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Sample records for vocs including toluene

  1. Adsorption of vapor-phase VOCs (benzene and toluene) on modified clays and its relation with surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Cortes, C.; Gallardo-Velazquez, T.; Arellano-Cardenas, S. [National School of Biological Sciences (Mexico). Biophysics Dept.; Osorio-Revilla, G. [National School of Biological Sciences (Mexico). Biochemical Engineering Dept.

    2008-04-15

    A study was conducted to investigate the potential use of modified clays for the adsorption of volatile organic compounds (VOCs) present in air. These VOCs which include toluene and benzene, are among the main air pollutants that represent a human health risk at high concentrations, mostly in indoor environments. In this study, a Mexican bentonite was used to prepare 3 modified clays, notably an organoclay (OC-CPC) by intercalating cetylpyridinium chloride (CPC); an aluminum-pillared clay (Al-PILC); and an inorganic-organic clay (IOC-CPC) prepared from Al-PILC intercalating CPC. Their structures were differentiated by infrared and thermogravimetric analyses, and the interlayer distance was assessed through X-ray diffraction. Toluene and benzene adsorption on OC-CPC was higher than in IOC-CPC and Al-PILC. Natural clay showed no adsorption capacity for these compounds. Comparison of the gas chromatography retention times for non polar and low-polarity compounds (octyne and benzene) in columns packed with OC-CPC and a commercial non polar column (squalene) showed that the OC-CPC possessed a higher organophilic (non polar) nature than squalene. This explains the higher benzene and toluene adsorption capacity of the OC-CPC compared with the other modified clays. It was concluded that organoclays represent a potential alternative for the adsorption of volatile organic compounds such as benzene and toluene present in indoor environments. Since the OC-CPC is hydrophobic by nature, the relative humidity of water vapour in the environment would not affects its adsorption capacity. 27 refs., 5 tabs., 5 figs.

  2. Integrated Anaerobic-Aerobic Biodegradation of Multiple Contaminants Including Chlorinated Ethylenes, Benzene, Toluene, and Dichloromethane.

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

    Complete bioremediation of soils containing multiple volatile organic compounds (VOCs) remains a challenge. To explore the possibility of complete bioremediation through integrated anaerobic-aerobic biodegradation, laboratory feasibility tests followed by alternate anaerobic-aerobic and aerobic-anaerobic biodegradation tests were performed. Chlorinated ethylenes, including tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC), and dichloromethane (DCM) were used for anaerobic biodegradation, whereas benzene, toluene, and DCM were used for aerobic biodegradation tests. Microbial communities involved in the biodegradation tests were analyzed to characterize the major bacteria that may contribute to biodegradation. The results demonstrated that integrated anaerobic-aerobic biodegradation was capable of completely degrading the seven VOCs with initial concentration of each VOC less than 30 mg/L. Benzene and toluene were degraded within 8 days, and DCM was degraded within 20 to 27 days under aerobic conditions when initial oxygen concentrations in the headspaces of test bottles were set to 5.3% and 21.0%. Dehalococcoides sp., generally considered sensitive to oxygen, survived aerobic conditions for 28 days and was activated during the subsequent anaerobic biodegradation. However, degradation of cis-DCE was suppressed after oxygen exposure for more than 201 days, suggesting the loss of viability of Dehalococcoides sp., as they are the only known anaerobic bacteria that can completely biodegrade chlorinated ethylenes to ethylene. Anaerobic degradation of DCM following previous aerobic degradation was complete, and yet-unknown microbes may be involved in the process. The findings may provide a scientific and practical basis for the complete bioremediation of multiple contaminants in situ and a subject for further exploration.

  3. Diffusion-controlled toluene reference material for VOC emissions testing: international interlaboratory study.

    Science.gov (United States)

    Howard-Reed, Cynthia; Liu, Zhe; Cox, Steven; Leber, Dennis; Samarov, Dan; Little, John C

    2014-04-01

    The measurement of volatile organic compound (VOC) emissions from building products and materials by manufacturers and testing laboratories, and the use of the test results for labeling programs, continue to expand. One issue that hinders wide acceptance for chamber product testing is the lack of a reference material to validate test chamber performance. To meet this need, the National Institute of Standards and Technology (NIST) and Virginia Tech (VT) have developed a prototype reference material that emits a single VOC similar to the emissions of a diffusion-controlled building product source with a dynamic emissions profile. The prototype material has undergone extensive testing at NIST and a pilot interlaboratory study (ILS) with four laboratories. The next development step is an evaluation of the prototype source in multiple-sized chambers of 14 laboratories in seven countries. Each laboratory was provided duplicate specimens and a test protocol. Study results identified significant issues related to the need to store the source at a subzero Celsius temperature until tested and possible inconsistencies in large chambers. For laboratories using a small chamber and meeting all the test method criteria, the results were very encouraging with relative standard deviations ranging from 5% to 10% across the laboratories. Currently, the chamber performance of laboratories conducting product VOC emissions testing is assessed through interlaboratory studies (ILS) using a source with an unknown emission rate. As a result, laboratory proficiency can only be based on the mean and standard deviation of emission rates measured by the participating ILS laboratories. A reference material with a known emission rate has the potential to provide an independent assessment of laboratory performance as well as improve the quality of interlaboratory studies. Several international laboratories with different chamber testing systems demonstrated the ability to measure the emission rate

  4. Chemical absorption process for degradation of VOC gas using heterogeneous gas-liquid photocatalytic oxidation: toluene degradation by photo-Fenton reaction.

    Science.gov (United States)

    Tokumura, Masahiro; Nakajima, Rina; Znad, Hussein Tawfeek; Kawase, Yoshinori

    2008-10-01

    A novel process for degradation of toluene in the gas-phase using heterogeneous gas-liquid photocatalytic oxidation has been developed. The degradation of toluene gas by photo-Fenton reaction in the liquid-phase has experimentally examined. The photo-Fenton reaction in the liquid-phase could improve the overall toluene absorption rate by increasing the driving force for mass transfer and as a result enhance the removal of toluene in the exhaust gas. The toluene concentrations in the inlet gas were varied in the range from 0.0968 to 8.69 g m(-3) with initial hydrogen peroxide concentration of 400 mg l(-1) and Fe dose of 5.0 mg l(-1). It was found that toluene in the inlet gas was almost completely dissolved into water and degraded in the liquid-phase for the inlet toluene gas concentration of less than 0.42 g m(-3). The dynamic process of toluene gas degradation by the photo-Fenton reaction providing information for reaction kinetics and mass transfer rate was examined. Toluene removal kinetic analysis indicated that photo-Fenton degradation was significantly affected by H(2)O(2) concentration. The experimental results were satisfactorily described by the predictions simulated using the simplified tanks-in-series model combined with toluene removal kinetic analysis. The present results showed that the proposed chemical absorption process using the photo-Fenton heterogeneous gas-liquid photocatalytic oxidation is very effective for degradation of volatile organic gases.

  5. A Kinetic Modeling study on the Oxidation of Primary Reference Fuel?Toluene Mixtures Including Cross Reactions between Aromatics and Aliphatics

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Y; Miyoshi, A; Koshi, M; Pitz, W J

    2008-01-09

    A detailed chemical kinetic model for the mixtures of Primary Reference Fuel (PRF: n-heptane and iso-octane) and toluene has been proposed. This model is divided into three parts; a PRF mechanism [T. Ogura et al., Energy & Fuels 21 (2007) 3233-3239], toluene sub-mechanism and cross reactions between PRF and toluene. Toluene sub-mechanism includes the low temperature kinetics relevant to engine conditions. A chemical kinetic mechanism proposed by Pitz et al. [Proc. the 2nd Joint Meeting of the U.S. Combust. Institute (2001)] was used as a starting model and modified by updating rate coefficients. Theoretical estimations of rate coefficients were performed for toluene and benzyl radical reactions important at low temperatures. Cross-reactions between alkane, alkene, and aromatics were also included in order to account for the acceleration by the addition of toluene into iso-octane recently found in the shock tube study of the ignition delay [Y. Sakai et al, SAE 2007-01-4014 (2007)]. Validations of the model were performed with existing shock tube and flow tube data. The model well predicts the ignition characteristics of toluene and PRF/Toluene mixtures under the wide range of temperatures (500-1700 K) and pressures (2-50 atm). It is found that reactions of benzyl radical with oxygen molecule determine the reactivity of toluene at low temperature. Although the effect of toluene addition to iso-octane is not fully resolved, the reactions of alkene with benzyl radical have the possibility to account for the kinetic interactions between PRF and toluene.

  6. Assessment of Volatile Organic Compounds (VOCs) in indooor parking facilities at Houston, Texas

    Science.gov (United States)

    Kristanto, Gabriel Andari

    This dissertation identified the types, magnitudes, sources, and assessed risk exposure of VOCs in different types of indoor parking facilities. VOCs are ones of major pollutants emitted from automobiles. The indoor parking facilities included were attached garages, grounds, and underground parking. Modification of method TO15 by EPA had been applied for identifying types and magnitudes of VOCs. Results of these identifications are presented. Eight most abundant VOCs could be identified in every sampling location with toluene as the most abundant compound followed by m,p-xylene, ethylbenzene and benzene. Compare to ground and underground parking, attached garages have the highest concentration of TVOCs. For sources identification, BTEX, m,p-xylene and benzene, and toluene and benzene ratios are calculated. BTEX ratios for ground and underground parking are similar compare to attached garage due to the similar pattern of driving speed and the content of gasoline fuel. On the other hand the ratios of m,p-xylene and benzene and toluene and benzene in attached garage are higher compare to the same ratios for ground and underground parking due to other significant contributor of VOCs such as solvent, household cleanings stored. Cancer and noncancer risk assessment were also calculated. Results showed that cancer and noncancer risk due human exposures to VOC in indoor parking facilities were relatively low. However the risk of the human exposure to VOCs from indoor parking facilities has to be considered as a part of total risks of VOC exposures on human during their daily activities. When people in Houston have already exposed to high VOC concentrations from outdoor environment activities such as traffic and refineries and petrochemical facilities, additional activities causing VOC exposures will add the risk significantly.

  7. An extended baseline examination of indoor VOCs in a city of low ambient pollution: Perth, Western Australia

    Science.gov (United States)

    Maisey, S. J.; Saunders, S. M.; West, N.; Franklin, P. J.

    2013-12-01

    This study of indoor air quality reports VOC concentrations in 386 suburban homes located in Perth Western Australia, a city of low ambient pollution and temperate climate. Details of indoor VOC concentrations, temperature, relative humidity, and information on house characteristics and occupant activities were collected during the sampling periods. The concentration of VOCs observed in typical homes was low and individual compounds rarely exceeded 5 μg m-3. Median individual VOC concentrations ranged from 0.06 μg m-3 for 1,1,1 trichloroethane and butyl ether to 26.6 μg m-3 for cis/trans 2-butene. Recently renovated homes had higher concentrations of VOCs than non renovated homes, includingVOCs (p = 0.026), ∑BTEX (p = 0.03), ∑xylene (p = 0.013), toluene (p = 0.05), cyclohexane (p = 0.039), and propyl benzene (p = 0.039). Statistical analyses showed house age and attached garages were not significant factors for any of the VOCs tested. The concentrations of indoor VOCs in Perth were lower than overseas observations and those reported in recent Australian studies, with inferences made to differences in the climate and the occupant behaviour. The results are a baseline profile of indoor VOCs over the period 2006-2011, in an Australian city of low population density and of generally low ambient pollution.

  8. Oxidation of trichloroethylene, toluene, and ethanol vapors by a partially saturated permeable reactive barrier

    Science.gov (United States)

    Mahmoodlu, Mojtaba G.; Hassanizadeh, S. Majid; Hartog, Niels; Raoof, Amir

    2014-08-01

    The mitigation of volatile organic compound (VOC) vapors in the unsaturated zone largely relies on the active removal of vapor by ventilation. In this study we considered an alternative method involving the use of solid potassium permanganate to create a horizontal permeable reactive barrier for oxidizing VOC vapors. Column experiments were carried out to investigate the oxidation of trichloroethylene (TCE), toluene, and ethanol vapors using a partially saturated mixture of potassium permanganate and sand grains. Results showed a significant removal of VOC vapors due to the oxidation. We found that water saturation has a major effect on the removal capacity of the permeable reactive layer. We observed a high removal efficiency and reactivity of potassium permanganate for all target compounds at the highest water saturation (Sw = 0.6). A change in pH within the reactive layer reduced oxidation rate of VOCs. The use of carbonate minerals increased the reactivity of potassium permanganate during the oxidation of TCE vapor by buffering the pH. Reactive transport of VOC vapors diffusing through the permeable reactive layer was modeled, including the pH effect on the oxidation rates. The model accurately described the observed breakthrough curve of TCE and toluene vapors in the headspace of the column. However, miscibility of ethanol in water in combination with produced water during oxidation made the modeling results less accurate for ethanol. A linear relationship was found between total oxidized mass of VOC vapors per unit volume of permeable reactive layer and initial water saturation. This behavior indicates that pH changes control the overall reactivity and longevity of the permeable reactive layer during oxidation of VOCs. The results suggest that field application of a horizontal permeable reactive barrier can be a viable technology against upward migration of VOC vapors through the unsaturated zone.

  9. Effect of resin content and substrate on the emission of BTEX and carbonyls from low-VOC water-based wall paint.

    Science.gov (United States)

    Zhao, Ping; Cheng, Yu-Hsiang; Lin, Chi-Chi; Cheng, Yu-Lin

    2016-02-01

    The primary aim of this work is to explore the effect of resin content and the effect of substrate on the emission of benzene, toluene, ethylbenzene, and xylene (BTEX) and carbonyls from low-VOC water-based wall paint. Four low-volatile organic compound (VOC) paints include paints A (20% acrylic), B (30% acrylic), C (20% polyvinyl acetate), and D (30% polyvinyl acetate) were painted on stainless steel specimen for the study of resin effect. Green calcium silicate, green cement, and stainless steel were painted with paints A and C for the study of substrate effect. Concentrations of the VOCs in the chamber decreased with the elapsed time. Both resin type and resin quantity in paint had effects on VOC emissions. Paints with acrylic resin emitted less BTEX and carbonyls than paints with polyvinyl acetate resin. However, the effects of resin quantity varied with VOCs. Porous substrates were observed to interact more strongly with paints than inert substrates. Both green calcium silicate and green cement substrates have strong power of adsorption of VOCs from wall paints, namely toluene, formaldehyde, acetaldehyde, 2-butanone, methacrolein, butyraldehyde, and benzaldehyde. Some compounds like toluene, formaldehyde, and butyaldehyde were desorbed very slowly from green calcium silicate and green cement substrates.

  10. Acute and Subchronic Toxicity of Inhaled Toluene in Male ...

    Science.gov (United States)

    The effects of exposure to volatile organic compounds (VOCs), which are of concern to the EPA, are poorly understood, in part because of insufficient characterization of how human exposure duration impacts VOC effects. Two inhalation studies with multiple endpoints, one acute and one subchronic, were conducted to seek effects of the VOC, toluene, in rats and to compare the effects between acute and subchronic exposures. Adult male Long-Evans rats were exposed to toluene vapor (n = 6 per group) at a concentration of 0 or l 019 ± 14 ppm for 6 h in the acute study and at 0 ± 0, 10 ± 1.4, 97 ± 7, or 995 ± 43 ppm for 6 h/d, 5 d/week for 13 weeksin the subchronic study. For the acute study, brains were dissected on ice within 30 min of the end of exposure, while for the subchronic study, brains were dissected 18 h after the last exposure. Frontal cortex, hippocampus, cerebellum, and striatum were assayed for a variety of oxidative stress (OS) parameters including total aconitase (TA), protein carbonyls, glutathione peroxidase (GPX), glutathione reductase (GRD), glutathione transferase (GST), y-­glutamylcysteine synthetase (GCS), superoxide dismutase (SOD), total antioxidants (TAS), NADPH quinone oxidoreductase- 1 (NQO1 ), and NADH ubiquinone reductase (UBIQ-RD) activities using commercially available kits. Following acute exposure, UBIQ-RD, GCS and GRD were increased significantly only in the cerebellum, while TAS was increased in frontal cortex. On the other

  11. Spatial/temporal variations and source apportionment of VOCs monitored at community scale in an urban area.

    Directory of Open Access Journals (Sweden)

    Chang Ho Yu

    Full Text Available This study aimed to characterize spatial/temporal variations of ambient volatile organic compounds (VOCs using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile sites in Paterson and one background site in Chester, NJ (located ∼58 km southwest of Paterson. Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (p<0.01. Ethylbenzene, m,p-xylene, o-xylene, and p-dichlorobenzene measured at the commercial site were significantly higher than the industrial/mobile sites (p<0.01. Seven VOCs (acetylene, benzene, dichloromethane, methyl ethyl ketone, styrene, toluene, and p-dichlorobenzene were significantly different by season (p<0.05, that is, higher in cold seasons than in warm seasons. In addition, dichloromethane, methyl ethyl ketone, and toluene were significantly higher on weekdays than weekend days (p<0.05. These results are consistent with literature data, indicating the impact of anthropogenic VOC sources on air pollution in Paterson. Positive Matrix Factorization (PMF analysis was applied for 24-hour integrated VOC measurements in Paterson over one year and identified six contributing factors, including motor vehicle exhausts (20%, solvents uses (19%, industrial emissions (16%, mobile+stationery sources (12%, small shop emissions (11%, and others (22%. Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in

  12. Effect of surfactant and oil additions in the biodegradation of hexane and toluene vapours in batch tests.

    Science.gov (United States)

    Galindo, H; Revah, S; Cervantes, F J; Arriaga, S

    2011-01-01

    The biological treatment of gaseous emissions of hydrophobic volatile organic compounds (VOCs) results in low rates of elimination partially because of the low solubility of VOCs in water. Recently, the use of two-phase partition bioreactors (TPPBs) was proposed to increase the bioavailability and consequently the elimination capacities of this kind of VOC. In the present study, TPPBs operating in a batch feed mode were tested for biodegradation of hexane and toluene vapours with a microbial consortium. The results obtained were compared with single-phase systems (control experiments). The liquid phase used was silicone oil (organic phase) with the surfactant Pluronic F-68. Experiments were named F1 and F2 for one and two phases, respectively, and F(1S) and F(2S) when the surfactant was included. The maximum specific rates (S(rates)) of hydrocarbon consumption for hexane and toluene were 539 and 773 mg(hydrocarbon)/(g(protein) x h), respectively. For both substrates, the systems that showed the highest S(rates) of hydrocarbon consumption were F2 and F(2S). In experiment F(1S) the surfactant Pluronic F-68 increased the solubility of hydrocarbons in the liquid phase, but did not increase the S(rates). The maximum percentages of mineralization were 51% and 72% for hexane and toluene, respectively. The results showed that simultaneous addition of silicone oil and surfactant favours the mineralization, but not the rate ofbiodegradation, of toluene and hexane vapours.

  13. Decomposition characteristics of toluene by a corona radical shower system

    Institute of Scientific and Technical Information of China (English)

    WU Zu-liang; GAO Xiang; LUO Zhong-yang; NI Ming-jiang; CEN Ke-fa

    2004-01-01

    Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds(VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas.

  14. Kinetics of Hydrogen Radical Reactions with Toluene Including Chemical Activation Theory Employing System-Specific Quantum RRK Theory Calibrated by Variational Transition State Theory.

    Science.gov (United States)

    Bao, Junwei Lucas; Zheng, Jingjing; Truhlar, Donald G

    2016-03-02

    Pressure-dependent reactions are ubiquitous in combustion and atmospheric chemistry. We employ a new calibration procedure for quantum Rice-Ramsperger-Kassel (QRRK) unimolecular rate theory within a chemical activation mechanism to calculate the pressure-falloff effect of a radical association with an aromatic ring. The new theoretical framework is applied to the reaction of H with toluene, which is a prototypical reaction in the combustion chemistry of aromatic hydrocarbons present in most fuels. Both the hydrogen abstraction reactions and the hydrogen addition reactions are calculated. Our system-specific (SS) QRRK approach is adjusted with SS parameters to agree with multistructural canonical variational transition state theory with multidimensional tunneling (MS-CVT/SCT) at the high-pressure limit. The new method avoids the need for the usual empirical estimations of the QRRK parameters, and it eliminates the need for variational transition state theory calculations as a function of energy, although in this first application we do validate the falloff curves by comparing SS-QRRK results without tunneling to multistructural microcanonical variational transition state theory (MS-μVT) rate constants without tunneling. At low temperatures, the two approaches agree well with each other, but at high temperatures, SS-QRRK tends to overestimate falloff slightly. We also show that the variational effect is important in computing the energy-resolved rate constants. Multiple-structure anharmonicity, torsional-potential anharmonicity, and high-frequency-mode vibrational anharmonicity are all included in the rate computations, and torsional anharmonicity effects on the density of states are investigated. Branching fractions, which are both temperature- and pressure-dependent (and for which only limited data is available from experiment), are predicted as a function of pressure.

  15. Ambient levels and temporal trends of VOCs, including carbonyl compounds, and ozone at Cabañeros National Park border, Spain

    Science.gov (United States)

    Villanueva, Florentina; Tapia, Araceli; Notario, Alberto; Albaladejo, José; Martínez, Ernesto

    2014-03-01

    Concentration levels of 15 carbonyls, 17 VOCs and ozone were studied at Cabañeros National Park border, Spain, in an area mainly constituted by holm oaks (Quercus ilex) and cork oaks (Quercus suber), along with scrubland formations such as rock-rose and heather. The compounds were collected by means of diffusive samplers from August-November 2010 and February-August 2011. Carbonyl compounds, VOCs and O3 were analysed by HPLC with diode array UV-Vis detector, GC-FID and by UV-visible spectrophotometry, respectively. The most abundant carbonyls were hexanal, acetone-acrolein, formaldehyde and acetaldehyde. Seasonal variation was apparent with maximum values observed in summer months. Total carbonyl concentrations ranged from 2.8 to 19.7 μg m-3. Most VOCs studied (using chemically desorbable cartridges) were either not detected or were below their detection limits, however, a parallel sampling using thermally desorbable cartridges, from May 22 to June 19, revealed the presence of much more VOCs, identified using GC-MS. O3 concentration ranged from 27.2 to 90.5 μg m-3, reaching the maximum monthly mean concentration in March (84.4 μg m-3). The analysis of back trajectories indicates the transport of polluted air masses from remote areas, mainly from the Mediterranean basin that should contribute to the high levels of ozone observed.

  16. Spatial/temporal variations and source apportionment of VOCs monitored at community scale in an urban area.

    Science.gov (United States)

    Yu, Chang Ho; Zhu, Xianlei; Fan, Zhi-hua

    2014-01-01

    This study aimed to characterize spatial/temporal variations of ambient volatile organic compounds (VOCs) using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile) sites in Paterson and one background site in Chester, NJ (located ∼58 km southwest of Paterson). Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene) were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (pp-xylene, o-xylene, and p-dichlorobenzene measured at the commercial site were significantly higher than the industrial/mobile sites (pp-dichlorobenzene) were significantly different by season (pp<0.05). These results are consistent with literature data, indicating the impact of anthropogenic VOC sources on air pollution in Paterson. Positive Matrix Factorization (PMF) analysis was applied for 24-hour integrated VOC measurements in Paterson over one year and identified six contributing factors, including motor vehicle exhausts (20%), solvents uses (19%), industrial emissions (16%), mobile+stationery sources (12%), small shop emissions (11%), and others (22%). Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in Paterson. The study demonstrated the community-scale monitoring approach can capture spatial variation of VOCs in an urban community with mixed VOC sources. It also provided robust data to identify major sources of concern in the community.

  17. Biofiltration for control of volatile organic compounds (VOCS)

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, D.F. [Environmental Protection Agency, Cincinnati, OH (United States); Govind, R. [Univ. of Cincinnati, OH (United States)

    1995-10-01

    Air biofiltration is a promising technology for control of air emissions of biodegradable volatile organic compounds (VOCs). In conjunction with vacuum extraction of soils or air stripping of ground water, it can be used to mineralize VOCs removed from contaminated soil or groundwater. The literature describes three major biological systems for treating contaminated air bioscrubbers, biotrickling filters and biofilters. Filter media can be classified as: bioactive fine or irregular particulates, such as soil, peat, compost or mixtures of these materials; pelletized, which are randomly packed in a bed; and structured, such as monoliths with defined or variable passage size and geometry. The media can be made of sorbing and non-absorbing materials. Non-bioactive pelletized and structured media require recycled solutions of nutrients and buffer for efficient microbial activity and are thus called biotrickling filters. Extensive work has been conducted to improve biofiltration by EPA`s Risk Reduction Engineering Laboratory and the University of Cincinnati in biofilters using pelletized and structured media and improved operational approaches. Representative VOCs in these studies included compounds with a range of aqueous solubilities and octanol-water partition coefficients. The compounds include iso-pentane, toluene, methylene chloride, trichloroethylene (TCE), ethyl benzene, chlorobenzene and perchloroethylene (PCE) and alpha ({alpha}-) pinene. Comparative studies were conducted with peat/compost biofilters using isopentane and {alpha}-pinene. Control studies were also conducted to investigate adsorption/desorption of contaminants on various media using mercuric chloride solution to insure the absence of bioactivity.

  18. Toluene Diisocyanates (TDI) Action Plan

    Science.gov (United States)

    This Action Plan addresses the use of toluene diisocyanate (TDI) and related compounds in products that may result in consumer and general population exposures, particularly in or around buildings, including homes and schools.

  19. VOC emission from oil refinery and petrochemical wastewater treatment plant estimation

    Directory of Open Access Journals (Sweden)

    Mihajlović Marina A.

    2013-01-01

    Full Text Available The introduction of environmental legislation improvement for industrial producers in Serbia, notably the Integrated Pollution Prevention Control (IPPC license, will oblige the industrial producers to provide annual report on the pollutant emissions into the environment, as well as to pay certain environment fee. Wastewater treatment plant can be a significant source of volatile organic compounds (VOCs diffuse emissions, which are difficult to measure directly. In the near future reporting obligations might expend to benzene and other VOCs. This paper deals with gaseous emissions calculations from API separator based on the emission factors and the adequate software applications. The analyzed results show that the estimated emission values differ depending on the applied method. The VOC emissions have been estimated using US EPA and CONCAWE emissions factors. The calculated emissions range from 40 to 4500 tons/year for oil refinery WWTP of 2,000,000 m3/year. The calculations of benzene and toluene emissions have been performed using three methods: US EPA emission factors, WATER9, and Toxchem+ software. The calculated benzene and toluene emissions range from 5.5-60 and 0.7-20 tons/year, respectively. The highest emission values were obtained by the US EPA emission factors, while the lowest values were the result of Toxchem+ analysis. The sensitivity analysis of obtained results included the following parameters: flow, temperature, oil content, and the concentration of benzene and toluene in the effluent. Wide range of results indicates the need for their official interpretation for the conditions typical for Serbia, thus establishing adequate national emission factors for future utilization of the “polluter pays principle” on the VOC and benzene emissions.

  20. Health assessment of toluene in California drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Reed, N.; Reed, W.; Beltran, L.; Li, R.; Encomienda, I.

    1989-03-08

    This report reviews existing literature pertinent to the health risk posed by the use of toluene-contaminated drinking water. Also included in the study is an estimate of the toluene exposure of California residents based on the most recent data on toluene concentrations in California drinking water supplies. The concentration of toluene in drinking water that may cause adverse health effects is delineated.

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

    Science.gov (United States)

    Kaser, L.; Karl, T.; Schnitzhofer, R.; Graus, M.; Herdlinger-Blatt, I. S.; DiGangi, J. P.; Sive, B.; Turnipseed, A.; Hornbrook, R. S.; Zheng, W.; Flocke, F. M.; Guenther, A.; Keutsch, F. N.; Apel, E.; Hansel, A.

    2013-03-01

    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, and

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

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2012-10-01

    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

  3. 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

  4. Biofiltration of air contaminated with methanol and toluene

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2005-12-01

    Full Text Available Biofiltration of air contaminated with VOCs is inexpensive compared with the conventional techniques and very effective for treating large volumes of moist air streams with low concentrations of VOCs. In this study, biofiltration for the purification of polluted air from methanol, a hydrophilic VOC, and toluene, a hydrophobic VOC, was investigated. The experiments were operated using three separated stainless steel biofilters, for methanol, toluene, and a mixture of methanol and toluene, respectively. Biofilter consisted of a mixture of palm shells and activated sludge as a filter-bed material. Only the indigenous microorganisms of the bed medium without any addition of extra inoculum were used throughout the whole process. The polluted air inlet concentration was varied from 0.3-4.7 g/m3 with flow rates ranging from 0.06-0.45 m3/h, equivalent to the empty bed residence times of 9-71 sec. Polluted air was successfully treated by biofiltration, 100% removal efficiencies would be obtained when the air flow rate was lower than 0.45 m3/h. The presence of toluene did not affect the removal rate of methanol while the removal rate of toluene was decreased with the presence of methanol in air stream according to the competition phenomenon.

  5. VOCs Speciation From Steam Boiler Stacks of Industries Located in Naucalpan

    Science.gov (United States)

    Mejia, G. M.; Tejeda, D. D.; Bremauntz, M. P.; Valdez, A.; Montufar, P. C.; Martinez, M. A.; Sierra, M. J.; Gonzalez, C. A.

    2007-05-01

    Results of VOCs speciation from industrial steam boiler stacks located in Naucalpan are presented and discussed. This municipality is located north of the Metropolitan Zone of the Valley of Mexico (MZVM). Speciation of VOCs is important to generate information about sources of pollution, to update emission inventories, to study the dynamics of pollutants in the atmosphere, and to estimate possible risks of population exposure. This information is valuable for decision making on air pollution control strategies. Samples from 35 steam boilers form industries burning Diesel, LPG, or CNG were taken using the US-EPA Method 18. Selected samples from the use of different fuels were analyzed using gas chromatography and flame ionization detection (GC-FID) according to US-EPA protocol TO-14. The VOCs analyzed included alkanes of 9 carbons or less, alkenes of 7 carbons or less and aromatics (families of benzene). The results show consistency on the VOCs detected on Diesel samples. The main compounds found were 1- Butene+iButylene, m/p-Xylene, Ethane, Propene, Propane, Acetylene, 2Me-1Butene, and Toluene. The average concentrations of these compounds were in the range of 130 to 385 ppbC. The results of LPG samples did not show a definite pattern of VOCs, although light components predominate and, in some samples, Toluene and Xylene. These last components were not expected for industries reporting the use of LPG, perhaps due to the use of a combination of fuels and mistakes in the reports of fuel used at the time of sampling. The analysis of CNG samples show predominance of light VOCs, in the range of 90 to 300 ppbC. As in the case of LPG, some aromatics showed high concentrations in some samples analyzed perhaps due to the use of different fuels in the boiler. The results of this study are the first results of VOCs speciation obtained form exhaust gases from stacks of Mexican industries. The data reported are valuable to analyze emission inventories of VOCs and to better

  6. Characterizing the chemical evolution of air masses via multi-platform measurements of volatile organic compounds (VOCs) during CalNEX: Composition, OH reactivity, and potential SOA formation

    Science.gov (United States)

    Gilman, J. B.; Kuster, W. C.; Bon, D.; Warneke, C.; Lerner, B. M.; Williams, E. J.; Holloway, J. S.; Pollack, I. B.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Herndon, S. C.; Zahniser, M. S.; Vlasenko, A. L.; Li, S.; Alvarez, S. L.; Rappenglueck, B.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; De Gouw, J. A.

    2011-12-01

    Volatile organic compounds (VOCs) are critical components in the photochemical production of ozone (O3) and secondary organic aerosol (SOA). During the CalNex 2010 field campaign, an extensive set of VOCs were measured at the Pasadena ground site, and aboard the NOAA WP-3D aircraft and the WHOI Research Vessel Atlantis. The measurements from each platform provide a unique perspective into the emissions, transport, and atmospheric processing of VOCs within the South Coast Air Basin (SoCAB). The observed enhancement ratios of the hydrocarbons measured on all three platforms are in good agreement and are generally well correlated with carbon monoxide (CO), indicating the prevalence of on-road VOC emission sources throughout the SoCAB. Offshore measurements aboard the ship and aircraft are used to characterize the air mass composition as a function of the land/sea-breeze effect. VOC ratios and other trace gases are used to identify air masses containing relatively fresh emissions that were often associated with offshore flow and re-circulated continental air associated with onshore flow conditions. With the prevailing southwesterly airflow pattern in the LAB throughout the daytime, the Pasadena ground site effectively functions as a receptor site and is used to characterize primary VOC emissions from downtown Los Angeles and to identify the corresponding secondary oxidation products. The chemical evolution of air masses as a function of the time of day is investigated in order to determine the relative impacts of primary emissions vs. secondary VOC products on OH reactivity and potential SOA formation. The reactivity of VOCs with the hydroxyl radical (OH) at the Pasadena site was dominated by the light hydrocarbons, isoprene, and oxygenated VOCs including aldehydes (secondary products) and alcohols (primary anthropogenic emissions). Toluene and benzaldehyde, both of which are associated with primary anthropogenic emissions, are the predominant VOC precursors to the

  7. Determination of VOC emission rates and compositions for offset printing.

    Science.gov (United States)

    Wadden, R A; Scheff, P A; Franke, J E; Conroy, L M; Keil, C B

    1995-07-01

    The release rates of volatile organic compounds (VOC) as fugitive emissions from offset printing are difficult to quantify, and the compositions are usually not known. Tests were conducted at three offset printing shops that varied in size and by process. In each case, the building shell served as the test "enclosure," and air flow and concentration measurements were made at each air entry and exit point. Emission rates and VOC composition were determined during production for (1) a small shop containing three sheetfed presses and two spirit duplicators (36,700 sheets, 47,240 envelopes and letterheads), (2) a medium-size industrial in-house shop with two webfed and three sheetfed presses, and one spirit duplicator (315,130 total sheets), and (3) one print room of a large commercial concern containing three webfed, heatset operations (1.16 x 10(6) ft) served by catalytic air pollution control devices. Each test consisted of 12 one-hour periods over two days. Air samples were collected simultaneously during each period at 7-14 specified locations within each space. The samples were analyzed by gas chromatography (GC) for total VOC and for 13-19 individual organics. Samples of solvents used at each shop were also analyzed by GC. Average VOC emission rates were 4.7-6.1 kg/day for the small sheetfed printing shop, 0.4-0.9 kg/day for the industrial shop, and 79-82 kg/day for the commercial print room. Emission compositions were similar and included benzene, toluene, xylenes, ethylbenzene, and hexane. Comparison of the emission rates with mass balance estimates based on solvent usage and composition were quite consistent.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Volatile organic compounds (VOCs) in surface coating materials: Their compositions and potential as an alternative fuel.

    Science.gov (United States)

    Dinh, Trieu-Vuong; Choi, In-Young; Son, Youn-Suk; Song, Kyu-Yong; Sunwoo, Young; Kim, Jo-Chun

    2016-03-01

    A sampling system was designed to determine the composition ratios of VOCs emitted from 31 surface coating materials (SCMs). Representative architectural, automotive, and marine SCMs in Korea were investigated. Toluene, ethylbenzene, and xylene were the predominant VOCs. The VOC levels (wt%) from automotive SCMs were significantly higher than those from architectural and marine paints. It was found that target SCMs comprised mainly VOCs with 6-10 carbon atoms in molecules, which could be adsorbed by activated carbon. The saturated activated carbon which had already adsorbed toluene, ethylbenzene, and m-xylene was combusted. The saturated activated carbon was more combustible than new activated carbon because it comprised inflammable VOCs. Therefore, it could be an alternative fuel when using in a "fuelization system". To use the activated carbon as a fuel, a control technology of VOCs from a coating process was also designed and introduced.

  9. DEVELOPMENT OF AEROBIC BIOFILTER DESIGN CRITERIA FOR TREATING VOCS

    Science.gov (United States)

    This paper reports preliminary results on the use of trickle bed biofilters with monolithic ceramic channelized microbial support structures for the treatment of VOCs typical of landfill leachate stripping. Toluene was used for the purpose of characterizing the trickle bed biofi...

  10. DEVELOPMENT OF AEROBIC BIOFILTER DESIGN CRITERIA FOR TREATING VOCS

    Science.gov (United States)

    This paper reports preliminary results on the use of trickle bed biofilters with monolithic ceramic channelized microbial support structures for the treatment of VOCs typical of landfill leachate stripping. Toluene was used for the purpose of characterizing the trickle bed biofi...

  11. Experimental Study on the Absorption of Toluene from Exhaust Gas by Paraffin/Surfactant/Water Emulsion

    OpenAIRE

    Ping Fang; Zi-jun Tang; Xiong-bo Chen; Zhi-xiong Tang; Ding-sheng Chen; Jian-hang Huang; Wen-hao Zeng; Chao-ping Cen

    2016-01-01

    A new paraffin/surfactant/water emulsion (PSW) for volatile organic compounds (VOCs) controlling was prepared and its potential for VOCs removal was investigated. Results indicated that PSW-5 (5%, v/v) provided higher toluene absorption efficiency (90.77%) than the other absorbents used. The saturation pressure, Henry’s constant, and activity coefficient of toluene in PSW-5 were significantly lower than those in water, and toluene solubility (1.331 g·L−1) in the PSW-5 was more than 2.5 times ...

  12. Kinetics and simulations of substrate interactions during the biodegradation of benzene, toluene, p-xylene and styrene.

    Science.gov (United States)

    Song, Jihyeon; Shin, Seungkyu; Jang, Hyun-Sup; Hwang, Sun-Jin

    2012-01-01

    Air streams commonly emitted from industrial sources generally contain various mixtures of volatile organic compounds (VOCs), and these complex mixtures can present challenges with respect to bioreactor design and applications. In this study, therefore, a modified Monod-type model using interaction parameters was employed to describe the biodegradation kinetics of mixtures of aromatic compounds by a Pseudomonas isolate. In addition, the model and estimated parameters were utilized to predict the performance of a bubble-column bioreactor for the treatment of mixtures of benzene, toluene, p-xylene, and styrene (BTXS). Benzene, toluene and styrene, as individual substrates, were actively degraded by the bacterial culture, whereas p-xylene was not degraded as a single substrate. Relative to the single substrate experiments, the degradation of benzene and toluene was inhibited by the other compounds, while the degradation of styrene was significantly stimulated in the presence of the other BTXS compounds. The cometabolic degradation of p-xylene was observed in the presence of benzene and toluene. The estimated interaction parameters indicated that the degradation of benzene was substantially inhibited in the presence of styrene, whereas the degradation of styrene was strongly stimulated by toluene. The kinetic coefficients and interaction parameters were used to successfully predict the biodegradation kinetics and performance of a bioreactor subjected to the quaternary mixture. Overall, the model was able to provide reasonable predictions when substrate interactions, including inhibition, stimulation, and cometabolism, play significant roles in biodegradation processes.

  13. 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

  14. Experimental Study on the Absorption of Toluene from Exhaust Gas by Paraffin/Surfactant/Water Emulsion

    Directory of Open Access Journals (Sweden)

    Ping Fang

    2016-01-01

    Full Text Available A new paraffin/surfactant/water emulsion (PSW for volatile organic compounds (VOCs controlling was prepared and its potential for VOCs removal was investigated. Results indicated that PSW-5 (5%, v/v provided higher toluene absorption efficiency (90.77% than the other absorbents used. The saturation pressure, Henry’s constant, and activity coefficient of toluene in PSW-5 were significantly lower than those in water, and toluene solubility (1.331 g·L−1 in the PSW-5 was more than 2.5 times higher than the value in water. Several factors potentially affecting the toluene absorption efficiency were systematically investigated. The results suggested that concentration and pH of PSW, absorption temperature, and gas flow rate all had a strong influence on the toluene absorption, but the inlet concentration of toluene had little effect on the toluene absorption. There were different absorbing performances of PSW-5 on different VOCs, and the ketones, esters, and aromatics were more easily removed by the PSW-5 than the alkanes. Regeneration and reuse of the PSW were possible; after 3 runs of regeneration the absorption efficiency of PSW-5 for toluene also could reach 82.42%. So, the PSW is an economic, efficient, and safe absorbent and has a great prospect in organic waste gas treatment.

  15. Toluene emissions from plants

    Science.gov (United States)

    Heiden, A. C.; Kobel, K.; Komenda, M.; Koppmann, R.; Shao, M.; Wildt, J.

    The emission of toluene from different plants was observed in continuously stirred tank reactors and in field measurements. For plants growing without stress, emission rates were low and ranged from the detection limit up to 2·10-16 mol·cm-2·s-1. Under conditions of stress, the emission rates exceeded 10-14 mol·cm-2·s-1. Exposure of sunflower (Helianthus annuus L. cv. Gigantheus) to 13CO2 resulted in 13C-labeling of the emitted toluene on a time scale of hours. Although no biochemical pathway for the production of toluene is known, these results indicate that toluene is synthesized by the plants. The emission rates of toluene from sunflower are dependent on nutrient supply and wounding. Since α-pinene emission rates are also influenced by these factors, toluene and α-pinene emissions show a high correlation. During pathogen attack on Scots pines (Pinus sylvestris L.) significant toluene emissions were observed. In this case emissions of toluene and α-pinene also show a good correlation. Toluene emissions were also found in field experiments with pines using branch enclosures.

  16. 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,...

  17. World Calibration Center for VOC (WCC-VOC), a new Facility for the WMO-GAW-Programme

    Science.gov (United States)

    Rappenglueck, B.-

    2002-12-01

    Volatile organic compounds (VOC) are recognized to be important precursors of tropospheric ozone as well as other oxidants and organic aerosols. In order to design effective control measures for the reduction of photooxidants, photochemical processes have to be understood and the sources of the precursors known. Reliable and representative measurements of VOCs are necessary to describe the anthropogenic and biogenic sources, to follow the photochemical degradation of VOCs in the troposphere. Measurement of VOCs is of key importance for the understanding of tropospheric chemistry. Tropospheric VOCs have been one of the recommended measurements to be made within the GAW programme. The purpose will be to monitor their atmospheric abundance, to characterize the various compounds with regard to anthropogenic and biogenic sources and to evaluate their role in the tropospheric ozone formation process. An international WMO/GAW panel of experts for VOC measurements developed the rational and objectives for this GAW activity and recommended the configuration and required activities of the WCC-VOC. In reflection of the complexity of VOC measurements and the current status of measurement technology, a "staged" approach was adopted. Stage 1 measurements: C2-C9 hydrocarbons, including alkanes, alkenes, alkynes, dienes and monocyclics. (The WCC-VOC operates currently under this mode). Stage 2 measurements: C10-C14 hydrocarbons, including higher homologs of the Stage 1 set as well as biogenic hydrocarbon compounds. Stage 3 measurements: Oxygenated VOCs, including alcohols, carbonyls, carboxylic acids. The Quality Assurance/Science Activity Centre (QA/SAC) Germany currently has established the World Calibration Centre for VOC (WCC-VOC). The WCC-VOC has operated in the research mode und has become operational recently. From now on, the WCC-VOC conducts one round-robin calibration audit per year at all global stations that measure VOCs and assists other stations in setting up VOC

  18. T2VOC user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Falta, R.W. [Clemson Univ., Clemson, SC (United States). Dept. of Earth Sciences; Pruess, K.; Finsterle, S. [Lawrence Berkeley Lab., CA (United States); Battistelli, A. [AQUATER S.p.A., San Lorenzo in Campo, (Italy)

    1995-03-01

    T2VOC is a numerical simulator for three-phase, three-component, non-isothermal flow of water, air, and a volatile organic compound (VOC) in multidimensional heterogeneous porous media. Developed at the Lawrence Berkeley Laboratory, T2VOC is an extension of the TOUGH2 general-purpose simulation program. This report is a self-contained guide to application of T2VOC to subsurface contamination problems involving nonaqueous phase liquids (NAPLs). It gives a technical description of the T2VOC code, including a discussion of the physical processes modeled, and the mathematical and numerical methods used. Detailed instructions for preparing input data are presented along with several illustrative sample problems.

  19. VOC transport in vented drums containing simulated waste sludge

    Energy Technology Data Exchange (ETDEWEB)

    Liekhus, K.J.; Gresham, G.L.; Rae, C.; Connolly, M.J.

    1994-02-01

    A model is developed to estimate the volatile organic compound (VOC) concentration in the headspace of the innermost layer of confinement in a lab-scale vented waste drum containing simulated waste sludge. The VOC transport model estimates the concentration using the measured VOC concentration beneath the drum lid and model parameters defined or estimated from process knowledge of drum contents and waste drum configuration. Model parameters include the VOC diffusion characteristic across the filter vent, VOC diffusivity in air, size of opening in the drum liner lid, the type and number of layers of polymer bags surrounding the waste, VOC permeability across the polymer, and the permeable surface area of the polymer bags. Comparison of model and experimental results indicates that the model can accurately estimate VOC concentration in the headspace of the innermost layer of confinement. The model may be useful in estimating the VOC concentration in actual waste drums.

  20. Indoor contaminants from Hardcopy Devices: Characteristics of VOCs in photocopy centers

    Science.gov (United States)

    Sarkhosh, Maryam; Mahvi, Amir Hossein; Zare, Mohammad Reza; Fakhri, Yadolah; Shamsolahi, Hamid Reza

    2012-12-01

    Indoor air pollution in working places is widely recognized as one of the most serious potential environment risks to human health. Mean volatile organic compound (VOC) concentrations of 144 samples from four copy centers in Tehran, Iran in two seasons were monitored for the purpose of quantifying the various VOCs in these areas. Area samples were collected in thermal desorption tubes and were analyzed using gas chromatography/mass selective detector. Real-time personal total volatile organic compounds were measured using a data-logging photo-ionization detector. Simultaneously, BTEX (benzene, toluene, ethylbenzene, xylenes) outdoor measurements were performed in the same manner as were the indoor measurements. Nineteen different VOCs were detected in the area samples. The results show that in all photocopy centers, the indoor levels of toluene were much higher than the outdoor levels. During business hours, the VOC levels increased, especially toluene indoor concentration. The ventilation decreased the indoor VOC concentrations. The background and indoor VOC concentrations were higher in winter than in spring. The minimum ratio of the indoor to outdoor concentration of BTEX was estimated to be more than 42. This value proved that buildings with photocopiers can be a site of VOC accumulation.

  1. Removal of gaseous toluene by the combination of photocatalytic oxidation under complex light irradiation of UV and visible light and biological process.

    Science.gov (United States)

    Wei, Zaishan; Sun, Jianliang; Xie, Zhirong; Liang, Mingyan; Chen, Shangzhi

    2010-05-15

    Photocatalysis is a promising technology for treatment of gaseous waste; its disadvantages, however, include causing secondary pollution. Biofiltration has been known as an efficient technology for treatment volatile organic compounds (VOCs) at low cost of maintenance, and produces harmless by-products; its disadvantages, include large volume of bioreactor and slow adaptation to fluctuating concentrations in waste gas. A bench scale system integrated with a photocatalytic oxidation and a biofilter unit for the treatment of gases containing toluene was investigated. The integrated system can effectively oxidize toluene with high removal efficiency. The photocatalytic activity of N-TiO(2)/zeolite was evaluated by the decomposition of toluene in air under UV and visible light (VL) illumination. The N-TiO(2)/zeolite has more photocatalytic activity under complex light irradiation of UV and visible light for toluene removal than that of pure TiO(2)/zeolite under UV or visible light irradiation. N-TiO(2)/zeolite was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS), Fourier transform infrared spectroscopy (FT-IR), and as-obtained products were identified by means of gas chromatography/mass spectrometry (GC/MS). Results revealed that the photocatalyst was porous and was high photoactive for mineralizing toluene. The high activity can be attributed to the results of the synergetic effects of strong UV and visible light absorption, surface hydroxyl groups. The photocatalytic degradation reaction of toluene with the N-TiO(2)/zeolite follows Langmuir-Hinshelwood kinetics. Toluene biodegradation rate matches enzymatic oxidation kinetics model. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  2. Removal of gaseous toluene by the combination of photocatalytic oxidation under complex light irradiation of UV and visible light and biological process

    Energy Technology Data Exchange (ETDEWEB)

    Wei Zaishan, E-mail: weizaishan98@163.com [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Sun Jianliang; Xie Zhirong; Liang Mingyan; Chen Shangzhi [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2010-05-15

    Photocatalysis is a promising technology for treatment of gaseous waste; its disadvantages, however, include causing secondary pollution. Biofiltration has been known as an efficient technology for treatment volatile organic compounds (VOCs) at low cost of maintenance, and produces harmless by-products; its disadvantages, include large volume of bioreactor and slow adaptation to fluctuating concentrations in waste gas. A bench scale system integrated with a photocatalytic oxidation and a biofilter unit for the treatment of gases containing toluene was investigated. The integrated system can effectively oxidize toluene with high removal efficiency. The photocatalytic activity of N-TiO{sub 2}/zeolite was evaluated by the decomposition of toluene in air under UV and visible light (VL) illumination. The N-TiO{sub 2}/zeolite has more photocatalytic activity under complex light irradiation of UV and visible light for toluene removal than that of pure TiO{sub 2}/zeolite under UV or visible light irradiation. N-TiO{sub 2}/zeolite was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS), Fourier transform infrared spectroscopy (FT-IR), and as-obtained products were identified by means of gas chromatography/mass spectrometry (GC/MS). Results revealed that the photocatalyst was porous and was high photoactive for mineralizing toluene. The high activity can be attributed to the results of the synergetic effects of strong UV and visible light absorption, surface hydroxyl groups. The photocatalytic degradation reaction of toluene with the N-TiO{sub 2}/zeolite follows Langmuir-Hinshelwood kinetics. Toluene biodegradation rate matches enzymatic oxidation kinetics model.

  3. Photoelectron Imaging of OXIDE.VOC Clusters

    Science.gov (United States)

    Patros, Kellyn M.; Mann, Jennifer; Chick Jarrold, Caroline

    2016-06-01

    Perturbations of the bare O2- and O4- electronic structure arising from VOC (VOC = hexane, isoprene, benzene and benzene.D6) interactions are investigated using anion photoelectron imaging at 2.33 and 3.49 eV photon energies. Trends observed from comparing features in the spectra include VOC-identity-dependent electron affinities of the VOC complexes relative to the bare oxide clusters, due to enhance stability in the anion complex relative to the neutral. Autodetachment is observed in all O4-.VOC spectra and only isoprene with O2-. In addition, the intensities of transitions to states correlated with the singlet states of O2 neutral via detachment from the O2-.VOC anion complexes show dramatic VOC-identity variations. Most notably, benzene as a complex partner significantly enhances these transitions relative to O2- and O2-.hexane. A less significant enhancement is also observed in the O2-.isoprene complex. This enhancement may be due to the presence of low-lying triplet states in the complex partners.

  4. Treatment of mixtures of toluene and n-propanol vapours in a compost-woodchip-based biofilter.

    Science.gov (United States)

    Dixit, R M; Deshmukh, S C; Gadhe, A A; Kannade, G S; Lokhande, S K; Pandey, R A; Vaidya, A N; Mudliar, S N; Deshusses, M A

    2012-01-01

    The present work describes the biofiltration of mixture of n-propanol (as a model hydrophilic volatile organic compound (VOC)) and toluene (as a model hydrophobic VOC) in a biofilter packed with a compost-woodchip mixture. Initially, the biofilter was fed with toluene vapours at loadings up to 175 g m(-3) h(-1) and removal efficiencies of 70%-99% were observed. The biofilter performance when removing mixtures of toluene and n-propanol reached elimination capacities of up to 67g(toluene) m(-3) h(-1) and 85 g(n-propanol) m(-3) h(-1) with removal efficiencies of 70%-100% for toluene and essentially 100% for n-propanol. The presence of high n-propanol loading negatively affected the toluene removal; however, n-propanol removal was not affected by the presence of toluene and was effectively removed in the biofilter despite high toluene loadings. A model for toluene and n-propanol biofiltration could predict the cross-inhibition effect of n-propanol on toluene removal.

  5. A demonstration of biofiltration for VOC removal in petrochemical industries.

    Science.gov (United States)

    Zhao, Lan; Huang, Shaobin; Wei, Zongmin

    2014-05-01

    A biotrickling filter demo has been set up in a petrochemical factory in Sinopec Group for about 10 months with a maximum inlet gas flow rate of 3000 m3 h(-1). The purpose of this project is to assess the ability of the biotrickling filter to remove hardly biodegradable VOCs such as benzene, toluene and xylene which are recalcitrant and poorly water soluble and commonly found in petrochemical factories. Light-weight hollow ceramic balls (Φ 5-8 cm) were used as the packing media treated with large amounts of circulating water (2.4 m3 m(-2) h(-1)) added with bacterial species. The controlled empty bed retention time (EBRT) of 240 s is a key parameter for reaching a removal efficiency of 95% for benzene, toluene, xylene, and 90% for total hydrocarbons. The demo has been successfully adopted and practically applied in waste air treatments in many petrochemical industries for about two years. The net inlet concentrations of benzene, toluene and xylene were varied from 0.5 to 3 g m(-3). The biofiltration process is highly efficient for the removal of hydrophobic and recalcitrant VOCs with various concentrations from the petrochemical factories. The SEM analysis of the bacterial community in the BTF during VOC removal showed that Pseudomonas putida and Klebsiella sp. phylum were dominant and shutdown periods could play a role in forming the community structural differences and leading to the changes of removal efficiencies.

  6. Measurement of VOCs in vehicle exhaust by extractive FTIR spectroscopy

    Science.gov (United States)

    Lechner, Bernhard; Paar, H.; Sturm, Peter J.

    2001-02-01

    12 The detection of benzene and other organic compounds in vehicle exhaust by FT-IR-spectroscopy is seriously limited by the strong interference of carbon dioxide and the rather weak absorption coefficient of the gases. Therefore, a measurement device was developed which separates the components of interest (mostly VOCs) from carbon dioxide, water and nitric oxide. In addition the VOCs have to be pre- concentrated. To avoid condensation of VOCs the measurements have to take place at higher temperatures. The vehicle exhaust was led through an activated charcoal tube where the organic compounds were adsorbed. Afterwards, the charcoal tube was heated in a furnace, the VOCs were desorbed thermically and were carried by (heated) nitrogen into a gas cell with a path-length of 10 m where the concentration of the different species was measured. With the help of this measurement device a lot of VOC- components like benzene, toluene, and xylene were detected successfully. Measurements were performed on an engine test bed and a chassis dynamometer for heavy duty vehicles. The detection limit of most of the VOCs was about 2 to 3 ppb for a sampling time of 20 min. Calibration measurements showed an accuracy of 15%.

  7. 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, NOx, CO, PM10, PM2.5, 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, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx 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.

  8. 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.

  9. 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.

  10. Development of a portable instrument for the continuous analysis of volatile organic compounds (VOCs) and its application to environmental monitoring.

    Science.gov (United States)

    Yamada, Etsu; Matsushita, Kazumasa; Nakamura, Mitsuaki; Fuse, Yasuro; Miki, Sadao; Fujimoto, Kiyoomi; Morita, Hiroyoshi; Shimada, Osamu

    2006-01-01

    A small, time efficient and sensitive instrument for the continuous analysis of very volatile organic compounds (VOCs) with a boiling point lower than 100 degrees C in addition to the analysis of VOCs with a boiling point in the range of 100-150 degrees C was developed and applied to the measurement of VOCs in the course of university research and environmental monitoring. VOCs, such as n-hexane, acetone, ethyl acetate, alcohols, benzene, toluene and xylene, were continuously measured once every 30 min. The detection limits of hexane, ethyl acetate, benzene and toluene at a preconcentration time of 10 min were 0.41 microg/m(3) (0.12 ppb), 0.67 microg/m(3) (0.19 ppb), 0.22 microg/m(3) (0.07 ppb) and 0.22 microg/m(3) (0.06 ppb), respectively. The relative standard deviations of VOCs were less than 5%. The sensitivities of the present method VOCs were higher than those of the conventional method. The temporal changes in VOC concentrations in several laboratories and at a plant for the disposal of organic liquid wastes were measured, and the behavior of VOCs was analyzed. All the VOC concentrations, except that of ethyl acetate, determined using the portable instrument were slightly lower than those determined using a passive sampler. The portable instrument developed in the course of this study can be used for the risk assessment and management of chemicals.

  11. Exposure of jeepney drivers in Manila, Philippines, to selected volatile organic compounds (VOCs).

    Science.gov (United States)

    Balanay, Jo Anne G; Lungu, Claudiu T

    2009-01-01

    The objective of this study was to assess the occupational exposure of jeepney drivers to selected volatile organic compounds (VOCs) in Manila, Philippines. Personal sampling was conducted on 15 jeepney drivers. Area sampling was conducted to determine the background VOC concentration in Manila as compared to that in a rural area. Both personal and area samples were collected for 5 working days. Samples were obtained using diffusive samplers and were analyzed for 6 VOCs (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) using gas chromatography. Results showed that the average personal exposure concentration of jeepney drivers was 55.6 (+/-9.3), 196.6 (+/-75.0), 17.9 (+/-9.0), 72.5 (+/-21.1) and 88.5 (+/-26.5) microg/m(3) for benzene, toluene, ethylbenzene, m,p-xylene and o-xylene, respectively. The urban ambient concentration was 11.8 (+/-2.2), 83.7 (+/-40.5) and 38.0 (+/-12.1) microg/m(3) for benzene, toluene and o-xylene, respectively. The rural ambient concentration was 14.0 (+/-6.0) and 24.7 (+/-11.9) microg/m(3) for toluene and o-xylene, respectively. The personal samples had significantly higher (pp<0.05) than the rural concentrations. The personal exposures for all the target VOCs were not significantly different among the jeepney drivers.

  12. 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.

  13. 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.

  14. 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.

  15. Volatile Organic Compound (VOC) Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up.

    Science.gov (United States)

    Rebollar-Perez, Georgette; Carretier, Emilie; Lesage, Nicolas; Moulin, Philippe

    2011-03-03

    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.

  16. Photocatalytic Solar Tower Reactor for the Elimination of a Low Concentration of VOCs

    Directory of Open Access Journals (Sweden)

    Nobuaki Negishi

    2014-10-01

    Full Text Available We developed a photocatalytic solar tower reactor for the elimination of low concentrations of volatile organic compounds (VOCs typically emitted from small industrial establishments. The photocatalytic system can be installed in a narrow space, as the reactor is cylindrical-shaped. The photocatalytic reactor was placed vertically in the center of a cylindrical scattering mirror, and this vertical reactor was irradiated with scattered sunlight generated by the scattering mirror. About 5 ppm toluene vapor, used as representative VOC, was continuously photodegraded and converted to CO2 almost stoichiometrically under sunny conditions. Toluene removal depended only on the intensity of sunlight. The performance of the solar tower reactor did not decrease with half a year of operation, and the average toluene removal was 36% within this period.

  17. Photocatalytic solar tower reactor for the elimination of a low concentration of VOCs.

    Science.gov (United States)

    Negishi, Nobuaki; Sano, Taizo

    2014-01-01

    We developed a photocatalytic solar tower reactor for the elimination of low concentrations of volatile organic compounds (VOCs) typically emitted from small industrial establishments. The photocatalytic system can be installed in a narrow space, as the reactor is cylindrical-shaped. The photocatalytic reactor was placed vertically in the center of a cylindrical scattering mirror, and this vertical reactor was irradiated with scattered sunlight generated by the scattering mirror. About 5 ppm toluene vapor, used as representative VOC, was continuously photodegraded and converted to CO2 almost stoichiometrically under sunny conditions. Toluene removal depended only on the intensity of sunlight. The performance of the solar tower reactor did not decrease with half a year of operation, and the average toluene removal was 36% within this period.

  18. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    Directory of Open Access Journals (Sweden)

    Roumporn Nikom

    2006-11-01

    Full Text Available Toluene, an important volatile organic compound (VOC, is used in many kinds of industries, such as painting, printing, coating, and petrochemical industries. The emission of toluene causes serious air pollution, odor problem, flammability problem and affects human health. This paper proposes the removal of toluene from waste air using a spray wet scrubber combining the absorption and oxidation reaction. Aqueous sodium hypochlorite (NaOCl solution was used as the scrubbing liquid in the system. NaOCl, the strongest oxidative agent, presents an effective toluene removal. As the scrubbed toluene is reacted, recirculation of the scrubbing liquid could be operated with a constant removal efficiency throughout the operting time. The investigated variables affecting the removal efficiency were air flow rate, inlet toluene concentration, NaOCl concentration, scrubbing liquid flow rate and size of spray nozzle. Influence of the scrubbing parameters was experimentally studied to develop a mathematical model of the toluene removal efficiency. The removal model reveals that the increase of scrubbing liquid flow rate, toluene concentration, and NaOCl concentration together with the decrease of air flow rate and size of spray nozzle can increase the toluene removal efficiency. Optimization problem with an objective function and constraints was set to provide the maximum toluene removal efficiency and solved by Matlab optimization toolbox. The optimization constraints were formed from the mathematical model and process limitation. The solution of the optimization was an air flow rate of 100 m3/h, toluene concentration of 1500 ppm, NaOCl concentration of 0.02 mol/l, NaOCl solution feed rate of 0.8 m3/h, and spray nozzle size of 0.5 mm. Solution of the optimization gave the highest toluene removal efficiency of 91.7%.

  19. Remove volatile organic compounds (VOCs) with membrane separation techniques

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Membrane separation, a new technology for removing VOCs including pervaporation, vapor permeation, membrane contactor, and membrane bioreactor was presented. Comparing with traditional techniques, these special techniques are an efficient and energy-saving technology. Vapor permeation can be applied to recovery of organic solvents from exhaust streams. Membrane contactor could be used for removing or recovering VOCs from air or wastewater. Pervaporation and vapor permeation are viable methods for removing VOCs from wastewater to yield a VOC concentrate which could either be destroyed by conventional means, or be recycled for reuse.

  20. VOCs in Arid soils: Technology summary

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. 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.

  2. Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants.

    Science.gov (United States)

    Sriprapat, Wararat; Suksabye, Parinda; Areephak, Sirintip; Klantup, Polawat; Waraha, Atcharaphan; Sawattan, Anuchit; Thiravetyan, Paitip

    2014-04-01

    Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plant׳s cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air.

  3. Toluene-Degrading Bacteria Are Chemotactic towards the Environmental Pollutants Benzene, Toluene, and Trichloroethylene

    Science.gov (United States)

    Parales, Rebecca E.; Ditty, Jayna L.; Harwood, Caroline S.

    2000-01-01

    The bioremediation of polluted groundwater and toxic waste sites requires that bacteria come into close physical contact with pollutants. This can be accomplished by chemotaxis. Five motile strains of bacteria that use five different pathways to degrade toluene were tested for their ability to detect and swim towards this pollutant. Three of the five strains (Pseudomonas putida F1, Ralstonia pickettii PKO1, and Burkholderia cepacia G4) were attracted to toluene. In each case, the response was dependent on induction by growth with toluene. Pseudomonas mendocina KR1 and P. putida PaW15 did not show a convincing response. The chemotactic responses of P. putida F1 to a variety of toxic aromatic hydrocarbons and chlorinated aliphatic compounds were examined. Compounds that are growth substrates for P. putida F1, including benzene and ethylbenzene, were chemoattractants. P. putida F1 was also attracted to trichloroethylene (TCE), which is not a growth substrate but is dechlorinated and detoxified by P. putida F1. Mutant strains of P. putida F1 that do not oxidize toluene were attracted to toluene, indicating that toluene itself and not a metabolite was the compound detected. The two-component response regulator pair TodS and TodT, which control expression of the toluene degradation genes in P. putida F1, were required for the response. This demonstration that soil bacteria can sense and swim towards the toxic compounds toluene, benzene, TCE, and related chemicals suggests that the introduction of chemotactic bacteria into selected polluted sites may accelerate bioremediation processes. PMID:10966434

  4. Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal.

    Science.gov (United States)

    Liu, Zhen-Shu; Peng, Yu-Hui; Li, Wen-Kai

    2014-01-01

    Few studies have investigated the use of activated carbon fibres (ACFs) impregnated with metal oxides for the catalytic oxidation of volatile organic compounds (VOCs). Thus, the effects of the ACF-supported metal oxides on toluene removal are determined in this study. Three catalysts, namely, Ce, Mn, and Cu, two pretreatment solutions NaOH and H2O2, and three reaction temperatures of 250 degrees C, 300 degrees C, and 350 degrees C, were employed to determine toluene removal. The composition and morphology of the catalysts were analysed using Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometer (FTIR), and thermo-gravimetric analyser (TGA) to study the effects of the catalyst's characteristics on toluene removal. The results demonstrated that the metal catalysts supported on the ACFs could significantly increase toluene removal. The Mn/ACFs and Cu/ACFs were observed to be most active in toluene removal at a reaction temperature of 250 degrees C with 10% oxygen content. Moreover, the data also indicated that toluene removal was slightly improved after pretreating the ACFs with NaOH and H2O2. The results suggested that surface-metal loading and the surface characteristics of the ACFs were the determinant parameters for toluene removal. Furthermore, the removal of toluene over Mn/ACFs-H202 decreased when the reaction temperature considered was > 300 degrees C.

  5. Novel Toluene Elimination System in a Toluene-Tolerant Microorganism

    Science.gov (United States)

    Kobayashi, Hideki; Uematsu, Katsuyuki; Hirayama, Hisako; Horikoshi, Koki

    2000-01-01

    In studies of Pseudomonas putida IH-2000, a toluene-tolerant microorganism, membrane vesicles (MVs) were found to be released from the outer membrane when toluene was added to the culture. These MVs were found to be composed of phospholipids, lipopolysaccharides (LPS), and very low amounts of outer membrane proteins. The MVs also contained a higher concentration of toluene molecules (0.172 ± 0.012 mol/mol of lipid) than that found in the cell membrane. In contrast to the wild-type strain, the toluene-sensitive mutant strain 32, which differs from the parent strain in LPS and outer membrane proteins, did not release MVs from the outer membrane. The toluene molecules adhering to the outer membrane are eliminated by the shedding of MVs, and this system appears to serve as an important part of the toluene tolerance system of IH-2000. PMID:11053390

  6. 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.

  7. Quantification of Methane and VOC Emissions from Natural Gas Production in Two Basins with High Ozone Events

    Science.gov (United States)

    Edie, R.; Robertson, A.; Snare, D.; Soltis, J.; Field, R. A.; Murphy, S. M.

    2015-12-01

    Since 2005, the Uintah Basin of Utah and the Upper Green River Basin of Wyoming frequently exceeded the EPA 8-hour allowable ozone level of 75 ppb, spurring interest in volatile organic compounds (VOCs) emitted during oil and gas production. Debate continues over which stage of production (drilling, flowback, normal production, transmission, etc.) is the most prevalent VOC source. In this study, we quantify emissions from normal production on well pads by using the EPA-developed Other Test Method 33a. This methodology combines ground-based measurements of fugitive emissions with 3-D wind data to calculate the methane and VOC emission fluxes from a point source. VOC fluxes are traditionally estimated by gathering a canister of air during a methane flux measurement. The methane:VOC ratio of this canister is determined at a later time in the laboratory, and applied to the known methane flux. The University of Wyoming Mobile Laboratory platform is equipped with a Picarro methane analyzer and an Ionicon Proton Transfer Reaction-Time of Flight-Mass Spectrometer, which provide real-time methane and VOC data for each well pad. This independent measurement of methane and VOCs in situ reveals multiple emission sources on one well pad, with varying methane:VOC ratios. Well pad emission estimates of methane, benzene, toluene and xylene for the two basins will be presented. The different emission source VOC profiles and the limitations of real-time and traditional VOC measurement methods will also be discussed.

  8. DESORPTION OF VOCs FROM POLYMERIC ADSORBENTS UNDER MICROWAVE FIELD

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Desorption of volatile organic compounds (VOCs)from polymeric adsorbents by microwave was investigated experimentally. Two kinds of organic compounds, benzene and toluene,were separately used as adsorbates in this work. Results showed that the application of microwave to regenerate the polymeric adsorbents not only can get higher regeneration efficiency in comparison with the use of heat regeneration, but also make the temperatures of the fixed beds much lower than that when using the heat regeneratton The weaker the polarity of a polymeric adsorbent, the easier its regeneration was.

  9. DESORPTION OF VOCs FROM POLYMERIC ADSORBENTS UNDER MICROWAVE FIELD

    Institute of Scientific and Technical Information of China (English)

    LIXiang; LIZhong; 等

    2001-01-01

    Desorption of volatile organic compounds(VOCs) from polymeric adsorbents by microwave was investigated experimentally.Two kinds of organic compounds.benzene and toluene.were separately used as adsorbates in this work Results showed that the application of microwave to regenerate the polymeric adsorbents not only can get higher regeneration efficiency in comparison with the use of heat regeneration,but also make the temperatures of the fixed beds much lower than that when using the heat regeneration the weaker the polarity of a polymericadsorbent,the easier its regeneration was.

  10. Distributions of personal VOC exposures: a population-based analysis.

    Science.gov (United States)

    Jia, Chunrong; D'Souza, Jennifer; Batterman, Stuart

    2008-10-01

    Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999--2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.

  11. A comparative study in treating two VOC mixtures in trickle bed air biofilters.

    Science.gov (United States)

    Cai, Zhangli; Kim, Daekeun; Sorial, George A

    2007-06-01

    Two independent parallel trickling bed air biofilters (TBABs) ("A" and "B") with two different typical VOC mixtures were investigated. Toluene, styrene, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK) were the target VOCs in the mixtures. Biofilter "A" was fed equal molar ratio of the VOCs and biofilter "B" was fed a mixture based on EPA 2003 emission report. Backwashing and substrate starvation operation were conducted as biomass control. Biofilter "A" and "B" maintained 99% overall removal efficiency for influent concentration up to 500 and 300 ppmv under backwashing operating condition, respectively. The starvation study indicated that it can be an effective biomass control for influent concentrations up to 250 ppmv for biofilter "A" and 300 ppmv for "B". Re-acclimation of biofilter performance was delayed with increase of influent concentration for both biofilters. Starvation operation helped the biofilter to recover at low concentrations and delayed re-acclimation at high concentrations. Furthermore, re-acclamation for biofilter "B" was delayed due to its high toluene content as compared to biofilter "A". The pseudo first-order removal rate constant decreased with increase of volumetric loading rate for both biofilters. MEK and MIBK were completely removed in the upper 3/8 media depth. While biofilter depth utilization for the removal of styrene and toluene increased with increase of influent concentrations for both biofilters. However, toluene removal utilized more biofilter depth for biofilter "B" as compared to biofilter "A".

  12. Reactivity of ambient volatile organic compounds (VOCs) in summer of 2004 in Beijing

    Institute of Scientific and Technical Information of China (English)

    Shan Huang; Min Shao; Sihua Lu; Ying Liu

    2008-01-01

    Ambient volatile organic compounds (VOCs) were sampled at six sites in Beijing in the summer of 2004 and analyzed byGCMS. The chemical reactivities of 73 quantified VOCs species were evaluated by OH loss rates (L<,OH) and ozone formationpotentials (OFPs). Top 15 reactive species, mainly alkenes and aromatics, were identified by these two methods, and accounted formore than 70% of total reactivity of VOCs. In urban areas, isoprene was the most reactive species in term of OH loss rate,contributing 11.4% to the Loft of VOCs. While toluene, accounting for 9.4% of OFPs, appeared to have a long-time role in thephotochemical processes. Tongzhou site is obviously influenced by local chemical industry, but the other five sites showed typicalurban features influenced mainly by vehicular emissions.2008 Min Shao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  13. 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

  14. 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

  15. Dejima VOC dan rangaku

    Directory of Open Access Journals (Sweden)

    Bambang Wibawarta

    2008-10-01

    Full Text Available Japan and the Netherlands have maintained a special relationship for about 300years since the adoption of the National Seclusion policy, the so-called sakoku bythe Tokugawa shogunate (1603-1867. The Dutch began trading with Japan andengaging with Japanese society in 1600, when a Dutch ship, De Liefde, arrived inKyushu. The Tokugawa government measures regarding foreign policy includedregulations on foreign access to Japan and a prohibition on Japanese goingabroad. Between the middle of the seventeenth to the early nineteenth century,Japan was characterized by a stable political pattern in which representativesof the VOC (Dutch East India Company, were the only Europeans with a rightto trade in Japan. In the course of this period, the Japanese evaluation of theDutch changed from regarding them as commercial agents to seeing them asimporters of European knowledge. This paper is especially concerned with theinfluence of the so-called ‘Dutch Studies’ (rangaku on the early modernizationof Japan, especially with regard to medicine and the natural sciences. Thisresearch examines the development of rangaku and the trading between Japanand VOC at Dejima.

  16. Activated carbon fibers impregnated with Pd and Pt catalysts for toluene removal.

    Science.gov (United States)

    Liu, Zhen-Shu; Chen, Jian-Yuan; Peng, Yu-Hui

    2013-07-15

    Few studies have investigated the use of activated carbon fibers (ACFs) impregnated with noble metals for the catalytic oxidation of volatile organic compounds (VOCs). This study determined the removal efficiency of toluene as a function of time over ACF-supported metal catalysts. Two catalysts (Pt and Pd), five reaction temperatures (120, 150, 200, 250, and 300°C), and three oxygen contents (6%, 10%, and 21%) were investigated to determine the removal of toluene. To study the effects of the characteristics of the catalysts on toluene removal, the composition and morphology of the ACFs were analyzed using the BET, XPS, ICP, and FE-SEM. The results showed that the 0.42%Pd/ACFs showed greater activity for toluene removal than did 2.68%Pt/ACFs at a reaction temperature of 200°C and an oxygen content of 10%. The main removal mechanism of toluene over the 2.68%Pt/ACFs at reaction temperatures less than 200°C was adsorption. The long-term catalytic activity of the 2.68%Pt/ACFs for toluene removal at a reaction temperature of 250°C and an oxygen content of 10% could be obtained. Furthermore, toluene removal over the 2.68%Pt/ACFs at 200°C could be enhanced with increasing oxygen content.

  17. Active compost biofiltration of toluene.

    Science.gov (United States)

    Matteau, Y; Ramsay, B

    1997-01-01

    Composting of leaves and alfalfa (i.e. active compost) was used for the biofiltration of toluene-contaminated air in a 6-L biofilter (initial bed height: 180 mm). During the thermophilic phase (45 to 55 degrees C), toluene biodegradation rates reached 110 g toluene.m-3.h-1 at an inlet concentration of about 5 g.m-3 and a gas residence time of 90 seconds. The highest rates were obtained in the thermophilic phase suggesting a microbial adaptation was occurring. Biodegradation rates decreased rapidly (50% in 48 h) in the cooling stage. Under mesophilic conditions, the maximum biodegradation rates that could be obtained by increasing the inlet toluene concentration were near 89 g toluene.m-3.h-1 which is similar to that reported in the literature for mature compost biofilters. No volatile by-product was detected by gas chromatherapy. Mineralization of 14C-toluene and benzene showed that they were completely degraded into CO2 and H2O under both thermophilic and mesophilic conditions. Bacteria isolated from late mesophilic stage had the capacity to degrade all BTEX compounds but were not able to transform chlorinated compounds. No organisms were isolated which could use toluene as their sole source of carbon and energy at 50 degrees C. Active compost biofiltration should be an excellent process for the treatment of gaseous BTEX by biofiltration. This is the first report of thermophilic biofiltration of toluene.

  18. 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.

  19. Improvement in 8h-sampling rate assessment considering meteorological parameters variability for biogas VOC passive measurements in the surroundings of a French landfill.

    Science.gov (United States)

    Verriele, Marie; Allam, Nadine; Depelchin, Laurence; Le Coq, Laurence; Locoge, Nadine

    2015-11-01

    Passive sampling technology has been extensively used for long-term VOC atmospheric concentrations' monitoring. Its performances regarding the short-term measurements and related to VOC from biogas were evaluated in this work: laboratory scale experiments have been conducted in order to check the suitability of Radiello® diffusive samplers for the assessment of 8 h-VOC levels in highly changeable meteorological conditions; in a second step a short pilot field campaign was implemented in the vicinity of a West-French landfill. First of all, it was assessed that amongst a diversified list of 16 characteristic compounds from biogas, mercaptans, some halogenated, oxygenated compounds and terpenes could not be measured accurately by this passive technique either because they are not captured by the sorbent or they are not quantitatively desorbed in the chosen mediated analytical conditions. Moreover, it has been confirmed that sampling rates (SR) related to isopentane, THF, cyclohexane, toluene, p-xylene and n-decane are influenced by environmental factors: the main influence concerns the wind speed. From 2 m s(-1), when the velocity increases by 1 m s(-1), the SR increases from 12 to 32% depending on the COV (considering a linear dependence between 2 and 7 m s(-1)). Humidity has no effect on SR, and temperature influence is rather limited to less than 3% per degree. A comprehensive uncertainty estimation, including uncertainties linked to meteorological changes, has led to global relative uncertainties comprising between 18% and 54% from one VOC to another: a quite high value comparatively to those obtained without considering meteorological condition influences. To illustrate our results, targeted VOC were quantified in the field, on a single day: concentrations range between LD to 3 µg m(-3): relatively very low concentrations compared to those usually reported by literature.

  20. Acute Toluene Exposure Alters Expression of Genes in the Central Nervous System Associated With Synaptic Structure and Function

    Science.gov (United States)

    Toluene is a volatile organic compound (VOC) and a ubiquitous air pollutant of interest to EPA regulatory programs. Whereas its acute functional effects are well described, several modes of action in the CNS have been proposed. Therefore, we sought to identify potential pathways ...

  1. Assessment of ambient volatile organic compounds (VOCs) near major roads in urban Nanjing, China

    Science.gov (United States)

    Wang, P.; Zhao, W.

    2008-08-01

    Volatile organic compounds (VOCs) are a major component of atmospheric pollutants in Nanjing, a large city in the east of China. Accordingly, 12-h diurnal monitoring for ten consecutive days was performed adjacent to major roads in five districts, ca.1.5 m above ground level, in April, July and October 2006, and January 2007. The most numerous species of VOCs (benzene, toluene, ethylbenzene, m/ p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, tetrachloromethane, trichloroethane and tetrachloroethane) were selected as the target pollutants for this field study of atmospheric distribution. The eleven VOCs were mostly found in gas phase due to their high vapor pressures. Gas-phase concentrations ranged between 0.6 and 67.9 μg m - 3 . Simultaneously, the levels of those VOCs measured near major roads were associated slightly with their regional background level. For all these areas, as expected, the high traffic area was the highest in terms of concentration. A positive correlation was also found between the VOC levels and traffic density. Our studies also provided VOC distribution, and vertical/horizontal profiles. The results show that traffic-related exposure to VOCs in major road microenvironments is higher than elsewhere and poses a potential threat to pedestrians, commuters, and traffic-exposed workers.

  2. 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 (NOx 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 NOx-limited as indicated by measured VOCs/NOx 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 NOx-limited regime, although this sensitivity depends strongly on how much NOx is present.

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

    Science.gov (United States)

    Kaltsonoudis, Christos; Kostenidou, Evangelia; Florou, Kalliopi; Psichoudaki, Magda; Pandis, Spyros N.

    2016-11-01

    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.

  4. On speciation of VOC localization

    Science.gov (United States)

    Chen, S.; Chang, J.; Wang, J.

    2011-12-01

    Most of the gas-phase chemical mechanisms successfully used in gas-phase atmospheric chemical processes, such as CBM-Z, RADM2 or SAPRC-07, treat hundreds of VOC as lumped organic species by their chemical characteristics. Most of the model results are compared with total VOC observations, and it is not appropriate to compare lumped VOC simulations to observations even if there are separate VOC observations like Photochemical Assessment Monitoring Stations (PAMS). While the PAMS Air Quality Model (PAMS-AQM) is developed, separate organic species observed by PAMS without a doubt can be directly compared with model simulations. From the past case study (Chen et al., 2010), it shows a major and very significant finding in that detailed emissions of VOC in the existing emissions database are often in error in Taiwan or other countries due to the fact that the annual VOC emissions are classified into hundreds of species-specific emissions by using the speciation factors following the protocol of the U.S. EPA (AP-42). Based on all PAMS observations from 2006-2007, four base cases with well comparable meteorological simulations were selected for the unified correction for all sources in Taiwan. After the PAMS species emissions are modified, the diurnal patterns and simulation-observation correlation for most of the PAMS species are improved, and the concentration levels are more comparable with those of observations. More expanded case studies also revealed necessary corrections for the PAMS species emissions. Sensitivity analyses for lumped organic species with modified PAMS species emissions are also conducted. After modified PAMS emissions are added into lumped VOC emissions, there is an increase of only 10% of totally VOC emissions. While the sources of the lumped VOC emissions are changed, ozone formation shows no significant change with modified lumped VOC emissions. This helps to support the argument that for ozone simulation, the lumped VOC processes balance out

  5. 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

  6. 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

  7. Biological anoxic treatment of O{sub 2}-free VOC emissions from the petrochemical industry: A proof of concept study

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Raúl; Souza, Theo S.O. [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr Mergelina s/n, 47011 Valladolid (Spain); Glittmann, Lina [Ostfalia University of Applied Sciences, Department of Supply Engineering, Wolfenbüttel (Germany); Pérez, Rebeca [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr Mergelina s/n, 47011 Valladolid (Spain); Quijano, Guillermo, E-mail: gquijano@iq.uva.es [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr Mergelina s/n, 47011 Valladolid (Spain)

    2013-09-15

    Highlights: • The treatment of O{sub 2}-free VOC emissions can be done by means of denitrifying processes. •Toluene vapors were successfully removed under anoxic denitrifying conditions. • A high bacterial diversity was observed. • Actinobacteria and Proteobacteria were the predominant phyla. • The nature and number of metabolites accumulated varied with the toluene load -- Abstract: An innovative biofiltration technology based on anoxic biodegradation was proposed in this work for the treatment of inert VOC-laden emissions from the petrochemical industry. Anoxic biofiltration does not require conventional O{sub 2} supply to mineralize VOCs, which increases process safety and allows for the reuse of the residual gas for inertization purposes in plant. The potential of this technology was evaluated in a biotrickling filter using toluene as a model VOC at loads of 3, 5, 12 and 34 g m{sup −3} h{sup −1} (corresponding to empty bed residence times of 16, 8, 4 and 1.3 min) with a maximum elimination capacity of ∼3 g m{sup −3} h{sup −1}. However, significant differences in the nature and number of metabolites accumulated at each toluene load tested were observed, o- and p-cresol being detected only at 34 g m{sup −3} h{sup −1}, while benzyl alcohol, benzaldehyde and phenol were detected at lower loads. A complete toluene removal was maintained after increasing the inlet toluene concentration from 0.5 to 1 g m{sup −3} (which entailed a loading rate increase from 3 to 6 g m{sup −3} h{sup −1}), indicating that the system was limited by mass transfer rather than by biological activity. A high bacterial diversity was observed, the predominant phyla being Actinobacteria and Proteobacteria.

  8. Benzene and toluene in the surface air of northern Eurasia from TROICA-12 campaign along the Trans-Siberian Railway

    Science.gov (United States)

    Skorokhod, Andrey I.; Berezina, Elena V.; Moiseenko, Konstantin B.; Elansky, Nikolay F.; Belikov, Igor B.

    2017-05-01

    Volatile organic compounds (VOCs) were measured by proton transfer reaction mass spectrometry (PTR-MS) on a mobile laboratory in a transcontinental TROICA-12 (21 July-4 August 2008) campaign along the Trans-Siberian Railway from Moscow to Vladivostok. Surface concentrations of benzene (C6H6) and toluene (C7H8) along with non-methane hydrocarbons (NMHCs), CO, O3, SO2, NO, NO2 and meteorology are analyzed in this study to identify the main sources of benzene and toluene along the Trans-Siberian Railway. The most measurements in the TROICA-12 campaign were conducted under low-wind/stagnant conditions in moderately ( ˜ 78 % of measurements) to weakly polluted ( ˜ 20 % of measurements) air directly affected by regional anthropogenic sources adjacent to the railway. Only 2 % of measurements were identified as characteristic of highly polluted urban atmosphere. Maximum values of benzene and toluene during the campaign reached 36.5 and 45.6 ppb, respectively, which is significantly less than their short-term exposure limits (94 and 159 ppb for benzene and toluene, respectively). About 90 % of benzene and 65 % of toluene content is attributed to motor vehicle transport and 10 and 20 %, respectively, provided by the other local- and regional-scale sources. The highest average concentrations of benzene and toluene are measured in the industrial regions of the European Russia (up to 0.3 and 0.4 ppb for benzene and toluene, respectively) and south Siberia (up to 0.2 and 0.4 ppb for benzene and toluene, respectively). Total contribution of benzene and toluene to photochemical ozone production along the Trans-Siberian Railway is about 16 % compared to the most abundant organic VOC - isoprene. This contribution, however, is found to be substantially higher (up to 60-70 %) in urbanized areas along the railway, suggesting an important role of anthropogenic pollutant sources in regional ozone photochemistry and air quality.

  9. Vapour-liquid equilibrium relationship between toluene and mixed surfactants.

    Science.gov (United States)

    Tian, Senlin; Li, Yingjie; Mo, Hong; Ning, Ping

    2012-01-01

    Micellar partitioning of volatile organic compounds (VOCs) in surfactant solutions and its effects on vapour-liquid equilibrium is fundamental to the overall design and implementation ofsurfactant-enhanced remediation. Knowledge of the vapour-liquid equilibrium partitioning coefficients for VOCs, especially in contaminated soils and groundwater in which they exist, is required. Headspace experiments were performed to quantify the effect of three mixed surfactants, cetyltrimethyl ammonium bromide (CTMAB) with tetrabutylammonium bromide (TBAB), sodium dodecyl sulphate (SDS) with Triton X-405 (TX405), and CTMAB with Triton X-100 (TX100), on the apparent Henry's constants (Hc) of toluene at temperatures ranging from 25 degrees C to 40 degrees C. The Hc values were significantly reduced in the presence of all three mixed surfactants at concentrations above their critical micelle concentrations (CMC). Mixed micellar partitioning, showing effects on the vapour-liquid equilibrium of toluene, was primarily responsible for the significant reduction of Hc in their mixed systems. The mixed surfactants CTMAB-TX100 had the greatest effect on Hc above the CMC, followed by SDS-TX405, then CTMAB-TBAB. Mixed systems of CTMAB-TX100 decreased Hc at concentrations significantly lower than the SDS-TX405 and CTMAB-TBAB concentrations, because of to the lower CMC of CTMAB-TX100. Vapour-liquid equilibrium data were also tested against the model (Hc = H/(1 + K(X - CMC)) that described the partitioning of VOCs in vapour-water-micelle phases. The correlation of Hc with mixed surfactant concentrations (X) and CMC can be utilized as an effective tool to predict the Hc by mixed surfactants.

  10. Removal of VOCs from air stream with corrugated sheet as adsorbent

    Directory of Open Access Journals (Sweden)

    Rabia Arshad

    2016-10-01

    Full Text Available A large proportional of volatile organic compounds (VOCs are released into the environment from various industrial processes. The current study elucidates an application of a simple adsorption phenomenon for removal of three main types of VOCs, i.e., benzene, xylene and toluene, from an air stream. Two kinds of adsorbents namely acid digested adsorbent and activated carbon are prepared to assess the removal efficiency of each adsorbent in the indoor workplace environment. The results illustrate that the adsorbents prepared from corrugated sheets were remarkably effective for the removal of each pollutant type. Nevertheless, activated carbon showed high potential of adsorbing the targeted VOC compared to the acid digested adsorbent. The uptake by the adsorbents was in the following order: benzene > xylene > toluene. Moreover, maximum adsorption of benzene, toluene and xylene occurred at 20 °C and 1.5 cm/s for both adsorbents whereas minimum success was attained at 30 °C and 1.0 cm/s. However, adsorption pattern are found to be similar for each of the the three aromatic hydrocarbons. It is concluded that the corrugated sheets waste can be a considered as a successful and cost-effective solution towards effective removal of targeted pollutants in the air stream.

  11. Start-up and the effect of gaseous ammonia additions on a biofilter for the elimination of toluene vapors

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Revah, S. [UAM-Iztapalapa, Distrito Federal (Mexico). Dept. de Ingenieria de Procesos e Hidraulica; Auria, R. [ORSTOM, Los Morales (Mexico)

    1998-11-20

    Biotechnological techniques, including biofilters and biotrickling filters are increasingly used to treat air polluted with VOCs (Volatile Organic Compounds). In this work, the start-up, the effect of the gaseous ammonia addition on the toluene removal rate, and the problems of the heat accumulation on the performance of a laboratory scale biofilter were studied. The packing material was sterilized peat enriched with a mineral medium and inoculated with an adapted consortium (two yeast and five bacteria). Start-up showed a short adaptation period and an increased toluene elimination capacity (EC) up to a maximum of 190 g/m{sup 3}/h. This was related to increased CO{sub 2} outlet concentration and temperature gradients between the packed bed and the inlet (Tm-Tin). These events were associated with the growth of the microbial population. The biofilter EC decreased thereafter, to attain a steady state of 8 g/m{sup 3}/h. At this point, gaseous ammonia was added. EC increased up to 80 g/m{sup 3}/h, with simultaneous increases on the CO{sub 2} concentration and (Tm-Tin).

  12. Treatment of gaseous toluene in three biofilters inoculated with fungi/bacteria: Microbial analysis, performance and starvation response.

    Science.gov (United States)

    Cheng, Zhuowei; Lu, Lichao; Kennes, Christian; Yu, Jianming; Chen, Jianmeng

    2016-02-13

    Bacteria and fungi are often utilized for the biodegradation of organic pollutants. This study compared fungal and/or bacterial biofiltration in treating toluene under both steady and unsteady states. Fungal biofilter (F-BF) removed less toluene than both bacterial biofilters (B-BF) and fungal & bacterial biofilters (F&B-BF) (60% vs >90%). The mineralization ratio was also lower in F-BF-levels were 2/3 and 1/2 of those values obtained by the other biofilters. Microbial analysis showed that richer communities were present in B-BF and F&B-BF, and that the Hypocreales genus which Trichoderma viride belongs to was much better represented in F&B-BF. The F&B-BF also supported enhanced robustness after 15-day starvation episodes; 1 day later the performance recovered to 80% of the original removal level. The combination of bacteria and fungi makes biofiltration a good option for VOC treatment including better removal and performance stability versus individual biofilters (bacteria or fungi dominated).

  13. Non-invasive toluene sensor for early diagnosis of lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Rahul; Srivastava, Sudha, E-mail: sudha.srivastava@jiit.ac.in [Department of Biotechnology, Jaypee Institute of Information Technology, A-10, Sector-62, Noida-201307,Uttar Pradesh (India)

    2016-04-13

    Here we present, quantification of volatile organic compounds in human breath for early detection of lung cancer to increase survival probability. Graphene oxide nanosheets synthesized by modified Hummer’s method were employed as a sensing element to detect the presence of toluene in the sample. Optical and morphological characterization of synthesized nanomaterial was performed by UV-Visible spectroscopy and scanning electron microscopy (SEM) respectively. Spectroscopic assay shows a linearly decreasing intensity of GO absorption peak with increasing toluene concentration with a linear range from 0-200 pM. While impedimetric sensor developed on a graphene oxide nanosheetsmodified screen printed electrodes displayed a decreasing electron transfer resistance increasing toluene with much larger linear range of 0-1000 pM. Reported techniques are advantageous as these are simple, sensitive and cost effective, which can easily be extended for primary screening of other VOCs.

  14. Non-invasive toluene sensor for early diagnosis of lung cancer

    Science.gov (United States)

    Saxena, Rahul; Srivastava, Sudha

    2016-04-01

    Here we present, quantification of volatile organic compounds in human breath for early detection of lung cancer to increase survival probability. Graphene oxide nanosheets synthesized by modified Hummer's method were employed as a sensing element to detect the presence of toluene in the sample. Optical and morphological characterization of synthesized nanomaterial was performed by UV-Visible spectroscopy and scanning electron microscopy (SEM) respectively. Spectroscopic assay shows a linearly decreasing intensity of GO absorption peak with increasing toluene concentration with a linear range from 0-200 pM. While impedimetric sensor developed on a graphene oxide nanosheetsmodified screen printed electrodes displayed a decreasing electron transfer resistance increasing toluene with much larger linear range of 0-1000 pM. Reported techniques are advantageous as these are simple, sensitive and cost effective, which can easily be extended for primary screening of other VOCs.

  15. H2S and VOCs abatement robustness in biofilters and air diffusion bioreactors: A comparative study.

    Science.gov (United States)

    Lebrero, Raquel; Rodríguez, Elisa; Martin, María; García-Encina, Pedro A; Muñoz, Raúl

    2010-07-01

    The robustness of a conventional biofilter and an air diffusion bioreactor (ADB) was comparatively evaluated in laboratory-scale plants treating a mixture of H2S, butanone, toluene and alpha-pinene at gas residence times of 50 s. Under steady state conditions, H2S, butanone and toluene were almost completely degraded, while alpha-pinene removal did not exhibit removal efficiencies (REs) higher than 11.0 +/- 2.3%. Fluctuations in temperature from 8 degrees C to 30 degrees C did not impact significantly process performance in any of the biotechnologies tested. However, while the ADB unit was able to cope with three and six fold step increases in pollutant loadings, volatile organic compounds (VOCs) REs noticeably decreased in the biofilter when subjected to a six fold step change (i.e. 90% reduction for butanone and 30% for toluene). A process shutdown of five days resulted in the temporary loss of butanone and toluene RE in the ADB system. A lack of irrigation during five days caused a slight decrease in the biofilter REs, while a failure in the pH control system drastically affected the ADB performance. Finally, process robustness was quantified. The calculated overall risks showed that both biotechnologies were reliable for H2S and VOCs treatment in wastewater treatment plants, ADB diffusion exhibiting a higher robustness towards fluctuations commonly found under routine operation. This robustness was further confirmed by the high stability of the DGGE profiles.

  16. Personal volatile organic compound (VOC) exposure of children attending elementary schools adjacent to industrial complex

    Science.gov (United States)

    Park, Kun-Ho; Jo, Wan-Kuen

    The major deficiency in linking the effects of environmental exposure to children's health is the lack of data on the exposure of children to hazardous environmental pollutants. Accordingly, the present study compared the personal volatile organic compound (VOC) exposure of children from four elementary schools at different proximities to the Daegu Dyeing Industrial Complex (DDIC) and adjacent to different traffic densities. The personal air concentrations of four VOCs (toluene, m, p-xylenes, and o-xylene) were significantly higher for the children attending the school (S1) closest to the boundary of the DDIC compared to the children attending the school (S2) further away. The DDIC was the likely primary cause for the elevated personal air concentrations of the four VOCs in the children attending the school nearest the DDIC. The personal exposure to toluene and methyl tertiary-butyl ether (MTBE) for the children attending the school near a major roadway with a high traffic density was significantly higher than that for the children attending the school near a roadway with a low traffic density. The difference in the breath concentrations was generally similar to the difference in the personal air concentrations among the children from the four schools. In contrast to the children attending schools in low-income areas, the children attending schools in high-income areas exhibited no significant difference in the concentrations of any of the target VOCs in the personal air and breath samples between the children living with and without a smoker in the home.

  17. Evaluation of Hydrogen/Oxygen Release Compounds for the Remediation of VOCs

    Directory of Open Access Journals (Sweden)

    S. Fiore

    2011-01-01

    Full Text Available Problem statement: Volatile Organic Compounds (VOCs are widespread in groundwater of industrialized areas and in situ remediation intervents characterized by a high environmental compatibility are of main interest. The scope of this study is the evaluation of the potential of two innovative reagents (HRC and ORC from Regenesis for the remediation of Volatile Organic Compounds (VOCs. The reagents respectively perform reduction and oxidation mechanisms, both effective in the degradation of VOCs. Approach: Hydrogen Release Compound (HRC and Oxygen Release Compound (ORC were tested about the degradation of Benzene, Toluene, Ethylbenzene and Xylene (BTEX and some chlorinated aliphatic compounds (CAHs. Five series of batch tests were performed with an artificial polluted aqueous phase and some soil coming from a polluted site in which natural attenuation of VOCs occurs. Results: ORC exhibited a good efficiency in the degradation of BTEX and the zero order model was found as a reliable approximation of experimental data (with the exceptions of benzene and toluene, for which a first order kinetic model was trustworthy, while HRC showed a good efficiency in the degradation of CAHs and a first order model consistently estimated almost all experimental data. The experimental data were modeled by means of different mathematical equations, considering zero and first order kinetics and the results were discussed and compared. Conclusions: On the grounds of the performed tests, Oxygen Release Compound (ORC is effective in BTEX degradation and Hydrogen Release Compound (HRC in CAHs removal.

  18. Electronic nose system combined with membrane interface probe for detection of VOCs in water

    Science.gov (United States)

    Cho, Junghwan; Howard, Zachary; Kurup, Pradeep

    2011-09-01

    This paper describes a novel electronic nose system combined with a membrane interface probe (MIP) for detecting volatile organic compounds (VOCs) in water. The MIP is an in situ tool that allows the detection of certain VOCs in the soil via a pushed or driven probe. The MIP was combined with a sensor array consisting of four different tin-oxide gas sensors known as an electronic nose (e-nose). The designed e-nose system was calibrated in aqueous media spiked with benzene, toluene, ethylbenzene, and p-xylene (BTEX) at concentrations of 100, 250, and 500 ppm. Since the experiment was conducted utilizing five repetitions for each analyte, a data set of 60 measurements was prepared for principal components analysis (PCA). The results of the PCA showed that two principal components contain more than 99% variance information and each VOC is separable and detectable by the e-nose.

  19. Modeling unsteady-state VOC transport in simulated waste drums. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    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&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.

  20. 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

  1. 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.

  2. VOC emissions during outdoor ship painting and health-risk assessment

    Science.gov (United States)

    Malherbe, Laure; Mandin, Corinne

    Painting of ship external surfaces in building or repair shipyards generates significant emissions of volatile organic compounds (VOC) to the atmosphere. Such emissions have not been specifically regulated so far. The purpose of our study is therefore to evaluate the quantities and as far as possible the nature of the emitted VOC, to characterize the dispersion of these chemicals in the atmosphere and to assess the exposure and resulting health risks for surrounding populations. This study is focused on VOC emitted during outdoor work involving use of paints and solvents. VOC emissions are diffuse, since they come from the whole painted surfaces. A methodology for quantifying them is developed and tested, using information provided by ALSTOM—Chantiers de l'Atlantique and data found in paint technical sheets. Its reliability is checked against emission values established by ALSTOM or found in literature. Then, for two particular situations, construction on one hand, repair on the other hand, atmospheric dispersion of total VOC is simulated to assess the long-term impact (characterized by the plume extension and the annual mean concentrations) of these compounds. Finally, a health-risk assessment based on the estimates is carried out to evaluate the risks by inhalation for people living near the site. Considering the presumed composition of paints and the available reference toxicological values, total VOC are entirely assimilated to toluene. In both examples (construction and repair) and in the current state of knowledge, the calculated risk is not of health concern. Several ways for taking this study further are proposed: a more exhaustive collection of data relative to VOC and other substances contained in paints, on-site measurement of VOC in the ambient air, characterization of diffuse emissions related to other activities, such as purging or welding, and other pollutants, like particles.

  3. 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.

  4. Draft Genome Sequence of Uncultivated Toluene-Degrading Desulfobulbaceae Bacterium Tol-SR, Obtained by Stable Isotope Probing Using [13C6]Toluene.

    Science.gov (United States)

    Abu Laban, Nidal; Tan, BoonFei; Dao, Anh; Foght, Julia

    2015-01-15

    The draft genome of a member of the bacterial family Desulfobulbaceae (phylum Deltaproteobacteria) was assembled from the metagenome of a sulfidogenic [(13)C6]toluene-degrading enrichment culture. The "Desulfobulbaceae bacterium Tol-SR" genome is distinguished from related, previously sequenced genomes by suites of genes associated with anaerobic toluene metabolism, including bss, bbs, and bam.

  5. Thermal response and recyclability of poly(stearylacrylate-co-ethylene glycol dimethacrylate) gel as a VOCs absorbent

    Science.gov (United States)

    The development of absorbent materials for volatile organic compounds (VOCs) is in demand for a variety of environmental applications including protective barriers for VOCs point sources. One of the challenges for the currently available VOCs absorbents is their recyclability. In this study, we syn...

  6. Vertical profiles of ozone, VOCs and meteorological parameters in within and outside of Mexico City during the MILAGRO field Campaign

    Science.gov (United States)

    Marquez, C.; Greenberg, J.; Bueno, E.; Bernabe, R.; Aguilar, J.; Blanco, S.; Wöhrnschimmel, H.; Guenther, A.; Cardenas, B.; Turnipseed, A.

    2007-05-01

    High ozone levels with maxima over 250 ppb have been an air quality problem in Mexico City for more than a decade. This ozone is produced in the daytime by photochemical reactions, initiated by its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of solar ultraviolet radiation. The objective of this work is to contribute to the understanding of the evolution of these air pollutants at different heights of the boundary layer by means of vertical profile measurements. Ozone, VOCs and meteorological vertical profiles were determined in Northern Mexico City (T0 site) using a tethered balloon for 10 days during the MILAGRO field Campaign 2006, between 4 AM and 4 PM. Measurements were done up to 1000 meter above ground (ozone and meteorological parameters) and up to 200 m above ground for VOCs. VOCs samples were collected during 4 minutes in canisters and analyzed with GC-FID to identify 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane and o-xylene). For 4 of the days, VOC integrated samples were also taken using personal pumps and absorbent cartridges at height between 200 and 1000 m. Sample cartridges were analyzed by GC-MS for volatile organic compounds (n-butane, i-pentane, n- pentane, benzene, toluene, ethyl-benzene, o-xylene, m&p-xylene, 1,2,4-tri-methyl-benzene and C3-benzenes). Ozone vertical profiles, frequently presented high concentrations above 400 m in the early morning. During the daytime, more homogeneous profiles indicate an increased vertical mixing. VOCs profiles show similar concentrations for all heights at dawn. In the morning, highest concentrations were determined at a height of about 100 meter, whereas at noon and in the afternoon concentrations decreased with height. Comparing VOC concentrations during the course of a day, highest values are measured in the morning. The highest VOC concentrations were propane, butane, and toluene. For some

  7. 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

  8. [Study on control and management for industrial volatile organic compounds (VOCs) in China].

    Science.gov (United States)

    Wang, Hai-Lin; Zhang, Guo-Ning; Nei, Lei; Wang, Yu-Fei; Hao, Zheng-Ping

    2011-12-01

    Volatile organic compounds (VOCs) emitted from industrial sources account for a large percent of total anthropogenic VOCs. In this paper, VOCs emission characterization, control technologies and management were discussed. VOCs from industrial emissions were characterized by high intensity, wide range and uneven distribution, which focused on Bejing-Tianjin Joint Belt, Shangdong Peninsula, Yangtze River Delta and the Pearl River Delta. The current technologies for VOCs treatment include adsorption, catalytic combustion, bio-degradation and others, which were applied in petrochemical, oil vapor recovery, shipbuilding, printing, pharmaceutical, feather manufacturing and so on. The scarcity of related regulations/standards plus ineffective supervision make the VOCs management difficult. Therefore, it is suggested that VOCs treatment be firstly performed from key areas and industries, and then carried out step by step. By establishing of actual reducing amount control system and more detailed VOCs emission standards and regulations, applying practical technologies together with demonstration projects, and setting up VOCs emission registration and classification-related-charge system, VOCs could be reduced effectively.

  9. Leaching of toluene-neoprene adhesive wastes.

    Science.gov (United States)

    Font, R; Sabater, M C; Martínez, M A

    2001-03-01

    This work consists of the study of the extraction of solvent (toluene) from a polymeric (neoprene) substrate during a leaching process. Total organic carbon (TOC) is the main contaminant parameter in the leaching of these systems due to the solution of the toluene and the dispersion of the polymer. The toxicity of the extracts was measured with a Microtox equipment, using Photobacteria phosphoreum, deducing that the toxicity of the extracts is low due to the low solubility of toluene but that the toxicity of toluene is high. On the basis of the experimental results, the amount of toluene diffused vs time in plane sheet systems was studied. A kinetic model has been developed considering two stages: In the first stage, the toluene diffuses into the system across the neoprene chains at a constant rate, not depending on the initial toluene concentration. This fact is explained by considering that there is a constant difference of the toluene concentration between the interface with the water and the inner part of the sample. In the second stage, the dispersion of the polymer with the corresponding amount of toluene takes place. The diffusion of toluene in the leaching process is compared and analyzed considering the diffusion of toluene in a desorption process in air so that the difference of toluene concentration between the interface and the interior can be estimated. A mathematical model is also proposed for considering the leaching process in other operating conditions.

  10. 27 CFR 21.132 - Toluene.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Toluene. 21.132 Section 21... TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a..., Standard No. D 362-75 for industrial grade toluene; for incorporation by reference, see § 21.6(b).) When...

  11. Diversity of Five Anaerobic Toluene-Degrading Microbial Communities Investigated Using Stable Isotope Probing

    Science.gov (United States)

    Sun, Weimin

    2012-01-01

    Time-series DNA-stable isotope probing (SIP) was used to identify the microbes assimilating carbon from [13C]toluene under nitrate- or sulfate-amended conditions in a range of inoculum sources, including uncontaminated and contaminated soil and wastewater treatment samples. In all, five different phylotypes were found to be responsible for toluene degradation, and these included previously identified toluene degraders as well as novel toluene-degrading microorganisms. In microcosms constructed from granular sludge and amended with nitrate, the putative toluene degraders were classified in the genus Thauera, whereas in nitrate-amended microcosms constructed from a different source (agricultural soil), microorganisms in the family Comamonadaceae (genus unclassified) were the key putative degraders. In one set of sulfate-amended microcosms (agricultural soil), the putative toluene degraders were identified as belonging to the class Clostridia (genus Desulfosporosinus), while in other sulfate-amended microcosms, the putative degraders were in the class Deltaproteobacteria, within the family Syntrophobacteraceae (digester sludge) or Desulfobulbaceae (contaminated soil) (genus unclassified for both). Partial benzylsuccinate synthase gene (bssA, the functional gene for anaerobic toluene degradation) sequences were obtained for some samples, and quantitative PCR targeting this gene, along with SIP, was further used to confirm anaerobic toluene degradation by the identified species. The study illustrates the diversity of toluene degraders across different environments and highlights the utility of ribosomal and functional gene-based SIP for linking function with identity in microbial communities. PMID:22156434

  12. VOC emission rates and emission factors for a sheetfed offset printing shop.

    Science.gov (United States)

    Wadden, R A; Scheff, P A; Franke, J E; Conroy, L M; Javor, M; Keil, C B; Milz, S A

    1995-04-01

    Emission rates were determined during production for a sheetfed offset printing shop by combining the measured concentrations and ventilation rates with mass balance models that characterized the printing space. Air samples were collected simultaneously on charcoal tubes for 12 separate 1-hour periods at 6 locations. Air samples and cleaning solvents were analyzed by gas chromatography for total volatile organic compounds (VOC) and 13 hydrocarbons. The average VOC emission rate was 470 g/hr with a range of 160-1100 g/hr. These values were in good agreement with the amounts of VOC, hexane, toluene, and aromatic C9s determined from estimated solvent usage and measured solvent compositions. Comparison of the emission rates with source activities indicated an emission factor of 30-51 g VOC/press cleaning. Based on the test observations it was estimated that this typical small printing facility was likely to release 1-2 T VOC/year. The methodology also may be useful for the surface coating industry, as emission rates in this study were determined without recourse to a temporary total enclosure and without interfering with worker activities, increasing worker exposure, or increasing safety and explosion hazards.

  13. Biodegradation of gaseous toluene with mixed microbial consortium in a biofilter: steady state and transient operation.

    Science.gov (United States)

    Rajamanickam, Ravi; Baskaran, Divya

    2017-09-04

    Petroleum oil refineries are massive emitters of risky volatile organic compounds (VOCs). Among the VOCs, toluene is taken into account as a significant pollutant. In the present study, a compost biofilter is used to treat the toluene vapor. However, an elimination capacity and removal efficiency of the biofilter was investigated for a wide range of toluene concentrations (0.29-3.8 g m(-3)) and operated for 54 days effectively. Elimination capacity of 93 g m(-3) h(-1) was recorded as maximum value at a toluene inlet concentration of 114 g m(-3) h(-1). An elimination capacity was perpetually better at the lower section of the biofilter, and therefore, the value was around 40-60 g m(-3) h(-1). The high removal efficiency of 97% was obtained at inlet toluene load of 60.55 g m(-3) h(-1). Hence, the biofilm was quite sensitive to handling transient loading conditions. The pressure drop had no vital impact on the biofilter performance. An Ottengraf model was applied to all phase of biofilter operation in each of the diffusion limiting region and reaction limiting region. The parameters of the model K 1 (75.95 g(1/2) m(-3/2) h(-1)) and K 0 (90.51 g m(-3) h(-1)) were obtained from diffusion and reaction limiting region severally. However, K 1 was used to calculate the theoretical elimination capacities, and therefore, K 0 was used to discover the biofilm thickness. By the way, the average biofilm thickness was found to be 0.98 mm from reaction limiting region.

  14. Application of high silica zeolite ZSM-5 in a hybrid treatment process based on sequential adsorption and ozonation for VOCs elimination.

    Science.gov (United States)

    Zaitan, Hicham; Manero, Marie Hélène; Valdés, Héctor

    2016-03-01

    In this study, a hydrophobic synthetic zeolite, namely ZSM-5 is chosen as an adsorbent/catalyst for toluene removal. Experimental results showed that toluene adsorption onto ZSM-5 was favourable, following a Langmuir adsorption isotherm model. ZSM-5 zeolite was regenerated using gaseous ozone at low temperature. Adsorbed toluene was oxidised, releasing mainly CO2 and H2O. Traces of oxidation by-products such as acetic acid and acetaldehyde were formed and remained adsorbed after the oxidativate regeneration with ozone. After four successive cycles of adsorption/ozonation, the adsorption efficiency was not affected (92%-99%). These results showed that volatile organic compound (VOC) removal by adsorption onto ZSM-5 zeolite followed by ozone regeneration could be used as a promising hybrid process for the control of VOC emissions in terms of efficiency.

  15. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  16. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Ming-Huan [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Institute of Neuroscience, National Changchi University, Taipei, Taiwan (China); Chung, Shiang-Sheng [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Department of Pharmacy, Yuli Veterans Hospital, Hualien, Taiwan (China); Stoker, Astrid K.; Markou, Athina [Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA (United States); Chen, Hwei-Hsien, E-mail: hwei@nhri.org.tw [Department of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan (China); Division of Mental Health and Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan (China)

    2012-12-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-D-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and by inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. -- Highlights: ► Toluene induces impairments in Rotarod test and novel object recognition test. ► Toluene lowers rectal temperature and ICSS thresholds in mice. ► Sarcosine reverses toluene-induced changes in motor, memory and body temperature. ► Sarcosine pretreatment does not affect toluene

  17. Microbial community and function of enrichment cultures with methane and toluene.

    Science.gov (United States)

    Su, Yao; Xia, Fang-Fang; Tian, Bao-Hu; Li, Wei; He, Ruo

    2014-04-01

    The interaction effect of co-existence of toluene and CH4 on community and activity of methanotrophs and toluene-degrading bacteria was characterized in three consortia enriched with CH4 and toluene (MT), toluene (T), and CH4 (M), respectively, in this study. The CH4 oxidation activity in the enrichment culture of MT was significantly lower than that of M at the end of the experiment (P = 0.001). The toluene degradation rate could be enhanced by continuous addition of CH4 and toluene in the initial days, but it was inhibited in the later days. Phylogenetic analysis of 16S rRNA genes showed that Proteobacteria and Bacteroidetes were dominant in the three enriched consortia, but the community of methanotrophs and toluene-degrading bacteria was significantly affected by the co-existence of CH4 and toluene. Both Methylosinus (91.8 %) and Methylocystis (8.2 %) were detected in the enrichment culture of MT, while only Methylocystis species were detected in M. The toluene-degrading bacteria including Burkholderia, Flavobacteria, Microbacterium, and Azoarcus were all detected in the enrichment culture of T. However, only Azoarcus was found in the enrichment culture of MT. Significantly higher contents of extracellular polymeric substances polysaccharose and protein in the enrichment culture of MT than that of T and M suggested that a higher environmental stress occurred in the enrichment culture of MT.

  18. [Pollution characteristics and health risk assessment of atmospheric VOCs in the downtown area of Guangzhou, China].

    Science.gov (United States)

    Li, Lei; Li, Hong; Wang, Xue-Zhong; Zhang, Xin-Min; Wen, Chong

    2013-12-01

    The measurements of 31 kinds of VOCs in the ambient air of a site were carried out in the downtown of Guangzhou by online method from November 5, 2009 to November 9, 2009. The ambient level and composition characteristics, temporal variation characteristics, sources identification, and chemical reactivity of VOCs were studied, and the health risk of VOCs in the ambient air in the study area was assessed by using the international recognized health risk assessment method. Results showed that the mean and the range of the mass concentrations of 31 VOCs were 114.51 microg x m(-3) and 29.42-546.06 microg x m(-3), respectively. The mass concentrations of 31 VOCs, and those of alkanes, alkenes, and aromatics all showed a changing trend of higher in the morning and in the evening, and lower at noontime. Vehicular exhaust, gasoline and liquefied petroleum gas evaporates were the main sources of VOCs with the volatilization of paints and solvents being important emission sources. Toluene, trans-2-butene, m/p-xylene, i-butane, and 1,3,5-trimethylbenzene were the key reactive species among the 31 VOCs. Vehicular exhaust and gasoline evaporation were the main sources of VOCs leading to the formation of ozone. Health risk assessment showed that n-hexane, 1,3-butadiene, benzene, toluene, ethylbenzene, m/p-xylene and o-xylene had no appreciable risk of adverse non-cancer health effect on the exposed population, but 1, 3-butadiene and benzene had potential cancer risk. By comparing the corresponding data about health risk assessment of benzene compounds in some cities in China, it is concluded that benzene can impose relatively high cancer risk to the exposed populations in the ambient air of some cities in China. Therefore, strict countermeasures should be taken to further control the pollution of benzene in the ambient air of cities, and it is imperative to start the related studies and develop the atmospheric environmental health criteria and national ambient air quality

  19. Primary VOC emissions from Commercial Aircraft Jet Engines

    Science.gov (United States)

    Kilic, Dogushan; Huang, Rujin; Slowik, Jay; Brem, Benjamin; Durdina, Lukas; Rindlisbacher, Theo; Baltensperger, Urs; Prevot, Andre

    2014-05-01

    Air traffic is growing continuously [1]. The increasing number of airplanes leads to an increase of aviation emissions giving rise to environmental concerns globally by high altitude emissions and, locally on air quality at the ground level [2]. The overall impact of aviation emissions on the environment is likely to increase when the growing air transportation trend [2] is considered. The Aviation Particle Regulatory Instrumentation Demonstration Experiment (APRIDE)-5 campaign took place at Zurich Airport in 2013. In this campaign, aircraft exhaust is sampled during engine acceptance tests after engine overhaul at the facilities of SR Technics. Direct sampling from the engine core is made possible due to the unique fixed installation of a retractable sampling probe and the use of a standardized sampling system designed for the new particulate matter regulation in development for aircraft engines. Many of the gas-phase aircraft emissions, e.g. CO2, NOX, CO, SO2, hydrocarbons, and volatile organic compounds (VOC) were detected by the instruments in use. This study, part of the APRIDE-5 campaign, focuses on the primary VOC emissions in order to produce emission factors of VOC species for varying engine operating conditions which are the surrogates for the flight cycles. Previously, aircraft plumes were sampled in order to quantify VOCs by a proton transfer reaction quadrupole mass spectrometer (PTR-MS) [3]. This earlier study provided a preliminary knowledge on the emission of species such as methanol, acetaldehyde, acetone, benzene and toluene by varying engine thrust levels. The new setup was (i) designed to sample from the diluted engine exhaust and the new tool and (ii) used a high resolution time of flight PTR-MS with higher accuracy for many new species, therefore providing a more detailed and accurate inventory. We will present the emission factors for species that were quantified previously, as well as for many additional VOCs detected during the campaign

  20. Behavior of VOCs and carbonyl compounds emission from different types of wallpapers in Korea.

    Science.gov (United States)

    Lim, Jungyun; Kim, Suejin; Kim, Arong; Lee, Wooseok; Han, Jinseok; Cha, Jun-Seok

    2014-04-17

    Emissions of volatile organic compounds (VOCs) and carbonyls from three types of commercially available wallpapers (i.e., PVC-coated, paper-backed, natural material-coated) in Korea were evaluated using a 20 L small chamber. A total of 332 products were tested for emission factors, frequencies of occurrence and composition ratios. Toluene and formaldehyde concentrations were below Korean standard values for all products; however, the total VOC (TVOC) concentrations exceeded current standards (4.0 mg/m²·h) for 30 products. The TVOC emission factor for PVC-coated wallpapers, for which polymer materials are used in the manufacturing process, was seven and 16 times higher than those of paper-backed and natural material-coated wallpapers, respectively. The detection frequencies for toluene and formaldehyde were the highest (82.5%) and fourth highest (79.5%), respectively among the 50 target chemical species. The composition ratios for BTEX ranged from 0.3% to 5.1% and unidentified VOCs, which were not qualitatively analyzed using standard gas methods, ranged from 90.2% to 94.8%. Among six carbonyl compounds (acrolein was not detected in any type of wallpaper), acetone had the highest concentrations in PVC-coated (44.6%) and paper-backed (66.6%) wallpapers. Formaldehyde emissions were highest (64.6%) for natural material-coated wallpapers, a result of the formaldehyde-based resin used in the manufacturing process for these products.

  1. Effects of inhalation exposure to a binary mixture of benzene and toluene on vitamin a status and humoral and cell-mediated immunity in wild and captive American kestrels.

    Science.gov (United States)

    Olsgard, Mandy L; Bortolotti, Gary R; Trask, Brenda R; Smits, Judit E G

    2008-01-01

    Benzene and toluene are representative volatile organic compounds (VOC) released during production, storage, and transportation associated with the oil and gas industry and are chemicals of concern, as they are released in greater and possibly more biologically significant concentrations than other compounds. Most studies of air pollution in high oil and gas activity areas have neglected to consider risks to birds, including top-level predators. Birds can be used as highly sensitive monitors of air quality and since the avian respiratory tract is physiologically different from a rodent respiratory tract, effects of gases cannot be safely extrapolated from rodent studies. Wild and captive male American kestrels were exposed for approximately 1 h daily for 28 d to high (rodent lowest-observed-adverse-effect level [LOAEL] of 10 ppm and 80 ppm, respectively) or environmentally relevant (0.1 ppm and 0.8 ppm, respectively) levels of benzene and toluene. Altered immune responses characteristic of those seen in mammalian exposures were evident in kestrels. A decreased cell-mediated immunity, measured by delayed-type hypersensitivity testing, was evident in all exposed birds. There was no effect on humoral immunity. Plasma retinol levels as measured by high-performance liquid chromatography (HPLC) analysis were decreased in wild and captive kestrels exposed to the rodent LOAEL for combined benzene and toluene. This study indicates that American kestrels are sensitive to combined benzene and toluene. The study also illustrates the need for reference concentrations for airborne pollutants to be calculated, including sensitive endpoints specific to birds. Based on these findings, future studies need to include immune endpoints to determine the possible increased susceptibility of birds to inhaled toxicants.

  2. Toluene in alveolar air during controlled exposure to constant and to varying concentrations

    DEFF Research Database (Denmark)

    Bælum, Jesper

    1990-01-01

    The concentration of toluene in the alveolar air was measured in 20 males and 17 females exposed for 7 h either to a constant exposure to 100 ppm toluene or to a varying exposure with the same time-weighted average, but with peaks of 300 ppm every 30 min. Both exposure schedules included 50 to 10...

  3. Removal of Toluene at Low Concentration with Activated Carbon Filter : Adsorption Analysis using Tenax Tube and TD-GCMSD

    OpenAIRE

    Shan, Chi-En

    2016-01-01

    Various studies have demonstrated the usefulness of adsorption of activated carbon on VOCs removal. Large porosity and high adsorption allows activated carbon to remove very small particles. This project was commissioned by the company name Genano Oy to test the activated carbon filter in their air purifier and hence to provide a database for the company. The purpose of this thesis was to study the effectiveness of impregnated activated carbon filter on toluene removal. Experiment was co...

  4. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    Science.gov (United States)

    Chan, Ming-Huan; Chung, Shiang-Sheng; Stoker, Astrid K; Markou, Athina; Chen, Hwei-Hsien

    2012-01-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-d-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. PMID:23067721

  5. Rhodococcus aetherivorans IAR1, a new bacterial strain synthesizing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from toluene.

    Science.gov (United States)

    Hori, Katsutoshi; Kobayashi, Atsushi; Ikeda, Hiroshi; Unno, Hajime

    2009-02-01

    Toluene is the volatile organic compound (VOC) that is most abundantly emitted to the environment. Here, we report a new bacterial strain, IAR1, which synthesizes polyhydroxyalkanoate (PHA) from toluene as the sole carbon source. Using physiological tests and phylogenetic analysis, IAR1 was identified as Rhodococcus aetherivorans. Degradation of toluene by resting IAR1 cells followed Michaelis-Menten kinetics. The determined kinetic parameters showed that the degradation ability of IAR1 is slightly lower than that of Acinetobacter sp. Tol 5, which is highly effective for removing toluene from off-gas. PHA synthesized by IAR1 was identified as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by 1H NMR and gas chromatography. During fed-batch cultivation of resting IAR1 cells, the principal monomer unit shifted from 3-hydroxybutyrate to 3-hydroxyvalerate. PHBV shows flexibility and toughness comparable to conventional thermoplastics, but its production usually requires supplying expensive precursors as a secondary carbon source. Therefore, employment of R. aetherivorans IAR1 in the production of PHBV from toluene as the sole carbon source is an attractive means for production of the practical copolymer. In addition, the utilization of waste toluene as a raw material for the polymer production will achieve further cost reduction alongside the effective utilization of waste material.

  6. The aromatic volatile organic compounds toluene, benzene and styrene induce COX-2 and prostaglandins in human lung epithelial cells via oxidative stress and p38 MAPK activation.

    Science.gov (United States)

    Mögel, Iljana; Baumann, Sven; Böhme, Alexander; Kohajda, Tibor; von Bergen, Martin; Simon, Jan-Christoph; Lehmann, Irina

    2011-10-28

    Toluene, benzene and styrene are volatile organic compounds (VOCs) widely distributed in the environment. Tobacco smoke, traffic exposure and solvents used for paints, rubber and adhesives are known sources for these compounds. The aim of the present study was to investigate whether toluene, benzene and styrene can induce inflammatory reactions in lung cells and to characterize possible underlying mechanisms. A previous study gave evidence that expression of cyclooxygenase-2 (COX-2) is upregulated following exposure to the aromatic VOC chlorobenzene. Here, we investigated the effects of the aromatics toluene, benzene and styrene on human lung cells, with emphasis on COX-2, the rate-limiting enzyme of the prostaglandin pathway. In addition, we studied the potential role of oxidative stress and p38 MAPK activation in the toluene/benzene/styrene-dependent COX-2 induction. Following exposure to the aromatic compounds the expression level of COX-2 increased markedly. In addition, prostaglandin E(2) (PGE(2)) and prostaglandin F(2α) (PGF(2α)), major products of the COX enzyme, were found to be upregulated in response to toluene, benzene or styrene exposure. Furthermore, we observed an activation of p38 MAPK resulting from aromatic VOC exposure. Treatment of the cells with a specific p38 inhibitor (SB203580) or the antioxidant N-acetylcysteine (NAC) was able to prevent the toluene/benzene/styrene-dependent COX-2 activation, and subsequent increased PGE(2) and PGF(2α) secretion. These results suggest that toluene, benzene and styrene induce production and secretion of PGE(2) and PGF(2α) in lung epithelial cells via p38 MAPK and COX-2 activation in a redox sensitive manner. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  7. Heterogeneous photocatalysis of aromatic and chlorinated volatile organic compounds (VOCs) for non-occupational indoor air application.

    Science.gov (United States)

    Jo, Wan-Kuen; Park, Kun-Ho

    2004-11-01

    The current study evaluated the technical feasibility of applying TiO2 photocatalysis to the removal of low-ppb concentrations of volatile organic compounds (VOCs) commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) for VOCs, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) in relation to the PCO destruction efficiencies of the selected target VOCs. None of the target VOCs exhibited any significant dependence on the RH, which is inconsistent with a previous study where, under conditions of low humidity and a ppm toluene inlet level, a drop in the PCO efficiency was reported with a decreasing humidity. However, the other four parameters (HD, RM, FT, and IPS) were found to be important for better VOC removal efficiencies as regards the application of TiO2 photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VOCs at concentrations associated with non-occupational indoor air quality issues was up to nearly 100%, and the CO generated during PCO was a negligible addition to indoor CO levels. Accordingly, a PCO reactor would appear to be an important tool in the effort to improve non-occupational indoor air quality.

  8. 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.

  9. Developmental neurotoxicity after toluene inhalation exposure in rats

    DEFF Research Database (Denmark)

    Hass, Ulla; Lund, Søren Peter; Hougaard, Karin Sørig

    1999-01-01

    Rats were exposed to 1200 ppm or 0 ppm toluene (CAS 108-88-3) for 6 h per day from day 7 of pregnancy until day 18 postnatally. Developmental and neurobehavioral effects in the offspring were investigated using a test battery including assessment of functions similar to those in the proposed OECD...

  10. Benzene, toluene and xylene (BTX) pollution in ambient air: a case study.

    Science.gov (United States)

    Deole, Sarika; Phadke, K M; Kumar, Animesh

    2004-01-01

    Volatile Organic Compounds (VOCs) in presence of sunlight and oxides of nitrogen in atmosphere are considered as precursors for ozone production at the ground level. Concentration of Benzene, Toluene and Xylene (BTX) in ambient air was measured near seven traffic junctions in the city of Nagpur. Air samples were collected using Organic Vapour Sampler and analyzed by Gas Chromatograph equipped with Flame Ionization Detector (FID). Benzene concentration was found to be in the range 9.3 to 28.7 microg/m3, Toluene 3.26 to 21.0 microg/m3 and Xylene 4.9 to 15.0 microg/m3. These values are lower than those found in Metropolitan cities like Mumbai.

  11. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

    Science.gov (United States)

    Zhu, Yazhong; Luo, Yimeng; Ma, Hongye; Wang, Yan

    2016-01-01

    A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m3. The maximum elimination capacity of 36.0 g/(m3 h) occurred at an inlet loading rate of 45.9 g/(m3 h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs. PMID:27231662

  12. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

    Directory of Open Access Journals (Sweden)

    Yazhong Zhu

    2016-05-01

    Full Text Available A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m3. The maximum elimination capacity of 36.0 g/(m3 h occurred at an inlet loading rate of 45.9 g/(m3 h. The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m, for treating air streams containing VOCs.

  13. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior.

    Science.gov (United States)

    Zhu, Yazhong; Li, Shunyi; Luo, Yimeng; Ma, Hongye; Wang, Yan

    2016-01-01

    A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m(3). The maximum elimination capacity of 36.0 g/(m(3) h) occurred at an inlet loading rate of 45.9 g/(m(3) h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs.

  14. Anticonvulsant and antipunishment effects of toluene.

    Science.gov (United States)

    Wood, R W; Coleman, J B; Schuler, R; Cox, C

    1984-08-01

    Toluene can have striking acute behavioral effects and is subject to abuse by inhalation. To determine if its actions resemble those of drugs used in the treatment of anxiety ("anxiolytics"), two sets of experiments were undertaken. Inasmuch as prevention of pentylenetetrazol-induced convulsions is an identifying property of this class of agents, we first demonstrated that pretreatment with injections of toluene delayed the onset of convulsive signs and prevented the tonic extension phase of the convulsant activity in a dose-related manner. Injections of another alkyl benzene, m-xylene, were of comparable potency to toluene. Inhalation of toluene delayed the time to death after pentylenetetrazol injection in a manner related to the duration and concentration of exposure; at lower convulsant doses, inhalation of moderate concentrations (EC50, 1311 ppm) prevented death. Treatment with a benzodiazepine receptor antagonist (Ro 15-1788) failed to reduce the anticonvulsant activity of inhaled toluene. Anxiolytics also attenuate the reduction in response rate produced by punishment with electric shock. Toluene increased rates of responding suppressed by punishment when responding was maintained under a multiple fixed-interval fixed-interval punishment schedule of reinforcement. Distinct antipunishment effects were observed after 2 hr of exposure to 1780 and 3000 ppm of toluene; the rate-increasing effects of toluene were related to concentration and to time after the termination of exposure. Thus, toluene and m-xylene resemble in several respects clinically useful drugs such as the benzodiazepines.

  15. Methanogenic toluene metabolism: community structure and intermediates.

    Science.gov (United States)

    Fowler, S Jane; Dong, Xiaoli; Sensen, Christoph W; Suflita, Joseph M; Gieg, Lisa M

    2012-03-01

    Toluene is a model compound used to study the anaerobic biotransformation of aromatic hydrocarbons. Reports indicate that toluene is transformed via fumarate addition to form benzylsuccinate or by unknown mechanisms to form hydroxylated intermediates under methanogenic conditions. We investigated the mechanism(s) of syntrophic toluene metabolism by a newly described methanogenic enrichment from a gas condensate-contaminated aquifer. Pyrosequencing of 16S rDNA revealed that the culture was comprised mainly of Clostridiales. The predominant methanogens affiliated with the Methanomicrobiales. Methane production from toluene ranged from 72% to 79% of that stoichiometrically predicted. Isotope studies using (13)C(7) toluene showed that benzylsuccinate and benzoate transiently accumulated revealing that members of this consortium can catalyse fumarate addition and subsequent reactions. Detection of a BssA gene fragment in this culture further supported fumarate addition as a mechanism of toluene activation. Transient formation of cresols, benzylalcohol, hydroquinone and methylhydroquinone suggested alternative mechanism(s) for toluene metabolism. However, incubations of the consortium with (18)O-H(2)O showed that the hydroxyl group in these metabolites did not originate from water and abiotic control experiments revealed abiotic formation of hydroxylated species due to reactions of toluene with sulfide and oxygen. Our results suggest that toluene is activated by fumarate addition, presumably by the dominant Clostridiales. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Effects of VOCs on herbaceous plants in an open-top chamber experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cape, J.N.; Leith, I.D.; Binnie, J.; Content, J.; Donkin, M.; Skewes, M.; Price, D.N.; Brown, A.R.; Sharpe, A.D

    2003-07-01

    Birdsfoot trefoil and broad-leaved dock were affected by VOCs. - A selection of herbaceous plants representing the ground flora around a typical chemical installation in the UK was exposed continuously for 7 weeks to a mixture of six VOCs (acetone, acetonitrile, dichloromethane, ethanol, methyl t-butyl ether and toluene) in open-top chambers. Exposure concentrations were based on predictions of atmospheric dispersion from a single source, at a distance of approximately 2 km. The effects of continuous exposure, representing a worst-case, were measured in terms of uncontrolled water loss from leaves, leaf wettability, chlorophyll content and fluorescence, dry matter production and detailed observations of changes in plant growth and phenology. There were significant effects of VOC exposure on seed production, leaf water content and photosynthetic efficiency in some plant species. Such effects may be detectable in vegetation close to major industrial point sources of VOCs, or as a result of an accidental release of material during manufacture or transport. Some of the species tested e.g. birdsfoot trefoil (Lotus corniculatus L.) seem to be promising as potential bioindicators for VOCs, but there may be other even more sensitive species waiting to be discovered. However, the most obvious and conveniently measured response to VOC exposure in the birdsfoot trefoil (premature senescence i.e. advanced timing of seed pod production) could easily be confused in the field with climatic influences. It is also uncertain at this stage whether any of the effects observed would lead to longer term ecological changes in natural plant communities, through biased competition between sensitive and more tolerant species.

  17. Effect of continuous ozone injection on performance and biomass accumulation of biofilters treating gaseous toluene.

    Science.gov (United States)

    Xi, Jinying; Saingam, Prakit; Gu, Feng; Hu, Hong-Ying; Zhao, Xuefei

    2014-11-01

    Biofilters treating high-concentration gaseous volatile organic compounds (VOC) can be subject to bed clogging induced by excess biomass accumulation. In this study, O3 was continuously injected into biofilters to control biomass. Its effects on the performance of the biofilters and on biomass accumulation were investigated. Four identical biofilters designed to treat gaseous toluene were operated for 70 days, and three of them were continuously injected with O3 at different concentrations (from 80 to 320 mg/m(3)). The results showed that continuous O3 injection could effectively keep the bed pressure drop stable and had no adverse effect on toluene removal when O3 concentrations were 180-220 mg/m(3). The maximum toluene elimination capacity of the four biofilters was 140 g-toluene/m(3)/h, and the bed pressure drop of the biofilter fed with 180-220 mg/m(3) O3 remained below 3 mmH2O/m throughout the operation period. The biomass accumulation rates of the three biofilters with O3 at 80-320 mg/m(3) were lowered by 0.15-0.25 g/L/day compared with the biofilter without O3. The decreases in biomass accumulation resulted in higher void fractions of the filter beds with O3 injection. Carbon balance analysis indicated that CO2 production had increased while biomass accumulation and leachate waste production decreased in response to O3 injection. Based on the experimental results, it was concluded here that continuous O3 injection can reduce increases in bed pressure effectively, preserve VOC removal capacity, and prevent production of extra leachate waste.

  18. Effect of continuous ozone injection on performance and biomass accumulation of biofilters treating gaseous toluene.

    Science.gov (United States)

    Xi, Jinying; Saingam, Prakit; Gu, Feng; Hu, Hong-Ying; Zhao, Xuefei

    2015-01-01

    Biofilters treating high-concentration gaseous volatile organic compounds (VOC) can be subject to bed clogging induced by excess biomass accumulation. In this study, O3 was continuously injected into biofilters to control biomass. Its effects on the performance of the biofilters and on biomass accumulation were investigated. Four identical biofilters designed to treat gaseous toluene were operated for 70 days, and three of them were continuously injected with O3 at different concentrations (from 80 to 320 mg/m(3)). The results showed that continuous O3 injection could effectively keep the bed pressure drop stable and had no adverse effect on toluene removal when O3 concentrations were 180-220 mg/m(3). The maximum toluene elimination capacity of the four biofilters was 140 g-toluene/m(3)/h, and the bed pressure drop of the biofilter fed with 180-220 mg/m(3) O3 remained below 3 mmH2O/m throughout the operation period. The biomass accumulation rates of the three biofilters with O3 at 80-320 mg/m(3) were lowered by 0.15-0.25 g/L/day compared with the biofilter without O3. The decreases in biomass accumulation resulted in higher void fractions of the filter beds with O3 injection. Carbon balance analysis indicated that CO2 production had increased while biomass accumulation and leachate waste production decreased in response to O3 injection. Based on the experimental results, it was concluded here that continuous O3 injection can reduce increases in bed pressure effectively, preserve VOC removal capacity, and prevent production of extra leachate waste.

  19. VOC emissions of smouldering combustion from Mediterranean wildfires in central Portugal

    Science.gov (United States)

    Evtyugina, Margarita; Calvo, Ana Isabel; Nunes, Teresa; Alves, Célia; Fernandes, Ana Patrícia; Tarelho, Luís; Vicente, Ana; Pio, Casimiro

    2013-01-01

    Emissions of trace gases and C5-C10 volatile organic compounds (VOCs) from Mediterranean wildfires occurring in Portugal in summer 2010 were studied. Fire smoke was collected in Tedlar bags and analysed for CO, CO2, total hydrocarbons (THC) and VOCs. The CO, CO2 and THC emission factors (EFs) were 206 ± 79, 1377 ± 142 and 8.1 ± 9 g kg-1 biomass burned (dry basis), respectively. VOC emissions from Mediterranean wildfires were reported for the first time. Aromatic hydrocarbons were major components of the identified VOC emissions. Among them, benzene and toluene were dominant compounds with EFs averaging 0.747 ± 0.303 and 0.567 ± 0.422 g kg-1 biomass burned (dry basis), respectively. Considerable amounts of oxygenated organic volatile compounds (OVOCs) and isoprenoids were detected. 2-Furaldehyde and hexanal were the most abundant measured OVOCs with EFs of 0.337 ± 0.259 and 0.088 ± 0.039 g kg-1 biomass burned (dry basis), respectively. The isoprenoid emissions were dominated by isoprene (EF = 0.207 ± 0.195 g kg-1 dry biomass burned) and α-pinene (EF = 0.112 ± 0.093 g kg-1 dry biomass burned). Emission data obtained in this work are useful for validating and improving emission inventories, as well for carrying out modelling studies to assess the effects of vegetation fires on air pollution and tropospheric chemistry.

  20. 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.

  1. VOC signatures from North American oil and gas sources (Invited)

    Science.gov (United States)

    Simpson, I. J.; Marrero, J.; Blake, N. J.; Barletta, B.; Hartt, G.; Meinardi, S.; Schroeder, J.; Apel, E. C.; Hornbrook, R. S.; Blake, D. R.

    2013-12-01

    Between 2008 and 2013 UC Irvine has used its whole air sampling (WAS) technique to investigate VOC source signatures from a range of oil and gas sources in North America, including five separate field campaigns at the Alberta oil sands (1 airborne, 4 ground-based); the 2010 Deepwater Horizon oil spill (airborne and ship-based); the 2012 airborne Deep Convective Clouds and Chemistry Project (DC3) mission over oil and gas wells in Colorado, Texas and Oklahoma; and the 2013 ground-based Barnett Shale Campaign in Texas. Each campaign has characterized more than 80 individual C1-C10 VOCs including alkanes, alkenes and aromatics. For example, oil sands are an extra-heavy, unconventional crude oil that is blended with diluent in order to flow, and upgraded into synthetic crude oil. The VOC signature at the oil sands mining and upgrading facilities is alkane-rich, and the fuel gas associated with these operations has an i-butane/n-butane ratio similar to that of liquefied petroleum gas (LPG). In addition to light alkanes, enhanced levels of benzene were observed over US oil and natural gas wells during DC3, likely because of its use in hydrofracking fluid. A series of VOC emission ratios from North American petrochemical sources will be presented and compared, including oil sands, conventional oil and hydrofracking operations.

  2. Organic liquids storage tanks volatile organic compounds (VOCS) emissions dispersion and risk assessment in developing countries: the case of Dar-es-Salaam City, Tanzania.

    Science.gov (United States)

    Jackson, Msafiri M

    2006-05-01

    . Emission rates for benzene, toluene, and xylene were used as input to CALPUFF air dispersion model for the calculation of spatial downwind concentrations from area sources. By using global positioning system (GPS) and geographical information system (GIS) the spatial benzene concentration contributed by organic liquid storage tanks has been mapped for Dar-es-Salaam City. Highest concentrations for all the three toxic pollutants were observed at Kigamboni area, possibly because the area is located at the wind prevailing direction from the locations of the storage tanks. The model predicted concentrations downwind from the sources were below tolerable concentrations by WHO and US-OSHA. The highest 24 hrs averaging time benzene concentration was used for risk assessment in order to determine maximum carcinogenic risk amongst the population exposed at downwind. Established risk for adult and children at 2.9x10(-3) and 1.9x10(-3) respectively, are higher than the acceptable US-EPA risk of 1x10(-6). It is very likely that the actual VOCs concentrations in some urban areas in Tanzania including Dar-es-Salaam City are much higher than the levels reported in this study when other sources such as petrol stations and motor vehicles on the roads are considered. Tanzania Government therefore need to put in place: an air quality policy and legislation, establish air quality guidelines and acquire facilities which will enable the implementation of air quality monitoring and management programmes.

  3. Synergetic effect between adsorption and photodegradation on nanostructured TiO2/activated carbon fiber felt porous composites for toluene removal.

    Science.gov (United States)

    Li, Min; Lu, Bin; Ke, Qin-Fei; Guo, Ya-Jun; Guo, Ya-Ping

    2017-03-15

    The low quantum efficiency and limited adsorption efficiency of TiO2 makes it only fit for the removal of VOCs with low concentrations. Herein, we for the first time fabricated nanostructured TiO2/activated carbon fiber felt (TiO2/ACFF) porous composites by the in situ deposition of TiO2 microspheres on the carbon fibers in ACFF. Interestingly, the TiO2 microspheres exhibit hierarchical nanostructures constructed by nanocrystals as building blocks. The TiO2/ACFF porous composites possess excellent adsorption and photodegradation properties for toluene because of the synergetic effects between the nanostructured TiO2 and ACFF. The adsorption efficiencies of the TiO2/ACFF porous composites reach approximately 98% at the toluene concentration (TiO2/ACFF porous composites significantly enhances photocatalytic property for toluene by hindering the recombination of electron-hole pairs, reducing the TiO2 band gap energy (Eg) to 2.95eV and accelerating toluene adsorption. At the toluene concentrations of 230ppm and 460ppm, the photocatalytic oxidation efficiency of toluene into CO2 arrives at 100% and 81.5%, respectively. Therefore, the TiO2/ACFF porous composites with synergetic adsorption and photocatalytic activities have great potentials for toluene removal.

  4. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    Hougaard, Karin S; Hansen, Åse Marie; Hass, Ulla

    2003-01-01

    of corticosteroids from the maternal to the foetal compartment. Pregnant rats were subjected to either 1500 ppm toluene 6 hr/day and/or a schedule of "Chronic mild stress" during the last two weeks of gestation. Exposure to toluene was associated with reduced birth weight and lower maternal weight gain, the latter...

  5. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    Hougaard, K. S.; Hansen, A. M.; Hass, Ulla

    2003-01-01

    Combined exposure to stressors and chemicals may result in synergistic effects. The effects of prenatal exposure to the organic solvent toluene resemble those observed in offspring of gestationally stressed dams, a possible common mechanism being transfer of stress-/toluene-induced increments of ...

  6. Toluene in alveolar air during controlled exposure to constant and to varying concentrations

    DEFF Research Database (Denmark)

    Bælum, Jesper

    1990-01-01

    The concentration of toluene in the alveolar air was measured in 20 males and 17 females exposed for 7 h either to a constant exposure to 100 ppm toluene or to a varying exposure with the same time-weighted average, but with peaks of 300 ppm every 30 min. Both exposure schedules included 50 to 100...... W exercise in three 15-min periods. Repetitive measurements of the toluene concentrations in the alveolar air were made in two 30-min periods, one at rest and one including work. At rest the alveolar concentration increased rapidly in response to an increase in the inspiratory air concentration...

  7. Toluene depresses plasma corticosterone in pregnant rats

    DEFF Research Database (Denmark)

    Hougaard, Karin S; Hansen, Åse Marie; Hass, Ulla

    2003-01-01

    Combined exposure to stressors and chemicals may result in synergistic effects. The effects of prenatal exposure to the organic solvent toluene resemble those observed in offspring of gestationally stressed dams, a possible common mechanism being transfer of stress-/toluene-induced increments...... of corticosteroids from the maternal to the foetal compartment. Pregnant rats were subjected to either 1500 ppm toluene 6 hr/day and/or a schedule of "Chronic mild stress" during the last two weeks of gestation. Exposure to toluene was associated with reduced birth weight and lower maternal weight gain, the latter...... being enhanced by maternal stress. A depressant effect of toluene on maternal corticosterone was observed, hence the study does not provide immediate evidence that transfer of elevated levels of corticosterone from the maternal to the foetal compartment mediates the effects of prenatal exposure...

  8. Identification of toluene degraders in a methanogenic enrichment culture.

    Science.gov (United States)

    Fowler, S Jane; Gutierrez-Zamora, Maria-Luisa; Manefield, Mike; Gieg, Lisa M

    2014-09-01

    Methanogenic biodegradation involves the cooperative metabolism of syntrophic bacteria that catalyse the initial attack and subsequent degradation of hydrocarbons, and methanogens that convert intermediates such as hydrogen and carbon dioxide, formate, and/or acetate to methane. The identity of syntrophic microbes and the nature of their interactions with other syntrophs and methanogens are not well understood. Furthermore, it is difficult to isolate the organisms responsible for the initial activation and subsequent degradation of hydrocarbon substrates under methanogenic conditions due to the thermodynamic relationships that exist among microbes in methanogenic communities. We used time-resolved RNA stable isotope probing and RT-qPCR to identify the organisms involved in the initial attack on toluene and subsequent degradation reactions in a highly enriched toluene-degrading methanogenic culture. Our results reveal the importance of a Desulfosporosinus sp. in anaerobic toluene activation in the culture. Other organisms that appear to play roles in toluene degradation include Syntrophaceae, Desulfovibrionales and Chloroflexi. The high bacterial diversity observed in this culture and the extensive labelling of different phylogenetic groups over the course of the stable isotope probing experiment highlight the complexity of the relationships that exist in methanogenic ecosystems. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. Characteristics of volatile organic compounds (VOCs) from the evaporative emissions of modern passenger cars

    Science.gov (United States)

    Yue, Tingting; Yue, Xin; Chai, Fahe; Hu, Jingnan; Lai, Yitu; He, Liqang; Zhu, Rencheng

    2017-02-01

    Volatile organic compounds (VOCs) from vehicle evaporative emissions contribute substantially to photochemical air pollution. Yet, few studies of the characteristics of VOCs emitted from vehicle evaporative emissions have been published. We investigate the characteristics of 57 VOCs in hot soak, 24 h diurnal and 48 h diurnal emissions by applying the Sealed Housing Evaporative Determination unit (SHED) test to three modern passenger cars (one US Tier 2 and two China IV vehicles) using two different types of gasoline. The characteristics of the VOCs from the hot soak, 24 h diurnal and 48 h diurnal emissions were different due to their different emission mechanisms. In the hot soak emissions, toluene, isopentane/n-pentane, and 2,2,4-trimethylpentane were dominant species. In the 24 h and 48 h diurnal emissions, isopentane and n-pentane were dominant species. Toluene was the third most dominant component in the 24 h diurnal emissions but decreased by a mass of 42%-80% in the 48 h diurnal emissions. In the hot soak, 24 h diurnal and 48 h diurnal emissions, alkanes were generally the dominant hydrocarbons, followed by aromatics and olefins. However, owing to different evaporative emission mechanisms, the weight percentages of the aromatic hydrocarbons decreased and the weight percentages of the alkanes increased from the hot soak test to the 24 h diurnal and 48 h diurnal tests for each vehicle. The dominant contributors to the ozone formation potentials (OFPs) were also different in the hot soak, 24 h diurnal and 48 h diurnal emissions. The OFPs (g O3/g VOC) of the hot soak emissions were higher than those of the 24 h and 48 h diurnal emissions. In addition, the combined effect of decreasing the olefin and aromatic contents of gasoline on vehicle evaporative emissions was investigated. The aromatics all decreased substantially in the hot soak, 24 h and 48 h diurnal emissions, and the total masses of the VOCs and OFPs decreased, with the greatest reduction occurring in

  10. 688 AMBIENT VOLATILE ORGANIC COMPOUNDS (VOCS ...

    African Journals Online (AJOL)

    Osondu

    The VOCs were classified thus: aromatics 41%, halogenated 42%, esters 3%, ketones 8%, ... and Industrial emission were identified as sources of VOCs in the studied industrial area with ... canisters, or by dynamic or diffusive adsorption .... The GC/FID was standardized and ... with CS2 was prepared from stock standard in.

  11. DEVELOPING A NO-VOC WOOD TOPCOAT

    Science.gov (United States)

    The paper reports an evaluation of a new low-VOC (volatile organic compound) wood coating technology, its performance characteristics, and its application and emissions testing. The low-VOC wood coating selected for the project was a two-component, water-based epoxy coating. Poly...

  12. 长江三角洲地区基于喷涂工艺的溶剂源 VOCs 排放特征%Process-based Emission Characteristics of Volatile Organic Compounds(VOCs) from Paint Industry in the Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    莫梓伟; 牛贺; 陆思华; 邵敏; 勾斌

    2015-01-01

    了解挥发性有机物(volatile organic compounds,VOCs)的溶剂源排放特征是制定长江三角洲地区 PM2.5和臭氧防控策略的关键.本研究通过罐采样-GC-MS/ FID 测定了长江三角洲地区重点喷涂行业(集装箱喷涂、造船喷涂、木器喷涂和汽车喷涂业)的 VOCs 排放特征.结果表明,长江三角洲地区喷涂行业排放的主要 VOCs 组分为甲苯、二甲苯、乙苯等芳香烃类物质,三者之和占总 VOCs 的质量分数为79%~99%.生产工艺的不同对 VOCs 的排放组成影响并不大,废气处理装置中活性炭吸附对 VOCs 的组成并无明显影响,而催化燃烧的处理过程会使 VOCs 的排放组成产生显著变化,乙烯排放明显增大,同时也使得催化燃烧处理最大增量反应活性(maximum increment reactivity,MIR)值高于活性炭吸附处理后的 MIR 值,说明不同的处理措施的使用将影响 VOCs 对臭氧的生成作用.%Understanding the volatile organic compounds (VOCs) emission characteristics from solvent usage industry is essential to reduce PM2. 5 and O3 in Yangtze River Delta region. In this work, VOCs source characteristics of ship container, shipbuilding, wood, and automobile painting industry were measured using canister-GC-MS/ FID analysis system. The results showed that VOCs emitted from these industrial sectors were mainly aromatics, such as toluene, xylene, and ethylbenzene, accounting for 79% - 99% of total VOCs. The VOCs treatment facilities of activated carbon adsorption had little impact on changing the composition patterns of VOCs, while catalytic combustion treatments produced more alkenes. The combustion treatment of VOCs changed the maximum increment reactivity (MIR) of the VOCs emissions, and was thus very likely to change the ozone formation potentials.

  13. [Index assessment of airborne VOCs pollution in automobile for transporting passengers].

    Science.gov (United States)

    Chen, Xiao-Kai; Cheng, He-Ming; Luo, Hui-Long

    2013-12-01

    Car for transporting passenger is the most common means of transport and in-car airborne volatile organic compounds (VOCs) cause harm to health. In order to analyze the pollution levels of benzene, toluene, ethylbenzene, xylenes, styrene and TVOC, index evaluation method was used according to the domestic and international standards of indoor and in-car air quality (IAQ). For Chinese GB/T 18883-2002 IAQ Standard, GB/T 17729-2009 Hygienic Standard for the Air Quality inside Long Distance Coach, GB/T 27630-2011 Guideline for Air Quality Assessment of Passenger Car, IAQ standard of South Korea, Norway, Japan and Germany, the heaviest pollution of VOCs in passenger car was TVOC, TVOC, benzene, benzene, TVOC, toluene and TVOC, respectively, the average pollution grade of automotive IAQ was median pollution, median pollution, clean, light pollution, median pollution, clean and heavy pollution, respectively. Index evaluation can effectively analyze vehicular interior air quality, and the result has a significant difference with different standards; German standard is the most stringent, while Chinese GB/T 18883-2002 standard is the relatively stringent and GB/T 27630-2011 is the most relaxed.

  14. 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.

  15. Relative vulnerability of public supply wells to VOC contamination in hydrologically distinct regional aquifers

    Science.gov (United States)

    Kauffman, L.J.; Chapelle, F.H.

    2010-01-01

    A process-based methodology was used to compare the vulnerability of public supply wells tapping seven study areas in four hydrologically distinct regional aquifers to volatile organic compound (VOC) contamination. This method considers (1) contributing areas and travel times of groundwater flowpaths converging at individual supply wells, (2) the oxic and/or anoxic conditions encountered along each flowpath, and (3) the combined effects of hydrodynamic dispersion and contaminant- and oxic/anoxic-specific biodegradation. Contributing areas and travel times were assessed using particle tracks generated from calibrated regional groundwater flow models. These results were then used to estimate VOC concentrations relative to an unspecified initial concentration (C/C0) at individual public supply wells. The results show that the vulnerability of public supply wells to VOC contamination varies widely between different regional aquifers. Low-recharge rates, long travel times, and the predominantly oxic conditions characteristic of Basin and Range aquifers in the western United States leads to lower vulnerability to VOCs, particularly to petroleum hydrocarbons such as benzene and toluene. On the other hand, high recharge rates and short residence times characteristic of the glacial aquifers of the eastern United States leads to greater vulnerability to VOCs. These differences lead to distinct patterns of C/C0 values estimated for public supply wells characteristic of each aquifer, information that can be used by resource managers to develop monitoring plans based on relative vulnerability, to locate new public supply wells, or to make land-use management decisions. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

  16. Anticonvulsant and antipunishment effects of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.W.; Coleman, J.B.; Schuler, R.; Cox, C.

    1984-01-01

    Toluene can have striking acute behavioral effects and is subject to abuse by inhalation. To determine if its actions resemble those of drugs used in the treatment of anxiety (anxiolytics), two sets of experiments were undertaken. Inasmuch as prevention of pentylenetetrazol-induced convulsions is an identifying property of this class of agents, the authors first demonstrated that pretreatment of mice with injections of toluene delayed the onset of convulsive signs and prevented the tonic extension phase of the convulsant activity in a dose-related manner. Injections of another alkyl benzene, m-xylene, were of comparable potency to toluene. Inhalation of toluene delayed the time of death after pentylenetetrazol injection in a manner related to the duration and concentration of exposure; at lower convulsant doses, inhalation of moderate concentrations (EC/sub 58/, 1300 ppm) prevented death. Treatment with a benzodiazepine receptor antagonist (Ro 15-1788) failed to reduce the anticonvulsant activity of inhaled toluene. Anxiolytics also attenuate the reduction in response rate produced by punishment with electric shock. Toluene increased rates of responding suppressed by punishment when responding was maintained under a multiple fixed-interval fixed-interval punishment schedule of reinforcement. Distinct antipunishment effects were observed in rats after 2 hr of exposure to 1780 and 3000 ppm of toluene; the rate-increasing effects of toluene were related to concentration and to time after the termination of exposure. Thus, toluene and m-xylene resemble in several respects clinically useful drugs such as the benzodiazepines. 51 references, 3 figures, 2 tables.

  17. 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

  18. CAN SORBENT-BASED GAS PHASE AIR CLEANING FOR VOCS SUBSTITUTE FOR VENTILATION IN COMMERCIAL BUILDINGS?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William; Fisk, William J.

    2007-08-01

    This paper reviews current knowledge about the suitability of sorbent-based air cleaning for removing volatile organic compounds (VOCs) from the air in commercial buildings, as needed to enable reductions in ventilation rates and associated energy savings. The principles of sorbent air cleaning are introduced, criteria are suggested for sorbent systems that can counteract indoor VOC concentration increases from reduced ventilation, major findings from research on sorbent performance for this application are summarized, and related priority research needs are identified. Major conclusions include: sorbent systems can remove a broad range of VOCs with moderate to high efficiency, sorbent technologies perform effectively when challenged with VOCs at the low concentrations present indoors, and there is a large uncertainty about the lifetime and associated costs of sorbent air cleaning systems when used in commercial buildings for indoor VOC control. Suggested priority research includes: experiments to determine sorbent system VOC removal efficiencies and lifetimes considering the broad range and low concentration of VOCs indoors; evaluations of in-situ regeneration of sorbents; and an updated analysis of the cost of sorbent air cleaning relative to the cost of ventilation.

  19. Biofiltration of wastewater lift station emissions: evaluation of VOC removal in the presence of H{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Alvaro; Rathibandla, Snehasheela; Jones, Kim; Cabezas, Jose [Texas A and M University-Kingsville, Department of Environmental Engineering, Kingsville, TX (United States)

    2008-02-15

    The capacity of biofilter systems to remove volatile organic compounds in the presence of high concentrations of hydrogen sulfide was investigated for applications in wastewater lift stations. The treatment system was an enclosed unit composed of a biotrickling filter coupled with a biofilter. The biofilter media were plastic hollow spherical balls filled with a compost mixture; and the biotrickling filter media was a structured plastic packing. The gases from the pumping station wet well were a mixture of H{sub 2}S and low concentration aliphatic and aromatic VOCs, toluene being the most significant in concentrations of 41 ppb. The H{sub 2}S concentration was 314 ppm with fluctuations of 100 ppm resulting from pumping cycles at the station. No inhibition effect was detected from the simultaneous biological removal of VOCs and H{sub 2}S: toluene removal efficiency was 91% with the two sections contributing approximately equally to the pollutant removal; and the average removal of H{sub 2}S was 74%. A traditional open-in-ground biofilter filled with wood chips and compost, existing in the site, attained similar removal efficiencies for toluene, but the elimination capacity of the biotrickling/biofilter system was 3.3-times higher than the open biofilter. (orig.)

  20. Toluene inhalation in adolescent rats reduces flexible behaviour in adulthood and alters glutamatergic and GABAergic signalling.

    Science.gov (United States)

    Furlong, Teri M; Duncan, Jhodie R; Corbit, Laura H; Rae, Caroline D; Rowlands, Benjamin D; Maher, Anthony D; Nasrallah, Fatima A; Milligan, Carol J; Petrou, Steven; Lawrence, Andrew J; Balleine, Bernard W

    2016-12-01

    Toluene is a commonly abused inhalant that is easily accessible to adolescents. Despite the increasing incidence of use, our understanding of its long-term impact remains limited. Here, we used a range of techniques to examine the acute and chronic effects of toluene exposure on glutameteric and GABAergic function, and on indices of psychological function in adult rats after adolescent exposure. Metabolomics conducted on cortical tissue established that acute exposure to toluene produces alterations in cellular metabolism indicative of a glutamatergic and GABAergic profile. Similarly, in vitro electrophysiology in Xenopus oocytes found that acute toluene exposure reduced NMDA receptor signalling. Finally, in an adolescent rodent model of chronic intermittent exposure to toluene (10 000 ppm), we found that, while toluene exposure did not affect initial learning, it induced a deficit in updating that learning when response-outcome relationships were reversed or degraded in an instrumental conditioning paradigm. There were also group differences when more effort was required to obtain the reward; toluene-exposed animals were less sensitive to progressive ratio schedules and to delayed discounting. These behavioural deficits were accompanied by changes in subunit expression of both NMDA and GABA receptors in adulthood, up to 10 weeks after the final exposure to toluene in the hippocampus, prefrontal cortex and ventromedial striatum; regions with recognized roles in behavioural flexibility and decision-making. Collectively, our data suggest that exposure to toluene is sufficient to induce adaptive changes in glutamatergic and GABAergic systems and in adaptive behaviour that may underlie the deficits observed following adolescent inhalant abuse, including susceptibility to further drug-use. © 2016 International Society for Neurochemistry.

  1. Study on characteristics of double surface VOC emissions from dry flat-plate building materials

    Institute of Scientific and Technical Information of China (English)

    WANG Xinke; ZHANG Yinping; ZHAO Rongyi

    2006-01-01

    This paper sets up an analytic model of double surface emission of volatile organic compound (VOC) from dry, flat-plate building materials. Based on it, the influence of factors including air change rate, loading factor of materials in the room, mass diffusion coefficient, partition coefficient, convective mass transfer coefficient, thickness of materials, asymmetric convective flow and initial VOC concentration distribution in the building material on emission is discussed. The conditions for simplifying double surface emission into single surface emission are also discussed. The model is helpful to assess the double surface VOC emission from flat-plate building materials used in indoor furniture and space partition.

  2. Primary atmospheric oxidation mechanism for toluene.

    Science.gov (United States)

    Baltaretu, Cristian O; Lichtman, Eben I; Hadler, Amelia B; Elrod, Matthew J

    2009-01-08

    The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique at temperatures ranging from 228 to 298 K. A major dienedial-producing pathway was detected for the first time for toluene oxidation, and glyoxal and methylglyoxal were found to be minor primary oxidation products. The results suggest that secondary oxidation processes involving dienedial and epoxide primary products are likely responsible for previous observations of glyoxal and methylglyoxal products from toluene oxidation. Because the dienedial-producing pathway is a null cycle for tropospheric ozone production and glyoxal and methylglyoxal are important secondary organic aerosol precursors, these new findings have important implications for the modeling of toluene oxidation in the atmosphere.

  3. Impact of artificial waterfall using reclaimed water to VOCs and its health risk assessment

    Institute of Scientific and Technical Information of China (English)

    MA Jin-jun; ZHU Hong-liang; ZHAO San-ping; WANG Yong-jie; ZHU Yong-bing

    2008-01-01

    To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds(VOCs) in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic com-pounds (TOVCs) concentration of a background sample is 2112μg/m3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216μg/m3 and 6362μg/m3, which are 1.52-3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X (Benzene/Toluene/Ethylbenzene/Xylene) ratio of the air sample around the artificial water fall is(0.36/11.78/1/1.10). Health risk assessment (HRA) was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2.8-1.6times that of the background sample. However, the total risk value of the air sample around the waterfall (2.8×10-6) for common people is still lower, compared to the acceptable public risk level( 10-5). For occupation-al workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values(1.26×10-5) is higher than that of the acceptable public risk level.

  4. VOCs in industrial, urban and suburban neighborhoods—Part 2: Factors affecting indoor and outdoor concentrations

    Science.gov (United States)

    Jia, Chunrong; Batterman, Stuart; Godwin, Christopher

    Many microenvironmental and behavioral factors can affect concentrations of and exposures to volatile organic compounds (VOCs). Identifying these determinants is important to understand exposures and risks, and also to design policies and strategies that minimize concentrations. This study is aimed at determining factors associated with VOC concentrations found indoors in residences and outdoors in ambient air. It utilizes results from a comprehensive field study in which 98 VOCs were measured both inside and outside of 159 residences in three communities in southeast Michigan, USA. Additional measurements included indoor CO 2 concentrations, temperature, relative humidity, building and neighborhood characteristics, and occupant activities, assessed using a questionnaire and comprehensive walkthrough investigation. Factors potentially affecting concentrations were identified using bivariate and multivariate analyses. Outdoors, seasonal and community effects were observed. Indoors, seasonal effects were limited to the urban and industrial communities, largely due to changes in ambient levels. Elevated indoor VOC concentrations were associated with eight sources or activities: the presence of an attached garage; recent renovations; older residences; indoor smoking; less frequent window or door opening; higher CO 2 concentrations; and lower ventilation rates. VOC levels were uninfluenced by building materials (wood vs. brick), flooring type (carpeting vs. wood), stove type (gas or electric), number of occupants, air freshener use, and hobbies involving arts and crafts. Factor analyses identified up to five factors for the ambient VOC measurements, and up to 10 factors for the indoor measurements, which further helped to explain the variability of concentrations and associations between VOCs.

  5. 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.

  6. 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

    2017-01-01

    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. PMID:28117727

  7. Measurement and Correlation of Ambient VOCs in Windsor, Ontario, Canada and Detroit, Michigan, USA

    Science.gov (United States)

    Miller, L. J.; You, H.; Xu, X.; Molaroni, S.; Lemke, L.; Weglicki, L.; Krouse, H.; Krajenta, R.

    2009-05-01

    An air quality study has been carried out in Windsor, Ontario, Canada and Detroit, Michigan, USA as part of a pilot research study undertaken by the Geospatial Determinants of Health Outcomes Consortium (GeoDHOC), a multidisciplinary, international effort aimed at understanding the health effects of air pollution in urban environments. Exposure to volatile organic compounds has long been associated with adverse health conditions such as atrophy of skeletal muscles, loss of coordination, neurological damage, dizziness, throat, nose, and eye irritation, nervous system depression, liver damage, and respiratory symptoms. Twenty-six species of ambient volatile organic compounds (VOCs) were monitored during a 2-week period in September, 2008 at 100 sites across Windsor and Detroit, using 3M # 3500 Organic Vapour Monitors. Ten species with highest concentrations were selected for further investigation; Toluene (mean concentration =4.14 μm/m3), (m+p)-Xylene (2.30 μm/m3), Hexane (1.87 μm/m3), Benzene (1.37 μm/m3), 1,2,4-Trimethylbenzene (0.87 μm/m3), Dichloromethane (0.77 μm/m3), Ethylbenzene (0.68 μm/m3), o-Xylene (0.63 μm/m3), n-Decane (0.42 μm/m3), and 1,3,5-Trimethylbenzene (0.39 μm/m3). Comparison to a similar investigation in Sarnia, Ontario in October 2005 revealed that the mean concentrations of VOCs were higher in Windsor-Detroit for all species by a significant margin (31-958%), indicating substantial impact of local industrial and vehicular emissions in the WindsorVDetroit area. For most VOCs, the concentrations were higher in Detroit than in Windsor. The mean concentration of total VOC was 9.7 μm/m3 in Windsor, which is slightly higher than that in Sarnia in 2005 (7.9 um/m3), whilst total VOC concentration in Detroit was much higher (16.5 μm/m3). There were strong correlations among several of the 10 species, with the highest Pearson correlation coefficients (r=0.78 - 0.99, p<0.05) amongst the BTEX (benzene, toluene, ethylbenzene, and xylenes) group

  8. 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.

  9. Reduction of benzene toxicity by toluene.

    Science.gov (United States)

    Plappert, U; Barthel, E; Seidel, H J

    1994-01-01

    BDF1 mice were exposed in inhalation chambers to benzene (900 ppm, 300 ppm) and/or toluene (500 ppm, 250 ppm) 6 hr per day, 5 days per week, for up to 8 weeks. Benzene alone induced a slight anemia after 4 and 8 weeks and a reduction of BFU-E and CFU-E numbers in the marrow. The coexposure to toluene reduced the degree of anemia. These results confirm previous studies where toluene was found to reduce benzene toxicity. This protective effect was most pronounced when DNA damage was studied in peripheral blood cells, bone marrow, and liver using the single cell gel (SCG) assay. With benzene alone, either with 300 or 900 ppm, a significant increase in DNA damage was detected in cells sampled from all three organs. Toluene alone did not induce a significant increase in DNA damage. The coexposure of benzene and toluene reduced the extent of DNA damage to about 50% of benzene alone. This result is considered a clear indication for a protective effect of toluene on the genetic toxicity of benzene.

  10. Toluene-induced ototoxicity by subcutaneous administration

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, G.T.; Howd, R.A.

    1986-01-01

    Inhalation exposure of rats to toluene causes irreversible hearing loss (e.g., Pryor et al.). To determine whether noise emanating from the inhalation system was a major contributing factor and whether exposure by a noninhalation route would cause a similar effect, weanling, male Fischer-344 rats were injected SC twice daily in a quiet environment with PEG-300 (control) or with 1.5 or 1.7 g/kg of toluene for 7 days. After being trained to perform a multisensory conditioned avoidance response (CAR) task, tone intensity-response functions were generated at 4, 8, 12, and 20 kHz, and behavioral auditory response thresholds were estimated. Toluene caused a dose-related hearing loss at frequencies of 8 kHz and above, with no effect on performance of the CAR in response to light, nonaversive footshock, or the 4-kHz tone. The similarity of this effect to that observed following inhalation exposure indicates that noise is not a major factor in the toluene-induced hearing loss, although possible interactions between noise and toluene remain to be investigated. These results also demonstrate that direct penetration of the toluene vapors through the external ear structure, as might occur during inhalation exposure, is not a necessary condition for inducing the hearing loss.

  11. EVALUATION OF LOW-VOC LATEX PAINTS

    Science.gov (United States)

    The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that ...

  12. Locating industrial VOC sources with aircraft observations.

    Science.gov (United States)

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

    2011-05-01

    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.

  13. Safety Evaluation of Osun River Water Containing Heavy Metals and Volatile Organic Compounds (VOCs) in Rats.

    Science.gov (United States)

    Azeez, L; Salau, A K; Adewuyi, S O; Osineye, S O; Tijani, K O; Balogun, R O

    2015-12-20

    This study evaluated the pH, heavy metals and volatile organic compounds (VOCs) in Osun river water. It also evaluated its safety in rats. Heavy metals were determined by atomic absorption spectrophotometry (AAS) while VOCs were determined by gas chromatography coupled with flame ionization detector (GC-FID). Male and female rats were exposed to Osun river water for three weeks and then sacrificed. The abundance of heavy metals in Osun river followed the trend Pb > Cd > Zn > Fe > Cr > Cu while VOCs followed the trend benzene < ethylbenzene < toluene < xylene. The concentrations of Pb, Cd and benzene were higher than the permissible limits of Standards Organization of Nigeria (SON) and World Health Organization (WHO) respectively. Rats exposed to Osun river water for three weeks had increased WBC, thiobarbituric acid reactive substances (TBARS), serum proteins and serum aminotransferases. There were also significant decreases in HCT, PLT, liver aminotransferases and liver glutathione compared to the control. These results show that the pollutants in Osun river water are capable of inducing hematological imbalance and liver cell injury. The toxicity induced in blood was sex-dependent affecting female rats more than male rats.

  14. 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.

  15. VOC characteristics, emissions and contributions to SOA formation during hazy episodes

    Science.gov (United States)

    Sun, Jie; Wu, Fangkun; Hu, Bo; Tang, Guiqian; Zhang, Junke; Wang, Yuesi

    2016-09-01

    Volatile organic compounds (VOC) are important precursors of secondary organic aerosols (SOA). The pollution processes in Beijing were investigated from 18th October to 6th November 2013 to study the characteristics, SOA formation potential and contributing factors of VOC during hazy episodes. The mean concentrations of VOC were 67.4 ± 33.3 μg m-3 on clear days and have 5-7-fold increase in polluted periods. VOC concentrations rapidly increased at a visibility range of 4-5 km with the rate of 25%/km in alkanes, alkenes and halocarbons and the rate of 45%/km in aromatics. Analysis of the mixing layer height (MLH); wind speed and ratios of benzene/toluene (B/T), ethylbenzene/m,p-xylene (E/X), and isopentane/n-pentane (i/n) under different visibility conditions revealed that the MLH and wind speed were the 2 major factors affecting the variability of VOC during clear days and that local emissions and photochemical reactions were main causes of VOC variation on polluted days. Combined with the fractional aerosol coefficient (FAC) method, the SOA formation potentials of alkanes, alkenes and aromatics were 0.3 ± 0.2 μg m-3, 1.1 ± 1.0 μg m-3 and 6.5 ± 6.4 μg m-3, respectively. As the visibility deteriorated, the SOA formation potential increased from 2.1 μg m-3 to 13.2 μg m-3, and the fraction of SOA-forming aromatics rapidly increased from 56.3% to 90.1%. Initial sources were resolved by a positive matrix factorization (PMF) model. Vehicle-related emissions were an important source of VOC at all visibility ranges, accounting for 23%-32%. As visibility declined, emissions from solvents and the chemical industry increased from 13.2% and 6.3% to 34.2% and 23.0%, respectively. Solvents had the greatest SOA formation ability, accounting for 52.5% on average on hazy days, followed by vehicle-related emissions (20.7%).

  16. Low VOC Barrier Coating for Industrial Maintenance

    Science.gov (United States)

    2012-09-01

    Technology Certification Program HAP Hazardous Air Pollutant HW hazardous waste LVBC low VOC barrier coating MEK methyl ethyl ketone MIL-DTL...peeling, blistering , tape adhesion, pull-off adhesion, film thickness, and LVBC/ZVT patch test adhesion testing in an acceptable or better manner...significant reductions in the amount of hazardous waste generated by the Navy. The ZVT technology contains less than 5 g/l of VOC and the resulting

  17. Effect of toluene on fathead minnow (Pimephales promelas Rafinesque) development

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, E.W.; Brammer, J.D.; Puyear, R.L.

    1985-09-01

    The environmental levels of aromatic hydrocarbons present in freshwater systems have been poorly characterized. This study examines the effect of toluene, a major water-soluble component of petroleum fuels on teleost development under controlled conditions. The fathead minnow Pimephales promelas Rafinesque, was chosen as a model teleost for this study. Live embryos as well as serial sections of paraffin-embedded embryos were examined to determine effects of the toxicant. The toluene concentrations utilized ranged from 30 to 45 mg/L. Abnormalities noted under these conditions included distorted embryonic axis, abnormal heart and circulatory system development, hydration and swelling of the pericardial coelom, hemorrhaging an overall stunted appearance, microphthalmia, and a unique migration of the ventrally located yolk syncytial layer and its associated nuclei.

  18. CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX PAINT AND ALKYD PAINTS

    Science.gov (United States)

    The report gives details of a small-chamber test method developed by the EPA for characterizing volatile organic compound (VOC) emissions from interior latex and alkyd paints. Current knowledge about VOC, including hazardous air pollutant, emissions from interior paints generated...

  19. 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 tha

  20. Association analysis of toluene exposure time with high-throughput mRNA expressions and methylation patterns using in vivo samples.

    Science.gov (United States)

    Hong, Ji Young; Yu, So Yeon; Kim, Seol Young; Ahn, Jeong Jin; Kim, Youngjoo; Kim, Gi Won; Son, Sang Wook; Park, Jong-Tae; Hwang, Seung Yong

    2016-04-01

    The emission of volatile organic compounds (VOCs) resulting from outdoor air pollution can contribute to major public health problems. However, there has been limited research on the health effects in humans from the inhalation of VOCs. Therefore, this study conducted an in vivo analysis of the effects of toluene, one of the most commonly used chemicals in many industries, on gene expression and methylation over time using the high-throughput technique of microarray analysis. We separated participants into three groups (control, short-term exposure, and long-term exposure) to investigate the influence of toluene exposure time on gene expression. We then comprehensively analyzed and investigated the correlation between variations in gene expression and the occurrence of methylation. Twenty-six genes were upregulated and hypomethylated, while 32 genes were downregulated and hypermethylated. The pathways of these genes were confirmed to be associated with cell survival and the immune system. Based on our findings, these genes can help predict the effects of time-dependent exposure to toluene on human health. Thus, observations from our data may have implications for the identification of biomarkers of toluene exposure. Copyright © 2015. Published by Elsevier Inc.

  1. Characteristics and Source Apportionment of Volatile Organic Compounds (VOCs) in the Northern Suburb of Nanjing%南京北郊大气 VOCs 变化特征及来源解析

    Institute of Scientific and Technical Information of China (English)

    安俊琳; 朱彬; 王红磊; 杨辉

    2014-01-01

    Based on the data of volatile organic compounds (VOCs) collected continuously from 1st Mar, 2011 to 29th Feb, 2012 in the northern suburb of Nanjing, characteristics of their variability, differences of ratios of tracers and source apportionment by principal component analysis/ absolute principal component scores (PCA/ APCS) were analyzed. The results showed that the total VOCs mixing ratios were 43. 52 × 10 - 9 , which accounted for 45. 1% of alkanes, alkenes for 25. 3% , alkyne for 7. 3% , and aromatics for 22. 3% . There was an obviously seasonal variation of VOCs, with the maximum in summer and the minimum in winter. There was an obvious seasonal variation of VOCs component, with highest alkanes in winter, highest alkenes in summer, highest aromatic in spring, and highest alkyne in winter. By using the specific pollutant ratios ( hydrocarbons/ acetylene and toluene/ benzene) method, it indicated that the observation site was greatly affected by the surrounding industrial areas. Source analysis of VOCs by PCA/ APCS mode showed that the sources consisted of industrial production sources, automobile emission sources, combustion sources, industrial production volatilization sources, solvent use sources and biogenic emission sources. In addition, there were seasonal variations. Overall, the sources related to industrial production activities represented 45% - 63% of VOCs, and they were followed by automobile emission sources, which represented 34% -50% .%利用2011-03-01~2012-02-29南京北郊大气 VOCs 观测资料,对大气 VOCs 浓度变化特征和特征物比值差异展开研究,并应用 PCA/ APCS 受体模型对不同季节 VOCs 来源进行了解析.结果表明,南京大气总 VOCs 体积混合比为43.52×10-9,其中烷烃占45.1%、烯烃占25.3%、炔烃占7.3%和芳香烃占22.3%.总 VOCs 体积混合比呈现夏季高,冬季低的季节变化. VOCs 组分中烷烃在冬季最高,烯烃夏季最高,芳香烃春季最高,炔烃冬季最高.特征物比值(VOCs

  2. Investigations of the ratios of stable carbon isotopes in atmospheric relevant VOC using simulation and field experiments; Untersuchungen der Verhaeltnisse stabiler Kohlenstoffisotope in atmosphaerisch relevanten VOC in Simulations- und Feldexperimenten

    Energy Technology Data Exchange (ETDEWEB)

    Spahn, Holger

    2010-07-01

    Volatile organic compounds (VOC) play an important role in the regional and global atmospheric chemistry. The author of the contribution under consideration reports on the analysis of the ratios of stable carbon isotopes ({delta}({sup 13}C) analysis) in atmospheric VOCs. At first, the state of the art of this analytical technique is described. For the first time {delta}({sup 13}C) values of different monoterpenes have been determined in the investigation of vegetable emissions at a plant chamber. By means of the oxidation of {beta}-pinene by ozone in an aerosol chamber, the kinetic isotope effect of this reaction was determined. In southern Germany, air samples for the {delta}({sup 13}C) analysis were collected using a zeppelin. This enables a height-resolved measurement of {delta}({sup 13}C) values. Based on these measurements, the average photochemical age for methanol, toluene and p-xylene at different heights was calculated.

  3. Adolescent Toluene Inhalation in Rats Affects White Matter Maturation with the Potential for Recovery Following Abstinence

    Science.gov (United States)

    Egan, Gary; Kolbe, Scott; Gavrilescu, Maria; Wright, David; Lubman, Dan Ian; Lawrence, Andrew John

    2012-01-01

    Inhalant misuse is common during adolescence, with ongoing chronic misuse associated with neurobiological and cognitive abnormalities. While human imaging studies consistently report white matter abnormalities among long-term inhalant users, longitudinal studies have been lacking with limited data available regarding the progressive nature of such abnormalities, including the potential for recovery following periods of sustained abstinence. We exposed adolescent male Wistar rats (postnatal day 27) to chronic intermittent inhaled toluene (3,000 ppm) for 1 hour/day, 3 times/week for 8 weeks to model abuse patterns observed in adolescent and young adult human users. This dosing regimen resulted in a significant retardation in weight gain during the exposure period (ptoluene exposure during adolescence and early adulthood resulted in white matter abnormalities, including a decrease in axial (pToluene-induced effects on both body weight and white matter parameters recovered following abstinence. Behaviourally, we observed a progressive decrease in rearing activity following toluene exposure but no difference in motor function, suggesting cognitive function may be more sensitive to the effects of toluene. Furthermore, deficits in rearing were present by 4 weeks suggesting that toluene may affect behaviour prior to detectable white matter abnormalities. Consequently, exposure to inhalants that contain toluene during adolescence and early adulthood appear to differentially affect white matter maturation and behavioural outcomes, although recovery can occur following abstinence. PMID:23028622

  4. Extraction of toluene, o-xylene from heptane and benzyl alcohol from toluene with aqueous cyclodextrins

    NARCIS (Netherlands)

    Meindersma, G.W.; Schoonhoven, van T.; Kuzmanovic, B.; Haan, de A.B.

    2006-01-01

    The separation of aromatic compounds (toluene and o-xylene) from heptane and of benzyl alcohol from toluene with aqueous solutions of cyclodextrins has been experimentally investigated, because cyclodextrins and its derivatives can selectively incorporate several organic compounds, whereas the separ

  5. VOC and HAP recovery using ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Michael R. Milota : Kaichang Li

    2007-05-29

    During the manufacture of wood composites, paper, and to a lesser extent, lumber, large amounts of volatile organic compounds (VOCs) such as terpenes, formaldehyde, and methanol are emitted to air. Some of these compounds are hazardous air pollutants (HAPs). The air pollutants produced in the forest products industry are difficult to manage because the concentrations are very low. Presently, regenerative thermal oxidizers (RTOs and RCOs) are commonly used for the destruction of VOCs and HAPs. RTOs consume large amounts of natural gas to heat air and moisture. The combustion of natural gas generates increased CO2 and NOx, which have negative implications for global warming and air quality. The aforementioned problems are addressed by an absorption system containing a room-temperature ionic liquid (RTIL) as an absorbent. RTILs are salts, but are in liquid states at room temperature. RTILs, an emerging technology, are receiving much attention as replacements for organic solvents in industrial processes with significant cost and environmental benefits. Some of these processes include organic synthesis, extraction, and metal deposition. RTILs would be excellent absorbents for exhausts from wood products facilities because of their unique properties: no measurable vapor pressure, high solubility of wide range of organic compounds, thermal stability to 200°C (almost 400°F), and immisciblity with water. Room temperature ionic liquids were tested as possible absorbents. Four were imidizolium-based and were eight phosphonium-based. The imidizolium-based ionic liquids proved to be unstable at the conditions tested and in the presence of water. The phosphonium-based ionic liquids were stable. Most were good absorbents; however, cleaning the contaminates from the ionic liquids was problematic. This was overcome with a higher temperature (120°C) than originally proposed and a very low pressure (1 kPa. Absorption trials were conducted with tetradecy

  6. Membrane inlet proton transfer reaction mass spectrometry (MI-PTRMS) for direct measurements of VOCs in water

    Science.gov (United States)

    Boscaini, Elena; Alexander, Michael L.; Prazeller, Peter; Märk, Tilmann D.

    2004-12-01

    The use of a membrane inlet proton transfer reaction mass spectrometry (MI-PTRMS) system was investigated for the quantitative analysis of VOCs directly from water. Compounds playing an important role in environmental, biological and health issues such as methanol, acetonitrile, acetone, dimethylsulfide (DMS), isoprene, benzene, and toluene have been analyzed both in fresh and salty water. The system shows very good sensitivity, reproducibility, and a linear response of up to five orders of magnitude. The detection limit for DMS is about 100 ppt and for methanol is about 10 ppb both in fresh and salty water. The response time of the various compounds across the membrane is on the order of a few minutes. This fast response and the fact that the PTRMS can perform absolute measurements without the necessity of calibration make the system suitable for on-line and -site measurements of VOCs directly from water.

  7. Catalytic combustion of toluene on Pd/CeO2-TiO2 catalysts.

    Science.gov (United States)

    Chen, Yu-Wen; Lee, Der-Shing

    2013-03-01

    Pd/TiO2 and Pd/CeO2 were reported to be very active to destruct toluene. Combination of TiO2 and CeO2 is an interesting candidate to achieve a catalyst with higher activity. In this study, a series of Pd/CeO2-TiO2 catalysts with various Pd loadings were prepared. CeO2-TiO2 was prepared by impregnation of aqueous solution of cerium nitrate into TiO2 support. It was then calcined at 400 degrees C. Pd was loaded by incipient-wetness impregnation method. The Pd loadings in all samples were fixed at 0.5 wt.%. The catalysts were characterized by powder X-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy, temperature-programmed reduction of hydrogen, and X-ray photoelectron spectroscopy. The catalysts were tested for total oxidation of toluene. The feed concentration of toluene was 8.564 g/m3 (2085 ppm), with GHSV = 10,000 h(-1). Pd particle sizes were 3-5 nm and well-dispersed on the support. CeO2 on TiO2 was easier to reduce than the bulk CeO2, therefore it could enhance the activity of VOC destruction. Pd/CeO2-TiO2 was more active than Pd/CeO2 and Pd/TiO2. Pd/CeO2-TiO2 with Ce/Ti ratio of 2/8 was very active for toluene destruction, due to its lower oxygen reduction temperature of ceria and higher concentration of Pd(0).

  8. POCP for individual VOC under European conditions

    Energy Technology Data Exchange (ETDEWEB)

    Altenstedt, J.; Pleijel, K.

    1998-09-01

    Ground level ozone has been recognised as one of the most important environmental threats on the regional scale in Europe. Ozone is today considered to be harmful to human health already at the relatively low concentrations present in southern Scandinavia. The fact that ozone has the potential to damage vegetation at these concentrations is already well known. Ozone also gives rise to degradation of materials and is one of the gases which adds to the greenhouse effect. Ground level ozone is formed from nitrogen oxides (NO{sub x}) and volatile organic compounds (VOC) in the presence of sunlight. The only way to reduce ozone is therefore to reduce the emissions of the precursors. Ranking individual VOC by their ozone formation potential can make emission reductions more environmentally efficient and save time and money. POCP values give a ranking of the ozone formation ability of an individual VOC relative to other VOC. A critical analysis of the POCP concept has been performed which shows that the background emissions of NO{sub x} and VOC affect the POCP values to a large extent. Based on the critical analysis, five scenarios with different background emissions of NO{sub x} and VOC were selected for calculation of POCP values. These scenarios were chosen because they reflect the variation in POCP values which arise in different environments within Europe. The range thus indicates POCP values which are intended to be applicable within Europe. POCP values for 83 different VOC are presented in the form of ranges in this report. 42 refs, 13 figs, 3 tabs

  9. Effect of preparation method on the catalytic activity of Au/CeO_2 for VOCs oxidation

    Institute of Scientific and Technical Information of China (English)

    李锦卫; 黎维彬

    2010-01-01

    The Au/CeO2 catalysts were synthesized by co-precipitation (CP), deposition-precipitation (DP) and metallic colloids deposition (MCD) method, and tested for oxidation of volatile organic compounds (VOCs). It was revealed that the Au/CeO2 catalyst prepared by DP method was the most efficient catalyst towards the total oxidation of toluene. The Au/CeO2 catalysts had obviously high catalytic activity, and the best results was obtained on 3 wt.% Au/CeO2 catalyst prepared by DP method. These catalysts were chara...

  10. Characterizations of volatile organic compounds (VOCs) from vehicular emissions at roadside environment: The first comprehensive study in Northwestern China

    Science.gov (United States)

    Li, Bowei; Ho, Steven Sai Hang; Xue, Yonggang; Huang, Yu; Wang, Liqin; Cheng, Yan; Dai, Wenting; Zhong, Haobin; Cao, Junji; Lee, Shuncheng

    2017-07-01

    Vehicular emission (VE) is one of the important anthropogenic sources for ground-level volatile organic compounds (VOCs) in both urban and suburban areas. A first comprehensive campaign was conducted at an urban roadside in Xi'an, China in summer, 2016. A total of 57 VOCs, as known as critical surface ozone (O3) precursors, and other trace gases were measured simultaneously during the sampling period. Iso-pentane, a tracer of gasoline evaporation, was the most abundant VOC in the roadside samples, followed by isobutane and benzene, attributed to the largest composition (∼70%) of gasoline-fueled vehicles on the road. The molar ratio of toluene/benzene (T/B) in our study (0.36) is far lower than the range reported in other cities, indicating the stronger contributions from diesel emissions. The results of source apportionment achieved with positive matrix factorization (PMF) receptor model were highly consistent with the vehicles compositions, strongly evidenced that the precise characterization of the VE sources from those marker species. The degrees of individual compound contributed to O3 production were weighed by ozone formation potential (OFP). Propylene (20%), 1-butene (11%) and iso-pentane(10%) were the top three contributors at the roadside. The information of this study complements the VOCs database regarding to the VE sources in Northwestern China.

  11. 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.

  12. VOC Composition of Air Masses Transported from Asia to the U.S. West Coast

    Science.gov (United States)

    de Gouw, J.; Warneke, C.; Kuster, B.; Parrish, D.; Holloway, J.; Huebler, G.; Fehsenfeld, F.

    2002-12-01

    Airborne measurements of volatile organic compounds (VOCs) were performed using a proton-transfer-reaction mass spectrometer (PTR-MS) operated onboard a NOAA WP-3 aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in 2002. Enhancements of acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN) and in some cases benzene were observed in air masses that were impacted by outflow from Asia. The enhancement ratios with respect to carbon monoxide are compared to emission factors for fossil fuel combustion and biomass burning, which gives some insight into the sources responsible for the pollution. The observed mixing ratios for acetone, methanol and in particular acetonitrile were generally reduced in the marine boundary layer, suggesting the presence of an ocean uptake sink. The ocean uptake of acetonitrile was found to be particularly efficient in a zone with upwelling water off of the U.S. west coast. Reduced mixing ratios of acetone and methanol were observed in a stratospheric intrusion. This observation gives some information about the lifetime of these VOCs in the stratosphere. Enhanced concentrations of aromatic hydrocarbons were observed in air masses that were impacted by urban sources in California. The ratio between the concentrations of benzene, toluene and higher aromatics indicated the degree of photochemical oxidation. PTR-MS only gives information about the mass of the ions produced by proton-transfer reactions between H3O+ and VOCs in the instrument. The identification of VOCs was confirmed by coupling a gas-chromatographic (GC) column to the instrument and post-flight GC-PTR-MS analyses of canister samples collected during the flights.

  13. Effects of adsorptive properties of biofilter packing materials on toluene removal.

    Science.gov (United States)

    Oh, Dong Ik; Song, Jihyeon; Hwang, Sun Jin; Kim, Jae Young

    2009-10-15

    Various adsorptive materials, including granular activated carbon (GAC) and ground tire rubber (GTR), were mixed with compost in biofilters used for treating gaseous toluene, and the effects of the mixtures on the stability of biofilter performance were investigated. A transient loading test demonstrated that a sudden increase in inlet toluene loading was effectively attenuated in the compost/GAC biofilter, which was the most significant advantage of adding adsorptive materials to the biofilter packing media. Under steady conditions with inlet toluene loading rates of 18.8 and 37.5 g/m(3)/h, both the compost and the compost/GAC biofilters achieved overall toluene removal efficiencies greater than 99%. In the compost/GAC mixture, however, biodegradation activity declined as the GAC mass fraction increased. Because of the low water-holding capacity of GTR, the compost/ground tire mixture did not show a significant improvement in toluene removal efficiency throughout the entire operational period. Furthermore, nitrogen limitations affected system performance in all the biofilters, but an external nitrogen supply resulted in the recovery of the toluene removal efficiency only in the compost biofilter during the test periods. Consequently, the introduction of excessive adsorptive materials was unfavorable for long-term performance, suggesting that the mass ratio of the adsorptive materials in such mixtures should be carefully selected to achieve high and steady biofilter performance.

  14. Screening-level human health risk assessment of toluene and dibutyl phthalate in nail lacquers.

    Science.gov (United States)

    Kopelovich, Luda; Perez, Angela L; Jacobs, Neva; Mendelsohn, Emma; Keenan, James J

    2015-07-01

    Toluene and dibutyl phthalate (DBP) are found in many consumer products, including cosmetics, synthetic fragrances, and nail polish. In 2012, the California Environmental Protection Agency evaluated 25 nail products and found that 83% of the products that claimed to be toluene-free contained toluene at concentrations ranging up to 190,000 ppm, and 14% of the products that claimed to be DBP-free contained DBP at concentrations ranging up to 88,000 ppm. We conducted a preliminary, screening-level analysis of the potential toluene and DBP-related health risks to consumers and professionals based on the medium and maximum concentrations of toluene and DBP presented in the 2012 report and evaluated dermal and inhalation exposure to a salon patron, nail technician, and home user. We concluded that the maximum toluene concentration for the technician and home user scenarios exceeded the California MADL, but the estimated air concentrations did not exceed the Federal or Cal OSHA PEL. The MADL for DBP was exceeded for all user scenarios at both the median and maximum concentrations. Using these highly conservative assumptions, exposures above regulatory limits could possibly occur during routine use of nail products; further research is needed in order to evaluate potential human health risks. Published by Elsevier Ltd.

  15. Age-dependent time courses of recovery for motor functions following acute toluene intoxication in rats.

    Science.gov (United States)

    Samuel-Herter, Susan R; Slaght, Shelby L; McKay, Bruce E

    2014-05-01

    Toluene is a psychoactive chemical found in many household products including adhesives and thinners. Inhalation of these vapors can cause euphoria and impairments in motor control and neurological functioning. Misuse and abuse of toluene is most common in children, which may in part be due to an age-dependent neurobehavioral sensitivity to toluene. Here we assessed the effects of acute binge-like toluene inhalations (15 or 30 min; ∼5,000 ppm) on tasks that examine locomotion, exploration, balance, gait, and neurological functioning for adolescent (1 month), young adult (2-3 months), adult (5-6 months), and older adult (10-12 months) rats. Both motor and neurological functions were impaired following acute toluene inhalation at all ages. However, only the duration to recover from deficits in motor functions differed among age groups, with adolescent and young adult rats requiring notably longer recovery times than older rats. Our results are suggestive of an age-dependent vulnerability to the intoxicating effects of toluene. © 2013 Wiley Periodicals, Inc.

  16. Plant volatile organic compounds (VOCs) in ozone (O3) polluted atmospheres: the ecological effects.

    Science.gov (United States)

    Pinto, Delia M; Blande, James D; Souza, Silvia R; Nerg, Anne-Marja; Holopainen, Jarmo K

    2010-01-01

    Tropospheric ozone (O3) is an important secondary air pollutant formed as a result of photochemical reactions between primary pollutants, such as nitrogen oxides (NOx), and volatile organic compounds (VOCs). O3 concentrations in the lower atmosphere (troposphere) are predicted to continue increasing as a result of anthropogenic activity, which will impact strongly on wild and cultivated plants. O3 affects photosynthesis and induces the development of visible foliar injuries, which are the result of genetically controlled programmed cell death. It also activates many plant defense responses, including the emission of phytogenic VOCs. Plant emitted VOCs play a role in many eco-physiological functions. Besides protecting the plant from abiotic stresses (high temperatures and oxidative stress) and biotic stressors (competing plants, micro- and macroorganisms), they drive multitrophic interactions between plants, herbivores and their natural enemies e.g., predators and parasitoids as well as interactions between plants (plant-to-plant communication). In addition, VOCs have an important role in atmospheric chemistry. They are O3 precursors, but at the same time are readily oxidized by O3, thus resulting in a series of new compounds that include secondary organic aerosols (SOAs). Here, we review the effects of O3 on plants and their VOC emissions. We also review the state of current knowledge on the effects of ozone on ecological interactions based on VOC signaling, and propose further research directions.

  17. Locating industrial VOC sources with aircraft observations

    Energy Technology Data Exchange (ETDEWEB)

    Toscano, P., E-mail: p.toscano@ibimet.cnr.it [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Gioli, B. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Dugheri, S. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Salvini, A. [Department of Organic Chemistry, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Florence (Italy); Matese, A. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Bonacchi, A. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Zaldei, A. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Cupelli, V. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Miglietta, F. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Fondazione Edmund Mach, Via Mach 1, San Michele all' Adige, Trento (Italy)

    2011-05-15

    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{sub 2}. > Concentrations obtained were lower than the limit values or below the detection limit. > Scan mode highlighted presence of {gamma}-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.

  18. Excited state of protonated benzene and toluene

    Energy Technology Data Exchange (ETDEWEB)

    Esteves-López, Natalia; Dedonder-Lardeux, Claude; Jouvet, Christophe, E-mail: Christophe.jouvet@univ-amu.fr [Aix-Marseille Université, CNRS, UMR-7345, Physique des Interactions Ioniques et Moléculaires (PIIM), Marseille (France)

    2015-08-21

    We present photo-fragmentation electronic spectra of the simplest protonated aromatic molecules, protonated benzene and toluene, recorded under medium resolution conditions and compared with the photo-fragmentation spectrum of protonated pyridine. Despite the resolution and cold temperature achieved in the experiment, the electronic spectra of protonated benzene and toluene are structure-less, thus intrinsically broadened. This is in agreement with the large geometrical changes and the fast dynamic toward internal conversion predicted by ab initio calculations for protonated benzene [Rode et al., J. Phys. Chem. A 113, 5865–5873 (2009)].

  19. 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.

  20. VOC methods and levels in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Bomboi, M.T. [Area de Contaminacion Atmosferica, Instituto de Salud Carlos III, Majadahonda (Spain)

    2004-07-01

    Ozone precursors began to be studied in the eighties in Spain, in order to know their levels and composition in areas, which had high concentrations of other atmospheric polluting agents. At the end of the eighties, VOC were incorporated into the air quality networks in urban areas in order to anticipate at the derived amendments of the entrance into force on the Directive 92/72/CEE of 1992 on air pollution by ozone. At the same time, field campaigns for VOC toxics were started in specific industrial areas and the zones with high traffic. More recently, the air quality networks have been orientated to non-urban areas, to cover the knowledge of VOC in semi-urban and rural areas. On the other hand, the role of the biogenic emissions and the role that their chemical and photochemical products play in atmospheric chemistry was becoming important in the nineties. Therefore some research projects, e.g. 'Biogenic Emissions in the Mediterranean Area (BEMA)', were developed in order to understand the vegetation emissions in the Mediterranean area in relation to anthropogenic compounds and to get information on their participation in tropospheric ozone formation. VOC have been sampled at European Monitoring and Evaluation Programme (EMEP) sites since 1999, based on recommendations from the EMEP Workshop on Measurements of Hydrocarbons/VOC in Lindau 1989. Collection of light hydrocarbons started in 1999, whereas measurements of carbonyls have just started in 2003. In this work, the most important sampling and analysis techniques to determine ozone precursors and to control VOC are shown, as well as the main results obtained in projects, networks and measurement campaigns performed with these methods.

  1. Silica deactivation of bead VOC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Libanati, C.; Pereira, C.J. [Research Division, W. R. Grace and Co., Columbia, MD (United States); Ullenius, D.A. [Grace TEC Systems, De Pere, WI (United States)

    1998-01-15

    Catalytic oxidation is a key technology for controlling the emissions of Volatile Organic Compounds (VOCs) from industrial plants. The present paper examines the deactivation by silica of bead VOC catalysts in a flexographic printing application. Post mortem analyses of field-aged catalysts suggest that organosilicon compounds contained in the printing ink diffuse into the catalyst and deposit as silica particles in the micropores. Laboratory activity evaluation of aged catalysts suggests that silica deposition is non-selective and that silica masks the noble metal active site

  2. PREPARATION OF CUO/γ-Al2O3 CATALYSTS FOR CATALYTIC COMBUSTION VOCS VIA PLASMA

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    CuO/γ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuO/γ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuO/γ-Al2O3 catalyst prepared via plasma was much higher than that of the CuO/γ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.

  3. An SOA model for toluene oxidation in the presence of inorganic aerosols.

    Science.gov (United States)

    Cao, Gang; Jang, Myoseon

    2010-01-15

    A predictive model for secondary organic aerosol (SOA) formation including both partitioning and heterogeneous reactions is explored for the SOA produced from the oxidation of toluene in the presence of inorganic seed aerosols. The predictive SOA model comprises the explicit gas-phase chemistry of toluene, gas-particle partitioning, and heterogeneous chemistry. The resulting products from the explicit gas phase chemistry are lumped into several classes of chemical species based on their vapor pressure and reactivity for heterogeneous reactions. Both the gas-particle partitioning coefficient and the heterogeneous reaction rate constant of each lumped gas-phase product are theoretically determined using group contribution and molecular structure-reactivity. In the SOA model, the predictive SOA mass is decoupled into partitioning (OM(P)) and heterogeneous aerosol production (OM(H)). OM(P) is estimated from the SOA partitioning model developed by Schell et al. (J. Geophys. Res. 2001, 106, 28275-28293 ) that has been used in a regional air quality model (CMAQ 4.7). OM(H) is predicted from the heterogeneous SOA model developed by Jang et al. (Environ. Sci. Technol. 2006, 40, 3013-3022 ). The SOA model is evaluated using a number of the experimental SOA data that are generated in a 2 m(3) indoor Teflon film chamber under various experimental conditions (e.g., humidity, inorganic seed compositions, NO(x) concentrations). The SOA model reasonably predicts not only the gas-phase chemistry, such as the ozone formation, the conversion of NO to NO(2), and the toluene decay, but also the SOA production. The model predicted that the OM(H) fraction of the total toluene SOA mass increases as NO(x) concentrations decrease: 0.73-0.83 at low NO(x) levels and 0.17-0.47 at middle and high NO(x) levels for SOA experiments with high initial toluene concentrations. Our study also finds a significant increase in the OM(H) mass fraction in the SOA generated with low initial toluene

  4. Human response to varying concentrations of toluene

    DEFF Research Database (Denmark)

    Bælum, Jesper; Lundqvist, G R; Mølhave, Lars

    1990-01-01

    less than 0.1) towards irritation in the throat, headache and dizziness. In the four performance tests there was a tendency towards a lower score in a vigilance test while no effect of toluene exposure was seen in a peg board test, a five choice serial reaction test, or a colour test, indicating only...

  5. A High Performance Biofilter for VOC Emission Control.

    Science.gov (United States)

    Wu, G; Conti, B; Leroux, A; Brzezinski, R; Viel, G; Heitz, M

    1999-02-01

    Biofiltration is a cleaning technique for waste air contaminated with some organic compounds. The advantages of the conventional biofilter over other biological systems are a high-superficial area best suited for the treatment of some compounds with poor water solubility, ease of operation, and low operating costs. It has crucial disadvantages, however; for example, it is not suitable to treat waste gases with high VOC concentrations and it has poor control of reaction conditions. To improve on these problems and to build a high-performance biofilter, three structured peat media and two trickling systems have been introduced in this study. The influences of media size and composition have been investigated experimentally. Peat bead blended with 30% (w/w) certain mineral material with a good binding capacity has advantages over other packing materials, for example, suitable size to prevent blockage due to microbial growth, strong buffering capacity to neutralize acidic substances in the system, and a pH range of 7.0-7.2 suitable for the growth of bacteria. Dropwise trickling system offers an effective measure to easily control the moisture content of the bed and the reaction conditions (pH, nutrient) and to partially remove excess biomass produced during the metabolic processes of microorganisms. The influence of nutrient supplementation has also been investigated in this study, which has revealed that the biological system was in a condition of nutrient limitation instead of carbon limitation. The biofilters built in our laboratory were used to treat waste gas contaminated with toluene in a concentration range of 1 to 3.2 g/m(3) and at the specific gas flow rate of 24 to120 m(3)/m(2).hr. Under the conditions employed, a high elimination capacity (135 g/m(3).hr) was obtained in the biofilter packed with peat beads (blended with 30% of the mineral material), and no blockage problem was observed in an experimental period of 2-3 months.

  6. Simultaneous removal of ethyl acetate, benzene and toluene with gliding arc gas discharge

    Institute of Scientific and Technical Information of China (English)

    Zheng BO; Jian-hua YAN; Xiao-dong LI; Yong CHI; Ke-fa CEN

    2008-01-01

    The simultaneous removal of ethyl acetate, benzene and toluene with relatively low or high initial concentration is studied using a laboratory scale gliding arc gas discharge (GA) reactor. Good decomposition efficiencies are obtained which proves that the GA is effective for the treatment of volatile organic compounds (VOCs) with either low or high concentration. A theoretical decomposition mechanism is proposed based on detection of the species in the plasma region and analysis of the decomposition by-products. This preliminary investigation reveals that the GA has potential to be applied to the treatment of exhaust air during color printing and coating works, by either direct removal or combination with activated carbon adsorption/desorption process.

  7. GEIGER BRICKEL BENEFITS FROM LOW -VOC COATINGS

    Science.gov (United States)

    Midwest Research Institute, under a cooperative agreement with the U.S. Environmental Protection Agency (EPA), conducted a study to identify wood furniture manufacturing facilities that had converted to low-volatile organic compound (VOC)/hazardous air pollutant (HAP) wood furnit...

  8. High-molecular products analysis of VOC destruction in atmospheric pressure discharge

    Science.gov (United States)

    Grossmannova, Hana; Ciganek, Miroslav; Krcma, Frantisek

    2007-04-01

    We investigate the issue of applicability of the solid phase microextraction (SPME) in the analysis of volatile organic compounds (VOCs) destruction products in the gliding arc discharge. Our research is focused on the measurements with the simple one stage gliding arc reactor, applied voltage was varied in the range of 3.5-4 kV. As a carrier gas, the dry air and its mixtures with nitrogen and oxygen, enriched by toluene, with flow rate of 1000-3500 ml/min was used. Total decomposition of toluene of 97 % was achieved at the oxygen content in carrier gas of 60 %. For measurements with air as a carrier gas, the highest efficiency was 95 %. We also tested the SPME technique suitability for the quantitative analysis of exhausts gases and if this technique can be used efficiently in the field to extract byproducts. Carbowax/divinylbenzene and Carboxen/polydimethylsiloxane/divinylbenzene fibres were chosen for sampling. Tens of various high-molecular substances were observed, especially a large number of oxygenous compounds and further several nitrogenous and CxHy compounds. The concentrations of various generated compounds strongly depend on the oxygen content in gas mixture composition. The results showed that the fiber coated by Carbowax/divinylbenzene can extract more products independently on the used VOC compound. The Carboxen/polydimethylsiloxane/divinylbenzene fiber is useful for the analysis of oxygenous compounds and its use will be recommended especially when the destruction is done in the oxygen rich atmosphere. With the higher ratio of oxygen in the carrier gas a distinctive decline of CxHy compounds amount have been observed. We also tried to describe the significant production of some compounds like benzyl alcohol, benzeneacetaldehyde, even in oxygen content is proximate 0 %. Experimental data demonstrated that it is necessary to use several SPME fibres for full-scale high-molecular products analysis.

  9. Complications of chronic glue (toluene) abuse in adolescents.

    Science.gov (United States)

    Devathasan, G; Low, D; Teoh, P C; Wan, S H; Wong, P K

    1984-02-01

    Recently there has been an alarming increase in the number of schoolchildren sniffing glue (toluene). The medical complications seen in 18 boys, aged 14 to 18 years, include physical and mental dependence, pulmonary hypertension with cor pulmonale, restrictive lung defect, encephalopathy, peripheral neuropathy and high frequency, continuous discharges ( neuromyotonia ) on electromyogram. Glue sniffing took place in small groups and abusers sniffed directly from cans containing glue. Lower socio-economic status, overcrowding, lack of attention by working parents, school failure and easy availability of the glue were commonly cited associated factors.

  10. Occupational Toluene Exposure Induces Cytochrome P450 2E1 mRNA Expression in Peripheral Lymphocytes

    OpenAIRE

    Mendoza-Cantú, Ania; Castorena-Torres, Fabiola; León,Mario Bermúdez de; Cisneros, Bulmaro; López-Carrillo, Lizbeth; Rojas-García, Aurora E.; Aguilar-Salinas, Alberto; Manno, Maurizio; Albores, Arnulfo

    2005-01-01

    Print workers are exposed to organic solvents, of which the systemic toxicant toluene is a main component. Toluene induces expression of cytochrome P450 2E1 (CYP2E1), an enzyme involved in its own metabolism and that of other protoxicants, including some procarcinogens. Therefore, we investigated the association between toluene exposure and the CYP2E1 response, as assessed by mRNA content in peripheral lymphocytes or the 6-hydroxychlorzoxazone (6OH-CHZ)/chlorzoxazone (CHZ) quotient (known as ...

  11. A membrane bioreactor for the simultaneous treatment of acetone, toluene, limonene and hexane at trace level concentrations.

    Science.gov (United States)

    Lebrero, R; Volckaert, D; Pérez, R; Muñoz, R; Van Langenhove, H

    2013-05-01

    The performance of a flat-membrane biofilm reactor (MBR) for the removal of acetone, toluene, limonene and hexane at concentrations ranging from 1.3 to 3.2 mg m(-3) was investigated at different gas residence times (GRT): 60, 30, 15 and 7 s. A preliminary abiotic test was conducted to assess the mass transport of the selected volatile organic compounds (VOCs) through the membrane. A reduced transport of limonene and hexane was observed with water present over the dense side of the membrane. The presence of a biofilm attached on the dense side of the membrane following bioreactor inoculation significantly increased VOC transport. High acetone and toluene removals (>93%) were recorded in the MBR regardless of the GRT. To remediate the low hexane removal performance (RE hexane-degrading consortium embedded in silicon oil was performed. Although hexane removal did not exceed 27%, this re-inoculation increased limonene removals up to 90% at a GRT of 7 s. The absence of inhibition of hexane biodegradation by substrate competition confirmed that hexane removal in the MBR was indeed limited by the mass transfer through the membrane. Despite the low carbon source spectrum and load, the microbiological analysis of the communities present in the MBR showed high species richness (Shannon-Wiener indices of 3.2-3.5) and a high pair-wise similarity (84-97%) between the suspended and the attached biomass.

  12. Micronuclei in Bone Marrow and Liver in relation to Hepatic Metabolism and Antioxidant Response due to Coexposure to Chloroform, Dichloromethane, and Toluene in the Rat Model

    Directory of Open Access Journals (Sweden)

    Javier Belmont-Díaz

    2014-01-01

    Full Text Available Genotoxicity in cells may occur in different ways, direct interaction, production of electrophilic metabolites, and secondary genotoxicity via oxidative stress. Chloroform, dichloromethane, and toluene are primarily metabolized in liver by CYP2E1, producing reactive electrophilic metabolites, and may also produce oxidative stress via the uncoupled CYP2E1 catalytic cycle. Additionally, GSTT1 also participates in dichloromethane activation. Despite the oxidative metabolism of these compounds and the production of oxidative adducts, their genotoxicity in the bone marrow micronucleus test is unclear. The objective of this work was to analyze whether the oxidative metabolism induced by the coexposure to these compounds would account for increased micronucleus frequency. We used an approach including the analysis of phase I, phase II, and antioxidant enzymes, oxidative stress biomarkers, and micronuclei in bone marrow (MNPCE and hepatocytes (MNHEP. Rats were administered different doses of an artificial mixture of CLF/DCM/TOL, under two regimes. After one administration MNPCE frequency increased in correlation with induced GSTT1 activity and no oxidative stress occurred. Conversely, after three-day treatments oxidative stress was observed, without genotoxicity. The effects observed indicate that MNPCE by the coexposure to these VOCs could be increased via inducing the activity of metabolism enzymes.

  13. The Abused Inhalant Toluene Differentially Modulates Excitatory and Inhibitory Synaptic Transmission in Deep-Layer Neurons of the Medial Prefrontal Cortex

    Science.gov (United States)

    Beckley, Jacob T; Woodward, John J

    2011-01-01

    Volatile organic solvents such as toluene are voluntarily inhaled for their intoxicating effects. Solvent use is especially prevalent among adolescents, and is associated with deficits in a wide range of cognitive tasks including attention, behavioral control, and risk assessment. Despite these findings, little is known about the effects of toluene on brain areas mediating these behaviors. In this study, whole-cell patch-clamp recordings were used to determine the effect toluene on neurons within the medial PFC, a region critically involved in cognitive function. Toluene had no effect on measures of intrinsic excitability, but enhanced stimulus-evoked γ-amino butyric acid A-mediated inhibitory postsynaptic currents (IPSCs). In the presence of tetrodotoxin (TTX) to block action potentials, toluene increased the frequency and amplitude of miniature IPSCs. In contrast, toluene induced a delayed but persistent decrease in evoked or spontaneous AMPA-mediated excitatory postsynaptic currents (EPSCs). This effect was prevented by an intracellular calcium chelator or by the ryanodine receptor and SERCA inhibitors, dantrolene or thapsigargin, respectively, suggesting that toluene may mobilize intracellular calcium pools. The toluene-induced reduction in AMPA EPSCs was also prevented by a cannabinoid receptor (CB1R) antagonist, and was occluded by the CB1 agonist WIN 55,212-2 that itself induced a profound decrease in AMPA-mediated EPSCs. Toluene had no effect on the frequency or amplitude of miniature EPSCs recorded in the presence of TTX. Finally, toluene dose-dependently inhibited N-methyl--aspartate (NMDA)-mediated EPSCs and the magnitude and reversibility of this effect was CB1R sensitive indicating both direct and indirect actions of toluene on NMDA-mediated responses. Together, these results suggest that the effect of toluene on cognitive behaviors may result from its action on inhibitory and excitatory synaptic transmission of PFC neurons. PMID:21430649

  14. 用修正的Polanyi-Dubinin方程描述有机蒸气-水蒸气在活性炭上的吸附平衡%MODIFIED POLANYI-DUBININ EQUATION TO ORRELATE ADSORPTION EQUILIBRIUM OF VOC-WATER VAPOR MIXTURES ON ACTIVATED CARBON

    Institute of Scientific and Technical Information of China (English)

    高华生; 汪大翚; 叶芸春; 谭天恩

    2001-01-01

    Long-column method was used to determine the adsorption isotherms of 4 VOCs (benzene, toluene, chloroform and acetone) in concentration range of 250~5000?mg*m-3 on a commercial activated-carbon under different humidity levels at 30?℃.A modified Polanyi-Dubinin equation was proposed to correlate the adsorption equilibrium of different VOC-water vapor systems. Among 3 methods of calculating the Relative Affinity Coefficient β used,the Molar Volume method and the Molecular Parachor method proved to be suitable for the calculation with better precision than the Electronic Polarization method. Calculation results were satisfactory for the benzene-, toluene-, and chloroform-water vapor/activated carbon systems, but poor for acetone possibly because of its strong polarity.The equation could be used to estimate the detaining effect of atmospheric humidity on the adsorption equilibrium of VOCs on activated carbon.

  15. [Toluene, Benzene and Acetone Adsorption by Activated Carbon Coated with PDMS].

    Science.gov (United States)

    Liu, Han-bing; Jiang, Xin; Wang, Xin; Yang, Bing; Xue, Nan-dong; Zhang, Shi-lei

    2016-04-15

    To improve the adsorption selectivity of volatile organic compounds ( VOCs) , activated carbon ( AC) was modified by polydimethylsiloxane (PDMS) and characterized by BET analysis and Boehm titration. Dynamic adsorption column experiments were conducted and Yoon-Neslon(Y-N) model was used to identify adsorption effect for toluene, beuzene and acetone on AC when relative humidity was 0%, 50% and 90%, respectively. The results showed that the BET area, micropore volume and surface functional groups decreased with the PDMS modification, and surface hydrophobicity of the modified AC was enhanced leading to a lower water adsorption capacity. The results of dynamic adsorption showed that the adsorption kinetics and capacity of Bare-AC decreased with the increase of relative humidity, and the adsorption capacities of PDMS coated AC were 1.86 times (toluene) and 1.92 times (benzene) higher than those of Bare-AC, while a significant improvement of adsorption capacity for acetone was not observed. These findings suggest that polarity of molecule can be an important influencing factor for adsorption on hydrophobic surface developed by PDMS.

  16. CHARACTERIZATION OF LOW-VOC LATEX PAINTS: VOLATILE ORGANIC COMPOUND CONTENT, VOC AND ALDEHYDE EMISSIONS, AND PAINT PERFORMANCE

    Science.gov (United States)

    The report gives results of laboratory tests to evaluate commercially available latex paints advertised as "low-odor," "low-VOC (volatile organic compound)," or "no-VOC." Measurements were performed to quantify the total content of VOCs in the paints...

  17. 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.

  18. Spatial and temporal trends of volatile organic compounds (VOC) in a rural area of northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Parra, M.A.; Gonzalez, L.; Elustondo, D.; Garrigo, J.; Bermejo, R.; Santamaria, J.M. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra, Irunlarrea s/n, 31080, Pamplona, Navarra (Spain)

    2006-10-15

    Ambient concentrations of volatile organic compounds (VOCs) were measured at 40 rural sampling points in Navarre (northern Spain). Air samples were collected by means of sorbent passive sampling and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD). A total of 140 VOCs were identified during the study, which was carried out between May to October 2004 for a total of a 10 biweekly sampling campaigns. Concentrations of benzene, toluene, ethylbenzene, m/p-xylenes, o-xylene (BTEX) and 1,3,5-trimethylbenzene were determined in order to investigate their temporal and spatial distributions. Geostatistical analysis pointed to traffic as the main emission source of these compounds. Supporting this idea, BTEX and nitrogen oxides concentrations were found to be highly significantly correlated (r=0.495, P=0.001), whereas a strong negative correlation between BTEX and ozone was also observed (r=-0.355, P=0.025). The concentrations for the BTEX group were similar to the values that have been previously reported for other rural areas. (author)

  19. TD-GC-MS Investigation of the VOCs Released from Blood Plasma of Dogs with Cancer

    Directory of Open Access Journals (Sweden)

    Seung-Woo Lee

    2013-01-01

    Full Text Available An analytical TD-GC-MS method was developed and used for the assessment of volatile organic compounds (VOCs released from the blood plasma of dogs with/without cancer. VOCs released from 40 samples of diseased blood and 10 control samples were compared in order to examine the difference between both sample groups that were showing qualitatively similar results independent from the disease’s presence. However, mild disturbances in the spectra of dogs with cancer in comparison with the control group were observed, and six peaks (tentatively identified by comparison with mass spectral library as hexanal, octanal, toluene, 2-butanone, 1-octen-3-ol and pyrrole revealed statistically significant differences between both sample groups, thereby suggesting that these compounds are potential biomarkers that can be used for cancer diagnosis based on the blood plasma TD-GC-MS analysis. Statistical comparison with the application of principal component analysis (PCA provided accurate discrimination between the cancer and control groups, thus demonstrating stronger biochemical perturbations in blood plasma when cancer is present.

  20. Cerium, manganese and cerium/manganese ceramic monolithic catalysts. Study of VOCs and PM removal

    Institute of Scientific and Technical Information of China (English)

    COLMAN-LERNER Esteban; PELUSO Miguel Andrs; SAMBETH Jorge; THOMAS Horacio

    2016-01-01

    Ceramic supported cerium, manganese and cerium-manganese catalysts were prepared by direct impregnation of aqueous precursor, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller method (BET), temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) acidity measurements and electrical conductivity. The catalytic activity was evaluated for volatile organic compounds (VOC) (ethanol, methyl ethyl ketone and toluene) oxidation. Additionally, catalysts were tested in particulate matter (PM) combustion. The characterization results indicated that Ce was in the form of Ce4+ and Ce3+, and Mn existed in the form of Mn4+and Mn3+on the surface of the Mn/AC sample and in the form of Mn4+ in the Ce/Mn/AC monolith. VOC oxidation results revealed that the Ce/Mn/AC sample showed an excellent performance compared with ceramic supported CeO2 (Ce/AC) and MnOx (Mn/AC) samples. The PM combustion was also higher on Ce/Mn/AC monoliths. The enhanced catalytic activity was mainly attributed to the Ce and Mn interaction which enhanced the acidity, conductiv-ity and the reducibility of the oxides.

  1. Effect of trichloroethylene (TCE) and toluene concentrations on TCE and toluene biodegradation and the population density of TCE and toluene degraders in soil.

    OpenAIRE

    Mu, D Y; Scow, K M

    1994-01-01

    Toluene is one of several cosubstrates able to support the cometabolism of trichloroethylene (TCE) by soil microbial communities. Indigenous microbial populations in soil degraded TCE in the presence, but not the absence, of toluene after a 60- to 80-h lag period. Initial populations of toluene and TCE degraders ranged from 0.2 x 10(3) to 4 x 10(3) cells per g of soil and increased by more than 4 orders of magnitude after the addition of 20 micrograms of toluene and 1 microgram of TCE per ml ...

  2. Occupational Toluene Exposure Induces Cytochrome P450 2E1 mRNA Expression in Peripheral Lymphocytes

    Science.gov (United States)

    Mendoza-Cantú, Ania; Castorena-Torres, Fabiola; de León, Mario Bermúdez; Cisneros, Bulmaro; López-Carrillo, Lizbeth; Rojas-García, Aurora E.; Aguilar-Salinas, Alberto; Manno, Maurizio; Albores, Arnulfo

    2006-01-01

    Print workers are exposed to organic solvents, of which the systemic toxicant toluene is a main component. Toluene induces expression of cytochrome P450 2E1 (CYP2E1), an enzyme involved in its own metabolism and that of other protoxicants, including some procarcinogens. Therefore, we investigated the association between toluene exposure and the CYP2E1 response, as assessed by mRNA content in peripheral lymphocytes or the 6-hydroxychlorzoxazone (6OH-CHZ)/chlorzoxazone (CHZ) quotient (known as CHZ metabolic ratio) in plasma, and the role of genotype (5′-flanking region RsaI/PstI polymorphic sites) in 97 male print workers. The geometric mean (GM) of toluene concentration in the air was 52.80 ppm (10–760 ppm); 54% of the study participants were exposed to toluene concentrations that exceeded the maximum permissible exposure level (MPEL). The GM of urinary hippuric acid at the end of a work shift (0.041 g/g creatinine) was elevated relative to that before the shift (0.027 g/g creatinine; p < 0.05). The GM of the CHZ metabolic ratio was 0.33 (0–9.3), with 40% of the subjects having ratios below the GM. However, the average CYP2E1 mRNA level in peripheral lymphocytes was 1.07 (0.30–3.08), and CYP2E1 mRNA levels within subjects correlated with the toluene exposure ratio (environmental toluene concentration:urinary hippuric acid concentration) (p = 0.014). Genotype did not alter the association between the toluene exposure ratio and mRNA content. In summary, with further validation, CYP2E1 mRNA content in peripheral lymphocytes could be a sensitive and noninvasive biomarker for the continuous monitoring of toluene effects in exposed persons. PMID:16581535

  3. Occupational toluene exposure induces cytochrome P450 2E1 mRNA expression in peripheral lymphocytes.

    Science.gov (United States)

    Mendoza-Cantú, Ania; Castorena-Torres, Fabiola; Bermúdez de León, Mario; Cisneros, Bulmaro; López-Carrillo, Lizbeth; Rojas-García, Aurora E; Aguilar-Salinas, Alberto; Manno, Maurizio; Albores, Arnulfo

    2006-04-01

    Print workers are exposed to organic solvents, of which the systemic toxicant toluene is a main component. Toluene induces expression of cytochrome P450 2E1 (CYP2E1), an enzyme involved in its own metabolism and that of other protoxicants, including some procarcinogens. Therefore, we investigated the association between toluene exposure and the CYP2E1 response, as assessed by mRNA content in peripheral lymphocytes or the 6-hydroxychlorzoxazone (6OH-CHZ)/chlorzoxazone (CHZ) quotient (known as CHZ metabolic ratio) in plasma, and the role of genotype (5 -flanking region RsaI/PstI polymorphic sites) in 97 male print workers. The geometric mean (GM) of toluene concentration in the air was 52.80 ppm (10-760 ppm); 54% of the study participants were exposed to toluene concentrations that exceeded the maximum permissible exposure level (MPEL). The GM of urinary hippuric acid at the end of a work shift (0.041 g/g creatinine) was elevated relative to that before the shift (0.027 g/g creatinine; p < 0.05). The GM of the CHZ metabolic ratio was 0.33 (0-9.3), with 40% of the subjects having ratios below the GM. However, the average CYP2E1 mRNA level in peripheral lymphocytes was 1.07 (0.30-3.08), and CYP2E1 mRNA levels within subjects correlated with the toluene exposure ratio (environmental toluene concentration:urinary hippuric acid concentration) (p = 0.014). Genotype did not alter the association between the toluene exposure ratio and mRNA content. In summary, with further validation, CYP2E1 mRNA content in peripheral lymphocytes could be a sensitive and noninvasive biomarker for the continuous monitoring of toluene effects in exposed persons.

  4. Adsorption properties of regenerative materials for removal of low concentration of toluene.

    Science.gov (United States)

    Xie, Zhen-Zhen; Wang, Lin; Cheng, Ge; Shi, Lei; Zhang, Yi-Bo

    2016-12-01

    A specific type of material, activated carbon fiber (ACF), was modified by SiO2, and the final products ACF-x were obtained as ACF-12.5, ACF-20, ACF-40, and ACF-80 according to different dosages of tetraethoxysilane (TEOS). The modified material on the ACF surface had a significant and smooth cover layer with low content of silica from scanning electron microscope (SEM) image. The modified ACF-x showed the stronger hydrophobicity, thermal stability, and adsorption capacity, which had almost no effect in the presence of water vapor and no destruction in multiple cycles. ACF-20 was proven as the most efficient adsorbent in humid conditions. The dual-function system composed of the regenerative adsorbents and the combustion catalyst would be efficient in consecutive toluene adsorption/oxidation cycles, in which the combustion catalyst was prepared by the displacement reaction of H2PtCl6 with foam Ni. Therefore, the adsorption/catalytic oxidation could be a promising technique in the indoor air purification, especially in the case of very low volatile organic compound (VOC; toluene) concentration levels. Exploring highly effective adsorptive materials with less expensive costs becomes an urgent issue in the indoor air protection. ACF-20 modified by SiO2 with Pt/Ni catalysts shows stronger hydrophobicity, thermal stability, and adsorption capacity. This dual-function system composed of the regenerative materials and the combustion catalyst would be a promising technique in the indoor air purification, especially in the case of removal of very low concentration of toluene.

  5. 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.

  6. Acute toluene intoxication--clinical presentation, management and prognosis: a prospective observational study.

    Science.gov (United States)

    Camara-Lemarroy, Carlos Rodrigo; Rodríguez-Gutiérrez, René; Monreal-Robles, Roberto; González-González, José Gerardo

    2015-08-18

    Toluene is one of the most widely abused inhaled drugs due to its acute neurologic effects including euphoria and subsequent depression. However, dangerous metabolic abnormalities are associated to acute toluene intoxication. It has been previously reported that rhabdomyolysis and acute hepatorenal injury could be hallmarks of the condition, and could constitute risk factors for poor outcomes. The objective was to describe the clinical presentation, to characterize the renal and liver abnormalities, the management and prognosis associated to acute toluene intoxication. We prospectively assessed 20 patients that were admitted to a single center's emergency department from September 2012 to June 2014 with clinical and metabolic alterations due to acute toluene intoxication. The main clinical presentation consisted of weakness associated to severe hypokalemia and acidosis. Renal glomerular injury (proteinuria) is ubiquitous. Biliary tract injury (alkaline phosphatase and gamma-glutamyl transpeptidase elevations) disproportional to hepatocellular injury is common. Rhabdomyolysis occurred in 80% of patients, probably due to hypokalemia and hypophosphatemia. There were three deaths, all female, and all associated with altered mental status, severe acidosis, hypokalemia and acute oliguric renal failure. The cause of death was in all cases due to cardiac rhythm abnormalities. The hallmarks of acute toluene intoxication are hypokalemic paralysis and metabolic acidosis. Liver injury and rhabdomyolysis are common. On admission, altered mental status, renal failure, severe acidemia and female gender (not significant in our study, but present in all three deaths) could be associated with a poor outcome, and patients with these characteristics should be considered to be treated in an intensive care unit.

  7. Theoretical model for removal of volatile organic compound (VOC) air pollutant in trickling biofilter

    Institute of Scientific and Technical Information of China (English)

    LIAO; Qiang; (廖; 强); CHEN; Rong; (陈; 蓉); ZHU; Xun; (朱; 恂)

    2003-01-01

    This paper presents an analytical model for predicting VOC waste gas degradation in a trickling biofilter. To facilitate the analysis, the packed bed is simplified into a series of straight capillary tubes covered by the biofilm. The gas-liquid flow field through the tube is divided into the liquid film flow on the biofilm and the gas core flow in the center. The biofilm consists of a reaction free zone close to solid wall and a reaction zone beneath the liquid film. The capillary tube model accounts for the effect of mass transport resistance in the liquid film and the biofilm, the gas-liquid interfacial mass transport resistance, the biochemical reaction, and the limitation of oxygen to biochemical reaction. The liquid film thickness in the capillary tube is obtained by simultaneously solving a set of hydrodynamic equations representing the momentum transport behaviors of the gas-liquid two-phase flow. The mass transport equations are established for gas core, liquid film, and biofilm combined with biochemical kinetics equations. An iterative computation process is employed to solve the discrete equations. The predicted purification efficiencies of VOC waste gas in trickling biofilter are found to be in good agreement with the experimental data. It has been revealed that for a fixed inlet concentration of toluene, the purification efficiency of trickling biofilter decreases with the increase in gas flow rate and liquid flow rate. The purification efficiency of VOC waste gas is dominated by mass transport resistance in liquid film and biofilm. The highest biodegradation rate occurs at the inlet of waste gas in trickling biofilter.

  8. Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

    Science.gov (United States)

    Derstroff, Bettina; Hüser, Imke; Bourtsoukidis, Efstratios; Crowley, John N.; Fischer, Horst; Gromov, Sergey; Harder, Hartwig; Janssen, Ruud H. H.; Kesselmeier, Jürgen; Lelieveld, Jos; Mallik, Chinmay; Martinez, Monica; Novelli, Anna; Parchatka, Uwe; Phillips, Gavin J.; Sander, Rolf; Sauvage, Carina; Schuladen, Jan; Stönner, Christof; Tomsche, Laura; Williams, Jonathan

    2017-08-01

    During the summertime CYPHEX campaign (CYprus PHotochemical EXperiment 2014) in the eastern Mediterranean, multiple volatile organic compounds (VOCs) were measured from a 650 m hilltop site in western Cyprus (34° 57' N/32° 23' E). Periodic shifts in the northerly Etesian winds resulted in the site being alternately impacted by photochemically processed emissions from western (Spain, France, Italy) and eastern (Turkey, Greece) Europe. Furthermore, the site was situated within the residual layer/free troposphere during some nights which were characterized by high ozone and low relative humidity levels. In this study we examine the temporal variation of VOCs at the site. The sparse Mediterranean scrub vegetation generated diel cycles in the reactive biogenic hydrocarbon isoprene, from very low values at night to a diurnal median level of 80-100 pptv. In contrast, the oxygenated volatile organic compounds (OVOCs) methanol and acetone exhibited weak diel cycles and were approximately an order of magnitude higher in mixing ratio (ca. 2.5-3 ppbv median level by day, range: ca. 1-8 ppbv) than the locally emitted isoprene and aromatic compounds such as benzene and toluene. Acetic acid was present at mixing ratios between 0.05 and 4 ppbv with a median level of ca. 1.2 ppbv during the daytime. When data points directly affected by the residual layer/free troposphere were excluded, the acid followed a pronounced diel cycle, which was influenced by various local effects including photochemical production and loss, direct emission, dry deposition and scavenging from advecting air in fog banks. The Lagrangian model FLEXPART was used to determine transport patterns and photochemical processing times (between 12 h and several days) of air masses originating from eastern and western Europe. Ozone and many OVOC levels were ˜ 20 and ˜ 30-60 % higher, respectively, in air arriving from the east. Using the FLEXPART calculated transport time, the contribution of photochemical

  9. Volatile organic compounds (VOCs in photochemically aged air from the eastern and western Mediterranean

    Directory of Open Access Journals (Sweden)

    B. Derstroff

    2017-08-01

    Full Text Available During the summertime CYPHEX campaign (CYprus PHotochemical EXperiment 2014 in the eastern Mediterranean, multiple volatile organic compounds (VOCs were measured from a 650 m hilltop site in western Cyprus (34° 57′ N/32° 23′ E. Periodic shifts in the northerly Etesian winds resulted in the site being alternately impacted by photochemically processed emissions from western (Spain, France, Italy and eastern (Turkey, Greece Europe. Furthermore, the site was situated within the residual layer/free troposphere during some nights which were characterized by high ozone and low relative humidity levels. In this study we examine the temporal variation of VOCs at the site. The sparse Mediterranean scrub vegetation generated diel cycles in the reactive biogenic hydrocarbon isoprene, from very low values at night to a diurnal median level of 80–100 pptv. In contrast, the oxygenated volatile organic compounds (OVOCs methanol and acetone exhibited weak diel cycles and were approximately an order of magnitude higher in mixing ratio (ca. 2.5–3 ppbv median level by day, range: ca. 1–8 ppbv than the locally emitted isoprene and aromatic compounds such as benzene and toluene. Acetic acid was present at mixing ratios between 0.05 and 4 ppbv with a median level of ca. 1.2 ppbv during the daytime. When data points directly affected by the residual layer/free troposphere were excluded, the acid followed a pronounced diel cycle, which was influenced by various local effects including photochemical production and loss, direct emission, dry deposition and scavenging from advecting air in fog banks. The Lagrangian model FLEXPART was used to determine transport patterns and photochemical processing times (between 12 h and several days of air masses originating from eastern and western Europe. Ozone and many OVOC levels were  ∼  20 and  ∼  30–60 % higher, respectively, in air arriving from the east. Using the FLEXPART

  10. Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene.

    Science.gov (United States)

    Rene, Eldon R; Kar, Saurajyoti; Krishnan, Jagannathan; Pakshirajan, K; López, M Estefanía; Murthy, D V S; Swaminathan, T

    2015-08-01

    The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Toluene Combustion over Pd-Ce0.4Zr0.6O2 Directly Washcoated Monolithic Catalysts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A Ce0.4Zr0.6O2 washcoat was prepared using an impregnation method, which acted as a host for the active Pd component to prepare a Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst for toluene combustion.The catalyst was characterized by scanning electron microscopy (SEM), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and carbon monoxide temperature-programmed reduction (CO-TPR).It was found that the washcoat had strong vibration-shock resistance according to an ultrasonic test.The Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst calcined at 400 ℃ showed 95% toluene conversion at a temperature as low as 210 ℃.Furthermore, the lowest temperature for 95% toluene conversion was increased by 40 ℃ after the catalyst calcined at 900 ℃, indicating that the catalyst had good thermal stability.The results revealed that the developed catalyst in this study was promising for eliminating volatile organic compounds (VOCs).

  12. Source apportionment of ambient volatile organic compounds (VOCs)and their characteristics in Chengdu, southwest of China

    Science.gov (United States)

    Deng, Yuanyuan; Xie, Shaodong; Li, Jing; Li, Yaqi

    2017-04-01

    Chengdu, located in the largest basin region in the world, suffers from increasing ground-level ozone and aerosol pollutions. Volatile organic compounds (VOCs) are one of the prominent precursors of ground-level ozone and aerosols. Ambient VOCs were measured continuously using an online gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) with a time resolution of 1 hour from 28 August 2016 to 7 October 2016 at Pixian in Chengdu. 99 measurements of VOCs were conducted including 28 alkanes, 11 alkenes, 16 aromatics, 13 oxygenated VOCs (OVOCs) and 29 halocarbons, acetylene, and acetonitrile. Based on the hourly average data, positive matrix factorization (PMF) was used to better understand the emission sources of VOCs in Chengdu. The average mixing ratios of alkanes, alkenes, aromatics, OVOCs, halocarbons, acetylene, and acetonitrile were respectively 14.49 ppbv, 4.92 ppbv, 5.14 ppbv, 9.74 ppbv, 7.77 ppbv, 3.56 ppbv, and 0.43 ppbv. Six sources were extracted by using PMF model. Liquefied petroleum gas, background and petrochemical industries contributed 28%, 19%, 18% to the total ambient VOCs, respectively. Biogenic emission (14%), Gasoline vehicles (13%), Solvent use (8%) were also identified as major sources of ambient VOCs at Pixian.

  13. 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.

  14. [VOCs tax policy on China's economy development].

    Science.gov (United States)

    Liu, Chang-Xin; Wang, Yu-Fei; Wang, Hai-Lin; Hao, Zheng-Ping; Wang, Zheng

    2011-12-01

    In this paper, environmental tax was designed to control volatile organic compounds (VOCs) emissions. Computable general equilibrium (CGE) model was used to explore the impacts of environmental tax (in forms of indirect tax) on the macro-economy development at both national and sector levels. Different levels of tax were simulated to find out the proper tax rate. It is found out that imposing environmental tax on high emission sectors can cause the emission decreased immediately and can lead to negative impacts on macro-economy indicators, such as GDP (gross domestic products), total investment, total product and the whole consumption etc. However, only the government income increased. In addition, the higher the tax rate is, the more pollutants can be reduced and the worse economic effects can be caused. Consequently, it is suggested that, the main controlling policies of VOCs abatement should be mandatory orders, and low environmental tax can be implemented as a supplementary.

  15. Reassessing the atmospheric oxidation mechanism of toluene

    Science.gov (United States)

    Ji, Yuemeng; Zhao, Jun; Terazono, Hajime; Misawa, Kentaro; Levitt, Nicholas P.; Li, Yixin; Lin, Yun; Peng, Jianfei; Wang, Yuan; Duan, Lian; Pan, Bowen; Zhang, Fang; Feng, Xidan; An, Taicheng; Marrero-Ortiz, Wilmarie; Secrest, Jeremiah; Zhang, Annie L.; Shibuya, Kazuhiko; Molina, Mario J.; Zhang, Renyi

    2017-08-01

    Photochemical oxidation of aromatic hydrocarbons leads to tropospheric ozone and secondary organic aerosol (SOA) formation, with profound implications for air quality, human health, and climate. Toluene is the most abundant aromatic compound under urban environments, but its detailed chemical oxidation mechanism remains uncertain. From combined laboratory experiments and quantum chemical calculations, we show a toluene oxidation mechanism that is different from the one adopted in current atmospheric models. Our experimental work indicates a larger-than-expected branching ratio for cresols, but a negligible formation of ring-opening products (e.g., methylglyoxal). Quantum chemical calculations also demonstrate that cresols are much more stable than their corresponding peroxy radicals, and, for the most favorable OH (ortho) addition, the pathway of H extraction by O2 to form the cresol proceeds with a smaller barrier than O2 addition to form the peroxy radical. Our results reveal that phenolic (rather than peroxy radical) formation represents the dominant pathway for toluene oxidation, highlighting the necessity to reassess its role in ozone and SOA formation in the atmosphere.

  16. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    Directory of Open Access Journals (Sweden)

    OLIVIA ANCA RUSU

    2011-03-01

    Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

  17. Characterization of products from photooxidation of toluene

    Institute of Scientific and Technical Information of China (English)

    HAO Li-qing; WANG Zhen-ya; FANG Li; ZHANG Wei-jun; WANG Wei; LI Cheng-xiang; SHENG Liu-si

    2006-01-01

    Photooxidation reaction of toluene in smog chamber systems was initiated by the UV radiation of toluene/CH3ONO/NOx mixtures. The products of the photooxidation reaction of toluene and its subsequent reactions were analyzed directly utilizing Fourier transform infrared spectrometer (FTIR). Detailed assignments to FTIR spectrum of gas-phase products were given. The information of some important functional groups in the products, such as, carbonyl groups (C=O), hydroxyl groups (-OH), carboxylic acid (-COOH), C=C bonding, N-O bonding and C-H bonding (C-H), was got from this analysis. These results were compared to those analyzed by aerosol time of flight mass spectrometer (ATOFMS). It was found that there are some differences between FTIR analysis of gas-phase products and that of particle-phase, for example, the products with carbonyl groups, which were connected to unsaturated chemical bonds, was relatively higher in the gas phase, while ketones, aldehydes, carboxylic acid and organonitrates were the dominant functional groups in the aerosol-phase reaction products. The possible reaction pathways of some important products in the gas phase were also discussed.

  18. Reversible cerebral periventricular white matter changes with corpus callosum involvement in acute toluene-poisoning.

    Science.gov (United States)

    Lin, Chih-Ming; Liu, Chi-Kuang

    2015-01-01

    Substance poisoning, such as toluene intoxication, has seldom been reported in the relevant literature. The documented cerebral neuroimaging has mostly described reversible symmetrical white matter changes in both the cerebral and cerebellar hemispheres. This paper presents 2 patients with toluene poisoning, whose brain magnetic resonance imaging studies showed a similar picture that included extra involvement over the corpus callosum; however, such corpus callosum involvement has never been mentioned and is quite rare in the literature. We discussed the underlying neuropathological pathways in this article. Hopefully, these cases will provide first-line clinicians with some valuable information with regard to toluene intoxication and clinical neuroimaging presentations. Copyright © 2014 by the American Society of Neuroimaging.

  19. Benzodiazepine-like discriminative stimulus effects of toluene vapor.

    Science.gov (United States)

    Shelton, Keith L; Nicholson, Katherine L

    2013-11-15

    In vitro studies show that the abused inhalant toluene affects a number of ligand-gated ion channels.The two most consistently implicated of these are γ-aminobutyric acid type A(GABAA) receptors which are positively modulated by toluene and N-methyl-D-aspartate(NMDA) receptors which are negatively modulated by toluene. Behavioral studies also suggest an interaction of toluene with GABAA and/or NMDA receptors but it is unclear if these receptors underlie the abuse-related intoxicating effects of toluene. Seventeen B6SJLF1/J mice were trained using a two-choice operant drug discrimination procedure to discriminate 10 min of exposure to 2000 ppm toluene vapor from 10 min of exposure to air. The discrimination was acquired in a mean of 65 training sessions. The stimulus effects of 2000 ppm toluene vapor were exposure concentration-dependent but rapidly diminished following the cessation of vapor exposure. The stimulus effects of toluene generalized to the chlorinated hydrocarbon vapor perchloroethylene but not 1,1,2-trichloroethane nor the volatile anesthetic isoflurane. The competitive NMDA antagonist CGS-19755, the uncompetitive antagonist dizocilpine and the glycine-site antagonist L701,324 all failed to substitute for toluene. The classical nonselective benzodiazepines midazolam and chlordiazepoxide produced toluene-like stimulus effects but the alpha 1 subunit preferring positive GABAA modulator zaleplon failed to substitute for toluene. The barbiturates pentobarbital and methohexital and the GABAA positive modulator neurosteroid allopregnanolone did not substitute for toluene. These data suggest that the stimulus effects of toluene may be at least partially mediated by benzodiazepine-like positive allosteric modulation of GABAA receptors containing alpha 2, 3 or 5 subunits.

  20. Release of VOCs and particles during use of nanofilm spray products.

    Science.gov (United States)

    Nørgaard, Asger W; Jensen, Keld A; Janfelt, Christian; Lauritsen, Frants R; Clausen, Per A; Wolkoff, Peder

    2009-10-15

    Here, we present emission data on VOCs and particles emitted during simulated use of four commercial nanofilm spray products (NFPs) used for making easy-to-clean or self-cleaning surfaces on floors, ceramic tiles, and windows. The aim was to characterize the emitted VOCs and to provide specific source strength data for VOCs and particles released to the airduring use of the products. Containers with NFP were mounted on a spray-stand inside a closed stainless steel chamber with no air exchange. NFPs were sprayed in amounts corresponding to 1 m2 surface toward a target plate at a distance of 35 cm. Released VOCs were measured by a combination of air sampling on Tenax TA adsorbent followed by thermal desorption GC/MS and GC/FID analysis and real time measurements using a miniature membrane inlet mass spectrometer. Particles were measured using a fast mobility particle sizer and an aerosol particle sizer. A number of VOCs were identified, including small alcohols, ketones and ethers, chlorinated acetones, a perfluorinated silane, limonene, and cyclic siloxanes. The number of generated particles was on the order of 3 x 10(8) to 2 x 10(10) particles/m3 per g sprayed NFP and were dominated by nanosize particles.

  1. Stable Carbon Isotope Ratios of Phenolic Compounds in Secondary Particulate Organic Matter Formed by Photooxidation of Toluene

    CERN Document Server

    Irei, Satoshi; Huang, Lin; Auld, Janeen; Collin, Fabrice; Hastie, Donald

    2014-01-01

    Compound-specific stable carbon isotope ratios for phenolic compounds in secondary particulate organic matter (POM) formed by photooxidation of toluene were studied. Secondary POM generated by photooxidation of toluene using a continuous-flow reactor and an 8 cubic meter indoor smog chamber was collected, and then extracted with acetonitrile. Eight phenolic compounds were identified in the extracts by a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined by a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of the products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5 to 6 permil compared to the initial isotope ratio for toluene, whereas the isotope ratio for 4_nitrophenol remained the same as the initial isotope ratio for toluene. Based on the reaction mechanisms postulated in literature, stable carbon isotope ratios of these produc...

  2. 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

  3. Arid sites stakeholder participation in evaluating innovative technologies: VOC-Arid Site Integrated Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, T.S.; McCabe, G.H.; Brockbank, B.R. [and others

    1995-05-01

    Developing and deploying innovative environmental cleanup technologies is an important goal for the U.S. Department of Energy (DOE), which faces challenging remediation problems at contaminated sites throughout the United States. Achieving meaningful, constructive stakeholder involvement in cleanup programs, with the aim of ultimate acceptance of remediation decisions, is critical to meeting those challenges. DOE`s Office of Technology Development sponsors research and demonstration of new technologies, including, in the past, the Volatile Organic Compounds Arid Site Integrated Demonstration (VOC-Arid ID), hosted at the Hanford Site in Washington State. The purpose of the VOC-Arid ID has been to develop and demonstrate new technologies for remediating carbon tetrachloride and other VOC contamination in soils and ground water. In October 1994 the VOC-Arid ID became a part of the Contaminant Plume Containment and Remediation Focus Area (Plume Focus Area). The VOC Arid ID`s purpose of involving stakeholders in evaluating innovative technologies will now be carried on in the Plume Focus Area in cooperation with Site Technology Coordination Groups and Site Specific Advisory Boards. DOE`s goal is to demonstrate promising technologies once and deploy those that are successful across the DOE complex. Achieving that goal requires that the technologies be acceptable to the groups and individuals with a stake in DOE facility cleanup. Such stakeholders include groups and individuals with an interest in cleanup, including regulatory agencies, Native American tribes, environmental and civic interest groups, public officials, environmental technology users, and private citizens. This report documents the results of the stakeholder involvement program, which is an integral part of the VOC-Arid ID.

  4. Progression of neuropsychological deficits following toluene diisocyanate exposure.

    Science.gov (United States)

    Singer, R; Scott, N E

    1987-01-01

    Three wharf workers were acutely exposed to toluene diisocyanate (TDI) during an accidental chemical spill. Toluene is neurotoxic as a solvent, while cyanates can cause nervous tissue injury or death by hypoxia. Chronic symptoms which occurred following the incident included headache, fatigue, concentration problems, irritability, depression, sleep disturbance, memory and sexual dysfunction. Compared with two months post-exposure, at 16 months post-exposure Full Scale IQ dropped an average of 23 points. Results from additional neuropsychological testing at 16 months post-exposure indicated severe deficits in all three subjects in memory, manual dexterity, visuomotor tracking, mental flexibility, ability to detect figure-ground relationships, and word fluency. Nerve conduction velocity testing indicated abnormal peripheral nervous system function in two of the three workers; however, its etiology is not certain. These results may be relevant to the neurotoxicity of methyl isocyanate exposure, such as occurred in Bhopal, India, where an increasing magnitude of depression, anxiety, fatigue, restlessness, and headaches 18 months post-exposure have been reported. In general, continuing decrement in mental function without concomitant environmental exposure should be considered in neuropsychological assessment of chemical toxicity.

  5. Catalytic oxidation of volatile organic compounds (VOCs) - A review

    Science.gov (United States)

    Kamal, Muhammad Shahzad; Razzak, Shaikh A.; Hossain, Mohammad M.

    2016-09-01

    Emission of volatile organic compounds (VOCs) is one of the major contributors to air pollution. The main sources of VOCs are petroleum refineries, fuel combustions, chemical industries, decomposition in the biosphere and biomass, pharmaceutical plants, automobile industries, textile manufacturers, solvents processes, cleaning products, printing presses, insulating materials, office supplies, printers etc. The most common VOCs are halogenated compounds, aldehydes, alcohols, ketones, aromatic compounds, and ethers. High concentrations of these VOCs can cause irritations, nausea, dizziness, and headaches. Some VOCs are also carcinogenic for both humans and animals. Therefore, it is crucial to minimize the emission of VOCs. Among the available technologies, the catalytic oxidation of VOCs is the most popular because of its versatility of handling a range of organic emissions under mild operating conditions. Due to that fact, there are numerous research initiatives focused on developing advanced technologies for the catalytic destruction of VOCs. This review discusses recent developments in catalytic systems for the destruction of VOCs. Review also describes various VOCs and their sources of emission, mechanisms of catalytic destruction, the causes of catalyst deactivation, and catalyst regeneration methods.

  6. [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.

  7. Cometabolic microbial degradation of trichloroethylene in the presence of toluene

    Institute of Scientific and Technical Information of China (English)

    SUI Hong; LI Xin-Gang; XU Shi-Min1

    2004-01-01

    Trichloroethylene(TCE), a common groundwater pollutant, was cometabolized by microorganisms in the presence of toluene as a growth substrate. The effect of concentrations of toluene and TCE and temperature on biodegradation was discussed. Acclimated microorganisms degraded TCE after a lag period of 5 to 22 h depending on toluene concentrations. Approximately 60%, 90% and 64% of TCE were degraded at toluene to TCE concentration ratios of 23:1, 115:1 and 230:1, respectively. At a TCE concentration of 1.46 μg/ml, 80% of TCE and 98.4% of toluene were removed. But less degradation of TCE and toluene was observed when TCE concentration was above 48.8 μg/ml. The lag time of TCE decreased and the TCE biodegradation rates increased with the increase of temperature.

  8. Hepatic metabolism of toluene after gastrointestinal uptake in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; Mølhave, Lars; Honoré Hansen, S

    1993-01-01

    The metabolism of toluene and the influence of small doses of ethanol were measured in eight male volunteers after gastrointestinal uptake, the toluene concentration in alveolar air and the urinary excretion of hippuric acid and ortho-cresol being used as the measures of metabolism. During toluene...... exposure to 2 mg.min-1 for 3 h the alveolar toluene concentration was 0.07 (range 0-0.11) mg.m-3; exposure to 6 mg.min-1 for 30 min increased the alveolar concentration to 0.9 (range 0.03-2.6) mg.m-3. Ingestion of 0.08, 0.16, and 0.32 g of ethanol per kilogram of body weight during toluene exposure of 2 mg...... doses of ethanol inhibit toluene metabolism, and the procedure is sensitive enough to measure metabolic interactions between solvents and other xenobiotics in humans....

  9. Are biogenic emissions a significant source of summertime atmospheric toluene in rural Northeastern United States?

    Directory of Open Access Journals (Sweden)

    M. L. White

    2008-06-01

    Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequentially, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004–2006. These included: 1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet U.S. EPA summertime volatility standards, 2 local industrial emissions and 3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d−1, and did not fully account for the observed enhancements (20–50 pptv in 2004–2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d−1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d−1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  10. Performance catalytic ozonation over the carbosieve in the removal of toluene from waste air stream.

    Science.gov (United States)

    Samarghandi, Mohammad Reza; Babaee, Seyed Alireza; Ahmadian, Mohammad; Asgari, Ghorban; Ghorbani Shahna, Farshid; Poormohammadi, Ali

    2014-01-01

    Toluene is a volatile organic compound, one of 189 hazardous air pollutants (HAPs) and the most important pollutant found in most industries and indoor environments; owing to its adverse health, toluene must be treated before being released into the environment. In this research study, a continuous-flow system (including an air compressor, silica gel filters and activated charcoal, impinger, an ozone generation and a fixed bed reactor packed with the carbosieve in size 1.8-2.3 mm, specific surface: 972 m2/g,) was used. This glass reactor was 0.7 m in height; at a distance of 0.2 m from its bottom, a mesh plane was installed so as to hold the adsorbent. Moreover, 3 l/min oxygen passed through this system, 0.43 g/h ozone was prepared. The flow rate of waste airstream was 300 ml/min. The efficiency of this system for removal of toluene was compared under the same experimental conditions. Under similar conditions, performance of catalytic ozonation was better in toluene removal than that of ozonation and carbosieve alone. On average, increasing the removal efficiency was 45% at all concentrations. When carbosieve and ozone come together, their synergistic effects increased on toluene degradation. Catalytic ozonation is a suitable, high-efficient and available method for removing toluene from various concentrations of waste air stream. This process due to the short contact time, low energy consuming and making use of cheap catalysts can be used as a novel process for removing various concentrations of volatile organic compounds.

  11. Biodegradation of benzo[α]pyrene, toluene, and formaldehyde from the gas phase by a consortium of Rhodococcus erythropolis and Fusarium solani.

    Science.gov (United States)

    Morales, Paulina; Cáceres, Manuel; Scott, Felipe; Díaz-Robles, Luis; Aroca, Germán; Vergara-Fernández, Alberto

    2017-07-06

    Polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) are important indoor contaminants. Their hydrophobic nature hinders the possibility of biological abatement using biofiltration. Our aim was to establish whether the use of a consortium of Fusarium solani and Rhodococcus erythropolis shows an improved performance (in terms of mineralization rate and extent) towards the degradation of formaldehyde, as a slightly polar VOC; toluene, as hydrophobic VOC; and benzo[α]pyrene (BaP) as PAH at low concentrations compared to a single-species biofilm in serum bottles with vermiculite as solid support to mimic a biofilter and to relate the possible improvements with the surface hydrophobicity and partition coefficient of the biomass at three different temperatures. Results showed that the hydrophobicity of the surface of the biofilms was affected by the hydrophobicity of the carbon source in F. solani but it did not change in R. erythropolis. Similarly, the partition coefficients of toluene and BaP in F. solani biomass (both as pure culture and consortium) show a reduction of up to 38 times compared to its value in water, whereas this reduction was only 1.5 times in presence of R. erythropolis. Despite that increments in the accumulated CO2 and its production rate were found when F. solani or the consortium was used, the mineralization extent of toluene was below 25%. Regarding BaP degradation, the higher CO2 production rates and percent yields were obtained when a consortium of F. solani and R. erythropolis was used, despite a pure culture of R. erythropolis exhibits poor mineralization of BaP.

  12. Ultraviolet and radical oxidation of airborne VOC`s. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Heinsohn, R.J.; Spaeder, T.A.; Albano, M.T.; Schmelzle, J.P.; Fetter, R.O.

    1994-03-18

    Airborne VOC`s reactions initiated by UV radiation at selected wavelengths from 185 to 308 nm have been studied. A simplified chemical kinetic mechanism is proposed incorporating photolysis and radical reactions. The concentration of HCHO and CH{sub 3}OH were predicted as a function of time, radiation wavelength, actinic flux and initial ozone concentration. The gas velocity and HCHO concentration were predicted in a gas stream flowing over a UV bulb. Experiments were conducted in which ethanol vapor and air were irradiated by low-pressure mercury bulbs. Ethanol disappeared in an overall first-order manner and an intermediate species, believed to be acetaldehyde, appeared and then disappeared.

  13. [A new method for determination of toluene-2,4-diamine and toluene-2,6-diamine in workplace air].

    Science.gov (United States)

    Kowalska, Joanna; Jeżewska, Anna

    2017-06-27

    Toluenediamines are harmful substances. Toluene-2,4-diamine has been assigned to Carcinogen 1B hazard class, pursuant to Regulation (European Community - EC) No. 1272/2008 of the European Parliament and of the Council, and toluene- 2,6-diamine to Mutagen 2 hazard class. The main routes of exposure to toluene-2,4-diamine and toluene-2,6-diamine are via the respiratory tract and the skin. Toluene-2,4-diamine and toluene-2,6-diamine occur in the work environment in Poland. The aim of this study was to develop and validate a method for the determination of toluene-2,4-diamine and toluene-2,6-diamine that allows the simultaneous determination of their concentrations in the workplace air by personal sampling. Determination of toluene-2,4-diamine and toluene-2,6-diamine derivatives in acetonitrile were carried out by means of liquid chromatography with a diode assay detector. The method involves passing amine-containing air through sulfuric acidtreated glass fiber filter, washing out the substance settled on the filter, using water and solution of sodium hydroxide, followed by the extraction with toluene, reaction with 3,5-dinitobenzoyl chloride, replacement of dissolvent with acetonitrile and analysis of obtained solution. The method developed in this study enables the researcher to determine the content of toluene-2,4-diamine and toluene-2,6-diamine in the presence of other hazardous substances. In the specified measuring range (2.88-57.6 μg/ml) calibration curves are linear. Under the optimized conditions of determination, the limit of detection (LOD) values achieved: 51.36 ng/ml for toluene-2,4-diamine and 52.93 ng/ml for toluene-2,6-diamine. This method makes it possible to determine the concentration of toluene-2,4-diamine and toluene-2,6-diamine in the workplace air within the specified measuring range of 0.004-0.08 mg/m3 (for air sample volume of 720 l). Med Pr 2017;68(4):497-505.

  14. A new method for determination of toluene-2,4-diamine and toluene-2,6-diamine in workplace air

    Directory of Open Access Journals (Sweden)

    Joanna Kowalska

    2017-08-01

    Full Text Available Background: Toluenediamines are harmful substances. Toluene-2,4-diamine has been assigned to Carcinogen 1B hazard class, pursuant to Regulation (European Community – EC No. 1272/2008 of the European Parliament and of the Council, and toluene- 2,6-diamine to Mutagen 2 hazard class. The main routes of exposure to toluene-2,4-diamine and toluene-2,6-diamine are via the respiratory tract and the skin. Toluene-2,4-diamine and toluene-2,6-diamine occur in the work environment in Poland. The aim of this study was to develop and validate a method for the determination of toluene-2,4-diamine and toluene-2,6-diamine that allows the simultaneous determination of their concentrations in the workplace air by personal sampling. Material and Methods: Determination of toluene-2,4-diamine and toluene-2,6-diamine derivatives in acetonitrile were carried out by means of liquid chromatography with a diode assay detector. The method involves passing amine-containing air through sulfuric acidtreated glass fiber filter, washing out the substance settled on the filter, using water and solution of sodium hydroxide, followed by the extraction with toluene, reaction with 3,5-dinitobenzoyl chloride, replacement of dissolvent with acetonitrile and analysis of obtained solution. Results: The method developed in this study enables the researcher to determine the content of toluene-2,4-diamine and toluene-2,6-diamine in the presence of other hazardous substances. In the specified measuring range (2.88–57.6 μg/ml calibration curves are linear. Under the optimized conditions of determination, the limit of detection (LOD values achieved: 51.36 ng/ml for toluene-2,4-diamine and 52.93 ng/ml for toluene-2,6-diamine. Conclusions: This method makes it possible to determine the concentration of toluene-2,4-diamine and toluene-2,6-diamine in the workplace air within the specified measuring range of 0.004–0.08 mg/m3 (for air sample volume of 720 l. Med Pr 2017;68(4:497–505

  15. Alcohol induced alterations to the human fecal VOC metabolome.

    Directory of Open Access Journals (Sweden)

    Robin D Couch

    Full Text Available Studies have shown that excessive alcohol consumption impacts the intestinal microbiota composition, causing disruption of homeostasis (dysbiosis. However, this observed change is not indicative of the dysbiotic intestinal microbiota function that could result in the production of injurious and toxic products. Thus, knowledge of the effects of alcohol on the intestinal microbiota function and their metabolites is warranted, in order to better understand the role of the intestinal microbiota in alcohol associated organ failure. Here, we report the results of a differential metabolomic analysis comparing volatile organic compounds (VOC detected in the stool of alcoholics and non-alcoholic healthy controls. We performed the analysis with fecal samples collected after passage as well as with samples collected directly from the sigmoid lumen. Regardless of the approach to fecal collection, we found a stool VOC metabolomic signature in alcoholics that is different from healthy controls. The most notable metabolite alterations in the alcoholic samples include: (1 an elevation in the oxidative stress biomarker tetradecane; (2 a decrease in five fatty alcohols with anti-oxidant property; (3 a decrease in the short chain fatty acids propionate and isobutyrate, important in maintaining intestinal epithelial cell health and barrier integrity; (4 a decrease in alcohol consumption natural suppressant caryophyllene; (5 a decrease in natural product and hepatic steatosis attenuator camphene; and (6 decreased dimethyl disulfide and dimethyl trisulfide, microbial products of decomposition. Our results showed that intestinal microbiota function is altered in alcoholics which might promote alcohol associated pathologies.

  16. On-site passive flux sampler measurement of emission rates of carbonyls and VOCs from multiple indoor sources

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, Naohide [Research Institute of Science for Safety and Sustainability (RISS), National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba City, Ibaraki 305-8569 (Japan); Kai, Yuya; Mizukoshi, Atsushi; Kumagai, Kazukiyo; Okuizumi, Yumiko; Jona, Miki; Yanagisawa, Yukio [Department of Environment Systems, Institute of Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa-shi, Chiba 277-8563 (Japan); Fujii, Minoru [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba City, Ibaraki 305-8506 (Japan)

    2009-05-15

    In indoor environments with high levels of air pollution, it is desirable to remove major sources of emissions to improve air quality. In order to identify the emission sources that contribute most to the concentrations of indoor air pollutants, we used passive flux samplers (PFSs) to measure emission rates of carbonyl compounds and volatile organic compounds (VOCs) from many of the building materials and furnishings present in a room in a reinforced concrete building in Tokyo, Japan. The emission flux of formaldehyde from a desk was high (125 {mu}g/m{sup 2}/h), whereas fluxes from a door and flooring were low (21.5 and 16.5 {mu}g/m{sup 2}/h, respectively). The emission fluxes of toluene from the ceiling and the carpet were high (80.0 and 72.3 {mu}g/m{sup 2}/h, respectively), whereas that from the flooring was low (9.09 {mu}g/m{sup 2}/h). The indoor and outdoor concentrations of formaldehyde were 61.5 and 8.64 {mu}g/m{sup 3}, respectively, and those of toluene were 43.2 and 17.5 {mu}g/m{sup 3}, respectively. The air exchange rate of the room as measured by the perfluorocarbon tracer (PFT) method was 1.84/h. Taking into consideration the area of the emission sources, the carpet, ceiling, and walls were identified as the principal emission sources, contributing 24%, 20%, and 22% of the formaldehyde, respectively, and 22%, 27%, and 14% of the toluene, respectively, assuming that the emission rate from every major emission sources could be measured. In contrast, the door, the flooring, and the desk contributed little to the indoor levels of formaldehyde (1.0%, 0.54%, and 4.1%, respectively) and toluene (2.2%, 0.31%, and 0.85%, respectively). (author)

  17. Mineralization of volatile organic compounds (VOCs) over the catalyst CuO-Co3O4-CeO2 and its applications in industrial odor control

    KAUST Repository

    Somekawa, Shouichi

    2011-12-01

    Volatile organic compounds (VOCs) present at ppm levels were decomposed over the catalyst CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45 in mol) in an attempt to scale up for industrial odor control. In addition to enhancing the catalytic activity, CuO-Co3O4 and CeO2 helped, respectively, to maintain the strength of the pelleted catalysts and inhibit their sintering. Using toluene as a VOC model compound, kinetic analysis of the total oxidation to carbon dioxide was conducted. The odor emitted from paint-drying processes could be eliminated effectively using CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45) pelleted catalysts (188 ml) in a large-scale system. © 2011 Elsevier B.V. All rights reserved.

  18. Decomposition of toluene in a gliding arc discharge plasma reactor

    Energy Technology Data Exchange (ETDEWEB)

    Du Changming [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yan Jianhua [Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027 (China); Cheron, Bruno [UMR 6614 (CORIA), University of Rouen, 76821 Mont Saint Aignan (France)

    2007-11-15

    The decomposition of toluene in a gliding arc discharge (glidarc) was performed and studied. Experimental results indicate that the glidarc technology can effectively decompose toluene molecules and has bright prospects of being applied as an alternative tool to decompose volatile organic compounds. It is found that a change in the electrode material had an insignificant effect on the toluene removal efficiency. The toluene removal efficiency increases with increasing inlet gas temperature. The water vapor present in the gas mixture has a favorable effect on the toluene decomposition in the plasma. The energy efficiency is 29.46 g (kWh{sup -1}) at a relative humidity of 50% and a specific energy input of 0.26 kWh m{sup -3}, which is higher than other types of non-thermal plasmas. Too much or too little oxygen content does not favor toluene decomposition. The major gas phase products detected by FT-IR from the decomposition of toluene with air participation were CO, CO{sub 2}, H{sub 2}O and NO{sub 2}. Some brown depositions were found on the surface of the electrodes, which were polar oxygenous and nitrogenous compounds determined by the GC-MS analysis, such as benzaldehyde, benzoic acid, quinine and nitrophenol from the reaction of toluene with radicals. A possible mechanism for toluene destruction via glidarc technology is proposed and summarized.

  19. Surface acoustic wave sensing of VOCs in harsh chemical environments

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, K.B.; Martin, S.J.; Ricco, A.J.

    1993-06-01

    The measurement of VOC concentrations in harsh chemical and physical environments is a formidable task. A surface acoustic wave (SAW) sensor has been designed for this purpose and its construction and testing are described in this paper. Included is a detailed description of the design elements specific to operation in 300{degree}C steam and HCl environments including temperature control, gas handling, and signal processing component descriptions. In addition, laboratory temperature stability was studied and a minimum detection limit was defined for operation in industrial environments. Finally, a description of field tests performed on steam reforming equipment at Synthetica Technologies Inc. of Richmond, CA is given including a report on destruction efficiency of CCl{sub 4} in the Synthetica moving bed evaporator. Design improvements based on the field tests are proposed.

  20. Pulsed Corona Discharges and Their Applications in Toxic VOCs Abatement

    Institute of Scientific and Technical Information of China (English)

    MuhammadArifMalik; SalmanAkbarMalik

    1999-01-01

    plasma processes are among the emerging technologies for volatile organic compounds (VOCs) sbatoment. Both thermal plasmas and non-equil[brimn plasmas (cold plasmas) are being developed for VOCs clesnup. Particularly, pulsed corona discharges offer several edvantages over conventional VOCs abatement tochniqvee, To optimize the existing technology and to developit further, there is need to understand the mechanlsms involved in plasma chemical reacticms, Furthermore, it is strongly desirable to be able to predict the behavior of new VOCs in non-equillbrlum plasma enviromuent from the data known for a few representative oompounds, Pulsed corona discharge technique is introduced here with dtafion of refevant literature, Fundamental principfes,useful for predicting the VOCs' decomposition behavior, have been worked out from the published literature. Latest developments in the area, targeted to minimize the enersy losses, improve the VOCs destruction efficiency and reduce the generation of unwanted organic and inorganic by-products, are presented.

  1. Gaseous VOCs rapidly modify particulate matter and its biological effects - Part 2: Complex urban VOCs and model PM

    Science.gov (United States)

    Ebersviller, S.; Lichtveld, K.; Sexton, K. G.; Zavala, J.; Lin, Y.-H.; Jaspers, I.; Jeffries, H. E.

    2012-12-01

    modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh"), or in reacted ("Aged") complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only- and PM-only-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NOx mixture. For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemical measurements demonstrate the temporal evolution of oxidized species, with a corresponding increase in toxicity observed from exposed cells. The largest increase in gas-phase toxicity was observed in the two "Aged" VOC exposures. The largest increase in particle-phase toxicity was observed in the "Aged" VOC exposure with the addition of PM after sunset. These results are a clear demonstration that the findings from Part 1 can be extended to the complex urban oxidized environment. This further demonstrates that the atmosphere itself cannot be ignored as a source of toxic species when establishing the risks associated with exposure to PM. Because gases and PM are transported and deposited differently within the atmosphere and lungs, these results have significant consequences. In the next (and final) part of the study, testing is further applied to systems with real diesel exhaust, including primary PM from a vehicle operated with

  2. Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 2: Complex urban VOCs and model PM

    Directory of Open Access Journals (Sweden)

    S. Ebersviller

    2012-03-01

    Full Text Available This is the second study in a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOCs, particulate matter (PM, and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber, both in the dark and in sunlight. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of gas-only- and PM-only-biological effects, using cultured human lung cells as model living receptors. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects from cells exposed to chamber air relative to cells exposed to clean air. Our exposure systems permit side-by-side, gas-only- and PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure for either gases or PM.

    In Part 1 (Ebersviller et al., 2012a, we demonstrated the existence of PM "effect modification" (NAS, 2004 for the case of a single gas-phase toxicant and an inherently non-toxic PM (mineral oil aerosol, MOA. That is, in the presence of the single gas-phase toxicant in the dark, the initially non-toxic PM became toxic to lung cells in the PM-only-biological exposure system. In this Part 2 study, we used sunlit-reactive systems to create a large variety of gas-phase toxicants from a complex mixture of oxides of nitrogen and 54 VOCs representative of those measured in US city air. In these mostly day-long experiments, we have designated the period in the dark just after injection (but before sunrise as the "Fresh" condition and the period in the dark after sunset as the "Aged" condition. These two conditions were used to expose cells and to collect chemical characterization samples. We used the same inherently non-toxic PM from the Part 1 study as the

  3. Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 2: Complex urban VOCs and model PM

    Directory of Open Access Journals (Sweden)

    H. E. Jeffries

    2012-12-01

    for "effect modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh", or in reacted ("Aged" complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only- and PM-only-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NOx mixture. For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemical measurements demonstrate the temporal evolution of oxidized species, with a corresponding increase in toxicity observed from exposed cells. The largest increase in gas-phase toxicity was observed in the two "Aged" VOC exposures. The largest increase in particle-phase toxicity was observed in the "Aged" VOC exposure with the addition of PM after sunset. These results are a clear demonstration that the findings from Part 1 can be extended to the complex urban oxidized environment. This further demonstrates that the atmosphere itself cannot be ignored as a source of toxic species when establishing the risks associated with exposure to PM. Because gases and PM are transported and deposited differently within the atmosphere and lungs, these results have significant consequences. In the next (and final part of the study, testing is further applied to systems with real diesel exhaust, including primary PM from a

  4. Promotion of noise-induced cochlear injury by toluene and ethylbenzene in the rat.

    Science.gov (United States)

    Fechter, Laurence D; Gearhart, Caroline; Fulton, Sherry; Campbell, Jerry; Fisher, Jeffrey; Na, Kwangsam; Cocker, David; Nelson-Miller, Alisa; Moon, Patrick; Pouyatos, Benoit

    2007-08-01

    Ethylbenzene + toluene are known individually to have ototoxic potential at high exposure levels and with prolonged exposure times generally of 4-16 weeks. Both ethylbenzene + toluene are minor constituents of JP-8 jet fuel; this fuel has recently been determined to promote susceptibility to noise-induced hearing loss. Therefore, the current study evaluates the ototoxic potential of combined exposure to ethylbenzene + toluene exposure in a ratio calculated from the average found in three laboratories. Rats received ethylbenzene + toluene by inhalation and half of them were subjected simultaneously to an octave band of noise (OBN) of 93-95 dB. Another group received only the noise exposure which was designed to produce a small, but permanent auditory impairment while an unexposed control group was also included. In two separate experiments, exposures occurred either repeatedly on 5 successive days for 1 week or for 5 days on 2 successive weeks to 4000 mg/m(3) total hydrocarbons for 6 h based upon initial pilot studies. The concentration of toluene was 400 ppm and the concentration of ethylbenzene was 660 ppm. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. Following completion of these tests, the organs of Corti were dissected to permit evaluation of hair cell loss. The uptake and elimination of the solvents was assessed by harvesting key organs at two time points following ethylbenzene + toluene exposure from additional rats not used for auditory testing. Similarly, glutathione (GSH) levels were measured in light of suggestions that oxidative stress might result from solvent-noise exposures. Ethylbenzene + toluene exposure by itself at 4000 mg/m(3) for 6 h did not impair cochlear function or yield a loss of hair cells. However, when combined with a 93-dB OBN exposure combined solvent + noise did yield a loss in auditory function and a clear potentiation of outer hair cell death

  5. Personal exposures and microenvironment concentrations of PM 2.5, VOC, NO 2 and CO in Oxford, UK

    Science.gov (United States)

    Lai, H. K.; Kendall, M.; Ferrier, H.; Lindup, I.; Alm, S.; Hänninen, O.; Jantunen, M.; Mathys, P.; Colvile, R.; Ashmore, M. R.; Cullinan, P.; Nieuwenhuijsen, M. J.

    Between 1998 and 2000 in Oxford, UK, simultaneous personal exposures and microenvironmental measurements (home indoor, home outdoor and work indoor) to fine particulate matters PM 2.5, volatile organic compounds (VOC), nitrogen dioxide (NO 2) and carbon monoxide (CO) were carried out once per person among 50 adults over a 48-h period. Thirty-seven elements in PM 2.5 and 30 different VOCs were analysed. Questionnaires were distributed to record their time-activity patterns and exposure-related information. Results showed that participants spent more time (89.5%) in all indoors than in other microenvironments. Geometric mean (GM) of personal and home indoor levels of PM 2.5, 14 elements (aluminium, arsenic, bromine, calcium, copper, iron, gallium, potassium, sodium, phosphorus, lead, selenium, silicon, titanium), total VOC (TVOC) and 8 individual compounds (nonane, decane, undecane, trimethylbenzene, toluene, benzaldehyde, alpha-pinene and d-limonene) were over 20% higher than their GM outdoor levels. Those of NO 2, 5 aromatic VOCs (benzene, o-xylene, ethylbenzene, propylbenzene, m, p-xylene) and 5 other elements (chlorine, magnesium, manganese, sulphur, zinc) were close to their GM outdoor levels. For PM 2.5 and TVOC, personal exposures and residential indoor levels (in GM) were about 2 times higher among the tobacco-smoke exposed group compared to the non-smoke exposed group, suggesting that smoking is an important determinant of these exposures. Determinants for CO were visualised by real-time monitoring, and we showed that the peak levels of personal exposure to CO were associated with smoking, cooking and transportation activities. Moderate to good correlations were only found between the personal exposures and residential indoor levels for both PM 2.5 ( r=0.60, pp=0.003).

  6. Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

    OpenAIRE

    Bennett, Joan W.; Arati A. Inamdar

    2015-01-01

    Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpe...

  7. Outdoor, indoor, and personal exposure to VOCs in children.

    Science.gov (United States)

    Adgate, John L; Church, Timothy R; Ryan, Andrew D; Ramachandran, Gurumurthy; Fredrickson, Ann L; Stock, Thomas H; Morandi, Maria T; Sexton, Ken

    2004-10-01

    We measured volatile organic compound (VOC) exposures in multiple locations for a diverse population of children who attended two inner-city schools in Minneapolis, Minnesota. Fifteen common VOCs were measured at four locations: outdoors (O), indoors at school (S), indoors at home (H), and in personal samples (P). Concentrations of most VOCs followed the general pattern O approximately equal to S long-term health risks from children's exposure to these compounds.

  8. One-step phenol production from a water-toluene mixture using radio frequency in-liquid plasma

    Science.gov (United States)

    Muhammad, AGUNG; Shinfuku, NOMURA; Shinobu, MUKASA; Hiromichi, TOYOTA; Otsuka, KAZUHIKO; Hidekazu, GOTO

    2017-05-01

    The objectives of this research were to understand the process of converting toluene into phenol in a one-step process directly from a water-toluene mixture using the plasma in-liquid method. Experiments were conducted using 27.12 MHz radio frequency (RF) in-liquid plasma to decompose a solution of 30% toluene. Based on the experimental results as evaluated using gas chromatography-mass spectrometry (GC-MS), along with additional analysis by the Gaussian calculation, density functional theory (DFT) hybrid exchange-correlational functional (B3LYP) and 6-311G basis, the phenol generated from toluene was quantified including any by-products. In the experiment, it was found that OH radicals from water molecules produced using RF in-liquid plasma play a significant role in the chemical reaction with toluene. The experimental results suggest that phenol can be directly produced from a water-toluene mixture. The maximum phenol yields were 0.0013% and 0.0038% for irradiation times of 30 s and 60 s, respectively, at 120 W.

  9. CYP2E1 epigenetic regulation in chronic, low-level toluene exposure: Relationship with oxidative stress and smoking habit.

    Science.gov (United States)

    Jiménez-Garza, Octavio; Baccarelli, Andrea A; Byun, Hyang-Min; Márquez-Gamiño, Sergio; Barrón-Vivanco, Briscia Socorro; Albores, Arnulfo

    2015-08-01

    CYP2E1 is a versatile phase I drug-metabolizing enzyme responsible for the biotransformation of most volatile organic compounds, including toluene. Human toluene exposure increases CYP2E1 mRNA and modifies its activity in leucocytes; however, epigenetic implications of this interaction have not been investigated. To determine promoter methylation of CYP2E1 and other genes known to be affected by toluene exposure. We obtained venous blood from 24 tannery workers exposed to toluene (mean levels: 10.86+/-7mg/m(3)) and 24 administrative workers (reference group, mean levels 0.21+/-0.02mg/m(3)) all of them from the city of León, Guanajuato, México. After DNA extraction and bisulfite treatment, we performed PCR-pyrosequencing in order to measure methylation levels at promoter region of 13 genes. In exposed group we found significant correlations between toluene airborne levels and CYP2E1 promoter methylation (r=-.36, ptoluene-exposed smokers compared to nonsmokers (p=0.009). We also observed significant correlations for CYP2E1 promoter methylation with GSTP1 and SOD1 promoter methylation levels (r=-.37, ptoluene exposure. People co-exposed to toluene and tobacco smoke are in higher risk due to a possible CYP2E1 repression. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Effects of cold temperature and ethanol content on VOC emissions from light-duty gasoline vehicles

    Science.gov (United States)

    Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle...

  11. 40 CFR 60.112b - Standard for volatile organic compounds (VOC).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds... organic compounds (VOC). (a) The owner or operator of each storage vessel either with a design capacity... for Volatile Organic Liquid Storage Vessels (Including Petroleum Liquid Storage Vessels) for...

  12. Effects of cold temperature and ethanol content on VOC emissions from light-duty gasoline vehicles

    Science.gov (United States)

    Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle...

  13. 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.

  14. Use of mass spectrometric methods for field screening of VOC`s

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.C.

    1994-11-01

    While mass spectrometric (MS) methods of chemical analysis, particularly gas chromatography-mass spectrometry (GC/MS), have been the mainstay of environmental organic analytical techniques in the laboratory through the use of EPA and other standard methods, field implementation is relatively rare. Instrumentation and methods now exist for utilizing MS and GC/MS techniques in the field for analysis of VOC`s in gas phase, aqueous, and soil media. Examples of field investigations utilizing HP 5971A and Viking SpectraTrak systems for analysis of VOC`s in all three media will be presented. Mass spectral methods were found to offer significant advantages in terms of speed of analysis and reliability of compound identification over field gas chromatography (GC) methods while preserving adequate levels of detection sensitivity. The soil method in particular provides a method for rapid in-field analysis of methanol preserved samples thus minimizing the problem of volatiles loss which typically occurs with routine use of the EPA methods and remote analysis. The high cost of MS instrumentation remains a major obstacle to more widespread use.

  15. Development of biogenic VOC emission inventories for the boreal forest

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, V.

    2008-07-01

    . For the first time, Scots pine was found to emit also sesquiterpenes and 2-methyl- 3-buten-2-ol (MBO), with maximum emissions in the summer months. According to the model calculations the main compounds emitted by the boreal forest throughout the growing season in Finland are alpha- and beta-pinene and DELTA3-carene, with a strong contribution of sabinene by the deciduous trees in summer and autumn. The emissions follow the course of the temperature and are highest in the south boreal zone with a steady decline towards the north. The isoprene emissions from the boreal forest are fairly low - the main isoprene emitters are the low emitting Norway spruce and the high emitting willow and aspen, whose foliage, however, only represents a very small percentage of the boreal leaf biomass. This work also includes the first estimate of sesquiterpene emissions from the boreal forest. The sesquiterpene emissions initiate after midsummer and are of the same order of magnitude as the isoprene emissions. At the annual level, the total biogenic emissions from the forests in Finland are approximately twice the anthropogenic VOC emissions. (orig.)

  16. HYDROGEN AND VOC RETENTION IN WASTE BOXES

    Energy Technology Data Exchange (ETDEWEB)

    PACE ME; MARUSICH RM

    2008-11-21

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741, 2003) identifies derived safety controls to prevent or mitigate the risks of a single-container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes. The study evaluates the accumulation of hydrogen and VOCs within the waste box and the transport of these gases and vapors out of the waste box. To perform the analysis, there were numerous and major assumptions made regarding the generation rate and the transport pathway dimensions and their number. Since there is little actual data with regards to these assumptions, analyses of three potential configurations were performed to obtain some indication of the bounds of the issue (the concentration of hydrogen or flammable VOCs within a waste box). A brief description of each of the three cases along with the results of the analysis is summarized.

  17. On-road emission characteristics of VOCs from light-duty gasoline vehicles in Beijing, China

    Science.gov (United States)

    Cao, Xinyue; Yao, Zhiliang; Shen, Xianbao; Ye, Yu; Jiang, Xi

    2016-01-01

    This study is the third in a series of three papers aimed at characterizing the VOC emissions of vehicles in Beijing. In this study, 30 light-duty vehicles fueled with gasoline were evaluated using a portable emission measurement system (PEMS) as they were driven on a predesigned, fixed test route. All of the tested vehicles were rented from private vehicle owners and spanned regulatory compliance guidelines ranging from Pre-China I to China IV. Alkanes, alkenes, aromatics and some additional species in the exhaust were collected in Tedlar bags and analyzed using gas chromatography/mass spectrometry (GC-MS). Carbonyls were collected on 2,4-dinitrophenyhydrazine (DNPH) cartridges and analyzed using high-performance liquid chromatography (HPLC). Overall, 74 VOC species were detected from the tested vehicles, including 22 alkanes, 6 alkenes, 1 alkyne, 16 aromatics, 3 cyclanes, 10 halohydrocarbons, 12 carbonyls and 4 other compounds. Alkanes, aromatics and carbonyls were the dominant VOCs with weight percentages of approximately 36.4%, 33.1% and 17.4%, respectively. The average VOC emission factors and standard deviations of the Pre-China I, China I, China II, China III and China IV vehicles were 469.3 ± 200.1, 80.7 ± 46.1, 56.8 ± 37.4, 25.6 ± 11.7 and 14.9 ± 8.2 mg/km, respectively, which indicated that the VOC emissions significantly decreased under stricter vehicular emission standards. Driving cycles also influenced the VOC emissions from the tested vehicles. The average VOC emission factors based on the travel distances of the tested vehicles under urban driving cycles were greater than those under highway driving cycles. In addition, we calculated the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) method. The results of this study will be helpful for understanding the true emission levels of light-duty gasoline vehicles and will provide information for controlling VOC emissions from vehicles in Beijing, China.

  18. 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.

  19. 21 CFR 520.580 - Dichlorophene and toluene capsules.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dichlorophene and toluene capsules. 520.580 Section 520.580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dichlorophene and toluene capsules. (a) Specifications. Each soft gelatin capsule contains 50 milligrams of...

  20. Preclinical characterization of toluene as a non-classical hallucinogen drug in rats: participation of 5-HT, dopamine and glutamate systems.

    Science.gov (United States)

    Rivera-García, María Teresa; López-Rubalcava, Carolina; Cruz, Silvia L

    2015-10-01

    Toluene is a misused inhalant with hallucinogenic properties and complex effects. Toluene blocks N-methyl-D-aspartate (NMDA) receptors, releases dopamine (DA), and modifies several neurotransmitter levels; nonetheless, the mechanism by which it produces hallucinations is not well characterized. This study aims (a) to study toluene's effects on the 5-HT2A-mediated head-twitch response (HTR), dopamine (DA), and serotonin (5-HT) tissue levels in discrete brain regions; (b) to compare the actions of toluene, ketamine, and 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI) on HTR; and (c) to study the pharmacological blockade of toluene's and ketamine's effects by selective drugs. Independent groups of rats inhaled toluene (500-12,000 ppm) for 30 min during which the occurrence of serotonergic signs was analyzed. Brains were obtained after exposure to determine DA and 5-HT levels by HPLC. Toluene concentration-dependently induced HTR. Other serotonin syndrome signs were evident at high concentrations. Toluene (4000 and 8000 ppm), and ketamine (3 and 10 mg/kg), significantly increased 5-HT levels in the frontal cortex (FC) striatum, hippocampus, and brain stem, as well as DA levels in the striatum and FC. Pretreatment with ketanserin (5HT2A/2C receptor antagonist), M100907 (selective 5-HT2A receptor antagonist), D-serine (co-agonist of the NMDA receptor glycine site), and haloperidol (D2 receptor antagonist) significantly decreased toluene's and ketamine's actions. The 5HT1A receptor antagonist WAY100635 had no effect. Toluene stimulates 5HT2A and 5HT2C receptors, and increases 5-HT and DA levels. These actions are similar to those produced by ketamine and involve activation of a complex neurotransmitter network that includes NMDA receptor antagonism.

  1. Chemical speciation and anthropogenic sources of ambient volatile organic compounds(VOCs)during summer in Beijing,2004

    Institute of Scientific and Technical Information of China (English)

    LU Sihua; LIU Ying; SHAO Min; HUANG Shan

    2007-01-01

    Volatile organic compounds(VOCs)were measured at six sites in Beijing in August,2004.Up to 148 VOC species,including C3 to C12 alkanes,C3 to C11 alkenes,C6 to C12 aromatics,and halogenated hydrocarbons,were quantified.Although the concentrations differed at the sites,the chemical compositions were similar,except for the Tongzhou site where aromatics were significantly high in the air.Based on the source profiles measured from previous studies,the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance(CMB)model.The results show that urban VOCs are predominant from mobile source emissions,which contribute more than 50% of the VOCs(in mass concentrations)to ambient air at most sites.Other important sources are gasoline evaporation,painting,and solvents.The exception is at the Tongzhou site where vehicle exhaust,painting,and solvents have about equal contribution,around 35% of the ambient VOC concentration.As the receptor model is not valid for deriving the sources of reactive species,such as isoprene and 1,3-butadiene,other methodologies need to be further explored.

  2. Is toluene diamine a sensitizer and is there cross-reactivity between toluene diamine and toluene diisocyanate?

    Science.gov (United States)

    Vanoirbeek, Jeroen A J; De Vooght, Vanessa; Synhaeve, Nicholas; Nemery, Benoit; Hoet, Peter H M

    2009-06-01

    Toluene diamine (TDA) is formed when toluene diisocyanate (TDI), a potent sensitizer, comes in contact with an aqueous environment. The sensitizing capacity of TDA and the cross-reactivity between TDI and TDA are unknown. TDA (5-25%) and TDI (0.3%), dissolved in acetone/olive oil (AOO) (4:1) were tested in the mouse local lymph node assay (LLNA). To determine the capacity of TDA to elicit an asthmatic response and to determine the cross-reaction with TDI, a locally developed experimental mouse model of chemical-induced asthma was used. On days 1 and 8, BALB/c mice received 20 microl of TDI (0.3%), TDA (20%), or AOO (4:1) on each ear. On day 15, they received an intranasal instillation of TDI (0.1%), TDA (0.5%) or AOO (3:2). The EC(3) of TDA in the LLNA is 19%. In the model of chemical-induced asthma, TDI induced a ventilatory response [increased Penh after challenge; increased airway hyperreactivity (AHR)], inflammatory changes (bronchoalveolar lavage neutrophils), and immunological changes (increased CD19(+) lymphocytes, IL-4 and total serum IgE), whereas TDA did not show any of these responses. Mice sensitized with TDI and challenged with TDA also did not show any airway or inflammatory response, although they had increased levels of total serum IgE. Mice sensitized with TDA and challenged with TDI did not show any response. According to the classification of sensitizers in the LLNA, TDA is a weak dermal sensitizer. In the experimental mouse model of chemical-induced asthma, TDA does not act as a respiratory sensitizer, at the concentration used. No cross-reactivity between TDI and TDA was found.

  3. The solubility of toluene in aqueous salt solutions.

    Science.gov (United States)

    Poulson, S; Harrington, R; Drever, J

    1999-03-01

    The solubility of toluene has been measured in distilled water, and in various inorganic salt solutions. Values of the Setschenow constant, K(S), which quantify toluene solubility versus salt concentration, have been determined for each salt. Values of K(S) are compared to the activity of water for the salt solutions. Data from this study, consistent with earlier data, suggests that the effects of salts upon toluene solubility are non-additive. This contrasts the additive behavior of inorganic salts upon the solubility of nonpolar organic compounds, such as benzene and naphthalene, reported in the literature. Specific interaction between slightly polar toluene and ions in solution is suggested as a possible explanation for the non-additive effect of salts on the solubility of toluene.

  4. Comparative studies on toluene removal and pressure drop in biofilters using different packing materials.

    Science.gov (United States)

    Ryu, Hee Wook; Kim, So Jung; Cho, Kyung Suk

    2010-05-01

    To select the best available packing material for malodorous organic gases such as toluene and benzene, biofilter performance was compared in biofilters employed different packing materials including porous ceramic (celite), Jeju scoria (lava), a mixture of granular activated carbon (GAC) and celite (GAC/celite), and cubic polyurethane foam (PU). A toluene-degrading bacterium, Stenotrophomonas maltophilia T3-c, was used as the inoculum. The maximum elimination capacities in the celite, lava, and GAC/celite biofilters were 100, 130, and 110 gm(-3) hr(-1), respectively. The elimination capacity for the PU biofilter was approximately 350 g m(-3) hr(-1) at an inlet loading of approximately 430 g m(-3) hr(-1), which was 2 to 3.5 times higher than for the other biofilters. The pressure drop gradually increased in the GAC/ celite, celite and lava biofilters after 23 day due to bacterial over-growth, and the toluene removal efficiency remarkably decreased with increasing pressure drop. Backwashing method was not effective for the control of biomass in these biofilters. In the PU biofilter however, backwashing allowed maintenance of a pressure drop of 1 to 3 mm H2O m(-1) and a removal efficiency of > 80%, indicating that the PU was the best packing material for toluene removal among the packing materials tested.

  5. Selective Production of Toluene from Biomass-Derived Isoprene and Acrolein.

    Science.gov (United States)

    Dai, Tao; Li, Changzhi; Zhang, Bo; Guo, Haiwei; Pan, Xiaoli; Li, Lin; Wang, Aiqin; Zhang, Tao

    2016-12-20

    Toluene is a basic chemical that is currently produced from petroleum resources. In this paper, we report a new route for the effective synthesis of toluene from isoprene and acrolein, two reactants readily available from biomass, through a simple two-step reaction. The process includes Diels-Alder cycloaddition of isoprene and acrolein in a Zn-containing ionic liquid at room temperature to produce methylcyclohex-3-enecarbaldehydes (MCHCAs) as intermediates, followed by M (M=Pt, Pd, Rh)/Al2 O3 -catalyzed consecutive dehydrogenation-decarbonylation of the MCHCAs at 573 K to generate toluene with an overall yield up to 90.7 %. Model reactions indicated that a synergistic inductive effect of the C=C double bond and the aldehyde group in MCHCA plays a key role in initiating the consecutive dehydrogenation-decarbonylation, and that methyl benzaldehydes are the key intermediates in the gas-phase transformation of MCHCAs. Microcalorimetric adsorption of CO on different catalysts showed that decarbonylation of the substrate occurs more likely on the strong adsorption sites. To the best of our knowledge, it is the first report of Pt/Al2 O3 -catalyzed consecutive dehydrogenation-decarbonylation of a given compound in one reactor. This work provides a highly efficient and environmental friendly route to toluene by utilizing two compounds that can be prepared from biomass. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. NEW SOIL VOC SAMPLERS: EN CORE AND ACCU CORE SAMPLING/STORAGE DEVICES FOR VOC ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Susan S. Sorini; John F. Schabron; Joseph F. Rovani Jr

    2006-06-01

    Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An ASTM International (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis and specifies sample storage in the En Core sampler at 4 {+-} 2 C for up to 48 hours; -7 to -21 C for up to 14 days; or 4 {+-} 2 C for up to 48 hours followed by storage at -7 to -21 C for up to five days. This report discusses activities performed during the past year to promote and continue acceptance of the En Core samplers based on their performance to store soil samples for VOC analysis. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a sampling tool for collecting and storing subsurface soil samples for VOC analysis is not available. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core{trademark} sampler, is designed so that a soil sample can be collected below the surface using a dual-tube penetrometer and transported to the laboratory for analysis in the same container. Laboratory testing of the current Accu Core design shows that the device holds low-level concentrations of VOCs in soil samples during 48-hour storage at 4 {+-} 2 C and that the device is ready for field evaluation to generate additional performance data. This report discusses a field validation exercise that was attempted in Pennsylvania in 2004 and activities being performed to plan and conduct a field validation study in 2006. A draft ASTM

  7. SUBSTRATE EFFECTS ON VOC EMISSIONS FROM A LATEX PAINT

    Science.gov (United States)

    The effects of two substrates -- a stainless steel plate and a gypsum board -- on the volatile organic compound (VOC) emissions from a latex paint were evaluated by environmental chamber tests. It was found that the amount of VOCs emitted from the painted stainless steel was 2 to...

  8. 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...

  9. Direct measurement of VOC diffusivities in tree tissues

    DEFF Research Database (Denmark)

    Baduru, K.K.; Trapp, Stefan; Burken, Joel G.

    2008-01-01

    fundamental terminal fate processes for VOCs that have been translocated from contaminated soil or groundwater, and diffusion constitutes the mass transfer mechanism to the plant−atmosphere interface. Therefore, VOC diffusion through woody plant tissues, that is, xylem, has a direct impact on contaminant fate...

  10. Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

    Science.gov (United States)

    Bennett, Joan W; Inamdar, Arati A

    2015-09-22

    Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that "volatoxin" might be a useful term to describe biogenic volatile compounds with toxigenic properties.

  11. Are Some Fungal Volatile Organic Compounds (VOCs Mycotoxins?

    Directory of Open Access Journals (Sweden)

    Joan W. Bennett

    2015-09-01

    Full Text Available Volatile organic compounds (VOCs are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that “volatoxin” might be a useful term to describe biogenic volatile compounds with toxigenic properties.

  12. CYP2E1 epigenetic regulation in chronic, low-level toluene exposure: Relationship with oxidative stress and smoking habit

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Garza, Octavio, E-mail: ojimenezgarza@ugto.mx [Health Sciences Division, University of Guanajuato Campus León, Blvd. Puente del Milenio 1001, Fracción del Predio San Carlos, C.P. 37670 León, Guanajuato (Mexico); Baccarelli, Andrea A.; Byun, Hyang-Min [Laboratory of Environmental Epigenetics, Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115 (United States); Márquez-Gamiño, Sergio [Health Sciences Division, University of Guanajuato Campus León, Blvd. Puente del Milenio 1001, Fracción del Predio San Carlos, C.P. 37670 León, Guanajuato (Mexico); Barrón-Vivanco, Briscia Socorro [Environmental Toxicology and Pollution Laboratory, Nayarit Autonomous University, Av. Ciudad de la Cultura s/n, “Amado Nervo”, Tepic, Nayarit C.P. 63155 (Mexico); Albores, Arnulfo [Department of Toxicology, CINVESTAV, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, 07360 Mexico DF (Mexico)

    2015-08-01

    Background: CYP2E1 is a versatile phase I drug-metabolizing enzyme responsible for the biotransformation of most volatile organic compounds, including toluene. Human toluene exposure increases CYP2E1 mRNA and modifies its activity in leucocytes; however, epigenetic implications of this interaction have not been investigated. Goal: To determine promoter methylation of CYP2E1 and other genes known to be affected by toluene exposure. Methods: We obtained venous blood from 24 tannery workers exposed to toluene (mean levels: 10.86 +/− 7 mg/m{sup 3}) and 24 administrative workers (reference group, mean levels 0.21 +/− 0.02 mg/m{sup 3}) all of them from the city of León, Guanajuato, México. After DNA extraction and bisulfite treatment, we performed PCR-pyrosequencing in order to measure methylation levels at promoter region of 13 genes. Results: In exposed group we found significant correlations between toluene airborne levels and CYP2E1 promoter methylation (r = − .36, p < 0.05), as well as for IL6 promoter methylation levels (r = .44, p < 0.05). Moreover, CYP2E1 promoter methylation levels where higher in toluene-exposed smokers compared to nonsmokers (p = 0.009). We also observed significant correlations for CYP2E1 promoter methylation with GSTP1 and SOD1 promoter methylation levels (r = − .37, p < 0.05 and r = − .34, p < 0.05 respectively). Conclusion: These results highlight the importance of considering CYP2E1 epigenetic modifications, as well as its interactions with other genes, as key factors for unraveling the sub cellular mechanisms of toxicity exerted by oxidative stress, which can initiate disease process in chronic, low-level toluene exposure. People co-exposed to toluene and tobacco smoke are in higher risk due to a possible CYP2E1 repression. - Highlights: • We investigated gene-specific methylation in persons chronically exposed to toluene. • In a previous study, a reduced CYP2E1 activity was observed in these participants. • CYP2E1

  13. Molecular Probes: A Tool for Studying Toxicity of VOCs to P.Putida F1

    Science.gov (United States)

    Singh, R.; Olson, M. S.

    2007-12-01

    Volatile Organic Compounds (VOCs) are of great concern in ground water remediation, and are generally present in the form of NAPLs in subsurface environments. Among the various treatment technologies, in situ bioremediation is one of the most effective and low-cost treatment options. Many soil bacteria are reported to degrade these organic contaminants via metabolism (using them as a source of carbon to derive energy) or co- metabolism up to certain concentrations. However, larger concentrations of these contaminants are toxic to bacteria. Thus, in order to achieve successful bioremediation, it is important to determine the optimal concentrations of various contaminants that is beneficial for the activity and survival of degrading bacteria. The purpose of this study is to develop a novel method for toxicity analyses of VOC contaminants to the soil bacteria that degrade them. The present study is based on a two-color fluorescence assay of bacterial viability which facilitates actual counting of live and dead bacteria. Pseudomonas putida F1 cells were labeled with a LIVE/DEAD® BacLightTM bacterial viability kit (Invitrogen), which consists of a mixture of two dyes, SYTO 9 and propidium iodide, each with a different ability to penetrate healthy bacterial cells. Live cells stain green whereas propidium iodide (red dye) only penetrates cells with compromised membranes that are considered dead or dying. Stained cells were exposed to different concentrations of trichloroethylene (TCE) and toluene in sealed vials. Change in the concentrations of green and red cells were monitored over the time using fluorescence microscopy. UTHSCSA ImageTool software was used to count the live and dead cells in the images. It was observed that live (green) cell concentrations decreased and dead/damaged (red) cell concentrations increased over time when cells were exposed to TCE. No significant changes were observed in control experiments. Death rate constants calculated based on live cell

  14. Nieuwsgaring in Batavia tijdens de VOC

    Directory of Open Access Journals (Sweden)

    Adrienne Zuiderweg

    2010-12-01

    Full Text Available  The board members of the Dutch East India Company (1602-1795, the Heren Zeventien, promulgated various decrees in which they forbade to bring out information regarding their colonies in the Dutch East Indies and Batavia in letters, manuscripts and printed matter. But in Batavia some inventive Company servants and even staff members got around these regulations, as did some printers in Holland. They published newspapers like Bataviase Nouvelles and Vendu-Nieuws, and also the specialized journal Verhandelingen van het Bataviaasch Genootschap. The initiators of this journal joined hands with the Dutch world of learning and its journals. This article provides an overview of early journalism in the Dutch East Indies and thus contributes to the reconstruction of the literary and cultural climate in Batavia at the time of the VOC.

  15. The indoor volatile organic compound (VOC) characteristics and source identification in a new university campus in Tianjin, China.

    Science.gov (United States)

    Kang, Jian; Liu, Junjie; Pei, Jingjing

    2017-06-01

    This study investigates the volatile organic compounds (VOCs) constituents and concentration levels on a new university campus, where all of the buildings including classrooms and student dormitories were newly built and decorated within 1 year. Investigated indoor environments include dormitories, classrooms, and the library. About 30 dormitory buildings with different furniture loading ratios were measured. The characteristics of the indoor VOCs species are analyzed and possible sources are identified. The VOCs were analyzed with gas chromatography-mass spectroscopy (GC-MS). It was found that the average total VOC (TVOC) concentration can reach 2.44 mg/m(3). Alkenes were the most abundant VOCs in dormitory rooms, contributing up to 86.5% of the total VOCs concentration. The concentration of α-pinene is the highest among the alkenes. Unlike the dormitory rooms, there is almost no room with TVOC concentration above 0.6 mg/m(3) in classroom and library buildings. Formaldehyde concentration in the dormitory rooms increased about 23.7% after the installation of furniture, and the highest level reached 0.068 mg/m(3). Ammonia released from the building antifreeze material results in an average indoor concentration of 0.28 mg/m(3), which is 100% over the threshold and should be seriously considered. Further experiments were conducted to analyze the source of the α-pinene and some alkanes in dormitory rooms. The results showed that the α-pinene mainly comes from the bed boards, while the wardrobes are the main sources of alkanes. The contribution of the pinewood bed boards to the α-pinene and TVOC concentration can reach up to above 90%. The same type rooms were sampled 1 year later and the decay rate of α-pinene is quite high, close to 100%, so that it almost cannot be detected in the sampled rooms. Analysis of indoor volatile organic compounds (VOCs) in newly built campus buildings in China identified the specific constituents of indoor VOCs contaminants exposed to

  16. 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.

  17. Improvement of health risk factors after reduction of VOC concentrations in industrial and urban areas.

    Science.gov (United States)

    Lerner, Jorge Esteban Colman; Kohajda, Tibor; Aguilar, Myriam Elisabeth; Massolo, Laura Andrea; Sánchez, Erica Yanina; Porta, Atilio Andrés; Opitz, Philipp; Wichmann, Gunnar; Herbarth, Olf; Mueller, Andrea

    2014-01-01

    After reductions of fugitive and diffuse emissions by an industrial complex, a follow-up study was performed to determine the time variability of volatile organic compounds (VOCs) and the lifetime cancer risk (LCR). Passive samplers (3 M monitors) were placed outdoors (n = 179) and indoors (n = 75) in industrial, urban, and control areas for 4 weeks. Twenty-five compounds including n-alkanes, cycloalkanes, aromatics, chlorinated hydrocarbons, and terpenes were determined by GC/MS. The results show a significant decrease of all VOCs, especially in the industrial area and to a lesser extent in the urban area. The median outdoor concentration of benzene in the industrial area declined compared to the former study, around 85% and about 50% in the urban area, which in the past was strongly influenced by industrial emissions. Other carcinogenic compounds like styrene and tetrachloroethylene were reduced to approximately 60%. VOC concentrations in control areas remained nearly unchanged. According to the determined BTEX ratios and interspecies correlations, in contrast to the previous study, traffic was identified as the main emission source in the urban and control areas and showed an increased influence in the industrial area. The LCR, calculated for benzene, styrene, and tetrachloroethylene, shows a decrease of one order of magnitude in accordance to the decreased total VOC concentrations and is now acceptable according to values proposed by the World Health Organization.

  18. Environmental aspects of VOCs evolved in the early stages of human decomposition.

    Science.gov (United States)

    Statheropoulos, M; Agapiou, A; Spiliopoulou, C; Pallis, G C; Sianos, E

    2007-10-15

    In the present study, the time profile, measured as "accumulation", of volatile organic compounds (VOCs) produced during the early stages of human decomposition was investigated. A human cadaver was placed in a sealed bag at approximately the 4th day after death. Evolved VOCs were monitored for 24 h by sampling at different time intervals. VOCs produced were analyzed by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). Over 30 substances were identified in total. These included mainly aliphatic and aromatic hydrocarbons, oxygenated compounds (alcohols, aldehydes, ketones) and organic sulfides. The last were the most prominent class of compounds identified. Eleven compounds were present in all the sampling cycles and constitute a "common core": ethanol, 2-propanone, dimethyl disulfide, methyl benzene, octane, 2-butanone, methyl ethyl disulfide, dimethyl trisulfide and o-, m- and p-xylenes. The last sampling cycle yielded the most abundant compounds in number and quantities. Inorganic gases such as CO2, CO, NH3 and H2S were also determined. The fundamental physicochemical properties of the evolved VOCs were used for evaluating their environmental impacts. It appears that the decay process, which is a dynamic procedure, can provide chemical signals that might be detected and properly evaluated by experts in the fields of forensic sciences, search and rescue units and environmental scientists.

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

    Science.gov (United States)

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

    2013-09-01

    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, C6H6/Σ(methylated aromatics) and Σ(linear)/Σ(branched) alkanes ratios <1 allow to distinguish an anthropogenic source related to emissions from outlet pipes of touristic and private boats and buses.

  20. Effect of ethanol, cimetidine and propranolol on toluene metabolism in man

    DEFF Research Database (Denmark)

    Døssing, M; Bælum, Jesper; Hansen, S H

    1984-01-01

    In a climatic exposure chamber four healthy volunteers were exposed to 100ppm toluene, 100ppm toluene + ethanol, 100ppm toluene + cimetidine, and 100ppm toluene + propranolol for 7h each at random over four consecutive days. A control experiment and 3.5h of exposure to 200ppm toluene were also...... performed. Ethanol inhibited toluene metabolism by 0.5 as expressed by the urinary excretion of two of the metabolites of toluene, namely o-cresol and hippuric acid. In agreement with this, the mean alveolar concentration of toluene was greater by 1.7 during ethanol exposure; 45 min after discontinuation...... of exposure the increase was by 3.3. Neither cimetidine nor propranolol changed toluene metabolism significantly. The results indicate that ethanol may prolong the time interval in which toluene is retained in the human body in persons simultaneously exposed to ethanol and toluene. When using o...

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

    Directory of Open Access Journals (Sweden)

    T. M. Ruuskanen

    2010-09-01

    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 nmol C 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.

  2. An in-source stretched membrane inlet for on-line analysis of VOCs in water with single photon ionization TOFMS.

    Science.gov (United States)

    Hou, Keyong; Li, Fanglong; Chen, Wendong; Chen, Ping; Xie, Yuanyuan; Zhao, Wuduo; Hua, Lei; Pei, Kemei; Li, Haiyang

    2013-10-07

    An in-source, stretched, hollow fiber membrane (HFM) inlet has been developed to improve the sensitivity of on-line time-of-flight mass spectrometry (TOFMS) with a vacuum ultraviolet (VUV) lamp based single photon ionization (SPI) source for the direct analysis of liquid samples. A 2-cm HFM was stretched to 8 cm in length, and placed in the ion source and directly under the VUV lamp window with a distance of 15 mm. Compared with the conventional flow-through configuration under the same experimental conditions, the signal intensities of selected volatile organic compounds (VOCs) of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), benzene, toluene and p-xylene were increased over 5-fold in magnitude, and the response time was shortened to one-third. The limits of detection (LOD) of MTBE, ETBE, benzene, toluene and p-xylene ranged from 0.25 to 1.3 μg L(-1) with a measurement time of 60 s, and three orders of linear range were obtained with correlation coefficients of 0.9972-0.9992. The present results suggest that the in-source stretched HFM is a simple and effective way to increase the sensitivity and shorten response time of the membrane inlet, and we believe that it will also be beneficial to other types of on-line mass spectrometer for the on-line analysis of VOCs in water with a VUV lamp based SPI ion source.

  3. Hepatotoxic potential of combined toluene-chronic ethanol exposure

    Energy Technology Data Exchange (ETDEWEB)

    Howell, S.R.; Christian, J.E.; Isom, G.E.

    1986-05-01

    The hepatoxic properties of concurrent chronic oral ethanol ingestion and acute toluene inhalation were evaluated. Male rats were maintained on ethanol-containing or control liquid diets for 29 days. Animals of each group were subjected to five 20-min exposures to 10 000 ppm toluene with 30 min of room air inhalation between exposures on days 22, 24, 26, and 28 of liquid diet feeding. Some of the ethanol-fed animals were withdrawn from ethanol 14 h before exposure. Ethanol-withdrawn animals displayed an increased sensitivity to the narcotic action of toluene. Animals were sacrificed and assays performed on day 29. Stress markers (plasma corticosterone, free fatty acid, and glucose) were not affected by treatments. A modest elevation in plasma aspartate amino-transferase occurred in non-withdrawn animals receiving both ethanol and toluene. Ethanol-toluene exposure increased both relative liver weight and liver triglycerides. Toluene antagonized the hypertriglyceridemia associated with chronic ethanol ingestion. This study indicates that combined ethanol and toluene exposure has minor potential to induce acute liver injury, but results in altered deposition of hepatic triglycerides.

  4. Photocatalytic oxidation of toluene to benzaldehyde by molecular oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Y.; Bakac, A. [Ames LAb., IA (United States)]|[Iowa State Univ., Ames, IA (United States)

    1996-03-07

    The visible light irradiation of aqueous solutions containing toluene, uranyl(VI) ions, and O{sub 2} results in the formation of benzaldehyde as a major product. Small amounts of PhCH{sub 2}OH are also formed. The yields of benzaldehyde are 3 times greater for toluene-h{sub 8} than for toluene-d{sub 8}, but the kinetic isotope effect for the quenching of the excited state {sup *}UO{sub 2}{sup 2+} by toluene is negligible (k{sub toluene-h(8)}/k{sub toluene-d(8)}=1.2). This and other evidence indicate that the quenching takes place in two parallel pathways. The major one involves the aromatic portion of tolune and leads to the recovery of the reactants. The minor, productive path takes place by hydrogen atom abstraction from the methyl group, followed by the oxidation of PhCH{sub 2}{sup {center_dot}}. Cumene, benzyl alcohol, and benzaldehyde react similarly. 31 refs., 5 figs., 1 tab.

  5. The effect of toluene on oxidative processes in rat blood

    Directory of Open Access Journals (Sweden)

    SILVANA S. STAJKOVIC

    2009-01-01

    Full Text Available This study was designed to investigate the effects of toluene treatment on oxidative stress in rat blood. Since toluene metabolism produces reactive oxygen and nitrogen species, it was hypothesized that the toluene treatment would: 1 provoke changes in the activities of antioxidant enzymes, 2 impair the integrity of the cell membrane and 3 induce structural changes in the plasma proteins. Female Wistar rats were treated with toluene intraperitonally, at a daily dose of 0.38 mmol/kg body weight for 12 days, and 5 mmol/kg body weight for 6 days, respectively, with propylene glycol as the carrier. Toluene significantly increased superoxide dismutase activity at low doses, catalase activity at high doses and the level of erythrocytes malondialdehyde in both treated groups when compared to the control group. The nitrite (NO2- level in both treated groups was not different from that in the control animals. Toluene caused oxidative modification of plasma proteins and, consequently, changes in the concentration of glycoproteins and lipoproteins when compared to the control group. The observed alterations indicate that toluene treatment might be involved in free radical processes.

  6. Behavioral effects of subchronic inhalation of toluene in adult rats.

    Science.gov (United States)

    Beasley, Tracey E; Evansky, Paul A; Gilbert, Mary E; Bushnell, Philip J

    2010-01-01

    Whereas the acute neurobehavioral effects of toluene are robust and well characterized, evidence for persistent effects of repeated exposure to this industrial solvent is less compelling. The present experiment sought to determine whether subchronic inhalation of toluene caused persistent behavioral changes in rats. Adult male Long-Evans rats inhaled toluene vapor (0, 10, 100, or 1000 ppm) for 6h/day, 5 days/week for 13 weeks and were evaluated on a series of behavioral tests beginning 3 days after the end of exposure. Toluene delayed appetitively-motivated acquisition of a lever-press response, but did not affect motor activity, anxiety-related behavior in the elevated plus maze, trace fear conditioning, acquisition of an appetitively-motivated visual discrimination, or performance of a visual signal detection task. Challenges with acute inhalation of toluene vapor (1200-2400 ppm for 1 h) and injections of quinpirole (0.01-0.03 mg/kg) and raclopride (0.03-0.10 mg/kg) revealed no toluene-induced latent impairments in visual signal detection. These results are consistent with a pattern of subtle and inconsistent long-term effects of daily exposure to toluene vapor, in contrast to robust and reliable effects of acute inhalation of the solvent.

  7. Comparison between urinary o-cresol and toluene as biomarkers of toluene exposure.

    Science.gov (United States)

    Fustinoni, Silvia; Mercadante, Rosa; Campo, Laura; Scibetta, Licia; Valla, Carla; Consonni, Dario; Foà, Vito

    2007-01-01

    The characteristics of urinary o-cresol (o-C) and urinary toluene (TOL-U) as biomarkers of occupational exposure to toluene were comparatively evaluated. One hundred healthy male rotogravure printing workers and 161 male and female control subjects were studied. Personal exposure to airborne toluene (TOL-A) during the shift was determined as a time-weighted average. Simple analytical procedures based on solid phase microextraction followed by gas chromatography/mass spectometry analysis were applied to the determination of end-shift o-C and TOL-U. Median TOL-A was 48 (6.0-162.0) mg/m3 in printers and 0.021 (<0.003-0.137) mg/m3 in controls. o-C was 0.185 (0.032-0.948) mg/g creatinine in printers and 0.027 (<0.006-0.330) mg/g creatinine in the controls. TOL-U was 7.6 (1.8-23.9) microg/L in printers and 0.140 (0.094-0.593) microg/L in the controls. According to all indices, exposure to toluene was higher in printers than in the controls. Nevertheless, the distribution of o-C in the two groups partially overlapped, whereas such behavior was not found in TOL-U. Both o-C and TOL-U in printers were correlated with TOL-A (Pearson's on log10-transformed variables r = 0.704 and 0.844, respectively) and with each other (r = 0.683). Smoking habits significantly increased the excretion of o-C but not of TOL-U. From the point of view of sampling conditions and analytical requirements, TOL-U and o-C showed similar properties, but comparison of their intrinsic characteristics showed that TOL-U had higher specificity and sensitivity, lower background values, was better correlated with airborne exposure, and was not influenced by cigarette smoking. Therefore TOL-U may be considered superior to o-C as a biomarker of occupational exposure to toluene.

  8. Pollution Characteristics and Ozone Formation Potential of Ambient VOCs in Winter and Spring in Xiamen%厦门冬春季大气VOCs的污染特征及臭氧生成潜势

    Institute of Scientific and Technical Information of China (English)

    徐慧; 张晗; 邢振雨; 邓君俊

    2015-01-01

    Air samples were collected at urban and rural sites in Xiamen from January to April 2014. The concentrations of 48 ambient volatile organic compounds( VOC) species were measured by the method of cryogenic pre-concentrator and gas chromatography-mass spectrometry(GC/MS). The ozone formation potential(OFP) of VOCs was also calculated with the method of maximum incremental reactivity( MIR) . The results showed that the average mixing ratios of VOCs in winter were 11. 13 × 10 -9 and 7. 17 × 10 -9 at urban and rural sites, respectively, and those in spring were 24. 88 × 10 -9 and 11. 27 × 10 -9 at urban and rural sites, respectively. At both sites, alkanes contributed the most to VOCs, followed by aromatics and alkenes. The ratios of B/T showed that vehicle and solvent evaporation were the main sources of VOCs at urban site. While at rural site, transport of anthropogenic sources was another important source of VOCs besides local biomass emissions. Ten main components including propene, n-butane, i-butane, n-pentane, i-pentane, n-hexane, benzene, toluene, ethylbenzene and m/p-xylene accounted for 61. 57% and 45. 83% of total VOCs at urban and rural sites in winter, respectively, and 62. 83% and 53. 74% at urban and rural sites in spring, respectively. Aromatics contributed the most to total OFP, followed by alkenes. Alkanes contributed the least to OFP with the highest concentration. C3 , C4 alkenes and aromatics were found to be the more reactive species with relatively high contributions to ozone formation in Xiamen. Comparing the average MIR of VOCs at the two sites, it was found that the reactivity of VOCs at rural site was higher than that at urban site.%2014年1~4月在厦门市城区和郊区开展冬春季节大气样品的采集,采用大气预浓缩系统与GC/MS联用技术定量了48种大气挥发性有机物( VOCs),对比分析了冬春季城区和郊区大气VOCs的污染特征,并利用最大增量反应活性( MIR)估算

  9. Toluene alters p75NTR expression in the rat brainstem.

    Science.gov (United States)

    Pascual, Jesús; Morón, Lena; Zárate, Jon; Gutiérrez, Arantza; Churruca, Itziar; Echevarría, Enrique

    2004-01-01

    Toluene is a neurotoxic organic solvent widely used in industry. Acute toluene administration in rats induced a significant increase in the numbers of neural cells immunostained for p75NTR in several brainstem regions, such as the raphe magnus and the nucleus of the solitary tract, as well as in the lateral reticular, gigantocellular, vestibular and ventral cochlear nuclei, without any in the facial and spinal trigeminal nuclei and the dorsal horn of the spinal cord. These data suggest that p75NTR could be involved in toluene-induced neurotoxic efffects in the rat brainstem.

  10. Interactions between Asphaltenes and Water in Solutions in Toluene

    DEFF Research Database (Denmark)

    Khvostichenko, Daria; Andersen, Simon Ivar

    2008-01-01

    Binding of water by asphaltenes dissolved in toluene was investigated for two asphaltene samples, OMV1 and OMV2, from the same reservoir deposit. Solubility of water in asphaltene solutions in toluene was found to increase with an increasing asphaltene concentration, indicative of solubilization...... was determined for water-saturated solutions (OMV1 and OMV2) and for water-unsaturated solutions (OMV1 only). These numbers were found to decrease from several water molecules per asphaltene molecule to below unity upon an increase of the asphaltene concentration in toluene from 0.1 to 20 g/L, suggesting...

  11. 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.

  12. Expression of Xhdsi-1VOC, a novel member of the vicinal oxygen chelate (VOC) metalloenzyme superfamily, is up-regulated in leaves and roots during desiccation in the resurrection plant Xerophyta humilis (Bak) Dur and Schinz

    Science.gov (United States)

    Mulako, I.; Farrant, J. M.; Collett, H.; Illing, N.

    2008-01-01

    The annotation of novel plant genes is frequently based on sequence and structural similarity to known protein motifs. Understanding the biological function of these genes is dependent on identifying conditions under which they are activated, however. The resurrection plant, Xerophyta humilis is a good model system for identifying and characterizing genes which are important for desiccation tolerance. Desiccation induced-1 (dsi-1VOC), a previously uncharacterized plant gene, is up-regulated during desiccation in leaves, roots, and seeds in X. humilis. The X. humilis desiccation induced-1 gene, Xhdsi-1VOC, shares structural homology with the vicinal oxygen chelate (VOC) metalloenzyme superfamily. Proteins in this superfamily share little sequence similarity, but are characterized by a common βαβββ structural fold. A number of plant orthologues of XhDsi-1VOC have been identified, including Arabidopsis thaliana At1g07645, which is currently annotated as a glyoxalase I-like gene, and many ESTs derived from seed cDNA libraries. Xhdsi-1VOC and its orthologues do not, however, contain the glutathione and zinc binding sites conserved in glyoxalase I genes. Furthermore, expression of Xhdsi-1VOC in yeast failed to rescue a yeast glyoxalase I mutant. Messenger RNA transcripts for At1g07645 accumulate during seed maturation, but are not induced by water loss, salt or mannitol stress in vegetative tissue in Arabidopsis. It is concluded that dsi-1VOC is a seed-specific gene in desiccation-sensitive plants that is activated by water loss in vegetative tissues in the resurrection plant X. humilis and plays an important role in allowing plant tissues to survive loss of 95% of their relative water content. PMID:18791196

  13. 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.

  14. The effect of cold trap adsorbents on the gas chromatographic analysis of ambient VOCs under Peltier cooling conditions.

    Science.gov (United States)

    Pal, Raktim; Kim, Ki-Hyun

    2008-04-01

    In this work, the relative analytical performance of the GC-based detection method was investigated with a major focus on cold trap (CT) adsorbent materials against four aromatic volatile organic compounds (VOCs) (e. g., benzene, toluene, xylene, and styrene). A series of calibration experiments were hence conducted under cryofocusing conditions formed by the Peltier cooling system in a thermal desorber (TD) unit. During the course of this study, comparative calibration datasets were acquired for each of the three CT types: (i) CT (I) = Carbopack B + Carbopack C, (ii) CT (II) = Carbopack B + Carboxen 1000, and (iii) CT (III) = Tenax TA. All calibration datasets were obtained under subambient temperature (-10 degrees C) conditions controlled by the Peltier cooling system. The reliability of the calibration data was also assessed in an ancillary experiment with the aid of the modified injection through a thermal desorber (MITD) method. The results demonstrated that the GC detection properties of different VOCs were not altered significantly between different CT applications under Peltier conditions, although relative sensitivity could be distinguished moderately depending on the CT type.

  15. Preparation of hierarchical layer-stacking Mn-Ce composite oxide for catalytic total oxidation of VOCs

    Institute of Scientific and Technical Information of China (English)

    唐文翔; 武晓峰; 刘刚; 李双德; 李东艳; 李文辉; 陈运法

    2015-01-01

    Hierarchical layer-stacking Mn-Ce composite oxide with mesoporous structure was firstly prepared by a simple precipita-tion/decomposition procedure with oxalate precursor and the complete catalytic oxidation of VOCs (benzene, toluene and ethyl ace-tate) were examined. The Mn-Ce oxalate precursor was obtained from metal salt and oxalic acid without any additives. The resulting materials were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), en-ergy dispersive X-ray spectroscopy (EDX), hydrogen temperature programmed reduction (H2-TPR) and X-ray photoelectron spec-troscopy (XPS). Compared with Mn-Ce composite oxide synthesized through a traditional method (Na2CO3 route), the hierarchical layer-stacking Mn-Ce composite oxide exhibited higher catalytic activity in the complete oxidation of volatile organic compounds (VOCs). By means of testing, the data revealed that the hierarchical layer-stacking Mn-Ce composite oxide possessed superior physiochemical properties such as good low-temperature reducibility, high manganese oxidation state and rich adsorbed surface oxy-gen species which resulted in the enhancement of catalytic abilities.

  16. In vitro Characterization of Phenylacetate Decarboxylase, a Novel Enzyme Catalyzing Toluene Biosynthesis in an Anaerobic Microbial Community.

    Science.gov (United States)

    Zargar, K; Saville, R; Phelan, R M; Tringe, S G; Petzold, C J; Keasling, J D; Beller, H R

    2016-08-10

    Anaerobic bacterial biosynthesis of toluene from phenylacetate was reported more than two decades ago, but the biochemistry underlying this novel metabolism has never been elucidated. Here we report results of in vitro characterization studies of a novel phenylacetate decarboxylase from an anaerobic, sewage-derived enrichment culture that quantitatively produces toluene from phenylacetate; complementary metagenomic and metaproteomic analyses are also presented. Among the noteworthy findings is that this enzyme is not the well-characterized clostridial p-hydroxyphenylacetate decarboxylase (CsdBC). However, the toluene synthase under study appears to be able to catalyze both phenylacetate and p-hydroxyphenylacetate decarboxylation. Observations suggesting that phenylacetate and p-hydroxyphenylacetate decarboxylation in complex cell-free extracts were catalyzed by the same enzyme include the following: (i) the specific activity for both substrates was comparable in cell-free extracts, (ii) the two activities displayed identical behavior during chromatographic separation of cell-free extracts, (iii) both activities were irreversibly inactivated upon exposure to O2, and (iv) both activities were similarly inhibited by an amide analog of p-hydroxyphenylacetate. Based upon these and other data, we hypothesize that the toluene synthase reaction involves a glycyl radical decarboxylase. This first-time study of the phenylacetate decarboxylase reaction constitutes an important step in understanding and ultimately harnessing it for making bio-based toluene.

  17. Co-formation of hydroperoxides and ultra-fine particles during the reactions of ozone with a complex VOC mixture under simulated indoor conditions

    DEFF Research Database (Denmark)

    Fan, Z.H.; Weschler, Charles J.; Han, IK

    2005-01-01

    in the O-3/23 VOCs system. The present study confirmed the findings of a previous study carried out in a real-world office and generated new findings regarding co-formation of UFP. Through a comparative analysis of H2O2* yields under different reaction conditions, this study demonstrates that VOCs co......) under simulated indoor conditions. The VOC mixture contained 23 compounds, including two terpenes (d-limonene and alpha-pinene), two unsaturated alkenes (1-decene and 1-octene), and 19 other saturated organic compounds. These compounds are commonly found in indoor air but their concentrations were...

  18. A novel method to quantify the emission and conversion of VOCs in the smoking of electronic cigarettes

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-11-01

    An analytical technique was developed for the quantitation of volatile organic compounds (VOC) in three different forms of electronic cigarette (EC): solution, vapor, and aerosol. Through the application of the mass change tracking (MCT) approach, the consumed amount of the solution was measured to track the conversion of targets between the different phases. The concentration of aerosol plus vapor (A&V) decreased exponentially (559 to 129 g m-3) with increasing puff velocity (0.05 to 1 L min-1). A strong correlation existed between sampling volume and consumed solution mass (R2 = 0.9972 ± 0.0021 (n = 4)). In the EC solution, acetic acid was considerably high (25.8 μg mL-1), along with trace quantities of some VOCs (methyl ethyl ketone, toluene, propionic acid, and i-butyric acid: 0.24 ± 0.15 μg mL-1 (n = 4)). In the aerosol samples, many VOCs (n-butyraldehyde, n-butyl acetate, benzene, xylene, styrene, n-valeric acid, and n-hexanoic acid) were newly produced (138 ± 250 μg m-3). In general, the solution-to-aerosol (S/A) conversion was significant: e.g., 1,540% for i-butyric acid. The emission rates of all targets computed based on their mass in aerosol/ consumed solution (ng mL-1) were from 30.1 (p-xylene) to 398 (methyl ethyl ketone), while those of carboxyls were much higher from 166 (acetic acid) to 5,850 (i-butyric acid).

  19. Selectivity of Chemoresistive Sensors Made of Chemically Functionalized Carbon Nanotube Random Networks for Volatile Organic Compounds (VOC

    Directory of Open Access Journals (Sweden)

    Jean-François Feller

    2014-01-01

    Full Text Available Different grades of chemically functionalized carbon nanotubes (CNT have been processed by spraying layer-by-layer (sLbL to obtain an array of chemoresistive transducers for volatile organic compound (VOC detection. The sLbL process led to random networks of CNT less conductive, but more sensitive to vapors than filtration under vacuum (bucky papers. Shorter CNT were also found to be more sensitive due to the less entangled and more easily disconnectable conducting networks they are making. Chemical functionalization of the CNT’ surface is changing their selectivity towards VOC, which makes it possible to easily discriminate methanol, chloroform and tetrahydrofuran (THF from toluene vapors after the assembly of CNT transducers into an array to make an e-nose. Interestingly, the amplitude of the CNT transducers’ responses can be enhanced by a factor of five (methanol to 100 (chloroform by dispersing them into a polymer matrix, such as poly(styrene (PS, poly(carbonate (PC or poly(methyl methacrylate (PMMA. COOH functionalization of CNT was found to penalize their dispersion in polymers and to decrease the sensors’ sensitivity. The resulting conductive polymer nanocomposites (CPCs not only allow for a more easy tuning of the sensors’ selectivity by changing the chemical nature of the matrix, but they also allow them to adjust their sensitivity by changing the average gap between CNT (acting on quantum tunneling in the CNT network. Quantum resistive sensors (QRSs appear promising for environmental monitoring and anticipated disease diagnostics that are both based on VOC analysis.

  20. ADVANCES ON THE RESEARCH AND DEVELOPMENT OF CATALYSTS FOR TOLUENE DISPROPORTIONATION AND C9 AROMATICS TRANSALKYLATION

    Institute of Scientific and Technical Information of China (English)

    Chen Qingling; Xie Zaiku

    2001-01-01

    Advances on the development of commercial catalysts using in the processes such as Tatoray(Toluene Disproportionation and C9 Aromatics Transalkylation of UOP Company), MTDP (Toluene Disproportionation Process of Mobil Company), S-TDT (Toluene Disproportionation and C9 Aromatics Transalkylation of SRIPT), Trans-Plus, PX-Plus (Selective Toluene Disproportionation of UOP Company) and MSTDP (Selective Toluene Disproportionation Process on Mobils ZSM-5 catalyst) have been reviewed. The trends on the research of the new catalysts such as ZSM-5,Beta, MCM-22, Omega, SAPO and modified Y for the selective toluene disproportionation process and for the toluene disproportionation and C9 aromatics transalkylation have been described.

  1. 78 FR 37818 - Request for Information on Toluene Diisocyanates

    Science.gov (United States)

    2013-06-24

    ... published a Current Intelligence Bulletin on toluene diisocyanate (TDI) and toluenediamine (TDA) [DHHS (NIOSH) Publication No. 90-101] which classified TDI and TDA (used in the manufacturing of TDI)...

  2. Alkylation of toluene with isopropyl alcohol over SAPO-5 catalyst

    Indian Academy of Sciences (India)

    Sreedevi Upadhyayula

    2009-03-01

    Isopropylation of toluene with isopropyl alcohol was studied over the large pore silicon alumino phosphate molecular sieves (SAPO-5) with varying Si content. Toluene conversion was found to increase with increase in the Si of the catalysts. The effect of temperature on yields of cymene was studied in the range of 453 to 553 K. The highest yield and selectivity for cymene was observed at 513 K. Good cymene selectivity was confirmed with the absence of -propyl toluene in the product. The catalyst activity, in terms of -cymene selectivity, remained almost stable during a nine hour time on stream run. Enhanced cymene selectivity and decreased -cymene selectivity was observed with increase in the toluene to isopropyl alcohol feed mole ratio from 2 to 8. Power law model and L-H-H-W model fitted the experimental data well and are used to explain the kinetics of this reaction.

  3. Microbial abatement of toluene using Aspergillus niger in upflow bioreactor.

    Science.gov (United States)

    Gopinath, M; Mohanapriya, C; Sivakumar, K; Baskar, G; Muthukumaran, C; Dhanasekar, R

    2016-12-01

    Microbial abatement of toluene using Aspergillus niger in coir packed upflow bioreactor was investigated in this study. Toluene degrading microbes were isolated from municipal sewage effluent and identified by 16s rRNA sequencing method. The microbes were cultured in 2% (v/v) toluene input per day, which exhibited 95% removal efficiency with the kinetic correction value (R(2)) of 0.9024 at the optimum flow rate of about 0.4m(3)h(-1). Various parameters such as effect of flow rate, column height, elimination capacity and EBRT with removal efficiency for 50 day cycle were also optimized. The plug flow model for toluene degradation was properly expressed and the Monod kinetics constant Km and rmax values were determined as 2.25gm(-3) and 67.773gm(-3)h(-1) respectively for microbial growth rate. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. 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.

  5. Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

    Science.gov (United States)

    Song, Mijung; Liu, Pengfei F.; Hanna, Sarah J.; Zaveri, Rahul A.; Potter, Katie; You, Yuan; Martin, Scot T.; Bertram, Allan K.

    2016-07-01

    To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α-pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295 ± 1 K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10-1 to ˜ 6 × 106 Pa s from 30 to 90 % RH, and greater than ˜ 2 × 108 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17 %. These viscosities correspond to Stokes-Einstein-equivalent diffusion coefficients for large organic molecules of ˜ 2 × 10-15 cm2 s-1 for 30 % RH, and lower than ˜ 3 × 10-17 cm2 s-1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1-5 h for 30 % RH, and higher than ˜ 100 h for RH ≤ 17 %. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be well-mixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long and the particles may not be well-mixed in the afternoon (15:00-17:00 LT) during certain times of the

  6. THE ADSORPTION BEHAVIORS OF TOLUENE ON HYPERCROSSLINKED RESINS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Investigation of the adsorption characteristics of toluene on two hypercrosslinked resins. The static and the kinetic adsorption were studied. The equilibrium adsorption date was fitted to freundlich adsorption isotherm models to evaluate the model parameters. The enthalpy, free energy, entropy are indicative of an exothermic, a spontaneous and disorter decreasing process. Experimental results show that the two adsorbents are better than the Amberlite XAD-4 for removingthe toluene in aqueous solutions.

  7. Metabolism of Benzene, Toluene, and Xylene Hydrocarbons in Soil†

    OpenAIRE

    Tsao, C.-W.; Song, H. -G.; Bartha, R

    1998-01-01

    Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the produ...

  8. Toluene-induced hearing loss in acivicin-treated rats.

    Science.gov (United States)

    Waniusiow, Delphine; Campo, Pierre; Cossec, Benoît; Cosnier, Frédéric; Grossman, Stephane; Ferrari, Luc

    2008-01-01

    Toluene can be considered an ototoxic chemical compound in the rat. Outer hair cells are particularly sensitive to this aromatic organic solvent or to one of its metabolites. The objective of the present study was to evaluate the possible role played by cysteine S-conjugates in the ototoxic process in Long-Evans rats. To this end, renal and hepatic metabolism of toluene was modified by treatment with acivicin, an inhibitor of gamma-glutamyl transferase (gamma-GT). First, the efficacy of the acivicin treatment was established from a dose-response investigation in which urinary gamma-GT was measured daily in rats exposed to 1750 ppm toluene, 6 h per day for five days. A twice weekly 5 mg/kg dose was reduced urinary gamma-GT by 70-78%. In a subacute experiment, rats were exposed to 1750 ppm toluene for four consecutive weeks, in which the efficacy of the acivicin treatment was monitored by quantifying the urinary end product of the conjugate pathway: benzyl mercapturic acid (BMA). A 38.5% decrease in BMA was measured at the end of the exposure period. Hearing impairment was evaluated using auditory (inferior colliculus) evoked potentials and completed with conventional histological approaches. The toluene-exposed and the acivicin-treated rats exposed to toluene both had a 7-dB permanent auditory threshold shift at 16-20 kHz. Hair cell loss was not dependent on acivicin treatment. Therefore, the partial inhibition of gamma-GT did not modify the toluene ototoxicity, suggesting that toluene-induced hearing loss is not strongly mediated by the production of cysteine S-conjugates. However, the data do not rule out the possibility that these metabolites may play a minor role.

  9. A membrane bioreactor for the removal of dimethyl sulphide and toluene from waste air.

    Science.gov (United States)

    Van Langenhove, H; De Bo, I; Jacobs, P; Demeestere, K; Dewulf, J

    2004-01-01

    In biotrickling filters, mass transfer of hydrophobic compounds is the limiting factor. Biofilters are static systems, and so control and regulation of operational parameters such as pH and nutrient supply can be a problem. In membrane bioreactors, these drawbacks can be avoided. The hydrophobic membrane separates the waste air from the aqueous phase, thus avoiding mass-transfer limitation, while pH and nutrient supply can be directly controlled. In this contribution, an overview will be given of results obtained during a four-year project. First, the physical chemical characteristics (solubility, permeability, diffusivity) and microbial adhesion of different membranes were tested. This led to the selection of a composite membrane consisting of a porous polyvinylidenefluoride (PVDF) support layer coated with a thin (1 or 2.5 microm) dense polydimethylsiloxane (PDMS) top layer. This membrane was mounted into a module provided with four parallel rectangular channels for gas flow (in contact with the porous layer) and nutrient solution (in contact with the dense layer) respectively. After inoculation, a biofilm developed on the dense layer. Experiments were performed with dimethyl sulphide and toluene as target VOCs. Operational characteristics such as elimination capacity as a function of the volumetric load and residence time, effect of nutrient supply, long-term performance) were determined. Mass transfer was studied by measuring concentration profiles along the channels of the module in different conditions.

  10. 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.

  11. 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

  12. Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO{sub 2}) in a medium size city in Northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Parra, M.A. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra. Irunlarrea 1, 31008, Pamplona, Navarra (Spain)], E-mail: mparravi@alumni.unav.es; Elustondo, D.; Bermejo, R.; Santamaria, J.M. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra. Irunlarrea 1, 31008, Pamplona, Navarra (Spain)

    2009-01-15

    Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO{sub 2}) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO{sub 2} samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO{sub 2} were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 {mu}g m{sup -3} respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO{sub 2} occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO{sub 2} exceeded the European limits at some of the monitored points.

  13. Synthesis of Toluene-2,4-Bisurea from 2,4-Toluene Diamine and Urea and the Reaction Kinetics

    Institute of Scientific and Technical Information of China (English)

    王娜; 耿艳楼; 安华良; 赵新强; 王延吉

    2013-01-01

    Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance. Firstly, thermodynamic analysis shows that the reaction is exothermic and a high equilibrium conversion of TDA is expected due to its large reaction equilibrium constant. Secondly, under the suitable reaction conditions, 130 °C, 7 h, and molar ratio of TDA/zinc acetate/urea/sulfolane=1/0.05/3.5/10, TDA conversion is 54.3%, and TBU yield and selectivity are 39.8%and 73.3%respectively. Lastly, the synthesis of TBU is a 1st order reaction with respect to TDA and the reaction kinetics model is established. This work will provide useful information for commercializing the urea route to toluene-2,4-dicarbamate (TDC).

  14. Striatal dopamine dynamics in mice following acute and repeated toluene exposure.

    Science.gov (United States)

    Apawu, Aaron K; Mathews, Tiffany A; Bowen, Scott E

    2015-01-01

    The abused inhalant toluene has potent behavioral effects, but only recently has progress been made in understanding the neurochemical actions that mediate the action of toluene in the brain. Available evidence suggests that toluene inhalation alters dopamine (DA) neurotransmission, but toluene's mechanism of action is unknown. The present study evaluated the effect of acute and repeated toluene inhalation (0, 2,000, or 4,000 ppm) on locomotor activity as well as striatal DA release and uptake using slice fast-scan cyclic voltammetry. Acutely, 2,000 and 4,000 ppm toluene increased locomotor activity, while neurochemically only 4,000 ppm toluene potentiated electrically evoked DA release across the caudate-putamen and the nucleus accumbens. Repeated administration of toluene resulted in sensitization to toluene's locomotor activity effects. Brain slices obtained from mice repeatedly exposed to toluene demonstrated no difference in stimulated DA release in the caudate-putamen as compared to control animals. Repeated exposure to 2,000 and 4,000 ppm toluene caused a concentration-dependent decrease of 25-50 % in evoked DA release in the nucleus accumbens core and shell relative to air-exposed mice. These voltammetric neurochemical findings following repeated toluene exposure suggest that there may be a compensatory downregulation of the DA system. Acute or repeated toluene exposure had no effect on the DA uptake kinetics. Taken together, these results demonstrate that acute toluene inhalation potentiates DA release, while repeated toluene exposure attenuates DA release in the nucleus accumbens only.

  15. Catalytic activity of zeolites in the formation of cresols from phenol and toluene

    Energy Technology Data Exchange (ETDEWEB)

    Kozhevnikov, S.A.; Sibarov, D.A.; Proskuryakov, V.A.

    1988-06-10

    This paper explores a synthetic method of obtaining cresols from phenol and toluene in order to replace coal tar with more abundant chemicals as raw materials for cresol synthesis. The method consists of the transmethylation of phenol with toluene under the action of zeolite catalysts. The zeolites tested include NaY, MgCaY, MnCaY, LiCaY, NiCaY, CrCaY, CaHY, and LaCaHY. Direct dependence of the activity of zeolite catalysts in transmethylation on the strength of the surface acidic centers was observed. Increased substitution of Ca divalent cations by La divalent cations promoted high activity and selectivity of the catalyst in formation of cresols.

  16. Volumetric properties under pressure for the binary system ethanol plus toluene

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Lugo, Luis; García, Josefa

    2005-01-01

    The density of the asymmetrical binary system composed of ethanol and toluene has been measured under pressure using a vibrating tube densimeter. The measurements have been performed for nine different compositions including the pure compounds at eight temperatures in the range 283.15–353.15 K....... At several temperatures the isobaric thermal expansion shows an non-monotonical behavior versus composition, whereas the excess molar volumes reveal a complex sigmoid behavior. These results have been interpreted as changes in the free-volume and as the formation and weakening of the molecular interactions....... The VLE behavior of this binary system within the considered temperature range is represented satisfactory by the perturbed-chain statistical association fluid theory (PC-SAFT) equation of state with a single interaction parameter, although no cross association between ethanol and toluene is taken...

  17. Modelling of toluene biodegradation and biofilm growth in a fixed biofilm reactor

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1992-01-01

    The modelling of aerobic biodegradation of toluene and the associated biofilm growth in a fixed biofilm system is presented. The model includes four biomass fractions, three dissolved components, and seven processes. It is assumed that part of the active biomass is composed of filamentous bacteria...... which grow relatively fast and detach easily, leading to a biomass growth delayed with respect to substrate degradation. The non-filamentous bacteria inside the biofilm also degrade toluene but with a slower rate compared to the filamentous bacteria. Because the nonfilamentous bacteria do not detach......, they are primarily responsible for the biofilm growth. The active biomass decays into biodegradable and ``inert'' dead biomass which is hydrolyzed into soluble products at two different rates. These products are partly degradable by the biomass and constitute the endogenous respiration. The dynamic growth phase...

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

    Science.gov (United States)

    Baudic, Alexia; Gros, Valérie; Sauvage, Stéphane; Locoge, Nadine; Sanchez, Olivier; Sarda-Estève, Roland; Kalogridis, Cerise; Petit, Jean-Eudes; Bonnaire, Nicolas; Baisnée, Dominique; Favez, Olivier; Albinet, Alexandre; Sciare, Jean; Bonsang, Bernard

    2016-09-01

    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 important finding of

  19. Chemical kinetic study of the oxidation of toluene and related cyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mehl, M; Frassoldati, A; Fietzek, R; Faravelli, T; Pitz, W; Ranzi, E

    2009-10-01

    Chemical kinetic models of hydrocarbons found in transportation fuels are needed to simulate combustion in engines and to improve engine performance. The study of the combustion of practical fuels, however, has to deal with their complex compositions, which generally involve hundreds of compounds. To provide a simplified approach for practical fuels, surrogate fuels including few relevant components are used instead of including all components. Among those components, toluene, the simplest of the alkyl benzenes, is one of the most prevalent aromatic compounds in gasoline in the U.S. (up to 30%) and is a promising candidate for formulating gasoline surrogates. Unfortunately, even though the combustion of aromatics been studied for a long time, the oxidation processes relevant to this class of compounds are still matter of discussion. In this work, the combustion of toluene is systematically approached through the analysis of the kinetics of some important intermediates contained in its kinetic submechanism. After discussing the combustion chemistry of cyclopentadiene, benzene, phenol and, finally, of toluene, the model is validated against literature experimental data over a wide range of operating conditions.

  20. Use of Compound Specific Stable Isotope Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs

    Science.gov (United States)

    2012-01-01

    chlorinated hydrocarbons . The full list of the compounds included (weight %): ethanol – 69 % n-decane – 4 % p-xylene – 9 % MEK – 10 % n-pentane – 5...biodegradation of trichloroethylene and toluene: Implications for intrinsic bioremediation . Organic Geochem. 1999, 30, 813-820. 9) SIGMA-ALDRICH

  1. A Novel Methodology to Evaluate Health Impacts Caused by VOC Exposures Using Real-Time VOC and Holter Monitors

    Directory of Open Access Journals (Sweden)

    Hiroaki Kumano

    2010-11-01

    Full Text Available While various volatile organic compounds (VOCs are known to show neurotoxic effects, the detailed mechanisms of the action of VOCs on the autonomic nervous system are not fully understood, partially because objective and quantitative measures to indicate neural abnormalities are still under development. Nevertheless, heart rate variability (HRV has been recently proposed as an indicative measure of the autonomic effects. In this study, we used HRV as an indicative measure of the autonomic effrects to relate their values to the personal concentrations of VOCs measured by a real-time VOC monitor. The measurements were conducted for 24 hours on seven healthy subjects under usual daily life conditions. The results showed HF powers were significantly decreased for six subjects when the changes of total volatile organic compound (TVOC concentrations were large, indicating a suppression of parasympathetic nervous activity induced by the exposure to VOCs. The present study indicated these real-time monitoring was useful to characterize the trends of VOC exposures and their effects on autonomic nervous system.

  2. Toluene removal from waste air stream by the catalytic ozonation process with MgO/GAC composite as catalyst.

    Science.gov (United States)

    Rezaei, Fatemeh; Moussavi, Gholamreza; Bakhtiari, Alireza Riyahi; Yamini, Yadollah

    2016-04-05

    This paper investigates the catalytic potential of MgO/GAC composite for toluene elimination from waste air in the catalytic ozonation process (COP). The MgO/GAC composite was a micro-porous material with the BET surface area of 1082m(2)/g. Different functional groups including aromatic CC, saturated CO of anhydrates, hydroxyl groups and SH bond of thiols were identified on the surface of MgO/GAC. Effects of residence time (0.5-4s), inlet toluene concentration (100-400ppmv) and bed temperature (25-100°C) were investigated on degradation of toluene in COP. Impregnation of GAC with MgO increased the breakthrough time and removal capacity by 73.9% and 64.6%, respectively, at the optimal conditions. The catalytic potential of the GAC and MgO/GAC for toluene degradation was 11.1% and 90.6%, respectively, at the optimum condition. The highest removal capacity using MgO/GAC (297.9gtoulene/gMgO/GAC) was attained at 100°C, whereas the highest removal capacity of GAC (128.5mgtoulene/gGAC) was obtained at 25°C. Major by-products of the toluene removal in COP with GAC were Formic acid, benzaldehyde, O-nitro-p-cresol and methyl di-phenyl-methane. MgO/GAC could greatly catalyze the decomposition of toluene in COPand formic acid was the main compound desorbed from the catalyst. Accordingly, the MgO/GAC is an efficient material to catalyze the ozonation of hydrocarbon vapors.

  3. Performance of the JULES land surface model for UK Biogenic VOC emissions

    Science.gov (United States)

    Hayman, Garry; Comyn-Platt, Edward; Vieno, Massimo; Langford, Ben

    2017-04-01

    Emissions of biogenic non-methane volatile organic compounds (NMVOCs) are important for air quality and tropospheric composition. Through their contribution to the production of tropospheric ozone and secondary organic aerosol (SOA), biogenic VOCs indirectly contribute to climate forcing and climate feedbacks [1]. Biogenic VOCs encompass a wide range of compounds and are produced by plants for growth, development, reproduction, defence and communication [2]. There are both biological and physico-chemical controls on emissions [3]. Only a few of the many biogenic VOCs are of wider interest and only two or three (isoprene and the monoterpenes, α- and β-pinene) are represented in chemical transport models. We use the Joint UK Land Environment Simulator (JULES), the UK community land surface model, to estimate biogenic VOC emission fluxes. JULES is a process-based model that describes the water, energy and carbon balances and includes temperature, moisture and carbon stores [4, 5]. JULES currently provides emission fluxes of the 4 largest groups of biogenic VOCs: isoprene, terpenes, methanol and acetone. The JULES isoprene scheme uses gross primary productivity (GPP), leaf internal carbon and the leaf temperature as a proxy for the electron requirement for isoprene synthesis [6]. In this study, we compare JULES biogenic VOC emission estimates of isoprene and terepenes with (a) flux measurements made at selected sites in the UK and Europe and (b) gridded estimates for the UK from the EMEP/EMEP4UK atmospheric chemical transport model [7, 8], using site-specific or EMEP4UK driving meteorological data, respectively. We compare the UK-scale emission estimates with literature estimates. We generally find good agreement in the comparisons but the estimates are sensitive to the choice of the base or reference emission potentials. References (1) Unger, 2014: Geophys. Res. Lett., 41, 8563, doi:10.1002/2014GL061616; (2) Laothawornkitkul et al., 2009: New Phytol., 183, 27, doi

  4. New observations of VOC emissions and concentrations in, above, and around the Central Valley of California

    Science.gov (United States)

    Goldstein, A. H.; Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Ormeno, E.; Holzinger, R.; Misztal, P. K.; Karl, T. R.; Guenther, A. B.; Fischer, M. L.; Harley, R. A.; Karlik, J. F.

    2011-12-01

    in-situ GC included more than 200 anthropogenic and biogenic VOCs with a wide range of volatilities (up to 17 carbon atoms in size) and various functional groups (e.g. aldehydes, ketones, alcohols, halogens, sulfur, & nitrogen). Finally, in 2011 vertical profiles of VOC were made at 5 heights on a communication tower at Walnut Grove (~20 miles south of Sacramento) from 30' to 1550' by PTRMS. Results from all of these studies combined provide a novel overview of the distribution of VOC emissions and concentrations in, around, and above the Central Valley of California.

  5. 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.

  6. Evaluation of simultaneous biodegradation of methane and toluene in landfill covers.

    Science.gov (United States)

    Su, Yao; Zhang, Xuan; Wei, Xiao-Meng; Kong, Jiao-Yan; Xia, Fang-Fang; Li, Wei; He, Ruo

    2014-06-15

    The biodegradation of CH4 and toluene in landfill cover soil (LCS) and waste biocover soil (WBS) was investigated with a serial toluene concentration in the headspace of landfill cover microcosms in this study. Compared with the LCS sample, the higher CH4 oxidation activity and toluene-degrading capacity occurred in the WBS sample. The co-existence of toluene in landfill gas would positively or negatively affect CH4 oxidation, mainly depending on the toluene concentrations and exposure time. The nearly complete inhibition of toluene on CH4 oxidation was observed in the WBS sample at the toluene concentration of ∼ 80,000 mg m(-3), which was about 10 times higher than that in the LCS sample. The toluene degradation rates in both landfill covers fitted well with the Michaelis-Menten model. These findings showed that WBS was a good alternative landfill cover material to simultaneously mitigate emissions of CH4 and toluene from landfills to the atmosphere.

  7. 生物过滤床处理甲苯和乙酸乙酯混合废气%SIMULTANEOUS BIOFILTRATION OF ETHYL ACETATE AND TOLUENE IN EMISSION GAS

    Institute of Scientific and Technical Information of China (English)

    刘永慧; 孙玉梅; 全燮; 陈景文; 薛大明; 张晓飞

    2002-01-01

    Two biofilters,RA which had been exposed to varying concentration of ethyl acetate for 20 days and RB which had been exposed to varying concentration of toluene for 20 days, were used to remove mixed gas of ethyl acetate and toluene. The two biofilters used a mixture of compost and lava, with the initial medium moisture content of 50%. The experimental results demonstrated several characteristics of the two biofilters:The maximum elimination capacities were about 400g·m-3·h-1 for ethyl acetate and 50 gm-3·h-1 for toluene;Under the condition that the empty bed residence time was 1.0 minute, for ethyl acetate concentration in the inlet air ranging from 2000 mg·m-3 to 4500mg·m-3 and toluene concentration ranging from 200mgm-3 to 400mg·m-3,the removal efficiency for binary VOCs of both biofilter RA was above 90%;Biofilter RA was better than biofilter RB in elimination capacity, stability and adaptability.

  8. Mining gene expression data for pollutants (dioxin, toluene, formaldehyde) and low dose of gamma-irradiation.

    Science.gov (United States)

    Moskalev, Alexey; Shaposhnikov, Mikhail; Snezhkina, Anastasia; Kogan, Valeria; Plyusnina, Ekaterina; Peregudova, Darya; Melnikova, Nataliya; Uroshlev, Leonid; Mylnikov, Sergey; Dmitriev, Alexey; Plusnin, Sergey; Fedichev, Peter; Kudryavtseva, Anna

    2014-01-01

    General and specific effects of molecular genetic responses to adverse environmental factors are not well understood. This study examines genome-wide gene expression profiles of Drosophila melanogaster in response to ionizing radiation, formaldehyde, toluene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. We performed RNA-seq analysis on 25,415 transcripts to measure the change in gene expression in males and females separately. An analysis of the genes unique to each treatment yielded a list of genes as a gene expression signature. In the case of radiation exposure, both sexes exhibited a reproducible increase in their expression of the transcription factors sugarbabe and tramtrack. The influence of dioxin up-regulated metabolic genes, such as anachronism, CG16727, and several genes with unknown function. Toluene activated a gene involved in the response to the toxins, Cyp12d1-p; the transcription factor Fer3's gene; the metabolic genes CG2065, CG30427, and CG34447; and the genes Spn28Da and Spn3, which are responsible for reproduction and immunity. All significantly differentially expressed genes, including those shared among the stressors, can be divided into gene groups using Gene Ontology Biological Process identifiers. These gene groups are related to defense response, biological regulation, the cell cycle, metabolic process, and circadian rhythms. KEGG molecular pathway analysis revealed alteration of the Notch signaling pathway, TGF-beta signaling pathway, proteasome, basal transcription factors, nucleotide excision repair, Jak-STAT signaling pathway, circadian rhythm, Hippo signaling pathway, mTOR signaling pathway, ribosome, mismatch repair, RNA polymerase, mRNA surveillance pathway, Hedgehog signaling pathway, and DNA replication genes. Females and, to a lesser extent, males actively metabolize xenobiotics by the action of cytochrome P450 when under the influence of dioxin and toluene. Finally, in this work we obtained gene expression signatures pollutants

  9. Central neurological abnormalities and multiple chemical sensitivity caused by chronic toluene exposure.

    Science.gov (United States)

    Lee, Y-L; Pai, M-C; Chen, J-H; Guo, Y L

    2003-10-01

    Multiple chemical sensitivity (MCS) is a syndrome in which multiple symptoms occur with low-level chemical exposure; whether it is an organic disease initiated by environmental exposure or a psychological disorder is still controversial. We report a 38-year-old male worker with chronic toluene exposure who developed symptoms such as palpitation, insomnia, dizziness with headache, memory impairment, euphoria while working, and depression during the weekend. Upon cessation of exposure, follow-up neurobehavioural tests, including the cognitive ability screening instrument and the mini-mental state examination, gradually improved and eventually became normal. Although no further toluene exposure was noted, non-specific symptoms reappeared whenever the subject smelled automotive exhaust fumes or paint, or visited a petrol station, followed by anxiety with sleep disturbance. During hospitalization for a toluene provocation test, there was no difference between pre-challenge and post-challenge PaCO(2), PaO(2), SaO(2) or pulmonary function tests, except some elevation of pulse rate. The clinical manifestations suggested that MCS was more relevant to psychophysiological than pathophysiological factors.

  10. Audition and exhibition to toluene - a contribution for the theme

    Directory of Open Access Journals (Sweden)

    Kulay, Luiz Alexandre

    2012-01-01

    Full Text Available Introduction: With the technological advances and the changes in the productive processes, the workers are displayed the different physical and chemical agents in its labor environment. The toluene is solvent an organic gift in glues, inks, oils, amongst others. Objective: To compare solvent the literary findings that evidence that diligent displayed simultaneously the noise and they have greater probability to develop an auditory loss of peripheral origin. Method: Revision of literature regarding the occupational auditory loss in displayed workers the noise and toluene. Results: The isolated exposition to the toluene also can unchain an alteration of the auditory thresholds. These audiometric findings, for ototoxicity the exposition to the toluene, present similar audiograms to the one for exposition to the noise, what it becomes difficult to differentiate a audiometric result of agreed exposition - noise and toluene - and exposition only to the noise. Conclusion: The majority of the studies was projected to generate hypotheses and would have to be considered as preliminary steps of an additional research. Until today the agents in the environment of work and its effect they have been studied in isolated way and the limits of tolerance of these, do not consider the agreed expositions. Considering that the workers are displayed the multiples agent and that the auditory loss is irreversible, the implemented tests must be more complete and all the workers must be part of the program of auditory prevention exactly displayed the low doses of the recommended limit of exposition.

  11. Influence of organobentonite structure on toluene adsorption from water solution

    Directory of Open Access Journals (Sweden)

    Nuria Vidal

    2012-12-01

    Full Text Available Due to increase water pollution by organic compound derived from hydrocarbons such as toluene, several alternative technologies for remediation of polluted water have been originated. In this work natural bentonites were modified with cetyltrimethylammonium (CTMA+ for obtaining organophilic bentonites. The obtained CTMA-bentonites would be suitable for use as adsorbents of toluene present in water. The influence of structural characteristics of CTMA-bentonites on their adsorption capacity was studied. It was shown that adsorption of toluene depended on homogeneous interlayer space associated with arrangements of CTMA+ paraffin-monolayer and bilayer models, accompanied by a high degree ordering of the carbon chain of organic cation in both arrangements. However, packing density would not have an evident influence on the retention capacity of these materials. The solids obtained were characterized by chemical analysis, X-ray diffractions and infrared spectroscopy. Toluene adsorption was measured by UV-visible spectrophotometer. Adsorption capacity was studied by determining adsorption isotherms and adsorption coefficient calculation. The adsorption isotherms were straight-line indicating a partition phenomenon of toluene between the aqueous and organic phase present in organophilic bentonites.

  12. Removal of Low Concentration Toluene Vapor in a Biotrickling Filter

    Institute of Scientific and Technical Information of China (English)

    ZHOU Min; WU Guang-qian; WANG Li-ping; ZHANG Xing

    2004-01-01

    A laboratory-scale biotrickling filter packed with ceramic lasing rings is built to remove artificial toluene vapor. The performance of biotrickling filter under different superficial gas velocities and inlet toluene concentrations is evaluated. The start-up period is 6 days by using the novel "gas-liquid phase synchronic inoculation" method and adding the optimal components nutrient liquid. The experiments lasts 3 months, and different sets of continuous tests are conducted at an inlet toluene concentration ranging from 30 mg/m3 to 1 223 mg/m3 and at superficial gas velocities ranging from 123 m/h to 370 m/h (corresponding to residence time 9.75-29.3 s). The effect of nutrient liquid recycling rate on biotrickling filter performance is also evaluated. The result shows that the maximum elimination capacity is 152.1 g/(m3*h) at the inlet toluene concentration of 1 223 mg/m3 and the superficial gas velocity of 205 m/h(corresponding to a residence time of 17.6 s). The average toluene removal efficiency reaches 80% in the experiments period, and high water content has a negative effect on biotrickling filter performance. The microscope observation of the micro-organism in the biofilm shows that the Pseudomonas is the dominant group of the mixing microbial culture in the biofilm.

  13. Smog Chamber Studies of Toluene Photooxidation By Ho Radicals

    Science.gov (United States)

    Barbu, A.; Bienenstock, Y.; Arias, M. C.; Collin, F.; Hastie, D. R.

    Two series of smog chamber experiments have been conducted to determine the par- ticulate yield from toluene photo oxidation and to investigate the dependence of the yield on experimental factors. Toluene was oxidized by HO radicals in the presence of NO by irradiating mixtures of toluene/isopropylnitrite/NO with UV light and experiments were done in the presence and absence of ammonium sulfate seed particles. Aerosol formation and growth was monitored using size distributions obtained from a Differential Mobility Analyzer and a Condensation Nucleus Counter. A Gas Chromatograph with an FID detector was used to monitor the toluene loss and a Chemiluminescence Analyzer measured the NO concentration. As expected the ozone concentration was found to be extremely low so the complicating ozone reactions are minimized. The experimental yields (the ratio between the organic aerosol mass formed and the mass of toluene reacted) were found to cluster around 10% but there were cases where the yields were as low as 1.7% and as high as 20%. The on-going work is focused on understanding the factors leading to the variability of experimental yields and on analyzing the data in the framework of the current gas/particle partitioning theory.

  14. Toluene in sewage and sludge in wastewater treatment plants.

    Science.gov (United States)

    Mrowiec, Bozena

    2014-01-01

    Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 μg/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and dephosphatation processes, the presence of volatile fatty acids (VFAs) in sewage is required. VFAs are the main product of organic matter hydrolysis from sewage sludge. However, no attention has been given to other products of the process. It has been found that in parallel to VFA production, toluene formation occurred. The formation of toluene in municipal anaerobic sludge digestion processes was investigated. Experiments were performed on a laboratory scale using sludge from primary and secondary settling tanks of municipal treatment plants. The concentration of toluene in the digested sludge from primary settling tanks was found to be about 42,000 μg/L. The digested sludge supernatant liquor returned to the biological dephosphatation and denitrification processes for sewage enrichment can contain up to 16,500 μg/L of toluene.

  15. Source proximity and meteorological effects on residential outdoor VOCs in urban areas: Results from the Houston and Los Angeles RIOPA studies.

    Science.gov (United States)

    Kwon, Jaymin; Weisel, Clifford P; Morandi, Maria T; Stock, Thomas H

    2016-12-15

    Concentrations of volatile organic compounds (VOCs) measured outside homes in Houston, TX and Los Angeles, CA were characterized by the effects of source proximity and meteorological factors. Benzene, toluene, ethylbenzene, m,p-xylene, o-xylene (BTEX), methyl tert butyl ether (MTBE), tetrachloroethylene (perchloroethylene, PCE), and carbon tetrachloride (CCl4) were examined. Multiple stepwise regression analysis converged the best-fit models with predictors from meteorological conditions and the proximity to specific point, area, and mobile sources on the residential outdoor VOC concentrations. Negative associations of wind speed with concentrations demonstrated the effect of dilution by high wind speed. Atmospheric stability increase was associated with concentration increase. Petrochemical source proximity was a significant predictor for BTEX and MTBE concentrations in Houston. Ethylbenzene and xylene source proximity was a significant predictor in Los Angeles. Close proximity to area sources such as scrap metal recycling or dry cleaning facilities increased the MTBE, PCE, and CCl4 concentrations in Houston and Los Angeles. Models for ethylbenzene, m,p-xylene, and MTBE in Houston, and benzene in Los Angeles explained that for the median values of the meteorological factors, homes closest to influential highways would have concentrations that were 1.7-2.2 fold higher than those furthest from these mobile emission sources. If the median distance to sources were used in the models, the VOC concentrations varied 1.7 to 6.6 fold as the meteorological conditions varied over the observed range. These results highlight that each urban area is unique and localized sources need to be carefully evaluated to understand potential contributions to VOC air concentrations near residences, which influence baseline indoor air concentrations and personal exposures. Results of this study could assist in the appropriate design of monitoring networks for community-level sampling. They

  16. Synergistic effect of UV pretreated Fe-ZSM-5 catalysts for heterogeneous catalytic complete oxidation of VOC: A technology development for sustainable use.

    Science.gov (United States)

    Aziz, Abdul; Kim, Kwang Soo

    2017-10-15

    In this work, the performance of benzene, toluene, ethylbenzene, and xylene (BTEX) removal and degradation from gas, air streams on UV pretreated Fe-ZSM-5 in a batch reactor at room temperature were studied. The Fe-ZSM-5 zeolite catalyst was prepared by hydrothermal reaction method. The influence of UV pre-irradiation time on the removal of BTEX were assessed by varying the time, ranging from 15min to 60smin. Then, sustainability of the activation of the catalyst resulted by UV pretreatment was studied by the four-cycle experiment with one time UV irradiation and after each cycle irradiation followed by BTEX removal after every cycle respectively. The results of BTEX removal depicted that 30min of UV pretreatment was sufficient for complete organics removal. The UV pretreatment effect on the catalytic oxidation and the stability of the catalyst were studied by modern instrumental techniques. The novelty of the process was the sustainable reuse of catalyst with persistent VOC removal, which works on the -adsorption-oxidation-regeneration-adsorption- cycle, which was confirmed by the characterization studies of the catalyst after four runs. The results revealed that the change in the structure, stability, morphology, and removal efficiency of the catalyst during the experiments was negligible. The VOC degradation mechanism studies showed that the oxidation occurs due to the formation of free radicals as well as hydroxyl ions, so named it heterogeneous photo-Fenton oxidation. The residual materials analysis showed the complete mineralization of VOC except small amount of acetone as oxidation product. Lastly, the kinetics of the VOC removal was studied. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Mapping methane sources and emissions over California from direct airborne flux and VOC source tracer measurements

    Science.gov (United States)

    Guha, A.; Misztal, P. K.; Peischl, J.; Karl, T.; Jonsson, H. H.; Woods, R. K.; Ryerson, T. B.; Goldstein, A. H.

    2013-12-01

    fluxes were obtained using the virtual disjunct eddy covariance method and from Wavelet Analysis along flight tracks flown in the mixed layer. Preliminary analysis of mixing ratio measurements indicate that high concentrations of CH4 occur consistently while flying above the Central Valley that are correlated to large enhancements of methanol which is an important dairy and livestock emissions tracer. The elevated CH4 mixing ratios along the eastern edge of the San Joaquin Valley highlight the contribution of topography and emissions transport to local ambient levels of CH4. Large enhancements of CH4, benzene and toluene are also observed while flying over the oil production facilities in western part of Kern county (state's top oil producing county, 10% of US production) suggesting the likelihood of fugitive emissions in the region. VOC tracer analysis is used to evaluate the source of high CH4 emissions encountered along the eastern edge of the central Sacramento valley where fugitive emissions from natural gas fields and cultivation of rice are likely sources. Plumes from biomass burning, landfills and refineries encountered during different flights are also investigated. Eddy covariance based CH4 flux estimates are derived for various sources and compared with ';bottom-up' inventory estimates to verify/validate the CA methane inventory for major sources.

  18. Measurements of VOCs in Mexico City during the MILAGRO Campaign

    Science.gov (United States)

    Baker, A. K.; Beyersdorf, A. J.; Blake, N. J.; Meinardi, S.; Atlas, E.; Rowland, F.; Blake, D. R.

    2006-12-01

    During March of 2006 we participated in MILAGRO (Megacities Initiative: Local and Global Research Observations), a multi-platform campaign to measure pollutants in and in outflow from the Mexico City metropolitan area. As part of MILAGRO we collected whole air canister samples at two Mexico City ground sites: the Instituto Mexicano del Petroleo, located in the city, northeast of the center, and the Universidad Technologica de Tecamac, a suburban site approximately 50 km northeast of the city center. Samples were also collected in various other locations throughout Mexico City. Over 300 whole air samples were collected and analyzed for a wide range of volatile organic compounds (VOCs) including methane, carbon monoxide, nonmethane hydrocarbons (NMHCs) and halocarbons. Propane was the most abundant NMHC at both the urban and suburban locations, with mixing ratios frequently in excess of 10 parts per billion at both locations. This is likely the result of the widespread use of liquefied petroleum gas (LPG) of which propane is the major component. For most species, median mixing ratios at the urban sites were significantly greater than at the suburban site. Here we compare results from both urban and suburban locations and also examine the influence of transport on the composition of outflow from Mexico City.

  19. Gastrophysa polygoni herbivory on Rumex confertus: single leaf VOC induction and dose dependent herbivore attraction/repellence to individual compounds.

    Science.gov (United States)

    Piesik, Dariusz; Wenda-Piesik, Anna; Kotwica, Karol; Łyszczarz, Alicja; Delaney, Kevin J

    2011-11-15

    We report large induction (>65(fold) increases) of volatile organic compounds (VOCs) emitted from a single leaf of the invasive weed mossy sorrel, Rumex confertus Willd. (Polygonaceae), by herbivory of the dock leaf beetle, Gastrophysa polygoni L. (Coleoptera: Chrysomelidae). The R. confertus VOC blend induced by G. polygoni herbivory included two green leaf volatiles ((Z)-3-hexenal, (Z)-3-hexen-1-yl acetate) and three terpenes (linalool, ß-caryophyllene, (E)-ß-farnesene). Uninjured leaves produced small constitutive amounts of the GLVs and barely detectable amounts of the terpenes. A Y-tube olfactometer bioassay revealed that both sexes of adult G. polygoni were attracted to (Z)-3-hexenal and (Z)-3-hexen-1-yl acetate at a concentration of 300 ng h(-1). No significant G. polygoni attraction or repellence was detected for any VOC at other concentrations (60 and 1500 ng h(-1)). Yet, G. polygoni males and females were significantly repelled by (or avoided) at the highest test concentration (7500 ng h(-1)) of both GLVs and (E)-ß-farnesene. Mated male and female G. polygoni might be attracted to injured R. confertus leaves, but might avoid R. confertus when VOC concentrations (especially the terpene (E)-ß-farnesene) suggest high overall plant injury from conspecifics, G. viridula, or high infestations of other herbivores that release (E)-ß-farnesene (e.g., aphids). Tests in the future will need to examine G. polygoni responses to VOCs emitted directly from uninjured (constitutive) and injured (induced) R. confertus, and examine whether R. confertus VOC induction concentrations increase with greater tissue removal on a single leaf and/or the number of leaves with feeding injury.

  20. TO PURGE OR NOT TO PURGE? VOC CONCENTRATION ...

    Science.gov (United States)

    Soil vapor surveys are commonly used as a screening technique to delineate volatile organic compound (VOC) contaminant plumes and provide information for soil sampling plans. Traditionally, three purge volumes of vapor are removed before a sample is collected. One facet of this study was to evaluate the VOC concentrations lost during purging and explore the potential implications of those losses. The vapor data was compared to collocated soil data to determine if any correlation existed between the VOC concentrations. Two different methods for soil vapor collection were compared: 1) active/micro-volume; and 2) active/macro-volume. The active/micro-volume vapor sample had total line purge volume of 1.25 mL and the active/macro-volume vapor sample had a total line purge volume of 15 mL. Six line purge volumes were collected for each vapor sampling technique, with the fourth purge volume representing the traditional sample used for site screening data. Each sample was collected by gas tight syringe and transferred to a thermal de sorption tube for sorption, transport, and analysis. Following the removal of the soil vapor samples, collocated soil samples were taken. For both active vapor sampling techniques, the VOC concentrations in the first three purge volumes exceeded the VOC concentrations in the last three purge volumes. This implies that the general rule of removal of three purge volumes prior to taking a sample for analysis could lead to underestimating the

  1. Antipyrine clearance during experimental and occupational exposure to toluene

    DEFF Research Database (Denmark)

    Døssing, M; Bælum, Jesper; Lundqvist, G R

    1983-01-01

    into four groups. Eighteen printers and 21 controls were exposed to 100 ppm of toluene during 6.5 hours in an exposure chamber. The remaining 18 printers and 18 controls were exposed to 0 ppm of toluene under similar conditions. The salivary clearance of antipyrine was measured immediately after the stay...... in the exposure chamber to investigate a possible acute change in liver function and was repeated two weeks later, shortly before the summer vacation. Antipyrine clearance was measured again at the end of the summer vacation-four weeks after exposure. To study a possible effect of chronic exposure on antipyrine...... clearance 12 printing trade workers with 17 years (median) of occupational exposure to toluene vapour at concentrations of about 100 ppm were investigated before and four weeks after cessation of exposure. No difference in antipyrine clearance was found either within the groups or between the groups at any...

  2. Calorimetric Measurements at Low Temperatures in Toluene Glass and Crystal

    Science.gov (United States)

    Alvarez-Ney, C.; Labarga, J.; Moratalla, M.; Castilla, J. M.; Ramos, M. A.

    2017-04-01

    The specific heat of toluene in glass and crystal states has been measured both at low temperatures down to 1.8 K (using the thermal relaxation method) and in a wide temperature range up to the liquid state (using a quasiadiabatic continuous method). Our measurements therefore extend earlier published data to much lower temperatures, thereby allowing to explore the low-temperature "glassy anomalies" in the case of toluene. Surprisingly, no indication of the existence of tunneling states is found, at least within the temperature range studied. At moderate temperatures, our data either for the glass or for the crystal show good agreement with those found in the literature. Also, we have been able to prepare bulk samples of toluene glass by only doping with 2% mol ethanol instead of with higher impurity doses used by other authors.

  3. Mass Spectrometry Study of OH-initiated Photooxidation of Toluene

    Institute of Scientific and Technical Information of China (English)

    Ming-qiang Huang; Wei-iun Zhang; Zhen-ya Wang; Li Fang; Rui-hong Kong; Xiao-bin Shan; Fu-yi Liu; Liu-si Sheng

    2011-01-01

    The composition of products formed from photooxidation of the aromatic hydrocarbon toluene was investigated.The OH-initiated photooxidation experiments were conducted by irradiating toluene/CH3ONO/NO/air mixtures in a smog chamber,the gaseous products were detected under the supersonic beam conditions by utilizing vacuum ultraviolet photoionization mass spectrometer using synchrotron radiation in real-time.And an aerosol time-of-flight mass spectrometer was used to provide on-line measurements of the individual secondary organic aerosol particle resulting from irradiating toluene.The experimental results demonstrated that there were some differences between the gaseous products and that of particle-phase,the products of glyoxal,2-hydroxyl-3-oxo-butanal,nitrotoluene,and methyl-nitrophenol only existed in the particle-phase.However,furane,methylglyoxal,2-methylfurane,benzaldehyde,cresol,and benzoic acid were the predominant photooxidation products in both the gas phase and particle phase.

  4. Toluene optical fibre sensor based on air microcavity in PDMS

    Science.gov (United States)

    Kacik, Daniel; Martincek, Ivan

    2017-03-01

    We prepared and demonstrated a compact, simple-to-fabricate, air microcavity in polydimethylsiloxane (PDMS) placed at the end of a single-mode optical fibre. This microcavity creates a Fabry-Perot interferometer sensor able to measure concentrations of toluene vapour in air. Operation of the sensor is provided by diffusion of the toluene vapour to the PDMS, and the consequent extension of length d of the air microcavity in PDMS. The sensor response for the presence of vapours is fast and occurs within a few seconds. By using the prepared sensor toluene vapour concentration in air can be measured in the range from about 0.833 g.m-3 to saturation, with better sensitivity than 0.15 nm/g.m-3 up to maximal sensitivity 1.4 nm/g.m-3 at around concentration 100 g.m-3 in time 5 s.

  5. Effects of toluene exposure on signal transduction: toluene reduced the signaling via stimulation of human muscarinic acetylcholine receptor m2 subtypes in CHO cells.

    Science.gov (United States)

    Tsuga, Hirofumi; Haga, Tatsuya; Honma, Takeshi

    2002-07-01

    The organic solvent toluene is used widely in industry and is toxic to the central nervous system (CNS). To clarify the mechanisms of CNS toxicity following toluene exposure, especially with respect to the G protein-coupling of receptors, we determined the effects of toluene on the activation of Gi by stimulating human muscarinic acetylcholine receptor m2 subtypes (hm2 receptors) expressed in Chinese hamster ovary (CHO) cells. We first examined whether toluene affects the inhibition of adenylyl cyclase by Gi. The attenuation of forskolin-stimulated cAMP formation by the stimulation of hm2 receptors was reduced in a medium containing toluene. Next, we determined the effects of toluene on carbamylcholine-stimulated [35S]GTPgammaS binding using membrane fractions of CHO cell expressing hm2 receptors. Carbamylcholine-stimulated [35S]GTPgammaS binding activity was markedly reduced when assayed using reaction buffers containing toluene. However, carbamylcholine-stimulated [35S]GTPgammaS binding activity was essentially unchanged following pretreatment of the cells with a toluene-saturated medium prior to membrane isolation. Toluene pretreatment and the toluene itself did not alter the characteristics of the binding of carbamylcholine and [3H]N-methylscopolamine to hm2 receptors. On the contrary of the effect of toluene for [35S]GTPgammaS binding, the effect of toluene for attenuation of forskolin-stimulated cAMP formation by the stimulation of hm2 receptors was irreversible. These observations indicate that toluene acts as an inhibitor of the signal transduction via hm2 receptor stimulation in CHO cells, and at least two mechanisms exist in the inhibition mechanisms by toluene.

  6. Emission characteristics of VOCs from three fixed-roof p-xylene liquid storage tanks.

    Science.gov (United States)

    Lu, Chungsying; Huang, Hsiaoyun; Chang, Shenteng; Hsu, Shihchieh

    2013-08-01

    This study evaluates emission characteristics of volatile organic compounds (VOCs) caused by standing loss (L S) and working loss (L W) of three vertical fixed-roof p-xylene (p-X) liquid tanks during 1-year storage and filling operation. The annual net throughput of the tanks reached 70,446 t, resulting in 9,425 kg of p-X vapor emission including 5,046 kg of L S (53.54 %) and 4,379 kg of L W (46.46 %). The estimated L W of AP-42 displayed better agreement with the measured values of a VOC detector than the estimated L S of AP-42. The L S was best correlated with the liquid height of the tanks, while the L W was best correlated with the net throughput of the tanks. As a result, decreasing vapor space volume of the tanks and avoiding high net throughput of the tanks in a high ambient temperature period were considered as effective means to lessen VOC emission from the fixed-roof organic liquid storage tank.

  7. Biogenic C5 VOCs: release from leaves after freeze-thaw wounding and occurrence in air at a high mountain observatory

    Science.gov (United States)

    Fall, Ray; Karl, Thomas; Jordan, Alfons; Lindinger, Werner

    During investigations of the formation of volatile organic compounds (VOCs) in leaves, we observed C5 VOCs during leaf drying, senescence, and following freeze-thaw damage. VOCs were quantified by proton-transfer-reaction mass spectrometry (PTR-MS). In freeze-damaged leaves, VOC products were verified with a gas chromatography PTR-MS system, showing that a variety of plants produced 1-penten-3-ol and 1-penten-3-one with smaller amounts of 2(Z)-penten-1-ol and pentenals; similar VOCs have been detected in soybean seed homogenates (Gardner et al., J. Agric. Food Chem. 44 (1996) 882). Most plants wounded in this way also released hexenals and hexanal, and clover also released methylbutanals. The formation of the C5 products was oxygen-dependent, consistent with the involvement of the enzyme lipoxygenase, and pentenone appeared to form independent of an alcohol dehydrogenase reaction; the latter is apparently disrupted by the freeze-thaw treatment. In parallel with these laboratory experiments, on-line PTR-MS measurements of ambient air were conducted at the Sonnblick Observatory in the Austrian Alps (3106 m a.s.l.). Following a hard freeze in central Austria, substantial amounts of C5 VOCs, ranging from 300 pptv to 6 ppbv and including 1-penten-3-ol, methylbutanals and probably pentenone, were detected at this site for several days peaking after midnight. Factor analysis supported their biogenic origin. We speculate that these VOCs were derived from freeze-damaged local vegetation by processes similar to those seen in laboratory freezing studies. If confirmed, these results suggest that leaf-freezing events in forests will give rise to the release of substantial levels of reactive C5 and C6 VOCs that can contribute to regional tropospheric chemistry.

  8. Arabidopsis thaliana as Bioindicator of Fungal VOCs in Indoor Air

    Science.gov (United States)

    Hung, Richard; Yin, Guohua; Klich, Maren A.; Grimm, Casey; Bennett, Joan W.

    2016-01-01

    In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and β-farnesene), and β-caryophyllene were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

  9. Metabolic interaction between toluene, trichloroethylene and n-hexane in humans

    DEFF Research Database (Denmark)

    Bælum, Jesper; Mølhave, Lars; Hansen, S H

    1998-01-01

    This human experimental study describes the mutual metabolic interaction between toluene, trichloroethylene, and n-hexane.......This human experimental study describes the mutual metabolic interaction between toluene, trichloroethylene, and n-hexane....

  10. Effects of Isoprene- and Toluene-Generated Smog on Allergic ...

    Science.gov (United States)

    Reactions of organic compounds with nitric oxide (NO) and sunlight produce complex mixtures of pollutants including secondary organic aerosol (SOA), ozone (O3), nitrogen dioxide (NO2), and reactive aldehydes. The health effects of these photochemical smog mixtures in susceptible populations including asthmatics are unclear. We assessed effects of smog generated from mixtures of NO with isoprene (IS) or toluene (TL) on allergic inflammatory responses in Balb/cJ mice. House dust mite (HDM)-sensitized or control mice were all challenged with HDM intranasally 1 d prior to whole-body inhalation exposure to IS (chamber average 509 ppb NO2, 246 ppb O3, and 160 g/m3 SOA), TL (217 ppb NO2, 129 ppb O3, and 376 g/m3 SOA), or HEPA-filtered air (4 h/d for 2 days). Mice were necropsied within 3 h after the second exposure (2 d post-HDM challenge). Assessment of breathing parameters during exposure with double-chamber plethysmography showed a trend for increased specific airway resistance and decreased minute volume during the second day of TL exposure in both non-allergic and HDM-allergic mice. HDM-allergic air-exposed mice had significant increases in numbers of bronchoalveolar lavage (BAL) alveolar macrophages (AM) and eosinophils (EO), and trends for increases in BAL indices of lung injury in comparison with non-allergic air-exposed mice. Exposure to either IS or TL attenuated the increases in AM, EO, and lung injury markers in HDM-allergic mice. The results of this

  11. Adsorption of Toluene and Paraxylene from Aqueous Solution Using Pure and Iron Oxide Impregnated Carbon Nanotubes: Kinetics and Isotherms Study

    Science.gov (United States)

    Abbas, Aamir; Ihsanullah; Al-Baghli, Nadhir A. H.

    2017-01-01

    Multiwall carbon nanotubes (CNTs) and iron oxide impregnated carbon nanotubes (CNTs-iron oxide) were investigated for the adsorption of hazardous toluene and paraxylene (p-xylene) from aqueous solution. Pure CNTs were impregnated with iron oxides nanoparticles using wet impregnation technique. Various characterization techniques including thermogravimetric analysis, scanning electron microscopy, elemental dispersion spectroscopy, X-ray diffraction, and nitrogen adsorption analysis were used to study the thermal degradation, surface morphology, purity, and surface area of the materials. Batch adsorption experiments show that iron oxide impregnated CNTs have higher degree of removal of p-xylene (i.e., 90%) compared with toluene (i.e., 70%), for soaking time 2 h, with pollutant initial concentration 100 ppm, at pH 6 and shaking speed of 200 rpm at 25°C. Pseudo-second-order model provides better fitting for the toluene and p-xylene adsorption. Langmuir and Freundlich isotherm models demonstrate good fitting for the adsorption data of toluene and p-xylene. PMID:28386208

  12. Degradation of toluene and m-xylene and transformation of o-xylene by denitrifying enrichment cultures.

    Science.gov (United States)

    Evans, P J; Mang, D T; Young, L Y

    1991-01-01

    Seven different sources of inocula that included sediments, contaminated soils, groundwater, process effluent, and sludge were used to establish enrichment cultures of denitrifying bacteria on benzene, toluene, and xylenes in the absence of molecular oxygen. All of the enrichment cultures demonstrated complete depletion of toluene and partial depletion of o-xylene within 3 months of incubation. The depletion of o-xylene was correlated to and dependent on the metabolism of toluene. No losses of benzene, p-xylene, or m-xylene were observed in these initial enrichment cultures. However, m-xylene was degraded by a subculture that was incubated on m-xylene alone. Complete carbon, nitrogen, and electron balances were determined for the degradation of toluene and m-xylene. These balances showed that these compounds were mineralized with greater than 50% conversion to CO2 and significant assimilation into biomass. Additionally, the oxidation of these compounds was shown to be dependent on nitrate reduction and denitrification. These microbial degradative capabilities appear to be widespread, since the widely varied inoculum sources all yielded similar results. PMID:2014990

  13. Removal of toluene from water by photocatalytic oxidation with activated carbon supported Fe(3+)-doped TiO2 nanotubes.

    Science.gov (United States)

    Yuan, Rongfang; Zhou, Beihai; Ma, Li

    2014-01-01

    In this work, activated carbon (AC)-supported TiO2 containing 1.0% (mass percent) of 1.0 at.% (atomic percent) Fe(3+)-doped TiO2 nanotubes (Fe-TNTs) were successfully synthesized. The catalyst was used to effectively decompose toluene in water under O3/UV conditions, and some properties including the morphology, X-ray photoelectron spectroscopy, X-ray diffraction patterns, specific surface area and UV-visible diffuse reflectance spectroscopy were analyzed. A removal efficiency of 90.7% was achieved in the presence of fresh AC-supported Fe-TNTs calcined at 550 °C, with a pseudo-first-order rate constant of 0.038/min. The removal efficiency of toluene was reduced when the catalysts were repeatedly used, since the amount of adsorption sites of the supporting substrates decreased. However, even after AC-supported catalyst was used four times, the removal efficiency of toluene was still sufficient in water treatment. The enhanced photocatalytic activity of AC-supported Fe-TNTs was related to the synergistic effect of AC adsorption and Fe-TNTs photocatalytic ozonation. The water from a petrochemical company in China was used to obtain the removal efficiency of the pollutants, and the toluene and total organic carbon removal efficiencies were 69.9% and 58.3%, respectively.

  14. On-Road Measurement of Vehichle VOC Emission Measurements During the 2003 Mexico City Metropolitan Area Field Campaign

    Science.gov (United States)

    Knighton, W. B.; Rogers, T.; Grimsrud, E.; Herndon, S.; Allwine, E.; Lamb, B.; Velasco, E.; Westberg, H.

    2004-12-01

    In the spring of 2003 (April 1-May 5), a multinational team of experts conducted an intensive, five-week field campaign in the Mexico City Metropolitan Area (MCMA). The overall goal of this effort was to contribute to the understanding of the air quality problem in megacities. As part of the campaign the Aerodyne Mobile Laboratory was equipped with state-of-the-art analytical instruments and deployed for measuring a variety of vehicle emissions in real time including CO2, NO2, NH3, HCHO, VOC's and volatile (at 600 °C) aerosol. The on-road measurement of vehicle VOC emissions were performed using a commercial version of the IONICON PTR-MS modified to operate onboard the mobile lab platform. A summary of the PTR-MS results from these and supporting laboratory experiments will be presented and discussed. In particular, selected chase events will be presented to illustrate the utility of the PTR-MS technique for characterizing vehicle VOC emission profiles in real time. VOC emission profiles for different vehicle engine types which include gasoline, diesel and compressed natural gas will be discussed and compared to the measurements from other high time response instruments deployed on the Aerodyne mobile van.

  15. VOC emission control by circulating fluidized bed adsorption; Controle de l'emission de composes organiques volatils par adsorption en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Song, W.

    2003-12-15

    This work deals with the circulating fluidized bed technology, applied to the elimination by adsorption of volatile organic compounds (VOCs), like toluene, in a gas flow. In the process, the adsorbent (millimetric spherical grains of micro-porous carbon) is moved by a strong flow rate of gas inside a vertical tube without lining. Mass and heat transfers are very important and important volumes of compounds can be processed. This work presents the determination of the adsorption equilibrium, the description of the experimental facility and of the results of experiments, the development of an original model of the process which combines a flow model and a mass transfer model, a parametric study of this model, and finally, some extensions of the process principle to staged operations with pressure variation or temperature variation cycles. (J.S.)

  16. 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.

  17. Metabolism of benzene, toluene, and xylene hydrocarbons in soil

    Science.gov (United States)

    Tsao; Song; Bartha

    1998-12-01

    Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the production of 14CO2 were monitored. At the conclusion of each experiment, 14C distribution in solvent-extractable polymers, biomass, and humic material was determined, obtaining 14C mass balances of 85 to 98%. BTX compounds were extensively mineralized in soil, regardless of whether they were presented singly or in combinations. No evidence was obtained for the formation of solvent-extractable polymers from xylenes in soil, but 14C distribution in biomass (5 to 10%) and humus (12 to 32%) was unusual for all BTX compounds and especially for toluene and the xylenes. The results suggest that catechol intermediates of BTX degradation are preferentially polymerized into the soil humus and that the methyl substituents of the catechols derived from toluene and especially from xylenes enhance this incorporation. In contrast to inhibitory residues formed from xylene cometabolism in culture, the humus-incorporated xylene residues showed no significant toxicity in the Microtox assay.

  18. Metabolism of Benzene, Toluene, and Xylene Hydrocarbons in Soil†

    Science.gov (United States)

    Tsao, C.-W.; Song, H.-G.; Bartha, R.

    1998-01-01

    Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the production of 14CO2 were monitored. At the conclusion of each experiment, 14C distribution in solvent-extractable polymers, biomass, and humic material was determined, obtaining 14C mass balances of 85 to 98%. BTX compounds were extensively mineralized in soil, regardless of whether they were presented singly or in combinations. No evidence was obtained for the formation of solvent-extractable polymers from xylenes in soil, but 14C distribution in biomass (5 to 10%) and humus (12 to 32%) was unusual for all BTX compounds and especially for toluene and the xylenes. The results suggest that catechol intermediates of BTX degradation are preferentially polymerized into the soil humus and that the methyl substituents of the catechols derived from toluene and especially from xylenes enhance this incorporation. In contrast to inhibitory residues formed from xylene cometabolism in culture, the humus-incorporated xylene residues showed no significant toxicity in the Microtox assay. PMID:9835584

  19. Modelling toluene oxidation : Incorporation of mass transfer phenomena

    NARCIS (Netherlands)

    Hoorn, J.A.A.; van Soolingen, J.; Versteeg, G. F.

    2005-01-01

    The kinetics of the oxidation of toluene have been studied in close interaction with the gas-liquid mass transfer occurring in the reactor. Kinetic parameters for a simple model have been estimated on basis of experimental observations performed under industrial conditions. The conclusions for the m

  20. Modelling toluene oxidation : Incorporation of mass transfer phenomena

    NARCIS (Netherlands)

    Hoorn, J.A.A.; van Soolingen, J.; Versteeg, G. F.

    The kinetics of the oxidation of toluene have been studied in close interaction with the gas-liquid mass transfer occurring in the reactor. Kinetic parameters for a simple model have been estimated on basis of experimental observations performed under industrial conditions. The conclusions for the

  1. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    Science.gov (United States)

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  2. Electrocardiographic effects of toluene in the anesthetized rat.

    Science.gov (United States)

    Vidrio, H; Magos, G A; Lorenzana-Jimenez, M

    1986-01-01

    The influence of inhalation of near lethal quantities of toluene on some ECG parameters, as well as the possible cardiac sensitizing effect of the solvent, were determined in chloralose-anesthetized rats. These actions were compared with those of its close analogue benzene. Both solvents produced tachycardia; toluene increased the duration of QRS and specially PR, while benzene decreased P wave duration. No other systematic changes in ECG morphology or evidence of arrhythmia were observed. Toluene appeared to decrease the number of ectopic beats induced by epinephrine, in contrast to benzene, which increased it markedly. These results suggest that toluene administered by inhalation up to near lethal doses is devoid of untoward ECG effect in the chloralose-anesthetized rat, its only action being a decrease in intraventricular and particularly AV conduction. It does not share the myocardial sensitizing properties of benzene and in fact appears to elicit some protection from the arrhythmogenic effects of epinephrine, although no definite conclusions as to this action can be derived due to limitations in the experimental model used.

  3. Modelling toluene oxidation : Incorporation of mass transfer phenomena

    NARCIS (Netherlands)

    Hoorn, J.A.A.; van Soolingen, J.; Versteeg, G. F.

    2005-01-01

    The kinetics of the oxidation of toluene have been studied in close interaction with the gas-liquid mass transfer occurring in the reactor. Kinetic parameters for a simple model have been estimated on basis of experimental observations performed under industrial conditions. The conclusions for the m

  4. Instrument for benzene and toluene emission measurements of glycol regenerators

    Science.gov (United States)

    Hanyecz, Veronika; Mohácsi, Árpád; Puskás, Sándor; Vágó, Árpád; Szabó, Gábor

    2013-11-01

    We introduce an in-field and in-explosive atmosphere useable instrument, which can measure the benzene and toluene concentration in two gas and two glycol samples produced by natural gas dehydration units. It is a two-phase, on-line gas chromatograph with a photoacoustic spectroscopy based detector. The time resolution is 10 min per cycle and the minimum detectable concentrations are 2 mg m-3 for benzene, 3 mg m-3 for toluene in natural gas, and 5 g m-3 for benzene and 6 g m-3 for toluene in glycol. Test measurements were carried out at a dehydration plant belonging to MOL Hungarian Oil and Gas Company. Benzene and toluene emissions of gas dehydration unit are calculated from the measured values based on mass balance of a glycol regenerator. The relationship between the outdoor temperature and the measured concentration was observed which is caused by temperature-dependent operation of the whole dehydration unit. Emission decreases with increase of outdoor temperature.

  5. Nonionic surfactant Brij35 effects on toluene biodegradation in a ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... African Journal of Biotechnology Vol. 8 (20), pp. ... Nonionic surfactant effects on the toluene dissolved in the water phase and biodegradation kinetic behaviors .... Peat (industrial grade from KekkilaOyj, Tuusula, Finland) was dried at 105°C ... sludge obtained from the wastewater treatment plant in Hsinchu.

  6. 75 FR 52768 - Withdrawal of Approval of New Animal Drug Applications; Dichlorophene and Toluene Capsules

    Science.gov (United States)

    2010-08-27

    ...; Dichlorophene and Toluene Capsules AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food... use of dichlorophene and toluene deworming capsules for cats and dogs. In a final rule published... withdraw approval of NADA 101-497 for TINY TIGER (dichlorophene/toluene) Worming Capsules, NADA 101-498 for...

  7. Low VOC drying of lumber and wood panel products. Progress report No. 8

    Energy Technology Data Exchange (ETDEWEB)

    Su, W.; Yan, H.; Hooda, U.; Wild, M.P.; Banerjee, S. [Inst. of Paper Science and Technology, Atlanta, GA (United States); Shmulsky, R.; Thompson, A.; Ingram, L.; Conners, T. [Mississippi State Univ., MS (United States)

    1998-07-01

    This study was initiated by an Institute of Paper Science and Technology finding that heating softwood in a low-headspace environment removed much of the VOCs without removing the water. This offered the possibility of removing VOCs from wet wood, capturing them as a product, and then drying the VOC-depleted wood conventionally with little or no VOC controls. Two means of low-headspace heating were explored: steam and radiofrequency (RF). It was found in the previous year, that while both steam and RF were able to drive out VOCs, steam was impracticably slow for lumber. Hence the effect of RF or microwave on wood was the principal focus of the work reported here. Finally, in order to understand the mechanism of VOC release, the transport of the VOCs in wood was studied, together with the seasonal effects that influence VOC concentration in trees.

  8. PM2.5 and volatile organic compounds (VOCs) in ambient air: a focus on the effect of meteorology.

    Science.gov (United States)

    Giakoumi, A; Maggos, Th; Michopoulos, J; Helmis, C; Vasilakos, Ch

    2009-05-01

    PM(2.5) and VOCs (benzene, toluene, m-p-o-xylenes) concentrations were measured in an urban and a suburban site in Athens, Greece, during the period between April and November 2004. This period, which is considered to be the warmer period in Greece, is characterized by the development of sea-breeze over the Attica Basin. Additionally strong Northern, North-eastern winds called "The Etesians", predominate during the summer months (July-August), acting positively to the dispersion of pollutants. In this campaign, 24 days with sea-breeze development were observed, 15 days with northern winds, 6 days with southern winds while the rest of the days presented no specific wind profile. Maximum concentrations of PM(2.5), VOCs and nitrogen oxides, were detected during the days with sea-breeze, while minimum concentrations during the days with northern winds. Ozone was the only pollutant that appeared to have higher concentrations in the background site and not in the city centre, where benzene presented strong negative correlation with ozone, indicating the photochemical reaction of hydrocarbons that lead to the ozone formation. The BTX ratios were similar for both sites and wind profiles, indicating common sources for those pollutants. T/B ratio ranged in low levels, between 3-5 for site A and 2-5 for site B, suggesting vehicles emissions as the main sources of volatile compounds. Finally, the strong correlations of PM(2.5) and benzene concentrations, between the two sampling sites, indicate that both the city centre and the background site, are affected by the same sources, under common meteorological conditions (sea-breeze, northern winds).

  9. 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.

  10. Toluene-induced hearing loss in the guinea pig.

    Science.gov (United States)

    Waniusiow, Delphine; Campo, Pierre; Venet, Thomas; Cossec, Benoît; Cosnier, Frédéric; Beydon, Dominique; Rieger, Benoît; Burgart, Manuella; Ferrari, Luc; Parietti-Winkler, Cécile

    2009-10-01

    Toluene is a high-production industrial solvent, which can disrupt the auditory system in rats. However, toluene-induced hearing loss is species dependent. For instance, despite long-lasting exposures to high concentrations of aromatic solvent, no study has yet succeeded in causing convincing hearing loss in the guinea pig. This latter species can be characterized by two metabolic particularities: a high amount of hepatic cytochrome P-450s (P-450s) and a high concentration of glutathione in the cochlea. It is therefore likely that the efficiency of both the hepatic and cochlear metabolisms plays a key role in the innocuousness of the hearing of guinea pigs to exposure to solvent. The present study was carried out to test the auditory resistance to toluene in glutathione-depleted guinea pigs whose the P-450 activity was partly inhibited. To this end, animals on a low-protein diet received a general P-450 inhibitor, namely SKF525-A. Meanwhile, they were exposed to 1750 ppm toluene for 4 weeks, 5 days/week, 6 h/day. Auditory function was tested by electrocochleography and completed by histological analyses. For the first time, a significant toluene-induced hearing loss was provoked in the P-450-inhibited guinea pigs. However, the ototoxic process caused by the solvent exposure was different from that observed in the rat. Only the stria vascularis and the spiral fibers were disrupted in the apical coil of the cochlea. The protective mechanisms developed by guinea pigs are discussed in the present publication.

  11. VocVille - A Casual Social Game for Learning Vocabulary

    OpenAIRE

    Jensen, Michel

    2012-01-01

    The document introduces VocVille, a causal online game for learning vocabularies. This application is created for the author's diploma thesis of his career as a Computervisualist (computer vision) for the University of Koblenz-Landau, which he terminated as an exchange student at the University of Cádiz, in which he developed this diploma thesis.

  12. Assessment of Industrial VOC Gas-Scrubber Performance

    Energy Technology Data Exchange (ETDEWEB)

    Saito, H

    2004-02-13

    Gas scrubbers for air-pollution control of volatile organic compounds (VOC) cover a wide range of technologies. In this review, we have attempted to evaluate the single-pass scrubber destruction and removal efficiencies (DREs) for a range of gas-scrubber technologies. We have focused primarily on typical industrial DREs for the various technologies, typical problems, and any DRE-related experiential information available. The very limited literature citations found suggest significant differences between actual versus design performance in some technologies. The potentially significant role of maintenance in maintaining DREs was also investigated for those technologies. An in-depth portrayal of the entire gas scrubbing industry is elusive. Available literature sources suggest significant differences between actual versus design performance in some technologies. Lack of scrubber system maintenance can contribute to even larger variances. ''Typical'' industrial single-pass performance of commonly used VOC gas scrubbers generally ranged from {approx}80 to 99%. Imperfect solid and/or liquid particulates capture (possibly as low as 95% despite design for 99+% capture efficiency) can also lead to VOC releases. Changing the VOC composition in the gas stream without modifying scrubber equipment or operating conditions could also lead to significant deterioration in attainable destruction and removal efficiencies.

  13. EVALUATION OF SINK EFFECTS ON VOCS FROM A LATEX PAINT

    Science.gov (United States)

    The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and texanol. These oxygenated compounds rep...

  14. CASE STUDIES: LOW-VOC/HAP WOOD FURNITURE COATINGS

    Science.gov (United States)

    The report gives results of a study in which wood furniture manufacturing facilities were identified that had converted at least one of their primary coating steps to low-volatile organic compound (VOC)/hazardous Air pollutant (HAP) wood furniture coatings: high-solids, water...

  15. RESEARCH AND PRODUCT DEVELOPMENT OF LOW-VOC WOOD COATINGS

    Science.gov (United States)

    The report discusses a project, cofunded by the South Coast Air Quality Management District (SCAQMD) and the U.S. EPA, to develop a new, low volatile organic compound (VOC) wood coating. Traditional wood furniture coating technologies contain organic solvents which become air pol...

  16. Solid-phase microextraction and the human fecal VOC metabolome.

    Directory of Open Access Journals (Sweden)

    Emma Dixon

    Full Text Available The diagnostic potential and health implications of volatile organic compounds (VOCs present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.

  17. Accuracy of seven vapour intrusion algorithms for VOC in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Provoost, Jeroen; Bronders, Jan; Seuntjens, Piet [Flemish Inst. for Technological Research (VITO), Mol (Belgium); Reijnders, Lucas [Dept. of Science, Open Univ. Netherlands (OU NL), Heerlen (Netherlands); Swartjes, Frank; Lijzen, Johannes [National Inst. for Public Health and the Environment (RIVM), Bilthoven (Netherlands)

    2009-02-15

    During the last decade, soil contamination with volatile organic contaminants (VOC) received special attention because of their potential to cause indoor air problems. Moreover, research has shown that people spend 64% to 94% of there time indoors; therefore, the indoor air quality is of a primary importance for exposure to VOC. Human health risks to VOC-in cases of soil contamination-are often dominated by the exposure route 'inhalation of indoor air'. Exposure is often a result of vapour transport from the soil or groundwater to the indoor air of the building. Within human health risk assessments, a variety of algorithms are available that calculate transfer of soil gas to the indoor air. These algorithms suffer from a relatively high uncertainty due to a lack of representation of spatial and temporal variability. For such an application, these algorithms need to be further verified empirically against field observations so that they can be sufficiently reliable for regulatory purposes. This paper presents the accuracy for seven algorithms by using observed and predicted soil and indoor air concentrations from three sites, where the groundwater had been contaminated with aromatic and chlorinated VOC. (orig.)

  18. Accuracy of seven vapour intrusion algorithms for VOC in groundwater

    NARCIS (Netherlands)

    Provoost, J.; Reijnders, L.; Swartjes, F.; Bronders, J.; Seuntjens, P.; Lijzen, J.

    2009-01-01

    Background, aim and scope: During the last decade, soil contamination with volatile organic contaminants (VOC) received special attention because of their potential to cause indoor air problems. Moreover, research has shown that people spend 64% to 94% of there time indoors; therefore, the indoor ai

  19. [Volatile organic compounds (VOCs) emitted from wood furniture--estimation of emission rate by passive flux sampler].

    Science.gov (United States)

    Jinno, Hideto; Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Nishimura, Tetsuji

    2011-01-01

    The aim of this study was to evaluate aldehydes and other volatile organic compounds (VOCs) emission from furniture, which may cause hazardous influence on human being such as sick building/sick house syndrome. In this study, VOCs emitted from six kinds of wood furniture, including three set of dining tables and three beds, were analyzed by large chamber test method (JIS A 1911). Based on the emission rates of total VOCs (TVOC), the impacts on the indoor TVOC was estimated by the simulation model with volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table and one bed. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in two sets of dining tables and two beds. These results revealed that VOC emissions from wood furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative five areas of furniture unit were evaluated by passive sampling method using flux sampler and emission rate from full-sized furniture was predicted. Emission rates predicted by flux passive sampler were 10-106% (formaldehyde) and 8-141% (TVOC) of the data measured using large chamber test, respectively.

  20. Toxic Volatile Organic Compounds (VOCs in the Atmospheric Environment: Regulatory Aspects and Monitoring in Japan and Korea

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2016-09-01

    Full Text Available In the past decades, hazardous air pollutants (HAPs, so-called air toxics or toxic air pollutants, have been detected in the atmospheric air at low concentration levels, causing public concern about the adverse effect of long-term exposure to HAPs on human health. Most HAPs belong to volatile organic compounds (VOCs. More seriously, most of them are known carcinogens or probably carcinogenic to humans. The objectives of this paper were to report the regulatory aspects and environmental monitoring management of toxic VOCs designated by Japan and Korea under the Air Pollution Control Act, and the Clean Air Conservation Act, respectively. It can be found that the environmental quality standards and environmental monitoring of priority VOCs (i.e., benzene, trichloroethylene, tetrachloroethylene, and dichloromethane have been set and taken by the state and local governments of Japan since the early 2000, but not completely established in Korea. On the other hand, the significant progress in reducing the emissions of some toxic VOCs, including acrylonitrile, benzene, 1,3-butadiene, 1,2-dichloroethane, dichloromethane, chloroform, tetrachloroethylene, and trichloroethylene in Japan was also described as a case study in the brief report paper.

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

    Directory of Open Access Journals (Sweden)

    Anamai Thetkathuek

    2015-01-01

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

  2. TrgI, toluene repressed gene I, a novel gene involved in toluene-tolerance in Pseudomonas putida S12

    NARCIS (Netherlands)

    Volkers, R.J.M.; Ballerstedt, H.; Ruijssenaars, H.; Bont, J.A.M. de; Winde, J.H. de; Wery, J.

    2009-01-01

    Pseudomonas putida S12 is well known for its remarkable solvent tolerance. Transcriptomics analysis of this bacterium grown in toluene-containing chemostats revealed the differential expression of 253 genes. As expected, the genes encoding one of the major solvent tolerance mechanisms, the solvent e

  3. TrgI, toluene repressed gene I, a novel gene involved in toluene-tolerance in Pseudomonas putida S12

    NARCIS (Netherlands)

    Volkers, R.J.M.; Ballerstedt, H.; Ruijssenaars, H.; Bont, J.A.M. de; Winde, J.H. de; Wery, J.

    2009-01-01

    Pseudomonas putida S12 is well known for its remarkable solvent tolerance. Transcriptomics analysis of this bacterium grown in toluene-containing chemostats revealed the differential expression of 253 genes. As expected, the genes encoding one of the major solvent tolerance mechanisms, the solvent e

  4. TrgI, toluene repressed gene I, a novel gene involved in toluene-tolerance in Pseudomonas putida S12

    NARCIS (Netherlands)

    Volkers, R.J.M.; Ballerstedt, H.; Ruijssenaars, H.; De Bont, J.A.M.; De Winde, J.H.; Wery, J.

    2008-01-01

    Pseudomonas putida S12 is well known for its remarkable solvent tolerance. Transcriptomics analysis of this bacterium grown in toluene-containing chemostats revealed the differential expression of 253 genes. As expected, the genes encoding one of the major solvent tolerance mechanisms, the solvent e

  5. Heterogeneous Catalysts for VOC Oxidation from Red Mud and Bagasse Ash Carbon

    Science.gov (United States)

    Pande, Gaurav

    A range of VOC oxidation catalysts have been prepared in this study from agricultural and industrial waste as the starting point. The aim is to prepare catalysts with non-noble metal oxides as the active catalytic component (iron in red mud). The same active component was also supported on activated carbon obtained from unburned carbon in bagasse ash. Red mud which is an aluminum industry waste and rich in different phases of iron as oxide and hydroxide is used as the source for the catalytically active species. It is our aim to enhance the catalytic performance of red mud which though high in iron concentration has a low surface area and may not have the properties of an ideal catalyst by itself. In one of the attempts to enhance the catalytic performance, we have tried to leach red mud for which we have explored a range of leaching acids for effecting the leaching most efficiently and then precipitated the iron from the leachate as its hydroxide by precipitating with alkali solution followed by drying and calcination to give high surface area metal oxide material. Extensive surface characterization and VOC oxidation catalytic testing were performed for these solids. In a step to further enhance the catalytic activity towards oxidation, copper was introduced by taking another industrial waste from the copper tubing industry viz. the pickling acid. Copper has a more favourable redox potential making it catalytically more effective than iron. To make the mixed metal oxide, red mud leachate was mixed with the pickling acid in a pre-decided ratio before precipitating with alkali solution followed by drying and calcination as was done with the red mud leachate. The results from these experiments are encouraging. The temperature programmed reduction (TPR) of the solids show that the precipitate of red mud leachates show hydrogen uptake peak at a lower temperature than for just the calcined red mud. This could be due to the greatly enhanced surface area of the prepared

  6. 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.

  7. VOCs-Mediated Location of Olive Fly Larvae by the Braconid Parasitoid Psyttalia concolor: A Multivariate Comparison among VOC Bouquets from Three Olive Cultivars.

    Science.gov (United States)

    Giunti, Giulia; Benelli, Giovanni; Conte, Giuseppe; Mele, Marcello; Caruso, Giovanni; Gucci, Riccardo; Flamini, Guido; Canale, Angelo

    2016-01-01

    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.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    M. K. Kajos

    2015-04-01

    Full Text Available Proton transfer reaction mass spectrometry (PTR-MS and gas chromatography mass spectrometry GC-MS allow real-time measurements of various atmospheric volatile organic compounds (VOC. By taking parallel measurements in ambient conditions, two PTR-MSs and two GC-MSs were studied for their ability to measure methanol, acetaldehyde, acetone, benzene and toluene. The measurements were conducted at a rural boreal forest site in southern Finland between 13 April and 14 May 2012. This paper presents correlations and possible biases between the concentrations measured using the four instruments. This paper presents correlations and possible 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 methane, 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 arises 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.

  10. Geochemical and VOC-constraints on landfill gas age and attenuation characteristics: A case study from a waste disposal facility in Southern California.

    Science.gov (United States)

    Hagedorn, Benjamin; Kerfoot, Henry B; Verwiel, Mark; Matlock, Bruce

    2016-07-01

    In this study, a multi-tracer approach was applied to a complex, methane-impacted site in Southern California to (1) distinguish between natural gas and landfill gas (LFG)-derived methane impacts at site perimeter gas probes, (2) estimate the relative age of the LFG at these probes, and (3) document natural attenuation trends during a 3-year monitoring period. Relationships between methane and ethane values suggest that at the majority of probes, methane is from LFG and not from natural gas and that the relative contribution of LFG methane at these probes has increased over the monitoring period. To evaluate whether LFG is attenuating in the subsurface, the relative age of LFG was estimated by comparing readily degraded VOCs that are major constituents in LFG (toluene in this case) with those resistant to degradation (Freons). Time-series data trends are consistent with several probes being impacted by fresh LFG from recent releases that occurred after the update of the local LFG collection and control system (LFGCCS). Data further indicate some probes to be only affected by legacy LFG from a past release that occurred prior to the LFGCCS update and that, because of a lack of oxygen in the subsurface, had not been fully degraded. The outlined attenuation evaluation methodology is potentially applicable to other sites or even groundwater contaminants; however, the assessment is limited by the degree of homogeneity of the LFG source composition and non-LFG-derived toluene inputs to the analyzed samples.

  11. DNA stable-isotope probing of oil sands tailings pond enrichment cultures reveals different key players for toluene degradation under methanogenic and sulfidogenic conditions.

    Science.gov (United States)

    Laban, Nidal Abu; Dao, Anh; Foght, Julia

    2015-05-01

    Oil sands tailings ponds are anaerobic repositories of fluid wastes produced by extraction of bitumen from oil sands ores. Diverse indigenous microbiota biodegrade hydrocarbons (including toluene) in situ, producing methane, carbon dioxide and/or hydrogen sulfide, depending on electron acceptor availability. Stable-isotope probing of cultures enriched from tailings associated specific taxa and functional genes to (13)C6- and (12)C7-toluene degradation under methanogenic and sulfate-reducing conditions. Total DNA was subjected to isopycnic ultracentrifugation followed by gradient fraction analysis using terminal restriction fragment length polymorphism (T-RFLP) and construction of 16S rRNA, benzylsuccinate synthase (bssA) and dissimilatory sulfite reductase (dsrB) gene clone libraries. T-RFLP analysis plus sequencing and in silico digestion of cloned taxonomic and functional genes revealed that Clostridiales, particularly Desulfosporosinus (136 bp T-RF) contained bssA genes and were key toluene degraders during methanogenesis dominated by Methanosaeta. Deltaproteobacterial Desulfobulbaceae (157 bp T-RF) became dominant under sulfidogenic conditions, likely because the Desulfosporosinus T-RF 136 apparently lacks dsrB and therefore, unlike its close relatives, is presumed incapable of dissimilatory sulfate reduction. We infer incomplete oxidation of toluene by Desulfosporosinus in syntrophic association with Methanosaeta under methanogenic conditions, and complete toluene oxidation by Desulfobulbaceae during sulfate reduction. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. In situ direct sampling mass spectrometric study on formation of polycyclic aromatic hydrocarbons in toluene pyrolysis.

    Science.gov (United States)

    Shukla, Bikau; Susa, Akio; Miyoshi, Akira; Koshi, Mitsuo

    2007-08-30

    The gas-phase reaction products of toluene pyrolysis with and without acetylene addition produced in a flow tube reactor at pressures of 8.15-15.11 Torr and temperatures of 1136-1507 K with constant residence time (0.56 s) have been detected in an in situ direct sampling mass spectrometric study by using a vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry technique. Those products range from methyl radical to large polycyclic aromatic hydrocarbons (PAHs) of mass 522 amu (C(42)H(18)) including smaller species, radicals, polyynes, and PAHs, together with ethynyl, methyl, and phenyl PAHs. On the basis of observed mass spectra, the chemical kinetic mechanisms of the formation of products are discussed. Especially, acetylene is mixed with toluene to understand the effect of the hydrogen abstraction and acetylene addition (HACA) mechanism on the formation pathways of products in toluene pyrolysis. The most prominent outputs of this work are the direct detection of large PAHs and new reaction pathways for the formation of PAHs with the major role of cyclopenta-fused radicals. The basis of this new reaction route is the appearance of different sequences of mass spectra that well explain the major role of aromatic radicals mainly cyclopenta fused radicals of PAHs resulting from their corresponding methyl PAHs, with active participation of c-C(5)H(5), C(6)H(5), C(6)H(5)CH(2) ,and C(9)H(7) in the formation of large PAHs. The role of the HACA only seemed important for the formation of stable condensed PAHs from unstable primary PAHs with zigzag structure (having triple fusing sites) in one step by ring growth with two carbon atoms.

  13. Flow, Transport and Biodegradation of Toluene During Bioventing

    Institute of Scientific and Technical Information of China (English)

    隋红; 徐世民; 李鑫钢; 姜斌; 黄国强

    2004-01-01

    Bioventing is conducted on one-dimensional soil columns. A numerical model is developed for simulating the mass exchange, adivective and dispersive transport and biodegradation of toluene. The model parameters are estimated independently through laboratory batch experiments, or from literature. Simulations are found to provide reasonable agreement with experimental data. Experimental results show that toluene removal due to biodegradiation is more important at the later stage. The total cleanup time when NAPL (non-aqueous phase liquid) phase exists was twice more than that without NAPL. Sensitivity analysis of parameters suggests that model predictions are mainly dependent on mass transfer coefficient and microbial parameters, such as the half-saturation coefficient and maximum specific substrate utilization rate.

  14. Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Palacio, Luz A. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Velasquez, Juliana; Echavarria, Adriana [Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Faro, Arnaldo [Departamento de Fisicoquimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Ilha do Fundao, CT bloco A, Rio de Janeiro (Brazil); Ramoa Ribeiro, F. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ribeiro, M. Filipa, E-mail: filipa.ribeiro@ist.utl.pt [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2010-05-15

    Two trimetallic ZnCuAl and MnCuAl hydrotalcites have been successfully synthesized by a co-precipitation method. The manganese based material was identified as a new hydrotalcite phase. Both lamellar precursors were calcined at 450 and 600 deg. C and the resulting catalysts were tested on reaction of total oxidation of toluene. The solids were characterized by X-ray diffraction, thermal analysis, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, N{sub 2} adsorption and H{sub 2} temperature-programmed reduction. It was found that ZnCuAl materials are composed of copper and zinc oxides supported on alumina; while MnCuAl ones comprise basically spinel phases, which were not completely identified. The catalytic behavior of the calcined samples showed that Mn hydrotalcite calcined at 450 deg. C exhibited the best catalytic performance that corresponds to 100% toluene conversion into CO{sub 2} at about 300 deg. C.

  15. Toluene metabolism during exposure to varying concentrations combined with exercise

    DEFF Research Database (Denmark)

    Bælum, Jesper; Døssing, M; Hansen, S H

    1987-01-01

    between the exposure schedules. In Study B, 32 males and 39 females aged between 31 and 50 years were exposed once to either clean air, constant or varying concentrations of toluene. Background excretion rate of HA was 0.97 +/- 0.75 mg/min (1.25 +/- 1.05 g/g creatinine) and rose to 3.74 +/- 1.40 mg/min (3.......90 +/- 1.85 g/g cr) during the last 3 h of exposure to 100 ppm toluene. The corresponding figures for O-cr were 0.05 +/- 0.05 micrograms/min (0.08 +/- 0.14 mg/g cr), and 2.04 +/- 0.84 micrograms/min (2.05 +/- 1.18 mg/g cr). The individual creatinine excretion rate was considerably influenced by sex, body...

  16. Toluene removal in a biofilm reactor for waste gas treatment

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1997-01-01

    A lab-scale trickling filter for treatment of toluene-containing waste gas was investigated. The filter performance was investigated for various loads of toluene. Two levels of the gas flow were examined, 322 m d(-1) and 707 m d(-1). The gas inlet concentrations were varied in the range from 0.6 ...... showed an almost even biofilm growth over the filter height, which was in accordance with a constant liquid concentration throughout the column. (C) 1997 IAWQ. Published by Elsevier Science Ltd....... and the surface removal rates estimated by parameter fitting corresponded to previously observed values. The effect of the gas flow on the mass transfer coefficient and the biological removal rate may be explained by different flow patterns of the gas and the liquid phases. A characterisation of the biofilm...

  17. Use of On-Site GC/MS Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs

    Science.gov (United States)

    2013-11-01

    71DE Engineered Fluid Toluene Some paints and adhesives SprayPAK Enamel , Minwax Wood Finish Xylenes Adhesives , paints, gasoline Bonide Tree Sprays and...ay be less ef adhesives . H products con ion include ces of the e to its abil f indoor air h stakehold y interprete ncern, a fou samples ra rounds...Bonder, Radio Shack Anti Static Foaming Cleaner Chloroform Dry cleaned clothes, fire extinguishers, adhesive remover, chlorinated drinking water

  18. Bathtub refinisher's lung: an unusual response to toluene diisocyanate.

    Science.gov (United States)

    Fink, J N; Schlueter, D P

    1978-11-01

    Immunologic and inhalation challenge studies were performed on a patient engaged in bathtub refinishing who developed systemic and respiratory symptoms suggestive of hypersensitivity pneumonitis temporally related to his occupation. The refinishing process used a catalyst containing toluene diisocyanate, and all clinical features of the disorder were reproduced by challenge. No immunologic mechanism could be identified. A change of occupation resulted in complete relief of symptoms.

  19. Eco friendly nitration of toluene using modified zirconia

    Directory of Open Access Journals (Sweden)

    K.R. Sunaja Devi

    2013-03-01

    Full Text Available Nitration of toluene has been studied in the liquid phase over a series of modified zirconia catalysts.  Zirconia, zirconia- ceria (Zr0.98Ce0.02O2, sulfated zirconia and sulfated zirconia- ceria were synthesised by co precipitation method and were characterised by X-ray diffraction, BET surface area, Infra red spectroscopy analysis (FTIR, Thermogravimetric analysis (TGA, Scanning Electron Microscopy (SEM and Energy Dispersive X ray analysis (EDAX. The acidity of the prepared catalysts was determined by FTIR pyridine adsorption study. X-ray diffraction studies reveal that the catalysts prepared mainly consist of tetragonal phase with the crystallite size in the nano range and the tetragonal phase of zirconia is stabilized by the addition of ceria. The modified zirconia samples have higher surface area and exhibits uniform pore size distribution aggregated by zirconia nanoparticles. The onset of sulfate decomposition was observed around 723 K for sulfated samples. The catalytic performance was determined for the liquid phase nitration of toluene to ortho-, meta- and para- nitro toluene. The effect of reaction temperature, concentration of nitric acid, catalyst reusability and reaction time was also investigated. © 2013 BCREC UNDIP. All rights reservedReceived: 20th November 2012; Revised: 8th December 2012; Accepted: 7th January 2013[How to Cite: K. R. S. Devi, S. Jayashree, (2013. Eco friendly nitration of toluene using modified zirconia. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 205-214. (doi:10.9767/bcrec.7.3.4154.205-214][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4154.205-214 ] View in  |

  20. Comparison of measurement methods for benzene and toluene

    Science.gov (United States)

    Wideqvist, U.; Vesely, V.; Johansson, C.; Potter, A.; Brorström-Lundén, E.; Sjöberg, K.; Jonsson, T.

    Diffusive sampling and active (pumped) sampling (tubes filled with Tenax TA or Carbopack B) were compared with an automatic BTX instrument (Chrompack, GC/FID) for measurements of benzene and toluene. The measurements were made during differing pollution levels and different weather conditions at a roof-top site and in a densely trafficked street canyon in Stockholm, Sweden. The BTX instrument was used as the reference method for comparison with the other methods. Considering all data the Perkin-Elmer diffusive samplers, containing Tenax TA and assuming a constant uptake rate of 0.406 cm3 min-1, showed about 30% higher benzene values compared to the BTX instrument. This discrepancy may be explained by a dose-dependent uptake rate with higher uptake rates at lower dose as suggested by laboratory experiments presented in the literature. After correction by applying the relationship between uptake rate and dose as suggested by Roche et al. (Atmos. Environ. 33 (1999) 1905), the two methods agreed almost perfectly. For toluene there was much better agreement between the two methods. No sign of a dose-dependent uptake could be seen. The mean concentrations and 95% confidence intervals of all toluene measurements (67 values) were (10.80±1.6) μg m -3 for diffusive sampling and (11.3±1.6) μg m -3 for the BTX instrument, respectively. The overall ratio between the concentrations obtained using diffusive sampling and the BTX instrument was 0.91±0.07 (95% confidence interval). Tenax TA was found to be equal to Carbopack B for measuring benzene and toluene in this concentration range, although it has been proposed not to be optimal for benzene. There was also good agreement between the active samplers and the BTX instrument.

  1. Molecular characterization of a toluene-degrading methanogenic consortium.

    Science.gov (United States)

    Ficker, M; Krastel, K; Orlicky, S; Edwards, E

    1999-12-01

    A toluene-degrading methanogenic consortium enriched from creosote-contaminated aquifer material was maintained on toluene as the sole carbon and energy source for 10 years. The species in the consortium were characterized by using a molecular approach. Total genomic DNA was isolated, and 16S rRNA genes were amplified by using PCR performed with kingdom-specific primers that were specific for 16S rRNA genes from either members of the kingdom Bacteria or members of the kingdom Archaea. A total of 90 eubacterial clones and 75 archaeal clones were grouped by performing a restriction fragment length polymorphism (RFLP) analysis. Six eubacterial sequences and two archaeal sequences were found in the greatest abundance (in six or more clones) based on the RFLP analysis. The relative abundance of each putative species was estimated by using fluorescent in situ hybridization (FISH), and the presence of putative species was determined qualitatively by performing slot blot hybridization with consortium DNA. Both archaeal species and two of the six eubacterial species were detected in the DNA and FISH hybridization experiments. A phylogenetic analysis of these four dominant organisms suggested that the two archaeal species are related to the genera Methanosaeta and Methanospirillum. One of the eubacterial species is related to the genus Desulfotomaculum, while the other is not related to any previously described genus. By elimination, we propose that the last organism probably initiates the attack on toluene.

  2. Ignition studies of n-heptane/iso-octane/toluene blends

    KAUST Repository

    Javed, Tamour

    2016-07-09

    Ignition delay times of four ternary blends of n-heptane/iso-octane/toluene, referred to as Toluene Primary Reference Fuels (TPRFs), have been measured in a high-pressure shock tube and in a rapid compression machine. The TPRFs were formulated to match the research octane number (RON) and motor octane number (MON) of two high-octane gasolines and two prospective low-octane naphtha fuels. The experiments were carried out over a wide range of temperatures (650–1250 K), at pressures of 10, 20 and 40 bar, and at equivalence ratios of 0.5 and 1.0. It was observed that the ignition delay times of these TPRFs exhibit negligible octane dependence at high temperatures (T > 1000 K), weak octane dependence at low temperatures (T < 700 K), and strong octane dependence in the negative temperature coefficient (NTC) regime. A detailed chemical kinetic model was used to simulate and interpret the measured data. It was shown that the kinetic model requires general improvements to better predict low-temperature conditions and particularly requires improvements for high sensitivity (high toluene concentration) TPRF blends. These datasets will serve as important benchmark for future gasoline surrogate mechanism development and validation. © 2016 The Combustion Institute

  3. 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

  4. Subjective symptoms due to solvent mixtures, dioxin, and toluene: impact of exposure versus personality factors.

    Science.gov (United States)

    Seeber, A; Demes, P; Golka, K; Kiesswetter, E; Schäper, M; van Thriel, C; Zupanic, M

    2000-10-01

    In this study, we analyse the impact of personality factors on the frequency of self-reported symptoms for workers under different exposure conditions. Reported symptoms may depend on the level and type of exposure, as well as on personality factors such as trait anxiety of the worker or his general sensitivity with regard to the environment. The employed data stems from three studies: The first study contains information of 60 workers who suspected to be exposed to polychlorined dibenzodioxins and dibenzofuranes (Lifetime Weighted Average Exposure, LWAE, as an index for contact with the substances). The second study concerns 40 workers who are exposed to different concentrations of solvent mixtures in paint manufacturing (LWAE of total hydrocarbons about 10 ppm). The third study includes repeated measurements of two subgroups of workers from rotogravure printing plants who are exposed to different concentrations of toluene: a "high" exposure group (n = 129, LWAE about 46 ppm, current exposure 25 ppm) and a "low" exposure group (n = 96, LWAE for toluene about 9 ppm, current exposure 3 ppm). Trait anxiety, environmental sensitivity, and self-reported symptoms are measured by validated questionnaires and age as well as verbal intelligence are controlled. To determine the effect of the individual characteristics and the different exposures on self-reported symptoms, frequency analyses and variance analyses are conducted and linear models are fitted. For all analyses, trait anxiety explains the highest share of the variance. If there is no effect of the exposure on the reported symptoms (dioxin and low-level toluene study), trait anxiety seems to have a larger explanatory power in comparison with those studies where the exposure has an effect on the reported symptoms (solvent-mixture and high-level toluene study). Neurotoxicological risk analysis has to account for the detected dependence of self-reported symptoms on personality traits: assessments for elevated

  5. PERVAPORATION SEPARATION FOR TOLUENE/n-HEPTANE MIXTURE BY POLYIMIDE MEMBRANES CONTAINING FLUORINE

    Institute of Scientific and Technical Information of China (English)

    Hong Ye; Ji-ding Li; Yang-zheng Lin; Jian Chen; Cui-xian Chen

    2008-01-01

    Five kinds of polyimides were synthesized using five dianhydrides (including 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride (BPADA), 3,3',4,4'-diphenyisulfone-tetracarboxylic dianhydride (DSDA), 4,4'(hexafluoroisopropylidene)-diphthalic anhydride (6FDA),1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA),and 4,4'-oxydiphthlic dianhydride (ODPA)) and 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane (BDAF) via the twostep method that included polyaddition to form the polyamic acid and subsequent chemical imidization at ambient temperature.The structures of polyimides were characterized by FTIR and NMR.The thermal properties were characterized by DSC and TGA.All five kinds of polyimides showed good thermal properties and solubility in organic solvents such as DMF,DMAc,NMP and THF at room temperature.The pervaporation (PV) experiments of polyimides for toluene/n-heptane mixture were carried out,and all the polyimides showed selective permeation towards toluene.The fluxes of 6FDA-BDAF,DSDA-BDAF,HQDPA-BDAF and ODPA-BDAF at 80℃ were 1.08,0.96,1.77 and 0.10 kg-μm/(m2.h),and the separation factors were 5.44,1.64,1.28 and 11.44,respectively.The increasing feed temperature resulted in higher flux and lower separation factor of the 6FDA-BDAF membrane.

  6. A complex chemical kinetic mechanism for the oxidation of gasoline surrogate fuels: n heptane, iso octane and toluene - Mechanism development and validation

    CERN Document Server

    Da Cruz, A Pires; Anderlohr, Jörg; Bounaceur, Roda; Battin-Leclerc, Frédérique

    2009-01-01

    The development and validation against experimental results of a new gasoline surrogate complex kinetic mechanism is presented in this paper. The surrogate fuel is a ternary mixture of n heptane, iso octane and toluene. The full three components mechanism is based on existing n heptane/iso octane (gasoline PRF) and toluene mechanisms which were modified and coupled for the purpose of this work. Mechanism results are compared against available experimental data from the literature. Simulations with the PRF plus toluene mechanism show that its behavior is in agreement with experimental results for most of the tested settings. These include a wide variety of thermodynamic conditions and fuel proportions in experimental configurations such as HCCI engine experiments, rapid compression machines, a shock tube and a jet stirred reactor.

  7. Ensurdecimento vocálico em Zo’é

    Directory of Open Access Journals (Sweden)

    Ana Suelly Arruda Câmara Cabral

    2012-11-01

    Full Text Available Neste trabalho apresentamos uma descrição do fenômeno deensurdecimento vocálico na língua Zo’é (Tupi-Guarani. Sãoapresentadas ainda hipóteses acerca das restrições sincrônicas ativasno condicionamento deste fenômeno, além de uma hipótese acercada origem histórica do mesmo.

  8. Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

    KAUST Repository

    Alabi, Wahab

    2012-07-01

    A kinetic study of toluene alkylation with methanol was performed over pure HZSM-5, mordenite/ZSM-5 (hybrid of mordenite and HZSM-5), and ZM13 (composite mixture of HZSM-5 and MCM-41 at pH 13). Experimental runs were conducted using a batch fluidized bed reactor at temperatures of 300, 350 and 400 °C and reaction times of 3, 5, 7, 10, 13, 15 and 20. s. The rate of toluene methylation and toluene disproportionation were studied on the three catalysts (toluene alkylation is usually accompanied by toluene disproportionation on acid catalyst). Based on the results obtained, a simplified power law kinetic model consisting of three reactions was developed to estimate the activation energies of toluene methylation and disproportionation simultaneously. Coke formation on catalysts was accounted for using both reaction time and reactant conversion decay functions. All parameters were estimated based on quasi-steady state approximation. Estimated kinetic parameters were in good agreement with experimental results. The order of alkylation ability of the catalysts was found to be ZM13 > HZSM-5 > mordenite/ZSM-5, while the reverse is for toluene disproportionation (mordenite/ZSM-5 > HZSM-5 > ZM13). Thus, alkylation of toluene is most favorable on ZM13 due to combined effect of mesoporosity induced through its synthetic route and acid content. Toluene/MeOH molar ratio of 1:1 was most suitable for toluene alkylation reaction. © 2012 Elsevier B.V.

  9. Effects of Oxygen Transfer Limitation and Kinetic Control on Biomimetic Catalytic Oxidation of Toluene

    Institute of Scientific and Technical Information of China (English)

    罗伟平; 刘大为; 孙俊; 邓伟; 盛文兵; 刘强; 郭灿城

    2014-01-01

    Under oxygen transfer limitation and kinetic control, liquid-phase catalytic oxidation of toluene over metalloporphyrin was studied. An improved technique of measuring dissolved oxygen levels for gas-liquid reaction at the elevated temperature and pressure was used to take the sequential data in the oxidation of toluene catalyzed by metalloporphyrin. By this technique the corresponding control step of toluene oxidation could be obtained by varying reaction conditions. When the partial pressure of oxygen in the feed is lower than or equal to 0.070 MPa at 463 K, the oxidation of toluene would be controlled by oxygen transfer, otherwise the reaction would be controlled by kinetics. The effects of both oxygen transfer and kinetic control on the toluene conversion and the selectivity of benzaldehyde and benzyl alcohol in biomimetic catalytic oxidation of toluene were systematically investigated. Three conclusions have been made from the experimental results. Firstly, under the oxygen transfer limitation the toluene conversion is lower than that under kinetic control at the same oxidation conditions. Secondly, under the oxygen transfer limitation the total selectivity of benzaldehyde and benzyl alcohol is lower than that under kinetic control with the same conversion of toluene. Finally, under the kinetics control the oxidation rate of toluene is zero-order with respect to oxygen. The experimental results are identical with the biomimetic catalytic mechanism of toluene oxidation over metalloporphyrins.

  10. Protective effects of quercetine on the neuronal injury in frontal cortex after chronic toluene exposure.

    Science.gov (United States)

    Kanter, Mehmet

    2013-08-01

    The aim of this study was designed to evaluate the possible protective effects of quercetine (QE) on the neuronal injury in the frontal cortex after chronic toluene exposure in rats. The rats were randomly allotted into one of the three experimental groups, namely, groups A (control), B (toluene treated) and C (toluene-treated with QE), where each group contains 10 animals. Control group received 1 ml of normal saline solution, and toluene treatment was performed by the inhalation of 3000 ppm toluene in an 8-h/day and 6-day/week order for 12 weeks. The rats in QE-treated group was given QE (15 mg/kg body weight) once a day intraperitoneally for 12 weeks, starting just after toluene exposure. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of neurodegeneration in the frontal cortex after chronic toluene exposure in rats by QE treatment have been reported. In this study, the morphology of neurons in the QE treatment group was well protected. Chronic toluene exposure caused severe degenerative changes, shrunken cytoplasm and extensively dark picnotic nuclei in neurons of the frontal cortex. We conclude that QE therapy causes morphologic improvement in neurodegeneration of frontal cortex after chronic toluene exposure in rats. We believe that further preclinical research into the utility of QE may indicate its usefulness as a potential treatment on neurodegeneration after chronic toluene exposure in rats.

  11. Light dependency of VOC emissions from selected Mediterranean plant species

    Science.gov (United States)

    Owen, S. M.; Harley, P.; Guenther, A.; Hewitt, C. N.

    The light, temperature and stomatal conductance dependencies of volatile organic compound (VOC) emissions from ten plant species commonly found in the Mediterranean region were studied using a fully controlled leaf cuvette in the laboratory. At standard conditions of temperature and light (30°C and 1000 μmol m -2 s -1 PAR), low emitting species ( Arbutus unedo, Pinus halepensis, Cistus incanus, Cistus salvifolius, Rosmarinus officinalis and Thymus vulgaris) emitted between 0.1 and 5.0 μg (C) (total VOCs) g -1 dw h -1, a medium emitter ( Pinus pinea) emitted between 5 and 10 μg (C) g -1 dw h -1 and high emitters ( Cistus monspeliensis, Lavendula stoechas and Quercus sp.) emitted more than 10 μg (C) g -1 dw h -1. VOC emissions from all of the plant species investigated showed some degree of light dependency, which was distinguishable from temperature dependency. Emissions of all compounds from Quercus sp. were light dependent. Ocimene was one of several monoterpene compounds emitted by P. pinea and was strongly correlated to light. Only a fraction of monoterpene emissions from C. incanus exhibited apparent weak light dependency but emissions from this plant species were strongly correlated to temperature. Data presented here are consistent with past studies, which show that emissions are independent of stomatal conductance. These results may allow more accurate predictions of monoterpene emission fluxes from the Mediterranean region to be made.

  12. A mass transfer model for VOC emission from silage

    Science.gov (United States)

    Hafner, Sasha D.; Montes, Felipe; Rotz, C. Alan

    2012-07-01

    Silage has been shown to be an important source of emissions of volatile organic compounds (VOCs), which contribute to the formation of ground-level ozone. Measurements have shown that environmental conditions and silage properties strongly influence emission rates, making it difficult to assess the contribution of silage in VOC emission inventories. In this work, we present an analytical convection-diffusion-dispersion model for predicting emission of VOCs from silage. It was necessary to incorporate empirical relationships from wind tunnel trials for the response of mass transfer parameters to surface air velocity and silage porosity. The resulting model was able to accurately predict the effect of temperature on ethanol emission in wind tunnel trials, but it over-predicted alcohol and aldehyde emission measured using a mass balance approach from corn silage samples outdoors and within barns. Mass balance results confirmed that emission is related to gas-phase porosity, but the response to air speed was not clear, which was contrary to wind tunnel results. Mass balance results indicate that alcohol emission from loose silage on farms may approach 50% of the initial mass over six hours, while relative losses of acetaldehyde will be greater.

  13. Monomer and dimer radical cations of benzene, toluene, and naphthalene.

    Science.gov (United States)

    Das, Tomi Nath

    2009-06-11

    Pulse radiolytic generation of monomeric and dimeric cations of benzene, toluene, and naphthalene in aqueous acid media at room temperature and their spectrophotometric characterization is discussed. Results presented include measurements of each aromatic's solubility in H(2)O-H(2)SO(4) and H(2)O-HClO(4) media over the acidity range pH 1 to H(0) -7.0, facile oxidative generation, and real-time identification of appropriate cationic transients with respective lambda(max) (nm) and epsilon (M(-1) cm(-1)) values measured as follows: C(6)H(6)(*+) (443, 1145 +/- 75), C(6)H(5)CH(3)(*+) (428, 1230 +/- 90), C(10)H(8)(*+) (381, 3650 +/- 225, and 687, 2210 +/- 160), (C(6)H(6))(2)(*+) (860, 2835 +/- 235), (C(6)H(5)CH(3))(2)(*+) (950, 1685 +/- 155), and (C(10)H(8))(2)(*+) (1040, 4170 +/- 320). Kinetic measurements reveal the respective formation rates of monomeric cations to be near-diffusion controlled, while the forward rate values for the dimeric species generation are marginally slower. The proton activity corrected pK(a) values are found to remain between -2.6 and -1.3 for the ArH(*+) species (C(6)H(6)(*+) most acidic, C(10)H(8)(*+) least acidic), while the pK(a) values of (ArH)(2)(*+) species vary from -5.0 to -3.0 ((C(6)H(6))(2)(*+) most acidic, (C(10)H(8))(2)(*+) least acidic). In H(0) -5 in aqueous H(2)SO(4), the respective stabilization energy of (C(6)H(6))(2)(*+), (C(6)H(5)CH(3))(2)(*+), and (C(10)H(8))(2)(*+) is estimated to be 16.6, 15.0, and 13.7 kcal mol(-1). Thus, the aqueous acid solution emerges as an alternative medium for typical radical-cationic studies, while offering compatibility for the deprotonated radical characterization near neutral pH.

  14. Application of Glycyrrhiza glabra Root as a Novel Adsorbent in the Removal of Toluene Vapors: Equilibrium, Kinetic, and Thermodynamic Study

    Directory of Open Access Journals (Sweden)

    Fazel Mohammadi-Moghadam

    2013-01-01

    Full Text Available The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants.

  15. Application of Glycyrrhiza glabra root as a novel adsorbent in the removal of toluene vapors: equilibrium, kinetic, and thermodynamic study.

    Science.gov (United States)

    Mohammadi-Moghadam, Fazel; Amin, Mohammad Mehdi; Khiadani Hajian, Mehdi; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Hatamipour, Mohammad Sadegh

    2013-01-01

    The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR) as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R) isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants.

  16. Application of Glycyrrhiza glabra Root as a Novel Adsorbent in the Removal of Toluene Vapors: Equilibrium, Kinetic, and Thermodynamic Study

    Science.gov (United States)

    Mohammadi-Moghadam, Fazel; Amin, Mohammad Mehdi; Khiadani (Hajian), Mehdi; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Hatamipour, Mohammad Sadegh

    2013-01-01

    The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR) as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R) isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants. PMID:23554821

  17. Electrochemical peroxidation of PCBs and VOCs in superfund site water and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Scrudato, R.J.; Chiarenzelli, J.R. [SUNY, Oswego, NY (United States)

    1996-12-31

    An electrochemical peroxidation (ECP) process has been developed and used to degrade polychlorinated biphenyls (PCB) and volatile organic compounds (VOC)-contaminated water, sludge, and sediments at a New York State Federal and State Superfund Site. The process involves passing an oscillating low-amperage (<10 amps) current through steel electrodes immersed in an acidified water or sediment slurry into which hydrogen peroxide (<1,000 ppm) is added. The generated free radicals attack organic compounds, including organo-metallic complexes and refractory compounds including PCBs. PCB degradation ranged from about 30% to 80% in experiments involving Federal Superfund Site sediments; total PCBs were reduced by {approximately}97% to 68%, respectively, in water and slurry collected from a State Superfund subsurface storage tank. VOC bench-scale experiments involved chloroethane, 1,1-dichloroethane, dichloromethane, 1,1,1-trichloroethane, and acetone and after a 3-min ECP treatment, degradation ranged from >94% to about 99.9%. Results indicate the ECP is a viable process to degrade organic contaminants in water and sediment suspensions. Because the treated water suspensions are acidified, select trace metal sorbed to the particulates is solubilized and therefore can be segregated from the particulates, offering a process that simultaneously degrades organic contaminants and separates trace metals. 19 refs., 1 fig., 4 tabs.

  18. The Amazonian Floodplains, an ecotype with challenging questions on volatile organic compound (VOC) emissions

    Science.gov (United States)

    Kesselmeier, J.

    2012-12-01

    Volatile organic compound (VOC) emissions are affected by a variety of biotic and abiotic factors such as light intensity, temperature, CO2 and drought. Another factor usually overlooked but very important for the tropical rainforest in Amazonia is regular flooding. According to recent estimates, the total Amazonian floodplain area easily ranges up to 700,000 km^2, including whitewater river floodplains (várzea) blackwater regions (igapó) and further clearwater regions. Regarding the total Amazonian wetlands the area sums up to more than 2.000.000 km^2, i.e. 30% of Amazonia. To survive the flooding periods causing anoxic conditions for the root system of up to several months, vegetation has developed several morphological, anatomical and physiological strategies. One is to switch over the root metabolism to fermentation, thus producing ethanol as one of the main products. Ethanol is a toxic metabolite which is transported into the leaves by the transpiration stream. From there it can either be directly emitted into the atmosphere, or can be re-metabolized to acetaldehyde and/or acetate. All of these compounds are volatile enough to be partly released into the atmosphere. We observed emissions of ethanol, acetaldehyde and acetic acid under root anoxia. Furthermore, plant stress induced by flooding also affected leaf primary physiological processes as well as other VOC emissions such as the release of isoprenoids and other volatiles. For example, Hevea spruceana could be identified as a monoterpene emitting tree species behaving differently upon anoxia depending on the origin, with increasing emissions of the species from igapó and decreasing with the corresponding species from várzea. Contrasting such short term inundations, studies of VOC emissions under long term conditions (2-3 months) did not confirm the ethanol/acetaldehyde emissions, whereas emissions of other VOC species decreased considerably. These results demonstrate that the transfer of our knowledge

  19. Experiments in the EMRP project KEY-VOCs: Adsorption/desorption effects of VOCs in different tubing materials and preparation and analysis of a zero gas

    Science.gov (United States)

    Englert, Jennifer; Claude, Anja; Kubistin, Dagmar; Tensing, Erasmus; Michl, Katja; Plass-Duelmer, Christian

    2017-04-01

    Atmospheric chemistry and composition are influenced by volatile organic compounds (VOCs) emitted from natural and anthropogenic sources. Due to their toxicity and their crucial role in ozone and aerosol formation VOCs impact air quality and climate change and high quality observations are demanded. The European Metrology Research Programme (EMRP) project KEY-VOCs has targeted the improvement of VOC measurement capabilities with the focus on VOCs relevant for indoor air as well as for air quality and climate monitoring programmes. One major uncertainty is the influence of surface effects of the measurement devices. By developing a test system the adsorption/desorption effects of certain VOCs can be systematically examined. Different tubing materials e.g. stainless steel and PFA were analysed with the oxygenated VOC methanol and results of these experiments will be presented. In air quality monitoring very low levels of VOCs have to be measured. Purified air or nitrogen is widely used as a zero gas to characterize measurement systems and procedures as well as for instrument calibration. A high quality zero gas is an important contributor to the quality of the measurements and generally achieved by using state-of-the-art purification technologies. The efficiency of several air purifiers was assessed and the results have been analysed.

  20. Site S-7 VOC Transport modeling for the Vadose Zone Monitoring System (VZMS), McClellan AFB - 1999 Semi-Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Doughty, Christine; Oldenburg, Curtis M.; James, April L.

    1999-06-15

    Enhanced data analysis is continuing for the Vadose Zone Monitoring System (VZMS) installed at site S-7 in IC 34 at McClellan AFB. Air temperatures along with data from the four highest levels of thermistors in VZMS-A and B are used with an analytical solution for the heat conduction equation to show that heat transfer in the shallow vadose zone at S-7 is conduction-dominated. This analysis is extended to reveal that stiace temperature, i.e., the temperature of the concrete slab at S-7, is significantly higher in summer than the surrounding air temperature. These high temperatures in the shallow vadose zone can lead to increased volatilization of VOCS. Seasonal temperature reversals can cause upward buoyant gas flow in the uppermost 30 feet of the vadose zone in the winter. Data on gas-phase VOC concentrations in VZMS-A and B show highest concentrations in the shallow subsurface, low concentrations between depths of 30-70 feet, and slightly higher concentrations near the water table. Modeling VOC flow and transport subject to the constraints of data collected by the VZMS requires extension of the one-dimensional site-representative model used previously. Conceptual models broadly consistent with these data include (1) a diffusion-only model; (2) a preferential flow model; or (3) two- and three-dimensional flow models where the VOC plume undergoes lateral migration. Simulations of VOC transport suggest that there are VOCS at depths shallower than 6 feet, that significant NAPL is unlikely to be present, and that a source of VOCS may be provided by lateral flow in the gravel layer between two concrete layers present at the site. The conceptual models upon which VOC transport modeling is based require further development and testing. Prior Vapour-T modeling results for the S-7 site based on cis-1,2-DCE concentrations in well SS7SB08 are not substantiated by VZMS data, but these data are localized whereas VapourT results are generalized for the S-7 site as a whole

  1. Enhanced biofilm production by a toluene-degrading Rhodococcus observed after exposure to perfluoroalkyl acids.

    Science.gov (United States)

    Weathers, Tess S; Higgins, Christopher P; Sharp, Jonathan O

    2015-05-05

    This study focuses on interactions between aerobic soil-derived hydrocarbon degrading bacteria and a suite of perfluorocarboxylic acids and perfluoroalkylsulfonates that are found in aqueous film-forming foams used for fire suppression. No effect on toluene degradation rate or induction time was observed when active cells of Rhodococcus jostii strain RHA1 were exposed to toluene and a mixture of perfluoroalkyl acids (PFAAs) including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) at concentrations near the upper bounds of groundwater relevance (11 PFAAs at 10 mg/L each). However, exposure to aqueous PFAA concentrations above 2 mg/L (each) was associated with enhanced aggregation of bacterial cells and significant increases in extracellular polymeric substance production. Flocculation was only observed during exponential growth and not elicited when PFAAs were added to resting incubations; analogous flocculation was also observed in soil enrichments. Aggregation was accompanied by 2- to 3-fold upregulation of stress-associated genes, sigF3 and prmA, during growth of this Rhodococcus in the presence of PFAAs. These results suggest that biological responses, such as microbial stress and biofilm formation, could be more prominent than suppression of co-contaminant biodegradation in subsurface locations where poly- and perfluoroalkyl substances occur with hydrocarbon fuels.

  2. Research Progress onPhotochemical Behaviorsof Ambient Volatile Organic Compounds (VOCs)%环境空气中挥发性有机物(V OCs)光化学行为的研究进展

    Institute of Scientific and Technical Information of China (English)

    苏雷燕; 赵明; 李岩; 陈长虹

    2013-01-01

    Volatile organic compounds(VOCs)is an important precursor of tropospheric ozone and secondary organic aerosol ,whose pollution problem has attracted wide attention of scholars at home and abroad .Usual-ly ,OH radical loss rate and the ozone formation potential (OFP) are applied to assess the chemical reactivity of VOCs .The key reactive species arexylene ,toluene ,ethylbenzene and C2-C5 alkene .Fractional aerosol co-efficients (FAC) and the ratio of organic carbon and element carbon (OC/EC) are used to estimate the po-tential formation of secondary organic aerosols (SOA) .The SOA precursors contain terpene and aromatics . The ratio ofVOCs to NOx (VOCs/NOx) is used to analyze the relation between O3 and NOx ,VOCs qualita-tively ,which is abhorrent .Based on the researches of atmospheric VOCs photochemical behavior ,this article reviews the studies of chemical reactivity of VOCs ,potential formation of SOA and the relation between O3 and NOx ,VOCs so as to provide a scientific basis for VOCs ,particles and O3 pollutioncontrol .%指出了挥发性有机物(VOCs)是对流层臭氧(O3)和二次有机气溶胶(SOA )等二次污染的重要前体物,其污染问题已经引起了国内外学者的广泛关注。通常采用羟基(OH)消耗速率和臭氧生成潜势(OFP)表征VOCs的大气反应活性,VOCs的关键活性组分主要有芳香烃中的二甲苯、甲苯、乙苯以及C2到C5的烯烃;采用FAC估算法和有机碳/元素碳(OC/EC)比值法来估算 VOCs对SOA生成的贡献,SOA的主要前体物有萜烯和芳香烃;采用VOCs/NOX 比值定性分析大气中O3浓度与NOX 和VOCs的关系,国内外城市O3的生成对VOCs和NOX 浓度的变化敏感性不一致。基于国内外大气中挥发性有机物(VOCs )光化学行为的研究动态,阐述了环境空气中VOCs的大气反应活性、二次有机气溶胶(SOA )的生成贡献以及与NOX 、O3的关系,为VOCs、细粒子以及O3污染的控制提供科学依据。

  3. 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.

  4. The function of a toluene-degrading bacterial community in a waste gas trickling filter

    DEFF Research Database (Denmark)

    Pedersen, A.R.; Arvin, E.

    1999-01-01

    oligonucleotide 16S ribosomal RNA probe targeting the toluene-degrading species Pseudomonas putida, and by computer simulations (AQUASIM) of the biofilm growth based on a food web model. Biofilms were taken from a lab-scale trickling filter for treatment of toluene-polluted air. The biofilm growth......The function of a community of toluene-degrading bacteria in a biofilm system was investigated with regard to growth and toluene degradation in order to investigate substrate interactions in the community. This was done by the combination of experimental observations using a specific...... and the activity of P. putida, a representative of the toluene-degrading species in the biofilm which have been described previously (Pedersen et al., 1997) were simulated. The simulation indicated that the volume fraction of the toluene degraders in the biofilm decreased from 12% to only 2% (11% of dry weight...

  5. Elucidating the Stereochemistry of Enzymatic Benzylsuccinate Synthesis with Chirally Labeled Toluene.

    Science.gov (United States)

    Seyhan, Deniz; Friedrich, Peter; Szaleniec, Maciej; Hilberg, Markus; Buckel, Wolfgang; Golding, Bernard T; Heider, Johann

    2016-09-12

    Benzylsuccinate synthase is a glycyl radical enzyme that initiates anaerobic toluene metabolism by adding fumarate to the methyl group of toluene to yield (R)-benzylsuccinate. To investigate whether the reaction occurs with retention or inversion of configuration at the methyl group of toluene, we synthesized both enantiomers of chiral toluene with all three H isotopes in their methyl groups. The chiral toluenes were converted into benzylsuccinates preferentially containing (2) H and (3) H at their benzylic C atoms, owing to a kinetic isotope effect favoring hydrogen abstraction from the methyl groups. The configuration of the products was analyzed by enzymatic CoA-thioester synthesis and stereospecific oxidation using enzymes involved in benzylsuccinate degradation. Assessment of the configurations of the benzylsuccinate isomers based on loss or retention of tritium showed that inversion of configuration at the methyl group occurs when the chiral toluenes react with fumarate.

  6. Physical properties of (propyl propanoate + hexane + toluene) at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Freire, S. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain)]. E-mail: sfreire@udc.es; Segade, L. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain); Cabeza, O. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain); Jimenez, E. [Departamento de Fisica, Facultade de Ciencias, Universidade da Coruna, 15071 A Coruna (Spain)

    2007-04-15

    The aim of this paper is to report experimental densities, excess molar enthalpies and refractive indexes of the ternary system (propyl propanoate + hexane + toluene) and of the corresponding binary mixtures (propyl propanoate + toluene) and (hexane + toluene) at the temperature 298.15 K and atmospheric pressure, over the whole composition range. Also, the excess molar volumes and the changes in the refractive index on mixing have been calculated from the measured data for all mixtures.

  7. Toluene metabolism in isolated rat hepatocytes: effects of in vivo pretreatment with acetone and phenobarbital

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Kielland, A.; Ripel, A. (National Inst. of Forensic Toxicology, Oslo (Norway))

    1993-02-01

    Hepatocytes isolated from control, acetone- and phenobarbital-pretreated rats were used to study the metabolic conversion of toluene to benzyl alcohol, benzaldehyde, benzoic acid and hippuric acid at low (<100 [mu]M) and high (100-500 [mu]M) toluene concentrations. The baseline formation rates of toluene metabolites (benzyl alcohol, benzoic acid and hippuric acid) were 2.9[+-]1.7 and 10.0[+-]2.3 nmol/mg cell protein/60 min at low and high toluene concentrations, respectively. In vivo pretreatment of rats with acetone and phenobarbital increased the formation of metabolites: at low toluene concentrations 3- and 5-fold, respectively; at high toluene concentrations no significant increase (acetone) and 8-fold increase (phenobarbital). Apparent inhibition by ethanol, 7 and 60 mM, was most prominent at low toluene concentrations: 63% and 69%, respectively, in control cells; 84% and 91% in acetone-pretreated cells, and 32% (not significant) and 51% in phenobarbital-pretreated cells. Ethanol also caused accumulation of benzyl alcohol. The apparent inhibition by isoniazid was similar to that of ethanol at low toluene concentrations. Control and acetone-pretreated cells were apparently resistant towards metyrapone; the decrease was 49% and 64% in phenobarbital-pretreated cells at low and high toluene concentrations, respectively. In these cells, the decrease in presence of combined ethanol and metyrapone was 95% (low toluene concentrations). 4-Methylpyrazole decreased metabolite formation extensively in all groups. Benzaldehyde was only found in the presence of an aldehyde dehydrogenase inhibitor. Increased ratio benzoic/hippuric acid was observed at high toluene concentrations. These results demonstrate that toluene oxidation may be studied by product formation in isolated hepatocytes. However, the influence of various enzymes in the overall metabolism could not be ascertained due to lack of inhibitor specificity. (orig.).

  8. Measurements and modeling to quantify emissions of methane and VOCs from shale gas operations: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Presto, Albert A [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-06-30

    The objectives of the project were to determine the leakage rates of methane and ozone-forming Volatile Organic Compounds (VOCs) and the emission rates of air toxics from Marcellus shale gas activities. Methane emissions in the Marcellus Shale region were differentiated between “newer” sources associated with shale gas development and “older” sources associated with coal or conventional natural gas exploration. This project conducted measurements of methane and VOC emissions from both shale and non-shale natural gas resources. The initial scope of the project was the Marcellus Shale basin, and measurements were conducted in both the western wet gas regions (southwest PA and WV) and eastern dry gas region (northeast PA) of the basin. During this project, we obtained additional funding from other agencies to expand the scope of measurements to include additional basins. The data from both the Marcellus and other basins were combined to construct a national analysis of methane emissions from oil & gas production activities.

  9. Probing Ternary Solvent Effect in High V(oc) Polymer Solar Cells Using Advanced AFM Techniques.

    Science.gov (United States)

    Li, Chao; Ding, Yi; Soliman, Mikhael; Lorenzo, Josie; Dhasmana, Nitesh; Chantharasupawong, Panit; Ievlev, Anton V; Gesquiere, Andre J; Tetard, Laurene; Thomas, Jayan

    2016-02-01

    This work describes a simple method to develop a high V(oc) low band gap PSCs. In addition, two new atomic force microscopy (AFM)-based nanoscale characterization techniques to study the surface morphology and physical properties of the structured active layer are introduced. With the help of ternary solvent processing of the active layer and C60 buffer layer, a bulk heterojunction PSC with V(oc) more than 0.9 V and conversion efficiency 7.5% is developed. In order to understand the fundamental properties of the materials ruling the performance of the PSCs tested, AFM-based nanoscale characterization techniques including Pulsed-Force-Mode AFM (PFM-AFM) and Mode-Synthesizing AFM (MSAFM) are introduced. Interestingly, MSAFM exhibits high sensitivity for direct visualization of the donor-acceptor phases in the active layer of the PSCs. Finally, conductive-AFM (cAFM) studies reveal local variations in conductivity in the donor and acceptor phases as well as a significant increase in photocurrent in the PTB7:ICBA sample obtained with the ternary solvent processing.

  10. 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.)

  11. Genotoxicity of intermittent co-exposure to benzene and toluene in male CD-1 mice.

    Science.gov (United States)

    Wetmore, Barbara A; Struve, Melanie F; Gao, Pu; Sharma, Sheela; Allison, Neil; Roberts, Kay C; Letinski, Daniel J; Nicolich, Mark J; Bird, Michael G; Dorman, David C

    2008-06-17

    Benzene is an important industrial chemical. At certain levels, benzene has been found to produce aplastic anemia, pancytopenia, myeloblastic anemia and genotoxic effects in humans. Metabolism by cytochrome P450 monooxygenases and myeloperoxidase to hydroquinone, phenol, and other metabolites contributes to benzene toxicity. Other xenobiotic substrates for cytochrome P450 can alter benzene metabolism. At high concentrations, toluene has been shown to inhibit benzene metabolism and benzene-induced toxicities. The present study investigated the genotoxicity of exposure to benzene and toluene at lower and intermittent co-exposures. Mice were exposed via whole-body inhalation for 6h/day for 8 days (over a 15-day time period) to air, 50 ppm benzene, 100 ppm toluene, 50 ppm benzene and 50 ppm toluene, or 50 ppm benzene and 100 ppm toluene. Mice exposed to 50 ppm benzene exhibited an increased frequency (2.4-fold) of micronucleated polychromatic erythrocytes (PCE) and increased levels of urinary metabolites (t,t-muconic acid, hydroquinone, and s-phenylmercapturic acid) vs. air-exposed controls. Benzene co-exposure with 100 ppm toluene resulted in similar urinary metabolite levels but a 3.7-fold increase in frequency of micronucleated PCE. Benzene co-exposure with 50 ppm toluene resulted in a similar elevation of micronuclei frequency as with 100 ppm toluene which did not differ significantly from 50 ppm benzene exposure alone. Both co-exposures - 50 ppm benzene with 50 or 100 ppm toluene - resulted in significantly elevated CYP2E1 activities that did not occur following benzene or toluene exposure alone. Whole blood glutathione (GSH) levels were similarly decreased following exposure to 50 ppm benzene and/or 100 ppm toluene, while co-exposure to 50 ppm benzene and 100 ppm toluene significantly decreased GSSG levels and increased the GSH/GSSG ratio. The higher frequency of micronucleated PCE following benzene and toluene co-exposure when compared with mice exposed to

  12. Biodegradation of toluene using Candida tropicalis immobilized on polymer matrices in fluidized bed bioreactors.

    Science.gov (United States)

    Song, JiHyeon; Namgung, HyeongKyu; Ahmed, Zubair

    2012-11-30

    A yeast strain, Candida tropicalis, was whole-cell-immobilized on polymer matrices of polyethylene glycol (PEG) and polyethylene glycol/activated carbon/alginate (PACA). The polymer matrices were used as fluidized materials in bubble-column bioreactors for the biodegradation of toluene. Simultaneously, another bubble-column bioreactor using granular activated carbon (GAC) and a conventional compost biofilter were operated for comparison. In the compost biofilter, the toluene removal efficiency gradually deteriorated due to the limitation of microbial activity. The toluene removal in the GAC bioreactor was relatively high because of an increase of toluene mass transfer. However, low toluene removal efficiencies were observed in the PEG bioreactor, presumably because the synthetic polymer alone was not suitable for yeast cell immobilization. In the PACA bioreactor, toluene removal was found to be greater than 95% overall. The CO(2) yield coefficient calculated at the highest toluene loading condition for the PACA bioreactor was found to be higher than those observed in the other bioreactors. Furthermore, almost complete elimination capacities were observed in the PACA bioreactor at short-term toluene loading up to 180 g/m(3)/h. In conclusion, the immobilization of C. tropicalis in the PACA matrix resulted in enhanced toluene biodegradation because of the increases of both mass transfer and microbial activity.

  13. Degradation of off-gas toluene in continuous pyrite Fenton system.

    Science.gov (United States)

    Choi, Kyunghoon; Bae, Sungjun; Lee, Woojin

    2014-09-15

    Degradation of off-gas toluene from a toluene reservoir and a soil vapor extraction (SVE) process was investigated in a continuous pyrite Fenton system. The removal of off-gas toluene from the toluene reservoir was >95% by 8h in the pyrite Fenton system, while it was ∼97 % by 3h in classic Fenton system and then rapidly decreased to initial level by 8h. Continuous consumption of low Fe(II) concentration dissolved from pyrite surface (0.05-0.11 mM) was observed in the pyrite Fenton system, which can lead to the effective and successful removal of the gas-phase toluene due to stable production of OH radical (OH). Inhibitor and spectroscopic test results showed that OH was a dominant radical that degraded gas-phase toluene during the reaction. Off-gas toluene from the SVE process was removed by 96% in the pyrite Fenton system, and remnant toluene from rebounding effect was treated by 99%. Main transformation products from toluene oxidation were benzoic acid (31.4%) and CO2 (38.8%) at 4h, while traces of benzyl alcohol (1.3%) and benzaldehyde (0.7%) were observed. Maximum operation time of continuous pyrite Fenton system was estimated to be 56-61 d and its optimal operation time achieving emission standard was 28.9 d. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Absorption of gaseous toluene in aqueous solutions of some kinds of fluorocarbon surfactant.

    Science.gov (United States)

    Xiao, Xiao; Yan, Bo; Fu, Jiamo; Xiao, Xianming

    2015-01-01

    A self-designed device was applied to treat a simulated exhaust gas loaded with toluene by aqueous solutions of five kinds of fluorocarbon surfactant (FS-3100, FS-22, FSN-100, FSO-100 and FSG) under the controlled laboratory conditions. The simulated exhaust gas is generated by a mixture of clean air and toluene vapor, and its toluene concentration can be controlled by changing the volume ratio of the inlet air to the vapor. Two mass transfer methods: liquid-liquid transfer and gas-liquid transfer, were compared for their toluene saturation capacities of these absorbent solutions, and it was found that more toluene was dissolved by the liquid-liquid transfer than by the gas-liquid transfer. According to the saturation capacities of these absorbent solutions and their Henry's Constants, FSO-100 is the best absorbent to treat the simulated exhaust gas and was selected for further experiments. The FSO-100 absorbent solution with a concentration of 0.1 % shows an efficient absorption to the simulated exhaust gas, with a toluene saturation capacity of 4.2 mg/g. Heating distillation (90- 95 oC) is highly efficient to recover toluene from the FSO-100 absorbent solution as well as regenerate it. A toluene recovery of about 85 % was achieved. The regenerated absorption solution can keep its initial toluene absorption capacity during the reuse.

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

    Directory of Open Access Journals (Sweden)

    S. J. Sjostedt

    2011-06-01

    Full Text Available 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.

  16. Toluene removal from sandy soils via in situ technologies with an emphasis on factors influencing soil vapor extraction.

    Science.gov (United States)

    Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

    2014-01-01

    The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

  17. Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2014-01-01

    Full Text Available The integration of bioventing (BV and soil vapor extraction (SVE appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5% of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

  18. Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

    Science.gov (United States)

    Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

    2014-01-01

    The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater. PMID:24587723

  19. 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...... 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...... 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...

  20. Purge and trap method to determine alpha factors of VOC liquid-phase mass transfer coefficients

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A theoretical approach and laboratory practice of determining the alpha factors of volatile organic compound (VOC) liquid-phase mass transfer coefficients are present in this study.Using Purge Trap Concentrator, VOC spiked water samples are purged by high-purity nitrogen in the laboratory, the VOC liquid-phase mass transfer rate constants under the laboratory conditions are then obtained by observing the variation of VOCs purged out of the water with the purge time.The alpha factors of VOC liquid-phase mass transfer coefficients are calculated as the ratios of the liquid-phase mass transfer rate constants in real water samples to their counterparts in pure water under the same experimental conditions. This direct and fast approach is easy to control in the laboratory, and would benefit mutual comparison among researchers, so might be useful for thestudy of VOC mass transfer across the liquid-gas interface.

  1. 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.

  2. [Study on the chemical compositions of VOCs emitted by cooking oils based on GC-MS].

    Science.gov (United States)

    He, Wan-Qing; Nie, Lei; Tian, Gang; Li, Jing; Shao, Xia; Wang, Min-Yan

    2013-12-01

    Volatile organic compounds (VOCs) are key precursors of ozone and secondary organic aerosols in air, and the differences in the compositions of VOCs lead to their different contribution to atmospheric reaction. Cooking oil fume is one of the important sources of atmospheric VOCs, and its chemical compositions are distinct under different conditions of oil types, food types, cooking methods and heating temperatures etc. In this study, the production of cooking oil fume was simulated by heating typical pure vegetable oils (peanut oil, sunflower oil, soybean oil, olive oil and blend oil) at different temperatures in beakers to investigate the chemical compositions of VOCs. The emitted VOCs were sampled with a Tenax adsorption tube and analyzed using GC-MS after thermal desorption. According to spectral library search and map analysis, using area normalized semi-quantitative method, preliminary qualitative and quantitative tests were conducted for the specific components of VOCs under different conditions.

  3. Active site dynamics of toluene hydroxylation by cytochrome P-450

    Energy Technology Data Exchange (ETDEWEB)

    Hanzlik, R.P.; Kahhiing John Ling (Univ. of Kansas, Lawrence (United States))

    1990-06-22

    Rat liver cytochrome P-450 hydroxylates toluene to benzyl alcohol plus o-, m-, and p-cresol. Deuterated toluenes were incubated under saturating conditions with liver microsomes from phenobarbital-pretreated rats, and product yields and ratios were measured. Stepwise deuteration of the methyl leads to stepwise decreases in the alcohol/cresol ratio without changing the cresol isomer ratios. Extensive deuterium retention in the benzyl alcohols from PhCH{sub 2}D and PhCHD{sub 2} suggests there is a large intrinsic isotope effect for benzylic hydroxylation. After replacement of the third benzylic H by D, the drop in the alcohol/cresol ratio was particularly acute, suggsting that metabolic switching from D to H within the methyl group was easier than switching from the methyl to the ring. Comparison of the alcohol/cresol ratio for PhCH{sub 3} vs PhCD{sub 3} indicated a net isotope effect of 6.9 for benzylic hydroxylation. From product yield data for PhCH{sub 3} and PhCD{sub 3}, {sup D}V for benzyl alcohol formation is only 1.92, whereas {sup D}V for total product formation is 0.67 (i.e., inverse). From competitive incubations of PhCH{sub 3}/PhCD{sub 3} mixtures {sup D}(V/K) isotope effects on benzyl alcohol formation and total product formation (3.6 and 1.23, respectively) are greatly reduced, implying strong commitment to catalysis. In contrast, {sup D}(V/K) for the alcohol/cresol ratio is 6.3, indicating that the majority of the intrinsic isotope effect is expressed through metabolic switching. Overall, these data are consistent with reversible formation of a complex between toluene and the active oxygen form of cytochrome P-450, which rearranges internally and reacts to form products faster than it dissociates back to release substrate.

  4. 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

  5. Tricarbonylbis(tricyclohexylphosphine-κPruthenium(0 toluene solvate

    Directory of Open Access Journals (Sweden)

    Andreas Nader

    2008-11-01

    Full Text Available The title compound, [Ru(C18H33P2(CO3]·C7H8, shows a distorted trigonal-bipyramdial coordination around the central Ru atom, with the two phosphine ligands occupying the axial positions. Two toluene molecules per asymmetric unit with site-occupation factors of 0.5 are observed. One of them forces two of the CO ligands to enclose a wider C—Ru—C bond angle [127.5 (3°] than in the solvent-free crystal structure of [Ru(PCy32(CO3] (Cy is cyclohexyl.

  6. Desorption of toluene from modified clays using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Carneiro D. G. P.

    2004-01-01

    Full Text Available The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained using the second-order model. This study makes possible the scale-up of the desorption process for regeneration of solid matrices using supercritical fluids.

  7. 基于微气体传感器阵列和神经网络的VOCs的辨别%Recognizing VOCs with Micro-GAS Sensor Array and Neural Network

    Institute of Scientific and Technical Information of China (English)

    吕品; 唐祯安; 魏广芬

    2007-01-01

    A micro-gas sensor array was composed of the six tin oxide thin film gas sensors with Au, Cu, or Pt metal catalyst. The sensing properties of sensors to the volatile organic compounds (VOCs) were evaluated. VOCs mean VOCsmixture and formaldehyde (HCHO) in the paper, while the VOCsmixture is the mixtures of 10 ppm toluene, 1 ppm acetone, 5 ppm α-pinene and 10 ppm ethanol. And a multilayer neural network with an error backpropagation (BP) learning algorithm was implemented to recognize the low concentration VOCsmixture and HCHO. The results demonstrated that the micro-sensor array, plus multilayer neural network, was very effective to recognize not only low concentration sin