When do science recommendations stop being effective? The case of the sprawl of diesel electricity generators in Beirut.

Lebanon, plagued by political and economic crises, experienced a government collapse in early 2020, leading to an electrical nationwide blackout by 2023. Diesel generators were used to compensate for the absence of power production from the national provider, Electricité du Liban (EDL). To investigate the effect of the crisis on the levels of 16 EPA particle bound polycyclic aromatic hydrocarbons (PPAHs), an annual comparative analysis of three locations within Beirut started in 2022 and ended in 2023.

Enhancement of Benzene Emissions in Special Combinations of Electronic Nicotine Delivery System Liquid Mixtures.

Electronic nicotine delivery systems (ENDS) are battery-powered devices introduced to the market as safer alternatives to combustible cigarettes. Upon heating the electronic liquid (e-liquid), aerosols are released, including several toxicants, such as volatile organic compounds (VOCs). Benzene has been given great attention as a major component of the VOCs group as it increases cancer risk upon inhalation.

Influence of nicotine form and nicotine flux on puffing behavior and mouth-level exposure to nicotine from electronic nicotine delivery systems.

Background: Nicotine form (freebase/protonated) and nicotine flux (rate at which nicotine is emitted) are two factors that can affect the dose of nicotine inhaled by individuals using electronic nicotine delivery systems (ENDS) because they can influence puffing behavior. The nicotine dose for each puff also is directly proportional to nicotine flux (i.e.

Effects of Aftermarket Electronic Cigarette Pods on Device Power Output and Nicotine, Carbonyl, and ROS Emissions.

Aftermarket pods designed to operate with prevalent electronic nicotine delivery system (ENDS) products such as JUUL are marketed as low-cost alternatives that allow the use of banned flavored liquids. Subtle differences in the design or construction of aftermarket pods may intrinsically modify the performance of the ENDS device and the resulting nicotine and toxicant emissions relative to the original equipment manufacturer's product. In this study, we examined the electrical output of a JUUL battery and the aerosol emissions when four different brands of aftermarket pods filled with an analytical-grade mixture of propylene glycol, glycerol, and nicotine were attached to it and puffed by machine.

Nontargeted Analysis in Tobacco Research: Challenges and Opportunities.

Tobacco products are evolving at a pace that has outstripped tobacco control, leading to a high prevalence of tobacco use in the population. Researchers have been tirelessly developing suitable techniques to assess these products' emissions, toxicity, and public health impact. The nonclinical testing of tobacco products to assess the chemical profile of emissions is needed for evidence-based regulations.

Nicotine flux as a powerful tool for regulating nicotine delivery from e-cigarettes: Protocol of two complimentary randomized crossover clinical trials.

Introduction: Electronic cigarette (EC) use has increased rapidly in the last decade, especially among youth. Regulating nicotine delivery from ECs could help curb youth uptake and leverage EC use in harm reduction yet is complicated by varying device and liquid variables that affect nicotine delivery. Nicotine flux, the nicotine emission rate, is a parameter that incorporates these variables and focuses on the performance rather than the design of an EC.

A Quick Method for the Determination of the Fraction of Freebase Nicotine in Electronic Cigarettes.

Recently, many electronic cigarettes (ECIGs) manufacturers have begun offering e-liquids, known as "nicotine salts". These salts that have started gaining big popularity among users can be formed by adding weak acid to e-liquid mixtures consisting of propylene glycol (PG), vegetable glycerin (VG), flavors, and nicotine. The latter can exist in two forms: monoprotonated (mp) and freebase (fb) based on the pH of the matrix.

Comparison of design characteristics and toxicant emissions from Vuse Solo and Alto electronic nicotine delivery systems.

Introduction: Vuse Solo is the first electronic nicotine delivery system (ENDS) authorised by the US Food and Drug Administration for marketing in the USA. Salient features of the Vuse Solo product such as nicotine form, draw resistance, power regulation and electrical characteristics have not been reported previously, and few studies have examined the nicotine and other toxicant emissions of this product. We investigated the design characteristics and toxicant emissions of the Solo as well as Alto, another Vuse product with a greater market share than Solo.

A Systematic Review of Analytical Methods for the Separation of Nicotine Enantiomers and Evaluation of Nicotine Sources.

The introduction of synthetic nicotine by the tobacco industry, also promoted as tobacco-free nicotine, presented new challenges for analytical chemists working in tobacco regulatory science to develop and optimize new methods to assess new nicotine parameters, namely enantiomer ratio and source. We conducted a systematic literature review of the available analytical methods to detect the nicotine enantiomer ratio and the source of nicotine using PubMed and Web of Science databases. Methods to detect nicotine enantiomers included polarimetry, nuclear magnetic resonance, and gas and liquid chromatography.

Acute effects of flavored Black and mild cigars among young adult cigarette smokers.

The U.S. Food and Drug Administration proposed new product standards that would ban characterizing flavors (other than tobacco) in cigars.

Impact of smoking intensity and device cleaning on IQOS emissions: comparison with an array of cigarettes.

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.

Did JUUL alter the content of menthol pods in response to US FDA flavour enforcement policy?

Background: The JUUL electronic cigarette (e-cigarette) remains popular in the USA and has a big prevalence among youth. In response to the popularity of JUUL and similar devices among youth, the US Food and Drug Administration issued in February 2020 an enforcement policy to remove all flavoured cartridge/pod-based e-cigarettes from the market except for tobacco and menthol. Subsequent studies showed that some users of the now-removed flavoured JUUL pods (especially cool mint) switched to menthol-flavoured JUUL pods with similar satisfaction.

Assessing toxicant emissions from e-liquids with DIY additives used in response to a potential flavour ban in e-cigarettes.

Significance: Electronic cigarettes (e-cigarettes) aerosolise liquids that contain nicotine, propylene glycol, glycerol and appealing flavours. In the USA, regulations have limited the availability of flavoured e-cigarettes in pod-based systems, and further tightening is expected. In response, some e-cigarette users may attempt to make their e-liquids (do-it-yourself, DIY).

Electrical features, liquid composition and toxicant emissions from 'pod-mod'-like disposable electronic cigarettes.

Introduction: Use of flavoured pod-mod-like disposable electronic cigarettes (e-cigarettes) has grown rapidly, particularly among cost-sensitive youth and young adults. To date, little is known about their design characteristics and toxicant emissions. In this study, we analysed the electrical and chemical characteristics and nicotine and pulmonary toxicant emission profiles of five commonly available flavoured disposable e-cigarettes and compared these data with those of a JUUL, a cartridge-based e-cigarette device that pod-mod-like disposables emulate in size and shape.

JUUL 'new technology' pods exhibit greater electrical power and nicotine output than previous devices.

In 2019, JUUL Labs began marketing in the European Union 'new technology' pods that incorporated a new wick that it claimed provided 'more satisfaction'. In this study, we compared design and materials of construction, electrical characteristics, liquid composition and nicotine and carbonyl emissions of new technology JUUL pods to their predecessors. Consistent with manufacturer's claims, we found that the new pods incorporated a different wicking material.

Effect of free-base and protonated nicotine on nicotine yield from electronic cigarettes with varying power and liquid vehicle.

Nicotine in electronic cigarette (ECIG) liquids can exist in a free-base or protonated (or "salt") form. Protonated nicotine is less aversive upon inhalation than free-base nicotine, and many ECIG manufacturers have begun marketing protonated nicotine products, often with high nicotine concentrations. Regulations intended to control ECIG nicotine delivery limit nicotine concentration but do not consider nicotine form.

Vaped Humectants in E-Cigarettes Are a Source of Phenols.

Electronic cigarettes (ECIGs) have always been promoted as safer alternatives to combustible cigarettes. However, a growing amount of literature shows that while ECIGs do not involve combustion-derived toxicants, thermal degradation of the main constituents of ECIG liquid produces toxicants such as carbonyls. In this study, we report the detection of phenolic compounds in ECIG aerosols using a novel analytical method.

Hot Wires and Film Boiling: Another Look at Carbonyl Formation in Electronic Cigarettes.

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.

Might limiting liquid nicotine concentration result in more toxic electronic cigarette aerosols?

Some jurisdictions have instituted limits on electronic cigarette (ECIG) liquid nicotine concentration, in an effort to control ECIG nicotine yield, and others are considering following suit. Because ECIG nicotine yield is proportional to the product of liquid nicotine concentration (milligram per millilitre) and device power (watts) regulations that limit liquid nicotine concentration may drive users to adopt higher wattage devices to obtain a desired nicotine yield. In this study we investigated, under various hypothetical regulatory limits on ECIG liquid nicotine concentration, a scenario in which a user of a common ECIG device (SMOK TF-N2) seeks to obtain in 15 puffs the nicotine emissions equivalent to one combustible cigarette (ie, 1.

Impact of flavors and humectants on waterpipe tobacco smoking topography, subjective effects, toxicant exposure and intentions for continued use.

Introduction: The present study examined how the lack of characterising flavours and low levels of humectants may affect users' waterpipe tobacco (WT) smoking topography, subjective effects, toxicant exposure and intentions for continued use.

Methods: 89 WT smokers completed four ad libitum smoking sessions (characterising flavor/high humectant (+F+H); characterising flavor/low humectant (+F-H); no characterising flavor/high humectant (-F+H); no characterising flavor/low humectant (-F-H)) in a randomised cross-over design. WT was commercially available; same brand but nicotine levels were not held constant.

A comparison of the electrical characteristics, liquid composition, and toxicant emissions of JUUL USA and JUUL UK e-cigarettes.

In 2018, JUUL entered the UK market, where EU regulations limit liquid nicotine concentration to 20 mg/mL, approximately one-third the level of JUUL products sold in the USA. We hypothesized that JUUL's UK product was engineered to deliver greater electrical power and boost liquid vaporization such that the net nicotine delivery rate was similar to the US version. We compared electrical characteristics, liquid composition, and aerosol emissions of JUUL devices procured in the USA and the UK.

Comparison of CO, PAH, Nicotine, and Aldehyde Emissions in Waterpipe Tobacco Smoke Generated Using Electrical and Charcoal Heating Methods.

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.

Characteristics and toxicant emissions of JUUL electronic cigarettes.

Introduction: JUUL is an electronic cigarette (ECIG) with a compact form factor. It is prefilled with a liquid that is advertised to contain a high concentration of nicotine salt. JUUL commands 50% of the US ECIG market share, and its wide popularity with underage users has triggered unprecedented actions by the US FDA.

Carbon Monoxide and Small Hydrocarbon Emissions from Sub-ohm Electronic Cigarettes.

Electronic cigarettes (ECIGs) are routinely advertised as a safer alternative to combustible cigarettes. ECIGs have been shown to emit less toxicants than conventional cigarettes. This study presents for the first time the mouthpiece emissions of carbon monoxide (CO) and small hydrocarbon gases, in addition to carbonyls, from a rebuildable atomizer sub-ohm device (SOD).