure of youth and pregnant females to nicotine results to negatively health consequences. Some e-liquids are listed as nicotine-free. However, the US FDA found that electronic cigarette cartridges with no nicotine indication, were tested positive for nicotine (Etter, 2010). Thus, in many countries, nicotine levels of e-cigarette are being examined and compared to labels. Melstrom et al. (2017) reported that the use of e-cigarette can lead to secondhand exposure to nicotine (inhalation and dermal contact), because of its accumulation on surfaces and clothing (Melstrom et al., 2017). The use of nuclear magnetic resonance (NMR) spectroscopy revealed the presence two major forms of nicotine in e-cigarettes, protonated and free-base nicotine; the latter is associated with harsh throat sensations when inhaled (Duell et al., 2018). 2.4. Heavy metals In e-cigarettes, the heating coils are usually made of a combination of nickel (Ni) and chromium (Cr) and some other substances. This is the reason that in e-liquids and aerosols many toxic metals were detected (probably leaked from the coils) (Farsalinos et al., 2015b). Ni and Cr were classified by the International Agency for Research on Cancer (IARC) in Group 1 carcinogenic to humans. Nickel has been associated with chronic bronchitis, reduced lung function and lung cancer in exposed people (International Agency for Research on Cancer) (Agency for Toxic Substances & Disease Registry). Chromium has been linked with respiratory tract, irritation of the lining of the nose, rhinorrhea, and breathing problems (asthma, cough, shortness of breath, wheezing) (Agency for Toxic Substances & Disease Registry). In a similar study by
Fig. 1. Indicative Solid Phase Micro Extraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS) chromatogram of exhaled air sample of a vaper (Papaefstathiou et al., 2018). 12
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Table 2 Nicotine and its derivatives. Nicotine L-nicotine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) N′-nitrosonornicotine (NNN) N-nitrosoanabasine (NAB) N′-nitrosoanatabine (NAT) Nicotyrine Cotinine Myosmine
Margham et al. (2016), Qasim et al. (2017), Hahn et al. (2014), Pellegrino et al. (2012), Schober et al. (2013), Marco and Grimalt (2015), Butler et al. (2015) Pellegrino et al. (2012) Cheng (2014), Qasim et al. (2017), Goniewicz et al. (2014), Bansal and Kim (2016) Cheng (2014), Margham et al. (2016), Qasim et al. (2017), Goniewicz et al. (2014), Bansal and Kim (2016) Cheng (2014), Bansal and Kim (2016) Cheng (2014), Bansal and Kim (2016) Marco and Grimalt (2015) Margham et al. (2016) Margham et al. (2016)
(Vardavas et al., 2017). Muthumalage and his co-workers (2018) reported that e-liquid flavors should undergo regulations to reduce the risk of inhalation toxicity, because of user exposure to them. In order to protect public health, their bottles must have a descriptive listing of all ingredients. The eliquids flavors are known to cause inflammatory and oxidative stress responses in lung cells so, e-liquid constituents must be strictly regulated to reduce the risk of lung disease (Muthumalage et al., 2018). E-liquids, according to various studies, can contain small amounts of nitrosamines, formaldehyde (human carcinogen, Carc. 1B European Chemicals Agency (European Chemicals Agency, Annex VI)), acetaldehyde (possibly carcinogenic to humans, Carc. 2 European Chemicals Agency) and acrolein (can cause irritation in the nasal cavity and damage to the lungs). Formaldehyde and acetaldehyde (added as an aromatic compound) were measured in the aerosol of various e-cigarettes and possibly resulted from the heating of propylene glycol (Famele et al., 2015). Tierney et al. (2016) after the analysis of 30 e-liquids, identified aldehydes in several liquids, compounds that could cause respiratory irritation (Tierney et al., 2016). Varlet and his co-workers found formaldehyde and acetaldehyde in all 42 models from 14 brands of e-liquids that they analysed (Varlet et al., 2015). Also, Farsalinos et al. (2015a) examined 159 commercial samples (from 7 countries) and identified diacetyl and acetyl propionyl in 74,2% of them. The majority of the samples entailed the risk of exposure of the users to higher concentration than safety levels (Farsalinos et al., 2015a).
Goniewicz et al. (2014) levels of Ni, Cd and Pb were also detected (Goniewicz et al., 2014). Also, Hess et al. (2017) in addition to nickel and chromium, identified cadmium, lead and manganese in e-cigarettes liquids using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Different variations of these metals were detected from sample to sample, often much higher than the safe limits (Hess et al., 2017). Since it is unknown how much of the metal in the liquid is aerosolized, further research towards this direction is required.
2.5. Flavors In 2014, more than 7700 flavoured e-liquids were sold from 466 brands in the market (Zhu et al., 2014). Since then, the number of ecigarette brands is increasing raising issues on the wide range of commercial flavors, their purity and the heating temperature; the latter, changes according to the e-cigarette device. A wide range of flavoring agents can be added to the nicotine solution including chocolate, caramel, mint, menthol, coffee, cherry, apple, biscuits, watermelon, strawberry, whiskey, cappuccino, hazelnut and many more. An e-liquid (e.g. pineapple flavor) is not just a single compound but a complex mixture of VOCs (as shown in Fig. 2). The apply of a non-targeted TD-GC-time of flight(TOF)-MS method in the e-cigarette aerosols, revealed the presence of various VOCs, polycyclic aromatic hydrocarbons (PAHs) and phthalates in the examined samples (Rawlinson et al., 2017). In another recent study, 90 popular flavor chemicals used in e-cigarettes were quantified in a single analytical run using a robust GC-MS/MS method originated from 25 eliquids samples of 5 different brands (Aszyk et al., 2018). A research on e-liquids conducted on randomly selected samples from the most popular brands (for a variety of flavors and with different nicotine content) in nine European countries revealed that all liquids contain at least one substance that can be considered as dangerous for human health according to the United Nations classification system
2.6. Propylene glycol (PG) and vegetable glycerine (VG) The main component used in e-cigarettes to create vapors (artificial smoke) is PG, although it has not yet been studied for prolonged inhalation and for long-term consumption (Etter, 2010). PG was “generally recognized as safe” for oral ingestion by the FDA. However, completely different values for inhalation may apply, because of the lungs' large exposed surface (Consumer Advocates for Smoke Free Alternatives Assoc.). VG (glycerol) is widely used as a food additive and in the manufacture of drugs. It is used in e-cigarette fluids for the same reason as PG (“Electronic cigarette overview”). E-cigarette fluids vary widely in respect to the PG to VG ratio. This ratio determines the amount of vapor that the user prefers to produce (VG is thicker than PG). High PG ratios produce less vapor and greater sense of inhalation. High VG ratios produce a vapor mass that is denser, bulkier and with less sensation in the throat and mouth [10]. 3. Medical aspects In general, there is a lack of long-term epidemiological data on ecigarette 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
Fig. 2. Solid Phase Micro Extraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS) chromatogram of e-liquid (pineapple). 13
14
O-rings Gloves
Case for e-cigarette Injection syringe Mesh wire, for DIY e-cigarette Flame coil Replacement tank Drip tip
Batteries Li-ion battery (Rechargeable) Battery sleeve, Disposable Battery charger; Portable charging Case (PCC) E-cigarettes Accessories Vapor atomizers E-liquid oil filler bottle E-cigarette Cleaner Set
PG
VG
Nicotine Salt
E-liquid E-juice
Clearomizer
Cartomizer
Vaporizers Atomizer
Stainless Steel, Brass
Stainless steel Nickel, Kanthal Nickel-Chromium
Stainless steel Stainless Steel Needle Tip Small parts
Atomizer tank, Metal mesh, Heating coil, Atomizer base with battery thread Cartomizer, Tank, Polyfill material, Heating coil, Cartomizer, Base with battery thread Drip tip, Clearomizer, Tank, Wick, Clearomizer, Base with battery thread, Heating coil
Stainless steel, zinc alloy, aluminum alloy, etc.
Vapor Mods: (1) mechanical mods and (2) variable voltage mods
Cartridge
Metal
Product
Plastic Resin and PEI material Silicone Plastic
Plastic
Plastic Plastic bottle container
PVC Plastic
PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap
Plastic, polyester filling
Various
Plastic
Package
Package
Package
Package
Paper
Glass
Leather
Cotton
Glass
Electrical circuit
Heavy metals (lead)
Food grade
Electronic components (e.g. batteries, higher resistance atomizers, cartridges and tanks) LED lights (lead)
Miscellaneous
Liquid
VG, PG, water, nicotine, flavour, colourants
PG, VG, nicotine, flavours, colourants and water
Chemicals
The newest and most popular devices. They are usually cylindrical and feature a clear polycarbonate plastic or pyrex glass tank. A clear tank allows to see the level of e-juice inside. E-juice is delivered to the heating coil by ways of a silica wick. Some designs feature top heating coil with longer wicks, others have bottom placed heating coil with short wicks, which allows for easier wick saturation.
Polyfill is wrapped around a heating coil. It soaks e-juice and allows for longer vape time over atomizer. Some designs are housed inside a larger cylindrical tank, to hold even larger capacity of e-juice.
Small capacity. Although there are different designs, the majority have a heating coil on the bottom with metal mesh on top of the coil. Others, utilize silica wick instead of metal mesh
Additional Information
Table 3 Potentially generated waste from e-cigarettes (Vaper Ranks, 2018) (“Gearbest. Electronic cigarettes”) (“Misthub. Tutorial: Atomizer vs. Cartomizer vs. Clearomizer.” 2018).
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specialized waste management. Another issue of major concern is the appropriate disposing of “vape” cartridges and lithium ion batteries. Lithium-ion batteries included in e-cigarettes, contain heavy metals and without proper disposal, could release toxic chemicals to the environment (‘Science for Environment Policy’: European Commission DG Environment News Alert Service, (Lerner et al., 2015). Proper disposal and management of e-cigarettes should be followed in order to avoid future environmental impacts (Lerner et al., 2015) due to the various e-cigarette components (Table 3) such as: lithium batteries, cartridges, vaporizers, plastics, glass vials, wires, metal casings, etc. Nowadays, in the market, there is a variety of e-cigarettes; the most complicated are e-cigarette mods. The latter are classified to mechanical and variable voltage mods. Mechanical mods, have no electronic switches, regulators or chips, relying only on mechanical components and the voltage of the battery used. On the other hand, voltage mods are considered smart e-cigarettes; the user may change the voltage/ wattage output of the device, modify the amount and temperature vapor, while other helpful features are given like LED displays, battery level and number of puffs taken, as well as, software that allows users to upload usage information on their computers or tablets via Bluetooth. All these entail a product with various and different materials that need proper waste management (Vaper Ranks, 2018). The most important parts of e-cigarette that pose a risk to the environment are lithium batteries, cartridges and vaporizers. Lithium batteries that contain heavy metals are collected separately according to Directive 2006/66/ EC on the management of waste batteries. Likewise, waste of electrical and electronic equipment are based on Directive 2012/19/EU which requires from Member States to adopt appropriate measures to minimize their disposal (“Science for Environment Policy. DG, European Commission Alert, Environment News Service”). In Fig. 3, the potential waste load produced by e-cigarettes is shown compared to traditional cigarettes. Improper disposal of e-cigarette cartridges, batteries, and related materials could result in nicotine exposure to children, adults, and animals, to soil and water contamination (Public Health Law Center. Regulating Electronic Cigarettes & Similar Devices, Mitchell Hamline School of Law, 2017). Collected e-cigarettes should not be crashed when collected, in order to reclaim batteries because there is a danger of nicotine residue to enter the environment as a leak. Chang (2014) reported that the amount of e-liquid (PG, VG, nicotine, flavours, colorants, water) left in spent cartridges varied from 19 to 90% (Buonocore et al., 2017). Krause and Townsend (Chang, 2014) investigated the potential of classification of e-cigarette as hazardous waste by measuring metal leaching through the toxicity characteristic leaching procedure (TCLP). Their results revealed that some e-cigarettes showed toxicity characteristics, whereas the majority of them not. They noted though, that manufactures and retailers with unused or expired e-cigarettes and nicotine juice solutions are required to manage these as hazardous wastes upon disposal, due to their large volume. Many e-cigarette manufacturers have started recycling and/or exchange programs for their products (“blu. ECYCLE YOUR blu E-CIGARETTES.”) (“7s Electronic Vapor. Applicable Trade-In/Recyclable 7's Products”, 2018) (“GreenSmoke, E_VAPOR recycling program”, 2018). As such, some companies use rewarding points in order to collect used cartridges. Reward points can then be redeemed for a specific price off the purchase price of a product (“GreenSmoke, E_VAPOR recycling program”, 2018).
Fig. 3. Potential waste load produced by e-cigarettes and traditional cigarettes.
of paramount importance, as in the US cardiovascular disease is the main cause of death and traditional tobacco smoking was highly associated with it. Towards this direction, their effects on the different biological systems (pulmonary, immune, central nervous and others) were also noticed [39]. The vapor condensate of e-cigarette appeared to cause pro-inflammatory effects on human alveolar macrophages (Scott et al., 2018). According to various studies in literature, e-cigarette is still not considered a safe product because (Schaller et al., 2013, Palamidas et al., 2017): (a) PG can cause respiratory irritation and may increase the risk of asthma, (b) Glycerol can cause lipoid pneumonia when inhaled, (c) Nicotine is addictive; therefore rechargeable cartridges with nicotine content are potentially life-threatening, especially for children, (d) Some aerosols contain carcinogenic substances, (e) The possible effects of using of e-cigarettes on health are not yet all known. Other potential public health risks are the possible skin reactions to dermal contact with e-liquids, home-blending risks and dangers due to untested combinations of e-liquids and device or hardware customization. It was also reported that there is no evidence that vapor can damage DNA (which could cause cancer). In contrast, cigarette smoke has been shown to be toxic to cells and also damages DNA (Vaping, 1970's Style: An Interview with One of the Pioneers). On the other hand, vaporized ecigarette fluid was proved cytotoxic, proinflammatory and inhibited phagocytosis in alveolar macrophages (Scott et al., 2018). Other issues of broader public concern are the accidental potential fire hazards and explosions. Finally, another possible risk is the danger of e-cigarettes becoming the gateway to consumption of illegal drugs or to combustible cigarettes. Towards this, commercially available cannabidiol e-liquids were found to contain the synthetic cannabinoid 5FADB and dextromethorphan (Poklis et al., 2019). 4. Environmental aspects of e-cigarettes
5. Conclusions 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
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 15
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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 size), offering to user the sensation of resembling smoking. Although ecigarettes have been the subject of several research studies in the last years, still they remain a very active area of research with many societal aspects. Even inconsistencies with the labeling of e-cigarette refill solutions were reported. Long term epidemiological and toxicological studies reliant on human cells and tissues are still required to fully explore the potential health, safety and environmental effects of e-cigarette usage. The chemical composition of the aerosol may be different from that of e-liquid, as it is heated and under certain conditions based on the device parameters (e.g., the combination of voltage, resistance, wick and air flow), new toxic compounds may be formed. That is why further research is needed to solve the various questions (health, safety and environmental) that exist in relation to the widespread use of ecigarettes.
electronic cigarette liquids by 1H NMR spectroscopy. Chem. Res. Toxicol. 31, 431–434. ECYCLE YOUR blu E-CIGARETTES. https://www.blu.com/en/GB/ecycle-your-blu/ ecycle-your-blu.html?countryselect=true. Electronic cigarette overview”, http://www.casaa.org/electronic-cigarettes/ (last accessed 9/10/2018). Etter, J.-F., 2010. Electronic cigarettes: a survey of users. BMC Public Health 10. European Chemicals Agency (https://echa.europa.eu/information-on-chemicals/annexvi-to-clp, Table 3-Annex VI). Famele, M., Ferranti, C., Abenavoli, C., Palleschi, L., Mancinelli, R., Draisci, R., 2015. The chemical components of electronic cigarette cartridges and refill fluids: review of analytical methods. Nicotine Tob. Res. 17, 271–279. Farsalinos, K.E., Kistler, K.A., Gillman, G., Voudris, V., 2015a. Evaluation of electronic cigarette liquids and aerosol for the presence of selected inhalation toxins. Nicotine Tob. Res. 168–174. Farsalinos, K.E., Voudris, V., Poulas, K., 2015b. 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 5215–5232. Francesco, F. Di, Fuoco, R., Trivella, M.G., Ceccarini, A., 2005. Breath analysis : trends in techniques and clinical applications. Microchem. J. 79, 405–410. Gallart-Mateu, D., Elbal, L., Armenta, S., De La Guardia, M., 2017. Passive exposure to nicotine from e-cigarettes. Talanta 152, 329–334. Gearbest. Electronic cigarettes. https://www.gearbest.com. (last accessed 24/10/18). Global Tobacco Control, http://globaltobaccocontrol.org/e-cigarette/countries (last accessed 5/10/2017). Goniewicz, M.L., Knysak, J., Gawron, M., Kosmider, L., Sobczak, A., Kurek, J., Prokopowicz, A., Jablonska-Czapla, M., Rosik-Dulewska, C., Havel, C., Jacob, P., Benowitz, N., 2014. Levels of selected carcinogens and toxicants in vapor from electronic cigarettes. Tob. Control 23, 133–139. Goniewicz, M.L., Smith, D.M., Edwards, K.C., Blount, B.C., Caldwell, K.L., Feng, J., 2018. Comparison of nicotine and toxicant exposure in users of electronic cigarettes and combustible cigarettes. JAMA Netw. Open 1, 1–16. Grabowska-Polanowska, B., Faber, J., Skowron, M., Miarka, P., Pietrzycka, A., Śliwka, I., Amann, A., 2013. Detection of potential chronic kidney disease markers in breath using gas chromatography with mass-spectral detection coupled with thermal desorption method. J. Chromatogr. A 1301, 179–189. GreenSmoke, 2018. E_VAPOR Recycling Program. https://www.greensmoke.com/ advantages/recycling.html (last accessed 24/10/18). Grote, C., Pawliszyn, J., 1997. Solid-phase microextraction for the analysis of human breath. Anal. Chem. 69, 587–596. Hahn, J., Monakhova, Y.B., Hengen, J., Kohl-Himmelseher, M., Schüssler, J., Hahn, H., Kuballa, T., Lachenmeier, D.W., 2014. Electronic cigarettes: overview of chemical composition and exposure estimation. Tob. Induc. Dis. 12, 23. Hamblin, D.N.D., 2016. Exhaled Breath Analysis of Smokers Using CMV- GC/MS. FIU Electron Theses Diss. Herrington, B.J.S., Myers, C., Rigdon, A., 2015. Analysis of Nicotine and Impurities in Electronic Cigarette Solutions and Vapor. Restek. Hess, C.A., Olmedo, P., Navas-Acien, A., Goessler, W., Cohen, J.E., Rule, A.M., 2017. Ecigarettes as a source of toxic and potentially carcinogenic metals. Environ. Res. 152, 221–225. International Agency for Research on Cancer, https://monographs.iarc.fr/agentsclassified/-by-the-iarc/ (last/ accessed 8/10/18). Kaisar, M.A., Prasad, S., Liles, T., Cucullo, L., 2016. A decade of e-cigarettes: limited research & unresolved safety concerns. Toxicology 365, 67–75. Klager, S., Vallarino, J., MacNaughton, P., Christiani, D.C., Lu, Q., Allen, J.G., 2017. Flavoring chemicals and aldehydes in E-cigarette emissions. Environ. Sci. Technol. 51, 10806–10813. Kwak, J., Fan, M., Harshman, S.W., Garrison, C.E., Dershem, V.L., Phillips, J.B., Grigsby, C.C., Ott, D.K., 2014. Evaluation of Bio-VOC sampler for analysis of volatile organic compounds in exhaled breath. Metabolites 4, 879–888. Laugesen, M., 2008. Second Safety Report on the Ruyan ® e-cigarette. Heal, New Zeal. Lerner, C.A., Sundar, I.K., Watson, R.M., Elder, A., Jones, R., Done, D., Kurtzman, R., Ossip, D.J., Robinson, R., Mcintosh, S., Rahman, I., 2015. Environmental health hazards of e-cigarettes and their components: oxidants and copper in e-cigarette aerosols. Environ. Pollut. 198, 100–107. Logue, J.M., Sleiman, M., Montesinos, V.N., Russell, M.L., Litter, M.I., Benowitz, N.L., Gundel, L.A., Destaillats, H., 2017. Emissions from electronic cigarettes: assessing vapers' intake of toxic compounds, secondhand exposures, and the associated health impacts. Environ. Sci. Technol. 51, 9271–9279. Lourenço, C., Turner, C., 2014. Breath analysis in disease diagnosis: methodological considerations and applications. Metabolites 4, 465–498. Marco, E., Grimalt, J.O., 2015. A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers. J. Chromatogr. A 1410, 51–59. Margham, J., McAdam, K., Forster, M., Liu, C., Wright, C., Mariner, D., Proctor, C., 2016. Chemical composition of aerosol from an E-cigarette: a quantitative comparison with cigarette smoke. Chem. Res. Toxicol. 29, 1662–1678. Melstrom, P., Koszowski, B., Thanner, M.H., Hoh, E., King, B., Bunnell, R., McAfee, T., 2017. Measuring PM2.5, ultrafine particles, nicotine air and wipe samples following the use of electronic cigarettes. Nicotine Tob. Res. 19, 1055–1061. Misthub, 2018. Tutorial: Atomizer vs. Cartomizer vs. Clearomizer. Misthub (last accessed 24/10/18). https://www.misthub.com/blogs/vape-tutorials/76788357-tutorialatomizer-vs-cartomizer-vs-clearomizer. Muthumalage, T., Prinz, M., Ansah, K.O., Gerloff, J., Sundar, I.K., Rahman, I., 2018. Inflammatory and oxidative responses induced by exposure to commonly used ecigarette flavoring chemicals and flavored e-liquids without nicotine. Front. Physiol.
References Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs. asp?id=243&tid=44 (last accessed 8/10/18). Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs. asp?id=60&tid=17 (last accessed 8/10/2018). Application Note 013, 2015. The Bio-VOC – a low-cost, simple device for biological monitoring of VOCs in breath. Markes Int. 44, 1–4. 7s Electronic Vapor. Applicable Trade-In/Recyclable 7's Products. 2018. https://www. my7s.com/recycle-program/ (last accessed 23/10/18). Abidin, N.Z., Abidin, E.Z., Zulkifli, A., Karuppiah, K., Ismail, S.N.S., Nordin, A.S.A., 2017. Electronic cigarettes and indoor air quality: a review of studies using human volunteers. Rev. Environ. Health 235–244. Alzahrani, T., Pena, I., Temesgen, N., Glantz, S.A., 2018. Association between electronic cigarette use and myocardial infarction. Am. J. Prev. Med. 1–7. https://doi.org/10. 1016/j.amepre.2018.05.004. Amann, A., Miekisch, W., PLEIL, J.D., Risby, T., Schubert, J., 2010. Methodological issues of sample collection and analysis of exhaled breath. Maney Publ. 49, 96–114. An Interview with the Inventor of the Electronic Cigarette, Herbert A Gilbert, https:// www.ecigarettedirect.co.uk/ashtray-blog/2013/10/interview-inventor-e-cigaretteherbert-a-gilbert.html (last accessed 15/10/2017). Aszyk, J., Kubica, P., Kacper, M., Namie, J., Wasik, A., Kot-wasik, A., 2018. Evaluation of flavour profiles in e-cigarette refill solutions using gas chromatography – tandem mass spectrometry. J. Chromatogr. A 1547, 86–98. Bansal, V., Kim, K.H., 2016. Review on quantitation methods for hazardous pollutants released by e-cigarette (EC) smoking. TrAC Trends Anal. Chem. 78, 120–133. Biomarkers, N., Workflow, B.A., Services, B., n.d. Volatile Organic Compounds as Biomarkers for Disease (Owlstone Medical). Breiev, K., Burseg, K.M.M., O'Connell, G., Hartungen, E., Biel, S.S., Cahours, X., Colard, S., Märk, T.D., Sulzer, P., 2016. 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. 30, 691–697. Brokl, M., Bishop, L., Wright, C.G., Liu, C., Mcadam, K., 2014. Multivariate Analysis of Mainstream Tobacco Smoke Particulate Phase by Headspace Solid-phase Micro Extraction Coupled with Comprehensive Two-Dimensional Gas Chromatography – Time-Of-Flight Mass Spectrometry 1370. pp. 216–229. Buonocore, F., Gomes, A.C.N.M., Nabhani-gebara, S., Barton, S.J., Calabrese, G., 2017. Labelling of Electronic Cigarettes: Regulations and Current Practice. pp. 46–52. Burstyn, I., 2014. Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks. BMC Public Health 14, 18. Buszewski, B., Kesy, M., Ligor, T., Amann, A., 2007. Human exhaled air analytics: biomarkers of diseases. Biomed. Chromatogr. 553–566. Butler, K.E., Poklis, J., Turner, J.B.M., Poklis, A., Peace, M., 2015. 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. SPME-DART-MS. Chang, H., 2014. Research Gaps Related to the Environmental Impacts of Electronic Cigarettes 54–58. Cheng, T., 2014. Chemical evaluation of electronic cigarettes. Tob. Control 23, ii11–ii17. Cheng, Z.J., Warwick, G., Yates, D.H., Thomas, P.S., 2009. An electronic nose in the discrimination of breath from smokers and non-smokers: a model for toxin exposure. J. Breath Res. 3, 036003. E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General. U.S. Department of Health and Human Services, pp. 1–295. Consumer Advocates for Smoke Free Alternatives Assoc., https://www.atsdr.cdc.gov/ toxprofiles/propylene_glycol_addendum.pdf (last accessed 8/10/2018). De Vincentis, A., Pennazza, G., Santonico, M., Vespasiani-Gentilucci, U., Galati, G., Gallo, P., Vernile, C., Pedone, C., Antonelli Incalzi, R., Picardi, A., 2016. Breath-print analysis by e-nose for classifying and monitoring chronic liver disease: a proof-of-concept study. Sci. Rep. 6, 1–9. Duell, A.K., Pankow, J.F., Peyton, D.H., 2018. Free-base nicotine determination in
16
Journal of Environmental Management 238 (2019) 10–17
E. Papaefstathiou, et al.
Jörres, R.A., Fromme, H., 2013. Use of electronic cigarettes (e-cigarettes) impairs indoor air quality and increases FeNO levels of e-cigarette consumers. Int. J. Hyg. Environ. Health 217, 628–637. “Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by SCU, The University of the West of England, Bristol, http://ec. europa.eu/environment/integration/research/newsalert/pdf/e-cigarette_waste_ poses_potential_en. Science for Environment Policy. DG, European Commission Alert, Environment News Service, Edited By SCU, The University of the West of England, Bristol. Scott, A., Lugg, S.T., Aldridge, K., Lewis, K.E., Bowden, A., Mahida, R.Y., Grudzinska, F.S., Dosanjh, D., Parekh, D., Foronjy, R., Sapey, E., Naidu, B., Thickett, D.R., 2018. Proinflammatory effects of e-cigarette vapour condensate on human alveolar macrophages. Thorax 1–9. Solid Phase Microextraction (SPME) http://www.sigmaaldrich.com/analyticalchromatography/sample-preparation/spme.html, Accessed date: 30 October 2017. Thrope, M.J., Balslev-Clausen, D., Kirchner, M.S., Ye, J., 2008. Cavity-enhanced optical frequency comb spectroscopy: application to human breath analysis. Opt. Express 16, 2387–2397. Tierney, P.A., Karpinski, C.D., Brown, J.E., Luo, W., Pankow, J.F., 2016. Flavour chemicals in electronic cigarette fluids. Tob. Control 25, 10–15. Trager, R., n.d. Going up in vapour, https://www.chemistryworld.com/feature/going-upin-vapour/1010328.article (last accessed 1/10/2017). Ulanowska, A., Ligor, M., 2008. Determination of volatile organic compounds in exhaled breath by ion mobility spectrometry. Chem. Anal. 53, 953–965. US Food and Drug Administration, https://ec.europa.eu/health//sites/health/files/ tobacco/docs/dir_201440_en.pdf (last accessed 11/10/2018). Vaper Ranks, 2018. What Is an E-Cigarette PCC (Portable Charging Case). Vaping 1970's Style: An Interview with One of the Pioneers, https://www. ecigarettedirect.co.uk/ashtray-blog/2014/06/favor-cigarette-interview-dr-normanjacobson.html (last accessed 14/10/2017). Vardavas, C., Tzatzarakis, M., Vardavas, A., Girvalaki, C., Stivaktakis, P., Nikolouzakis, T., Tsatsakis, A., 2017. Evaluation of respiratory irritants among the most popular ecigarette refill liquids across 9 European countries. Eur. Respir. J. 50. Varlet, V., Farsalinos, K., Augsburger, M., Thomas, A., Etter, J.F., 2015. Toxicity assessment of refill liquids for electronic cigarettes. Int. J. Environ. Res. Public Health 12, 4796–4815. Vas, G., Vékey, K., 2004. Solid-phase microextraction: a powerful sample preparation tool prior to mass spectrometric analysis. J. Mass Spectrom. 39, 233–254. Zhu, S., Sun, J.Y., Bonnevie, E., Cummins, S.E., Gamst, A., Yin, L., Lee, M., 2014. Four hundred and sixty brands of e-cigarettes and counting: implications for product regulation. Tob. Control 23 iii3-iii9.
8, 1–13. Palamidas, A., Tsikrika, S., Katsaounou, P.A., Vakali, S., Gennimata, S., Kaltsakas, G., Gratziou, C., Koulouris, N., 2017. Acute effects of short term use of ecigarettes on airways physiology and respiratory symptoms in smokers with and without airway obstructive diseases and in healthy non smokers. Tob. Prev. Cessat. 3, 1–8. Papaefstathiou, E., Stylianou, M., Agapiou, A., 2018. Exploring the side effects of vaping (electronic cigarette). In: Proceedings of the 6th International Conference on Sustainable Solid Waste Management, 13-16 June 2018, Naxos. Peace, M.R., Krakowiak, R.I., Wolf, C.E., Poklis, A., Poklis, J.L., 2017. Identification of MDMB-FUBINACA in commercially available e-liquid formulations sold for use in electronic cigarettes (accepted for publication). Forensic Sci. Int. 271, 92–97. Pellegrino, R.M., Tinghino, B., Mangiaracina, G., Marani, A., Vitali, M., Protano, C., Osborn, J.F., Cattaruzza, M.S., 2012. Electronic cigarettes: an evaluation of exposure to chemicals and fine particulate matter (PM). Ann Ig 24, 279–288. Pereira, J., Porto-Figueira, P., Cavaco, C., Taunk, K., Rapole, S., Dhakne, R., Nagarajaram, H., Câmara, J.S., 2015. Breath analysis as a potential and non-invasive frontier in disease diagnosis: an overview. Metabolites 5, 3–55. Pisinger, C., 2015. A Systematic Review of Health Effects of Electronic Cigarettes. Poklis, J.L., Mulder, H.A., Peace, M.R., 2019. The unexpected identification of the cannabimimetic , 5F-ADB, and dextromethorphan in commercially available cannabidiol e-liquids. Forensic Sci. Int. 294, e25–e27. Popa, C., Banita, S., Patachia, M., Matei, C., Bratu, A.M., Petrus, M., Dumitras, D.C., 2015. Co2 laser-photoacoustic study of exhaled breath produced by electronic vs. Traditional cigarettes. Rom. Rep. Phys. 67, 946–953. Public Health Law Center, 2017. Regulating Electronic Cigarettes & Similar Devices. Mitchell Hamline School of Law, St. Paul, Minnesota. www.publichealthlawcenter. org. Qasim, H., Karim, Z.A., Rivera, J.O., Khasawneh, F.T., Alshbool, F.Z., 2017. Impact of electronic cigarettes on the cardiovascular system. J. Am. Heart Assoc. 6. Qasim, H., Karim, Z.A., Silva-Espinoza, J.C., Khasawneh, F.T., Ellis, C.C., Bauer, S.L., Almeida, I.C., Alshbool, F.Z., 2018. Short-term E-cigarette exposure increases the risk of thrombogenesis and enhances platelet function in mice. Am. Heart Assoc. 13–15. Rawlinson, C., Martin, S., Frosina, J., Wright, C., 2017. Chemical characterisation of aerosols emitted by electronic cigarettes using thermal desorption – gas chromatography – time of flight mass spectrometry. J. Chromatogr. A 1497, 144–154. Saidi, T., Zaim, O., Moufid, M., El Bari, N., Ionescu, R., Bouchikhi, B., 2018. 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. 257, 178–188. Schaller, K., Ruppert, L., Kahnert, S., Bethke, C., Nair, U., Pötschke-Langer, M., 2013. Electronic cigarettes — an overview. Ger. Cancer Res. Cent. 19, 1–52. Schober, W., Szendrei, K., Matzen, W., Osiander-Fuchs, H., Heitmann, D., Schettgen, T.,
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Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman
Research article
Main and side stream effects of electronic cigarettes a
E. Papaefstathiou , M. Stylianou a b
a,b
, A. Agapiou
T
a,∗
Department of Chemistry, University of Cyprus, P.O. Box 20537, Nicosia 1678, Cyprus NIREAS-International Water Research Center, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
A R T I C LE I N FO
A B S T R A C T
Keywords: E-cigarette VOCs Vaping Environmental impact assessment GC-MS
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.
1. 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
Corresponding author. E-mail address: [email protected] (A. Agapiou).
https://doi.org/10.1016/j.jenvman.2019.01.030 Received 6 November 2018; Received in revised form 5 January 2019; Accepted 11 January 2019 0301-4797/ © 2019 Published by Elsevier Ltd.
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(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, tobaccospecific nitrosamines, VOCs, and metals compared to non-users, but in lower concentrations compared to cigarette smokers or both users of ecigarettes 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.
Table 1 VOCs detected in the exhaled air of vapers. VOCs
References
(E)-1-(Methylthio)prop-1-ene 1,2-Propanediol (Propylene Glycol)
Marco and Grimalt (2015) Cheng (2014), Qasim et al. (2017), Hahn et al. (2014) Pellegrino et al. (2012), Schober et al. (2013), Butler et al. (2015) Hahn et al. (2014) Hahn et al. (2014) Pellegrino et al. (2012) Cheng (2014) Pellegrino et al. (2012) Pellegrino et al. (2012) Marco and Grimalt (2015), Schober et al. (2013) Pellegrino et al. (2012) Burstyn (2014) Burstyn (2014) Marco and Grimalt (2015) Pellegrino et al. (2012)
1,3-Butanediol 1,3-Propanediol 1-Hydroxy-2-propanone 1-Methyl phenanthrene 2,3,5,6-Tetramethyl-pyrazine 2,3-Dimethyl pyrazine 2,5-Dimethylfuran 2,5-Dimethyl-pyrazine 2-Butanone 2-Furaldehyde 2-Methylbutanal 3-Hydroxy-2-methyl-4pyranone 3-Methylbutyl-3methylbutanoate 5-Methyl-2-furaldehyde Acetaldehyde
2. Indoor air quality Acetic acid Acetone
2.1. 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, 2008, Gallart-Mateu et al., 2017), selected ion flow tube (SIFT)-MS (Laugesen, 2008), proton transfer reaction (PTR)-MS (Breiev et al., 2016), spectroscopic laser techniques ((Popa et al., 2015, Thrope et al., 2008)) and chemical detectors (Saidi et al., 2018, De Vincentis et al., 2016, Cheng et al., 2009). Tedlar bags are the most common means for the collection of breath samples. However, the emissions of various impurities, such as N,Ndimethylacetamide and phenol (Lourenço and Turner, 2014, Hamblin, 2016, Grabowska-Polanowska et al., 2013), have to be taken into account. Tedlar bags are reusable, but they must thoroughly cleaned with nitrogen streams to avoid contamination problems (Buszewski et al., 2007, Pereira et al., 2015). They are made from chemically inert materials for a wide range of compounds that resist to some extent gas permeability and adsorption of the analyte molecules on its surface. Nalophan bags are also popular due to their low price, inertness and relatively good toughness [4]. Sampling in the bags, is followed by Solid Phase Microextraction (SPME). SPME is an innovative adsorption or extraction solventless technique (“Solid Phase Microextraction (SPME)”). The sample molecules are separated between the matrix, the headspace and the static phase (in the case of a liquid or solid sample) or between the sample and the static phase (in the gaseous samples), as a result of the absorption and/or adsorption process (this depends on the type of coating) (Vas and Vékey, 2004, Brokl et al., 2014). Moreover, thermal desorption tubes and metal canisters are alternative sampling apparatuses for collecting and analyzing breath air sample, since many compounds can be stored in them for months; their main disadvantage is the high cost (Amann et al., 2010). Canisters are stainless steel tanks, undergone electrochemical treatment and the material has been removed from the metallic part to reduce the adsorption of certain compounds and avoid their loss. They are durable, but their use is not suitable for sample collection (due to their cost, storage space, etc.) (Francesco et al., 2005).
Acrolein
Acetoin Allyl alcohol Allyl methyl sulfide Anthracene Benzaldehyde Benzene Benzoic acid Butyl hydroxyl toluene Butyraldehyde Chrysene Decanal Diethylene Glycol Ethanol Ethyl vanillin Ethylbenzene Ethylene Glycol Formaldehyde
Glycerine (Glycerol)
Glyoxal Isooctane Isoprene Limonene isomer m,p-Xylene Menthol Methyl glyoxal Methyl-1,3-cyclopentadiene Methylfuran n-Heptane n-Hexane n-Octane Nonanoic acid n-Pentane o,m,p-Xylene o-Methyl Benzaldehyde
Qasim et al. (2017) Pellegrino et al. (2012) Klager et al. (2017), Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Burstyn (2014), Goniewicz et al. (2014), Goniewicz et al. (2014) Marco and Grimalt (2015), Burstyn (2014) Cheng (2014), Qasim et al. (2017), Marco and Grimalt (2015), Schober et al. (2013), Burstyn (2014) Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Burstyn (2014), Goniewicz et al. (2014) Klager et al. (2017) Margham et al. (2016) Marco and Grimalt (2015) Cheng (2014) Marco and Grimalt (2015), Schober et al. (2013) Marco and Grimalt (2015), Burstyn (2014) Marco and Grimalt (2015) Burstyn (2014) Klager et al. (2017), Margham et al. (2016), Schober et al. (2013) Margham et al. (2016), Schober et al. (2013) Marco and Grimalt (2015) Hahn et al. (2014) Marco and Grimalt (2015) Hahn et al. (2014) Marco and Grimalt (2015) Hahn et al. (2014) Klager et al. (2017), Margham et al. (2016), Qasim et al. (2017), Schober et al. (2013), Goniewicz et al. (2014) Cheng (2014), Margham et al. (2016), Qasim et al. (2017), Hahn et al. (2014), Pellegrino et al. (2012), Schober et al. (2013), Butler et al. (2015) Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015), Burstyn (2014), Grote and Pawliszyn (1997) Marco and Grimalt (2015), Schober et al. (2013), Burstyn (2014) Cheng (2014), Burstyn (2014), Goniewicz et al. (2014) Hahn et al. (2014), Schober et al. (2013) Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Marco and Grimalt (2015) Qasim et al. (2017)
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The effect of the different e-liquids in combination with various vaporizers, battery power settings and vaping regime was examined and serious concerns were reported on the released VOCs, especially for formaldehyde, diacetyl, acrolein and benzene (Logue et al., 2017).
Table 1 (continued) VOCs
References
o-Toluidine Pent-1-ene Pent-2-ene Phenanthrene Phenol Propan-1-ol Propanal Pyrene Sulfur dioxide Toluene
Margham et al. (2016) Marco and Grimalt (2015) Marco and Grimalt (2015) Cheng (2014) Marco and Grimalt (2015), Burstyn (2014) Marco and Grimalt (2015) Burstyn (2014) (Cheng, 2014) (Schober et al., 2013) Marco and Grimalt (2015) Cheng (2014), Qasim et al. (2017), Burstyn (2014), Goniewicz et al. (2014), Marco and Grimalt (2015) Pellegrino et al. (2012)
β-Damascon
2.2. Particulate matter (PM) When e-cigarettes are used, liquid particles with a diameter of less than 2.5 μm (PM2,5) are emitted into the indoor air and penetrate deep into the lungs (Pellegrino et al., 2012). These aerosols, which pollute the air, can increase the risk of asthma, heart disease, lung cancer and can interfere with lung function (Pisinger, 2015). Moreover, it has been shown that e-cigarettes could increase the risk of myocardial infarction when humans are exposed on daily basis (Alzahrani et al., 2018). Schober et al. (2013) found that secondary exposure is also possible during vaping sessions, due to airborne PM2,5 concentrations (Schober et al., 2013). However, there are limited studies involving human volunteers vaping in natural settings; thus indoor air quality assessment remains unclear (Abidin et al., 2017). Therefore, second and third-hand exposure of non-users requires further studies.
Another sampling option is through commercial breath samplers, such as Markes International Bio-VOC, which was recently introduced to the market with increasing usage (Kwak et al., 2014). It is simple to use and requires no specialized medical personnel. The main advantage of this sampler is that it collects the last part of the exhaled breath (alveolar air) and thus avoids contamination with VOCs by mouth or bronchial passages; thus provides a useful indication of the corresponding VOC levels in the blood (Application Note 013, The Bio-VOC, 2015). However, because of collection volume limitation, the use of the Bio-VOC sampler is only recommended for the detection of VOCs present at high concentrations, unless repeatable breath sample collections take place (and then transferred to the same adsorbent tube). Finally, another interesting commercial device for breath sampling is ReCIVA (by Owlstone Medical, UK), which is operated using thermal desorption tubes. Large volume of breath (VOCs from the whole body through the circulatory system) is pre-concentrated in sorbent tubes, which makes it possible to detect VOCs at low concentrations (Volatile Organic Compounds as biomarkers for disease - Owlstone Medical). Table 1 presents the identification of some e-cigarettes VOCs according to the literature, whereas Fig. 1 shows an exhaled air SPME-GC/MS chromatogram of a vaper. According to the study of Marco and Grimat, the VOCs produced from the e-cigarettes are much less compared to that of traditional tobacco cigarette smokers (Marco and Grimalt, 2015). This is attributed to the much lower temperatures used in the ecigarette devices compared to traditional smoking, where combustion is taking place instead of heating. The most toxic VOCs identified in the e-cigarette smoke are formaldehyde, acetaldehyde, acrolein, benzene, toluene and aniline (Goniewicz et al., 2014).
2.3. Nicotine and tobacco derivatives E-cigarette manufacturers offer a variety of nicotine strength choices, ranging between zero (0 mg/ml), low (6, 12 mg/ml), medium (18 mg/ml) and high (24 mg/ml). Nicotine solutions (100 mg/ml) are also available and are diluted according to customer demand (Kaisar et al., 2016). The discrepancies between packaging, e-liquid contents and sales of e-cigarettes and refill containers within EU were regulated by the Tobacco Products Directive (TPD, Directive 2014/40/EU), where obligations under the CLP (classification, labeling, packaging) regulation were also ensured. Based on the latter directive, the limit on eliquid nicotine strength is 20 mg/mL, whereas size limits on bottles is 10 mL and 2 mL on tanks. Nicotine is a toxic chemical compound that can be found in nature in tobacco plants. For e-cigarette use, it is still extracted from tobacco and this extraction process leads to some nicotine-derived products that are suspected of being harmful. These impurities, listed in Table 2, are secondary alkaloids. Exposure of youth and pregnant females to nicotine results to negatively health consequences. Some e-liquids are listed as nicotine-free. However, the US FDA found that electronic cigarette cartridges with no nicotine indication, were tested positive for nicotine (Etter, 2010). Thus, in many countries, nicotine levels of e-cigarette are being examined and compared to labels. Melstrom et al. (2017) reported that the use of e-cigarette can lead to secondhand exposure to nicotine (inhalation and dermal contact), because of its accumulation on surfaces and clothing (Melstrom et al., 2017). The use of nuclear magnetic resonance (NMR) spectroscopy revealed the presence two major forms of nicotine in e-cigarettes, protonated and free-base nicotine; the latter is associated with harsh throat sensations when inhaled (Duell et al., 2018). 2.4. Heavy metals In e-cigarettes, the heating coils are usually made of a combination of nickel (Ni) and chromium (Cr) and some other substances. This is the reason that in e-liquids and aerosols many toxic metals were detected (probably leaked from the coils) (Farsalinos et al., 2015b). Ni and Cr were classified by the International Agency for Research on Cancer (IARC) in Group 1 carcinogenic to humans. Nickel has been associated with chronic bronchitis, reduced lung function and lung cancer in exposed people (International Agency for Research on Cancer) (Agency for Toxic Substances & Disease Registry). Chromium has been linked with respiratory tract, irritation of the lining of the nose, rhinorrhea, and breathing problems (asthma, cough, shortness of breath, wheezing) (Agency for Toxic Substances & Disease Registry). In a similar study by
Fig. 1. Indicative Solid Phase Micro Extraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS) chromatogram of exhaled air sample of a vaper (Papaefstathiou et al., 2018). 12
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Table 2 Nicotine and its derivatives. Nicotine L-nicotine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) N′-nitrosonornicotine (NNN) N-nitrosoanabasine (NAB) N′-nitrosoanatabine (NAT) Nicotyrine Cotinine Myosmine
Margham et al. (2016), Qasim et al. (2017), Hahn et al. (2014), Pellegrino et al. (2012), Schober et al. (2013), Marco and Grimalt (2015), Butler et al. (2015) Pellegrino et al. (2012) Cheng (2014), Qasim et al. (2017), Goniewicz et al. (2014), Bansal and Kim (2016) Cheng (2014), Margham et al. (2016), Qasim et al. (2017), Goniewicz et al. (2014), Bansal and Kim (2016) Cheng (2014), Bansal and Kim (2016) Cheng (2014), Bansal and Kim (2016) Marco and Grimalt (2015) Margham et al. (2016) Margham et al. (2016)
(Vardavas et al., 2017). Muthumalage and his co-workers (2018) reported that e-liquid flavors should undergo regulations to reduce the risk of inhalation toxicity, because of user exposure to them. In order to protect public health, their bottles must have a descriptive listing of all ingredients. The eliquids flavors are known to cause inflammatory and oxidative stress responses in lung cells so, e-liquid constituents must be strictly regulated to reduce the risk of lung disease (Muthumalage et al., 2018). E-liquids, according to various studies, can contain small amounts of nitrosamines, formaldehyde (human carcinogen, Carc. 1B European Chemicals Agency (European Chemicals Agency, Annex VI)), acetaldehyde (possibly carcinogenic to humans, Carc. 2 European Chemicals Agency) and acrolein (can cause irritation in the nasal cavity and damage to the lungs). Formaldehyde and acetaldehyde (added as an aromatic compound) were measured in the aerosol of various e-cigarettes and possibly resulted from the heating of propylene glycol (Famele et al., 2015). Tierney et al. (2016) after the analysis of 30 e-liquids, identified aldehydes in several liquids, compounds that could cause respiratory irritation (Tierney et al., 2016). Varlet and his co-workers found formaldehyde and acetaldehyde in all 42 models from 14 brands of e-liquids that they analysed (Varlet et al., 2015). Also, Farsalinos et al. (2015a) examined 159 commercial samples (from 7 countries) and identified diacetyl and acetyl propionyl in 74,2% of them. The majority of the samples entailed the risk of exposure of the users to higher concentration than safety levels (Farsalinos et al., 2015a).
Goniewicz et al. (2014) levels of Ni, Cd and Pb were also detected (Goniewicz et al., 2014). Also, Hess et al. (2017) in addition to nickel and chromium, identified cadmium, lead and manganese in e-cigarettes liquids using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Different variations of these metals were detected from sample to sample, often much higher than the safe limits (Hess et al., 2017). Since it is unknown how much of the metal in the liquid is aerosolized, further research towards this direction is required.
2.5. Flavors In 2014, more than 7700 flavoured e-liquids were sold from 466 brands in the market (Zhu et al., 2014). Since then, the number of ecigarette brands is increasing raising issues on the wide range of commercial flavors, their purity and the heating temperature; the latter, changes according to the e-cigarette device. A wide range of flavoring agents can be added to the nicotine solution including chocolate, caramel, mint, menthol, coffee, cherry, apple, biscuits, watermelon, strawberry, whiskey, cappuccino, hazelnut and many more. An e-liquid (e.g. pineapple flavor) is not just a single compound but a complex mixture of VOCs (as shown in Fig. 2). The apply of a non-targeted TD-GC-time of flight(TOF)-MS method in the e-cigarette aerosols, revealed the presence of various VOCs, polycyclic aromatic hydrocarbons (PAHs) and phthalates in the examined samples (Rawlinson et al., 2017). In another recent study, 90 popular flavor chemicals used in e-cigarettes were quantified in a single analytical run using a robust GC-MS/MS method originated from 25 eliquids samples of 5 different brands (Aszyk et al., 2018). A research on e-liquids conducted on randomly selected samples from the most popular brands (for a variety of flavors and with different nicotine content) in nine European countries revealed that all liquids contain at least one substance that can be considered as dangerous for human health according to the United Nations classification system
2.6. Propylene glycol (PG) and vegetable glycerine (VG) The main component used in e-cigarettes to create vapors (artificial smoke) is PG, although it has not yet been studied for prolonged inhalation and for long-term consumption (Etter, 2010). PG was “generally recognized as safe” for oral ingestion by the FDA. However, completely different values for inhalation may apply, because of the lungs' large exposed surface (Consumer Advocates for Smoke Free Alternatives Assoc.). VG (glycerol) is widely used as a food additive and in the manufacture of drugs. It is used in e-cigarette fluids for the same reason as PG (“Electronic cigarette overview”). E-cigarette fluids vary widely in respect to the PG to VG ratio. This ratio determines the amount of vapor that the user prefers to produce (VG is thicker than PG). High PG ratios produce less vapor and greater sense of inhalation. High VG ratios produce a vapor mass that is denser, bulkier and with less sensation in the throat and mouth [10]. 3. Medical aspects In general, there is a lack of long-term epidemiological data on ecigarette 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
Fig. 2. Solid Phase Micro Extraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS) chromatogram of e-liquid (pineapple). 13
14
O-rings Gloves
Case for e-cigarette Injection syringe Mesh wire, for DIY e-cigarette Flame coil Replacement tank Drip tip
Batteries Li-ion battery (Rechargeable) Battery sleeve, Disposable Battery charger; Portable charging Case (PCC) E-cigarettes Accessories Vapor atomizers E-liquid oil filler bottle E-cigarette Cleaner Set
PG
VG
Nicotine Salt
E-liquid E-juice
Clearomizer
Cartomizer
Vaporizers Atomizer
Stainless Steel, Brass
Stainless steel Nickel, Kanthal Nickel-Chromium
Stainless steel Stainless Steel Needle Tip Small parts
Atomizer tank, Metal mesh, Heating coil, Atomizer base with battery thread Cartomizer, Tank, Polyfill material, Heating coil, Cartomizer, Base with battery thread Drip tip, Clearomizer, Tank, Wick, Clearomizer, Base with battery thread, Heating coil
Stainless steel, zinc alloy, aluminum alloy, etc.
Vapor Mods: (1) mechanical mods and (2) variable voltage mods
Cartridge
Metal
Product
Plastic Resin and PEI material Silicone Plastic
Plastic
Plastic Plastic bottle container
PVC Plastic
PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap PET plastic bottle and press and twist cap
Plastic, polyester filling
Various
Plastic
Package
Package
Package
Package
Paper
Glass
Leather
Cotton
Glass
Electrical circuit
Heavy metals (lead)
Food grade
Electronic components (e.g. batteries, higher resistance atomizers, cartridges and tanks) LED lights (lead)
Miscellaneous
Liquid
VG, PG, water, nicotine, flavour, colourants
PG, VG, nicotine, flavours, colourants and water
Chemicals
The newest and most popular devices. They are usually cylindrical and feature a clear polycarbonate plastic or pyrex glass tank. A clear tank allows to see the level of e-juice inside. E-juice is delivered to the heating coil by ways of a silica wick. Some designs feature top heating coil with longer wicks, others have bottom placed heating coil with short wicks, which allows for easier wick saturation.
Polyfill is wrapped around a heating coil. It soaks e-juice and allows for longer vape time over atomizer. Some designs are housed inside a larger cylindrical tank, to hold even larger capacity of e-juice.
Small capacity. Although there are different designs, the majority have a heating coil on the bottom with metal mesh on top of the coil. Others, utilize silica wick instead of metal mesh
Additional Information
Table 3 Potentially generated waste from e-cigarettes (Vaper Ranks, 2018) (“Gearbest. Electronic cigarettes”) (“Misthub. Tutorial: Atomizer vs. Cartomizer vs. Clearomizer.” 2018).
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specialized waste management. Another issue of major concern is the appropriate disposing of “vape” cartridges and lithium ion batteries. Lithium-ion batteries included in e-cigarettes, contain heavy metals and without proper disposal, could release toxic chemicals to the environment (‘Science for Environment Policy’: European Commission DG Environment News Alert Service, (Lerner et al., 2015). Proper disposal and management of e-cigarettes should be followed in order to avoid future environmental impacts (Lerner et al., 2015) due to the various e-cigarette components (Table 3) such as: lithium batteries, cartridges, vaporizers, plastics, glass vials, wires, metal casings, etc. Nowadays, in the market, there is a variety of e-cigarettes; the most complicated are e-cigarette mods. The latter are classified to mechanical and variable voltage mods. Mechanical mods, have no electronic switches, regulators or chips, relying only on mechanical components and the voltage of the battery used. On the other hand, voltage mods are considered smart e-cigarettes; the user may change the voltage/ wattage output of the device, modify the amount and temperature vapor, while other helpful features are given like LED displays, battery level and number of puffs taken, as well as, software that allows users to upload usage information on their computers or tablets via Bluetooth. All these entail a product with various and different materials that need proper waste management (Vaper Ranks, 2018). The most important parts of e-cigarette that pose a risk to the environment are lithium batteries, cartridges and vaporizers. Lithium batteries that contain heavy metals are collected separately according to Directive 2006/66/ EC on the management of waste batteries. Likewise, waste of electrical and electronic equipment are based on Directive 2012/19/EU which requires from Member States to adopt appropriate measures to minimize their disposal (“Science for Environment Policy. DG, European Commission Alert, Environment News Service”). In Fig. 3, the potential waste load produced by e-cigarettes is shown compared to traditional cigarettes. Improper disposal of e-cigarette cartridges, batteries, and related materials could result in nicotine exposure to children, adults, and animals, to soil and water contamination (Public Health Law Center. Regulating Electronic Cigarettes & Similar Devices, Mitchell Hamline School of Law, 2017). Collected e-cigarettes should not be crashed when collected, in order to reclaim batteries because there is a danger of nicotine residue to enter the environment as a leak. Chang (2014) reported that the amount of e-liquid (PG, VG, nicotine, flavours, colorants, water) left in spent cartridges varied from 19 to 90% (Buonocore et al., 2017). Krause and Townsend (Chang, 2014) investigated the potential of classification of e-cigarette as hazardous waste by measuring metal leaching through the toxicity characteristic leaching procedure (TCLP). Their results revealed that some e-cigarettes showed toxicity characteristics, whereas the majority of them not. They noted though, that manufactures and retailers with unused or expired e-cigarettes and nicotine juice solutions are required to manage these as hazardous wastes upon disposal, due to their large volume. Many e-cigarette manufacturers have started recycling and/or exchange programs for their products (“blu. ECYCLE YOUR blu E-CIGARETTES.”) (“7s Electronic Vapor. Applicable Trade-In/Recyclable 7's Products”, 2018) (“GreenSmoke, E_VAPOR recycling program”, 2018). As such, some companies use rewarding points in order to collect used cartridges. Reward points can then be redeemed for a specific price off the purchase price of a product (“GreenSmoke, E_VAPOR recycling program”, 2018).
Fig. 3. Potential waste load produced by e-cigarettes and traditional cigarettes.
of paramount importance, as in the US cardiovascular disease is the main cause of death and traditional tobacco smoking was highly associated with it. Towards this direction, their effects on the different biological systems (pulmonary, immune, central nervous and others) were also noticed [39]. The vapor condensate of e-cigarette appeared to cause pro-inflammatory effects on human alveolar macrophages (Scott et al., 2018). According to various studies in literature, e-cigarette is still not considered a safe product because (Schaller et al., 2013, Palamidas et al., 2017): (a) PG can cause respiratory irritation and may increase the risk of asthma, (b) Glycerol can cause lipoid pneumonia when inhaled, (c) Nicotine is addictive; therefore rechargeable cartridges with nicotine content are potentially life-threatening, especially for children, (d) Some aerosols contain carcinogenic substances, (e) The possible effects of using of e-cigarettes on health are not yet all known. Other potential public health risks are the possible skin reactions to dermal contact with e-liquids, home-blending risks and dangers due to untested combinations of e-liquids and device or hardware customization. It was also reported that there is no evidence that vapor can damage DNA (which could cause cancer). In contrast, cigarette smoke has been shown to be toxic to cells and also damages DNA (Vaping, 1970's Style: An Interview with One of the Pioneers). On the other hand, vaporized ecigarette fluid was proved cytotoxic, proinflammatory and inhibited phagocytosis in alveolar macrophages (Scott et al., 2018). Other issues of broader public concern are the accidental potential fire hazards and explosions. Finally, another possible risk is the danger of e-cigarettes becoming the gateway to consumption of illegal drugs or to combustible cigarettes. Towards this, commercially available cannabidiol e-liquids were found to contain the synthetic cannabinoid 5FADB and dextromethorphan (Poklis et al., 2019). 4. Environmental aspects of e-cigarettes
5. Conclusions 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
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 15
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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 size), offering to user the sensation of resembling smoking. Although ecigarettes have been the subject of several research studies in the last years, still they remain a very active area of research with many societal aspects. Even inconsistencies with the labeling of e-cigarette refill solutions were reported. Long term epidemiological and toxicological studies reliant on human cells and tissues are still required to fully explore the potential health, safety and environmental effects of e-cigarette usage. The chemical composition of the aerosol may be different from that of e-liquid, as it is heated and under certain conditions based on the device parameters (e.g., the combination of voltage, resistance, wick and air flow), new toxic compounds may be formed. That is why further research is needed to solve the various questions (health, safety and environmental) that exist in relation to the widespread use of ecigarettes.
electronic cigarette liquids by 1H NMR spectroscopy. Chem. Res. Toxicol. 31, 431–434. ECYCLE YOUR blu E-CIGARETTES. https://www.blu.com/en/GB/ecycle-your-blu/ ecycle-your-blu.html?countryselect=true. Electronic cigarette overview”, http://www.casaa.org/electronic-cigarettes/ (last accessed 9/10/2018). Etter, J.-F., 2010. Electronic cigarettes: a survey of users. BMC Public Health 10. European Chemicals Agency (https://echa.europa.eu/information-on-chemicals/annexvi-to-clp, Table 3-Annex VI). Famele, M., Ferranti, C., Abenavoli, C., Palleschi, L., Mancinelli, R., Draisci, R., 2015. The chemical components of electronic cigarette cartridges and refill fluids: review of analytical methods. Nicotine Tob. Res. 17, 271–279. Farsalinos, K.E., Kistler, K.A., Gillman, G., Voudris, V., 2015a. Evaluation of electronic cigarette liquids and aerosol for the presence of selected inhalation toxins. Nicotine Tob. Res. 168–174. Farsalinos, K.E., Voudris, V., Poulas, K., 2015b. 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 5215–5232. Francesco, F. Di, Fuoco, R., Trivella, M.G., Ceccarini, A., 2005. Breath analysis : trends in techniques and clinical applications. Microchem. J. 79, 405–410. Gallart-Mateu, D., Elbal, L., Armenta, S., De La Guardia, M., 2017. Passive exposure to nicotine from e-cigarettes. Talanta 152, 329–334. Gearbest. Electronic cigarettes. https://www.gearbest.com. (last accessed 24/10/18). Global Tobacco Control, http://globaltobaccocontrol.org/e-cigarette/countries (last accessed 5/10/2017). Goniewicz, M.L., Knysak, J., Gawron, M., Kosmider, L., Sobczak, A., Kurek, J., Prokopowicz, A., Jablonska-Czapla, M., Rosik-Dulewska, C., Havel, C., Jacob, P., Benowitz, N., 2014. Levels of selected carcinogens and toxicants in vapor from electronic cigarettes. Tob. Control 23, 133–139. Goniewicz, M.L., Smith, D.M., Edwards, K.C., Blount, B.C., Caldwell, K.L., Feng, J., 2018. Comparison of nicotine and toxicant exposure in users of electronic cigarettes and combustible cigarettes. JAMA Netw. Open 1, 1–16. Grabowska-Polanowska, B., Faber, J., Skowron, M., Miarka, P., Pietrzycka, A., Śliwka, I., Amann, A., 2013. Detection of potential chronic kidney disease markers in breath using gas chromatography with mass-spectral detection coupled with thermal desorption method. J. Chromatogr. A 1301, 179–189. GreenSmoke, 2018. E_VAPOR Recycling Program. https://www.greensmoke.com/ advantages/recycling.html (last accessed 24/10/18). Grote, C., Pawliszyn, J., 1997. Solid-phase microextraction for the analysis of human breath. Anal. Chem. 69, 587–596. Hahn, J., Monakhova, Y.B., Hengen, J., Kohl-Himmelseher, M., Schüssler, J., Hahn, H., Kuballa, T., Lachenmeier, D.W., 2014. Electronic cigarettes: overview of chemical composition and exposure estimation. Tob. Induc. Dis. 12, 23. Hamblin, D.N.D., 2016. Exhaled Breath Analysis of Smokers Using CMV- GC/MS. FIU Electron Theses Diss. Herrington, B.J.S., Myers, C., Rigdon, A., 2015. Analysis of Nicotine and Impurities in Electronic Cigarette Solutions and Vapor. Restek. Hess, C.A., Olmedo, P., Navas-Acien, A., Goessler, W., Cohen, J.E., Rule, A.M., 2017. Ecigarettes as a source of toxic and potentially carcinogenic metals. Environ. Res. 152, 221–225. International Agency for Research on Cancer, https://monographs.iarc.fr/agentsclassified/-by-the-iarc/ (last/ accessed 8/10/18). Kaisar, M.A., Prasad, S., Liles, T., Cucullo, L., 2016. A decade of e-cigarettes: limited research & unresolved safety concerns. Toxicology 365, 67–75. Klager, S., Vallarino, J., MacNaughton, P., Christiani, D.C., Lu, Q., Allen, J.G., 2017. Flavoring chemicals and aldehydes in E-cigarette emissions. Environ. Sci. Technol. 51, 10806–10813. Kwak, J., Fan, M., Harshman, S.W., Garrison, C.E., Dershem, V.L., Phillips, J.B., Grigsby, C.C., Ott, D.K., 2014. Evaluation of Bio-VOC sampler for analysis of volatile organic compounds in exhaled breath. Metabolites 4, 879–888. Laugesen, M., 2008. Second Safety Report on the Ruyan ® e-cigarette. Heal, New Zeal. Lerner, C.A., Sundar, I.K., Watson, R.M., Elder, A., Jones, R., Done, D., Kurtzman, R., Ossip, D.J., Robinson, R., Mcintosh, S., Rahman, I., 2015. Environmental health hazards of e-cigarettes and their components: oxidants and copper in e-cigarette aerosols. Environ. Pollut. 198, 100–107. Logue, J.M., Sleiman, M., Montesinos, V.N., Russell, M.L., Litter, M.I., Benowitz, N.L., Gundel, L.A., Destaillats, H., 2017. Emissions from electronic cigarettes: assessing vapers' intake of toxic compounds, secondhand exposures, and the associated health impacts. Environ. Sci. Technol. 51, 9271–9279. Lourenço, C., Turner, C., 2014. Breath analysis in disease diagnosis: methodological considerations and applications. Metabolites 4, 465–498. Marco, E., Grimalt, J.O., 2015. A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers. J. Chromatogr. A 1410, 51–59. Margham, J., McAdam, K., Forster, M., Liu, C., Wright, C., Mariner, D., Proctor, C., 2016. Chemical composition of aerosol from an E-cigarette: a quantitative comparison with cigarette smoke. Chem. Res. Toxicol. 29, 1662–1678. Melstrom, P., Koszowski, B., Thanner, M.H., Hoh, E., King, B., Bunnell, R., McAfee, T., 2017. Measuring PM2.5, ultrafine particles, nicotine air and wipe samples following the use of electronic cigarettes. Nicotine Tob. Res. 19, 1055–1061. Misthub, 2018. Tutorial: Atomizer vs. Cartomizer vs. Clearomizer. Misthub (last accessed 24/10/18). https://www.misthub.com/blogs/vape-tutorials/76788357-tutorialatomizer-vs-cartomizer-vs-clearomizer. Muthumalage, T., Prinz, M., Ansah, K.O., Gerloff, J., Sundar, I.K., Rahman, I., 2018. Inflammatory and oxidative responses induced by exposure to commonly used ecigarette flavoring chemicals and flavored e-liquids without nicotine. Front. Physiol.
References Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs. asp?id=243&tid=44 (last accessed 8/10/18). Agency for Toxic Substances & Disease Registry, https://www.atsdr.cdc.gov/phs/phs. asp?id=60&tid=17 (last accessed 8/10/2018). Application Note 013, 2015. The Bio-VOC – a low-cost, simple device for biological monitoring of VOCs in breath. Markes Int. 44, 1–4. 7s Electronic Vapor. Applicable Trade-In/Recyclable 7's Products. 2018. https://www. my7s.com/recycle-program/ (last accessed 23/10/18). Abidin, N.Z., Abidin, E.Z., Zulkifli, A., Karuppiah, K., Ismail, S.N.S., Nordin, A.S.A., 2017. Electronic cigarettes and indoor air quality: a review of studies using human volunteers. Rev. Environ. Health 235–244. Alzahrani, T., Pena, I., Temesgen, N., Glantz, S.A., 2018. Association between electronic cigarette use and myocardial infarction. Am. J. Prev. Med. 1–7. https://doi.org/10. 1016/j.amepre.2018.05.004. Amann, A., Miekisch, W., PLEIL, J.D., Risby, T., Schubert, J., 2010. Methodological issues of sample collection and analysis of exhaled breath. Maney Publ. 49, 96–114. An Interview with the Inventor of the Electronic Cigarette, Herbert A Gilbert, https:// www.ecigarettedirect.co.uk/ashtray-blog/2013/10/interview-inventor-e-cigaretteherbert-a-gilbert.html (last accessed 15/10/2017). Aszyk, J., Kubica, P., Kacper, M., Namie, J., Wasik, A., Kot-wasik, A., 2018. Evaluation of flavour profiles in e-cigarette refill solutions using gas chromatography – tandem mass spectrometry. J. Chromatogr. A 1547, 86–98. Bansal, V., Kim, K.H., 2016. Review on quantitation methods for hazardous pollutants released by e-cigarette (EC) smoking. TrAC Trends Anal. Chem. 78, 120–133. Biomarkers, N., Workflow, B.A., Services, B., n.d. Volatile Organic Compounds as Biomarkers for Disease (Owlstone Medical). Breiev, K., Burseg, K.M.M., O'Connell, G., Hartungen, E., Biel, S.S., Cahours, X., Colard, S., Märk, T.D., Sulzer, P., 2016. 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. 30, 691–697. Brokl, M., Bishop, L., Wright, C.G., Liu, C., Mcadam, K., 2014. Multivariate Analysis of Mainstream Tobacco Smoke Particulate Phase by Headspace Solid-phase Micro Extraction Coupled with Comprehensive Two-Dimensional Gas Chromatography – Time-Of-Flight Mass Spectrometry 1370. pp. 216–229. Buonocore, F., Gomes, A.C.N.M., Nabhani-gebara, S., Barton, S.J., Calabrese, G., 2017. Labelling of Electronic Cigarettes: Regulations and Current Practice. pp. 46–52. Burstyn, I., 2014. Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks. BMC Public Health 14, 18. Buszewski, B., Kesy, M., Ligor, T., Amann, A., 2007. Human exhaled air analytics: biomarkers of diseases. Biomed. Chromatogr. 553–566. Butler, K.E., Poklis, J., Turner, J.B.M., Poklis, A., Peace, M., 2015. 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. SPME-DART-MS. Chang, H., 2014. Research Gaps Related to the Environmental Impacts of Electronic Cigarettes 54–58. Cheng, T., 2014. Chemical evaluation of electronic cigarettes. Tob. Control 23, ii11–ii17. Cheng, Z.J., Warwick, G., Yates, D.H., Thomas, P.S., 2009. An electronic nose in the discrimination of breath from smokers and non-smokers: a model for toxin exposure. J. Breath Res. 3, 036003. E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General. U.S. Department of Health and Human Services, pp. 1–295. Consumer Advocates for Smoke Free Alternatives Assoc., https://www.atsdr.cdc.gov/ toxprofiles/propylene_glycol_addendum.pdf (last accessed 8/10/2018). De Vincentis, A., Pennazza, G., Santonico, M., Vespasiani-Gentilucci, U., Galati, G., Gallo, P., Vernile, C., Pedone, C., Antonelli Incalzi, R., Picardi, A., 2016. Breath-print analysis by e-nose for classifying and monitoring chronic liver disease: a proof-of-concept study. Sci. Rep. 6, 1–9. Duell, A.K., Pankow, J.F., Peyton, D.H., 2018. Free-base nicotine determination in
16
Journal of Environmental Management 238 (2019) 10–17
E. Papaefstathiou, et al.
Jörres, R.A., Fromme, H., 2013. Use of electronic cigarettes (e-cigarettes) impairs indoor air quality and increases FeNO levels of e-cigarette consumers. Int. J. Hyg. Environ. Health 217, 628–637. “Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by SCU, The University of the West of England, Bristol, http://ec. europa.eu/environment/integration/research/newsalert/pdf/e-cigarette_waste_ poses_potential_en. Science for Environment Policy. DG, European Commission Alert, Environment News Service, Edited By SCU, The University of the West of England, Bristol. Scott, A., Lugg, S.T., Aldridge, K., Lewis, K.E., Bowden, A., Mahida, R.Y., Grudzinska, F.S., Dosanjh, D., Parekh, D., Foronjy, R., Sapey, E., Naidu, B., Thickett, D.R., 2018. Proinflammatory effects of e-cigarette vapour condensate on human alveolar macrophages. Thorax 1–9. Solid Phase Microextraction (SPME) http://www.sigmaaldrich.com/analyticalchromatography/sample-preparation/spme.html, Accessed date: 30 October 2017. Thrope, M.J., Balslev-Clausen, D., Kirchner, M.S., Ye, J., 2008. Cavity-enhanced optical frequency comb spectroscopy: application to human breath analysis. Opt. Express 16, 2387–2397. Tierney, P.A., Karpinski, C.D., Brown, J.E., Luo, W., Pankow, J.F., 2016. Flavour chemicals in electronic cigarette fluids. Tob. Control 25, 10–15. Trager, R., n.d. Going up in vapour, https://www.chemistryworld.com/feature/going-upin-vapour/1010328.article (last accessed 1/10/2017). Ulanowska, A., Ligor, M., 2008. Determination of volatile organic compounds in exhaled breath by ion mobility spectrometry. Chem. Anal. 53, 953–965. US Food and Drug Administration, https://ec.europa.eu/health//sites/health/files/ tobacco/docs/dir_201440_en.pdf (last accessed 11/10/2018). Vaper Ranks, 2018. What Is an E-Cigarette PCC (Portable Charging Case). Vaping 1970's Style: An Interview with One of the Pioneers, https://www. ecigarettedirect.co.uk/ashtray-blog/2014/06/favor-cigarette-interview-dr-normanjacobson.html (last accessed 14/10/2017). Vardavas, C., Tzatzarakis, M., Vardavas, A., Girvalaki, C., Stivaktakis, P., Nikolouzakis, T., Tsatsakis, A., 2017. Evaluation of respiratory irritants among the most popular ecigarette refill liquids across 9 European countries. Eur. Respir. J. 50. Varlet, V., Farsalinos, K., Augsburger, M., Thomas, A., Etter, J.F., 2015. Toxicity assessment of refill liquids for electronic cigarettes. Int. J. Environ. Res. Public Health 12, 4796–4815. Vas, G., Vékey, K., 2004. Solid-phase microextraction: a powerful sample preparation tool prior to mass spectrometric analysis. J. Mass Spectrom. 39, 233–254. Zhu, S., Sun, J.Y., Bonnevie, E., Cummins, S.E., Gamst, A., Yin, L., Lee, M., 2014. Four hundred and sixty brands of e-cigarettes and counting: implications for product regulation. Tob. Control 23 iii3-iii9.
8, 1–13. Palamidas, A., Tsikrika, S., Katsaounou, P.A., Vakali, S., Gennimata, S., Kaltsakas, G., Gratziou, C., Koulouris, N., 2017. Acute effects of short term use of ecigarettes on airways physiology and respiratory symptoms in smokers with and without airway obstructive diseases and in healthy non smokers. Tob. Prev. Cessat. 3, 1–8. Papaefstathiou, E., Stylianou, M., Agapiou, A., 2018. Exploring the side effects of vaping (electronic cigarette). In: Proceedings of the 6th International Conference on Sustainable Solid Waste Management, 13-16 June 2018, Naxos. Peace, M.R., Krakowiak, R.I., Wolf, C.E., Poklis, A., Poklis, J.L., 2017. Identification of MDMB-FUBINACA in commercially available e-liquid formulations sold for use in electronic cigarettes (accepted for publication). Forensic Sci. Int. 271, 92–97. Pellegrino, R.M., Tinghino, B., Mangiaracina, G., Marani, A., Vitali, M., Protano, C., Osborn, J.F., Cattaruzza, M.S., 2012. Electronic cigarettes: an evaluation of exposure to chemicals and fine particulate matter (PM). Ann Ig 24, 279–288. Pereira, J., Porto-Figueira, P., Cavaco, C., Taunk, K., Rapole, S., Dhakne, R., Nagarajaram, H., Câmara, J.S., 2015. Breath analysis as a potential and non-invasive frontier in disease diagnosis: an overview. Metabolites 5, 3–55. Pisinger, C., 2015. A Systematic Review of Health Effects of Electronic Cigarettes. Poklis, J.L., Mulder, H.A., Peace, M.R., 2019. The unexpected identification of the cannabimimetic , 5F-ADB, and dextromethorphan in commercially available cannabidiol e-liquids. Forensic Sci. Int. 294, e25–e27. Popa, C., Banita, S., Patachia, M., Matei, C., Bratu, A.M., Petrus, M., Dumitras, D.C., 2015. Co2 laser-photoacoustic study of exhaled breath produced by electronic vs. Traditional cigarettes. Rom. Rep. Phys. 67, 946–953. Public Health Law Center, 2017. Regulating Electronic Cigarettes & Similar Devices. Mitchell Hamline School of Law, St. Paul, Minnesota. www.publichealthlawcenter. org. Qasim, H., Karim, Z.A., Rivera, J.O., Khasawneh, F.T., Alshbool, F.Z., 2017. Impact of electronic cigarettes on the cardiovascular system. J. Am. Heart Assoc. 6. Qasim, H., Karim, Z.A., Silva-Espinoza, J.C., Khasawneh, F.T., Ellis, C.C., Bauer, S.L., Almeida, I.C., Alshbool, F.Z., 2018. Short-term E-cigarette exposure increases the risk of thrombogenesis and enhances platelet function in mice. Am. Heart Assoc. 13–15. Rawlinson, C., Martin, S., Frosina, J., Wright, C., 2017. Chemical characterisation of aerosols emitted by electronic cigarettes using thermal desorption – gas chromatography – time of flight mass spectrometry. J. Chromatogr. A 1497, 144–154. Saidi, T., Zaim, O., Moufid, M., El Bari, N., Ionescu, R., Bouchikhi, B., 2018. 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. 257, 178–188. Schaller, K., Ruppert, L., Kahnert, S., Bethke, C., Nair, U., Pötschke-Langer, M., 2013. Electronic cigarettes — an overview. Ger. Cancer Res. Cent. 19, 1–52. Schober, W., Szendrei, K., Matzen, W., Osiander-Fuchs, H., Heitmann, D., Schettgen, T.,
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