Socioeconomic and personal behavioral factors affecting children's exposure to VOCs in urban areas in Korea.

Science.gov (United States)

Byun, Hyaejeong; Ryu, Kyongnam; Jang, Kyungjo; Bae, Hyunjoo; Kim, Dongjin; Shin, Hosung; Chu, Jangmin; Yoon, Chungsik

2010-02-01

Volatile organic compounds (VOCs) are known to cause adverse health effects. We investigated the relationships between children's VOC exposure and socioeconomic and human activity factors with passive personal samplers, questionnaires, and time-activity diaries (TAD). Statistical analyses were conducted using SAS 9.1, and the results were organized using SigmaPlot 8.0 software. Chemicals such as benzene, toluene, 2-butanone, ethylbenzene, xylene, chloroform, n-hexane, heptane, and some kinds of decanes, which are known to adversely affect public health, were identified in measured samples. These were mainly emitted from outdoor sources (e.g., vehicular traffic) or indoor sources (e.g., household activities such as cooking and cleaning) or both. We concluded that region was the most important socioeconomic factor affecting children's VOC exposure, and the significant compounds were n-hexane (p = 0.006), 1,1,1-trichloroethane (p = 0.001), benzene (p = 0.003), toluene (p = 0.002), ethylbenzene (p = 0.020), m-, p-xylene (p = 0.014), dodecane (p = 0.003), and hexadecane (p = 0.001). Parental education, year of home construction and type of housing were also slightly correlated with personal VOC exposure. Only the concentration of o-xylene (p = 0.027) was significantly affected by the parental education, and the concentrations of benzene (p = 0.030) and 2-butanone (p = 0.049) by the type of housing. Also, tridecane (p = 0.049) and n-hexane (p = 0.033) were significantly associated with the year of home construction. When household activities such as cooking were performed indoors, children's VOC concentrations tended to be higher, especially for n-hexane, chloroform, heptane, toluene (p factors simultaneously, socioeconomic factors such as region had a greater effect on children's VOC exposures than indoor activities. From this study, we can suggest that socioeconomic factors as well as environmental factors should be considered when formulating environmental policy to

Adsorption of VOCs on reduced graphene oxide.

Science.gov (United States)

Yu, Lian; Wang, Long; Xu, Weicheng; Chen, Limin; Fu, Mingli; Wu, Junliang; Ye, Daiqi

2018-05-01

A modified Hummer's method was adopted for the synthesis of graphene oxide (GO) and reduced graphene oxide (rGO). It was revealed that the modified method is effective for the production of GO and rGO from graphite. Transmission electron microscopy (TEM) images of GO and rGO showed a sheet-like morphology. Because of the presence of oxygenated functional groups on the carbon surface, the interlayer spacing of the prepared GO was higher than that of rGO. The presence of OH and CO groups in the Fourier transform infrared spectra (FTIR) spectrum and G-mode and 2D-mode in Raman spectra confirmed the synthesis of GO and rGO. rGO (292.6m 2 /g) showed higher surface area than that of GO (236.4m 2 /g). The prepared rGO was used as an adsorbent for benzene and toluene (model pollutants of volatile organic compounds (VOCs)) under dynamic adsorption/desorption conditions. rGO showed higher adsorption capacity and breakthrough times than GO. The adsorption capacity of rGO for benzene and toluene was 276.4 and 304.4mg/g, respectively. Desorption experiments showed that the spent rGO can be successfully regenerated by heating at 150.0°C. Its excellent adsorption/desorption performance for benzene and toluene makes rGO a potential adsorbent for VOC adsorption. Copyright © 2017. Published by Elsevier B.V.

Pollution characteristic of VOCs of ambient air in winter and spring in Shijiazhuang City

Directory of Open Access Journals (Sweden)

Qing CHANG

2015-06-01

Full Text Available In order to further explore the pollution characteristics of volatile organic compounds in ambient air in winter and spring in Shijiazhuang City, the pollution characteristics of 62 volatile organic compounds (VOCs, monthly and quarterly variation, the correlation between VOCs and PM2.5, and the main sources of VOCs are investigated by using EPA TO-15 method. It shows that 40 organic compounds of the 64 VOCs have been quantitatively determined in winter and spring in the city, which are mainly acetone, benzene, carbon tetrachloride, dichloromethane, toluene, ethyl acetate, etc.. In the no-quantitatively determined components, higher ethanol, butyl acetate, butane etc. are detected. The VOCs concentration has positive correlation with the PM2.5 concentration during haze days.

Adsorptive performance of chromium-containing ordered mesoporous silica on volatile organic compounds (VOCs

Directory of Open Access Journals (Sweden)

Jianwei Fan

2017-09-01

Full Text Available Volatile organic compounds (VOCs are the primary poisonous emissions into the atmosphere in natural gas exploitation and disposing process. The adsorption method has been widely applied in actual production because of its good features such as low cost, low energy consumption, flexible devices needed, etc. The commonly used adsorbents like activated carbon, silicon molecular sieves and so on are not only susceptible to plugging or spontaneous combustion but difficult to be recycled. In view of this, a new adsorbent (CrSBA15 was made by the co-assembly method to synthesize the ordered mesoporous silica materials with different amounts of chromium to eliminate VOCs. This new adsorbent was characterized by small-angle-X-ray scattering (SAXS, nitrogen adsorption/desorption, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Its adsorption performance to eliminate VOCs (toluene, benzene, cyclohexane and ethyl acetate used as typical pollutants was also tested systematically. Research results indicate that this new adsorbent of CrSBA-15(30, with the silicon/chromium ration being 30, owns the maximum micropore volume, and shows a higher adsorption performance in eliminating toluene, benzene, cyclohexane and ethyl acetate. Besides, it is cost-effective and much easier to be recycled than the activated carbon. In conclusion, CrSBA-15(30 is a good adsorbent to eliminate VOCs with broad application prospects. Keywords: Mesoporous materials, Silicon dioxide, Synthesis, Adsorption, Volatile organic compounds (VOCs, Recyclability, Energy saving

Air exchange rates and migration of VOCs in basements and residences.

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Du, L; Batterman, S; Godwin, C; Rowe, Z; Chin, J-Y

2015-12-01

Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs, and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multitracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walk-through survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52/h, respectively, and had strong and opposite seasonal trends, for example, AERs were highest in residences during the summer, and highest in basements during the winter. Airflows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, for example, 90th percentile benzene, toluene, naphthalene, and limonene concentrations were 4.0, 19.1, 20.3, and 51.0 μg/m(3), respectively; maximum concentrations were 54, 888, 1117, and 134 μg/m(3). Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. Few IAQ studies have examined basements. A sizable volume of air can flow between the basement and living area, and AERs in these two zones can differ considerably. In many residences, the basement contains significant emission sources and contributes a large fraction of VOC concentrations found in the living area. Exposures can be lowered by removing VOC sources from the basement; other exposure management options, such as local ventilation or isolation, are unlikely to be practical. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Monitoring Volatile Organic Compounds (VOCs) in real-time on oil and natural gas production sites

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Lupardus, R.; Franklin, S. B.

2017-12-01

Oil and Natural Gas (O&NG) development, production, infrastructure, and associated processing activities can be a substantial source of air pollution, yet relevant data and real-time quantification methods are lacking. In the current study, O&NG fugitive emissions of Volatile Organic Compounds (VOCs) were quantified in real-time and used to determine the spatial and temporal windows of exposure for proximate flora and fauna. Eleven O&NG sites on the Pawnee National Grassland in Northeastern Colorado were randomly selected and grouped according to production along with 13 control sites from three geographical locations. At each site, samples were collected 25 m from the wellhead in NE, SE, and W directions. In each direction, two samples were collected with a Gasmet DX4040 gas analyzer every hour from 8:00 am to 2:00 pm (6 hours total), July to October, 2016 (N=864). VOC concentrations generally increased during the 6 hr. day with the exception of N2O and were predominately the result of O&NG production and not vehicle exhaust. Thirteen of 24 VOCs had significantly different levels between production groups, frequently above reference standards and at biologically relevant levels for flora and fauna. The most biologically relevant VOCs, found at concentrations exceeding time weighted average permissible exposure limits (TWA PELs), were benzene and acrolein. Generalized Estimating Equations (GEEs) measured the relative quality of statistical models predicting benzene concentrations on sites. The data not only confirms that O&NG emissions are impacting the region, but also that this influence is present at all sites, including controls. Increased real-time VOC monitoring on O&NG sites is required to identify and contain fugitive emissions and to protect human and environmental health.

Volatile organic compounds (VOCs) in air from Nisyros Island (Dodecanese Archipelago, Greece): Natural versus anthropogenic sources

International Nuclear Information System (INIS)

Tassi, F.; Capecchiacci, F.; Giannini, L.; Vougioukalakis, G.E.; Vaselli, O.

2013-01-01

This study presents the chemical composition of VOCs in air and gas discharges collected at Nisyros Island (Dodecanese Archipelago, Greece). The main goals are i) to discriminate between natural and anthropogenic VOC sources and ii) to evaluate their impact on local air quality. Up to 63 different VOCs were recognized and quantitatively determined in 6 fumaroles and 19 air samples collected in the Lakki caldera, where fumarolic emissions are located, and the outer ring of the island, including the Mandraki village and the main harbor. Air samples from the crater area show significant concentrations of alkanes, alkenes, cyclic, aromatics, and S- and O-bearing heterocycles directly deriving from the hydrothermal system, as well as secondary O-bearing compounds from oxidation of primary VOCs. At Mandraki village, C 6 H 6 /Σ(methylated aromatics) and Σ(linear)/Σ(branched) alkanes ratios 2 O–CO 2 –H 2 S rich and discharge a large variety of VOC species. •Benzene/toluene ratios identify anthropogenic and natural sources of VOCs in air. •Aldehydes in air are produced by oxidation of alkanes and alkenes. •Geogenic furans and hydrogenated halocarbons in air are recalcitrant. -- Anthropogenic and natural VOCs in air are distinguished on the basis of aromatic, O-substituted, S-substituted and halogenated compounds

Dynamic permeation sources for volatile organic compounds (VOCS): 'a standards test environment' nuclear track detector

International Nuclear Information System (INIS)

Hussain, A.; Marr, I.

2000-01-01

The generation of a test environment for trace VOCs in urban air or work place has never been easy. This investigation is concerned with the loss rates of VOCs through polythene membrane of different thickness. Permeation glass sample bottles were suspended in the chamber with water jacket at 24 deg. C -+ 0.5 deg. temperature. The condenser was connected with a stream of nitrogen gas at a flow rate of 75-ml min/sup -1 and further diluted with air 500-ml min/sup -1/. The loss in weight of VOCs in each bottle was determined regularly, every 24 hours, with a good agreement. The loss rate depends upon temperature of the bath, thickness of the polythene, internal diameter of the permeation bottle opening. However the loss rate from permeation tubes also depends upon the solubility of the VOCs in the polymer. It is generally believed that the vapors of VOCs in the permeation bottle are dissolved in the polythene sheet (making some sort of solution) and are eventually evaporated out of it. It was observed that the loss rate per minute for benzene > toluene. This simple technique described 'generation of test environment through dynamic permeation source' could be suitable for preparing mixture of benzene, toluene and xylene in atmosphere at ppm levels or lower, with good stability, reliability and also for other compounds of atmospheric interest. (author)

[Pollution characteristics and health risk assessment of atmospheric volatile organic compounds (VOCs) in pesticide factory].

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Tan, Bing; Wang, Tie-Yu; Pang, Bo; Zhu, Zhao-Yun; Wang, Dao-Han; Lü, Yong-Long

2013-12-01

A method for determining volatile organic compounds (VOCs) in air by summa canister collecting and gas chromatography/ mass spectroscopy detecting was adopted. Pollution condition and characteristics of VOCs were discussed in three representative pesticide factories in Zhangjiakou City, Hebei Province. Meanwhile, an internationally recognized four-step evaluation model of health risk assessment was applied to preliminarily assess the health risk caused by atmospheric VOCs in different exposure ways, inhalation and dermal exposure. Results showed that serious total VOCs pollution existed in all factories. Concentrations of n-hexane (6161.90-6910.00 microg x m(-3)), benzene (126.00-179.30 microg x m(-3)) and 1,3-butadiene (115.00-177.30 microg x m(-3)) exceeded the Chronic Inhalation Reference Concentrations recommended by USEPA, corresponding to 700, 30 and 2 microg x m(-3), respectively. Concentration of dichloromethane (724.00 microg x m(-3)) in factory B was also higher than the reference concentration (600 microg x m(-3)). Results of health risk assessment indicated that non-carcinogenic risk indexes of VOCs ranged from 1.00E-04 to 1.00E + 00 by inhalation exposure, and 1.00E-09 to 1.00E-05 by dermal exposure. Risk indexes of n-hexane and dichloromethane by inhalation exposure in all factories exceeded 1, and risk index of benzene by inhalation in factory B was also higher than 1. Carcinogenic risk indexes exposed to VOCs ranged from 1.00E-08 to 1.00E-03 by inhalation exposure and 1. oo00E -13 to 1.00E-08 by dermal exposure. Cancer risk of 1,3-butadiene by inhalation exceeded 1.0E-04, which lead to definite risk, and those of benzene by inhalation also exceeded the maximum allowable level recommended by International Commission on Radiological Protection (5.0E-05). The risks of dermal exposure presented the same trend as inhalation exposure, but the level was much lower than that of inhalation exposure. Thus, inhalation exposure of atmospheric VOCs was the

Source profiles of volatile organic compounds (VOCs) measured in China: Part I

Science.gov (United States)

Liu, Ying; Shao, Min; Fu, Linlin; Lu, Sihua; Zeng, Limin; Tang, Dagang

The profiles of major volatile organic compound (VOC) sources in China, including vehicle exhaust, gasoline vapor, paint, asphalt, industrial and residential coal burning, biomass burning, and the petrochemical industry, were experimentally determined. Source samples were taken using a dilution chamber for mobile and stationary sources, biomass burning in an actual Chinese farmer's house, and ambient air in a petrochemical industrial area. The concentrations of 92 VOC species were quantified using canister sampling and a gas chromatography-flame ionization detection/mass spectrometry system, and VOC source profiles were developed for source apportionment of VOCs in the Pearl River Delta region. Based on the measurement of source profiles, possible tracers for various emission sources were identified; e.g., 2-methylpentane and 1,3-butadiene could be used as tracers for vehicle exhaust; the characteristic compounds of architectural coating were aromatics such as toluene and m, p-xylene; the light hydrocarbons, namely n-butane, trans-2-butene, and n-pentane, dominated the composition of gasoline vapor; and n-nonane, n-decane, and n-undecane were found to be typical of diesel vapor and asphalt application processes. As different emission sources are characterized by overlapping VOC species, the ratio of possible VOC tracers could be used to assess the contribution of various sources. The ratios between n-butane and isobutane, 1,3-butadiene and isoprene, and the ratios of aromatics (e.g., toluene to benzene and ethylbenzene to m, p-xylene) in the measured sources were compared.

Benzene observations and source appointment in a region of oil and natural gas development

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Halliday, Hannah Selene

Benzene is a primarily anthropogenic volatile organic compound (VOC) with a small number of well characterized sources. Atmospheric benzene affects human health and welfare, and low level exposure (Atmospheric Observatory (PAO) in Colorado to investigate how O&NG development impacts air quality within the Wattenburg Gas Field (WGF) in the Denver-Julesburg Basin. The measurements were carried out in July and August 2014 as part of NASA's DISCOVER-AQ field campaign. The PTR-QMS data were supported by pressurized whole air canister samples and airborne vertical and horizontal surveys of VOCs. Unexpectedly high benzene mixing ratios were observed at PAO at ground level (mean benzene = 0.53 ppbv, maximum benzene = 29.3 ppbv), primarily at night (mean nighttime benzene = 0.73 ppbv). These high benzene levels were associated with southwesterly winds. The airborne measurements indicate that benzene originated from within the WGF, and typical source signatures detected in the canister samples implicate emissions from O&NG activities rather than urban vehicular emissions as primary benzene source. This conclusion is backed by a regional toluene-to-benzene ratio analysis which associated southerly flow with vehicular emissions from the Denver area. Weak benzene-to-CO correlations confirmed that traffic emissions were not responsible for the observed high benzene levels. Previous measurements at the Boulder Atmospheric Observatory (BAO) and our data obtained at PAO allow us to locate the source of benzene enhancements between the two atmospheric observatories. Fugitive emissions of benzene from O&NG operations in the Platteville area are discussed as the most likely causes of enhanced benzene levels at PAO. A limited information source attribution with the PAO dataset was completed using the EPA's positive matrix factorization (PMF) source receptor model. Six VOCs from the PTR-QMS measurement were used along with CO and NO for a total of eight chemical species. Six sources

Atmospheric benzene observations from oil and gas production in the Denver-Julesburg Basin in July and August 2014

Science.gov (United States)

Halliday, Hannah S.; Thompson, Anne M.; Wisthaler, Armin; Blake, Donald R.; Hornbrook, Rebecca S.; Mikoviny, Tomas; Müller, Markus; Eichler, Philipp; Apel, Eric C.; Hills, Alan J.

2016-09-01

High time resolution measurements of volatile organic compounds (VOCs) were collected using a proton-transfer-reaction quadrupole mass spectrometry (PTR-QMS) instrument at the Platteville Atmospheric Observatory (PAO) in Colorado to investigate how oil and natural gas (O&NG) development impacts air quality within the Wattenburg Gas Field (WGF) in the Denver-Julesburg Basin. The measurements were carried out in July and August 2014 as part of NASA's "Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) field campaign. The PTR-QMS data were supported by pressurized whole air canister samples and airborne vertical and horizontal surveys of VOCs. Unexpectedly high benzene mixing ratios were observed at PAO at ground level (mean benzene = 0.53 ppbv, maximum benzene = 29.3 ppbv), primarily at night (mean nighttime benzene = 0.73 ppbv). These high benzene levels were associated with southwesterly winds. The airborne measurements indicate that benzene originated from within the WGF, and typical source signatures detected in the canister samples implicate emissions from O&NG activities rather than urban vehicular emissions as primary benzene source. This conclusion is backed by a regional toluene-to-benzene ratio analysis which associated southerly flow with vehicular emissions from the Denver area. Weak benzene-to-CO correlations confirmed that traffic emissions were not responsible for the observed high benzene levels. Previous measurements at the Boulder Atmospheric Observatory (BAO) and our data obtained at PAO allow us to locate the source of benzene enhancements between the two atmospheric observatories. Fugitive emissions of benzene from O&NG operations in the Platteville area are discussed as the most likely causes of enhanced benzene levels at PAO.

[Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].

Science.gov (United States)

Cui, Ru; Ma, Yong-Liang

2013-12-01

Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

Characterization and health risk assessment of VOCs in occupational environments in Buenos Aires, Argentina

Science.gov (United States)

Colman Lerner, J. E.; Sanchez, E. Y.; Sambeth, J. E.; Porta, A. A.

2012-08-01

To detect volatile organic compounds (VOCs) in indoor air in small enterprises in La Plata city and surrounding areas, sampling was conducted using passive diffusion monitors (3M-3500) and analysis of the samples were performed byCG-FID. Analytic methodology was optimized for 23 VOCs (n-alkanes, cycloalkanes, aromatic and chlorinated compounds, ketones and terpenes compounds) by determining the recovery factor and detection limit for each analyte. Different recovery values were obtained by desorbing with a mixture of dichloromethane: methanol (50:50), with a standard deviation lower than 5%. Enterprise analyzed included chemical analysis laboratories, sewing workrooms, electromechanical repair and car painting centers, take away food shops, and a photocopy center. The highest levels of VOCs were found to be in electromechanical repair and car painting centers (hexane, BTEX, CHCl3, CCl4) followed by chemical analysis laboratories and sewing workrooms. Cancer and noncancer risks were assessed using conventional approaches (HQ and LCR, US EPA) using the benzene, trichloroethylene, chloroform for cancer risk, and toluene, xylene and n-hexane, for noncancer risks as markers. The results showed different LCR for benzene and trichloroethylene between the different indoor environments analyzed (electromechanical repair and car painting center ≫ others) and chloroform (laboratory > others), but comparing with the results obtained by other research, are in similar order of magnitude for equivalents activities. Similar finding were founded for HQ. Comparing these results with the worker protection legislation the electromechanical repair and car painting center and chemical analysis laboratories are close to the limits advised by OSHA and ACGIH. These facts show the importance of the use of abatement technologies for the complete reduction of VOCs levels, to mitigate their impact in the worker's health and their venting to the atmosphere.

Measuring OVOCs and VOCs by PTR-MS in an urban roadside microenvironment of Hong Kong: relative humidity and temperature dependence, and field intercomparisons

Science.gov (United States)

Cui, Long; Zhang, Zhou; Huang, Yu; Lee, Shun Cheng; Blake, Donald Ray; Ho, Kin Fai; Wang, Bei; Gao, Yuan; Wang, Xin Ming; Kwok Keung Louie, Peter

2016-12-01

Volatile organic compound (VOC) control is an important issue of air quality management in Hong Kong because ozone formation is generally VOC limited. Several oxygenated volatile organic compound (OVOC) and VOC measurement techniques - namely, (1) offline 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling followed by high-performance liquid chromatography (HPLC) analysis; (2) online gas chromatography (GC) with flame ionization detection (FID); and (3) offline canister sampling followed by GC with mass spectrometer detection (MSD), FID, and electron capture detection (ECD) - were applied during this study. For the first time, the proton transfer reaction-mass spectrometry (PTR-MS) technique was also introduced to measured OVOCs and VOCs in an urban roadside area of Hong Kong. The integrated effect of ambient relative humidity (RH) and temperature (T) on formaldehyde measurements by PTR-MS was explored in this study. A Poly 2-D regression was found to be the best nonlinear surface simulation (r = 0.97) of the experimental reaction rate coefficient ratio, ambient RH, and T for formaldehyde measurement. This correction method was found to be better than correcting formaldehyde concentrations directly via the absolute humidity of inlet sample, based on a 2-year field sampling campaign at Mong Kok (MK) in Hong Kong. For OVOC species, formaldehyde, acetaldehyde, acetone, and MEK showed good agreements between PTR-MS and DNPH-HPLC with slopes of 1.00, 1.10, 0.76, and 0.88, respectively, and correlation coefficients of 0.79, 0.75, 0.60, and 0.93, respectively. Overall, fair agreements were found between PTR-MS and online GC-FID for benzene (slope = 1.23, r = 0.95), toluene (slope = 1.01, r = 0.96) and C2-benzenes (slope = 1.02, r = 0.96) after correcting benzene and C2-benzenes levels which could be affected by fragments formed from ethylbenzene. For the intercomparisons between PTR-MS and offline canister measurements by GC-MSD/FID/ECD, benzene showed good agreement

Atmospheric Benzene Observations from an Oil and Gas Field in the Denver Julesburg Basin in July and August 2014

Science.gov (United States)

Halliday, Hannah S.; Thompson, Anne M.; Wisthaler, Armin; Blake, Donald; Hornbrook, Rebecca S.; Mikoviny, Tomas; Mueller, Markus; Eichler, Philipp; Apel, Eric C.; Hills, Alan

2016-01-01

High time resolution measurements of volatile organic compounds (VOCs) were collectedusing a proton-transfer-reaction quadrupole mass spectrometry (PTR-QMS) instrument at the PlattevilleAtmospheric Observatory (PAO) in Colorado to investigate how oil and natural gas (ONG) developmentimpacts air quality within the Wattenburg Gas Field (WGF) in the Denver-Julesburg Basin. The measurementswere carried out in July and August 2014 as part of NASAs Deriving Information on Surface Conditions fromColumn and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign. ThePTR-QMS data were supported by pressurized whole air canister samples and airborne vertical and horizontalsurveys of VOCs. Unexpectedly high benzene mixing ratios were observed at PAO at ground level (meanbenzene 0.53 ppbv, maximum benzene 29.3 ppbv), primarily at night (mean nighttime benzene 0.73ppbv). These high benzene levels were associated with southwesterly winds. The airborne measurementsindicate that benzene originated from within the WGF, and typical source signatures detected in the canistersamples implicate emissions from ONG activities rather than urban vehicular emissions as primary benzenesource. This conclusion is backed by a regional toluene-to-benzene ratio analysis which associated southerlyflow with vehicular emissions from the Denver area. Weak benzene-to-CO correlations confirmed that trafficemissions were not responsible for the observed high benzene levels. Previous measurements at the BoulderAtmospheric Observatory (BAO) and our data obtained at PAO allow us to locate the source of benzeneenhancements between the two atmospheric observatories. Fugitive emissions of benzene from ONGoperations in the Platteville area are discussed as the most likely causes of enhanced benzene levels at PAO.

Improved performance of parallel surface/packed-bed discharge reactor for indoor VOCs decomposition: optimization of the reactor structure

International Nuclear Information System (INIS)

Jiang, Nan; Hui, Chun-Xue; Li, Jie; Lu, Na; Shang, Ke-Feng; Wu, Yan; Mizuno, Akira

2015-01-01

The purpose of this paper is to develop a high-efficiency air-cleaning system for volatile organic compounds (VOCs) existing in the workshop of a chemical factory. A novel parallel surface/packed-bed discharge (PSPBD) reactor, which utilized a combination of surface discharge (SD) plasma with packed-bed discharge (PBD) plasma, was designed and employed for VOCs removal in a closed vessel. In order to optimize the structure of the PSPBD reactor, the discharge characteristic, benzene removal efficiency, and energy yield were compared for different discharge lengths, quartz tube diameters, shapes of external high-voltage electrode, packed-bed discharge gaps, and packing pellet sizes, respectively. In the circulation test, 52.8% of benzene was removed and the energy yield achieved 0.79 mg kJ −1 after a 210 min discharge treatment in the PSPBD reactor, which was 10.3% and 0.18 mg kJ −1 higher, respectively, than in the SD reactor, 21.8% and 0.34 mg kJ −1 higher, respectively, than in the PBD reactor at 53 J l −1 . The improved performance in benzene removal and energy yield can be attributed to the plasma chemistry effect of the sequential processing in the PSPBD reactor. The VOCs mineralization and organic intermediates generated during discharge treatment were followed by CO x selectivity and FT-IR analyses. The experimental results indicate that the PSPBD plasma process is an effective and energy-efficient approach for VOCs removal in an indoor environment. (paper)

Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

International Nuclear Information System (INIS)

Kim, Jo-Chun

2011-01-01

The removal efficiency of n-decane (C 10 H 22 ) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C 6 H 14 ), n-butane (C 4 H 10 ), and methane (CH 4 ) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C 6 H 6 ) decomposition was the lowest and that of toluene (C 7 H 8 ), ethylbenzene (C 8 H 10 ), and p-xylene (C 8 H 10 ) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO 2 , O 3 , and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

Biofiltration of airborne VOCs with green wall systems-Microbial and chemical dynamics.

Science.gov (United States)

Mikkonen, A; Li, T; Vesala, M; Saarenheimo, J; Ahonen, V; Kärenlampi, S; Blande, J D; Tiirola, M; Tervahauta, A

2018-05-06

Botanical air filtration is a promising technology for reducing indoor air contaminants, but the underlying mechanisms need better understanding. Here, we made a set of chamber fumigation experiments of up to 16 weeks of duration, to study the filtration efficiencies for seven volatile organic compounds (VOCs; decane, toluene, 2-ethylhexanol, α-pinene, octane, benzene, and xylene) and to monitor microbial dynamics in simulated green wall systems. Biofiltration functioned on sub-ppm VOC levels without concentration-dependence. Airflow through the growth medium was needed for efficient removal of chemically diverse VOCs, and the use of optimized commercial growth medium further improved the efficiency compared with soil and Leca granules. Experimental green wall simulations using these components were immediately effective, indicating that initial VOC removal was largely abiotic. Golden pothos plants had a small additional positive impact on VOC filtration and bacterial diversity in the green wall system. Proteobacteria dominated the microbiota of rhizosphere and irrigation water. Airborne VOCs shaped the microbial communities, enriching potential VOC-utilizing bacteria (especially Nevskiaceae and Patulibacteraceae) in the irrigation water, where much of the VOC degradation capacity of the biofiltration systems resided. These results clearly show the benefits of active air circulation and optimized growth media in modern green wall systems. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Meteorological aspects of benzene transport, dispersion and personal exposure in Valdez, Alaska

Energy Technology Data Exchange (ETDEWEB)

Murray, D.R.; Ball, R.J. [TRC Environmental Corp., Windsor, CT (United States)

1994-12-31

The Valdez Air Health Study (VAHS) was conducted in Valdez, Alaska to determine the personal exposure of the residential population of Valdez to certain volatile organic compounds (VOCs). The VAHS used the EPA`s Total Exposure Assessment Methodology (TEAM) with continuous meteorology, air quality and intense tracer measurements to monitor personal and indoor/outdoor concentrations of VOCs in the community. The Valdez fjord is the site of the Alyeska Marine Terminal, the largest crude oil loading terminal in the United States, with a maximum capacity of 2.2 million barrels per day. The Alyeska Marine Terminal is the transfer point for Prudhoe Bay crude oil from the pipeline to marine tankers. During 1990, the terminal and marine tankers were estimated to emit approximately 450 metric tonnes/year of benzene to the air at an average throughput of 1.8 million barrels/day while benzene emissions from other sources in the basin were estimated to be approximately 3 tonnes/year.

Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

Energy Technology Data Exchange (ETDEWEB)

Tan, C.; Ong, H.Y.; Kok, P.W. [and others

1996-12-31

The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

Energy Technology Data Exchange (ETDEWEB)

Kim, Jo-Chun [Department of Environmental Engineering, Konkuk University, Seoul (Korea, Republic of)

2011-07-01

The removal efficiency of n-decane (C{sub 10}H{sub 22}) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C{sub 6}H{sub 14}), n-butane (C{sub 4}H{sub 10}), and methane (CH{sub 4}) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C{sub 6}H{sub 6}) decomposition was the lowest and that of toluene (C{sub 7}H{sub 8}), ethylbenzene (C{sub 8}H{sub 10}), and p-xylene (C{sub 8}H{sub 10}) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO{sub 2}, O{sub 3}, and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

Volatile organic compound (VOC) determination in working atmospheres; Determinacion de compuestos organicos volatiles (VOC) en ambiente laboral

Energy Technology Data Exchange (ETDEWEB)

Blass A, Georgina; Panama T, Luz A; Corrales C, Deyanira [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2003-07-01

The present work describes, in a synthesized way, the implementation and application of procedures based on the normativity related to the subject of the volatile organic compounds (Volatile Organic Compounds VOC), that allow to sample, quantify and evaluate the present contamination in the working atmosphere of a refinery due to the fugitive emissions of VOC and other substances. In accordance with the corresponding normativity, more than 189 organic compounds denominated dangerous air polluting agents (Hazardous Air Pollutants, HAP) can be found in a working atmosphere, but they are the 11 main HAP that can be found in a refinery. In the present article the work made for the sampling and quantification of 5 of the 11 dangerous polluting agents of the air: benzene, toluene, xylene, iso-octane and naphthalene. [Spanish] El presente trabajo describe, de manera sintetizada, la implementacion y aplicacion de procedimientos basados en la normatividad relacionada al tema de los compuestos organicos volatiles (Volatil Organic Compounds, VOC), que permiten muestrear, cuantificar y evaluar la contaminacion presente en el ambiente laboral de una refineria debido a las emisiones fugitivas de VOC y otras sustancias. De acuerdo con la normatividad correspondiente, mas de 189 compuestos organicos denominados contaminantes peligrosos del aire (Hazardous Air Pollutants, HAP), pueden ser encontrados en un ambiente laboral, pero son 11 los principales HAP que pueden ser hallados en una refineria. En el presente articulo se informa el trabajo realizado para el muestreo y cuantificacion de 5 de los 11 contaminantes peligrosos del aire: benceno, tolueno, xileno, iso-octano y naftaleno.

VOC flux measurements using a novel Relaxed Eddy Accumulation GC-FID system in urban Houston, Texas

Science.gov (United States)

Park, C.; Schade, G.; Boedeker, I.

2008-12-01

Houston experiences higher ozone production rates than most other major cities in the US, which is related to high anthropogenic VOC emissions from both area/mobile sources (car traffic) and a large number of petrochemical facilities. The EPA forecasts that Houston is likely to still violate the new 8-h NAAQS in 2020. To monitor neighborhood scale pollutant fluxes, we established a tall flux tower installation a few kilometers north of downtown Houston. We measure energy and trace gas fluxes, including VOCs from both anthropogenic and biogenic emission sources in the urban surface layer using eddy covariance and related techniques. Here, we describe a Relaxed Eddy Accumulation (REA) system combined with a dual-channel GC-FID used for VOC flux measurements, including first results. Ambient air is sampled at approximately 15 L min-1 through a 9.5 mm OD PFA line from 60 m above ground next to a sonic anemometer. Subsamples of this air stream are extracted through an ozone scrubber and pushed into two Teflon bag reservoirs, from which they are transferred to the GC pre-concentration units consisting of carbon-based adsorption traps encapsulated in heater blocks for thermal desorption. We discuss the performance of our system and selected measurement results from the 2008 spring and summer seasons in Houston. We present diurnal variations of the fluxes of the traffic tracers benzene, toluene, ethylbenzene, and xylenes (BTEX) during different study periods. Typical BTEX fluxes ranged from -0.36 to 3.10 mg m-2 h-1 for benzene, and -0.47 to 5.04 mg m-2 h-1 for toluene, and exhibited diurnal cycles with two dominant peaks related to rush-hour traffic. A footprint analysis overlaid onto a geographic information system (GIS) will be presented to reveal the dominant emission sources and patterns in the study area.

Temporal variability and sources of VOCs in urban areas of the eastern Mediterranean

Directory of Open Access Journals (Sweden)

C. Kaltsonoudis

2016-11-01

Full Text Available During the summer of 2012 volatile organic compounds (VOCs were monitored by proton transfer reaction mass spectrometry (PTR-MS in urban sites, in Athens and Patras, two of the largest cities in Greece. Also, during the winter of 2013, PTR-MS measurements were conducted in the center of the city of Athens. Positive matrix factorization (PMF was applied to the VOC measurements to gain insights about their sources. In summer most of the measured VOCs were due to biogenic and traffic emissions. Isoprene, monoterpenes, and several oxygenated VOCs (oVOCs originated mainly from vegetation either directly or as oxidation products. Isoprene average concentrations in Patras and Athens were 1 and 0.7 ppb respectively, while the monoterpene concentrations were 0.3 and 0.9 ppb respectively. Traffic was the main source of aromatic compounds during summer. For Patras and Athens the average concentrations of benzene were 0.1 and 0.2 ppb, of toluene 0.3 and 0.8 ppb, and of the xylenes 0.3 and 0.7 ppb respectively. Winter measurements in Athens revealed that biomass burning used for residential heating was a major VOC source contributing both aromatic VOCs and biogenic compounds such as monoterpenes. Several episodes related to biomass burning were identified and emission ratios (ERs and emission factors (EFs were estimated.

Estimation of sources and factors affecting indoor VOC levels using basic numerical methods

Directory of Open Access Journals (Sweden)

Sibel Mentese

2016-11-01

Full Text Available Volatile Organic Compounds (VOCs are a concern due to their adverse health effects and extensive usage. Levels of indoor VOCs were measured in six homes located in three different towns in Çanakkale, Turkey. Monthly indoor VOC samples were collected by passive sampling throughout a year. The highest levels of total volatile organic compounds (TVOC, benzene, toluene, and xylenes occurred in industrial, rural, and urban sites in a descending order. VOC levels were categorized as average values annually, during the heating period, and non-heating period. Several building/environmental factors together with occupants’ habits were scored to obtain a basic indoor air pollution index (IAPi for the homes. Bivariate regression analysis was applied to find the associations between the pollutant levels and home scores. IAPi scores were found to be correlated with average indoor VOC levels. In particular, very strong associations were found for occupants’ habits. Furthermore, observed indoor VOC levels were categorized by using self-organizing map (SOM and two simple scoring approaches, rounded average and maximum value methods, to classify the indoor environments based on their VOC compositions (IAPvoc. Three classes were used for both IAPi and IAPvoc approaches, namely “good”, “moderate”, and “bad”. There is an urgent need for indexing studies to determine the potential sources and/or factors affecting observed VOCs. This study gives a basic but good start for further studies.

Total OH reactivity study from VOC photochemical oxidation in the SAPHIR chamber

Science.gov (United States)

Yu, Z.; Tillmann, R.; Hohaus, T.; Fuchs, H.; Novelli, A.; Wegener, R.; Kaminski, M.; Schmitt, S. H.; Wahner, A.; Kiendler-Scharr, A.

2015-12-01

It is well known that hydroxyl radicals (OH) act as a dominant reactive species in the degradation of VOCs in the atmosphere. In recent field studies, directly measured total OH reactivity often showed poor agreement with OH reactivity calculated from VOC measurements (e.g. Nölscher et al., 2013; Lu et al., 2012a). This "missing OH reactivity" is attributed to unaccounted biogenic VOC emissions and/or oxidation products. The comparison of total OH reactivity being directly measured and calculated from single component measurements of VOCs and their oxidation products gives us a further understanding on the source of unmeasured reactive species in the atmosphere. This allows also the determination of the magnitude of the contribution of primary VOC emissions and their oxidation products to the missing OH reactivity. A series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, to explore in detail the photochemical degradation of VOCs (isoprene, ß-pinene, limonene, and D6-benzene) by OH. The total OH reactivity was determined from the measurement of VOCs and their oxidation products by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS) with a GC/MS/FID system, and directly measured by a laser-induced fluorescence (LIF) at the same time. The comparison between these two total OH reactivity measurements showed an increase of missing OH reactivity in the presence of oxidation products of VOCs, indicating a strong contribution to missing OH reactivity from uncharacterized oxidation products.

VOCs and OVOCs distribution and control policy implications in Pearl River Delta region, China

Science.gov (United States)

Louie, Peter K. K.; Ho, Josephine W. K.; Tsang, Roy C. W.; Blake, Donald R.; Lau, Alexis K. H.; Yu, Jian Zhen; Yuan, Zibing; Wang, Xinming; Shao, Min; Zhong, Liuju

2013-09-01

Ambient air measurements of volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs) were conducted and characterised during a two-year grid study in the Pearl River Delta (PRD) region of southern China. The present grid study pioneered the systematic investigation of the nature and characteristics of complex VOC and OVOC sources at a regional scale. The largest contributing VOCs, accounting over 80% of the total VOCs mixing ratio, were toluene, ethane, ethyne, propane, ethene, butane, benzene, pentane, ethylbenzene, and xylenes. Sub-regional VOC spatial characteristics were identified, namely: i) relatively fresh pollutants, consistent with elevated vehicular and industrial activities, around the PRD estuary; and ii) a concentration gradient with higher mixing ratios of VOCs in the west as compared with the eastern part of PRD. Based on alkyl nitrate aging determination, a high hydroxyl radical (OH) concentration favoured fast hydrocarbon reactions and formation of locally produced ozone. The photochemical reactivity analysis showed aromatic hydrocarbons and alkenes together consisted of around 80% of the ozone formation potential (OFP) among the key VOCs. We also found that the OFP from OVOCs should not be neglected since their OFP contribution was more than one-third of that from VOCs alone. These findings support the choice of current air pollution control policy which focuses on vehicular sources but warrants further controls. Industrial emissions and VOCs emitted by solvents should be the next targets for ground-level ozone abatement.

Comparison of different real time VOC measurement techniques in a ponderosa pine forest

Directory of Open Access Journals (Sweden)

L. Kaser

2013-03-01

Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study

Health Risk Assessment of Inhalation Exposure to Formaldehyde and Benzene in Newly Remodeled Buildings, Beijing

Science.gov (United States)

Huang, Lihui; Mo, Jinhan; Sundell, Jan; Fan, Zhihua; Zhang, Yinping

2013-01-01

Objective To assess health risks associated with inhalation exposure to formaldehyde and benzene mainly emitted from building and decoration materials in newly remodeled indoor spaces in Beijing. Methods We tested the formaldehyde and benzene concentrations in indoor air of 410 dwellings and 451 offices remodeled within the past year, in which the occupants had health concerns about indoor air quality. To assess non-carcinogenic health risks, we compared the data to the health guidelines in China and USA, respectively. To assess carcinogenic health risks, we first modeled indoor personal exposure to formaldehyde and benzene using the concentration data, and then estimated the associated cancer risks by multiplying the indoor personal exposure by the Inhalation Unit Risk values (IURs) provided by the U.S. EPA Integrated Risk Information System (U.S. EPA IRIS) and the California Office of Environmental Health Hazard Assessment (OEHHA), respectively. Results (1) The indoor formaldehyde concentrations of 85% dwellings and 67% offices were above the acute Reference Exposure Level (REL) recommended by the OEHHA and the concentrations of all tested buildings were above the chronic REL recommended by the OEHHA; (2) The indoor benzene concentrations of 12% dwellings and 32% offices exceeded the reference concentration (RfC) recommended by the U.S. EPA IRIS; (3) The median cancer risks from indoor exposure to formaldehyde and benzene were 1,150 and 106 per million (based on U.S. EPA IRIS IURs), 531 and 394 per million (based on OEHHA IURs). Conclusions In the tested buildings, formaldehyde exposure may pose acute and chronic non-carcinogenic health risks to the occupants, whereas benzene exposure may pose chronic non-carcinogenic risks to the occupants. Exposure to both compounds is associated with significant carcinogenic risks. Improvement in ventilation, establishment of volatile organic compounds (VOCs) emission labeling systems for decorating and refurbishing materials

Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

Science.gov (United States)

Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Emily Majcher,; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

2015-01-01

Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

Modeling the uncertainty of several VOC and its impact on simulated VOC and ozone in Houston, Texas

Science.gov (United States)

Pan, Shuai; Choi, Yunsoo; Roy, Anirban; Li, Xiangshang; Jeon, Wonbae; Souri, Amir Hossein

2015-11-01

A WRF-SMOKE-CMAQ modeling system was used to study Volatile Organic Compound (VOC) emissions and their impact on surface VOC and ozone concentrations in southeast Texas during September 2013. The model was evaluated against the ground-level Automated Gas Chromatograph (Auto-GC) measurement data from the Texas Commission on Environmental Quality (TCEQ). The comparisons indicated that the model over-predicted benzene, ethylene, toluene and xylene, while under-predicting isoprene and ethane. The mean biases between simulated and observed values of each VOC species showed clear daytime, nighttime, weekday and weekend variations. Adjusting the VOC emissions using simulated/observed ratios improved model performance of each VOC species, especially mitigating the mean bias substantially. Simulated monthly mean ozone showed a minor change: a 0.4 ppb or 1.2% increase; while a change of more than 5 ppb was seen in hourly ozone data on high ozone days, this change moved model predictions closer to observations. The CMAQ model run with the adjusted emissions better reproduced the variability in the National Aeronautics and Space Administration (NASA)'s Ozone Monitoring Instrument (OMI) formaldehyde (HCHO) columns. The adjusted model scenario also slightly better reproduced the aircraft HCHO concentrations from NASA's DISCOVER-AQ campaign conducted during the simulation episode period; Correlation, Mean Bias and RMSE improved from 0.34, 1.38 ppb and 2.15 ppb to 0.38, 1.33 ppb and 2.08 ppb respectively. A process analysis conducted for both industrial/urban and rural areas suggested that chemistry was the main process contributing to ozone production in both areas, while the impact of chemistry was smaller in rural areas than in industrial and urban areas. For both areas, the positive chemistry contribution increased in the sensitivity simulation largely due to the increase in emissions. Nudging VOC emissions to match the observed concentrations shifted the ozone hotspots

Sources of long-lived atmospheric VOCs at the rural boreal forest site, SMEAR II

Science.gov (United States)

Patokoski, J.; Ruuskanen, T. M.; Kajos, M. K.; Taipale, R.; Rantala, P.; Aalto, J.; Ryyppö, T.; Nieminen, T.; Hakola, H.; Rinne, J.

2015-12-01

In this study a long-term volatile organic compound (VOCs) concentration data set, measured at the SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations) boreal forest site in Hyytiälä, Finland during the years 2006-2011, was analyzed in order to identify source areas and profiles of the observed VOCs. VOC mixing ratios were measured using proton transfer reaction mass spectrometry. Four-day HYSPLIT 4 (Hybrid Single Particle Lagrangian Integrated Trajectory) backward trajectories and the Unmix 6.0 receptor model were used for source area and source composition analysis. Two major forest fire events in Russia took place during the measurement period. The effect of these fires was clearly visible in the trajectory analysis, lending confidence to the method employed with this data set. Elevated volume mixing ratios (VMRs) of non-biogenic VOCs related to forest fires, e.g. acetonitrile and aromatic VOCs, were observed. Ten major source areas for long-lived VOCs (methanol, acetonitrile, acetaldehyde, acetone, benzene, and toluene) observed at the SMEAR II site were identified. The main source areas for all the targeted VOCs were western Russia, northern Poland, Kaliningrad, and the Baltic countries. Industrial areas in northern continental Europe were also found to be source areas for certain VOCs. Both trajectory and receptor analysis showed that air masses from northern Fennoscandia were less polluted with respect to both the VOCs studied and other trace gases (CO, SO2 and NOx), compared to areas of eastern and western continental Europe, western Russia, and southern Fennoscandia.

Effect of traffic restriction on reducing ambient volatile organic compounds (VOCs): Observation-based evaluation during a traffic restriction drill in Guangzhou, China

Science.gov (United States)

Huang, Xinyu; Zhang, Yanli; Yang, Weiqiang; Huang, Zuzhao; Wang, Yujun; Zhang, Zhou; He, Quanfu; Lü, Sujun; Huang, Zhonghui; Bi, Xinhui; Wang, Xinming

2017-07-01

Traffic restriction (TR) is a widely adopted control measure in case of heavy air pollution particularly in urban areas, yet it is hard to evaluate the effect of TR on reducing VOC emissions based on monitoring data since ambient VOC mixing ratios are influenced not only by source emissions but also by meteorological conditions and atmospheric degradation. Here we collected air samples for analysis of VOCs before, during and after a TR drill carried out in Guangzhou in September 2010 at both a roadside and a rooftop (∼50 m above the ground) site. TR measures mainly included the "odd-even license" rule and banning high-emitting "yellow label" vehicles. The mixing ratios of non-methane hydrocarbons (NMHCs) did not show significant changes at the roadside site with total NMHCs of 39.0 ± 11.8 ppbv during non-TR period and 39.1 ± 14.8 ppbv during TR period, whereas total NMHCs decreased from 30.4 ± 14.3 ppbv during the non-TR period to 22.1 ± 10.6 ppbv during the TR period at rooftop site. However, the ratios of methyl tert-butyl ether (MTBE), benzene and toluene against carbon monoxide (MTBE/CO, T/CO and B/CO) at the both sampling sites dropped significantly. The ratios of toluene to benzene (T/B) instead increased significantly. Changes in these ratios all consistently indicated reduced input from traffic emissions particularly gasoline vehicles. Source attribution by positive matrix factorization (PMF) confirmed that during the TR period gasoline vehicles contributed less VOCs in percentages while industrial sources, biomass burning and LPG shared larger percentages. Assuming that emissions from industrial sources remained unchanged during the TR and non-TR periods, we further used the PMF-retrieved contribution percentages to deduce the reduction rate of traffic-related VOC emissions, and obtained a reduction rate of 31% based on monitoring data at the roadside site and of 34% based on the monitoring data at the rooftop site. Considering VOC emissions from all

Trends of VOC exposures among a nationally representative sample: Analysis of the NHANES 1988 through 2004 data sets

Science.gov (United States)

Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

2011-09-01

Exposures to volatile organic compounds (VOCs) are ubiquitous due to emissions from personal, commercial and industrial products, but quantitative and representative information regarding long term exposure trends is lacking. This study characterizes trends from 1988 to 2004 for the 15 VOCs measured in blood in five cohorts of the National Health and Nutrition Examination Survey (NHANES), a large and representative sample of U.S. adults. Trends were evaluated at various percentiles using linear quantile regression (QR) models, which were adjusted for solvent-related occupations and cotinine levels. Most VOCs showed decreasing trends at all quantiles, e.g., median exposures declined by 2.5 (m,p-xylene) to 6.4 (tetrachloroethene) percent per year over the 15 year period. Trends varied by VOC and quantile, and were grouped into three patterns: similar decreases at all quantiles (including benzene, toluene); most rapid decreases at upper quantiles (ethylbenzene, m,p-xylene, o-xylene, styrene, chloroform, tetrachloroethene); and fastest declines at central quantiles (1,4-dichlorobenzene). These patterns reflect changes in exposure sources, e.g., upper-percentile exposures may result mostly from occupational exposure, while lower percentile exposures arise from general environmental sources. Both VOC emissions aggregated at the national level and VOC concentrations measured in ambient air also have declined substantially over the study period and are supportive of the exposure trends, although the NHANES data suggest the importance of indoor sources and personal activities on VOC exposures. While piecewise QR models suggest that exposures of several VOCs decreased little or any during the 1990's, followed by more rapid decreases from 1999 to 2004, questions are raised concerning the reliability of VOC data in several of the NHANES cohorts and its applicability as an exposure indicator, as demonstrated by the modest correlation between VOC levels in blood and personal air

VOC emissions from residential combustion of Southern and mid-European woods

Science.gov (United States)

Evtyugina, Margarita; Alves, Célia; Calvo, Ana; Nunes, Teresa; Tarelho, Luís; Duarte, Márcio; Prozil, Sónia O.; Evtuguin, Dmitry V.; Pio, Casimiro

2014-02-01

Emissions of trace gases (carbon dioxide (CO2), carbon monoxide (CO), total hydrocarbons (THC)), and volatile organic compounds (VOCs) from combustion of European beech, Pyrenean oak and black poplar in a domestic woodstove and fireplace were studied. These woods are widely used as biofuel in residential combustion in Southern and mid-European countries. VOCs in the flue gases were collected in Tedlar bags, concentrated in sorbent tubes and analysed by thermal desorption-gas chromatography-flame ionisation detection (GC-FID). CO2 emissions ranged from 1415 ± 136 to 1879 ± 29 g kg-1 (dry basis). The highest emission factors for CO and THC, 115.8 ± 11.7 and 95.6 24.7 ± 6.3 g kg-1 (dry basis), respectively, were obtained during the combustion of black poplar in the fireplace. European beech presented the lowest CO and THC emission factors for both burning appliances. Significant differences in emissions of VOCs were observed among wood species burnt and combustion devices. In general the highest emission factors were obtained from the combustion of Pyrenean oak in the woodstove. Among the VOCs identified, benzene and related compounds were always the most abundant group, followed by oxygenated compounds and aliphatic hydrocarbons. The amount and the composition of emitted VOCs were strongly affected by the wood composition, the type of burning device and operating conditions. Emission data obtained in this work are useful for modelling the impact of residential wood combustion on air quality and tropospheric ozone formation.

Impact of a new gasoline benzene regulation on ambient air pollutants in Anchorage, Alaska

Science.gov (United States)

Yano, Yuriko; Morris, Stephen S.; Salerno, Christopher; Schlapia, Anne M.; Stichick, Mathew

2016-05-01

The purpose of this study was to quantify the impact of a new U.S. Environmental Protection Agency (EPA) standard that limits the amount of benzene allowed in gasoline on ambient benzene concentrations. This new standard, together with two companion regulations that limit cold-temperature automotive emissions and the permeability of portable fuel containers, was expected to lower the levels of ambient benzene and other volatile organic compounds (VOCs) nationwide. In this study the impact of the gasoline benzene standard was evaluated in Anchorage, Alaska in a two-phase ambient air monitoring study conducted before and after the new gasoline standard was implemented. Gasoline sold by Anchorage retailers was also evaluated in each phase to determine the content of benzene and other gasoline components. The average benzene content in Anchorage gasoline was reduced by 70%, from 5.05% (w/w) to 1.53% (w/w) following the implementation of the standard. The annual mean ambient benzene concentration fell by 51%, from 0.99 ppbv in Phase 1 to 0.49 ppbv in Phase 2. Analysis suggests the change in gasoline benzene content alone reduced benzene emissions by 46%. The changes in toluene, ethylbenzene, and xylene content in gasoline between Phase 1 and 2 were relatively small and the differences in the mean ambient concentrations of these compounds between phases were modest. Our results suggest that cold winter communities in high latitude and mountainous regions may benefit more from the gasoline benzene standard because of high benzene emissions resulting from vehicle cold start and a tendency to develop atmospheric stagnation conditions in the winter.

A Comparative study on VOCs and aldehyde-ketone emissions from a spark Ignition vehicle fuelled on compressed natural gas and gasoline

International Nuclear Information System (INIS)

Shah, A.N.

2012-01-01

In this work, an experimental study was conducted on a spark ignition (SI) vehicle fuelled on compressed natural gas (CNG), and gasoline to compare the unregulated emissions such as volatile organic compounds (VOCs) and aldehyde-ketones or carbonyls. In the meantime, ozone forming potential (OFP) of pollutants was also calculated on the basis of their specific reactivity (SR). The vehicle was run on a chassis dynamometer following the Chinese National Standards test scheduled for light duty vehicle (LDV) emissions. According to the results, total aldehyde-ketones were increased by 39.4% due to the substantial increase in formaldehyde and acrolein + acetone emissions, while VOCs and BTEX (benzene, toluene, ethyl benzene, and xylene) reduced by 85.2 and 86% respectively, in case of CNG fuelled vehicle as compared to gasoline vehicle. Although total aldehyde-ketones were higher with CNG relative to gasoline, their SR was lower due decrease in acetaldehyde, propionaldehyde, crotonaldehyde, and methacrolein species having higher maximum incremental reactivity (MIR) values. The SR of VOCs and aldehyde-ketones emitted from CNG fuelled vehicle was decreased by above 10% and 32% respectively, owing to better physicochemical properties and more complete burning of CNG as compared to gasoline. (author)

Chlorinated and Non chlorinated-Volatile Organic Compounds (Vocs) in Drinking Water of Peninsular Malaysia

International Nuclear Information System (INIS)

Mohd Pauzi Abdullah; Chian, S.S.

2011-01-01

A survey undertaken in Peninsular Malaysia has shown that volatile organic compounds (VOCs), both chlorinated and non-chlorinated, are present in selected drinking water samples. In this study, analyses of VOCs were performed by means of solid phase micro extraction (SPME) with a 100 μm polydimethylsiloxane (PDMS) fibre followed by gas chromatography - mass spectrometry detector (GC-MSD). Samples from different points of the distribution system networks were taken and analysed for 54 VOCs of different chemical families. The results of the study indicated that chloroform constituted the major portion of the VOCs in all samples analysed. In addition to trihalo methanes (THMs), other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene and 1,2-dichlorobenzene. However, the measured concentrations did not exceed the National Guideline for Drinking Water Quality 2000 in any case. No clear relationship between the status of development of a state in Malaysia to the levels and types of VOCs detected in its drinking water was noted. Nevertheless, the finding of anthropogenic chemicals, even at low concentrations, gave credibility to the viewpoint that improper development and disposal practices threatened the purity of the drinking water. (author)

Mineral-assisted production of benzene under hydrothermal conditions: Insights from experimental studies on C6 cyclic hydrocarbons

Science.gov (United States)

Venturi, Stefania; Tassi, Franco; Gould, Ian R.; Shock, Everett L.; Hartnett, Hilairy E.; Lorance, Edward D.; Bockisch, Christiana; Fecteau, Kristopher M.; Capecchiacci, Francesco; Vaselli, Orlando

2017-10-01

Volatile Organic Compounds (VOCs) are ubiquitously present at low but detectable concentrations in hydrothermal fluids from volcanic and geothermal systems. Although their behavior is strictly controlled by physical and chemical parameters, the mechanisms responsible for the production of most VOCs in natural environments are poorly understood. Among them, benzene, whose abundances were found to be relatively high in hydrothermal gases, can theoretically be originated from reversible catalytic reforming processes, i.e. multi-step dehydrogenation reactions, involving saturated hydrocarbons. However, this hypothesis and other hypotheses are difficult to definitively prove on the basis of compositional data obtained by natural gas discharges only. In this study, therefore, laboratory experiments were carried out to investigate the production of benzene from cyclic hydrocarbons at hydrothermal conditions, specifically 300 °C and 85 bar. The results of experiments carried out in the presence of water and selected powdered minerals, suggest that cyclohexane undergoes dehydrogenation to form benzene, with cyclohexene and cyclohexadiene as by-products, and also as likely reaction intermediates. This reaction is slow when carried out in water alone and competes with isomerization and hydration pathways. However, benzene formation was increased compared to these competing reactions in the presence of sulfide (sphalerite and pyrite) and iron oxide (magnetite and hematite) minerals, whereas no enhancement of any reaction products was observed in the presence of quartz. The production of thiols was observed in experiments involving sphalerite and pyrite, suggesting that sulfide minerals may act both to enhance reactivity and also as reactants after dissolution. These experiments demonstrate that benzene can be effectively produced at hydrothermal conditions through dehydrogenation of saturated cyclic organic structures and highlight the crucial role played by minerals in this

Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

Directory of Open Access Journals (Sweden)

Sung-Ok Baek

2015-08-01

Full Text Available This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory

Comparison of Benzene & Toluene removal from synthetic polluted air with use of Nano photocatalyticTiO2/ ZNO process.

Science.gov (United States)

Gholami, Mitra; Nassehinia, Hamid Reza; Jonidi-Jafari, Ahmad; Nasseri, Simin; Esrafili, Ali

2014-02-05

Mono aromatic hydrocarbons (BTEX) are a group of hazardous pollutants which originate from sources such as refineries, gas, and oil extraction fields, petrochemicals and paint and glue industries.Conventional methods, including incineration, condensation, adsorption and absorption have been used for removal of VOCs. None of these methods is economical for removal of pollutants of polluted air with low to moderate concentrations. The heterogeneous photocatalytic processes involve the chemical reactions to convert pollutant to carbon dioxide and water. The aim of this paper is a comparison of Benzene & Toluene removal from synthetic polluted air using a Nano photocatalytic TiO2/ ZNO process. The X-ray diffraction (XRD) patterns showed that Nano crystals of TiO2 and ZNO were in anatase and rutile phases. Toluene & benzene were decomposed by TiO2/ ZNO Nano photocatalyst and UV radiation. Kruskal-wallis Test demonstrated that there are significant differences (pvalue UV intensity and decreasing initial concentrations. Effect of TiO2/ZNO Nano photocatalyst on benzene is less than that on toluene. In this research, Toluene & benzene removal by TiO2/ZNO and UV followed first-order reactions.

Catalytic combustion for the elimination of methane, BTEX and other VOC : IV

International Nuclear Information System (INIS)

Hayes, R.E.; Wanke, S.E.

2008-01-01

Options for volatile organic compound combustion include homogeneous combustion (flaring) or catalytic combustion involving a flameless combustion process that uses a solid catalyst to promote the combustion reaction. This presentation discussed relative reactivity testing for volatile organic compounds (VOCs) over commercial catalysts. Several commercial pad catalysts were tested, as well as other powders. The relative reactivity of methane as well as benzene, toluene, ethylbenzene, and xylene (BTEX) were investigated. The purpose of the project was to evaluate combustion of concentrated methane streams that contained BTEX compounds; evaluate catalytic combustion using a counter diffusive radiant heater; develop mathematical models for the reactor to enhance design and understanding; improve the catalyst for BTEX combustion; and target application-dehydrator units. Topics that were addressed in the presentation included methane and benzene conversion; catalytic radiant heaters; small industrial and commercial units; measured temperature distribution; fuel slippage, methane conversion; the effect of water and hydrocarbons; the effect of water-liquid injection; and water addition as vapour. Several observations were offered, including that high percentages of injected liquid water can reduce reactor operating temperature; combustion of BTEX remained highly efficient, however liquid injection could also cause temperature reductions and ultimately the reactor would extinguish; and pre-heating the feed can eliminate the temperature drop and pad wetness problem. It was concluded that BTEX compounds are reactive, and the technology appears promising. 19 figs

Catalytic combustion for the elimination of methane, BTEX and other VOC : IV

Energy Technology Data Exchange (ETDEWEB)

Hayes, R.E.; Wanke, S.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

2008-07-01

Options for volatile organic compound combustion include homogeneous combustion (flaring) or catalytic combustion involving a flameless combustion process that uses a solid catalyst to promote the combustion reaction. This presentation discussed relative reactivity testing for volatile organic compounds (VOCs) over commercial catalysts. Several commercial pad catalysts were tested, as well as other powders. The relative reactivity of methane as well as benzene, toluene, ethylbenzene, and xylene (BTEX) were investigated. The purpose of the project was to evaluate combustion of concentrated methane streams that contained BTEX compounds; evaluate catalytic combustion using a counter diffusive radiant heater; develop mathematical models for the reactor to enhance design and understanding; improve the catalyst for BTEX combustion; and target application-dehydrator units. Topics that were addressed in the presentation included methane and benzene conversion; catalytic radiant heaters; small industrial and commercial units; measured temperature distribution; fuel slippage, methane conversion; the effect of water and hydrocarbons; the effect of water-liquid injection; and water addition as vapour. Several observations were offered, including that high percentages of injected liquid water can reduce reactor operating temperature; combustion of BTEX remained highly efficient, however liquid injection could also cause temperature reductions and ultimately the reactor would extinguish; and pre-heating the feed can eliminate the temperature drop and pad wetness problem. It was concluded that BTEX compounds are reactive, and the technology appears promising. 19 figs.

Benzene emission from the actual car fleet in relation to petrol composition in Denmark

International Nuclear Information System (INIS)

Palmgren, F.; Hansen, A.B.; Berkowicz, R.; Skov, H.

2001-01-01

The present study covers an investigation of the trends in air pollution levels of benzene in Danish cities and their relationship with the benzene content in petrol. Petrol samples from the two refineries in Denmark as well as sold petrol from some representative Danish petrol stations were analysed. The benzene content in Danish petrol was reduced from 3.5% for 95 octane prior to 1995 to approx. 2% in 1995 and further to 1% in 1998. Air quality measurements of aromatic VOC are available from two Danish cities; Copenhagen since 1994 and Odense since 1997. Measurements of benzene, CO and NO x from these two locations were analysed using the Operational Street Pollution Model (OSPM) and trends in the actual emissions of these pollutants were determined. It is shown that the decrease in both the concentration levels and in the emissions was significantly larger for benzene than for CO and NO x . The decreasing trends of NO x and CO could be explained by the increasing fraction of petrol-fuelled vehicles with three way catalysts (TWC). The much steeper decreasing trend for benzene can most likely be attributed to a combination of the effect of the increasing share of the TWC vehicles and a simultaneous reduction of benzene content in Danish petrol. The reduction of benzene concentrations and emissions is observed despite that the total amount of aromatics in petrol has increased slightly in the same period. (Author)

Occurrence and removal of volatile organic compounds (VOC) relative to water treatment plants in Malaysia

International Nuclear Information System (INIS)

Soh Shiau Chian

2005-01-01

A solid phase micro extraction technique with determination analysis by gas chromatography and mass spectrometry detector (SPME-GC-MSD) to determine 54 volatile organic compounds (VOC) in drinking water was successfully developed. The optimal conditions lead to mean recoveries of 85 % with the relative standard deviation below 13 %. Limit of detection was ranged from 0.005 μg/ l to 1.121 μg/ l for all VOC. Upon consideration of the complete procedure from sample preparation to instrumental determination, the expanded uncertainty for all VOC under study was in the range of 1.056 to 2.952 μg/ l. The optimised SPME-GC-MSD method was used to determine distributions and occurence of VOC in drinking water for Peninsular Malaysia for one year and a specific study carried out in Semenyih Catchment and Semenyih River Water Treatment Plant. Results from the monitoring programme showed that concentration of VOC ranged from undetectable to 190.9 μg/ l. Chloroform has the highest concentration and was detected in all drinking water samples. Apart from trihalomethanes (THM), other abundant compounds detected were 1,2-dibromoethane, cis and trans-1,3-dichloropropene, 1,2,3-trichloropropane and benzene. This indicated the presence of VOC in drinking water and thus is required to be frequently monitored in order to ensure and maintain drinking water quality. Based on exposure risks assessment, results from this study showed that total cancer risks was the greatest for benzene, followed by 1,2-dibromo-3-chloropropane, 1,2-dibromomethane, chloroform and dichlorobromomethane. Nevertheless, after considering the frequency of detection factor and alteration of cancer risks that has been done, chloroform contributed the highest cancer risks among other VOC compounds. On a specific study in Semenyih Catchment, the declination of water quality in Semenyih River between 1990 and 2004 to a perturbing stage was due to urbanisation process and industrial growth. Apart from raw water

Characterization of VOCs Across Pennsylvania: Assessing Emissions from Rural, Forested, Agricultural and Natural Gas Drilling-Impacted Areas

Science.gov (United States)

Grannas, A. M.; Fuentes, J. D.; Ramos-Garcés, F.; Wang, D. K.; Martins, D. K.

2012-12-01

Volatile organic compounds (VOCs) of both biogenic and anthropogenic origin are important to troposphere chemistry, particularly the formation of photochemical smog and secondary organic aerosol. There is concern that increased natural gas exploration may lead to increased emissions of certain VOCs during well development and due to fugitive emissions from operational well sites and pipelines. For a six-day period in June 2012, a variety of VOCs were measured using canister sampling from a mobile measurement platform. Transects from southwestern to northeastern Pennsylvania were studied, with samples obtained in rural, forested, urban, farm-impacted and gas well-impacted sites. As expected, biogenic VOCs and isoprene oxidation products were enhanced in forested regions, while anthropogenic non-methane hydrocarbons were enhanced in urban areas. BTEX (benzene, toluene, ethylbenzene and xylenes) was enhanced in urban areas, but the concentrations of BTEX measured near developing and existing natural gas sites were similar to rural and forested sites. Halogenated hydrocarbons and Freon compounds were consistent at all site locations. We will discuss the specific concentrations and signatures of these compounds and assess the potential impact of agricultural activities and gas well development on the observed VOC concentrations and variability.

Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley

Science.gov (United States)

Sarkar, Chinmoy; Sinha, Vinayak; Kumar, Vinod; Rupakheti, Maheswar; Panday, Arnico; Mahata, Khadak S.; Rupakheti, Dipesh; Kathayat, Bhogendra; Lawrence, Mark G.

2016-03-01

The Kathmandu Valley in Nepal suffers from severe wintertime air pollution. Volatile organic compounds (VOCs) are key constituents of air pollution, though their specific role in the valley is poorly understood due to insufficient data. During the SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley-Atmospheric Brown Clouds) field campaign conducted in Nepal in the winter of 2012-2013, a comprehensive study was carried out to characterise the chemical composition of ambient Kathmandu air, including the determination of speciated VOCs, by deploying a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) - the first such deployment in South Asia. In the study, 71 ion peaks (for which measured ambient concentrations exceeded the 2σ detection limit) were detected in the PTR-TOF-MS mass scan data, highlighting the chemical complexity of ambient air in the valley. Of the 71 species, 37 were found to have campaign average concentrations greater than 200 ppt and were identified based on their spectral characteristics, ambient diel profiles and correlation with specific emission tracers as a result of the high mass resolution (m / Δm > 4200) and temporal resolution (1 min) of the PTR-TOF-MS. The concentration ranking in the average VOC mixing ratios during our wintertime deployment was acetaldehyde (8.8 ppb) > methanol (7.4 ppb) > acetone + propanal (4.2 ppb) > benzene (2.7 ppb) > toluene (1.5 ppb) > isoprene (1.1 ppb) > acetonitrile (1.1 ppb) > C8-aromatics ( ˜ 1 ppb) > furan ( ˜ 0.5 ppb) > C9-aromatics (0.4 ppb). Distinct diel profiles were observed for the nominal isobaric compounds isoprene (m / z = 69.070) and furan (m / z = 69.033). Comparison with wintertime measurements from several locations elsewhere in the world showed mixing ratios of acetaldehyde ( ˜ 9 ppb), acetonitrile ( ˜ 1 ppb) and isoprene ( ˜ 1 ppb) to be among the highest reported to date. Two "new" ambient compounds, namely formamide (m / z = 46.029) and acetamide (m / z

Benzene from Traffic

DEFF Research Database (Denmark)

Palmgren, F.; Berkowicz, R.; Skov, H.

The measurements of benzene showed very clear decreasing trends in the air concentrations and the emissions since 1994. At the same time the measurements of CO and NOx also showed a decreasing trend, but not so strong as for benzene. The general decreasing trend is explained by the increasing...... number of petrol vehicles with three way catalysts, 60-70% in 1999. The very steep decreasing trend for benzene at the beginning of the period from 1994 was explained by the combination of more catalyst vehicles and reduced benzene content in Danish petrol. The total amount of aromatics in petrol......, including toluene, increased only weakly. The analyses of air concentrations were confirmed by analyses of petrol sold in Denmark. The concentration of benzene at Jagtvej in Copenhagen is still in 1998 above the expected new EU limit value, 5 µg/m3 as annual average. However, the reduced content of benzene...

Aromatic VOCs global influence in the ozone production

Science.gov (United States)

Cabrera-Perez, David; Pozzer, Andrea

2016-04-01

Aromatic hydrocarbons are a subgroup of Volatile Organic Compounds (VOCs) of special interest in the atmosphere of urban and semi-urban areas. Aromatics form a high fraction of VOCs, are highly reactive and upon oxidation they are an important source of ozone. These group of VOCs are released to the atmosphere by processes related to biomass burning and fossil fuel consumption, while they are removed from the atmosphere primarily by OH reaction and by dry deposition. In addition, a branch of aromatics (ortho-nitrophenols) produce HONO upon photolysis, which is responsible of certain amount of the OH recycling. Despite their importance in the atmosphere in anthropogenic polluted areas, the influence of aromatics in the ozone production remains largely unknown. This is of particular relevance, being ozone a pollutant with severe side effects on air quality, health and climate. In this work the atmospheric impacts at global scale of the most emitted aromatic VOCs in the gas phase (benzene, toluene, xylenes, ethylbenzene, styrene, phenol, benzaldehyde and trimethylbenzenes) are analysed and assessed. Specifically, the impact on ozone due to aromatic oxidation is estimated, as this is of great interest in large urban areas and can be helpful for developing air pollution control strategies. Further targets are the quantification of the NOx loss and the OH recycling due to aromatic oxidation. In order to investigate these processes, two simulations were performed with the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations compare two cases, one with ozone concentrations when aromatics are present or the second one when they are missing. Finally, model simulated ozone is compared against a global set of observations in order to better constrain the model accuracy.

Assessment of Exposure to VOCs among Pregnant Women in the National Children's Study.

Science.gov (United States)

Boyle, Elizabeth Barksdale; Viet, Susan M; Wright, David J; Merrill, Lori S; Alwis, K Udeni; Blount, Benjamin C; Mortensen, Mary E; Moye, John; Dellarco, Michael

2016-03-29

Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children's Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N

Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

DEFF Research Database (Denmark)

Emmerling, Uwe; Rasmussen, Peter

1998-01-01

a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC......Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...

PARTITIONING OF BENZENE IN SICKLE CELL BLOOD AND NORMAL BLOOD AND IN THE BLOOD OF THE GUINEA PIG, MOUSE, AND RAT

Science.gov (United States)

AbstractBenzene was used as a prototypic volatile organic chemical to ascertain whether the insoluble form of hemoglobin (HbS) from subjects with homozygous sickle cell disease (SCD) has a greater VOC carrying capacity than hemoglobin (Hb) from normal subjects (HbA) which is ...

Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

Directory of Open Access Journals (Sweden)

C. Huang

2011-05-01

Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO₂, NO_x, CO, PM₁₀, PM_2.5, VOCs, and NH₃ in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO₂, NO_x, PM₁₀, PM_2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NO_x and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.

Solid phase microextraction: measurement of volatile organic compounds (VOCs) in Dhaka City air pollution.

Science.gov (United States)

Hussam, A; Alauddin, M; Khan, A H; Chowdhury, D; Bibi, H; Bhattacharjee, M; Sultana, S

2002-08-01

A solid phase microextraction (SPME) technique was applied for the sampling of volatile organic compounds (VOCs) in ambient air polluted by two stroke autorickshaw engines and automobile exhausts in Dhaka city, Bangladesh. Analysis was carried out by capillary gas chromatography (GC) and GC-mass spectrometry (MS). The methodology was tested by insitu sampling of an aromatic hydrocarbon mixture gas standard with a precision of +/-5% and an average accuracy of 1-20%. The accuracy for total VOCs concentration measurement was about 7%. VOC's in ambient air were collected by exposing the SPME fiber at four locations in Dhaka city. The chromatograms showed signature similar to that of unburned gasoline (petrol) and weathered diesel containing more than 200 organic compounds; some of these compounds were positively identified. These are normal hydrocarbons pentane (n-C5H2) through nonacosane (n-C29H60), aromatic hydrocarbons: benzene, toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, 1,3,5-trimethylbenzene, xylenes, and 1-isocyanato-3-methoxybenzene. Two samples collected near an autorickshaw station contained 783000 and 1479000 microg/m3 of VOCs. In particular, the concentration of toluene was 50-100 times higher than the threshold limiting value of 2000 microg/m3. Two other samples collected on street median showed 135000 microg/m3 and 180000 microg/m3 of total VOCs. The method detection limit of the technique for most semi-volatile organic compounds was 1 microg/m3.

Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

Directory of Open Access Journals (Sweden)

Elizabeth Barksdale Boyle

2016-03-01

Full Text Available Epidemiologic studies can measure exposure to volatile organic compounds (VOCs using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS. We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking and by observations by a trained data collector (presence of scented products in homes. We found several significant (p < 0.01 relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite

Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

Science.gov (United States)

Boyle, Elizabeth Barksdale; Viet, Susan M.; Wright, David J.; Merrill, Lori S.; Alwis, K. Udeni; Blount, Benjamin C.; Mortensen, Mary E.; Moye, John; Dellarco, Michael

2016-01-01

Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N

Suns-VOC characteristics of high performance kesterite solar cells

Science.gov (United States)

Gunawan, Oki; Gokmen, Tayfun; Mitzi, David B.

2014-08-01

Low open circuit voltage (VOC) has been recognized as the number one problem in the current generation of Cu2ZnSn(Se,S)4 (CZTSSe) solar cells. We report high light intensity and low temperature Suns-VOC measurement in high performance CZTSSe devices. The Suns-VOC curves exhibit bending at high light intensity, which points to several prospective VOC limiting mechanisms that could impact the VOC, even at 1 sun for lower performing samples. These VOC limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects, including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-VOC measurements with different monochromatic illuminations. These limiting factors may also contribute to an artificially lower JSC-VOC diode ideality factor.

Diurnally resolved particulate and VOC measurements at a rural site: indication of significant biogenic secondary organic aerosol formation

Science.gov (United States)

Sjostedt, S. J.; Slowik, J. G.; Brook, J. R.; Chang, R. Y.-W.; Mihele, C.; Stroud, C. A.; Vlasenko, A.; Abbatt, J. P. D.

2011-06-01

We report simultaneous measurements of volatile organic compound (VOC) mixing ratios including C6 to C8 aromatics, isoprene, monoterpenes, acetone and organic aerosol mass loadings at a rural location in southwestern Ontario, Canada by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and Aerosol Mass Spectrometry (AMS), respectively. During the three-week-long Border Air Quality and Meteorology Study in June-July 2007, air was sampled from a range of sources, including aged air from the polluted US Midwest, direct outflow from Detroit 50 km away, and clean air with higher biogenic input. After normalization to the diurnal profile of CO, a long-lived tracer, diurnal analyses show clear photochemical loss of reactive aromatics and production of oxygenated VOCs and secondary organic aerosol (SOA) during the daytime. Biogenic VOC mixing ratios increase during the daytime in accord with their light- and temperature-dependent sources. Long-lived species, such as hydrocarbon-like organic aerosol and benzene show little to no photochemical reactivity on this timescale. From the normalized diurnal profiles of VOCs, an estimate of OH concentrations during the daytime, measured O3 concentrations, and laboratory SOA yields, we calculate integrated local organic aerosol production amounts associated with each measured SOA precursor. Under the assumption that biogenic precursors are uniformly distributed across the southwestern Ontario location, we conclude that such precursors contribute significantly to the total amount of SOA formation, even during the period of Detroit outflow. The importance of aromatic precursors is more difficult to assess given that their sources are likely to be localized and thus of variable impact at the sampling location.

Fine platinum nanoparticles supported on a porous ceramic membrane as efficient catalysts for the removal of benzene.

Science.gov (United States)

Liu, Hui; Li, Chengyin; Ren, Xiaoyong; Liu, Kaiqi; Yang, Jun

2017-11-29

It would be desirable to remove volatile organic compounds (VOCs) while we eliminate the dusts using silicon carbide (SiC)-based porous ceramics from the hot gases. Aiming at functionalizing SiC-based porous ceramics with catalytic capability, we herein report a facile strategy to integrate high efficient catalysts into the porous SiC substrates for the VOC removal. We demonstrate an aqueous salt method for uniformly distributing fine platinum (Pt) particles on the alumina (Al 2 O 3 ) layers, which are pre-coated on the SiC substrates as supports for VOC catalysts. We confirm that at a Pt mass loading as low as 0.176% and a weight hourly space velocity of 6000 mL g -1 h -1 , the as-prepared Pt/SiC@Al 2 O 3 catalysts can convert 90% benzene at a temperature of ca. 215 °C. The results suggest a promising way to design ceramics-based bi-functional materials for simultaneously eliminating dusts and harmful VOCs from various hot gases.

Characterizing relationships between personal exposures to VOCs and socioeconomic, demographic, behavioral variables

Science.gov (United States)

Wang, Sheng-Wei; Majeed, Mohammed A.; Chu, Pei-Ling; Lin, Hui-Chih

Socioeconomic and demographic factors have been found to significantly affect time-activity patterns in population cohorts that can subsequently influence personal exposures to air pollutants. This study investigates relationships between personal exposures to eight VOCs (benzene, toluene, ethylbenzene, o-xylene, m-,p-xylene, chloroform, 1,4-dichlorobenzene, and tetrachloroethene) and socioeconomic, demographic, time-activity pattern factors using data collected from the 1999-2000 National Health and Nutrition Examination Survey (NHANES) VOC study. Socio-demographic factors (such as race/ethnicity and family income) were generally found to significantly influence personal exposures to the three chlorinated compounds. This was mainly due to the associations paired by race/ethnicity and urban residence, race/ethnicity and use of air freshener in car, family income and use of dry-cleaner, which can in turn affect exposures to chloroform, 1,4-dichlorobenzene, and tetrachloroethene, respectively. For BTEX, the traffic-related compounds, housing characteristics (leaving home windows open and having an attached garage) and personal activities related to the uses of fuels or solvent-related products played more significant roles in influencing exposures. Significant differences in BTEX exposures were also commonly found in relation to gender, due to associated significant differences in time spent at work/school and outdoors. The coupling of Classification and Regression Tree (CART) and Bootstrap Aggregating (Bagging) techniques were used as effective tools for characterizing robust sets of significant VOC exposure factors presented above, which conventional statistical approaches could not accomplish. Identification of these significant VOC exposure factors can be used to generate hypotheses for future investigations about possible significant VOC exposure sources and pathways in the general U.S. population.

Temporal variation of VOC emission from solvent and water based wood stains

Science.gov (United States)

de Gennaro, Gianluigi; Loiotile, Annamaria Demarinis; Fracchiolla, Roberta; Palmisani, Jolanda; Saracino, Maria Rosaria; Tutino, Maria

2015-08-01

Solvent- and water-based wood stains were monitored using a small test emission chamber in order to characterize their emission profiles in terms of Total and individual VOCs. The study of concentration-time profiles of individual VOCs enabled to identify the compounds emitted at higher concentration for each type of stain, to examine their decay curve and finally to estimate the concentration in a reference room. The solvent-based wood stain was characterized by the highest Total VOCs emission level (5.7 mg/m3) that decreased over time more slowly than those related to water-based ones. The same finding was observed for the main detected compounds: Benzene, Toluene, Ethylbenzene, Xylenes, Styrene, alpha-Pinene and Camphene. On the other hand, the highest level of Limonene was emitted by a water-based wood stain. However, the concentration-time profile showed that water-based product was characterized by a remarkable reduction of the time of maximum and minimum emission: Limonene concentration reached the minimum concentration in about half the time compared to the solvent-based product. According to AgBB evaluation scheme, only one of the investigated water-based wood stains can be classified as a low-emitting product whose use may not determine any potential adverse effect on human health.

Modeling VOC transport in simulated waste drums

International Nuclear Information System (INIS)

Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

1993-06-01

A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the VOC permeability had been measured. Permeabilities for five VOCs [methylene chloride, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), 1,1,1-trichloroethane, carbon tetrachloride, and trichloroethylene] were measured across a polyethylene bag. Comparison of model and experimental results of VOC concentration as a function of time indicate that model accurately accounts for significant VOC transport mechanisms in a lab-scale waste drum

Sensitive and selective system of benzene detection based on a cataluminescence sensor.

Science.gov (United States)

Li, Bo; Zhang, Yuejin; Liu, Juefu; Xie, Xin; Zou, Dan; Li, Minqiang; Liu, Jinhuai

2014-06-01

Au/La2 O3 nanomaterials were prepared through calcining Au-modified La(OH)3 precursors. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD) were employed to characterize the as-prepared samples. Benzene, a common volatile organic compound, was selected as a model to investigate the cataluminescence (CTL)-sensing properties of the Au/La2 O3 nanomaterials. Results indicated that the as-prepared Au/La2 O3 exhibited outstanding CTL properties such as stable intensity, high signal-to-noise values, and short response and recovery times. Under optimized conditions, the benzene assay exhibited a broad linear range of 1-4000 ppm, with a limit of detection of 0.7 ppm, which was below the standard permitted concentrations. Furthermore, the gas sensor system showed outstanding selectivity for benzene compared with seven other types of common volatile organic compounds (VOCs). The proposed gas sensor showed good characteristics with high selectivity, fast response time and long lifetime, which suggested the promising application of the Au/La2 O3 nanomaterials as a novel highly efficient CTL-sensing material. Copyright © 2013 John Wiley & Sons, Ltd.

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride Tedlar® bags.

Science.gov (United States)

Kim, Yong-Hyun; Kim, Ki-Hyun; Jo, Sang-Hee; Jeon, Eui-Chan; Sohn, Jong Ryeul; Parker, David B

2012-01-27

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar(®)) bags for gaseous VOC sampling. Eight VOC standards (benzene, toluene, p-xylene, styrene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) were placed into each bag at storage times of 0, 2, and 3 days prior to analyses by gas chromatography/mass spectrometry (GC/MS). From each bag representing each storage day, samples of 3 different mass loadings were withdrawn and analyzed to derive response factors (RF) of each chemical between the slope of the GC response (y-axis) vs. loaded mass (x-axis). The relative recoveries (RR) of VOC, if derived by dividing RF value of a given storage day by that of 0 day, varied by time, bag type, and VOC type. If the RR values after three days are compared, those of methyl isobutyl ketone were the highest with 96 (PVF) and 99% (PEA); however, the results of isobutyl alcohol were highly contrasting between the two bags with 31 and 94%, respectively. Differences in RR values between the two bag types increased with storage time, such that RR of PEA bags (88±10%) were superior to those of PVF bags (73±22%) after three days, demonstrating that VOC in PEA bags were more stable than in PVF bags. Copyright © 2011 Elsevier B.V. All rights reserved.

Review of Portable and Low-Cost Sensors for the Ambient Air Monitoring of Benzene and Other Volatile Organic Compounds.

Science.gov (United States)

Spinelle, Laurent; Gerboles, Michel; Kok, Gertjan; Persijn, Stefan; Sauerwald, Tilman

2017-06-28

This article presents a literature review of sensors for the monitoring of benzene in ambient air and other volatile organic compounds. Combined with information provided by stakeholders, manufacturers and literature, the review considers commercially available sensors, including PID-based sensors, semiconductor (resistive gas sensors) and portable on-line measuring devices as for example sensor arrays. The bibliographic collection includes the following topics: sensor description, field of application at fixed sites, indoor and ambient air monitoring, range of concentration levels and limit of detection in air, model descriptions of the phenomena involved in the sensor detection process, gaseous interference selectivity of sensors in complex VOC matrix, validation data in lab experiments and under field conditions.

Emissions of volatile organic compounds (VOCs) from oil and natural gas activities: compositional comparison of 13 major shale basins via NOAA airborne measurements

Science.gov (United States)

Gilman, J.; Lerner, B. M.; Aikin, K. C.; De Gouw, J. A.; Koss, A.; Yuan, B.; Warneke, C.; Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Graus, M.; Tokarek, T. W.; Isaacman-VanWertz, G. A.; Sueper, D.; Worsnop, D. R.

2015-12-01

The recent and unprecedented increase in natural gas production from shale formations is associated with a rise in the production of non-methane volatile organic compounds (VOCs) including natural gas plant liquids (e.g., ethane, propane, and butanes) and liquid lease condensate (e.g., pentanes, hexanes, aromatics and cycloalkanes). Since 2010, the production of natural gas liquids and the amount of natural gas vented/flared has increased by factors of ~1.28 and 1.57, respectively (U.S. Energy and Information Administration), indicating an increasingly large potential source of hydrocarbons to the atmosphere. Emission of VOCs may affect local and regional air quality due to the potential to form tropospheric ozone and organic particles as well as from the release of toxic species such as benzene and toluene. The 2015 Shale Oil and Natural Gas Nexus (SONGNex) campaign studied emissions from oil and natural gas activities across the central United States in order to better understand their potential air quality and climate impacts. Here we present VOC measurements from 19 research flights aboard the NOAA WP-3D over 11 shale basins across 8 states. Non-methane hydrocarbons were measured using an improved whole air sampler (iWAS) with post-flight analysis via a custom-built gas chromatograph-mass spectrometer (GC-MS). The whole air samples are complimented by higher-time resolution measurements of methane (Picarro spectrometer), ethane (Aerodyne spectrometer), and VOCs (H3O+ chemical ionization mass spectrometer). Preliminary analysis show that the Permian Basin on the New Mexico/Texas border had the highest observed VOC mixing ratios for all basins studied. We will utilize VOC enhancement ratios to compare the composition of methane and VOC emissions for each basin and the associated reactivities of these gases with the hydroxyl radical, OH, as a proxy for potential ozone formation.

Secondary organic aerosol formation through cloud processing of aromatic VOCs

Science.gov (United States)

Herckes, P.; Hutchings, J. W.; Ervens, B.

2010-12-01

Field observations have shown substantial concentrations (20-5,500 ng L-1) of aromatic volatile organic compounds (VOC) in cloud droplets. The potential generation of secondary organic aerosol mass through the processing of these anthropogenic VOCs was investigated through laboratory and modeling studies. Under simulated atmospheric laboratory conditions, in idealized solutions, benzene, toluene, ethylbenzene, and xylene (BTEX) degraded quickly in the aqueous phase. The degradation process yielded less volatile products which would contribute to new aerosol mass upon cloud evaporation. However, when realistic cloud solutions containing natural organic matter were used in the experiments, the reaction rates decreased with increasing organic carbon content. Kinetic data derived from these experiments were used as input to a multiphase box model in order to evaluate the secondary organic aerosol (SOA) mass formation potential of cloud processing of BTEX. Model results will be presented that quantify the SOA amounts from these aqueous phase pathways. The efficiency of this multiphase SOA source will be compared to SOA yields from the same aromatics as treated in traditional SOA models that are restricted to gas phase oxidation and subsequent condensation on particles.

[Studies of ozone formation potentials for benzene and ethylbenzene using a smog chamber and model simulation].

Science.gov (United States)

Jia, Long; Xu, Yong-Fu

2014-02-01

Ozone formation potentials from irradiations of benzene-NO(x) and ethylbenzene-NO(x) systems under the conditions of different VOC/NO(x) ratios and RH were investigated using a characterized chamber and model simulation. The repeatability of the smog chamber experiment shows that for two sets of ethylbenzene-NO(x) irradiations with similar initial concentrations and reaction conditions, such as temperature, relative humidity and relative light intensity, the largest difference in O3 between two experiments is only 4% during the whole experimental run. On the basis of smog chamber experiments, ozone formation of photo-oxidation of benzene and ethylbenzene was simulated in terms of the master chemical mechanism (MCM). The peak ozone values for benzene and ethylbenzene simulated by MCM are higher than the chamber data, and the difference between the MCM-simulated results and chamber data increases with increasing RH. Under the conditions of sunlight irradiations, with benzene and ethylbenzene concentrations being in the range of (10-50) x 10(-9) and NO(x) concentrations in the range of (10-100) x 10(-9), the 6 h ozone contributions of benzene and ethylbenzene were obtained to be (3.1-33) x 10(-9) and (2.6-122) x 10(-9), whereas the peak O3 contributions of benzene and ethylbenzene were (3.5-54) x 10(-9) and (3.8-164) x 10(-9), respectively. The MCM-simulated maximum incremental reactivity (MIR) values for benzene and ethylbenzene were 0.25/C and 0.97/C (per carbon), respectively. The maximum ozone reactivity (MOR) values for these two species were obtained to be 0.73/C and 1.03/C, respectively. The MOR value of benzene from MCM is much higher than that obtained by carter from SAPRC, indicating that SAPRC may underestimate the ozone formation potential of benzene.

Comparison of VOC measurements made by PTR-MS, adsorbent tubes-GC-FID-MS and DNPH derivatization-HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

Science.gov (United States)

Dunne, Erin; Galbally, Ian E.; Cheng, Min; Selleck, Paul; Molloy, Suzie B.; Lawson, Sarah J.

2018-01-01

Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC) measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH-HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography) during routine monitoring as part of the Sydney Particle Study (SPS) campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75-0.98) and small root mean square of the deviations (RMSD) of the observations from the regression line with a median of 0.11 (range 0.04-0.23 ppbv). These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA) regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16-2.01. The intercepts varied with a median of 0.04 and a range of -0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for benzene, toluene and isoprene by

Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

International Nuclear Information System (INIS)

Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F.

1990-01-01

Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

Screening the Emission Sources of Volatile Organic Compounds (VOCs) in China Based on Multi-effect Evaluation

Science.gov (United States)

Niu, H., Jr.

2015-12-01

Volatile organic compounds (VOCs) in the atmosphere have adverse impacts via three main pathways: photochemical ozone formation, secondary organic aerosol production, and direct toxicity to humans. Few studies have integrated these effects to prioritize control measures for VOCs sources. In this study, we developed a multi-effect evaluation methodology based on updated emission inventories and source profiles, which was combined with ozone formation potential (OFP), secondary organic aerosol potential (SOAP), and VOC toxicity data to identify important emission sources and key species. We derived species-specific emission inventories for 152 sources. The OFPs, SOAPs, and toxicity of each source were determined, and the contribution and share of each source to each of these adverse effects was calculated. Weightings were given to the three adverse effects by expert scoring, and the integrated impact was determined. Using 2012 as the base year, solvent usage and industrial process were found to be the most important anthropogenic sources, accounting for 24.2 and 23.1% of the integrated environmental effect, respectively. This was followed by biomass burning, transportation, and fossil fuel combustion, all of which had a similar contribution ranging from 16.7 to 18.6%. The top five industrial sources, including plastic products, rubber products, chemical fiber products, the chemical industry, and oil refining, accounted for nearly 70.0% of industrial emissions. In China, emissions reductions are required for styrene, toluene, ethylene, benzene, and m/p-xylene. The 10 most abundant chemical species contributed 76.5% of the integrated impact. Beijing, Chongqing, Shanghai, Jiangsu, and Guangdong were the five leading provinces when considering the integrated effects. Besides, the chemical mass balance model (CMB) was used to verify the VOCs inventories of 47 cities in China, so as to optimize our evaluation results. We suggest that multi-effect evaluation is necessary to

Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

Directory of Open Access Journals (Sweden)

E. Dunne

2018-01-01

Full Text Available Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH–HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography during routine monitoring as part of the Sydney Particle Study (SPS campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75–0.98 and small root mean square of the deviations (RMSD of the observations from the regression line with a median of 0.11 (range 0.04–0.23 ppbv. These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16–2.01. The intercepts varied with a median of 0.04 and a range of −0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for

Benzene and its Isomers

Indian Academy of Sciences (India)

instantly brings benzene to mind. Benzene is one of the most basic structural units of thousands of the so-called aromatic compounds, which include dyes, drugs, polymers and many more types of compounds that are very useful for our existence and progress. The whole gamut of the chemistry of aromatic compounds, ...

Indoor Air Quality Assessment and Study of Different VOC Contributions within a School in Taranto City, South of Italy

Directory of Open Access Journals (Sweden)

Annalisa Marzocca

2017-03-01

Full Text Available Children spend a large amount of time in school environments and when Indoor Air Quality (IAQ is poor, comfort, productivity and learning performances may be affected. The aim of the present study is to characterize IAQ in a primary school located in Taranto city (south of Italy. Because of the proximity of a large industrial complex to the urban settlement, this district is one of the areas identified as being at high environmental risk in Italy. The study carried out simultaneous monitoring of indoor and outdoor Volatile Organic Compounds (VOC concentrations and assessed different pollutants’ contributions on the IAQ of the investigated site. A screening study of VOC and determination of Benzene, Toluene, Ethylbenzene, Xylenes (BTEX, sampled with Radiello® diffusive samplers suitable for thermal desorption, were carried out in three classrooms, in the corridor and in the yard of the school building. Simultaneously, Total VOC (TVOC concentration was measured by means of real-time monitoring, in order to study the activation of sources during the monitored days. The analysis results showed a prevalent indoor contribution for all VOC except for BTEX which presented similar concentrations in indoor and outdoor air. Among the determined VOC, Terpenes and 2-butohxyethanol were shown to be an indoor source, the latter being the indoor pollutant with the highest concentration.

Measurement of VOC permeability of polymer bags and VOC solubility in polyethylene drum liner

International Nuclear Information System (INIS)

Liekhus, K.J.; Peterson, E.S.

1995-03-01

A test program conducted at the Idaho National Engineering Laboratory (INEL) investigated the use of a transport model to estimate the volatile organic compound (VOC) concentration in the void volume of a waste drum. Unsteady-state VOC transport model equations account for VOC permeation of polymer bags, VOC diffusion across openings in layers of confinement, and VOC solubility in a polyethylene drum liner. In support of this program, the VOC permeability of polymer bags and VOC equilibrium concentration in a polyethylene drum liner were measured for nine VOCs. The VOCs used in experiments were dichloromethane, carbon tetrachloride, cyclohexane, toluene, 1,1,1-trichloroethane, methanol, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), trichloroethylene, and p-xylene. The experimental results of these measurements as well as a method of estimating both parameters in the absence of experimental data are described in this report

Assessing the sensitivity of benzene cluster cation chemical ionization mass spectrometry toward a wide array of biogenic volatile organic compounds

Science.gov (United States)

Lavi, Avi; Vermeuel, Michael; Novak, Gordon; Bertram, Timothy

2017-04-01

Chemical ionization mass spectrometry is a real-time, sensitive and selective measurement technique for the detection of volatile organic compounds (VOCs). The benefits of CIMS technology make it highly suitable for field measurements that requires fast (10Hz and higher) response rates, such as the study of surface-atmosphere exchange processes by the eddy covariance method. The use of benzene cluster cations as a regent ion was previously demonstrated as a sensitive and selective method for the detection of select biogenic VOCs (e.g. isoprene, monoterpenes and sesquiterpenes) [Kim et al., 2016; Leibrock and Huey, 2000]. Quantitative analysis of atmospheric trace gases necessitates calibration for each analyte as a function of atmospheric conditions. We describe a custom designed calibration system, based on liquid evaporation, for determination of the sensitivity of the benzene-CIMS to a wide range of organic compounds at atmospherically relevant mixing ratios (volatile organic compounds, Atmos Meas Tech, 9(4), 1473-1484, doi:10.5194/amt-9-1473-2016. Leibrock, E., and L. G. Huey (2000), Ion chemistry for the detection of isoprene and other volatile organic compounds in ambient air, Geophys Res Lett, 27(12), 1719-1722, doi:Doi 10.1029/1999gl010804.

Detection of new VOC compounds with iCRDS

Science.gov (United States)

Huang, H.; Leen, J. B.; Gardner, A.; Gupta, M.; Baer, D. S.

2015-12-01

The instrument at Los Gatos Research (a member of ABB Inc.) which is based on incoherent cavity ringdown spectroscopy (iCRDS) that operates in the mid-infrared (bands from 860-1060 cm-1 or 970-1280 cm-1) is capable of detecting a broad range of VOCs, in situ, continuously and autonomously, for example, BTEX compounds (benzene, toluene, ethylbenzene, xylene), including differentiation of xylene isomers. Previously, we have demonstrated the measurement of trichloroethylene (TCE) in zero air with a precision of 0.17 ppb (1σ in 4 minutes), and the measurement of tetrachloroethylene (PCE) with a precision of 0.15 ppb (1σ in 4 minutes). Both of these measured precisions exceed the EPA's commercial building action limit, which for TCE is 0.92 ppb (5 µg/m3) and for PCE is 0.29 ppb (2 µg/m3). This ability has been fully demonstrated by the deployment of the instrument to the Superfund site at Moffett Naval Air Station in Mountain View, California where contaminated ground water results in vapor intrusion of TCE and PCE. For two weeks, the instrument operated continuously and autonomously, successfully measuring TCE and PCE concentrations in both the breathing zone and steam tunnel air, in excellent agreement with previous TO-15 data. In this poster, we present laboratory performance data targeting new toxic molecules with the same instrument. We have demonstrated the measurement of trichlorofluolomethane (Freon 11) in zero air with a precision of 1 ppb (3σ at 1075cm-1), and hexafluoropropene in zero air with a precision of about 0.3 ppb (3σ per spectrum). The iCRDS instrument has shown the ability to continuously and autonomously measure sub-ppb levels of toxic VOCs in the lab/field, offering an unprecedented picture of the short term dynamics associated with vapor intrusion and ground water pollution.

Impact of cigarette smoking on volatile organic compound (VOC) blood levels in the U.S. population: NHANES 2003-2004.

Science.gov (United States)

Chambers, David M; Ocariz, Jessica M; McGuirk, Maureen F; Blount, Benjamin C

2011-11-01

The impact of cigarette smoking on volatile organic compound (VOC) blood levels is studied using 2003-2004 National Health and Nutrition Examination Survey (NHANES) data. Cigarette smoke exposure is shown to be a predominant source of benzene, toluene, ethylbenzene, xylenes and styrene (BTEXS) measured in blood as determined by (1) differences in central tendency and interquartile VOC blood levels between daily smokers [≥1 cigarette per day (CPD)] and less-than-daily smokers, (2) correlation among BTEXS and the 2,5-dimethylfuran (2,5-DMF) smoking biomarker in the blood of daily smokers, and (3) regression modeling of BTEXS blood levels versus categorized CPD. Smoking status was determined by 2,5-DMF blood level using a cutpoint of 0.014 ng/ml estimated by regression modeling of the weighted data and confirmed with receiver operator curve (ROC) analysis. The BTEXS blood levels among daily smokers were moderately-to-strongly correlated with 2,5-DMF blood levels (correlation coefficient, r, ranging from 0.46 to 0.92). Linear regression of the geometric mean BTEXS blood levels versus categorized CPD showed clear dose-response relationship (correlation of determination, R(2), ranging from 0.81 to 0.98). Furthermore, the pattern of VOCs in blood of smokers is similar to that reported in mainstream cigarette smoke. These results show that cigarette smoking is a primary source of benzene, toluene and styrene and an important source of ethylbenzene and xylene exposure for the U.S. population, as well as the necessity of determining smoking status and factors affecting dose (e.g., CPD, time since last cigarette) in assessments involving BTEXS exposure. Published by Elsevier Ltd.

Long-term study of VOCs measured with PTR-MS at a rural site in New Hampshire with urban influences

Directory of Open Access Journals (Sweden)

R. Talbot

2009-07-01

Full Text Available A long-term, high time-resolution volatile organic compound (VOC data set from a ground site that experiences urban, rural, and marine influences in the Northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS, a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene, oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK plus methacrolein (MACR, methanol, acetone, methyl ethyl ketone (MEK, acetaldehyde, and acetic acid, and aromatic compounds (benzene, toluene, C₈ and C₉ aromatics. Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK with better known compounds (e.g., isoprene, monoterpenes, and MVK + MACR that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ~0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

Verification of T2VOC using an analytical solution for VOC transport in vadose zone

Energy Technology Data Exchange (ETDEWEB)

Shan, C. [Lawrence Berkeley Laboratory, Berkeley, CA (United States)

1995-03-01

T2VOC represents an adaption of the STMVOC to the TOUGH2 environment. In may contaminated sites, transport of volatile organic chemicals (VOC) is a serious problem which can be simulated by T2VOC. To demonstrate the accuracy and robustness of the code, we chose a practical problem of VOC transport as the test case, conducted T2VOC simulations, and compared the results of T2VOC with those of an analytical solution. The agreements between T2VOC and the analytical solutions are excellent. In addition, the numerical results of T2VOC are less sensitive to grid size and time step to a certain extent.

VOC emissions and carbon balance of two bioenergy plantations in response to nitrogen fertilization: A comparison of Miscanthus and Salix.

Science.gov (United States)

Hu, Bin; Jarosch, Ann-Mareike; Gauder, Martin; Graeff-Hönninger, Simone; Schnitzler, Jörg-Peter; Grote, Rüdiger; Rennenberg, Heinz; Kreuzwieser, Jürgen

2018-06-01

Energy crops are an important renewable source for energy production in future. To ensure high yields of crops, N fertilization is a common practice. However, knowledge on environmental impacts of bioenergy plantations, particularly in systems involving trees, and the effects of N fertilization is scarce. We studied the emission of volatile organic compounds (VOC), which negatively affect the environment by contributing to tropospheric ozone and aerosols formation, from Miscanthus and willow plantations. Particularly, we aimed at quantifying the effect of N fertilization on VOC emission. For this purpose, we determined plant traits, photosynthetic gas exchange and VOC emission rates of the two systems as affected by N fertilization (0 and 80 kg ha -1 yr -1 ). Additionally, we used a modelling approach to simulate (i) the annual VOC emission rates as well as (ii) the OH . reactivity resulting from individual VOC emitted. Total VOC emissions from Salix was 1.5- and 2.5-fold higher compared to Miscanthus in non-fertilized and fertilized plantations, respectively. Isoprene was the dominating VOC in Salix (80-130 μg g -1 DW h -1 ), whereas it was negligible in Miscanthus. We identified twenty-eight VOC compounds, which were released by Miscanthus with the green leaf volatile hexanal as well as dimethyl benzene, dihydrofuranone, phenol, and decanal as the dominant volatiles. The pattern of VOC released from this species clearly differed to the pattern emitted by Salix. OH . reactivity from VOC released by Salix was ca. 8-times higher than that of Miscanthus. N fertilization enhanced stand level VOC emissions, mainly by promoting the leaf area index and only marginally by enhancing the basal emission capacity of leaves. Considering the higher productivity of fertilized Miscanthus compared to Salix together with the considerably lower OH . reactivity per weight unit of biomass produced, qualified the C 4 -perennial grass Miscanthus as a superior source of future

Mechanistic considerations in benzene physiological model development.

Science.gov (United States)

Medinsky, M A; Kenyon, E M; Seaton, M J; Schlosser, P M

1996-12-01

Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Because benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol, and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus the potential exists for competition among various enzymes for phenol. Zonal localization of phase I and phase II enzymes in various regions of the liver acinus also impacts this competition. Biologically based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans.

VOCs in Arid soils: Technology summary

International Nuclear Information System (INIS)

1994-02-01

The Volatile Organic Compounds In Arid Soils Integrated Demonstration (VOC-Arid ID) focuses on technologies to clean up volatile organic compounds and associated contaminants in soil and groundwater at arid sites. The initial host site is the 200 West Area at DOE's Hanford site in southeastern Washington state. The primary VOC contaminant is carbon tetrachloride, in association with heavy metals and radionuclides. An estimated 580--920 metric tons of carbon tetrachloride were disposed of between 1955 and 1973, resulting in extensive soil and groundwater contamination. The VOC-Arid ID schedule has been divided into three phases of implementation. The phased approach provides for: rapid transfer of technologies to the Environmental Restoration (EM-40) programs once demonstrated; logical progression in the complexity of demonstrations based on improved understanding of the VOC problem; and leveraging of the host site EM-40 activities to reduce the overall cost of the demonstrations. During FY92 and FY93, the primary technology demonstrations within the ID were leveraged with an ongoing expedited response action at the Hanford 200 West Area, which is directed at vapor extraction of VOCs from the vadose (unsaturated) zone. Demonstration efforts are underway in the areas of subsurface characterization including: drilling and access improvements, off-gas and borehole monitoring of vadose zone VOC concentrations to aid in soil vapor extraction performance evaluation, and treatment of VOC-contaminated off-gas. These current demonstration efforts constitute Phase 1 of the ID and, because of the ongoing vadose zone ERA, can result in immediate transfer of successful technologies to EM-40

Modeling unsteady-state VOC transport in simulated waste drums

International Nuclear Information System (INIS)

Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

1994-01-01

This report is a revision of an EG ampersand G Idaho informal report originally titled Modeling VOC Transport in Simulated Waste Drums. A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the permeability had been measured

Speciated OVOC and VOC emission inventories and their implications for reactivity-based ozone control strategy in the Pearl River Delta region, China.

Science.gov (United States)

Ou, Jiamin; Zheng, Junyu; Li, Rongrong; Huang, Xiaobo; Zhong, Zhuangmin; Zhong, Liuju; Lin, Hui

2015-10-15

The increasing ground-ozone (O3) levels, accompanied by decreasing SO2, NO2, PM10 and PM2.5 concentrations benefited from air pollution control measures implemented in recent years, initiated a serious challenge to control Volatile Organic Compound (VOC) emissions in the Pearl River Delta (PRD) region, China. Speciated VOC emission inventory is fundamental for estimating Ozone Formation Potentials (OFPs) to identify key reactive VOC species and sources in order to formulate efficient O3 control strategies. With the use of the latest bulk VOC emission inventory and local source profiles, this study developed the PRD regional speciated Oxygenated Volatile Organic Compound (OVOC) and VOC emission inventories to identify the key emission-based and OFP-based VOC sources and species. Results showed that: (1) Methyl alcohol, acetone and ethyl acetate were the major constituents in the OVOC emissions from industrial solvents, household solvents, architectural paints and biogenic sources; (2) from the emission-based perspective, aromatics, alkanes, OVOCs and alkenes made up 39.2%, 28.2%, 15.9% and 10.9% of anthropogenic VOCs; (3) from the OFP-based perspective, aromatics and alkenes become predominant with contributions of 59.4% and 25.8% respectively; (4) ethene, m/p-xylene, toluene, 1,2,4-trimethyl benzene and other 24 high OFP-contributing species were the key reactive species that contributed to 52% of anthropogenic emissions and up to 80% of OFPs; and (5) industrial solvents, industrial process, gasoline vehicles and motorcycles were major emission sources of these key reactive species. Policy implications for O3 control strategy were discussed. The OFP cap was proposed to regulate VOC control policies in the PRD region due to its flexibility in reducing the overall OFP of VOC emission sources in practice. Copyright © 2015 Elsevier B.V. All rights reserved.

Volatile Organic Compounds (VOCs) measurements onboard the HALO research aircraft during OMO-ASIA

Science.gov (United States)

Safadi, Layal; Neumaier, Marco; Fischbeck, Garlich; Geiger, Felix; Förster, Eric; Tomsche, Laura; Zahn, Andreas

2017-04-01

The objective of the OMO-Asia campaign that took place in summer 2015 was to study the free-radical chemistry at higher altitudes during the Asian summer monsoon taken over a wide area of Asia. VOC measurements (e.g. acetone, acetonitrile, benzene, and toluene) were conducted using a strongly modified instrument based on a commercial Proton-Transfer-Reaction Mass Spectrometer (PTRMS) from Ionicon. The PTRMS data are generally in good agreement with VOC measurements taken by the GC instrument from Max Planck Institute for Chemistry. In the outflow of the Monsoon plume acetone and acetonitrile volume mixing ratios (VMR) up to 1500 pptV and 180 pptV have been measured, respectively, pointing to a small contribution from biomass burning sources of which acetonitrile is an important tracer. Comparison with VOCs simulated in the atmospheric chemistry model EMAC model exhibits an underestimation (factor of 3 for acetone). The measured data were analyzed with the help of 10 days back trajectories to distinguish air mass origins. For air masses originating from North America (NA) an enhancement of 500 pptV acetone relative to the atmospheric background ( 500 pptV) can be traced back to active biogenic acetone sources in the NA boreal summer. An average enhancement of 400 pptV acetone comes from the Asian summer monsoon. Acetone - CO correlations in the monsoon relative to background air is being analyzed for further characterization and estimation of the sources.

Prediction of Adsorption Equilibrium of VOCs onto Hyper-Cross-Linked Polymeric Resin at Environmentally Relevant Temperatures and Concentrations Using Inverse Gas Chromatography.

Science.gov (United States)

Jia, Lijuan; Ma, Jiakai; Shi, Qiuyi; Long, Chao

2017-01-03

Hyper-cross-linked polymeric resin (HPR) represents a class of predominantly microporous adsorbents and has good adsorption performance toward VOCs. However, adsorption equilibrium of VOCs onto HPR are limited. In this research, a novel method for predicting adsorption capacities of VOCs on HPR at environmentally relevant temperatures and concentrations using inverse gas chromatography data was proposed. Adsorption equilibrium of six VOCs (n-pentane, n-hexane, dichloromethane, acetone, benzene, 1, 2-dichloroethane) onto HPR in the temperature range of 403-443 K were measured by inverse gas chromatography (IGC). Adsorption capacities at environmentally relevant temperatures (293-328 K) and concentrations (P/P s = 0.1-0.7) were predicted using Dubinin-Radushkevich (DR) equation based on Polany's theory. Taking consideration of the swelling properties of HPR, the volume swelling ratio (r) was introduced and r·V micro was used instead of V micro determined by N 2 adsorption data at 77 K as the parameter q 0 (limiting micropore volume) of the DR equation. The results showed that the adsorption capacities of VOCs at environmentally relevant temperatures and concentrations can be predicted effectively using IGC data, the root-mean-square errors between the predicted and experimental data was below 9.63%. The results are meaningful because they allow accurate prediction of adsorption capacities of adsorbents more quickly and conveniently using IGC data.

Industrial sector-based volatile organic compound (VOC) source profiles measured in manufacturing facilities in the Pearl River Delta, China.

Science.gov (United States)

Zheng, Junyu; Yu, Yufan; Mo, Ziwei; Zhang, Zhou; Wang, Xinming; Yin, Shasha; Peng, Kang; Yang, Yang; Feng, Xiaoqiong; Cai, Huihua

2013-07-01

Industrial sector-based VOC source profiles are reported for the Pearl River Delta (PRD) region, China, based source samples (stack emissions and fugitive emissions) analyzed from sources operating under normal conditions. The industrial sectors considered are printing (letterpress, offset and gravure printing processes), wood furniture coating, shoemaking, paint manufacturing and metal surface coating. More than 250 VOC species were detected following US EPA methods TO-14 and TO-15. The results indicated that benzene and toluene were the major species associated with letterpress printing, while ethyl acetate and isopropyl alcohol were the most abundant compounds of other two printing processes. Acetone and 2-butanone were the major species observed in the shoemaking sector. The source profile patterns were found to be similar for the paint manufacturing, wood furniture coating, and metal surface coating sectors, with aromatics being the most abundant group and oxygenated VOCs (OVOCs) as the second largest contributor in the profiles. While OVOCs were one of the most significant VOC groups detected in these five industrial sectors in the PRD region, they have not been reported in most other source profile studies. Such comparisons with other studies show that there are differences in source profiles for different regions or countries, indicating the importance of developing local source profiles. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

PTR-MS in environmental research: biogenic VOCs

International Nuclear Information System (INIS)

Beauchamp, J.; Grabmer, W.; Graus, M.; Wisthaler, A.; Hansel, A.

2004-01-01

Proton-transfer-reaction mass spectrometry (PTR-MS) is a chemical ionization mass spectrometry technique that allows for on-line measurements of volatile organic compounds (VOCs) at pptV levels. This well established analytical tool has been used in a broad variety of research, including the investigation of VOCs in various foods (e.g. for quality control or food degradation studies), as well as being used as a tool for non-invasive medical diagnostics (e.g. human breath analysis). In addition to these fields of study, PTR-MS has been widely used in environmental research, from trace gas analysis in the troposphere to VOC emissions from plants. Participation in two field campaigns (BEWA and ECHO - both part of the German AFO 2000 program) by the Institute of Ion Physics involved a variety of investigations for monitoring biogenic emissions. These included the technique of disjunct eddy covariance for flux measurements above a forest canopy, C-13 carbon labelling experiments to follow carbon use in a plant, and stress-induced VOC emission investigations to gain understanding of how plants react to stress (e.g. ozone exposure). A selection of results from these investigations will be discussed in this presentation. (author)

Impacts of a large boreal wildfire on ground level atmospheric concentrations of PAHs, VOCs and ozone

Science.gov (United States)

Wentworth, Gregory R.; Aklilu, Yayne-abeba; Landis, Matthew S.; Hsu, Yu-Mei

2018-04-01

During May 2016 a very large boreal wildfire burned throughout the Athabasca Oil Sands Region (AOSR) in central Canada, and in close proximity to an extensive air quality monitoring network. This study examines speciated 24-h integrated polycyclic aromatic hydrocarbon (PAH) and volatile organic compound (VOC) measurements collected every sixth day at four and seven sites, respectively, from May to August 2016. The sum of PAHs (ΣPAH) was on average 17 times higher in fire-influenced samples (852 ng m-3, n = 8), relative to non-fire influenced samples (50 ng m-3, n = 64). Diagnostic PAH ratios in fire-influenced samples were indicative of a biomass burning source, whereas ratios in June to August samples showed additional influence from petrogenic and fossil fuel combustion. The average increase in the sum of VOCs (ΣVOC) was minor by comparison: 63 ppbv for fire-influenced samples (n = 16) versus 46 ppbv for non-fire samples (n = 90). The samples collected on August 16th and 22nd had large ΣVOC concentrations at all sites (average of 123 ppbv) that were unrelated to wildfire emissions, and composed primarily of acetaldehyde and methanol suggesting a photochemically aged air mass. Normalized excess enhancement ratios (ERs) were calculated for 20 VOCs and 23 PAHs for three fire influenced samples, and the former were generally consistent with previous observations. To our knowledge, this is the first study to report ER measurements for a number of VOCs and PAHs in fresh North American boreal wildfire plumes. During May the aged wildfire plume intercepted the cities of Edmonton (∼380 km south) or Lethbridge (∼790 km south) on four separate occasions. No enhancement in ground-level ozone (O3) was observed in these aged plumes despite an assumed increase in O3 precursors. In the AOSR, the only daily-averaged VOCs which approached or exceeded the hourly Alberta Ambient Air Quality Objectives (AAAQOs) were benzene (during the fire) and acetaldehyde (on August 16th

Mechanistic considerations in benzene physiological model development.

OpenAIRE

Medinsky, M A; Kenyon, E M; Seaton, M J; Schlosser, P M

1996-01-01

Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergis...

Evaluating the effectiveness of joint emission control policies on the reduction of ambient VOCs: Implications from observation during the 2014 APEC summit in suburban Beijing

Science.gov (United States)

Li, Kun; Li, Junling; Wang, Weigang; Tong, Shengrui; Liggio, John; Ge, Maofa

2017-09-01

Ambient volatile organic compounds (VOCs) at a suburban Beijing site were on-line detected using proton transfer reaction-mass spectrometry (PTR-MS) during autumn of 2014, near the location of the Asia-Pacific Economic Cooperation (APEC) summit. During the APEC summit, the Chinese government enacted strict emission control policies. It was found that VOC concentrations only slightly decreased during the first emission control period (EC I), when control policies were performed in Beijing and 5 cities along the Tai-hang Mountains. However, most of the VOCs (10 out of 12 non-biogenic species) significantly decreased (more than 40%) during the second emission control period (EC II), when control policies were carried out in 16 cities including Beijing, Tianjin, 8 cities of Hebei province and 6 cities of Shandong province. Also the ratio of toluene and benzene decreased during EC II, likely because the emission control policies changed the proportions of different anthropogenic sources. Using the positive matrix factorization (PMF) source apportionment method, five factors are analyzed: (1) vehicle + fuel, (2) solvent, (3) biomass burning, (4) secondary, and (5) background + long-lived. Among them, vehicle + fuel, solvent and biomass burning contribute most of the VOCs concentrations (60%-80%) during the polluted periods and are affected most by emission control policies. During EC II, the reductions of vehicle + fuel, solvent, biomass burning and secondary species were all no less than 50%. Overall, when emission control policies were carried out in many North China Plain (NCP) cities (i.e. EC II), the VOC concentrations of suburban Beijing markedly decreased. This indicates the cross-regional joint-control policies have a large influence on reductions of organic gas species. The findings of this study have vital implications for helping formulate effective emission control policies in China and other countries.

Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.

Science.gov (United States)

Gallego, E; Perales, J F; Roca, F J; Guardino, X

2014-02-01

Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones

Field observations of volatile organic compound (VOC) exchange in red oaks

Science.gov (United States)

Cappellin, Luca; Algarra Alarcon, Alberto; Herdlinger-Blatt, Irina; Sanchez, Juaquin; Biasioli, Franco; Martin, Scot T.; Loreto, Francesco; McKinney, Karena A.

2017-03-01

Volatile organic compounds (VOCs) emitted by forests strongly affect the chemical composition of the atmosphere. While the emission of isoprenoids has been largely characterized, forests also exchange many oxygenated VOCs (oVOCs), including methanol, acetone, methyl ethyl ketone (MEK), and acetaldehyde, which are less well understood. We monitored total branch-level exchange of VOCs of a strong isoprene emitter (Quercus rubra L.) in a mixed forest in New England, where canopy-level fluxes of VOCs had been previously measured. We report daily exchange of several oVOCs and investigated unknown sources and sinks, finding several novel insights. In particular, we found that emission of MEK is linked to uptake of methyl vinyl ketone (MVK), a product of isoprene oxidation. The link was confirmed by corollary experiments proving in vivo detoxification of MVK, which is harmful to plants. Comparison of MEK, MVK, and isoprene fluxes provided an indirect indication of within-plant isoprene oxidation. Furthermore, besides confirming bidirectional exchange of acetaldehyde, we also report for the first time direct evidence of benzaldehyde bidirectional exchange in forest plants. Net emission or deposition of benzaldehyde was found in different periods of measurements, indicating an unknown foliar sink that may influence atmospheric concentrations. Other VOCs, including methanol, acetone, and monoterpenes, showed clear daily emission trends but no deposition. Measured VOC emission and deposition rates were generally consistent with their ecosystem-scale flux measurements at a nearby site.

New device for time-averaged measurement of volatile organic compounds (VOCs)

Energy Technology Data Exchange (ETDEWEB)

Santiago Sánchez, Noemí; Tejada Alarcón, Sergio; Tortajada Santonja, Rafael; Llorca-Pórcel, Julio, E-mail: julio.llorca@aqualogy.net

2014-07-01

Contamination by volatile organic compounds (VOCs) in the environment is an increasing concern since these compounds are harmful to ecosystems and even to human health. Actually, many of them are considered toxic and/or carcinogenic. The main sources of pollution come from very diffuse focal points such as industrial discharges, urban water and accidental spills as these compounds may be present in many products and processes (i.e., paints, fuels, petroleum products, raw materials, solvents, etc.) making their control difficult. The presence of these compounds in groundwater, influenced by discharges, leachate or effluents of WWTPs is especially problematic. In recent years, law has been increasingly restrictive with the emissions of these compounds. From an environmental point of view, the European Water Framework Directive (2000/60/EC) sets out some VOCs as priority substances. This binding directive sets guidelines to control compounds such as benzene, chloroform, and carbon tetrachloride to be at a very low level of concentration and with a very high frequency of analysis. The presence of VOCs in the various effluents is often highly variable and discontinuous since it depends on the variability of the sources of contamination. Therefore, in order to have complete information of the presence of these contaminants and to effectively take preventive measures, it is important to continuously control, requiring the development of new devices which obtain average concentrations over time. As of today, due to technical limitations, there are no devices on the market that allow continuous sampling of these compounds in an efficient way and to facilitate sufficient detection limits to meet the legal requirements which are capable of detecting very sporadic and of short duration discharges. LABAQUA has developed a device which consists of a small peristaltic pump controlled by an electronic board that governs its operation by pre-programming. A constant flow passes

Occupational exposure to benzene in South Korea.

Science.gov (United States)

Kang, Seong-Kyu; Lee, Mi-Young; Kim, Tae-Kyun; Lee, Jeong-Oh; Ahn, Yeon Soon

2005-05-30

Benzene has been used in various industries as glues or solvents in Korea. Since 1981, a preparation containing more than 1% benzene is not allowed to be manufactured, used or dealt with in the workplace, except in laboratories and in those situations benzene must be used in a completely sealed process as specified in Industrial Safety and Health Act (ISHA). Claims for compensation of hematopoietic diseases related to benzene have been rising even though the work environment has been improved. This study was conducted to assess the status of benzene exposure in different industries in Korea. We reviewed the claimed cases investigated by the Korea Occupational Safety and Health Agency (KOSHA) between 1992 and 2000. The Survey of National Work Environment Status in 1998 was analyzed to assume the number of workers and factories exposed to benzene. In 2000, six factories were investigated to evaluate benzene exposure. Personal air monitoring was performed in 61 workers and urine samples were collected from 57 workers to measure trans,trans-muconic acid (t,t-MA). Hematologic examination has performed. Thirty-four cases of hematopoietic diseases were investigated by KOSHA including eight cases of myelodysplastic syndrome and eight cases of acute myelocytic leukemia. Eight cases were accepted as related to benzene exposure. The number of workers possibly exposed to benzene can be estimated to be 196,182 workers from 6219 factories based on the database. The geometric mean of benzene in air was 0.094 (0.005-5.311) ppm. Seven samples were higher than 1 ppm but they did not go over the 10 ppm occupational exposure limit (OEL) value in Korea. The geometric mean of trans,trans-muconic acid in urine was 0.966 (0.24-2.74) mg/g creatinine. The benzene exposure level was low except in a factory where benzene was used to polymerize other chemicals. The ambient benzene from 0.1 to 1 ppm was significantly correlated with urine t,t-MA concentration (r=0.733, p<0.01). Hematologic

Benzene: a case study in parent chemical and metabolite interactions.

Science.gov (United States)

Medinsky, M A; Kenyon, E M; Schlosser, P M

1995-12-28

Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia and pancytopenia, and acute myelogenous leukemia. A combination of metabolites (hydroquinone and phenol for example) is apparently necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Since benzene and its hydroxylated metabolites (phenol, hydroquinone and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus, the potential exists for competition among various enzymes for phenol. However, zonal localization of Phase I and Phase II enzymes in various regions of the liver acinus regulates this competition. Biologically-based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans.

Benzene: questions and answers

International Nuclear Information System (INIS)

1999-01-01

This information booklet is intended to inform residents near natural gas dehydration facilities about benzene and its levels in the atmosphere. It was issued following the federal government's decision to place benzene on its Priority Substances List and to require industry to establish means for reducing benzene emissions from natural gas dehydrators and to inform residents about benzene emissions from glycol dehydration facilities. Accordingly, the booklet explains what benzene is (a colourless flammable liquid component of hydrocarbons) how it gets into the air (during gasoline refining, vehicle refueling and the production of steel and petrochemicals), the associated health hazards (a recognized carcinogen, causing an increased incidence of leukemia in concentrations of 100 parts per million), defines a glycol dehydrator (a facility built at or near some natural gas fields for the removal of water from the natural gas to prevent corrosion and freezing of pipelines), and enumerates the steps that are being taken to reduce benzene levels in the air (benzene levels in gasoline have been reduced, along with benzene emissions from petrochemical plants, refineries, steel plants and glycol dehydrators by 54 per cent to date; this will rise to 90 per cent by 2005). In addition to these actions, industry plans call for all existing glycol dehydrators within 750 metres of any permanent residence to be limited to benzene emissions of no more than three tonnes per year before 2001; new glycol dehydrators after that date will be expected to have benzene emissions reduced to the lowest level that can be practically achieved

Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley

Directory of Open Access Journals (Sweden)

C. Sarkar

2016-03-01

Full Text Available The Kathmandu Valley in Nepal suffers from severe wintertime air pollution. Volatile organic compounds (VOCs are key constituents of air pollution, though their specific role in the valley is poorly understood due to insufficient data. During the SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley–Atmospheric Brown Clouds field campaign conducted in Nepal in the winter of 2012–2013, a comprehensive study was carried out to characterise the chemical composition of ambient Kathmandu air, including the determination of speciated VOCs, by deploying a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS – the first such deployment in South Asia. In the study, 71 ion peaks (for which measured ambient concentrations exceeded the 2σ detection limit were detected in the PTR-TOF-MS mass scan data, highlighting the chemical complexity of ambient air in the valley. Of the 71 species, 37 were found to have campaign average concentrations greater than 200 ppt and were identified based on their spectral characteristics, ambient diel profiles and correlation with specific emission tracers as a result of the high mass resolution (m ∕ Δm  >  4200 and temporal resolution (1 min of the PTR-TOF-MS. The concentration ranking in the average VOC mixing ratios during our wintertime deployment was acetaldehyde (8.8 ppb  >  methanol (7.4 ppb  >  acetone + propanal (4.2 ppb  >  benzene (2.7 ppb  >  toluene (1.5 ppb  >  isoprene (1.1 ppb  >  acetonitrile (1.1 ppb  >  C8-aromatics ( ∼ 1 ppb  >  furan ( ∼ 0.5 ppb  >  C9-aromatics (0.4 ppb. Distinct diel profiles were observed for the nominal isobaric compounds isoprene (m ∕ z  =  69.070 and furan (m ∕ z  =  69.033. Comparison with wintertime measurements from several locations elsewhere in the world showed mixing ratios of acetaldehyde ( ∼  9 ppb, acetonitrile ( ∼  1 ppb and isoprene

Tropospheric VOC measurements by PTR-MS

International Nuclear Information System (INIS)

Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

2002-01-01

Full text: O 3 is formed photochemically from the photolysis of NO 2 , and because O 3 reacts rapidly with NO these reactions result in a photoequilibrium between NO, NO 2 with no net formation or loss of O 3 , However, in the presence of volatile organic compounds (VOCs), the degradation reactions of VOCs lead to the formation of intermediate peroxy radicals which react with NO, converting NO to NO 2 , which then photolyze to form O 3 . Thus, in order to understand quantitatively tropospheric ozone chemistry, it is necessary to know the VOC distribution within the troposphere as well as VOC fluxes from individual sources. Examples will be presented how the use of Proton Transfer Reaction Mass Spectrometry (PTR-MS) has enhanced our understanding of anthropogenic VOC emissions, biosphere-atmosphere exchange processes, and photochemical processing of both anthropogenic and biogenic VOCs in the troposphere. (author)

VOC emissions control systems

International Nuclear Information System (INIS)

Spessard, J.E.

1993-01-01

The air pollution control equipment marketplace offers many competing technologies for controlling emissions of volatile organic compounds (VOC) in air. If any technology was economically and technically superior under all conditions, it would be the only one on the market. In fact, each technology used to control VOCs is superior under some set of conditions. The reasons for choosing one control technology over another are situation-specific. Some general guidelines to VOC control technologies and the situations where each may be appropriate are presented in this article. The control technologies and applications are summarized in a table

Risk factor benzene

Energy Technology Data Exchange (ETDEWEB)

Stobbe, H.

1981-01-01

Nearly one hundred years ago clinical and epidemiological studies have already assigned benzene as a markedly haematotoxic substance. Nowadays benzene is known as an important professional noxa, which is straight off directed against the haematopoietic system, essentially to a dose-time-effect. By this it can be taken as a model also for other noxious substances. Similar solvents often contain so-called 'hidden benzene', that means not declared benzene, so that the consumer doesn't know what dangerous substance are available for his personal use. Impairments caused by benzene mostly are manifested earliest after months, years or for tens of years, and the point is, that these haematopoietic disorders are irreversible disturbances of the haematopoietic stem cell compartment. The consequence of this fact is a deep involvement of the proliferation of the erythro-, mono-, granulo- and thrombopoietic cell lines, mostly with predominance of one of these myeloproliferative cell systems. In the further progression of the impairments due to benzene three different clinical pictures can be observed: the aplastic bone marrow syndrome (i.e. aplastic anemia), the haematopoietic dysplasia (i.e. preleukemia) and the acute leukemias (with the subtypes erythroleukosis, myeloblastic-promyelocytic or myelomonocytic from respectively). Also the transition from one clinical picture to another is possible.

Utilisation of VOC in Diesel Engines. Ignition and combustion of VOC released in crude oil tankers

International Nuclear Information System (INIS)

Melhus, Oeyvin

2002-01-01

The emission of VOC (Volatile Organic Compound) is a significant source of hydrocarbon pollution. In Norway, the offshore oil industry represents a major source. This emission represents both an energy loss and an environmental problem. Gas tankers have used boil-off gas from the cargo tanks as fuel for some time. However, for the current VOC project a new fuel injection concept is designed for tankers to take advantage of the energy present in the VOC evaporated from crude oil. The VOC is mixed with inert gas in these tankers, and thus the utilisation of this gas represents new challenges. The VOC project uses the concept of ''Condensate Diesel Process'' with pilot ignition. An experimental study of ignition and combustion of VOC Fuels reported here was initiated by the time it was decided to start a pilot project converting propulsion engines in shuttle tankers to use VOC Fuel. It is an experimental study carried out at the Marine Technology Centre (MTS). The objective was to study ignition and combustion of the chosen process in comparison with an ordinary diesel process. The experimental results have been discussed and compared with theoretical considerations of injection, ignition and combustion. For experiments on combustion, a rapid compression machine ''DyFo'' was redesigned to use VOC Fuel. The DyFo test rig was initially designed to study ignition and early combustion of spark ignited homogeneous gas/air charges. To study the ignition and early combustion of VOC Fuel injected at high pressure and ignited by pilot diesel fuel, a redesign was necessary. An important feature of the DyFo, is the visualisation of the combustion. The advantage of the DyFo test rig over an engine, is its simplicity and controllability. In an engine the visualisation would suffer from combustion deposits disturbing the view through the quartz glasses, making the images more difficult to interpret. The simplicity is on the other side a drawback. Correct thermal conditions inside

New device for time-averaged measurement of volatile organic compounds (VOCs).

Science.gov (United States)

Santiago Sánchez, Noemí; Tejada Alarcón, Sergio; Tortajada Santonja, Rafael; Llorca-Pórcel, Julio

2014-07-01

Contamination by volatile organic compounds (VOCs) in the environment is an increasing concern since these compounds are harmful to ecosystems and even to human health. Actually, many of them are considered toxic and/or carcinogenic. The main sources of pollution come from very diffuse focal points such as industrial discharges, urban water and accidental spills as these compounds may be present in many products and processes (i.e., paints, fuels, petroleum products, raw materials, solvents, etc.) making their control difficult. The presence of these compounds in groundwater, influenced by discharges, leachate or effluents of WWTPs is especially problematic. In recent years, law has been increasingly restrictive with the emissions of these compounds. From an environmental point of view, the European Water Framework Directive (2000/60/EC) sets out some VOCs as priority substances. This binding directive sets guidelines to control compounds such as benzene, chloroform, and carbon tetrachloride to be at a very low level of concentration and with a very high frequency of analysis. The presence of VOCs in the various effluents is often highly variable and discontinuous since it depends on the variability of the sources of contamination. Therefore, in order to have complete information of the presence of these contaminants and to effectively take preventive measures, it is important to continuously control, requiring the development of new devices which obtain average concentrations over time. As of today, due to technical limitations, there are no devices on the market that allow continuous sampling of these compounds in an efficient way and to facilitate sufficient detection limits to meet the legal requirements which are capable of detecting very sporadic and of short duration discharges. LABAQUA has developed a device which consists of a small peristaltic pump controlled by an electronic board that governs its operation by pre-programming. A constant flow passes

Distribution of VOCs between air and snow at the Jungfraujoch high alpine research station, Switzerland, during CLACE 5 (winter 2006

Directory of Open Access Journals (Sweden)

E. Starokozhev

2009-05-01

Full Text Available Volatile organic compounds (VOCs were analyzed in air and snow samples at the Jungfraujoch high alpine research station in Switzerland as part of CLACE 5 (CLoud and Aerosol Characterization Experiment during February/March 2006. The fluxes of individual compounds in ambient air were calculated from gas phase concentrations and wind speed. The highest concentrations and flux values were observed for the aromatic hydrocarbons benzene (14.3 μg.m⁻² s⁻¹, 1,3,5-trimethylbenzene (5.27 μg.m⁻² s⁻¹, toluene (4.40 μg.m^{−2 −1}, and the aliphatic hydrocarbons i-butane (7.87 μg.m⁻² s⁻¹, i-pentane (3.61 μg.m⁻² s⁻¹ and n-butane (3.23 μg.m⁻² s⁻¹. The measured concentrations and fluxes were used to calculate the efficiency of removal of VOCs by snow, which is defined as difference between the initial and final concentration/flux values of compounds before and after wet deposition. The removal efficiency was calculated at −24°C (−13.7°C and ranged from 37% (35% for o-xylene to 93% (63% for i-pentane. The distribution coefficients of VOCs between the air and snow phases were derived from published poly-parameter linear free energy relationship (pp-LFER data, and compared with distribution coefficients obtained from the simultaneous measurements of VOC concentrations in air and snow at Jungfraujoch. The coefficients calculated from pp-LFER exceeded those values measured in the present study, which indicates more efficient snow scavenging of the VOCs investigated than suggested by theoretical predictions.

Development of a novel biofilter for aerobic biodegradation of volatile organic compounds (VOCs)

International Nuclear Information System (INIS)

Govind, R.; Utgikar, V.; Shan, Y.; Zhao, Wang; Sayles, G.D.; Bishop, D.F.; Safferman, S.I.

1992-01-01

In recent years, the emission into the atmosphere of volatile organic compounds (VOCs) has undergone increased regulation by EPA, OSHA and other government agencies due to potential human health hazards. The sources of these VOCs include releases during industrial production and use, from contaminated wastewaters in collection systems and treatment plants, and from hazardous wastes in landfills and contaminated ground water. Conventional methods for treating VOC emissions include adsorption on solids, absorption in solvents, incineration and catalytic oxidation. One alternative to these conventional treatment methods is the biological destruction of the VOCs in gas phase biofilters. This method has the advantage of pollution destruction (as compared to transfer to another medium) at lower operation and maintenance costs. The biofilter method also can be combined with various stripping or vapor extraction separation processes which effectively transfer VOCs from liquid or solid matrices into the gas phase entering biofilters

Analysis of Sidestream Smoke VOCs and Characterization of their Odor Profiles by VOC Preconcentrator-GC-O Techniques

Directory of Open Access Journals (Sweden)

Higashi N

2014-12-01

Full Text Available Various techniques have been employed in the analysis of volatile organic compounds (VOCs. However, these techniques are insufficient for the precise analysis of tobacco smoke VOCs because of the complexity of the operating system, system instability, or poor sensitivity. To overcome these problems, a combined system of VOC preconcentrator, gas chromatograph, and olfactometer has been developed. The performance of this new system was evaluated in the analysis of VOCs in tobacco smoke and applied to the odor profiling of sidestream smoke (SSS that has not been sufficiently investigated in the past.

Measurements of VOC adsorption/desorption characteristics of typical interior building materials

Energy Technology Data Exchange (ETDEWEB)

An, Y.; Zhang, J.S.; Shaw, C.Y.

2000-07-01

The adsorption/desorption of volatile organic compounds (VOCs) on interior building material surfaces (i.e., the sink effect) can affect the VOC concentrations in a building, and thus need to be accounted for an indoor air quality (IAQ) prediction model. In this study, the VOC adsorption/desorption characteristics (sink effect) were measured for four typical interior building materials including carpet, vinyl floor tile, painted drywall, and ceiling tile. The VOCs tested were ethylbenzene, cyclohexanone, 1,4-dichlorobenzene, benzaldehyde, and dodecane. These five VOCs were selected because they are representative of hydrocarbons, aromatics, ketones, aldehydes, and chlorine substituted compounds. The first order reversible adsorption/desorption model was based on the Langmuir isotherm was used to analyze the data and to determine the equilibrium constant of each VOC-material combination. It was found that the adsorption/desorption equilibrium constant, which is a measure of the sink capacity, increased linearly with the inverse of the VOC vapor pressure. For each compound, the adsorption/desorption equilibrium constant, and the adsorption rate constant differed significantly among the four materials tested. A detailed characterization of the material structure in the micro-scale would improve the understanding and modeling of the sink effect in the future. The results of this study can be used to estimate the impact of sink effect on the VOC concentrations in buildings.

Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene

Directory of Open Access Journals (Sweden)

Zhengjun Zhang

2011-12-01

Full Text Available Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering.

Aromaticity of benzene in condensed phases. A case of a benzene-water system

Science.gov (United States)

Zborowski, Krzysztof K.

2014-05-01

A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

Variability of benzene exposure among filling station attendants

International Nuclear Information System (INIS)

Carere, A.; Iacovella, N.; Turrio Baldassarri, L.; Fuselli, S.; Iavarone, I.; Lagorio, S.; Proietto, A.R.

1996-12-01

A monitoring survey of filling station attendants aimed at identifying sources of variability of exposure to benzene and other aromatics was carried out. Concurrent samples of the worker's breathing zone air, atmospheric air in the service station proximity, and gasoline were collected, along with information about daily workloads and other exposure-related factors. Benzene personal exposure was characterised by a small between-worker variability and a predominant within-worker variance component. Such elevated day-to-day variability yields to imprecise estimates of mean personal exposure. Almost 70% of the overall personal exposure variance was explained by a model including daily benzene from dispensed fuel, presence of a shelter over the refueling area, amount of fuel supplied to the station if a delivery occurred, and background atmospheric benzene concentration

Superfund record of decision (EPA Region 4): Potter's septic tank service pits site, Brunswick County, Sandy Creek, NC. (First remedial action), August 1992. Final report

International Nuclear Information System (INIS)

1992-01-01

The 5-acre Potter's Septic Tank Service Pits (Potter's Pits) is located in a rural section of Brunswick County, North Carolina. The site is situated within a residential community known as the Town of Sandy Creek. Disposal practices consisted of placing petroleum waste products and septic tank sludges either in shallow unlined pits or directly on the land surface. The ROD addresses the ground water treatment and contaminated soils at the site. Primary contaminants of concern affecting surface and subsurface soil are VOCs and semi-VOCs, including napthalene, metals, and pesticides. Ground water is contaminated with VOCs, including benzene, ethyl benzene, toluene; other organics including naphthalene, and xylenes; and metals, including chromium and lead. The selected remedial action for the site includes excavating all soils that exceed the soil clean-up standards; treating contaminated soils by using an onsite ex-situ thermal desorption process; performing secondary treatment of the concentrated organic contaminants, and sampling and analyzing the treatment residue

Measurements of Volatile Organic Compounds Using Proton Transfer Reaction – Mass Spectrometry during the MILAGRO 2006 Campaign

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E. C. Fortner

2009-01-01

Full Text Available Volatile organic compounds (VOCs were measured by proton transfer reaction – mass spectrometry (PTR-MS on a rooftop in the urban mixed residential and industrial area North Northeast of downtown Mexico City as part of the Megacity Initiative – Local and Global Research Observations (MILAGRO 2006 field campaign. Thirty eight individual masses were monitored during the campaign and many species were quantified including methanol, acetaldehyde, toluene, the sum of C₂ benzenes, the sum of C₃ benzenes, acetone, isoprene, benzene, and ethyl acetate. The VOC measurements were analyzed to gain a better understanding of the type of VOCs present in the MCMA, their diurnal patterns, and their origins. Diurnal profiles of weekday and weekend/holiday aromatic VOC concentrations showed the influence of vehicular traffic during the morning rush hours and during the afternoon hours. Plumes including elevated toluene as high as 216 parts per billion (ppb and ethyl acetate as high as 183 ppb were frequently observed during the late night and early morning hours, indicating the possibility of significant industrial sources of the two compounds in the region. Wind fields during those peak episodes revealed no specific direction for the majority of the toluene plumes but the ethyl acetate plumes arrived at the site when winds were from the Southwest or West. The PTR-MS measurements combined with other VOC measuring techniques at the field site as well as VOC measurements conducted in other areas of the Mexico City Metropolitan Area (MCMA will help to develop a better understanding of the spatial pattern of VOCs and its variability in the MCMA.

A DFT study of volatile organic compounds adsorption on transition metal deposited graphene

International Nuclear Information System (INIS)

Kunaseth, Manaschai; Poldorn, Preeyaporn; Junkeaw, Anchalee; Meeprasert, Jittima; Rungnim, Chompoonut; Namuangruk, Supawadee; Kungwan, Nawee; Inntam, Chan; Jungsuttiwong, Siriporn

2017-01-01

Highlights: • VOCs removal via modified carbon-based adsorbent using density functional theory. • The single-vacancy defective graphene (SDG) with metal-deposited significantly increase the adsorption efficiency. • TM-doped SDG is a suitable adsorbent material for VOC removal. • Electron in hybridized sp"2-orbitals of heteroatoms has an effect on mode of adsorption. - Abstract: Recently, elevated global emission of volatile organic compounds (VOCs) was associated to the acceleration and increasing severity of climate change worldwide. In this work, we investigated the performance of VOCs removal via modified carbon-based adsorbent using density functional theory. Here, four transition metals (TMs) including Pd, Pt, Ag, and Au were deposited onto single-vacancy defective graphene (SDG) surface to increase the adsorption efficiency. Five prototypical VOCs including benzene, furan, pyrrole, pyridine, and thiophene were used to study the adsorption capability of metal-deposited graphene adsorbent. Calculation results revealed that Pd, Pt, Au, and Ag atoms and nanoclusters bind strongly onto the SDG surface. In this study, benzene, furan and pyrrole bind in the π-interaction mode using delocalized π-electron in aromatic ring, while pyridine and thiophene favor X- interaction mode, donating lone pair electron from heteroatom. In terms of adsorption, pyridine VOC adsorption strengths to the TM-cluster doped SDG surfaces are Pt_4 (−2.11 eV) > Pd_4 (−2.05 eV) > Ag_4 (−1.53 eV) > Au_4 (−1.87 eV). Our findings indicate that TM-doped SDG is a suitable adsorbent material for VOC removal. In addition, partial density of states analysis suggests that benzene, furan, and pyrrole interactions with TM cluster are based on p-orbitals of carbon atoms, while pyridine and thiophene interactions are facilitated by hybridized sp"2-orbitals of heteroatoms. This work provides a key insight into the fundamentals of VOCs adsorption on carbon-based adsorbent.

Advances in Biodegradation of Multiple Volatile Organic Compounds

Science.gov (United States)

Zhang, M.; Yoshikawa, M.

2017-12-01

Bioremediation of soil and groundwater containing multiple contaminants remains a challenge in environmental science and engineering because complete biodegradation of all components is necessary but very difficult to accomplish in practice. This presentation provides a brief overview on advances in biodegradation of multiple volatile organic compounds (VOCs) including chlorinated ethylenes, benzene, toluene and dichloromethane (DCM). Case studies on aerobic biodegradation of benzene, toluene and DCM, and integrated anaerobic-aerobic biodegradation of 7 contaminants, specifically, tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), vinyl chloride (VC), DCM, benzene and toluene will be provided. Recent findings based on systematic laboratory experiments indicated that aerobic toluene degradation can be enhanced by co-existence of benzene. Propioniferax, not a known benzene, toluene and DCM degrader can be a key microorganism that involves in biodegradation when the three contaminants co-exist. Integrated anaerobic-aerobic biodegradation is capable of completely degrading the seven VOCs with initial concentrations less than 30 mg/L. Dehalococcoides sp., generally considered sensitive to oxygen, can survive aerobic conditions for at least 28 days, and can be activated during the subsequent anaerobic biodegradation. This presentation may provide a systematic information about biodegradation of multiple VOCs, and a scientific basis for the complete bioremediation of multiple contaminants in situ.

Benzene Monitor System report

International Nuclear Information System (INIS)

Livingston, R.R.

1992-01-01

Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale open-quotes SRAT/SME/PRclose quotes and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard trademark sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system (±0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge ampersand trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer's computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants)

Biogenic VOC Emissions from Tropical Landscapes

Science.gov (United States)

Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

2003-04-01

Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

Benzene exposure and risk of non-Hodgkin lymphoma.

Science.gov (United States)

Smith, Martyn T; Jones, Rachael M; Smith, Allan H

2007-03-01

Exposure to benzene, an important industrial chemical and component of gasoline, is a widely recognized cause of leukemia, but its association with non-Hodgkin lymphoma (NHL) is less clear. To clarify this issue, we undertook a systematic review of all case-control and cohort studies that identified probable occupational exposures to benzene and NHL morbidity or mortality. We identified 43 case-control studies of NHL outcomes that recognized persons with probable occupational exposure to benzene. Forty of these 43 (93%) studies show some elevation of NHL risk, with 23 of 43 (53%) studies finding statistically significant associations between NHL risk and probable benzene exposure. We also identified 26 studies of petroleum refinery workers reporting morbidity or mortality for lymphomas and all neoplasms and found that in 23 (88%), the rate of lymphoma morbidity or mortality was higher than that for all neoplasms. A substantial healthy-worker effect was evident in many of the studies and a comprehensive reevaluation of these studies with appropriate adjustments should be undertaken. Numerous studies have also reported associations between benzene exposure and the induction of lymphomas in mice. Further, because benzene is similar to alkylating drugs and radiation in producing leukemia, it is plausible that it might also produce lymphoma as they do and by similar mechanisms. Potential mechanisms include immunotoxicity and the induction of double-strand breaks with subsequent chromosome damage resulting in translocations and deletions. We conclude that, overall, the evidence supports an association between occupational benzene exposure and NHL.

Dehydrogenation of benzene on Pt(111) surface

Science.gov (United States)

Gao, W.; Zheng, W. T.; Jiang, Q.

2008-10-01

The dehydrogenation of benzene on Pt(111) surface is studied by ab initio density functional theory. The minimum energy pathways for benzene dehydrogenation are found with the nudge elastic band method including several factors of the associated barriers, reactive energies, intermediates, and transient states. The results show that there are two possible parallel minimum energy pathways on the Pt(111) surface. Moreover, the tilting angle of the H atom in benzene can be taken as an index for the actual barrier of dehydrogenation. In addition, the properties of dehydrogenation radicals on the Pt(111) surface are explored through their adsorption energy, adsorption geometry, and electronic structure on the surface. The vibrational frequencies of the dehydrogenation radicals derived from the calculations are in agreement with literature data.

Anaerobic degradation of benzene by marine sulfate-reducing bacteria

Science.gov (United States)

Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

2010-05-01

Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

PROCESS SIMULATION OF BENZENE SEPARATION COLUMN OF LINEAR ALKYL BENZENE (LABPLANT

Directory of Open Access Journals (Sweden)

Zaid A. AbdelRahman

2013-05-01

Full Text Available       CHEMCAD process simulator was used for the analysis of existing benzene separation column in LAB plant(Arab Detergent Company/Beiji-Iraq.         Simulated column performance curves were constructed. The variables considered in this study are the thermodynamic model option, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates compositions, were constructed. Four different thermodynamic models options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.            For Benzene Column (32 real stages, feed stage 14, the simulated results show that bottom temperature above 200 oC the weight fractions of top components, except benzene, increases sharply, where as benzene top weight fraction decreasing sharply. Also, feed temperature above 180 oC  shows same trends. The column profiles remain fairly constant from tray 3 (immediately below condenser to tray 10 (immediately above feed and from tray 15 (immediately below feed to tray 25 (immediately above reboiler. Simulation of the benzene separation column in LAB production plant using CHEMCAD simulator, confirms the real plant operation data. The study gives evidence about a successful simulation with CHEMCAD.

[CoCuMnOx Photocatalyzed Oxidation of Multi-component VOCs and Kinetic Analysis].

Science.gov (United States)

Meng, Hai-long; Bo, Long-li; Liu, Jia-dong; Gao, Bo; Feng, Qi-qi; Tan, Na; Xie, Shuai

2016-05-15

Solar energy absorption coating CoCuMnOx was prepared by co-precipitation method and applied to photodegrade multi- component VOCs including toluene, ethyl acetate and acetone under visible light irradiation. The photocatalytic oxidation performance of toluene, ethyl acetate and acetone was analyzed and reaction kinetics of VOCs were investigated synchronously. The research indicated that removal rates of single-component toluene, ethyl acetate and acetone were 57%, 62% and 58% respectively under conditions of 400 mg · m⁻³ initial concentration, 120 mm illumination distance, 1 g/350 cm² dosage of CoCuMnOx and 6 h of irradiation time by 100 W tungsten halogen lamp. Due to the competition among different VOCs, removal efficiencies in three-component mixture were reduced by 5%-26% as compared with single VOC. Degradation processes of single-component VOC and three-component VOCs both fitted pseudo first order reaction kinetics, and kinetic constants of toluene, ethyl acetate and acetone were 0.002, 0.002 8 and 0.002 33 min⁻¹ respectively under single-component condition. Reaction rates of VOCs in three-component mixture were 0.49-0.88 times of single components.

Characterization of Volatile Organic Compound (VOC) Emissions at Sites of Oil Sands Extraction and Upgrading in northern Alberta

Science.gov (United States)

Marrero, J.; Simpson, I. J.; Meinardi, S.; Blake, D. R.

2011-12-01

The crude oil reserves in Canada's oil sands are second only to Saudi Arabia, holding roughly 173 billion barrels of oil in the form of bitumen, an unconventional crude oil which does not flow and cannot be pumped without heating or dilution. Oil sands deposits are ultimately used to make the same petroleum products as conventional forms of crude oil, though more processing is required. Hydrocarbons are the basis of oil, coal and natural gas and are an important class of gases emitted into the atmosphere during oil production, particularly because of their effects on air quality and human health. However, they have only recently begun to be independently assessed in the oil sands regions. As part of the 2008 ARCTAS airborne mission, whole air samples were collected in the boundary layer above the surface mining operations of northern Alberta. Gas chromatography analysis revealed enhanced concentrations of 53 VOCs (C2 to C10) over the mining region. When compared to local background levels, the measured concentrations were enhanced up to 1.1-400 times for these compounds. To more fully characterize emissions, ground-based studies were conducted in summer 2010 and winter 2011 in the oil sands mining and upgrading areas. The data from the 200 ground-based samples revealed enhancements in the concentration of 65 VOCs. These compounds were elevated up to 1.1-3000 times above background concentrations and include C2-C8 alkanes, C1-C5 alkyl nitrates, C2-C4 alkenes and potentially toxic aromatic compounds such as benzene, toluene, and xylenes.

Sampling and analytical procedures for the determination of VOCs released into air from natural and anthropogenic sources: A comparison between SPME (Solid Phase Micro Extraction) and ST (Solid Trap) methods

International Nuclear Information System (INIS)

Tassi, F.; Capecchiacci, F.; Buccianti, A.; Vaselli, O.

2012-01-01

In the present study, two sampling and analytical methods for VOC determination in fumarolic exhalations related to hydrothermal-magmatic reservoirs in volcanic and geothermal areas and biogas released from waste landfills were compared: (a) Solid Traps (STs), consisting of three phase (Carboxen B, Carboxen C and Carbosieve S111) absorbent stainless steel tubes and (b) Solid Phase Micro Extraction (SPME) fibers, composed of DiVinylBenzene (DVB), Carboxen and PolyDimethylSiloxane. These techniques were applied to pre-concentrate VOCs discharged from: (i) low-to-high temperature fumaroles collected at Vulcano Island, Phlegrean Fields (Italy), and Nisyros Island (Greece), (ii) recovery wells in a solid waste disposal site located near Florence (Italy). A glass condensing system cooled with water was used to collect the dry fraction of the fumarolic gases, in order to allow more efficient VOC absorption avoiding any interference by water vapor and acidic gases, such as SO 2 , H 2 S, HF and HCl, typically present at relatively high concentrations in these fluids. Up to 37 organic species, in the range of 40–400 m/z, were determined by coupling gas chromatography to mass spectrometry (GC–MS). This study shows that the VOC compositions of fumaroles and biogas determined via SPME and ST are largely consistent and can be applied to the analysis of VOCs in gases released from different natural and anthropogenic environments. The SPME method is rapid and simple and more appropriate for volcanic and geothermal emissions, where VOCs are present at relatively high concentrations and prolonged gas sampling may be hazardous for the operator. The ST method, allowing the collection of large quantities of sample, is to be preferred to analyze the VOC composition of fluids from diffuse emissions and air, where these compounds are present at relatively low concentrations.

Upstream petroleum industry glycol dehydrator benzene emissions status report

International Nuclear Information System (INIS)

1999-07-01

The population of dehydrators referred to are located in the Western Sedimentary Basin in northeast British Columbia, Alberta and Saskatchewan, and includes units installed at wellsites, compressor stations, gas plants, central crude oil treating facilities, and reservoir or salt cavern gas storage facilities. Benzene emissions from the still column vent on glycol dehydrators occur as a result of glycol's strong affinity for aromatic hydrocarbons, including benzene. A study was carried out to: 1) develop a list of oil and gas companies operating in Canada, 2) develop an equipment and benzene emissions inventory of glycol dehydrators, 3) develop a database in Microsoft Access format to gather and maintain inventory and emission data, 4) evaluate and validate at least 10% of the reported data, 5) develop a list of companies that manufacture dehydrators and incinerators to determine how many new dehydrators were sold for use in Canada in 1998, and 6) prepare a report summarizing findings and recommendations. The companies included in the survey were the oil and gas companies identified by the Nickels' Oil and Gas Index and others provided by CAPP, CGA, and SEPAC. The project was carried out to gather glycol dehydrator equipment and still column vent benzene emissions information. 8 refs

Volatile organic compounds (VOCs) source profiles of on-road vehicle emissions in China.

Science.gov (United States)

Hong-Li, Wang; Sheng-Ao, Jing; Sheng-Rong, Lou; Qing-Yao, Hu; Li, Li; Shi-Kang, Tao; Cheng, Huang; Li-Ping, Qiao; Chang-Hong, Chen

2017-12-31

Volatile Organic Compounds (VOCs) source profiles of on-road vehicles were widely studied as their critical roles in VOCs source apportionment and abatement measures in megacities. Studies of VOCs source profiles from on-road motor vehicles from 2001 to 2016 were summarized in this study, with a focus on the comparisons among different studies and the potential impact of different factors. Generally, non-methane hydrocarbons dominated the source profile of on-road vehicle emissions. Carbonyls, potential important components of vehicle emission, were seldom considered in VOCs emissions of vehicles in the past and should be paid more attention to in further study. VOCs source profiles showed some variations among different studies, and 6 factors were extracted and studied due to their impact to VOCs source profile of on-road vehicles. Vehicle types, being dependent on engine types, and fuel types were two dominant factors impacting VOCs sources profiles of vehicles. In comparison, impacts of ignitions, driving conditions and accumulated mileage were mainly due to their influence on the combustion efficiency. An opening and interactive database of VOCs from vehicle emissions was critically essential in future, and mechanisms of sharing and inputting relative research results should be formed to encourage researchers join the database establishment. Correspondingly, detailed quality assurance and quality control procedures were also very important, which included the information of test vehicles and test methods as detailed as possible. Based on the community above, a better uncertainty analysis could be carried out for the VOCs emissions profiles, which was critically important to understand the VOCs emission characteristics of the vehicle emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

KAUST Repository

Sapsanis, Christos

2015-07-24

A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

The VOC-Ozone connection: a grassland case study

Science.gov (United States)

Wohlfahrt, G.; Hoertnagl, L.; Bamberger, I.; Schnitzhofer, R.; Dunkel, J.; Hammerle, A.; Graus, M.; Hansel, A.

2009-04-01

Trophospheric ozone (O3) is formed in the presence of sunlight through the interaction of volatile organic compounds (VOCs) and NOx (NO, NO2). O3 damages plants in several ways, most importantly by reducing net photosynthesis and growth. The extent of this damage depends on the time-integrated absorbed O3 flux (i.e. the dose), which is a function of leaf stomatal conductance and ambient O3 concentration, and further influenced by plant species specific defence mechanisms. VOCs are produced by plants through a variety of pathways and in response to a large number of different driving forces. A large variety of VOCs are emitted by plants in response to stress conditions, including the foliar uptake of O3. Here we present preliminary data from an ongoing study where concurrent measurements of the fluxes of VOCs and O3 are made above a managed mountain grassland in Tyrol/Austria. Fluxes of several different VOCs and O3 are measured by means of the eddy covariance method and a proton transfer reaction mass spectrometer (PTR-MS) and an ozone analyser, respectively. Our findings show that the Methanol (MeOH) flux is correlated with the daily time-integrated O3 uptake by vegetation (integrated daily from sunrise - a surrogate for the O3 dose absorbed and the oxidative stress experienced by plants) - MeOH deposition and emission prevailing at low and high time-integrated O3 uptake rates, respectively. Fluxes of other VOCs were not related to the time-integrated O3 uptake. Integrated over longer time scales (several weeks) no correlation between the O3 uptake and MeOH emissions were found. Our study thus confirms earlier leaf-level studies, who found that MeOH emission increase with O3 dose, at the ecosystems scale. As the reaction with the hydroxyl radical (OH), which is responsible for the destruction of the greenhouse gas methane (CH4), is the major sink of atmospheric MeOH, this process provides a potentially important indirect radiative forcing.

Photocatalysts: ambient temperature destruction of VOCs

Energy Technology Data Exchange (ETDEWEB)

Miller, R [IT Corp., Oak Ridge, TN (United States)

1994-12-31

Photocatalysis was a failure as a solar energy driven organic synthesis technique, but as this study indicates, it has undergone a renaissance as a promising treatment method for volatile organic compounds (VOCs) in air streams. Photocatalytic oxidation (PCO) relies upon the ability of certain semiconductors to be stimulated by UV radiation. UV light excites valence band electrons in the semiconductor catalyst to jump to a conductance band leaving holes in the valence band. The electrons and holes can react with compounds such as organic contaminants present in an air stream. Hallmarks of the technology include rapid destruction kinetics for many VOCs at ambient temperature and efficient use energy in the form of UV-A photons. Studies clearly indicate that PCO is competitive on capital cost and offers significant operating cost savings on selected applications. 6 refs., 3 tabs., 2 figs.

Photocatalysts: ambient temperature destruction of VOCs

International Nuclear Information System (INIS)

Miller, R.

1994-01-01

Photocatalysis was a failure as a solar energy driven organic synthesis technique, but as this study indicates, it has undergone a renaissance as a promising treatment method for volatile organic compounds (VOCs) in air streams. Photocatalytic oxidation (PCO) relies upon the ability of certain semiconductors to be stimulated by UV radiation. UV light excites valence band electrons in the semiconductor catalyst to jump to a conductance band leaving holes in the valence band. The electrons and holes can react with compounds such as organic contaminants present in an air stream. Hallmarks of the technology include rapid destruction kinetics for many VOCs at ambient temperature and efficient use energy in the form of UV-A photons. Studies clearly indicate that PCO is competitive on capital cost and offers significant operating cost savings on selected applications. 6 refs., 3 tabs., 2 figs

[Myelofibrosis in a benzene-exposed cleaning worker].

Science.gov (United States)

Bausà, Roser; Navarro, Lydia; Cortès-Franch, Imma

Long-term exposure to benzene has been associated with several blood malignancies, including aplastic anemia, myeloproliferative neoplasms, and different leukemias. We present a case of primary myelofibrosis in a 59-year-old woman who worked as a cleaner at a car dealership and automobile mechanic shop. For 25 years, she used gasoline as a degreaser and solvent to clean engine parts, floors and work desks on a daily basis. She was referred by her primary care provider to the Occupational Health Unit of Barcelona to assess whether her illness was work-related. Review of her job history and working conditions revealed chronic exposure to benzene in the absence of adequate preventive measures. An association between benzene exposure and myeloproliferative disease was established, suspicious for an occupational disease. Copyright belongs to the Societat Catalana de Salut Laboral.

MEMBRANE BIOTREATMENT OF VOC-LADEN AIR

Science.gov (United States)

The paper discusses membrane biotreatment of air laden with volatile organic compounds (VOCs). Microporous flat-sheet and hollow-fiber membrane contactors were used to support air-liquid mass transfer interfaces. These modules were used in a two-step process to transfer VOCs fr...

Velocity-dependent emission factors of benzene, toluene and C 2-benzenes of a passenger car equipped with and without a regulated 3-way catalyst

Science.gov (United States)

Heeb, Norbert V.; Forss, Anna-Maria; Bach, Christian; Mattrel, Peter

Time-resolved chemical ionization mass spectrometry (CI-MS) has been used to investigate the velocity-dependent emission factors for benzene, toluene, the C 2-benzenes (xylenes and ethyl benzene) and nitrogen monoxide of a gasoline-driven passenger car (1.4 l, model year 1995) driven with or without catalytic exhaust gas treatment. A set of seven different driving cycles - including the European Driving Cycle (EDC), the US Urban (FTP 75) and the Highway driving cycles - with a total driving time of 12,000 s have been studied. From the obtained emission data, two sets of 15,300 and 17,200 data points which represent transient driving in the velocity range of 0-150 km h -1 and in an acceleration window of -2-3 m s -2 were explored to gain velocity-dependent emission factors. The passenger car, equipped with a regulated rhodium-platinum based three-way catalyst, showed optimal conversion efficiency (>95%) for benzene in the velocity range of 60-120 km h -1. The conversion of benzene was reduced (speed and engine load (>130 km h -1). Whereas the conversion efficiency for the class of C 2-benzenes was reduced to 10%, no net conversion could be found for toluene and benzene when driven above 130 km h -1. In contrast, the benzene and toluene emissions exceeded those of the untreated exhaust gas in the velocity range of 130-150 km h -1 by 50-92% and by 10-34%, respectively. Thus, benzene and toluene were formed across the examined three-way catalyst if the engine is operated for an extended time in a fuel-rich mode (lambda<1).

Benzene formation in electronic cigarettes.

Directory of Open Access Journals (Sweden)

James F Pankow

Full Text Available The heating of the fluids used in electronic cigarettes ("e-cigarettes" used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen from e-cigarette fluids containing propylene glycol (PG, glycerol (GL, benzoic acid, the flavor chemical benzaldehyde, and nicotine.Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice, and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG and glycerol (GL, and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

Ambient Volatile Organic Compounds (VOCs) pollution in Isolo ...

African Journals Online (AJOL)

The adsorbed VOCs were desorbed with carbondisulphide (CS2) and the solution analysed using Gas Chromatography (GC) fitted with Flame Ionization Detector (FID). The results from analysis of the air samples collected showed that twenty-six (26) VOCs were captured in Isolo Industrial area. The VOCs were classified ...

VOC Control in Kraft Mills; FINAL

International Nuclear Information System (INIS)

Zhu, J.Y.; Chai, X.-S.; Edwards, L.L.; Gu, Y.; Teja, A.S.; Kirkman, A.G.; Pfromm, P.H.; Rezac, M.E.

2001-01-01

The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, combined with computerized mass and energy balances. Four kraft mill case studies (a continuous digester, two brownstock washing lines, and a pre-evaporator system) are presented and compared with mill measurements. These case studies provide valuable, technical information for issues related to MACT I and MACT II compliance, such as condensate collection and Clean-Condensate-Alternatives (CCA)

Synthesis of disodium [benzene-U-{sup 14}C]-(4-chlorophenylthio)methylenediphosphonate, [benzene-U-{sup 14}C]-tiludronate

Energy Technology Data Exchange (ETDEWEB)

Burgos, Alain; Ellames, G.J. [Alnwick Research Centre (United Kingdom). Dept. of Metabolism and Pharmacokinetics

1995-12-31

Disodium [benzene-U-{sup 14}C]-(4-chlorophenylithio)methylenediphosphonate, [benzene-{sup 14}C]-Tiludronate, 2, has been prepared in six steps from [benzene-U-{sup 14}C]-acetanilide in an overall radiochemical yield of 41%. A key step in this transformation was the efficient conversion of [U-{sup 14}C]-4-chloroaniline to [benzene-U-{sup 14}C]-4-chlorophenylthiocyanate, 5, in 83% yield by treatment of the corresponding diazonium salt, 9 with iron(111) thiocyanate. It should be noted that formation of the isomeric [benzene-U-{sup 14}C]-4-chlorophenylisothiocyanate, 11, as a byproduct, was observed in only {approx} 1% yield. (author).

The effect of wet film thickness on VOC emissions from a finishing varnish.

Science.gov (United States)

Lee, Shun-Cheng; Kwok, Ngai-Hong; Guo, Hai; Hung, Wing-Tat

2003-01-20

Finishing varnishes, a typical type of oil-based varnishes, are widely used to shine metal, wood trim and cabinet surfaces in Hong Kong. The influence of wet film thickness on volatile organic compound (VOC) emissions from a finishing varnish was studied in an environmental test chamber. The varnish was applied on an aluminium foil with three different wet film thickness (35.2, 69.9 and 107.3 microm). The experimental conditions were 25.0 degrees C, 50.0% relative humidity (RH) with an air exchange rate of 0.5 h(-1). The concentrations of the major VOCs were monitored for the first 10 h. The air samples were collected by canisters and analysed by gas chromatography/mass selective detector (GC/MSD). Six major VOCs including toluene, chlorobenzene, ethylbenzene, m,p-xylene, o-xylene and 1,3,5-trimethylbenzene were identified and quantified. Marked differences were observed for three different film thicknesses. VOC concentrations increased rapidly during the first few hours and then decreased as the emission rates declined. The thicker the wet film, the higher the VOC emissions. A model expression included an exponentially decreasing emission rate of varnish film. The concentration and time data measured in the chamber were used to determine the parameters of empirical emission rate model. The present work confirmed that the film thickness of varnish influenced markedly the concentrations and emissions of VOCs. Copyright 2002 Elsevier Science B.V.

VOC emissions chambers

Data.gov (United States)

Federal Laboratory Consortium — In order to support the development of test methods and reference materials for volatile organic compounds (VOC) emissions from building materials and furnishings,...

Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.

Science.gov (United States)

Huang, Binbin; Lei, Chao; Wei, Chaohai; Zeng, Guangming

2014-10-01

Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of co-mingled benzene, toluene and TCE in groundwater.

Science.gov (United States)

Chen, Liang; Liu, Yulong; Liu, Fei; Jin, Song

2014-06-30

This work addressed a hypothetical but practical scenario that includes biological oxidation and reductive dechlorination in treating groundwater containing co-mingled plume of trichloroethene (TCE), benzene and toluene. Groundwater immediately downgradient from the commonly used zero-valent iron (ZVI) has shown alkaline pH (up to 10.7). The elevated pH may influence BTEX compounds (i.e., benzene, toluene, ethyl benzene, and xylenes) biodegradation, which could also be inhibited by elevated concentrations of TCE. Data from this work suggests that the inhibition coefficients (IC) value for 100 μg/L and 500 μg/L of TCE on benzene and toluene degradation are 2.1-2.8 at pH 7.9, and 3.5-6.1 at pH 10.5. For a co-mingled plume, it appears to be more effective to reduce TCE by ZVI before addressing benzene and toluene biodegradation. The ample buffering capacity of most groundwater and the adaptation of benzene and toluene-degrading microbes are likely able to eliminate the adverse influence of pH shifts downgradient from a ZVI-PRB. Copyright © 2014 Elsevier B.V. All rights reserved.

Benzene and lymphohematopoietic malignancies in humans.

Science.gov (United States)

Hayes, R B; Songnian, Y; Dosemeci, M; Linet, M

2001-08-01

Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.

Economical benzene emission reduction

International Nuclear Information System (INIS)

Schuetz, R.

1999-01-01

Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

Plant communication: mediated by individual or blended VOCs?

Science.gov (United States)

Ueda, Hirokazu; Kikuta, Yukio; Matsuda, Kazuhiko

2012-02-01

Plants emit volatile organic compounds (VOCs) as a means to warn other plants of impending danger. Nearby plants exposed to the induced VOCs prepare their own defense weapons in response. Accumulated data supports this assertion, yet much of the evidence has been obtained in laboratories under artificial conditions where, for example, a single VOC might be applied at a concentration that plants do not actually experience in nature. Experiments conducted outdoors suggest that communication occurs only within a limited distance from the damaged plants. Thus, the question remains as to whether VOCs work as a single component or a specific blend, and at which concentrations VOCs elicit insect and pathogen defenses in undamaged plants. We discuss these issues based on available literature and our recent work, and propose future directions in this field.

Benzene exposures in urban areas

International Nuclear Information System (INIS)

Valerio, F.; Pala, M.; Cipolla, M.; Stella, A.

2001-01-01

Benzene exposures in urban areas were reviewed. Available data confirm that both in USA and Europe, benzene concentrations measured by fixed outdoor monitoring stations underestimate personal exposures of urban residents. Indoor sources, passive smoke and the high exposures during commuting time may explain this difference. Measures in European towns confirm that very frequently mean daily personal exposures to benzene exceed 10 μg/m 3 , current European air quality guideline for this carcinogenic compound [it

A DFT study of volatile organic compounds adsorption on transition metal deposited graphene

Energy Technology Data Exchange (ETDEWEB)

Kunaseth, Manaschai, E-mail: manaschai@nanotec.or.th [Nanoscale Simulation Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120 (Thailand); Poldorn, Preeyaporn [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand); Junkeaw, Anchalee; Meeprasert, Jittima; Rungnim, Chompoonut; Namuangruk, Supawadee [Nanoscale Simulation Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120 (Thailand); Kungwan, Nawee [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Inntam, Chan [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand); Jungsuttiwong, Siriporn, E-mail: siriporn.j@ubu.ac.th [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand)

2017-02-28

Highlights: • VOCs removal via modified carbon-based adsorbent using density functional theory. • The single-vacancy defective graphene (SDG) with metal-deposited significantly increase the adsorption efficiency. • TM-doped SDG is a suitable adsorbent material for VOC removal. • Electron in hybridized sp{sup 2}-orbitals of heteroatoms has an effect on mode of adsorption. - Abstract: Recently, elevated global emission of volatile organic compounds (VOCs) was associated to the acceleration and increasing severity of climate change worldwide. In this work, we investigated the performance of VOCs removal via modified carbon-based adsorbent using density functional theory. Here, four transition metals (TMs) including Pd, Pt, Ag, and Au were deposited onto single-vacancy defective graphene (SDG) surface to increase the adsorption efficiency. Five prototypical VOCs including benzene, furan, pyrrole, pyridine, and thiophene were used to study the adsorption capability of metal-deposited graphene adsorbent. Calculation results revealed that Pd, Pt, Au, and Ag atoms and nanoclusters bind strongly onto the SDG surface. In this study, benzene, furan and pyrrole bind in the π-interaction mode using delocalized π-electron in aromatic ring, while pyridine and thiophene favor X- interaction mode, donating lone pair electron from heteroatom. In terms of adsorption, pyridine VOC adsorption strengths to the TM-cluster doped SDG surfaces are Pt{sub 4} (−2.11 eV) > Pd{sub 4} (−2.05 eV) > Ag{sub 4} (−1.53 eV) > Au{sub 4} (−1.87 eV). Our findings indicate that TM-doped SDG is a suitable adsorbent material for VOC removal. In addition, partial density of states analysis suggests that benzene, furan, and pyrrole interactions with TM cluster are based on p-orbitals of carbon atoms, while pyridine and thiophene interactions are facilitated by hybridized sp{sup 2}-orbitals of heteroatoms. This work provides a key insight into the fundamentals of VOCs adsorption on carbon

Benzene in Canadian gasoline : report on the effect of the benzene in gasoline regulations 2002

Energy Technology Data Exchange (ETDEWEB)

Guthrie, J. [Environment Canada, Ottawa, ON (Canada); Sabourin, R. [Carleton Univ., Ottawa, ON (Canada); Brunet, E. [Waterloo Univ., ON (Canada)

2003-11-01

The response of primary suppliers to Benzene in Gasoline Regulations was reviewed, and a summary of the effects of those regulations on the composition of gasoline in Canada in 2002 was offered. These regulations, effective July 1, 1999, were designed to provide a new approach to control fuel composition. It allowed suppliers, as a basis for compliance, the option to elect to use a yearly pool average. The benzene emission number (BEN) of gasoline was regulated, and a limit imposed on a per-litre limit for benzene at point of sale. The results indicated that reported benzene levels were significantly reduced, while aromatic levels remained practically unchanged from 1994. Since 1998, rural ambient benzene concentrations decreased by more than 32 per cent, while in urban areas, they decreased by 47 per cent over the same period. The regulated requirements for benzene concentration were met by primary suppliers in Canada in 2002 (with one exception), as were BEN levels. A number of instances of non-compliance with laboratory procedures were discovered during independent audits required for those suppliers who elected to be on on a yearly pool average. Corrective action designed to address these issues was implemented. 41 tabs., 24 figs.

Toxicity assessment of volatile organic compounds and polycyclic aromatic hydrocarbons in motorcycle exhaust.

Science.gov (United States)

Chang, Chang-Tang; Chen, Bor-Yann

2008-05-30

This study investigates the toxicity of various pollutant species from motorcycle exhaust via dose-response analysis and margin of safety using Escherichia coli DH5 alpha. The toxicity evaluation of the major components of motorcycle exhaust volatile organic compounds (VOCs), collected with impinger, and polycyclic aromatic hydrocarbons (PAHs), collected with filter and XAD-2, is essential to determine emission standards for motorcycles. The toxicity of benzene (B), toluene (T), ethyl benzene (E) and xylene (X) was selected for comparison as standard VOCs emitted from motorcycles. In addition, three types of reformulated gasoline (high oxygenate and high benzene content (No. 1), low oxygen and high benzene (No. 2), and low oxygen and low benzene (No. 3) were prepared to reveal combined toxicity of individual compositions. Motorcycle exhaust is significantly more toxic than BTEX due to the highly toxic VOCs generated from incomplete combustion. Overall toxicity evaluation showed that the toxicity, indicated as EC50, was approximately as follows: PAHs>two-stroke engines>four-stroke engines>BTEX.

Toxicity assessment of volatile organic compounds and polycyclic aromatic hydrocarbons in motorcycle exhaust

International Nuclear Information System (INIS)

Chang, C.-T.; Chen, B.-Y.

2008-01-01

This study investigates the toxicity of various pollutant species from motorcycle exhaust via dose-response analysis and margin of safety using Escherichia coli DH5α. The toxicity evaluation of the major components of motorcycle exhaust volatile organic compounds (VOCs), collected with impinger, and polycyclic aromatic hydrocarbons (PAHs), collected with filter and XAD-2, is essential to determine emission standards for motorcycles. The toxicity of benzene (B), toluene (T), ethyl benzene (E) and xylene (X) was selected for comparison as standard VOCs emitted from motorcycles. In addition, three types of reformulated gasoline (high oxygenate and high benzene content (No. 1), low oxygen and high benzene (No. 2), and low oxygen and low benzene (No. 3) were prepared to reveal combined toxicity of individual compositions. Motorcycle exhaust is significantly more toxic than BTEX due to the highly toxic VOCs generated from incomplete combustion. Overall toxicity evaluation showed that the toxicity, indicated as EC 50 , was approximately as follows: PAHs > two-stroke engines > four-stroke engines > BTEX

Progress of epidemiological and molecular epidemiological studies on benzene in China.

Science.gov (United States)

Li, Guilan; Yin, Songnian

2006-09-01

Benzene is an organic solvent that has been used in industry for about 100 years throughout the world. Since 1973, a series of toxicological and molecular epidemiological studies on benzene were conducted by researchers at the Chinese Academy of Preventive Medicine (CAPM) (1973-1986) and subsequently by a collaboration between the CAPM and the National Cancer Institute (NCI) in the United States that began in 1986, which was joined by investigators from the University of California at Berkeley, the University of North Carolina at Chapel Hill, and New York University. The findings demonstrated that the risk of leukemia and lymphoma among benzene-exposed workers was significantly increased, with elevated risks for leukemia present not only at higher exposure but also among workers exposed to under 10 ppm. Therefore, the benzene permissible level was decreased to 1.8 ppm (6 mg/m(3)) and benzene-induced leukemia is treated as an occupational cancer in China. The benzene permissible level is 1.0 in the United States and in several other developed countries and it has been suggested to be decreased to 0.5 ppm (ACGIH). A number of potential biomarkers are related to benzene exposure and poisoning. Some of these are benzene oxide-protein adducts, chromosome aberration of lymphocytes, and GPA mutations in erythrocytes, a decrease in B cell and CD4(-)T cell counts in peripheral blood, and altered expression of CXCL16, ZNF331, JUN, and PF4 in lymphocytes. Variation in multiple benzene metabolizing genes may be associated with risk of benzene hematotoxicity, including CYP2E1, MPO, NQO1, and GSTT1.

Effects of trace volatile organic compounds on methane oxidation

Directory of Open Access Journals (Sweden)

Chiemchaisri Wilai

2001-01-01

Full Text Available The effects of volatile organic compounds (VOCs on methane oxidation in landfill cover soils were examined. The batch experiments were conducted using single and mixed VOCs, such as, dichloromethane (DCM, trichloroethylene (TCE, tetrachloroethylene (PCE, and benzene. The results from all combinations showed a decrease in methane oxidation rate with increase in VOC concentrations. Moreover, inhibition effects of TCE and DCM were found higher than benzene and PCE. The reduction of methane oxidation by benzene and PCE could be attributed to the toxicity effect, whereas TCE and DCM were found to exhibit the competitive-inhibition effect. When the soil was mixed with DCM, no methane oxidation was found. Damage to the cell's internal membrane was found in a methanotrophic culture exposed to VOC gases which is the attachment site of a key enzyme needed for methane oxidation

Elevated Atmospheric Levels of Benzene and Benzene-Related Compounds from Unconventional Shale Extraction and Processing: Human Health Concern for Residential Communities.

Science.gov (United States)

Rich, Alisa L; Orimoloye, Helen T

2016-01-01

The advancement of natural gas (NG) extraction across the United States (U.S.) raises concern for potential exposure to hazardous air pollutants (HAPs). Benzene, a HAP and a primary chemical of concern due to its classification as a known human carcinogen, is present in petroleum-rich geologic formations and is formed during the combustion of bypass NG. It is a component in solvents, paraffin breakers, and fuels used in NG extraction and processing (E&P). The objectives of this study are to confirm the presence of benzene and benzene-related compounds (benzene[s]) in residential areas, where unconventional shale E&P is occurring, and to determine if benzene[s] exists in elevated atmospheric concentrations when compared to national background levels. Ambient air sampling was conducted in six counties in the Dallas/Fort Worth Metroplex with passive samples collected in evacuated 6-L Summa canisters. Samples were analyzed by gas chromatography/mass spectrometry, with sampling performed at variable distances from the facility fence line. Elevated concentrations of benzene[s] in the atmosphere were identified when compared to U.S. Environmental Protection Agency's Urban Air Toxics Monitoring Program. The 24-hour benzene concentrations ranged from 0.6 parts per billion by volume (ppbv) to 592 ppbv, with 1-hour concentrations from 2.94 ppbv to 2,900.20 ppbv. Benzene is a known human carcinogen capable of multisystem health effects. Exposure to benzene is correlated with bone marrow and blood-forming organ damage and immune system depression. Sensitive populations (children, pregnant women, elderly, immunocompromised) and occupational workers are at increased risk for adverse health effects from elevated atmospheric levels of benzene[s] in residential areas with unconventional shale E&P.

Volatile Organic Compound (VOC) Emissions from Dairy Cows and Their Waste

Science.gov (United States)

Shaw, S.; Holzinger, R.; Mitloehner, F.; Goldstein, A.

2005-12-01

Biogenic VOCs are typically defined as those directly emitted from plants, but approximately 6% of global net primary production is consumed by cattle that carry out enteric fermentation and then emit VOCs that could also be considered biogenic. Current regulatory estimates suggest that dairy cattle in central California emit VOCs at rates comparable to those from passenger vehicles in the region, and thus contribute significantly to the extreme non-attainment of ozone standards there. We report PTR-MS measurements of ammonia and VOCs, and cavity-enhanced-absorption gas analyzer (Los Gatos Research, Inc.) measurements of CH4, emitted from dairy cattle in various stages of pregnancy/lactation and their waste. Experiments were conducted in chambers at UC Davis that simulate freestall cow housing conditions. CH4 fluxes ranged from 125-374 lb/cow/year. The compounds with the highest fluxes from '3 cows+waste' treatments were: ammonia (1-18), methanol (0-2.3), acetone+propanal (0.2-0.7), dimethylsulfide (0-0.4), and mass 109 (likely ID = p-cresol; 0-0.3) in lb/cow/year. Mass 60 (likely ID = trimethylamine) and acetic acid were also abundant. There were 10s of additional compounds with detectable, but small, emissions. A few compounds that were likely emitted (i.e. ethanol, formaldehyde, and dimethylamine) were not quantified by the PTR-MS. The total flux for all measured organic gases (TOG = CH4 + PTR-MS VOCs(including acetone+propanal)) averaged 246±45 lb/cow/year for '3 cows+waste' treatments, and was dominated by methane (>98%). TOG flux for 'waste only' treatments averaged 1.1±0.1 lb/cow/year, and was instead dominated by VOC (>84%). The PTR-MS VOCs as a percent of TOG (0.6±0.2%) emitted from '3 cows+waste' treatments in chamber conditions was a factor of 10 smaller than that currently estimated by the California Air Resources Board. In addition, the ozone forming potentials of the most abundant VOCs are only about 10% those of typical combustion or plant

An updated emission inventory of vehicular VOCs and IVOCs in China

Science.gov (United States)

Liu, Huan; Man, Hanyang; Cui, Hongyang; Wang, Yanjun; Deng, Fanyuan; Wang, Yue; Yang, Xiaofan; Xiao, Qian; Zhang, Qiang; Ding, Yan; He, Kebin

2017-10-01

Currently, the emission inventory of vehicular volatile organic compounds (VOCs) is one of those with the largest errors and uncertainties due to suboptimal estimation methods and the lack of first-hand basic data. In this study, an updated speciated emission inventory of VOCs and an estimation of intermediate-volatility organic compounds (IVOCs) from vehicles in China at the provincial level for the year of 2015 are developed based on a set of state-of-the-art methods and an abundance of local measurement data. Activity data for light-duty vehicles are derived from trajectories of more than 70 000 cars for 1 year. The annual mileage of trucks are calculated from reported data by more than 2 million trucks in China. The emission profiles are updated using measurement data. Vehicular tailpipe emissions (VTEs) and four types of vehicular evaporation emissions (VEEs), including refueling, hot soak, diurnal and running loss, are taken into account. Results show that the total vehicular VOC emissions in China are 4.21 Tg (with a 95 % confidence interval range from 2.90 to 6.54 Tg) and the IVOC emissions are 200.37 Gg in 2015. VTEs are still the predominant contributor, while VEEs are responsible for 39.20 % of VOC emissions. The control of VEEs is yet to be optimized in China. Among VTEs, passenger vehicles emissions have the largest share (49.86 %), followed by trucks (28.15 %) and motorcycles (21.99 %). Among VEEs, running loss is the largest contributor (81.05 %). For both VTEs and VEEs, Guangdong, Shandong and Jiangsu province are three of the highest, with a respective contribution of 10.66, 8.85 and 6.54 % to the total amounts of VOCs from vehicles. 97 VOC species are analyzed in this VOC emission inventory. i-Pentane, toluene and formaldehyde are found to be the most abundant species in China's vehicular VOC emissions. The estimated IVOCs are another inconvenient truth, concluding that precursor emissions for secondary organic aerosol (SOA) from vehicles are much

Contrasting VOC Composition in London, UK and Beijing, China

Science.gov (United States)

Dunmore, R.; Hopkins, J. R.; Shaw, M.; Squires, F. A.; Lee, J. D.; Lewis, A. C.; Hamilton, J. F.

2017-12-01

With an increasing fraction of the world's population now living in megacities, urban air quality in those locations has the potential to be one of the largest controllable factors for public health. Both London and Beijing are classified as megacities, with the latter almost twice as densely populated. The key drivers and trajectory of air pollution are unique to each location; London has substantially reduced PM10 concentrations over the past two decades but continues to have high urban NO2. Beijing has had well-reported high levels of PM, is now in a phase of gradual decline, and has proportionately low NO2. Both locations however, continue to emit a mix of gas phase pollutants with the potential to form photochemical ozone. Whilst the abundance of NOx in each city is relatively straightforward to quantify, the VOC mixtures that are present differ between these two cities and this has consequential impacts on the downwind ozone formation potential. This work reports a comprehensive assessment of VOC speciation, reactivity and abundance in the two cities using a common set of inter-comparable measurement approaches. Hourly observations of VOCs over the range C2 - C13+ were made using two gas chromatography (GC) instruments; a PLOT column based GC for the most volatile fraction (C2-C7) and a comprehensive two-dimensional GC (GCxGC) for VOCs with more than 7 carbons. London has atmospheric VOC concentrations that in mass and reactivity terms are dominated by longer chain VOCs from diesel fuel. The VOC mixture in ambient Beijing air is dominated by short chain VOCs, a mix of both alkenes from incomplete combustion sources and alkanes and aromatics from petrochemical sources. The substantial difference in the fleet proportions of gasoline and diesel powered vehicles between the two cities is clearly reflected in ambient VOCs. In summertime, isoprene was a notable contributor to VOC reactivity in both cities despite both being highly urbanised locations. The absolute

Current understandings and perspectives on non-cancer health effects of benzene: A global concern

Energy Technology Data Exchange (ETDEWEB)

Bahadar, Haji [International Campus, Tehran University of Medical Sciences (Iran, Islamic Republic of); Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Mostafalou, Sara [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: Mohammad.Abdollahi@UToronto.Ca [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of)

2014-04-15

Objective: Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. Methodology: A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of “benzene toxic health effects”, “environmental volatile organic compounds”, “diabetes mellitus and environmental pollutants”, “breast cancer and environmental pollution”, “prevalence of lung cancer”, and “diabetes prevalence”. More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. Results: Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. Conclusion: Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up. - Highlights: • Benzene is a volatile organic compound and established blood carcinogen. • Exposure to benzene needs to be

Ambient volatile organic compounds (VOCs) in Calgary, Alberta: Sources and screening health risk assessment.

Science.gov (United States)

Bari, Md Aynul; Kindzierski, Warren B

2018-08-01

Exposure to ambient volatile organic compound (VOCs) in urban areas is of interest because of their potential chronic and acute adverse effects to public health. Limited information is available about VOC sources in urban areas in Canada. An investigation of ambient VOCs levels, their potential sources and associated risks to public health was undertaken for the urban core of Alberta's largest city (downtown Calgary) for the period 2010-2015. Twenty-four hour arithmetic and geometric mean concentrations of total VOCs were 42μg/m 3 and 39μg/m 3 , respectively and ranged from 16 to 160μg/m 3 , with winter levels about two-fold higher than summer. Alkanes (58%) were the most dominant compounds followed by halogenated VOCs (22%) and aromatics (11%). Mean and maximum 24h ambient concentrations of selected VOCs of public health concern were below chronic and acute health risk screening criteria of the United States regulatory agencies and a cancer screening benchmark used in Alberta equivalent to 1 in 100,000 lifetime risk. The Positive matrix factorization (PMF) model revealed nine VOC sources at downtown Calgary, where oil/natural gas extraction/combustion (26%), fuel combustion (20%), traffic sources including gasoline exhaust, diesel exhaust, mixed fugitive emissions (10-15%), and industrial coatings/solvents (12%) were predominant. Other sources included dry cleaning (3.3%), biogenic (3.5%) and a background source (18%). Source-specific health risk values were also estimated. Estimated cancer risks for all sources were below the Alberta cancer screening benchmark, and estimated non-cancer risks for all sources were well below a safe level. Copyright © 2018 Elsevier B.V. All rights reserved.

Atmospheric benzene and toluene

International Nuclear Information System (INIS)

Rasmussen, R.A.; Khalil, M.A.K.

1983-01-01

Atmospheric concentrations of benzene (C 6 H 6 ) and toluene (C 7 H 8 )have been observed at nine remote locations of the world ranging in latitude from inside the arctic circle to the south pole. The observations span all seasons at each location. In the northern hemisphere it is observed that C 6 H 6 and C 7 H 8 are most abundant during winter and least abundant during summer. Based on the limited data available, such cycles are not observed in the tropics. These findings are consistent with the expected latitudinal and seasonal variations of OH radicals which cause benzene and toluene to be removed from the atmosphere. The latitude distribution shows high concentrations at mid latitude and low levels in the southern hemisphere. This finding is consistent with the present understanding that the sources of benzene and toluene are primarily anthropogenic. The observed concentration distribution and varibility are consistent with the short expected atmospheric lifetime of the order of months for benzene and days for toluene

The influence of different light quality and benzene on gene expression and benzene degradation of Chlorophytum comosum.

Science.gov (United States)

Setsungnern, Arnon; Treesubsuntorn, Chairat; Thiravetyan, Paitip

2017-11-01

Benzene, a carcinogenic compound, has been reported as a major indoor air pollutant. Chlorophytum comosum (C. comosum) was reported to be the highest efficient benzene removal plant among other screened plants. Our previous studies found that plants under light conditions could remove gaseous benzene higher than under dark conditions. Therefore, C. comosum exposure to airborne benzene was studied under different light quality at the same light intensity. C. comosum could remove 500 ppm gaseous benzene with the highest efficiency of 68.77% under Blue:Red = 1:1 LED treatments and the lowest one appeared 57.41% under white fluorescent treatment within 8 days. After benzene was uptaken by C. comosum, benzene was oxidized to be phenol in the plant cells by cytochrome P450 monooxygenase system. Then, phenol was catalyzed to be catechol that was confirmed by the up-regulation of phenol 2-monooxygenase (PMO) gene expression. After that, catechol was changed to cic, cis-muconic acid. Interestingly, cis,cis-muconic acid production was found in the plant tissues higher than phenol and catechol. The result confirmed that NADPH-cytochrome P450 reductase (CPR), cytochrome b5 (cyt b5), phenol 2-monooxygenase (PMO) and cytochrome P450 90B1 (CYP90B1) in plant cells were involved in benzene degradation or detoxification. In addition, phenol, catechol, and cis,cis-muconic acid production were found under the Blue-Red LED light conditions higher than under white fluorescent light conditions due to under LED light conditions gave higher NADPH contents. Hence, C. comosum under the Blue-Red LED light conditions had a high potential to remove benzene in a contaminated site. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

VOCs in Non-Arid Soils Integrated Demonstration: Technology summary

International Nuclear Information System (INIS)

1994-02-01

The Volatile Organic Compounds (VOCs) in Non-Arid Soils Integrated Demonstration (ID) was initiated in 1989. Objectives for the ID were to test the integrated demonstration concept, demonstrate and evaluate innovative technologies/systems for the remediation of VOC contamination in soils and groundwater, and to transfer technologies and systems to internal and external customers for use in fullscale remediation programs. The demonstration brought together technologies from DOE laboratories, other government agencies, and industry for demonstration at a single test bed. The Savannah River Site was chosen as the location for this ID as the result of having soil and groundwater contaminated with VOCS. The primary contaminants, trichlorethylene and tetrachloroethylene, originated from an underground process sewer line servicing a metal fabrication facility at the M-Area. Some of the major technical accomplishments for the ID include the successful demonstration of the following: In situ air stripping coupled with horizontal wells to remediate sites through air injection and vacuum extraction; Crosshole geophysical tomography for mapping moisture content and lithologic properties of the contaminated media; In situ radio frequency and ohmic heating to increase mobility, of the contaminants, thereby speeding recovery and the remedial process; High-energy corona destruction of VOCs in the off-gas of vapor recovery wells; Application of a Brayton cycle heat pump to regenerate carbon adsorption media used to trap VOCs from the offgas of recovery wells; In situ permeable flow sensors and the colloidal borescope to determine groundwater flow; Chemical sensors to rapidly quantify chlorinated solvent contamination in the subsurface; In situ bioremediation through methane/nutrient injection to enhance degradation of contaminants by methanotrophic bateria

(Liquid + liquid) equilibria for benzene + cyclohexane + N,N-dimethylformamide + sodium thiocyanate

International Nuclear Information System (INIS)

Dong, Hongxing; Yang, Xiaoguang; Yue, Guojun; Zhang, Wei; Zhang, Jin

2013-01-01

Graphical abstract: On the left, the figure was phase diagram about the LLE date. On the right, the figure was about the effects of mass fraction of benzene in the raffinate phase to the selectivity(S) coefficient under different salt concentration. ■, the NaSCN and DMF in ratio of 5/95; • , the NaSCN and DMF in ratio of 10/90; ▴, the NaSCN and DMF in ratio of 15/85; ★, the NaSCN and DMF in ratio of 20/80; ▾, the NaSCN and DMF in ratio of 23/77. ♦, only DMF was used extractant (the selectivity coefficient was calculated by literature 17). w 22 , refer to the mass fraction of benzene in the raffinate phase (cyclohexane-rich phase). Highlights: • (Liquid + liquid) equilibrium for quaternary system was measured. • The components include benzene, cyclohexane, N,N-dimethylformamide, sodium thiocyanate. • The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. • Separation of benzene and cyclohexane by NaSCN + DMF was discussed. -- Abstract: (Liquid + liquid) equilibrium (LLE) data for benzene + cyclohexane + N,N-dimethylformamide (DMF) + sodium thiocyanate (NaSCN) were measured experimentally at atmospheric pressure and 303.15 K. The selectivity coefficients from these LLE data were calculated and compared to those previously reported in the literature for the systems (benzene + cyclohexane + DMF) and (benzene + cyclohexane + DMF + KSCN). The NRTL equation was used to correlate the experimental data. The agreement between the predicted and experimental results was good. It was found that the selectivity coefficients of DMF + NaSCN for benzene ranged from 2.45 to 11.99. Considering the relatively high extraction capacity and selectivity for benzene, DMF + NaSCN may be used as a potential extracting solvent for the separation of benzene from cyclohexane

Critical issues in benzene toxicity and metabolism: the effect of interactions with other organic chemicals on risk assessment.

OpenAIRE

Medinsky, M A; Schlosser, P M; Bond, J A

1994-01-01

Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene are well documented and include aplastic anemia and pancytopenia. Some individuals exposed repeatedly to cytotoxic concentrations of benzene develop acute myeloblastic anemia. It has been hypothesized that metabolism of benzene is required for its toxicity, although administration of no single benzene metabolite duplicates the toxicity of benzene. Several inve...

Actual car fleet emissions estimated from urban air quality measurements and street pollution models

International Nuclear Information System (INIS)

Palmgren, F.; Berkowicz, R.; Hertel, O.; Ziv, A.

1999-01-01

A method to determine emissions from the actual car fleet under realistic driving conditions has been developed. The method is based on air quality measurements, traffic counts and inverse application of street air quality models. Many pollutants are of importance for assessing the adverse impact of the air pollution, e.g. NO 2 , CO, lead, VOCs and particulate matter. Aromatic VOCs are of special great concern due to their adverse health effects. Measurements of benzene, toluene and xylenes were carried out in central Copenhagen since 1994. Significant correlation was observed between VOCs and CO concentrations, indicating that the petrol engine vehicles are the major sources of VOC air pollution in central Copenhagen. Hourly mean concentrations of benzene were observed to reach values of up to 20 ppb, what is critically high according to the WHOs recommendations. Based on inverse model calculation of dispersion of pollutants in street canyons, an average emission factor of benzene for the fleet of petrol fuelled vehicles was estimated to be 0.38 g/km in 1994 and 0.11 in 1997. This decrease was caused by the reduction of benzene content in Danish petrol since summer 1995 and increasing percentage of cars equipped with three-way catalysts. The emission factors for benzene for diesel-fuelled vehicles were low

Enhanced in vivo IgE production and T cell polarization toward the type 2 phenotype in association with indoor exposure to VOC: results of the LARS study.

Science.gov (United States)

Lehmann, I; Rehwagen, M; Diez, U; Seiffart, A; Rolle-Kampczyk, U; Richter, M; Wetzig, H; Borte, M; Herbarth, O

2001-12-01

The association between indoor exposure to volatile organic compounds (VOC), prevalence of allergic sensitization and cytokine secretion profile of peripheral T cells was studied in 3 year old children of the LARS study (Leipzig Allergy Risk Children Study) to investigate the role of VOC exposure as a risk factor for the development of atopic disease. Indoor VOC exposure was measured over a period of 4 weeks in infants' bedrooms using a passive sampling system. Specific IgE antibodies to food, indoor and outdoor allergens were measured by the Pharmacia CAP system and correlated to VOC exposure (n = 120). In addition, cytokine producing peripheral T cells (interleukin(IL)-4, interferon(IFN)-gamma) were measured in a subgroup of 28 children by means of intracellular cytokine staining. For the first time we were able to show that exposure to alkanes (C6, C9, C10) and aromatic compounds (toluene, o-xylene, m + p-xylene, 2-, 3- and 4-ethyl-toluene, chlorobenzene) may contribute to the risk of allergic sensitization to the food allergens milk and egg white (Odds ratios between 5.7 and 11.2). Moreover, significantly reduced numbers of CD3+/CD8+ peripheral T cells were found in children exposed to alkanes (C9-C13), naphthalene and chlorobenzene. Exposure to benzene, ethylbenzene and chlorobenzene was associated with higher percentages of IL-4 producing CD3+ T cells. Both an increase in IL-4 producing type 2 T cells and a reduction of IFN-gamma producing type 1 T cells may contribute to a type 2 skewed memory in response to allergens. Therefore, we suggest exposure to VOCs in association with allergic sensitization to be mediated by a T cell polarization toward the type 2 phenotype.

Critical issues in benzene toxicity and metabolism: the effect of interactions with other organic chemicals on risk assessment.

Science.gov (United States)

Medinsky, M A; Schlosser, P M; Bond, J A

1994-11-01

Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene are well documented and include aplastic anemia and pancytopenia. Some individuals exposed repeatedly to cytotoxic concentrations of benzene develop acute myeloblastic anemia. It has been hypothesized that metabolism of benzene is required for its toxicity, although administration of no single benzene metabolite duplicates the toxicity of benzene. Several investigators have demonstrated that a combination of metabolites (hydroquinone and phenol, for example) is necessary to duplicate the hematotoxic effect of benzene. Enzymes implicated in the metabolic activation of benzene and its metabolites include the cytochrome P450 monooxygenases and myeloperoxidase. Since benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. Other organic molecules that are substrates for cytochrome P450 can inhibit the metabolism of benzene. For example, toluene has been shown to inhibit the oxidation of benzene in a noncompetitive manner. Enzyme inducers, such as ethanol, can alter the target tissue dosimetry of benzene metabolites by inducing enzymes responsible for oxidation reactions involved in benzene metabolism. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes, such as enzymatic oxidation, and deactivation processes, like conjugation and excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

High Time Resolution Measurements of VOCs from Vehicle Cold Starts: The Air Toxic Cold Start Pulse

Science.gov (United States)

Jobson, B. T.; Huangfu, Y.; Vanderschelden, G. S.

2017-12-01

Pollutants emitted during motor vehicle cold starts, especially in winter in some climates, is a significant source of winter time air pollution. While data exist for CO, NO, and total hydrocarbon emissions from federal testing procedures for vehicle emission certification, little is known about the emission rates of individual volatile organic compounds, in particular the air toxics benzene, formaldehyde, and acetaldehyde. Little is known about the VOC speciation and temperature dependence for cold starts. The US EPA vehicle emission model MOVES assumes that cold start emissions have the same speciation profile as running emissions. We examined this assumption by measuring cold start exhaust composition for 4 vehicles fueled with E10 gasoline over a temperature range of -4°C to 10°C in winter of 2015. The extra cold start emissions were determined by comparison with emissions during engine idling. In addition to CO and NOx measurements a proton transfer reaction mass spectrometer was used to measure formaldehyde, acetaldehyde, benzene, toluene, and C2-alkylbenzenes at high time resolution to compare with the cold start emission speciation profiles used in the EPA MOVES2014 model. The results show that after the vehicle was started, CO mixing ratios can reach a few percent of the exhaust and then drop to several ppmv within 2 minutes of idling, while NOx showed different temporal behaviors among the four vehicles. VOCs displayed elevated levels during cold start and the peak mixing ratios can be two orders higher than idling phase levels. Molar emission ratios relative to toluene were used to compare with the emission ratio used in MOVES2014 and we found the formaldehyde-to-toluene emission ratio was about 0.19, which is 5 times higher than the emission ratio used in MOVES2014 and the acetaldehyde-to-toluene emission ratios were 0.86-0.89, which is 8 times higher than the ones in MOVES2014. The C2-alkylbenzene-to-toluene ratio agreed well with moves. Our results

Development of aromatic VOC control technology by electron beam hybrid

International Nuclear Information System (INIS)

Kim, Jo-Chun; Kim, Ki-Joon

2006-01-01

As a fundamental study, the decomposition of volatile organic compounds (VOCs) using electron beam (EB) irradiation has been extensively investigated. EB treatments of VOCs such as toluene and styrene are discussed. The degradation characteristics were intensively investigated under various concentrations and irradiation doses to determine and improve VOC removal efficiencies. This work illustrates that the removal efficiencies of aromatic VOCs generally increase as their concentrations decrease and the irradiation doses increase. Based on these basic studies, it was found that by-products produced from EB irradiation of VOCs would cause a secondary pollution problem. Therefore, a novel hybrid technology has been applied to control aromatic VOC emissions by annexing the catalyst technique with conventional treatment study using EB technology. The experiments were carried out using a bench-scale at first, then a pilot-scale system was followed. Toluene was selected as a typical VOC for EB hybrid control to investigate by-products, effects of ceramic and catalyst, and factors affecting overall efficiency of degradation. It was concluded that VOCs could be destroyed more effectively by a novel hybrid system than single EB irradiation. (author)

Test of electron beam technology on Savannah River Laboratory low-activity aqueous waste for destruction of benzene, benzene derivatives, and bacteria

International Nuclear Information System (INIS)

Dougal, R.A.

1993-08-01

High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a 60 Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of 60 Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 μg/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those populations was also studied. 60 Co and electron beam irradiation were both lethal to the bacteria studied at irradiation levels far lower than were necessary to remove organic contaminants

A cohort study of intra-urban variations in volatile organic compounds and mortality, Toronto, Canada

International Nuclear Information System (INIS)

Villeneuve, Paul J.; Jerrett, Michael; Su, Jason; Burnett, Richard T.; Chen, Hong; Brook, Jeffrey; Wheeler, Amanda J.; Cakmak, Sabit; Goldberg, Mark S.

2013-01-01

This study investigated associations between long-term exposure to ambient volatile organic compounds (VOCs) and mortality. 58,760 Toronto residents (≥35 years of age) were selected from tax filings and followed from 1982 to 2004. Death information was extracted using record linkage to national mortality data. Land-use regression surfaces for benzene, n-hexane, and total hydrocarbons were generated from sampling campaigns in 2002 and 2004 and assigned to residential addresses in 1982. Cox regression was used to estimate relationships between each VOC and non-accidental, cardiovascular, and cancer mortality. Positive associations were observed for each VOC. In multi-pollutant models the benzene and total hydrocarbon signals were strongest for cancer. The hazard ratio for cancer that corresponded to an increase in the interquartile range of benzene (0.13 μg/m 3 ) was 1.06 (95% CI = 1.02–1.11). Our findings suggest ambient concentrations of VOCs were associated with cancer mortality, and that these exposures did not confound our previously reported associations between NO 2 and cardiovascular mortality. -- Highlights: ► We studied associations between long-term exposure to volatile organic compounds and mortality. ► The study was a population-based cohort of Toronto adults followed for up to 22 years. ► We used land-use regression estimates of benzene, total hydrocarbons and n-hexane. ► Benzene and total hydrocarbons were positively associated with cancer mortality. ► VOCs did not confound associations between NO 2 and cardiovascular mortality. -- Long-term exposure to ambient benzene was associated with non-accidental and cancer causes of death, and did not attenuate associations between NO 2 and cardiovascular mortality

Influence of adhesive bonding on quantity of emissions VOCs

Directory of Open Access Journals (Sweden)

Petr Čech

2008-01-01

Full Text Available The study deals with the influence of urea-formaldehyde glue and veneered bolstering on technological operation veneering on quantity of emission VOCs (volatile organic compounds.The so-called Volatile Organic Compounds (VOC are among the largest pollution sources of both the internal and external environments.VOC is defined as emission of any organic compound or a mixture thereof, with the exception of methane, whereby the compound exerts the pressure of 0.01 kPa or more at the temperature of 20 °C (293.15 K and reaches the corresponding volatility under the specific conditions of its use and can undergo photochemical reactions with nitrogen oxides when exposed to solar radiation.The effects of VOC upon environment can be described by equation:VOC + NOx + UV radiation + heat = tropospheric ozone (O3.In this work there were tested background working environment in various parts of multi-storeyed press, next was judged emissive charge of veneered device and used glue. We used surface material such as chipboard. We used urea-formaldehyde glue KRONOCOL U300 on technological operation veneering.The VOC emissions from the wooden surfaces with or without finishing were tested in the Equipment for VOC Measuring with a small-space chamber. This equipment was installed in and made available by the Institute of Furniture, Design and Habitation. The small-space chamber is suitable for testing small parts of wood products. The device equipped with small-chamber satisfies all conditions mandated in the standard ENV 13 419 DIN -V-ENV 13 419 ”Determination of the emissions of Volatile organic compounds”.The VOC emissions were collected in columns with sorbent Tenax TA. We analyzed the columns with the VOC emissions by: the gas chromatography in conjunction with mass spectrometer and Direct Thermal Desorption.

Assimilation and transformation of benzene by higher plants

Energy Technology Data Exchange (ETDEWEB)

Durmishidze, S V; Ugrekhelidze, D Sh; Dzhikiya, A N

1974-01-01

Higher plants are capable of assimilating benzene, the molecules of which are subjected to deep chemical transformations; the products of its metabolism move along the plant. Taking part in total metabolism, carbon atoms of benzene molecules incorporate into composition of low-molecular compounds of the plant cell. The bulk of benzene carbon incorporates into composition of organic acids and a comparatively small part - into composition of amino acids. In the metabolism process benzene carbon localizes mainly in the chloroplasts. Phenol, muconic acid and CO/sub 2/ are isolated and identified from the products of benzene enzymatic oxidation. A range of benzene assimilation by higher plants is extremely wide. 9 references, 5 tables.

An updated emission inventory of vehicular VOCs and IVOCs in China

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H. Liu

2017-10-01

Full Text Available Currently, the emission inventory of vehicular volatile organic compounds (VOCs is one of those with the largest errors and uncertainties due to suboptimal estimation methods and the lack of first-hand basic data. In this study, an updated speciated emission inventory of VOCs and an estimation of intermediate-volatility organic compounds (IVOCs from vehicles in China at the provincial level for the year of 2015 are developed based on a set of state-of-the-art methods and an abundance of local measurement data. Activity data for light-duty vehicles are derived from trajectories of more than 70 000 cars for 1 year. The annual mileage of trucks are calculated from reported data by more than 2 million trucks in China. The emission profiles are updated using measurement data. Vehicular tailpipe emissions (VTEs and four types of vehicular evaporation emissions (VEEs, including refueling, hot soak, diurnal and running loss, are taken into account. Results show that the total vehicular VOC emissions in China are 4.21 Tg (with a 95 % confidence interval range from 2.90 to 6.54 Tg and the IVOC emissions are 200.37 Gg in 2015. VTEs are still the predominant contributor, while VEEs are responsible for 39.20 % of VOC emissions. The control of VEEs is yet to be optimized in China. Among VTEs, passenger vehicles emissions have the largest share (49.86 %, followed by trucks (28.15 % and motorcycles (21.99 %. Among VEEs, running loss is the largest contributor (81.05 %. For both VTEs and VEEs, Guangdong, Shandong and Jiangsu province are three of the highest, with a respective contribution of 10.66, 8.85 and 6.54 % to the total amounts of VOCs from vehicles. 97 VOC species are analyzed in this VOC emission inventory. i-Pentane, toluene and formaldehyde are found to be the most abundant species in China's vehicular VOC emissions. The estimated IVOCs are another inconvenient truth, concluding that precursor emissions for secondary organic

Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

Science.gov (United States)

Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

2007-01-01

The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools.

Science.gov (United States)

Raysoni, Amit U; Stock, Thomas H; Sarnat, Jeremy A; Chavez, Mayra C; Sarnat, Stefanie Ebelt; Montoya, Teresa; Holguin, Fernando; Li, Wen-Whai

2017-12-01

A 14-week air quality study, characterizing the indoor and outdoor concentrations of 18 VOCs at four El Paso, Texas elementary schools, was conducted in Spring 2010. Three schools were in an area of high traffic density and the fourth school, considered as a background school, was situated in an area affected minimally by stationary and mobile sources of air pollution. Passive samplers were deployed for monitoring and analyzed by GC/MS. Differences in the concentration profiles of the BTEX species between the high and low traffic density schools confirmed the pre-defined exposure patterns. Toluene was the predominant compound within the BTEX group and the 96-hr average outdoor concentrations varied from 1.16 to 4.25 μg/m 3 across the four schools. Outdoor BTEX species were strongly correlated with each other (0.63 schools in contrast to the low-exposure school. This was further corroborated by the results obtained from the BTEX inter-species ratios (toluene: benzene and m, p- xylenes: ethylbenzene). Certain episodic events during the study period resulted in very elevated concentrations of some VOCs such as n-pentane. Indoor concentration of compounds with known indoor sources such as α -pinene, d-limonene, p-dichlorobenzene, and chloroform were generally higher than their corresponding outdoor concentrations. Cleaning agents, furniture polishes, materials used in arts and crafts activities, hot-water usage, and deodorizing cakes used in urinal pots were the likely major sources for these high indoor concentrations. Finally, retrospective assessment of average ambient BTEX concentrations over the last twenty years suggest a gradual decrement in this border region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Canadian soil quality guidelines for the protection of environmental and human health : benzene

Energy Technology Data Exchange (ETDEWEB)

Potter, K.

2005-07-01

This report presented soil quality guidelines for benzene to protect humans and ecological receptors in 4 types of land uses: agricultural; residential and parklands; commercial and industrial. The chemical and physical properties of benzene were reviewed, as well as the sources and emissions of benzene in Canada. The distribution and behaviour of benzene in the environment was examined, and the toxicological effects of benzene on microbial processes, plants, animals and humans were reviewed. It was noted that the background information and rationale for the derivation of Canadian Soil Quality Guidelines for this substance were originally published in 1999 by the Canadian Council of Ministers of the Environment (CCME) in Canadian Environmental Quality Guidelines. These guidelines have since been revised to reflect new data and lessons learned during the development of the Canada-wide Standard for Petroleum Hydrocarbons in Soil (CCME 2000). Modifications in this report included the derivation of guidelines for different soil textures and depths. Behaviour and effects in biota were reviewed, including soil microbial processes; terrestrial plants; terrestrial invertebrates; livestock and wildlife; and bioaccumulation. Behaviour and effects in humans and mammalian species were examined. The derivation of environmental soil quality guidelines was outlined. Recommendations for Canadian soil quality guidelines were presented. It was concluded that there is a lack of studies on the toxic effects of benzene on livestock, mammalian wildlife and birds and that studies on the metabolism of benzene in mammals and birds as well as invertebrates are needed. In addition, research is needed on the effects of benzene on nitrogen fixation, nitrification, nitrogen mineralization, decomposition and respiration. 118 refs., 3 tabs., 2 figs.

Benzene poisoning

Science.gov (United States)

... may be admitted to the hospital if the poisoning is severe. ... benzene they swallowed and how quickly they receive treatment. The ... Poisoning can cause rapid death. However, deaths have occurred ...

Analysis of Volatile Organic Compounds in the Ambient Air of a Paper Mill- A Case Study

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Xin Tong

2015-11-01

Full Text Available In this work, volatile organic compounds (VOCs in the ambient air of a secondary fiber paper mill were analyzed. For the sake of studying pollution comprehensively, four sites in the paper mill were analyzed and active sampling methods were used. Desorption was carried out with two solvents, carbon disulfide and dichloromethane. The compositions of VOCs were determined by gas chromatography-mass spectrometry (GC-MS method. The main identified substances in the four sites were as follows: (1 waste paper sorting room: alkanes, phenols, and esters; (2 papermaking workshop: benzene series, alkanes, ethers, and phenols; (3 vacuum pump outlet: benzene series and phenols; and (4 office area: benzene series and phenols. Two main toxic substances in VOCs, the benzene series and phenols, were detected in the ambient air of the paper mill. The benzene series existed in three places along the main process of the paper mill and even existed in the office area, which was far away from the production line. Additionally, phenols were detected in all sampling locations in the paper mill.

Antimalarial activity of compounds comprising a primary benzene sulfonamide fragment.

Science.gov (United States)

Andrews, Katherine T; Fisher, Gillian M; Sumanadasa, Subathdrage D M; Skinner-Adams, Tina; Moeker, Janina; Lopez, Marie; Poulsen, Sally-Ann

2013-11-15

Despite the urgent need for effective antimalarial drugs with novel modes of action no new chemical class of antimalarial drug has been approved for use since 1996. To address this, we have used a rational approach to investigate compounds comprising the primary benzene sulfonamide fragment as a potential new antimalarial chemotype. We report the in vitro activity against Plasmodium falciparum drug sensitive (3D7) and resistant (Dd2) parasites for a panel of fourteen primary benzene sulfonamide compounds. Our findings provide a platform to support the further evaluation of primary benzene sulfonamides as a new antimalarial chemotype, including the identification of the target of these compounds in the parasite. Copyright © 2013 Elsevier Ltd. All rights reserved.

Geogenic sources of benzene in aquifers used for public supply, California

Science.gov (United States)

Landon, Matthew K.; Belitz, Kenneth

2012-01-01

Statistical evaluation of two large statewide data sets from the California State Water Board's Groundwater Ambient Monitoring and Assessment Program (1973 wells) and the California Department of Public Health (12417 wells) reveals that benzene occurs infrequently (1.7%) and at generally low concentrations (median detected concentration of 0.024 μg/L) in groundwater used for public supply in California. When detected, benzene is more often related to geogenic (45% of detections) than anthropogenic sources (27% of detections). Similar relations are evident for the sum of 17 hydrocarbons analyzed. Benzene occurs most frequently and at the highest concentrations in old, brackish, and reducing groundwater; the detection frequency was 13.0% in groundwater with tritium 1600 μS/cm, and anoxic conditions. This groundwater is typically deep (>180 m). Benzene occurs somewhat less frequently in recent, shallow, and reducing groundwater; the detection frequency was 2.6% in groundwater with tritium ≥1 pCi/L, depth <30 m, and anoxic conditions. Evidence for geogenic sources of benzene include: higher concentrations and detection frequencies with increasing well depth, groundwater age, and proximity to oil and gas fields; and higher salinity and lower chloride/iodide ratios in old groundwater with detections of benzene, consistent with interactions with oil-field brines.

Experimental study and kinetic modeling of the thermal degradation of aromatic volatile organic compounds (benzene, toluene and xylene-para) in methane flames; Etude experimentale et modelisation cinetique de la degradation thermique des composes organiques volatils aromatiques benzenes, toluene et para-xylene dans des flammes de methane

Energy Technology Data Exchange (ETDEWEB)

Dupont, L.

2001-02-01

This study treats of the thermal degradation of a family of aromatic volatile organic compounds (VOCs) in laminar premixed methane flames at low pressure. The experimental influence of benzene, toluene and xylene-para on the structure of a reference methane flame has been studied. The molar fraction profiles of the stable and reactive, aliphatic, aromatic and cyclic species have been established by the coupling of the molecular beam sampling/mass spectroscopy technique with the gas chromatography/mass spectroscopy technique. Temperature profiles have been measured using a covered thermocouple. A detailed kinetic mechanism of oxidation of these compounds in flame conditions has been developed. Different available sub-mechanisms have been used as references: the GDF-Kin 1.0 model for the oxidation of methane and the models of Tan and Franck (1996) and of Lindstedt and Maurice (1996) in the case of benzene and toluene. In the case of para-xylene, a model has been developed because no mechanisms was available in the literature. These different mechanisms have been refined, completed or adjusted by comparing the experimental results with those obtained by kinetic modeling. The complete kinetic mechanism, comprising 156 chemical species involved in 1072 reactions allows to reproduce all the experimental observations in a satisfactory manner. The kinetic analysis of reactions velocity has permitted to determine oxidation kinetic schemes for benzene, toluene, xylene-para and for the cyclopentadienyl radical, main species at the origin of the rupture of the aromatic cycle. Reactions of recombination with the methyl radicals formed during methane oxidation, of the different aromatic or aliphatic radicals created during the oxidation of aromatics, play an important role and lead to the formation of several aromatic pollutants (ethyl-benzene for instance) or aliphatic pollutants (butadiene or penta-diene for instance) in flames. (J.S.)

FORMULATING ULTRA-LOW-VOC WOOD FURNITURE COATINGS

Science.gov (United States)

The article discusses the formulation of ultra-low volatile organic compound (VOC) wood furniture coatings. The annual U.S. market for wood coatings is about 240, 000 cu m (63 million gal). In this basis, between 57 and 91 million kg (125 and 200 million lb) of VOCs are emitted i...

Characteristics of Ambient Volatile Organic Compounds (VOCs Measured in Shanghai, China

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Guang-Qiang Zhou

2010-08-01

Full Text Available To better understand the characteristics of ambient abundance of volatile organic compounds (VOCs in Shanghai, one of the biggest metropolis of China, VOCs were measured with a gas chromatography system equipped with a mass-selective detector (GC/MSD from July 2006 to February 2010. An intensive measurement campaign was conducted (eight samples per day with a 3 hour interval during May 2009. The comparison of ambient VOCs collected in different regions of Shanghai shows that the concentrations are slightly higher in the busy commercial area (28.9 ppbv at Xujiaui than in the urban administrative area (24.3 ppbv at Pudong. However, during the intensive measurement period, the concentrations in the large steel industrial area (28.7 ppbv at Baoshan were much higher than in the urban administrative area (18 ppbv at Pudong, especially for alkanes, alkenes, and toluene. The seasonal variations of ambient VOC concentrations measured at the Xujiahui sampling site indicate that the VOC concentrations are significantly affected by meteorological conditions (such as wind direction and precipitation. In addition, although alkanes are the most abundant VOCs at the Xujiahui measurement site, the most important VOCs contributing to ozone formation potential (OFP are aromatics, accounting for 57% of the total OFP. The diurnal variations of VOC concentrations show that VOC concentrations are higher on weekdays than in weekends at the Xujiahui sampling site, suggesting that traffic condition and human activities have important impacts on VOC emissions in Shanghai. The evidence also shows that the major sources of isoprene are mainly resulted from gasoline evaporation at a particular time (06:00–09:00 in the busy commercial area. The results gained from this study provide useful information for better understanding the characteristics of ambient VOCs and the sources of VOCs in Shanghai.

Characteristics of Ambient Volatile Organic Compounds (VOCs) Measured in Shanghai, China

Science.gov (United States)

Cai, Chang-Jie; Geng, Fu-Hai; Tie, Xue-Xi; Yu, Qiong; Peng, Li; Zhou, Guang-Qiang

2010-01-01

To better understand the characteristics of ambient abundance of volatile organic compounds (VOCs) in Shanghai, one of the biggest metropolis of China, VOCs were measured with a gas chromatography system equipped with a mass-selective detector (GC/MSD) from July 2006 to February 2010. An intensive measurement campaign was conducted (eight samples per day with a 3 hour interval) during May 2009. The comparison of ambient VOCs collected in different regions of Shanghai shows that the concentrations are slightly higher in the busy commercial area (28.9 ppbv at Xujiaui) than in the urban administrative area (24.3 ppbv at Pudong). However, during the intensive measurement period, the concentrations in the large steel industrial area (28.7 ppbv at Baoshan) were much higher than in the urban administrative area (18 ppbv at Pudong), especially for alkanes, alkenes, and toluene. The seasonal variations of ambient VOC concentrations measured at the Xujiahui sampling site indicate that the VOC concentrations are significantly affected by meteorological conditions (such as wind direction and precipitation). In addition, although alkanes are the most abundant VOCs at the Xujiahui measurement site, the most important VOCs contributing to ozone formation potential (OFP) are aromatics, accounting for 57% of the total OFP. The diurnal variations of VOC concentrations show that VOC concentrations are higher on weekdays than in weekends at the Xujiahui sampling site, suggesting that traffic condition and human activities have important impacts on VOC emissions in Shanghai. The evidence also shows that the major sources of isoprene are mainly resulted from gasoline evaporation at a particular time (06:00–09:00) in the busy commercial area. The results gained from this study provide useful information for better understanding the characteristics of ambient VOCs and the sources of VOCs in Shanghai. PMID:22163629

Benzene adsorption and oxidation on Ir(111)

NARCIS (Netherlands)

Weststrate, C.J.; Bakker, J.W.; Gluhoi, A.C.; Ludwig, W.; Nieuwenhuys, B.E.

2007-01-01

Adsorption, decompn. and oxidn. of benzene on Ir(1 1 1) was studied by high resoln. (synchrotron) XPS, temp. programmed desorption and LEED. Mol. adsorption of benzene on Ir(1 1 1) is obsd. between 170 K and 350 K. Above this temp. both desorption and decompn. of benzene take place. An ordered

Survey of benzene and aromatics in Canadian Gasoline - 1994

International Nuclear Information System (INIS)

Tushingham, M.

1996-01-01

A comprehensive database of the benzene and aromatics levels of gasoline produced in or imported into Canada during 1994, was presented. Environment Canada conducted a survey that requested refineries and importers to report quarterly on benzene and aromatics levels in gasoline. Benzene, which has been declared toxic by the Canadian Environmental Protection Act, is found in gasoline and is formed during the combustion of the aromatic components of gasoline. It was shown that benzene and aromatics levels differ regionally and seasonally. There are also variations in benzene levels between batches of gasoline produced at any one refinery. This report listed the responses to the benzene/aromatics survey. It also described the analytical procedures used to measure benzene and aromatics levels in gasoline, and provided guidelines for reporting gasoline benzene and total aromatics data. 7 tabs., 21 figs

[Study on of the current status of volatile organic compounds pollution in typical rural drinking water and the relationship between its concentration and health of the population, in Huai'an, Jiangsu].

Science.gov (United States)

Pan, Enchun; Zhang, Qin; Yang, Fangying; Hu, Wei; Xu, Qiujin; Liang, Cunzhen; He, Yuan; Wang, Chuang

2014-10-01

This study was to understand the status of pollution on drinking water, by volatile organic compounds (VOCs), among rural residents living in the basin of Huaihe River. Relationship between the morbidity, morbidity of cancers and VOCs were also explored. 28 villages were chosen from Xuyi,Jinhu, Chuzhou along the Huaihe River, with water samples collected from ditch pond water, shallow wells, deep wells in November-December 2010. VOCs indicators were evaluated according to the Standard Quality GB 5749-2006 for Drinking Water. Methylene chloride, chloroform, benzene and carbon tetrachloride were all detected in 76 water samples. The rates of chloroform, benzene, carbon tetrachloride which exceeding the quality standards were 3.95% , 21.05% and 22.37% , but no significant differences were found among these three water resources in chloroform, benzene or carbon tetrachloride. Results from the correlation analysis showed that benzene had positive correlation with tumor deaths (r = 0.24, P water resources (P > 0.05). Drinking waters for rural residents along the Huaihe River were polluted while VOCs might have related to tumor incidence with potential impact and risk to the health of local residents.

Locating industrial VOC sources with aircraft observations

International Nuclear Information System (INIS)

Toscano, P.; Gioli, B.; Dugheri, S.; Salvini, A.; Matese, A.; Bonacchi, A.; Zaldei, A.; Cupelli, V.; Miglietta, F.

2011-01-01

Observation and characterization of environmental pollution, focussing on Volatile Organic Compounds (VOCs), in a high-risk industrial area, are particularly important in order to provide indications on a safe level of exposure, indicate eventual priorities and advise on policy interventions. The aim of this study is to use the Solid Phase Micro Extraction (SPME) method to measure VOCs, directly coupled with atmospheric measurements taken on a small aircraft environmental platform, to evaluate and locate the presence of VOC emission sources in the Marghera industrial area. Lab analysis of collected SPME fibres and subsequent analysis of mass spectrum and chromatograms in Scan Mode allowed the detection of a wide range of VOCs. The combination of this information during the monitoring campaign allowed a model (Gaussian Plume) to be implemented that estimates the localization of emission sources on the ground. - Highlights: → Flight plan aimed at sampling industrial area at various altitudes and locations. → SPME sampling strategy was based on plume detection by means of CO 2 . → Concentrations obtained were lower than the limit values or below the detection limit. → Scan mode highlighted presence of γ-butyrolactone (GBL) compound. → Gaussian dispersion modelling was used to estimate GBL source location and strength. - An integrated strategy based on atmospheric aircraft observations and dispersion modelling was developed, aimed at estimating spatial location and strength of VOC point source emissions in industrial areas.

Muonium radicals in benzene-styrene mixtures

International Nuclear Information System (INIS)

Ng, B.W.; Stadlbauer, J.W.; Walker, D.C.

1984-01-01

Muonium radicals were observed through their μ + SR precession frequencies in high transverse magnetic fields in pure benzene, pure styrene and their mixtures, all as liquids at room temperature. In benzene-styrene mixtures, the radicals obtained in each pure liquid are both present, so no slow (10 -9 -10 -5 s) intermolecular exchange occurs; but strong selectivity was found with the formation of the radical from styrene being about eight-times more probable than the radical from benzene. (Auth.)

VOCs and odors: key factors in selecting `green` building materials?

Energy Technology Data Exchange (ETDEWEB)

Coombs, C. [Steven Winter Associates Inc., Norwalk, CT and Washington DC (United States)

1998-12-01

The current state of knowledge available for selecting building materials on the basis of emissions of volatile organic compounds (VOCs) and odors is reviewed. The significance of VOCs and odors in building materials is related to their role in influencing indoor air quality. As far as toxicity is concerned, many of the VOCs detected in indoor air are relatively inert when considered singly. They are not however, unimportant because in actual fact they are invariably found in mixtures some of which can be toxic. Although knowledge of VOCs is incomplete, it is important to specify ozone-resistant polymeric building products, i.e. those that are chemically stable and inert to oxidation. In addition to VOCs, attention should also be focused on semi-volatile organic compounds (SVOCs) since they are even more persistent than VOCs and tend to offgas for prolonged periods of time. Similarly, it is reasonable to specify low-odor materials. Inclusion of issues related to complex indoor chemistry, less volatile emissions, in addition to VOCs and odor, should in time result in expanded choices of building materials that promote indoor air quality. 16 refs.,2 tabs.

Influence of way of finishing furniture segments on amount emissions VOCs

Directory of Open Access Journals (Sweden)

Petr Čech

2010-01-01

Full Text Available The study deals with the influence of way of finishing furniture segments on amount emissions VOCs (volatile organic compounds. The so-called Volatile Organic Compounds (VOC are among the largest pollution sources of both the internal and external environments.VOC is defined as emission of any organic compound or a mixture thereof, with the exception of methane, whereby the compound exerts the pressure of 0.01 kPa or more at the temperature of 20 °C (293.15 K and reaches the corresponding volatility under the specific conditions of its use and can undergo photochemical reactions with nitrogen oxides when exposed to solar radiation. The effects of VOC upon environment can be described by equation: VOC + NOx + UV radiation + heat = tropospheric ozone (O3In this work there were tested MDF (medium density fibreboard coated by resin impregnated paper was used for the furniture components’ production. Next were tested compressed wood, which was used as a second material of furniture components. These both chosen materials was covered by resin impregnated paper and than sequentially finished by regular coat of finish.An attention of this study is especially put on mentioned factors and on quantity of instant and long-term VOCs emissions emitted from furniture components.The amount of emissions from furniture components, in different phases of the preparation including the resin impregnated paper coating finish, was monitored within the time intervals of 24 hours and 720 hours starting after the time of the finish preparation.The MDF (medium density fibreboard coated by resin impregnated paper was used for the furniture components´ production.A compressed wood was used as a second material of furniture components. This alternative material was covered by resin impregnated paper and than sequentially finished by regular coat of finish.

Fighting against VOC emissions; Lutter contre les emissions de COV

Energy Technology Data Exchange (ETDEWEB)

Fanlo, J.L. [Ecole des Mines d' Ales, 30 (France); Puech, G. [APAVE, 75 - Paris (France); Patoux, R. [Rhodia Rhoditech (France)] [and others

2001-12-01

This document brings together 15 testimonies of experts about the processes used in the industry for the abatement of volatile organic compound (VOC) emissions. The different points approached concern: the first industrial experiments of fight against VOC emissions, how to audit the facilities, how to make a diagnosis, to hierarchized and to measure continuously VOC emissions, how to anticipate the explosion risks linked with VOC treatment processes, the techniques of VOC abatement at the source implemented by industrialists, the implementation of an emission mastery scheme by Crow Cork and Seal company, the implementation of a solvent management plan by Turbomeca company and of a paints strategy by Renault car-making company, the combination of VOC abatement techniques implemented by industrialists, the classification of destruction and recovery processes: the experience feedback of Sanofi Synthelabo and of Air Liquide companies, the combination of upstream and downstream techniques implemented by Pechiney Rhenalu, Ashland Polyester and Quebecor companies. (J.S.)

Volatile Organic Compounds (VOCs in Conventional and High Performance School Buildings in the U.S.

Directory of Open Access Journals (Sweden)

Lexuan Zhong

2017-01-01

Full Text Available Exposure to volatile organic compounds (VOCs has been an indoor environmental quality (IEQ concern in schools and other buildings for many years. Newer designs, construction practices and building materials for “green” buildings and the use of “environmentally friendly” products have the promise of lowering chemical exposure. This study examines VOCs and IEQ parameters in 144 classrooms in 37 conventional and high performance elementary schools in the U.S. with the objectives of providing a comprehensive analysis and updating the literature. Tested schools were built or renovated in the past 15 years, and included comparable numbers of conventional, Energy Star, and Leadership in Energy and Environmental Design (LEED-certified buildings. Indoor and outdoor VOC samples were collected and analyzed by thermal desorption, gas chromatography and mass spectroscopy for 94 compounds. Aromatics, alkanes and terpenes were the major compound groups detected. Most VOCs had mean concentrations below 5 µg/m3, and most indoor/outdoor concentration ratios ranged from one to 10. For 16 VOCs, the within-school variance of concentrations exceeded that between schools and, overall, no major differences in VOC concentrations were found between conventional and high performance buildings. While VOC concentrations have declined from levels measured in earlier decades, opportunities remain to improve indoor air quality (IAQ by limiting emissions from building-related sources and by increasing ventilation rates.

Volatile Organic Compounds (VOCs) in Conventional and High Performance School Buildings in the U.S.

Science.gov (United States)

Zhong, Lexuan; Su, Feng-Chiao; Batterman, Stuart

2017-01-21

Exposure to volatile organic compounds (VOCs) has been an indoor environmental quality (IEQ) concern in schools and other buildings for many years. Newer designs, construction practices and building materials for "green" buildings and the use of "environmentally friendly" products have the promise of lowering chemical exposure. This study examines VOCs and IEQ parameters in 144 classrooms in 37 conventional and high performance elementary schools in the U.S. with the objectives of providing a comprehensive analysis and updating the literature. Tested schools were built or renovated in the past 15 years, and included comparable numbers of conventional, Energy Star, and Leadership in Energy and Environmental Design (LEED)-certified buildings. Indoor and outdoor VOC samples were collected and analyzed by thermal desorption, gas chromatography and mass spectroscopy for 94 compounds. Aromatics, alkanes and terpenes were the major compound groups detected. Most VOCs had mean concentrations below 5 µg/m³, and most indoor/outdoor concentration ratios ranged from one to 10. For 16 VOCs, the within-school variance of concentrations exceeded that between schools and, overall, no major differences in VOC concentrations were found between conventional and high performance buildings. While VOC concentrations have declined from levels measured in earlier decades, opportunities remain to improve indoor air quality (IAQ) by limiting emissions from building-related sources and by increasing ventilation rates.

UV and condensation technology for applications in the UOG for removal of air contaminants

Energy Technology Data Exchange (ETDEWEB)

De Visscher, A.; Langford, C.H. [Calgary Univ., AB (Canada)

2008-07-01

Canadian emissions of volatile organic compounds (VOC) are significant. In 2006, the upstream oil and gas (UOG) industry in Canada emitted over 500,000 tonnes of volatile organic compounds per year. 2002 benzene emissions from glycol dehydration units in Canada were estimated at 1,988 tonnes. These emissions are from a large number of sources typically emitting a few tonnes per year. Although condensation systems can reduce emissions, they leave residual emissions. New technologies to reduce emissions would have to be fairly inexpensive and simple given the large number of sources. This presentation addressed two research questions, notably how to predict condensation unit efficiency; and the feasibility of photolysis in UOG waste gas treatment, including glycol dehydration emissions. The presentation discussed the objectives of the study, which were to develop capability to predict efficiencies of condensation units; to develop proof-of-concept of effective ultraviolet technology for treating benzene and other VOCs from upstream oil and gas; and to test the technique for hydrogen sulphide. The presentation discussed the prediction of benzene condensation including the problem, hypothesis, and proposed approach. An introduction to photolysis was also provided. Some chemical reactions of benzene photolysis were demonstrated. Several illustrations were used to show a benzene photolysis reactor; a photocatalytic alternative; and a radiation field simulation model. It was concluded that a predictive model for efficiency of condensation for benzene emission reduction from glycol dehydration units will be developed accounting for non-steady behaviour. 4 figs.

Volatile organic compound (VOC) emissions during malting and beer manufacture

Science.gov (United States)

Gibson, Nigel B.; Costigan, Gavin T.; Swannell, Richard P. J.; Woodfield, Michael J.

Estimates have been made of the amounts of volatile organic compounds (VOCs) released during different stages of beer manufacture. The estimates are based on recent measurements and plant specification data supplied by manufacturers. Data were obtained for three main manufacturing processes (malting, wort processing and fermentation) for three commercial beer types. Some data on the speciation of emitted compounds have been obtained. Based on these measurements, an estimate of the total unabated VOC emission. from the U.K. brewing industry was calculated as 3.5 kta -1, over 95% of which was generated during barley malting. This value does not include any correction for air pollution control.

An Admiralty for Asia: Isaac le Maire and conflicting conceptions about the corporate governance of the VOC

NARCIS (Netherlands)

O. Gelderblom (Oscar); A. de Jong (Abe); J. Jonker (Joost)

2010-01-01

textabstractThe Dutch East India Company or VOC in 1602 showed many characteristics of modern corporations, including limited liability, freely transferable shares, and well-defined managerial functions. However, we challenge the notion of the VOC as the precursor of modern corporations to argue

Eddy covariance VOC emission and deposition fluxes above grassland using PTR-TOF

Directory of Open Access Journals (Sweden)

T. M. Ruuskanen

2011-01-01

Full Text Available Eddy covariance (EC is the preferable technique for flux measurements since it is the only direct flux determination method. It requires a continuum of high time resolution measurements (e.g. 5–20 Hz. For volatile organic compounds (VOC soft ionization via proton transfer reaction has proven to be a quantitative method for real time mass spectrometry; here we use a proton transfer reaction time of flight mass spectrometer (PTR-TOF for 10 Hz EC measurements of full mass spectra up to m/z 315. The mass resolution of the PTR-TOF enabled the identification of chemical formulas and separation of oxygenated and hydrocarbon species exhibiting the same nominal mass. We determined 481 ion mass peaks from ambient air concentration above a managed, temperate mountain grassland in Neustift, Stubai Valley, Austria. During harvesting we found significant fluxes of 18 compounds distributed over 43 ions, including protonated parent compounds, as well as their isotopes and fragments and VOC-H⁺ – water clusters. The dominant BVOC fluxes were methanol, acetaldehyde, ethanol, hexenal and other C₆ leaf wound compounds, acetone, acetic acid, monoterpenes and sequiterpenes.

The smallest reliable fluxes we determined were less than 0.1 nmol m⁻² s⁻¹, as in the case of sesquiterpene emissions from freshly cut grass. Terpenoids, including mono- and sesquiterpenes, were also deposited to the grassland before and after the harvesting. During cutting, total VOC emission fluxes up to 200 nmolC m⁻² s⁻¹ were measured. Methanol emissions accounted for half of the emissions of oxygenated VOCs and a third of the carbon of all measured VOC emissions during harvesting.

[Evaluation and selection of VOCs treatment technologies in packaging and printing industry].

Science.gov (United States)

Wang, Hai-Lin; Wang, Jun-Hui; Zhu, Chun-Lei; Nie, Lei; Hao, Zheng-Ping

2014-07-01

Volatile organic compounds (VOCs) play an important role in urban air pollution. Activities of industries including the packaging and printing industries are regarded as the major sources. How to select the suitable treating techniques is the major problem for emission control. In this article, based on the VOCs emission characteristics of the packaging and printing industry and the existing treatment technologies, using the analytic hierarchy process (AHP) model, an evaluation system for VOCs selection was established and all the technologies used for treatment were assessed. It showed that the priority selection was in the following order: Carbon Fiber Adsorption-Desorption > Granular Carbon Adsorption-Desorption > Thermal Combustion > Regenerative Combustion > Catalytic combustion > Rotary adsorption-concentration and combustion > Granular Carbon adsorption-concentration and combustion. Carbon Fiber Adsorption-Desorption was selected as the best available technology due to its highest weight among those technologies.

Reducing VOC Press Emission from OSB Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Dr. Gary D. McGinnis; Laura S. WIlliams; Amy E. Monte; Jagdish Rughani: Brett A. Niemi; Thomas M. Flicker

2001-12-31

Current regulations require industry to meet air emission standards with regard to particulates, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and other gases. One of many industries that will be affected by the new regulations is the wood composites industry. This industry generates VOCs, HAPs, and particulates mainly during the drying and pressing of wood. Current air treatment technologies for the industry are expensive to install and operate. As regulations become more stringent, treatment technologies will need to become more efficient and cost effective. The overall objective of this study is to evaluate the use of process conditions and chemical additives to reduce VOC/HAPs in air emitted from presses and dryers during the production of oriented strand board.

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong I. [Division of R and D Planning and Management, Korea Institute of Environmental Science and Technology, Seoul (Korea, Republic of); Nam, Kyongphile [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Park, Jae W. [Department of Civil Engineering, Hanyang University, Seoul (Korea, Republic of); Khim, Jee H. [Department of Civil and Environmental Engineering, Korea University, Seoul (Korea, Republic of); Kim, Yong K. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Kim, Jae Y. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of)], E-mail: jaeykim@snu.ac.kr

2008-05-01

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs.

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

International Nuclear Information System (INIS)

Oh, Dong I.; Nam, Kyongphile; Park, Jae W.; Khim, Jee H.; Kim, Yong K.; Kim, Jae Y.

2008-01-01

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs

Indicators of benzene emissions and exposure in Bangkok street

International Nuclear Information System (INIS)

Leong, S.T.; Laortanakul, Preecha

2003-01-01

Ambient benzene measurements were conducted for the first time at four air monitoring sites in the Bangkok metropolitan region (BMR), from January to December 2001. Analytical results show that the mean benzene concentrations range from 42.4 μg/m 3 at the Din Daeng urban site to 15.1 μg/m 3 at the Chaeng Wattana suburban site. The monitoring results show that at a larger distance from the roadside or a higher level from the street surface, the level of benzene decreases. Analysis of the ambient benzene concentrations was carried out with reference to meteorological influences and traffic density. In traffic analysis, the combined effects of street topography and traffic flows established high impact on the overall benzene concentration in Bangkok. Statistical analysis shows good correlations of blood benzene levels and trans, trans-muconic acid with ambient benzene and demonstrated substantial exposure from traffic

Application of ion chemistry to tropospheric VOC measurements

International Nuclear Information System (INIS)

Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

2002-01-01

The main interest in tropospheric volatile organic compounds (VOCs) originating from biogenic sources such as forests and anthropogenic sources such as cities is because these reactive trace gases can have a significant impact on levels of oxidants such as ozone (O 3 ) and the hydroxyl radical (OH). The proton-transfer-reaction mass-spectrometry (PTR-MS) technique developed by Werner Lindingers Laboratory, utilizes positive ion chemistry to measure trace neutral concentrations in air. It has been applied in food research, medicine and environmental studies to gain gas phase information about VOCs at parts per trillion (pptv) levels.The real-time method relies on proton transfer reactions between H 3 O + primary ions and VOCs which have a higher proton affinity than water molecules. Organic trace gases such as hydrocarbons, carbonyls, alcohols, acetonitrile, and others can be monitored on-line.Results on tropospheric VOCs measurements in tropical regions and in cities are discussed. (nevyjel)

Benzene exposure is associated with cardiovascular disease risk.

Directory of Open Access Journals (Sweden)

Wesley Abplanalp

Full Text Available Benzene is a ubiquitous, volatile pollutant present at high concentrations in toxins (e.g. tobacco smoke known to increase cardiovascular disease (CVD risk. Despite its prevalence, the cardiovascular effects of benzene have rarely been studied. Hence, we examined whether exposure to benzene is associated with increased CVD risk. The effects of benzene exposure in mice were assessed by direct inhalation, while the effects of benzene exposure in humans was assessed in 210 individuals with mild to high CVD risk by measuring urinary levels of the benzene metabolite trans,trans-muconic acid (t,t-MA. Generalized linear models were used to assess the association between benzene exposure and CVD risk. Mice inhaling volatile benzene had significantly reduced levels of circulating angiogenic cells (Flk-1+/Sca-1+ as well as an increased levels of plasma low-density lipoprotein (LDL compared with control mice breathing filtered air. In the human cohort, urinary levels of t,t-MA were inversely associated several populations of circulating angiogenic cells (CD31+/34+/45+, CD31+/34+/45+/AC133-, CD34+/45+/AC133+. Although t,t-MA was not associated with plasma markers of inflammation or thrombosis, t,t-MA levels were higher in smokers and in individuals with dyslipidemia. In smokers, t,t-MA levels were positively associated with urinary metabolites of nicotine (cotinine and acrolein (3-hydroxymercapturic acid. Levels of t,t-MA were also associated with CVD risk as assessed using the Framingham Risk Score and this association was independent of smoking. Thus, benzene exposure is associated with increased CVD risk and deficits in circulating angiogenic cells in both smokers and non-smokers.

The contribution of benzene to smoking-induced leukemia.

Science.gov (United States)

Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

2000-04-01

Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts to estimate the leukemogenic potency of benzene. Using multiple-decrement life tables, we calculated lifetime risks of total leukemia and AML deaths for never, light, and heavy smokers. We repeated these calculations, removing the effect of benzene in cigarettes based on the estimated potencies. From these life tables we determined smoking-attributable risks and benzene-attributable risks. The ratio of the latter to the former constitutes the proportion of smoking-induced cases attributable to benzene. Based on linear potency models, the benzene in cigarette smoke contributed from 8 to 48% of smoking-induced total leukemia deaths [95% upper confidence limit (UCL), 20-66%], and from 12 to 58% of smoking-induced AML deaths (95% UCL, 19-121%). The inclusion of a quadratic term yielded results that were comparable; however, potency models with only quadratic terms resulted in much lower attributable fractions--all models substantially overestimate low-dose risk, linear extrapolations from empirical data over a dose range of 10- to 100-fold resulted in plausible predictions.

Benzene monitoring at CPPI service stations

International Nuclear Information System (INIS)

Davis, C.S.

1996-01-01

A study was conducted in which ambient airborne concentration levels of benzene were measured at a representative set of gasoline service stations in Toronto and Vancouver. Benzene is considered to be toxic under the Canadian Environmental Protection Act (CEPA). It is a component in gasoline (0.1 to 4.7 per cent by volume) and is present in vehicle evaporative and exhaust emissions. Measurements were made every 18 days at each station for one year. The objective of the study was to assess the ambient and employee exposure levels of benzene at service stations and to determine whether the levels were typical of those published in the literature. In a 1986 PACE (Petroleum Association for Conservation of the Canadian Environment) survey of exposure to gasoline hydrocarbon vapours at Canadian service stations, airborne benzene concentration data was inconsistent with similar ambient and personal exposure data in the international literature. It was concluded that both the mean ambient benzene concentration and the personal exposure level measurements in this study were generally lower than similar measurements made in other countries. The same observation was made with respect to ambient and personal exposure levels measured in this study vis-a-vis those measured during the PACE study conducted in 1985/86. . 31 refs., 24 tabs., 5 figs

An overview of published benzene exposure data by industry in China, 1960-2003.

Science.gov (United States)

Liang, You-Xin; Wong, Otto; Armstrong, Thomas; Ye, Xi-Biao; Miao, Li-Zhuang; Zhou, Yi-Mei; Wu, Qiang-En; Qian, Hao-Jun; Fu, Hua

2005-05-30

This article presents an overview of occupational benzene exposures in China based on data published in Chinese medical journals. The data were derived from 384 reports of benzene poisoning or industrial hygiene surveys published in Chinese medical journals between 1960 and 2003. The following information was extracted whenever available: industry, occupation, task, date, benzene levels, sampling location, workplace descriptions and, for case reports, medical diagnosis. Each paper provided one or more sets of benzene data, each set representing a sampling location or job title with one to several measurements including, mainly, breathing zone area concentration measurements, and much less frequently personal monitoring. Two criteria based on data quality were applied to select suitable data for analyses. The selected exposure data were analyzed by industry and time period. Nine hundred five sets of benzene measurements from 72 industries were reported in the 384 papers selected for this review, and 621 sets (68.6%) presented average benzene concentrations, which covered 55 industries. The distribution of the reported average benzene exposures was skewed with a median of 51.5 mg/m3. The average benzene concentrations were below 100 mg/m3 for 406 (65%) of the 621 reported average concentrations. The medians of the reported averages in mg/m3 for the five industries with the highest exposures were: 124.8 for leather products, 98.7 for electronic devices, 75.4 for machinery, 50.4 for shoes, and 50.3 for office supplies and sports equipment manufacturing. These data describe the concentrations and changing patterns of occupational benzene exposure by industry and time period in China.

Evaporative Gasoline Emissions and Asthma Symptoms

Science.gov (United States)

Gordian, Mary Ellen; Stewart, Alistair W; Morris, Stephen S

2010-01-01

Attached garages are known to be associated with indoor air volatile organic compounds (VOCs). This study looked at indoor exposure to VOCs presumably from evaporative emissions of gasoline. Alaskan gasoline contains 5% benzene making benzene a marker for gasoline exposure. A survey of randomly chosen houses with attached garages was done in Anchorage Alaska to determine the exposure and assess respiratory health. Householders were asked to complete a health survey for each person and a household survey. They monitored indoor air in their primary living space for benzene, toluene, ethylbenzene and xylenes for one week using passive organic vapor monitoring badges. Benzene levels in homes ranged from undetectable to 58 parts per billion. The median benzene level in 509 homes tested was 2.96 ppb. Elevated benzene levels in the home were strongly associated with small engines and gasoline stored in the garage. High concentrations of benzene in gasoline increase indoor air levels of benzene in residences with attached garages exposing people to benzene at levels above ATSDR’s minimal risk level. Residents reported more severe symptoms of asthma in the homes with high gasoline exposure (16%) where benzene levels exceeded the 9 ppb. PMID:20948946

Radiocarbon dating methods using benzene liquid scintillation

International Nuclear Information System (INIS)

Togashi, Shigeko; Matsumoto, Eiji

1983-01-01

The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

The safety of non-incineration waste disposal devices in four hospitals of Tehran.

Science.gov (United States)

Farshad, Aliasghar; Gholami, Hamid; Farzadkia, Mahdi; Mirkazemi, Roksana; Kermani, Majid

2014-01-01

The safe management of hospital waste is a challenge in many developing countries. The aim of this study was to compare volatile organic compounds (VOCs) emissions and the microbial disinfectant safety in non-incineration waste disposal devices. VOC emissions and microbial infections were measured in four non-incineration waste disposal devices including: autoclave with and without a shredder, dry heat system, and hydroclave. Using NIOSH and US EPA-TO14 guidelines, the concentration and potential risk of VOCs in emitted gases from four devices were assessed. ProSpore2 biological indicators were used to assess the microbial analysis of waste residue. There was a significant difference in the type and concentration of VOCs and microbial infection of residues in the four devices. Emissions from the autoclave with a shredder had the highest concentration of benzene, ethyl benzene, xylene, and BTEX, and emissions from the hydroclave had the highest concentration of toluene. The highest level of microbial infection was observed in the residues of the autoclave without a shredder. There is an increased need for proper regulation and control of non-incinerator devices and for monitoring and proper handling of these devices in developing countries.

Volatile Organic Compound (VOC) measurements in the Pearl River Delta (PRD) region, China

Science.gov (United States)

Liu, Ying; Shao, Min; Lu, Sihua; Chang, Chih-Chung; Wang, Jia-Lin; Chen, Gao

2008-03-01

We measured levels of ambient volatile organic compounds (VOCs) at seven sites in the Pearl River Delta (PRD) region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ) and Xinken (XK), were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40%) in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%). Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles); those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

Volatile Organic Compound (VOC measurements in the Pearl River Delta (PRD region, China

Directory of Open Access Journals (Sweden)

Chih-chung Chang

2008-03-01

Full Text Available We measured levels of ambient volatile organic compounds (VOCs at seven sites in the Pearl River Delta (PRD region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ and Xinken (XK, were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40% in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%. Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles; those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

Ionic liquid technology to recover volatile organic compounds (VOCs).

Science.gov (United States)

Salar-García, M J; Ortiz-Martínez, V M; Hernández-Fernández, F J; de Los Ríos, A P; Quesada-Medina, J

2017-01-05

Volatile organic compounds (VOCs) comprise a wide variety of carbon-based materials which are volatile at relatively low temperatures. Most of VOCs pose a hazard to both human health and the environment. For this reason, in the last years, big efforts have been made to develop efficient techniques for the recovery of VOCs produced from industry. The use of ionic liquids (ILs) is among the most promising separation technologies in this field. This article offers a critical overview on the use of ionic liquids for the separation of VOCs both in bulk and in immobilized form. It covers the most relevant works within this field and provides a global outlook on the limitations and future prospects of this technology. The extraction processes of VOCs by using different IL-based assemblies are described in detail and compared with conventional methods This review also underlines the advantages and limitations posed by ionic liquids according to the nature of the cation and the anions present in their structure and the stability of the membrane configurations in which ILs are used as liquid phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and analysis of zero gases for the measurement of trace VOCs in air monitoring

Science.gov (United States)

Englert, Jennifer; Claude, Anja; Demichelis, Alessia; Persijn, Stefan; Baldan, Annarita; Li, Jianrong; Plass-Duelmer, Christian; Michl, Katja; Tensing, Erasmus; Wortman, Rina; Ghorafi, Yousra; Lecuna, Maricarmen; Sassi, Guido; Sassi, Maria Paola; Kubistin, Dagmar

2018-06-01

Air quality observations are performed globally to monitor the status of the atmosphere and its level of pollution and to assess mitigation strategies. Regulations of air quality monitoring programmes in various countries demand high-precision measurements for harmful substances often at low trace concentrations. These requirements can only be achieved by using high-quality calibration gases including high-purity zero gas. For volatile organic compound (VOC) observations, zero gas is defined as being hydrocarbon-free and can be, for example, purified air, nitrogen or helium. It is essential for the characterisation of the measurement devices and procedures, for instrument operation as well as for calibrations. Two commercial and one self-built gas purifiers were tested for their VOC removal efficiency following a standardised procedure. The tested gas purifiers included one adsorption cartridge with an inorganic media and two types of metal catalysts. A large range of VOCs were investigated, including the most abundant species typically measured at air monitoring stations. Both catalysts were able to remove a large range of VOCs whilst the tested adsorption cartridge was not suitable to remove light compounds up to C4. Memory effects occurred for the adsorption cartridge when exposed to higher concentration. This study emphasises the importance of explicitly examining a gas purifier for its intended application before applying it in the field.

Sulfur tolerance of Pt/mordenites for benzene hydrogenation. Do Bronsted acid sites participate in hydrogenation?

NARCIS (Netherlands)

Simon, L.; van Ommen, J.G.; Jentys, A.; Lercher, J.A.

2002-01-01

The comparison of Pt electronic properties studied by in situ XANES and the kinetic study of benzene hydrogenation strongly suggests that the hydrogenation of benzene on Pt/mordenites occurs along two parallel reaction pathways. The routes proposed include (i) the monofunctional hydrogenation of

Incense, sparklers and cigarettes are significant contributors to indoor benzene and particle levels

Directory of Open Access Journals (Sweden)

Werner Tirler

2015-03-01

Full Text Available Introduction. The increased use of incense, magic candles and other flameless products often produces indoor pollutants that may represent a health risk for humans. Today, in fact, incense and air fresheners are used inside homes as well as in public places including stores, shopping malls and places of worship. As a source of indoor contamination, the impact of smoke, incense and sparklers on human health cannot be ignored. Aim. In the present work, we report the results of an emission study regarding particles (PM10 and particle number concentration, PNC and benzene, produced by various incense sticks and sparklers. Results and discussion.The results obtained for benzene, PM10 and PNC, showed a strong negative influence on air quality when these products were used indoors. Various incense sticks gave completely different benzene results: from a small increase of the benzene concentration in the air, just slightly above the background levels of ambient air, to very high concentrations, of more than 200 µg/m³ of benzene in the test room after the incense sticks had been tested.

Incense, sparklers and cigarettes are significant contributors to indoor benzene and particle levels.

Science.gov (United States)

Tirler, Werner; Settimo, Gaetano

2015-01-01

The increased use of incense, magic candles and other flameless products often produces indoor pollutants that may represent a health risk for humans. Today, in fact, incense and air fresheners are used inside homes as well as in public places including stores, shopping malls and places of worship. As a source of indoor contamination, the impact of smoke, incense and sparklers on human health cannot be ignored. In the present work, we report the results of an emission study regarding particles (PM10 and particle number concentration, PNC) and benzene, produced by various incense sticks and sparklers. The results obtained for benzene, PM10 and PNC, showed a strong negative influence on air quality when these products were used indoors. Various incense sticks gave completely different benzene results: from a small increase of the benzene concentration in the air, just slightly above the background levels of ambient air, to very high concentrations, of more than 200 µg/m of benzene in the test room after the incense sticks had been tested.

Innovative approaches to remediation for VOC sites using recirculating wells

International Nuclear Information System (INIS)

Dawson, G.W.

1996-01-01

In-well air stripping with approaches such as the patented NoVOCs system offer both cost and operational advantages over pump and treat, and in situ air sparging technologies. With in-well stripping, the water is treated in the well and discharged without being brought to the surface. Discharged water is circulated through the saturated zone acting as a carrier to continually flush contaminants from the aquifer matrix and transport them to the well for treatment. With pumping rates up to four times those of comparable extraction wells, large radii of influence can be maintained and remediation is achieved faster and more efficiently. In-well stripping is applicable to any strippable contaminant including chlorinated solvents (i.e., TCE and PCE) and hydrocarbons such as the aromatic components in petroleum fuels. Growing costs associated with water discharge, NPDES permits, water rights and, in some areas, salt water intrusion have provided economic incentives to retrofit existing pump and treat systems with NoVOCs units. A large number of wells are amenable to retrofitting depending on their diameter, location and length of screens, and back fill. Even with the new initiatives for intrinsic remediation for petroleum fuel releases, there is a role for the NoVOCs technology. Free product removal wells based on the NoVOCs design eliminate the need to treat and permit water discharges produced when generating a cone of depression for collecting the floating fuel. Additionally, the stripping action and introduction of dissolved oxygen reduce soluble hydrocarbon concentrations to risk levels that can be easily addressed through intrinsic bioremediation

[Development of biogenic VOC emissions inventory with high temporal and spatial resolution].

Science.gov (United States)

Hu, Y; Zhang, Y; Xie, S; Zeng, L

2001-11-01

A new method was developed to estimate biogenic VOC emissions with high temporal and spatial resolution by use of Mesoscale Meteorology Modeling System Version5 (MM5). In this method, the isoprene and monoterpene standard emission factors for some types of tree in China were given and the standard VOC emission factors and seasonally average densities of leaf biomass for all types of vegetation were determined. A biogenic VOC emissions inventory in South China was established which could meet the requirement of regional air quality modeling. Total biogenic VOC emissions in a typical summer day were estimated to be 1.12 x 10(4) metric tons in an area of 729 km x 729 km of South China. The results showed the temporal and spatial distributions of biogenic VOC emission rates in this area. The results also showed that the geographical distribution of biogenic VOC emission rates depended on vegetation types and their distributions and the diurnal variation mainly depended on the solar radiation and temperature. The uncertainties of estimating biogenic VOC emissions were also discussed.

In situ synthesis of silver benzene-dithiolate hybrid films

Energy Technology Data Exchange (ETDEWEB)

Brenier, Roger, E-mail: roger.brenier@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Piednoir, Agnès, E-mail: agnes.piednoir@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Bertorelle, Franck, E-mail: franck.bertorelle@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Penuelas, José, E-mail: jose.penuelas@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France); Grenet, Geneviève, E-mail: genevieve.grenet@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France)

2016-02-01

In this article, a method for in situ synthesis of silver benzene-dithiolate hybrid films is presented. Silver nanoparticles, generated on ZrO{sub 2} films, are transformed into silver benzene 1,4-dithiolate or, partially, into silver benzene 1,2-dithiolate after sample immersion in the corresponding thiol solutions. These transformations occur at room temperature owing to the catalytic action of ZrO{sub 2}. It is also shown that TiO{sub 2} in place of ZrO{sub 2} is very efficient, both for the catalytic generation of silver nanoparticles and for their further transformation in benzene 1,4-dithiolate compound. This latter semiconductor has an optical bandgap of about 3 eV and the film is made of touching nanoparticles in an amorphous state. Our work has potential applications in the electronic and photovoltaic fields. - Highlights: • A method for in situ synthesis of silver benzene-dithiolate hybrid semiconductor films is presented. • Silver nanoparticles are, first, generated on ZrO{sub 2} or on TiO{sub 2} coated silica substrates. • The samples are immersed in benzene dithiol solution for two days at room temperature. • During the immersion, the silver nanoparticles are transformed into silver benzene dithiolate. • The silver benzene dithiolate film is made of amorphous nanoparticles with a banbgap of 3 eV.

Experimental and statistical characterization of Volatile Organic Compounds (VOC) within the ile-de-France region

International Nuclear Information System (INIS)

Baudic, Alexia

2016-01-01

Volatile organic compounds (VOCs) play a key role within the atmospheric system acting as precursors of ground-level ozone and secondary organic aerosols (causing health and climatic impacts); hence the growing interest of better characterizing them. Significant uncertainties are still associated with compounds speciation, quantification and respective contributions from the different emission sources. This thesis proposes, through several laboratory and intensive field campaigns, a detailed characterization of VOCs and their main emissions sources within the Ile-de-France region. We used methods based on the determination of speciation profiles indicative of road traffic, wood burning and natural gas sources obtained from near-field investigations (inside a tunnel, at a fireplace and from a domestic gas flue). These different source profiles were used as chemical fingerprints for the identification of the main VOC emission sources, which respective contributions were estimated using the Positive Matrix Factorization (PMF) source-receptor model applied to one-year VOCs (including NMHC+OVOC) measurements in Paris. This thesis allowed, for the first time, to evaluate the seasonal variability of VOCs and their main emission sources. Road traffic-related emissions are major VOC local/regional sources in Paris (contributing to a quarter of total annual emissions). The important impact of wood burning in winter (50 % of the VOC total mass) was observed. Results obtained from this approach were compared with the regional emissions inventory provided by the air quality monitoring network Airparif. Finally, a good agreement was found between our observations and the inventory for road traffic and wood burning-related sources. This independent assessment of inventories is of great interest because they are currently used as input data within air quality prediction models. (author) [fr

Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

DEFF Research Database (Denmark)

Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

2017-01-01

We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

Science.gov (United States)

Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

2017-09-01

Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

Reducing VOC Press Emission from OSB Manufacturing; FINAL

International Nuclear Information System (INIS)

Gary D, McGinnis; Laura S, WIlliams; Amy E, Monte; Jagdish Rughani; Brett A, Niemi; Thomas M, Flicker

2001-01-01

Current regulations require industry to meet air emission standards with regard to particulates, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and other gases. One of many industries that will be affected by the new regulations is the wood composites industry. This industry generates VOCs, HAPs, and particulates mainly during the drying and pressing of wood. Current air treatment technologies for the industry are expensive to install and operate. As regulations become more stringent, treatment technologies will need to become more efficient and cost effective. The overall objective of this study is to evaluate the use of process conditions and chemical additives to reduce VOC/HAPs in air emitted from presses and dryers during the production of oriented strand board

Inelastic X-ray scattering on liquid benzene analyzed using a generalized Langevin equation

Science.gov (United States)

Yoshida, Koji; Fukuyama, Nami; Yamaguchi, Toshio; Hosokawa, Shinya; Uchiyama, Hiroshi; Tsutsui, Satoshi; Baron, Alfred Q. R.

2017-07-01

The dynamic structure factor, S(Q,ω), of liquid benzene was measured by meV-resolved inelastic X-ray scattering (IXS) and analyzed using a generalized Langevin model with a memory function including fast, μ-relaxation and slow, structural, α-relaxation. The model well reproduced the experimental S(Q,ω) of liquid benzene. The dispersion relation of the collective excitation energy yields the high-frequency sound velocity for liquid benzene as related to the α-relaxation. The ratio of the high-frequency to the adiabatic sound velocity is approximately 1.5, larger to that of carbon tetrachloride and smaller than those of methanol and water, reflecting the nature of intermolecular interactions.

Combined analysis of job and task benzene air exposures among workers at four US refinery operations.

Science.gov (United States)

Burns, Amanda; Shin, Jennifer Mi; Unice, Ken M; Gaffney, Shannon H; Kreider, Marisa L; Gelatt, Richard H; Panko, Julie M

2017-03-01

Workplace air samples analyzed for benzene at four US refineries from 1976 to 2007 were pooled into a single dataset to characterize similarities and differences between job titles, tasks and refineries, and to provide a robust dataset for exposure reconstruction. Approximately 12,000 non-task (>180 min) personal samples associated with 50 job titles and 4000 task (job titles and task codes across all four refineries, and (5) our analysis of variance (ANOVA) of the distribution of benzene air concentrations for select jobs/tasks across all four refineries. The jobs and tasks most frequently sampled included those with highest potential contact with refinery product streams containing benzene, which reflected the targeted sampling approach utilized by the facility industrial hygienists. Task and non-task data were analyzed to identify and account for significant differences within job-area, task-job, and task-area categories. This analysis demonstrated that in general, areas with benzene containing process streams were associated with greater benzene air concentrations compared to areas with process streams containing little to no benzene. For several job titles and tasks analyzed, there was a statistically significant decrease in benzene air concentration after 1990. This study provides a job and task-focused analysis of occupational exposure to benzene during refinery operations, and it should be useful for reconstructing refinery workers' exposures to benzene over the past 30 years.

Novel collection method for volatile organic compounds (VOCs) from dogs

Science.gov (United States)

Host derived chemical cues are an important aspect of arthropod attraction to potential hosts. Host cues that act over longer distances include CO2, heat, and water vapor, while cues such as volatile organic compounds (VOCs) act over closer distances. Domestic dogs are important hosts for disease cy...

Microwave wood strand drying: energy consumption, VOC emission and drying quality

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Du, G.; Zhang, Y. [Tennessee Univ., Knoxville, TN (United States). Dept. of Forestry, Wildlife and Fisheries

2005-07-01

The objective of this research was to develop microwave drying technology for wood strand drying for oriented strand board (OSB) manufacturing. The advantages of microwave drying included a reduction in the drying time of wood strands and a reduction in the release of volatile organic compounds (VOC) through a decrease in the thermal degradation of the wood material. Temperature and moisture content changes under different microwave drying conditions were investigated. The effects of microwave drying on VOC emissions were evaluated and analyzed using gas chromatography and mass spectrometry. Microwave power input and the mass of drying materials in the microwave oven were found to have a dominant effect on drying quality. Results indicated that an increase in microwave power input and a decrease in sample weights resulted in high drying temperatures, short drying times and a high drying rate. The effect of microwave drying on the strand surfaces was also investigated. Different strand geometries and initial moisture content resulted in varying warm-up curves, but did not influence final moisture content. VOC emissions were quantified by comparing alpha-pinene concentrations. The microwave drying resulted in lower VOC emissions compared with conventional drying methods. It was concluded that the microwave drying technique provided faster strand drying and reduced energy consumption by up to 50 per cent. In addition, the surface wettability of wood strands dried with microwaves was better than with an industrial rotary drum drier. 12 refs., 3 tabs., 5 figs.

The solubilities of benzene polycarboxylic acids in water

International Nuclear Information System (INIS)

Apelblat, Alexander; Manzurola, Emanuel; Abo Balal, Nazmia

2006-01-01

The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

[Emission Characteristics of VOCs from Typical Restaurants in Beijing].

Science.gov (United States)

Cui, Tong; Cheng, Jing-chen; He, Wan-qing; Ren, Pei-fang; Nie, Lei; Xu, Dong-yao; Pan, Tao

2015-05-01

Using the EPA method, emission of volatile organic compounds (VOCs) , sampled from barbecue, Chinese and Western fast-food, Sichuan cuisine and Zhejiang cuisine restaurants in Beijing was investigated. VOCs concentrations and components from different cuisines were studied. The results indicated that based on the calibrated baseline ventilation volume, the VOCs emission level from barbecue was the highest, reaching 12.22 mg · m(-3), while those from fast-food of either Chinese or Western, Sichuan cuisine and Zhejiang cuisine were about 4 mg · m(-3). The components of VOCs from barbecue were different from those in the other cuisines, which were mainly propylene, 1-butene, n-butane, etc. The non-barbecue cuisines consisted of high concentration of alcohols, and Western fast-food contained relatively high proportion of aldehydes and ketones organic compounds. According to emission concentration of baseline ventilation volume, barbecue released more pollutants than the non-barbecue cuisines at the same scale. So, barbecue should be supervised and controlled with the top priority.

Concentrations and flux measurements of volatile organic compounds (VOC) in boreal forest soil

Science.gov (United States)

Mäki, Mari; Aaltonen, Hermanni; Heinonsalo, Jussi; Hellén, Heidi; Pumpanen, Jukka; Bäck, Jaana

2017-04-01

Volatile organic compounds (VOC) impact soil processes as VOCs transmit signals between roots and rhizosphere (Ditengou et al., 2015), VOCs can regulate microbial activity (Asensio et al., 2012), and VOCs can also promote root growth (Hung et al., 2012). Belowground concentrations of VOCs have not been measured in situ and for this reason, knowledge of how different soil organisms such as roots, rhizosphere and decomposers contribute to VOC production is limited. The aim of this study was to determine and quantify VOC fluxes and concentrations of different horizons from boreal forest soil. The VOC concentrations and fluxes were measured from Scots pine (Pinus sylvestris) forest soil at the SMEAR II station in southern Finland from 21th of April to 2nd of December in 2016. VOC fluxes were measured using dynamic (flow-through) chambers from five soil collars placed on five different locations. VOC concentrations were also measured in each location from four different soil horizons with the measurement depth 1-107 cm. VOCs were collected from underground gas collectors into the Tenax-Carbopack-B adsorbent tubes using portable pumps ( 100 ml min-1). The VOC concentrations and fluxes of isoprene, 11 monoterpenes, 13 sesquiterpenes and different oxygenated VOCs were measured. Sample tubes were analyzed using thermal desorption-gas chromatograph-mass spectrometry (TD-GC-MS). Soil temperature and soil water content were continuously monitored for each soil horizon. Our preliminary results show that the primary source of VOCs is organic soil layer and the contribution of mineral soil to the VOC formation is minor. VOC fluxes and concentrations were dominated by monoterpenes such as α-pinene, camphene, β-pinene, and Δ3-carene. Monoterpene concentration is almost 10-fold in organic soil compared to the deeper soil layers. However, the highest VOC fluxes on the soil surface were measured in October, whereas the monoterpene concentrations in organic soil were highest in July

Anaerobic benzene degradation under denitrifying conditions: Peptococcaceae was identified as dominant benzene degrader by Stable Isotope Probing (SIP)

NARCIS (Netherlands)

Zaan, van der B.M.; Talarico Saia, F.; Plugge, C.M.; Vos, de W.M.; Smidt, H.; Stams, A.J.M.; Langenhoff, A.A.M.; Gerritse, J.

2012-01-01

An anaerobic microbial community was enriched in a chemostat that was operated for more than 8 years with benzene and nitrate as electron acceptor. The coexistence of multiple species in the chemostat and the presence of a biofilm, led to the hypothesis that benzene-degrading species coexist in a

Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers

Science.gov (United States)

Rushton, L; Schnatter, A R; Tang, G; Glass, D C

2014-01-01

Background: High benzene exposure causes acute myeloid leukaemia (AML). Three petroleum case–control studies identified 60 cases (241 matched controls) for AML and 80 cases (345 matched controls) for chronic lymphoid leukaemia (CLL). Methods: Cases were classified and scored regarding uncertainty by two haematologists using available diagnostic information. Blinded quantitative benzene exposure assessment used work histories and exposure measurements adjusted for era-specific circumstances. Statistical analyses included conditional logistic regression and penalised smoothing splines. Results: Benzene exposures were much lower than previous studies. Categorical analyses showed increased ORs for AML with several exposure metrics, although patterns were unclear; neither continuous exposure metrics nor spline analyses gave increased risks. ORs were highest in terminal workers, particularly for Tanker Drivers. No relationship was found between benzene exposure and risk of CLL, although the Australian study showed increased risks in refinery workers. Conclusion: Overall, this study does not persuasively demonstrate a risk between benzene and AML. A previously reported strong relationship between myelodysplastic syndrome (MDS) (potentially previously reported as AML) at our study's low benzene levels suggests that MDS may be the more relevant health risk for lower exposure. Higher CLL risks in refinery workers may be due to more diverse exposures than benzene alone. PMID:24357793

(Liquid + liquid) equilibria of {benzene + cyclohexane + two ionic liquids} at different temperature and atmospheric pressure

International Nuclear Information System (INIS)

Sakal, Salem A.; Shen, Chong; Li, Chun-xi

2012-01-01

Highlights: ► (Liquid + liquid) equilibrium for two quaternary and two ternary systems were measured. ► The components include cyclohexane, benzene, [MIM][BF4], [MIM][ClO4] and [MMIM][DMP]. ► The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. ► Separation of benzene and cyclohexane by pure ILs and their mixtures were discussed. - Abstract: (Liquid + liquid) equilibrium data of the following ternary and quaternary systems at different temperatures and mass fractions of ionic liquids (ILs) were measured at atmospheric pressure, i.e., {cyclohexane + benzene + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])} at 298.2 K, {cyclohexane + benzene + 1-methylimidazolium tetrafluoroborate ([MIM][BF 4 ])} at 338.2 K, {cyclohexane + benzene + [MIM][BF 4 ] + [MMIM][DMP]} at (298.2 and 313.2) K, and {cyclohexane + benzene + 1-methylimidazolium perchlorate [MIM][ClO 4 ] + [MMIM][DMP]} at 298.2 K. The results indicate that both selectivity and distribution factor of the IL mixture for benzene are lower than that of pure IL [MMIM][DMP] at a specified condition, and decrease with the increase of the mass fraction of [MIM][BF 4 ] or [MIM][ClO 4 ] in its mixture of [MMIM][DMP] and the mole fraction of benzene. The extremely high selectivity of [MIM][BF 4 ] and [MIM][ClO 4 ] for aromatic compounds as predicted by the COSMOS-RS model is not justified by the present experimental results, and on the contrary, they show a relatively lower selectivity and extraction capacity for benzene than [MMIM][DMP].

Comparison of personal air benzene and urine t,t-muconic acid as a benzene exposure surrogate during turnaround maintenance in petrochemical plants.

Science.gov (United States)

Koh, Dong-Hee; Lee, Mi-Young; Chung, Eun-Kyo; Jang, Jae-Kil; Park, Dong-Uk

2018-04-12

Previous studies have shown that biomarkers of chemicals with long half-lives may be better surrogates of exposure for epidemiological analyses, leading to less attenuation of the exposure-disease association, than personal air samples. However, chemicals with short half-lives have shown inconsistent results. In the present study, we compared pairs of personal air benzene and its short-half-life urinary metabolite trans,trans-muconic acid (t,t-MA), and predicted attenuation bias of theoretical exposure-disease association. Total 669 pairs of personal air benzene and urine t,t-MA samples were taken from 474 male workers during turnaround maintenance operations held in seven petrochemical plants. Maintenance jobs were classified into 13 groups. Variance components were calculated for personal air benzene and urine t, t-MA separately to estimate the attenuation of the theoretical exposure-disease association. Personal air benzene and urine t, t-MA showed similar attenuation of the theoretical exposure-disease association. Analyses for repeated measurements showed similar results, while in analyses for values above the limits of detection (LODs), urine t, t-MA showed less attenuation of the theoretical exposure-disease association than personal air benzene. Our findings suggest that there may be no significant difference in attenuation bias when personal air benzene or urine t,t-MA is used as a surrogate for benzene exposure.

Emissions of Volatile Organic Compounds (VOCs) from Animal Husbandry: Chemical Compositions, Separation of Sources and Animal Types

Science.gov (United States)

Yuan, B.; Coggon, M.; Koss, A.; Warneke, C.; Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; De Gouw, J. A.

2016-12-01

Concentrated animal feeding operations (CAFOs) are important sources of volatile organic compounds (VOCs) in the atmosphere. We used a hydronium ion time-of-flight chemical ionization mass spectrometer (H3O+ ToF-CIMS) to measure VOC emissions from CAFOs in the Northern Front Range of Colorado during an aircraft campaign (SONGNEX) for regional contributions and from a mobile laboratory sampling for chemical characterizations of individual animal feedlots. The main VOCs emitted from CAFOs include carboxylic acids, alcohols, carbonyls, phenolic species, sulfur- and nitrogen-containing species. Alcohols and carboxylic acids dominate VOC concentrations. Sulfur-containing and phenolic species become more important in terms of odor activity values and NO3 reactivity, respectively. The high time-resolution mobile measurements allow the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the increase of ethanol concentrations were primarily associated with feed storage and handling. We apply a multivariate regression analysis using NH3 and ethanol as tracers to attribute the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls and carboxylic acids. Phenolic species and nitrogen-containing species are predominantly associated with animals and their waste. VOC ratios can be potentially used as indicators for the separation of emissions from dairy and beef cattle from the regional aircraft measurements.

The contribution of benzene to smoking-induced leukemia.

OpenAIRE

Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

2000-01-01

Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts t...

Benzene degradation in a denitrifying biofilm reactor

NARCIS (Netherlands)

Waals, van der Marcelle J.; Atashgahi, Siavash; Rocha, da Ulisses Nunes; Zaan, van der Bas M.; Smidt, Hauke; Gerritse, Jan

2017-01-01

Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more

Environmental and biological monitoring of benzene during self-service automobile refueling.

OpenAIRE

Egeghy, P P; Tornero-Velez, R; Rappaport, S M

2000-01-01

Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (...

Removal of VOCs from groundwater using membrane-assisted solvent extraction

International Nuclear Information System (INIS)

Hutter, J.C.; Vandegrift, G.F.; Nunez, L.; Redfield, D.H.

1992-01-01

A membrane-assisted solvent extraction (MASX) system coupled to a membrane-assisted distillation stripping (MADS) system for use in decontaminating groundwater is discussed. Volatile organic compounds (VOCs) are extracted in the MASX using a sunflower oil solvent. In the MADS, VOCs are stripped from the sunflower oil, and the oil is recycled to the MASX. Thermodynamic data for the sunflower oil-water-VOCs system were experimentally collected. Published membrane-mass transfer results along with these data were used to design the MASX and MADS modules

Feasibility Analysis of Sustainability-Based Measures to Reduce VOC Emissions in Office Partition Manufacturing

Directory of Open Access Journals (Sweden)

Marc A. Rosen

2010-02-01

Full Text Available A feasibility analysis is reported of reduction opportunities for volatile organic compound (VOC emissions in manufacturing office furniture partitions, aimed at contributing to efforts to improve the sustainability of the process. A pollution prevention methodology is utilized. The purpose is to provide practical options for VOC emissions reductions during the manufacturing of office furniture partitions, but the concepts can be generally applied to the wood furniture industry. Baseline VOC emissions for a typical plant are estimated using a mass balance approach. The feasibility analysis expands on a preliminary screening to identify viable pollution prevention options using realistic criteria and weightings, and is based on technical, environmental and economic considerations. The measures deemed feasible include the implementation of several best management practices, ceasing the painting of non-visible parts, switching to hot melt backwrapping glue, application of solvent recycling and modification of the mechanical clip attachment. Implementation, measurement and control plans are discussed for the measures considered feasible, which can enhance the sustainability of the manufacturing of office furniture partitions. Reducing VOC emissions using the measures identified can, in conjunction with other measures, improve the sustainability of the manufacturing process.

Influence of benzene emission from motorcycle on Bangkok air quality

Science.gov (United States)

Leong, Shing Tet; Muttamara, S.; Laortanakul, Preecha

This study investigated the influence of benzene concentration from motorcycle exhaust emissions on ambient air quality in Bangkok Metropolitan Region (BMR). Measurement of benzene concentration in exhaust emissions is performed on a standard test driving cycle through which each motorcycle to be tested is driven. The test result revealed that average benzene concentrations in exhaust emission for the test motorcycles ranged from 3.02 to 109.68 mg/m 3. The finding also indicated that two-stroke motorcycles emitted five times more benzene than that of four-stroke motorcycles. Four air monitoring sites were strategically established to determine the relationship between average benzene concentrations with different traffic configurations in each traffic zone of BMR during peak/non-peak hours, day/night times and weekday/weekend. The shape of the curve for benzene level usually shows two peaks corresponding to the morning and evening traffic rush or commuter rush hours. The finding shows that the mean concentrations for benzene in all monitoring stations in the ambient air for peak hours (07:00-09:00 and 16:00-18:00 h) ranged from 15.1 to 42.4 μg/m 3. For non-peak hour (11:30-15:00 h), benzene levels were found in the range 16.3-30.9 μg/m 3. It is observed that higher levels of benzene are found among roadside stations with slow moving traffic while lower levels are found among roadside stations with fast traffic movement. Additional factors such as temperature, wind speed, rainfall, etc. are also considered in this study to determine the relationship between traffic conditions and ambient benzene levels.

Investigation of VOC emissions from indoor and outdoor painting processes in shipyards

Science.gov (United States)

Celebi, Ugur Bugra; Vardar, Nurten

Volatile organic compounds (VOCs) from painting solvents are one of the most important sources of pollutant outputs for the shipbuilding and ship repair industry. Two ships of equal tonnage with the same painted area as each other, which were built in Turkish shipyards, are compared in terms of VOCs produced during painting and coating. Total area of all painted surfaces and total paint consumption of a 3500 deadweight tonne (DWT) oil/chemical tanker and a general cargo ship are calculated. An improved model for calculating the surface emissions of VOCs from painting and coating processes is utilized. Material balance emission estimation approach is employed to calculate the amount of VOCs, since it is used most often where a relatively large amount of material is emitted during use, and/or all air emissions are uncaptured. For both ships calculated VOCs are presented in figures. For the years 2005 and 2006 the total deadweight tonnage of ships delivered in Tuzla region, where 42 shipyards are located, is known. Therefore, a linear estimation is made to guess the total annual VOC emissions caused by painting operations. Finally, this information is used to project the total amount of VOCs emitted to the atmosphere for the year 2010.

VOC-Arid Integrated Demonstration guide to preparation of demonstration documents

International Nuclear Information System (INIS)

Jensen, E.J.; Brouns, T.M.; Koegler, K.J.; McCabe, G.H.; Morris, F.A.

1994-06-01

This guide has been prepared by Demonstration Operations of the Volatile Organic Compound-Arid Integrated Demonstration (VOC-Arid ID). Its purpose is to describe demonstration documents, designate responsibilities for these documents, and guide the Principal Investigator (PI) and others in their preparation. The main emphasis of this guide is to describe the documentation required of the PI. However, it does cover some of the responsibilities of other members of the VOC-Arid ID team. The VOC-Arid ID is one of several US Department of Energy (DOE) integrated demonstrations designed to support the demonstration of emerging environmental management and restoration technologies. The principal objective of the VOC-Arid ID is to identify, develop, and demonstrate new and innovative technologies for environmental restoration at arid or semiarid sites containing volatile organic compounds with or without associated contamination (e.g., radionuclides and metals)

PTR-MS as a technique for investigating stress induced emission of biogenic VOCS

International Nuclear Information System (INIS)

Beauchamp, J.; Hansel, A.; Wisthaler, A.; Kleist, E.; Miebach, M.; Weller, U.; Wildt, J.

2004-01-01

Proton-transfer-reaction mass spectrometry (PTR-MS) was used in conjunction with two GC-MS systems to investigate stress induced emissions of volatile organic compounds (VOCs) from plants. Experiments were performed in the laboratory under well defined conditions and VOC emissions were induced by ozone exposure at variable concentrations and for different durations. Tobacco (Nicotiana tabaccum cv. Bel W3) plants were used as the investigated species. This investigation demonstrated the ability of PTR-MS to provide excellent high time-resolution on-line measurements of the relevant species. The combination of the PTR-MS instrument with the two GC-MS systems (which enabled accurate compound identification) allowed for detailed investigation of the dynamics of the plants' responses to ozone stress. VOCs measured included methanol, C6- alcohols and aldehydes, methyl salicylate and sesquiterpenes. Results indicate that the temporal stress response of plants depend on the amount of stress encountered by the plant. Measurement technique and experimental results will be presented. (author)

Evaluation of the potential of volatile organic compound (di-methyl benzene) removal using adsorption on natural minerals compared to commercial oxides

Energy Technology Data Exchange (ETDEWEB)

Zaitan, Hicham, E-mail: hicham.zaitan@usmba.ac.ma [Laboratory LCMC, Faculty of Sciences and Techniques, University Sidi Mohamed BenAbdellah, B.P. 2202, Fez (Morocco); Korrir, Abdelhamid; Chafik, Tarik [Laboratory LGCVR, Faculty of Sciences and Techniques, University Abdelmalek Essaadi, B.P. 416, Tangier (Morocco); Bianchi, Daniel [Institut de Recherche sur la Catalyse et l’Environnement de Lyon (IRCELYON), UMR 5256 CNRS, University Claude Bernard Lyon I, Bat. Chevreul, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne (France)

2013-11-15

Highlights: • The adsorption of dMB on natural minerals and commercial oxides was evaluated. • The adsorption capacities were discussed considering the adsorbents cost and the bed size. • The adsorption capacity of bentonite is higher than other adsorbents. • Langmuir model provide best correlation of the experimental data. • The isotherms data allow determination of isosteric heat of adsorption. -- Abstract: This study is dedicated to the investigation of the potential of volatile organic compounds (VOC) adsorption over low cost natural minerals (bentonite and diatomite). The performances of these solids, in terms of adsorption/desorption properties, were compared to commercial adsorbents, such as silica, alumina and titanium dioxide. The solids were first characterized by different physico-chemical methods and di-methyl benzene (dMB) was selected as model VOC pollutant for the investigation of adsorptive characteristics. The experiments were carried out with a fixed bed reactor under dynamic conditions using Fourier Transform InfraRed spectrometer to measure the evolution of dMB concentrations in the gaseous stream at the outlet of the reactor. The measured breakthrough curves yields to adsorbed amounts at saturation that has been used to obtain adsorption isotherms. The latters were used for determination of the heat involved in the adsorption process and estimation of its values using the isosteric method. Furthermore, the performances of the studied materials were compared considering the adsorption efficiency/cost ratio.

Evaluation of the potential of volatile organic compound (di-methyl benzene) removal using adsorption on natural minerals compared to commercial oxides

International Nuclear Information System (INIS)

Zaitan, Hicham; Korrir, Abdelhamid; Chafik, Tarik; Bianchi, Daniel

2013-01-01

Highlights: • The adsorption of dMB on natural minerals and commercial oxides was evaluated. • The adsorption capacities were discussed considering the adsorbents cost and the bed size. • The adsorption capacity of bentonite is higher than other adsorbents. • Langmuir model provide best correlation of the experimental data. • The isotherms data allow determination of isosteric heat of adsorption. -- Abstract: This study is dedicated to the investigation of the potential of volatile organic compounds (VOC) adsorption over low cost natural minerals (bentonite and diatomite). The performances of these solids, in terms of adsorption/desorption properties, were compared to commercial adsorbents, such as silica, alumina and titanium dioxide. The solids were first characterized by different physico-chemical methods and di-methyl benzene (dMB) was selected as model VOC pollutant for the investigation of adsorptive characteristics. The experiments were carried out with a fixed bed reactor under dynamic conditions using Fourier Transform InfraRed spectrometer to measure the evolution of dMB concentrations in the gaseous stream at the outlet of the reactor. The measured breakthrough curves yields to adsorbed amounts at saturation that has been used to obtain adsorption isotherms. The latters were used for determination of the heat involved in the adsorption process and estimation of its values using the isosteric method. Furthermore, the performances of the studied materials were compared considering the adsorption efficiency/cost ratio

POLLUTION PREVENTION CASE STUDIES: LOW-VOC/HAP WOOD FURNITURE COATINGS

Science.gov (United States)

This article provides a brief profile of the wood furniture industry, discusses pollution prevention activities typically implemented, describes the four low-VOC/HAP coating technologies studied. and summarizes one case study for each of the low-VOC/HAP coating yechnologies inves...

A cohort study of intra-urban variations in volatile organic compounds and mortality, Toronto, Canada.

Science.gov (United States)

Villeneuve, Paul J; Jerrett, Michael; Su, Jason; Burnett, Richard T; Chen, Hong; Brook, Jeffrey; Wheeler, Amanda J; Cakmak, Sabit; Goldberg, Mark S

2013-12-01

This study investigated associations between long-term exposure to ambient volatile organic compounds (VOCs) and mortality. 58,760 Toronto residents (≥35 years of age) were selected from tax filings and followed from 1982 to 2004. Death information was extracted using record linkage to national mortality data. Land-use regression surfaces for benzene, n-hexane, and total hydrocarbons were generated from sampling campaigns in 2002 and 2004 and assigned to residential addresses in 1982. Cox regression was used to estimate relationships between each VOC and non-accidental, cardiovascular, and cancer mortality. Positive associations were observed for each VOC. In multi-pollutant models the benzene and total hydrocarbon signals were strongest for cancer. The hazard ratio for cancer that corresponded to an increase in the interquartile range of benzene (0.13 μg/m(3)) was 1.06 (95% CI = 1.02-1.11). Our findings suggest ambient concentrations of VOCs were associated with cancer mortality, and that these exposures did not confound our previously reported associations between NO2 and cardiovascular mortality. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Report from Workshop on VOCs in diving chambers

International Nuclear Information System (INIS)

Crosbie, A.; Simpson, M.

2000-05-01

This report of the 'Setting the Standards' workshop on the problems of volatile organic compounds (VOCs) in diving in offshore operations, sponsored jointly by the UK Health and Safety Executive Offshore Safety Division and the Stolt Rockwater Joint Venture, gives details of the papers presented covering the chemical contamination of diver's atmosphere, sampling protocols and methods, analytical procedures used for VOCs in hyperbaric chambers, and contamination in buildings. The setting of exposure limits in the UK, the derivation of threshold limiting values (TVLs), the selection of Tenax tubes for atmospheric sampling, organic contaminant monitoring, and NASA's approach to contamination in the space environment are examined, and dealing with contamination problems in a submarine atmosphere, and the simulation of a condensate spillage in a diving bell are discussed. Guidelines for the measurement of VOCs in hyperbaric chambers are given in the appendices

Rapid detection of pathogenic bacteria by volatile organic compound (VOC) analysis

Science.gov (United States)

Senecal, Andre G.; Magnone, Joshua; Yeomans, Walter; Powers, Edmund M.

2002-02-01

Developments in rapid detection technologies have made countless improvements over the years. However, because of the limited sample that these technologies can process in a single run, the chance of capturing and identifying a small amount of pathogens is difficult. The problem is further magnified by the natural random distribution of pathogens in foods. Methods to simplify pathogenic detection through the identification of bacteria specific VOC were studied. E. coli O157:H7 and Salmonella typhimurium were grown on selected agar medium to model protein, and carbohydrate based foods. Pathogenic and common spoilage bacteria (Pseudomonas and Morexella) were screened for unique VOC production. Bacteria were grown on agar slants in closed vials. Headspace sampling was performed at intervals up to 24 hours using Solid Phase Micro-Extraction (SPME) techniques followed by GC/MS analysis. Development of unique volatiles was followed to establish sensitivity of detection. E. coli produced VOC not found in either Trypticase Soy Yeast (TSY) agar blanks or spoilage organism samples were - indole, 1-decanol, and 2-nonanone. Salmonella specific VOC grown on TSY were 3-methyl-1-butanol, dimethyl sulfide, 2-undecanol, 2-pentadecanol and 1-octanol. Trials on potato dextrose agar (PDA) slants indicated VOC specific for E. coli and Salmonella when compared to PDA blanks and Pseudomonas samples. However, these VOC peaks were similar for both pathogens. Morexella did not grow on PDA slants. Work will continue with model growth mediums at various temperatures, and mixed flora inoculums. As well as, VOC production based on the dynamics of bacterial growth.

Benzene biodegradation using an anaerobic column coupled to Mn(IV) reduction

Energy Technology Data Exchange (ETDEWEB)

Villatoro-Monzon, W.R.; Velasquez-Mejia, E.K.; Morales-Ibarria, M.G.; Razo-Flores, E. [Instituto Mexicano del Petroleo (Mexico). Programo de Biotenologia del Petroleo

2004-07-01

Benzene, toluene, and o, m, p-xylene compounds make up a large proportion of gasoline. Due to spills and leaks from underground tanks, these compounds frequently contaminate groundwater and sediment. In particular the high solubility of benzene makes it very mobile and an extra danger to groundwater. Moreover, there are strong links between benzene and cancer and thus benzene is considered a serious pollutant. Contaminated sites usually become anaerobic due to microbe action. In this study, benzene biodegradation was done in a glass column inoculated with anaerobic Rhine River sediment and using Mn(IV) as the final electron acceptor. Under steady state operation, benzene biodegradation efficiency was as high as 95 per cent. Carbon dioxide and Mn(II) recovery rates were 81 and 77 per cent respectively. Reactor sediment was withdrawn on day 104 and subject to DGGE profiling. This sediment showed different band patterns than the original sediment that was not exposed to benzene. The authors conclude that the species associated with the degradation of benzene are of the genus Propionibacterium and Actinomyces. 17 refs., 2 figs.

Meta-analysis of benzene exposure and non-Hodgkin lymphoma: biases could mask an important association

Science.gov (United States)

Steinmaus, C; Smith, A H; Jones, R M; Smith, M T

2015-01-01

Objectives Benzene is a widely recognised cause of leukaemia but its association with non-Hodgkin’s lymphoma (NHL) is less well established. The goal of this project is to review the current published literature on this association. Methods We performed a meta-analysis of cohort and case-control studies of benzene exposure and NHL and a meta-analysis of NHL and refinery work, a potential source of benzene exposure. Results In 22 studies of benzene exposure, the summary relative risk for NHL was 1.22 (95% CI 1.02 to 1.47; one-sided p value = 0.01). When studies that likely included unexposed subjects in the “exposed” group were excluded, the summary relative risk increased to 1.49 (95% CI 1.12 to 1.97, n = 13), and when studies based solely on self-reported work history were excluded, the relative risk rose to 2.12 (95% CI 1.11 to 4.02, n = 6). In refinery workers, the summary relative risk for NHL in all 21 studies was 1.21 (95% CI 1.00 to 1.46; p = 0.02). When adjusted for the healthy worker effect, this relative risk estimate increased to 1.42 (95% CI 1.19 to 1.69). Conclusions The finding of elevated relative risks in studies of both benzene exposure and refinery work provides further evidence that benzene exposure causes NHL. In addition, the finding of increased relative risks after removing studies that included unexposed or lesser exposed workers in “exposed” cohorts, and increased relative risk estimates after adjusting for the healthy worker effect, suggest that effects of benzene on NHL might be missed in occupational studies if these biases are not accounted for. PMID:18417556

Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

Science.gov (United States)

Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

2015-01-01

The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

A comprehensive study of benzene concentrations and emissions in Houston

Science.gov (United States)

Müller, Markus; Eichler, Philipp; Berk Knighton, W.; Estes, Mark; Crawford, James H.; Mikoviny, Tomas; Wisthaler, Armin

2014-05-01

The Houston Metropolitan Area (Greater Houston) has a population of over 6 million people, it ranks among the three fastest growing metropolises in the developed world and population growth scenarios predict it to reach megacity status in the coming two to four decades. Greater Houston is home to the largest petrochemical-manufacturing complex in the world with important consequences for the environment in the region. Direct and fugitive emissions of hydrocarbons adversely affect Houston's air quality which has been subject to intense studies over the past two decades. In 2013, NASA conducted the DISCOVER-AQ field campaign in support of developing a satellite-based capability to assess Houston's air quality in the future. Amongst other measurements, airborne, mobile ground-based and stationary ground-based measurements of benzene were carried out. Benzene is a carcinogenic air toxic with strict exposure regulations in the U.S. and in Europe. We have used the obtained comprehensive dataset to map benzene concentrations in the Houston metropolitan area, locate and identify point sources, compare industrial and traffic emissions and put them in relation to previous measurements and emission inventories. The obtained data will allow a better assessment of health risks associated with benzene exposure in a large metropolitan area that includes both traffic and industrial benzene sources. This work was funded by BMVIT / FFG-ALR in the frame of the Austrian Space Application Programme (ASAP 8, project 833451). PE was funded through the PIMMS ITN (EU-FP7, agreement number 287382). Additional resources were provided through NASA's Earth Venture program (EV-1) and the NASA Postdoctoral Program (NPP). We want to thank Scott Herndon and Aerodyne Research for their support.

Emission characteristics of VOCs emitted from consumer and commercial products and their ozone formation potential.

Science.gov (United States)

Dinh, Trieu-Vuong; Kim, Su-Yeon; Son, Youn-Suk; Choi, In-Young; Park, Seong-Ryong; Sunwoo, Young; Kim, Jo-Chun

2015-06-01

The characteristics of volatile organic compounds (VOCs) emitted from several consumer and commercial products (body wash, dishwashing detergent, air freshener, windshield washer fluid, lubricant, hair spray, and insecticide) were studied and compared. The spray products were found to emit the highest amount of VOCs (~96 wt%). In contrast, the body wash products showed the lowest VOC contents (~1.6 wt%). In the spray products, 21.6-96.4 % of the VOCs were propane, iso-butane, and n-butane, which are the components of liquefied petroleum gas. Monoterpene (C10H16) was the dominant component of the VOCs in the non-spray products (e.g., body wash, 53-88 %). In particular, methanol was present with the highest amount of VOCs in windshield washer fluid products. In terms of the number of carbon, the windshield washer fluids, lubricants, insecticides, and hair sprays comprised >95 % of the VOCs in the range C2-C5. The VOCs in the range C6-C10 were predominantly found in the body wash products. The dishwashing detergents and air fresheners contained diverse VOCs from C2 to C11. Besides comprising hazardous VOCs, VOCs from consumer products were also ozone precursors. The ozone formation potential of the consumer and commercial spray products was estimated to be higher than those of liquid and gel materials. In particular, the hair sprays showed the highest ozone formation potential.

Determination of residual volatile organic compounds migrated from polystyrene food packaging into food simulant by headspace solid phase micro extraction-gas chromatography

International Nuclear Information System (INIS)

Mohd Marsin Sanagi; Ling, Susie Lu; Zalilah Nasir; Wan Aini Wan Ibrahim; Abu Naim, Ahmedy

2008-01-01

The residual styrene and other volatile organic compounds (VOCs) present in the polystyrene food packaging are of concern as these compounds have the potential to migrate into the food in contact. This work describes a method for quantitative determination of VOCs, namely styrene, toluene, ethyl benzene, iso-propylbenzene and n-propylbenzene that have migrated from polystyrene food packaging into food stimulant by gas chromatography-flame ionization detection (GC-FID). Headspace solid phase micro extraction (HS-SPME) technique was applied for migration test using water as food stimulant. The effects of extraction variables including sample volume, eluotropic strength, extraction temperature, extraction time, desorption time, sample agitation, and salt addition on the amounts of the extracted analyses were studied to obtain the optimal HS-SPME conditions. The optimized method was applied to test the VOCs migrated from polystyrene bowls and cups at storage temperatures ranging from 24 to 80 degree Celsius for 30 min. Styrene and ethyl benzene were found to migrate from the samples into the food stimulant. The migration of analyze was found to be strongly dependent upon the storage temperature. The HS-SPME is useful as an alternative method to determine the migration of VOCs from food packaging material into food stimulant. (author)

The safety of non-incineration waste disposal devices in four hospitals of Tehran

Science.gov (United States)

Farshad, Aliasghar; Gholami, Hamid; Farzadkia, Mahdi; Mirkazemi, Roksana; Kermani, Majid

2014-01-01

Background: The safe management of hospital waste is a challenge in many developing countries. Objectives: The aim of this study was to compare volatile organic compounds (VOCs) emissions and the microbial disinfectant safety in non-incineration waste disposal devices. Methods: VOC emissions and microbial infections were measured in four non-incineration waste disposal devices including: autoclave with and without a shredder, dry heat system, and hydroclave. Using NIOSH and US EPA-TO14 guidelines, the concentration and potential risk of VOCs in emitted gases from four devices were assessed. ProSpore2 biological indicators were used to assess the microbial analysis of waste residue. Results: There was a significant difference in the type and concentration of VOCs and microbial infection of residues in the four devices. Emissions from the autoclave with a shredder had the highest concentration of benzene, ethyl benzene, xylene, and BTEX, and emissions from the hydroclave had the highest concentration of toluene. The highest level of microbial infection was observed in the residues of the autoclave without a shredder. Conclusions: There is an increased need for proper regulation and control of non-incinerator devices and for monitoring and proper handling of these devices in developing countries. PMID:25000113

Mobile membrane introduction tandem mass spectrometry for on-the-fly measurements and adaptive sampling of VOCs around oil and gas projects in Alberta, Canada

Science.gov (United States)

Krogh, E.; Gill, C.; Bell, R.; Davey, N.; Martinsen, M.; Thompson, A.; Simpson, I. J.; Blake, D. R.

2012-12-01

The release of hydrocarbons into the environment can have significant environmental and economic consequences. The evolution of smaller, more portable mass spectrometers to the field can provide spatially and temporally resolved information for rapid detection, adaptive sampling and decision support. We have deployed a mobile platform membrane introduction mass spectrometer (MIMS) for the in-field simultaneous measurement of volatile and semi-volatile organic compounds. In this work, we report instrument and data handling advances that produce geographically referenced data in real-time and preliminary data where these improvements have been combined with high precision ultra-trace VOCs analysis to adaptively sample air plumes near oil and gas operations in Alberta, Canada. We have modified a commercially available ion-trap mass spectrometer (Griffin ICX 400) with an in-house temperature controlled capillary hollow fibre polydimethylsiloxane (PDMS) polymer membrane interface and in-line permeation tube flow cell for a continuously infused internal standard. The system is powered by 24 VDC for remote operations in a moving vehicle. Software modifications include the ability to run continuous, interlaced tandem mass spectrometry (MS/MS) experiments for multiple contaminants/internal standards. All data are time and location stamped with on-board GPS and meteorological data to facilitate spatial and temporal data mapping. Tandem MS/MS scans were employed to simultaneously monitor ten volatile and semi-volatile analytes, including benzene, toluene, ethylbenzene and xylene (BTEX), reduced sulfur compounds, halogenated organics and naphthalene. Quantification was achieved by calibrating against a continuously infused deuterated internal standard (toluene-d8). Time referenced MS/MS data were correlated with positional data and processed using Labview and Matlab to produce calibrated, geographical Google Earth data-visualizations that enable adaptive sampling protocols

Origin of 2-ethylhexanol as a VOC

International Nuclear Information System (INIS)

Nalli, Sandro; Horn, Owen J.; Grochowalski, Adam R.; Cooper, David G.; Nicell, Jim A.

2006-01-01

2-Ethylhexanol has been identified as a volatile organic compound (VOC) that contributes to the deterioration of indoor air quality. Plasticizers are common components of dust and building materials and are shown to be degraded by a variety of bacteria and fungi to produce 2-ethyhexanol and other metabolites. Of these, the 2-ethylhexanol has significant volatility and was observed in appreciable quantities. The degree to which 2-ethylhexanol is observed as a VOC in air samples would be limited by the fact that many of the microorganisms that are capable of producing this compound are also able to oxidize it to 2-ethylhexanoic acid, which is much less volatile. It is argued that an abiotic degradation mechanism of plasticizers that results in the generation of 2-ethylhexanol is unlikely and, if this did occur, other metabolites should have been observed. Thus, the microbial degradation of plasticizers is the most likely source of 2-ethylhexanol in indoor air. - A link has been observed between the partial biodegradation of plasticizers by microorganisms and VOCs associated with poor indoor air quality

Major reactive species of ambient volatile organic compounds (VOCs) and their sources in Beijing

Institute of Scientific and Technical Information of China (English)

SHAO; Min; FU; Linlin; LIU; Ying; LU; Sihua; ZHANG; Yuanhan

2005-01-01

Volatile organic compounds (VOCs) are important precursors of atmospheric chemical processes. As a whole mixture, the ambient VOCs show very strong chemical reactivity. Based on OH radical loss rates in the air, the chemical reactivity of VOCs in Beijing was calculated. The results revealed that alkenes, accounting for only about 15% in the mixing ratio of VOCs, provide nearly 75% of the reactivity of ambient VOCs and the C4 to C5 alkenes were the major reactive species among the alkenes. The study of emission characteristics of various VOCs sources indicated that these alkenes are mainly from vehicle exhaust and gasoline evaporation. The reduction of alkene species in these two sources will be effective in photochemical pollution control in Beijing.

Investigation of the behavior of VOCs in ground water across fine- and coarse-grained geological contacts using a medium-scale physical model

Energy Technology Data Exchange (ETDEWEB)

Hoffman, F.; Chiarappa, M.L.

1998-03-01

One of the serious impediments to the remediation of ground water contaminated with volatile organic compounds (VOCs) is that the VOCs are retarded with respect to the movement of the ground water. Although the processes that result in VOC retardation are poorly understood, we have developed a conceptual model that includes several retarding mechanisms. These include adsorption to inorganic surfaces, absorption to organic carbon, and diffusion into areas of immobile waters. This project was designed to evaluate the relative contributions of these mechanisms; by improving our understanding, we hope to inspire new remediation technologies or approaches. Our project consisted of a series of column experiments designed to measure the retardation, in different geological media, of four common ground water VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) which have differing physical and chemical characteristics. It also included a series of diffusion parameters that constrain the model, we compared the data from these experiments to the output of a computational model.

Removal of VOCs by hybrid electron beam reactor with catalyst bed

International Nuclear Information System (INIS)

Kim, Jinkyu; Han, Bumsoo; Kim, Yuri; Lee, J.H.; Park, C.R.; Kim, J.C.; Kim, J.C.; Kim, K.J.

2004-01-01

Electron beam decomposition of volatile organic compounds (VOCs) was studied in order to obtain information for developing effective treatment method of off-gases from industries. We have examined the combination of electron beam and catalyst honeycomb which is either 1% platinum based or ceramic honeycomb- based aluminum oxide, using a hybrid reactor in order to improve removal efficiency and CO 2 formation; and to suppress undesirable by-product formation e.g. O 3 , aerosol, H x C y. , and tar. The experiments were conducted using a pilot-scale treatment system (maximum capacity; 1800 N m 3 /h) that fitted the field size to scale up from the traditional laboratory scale system for VOC removal with electron beam irradiation. Toluene was selected as a typical VOC that was irradiated to investigate product formation, effect of ceramic and catalyst, and factors effecting overall efficiency of degradation. Styrene was selected as the most odorous compound among the VOCs of interest. It was found that VOCs could be destroyed more effectively using a hybrid system with catalyst bed than with electron beam irradiation only

Assessment of the reduction methods used to develop chemical schemes: building of a new chemical scheme for VOC oxidation suited to three-dimensional multiscale HOx-NOx-VOC chemistry simulations

Directory of Open Access Journals (Sweden)

S. Szopa

2005-01-01

Full Text Available The objective of this work was to develop and assess an automatic procedure to generate reduced chemical schemes for the atmospheric photooxidation of volatile organic carbon (VOC compounds. The procedure is based on (i the development of a tool for writing the fully explicit schemes for VOC oxidation (see companion paper Aumont et al., 2005, (ii the application of several commonly used reduction methods to the fully explicit scheme, and (iii the assessment of resulting errors based on direct comparison between the reduced and full schemes. The reference scheme included seventy emitted VOCs chosen to be representative of both anthropogenic and biogenic emissions, and their atmospheric degradation chemistry required more than two million reactions among 350000 species. Three methods were applied to reduce the size of the reference chemical scheme: (i use of operators, based on the redundancy of the reaction sequences involved in the VOC oxidation, (ii grouping of primary species having similar reactivities into surrogate species and (iii grouping of some secondary products into surrogate species. The number of species in the final reduced scheme is 147, this being small enough for practical inclusion in current three-dimensional models. Comparisons between the fully explicit and reduced schemes, carried out with a box model for several typical tropospheric conditions, showed that the reduced chemical scheme accurately predicts ozone concentrations and some other aspects of oxidant chemistry for both polluted and clean tropospheric conditions.

Summary and findings: Chapter A

Science.gov (United States)

Maslia, Morris L.; Suárez-Soto, René J.; Sautner, Jason B.; Anderson, Barbara A.; Jones, L. Elliott; Faye, Robert E.; Aral, Mustafa M.; Guan, Jiabao; Jang, Wonyong; Telci, Ilker T.; Grayman, Walter M.; Bove, Frank J.; Ruckart, Perri Z.; Moore, Susan M.

2013-01-01

The Agency for Toxic Substances and Disease Registry (ATSDR) is conducting epidemiological studies to evaluate the potential for health effects from exposures to volatile organic compounds (VOCs) in finished water supplied to family housing units at U.S. Marine Corps Base Camp Lejeune, North Carolina (USMCB Camp Lejeune). The core period of interest for the epidemiological studies is 1968– 1985. VOCs of major interest to the epidemiological studies include tetrachloroethylene (PCE), trichloroethylene (TCE), trans-1,2-dichloroethylene (1,2-tDCE), vinyl chloride (VC), and benzene.

Physiological and phylogenetic characterization of a stable benzene-degrading, chlorate-reducing microbial community

NARCIS (Netherlands)

Weelink, S.A.B.; Tan, N.C.G.; Broeke, H. ten; Doesburg, W. van; Langenhoff, A.A.M.; Gerritse, J.; Stams, A.J.M.

2007-01-01

A stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20-1650 times higher than reported for anaerobic benzene

Breakthrough indicator for aromatic VOCs using needle trap samplers for activated carbon adsorbent.

Science.gov (United States)

Cheng, Wen-Hsi; Jiang, Jia-Rong; Huang, Yi-Ning; Huang, Shiun-Chian; Yu, Yan-Pin

2012-08-01

Internal circulation cabinets equipped with granular activated carbon (GAC) for adsorbing volatile organic compounds (VOCs) are widely used to store bottles containing organic solvents in universities, colleges, and hospital laboratories throughout Taiwan. This work evaluates the VOC adsorption capacities of GAC using various adsorption times for gas stream mixtures of 100 ppm toluene and 100 ppm o-xylene. Additionally, needle trap sampling (NTS) technology was used to indicate the time for renewing the GAC to avoid VOC breakthrough from adsorbents. Experimental results demonstrate that the proposed models can linearly express toluene and o-xylene adsorption capacities as the natural logarithm of adsorption time (ln(t)) and can accurately simulate the equilibrium adsorption capacities (Qe, g VOCs/g GAC) for gaseous toluene and o-xylene. The NTS, packed with 60-80 mesh divinylbenzene (DVB) particles, was compared in terms of extraction efficiency by simultaneously using the 75-microm Carboxen/polydimethylsiloxane-solid-phase microextraction (Carboxen/PDMS-SPME) fiber for time-weighted average (TWA) sampling, and experimental results indicated that the packed DVB-NTS achieved higher toluene extraction rates. Additionally, the NTS installed in the outlet air stream for adsorbing toluene and o-xylene exhausted through GAC accurately indicated toluene and o-xylene breakthrough times of 4700-5000 min. The GAC-NTS operational instructions to indicate the replacing time of adsorbent in the internal circulation cabinets are also included in this paper.

Evaluation of impact factors on VOC emissions and concentrations from wooden flooring based on chamber tests

Energy Technology Data Exchange (ETDEWEB)

Lin, Chi-Chi [Department of Civil and Environmental Engineering, National University of Kaohsiung, No. 700, Kaohsiung University Rd., Kaohsiung (China); Yu, Kuo-Pin [Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, No.155, Sec.2, Linong Street, Taipei (China); Zhao, Ping [Filtration Group Inc., 912 E. Washington Street, Joliet, IL 60433 (United States); Whei-May Lee, Grace [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei (China)

2009-03-15

In this study, the impact factors of temperature, relative humidity (RH), air exchange rate, and volatile organic compound (VOC) properties on the VOC (toluene, n-butyl acetate, ethylbenzene, and m,p-xylene) specific emission rates (SERs) and concentrations from wooden flooring were investigated by chamber test for 8 days. The tested wood in this study is not common solid wood, but composite wood made of combined wood fibers. The experiments were conducted in a stainless-steel environmental test chamber coated with Teflon. The experimental results within 8 days of testing showed that, when the temperature increased from 15 to 30 C, the VOC SERs and concentrations increased 1.5-129 times. When the RH increased from 50% to 80%, the VOC concentrations and SERs increased 1-32 times. When the air change rate increased from 1 to 2 h{sup -1}, the VOC concentrations decreased 9-40%, while the VOC SERs increased 6-98%. The relations between the boiling points of the VOCs and each of the normalized VOC SERs and concentrations were linear with negative slopes. The relations between the vapor pressures of the VOCs and each of the normalized VOC SERs and concentrations were linear with positive slopes. At 15 C, RH50%, the relations between the diffusivities of VOCs and each of the normalized VOC equilibrium SERs and concentrations were linear with a positive slope. (author)

Benzene in blood as a biomarker of low level occupational exposure

Energy Technology Data Exchange (ETDEWEB)

Brugnone, F.; Perbellini, L.; Romeo, L.; Cerpelloni, M.; Bianchin, M.; Tonello, A. [Institute of Occupational Medicine, University of Verona, Policlinico Borgo Roma, 37134 Verona (Italy)

1999-09-01

The occupational airborne exposure to benzene of 150 workers employed in petrol stations and a refinery plant was assessed using personal sampling pumps. All workers provided blood samples after the end of work and on the following morning before resuming work. Benzene concentrations in the blood of 243 non-occupationally-exposed subjects were also measured. The median occupational benzene exposure for all 150 workers studied was 80 {mu}g/m{sup 3}. Overall median blood benzene of all workers was 251 ng/l at the end of the shift, and 174 ng/l the following morning. The benzene concentrations measured in blood collected the following morning proved to be significantly lower than those measured at the end of the shift. Median blood benzene for the 243 'normal' subjects was 128 ng/l, which was significantly lower than that measured in the workers before a new work shift. The median blood benzene concentration was significantly higher in smokers than in non-smokers, both in the general population (210 ng/l vs. 110 ng/l) and in the exposed workers at the end of the shift (476 ng/l vs. 132 ng/l) and the following morning (360 ng/l vs. 99 ng/l). End-of-shift blood benzene correlated significantly with environmental exposure; this correlation was better in the 83 non-smokers than in the 67 smokers. In non-smokers with the median benzene occupational exposure of 50 {mu}g/m{sup 3}, no difference was found in blood benzene concentration in exposed and non-exposed subjects.

Biological monitoring of benzene exposure for process operators during ordinary activity in the upstream petroleum industry.

Science.gov (United States)

Bråtveit, Magne; Kirkeleit, Jorunn; Hollund, Bjørg Eli; Moen, Bente E

2007-07-01

This study characterized the exposure of crude oil process operators to benzene and related aromatics during ordinary activity and investigated whether the operators take up benzene at this level of exposure. We performed the study on a fixed, integrated oil and gas production facility on Norway's continental shelf. The study population included 12 operators and 9 referents. We measured personal exposure to benzene, toluene, ethylbenzene and xylene during three consecutive 12-h work shifts using organic vapour passive dosimeter badges. We sampled blood and urine before departure to the production facility (pre-shift), immediately after the work shift on Day 13 of the work period (post-shift) and immediately before the following work shift (pre-next shift). We also measured the exposure to hydrocarbons during short-term tasks by active sampling using Tenax tubes. The arithmetic mean exposure over the 3 days was 0.042 ppm for benzene (range ethylbenzene and 0.03 ppm for xylene. Full-shift personal exposure was significantly higher when the process operators performed flotation work during the shift versus other tasks. Work in the flotation area was associated with short-term (6-15 min) arithmetic mean exposure to benzene of 1.06 ppm (range 0.09-2.33 ppm). The concentrations of benzene in blood and urine did not differ between operators and referents at any time point. When we adjusted for current smoking in regression analysis, benzene exposure was significantly associated with the post-shift concentration of benzene in blood (P = 0.01) and urine (P = 0.03), respectively. Although these operators perform tasks with relatively high short-term exposure to benzene, the full-shift mean exposure is low during ordinary activity. Some evidence indicates benzene uptake within this range of exposure.

40 CFR 80.1275 - How are early benzene credits generated?

Science.gov (United States)

2010-07-01

...), per § 80.1280(a). Bavg,y = Average benzene concentration of gasoline produced at the refinery during averaging period y (volume percent benzene), per § 80.1238. Ve,y = Total volume of gasoline produced at the... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading...

Evidence that humans metabolize benzene via two pathways.

NARCIS (Netherlands)

Rappaport, S.M.; Kim, S.; Lan, Q.; Vermeulen, R.C.H.; Waidyanatha, S.; Zhang, L.; Li, G.; Yin, S.; Hayes, R.B.; Rothman, N.; Smith, M.T.

2009-01-01

BACKGROUND: Recent evidence has shown that humans metabolize benzene more efficiently at environmental air concentrations than at concentrations > 1 ppm. This led us to speculate that an unidentified metabolic pathway was mainly responsible for benzene metabolism at ambient levels. OBJECTIVE: We

Building materials. VOC emissions, diffusion behaviour and implications from their use.

Science.gov (United States)

Katsoyiannis, Athanasios; Leva, Paolo; Barrero-Moreno, Josefa; Kotzias, Dimitrios

2012-10-01

Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m(-3), accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h). Copyright © 2012 Elsevier Ltd. All rights reserved.

Emissions of volatile organic compounds (VOCs) from cooking and their speciation: A case study for Shanghai with implications for China.

Science.gov (United States)

Wang, Hongli; Xiang, Zhiyuan; Wang, Lina; Jing, Shengao; Lou, Shengrong; Tao, Shikang; Liu, Jing; Yu, Mingzhou; Li, Li; Lin, Li; Chen, Ying; Wiedensohler, Alfred; Chen, Changhong

2018-04-15

Cooking emission is one of sources for ambient volatile organic compounds (VOCs), which is deleterious to air quality, climate and human health. These emissions are especially of great interest in large cities of East and Southeast Asia. We conducted a case study in which VOC emissions from kitchen extraction stacks have been sampled in total 57 times in the Megacity Shanghai. To obtain representative data, we sampled VOC emissions from kitchens, including restaurants of seven common cuisine types, canteens, and family kitchens. VOC species profiles and their chemical reactivities have been determined. The results showed that 51.26%±23.87% of alkane and 24.33±11.69% of oxygenated VOCs (O-VOCs) dominate the VOC cooking emissions. Yet, the VOCs with the largest ozone formation potential (OFP) and secondary organic aerosol potential (SOAP) were from the alkene and aromatic categories, accounting for 6.8-97.0% and 73.8-98.0%, respectively. Barbequing has the most potential of harming people's heath due to its significant higher emissions of acetaldehyde, hexanal, and acrolein. Methodologies for calculating VOC emission factors (EF) for restaurants that take into account VOCs emitted per person (EF person ), per kitchen stove (EF kitchen stove ) and per hour (EF hour ) are developed and discussed. Methodologies for deriving VOC emission inventories (S) from restaurants are further defined and discussed based on two categories: cuisine types (S type ) and restaurant scales (S scale ). The range of S type and S scale are 4124.33-7818.04t/year and 1355.11-2402.21t/year, respectively. We also found that S type and S scale for 100,000 people are 17.07-32.36t/year and 5.61-9.95t/year, respectively. Based on Environmental Kuznets Curve, the annual total amount of VOCs emissions from catering industry in different provinces in China was estimated, which was 5680.53t/year, 6122.43t/year, and 66,244.59t/year for Shangdong and Guangdong provinces and whole China, respectively

Metagenomic and proteomic analyses to elucidate the mechanism of anaerobic benzene degradation

Energy Technology Data Exchange (ETDEWEB)

Abu Laban, Nidal [Helmholtz (Germany)

2011-07-01

This paper presents the mechanism of anaerobic benzene degradation using metagenomic and proteomic analyses. The objective of the study is to find out the microbes and biochemistry involved in benzene degradation. Hypotheses are proposed for the initial activation mechanism of benzene under anaerobic conditions. Two methods for degradation, molecular characterization and identification of benzene-degrading enzymes, are described. The physiological and molecular characteristics of iron-reducing enrichment culture are given and the process is detailed. Metagenome analysis of iron-reducing culture is presented using a pie chart. From the metagenome analysis of benzene-degrading culture, putative mobile element genes were identified in the aromatic-degrading configurations. Metaproteomic analysis of iron-reducing cultures and the anaerobic benzene degradation pathway are also elucidated. From the study, it can be concluded that gram-positive bacteria are involved in benzene degradation under iron-reducing conditions and that the catalysis mechanism of putative anaerobic benzene carboxylase needs further investigation.

Belowground communication: impacts of volatile organic compounds (VOCs) from soil fungi on other soil-inhabiting organisms.

Science.gov (United States)

Werner, Stephanie; Polle, Andrea; Brinkmann, Nicole

2016-10-01

We reviewed the impact of fungal volatile organic compounds (VOCs) on soil-inhabiting organisms and their physiological and molecular consequences for their targets. Because fungi can only move by growth to distinct directions, a main mechanism to protect themselves from enemies or to manipulate their surroundings is the secretion of exudates or VOCs. The importance of VOCs in this regard has been significantly underestimated. VOCs not only can be means of communication, but also signals that are able to specifically manipulate the recipient. VOCs can reprogram root architecture of symbiotic partner plants or increase plant growth leading to enlarged colonization surfaces. VOCs are also able to enhance plant resistance against pathogens by activating phytohormone-dependent signaling pathways. In some cases, they were phytotoxic. Because the response was specific to distinct species, fungal VOCs may contribute to regulate the competition of plant communities. Additionally, VOCs are used by the producing fungus to attack rivaling fungi or bacteria, thereby protecting the emitter or its nutrient sources. In addition, animals, like springtails, nematodes, and earthworms, which are important components of the soil food web, respond to fungal VOCs. Some VOCs are effective repellents for nematodes and, therefore, have applications as biocontrol agents. In conclusion, this review shows that fungal VOCs have a huge impact on soil fauna and flora, but the underlying mechanisms, how VOCs are perceived by the recipients, how they manipulate their targets and the resulting ecological consequences of VOCs in inter-kingdom signaling is only partly understood. These knowledge gaps are left to be filled by future studies.

Variability of indoor and outdoor VOC measurements: An analysis using variance components

International Nuclear Information System (INIS)

Jia, Chunrong; Batterman, Stuart A.; Relyea, George E.

2012-01-01

This study examines concentrations of volatile organic compounds (VOCs) measured inside and outside of 162 residences in southeast Michigan, U.S.A. Nested analyses apportioned four sources of variation: city, residence, season, and measurement uncertainty. Indoor measurements were dominated by seasonal and residence effects, accounting for 50 and 31%, respectively, of the total variance. Contributions from measurement uncertainty (<20%) and city effects (<10%) were small. For outdoor measurements, season, city and measurement variation accounted for 43, 29 and 27% of variance, respectively, while residence location had negligible impact (<2%). These results show that, to obtain representative estimates of indoor concentrations, measurements in multiple seasons are required. In contrast, outdoor VOC concentrations can use multi-seasonal measurements at centralized locations. Error models showed that uncertainties at low concentrations might obscure effects of other factors. Variance component analyses can be used to interpret existing measurements, design effective exposure studies, and determine whether the instrumentation and protocols are satisfactory. - Highlights: ► The variability of VOC measurements was partitioned using nested analysis. ► Indoor VOCs were primarily controlled by seasonal and residence effects. ► Outdoor VOC levels were homogeneous within neighborhoods. ► Measurement uncertainty was high for many outdoor VOCs. ► Variance component analysis is useful for designing effective sampling programs. - Indoor VOC concentrations were primarily controlled by seasonal and residence effects; and outdoor concentrations were homogeneous within neighborhoods. Variance component analysis is a useful tool for designing effective sampling programs.

Technology projects for characterization--monitoring of volatile organic compounds (VOCs)

Energy Technology Data Exchange (ETDEWEB)

Junk, G.A.; Haas, W.J. Jr.

1992-07-01

One hundred thirty technology project titles related to the characterization of volatile organic compounds (VOCs) at an arid site are listed alphabetically by first contact person in a master compilation that includes phone numbers, addresses, keywords, and short descriptions. Separate tables are presented for 62 field-demonstrated, 36 laboratory-demonstrated, and 35 developing technology projects. The technology projects in each of these three categories are also prioritized in separate summary tables. Additional tables are presented for a number of other categorizations of the technology projects: In Situ; Fiberoptic; Mass Spectrometer; Optical Spectroscopy; Raman or SERS; Ion Mobility or Acoustic; Associated; and Commercial. Four lists of contact person names are provided so details concerning the projects that deal with sampling, and VOCs in gases, waters, and soils (sediments) can be obtained. Finally, seven wide-ranging conclusions based on observations and experiences during this work are presented.

Technology projects for characterization--monitoring of volatile organic compounds (VOCs)

International Nuclear Information System (INIS)

Junk, G.A.; Haas, W.J. Jr.

1992-07-01

One hundred thirty technology project titles related to the characterization of volatile organic compounds (VOCs) at an arid site are listed alphabetically by first contact person in a master compilation that includes phone numbers, addresses, keywords, and short descriptions. Separate tables are presented for 62 field-demonstrated, 36 laboratory-demonstrated, and 35 developing technology projects. The technology projects in each of these three categories are also prioritized in separate summary tables. Additional tables are presented for a number of other categorizations of the technology projects: In Situ; Fiberoptic; Mass Spectrometer; Optical Spectroscopy; Raman or SERS; Ion Mobility or Acoustic; Associated; and Commercial. Four lists of contact person names are provided so details concerning the projects that deal with sampling, and VOCs in gases, waters, and soils (sediments) can be obtained. Finally, seven wide-ranging conclusions based on observations and experiences during this work are presented

Selection of Sustainable Technology for VOC Abatement in an Industry: An Integrated AHP-QFD Approach

Science.gov (United States)

Gupta, Alok Kumar; Modi, Bharat A.

2018-04-01

Volatile organic compounds (VOCs) are universally present in global atmospheric pollutants. These VOCs are responsible for photo chemical reaction in atmosphere leading to serious harmful effects on human health and environment. VOCs are produced from both natural and man-made sources and may have good commercial value if it can be utilized as alternate fuel. As per data from US EPA, 15% of total VOC emissions are generated from surface coating industry but VOC concentration and exhaust air volume varies to a great extent and is dependent on processes used by industry. Various technologies are available for abatement of VOCs. Physical, Chemical and Biological technologies are available to remove VOCs by either recovery or destruction with many advantages and limitations. With growing environmental awareness and considering the resource limitations of medium and small scale industries, requirement of a tool for selecting appropriate techno economically viable solution for removal of VOCs from industrial process exhaust is envisaged. The aim of the present study is to provide management a tool to determine the overall effect of implementation of VOC abatement technology on business performance and VOC emissions. The primary purpose of this work is to outline a methodology to rate various VOC abatement technologies with respect to the constraint of meeting current and foreseeable future regulatory requirements, operational flexibility and Over All Economics Parameters considering conservation of energy. In this paper an integrated approach has been proposed to select most appropriate abatement technology strategically. Analytical hierarchy process and Quality function deployment have been integrated for Techno-commercial evaluation. A case study on selection of VOC abatement technology for a leading aluminium foil surface coating, lamination and printing facility using this methodology is presented in this study.

Benzene bioremediation using cow dung microflora in two phase partitioning bioreactor

Energy Technology Data Exchange (ETDEWEB)

Singh, Dipty [Environmental Biotechnology Laboratory, Department of Life Sciences, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai-400 098 (India); Fulekar, M.H., E-mail: mhfulekar@yahoo.com [Environmental Biotechnology Laboratory, Department of Life Sciences, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai-400 098 (India)

2010-03-15

Bioremediation of benzene has been carried out using cow dung microflora in a bioreactor. The bioremediation of benzene under the influence of cow dung microflora was found to be 100% and 67.5%, at initial concentrations of 100 mg/l and 250 mg/l within 72 h and 168 h respectively; where as at higher concentration (500 mg/l), benzene was found to be inhibitory. Hence the two phase partitioning bioreactor (TPPB) has been designed and developed to carryout biodegradation at higher concentration. In TPPB 5000 mg/l benzene was biodegraded up to 50.17% over a period of 168 h. Further the Pseudomonas putida MHF 7109 was isolated from cow dung microflora as potential benzene degrader and its ability to degrade benzene at various concentrations was evaluated. The data indicates 100%, 81% and 65% degradation at the concentrations of 50 mg/l, 100 mg/l, 250 mg/l within the time period of 24 h, 96 h and 168 h respectively. The GC-MS data also shows the presence of catechol and 2-hydroxymuconic semialdehyde, which confirms the established pathway of benzene biodegradation. The present research proves the potential of cow dung microflora as a source of biomass for benzene biodegradation in TPPB.

Content and Formation Cause of VOCs in Medical Waste Non-incineration Treatment Project

Science.gov (United States)

Dengchao, Jin; Hongjun, Teng; Zhenbo, Bao; Yang, Li

2018-02-01

When medical waste is treated by non-incineration technology, volatile organic compounds in the waste will be volatile out and form odor pollution. This paper studied VOCs productions in medical waste steam treatment project, microwave treatment project and chemical dinifection project. Sampling and analysis were carried out on the waste gas from treatment equipment and the gas in treatment workshop. The contents of nine VOCs were determined. It was found that the VOCs content in the exhaust gas at the outlet of steam treatment unit was much higher than that of microwave and chemical treatment unit, while the content of VOCs in the chemical treatment workshop was higher than that in the steam and microwave treatment workshop. The formation causes of VOCs were also analyzed and discussed in this paper.

688 AMBIENT VOLATILE ORGANIC COMPOUNDS (VOCS ...

African Journals Online (AJOL)

Osondu

using Gas Chromatography (GC) fitted with Flame Ionization Detector (FID). ... and Industrial emission were identified as sources of VOCs in the studied .... Wax, IIasamaja Market, Chesebrough way, ... A validation processes for diffusive.

Membrane Biotreatment of VOC-Laden Air

National Research Council Canada - National Science Library

Peretti, Stephen

2000-01-01

...%, depending primarily on air contact time. Octanol was used as the stripping fluid because of its low vapor pressure and water solubility, its high partitioning of VOCs from air, and its compatibility...

Role of Acidophilic Methanotrophs in Long Term Natural Attenuation of cVOCs in Low pH Aquifers

Science.gov (United States)

2017-06-15

grow well only in dilute , oligtrophic media (Kip et al., 2011; Dedysh et al., 2002). It is likely that these organisms or similar ones may exist in...Carbon tetrachloride Cu – Copper cVOCs – Chlorinated volatile organic compounds 1,1-DCA – 1,2-Dichloroethane 1,2-DCA – 1,2-Dichloroethane DCM...the biodegradation of chlorinated volatile organic compounds (cVOCs) in low pH groundwater aquifers. Our objectives included (1) determining whether

Building materials. VOC emissions, diffusion behaviour and implications from their use

International Nuclear Information System (INIS)

Katsoyiannis, Athanasios; Leva, Paolo; Barrero-Moreno, Josefa; Kotzias, Dimitrios

2012-01-01

Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m −3 , accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h). - Highlights: ► Neopentyl glycol is reported in emissions from building materials for the first time. ► Neopentyl glycol dominates the VOC emissions from cement-based building materials. ► A dual chamber was developed to control diffusion through building materials. ► Building materials facilitate diffusion of indoor air pollutants through their pores. - Neopentyl glycol was detected in high concentrations in emissions from building materials.

Methane from benzene in argon dielectric barrier discharge

International Nuclear Information System (INIS)

Das, Tomi Nath; Dey, G.R.

2013-01-01

Highlights: ► Efficient on-line conversion of benzene to methane at room temperature. ► Absence of other H-atom donor suggests new type of chemistry. ► For parent loss > 90%, methane yield was ∼40% of limit due to H-atom availability. ► Surface moisture contributed ·OH radical for trace phenolic products’ formation. ► This method may emerge as an exploitable tactic for pollutants’ usable alterations. -- Abstract: A first-time account of direct, on-line, instantaneous and efficient chemical conversion of gas phase benzene to methane in argon Dielectric Barrier Discharge (DBD) is presented. In the absence of another overt hydrogen-donating source, potency of analogous parents toward methane generation is found to follow the order: benzene > toluene > p-xylene. Simultaneous production of trace amounts of phenolic surface deposits suggest (a) prompt decomposition of the parent molecules, including a large fraction yielding atomic transients (H-atom), (b) continuous and appropriate recombination of such parts, and (c) trace moisture in parent contributing ·OH radicals and additional H-atoms, which suitably react with the unreacted fraction of the parent, and also other intermediates. Results highlight Ar DBD to be a simple and exploitable technology for transforming undesirable hazardous aromatics to usable/useful low molecular weight open-chain products following the principles of green chemistry and engineering

Biodegradation of benzene by halophilic and halotolerant bacteria under aerobic conditions.

Science.gov (United States)

Nicholson, Carla A; Fathepure, Babu Z

2004-02-01

A highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production facility in Oklahoma. The enrichment completely degraded benzene, toluene, ethylbenzene, and xylenes within 1 to 2 weeks. Also, [14C]benzene was converted to 14CO2, suggesting the culture's ability to mineralize benzene. Community structure analysis revealed that Marinobacter spp. were the dominant members of the enrichment.

FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests

Science.gov (United States)

Sukul, Pritam; Schubert, Jochen K.; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

2016-06-01

Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange.

Use of biofilters and suspended-growth reactors to treat VOC's

Energy Technology Data Exchange (ETDEWEB)

Neal, A.B.; Loehr, R.C.

2000-07-01

The greater limits placed on volatile organic compound (VOC) emissions by the Clean Air Act Amendments have stimulated evaluation of various VOC treatment methods. Two applicable gas phase treatment technologies are biofiltration and suspended growth reactors. Biofiltration removes contaminants from gas streams that are passed through a bed of biologically active solids. An aerobic suspended-growth reactor (SGR) removes VOCs by biologically treating contaminated air bubbled through an aqueous suspension of active microorganisms. This research compared the performance of a typical compost biofilter to a SGR for the removal of a common VOC (toluene) from gas streams. The objective was to evaluate the impact of mass loading on process performance. Major performance parameters investigated were (1) mass emitted and elimination capacity, (2) off-gas concentrations exiting each type of reactor for various mass loadings, and (3) removal efficiencies obtained by each type of reactor. The results indicated that SGRs can effectively treat gases containing VOCs. For mass loadings ranging from 5 to 30 mg/l-h, the biofilters and SGRs achieved similar VOC removals, in the range of 96--99.7%. Drying of the biofilter medium occurred a high mass loadings. In the SGRs, at mass loadings greater than 17 mg/l-h, process performance decreased when an unknown colored substance was present.

Study of benzene release from Savannah River in-tank precipitation process slurry simulant

International Nuclear Information System (INIS)

Rappe, K.G.; Gauglitz, P.A.

1998-08-01

At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry simulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every minute

Recent Development of Catalysts for Removal of Volatile Organic Compounds in Flue Gas by Combustion: A Review

Directory of Open Access Journals (Sweden)

Marco Tomatis

2016-01-01

Full Text Available Volatile organic compounds (VOCs emitted from anthropogenic sources pose direct and indirect hazards to both atmospheric environment and human health due to their contribution to the formation of photochemical smog and potential toxicity including carcinogenicity. Therefore, to abate VOCs emission, the catalytic oxidation process has been extensively studied in laboratories and widely applied in various industries. This report is mainly focused on the benzene, toluene, ethylbenzene, and xylene (BTEX with additional discussion about chlorinated VOCs. This review covers the recent developments in catalytic combustion of VOCs over noble metal catalysts, nonnoble metal catalysts, perovskite catalysts, spinel catalysts, and dual functional adsorbent-catalysts. In addition, the effects of supports, coke formation, and water effects have also been discussed. To develop efficient and cost-effective catalysts for VOCs removal, further research in catalytic oxidation might need to be carried out to strengthen the understanding of catalytic mechanisms involved.

Flux measurement of methanol, acetaldehyde and other oxygenated VOCs from crop harvesting using proton-transfer-reaction mass spectrometry and surface layer gradient method

International Nuclear Information System (INIS)

Lindinger, C.; Jordan, A.; Karl, T.; Guenther, A.; Tschiersch, J.; Ruckerbauer, F.; Paretzke, H.

2002-01-01

PTR-MS technique was used to measure fluxes of various VOC's including oxygenates using surface layer gradient method. The VOC concentrations and temperature were measured at heights of about 0.5 m and 3.9 m above ground at field site in St. Johann in Tirol during and after grass cutting (24th and 25th of May 2000) in order to calculate fluxes. The sensible heat flux was obtained by a sonic anemometer with turbulence data analyzer. The major crop in this part of Austria are perennial grasses used for livestock farming. We observed VOC emission fluxes including methanol and acetaldehyde as the major volatile, C 5 and C 6 leaf wound compounds with lesser amounts and traces of acetone and butanone. This composition of VOC's is very similar to that released from slashed pasture grass. At the same time, VOC fluxes were measured with PTR-MS and eddy covariance method. Comparing the flux data of methanol and acetaldehyde of both days have shown very similar results. (author)

Identification of volatile organic compounds (VOCs in different colour carrot (Daucus carota L. cultivars using static headspace/gas chromatography/mass spectrometry

Directory of Open Access Journals (Sweden)

Zehra Güler

2015-12-01

Full Text Available Volatile organic compounds (VOCs as well as sugar and acid contents affect carrot flavour. This study compared VOCs in 11 carrot cultivars. Gas chromatography/mass spectrometry using static headspace technique was applied to analyse the VOCs. The number of VOCs per sample ranged from 17 to 31. The primarily VOCs identified in raw carrots with the exception of “Yellow Stone” were terpenes, ranging from 65 to 95%. The monoterpenes with values ranging from 31 to 89% were higher than those (from 2 to 15% of sesquiterpenes. Monoterpene α-terpinolene (with ranging from 23 to 63% and (--α-pinene (26%, and alcohol ethanol (35% was the main VOC in extracts from the nine carrot cultivars, “Purple” and “Yellow Stone”, respectively. As a result, among 16 identified monoterpenes, 7 monoterpenes (--α-pinene, (--β-pinene, β-myrcene, d-limonene, γ-terpinene, α-terpinolene and p-cymene constituted more than 60% of total VOCs identified in carrots including “Atomic Red”, “Nantes”, “Cosmic Purple”, “Red Samurai”, “Eregli Black”, “White Satin”, “Parmex” and “Baby Carrot”. Thus, these cultivars may advise to carrot breeders due to the beneficial effects of terpenes, especially monoterpenes on health.

Tree Coring as an initial screening tool for typical pollutants in the subsurface

DEFF Research Database (Denmark)

Nielsen, Mette Algreen; Trapp, Stefan

2014-01-01

Previous guidelines report that tree coring is more or less useful for a variety of VOCs, such as BTEX, MTBE, trimethyl benzene, and chlorinated solvents (PCE, TCE, DCE, VC). This new guideline goes beyond the previous guidelines by including the use of a technique to screen for heavy metals, plus...

Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-03-08

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-09-06

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

Managing Exposure to Benzene and Total Petroleum Hydrocarbons at Two Oil Refineries 1977-2014.

Science.gov (United States)

Tuomi, Tapani; Veijalainen, Henna; Santonen, Tiina

2018-01-24

Air concentrations of and inhalation exposure to total petroleum hydrocarbons (TPH) and benzene was monitored separately at two oil refineries from 1977 to 2014. Prevention policies and control measures that may explain changes were surveyed. The aim was to evaluate how the application of of Occupational Health and Safety Assessment Series OHSAS 18001.04 principles as well as Environmental protection Agency EPA and European Oil Company Organisation for Environment, Health and Safety CONCAWE practices have influenced air concentrations. Benzene air concentrations declined in 11 of 17 units, six of which were associated with declining exposures. Benzene air concentrations declined across all units on average by 46%. This amounts to an average yearly decline of 1.7%. TPH air concentrations declined in 10 of 17 units, seven of which were associated with declining exposures. The average decline in TPH air concentrations was 49%, corresponding to 1.3% per year. As a result, average working day exposure in 10 of 17 units have declined significantly and today, benzene and TPH exposure in most units are well below 10% of the current Occupational Exposure Limit (OEL 8h :s). A decline in air concentrations have coincided with consistent implementation of control measures. Such measures include on-line monitoring of leaks; benzene recovery; floating container roofs; improved valves and seals; hermetic pumps; recovery of loading gases and instalment of torches in terminals; cutback in coke combustion; a new production line spanning directly from the dock to aromatics production; and recovery of loading gases in the doc. Other tools in exposure management include personal leak monitors, on-line measurements, monitoring campaigns, risk assessment, and availability and user training of protective equipment. However, improvements are still needed. Hydrocarbon or benzene air concentrations have not declined in 8 of 17 units, in some of which concentrations exceed 10% of the relevant

Mechanism of microsomal metabolism of benzene to phenol

Energy Technology Data Exchange (ETDEWEB)

Hinson, J.A.; Freeman, J.P.; Potter, D.W.; Mitchum, R.K.; Evans, F.E.

1985-05-01

The mechanism of microsomal hydroxylation of benzene to phenol has been studied by examining the microsomal metabolism of the specifically deuterated derivative 1,3,5-(/sub 2/H/sup 3/)benzene. Evidence for the formation of the following four products was obtained: 2,3,5-(/sub 2/H/sup 3/)phenol, 3,5-(/sub 2/H/sup 2/)phenol, 2,4,6-(/sub 2/H/sup 3/)phenol, and 2,4-(/sub 2/H/sup 2/)phenol. The presence of 2,3,5-(2H3)phenol and 2,4-(/sub 2/H/sup 2/)phenol shows that, in the microsomal metabolism of benzene to phenol, a NIH shift had occurred. A deuterium isotope effect (kH/kD) of approximately 4 was detected in both the meta- and para-deuterated phenols. This finding indicates that cyclohexadienone, formed either by isomerization of the epoxide or directly from the enzyme-substrate complex, is a major intermediate in the metabolism of benzene to phenol.

A comparative study of fungal and bacterial biofiltration treating a VOC mixture

International Nuclear Information System (INIS)

Estrada, José M.; Hernández, Sergio; Muñoz, Raúl; Revah, Sergio

2013-01-01

Highlights: ► Bacterial biofilter showed better EC and ΔP than fungal biofilter. ► The preferential biodegradation order was: propanal > hexanol > MIBK > toluene. ► Propanal partially inhibited the biodegradation of the rest of VOCs. ► The two-stage biofilter showed a higher stability than the individual units. -- Abstract: Bacterial biofilters usually exhibit a high microbial diversity and robustness, while fungal biofilters have been claimed to better withstand low moisture contents and pH values, and to be more efficient coping with hydrophobic volatile organic compounds (VOCs). However, there are only few systematic evaluations of both biofiltration technologies. The present study compared fungal and bacterial biofiltration for the treatment of a VOC mixture (propanal, methyl isobutyl ketone-MIBK, toluene and hexanol) under the same operating conditions. Overall, fungal biofiltration supported lower elimination capacities than its bacterial counterpart (27.7 ± 8.9 vs 40.2 ± 5.4 g C m −3 reactor h −1 ), which exhibited a final pressure drop 60% higher than that of the bacterial biofilter due to mycelial growth. The VOC mineralization ratio was also higher in the bacterial bed (≈63% vs ≈43%). However, the substrate biodegradation preference order was similar for both biofilters (propanal > hexanol > MIBK > toluene) with propanal partially inhibiting the consumption of the rest of the VOCs. Both systems supported an excellent robustness versus 24 h VOC starvation episodes. The implementation of a fungal/bacterial coupled system did not significantly improve the VOC removal performance compared to the individual biofilter performances

A comparative study of fungal and bacterial biofiltration treating a VOC mixture

Energy Technology Data Exchange (ETDEWEB)

Estrada, José M. [Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios 40, Col. Miguel Hidalgo, Delegación Álvaro Obregón (Mexico); Departamento de Ingeniería Química y Tecnología del Medio Ambiente – Universidad de Valladolid, Valladolid (Spain); Hernández, Sergio [Departmento de Procesos e Hidráulica – Universidad Autónoma Metropolitana – Iztapalapa Mexico D.F. Mexico (Mexico); Muñoz, Raúl [Departamento de Ingeniería Química y Tecnología del Medio Ambiente – Universidad de Valladolid, Valladolid (Spain); Revah, Sergio, E-mail: srevah@xanum.uam.mx [Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios 40, Col. Miguel Hidalgo, Delegación Álvaro Obregón (Mexico)

2013-04-15

Highlights: ► Bacterial biofilter showed better EC and ΔP than fungal biofilter. ► The preferential biodegradation order was: propanal > hexanol > MIBK > toluene. ► Propanal partially inhibited the biodegradation of the rest of VOCs. ► The two-stage biofilter showed a higher stability than the individual units. -- Abstract: Bacterial biofilters usually exhibit a high microbial diversity and robustness, while fungal biofilters have been claimed to better withstand low moisture contents and pH values, and to be more efficient coping with hydrophobic volatile organic compounds (VOCs). However, there are only few systematic evaluations of both biofiltration technologies. The present study compared fungal and bacterial biofiltration for the treatment of a VOC mixture (propanal, methyl isobutyl ketone-MIBK, toluene and hexanol) under the same operating conditions. Overall, fungal biofiltration supported lower elimination capacities than its bacterial counterpart (27.7 ± 8.9 vs 40.2 ± 5.4 g C m{sup −3} reactor h{sup −1}), which exhibited a final pressure drop 60% higher than that of the bacterial biofilter due to mycelial growth. The VOC mineralization ratio was also higher in the bacterial bed (≈63% vs ≈43%). However, the substrate biodegradation preference order was similar for both biofilters (propanal > hexanol > MIBK > toluene) with propanal partially inhibiting the consumption of the rest of the VOCs. Both systems supported an excellent robustness versus 24 h VOC starvation episodes. The implementation of a fungal/bacterial coupled system did not significantly improve the VOC removal performance compared to the individual biofilter performances.

Non-thermal plasmas for non-catalytic and catalytic VOC abatement

International Nuclear Information System (INIS)

Vandenbroucke, Arne M.; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

2011-01-01

Highlights: → We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. → The underlying mechanisms of plasma-catalysis for VOC abatement are discussed. → Critical process parameters that determine the influent are discussed and compared. - Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma-catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma-catalytic processes. In both parts (plasma-alone systems and plasma-catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.

Smartphone-based sensing system using ZnO and graphene modified electrodes for VOCs detection.

Science.gov (United States)

Liu, Lei; Zhang, Diming; Zhang, Qian; Chen, Xing; Xu, Gang; Lu, Yanli; Liu, Qingjun

2017-07-15

Volatile organic compounds (VOCs) detection is in high demand for clinic treatment, environment monitoring, and food quality control. Especially, VOCs from human exhaled breath can serve as significant biomarkers of some diseases, such as lung cancer and diabetes. In this study, a smartphone-based sensing system was developed for real-time VOCs monitoring using alternative current (AC) impedance measurement. The interdigital electrodes modified with zinc oxide (ZnO), graphene, and nitrocellulose were used as sensors to produce impedance responses to VOCs. The responses could be detected by a hand-held device, sent out to a smartphone by Bluetooth, and reported with concentration on an android program of the smartphone. The smartphone-based system was demonstrated to detect acetone at concentrations as low as 1.56ppm, while AC impedance spectroscopy was used to distinguish acetone from other VOCs. Finally, measurements of the exhalations from human being were carried out to obtain the concentration of acetone in exhaled breath before and after exercise. The results proved that the smartphone-based system could be applied on the detection of VOCs in real settings for healthcare diagnosis. Thus, the smartphone-based system for VOCs detection provided a convenient, portable and efficient approach to monitor VOCs in exhaled breath and possibly allowed for early diagnosis of some diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

Science.gov (United States)

Mao, Feng; Ong, Say Kee; Gaunt, James A

2015-09-01

Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

Assessment of subsurface VOCs using a chemical microsensor array

International Nuclear Information System (INIS)

Batterman, S.A.; Zellers, E.T.

1993-06-01

This report describes the results of laboratory investigations of several performance parameters relevant to surface-acoustic-wave (SAW) chemical sensor arrays for the measurement of volatile organic compounds (VOCs) in contaminated soil and groundwater. The small size, low cost, sensitivity and selectivity of such instruments promise improvements in the quality and quantity of data used to guide site assessment and restoration efforts. In this investigation, calibrations were performed for 15 different coated SAW sensors. Each sensor was exposed to six VOCs selected to represent three chemical classes of contaminants that are commonly found at waste sites (i.e., aliphatic, aromatic and chlorinated hydrocarbons). A new pattern recognition method was developed for determining which coated sensors would maximize the selectivity and accuracy of quantitation for a given set of vapor contaminants. Using this method, an optimal subwet of four coated sensors was selected for testing in a prototype microsensor instrument. Additional laboratory experiments were performed with this optimized array to assess the limits of detection and linear response ranges for the representative vapors, as well as the additivity of responses to vapors in binary mixtures, temperature and humidity effects, aging effects, and other performance parameters related to the application of this technology to soil and groundwater VOC monitoring. Results demonstrate that SAW microsensor arrays can identify and quantify specific VOCs at concentrations in the μg/L to mg/L range when present alone or in simple (e.g., binary) mixtures. SAW sensor technology offers a potentially effective alternative to existing field instrumentation for headspace analysis, soil vapor monitoring, and vacuum extraction process monitoring of VOCs in subsurface media

Increasing competitiveness of wine producers in strategic alliances VOC

Directory of Open Access Journals (Sweden)

Martin Prokeš

2012-01-01

Full Text Available The paper describes the main reasons for the formation of new regional association of wineries, based on a different origin for wines in the wine region of Moravia in the southeast part of the Czech Republic. This research aim is to create a plan for new development of such strategic alliances on the basis of results of localization factors. There coefficient of localization is used for identification of cluster. Results are compared with already operating on associations for the appellation in Austria DAC. They were traced changes in consumer preferences in the Czech wine market. Consumers are placing more emphasis on the selection of wine on its descent from a particular area, growing community and the individual grower. This paper specifically introduces new associations for appellation system VOC. This alliance is described in the context of the establishment, operation, development and expansion, respectively the possibility of involvement of additional organizations suppliers and research institutions. The application of the results of research was a plan for the establishment of new alliance VOC Modré Hory, where are associated 30 wine producers of wine in 5 villages around the center Velké Pavlovice. Based on the experience of newly emerging VOC system of appellations was setting up a plan of formation association with the proposed methodological approach. Open cooperation between associations VOC appellation and other entities involving suppliers, customers, research institutions and universities has the possibility of creating an institutionalized wine cluster. The plan to create a wine cluster was proposed to establish cooperation between the newly emerging associations of VOC at three sub-regions of South Moravia, in order to achieve competitive advantage.

Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate.

Science.gov (United States)

Manoukian, A; Buiron, D; Temime-Roussel, B; Wortham, H; Quivet, E

2016-04-01

This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values.

An analysis of violations of Osha's (1987) occupational exposure to benzene standard.

Science.gov (United States)

Williams, Pamela R D

2014-01-01

The Occupational Safety and Health Administration (OSHA), which was formed by the Occupational Safety and Health Act of 1970 (OSH Act), establishes enforceable health and safety standards in the workplace and issues violations and penalties for non-compliance with these standards. The purpose of the current study was to evaluate the number and type of violations of the OSHA (1987) Occupational Exposure to Benzene Standard. Violations of the OSHA Hazard Communication Standard (HCS), particularly those that may pertain to specific provisions of the benzene standard, were also assessed. All analyses were based on OSHA inspection data that have been collected since the early 1970s and that are publicly available from the U.S. Department of Labor enforcement website. Analysis of these data shows that fewer than a thousand OSHA violations of the benzene standard have been issued over the last 25+ years. The results for benzene are in contrast to those for some other toxic and hazardous substances that are regulated by OSHA, such as blood-borne pathogens, lead, and asbestos, for which there have been issued tens of thousands of OSHA violations. The number of benzene standard violations also varies by time period, standard provision, industry sector, and other factors. In particular, the greatest number of benzene standard violations occurred during the late 1980s to early/mid 1990s, soon after the 1987 final benzene rule was promulgated. The majority of benzene standard violations also pertain to noncompliance with specific provisions and subprovisions of the standard dealing with initial exposure monitoring requirements, the communication of hazards to employees, and medical surveillance programs. Only a small fraction of HCS violations are attributed, at least in part, to potential benzene hazards in the workplace. In addition, most benzene standard violations are associated with specific industries within the manufacturing sector where benzene or benzene

Benzene adsorption and hydrogenation on Pd-Ru alloy by pulse chromatography

International Nuclear Information System (INIS)

Dobrokhotov, V.G.; Pavlova, L.F.; Gryaznov, V.M.

1983-01-01

Pulse chromatography has been applied to investigate benzene adsorption and hydrogenation on the Walls of a capillary of the Pd-6% Ru alloy at different hydrogen contents in the alloy and various methods of hydrogen supply: as a mixture with benzene vapors or by diffusion through the walls of the capillary. It is stated that reversible adsorption of benzene vapors on the Pd-6% Ru alloy at 303 K under the conditions of the β-phase existence in the alloy-hydrogen system does not change whereas in the region of the α-phase existence it slightly increases with a growth of hydrogen pressure. Strongly adsorbed benzene occupies approximately 7% of the surface. Only strongly adsorbed benzene is hydrogenated on the α-phase of the alloy-hydrogen system. Hydrogen supply to the hydrogenation zone by diffusion throUgh the alloy results in supersaturation of the surface active in the reaction of benzene hydrogenation with a chemisorbed hydrogen form

Biomass burning contribution to ambient volatile organic compounds (VOCs) in the Chengdu-Chongqing Region (CCR), China

Science.gov (United States)

Li, Lingyu; Chen, Yuan; Zeng, Limin; Shao, Min; Xie, Shaodong; Chen, Wentai; Lu, Sihua; Wu, Yusheng; Cao, Wei

2014-12-01

Ambient volatile organic compounds (VOCs) were measured intensively using an online gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) at Ziyang in the Chengdu-Chongqing Region (CCR) from 6 December 2012 to 4 January 2013. Alkanes contributed the most (59%) to mixing ratios of measured non-methane hydrocarbons (NMHCs), while aromatics contributed the least (7%). Methanol was the most abundant oxygenated VOC (OVOC), contributing 42% to the total amount of OVOCs. Significantly elevated VOC levels occurred during three pollution events, but the chemical composition of VOCs did not differ between polluted and clean days. The OH loss rates of VOCs were calculated to estimate their chemical reactivity. Alkenes played a predominant role in VOC reactivity, among which ethylene and propene were the largest contributors; the contributions of formaldehyde and acetaldehyde were also considerable. Biomass burning had a significant influence on ambient VOCs during our study. We chose acetonitrile as a tracer and used enhancement ratio to estimate the contribution of biomass burning to ambient VOCs. Biomass burning contributed 9.4%-36.8% to the mixing ratios of selected VOC species, and contributed most (>30% each) to aromatics, formaldehyde, and acetaldehyde.

Peer Review Comments on the IRIS Assessment of Benzene

Science.gov (United States)

Attachment to IRIS file for benzene, January 19, 2000, RESPONSE TO THE PEER REVIEW COMMENTS, II. Extrapolation of the Benzene Inhalation Unit Risk Estimate to the Oral Route of Exposure (EPA/NCEA-W-0517, July 1999)

Source apportionment of VOCs and the contribution to photochemical ozone formation during summer in the typical industrial area in the Yangtze River Delta, China

Science.gov (United States)

Shao, Ping; An, Junlin; Xin, Jinyuan; Wu, Fangkun; Wang, Junxiu; Ji, Dongsheng; Wang, Yuesi

2016-07-01

Volatile organic compounds (VOCs) were continuously observated in a northern suburb of Nanjing, a typical industrial area in the Yangtze River Delta, in a summer observation period from 15th May to 31st August 2013. The average concentration of total VOCs was (34.40 ± 25.20) ppbv, including alkanes (14.98 ± 12.72) ppbv, alkenes (7.35 ± 5.93) ppbv, aromatics (9.06 ± 6.64) ppbv and alkynes (3.02 ± 2.01) ppbv, respectively. Source apportionment via Positive Matrix Factorization was conducted, and six major sources of VOCs were identified. The industry-related sources, including industrial emissions and industrial solvent usage, occupied the highest proportion, accounting for about 51.26% of the VOCs. Vehicular emissions occupied the second highest proportion, accounting for about 34.08%. The rest accounted for about 14.66%, including vegetation emission and liquefied petroleum gas/natural gas usage. Contributions of VOCs to photochemical O3 formation were evaluated by the application of a detailed chemical mechanism model (NCAR MM). Alkenes were the dominant contributors to the O3 photochemical production, followed by aromatics and alkanes. Alkynes had a very small impact on photochemical O3 formation. Based on the outcomes of the source apportionment, a sensitivity analysis of relative O3 reduction efficiency (RORE), under different source removal regimes such as using the reduction of VOCs from 10% to 100% as input, was conducted. The RORE was the highest (~ 20%-40%) when the VOCs from solvent-related sources decreased by 40%. The highest RORE values for vegetation emissions, industrial emissions, vehicle exhaust, and LPG/NG usage were presented in the scenarios of 50%, 80%, 40% and 40%, respectively.

STABILITY OF HEMOGLOBIN AND ALBUMIN ADDUCTS OF BENZENE OXIDE AND 1,4-BENZOQUINONE AFTER ADMINISTRATION OF BENZENE TO F344 RATS

Science.gov (United States)

The stability of cysteinyl adducts of benzene oxide (BO) and mono-S-substituted cysteinyl adducts of 1,4-benzoquinone (1,4-BQ) was investigated in both hemoglobin (Hb) and albumin (Alb) following administration of a single oral dose of 400 mg [U-14C/13C6]benzene/kg body weight ...

Establishment of a Methanogenic Benzene-Degrading Culture and its Implication in Bioremediation

Science.gov (United States)

Qiao, W.; Luo, F.; Bawa, N.; Guo, S.; Ye, S.; Edwards, E.

2017-12-01

Benzene is a known human carcinogen and it is a common pollutant in groundwater, mainly resulting from petrochemical industry. Anaerobic degradation of benzene has significant advantages over aerobic processes for in situ bioremediation. In this study, new methanogenic and sulfate-reducing benzene degrading cultures have been enriched. Microbial community composition was characterized with two other previously established benzene-degrading cultures, and their potential use in bioaugmentation is investigated. In this study, a lab microcosm study was conducted anaerobically with contaminated soil and groundwater from a former chemical plant. Benzene degradation was observed in the presence of co-contaminants and electron donor. Through repetitive amendment of benzene, two enrichment cultures have been developed under sulfate and methanogenic conditions. Results from DNA amplicon sequencing and qPCR analysis revealed that an organism similar to previously described benzene-degrading Deltaproteobacterium has been enriched. The microbial community of this culture was compared with other two methanogenic benzene-degrading enrichment cultures that were derived from an oil refinery and a decommissioned gasoline station, and have been maintained for decades. Deltaproteobacterium ORM2-like microbes were dominate in all enrichment cultures, which brought to light benzene-degrading microbes, ORM2 were enriched under different geological conditions distributed around the world. The relative abundance of methanogens was much lower compared to previously established cultures, although substantial amount of methane was produced. The peripheral organisms also vary. To investigate effectiveness of using ORM2-dominant enrichment cultures in bioremediation, microcosm studies were set up using contaminated materials, and a ORM2-dominating methanogenic benzene-degrading culture was used for bioaugmentation. Results revealed that benzene degradation was speeded up under methanogenic or

Cultivating microbial dark matter in benzene-degrading methanogenic consortia.

Science.gov (United States)

Luo, Fei; Devine, Cheryl E; Edwards, Elizabeth A

2016-09-01

The microbes responsible for anaerobic benzene biodegradation remain poorly characterized. In this study, we identified and quantified microbial populations in a series of 16 distinct methanogenic, benzene-degrading enrichment cultures using a combination of traditional 16S rRNA clone libraries (four cultures), pyrotag 16S rRNA amplicon sequencing (11 cultures), metagenome sequencing (1 culture) and quantitative polymerase chain reaction (qPCR; 12 cultures). An operational taxonomic unit (OTU) from the Deltaproteobacteria designated ORM2 that is only 84% to 86% similar to Syntrophus or Desulfobacterium spp. was consistently identified in all enrichment cultures, and typically comprised more than half of the bacterial sequences. In addition to ORM2, a sequence belonging to Parcubacteria (candidate division OD1) identified from the metagenome data was the only other OTU common to all the cultures surveyed. Culture transfers (1% and 0.1%) were made in the presence and absence of benzene, and the abundance of ORM2, OD1 and other OTUs was tracked over 415 days using qPCR. ORM2 sequence abundance increased only when benzene was present, while the abundance of OD1 and other OTUs increased even in the absence of benzene. Deltaproteobacterium ORM2 is unequivocally the benzene-metabolizing population. This study also hints at laboratory cultivation conditions for a member of the widely distributed yet uncultivated Parcubacteria (OD1). © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

VOCs Air Pollutant Cleaning with Polyacrylonitrile/Fly Ash Nanocomposite Electrospun Nanofibrous Membranes

Science.gov (United States)

Cong Ge, Jun; Wang, Zi Jian; Kim, Min Soo; Choi, Nag Jung

2018-01-01

Volatile organic compounds (VOCs) as an environmental pollution, which have many kinds of chemical structures, and many of them are very toxic. Therefore, controlling and reducing the presence of VOCs has become a hot topic among researchers for many years. In this study, the VOCs adsorption capacity of polyacrylonitrile/fly ash (PAN/FA) nanocomposite electrospun nanofibrous membranes were investigated. The results indicated that the PAN with different contents of FA powder (20%, 40%, 60%, 80%, and 100% compared with PAN by weight) could be spun well by electrospinning. The diameter of the fiber was very fine and its arrangement was irregular. The PAN nanofibrous membrane containing 60 wt% FA powder had the highest VOCs absorption capacity compared with other nanofibrous membranes due to its large specific surface area.

Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations

International Nuclear Information System (INIS)

Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

2004-12-01

This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

Implementation of VOC source reduction practices in a manufactured house and in school classrooms

International Nuclear Information System (INIS)

Hodgson, A.T.; Apte, M.G.; Shendell, D.G.; Beal, D.; McIlvaine, J.E.R.

2002-01-01

Detailed studies of a new manufactured house and four new industrialized relocatable school classrooms were conducted to determine the emission sources of formaldehyde and other VOCs and to identify and implement source reduction practices. Procedures were developed to generate VOC emission factors that allowed reasonably accurate predictions of indoor air VOC concentrations. Based on the identified sources of formaldehyde and other aldehydes, practices were developed to reduce the concentrations of these compounds in new house construction. An alternate ceiling panel reduced formaldehyde concentrations in the classrooms. Overall, the classrooms had relatively low VOC concentrations

Theoretical study of simultaneous water and VOCs adsorption and desorption in a silica gel rotor

DEFF Research Database (Denmark)

Zhang, G.; Zhang, Y.F.; Fang, Lei

2008-01-01

One-dimensional partial differential equations were used to model the simultaneous water and VOC (Volatile Organic Compound) adsorption and desorption in a silica gel rotor which was recommended for indoor air cleaning. The interaction among VOCs and moisture in the adsorption and desorption...... process was neglected in the model as the concentrations of VOC pollutants in typical indoor environment were much lower than that of moisture and the adsorbed VOCs occupied only a minor portion of adsorption capacity of the rotor. Consequently VOC transfer was coupled with heat and moisture transfer only...... by the temperatures of the rotor and the air stream. The VOC transfer equations were solved by discretizing them into explicit up-wind finite differential equations. The model was validated with experimental data. The calculated results suggested that the regeneration time designed for dehumidification may...

Crystal structures of 4-meth-oxy-N-(4-methyl-phenyl)benzene-sulfonamide and N-(4-fluoro-phenyl)-4-meth-oxy-benzene-sulfonamide.

Science.gov (United States)

Rodrigues, Vinola Z; Preema, C P; Naveen, S; Lokanath, N K; Suchetan, P A

2015-11-01

Crystal structures of two N-(ar-yl)aryl-sulfonamides, namely, 4-meth-oxy-N-(4-methyl-phen-yl)benzene-sulfonamide, C14H15NO3S, (I), and N-(4-fluoro-phen-yl)-4-meth-oxy-benzene-sulfonamide, C13H12FNO3S, (II), were determined and analyzed. In (I), the benzene-sulfonamide ring is disordered over two orientations, in a 0.516 (7):0.484 (7) ratio, which are inclined to each other at 28.0 (1)°. In (I), the major component of the sulfonyl benzene ring and the aniline ring form a dihedral angle of 63.36 (19)°, while in (II), the planes of the two benzene rings form a dihedral angle of 44.26 (13)°. In the crystal structure of (I), N-H⋯O hydrogen bonds form infinite C(4) chains extended in [010], and inter-molecular C-H⋯πar-yl inter-actions link these chains into layers parallel to the ab plane. The crystal structure of (II) features N-H⋯O hydrogen bonds forming infinite one dimensional C(4) chains along [001]. Further, a pair of C-H⋯O inter-molecular inter-actions consolidate the crystal packing of (II) into a three-dimensional supra-molecular architecture.

Ambient measurements of aromatic and oxidized VOCs by PTR-MS and GC-MS: intercomparison between four instruments in a boreal forest in Finland

Science.gov (United States)

Kajos, M. K.; Rantala, P.; Hill, M.; Hellén, H.; Aalto, J.; Patokoski, J.; Taipale, R.; Hoerger, C. C.; Reimann, S.; Ruuskanen, T. M.; Rinne, J.; Petäjä, T.

2015-10-01

Proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography mass spectrometry GC-MS) are commonly used methods for automated in situ measurements of various volatile organic compounds (VOCs) in the atmosphere. In order to investigate the reliability of such measurements, we operated four automated analyzers using their normal field measurement protocol side by side at a boreal forest site. We measured methanol, acetaldehyde, acetone, benzene and toluene by two PTR-MS and two GC-MS instruments. The measurements were conducted in southern Finland between 13 April and 14 May 2012. This paper presents correlations and biases between the concentrations measured using the four instruments. A very good correlation was found for benzene and acetone measurements between all instruments (the mean R value was 0.88 for both compounds), while for acetaldehyde and toluene the correlation was weaker (with a mean R value of 0.50 and 0.62, respectively). For some compounds, notably for methanol, there were considerable systematic differences in the mixing ratios measured by the different instruments, despite the very good correlation between the instruments (mean R = 0.90). The systematic difference manifests as a difference in the linear regression slope between measurements conducted between instruments, rather than as an offset. This mismatch indicates that the systematic uncertainty in the sensitivity of a given instrument can lead to an uncertainty of 50-100 % in the methanol emissions measured by commonly used methods.

Occurrence of Indoor VOCs in Nursery School - Case Study

Science.gov (United States)

Juhasova Senitkova, Ingrid

2017-10-01

Children’s exposure to air pollutants is an important public health challenge. Particular attention should be paid to preschools because younger children are more vulnerable to air pollution than higher grade children and spend more time indoors. The concentrations of volatile organic compounds (VOCs) as well as carbon dioxide (CO2) concentrations in younger and older children’s classrooms during the winter season were studied. An electronic nose based on gas chromatography was used for the analysis of individual VOCs and a photoionization detector with a UV lamp was used for the determination of total volatile organic compounds (TVOC) concentration. Continuous measurements of CO2 concentrations both inside classrooms and outside each building were performed using automatic portable monitors. Improving ventilation, decreasing the occupancy per room and completing cleaning activities following occupancy periods can contribute to alleviating high CO2 and VOCs occurrence levels.

Determination of volatile organic compounds pollution sources in malaysian drinking water using multivariate analysis.

Science.gov (United States)

Soh, Shiau-Chian; Abdullah, Md Pauzi

2007-01-01

A field investigation was conducted at all water treatment plants throughout 11 states and Federal Territory in Peninsular Malaysia. The sampling points in this study include treatment plant operation, service reservoir outlet and auxiliary outlet point at the water pipelines. Analysis was performed by solid phase micro-extraction technique with a 100 microm polydimethylsiloxane fibre using gas chromatography with mass spectrometry detection to analyse 54 volatile organic compounds (VOCs) of different chemical families in drinking water. The concentration of VOCs ranged from undetectable to 230.2 microg/l. Among all of the VOCs species, chloroform has the highest concentration and was detected in all drinking water samples. Average concentrations of total trihalomethanes (THMs) were almost similar among all states which were in the range of 28.4--33.0 microg/l. Apart from THMs, other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene and 1,2-dichloro - benzene. Principal component analysis (PCA) with the aid of varimax rotation, and parallel factor analysis (PARAFAC) method were used to statistically verify the correlation between VOCs and the source of pollution. The multivariate analysis pointed out that the maintenance of auxiliary pipelines in the distribution systems is vital as it can become significant point source pollution to Malaysian drinking water.

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions.

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-09-27

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs.

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-01-01

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs. PMID:28904262

Environmental and biological applications of microplasmas

International Nuclear Information System (INIS)

Becker, K; Koutsospyros, A; Yin, S-M; Christodoulatos, C; Abramzon, N; Joaquin, J C; Brelles-Marino, G

2005-01-01

Stable glow-type discharge plasmas at elevated pressures can be generated and maintained easily when the plasma is spatially confined to cavities with critical dimensions below 1 mm ('microplasmas'). We studied the properties of several atmospheric-pressure microplasmas and their use in the remediation of volatile organic compounds (VOCs) and biological decontamination. The VOCs studied include individual prototypcal aliphatic and aromatic compounds as well as mixtures such as BTEX (benzene, toluene, ethylbenzene and xylene). The biological systems under study included individual bacteria as well as bacterial biofilms, which are highly structured communities of bacteria that are very resistant to antibiotics, germicides, and other conventional forms of destruction

Extended Research on Detection of Deception Using Volatile Organic Compound (VOC) Emissions

Energy Technology Data Exchange (ETDEWEB)

Center for Human Reliability Studies

2006-06-01

A system that captures and analyzes volatile organic compound (VOC) emissions from skin surfaces may offer a viable alternative method to the polygraph instrument currently in use for detecting deception in U.S. government settings. Like the involuntary autonomic central nervous system response data gathered during polygraph testing, VOC emissions from the skin may provide data that can be used to detect stress caused by deception. Detecting VOCs, then, may present a noninvasive, non-intrusive method for observing, recording, and quantifying evidence of stress or emotional change.

An experimental study on regulated and unregulated pollutants from a spark ignition car fuelled on liquefied petroleum gas and Gasoline

International Nuclear Information System (INIS)

Shah, A.N.; Yun-shan, G.E.; Jun-fang, W.; Jian-wei, T.; Gardezi, S.A.R.

2010-01-01

In the experimental study conducted on a spark ignition (SI) car running on a chassis dynamometer, fuelled on liquefied petroleum gas (LPG) and gasoline, carbon monoxide (CO) and total hydrocarbons (HC) decreased by 37.3% and 46.8%, respectively, while oxides of nitrogen (NOx) increased by 59.7% due to higher compression ratio with LPG, compared with gasoline. In case of LPG fuel, formaldehyde, acetaldehyde, propionaldehyde, 2-butanone, butyraldehyde, benzaldehyde and valeraldehyde decreased, leading to an over all decrease of about 35% and 26% in carbonyls and their ozone forming potential (OFP), respectively, compared with gasoline. Furthermore, benzene, toluene, ethyl benzene, xylene and styrene decreased, resulting in an overall decrease of 38.8% in volatile organic compounds (VOCs) and 39.2% in BTEX (benzene, toluene, ethyl benzene and xylene) species due to more complete combustion with LPG, compared with gasoline. Further, the OFP of VOCs with LPG was 6% lower than that with gasoline fuel. (author)

Impact of intentionally introduced sources on indoor VOC levels

Energy Technology Data Exchange (ETDEWEB)

Davis, C.S. [BOVAR Environmental, Downsview, Ontario (Canada); Otson, R. [Health Canada, Ottawa, Ontario (Canada). Environmental Health Centre

1997-12-31

The concentrations of 33 target volatile organic compounds (VOC) were measured in outdoor air and in indoor air before and after the introduction of dry-cleaned clothes, and consumer products into two suburban homes. Emissions from the household products (air fresheners, furniture polishes, mothballs, and dry-cleaned clothes), showering, and two paints were analyzed to obtain source profiles. There were measurable increases in the 24 h average concentrations for 10 compounds in one house and 8 compounds in the second house after introduction of the sources. A contribution by showering to indoor VOC was not evident although the impact of the other sources and outdoor air could be discerned, based on results for the major constituents of source emissions. Also, contributions by paints, applied three to six weeks prior to the monitoring, to indoor VOC concentrations were evident. The pattern of concentrations indicated that sink effects need to be considered in explaining the indoor concentrations that result when sources are introduced into homes. Quantitative estimates of the relative contributions of the sources to indoor VOC levels were not feasible through the use of chemical mass balance since the number of tracer species detected (up to 6) and that could be used for source apportionment was similar to the number of sources to be apportioned (up to 7).

Managing Exposure to Benzene and Total Petroleum Hydrocarbons at Two Oil Refineries 1977–2014

Science.gov (United States)

Tuomi, Tapani; Veijalainen, Henna; Santonen, Tiina

2018-01-01

Air concentrations of and inhalation exposure to total petroleum hydrocarbons (TPH) and benzene was monitored separately at two oil refineries from 1977 to 2014. Prevention policies and control measures that may explain changes were surveyed. The aim was to evaluate how the application of of Occupational Health and Safety Assessment Series OHSAS 18001.04 principles as well as Environmental protection Agency EPA and European Oil Company Organisation for Environment, Health and Safety CONCAWE practices have influenced air concentrations. Benzene air concentrations declined in 11 of 17 units, six of which were associated with declining exposures. Benzene air concentrations declined across all units on average by 46%. This amounts to an average yearly decline of 1.7%. TPH air concentrations declined in 10 of 17 units, seven of which were associated with declining exposures. The average decline in TPH air concentrations was 49%, corresponding to 1.3% per year. As a result, average working day exposure in 10 of 17 units have declined significantly and today, benzene and TPH exposure in most units are well below 10% of the current Occupational Exposure Limit (OEL8h:s). A decline in air concentrations have coincided with consistent implementation of control measures. Such measures include on-line monitoring of leaks; benzene recovery; floating container roofs; improved valves and seals; hermetic pumps; recovery of loading gases and instalment of torches in terminals; cutback in coke combustion; a new production line spanning directly from the dock to aromatics production; and recovery of loading gases in the doc. Other tools in exposure management include personal leak monitors, on-line measurements, monitoring campaigns, risk assessment, and availability and user training of protective equipment. However, improvements are still needed. Hydrocarbon or benzene air concentrations have not declined in 8 of 17 units, in some of which concentrations exceed 10% of the relevant

Seasonal variability and source apportionment of volatile organic compounds (VOCs in the Paris megacity (France

Directory of Open Access Journals (Sweden)

A. Baudic

2016-09-01

Full Text Available Within the framework of air quality studies at the megacity scale, highly time-resolved volatile organic compound (C2–C8 measurements were performed in downtown Paris (urban background sites from January to November 2010. This unique dataset included non-methane hydrocarbons (NMHCs and aromatic/oxygenated species (OVOCs measured by a GC-FID (gas chromatograph with a flame ionization detector and a PTR-MS (proton transfer reaction – mass spectrometer, respectively. This study presents the seasonal variability of atmospheric VOCs being monitored in the French megacity and their various associated emission sources. Clear seasonal and diurnal patterns differed from one VOC to another as the result of their different origins and the influence of environmental parameters (solar radiation, temperature. Source apportionment (SA was comprehensively conducted using a multivariate mathematical receptor modeling. The United States Environmental Protection Agency's positive matrix factorization tool (US EPA, PMF was used to apportion and quantify ambient VOC concentrations into six different sources. The modeled source profiles were identified from near-field observations (measurements from three distinct emission sources: inside a highway tunnel, at a fireplace and from a domestic gas flue, hence with a specific focus on road traffic, wood-burning activities and natural gas emissions and hydrocarbon profiles reported in the literature. The reconstructed VOC sources were cross validated using independent tracers such as inorganic gases (NO, NO2, CO, black carbon (BC and meteorological data (temperature. The largest contributors to the predicted VOC concentrations were traffic-related activities (including motor vehicle exhaust, 15 % of the total mass on the annual average, and evaporative sources, 10 %, with the remaining emissions from natural gas and background (23 %, solvent use (20 %, wood-burning (18 % and a biogenic source (15 %. An

Temporary vs. Permanent Sub-slab Ports: A Comparative ...

Science.gov (United States)

Vapor intrusion (VI) is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), from the subsurface to indoor air. The VI exposure pathway extends from the contaminant source, which can be impacted soil, non-aqueous phase liquid, or contaminated groundwater, to indoor air-exposure points. Therefore, contaminated matrices may include groundwater, soil, soil gas, and indoor air. VOC contaminants of concern typically include halogenated solvents such as trichloroethene, tetrachloroethene, and chloroform, as well as petroleum hydrocarbons, such as the aromatic VOCs benzene, toluene, and xylenes. Radon is a colorless radioactive gas that is released by radioactive decay of radionuclides in rock and soil that migrate into homes through VI in a similar fashion to VOCs. This project focused on the performance of permanent versus temporary sub-slab sampling ports for the determination of VI of halogenated VOCs and radon into an unoccupied house. VOC and radon concentrations measured simultaneously in soil gas using collocated temporary and permanent ports appeared to be independent of the type of port. The variability between collocated temporary and permanent ports was much less than the spatial variability between different locations within a single residential duplex. The agreement of the majority of VOC and radon concentrations, 0–36% relative percent difference, and 2–19% relative standard deviation respectively, of each sub-sl

Polyfunctional catalyst for processiing benzene fractions

Energy Technology Data Exchange (ETDEWEB)

G. Byakov; B.D. Zubitskii; B.G. Tryasunov; I.Ya. Petrov [Kuznetsk Basin State Technical University, Kemerovo (Russian Federation)

2009-05-15

A by-product of the coke industry is a raw benzene fraction benzene- 1 which may serve as for catalytic processes. The paper reports a study on the influence of the composition and temperatures on the activity and selectivity of NiO-V{sub 2}O{sub 6}-MoO{sub 3}/{gamma}-Al{sub 2}O{sub 3} catalysts and the corresponding binary and tertiary subsystems are studied by a pulse method in model reactions; the hydrodealkylating of toluene and the hydrodesulfurizing of thioprhene. The optimal catalyst composition is established. The new catalyst is compared with industrial catalysts.

In situ treatment of VOCs by recirculation technologies

International Nuclear Information System (INIS)

Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E.; Kearl, P.M.; Zutman, J.L.

1993-06-01

The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided

In situ treatment of VOCs by recirculation technologies

Energy Technology Data Exchange (ETDEWEB)

Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E. [Oak Ridge National Lab., TN (US); Kearl, P.M.; Zutman, J.L. [Oak Ridge National Lab., Grand Junction, CO (US)

1993-06-01

The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided.

Resolving uncertainty in the spatial relationships between passive benzene exposure and risk of non-Hodgkin lymphoma.

Science.gov (United States)

Switchenko, Jeffrey M; Bulka, Catherine; Ward, Kevin; Koff, Jean L; Bayakly, A Rana; Ryan, P Barry; Waller, Lance A; Flowers, Christopher R

2016-04-01

Benzene is a known occupational carcinogen associated with increased risk of hematologic cancers, but the relationships between quantity of passive benzene exposure through residential proximity to toxic release sites, duration of exposure, lag time from exposure to cancer development, and lymphoma risk remain unclear. We collected release data through the Environmental Protection Agency's Toxics Release Inventory (TRI) from 1989 to 2003, which included location of benzene release sites, years when release occurred, and amount of release. We also collected data on incident cases of non-Hodgkin lymphoma (NHL) from the Georgia Comprehensive Cancer Registry (GCCR) for the years 1999-2008. We constructed distance-decay surrogate exposure metrics and Poisson and negative binomial regression models of NHL incidence to quantify associations between passive exposure to benzene and NHL risk and examined the impact of amount, duration of exposure, and lag time on cancer development. Akaike's information criteria (AIC) were used to determine the scaling factors for benzene dispersion and exposure periods that best predicted NHL risk. Using a range of scaling factors and exposure periods, we found that increased levels of passive benzene exposure were associated with higher risk of NHL. The best fitting model, with a scaling factor of 4 kilometers (km) and exposure period of 1989-1993, showed that higher exposure levels were associated with increased NHL risk (Level 4 (1.1-160kilograms (kg)) vs. Level 1: risk ratio 1.56 [1.44-1.68], Level 5 (>160kg) vs. Level 1: 1.60 [1.48-1.74]). Higher levels of passive benzene exposure are associated with increased NHL risk across various lag periods. Additional epidemiological studies are needed to refine these models and better quantify the expected total passive benzene exposure in areas surrounding release sites. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Advances in chemical sensing technologies for VOCs in breath for security/threat assessment, illicit drug detection, and human trafficking activity.

Science.gov (United States)

Giannoukos, S; Agapiou, A; Taylor, S

2018-01-17

On-site chemical sensing of compounds associated with security and terrorist attacks is of worldwide interest. Other related bio-monitoring topics include identification of individuals posing a threat from illicit drugs, explosive manufacturing, as well as searching for victims of human trafficking and collapsed buildings. The current status of field analytical technologies is directed towards the detection and identification of vapours and volatile organic compounds (VOCs). Some VOCs are associated with exhaled breath, where research is moving from individual breath testing (volatilome) to cell breath (microbiome) and most recently to crowd breath metabolites (exposome). In this paper, an overview of field-deployable chemical screening technologies (both stand-alone and those with portable characteristics) is given with application to early detection and monitoring of human exposome in security operations. On-site systems employed in exhaled breath analysis, i.e. mass spectrometry (MS), optical spectroscopy and chemical sensors are reviewed. Categories of VOCs of interest include (a) VOCs in human breath associated with exposure to threat compounds, and (b) VOCs characteristic of, and associated with, human body odour (e.g. breath, sweat). The latter are relevant to human trafficking scenarios. New technological approaches in miniaturised detection and screening systems are also presented (e.g. non-scanning digital light processing linear ion trap MS (DLP-LIT-MS), nanoparticles, mid-infrared photo-acoustic spectroscopy and hyphenated technologies). Finally, the outlook for rapid and precise, real-time field detection of threat traces in exhaled breath is revealed and discussed.

Interim report: Study of benzene release from Savannah River in-tank precipitation process slurry simulant

International Nuclear Information System (INIS)

Rappe, K.G.; Gauglitz, P.A.

1997-09-01

At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form a 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses both flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry stimulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every 3 minutes. The following 75-mL samples were measured for release rates: KTPB slurry with 15,000 ppm freshly added benzene that was gently mixed with the slurry, KTPB slurry homogenized (energetically mixed) with 15,000 ppm and 5,000 ppm benzene, clear and filtered KTPB salt solution saturated with benzene (with and without a pure benzene layer on top of the solution), and a slurry sample from a large demonstration experiment (DEMO slurry) containing-benzene generated in situ

Source impacts by volatile organic compounds in an industrial city of southern Taiwan.

Science.gov (United States)

Liu, Pao-Wen Grace; Yao, Yung-Chen; Tsai, Jiun-Horng; Hsu, Yi-Chyun; Chang, Li-Peng; Chang, Ken-Hui

2008-07-15

This study investigates source impacts by airborne volatile organic compounds (VOC) at two sites designated for traffic and industry, in the largest industrial area Kaohsiung, southern Taiwan. The samples were collected at the two sites simultaneously during rush and non-rush hours in summer and autumn seasons. Same pattern of VOC groups were found at both sites: most abundant aromatics (78-95%) followed by alkanes (2-16%) and alkenes (0-6%). The BTEX concentration measured at the two sites ranged from 69 to 301 ppbC. Toluene, isopentane, ethylbenzene, and benzene were found to be the most abundant species. Speciation of VOCs was characterized with several skills including principal component factor analysis and BTEX characteristic ratios. Each of the resulted principal factors at the two sites explained over 80% of the VOCs data variance, and indicated that both of the sampling sites were influenced by both traffic and industrial sources with separately different levels. The remarkable patterns of the first two factors described not only the similarity but also the discrepancy at the two sampling sites, in terms of the source impacts. The high T/B ratios (7.56-14.25) observed at the industrial site implied the important impact from mobile emissions. The indicators, m,p-xylene/benzene and o-xylene/benzene, also confirmed the potential source of motor vehicles at both of the sampling sites. Air age assessment showed that more than half of the total observations located in the domain of fresh air. Low X/E ratios implied somewhat aged air mass transported to the sampling sites. The industrial site might not only encounter emissions from the industry sources, but also under unavoidable impact from the traffic sources.

Hybrid Photonic Cavity with Metal-Organic Framework Coatings for the Ultra-Sensitive Detection of Volatile Organic Compounds with High Immunity to Humidity

Science.gov (United States)

Tao, Jifang; Wang, Xuerui; Sun, Tao; Cai, Hong; Wang, Yuxiang; Lin, Tong; Fu, Dongliang; Ting, Lennon Lee Yao; Gu, Yuandong; Zhao, Dan

2017-01-01

Detection of volatile organic compounds (VOCs) at parts-per-billion (ppb) level is one of the most challenging tasks for miniature gas sensors because of the high requirement on sensitivity and the possible interference from moisture. Herein, for the first time, we present a novel platform based on a hybrid photonic cavity with metal-organic framework (MOF) coatings for VOCs detection. We have fabricated a compact gas sensor with detection limitation ranging from 29 to 99 ppb for various VOCs including styrene, toluene, benzene, propylene and methanol. Compared to the photonic cavity without coating, the MOF-coated solution exhibits a sensitivity enhancement factor up to 1000. The present results have demonstrated great potential of MOF-coated photonic resonators in miniaturized gas sensing applications.

VOCs and formaldehyde emissions from cleaning products and air fresheners

OpenAIRE

Solal , Cécilia; Rousselle , Christophe; Mandin , Corinne; Manel , Jacques; Maupetit , François

2008-01-01

International audience; Human indoor exposure to Volatile Organic Compounds (VOCs) may be associated with the use of household products. However little is known about their emissions and to what extent they contribute to indoor air pollution. The French Agency for Environmental and Occupational Health Safety (Afsset) conducted tests in order to characterize VOCs emissions from 32 consumer products: air fresheners, glass cleaners, furniture polishes, toilet products, carpet and floor cleaning ...

Investigations of VOCs in and around buildings close to service stations

Science.gov (United States)

Hicklin, William; Farrugia, Pierre S.; Sinagra, Emmanuel

2018-01-01

Gas service stations are one of the major sources of volatile organic compounds in urban environments. Their emissions are expected not only to affect the ambient air quality but also that in any nearby buildings. This is particularly the case in Malta where most service stations have been built within residential zones. For this reason, it is important to understand the dispersion of volatile organic compounds (VOCs) from service stations and their infiltration into nearby residences. Two models were considered; one to predict the dispersion of VOCs in the outdoor environment in the vicinity of the service station and another one to predict the filtration of the compounds indoors. The two models can be used in tandem to predict the concentration of indoor VOCs that originate from a service station in the vicinity. Outdoor and indoor concentrations of VOCs around a service station located in a street canyon were measured, and the results used to validate the models. Predictions made using the models were found to be in general agreement with the measured concentrations of the pollutants.

[Concentration and change of VOCs in summer and autumn in Tangshan].

Science.gov (United States)

Sun, Jie; Wang, Yue-si; Wu, Fang-kun; Qiu, Jun

2010-07-01

In order to study the potential impact of volatile organic compounds (VOCs) in summer and autumn on region ozone, ambient concentrations and changes of VOCs were analyzed at Tangshan from June to September 2007 and 2008, by using the method of two-step-concentration-gas spectrometry/mass (CCD-GC/MS). The average concentration in Tangshan was 163.5 x 10(-9) C. The major components were alkanes, aromatics, alkenes and halogen hydrocarbons which accounted for 45.9%, 29.9%, 5.9% and 18.9% respectively. The average concentration decreased 51.9% compare with 2007 (340.4 x 10(-9) C), confine gas stations is the main reason of the decline of alkyl, the large decline is aromatic hydrocarbons, 67%, which has the most potential impact of ozone formation, and dichlorobenzene in industrial emissions has increased. The concentrations of VOCs in Tangshan were lower 8% than that of Beijing during the same period in 2008. The changes of VOCs during 2008 Beijing Olympic show that in addition to traffic source industrial emissions is also an important source of atmospheric pollution.

Supplementary measurements for air monitoring under NOVANA - Benzene and PAH; Supplerende maalinger til luftovervaagning under NOVANA - benzen og PAH

Energy Technology Data Exchange (ETDEWEB)

Ellermann, T.; Klenoe Noejgaard, J.; Bossi, R.

2011-10-15

The report presents results from a project carried out for the Danish Environmental Protection Agency. The aim of the project was to carry out several measuring campaigns in order to be able to better assess the monitoring needs for PAH and benzene in relation to EU's air quality directives. The results show that the mean concentrations of benzene are almost at the same level in Denmark's four largest cities, and that the concentrations are both below the threshold value (5mug/m3) as well as below the lower assessment threshold (2mug/m3). The report presents a method for objectively estimation the benzene concentration based on measurements of CO. The method can be applied to fulfil the monitoring need for benzene in those zones where no measurements of benzene are made. Measurements of PAH, especially benzo(a)pyrene, have been made during 12 months in the period 2010-2011 in an area with many wood burning furnaces are used (the town Jyllinge). The concentrations of benzo(a)pyrene in Jyllinge is almost three times higher than in the street H.C. Andersens Boulevard in Copenhagen. The concentrations of benzo(a)pyrene in Jylllinge are 0,6 ng/m3, which corresponds to the upper assessment threshold (0,6 ng/m3) and is 40% below the measuring value (1 ng/m3). On this basis, there is a need for re-evaluating the monitoring of PAH in the sub-programme for air under NOVANA. Measurements of PM{sub 10} showed that the levels in the towns Jyllinge, Lille Valby/Risoe and at the H.C. Oersted Institute in Copenhagen are all at about 20-22 mug/m3. (LN)

Radiolysis of triphenylarsine in a mixture of benzene and cyclohexane. [. gamma. radiation

Energy Technology Data Exchange (ETDEWEB)

Nazir, S B; Rai, R S [Birla Inst. of Tech. and Science, Pilani (India). Dept. of Chemistry

1975-06-01

A number of degassed samples of triphenylarsine were irradiated by gamma radiation in a mixture of benzene and cyclohexane. The condensable products formed were pentane, hexane, benzene and cyclohexane in cyclohexane solution containing triphenylarsine and cyclohexane in benzene in presence of triphenylarsine. When the composition of the solvent was varried by stepwise addition of benzene from 5 to 50%, the main condensable radiolytic products observed by vapour phase chromatography were hexane, : hexane and cyclohexene. No pentane was observed when benzene was present in the mixture upto 15%. However, it was detected in the presence of 20-30% benzene mixture. When the amount of benzene was 35-50% in the mixture, two isomers of hexane and hexene were also detected. A mechanism has been worked out for the formation of these compounds and protection and sensitization mechanisms have been invoked to explain the yields per 100 ev. From the kinetic analysis, it has been found out that the rate of formation of cyclohexene is much faster than rates of different products formed during gamma radiolysis and from the analysis of experimental data, sponge type protection has been postulated in this radiolytic system.

Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

Energy Technology Data Exchange (ETDEWEB)

Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

2011-11-15

Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

International Nuclear Information System (INIS)

Cervantes, Francisco J.; Mancilla, Ana Rosa; Toro, E. Emilia Rios-del; Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia

2011-01-01

Highlights: → Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. → Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. → Several species from classes β-, δ- and γ-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq) L -1 , linked to the reduction of 619 ± 81 μEq L -1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

Canada-wide standard for benzene phase 1 : Progress report 2001

International Nuclear Information System (INIS)

2001-01-01

In June 2000, the Canadian Council of Ministers of the Environment (CCME) ratified the Canada-Wide Standard (CWS) for Benzene Phase 1. Benzene is classified as a carcinogen to humans and any level of exposure is generally considered to carry some probability of harmful effects. The Ministers committed to reducing national benzene emissions by 30 per cent between 1995 and 2000. This report presents the progress thus far and describes how the Alberta Government has focused on effecting emission reductions in the natural gas sector, dehydrators, petroleum refineries and in chemical manufacturing plants. Their initiatives led to a 66 per cent decrease in benzene emissions by 1999. In addition, overall emissions in the province were reduced by 50 per cent from industry and mobile sources. The measures initiated during Phase 1 will continue beyond the time frame, and Phase 2, not yet ratified, will call for a follow-through on those measures. Phase 2 recognizes best management practices and jurisdictional regulations that will minimize emissions. Specifically, Phase 2 calls for an additional reduction of 6 kilotonnes in benzene emissions for existing facilities by the end of 2010. The minimization of benzene emissions through the application of best available pollution prevention and control techniques is contained for new and expanding facilities. The implementation of the CWS comprises the follow-up of existing initiatives resulting from the application of Phase 1 and the promotion and application of best management practices for new and expanding facilities, the determination and tracking of ancillary emission reductions of benzene realized as a result of other CWS initiatives, and the monitoring and reporting of progress. 13 refs., 4 tabs., 3 figs

Exposure to Particle Matters and Hazardous Volatile Organic Compounds in Selected Hot Spring Hotels in Guangdong, China

Directory of Open Access Journals (Sweden)

Qiusheng He

2016-04-01

Full Text Available In Guangdong province, many hot springs were exploited and developed into popular places for tourist. In addition, hotels have been set up near hot spring sites to attract people, including local citizens, to spend their spare time inside these so-called “spring hotels”. In our study, indoor air quality was investigated in four hot spring hotels in Guangdong province, China. Measured indoor pollutants included CO2, CO, PM10, PM2.5 and Volatile Organic Compounds (VOCs. As the result show, high concentrations of carbon dioxide might be attributed to poor ventilation; and the variations of indoor PM10, PM2.5 concentrations were related to occupants’ activities. Alpha-pinene and toluene were the most common VOC species in the hot spring hotels other than monocyclic aromatic hydrocarbons like Benzene, Toluene, Ethylbenzene and Xylenes (BTEX, which were at medium levels among the reported indoor pollutants. High cancer risk of benzene in the newly decorated rooms should be seriously taken into consideration in the future. Indoor to Outdoor air concentration ratios (I/O for CO2 and VOCs were higher than 1, indicating their strong indoor sources. Negative correlations were found between indoor CO2 and all the other compounds, and VOCs were shown to be significantly correlated (p < 0.01 to each other, including aromatic hydrocarbons and mono-terpenes. For indoor and outdoor air compounds, correlation coefficients among all compounds did not show a significant correlation, which indicated that these pollutants had different sources. Principal components analysis by SPSS showed that indoor materials, inhabitants’ activities and respiration, cleaning products and outdoor sources were the main sources of indoor detected pollutants in hot spring hotels.

Dynamics of Rb{sup +}-benzene and Rb{sup +}-benzene-Ar {sub n} (n {<=} 3) clusters

Energy Technology Data Exchange (ETDEWEB)

Alberti, M. [Centre de Recerca en Quimica Teorica, Departament de Quimica Fisica, Parc Cientific, Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain)], E-mail: m.alberti@ub.edu; Aguilar, A. [Centre de Recerca en Quimica Teorica, Departament de Quimica Fisica, Parc Cientific, Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain); Lucas, J.M. [Centre de Recerca en Quimica Teorica, Departament de Quimica Fisica, Parc Cientific, Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain); Cappelletti, D. [Dipartimento di Ingegneria Civile ed Ambientale, Universita di Perugia, 06123 Perugia (Italy); Lagana, A. [Dipartimento di Chimica, Universita di Perugia, 06123 Perugia (Italy); Pirani, F. [Dipartimento di Chimica, Universita di Perugia, 06123 Perugia (Italy)

2006-09-29

The potential energy function of the Rb{sup +}-benzene cluster and of some of its Ar solvated variants is here modeled using a combination (pairwise sum) of ion(atom)-molecular bond and ion-molecular charges interaction contributions which provide, respectively, the non electrostatic and the electrostatic terms of the total non covalent intermolecular potential energy. In particular, such interaction contributions have been represented using, in addition to the ion(atom) polarizability, the bond polarizability tensor components and the charge distribution which account, respectively, for the polarizability and the quadrupolar moment of the benzene molecule. On the resulting potential energy surface, dynamical calculations have been carried out for the microcanonical ensemble by focusing on isomerization processes and on the effect of the mass of the cation.

Volatile Organic Compound (VOC Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up

Directory of Open Access Journals (Sweden)

Philippe Moulin

2011-03-01

Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

Evaluation of volatile organic compound (VOC) blank data and application of study reporting levels to groundwater data collected for the California GAMA Priority Basin Project, May 2004 through September 2010

Science.gov (United States)

Fram, Miranda S.; Olsen, Lisa D.; Belitz, Kenneth

2012-01-01

Volatile organic compounds (VOCs) were analyzed in quality-control samples collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. From May 2004 through September 2010, a total of 2,026 groundwater samples, 211 field blanks, and 109 source-solution blanks were collected and analyzed for concentrations of 85 VOCs. Results from analyses of these field and source-solution blanks and of 2,411 laboratory instrument blanks during the same time period were used to assess the quality of data for the 2,026 groundwater samples. Eighteen VOCs were detected in field blanks or source-solution blanks: acetone, benzene, bromodichloromethane, 2-butanone, carbon disulfide, chloroform, 1,1-dichloroethene, dichloromethane, ethylbenzene, tetrachloroethene, styrene, tetrahydrofuran, toluene, trichloroethene, trichlorofluoromethane, 1,2,4-trimethylbenzene, m- and p-xylenes, and o-xylene. The objective of the evaluation of the VOC-blank data was to determine if study reporting levels (SRLs) were needed for any of the VOCs detected in blanks to ensure the quality of the data from groundwater samples. An SRL is equivalent to a raised reporting level that is used in place of the reporting level used by the analyzing laboratory [long‑term method detection level (LT-MDL) or laboratory reporting level (LRL)] to reduce the probability of reporting false-positive detections. Evaluation of VOC-blank data was done in three stages: (1) identification of a set of representative quality‑control field blanks (QCFBs) to be used for calculation of SRLs and identification of VOCs amenable to the SRL approach, (2) evaluation of potential sources of contamination to blanks and groundwater samples by VOCs detected in field blanks, and (3) selection of appropriate SRLs from among four potential SRLs for VOCs detected in field blanks and application of those SRLs to the groundwater data. An important conclusion from this study is that to ensure the

Analysis of air toxics, criteria pollutants and meteorological monitoring data in Valdez, Alaska

International Nuclear Information System (INIS)

Stopenhagen, K.W.; Kester, R.A.; Caniparoli, D.G.; Gravely, R.J.

1991-01-01

An ambient monitoring network began operation in Valdez, Alaska in August 1990. The twelve month study for the Alyeska Pipeline Service Company will gather data for regulatory compliance, risk assessment dispersion modeling. The network consists of seven sites. Four sites measure selected species of VOCs by laboratory grade gas chromatographs. The GCS yield hourly concentrations, special plumbing, valving and computer software enable unattended and automated operation. Chromatography is performed by flame ionization detector. Pollutants measured are benzene, ethyl-benzene, toluene and xylenes. Criteria pollutants are measured at four sites; one of which is for permit compliance. VOC and Criteria data presented will show site-by-site concentration comparisons, relate values to ambient standards, and applicability of previous modeling results. A discussion of the use of lab-grade gas chromatographs in the field for automated continuous sampling will be included. Meteorological data discussion will analyze circulation patterns within the fjord for patterns such as cross fjord transport and terrain induced flow regimes

Pressure Dependence of Molar Volume near the Melting Point in Benzene

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.

Volatile organic compound emissions from Larrea tridentata (creosotebush

Directory of Open Access Journals (Sweden)

A. Guenther

2010-12-01

Full Text Available We present results from the CREosote ATmosphere Interactions through Volatile Emissions (CREATIVE 2009 field study in southern Arizona aimed at quantifying emission rates of VOCs from creosotebush (Larrea tridentata during the summer 2009 monsoon season. This species was chosen because of its vast distribution in North and South American deserts and because its resins have been reported to contain a rich set of volatile organic compounds (VOC. While a variety of ecosystems have been investigated for VOC emissions, deserts remain essentially unstudied, partially because of their low biomass densities and water limitations. However, during the North American monsoon, a pronounced increase in rainfall from an extremely dry June (80 mm occurs over large areas of the Sonoran desert in the southwestern United States and northwestern Mexico. We observed a strong diurnal pattern of branch emissions and ambient concentrations of an extensive suite of VOCs with maxima in early afternoon. These include VOCs typically observed in forest sites (oxygenated VOCs and volatile isoprenoids as well as a large number of other compounds, some of which have not been previously described from any plant including 1-chloro-2-methoxy-benzene and isobutyronitrile. Although generally considered to be derived from anthropogenic sources, we observed emissions of aromatic compounds including benzene, and a broad range of phenolics. Dimethyl sulfide emissions from creosotebush were higher than reported from any previously studied plant suggesting that terrestrial ecosystems should be reconsidered as an important source of this climatically important gas. We also present direct, primary emission measurements of isoprene and its apparent oxidation products methyl vinyl ketone, methacrolein, and 3-methyl furan (the later three compounds are typically assumed to form from secondary reactions within the atmosphere, as well as a group of compounds considered to be fatty acid

[Estimation of VOC emission from forests in China based on the volume of tree species].

Science.gov (United States)

Zhang, Gang-feng; Xie, Shao-dong

2009-10-15

Applying the volume data of dominant trees from statistics on the national forest resources, volatile organic compounds (VOC) emissions of each main tree species in China were estimated based on the light-temperature model put forward by Guenther. China's VOC emission inventory for forest was established, and the space-time and age-class distributions of VOC emission were analyzed. The results show that the total VOC emissions from forests in China are 8565.76 Gg, of which isoprene is 5689.38 Gg (66.42%), monoterpenes is 1343.95 Gg (15.69%), and other VOC is 1532.43 Gg (17.89%). VOC emissions have significant species variation. Quercus is the main species responsible for emission, contributing 45.22% of the total, followed by Picea and Pinus massoniana with 6.34% and 5.22%, respectively. Southwest and Northeast China are the major emission regions. In specific, Yunnan, Sichuan, Heilongjiang, Jilin and Shaanxi are the top five provinces producing the most VOC emissions from forests, and their contributions to the total are 15.09%, 12.58%, 10.35%, 7.49% and 7.37%, respectively. Emissions from these five provinces occupy more than half (52.88%) of the national emissions. Besides, VOC emissions show remarkable seasonal variation. Emissions in summer are the largest, accounting for 56.66% of the annual. Forests of different ages have different emission contribution. Half-mature forests play a key role and contribute 38.84% of the total emission from forests.

VOCs-Mediated Location of Olive Fly Larvae by the Braconid Parasitoid Psyttalia concolor: A Multivariate Comparison among VOC Bouquets from Three Olive Cultivars

Directory of Open Access Journals (Sweden)

Giulia Giunti

2016-01-01

Full Text Available Herbivorous activity induces plant indirect defenses, as the emission of herbivorous-induced plant volatiles (HIPVs, which could be used by parasitoids for host location. Psyttalia concolor is a larval pupal endoparasitoid, attacking a number of tephritid flies including B. oleae. In this research, we investigated the olfactory cues routing host location behavior of P. concolor towards B. oleae larvae infesting three different olive cultivars. VOCs from infested and healthy fruits were identified using GC-MS analyses. In two-choice behavioral assays, P. concolor females preferred infested olive cues, which also evoked ovipositional probing by female wasps. GC-MS analysis showed qualitative and quantitative differences among volatiles emitted by infested and healthy olives. Volatile emissions were peculiar for each cultivar analyzed. Two putative HIPVs were detected in infested fruits, regardless of the cultivar, the monoterpene (E-β-ocimene, and the sesquiterpene (E-E-α-farnesene. Our study adds basic knowledge to the behavioral ecology of P. concolor. From an applied point of view, the field application of the above-mentioned VOCs may help to enhance effectiveness of biological control programs and parasitoid mass-rearing techniques.

Identification of genes specifically required for the anaerobic metabolism of benzene in Geobacter metallireducens

DEFF Research Database (Denmark)

Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar

2014-01-01

Although the biochemical pathways for the anaerobic degradation of many of the hydrocarbon constituents in petroleum reservoirs have been elucidated, the mechanisms for anaerobic activation of benzene, a very stable molecule, are not known. Previous studies have demonstrated that Geobacter...... metallireducens can anaerobically oxidize benzene to carbon dioxide with Fe(III) as the sole electron acceptor and that phenol is an intermediate in benzene oxidation. In an attempt to identify enzymes that might be involved in the conversion of benzene to phenol, whole-genome gene transcript abundance...... was compared in cells metabolizing benzene and cells metabolizing phenol. Eleven genes had significantly higher transcript abundance in benzene-metabolizing cells. Five of these genes had annotations suggesting that they did not encode proteins that could be involved in benzene metabolism and were not further...

VOC reactivity and its effect on ozone production during the HaChi summer campaign

Directory of Open Access Journals (Sweden)

L. Ran

2011-05-01

Full Text Available Measurements of ozone and its precursors conducted within the HaChi (Haze in China project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs and their effects on ozone photochemical production at a suburban site in the North China Plain (NCP. Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred on about two thirds of the observational days during the 5-week field campaign. This suggests continuous ozone exposure risks in this region in the summer. Average concentrations of nitrogen oxides (NO_x and VOCs are about 20 ppbv and 650 ppbC, respectively. On average, total VOC reactivity is dominated by anthropogenic VOCs. The contribution of biogenic VOCs to total ozone-forming potential, however, is also considerable in the daytime. Key species associated with ozone photochemical production are 2-butenes (18 %, isoprene (15 %, trimethylbenzenes (11 %, xylenes (8.5 %, 3-methylhexane (6 %, n-hexane (5 % and toluene (4.5 %. Formation of ozone is found to be NO_x-limited as indicated by measured VOCs/NO_x ratios and further confirmed by a sensitivity study using a photochemical box model NCAR_MM. The Model simulation suggests that ozone production is also sensitive to changes in VOC reactivity under the NO_x-limited regime, although this sensitivity depends strongly on how much NO_x is present.

Formation of a new benzene-ethane co-crystalline structure under cryogenic conditions.

Science.gov (United States)

Vu, Tuan Hoang; Cable, Morgan L; Choukroun, Mathieu; Hodyss, Robert; Beauchamp, Patricia

2014-06-12

We report the first experimental finding of a solid molecular complex between benzene and ethane, two small apolar hydrocarbons, at atmospheric pressure and cryogenic temperatures. Considerable amounts of ethane are found to be incorporated inside the benzene lattice upon the addition of liquid ethane onto solid benzene at 90-150 K, resulting in formation of a distinctive co-crystalline structure that can be detected via micro-Raman spectroscopy. Two new features characteristic of these co-crystals are observed in the Raman spectra at 2873 and 1455 cm(-1), which are red-shifted by 12 cm(-1) from the υ1 (a1g) and υ11 (eg) stretching modes of liquid ethane, respectively. Analysis of benzene and ethane vibrational bands combined with quantum mechanical modeling of isolated molecular dimers reveal an interaction between the aromatic ring of benzene and the hydrogen atoms of ethane in a C-H···π fashion. The most favored configuration for the benzene-ethane dimer is the monodentate-contact structure, with a calculated interaction energy of 9.33 kJ/mol and an equilibrium bonding distance of 2.66 Å. These parameters are comparable to those for a T-shaped co-crystalline complex between benzene and acetylene that has been previously reported in the literature. These results are relevant for understanding the hydrocarbon cycle of Titan, where benzene and similar organics may act as potential hydrocarbon reservoirs due to this incorporation mechanism.

Development of new VOC exposure metrics and their relationship to ''Sick Building Syndrome'' symptoms

Energy Technology Data Exchange (ETDEWEB)

Ten Brinke, JoAnn [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab., Berkeley, CA (United States)

1995-08-01

Volatile organic compounds (VOCs) are suspected to contribute significantly to ''Sick Building Syndrome'' (SBS), a complex of subchronic symptoms that occurs during and in general decreases away from occupancy of the building in question. A new approach takes into account individual VOC potencies, as well as the highly correlated nature of the complex VOC mixtures found indoors. The new VOC metrics are statistically significant predictors of symptom outcomes from the California Healthy Buildings Study data. Multivariate logistic regression analyses were used to test the hypothesis that a summary measure of the VOC mixture, other risk factors, and covariates for each worker will lead to better prediction of symptom outcome. VOC metrics based on animal irritancy measures and principal component analysis had the most influence in the prediction of eye, dermal, and nasal symptoms. After adjustment, a water-based paints and solvents source was found to be associated with dermal and eye irritation. The more typical VOC exposure metrics used in prior analyses were not useful in symptom prediction in the adjusted model (total VOC (TVOC), or sum of individually identified VOCs (ΣVOC_i)). Also not useful were three other VOC metrics that took into account potency, but did not adjust for the highly correlated nature of the data set, or the presence of VOCs that were not measured. High TVOC values (2--7 mg m^-3) due to the presence of liquid-process photocopiers observed in several study spaces significantly influenced symptoms. Analyses without the high TVOC values reduced, but did not eliminate the ability of the VOC exposure metric based on irritancy and principal component analysis to explain symptom outcome.

Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation.

Science.gov (United States)

Zheng, Yi-Wen; Chen, Bin; Ye, Pan; Feng, Ke; Wang, Wenguang; Meng, Qing-Yuan; Wu, Li-Zhu; Tung, Chen-Ho

2016-08-17

We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.

Disturbance response indicators of Impatiens walleriana exposed to benzene and chromium.

Science.gov (United States)

Campos, V; Lessa, S S; Ramos, R L; Shinzato, M C; Medeiros, T A M

2017-08-03

The purpose of this study was to evaluate the remediation potential and disturbance response indicators of Impatiens walleriana exposed to benzene and chromium. Numerous studies over the years have found abundant evidence of the carcinogenicity of benzene and chromium (VI) in humans. Benzene and chromium are two toxic industrial chemicals commonly found together at contaminated sites, and one of the most common management strategies employed in the recovery of sites contaminated by petroleum products and trace metals is in situ remediation. Given that increasing interest has focused on the use of plants as depollution agents, direct injection tests and benzene misting were performed on I. walleriana to evaluate the remediation potential of this species. I. walleriana accumulated hexavalent chromium, mainly in the root system (164.23 mg kg -1 ), to the detriment of the aerial part (39.72 mg kg -1 ), and presented visible damage only at the highest concentration (30 mg L -1 ). Unlike chromium (VI), chromium (III) was retained almost entirely by the soil, leaving it available for removal by phytotechnology. However, after the contamination stopped, I. walleriana responded positively to the detoxification process, recovering its stem stiffness and leaf color. I. walleriana showed visible changes such as leaf chlorosis during the ten days of benzene contamination. When benzene is absorbed by the roots, it is translocated to and accumulated in the plant's aerial part. This mechanism the plant uses ensures its tolerance to the organic compound, enabling the species to survive and reproduce after treatment with benzene. Although I. walleriana accumulates minor amounts of hexavalent chromium in the aerial part, this amount suffices to induce greater oxidative stress and to increase the amount of hydrogen peroxide when compared to that of benzene. It was therefore concluded that I. walleriana is a species that possesses desirable characteristics for phytotechnology.

Human risk assessment of benzene after a gasoline station fuel leak

Directory of Open Access Journals (Sweden)

Miriam dos Anjos Santos

2013-06-01

Full Text Available OBJECTIVE: To assess the health risk of exposure to benzene for a community affected by a fuel leak. METHODS: Data regarding the fuel leak accident with, which occurred in the Brasilia, Federal District, were obtained from the Fuel Distributor reports provided to the environmental authority. Information about the affected population (22 individuals was obtained from focal groups of eight individuals. Length of exposure and water benzene concentration were estimated through a groundwater flow model associated with a benzene propagation model. The risk assessment was conducted according to the Agency for Toxic Substances and Disease Registry methodology. RESULTS: A high risk perception related to the health consequences of the accident was evident in the affected community (22 individuals, probably due to the lack of assistance and a poor risk communication from government authorities and the polluting agent. The community had been exposed to unsafe levels of benzene (> 5 µg/L since December 2001, five months before they reported the leak. The mean benzene level in drinking water (72.2 µg/L was higher than that obtained by the Fuel Distributer using the Risk Based Corrective Action methodology (17.2 µg/L.The estimated benzene intake from the consumption of water and food reached a maximum of 0.0091 µg/kg bw/day (5 x 10-7 cancer risk per 106 individuals. The level of benzene in water vapor while showering reached 7.5 µg/m3 for children (1 per 104 cancer risk. Total cancer risk ranged from 110 to 200 per 106 individuals. CONCLUSIONS: The population affected by the fuel leak was exposed to benzene levels that might have represented a health risk. Local government authorities need to develop better strategies to respond rapidly to these types of accidents to protect the health of the affected population and the environment.

Characterization of void volume VOC concentration in vented TRU waste drums - an interim report

International Nuclear Information System (INIS)

Liekhus, K.J.

1994-09-01

A test program is underway at the Idaho National Engineering Laboratory to determine if the concentration of volatile organic compounds (VOCs) in the drum headspace is representative of the VOC concentration in the entire drum void space and to demonstrate that the VOC concentration in the void space of each layer of confinement can be estimated using a model incorporating diffusion and permeation transport principles and limited waste drum sampling data. An experimental test plan was developed requiring gas sampling of 66 transuranic (TRU) waste drums. This interim report summarizes the experimental measurements and model predictions of VOC concentration in the innermost layer of confinement from waste drums sampled and analyzed in FY 1994

Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

KAUST Repository

Zhang, Qian; Mi, Wenbo; Wang, Xiaocha; Wang, Xuhui

2015-01-01

We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom.

Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

KAUST Repository

Zhang, Qian

2015-05-27

We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom.

Benzene and its Isomers

Indian Academy of Sciences (India)

organic chemistry in particular is the period between 1825 when benzene was isolated and 1865 when its correct structure was proposed. Significant initial strides were made during these years in finding new organic reactions and searching for meth- ods to draw molecular structures. For an average chemist the molecular ...

An Analysis of Air Pollution Control Technologies for Shipyard Emitted Volatile Organic Compounds (VOCS)

National Research Council Canada - National Science Library

Snider, Thomas J

1993-01-01

...) emissions from industrial operations. One approach to VOC reduction is through air pollution control technology to remove the contaminants from the exhaust airstream of VOC generating processes...

Volatile organic compounds (VOCs) emission characteristics and control strategies for a petrochemical industrial area in middle Taiwan.

Science.gov (United States)

Yen, Chia-Hsien; Horng, Jao-Jia

2009-11-01

This study investigated VOC emissions from the largest petrochemical industrial district in Taiwan and recommended some control measures to reduce VOC emissions. In addition to the petrochemical industry, the district encompasses a chemical and fiber industry, a plastics industry and a harbor, which together produce more than 95% of the VOC emissions in the area. The sequence of VOC emission was as follows: components (e.g., valves, flanges, and pumps) (47%) > tanks (29%) > stacks (15%) > wastewater treatment facility (6%) > loading (2%) > flares (1%). Other plants producing high-density polyethylene (HDPE), styrene, ethylene glycol (EG), gas oil, and iso-nonyl-alchol (INA) were measured to determine the VOC leaching in the district. The VOC emissions of these 35 plants (90% of all plants) were less than 100 tons/year. About 74% of the tanks were fixed-roof tanks that leached more VOCs than the other types of tanks. To reduce leaching, the components should be checked periodically, and companies should be required to follow the Taiwan EPA regulations. A VOC emission management system was developed in state implementation plans (SIPs) to inspect and reduce emissions in the industrial district.

Seasonal variations in VOC emission rates from gorse (Ulex europaeus)

Science.gov (United States)

Boissard, C.; Cao, X.-L.; Juan, C.-Y.; Hewitt, C. N.; Gallagher, M.

Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10-1300 μmol m-2 s-1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, trans-ocimene and γ-terpinene were also emitted, with α-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33-66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 μg C (g dwt)-1 h-1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 μg C (g dwt)-1 h-1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.

PARAMETRIC EVALUATION OF VOC CONVERSION VIA CATALYTIC INCINERATION

Directory of Open Access Journals (Sweden)

Kaskantzis Neto G.

1997-01-01

Full Text Available Abstract - A pilot-scale catalytic incineration system was used to investigate the effectiveness of catalytic incineration as a means of reducing volatile organic compound (VOC air pollutants. The objectives of the study were: 1 to investigate the effects of operating and design variables on the reduction efficiency of VOCs; and 2 to evaluate reduction efficiencies for specific compounds in different chemical classes. The study results verified that the following factors affect the catalyst performance: inlet temperature, space velocity, compound type, and compound inlet concentration. Tests showed that reduction efficiencies exceeding 98% were possible, given sufficiently high inlet gas temperatures for the following classes of compounds: alcohols, acetates, ketones, hydrocarbons, and aromatics

Assessment of Benzene Exposures in the Working Environment at Gasoline Stations

Directory of Open Access Journals (Sweden)

Sunisa Chaiklieng

2015-07-01

Full Text Available This study aimed to investigate benzene exposure in the working environment of workers at gasoline stations. Ambient air (n=20 and inhaled air samples (n=101 of benzene were collected in the city of Khon Kaen, Thailand and analyzed with gas chromatography (GC-FID. Data records were also kept of the amounts of various petroleum products sold. The results of inhaled air benzene indicated the range concentration from 0.03 ppb to 65.71 ppb and showed significant differences between concentrations of each zone (p<0.05. The highest mean concentration was found in suburban stations (35.55 ppb, followed by urban stations (18.19 ppb, and rural stations (2.52 ppb. The highest mean concentration of ambient air was found in urban stations (45.55 ppb. Regarding different job functions, the benzene concentration of fueling workers in the inhalation zone (27.29 ppb was significantly higher than that of cashiers (0.56 ppb. The amounts of petroleum products with high benzene content sold were relatively consistent with inhaled benzene concentration, indicated by the significant differences between suburban and rural zones (p<0.05. In conclusion, this study found the inhaled air benzene concentration ranged 0.03 to 65.71 ppb depending on locations and job functions of workers. Therefore, workers should be protected of adversely affected health from long-term exposure by training on safe working practice and awareness of the different risks associated with their job functions, locations of stations and daily amounts of petroleum products sold.

Field demonstration and transition of SCAPS direct push VOC in-situ sensing technologies

International Nuclear Information System (INIS)

Davis, William M.

1999-01-01

This project demonstrated two in-situ volatile organic compound (VOC) samplers in combination with the direct sampling ion trap mass spectrometer (DSITMS). The technologies chosen were the Vadose Sparge and the Membrane Interface Probe (MIP) sensing systems. Tests at two demonstration sites showed the newer VOC technologies capable of providing in situ contaminant measurements at two to four times the rate of the previously demonstrated Hydrosparge sensor. The results of this project provide initial results supporting the utility of these new technologies to provide rapid site characterization of VOC contaminants in the subsurface

Sorption of phenanthrene and benzene on differently structural kerogen: Important role of micropore-filling

International Nuclear Information System (INIS)

Zhang, Yulong; Ma, Xiaoxuan; Ran, Yong

2014-01-01

Shale was thermally treated to obtain a series of kerogen with varied maturation. Their chemical, structural and porous properties were related to the sorption and/or desorption behaviors of phenanthrene and benzene. As the treatment temperature increases, aliphatic and carbonyl carbon of the kerogen samples decrease, while their aromaticity and maturation increase. Meanwhile, the isothermal nonlinearity of phenanthrene and benzene increases whereas the sorption capacity and micropore adsorption volumes (V o,d ) initially increase and then decrease. The V o,d of benzene is significantly correlated with, but higher than that of phenanthrene, suggesting similar micropore filling mechanism and molecular sieve effect. The benzene desorption exhibits hysteresis, which is related to the pore deformation of the kerogen and the entrapment of solute in the kerogen matrix. The V o,d of phenanthrene and benzene on the kerogen samples accounts for 23–46% and 36–65% of the maximum sorption volumes, respectively, displaying the importance of the micropore filling. -- Highlights: • The microporosity estimated by benzene vapor differs greatly from that by N 2 . • The micropore volume changes with kerogen maturation. • The phenanthrene or benzene sorption is related to the microporosity of kerogen. • Higher adsorption volume for benzene than for phenanthrene suggests molecular sieve effect. • The pore-filling plays an important role in the sorption of phenanthrene and benzene. -- The sorption behaviors of benzene and phenanthrene are related to the microporosity of the differently matured kerogen, indicating the importance of pore-filling

Substrate interactions of benzene, toluene, and para-xylene during microbial degradation by pure cultures and mixed culture aquifer slurries

International Nuclear Information System (INIS)

Alvarez, P.J.J.; Vogel, T.M.

1991-01-01

Release of petroleum hydrocarbons in the environment is a widespread occurrence. One particular concern is the contamination of drinking water sources by the toxic, water-soluble, and mobile petroleum components benzene, toluene, and xylene (BTX). Benzene, toluene, and p-xylene (BTX) were degraded by indigenous mixed cultures in sandy aquifer material and by two pure cultures isolated from the same site. Although BTX compounds have a similar chemical structure, the fate of individual BTX compounds differed when the compounds were fed to each pure culture and mixed culture aquifer slurries. The identification of substrate interactions aided the understanding of this behavior. Beneficial substrate interactions included enhanced degradation of benzene-dependent degradation of toluene and p-xylene by Arthrobacter sp. strain HCB. Detrimental substrate interactions included retardation in benzene and toluene degradation by the presence of p-xylene in both aquifer slurries and Pseudomonas incubations. The catabolic diversity of microbes in the environment precludes generalizations about the capacity of individual BTX compounds to enhance or inhibit the degradation of other BTX compounds

Benzene degradation coupled with chlorate reduction in soil column study

NARCIS (Netherlands)

Tan, N.C.G.; Doesburg, van W.C.J.; Langenhoff, A.A.M.; Stams, A.J.M.

2006-01-01

Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene

Investigation of gasoline distributions within petrol stations: spatial and seasonal concentrations, sources, mitigation measures, and occupationally exposed symptoms.

Science.gov (United States)

Sairat, Theerapong; Homwuttiwong, Sahalaph; Homwutthiwong, Kritsana; Ongwandee, Maneerat

2015-09-01

We measured levels of VOCs and determined the distributions of benzene concentrations over the area of two petrol stations in all three seasons. Using the concentrations and sampling positions, we created isoconcentration contour maps. The average concentrations ranged 18-1288 μg m(-3) for benzene and 12-81 μg m(-3) for toluene. The contour maps indicate that high-level contours of benzene were found not only at the fuel dispenser areas but also at the storage tank refilling points, open drainage areas where gasoline-polluted wastewater was flowing, and the auto service center located within the station area. An assessment of the benzene to toluene ratio contour plots implicates that airborne benzene and toluene near the fuel dispenser area were attributed to gasoline evaporation although one of the studied stations may be influenced by other VOC sources besides gasoline evaporation. Additionally, during the routine refilling of the underground fuel storage tanks by a tank truck, the ambient levels of benzene and toluene increased tremendously. The implementation of source control by replacing old dispensers with new fuel dispensers that have an efficient cutoff feature and increased delivery speed can reduce spatial benzene concentrations by 77%. Furthermore, a questionnaire survey among 63 service attendants in ten stations revealed that headache was the most reported health complaint with a response rate of 32%, followed by fatigue with 20%. These prominent symptoms could be related to an exposure to high benzene concentrations.

An analysis of workplace exposures to benzene over four decades at a petrochemical processing and manufacturing facility (1962-1999).

Science.gov (United States)

Sahmel, J; Devlin, K; Burns, A; Ferracini, T; Ground, M; Paustenbach, D

2013-01-01

Benzene, a known carcinogen, can be generated as a by-product during the use of petroleum-based raw materials in chemical manufacturing. The aim of this study was to analyze a large data set of benzene air concentration measurements collected over nearly 40 years during routine employee exposure monitoring at a petrochemical manufacturing facility. The facility used ethane, propane, and natural gas as raw materials in the production of common commercial materials such as polyethylene, polypropylene, waxes, adhesives, alcohols, and aldehydes. In total, 3607 benzene air samples were collected at the facility from 1962 to 1999. Of these, in total 2359 long-term (>1 h) personal exposure samples for benzene were collected during routine operations at the facility between 1974 and 1999. These samples were analyzed by division, department, and job title to establish employee benzene exposures in different areas of the facility over time. Sampling data were also analyzed by key events over time, including changes in the occupational exposure limits (OELs) for benzene and key equipment process changes at the facility. Although mean benzene concentrations varied according to operation, in nearly all cases measured benzene quantities were below the OEL in place at the time for benzene (10 ppm for 1974-1986 and 1 ppm for 1987-1999). Decreases in mean benzene air concentrations were also found when data were evaluated according to 7- to 10-yr periods following key equipment process changes. Further, an evaluation of mortality rates for a retrospective employee cohort (n = 3938) demonstrated that the average personal benzene exposures at this facility (0.89 ppm for the period 1974-1986 and 0.125 ppm for the period 1987-1999) did not result in increased standardized mortality ratio (SMRs) for diseases or malignancies of the lymphatic system. The robust nature of this data set provides comprehensive exposure information that may be useful for assessing human benzene exposures at

Biodegradation of volatile organic compounds by five fungal species

Energy Technology Data Exchange (ETDEWEB)

Qi, B.; Moe, W.M. [Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA (United States); Kinney, K.A. [Dept. of Civil Engineering, Univ. of Texas, Austin (United States)

2002-07-01

Five fungal species, Cladosporium resinae (ATCC 34066), Cladosporium sphaerospermum (ATCC 200384), Exophiala lecanii-corni (CBS 102400), Mucor rouxii (ATCC 44260), and Phanerochaete chrysosporium (ATCC 24725), were tested for their ability to degrade nine compounds commonly found in industrial off-gas emissions. Fungal cultures inoculated on ceramic support media were provided with volatile organic compounds (VOCs) via the vapor phase as their sole carbon and energy sources. Compounds tested included aromatic hydrocarbons (benzene, ethylbenzene, toluene, and styrene), ketones (methyl ethyl ketone, methyl isobutyl ketone, and methyl propyl ketone), and organic acids (n-butyl acetate, ethyl 3-ethoxypropionate). Experiments were conducted using three pH values ranging from 3.5 to 6.5. Fungal ability to degrade each VOC was determined by observing the presence or absence of visible growth on the ceramic support medium during a 30-day test period. Results indicate that E. lecanii-corni and C. sphaerospermum can readily utilize each of the nine VOCs as a sole carbon and energy source. P. chrysosporium was able to degrade all VOCs tested except for styrene under the conditions imposed. C. resinae was able to degrade both organic acids, all of the ketones, and some of the aromatic compounds (ethylbenzene and toluene); however, it was not able to grow utilizing benzene or styrene under the conditions tested. With the VOCs tested, M. rouxii produced visible growth only when supplied with n-butyl acetate or ethyl 3-ethoxypropionate. Maximum growth for most fungi was observed at a pH of approximately 5.0. The experimental protocol utilized in these studies is a useful tool for assessing the ability of different fungal species to degrade gas-phase VOCs under conditions expected in a biofilter application. (orig.)

Nematicidal effect of volatile organic compounds (VOCs on the plant-parasitic nematode Meloidogyne javanica

Directory of Open Access Journals (Sweden)

Mauricio Batista Fialho

2012-06-01

Full Text Available Previous studies have demonstrated that volatile organic compounds (VOCs, produced by the yeast Saccharomyces cerevisiae, were able to inhibit the development of phytopathogenic fungi. In this context, the nematicidal potential of the synthetic mixture of VOCs, constituted of alcohols and esters, was evaluated for the control of the root-knot nematode Meloidogyne javanica, which causes losses to crops of high economic value. The fumigation of substrate containing second-stage juveniles with VOCs exhibited nematicidal effect higher than 30% for the lowest concentration tested (33.3 µL g-1 substrate, whereas at 66.6 and 133.3 µL g-1 substrate, the nematode mortality was 100%. The present results stimulate other studies on VOCs for nematode management.

Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants

Science.gov (United States)

Bracho-Nunez, A.; Knothe, , N. M.; Welter, S.; Staudt, M.; Costa, W. R.; Liberato, M. A. R.; Piedade, M. T. F.; Kesselmeier, J.

2013-09-01

Emission inventories defining regional and global biogenic volatile organic compounds (VOC) emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects). The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed heterogeneous emissions, including reactive VOC species which are not

Leaf level emissions of volatile organic compounds (VOC from some Amazonian and Mediterranean plants

Directory of Open Access Journals (Sweden)

A. Bracho-Nunez

2013-09-01

heterogeneous emissions, including reactive VOC species which are not easily detected by flux measurements, give reason to perform more screening at leaf level and, whenever possible, within the forests under ambient conditions.

Research on release rate of volatile organic compounds in typical vessel cabin

Directory of Open Access Journals (Sweden)

ZHANG Jinlan

2018-02-01

Full Text Available [Objectives] Volatile Organic Compounds (VOC should be efficiently controlled in vessel cabins to ensure the crew's health and navigation safety. As an important parameter, research on release rate of VOCs in cabins is required. [Methods] This paper develops a method to investigate this parameter of a ship's cabin based on methods used in other closed indoor environments. A typical vessel cabin is sampled with Tenax TA tubes and analyzed by Automated Thermal Desorption-Gas Chromatography-Mass Spectrometry (ATD-GC/MS. The lumped mode is used and the release rate of Benzene, Toluene, Ethylbenzene and Xylene (BTEX, the typical representatives of VOCs, is obtained both in closed and ventilated conditions. [Results] The results show that the content of xylene and Total Volatile Organic Compounds (TVOC exceed the indoor environment standards in ventilated conditions. The BTEX release rate is similar in both conditions except for the benzene. [Conclusions] This research builds a method to measure the release rate of VOCs, providing references for pollution character evaluation and ventilation and purification system design.

Sample preparation of environmental samples using benzene synthesis followed by high-performance LSC

International Nuclear Information System (INIS)

Filippis, S. De; Noakes, J.E.

1991-01-01

Liquid scintillation counting (LSC) techniques have been widely employed as the detection method for determining environmental levels of tritium and 14 C. Since anthropogenic and nonanthropogenic inputs to the environment are a concern, sampling the environment surrounding a nuclear power facility or fuel reprocessing operation requires the collection of many different sample types, including agriculture products, water, biota, aquatic life, soil, and vegetation. These sample types are not suitable for the direct detection of tritium of 14 C for liquid scintillation techniques. Each sample type must be initially prepared in order to obtain the carbon or hydrogen component of interest and present this in a chemical form that is compatible with common chemicals used in scintillation counting applications. Converting the sample of interest to chemically pure benzene as a sample preparation technique has been widely accepted for processing samples for radiocarbon age-dating applications. The synthesized benzene is composed of the carbon or hydrogen atoms from the original sample and is ideal as a solvent for LSC with excellent photo-optical properties. Benzene synthesis followed by low-background scintillation counting can be applied to the preparation and measurement of environmental samples yielding good detection sensitivities, high radionuclide counting efficiency, and shorter preparation time. The method of benzene synthesis provides a unique approach to the preparation of a wide variety of environmental sample types using similar chemistry for all samples

Urban and Industrial VOC Emissions in the Seoul Metropolitan Area and Surrounding Region during the KORUS-AQ Field Study

Science.gov (United States)

Simpson, I. J.; Blake, D. R.; Blake, N. J.; Meinardi, S.; Barletta, B.; Hughes, S.; Vizenor, N.; Emmons, L. K.; Barré, J.; Woo, J. H.; Kim, J.; Schroeder, J.; Knote, C. J.; Fried, A.; Armin, W.; Min, K. E.; Jeong, S.

2017-12-01

The Korea-United States Air Quality Study (KORUS-AQ) took place in May and June, 2016 to better understand air pollution in Korea. During the campaign 2650 whole air samples were collected aboard the NASA DC-8 aircraft and analyzed for more than 80 C1-C10 volatile organic compounds (VOCs), including alkanes, aromatics, alkenes, halocarbons and organic nitrates. Approximately 300 samples were collected at low altitude (health effects for facility workers and local residents. Ongoing work includes further clarifying specific source influences in the SMA, assessing emission inventories and the contribution of individual VOCs to ozone production, and linking the airborne data to ground-based measurements.

Story of skeletally substituted benzenes

Indian Academy of Sciences (India)

Unknown

values are extensively used to define aromaticity quantitatively.3 In a recent study on ... studies were directed to unravel the subtle ways in which the stability, reactivity, and ..... The singlet–triplet gaps of all the skeletally substituted benzenes ...

Status and Needs Research for On-line Monitoring of VOCs Emissions from Stationary Sources

Science.gov (United States)

Zhou, Gang; Wang, Qiang; Zhong, Qi; Zhao, Jinbao; Yang, Kai

2018-01-01

Based on atmospheric volatile organic compounds (VOCs) pollution control requirements during the twelfth-five year plan and the current status of monitoring and management at home and abroad, instrumental architecture and technical characteristics of continuous emission monitoring systems (CEMS) for VOCs emission from stationary sources are investigated and researched. Technological development needs of VOCs emission on-line monitoring techniques for stationary sources in china are proposed from the system sampling pretreatment technology and analytical measurement techniques.

Quantitative assessment of industrial VOC emissions in China: Historical trend, spatial distribution, uncertainties, and projection

Science.gov (United States)

Zheng, Chenghang; Shen, Jiali; Zhang, Yongxin; Huang, Weiwei; Zhu, Xinbo; Wu, Xuecheng; Chen, Linghong; Gao, Xiang; Cen, Kefa

2017-02-01

The temporal trends of industrial volatile organic compound (VOC) emissions was comprehensively summarized for the 2011 to 2013 period, and the projections for 2020 to 2050 for China were set. The results demonstrate that industrial VOC emissions in China increased from 15.3 Tg in 2011 to 29.4 Tg in 2013 at an annual average growth rate of 38.3%. Guangdong (3.45 Tg), Shandong (2.85 Tg), and Jiangsu (2.62 Tg) were the three largest contributors collectively accounting for 30.4% of the national total emissions in 2013. The top three average industrial VOC emissions per square kilometer were Shanghai (247.2 ton/km2), Tianjin (62.8 ton/km2), and Beijing (38.4 ton/km2), which were 12-80 times of the average level in China. The data from the inventory indicate that the use of VOC-containing products, as well as the production and use of VOCs as raw materials, as well as for storage and transportation contributed 75.4%, 10.3%, 9.1%, and 5.2% of the total emissions, respectively. ArcGIS was used to display the remarkable spatial distribution variation by allocating the emission into 1 km × 1 km grid cells with a population as surrogate indexes. Combined with future economic development and population change, as well as implementation of policy and upgrade of control technologies, three scenarios (scenarios A, B, and C) were set to project industrial VOC emissions for the years 2020, 2030, and 2050, which present the industrial VOC emissions in different scenarios and the potential of reducing emissions. Finally, the result shows that the collaborative control policies considerably influenced industrial VOC emissions.

Evaluation of the efficiency of an experimental biocover to reduce BTEX emissions from landfill biogas.

Science.gov (United States)

Lakhouit, Abderrahim; Schirmer, Waldir N; Johnson, Terry R; Cabana, Hubert; Cabral, Alexandre R

2014-02-01

Landfill emissions include volatile organic compounds (VOCs) and, particularly, benzene, toluene, ethyl-benzene and xylene isomers (collectively called BTEX). The latter are the most common VOCs found in landfill biogas. BTEX affect air quality and may be harmful to human health. In conjunction with a study aiming to evaluate the efficiency of passive methane oxidizing biocovers, a complementary project was developed with the specific goal of evaluating the reduction in VOC emissions due to the installation of a biocover. One of the biocovers constructed at the Saint-Nicéphore (Quebec, Canada) landfill site was instrumented for this purpose. The total BTEX concentration in the raw biogas ranged from 28.7 to 65.4ppmv, and the measured concentration of BTEX in biogas emitted through the biocover ranged from below the limit of detection (BLD) to 2.1ppmv. The other volatile organic compounds (OVOCs) concentration varied from 18.8 to 40.4ppmv and from 0.8 to 1.2ppmv in the raw biogas and in the emitted biogas, respectively. The results obtained showed that the biocover effectiveness ranged from 67% to 100% and from 96% to 97% for BTEX and OVOC, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

High-efficiency plasma catalytic removal of dilute benzene from air

International Nuclear Information System (INIS)

Fan, Hong-Yu; Shi, Chuan; Li, Xiao-Song; Zhao, De-Zhi; Xu, Yong; Zhu, Ai-Min

2009-01-01

Achieving complete oxidation, good humidity tolerance and low energy cost is the key issue that needs to be addressed in plasma catalytic volatile organic compounds removal from air. For this purpose, Ag/HZSM-5 catalyst-packed dielectric barrier discharge using a cycled system composed of a storage stage and a discharge stage was studied. For dilute benzene removal from simulated air, Ag/HZSM-5 catalysts exhibit not only preferential adsorption of benzene in humid air at the storage stage but also almost complete oxidation of adsorbed benzene at the discharge stage. Five 'storage-discharge' cycles were examined, which suggests that Ag/HZSM-5 catalysts are very stable during the cycled 'storage-discharge' (CSD) plasma catalytic process. High oxidation rate of absorbed benzene as well as low energy cost can be achieved at a moderate discharge power. In an example of the CSD plasma catalytic remedy of simulated air containing 4.7 ppm benzene with 50% RH and 600 ml min -1 flow rate, the energy cost was as low as 3.7 x 10 -3 kWh m -3 air. This extremely low energy cost to remove low-concentration pollutants from air undoubtedly makes the environmental applications of the plasma catalytic technique practical.

VOC emission into the atmosphere by trees and leaf litter in Polish forests

Science.gov (United States)

Isidorov, V.; Smolewska, M.; Tyszkiewicz, Z.

2009-04-01

It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important, evaluations for individual countries are also very important. This poster represents the results of the estimation of VOC emission from Polish forests. Calculations took into account the composition and age of forests. According to our estimation, the total VOC emission by the arboreal vegetation differs from 190 to 750 kt/yr, depending of weather conditions in different years. There are only few studies conducted on decaying plant material as a source of atmospheric VOCs, but still they are able to give evidence of the importance of this source. For Polish forests, the litter mass is estimated to be (16-19)106 t/yr. These organic materials undergo decomposition by mesofauna and microorganisms. In these processes volatile organic compounds (VOC) stored in the litter and secondary metabolites of litter-destroying fungi are emitted into the atmosphere. The scale of the phenomenon makes leaf litter an important VOC source in the atmosphere. The filling of numerous gaps in researches of VOC emissions from decomposing leaf litter demands carrying out of long term field experiments in various climatic conditions. In this communication we report also the results of 3.5-year experiment on qualitative and quantitative GC-MS investigations of VOC emitted into the gas phase from leaves litter of some species of deciduous and coniferous trees of Polish forests. Apart from terpenes and their oxygenated derivatives, which are usual in plant tissues, leaf litter intensively emits vast amounts of lower alcohols and carbonyl compounds. We suppose that these volatile substances are products

On the dating of você, ocê and senhorita

Directory of Open Access Journals (Sweden)

Odete Pereira da Silva Menon

2009-11-01

Full Text Available Knowing the date when a word first appeared in the language is not only helpful for linguistic dating purposes. This information is important because it can guide studies about the actuation problem and evaluation stages (WEINREICH; LABOV; HERZOG, 1968 of linguistic changes. The present study is an attempt to locate, historically and socially, the behavior of forms to address the interlocutor, using more grammaticalized variants of the pronoun (honorific form vossa mercê, first in Portugal (você — you, en English then in Brazil (você and ocê/cê — contracted forms of você , correcting, updating and fixing the appearance dates of these occurrences. By referring to literature authors born between the 17th Century and the beginning of the 20th Century it was also possible to anticipate by half a century the dating of the noun senhorita (Eng. mistress, maybe an indicator of a new statute for women.

Benzene - exposure and risk evaluation; Benzol - Exposition und Risikoabschaetzung

Energy Technology Data Exchange (ETDEWEB)

Eikmann, T. [Giessen Univ. (Germany). Hygiene-Institut und Umweltmedizin; Eikmann, S. [Gesellschaft fuer Umwelttoxikologie und Krankenhaushygiene mbH, Wetzlar (Germany); Goeen, T. [Technische Hochschule Aachen (Germany). Inst. fuer Hygiene und Arbeitsmedizin

2000-07-01

Benzene is one of the most important environmental carcinogens. Because of its potential to induce leukemia, benzene is noted as carcinogeneous hazardous substance in legal guidelines for occupational use and environmental contact. Epidemiological studies resulted to unit-risk values between 2.8 x 10{sup -6} to 30 x 10{sup -6} for lifelong exposure to 1 {mu}g/m{sup 3} benzene. In Germany, the average unit-risk was estimated to be 9 x 10{sup -6}. The general population is mainly exposed to benzene due to the emissions of motor vehicles. The average annual air concentration of benzene at main roads and in industrial areas are 5 to 30 {mu}g/m{sup 3}. Due to seasonal influences and special exposure situations distinctly higher peak concentrations are occurring. Regional differences, i.e. between rural and urban immission levels and between the concentration in air of the northern and southern part of Europe, are also recognizable. The life-style factor smoking increases the individual exposure distinctly, whereas contamination of the diet contribute little to the total uptake of benzene. The internal exposure of the general population varies due to living area, smoking habits and mobility. Individuals living in no-smoking buildings show benzene concentrations in blood of 15 to 170 ng/l, whereas the benzene level of persons with additional exposures (smoking, frequently use of motor vehicles, etc.) can reach approximately 1000 ng/l blood. Comparable conclusions result from data for the urinary levels of two sensitive metabolites of benzene: trans-, trans-muconic acid and S-phenylmercapturic acid. (orig.) [German] Benzol stellt aufgrund seines ubiquitaeren Auftretens und seiner Leukaemie verursachenden Wirkung eines der bedeutendsten Umweltkanzerogene dar. Es ist als krebserzeugender Gefahrstoff (Gefahrstoffverordnung: Gruppe II) und als eindeutig krebserzeugender Arbeitsstoff (Kategorie 1) ausgewiesen. Aus epidemiologischen Studien ergaben sich Unit

Degradative capacities and bioaugmentation potential of an anaerobic benzene-degrading bacterium strain DN11

Energy Technology Data Exchange (ETDEWEB)

Yuki Kasai; Yumiko Kodama; Yoh Takahata; Toshihiro Hoaki; Kazuya Watanabe [Marine Biotechnology Institute, Kamaishi (Japan)

2007-09-15

Azoarcus sp. strain DN11 is a denitrifying bacterium capable of benzene degradation under anaerobic conditions. The present study evaluated strain DN11 for its application to bioaugmentation of benzene-contaminated underground aquifers. Strain DN11 could grow on benzene, toluene, m-xylene, and benzoate as the sole carbon and energy sources under nitrate-reducing conditions, although o- and p-xylenes were transformed in the presence of toluene. Phenol was not utilized under anaerobic conditions. Kinetic analysis of anaerobic benzene degradation estimated its apparent affinity and inhibition constants to be 0.82 and 11 {mu}M, respectively. Benzene-contaminated groundwater taken from a former coal-distillation plant site in Aichi, Japan was anaerobically incubated in laboratory bottles and supplemented with either inorganic nutrients (nitrogen, phosphorus, and nitrate) alone, or the nutrients plus strain DN11, showing that benzene was significantly degraded only when DN11 was introduced. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments, and quantitative PCR revealed that DN11 decreased after benzene was degraded. Following the decrease in DN11 16S rRNA gene fragments corresponding to bacteria related to Owenweeksia hongkongensis and Pelotomaculum isophthalicum, appeared as strong bands, suggesting possible metabolic interactions in anaerobic benzene degradation. Results suggest that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations. 50 refs., 6 figs., 1 tab.

Biomonitoring-based exposure assessment of benzene, toluene, ethylbenzene and xylene among workers at petroleum distribution facilities.

Science.gov (United States)

Heibati, Behzad; Godri Pollitt, Krystal J; Charati, Jamshid Yazdani; Ducatman, Alan; Shokrzadeh, Mohammad; Karimi, Ali; Mohammadyan, Mahmoud

2018-03-01

Elevated emissions of volatile organic compounds, including benzene, toluene, ethylbenzene, and o, p, and m-xylenes (BTEX), are an occupational health concern at oil transfer stations. This exploratory study investigated personal exposure to BTEX through environmental air and urine samples collected from 50 male workers at a major oil distribution company in Iran. Airborne BTEX exposures were evaluated over 8h periods during work-shift by using personal passive samplers. Urinary BTEX levels were determined using solid-phase microextraction with gas chromatography mass spectrometry for separation and detection. Mean exposure to ambient concentrations of benzene differed by workers' job type: tanker loading workers (5390μg/m 3 ), tank-gauging workers (830μg/m 3 ), drivers (81.9μg/m 3 ), firefighters (71.2μg/m 3 ) and office workers (19.8μg/m 3 ). Exposure across job type was similarly stratified across all personal exposures to BTEX measured in air samples with maximum concentrations found for tanker loading workers. Average exposures concentrations of BTEX measured in urine were 11.83 ppb benzene, 1.87 ppb toluene, 0.43 ppb ethylebenzene, and 3.76 ppb xylene. Personal air exposure to benzene was found to be positively associated with benzene concentrations measured in urine; however, a relationship was not observed to the other BTEX compounds. Urinary exposure profiles are a potentially useful, noninvasive, and rapid method for assessing exposure to benzene in a developing and relatively remote production region. Copyright © 2017 Elsevier Inc. All rights reserved.

Low VOC Barrier Coating for Industrial Maintenance

Science.gov (United States)

2012-09-01

VOC Total Solids (wt) Total Solids (volume) Percent Pigment Stormer Viscosity Brookfield Viscosity Pot Life Sag Resistance Theoretical...Percent Pigment – Stormer Viscosity – Brookfield Viscosity – Pot Life – Sag Resistance – Theoretical Coverage – Drying Times – Mixing Ratio

Sesquiterpene volatile organic compounds (VOCs are markers of elicitation by sulfated laminarine in grapevine

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Malik eChalal

2015-05-01

Full Text Available Inducing resistance in plants by application of elicitors of defense reactions is an attractive plant protection strategy, especially for grapevine (Vitis vinifera which is susceptible to severe fungal diseases. Though induced resistance (IR can be successful in controlled conditions, under outdoor conditions IR is in most cases not effective enough for practical disease control. Progress in the application of IR requires a better understanding of grapevine defense mechanisms and the ability to monitor defense markers in order to identify factors (physiological, environmental… that can impact IR in the vineyard.Volatile organic compounds (VOCs are well-known plant defenses compounds that have only received little or no attention in the case of grape-pathogen interactions to date. This prompted us to investigate whether an elicitor, the sulfated laminarin (PS3, actually induces the production of VOCs in grapevine. Online analysis (PTR-QMS of VOC emissions in dynamic cuvettes and passive sampling in gas tight bags with solid phase micro extraction (SPME-GC-MS under greenhouse conditions showed that PS3 elicited emission of VOCs. Some of them (as (E,E-α-farnesene might be good candidates as biomarkers of elicitor-IR whereas methyl salicylate appears to be rather a biomarker of downy mildew infection. A negative correlation between VOC emission and disease severity suggests a positive role of VOCs in grape defense against diseases.

A Review of Photocatalysts Prepared by Sol-Gel Method for VOCs Removal

Directory of Open Access Journals (Sweden)

Ting Ke Tseng

2010-05-01

Full Text Available The sol-gel process is a wet-chemical technique (chemical solution deposition, which has been widely used in the fields of materials science, ceramic engineering, and especially in the preparation of photocatalysts. Volatile organic compounds (VOCs are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO is regarded as a promising method. This paper is a review of the status of research on the sol-gel method for photocatalyst preparation and for the PCO purification of VOCs. The review and discussion will focus on the preparation and coating of various photocatalysts, operational parameters, and will provide an overview of general PCO models described in the literature.

Mineral-like clathrate of cadmium cyanide with benzene

International Nuclear Information System (INIS)

Kitazava, T.; Nishimura, A.

1999-01-01

A new mineral-like clathrate of cadmium cyanide with benzene Cd(CN) 2 ·C 6 H 6 is prepared. Data of x-ray diffraction analysis show that benzene molecule is incorporated in cadmium cyanide lattice and a new mineral-like lattice of Cd(CN) 2 belongs to structures of cristobalite type. Clathrate Cd(CN) 2 ·C 6 H 6 crystallizes in trigonal space group R3m, a=8.953(4), c=21929(6) A [ru

A self-consistent, multivariate method for the determination of gas-phase rate coefficients, applied to reactions of atmospheric VOCs and the hydroxyl radical