Smoke Toxicity Research Articles

Sub-Acute Toxicity Assay of the smoke of Seeds of Azadirachta indica and Peels of Citrus sinensis used as natural insecticides on the Liver, Kidney, Lungs and Heart of Albino Rats

Abstract Natural plant parts such as seeds of Azadirachta indica (neem seeds) and peels of Citrus sinensis (sweet orange) have been used as house-hold remedies against various ailments and bio-pesticides for agricultural purpose due to their repellent, growth regulatory and anti-feedant properties against insects. Despite their beneficial role, these natural insecticides could also have toxic effects on some vital organs of human. Therefore, this study aimed to investigate the sub-acute toxicity of smoke of the Seeds of Azadirachta indica and Peels of Citrus sinensis on the liver, kidney, lungs and heart of swiss albino rats. In this study, three groups of white swiss albino rats were exposed to the smoke of A indica seeds, peels of C sinensis and their combination at different duration of one hour and two hours respectively. The Control group were not exposed to any of the natural insecticides and were fed normal diet and water. After four weeks of the treatment, the animals were all sacrificed and their liver, kidneys, lung and heart were evaluated using standard biochemical and histopathological techniques. The levels of serum biochemical indices for liver (aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total bilirubin and protein), kidneys (urea, creatinine and electrolytes), and heart (creatine kinase and lactate dehydrogenase) were found to be significantly higher at (p<0.05) for all the groups treated with the two natural insecticides when compared to control group. Histopathological changes including fibrosis, hemorrhages, vascular congestion and necrosis were observed in the liver, kidneys and lungs tissues of the rats exposed to the smoke of the seeds of A indica. However, no histopathological changes were observed in all organs of rats exposed to the smoke of the peels of C sinensis compared to control group. Moreover, the severity of the effects of smoke of these natural insecticides on both biochemical and histopathological indices increases with increase in duration of exposure. The results of this study revealed that seeds of A indica have significant toxic effects on both the tissue and biochemical markers of all the major organs of the Swiss albino rats, while peels of C sinensis shows effect on only the biochemical indices at the specific duration of time studied.

Waterpipe size matters: the effect of waterpipe size on toxicant exposures and subjective experiences.

Waterpipe (WP) tobacco smoking remains popular among US young adults, yet specific regulations for WP devices are lacking. This study examines how WP device size (base volume and height) affects smoking behavior, toxicant exposures, and subjective experiences. Thirty-eight individuals who smoke WP aged 21 to 39 participated in a randomized crossover study. Each completed three 45-minute ad libitum smoking sessions using small, medium, and large WP sizes. Saliva nicotine and exhaled carbon monoxide (eCO) were measured before and after smoking. Puff topography was recorded during sessions, and subjective smoking experiences were collected afterward. Significant differences were observed in saliva nicotine between the three WP sizes, with higher concentrations for the small WP relative to larger sizes (Ps<0.05). Exhaled CO was significantly higher after smoking the large WP compared to smaller sizes (Ps<0.05). Puff topography revealed significant differences and followed a dose-response pattern, with larger size associated with longer puff duration, greater smoke volume inhaled, and larger puff volume (Ps<0.05). The large WP was associated with enhanced subjective experiences for satisfaction and concentration compared to the small WP (Ps<0.05). WP size substantially impacts smoking experiences and exposures. Regulation of WP size should be essential in comprehensive tobacco control policies aimed at curbing WP use among young adults. These findings will aid in developing of WP size-specific standards to regulate the marketing and sales of WP devices. Such regulations should aim to minimize toxicant exposure by controlling the dimensions and design of WP components, which can significantly influence smoking behavior and toxicant intake. This study underscores the critical role of waterpipe (WP) size in shaping smoking behavior, experiences, and exposures among young adults.

Characteristics and toxicity of burning smoke released from non-metallic materials of ships in a closed environment

Characteristics and toxicity of burning smoke released from non-metallic materials of ships in a closed environment

Effect of tetrapeptides KK1 and KK5 on the immunological parameters of rat spleen during passive smoking

One of the trends in experimental and clinical immunology is the creation of new immunomodulators aimed at correcting various variants of the pathology of the immune system. Of interest are non-toxic, hormone-free and protease-resistant tetrapeptides, homologue of the of adrenocorticotropic hormone fragment (15- 18). There is little data in the literature on the effect of the above immunomodulators on the immunological parameters of the rat spleen on xenobiotic exposure models, which makes research relevant in this aspect. For the first time, the effect of tetrapeptides with laboratory ciphers KK1 and KK5 on the immunological parameters of the spleen of 36 female Wistar rats with passive smoking was evaluated. The experimental rats were fumigated with tobacco smoke for 8 hours daily for 20 days. Synthetic tetrapeptides were administered intranasally at a dose of 40 micrograms per kg/day, starting from the 10th day of the experiment. It was found that the studied tetrapeptides had a unidirectional positive effect on the immunological parameters of the spleen of experimental animals with passive tobacco smoking. This was expressed in a tendency to restore the pool of cells with CD3, CD4, CD8, CD20 markers to the level of the control group, as well as spontaneous and induced cytokine production by splenocytes. The shifts in the parameters of the spleen identified in this work may be based on a number of possible causes. Firstly, passive smoke causes a stress response in rats, which is confirmed by previous studies on a similar model, on an increase in the level of stress hormones in the blood serum of Wistar rats. Secondly, the literature data indicate the activation of lipid peroxidation during smoking. Thirdly, it is known that under the action of tobacco smoke toxicants, the lymphoid cell line suffers the most, since their polyhydrooxidized metabolites accumulate in the bone marrow and lymphoid organs, causing hypoplasia of the central and peripheral organs of immunity. A visible sign of this phenomenon is a decrease in the cellularity in the spleen, which is established in this work. Considering that active and passive smoking causes hypoxia and increases lipid peroxidation, the use of tetrapeptides KK1 and KK5 as agents that improve the body’s adaptation to hypoxia and increase resistance to stress damage is justified. Thus, the tetrapeptides KK1 and KK5 have a positive immunomodulatory effect, reducing the toxic stress effects of passive smoking.

Thermal Research on Toxicity of Smoke from Mine Cable Fires

Thermal Research on Toxicity of Smoke from Mine Cable Fires

Flame retardant polyurethane foam prepared from compatible blends of ammonium ligninsulfonate-based and zinc alginate

Abstract Zinc alginate (ZnAlg) was prepared and subsequently employed to modify ammonium ligninsulfonate-based polyurethane foams (PUFs). A range of analytical techniques, including thermogravimetry, integral programmed decomposition temperature, activation energy, smoke density, cone calorimetry and scanning electron microscopy, were employed to characterise the modified PUFs. The results demonstrated that the PUFA15Z5 (15 % ammonium lignin sulfonate and 5 g ZnAlg) with the lowest mass loss exhibited the second-highest sample decomposition temperature (T50 %), second-highest peak temperature (TMAX2), IPDT and activation energy. Furthermore, the PUFA15Z5 sample exhibited the smallest smoke density (23.11) and the highest light transmittance (67.11 %). The peak heat release rate, total heat release, smoke production rate, total smoke release and four fire risk assessment indicators of the PUFA15Z5 were the lowest, while its carbon residue was the densest. The results demonstrated that the PUFA15Z5 exhibited the most favourable thermal stability, flame retardant properties and the lowest smoke toxicity. These findings provided a valuable reference for subsequent biomass-based flame retardant modified polyurethane foams (PUFs).

Effect of ammonium polyphosphate on flame retardancy of bio-based rigid polyurethane foams

Rigid polyurethane foam (RPUF) has attracted a lot of attention as a multifunctional material. However, the use of fossil fuels in various fields is limited due to their flammability and excessive consumption in the preparation process. In order to solve this problem, a sustainable bio-based RPUF was prepared by ammonium polyphosphate (APP) and lignin-based polyol flame-retardant modification. The impact of APP on the smoke characteristics, flame retardancy, and thermal behavior of lignin-based polyol RPUFs was examined. The modified RPUF (RPUF-20) with 20 wt.% APP had the greatest starting temperature and residual rate. The maximum activation energy (E) and best thermal stability were found in the pyrolysis kinetics calculation utilizing the thermogravimetric trajectory compared with other specimens. Cone showed that when RPUF-20 was compared with RPUF-0, the peak heat release rate was lowered by 79.43%, 72.79%, and 67.91%, and the total heat release was reduced by 50.59%, 56.29%, and 37.14%, respectively. In addition, RPUF-20 had the lowest smoke density, according to the statistics. The current results showed that RPUF-20 had low smoke toxicity and outstanding flame retardancy, which gave rise to a novel notion for RPUFs following flame-retardant modification using biomass.

In Situ and Rapid Toxicity Assessment of Air Pollution by Self-Assembly Passive Colonization Hydrogel.

Air pollution is a leading environmental health risk factor, and in situ toxicity assessment is urgently needed. Bacteria-based bioassays offer cost-effective and rapid toxicity assessments. However, the application of these bioassays for air toxicity assessment has been challenging, due to the instability of bacterial survival and functionality when directly exposed to air pollutants. Here, we developed an approach employing self-assembly passive colonization hydrogel (SAPCH) for in situ air toxicity assessment. The SAPCH features a core-shell structure, enabling the quantitatively immobilization of bacteria on its shell while continuously provides nutrients from its core. An antimicrobial polyelectrolyte layer between the core and shell confines bacteria to the air-liquid interface, synchronizing bacterial survival with exposure to air pollutants. The SAPCH immobilized a battery of natural and recombinant luminescent bacteria, enabling simultaneous detection of various toxicological endpoints (cytotoxicity, genotoxicity and oxidative stress) of air pollutants within 2 h. Its sensitivity was 3-5 orders of magnitude greater than that of traditional liquid-phase toxicity testing, and successfully evaluating the toxicity of volatile organic compounds and combustion smoke. This study presents a method for in situ, rapid, and economical toxicity assessment of air pollution, making a significant contribution to future air quality monitoring and control.

A new strategy for constructing ZIF-67@PBA core-shell 3D cross-heterostructures for improving fire safety of TPU at ultra-low addition amount

Thermoplastic polyurethane (TPU) has an extensive application in many different industries. However, serious fire hazards and smoke toxicity have been the main reason limiting its wide application. Therefore, it is necessary and urgent to perform flame retardant and smoke suppression treatment for TPU. In recent years, metal-organic framework compounds (MOFs) have very promising application prospects in the fields of flame-retardant polymer composites. However, there is a problem of low flame-retardant efficiency for the original MOFs alone in polymer composites. It is reported the multi-level and multi-structured flame-retardant system has better flame-retardant efficiency than the traditional structures. So, the dual MOF core-shell heterostructure may have more effective heat reduction and smoke suppression than any single component. In this paper, a core-shell 3D cross-heterostructures nanohybrid (ZIF-67H@PBA) was prepared using ZIF-67H as the host MOF and Prussian blue nanocubes (PBA) as the guest MOF. It has been found that TPU/ZIF-67H@PBA composites with ultra-low additions have excellent fire safety. Compared with those of pure TPU, the peak heat release rate (PHRR), total smoke release (TSP), and smoke factor (SF) of the samples with 0.5wt% ZIF-67H@PBA were reduced by 33.6 %, 47 %, and 61 %, respectively. At the same time, a cone calorimeter (CCT), a homemade soot sampling device and a gas chromatography-mass spectrometry (GC–MS) coupling with each other were constructed and used to demonstrate the most realistic effects of flame retardants in terms of smoke suppression and toxicity reduction. This work provides a new strategy to design TPU flame retardants.

Fabrication of Flame-Retardant Ammonium Polyphosphate Modified Phytic Acid-Based Rigid Polyurethane Foam with Enhanced Mechanical Properties.

Ammonium polyphosphate (APP) and self-made nickel phytate (PANi) were used as modified materials to prepare green biomass rigid polyurethane foam (RPUF). The flame retardancy, thermal stability, smoke toxicity and mechanical properties of the modified RPUF were investigated by limiting oxygen index (LOI), a cone calorimetry (CONE) test, thermogravimetric analysis and a compression test. The results showed that the RPUF with 10 wt% APP (PANi/APP10) had the highest LOI of 26.5%. Its peak heat release rate (PHRR) and total heat release (THR) were reduced by 29.64% and 24.05% compared with PANi/APP0 without APP. And its smoke production rate (SPR) and total smoke release (TSR) decreased by 33.14% and 19.88%, respectively. Compared with pure RPUF, the compressive strength of PANi/APP10 was increased by 50%, mainly because APP itself was an ultra-fine powder, which was better compatible with the matrix and improved the hardness of the material. The results showed that the synergistic effect of the gas phase and the condensed phase mechanism could effectively improve the flame-retardant effect. The current research results provided a new strategy for the preparation of green and low-toxicity RPUF.

Carbon nitride/polyaniline/metal oxide composite system endows epoxy resin with reinforcements in the fire safety, thermal stability, and water resistance

AbstractReducing the fire risk of epoxy coatings has been a significant focus in the research of thermosetting resin materials. Various carbon nitride/polyaniline/metal oxide hybrids (CNPMOs) were synthesized using in‐situ oxidative polymerization and modified adsorption methods. Combustion analysis results indicated that CNPMOs effectively reduced the heat release of epoxy coatings during combustion. The epoxy coatings containing various CNPMOs (EFe, EY, and ETi) exhibited excellent smoke suppression and toxicity reduction properties. Furthermore, in comparison to the pure sample (E0) and reference sample (E1), the epoxy coatings EFe, EY, and ETi demonstrated improved thermal stability. In water resistance tests, the water absorption rates of EFe, EY, and ETi were significantly lower than that of E0. The CNPMOs enhanced the hydrophobicity of the epoxy coating to better protect the substrate in humid environments.

Toxicity of waterpipe tobacco smoking: the role of flavors, sweeteners, humectants, and charcoal.

Waterpipe tobacco (WPT) smoking is a public health concern, particularly among youth and young adults. The global spread of WPT use has surged because the introduction of pre-packaged flavored and sweetened WPT, which is widely marketed as a safer tobacco alternative. Besides flavorants and sugars, WPT additives include humectants, which enhance the moisture and sweetness of WPT, act as solvents for flavors, and impart smoothness to the smoke, thus increasing appeal to users. In the United States, unlike cigarette tobacco flavoring (with the exception of menthol), there is no FDA product standard or policy in place prohibiting sales of flavored WPT. Research has shown that the numerous fruit, candy, and alcohol flavors added to WPT entice individuals to experience those flavors, putting them at an increased risk of exposure to WPT smoke-related toxicants. Additionally, burning charcoal briquettes-used as a heating source for WPT-contributes to the harmful health effects of WPT smoking. This review presents existing evidence on the potential toxicity resulting from humectants, sugars, and flavorants in WPT, and from the charcoal used to heat WPT. The review discusses relevant studies of inhalation toxicity in animal models and of biomarkers of exposure in humans. Current evidence suggests that more data are needed on toxicant emissions in WPT smoke to inform effective tobacco regulation to mitigate the adverse impact of WPT use on human health.

A Cu‐MOF‐decorated ammonium polyphosphate for epoxy resins with reduced smoke release and enhanced char layer

AbstractInspired by the significant catalytic charring effect of metal–organic frameworks (MOFs), Cu‐MOF decorated ammonium polyphosphate (APP@Cu‐MOF) was prepared by coupling agents to improve the fire safety of epoxy resin (EP). After adding 9 wt% APP@Cu‐MOF, the fire performance of EP is significantly improved with limiting oxide index (LOI) value of 29.4 and UL‐94 V‐0 rating. The peak heat release rate (PHRR), total smoke production (TSP), CO production, and CO2 production of EP composite samples decreased by 34.6%, 54.7%, 24.6% and 30.0%, respectively. It is proposed that the synergistic effect among Cu‐MOF and APP promoted the char formation of EP. The dense carbon layers formed a barrier that prevented the transfer of heat and inhibited the release of toxic gases, thus acting as a flame retardant. This work provides a new strategy to develop a high‐efficient MOF‐decorated flame retardant with smoke inhibition, toxicity reduction, and catalytic carbonization effect.

Enhancing the thermal and mechanical properties of sulfonated peek fiber composites with reduced smoke density and toxicity

AbstractPolyether ether ketone (PEEK) sulfonation process is a reasonably easy but time‐consuming to manufacture composites. This study focuses on altering PEEK powder in a sulfuric acid solution via a sulfonation process to develop sulfonated PEEK (SPEEK) resin for the fiber‐reinforced thermoplastic composite manufacturing and characterization steps. In this study, about 5 wt% PEEK powder was sulfonated in 98% sulfuric acid solution for 12 h at 65°C. The water bath technique was used for the precipitation process to obtain the SPEEK polymer. After proper washing and drying, the SPEEK matrix (resin) was obtained by dissolving it in dimethylformamide in a ratio of 1:2. This resin solution was then used to manufacture thermoplastic Kevlar and glass fiber‐reinforced composites employing wet layup process and cured at an elevated temperature under pressure. These SPEEK composites passed the flame retardancy UL94 test with a V0 rating. The average water contact angle of the glass fiber‐ and Kevlar‐SPEEK composites is 93.67° and 102.24°, respectively. The average tensile strength values of these composites were found 222.22 and 284.35 MPa, correspondingly. The smoke density and toxicity tests of the glass fiber‐SPEEK composite confirmed lower smoke generation with the modifications. These SPEEK‐fiber composites can be considered for various industrial applications, including aviation, energy, drone, defense, and automotive.

Acute Dermal Toxicity of Liquid Smoke (Cocos nucifera L.) Grade 1

Liquid smoke, a product from coconut shell waste, is a food preservative and antimicrobial substitute. It is produced through pyrolysis at 400-600°C, producing solid, liquid, and gas products. Toxicity studies need to be conducted to test the safety of medicinal products. This is because medicinal products that meet the requirements are those that have proven their efficacy and safety. Liquid smoke, especially grade 1, has not been studied further regarding its safety. This study aimed to determine the acute toxicity potential of grade 1 coconut shell liquid smoke. The experimental method involved collecting and processing samples, making liquid smoke, purifying them, and testing the effects of acute dermal toxicity. Results showed mild damage to liver and kidney organs, with microscopic liver tissue damage and kidney tissue damage. Keywords: Cocos nucifera L., liquid smoke, toxicity, acute, subchronic

Mortality attributable to PM 2.5 from wildland fires in California from 2008 to 2018

In California, wildfire risk and severity have grown substantially in the last several decades. Research has characterized extensive adverse health impacts from exposure to wildfire-attributable fine particulate matter (PM 2.5 ), but few studies have quantified long-term outcomes, and none have used a wildfire-specific chronic dose-response mortality coefficient. Here, we quantified the mortality burden for PM 2.5 exposure from California fires from 2008 to 2018 using Community Multiscale Air Quality modeling system wildland fire PM 2.5 estimates. We used a concentration-response function for PM 2.5 , applying ZIP code–level mortality data and an estimated wildfire-specific dose-response coefficient accounting for the likely toxicity of wildfire smoke. We estimate a total of 52,480 to 55,710 premature deaths are attributable to wildland fire PM 2.5 over the 11-year period with respect to two exposure scenarios, equating to an economic impact of $432 to $456 billion. These findings extend evidence on climate-related health impacts, suggesting that wildfires account for a greater mortality and economic burden than indicated by earlier studies.

Tri-phase flame retardant system towards advanced energy-saving building materials with highly efficient fire and smoke toxicity reductions

The extensive usage of rigid polyurethane foam (RPUF) as an energy-saving building materials in construction has raised concerns about fire risks and toxic hazards. To address these challenges, a melamine-derived polyol (MADP) was synthesized using the Mannich reaction, resulting in inherently flame-retardant RPUF materials with the introduction of flame-retardant functional groups. Furthermore, a novel MoS2-Cu2O nanohybrid was prepared and employed to enhance flame retardancy and suppress smoke toxicity in RPUF through a cooperative effect with expandable graphite (EG). The resulting M-RPUF/EG/MoS2-Cu2O nanocomposite exhibited remarkable fire safety, as evidenced by significant reductions in peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and peak carbon monoxide (CO) release, amounting to 76.9 %, 64 %, 82 %, and 99 % respectively, compared to pristine RPUF. Furthermore, the nanocomposite effectively addressed interfacial defects and significantly enhanced the mechanical property and thermal stability. The significant improvement in fire safety is mainly ascribed to the catalytic charring effect of MADP and EG, as well as the catalytic oxidation of MoS2-Cu2O nanohybrids, resulting in the formation of a thermally stable protective layer in the condensed phase. Based on these results, the integration of the tri-phase flame retardant system holds great potential for advancing the development of fire-safe polyurethane materials.

Reliability study of fire suppression using dodecafluoro-2-methylpentan-3-one in small-sized confined space: From a temperature and gaseous products viewpoint

Despite the vast progress in fire-extinguishing agents and technology, the early-stage fire suppression in small-sized confined space (SCS) remains a challenge. This study introduces the reliability of SCS flame inhibition using dodecafluoro-2-methylpentan-3-one (C6F12O) through a self-assessment experimental platform to investigate the effectiveness, thermal effects, and toxic characteristics of gaseous products of C6F12O in extinguishing SCS fires. The results show that the fire extinguishing and cooling effects of C6F12O, as well as the smoke toxicity of its products, can be influenced by the agent dosage, SCS fire source setup, and spatial structure. The fire extinguishing and cooling effects of C6F12O are superior to those of H2O, and these effects can be enhanced with the increase in flow rates that are applied. However, after the extinguishing of the fire, a large quantity of toxic and irritating gaseous products will be produced, and such a risk can be reduced with excessive application of C6F12O. For SCSs with a simple structure (unobstructed condition), fires breaking out in their middle sections will pose a greater fire thermal hazard, and gas products after the application of C6F12O for fire extinguishing will present greater smoke toxicity. The thermal hazards of fires in the middle sections of SCSs can be significantly reduced with the addition of obstruction conditions inside the SCSs. However, there is an insignificant effect on the smoke toxicity of products after the extinguishing of fire. These research conclusions offer a breakthrough in the development of new fire-extinguishing materials (devices) primarily based on C6F12O for active prevention and control of initial SCS fires.

Improving the quality and toxicity of rice husk liquid smoke to control edamame soybean pests

Purpose of the research to improve the quality and toxicity of husk charcoal liquid smoke which is effective and selective in controlling edamame soybean plant pests, safe for predatory and pollinators arthropods, and does not contain the dangerous compound Benzo(a)pyrene. The resulting product can be used as a substitute for synthetic insecticides which are non-selective and unsafe for predators, pollinators and human health. The technique used was to set the temperature of the pyrolysis process between 200-300°C to produce grade 3 and distillation of grade 3 to grade 2 with a temperature of 80-100°C. Research was carried out at Jember State Polytechnic, from August to September 2023. The observation parameters were content of grade 3 and grade 2 compounds using GCMS, Bioassay tests against S. litura 3rd instar using concentrations of 0%, 1%. 2%, 3%, 4% and 5% each for 10 test insects, with 3 repetitions, using the feed immersion method. LC50 and LC95 test used PoloPlus 1.0. Field tests compared arthropod diversity, grade 3, grade 2 and Imidacloprid treatments, using the Kruskal-Wallis test. The diversity index uses the Shannon-Wiener (H’) and Sympson Dominance Index (C’) formulas. Conclusion LC95 grade 3 was 3%, Grade 2 was 4%. Both were not found Benzo(a)pyrene. The grade 3 pest population was not significantly different compared to Imidacloprid. Grade 3 and grade 2 predators and pollinators were higher than Imidacloprid, the diversity of Grade 3, grade 2 and Imidacloprid treatments were moderate diversity, balanced ecosystem and no species dominance found.

Bio-based P–N flame retardant with ZIF-67 in-situ growth on flexible polyurethane foam with excellent fire safety performance

The wide application of flexible polyurethane foam (FPUF) poses a giant challenge to human society in terms of fire prevention and environmental pollution. To solve this problem, the lignocellulose-based P–N flame retardant (LFPN) has been developed using mechanochemical methods. It was found that FPUF treated using LFPN exhibited good flame retardancy, but suffered from high smoke generation and toxicity. The hollow dodecahedral ZIF-67 has been used for smoke suppression catalysis, but the agglomeration phenomenon makes it inefficient. Hence, in this study, the adhesive properties of polydopamine (PDA) were utilized to assist the in-situ growth of ZIF-67. The results showed that the total smoke release rate of the treated FPUF was reduced by 40.5%. The toxic gases, such as carbon monoxide (CO), hydrogen cyanide, etc., also showed the same decreasing trend. What's more, the catalytic effect of ZIF-67 itself and the synergistic effect with LFPN gave FPUF great flame retardant and smoke inhibition properties. This novel FPUF provides a new reference for achieving smoke suppression and toxicity reduction.