Levels Of Toluene Research Articles

Adsorption dynamics of gaseous toluene with and without formaldehyde and water vapors on composites of UiO-66-NH2 and microporous carbon

To improve the adsorption capacity/selectivity of activated carbon (AC) against diverse volatile organic compounds (VOCs), a series of AC-based composites have been prepared with UiO-66-NH2 (U6N) and coded as AC-U6Nx (x = 1–20 wt/wt%). The adsorption potential of AC-U6Nx is evaluated against toluene in relation to the effects of composite compositions and the presence of competing feed gases/vapors (e.g., formaldehyde (FA) and water vapor). Although AC-U6N(1%) adsorbs toluene preferentially over FA, the selectivity factor of the former decreases from 6.4 to 2.63 as the x value increases from 1 to 20 wt%. This indicates the crucial role of U6N-NH2 groups in active capturing of FA over toluene through Schiff-base adsorption mechanism. Interestingly, the partition coefficient (PC100%: 0.045 ± 0.004 mol kg−1 Pa−1) of AC-U6N(1%) for 100 ppm FA remains nearly constant across varying toluene levels (1–100 ppm), suggesting the preferential occupation of active sites by FA (pore-filling). The contrasting role of relative humidity (RH) is also evidenced, as AC-U6N(1%), exhibits the highest capacity for toluene and FA under dry (0 % RH) and humid (20 % RH) conditions, respectively. The adsorption behavior of VOC on AC-U6N(1%) surface active sites (e.g., graphitic basal planes, NH2, COO–, and Zr sites) is predictable with a good fit of experimental data to the Freundlich isotherm and pseudo-second-order (PSOM) kinetic models. A density functional theory (DFT) simulation supports the enhancement of toluene adsorption on the interface of AC and U6N-based systems. Overall, this work offers practical guidelines for the construction of advanced functional adsorbents against diverse VOCs under both competitive and non-competitive conditions.

Impact of environmental exposures on exhaled breath and lung function: NELA Birth Cohort

Exposure to environmental exposures (i.e.air pollution and second-hand tobacco smoke) have been associated with impaired lung function. However, the impact of environmental factors on lung health is usually evaluated separately and not with an exposomic framework. In this regard, breath analysis could be a non-invasive tool for biomonitoring of global human environmental exposure.Data come from 337 mother–child pairs from the NELA birth cohort. Levels of BTEX (benzene, toluene, ethylbenzene and xylenes) in exhaled breath from mothers and children at 3 months after birth were estimated using gas chromatography-mass spectrometry. Short-term residential exposures (breath sampling day and 15 days before breath sampling) to nitrogen dioxide (NO2), particulate matter (PM2.5), and ozone (O3) were determined by chemical dispersion/transport modelling. Forced vital capacity (FVC), forced expiratory volume at 0.5 s (FEV0.5) and forced expiratory flow at 75% of FVC (FEF75) and at 25%–75% of FVC (FEF25-75) were measured in infants according to the raised-volume rapid thoracoabdominal compression technique.The results showed significant associations between short-term exposure to external agents and levels of benzene and toluene in exhaled breath. It was observed that exhaled levels of benzene and toluene were influenced by smoking status and outdoor air pollution in mothers, and by air pollution in infants (3 months of age). No significant relationship was observed between exposure to maternal tobacco smoking and/or short-term air pollution and lung function in healthy infants. However, there was a significant relationship between FEV0.5and exhaled toluene in children.These findings indicated a significant relationship between environmental exposures and exhaled levels of benzene and toluene, suggesting that breath analysis could be a helpful exposure biomonitoring tool.

GIS-Based Analysis of Volatile Organic Compounds in Bucheon, Korea, Using Mobile Laboratory and Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry Methods.

Recently, volatile organic compounds (VOCs) have been shown to act as precursors of secondary organic particles that react with ultraviolet rays in the atmosphere and contribute to photochemical smog, global warming, odor, and human health risks, highlighting the importance of VOC management. In this study, we measured VOC concentrations in various contexts including industrial and residential areas of Bucheon, Korea, through mobile laboratory and proton-transfer-reaction time-of-flight mass spectrometry methods to determine winter VOC concentrations and visualized the data based on spatial information. Regional characteristics, temperature/humidity, atmospheric conditions, wind speed, traffic volume, etc., during the measurement period of the study site were comprehensively reviewed. For this purpose, global information system (GIS)-based air quality data and various environmental variables were comprehensively reviewed to assess spatial and temporal concentrations in three dimensions rather than in tables and graphs. Among VOCs, the levels of toluene, methanol, and n + i-butene were relatively high, with average concentrations of 48.3 ± 67.2, 34.4 ± 102.7, and 32.6 ± 57.7 ppb, respectively, at the end of the working day. The highest concentrations occurred near the Ojeong Industrial Complex. Mobile pollution sources are also a major driver of VOCs, highlighting the necessity of comprehensively reviewing traffic variables such as road level, estimated traffic volume, and average speed when identifying hotspots of air pollution. GIS-based visualization analysis techniques will improve the efficiency of air quality management.

Association of volatile organic compound levels with chronic obstructive pulmonary diseases in NHANES 2013–2016

Volatile organic compounds (VOCs) represent a significant component of air pollution. However, studies evaluating the impact of VOC exposure on chronic obstructive pulmonary disease (COPD) have predominantly focused on single pollutant models. This study aims to comprehensively assess the relationship between multiple VOC exposures and COPD. A large cross-sectional study was conducted on 4983 participants from the National Health and Nutrition Examination Survey. Four models, including weighted logistic regression, restricted cubic splines (RCS), weighted quantile sum regression (WQS), and the dual-pollution model, were used to explore the association between blood VOC levels and the prevalence of COPD in the U.S. general population. Additionally, six machine learning algorithms were employed to develop a predictive model for COPD risk, with the model’s predictive capacity assessed using the area under the curve (AUC) indices. Elevated blood concentrations of benzene, toluene, ortho-xylene, and para-xylene were significantly associated with the incidence of COPD. RCS analysis further revealed a non-linear and non-monotonic relationship between blood levels of toluene and m-p-xylene with COPD prevalence. WQS regression indicated that different VOCs had varying effects on COPD, with benzene and ortho-xylene having the greatest weights. Among the six models, the Extreme Gradient Boosting (XGBoost) model demonstrated the strongest predictive power, with an AUC value of 0.781. Increased blood concentrations of benzene and toluene are significantly correlated with a higher prevalence of COPD in the U.S. population, demonstrating a non-linear relationship. Exposure to environmental VOCs may represent a new risk factor in the etiology of COPD.

Exposure to Volatile Organic Compounds May Contribute to Atopic Dermatitis in Adults.

Volatile organic compounds (VOC) are major indoor air pollutants. Previous studies reported an association between VOC exposure and allergic diseases. Here, we aimed to explore the relationship between VOC exposure and atopic dermatitis (AD) in adults. We prospectively enrolled 31 adult AD patients and 11 healthy subjects as controls. Urine metabolite levels of VOCs, including 1.3-butadiene, acrylamide, benzene, toluene, and xylene, were all determined with liquid chromatography-mass spectrometry. The relationship between AD and log-transformed urine levels of VOC metabolites were examined using a multivariate linear regression model adjusted for age and sex. We also treated mouse bone marrow-derived cells (BMMCs) with 1,3-butadiene and toluene and measured the release of β-hexosaminidase. Our results demonstrated that creatinine-corrected urine levels of N-Acetyl-S- (3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA), and N-Acetyl-S-(benzyl)-L-cysteine (BMA) were all elevated in AD patients compared with controls. In a multivariate linear regression model, creatinine-corrected urine levels of BMA (a toluene metabolite) and DHBMA (a 1,3-butadiene metabolite) appeared elevated in AD patients, although statistical significance was not reached after correction for multiple comparisons. In addition, 1,3-butadiene and toluene could stimulate BMMCs to degranulate as much as compound 48/80. Some VOCs, such as 1,3-butadiene and toluene, might be associated with AD pathogenesis in adults.

Groundwater Contamination by Gas Stations in Two Eastern Amazonian Towns (Northern Brazil)

The present study analyzed the presence of the principal volatile compounds of the BTEX type (benzene, toluene, ethylbenzene, and xylene [o-, m- and p-xylene]) in samples of water from wells located at residences and gas stations in two Amazonian towns—Tracuateua and Augusto Corrêa—in the Amazon region of northern Brazil. This innovative study is extremely relevant to the Amazonian towns surveyed, given that they lack systematic policies for the environmental control of gas stations and any municipal regulations on the quality of water destined for human consumption. A combination of mass spectrometry (MS) and gas chromatography (CG) techniques was applied to analyze these contaminants in 150 samples of local groundwater collected between 2020 and 2024. One of the four BTEX compounds (toluene) was identified in seven of the samples collected (4.66% of the total) at concentrations of 0.14–2.10 µg L−1. The concentrations of contaminants were low, in general. None of the water samples analyzed here presented any critical loss of water quality for human consumption according to the Brazilian legislation concerning BTEX concentrations. Neither of the two towns surveyed in the present study has remediation programs for environmental contamination. The GC-MS approach produced satisfactory results for the assessment of the contamination of underground water reserves by gas stations in both study towns. Further research (e.g., geophysical methods) will be necessary to determine the source of the contamination and its connection with the levels of toluene identified in the underground water sampled in these Amazonian towns.

Ecological Risk Assessment of Three Pesticide Additives in Soil and Application to the Remediation of Contaminated Soil.

Pesticide additives (PAs) are auxiliary ingredients added to the pesticide manufacturing and use processes, constituting 1% to 99% of the pesticide and often composed of benzene and chlorinated hydrocarbons. We selected three typical PAs, toluene, chloroform, and trichloroethylene, to evaluate their retention function toxicity and ecological risk in soil. Soil immobilization techniques and aquatic model organisms were used to demonstrate the effectiveness of the immobilized soil method to determine the ecological risk of chemicals. The 48-h median lethal concentrations of toluene, chloroform, and trichloroethylene alone in spiked soil on Daphnia magna were 10.5, 2.3, and 1.1 mg/L (medium, high, and high toxicity, respectively). The toxicity of the three-PA mixtures showed an antagonistic effect. The risk levels of toluene, chloroform, and trichloroethylene in the soil were evaluated as moderate to high, low to high, and high risk, respectively. The toxicity of two pesticide-contaminated sites in the Yangtze River Delta before and after remediation was successfully evaluated by immobilized soil technology. The toxicity of two soil sampling points was reduced from medium toxic to low toxic and no toxic, respectively, after remediation. The results of our study give a rationale for and prove the validity of the aquatic model organisms and soil immobilization techniques in assessing the soil retention functions toxicity of PAs. Environ Toxicol Chem 2024;43:1677-1689. © 2024 SETAC.

Association between urinary BTEX metabolites and dyslexic odds among school-aged children.

Benzene, toluene, ethylbenzene, and xylene (BTEX) are ubiquitous in the environment, and all of them can cause neurotoxicity. However, the association between BTEX exposure and dyslexia, a disorder with language network-related regions in left hemisphere affected, remains unclear. We aimed to assess the relationship between BTEX exposure and dyslexic odds among school-aged children. A case-control study, including 355 dyslexics and 390 controls from three cities in China, was conducted. Six BTEX metabolites were measured in theirurine samples. Logistic regression model was used to explore the association between theBTEX metabolites and the dyslexic odds. Urinary trans,trans-muconic acid (MU: a metabolite of benzene) was significantly associated with an increased dyslexic odds [odds ratio (OR) = 1.23, 95% confidence interval (CI): 1.01, 1.50], and the adjusted OR of thedyslexic odds in the third tertile was 1.72 (95% CI: 1.06, 2.77) compared to that in the lowest tertile regarding urinary MU concentration. Furthermore, the association between urinary MU level and thedyslexic odds was more pronounced among children from low-income families based on stratified analyses. Urinary metabolite levels of toluene, ethylbenzene, and xylene were not found to beassociated with the dyslexic odds. In summary, elevated MU concentrations may be associated with an increased dyslexic odds. We should take measures to reduce MU related exposure among children, particularly those with low family income.

BTEX Assessment among Informal Charcoal-Burning Food Traders for Cleaner and Sustainable Environment

This study assessed the cleaner and sustainable environment by measuring emission levels of benzene, toluene, ethylbenzene, and xylene (BTEX) from informal food traders using charcoal as the primary source of energy at a flea market in Fordsburg, Johannesburg. Volatile organic compounds (VOCs) were measured using a real-time monitor (MiniRae 3000 photoionization detector); an indoor air quality (IAQ) monitor was used to monitor environmental parameters and passive samplers in the form of Radiello badges, which were used to determine BTEX emissions from charcoal used during food preparation. Measurements were taken at 1.5 m above ground assuming the receptor’s breathing circumference using PID and Radiello. PID data were downloaded and analyzed using Microsoft Excel(Version 2019). Radiellos were sent to the laboratory to determine the BTEX levels from the total VOCs. The total volatile organic compound (TVOC) concentration over the combustion cycle was 306.7 ± 62.8 ppm. The flaming phase had the highest VOC concentration (547 ± 110.46 ppm), followed by the ignition phase (339.44 ± 40.6 ppm) and coking with the lowest concentration (24.64 ± 14.3). The average BTEX concentration was 15.7 ± 5.9 µg/m3 corresponding to the entire combustion cycle. BTEX concentrations were highest at the flaming phase (23.6 µg/m3) followed by the ignition (13.4 µg/m3) and coking phase (9.45 µg/m3). Ignition phase versus the flaming phase, there was a significant difference at 95% at a p-value of 0.09; ignition phase versus the coking phase, there was a significant difference at 95% at a p-value of 0.039; and coking phase versus the flaming phase, there was a significant difference at 95% at a p-value of 0.025. When compared to the occupational exposure limits (OELs), none of the exposure concentrations (BTEX) were above the 8 h exposure limit. The findings of this study suggest that charcoal, as a source of energy, can still be a useful and sustainable fuel for informal food traders. Shortening the ignition and flaming phase duration by using a fan to supply sufficient air can further reduce exposure to VOCs.

Analysis of Heavy Metals and Petroleum Based Contaminants in Surface Water and Sediment near two Illegal Refining Sites in Niger Delta, Nigeria

The pollution of the environment from heavy metals and petroleum based contaminants in surface water and sediments resulting from illegal refining activities were looked at. The study was aimed at assessing the levels of heavy metals (Pb, Zn, Cu, Co, Cr, As, Cd and Ni), Benzene, Toluene, Ethyl-Benzene, and Xylene (BETX), Polycyclic Aromatic Hydrocarbons (PAHs) and Total Hydrocarbon Content (THC) in surface water and sediments. Samples were collected from two deactivated sites of illegal refineries in Oshika and Egbalor communities of Rivers State, Nigeria. The samples were analyzed for the contaminants which were compared with the World Health Organization (WHO) standard. The findings indicate that the surface water and sediments were highly polluted and may pose a health hazard to the community members that may use it for drinking.

Assessment of volatile organic compounds in indoor and outdoor environment – A study on air quality impact assessment

Objectives: Volatile organic compounds (VOCs) are a type of pollutant that causes health risks and can be present in both indoor and outdoor environments. VOCs originate mainly from solvents and chemicals used at home or in offices and also from vehicle emissions. The current research work was aimed at the detection and quantification of VOCs indoor and outdoor at Sri Ramachandra Faculty of Pharmacy, Sri Ramachandra Institute of Higher Education and Research (DU), Porur, Chennai, Tamil Nadu, India. Material and Methods: Air was drawn through an adsorbent tube with a pump at a steady flow rate (100 mL min-1) for an hour to gather samples using the active sampling approach. Thermal desorption in combination with a gas chromatography (GC) analyzer was used to estimate the levels of hazardous VOCs, namely benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene (BTEX) compounds. Results: VOCs were analyzed using the GC-mass spectroscopy technique. The finding shows the levels of BTEX as benzene (0.05–0.11 μg/m3), toluene (0.44–1.27 μg/m3), ethylbenzene (0.012–0.03 μg/m3), m-xylene (0.009–0.027 μg/m3), p-xylene (0.007–0.025 μg/m3), and o-xylene (0.003–0.019 μg/m3) compounds. Conclusion: The BTEX levels were observed to be well below the maximum acceptable limit. VOC emissions can be reduced by making process changes or by installing air pollution control equipment.

Volatile Metabolite Profiles of Robusta Green Bean Coffee From Different Geographical Origins in West Java and Their Correlation With Temperature, Rainfall, and Altitudes Using SPME GC‐MS–Based Metabolomics

The chemical composition, including volatile metabolites of green coffee beans, is influenced by geographic origin. The aim of this study was to reveal the volatile metabolite profile of a single variety of Robusta green bean coffee from five major plantation regions in West Java and to correlate these profiles with temperature, rainfall, and altitude. By using solid phase micro extractions and gas chromatography‐mass spectrometry, 143 different volatile compounds were detected, with aromatic hydrocarbon, alcohols, monoterpene, pyrazines, sesquiterpenes, carboxylic acids, and terpene the most dominant. Principal component analysis (PCA) indicated 64.3% variability, showing that the metabolite profile of Robusta green coffee from the Bogor region was distinctly different from those in Ciamis, Kuningan, Sumedang, and Tasikmalaya, which were more similar to each other. Metabolites such as benzaldehyde, isovaleric acid, toluene, diisobutyl succinate, 1‐heptene, 4‐dodecene, caffeine, acetic acid, and methyl benzoate were identified as key discriminants, with a VIP score greater than 1.5. Temperature increases were linked to higher levels of isovaleric acid, diisobutyl succinate, 4‐dodecene, toluene, and acetic acid, while other discriminant metabolites declined. Increased rainfall was associated with higher levels of benzaldehyde, 1‐heptene, caffeine, and methyl benzoate, but lower levels of the other discriminants. Altitude had a positive correlation with methyl benzoate and 1‐heptene, and a negative correlation with isovaleric acid and 4‐dodecene, with weaker correlations for other compounds. In summary, Robusta green coffee beans from different regions of West Java can be distinguished by their volatile metabolites. Bogor green coffee beans had higher levels of benzaldehyde, 1‐heptene, caffeine, and methyl benzoate, Kuningan beans had more diisobutyl succinate and 4‐dodecene, Ciamis beans had higher levels of isovaleric acid, diisobutyl succinate, and 4‐dodecene, while Sumedang and Tasikmalaya beans were similar, with higher levels of isovaleric acid, diisobutyl succinate, 4‐dodecene, toluene, and acetic acid. This difference is related to the climatic factors of temperature and rainfall, as well as the altitude at which Robusta coffee is grown.

Laboratory evaluation of a prototype portable gas chromatograph (GC) with a flame ionization detector (FID) for toluene, ethylbenzene, and xylenes (TEX) analysis

The standard method to evaluate human exposure to volatile organic compounds (VOCs) is in general performed by sampling the air on sorbents followed by liquid extraction and detection using laboratory gas chromatograph (GC). The conventional method is time and labor intensive and employs a toxic solvent which adds a risk factor as well as waste. Hence, there have been increasing demands for portable GC instruments which allow near real-time, in-situ analysis. In this study, the potential use of a prototype, dual column portable GC (protoGC) with flame ionization detector (FID) was examined by comparing its performance with a conventional GC laboratory method. Four target concentration levels (1x, 2x, 4x, and 8x; x = 1.12 ± 0.01 ppm) of toluene, ethylbenzene, and o-, m-, and p-xylene were generated in an exposure chamber (24 ± 1 °C and 50 ± 5% RH). The challenge atmosphere was directly sampled and analyzed with protoGC while for the conventional method it was sampled on a sorbent tube and analyzed with a laboratory GC/FID. The results of protoGC correlated well with the conventional method (r = 0.991–0.999), indicating that protoGC has comparable performance with the conventional method within the test conditions. Although two-way ANOVA showed significant differences in mean concentrations between the methods, the differences were small. protoGC would be useful to monitor VOCs in air with high temporal resolution or to quickly determine the safety of the environment of interest due to the substantial time savings in sampling and analysis. Further examinations at various environmental conditions and other analytes will be necessary to thoroughly evaluate its performance.

Influence of Environmental Exposure to Steel Waste on Endocrine Dysregulation and PER3 Gene Polymorphisms.

To evaluate the association between environmental exposure to the following chemical substances: cadmium (Cd), lead (Pb), nickel (Ni), manganese (Mn), benzene (BZN), and toluene (TLN), and Period Circadian Regulator 3 (PER3) gene variable number of tandem repeats (VNTR) polymorphisms, according to chronotype in a population living in a steel residue-contaminated area. This assessment comprises a study conducted from 2017 to 2019 with 159 participants who completed health, work, and Pittsburgh sleep scale questionnaires. Cd, Pb, Ni, Mn, BZN, and TLN concentrations in blood and urine were determined by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) and Headspace Gas Chromatography (GC), and genotyping was carried out using Polymerase Chain Reaction (PCR). A total of 47% of the participants were afternoon chronotype, 42% were indifferent, and 11% were morning chronotype. Insomnia and excessive sleepiness were associated with the indifferent chronotype, while higher urinary manganese levels were associated with the morning chronotype (Kruskal-Wallis chi-square = 9.16; p < 0.01). In turn, the evening chronotype was associated with poorer sleep quality, higher lead levels in blood, and BZN and TLN levels in urine (χ2 = 11.20; p < 0.01) in non-occupationally exposed individuals (χ2 = 6.98; p < 0.01) as well as the highest BZN (χ2 = 9.66; p < 0.01) and TLN (χ2 = 5.71; p < 0.01) levels detected in residents from the influence zone 2 (far from the slag). Mn, Pb, benzene, and toluene contaminants may have influenced the different chronotypes found in the steel residue-exposed population.

Health risk assessment of BTEX exposure at roadside and on-road traveling route in Bangkok Metropolitan Region

Exposure to high levels of benzene, toluene, ethylbenzene, and xylenes (BTEX) poses health risks in high-traffic urban areas. BTEX exposure at two microenvironments, the roadside and along the traveling routes, within urban and suburban areas of the Bangkok Metropolitan Region was examined to assess cancer and noncancer risks. The lifetime cancer risk (LCR) for benzene and noncancer hazard index (HI) for all BTEX compounds were evaluated for adult male and female groups (drivers, passengers, and street vendors) in two scenarios: average case and worst case. With the assumption of negligible exposure outside the two considered microenvironments, the pickup drivers had the highest LCR and HI. Higher exposure risks were found in urban areas than in the suburbs and among men than females. Higher toluene levels were found at all monitoring sites in two microenvironments, but benzene was the most important in causing noncancer risk. The HI for all target groups ranged from 8.5E-03 to 4.0E-01, indicating a low noncancer risk from BTEX exposure (HI &lt; 1). The LCR caused by benzene exposure ranged from 1.7E-06 to 7.2E-05, which is higher than the United States EPA most health-protective limit (1E-06). Further research should include other microenvironments by assessing the 24-hour exposure of all considered groups.

Evaluation of environmental and biological monitoring methods for toluene exposure assessment in paint industry

The aim of this study was to assess the exposure to Toluene in paint industry and to evaluate the environmental and biological monitoring techniques for the assessment of occupational exposure to this aromatic hydrocarbon. In this study, personal active and passive air sampling for toluene measurements, blood and urine sampling respectively for B-Tol and HA or U-Tol analyses for eight workers from two paint and thinner production factories were collected during four successive working days. Correlations were analyzed between biological indicators and environmental toluene exposure levels.The concentration of Toluene measured in air samples ranged from 0.2 to 414.0 ppm (mean = 59.8 ppm), with high variability of atmospheric levels between activities and between days. No significant difference was found between airborne toluene concentrations measured by the two sampling methods. The correlation between air concentrations sampled by the diffusive sampling method and the biomarkers was the best for HA (r = 0.902, p < 0.01), followed by B-Tol (r = 0.820; p < 0.01), o-Cr (r = 0.691; p < 0.01) and U-Tol (r = 0.607; p < 0.05). The correlation was better between air concentrations and urinary metabolites HA and o-Cr for exposure levels higher than 50 ppm (r = 0.931; p < 0.01), and lower than 300 ppm (r = 0.827; p < 0.01), respectively.According to our results, workers in the studied industries are highly exposed to Toluene. Given the high correlation found between toluene concentrations in samples taken on dosimeters and those actively sampled on charcoal tubes, it may be assumed that both sampling methods are valuable. Despite the influencing factors, HA was found to be a reliable biological indicator for the monitoring of occupational exposure to toluene for high exposure levels. However, B-Tol seems to be an interesting alternative, since it is more specific and showed the best correlations with airborne toluene levels.

Exposure to volatile organic compounds and risk perception among workers: An industry-based cross-sectional survey

This study aimed to determine the volatile organic compound (VOC) exposure levels and evaluate the risk perception among integrated circuit assembly and testing workers in Taiwan. Five representative companies were selected as the study population to measure the VOC levels of benzene, toluene, ethanol, acetone, and isopropyl alcohol using 50 stainless steel canisters in 2013. A gas chromatograph with a flame ionization detector was used to analyze the VOC levels, and multiple logistic regression models were used to identify relative factors of risk perception among 210 volunteers using a self-administered questionnaire. Ethanol (median: 465.1 ppbv; range: 64.8–1744.3 ppbv) had the highest concentration compared with isopropyl alcohol (291.6 [171.8–411.4] ppbv), acetone (176.3 [106.8–528.4] ppbv), toluene (171.6 [130.2–240.1] ppbv), and benzene (all below the limit of detection of 6.95 ppbv). Subjects exposed to the total of five VOCs ≥406.5 ppbv had a significantly higher risk perception of health hazards caused by hazardous gas exposure (AOR = 4.17, 95% CI = 1.17–14.93) compared with those exposed to <278.1 ppbv. A significant exposure–response association was identified in the total levels of the five VOCs and risk perception (AOR = 2.03, 95% CI = 1.07–3.85). Workers exposed to higher levels of the total of five VOCs may have higher risk perceptions.

Measurement of indoor and outdoor SO2 and NO2 and indoor BTEX/VOC concentrations at pre-schools in Mabopane Township, Tshwane Metropolitan Municipality, Gauteng Province, South Africa

Introduction: Children spend approximately 7 hours a day at pre-schools, mostly indoors. The aim of the study was to assess indoor and outdoor SO2 and NO2 and indoor BTEX/VOC at pre-schools situated in Mabopane, Tshwane Metropolitan Municipality, Gauteng Province, South Africa Methodology: Six pre-schools in the study area were purposively selected to participate in the study. Indoor and outdoor levels of SO2 and NO2, and indoor BTEX/VOC were assessed over 24hrs for two weeks using Radiello passive samplers. Indoor temperature and relative humidity were also monitored using temperature data loggers. The outdoor temperature and relative humidity data was provided by South African Weather Services. Results: The indoor and outdoor SO2 median levels were 0.22 &amp;#x3bc;g.m-3 and 1.12 &amp;#x3bc;g.m-3 The indoor and outdoor NO2 median levels were 21.10 &amp;#x3bc;g.m-3 and 17.22 &amp;#x3bc;g.m-3, respectively. The indoor/outdoor ratios for NO2 and SO2 were 0.20 and 1.07, respectively. The infiltration factor parameter estimates of NO2 and SO2 were 0.48 and 0.01. The indoor and outdoor temperature and relative humidity levels were 2.11 &amp;#xb0;C and 22.4 &amp;#xb0;C, and 43.14% and 57%. The median concentrations of BTEX ranged from 0.5µg/m3 to 43.19µg/m3. The Kruskal-Wallis test showed that the level of benzene in the six schools differed significantly - χ^2=13.87,p-value=0.016. The levels of toluene at the six school did not differ significantly - χ^2=5.96,p-value=0.310. There was no statistically significant difference between the six schools in terms of ethylbenzene - χ^2=6.30,p-value=0.2710. The p-value for Xylene showed there was no statistically significant difference between the six schools - χ^2=6.01,p-value=0.2967.. Conclusion: The levels of outdoor NO2, SO2 and BTEX/VOC were below the South African National Ambient Air Quality Standards and WHO Air Quality Guidelines. However, they still pose a health risk for children attending pre-school in the area. Keywords: Air pollution; SO2, NO2, BTEX/VOC, Temperature; Relative humidity; South African

Source identification, spatial distribution and ozone formation potential of benzene, toluene, ethylbenzene, and xylene (BTEX) emissions in Zarand, an industrial city of southeastern Iran

Introduction: Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) as the ozone precursors have been classified as the hazardous air pollutants because of their negative effects on humans. This article presents the results of the first assessment of source identification, spatial distribution and BTEX's Ozone- Forming Potential (OFP) in Zarand.&#x0D; Materials and methods: The current study was conducted at 30 geographically separated locations, in Zarand, Kerman, southeastern Iran, during the summer and winter of 2020. BTEX samples were collected using passive samplers and then analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Spatial variations were surveyed using the Kriging method in GIS.&#x0D; Results: Total BTEX levels (79.26±26.87 µg/m3) during the summer were greater than their levels in the winter (37.38±29.18 µg/m3). The ranking of BTEX level in all samples followed as: toluene&gt;m,p-xylene&gt;o- xylene&gt;ethylbenzene&gt;benzene. The overall OFP of 374.79±135.08 µg/m3 in the summer and 172.61±148.81 µg/m3 in the winter were more than 100 µg/m3 as recommended guideline defined by World Health Organization (WHO), with toluene having the highest potential.&#x0D; Conclusion: According to the results of the present study, BTEX relative abundances in all samples were toluene&gt;m,p-xylene&gt;o- xylene&gt;ethylbenzene&gt;benzene. Despite of concerns among inhabitants and workers, benzene concentration was lower than other studied species. Control measures such as management of fuel use in motor vehicles and industries and development of green space must be adopted to attenuate the level of toluene in the atmosphere in the studied area.

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.