Effects of inhaled combined Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX): Toward an environmental exposure model

Agri-food waste biosorbents for volatile organic compounds removal from air and industrial gases - A review

Approximately 1.3 billion metric tons of agricultural and food waste is produced annually, highlighting the need for appropriate processing and management strategies. This paper provides an exhaustive overview of the utilization of agri-food waste as a biosorbents for the elimination of volatile organic compounds (VOCs) from gaseous streams. The review paper underscores the critical role of waste management in the context of a circular economy, wherein waste is not viewed as a final product, but rather as a valuable resource for innovative processes. This perspective is consistent with the principles of resource efficiency and sustainability. Various types of waste have been described as effective biosorbents, and methods for biosorbents preparation have been discussed, including thermal treatment, surface activation, and doping with nitrogen, phosphorus, and sulfur atoms. This review further investigates the applications of these biosorbents in adsorbing VOCs from gaseous streams and elucidates the primary mechanisms governing the adsorption process. Additionally, this study sheds light on methods of biosorbents regeneration, which is a key aspect of practical applications. The paper concludes with a critical commentary and discussion of future perspectives in this field, emphasizing the need for more research and innovation in waste management to fully realize the potential of a circular economy. This review serves as a valuable resource for researchers and practitioners interested in the potential use of agri-food waste biosorbents for VOCs removal, marking a significant first step toward considering these aspects together.

The effect of UV365/Fenton process on the removal of gaseous ethylbenzene in a bubble column reactor

As volatile organic compounds (VOCs), gaseous ethylbenzene has adverse effects on human health and ecology. Therefore, an effective degradation process is highly desirable. The Fenton process under UV 365 nm was selected as the first option to remove gaseous ethylbenzene in a bubble column reactor. The main parameters for the batch experiments were systematically studied, including H2O2 concentration, [H2O2]/[Fe2+], pH, UV wavelength, UV intensity, gaseous ethylbenzene concentration, gas flow rate, and process stability towards removal efficiency. The optimum conditions were found to be H2O2 concentration of 100 mmol·L-1, [H2O2]/[Fe2+] of 4, pH of 3.0, UV wavelength of 365 nm, UV power of 5 W, gas flow rate of 900 mL·min-1, and gaseous ethylbenzene concentration of 30 ppm, resulting in a removal efficiency of 76.3%. The study found that the Fenton process, when coupled with UV 365 nm, was highly effective in removing gaseous ethylbenzene. The degradation mechanism of gaseous ethylbenzene was proposed in the UV365/Fenton process based on EPR, radical quenching experiments, iron analysis, carbon balance, and GC-MS analysis. The results indicated that •OH played a crucial role in the process.

The explainable potential of coupling hybridized metaheuristics, XGBoost, and SHAP in revealing toluene behavior in the atmosphere

Toluene is a neurotoxic aromatic hydrocarbon and one of the major representatives of volatile organic compounds, known for its abundance, adverse health effects, and role in the formation of other atmospheric pollutants like ozone. This research introduces the enhanced version of the reptile search metaheuristics algorithm which has been utilized to tune the extreme gradient boosting hyperparameters, to investigate toluene atmospheric behavior patterns and interactions with other polluting species within defined environmental conditions. The study is based on a two-year database encompassing concentrations of inorganic gaseous contaminants every hour (NO, NO2, NOx, and O3), particulate matter fractions (PM1, PM2.5, and PM10), m,p-xylene, toluene, benzene, total non-methane hydrocarbons, and meteorological data. The experimental outcomes were validated against the results of extreme gradient boosting models optimized by seven other recent powerful metaheuristics algorithms. The best-performing model has been interpreted by employing Shapley additive explanations method. In the study, we have focused on the relationship between toluene and benzene, as its most important predictor, and provided a detailed description of environmental conditions which directed their interactions.

Development of a Smartwatch with Gas and Environmental Sensors for Air Quality Monitoring

In recent years, there has been a growing interest in developing portable and personal devices for measuring air quality and surrounding pollutants, partly due to the need for ventilation in the aftermath of COVID-19 situation. Moreover, the monitoring of hazardous chemical agents is a focus for ensuring compliance with safety standards and is an indispensable component in safeguarding human welfare. Air quality measurement is conducted by public institutions with high precision but costly equipment, which requires constant calibration and maintenance by highly qualified personnel for its proper operation. Such devices, used as reference stations, have a low spatial resolution since, due to their high cost, they are usually located in a few fixed places in the city or region to be studied. However, they also have a low temporal resolution, providing few samples per hour. To overcome these drawbacks and to provide people with personalized and up-to-date air quality information, a personal device (smartwatch) based on MEMS gas sensors has been developed. The methodology followed to validate the performance of the prototype was as follows: firstly, the detection capability was tested by measuring carbon dioxide and methane at different concentrations, resulting in low detection limits; secondly, several experiments were performed to test the discrimination capability against gases such as toluene, xylene, and ethylbenzene. principal component analysis of the data showed good separation and discrimination between the gases measured.

Risk assessment of Benzene, Toluene, Ethyl benzene, and Xylene (BTEX) in the atmospheric air around the world: A review

Volatile organic compounds, such as BTEX, have been the subject of numerous debates due to their detrimental effects on the environment and human health. Human beings have had a significant role in the emergence of this situation. Even though US EPA, WHO, and other health-related organizations have set standard limits as unhazardous levels, it has been observed that within or even below these limits, constant exposure to these toxic chemicals results in negative consequences as well. According to these facts, various studies have been carried out all over the world - 160 of which are collected within this review article, so that experts and governors may come up with effective solutions to manage and control these toxic chemicals. The outcome of this study will serve the society to evaluate and handle the risks of being exposed to BTEX. In this review article, the attempt was to collect the most accessible studies relevant to risk assessment of BTEX in the atmosphere, and for the article to contain least bias, it was reviewed and re-evaluated by all authors, who are from different institutions and backgrounds, so that the insights of the article remain unbiased. There may be some limitations to consistency or precision in some points due to the original sources, however the attempt was to minimize them as much as possible.

Thermodynamically and Kinetically Enhanced Benzene Vapor Sensor Based on the Cu-TCPP-Cu MOF with Extremely Low Limit of Detection

As a carcinogenic and highly neurotoxic hazardous gas, benzene vapor is particularly difficult to be distinguished in BTEX (benzene, toluene, ethylbenzene, xylene) atmosphere and be detected in low concentrations due to its chemical inertness. Herein, we develop a depth-related pore structure in Cu-TCPP-Cu to thermodynamically and kinetically enhance the adsorption of benzene vapor and realize the detection of ultralow-temperature benzene gas. We find that the in-plane π electronic nature and proper pore sizes in Cu-TCPP-Cu can selectively induce the adsorption and diffusion of BTEX. Interestingly, the theoretical calculations (including density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations) exhibit that benzene molecules are preferred to adsorb and array as a consecutive arrangement mode in the Cu-TCPP-Cu pore, while the TEX (toluene, ethylbenzene, xylene) dominate the jumping arrangement model. The differences in distribution behaviors can allow adsorption and diffusion of more benzene molecules within limited room. Furthermore, the optimal pore-depth range (60-65 nm) of Cu-TCPP-Cu allows more exposure of active sites and hinders the gas-blocking process. The optimized sensor exhibits ultrahigh sensitivity to benzene vapor (155 Hz/μg@1 ppm), fast response time (less than 10 s), extremely low limit of detection (65 ppb), and excellent selectivity (83%). Our research thus provides a fundamental understanding to design and optimize two-dimensional metal-organic framework (MOF)-based gas sensors.

Mono and polycyclic aromatic hydrocarbons in waterpipe wastewater: Level and ecotoxicological risk assessment

Increasing of tobacco consumption around the world has led to the production of a large volume of waterpipe wastewater that enter the environment (e.g., coastal areas)and threaten aquatic creatures. However, until now, no research has been carried out on the amounts of monocyclic and polycyclic aromatic hydrocarbons (PAHs) in hookah wastewater. In the current study, the levels of PAHs and BTEX compounds in waterpipe wastewater resulting from the use of different tobacco brands were determined and their eco-toxicological effects were also evaluated. The mean levels of ƩPAHs in waterpipe wastewater of Al Tawareg, Al-Fakher, Nakhla, Tangiers and traditional tobacco brands samples were 3.48 ± 1.65, 3.33 ± 1.52, 3.08 ± 1.25, 2.41 ± 0.87 and 0.70 ± 0.13 μg/L, respectively. The mean levels of ƩBTEX in waterpipe wastewater of Al Tawareg, Al-Fakher, Nakhla, Tangiers and traditional tobacco brands samples were also 2.53 ± 0.61, 2.65 ± 0.78, 2.51 ± 0.72, 2.35 ± 0.56, and 0.78 ± 0.12 μg/L, respectively. The maximum level of PAHs and BTEX compounds in all brands/flavors samples were for naphthalene (Naph) and toluene, respectively. The concentrations of some PAHs (fluoranthene (Flrt), anthracene (Ant), benzo(b)fluoranthene (BbF), benzo(b)fluoranthene (BkF), benzo (g,h,i)perylene (BghiP) and dibenzo (a, h) anthracene (DahA)) and BTEX compounds (benzene) in the waterpipe wastewater samples were more than recommended guidelines and standards by the international reputable organizations such as World Health Organization (WHO) for water quality. Waterpipe wastewater can be introduced as an important origin for the release of these dangerous contaminants into the environmental matrixes. Therefore, more stringent regulations should be considered for the safe disposal of such hazardous wastes including waterpipe wastewater.

Highly Sensitive and Selective Toluene Gas Sensors Based on ZnO Nanoflowers Decorated with Bimetallic AuPt

Efficient sensors for toluene detecting are urgently needed to meet people's growing demands for both environment and personal health. Metal oxide semiconductor (MOS)-based sensors have become brilliant candidates for the detection of toluene because of their superior performance over gas sensing. However, gas sensors based on pure MOS have certain limitations in selectivity, operating temperature, and long-term stability, which hinders their further practical applications. Noble metals (including Ag, Au, Pt, Pd, etc.) have the ability to enhance the performance of MOS-based sensors via surface functionalization. Herein, ZnO nanoflowers (ZNFs) modified with bimetallic AuPt are prepared for toluene detection through hydrothermal method. The response of a AuPt@ZNF-based gas sensor can reach 69.7 at 175 °C, which is 30 times, 9 times, and 10 times higher than that of the original ZNFs, Au@ZNFs, and Pt@ZNFs, respectively. Furthermore, the sensor also has a lower optimal operating temperature (175 °C), good stability (94% of previous response after one month), and high selectivity towards toluene, which is the result of the combined influence of the electronic and chemical sensitization of noble metals, as well as the unique synergistic effect of the AuPt alloy. In summary, AuPt@ZNF-based sensors can be further applied in toluene detection in practical applications.

Characterization of VOC emissions and health risk assessment in the plastic manufacturing industry

Volatile organic compounds (VOCs) significantly contribute to ozone pollution formation, and many VOCs are known to be harmful to human health. Plastic has become an indispensable material in various industries and daily use scenarios, yet the VOC emissions and associated health risks in the plastic manufacturing industry have received limited attention. In this study, we conducted sampling in three typical plastic manufacturing factories to analyze the emission characteristics of VOCs, ozone formation potential (OFP), and health risks for workers. Isopropanol was detected at relatively high concentrations in all three factories, with concentrations in organized emissions reaching 322.3 μg/m3, 344.8 μg/m3, and 22.6 μg/m3, respectively. Alkanes are the most emitted category of VOCs in plastic factories. However, alkenes and oxygenated volatile organic compounds (OVOCs) exhibit higher OFP. In organized emissions of different types of VOCs in the three factories, alkenes and OVOCs contributed 22.8%, 67%, and 37.8% to the OFP, respectively, highlighting the necessity of controlling them. The hazard index (HI) for all three factories was less than 1, indicating a low non-carcinogenic toxic risk; however, there is still a possibility of non-cancerous health risks in two of the factories, and a potential lifetime cancer risk in all of the three factories. For workers with job tenures exceeding 5 years, there may be potential health risks, hence wearing masks with protective capabilities is necessary. This study provides evidence for reducing VOC emissions and improving management measures to ensure the health protection of workers in the plastic manufacturing industry.

Appropriate control measure design by rapidly identifying risk areas of volatile organic compounds during the remediation excavation at an organic contaminated site

Many organic contaminated sites require on-site remediation; excavation remediation processes can release many volatile organic compounds (VOCs) which are key atmospheric pollutants. It is therefore important to rapidly identify VOCs during excavation and map their risk areas for human health protection. In this study, we developed a rapid analysis and assessment method, aiming to and reveal the real-time distribution of VOCs, evaluate their human health risks by quantitative models, and design appropriate control measures. Through on-site diagonal distribution sampling and analysis, VOCs concentration showed a decreasing trend within 5 m from the excavation point and then increased after 5 m with the increase in distance from the excavation point (p < 0.05). The concentrations of VOCs near the dominant wind direction were higher than the concentrations of surrounding pollutants. In contrast with conventional solid-phase adsorption (SPA) and thermal desorption gas chromatography-mass spectrometry (TD-GC/MS) methods for determining the composition and concentration of VOCs, the rapid measurement of VOCs by photo-ionization detector (PID) fitted well with the chemical analysis and modeling assessment of cancer/non-cancer risk. The targeting area was assessed as mild-risk (PID < 10 ppm), moderate-risk (PID from 10 to 40 ppm), and heavy-risk (PID > 40 ppm) areas. Similarly, the human health risks also decreased gradually with the distance from the excavation point, with the main risk area located in the dominant wind direction. The results of rapid PID assessment were comparable to conventional risk evaluation, demonstrating its feasibility in rapidly identifying VOCs releases and assessing the human health risks. This study also suggested appropriate control measures that are important guidance for personal protection during the remediation excavation process.

Toxicological Effects of Inhaled Crude Oil Vapor

PURPOSE OF REVIEW

The purpose of this review is to assess the toxicological consequences of crude oil vapor (COV) exposure in the workplace through evaluation of the most current epidemiologic and laboratory-based studies in the literature.

RECENT FINDINGS

Crude oil is a naturally occuring mixture of hydrocarbon deposits, inorganic and organic chemical compounds. Workers engaged in upstream processes of oil extraction are exposed to a number of risks and hazards, including getting crude oil on their skin or inhaling crude oil vapor. There have been several reports of workers who died as a result of inhalation of high levels of COV released upon opening thief hatches atop oil storage tanks. Although many investigations into the toxicity of specific hydrocarbons following inhalation during downstream oil processing have been conducted, there is a paucity of information on the potential toxicity of COV exposure itself. This review assesses current knowledge of the toxicological consequences of exposures to COV in the workplace.

Increased oxidative stress in shoe industry workers with low-level exposure to a mixture of volatile organic compounds

This study aimed to assess the redox status and trace metal levels in 49 shoe industry workers (11 men and 38 women) occupationally exposed to a mixture of volatile organic compounds (VOCs), which includes aliphatic hydrocarbons, aromatic hydrocarbons, ketones, esters, ethers, and carboxylic acids. All measured VOCs were below the permitted occupational exposure limits. The control group included 50 unexposed participants (25 men and 25 women). The following plasma parameters were analysed: superoxide anion (O2 •-), advanced oxidation protein products (AOPP), total oxidative status (TOS), prooxidant-antioxidant balance (PAB), oxidative stress index (OSI), superoxide dismutase (SOD) and paraoxonase-1 (PON1) enzyme activity, total SH group content (SHG), and total antioxidant status (TAS). Trace metal levels (copper, zinc, iron, magnesium, and manganese) were analysed in whole blood. All oxidative stress and antioxidative defence parameters were higher in the exposed workers than controls, except for PON1 activity. Higher Fe, Mg, and Zn, and lower Cu were observed in the exposed vs control men, while the exposed women had higher Fe and lower Mg, Zn, and Cu than their controls. Our findings confirm that combined exposure to a mixture of VOCs, even at permitted levels, may result in additive or synergistic adverse health effects and related disorders. This raises concern about current risk assessments, which mainly rely on the effects of individual chemicals, and calls for risk assessment approaches that can explain combined exposure to multiple chemicals.

Current trends on dry photocatalytic oxidation technology for BTX removal: Viable light sources and highly efficient photocatalysts

One of the main gaseous pollutants released by chemical production industries are benzene, toluene and xylene (BTX). These dangerous gases require immediate technology to combat them, as they put the health of living organisms at risk. The development of heterogeneous photocatalytic oxidation technology offers several viewpoints, particularly in gaseous-phase decontamination without an additional supply of oxidants in air at atmospheric pressure. However, difficulties such as low quantum efficiency, ability to absorb visible light, affinity towards CO2 and H2O synthesis, and low stability continue to limit its practical use. This review presents recent advances in dry-phase heterogeneous photodegradation as an advanced technology for the practical removal of BTX molecules. This review also examines the impact of low-cost light sources, the roles of the active sites of photocatalysts, and the feasible concentration range of BTX molecules. Numerous studies have demonstrated a significant improvement in the efficiency of the photodegradation of volatile organic compounds by enhancing the photocatalytic reactor system and other factors, such as humidity, temperature, and flow rate. The mechanism for BTX photodegradation based on density functional theory (DFT), electron paramagnetic resonance (EPR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) investigations is also discussed. Finally, the present research complications and anticipated future developments in the field of heterogeneous photocatalytic oxidation technology are discussed.

Volatile organic compounds: A threat to the environment and health hazards to living organisms - A review

Volatile organic compounds (VOCs) are the organic compounds having a minimum vapor pressure of 0.13 kPa at standard temperature and pressure (293 K, 101 kPa). Being used as a solvent for organic and inorganic compounds, they have a wide range of applications. Most of the VOCs are non-biodegradable and very easily become component of the environment and deplete its purity. It also deteriorates the water quality index of the water bodies, impairs the physiology of living beings, enters the food chain by bio-magnification and degrades, decomposes and manipulates the physiology of living organisms. To unveil the adverse impacts of volatile organic compounds (VOCs) and their rapid eruption and interference in the living world, a review has been designed. This review presents an insight into the currently available VOCs, their sources, applications, sampling methods, analytic procedures, imposition on the health of aquatic and terrestrial communities and their contamination of the environment. Elaboration has been done on representation of toxicological effects of VOCs on vertebrates, invertebrates, and birds. Subsequently, the role of environmental agencies in the protection of environment has also been illustrated.

MOF-801 based solid phase microextraction fiber for the monitoring of indoor BTEX pollution

Benzene, toluene, ethylbenzene and xylenes (BTEX) are some of the better-known indoor air pollutants, for which effective monitoring is important. The analysis of BTEX can be performed by different type of solid phase microextraction (SPME) fibers. This study presents a proposal for a low cost, convenient and environmentally friendly analytical method for the determination of BTEX in air samples using custom made SPME fibers. In this context, custom made metal organic frameworks (MOF-801) were coated on a stainless-steel wire for SPME fiber preparation. The analysis of BTEX was performed by introducing SPME fiber into an analyte-containing Tedlar bag in steady-state conditions. After the sampling step, the analytes were analyzed using gas chromatography mass spectrometry in selected ion monitoring mode. Parameters that affect the analysis results were optimized; these include desorption temperature and time, preconditioning time, extraction temperature and time, and sample volume. Under optimized conditions, analytical figure of merits of developed method were obtained, including limits of detection (LOD) (0.012 - 0.048 mg/m3), linear ranges (0.041-18 mg/m3), intraday and interday repeatability (2.08 - 4.04% and 3.94 - 6.35%), and fiber to fiber reproducibility (7.51 - 11.17%). The proposed method was successfully applied to real air samples with an acceptable recovery values between 84.5% and 110.9%. The developed method can be applied for the effective monitoring of BTEX.

Utilization of a Low-Cost Sensor Array for Mobile Methane Monitoring

The use of low-cost sensors (LCSs) for the mobile monitoring of oil and gas emissions is an understudied application of low-cost air quality monitoring devices. To assess the efficacy of low-cost sensors as a screening tool for the mobile monitoring of fugitive methane emissions stemming from well sites in eastern Colorado, we colocated an array of low-cost sensors (XPOD) with a reference grade methane monitor (Aeris Ultra) on a mobile monitoring vehicle from 15 August through 27 September 2023. Fitting our low-cost sensor data with a bootstrap and aggregated random forest model, we found a high correlation between the reference and XPOD CH4 concentrations (r = 0.719) and a low experimental error (RMSD = 0.3673 ppm). Other calibration models, including multilinear regression and artificial neural networks (ANN), were either unable to distinguish individual methane spikes above baseline or had a significantly elevated error (RMSDANN = 0.4669 ppm) when compared to the random forest model. Using out-of-bag predictor permutations, we found that sensors that showed the highest correlation with methane displayed the greatest significance in our random forest model. As we reduced the percentage of colocation data employed in the random forest model, errors did not significantly increase until a specific threshold (50 percent of total calibration data). Using a peakfinding algorithm, we found that our model was able to predict 80 percent of methane spikes above 2.5 ppm throughout the duration of our field campaign, with a false response rate of 35 percent.

Health damage assessment of commuters and staff in the metro system based on field monitoring-A case study of Nanjing

Introduction

The metro has emerged as a major mode of transportation. A significant number of commuters and staff in the metro system are exposed to air pollutants because of its shielded environment, and substantial health damage requires quantitative assessment. Previous studies have focused on comparing the health impacts among different transportation modes, overlooking the specific population characteristics and pollutant distribution in metro systems.

Methods

To make improvements, this study implements field monitoring of the metro's air environment utilizing specialized instruments and develops a health damage assessment model. The model quantifies health damage of two main groups (commuters and staff) in metro systems at three different areas (station halls, platforms, and metro cabins) due to particulate matter 10 and benzene series pollution.

Conclusion

A case study of Nanjing Metro Line 3 was conducted to demonstrate the applicability of the model. Health damage at different metro stations was analyzed, and the health damage of commuters and staff was assessed and compared. This study contributes to enhancing research on health damage in the metro systems by providing a reference for mitigation measures and guiding health subsidy policies.

Chemical, ecotoxicological, cytotoxic, and mutagenic evaluation of gelling agents used in the production of 70% alcohol gel

With COVID-19, there has been an increase in the use of gelling agents for hand sanitizer production, and as a result, the release of this product into wastewater could induce impacts and adverse reactions in living organisms. Thus, ecotoxicological and cytotoxicological assessments of gelling agents with test organisms from different trophic levels are necessary to assess their environmental safety. For this, seven cellulose-based gelling agents and a polyacrylic acid derivative (C940) were selected for tests with Artemia salina. The most toxic agent was tested on Allium cepa to assess cytotoxicity. The volatile compounds of the gelling agents were analyzed. Cellulose-based gelling agents were not considered toxic according to their LC50, but C940 presented moderate toxicity to A. salina and cytotoxicity to Allium cepa, but without mutagenicity. In addition, C940 contained cyclohexane as a volatile compound. Thus, cellulose-based gelling agents are better environmental options than carbomer for 70% alcohol gel sanitizer.

Hydrothermal Synthesis of MnO2 Microspheres and Their Degradation of Toluene

Various urchin-like MnO2 materials were obtained with a facile hydrothermal method through controlling the Mn precursor, reaction time, and reaction temperature. The property of MnO2 materials was characterized by scanning electron microscopy, X-ray diffraction, and H2 temperature-programmed reduction. The results showed that the Mn precursor could significantly impact the morphology of as-prepared MnO2. When the precursor was Mn(CH3COO)2·4H2O, the MnO2 morphology consisted of tennis-like microspheres assembled by nanorods. While the precursor was MnCl2·4H2O, the sample morphology was a chestnut shell, and the samples were sea urchin microspheres, as the precursor was MnSO4·H2O. At the same time, the morphology of MnO2 was affected by hydrothermal time and temperature. The nanoneedles on the microsphere surface gradually lengthened with increasing hydrothermal time and hydrothermal temperature, until nanowires were formed. MnO2 crystallinity was also influenced by hydrothermal temperature. It was γ-MnO2 as the temperature was 50 and 80 °C while evolved to be α-MnO2 and β-MnO2 when the temperature increased to 140 °C. As MnO2 (MnO2-1 h, MnO2-2 h, MnO2-4 h, and MnO2-6 h) was prepared to degrade toluene, all the samples could completely catalyze toluene at the temperature of 225 °C. However, the MnO2-4 h showed the best catalytic effect at a lower temperature.

Volatile organic compounds and ionic substances contamination in cell processing facilities during rest period; a preliminary assessment of exposure to cell processing operators

Introduction

Cell processing operators (CPOs) use a variety of disinfectants that vaporize in the workspace environment. These disinfectants can induce allergic reactions in CPOs, due to their long working hours at cell processing facilities (CPFs). Ionic substances such as CH₃COO^- generated from peracetic acid, nitrogen oxides (NOx) and sulfur oxides (SOx) from outdoor environment are also known to pollute air. Therefore, our objective was to assess the air quality in CPFs and detect volatile organic compounds (VOCs) from disinfectants and building materials, and airborne ionic substances from outdoor air.

Methods

Sampling was conducted at three CPFs: two located in medical institutions and one located at a different institution. Air samples were collected using a flow pump. Ion chromatographic analysis of the anionic and cationic compounds was performed. For VOC analysis, a thermal desorption analyzer coupled with capillary gas chromatograph and flame ionization detector was used.

Results

Analysis of the ionic substances showed that Cl^-, NOx, and SOx, which were detected in large amounts in the outdoor air, were relatively less in the CPFs. Ethanol was detected as the main component in the VOC analysis. Toluene was detected at all sampling points. As compared to the other environments, air in the incubator contained larger amounts of VOCs, that included siloxane, tetradecane, and aromatics.

Conclusions

No VOCs or ionic substances of immediate concern to the health of the CPOs were detected during the non-operating period. However, new clinical trials of cell products are currently underway in Japan, and a variety of new cell products are expected to be approved. With an increase in cell processing, health risks to CPOs that have not been considered previously, may become apparent. We should continue to prepare for the future expansion of the industry using a scientific approach to collect various pieces of information and make it publicly available to build a database.

Hydrogen-Assisted Photoionization and Its Use in Promoting Mass Spectrometry Analysis of VOCs

As a simple soft ionization method, photoionization (PI) is often coupled with mass spectrometry (MS) for the direct analysis of volatile organic compounds (VOCs). PI enables selective ionization of analytes, but the ion yield is generally not high due to the limited light intensity of the ultraviolet lamp. Here, a hydrogen-assisted photoionization (HAPI) strategy was developed and integrated into a miniature ion trap mass spectrometer. In particular, hydrogen was introduced as a versatile buffer gas to facilitate both photoionization and ion trap operation. This can increase the ion yields by up to 2 orders of magnitude compared to conventional PI-MS, with a low hydrogen consumption (less than 100 μL) for each analysis. The generation of protonated ions indicates a specific photochemical process in HAPI, which has also been studied and initially revealed. The detection of various VOCs and plant volatile gases confirmed the versatility and practicality of the HAPI technology.

Evaluating changes in firefighter urinary metabolomes after structural fires: an untargeted, high resolution approach

Firefighters have elevated rates of urinary tract cancers and other adverse health outcomes, which may be attributable to environmental occupational exposures. Untargeted metabolomics was applied to characterize this suite of environmental exposures and biological changes in response to occupational firefighting. 200 urine samples from 100 firefighters collected at baseline and two to four hours post-fire were analyzed using untargeted liquid-chromatography and high-resolution mass spectrometry. Changes in metabolite abundance after a fire were estimated with fixed effects linear regression, with false discovery rate (FDR) adjustment. Partial least squares discriminant analysis (PLS-DA) was also used, and variable important projection (VIP) scores were extracted. Systemic changes were evaluated using pathway enrichment for highly discriminating metabolites. Metabolome-wide-association-study (MWAS) identified 268 metabolites associated with firefighting activity at FDR q < 0.05. Of these, 20 were annotated with high confidence, including the amino acids taurine, proline, and betaine; the indoles kynurenic acid and indole-3-acetic acid; the known uremic toxins trimethylamine n-oxide and hippuric acid; and the hormone 7a-hydroxytestosterone. Partial least squares discriminant analysis (PLS-DA) additionally implicated choline, cortisol, and other hormones. Significant pathways included metabolism of urea cycle/amino group, alanine and aspartate, aspartate and asparagine, vitamin b3 (nicotinate and nicotinamide), and arginine and proline. Firefighters show a broad metabolic response to fires, including altered excretion of indole compounds and uremic toxins. Implicated pathways and features, particularly uremic toxins, may be important regulators of firefighter's increased risk for urinary tract cancers.

Paintable Silicone-Based Corrugated Soft Elastomeric Capacitor for Area Strain Sensing

Recent advances in soft polymer materials have enabled the design of soft machines and devices at multiple scales. Their intrinsic compliance and robust mechanical properties and the potential for a rapid scaling of the production process make them ideal candidates for flexible and stretchable electronics and sensors. Large-area electronics (LAE) made from soft polymer materials that are capable of sustaining large deformations and covering large surfaces and are applicable to complex and irregular surfaces and transducing deformations into readable signals have been explored for structural health monitoring (SHM) applications. The authors have previously proposed and developed an LAE consisting of a corrugated soft elastomeric capacitor (cSEC). The corrugation is used to engineer the directional strain sensitivity by using a thermoplastic styrene-ethylene-butadiene-styrene (SEBS). A key limitation of the SEBS-cSEC technology is the need of an epoxy for reliable bonding of the sensor onto the monitored surface, mainly attributable to the sensor's fabrication process that comprises a solvent that limits its direct deployment through a painting process. Here, with the objective to produce a paintable cSEC, we study an improved solvent-free fabrication method by using a commercial room-temperature-vulcanizing silicone as the host matrix. The matrix is filled with titania particles to form the dielectric layer, yielding a permittivity of 4.05. Carbon black powder is brushed onto the dielectric and encapsulated with the same silicone to form the conductive stretchable electrodes. The sensor is deployed by directly painting a layer of the silicone onto the monitored surface and then depositing the parallel plate capacitor. The electromechanical behavior of the painted silicone-cSEC was characterized and exhibited good linearity, with an R2 value of 0.9901, a gauge factor of 1.58, and a resolution of 70 με. This resolution compared well with that of the epoxied SEBS-cSEC reported in previous work (25 με). Its performance was compared against that of its more mature version, the SEBS-cSEC, in a network configuration on a cantilever plate subjected to a step-deformation and to free vibrations. Results showed that the performance of the painted silicone-sCEC compared well with that of the SEBS-cSEC, but that the use of a silicone paint instead of an epoxy could be responsible for larger noise and the under-estimation of the dominating frequency by 6.7%, likely attributable to slippage.

Summer and winter variations of BTEX concentrations in an oil refinery complex and health risk assessment based on Monte-Carlo simulations

The summer and winter concentrations of BTEX pollutants were investigated in various workplaces of an oil Refinery, Iran. In total 252 air samples from the breathing zones of the following employees were collected: supervisors, safetymen, repairmen, site men, and all workers. Carcinogenic and non-carcinogenic risk values were calculated based on the USEPA methodology using Monte Carlo simulations. BTEX concentrations were higher in the summer than in the winter season for all workstations, especially for toluene and ethylbenzene. The mean values of exposure to benzene for repairmen and site men were higher than threshold limit value of 1.60 mg/m3 for both seasons. Non-carcinogenic risk (HQ) values calculated for summer season for benzene, ethylbenzene, and xylene in all workstations, as well as for toluene for repairmen and site men exceeded acceptable level of 1. In winter season the mean HQ values for benzene and xylene in all workstations, for toluene for repairmen and site men, and for ethylbenzene for supervisors, repairmen, and site men were also > 1. For all workstations definite carcinogenic risk was indicated as calculated LCR values for benzene and ethylbenzene exposure were higher than 1 × 10-4 in both summer and winter seasons.

BTEX and PAH contributions to Lake Kinneret water: a seasonal-based study of volatile and semi-volatile anthropogenic pollutants in freshwater sources

Benzene , toluene, ethylbenzene, and xylenes (BTEX) BTEX molecules are toxic components, ubiquitous in the environment, often found in concentrations- a few orders of magnitude higher than the well-studied PAHs levels. This fact is demonstrated in either crude oil, fuels, water, and air samples. BTEX studies focus mainly on the airborne levels of these molecules, while their waterborne presence is understudied. In this study, BTEX levels were assessed at Lake Kinneret, Israel. As a result, 0-1.5 ppb of BTEX was recorded in five stations (2021-2022). Elevated BTEX levels (3-10 ppb) were recorded at the northern rivers nourishing this lake, implying the existence of remote polluting sources. Transect air samplings of BTEX conducted at the lake next to the bathing season of 2021 revealed airborne BTEX levels between 0.8 and 10 µg/m³, peaking up close to the bathing season, yet inconsistent with the BTEX water level trend. Lake water samples collected next to Tiberias city outfalls following the "Carmel" rainstorm showed elevated concentrations of BTEX up to 35 ppb and PAHs up to 0.47 ppb with an urban isotopic signal. The remote station's PAHs levels were less than one order of magnitude, with a distinct rural isotopic signal. Additionally, a human-specific microbial marker revealed increased sewer contributions at some of the urbansites. The results of this study show that a wide area dispersion of low atmospheric BTEX levels exists in the lake's perimeter. The dispersion rate is most likely influenced by season-based factors, e.g., motors and biomass fires. The unstudied waterborne BTEX levels in this lake are influenced by rivers, city runoff, and other yet unknown factors that may contribute to the sedimentation of these components. This process may result in a chronic pollution state. Despite the BTEX's medium-low solubility and high volatility, its under-evaluated waterborne transportation may lead to high toxic levels following bioaccumulation.

Phytoremediation for the indoor environment: a state-of-the-art review

Poor indoor air quality has become of particular concern within the built environment due to the time people spend indoors, and the associated health burden. Volatile organic compounds (VOCs) off-gassing from synthetic materials, nitrogen dioxide and harmful outdoor VOCs such benzene, toluene, ethyl-benzene and xylene penetrate into the indoor environment through ventilation and are the main contributors to poor indoor air quality with health effects. A considerable body of literature over the last four decades has demonstrate the removal of gaseous contaminants through phytoremediation, a technology that relies on plant material and technologies to remediate contaminated air streams. In this review we present a state-of-the-art on indoor phytoremediation over the last decade. Here we present a review of 38 research articles on both active and passive phytoremediation, and describe the specific chemical removal efficiency of different systems. The literature clearly indicates the efficacy of these systems for the removal of gaseous contaminants in the indoor environment, however it is evident that the application of phytoremediation technologies for research purposes in-situ is currently significantly under studied. In addition, it is common for research studies to assess the removal of single chemical species under controlled conditions, with little relevancy to real-world settings easily concluded. The authors therefore recommend that future phytoremediation research be conducted both in-situ and on chemical sources of a mixed nature, such as those experienced in the urban environment like petroleum vapour, vehicle emissions, and mixed synthetic furnishings off-gassing. The assessment of these systems both in static chambers for their theoretical performance, and in-situ for these mixed chemical sources is essential for the progression of this research field and the widespread adoption of this technology.

Expression level and function analysis of serum miRNAs in workers with occupational exposure to benzene series

Benzene series are ubiquitous in industrial production and daily life, and can have an impact on health even at low concentrations. miRNAs have been proved to be a biomarker of a variety of diseases and carcinogens. The purpose of this study was to explore the distribution characteristics and biological function of miRNAs in subjects exposed to benzene series. In this study, serum miRNAs were measured in 247 occupationally exposed subjects and 256 controls. The relationship between cumulative exposure dose of benzene series and miRNAs was analyzed by Generalized linear model, Spearman's rank correlation, and chi-square test for trend. The function of MiRNAs target gene was analyzed by means of bioinformatics method. The results showed that the expressions of miR-181a-5p, 221-3p, 223-3p, and 342-3p were down-regulated, whilst the expression of miR-638 was up-regulated in the occupational exposure group. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 showed dose-response relationship with benzene series, and were closely related to multiple tumor pathways. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 may be involved in the carcinogenic process of benzene series, and can be used to evaluate the early biological effects and monitor the exposure level of benzene series. miRNAs are potential biomarkers of benzene series exposure.

Exposure assessment of wastewater treatment plant employees to BTEX: a biological monitoring approach

To monitor employees' work safety and exposure against air contaminants, Trans, trans-muconic acid, Hippuric acid, Methyl hippuric acid, Mandelic acid and Phenylglyoxylic acid can be used as reliable biomarkers of exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. This study aims to determine the level of urinary metabolites of BTEX compounds using biological monitoring in the employees of a wastewater treatment plant (WWTP) in the south of Iran. The study was performed on 56 employees of the WWTP of one of the southern cities of Iran in 2020. Urine samples (n total = 112) consisting of 60 samples of employees working in the operation section (exposed group) and 52 samples of employees working in the administrative section (control group) in the WWTP were collected before and at the end of their shift. The mean concentration of urinary metabolites of BTEX of both groups ranged from 546.43 (μg/g cr) for trans, trans-muconic acid to 0.006 (μg/g cr) for methyl hippuric acid, which indicates that most of the evaluated metabolites showed a higher concentration than their occupational threshold limit value urine (p < 0.05). Regression analysis results showed a significant correlation (p < 0.05) between age and utilization of flame heaters with changes in the measured BTEX metabolites in the urine. The results of this study illustrate that WWTPs should be considered as one of the workplaces with potential sources of BTEX exposure for employees. Future investigations are recommended to perform itemized appraisals of BTEX intake sources, particularly in employees of the operational sections of WWTP.

Exposure to Crude Oil-Related Volatile Organic Compounds Associated with Lung Function Decline in a Longitudinal Panel of Children

BACKGROUND

Children in the affected area were exposed to large amounts of volatile organic compounds (VOCs) from the Hebei Spirit oil spill accident.

OBJECTIVES

We investigated the lung function loss from the exposure to VOCs in a longitudinal panel of 224 children 1, 3, and 5 years after the VOC exposure event.

METHODS

Atmospheric estimated concentration of total VOCs (TVOCs), benzene, toluene, ethylbenzene, and xylene for 4 days immediately after the accident were calculated for each village (n = 83) using a modeling technique. Forced expiratory volume in 1 s (FEV₁) as an indicator of airway status was measured 1, 3, and 5 years after the exposure in 224 children 4~9 years of age at the exposure to the oil spill. Multiple linear regression and linear mixed models were used to evaluate the associations, with adjustment for smoking and second-hand smoke at home.

RESULTS

Among the TVOCs (geometric mean: 1319.5 mg/m³·4 d), xylene (9.4), toluene (8.5), ethylbenzene (5.2), and benzene (2.0) were dominant in the order of air concentration level. In 224 children, percent predicted FEV₁ (ppFEV₁), adjusted for smoking and second-hand smoke at home, was 100.7% after 1 year, 96.2% after 3 years, and 94.6% after 5 years, and the loss over the period was significant (p < 0.0001). After 1 and 3 years, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁. After 5 years, the associations were not significant. Throughout the 5 years' repeated measurements in the panel, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁.

CONCLUSIONS

Exposure to VOCs from the oil spill resulted in lung function loss among children, which remained significant up to 5 years after the exposure.

Occupational Exposures and Health Risks of Benzene, Toluene, and Xylenes (BTX) in Automobile Repair Industry in Beijing City, China

This study aimed to evaluate the occupational health risks of benzene, toluene, and xylenes (BTX) exposure in the automobile repair industry in Beijing city in China. The concentrations of BTX were monitored at 140 operating positions of 51 randomly selected automobile repair enterprises in 2018. Samples analysis showed that all monitoring concentrations were not higher than the occupational exposure limits. The long-term exposure concentration ranges of benzene, toluene, and xylenes were 0.1 to 0.3, 0.1 to 49.7, and 0.2 to 49.5 mg/m³, respectively. The short-term exposure concentration ranges of benzene, toluene, and xylenes were 0.1 to 0.3, 0.1 to 98.7, and 0.2 to 100.0 mg/m³, respectively. But assessment results revealed unneglectable occupational health risks, especially the combined health risks of BTX exposure. Thereafter, effective control and improvement measures were put forward, including strengthening the management of the production, sale, and use of vehicle paints and coatings; improving ventilation; and implementing hierarchical management measures for occupational health risks.

Phytotoxicity of particulate matter from controlled burning of different plastic waste types

According to careful estimations, open burning of plastic waste affects app. 2 billion people worldwide. While human health risks have become more and more obvious, much less information is available on the phytotoxicity of these emissions. In our study phytotoxicity of particulate matter samples generated during controlled combustion of different plastic waste types such as polyvinyl chloride (PVC), polyurethane (PUR), polypropylene (PP), polystyrene (PS) and polyethylene (PE) was evaluated based on peroxidase levels. While different samples showed different concentration-effect relationship patterns, higher concentration(s) caused decreased peroxidase activities in each sample indicating serious damage.

Inhibition of Phenol from Entering into Condensed Freshwater by Activated Persulfate during Solar-Driven Seawater Desalination

Recently, solar-driven seawater desalination has received extensive attention since it can obtain considerable freshwater by accelerating water evaporation at the air-water interface through solar evaporators. However, the high air-water interface temperature can cause volatile organic compounds (VOCs) to enter condensed freshwater and result in water quality safety risk. In this work, an antioxidative solar evaporator, which was composed of MoS₂ as the photothermal material, expandable polyethylene (EPE) foam as the insulation material, polytetrafluoroethylene (PTFE) plate as the corrosion resistant material, and fiberglass membrane (FB) as the seawater delivery material, was fabricated for the first time. The activated persulfate (PS) methods, including peroxymonosulfate (PMS) and peroxodisulfate (PDS), were applied to inhibit phenol from entering condensed freshwater during desalination. The distillation concentration ratio of phenol (R_D) was reduced from 76.5% to 0% with the addition of sufficient PMS or PDS, which means that there was no phenol in condensed freshwater. It was found that the Cl^- is the main factor in activating PMS, while for PDS, light, and heat are the dominant. Compared with PDS, PMS can make full utilization of the light, heat, Cl^- at the evaporator's surface, resulting in more effective inhibition of the phenol from entering condensed freshwater. Finally, though phenol was efficiently removed by the addition of PMS or PDS, the problem of the formation of the halogenated distillation by-products in condensed freshwater should be given more attention in the future.

Risk assessment and dose-effect of co-exposure to benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) on pulmonary function: A cross-sectional study

Inhalation is the most frequent route and the lung is the primary damaged organ for human exposure to benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS). However, there is limited information on the risk and dose-effect of the BTEXS mixture on pulmonary function, particularly the overall effect. We conducted a cross-sectional study in a petrochemical plant in southern China. Spirometry and cumulative exposure dose (CED) of BTEXS were used to measure lung function and exposure levels for 635 workers in 2020, respectively. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were tested and interpreted as percentages to predicted values [FVC or FEV₁% predicted], and FEV₁ to FVC ratio [FEV₁/FVC (%)]. We found the reduction in FVC% predicted and the risk of lung ventilation dysfunction (LVD) and its two subtypes (mixed and restrictive ventilation dysfunction, MVD, and MVD) were significantly associated with BTEXS individuals. In addition, pulmonary function damage associated with BTEXS was modified by the smoking status and age. Generalized weighted quantile sum (gWQS) regressions were used to estimate the overall dose-effect on lung function damage induced by the BTEXS mixture. Our results show wqs, an index of weighted quartiles for BTEXS, was potentially associated with the reduction in FVC and FEV₁% predicted with the coefficients [95% confidence intervals (CI)] between -1.136 (-2.202, -0.070) and -1.230 (-2.265, -0.195). Odds ratios (ORs) and 95% CIs for the wqs index of LVD, MVD, and RVD were 1.362 (1.129, 1.594), 1.323 (1.084, 1.562), and 1.394 (1.096, 1.692), respectively. Furthermore, xylene, benzene, and toluene in the BTEXS mixture potentially contribute to the development of lung function impairment. Our novel findings demonstrated the dose-response relationships between pulmonary function impairment and the BTEXS mixture and disclosed the potential key pollutants in the BTEXS mixture.

Association between exposure to a mixture of benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) and small airways function: A cross-sectional study

BACKGROUND

Lung is one of the primary target organs of benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS). Small airways dysfunction (SAD) might be a sensitive indicator of early chronic respiratory disease. Here, we explored the relationships between exposure to BTEXS and small airways function, and identified the priority control pollutants in BTEXS mixtures.

METHODS

635 petrochemical workers were recruited. Standard spirometry testing was conducted by physicians. The cumulative exposure dose (CED) of BTEXS for each worker was estimated. The peak expiratory flow (PEF), forced expiratory flow between 25 and 75% of forced vital capacity (FEF25∼75%), and the expiratory flow rate found at 25%, 50%, and 75% of the remaining exhaled vital capacity (MEF25%, MEF50%, and MEF75%) were measured. SAD was also evaluated based on measured parameters. The associations between exposure to BTEXS individuals or mixtures and small airways function were evaluated using generalized linear regression models (GLMs) and quantile g-computation models (qgcomp). Meanwhile, the weights of each homolog in the association were estimated.

RESULTS

The median CED of BTEXS are 9.624, 19.306, 24.479, 28.210, and 46.781 mg/m³·years, respectively. A unit increase in ln-transformed styrene CED was associated with a decrease in FEF25∼75% and MEF50% based on GLMs. One quartile increased in BTEXS mixtures (ln-transformed) was significantly associated with a 0.325-standard deviation (SD) [95% confidence interval (CI): -0.464, -0.185] decline in FEF25∼75%, a 0.529-SD (95%CI: -0.691, -0.366) decline in MEF25%, a 0.176-SD (95%CI: -0.335, -0.017) decline in MEF75%, and increase in the risk of abnormal of SAD [risk ratios (95%CI): 1.520 (95%CI: 1.143, 2.020)]. Benzene and styrene were the major chemicals in BTEXS for predicting the overall risk of SAD.

CONCLUSION

Our novel findings demonstrate the significant association between exposure to BTEXS mixture and small airways function decline and the potential roles of key homologs (benzene and styrene) in SAD.

Computational Investigations of Metal-Organic Frameworks as Sorbents for BTEX Removal

Sequestration of aromatic volatile organic compounds (VOCs) via metal-organic frameworks (MOFs) as sorbents is a viable means of environmental preservation. In this investigation, we shed light on the key features associated with MOFs that govern the selective uptake of a subclass of VOCs containing benzene, toluene, ethylbenzene, and xylenes (BTEX). We investigate, through a multistep computational framework including ab initio electronic structure and classical molecular dynamics simulations, the energetic and dynamical properties associated with BTEX capture in three MOFs: HKUST-1, ZIF-8, and MIL-53. Our work demonstrates the importance of considering both static and dynamical properties upon introduction of guest molecules in such computational investigations. We elucidate the key geometric factors associated with efficient capture of BTEX compounds and highlight possible postsynthetic modifications that can be used to produce next generation sorbents for BTEX capture.

Hematological Effects and Benchmark Doses of Long-Term Co-Exposure to Benzene, Toluene, and Xylenes in a Follow-Up Study on Petrochemical Workers

Benzene, toluene, and xylenes (BTX) commonly co-exist. Exposure to individual components and BTX-rich mixtures can induce hematological effects. However, the hematological effects of long-term exposure to BTX are still unclear, and respective reference levels based on empirical evidence should be developed. We conducted a follow-up study in BTX-exposed petrochemical workers. Long-term exposure levels were quantified by measuring cumulative exposure (CE). Generalized weighted quantile sum (WQS) regression models and Benchmark Dose (BMD) Software were used to evaluate their combined effects and calculate their BMDs, respectively. Many hematologic parameters were significantly decreased at the four-year follow-up (p < 0.05). We found positive associations of CE levels of benzene, toluene, and xylene with the decline in monocyte counts, lymphocyte counts, and hematocrit, respectively (β > 0.010, Ptrend < 0.05). These associations were stronger in subjects with higher baseline parameters, males, drinkers, or overweight subjects (Pinteraction < 0.05). BTX had positive combined effects on the decline in monocyte counts, red-blood-cell counts, and hemoglobin concentrations (Ptrend for WQS indices < 0.05). The estimated BMDs for CE levels of benzene, toluene, and xylene were 2.138, 1.449, and 2.937 mg/m3 × year, respectively. Our study demonstrated the hematological effects of long-term BTX co-exposure and developed 8h-RELs of about 0.01 ppm based on their hematological effects.

Characteristics and Sources of Volatile Organic Compounds in the Nanjing Industrial Area

In this study, 56 volatile organic compounds species (VOCs) and other pollutants (NO, NO2, SO2, O3, CO and PM2.5) were measured in the northern suburbs of Nanjing from September 2014 to August 2015. The total volatile organic compound (TVOC) concentrations were higher in the autumn (40.6 ± 23.8 ppbv) and winter (41.1 ± 21.7 ppbv) and alkanes were the most abundant species among the VOCs (18.4 ± 10.0 ppbv). According to the positive matrix factorization (PMF) model, the VOCs were found to be from seven sources in the northern suburbs of Nanjing, including liquefied petroleum gas (LPG) sources, gasoline vehicle emissions, iron and steel industry sources, industrial refining coke sources, solvent sources and petrochemical industry sources. One of the sources was influenced by seasonal variations: it was a diesel vehicle emission source in the spring, while it was a coal combustion source in the winter. According to the conditional probability function (CPF) method, it was found that the main contribution areas of each source were located in the easterly direction (mainly residential areas, industrial areas, major traffic routes, etc.). There were also seasonal differences in concentration, ozone formation potential (OFP), OH radical loss rate (LOH) and secondary organic aerosols potential (SOAP) for each source due to the high volatility of the summer and autumn temperatures, while combustion increases in the winter. Finally, the time series of O3 and OFP was compared to that PM2.5 and SOAP and then they were combined with the wind rose figure. It was found that O3 corresponded poorly to the OFP, while PM2.5 corresponded well to the SOAP. The reason for this was that the O3 generation was influenced by several factors (NOx concentration, solar radiation and non-local transport), among which the influence of non-local transport could not be ignored.

Evaluating Phenotypic and Transcriptomic Responses Induced by Low-Level VOCs in Zebrafish: Benzene as an Example

Urban environments are plagued by complex mixtures of anthropogenic volatile organic compounds (VOCs), such as mixtures of benzene, toluene, ethylene, and xylene (BTEX). Sources of BTEX that drive human exposure include vehicle exhaust, industrial emissions, off-gassing of building material, as well as oil spillage and leakage. Among the BTEX mixture, benzene is the most volatile compound and has been linked to numerous adverse health outcomes. However, few studies have focused on the effects of low-level benzene on exposure during early development, which is a susceptible window when hematological, immune, metabolic, and detoxification systems are immature. In this study, we used zebrafish to conduct a VOC exposure model and evaluated phenotypic and transcriptomic responses following 0.1 and 1 ppm benzene exposure during the first five days of embryogenesis (n = 740 per treatment). The benzene body burden was 2 mg/kg in 1 ppm-exposed larval zebrafish pools and under the detection limit in 0.1 ppm-exposed fish. No observable phenotypic changes were found in both larvae except for significant skeletal deformities in 0.1 ppm-exposed fish (p = 0.01) compared with unexposed fish. Based on transcriptomic responses, 1 ppm benzene dysregulated genes that were implicated with the development of hematological system, and the regulation of oxidative stress response, fatty acid metabolism, immune system, and inflammatory response, including apob, nfkbiaa, serpinf1, foxa1, cyp2k6, and cyp2n13 from the cytochrome P450 gene family. Key genes including pik3c2b, pltp, and chia.2 were differentially expressed in both 1 and 0.1 ppm exposures. However, fewer transcriptomic changes were induced by 0.1 ppm compared with 1 ppm. Future studies are needed to determine if these transcriptomic responses during embryogenesis have long-term consequences at levels equal to or lower than 1 ppm.

Odor emissions: A public health concern for health risk perception

The olfactory nuisance, due to the emissions of active molecules, is mainly associated with unproperly managed waste disposal and animal farming. Volatile compounds e.g., aromatics, organic and inorganic sulfide compounds, as well as nitrogen and halogenated compounds are the major contributor to odor pollution generated by waste management plants; the most important source of atmospheric ammonia is produced by livestock farming. Although an odorous compound may represent a nuisance rather than a health risk, long-term exposure to a mixture of volatile compounds may represent a risk for different diseases, including asthma, atopic dermatitis, and neurologic damage. Workers and communities living close to odor-producing facilities result directly exposed to irritant air pollutants through inhalation and for this reason the cumulative health risk assessment is recommended. Health effects are related to the concentration and exposure duration to the odorants, as well as to their irritant potency and/or biotransformation in hazardous metabolites. The health effects of a single chemical are well known, while the interactions between molecules with different functional groups have still to be extensively studied. Odor emissions are often due to airborne pollutants at levels below the established toxicity thresholds. The relationship between odor and toxicity does not always occurs but depends on the specific kind of pollutant involved. Indeed, some toxic agents does not induce odor nuisance while untoxic agents do. Accordingly, the relationship between toxicity and odor nuisance should be always analyzed in detail evaluating on the characteristics of the airborne mixture and the type of the source involved.

Nitrogen-rich layered carbon for adsorption of typical volatile organic compounds and low-temperature thermal regeneration

Carbon-based adsorbents with a high adsorption capacity and low price have been widely used in the removal of volatile organic compounds (VOCs), but the poor gas selectivity and reusability limit their industrial applications. In this work, disc-like nitrogen-rich porous carbon materials (HAT-Xs) were synthesized to remove typical VOCs via adsorption. By controlling the synthesis temperature from 450 to 1000 °C, the C/N ratio of the HAT-Xs increased from 1.85 to 12.56. The HAT-650 synthesized at 650 °C with the high specific surface area of 305 m² g^-1 exhibits the highest adsorption capacity of 141 mg g^-1 for ethyl acetate (which is 3.2 times for that of activated carbon), and 39.4 mg g^-1 for n-hexane, 48.6 mg g^-1 for toluene. Kinetic studies indicated that the adsorption is physical adsorption and that the interior surface diffusion is the main rate-determining step during the adsorption progress, the interior surface diffusion rate of ethyl acetate on HAT-650 is 1.455 mg g^-1 min^-0.5. At the same time, the desorption and reuse tests show that HAT-650 has excellent reusability with low desorption and regeneration temperature of 120 °C, and high desorption efficiency of 95.2% and that it could be a promising ethyl acetate adsorbent for industrial applications.

ACUTE EXPOSURE TO ABUSE-LIKE CONCENTRATIONS OF TOLUENE INDUCES INFLAMMATION IN MOUSE LUNGS AND BRAIN

Toluene is an aromatic hydrocarbon commonly abused by young adolescents for its central nervous system depressant effects. While toluene's pharmacological effects at high concentrations are relatively well known, few studies have assessed toluene's effects on lung and brain tissues. The present study characterized the pathological effects of acute inhaled toluene exposure in the lungs and brains of male Swiss-Webster mice (N = 68). Using a static vapor exposure chamber, mice (PND 28) received a single 30-min toluene administration (0, 1000, 2000, or 4000 ppm). Lung and brain tissues were extracted 24 hrs post-exposure. Histology results revealed significant changes in the morphology lung tissue (e.g., irregular cellular architecture) with the 2000 and 4000 ppm exposures expressing greater signs of pathology than control 0-ppm exposure. Markers of immune system activity (F4/80 and Ly-6G) and cellular proliferation (Ki-67) in the lung revealed no significant differences. Additionally, brain tissues were analyzed for changes of astrogliosis (GFAP) and oxidative stress (GPx). GFAP showed increased astrogliosis in the striatum with 2000 ppm toluene showing significantly higher expression than control (p < 0.05), and a marginal effect in the hippocampus. No other markers showed significant changes. The increased signs of inflammation and cellular damage suggest that exposure to a single high concentration of toluene, typical of abuse, are capable of producing pathology in both lung and brain tissue.

PDMS-coated γCD-MOF solid-phase microextraction fiber for BTEX analysis with boosted performances

Owing to the ubiquitous occurrence and chemotoxicity of BTEX (benzene, toluene, ethylbenzene and xylene), the development of stable and accurate analysis methods that can assess environment risks and can generate monitoring data rapidly is urgent. In this work, a new strategy was proposed for efficient detection of BTEX. By creatively utilizing thermal deposition method, a robust SPME fiber was fabricated, where the γCD-MOF acted as the adsorbent, while PDMS functionalized as the adhesive and protective coating. Benefiting from the protection of PDMS, the γCD-MOF fiber presented significantly better extraction performance and exhibited long-term structural stabilities in aqueous or methanol samples up to a week. The stable and improved properties of γCD-MOF demonstrated that the PDMS protected the MOF components from the adverse effects of solvent. The detection limits of PDMS modified γCD-MOF fiber for BTEX was as low as 0.13-0.29 ng L^-1 that accompanied with wide linear range of 1-1000 ng L^-1, which was significantly superior to commercial PDMS fiber and other MOF-based fibers. Besides, the feasibility of the proposed method was verified by the quantitative determination of BTEX in real water samples. This work presents an effective strategy for creating ultrasensitive and stable SPME fibers based on γCD-MOF for applications in aqueous samples or other poor solvent.

Ethylbenzene exposure disrupts ovarian function in Wistar rats via altering folliculogenesis and steroidogenesis-related markers and activating autophagy and apoptosis

Ethylbenzene is a hydrocarbon that is extensively used in both industry and in the home and has been reported as toxic to various tissues. Nevertheless, its effect on ovarian function remains unclear. For this purpose, we assessed ovarian tissue morphology, evaluated protein and gene expression related to folliculogenesis and steroidogenesis, and investigated the involvement of both apoptosis and autophagy processes in this effect. Female Wistar albinos rats were treated with 2000, 4000 and 8000 ppm doses of ethylbenzene by inhalation for 30 min daily for one month. Ovaries were then removed and proceeded for histopathological and molecular analyses. We found that ethylbenzene affected folliculogenesis by decreasing the number of growing follicles and increasing the number of abnormal follicles, leading to faster female reproductive aging. Interestingly, it disrupted female reproductive hormone balance, including progesterone, estradiol, testosterone and IGF-1 plasma levels. The latter protein, along with GDF-9, significantly decreased in all ethylbenzene-treated groups, leading to the disruption of follicular cell proliferation and development. TUNEL assay study showed that ethylbenzene exposure significantly increased the number of apoptotic cells. The mRNA levels of genes involved in granulosa cell proliferation and differentiation, such as INSL3, CCND2 and ACTB, were significantly decreased. In addition, LC3 protein expression increased, and its encoding gene was upregulated, suggesting that ethylbenzene treatment induced autophagy. In summary, ethylbenzene exposure caused structural and functional disorders of the ovary by disrupting the normal growth of follicles, altering reproductive hormone balance, inhibiting the expression of key reproductive proteins and triggering autophagy as well as apoptosis.

Analysis of 10 Urinary BTEX Metabolites by Liquid Chromatography Tandem Mass Spectrometry

Benzene, toluene, ethylbenzene and xylene (BTEX) are a group of volatile organic compounds that are ubiquitous in the environment due to the numerous anthropogenic sources. Exposure to BTEX pose a health risk by increasing probability for damage to multiple organs, neurocognitive impairment and birth defects. Urinary BTEX metabolites are useful biomarkers for evaluation of BTEX exposure, because of easiness of sampling and their longer physiological half-lives compared with parent compounds. A method that utilizes liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-MS/MS) was developed and validated for simultaneously monitoring ten urinary BTEX metabolites. During the sample preparation an aliquot of urine was diluted by the equal volume of 1% formic acid, internal standards solution was added, then the sample was centrifuged and analyzed. The analytes were separated on the Kinetex-F5 column by applying a linear gradient, consisting of 0.1 % formic acid and methanol. The method was validated according to the FDA Bioanalytical Method Validation Guidance for Industry. The mean method's accuracies of the spiked matrix were 81-122%; the interday precision ranged from 4% to 20%; limits of quantitation were 0.5-2 μg/L. The method was used for evaluation of baseline levels of urinary BTEX metabolites in 87 firefighters.

Estimation of Emission Factors for Hazardous Air Pollutants from Petroleum Refineries

The hazardous air pollutants (HAPs) group is composed of 187 chemicals that are known to be potentially carcinogenic and dangerous for human health. Due to their toxicological impact, HAPs are an increasingly studied class of compounds. Of the different HAPs sources, refineries are one of the major sources. In order to obtain a preliminary assessment of the impact of a refinery in terms of emissions, a useful instrument is the determination of the emission factor (EF). For this reason, this work, focusing on the USA refining scenario, aims to provide evidence for a generic trend in refinery emissions to evaluate a correlation between the plant size and the amount of its emissions, in particular the HAPs emissions. Based on the analysis of the data collected from the U.S. Environmental Protection Agency (US EPA), a general trend in the emissions from refinery plants was established, showing a positive correlation between the HAPs emissions and the refinery size, represented by a value of the Pearson correlation coefficient r close to 1. Once this correlation was highlighted, a purpose of this work became the estimation of an organic HAPs emission factor (EF): from a whole refining plant, the EF of the total organic HAPs is equal to 10 g emitted for each ton of crude oil processed. Moreover, it was also possible to undertake the same evaluation for two specific HAP molecules: benzene and formaldehyde. The benzene and formaldehyde EFs are equal to, respectively, 0.8 g and 0.2 g for each ton of processed crude oil. This work provides a simple rule of thumb for the estimation of hazardous substances emitted from petroleum refineries in their mean operating conditions.