Average Concentrations Of Toluene Research Articles

An Indoor Air Quality Analysis in Newly Constructed Apartments

This study analyzes the indoor air quality inspections of newly constructed apartments by the Busan Institute of Health and Environment for the last three years (2021-2023). Of the 41 inspections, 33 exceeded the recommended standard, and the average excess rate was 80.5%. When classified by measuring households, 148 out of 332 exceeded the standards, whereas, the average excess rate by household was 44.6%. Benzene was exceeded in two out of the 332 households; therefore, the excess rate was only 0.6%. However, the relative standard deviation was the largest, showing as the highest item in the scattergram. The average concentration of toluene was 1,006.0 µg/m3, which was 100.6% of the recommended standard and was exceeded by 138 households; hence, the excess rate was 41.6%. All six items(Formaldehyde, Benzene, Toluene, Ethylbenzene, Xylene, Styrene) reached the highest concentration in spring or summer when the indoor temperature increased. The average concentration of toluene in July was 1,922 µg/m3, close to 1.9 times the recommended standard; toluene is considered an item of particular concern in summer. In the correlation analysis with indoor temperature, the formaldehyde coefficient of determination was 0.4855, regarded as somewhat significant; it was difficult to confirm the correlation with temperature for the other five items, including benzene. In correlation with relative humidity, formaldehyde showed the same tendency as indoor temperature, with a coefficient of determination of 0.4404, which is believed to be due to its small molecular weight and high solubility. Due to the chimney effect, high concentrations of volatile organic compounds could be confirmed at low atmospheric pressure in the upper floors, and this trend was most evident for formaldehyde. For most items(Formaldehyde, Benzene, Toluene, Ethylbenzene, Styrene), a negative correlation was confirmed in which the emission amount decreased as the number of households increased. For large apartment houses, it is believed that it is due to sufficient bake-out and flush-out according to the adequate construction period and the use of eco-friendly and high-end building materials. Small apartments are classified together with many small houses. The emission concentration of small houses is relatively high because the proportion of the surface area where pollutants are released is high.

Mathematical description of birch bark impregnation and heating process of birch bark with toluene

On the basis of differential equations of heat and mass conductivity and given boundary conditions the mathematical model describing the process of heating and birch bark impregnation with an extractant was developed. Experimental facilities for impregnation and determination of mass conductivity coefficient are created. Kinetic dependence of average concentration of toluene in birch bark during impregnation is obtained. The temperature dependence of toluene mass conductivity coefficient through birch bark was obtained on the setup for determination of mass conductivity. The analysis of kinetic curves of birch bark impregnation with toluene at different temperatures shows a considerable influence of temperature on the impregnation rate. The discrepancy between the calculated and experimental data does not exceed 13%. The rational temperature of impregnation, which is 110 °С, has been determined. Optimum time of birch bark impregnation -10 minutes -has been determined. Developed mathematical model of the process of impregnation and heating of wood particles can be applied to organization of calculations of the process of extraction of biologically active substances from vegetable raw materials.

Relationship between Toluene Concentration, Malondialdehyde (MDA) Level and Health Complaints in Workers of Surabaya Printing Industry

Introduction: Toluene is one of the chemical compounds used in the production process in the printingindustry. Exposure toluene that exceeds the threshold value continuously can result in increased levels ofmalondialdehyde and the possibility of experiencing various health complaints. The purpose of this studywas to determine the relationship between toluene concentrations, malondialdehyde levels and healthcomplaints in workers at X Surabaya printing.Methods: This research is observational with quantitative approach and cross sectional design. The studywas conducted on workers in X Surabaya printing. The number of respondents in this study were 19 people.The variables studied were toluene concentration, malondialdehyde levels, and health complaints. Data wereanalyzed using Pearson correlation test.Result: The average concentration of toluene was 1.2311 ppm and the average concentration ofmalondialdehyde was 8,323 MU. Pearson correlation test results showed the relationship of tolueneconcentration with malondialdehyde obtained p value = 0.508 (p> 0.05). While the results of healthcomplaints that were most experienced were coughing (74%), headaches (63%) and shortness of breath(26%).Conclusion: There is no significant relationship between toluene concentration and malondialdehyde level.While the most commonly experienced health complaints are coughing, headaches, and shortness of breath.

Spatial Distribution of BTEX and Inorganic Pollutants During Summer Season in Yalova, Turkey

Abstract The objective of this research is to determine the atmospheric concentrations and spatial distribution of benzene (B), toluene (T), ethylbenzene (E) and xylenes (X) (BTEX) and inorganic air pollutants (O3, NO2 and SO2) in the Yalova atmosphere during summer 2015. In this study, a combination of passive sampling and Geographical Information System-based geo-statistics are used with spatial statistics of autocorrelation to characterise the spatial pattern of the quality of air based on concentrations of these pollutants in Yalova. The spatial temporal variations of pollutants in the air with five types of land-use, residence, rural, highway, side road and industrial areas were investigated at 40 stations in Yalova between 7th August 2015 and 26th August 2015 using passive sampling. An inverse distance weighting interpolation technique was used to estimate variables at an unmeasured location from observed values at nearby locations. The spatial autocorrelation of air pollutants in the city was investigated using the statistical methods of Moran’s I in addition to the Getis Ord Gi. During the summer, highway and industrial sites had higher levels of BTEX then rural areas. The average concentration of toluene was measured to be 5.83 μg/m3 and this is the highest pollutant concentration. Average concentrations of NO2, O3 and SO2 are 35.64, 84.23 and 3.95 μg/m3, respectively. According to the global results of Moran’s I; NO2 and BTEX had positive correlations on a global space at a significant rate. Moreover, the autocorrelation analysis on the local space demonstrated significant hot spots on industrial sites and along the main roads.

Assessment of Surface Water Contamination from Coalbed Methane Fracturing-Derived Volatile Contaminants in Sullivan County, Indiana, USA.

There is a growing concern over the contamination of surface water and the associated environmental and public health consequences from the recent proliferation of hydraulic fracturing in the USA. Petroleum hydrocarbon-derived contaminants of concern [benzene, toluene, ethylbenzene, and xylenes (BTEX)] and various dissolved cations and anions were spatially determined in surface waters around 15 coalbed methane fracking wells in Sullivan County, IN, USA. At least one BTEXcompound was detected in 69% of sampling sites (n = 13) and 23% of sampling sites were found to be contaminated with all of the BTEXcompounds. Toluene was the most common BTEX compound detected across all samplingsites, both upstream and downstream from coalbed methane fracking wells. The average concentration of toluene at a reservoir and its outlet nearby the fracking wells was ~2× higher than other downstream sites. However, one of the upstream sites was found to be contaminated with BTEX at similar concentrations as in a reservoir site nearby the fracking well. Calcium (~60ppm) and sulfates (~175ppm) were the dominant cations and anions, respectively, in surface water around the fracking sites. This study represents the first report of BTEX contamination in surface water from coalbed methane hydraulic fracturing wells.

BTEX Emissions from the Largest Landfill in Operation in Rio de Janeiro, Brazil.

The emission rates and the ambient air concentrations of benzene, toluene, ethyl benzene and xylenes (BTEX) were measured over the intermediate cover layer and atmosphere of the Seropédica landfill, Rio de Janeiro, Brazil. BTEX were sampled using coconut shell charcoal cartridges, followed by extraction with dichloromethane and analysis by gas chromatography with mass spectrometry. Thirteen samples were collected in areas with and without cracks in the cover layer, and six samples were collected from the ambient air. The average emission rates were 11.7, 492.2, 153.7, 67.2, and 21.7µg m- 2 day- 1, respectively, for benzene, toluene, ethyl benzene, m + p-xylenes and o-xylene. No benzene concentrations above the detection limit were observed in ambient air samples. The average concentrations of toluene, ethyl benzene, m + p-xylenes and o-xylene in ambient air samples were 2.14, 1.35, 0.49 and 0.08µg m- 3, respectively. Higher emissions were found in locations containing larger cracks during the collection.

소규모 세탁소의 휘발성유기화합물 발생 특성과 종사자의 건강에 미치는 영향

Objectives: The objective of this study was to evaluate the generating characteristics of VOCs and the exposure effect to chemicals among laundry workers and to identify the current status of occupational safety and health through health check-ups. Methods: During the six-month period from April to September 2015, this study quantitatively measured seven VOCs in ten laundries and carried out health examinations on 35 workers. Results: Comparing the monitoring results for the ten laundries, they were classified into three groups by ventilation system, dry-cleaning and size of shop. The average concentration of toluene, chlorobenzene, xylene, ethylbenzene, benzene, styrene and TCE were 23.9, 15.6, 5.5, 2.8, 0.9, 0.3 and , respectively. During dry-cleaning, VOC concentrations were 1.3-8.9 times higher than usual. On the other hand, at night the concentrations of toluene, chlorobenzene, xylene, ethylbenzene, benzene, styrene and TCE were 64.3, 41.5, 12.2, 6.3, 1.1, 1.2 and , respectively. The health checkup results for the 35 workers showed that 13 workers were diagnosed as normal, while 22 workers were diagnosed as requiring continuous monitoring or re-checkup of liver and hematogenous functions. Conclusions: Although the results of exposure evaluation to VOCs did not exceed reference value and items had a low correlation with health checkup items, it is necessary to improve indoor air quality due to VOC volatilization from clothes.

Neuropsychological Symptoms among Workers Exposed to Toluene and Xylene in Two Paint Manufacturing Factories in Eastern Thailand.

The study analyzed the exposure factors that may lead to neuropsychological symptoms among 92 workers who were exposed to xylene and toluene and 100 workers who were not exposed to the solvents. The airborne concentration of xylene and toluene was evaluated with personal passive badges. The levels of methyl hippuric acid and hippuric acid in urine were assessed, and interviews were performed to observe the neuropsychological symptoms that may result from exposure to the solvents. The result showed that the average concentration for the exposed group of xylene in the paint company working environment was 2.7 (SD = 2.4) ppm and the average concentration of toluene was 9.5 (SD = 10.4) ppm. The average level of methyl hippuric acid in urine was 78 (SD = 74.7) mg/g creatinine. Factors that affected the neuropsychological symptoms included the following. (1) The impact of age: the risk (adjusted odds ratio) for getting psychosomatic symptoms in persons over 40 and exposed to xylene was 9.5 and the aOR of those exposed to toluene was 8.3. (2) The impact of not providing personal protective equipment was found to be sleep disturbance; it was found that the aOR of those exposed to xylene was 3.9, and the aOR of those exposed to toluene was 4.4. In summary, periodic examination of workers by occupational physician is needed for detection of early neuropsychological effects, especially psychosomatic symptoms, and sleep disturbances.

Monitoring of benzene, toluene, ethyl benzene, and xylene isomers emission from Shahreza gas stations in 2013

Aims: The aims of this study were to monitor the concentration of benzene, toluene, ethyl benzene and xylenes (BTEX) in the ambient air of the city of Shahreza gas stations and to identify the spreading distance of the pollutants from the fueling stations. Materials and Methods: Sampling was carried out from the air of 10 existing fuel stations, (2 compressed natural gas and 8 gasoline and diesel stations) and points of 50, 150 and 250 m away from the stations during cold and warm seasons in 2013. Air samples were taken via active sampling process using activated carbon tubes, extracted by carbon disulfide and analyzed by a gas chromatograph coupled to a flame ionization detector. Results: The averages of all achieved BTEX concentrations were under/around the permitted guideline levels for occupational exposure. According to the ambient air guidelines, the benzene level was much higher than the suggested levels in all the stations. However, the average concentrations of toluene, ethyl benzene, and xylene were not exceeded from the standards. The seasonal variation had no influence on the concentrations of BTEX. There was no significant difference between the pollutants concentrations at points 50, 150 and 250 m away from the stations. Conclusions: Fuel stations could be the main sources of volatile organic compounds emission in the city of Shahreza. The number and volume of refueling in the gas stations influence the emission rates. Therefore, it is suggested to take preventive actions such as repairing of pumps and tanks leak and installing vapor return systems at the time of fuel transferring.

Effects of vehicle ventilation system, fuel type, and in-cabin smoking on the concentration of toluene and ethylbenzene in Pride cars

Aims: This study aimed to evaluate the concentrations of toluene and ethylbenzene inside the Pride cars and to investigate the effects of the vehicle ventilation system, fule type, and interior smoking on their concentration. Materials and Methods: In the present study, 152 different models of Pride cars, stopped in parking [classified into three groups including: Pride KIA (Group I), Saba (Group II) 131, 141, 132, LX111, SX, and Nasim (Group III)] were sampled using activated carbon sorbent tube. The samples were analyzed using gas chromatograph-mass spectrometer. The vehicle ventilation, fuel type, and in-cabin smoking were recorded. Results: The average concentrations of toluene and ethylbenzene were 105.4 ± 270.5 and 19.09 ± 33.97 μg/m 3 , respectively. The average concentration of toluene was higher than that of ethylbenzene. The concentration differences of both toluene and ethylbenzen among the studied groups were not statistically significant.Conclusion: The ventilation condition, fuel type, and in-cabin smoking were not significantly impressive on the toluene and ethylbenzene concentrations inside the cars. However, simultaneous usage of the vehicle ventilation system and natural ventilation (windows) could lead to little decrease in toluene concentration levels inside the car, while smoking consumption by passengers can increase them.

VOLATILE ORGANIC COMPOUNDS MEASUREMENT IN THE BOUNDARY OF WASTE TREATMENT FACILITIES

Concentrations of the principal volatile organic compounds, such as benzene, toluene, ethylbenzene, m,p,o-xylene, styrene, and chlorobenzene were measured at the solid waste treatment plants classified into four categories; municipal waste incinerator, municipal waste landfill site, industrial waste incinerator and industrial waste landfill site. The average concentration of VOCs in industrial waste treatment facilities was 33.43 ppb and was significantly higher than that measured at municipal waste treatment facilities (4.71 ppb). The average toluene concentrations measured at incinerators (13.05 ppb) were a little higher than those measured at landfill sites (11.54 ppb). The contribution of the waste treatment facilities to the concentration of benzene (0.35 ppb) and o-xylene (0.15 ppb) in the industrial area was relatively small. However, toluene measured in the industrial waste treatment facilities was the most abundant VOCs with the average concentration of 21.37 ppb. As a result of analyses of fingerprint, in cases of IISH and ILUS, a variety of compounds other than major VOCs were detected in high level. On the Pearson correlation analysis, the correlation was generally positive and some pairs of these VOCs were very strongly correlated (correlation coefficient > 0.75).

Exposure and Health Risk Assessment of Volatile Organic Compounds on Residents Adjunctive With the Central Industrial Park

MM4-PD-07 Introduction: The aims of this study were to investigate the exposure to volatile organic compounds (VOCs) and to perform health risk assessment on residents adjunctive with central industrial park. Methods: Four roads linked to outsides of this park were selected as 5 sites to measure the volatile organic compounds emitted from the traffic. Area with the estimated maximum concentration by ISC-ST 3 model and adjunctive communities within 3 km of this park were determined as 5 eligible places to conduct the environmental sampling. Sampling and analysis method followed TO-14 adopted by the U.S. Environmental Agency. We performed 12-hour air sampling by using 10 canisters seasonally. These samples were subject to qualitative and quantitative analyses by using the GC/MS. The chronic hazard index (HIc) and the cancer risk were used to assess the noncarcinogenic and carcinogenic risks of volatile organic compounds for residents. Results: We found the average concentration of total VOCs increased from 127 ± 68 ppb in spring to 163 ± 146 ppb in autumn but decreased with 49 ± 28 ppb in winter dramatically. VOCs related to industry emission, such as acetone, 2-butanone, ethanol, and isopropyl alcohol, had the raising concentration observably from spring to autumn but reduced in winter. In contrast, only the average concentration of toluene had the obvious increment compared with other traffic-related VOCs during the study period. We estimated that residents adjunctive with the central industrial park had the HIc between 0.004 to 0.014 from exposure to benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, and styrene. Cancer risks of these residents were estimated at 1.3 × 10−6 to 5.8 × 10−6 by exposing to benzene. Discussion and Conclusions: Residents adjunctive with the central industrial park have the acceptable noncancer risk (HIc <1) due to chronic exposures to VOCs but have the estimated cancer risk above the acceptable level (1 × 10−6). We suggest that more precise exposure assessment and prolonged monitor should be conducted to evaluate residents’ potential cancer risk in the future.

Multicenter field trial on possible health effects of toluene: I. Toluene body burdens in workers of the rotogravure industry

Ambient air toluene concentrations as well as corresponding individual blood toluene levels were measured under conditions of a field trial, as basis for a correlation with possible acute effects. While the results of various psycho-physiological and medical evaluations after acute (Neubert et al., 2001) and long-term toluene exposure (Gericke et al., 2001) are published in accompanying papers, this publication deals with the exposure levels and body burdens characteristic of workers in the rotogravure industry in Germany at the time of the investigation (1993–1995). Besides providing some information on the exposure at various work-areas under occupational conditions, the correlation between a time-weighted average of the ambient air concentration with the corresponding blood toluene levels is analyzed. Limitations of such an attempt and possible pitfalls are discussed. In the largest field study so far performed on toluene exposure, 12 companies of the German rotogravure industry (and a total of 1528 volunteers) participated. Altogether, complete data sets, i.e. on both ambient air as well as blood toluene levels, were obtained from 1244 male and 124 female participants of the rotogravure industry with quite different degrees of toluene exposure. Rotogravure printers and their helpers were exposed to the highest toluene concentrations in ambient air. On the day of the evaluation, of 806 male volunteers within this group (of 1261 with verified exposure in air), 35 were exposed to a time-weighted average of 100 ppm (i.e. 375 mg/m 3) or above, and 155 of the printers to concentrations between 50 and 100 ppm. Of the remaining 455 male participants of the rotogravure factories (‘non-printers and helpers’), only three were exposed to toluene concentrations above 50 ppm. Only one of the 124 women working in the rotogravure factories was exposed to an average toluene concentrations above 100 mg/m 3 (i.e. 27 ppm). In 66 of the male volunteers toluene levels in blood of >850 μg/l were measured and 14 showed levels exceeding 1700 μg/l. When attempting to predict the resulting individual blood toluene levels from measurements of ambient air concentrations under field conditions, a considerable uncertainty is to be expected. We found a correlation coefficient of the regression curve of about 0.70, with numerous outliers (and a variation of the 12 factories between 0.52 and 0.88).

Occupational chronic exposure to organic solvents. XVI. Ambient and biological monitoring of workers exposed to toluene.

Ambient air and biological monitoring of an occupational toluene exposure was carried out on a group of 33 workers. The biological monitoring of the workers was based on determination of the concentration of toluene in blood and on quantification of the urinary metabolites o-cresol and hippuric acid. All blood and urine samples were collected post-shift. The average toluene concentration in the workplace air was 65 ppm, ranging from 13 to 151 ppm. AN average concentration of toluene in the blood of 911 microns/1 was found, corresponding to an average urinary concentration of 2.9 mg/1 (2.3 mg/g creatinine) o-cresol and 2.4 g/l (1.9 g/g creatinine) hippuric acid. Both urinary metabolites can be correlated with the concentration of toluene in ambient air and blood, respectively. The results of our study indicate that the determination of the urinary o-cresol excretion represents a diagnostically specific and sensitive parameter for the estimation of an individual toluene uptake. In contrast, monitoring of the concentration of hippuric acid in urine cannot be recommended for assessment of individual exposure. To set up a biological tolerance value (BAT) for o-cresol, a urinary concentration of 3 mg/l o-cresol should be in accordance with the current MAK value of 50 ppm toluene.

Automatic feedback control of a vapor generation system using off-The-Shelf components

A solvent vapor generation and control system was assembled that provided accurate and reliable vapor concentrations over extended periods, functioned without operator intervention, used only off-the-shelf hardware and software components, and required no special programming or electronics expertise to construct, configure, or operate. Evaluations using toluene demonstrated excellent concentration control over 4- to 72-h periods of unattended operation. Time-weighted average toluene concentrations were maintained within 1 ppm of the target over a range of 100–900 ppm, with root-mean-square variability about the setpoint of 3–5% of setpoint for all but the lowest setpoint used. Concentrations were maintained within 5% of setpoint 80–90% of the time for higher setpoints, and within 10% of setpoint over 95% of the time for all but the lowest setpoint used. Excursions of more than 10% above or below the setpoint were rare. Reduced control effectiveness at the lower setpoints was attributed to inherent but reducible limitations in the system's design and operating mode. The system clearly demonstrated that accurate, precise, and reliable systems may be constructed and operated without the need for custom hardware or software development or special expertise in either electronics or computer programming. Additional study is needed to evaluate the performance of this and similar systems with the range of volatile and semivolatile materials of health or materials science interest; however, there appears to be no inherent limitations in the technology that would prevent its ready application to a variety of research uses.

Possible ethnic difference in toluene metabolism: A com- parative study among chinese, turkish and japanese sol- vent workers

Toluene metabolism was studied in 192 Chinese workers in comparison with that in 130 Japanese and 17 Turks. Time-weighted average concentrations of toluene in the breathing zone of workers were measured utilizing passive dosimeters, and hippuric acid (HA) and o-cresol (oC) concentrations in shiftend spot urine samples by high-performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. Under similar exposure conditions, male Japanese excreted almost twice as much HA as male Chinese, although such difference was less marked between female Chinese and Japanese. In contrast, the excretion of oC did not differ between the two ethnic groups. The ratio of oC over HA was highest among Turkish workers followed by Chinese, and lowest among Japanese. Possible roles of differences in toxicogenetics as well as in life patterns were discussed.

Exposure to toluene and urinary hippuric acid excretion in a group of heliorotagravure printing workers.

The influence of a number of factors possibly affecting the relation between urinary hippuric acid excretion and the exposure level to toluene was studied in a population of heliorotagravure printers. It was observed that the hippuric acid excretion rates, after 4 h and 8 h from the onset of the exposure, were in better agreement with the average toluene concentrations in work room air than either the urinary metabolite concentrations alone or corrected for urine density. Apart from differences in exposure level, a substantial proportion of the interindividual variability in hippuric acid excretion could be explained by differences in energetical load during the exposure. It was thereby not possible to elucidate the full extent to which this factor influences the metabolite excretion. In good agreement with previous experimental findings, the hippuric acid excretion rate apparently does not depend on the time of urine sampling during the exposure, provided that at least 4 h have elapsed from the onset.

某造船工場,Thinner使用塗装作業場における作業員の尿中馬尿酸,メチル馬尿酸量について : Thinner中毒第8報,有機溶剤中毒第12報

We measured, during a week, the urinary hippuric acid (H.A.) and m-and p-methyl hippuric acid (M.H.A) of workers exposed to thinner containing toluene and m-and p-xylene in their routine spraying or painting work in a ship-building yard, and also, during a month, total amount of H.A. and M.H.A. Average toluene and xylene inhaled were calculated from the chart indicating relationship between toluene density and urinary H.A., or m-and p-xylene density and urinary M.H.A. described previously. The following results were obtained. 1) The concentration of the urinary H.A. varied in parallel with M.H.A. The mole ratio of toluene to m-and p-xylene in the thinner on the 13th of March was similar to that of urinary H.A. to M.H.A. in the workers using the thinner. As to the evaporation ration of the thinner, the ratio of toluene to m-and p-xylene in the air is thought to be different. Therefore, determination of the ratio of H.A. to M.H.A. appears to be suitable to know the ratio of toluene and m-and p-xylene inhaled. 2) We could calculate the average toluene and m-and p-xylene density inhaled respectively and also sum of them from urinary H.A. and M.H.A., We could check the day when workers were thought to be exposed to over 200 p.p.m. of toluene plus xylene concentration. 3) We also succeeded in checking the day exposure of workers to 200 p.p.m. of toluene plus xylene using the following equation. (H.A.conc. in working time, (mg/ml)) / (H.A.conc. exposed to 200 p.p.m. of toluene, (5.74 mg/ml )) + (M.H.A.conc. in working time, (mg/ml)) / (M.H.A.conc. exposed to 200 p.p.m. of xylene, (4.56 mg/ml)) &gEl;1……………(1) or simply, (H.A. + M.H.A.conc. (mg/ml)) / (5.15 mg/ml)&gEl;1……………(2) Equation (2) was useful in the case in which sum of H.A. and M.H.A. concentration had been measured by simple paperchromatography with buthanol-acetic acid-water as a developing solvent. (4) Daily urinary H.A. and M.H.A. concentrations varied distinctly, depending on the kinds and duration of work. Therefore, determination of the average concentrations of toluene and xylene or of urinary H.A. and M.H.A. during a week or a month is necessary.