Composition Of Smoke Research Articles

How environmentally friendly is the disposal of clear aligners? A gas chromatography-mass spectrometry study

Used clear aligner trays are often indiscriminately disposed of with general plastic waste and incinerated. This study aimed to analyze the smoke composition from incinerating 2 common aligner materials: glycol-modified polyethylene terephthalate (PET-G) and polyurethane. Each of the 2 materials in triplets was thermoformed. The thermoformed trays were shredded and subjected individually to open-fire combustion, ignited using a methane torch, in a specially designed combustion chamber. The resultant smoke was collected and analyzed using gas chromatography-mass spectrometry to study its in-depth composition. A total of 20 peaks, corresponding to 20 compounds, were identified from each of the 2 material samples. O-xylene (21.06%) showed the maximum concentration in the PET-G sample, whereas 1,4-dimethyl-1,3-cyclohexadiene in polyurethane (18.88%). The first peak in the PET-G sample corresponded to benzene with a relative concentration of 5.18%. Four compounds were common to both samples: 1,4-dimethyl-1,3-cyclohexadiene; 1,3-cyclohexadiene, 2,3-dimethyl-; 1-hydroxymethly-4-methylenecyclohexane; and cyclohexanemethanol, 4-methylene-. Benzene, a group 1 carcinogen, was identified in the PET-G smoke sample, whereas tetrahydrofuran, a suspected carcinogen, was found in the polyurethane sample. Some compounds were hazardous, whereas most were skin, eye, and respiratory irritants. Possible mitigation strategies include proper case selection, efficient manufacturing, direct 3-dimensional printing, and developing biodegradable materials. Clinicians can set up 'used aligner collection points' to ensure responsible disposal. Proper disposal guidelines and stringent regulations are the need of the hour.

Using computer vision to classify, locate and segment fire behavior in UAS-captured images

The widely adaptable capabilities of artificial intelligence, in particular deep learning and computer vision have led to significant research output regarding flame and smoke detection. The composition of flame and smoke, also described as fire behavior, can be considerably different depending on factors like weather, fuels, and the specific landscape fire is being observed on. The ability to detect definable classes of fire behavior using computer vision has not been explored and could be helpful given it often dictates how firefighters respond to fire situations. To test whether types of fire behavior could be reliably classified, we collected and labeled a unique unmanned aerial system (UAS) image dataset of fire behavior classifications to be trained and validated using You Only Look Once (YOLO) detection models. Our 960 labeled images were sourced from over 21 h of UAS video collected during prescribed fire operations covering a large region of Texas and Louisiana, United States. National Wildfire Coordinating Group (NWCG) fire behavior observations and descriptions served as a reference for determining fire behavior classes during labeling. YOLOv8 models were trained on NWCG Rank 1–3 fire behavior descriptions in grassland, shrubland, forested, and combined fire regimes within our study area. Models were first trained and validated on classifying isolated image objects of fire behavior, and then separately trained to locate and segment fire behavior classifications in UAS images. Models trained to classify isolated image objects of fire behavior consistently performed at a mAP of 0.808 or higher, with combined fire regimes producing the best results (mAP = 0.897). Most segmentation models performed relatively poorly, except for the forest regime model at a box (locate) and mask (segment) mAP of 0.59 and 0.611, respectively. Our results indicate that classifying fire behavior with computer vision is possible in different fire regimes and fuel models, whereas locating and segmenting fire behavior types around background information is relatively difficult. However, it may be a manageable task with enough data, and when models are developed for a specific fire regime. With an increasing number of destructive wildfires and new challenges confronting fire managers, identifying how new technologies can quickly assess wildfire situations can assist wildfire responder awareness. Our conclusion is that levels of abstraction deeper than just detection of smoke or flame are possible using computer vision and could make even more detailed aerial fire monitoring possible using a UAS.

On-Line Analysis of Cigarette Smoke Based on Microwave Plasma Torch Mass Spectrometry.

Cigarette smoke contains a large number of chemicals, including both flavor components and harmful substances. The mainstream smoke (MSS) generated by smoking is directly inhaled by individuals, making it crucial to establish an effective method for smoke detection and analysis. One promising technique for analyzing smoke is MPT-MS (Microwave plasma torch mass spectrometry). This approach offers several advantages in accurately detecting the composition of cigarette smoke. By combining MPT-MS with a smoke pumping device, we can achieve real-time online detection of smoke components. We successfully detected 22 flavor compounds present in the smoke. These compounds contribute to the distinct taste of cigarettes. Moreover, we identified 2 polycyclic aromatic hydrocarbons (PAHs) in the smoke. PAHs are known carcinogens and are of great concern in terms of their potential health risks. The successful detection and identification of flavor compounds and PAHs using our method confirm the online detection capability of MPT-MS. This approach provides an efficient and reliable means for analyzing the complex composition of cigarette smoke. By utilizing MPT-MS, we can gain valuable insights into the chemical composition of cigarette smoke and can inform the development of strategies and policies aimed at reducing the harmful effects of smoking and protecting public health.

Clearing the Smoke: The Evidence behind Risk of Electrocautery Smoke and Mitigation Strategies.

Electrocautery has been a useful, fundamental instrument utilized for surgical procedures since its implementation in the 1920s. However, concerns exist regarding the health hazards of the by-product smoke associated with the use of electrocautery. A comprehensive review of articles on the composition, mitigation, and effects of smoke was conducted using the PubMed search engine and excluding articles that did not meet the predetermined inclusion criteria. From January 1963 to December 2021, a total of 264 articles resulted, and a total of 69 articles were included in this narrative review. Surgical smoke contains volatile organic compounds, polycyclic aromatic compounds, viral particles, and ultrafine particles. There has been some evidence of mutagenicity to bacterial cells during animal in vivo studies, and one human survey study has shown similar mutagenic effects. We also discuss additional hemostatic techniques that can be used, including the use of hemostatic and antithrombolytic agents, epinephrine infiltration, and the use of tourniquet when appropriate. Further studies should be conducted regarding human effects, but until the data are available, we recommend precautionary measures and actions to protect operating room staff from cautery smoke exposure.

Chemical composition and antibacterial activity of coconut-shell liquid smoke to maintain the texture of fresh meat

This research focused on the evaluation of raw broiler chicken meat texture and pathogenic antibacterial effect under the treatment of grade 2 coconut-shell liquid smoke (CSLS) as a food preservative. Compound identification of grade 2 CSLS was conducted using the GC-MS method. The main chemical compounds of CSLS were polyunsaturated fatty acid derivates, fatty acid and phenol. The evaluation of texture was conducted on raw broiler chicken meat under the treatment of grade 2 CSLS during storage at 25 ℃ for 7 days. The effect of antibacterial activity of grade 2 CSLS with different concentration (i.e., 5%, 25%, 50%, and 75%) were tested using Gram-positive bacteria on several pathogenic bacteria such as L. monocytogenes, S. aureus, P. Aeruginosa, and E. coli. The results indicated that grade 2 CSLS influenced the inhibited zone of L. monocytogenes, S. aureus, P. Aeruginosa, and E. coli respectively with linear correlation. The optimal concentration of grade 2 CSLS resulted in a concentration of 50%, which was the most optimal against L. monocytogenes, S. aureus, P. Aeruginosa, and E. coli as pathogenic bacteria strains.

Comparative Analysis of Particulate Content in Cigarette Smoke: Implications for Respiratory Health of Active and Passive Smokers

Cigarette smoke is a heterogeneous mixture of gases, uncondensed vapours and liquid particulate matter with millions of particles per cubic centimetre. Cigarette smoking can negatively impact the health of smokers and non-smokers. As such, there is a need to constantly assess the quantity of toxic substances emanating from smoking cigarettes. This study investigated the total amount of particulates to which smokers and non-smokers are exposed and identified the chemical compositions of total particulates in cigarette smoke from some selected cigarette brands obtained from Nagongera town council shops in Uganda. To achieve this, we made use of an apparatus that mimics the smoking process of a human being and a passive smoker by connecting this set to another set-up containing a cigarette to be burnt. Qualitative tests for chemical composition were conducted using conventional tests for organic functional groups. It was found that Sportsman and locally cured tobacco had the highest total particulate content (116 mg and 73 mg) while Supermatch and Safari had the lowest total amount of particulates 45.5 mg and 40.3 mg, respectively. The investigated cigarettes were found to be composed of the following functional groups: aromatics, phenolics, nitrosamines and alkaloids. However, aldehyde and ketonic groups were not identified. The cigarette composition results in cigarette smoke composition either in the mainstream or the side stream causing disease to a respiratory system like lung cancer, emphysema and cancers in the mouth cavity and oesophagus. This study confirmed that the brand of cigarette smoked could determine the quantity of particulate smokers and non-smokers of cigarettes might be exposed to and that functionalities and/or chemical compositions vary amongst Ugandan cigarette brands

The Impact of Electrocautery Smoke on Surgical Staff and the Efficacy of Normal Surgical Masks Versus N95 Masks.

Electrocautery is a commonly used technique in surgical procedures, generating smoke that poses health risks to surgical staff. This study investigates the comparative efficacy of normal surgical masks versus N95 masks in mitigating the harmful effects of electrocautery smoke. Through a systematic review of literature spanning two decades, we explore the causes and effects of electrocautery smoke exposure, including potential long-term inhalation effects. Our findings highlight significant disparities in the protection offered by different masks and underscore the importance of adequate respiratory protection in surgical settings. In addition, we examine the factors influencing the generation and composition of electrocautery smoke, such as the power settings used, the type of tissue being cauterized, and the duration of the procedure. Furthermore, we discuss the potential health risks associated with long-term exposure to electrocautery smoke, including the possibility of respiratory conditions, cardiovascular effects, and carcinogenicity. Our analysis also addresses the importance of implementing appropriate smoke evacuation systems and optimizing operating room ventilation to minimize the concentration of smoke particles in the surgical environment. Overall, this comprehensive analysis provides valuable insights into the impact of electrocautery smoke in surgical settings and the varying levels of protection offered by different masks.

The Puzzle of Marijuana Use and Forced Vital Capacity.

In study after study, marijuana use has been found to be associated with increased forced vital capacity (FVC). This is puzzling, because marijuana is commonly consumed by inhalation of its smoke, and smoke exposure of any kind is not generally considered a cause of increased FVC. Although this observation was first made decades ago, a satisfactory explanation remains elusive. In this review we survey the evidence supporting the relationship between marijuana use and increased FVC, discuss potential threats to validity when inferring causation, and, presupposing a possible causal relationship, pose two key questions. First, what are possible physiologic or pathophysiologic mechanisms by which marijuana use might increase FVC? Second, why might this effect be consistently observed with marijuana use but not with tobacco use? Explanations for the first question include lung and chest growth and remodeling from strenuous marijuana smoke inhalation and reductions in lung elastic recoil from marijuana smoke exposure. Explanations for the second include differences between marijuana and tobacco in smoke composition and patterns of consumption, such as smoking topography. Finally, the possibility that smoke, whether from marijuana or tobacco, might have nonmonotonic effects on FVC depending on the degree of exposure is explored. In synthesizing a curated breadth of epidemiologic and physiologic science, we leverage a perplexing observation to generate potential insights and avenues for further research into the biological effects of smoke, from marijuana or otherwise, on the respiratory system.

Role of Environmental Factors in Transmission of Novel Corona Virus (Covid 19) and the Effect and Composition of Smoke

Role of Environmental Factors in Transmission of Novel Corona Virus (Covid 19) and the Effect and Composition of Smoke

Biomass-burning smoke's properties and its interactions with marine stratocumulus clouds in WRF-CAM5 and southeastern Atlantic field campaigns

Abstract. A large part of the uncertainty in climate projections comes from uncertain aerosol properties and aerosol–cloud interactions as well as the difficulty in remotely sensing them. The southeastern Atlantic functions as a natural laboratory to study biomass-burning smoke and to constrain this uncertainty. We address these gaps by comparing the Weather Research and Forecasting with Chemistry Community Atmosphere Model (WRF-CAM5) to the multi-campaign observations ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS), CLARIFY (CLoud–Aerosol–Radiation Interaction and Forcing), and LASIC (Layered Atlantic Smoke Interactions with Clouds) in the southeastern Atlantic in August 2017 to evaluate a large range of the model's aerosol chemical properties, size distributions, processes, and transport, as well as aerosol–cloud interactions. Overall, while WRF-CAM5 is able to represent smoke properties and transport, some key discrepancies highlight the need for further analysis. Observations of smoke composition show an overall decrease in aerosol mean diameter as smoke ages over 4–12 d, while the model lacks this trend. A decrease in the mass ratio of organic aerosol (OA) to black carbon (BC), OA:BC, and the OA mass to carbon monoxide (CO) mixing ratio, OA:CO, suggests that the model is missing processes that selectively remove OA from the particle phase, such as photolysis and heterogeneous aerosol chemistry. A large (factor of ∼2.5) enhancement in sulfate from the free troposphere (FT) to the boundary layer (BL) in observations is not present in the model, pointing to the importance of properly representing secondary sulfate aerosol formation from marine dimethyl sulfide and gaseous SO2 smoke emissions. The model shows a persistent overprediction of aerosols in the marine boundary layer (MBL), especially for clean conditions, which multiple pieces of evidence link to weaker aerosol removal in the modeled MBL than reality. This evidence includes several model features, such as not representing observed shifts towards smaller aerosol diameters, inaccurate concentration ratios of carbon monoxide and black carbon, underprediction of heavy rain events, and little evidence of persistent biases in modeled entrainment. The average below-cloud aerosol activation fraction (NCLD/NAER) remains relatively constant in WRF-CAM5 between field campaigns (∼0.65), while it decreases substantially in observations from ORACLES (∼0.78) to CLARIFY (∼0.5), which could be due to the model misrepresentation of clean aerosol conditions. WRF-CAM5 also overshoots an observed upper limit on liquid cloud droplet concentration around NCLD= 400–500 cm−3 and overpredicts the spread in NCLD. This could be related to the model often drastically overestimating the strength of boundary layer vertical turbulence by up to a factor of 10. We expect these results to motivate similar evaluations of other modeling systems and promote model development to reduce critical uncertainties in climate simulations.

PSIV-26 Development of a Controlled Exposure Particulate and Oxidative Radical Mask for Causality Experiments Investigating Smoke Exposure on Livestock Animals

Abstract Understanding and mapping the specific effects of smoke inhalation on cattle performance provides strategic insights for producers and policy makers to better prepare or adjust when faced with sporadic or even seasonal reductions in air quality. As of now, no current studies have attempted to investigate the effects of seasonal fires on performance and health adequately in livestock while addressing obvious confounding effects, controlling exposure, and examining fuel for differential oxidative radicals and particulate smoke. Herein, we propose the design of the first cost-effective controlled system for investigating smoke, particulate matter, and varied oxidative radicals through a pre-mixing chamber. The mask main body is constructed from 8” nominal diameter schedule 40 PVC pipe. The endcap was designed in an online CAD software to provide an interface for standard 2 ⅞” bulkhead fittings and was produced via additive manufacturing (3D printing). A silicone SCUBA neck seal was used to line the face orifice and is the component that directly contacts the animal’s nose and mouth. A neoprene rubber sheet and an insulation hose were used as padding under the silicone seal to help maintain an airtight connection and animal comfort when the mask is worn. Bulkhead fittings used provide 1 ½” female national pipe thread connection to allow for modular connection of inlet and outlet hoses, check valves for airflow isolation, filters, or any number of connections can be made via these gasket sealed fittings, making this platform extremely adaptable. In its shown configuration, 3D printed adapters were made to attach 4” suction hose to 2” socket union joints for quick connect/disconnect functionality. An inlet and outlet gas/smoke flow regulator are attached to a mixing chamber where particulate and chemical composition sensors are utilized to deliver the desired composition of smoke delivered to the animals. Negative pressure fans and pumps regulate the flow to the animals and are utilized for exposure of smoke in time-specific intervals. An additional fully 3D printed version enables the mask design to be lower in weight through regulation of the density of the internal matrix, and after an initial investment in the equipment also represents a cost-efficient approach to generating multiple masks. Understanding the effects of particulate and reactive oxidative molecules on livestock health and performance requires the study of a controlled exposure, the system presented herein represents a viable and cheap alternative for bettering a mechanistic model and understanding of the effects of smoke on animal health and performance. Ultimately, the proposed mask paired with currently available sensors permit for the controlled exposure of smoke particulate with different chemical compositions for accurate evaluation of prolonged exposure effects on livestock.

Effect of Capsule Burst in Cigarette Filters on the Compound Composition of Mainstream Cigarette Smoke.

The number of cigarette capsule users is increasing; however, a comprehensive epidemiological investigation comparing the harmfulness of capsule and non-capsule cigarettes, particularly concerning the composition of flavor components and mainstream smoke, is lacking. The present study aimed to investigate the effect of capsule burst on the compound composition of mainstream smoke by quantifying the Hoffmann list and flavor (geraniol, eugenol, menthofuran, and pulegone) in mainstream smoke with and without crushing the capsules. The findings indicate that while tar values tended to increase when the capsules were burst, there was no significant change observed in the other Hoffmann list components, such as nicotine, benzo[α]pyrene, tobacco-specific nitrosamines, aromatic amines, and phenolics. However, when the capsules burst, menthofuran and pulegone, which were present in the capsule and could cause toxicity, were found in the mainstream smoke via the International Standard Organization (1.5-4.0 μg/cig and 5.13-6.00 μg/cig smoking regime) and Health Canada Intense (12.8-18.2 μg/cig and 22.77-24.67 μg/cig smoking regime). Therefore, understanding the capsule composition is important, as the toxic components of the capsules can be inhaled as smoke, posing a potential health risk.

Inconsistency in the Composition of the Smoke of a Cannabis Cigarette as Smoking Progresses: Results, Mechanism, and Implications.

Background: The efficacy of cannabis treatment is determined by the active pharmaceutical ingredients (APIs) of the ingested composition. Despite smoking predominancy in cannabis treatment, very little is known regarding its yield and provision rate of cannabis APIs. Material and Methods: Ten experiments were performed, studying changes in APIs content during smoking, using a designated smoking machine. APIs content was evaluated via analysis of a cigarette's residuals and of the smoke composition; cannabinoid and terpene content were assessed. Results: Results demonstrated increased cannabinoid content in the cigarette sections closer to the mouth, as compared with those closer to the lit end. Similarly, cannabinoid content in the inhaled smoke increases as smoking progresses. Similar results are found for sesquiterpenes. Monoterpenes, having lower boiling points reach the smoke before the sesquiterpenes and cannabinoids do. Conclusion: A mechanism is proposed, including: (i) decarboxylation and evaporation of APIs adjacent to the lit end, (ii) transition of API vapors away from the hot zone, (iii) condensation of APIs in cigarette's sections closer to the mouth, and (iv) re-evaporation of APIs as the hot zone approaches, thereby reaching the smoke. Differences in the boiling points between the various APIs result in varying composition along the cigarette and in the inhaled smoke. The main implications are: (i) APIs delivery through smoking cannot be uniform, (ii) APIs amount per puff increases as smoking progresses, and (iii) terpenes are inhaled before the cannabinoids are. Thus, in addition to its known health-threatening hazards, smoking entails nonuniform provision of APIs, even within the same cigarette.

Application of Liquid Smoke from Rubber Wood Clone PB-340 as Latex Coagulant and Preservation of Natural Rubber Coagulum

The utilization of rubber wood waste in the form of liquid smoke has the potential to overcome environmental problems caused by the industry. Therefore, this study aimed to determine the potential of liquid smoke from rubberwood clone PB 340 to be used as a coagulant and preservative. Rubber wood waste was processed into liquid smoke using the pyrolysis method with a temperature of 400°C. Determination of the composition of liquid smoke was carried out using gas chromatography-mass spectrometry (GC-MS) analysis. The results showed that the rubber wood clone PB 340 contained 57.78% cellulose, 12.16% hemicellulose, and 19.01% lignin. Furthermore, volatile analysis with GC-MS showed that liquid smoke from rubber wood clone PB 340 contained 58 organic compounds. Some compounds in liquid smoke were phenols, furans, furfurals, acetic acid, and cyclopentene. The product was then tested for its performance as a latex coagulant at several concentrations of 5%, 10%, 15%, 20%, and 25% v/v, as well as storage time of 1, 7, and 14 days. The treated latex samples that had turned into coagulums were examined for their sheet quality parameters, including initial plasticity (P0), plasticity retention index (PRI), total volatile compounds, impurity, and ash content. The outcomes from all comparisons of pure liquid smoke concentrations and storage time of up to 14 days of the coagulum samples showed that in the initial plasticity value (P0), the plasticity retention index (PRI), volatile matter, ash content, and dirt content had met the applied Standard Indonesian Rubber (SIR).

Evaluation of the chemical, cytological and bacteriological compositions of surgical smoke and evaluation of purification of smoke by ultraviolet light and various filters in laparoscopic surgeries

Background: The present study aimed to assess the cytological, bacterial and chemical composition of laparoscopic surgical smoke and the evaluation of purification of surgical smoke by smoke purifying device containing ultraviolet (UV) light and various filters. Methods: Sixty patients undergoing laparoscopic abdominal surgery lasting >45 min were included in this randomized controlled study. The patients were divided into two groups: group A-smoke passing through smoke purifying device and group B-smoke without passing through smoke purifying device. Sample for cytological, bacteriological and chemical analysis were collected from both the groups. The primary outcome measures were to find the cytological, bacteriological and chemical composition of surgical smoke. The secondary outcome measure was evaluation of purification of surgical smoke by smoke purifying device containing ultraviolet light and various filters. Intergroup comparison of categorical and continuous variables was done using the Chi square test/Fisher’s exact test and unpaired t test respectively. Results: The present study shows the group A wherein smoke evacuating device containing various filters were used has no bacterial growth as well as no cells seen on cytological evaluation as compared to the group B wherein 21/30 (70.0%) cases had few lymphocytes and 3/30 (10.0%) cases had coagulase-negative Staphylococci wherein smoke evacuation device was not used. However, the chemical composition was comparable in both the groups. Conclusions: The smoke evacuation and filtration device, filtrates and clears the smoke of cells and bacteria as it passes through it.

Оценка качества коптильного дыма на основе его физико-химических характеристик

The work is devoted to the study of the physico-chemical characteristics of wood smoke used in the production of hot and cold smoked fish. The dispersion composition of wood smoke is determined depending on the temperature in the smoke formation zone and the excess air coefficient. The content of the main smoky components and polyaromatic hydrocarbons (PAHs) in the particles of the dispersed phase of wood smoke of various sizes has been established. A model of changing the dispersed compo-sition of smoky smoke in the process of hot smoking is proposed. Theoretical calculations based on the proposed models of changes in the dispersed composition have been experimentally confirmed.
 Physico-chemical and statistical research methods were used in the work.

Повышение экологической безопасности коптильного производства в соответствии с принципами устойчивого развития

The work is devoted to the study of the physico-chemical characteristics of wood smoke used in the production of hot and cold smoked fish. The dispersion composition of wood smoke is determined depending on the temperature in the smoke formation zone and the excess air coefficient. The content of the main smoky components and polyaromatic hydrocarbons (PAHs) in the particles of the dispersed phase of wood smoke of various sizes has been established. A model of changing the dispersed composition of smoky smoke in the process of hot smoking is proposed. Theoretical calculations based on the proposed models of changes in the dispersed composition have been experimentally confirmed.
 Physico-chemical and statistical research methods were used in the work.

Tobacco and Hot Pot Odor Adsorbed by Cotton, Wool, and Polyester Fabrics: Desorption Components and Dynamic Analysis

Fibrous textiles readily absorb and desorb ambient odors. However, information on the composition and dynamic analysis of tobacco smoke and hot pot odors on fabrics during desorption is limited. This study used gas chromatography–mass spectrometry to analyze the desorption components of cotton, wool, and polyester fabrics exposed to these two odors, respectively. Then, a dynamic diffusion fabric structure model demonstrated the effect of airflow velocity and fabric porosity on nicotine desorption. Furthermore, we proposed mass diffusion coefficients with different molecular weights. The results showed that cotton fabrics with tobacco smoke released many low molecular weight compounds, while with wool fabrics significantly fewer compounds were detected than for the other two fabrics. Notably, 3-ethenylpyridine, a marker of tobacco smoke, was not detected in wool fabrics. For hot pot odor, cotton fabrics released more hexanal, nonanal, and anethole than wool and polyester, while wool fabrics released many β-pinenes. The numerical results of the dynamic model showed that the air inlet velocity significantly affects the nicotine concentration in the fabric. Meanwhile, the concentration of nicotine in fabrics with lower porosity decreased faster. A lower mass diffusion coefficient will cause odors to remain in the fabric. This study aimed at the composition and the dynamics of odor in fabrics and offers essential information and simple models for reducing unnecessary washing of textiles and odor resistance textile design.

Aerosol Formation and Transfer in Open- and Closed-Ended Heated Tobacco Products

Summary A lit cigarette forms a positive and negative pressure zone by a puff with respect to the position of its paper burn line. Smoke aerosols generated from the two zones are then pulled through the rod under the puff to form the mainstream smoke. This phenomenon is fundamental to the thermophysics and the resultant chemical composition of the mainstream smoke. In this study, we created two different airflow pathways inside a heated tobacco rod by a puff, and investigated the differences in aerosol formation and its chemical compositions. The two different pressure-induced conditions, one through an open-ended tobacco rod (marked as HNB, a label of a designed airflow pathway of commercial heated tobacco products called heat-not-burn prior), and the other through a closed-ended tobacco rod (marked as NSC, a label of a novel-designed airflow pathway of heated tobacco products), were compared for their aerosol collected mass (ACM), the contents of nicotine, water and added aerosol agents such as propylene glycol (PG) and glycerol (VG), as well as selected aldehydes and ketones in the mainstream aerosol. Aerosol particle distribution and the heated temperature along different rod locations were also compared during a puff. The results indicated marked differences in the aerosol formation processes between the two HNB and NSC systems. The transfer ratios of the main aerosol components were significantly higher for the NSC; the levels of formaldehyde and acetaldehyde were significantly lower under the NSC than the HNB condition. There were also significant differences for the aerosol particle number concentration (APNC) and count median diameter (CMD) for the two systems. The lack of convective heat transfer in the aerosol formation under the NSC condition resulted in a relatively stable thermal aerosol generation zone, reflected by the temperature difference between the two systems in the selected locations. The NSC mode of tobacco heating thus offers a novel and enhanced aerosol generation for heat tobacco product designs.

Measurements from inside a Thunderstorm Driven by Wildfire: The 2019 FIREX-AQ Field Experiment

Abstract The 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field experiment obtained a diverse set of in situ and remotely sensed measurements before and during a pyrocumulonimbus (pyroCb) event over the Williams Flats fire in Washington State. This unique dataset confirms that pyroCb activity is an efficient vertical smoke transport pathway into the upper troposphere and lower stratosphere (UTLS). The magnitude of smoke plumes observed in the UTLS has increased significantly in recent years, following unprecedented wildfire and pyroCb activity observed worldwide. The FIREX-AQ pyroCb dataset is therefore extremely relevant to a broad community, providing the first measurements of fresh smoke exhaust in the upper troposphere, including from within active pyroCb cloud tops. High-resolution remote sensing reveals that three plume cores linked to localized fire fronts, burning primarily in dense forest fuels, contributed to four total pyroCb “pulses.” Rapid changes in fire geometry and spatial extent dramatically influenced the magnitude, behavior, and duration of pyroCb activity. Cloud probe measurements and weather radar identify the presence of large ice particles within the pyroCb and hydrometers below cloud base, indicating precipitation development. The resulting feedbacks suggest that vertical smoke transport efficiency was reduced slightly when compared with intense pyroCb events reaching the lower stratosphere. Physical and optical aerosol property measurements in pyroCb exhaust are compared with previous assumptions. A large suite of aerosol and gas-phase chemistry measurements sets a foundation for future studies aimed at understanding the composition of smoke plumes lifted by pyroconvection into the UTLS and their role in the climate system.