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1

Volatile fatty acids as organic carbon sources in denitrification  

Microsoft Academic Search

We have evaluated the possibilities of waste water denitrification using volatile fatty acids (VFA) as the sole carbon and electron source in an activated sludge culture continuously fed with a mixture of acetate, propionate, butyrate and valerate. All the VFA were biodegraded in denitrification conditions by a mixed adapted bacterial population with 5 predominant different bacterial strains (Ochrobactrum anthropi, Moraxella

S. Fass; V. Ganaye; V. Urbain; J. Manem; J. C. Block

1994-01-01

2

Volatile fatty acid cycling in organic-rich marine sediments  

NASA Astrophysics Data System (ADS)

Volatile fatty acid (VFA) apparent turnover rates were determined by measuring whole sediment VFA concentrations and the corresponding reaction rate constants. The following ranges of VFA concentrations were measured in Cape Lookout Bight, N.C. sediments (?mole·l s-1): acetate 54-660, propionate 1-24, butyrate <0.5-22, iso-butyrate <0.5-6. Apparent turnover rates measured over a one-year period ranged from 18-600 ?mole·l s-1·h -1 for acetate and 0.7-7 ?mole·l s-1·h -1 for the carboxyl carbon of propionate. Methane production was observed only with acetate and only in sulfatedepleted sediments; total acetate turnover attained approximately the same maximum value in both sulfate-reducing and sulfate-depleted sediments. Apparent turnover rates for acetate and propionate appeared to be controlled by similar factors: in sulfate-reducing (surface) sediments the turnover rates were stimulated by autumn storm-mediated deposition/resuspension events; in deeper sulfate-depleted sediments the turnover rates followed changes in the ambient temperature. Changes in VFA poolsizes were proportionally much larger than changes in corresponding rate constants. The ratio of CO 2 to CH 4 produced from acetate vs. depth suggested that non-methanogenic bacteria accounted for 60% of the acetate turnover in sulfate-depleted sediments. VFA concentrations were much lower in N.C. continental slope mud than in Cape Lookout sediments; acetate was the only VFA detectable throughout the top 40 cm of the slope sediments. The estimated production rate of CO 2 from acetate decreased rapidly with depth. The surface rate was approximately 20 times less than that measured at similar temperatures in sulfate-reducing Cape Lookout sediments.

Sansone, Francis J.; Martens, Christopher S.

1982-09-01

3

Exposure to Wood Dust, Resin Acids, and Volatile Organic Compounds During Production of Wood Pellets  

Microsoft Academic Search

The main aim of this study was to investigate exposure to airborne substances that are potentially harmful to health during the production of wood pellets, including wood dust, monoterpenes, and resin acids, and as an indicator of diesel exhaust nitrogen dioxide. In addition, area measurements were taken to assess background exposure levels of these substances, volatile organic compounds (VOCs), and

Katja Hagström; Sara Axelsson; Helena Arvidsson; Ing-Liss Bryngelsson; Cecilia Lundholm; Kåre Eriksson

2008-01-01

4

VOC (VOLATILE ORGANIC COMPOUND EMISSION FACTORS FOR THE NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSION INVENTORY  

EPA Science Inventory

The report gives results of the generation of emission factors for volatile organic compound (VOC) emissions for a number of source classification categories (SCCs), as part of the National Acid Precipitation Assessment Program (NAPAP). Each SCC represents a process or function t...

5

Determination of Organic Acids and Volatile Flavor Substances in Kefir during Fermentation  

Microsoft Academic Search

The production of organic acids and volatile flavor components was measured during kefir starter culture fermentation. Samples were collected at 0, 5, 10, 15, and 22 h of fermentation (final pH=4.6). Samples were analyzed for orotic, citric, pyruvic, uric, lactic, acetic, butyric, propionic and hippuric acids by HPLC. Acetaldehyde, ethanol, acetoin and diacetyl production were monitored using GC equipped with

Z. B. Güzel-Seydim; A. C. Seydim; A. K. Greene; A. B. Bodine

2000-01-01

6

Simultaneous determination of non-volatile, semi-volatile, and volatile organic acids in tobacco by SIM-Scan mode GC-MS.  

PubMed

A method for simultaneous determination of seven nonvolatile organic acids (NVOAs), five semivolatile organic acids (SVOAs), and twelve volatile organic acids (VOAs) in tobacco by synchronous SIM (Selected Ion Monitoring)-scan mode GC-MS was developed. The collection of NVOAs and SVOAs data was performed in full-scan mode, and that of VOAs data was carried out with SIM. Recoveries of NVOAs and SVOAs varied from 90.0 to 103.0%, and RSDs were less than 4.0%; recoveries of VOAs ranged from 89.5 to 99.3%, and their RSDs were less than 3.0%. Twelve tobacco samples were analyzed by the described method, and the results show that the method is applicable for the simultaneous determination of VOAs, NVOAs, and SVOAs in tobacco. PMID:18307165

Wang, Baoxing; Yang, Shihua; Chen, Guohui; Wu, Yi; Hou, Ying; Xu, Guowang

2008-03-01

7

Volatile tritiated organic acids in stack effluents and in air surrounding contaminated materials  

NASA Astrophysics Data System (ADS)

A small fraction of the tritium released into the atmosphere from tritium-handling or solid waste storage facilities was shown to be in the form of volatile organic acids. The same compounds were also found, but at a much higher proportion, in the tritium evolved at room temperature from highly contaminated materials placed under air atmospheres. This might be due to the oxidation and labeling of hydrocarbon(s) by mechanisms that are presumably of a radiolytic nature. The new forms could have an impact on operational requirements and waste management strategies within a tritium facility and a fusion reactor hall. Further data are needed to assess the related doses.

Belot, Y.; Camus, H.; Marini, T.; Raviart, S.

1993-06-01

8

Volatile Organic Compounds Derived from 2-Keto-Acid Decarboxylase in Microcystis aeruginosa  

PubMed Central

Volatile organic compounds (VOCs), 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol, were detected together with ?-cyclocitral from the cyanobacterium Microcystis aeruginosa NIES-843. These alcohols were optimally produced after 35 d of culture, during which nitrate nitrogen in the cultured broth became exhausted. Additionally, these alcohols were definitely produced using the 2-keto-acid decarboxylase (MaKDC) in Microcystis strains. These results suggested that these VOCs from Microcystis are significant for their lifecycle, because these compounds are not produced by any other genus of cyanobacteria. This is the first report of 2-keto-acid decarboxylase producing 3-methyl-1-butanol and 2-phenylethanol by an oxygenic photosynthetic microorganism.

Hasegawa, Masateru; Nishizawa, Akito; Tsuji, Kiyomi; Kimura, Shigenobu; Harada, Ken-ichi

2012-01-01

9

Anaerobic fermentation of organic solid wastes: volatile fatty acid production and separation.  

PubMed

Anaerobic fermentation of organic municipal solid waste was investigated using a leach-bed reactor (LBR) to assess the volatile fatty acid (VFA) production efficiency. The leachate recycle rate in the LBR affected the VFA composition of the leachate. A six-fold increase in the recycle rate resulted in an increase of the acetic acid fraction of leachate from 24.7 to 43.0%. The separation of VFAs via leachate replacement resulted in higher total VFA production. VFA separation from synthetic VFA mix and leachate of a fermented organic waste was assessed via a counter-current flow polytetrafluoroethylene (PTFE) membrane contactor. Acetic and propionic acid permeation fluxes of 13.12 and 14.21 g/m(2).h were obtained at low feed pH values when a synthetic VFA mix was used as a feed solution. The highest selectivity was obtained for caproic acid compared to that of other VFAs when synthetic VFA mix or leachate was used as a feed solution. High pH values and the presence of suspended solids in the leachate adversely affected the permeation rate. PMID:24845331

Yesil, H; Tugtas, A E; Bayrakdar, A; Calli, B

2014-01-01

10

SIMPLIFIED VOLATILE ORGANICS SAMPLER  

EPA Science Inventory

The report describes the results of a task supporting EPA in its efforts to license hazardous waste incinerators. The study provided a design for a simplified sampling system for medium levels of volatile organic compounds (VOCs). Most of the study involved evaluation of sorbents...

11

Residential wood burning in an Alpine valley as a source for oxygenated volatile organic compounds, hydrocarbons and organic acids  

NASA Astrophysics Data System (ADS)

During a 3-week campaign in November/December 2005, 21 selected oxygenated volatile organic compounds (OVOCs), 19 non-methane hydrocarbons (NMHCs) and 11 low molecular weight organic acids were measured in Roveredo, a village in the Mesolcina valley in Southern Switzerland. In this region, the majority of the houses are heated with wood and the particulate matter is dominated by residential wood burning emissions. Markers in the aerosol mass spectra and carbon monoxide (CO) were used as indicators of domestic wood combustion while nitrogen oxides (NO x) were used as tracers for traffic emissions. The main source for most of the OVOCs, NMHCs and acids in this valley was assessed to be residential wood burning, except for trimethylbenzene (TMB), methylbutenol (MBO) and isopropanol. Comparisons for the NMHCs and OVOCs were made with measurements in Zürich, the largest city in Switzerland. These comparisons indicate that especially methanol, 1,3-butadiene, acrolein, methacrolein, methylacetate and methyl vinyl ketone (MVK) were strongly enhanced in Roveredo due to residential wood burning. The carcinogenic substance 1,3-butadiene shows higher concentrations in Roveredo than in Zürich, while benzene concentrations are similar at both locations. We provide a compilation of the VOC/CO ratios of the domestic wood burning dominated VOCs at Roveredo and a comparison to previously published emission ratios from wood stove studies.

Gaeggeler, Kathrin; Prevot, Andre S. H.; Dommen, Josef; Legreid, Geir; Reimann, Stefan; Baltensperger, Urs

12

Emissions of acetic acid and other volatile organic compounds from different species of solid wood  

Microsoft Academic Search

The emission of volatile organic compounds (VOC) from wood and wood products are important in evaluating the impact on the\\u000a indoor environment from different materials. The results from analyses of emissions from nine different wood species are presented\\u000a in this article. The measurements were made with Field and Laboratory Emission Cell (FLEC) and with Head-Space (HS) analyses\\u000a and the results

M. Risholm-Sundman; M. Lundgren; E. Vestin; P. Herder

1998-01-01

13

Regeneration of lactic and succinic acid-laden basic sorbents by leaching with a volatile base in an organic solvent  

SciTech Connect

Leaching with an organic solution of a volatile base was explored as a method of regenerating tertiary amine and pyridyl sorbents. Experimental data are presented that show that regeneration efficiency correlated with the nonaqueous basicity of the regenerant as measured by the Gutmann donicity scale. Essentially complete regeneration of lactic acid-laden Dowex MWA-1 was achieved when 8--10 mol of trimethylamine were present for every mole of adsorbed acid; adequate (>70%) regeneration was obtained at a 2:1 molar ratio. The resulting trimethylamine-lactic acid complex can be thermally decomposed fully when trimethylamine is employed in an organic solvent instead of in water. A likely cause of the incomplete thermal decomposition of trimethylammonium lactate in previous, water-based systems is the aqueous environment in which the decomposition was performed.

Husson, S.M.; King, C.J. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering] [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering; [Lawrence Berkeley National Lab., CA (United States)

1998-08-01

14

Fatty acid composition, oxidation status and volatile organic compounds in "Colonnata" lard from Large White or Cinta Senese pigs as affected by curing time.  

PubMed

The aim of the present paper was to evaluate the fatty acid composition, lipolysis, lipid oxidation and volatile organic compounds (VOCs) in Colonnata lard from Large White (LW) or Cinta Senese (CS) pigs during one-year of curing. CS lard contained higher amounts of unsaturated fatty acids than that from LW, due to the different rearing and feeding systems. Despite higher lipolysis in CS backfat during the curing period, the rate of fatty acid and cholesterol oxidation was higher in LW. The amount of cholesterol oxidation products (COPs) and thiobarbituric acid reactive substances (TBARs) significantly decreased after 3 months of curing, regardless of the type of lard. VOCs composition of lard was affected by curing time, but not by breed. While volatile fatty acid oxidation products (mainly aldehydes) were present at the beginning of curing, subsequently other volatile compounds (such as sulphur compounds and terpenes) that derived from ingredients used for lard production, increased in the samples. PMID:24769871

Serra, A; Buccioni, A; Rodriguez-Estrada, M T; Conte, G; Cappucci, A; Mele, M

2014-08-01

15

Optimization of microwave-assisted solvent extraction for volatile organic acids in tobacco and its comparison with conventional extraction methods.  

PubMed

In the present study, a new method using microwave-assisted solvent extraction (MASE) technique followed directly GC analysis was developed for the extraction of volatile organic acids (VOAs) in tobacco. The MASE conditions (heating time, volume of extracting solvent and extraction temperature) were optimized by means of an orthogonal array design (OAD) procedure. The results suggested that extractant, temperature and heating time were statistically the most significant factors. The extracts were directly analyzed with capillary GC operating in splitless-injection mode on an Agilent HP-FFAP capillary column. Under optimum operating conditions, MASE showed significantly better recoveries than those obtained by the conventional extraction method (ultrasonic and reflux extraction), ranging from 90.6% to 103.2%. In addition, a drastic reduction of the extraction time (20 min versus 4h) and solvent consumption (20 mL versus 100 mL) was achieved with an outstanding reproducibility (CV < or =5%). PMID:17723732

Zhu, Xiaolan; Su, Qingde; Cai, Jibao; Yang, Jun

2006-10-01

16

Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.  

PubMed

Nutrient composition and organoleptic properties of milk can be influenced by cow diets. The objective of this study was to evaluate the forage type effects on volatile organic compounds, fatty acid (FA) profile, and organoleptic properties of milk. Timothy grass was fed as hay, pasture, or silage during a period of 27 d to a group of 21 cows in a complete block design based on days in milk. Each cow also received 7.2 kg/d of a concentrate mix to meet their nutrient requirements. Forage dry matter intake averaged 13.9 kg/d and was not different among treatments. Milk yield was higher for cows fed pasture, intermediate for cows fed silage, and lowest for cows fed hay. However, milk fat content was higher for cows fed hay and silage, compared with cows fed pasture. As a result, fat-corrected milk and fat yield were not different among treatments. Increasing the supply of dietary cis-9,cis-12 18:2 (linoleic acid) and cis-9,cis-12,cis-15 18:3 (?-linolenic acid) when feeding pasture enhanced the concentration of these 2 essential FA in milk fat compared with feeding hay or silage. Moreover, the ratio of 16:0 (palmitic acid) to cis-9 18:1 (oleic acid), which is closely related to the melting properties of milk fat, was lower in milk from cows on pasture than in milk from cows fed hay or silage. Cows fed hay produced milk with higher levels of several free FA and ?-lactones, but less pentanal and 1-pentanol. More dimethyl sulfone and toluene were found in milk of cows on pasture. Cows fed silage produced milk with higher levels of acetone, 2-butanone, and ?-pinene. Results from a sensory evaluation showed that panelists could not detect a difference in flavor between milk from cows fed hay compared with silage. However, a significant number of assessors perceived a difference between milk from cows fed hay compared with milk from cows fed pasture. In a sensory ranking test, the percentage of assessors ranking for the intensity of total (raw milk, fresh milk, and farm milk), sweet (empyreumatic, vanilla, caramel, and sugar), and grassy (grass, leafy vegetable, and plant) flavors was higher for milk from cows fed pasture compared with hay and silage. Using timothy hay, pasture, or silage harvested at a similar stage of development, the current study shows that the taste of milk is affected by the forage type fed to cows. More research is, however, needed to establish a link between the sensory attributes of milk and the observed changes in volatile organic compounds and FA profile. PMID:24035021

Villeneuve, M-P; Lebeuf, Y; Gervais, R; Tremblay, G F; Vuillemard, J C; Fortin, J; Chouinard, P Y

2013-11-01

17

VOLATILIZATION OF ORGANIC POLLUTANTS FROM WATER  

EPA Science Inventory

The volatilization of organic environmental contaminants from water bodies to the atmosphere was investigated. The general aim was to elucidate the factors that control the volatilization process and develop predictive methods for calculating volatilization rates for various comp...

18

Inorganic salts interact with organic di-acids in sub-micron particles to form material with low hygroscopicity and volatility  

NASA Astrophysics Data System (ADS)

Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. Here we show that inorganic-organic component interactions typically not considered in atmospheric models may strongly affect aerosol volatility and hygroscopicity. In particular, bi-dentate binding of di-carboxylic acids (DCA) to soluble inorganic ions can lead to very strongly bound metal-organic complexes with largely undetermined hygroscopicity and volatility. These reactions profoundly impact particle hygroscopicity, transforming hygroscopic components into irreversibly non-hygroscopic material. While the hygroscopicities of pure salts, DCA, and DCA salts are known, the hygroscopicity of internal mixtures of hygroscopic salts and DCA, as they are typically found in the atmosphere, has not been fully characterized. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the CCN activation diameter for particles with divalent salts (e.g. CaCl2) and relatively small particle mass fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O:C are capable of forming low volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles with very low viscosity.

Drozd, G.; Woo, J.; Häkkinen, S. A. K.; Nenes, A.; McNeill, V. F.

2013-11-01

19

Volatile Organic Compounds (VOCs)  

MedlinePLUS

... carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions. Organic ... day. The hazards include exposure to chemicals from glues, polishes, removers, and other salon products; muscle strains ...

20

Low volatile organic compound paints  

Microsoft Academic Search

Increasingly stringent air emission standards in various states has dictated the elimination of engineering finishes which are derived from high volatile organic compound (VOC) paint chemistries. In July 1989, Allied-Signal, Inc., Kansas City Division, Kansas City, Missouri, voluntarily closed its paint facility, due to non-compliance with local air emission standards. The following details the materials selection and evaluations which led

1991-01-01

21

Influence of microflora on texture and contents of amino acids, organic acids, and volatiles in semi-hard cheese made with DL-starter and propionibacteria.  

PubMed

The microflora of semi-hard cheese made with DL-starter and propionic acid bacteria (PAB) is quite complex, and we investigated the influence of its variation on texture and contents of organic acids, free amino acids, and volatile compounds. Variation in the microflora within the normal range for the cheese variety Grevé was obtained by using a PAB culture in combination with different DL-starters and making the cheeses at 2 dairy plants with different time and temperature profiles during ripening. Propionic acid bacteria dominated the microflora during ripening after a warm room period at levels of log 8 to log 9 cfu/g, which was about 1 log unit higher than the total number of starter bacteria and about 2 log units higher than the number of nonstarter lactic acid bacteria. Eye formation was observed during the warm room period and further ripening (at 8 to 10°C). The amounts of acetate, propionate, total content of free amino acids, 2-propanol, and ethyl propionate in the ripened cheeses were related to the number of PAB. A decrease in the relative content of Asp and Lys and increase of Phe over the ripening time were different from what is observed in semi-hard cheese without PAB. The occurrence of cracks was higher in cheeses with more hydrolyzed ?(S1)- and ?-casein, higher content of free amino acids, lower strain at fracture (shorter texture), and a greater number of PAB. PMID:21338776

Rehn, U; Vogensen, F K; Persson, S-E; Hallin Saedén, K; Nilsson, B F; Ardö, Y

2011-03-01

22

Bioavailability of zinc from zinc sulfate and different organic zinc sources and their effects on ruminal volatile fatty acid proportions  

Microsoft Academic Search

Twenty-four Angus steers were used to determine the effects of dietary zinc (Zn) level and source on Zn metabolism and ruminal volatile fatty acid (VFA) patterns. All steers were fed a low Zn diet (18.8 mg Zn per kg) for 42 days prior to assignment to dietary treatments. Treatments consisted of: (1) control (low Zn diet), (2) Zn sulfate (ZnSO4),

J. W. Spears; P. Schlegel; M. C. Seal; K. E. Lloyd

2004-01-01

23

Regeneration of carboxylic acid-laden basic sorbents by leaching with a volatile base in an organic solvent  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with an organic solution of alkylamine thus forming an alkylamine/carboxylic acid complex which is decomposed with improved efficiency to the desired carboxylic acid and the alkylamine. Carbon dioxide addition can be used to improve the adsorption or the carboxylic acids by the solid phase sorbent.

King, C. Judson (Kensington, CA); Husson, Scott M. (Berkeley, CA)

1999-01-01

24

Volatile organic compound sensor system  

DOEpatents

Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Waxahachie, TX); Sorini-Wong, Susan S. (Laramie, WY); Wong, Gregory K. (Laramie, WY)

2011-03-01

25

Volatile organic compound sensor system  

DOEpatents

Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

Schabron, John F. (Laramie, WY) [Laramie, WY; Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Laramie, WY) [Laramie, WY; Sorini-Wong, Susan S. (Laramie, WY) [Laramie, WY

2009-02-10

26

THEORETICAL EVALUATION OF STABILITY OF VOLATILE ORGANIC CHEMICALS AND POLAR VOLATILE ORGANIC CHEMICALS IN CANISTERS  

EPA Science Inventory

A mathematical model was developed for describing loss by physical adsorption of volatile organic chemicals (VOCs) and polar volatile organic chemicals (PVOCs) in stainless steel canisters. he model incorporates compound specific properties such as polarizability, vapor concentra...

27

Volatile organic compound sensing devices  

DOEpatents

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

Lancaster, Gregory D. (Idaho Falls, ID); Moore, Glenn A. (Idaho Falls, ID); Stone, Mark L. (Idaho Falls, ID); Reagen, William K. (Stillwater, MN)

1995-01-01

28

Volatile organic compound sensing devices  

DOEpatents

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

1995-08-29

29

Regeneration of lactic and succinic acid-laden basic Sorbents byLeaching with a Volatile Base in an Organic Solvent  

SciTech Connect

Leaching with an organic solution of a volatile base wasexplored as a method of regenerating tertiary amine and pyridyl sorbents.Experimental data are presented that show that regeneration efficiencycorrelates with the nonaqueous basicity of the regenerant as measured bythe Gutmann donicity scale. Essentially complete regeneration of lacticacid-laden Dowex MWA-1 was achieved when 8-10 mol of trimethylamine werepresent for every mole of adsorbed acid; adequate (>70 percentregeneration was obtained at a 2:1 molar ratio. The; resultingtrimethylamine-lactic acid complex can be thermally decomposed fully whentrimethylamine is employed in an organic solvent instead of in water. Alikely cause of the incomplete thermal decomposition of trimethylammoniumlactate in previous, water-based systems is the aqueous environment inwhich the decomposition was performed.

Husson, Scott M.; King, C. Judson

1997-09-01

30

Vapor Adsorption of Volatile Organic Compounds Using Organically Modified Clay  

Microsoft Academic Search

Organically modified clay was used to adsorb volatile organic compounds from a gaseous phase. The organoclay was prepared by adsorbing hexadecyltrimethylammonium (HDTMA) on the surface of montmorillonite particles. Two volatile organic compounds (VOCs), chlorobenzene and trichloroethylene, were adsorbed to the organoclay using a fixed adsorption bed. The adsorption was carried out at various inlet concentrations of gaseous VOCs in a

2008-01-01

31

VOLATILE ORGANIC ANALYSIS BY DIRECT AQUEOUS INJECTION  

EPA Science Inventory

Gas chromatographic environmental analysis by direct aqueous injection (DAI) was studied for 24 volatile organic analytes (VOAs). Internal standardization was used to determine the precision of analyzing these compounds by DAI. Aequous samples were directly introduced to a gas ch...

32

Volatile Organic Carbon Emissions. Phase 2.  

National Technical Information Service (NTIS)

Engineering studies evaluated bisulfite (HS03) absorbent solutions in a bench-scale absorption unit for the control of volatile organic compounds (VOCs) emitted from the manufacture of multi-base propellent at Radford Army Ammunition Plant. An optimizatio...

C. A. Jake

1987-01-01

33

Microwave spectra of some volatile organic compounds  

NASA Technical Reports Server (NTRS)

A computer-controlled microwave (MRR) spectrometer was used to catalog reference spectra for chemical analysis. Tables of absorption frequency, peak absorption intensity, and integrated intensity are included for 26 volatile organic compounds, all but one of which contain oxygen.

White, W. F.

1975-01-01

34

Biodiversity of volatile organic compounds from five French ferns.  

PubMed

Five French ferns belonging to different families were investigated for volatile organic compounds (VOC) by GC-MS using organic solvent extraction. Fifty-five VOC biosynthesized from the shikimic, lipidic and terpenic pathways including monoterpenes, sesquiterpenes and carotenoid-type compounds were identified. The main volatile compound of Adiantum capillus-veneris L. (Pteridaceae) was (E)-2-decenal with a plastic or "stink bug" odor. The volatile profiles of Athyrium filix-femina (L.) Roth (Woodsiaceae) and Blechnum spicant (L.) Roth (Blechnaceae) showed similarities, with small amounts of isoprenoids and the same main volatile compounds, i.e., 2-phenylethanal (odor of lilac and hyacinth) and 1-octen-3-ol (mushroom-like odor). The main volatile compound of Dryopteris filix-mas (L.) Schott (Dryopteridaceae) was (E)-nerolidol with a woody or fresh bark note. Polyketides, as acylfilicinic acids, were mainly identified in this fern. Oreopteris limbosperma (Bellardi ex. All.) J. Holub (Thelypteridaceae), well-known for its lemon smell, contained the highest biodiversity of VOC. Eighty percent of the volatiles was issued from the terpenic pathway. The main volatiles were (E)-nerolidol, alpha-terpineol, beta-caryophyllene and other minor monoterpenes (for example, linalool, pinenes, limonene, and gamma-terpinen-7-al). It was also the fern with the highest number of carotenoid-type derivatives, which were identified in large amounts. Our results were of great interest underlying new industrial valorisation for ferns based on their broad spectrum of volatiles. PMID:21121267

Fons, Françoise; Froissard, Didier; Bessière, Jean-Marie; Buatois, Bruno; Rapior, Sylvie

2010-10-01

35

Analyzing method on biogenic volatile organic compounds  

NASA Astrophysics Data System (ADS)

In order to analyze biogenic volatile organic compounds in the atmosphere, an automated gas chromatography is developed and employed at the laboratory of National Center for Atmospheric Research (NCAR) during January to July, 2000. A small refrigerator was used so as to remove water in the air sample from gas line, and get accurate concentrations of volatile organic compounds. At 5degreesC, good water removing efficiency can be obtained at controlled flow rate. Air samples were collected around the building of Mesa Lab. of NCAR and analyzed by this gas chromatography system. This paper reports this gas chromatography system and results of air samples. The experimental results show that this gas chromatography system has a good reproducibility and stability, and main interesting volatile organic compounds such as isoprene, monoterpenes have an evident diurnal variation.

Bai, J. H.; Wang, M. X.; Hu, F.; Greenberg, J. P.; Guenther, A. B.

2002-02-01

36

Catalyst for Oxidation of Volatile Organic Compounds  

NASA Technical Reports Server (NTRS)

Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

2000-01-01

37

Analysis of volatile organic compounds. [trace amounts of organic volatiles in gas samples  

NASA Technical Reports Server (NTRS)

An apparatus and method are described for reproducibly analyzing trace amounts of a large number of organic volatiles existing in a gas sample. Direct injection of the trapped volatiles into a cryogenic percolum provides a sharply defined plug. Applications of the method include: (1) analyzing the headspace gas of body fluids and comparing a profile of the organic volatiles with standard profiles for the detection and monitoring of disease; (2) analyzing the headspace gas of foods and beverages and comparing the profile with standard profiles to monitor and control flavor and aroma; and (3) analyses for determining the organic pollutants in air or water samples.

Zlatkis, A. (inventor)

1977-01-01

38

COMPLETE CATALYTIC OXIDATION OF VOLATILE ORGANICS  

EPA Science Inventory

The paper reviews heterogeneous catalytic oxidation, focusing on its application to the control of volatile organic compounds (VOCs) at operating conditions typical of field applications. The parameters for this review are: low to moderate temperatures (25-400 C), atmospheric pre...

39

Volatile organic compounds of Schenella pityophilus.  

PubMed

Volatile organic compounds of Schenella pityophilus have been identified via solid-phase microextraction-gas chromatography-mass spectrometry analysis. Ten compounds have been identified, in which 3-methylthio-1-propene was the most significant component. Some other components were previously identified in Tuber aestivum and Tuber melanosporum. PMID:22236093

D'Auria, Maurizio; Racioppi, Rocco; Rana, Gian Luigi

2013-01-01

40

Production of poly(hydroxybutyrate-hydroxyvalerate) from waste organics by the two-stage process: Focus on the intermediate volatile fatty acids.  

PubMed

The two-stage process, coupling volatile fatty acids (VFAs) fermentation and poly(hydroxybutyrate-hydroxyvalerate) (P(HB/HV)) biosynthesis, was investigated for five waste organic materials. The overall conversion efficiencies were glycerol>starch>molasses>waste sludge>protein, meanwhile the maximum P(HB/HV) (1.674g/L) was obtained from waste starch. Altering the waste type brought more effects on VFAs composition other than the yield in the first stage, which in turn greatly changed the yield in the second stage. Further study showed that even-number carbon VFAs (or odd-number ones) had a good positive linear relationship with P(HB/HV) content of HB (or HV). Additionally, VFA producing microbiota was analyzed by pyrosequencing methods for five wastes, which indicated that specific species (e.g., Lactobacillus for protein; Ethanoligenens for starch; Ruminococcus and Limnobacter for glycerol) were dominant in the community for VFAs production. Potential competition among acidogenic bacteria specially involved to produce some VFA was proposed as well. PMID:24907579

Shen, Liang; Hu, Hongyou; Ji, Hongfang; Cai, Jiyuan; He, Ning; Li, Qingbiao; Wang, Yuanpeng

2014-08-01

41

Carbon nanotube volatile organic liquid sensor  

NASA Astrophysics Data System (ADS)

Volatile organic liquid sensors with two distinct configurations are developed for a future biosensor using laterally grown carbon nanotubes (CNTs) from two isolated metal electrodes. In the first configuration, the CNTs grown from each electrode weakly contact each other, and the charge transport between them is based on tunneling. In the second configuration, the CNTs in the array are covered with a silicone composite paste and strongly contact each other; Ohmic transport behavior is observed. The signal modulation amplitude with exposure to the volatile organic liquid is higher than two orders in magnitude. The sensing mechanism is based on the capillary force between CNTs and the swelling property of the silicone paste induced by the organic liquids.

Song, Youngsik; Choi, Jaewu

2009-09-01

42

Chemicapacitive microsensors for volatile organic compound detection  

Microsoft Academic Search

A low-cost, low-power volatile organic compound (VOC) sensor has been constructed from an array of micromachined parallel-plate capacitors. The sensor has demonstrated detection of many VOCs well below the lower explosive limits and could be used in industrial leak monitoring applications or for homeland defense. In place of a standard dielectric, the individual capacitors were filled with selectively absorbing polymers.

S. V. Patel; T. E. Mlsna; B. Fruhberger; E. Klaassen; S. Cemalovic; D. R. Baselt

2003-01-01

43

TMVOC, simulator for multiple volatile organic chemicals  

SciTech Connect

TMVOC is a numerical simulator for three-phase non-isothermal flow of water, soil gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. It is an extension of the TOUGH2 general-purpose simulation program developed at the Lawrence Berkeley National Laboratory. TMVOC is designed for applications to contamination problems that involve hydrocarbon fuel or organic solvent spills in saturated and unsaturated zones. It can model contaminant behavior under ''natural'' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. TMVOC is upwards compatible with T2VOC (Falta et al., 1995) and can be initialized from T2VOC-style initial conditions. The main enhancements in TMVOC relative to T2VOC are as follows: a multicomponent mixture of volatile organic chemicals can be modeled; any and all combinations of the three phases water-oil-gas are treated; several non-condensible gases may be present; diffusion is treated in all phases in a manner that is fully coupled with phase partitioning. This paper gives a brief summary of the methodology used in TMVOC as well as highlighting some implementation issues. Simulation of a NAPL spill and subsequent remediation is discussed for a 2-D vertical section of a saturated-unsaturated flow problem.

Pruess, Karsten; Battistelli, Alfredo

2003-03-25

44

Characteristics of the volatile organic compounds -- Arid Integrated Demonstration Site  

SciTech Connect

The Volatile Organic Compounds -- Arid Integrated Demonstration Program (VOC-Arid ID) is targeted at demonstration and testing of technologies for the evaluation and cleanup of volatile organic compounds and associated contaminants at arid DOE sites. The initial demonstration site is an area of carbon tetrachloride (CCl{sub 4}) contamination located near the center of the Hanford Site. The movement of CCl{sub 4} and other volatile organic contaminants in the subsurface is very complex. The problem at the Hanford Site is further complicated by the concurrent discharge of other waste constituents including acids, lard oil, organic phosphates, and transuranic radionuclides. In addition, the subsurface environment is very complex, with large spatial variabilities in hydraulic properties. A thorough understanding of the problem is essential to the selection of appropriate containment, retrieval, and/or in situ remedial technologies. The effectiveness of remedial technologies depends on knowing where the contaminants are, how they are held up in a given physical and chemical subsurface environment; and knowing the physical, chemical, and microbiological changes that are induced by the various remedial technologies.

Last, G.V.; Lenhard, R.J.; Bjornstad, B.N.; Evans, J.C.; Roberson, K.R.; Spane, F.A.; Amonette, J.E.; Rockhold, M.L.

1991-10-01

45

Emissions of volatile fatty acids from feed at dairy facilities  

NASA Astrophysics Data System (ADS)

Recent studies suggest that dairy operations may be a major source of non-methane volatile organic compounds in dairy-intensive regions such as Central California, with short chain carboxylic acids (volatile fatty acids or VFAs) as the major components. Emissions of four VFAs (acetic acid, propanoic acid, butanoic acid and hexanoic acid) were measured from two feed sources (silage and total mixed rations (TMR)) at six Central California Dairies over a fifteen-month period. Measurements were made using a combination of flux chambers, solid phase micro-extraction fibers coupled to gas chromatography mass spectrometry (SPME/GC-MS) and infra-red photoaccoustic detection (IR-PAD for acetic acid only). The relationship between acetic acid emissions, source surface temperature and four sample composition factors (acetic acid content, ammonia-nitrogen content, water content and pH) was also investigated. As observed previously, acetic acid dominates the VFA emissions. Fluxes measured by IR-PAD were systematically lower than SPME/GC-MS measurements by a factor of two. High signals in field blanks prevented emissions from animal waste sources (flush lane, bedding, open lot) from being quantified. Acetic acid emissions from feed sources are positively correlated with surface temperature and acetic acid content. The measurements were used to derive a relationship between surface temperature, acetic acid content and the acetic acid flux. The equation derived from SPME/GC-MS measurements predicts estimated annual average acetic acid emissions of (0.7 + 1/-0.4) g m -2 h -1 from silage and (0.2 + 0.3/-0.1) g m -2 h -1 from TMR using annually averaged acetic acid content and meteorological data. However, during the summer months, fluxes may be several times higher than these values.

Alanis, Phillip; Ashkan, Shawn; Krauter, Charles; Campbell, Sean; Hasson, Alam S.

2010-12-01

46

21 CFR 573.914 - Salts of volatile fatty acids.  

Code of Federal Regulations, 2010 CFR

...salts of mixed 5-carbon acids (as identified in paragraph...Calcium salt of isobutyric acid 26 to 34 percent... 3 percent maximum. Water 14 percent maximum...expressing maximum use levels. For ammonium salts of volatile fatty acids, the...

2009-04-01

47

21 CFR 573.914 - Salts of volatile fatty acids.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

2011-04-01

48

21 CFR 573.914 - Salts of volatile fatty acids.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

2010-04-01

49

21 CFR 573.914 - Salts of volatile fatty acids.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

2012-04-01

50

Alkaline dechlorination of chlorinated volatile organic compounds  

SciTech Connect

The vast majority of contaminated sites in the United States and abroad are contaminated with chlorinated volatile organic compounds (VOCs) such as trichloroethylene (TCE), trichloroethane (TCA), and chloroform. These VOCs are mobile and persistent in the subsurface and present serious health risks at trace concentrations. The goal of this project was to develop a new chemical treatment system that can rapidly and effectively degrade chlorinated VOCs. The system is based on our preliminary findings that strong alkalis such as sodium hydroxide (NaOH) can absorb and degrade TCE. The main objectives of this study were to determine the reaction rates between chlorinated VOCs, particularly TCE, and strong alkalis, to elucidate the reaction mechanisms and by-products, to optimize the chemical reactions under various experimental conditions, and to develop a laboratory bench- scale alkaline destruction column that can be used to destroy vapor- phase TCE.

Gu, B.; Siegrist, R.L.

1996-06-01

51

Formation of volatile chemicals from thermal degradation of less volatile coffee components: quinic acid, caffeic acid, and chlorogenic acid.  

PubMed

The less volatile constituents of coffee beans (quinic acid, caffeic acid, and chlorogenic acid) were roasted under a stream of nitrogen, air, or helium. The volatile degradation compounds formed were analyzed by gas chromatography and gas chromatography-mass spectrometry. Caffeic acid produced the greatest amount of total volatiles. Quinic acid and chlorogenic acid produced a greater number of volatiles under the nitrogen stream than under the air stream. These results suggest that the presence of oxygen does not play an important role in the formation of volatile compounds by the heat degradation of these chemicals. 2,5-Dimethylfuran formed in relatively large amounts (59.8-2231.0 microg/g) in the samples obtained from quinic acid and chlorogenic acid but was not found in the samples from caffeic acid. Furfuryl alcohol was found in the quinic acid (259.9 microg/g) and caffeic acid (174.4 microg/g) samples roasted under a nitrogen stream but not in the chlorogenic sample. The three acids used in the present study do not contain a nitrogen atom, yet nitrogen-containing heterocyclic compounds, pyridine, pyrrole, and pyrazines, were recovered. Phenol and its derivatives were identified in the largest quantities. The amounts of total phenols ranged from 60.6 microg/g (quinic acid under helium) to 89893.7 microg/g (caffeic acid under helium). It was proposed that phenol was formed mainly from quinic acid and that catechols were formed from caffeic acid. Formation of catechol from caffeic acid under anaerobic condition indicates that the reaction participating in catechol formation was not oxidative degradation. PMID:20405916

Moon, Joon-Kwan; Shibamoto, Takayuki

2010-05-12

52

Gas phase measurements of pyruvic acid and its volatile metabolites.  

PubMed

Pyruvic acid, central to leaf carbon metabolism, is a precursor of many volatile organic compounds (VOCs) that impact air quality and climate. Although the pathways involved in the production of isoprenoids are well-known, those of several oxygenated VOCs remain uncertain. We present concentration and flux measurements of pyruvic acid and other VOCs within the tropical rainforest (TRF) biome at Biosphere 2. Pyruvic acid concentrations varied diurnally with midday maxima up to 15 ppbv, perhaps due to enhanced production rates and suppression of mitochondrial respiration in the light. Branch fluxes and ambient concentrations of pyruvic acid correlated with those of acetone, acetaldehyde, ethanol, acetic acid, isoprene, monoterpenes, and sesquiterpenes. While pyruvic acid is a known substrate for isoprenoid synthesis, this correlation suggests that the oxygenated VOCs may also derive from pyruvic acid, an idea supported by leaf feeding experiments with sodium pyruvate which resulted in large enhancements in emissions of both isoprenoids and oxygenated VOCs. While feeding with sodium pyruvate-2-(13)C resulted in large emissions of both (13)C-labeled isoprenoids and oxygenated VOCs, feeding with sodium pyruvate-1-(13)C resulted in only (13)C-labeled isoprenoids. This suggests that acetaldehyde, ethanol, and acetic acid are produced from pyruvic acid via the pyruvate dehydrogenase (PDH) bypass system (in which the 1-C carbon of pyruvic acid is lost as CO(2)) and that acetone is also derived from the decarboxylation of pyruvic acid. PMID:20210357

Jardine, Kolby J; Sommer, Evan D; Saleska, Scott R; Huxman, Travis E; Harley, Peter C; Abrell, Leif

2010-04-01

53

Volatile organic compounds (VOCs) in urban atmosphere of Hong Kong  

Microsoft Academic Search

The assessment of volatile organic compounds (VOCs) has become a major issue of air quality network monitoring in Hong Kong. This study is aimed to identify, quantify and characterize volatile organic compounds (VOCs) in different urban areas in Hong Kong. The spatial distribution, temporal variation as well as correlations of VOCs at five roadside sampling sites were discussed. Twelve VOCs

S. C. Lee; M. Y. Chiu; K. F. Ho; S. C. Zou; Xinming Wang

2002-01-01

54

BIOCONCENTRATION FACTORS FOR VOLATILE ORGANIC COMPOUNDS IN VEGETATION  

EPA Science Inventory

Samples of air and leaves were taken at the University of Nevada-Las Vegas campus and analyzed for volatile organic compounds using vacuum distillation coupled with gas chromatography/mass spectrometry. The data were used to estimate the bioconcentration of volatile organic compo...

55

DYNAMIC ANALYSIS OF SORPTION OF VOLATILE ORGANIC COMPOUNDS IN WATER  

Microsoft Academic Search

Chlorinated and brominated volatile organic compounds are among the groundwater pollutants creating major environmental problems. In this study, dynamic behavior of certain volatile organic compounds in water was investigated by using a novel moment technique. Adsorption equilibrium constant and the penetration length of tracers were evaluated by the first absolute and the second central moment expressions derived for a pulse-response

Nail Yasyerli; Ugur Harbili

2008-01-01

56

PHASE DISTRIBUTIONS OF LOW VOLATILITY ORGANICS IN AMBIENT AIR  

EPA Science Inventory

Current strategies to control photochemical air pollution rely on abating the emission of volatile organic compounds. Primarily, these compounds exist in the vapor phase, and are those with a carbon number of ten or less. Recent attention has been given to low-volatility organic ...

57

Temporal Variability Measurement of Specific Volatile Organic Compounds  

Microsoft Academic Search

Methodology was developed to unambiguously determine trace levels of volatile organic compounds as they vary in concentration over a variety of time scales. This capability is important because volatile organic compounds (VOCs) are usually measured by time-integrative techniques that average out peak exposures to insignificance. The specific method presented here involves a preprogrammed sequential syringe sampler that can fill 150-cm

Joachim D. Pleil; William A. McClenny; Karen D. Oliver

1989-01-01

58

COMPARISON OF AMBIENT AIR SAMPLING TECHNIQUES FOR VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

A series of fourteen experimental sampling runs were carried out at a field site to collect data from several ambient air monitoring methods for volatile organic compounds (VOCs). Ambient air was drawn through a sampling manifold and was continuously spiked with volatile organic ...

59

40 CFR 60.452 - Standard for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Standard for volatile organic compounds. 60.452 Section 60.452 Protection of Environment...Coating: Large Appliances § 60.452 Standard for volatile organic compounds. On or after the date on which the...

2013-07-01

60

40 CFR 60.462 - Standards for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.462 Section 60.462 Protection of Environment...Coil Surface Coating § 60.462 Standards for volatile organic compounds. (a) On and after the date on which §...

2013-07-01

61

Production of volatile organic compounds by mycobacteria.  

PubMed

The need for improved rapid diagnostic tests for tuberculosis disease has prompted interest in the volatile organic compounds (VOCs) emitted by Mycobacterium tuberculosis complex bacteria. We have investigated VOCs emitted by Mycobacterium bovis BCG grown on Lowenstein-Jensen media using selected ion flow tube mass spectrometry and thermal desorption-gas chromatography-mass spectrometry. Compounds observed included dimethyl sulphide, 3-methyl-1-butanol, 2-methyl-1-propanol, butanone, 2-methyl-1-butanol, methyl 2-methylbutanoate, 2-phenylethanol and hydrogen sulphide. Changes in levels of acetaldehyde, methanol and ammonia were also observed. The compounds identified are not unique to M. bovis BCG, and further studies are needed to validate their diagnostic value. Investigations using an ultra-rapid gas chromatograph with a surface acoustic wave sensor (zNose) demonstrated the presence of 2-phenylethanol (PEA) in the headspace of cultures of M. bovis BCG and Mycobacterium smegmatis, when grown on Lowenstein-Jensen supplemented with glycerol. PEA is a reversible inhibitor of DNA synthesis. It is used during selective isolation of gram-positive bacteria and may also be used to inhibit mycobacterial growth. PEA production was observed to be dependent on growth of mycobacteria. Further study is required to elucidate the metabolic pathways involved and assess whether this compound is produced during in vivo growth of mycobacteria. PMID:22224870

McNerney, Ruth; Mallard, Kim; Okolo, Phyllis Ifeoma; Turner, Claire

2012-03-01

62

Formation of organic nanoparticles from volatile microemulsions.  

PubMed

A method for preparation of nanoparticles of poorly water-soluble organic materials is presented. By this method, an oil-in-water microemulsion containing a volatile solvent with dissolved model material, propylparaben, undergoes solvent evaporation and conversion into nanoparticles by spray drying. The resulting powder can be easily dispersed in water to give a clear, stable dispersion of nanoparticles with a high loading of propylparaben. By filtration of this dispersion it was found that more than 95wt.% of the dispersed propylparaben is in particles of less than 450nm. X-ray diffraction revealed that propylparaben is present as nanocrystals of 40-70nm. After dispersion of the powder in water, formation of large crystals rapidly occurs. Addition of polyvinylpyrrolidone (PVP) prevented crystal growth during dispersion of the powder in water. The inhibition of propylparaben crystal growth by PVP was studied by molecular dynamic simulations that addressed the binding of PVP to the propylparaben crystal. A comparison was made between PVP and polyvinylalcohol, which did not display crystal inhibition properties. PMID:19919861

Margulis-Goshen, Katrin; Netivi, Hadas Donio; Major, Dan T; Gradzielski, Michael; Raviv, Uri; Magdassi, Shlomo

2010-02-15

63

77 FR 16940 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Volatile Organic...  

Federal Register 2010, 2011, 2012, 2013

...Implementation Plans; Illinois; Volatile Organic Compound Emission Control Measures for...technology (RACT) for sources of volatile organic compound (VOC) emissions in moderate...to approve into Illinois' SIP volatile organic material (VOM), which is the same...

2012-03-23

64

78 FR 24990 - Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission...  

Federal Register 2010, 2011, 2012, 2013

...Implementation Plans; Ohio; Volatile Organic Compound Emission Control Measures for...Implementation Plan (SIP), several volatile organic compound (VOC) rules that were submitted...stationary sources, storage of volatile organic liquids, industrial cleaning...

2013-04-29

65

Molecular Models of Volatile Organic Compounds  

NSDL National Science Digital Library

This month's Featured Molecules come from the Report from Other Journals column, Nature: Our Atmosphere in the Year of Planet Earth, and the summary found there of the paper by Lelieveld et al. (1, 2) Added to the collection are several volatile organic compounds (VOCs) that are emitted by a variety of plants. The term VOCs is a common one in environmental chemistry, and is interpreted quite broadly, typically referring to any organic molecule with a vapor pressure sufficiently high to allow for part-per-billion levels in the atmosphere. Common VOCs include methane (the most prevalent VOC), benzene and benzene derivatives, chlorinated hydrocarbons, and many others. The source may be natural, as in the case of the plant emissions, or anthropogenic, as in the case of a molecule such as the gasoline additive methyl tert-butyl ether (MTBE).The oxidation of isoprene in the atmosphere has been a source of interest for many years. Several primary oxidation products are included in the molecule collection, although a number of isomeric forms are also possible (3).The area of VOCs provides innumerable topics for students research papers and projects at all levels of the curriculum from high-school chemistry through the undergraduate courses in chemistry and environmental science. Along the way students have the opportunity for exposure to fields such as epidemiology and toxicology, that may be new to them, but are of increasing importance in the environmental sciences. The MTBE story is an interesting one for students to discover, as it once again emphasizes the role that unintended consequences play in life. An exploration of the sources, structures, reactivity, health and environmental effects and ultimate fate of various VOCs reinforces in students minds just how interconnected the chemistry of the environment is, a lesson that bears repeating frequently.

66

Breath measurements as volatile organic compound biomarkers.  

PubMed Central

A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water.

Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

1996-01-01

67

Volatile Organic Compound Analysis in Istanbul  

NASA Astrophysics Data System (ADS)

Volatile Organic Compound Analysis in Istanbul Ö. Çapraz1, A. Deniz1,3, A. Ozturk2, S. Incecik1, H. Toros1 and, M. Coskun1 (1) Istanbul Technical University, Faculty of Aeronautics and Astronautics, Department of Meteorology, 34469, Maslak, Istanbul, Turkey. (2) Istanbul Technical University, Faculty of Chemical and Metallurgical, Chemical Engineering, 34469, Maslak, Istanbul, Turkey. (3) Marmara Clean Air Center, Ministry of Environment and Urbanization, Ni?anta??, 34365, ?stanbul, Turkey. One of the major problems of megacities is air pollution. Therefore, investigations of air quality are increasing and supported by many institutions in recent years. Air pollution in Istanbul contains many components that originate from a wide range of industrial, heating, motor vehicle, and natural emissions sources. VOC, originating mainly from automobile exhaust, secondhand smoke and building materials, are one of these compounds containing some thousands of chemicals. In spite of the risks to human health, relatively little is known about the levels of VOC in Istanbul. In this study, ambient air quality measurements of 32 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in Ka??thane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Ka??thane creek valley is the source part of the Golden Horn and one of the most polluted locations in Istanbul due to its topographical form and pollutant sources in the region. In this valley, horizontal and vertical atmospheric motions are very weak. The target compounds most commonly found were benzene, toluene, xylene and ethyl benzene. Concentrations of total hydrocarbons ranged between 1.0 and 10.0 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations and no single factor seemed to explain trends for this group of compounds. N-octane, 3-methylheptane, n-nonane, 2,3,4-trimethylpentane and n-hexane parameters ranged between 3 ppbv and maximum value of 10 ppbv. The other VOC parameters are measured below 3 ppbv value. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly in?uence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde. Keywords: Air quality, Volatile Organic Compounds (VOC), industry, meteorology, urban, Ka??thane, ?stanbul. Acknowledgment: This work was part of the TUJJB-TUMEHAP-01-10 and Turkish Scientific and Technical Research Council Project No: 109Y132.

?apraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Co?kun, M.

2012-04-01

68

Secondary organic aerosol from biogenic volatile organic compound mixtures  

NASA Astrophysics Data System (ADS)

The secondary organic aerosol (SOA) yields from the ozonolysis of a Siberian fir needle oil (SFNO), a Canadian fir needle oil (CFNO), and several SOA precursor mixtures containing reactive and non-reactive volatile organic compounds (VOCs) were investigated. The use of precursor mixtures more completely describes the atmosphere where many VOCs exist. The addition of non-reactive VOCs such as bornyl acetate, camphene, and borneol had very little to no effect on SOA yields. The oxidation of VOC mixtures with VOC mass percentages similar to the SFNO produced SOA yields that became more similar to the SOA yield from SFNO as the complexity and concentration of VOCs within the mixture became more similar to overall SFNO composition. The SOA yield produced by the oxidation of CFNO was within the error of the SOA yield produced by the oxidation of SFNO at a similar VOC concentration. The SOA yields from SFNO were modeled using the volatility basis set (VBS), which predicts the SOA yields for a given mass concentration of mixtures containing similar VOCs.

Hatfield, Meagan L.; Huff Hartz, Kara E.

2011-04-01

69

Modeling the transport of volatile organics in variably saturated media  

Microsoft Academic Search

The understanding of the processes of dissolution, volatilization, and gas-liquid partitioning in porous media is very limited. The few models which attempt to characterize the transport of volatile organics such as petroleum products and halogenated hydrocarbon solvents in variably saturated media all assume that mass transfer processes are at equilibrium. In addition, gas phase advection is neglected by assuming that

B. E. Sleep; J. F. Sykes

1989-01-01

70

Chronic effect of cadmium in sediments on colonization by benthic marine organisms: An evaluation of the role of interstitial cadmium and acid-volatile sulfide in biological availability  

SciTech Connect

The role of interstitial cadmium and acid-volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked to achieve nominal cadmium/AVS molar ratios of 0.0 (control), 0.1, 0.8, and 3.0 in this 118-d test. Oxidation of AVS in the surficial 2.4 cm within 2 to 4 weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 cadmium/AVS treatment measured simultaneously extracted metal (SEM{sub Cd}) was always less than AVS. Interstitial cadmium concentrations were less than those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 cadmium/AVS treatment, measured SEM{sub Cd} commonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations were of likely toxicological significance to highly sensitive species. Shifts in the presence or absence over all taxa, and fewer macrobenthic polychaetes (Mediomastus ambiseta, Streblospio benedicti, and Podarke obscurea) and unidentified meiofaunal nematodes, were observed. In the nominal 3.0 cadmium/AVS treatment, concentrations of SEM{sub Cd} were always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 {micro}g/L. In addition to the effects above, the sediments were colonized by fewer macrobenthic species, polychaete species, and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs; and exhibited other impacts. Over all treatments, the observed biological responses were consistent with SEM{sub Cd}/AVS ratios in surficial sediments and interstitial water cadmium concentrations.

Hansen, D.J.; Berry, W.J.; Benyi, S.J. [Environmental Protection Agency, Narragansett, RI (United States); Mahony, J.D. [Manhattan Coll., New York, NY (United States). Dept. of Environmental Engineering; Corbin, J.M. [Texas Natural Resource Conservation Commission, Austin, TX (United States). Environmental Assessment Div.; Pratt, S.D. [Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography; Toro, D.M. di [Manhattan Coll., New York, NY (United States). Dept. of Environmental Engineering]|[HydroQual, Inc., Mahwah, NJ (United States); Abel, M.B. [Univ. of Rhode Island, Kingston, RI (United States). Botany Dept.

1996-12-01

71

40 CFR 60.492 - Standards for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Beverage Can Surface Coating Industry § 60.492 Standards for volatile organic compounds. On or after the date on...

2013-07-01

72

40 CFR 60.392 - Standards for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds. On and...

2013-07-01

73

Preparing Soil Samples for Volatile Organic Compound Analysis.  

National Technical Information Service (NTIS)

Three equilibrium headspace and three solvent extraction methods of preparing soil samples for determining volatile organic compounds (VOCs) were compared. Soil samples were spiked with five gasoline range aromatic compounds and four chlorinated compounds...

A. D. Hewitt

1997-01-01

74

GLOBAL INVENTORY OF VOLATILE ORGANIC COMPOUND EMISSIONS FORM ANTHROPOGENIC SOURCES  

EPA Science Inventory

The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

75

IMPROVEMENT IN AIR TOXICS METHODS FOR VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

Innovative and customized monitoring methods for air toxic volatile organic compounds (VOCs) are being developed for applications in exposure and trends monitoring. This task addresses the following applications of specific interest: o Contributions to EPA Regional Monit...

76

DEVELOPMENT OF OZONE REACTIVITY SCALES FOR VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

Methods for developing a numerical scale ranking reactivities of volatile organic compounds (VOCs) towards ozone formation were investigated. ffects of small VOC additions on ozone formation (incremental reactivities) were calculated for 140 types of VOCs in model scenarios repre...

77

Biogenic volatile organic compounds - small is beautiful  

NASA Astrophysics Data System (ADS)

While canopy and regional scale flux measurements of biogenic volatile organic compounds (bVOCs) are essential to obtain an integrated picture of total compound reaching the atmosphere, many fascinating and important emission details are waiting to be discovered at smaller scales, in different ecological and functional compartments. We concentrate on bVOCs below ground to <2m above ground level. Emissions at leaf scale are well documented and widely presented, and are not discussed here. Instead we describe some details of recent research on rhizosphere bVOCs, and bVOCs associated with pollination of flowers. Although bVOC emissions from soil surfaces are small, bVOCs are exuded by roots of some plant species, and can be extracted from decaying litter. Naturally occurring monoterpenes in the rhizosphere provide a specialised carbon source for micro-organisms, helping to define the micro-organism community structure, and impacting on nutrient cycles which are partly controlled by microorganisms. Naturally occurring monoterpenes in the soil system could also affect the aboveground structure of ecosystems because of their role in plant defence strategies and as mediating chemicals in allelopathy. A gradient of monoterpene concentration was found in soil around Pinus sylvestris and Pinus halepensis, decreasing with distance from the tree. Some compounds (?-pinene, sabinene, humulene and caryophyllene) in mineral soil were linearly correlated with the total amount of each compound in the overlying litter, indicating that litter might be the dominant source of these compounds. However, ?-pinene did not fall within the correlation, indicating a source other than litter, probably root exudates. We also show that rhizosphere bVOCs can be a carbon source for soil microbes. In a horizontal gradient from Populus tremula trees, microbes closest to the tree trunk were better enzymatically equipped to metabolise labeled monoterpene substrate. Monoterpenes can also increase the degradation rate in soil of the persistant organic pollutants, likely acting as analogues for the cometabo-lism of polychlorinated biphenyls (PCBs) Flowers of a ginger species (Alpinia kwangsiensis) and a fig species (Ficus hispida) showed different bVOC signals pre- and post pollination. For Ficus hispida, there are three floral stages of a fig-wasp dependency mechanism: receptive, post pollinator and interfloral. Of 28 compounds detected, transcaryophyllene with trans-?-farnesene were the most important at the receptor stage, trans-caryophyllene was the most abundant at the post-pollinator stage, and isoprene was the most abundant in the interfloral stage. Alpinia kwangsiensis presents two morphologies for the reproductive parts of the flower. The "anaflexistyle" morphology has the flower style lowered in the morning and raised in the afternoon. This is reversed for the "cataflexistyle" morphology. The bVOC mixture emitted by each morphology in morning and afternoon was complex. However for compounds showing a difference (cis-ocimene and Z + E epoxy -ocimene), the emissions from the anaflexistyle were greater than from the cataflexistyle, and were greater in the afternoon compared with the morning emissions. Where large flowering plant species are abundant, big changes in monoterpene emissions at < 2m above ground level over relatively small periods of time during pollination are likely to be missed in larger scale integrated flux measurements.

Owen, S. M.; Asensio, D.; Li, Q.; Penuelas, J.

2012-12-01

78

Volatile organic compound sources for Southern Finland  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) have several sources, both biogenic and anthropogenic. Emissions of biogenic VOCs in a global scale are estimated to be an order of magnitude higher than anthropogenic ones. However, in densely populated areas and during winter time the anthropogenic VOC emissions dominate over the biogenic ones. The aim of this study was to clarify potential local sources and source areas of VOCs in different seasons. Diurnal behaviour in winter and spring were also compared at two different sites in Finland: SMEAR II and III (Station for Measuring Ecosystem - Atmosphere Relations). SMEAR II is a rural site located in Hyytiälä in Southern Finland 220 km North-West from Helsinki whereas SMEAR III is background urban site located 5 km from the downtown of Helsinki. The volume mixing ratios of VOCs were measured with a proton-transfer-reaction mass spectrometer (PTR-MS, Ionicon Analytik GmbH, Austria) during years 2006-2011. Other trace gases such as CO, NOXand SO2 were also measured in both sites and used for source analysis. Source areas for long term VOC measurements were investigated with trajectory analysis and sources for local and regional concentrations were determined by Unmix multivariate receptor model. Forest fires affect air quality and the biggest smoke plumes can be seen in satellite images and even hinder visibility in the plume areas. They provide temporally and spatially well-defined sources that can be used to verify source area estimates. During the measurement periods two different forest fire episodes with several hotspots, happened in Russia. Forest fires which showed up in these measurements were in 2006 near the border of Finland in Vyborg area and 2010 in Moscow area. Forest fire episodes were clearly observed in trajectory analysis for benzene, toluene and methanol and also CO and NOX. In addition to event sources continuous source areas were determined. Anthropogenic local sources seemed to be dominant during winter in both sites. However during spring biogenic influence increased. In addition to source analysis this behaviour was visible in enhanced diurnal cycles of VOCs (Patokoski et al., 2014, in press). We will present important sources and source areas for Southern Finland's concentrations. References: Patokoski, J., Ruuskanen, T.M., Hellén, H., Taipale, R., Grönholm, T., Kajos, M.K., Petäjä, T., Hakola, H., Kulmala, M. & Rinne, J., 2014. Winter to spring transition and diurnal variation of VOCs in Finland at an urban background site and a rural site. Boreal Env. Res. 19. In press.

Patokoski, Johanna; Ruuskanen, Taina M.; Kajos, Maija K.; Taipale, Risto; Rantala, Pekka; Aalto, Juho; Ryyppö, Timo; Hakola, Hannele; Rinne, Janne

2014-05-01

79

Control of Volatile Organic Compound Emissions from Volatile Organic Liquid Storage in Floating and Fixed Roof Tanks. Guideline Series.  

National Technical Information Service (NTIS)

Control Techniques Guidelines (CTG) are documents prepared by the EPA that serve as guidance to States in developing reasonably available control technology (RACT). The CTG's contain volatile organic compound (VOC) emissions and control technology informa...

1993-01-01

80

Volatile organic compounds from a Tuber melanosporum fermentation system.  

PubMed

A total of 59 volatile organic compounds (VOCs) were identified from Tuber melanosporum fermentation: 53 from its fermented mycelia and 32 from the fermentation broth. Alcohol-derived compounds were predominant in both the fermentation mycelia and the broth, although long chain fatty acids and isoprenoids were, for the first time, also found in the mycelia. The intense wine bouquet properties of the broth arose from several specific flavor substances, including sulfur compounds, pyrazines, furans and jasmones. Comparing the VOCs identified in this work with those previously reported, our results are more similar to the composition of the Tuber fruiting-body than previous Tuber fermentations. The composition and accumulation of flavor volatiles (e.g., pyrazines, sulfur compounds, and esters) and major constituents (e.g., 3-methyl-1-butanol and 2-phenylethanol) in this fermentation were significantly influenced by the sucrose concentration in the medium. The obtained information could therefore be useful in applications to convert the flavors of truffle mycelia similar to those of the fruiting-body by optimising the fermentation process. PMID:22980851

Li, Yuan-Yuan; Wang, Guan; Li, Hong-Mei; Zhong, Jian-Jiang; Tang, Ya-Jie

2012-12-15

81

Fatty Acid Composition and Volatile Constituents of Protaetia brevitarsis Larvae  

PubMed Central

A total of 48 different volatile oils were identified form P. brevitarsis larvae by gas chromatography/mass spectrometry (GC/MS). Acids (48.67%) were detected as the major group in P. brevitarsis larvae comprising the largest proportion of the volatile compounds, followed by esters (19.84%), hydrocarbons (18.90%), alcohols (8.37%), miscellaneous (1.71%), aldehydes (1.35%) and terpenes (1.16%). The major volatile constituents were 9-hexadecenoic acid (16.75%), 6-octadecenoic acid (14.88%) and n-hexadecanoic acid (11.06%). The composition of fatty acid was also determined by GC analysis and 16 fatty acids were identified. The predominant fatty acids were oleic acid (C18:1, 64.24%) followed by palmitic acid (C16:0, 15.89%), palmitoleic acid (C16:1, 10.43%) and linoleic acid (C18:2, 4.69%) constituting more than 95% of total fatty acids. The distinguished characteristic of the fatty acid profile of P. brevitarsis larvae was the high proportion of unsaturated fatty acid (80.54% of total fatty acids) versus saturated fatty acids (19.46% of total fatty acids). Furthermore, small but significant amounts of linoleic, linolenic and ?-linolenic acids bestow P. brevitarsis larvae with considerable nutritional value. The novel findings of the present study provide a scientific basis for the comprehensive utilization of the insect as a nutritionally promising food source and a possibility for more effective utilization.

Yeo, Hyelim; Youn, Kumju; Kim, Minji; Yun, Eun-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

2013-01-01

82

Fate of Volatile Organic Compounds in Constructed Wastewater Treatment Wetlands  

USGS Publications Warehouse

The fate of volatile organic compounds was evaluated in a wastewater-dependent constructed wetland near Phoenix, AZ, using field measurements and solute transport modeling. Numerically based volatilization rates were determined using inverse modeling techniques and hydraulic parameters established by sodium bromide tracer experiments. Theoretical volatilization rates were calculated from the two-film method incorporating physicochemical properties and environmental conditions. Additional analyses were conducted using graphically determined volatilization rates based on field measurements. Transport (with first-order removal) simulations were performed using a range of volatilization rates and were evaluated with respect to field concentrations. The inverse and two-film reactive transport simulations demonstrated excellent agreement with measured concentrations for 1,4-dichlorobenzene, tetrachloroethene, dichloromethane, and trichloromethane and fair agreement for dibromochloromethane, bromo-dichloromethane, and toluene. Wetland removal efficiencies from inlet to outlet ranged from 63% to 87% for target compounds.

Keefe, S. H.; Barber, L. B.; Runkel, R. L.; Ryan, J. N.

2004-01-01

83

Analysis of volatile organic compounds from illicit cocaine samples  

SciTech Connect

Detection of illicit cocaine hydrochloride shipments can be improved if there is a greater understanding of the identity and quantity of volatile compounds present. This study provides preliminary data concerning the volatile organic compounds detected in a limited Set of cocaine hydrochloride samples. In all cases, cocaine was one of the major volatile compounds detected. Other tropeines were detected in almost all samples. Low concentrations of compounds that may be residues of processing solvents were observed in some samples. The equilibrium emissivity of. cocaine from cocaine hydrochloride was investigated and a value of 83 parts-per-trillion was determined.

Robins, W.H.; Wright, B.W.

1994-07-01

84

Speciation of volatile organic compounds from poultry production  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) emitted from poultry production are leading source of air quality problems. However, little is known about the speciation and levels of VOCs from poultry production. The objective of this study was the speciation of VOCs from a poultry facility using evacuated canisters and sorbent tubes. Samples were taken during active poultry production cycle and between production cycles. Levels of VOCs were highest in areas with birds and the compounds in those areas had a higher percentage of polar compounds (89%) compared to aliphatic hydrocarbons (2.2%). In areas without birds, levels of VOCs were 1/3 those with birds present and compounds had a higher total percentage of aliphatic hydrocarbons (25%). Of the VOCs quantified in this study, no single sampling method was capable of quantifying more than 55% of compounds and in several sections of the building each sampling method quantified less than 50% of the quantifiable VOCs. Key classes of chemicals quantified using evacuated canisters included both alcohols and ketones, while sorbent tube samples included volatile fatty acids and ketones. The top five compounds made up close to 70% of VOCs and included: 1) acetic acid (830.1 ?g m -3); 2) 2,3-butanedione (680.6 ?g m -3); 3) methanol (195.8 ?g m -3); 4) acetone (104.6 ?g m -3); and 5) ethanol (101.9 ?g m -3). Location variations for top five compounds averaged 49.5% in each section of the building and averaged 87% for the entire building.

Trabue, Steven; Scoggin, Kenwood; Li, Hong; Burns, Robert; Xin, Hongwei; Hatfield, Jerry

2010-09-01

85

Volatile Organic Sulfur Compounds of Environmental Interest: Dimethyl Sulfide and Methanethiol  

ERIC Educational Resources Information Center

Volatile organic sulfur compounds (VOSCs) have been assigned environmental roles in global warming, acid precipitation, and cloud formation where two important members dimethyl sulfide (CH3)2 S, DMS, and methanethiol, CH3SH, MT, of VOSC group are involved.

Chasteen, Thomas G.; Bentley, Ronald

2004-01-01

86

FIELD VALIDATION OF THE VOLATILE ORGANIC SAMPLING TRAIN (VOST) PROTOCOL  

EPA Science Inventory

With the development of the Volatile Organic Sampling Train (VOST) Protocol (February 1984) to measure organic emissions from hazardous waste incinerators, a wide variety of compounds have been collected and analyzed. Because its use is currently being recommended by regulatory a...

87

Biological aspects of constructing volatile organic compound emission inventories  

Microsoft Academic Search

The: emission of volatile organic compounds (VOCs) from vegetation is subject to numerous biological controls. Past inventories have relied heavily on empirical models which are limited in their ability to simulate the response of organisms to short- and long-term changes in their growth environment. In this review we consider the principal biochemical, physiological and ecological controls over VOC emission with

Ray Fall; Mt Lerdau; Td Sharkey

1995-01-01

88

Fatty Acid and Volatile Oil Compositions of Allomyrina dichotoma Larvae  

PubMed Central

Thirty-two different volatile oils were identified from Allomyrina dichotoma (A. dichotoma) larvae by gas chromatography/mass spectrometry (GC/MS). The major volatile components were 2,2,4-trimethyl-3-carboxyisopropyl pentanoic acid isobutyl ester (5.83%), phenol,2,6-bis(a,a-dimethyl ethyl)-4-(1-methyl-1-phenylethyl) (5.72%), heptacosane (5.49%) and phenol,2,4-bis(1-methyl-1-phenylethyl) (5.47%). The composition of the fatty acids in A. dichotoma larvae was also determined by gas chromatography (GC) and fourteen constituents were identified. Oleic acid (19.13%) was the most abundant fatty acid followed by palmitic acid (12.52%), palmitoleic acid (3.71%) and linoleic acid (2.08%) in 100 g of A. dichotoma larvae on a dry weight basis. The quantity of unsaturated fatty acids (64.00%) were higher than that of saturated ones (36.00%). The predominant fatty acids in A. dichotoma consist of monounsaturated fatty acid (MUFA, 57.70%) such as oleic acid, myristoleic acid and palmitoleic acid, followed by saturated fatty acids (36.00%) and polyunsaturated fatty acids (PUFA, 6.50%). In particular, the presence of essential fatty acids, such as linoleic (5.30%) and linolenic acid (0.40%) give A. dichotoma larvae considerable nutritional and functional value and it may be a useful source for food and/or industrial utilization.

Youn, Kumju; Kim, Ji-Young; Yeo, Hyelim; Yun, Eun-Young; Hwang, Jae-Sam; Jun, Mira

2012-01-01

89

Fatty Acid and Volatile Oil Compositions of Allomyrina dichotoma Larvae.  

PubMed

Thirty-two different volatile oils were identified from Allomyrina dichotoma (A. dichotoma) larvae by gas chromatography/mass spectrometry (GC/MS). The major volatile components were 2,2,4-trimethyl-3-carboxyisopropyl pentanoic acid isobutyl ester (5.83%), phenol,2,6-bis(a,a-dimethyl ethyl)-4-(1-methyl-1-phenylethyl) (5.72%), heptacosane (5.49%) and phenol,2,4-bis(1-methyl-1-phenylethyl) (5.47%). The composition of the fatty acids in A. dichotoma larvae was also determined by gas chromatography (GC) and fourteen constituents were identified. Oleic acid (19.13%) was the most abundant fatty acid followed by palmitic acid (12.52%), palmitoleic acid (3.71%) and linoleic acid (2.08%) in 100 g of A. dichotoma larvae on a dry weight basis. The quantity of unsaturated fatty acids (64.00%) were higher than that of saturated ones (36.00%). The predominant fatty acids in A. dichotoma consist of monounsaturated fatty acid (MUFA, 57.70%) such as oleic acid, myristoleic acid and palmitoleic acid, followed by saturated fatty acids (36.00%) and polyunsaturated fatty acids (PUFA, 6.50%). In particular, the presence of essential fatty acids, such as linoleic (5.30%) and linolenic acid (0.40%) give A. dichotoma larvae considerable nutritional and functional value and it may be a useful source for food and/or industrial utilization. PMID:24471102

Youn, Kumju; Kim, Ji-Young; Yeo, Hyelim; Yun, Eun-Young; Hwang, Jae-Sam; Jun, Mira

2012-12-01

90

REMOVAL OF VOLATILE ORGANIC CONTAMINANTS FROM GROUND WATER  

EPA Science Inventory

Because ground water is a source of potable water for millions of people, an economical means of removing volatile organic contaminants is essential. Laboratory, pilot-scale and full-scale studies are being carried out in the United States of America to determine the effect of va...

91

40 CFR 60.582 - Standard for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

...Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic...this subpart shall either: (1) Use inks with a weighted average VOC content less than 1.0 kilogram VOC per kilogram ink solids at each affected facility,...

2013-07-01

92

AERATION TO REMOVE VOLATILE ORGANIC COMPOUNDS FROM GROUND WATER  

EPA Science Inventory

The interim report presents general information on the use of aeration to remove volatile organic compounds from drinking water for public health reasons. The report illustrates the types of aerators, shows where they are being used, presents a means of estimating aeration perfor...

93

EFFECTS IN HUMANS OF A VOLATILE ORGANIC COMPOUND MIXTURE: SENSORY  

EPA Science Inventory

Time-course actions for symptoms of the sick building syndrome were derived from 66 healthy males exposed to clean air and a volatile organic (VOC) mixture in separate sessions. he mixture contained 22 VOCs (25 mg/m3 total concentration) commonly found air-borne in new or recentl...

94

PHOTOTHERMAL DESTRUCTION OF THE VAPOR OF VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

The contamination of subsurface soil and groundwater by volatile organic compounds (VOCS) is a pervasive problem in the United States. n-situ soil vapor extraction (SVE) and ex-situ thermal desorption are the most adapted technologies for the remediation of contaminated soil whil...

95

Source apportionment of volatile organic compounds in Hong Kong homes  

Microsoft Academic Search

Indoor volatile organic compound (VOC) data obtained in 100 Hong Kong homes were analyzed to investigate the nature of emission sources and their contributions to indoor concentrations. A principal component analysis (PCA) showed that off-gassing of building materials, household products, painted wood products, room freshener, mothballs and consumer products were the major sources of VOCs in Hong Kong homes. The

H. Guo

2011-01-01

96

VOLATILE ORGANIC COMPOUNDS MEASURED IN DEARS PASSIVE SAMPLERS  

EPA Science Inventory

A suite of 27 volatile organic compounds (VOCs) were monitored in personal exposures, indoors and outdoors of participant's residences, and at a central community site during the DEARS summer 2004 monitoring season. The list of VOCs focused on compounds typically associated with ...

97

Assessment of volatile organic compound emissions from ecosystems of China  

Microsoft Academic Search

Isoprene, monoterpene, and other volatile organic compound (VOC) emissions from grasslands, shrublands, forests, and peatlands in China were characterized to estimate their regional magnitudes and to compare these emissions with those from landscapes of North America, Europe, and Africa. Ecological and VOC emission sampling was conducted at 52 sites centered in and around major research stations located in seven different

L. F. Klinger; Q.-J. Li; A. B. Guenther; J. P. Greenberg; B. Baker; J.-H. Bai

2002-01-01

98

Volatile organic compounds at an urban monitoring station in Korea  

Microsoft Academic Search

Measurements of 56 volatile organic compounds (VOC) were undertaken at a monitoring site in Seoul, Korea in 2004. The VOC pollution at the site was evaluated for both functional groups and individual compounds. The highest concentrations for the functional groups were recorded by aromatic (AR: 430ppbC) followed by paraffin (PR), olefin (OF), and alkyne (AK). The mean concentrations of individual

Hang Thi Nguyen; Ki-Hyun Kim; Min-Young Kim

2009-01-01

99

Global observations of oxygenated Volatile Organic Compounds from space  

Microsoft Academic Search

Formaldehyde (HCHO), the smallest aldehyde of the atmosphere and glyoxal (CHO.CHO), the smallest a- dicarbonyl compound, are key intermediate products of the oxidation of volatile organic compounds (VOCs). Due to their short lifetime they are expected to provide valuable information on the global identification of the photochemical hot spots which are attributed to the various emission sources of anthropogenic, biogenic

M. Vrekoussis; F. Wittrock; A. Richter; J. P. Burrows

2008-01-01

100

Volatile organic compounds in ambient air of Mumbai—India  

Microsoft Academic Search

Volatile organic compounds (VOCs) are a major group of air pollutants which play a critical role in atmospheric chemistry. These contribute to toxic oxidants which are harmful to ecosystem, human health and atmosphere. The variability of pollutants is an important factor in determining human exposure to these chemicals. Data on levels of VOCs in developing countries, including India, are lacking.The

Anjali Srivastava; A. E. Joseph; S. Devotta

2006-01-01

101

Volatile organic compounds in some urban locations in United States  

Microsoft Academic Search

Volatile organic compounds (VOCs) have been determined to be human risk factors in urban environments, as well as primary contributors to the formation of photochemical oxidants. Ambient air quality measurements of 54 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in or near 13 urban locations in the United States during September 1996 to August 1997. Air samples were

Mahmoud F. Mohamed; Daiwen Kang; Viney P. Aneja

2002-01-01

102

VOLATILE ORGANIC COMPOUND MODEL (VERSION 1.8) (FOR MICROCOMPUTERS)  

EPA Science Inventory

Future emissions of volatile organic compounds (VOCs) and costs of their control can be estimated by applying growth factors, emission constraints, control cost functions, and capacity retirement rates to the base line estimates of VOC emissions and industrial VOC source capacity...

103

Catalytic oxidation of volatile organic compounds on supported noble metals  

Microsoft Academic Search

Volatile organic compounds (VOCs) are toxic and mainly contribute to the formation of photochemical smog with a consequent remarkable impact to the air quality. A few techniques are available to reduce VOC emission, among them catalytic oxidation is suitable especially for highly diluted VOCs. The development of noble metals and transition metal oxides as catalysts for VOCs oxidation has been

L. F. Liotta

2010-01-01

104

EXPOSURE OF HUMANS TO VOLATILE ORGANIC MIXTURE. III. INFLAMMATORY RESPONSE  

EPA Science Inventory

A set of symptoms has been described during the past two decades which has been called the "sick building syndrome." hese symptoms include eye, nose, and throat irritation; headache; mental fatigue; and respiratory distress. t is likely that volatile organic compounds (VOC) prese...

105

FIELD-DEPLOYABLE MONITORS FOR VOLATILE ORGANIC COMPOUNDS IN AIR  

EPA Science Inventory

Volatile organic compounds in ambient air are usually estimated by trapping them from air or collecting whole air samples and returning them to a laboratory for analysis by gas chromatography using selective detection. ata do not appear for several days, during which sample integ...

106

A global model of natural volatile organic compound emissions  

Microsoft Academic Search

Numerical assessments of global air quality and potential changes in atmospheric chemical constituents require estimates of the surface fluxes of a variety of trace gas species. We have developed a global model to estimate emissions of volatile organic compounds from natural sources (NVOC). Methane is not considered here and has been reviewed in detail elsewhere. The model has a highly

Alex Guenther; C. Nicholas Hewitt; David Erickson; Ray Fall; Chris Geron; Tom Graedel; Peter Harley; Lee Klinger; Manuel Lerdau; W. A. McKay; Tom Pierce; Bob Scholes; Rainer Steinbrecher; Raja Tallamraju; John Taylor; Pat Zimmerman

1995-01-01

107

Screening of Volatile Organic Compounds in River Sediment  

Microsoft Academic Search

Volatile organic compounds (VOCs), such as trichloroethene, toluene and xylenes have been reported to be detected from river water and sediment, because a part of VOCs charged into river can be distributed to river sediment. Fifty-three common VOCs in water have been simultaneously determined with good accuracy and precision by gas chromatography - mass spectrometry (GC\\/MS) with headspace method as

K. Kawata; A. Tanabe; S. Saito; M. Sakai; A. Yasuhara

1997-01-01

108

LEAVES AS INDICATORS OF EXPOSURE TO AIRBORNE VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

The concentration of volatile organic compounds (VOCs) in leaves is primarily a product of airborne exposures and dependent upon bioconcentration factors and release rates. The bioconcentration factors for VOCs in grass are found to be related to their partitioning between octan...

109

NATIONAL AMBIENT VOLATILE ORGANIC COMPOUNDS (VOCS) DATA BASE UPDATE, DOCUMENTATION  

EPA Science Inventory

Data on the observed concentrations of three hundred twenty (320) volatile organic compounds (VOCs) were compiled, critically evaluated, and assembled into a relational data base. Ambient (i.e., outdoor) measurements, indoor data, and data collected with personal monitors are inc...

110

REMOVAL OF VOLATILE ORGANIC CONTAMINANTS FROM GROUND WATER BY ADSORPTION  

EPA Science Inventory

Laboratory and field studies are underway to determine the effectiveness of activated carbon for removing volatile organic compounds from ground water. For fifteen C1 through C6 compounds being considered for possible regulatory action, the adsorption isotherm capacity ranges fro...

111

Portable acoustic wave sensors for volatile organic compounds  

Microsoft Academic Search

Portable acoustic wave sensor (PAWS) systems are being developed for real-time, on-line monitoring of volatile organic compounds (VOC's). These systems are built around acoustic wave (SAW) devices coated with viscoelastic polymers. Two independent responses of the SAW sensor, wave velocity and wave attenuation, are measured to provide information about the chemical species sorbed by the coating. Rapid, reversible detection of

G. C. Frye; R. W. Cernosek; S. J. Martin

1992-01-01

112

Characterization of total volatile organic compound emissions from paints  

Microsoft Academic Search

Recently, Homeswest in Western Australia and Murdoch University developed a project to construct low allergen houses (LAH) in a newly developed suburb. All potential volatile organic compound (VOC) emission materials used in LAH are required to be measured before the construction of LAH, to ensure they are low VOCs emission materials. To protect people sensitive to exposure to VOCs it

H. Guo; F. Murray

2000-01-01

113

Volatile organic compound (VOC) emissions from soil and litter samples  

Microsoft Academic Search

The production of nonmethane volatile organic compounds (VOCs) by soil microbes is likely to have an important influence on soil ecology and terrestrial biogeochemistry. However, soil VOC production has received relatively little attention, and we do not know how the emissions of microbially-produced VOCs vary across soil and litter types. We collected 40 root-free soil and litter samples from a

Jonathan W. Leff; Noah Fierer

2008-01-01

114

Reduction of volatile acidity of acidic wines by immobilized Saccharomyces cerevisiae cells.  

PubMed

Excessive volatile acidity in wines is a major problem and is still prevalent because available solutions are nevertheless unsatisfactory, namely, blending the filter-sterilized acidic wine with other wines of lower volatile acidity or using reverse osmosis. We have previously explored the use of an empirical biological deacidification procedure to lower the acetic acid content of wines. This winemaker's enological practice, which consists in refermentation associated with acetic acid consumption by yeasts, is performed by mixing the acidic wine with freshly crushed grapes, musts, or marc from a finished wine fermentation. We have shown that the commercial strain Saccharomyces cerevisiae S26 is able to decrease the volatile acidity of acidic wines with a volatile acidity higher than 1.44 g?L(-1) acetic acid, with no detrimental impact on wine aroma. In this study, we aimed to optimize the immobilization of S26 cells in alginate beads for the bioreduction of volatile acidity of acidic wines. We found that S26 cells immobilized in double-layer alginate-chitosan beads could reduce the volatile acidity of an acidic wine (1.1 g?L(-1) acetic acid, 12.5 % (v/v) ethanol, pH 3.12) by 28 and 62 % within 72 and 168 h, respectively, associated with a slight decrease in ethanol concentration (0.7 %). Similar volatile acidity removal efficiencies were obtained in medium with high glucose concentration (20 % w/v), indicating that this process may also be useful in the deacidification of grape musts. We, therefore, show that immobilized S. cerevisiae S26 cells in double-layer beads are an efficient alternative to improve the quality of wines with excessive volatile acidity. PMID:23361840

Vilela, A; Schuller, D; Mendes-Faia, A; Côrte-Real, M

2013-06-01

115

Volatile organic compounds released by the entomopathogenic fungus Beauveria bassiana.  

PubMed

The composition of volatile organic compounds (VOC) released by the entomopathogenic fungus Beauveria bassiana (Hyphomycete: Deuteromycotina) utilizing two different carbon sources was investigated. Analyses were performed by solid-phase microextraction (SPME) coupled to capillary gas chromatography (CGC) and CGC-mass spectrometry (MS). Major components in glucose-grown cultures were diisopropyl naphthalenes, ethanol, and sesquiterpenes. Alkane-grown fungal VOC switched to a fingerprint with prevalence of n-decane. This is the first report on the volatiles released by entomopathogenic fungi. PMID:16733086

Crespo, R; Pedrini, N; Juárez, M P; Dal Bello, G M

2008-01-01

116

Volatile organic compounds from garden waste  

Microsoft Academic Search

About 170 compounds were identified in the headspace or liquid exudate from garden waste. Typical for microbiological growth were branched and straight chain alcohols, carboxylic acids and esters C2–C8. Several of the substances have been identified in early studies of compost For some waste samples the organosulfur compound concentration (C1 and C3 mono-, di- and trisulfides) was ca. 10 mg\\/m3

Ken Wilkins; Kjeld Larsen

1996-01-01

117

Volatile fatty acids in the faeces of patients in `germ-free' isolation  

Microsoft Academic Search

Faecal volatile fatty acids represent the end products of the metabolism of the anaerobic flora of the large bowel. The excretion of these volatile acids has been investigated in five leukaemic patients maintained in plastic `germ-free' isolators. Under `isolator' conditions there is a pronounced fall in volatile fatty acid excretion. The possibility that the measurement of these acids may be

D. Gompertz; A. P. Brooks; H. Gaya; A. S. D. Spiers

1973-01-01

118

Quantitative estimates of the volatility of ambient organic aerosol  

NASA Astrophysics Data System (ADS)

Measurements of the sensitivity of organic aerosol (OA, and its components) mass to changes in temperature were recently reported by Huffman et al.~(2009) using a tandem thermodenuder-aerosol mass spectrometer (TD-AMS) system in Mexico City and the Los Angeles area. Here, we use these measurements to derive quantitative estimates of aerosol volatility within the framework of absorptive partitioning theory using a kinetic model of aerosol evaporation in the TD. OA volatility distributions (or "basis-sets") are determined using several assumptions as to the enthalpy of vaporization (?Hvap). We present two definitions of "non-volatile OA," one being a global and one a local definition. Based on these definitions, our analysis indicates that a substantial fraction of the organic aerosol is comprised of non-volatile components that will not evaporate under any atmospheric conditions; on the order of 50-80% when the most realistic ?Hvap assumptions are considered. The sensitivity of the total OA mass to dilution and ambient changes in temperature has been assessed for the various ?Hvap assumptions. The temperature sensitivity is relatively independent of the particular ?Hvap assumptions whereas dilution sensitivity is found to be greatest for the low (?Hvap = 50 kJ/mol) and lowest for the high (?Hvap = 150 kJ/mol) assumptions. This difference arises from the high ?Hvap assumptions yielding volatility distributions with a greater fraction of non-volatile material than the low ?Hvap assumptions. If the observations are fit using a 1 or 2-component model the sensitivity of the OA to dilution is unrealistically high. An empirical method introduced by Faulhaber et al. (2009) has also been used to independently estimate a volatility distribution for the ambient OA and is found to give results consistent with the high and variable ?Hvap assumptions. Our results also show that the amount of semivolatile gas-phase organics in equilibrium with the OA could range from ~20% to 400% of the OA mass, with smaller values generally corresponding to the higher ?Hvap assumptions. The volatility of various OA components determined from factor analysis of AMS spectra has also been assessed. In general, it is found that the fraction of non-volatile material follows the pattern: biomass burning OA < hydrocarbon-like OA < semivolatile oxygenated OA < low-volatility oxygenated OA. Correspondingly, the sensitivity to dilution and the estimated amount of semivolatile gas-phase material for the OA factors follows the reverse order. Primary OA has a substantial semivolatile fraction, in agreement with previous results, while the non-volatile fraction appears to be dominated by oxygenated OA produced by atmospheric aging. The overall OA volatility is thus controlled by the relative contribution of each aerosol type to the total OA burden. Finally, the model/measurement comparison appears to require OA having an evaporation coefficient (?e) substantially greater than 10-2; at this point it is not possible to place firmer constraints on ?e based on the observations.

Cappa, C. D.; Jimenez, J. L.

2010-06-01

119

Quantitative estimates of the volatility of ambient organic aerosol  

NASA Astrophysics Data System (ADS)

Measurements of the sensitivity of organic aerosol (OA, and its components) mass to changes in temperature were recently reported by Huffman et al. (2009) using a tandem thermodenuder-aerosol mass spectrometer (TD-AMS) system in Mexico City and the Los Angeles area. Here, we use these measurements to derive quantitative estimates of aerosol volatility within the framework of absorptive partitioning theory using a kinetic model of aerosol evaporation in the TD. OA volatility distributions (or "basis-sets") are determined using several assumptions as to the enthalpy of vaporization (?Hvap). We present two definitions of "non-volatile OA," one being a global and one a local definition. Based on these definitions, our analysis indicates that a substantial fraction of the organic aerosol is comprised of non-volatile components that will not evaporate under any atmospheric conditions, on the order of 50-80% when the most realistic ?Hvap assumptions are considered. The sensitivity of the total OA mass to dilution and ambient changes in temperature has been assessed for the various ?Hvap assumptions. The temperature sensitivity is relatively independent of the particular ?Hvap assumptions whereas dilution sensitivity is found to be greatest for the low (?Hvap = 50 kJ/mol) and lowest for the high (?Hvap = 150 kJ/mol) assumptions. This difference arises from the high ?Hvap assumptions yielding volatility distributions with a greater fraction of non-volatile material than the low ?Hvap assumptions. If the observations are fit using a 1 or 2-component model the sensitivity of the OA to dilution is unrealistically high. An empirical method introduced by Faulhaber et al. (2009) has also been used to independently estimate a volatility distribution for the ambient OA and is found to give results consistent with the high and variable ?Hvap assumptions. Our results also show that the amount of semivolatile gas-phase organics in equilibrium with the OA could range from ~20% to 400% of the OA mass, with smaller values generally corresponding to the higher ?Hvap assumptions. The volatility of various OA components determined from factor analysis of AMS spectra has also been assessed. In general, it is found that the fraction of non-volatile material follows the pattern: biomass burning OA < hydrocarbon-like OA < semivolatile oxygenated OA < low-volatility oxygenated OA. Correspondingly, the sensitivity to dilution and the estimated amount of semivolatile gas-phase material for the OA factors follows the reverse order. Primary OA has a substantial semivolatile fraction, in agreement with previous results, while the non-volatile fraction appears to be dominated by oxygenated OA produced by atmospheric aging. The overall OA volatility is thus controlled by the relative contribution of each aerosol type to the total OA burden. Finally, the model/measurement comparison appears to require OA having an evaporation coefficient (?e) substantially greater than 10-2; at this point it is not possible to place firmer constraints on ?e based on the observations.

Cappa, C. D.; Jimenez, J. L.

2010-01-01

120

A large source of low-volatility secondary organic aerosol.  

PubMed

Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene ?-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally. PMID:24572423

Ehn, Mikael; Thornton, Joel A; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B; Jørgensen, Solvejg; Kjaergaard, Henrik G; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R; Wildt, Jürgen; Mentel, Thomas F

2014-02-27

121

Development and Evaluation of a Procedure for Determining Volatile Organics in Water (Journal Version).  

National Technical Information Service (NTIS)

A comprehensive procedure for isolation of volatile organic compounds from various waters was developed through the use of representative volatile organic compounds as part of the EPA Master Analytical Scheme. Preliminary recoveries were determined for a ...

L. C. Michael E. D. Pellizzari R. W. Wiseman

1988-01-01

122

Alternative Control Techniques Document: Volatile Organic Liquid Storage in Floating and Fixed Roof Tanks.  

National Technical Information Service (NTIS)

The purpose of the document is to provide information on alternative control techniques (ACT) for volatile organic compound (VOC) emissions from the storage of volatile organic liquids. The control techniques described in the document are applicable to st...

1994-01-01

123

75 FR 2090 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...  

Federal Register 2010, 2011, 2012, 2013

...Indiana; Volatile Organic Compound Automobile Refinishing Rules for Indiana AGENCY...submitted amendments to Indiana's automobile refinishing rule for approval into its...approved volatile organic compound (VOC) automobile refinishing rules to all persons...

2010-01-14

124

75 FR 24404 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...  

Federal Register 2010, 2011, 2012, 2013

...Indiana; Volatile Organic Compound Automobile Refinishing Rules for Indiana AGENCY...Plan (SIP) amendments to Indiana's automobile refinishing rule. These rule revisions...approved volatile organic compound (VOC) automobile refinishing rules to all persons...

2010-05-05

125

Volatile Fatty Acid Requirement of a Strain of Listeria monocytogenes  

PubMed Central

Larson, A. D. (Louisiana State University, Baton Rouge), L. V. Hattier, and C. S. McCleskey. Volatile fatty acid requirement of a strain of Listeria monocytogenes. J. Bacteriol. 89:819–824. 1965.—Listeria monocytogenes strain 2 requires either isobutyric or 2-methylbutyric acid for growth. Elucidation of this requirement began with characterization of the growth-enhancing substance in culture filtrates of Aerobacter aerogenes. A. aerogenes required tryptose, glucose, and aerobic conditions for excretion of active fatty acids into the medium. Commercial preparations of isobutyric, 2-methylbutyric, isovaleric, 3-methylvaleric, and n-valeric acid supported the growth of strain 2. Purification of these fatty acids by gas chromatography demonstrated that strain 2 responded significantly only to isobutyric and 2-methylbutyric acid. Amines, alcohols, and hydroxy fatty acids, which were structurally related to the active acids, did not satisfy the fatty acid requirement of L. monocytogenes strain 2. Only one isolate (strain 2) of 128 cultures of L. monocytogenes required volatile fatty acid for growth. Images

Larson, A. D.; Hattier, L. V.; McCleskey, C. S.

1965-01-01

126

40 CFR Table 1 to Subpart B of... - Volatile Organic Compound (VOC) Content Limits for Automobile Refinish Coatings  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Volatile Organic Compound (VOC) Content Limits for Automobile...PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for...

2013-07-01

127

Role of volatile acids in development of the cecal microflora in broilers chickens during growth  

Microsoft Academic Search

It is known that volatile fatty acids can inhibit growth of species of the family Enterobacteriaceae in vitro. However, whether these volatile fatty acids affect bacterial populations in the ceca of chickens is unknown. Therefore, a study was conducted to investigate if changes in volatile fatty acids in ceca of broiler chickens during growth affect bacterial populations. Results showed that

Wielen van der P. W. J. J; STEEF BIESTERVELD; S. Notermans; H. Hofstra; B. A. P. Urlings; F. van Knapen

2000-01-01

128

Measurement of non-enteric emission fluxes of volatile fatty acids from a California dairy by solid phase micro-extraction with gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Dairies are a major source of volatile organic compounds (VOCs) in California's San Joaquin Valley; a region that experiences high ozone levels during summer. Short-chain carboxylic acids, or volatile fatty acids (VFAs), are believed to make up a large fraction of VOC emissions from these facilities, although there are few studies to substantiate this. In this work, a method using

Phillip Alanis; Mark Sorenson; Matt Beene; Charles Krauter; Brian Shamp; Alam S. Hasson

2008-01-01

129

Soil sampling and analysis for volatile organic compounds  

Microsoft Academic Search

Concerns over data quality have raised many questions related to sampling soils for volatile organic compounds (VOCs). This paper was prepared in response to some of these questions and concerns expressed by Remedial Project Managers (RPMs) and On-Scene Coordinators (OSCs). The following questions are frequently asked:1.Is there a specific device suggested for sampling soils for VOCs?2.Are there significant losses of

T. E. Lewis; A. B. Crockett; R. L. Siegrist

1994-01-01

130

Trees and VOCs: Measuring volatile organic compounds from urban forests  

NSDL National Science Digital Library

This web site describes a research project to measure volatile organic compounds emitted from species of trees and shrubs found in urban areas. Topics include a description of the project and a section on trees and air quality. A page updated each month or so reports field and lab work on the project. There is also a glossary, profiles of community partners, and profiles of the scientists and students involved in the project.

Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado-Boulder; Research, The N.

131

Distribution of volatile organic chemicals in outdoor and indoor air  

NASA Technical Reports Server (NTRS)

The EPA volatile organic chemistry (VOC) national ambient data base (Shah, 1988) is discussed. The 320 chemicals included in the VOC data base are listed. The methods used to obtain the data are reviewed and the availability, accessibility, and operation of the data base are examined. Tables of the daily outdoor concentrations for 66 chemicals and the daily indoor concentrations for 35 chemicals are presented.

Shah, Jitendra J.; Singh, Hanwant B.

1988-01-01

132

Artificial Neural Network Electronic Nose for Volatile Organic Compounds  

Microsoft Academic Search

Advanced microsystems that include, sensors, interface-circuits, and pattern-recognition integrated monolithically or in a hybrid module are needed for civilian, military, and space applications. These include: automotive, medical applications, environmental engineering, and manufacturing automation. ASICs with Artificial Neural Networks (ANN) are considered in this paper, with the objective of recognizing air-borne volatile organic compounds, especially alcohols, ethers, esters, halocarbons, NH3, NO2,

Hoda S. Abdel-aty-zohdy

1998-01-01

133

Source characteristics of oxygenated volatile organic compounds and hydrogen cyanide  

Microsoft Academic Search

Airborne trace gas measurements from Transport and Chemical Evolution over the Pacific (TRACE-P), Pacific Exploratory Mission (PEM)-Tropics B, and Intercontinental Chemical Transport Experiment-North America (INTEX-NA) experiments are analyzed to examine the major source factors contributing to the observed variabilities of oxygenated volatile organic compounds and cyanides. The positive matrix factorization method is applied to coincident measurements of 11 chemicals including

Changsub Shim; Yuhang Wang; Hanwant B. Singh; Donald R. Blake; Alex B. Guenther

2007-01-01

134

Corrosion of electrodeposited copper by exposure to volatile organic compounds  

Microsoft Academic Search

In this paper we investigate the corrosive behaviour of various volatile organic compounds (VOCs) on electroplated copper.\\u000a The VOCs we considered were of the following types: (i) aromatic and substituted-aromatic compounds (benzene, toluene and\\u000a ethyl benzene); (ii) a chlorine-substituted hydrocarbon (dichloromethane) and (iii) an aliphatic alcohol (isopropyl alcohol).\\u000a Contamination by VOCs is typical of ULSI (Ultra Large Scale Integration) manufacturing

Lucia D’Urzo; Benedetto Bozzini

2009-01-01

135

Portable acoustic wave sensors for volatile organic compounds  

Microsoft Academic Search

Portable acoustic wave sensor (PAWS) systems are being developed for real-time, on-line monitoring of volatile organic compounds (VOC`s). These systems are built around acoustic wave (SAW) devices coated with viscoelastic polymers. Two independent responses of the SAW sensor, wave velocity and wave attenuation, are measured to provide information about the chemical species sorbed by the coating. Rapid, reversible detection of

G. C. Frye; R. W. Cernosek; S. J. Martin

1992-01-01

136

Characterization of total volatile organic compound emissions from paints  

Microsoft Academic Search

Recently, Homeswest in Western Australia and Murdoch University developed a project to construct low allergen houses (LAH)\\u000a in a newly developed suburb. All potential volatile organic compound (VOC) emission materials used in LAH are required to\\u000a be measured before the construction of LAH, to ensure they are low VOCs emission materials. To protect people sensitive to\\u000a exposure to VOCs it

H. Guo; F. Murray

2000-01-01

137

Degradation of volatile organic compounds with thermally activated persulfate oxidation  

Microsoft Academic Search

This study investigated the extent and treatability of the degradation of 59 volatile organic compounds (VOCs) listed in the EPA SW-846 Method 8260B with thermally activated persulfate oxidation. Data on the degradation of the 59 VOCs (in mixture) reacted with sodium persulfate in concentrations of 1gl?1 and 5gl?1 and at temperatures of 20°C, 30°C, and 40°C were obtained. The results

Kun-Chang Huang; Zhiqiang Zhao; George E. Hoag; Amine Dahmani; Philip A. Block

2005-01-01

138

Analyses of volatile organic compounds from human skin  

PubMed Central

Summary Background Human skin emits a variety of volatile metabolites, many of them odorous. Much previous work has focused upon chemical structure and biogenesis of metabolites produced in the axillae (underarms), which are a primary source of human body odour. Nonaxillary skin also harbours volatile metabolites, possibly with different biological origins than axillary odorants. Objectives To take inventory of the volatile organic compounds (VOCs) from the upper back and forearm skin, and assess their relative quantitative variation across 25 healthy subjects. Methods Two complementary sampling techniques were used to obtain comprehensive VOC profiles, viz., solid-phase micro extraction and solvent extraction. Analyses were performed using both gas chromatography/mass spectrometry and gas chromatography with flame photometric detection. Results Nearly 100 compounds were identified, some of which varied with age. The VOC profiles of the upper back and forearm within a subject were, for the most part, similar, although there were notable differences. Conclusions The natural variation in nonaxillary skin odorants described in this study provides a baseline of compounds we have identified from both endogenous and exogenous sources. Although complex, the profiles of volatile constituents suggest that the two body locations share a considerable number of compounds, but both quantitative and qualitative differences are present. In addition, quantitative changes due to ageing are also present. These data may provide future investigators of skin VOCs with a baseline against which any abnormalities can be viewed in searching for biomarkers of skin diseases.

Gallagher, M.; Wysocki, C.J.; Leyden, J.J.; Spielman, A.I.; Sun, X.; Preti, G.

2008-01-01

139

Microbial cycling of volatile organic sulfur compounds in anoxic environments.  

PubMed

Microbial cycling of volatile organic sulfur compounds (VOSC) is investigated due to the impact these compounds are thought to have on environmental processes like global temperature control, acid precipitation and the global sulfur cycle. Moreover, in several kinds of industries like composting plants and the paper industry VOSC are released causing odor problems. Waste streams containing these compounds must be treated in order to avoid the release of these compounds to the atmosphere. This paper describes the general mechanisms for the production and degradation of methanethiol (MT) and dimethyl sulfide (DMS), two ubiquitous VOSC in anaerobic environments. Slurry incubations indicated that methylation of sulfide and MT resulting in MT and DMS, respectively, is one of the major mechanisms for VOSC in sulfide-rich anaerobic environments. An anaerobic bacterium that is responsible for the formation of MT and DMS through the anaerobic methylation of H2S and MT was isolated from a freshwater pond after enrichment with syringate as a methyl group donating compound and sole carbon source. In spite of the continuous formation of MT and DMS, steady state concentrations are generally very low. This is due to the microbial degradation of these compounds. Experiments with sulfate-rich and sulfate-amended sediment slurries demonstrated that besides methanogens, sulfate-reducing bacteria can also degrade MT and DMS, provided that sulfate is available. A methanogen was isolated that is able to grow on DMS as the sole carbon source. A large survey of sediments slurries of various origin demonstrated that both isolates are commonly occurring inhabitants of anaerobic environments. PMID:12188577

Lomans, B P; Pol, A; Op den Camp, H J M

2002-01-01

140

On the flux of oxygenated volatile organic compounds from organic aerosol oxidation  

Microsoft Academic Search

Previous laboratory and field studies suggest that oxidation of organic aerosols can be a source of oxygenated volatile organic compounds (OVOC). Using measurements of atmospheric oxidants and aerosol size distributions performed on the NASA DC-8 during the INTEX-NA campaign, we estimate the potential magnitude of the continental summertime OVOC flux from organic aerosol oxidation by OH to be as large

Alan J. Kwan; John D. Crounse; Antony D. Clarke; Yohei Shinozuka; Bruce E. Anderson; James H. Crawford; Melody A. Avery; Cameron S. McNaughton; William H. Brune; Hanwant B. Singh; Paul O. Wennberg

2006-01-01

141

Measurement of volatile fatty acids in pore water from marine sediments by HPLC  

NASA Astrophysics Data System (ADS)

Lower molecular weight volatile fatty acids are important intermediates in the anaerobic degradation of organic matter in marine sediments. The analysis of these compounds at the low in situ concentrations, however, still presents difficulties. A new derivatization procedure for the analysis of these compounds, coupled with high-performance liquid chromatography, has been modified for the analysis of volatile fatty acids in marine pore water to cover a linear calibration range from 0·5 ? M to 10 m M. The modifications resulted in the detection of concentrations 40 times lower than in the original method and in good recoveries of fatty acid standards added to pore water (mean 101%). This modified procedure was then used to analyse fatty acids in pore water from sediments along a gradient of organic enrichment. The relative ratios of the individual acids were 1:0·1:0·02:0·01:0·02:0·01 for acetate, propionate, n-butyrate 2-methylbutyrate, iso-valerate and n-valerate. There was a tendency for the concentration of the more reduced acids to increase (propionate and n-butyrate) as organic enrichment increased. Several fatty acids were found that have not commonly been reported in marine pore water. These include 2-methylbutyrate, which is a specific anaerobic degradation product of iso-leucine, which, to the authors' knowledge, has not been previously found in marine pore water.

Mueller-Harvey, Irene; John Parkes, R.

1987-11-01

142

Transport, behavior, and fate of volatile organic compounds in streams  

USGS Publications Warehouse

Volatile organic compounds (VOCs) are compounds with chemical and physical properties that allow the compounds to move freely between the water and air phases of the environment. VOCs are widespread in the environment because of this mobility. Many VOCs have properties making them suspected or known hazards to the health of humans and aquatic organisms. Consequently, understanding the processes affecting the concentration and distribution VOCs in the environment is necessary. The U.S. Geological Survey selected 55 VOCs for study. This report reviews the characteristics of the various process that could affect the transport, behavior, and fate of these VOCs in streams.

Rathbun, R. E.

1998-01-01

143

Secondary organic aerosols formed from oxidation of biogenic volatile organic compounds in the Sierra Nevada Mountains of California  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compound (BVOC) emissions, such as isoprene and terpenes, can be oxidized to form less volatile carbonyls, acids, and multifunctional oxygenated products that may condense to form secondary organic aerosols (SOA). This research was designed to assess the contribution of oxidized BVOC emissions to SOA in coniferous forests by collecting high-volume particulate samples for 6 days and 5 nights in the summer of 2003. The samples were analyzed for acids, carbonyls, polyols and alkanes to quantify oxidized BVOCs. Terpene and isoprene oxidation products were among the most abundant chemical species detected with the exception of hexadecanoic acid, octadecanoic acid and two butyl esters of unknown origin. The terpene oxidation products of pinonic acid, pinic acid, nopinone and pinonaldehyde showed clear diurnal cycles with concentrations two- to eight-fold higher at night. These cycles resulted from the diurnal cycles in gaseous terpene concentrations and lower temperatures that enhanced condensation of semivolatile chemicals onto aerosols. The terpene-derived compounds averaged 157 ± 118 ng/m3 of particulate organic matter while the isoprene oxidation compounds, namely the 2-methyltetrols and 2-methylglyceric acid, accounted for 53 ± 19 ng/m3. Together, the terpene and isoprene oxidation products represented 36.9% of the identified organic mass of 490 ± 95 ng/m3. PM10 organic matter loadings in the region were approximately 2.1 ± 1.2 ?g/m3, so about 23% of the organic matter was identified and at least 8.6% was oxidized BVOCs. The BVOC oxidation products we measured were significant, but not dominant, contributors to the regional SOA only 75 km downwind of the Sacramento urban area.

Cahill, Thomas M.; Seaman, Vincent Y.; Charles, M. Judith; Holzinger, Rupert; Goldstein, Allen H.

2006-08-01

144

In situ volatile fatty acids influence biogas generation from kitchen wastes by anaerobic digestion.  

PubMed

Anaerobic digestion is considered to be an efficient way of disposing kitchen wastes, which can not only reduce waste amounts, but also produce biogas. However, the excessive accumulation of volatile fatty acids (VFA) caused by high organic loads will inhibit anaerobic digestion intensively. Effects of the VFA composition on biogas generation and microbial community are still required for the investigation under various organic loads of kitchen wastes. Our results showed that the maximum specific methane production was 328.3mlgTS(-1), and acetic acid was the main inhibitor in methanogenesis. With the increase of organic load, aceticlastic methanogenesis was more sensitive to acetic acid than hydrogenotrophic methanogenesis. Meanwhile, methanogenic microbial community changed significantly, and few species grew well under excessive organic loads. This study provides an attempt to reveal the mechanism of VFA inhibition in anaerobic digestion of kitchen wastes. PMID:24811447

Xu, Zhiyang; Zhao, Mingxing; Miao, Hengfeng; Huang, Zhenxing; Gao, Shumei; Ruan, Wenquan

2014-07-01

145

Preliminary evaluation of selected in situ remediation technologies for Volatile Organic Compound contamination at Arid sites  

SciTech Connect

To support the Volatile Organic Compounds-Arid Site (VOC-Arid) Integrated Demonstration (ID) in its technical, logistical, institutional, and economical testing of emerging environmental management and restoration technologies. Pacific Northwest Laboratory(a) is evaluating several in situ remediation technologies for possible inclusion in the demonstration. The evaluations are made with respect to the initial focus of the VOC-Arid ID: the carbon tetrachloride contamination at the Hanford Site, where it was disposed to the vadose zone along with other volatile and nonvolatile organic wastes. heavy metals, acids. and radionuclides. The purposes of this report are (1) to identify candidate in situ technologies for inclusion in the program, (2) to evaluate the candidate technologies based on their potential applicability to VOC contamination at arid sites and geologic conditions representative of the ID host site (i.e., Hanford Site), and (3) to prioritize those technologies for future US Department of Energy (DOE) support.

Lenhard, R.J.; Gerber, M.A.; Amonette, J.E.

1992-10-01

146

Analysis of organic volatile flavor compounds in fermented stinky tofu using SPME with different fiber coatings.  

PubMed

The organic volatile flavor compounds in fermented stinky tofu (FST) were studied using SPME-GC/MS. A total of 39 volatile compounds were identified, including nine esters, seven alcohols, five alkenes, four sulfides, three heterocycles, three carboxylic acids, three ketones, two aldehydes, one phenol, one amine and one ether. These compounds were determined by MS, and conformed by comparison of the retention times of the separated constituents with those of authentic samples and by comparison of retention indexes (RIs) of separated constituents with the RIs reported in the literature. The predominant volatile compound in FST was indole, followed by dimethyl trisulfide, phenol, dimethyl disulfide and dimethyl tetrasulfide. In order to find a better extraction time, the extraction times was optimized for each type of SPME fiber; the results show that the best extraction time for Carboxen/PDMS is 60 min, for PDMS/DVB 30 min, for DVB/CAR/PDMS 60 min and for PDMS 75 min. Of the four fibers used in this work, Carboxen/PDMS is found to be the most suitable to extract the organic volatile flavor compounds in fermented stinky tofu. PMID:22450681

Liu, Yuping; Miao, Zhiwei; Guan, Wei; Sun, Baoguo

2012-01-01

147

Volatile organic compound losses from sewage sludge-amended soils  

SciTech Connect

Volatile organic compounds (VOCs) applied to soil in sludge have been assumed to disappear quickly and completely. The VOC behavior in sludge-amended soils has been studied previously only in laboratory systems where the sludged soil has been spiked with compounds of interest. Behavior in these systems may not necessarily represent compound behavior in field soils to which contaminated sludge is added. A series of laboratory microcosm experiments were designed therefore to investigate the behavior of toluene, ethyl benzene, o-, m-, and p-xylene applied to soil in contaminated sludge, and factors influencing loss processes. The VOC loss from sludge-amended soil was well described by a simple one step pseudo-first-order model but in certain soils was better described by a two step first-order model. Volatilization was the predominant loss process. Rates of loss depended on sludge application rate, method of sludge application, soil properties, and on compound characteristics. Experiments indicated that spiking sludge-amended soils gave a reasonable indication of VOC loss rates from systems amended with contaminated sludge at least over a period of 23 d. The majority of VOCs applied to soils in sludge volatilizes quickly to the atmosphere over a few to 10s of days with a small fraction lost more slowly. Potential for VOC crop uptake, livestock ingestion, and contamination of ground water is low under routine, managed applications of sewage sludge to agricultural land.

Wilson, S.C.; Jones, K.C.

1999-08-01

148

Adsorption of selected volatile organic vapors on multiwall carbon nanotubes.  

PubMed

Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. This study examines the adsorption behaviors of volatile organic compounds (VOCs), n-hexane, benzene, trichloroethylene and acetone on two multiwall carbon nanotubes (MWCNTs), CNT1 and CNT2. Among these VOCs, acetone exhibits the highest adsorption capacity. The highest adsorption enthalpies and desorption energies of acetone were also observed. The strong chemical interactions between acetone and both MWCNTs may be the result from chemisorption on the topological defects. The adsorption heats of trichloroethylene, benzene, and n-hexane are indicative of physisorption on the surfaces of both MWCNTs. CNT2 presents a higher adsorption capacity than CNT1 due to the existence of an exterior amorphous carbon layer on CNT2. The amorphous carbon enhances the adsorption capacity of organic chemicals on carbon nanotubes. The morphological and structure order of carbon nanotubes are the primary affects on the adsorption process of organic chemicals. PMID:17980962

Shih, Yang-hsin; Li, Mei-syue

2008-06-15

149

Stability of volatile organics in environmental soil samples. Final report  

SciTech Connect

This report focuses on data generated for the purpose of establishing the stability of 19 volatile organic compounds in environmental soil samples. The study was carried out over a 56 day (for two soils) and a 111 day (for one reference soil) time frame and took into account as many variables as possible within the constraints of budget and time. The objectives of the study were: 1) to provide a data base which could be used to provide guidance on pre-analytical holding times for regulatory purposes; and 2) to provide a basis for the evaluation of data which is generated outside of the currently allowable holding times.

Maskarinec, M.P.; Bayne, C.K.; Jenkins, R.A.; Johnson, L.H.; Holladay, S.K.

1992-11-01

150

Stability of volatile organics in environmental soil samples  

SciTech Connect

This report focuses on data generated for the purpose of establishing the stability of 19 volatile organic compounds in environmental soil samples. The study was carried out over a 56 day (for two soils) and a 111 day (for one reference soil) time frame and took into account as many variables as possible within the constraints of budget and time. The objectives of the study were: 1) to provide a data base which could be used to provide guidance on pre-analytical holding times for regulatory purposes; and 2) to provide a basis for the evaluation of data which is generated outside of the currently allowable holding times.

Maskarinec, M.P.; Bayne, C.K.; Jenkins, R.A.; Johnson, L.H.; Holladay, S.K.

1992-11-01

151

Volatile fatty acids in the faeces of patients in 'germ-free' isolation.  

PubMed

Faecal volatile fatty acids represent the end products of the metabolism of the anaerobic flora of the large bowel. The excretion of these volatile acids has been investigated in five leukaemic patients maintained in plastic ;germ-free' isolators. Under ;isolator' conditions there is a pronounced fall in volatile fatty acid excretion. The possibility that the measurement of these acids may be used to monitor anaerobic overgrowth and recolonization in these patients is discussed. PMID:4512609

Gompertz, D; Brooks, A P; Gaya, H; Spiers, A S

1973-03-01

152

Meeting new air standards with a volatile organic treatment train  

SciTech Connect

The U.S. Environmental Protection Agency (EPA) issued the second phase of the organic air emission standards for hazardous waste treatment, storage, and disposal facilities (TSDFs) and hazardous waste generators in December 1994. These standards (referred to as the Subpart CC standards) are designed to further reduce organic air emissions from hazardous waste management activities. To comply with these new air standards, Lawrence Livermore National Laboratory (LLNL) is designing a volatile organic removal and destruction treatment train to modify its existing Waste Water Treatment Tank Farm (hereafter called Tank Farm). LLNL`s Tank Farm consists of six, 7,000-L open-top tanks used to store and treat aqueous low-level radioactive, mixed, and hazardous waste before discharging it to the local publicly owned treatment works. The waste stored and treated in the tanks have elevated volatile organic constituent (VOC) concentrations. According to the Subpart CC standards, tanks handling waste with similar VOC concentrations must be retrofitted with a cover and an emission control device for cover openings that achieves at least a 95% reduction in the total organic content of the vented gas stream. However, LLNL concluded that the removal and destruction of VOCs from waste before they enter the Tank Farm would demonstrate compliance with the Subpart CC standards more effectively and be more cost effective than installation of air emission control devices on the Tank Farm. LLNL has designed this removal and destruction technique to consist of an air stripper, high-efficiency particulate air (HEPA) filter, catalytic oxidizer, scrubber, and mist eliminator.

Bowers, J.S.; Dennison, D.; May, G.

1995-02-01

153

Evaporation of volatile organic compounds from human skin in vitro.  

PubMed

The specific evaporation rates of 21 volatile organic compounds (VOCs) from either human skin or a glass substrate mounted in modified Franz diffusion cells were determined gravimetrically. The diffusion cells were positioned either on a laboratory bench top or in a controlled position in a fume hood, simulating indoor and outdoor environments, respectively. A data set of 54 observations (34 skin and 20 glass) was assembled and subjected to a correlation analysis employing 5 evaporative mass transfer relationships drawn from the literature. Models developed by Nielsen et al. (Prediction of isothermal evaporation rates of pure volatile organic compounds in occupational environments: a theoretical approach based on laminar boundary layer theory. Ann Occup Hyg 1995;39:497-511.) and the U.S. Environmental Protection Agency (Peress, Estimate evaporative losses from spills. Chem Eng Prog 2003; April: 32-34.) were found to be the most effective at correlating observed and calculated evaporation rates under the various conditions. The U.S. EPA model was selected for further use based on its simplicity. This is a turbulent flow model based only on vapor pressure and molecular weight of the VOC and the effective air flow rate u. Optimum values of u for the two laboratory environments studied were 0.23 m s(-1) (bench top) and 0.92 m s(-1) (fume hood). PMID:23609116

Gajjar, Rachna M; Miller, Matthew A; Kasting, Gerald B

2013-08-01

154

Transport, behavior, and fate of volatile organic compounds in streams  

USGS Publications Warehouse

Volatile organic compounds (VOCs) are compounds with chemical and physical properties that allow the compounds to move freely between the water and air phases of the environment. VOCs are widespread in the environment because of this mobility. Many VOCs have properties that make them suspected or known hazards to the health of humans and aquatic organisms. Consequently, understanding the processes affecting the concentration and distribution of VOCs in the environment is necessary. The transport, behavior, and fate of VOCs in streams are determined by combinations of chemical, physical, and biological processes. These processes are volatilization, absorption, wet and dry deposition, microbial degradation, sorption, hydrolysis, aquatic photolysis, oxidation, chemical reaction, biocon-centration, advection, and dispersion. The relative importance of each of these processes depends on the characteristics of the VOC and the stream. The U.S. Geological Survey National Water-Quality Assessment Program selected 55 VOCs for study. This article reviews the characteristics of the various processes that could affect the transport, behavior, and fate of these VOCs in streams.

Rathbun, R. E.

2000-01-01

155

Removal of volatile organic compounds from air streams and industrial flue gases by non-thermal plasma technology  

Microsoft Academic Search

Gaseous pollution control technologies for acid gases (NOx , SOx, etc.), volatile organic compounds (VOC), greenhouse gases, ozone layer depleting substance (ODS), etc., have been commercialized based on catalysis, incineration and adsorption methods. However, non-thermal plasma techniques based on electron beams and corona discharges become significant due to advantages such as lower cost, higher removal efficiency, smaller space volume, etc.

Kuniko Urashima; Jen-Shih Chang

2000-01-01

156

Simultaneous analysis of phytohormones, phytotoxins, and volatile organic compounds in plants  

PubMed Central

Phytohormones regulate the protective responses of plants against both biotic and abiotic stresses by means of synergistic or antagonistic actions referred to as signaling crosstalk. A bottleneck in crosstalk research is the quantification of numerous interacting phytohormones and regulators. The chemical analysis of salicylic acid, jasmonic acid, indole-3-acetic acid, and abscisic acid is typically achieved by using separate and complex methodologies. Moreover, pathogen-produced phytohormone mimics, such as the phytotoxin coronatine (COR), have not been directly quantified in plant tissues. We address these problems by using a simple preparation and a GC-MS-based metabolic profiling approach. Plant tissue is extracted in aqueous 1-propanol and mixed with dichloromethane. Carboxylic acids present in the organic layer are methylated by using trimethylsilyldiazomethane; analytes are volatilized under heat, collected on a polymeric absorbent, and eluted with solvent into a sample vial. Analytes are separated by using gas chromatography and quantified by using chemical-ionization mass spectrometry that produces predominantly [M+H]+ parent ions. We use this technique to examine levels of COR, phytohormones, and volatile organic compounds in model systems, including Arabidopsis thaliana during infection with Pseudomonas syringae pv. tomato DC3000, corn (Zea mays) under herbivory by corn earworm (Helicoverpa zea), tobacco (Nicotiana tabacum) after mechanical damage, and tomato (Lycopersicon esculentum) during drought stress. Numerous complex changes induced by pathogen infection, including the accumulation of COR, salicylic acid, jasmonic acid, indole-3-acetic acid, and abscisic acid illustrate the potential and simplicity of this approach in quantifying signaling crosstalk interactions that occur at the level of synthesis and accumulation.

Schmelz, Eric A.; Engelberth, Juergen; Alborn, Hans T.; O'Donnell, Phillip; Sammons, Matt; Toshima, Hiroaki; Tumlinson, James H.

2003-01-01

157

Cyclodextrin-based microsensors for volatile organic compounds  

SciTech Connect

Host-guest chemistry and self-assembly techniques are being explored to develop species selective thin-films for real-time sensing of volatile organic compounds (VOCs). Cyclodextrin (CD) and calixarene (CA) molecules are known to form guest-host inclusion complexes with a variety of organic molecules. Through the control of the cavity size and chemical functionality on the rims of these bucket-like molecules, the binding affinities for formation of inclusion complexes can be controlled and optimized for specific agents. Self-assembly techniques are used to covalently bond these reagent molecules to the surface of acoustic transducers to create dense, highly oriented, and stable thin films. Self-assembly techniques have also been used to fabricate multilayer thin film containing molecular recognition reagents through alternating adsorption of charged species in aqueous solutions. Self-assembly of polymeric molecules of the SAW device was also explored for fabricating species selective interfaces.

Swanson, B.; Johnson, S.; Shi, J.; Yang, Xiaoguang

1997-10-01

158

Volatile organic compounds in Gulf of Mexico sediments  

SciTech Connect

Volatile organic compounds (VOC), concentrations and compositions were documented for estuarine, coastal, shelf, slope, and deep water sediments from the Gulf of Mexico. VOC were measured (detection limit >0.01 ppb) using a closed-loop stripping apparatus with gas chromatography (GC) and flame ionization, flame photometric, and mass spectrometric detectors. The five primary sources of Gulf of Mexico sediment VOC are: (1) planktonic and benthic fauna and flora; (2) terrestrial material from riverine and atmospheric deposition; (3) anthropogenic inputs: (4) upward migration of hydrocarbons; and (5) transport by bottom currents or slumping. Detected organo-sulfur compounds include alkylated sulfides, thiophene, alkylated thiophenes, and benzothiophenes. Benzothiophenes are petroleum related. Low molecular weight organo-sulfur compounds result from the biological oxidation of organic matter. A lack of organosulfur compounds in the reducing environment of the Orca Basin may result from a lack of free sulfides which are necessary for their production.

McDonald, T.J.

1988-01-01

159

Micrometeoritic contribution of volatile organics to Earth's upper atmosphere  

NASA Astrophysics Data System (ADS)

Each year, the Earth accretes 30 million kg of extraterrestrial material, mostly the form of large micrometeorites, 100µm in diameter. Earlier work by Kress, Cody, and Brownlee (2008) showed that volatile organics, including CH4 and small functionalized polycyclic aromatics, are released during conditions simulating atmospheric entry of particles in this size range. The physical appearance of large micrometeorites indicates that they have suffered strong heating during atmospheric entry. Their mass is large enough that they do not slow down until they have been subject to substantial drag forces. However, their sizes are small enough to ensure that they are completely melted and partially evaporated during this process. We will present the organic flux as a function of altitude due to large micrometeorites, and discuss the implications for the atmospheric chemistry of Earth at various epochs in time, starting with the cessation of heavy bombardment through the present day.

Pevyhouse, Alice; Kress, Monika; Iraci, Laura

160

Gas chromatography-mass spectrometry analysis of volatile organic compounds produced by some micromycetes  

Microsoft Academic Search

The volatile organic compounds evolved from various fungi were analyzed by gas chromatography-mass spectrometry. All the fungi studied were selected for their relevance in human mycology. According to their behaviour in the production of volatile compounds the fungi were divided into three groups. Group I was composed of fungi characteristically yeasts producing very high levels of volatile compounds. Ethanol, ethyl

A. Caileux; J. P. Bouchara; V. Daniel; D. Chabasse; P. Allain

1992-01-01

161

Contributions of Individual Biogenic Volatile Organic Compounds to Secondary Organic Aerosol and Organic Nitrate Formation above a Mixed Forest  

Microsoft Academic Search

Biogenic volatile organic compounds (BVOCs) are the largest source of atmospheric non-methane hydrocarbons globally. However, uncertainty remains in understanding the fate of BVOCs following emission. BVOCs can be oxidized to form secondary organic aerosol (SOA), CO, and CO2, or be removed from the atmosphere through dry and wet deposition. Further, the formation of organic nitrates through BVOC reaction with OH

K. A. Pratt; L. H. Mielke; P. B. Shepson; A. M. Bryan; A. L. Steiner; D. Helmig

2010-01-01

162

Air Quality in an Animal Facility: Particulates, Ammonia, and Volatile Organic Compounds  

Microsoft Academic Search

Concentrations of ammonia, volatile organic compounds, particles, and mouse allergen were measured in an animal facility. Ammonia concentrations averaged less than 1 ppm, below any health–based standards. The concentrations of volatile organic compounds were in the 5–15 µg\\/m range. Among the volatile organic compounds found, only the terpenes a–pinene and a–terpinol (which may be derived from the pine shavings used

Julie B. Kacergis; Robert B. Jones; Carolyn K. Reeb; William A. Turner; John L. Ohman; Margarett R. Ardman; Beverly Paigen

1996-01-01

163

Electrophysiological and behavioral responses of Thanatophilus sinuatus Fabricius (Coleoptera: Silphidae) to selected cadaveric volatile organic compounds.  

PubMed

Soon after death, carcasses release volatile chemicals that attract carrion insects including Silphidae. Nevertheless, it is not known which chemical cues are involved in the attractiveness of the carcass. So far, little information is available on the chemical ecology of carrion beetles, particularly concerning the subfamily of Silphinae. The biological role of selected cadaveric volatile organic compounds including dimethyldisulfide (DMDS), butan-1-ol, n-butanoic acid, indole, phenol, p-cresol, putrescine, and cadaverine on the silphine species, Thanatophilus sinuatus Fabricius, was investigated using both electrophysiological and behavioral techniques. Among the tested cadaveric compounds, butan-1-ol and DMDS elicited the strongest electroantennography (EAG) from both T. sinuatus male and female antennae. In a two-arm olfactometer, males and females were significantly attracted to DMDS for both tested doses, whereas only males were attracted to p-cresol at 100 ng. Putrescine was repellent to males at the dose of 1 ?g. PMID:23822801

Dekeirsschieter, Jessica; Frederickx, Christine; Lognay, Georges; Brostaux, Yves; Verheggen, Francois J; Haubruge, Eric

2013-07-01

164

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Volatile Organic HAP (VOHAP) Limits for Marine Coatings...2 to Subpart II of Part 63âVolatile Organic HAP (VOHAP) Limits for Marine Coatings... 728 Nuclear 420 841 1,069 Organic zinc 360 630 802...

2013-07-01

165

A luminescent mixed-lanthanide-organic framework sensor for decoding different volatile organic molecules.  

PubMed

A flexible tripodal polyaromatic acid (4,4',4?-(((2,4,6-trimethylbenzene-1,3,5-triyl)-tris(methylene))-tris(oxy))tribenzoic acid, H3TCM) was used to adapt the coordination sites of lanthanide ions for the construction of microporous lanthanide-organic frameworks (LOFs) [LnTCM(H2O)2]·3DMF·H2O (Ln-TCM; Ln = La, Eu, and/or Tb). In these LOFs, the emission band of TCM matches well with the excitation energy of lanthanide ions (Eu(3+) and Tb(3+)) which results in high-efficient resonance energy transfer from TCM to lanthanide ions. Moreover, the mixed EuxTb1-x-TCM has tunable pores to adapt different induced-fit-type host-guest interactions which can modulate both the energy transfer efficiency from TCM to Ln(3+) ions and the energy allocation between Eu(3+) and Tb(3+) ions in the luminescence spectra. We demonstrate that the EuxTb1-x-TCM sensor has the capability of decoding different volatile organic molecules (VOMs) with a clearly differentiable and unique emission intensity ratio of (5)D0 ? (7)F2 (Eu(3+), 614 nm) to (5)D4 ? (7)F5 (Tb(3+), 545 nm) transitions for every different VOM. Compared with the traditional absolute emission intensity method, such a self-referencing emission intensity strategy has generated self-calibrating, highly differentiable, and very stable luminescent signals for decoding different VOMs from the unique EuxTb1-x-TCM platform, which has great potential for practical applications. PMID:24892790

Zhan, Chao; Ou, Sha; Zou, Chao; Zhao, Min; Wu, Chuan-De

2014-07-01

166

User's Guide to the Collection and Analysis of Tree Cores to Assess the Distribution of Subsurface Volatile Organic Compounds.  

National Technical Information Service (NTIS)

Analysis of the volatile organic compound content of tree core is an inexpensive, rapid, simple approach to examining the distribution of subsurface volatile compound contaminants. The method has been shown to detect several volatile petroleum hydrocarbon...

D. A. Vroblesky

2008-01-01

167

A method for the combined measurement of volatile and condensable organic AMC in semiconductor applications  

NASA Astrophysics Data System (ADS)

Monitoring airborne molecular contamination (AMC) at the parts per trillion (ppt) level in cleanroom environments, scanner applications and compressed gas lines is essential for processes, equipment and yield-control. For the operation of EUV tools, in particular, volatile organic contamination is known to have as much impact as condensable organic compounds, which requires a suitable sampling and measurement methodology. Some of the current industry standards use sample traps comprised of porous 2,6-diphenylene-oxide polymer resin, such as Tenax®, for measuring volatile organic (<6 C-atoms, approximately IPA/acetone to toluene) and condensable organic (>6 C atoms, about toluene and higher) AMC. Inherent problems associated with these traps are a number of artifacts and chemical reactions that reduce accuracy of reported organic AMC concentrations. The break-down of the polymeric material forms false positive artifacts when used in the presence of reactive gases, such as nitrous acid and ozone, which attack and degrade the polymer to form detectable AMC. Most importantly, these traps have poor capture efficiency for volatile organic compounds (VOC). To address the disadvantages of polymer-based sample traps, we developed a method based on carbonaceous, multi-layered adsorbent traps to replace the 2,6-diphenylene-oxide polymer resin sample trap type. Along with the new trap's ability to retain volatile organics, the trap was found to provide artifact-free results. With industry trends towards detecting more contaminants while continuously reducing required reporting limits for those compounds, artifact-free and accurate detection of AMC is needed at the parts per quadrillion (ppq) level. The proposed, multi-layered trap substantially increases laboratory productivity and reduces cost by eliminating the need to analyze condensable and volatile organic compounds in two separate methods. In our studies, even some organic compounds with six C-atoms, that are part of exposure tool OEM requirements, were not effectively retained by polymeric traps, but were fully retained on the multi-layered adsorbent trap. This demonstrates that the standard trap used in the industry will result in significantly underreporting actual AMC concentrations for volatile organic compounds, including some siloxanes (TMS, HMDSO, D3). Performance of the proposed trap was excellent at both zero and 50% relative humidity, an important metric, as the trap is used for AMC detection in dry supply gases and humidified environments. Retention of all organic compounds was quantitative for more than 30 liters of air, sufficient for ppq-level detection limits. Desorption efficiency was 94% for C26 compounds. Pressure drop through the new trap was comparable to that of polymer-based traps and much lower than other, commercially available carbonaceous traps. Precision of repeated analyses was 5%, a very good result. Resolution of IPA and acetone was complete and that of a mix of halogenated refrigerants was much improved over existing methods. We propose to adopt this methodology as a new industry standard to overcome widespread inaccuracy in the reporting of volatile organic AMC and false positive condensable AMC.

Miller, Charles M.; Zaloga, Emily C.; Lobert, Jürgen M.

2014-04-01

168

[Effect of low-molecular-weight organic carbon on anaerobic degradation and volatilization of hexachlorobenzene in soils].  

PubMed

Batch incubation experiments in aid of anaerobic incubation flask were conducted to study the anaerobic degradation and volatilization of hexachlorobenzene (HCB), the change of pH in soil, the emission of CH4 and CO2, and the volatilization of HCB in the Hydragric Acrisol and Gleyi-Stagnic Anthrosol added with acetic acid, glucose and citric acid. Results showed that HCB was reduced by 20%-44% in Hydragric Acrisol during 8 weeks, and addition of acetic acid inhibited the dechlorination, indicating that dechlorination was impeded at low pH. Addition of glucose or citric acid decreased the dechlorination rate initially and then increased it. HCB was reduced by 21%-23% in Gleyi-Stagnic Anthrosol, and there was no obvious effect by adding low-molecular-weight organic carbon. The main product of HCB anaerobic dechlorination was pentachlorobenzene (PCB), which were 23-96 microg/kg and 64-92 microg/kg in Hydragric Acrisol and Gleyi-Stagnic Anthrosol respectively. Furthermore, the degradation of HCB had no statistically significant correlation with the productions of CH4 and CO2. Addition of low-molecular-weight organic carbon reduced HCB volatilization, which was stronger in Hydragric Acrisol than in Gleyi-Stagnic Anthrosol, indicating that soil organic matter was an important factor in HCB volatilization. PMID:18624217

Liu, Cui-Ying; Yu, Gui-Fen; Jiang, Xin; Wang, Tao

2008-05-01

169

Evaluation of volatile organic emissions from hazardous waste incinerators.  

PubMed Central

Conventional methods of risk assessment typically employed to evaluate the impact of hazardous waste incinerators on public health must rely on somewhat speculative emissions estimates or on complicated and expensive sampling and analytical methods. The limited amount of toxicological information concerning many of the compounds detected in stack emissions also complicates the evaluation of the public health impacts of these facilities. An alternative approach aimed at evaluating the public health impacts associated with volatile organic stack emissions is presented that relies on a screening criterion to evaluate total stack hydrocarbon emissions. If the concentration of hydrocarbons in ambient air is below the screening criterion, volatile emissions from the incinerator are judged not to pose a significant threat to public health. Both the screening criterion and a conventional method of risk assessment were employed to evaluate the emissions from 20 incinerators. Use of the screening criterion always yielded a substantially greater estimate of risk than that derived by the conventional method. Since the use of the screening criterion always yielded estimates of risk that were greater than that determined by conventional methods and measuring total hydrocarbon emissions is a relatively simple analytical procedure, the use of the screening criterion would appear to facilitate the evaluation of operating hazardous waste incinerators.

Sedman, R M; Esparza, J R

1991-01-01

170

Production of volatile organic sulfur compounds (VOSCs) by basidiomycetous yeasts.  

PubMed

Thirty-seven basidiomycetous yeasts belonging to 30 species of seven genera were grown on media containing l-cysteine or l-methionine as sole nitrogen sources with the objective of evaluating volatile organic sulfur compound (VOSC) production. The headspace of yeast cultures was analyzed by the solid-phase microextraction (SPME) sampling method, and volatile compounds were quantified and identified by GC-MS techniques. Ten strains assimilating L-methionine produced the following VOSCs: 3-(methylthio)-1-propanol, methanethiol, S-methyl thioacetate, dimethyl disulfide, dimethyl trisulfide, allyl methyl sulphide and 4,5-dihydro-3(2H)-thiophenone. Production was <1 mgl(-1) except for 3-(methylthio)-1-propanol of which between 40 and 400 mgl(-1) was synthesized. Higher alcohols (isobutyl alcohol, isoamyl alcohol and active amyl alcohol) and esters (ethyl acetate, ethyl propionate, n-propyl acetate, isobutyl acetate, n-propyl propionate, n-butyl acetate, isoamyl acetate, amyl acetate, isoamyl propionate, amyl propionate and 2-phenylmethyl acetate) were also sporadically produced. This is the first report of VOSCs production by basidiomycetous yeasts. Consequently, basidiomycetous yeasts may be considered an interesting new group of microbial VOSCs producers for the flavor industry. PMID:15691743

Buzzini, Pietro; Romano, Sergio; Turchetti, Benedetta; Vaughan, Ann; Pagnoni, Ugo Maria; Davoli, Paolo

2005-02-01

171

Maximization of volatile fatty acids production from alginate in acidogenesis.  

PubMed

In this study, the response surface methodology (RSM) was applied to determine the optimum fermentative condition of alginate with the respect to the simultaneous effects of alginate concentration and initial pH to maximize the production of total volatile fatty acids (TVFAs) and alcohols. The results showed that the alginate fermentation was significantly affected by initial pH than by alginate concentration and there was no interaction between the two variables. The optimum condition was 6.2g alginate/L and initial pH 7.6 with a maximum TVFAs yield of 37.1%. Acetic acids were the main constituents of the TVFAs mixtures (i.e., 71.9-95.5%), while alcohols (i.e., ethanol, butanol, and propanol) were not detected. PMID:24080441

Pham, Hong Duc; Seon, Jiyun; Lee, Seong Chan; Song, Minkyung; Woo, Hee-Chul

2013-11-01

172

Volatile Organic Compounds in Various Marine Organisms From the Southern North Sea  

Microsoft Academic Search

The concentration levels of 12 priority volatile organic compounds (VOCs) were determined in two species of vertebrates and four species of invertebrates from sampling stations in the southern North Sea, using a modified Tekmar LSC 2000 purge and trap system coupled to gas chromatograph–mass spectrometer (GC–MS). In general, concentration levels of VOCs found in this study were of the same

Patrick Roose; Udo A. Th Brinkman

2000-01-01

173

Volatile fatty acids distribution during acidogenesis of algal residues with pH control.  

PubMed

The anaerobic acidification of protein-rich algal residues with pH control (4, 6, 8, 10) was studied in batch reactors, which was operated at mesophilic(35 °C) condition. The distribution of major volatile fatty acids (VFAs) during acidogenesis was emphasized in this paper. The results showed that the acidification efficiency and VFAs distribution in the acid reactor strongly depended on the pH. The main product for all the runs involved acetic acid except that the proportion of butyric acid acidified at pH 6 was relatively higher. The other organic acids remained at lower levels. The VFAs yield reached the maximum value with about 0.6 g VFAs/g volatile solid (VS) added as pH was 8, and also the content of total ammonia nitrogen (TAN) reached the highest values of 9,629 mg/l. Low acidification degrees were obtained under the conditions at pH 4 and 10, which was not suitable for the metabolism of acidogens. Hydralic retention time (HRT) required for different conditions varied. As a consequence, it was indicated that pH was crucial to the acidification efficiency and products distribution. The investigation of acidogenesis process, which was producing the major substrates, short-chain fatty acids, would play the primary role in the efficient operation of methanogenesis. PMID:23381617

Li, Yan; Hua, Dongliang; Zhang, Jie; Zhao, Yuxiao; Xu, Haipeng; Liang, Xiaohui; Zhang, Xiaodong

2013-06-01

174

Oxidation of volatile organic compounds on AlâOâ, Pd\\/AlâOâ, and PdO\\/AlâOâ catalysts  

Microsoft Academic Search

Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study the decomposition and oxidation of methanol, ethanol, acetaldehyde, formic acid, and acetic acid on AlâOâ, Pd\\/AlâOâ, and PdO\\/AlâOâ catalysts. The oxidation and decomposition rates were much higher on Pd\\/AlâOâ than on AlâOâ, even though the volatile organic compounds (VOCs) were adsorbed on the AlâOâ support in both cases. The VOCs

E. Cordi; J. L. Falconer

1996-01-01

175

The effects of fungal volatile organic compounds on bone marrow stromal cells.  

PubMed

Evidence has shown that individuals exposed to indoor toxic molds for extended periods of time have elevated risk of developing numerous respiratory illnesses. It is not clear at the cellular level what impact mold exposure has on the immune system. Herein, we show that 2 fungal volatiles (E)-2-octenal and oct-1-en-3-ol have cytotoxic effects on murine bone marrow stromal cells. To further analyze alterations to the cell, we evaluated the impact these volatile organic compounds have on membrane composition and hence fluidity. Both (E)-2-octenal and oct-1-en-3-ol exposure caused a shift to unsaturated fatty acids and lower cholesterol levels in the membrane. This indicates that the volatile organic compounds under investigation increased membrane fluidity. These vast changes to the cell membrane are known to contribute to the breakdown of normal cell function and possibly lead to death. Since bone marrow stromal cells are vital for the appropriate development and activation of immune cells, this study provides the foundation for understanding the mechanism at a cellular level for how mold exposure can lead to immune-related disease conditions. PMID:24392920

Hokeness, Kirsten; Kratch, Jacqueline; Nadolny, Christina; Aicardi, Kristie; Reid, Christopher W

2014-01-01

176

Indoor Volatile Organic Compounds and Chemical Sensitivity Reactions  

PubMed Central

Studies of unexplained symptoms observed in chemically sensitive subjects have increased the awareness of the relationship between neurological and immunological diseases due to exposure to volatile organic compounds (VOCs). However, there is no direct evidence that links exposure to low doses of VOCs and neurological and immunological dysfunction. We review animal model data to clarify the role of VOCs in neuroimmune interactions and discuss our recent studies that show a relationship between chronic exposure of C3H mice to low levels of formaldehyde and the induction of neural and immune dysfunction. We also consider the possible mechanisms by which VOC exposure can induce the symptoms presenting in patients with a multiple chemical sensitivity.

Win-Shwe, Tin-Tin; Arashidani, Keiichi; Kunugita, Naoki

2013-01-01

177

Detection of volatile organic compounds using surface enhanced Raman scattering  

SciTech Connect

The authors present the detection of volatile organic compounds directly in their vapor phase by surface-enhanced Raman scattering (SERS) substrates based on lithographically-defined two-dimensional rectangular array of nanopillars. The type of nanopillars is known as the tapered pillars. For the tapered pillars, SERS enhancement arises from the nanofocusing effect due to the sharp tip on top. SERS experiments were carried out on these substrates using various concentrations of toluene vapor. The results show that SERS signal from a toluene vapor concentration of ppm level can be achieved, and the toluene vapor can be detected within minutes of exposing the SERS substrate to the vapor. A simple adsorption model is developed which gives results matching the experimental data. The results also show promising potential for the use of these substrates in environmental monitoring of gases and vapors.

Chang, A S; Maiti, A; Ileri, N; Bora, M; Larson, C C; Britten, J A; Bond, T C

2012-03-22

178

Exposure of humans to a volatile organic mixture. 2. Sensory  

SciTech Connect

Time-course functions for symptoms of the sick building syndrome were derived from 66 healthy males exposed to clean air and a volatile organic compound (VOC) mixture in separate sessions. The mixture contained 22 VOCs (25 mg/cu m total concentration) commonly found air-borne in new or recently renovated buildings. Subjects rated the intensity of perceived irritation, odor, and other variables before and twice during 2.75 hr exposure periods. Eye and throat irritation, headache, and drowsiness increased or showed no evidence of adaptation during exposure, whereas odor intensity decreased by 30%. These results indicate that irritation intensity and other symptoms are not related in any simple fashion to odor intensity, suggesting that the symptoms may not be a psychosomatic response to detection of an aversive odor. Instead, subthreshold levels of VOCs may interact additively or hyperadditively and stimulate trigeminal nerve receptors.

Hudnell, H.K.; Otto, D.A.; House, D.E.; Molhave, L.

1992-01-01

179

Composition of volatile organic compounds in flowers of Astragalus sahendi.  

PubMed

A hydrodistillation sampling method, coupled to gas chromatography-mass spectrometry, was used in monitoring the volatile organic compounds in flowers of Astragalus sahendi. Accordingly, a total of 48 compounds were recognised, which were united by their terpenoid or aliphatic skeletons and low molecular weight. Above all, the significant presence of some insect-favoured terpenoid compounds, such as farnesol, cis- and trans-geraniol, alpha-bisabolol, nerolidol isomer, alpha-terpineol, alpha-terpinolene and thymol was significant. These findings confer a better understanding of pollination processes in the giant genus Astragalus. Furthermore, the results add to an increasing quantity of data corroborating the ecologic and evolutionary correlation between the floral bioactive compounds of plant species and their special types of pollinators. PMID:20803377

Movafeghi, A; Delazar, A; Amini, M; Asnaashari, S; Nazifi, E

2010-09-01

180

Volatile organic components in the Skylab 4 spacecraft atmosphere  

NASA Technical Reports Server (NTRS)

The volatile organic components in the spacecraft cabin atmosphere of Skylab 4 were trapped on a solid adsorbent at various times during the mission. In post-flight analyses, more than 300 compounds in concentrations from less than 1 ppb up to 8000 ppb could be detected by high-resolution gas chromatography. In the samples of the 11th, 47th, and 77th day of the mission, approximately 100 components in the molecular weight range from 58 to 592 were identified by mass spectrometry. Besides components known from other environments, such as alkanes, alkenes, and alkylated aromatic hydrocarbons, components typical of the human metabolism, such as ketones and alcohols, were found. Other typical components in the spacecraft atmosphere included fluorocarbons and various silicone compounds, mostly normal and cyclic methylsiloxanes.

Liebich, H. M.; Bertsch, W.; Zlatkis, A.; Schneider, H. J.

1975-01-01

181

Adsorption of volatile organic compounds in porous metal–organic frameworks functionalized by polyoxometalates  

Microsoft Academic Search

The functionalization of porous metal–organic frameworks (Cu3(BTC)2) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N2 and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies

Feng-Ji Ma; Shu-Xia Liu; Da-Dong Liang; Guo-Jian Ren; Feng Wei; Ya-Guang Chen; Zhong-Min Su

2011-01-01

182

Arsenic speciation and volatilization from flooded paddy soils amended with different organic matters.  

PubMed

Arsenic (As) methylation and volatilization in soil can be increased after organic matter (OM) amendment, though the factors influencing this are poorly understood. Herein we investigate how amended OM influences As speciation as well as how it alters microbial processes in soil and soil solution during As volatilization. Microcosm experiments were conducted on predried and fresh As contaminated paddy soils to investigate microbial mediated As speciation and volatilization under different OM amendment conditions. These experiments indicated that the microbes attached to OM did not significantly influence As volatilization. The arsine flux from the treatment amended with 10% clover (clover-amended treatment, CT) and dried distillers grain (DDG) (DDG-amended treatment, DT2) were significantly higher than the control. Trimethylarsine (TMAs) was the dominant species in arsine derived from CT, whereas the primary arsine species from DT2 was TMAs and arsine (AsH(3)), followed by monomethylarsine (MeAsH(2)). The predominant As species in the soil solutions of CT and DT2 were dimethylarsinic acid (DMAA) and As(V), respectively. OM addition increased the activities of arsenite-oxidizing bacteria (harboring aroA-like genes), though they did not increase or even decrease the abundance of arsenite oxidizers. In contrast, the abundance of arsenate reducers (carrying the arsC gene) was increased by OM amendment; however, significant enhancement of activity of arsenate reducers was observed only in CT. Our results demonstrate that OM addition significantly increased As methylation and volatilization from the investigated paddy soil. The physiologically active bacteria capable of oxidization, reduction, and methylation of As coexisted and mediated the As speciation in soil and soil solution. PMID:22295880

Huang, Hai; Jia, Yan; Sun, Guo-Xin; Zhu, Yong-Guan

2012-02-21

183

Volatile organic compounds in storm water from a parking lot  

USGS Publications Warehouse

A mass balance approach was used to determine the most important nonpoint source of volatile organic compounds (VOCs) in storm water from an asphalt parking lot without obvious point sources (e.g., gasoline stations). The parking lot surface and atmosphere are important nonpoint sources of VOCs, with each being important for different VOCs. The atmosphere is an important source of soluble, oxygenated VOCs (e.g., acetone), and the parking lot surface is an important source for the more hydrophobic VOCs (e.g., benzene). VOCs on the parking lot surface appear to be concentrated in oil and grease and organic material in urban particles (e.g., vehicle soot). Except in the case of spills, asphalt does not appear to be an important source of VOCs. The uptake isotherm of gaseous methyl tert-butyl ether on urban particles indicates a mechanism for dry deposition of VOCs from the atmosphere. This study demonstrated that a mass balance approach is a useful means of understanding non-point-source pollution, even for compounds such as VOCs, which are difficult to sample.A mass balance approach was used to determine the most important nonpoint source of volatile organic compounds (VOCs) in storm water from an asphalt parking lot without obvious point sources (e.g., gasoline stations). The parking lot surface and atmosphere are important nonpoint sources of VOCs, with each being important for different VOCs. The atmosphere is an important source of soluble, oxygenated VOCs (e.g., acetone), and the parking lot surface is an important source for the more hydrophobic VOCs (e.g., benzene). VOCs on the parking lot surface appear to be concentrated in oil and grease and organic material in urban particles (e.g., vehicle soot). Except in the case of spills, asphalt does not appear to be an important source of VOCs. The uptake isotherm of gaseous methyl tert-butyl ether on urban particles indicates a mechanism for dry deposition of VOCs from the atmosphere. This study demonstrated that a mass balance approach is a useful means of understanding non-point-source pollution, even for compounds such as VOCs, which are difficult to sample.

Lopes, T. J.; Fallon, J. D.; Rutherford, D. W.; Hiatt, M. H.

2000-01-01

184

Soil Samplers: New Techniques for Subsurface Sampling for Volatile Organic Compounds  

Microsoft Academic Search

Soil sampling techniques for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from the soil that is being sampled. Preventing VOC loss from soil cores that are collected from the subsurface and brought to the surface for subsampling is often difficult. Subsurface bulk sample retrieval systems are designed to obtain intact cylindrical cores of

Susan Sorini; John Schabron; Joseph Rovani; Mark Sanderson

2009-01-01

185

Removal of volatile and semivolatile organic contamination from soil by air and steam flushing  

Microsoft Academic Search

A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal

Brent E. Sleep; Paul D. McClure

2001-01-01

186

National Ambient Volatile Organic Compounds (VOCS) data base, 1970-1987 (for microcomputers), Data file  

Microsoft Academic Search

The National Ambient Volatile Organic Compounds (VOCs) Data Base update is the result of an ongoing effort to gather, evaluate, and compile the measured concentrations of a large number of VOCs. Data on the observed concentrations of 320 volatile organic compounds (VOCs) were compiled, critically evaluated, and assembled into a relational data base. Ambient (outdoor) measurements, indoor data, and data

J. J. Shah; L. T. Cupitt

1987-01-01

187

Closed cycle cooler for VOC preconcentration. Final report. [VOC (volatile organic compound)  

Microsoft Academic Search

The use of automated gas chromatographs at air quality network monitoring stations to obtain measurements of ambient concentrations of volatile organic compounds (VOCs) has been a goal of EPA's Atmospheric Research and Exposure Assessment Laboratory. Presently, instrument designs require excessive amounts of cryogen to preconcentrate and resolve the more volatile organic compounds. The large consumption of cryogen becomes a major

1993-01-01

188

Characterization of microbial species in a regenerative bio-filter system for volatile organic compound removal  

Microsoft Academic Search

Effective removal of volatile organic compounds is critical for indoor air quality control. The performance of traditional technologies of volatile organic compound removal is limited by inadequate selection of filter media, poor airflow management inside the cleaning devices, insufficient catalytic reaction surface area, and poor distribution of UV light irradiation. In comparison, the relatively new regenerative air filtration systems use

Wen-Hsuan Huang; Zhiqiang Wang; Geetika Choudhary; Beverly Guo; Jianshun Zhang; Dacheng Ren

2012-01-01

189

Ion-trap detection of volatile organic compounds in alveolar breath  

Microsoft Academic Search

We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated

M. Phillips; J. Greenberg

1992-01-01

190

Chlorinated Volatile Organic Compounds—Old, However, Actual Analytical and Toxicological Problem  

Microsoft Academic Search

The interest in chlorinated volatile organic compounds is not a new task but still draws the attention of scientists. The role they play in human organism, is an important aspect to consider, since the development of analytical techniques and instrumental solutions gives new possibilities of their application in the analytics of volatile compounds and recognition of properties, so far impossible

El?bieta Dobrzy?ska; Ma?gorzata Po?niak; Ma?gorzata Szewczy?ska; Bogus?aw Buszewski

2010-01-01

191

ASSESSMENT OF VOLATILE ORGANIC EMISSIONS FROM A PETROLEUM REFINERY LAND TREATMENT SITE  

EPA Science Inventory

A field assessment was performed to measure the emissions of volatile organics from a petroleum refinery landtreatment site. As part of the study, the emissions of total volatile organics from surface-applied and subsurface-injected oily sludge were measured over a five week peri...

192

40 CFR 60.542a - Alternate standard for volatile organic compounds.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Alternate standard for volatile organic compounds. 60.542a Section 60.542a Protection of...Manufacturing Industry § 60.542a Alternate standard for volatile organic compounds. (a) On and after the date on which...

2013-07-01

193

A survey of household products for volatile organic compounds  

NASA Astrophysics Data System (ADS)

A total of 1159 common household products were analysed for 31 volatile organic compounds as potential sources of indoor air pollution. The products were distributed among 65 product categories within 8 category classes: automotive products (14.4% of the products); household cleaners/polishes (9.6%); paint-related products (39.9%); fabric and leather treatments (7.9%); cleaners for electronic equipment (6.0%); oils, greases and lubricants (9.6%); adhesive-related products (6.6%); and miscellaneous products (6.1%). The study was conducted in two parts. In the first part, or the original study, the products were reanalysed for methylene chloride and five other chlorocarbons using purge-and-trap gas chromatography/mass spectrometry (GC/MS), and a data base containing the analytical results was developed. Because full mass spectra were taken, the original set of GC/MS data also contained information regarding other volatile chemicals in the products. However, this additional data was not reported at that time. In the second part of the study, the GC/MS data were reanalysed to determine the presence and concentrations of an additional 25 volatile chemicals. The 31 chemicals included in both parts of this study were: carbon tetrachloride; methylene chloride; tetrachloroethylene; 1,1,1-trichloroethane; trichlorethylene; 1,1,2-tricholorotrifluoroethane; acetone; benzene; 2-butanone; chlorobenzene; chloroform; cyclohexane; 1,2-dichloroethane; 1,4-dioxane; ethylbenzene; n-hexane; d-limonene; methylcyclohexane; methylcyclopentane; methyl isobutyl ketone; n-nonane; n-octane; ?-pinene; propylene oxide; styrene; 1,1,2,2-tetrachloroethane; tetrahydrofuran; toluene; m-mxylene; o-xylene; and p-xylene. Of the 31 chemicals, toluene, the xylenes and methylene chloride were found to occur most frequently—in over 40% of the products tested. Chemicals that were typically found in relatively high concentrations in the samples (i.e. greater than 20% w/w) included acetone, 2-butanone, hexane, methylene chloride, tetrachloroethylene, toluene, 1,1,1-trichloroethane, trichloroethylene, 1,1,2-trichlorotrifluoroethane and the xylenes. Chlorobenzene, d-limonene, 1,1,2,2-tetrachloroethane, n-nonane and styrene were not found in any of the products at or above the 0.1% level. In all, 935 of the products contained one or more of the target solvents at levels greater than 0.1%. The resulting data base contains information regarding the 1159 products, such as origin, cost, container type, lot number, etc., as well as quantitative information for each of the 31 chemicals. The frequency of occurrence and average concentrations for the target chemicals are summarized for each of the product classes.

Sack, Thomas M.; Steele, David H.; Hammerstrom, Karen; Remmers, Janet

194

Qualitative analysis of volatile organic compounds on biochar.  

PubMed

Qualitative identification of sorbed volatile organic compounds (VOCs) on biochar was conducted by headspace thermal desorption coupled to capillary gas chromatographic-mass spectrometry. VOCs may have a mechanistic role influencing plant and microbial responses to biochar amendments, since VOCs can directly inhibit/stimulate microbial and plant processes. Over 70 biochars encompassing a variety of parent feedstocks and manufacturing processes were evaluated and were observed to possess diverse sorbed VOC composition. There were over 140 individual chemical compounds thermally desorbed from some biochars, with hydrothermal carbonization (HTC) and fast pyrolysis biochars typically possessing the greatest number of sorbed volatiles. In contrast, gasification, thermal or chemical processed biochars, soil kiln mound, and open pit biochars possessed low to non-detectable levels of VOCs. Slow pyrolysis biochars were highly variable in terms of their sorbed VOC content. There were no clear feedstock dependencies to the sorbed VOC composition, suggesting a stronger linkage with biochar production conditions coupled to post-production handling and processing. Lower pyrolytic temperatures (?350°C) produced biochars with sorbed VOCs consisting of short carbon chain aldehydes, furans and ketones; elevated temperature biochars (>350°C) typically were dominated by sorbed aromatic compounds and longer carbon chain hydrocarbons. The presence of oxygen during pyrolysis also reduced sorbed VOCs. These compositional results suggest that sorbed VOCs are highly variable and that their chemical dissimilarity could play a role in the wide variety of plant and soil microbial responses to biochar soil amendment noted in the literature. This variability in VOC composition may argue for VOC characterization before land application to predict possible agroecosystem effects. PMID:21788060

Spokas, Kurt A; Novak, Jeffrey M; Stewart, Catherine E; Cantrell, Keri B; Uchimiya, Minori; Dusaire, Martin G; Ro, Kyoung S

2011-10-01

195

Neurotoxicity of fungal volatile organic compounds in Drosophila melanogaster.  

PubMed

Many volatile organic compounds (VOCs) are found in indoor environment as products of microbial metabolism. In damp indoor environments, fungi are associated with poor air quality. Some epidemiological studies have suggested that microbial VOCs have a negative impact on human health. Our study was designed to provide a reductionist approach toward studying fungal VOC-mediated toxicity using the inexpensive model organism, Drosophila melanogaster, and pure chemical standards of several important fungal VOCs. Low concentrations of the following known fungal VOCs, 0.1% of 1-octen-3-ol and 0.5% of 2-octanone; 2,5 dimethylfuran; 3-octanol; and trans-2-octenal, caused locomotory defects and changes in green fluorescent protein (GFP)- and antigen-labeled dopaminergic neurons in adult D. melanogaster. Locomotory defects could be partially rescued with L-DOPA. Ingestion of the antioxidant, vitamin E, improved the survival span and delayed the VOC-mediated changes in dopaminergic neurons, indicating that the VOC-mediated toxicity was due, in part, to generation of reactive oxygen species. PMID:20643751

Inamdar, Arati A; Masurekar, Prakash; Bennett, Joan Wennstrom

2010-10-01

196

[Research advances on volatile organic compounds emission inventory of plants].  

PubMed

Reference to relative literatures in recent years, model building and calculation on volatile organic compound (VOC) emission inventory of plants were summarized in different spatial scales, the total annual VOC emission amounts from Vegetation in China are in the range from 12.4 Tg x a(-1) to 28.4 Tg x a(-1). For garden plants in Beijing, the annual VOC emissions are approximately 38 500 tons C in 2000. Furthermore, in order to determine reduction strategies for Beijing urban atmospheric major pollutants, the contribution of garden plant VOC emissions to the ozone and secondary organic aerosol (SOA) formation was presented, compared to garden plant in the same period, the largest contribution to ozone formation comes from aromatic hydrocarbons and olefin which are exhausted from anthropogenic activity, besides, the aromatic hydrocarbons exhausted from anthropogenic activity is also a main contribution source for the potential formation of SOA. In the meantime, it is suggested to focus on emission control of VOCs which are emitted from urban anthropogenic sources. PMID:24640923

Xie, Jun-Fei; Li, Yan-Ming

2013-12-01

197

Identification of Volatile Hydrocarbons as Mobile Source Tracers for Fine-Particulate Organics.  

National Technical Information Service (NTIS)

Several volatile organic compounds (VOCs) have been identified as candidates for tracers of fine particulate carbon and Extractable Organic Matter (EOM) from mobile sources. The identification resulted from a multiple screening procedure in which the ambi...

R. B. Zweidinger R. K. Stevens C. W. Lewis H. Westburg

1990-01-01

198

EVALUATION OF THE WALKTHROUGH SURVEY METHOD FOR DETECTION OF VOLATILE ORGANIC COMPOUND LEAKS  

EPA Science Inventory

During 1978 and 1979, the Emission Standards and Engineering Division of EPA's Office of Air Quality Planning and Standards conducted a fugitive volatile organic compound (VOC) emission sampling program in organic chemical manufacturing plants and petroleum refineries. As a part ...

199

Alternatives to Automotive Consumer Products That Use Volatile Organic Compounds (VOC) and/or Chlorinated Organic Compound Solvents. Addendum.  

National Technical Information Service (NTIS)

This addendum to the document entitled 'Alternatives to Automotive Consumer Products that use Volatile Organic Compounds (VOC) and/or Chlorinated Organic Compound Solvents' presents the questionnaires that were filled out by the staff of the Institute for...

D. Wolf J. Zavadil M. Morris

2004-01-01

200

Recovery of Principal Organic Hazardous Constituents and Products of Incomplete Combustion from a Volatile Organic Sampling Train.  

National Technical Information Service (NTIS)

The report describes an investigation of the recovery efficiencies of selected principal organic hazardous constituents (POHCs) from the Volatile Organic Sampling Train (VOST) under laboratory conditions. The compounds included: vinyl chloride, carbon tet...

E. V. Robb J. F. McGaughey A. L. Sykes D. E. Wagoner

1986-01-01

201

Analysis of low- and non-volatile organic substances in the environment  

SciTech Connect

Three analytical techniques were utilized for the analysis of low- and non-volatile organic materials in various environmental samples. Gas chromatography-mass spectrometry was used to characterize lipid materials extracted from atmospheric aerosol samples collected over the equatorial Pacific ocean. Although terrestrial-derived lipids were present, the major source of the aerosol lipids appeared to be local marine sources whereas previous reports of non-equatorial Pacific ocean aerosols indicated a major terrestrial source of lipids. A supercritical fluid chromatograph (SFC), with flame ionization and mass spectrometric detectors, was constructed for analysis of compound mixtures which could not be adequately separated by gas chromatography or liquid chromatography. One such application was the separation and quantitation of glycerol tetraether lipids of archaebacteria. A new theory of solute retention in SFC, in which entropy changes play a significant role, was also developed. Pattern recognition procedures were applied to pyrolysis-mass spectrometry (Py-MS) data for the characterization of complex non-volatile organic mixtures. In one study, Py-MS data were used to distinguish humic acids from fulvic acids in a varied suite of humic materials. Another Py-MS study involved the classification of southeast Asian environmental samples associated with yellow rain. The method classified samples as either pollen or bee feces with a 95% success rate.

DeLuca, S.J.

1986-01-01

202

Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.  

PubMed

The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain. PMID:19376463

Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

2009-06-01

203

Organic Acids by Ion Chromatography  

NASA Astrophysics Data System (ADS)

The presence of increased levels of various organic acids in physiological fluids such as serum, plasma, and urine has been correlated with a variety of diseases (1). Although some are rare, others such as lactic acidosis and hyperoxaluria are more widespread (2, 3). The estimation of organic acids in biological fluids has long been an analytical problem owing to the nature of the samples and the hydrophilic behavior of the various acids.

Rich, William E.; Johnson, Edward; Lois, Louis; Stafford, Brian E.; Kabra, Pokar M.; Marton, Laurence J.

204

A new approach to estimating the volatilization rates of shower water-contained volatile organic compounds during showering  

Microsoft Academic Search

A mathematical hybrid-showering model was developed in order to describe the dynamic behaviour of volatile organic compounds (VOCs) contained in shower water during personal showering. The approach involves assuming a two-film theory and taking into account the dual flow patterns of “jet” and “spray” from a showerhead in order to estimate the emission of VOCs from tap water to air.

M. J. Chen; K. Y. Wu; L. Chang

2003-01-01

205

Compositing water samples for analysis of volatile organic compounds  

USGS Publications Warehouse

Accurate mean concentrations of volatile organic compounds (VOCs) can easily and economically be obtained from a single VOC analysis by using proven methods of collecting representative, discrete water samples and compositing them with a gas-tight syringe. The technique can be used in conjunction with chemical analysis by a conventional laboratory, field-portable equipment, or a mobile laboratory. The type of mean concentration desired depends on the objectives of monitoring. For example, flow-weighted mean VOC concentrations can be used to estimate mass loadings in wastewater and urban storm water, and spatially integrated mean VOC concentrations can be used to assess sources of drinking water (e.g., reservoirs and rivers). The mean error in a discrete sample due to compositing is about 2% for most VOC concentrations greater than 0.1 ??g/L. The total error depends on the number of discrete samples comprising the composite sample and precision of the chemical analysis.Accurate mean concentrations of volatile organic compounds (VOCs) can easily and economically be obtained from a single VOC analysis by using proven methods of collecting representative, discrete water samples and compositing them with a gas-tight syringe. The technique can be used in conjunction with chemical analysis by a conventional laboratory, field-portable equipment, or a mobile laboratory. The type of mean concentration desired depends on the objectives of monitoring. For example, flow-weighted mean VOC concentrations can be used to estimate mass loadings in wastewater and urban storm water, and spatially integrated mean VOC concentrations can be used to assess sources of drinking water (e.g., reservoirs and rivers). The mean error in a discrete sample due to compositing is about 2% for most VOC concentrations greater than 0.1 ??g/L. The total error depends on the number of discrete samples comprising the composite sample and precision of the chemical analysis.Researchers are able to derive accurate values for the mean concentration of VOCs from a single VOC analysis using established techniques for the collection of representative, discrete water samples. Such samples are then composited with a gas-tight syringe. This methodology can be employed in conjunction with chemical assessment using a conventional laboratory, field-portable equipment, or a mobile laboratory. Estimates of mass loadings in wastewater and urban storm runoff can be generated using values for the flow-weighted mean VOC concentrations. Spatially integrated mean VOC concentrations are useful for the evaluation of drinking waters. Factors that influence the value for the total error are identified.

Lopes, T. J.; Fallon, J. D.; Maluk, T. L.

2000-01-01

206

Role of volatile fatty acids in colonization resistance to Clostridium difficile.  

PubMed Central

The in vitro inhibition of Clostridium difficile by volatile fatty acids was correlated with the pH and concentrations of volatile fatty acids in the ceca of hamsters of different ages. The concentrations of cecal volatile fatty acids increased with the age of the animals. Maximum concentrations of individual volatile fatty acids were attained when the animals were ca. 19 days old, with acetic, propionic, and butyric acids occurring in the highest concentrations (72, 16, and 32 microequivalents/g of cecum, respectively). The cecal pH was approximately the same in hamsters of all ages (pH 6.6 to 7.0). Only butyric acid reached a concentration in the ceca of hamsters which was inhibitory to the in vitro multiplication of C. difficile. This inhibitory concentration was attained when the animals were ca. 19 days of age. When mixtures of volatile fatty acids were prepared at concentrations equal to those present in the ceca of hamsters, there was a direct correlation between the in vitro inhibitory activity of the volatile fatty acids and the susceptibility of hamsters 4 days of age or older to C. difficile intestinal colonization. The resistance of hamsters less than 4 days of age to C. difficile intestinal colonization appears to be due to factors other than volatile fatty acids.

Rolfe, R D

1984-01-01

207

Secondary Organic Aerosols Formed from Photooxidation of Biogenic Volatile Organic Compounds in Forests  

Microsoft Academic Search

Photooxidation products of biogenic volatile organic compounds were characterized and measured in PM2.5 (particulate matter with an aerodynamic diameter les2.5 mum aerosol samples from forests. Aerosol sampling was conducted at four sites centred in and around major research stations located in four different regions of China: Xiaoxing'an Ling (boreal), Dongping national forest park (temperate), Dinghu mountain (subtropical) and Wuzhi mountain

Wang Wu; Zhang Ting

2008-01-01

208

Analysis of Organic Acids.  

ERIC Educational Resources Information Center

Presented are the procedures and a discussion of the results for an experiment in which students select unknown carboxylic acids, determine their melting points, and investigate their solubility behavior in water and ethanol. A table of selected carboxylic acids is included. (CW)

Griswold, John R.; Rauner, Richard A.

1990-01-01

209

Volatile organic compounds in selected micro-environments.  

PubMed

A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds, 26 VOCs were detected in the samples collected. The highest concentrations were recorded for benzene, toluene, ethylbenzene, xylenes (BTEX), chloroform and styrene. The maximum 12-h toluene and benzene concentrations observed were from a basement carpark and were 24.7 parts per billion (ppb) and 5.6 ppb, respectively. The maximum xylenes concentration was 29.4 ppb and occurred in a nightclub where styrene was also detected. A factor analysis of the data was undertaken. Two key factors emerge that appear to be associated with petroleum and motor vehicles and environmental tobacco smoke. A third significant occurrence was a high concentration of chloroform that was observed at a sports centre complex with a swimming pool text and was uncorrelated with other compounds in the data set. This study indicates that locations associated with motor vehicles and petrol fuel, tobacco and wood smoke and chlorinated water represent the major risks for personal exposure to VOCs in Perth. PMID:16289288

Hinwood, A L; Berko, H N; Farrar, D; Galbally, I E; Weeks, I A

2006-04-01

210

Proton Transfer Rate Coefficient Measurements of Selected Volatile Organic Molecules  

NASA Astrophysics Data System (ADS)

We have developed an apparatus based on the selected ion flow tube (SIFT)footnote D. Smith and N.G. Adams, Ads. At. Mol. Phys. 24, 1 (1987). that allows the study of proton transfer between various positive ions and volatile organic molecules. Reactions in the flow tube occur at pressures of approximately 300 mTorr, eliminating the requirement of thermal beam production. The proton donor molecule H_3O^+ has been produced using several types of electrical discharges in water vapor, such as a capacitively coupled RF discharge and a DC hollow cathode discharge. Presently we are developing an Asmussen-type microwave cavity discharge using the components of a standard microwave oven that has the advantages of simple design and operation, as well as low cost. We will be presenting the results of the microwave cavity ion source to produce H_3O^+, and compare it to the other studied sources. In addition, we will be presenting a preliminary measurement of the proton transfer rate coefficient in the reaction of H_3O^+ with acetone and methanol.

Brooke, G.; Popovi?, S.; Vuškovi?, L.

2002-05-01

211

[Volatile organic compounds (VOCs) emitted from large furniture].  

PubMed

Indoor air pollution by volatile organic compounds (VOCs), which may cause a hazardous influence on human being such as sick building (sick house) syndrome, has become a serious problem. In this study, VOCs emitted from nine pieces of home furniture, three sets of dining tables, three sets of chest of drawers and three sofas, were analyzed as potential sources of indoor air pollution by large chamber test method (JIS A 1911). Based on the emission rates of total VOC (TVOC), the impacts on the indoor TVOC was estimated by the sample model with a volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in three sets of dining tables, one set of chest of drawer and one sofa. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table, two sets of chest of drawers and one sofa. These results revealed that VOC emissions from 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 three parts of furniture unit were evaluated using the small chamber and emission rate from full-sized furniture was predicted. Emission rates of TVOC and formaldehyde predicted by small chamber test were 3-46% and 6-252% of the data obtained using large chamber test, respectively. PMID:22259846

Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Jinno, Hideto; Nishimura, Tetsuji

2011-01-01

212

Sources of volatile organic compounds in Cairo's ambient air.  

PubMed

The greater Cairo area suffers from extreme levels of gas and particulate phase air pollutants. In order to reduce the levels of ambient pollution, the USAID and the Egyptian Environmental Affairs Agency (EEAA) have supported the Cairo Air Improvement Project (CAIP). As part of this project, two intensive ambient monitoring studies were carried out during the period of February 22 to March 4 and October 27 to November 27, 1999. Volatile organic compounds (VOCs) were measured on a 24-h basis at six sampling stations during each of the intensive periods. During the February/March study, samples were collected daily, while in the October/November study samples were collected every other day. The six intensive measurement sites represented background levels, mobile source impacts, industrial impacts, and residential exposure. High levels of NMHC were observed at all locations. NMHC concentrations ranged from 365 ppb C at Helwan to 1,848 ppb C at El Qualaly during winter, 1999 and from 461 ppb C at Kaha to 2,037 ppb C at El Qualaly during fall, 1999. El Qualaly, the site chosen to represent mobile emissions, displayed the highest average NMHC concentrations of any site, by a factor of 2 or more. The highest mobile source contributions were estimated at this site. The major contributors to NMHC at all sites were mobile emissions, lead smelting, and compressed natural gas. PMID:18843549

Abu-Allaban, M; Lowenthal, D H; Gertler, A W; Labib, M

2009-10-01

213

Measurements of volatile organic compounds over West Africa  

NASA Astrophysics Data System (ADS)

In this paper we describe measurements of volatile organic compounds (VOCs) made using a Proton Transfer Reaction Mass Spectrometer (PTR-MS) aboard the UK Facility for Atmospheric Airborne Measurements during the African Monsoon Multidisciplinary Analyses (AMMA) campaign. Observations were made during approximately 85 h of flying time between 17 July and 17 August 2006, above an area between 4° N and 18° N and 3° W and 4° E, encompassing ocean, mosaic forest, and the Sahel desert. High time resolution observations of counts at mass to charge (m/z) ratios of 42, 59, 69, 71, and 79 were used to calculate mixing ratios of acetonitrile, acetone, isoprene, the sum of methyl vinyl ketone and methacrolein, and benzene, respectively using laboratory-derived humidity-dependent calibration factors. Strong spatial associations between vegetation and isoprene and its oxidation products were observed in the boundary layer, consistent with biogenic emissions followed by rapid atmospheric oxidation. Acetonitrile, benzene, and acetone were all enhanced in airmasses which had been heavily influenced by biomass burning. Benzene and acetone were also elevated in airmasses with urban influence from cities such as Lagos, Cotonou, and Niamey. The observations provide evidence that both deep convection and mixing associated with fair-weather cumulus were responsible for vertical redistribution of VOCs emitted from the surface. Profiles over the ocean showed a depletion of acetone in the marine boundary layer, but no significant decrease for acetonitrile.

Murphy, J. G.; Oram, D. E.; Reeves, C. E.

2010-02-01

214

Measurements of volatile organic compounds over West Africa  

NASA Astrophysics Data System (ADS)

In this paper we describe measurements of volatile organic compounds (VOC) made using a Proton Transfer Reaction Mass Spectrometer (PTR-MS) aboard the UK Facility for Atmospheric Airborne Measurements during the African Monsoon Multidisciplinary Analyses (AMMA) campaign. Observations were made during approximately 85 h of flying time between 17 July and 17 August 2006, above an area between 4° N and 18° N and 3° W and 4° E, encompassing ocean, mosaic forest, and the Sahel desert. High time resolution observations of counts at mass to charge (m/z) ratios of 42, 59, 69, 71, and 79 were used to calculate mixing ratios of acetonitrile, acetone, isoprene, the sum of methyl vinyl ketone and methacrolein, and benzene respectively using laboratory-derived humidity-dependent calibration factors. Strong spatial associations between vegetation and isoprene and its oxidation products were observed in the boundary layer, consistent with biogenic emissions followed by rapid atmospheric oxidation. Acetonitrile, benzene, and acetone were all enhanced in airmasses which had been heavily influenced by biomass burning. Benzene and acetone were also elevated in airmasses with urban influence from cities such as Lagos, Cotonou, and Niamey. The observations provide evidence that both deep convection and mixing associated with fair-weather cumulus were responsible for vertical redistribution of VOC emitted from the surface. Profiles over the ocean showed a depletion of acetone in the marine boundary layer, but no significant decrease for acetonitrile.

Murphy, J. G.; Oram, D. E.; Reeves, C. E.

2010-06-01

215

Solid State Gas Sensor for Volatile Organic Vapours  

NASA Astrophysics Data System (ADS)

Nano Crystalline ZnO powders were synthesized by a Solvothermal method using propan-1ol as the reaction medium. Wurtzite-type ZnO powder has been synthesized by a Solvothermal method at low temperature with an aim to obtain nano crystalline ZnO and to study its ethanol and methanol gas sensing properties have been examined by nano crystalline Zinc oxide sensor in this study. The resulting powder was characterized by FT-IR and Powder X-ray diffraction (XRD) techniques which reveals the structure without any significant change in the cell parameters and the synthesized ZnO having average crystallite size of 10-25 nm, respectively. The gas sensor was made on alumina substrate. Various preparation parameters are optimized for maximum sensitivity. The sensitivity for different volatile organic gases such as ethanol and methanol was investigated at different temperatures and concentrations. The sensors fabricated from the nano sized powder exhibited higher ethanol sensing properties at a working temperature of 300° C and similar characteristics were observed for methanol also. ZnO based gas sensor exhibits high sensitivity for ethanol and methanol. Results demonstrated that the ZnO were promising for gas sensor with best sensing characteristics.

Pasha, Sk. Khadeer; Chidambaram, K.

2009-06-01

216

Cost effective passive sampling device for volatile organic compounds monitoring  

NASA Astrophysics Data System (ADS)

A laboratory-built passive sampler was developed as a simple and cost effective device for monitoring volatile organic compounds (VOCs) such as benzene, toluene and xylene (BTX). Common glass bottles (screw cap, 10 ml, 67.6×10.6 mm ID), packed with 75 mg of activated Tenax TA, were used as passive samplers. After exposed to real sample, the adsorbent was desorbed using a laboratory-built thermal desorption device. The analytes were purged to fill a sampling loop and then injected by a gas sampling valve to a gas chromatograph with a flame ionization detector (FID). All parameters, i.e. , desorption time, purge flow rate, gas chromatograph conditions were optimized to obtain high sensitivity, resolution and short analysis time. The system was calibrated by BTX standard gas and the linear regression coefficient of greater than 0.99 was obtained with detection limits 0.3, 0.2 and 0.7 ?g m -3 for benzene, toluene and xylene, respectively. The proposed method was implemented for the monitoring of BTX at 10 gasoline stations in Hat Yai, Thailand. The concentrations were found in the range of N.D.-19, 12-200 and 23-200 ?g m -3 for benzene, toluene and xylene, respectively.

Thammakhet, Chongdee; Muneesawang, Vilailuk; Thavarungkul, Panote; Kanatharana, Proespichaya

217

Modeling Emissions of Volatile Organic Compounds from New Carpets  

SciTech Connect

A simple model is proposed to account for observed emissions of volatile organic compounds (VOCs) from new carpets. The model assumes that the VOCs originate predominantly in a uniform slab of polymer backing material. Parameters for the model (the initial concentration of a VOC in the polymer, a diffusion coefficient and an equilibrium polymer/air partition coefficient) are obtained from experimental data produced by a previous chamber study. The diffusion coefficients generally decrease as the molecular weight of the VOCs increase, while the polymer/air partition coefficients generally increase as the vapor pressure of the compounds decrease. In addition, for two of the study carpets that have a styrene-butadiene rubber (SBR) backing, the diffusion and partition coefficients are similar to independently reported values for SBR. The results suggest that predictions of VOCs emissions from new carpets may be possible based solely on a knowledge of the physical properties of the relevant compounds and the carpet backing material. However, a more rigorous validation of the model is desirable.

Little, J.C.; Hodgson, A.T.; Gadgil, A.J.

1993-02-01

218

Resonance Raman spectroscopy of volatile organics -- Carbon tetrachloride  

SciTech Connect

Volatile organic chemicals are a class of pollutants which are regulated at very low levels by the EPA. Consequently a need exists as a part of site remediation efforts within DOE to develop technologies which will allow for the in situ monitoring of these chemicals. Resonance Raman spectroscopy is a potential technique to accomplish this if the resonance enhancement is sufficiently high. Carbon tetrachloride was selected as a test case. Measurements under resonance conditions at 248 nm showed an enhancement factor of 2 {times} 10{sup 4}. Using this value an estimate of the sensitivity for both in situ and remote monitoring of CCl{sup 4} was made. It was concluded that resonance Raman could be used to detect these chemicals at levels of regulatory interest. Future effort directed towards the development of a suitable probe as well as a field-portable system would be desirable. Such effort could be directed towards the solution of a particular monitoring problem within a DOE waste remediation project. Once developed, however, it should be easily generalized to the analysis of other VOC`s in other environments.

Barletta, R.E.; Veligdan, J.T. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

1994-09-01

219

Removing the smoking confounder from blood volatile organic compounds measurements.  

PubMed

Because smoking is a major contributor to the internal dose levels of many volatile organic compounds (VOCs), it is difficult to assess other VOC exposures among smokers. Purge and trap/gas chromatography/isotope-dilution mass spectrometry was used to determine the internal dose of VOCs of smokers and nonsmokers. Median whole blood concentrations of benzene, styrene, and toluene were shown to be approximately two times higher among smokers than among nonsmokers. In addition, smoking elevated the blood levels of ethylbenzene, m-/p-xylene, and o-xylene when the log-transformed data were compared. Smoking also led to greatly increased levels of 2,5-dimethylfuran. These results indicate that blood levels of many VOCs are highly correlated with blood levels of 2,5-dimethylfuran and that this effect is primarily a result of smoking. The smoking confounder to blood levels of VOCs can be removed by including the concentration of blood 2,5-dimethylfuran concentration when evaluating results from a health and exposure evaluation. Determining the blood 2,5-dimethylfuran concentration appears to be an effective means of correcting the confounding influence of smoking and supplies a way of determining lower-level exposures that previously could not have been distinguished from the effects of smoking. PMID:8757237

Ashley, D L; Bonin, M A; Hamar, B; McGeehin, M A

1995-10-01

220

Identification and quantification of volatile organic compounds from a dairy  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) that contribute to odor and air quality problems have been identified from the Washington State University Knott Dairy Farm using gas chromatography-mass spectroscopy (GC-MS). Eighty-two VOCs were identified at a lactating cow open stall and 73 were detected from a slurry wastewater lagoon. These compounds included alcohols, aldehydes, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons, terpenes, other hydrocarbons, amines, other nitrogen containing compounds, and sulfur-containing compounds. The concentration of VOCs directly associated with cattle waste increased with ambient air temperature, with the highest concentrations present during the summer months. Concentrations of most detected compounds were below published odor detection thresholds. Emission rates of ethanol (1026±513 ?g cow -1 s -1) and dimethyl sulfide (DMS) (13.8±10.3 ?g cow -1 s -1) were measured from the lactating stall area using an atmospheric tracer method and concentrations were plotted using data over a 2-year period. Emission rates of acetone (3.03±0.85 ng cow -1 s -1), 2-butanone (145±35 ng cow -1 s -1), methyl isobutyl ketone (3.46±1.11 ng cow -1 s -1), 2-methyl-3-pentanone (25.1±8.0 ng cow -1 s -1), DMS (2.19±0.92 ng cow -1 s -1), and dimethyl disulfide (DMDS) (16.1±3.9 ng cow -1 s -1) were measured from the slurry waste lagoon using a laboratory emission chamber.

Filipy, Jenny; Rumburg, Brian; Mount, George; Westberg, Hal; Lamb, Brian

221

Constituents of volatile organic compounds of evaporating essential oil  

NASA Astrophysics Data System (ADS)

Essential oils containing aromatic compounds can affect air quality when used indoors. Five typical and popular essential oils—rose, lemon, rosemary, tea tree and lavender—were investigated in terms of composition, thermal characteristics, volatile organic compound (VOC) constituents, and emission factors. The activation energy was 6.3-8.6 kcal mol -1, the reaction order was in the range of 0.6-0.8, and the frequency factor was 0.01-0.24 min -1. Toluene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, n-undecane, p-diethylbenzene and m-diethylbenzene were the predominant VOCs of evaporating gas of essential oils at 40 °C. In addition, n-undecane, p-diethylbenzene, 1,2,4-trimethylbenzene, m-diethylbenzene, and 1,2,3-trimethylbenzene revealed high emission factors during the thermogravimetric (TG) analysis procedures. The sequence of the emission factors of 52 VOCs (137-173 mg g -1) was rose ? rosemary > tea tree ? lemon ? lavender. The VOC group fraction of the emission factor of aromatics was 62-78%, paraffins were 21-37% and olefins were less than 1.5% during the TG process. Some unhealthy VOCs such as benzene and toluene were measured at low temperature; they reveal the potential effect on indoor air quality and human health.

Chiu, Hua-Hsien; Chiang, Hsiu-Mei; Lo, Cho-Ching; Chen, Ching-Yen; Chiang, Hung-Lung

2009-12-01

222

Advanced heat pump for the recovery of volatile organic compounds  

NASA Astrophysics Data System (ADS)

Emissions of Volatile Organic Compounds (VOC) from stationary industrial and commercial sources represent a substantial portion of the total U.S. VOC emissions. The 'Toxic-Release Inventory' of the U.S. Environmental Protection Agency estimates this to be at about 3 billion pounds per year (1987 estimates). The majority of these VOC emissions are from coating processes, cleaning processes, polymer production, fuel production and distribution, foam blowing, refrigerant production, and wood products production. The U.S. Department of Energy's (DOE) interest in the recovery of VOC stems from the energy embodied in the recovered solvents and the energy required to dispose of them in an environmentally acceptable manner. This Phase 1 report documents 3M's work in close working relationship with its subcontractor Nuclear Consulting Services (Nucon) for the preliminary conceptual design of an advanced Brayton cycle heat pump for the recovery of VOC. The Nucon designed Brayton cycle heat pump for the recovery of methyl ethyl ketone and toluene from coating operations at 3M Weatherford, OK, was used as a base line for the work under cooperative agreement between 3M and ODE. See appendix A and reference (4) by Kovach of Nucon. This cooperative agreement report evaluates and compares an advanced Brayton cycle heat pump for solvent recovery with other competing technologies for solvent recovery and reuse. This advanced Brayton cycle heat pump is simple (very few components), highly reliable (off the shelf components), energy efficient, and economically priced.

1992-03-01

223

Chemically-Resolved Volatility Measurements of Organic Aerosol from Different Sources  

NASA Astrophysics Data System (ADS)

A newly modified fast temperature-stepping thermodenuder (TD) was coupled to a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) for rapid quantification of chemically-resolved volatility of organic aerosols (OA) emitted from individual sources. The TD-AMS system was used to characterize primary OA (POA) from biomass burning, trash burning surrogates (paper and plastic), and meat cooking as well as chamber-generated secondary OA (SOA) from a-pinene and gasoline vapor. Almost all atmospheric models represent POA as non-volatile, with no allowance for evaporation upon heating or dilution, or condensation upon cooling. Our results indicate that all OAs observed show semi-volatile behavior and that most POAs are at least as volatile as SOA measured in urban environments. Biomass-burning OA (BBOA) exhibited a wide range of volatilities, but more often showed volatility similar to urban OA. Paper-burning resembles BBOA because of its high volatility and intermediate atomic oxygen-to-carbon (O/C) ratio, while meat-cooking OAs (MCOA) have consistently lower volatility than ambient OA. Chamber-generated SOA was significantly more volatile than urban SOA, challenging extrapolation of traditional laboratory volatility measurements to the atmosphere. Most OAs sampled show increasing O/C ratio and decreasing H/C (hydrogen-to-carbon) ratio with temperature, further indicating that more oxygenated OA components are less volatile.

Huffman, J. A.; Docherty, K. S.; Mohr, C.; Ulbrich, I. M.; Ziemann, P. J.; Onasch, T. B.; Jimenez, J. L.

2009-04-01

224

Volatile organic compounds in ambient air of Mumbai—India  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) are a major group of air pollutants which play a critical role in atmospheric chemistry. These contribute to toxic oxidants which are harmful to ecosystem, human health and atmosphere. The variability of pollutants is an important factor in determining human exposure to these chemicals. Data on levels of VOCs in developing countries, including India, are lacking. The present work deals with the estimation of target VOCs at 15 locations of five categories in Mumbai. The categories are residential, industrial, commercial, traffic intersections and petrol refueling stations. The monitoring was carried out during peak hours in the morning and evening, once every month, during May 2001 to April 2002. The study focused on target VOCs as defined by USEPA. Concentrations of benzene, at all the locations, were found to be much above the guidelines values prescribed by World Health Organization (WHO) for ambient air quality. All other VOCs were observed to be below the WHO guideline values. The results show that levels of VOCs in Mumbai were high. There is need for a regular monitoring schedule of VOCs in the urban environment. Variability studies are important to assess the exposure potential of pollutants which are an important parameter for health impact studies. This study also presents the variability of VOCs in the urban area of Mumbai. Variability was divided into measurement spatial, temporal and temporal-spatial interaction components. The temporal component along with temporal-spatial interaction component were the major contributors to variability. VOCs associated with mobile source emissions and emissions from marine source were found to be distributed uniformly in the urban atmosphere in Mumbai. the need for continuous monitoring, to capture short term peak concentrations and averages, is evident.

Srivastava, Anjali; Joseph, A. E.; Devotta, S.

225

Source apportionment modeling of volatile organic compounds in streams  

USGS Publications Warehouse

It often is of interest to understand the relative importance of the different sources contributing to the concentration cw of a contaminant in a stream; the portions related to sources 1, 2, 3, etc. are denoted cw,1, cw,2, cw,3, etc. Like c w, 'he fractions ??1, = cw,1/c w, ??2 = cw,2/cw, ??3 = cw,3/cw, etc. depend on location and time. Volatile organic compounds (VOCs) can undergo absorption from the atmosphere into stream water or loss from stream water to the atmosphere, causing complexities affecting the source apportionment (SA) of VOCs in streams. Two SA rules are elaborated. Rule 1: VOC entering a stream across the air/water interface exclusively is assigned to the atmospheric portion of cw. Rule 2: VOC loss by volatilization, flow loss to groundwater, in-stream degradation, etc. is distributed over cw,1 cw,2, c w,3, etc. in proportion to their corresponding ?? values. How the two SA rules are applied, as well as the nature of the SA output for a given case, will depend on whether transport across the air/water interface is handled using the net flux F convention or using the individual fluxes J convention. Four hypothetical stream cases involving acetone, methyl-tert-butyl ether (MTBE), benzene, chloroform, and perchloroethylene (PCE) are considered. Acetone and MTBE are sufficiently water soluble from air for a domestic atmospheric source to be capable of yielding cw values approaching the common water quality guideline range of 1 to 10 ??g/L. For most other VOCs, such levels cause net outgassing (F > 0). When F > 0 in a given section of stream, in the net flux convention, all of the ??j, for the compound remain unchanged over that section while cw decreases. A characteristic time ??d can be calculated to predict when there will be differences between SA results obtained by the net flux convention versus the individual fluxes convention. Source apportionment modeling provides the framework necessary for comparing different strategies for mitigating contamination at points of interest along a stream. ?? 2006 SETAC.

Pankow, J. F.; Asher, W. E.; Zogorski, J. S.

2006-01-01

226

Source apportionment of volatile organic compounds measured in Edmonton, Alberta  

NASA Astrophysics Data System (ADS)

From 2003 to 2009, whole air samples were collected at two sites in Edmonton and analyzed for over 77 volatile organic compounds (VOCs). VOCs were sampled in the downtown area (Central site) and an industrial area on the eastern side of the city (East site). Concentrations of most VOCs were highest at the East site, with an average total VOC mass concentration of 221 ?g m-3. The average total VOC mass concentration at the Central site was 65 ?g m-3. The United States Environmental Protection Agency's positive matrix factorization receptor model (EPA PMF) was used to apportion ambient concentrations of VOCs into eleven factors, which were associated with emissions sources. On average, 94 and 99% of the measured mass were apportioned by PMF at the East and Central site, respectively. Factors include transportation combustion (gasoline and diesel), industrial sources (industrial evaporative, industrial feedstock, gasoline production/storage, industrial chemical use), mixed mobile and industrial (gasoline evaporative, fugitive butane), a biogenic source, a natural gas related source, and a factor that was associated with global background pollutants transported into the area. Transportation sources accounted for more than half of the reconstructed VOC mass concentration at the Central site, but less than 10% of the reconstructed mass concentration at the East site. By contrast, industrial sources accounted for ten times more of the reconstructed VOC mass concentration at the East site than at the Central site and were responsible for approximately 75% of the reconstructed VOC mass concentration observed at the East site. Of the six industrial factors identified at the East site, four were linked to petrochemical industry production and storage. The two largest contributors to the reconstructed VOC mass concentration at the East site were associated with fugitive emissions of volatile species (butanes, pentanes, hexane, and cyclohexane); together, these two factors accounted for more than 50% of the reconstructed VOC mass concentration at the East site in contrast to less than 2% of the reconstructed mass concentration at the Central site. Natural gas related emissions accounted for 10%-20% of the reconstructed mass concentration at both sites. Biogenic emissions and VOCs associated with well-mixed global background were less than 10% of the reconstructed VOC mass concentration at the Central site and less than 3% of the reconstructed mass concentration at the East site.

McCarthy, Michael C.; Aklilu, Yayne-Abeba; Brown, Steven G.; Lyder, David A.

2013-12-01

227

Inorganic salts interact with oxalic acid in submicron particles to form material with low hygroscopicity and volatility  

NASA Astrophysics Data System (ADS)

Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. While the hygroscopicities of pure salts, di-carboxylic acids (DCA), and DCA salts are known, the hygroscopicity of internal mixtures of these components, as they are typically found in the atmosphere, has not been fully characterized. Here we show that inorganic-organic component interactions typically not considered in atmospheric models can lead to very strongly bound metal-organic complexes and greatly affect aerosol volatility and hygroscopicity; in particular, the bi-dentate binding of DCA to soluble inorganic ions. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the cloud condensation nuclei (CCN) activation diameter for particles with di-valent salts (e.g., CaCl2) and relatively small particle volume fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O : C ratios are capable of forming low-volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low-particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles without the need for a phase transition.

Drozd, G.; Woo, J.; Häkkinen, S. A. K.; Nenes, A.; McNeill, V. F.

2014-05-01

228

Organic acids as indicators of VOC oxidation: Measurements of formic acid and other gas-phase acids during SOAS  

NASA Astrophysics Data System (ADS)

Oxidation of volatile organic compounds (VOCs) in the atmosphere affects not only the oxidative capacity of the atmosphere, but also the formation of secondary organic aerosol. Organic acids are produced during VOC oxidation, although additional sources include biomass burning and primary emissions. While some organic acids are semi-volatile and dominantly present in the aerosol phase, formic acid and other small organic acids are dominantly present in the gas phase. The concentrations of these gas-phase organic acids can provide insight into oxidation chemistry. Here, we present measurements made during the Southern Oxidant and Aerosol Study (SOAS) in Centerville, Alabama during the summer of 2013 by a high resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) operated in a novel switching reagent ion mode to measure gas phase organic acids with both acetate (CH3COO-) and iodide (I-) reagent ions. Formic acid was quantified using for both ionization schemes using multiple calibration techniques. In this study, we will focus on the impact of anthropogenic pollutants, including nitrogen and sulfur oxides, on oxidation chemistry, and discuss the potential use of organic acids as tracers for atmospheric oxidation chemistry.

Farmer, D.; Brophy, P.; Murschell, T.

2013-12-01

229

High throughput volatile fatty acid skin metabolite profiling by thermal desorption secondary electrospray ionisation mass spectrometry.  

PubMed

The non-invasive nature of volatile organic compound (VOC) sampling from skin makes this a priority in the development of new screening and diagnostic assays. Evaluation of recent literature highlights the tension between the analytical utility of ambient ionisation approaches for skin profiling and the practicality of undertaking larger campaigns (higher statistical power), or undertaking research in remote locations. This study describes how VOC may be sampled from skin and recovered from a polydimethylsilicone sampling coupon and analysed by thermal desorption (TD) interfaced to secondary electrospray ionisation (SESI) time-of-flight mass spectrometry (MS) for the high throughput screening of volatile fatty acids (VFAs) from human skin. Analysis times were reduced by 79% compared to gas chromatography-mass spectrometry methods (GC-MS) and limits of detection in the range 300 to 900 pg cm(-2) for VFA skin concentrations were obtained. Using body odour as a surrogate model for clinical testing 10 Filipino participants, 5 high and 5 low odour, were sampled in Manilla and the samples returned to the UK and screened by TD-SESI-MS and TD-GC-MS for malodour precursors with greater than >95% agreement between the two analytical techniques. Eight additional VFAs were also identified by both techniques with chains 4 to 15 carbons long being observed. TD-SESI-MS appears to have significant potential for the high throughput targeted screening of volatile biomarkers in human skin. PMID:24992564

Martin, Helen J; Reynolds, James C; Riazanskaia, Svetlana; Thomas, C L Paul

2014-07-28

230

[Volatile oil of Anethum Graveolens L. as an inhibitor of yeast and lactic acid bacteria].  

PubMed

The antimicrobial activity of 25 volatile oils from aerial parts and seeds of dill (Anethum graveolens L.) of different geographical origin towards yeast Saccharomyces vini and lactic acid bacteria Lactobacterium buchneri was measured by serial dilutions. Volatile oils from mature seeds and green parts of the plants harvested at late vegetation phases showed the highest activity. The geographical origin of plants influenced insignificantly the antimicrobial activity of volatile oil. PMID:1208405

Shcherbanovsky, L R; Kapelev, I G

1975-01-01

231

VAPORIZATION TECHNIQUE TO MEASURE MUTAGENIC ACTIVITY OF VOLATILE ORGANIC CHEMICALS IN THE AMES/'SALOMELLA' ASSAY  

EPA Science Inventory

The purpose of the research was to develop and characterize a sensitive test method to detect mutagenic activity of volatile liquid organic chemicals (i.e., volatiles) in the Ames/Salmonella assay. A Tedlar bag vaporization technique was developed which increased contact time bet...

232

Transport and fate of volatile organic chemicals in unsaturated, nonisothermal, salty porous media  

Microsoft Academic Search

A wide variety of volatile organic chemicals (VOC) have been applied to agricultural land or buried in chemical waste sites. The fate of these chemicals depends upon several mechanisms such as sorption, degradation, and transport in liquid and gaseous phases. Understanding the transport mechanisms affecting the volatile chemicals can lead to better management strategies. A theory describing inorganic solute transport,

I. N Nassar; Robert Horton

1999-01-01

233

Concentration and biotoxicity assay of dilute aqueous solutions of volatile chlorinated organics using supercritical fluid extraction  

Microsoft Academic Search

Chlorinated volatile organic compounds (VOCs) were extracted from dilute aqueous samples into methanol to provide sufficient concentration for bacterial toxicity measurements. Using equipment designed to prevent loss of volatiles, standards and biological reactor effluents were filtered, adsorbed onto XAD?2 resin, extracted using supercritical carbon dioxide, and cryotrapped in liquid nitrogen with methanol as a keeper solvent for toxicity measurements using

Jerry E. Ongerth; Ryan Wacker; Stuart E. Strand; F. B. DeWalle

1995-01-01

234

A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.  

PubMed

There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models. PMID:12175024

Allaire, S E; Yates, S R; Ernst, F F; Gan, J

2002-01-01

235

Characterization of the non-volatile organic compounds in the aerosols of Hong Kong— identification, abundance and origin  

Microsoft Academic Search

The non-volatile solvent-extractable organic compounds (lipids) of biogenic and anthropogenic origins were isolated from total suspended particulates (TSP) samples collected during the winter months of 1993 in Hong Kong. They were characterized and quantified according to the following classes: n-alkanes, polycychc aromatic hydrocarbons, n-alkanoic acids, n-alkanols, and biomarkers such as triterpanes. Flash column chromatography technique was used to effectively separate

M. Zheng; T. S. M. Wan; M. Fang; F. Wang

1997-01-01

236

Adsorption of volatile organic compounds onto activated carbon cloths derived from a novel regenerated cellulosic precursor.  

PubMed

Activated carbon cloths (ACC) were prepared from lyocell, a novel regenerated cellulose nanofibre fabric, by phosphoric acid activation in inert atmosphere at two different final thermal treatment temperatures (864 and 963 degrees C). Benzene, toluene and n-hexane isotherms at 298 and 273K were measured in order to gain insight into the porous structure of the ACC and to evaluate their performance for the removal of volatile organic compounds (VOCs). The Dubinin-Radushkevich equation was employed to evaluate textural parameters of the ACC. The textural characteristics of the ACC were compared with those previously determined from nitrogen (77K) and carbon dioxide (273K) adsorption data. The samples were essentially microporous. The textural parameters calculated from the hydrocarbon isotherms were in good agreement with those evaluated from nitrogen isotherms for the ACC with the wider microporosity. Additionally, the Freundlich model provided a good description of the experimental isotherms for the three volatile organic compounds. The ACC obtained at the higher temperature exhibited a larger adsorption capacity. The ACC were also electrically conductive and showed potential for regeneration by the Joule effect, as determined from macroscopic electrical measurements before and after n-hexane adsorption. PMID:20042290

Ramos, M E; Bonelli, P R; Cukierman, A L; Ribeiro Carrott, M M L; Carrott, P J M

2010-05-15

237

Formaldehyde and other volatile organic chemical emissions in four FEMA temporary housing units.  

PubMed

Indoor concentrations of 33 volatile organic chemicals were measured in four unoccupied temporary housing units (THUs) belonging to the U.S. Federal Emergency Management Administration (FEMA). The highest level contaminants in the THUs include formaldehyde, acetic acid, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) with median concentrations of 440, 425, and 36 ppb, respectively. A number of volatile organic compounds (VOCs) were higher than published concentrations in other dwellings, but whole THU emission factors for most chemicals were either lower than or similar to values reported for newly constructed homes. However, several chemicals exceeded previously measured new building emission rates by over a factor of 5. Materials were collected from the THUs, and emission factors were determined using small chambers to identify the potential source of indoor contaminants. The individual materials were grouped by material type, and emissions were used to derive exposure concentrations for comparison to reference values. Using material loading factors and ventilation rates that are relevant to the trailers, all of the material types we tested had at least two chemicals (formaldehyde and nonanal) with derived concentrations in excess of chronic reference exposure levels or odor thresholds. The extensive use of composite wood products, sealants, and vinyl coverings, combined with the low air exchange rates relative to material surface areas, may explain the high concentrations of some VOCs and formaldehyde. PMID:19731654

Maddalena, Randy; Russell, Marion; Sullivan, Douglas P; Apte, Michael G

2009-08-01

238

Contribution of organic acids to the acidity of Finnish lakes.  

National Technical Information Service (NTIS)

This study provides a comprehensive assessment of the contribution of organic carbon and organic acids to the acid-base status of Finnish lakes, summarizing empirical organic acidity measurements (from 16 lakes) combined with the Finnish Lake Survey data ...

P. Kortelainen

1993-01-01

239

Global observations of oxygenated Volatile Organic Compounds from space  

NASA Astrophysics Data System (ADS)

Formaldehyde (HCHO), the smallest aldehyde of the atmosphere and glyoxal (CHO.CHO), the smallest a- dicarbonyl compound, are key intermediate products of the oxidation of volatile organic compounds (VOCs). Due to their short lifetime they are expected to provide valuable information on the global identification of the photochemical hot spots which are attributed to the various emission sources of anthropogenic, biogenic and biomass burning origin. This study presents the global composite maps of both HCHO and CHO.CHO vertical column densities as obtained, for the first time, from 2 different sensors the SCIAMACHY and the GOME-2 on board of the ENVISAT and METOP satellites, respectively. HCHO slant column densities (SCDs) were retrieved in the UV spectral region and the CHO.CHO in the VIS by applying the differential optical absorption spectroscopy technique (DOAS). Finally, the vertical column densities (VCDs) were calculated after taking into account the air mass factors computed with the radiative transfer model, SCIATRAN. These data sets of the VCDHCHO and VCDCHOCHO, covering the extended time period of 01.01.03 - 31.08.08, have been used to study the global seasonal and multi-annual behavior of both species. It was found that the highest values of these oVOCs, depending on the season, are observed above regions where anthropogenic activities, biogenic processes and biomass burning take place. South America, Africa, India, Indonesia and Asia (mainly South-eastern China) are among the dominant regions where high annual mean values of VCDHCHO (>1.0.1016molec.cm-2) and VCDCHO.CHO (>5.0.1014molec.cm-2) are computed. At higher latitudes, moderate annual mean values of VCDHCHO and VCDCHO.CHO are discernible, for example above North America, Europe and Australia. Notably, high column amounts of CHO.CHO are also observed over the tropical oceans and close to upwelling areas.

Vrekoussis, M.; Wittrock, F.; Richter, A.; Burrows, J. P.

2008-12-01

240

Measuring concentrations of volatile organic compounds in vinyl flooring.  

PubMed

The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and, consequently, affect mass transfer characteristics. To measure solid-phase concentrations under conditions resembling those in which the material would be installed in an indoor environment, a new technique was developed for measuring VOC concentrations in vinyl flooring (VF) and similar materials. A 0.09-m2 section of new VF was punched randomly to produce -200 0.78-cm2 disks. The disks were milled to a powder at -140 degrees C to simultaneously homogenize the material and reduce the diffusion path length without loss of VOCs. VOCs were extracted from the VF particles at room temperature by fluidized-bed desorption (FBD) and by direct thermal desorption (DTD) at elevated temperatures. The VOCs in the extraction gas from FBD and DTD were collected on sorbent tubes and analyzed by gas chromatography/mass spectrometry (GC/MS). Seven VOCs emitted by VF were quantified. Concentration measurements by FBD ranged from 5.1 microg/g VF for n-hexadecane to 130 microg/g VF for phenol. Concentrations measured by DTD were higher than concentrations measured by FBD. Differences between FBD and DTD results may be explained using free-volume and dual-mobility sorption theory, but further research is necessary to more completely characterize the complex nature of a diffusant in a polymer matrix. PMID:11518293

Cox, S S; Little, J C; Hodgson, A T

2001-08-01

241

Biogenic contributions to atmospheric volatile organic compounds in Azusa, California  

NASA Astrophysics Data System (ADS)

An objective of the 1997 Southern California Ozone Study (SCOS97) was to provide an up-to-date assessment of the importance of biogenic emissions for tropospheric ozone production in the South Coast Air Basin. To this end, ambient air samples were collected during September 1997 at the Azusa air-monitoring station for subsequent measurement of their radiocarbon (14C) content of the atmospheric nonmethane volatile organic compound (VOC) fraction. The 14C/12C ratio is proportional to the fraction of a sample's carbon that is biogenic. The proportionality constant was determined from local samples of vegetation, gasoline, and ambient CO2 collected during the same period. The median fraction of biogenic VOC observed from 0600 to 0900 hours (LT) was 7% (n = 5) with a range of -8% to 24%, from 1300 to 1600 hours it was 27% (n = 4) with a range of 11% to 39%, and from 1700 to 2000 hours it was 34 +/- 7% for a single sample. On the basis of calculated 24-hour back trajectories the dominant source region for the air masses associated with periods of high biogenic VOC-C levels was a sector extending from the north to the east. Over all time and space that the samples represent, the median fraction of biogenic VOC was 18% (n = 10). Expressed as an atmospheric mixing ratio, the overall (median and 95% confidence interval) biogenic VOC-carbon contribution was 80 +/- 50 nmol mol-1 which may be representative of the natural VOC-C background for the Los Angeles air basin.

Klouda, George A.; Lewis, Charles W.; Stiles, David C.; Marolf, Julie L.; Ellenson, William D.; Lonneman, William A.

2002-04-01

242

Passive remediation of chlorinated volatile organic compounds using barometric pumping  

SciTech Connect

The purpose of the Savannah River Integrated Demonstration Program, sponsored by the Department of Energy, is to demonstrate new subsurface characterization, monitoring, and remediation technologies. The interbedded clay and sand layers at the Integrated Demonstration Site (IDS) are contaminated with chlorinated volatile organic compounds (CVOCs). Characterization studies show that the bulk of the contamination is located in the approximately 40 m thick vadose zone. The most successful strategy for removing contaminants of this type from this environment is vapor extraction alone or in combination with other methods such as air sparging or enhanced bioremediation. Preliminary work at the IDS has indicated that natural pressure differences between surface and subsurface air caused by surface barometric fluctuations can produce enough gas flow to make barometric pumping a viable method for subsurface remediation. Air flow and pressure were measured in wells that are across three stratigraphic intervals in the vadose zone` The subsurface pressures were correlated to surface pressure fluctuations but were damped and lagging in phase corresponding to depth and stratum permeability. Piezometer wells screened at lower elevations exhibited a greater phase lag and damping than wells screened at higher elevations where the pressure wave from barometric fluctuations passes through a smaller number of low permeable layers. The phase lag between surface and subsurface pressures results in significant fluxes through these wells. The resultant air flows through the subsurface impacts CVOC fate and transport. With the appropriate controls (e.g. solenoid valves) a naturally driven vapor extraction system can be implemented requiring negligible operating costs yet capable of a large CVOC removal rate (as much as 1--2 kg/day in each well at the IDS).

Rossabi, J.; Looney, B.B.; Dilek, C.A.E.; Riha, B.; Rohay, V.J.

1993-12-31

243

Peat fires and air quality: volatile organic compounds and particulates.  

PubMed

There are numerous localized peat deposits on the Swan Coastal Plain, an urban and rural bioregion otherwise dominated by wetland ecosystems in southwestern Australia. Hydrological change is significant in the bioregion: urban development encroaches on wetlands, groundwater extraction provides the city population with most of its water, and rainfall declines will not recharge aquifers in the future. The wetland processes which contribute to the formation of these peat deposits have therefore changed and are becoming vulnerable to fire events with residents increasingly exposed to peat smoke. There is an imperative to characterise this peat smoke to determine if exposures are harmful or toxic, and opportunities to do so in this setting arise due to the absence of bushfire smoke which has confounded other international studies. We have measured volatile organic compounds (VOCs) and particulate concentrations from an opportunistic assessment of two peat fires. SUMMA canister grab samples and a portable GCMS were used to determine the VOCs with high 1h benzene concentrations of 16 and 30 ppm v/v. PM10 and PM2.5 particulate data were collected using an Osiris continuous analyser with 24h concentrations recorded at varying time periods (within a 5 months timeframe) ranging from 1h maximums of between 23-37 microgm(-3) for PM10 and 50.5-106 microgm(-3) for PM2.5. While the 24h averages were generally below national air quality standards, elevated 1h concentrations were observed on numerous occasions and on most days. Given the proximity of residential development to many peat deposits, a drying climate and the increased risk of arson in peri-urban environments, the health impacts of exposure to peat smoke need to be determined and if necessary measures developed to prevent exposure (which would include maintaining wetland sediment integrity so as to reduce its vulnerability to fire). PMID:19394676

Blake, D; Hinwood, A L; Horwitz, P

2009-07-01

244

Transport of volatile organic compounds across the capillary fringe  

NASA Astrophysics Data System (ADS)

Physical experiments were conducted to investigate the transport of a dissolved volatile organic compound (trichloroethylene, TCE) from shallow groundwater to the unsaturated zone under a variety of conditions including changes in the soil moisture profile and water table position. Experimental data indicated that at moderate groundwater velocities (0.1 m/d), vertical mechanical dispersion was negligible and molecular diffusion was the dominant vertical transport mechanism. Under these conditions, TCE concentrations decreased nearly 3 orders of magnitude across the capillary fringe and soil gas concentrations remained low relative to those of underlying groundwater. Data collected during a water table drop showed a short-term increase in concentrations throughout most of the unsaturated zone, but these concentrations quickly declined and approached initial values after the water table was returned to its original level. In the deep part of the unsaturated zone, the water table drop resulted in a long-term decrease in concentrations, illustrating the effects of hysteresis in the soil moisture profile. A two-dimensional random walk advection-diffusion model was developed to simulate the experimental conditions, and numerical simulations agreed well with experimental data. A simpler, one-dimensional finite-difference diffusion-dispersion model was also developed. One-dimensional simulations based on molecular diffusion also agreed well with experimental data. Simulations which incorporated mechanical dispersion tended to overestimate flux across the capillary fringe. Good agreement between the one- and two-dimensional models suggested that a simple, one-dimensional approximation of vertical transport across the capillary fringe can be useful when conditions are appropriate.

McCarthy, Kathleen A.; Johnson, Richard L.

1993-06-01

245

Identification and Quantification of Volatile Organic Compounds at a Dairy  

NASA Astrophysics Data System (ADS)

Livestock operations in the United States are an escalating environmental concern. The increasing density of livestock within a farm results in an increased emission of odorous gases, which have gained considerable attention by the public in recent years (National Research Council (NRC), 2002). Odorous compounds such as ammonia (NH3), volatile organic compounds (VOC's), and hydrogen sulfide (H2S) were reported to have a major effect on the quality of life of local residents living near livestock facilities (NRC, 2002). There has been little data collected related to identification and quantification of gaseous compounds collected from open stall dairy operations in the United States. The research to be presented identifies and quantifies VOCs produced from a dairy operation that contribute to odor and other air quality problems. Many different VOCs were identified in the air downwind of an open lactating cow stall area and near a waste lagoon at the Washington State University dairy using Gas Chromatography Mass Spectroscopy (GC-MS) analysis techniques. Identified compounds were very diverse and included many alcohols, aldehydes, amines, aromatics, esters, ethers, a fixed gas, halogenated hydrocarbons, hydrocarbons, ketones, other nitrogen containing compounds, sulfur containing compounds, and terpenes. The VOCs directly associated with cattle waste were dependent on ambient temperature, with the highest emissions produced during the summer months. Low to moderate wind speeds were ideal for VOC collection. Concentrations of quantified compounds were mostly below odor detection thresholds found in the literature, however the combined odor magnitude of the large number of compounds detected was most likely above any minimum detection threshold.

Filipy, J.; Mount, G.; Westberg, H.; Rumburg, B.

2003-12-01

246

Pretreatment of macroalgae for volatile fatty acid production.  

PubMed

In this study, a novel method was proposed for the biological pretreatment of macroalgae (Laminaria japonica, Pachymeniopsis elliptica, and Enteromorpha crinita) for production of volatile fatty acid (VFA) by anaerobic fermentation. The amount of VFA produced from 40 g/L of L. japonica increased from 8.3 g/L (control) to 15.6 g/L when it was biologically pretreated with Vibrio harveyi. The biological treatment of L. japonica with Vibrio spp. was most effective likely due to the alginate lyase activity of Vibrio spp. However, a considerable effect was also observed after biological pretreatment of P. elliptica and E. crinita, which are red and green algae, respectively. Alkaline pretreatment of 40 g/L of L. japonica with 0.5 N NaOH resulted in an increase of VFA production to 12.2 g/L. These results indicate that VFA production from macroalgae can be significantly enhanced using the proposed biological pretreatments. PMID:23942360

Pham, Thi Nhan; Um, Youngsoon; Yoon, Hyon Hee

2013-10-01

247

Diurnal variations and vertical gradients of biogenic volatile and semi-volatile organic compounds at the Tomakomai larch forest station in Japan  

Microsoft Academic Search

Volatile and semi-volatile organic compounds (VOCs and SVOCs) in the atmosphere control oxidative capacity of the air and formation of organic aerosols. To investigate sources, variations and fluxes of VOCs and SVOCs in the forest atmosphere, samples were collected in a larch forest at different heights in Tomakomai, Japan, from 3 to 5 September 2003 and were analyzed for VOCs

TERUYO I EDA; YA SUYUKI K ITAMORI; M ICHIHIRO M OCHIDA; RYUICHI HIRA TA; TA KASHI H IRANO; KOU I NUKAI; YA SUMI F UJINUMA

2006-01-01

248

Magmatic MORB Volatiles, Seafloor Hydrothermal Systems and Abiotic Organic Synthesis  

NASA Astrophysics Data System (ADS)

A plausible model for the origin of the observed C-O-H volatiles observed in MORB glasses is that they were incorporated in primary melts of the upwelling mantle. Based on the observed ferric/ferrous ratios in MORB glass, it is probable that the MORB source mantle contained diamond or graphite, depending on pressure. If true, then during partial mantle melting the graphite/diamond would react with FeO1.5 in garnet/spinel and clinopyroxene to form CO2 which would dissolve in the melt as carbonate ion. Using equation of state models for CO2 activity and ferric/ferrous ratios in the magma it is possible to model the amount of carbonate dissolved in the basaltic magma as a function of the degree of melting (Holloway and O'Day, 2000). The results require that rising MORB magma will become saturated in CO2 at depths much greater than those proposed for MORB magma chambers. Conversely H2O values observed in MORB glasses are far below saturation. However as CO2 reaches saturation and exsolves from the melt the low fO2 imposed by the low ferric/ferrous ratio results in a high H2/H2O ratio in the exsolving supercritical fluid. We have shown that fluids with this composition produce methanol (CH3OH) in the presence of magnetite at seafloor hydrothermal P-T conditions in a flow-through system (Voglesonger, et al., 2001) and that aqueous methanol solutions react in montmorillonite clay interlayers to form a wide variety of complex hydrocarbon molecules, the most abundant being hexamethyl benzene (Williams, et al., 2005). Methyl stearate (C17H35COOCH3) was also observed in moderate amounts. Holloway, J. R. and P. A. O'Day (2000). "Production of CO2 and H2 by Diking-Eruptive Events at Mid-Ocean Ridges: Implications for Abiotic Organic Synthesis and Global Geochemical Cycling." International Geology Review 42: 673-683. Voglesonger, K. M., J. R. Holloway, E. E. Dunn, P. J. Dalla-Betta and P. A. O'Day (2001). "Experimental Abiotic Synthesis of Methanol in Seafloor Hydrothermal Systems." Chemical Geology 180: 129-139. Williams, L. B., B. C. Canfield, K. M. Voglesonger and J. R. Holloway (2005). "Organic molecules formed in a primordial womb." Geology 33: 913-916.

Holloway, J. R.

2007-12-01

249

Exchange of volatile organic compounds in the boreal forest floor  

NASA Astrophysics Data System (ADS)

Terrestrial ecosystems, mainly plants, emit large amounts of volatile organic compounds (VOCs) into the atmosphere. In addition to plants, VOCs also have less-known sources, such as soil. VOCs are a very diverse group of reactive compounds, including terpenoids, alcohols, aldehydes and ketones. Due to their high reactivity, VOCs take part in formation and growth of secondary organic aerosols in the atmosphere and thus affect also Earth's radiation balance (Kulmala et al. 2004). We have studied boreal soil and forest floor VOC fluxes with chamber and snow gradient techniques we were developed. Spatial and temporal variability in VOC fluxes was studied with year-round measurements in the field and the sources of boreal soil VOCs in the laboratory with fungal isolates. Determination of the compounds was performed mass spectrometrically. Our results reveal that VOCs from soil are mainly emitted by living roots, above- and belowground litter and microbes. The strongest source appears to be litter, in which both plant residuals and decomposers play a role in the emissions. Soil fungi showed high emissions of lighter VOCs, like acetone, acetaldehyde and methanol, from isolates. Temperature and moisture are the most critical physical factors driving VOC fluxes. Since the environment in boreal forests undergoes strong seasonal changes, the VOC flux strength of the forest floor varies markedly during the year, being highest in spring and autumn. The high spatial heterogeneity of the forest floor was also clearly visible in VOC fluxes. The fluxes of other trace gases (CO2, CH4 and N2O) from soil, which are also related to the soil biological activity and physical conditions, did not show correlations with the VOC fluxes. These results indicate that emissions of VOCs from the boreal forest floor account for as much as several tens of percent, depending on the season, of the total forest ecosystem VOC emissions. This emphasises that forest floor compartment should be taken into consideration when assessing ecosystem level VOC fluxes. These results can be utilized also in air chemistry models, which are almost entirely lacking the below-canopy compartment. Kulmala, M., Suni, T., Lehtinen, K.E.J., Dal Maso, M., Boy, M., Reissell, A., Rannik, Ü., Aalto, P., Keronen, P., Hakola, H., Bäck, J., Hoffmann, T., Vesala, T. & Hari, P. 2004. A new feedback mechanism linking forests, aerosols, and climate. Atmospheric Chemistry and Physics 4: 557-562.

Aaltonen, Hermanni; Bäck, Jaana; Pumpanen, Jukka; Pihlatie, Mari; Hakola, Hannele; Hellén, Heidi; Aalto, Juho; Heinonsalo, Jussi; Kajos, Maija K.; Kolari, Pasi; Taipale, Risto; Vesala, Timo

2013-04-01

250

Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) can react in the atmosphere to form organic nitrates, which serve as NOx (NO + NO2) reservoirs, impacting ozone and secondary organic aerosol production, the oxidative capacity of the atmosphere, and nitrogen availability to ecosystems. To examine the contributions of biogenic emissions and the formation and fate of organic nitrates in a forest environment, we simulated the oxidation of 57 individual BVOCs emitted from a rural mixed forest in Northern Michigan. Of the total simulated organic nitrates, monoterpenes contributed ~70% in the early morning at ~12 m above the forest canopy when isoprene emissions were low. In the afternoon, when vertical mixing and isoprene nitrate production were highest, the simulated contribution of isoprene-derived organic nitrates was greater than 90% at all altitudes, with the concentration of secondary isoprene nitrates increasing with altitude. Key BVOC-oxidant reactions were identified for future laboratory and field investigations into reaction rate constants, yields, and speciation of oxidation products. Forest succession, wherein aspen trees are being replaced by pine and maple trees, was predicted to lead to increased afternoon concentrations of monoterpene-derived organic nitrates. This further underscores the need to understand the formation and fate of these species, which have different chemical pathways and oxidation products compared to isoprene-derived organic nitrates and can lead to secondary organic aerosol formation.

Pratt, K. A.; Mielke, L. H.; Shepson, P. B.; Bryan, A. M.; Steiner, A. L.; Ortega, J.; Daly, R.; Helmig, D.; Vogel, C. S.; Griffith, S.; Dusanter, S.; Stevens, P. S.; Alaghmand, M.

2012-07-01

251

VOLATILE ORGANIC COMPOUNDS INHIBIT HUMAN AND RAT NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS EXPRESSED IN XENOPUS OOCYTES.  

EPA Science Inventory

This manuscript provides evidence to indicate that rats and humans are equally sensitive at the pharmacodynamic level to effects of volatile organic compounds. ? This manuscript also presents novel data that provides a plausible mechanism, disruption of ion channel functi...

252

PERTURBATION OF VOLTAGE-SENSITIVE Ca2+ CHANNEL FUNCTION BY VOLATILE ORGANIC SOLVENTS.  

EPA Science Inventory

The mechanisms underlying the acute neurophysiological and behavioral effects of volatile organic compounds (VOCs) remain to be elucidated. However, the function of neuronal ion channels is perturbed by VOCs. The present study examined effects of toluene (TOL), trichloroethylene ...

253

TREATMENT OF CHLORINATED VOLATILE ORGANIC COMPOUNDS IN UPFLOW WETLAND MESOCOSMS. (R828773C003)  

EPA Science Inventory

Sorption, biodegradation and hydraulic parameters were determined in the laboratory for two candidate soil substrate mixtures for construction of an upflow treatment wetland for volatile organic compounds (VOCs) at a Superfund site. The major parent contaminants in the groundw...

254

FIELD EVALUATION OF A SIMPLE MICROCOSM SIMULATING THE BEHAVIOR OF VOLATILE ORGANIC COMPOUNDS IN SUBSURFACE MATERIALS  

EPA Science Inventory

A simple batch microcosm had previously been developed to simulate the behavior of volatile organic compounds in unconsolidated subsurface material. The microcosm was evaluated by comparing the behavior of tetrachloroethylene, bromoform, carbon tetrachloride, 1,2-dichlorobenzene,...

255

Air cleaner Efficiencies for Removal of Nitrogen Dioxide and Volatile Organic Compounds.  

National Technical Information Service (NTIS)

The objective of this research was to measure the initial effective cleaning rate (ECR) of selected air cleaners for removing NO2 and six representative volatile organic compounds (VOC) from air. Four portable air cleaners, representing three different pr...

J. M. Daisey A. T. Hodgson

1988-01-01

256

BREAKPOINT CHLORINATION/ACTIVATED CARBON TREATMENT: EFFECT ON VOLATILE HALOGENATED ORGANICS  

EPA Science Inventory

The production and removal of six volatile halogenated organic compounds during treatment of tertiary clarified and filtered wastewater by breakpoint chlorination and activated carbon was examined in a continuous flow pilot plant. Short contact time breakpoint chlorination of fil...

257

COMPARISON OF PROCEDURES TO DETERMINE ADSORPTION CAPACITY OF VOLATILE ORGANIC COMPOUNDS ON ACTIVATED CARBON  

EPA Science Inventory

Numerous volatile organic compounds (VOCs) are under regulatory consideration for inclusion in the National Primary Drinking Water Standards. Adsorption is a cost-effective treatment technology for control of VOCs. Adsorption capacities were determined for fifteen VOCs in distill...

258

Feasibility Study of Preparing Performance Evaluation Soils for Analyzing Volatile Organic Compounds.  

National Technical Information Service (NTIS)

Vapor fortification, an alternative method for spiking soils with volatile organic compounds for quality assurance/quality control, was improved by minimizing the effects of numerous variables. The procedure developed resulted in average analytes concentr...

A. D. Hewitt

1993-01-01

259

EXPOSURE OF HUMANS TO A VOLATILE ORGANIC MIXTURE: I. BEHAVIORAL ASSESSMENT  

EPA Science Inventory

Subjective reactions of discomfort, impaired air quality, irritation of mucosal membranes, and impaired memory have been reported to chemically sensitive subjects during exposure to volatile organic compounds (VOC's) found in new buildings. 6 normal healthy male subjects aged 18-...

260

Control of Volatile Organic Emissions from Petroleum Liquid Storage in External Floating Roof Tanks.  

National Technical Information Service (NTIS)

This report provides the necessary guidance for development of regulations limiting emissions of volatile organic compounds (VOC) from storage of petroleum liquids in external floating roof tanks. Reasonably available control technology (RACT) is defined ...

R. K. Burr K. C. Brothers J. G. Wright

1978-01-01

261

SUPERCRITICAL FLUID EXTRACTION-GAS CHROMATOGRAPHY OF VOLATILE ORGANIC COMPOUNDS (VOC) FROM TENAX DEVICES  

EPA Science Inventory

The report describes the development and evaluation of on-line supercritical fluid extraction-gas chromatography instrumentation and methodology for the analysis of volatile organic compounds (VOC) from adsorbent sampling devices. Supercritical fluid extraction offers potential a...

262

RELATIONSHIPS BETWEEN LEVELS OF VOLATILE ORGANIC COMPOUNDS IN AIR AND BLOOD FROM THE GENERAL POPULATION  

EPA Science Inventory

Background: The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at ppb levels. Objectives: This study investigates relationships between ...

263

VOLATILE ORGANIC COMPOUNDS IN INDOOR AIR: A SURVEY OF VARIOUS STRUCTURES  

EPA Science Inventory

Co-workers collected indoor air samples in their homes in SUMMA polished canisters. Upon receipt in the laboratory, the whole air samples were analyzed for volatile organic compounds (VOCs) using cryogenic sample preconcentration and subsequent capillary column chromatography. Ea...

264

INTERLABORATORY STUDY OF A TEST METHOD FOR MEASURING TOTAL VOLATILE ORGANIC COMPOUND CONTENT OF CONSUMER PRODUCTS  

EPA Science Inventory

The report describes results of an interlaboratory study to estimate repeatability (precision of analyses performed by a single laboratory) and reproducibility (precision analyses performed by different laboratories) of a consumer products volatile organic compound (VOC) measurem...

265

AUTOMATED CRYOGENIC PRECONCENTRATION AND GAS CHROMATOGRAPHIC DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN AIR  

EPA Science Inventory

The performances of two nominally identical automated monitors for quantifying volatile organic compounds were compared on identical ambient laboratory air samples. The monitors incorporate cryogenic preconcentration subunits specially designed for controlled release of liquid ni...

266

NEUROTOXIC EFFECTS OF CONTROLLED EXPOSURE TO A COMPLEX MIXTURE OF VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

Subjective reactions of discomfort, impaired air quality, irritation of mucosal membranes, and impaired memory have been reported in chemically sensitive subjects during exposure to volatile organic compounds (VOC's) found in new buildings. 6 normal healthy male subjects aged 18-...

267

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 9. QUALITY ASSURANCE  

EPA Science Inventory

Radian Corporation, under contract to the U.S. Environmental Protection Agency, performed site selection, test plan development, and performance tests of catalytic incinerators used for volatile organic compound (VOC) emissions control at industrial sites. VOC emissions are of co...

268

HENRY'S LAW CONSTANTS AND MICELLAR PARTITIONING OF VOLATILE ORGANIC COMPOUNDS IN SURFACTANT SOLUTIONS  

EPA Science Inventory

Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor-liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace expe...

269

FACTORS CONTROLLING THE EMISSIONS OF MONOTERPENES AND OTHER VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

Plants contain a number of volatile organic compounds, including isoprene, mono- and sesquiterpenes, alcohols, aldehydes, ketones, and esters. ndividual plant species have unique combinations of these compounds; consequently, the emission pattern for each species is also specific...

270

Factors Controlling the Emissions of Monoterpenes and Other Volatile Organic Compounds.  

National Technical Information Service (NTIS)

Plants contain a number of volatile organic compounds, including isoprene, mono- and sesquiterpenes, alcohols, aldehydes, ketones, and esters. Individual plant species have unique combinations of these compounds; consequently, the emission pattern for eac...

D. T. Tingey D. P. Turner J. A. Weber

1990-01-01

271

Control of Volatile Organic Emissions from Existing Stationary Sources. Volume VIII: Graphic Arts - Rotogravure and Flexography.  

National Technical Information Service (NTIS)

This document provides guidance for development of regulations to limit emissions of volatile organic compounds from rotogravure and flexographic printing operations. This guidance includes recommended control requirements for carbon adsorption and incine...

E. J. Vincent W. M. Vatavuk

1978-01-01

272

SOIL SORPTION OF VOLATILE AND SEMIVOLATILE ORGANIC COMPOUNDS IN A MIXTURE  

EPA Science Inventory

Studies were conducted to evaluate lipophilicity as a predictor sorption for a mixture of organic compounds with high vapor pressures commonly present at hazardous waste sites. Sorption partition coefficients (Kp) for the mixture of 16 volatile and semivolatile ...

273

76 FR 41086 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound...  

Federal Register 2010, 2011, 2012, 2013

...Volatile Organic Compound Reinforced Plastic Composites Production Operations Rule...compound (VOC) emissions from reinforced plastic composites production operations. This...applies to any facility that has reinforced plastic composites production operations....

2011-07-13

274

IMPROVED METHOD FOR THE STORAGE OF GROUND WATER SAMPLES CONTAINING VOLATILE ORGANIC ANALYTES  

EPA Science Inventory

The sorption of volatile organic analytes from water samples by the Teflon septum surface used with standard glass 40-ml sample collection vials was investigated. Analytes tested included alkanes, isoalkanes, olefins, cycloalkanes, a cycloalkene, monoaromatics, a polynuclear arom...

275

Study on Determination and Composition of Volatile Organic Compounds of Larix Gmelini Particles  

Microsoft Academic Search

The static head space solid-phase micro-extraction (HS-SPME) technique was applied to extract the volatile organic compounds of Larix gmelini particles,and the extracting condition was optimized, that is, 40 minute extracting time at 80°C, then 30 minute absorption, 4 minute desorption. The volatile organic compounds (VOCs) of Larix gmelini particles were analyzed by head space solid-phase micro-extraction gas chromatography-mass spectroscopy (HS-SPME-GC-MS)

Shijing Sun; Jun Shen; Zhiming Liu

2010-01-01

276

Determination of volatile organic compounds and ETS apportionment in 49 homes  

Microsoft Academic Search

Forty-nine nonsmoking married women participated in a home personal exposure study for 28 volatile organic compounds (VOCs) and total volatile organic compounds (TVOCs). The women were selected and classified according to 18 socioeconomic categories based on age (18–34 y, 35–49 y, 50–64 y), family income ($40K), and husband's smoking status. Of the 29 analytes, 21 demonstrated no statistically significant difference

David L. Heavner; Walter T. Morgan; Michael W. Ogden

1995-01-01

277

Volatile and amino acid profiling of dry cured hams from different swine breeds and processing methods.  

PubMed

The flavor of dry cured ham explains the high appreciation of this product and it determines consumer acceptance. Volatile compounds provide valuable information about the odor and sensory quality of dry cured hams. Since amino acids are the origin of some volatile compounds of dry cured ham, the volatile and amino acid compositions of forty-one dry cured hams from Spain and France were determined to establish associations between them. The samples included different pig breeds (non Iberian vs. Iberian), which were additionally affected by different maturation times and feeding types (acorn vs. fodder). Results showed that 20 volatile compounds were able to distinguish Iberian and non Iberian hams, and 16 of those had relevant sensory impact according to their odor activity values. 3-Methylbutanol, 2-heptanol and hexanal were among the most concentrated volatile compounds. In the case of non-volatile compounds, the concentrations of amino acids were generally higher in Iberian hams, and all the amino acids were able to distinguish Iberian from non Iberian hams with the exception of tryptophan and asparagine. A strong correlation of some amino acids with volatile compounds was found in the particular case of alcohols and aldehydes when only Iberian hams were considered. The high correlation values found in some cases proved that proteolysis plays an important role in aroma generation. PMID:23552905

García-González, Diego L; Aparicio, Ramón; Aparicio-Ruiz, Ramón

2013-01-01

278

Semi-volatile secondary organic aerosol in urban atmospheres: meeting a measurement challenge  

NASA Astrophysics Data System (ADS)

Ammonium nitrate and semi-volatile organic compounds are significant components of fine particles in urban atmospheres. These components, however, are not properly determined with current US EPA accepted methods such as the PM 2.5 FRM or other single filter samplers due to significant losses of semi-volatile material (SVM) from particles collected on the filter during sampling. Continuous PM 2.5 mass measurements are attempted using methods such as the R&P TEOM monitor. This method, however, heats the sample to remove particle-bound water which also results in evaporation of SVM. Research at Brigham Young University has resulted in samplers for both the integrated and continuous measurement of total PM 2.5, including the SVM. The PC-BOSS is a charcoal diffusion denuder based sampler for the determination of fine particulate chemical composition including the semi-volatile organic material. The RAMS is a modified TEOM monitor which includes diffusion denuders and Nafion dryers to remove gas phase material which can be absorbed by a charcoal sorbent filter. The RAMS then uses a "sandwich filter" consisting of a conventional particle collecting Teflon coated TX40 filter, followed by an activated charcoal sorbent filter which retains any semi-volatile ammonium nitrate or organic material lost from the particles collected on the TEOM monitor Teflon coated filter, thus allowing for determination of total PM 2.5 mass including the SVM. Recent research conducted by Brigham Young University using these two samplers has indicated the following about semi-volatile organic aerosol: The majority of semi-volatile fine particulate organic material is secondary organic aerosol. This semi-volatile organic aerosol is not retained on the heated filter of a regular TEOM monitor and hence is not measured by this sampling technique. In addition, secondary ammonium nitrate is also lost. Much of the semi-volatile organic aerosol is also lost during sampling from single filter samplers such as the PM 2.5 FRM sampler. The amount of semi-volatile organic aerosol lost from single filter samplers can vary from less than 1/3 that lost from heated TEOM filters during cold winter conditions to essentially all during warm summer conditions. Semi-volatile organic aerosol can only be reliably collected using an appropriate denuder sampler. Either a PM 2.5 FRM sampler or the IMPROVE sampler can be easily modified to a denuder sampler with filters which can be analyzed for semi-volatile OC, nonvolatile OC and EC using existing OC/EC analytical techniques. The research upon which these statements are based is summarized in this document.

Eatough, Delbert J.; Long, Russell W.; Modey, William K.; Eatough, Norman L.

279

The role of secreting structures position on the leaf volatile organic compounds of Hypericum androsaemum.  

PubMed

Hypericum androsaemum L. presents typical translucent, essential oil producing glands, which are distributed on the leaf along both margins (margin glands) and on the lamina (lamina glands). The gland secretion was studied by histochemical and chemical analysis; the gland content was sampled directly from the secretory glands, and the volatile organic compounds (VOC) of the margin and lamina glands were separately analyzed. The lipophilic fraction of the lamina glands had as main components: (E)-2-hexenal (15.5%), hexadecanoic acid (14.7%), beta-caryophyllene (11.2%), germacrene B (11.0%) and gamma-himachalene (9.8%). The lipophilic fraction of the margin glands had as its main components: beta-pinene (22.0%), limonene (17.6%), (E)-beta-ocimene (6.1%), methyl linoleate (5.7%), terpinolene (5.4 %), (E)-2-hexenal (4.9%) and alpha-pinene (4.1%). PMID:20184033

Giuliani, Claudia; Pellegrino, Roberto Maria; Tirillini, Bruno; Maleci Bini, Laura

2010-01-01

280

Acid-Volatile Sulfide as a Factor Mediating Cadmium and Nickel Bioavailability in Contaminated Sediments.  

National Technical Information Service (NTIS)

The authors investigated the influence of sulfide, measured as acid-volatile sulfide (AVS), on the bioavailability of cadmium and nickel in sediments. Seventeen samples from an estuarine system heavily contaminated with cadmium and nickel were analyzed fo...

G. T. Ankley G. L. Phipps E. L. Leonard D. A. Benoit V. R. Mattson

1991-01-01

281

A Push-Pull Test to Measure Volatilization Fluxes of Organic Pollutants without Flux Chambers  

NASA Astrophysics Data System (ADS)

Volatilization of organic contaminants is a potentially significant removal mechanism from wetlands, but field measurements are scarce and the physiochemical controls on volatilization from wetland soils remain poorly understood. It has been established that volatilization rates of certain pollutants are enhanced by vegetation and are strongly correlated with evapotranspiration (ET). These observations rely on flux chambers measurements, which are characterized by significant uncertainty due the chamber's effects on the meteorological variables around the plant and consequent impact on the biophysical processes governing ET and plant uptake of soil contaminants. Here we present data from a mesocosm study using a modified single-well push-pull test to measure in-situ volatilization rates from inundated soils vegetated with the wetland macrophytes Scirpus acutus and Typha latifolia, as well as from unplanted soil. This new method uses a test solution containing the volatile tracers sulfur hexafluoride (SF6), helium (He), and dichlorodifluoromethane (CFC-12) to estimate first-order volatilization rates and examine the relationship between physiochemical properties and volatilization rates. The test also yields an estimate for the volume of subsurface gas bubbles, which is used to derive a retardation factor for the effect of interphase partitioning on the estimation of kinetic parameters. We evaluate models to partition observed fluxes into different pathways for plant-mediated volatilization: transpirational uptake and consequent volatilization, and gas-phase diffusion through porous root aerenchyma. Those models are then used to scale tracer-derived volatilization fluxes to priority organic pollutants including benzene, trichloroethylene, and vinyl chloride. We also discuss the implementation of this method at field scales to estimate volatilization as a component of phytoremediation applications.

Reid, M. C.; Jaffe, P. R.

2011-12-01

282

Volatile organic compound emission factors from roadside measurements  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) play a significant role in the generation of urban photochemical smog. In addition, some VOCs, such as benzene, are harmful to human health. In Japan, motor vehicles are the dominant source of VOCs. Therefore, it is important to determine the emission of VOCs from vehicles in order to estimate human risk and the production mechanisms of photochemical smog. In this study, we estimated emission factors with a methodology that considered the following points: (1) real-world emissions, (2) individual VOCs, (3) low vehicle speeds, (4) low investigation cost, and (5) user-friendly methodology. Samples were collected approximately 5 m from each side of National Route No. 467 in Kanagawa Prefecture, Japan. Sampling consisted of twelve 1-h sampling periods at three points on three dates: 21 February 2003 (7:00-19:00), 13 May 2003 (7:00-19:00), and 13 September 2003 (8:00-20:00). The samples were analyzed using GC/FID and GC/MS. In addition, information on vehicle types, traffic volumes, and weather conditions was collected from beside the road. Emission factors of individual VOCs were estimated from the measured data by running the CALINE4 dispersion model as an inverse model. The average speed of all vehicles was 22 km h -1; 81.3% of all vehicles were light-duty vehicles, 12.3% were heavy-duty vehicles, and 6.5% were motorcycles. We estimated the emission factors of 34 individual VOCs. The emission factors for all vehicles combined averaged over all sampling days ranged from 0.25 to 51 mg vehicle -1 km -1. The emission factors of benzene and toluene were 5.2 and 17 mg vehicle -1 km -1, respectively. In addition, the estimated emission factors were compared with those estimated from other recent studies. The emission factors for light-duty vehicles (LDVs), heavy-duty vehicles (HDVs), and motorcycles separately were also estimated by using a non-negative least squares method. However, these emission factors were found to be unreliable for the current sample size; therefore, the sample size needed to estimate reliable emission factors was calculated.

Kawashima, Hiroto; Minami, Shigeki; Hanai, Yoshimichi; Fushimi, Akihiro

283

Volatile Organic Compound Investigation Results, 300 Area, Hanford Site, Washington  

SciTech Connect

Unexpectedly high concentrations of volatile organic compounds (VOC) were discovered while drilling in the unconfined aquifer beneath the Hanford Site’s 300 Area during 2006. The discovery involved an interval of relatively finer-grained sediment within the unconfined aquifer, an interval that is not sampled by routine groundwater monitoring. Although VOC contamination in the unconfined aquifer has been identified and monitored, the concentrations of newly discovered contamination are much higher than encountered previously, with some new results significantly higher than the drinking water standards. The primary contaminant is trichloroethene, with lesser amounts of tetrachloroethene. Both chemicals were used extensively as degreasing agents during the fuels fabrication process. A biological degradation product of these chemicals, 1,2-dichloroethene, was also detected. To further define the nature and extent of this contamination, additional characterization drilling was undertaken during 2007. Four locations were drilled to supplement the information obtained at four locations drilled during the earlier investigation in 2006. The results of the combined drilling indicate that the newly discovered contamination is limited to a relatively finer-grained interval of Ringold Formation sediment within the unconfined aquifer. The extent of this contamination appears to be the area immediately east and south of the former South Process Pond. Samples collected from the finer-grained sediment at locations along the shoreline confirm the presence of the contamination near the groundwater/river interface. Contamination was not detected in river water that flows over the area where the river channel potentially incises the finer-grained interval of aquifer sediment. The source for this contamination is not readily apparent. A search of historical documents and the Hanford Waste Information Data System did not provide definitive clues as to waste disposal operations and/or spills that might have resulted in groundwater contamination in this sediment, although several relatively small accidental releases of VOCs have occurred in the past in the northern portion of the 300 Area. It is likely that large quantities of degreasing solutions were disposed to the North and South Process Ponds during the 1950s and 1960s, and that evidence for them in the upper portion of the unconfined aquifer has been removed because of groundwater movement through the much more transmissive sediment. Also, investigations to date have revealed no evidence to suggest that a dense, non-aqueous phase liquid remains undetected in the subsurface. Potential pathways for contamination to migrate from this finer-grained sediment include groundwater movement through the interval to offshore locations in the Columbia River channel, dispersion out of the finer-grained interval into the overlying transmissive sediment (again, with transport to the riverbed), and potential future withdrawal via water supply wells.

Peterson, Robert E.; Williams, Bruce A.; Smith, Ronald M.

2008-07-07

284

Dynamics of the anaerobic process: effects of volatile fatty acids.  

PubMed

A complex and fast dynamic response of the anaerobic biogas system was observed when the system was subjected to pulses of volatile fatty acids (VFAs). It was shown that a pulse of specific VFAs into a well-functioning continuous stirred tank reactor (CSTR) system operating on cow manure affected both CH(4) yield, pH, and gas production and that a unique reaction pattern was seen for the higher VFAs as a result of these pulses. In this study, two thermophilic laboratory reactors were equipped with a novel VFA-sensor for monitoring specific VFAs online. Pulses of VFAs were shown to have a positive effect on process yield and the levels of all VFA were shown to stabilize at a lower level after the biomass had been subjected to several pulses. The response to pulses of propionate or acetate was different from the response to butyrate, iso-butyrate, valerate, or iso-valerate. High concentrations of propionate affected the degradation of all VFAs, while a pulse of acetate affected primarily the degradation of iso-valerate or 2-methylbutyrate. Pulses of n-butyrate, iso-butyrate, and iso-valerate yielded only acetate, while degradation of n-valerate gave both propionate and acetate. Product sensitivity or inhibition was shown for the degradation of all VFAs tested. Based on the results, it was concluded that measurements of all specific VFAs are important for control purposes and increase and decrease in a specific VFA should always be evaluated in close relationship to the conversion of other VFAs and the history of the reactor process. It should be pointed out that the observed dynamics of VFA responses were based on hourly measurements, meaning that the response duration was much lower than the hydraulic retention time, which exceeds several days in anaerobic CSTR systems. PMID:12701145

Pind, Peter F; Angelidaki, Irini; Ahring, Birgitte K

2003-06-30

285

Organic non-volatile memories from ferroelectric phase separated blends  

NASA Astrophysics Data System (ADS)

Ferroelectric polarisation is an attractive physical property for non-volatile binary switching. The functionality of the targeted memory should be based on resistive switching. Conductivity and ferroelectricity however cannot be tuned independently. The challenge is to develop a storage medium in which the favourable properties of ferroelectrics such as bistability and non-volatility can be combined with the beneficial properties provided by semiconductors such as conductivity and rectification. In this contribution we present an integrated solution by blending semiconducting and ferroelectric polymers into phase separated networks. The polarisation field of the ferroelectric modulates the injection barrier at the semiconductor--metal contact. This combination allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read-out non-destructively. Based on this general concept a non-volatile, reversible switchable Schottky diode with relatively fast programming time of shorter than 100 microseconds, long information retention time of longer than 10^ days, and high programming cycle endurance with non-destructive read-out is demonstrated.

Asadi, Kamal; de Leeuw, Dago; de Boer, Bert; Blom, Paul

2009-03-01

286

DETERMINATION OF VOLATILE ORGANICS IN INDUSTRIAL AND MUNICIPAL WASTEWATERS  

EPA Science Inventory

This report describes the systematic evaluation of a series of parameters leading to the development of a test procedure for 36 volatile priority pollutants in wastewaters. A study of the effect of pH, temperature, and residual chlorine on the aqueous stability of the compounds l...

287

Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) can react in the atmosphere to form organic nitrates, which serve as NOx (NO + NO2) reservoirs, impacting ozone and secondary organic aerosol production, the oxidative capacity of the atmosphere, and nitrogen availability to ecosystems. To examine the contributions of biogenic emissions and the formation and fate of organic nitrates in a forest environment, we simulated the oxidation of 57 individual BVOCs emitted from a rural mixed forest in northern Michigan. Key BVOC-oxidant reactions were identified for future laboratory and field investigations into reaction rate constants, yields, and speciation of oxidation products. Of the total simulated organic nitrates, monoterpenes contributed ~70% in the early morning at ~12 m above the forest canopy when isoprene emissions were low. In the afternoon, when vertical mixing and isoprene nitrate production were highest, the simulated contribution of isoprene-derived organic nitrates was greater than 90% at all altitudes, with the concentration of secondary isoprene nitrates increasing with altitude. Notably, reaction of isoprene with NO3 leading to isoprene nitrate formation was found to be significant (~8% of primary organic nitrate production) during the daytime, and monoterpene reactions with NO3 were simulated to comprise up to ~83% of primary organic nitrate production at night. Lastly, forest succession, wherein aspen trees are being replaced by pine and maple trees, was predicted to lead to increased afternoon concentrations of monoterpene-derived organic nitrates. This further underscores the need to understand the formation and fate of these species, which have different chemical pathways and oxidation products compared to isoprene-derived organic nitrates and can lead to secondary organic aerosol formation.

Pratt, K. A.; Mielke, L. H.; Shepson, P. B.; Bryan, A. M.; Steiner, A. L.; Ortega, J.; Daly, R.; Helmig, D.; Vogel, C. S.; Griffith, S.; Dusanter, S.; Stevens, P. S.; Alaghmand, M.

2012-11-01

288

Determination of the particle size distribution and chemical composition of semi-volatile organic compounds in atmospheric fine particles with a diffusion denuder sampling system  

NASA Astrophysics Data System (ADS)

Correct assessment of the factors associated with visibility impairment is dependent on accurate determination of the chemical composition as a function of size of particles present in the atmosphere. Collection of particles on a filter results in underestimation of particulate organic compounds due to losses from the semi-volatile organic fraction during sample collection, i.e. a "negative sampling artifact". These semi-volatile organic compounds lost from particles collected on a filter can be correctly measured using a diffusion denuder sampling system. This paper describes a multi-system, multi-channel, high-volume diffusion denuder sampler for the accurate determination of the particle size distribution and chemical composition of semi-volatile organic compounds in atmospheric fine particles. Data obtained in Provo, UT and Los Angeles, CA on the chemical composition and particle size distribution of semi-volatile organic compounds in atmospheric fine particles indicate that the majority of the semi-volatile organic compounds lost from particles during sampling were present in particles in the 0.4-0.8 ?m size range in the atmospheres sampled. Organic compounds lost from the particles during sampling include paraffinic compounds, aromatic compounds and organic acids and esters.

Tang, H.; Lewis, E. A.; Eatough, D. J.; Burton, R. M.; Farber, R. J.

289

Differentiating a Diverse Range of Volatile Organic Compounds with Polyfluorophore Sensors Built on a DNA Scaffold  

PubMed Central

Oligodeoxyfluorosides (ODFs) are short DNA-like oligomers in which DNA bases are replaced with fluorophores. A preliminary study reported that some sequences of ODFs were able to respond to a few organic small molecules in the vapor phase, giving a change in fluorescence. Here we follow up on this finding by investigating a larger range of volatile organic analytes, and a considerably larger set of sensors. A library of tetramer ODFs of 2401 different sequences was prepared using combinatorial methods, and was screened in air for fluorescence responses to a set of ten different volatile organics, including multiple aromatic and aliphatic compounds, acids and bases, varied functional groups and closely related structures. Nineteen responding sensors were selected and characterized; these were cross-screened against all ten analytes, and responses were measured qualitatively (by changes in color and intensity) and quantitatively (by measuring ?(R,G,B) values averaged over 5–6 sensor beads). The results show that sensor responses were diverse, with a single sensor responding differently to as many as eight of the ten analytes; multiple classes of responses were seen, including quenching, lighting up, and varied shifts in wavelength. Responses were strong, with raw ?(R,G,B) values of as high as >200 on a 256-unit scale and unamplified changes in many cases apparent to the naked eye. Sensors were identified that could distinguish clearly between even very closely related compounds such as acrolein and acrylonitrile. Statistical methods were applied to select a small set of four sensors that, as a pattern response, could distinguish between all ten analytes with high confidence. Sequence analysis of the full set of sensors suggested that sequence/order of the monomer components, and not merely composition, was highly important in the responses.

Samain, Florent; Dai, Nan; Kool, Eric T.

2011-01-01

290

Acid digestion of organic liquids  

Microsoft Academic Search

Laboratory studies on the destruction of liquid organic wastes by acid digestion are discussed. A variety of liquid waste types was tested, including those encountered in the nuclear industry as well as some organic liquids representative of non-nuclear industrial wastes. The liquids tested were vacuum pump oil, tri-n-butyl phosphate (TBP), normal paraffin hydrocarbon solvent (NPH), a mixture of 30 vol%

J. A. Partridge; G. P. Bosuego

1980-01-01

291

Intrinsic degradation of volatile fatty acids in laboratory-compacted clayey soil  

NASA Astrophysics Data System (ADS)

Volatile fatty acids (VFAs) represent the major organic constituent of landfill leachate and provide the greatest potential for leachate induced organic contamination of groundwater (e.g. as represented by an increase in the concentration of dissolved organic carbon and chemical oxygen demand). Long-term diffusion tests were performed for laboratory-compacted clayey soil plugs exposed to continuous supply of synthetic leachate containing VFAs. Significant microbial activity developed upon exposure of the soil's indigenous microorganisms to these degradable contaminants. The growth of heterotrophic aerobic bacteria (HAB, which include facultative anaerobes), sulfate reducing bacteria (SRB) and methanogenic bacteria carrying out fermentation and mineralization of the VFAs became evident after 30-50 days of testing. The maximum microbial counts of (2-8)×10 8 and (0.1-1)×10 8 cfu/g for HAB and SRB were localized in the soil layer at the interface with the source of organic and inorganic nutrients. Regardless of this rapid growth in microbial population, the VFA consumption was small and measurable only after a lag of 140-180 days. It is considered that this lag of otherwise readily degradable organic compounds (such as VFAs) persisted due to a combination of the effects of a high initial concentration of these acids (2.4 g/l as dissolved organic carbon, DOC) applied to carbon starved soil microorganisms and the small pore size of the compacted clay. Once the significant amounts of gas were generated from fermentation, conditions developed for improved mass transport and exchange of the nutrients and bacteria and the outcome of the intrinsic degradation was more apparent. The breakdown of VFAs that followed after the lag was localized near the top of the soil and was characterized by a short half-life of 0.75-5 days for DOC (total VFAs as dissolved organic carbon).

Hrapovic, L.; Rowe, R. K.

2002-10-01

292

Effect of source on net portal flux of glucose, lactate, volatile fatty acids and amino acids in the pig  

Microsoft Academic Search

The ileal digestibilities of maize starch and native pea starch do not differ. However maize starch is digested faster than pea starch and the ileal amino acid digestibility of a diet containing pea starch is lower. In the present study, the net portal fluxes of glucose, lactate, volatile fatty acids (VFA) and amino acids were measured for diets including 650

J. Van Der Meulen; J. G. M. Bakker; B. Smits; H. De Visser

1997-01-01

293

Continuous production of volatile fatty acids by acidogenesis of sugar beet vinasse  

Microsoft Academic Search

The present work deals with volatile fatty acids generation during the acidification of beet sugar vinasse. Two fixed?bed anaerobic reactors have been used for this purpose, at a fixed temperature of 30 °C. The daily output of acids ranged between 63 and 75 Kg.m, and the joint acid production amounted to 50–60 % butyric acid, 29–35 % acetic acid and

E. Sardinero; I. Schnabel; J. Garrido

1986-01-01

294

Evaluation of the separation characteristics of application-specific (volatile organic compounds) open-tubular columns for gas chromatography.  

PubMed

The solvation parameter model is used to characterize the separation characteristics of two application-specific open-tubular columns (Rtx-Volatiles and Rtx-VGC) and a general purpose column for the separation of volatile organic compounds (DB-WAXetr) at five equally spaced temperatures over the range 60-140 degrees C. System constant differences and retention factor correlation plots are then used to determine selectivity differences between the above columns and their closest neighbors in a large database of system constants and retention factors for forty-four open-tubular columns. The Rtx-Volatiles column is shown to have separation characteristics predicted for a poly(dimethyldiphenylsiloxane) stationary phase containing about 16% diphenylsiloxane monomer. The Rtx-VGC column has separation properties similar to the poly(cyanopropylphenyldimethylsiloxane) stationary phase containing 14% cyanopropylphenylsiloxane monomer DB-1701 for non-polar and dipolar/polarizable compounds but significantly different characteristics for the separation of hydrogen-bond acids. For all practical purposes the DB-WAXetr column is shown to be selectivity equivalent to poly(ethylene glycol) columns prepared using different chemistries for bonding and immobilizing the stationary phase. Principal component analysis and cluster analysis are then used to classify the system constants for the above columns and a sub-database of eleven open-tubular columns (DB-1, HP-5, DB-VRX, Rtx-20, DB-35, Rtx-50, Rtx-65, DB-1301, DB-1701, DB-200, and DB-624) commonly used for the separation of volatile organic compounds. A rationale basis for column selection based on differences in intermolecular interactions is presented as an aid to method development for the separation of volatile organic compounds. PMID:16996069

Poole, Colin F; Qian, Jing; Kiridena, Waruna; Dekay, Colleen; Koziol, Wladyslaw W

2006-11-17

295

The acid tolerance response of Salmonella typhimurium provides protection against organic acids.  

PubMed

Salmonella typhimurium encounters a variety of acid stress situations during pathogenesis and in the natural environment. These include the extreme low pH encountered in the stomach and a less acidic intestinal environment containing large amounts of organic weak acids (volatile fatty acids). The acid tolerance response (ATR) is a complex defence system that can minimize the lethal effects of extreme low pH (pH3). The data presented illustrate that the ATR can also defend against weak acids such as butyric, acetic or propionic acids. Although an acid shock of pH 4.4 induced the ATR, growth in subinhibitory concentrations of weak acids did not. Various mutations shown to affect tolerance to extreme acid conditions (pH 3) were tested for their effects on tolerance to weak acids. An rpoS mutant lacking the alternative sigma factor sigma s failed to protect cells against weak acids as well as extreme acid pH. The fur (ferric uptake regulator) and atp (Mg(2+)-dependent ATPase) mutants defective in extreme acid tolerance showed no defects in their tolerance to weak acids. Curiously, the atbR mutant that exhibits increased tolerance to extreme acid pH proved sensitive to weak acids. Several insertions that rendered cells sensitive to organic acids were isolated, all of which proved to be linked to the rpoS locus. PMID:8969516

Baik, H S; Bearson, S; Dunbar, S; Foster, J W

1996-11-01

296

Multisorbent Tubes for Collecting Volatile Organic Compounds in Spacecraft Air  

Microsoft Academic Search

The sampling capability of Tenax-TA tubes, used in the National Aeronautics and Space Administration's solid sorbent air sampler to trap and concentrate contaminants from air aboard spacecraft, was improved by incorporating two sorbents within the tubes. Existing tubes containing only Tenax-TA allowed highly volatile compounds to “break through” during collection of a 1.5 L air sample. First the carbon molecular

Marilyn L. Matney; Steve W. Beck; Thomas F. Limero; John T. James

2000-01-01

297

Recovery of several volatile organic compounds from simulated water samples: Effect of transport and storage  

USGS Publications Warehouse

Solutions containing volatile organic compounds were prepared in organic-free water and 2% methanol and submitted to two U.S. Geological Survey laboratories. Data from the determination of volatile compounds in these samples were compared to analytical data for the same volatile compounds that had been kept in solutions 100 times more concentrated until immediately before analysis; there was no statistically significant difference in the analytical recoveries. Addition of 2% methanol to the storage containers hindered the recovery of bromomethane and vinyl chloride. Methanol addition did not enhance sample stability. Further, there was no statistically significant difference in results from the two laboratories, and the recovery efficiency was more than 80% in more than half of the determinations made. In a subsequent study, six of eight volatile compounds showed no significant loss of recovery after 34 days.

Friedman, L. C.; Schroder, L. J.; Brooks, M. G.

1986-01-01

298

The development of a volatile organics concentrator for use in monitoring Space Station water quality  

NASA Technical Reports Server (NTRS)

A breadboard concept of a volatile organics concentrator (VOC) is manufactured and tested for optimized water-quality analysis in a space environment. The VOC system is attached to a gas chromatograph/mass spectrometer to analyze the volatile chemicals relevant to the operation of Space Station Freedom. The preliminary tests include: (1) comparisons with analyses based on direct on-column injections of standards; (2) analyses of iodinated volatile organics; (3) comparisons of nitrogen vs helium as the chromatography carrier gas; and (4) measurements of collection efficiency. The VOC can analyze EPA method-624 analytes at comparable detection using flame-ionization detection and can analyze volatile iodinated compounds. The breadboard has good reproducibility and can use nitrogen as a carrier gas; good results are noted for the collection and concentration levels and for water removal.

Bodek, Itamar; Ehntholt, Daniel J.; Stolki, Thomas J.; Valentine, James R.; Trabanino, Rudy; Webb, Johanna V.; Sauer, Richard L.

1991-01-01

299

A volatile organics concentrator for use in monitoring Space Station water quality  

NASA Technical Reports Server (NTRS)

The process used to identify, select, and design an approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment is discerned. The trade analysis leading to the recommended volatile organics concentrator (VOC) concept to be tested in a breadboard device is presented. The system covers the areas of gases, volatile separation from water, and water removal/gas chromatograph/mass spectrometer interface. Five options for potential use in the VOC and GC/MS system are identified and ranked, and also nine options are presented for separation of volatiles from the water phase. Seven options for use in the water removal/GC column and MS interface are also identified and included in the overall considerations. A final overall recommendation for breadboard VOC testing is given.

Ehntholt, Daniel J.; Bodek, Itamar; Valentine, James R.; Trabanino, Rudy; Vincze, Johanna E.; Sauer, Richard L.

1990-01-01

300

The Reduction of HNO3 to HONO by Volatile Organic Compounds Associated with Rush Hour Traffic  

NASA Astrophysics Data System (ADS)

Nitrous acid (HONO) is an important source of OH radicals in urban environments. However, the sources of HONO are not completely understood, which makes modeling urban atmospheric chemistry difficult. During a previous field study in Houston, TX a correlation was observed between increases in HONO and organic aerosol freshly emitted by motor vehicle traffic during morning rush hours (Ziemba et al., 2010). This source of HONO could not be explained by primary HONO emissions, and the hypothesis was drawn that the HONO was being formed from the reduction of HNO3 by the organic aerosols emitted by motor vehicles. To test this hypothesis, nitric acid (HNO3) was combined in a flow tube with aerosols made from automobile engine oil, which were used as a model for the organic aerosols emitted by rush hour traffic. Reduction of the HNO3 to HONO was observed, although the reaction was found to occur with the volatile organic carbon compounds (VOCs) found in the aerosol vapor, and not the particle surfaces. To explore this further Teflon raschig rings were added to the flow tube to increase surface area but the reaction was not enhanced, confirming the reaction to be homogeneous. The HONO formation observed ranged between 0.1 and 0.5 ppb hr-1 with a mean of 0.3±0.1 ppb hr-1, for typical nitric acid concentrations of 4-5 ppb and estimated concentrations of the reactive components in the engine oil vapor of between 200 and 300 ppt. The observations in this study compared well to the cited field study which observed formation rates between 0.05 and 0.5 ppb hr-1 with an average of 0.3±0.15 ppb hr-1. Water vapor was found to decrease the HONO formation rate by 0.1 ppb hr-1 for every1% of increase in the water mixing ratio. Reference Ziemba L.D., Dibb J.E., Griffin R.J., Anderson C.H., Whitlow S.I., Lefer B.L., Rappenglueck B., and Flynn J. (2010) Heterogeneous conversion of nitric acid to nitrous acid on the surface of primary organic aerosol in an urban atmosphere. Atmospheric Environment, 44, 4081-4089 (33). doi: 10.1016/j.atmosenv.2008.12.024. Available on the Internet at ://WOS:000282866300009.

Rutter, A. P.; Malloy, Q.; Scheuer, E.; Gutierrez, C.; Calzada, M.; Dibb, J. E.; Griffin, R. J.

2012-12-01

301

Volatile organics off-gassed among tobacco-exposed clothing fabrics.  

PubMed

This work evaluates the characteristics of short-term release of volatile and semi-volatile organic chemicals from clothing fabrics that are exposed to environmental tobacco smoke (ETS). Various fabrics were concurrently exposed to ETS in a controlled facility, and the chemicals off-gassed were sampled using solid phase micro-extraction coupled with GC/MS analysis. Toluene-reference concentration (TRC) was calculated for nine selected chemicals and compared. The number of chemicals identified from ETS-exposed fabrics ranged from 13 (polyester and acetate) to 32 (linen). All fabrics off-gassed formaldehyde, tetradecanoic acid and n-hexadecanoic acid, while seven out of eight fabrics emitted furfural, benzonitrile, naphthalene and decanal. Natural fibers of plant origin (cotton and linen) off-gassed higher concentrations (TRC>100 ?g/l) of chemicals that have low molecular weight (~100 or less) than did natural fibers of animal origin (wool and silk) and synthetic fibers. Conversely, wool and silk off-gassed more chemicals that are of high molecular weight (>200), such as TDA (TRC>100 ?g/l) and n-HDA (TRC>500 ?g/l), than did other fabrics. Fabric structure (for a particular material) significantly affects chemical off-gassing. Cotton typically used for polo shirt (knitted) off-gassed significantly (p<0.05) higher TRC for chemicals with molecular weight of ~100 (such as furfural) than did other cottons of woven style. The dyeing of fabric (white vs. black) had a limited effect on emission, while increasing contact time with ETS increased the intensity of chemical emissions. The mean TRC for cotton exposed for 12 min was nearly doubled than those exposed for 8min, but no difference existed for polyester. PMID:21852036

Chien, Yeh-Chung; Chang, Cheng-Ping; Liu, Zheng-Zhe

2011-10-15

302

Volatile organic compounds obtained by in vitro callus cultivation of Plectranthus ornatus Codd. (Lamiaceae).  

PubMed

Plectranthus spp (Lamiaceae) are plants of economic importance because they are sources of aromatic essential oils and are also cultivated and several species of this genus are used as folk medicines. This paper describes the effects of different concentrations of the 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-naphthaleneacetic acid (NAA) on the induction of callus from nodal segments of Plectranthus ornatus Codd and in the production of volatile organic compounds (monoterpenes and sesquiterpenes). The 20 and 40 day calli were subjected to solid phase micro extraction (HS-SPME) and submitted to GCMS analysis. Variations in VOCs between the samples were observed and, a direct relationship was observed between of the major constituent detected (?-terpinyl acetate) and the monoterpenes ?-thujene, ?-pinene, ?-pinene, camphene, sabinene and ?-limonene that were present in the volatile fractions. Besides ?-terpinyl acetate, isobornyl acetate and ?-limonene were also major constituents. Variations were observed in VOCs in the analyzed periods. The best cultivation media for the production of VOCs was found to be MS0 (control). Moderate success was achieved by treatment with 2.68 µM and 5:37 µM NAA (Group 2). With 2,4-D (9.0 µM), only the presence of ?-terpinyl acetate and isocumene were detected and, with 2.26 µM of 2,4-D was produced mainly ?-terpinyl acetate, ?-thujene and ?-caryophyllene (16.2%). The VOC profiles present in P. ornatus were interpreted using PCA and HCA. The results permitted us to determine the best cultivation media for VOC production and, the PCA and HCA analysis allowed us to recognize four groups among the different treatments from the compounds identified in this set of treatments. PMID:24064448

Passinho-Soares, Helna C; Meira, Paloma R; David, Juceni P; Mesquita, Paulo R R; do Vale, Ademir E; de M Rodrigues, Frederico; de P Pereira, Pedro A; de Santana, José Raniere F; de Oliveira, Fabio S; de Andrade, Jailson B; David, Jorge M

2013-01-01

303

Volatile organics off-gassed among tobacco-exposed clothing fabrics  

Microsoft Academic Search

This work evaluates the characteristics of short-term release of volatile and semi-volatile organic chemicals from clothing fabrics that are exposed to environmental tobacco smoke (ETS). Various fabrics were concurrently exposed to ETS in a controlled facility, and the chemicals off-gassed were sampled using solid phase micro-extraction coupled with GC\\/MS analysis. Toluene-reference concentration (TRC) was calculated for nine selected chemicals and

Yeh-Chung Chien; Cheng-Ping Chang; Zheng-Zhe Liu

2011-01-01

304

The consequences of volatile organic compound mediated bacterial and fungal interactions  

Microsoft Academic Search

Microbial interactions via infochemicals are fundamental to the development of spatial distribution and activity variations\\u000a in ecosystems. Microorganisms produce a wide range of infochemicals, frequently secondary metabolites, most of which are soluble\\u000a and many volatile. Volatile organic compounds (VOCs) have been identified in soil atmospheres and related to community structure\\u000a and function. VOC profiles produced by microorganisms are consistent, relating

R. E. Wheatley

2002-01-01

305

Semi-volatile secondary organic aerosol in urban atmospheres: meeting a measurement challenge  

Microsoft Academic Search

Ammonium nitrate and semi-volatile organic compounds are significant components of fine particles in urban atmospheres. These components, however, are not properly determined with current US EPA accepted methods such as the PM2.5 FRM or other single filter samplers due to significant losses of semi-volatile material (SVM) from particles collected on the filter during sampling. Continuous PM2.5 mass measurements are attempted

Delbert J. Eatough; Russell W. Long; William K. Modey; Norman L. Eatough

2003-01-01

306

HS-SPME analysis of volatile organic compounds of coniferous needle litter  

Microsoft Academic Search

The composition of volatile emission of Scots pine (Pinus sylvestris) and spruce (Picea exelsa) litter was studied by gas chromatography-mass spectrometry (GC-MS) and samples were collected by solid-phase microextraction (SPME) method. The list of identified compounds includes over 60 organic substances of different classes. It was established that volatile emission contain not only components of essential oils of pine and

V. A. Isidorov; V. T. Vinogorova; K. Rafa?owski

2003-01-01

307

Modeling organic aerosols in a megacity: potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol formation  

SciTech Connect

It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of traditional anthropogenic and biogenic VOC precursors. In this study, the 3D regional air quality model CHIMERE is applied to quantify the contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic vapors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to explicitly include the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ("ROB") and Grieshop et al. (2009) ("GRI") are compared and evaluated against surface and aircraft measurements. For the first time, 3D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, but also against and oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (3-6 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. The predicted anthropogenic POA levels are found to agree within 20% with the observed HOA concentrations for both the ROB and GRI simulations, consistent with the interpretation of the emissions inventory by previous studies. The impact of biomass burning POA within the city is underestimated in comparison to the AMS BBOA, presumably due to insufficient nighttime smoldering emissions. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The production from anthropogenic and biomass burning S/IVOC represents 40-60% of the total SOA at the surface during the day and is somewhat larger than that from aromatics, especially at the T1 site at the edge of the city. The downwind SOA production from the continued multi-generation S/IVOC oxidation products actively continues. Similar to aircraft observations, the predicted OA/DCO ratio for the ROB case increases from 20-30 mg sm-3 ppm-1 up to 60-70 mg sm-3 ppm-1 between a fresh and 1-day aged air mass, while the GRI case produces a 30-40% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R2=0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA evolution with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the very important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for improvements in current parameterizations. We note that other proposed pathways of SOA formation such as formation from very volatile species like glyoxal were not included in our simulations, which can also contribute SOA mass and especially increase the O/C ratio.

Hodzic, Alma; Jimenez, Jose L.; Madronich, Sasha; Canagaratna, M. R.; DeCarlo, Peter F.; Kleinman, Lawrence I.; Fast, Jerome D.

2010-06-21

308

A Novel Method for Analyzing Microbially Affiliated Volatile Organic Compounds in Soil Environments  

NASA Astrophysics Data System (ADS)

A concerted, international effort by citizens, governments, industries and educational systems is necessary to address the myriad environmental issues that face us today. The authors of this paper concentrate on soil environments and, specifically, the methods currently used to characterize them. The ability to efficiently and effectively monitor and characterize various soils is desired, allows for the study, supervision, and protection of natural and cultivated ecosystems, and may assist stakeholders in meeting governmentally-imposed environmental standards. This research addresses soil characterization by a comparison of four methods that emphasize a combination of microbial community and metabolic measures: BIOLOG, fatty acid methyl-ester analysis (FAME), descriptive physical and chemical analysis (moisture content, pH, carbon content, nutrient content, and grain size), and the novel soil-microbe volatile organic compound analysis (SMVOC) presented in this work. In order to achieve the method comparison, soils were collected from three climatic regions (Bahamas, Michigan, and Mississippi), with three samples taken from niche ecosystems found at each climatic region (a total of nine sites). Of interest to the authors is whether or not an investigation of microbial communities and the volatile organic compounds (VOCs) produced by microbial communities from nine separate soil ecosystems provides useful information about soil dynamics. In essence, is analysis of soil-derived VOCs using gas chromatography-mass spectrometry (GC-MS) an effective method for characterizing microbial communities and their metabolic activity of soils rapidly and accurately compared with the other three traditional characterization methods? Preliminary results suggest that VOCs in each of these locales differ with changes in soil types, soil moisture, and bacterial community. Each niche site shows distinct patterns in both VOCs and BIOLOG readings. Results will be presented to show the efficacy of the SMVOC approach and the statistical alignment of the VOC and community measures.

Ruhs, C. V.; McNeal, K. S.

2010-12-01

309

Environmental Aspects of Two Volatile Organic Compound Groundwater Treatment Designs at the Rocky Flats Site - 13135  

SciTech Connect

DOE's Rocky Flats Site in Colorado is a former nuclear weapons production facility that began operations in the early 1950's. Because of releases of hazardous substances to the environment, the federally owned property and adjacent offsite areas were placed on the CERCLA National Priorities List in 1989. The final remedy was selected in 2006. Engineered components of the remedy include four groundwater treatment systems that were installed before closure as CERCLA-accelerated actions. Two of the systems, the Mound Site Plume Treatment System and the East Trenches Plume Treatment System, remove low levels of volatile organic compounds using zero-valent iron media, thereby reducing the loading of volatile organic compounds in surface water resulting from the groundwater pathway. However, the zero-valent iron treatment does not reliably reduce all volatile organic compounds to consistently meet water quality goals. While adding additional zero-valent iron media capacity could improve volatile organic compound removal capability, installation of a solar powered air-stripper has proven an effective treatment optimization in further reducing volatile organic compound concentrations. A comparison of the air stripper to the alternative of adding additional zero-valent iron capacity to improve Mound Site Plume Treatment System and East Trenches Plume Treatment System treatment based on several key sustainable remediation aspects indicates the air stripper is also more 'environmentally friendly'. These key aspects include air pollutant emissions, water quality, waste management, transportation, and costs. (authors)

Michalski, Casey C.; DiSalvo, Rick; Boylan, John [Stoller LMS Team, 11025 Dover Street, Suite 1000, Westminster, CO 80021 (United States)] [Stoller LMS Team, 11025 Dover Street, Suite 1000, Westminster, CO 80021 (United States)

2013-07-01

310

Identification of volatile hydrocarbons as mobile source tracers for fine-particulate organics  

Microsoft Academic Search

Several volatile organic compounds (VOCs) have been identified as candidates for tracers of fine particulate carbon and Extractable Organic Matter (EOM) from mobile sources. The identification resulted from a multiple screening procedure in which the ambient concentrations of a candidate VOC were first required to have both a high correlation with ambient concentrations of fine particulate Pb, a well established

Roy B. Zweidinger; Robert K. Stevens; Charles W. Lewis; Hal Westburg

1990-01-01

311

LABORATORY AND FIELD EVALUATION OF THE SEMI-VOST (SEMI-VOLATILE ORGANIC SAMPLING TRAIN) METHOD  

EPA Science Inventory

Laboratory studies and a second field evaluation have been completed to assess the performance of the Semi-Volatile Organic Sampling Train (Semi-VOST) method for measuring concentrations of principal organic hazardous constituents (POHCs) with boiling points greater than 100 deg ...

312

The dynamic adsorption behaviour of volatile organic compounds on activated carbon honeycomb monoliths  

Microsoft Academic Search

Adsorption offers an efficient technology for removing volatile organic compounds (VOCs) from air pollution sources. Often activated carbons (ACs) are employed owing to their large specific surface areas, high micropore volumes, rapid adsorption capabilities and selectivity towards organic molecules compared to water vapour or air. However, when large volumes of gas have to be treated pressure drop limitations may arise

M. Yates; J. Blanco; M. A. Martín-Luengo

2002-01-01

313

Spatial and Temporal Volatile Organic Compound Measurements in New England: Key Insight on Sources and Distributions  

Microsoft Academic Search

Volatile organic compounds (VOCs) in the atmosphere act as precursors in the formation of tropospheric ozone and their emissions and oxidation products can contribute to secondary organic aerosol formation and growth. In examining their effects on regional chemistry and pollution events, considerable uncertainties exist in our understanding of the relative contributions from different sources and classes of compounds as well

B. C. Sive; M. L. White; R. S. Russo; Y. Zhou; J. L. Ambrose; K. Haase; H. Mao; R. W. Talbot

2010-01-01

314

SOIL SORPTION OF VOLATILE AND SEMIVOLATILE ORGANIC COMPOUNDS IN A MIXTURE  

EPA Science Inventory

Studies were conducted to evaluate lipophilicity as a predictor of sorption for a mixture of organic compounds with high vapor pressures commonly present at hazardous waste sites. orption partition coefficients (Kp) for the mixture of 16 volatile and semivolatile organic compound...

315

VALIDATION OF THE VOLATILE ORGANIC SAMPLING TRAIN (VOST) PROTOCOL. VOLUME 2. FIELD VALIDATION PHASE  

EPA Science Inventory

With the development of the Volatile Organic Sampling Train (VOST) Protocol (February 1984) to measure organic emissions from hazardous waste incinerators, a wide variety of compounds have been collected and analyzed. Because its use is currently being recommended by regulatory a...

316

Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana.  

PubMed

Volatile organic compounds (VOC) were extracted and identified from plant growth-promoting fungi (PGPF), Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography-mass spectrometry (GC-MS). Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp.) significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst). Subsequently, m-cresol and methyl benzoate (MeBA) were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR) against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA) or Jasmonic acid (JA)/ethylene (ET) signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases. PMID:24475190

Naznin, Hushna Ara; Kiyohara, Daigo; Kimura, Minako; Miyazawa, Mitsuo; Shimizu, Masafumi; Hyakumachi, Mitsuro

2014-01-01

317

Gas partitioning of dissolved volatile organic compounds in the vadose zone: Principles, temperature effects and literature review  

Microsoft Academic Search

Enthalpy and entropy of volatilization from dilute aqueous solutions for 26 volatile organic compounds (VOCs) have been determined using Henry`s Law values reported in published literature. Based on the linearity of van`t Hoff plots, for the temperature ranges common in soils, the differences in heat capacities of volatilization for reactants and products are very small for the VOCs studied. When

John W. Washington

1996-01-01

318

Volatile acetic acid and formaldehyde emission from plywood treated with boron compound  

Microsoft Academic Search

The effects of plywood on formaldehyde and volatile acetic acid emissions treated with borax and boric acid were investigated. The treated plywood samples were manufactured by using two different methods; each veneer was first impregnated by a dipping method before the first group of plywood was manufactured. The second group of plywood panels was produced by adding preservatives (borax, boric

S. Colak; G. Colakoglu

2004-01-01

319

HS-SPME/GC-MS analysis of volatile and semi-volatile organic compounds emitted from municipal sewage sludge.  

PubMed

The aim of the research involved identification and semi-quantitative determination of unknown volatile and semi-volatile organic compounds emitted to air by sewage sludge formed in the process of municipal wastewater treatment in a sewage treatment plant. Samples taken directly after completion of the technological process as well as the sludge stored on the premise of the sewage treatment plant were analyzed. A simple method using off-line headspace solid-phase microextraction combined with gas chromatography-mass spectrometry has been proposed for extraction and detection of organic pollutants. For reliable identification of compounds, combination of two independent parameters: mass spectra and linear temperature programmed retention indices were employed. Over 170 compounds of different structure were identified including aliphatic and aromatic hydrocarbons, alcohols, esters, carbonyls, as well as sulfur, nitrogen, and chlorine containing compounds. The prevailing substances included: ethyl ether, n-hexane, p-xylene, o-xylene, mesitylene, m-ethylbenzene, limonene, n-decane, n-undecane, and n-dodecane. A few compounds such as methanetiol, dimethyl polisulfide, octaatomic sulfur, phthalic anhydride, and indoles were identified in the sludge for the first time. PMID:21688031

Kotowska, Urszula; ?alikowski, Maciej; Isidorov, Valery A

2012-05-01

320

Variable emissions of microbial volatile organic compounds (MVOCs) from root-associated fungi isolated from Scots pine  

Microsoft Academic Search

Soils emit a large variety of volatile organic compounds. In natural ecosystems, measurements of microbial volatile organic compound (MVOC) exchange rates between soil and atmosphere are difficult due to e.g. the spatial heterogeneity of the belowground organisms, and due to the many potential sources for the same compounds. We measured in laboratory conditions the MVOC emission rates and spectra of

Jaana Bäck; Hermanni Aaltonen; Heidi Hellén; Maija K. Kajos; Johanna Patokoski; Risto Taipale; Jukka Pumpanen; Jussi Heinonsalo

2010-01-01

321

Effects of NOx on the volatility of secondary organic aerosol from isoprene photooxidation.  

PubMed

The effects of NOx on the volatility of the secondary organic aerosol (SOA) formed from isoprene photooxidation are investigated in environmental chamber experiments. Two types of experiments are performed. In HO2-dominant experiments, organic peroxy radicals (RO2) primarily react with HO2. In mixed experiments, RO2 reacts through multiple pathways, including with NO, NO2, and HO2. The volatility and oxidation state of isoprene SOA are sensitive to and exhibit a nonlinear dependence on NOx levels. Depending on the NOx levels, the SOA formed in mixed experiments can be of similar or lower volatility compared to that formed in HO2-dominant experiments. The dependence of SOA yield, volatility, and oxidation state on the NOx level likely arises from gas-phase RO2 chemistry and succeeding particle-phase oligomerization reactions. The NOx level also plays a strong role in SOA aging. While the volatility of SOA in mixed experiments does not change substantially over time, SOA becomes less volatile and more oxidized as oxidation progresses in HO2-dominant experiments. PMID:24471688

Xu, Lu; Kollman, Matthew S; Song, Chen; Shilling, John E; Ng, Nga L

2014-02-18

322

A Standardized Sampling Procedure for the Determination of Volatile Organic Compounds (VOC) Determined in Snow Samples  

NASA Astrophysics Data System (ADS)

Snow samples were collected from different semi-remote and urban environments using a standardized sampling procedure in order to minimize sampling errors. Samples were collected in pre-cleaned amber glass and sterile HDPE containers. Glass bottles and all non-sterilized equipment were washed with low nutrient detergent, acid washed and rinsed with ultra-pure water. Samples were collected using pre-sterilized or acid-washed sampling tools and blanks, consisting of ultra-pure water, which were treated identically to the collected samples in to monitor contamination from sampling equipment and the different types of containers. Analysis for VOC was carried out with a previously described, but modified solid phase micro-extraction (SPME) pre-concentration method and determination of compounds using gas-chromatography with mass spectrometric detection (GC-MS) (1). Low concentrations required the use of larger sample volumes and splitless injection mode. Samples analyzed were collected in and around Montreal, Quebec (45.28 N/73.45 W) at Mont-Saint Hilaire (altitude: 415 m a.s.l.), Downtown Montreal and Parc Tremblant. We will present and compare results from all sites, and the implication for atmospheric processes will be discussed. References (1) Kos G, Ariya PA (2004), Determination of Volatile Organic Compounds in Snow Using Solid Phase Micro Extraction, Eos Trans. AGU, 85 (47), Fall Meet. Suppl., Abstract A11B-53

Kos, G.; Ariya, P. A.

2005-12-01

323

Determination of volatile organic profiles and photochemical potentials from chemical manufacture process vents.  

PubMed

The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para-terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS >ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA-42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g(-1) VOC (PTA). The significance of this O3 yield is discussed. PMID:17608005

Hsu, Yi-Chyun; Chen, Shan-Kun; Tsai, Jiun-Horng; Chiang, Hung-Lung

2007-06-01

324

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef  

NASA Astrophysics Data System (ADS)

Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% ?-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+?-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

Ahn, D. U.; Nam, K. C.

2004-09-01

325

Multisorbent tubes for collecting volatile organic compounds in spacecraft air  

NASA Technical Reports Server (NTRS)

The sampling capability of Tenax-TA tubes, used in the National Aeronautics and Space Administration's solid sorbent air sampler to trap and concentrate contaminants from air aboard spacecraft, was improved by incorporating two sorbents within the tubes. Existing tubes containing only Tenax-TA allowed highly volatile compounds to "break through" during collection of a 1.5 L air sample. First the carbon molecular sieve-type sorbents Carboxen 569 and Carbosieve S-III were tested for their ability to quantitatively trap the highly volatile compounds. Breakthrough volumes were determined with the direct method, whereby low ppm levels of methanol or Freon 12 in nitrogen were flowed through the sorbent tubes at 30 mL/min, and breakthrough was detected by gas chromatography. Breakthrough volumes for methanol were about 9 L/g on Carboxen 569 and 11 L/g on Carbosieve S-III; breakthrough volumes for Freon 12 were about 7 L/g on Carboxen 569 and > 26 L/g on Carbosieve S-III. Next, dual-bed tubes containing either Tenax-TA/Carbosieve S-III, Tenax-TA/Carboxen 569, or Carbotrap/Carboxen 569 to a 10-component gas mixture were exposed, in dry and in humidified air (50% relative humidity), and percentage recoveries of each compound were determined. The Tenax-TA/Carboxen 569 combination gave the best overall recoveries (75-114% for the 10 compounds). Acetaldehyde had the lowest recovery (75%) of the 10 compounds, but this value was still an improvement over either the other two sorbent combinations or the original single-sorbent tubes.

Matney, M. L.; Beck, S. W.; Limero, T. F.; James, J. T.

2000-01-01

326

Thermal engine driven heat pump for recovery of volatile organic compounds  

DOEpatents

The present invention relates to a method and apparatus for separating volatile organic compounds from a stream of process gas. An internal combustion engine drives a plurality of refrigeration systems, an electrical generator and an air compressor. The exhaust of the internal combustion engine drives an inert gas subsystem and a heater for the gas. A water jacket captures waste heat from the internal combustion engine and drives a second heater for the gas and possibly an additional refrigeration system for the supply of chilled water. The refrigeration systems mechanically driven by the internal combustion engine effect the precipitation of volatile organic compounds from the stream of gas.

Drake, Richard L. (Schenectady, NY)

1991-01-01

327

Volatile and intermediate-volatility organic compounds in sub-urban Paris: variability, origin and importance for SOA formation  

NASA Astrophysics Data System (ADS)

Measurements of gaseous and particulate organic carbon were performed during the MEGAPOLI experiments, in July 2009 and January-February 2010, at the SIRTA observatory in sub-urban Paris. Measurements of primary and secondary volatile organic compounds (VOCs), of both anthropogenic and biogenic origins, including for the first time C12-C16 n-alkanes of intermediate volatility (IVOCs), suspected to be efficient precursors of secondary organic aerosol (SOA). The time series of gaseous carbon are generally consistent with times series of particulate organic carbon at regional scales and are clearly affected by meteorology and air mass origin. Concentration levels of anthropogenic VOCs in urban and sub-urban Paris were surprisingly low (2-963 ppt) compared to other megacities worldwide and to rural continental sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between the urban and sub-urban Paris sites, showing the regional extent of anthropogenic sources of similar composition. Contrary to other primary anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations in winter (< 5 ppt) compared to summer (13-27 ppt) in agreement with a gas-particle partitioning in favor of their transfer to the particle phase in winter. Higher concentrations of most oxygenated VOCs in winter (18-5984 ppt) suggest their dominant primary anthropogenic origin. The respective role of primary anthropogenic gaseous compounds in regional SOA formation was investigated by estimating the SOA mass concentration expected from the anthropogenic VOCs and IVOCs (I / VOCs) measured at SIRTA. From an approach based on emissions inferred from the I / VOC concentrations times the SOA formation yields', the so-called integrated approach conducted in this study, 46% of the SOA measured at SIRTA is explained by our measured concentrations of I / VOC, with 10% explained by only C12-C16 IVOCs. From results of an alternative time-resolved approach, the explained variability of the SOA concentrations is improved when the IVOCs are taken into account. Both approaches, which are based on ambient measurements of particular I / VOCs, emphasize the importance of the intermediate volatility compounds in the SOA formation, and support previous results from chamber experiments and modeling studies. The approaches results support the need to make systematic the IVOCs speciated measurement during field campaigns.

Ait-Helal, W.; Borbon, A.; Sauvage, S.; de Gouw, J. A.; Colomb, A.; Gros, V.; Freutel, F.; Crippa, M.; Afif, C.; Baltensperger, U.; Beekmann, M.; Doussin, J.-F.; Durand-Jolibois, R.; Fronval, I.; Grand, N.; Leonardis, T.; Lopez, M.; Michoud, V.; Miet, K.; Perrier, S.; Prévôt, A. S. H.; Schneider, J.; Siour, G.; Zapf, P.; Locoge, N.

2014-02-01

328

A Comparative study of Volatile Organic Compounds from two desert plant species growing in Southern Arizona  

NASA Astrophysics Data System (ADS)

Throughout their lives, plants are subjected to a multitude of stressors, ranging from herbivory to changes in weather. In order to survive, plants have created an arsenal of volatile organic compounds (VOCs), including green leaf volatiles (GLVs) and aromatic compounds, to combat these stressors. In this study, two plant species, Baccharis salicifolia (Seep willow) and Dodonaea viscosa (Hopbush) were examined for isoprenoids, GLVs, and aromatic compound emissions. Although, the species are not related, they should share some emitted compounds as they can be seen growing in the same environment, though the majority of the emitted compounds should remain unique to each species type. Both the Seep willow, sampled in Catalina State Park, and the Hopbush, sampled at Biosphere 2, were sampled using a Teflon bag enclosure connected to an apex lite air-sampling device and a thermal desorption (TD) tube, which was used to collect the emitted compounds. TD tube samples were analyzed using a Unity 2 thermal desorption system, which was directly connected to a 5975C series gas chromatograph/electron impact mass spectrometer with a triple-axis detector. The major compounds emitted from the Seep willow were GLVs (Octanal, Decanal, and Nonanal) and aromatics (Benzoic acid, Benzaldehyde, 1,2,3-Trifluorobenzene, and Acetophenone). The major compounds emitted from the Hopbush were isoprene and monoterpenes (1R-?-Pinene, Limonene, and ?-Phellandrene.) Our results show the two species emit completely different compounds from each other, which could indicate adaptive differences. The Hopbush may be a hardier species better adapted to the Arizona environment as isoprene and monoterpenes have been indicated in thermo tolerance. GLVs on the other hand indicate the Seep willow is under severe stress.

Paasche, K. M.; Meyers, K.; Jardine, K.

2012-12-01

329

Atmospheric PM and volatile organic compounds released from Mediterranean shrubland wildfires  

NASA Astrophysics Data System (ADS)

Wildfires produce a significant release of gases and particles affecting climate and air quality. In the Mediterranean region, shrublands significantly contribute to burned areas and may show specific emission profiles. Our objective was to depict and quantify the primary-derived aerosols and precursors of secondary particulate species released during shrubland experimental fires, in which fire-line intensity values were equivalent to those of moderate shrubland wildfires, by using a number of different methodologies for the characterization of organic and inorganic compounds in both gas-phase and particulate-phase. Emissions of PM mass, particle number concentrations and organic and inorganic PMx components during flaming and smouldering phases were characterized in a field shrubland fire experiment. Our results revealed a clear prevalence of K+ and SO42- as inorganic ions released during the flaming-smouldering processes, accounting for 68-80% of the inorganic soluble fraction. During the residual-smouldering phases, in addition to K+ and SO42-, Ca2+ was found in significant amounts probably due the predominance of re-suspension processes (ashes and soil dust) over other emission sources during this stage. Concerning organic markers, the chromatograms were dominated by phenols, n-alkanals and n-alkanones, as well as by alcohol biomarkers in all the PMx fractions investigated. Levoglucosan was the most abundant degradation compound with maximum emission factors between 182 and 261 mg kg-1 in PM2.5 and PM10 respectively. However, levoglucosan was also observed in significant amounts in the gas-phase. The most representative organic volatile constituents in the smoke samples were alcohols, carbonyls, acids, monocyclic and bicyclic arenes, isoprenoids and alkanes compounds. The emission factors obtained in this study may contribute to the validation and improvement of national and international emission inventories of this intricate and diffuse emission source.

Garcia-Hurtado, Elisa; Pey, Jorge; Borrás, Esther; Sánchez, Pilar; Vera, Teresa; Carratalá, Adoración; Alastuey, Andrés; Querol, Xavier; Vallejo, V. Ramon

2014-06-01

330

Secondary organic aerosol formation from intermediate-volatility organic compounds: cyclic, linear, and branched alkanes.  

PubMed

Intermediate volatility organic compounds (IVOCs) are an important class of secondary organic aerosol (SOA) precursors that have not been traditionally included in chemical transport models. A challenge is that the vast majority of IVOCs cannot be speciated using traditional gas chromatography-based techniques; instead they are classified as an unresolved complex mixture (UCM) that is presumably made up of a complex mixture of branched and cyclic alkanes. To better understand SOA formation from IVOCs, a series of smog chamber experiments was conducted with different alkanes, including cyclic, branched, and linear compounds. The experiments focused on freshly formed SOA from hydroxyl (OH) radical-initiated reactions under high-NO(x) conditions at typical atmospheric organic aerosol concentrations (C(OA)). SOA yields from cyclic alkanes were comparable to yields from linear alkanes three to four carbons larger in size. For alkanes with equivalent carbon numbers, branched alkanes had the lowest SOA mass yields, ranging between 0.05 and 0.08 at a C(OA) of 15 ?g m(-3). The SOA yield of branched alkanes also depends on the methyl branch position on the carbon backbone. High-resolution aerosol mass spectrometer data indicate that the SOA oxygen-to-carbon ratios were largely controlled by the carbon number of the precursor compound. Depending on the precursor size, the mass spectrum of SOA produced from IVOCs is similar to the semivolatile-oxygenated and hydrocarbon-like organic aerosol factors derived from ambient data. Using the new yield data, we estimated SOA formation potential from diesel exhaust and predict the contribution from UCM vapors to be nearly four times larger than the contribution from single-ring aromatics and comparable to that of polycyclic aromatic hydrocarbons after several hours of oxidation at typical atmospheric conditions. Therefore, SOA from IVOCs may be an important contributor to urban OA and should be included in SOA models; the yield data presented in this study are suitable for such use. PMID:22823284

Tkacik, Daniel S; Presto, Albert A; Donahue, Neil M; Robinson, Allen L

2012-08-21

331

Effect of design parameters in horizontal flow constructed wetland on the behaviour of volatile fatty acids and volatile alkylsulfides  

Microsoft Academic Search

A pilot-scale horizontal flow constructed wetland (HFCW) system planted with common reed (Phragmites sp.) was constructed to study how hydraulic loading rate (HLR), aspect ratio, water depth, and granular medium affect to the fate of several organic matter degradation intermediates namely, acetic acid (HAc), isovaleric acid (Isoval), and dimethylsulfide (DMS). ANOVA statistical analysis performed on the data set of 8

Yuming Huang; Laura Ortiz; Paula Aguirre; Joan García; Rafael Mujeriego; Josep M. Bayona

2005-01-01

332

Significance and treatment of volatile organic compounds in water supplies  

SciTech Connect

Chapter 1 covers the statutory and regulatory basis for the control of chemicals in drinking water and the 1986 Amendments to the Safe Drinking Water Act. Chapter 2 reviews: (1) the nature and extent of groundwater contamination, and (2) management controls. Chapter 3 describes research methods for determination of aqueous VOCs. Chapter 4 reviews the EPA-approved analytical methods for VOC analysis in drinking water. Chapter 5 presents sampling and analysis procedures to minimize volatilization loss. Chapter 6 reviews past and present approaches of fiber optics to measure VOCs in groundwater. Chapter 7 reviews the national surveys of VOCs in ground and surface waters. Chapter 9 presents a conceptual overview of VOC transport in groundwater. Chapter 10 discusses the physical-chemical properties and fate of VOCs using the fugacity approach. Chapter 11 focuses on biologically mediated transformations that affect the fate of VOCs in the environment. Chapter 12 reviews the theory and applications of VOC removal from drinking water by adsorption. Chapter 13 presents a detailed model for a packed tower aeration (PTA) system. Chapter 14 describes oxidative treatment methods that convert VOCs to relatively harmless substances. Chapter 15 reviews research, being conducted by EPA's Drinking Water Research Division. Chapter 16 describes point-of-use/point-of-entry systems technology. Chapter 17 presents an economic analysis of GA and PTA. The remaining five chapters discuss the risks involved in water treatment for VOCs. Separate abstracts are processed for 21 chapters in this book for inclusion in the appropriate data bases.

Ram, N.M.; Christman, R.F.; Cantor, K.P. (ed.)

1990-01-01

333

Branched-chain and aromatic amino acid catabolism into aroma volatiles in Cucumis melo L. fruit  

PubMed Central

The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty acids, carotenoids, amino acids, and terpenes. Although amino acids are known precursors of aroma compounds in the plant kingdom, the initial steps in the catabolism of amino acids into aroma volatiles have received little attention. Incubation of melon fruit cubes with amino acids and ?-keto acids led to the enhanced formation of aroma compounds bearing the side chain of the exogenous amino or keto acid supplied. Moreover, L-[13C6]phenylalanine was also incorporated into aromatic volatile compounds. Amino acid transaminase activities extracted from the flesh of mature melon fruits converted L-isoleucine, L-leucine, L-valine, L-methionine, or L-phenylalanine into their respective ?-keto acids, utilizing ?-ketoglutarate as the amine acceptor. Two novel genes were isolated and characterized (CmArAT1 and CmBCAT1) encoding 45.6?kDa and 42.7?kDa proteins, respectively, that displayed aromatic and branched-chain amino acid transaminase activities, respectively, when expressed in Escherichia coli. The expression of CmBCAT1 and CmArAT1 was low in vegetative tissues, but increased in flesh and rind tissues during fruit ripening. In addition, ripe fruits of climacteric aromatic cultivars generally showed high expression of CmBCAT1 and CmArAT1 in contrast to non-climacteric non-aromatic fruits. The results presented here indicate that in melon fruit tissues, the catabolism of amino acids into aroma volatiles can initiate through a transamination mechanism, rather than decarboxylation or direct aldehyde synthesis, as has been demonstrated in other plants.

Gonda, Itay; Bar, Einat; Portnoy, Vitaly; Lev, Shery; Burger, Joseph; Schaffer, Arthur A.; Tadmor, Ya'akov; Gepstein, Shimon; Giovannoni, James J.; Katzir, Nurit; Lewinsohn, Efraim

2010-01-01

334

PERVAPORATIVE REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM MULTICOMPONENT AQUEOUS MIXTURES  

Microsoft Academic Search

The present study concerns with the separation of binary and ternary water–organics mixtures by pervaporation using different organophilic membranes (i.e., PERVAP-1060—polydimethylsiloxane, PERVAP-1070—zeolite filled polydimethylsiloxane, PEBAX-4033—polyether block amide). The following binary and ternary liquid mixtures were investigated: water–methyl acetate; water–ethyl acetate; water–butyl acetate, water–methyl t-butyl ether (MTBE), and water–methanol–MTBE. The organic components of these mixtures can be found in the wastewaters

Wojciech Kujawski; Renata Roszak

2002-01-01

335

Acid volatile sulfide and simultaneously extracted metals in superficial sediments from Baihua Lake, China  

NASA Astrophysics Data System (ADS)

The bioavailability of five divalent cationic heavy metals (Pb, Cd, Cu, Zn and Ni) in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals (SEMs) to acid volatile sulfide (AVS). Atomic absorption spectrometry (AAS) and X-ray powder diffraction (XRD) were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 ?mol/g (dry weight). The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 ?mol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.

Zhang, Jiping; Hu, Jiwei; Huang, Xianfei; Shen, Wei; Jin, Mei; Fu, Liya; Jin, Xiaofei

2013-09-01

336

PATTERN RECOGNITION/EXPERT SYSTEM FOR MASS SPECTRA OF VOLATILE TOXIC AND OTHER ORGANIC COMPOUNDS  

EPA Science Inventory

A system based on principles of pattern recognition has been developed for identifying toxic and other volatile organic pollutants in complex environmental samples. t interprets the most commonly used monitoring data, mass spectral data, and produces a class designation, an estim...

337

INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS.  

EPA Science Inventory

INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS. A.S. Bale*; P.J. Bushnell; C.A. Meacham; T.J. Shafer Neurotoxicology Division, NHEERL, ORD, US Environmental Protection Agency, Research Triangle Park, NC, USA Toluene (TOL...

338

Volatile organic compound emissions from automobile refinishing: Background information for promulgated standards. Final report  

SciTech Connect

A final rule for the regulation of volatile organic compounds (VOC) from automobile refinishing is being promulgated under the authority of Section 183(e) of the Clean Air Act. This document contains comments received from the public, and the EPA`s responses to these comments.

NONE

1998-08-01

339

DEVELOPMENT OF A SAMPLER FOR PARTICULATE-ASSOCIATED AND LOW VOLATILITY ORGANIC POLLUTANTS IN RESIDENTIAL AIR  

EPA Science Inventory

The report describes the development of a sampler for particulate-associated and low volatility organic pollutants in residential air. The performance of the sampler inlet, which is compatible with the proposed PM-10 regulations for particulate sampling, is documented under a var...

340

Risk assessment of exposure to volatile organic compounds in different indoor environments  

Microsoft Academic Search

The lifetime cancer risks of exposure of cooks and food service workers, office workers, housewives, and schoolchildren in Hong Kong to volatile organic compounds (VOCs) in their respective indoor premises during normal indoor activities were assessed. The estimated cancer risk for housewives was the highest, and the second-highest lifetime cancer risk to VOC exposure was for the groups of food

H. Guo; S. C Lee; L. Y Chan; W. M Li

2004-01-01

341

TEST METHODS FOR THE DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN CONSUMER PRODUCTS  

EPA Science Inventory

The paper discusses two test methods for determining volatile organic compounds (VOCs) in consumer products. he development of test methods for determining VOC emissions from consumer products has been identified by many states as the highest priority research activity in the con...

342

CHARACTERIZATION OF EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM INTERIOR ALKYD PAINT  

EPA Science Inventory

Alkyd paint continues to be used indoors for application to wood trim, cabinet surfaces, and some kitchen and bathroom walls. Paint may represent a significant source of volatile organic compounds (VOCs) indoors depending on the frequency of use and amount of surface paint. The U...

343

Selective sensing of volatile organic compounds using novel conducting polymer-metal nanoparticle hybrids  

Microsoft Academic Search

Conducting polymer-metal nanoparticle hybrids, fabricated by assembling metal nanoparticles on top of functionalized conducting polymer film surfaces using conjugated linker molecules, enable the selective sensing of volatile organic compounds (VOCs). In these conducting polymer-metal nanoparticle hybrids, selectivity is achieved by assembling different metals on the same conducting polymer film. This eliminates the need to develop either different polymers chemistries or

Sreeram Vaddiraju; Karen K. Gleason

2010-01-01

344

MODELING OF MULTICOMPONENT PERVAPORATION FOR REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM WATER  

EPA Science Inventory

A resistance in series model was used to study the pervaporation of multiple volatile organic compounds (VOCs) water mixtures. ermeation experiments were carried out for four membranes and three VOCs. he membrane permeability were calculated in terms of the resistance in series m...

345

A GLOBAL INVENTORY OF VOLATILE ORGANIC COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES  

EPA Science Inventory

As part of an effort to assess the potential impacts associated with global climate change, the U.S. Environmental Protection Agency's Office of Research and Development is supporting global atmospheric chemistry research by developing global scale estimates of volatile organic c...

346

IDENTIFICATION OF VOLATILE HYDROCARBONS AS MOBILE SOURCE TRACERS FOR FINE PARTICULATE ORGANICS  

EPA Science Inventory

Several volatile organic compounds (VOCs) have been identified as candidates for tracers of fine particulate carbon and EOM from mobile sources. he identification resulted from a multiple screening procedure in which the ambient concentrations of a candidate VOC were first requir...

347

VOLATILE ORGANIC HYDROCARBON AND ALDEHYDE COMPOSITION IN RALEIGH, NORTH CAROLINA DURING THE 1985 WOODSMOKE STUDY  

EPA Science Inventory

Initial field tests for collection of volatile organic hydrocarbons and aldehydes under EPA's Integrated Air Cancer Project (IACP) were held in Raleigh, NC during the winter of 1985. Sampling was conducted during 12 hour (7:00-7:00) daytime or nighttime periods. Hydrocarbons were...

348

Volatile Organic Hydrocarbon and Aldehyde Composition in Raleigh, North Carolina during the 1985 Woodsmoke Study.  

National Technical Information Service (NTIS)

Initial field tests for collection of volatile organic hydrocarbons and aldehydes under EPA's Integrated Air Cancer Project (IACP) were held in Raleigh, NC during the winter of 1985. Sampling was conducted during 12 hour (7:00-7:00) daytime or nighttime p...

R. Zweidinger D. Dropkin F. Stump S. Tejada R. Drago

1987-01-01

349

PERFORMANCE EVALUATION MATERIALS FOR THE ANALYSIS OF VOLATILE ORGANIC CONTAMINANTS IN SOILS: A PRELIMINARY ASSESSMENT  

EPA Science Inventory

During an evaluation of field portable gas chromatographs (GC), site-specific performance evaluation materials (PEM) were prepared and used as quality control samples. lean soils from two contaminated sites were spiked with various volatile organic compounds. he PEM were shipped ...

350

Development of the colorimetric sensor array for detection of explosives and volatile organic compounds in air  

NASA Astrophysics Data System (ADS)

In the framework of the research project 'Xsense' at the Technical University of Denmark (DTU) we are developing a simple colorimetric sensor array which can be useful in detection of explosives like DNT and TNT, and identification of volatile organic compounds in the presence of water vapor in air. The technology is based on an array of chemo-responsive dyes immobilized on a solid support. Upon exposure to the analyte in suspicion the dye array changes color. Each chosen dye reacts chemo selectively with analytes of interest. A change in a color signature indicates the presence of unknown explosives and volatile organic compounds (VOCs). We are working towards the selection of dyes that undergo color changes in the presence of explosives and VOCs, as well as the development of an immobilization method for the molecules. Digital imaging of the dye array before and after exposure to the analytes creates a color difference map which gives a unique fingerprint for each explosive and volatile organic compound. Such sensing technology can be used to screen for relevant explosives in a complex background as well as to distinguish mixtures of volatile organic compounds distributed in gas phase. This sensor array is inexpensive, and can potentially be produced as single use disposable.

Kostesha, N. V.; Alstrøm, T. S.; Johnsen, C.; Nilesen, K. A.; Jeppesen, J. O.; Larsen, J.; Jakobsen, M. H.; Boisen, A.

2010-04-01

351

Biosensor using immobilized Chlorella microalgae for determination of volatile organic compounds  

Microsoft Academic Search

A biosensor using Chlorella microalgae immobilized on the membrane of an oxygen electrode has been designed to determine volatile organic compounds (VOC) in the form of aerosols. A homemade controlled atmosphere chamber is constructed for perchloroethylene detection. Monitoring of perchloroethylene is obtained by the measurement of the oxygen production during the algae photosynthetic process.

Martine Naessens; Canh Tran-Minh

1999-01-01

352

COLD TRAPPING OF VOLATILE ORGANIC COMPOUNDS ON FUSED SILICA CAPILLARY COLUMNS  

EPA Science Inventory

A 30m, 0.25mm ID, fused silica capillary column at temperatures from -60 to -100C has been shown to be a quantitative trap for organic compounds with volatilities ranging from that of 1.1-dichloroethene to that of chlorobenzene. This type of 'whole column cryotrapping' provided s...

353

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM A LOWLAND TROPICAL WET FOREST IN COSTA RICA  

EPA Science Inventory

Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCS) at a lowland tropical wet forest site in Costa Rica. Ten of the species. examined emitted substantial quantities of isoprene. These species accounted for 35-50% of the total bas...

354

Levels and composition of volatile organic compounds on commuting routes in Detroit, Michigan  

Microsoft Academic Search

Vehicle emissions can constitute a major share of ambient concentrations of many volatile organic compounds (VOCs) and other air pollutants in urban areas. Especially high concentrations may occur at curbsides, vehicle cabins, and other microenvironments. Such levels are not reflected by monitoring at fixed sites. This study reports on measurements of VOCs made from buses and cars in Detroit, MI.

Stuart A Batterman; Chung-Yu Peng; James Braun

2002-01-01

355

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM DESERT VEGETATION OF THE SOUTHWESTERN U.S.  

EPA Science Inventory

Thirteen common plant species in the Mojave and Sonoran Desert regions of the western United States were tested for emissions of biogenic non-methane volatile organic compounds (BVOCs). Only two of the species examined emitted isoprene at rates of 10 µgCg?1 ...

356

COMPARISON OF SAMPLING METHODS FOR SEMI-VOLATILE ORGANIC CARBON ASSOCIATED WITH PM 2.5  

EPA Science Inventory

This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders ...

357

Control of volatile organic emissions from petroleum liquid storage in external floating roof tanks  

Microsoft Academic Search

This report provides the necessary guidance for development of regulations limiting emissions of volatile organic compounds (VOC) from storage of petroleum liquids in external floating roof tanks. Reasonably available control technology (RACT) is defined in this document; cost analysis for RACT is included for evaluating the cost effectiveness of controlling external floating roof tank sources.

R. K. Burr; K. C. Brothers; J. G. Wright

1978-01-01

358

INHIBITION OF HUMAN A7 NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS BY THE VOLATILE ORGANIC SOLVENT TRICHLOROETHYLENE.  

EPA Science Inventory

Volatile organic compounds such as toleune, trichloroethylene and perchloroethylene are potent and reversible blockers of voltage-gated calcium current in nerve growth factor (NGF)-differentiated pheochromocytoma (PC12) cells. It is hypothesized that effects of VOCs on ICa contri...

359

Innovative Technologies And Vadose Zone Treatment Of Chlorinated Volatile Organic Compounds - Case Study  

Microsoft Academic Search

Over the last 10 years a mix of innovative and conventional characterization techniques has been used to assess the contamination of vadose zone sediments beneath the pilot-scale test facility known as TNX at the Savannah River Site (SRS) in South Carolina. Shallow soils and groundwater beneath the TNX facility are contaminated with chlorinated volatile organic compounds (CVOCs), trichloroethylene (TCE), carbon

JAY V. NOONKESTER; RALPH L. NICHOLS; Kenneth L. Dixon

2005-01-01

360

Modeling volatile organic chemical removal by in situ soil mixing\\/steam stripping  

Microsoft Academic Search

In situ soil mixing coupled with hot air\\/steam injection is a means for overcoming low-permeability conditions and treating soils contaminated with volatile and semivolatile organic chemicals (VOCs and SVOCs). A process model was developed to simulate heat and mass transport during combined in situ mixing and thermal treatment of unsaturated soils contaminated with low levels of VOCs. The soil treatment

J. S. Gierke; O. M. Reyes; R. L. Siegrist

1992-01-01

361

Computer modeling of environmental chamber measurements of maximum incremental reactivities of volatile organic compounds  

Microsoft Academic Search

A detailed atmospheric photochemical mechanism which had been previously used in model calculations for developing ozone reactivity scales for volatile organic compounds (VOCs) was evaluated by comparing its predictions with measurements of incremental reactivities in an environmental chamber system. An updated version of this mechanism is also described and evaluated. The experiments consisted of determining the effects of adding representative

William P. L. Carter

1995-01-01

362

Sample preparation for the analysis of volatile organic compounds in air and water matrices  

Microsoft Academic Search

This review summarizes literature data from the past 5 years on new developments and\\/or applications of sample preparation methods for analysis of volatile organic compounds (VOC), mainly in air and water matrices. Novel trends in the optimization and application of well-established airborne VOC enrichment techniques are discussed, like the implementation of advanced cooling systems in cryogenic trapping and miniaturization in

Kristof Demeestere; Jo Dewulf; Bavo De Witte; Herman Van Langenhove

2007-01-01

363

CONTROL OF VOLATILE ORGANIC CONTAMINANTS IN GROUNDWATER BY IN-WELL AERATION  

EPA Science Inventory

At a 0.1 mgd well contaminated with several volatile organic compounds (VOCs), principally trichloroethylene (TCE), several in-well aeration schemes were evaluated as control technologies. The well was logged by the USGS to define possible zones of VOC entry. A straddle packer an...

364

Major sources of exposure to benzene and other volatile organic chemicals  

Microsoft Academic Search

The major sources of human exposure to about a dozen volatile organic chemicals (VOCs) have recently been identified. For nearly every chemical, the major sources of exposure are completely different from the major sources of emissions. This finding implies that current environmental regulations and control strategies are misdirected. Important sources of exposure are typically not regulated in any way, whereas

Lance Wallace

1990-01-01

365

FINAL REPORT: MEMBRANE-MEDIATED EXTRACTION AND BIODEGRADATION OF VOLATILE ORGANIC COMPOUNDS FROM AIR  

EPA Science Inventory

The report describes feasibility tests of a two-step strategy for air pollution control applicable to exhaust air contaminated with volatile organic compounds (VOCs) from painting aircraft. In the first step, the VOC-contaminated air passes over coated, polypropylene, hollow-fibe...

366

REASSESSMENT OF BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS IN THE ATLANTA AREA  

EPA Science Inventory

The paper discusses a reassessment of biogenic volatile organic compound (BVOC) emissions in the Atlanta area, using a new system for specific tree genera at hourly and county levels. (NOTE: Localized estimates of BVOC emissions are important inputs for photochemical oxidant simu...

367

Patterns in volatile organic compound emissions along a savanna-rainforest gradient in central Africa  

Microsoft Academic Search

In temperate regions the chemistry of the lower troposphere is known to be significantly affected by biogenic volatile organic compounds (VOCs) emitted by plants. The chemistry of the lower troposphere over the tropics, however, is poorly understood, in part because of the considerable uncertainties in VOC emissions from tropical ecosystems. Present global VOC models predict that base emissions of isoprene

L. F. Klinger; J. Greenberg; A. Guenther; G. Tyndall; P. Zimmerman; J.-M. Moutsamboté; D. Kenfack

1998-01-01

368

VOLATILE ORGANIC COMPOUNDS IN THE AMBIENT ATMOSPHERE OF THE NEW JERSEY, NEW YORK AREA  

EPA Science Inventory

From 1979 through 1981 data were collected on selected volatile organics in the ambient atmosphere of New Jersey and New York. The sites selected included urban, suburban rural, and industrial areas: Newark, Rutherford, South Amboy, Elizabeth, Camden and Batsto Village in New Jer...

369

Characterization and Health Risk Assessment of Volatile Organic Compounds in Gas Service Station Workers  

Microsoft Academic Search

Gas service station workers who work near volatile organic compounds (VOCs) sources, such as gasoline vapor emissions, and motor vehicle exhausts, may be exposed to highly elevated VOCs levels. This study investigates air samples from gas service stations in Thailand to evaluate the health risks following inhalation exposure. Personal air samplings were obtained at nine gas service stations in Chonburi,

Duangduan Yimrungruang; Voravit Cheevaporn; Herbert F. Helander

370

Importance of volatile organic compounds photochemistry over a forested area in central Greece  

Microsoft Academic Search

The impact of biogenic volatile organic compound (BVOC) on the chemical composition of the boundary layer in a valley-forested site of central Greece is investigated by using a chemical box model able to simulate ?- and ?-pinene and isoprene photochemistry in the troposphere. The model assimilates the meteorological conditions and mixing ratios of long-lived species observed during the AEROBIC field

Kostas Tsigaridis; Maria Kanakidou

2002-01-01

371

Distribution of volatile organic compounds during the combustion process in coal-fired power stations  

Microsoft Academic Search

This study concerns the distribution of volatile organic compounds (VOC) emitted during combustion processes in coal-fired power stations. Thermal desorption technique was employed to analyse VOC concentrations in gaseous emissions (trapped onto Carbotrap B sorbent) and solid samples (coal, fly ash and slag). An empirical parameter (Y) was employed to evaluate the relationships between the compounds emitted during a real

G Fernández-Mart??nez; P López-Mah??a; S Muniategui-Lorenzo; D Prada-Rodr??guez; E Fernández-Fernández

2001-01-01

372

Identification and transport investigation of microbial volatile organic compounds in full-scale stud cavities  

Microsoft Academic Search

An experimental project was conducted to investigate mold products, namely spores and volatile organic compounds (VOCs) in the cavity of full-scale stud wall assemblies. Twenty specimens were constructed and tested to inquire the capacity of wall cavities to restrain mold products, emanating from studs with 10% of their surface covered with mold, from penetrating into the indoor space. The tests

Caroline Hachem; Paul Fazio; Jiwu Rao; Karen Bartlett; Yogendra P. Chaubey

2009-01-01

373

Volatile organic compounds in urban and industrial atmospheres: measurement techniques and data analysis  

Microsoft Academic Search

Main results of 62 volatile organic compounds (VOCs) 'continuous' on-line measurement obtained at the Air Quality Monitoring Station sited at the School of Engineering of Bilbao (Northern Spain) are presented. The system has been put into operation between 1997 and 2001 in an area influenced by urban and industrial emissions. Initially, the measurement method and data validation process are described

Marino Navazo; Nieves Durana; Lucio Alonso; J. Antonio García; J. Luis Ilardia; M. Carmen Gómez; Gozton Gangoiti

2003-01-01

374

SOLID PHASE MICROEXTRACTION: MEASUREMENT OF VOLATILE ORGANIC COMPOUNDS (VOCs) IN DHAKA CITY AIR POLLUTION  

Microsoft Academic Search

A solid phase microextraction (SPME) technique was applied for the sampling of volatile organic compounds (VOCs) in ambient air polluted by two stroke autorickshaw engines and automobile exhausts in Dhaka city, Bangladesh. Analysis was carried out by capillary gas chromatography (GC) and GC-mass spectrometry (MS). The methodology was tested by insitu sampling of an aromatic hydrocarbon mixture gas standard with

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

2002-01-01

375

The relationship between soil contaminated with volatile organic compounds and indoor air pollution  

Microsoft Academic Search

The relationship between soil contaminated with volatile organic compounds and indoor air quality was examined. Measurements in the soil and indoor air were taken in 77 houses built on different types of contaminated soil. In seven houses, the influence of soil contamination on indoor air quality was detected. Repeated measurements showed that the contribution to indoor air pollution was consistent,

J. Kliest; T. Fast; J. S. M. Boleij; H. van de Wiel; H. Bloemen

1989-01-01

376

Artificial intelligence methods for selection of an optimized sensor array for identification of volatile organic compounds  

Microsoft Academic Search

We have investigated two artificial intelligence (AI)-based approaches for the optimum selection of a sensor array for the identification of volatile organic compounds (VOCs). The array consists of quartz crystal microbalances (QCMs), each coated with a different polymeric material. The first approach uses a decision tree classification algorithm to determine the minimum number of features that are required to classify

Robi Polikar; Ruth Shinar; Lalita Udpa; Marc D. Porter

2001-01-01

377

Comparison of methods for determination of volatile organic compounds in drinking water  

Microsoft Academic Search

Comparison of four methods including liquid–liquid extraction (LLE), direct aqueous injection (DAI), purge and trap (PAT) and head space (HS) were carried out in this work for determination of volatile organic compounds (VOCs) including trihalomethanes (THMs) in drinking water. This comparison is made especially to show the advantages and disadvantages and specifically the different detection limits (DL) that can be

Spyros K Golfinopoulos; Themistokles D Lekkas; Anastasia D Nikolaou

2001-01-01

378

Ambient, indoor and personal exposure relationships of volatile organic compounds in Mexico City Metropolitan Area  

Microsoft Academic Search

Air pollution standards and control strategies are based on ambient measurements. For many outdoor air pollutants, individuals are closer to their sources (especially traffic) and there are important indoor sources influencing the relationship between ambient and personal exposures. This paper examines the relationship between volatile organic compounds (VOCs) measured at central site monitoring stations and personal exposures in the Mexico

Paulina I Serrano-Trespalacios; Louise Ryan; John D Spengler

2004-01-01

379

Migration of volatile organic compounds from attached garages to residences: A major exposure source  

Microsoft Academic Search

Vehicle garages often contain high concentrations of volatile organic compounds (VOCs) that may migrate into adjoining residences. This study characterizes VOC concentrations, exposures, airflows, and source apportionments in 15 single-family houses with attached garages in southeast Michigan. Fieldwork included inspections to determine possible VOC sources, deployment of perfluorocarbon tracer (PFT) sources in garages and occupied spaces, and measurements of PFT,

Stuart Batterman; Chunrong Jia; Gina Hatzivasilis

2007-01-01

380

Accumulation and effect of volatile organic compounds in closed life support systems  

Microsoft Academic Search

Bioregenerative life support systems (BLSS) being considered for long duration space missions will operate with limited resupply and utilize biological systems to revitalize the atmosphere, purify water, and produce food. The presence of man-made materials, plant and microbial communities, and human activities will result in the production of volatile organic compounds (VOCs). A database of VOC production from potential BLSS

G. W. Stutte; R. M. Wheeler

1997-01-01

381

Internal Standards: A Source of Analytical Bias For Volatile Organic Analyte Determinations  

EPA Science Inventory

The use of internal standards in the determination of volatile organic compounds as described in SW-846 Method 8260C introduces a potential for bias in results once the internal standards (ISTDs) are added to a sample for analysis. The bias is relative to the dissimilarity betw...

382

SCREENING PROCESSED MILK FOR VOLATILE ORGANIC COMPOUNDS USING VACUUM DISTILLATION/GAS CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

An adaptation of Office of Solid Waste and Emergency Response' Test Methods for Evaluating Solid Waste Physical/Chemical Methods (SW-846) method 8261 to analyze milk for an expanded list of volatile organic compounds is presented. The milk matriz exhibits a strong affinity for o...

383

BEHAVIOR AND DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN SOIL: A LITERATURE REVIEW  

EPA Science Inventory

This report is a comprehensive literature review that presents and assesses research results that pertain to the problems and inconsistencies observed in the sampling and analysis of soil volatile organic compounds (VOC) by SW-846 method 5030 (purge and trap) for sample preparati...

384

Separation and concentration of volatile organic contaminants by activated carbon cloth for cryogenic recovery  

Microsoft Academic Search

New air quality control regulations and economics are causing the development of new devices or the optimization of existing technologies for control of toxic emissions from industrial sources. Volatile organic contaminants (VOCs) account for 47%, and non-halogenated VOCs account for 36% of these toxic emissions. For these emissions, under the 1990 Clean Air Act Amendments (CAAA), the United States Environmental

M. Lordgooei; K. R. Carmichael; T. W. Kelly

1996-01-01

385

Ambient volatile organic compound (VOC) concentrations around a petrochemical complex and a petroleum refinery  

Microsoft Academic Search

Air samples were collected between September 2000 and September 2001 in Izmir, Turkey at three sampling sites located around a petrochemical complex and an oil refinery to measure ambient volatile organic compound (VOC) concentrations. VOC concentrations were 4–20-fold higher than those measured at a suburban site in Izmir, Turkey. Ethylene dichloride, a leaded gasoline additive used in petroleum refining and

Eylem Cetin; Mustafa Odabasi; Remzi Seyfioglu

2003-01-01

386

DEVELOPMENT OF AN ANALYSIS METHOD FOR TOTAL NONMETHANE VOLATILE ORGANIC CARBON EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

The accurate measurement of the total nonmethane volatile organic carbon emissions from stationary sources is critical to characterizing many industrial processes and for regulating according to the Clean Air Act. urrent methods are difficult to use and the ability to do performa...

387

SUPERCRITICAL FLUID EXTRACTION OF SEMI-VOLATILE ORGANIC COMPOUNDS FROM PARTICLES  

EPA Science Inventory

A nitrogen oxide flux chamber was modified to measure the flux of semi-volatile organic compounds (SVOCs). Part of the modification involved the development of methods to extract SVOCs from polyurethane foam (PUF), sand, and soil. Breakthroughs and extraction efficiencies were ...

388

Spatial Gradients and Source Apportionment of Volatile Organic Compounds Near Roadways  

EPA Science Inventory

Concentrations of 55 volatile organic compounds (VOCs) are reported near a highway in Raleigh, NC (traffic volume of approximately 125,000 vehicles/day). Levels of VOCs generally decreased exponentially with perpendicular distance from the roadway 10-100m). The EPA Chemical Mass ...

389

NATURAL VOLATILE ORGANIC SUBSTANCES AND THEIR EFFECT ON AIR QUALITY IN THE UNITED STATES (REVIEW)  

EPA Science Inventory

Large quantities of volatile organic substances are emitted from mobile and stationary sources in the United States. When the US, east of 105 west longitude is divided into 80 by 80 km grids, most of these grid areas east of the Mississippi River and many west of the river, have ...

390

Measurement of volatile organic compounds by the US Environmental Protection Agency Compendium Method TO17  

Microsoft Academic Search

An evaluation of performance criteria for US Environmental Protection Agency Compendium Method TO-17 for monitoring volatile organic compounds (VOCs) in air has been accomplished. The method is a solid adsorbent-based sampling and analytical procedure including performance criteria for four merit parameters. These are: (1) the method detection limit (MDL); (2) the method precision; (3) the agreement between two samples taken

William A McClenny; Maribel Colón

1998-01-01

391

FLARES AS A MEANS OF DESTROYING VOLATILE ORGANIC AND TOXIC COMPOUNDS  

EPA Science Inventory

The paper discusses the use of flares to destroy volatile organic and toxic compounds. Flares are used to destroy industrial gases from which the heating cannot be economically recovered. Results of an EPA investigation of overall flare combustion efficiency and specific compound...

392

ASSESSMENT OF NATURAL VOLATILE ORGANIC SUBSTANCES AND THEIR EFFECT ON AIR QUALITY IN THE UNITED STATES  

EPA Science Inventory

This research brief is a summary of the extensive review and critical analysis of the literature on natural volatile organic substances, sometimes referred to as biogenic hydrocarbons, and an assessment of that body of scientific information. The review is reported separately (Na...

393

Medical Costs and Lost Productivity from Health Conditions at Volatile Organic Compound-Contaminated Superfund Sites  

Microsoft Academic Search

This paper estimates the health costs at Superfund sites for conditions associated with volatile organic compounds (VOCs) in drinking water. Health conditions were identified from published literature and registry information as occurring at excess rates in VOC-exposed populations. These health conditions were: (1) some categories of birth defects, (2) urinary tract disorders, (3) diabetes, (4) eczema and skin conditions, (5)

Jeffrey A. Lybarger; Russell Lee; David P. Vogt; Ralph M. Perhac; Robert F. Spengler; David R. Brown

1998-01-01

394

A POLYMER-CERAMIC COMPOSITE MEMBRANE FOR RECOVERING VOLATILE ORGANIC COMPOUNDS FROM WASTEWATERS BY PERVAPORATION  

EPA Science Inventory

A composite membrane was constructed on a porous ceramic support from a block copolymer of styrene and butadiene (SBS). It was tested in a laboratory pervaporation apparatus for recovering volatile organic compounds (VOCs) such a 1,1,1-trichloroethane (TCA) and trichloroethylene ...

395

ANALYSIS OF AMBIENT POLAR VOLATILE ORGANIC COMPOUNDS USING CHEMICAL IONIZATION -- ION TRAP DETECTOR  

EPA Science Inventory

The current approach to measuring trace levels of volatile organic compounds (VOCs) in ambient air requires cryogenic trapping of the analytes, followed by thermal desorption and low-temperature refocussing onto a column for analysis by capillary gas chromatography/mass spectrome...

396

Activated carbon cloth adsorption-cryogenic system to recover toxic volatile organic compounds  

Microsoft Academic Search

There is an emergent need to reduce the emissions of toxic volatile organic compounds (VOCs) to the atmosphere. One strategy to reduce the emissions of VOCs from point sources is to use air pollution control devices on the sources' discharge streams. This paper describes the development of a new activated carbon cloth (ACC) adsorption system that is integrated with cryogenic

Mehrdad Lordgooei; Kelly R. Carmichael; Terrance W. Kelly; Mark J. Rood; Susan M. Larson

1996-01-01

397

Adsorption and Regeneration on Activated Carbon Fiber Cloth for Volatile Organic Compounds at Indoor Concentration Levels  

Microsoft Academic Search

There are increasing concerns about indoor volatile organic compounds (VOCs) regarding their health effects and frequent occurrence. Adsorption using granular activated carbon (GAC) is a safe methodology for removing VOCs from indoor air. Although GAC has been widely used to remove VOCs from indoor air, the use of activated carbon fiber cloth (ACFC) is a promising substitute to the conventional

Meng Yao; Qiong Zhang; David W. Hand; David Perram; Roy Taylor; Mridul Gautam; Nigel Clark; Thomas Spencer; Daniel Carder; Thomas Balon; Paul Moynihan; Joshua Fu; David Streets; Carey Jang; Jiming Hao; Kebin He; Litao Wang; Qiang Zhang; Jan Paca; Martin Halecky; Mark Fitch; David Williams; William Potter; William Clarkson; Dee Sanders; John Stevens; Hazem El-Zanan; Barbara Zielinska; Lynn Mazzoleni; D. Hansen; Hyun-Sun Kim; Seung-Muk Yi; Eric Edgerton; Gary Casuccio; Rick Saylor; Traci Lersch; Benjamin Hartsell; John Jansen; Roger Wayson; Gregg Fleming; Ralph Iovinelli; Hans Grimm; Delbert Eatough

2009-01-01

398

Decomposition of volatile organic compounds and nitric oxide by nonthermal plasma discharge processes  

Microsoft Academic Search

Two types of nonthermal plasma processes such as pulsed corona discharge and dielectric barrier discharge were investigated for the decomposition of volatile organic compounds and nitric oxide. The performance equation of the plasma reactor was derived with the assumption that the decomposition rate of the pollutant is directly proportional to the concentration of the pollutant and the discharge power. From

Young Sun Mok; Chang Mo Nam; Moo Hyun Cho; In-Sik Nam

2002-01-01

399

Adsorption characteristics of trace volatile organic compounds in gas streams onto activated carbon fibers  

Microsoft Academic Search

The adsorption characteristics of activated carbon fibers (ACF) prepared from phenolic precursors were examined. Three ACF with specific surface areas of 900, 1610, and 2420 m[sup 2]\\/g were used to determine the adsorption of volatile organic compounds (VOC) over a range of concentrations in air or nitrogen gas streams. Gravimetric adsorption was used both to determine the ACF effective pore

K. L. Foster; R. G. Fuerman; J. Economy; S. M. Larson; M. J. Rood

2009-01-01

400

Applicability of adsorption equations to argon, nitrogen and volatile organic compound adsorption onto activated carbon  

Microsoft Academic Search

This research evaluates adsorption equations for argon, nitrogen, and volatile organic compound adsorption onto several commercially available activated carbons that represented a broad range of pore volume character, from predominantly microporous to predominantly mesoporous. For all these carbons, both the recently introduced (Paulson PD, Cannon FS, submitted to Carbon) Modified Freundlich equation and the Dubinin–Astakhov equation accurately characterized adsorption behavior

Paul D. Paulsen; Brian C. Moore; Fred S. Cannon

1999-01-01

401

Concentrations of volatile organic compounds in the passenger side and the back seat of automobiles  

Microsoft Academic Search

The in-vehicle volatile organic compound (VOC) concentrations during commutes have previously been measured in only one single interior sampling location, considering a sample collected in the single interior location as representative of overall VOC concentrations within an automobile. The present study evaluated if the potential differences in VOC concentrations occur in the automobiles' interior during idling and commuting under different

WAN-KUEN JO; KUN-HO PARK

1999-01-01

402

FIELD EVALUATION OF VOLATILE ORGANIC COMPOUND REMOVAL EFFICIENCY FOR FULL-SCALE CARBON ADSORPTION SYSTEMS  

EPA Science Inventory

Six full-scale, fixed-bed carbon adsorption systems were tested for vapor-phase volatile organic compound removal efficiency. Solvents used in the systems included methyl ethyl ketone, isopropyl acetate, tetrahydrofuran and toluene. One year after the first tests, repeat testing ...

403

EVALUATION OF INNOVATIVE LOW-VOLATILE ORGANIC COMPOUND (VOC) INDUSTRIAL MAINTENANCE (IM) COATINGS  

EPA Science Inventory

The paper discusses a field evaluation of the feasibility of using alternative low-volatile organic compound (VOC) coatings to replace higher-VOC coatings. he evaluation includes chemical, performance, and outdoor exposure testing. he feasibility of five alternative coatings for ...

404

Laboratory investigations of the hydroxyl radical-initiated oxidation of atmospheric volatile organic compounds  

Microsoft Academic Search

The hydroxyl radical (OH) is one of the most important oxidants in the atmosphere, because reaction with OH is the dominant atmospheric fate of most trace atmospheric species. OH is intimately involved in a complex non-linear photochemical pathway involving anthropogenic and biogenic emissions of volatile organic compounds (VOCs) and nitrogen oxides that are emitted from vehicular exhaust and industrial emissions.

Deepali Vimal

2008-01-01

405

COMPARISON OF TWO FIELD SAMPLING PROCEDURES (EN CORE AND FIELD METHANOL EXTRACTION) FOR VOLATILE ORGANIC COMPOUNDS  

EPA Science Inventory

In-situ Lasagna technology was recently evaluated at a contaminated site at Offutt Air Force Base. The site was contaminated with low levels (< 30 mg/kg) of volatile organic compounds (VOCs). Originally, researchers planned to use field methanol extraction for both pre- and pos...

406

Volatile organic compounds in snow in the Quebec-Windsor Corridor  

Microsoft Academic Search

Volatile organic compounds (VOC) were determined in snow to investigate the role of the snowpack as an exchange medium for atmospherically active compounds of anthropogenic and biogenic origin. The major question was which VOC species occur in snow and how the species identity and selected concentrations are related to the sampling area and environmental conditions. Samples were collected using a

G. Kos; P. A. Ariya

2010-01-01

407

Continuous determination of volatile organic compounds in the atmosphere by an automated gas chromatographic system  

Microsoft Academic Search

A fully automated gas chromatographic system has been developed for the continuous determination of trace levels of 54 selected volatile organic compounds (VOCs) in the atmosphere, with a short time resolution. The method is based on the preconcentration of an air sample using a multibed collection tube (Carbotrap B, Carboxen 1000, Carboxen 1001) at ambient temperature, by thermal desorption, and

Noriko Yamamoto; Hideki Okayasu; Takamititsu Hiraiwa; Satoru Murayama; Tuneaki Maeda; Masatoshi Morita; Koji Suzuki

1998-01-01

408

Determinants of exposure to volatile organic compounds in four Oklahoma cities  

Microsoft Academic Search

To begin to develop generalized models for estimating personal exposure to ambient air pollutants within diverse populations, the design of the Oklahoma Urban Air Toxics Study incorporated eight dichotomous macroenvironmental and household factors that were hypothesized to be potential determinants of exposure. Personal, indoor, and outdoor samples of volatile organic compounds (VOCs) were collected over 24-h monitoring periods in 42

Margaret L Phillips; Nurtan A Esmen; Thomas A Hall; Robert Lynch

2005-01-01

409

AMBIENT LEVEL VOLATILE ORGANIC COMPOUND (VOC) MONITORING USING SOLID ADSORBANTS - RECENT U.S. EPA STUDIES  

EPA Science Inventory

Ambient air spiked with 1-10 ppbv concentrations of 41 toxic volatile organic compounds (VOCs) listed in U.S. Environmental Protection Agency (EPA) Compendium Method TO-14A was monitored using solid sorbents for sample collection and a Varian Saturn 2000 ion trap mass spectrome...

410

LONG-TERM STUDY OF VOLATILE ORGANIC COMPOUND RECOVERY FROM AMPULATED, DRY, FORTIFIED SOILS  

EPA Science Inventory

Our objective was to evaluate the stability and extractability of volatile organic compound (VOCs) when fortified on dry soils and stored in sealed ampules. Two desiccator-dried soils were fortified with eight neat VOCs, benzene,toluene,ethylbenzene,o-xylene,1,1,1-trichloroethane...

411

A method for measuring semi- and non-volatile organic halogens by combustion ion chromatography  

Microsoft Academic Search

Recent studies have shown that various semi- and non-volatile organohalogen compounds are ubiquitous in the environment: these include halogenated dioxins including chlorinated dioxins, other persistent organic pollutants (POPs), brominated flame retardants (BFRs), and perfluorooctane sulfonate (PFOS). However, monitoring and assessment of these compounds by the analyses of individual compounds and their isomers is onerous because of their low environmental concentrations

Yuichi Miyake; Mika Kato; Kohei Urano

2007-01-01

412

The role of boundary layers in the removal of volatile organic compounds from water by pervaporation  

Microsoft Academic Search

Removal of volatile organic compounds (VOCs) from water by pervaporation is dominated by boundary layer effects (concentration polarization). A simple analysis shows these effects to be much more severe in pervaporation than in ultrafiltration and reverse osmosis because of the high VOC enrichment that can be obtained by pervaporation. In pervaporation, the concentration of solute at the membrane surface is

J. G. Wijmans; A. L. Athayde; R. Daniels; J. H. Ly; H. D. Kamaruddin; I. Pinnau

1996-01-01

413

Volatile Organic Metabolites Identify Patients with Breast Cancer, Cyclomastopathy, and Mammary Gland Fibroma  

PubMed Central

The association between cancer and volatile organic metabolites in exhaled breaths has attracted increasing attention from researchers. The present study reports on a systematic study of gas profiles of metabolites in human exhaled breath by pattern recognition methods. Exhaled breath was collected from 85 patients with histologically confirmed breast disease (including 39 individuals with infiltrating ductal carcinoma, 25 individuals with cyclomastopathy and from 21 individuals with mammary gland fibroma) and 45 healthy volunteers. Principal component analysis and partial least squares discriminant analysis were used to process the final data. The volatile organic metabolites exhibited significant differences between breast cancer and normal controls, breast cancer and cyclomastopathy, and breast cancer and mammary gland fibroma; 21, 6, and 8 characteristic metabolites played decisive roles in sample classification, respectively (P < 0.05). Three volatile organic metabolites in the exhaled air, 2,5,6-trimethyloctane, 1,4-dimethoxy-2,3-butanediol, and cyclohexanone, distinguished breast cancer patients from healthy individuals, mammary gland fibroma patients, and patients with cyclomastopathy (P < 0.05). The identified three volatile organic metabolites associated with breast cancer may serve as novel diagnostic biomarkers.

Wang, Changsong; Sun, Bo; Guo, Lei; Wang, Xiaoyang; Ke, Chaofu; Liu, Shanshan; Zhao, Wei; Luo, Suqi; Guo, Zhigang; Zhang, Yang; Xu, Guowang; Li, Enyou

2014-01-01

414

OPTIMIZATION OF MULTICOMPONENT PERVAPORATION FOR REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM WATER  

EPA Science Inventory

Optimal operation of a hollow fiber membrane module for pervaporative removal of multicomponent volatile organic compounds (VOCs) from wastewater was studied. A shell-and-tube heat-exchange type of hollow fiber module was considered for treatment of a wastewater containing toluen...

415

OPTIMIZATION OF MULTICOMPONENT PERVAPORATION FOR REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM WATER  

EPA Science Inventory

Optimal operation of a hollow fiber membrane module for pervaporative removal of multicomponent volatile organic compounds (VOCS) from wastewater was studied. hell-and-tube heat-exchanger type of hollow fiber module was considered for treatment of a wastewater containing toluene,...

416

Portable acoustic wave sensor systems for real-time monitoring of volatile organic compounds  

Microsoft Academic Search

Portable acoustic wave sensor (PAWS) systems are being developed for real-time, on-line and in situ monitoring of volatile organic compounds (VOCs). These systems are built around surface acoustic wave (SAW) devices coated with viscoelastic polymers. Two independent responses of the SAW sensor, wave velocity and attenuation, are measured to provide information about the chemical species sorbed by the coating. Sensing

R. W. Cernosek; G. C. Frye; D. W. Gilbert

1993-01-01

417

Impact of regulation on indoor volatile organic compounds in new unoccupied apartment in Korea  

Microsoft Academic Search

The Indoor Air Quality (IAQ) Control in Public Use Facilities Act in Korea, which came into effect on January 1, 2006, set standards of indoor environmental concentrations for benzene, toluene, ethylbenzene, xylenes, styrene, and formaldehyde. This study aimed to determine the impact of the Act on levels of volatile organic compounds (VOCs) and to identify factors associated with indoor VOCs

Soogil Lim; Kiyoung Lee; Sooyun Seo; Seongki Jang

2011-01-01

418

Reduction of volatile organic compound emissions from the application of traffic markings. Final report  

Microsoft Academic Search

Traditional traffic marking materials (solvent-borne paints) are a source of volatile organic compound (VOC) emissions. The study was conducted to evaluate alternative traffic-marking techniques that can be used to reduce VOC emissions from this source. This document provides information on traffic marking application processes, VOC emissions and emission reductions, and costs associated with the alternative marking techniques. The primary conclusions

G. A. Aurand; M. B. Turner; C. J. Athey; R. M. Neulicht

1988-01-01

419

Volatile organic compounds in industrial, urban, and suburban areas: Sources and exposures  

Microsoft Academic Search

This research was aimed at evaluating and refining sampling and analytical methods for airborne volatile organic compounds (VOCs), and at characterizing concentrations and potential exposures of VOCs found in indoor and ambient air in industrial, urban and suburban communities. A new analytical strategy of combining selective ion monitoring (SIM) and scan mode mass spectrometer analyses was developed and evaluated. This

Chunrong Jia

2007-01-01

420

EMISSION OF VOLATILE ORGANIC COMPOUNDS FROM DRUM-MIX ASPHALT PLANTS  

EPA Science Inventory

This research program was undertaken in order to develop a quantitative estimate of the emission of volatile organic compounds (VOCs) from drum-mix asphalt plants. The study was carried out by field sampling of five drum-mix plants under a variety of operating conditions. Include...

421

Intercomparison of oxygenated volatile organic compound measurements at the SAPHIR atmosphere simulation chamber  

Microsoft Academic Search

This paper presents results from the first large-scale in situ intercomparison of oxygenated volatile organic compound (OVOC) measurements. The intercomparison was conducted blind at the large (270 m3) simulation chamber, Simulation of Atmospheric Photochemistry in a Large Reaction Chamber (SAPHIR), in Jülich, Germany. Fifteen analytical instruments, representing a wide range of techniques, were challenged with measuring atmospherically relevant OVOC species

E. C. Apel; T. Brauers; R. Koppmann; B. Bandowe; J. Boßmeyer; C. Holzke; R. Tillmann; A. Wahner; R. Wegener; A. Brunner; M. Jocher; T. Ruuskanen; C. Spirig; D. Steigner; R. Steinbrecher; E. Gomez Alvarez; K. Müller; J. P. Burrows; G. Schade; S. J. Solomon; A. Ladstätter-Weißenmayer; P. Simmonds; D. Young; J. R. Hopkins; A. C. Lewis; G. Legreid; S. Reimann; A. Hansel; A. Wisthaler; R. S. Blake; A. M. Ellis; P. S. Monks; K. P. Wyche

2008-01-01

422

Scale-up analysis and development of gliding arc discharge facility for volatile organic compounds decomposition  

Microsoft Academic Search

The influences of inlet gas flow rate and reactor configuration on volatile organic compounds (VOCs) decomposition efficiency in a traditional gliding arc (T-GA) facility are studied based on laboratory experiments and numerical simulation. The ratio of the nozzle diameter and the shortest distance of two electrodes should be maintained in a suitable value range to guarantee the decomposition efficiency, which

Zheng Bo; Jianhua Yan; Xiaodong Li; Yong Chi; Kefa Cen

2008-01-01

423

Emissions of volatile organic compounds during the decomposition of plant litter  

Microsoft Academic Search

Volatile organic compounds (VOCs) are emitted during plant litter decomposition, and such VOCs can have wide-ranging impacts on atmospheric chemistry, terrestrial biogeochemistry, and soil ecology. However, we currently have a limited understanding of the relative importance of biotic versus abiotic sources of these VOCs and whether distinct types of litter emit different types and quantities of VOCs during decomposition. We

Christopher M. Gray; Russell K. Monson; Noah Fierer

2010-01-01

424

Treatment of Volatile Organic Compound by Positive Streamer Corona Using a Series Gap  

Microsoft Academic Search

The nonthermal atmospheric pressure plasma produced by streamer corona discharge was used for the treatment of volatile organic compounds (VOCs). The decomposition rate of toluene as a VOC was investigated under various discharge conditions of discharge period, pulse rise time of discharge voltage and gas flow rate. The quantity of byproducts due to the toluene decomposition was controlled by the

Nobuya Hayashi; Hideo Suganuma; Masaki Kamatani; Saburoh Satoh; Chobei Yamabe

2001-01-01

425

Application of Electron Beams, Microwaves and Catalysis to Volatile Organic Compounds Decomposition  

Microsoft Academic Search

A hybrid technique, developed for volatile organic compounds (VOCs) decomposition using electron beam (EB) irradiation, microwave (MW) treatment, and catalyst method, is presented. The combination of a non-thermal plasma (NTP) induced by both, EB and MW, with in situ heterogeneous catalysis (denoted as ``EB+MW plasma catalysis'') is presented as a new approach and a promising method to improve the oxidation

Daniel I. Ighigeanu; Ioan I. Calinescu; Diana I. Martin; Constantin I. Matei

2007-01-01

426

Electron beam and pulsed corona processing of volatile organic compounds and nitrogen oxides  

Microsoft Academic Search

Electrical discharge reactors are most suitable for processes requiring O radicals. For processes requiring copious amounts of electrons or N atoms, the use of electron beam reactors is generally the best way of minimizing the electrical energy consumption. For many of the volatile organic compounds (VOCs) the authors have investigated, they found that electron beam processing is more energy efficient

B. M. Penetrante; M. C. Hsiao; J. N. Bardsley; B. T. Merritt; G. E. Vogtlin; P. H. Wallman; A. Kuthi; C. P. Burkhart; J. R. Bayless

1995-01-01

427

Cadaveric volatile organic compounds released by decaying pig carcasses ( Sus domesticus L.) in different biotopes  

Microsoft Academic Search

Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate the entomofaunal colonization. Insects communicate with their environment through the use of chemical mediators, which in the case of necrophagous insects, may consist in the cadaveric volatile organic compounds (VOCs) released by the corpse under decomposition. Previous studies have focused on cadaveric VOCs released from human corpses. Nevertheless,

J. Dekeirsschieter; F. J. Verheggen; M. Gohy; F. Hubrecht; L. Bourguignon; G. Lognay; E. Haubruge

2009-01-01

428

Nitrogen dioxide formation in the gliding arc discharge-assisted decomposition of volatile organic compounds  

Microsoft Academic Search

To apply gliding arc discharge (GAD) plasma processing to volatile organic compounds (VOCs) emission control, the formation of NO2 as an undesired byproduct needs to be addressed. Comparative results of effluent temperature and product concentrations between experiment and thermodynamic equilibrium calculation show that the NO2 formation in dry air GAD is totally out of thermodynamic equilibrium. Meanwhile, obvious NO (A2?+)

Zheng Bo; Jianhua Yan; Xiaodong Li; Yong Chi; Kefa Cen

2009-01-01

429

DETERMINATION OF POLAR VOLATILE ORGANIC COMPOUNDS IN WATER BY MEMBRANE PERMEATE AND TRAP GC-MS  

EPA Science Inventory

A novel approach is presented combining semipermeable membranes with the accepted purge and trap gas chromatography-mass spectrometry (GC-MS) technology to produce a method of selectively extracting polar, volatile organic compounds from water, particularly those compounds not am...

430

Survey of bottled drinking water sold in Canada. Part 2. Selected volatile organic compounds  

Microsoft Academic Search

Selected volatile organic compound (VOC) contaminants were determined in 182 samples of retail bottled waters purchased in Canada. Samples included spring water (86) packaged in containers of polyethylene or in smaller containers of transparent plastic or glass, mineral water (61) packaged only in transparent plastic or glass, and miscellaneous bottled waters (35). Analyses were performed by 3 laboratories, each using

B. D. Page; H. B. S. Conacher; J. Salminen

1993-01-01

431

A study on volatile organic sulfide causes of odors at Philadelphia's Northeast Water Pollution Control Plant  

Microsoft Academic Search

Volatile organic sulfide (VOS) causes of odors were studied at Philadelphia's Northeast Water Pollution Control Plant between September 11 and November 25, 2003. Results showed that dimethyl sulfide (DMS) dominated the VOS pool whenever VOS concentration rose above the background level (<50?g\\/L). Methanethiol was generally less than 10% of VOS and it was mainly found at sites with limited or

Xianhao Cheng; Earl Peterkin; Gary A. Burlingame

2005-01-01

432

EPA ORD VOLATILE ORGANIC COMPOUNDS RECOVERY SEMINAR, OVERVIEW AND CONCLUDING REMARKS  

EPA Science Inventory

The USEPA conducted a seminar during 9/98 in Cincinnati, OH which focused on recovering Volatile Organic Compounds (VOCs). The seminar emphasized new/innovative VOC Recovery technologies as well as commercially available technologies and addressed applications in all environmenta...

433

HISTORIC EMISSIONS OF VOLATILE ORGANIC COMPOUNDS IN THE UNITED STATES FROM 1900 TO 1985  

EPA Science Inventory

The report gives an estimate of historic emissions of volatile organic compounds (VOCs) for each state (and the District of Columbia) of the contiguous U.S. Annual emissions were estimated on the national level from 1960 to 1985. For 1940, 1950, and every fifth year from 1960 to ...

434

EVALUATION OF THE FLUX CHAMBER METHOD FOR MEASURING VOLATILE ORGANIC EMISSIONS FROM SURFACE IMPOUNDMENTS  

EPA Science Inventory

This research deals with the validation of the flux chamber method for measuring volatile organic emissions from liquid surfaces in treatment, storage and disposal facilities (TSDF). A simulated surface impoundment was constructed so that method precision and accuracy could be de...

435

Housing Characteristics and Indoor Concentrations of Selected Volatile Organic Compounds (VOCs) in Quebec City, Canada  

Microsoft Academic Search

Concentrations of 26 volatile organic compounds (VOCs) were measured continuously for 7 days during winter in 96 homes in Quebec City, Canada. Characteristics of the houses and activities of the occupants were documented through detailed questionnaires filled out by one adult per household. VOCs were sampled using passive monitors and analyzed by gas chromatography-mass selective detector (GC-MSD). Results indicate contributions

Marie-Ève Héroux; Denis Gauvin; Nicolas L. Gilbert; Mireille Guay; Geneviève Dupuis; Michel Legris; Benoît Lévesque

2008-01-01

436

Volatile organic compound concentrations in ambient air of Kaohsiung petroleum refinery in Taiwan  

Microsoft Academic Search

The air quality assessment for volatile organic compounds (VOC) was conducted in and around Chinese petroleum corporation (CPC) refinery at Kaohsiung, located in southern Taiwan, during 2001 by collecting air samples at 26 sites. Benzene and toluene were detected as the most abundant VOC by both gas chromatography and ultra-violet differential optical absorption spectroscopy (UV-DOAS) techniques. BTXE concentrations showed day

Tsai-Yin Lin; Usha Sree; Sen-Hong Tseng; Kong Hwa Chiu; Chien-Hou Wu; Jiunn-Guang Lo

2004-01-01

437

EVALUATION OF CONTROL STRATEGIES FOR VOLATILE ORGANIC COMPOUND IN INDOOR AIR  

EPA Science Inventory

The Air and Energy Engineering Research Laboratory of the U.S. Environmental Protection Agency (U.S. EPA) conducts and sponsors research on technology to reduce or eliminate emissions of potentially toxic volatile organic compounds (VOCs) from industrial/commercial sources. The r...

438

Reactions of Volatile Furandiones, Aldehydes and Water Vapor in Secondary Organic Aerosol Formation and in Gas Chromatography Analysis  

NASA Astrophysics Data System (ADS)

Volatile furandiones and aldehydes are important atmospheric oxidation products of simple aromatic compounds found in gasoline. A mechanism of secondary organic aerosol formation by furandiones was identified using particle chamber observations and FTIR measurements of model condensed phases. Growth of inorganic seed aerosol was monitored by scanning mobility particle sizing in the presence of humidity and high concentrations of 2,5-furandione (maleic anhydride), 3-methyl-2,5-furandione (citraconic anhydride), benzaldehyde, and trans-cinnamaldehyde. Particle growth began when the gas-phase saturation level of each organic compound (relative to its pure liquid) and water vapor, when summed together, reached a threshold near one. This threshold implies that equilibrium is established between the gas phase and a newly formed, mixed condensed phase containing both organic compounds and water. This equilibrium appears to be governed by Raoult's Law, where the vapor pressure of each component is reduced proportionally to its mole fraction in the condensed phase. However, bulk liquid phase experiments showed that these organics are immiscible with water at the mole fractions expected in the particle phase in our chamber experiments. Thus, non-reactive condensation of these compounds into a mixed organic / aqueous phase is ruled out. Instead, we show that reactions between furandiones and water produce unusually strong dicarboxylic acids: cis-methylbutenedioic acid (citraconic acid) and cis-butenedioic acid (maleic acid). Bulk phase pH microprobe and FTIR attenuated total reflectance measurements demonstrated that an aqueous phase is rapidly acidified during exposure to furandiones. In addition, the presence of furandiones also greatly increased benzaldehyde solubility. This solubility increase has two causes. First, the entry of maleate (or methylmaleate) ions into the water layer lowers the polarity of the phase. Second, the increase in acidity may enhance reactivity at the aldehyde functional group. Thus the uptake of both furandiones and aldehydes onto particles in the presence of humidity appears to be reaction-dependent. When subjected to normal GC injector temperatures, the cis-butenedioic acids produced in these reactions recyclize back to furandiones with much greater ease than similar alkanedioic or trans-alkenedioic acids. This production of volatile compounds during GC analysis could cause large artifacts in gas / particle phase distribution measurements if chemical derivatization techniques are not employed.

Koehler, C. A.; Fillo, J. D.; Ries, K. A.; Sanchez, J. T.; de Haan, D. O.

2004-05-01

439

Investigation of sources of volatile organic carbon in the Baltimore area using highly time-resolved measurements  

Microsoft Academic Search

A multivariate receptor model, UNMIX, was applied to hourly volatile organic hydrocarbon concentrations measured at a Photochemical Assessment Monitoring Station, located in the Baltimore, MD area, during the summer months from 1996 to 1999. Six possible volatile organic carbon source categories were identified, and gasoline-related sources such as vehicle exhaust, gasoline vapor, and liquid gasoline contributed more than half of

Yu-Jin Choi; Sheryl H Ehrman

2004-01-01

440

(Semi)volatile Organic Compounds and Microbiological Entities in Snow during OASIS Barrow 2009  

NASA Astrophysics Data System (ADS)

Snow has recently been shown to be an active medium for the deposition of (semi-)volatile (bio)organic compounds. We collected surface snow samples during the OASIS Barrow campaign in March 2009 for analysis of semi-volatile organic compounds using solid phase microextraction and gas chromatography with mass spectrometric detection (SPME-GC/MS). Additional grab samples were taken for analysis of non-methane hydrocarbons in air. Moreover we analyzed for microbial species in air and snow. Identifed organic compounds covered a wide range of functionalities and molecular weights, including oxygenated reactive speces such as aldehydes (e.g., hexanal to decanal), alcohols (e.g., hexanol, octanol) and aromatic species (e.g., methyl- and ethylbenzenes). Quantification data for selected aromatic species are presented with concentrations in the upper ng/L range. We will present our preliminary data on microbiological species, and will discuss the potential implications of the results for organic snow chemistry.

Kos, G.; Nafissa, A.; Lutchman, D.; Mortazavi, R.; Ariya, P.

2009-12-01

441

Identification and characterization of bacteria isolated under selective pressure of volatile organic compounds.  

PubMed

Several bacterial strains tolerant to volatile organic compounds (VOCs) were isolated from the air emissions of a typical industrial wood painting plant. Four strains that grew vigorously on a mineral salt basal medium and VOC-saturated atmosphere were identified using BIOLOG and fatty acids analysis. A 16S rDNA sequence comparison was also performed on three of the four strains. Their phylogenetic positions were respectively: MC8M6 of the genus Arthrobacter MCEP3 of the genus Microbacterium, MCEPFL2 of the genus Rhodococcus. The fourth strain, C14, was identified as Pseudomonas aeruginosa. All the four strains showed multiple carbon sources among toluene, butyl acetate, ethoxy propyl acetate, isobutyl alcohol, ethyl acetate, diaceton alcohol, methyl ethyl ketone, methyl isobutyl ketone. By identifying a particular strain, an evaluation of its risk group can be made by comparing it to each strain type within important world-wide culture collections. This is the first step required to implement correct procedures using the strains and in implementing the appropriate biosafety containment in large scale applications. PMID:20112870

Civilini, Marcello

2009-01-01

442

Testing the optimal defence hypothesis for two indirect defences: extrafloral nectar and volatile organic compounds  

PubMed Central

Many plants respond to herbivory with an increased production of extrafloral nectar (EFN) and/or volatile organic compounds (VOCs) to attract predatory arthropods as an indirect defensive strategy. In this study, we tested whether these two indirect defences fit the optimal defence hypothesis (ODH), which predicts the within-plant allocation of anti-herbivore defences according to trade-offs between growth and defence. Using jasmonic acid-induced plants of Phaseolus lunatus and Ricinus communis, we tested whether the within-plant distribution pattern of these two indirect defences reflects the fitness value of the respective plant parts. Furthermore, we quantified photosynthetic rates and followed the within-plant transport of assimilates with 13C labelling experiments. EFN secretion and VOC emission were highest in younger leaves. Moreover, the photosynthetic rate increased with leaf age, and pulse-labelling experiments suggested transport of carbon to younger leaves. Our results demonstrate that the ODH can explain the within-plant allocation pattern of both indirect defences studied.

Radhika, Venkatesan; Kost, Christian; Bartram, Stefan; Heil, Martin

2008-01-01

443

Combustion of volatile organic compounds over composite catalyst of Pt/?-Al?O? and beta zeolite.  

PubMed

Catalytic oxidation of volatile organic compounds (VOCs) was carried out over a composite catalyst comprising Pt/?-Al?O? and protonated beta zeolite. The conversion of several VOCs such as ethyl acetate, butyl acetate, 2-propanol, 1,2-dichloroethane, and chloroethane over the composite catalyst was higher than the conversion over the conventional Pt/?-Al?O? catalyst, indicating a remarkable improvement in the oxidation activity of the composite. On the other hand, no difference in the conversion of methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and chloroethylene was observed for the composite catalyst versus the Pt/?-Al?O? catalyst. To clarify the role of the zeolite component, the reaction products obtained using the composite catalyst were compared with those obtained using the Pt/?-Al?O? catalyst. For the cases in which considerable improvement in the oxidation activity was observed with the composite, it was revealed that the conversion of VOCs to intermediate compounds took place over the acidic sites of the zeolite; the intermediates tended to be easily oxidized to CO? on the Pt/?-Al?O? catalyst. In addition, the composite catalyst also exhibited high durability. High catalytic activity was maintained even after aging at 600°C for more than 1000 h. PMID:23445410

Takamitsu, Yasuyuki; Yoshida, Satoshi; Kobayashi, Wataru; Ogawa, Hiroshi; Sano, Tsuneji

2013-01-01

444

Volatile organic compound emissions from elephant grass and bamboo cultivars used as potential bioethanol crop  

NASA Astrophysics Data System (ADS)

Volatile organic compound (VOC) emissions from elephant grass (Miscanthus gigantus) and black bamboo (Phyllostachys nigra) were measured online in semi-field chamber and plant enclosure experiments during growth and harvest using proton-transfer reaction mass spectrometry (PTR-MS), proton-transfer reaction ion-trap mass spectrometry (PIT-MS) and gas chromatography-mass spectrometry (GC-MS). Both cultivars are being considered for second-generation biofuel production. Before this study, no information was available on their yearly VOC emissions. This exploratory investigation shows that black bamboo is a strong isoprene emitter (daytime 28,516 ng gdwt-1 h-1) and has larger VOC emissions, especially for wound compounds from the hexanal and hexenal families, than elephant grass. Daytime emissions of methanol, acetaldehyde, acetone + propanal and acetic acid of black bamboo were 618, 249, 351, and 1034 ng gdwt-1 h-1, respectively. In addition, it is observed that elephant grass VOC emissions after harvesting strongly depend on the seasonal stage. Not taking VOC emission variations throughout the season for annual and perennial species into account, may lead to an overestimation of the impact on local air quality in dry periods. In addition, our data suggest that the use of perennial grasses for extensive growing for biofuel production have lower emissions than woody species, which might be important for regional atmospheric chemistry.

Crespo, E.; Graus, M.; Gilman, J. B.; Lerner, B. M.; Fall, R.; Harren, F. J. M.; Warneke, C.

2013-02-01

445

Volatile organic carbon emissions. Phase 2. Final report, April 1985-December 1986  

SciTech Connect

Engineering studies evaluated bisulfite (HS0/sub 3/) absorbent solutions in a bench-scale absorption unit for the control of volatile organic compounds (VOCs) emitted from the manufacture of multi-base propellent at Radford Army Ammunition Plant. An optimization study showed that a dual-column absorption system is required for the removal of solvent vapors: a recycle column containing 15 wt% (HS0/sub 3/) absorbent solution and a single-pass column using plant-process water. The recycle column concentrated acetone to 1.6 wt% in the absorber bottoms, resulting in 40-85% solvent recovery by distillation; the single-pass column failed to concentrate ethanol sufficiently for recovery. The 15 wt % HS0/sub 3/ absorbent solution also destroyed both neat and vaporous nitroglycerin. Economic analyses of the proposed process designs for the multi-base propellant mixing process and forced air drying operations indicated HSO/sub 3/ absorbent systems to be uneconomical. Therefore, alternative VOC abatement systems were cursorily evaluated, including glycols and sulfuric acid as absorbents, membrane technology, Ceilcote's VOC control system, and Union Carbide's PURASIV HR solvent recovery process.

Jake, C.A.

1987-02-01

446

Volatile organic solvents in correction fluids: Identification and potential hazards  

Microsoft Academic Search

Exposure to organic solvents is widespread in today's environment. The extent of exposure differs, high concentration exposure is being often experienced by workers in uncontrolled factories. Exposure in schools, however, was not an area of concern until recently when glue sniffing was reported to be practiced by children of school going age. The common solvents encountered in schools include paint

C. N. Ong; D. Koh; S. C. Foo; P. W. Kok; H. Y. Ong; T. C. Aw

1993-01-01

447

Soluble phthalocyanines as coatings for quartz-microbalances: specific and unspecific sorption of volatile organic compounds  

Microsoft Academic Search

Various new phthalocyanines (PcMs) species were synthesized which can be dissolved in organic solvents. They turned out to form particularly sensitive coatings on quartz-microbalances (QMBs) for the detection of a variety of volatile organic compounds (VOCs) in the gas phase. A two-step sorption model describes both, the initial highly sensitive response at low concentrations by preferential absorption and the less

C. Fietzek; K. Bodenhöfer; P. Haisch; M. Hees; M. Hanack; S. Steinbrecher; F. Zhou; E. Plies; W. Göpel

1999-01-01

448

Effectiveness of purge-and-trap for measurement of volatile organic compounds in aged soils  

Microsoft Academic Search

The U.S. EPA-recommended method for measurement of trace levels of volatile organic compounds (VOCs) in soil, purge-and-trap, measures the readily desorbable organic contaminants from soil pore spaces and external soil surfaces. It does not, however, measure contamination that has diffused into internal micropores of soil matrix. Thus, the purge-and-trap method measures only a small fraction of total soil contaminants, especially

Minoo D. F. Askari; Michael P. Maskarinec; Stacy M. Smith; C. C. Travis; P. M. Beam

1996-01-01

449

The activity and mechanism of uranium oxide catalysts for the oxidative destruction of volatile organic compounds  

Microsoft Academic Search

Uranium oxide based catalysts have been investigated for the oxidative destruction of volatile organic compounds (VOCs) to carbon oxides and water. The catalysts have been tested for the destruction of a range of organic compounds at space velocities up to 70000h?1. Destruction efficiencies greater than 99% can be achieved over the appropriate uranium based catalyst in the temperature range 300–450°C.

Stuart H Taylor; Catherine S Heneghan; Graham J Hutchings; Ian D Hudson

2000-01-01

450

Determination of Volatile Organic Compounds in Indoor Air of Buildings in Nuclear Power Plants, Taiwan  

Microsoft Academic Search

This study investigates the composition and concentrations of volatile organic compounds (VOCs) in air-conditioned office\\u000a space and low-level waste (LLW) repository sites of nuclear power plants located in Taiwan. Air samples were collected in\\u000a the office space and technical rooms of administration buildings of the three nuclear power plants and in LLW repository site\\u000a using canisters. Thirty-six toxic organic compounds

Ling-Ling Hsieh; Chih-Chung Chang; Usha Sree; Jiunn-Guang Lo

2006-01-01

451

Adsorption of volatile organic compounds by metal–organic frameworks MIL101: Influence of molecular size and shape  

Microsoft Academic Search

Adsorption of gaseous volatile organic compounds (VOCs) on metal–organic frameworks MIL-101, a novel porous adsorbent with extremely large Langmuir surface area of 5870m2\\/g and pore volume of 1.85cm3\\/g, and the influence of VOC molecular size and shape on adsorption were investigated in this study. We observed that MIL-101 is a potential superior adsorbent for the sorptive removal of VOCs including

Kun Yang; Qian Sun; Feng Xue; Daohui Lin

2011-01-01

452

Characterisation of calamansi (Citrus microcarpa). Part I: volatiles, aromatic profiles and phenolic acids in the peel.  

PubMed

Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent oxygenated compounds was significantly different, exemplified by the highest amount of methyl N-methylanthranilate in Malaysian calamansi peel. Principal component analysis and canonical discriminant analysis were applied to interpret the complex volatile compounds in the calamansi peel extracts, and to verify the discrimination among the different origins. In addition, four common hydroxycinnamic acids (caffeic, p-coumaric, ferulic and sinapic acids) were determined in the methanolic extracts of calamansi peel using ultra-fast liquid chromatography coupled to photodiode array detector. The Philippines calamansi peel contained the highest amount of total phenolic acids. In addition, p-Coumaric acid was the dominant free phenolic acids, whereas ferulic acid was the main bound phenolic acid. PMID:23107679

Cheong, Mun Wai; Chong, Zhi Soon; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Bin Yu

2012-09-15

453

The effect of fumaric acid and sodium fumarate supplementation to diets for weanling pigs on amino acid digestibility and volatile fatty acid concentrations in ileal digesta  

Microsoft Academic Search

An experiment was carried out with 12 Camborough × Canabrid barrows to determine the effect of fumaric acid (FA) and sodium fumarate (NaFA) supplementation of the diet on the apparent ileal digestibility coefficients of amino acids and the concentrations of volatile fatty acids in ileal digesta. The pigs were weaned at 28 days of age (initial and final body weights

V. M. Gabert; W. C. Sauer

1995-01-01

454

CORRELATION BETWEEN RUMINAL pH AND SHORT CHAIN VOLATILE FATTY ACID IN DAIRY COWS  

Microsoft Academic Search

SUMMARY Subacute rumen acidosis (SARA) represents one of the most common disorder in the intensive dairy farms that affects ruminal fermentations, animal health, productivity and farm profitability. The aim of the present study was to determine the short chain volatile fatty acids (SCVFA) and pH in ruminal fluid of lactating dairy cows. Five commercial dairy herds suspected of SARA were

455

A biochemical model describing volatile fatty acid metabolism in thermophilic aerobic digestion of wastewater sludge  

Microsoft Academic Search

A biochemical model was developed to explain the mechanism of volatile fatty acid (VFA) metabolism in Thermophilic Aerobic Digestion (TAD). The effects of substrate addition on the metabolic behavioral patterns of TAD biomass, from a pilot scale system, were examined. The majority of the substrates examined under batch test conditions, with TAD process biomass, under microaerobic conditions, were oxidized to

A. Chu; D. S. Mavinic; W. D. Ramey; H. G. Kelly

1996-01-01

456

Characteristics of Volatile Fatty Acid and Oxidation Reduction Potential for Treating Municipal Wastewater in Modified EGSB  

Microsoft Academic Search

The traditional Expanded Granular Sludge Bed (EGSB) reactor was modified to treating municipal wastewater. The characteristics of Oxidation Reduction Potential (ORP) and Volatile Fatty Acid (VFA) concentration of effluent was studied to judge to the operation condition of anaerobic degradation process. The characteristics of ORP and VFA for treating municipal wastewater was studied in modified Expanded Granular Sludge Bed (EGSB).

Ma Limin; Sun Xiaojing; Ma Xiujuan

2009-01-01