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SIGNIFICANCE: IQOS is a heated tobacco product that has been widely advertised by Philip Morris International (PMI) as a reduced-exposure product compared with cigarettes. Reduced exposure results from reduced emission of toxicants which could be influenced by product constituents and user behaviour. This study aims to assess the influence of user behaviour, including device cleaning and puffing parameters, on toxicant emissions from IQOS. METHODS: IQOS aerosols were generated by a smoking machine using the combination of two cleaning protocols (after 1 stick vs 20 sticks) and five puffing regimes (including standard cigarette puffing regimes and IQOS-tailored regimes). The generated aerosols were analysed by targeted methods for phenol and carbonyl quantification, and by chemical screening for the identification of unknown compounds. RESULTS: Puffing parameters significantly affected phenol and carbonyl emissions while device cleaning had no effect. Harsher puffing conditions like more, longer, and larger puffs yielded higher levels for most toxicant emissions. Comparing the obtained data with data reported by PMI on 50 cigarette brands smoked under different puffing regimes showed various trends for phenol and carbonyl emissions, with IQOS emissions sometimes higher than cigarettes. Also, the chemical screening resulted in the tentative identification of ~100 compounds in the IQOS aerosols (most of limited toxicity data). CONCLUSION: This study showed that puffing parameters, but not device cleaning, have significant effects on carbonyl, phenol and other emissions. Data analysis highlighted the importance of comparing IQOS emissions with an array of commercial cigarettes tested under different puffing regimes before accepting reduced exposure claims.
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INTRODUCTION: Tobacco smoking is a major cause of disease and premature death worldwide. While nicotine is recognised as the main addictive component in tobacco smoke, the total nicotine amount emitted (nicotine yield) and the rate of nicotine emission per second ('nicotine flux') contribute to the abuse liability of a given product. These variables can be regulated for public health ends and conveniently so for electronic cigarettes or electronic nicotine delivery systems (ENDS). METHODS: In this study we computed nicotine flux from previously reported values of yield and puff topography for a wide range of tobacco products. RESULTS: We found that nicotine flux varied widely across tobacco products, from less than 0.1 µg/s to more than 100 µg/s, and that since 2015 the upper limit of the ENDS nicotine flux range has risen significantly and is now approaching that of combustible cigarettes. We also found that products that differ in nicotine flux may exhibit similar nicotine yields due to differences in user puffing behavior. Nicotine flux is a tool that can be used to regulate nicotine emissions of tobacco products, including ENDS.
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Waterpipe tobacco smoking is a global epidemic. A persistent perception among users is that the water bubbler filters the smoke, reducing its risk profile. The objectives of this study were to quantify the purported filtering effect by comparing toxicant yield when a waterpipe was machine smoked with and without the smoke passing through the water bubbler. We found that the water bubbler did not reduce CO, NO, polycyclic aromatic hydrocarbons (PAHs), or dry particulate matter (DPM) yields but did reduce nicotine and carbonyl compounds (CCs) yields by approximately 50%. These mixed results were consistent with theoretical simulations of the mass transport processes involved.
Assuntos
Monóxido de Carbono/análise , Óxido Nítrico/análise , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluição por Fumaça de Tabaco/análise , Tabaco para Cachimbos de Água/análise , HumanosRESUMO
Electronic cigarettes (ECIGs) are a class of tobacco products that emit a nicotine-containing aerosol by heating and vaporizing a liquid. Apart from initiating nicotine addiction in nonsmokers, a persistent concern about these products is that their emissions often include high levels of carbonyl species, toxicants thought to cause most noncancer pulmonary diseases in smokers. This study examined whether the phenomenon of film boiling can account for observations of high carbonyl emissions under certain operating conditions and, if so, whether film boiling theory can be invoked to predict conditions where high carbonyl emissions are likely. We measured the critical heat flux for several common heating materials and liquids and carbonyl emissions for several ECIG types while varying the power. We found that emissions rise drastically whenever the power exceeds the value corresponding to the critical heat flux. While limiting the heat flux to below this threshold can greatly reduce carbonyl exposure, ECIG manufacturer operating instructions often exceed it. Product regulations that limit heat flux may reduce the public health burden of electronic cigarette use.
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Waterpipe tobacco smoking (WTS) has been characterized as a global epidemic. Waterpipe smoke has been shown to contain and deliver significant doses of many of the toxicants known to cause cancer, respiratory, and cardiovascular diseases in cigarette smokers. It has also been shown that the charcoal used to heat the tobacco contributes most of the polycyclic aromatic hydrocarbons (PAHs) and carbon monoxide (CO) found in the smoke, two major causative agents in smoking-related lung cancer and heart disease, respectively. Possibly as a result of growing awareness of charcoal as a toxicant source, electrical heating elements (EHEs) are being marketed for waterpipe use as reduced harm charcoal substitutes. We measured thermal performance characteristics (tobacco burned, total aerosolized particulate matter) and toxicant emissions in WTS generated using three commercially available waterpipe EHEs and charcoal to examine the hypothesis that EHEs can function similarly to charcoal while presenting a reduced toxicant profile. Toxicants quantified included total particulate matter, nicotine, PAHs, CO, and volatile aldehydes delivered at the mouthpiece when the waterpipe was machine smoked using a standard protocol. We found that while EHEs involved an 80% reduction in total PAH and a 90% reduction in CO emissions, they also resulted in a several-fold increase in the potent respiratory toxicant acrolein. These mixed findings underscore the complexity of toxicant reduction by product manipulation and suggest that marketing EHEs as reduced harm products may be misleading.