Contributions to Tobacco & Nicotine Research Feed

Disposable E-Cigarettes and Metal Emissions: A Case Study of Corrosion-Related Artefacts and Implications for Toxicological Interpretation

Mon, 12 Oct 2026 00:00:00 GMT

E-liquids stocked inside unregulated disposable vaping devices are subjected to corrosion effects from their chemical interaction with metallic parts during their likely long-time storage. Consequently, aerosols generated from these e-liquids likely contain abundant yields of metallic elements, an outcome that becomes more plausible and concerning in the absence of quality control in large unregulated markets. In order to address the potential effects of corrosion in disposable devices, we considered the wealth of experimental data obtained in a recently published article (1) that thoroughly quantified metallic elements in e-liquids and aerosols of three brands of unregulated but popular disposable devices (3 ELF Bar, 2 Flum Pebble, and 2 ESCO Bar). Nickel levels steadily increased as all devices were puffed in sequences of 100 puffs up to 1,500 puffs, while the ESCO Bar and Flum Peeble respectively exhibited high levels of lead and antimony. However, the authors also report high levels of these metals in e-liquids of the devices already before testing them. Using the authors’ own data, we highlight that these experimental results are consistently explained by corrosion effects in e-liquids kept inside devices stored in the likely long-time between their manufacture and their testing. Without considering this initial defective state the authors presented incomplete comparisons of their results with those of other vaping devices (refillable and cartridge based) and with tobacco smoke. We also show that the authors overestimated cancer and non-cancer risks by assuming an unrealistic lifetime risk model and for failing to account for the appropriate exposure scenario inherent in vaping. Our results might highlight the pressing necessity to regulate and implement quality control standards to the whole class of disposable vaping devices.

Prediction Model for the Filtration of Smoke Aerosol Particles by Cellulose Acetate Filters

Mon, 12 Oct 2026 00:00:00 GMT

Exploring the filtration characteristics of smoke aerosol particles in cellulose acetate filters and developing a prediction model are vital for designing cigarettes with low “tar” and harmful components. This study employed solanesol as a marker for smoke aerosol particles to investigate its filtration performance in cellulose acetate filters. The effects of length, pressure drop, tow specifications, and flow velocity on the filtration of smoke aerosol particles by cellulose acetate filters were analyzed using an HPLC-DAD method. The results indicated that the filtration of smoke aerosol particles by cellulose acetate filters conformed to the first-order kinetic filtration equation. For filters with the same circumference, the filtration coefficient of smoke aerosol particles was linearly proportional to the pressure drop per unit filter length. Moreover, the tow specifications had no significant effect on the filtration of smoke aerosol particles. The filtration coefficient of smoke aerosol particles decreased with increasing flow velocity. Based on these characteristics, a prediction model for the filtration of smoke aerosol particles by cellulose acetate filters was established, incorporating flow velocity, pressure drop per unit filter length, and circumference. This model was employed to predict the filtration coefficients of smoke aerosol particles in different filters, achieving prediction deviations of less than 5%. Applying the model to predict the filtration efficiencies of “tar” in different filters, the prediction deviations were below 15%. The model can accurately predict the filtration efficiencies of particulate matter in cellulose acetate filters, which provides technical support for cigarette harm reduction, and also offers valuable references for aerosol particles filtration in the atmospheric and industrial fields.

Identifying Reliable Labeling Comprehension Questions for E-Vapor and Heated Tobacco Products: A Meta-Analytic Approach

Fri, 18 Sep 2026 00:00:00 GMT

BackgroundLabeling comprehension research can be tedious and resource-constraining because it often involves iterative reliability assessments of relevant metrics (e.g., formative testing of any safety or product-use related questions), leading to increased time requirements and shrinking sample pools in the population of interest. The goal of this work was to temper the need for formative metric evaluations in labeling comprehension research by identifying labeling comprehension questions that: 1) can be reliably answered correctly and 2) are generalizable across research on electronic nicotine delivery system (ENDS) products and heated tobacco products (HTPs). We explored whether, across four labeling comprehension studies for three distinct nicotine products (one ENDS, two HTPs), we could meta-analytically identify labeling comprehension questions that consistently demonstrated high correct response rates (relative to a 100% correct response rate).MethodsForty-five relevant questions were identified across studies and were categorized into 13 groups/domains for analysis purposes. Correct response rates for questions within a group/domain were analyzed using a proportional meta-analysis. A proportional meta-analysis is a data-synthesis method that allows for the calculation of a pooled overall proportion from multiple individual proportions (1).ResultsEvidence from six of the tested domains (‘Know to charge device only with proprietary accessories,’ ‘Know to not expose device to high temperatures,’ ‘Know to not use device if it becomes wet or immersed in a liquid,’ ‘Know to not use device if it appears damaged or broken,’ and ‘Know not to use the device with other manufacturer's items’) indicates that if the domain-specific question were asked again in a future study, a high proportion of participants would be expected to answer the question correctly. These six domains can serve as benchmarks for crafting questions that engender high correct response rates for the evaluated question domains. Five question domains (‘Know to not use device if it is operating in a strange manner,’ ‘Know that the device contains nicotine,’ ‘Know how long the tobacco consumable will last,’ ‘Know not to use the device if the battery behaves unexpectedly,’ and ‘Know that the product contains tobacco’) generally displayed high pooled proportions and narrow confidence intervals (but wide prediction intervals), indicating robust utility in crafting similar question for new studies, albeit context specific adjustments would help bolster the likelihood of high correct response proportions. Data for the two remaining domains (‘Know to keep device away from children,’ and ‘Know how many times you can use the tobacco consumable’) indicated wide variability in correct response proportions, thus questions from these domains would likely require significant context-based adaptation in future studies to engender high correct response proportions.ConclusionsThis work provides evidence that labeling research can be analytically leveraged to ease the burdens of new research; in this case, facilitating labeling comprehension research by meta-analytically demonstrating correct response consistency across varied question domains, thus providing design resources for researchers who are crafting labeling questions and user guides/safety guides.

Methodology Differences Impacting Prevalence Estimates of Youth Use of Electronic Nicotine Delivery Systems (ENDS) across Waves 5–7 of the Population Assessment of Tobacco and Health

Tue, 08 Sep 2026 00:00:00 GMT

BackgroundThe Population Assessment of Tobacco and Health (PATH) is a commonly-used longitudinal survey on nicotine/tobacco product use meant to represent the US population. Accurate surveillance to prevent youth electronic nicotine delivery systems (ENDS) use requires understanding the impact of methodological differences in Wave 6 (∼2021), specifically older ages (14–17 vs. usual 12–17) and survey mode (some telephone interviews vs. usual self-completed).MethodsChanges in past-30-day (P30D) youth ENDS prevalence and patterns of use (i.e., frequency, device type, flavors, and brand) were examined year-over-year and for the 3-year period (2019–2022). Analyses compared combined age groups and survey modes (i.e., among all youth in each wave regardless of methodological differences) with methodologically-comparable sub-groups (i.e., same age range and survey mode). The impact of age on point estimates and trends (i.e., interaction with wave) was examined.ResultsYouth P30D ENDS prevalence significantly declined over the prior 3 years, but not year-over-year in either the naïve or methodologically-comparable analyses. However, 14–17-year-olds reported higher prevalence and steeper declines (age-wave interaction p < 0.0001) over the past 3 years (12.2% to 7.5%) than 12–13-year-olds (1.7% to 1.2%). Age differences had more modest impacts on patterns of ENDS use.DiscussionMethodological differences in PATH Wave 6 introduced artifacts in estimates of prevalence, and to a lesser extent, patterns of youth ENDS use. Waves 5 and 7 are approximately comparable (∼95% equivalent) with respect to these differences. Future research examining prevalence trends over these waves should account for differences in survey mode and age range.

Nicotine Is Not a Proinflammatory Component of E-cigarette Vapor

Mon, 31 Aug 2026 00:00:00 GMT

Cigarette smoking is causally associated with a number of chronic diseases in which inflammation plays an important pathogenic role including pulmonary carcinoma, chronic bronchitis, emphysema, atherosclerosis, and thrombosis. In addition, cigarette smoking can exacerbate Crohn's disease and rheumatoid arthritis. In both the particulate and vapor phases, cigarette smoke contains a number of chemicals with proinflammatory or cytotoxic potential. In contrast with cigarette smoking, nicotine has been shown to ameliorate several inflammatory conditions via activation of α7- and α9-nicotinic cholinergic receptors. The chemistry of electronic cigarette (e-cigarette) vaping aerosols is comprised mainly of glycerol, propylene glycol, nicotine, and flavors. The nicotine can be found in either the free base or salt forms depending on the particular product design. E-cigarettes containing nicotine salts have the potential for nicotine exposure levels higher than cigarettes as the sensory cues associated with tobacco smoke nicotine (containing a mixture of free base nicotine and nicotine salts) have been dampened. In this review and analysis, the role of nicotine in inducing inflammation in the absence of other main-stream cigarette smoke constituents is examined. Established and putative mechanisms by which nicotine influences inflammatory pathways in users of nicotine-containing products are described toward better understanding nicotine's potential contribution to the risk profile. For the majority of diseases with an inflammatory component induced by cigarette smoking, evidence suggests that nicotine is not the causative agent. E-cigarette aerosols should limit the diversity of chemical constituents and minimize exposure to proinflammatory chemicals, e.g., acrolein, acetaldehyde, formaldehyde, and heavy metals.

Interlaboratory Comparison of Particle Size Analysis Methods for Dry and Wet Nicotine Pouch Fillers: A Proficiency Testing Study

Wed, 08 Jul 2026 00:00:00 GMT

Particle size distribution (PSD) is a key parameter in understanding the physical characteristics of nicotine pouch products. This study presents the results of a proficiency testing (PT) study conducted across eight laboratories (Labs 1–8) to assess the consistency and accuracy of particle size analysis methods for four commercially available nicotine pouch filler samples, two dry (CP1 and CP3) and two wet (CP2 and CP4). Three analytical techniques were employed: sieving, dynamic image analysis (DIA), and laser diffraction. The study aimed to evaluate inter-laboratory variability and method comparability, providing insights into the most suitable techniques for different nicotine pouch filler types. Four laboratories used sieving, two laboratories used dynamic image analysis, and two laboratories used laser diffraction, providing particle size distributions and distribution intercepts at 10%, 50%, and 90% (Dx[10], Dx[50], and Dx[90]). Sieving showed consistent Dx[50] results across laboratories but was inefficient for high sample volumes and unsuitable for wet samples. DIA, while offering high sensitivity and detailed shape characterization, exhibited significant inter-laboratory variability due to differences in shape parameters and sample introduction methods. Laser diffraction provided rapid measurements with a broad dynamic range, suitable for both wet and dry samples, though it requires accurate refractive index and non-fibrous samples. Statistical analysis revealed significant differences within and between methods, particularly for Dx[10] and Dx[50] values. For dry products, sieving yielded similar Dx[50] values (315.3 μm to 325.4 μm for CP1), while DIA showed larger differences (327.66 μm to 381.14 μm for CP1). Laser diffraction showed good consistency, especially for wet samples, with low percent differences (1.9% for CP2 Dx[90]). The study underscores the importance of method selection based on sample nature, desired sensitivity, and application requirements, with sieving showing consistency for dry products, laser diffraction being robust for wet samples, and DIA valuable for shape characterization. The results support the development of standardized protocols for PSD analysis in nicotine pouch formulations, fostering better understanding in the development of these products.

Systematic Investigation of Migration and Decay Characteristics of Sweeteners in Cigarette Tipping Paper: Kinetics, Mechanisms, and Stability Implications

Sat, 20 Jun 2026 00:00:00 GMT

The stability of sweeteners in cigarette tipping paper is critical for cigarette product quality but remains under-explored. This study systematically investigated the decay behaviors of five synthetic sweeteners (acesulfame, sodium saccharin, sucralose, neotame, and aspartame) from three classes (sulfonamides, dipeptides, and sucrose derivatives). Using a validated HPLC-MS/MS method, we quantified the effects of time, temperature, and composition (mono-/hybrid-component). At room temperature, mono-component sweeteners exhibited rapid decay within 30 days, followed by a plateau. Decay rates initially followed the order: sulfonamides > sucralose > dipeptides, correlating with their initial transfer rates. Elevated temperature accelerated decay for all sweeteners, with sucralose and aspartame showing the highest sensitivity. Notably, hybrid-sweetener formulations demonstrated superior stability in maintaining sweetness perception. To elucidate the underlying mechanisms, four kinetic models were employed to fit the experimental data, providing insights into the decay processes. Based on these systematic findings, practical guidelines for the rational selection and shelf-life prediction of sweeteners in tipping paper were established. This work provides fundamental chemical behavior data and generalized guidance for ensuring the long-term stability of sweetened tobacco products.

Puffing Topography, Mouth Level Exposure, Average Daily Consumption and Machine Emissions of Three Variants of glo™ Heated Tobacco Products Among UK Smokers

Sat, 20 Jun 2026 00:00:00 GMT

Heated tobacco products (HTPs) typically expose consumers to significantly reduced toxicant emissions relative to conventional cigarettes, when measured under machine-generated conditions. As HTPs evolve in design and new consumables are introduced, it is essential to assess whether these changes affect how consumers use HTPs and thus their potential exposure to toxicants in the aerosol. The objective of this study was to assess whether changes in tobacco flavour or nicotine content of HTP consumables influenced consumers' use behaviour and exposure. Here, puffing topography, average daily consumption (ADC) and mouth-level exposure (MLE) to nicotine and nicotine-free dry particulate matter (NFDPM) were measured among 72 healthy adult cigarette smokers in the UK. Participants used a Type 1 HTP device (glo™) with three consumables: a base consumable (Bright Tobacco flavour, 0.85% nicotine) previously indicated with the glo™ device to support a reduced risk profile relative to conventional cigarettes; Variant 1 (Rich Tobacco flavour, 0.85% nicotine); and Variant 2 (Rich Tobacco flavour, 1.5% nicotine). The respective machine-generated aerosols were also analysed for nine toxicants. In a two-week randomised crossover study, participants used each study product for five days at home, while recording daily product use. Their puffing topography and MLE were then measured using a desktop-based puffing analyser device (SA7) at a central location testing facility. Differences in puffing behaviour and ADC for both variant consumables were either smaller than predefined analytical thresholds, or were within predefined equivalence margins (0.80–1.25 and 90% confidence intervals of mean ratio), with the exception of effort for Variant 2, and therefore puffing behaviour and ADC were considered equivalent to the base consumable. Differences in MLE for Variant 1 were either smaller than the predefined analytical thresholds, or within the predefined equivalence margins. For Variant 2, differences in MLE to NFDPM were smaller than the predefined analytical thresholds, however MLE to nicotine was higher relative to the base consumable (0.40 vs. 0.29 mg/stick), and did not fall within the equivalence margins, consistent with the higher nicotine content in this variant. Under the conditions of this study, variations in flavour and nicotine concentration did not lead to significant changes in measures of user behaviour or NFDPM exposure.

Widespread Misperception of Relative Risks of ENDS versus Cigarette Smoking among Key Populations for Tobacco Harm Reduction in a 2022 Representative U.S. Sample

Sun, 03 May 2026 00:00:00 GMT

ObjectiveTobacco harm reduction (THR) using represents a pragmatic and realistic strategy, to which electronic nicotine delivery systems (ENDS) misperceptions act as a barrier. This paper explores ENDS misperceptions, especially among certain groups disproportionately affected by smoking.MethodsUsing the Population Assessment of Tobacco and Health (PATH) Wave 7 (2022), key populations for THR were identified as 3,481 adults who exclusively smoke (AWES) and who are not planning to quit within 30 days (NPQ), 56% of whom were male. Non-White racial/ethnic groups, male, ages ≥ 55, high school/GED or less education, household income < $25,000, non-heterosexual, and AWES with fair or poor mental health were characterized as subpopulations disproportionately affected by smoking. Misperception was defined as perceiving ENDS to be at least as harmful as cigarettes.ResultsNinety-four percent of AWES-NPQ had ENDS misperceptions. While misperceptions were > 91% in all sub-groups, the odds of reporting misperceptions were higher among: Black respondents (vs. White, OR = 1.79 [95% CI = 1.13–2.83]), those aged ≥ 55 (vs. < 55, 1.47 [1.02–2.12]), and AWES with high school or less education (vs. at least some college, 2.10 [1.47–3.01]. Conversely, male AWES had reduced odds of having ENDS misperceptions (vs. female, 0.55 [0.38–0.80]).ConclusionsENDS misperceptions were highly prevalent among AWES-NPQ, and some subgroups disproportionately affected by smoking were even more likely to hold misperceptions. Efforts to reduce smoking disparities could be enhanced by communicating ENDS' reduced-risk potential, which could encourage AWES to adopt ENDS and completely switch away from smoking.

Natural Tobacco Flavor Profiling Under Heat-Not-Burn Conditions Using Reference Tobacco Leaves and Tobacco from 1R6F Reference Cigarettes

Thu, 30 Apr 2026 00:00:00 GMT

Studying the organoleptic properties of heated tobaccos in relation to natural flavors is essential for understanding how lower-temperature processing influences the release of intrinsic tobacco flavor compounds. Unlike combustion processes (> 600 °C), which generate numerous undesirable substances, the heat-not-burn approach (< 350 °C) helps preserve the integrity of natural terpenoids, alkaloids, phenols, and other bioactive molecules while reducing harmful byproducts. This research studied which natural flavor compounds are released from different tobacco types when heated at temperatures typical of heated tobacco products (HTPs) and how these compounds likely contribute to the flavor and aroma profiles. No preliminary modifications were made to the tobacco samples. Four tobacco types were selected: flue-cured, Oriental, Burley, and dark air-cured. The ground lamina of these tobaccos, along with filler from reference 1R6F cigarettes (all provided by the Center for Tobacco Reference Products), were analyzed. Gas Chromatography–Mass Spectrometry (GC-MS) analysis was performed using a Thermal Separation Probe (TSP), which thermally desorbed volatile and semi-volatile constituents from the ground leaf materials at controlled inlet temperatures (200–325 °C). The released compounds were directly introduced into the GC inlet for chromatographic separation and subsequent mass spectrometric identification. Among the numerous peaks detected, flavor-like compounds previously identified in the literature were selected for further evaluation. Flue-cured tobacco yielded 16 identified flavor compounds, oriental tobacco 21, burley 15, and dark air-cured 15. Sixteen compounds were detected in the reference 1R6F cigarette sample. In total, 32 natural flavor compounds were identified across the five tobacco samples. Flavor properties of each compound were assigned based on various literature sources. Compounds were also categorized by chemical class and compared across the five tobacco types. Based on this class-wise distribution, the natural organoleptic profile of each tobacco type was estimated. Several natural compounds were detected that have not previously been reported in aerosols generated from heated tobacco products at low temperatures (200–325°C). These compounds may potentially expand the flavor profile of heated tobacco products.

Operating Conditions of an Induction-Based Electrically Heated Tobacco System – Tobacco Heating System 3.0

Wed, 25 Mar 2026 00:00:00 GMT

In the last decade, tobacco products intended for inhalation without combustion have emerged as alternatives to cigarettes. Tobacco Heating System (THS) 3.0 is an induction heating device combined with specially designed electrically heated tobacco products that offers an improved product performance consistency throughout the device lifecycle and a cleaner user-experience than previous THS versions, which rely on direct heating technologies. THS 3.0 has previously been assessed to emit significantly fewer and lower levels of harmful constituents than cigarettes, resulting in an aerosol with reduced in vitro cytotoxicity and genotoxicity compared to cigarette smoke. In this paper, a rigorous assessment substantiates that no combustion occurs during THS 3.0 operation and that its emission is a liquid-based aerosol that is not smoke, as there is: 1) no ignition, 2) net endothermic degradation, 3) no ash formed, 4) comparable emissions in oxidative and non-oxidative atmospheres, 5) CO/CO2 ratio typical for when tobacco is heated and not combusted, and 6) no carbon-based solid particles generated. In addition, THS 3.0 satisfies the absence of combustion criteria of mandatory and voluntary product standards issued by national standardization bodies.

Impact of HPLC Parameters on Chiral Separation of Nornicotine Enantiomers

Thu, 19 Mar 2026 00:00:00 GMT

Given the well-documented pharmacological differences between nicotine and nornicotine enantiomers, understanding their distribution is essential. This knowledge also helps authenticate the enantiomers’ source (natural or synthetic). To improve the quantitative determination methods for these distributions, the influence of additives, modifiers, and sample matrices on the chiral HPLC separation of the nornicotine enantiomers using UV detection is discussed. Changes on the order of 5–10% in selected alcohols as modifiers and selected amines (0.1% changes) as additives were found to have significant effect on the resolution and retention times of nornicotine enantiomers, while sample matrices demonstrated an impact on nornicotine enantiomer resolution (R). Systematic variation in the concentration of ethanol and isopropanol, as modifiers, along with variations in the concentration of diethylamine, triethylamine, and isopropylamine, as additives, revealed that the resolution (R) of the nornicotine enantiomers could be adjusted to values much greater than 2, using mobile phase flow rates of 0.8 and 1 mL/min. The retention times of the nornicotine enantiomer pairs could be varied between ~8 and 20 min, through modification of the mobile phase with the additives and modifiers. As expected, faster mobile phase flow rates of 1 mL/min moderately reduced retention times when compared with influences on retention time caused by changes in the amounts of modifier and additive, with an accompanying slight decrease in the R values. The %RSD values for both nornicotine resolution and retention times consistently remained below 3%. The detection limits for the nornicotine enantiomers were approximately 1 ng on column for each enantiomer. With the judiciously selected optimization of the levels of the hexane mobile phase additive, diethylamine, and modifier, ethanol, coupled with results from previously published results on nicotine and nornicotine alkaloid enantiomer separations, a simultaneous separation of both nornicotine and nicotine enantiomers having R values greater than 2 and an overall retention time of less than 15 min was attained. Noticeable influences on nornicotine enantiomer resolution and co-elution of tobacco extract components with nornicotine enantiomers as a function of mobile phase composition were illustrated and discussed. Previous published results in combination with this current body of work culminate in a well-rounded understanding of the influences of modifier and additive structure and concentration on the resolution as well as a simultaneous separation of nicotine and nornicotine enantiomers employing high performance liquid chromatography.

CORESTA Guidelines for Descriptive Consumer-Reported Outcome Measures in Tobacco and Nicotine Research

Wed, 25 Feb 2026 00:00:00 GMT

IntroductionDescriptive Consumer-Reported Outcome Measures (CROM) are self-reported survey outcome measures intended to measure observable characteristics and behaviors in research on tobacco- and nicotine-containing products (TNPs). The wide variety of available TNPs and the continued development of new TNPs require a constant evolution of measures to assess TNP use and related constructs adequately. The guidelines aim to provide recommendations on the selection, development, implementation, and analysis of Descriptive CROM in research on TNPs.MethodsThe best practices and guidelines on Descriptive CROM were developed via an iterative and consensus-driven approach by the Descriptive CROM working group within the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) CROM Task Force. This involved reviewing relevant national and international surveys, peer-reviewed publications, publicly available guidelines, and best practices published by professional institutes in related fields. The Descriptive CROM working group also collaborated with other CORESTA subgroups and relevant subject matter experts representing public health, academia, and the tobacco industry to continuously update the guidelines.ResultsThe resulting guidelines contain four main sections. First, we introduce the Descriptive CROM domain framework and provide definitions and descriptions of TNP categories and use patterns. Second, based on review of existing Descriptive CROM from national and international surveys, recommendations on Descriptive CROM for TNP research are provided. Third, the guidelines provide recommendations related to the development, modification, and adaptation of Descriptive CROM. This section includes a multi-stage process for CROM development, including item generation and qualitative and quantitative assessments of the CROM. The final section on Descriptive CROM implementation includes recommendations for best practices from the CORESTA organization for study design and development, data analysis, and reporting of Descriptive CROM data.ConclusionsThe recommendations on the development, modification, and application of Descriptive CROM are grounded in scientific rationale and developed with consensus from the CORESTA TNP research community. The consensus Descriptive CROM measures, along with consistent definitions, could facilitate comparisons across studies, aggregation of data sets, and improve harmonization in research findings. As best practices and guidelines may evolve over time, the CORESTA CROM Task Force will continue to update the guidelines based on the dynamic TNP landscape and regulatory requirements to advance TNP research.

Anne Fisher, Recipient of the 2025 Tobacco Science Research Conference Lifetime Achievement Award

Mon, 29 Dec 2025 00:00:00 GMT

Critical Appraisal of Exposure Studies of E-Cigarette Aerosol Generated by High-Powered Devices*

Mon, 29 Dec 2025 00:00:00 GMT

Currently low-powered pods and disposables overwhelmingly dominate consumer preference of vaping products. Yet, despite its marginal usage, third generation high power low resistance (sub-ohm) devices are still used frequently to generate aerosols for assessing the toxicity of vaping aerosols. All these studies operate these devices under the CORESTA Recommended Method 81 protocol or with slight modifications, with airflow rates around 1 L/min. This experimental set up is concerning, since we have published various articles showing that much higher airflow rates (around 10 L/min) are a necessary experimental condition for these devices to generate aerosols that avoid overheating and large production of toxic byproducts. In a previous recent article, we replicated aerosol generation from a high-powered device integrated into a computerized exposure system used to expose in in vitro and in vivo systems. After careful calibration, we identified the experimental conditions for this device to avoid generating aerosols under an Overheating Regimen that would generate a repellent aerosol for human users. Applying the experimental results of this study, we show in this critical review that all studies using this same device exposed biological systems to overheated and aldehyde-loaded aerosols, with about half of the studies also delivering excessive nicotine concentrations. Some studies reported the presence of carbon monoxide, suggesting evidence of advanced wick pyrolysis. Most of the reviewed studies are irreproducible for failing to provide sufficient information of their aerosol generation procedures. Our results raise questions on the relevance of this literature to assess the risk profile of vaping products. Finally, we provide guidelines to improve the protocols of aerosol generation methodology in emission and exposure studies. [Contrib. Tob. Nicotine Res. 34 (2025) 202–221]

Determination of NOx in Mainstream Cigarette Smoke, CORESTA Collaborative Study and Recommended Method

Mon, 29 Dec 2025 00:00:00 GMT

A collaborative study among twelve laboratories was conducted to establish a recommended method for determination of oxides of nitrogen (NOx) in mainstream cigarette smoke. Three cigarette samples, with ISO 3308 total particulate matter yields ranging from 2–17 mg/cig, were evaluated under both a non-intense (ISO 3308) and an intense (ISO 20778) smoking regime to assess the method’s applicability across a range of conditions. Mainstream cigarette smoke was either passed through an in-line detector or collected in a gas-tight system for offline determination of NOx by chemiluminescence. Optional use of glass fiber filter pads enabled gravimetric determination of total particulate matter. Statistical analyses were performed according to ISO 5725 to determine repeatability (r) and reproducibility (R), and z-scores. Reproducibility, expressed as a percentage of mean yield across all products, smoking regimes, and analysis types, ranged from 15.1–49.7%. NOx yields ranged from 71–437 μg/cig and followed expected trends with respect to total particulate matter and smoking intensity. These results demonstrate the robustness of the proposed method and support its adoption as CORESTA Recommended Method CRM N° 104. [Contrib. Tob. Nicotine Res. 34 (2025) 222–229]

Indoor Air Quality Assessment During the Use of Tobacco and Nicotine Products*

Mon, 29 Dec 2025 00:00:00 GMT

Chemical toxicants released into the environment during the use of tobacco and nicotine products potentially give rise to an elevated health risk among non-users. The aim of this study was to assess the levels of a wide range of chemical toxicants in the indoor air of an unventilated testing facility during various scenarios of tobacco and nicotine product use, including the use of conventional waterpipes, electronic vaping products (EVPs, also known as e-cigarettes), an electronic waterpipe which uses electrical heating of shisha tobacco instead of conventional charcoal heating, and combustible-cigarettes. In the one-occupant scenarios, increases in PM10 and PM2.5 were greatest during conventional waterpipe use, approximately 40% lower for OOKA electronic waterpipe use, and lowest for EVP use. An increase in the combustion by-product CO was greatest for conventional waterpipe use, and substantially lower for EVP and OOKA electronic waterpipe use, with the latter generating only a negligible amount of CO. The increase in formaldehyde levels was greatest for conventional waterpipe use, and substantially lower for OOKA electronic waterpipe use. In ten-occupant product use scenarios, increases in PM10 and PM2.5 were greatest for EVP use and slightly lower for OOKA electronic waterpipe use, lower during the cigarette smoking scenario, and lowest for the unattended conventional waterpipes scenario. Increases in CO and formaldehyde were highest for the conventional waterpipes scenario, substantially lower during cigarette smoking, and negligible for OOKA electronic waterpipe and EVP use. Increases in several other volatile organic compounds and some polycyclic aromatic hydrocarbons were mainly seen only during cigarette smoking and were negligible during the other product use scenarios. This pattern was similar for the tobacco-specific nitrosamines NNN, NNK, and NAT. These findings have important implications concerning the potential for secondhand toxicant exposure among waterpipe non-users, and for understanding how to potentially reduce health risks associated with such exposure. [Contrib. Tob. Nicotine Res. 34 (2025) 230–241]

Exploring Safer Smoke-Free Alternatives to Conventional Cigarettes for a Healthier Tomorrow

Tue, 11 Nov 2025 00:00:00 GMT

Tobacco cigarette smoking continues to be the global leading cause of morbidity and mortality. Despite the awareness of its grave consequences, smokers find it extremely challenging to quit the addiction. A human-centric approach is crucial to fight against tobacco harm. Eventually, the global landscape of smoke-free alternative tobacco products like tobacco heating systems, electronic cigarettes, nicotine pouches and snus have significantly evolved. Unlike conventional cigarettes, these products except snus and nicotine pouches utilize heating instead of combustion, generating a less toxic aerosol. This mitigates the development of chronic obstructive pulmonary disease, lung cancer, cardiovascular and periodontal diseases. This review article elaborates the effectiveness, benefits and potential harm reduction of smoke-free alternative tobacco products associated with smoking cessation, biomarkers of exposure and health-related diseases in comparison to tobacco cigarettes. The controversial debate and related concerns of abuse liability and addiction among youth by smoke-free alternative products is explored. Creating awareness and management through better regulatory policies is crucial.

Influences of Airflow Pathway and Velocity on Aerosol Release Mechanisms in Granule-Based HTP

Tue, 11 Nov 2025 00:00:00 GMT

To investigate the effect of the airflow velocity on the mechanism through which aerosol is released in granule-based heated tobacco products (HTPs), experiments were conducted using two airflow pathways: open-ended and closed-ended configurations. The patterns of release of aerosol collected mass (ACM) and key aerosol components (nicotine, water, glycerol, and propylene glycol) and the distribution patterns of nicotine, glycerol, and propylene glycol in smoked cigarettes were measured. The results indicated that for the open-ended pathway, the airflow velocity did not strongly affect the total release amounts of ACM and its key components. The distribution of each component in the cigarette after it was smoked was also found to be relatively unaffected by the airflow velocity. However, for the closed-ended pathway, as the airflow velocity was decreased, the ACM and its total release amount decreased, and the residual amounts of each component in the tobacco granules and filter rod increased. In addition, the puff-by-puff release patterns of aerosols and their key components were different for the two airflow pathways. Specifically, for both pathways, the puff-by-puff ACM and water release gradually decreased after peaking quickly, whereas the levels of glycerol gradually increased, peaking at 7 or 8 puffs. The amounts of propylene glycol and nicotine first increased and then decreased for the open-ended pathway, reaching a peak at 4 or 5 puffs, whereas for the closed-ended pathway, these amounts gradually increased and peaked at 7 or 8 puffs. The aerosol particle size distribution results revealed that due to different processes of aerosol condensation and nucleation, as the airflow velocity was decreased, the aerosol number concentration and volume concentration decreased for both pathways but the median particle size increased. The closed-ended pathway resulted in a greater decrease or increase than did the open-ended pathway.

Effect of Propylene Glycol on Cigar Mainstream Smoke TNCO Yields

Tue, 11 Nov 2025 00:00:00 GMT

1,2-Propylene glycol (PG) is one of the most utilized humectants in the tobacco industry.The impact of PG on smoke yields has been extensively studied on cigarettes, but the results are still inconclusive, and, to our best knowledge, nothing has yet been published on the impact of PG on cigar smoke.In this study we investigate the effects of PG on cigar smoke yields, analyzing nicotine, carbon monoxide (CO), water and nicotine-free dry particulate matter (NFDPM or “tar”) content in mainstream smoke from different cigars. We performed a statistical retrospective analysis of four years of internal laboratory data of three cigar brands flavored with blends containing low, medium and high concentrations of PG.Furthermore, to avoid any interference other than PG, experimental cigars with only PG added were produced and analyzed.As for the retrospective analysis, smoke yields seem to be statistically related to tobacco PG content. Cigars with increasing amounts of PG show an increase in water and CO and a decrease in nicotine content. For NFDPM the trend seems quite ambiguous, since it doesn't show the roughly linear correlation with PG contents shared by the other analytes. For these cigars, the effective influence of PG is more difficult to determine due to the presence of complex flavoring blends.In the experimental cigars, the increase in CO, NFDPM and water is clearly related to a higher PG content. PG determines such increase triggering of some still unclarified mechanisms. Among them a variation in combustion conditions perhaps plays an important role.The increase in water content is also related to its higher percent per gram of cigar tobacco, due to the PG effects in both replacing tobacco and attracting and binding moisture. Thermal degradation of PG could also contribute to the increase in CO, while the increase in NFDPM is partly due to pure PG amount delivered from tobacco to smoke.The decrease in nicotine content seems totally related to reduced quantity of tobacco, due to the higher presence of PG.