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Sample records for polar volatile organic

  1. Volatile organic compounds

    International Nuclear Information System (INIS)

    Silseth, May Liss

    1998-01-01

    The goal is: Not more emission of volatile organic compounds (VOCs) than necessary. The items discussed in this presentation are the VOCs, how to calculate emission of VOCs, how to reduce or avoid them, and different recovery processes. The largest source of Norwegian emissions of non methane VOCs (NMVOCs) is offshore loading of raw petroleum. Emissions of VOCs should be reduced mainly for two reasons: (1) on sunny days NMVOCs may react with NOx to form ozon and smog close to the surface, (2) ozone and smog close to the surface may be harmful to plants and animals, and they are hazardous to human health. As for the calculation of VOC emissions, the VOCON project will release the calculation program HCGASS in 1999. This project is a cooperative project headed by SINTEF/Marintek

  2. Simultaneous quantification of polar and non-polar volatile organic compounds in water samples by direct aqueous injection-gas chromatography/mass spectrometry.

    Science.gov (United States)

    Aeppli, Christoph; Berg, Michael; Hofstetter, Thomas B; Kipfer, Rolf; Schwarzenbach, René P

    2008-02-15

    A direct aqueous injection-gas chromatography/mass spectrometry (DAI-GC/MS) method for trace analysis of 24 volatile organic compounds (VOCs) in water samples is presented. The method allows for the simultaneous quantification of benzene, toluene, ethyl benzene, and xylenes (BTEX), methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA), as well as a variety of chlorinated methanes, ethanes, propane, enthenes and benzenes. Applying a liquid film polyethylene glycol or a porous layer open tubular (PLOT) divinylbenzene GC capillary column to separate the water from the VOCs, volumes of 1-10 microL aqueous sample are directly injected into the GC. No enrichment or pretreatment steps are required and sample volumes as low as 100 microL are sufficient for accurate quantification. Method detection limits determined in natural groundwater samples were between 0.07 and 2.8 microg/L and instrument detection limits of VOCs. DAI-GC/MS offers both good accuracy and precision (relative standard deviations VOC concentration measurements in a polluted aquifer. The wide range of detectable compounds and the lack of labor-intensive sample preparation illustrate that the DAI method is robust and easily applicable for the quantification of important organic groundwater contaminants.

  3. potential bag filter for volatile organic amines

    Indian Academy of Sciences (India)

    VADDYPALLY SHIVAIAH

    2018-03-22

    Mar 22, 2018 ... be described as a potential bag filter for volatile organic amines. Keywords. Volatile organic amines; hydrogen ..... this bag filter, which can capture volatile amines to form. Figure 8. Thermal ellipsoid plot of ..... huber H, Baumann M and Amann A 2013 Blood and breath levels of selected volatile organic ...

  4. Organic non-volatile memories from ferroelectric phase-separated blends

    NARCIS (Netherlands)

    Asadi, Kamal; De Leeuw, Dago M.; De Boer, Bert; Blom, Paul W. M.

    New non-volatile memories are being investigated to keep up with the organic-electronics road map(1). Ferroelectric polarization is an attractive physical property as the mechanism for non-volatile switching, because the two polarizations can be used as two binary levels(2). However, in

  5. Factors affecting the volatilization of volatile organic compounds from wastewater

    Directory of Open Access Journals (Sweden)

    Junya Intamanee

    2006-09-01

    Full Text Available This study aimed to understand the influence of the wind speed (U10cm, water depth (h and suspended solids (SS on mass transfer coefficient (KOLa of volatile organic compounds (VOCs volatilized from wastewater. The novelty of this work is not the method used to determine KOLa but rather the use of actual wastewater instead of pure water as previously reported. The influence of U10cm, h, and SS on KOLa was performed using a volatilization tank with the volume of 100-350 L. Methyl Ethyl Ketone (MEK was selected as a representative of VOCs investigated here in. The results revealed that the relationship between KOLa and the wind speeds falls into two regimes with a break at the wind speed of 2.4 m/s. At U10cm 2.4 m/s, KOLa increased more rapidly. The relationship between KOLa and U10cm was also linear but has a distinctly higher slope. For the KOLa dependency on water depth, the KOLa decreased significantly with increasing water depth up to a certain water depth after that the increase in water depth had small effect on KOLa. The suspended solids in wastewater also played an important role on KOLa. Increased SS resulted in a significant reduction of KOLa over the investigated range of SS. Finally, the comparison between KOLa obtained from wastewater and that of pure water revealed that KOLa from wastewater were much lower than that of pure water which was pronounced at high wind speed and at small water depth. This was due the presence of organic mass in wastewater which provided a barrier to mass transfer and reduced the degree of turbulence in the water body resulting in low volatilization rate and thus KOLa. From these results, the mass transfer model for predicting VOCs emission from wastewater should be developed based on the volatilization of VOCs from wastewater rather than that from pure water.

  6. Method for analysis of polar volatile trace components in aqueous samples by gas chromatography.

    Science.gov (United States)

    Pettersson, Johan; Roeraade, Johan

    2005-05-15

    A new method has been developed for direct analysis of volatile polar trace compounds in aqueous samples by gas chromatography. Water samples are injected onto a short packed precolumn containing anhydrous lithium chloride. A capillary column is coupled in series with the prefractionation column for final separation of the analytes. The enrichment principle of the salt precolumn is reverse to the principles employed in conventional methods such as SPE or SPME in which a sorbent or adsorbent is utilized to trap or concentrate the analytes. Such methods are not efficient for highly polar compounds. In the LiCl precolumn concept, the water matrix is strongly retained on the hygroscopic salt, whereas polar as well as nonpolar volatile organic compounds show very low retention and are eluted ahead of the water. After transfer of the analytes to the capillary column, the retained bulk water is removed by backflushing the precolumn at elevated temperature. For direct injections of 120 microL of aqueous samples, the combined time for injection and preseparation is only 3.5 min. With this procedure, direct repetitive automated analyses of highly volatile polar compounds such as methanol or tetrahydrofuran can be performed, and a limit of quantification in the low parts-per-billion region utilizing a flame ionization detector is demonstrated.

  7. Characterisation of selected volatile organic compounds in ...

    African Journals Online (AJOL)

    kshale

    2013-05-15

    May 15, 2013 ... compounds play an important role as they provide relative information on the product quality and enhance product ... beer samples were collected from a local market in Kigali, Rwanda; and were analyzed for volatile organic ... and enhance consumer acceptance (Guillaume et al.,. 2009; Lui et al., 2005).

  8. Sorption kinetics of selected volatile organic compounds in humin.

    Science.gov (United States)

    Shih, Yang-Hsin; Wu, Shian-Chee

    2002-10-01

    Each component of the chemically heterogeneous soil exhibits a unique sorption behavior toward organic sorbates. The sorption kinetics of some volatile organic compounds (VOCs) in pressed humin disks was investigated by tracking the weight change of the disks with a microbalance. Higher sorbing capacity for more polar VOCs as well as C13 nuclear magnetic resonance data indicates that humin was more hydrophilic than Aldrich humic acid (Milwaukee, WI, USA). The apparent diffusivity of acetone, toluene, and hexane in the disks ranged from 10(-8) to 10(-10) cm2/s. The sorbed toluene in humin does not seem persistent to desorption; however, acetone and hexane, either as polar or linear compounds in humin, show persistence against desorption. On completion of the desorption experiments, there were approximately 35 and 20% sorbate residue for acetone and hexane, respectively.

  9. Use of serially coupled capillary columns with different polarity of stationary phases for the separation of the natural complex volatile mixture of the marine red alga Corallina elongata.

    Science.gov (United States)

    Dembitsky, V M; Srebnik, M

    2002-09-01

    Separation of a complex of natural volatile compounds using serially coupled capillary columns with different polarity of stationary phases by gas chromatography-mass spectrometry from the medicinal marine red alga Corallina elongata is reported. Nearly 200 hydrocarbons, halogen compounds, fatty acids, and other metabolites were found. Using this gas chromatography procedure we demonstrate the successful separation of different volatile organic compounds.

  10. The fight against Volatile Organic Compounds (VOC)

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This paper strikes the balance of the fight against organic volatile compounds emissions in France and in Europe. The first part describes the influence of VOC on production of Ozone in troposphere and gives numerical data on permissive emission values in atmosphere. The second part describes french and european policy and regulations. The third part gives the principle methods and devices for COV measurement in the atmosphere. In the last part, effluents treatment is given: thermal incineration, catalytic incineration, adsorption on active carbon, biologic purification, condensation and separative processes on membrane

  11. TMVOC, simulator for multiple volatile organic chemicals

    International Nuclear Information System (INIS)

    Pruess, Karsten; Battistelli, Alfredo

    2003-01-01

    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

  12. Spatial variation of volatile organic compounds and carbon ...

    African Journals Online (AJOL)

    The study focused on methane volatile organic compounds and non-methane volatile compounds besides carbon monoxide. Results of the analysis showed that non-methane volatile compound levels were highest at public bus terminuses with 12.40 ± 0.83 ppm, and lowest for industrial locations (2.16 ± 0.09 ppm).

  13. Volatile organic carbon/air separation test using gas membranes

    International Nuclear Information System (INIS)

    King, C.V.; Kaschemekat, J.

    1993-08-01

    An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed

  14. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

    2002-06-01

    Western Research Institute (WRI) initiated exploratory work towards the development of new field screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of carbon-halogen bonds. Commercially available heated diode and corona discharge leak detectors were procured and evaluated for halogenated VOC response. The units were modified to provide a digital readout of signal related to VOC concentration. Sensor response was evaluated with carbon tetrachloride and tetrachloroethylene (perchloroethylene, PCE), which represent halogenated VOCs with and without double bonds. The response characteristics were determined for the VOCs directly in headspace in Tedlar bag containers. Quantitation limits in air were estimated. Potential interferences from volatile hydrocarbons, such as toluene and heptane, were evaluated. The effect of humidity was studied also. The performance of the new devices was evaluated in the laboratory by spiking soil samples and monitoring headspace for halogenated VOCs. A draft concept of the steps for a new analytical method was outlined. The results of the first year effort show that both devices show potential utility for future analytical method development work towards the goal of developing a portable test kit for screening halogenated VOCs in the field.

  15. Characterisation of selected volatile organic compounds in ...

    African Journals Online (AJOL)

    GCMS), was used to identify volatile compounds at three different temperatures. Fifty volatile compounds, inclusive of 14 acids, 14 alcohols, and 22 esters were identified and quantified in the two brands of indigenous banana beer samples. Only 12 ...

  16. Methods for Reducing Volatile Organic Content in Fabric Waterproof Coatings

    National Research Council Canada - National Science Library

    Keohan, Francis

    1994-01-01

    .... Regulatory pressure for environmental protection and worker safety has become a potent driving force in eliminating volatile organic solvents and toxic additives from commercial coating products...

  17. Climate, atmosphere, and volatile inventory evolution: polar processes, climate records, volatile inventories

    International Nuclear Information System (INIS)

    Pollack, J.B.

    1988-01-01

    Climate change on Mars was driven by long term changes in the solar luminosity, variations in the partitioning of volatiles between the atmosphere and near-surface reservoirs, and astronomical variations in axial and orbital properties. There are important parallels between these drives for Mars and comparable ones for Earth. In the early history of the solar system, the Sun's luminosity was 25 to 30 percent lower than its current value. It is suggested that an early benign climate on Earth was due to the presence of much more carbon dioxide in its atmosphere at these early times than currently resides there. Such a partitioning of carbon dioxide, at the expense of the carbonate rock reservoir, may have resulted from a more vigorous tectonic and volcanic style at early times. Such a line of reasoning may imply that much more carbon dioxide was present in the Martian atmosphere during the planet's early history than resides there today. It is now widely recognized that astronomical variations of the Earth's axial and orbital characteristics have played a dominant role in causing the succession of glacial and interglacial periods characterizing the last several million years. The magnitude of the axial and eccentricity variations are much larger for Mars than for Earth. Such changes on Mars could result in sizeable variations in atmospheric pressure, dust storm activity, and the stability of perennial carbon dioxide and water ice polar caps. These quasi-periodic climate changes occur on periods of 100,000 to 1,000,000 years and may be recorded in the sedimentary layers of the polar layered terrain

  18. Volatile organic monitor for industrial effluents

    International Nuclear Information System (INIS)

    Laguna, G.R.; Peter, F.J.; Stuart, A.D.; Loyola, V.M.

    1993-07-01

    1990 amendments to the Clean Air Act have created the need for instruments capable of monitoring volatile organic compounds (VOCS) in public air space in an unattended and low cost manner. The purpose of the study was to develop and demonstrate the capability to do long term automatic and unattended ambient air monitoring using an inexpensive portable analytic system at a commercial manufacturing plant site. A gas chromatograph system personal computer hardware, meteorology tower ampersand instruments, and custom designed hardware and software were developed. Comparison with an EPA approved method was performed. The system was sited at an aircraft engines manufacturing site and operated in a completely unattended mode for 60 days. Two VOCs were monitored every 30 minutes during the 24hr day. Large variation in the concentration from 800ppb to the limits of detection of about 10ppb were observed. Work to increase the capabilities of the system is ongoing

  19. POLAR ORGANIC CHEMICAL INTEGRATIVE SAMPLING ...

    Science.gov (United States)

    The purpose of the research presented in this paper is two-fold: (1) to demonstrate the 4 coupling of two state-of-the-art techniques: a time-weighted polar organic integrative sampler (POCIS) and micro-liquid chromatography-electrospray/ion trap mass spectrometry (u-LC-6 ES/ITMS); and (2) the assessment of these methodologies in a real-world environment -wastewater effluent - for detecting six drugs (four prescription and two illicit). In the effluent from three wastewater treatment plants (WWTP), azithromycin was detected at concentrations ranging from 15ng/L to 66ng/L, equivalent to the total annual release of 0.4 -4 kg into the receiving waters. Detected and confirmed in the effluent from two WWTPs were two illicit drugs methamphetamine and methylenedioxymethamphetamine (MDMA), at 2ng/L and 0.5ng/L, respectively. While the ecotoxicological significance of drugs in environmental matrices, particularly water, has not been closely examined, it can only be surmised that these substances have the potential to adversely affect biota that are continuously exposed to them even at very low levels. The potential for chronic affects on human health is also unknown, but of increasing concern due to the multi use character of water, particularly in densely populated arid areas. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality

  20. Atmospheric transformation of volatile organic compounds

    Science.gov (United States)

    Henley, Michael V.; Bradley, William R.; Wyatt, Sheryl E.; Graziano, G. M.; Wells, J. R.

    2000-07-01

    To be able to understand and predict the concentration of a target compound in the atmosphere one must understand the atmospheric chemistry involved. The transformation of volatile organic compounds in the troposphere is predominantly driven by the interaction with the hydroxyl and nitrate radicals. The hydroxyl radical exists in daylight conditions and its reaction rate constant with an organic compound is typically very fast. The nitrate radical drives the nighttime chemistry. These radicals can scavenge hydrogen from an organic molecule generating secondary products that are often overlooked in detection schemes. Secondary products can be more stable and serve as a better target compound in detection schemes. The gas phase reaction of the hydroxyl radical (OH) with cyclohexanol (COL) has been studied. The rate coefficient was determined to be (19.0 +/- 4.8) X 10-12 cm3 molecule-1 s-1 (at 297 +/- 3 K and 1 atmosphere total pressure) using the relative rate technique with pentanal, decane, and tridecane as the reference compounds. Assuming an average OH concentration of 1 X 106 molecules cm-3, an atmospheric lifetime of 15 h is calculated for cyclohexanol. Products of the OH + COL reaction were determined to more clearly define cyclohexanol's atmospheric degradation mechanism. The observed products were: cyclohexanone, hexanedial, 3- hydroxycyclohexanone, and 4-hydroxycyclohexanone. Consideration of the potential reaction pathways suggest that each of these products is formed via hydrogen abstraction at a different site on the cyclohexanol ring.

  1. Volatile Organic Compound Analysis in Istanbul

    Science.gov (United States)

    Ćapraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Coşkun, M.

    2012-04-01

    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, Nişantaşı, 34365, İstanbul, 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 Kağıthane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Kağıthane 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

  2. Volatile organic compound emissions from engineered wood products

    Science.gov (United States)

    Steve Zylkowski; Charles Frihart

    2017-01-01

    Thirteen bonded engineered wood products representing those commonly used in building construction were evaluated for volatile organic chemicals using methods developed for interior bonded wood products. Although formaldehyde and acetaldehyde were emitted from all samples, they were not the dominant volatiles, which greatly depended on wood species and bonding...

  3. Organic non-volatile memories from ferroelectric phase-separated blends

    Science.gov (United States)

    Asadi, Kamal; de Leeuw, Dago M.; de Boer, Bert; Blom, Paul W. M.

    2008-07-01

    New non-volatile memories are being investigated to keep up with the organic-electronics road map. Ferroelectric polarization is an attractive physical property as the mechanism for non-volatile switching, because the two polarizations can be used as two binary levels. However, in ferroelectric capacitors the read-out of the polarization charge is destructive. The functionality of the targeted memory should be based on resistive switching. In inorganic ferroelectrics conductivity and ferroelectricity 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. Here we present an integrated solution by blending semiconducting and ferroelectric polymers into phase-separated networks. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor-metal contact. The combination of ferroelectric bistability with (semi)conductivity and rectification allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read out non-destructively. The concept of an electrically tunable injection barrier as presented here is general and can be applied to other electronic devices such as light-emitting diodes with an integrated on/off switch.

  4. Ices on Mercury: Chemistry of volatiles in permanently cold areas of Mercury's north polar region

    Science.gov (United States)

    Delitsky, M. L.; Paige, D. A.; Siegler, M. A.; Harju, E. R.; Schriver, D.; Johnson, R. E.; Travnicek, P.

    2017-01-01

    Observations by the MESSENGER spacecraft during its flyby and orbital observations of Mercury in 2008-2015 indicated the presence of cold icy materials hiding in permanently-shadowed craters in Mercury's north polar region. These icy condensed volatiles are thought to be composed of water ice and frozen organics that can persist over long geologic timescales and evolve under the influence of the Mercury space environment. Polar ices never see solar photons because at such high latitudes, sunlight cannot reach over the crater rims. The craters maintain a permanently cold environment for the ices to persist. However, the magnetosphere will supply a beam of ions and electrons that can reach the frozen volatiles and induce ice chemistry. Mercury's magnetic field contains magnetic cusps, areas of focused field lines containing trapped magnetospheric charged particles that will be funneled onto the Mercury surface at very high latitudes. This magnetic highway will act to direct energetic protons, ions and electrons directly onto the polar ices. The radiation processing of the ices could convert them into higher-order organics and dark refractory materials whose spectral characteristics are consistent with low-albedo materials observed by MESSENGER Laser Altimeter (MLA) and RADAR instruments. Galactic cosmic rays (GCR), scattered UV light and solar energetic particles (SEP) also supply energy for ice processing. Cometary impacts will deposit H2O, CH4, CO2 and NH3 raw materials onto Mercury's surface which will migrate to the poles and be converted to more complex Csbnd Hsbnd Nsbnd Osbnd S-containing molecules such as aldehydes, amines, alcohols, cyanates, ketones, hydroxides, carbon oxides and suboxides, organic acids and others. Based on lab experiments in the literature, possible specific compounds produced may be: H2CO, HCOOH, CH3OH, HCO, H2CO3, CH3C(O)CH3, C2O, CxO, C3O2, CxOy, CH3CHO, CH3OCH2CH2OCH3, C2H6, CxHy, NO2, HNO2, HNO3, NH2OH, HNO, N2H2, N3, HCN, Na2O, Na

  5. Biogenic volatile organic compounds - small is beautiful

    Science.gov (United States)

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

    2012-12-01

    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 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 (α-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, α-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

  6. Volatile and semivolatile organic compounds in laboratory peat fire emissions

    Data.gov (United States)

    U.S. Environmental Protection Agency — Supporting information Tables S3 and S4 list emission factors in g/kg of speciated volatile and particulate organic compounds emitted from peat burning. Peat samples...

  7. Variability of volatile organic compounds emitted by seedlings of ...

    African Journals Online (AJOL)

    Variability of volatile organic compounds emitted by seedlings of seven African maize varieties when infested by adult Cicadulina storeyi China leafhopper vectors of maize streak virus. S Oluwafemi, MA Birkett, J Caulfield, JA Pickett ...

  8. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    John F. Schabron; Joseph F. Rovani, Jr.; Theresa M. Bomstad

    2003-07-01

    Western Research Institute (WRI) is continuing work toward the development of new screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of halogens. In prior work, the devices were tested for response to carbon tetrachloride, heptane, toluene, and water vapors. In the current work, sensor response was evaluated with sixteen halogenated VOCs relative to carbon tetrachloride. The results show that the response of the various chlorinated VOCs is within an order of magnitude of the response to carbon tetrachloride for each of the sensors. Thus, for field screening a single response factor can be used. Both types of leak detectors are being further modified to provide an on-board LCD signal readout, which is related to VOC concentration. The units will be fully portable and will operate with 115-V line or battery power. Signal background, noise level, and response data on the Bacharach heated diode detector and the TIF corona discharge detector show that when the response curves are plotted against the log of concentration, the plot is linear to the upper limit for the particular unit, with some curvature at lower levels. When response is plotted directly against concentration, the response is linear at the low end and is curved at the high end. The dynamic ranges for carbon tetrachloride of the two devices from the lower detection limit (S/N=2) to signal saturation are 4-850 vapor parts per million (vppm) for the corona discharge unit and 0.01-70 vppm for the heated diode unit. Additional circuit modifications are being made to lower the detection limit and increase the dynamic response range of the corona discharge unit. The results indicate that both devices show potential utility for future analytical method development work toward

  9. Volatilization of volatile organic compounds from showers—I. Analytical method and quantitative assessment

    Science.gov (United States)

    Tancrède, M.; Yanagisawa, Y.; Wilson, R.

    To provide data to test mathematical models developed to predict human exposure to Volatile Organic Compounds (VOCs) volatilizing from showers, an analytical method was developed to analyze the simultaneous volatilization of VOCs in the water and humid air of showers. Five VOCs with a wide range of Henry's law constants were used. Experiments, conducted in a full-scale shower, were performed at initial water concentrations nearing tap water VOC concentrations (a few μgλ -1). VOCs in water and humid air samples were concentrated by purge-and-trap, thermally desorbed from a Tenax trap and analyzed with a gas chromatograph-electron capture detector. The fraction of the VOCs volatilized from showers at various water temperatures and flow rates were calculated. Mass-balane equations indicated the presence of sinks of VOCs in the experimental shower other than those due to the airflow. An experimental method to measure the residence time of the water in the shower is presented.

  10. Organic and volatile elements in the solar system

    Directory of Open Access Journals (Sweden)

    Remusat L.

    2012-01-01

    Full Text Available Chondrites and comets have accreted primitive materials from the early solar system. Those materials include organics, water and other volatile components. The most primitive chondrites and comets have undergone few modifications on their respective parent bodies and can deliver to laboratories components that were present at the origin of the protosolar nebula. Here I present a review of the organic material and volatile components that have been studied in the most primitive chondrites, and the last data from the stardust mission about the cometary record. This paper focuses on materials that can be studied in laboratories, by mass spectrometry, ion probes or organic chemistry techniques.

  11. Quantifying commuter exposures to volatile organic compounds

    Science.gov (United States)

    Kayne, Ashleigh

    Motor-vehicles can be a predominant source of air pollution in cities. Traffic-related air pollution is often unavoidable for people who live in populous areas. Commuters may have high exposures to traffic-related air pollution as they are close to vehicle tailpipes. Volatile organic compounds (VOCs) are one class of air pollutants of concern because exposure to VOCs carries risk for adverse health effects. Specific VOCs of interest for this work include benzene, toluene, ethylbenzene, and xylenes (BTEX), which are often found in gasoline and combustion products. Although methods exist to measure time-integrated personal exposures to BTEX, there are few practical methods to measure a commuter's time-resolved BTEX exposure which could identify peak exposures that could be concealed with a time-integrated measurement. This study evaluated the ability of a photoionization detector (PID) to measure commuters' exposure to BTEX using Tenax TA samples as a reference and quantified the difference in BTEX exposure between cyclists and drivers with windows open and closed. To determine the suitability of two measurement methods (PID and Tenax TA) for use in this study, the precision, linearity, and limits of detection (LODs) for both the PID and Tenax TA measurement methods were determined in the laboratory with standard BTEX calibration gases. Volunteers commuted from their homes to their work places by cycling or driving while wearing a personal exposure backpack containing a collocated PID and Tenax TA sampler. Volunteers completed a survey and indicated if the windows in their vehicle were open or closed. Comparing pairs of exposure data from the Tenax TA and PID sampling methods determined the suitability of the PID to measure the BTEX exposures of commuters. The difference between BTEX exposures of cyclists and drivers with windows open and closed in Fort Collins was determined. Both the PID and Tenax TA measurement methods were precise and linear when evaluated in the

  12. Volatile organic compounds and oxides of nitrogen. Further emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Froste, H. [comp.

    1996-12-31

    This report presents the current status in relation to achievement of the Swedish Environmental target set by Parliament to reduce emission of volatile organic compounds by 50 per cent between 1988 and 2000. It also instructed the Agency to formulate proposed measures to achieve a 50 per cent reduction of emission of nitrogen oxides between 1985 and 2005. The report presents an overall account of emission trends for volatile organic compounds (from all sectors) and nitrogen oxides (from the industry sector) and steps proposed to achieve further emission reductions. 43 refs

  13. Production of fungal volatile organic compounds in bedding materials

    OpenAIRE

    S. LAPPALAINEN; A. PASANEN; P. PASANEN

    2008-01-01

    The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO 2 production as indicators. The volatile organic compounds were collected into Tenax resin a...

  14. Inventory of volatile organic compound emissions in Finland, 1985

    International Nuclear Information System (INIS)

    Mroueh, U.M.

    1988-01-01

    The aim of the study was to compile an inventory of the emissions of volatile organic compounds in Finland for the year 1985. The report was prepared for the ECE Task Force on Emissions of Volatile Organic Compounds from Stationary Sources according to the classification given by the Task Force. It considers anthropogenic as well as natural sources. Mobile sources are excluded. The quantities as well as the main components are listed, as far as possible. The values given exclude methane which according to the present understanding is regarded as unreactive

  15. Spatial variation of volatile organic compounds and carbon ...

    African Journals Online (AJOL)

    GREG

    2013-05-12

    May 12, 2013 ... carbon monoxide in Blantyre City, Malawi. Mapoma, H. W. T.1*, Zimba J. J. 2, Utembe ... This study assessed variations of ambient volatile organic compounds and carbon monoxide (CO) levels in Blantyre City, Malawi. .... the ground to capture maximum emissions from both vehicles and industrial sources.

  16. ambient volatile organic compounds pollution and ozone formation

    African Journals Online (AJOL)

    OLUMAYEDE

    2013-08-01

    Aug 1, 2013 ... Volatile organic compound (VOC) species react at different rate and exhibit differences in reactivity with respect to ozone formation in polluted urban atmosphere. To assess this, the variations pattern, reactivity relative to OH radical and ozone creation potential of ambient VOCs were investigated in field.

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

    Science.gov (United States)

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

  18. Total volatile organic compounds (TVOC) in indoor air quality investigations

    DEFF Research Database (Denmark)

    Mølhave, L.; Clausen, Geo; Berglund, B.

    1997-01-01

    The amount of volatile organic compounds (VOCs) in indoor air, usually called TVOC (total volatile organic compounds), has been measured using different definitions and techniques which yield different results. This report recommends a definition of TVOC referring to a specified range of VOCs and...... for characterizing indoor pollution and for improving source control as required from the points of view of health, comfort, energy efficiency and sustainability. (C) Indoor Air (1997)....... the TVOC value. The report reviews the TVOC concept with respect to its usefulness for exposure assessment and control and for the prediction of health or comfort effects. Although the report concludes that at present it is not possible to use TVOC as an effect predictor, it affirms the usefulness of TVOC......The amount of volatile organic compounds (VOCs) in indoor air, usually called TVOC (total volatile organic compounds), has been measured using different definitions and techniques which yield different results. This report recommends a definition of TVOC referring to a specified range of VOCs...

  19. 40 CFR 60.542 - Standards for volatile organic compounds.

    Science.gov (United States)

    2010-07-01

    ... Rubber Tire Manufacturing Industry § 60.542 Standards for volatile organic compounds. (a) On and after... cementing operation: Discharge into the atmosphere no more than 10 grams (0.022 lb) of VOC per tire cemented... grams (0.011 lb) of VOC per bead cemented for each month. (5) For each green tire spraying operation...

  20. air quality status of volatile organic compounds in health and ...

    African Journals Online (AJOL)

    BARTH EKWUEME

    Volatile organic compounds are considered to be air toxins that affect human health. They have great influence on the troposphere because they affect the formation of ozone. Ambient air samples were collected from indoor and outdoor of five health and financial institution microenvironments. Passive sampling method with ...

  1. Volatile Organic Compunds (Environmental Health Student Portal)

    Science.gov (United States)

    ... Pesticides Climate Change Climate Change Home What is Climate Change ... organic compounds ( VOCs ) are chemicals that evaporate from a solid or liquid form at room temperature. Some VOCs exist naturally in the environment. Others are manufactured (made by people) and put ...

  2. Size-dependence of volatile and semi-volatile organic carbon content in phytoplankton cells

    Directory of Open Access Journals (Sweden)

    Sergio eRuiz-Halpern

    2014-07-01

    Full Text Available The content of volatile and semivolatile organic compounds (VOC and SOC, measured as exchangeable dissolved organic carbon (EDOC, was quantified in 9 phytoplanktonic species that spanned 4 orders of magnitude in cell volume, by disrupting the cells and quantifying the gaseous organic carbon released. EDOC content varied 4 orders of magnitude, from 0.0015 to 14.12 pg C cell-1 in the species studied and increased linearly with increasing phytoplankton cell volume following the equation EDOC (pg C cell-1 = -2.35 x cellular volume (CV, µm3 cell-1 0.90 (± 0.3, with a slope (0.90 not different from 1 indicating a constant increase in volatile carbon as the cell size of phytoplankton increased. The percentage of EDOC relative to total cellular carbon was small but varied 20 fold from 0.28 % to 5.17 %, and no obvious taxonomic pattern in the content of EDOC was appreciable for the species tested. The cell release rate of EDOC is small compared to the amount of carbon in the cell and difficult to capture. Nonetheless, the results point to a potential flux of volatile and semivolatile phytoplankton-derived organic carbon to the atmosphere that has been largely underestimated and deserves further attention in the future.

  3. Nanostructured Polypyrrole-Based Ammonia and Volatile Organic Compound Sensors

    Directory of Open Access Journals (Sweden)

    Milena Šetka

    2017-03-01

    Full Text Available The aim of this review is to summarize the recent progress in the fabrication of efficient nanostructured polymer-based sensors with special focus on polypyrrole. The correlation between physico-chemical parameters, mainly morphology of various polypyrrole nanostructures, and their sensitivity towards selected gas and volatile organic compounds (VOC is provided. The different approaches of polypyrrole modification with other functional materials are also discussed. With respect to possible sensors application in medicine, namely in the diagnosis of diseases via the detection of volatile biomarkers from human breath, the sensor interaction with humidity is described as well. The major attention is paid to analytes such as ammonia and various alcohols.

  4. A large source of low-volatility secondary organic aerosol

    DEFF Research Database (Denmark)

    Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard

    2014-01-01

    -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...... 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 α-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...

  5. Quantitative estimates of the volatility of ambient organic aerosol

    Science.gov (United States)

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

    2010-06-01

    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 (ΔHvap). 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 ΔHvap assumptions are considered. The sensitivity of the total OA mass to dilution and ambient changes in temperature has been assessed for the various ΔHvap assumptions. The temperature sensitivity is relatively independent of the particular ΔHvap assumptions whereas dilution sensitivity is found to be greatest for the low (ΔHvap = 50 kJ/mol) and lowest for the high (ΔHvap = 150 kJ/mol) assumptions. This difference arises from the high ΔHvap assumptions yielding volatility distributions with a greater fraction of non-volatile material than the low ΔHvap 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 ΔHvap assumptions. Our results also show that the amount of semivolatile gas-phase organics in equilibrium with the OA could range from ~20

  6. Diffusivity measurements of volatile organics in levitated viscous aerosol particles

    Directory of Open Access Journals (Sweden)

    S. Bastelberger

    2017-07-01

    Full Text Available Field measurements indicating that atmospheric secondary organic aerosol (SOA particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas–particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4 is investigated in an electrodynamic balance at controlled relative humidity (RH and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes–Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities < 10−14 cm2 s−1 at temperatures < 15 °C. The temperature dependence is strong, suggesting a diffusion activation energy of about 300 kJ mol−1. We conclude that atmospheric volatile organic compounds can be subject to severe diffusion limitations in viscous organic aerosol particles. This may enable an important long-range transport mechanism for organic material, including pollutant molecules such as polycyclic aromatic hydrocarbons (PAHs.

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

    International Nuclear Information System (INIS)

    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

    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 4 ) contamination located near the center of the Hanford Site. The movement of CCl 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

  8. Adsorption of volatile organic compounds by polytetra-fluor ethylene

    International Nuclear Information System (INIS)

    Martinet, J.M.

    1958-01-01

    The sorption of organic vapours by microporous polytetra-fluor ethylene has been studied gravimetrically using a Mc Bain-Baker type sorption balance. The amount of sorption, the peculiarities observed on the isotherm curves, the small influence of temperature, and smallness of hysteresis suggests that mainly physical adsorption occurs when the temperature is around 25 deg. C. The values of the surface areas obtained from the adsorption isotherms using organic vapours differ greatly from those derived from N 2 adsorption measurements. This discrepancy cannot be completely attributed to differences in the structure and chemical function of the adsorbate molecules, or to the porous structure of the adsorbent. On the contrary, the surface area values obtained by sorbing high volatile freons conform with those measured by nitrogen adsorption, which seems to imply a connection between the area of sorbed monolayers and volatility of the adsorbate. (author) [fr

  9. Volatile organic compound optical fiber sensors: a review

    OpenAIRE

    Elosúa Aguado, César; Matías Maestro, Ignacio; Bariáin Aisa, Cándido; Arregui San Martín, Francisco Javier

    2006-01-01

    Volatile organic compound (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chemical industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its minimum invasive nature and the advantages that optical fiber offers such as light weight, passive nature, low attenuation and the...

  10. Beyond the network of plants volatile organic compounds

    OpenAIRE

    Vivaldo, Gianna; Masi, Elisa; Taiti, Cosimo; Caldarelli, Guido; Mancuso, Stefano

    2017-01-01

    Plants emission of volatile organic compounds (VOCs) is involved in a wide class of ecological functions, as VOCs play a crucial role in plants interactions with biotic and abiotic factors. Accordingly, they vary widely across species and underpin differences in ecological strategy. In this paper, VOCs spontaneously emitted by 109 plant species (belonging to 56 different families) have been qualitatively and quantitatively analysed in order to classify plants species. By using bipartite netwo...

  11. Marine Vibrio Species Produce the Volatile Organic Compound Acetone

    OpenAIRE

    Nemecek-Marshall, M.; Wojciechowski, C.; Kuzma, J.; Silver, G. M.; Fall, R.

    1995-01-01

    While screening aerobic, heterotrophic marine bacteria for production of volatile organic compounds, we found that a group of isolates produced substantial amounts of acetone. Acetone production was confirmed by gas chromatography, gas chromatography-mass spectrometry, and high-performance liquid chromatography. The major acetone producers were identified as nonclinical Vibrio species. Acetone production was maximal in the stationary phase of growth and was stimulated by addition of l-leucine...

  12. Production of fungal volatile organic compounds in bedding materials

    Directory of Open Access Journals (Sweden)

    S. LAPPALAINEN

    2008-12-01

    Full Text Available The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO 2 production as indicators. The volatile organic compounds were collected into Tenax resin and analysed by gas chromatography. Several microbial volatile organic compounds (MVOCs, e.g. 1-butanol, 2-hexanone, 2-heptanone, 3-octanone, 1-octen-3-ol and 1-octanol were detected in laboratory experiments; however, these accounted for only 0.08-1.5% of total volatile organic com-pounds (TVOCs. Emission rates of MVOCs were 0.001-0.176 mg/kg of bedding materials per hour. Despite some limitations of the analytical method, certain individual MVOCs, 2-hexanone, 2-hep-tanone and 3-octanone, were also detected in concentrations of less than 4.6 mg/m 3 (0.07-0.31% of TVOC in a horse stable where peat and shavings were used as bedding materials. MVOC emission rate was estimated to be 0.2-2.0 mg/kg ´ h -1 from bedding materials in the stable, being about ten times higher than the rates found in the laboratory experiments. Some compounds, e.g. 3-octanone and 1-octen-3-ol, can be assumed to originate mainly from microbial metabolisms.;

  13. Volatile organic components from fresh non-edible Basidiomycetes fungi.

    Science.gov (United States)

    Piovano, Marisa; Garbarino, Juan A; Sánchez, Elizabeth; Young, Manuel E

    2009-12-01

    The compounds responsible for the characteristic odor of eight fresh non-edible Basidiomycetes fungi were evaluated. The volatile organic compounds from the fresh samples present in the headspace of a sealed vial were determined by solid-phase microextraction gas chromatography-mass spectrometry, using a PDMS/DVB fiber. A total of twenty-eight components were identified, the most frequent being 1-octen-3-ol and 3-octanone.

  14. Transport and Fate of Volatile Organic Chemical in Soils

    DEFF Research Database (Denmark)

    Petersen, Lis Wollesen

    Recently much attention has been paid to the behavior of volatile organic chemicals (VOCs) in the environment. This is due to the fact that the environmental pollution with these hazardous chemicals has drastically increased during the last decades. The present study is limited to consider...... the transport and fate of VOCs in the gaseous phase, thus contributing to the overall understanding of VOCs behavior in soil, which eventually will facilitate future cleanup....

  15. Volatile organic pollutants in iron and steel industry

    International Nuclear Information System (INIS)

    Manea, D.; Dorina, S.; Popescu, L.; Stoian, P.

    2009-01-01

    It is a well known fact that iron and steel units generate about 25% from total gaseous emissions, and a significant part of these are diffuse emissions, which appear during technological stages. so that, apart from other types of pollutants, appear volatile organic compounds (VOCs) that contain a considerable number of diverse and complex substances that, even in small amounts, affect all environmental factors: air, water, soil. (Author)

  16. Evaluation of a completely automated cold fiber device using compounds with varying volatility and polarity.

    Science.gov (United States)

    Jiang, Ruifen; Carasek, Eduardo; Risticevic, Sanja; Cudjoe, Erasmus; Warren, Jamie; Pawliszyn, Janusz

    2012-09-12

    A fully automated cold fiber solid phase microextraction device has been developed by coupling to a GERSTEL multipurpose (MPS 2) autosampler and applied to the analysis of volatiles and semi-volatiles in aqueous and solid matrices. The proposed device was thoroughly evaluated for its extraction performance, robustness, reproducibility and reliability by gas chromatograph/mass spectrometer (GC/MS). With the use of a septumless head injector, the entire automated setup was capable of analyzing over 200 samples without any GC injector leakages. Evaluation of the automated cold fiber device was carried out using a group of compounds characterized by different volatilities and polarities. Extraction efficiency as well as analytical figures of merit was compared to commercial solid phase microextraction fibers. The automated cold fiber device showed significantly improved extraction efficiency compared to the commercial polydimethylsiloxane (PDMS) and cold fiber without cooling for the analysis of aqueous standard samples due to the low temperature of the coating. Comparing results obtained from cold fiber and commercial divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber temperature profile demonstrated that the temperature gap between the sample matrix and the coating improved the distribution coefficient and therefore the extraction amount. The linear dynamic range of the cold fiber device was 0.5 ng mL(-1) to 100 ng mL(-1) with a linear regression coefficient ≥0.9963 for all compounds. The limit of detection for all analytes ranged from 1.0 ng mL(-1) to 9.4 ng mL(-1). The newly automated cold fiber device presents a platform for headspace analysis of volatiles and semi-volatiles for large number of samples with improved throughput and sensitivity. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Determination of Volatile Organic Compounds in Selected Strains of Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Ivan Milovanović

    2015-01-01

    Full Text Available Microalgal biomass can be used in creating various functional food and feed products, but certain species of microalgae and cyanobacteria are known to produce various compounds causing off-flavour. In this work, we investigated selected cyanobacterial strains of Spirulina, Anabaena, and Nostoc genera originating from Serbia, with the aim of determining the chemical profile of volatile organic compounds produced by these organisms. Additionally, the influence of nitrogen level during growth on the production of volatile compounds was investigated for Nostoc and Anabaena strains. In addition, multivariate techniques, namely, principal component analysis (PCA and hierarchical cluster analysis (HCA, were used for making distinction among different microalgal strains. The results show that the main volatile compounds in these species are medium chain length alkanes, but other odorous compounds such as 2-methylisoborneol (0.51–4.48%, 2-pentylfuran (0.72–8.98%, β-cyclocitral (0.00–1.17%, and β-ionone (1.15–2.72% were also detected in the samples. Addition of nitrogen to growth medium was shown to negatively affect the production of 2-methylisoborneol, while geosmin was not detected in any of the analyzed samples, which indicates that the manipulation of growth conditions may be useful in reducing levels of some unwanted odor-causing components.

  18. Thermal Stability of Frozen Volatiles in the North Polar Region of Mercury

    Science.gov (United States)

    Paige, David A.; Siegler, Matthew A.; Harmon, John K.; Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Solomon, Sean C.

    2012-01-01

    Earth-based radar observations have revealed the presence on Mercury of anomalously bright, depolarizing features that appear to be localized in the permanently shadowed regions of high-latitude impact craters [1]. Observations of similar radar signatures over a range of radar wavelengths implies that they correspond to deposits that are highly transparent at radar wavelengths and extend to depths of several meters below the surface [1]. Thermal models using idealized crater topographic profiles have predicted the thermal stability of surface and subsurface water ice at these same latitudes [2]. One of the major goals of the MESSENGER mission is to characterize the nature of radar-bright craters and presumed associated frozen volatile deposits at the poles of Mercury through complementary orbital observations by a suite of instruments [3]. Here we report on an examination of the thermal stability of water ice and other frozen volatiles in the north polar region of Mercury using topographic profiles obtained by the Mercury Laser Altimeter (MLA) instrument [4] in conjunction with a three-dimensional ray-tracing thermal model previously used to study the thermal environment of polar craters on the Moon [5].

  19. Monitoring organic volatiles and flammable gases with a holographic sensor

    Science.gov (United States)

    Martínez-Hurtado, J. L.; Davidson, C. A. B.; Lowe, C. R.

    2011-05-01

    There is an increasing preoccupation regarding the effects of organic volatiles or explosive gases in human welfare and society. A holographic sensor for gaseous and volatile compounds was produced by diffusion of silver salts in a silicon elastomer (PDMS). The salts were reduced to produce silver particles, which upon ablation with a pulsed laser form fringes of nano-sized silver grains. The fringes are separated by about half of the wavelength of the laser (266nm) producing a photonic effect that can be measured as a colorful reflection. A CCD spectrophotometer was used to detect the reflected wavelength of the hologram illuminated with a white light source. The molecular affinity of PDMS for organic molecules can be expressed as intermolecular forces in terms of the cohesive energy density. This parameter is used to predict with great accuracy the sensor performance. Hydrocarbon gases at different concentrations were tested for 3 sets of temperatures. Alkanes, alkenes and alkynes containing 2 to 4 carbon atoms were detected. The sensor responds in less than 5s to the hydrocarbon gas presence in a range of concentrations from 0% to 100% (v/v). Liquid organic compounds exhibit a slower response; however, the results agree with the prediction imposed by the cohesive energy densities. The capabilities of the sensor make it ideal for applications in indoor environment monitoring or dangerous environments enriched with such organic compounds.

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

    Directory of Open Access Journals (Sweden)

    Joan W. Bennett

    2015-09-01

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

  1. Volatile organic compounds in the unsaturated zone from radioactive wastes

    Science.gov (United States)

    Baker, Ronald J.; Andraski, Brian J.; Stonestrom, David A.; Luo, Wentai

    2012-01-01

    Volatile organic compounds (VOCs) are often comingled with low-level radioactive wastes (LLRW), but little is known about subsurface VOC emanations from LLRW landfills. The current study systematically quantified VOCs associated with LLRW over an 11-yr period at the USGS Amargosa Desert Research Site (ADRS) in southwestern Nevada. Unsaturated-zone gas samples of VOCs were collected by adsorption on resin cartridges and analyzed by thermal desorption and GC/MS. Sixty of 87 VOC method analytes were detected in the 110-m-thick unsaturated zone surrounding a LLRW disposal facility. Chlorofluorocarbons (CFCs) were detected in 100% of samples collected. Chlorofluorocarbons are powerful greenhouse gases, deplete stratospheric ozone, and are likely released from LLRW facilities worldwide. Soil-gas samples collected from a depth of 24 m and a horizontal distance 100 m south of the nearest waste-disposal trench contained >60,000 ppbv total VOCs, including >37,000 ppbv CFCs. Extensive sampling in the shallow unsaturated zone (0–2 m deep) identified areas where total VOC concentrations exceeded 5000 ppbv at the 1.5-m depth. Volatile organic compound concentrations exceeded background levels up to 300 m from the facility. Maximum vertical diffusive fluxes of total VOCs were estimated to be 1 g m-2 yr-1. Volatile organic compound distributions were similar but not identical to those previously determined for tritium and elemental mercury. To our knowledge, this study is the first to characterize the unsaturated zone distribution of VOCs emanating from a LLRW landfill. Our results may help explain anomalous transport of radionuclides at the ADRS and elsewhere.

  2. Water-Air Volatilization Factors to Determine Volatile Organic Compound (VOC Reference Levels in Water

    Directory of Open Access Journals (Sweden)

    Vicenç Martí

    2014-06-01

    Full Text Available The goal of this work is the modeling and calculation of volatilization factors (VFs from water to air for volatile organic compounds (VOCs in order to perform human health risk-based reference levels (RLs for the safe use of water. The VF models have been developed starting from the overall mass-transfer coefficients (Koverall concept from air to water for two interaction geometries (flat surface and spherical droplets in indoor and outdoor scenarios. For a case study with five groups of risk scenarios and thirty VOCs, theoretical VFs have been calculated by using the developed models. Results showed that Koverall values for flat and spherical surface geometries were close to the mass transfer coefficient for water (KL when Henry’s law constant (KH was high. In the case of spherical drop geometry, the fraction of volatilization (fV was asymptotical when increasing KH with fV values also limited due to Koverall. VFs for flat surfaces were calculated from the emission flux of VOCs, and results showed values close to 1000KH for the most conservative indoor scenarios and almost constant values for outdoor scenarios. VFs for spherical geometry in indoor scenarios followed also constant VFs and were far from 1000KH. The highest calculated VF values corresponded to the E2A, E2B, E3A and E5A scenarios and were compared with experimental and real results in order to check the goodness of flat and sphere geometry models. Results showed an overestimation of calculated values for the E2A and E2B scenarios and an underestimation for the E3A and E5A scenarios. In both cases, most of the calculated VFs were from 0.1- to 10-times higher than experimental/real values.

  3. Synthesis of Carbon Nanotubes and Volatile Organic Compounds Detection

    Directory of Open Access Journals (Sweden)

    Sobri S.

    2016-01-01

    Full Text Available In this work, the adsorption effect of volatile organic compounds (chloroacetophenone, acetonitrile and hexane towards the change of resistance of CNTs pellet as sensor signal was investigated. CNTs used in this research were synthesized using Floating Catalyst – Chemical Vapor Deposition (FC-CVD method in optimum condition. The synthesized CNTs were characterized using Scanning Electron Microscopy (SEM, Transmission Electron Microscopy (TEM and Raman Spectroscopy. The variation of resistance changes towards the tested gases were recorded using a multimeter. CNTs sensor pellet showed good responses towards the tested gases, however, the sensitivity, response time and recovery time of sensor pellet need to be optimized.

  4. Electron beam treatment of toxic volatile organic compounds and dioxins

    International Nuclear Information System (INIS)

    Kojima, Takuji

    2006-01-01

    Considerations of wastes based on the reduction, reuse and recycle in daily life are primary measures to conserve our environment, but the control technology is necessary to support these measures. The electron beam (EB) process is promising as an advanced purification process having advantages such as a quick treatment of big volume gas, applicability even for very low concentration pollutants as the further purification at the downstream of existing process, and decomposition of pollutants into non-toxic substances by one process. The EB technology has been developed for treatment of toxic volatile organic compounds (VOCs) in ventilation gas and dioxins in solid waste incineration flue gas. (author)

  5. Stability of volatile organics in environmental soil samples. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

    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.

  6. Stability of volatile organics in environmental soil samples

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

    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.

  7. Emission of Biogenic Volatile Organic Compounds in the Arctic

    DEFF Research Database (Denmark)

    Lindwall, Frida

    , emitted in order to communicate within and between trophic levels and as protection against biotic and abiotic stresses, or as byproducts. Some BVOCs are very reactive, and when entering the atmosphere they rapidly react with for example hydroxyl radicals and ozone, affecting the oxidative capacity......Emissions of biogenic volatile organic compounds (BVOCs) from arctic ecosystems are scarcely studied and the effect of climate change on BVOC emissions even less so. BVOCs are emitted from all living organisms and play a role for atmospheric chemistry. The major part of BVOCs derives from plants...... dependent and the emissions will increase in a future warmer climate. The aims of this dissertation were to study BVOC emission rates and blends from arctic ecosystems and to reveal the effect of climate change on BVOC emissions from the Arctic. BVOC emissions were measured in ambient and modified...

  8. First Characterisation of Volatile Organic Compounds Emitted by Banana Plants.

    Science.gov (United States)

    Berhal, Chadi; De Clerck, Caroline; Fauconnier, Marie-Laure; Levicek, Carolina; Boullis, Antoine; Kaddes, Amine; Jijakli, Haïssam M; Verheggen, François; Massart, Sébastien

    2017-05-16

    Banana (Musa sp.) ranks fourth in term of worldwide fruit production, and has economical and nutritional key values. The Cavendish cultivars correspond to more than 90% of the production of dessert banana while cooking cultivars are widely consumed locally around the banana belt production area. Many plants, if not all, produce Volatile Organic Compounds (VOCs) as a means of communication with their environment. Although flower and fruit VOCs have been studied for banana, the VOCs produced by the plant have never been identified despite their importance in plant health and development. A volatile collection methodology was optimized to improve the sensitivity and reproducibility of VOCs analysis from banana plants. We have identified 11 VOCs for the Cavendish, mainly (E,E)-α-farnesene (87.90 ± 11.28 ng/μl), methyl salicylate (33.82 ± 14.29) and 6-methyl-5-hepten-2-one (29.60 ± 11.66), and 14 VOCs for the Pacific Plantain cultivar, mainly (Z,E)-α-farnesene (799.64 ± 503.15), (E,E)-α-farnesene (571.24 ± 381.70) and (E) β ocimene (241.76 ± 158.49). This exploratory study paves the way for an in-depth characterisation of VOCs emitted by Musa plants.

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

    Science.gov (United States)

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

    2005-02-01

    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 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.

  10. Toward a Unified View of the Moon's Polar Volatiles from the Lunar Reconnaissance Orbiter

    Science.gov (United States)

    Hayne, Paul

    2016-04-01

    Although the scientific basis for the possibility of water and other volatiles in the cold traps of the lunar polar regions was developed in the 1960's and '70's [1,2], only recently have the data become available to test the theories in detail. Furthermore, comparisons with other planetary bodies, particularly Mercury, have revealed surprising differences that may point to inconsistencies or holes in our understanding of the basic processes involving volatiles on airless bodies [3]. Addressing these gaps in understanding is critical to the future exploration of the Moon, for which water is an important scientific and engineering resource [4]. Launched in 2009, NASA's Lunar Reconnaissance Orbiter (LRO) has been acquiring data from lunar orbit for more than six years. All seven of the remote sensing instruments on the payload have now contributed significantly to advancing understanding of volatiles on the Moon. Here we present results from these investigations, and discuss attempts to synthesize the disparate information to create a self-consistent model for lunar volatiles. In addition to the LRO data, we must take into account results from earlier missions [5,6], ground-based telescopes [7], and sample analyses [8]. The results from these inter-comparisons show that water is likely available in useful quantities, but key additional measurements may be required to resolve remaining uncertainties. [1] Watson, K., Murray, B. C., & Brown, H. (1961), J. Geophys. Res., 66(9), 3033-3045. [2] Arnold, J. R. (1979), J. Geophys. Res. (1978-2012), 84(B10), 5659-5668. [3] Paige, D. A., Siegler, M. A., Harmon, J. K., Neumann, G. A., Mazarico, E. M., Smith, D. E., ... & Solomon, S. C. (2013), Science, 339(6117), 300-303. [4] Hayne, P. O., et al. (2014), Keck Inst. Space Studies Report. [5] Nozette, S., Lichtenberg, C. L., Spudis, P., Bonner, R., Ort, W., Malaret, E., ... & Shoemaker, E. M. (1996), Science, 274(5292), 1495-1498. [6] Pieters, C. M., Goswami, J. N., Clark, R. N

  11. Volatile organic compound emissions from Larrea tridentata (creosotebush)

    Science.gov (United States)

    Jardine, K.; Abrell, L.; Kurc, S. A.; Huxman, T.; Ortega, J.; Guenther, A.

    2010-12-01

    We present results from the CREosote ATmosphere Interactions through Volatile Emissions (CREATIVE 2009) field study in southern Arizona aimed at quantifying emission rates of VOCs from creosotebush (Larrea tridentata) during the summer 2009 monsoon season. This species was chosen because of its vast distribution in North and South American deserts and because its resins have been reported to contain a rich set of volatile organic compounds (VOC). While a variety of ecosystems have been investigated for VOC emissions, deserts remain essentially unstudied, partially because of their low biomass densities and water limitations. However, during the North American monsoon, a pronounced increase in rainfall from an extremely dry June (80 mm) occurs over large areas of the Sonoran desert in the southwestern United States and northwestern Mexico. We observed a strong diurnal pattern of branch emissions and ambient concentrations of an extensive suite of VOCs with maxima in early afternoon. These include VOCs typically observed in forest sites (oxygenated VOCs and volatile isoprenoids) as well as a large number of other compounds, some of which have not been previously described from any plant including 1-chloro-2-methoxy-benzene and isobutyronitrile. Although generally considered to be derived from anthropogenic sources, we observed emissions of aromatic compounds including benzene, and a broad range of phenolics. Dimethyl sulfide emissions from creosotebush were higher than reported from any previously studied plant suggesting that terrestrial ecosystems should be reconsidered as an important source of this climatically important gas. We also present direct, primary emission measurements of isoprene and its apparent oxidation products methyl vinyl ketone, methacrolein, and 3-methyl furan (the later three compounds are typically assumed to form from secondary reactions within the atmosphere), as well as a group of compounds considered to be fatty acid oxidation products

  12. Volatile organic compound emissions from Larrea tridentata (creosotebush

    Directory of Open Access Journals (Sweden)

    A. Guenther

    2010-12-01

    Full Text Available We present results from the CREosote ATmosphere Interactions through Volatile Emissions (CREATIVE 2009 field study in southern Arizona aimed at quantifying emission rates of VOCs from creosotebush (Larrea tridentata during the summer 2009 monsoon season. This species was chosen because of its vast distribution in North and South American deserts and because its resins have been reported to contain a rich set of volatile organic compounds (VOC. While a variety of ecosystems have been investigated for VOC emissions, deserts remain essentially unstudied, partially because of their low biomass densities and water limitations. However, during the North American monsoon, a pronounced increase in rainfall from an extremely dry June (80 mm occurs over large areas of the Sonoran desert in the southwestern United States and northwestern Mexico. We observed a strong diurnal pattern of branch emissions and ambient concentrations of an extensive suite of VOCs with maxima in early afternoon. These include VOCs typically observed in forest sites (oxygenated VOCs and volatile isoprenoids as well as a large number of other compounds, some of which have not been previously described from any plant including 1-chloro-2-methoxy-benzene and isobutyronitrile. Although generally considered to be derived from anthropogenic sources, we observed emissions of aromatic compounds including benzene, and a broad range of phenolics. Dimethyl sulfide emissions from creosotebush were higher than reported from any previously studied plant suggesting that terrestrial ecosystems should be reconsidered as an important source of this climatically important gas. We also present direct, primary emission measurements of isoprene and its apparent oxidation products methyl vinyl ketone, methacrolein, and 3-methyl furan (the later three compounds are typically assumed to form from secondary reactions within the atmosphere, as well as a group of compounds considered to be fatty acid

  13. Extraction optimization and pixel-based chemometric analysis of semi-volatile organic compounds in groundwater

    DEFF Research Database (Denmark)

    Christensen, Peter; Tomasi, Giorgio; Kristensen, Mette

    2017-01-01

    Semi-volatile organic compounds (semi-VOCs) are found in complex mixtures, and at low concentrations in groundwater. Chemical fingerprint analysis of groundwater is therefore challenging, as it is necessary to obtain high enrichment factors for compounds with a wide range of properties. In this s......Semi-volatile organic compounds (semi-VOCs) are found in complex mixtures, and at low concentrations in groundwater. Chemical fingerprint analysis of groundwater is therefore challenging, as it is necessary to obtain high enrichment factors for compounds with a wide range of properties....... In this study, we tested the combination of solid phase extraction (SPE) with dispersive liquid-liquid micro extraction (DLLME), or with stir bar sorptive extraction (SBSE), as an extraction method for semi-VOCs in groundwater. Combining SPE with DLLME or SBSE resulted in better separation of peaks...... in an unresolved complex mixture. SPE-DLLME was chosen as the preferred extraction method. SPE-DLLME covered a larger polarity range (logKo/w 2.0-11.2), had higher extraction efficiency at logKo/w 2.0-3.8 and 5.8-11.2, and was faster compared to SPE-SBSE. SPE-DLLME extraction combined with chemical analysis by gas...

  14. Volatile organic components in laser and electrosurgery plume

    Science.gov (United States)

    Albrecht, Hansjoerg; Hagemann, Roland; Waesche, Wolfgang; Wagner, Guenther; Mueller, Gerhard J.

    1994-02-01

    Volatile organic compound (VOCs) emissions from laser surgery and electrosurgery were evaluated using a multisorbent sampler and capillary gas chromatograph system (GC). The experiments were carried out by vaporization of different tissues (liver, muscle, skin) under standardized conditions by use of CO2 and Nd:YAG lasers. As comparison the VOCs produced with an electrocauter surgical unit were investigated. With the use of a described sample and analyzer train a mixture of about 150 VOCs has been obtained. Up to now 15 substances have been identified as non-aromatic aldehydes, nitrils and aromatic hydrocarbons. The studies focus on quantitative results for these identified components. By use of the Toluene production the dependence of the emitted concentration on parameters as wavelength, power density, total energy applied, and tissue type can be shown.

  15. [Definition and Control Indicators of Volatile Organic Compounds in China].

    Science.gov (United States)

    Jiang, Mei; Zou, Lan; Li, Xiao-qian; Che, Fei; Zhao, Guo-hua; Li, Gang; Zhang, Guo-ning

    2015-09-01

    Volatile organic compounds (VOCs) are the most complex of a wide range of pollutants that harms human health and ecological environment. However, various countries around the world differ on its definition and control indicators. Its definition, control indicators and monitoring methods of our country and local standards were also different. Based on detailed analysis of the definitions and control indicators of VOCs, the recommendations were proposed: the definition of VOCs should be different according to the different concerns between "air quality management" and "pollution emissions management"; base on different control way from production source, technological process, terminal emission, total discharge control, the control indicators system consists of 10 indicators; to formulate industry VOCs emissions standards, the most effective control way and indicators should be chosen according to characteristics of production process, way of VOCs emissions and possible control measures, etc.

  16. Imaging subsurface geology and volatile organic compound plumes

    International Nuclear Information System (INIS)

    Qualheim, B.J.; Daley, P.F.; Johnson, V.; McPherrin, R.V.; Laguna, G.

    1992-03-01

    Lawrence Livermore National Laboratory (LLNL) (Fig. 1) is in the final stages of the Superfund decisionmaking process for site remediation and restoration. In the process of characterizing the subsurface of the LLNL site, we have developed unique methods of collecting, storing, retrieving, and imaging geologic and chemical data from more than 350 drill holes. The lateral and vertical continuity of subsurface paleostream channels were mapped for the entire LLNL site using geologic descriptions from core samples, cuttings, and interpretations from geophysical logs. A computer-aided design and drafting program, SLICE, written at LLNL, was used to create two-dimensional maps of subsurface sediments, and state-of-the-art software produced three-dimensional images of the volatile organic compound (VOC) plumes using data from water and core fluid analyses

  17. Detection of volatile organic compounds using surface enhanced Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-22

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

    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.

  19. Volatile organic components in the Skylab 4 spacecraft atmosphere

    Science.gov (United States)

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

    1975-01-01

    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.

  20. Volatile organic compound emission profiles of four common arctic plants

    DEFF Research Database (Denmark)

    Vedel-Petersen, Ida; Schollert, Michelle; Nymand, Josephine

    2015-01-01

    The biogenic volatile organic compound (BVOC) emissions from plants impact atmosphere and climate. The species-specific emissions, and thereby the atmospheric impact, of many plant species are still unknown. Knowledge of BVOC emission from arctic plants is particularly limited. The vast area...... and relatively high leaf temperature give the Arctic potential for emissions that cannot be neglected. This field study aimed to elucidate the BVOC emission profiles for four common arctic plant species in their natural environment during the growing season. BVOCs were sampled from aboveground parts of Empetrum...... emitted the least BVOCs, dominated by sesquiterpenes (SQTs) and non-isoprenoid BVOCs. The Salix spp. emitted the most, dominated by isoprene. The emissions of B. nana were composed of about two-thirds non-isoprenoid BVOCs, with moderate amounts of monoterpenes (MTs) and SQTs. The total B. nana emissions...

  1. Investigation of michelson interferometer for volatile organic compound sensor

    International Nuclear Information System (INIS)

    Marzuarman; Rivai, Muhammad; Sardjono, Tri Arief; Purwanto, Djoko

    2017-01-01

    The sensor device is required to monitor harmful gases in the environments and industries. Many volatile organic compounds adsorbed on the sensor material will result in changes of the optical properties including the refractive index and the film thickness. This study designed and realized a vapor detection device using the principle of Michelson Interferometer. The laser light beamed with a wavelength of 620 nm was divided by using a beam splitter. Interference occurredwhen the two separated lights were recombined. The phase difference between the two beams determined whether the interference would destruct or construct each other to produce the curved fringes. The vapor samples used in these experiments were ethanol and benzene. The results showed that the ethanol concentration of 1611-32210 ppm produced a fringe shift of 197 pixels, while the concentration of benzene of 964-19290 ppm produced a fringe shift of 273 pixels. (paper)

  2. Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.

    Science.gov (United States)

    Marcillo, Andrea; Jakimovska, Viktorija; Widdig, Anja; Birkemeyer, Claudia

    2017-09-08

    Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Crude glycerol combustion: Particulate, acrolein, and other volatile organic emissions

    KAUST Repository

    Steinmetz, Scott

    2013-01-01

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and fossil fuel substitution. However, challenges to the use of crude glycerol as a boiler fuel include its low energy density, high viscosity, and high autoignition temperature. We have previously shown that a refractory-lined, high swirl burner can overcome challenges related to flame ignition and stability. However, critical issues related to ash behavior and the possible formation of acrolein remained. The work presented here indicates that the presence of dissolved catalysts used during the esterification and transesterification processes results in extremely large amounts of inorganic species in the crude glycerol. For the fuels examined here, the result is a submicron fly ash comprised primarily of sodium carbonates, phosphates, and sulfates. These particles report to a well-developed accumulation mode (0.3-0.7 μm diameter), indicating extensive ash vaporization and particle formation via nucleation, condensation, and coagulation. Particle mass emissions were between 2 and 4 g/m3. These results indicate that glycerol containing soluble catalyst is not suitable as a boiler fuel. Fortunately, process improvements are currently addressing this issue. Additionally, acrolein is of concern due to its toxicity, and is known to be formed from the low temperature thermal decomposition of glycerol. Currently, there is no known reliable method for measuring acrolein in sources. Acrolein and emissions of other volatile organic compounds were characterized through the use of a SUMMA canister-based sampling method followed by GC-MS analysis designed for ambient measurements. Results indicate crude glycerol combustion produces relatively small amounts of acrolein (∼15 ppbv) and other volatile organic

  4. Emission of the main biogenic volatile organic compounds in France

    International Nuclear Information System (INIS)

    Luchetta, L.; Simon, V.; Torres, L.

    2000-01-01

    An estimation of biogenic emissions of the main non-methanic Volatile Organic Compounds (VOCs) due to the forest cover in France has been realized. 32 species representing 98% of French forest have been considered for the estimation. The latter dealt on a net made of 93 irregular spatial grids (Departments) with an average size of 75 km x 75 km. We assigned emission rates and foliar biomass densities specific to each of the 32 species. The environmental variables (temperature, light intensity) have been collected for the whole of French Departments. A special effort was extended so as to use ''Guenther's'' calculation algorithms, and specific emitting factors to species growing in France or in bordering countries. Along the way of the five years (1994-1998) of the study we have calculated the yearly mean of isoprene, mono-terpenes and Other Volatile Organic Compounds (OVOCs) emissions on the scale of the French Departments. At the national level isoprene emission is reckoned at 457 kt yr -1 and represents nearly 49% of the total emission, whereas mono-terpenes with 350 kt yr -1 and OVOCs with 129 kt yr -1 represent respectively 37% and 14% of the total. The yearly biogenic emission of VOCs in France represents virtually half the anthropic source. However in some regions (Mediterranean area) natural emissions can widely exceed anthropic emissions during certain periods. Let's note the whole of our results remains tinged with a great uncertainty because the estimations carried out are presented with correction factors that can reach values comprised between 4 and 7. (author)

  5. Volatile organic compound ratios as probes of halogen atom chemistry in the Arctic

    Directory of Open Access Journals (Sweden)

    P. B. Shepson

    2008-03-01

    Full Text Available Volatile organic compound concentration ratios can be used as indicators of halogen chemistry that occurs during ozone depletion events in the Arctic during spring. Here we use a combination of modeling and measurements of [acetone]/[propanal] as an indicator of bromine chemistry, and [isobutane]/[n-butane] and [methyl ethyl ketone]/[n-butane] are used to study the extent of chlorine chemistry during four ozone depletion events during the Polar Sunrise Experiment of 1995. Using a 0-D photochemistry model in which the input of halogen atoms is controlled and varied, the approximate ratio of [Br]/[Cl] can be estimated for each ozone depletion event. It is concluded that there must be an additional source of propanal (likely from the snowpack to correctly simulate the VOC chemistry of the Arctic, and further evidence that the ratio of Br atoms to Cl atoms can vary greatly during ozone depletion events is presented.

  6. Removal of gasoline volatile organic compounds via air biofiltration

    International Nuclear Information System (INIS)

    Miller, R.S.; Saberiyan, A.G.; Esler, C.T.; DeSantis, P.; Andrilenas, J.S.

    1995-01-01

    Volatile organic compounds (VOCs) generated by vapor extraction and air-stripping systems can be biologically treated in an air biofiltration unit. An air biofilter consists of one or more beds of packing material inoculated with heterotrophic microorganisms capable of degrading the organic contaminant of concern. Waste gases and oxygen are passed through the inoculated packing material, where the microorganisms will degrade the contaminant and release CO 2 + H 2 O. Based on data obtained from a treatability study, a full-scale unit was designed and constructed to be used for treating gasoline vapors generated by a vapor-extraction and groundwater-treatment system at a site in California. The unit is composed of two cylindrical reactors with a total packing volume of 3 m 3 . Both reactors are packed with sphagnum moss and inoculated with hydrocarbon-degrading microorganisms of Pseudomonas and Arthrobacter spp. The two reactors are connected in series for air-flow passage. Parallel lines are used for injection of water, nutrients, and buffer to each reactor. Data collected during the startup program have demonstrated an air biofiltration unit with high organic-vapor-removal efficiency

  7. Boost up carrier mobility for ferroelectric organic transistor memory via buffering interfacial polarization fluctuation.

    Science.gov (United States)

    Sun, Huabin; Wang, Qijing; Li, Yun; Lin, Yen-Fu; Wang, Yu; Yin, Yao; Xu, Yong; Liu, Chuan; Tsukagoshi, Kazuhito; Pan, Lijia; Wang, Xizhang; Hu, Zheng; Shi, Yi

    2014-11-27

    Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm(2) V(-1) s(-1) is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the "reading" and "programming" speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method.

  8. Boost Up Carrier Mobility for Ferroelectric Organic Transistor Memory via Buffering Interfacial Polarization Fluctuation

    Science.gov (United States)

    Sun, Huabin; Wang, Qijing; Li, Yun; Lin, Yen-Fu; Wang, Yu; Yin, Yao; Xu, Yong; Liu, Chuan; Tsukagoshi, Kazuhito; Pan, Lijia; Wang, Xizhang; Hu, Zheng; Shi, Yi

    2014-11-01

    Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm2 V-1 s-1 is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the ``reading'' and ``programming'' speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method.

  9. Chemical oxidation of volatile and semi-volatile organic compounds in soil

    International Nuclear Information System (INIS)

    Gates, D.D.; Siegrist, R.L.; Cline, S.R.

    1995-01-01

    Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 μg/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult

  10. Qualitative analysis of volatile organic compounds on biochar.

    Science.gov (United States)

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

    2011-10-01

    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. Published by Elsevier Ltd.

  11. 78 FR 78726 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...

    Science.gov (United States)

    2013-12-27

    ... request from the Indiana Department of Environmental Management to revise its volatile organic compound... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R05-OAR-2012-0453; FRL-9904-35-Region 5] Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound Emission...

  12. Smelly fumes: volatile-mediated communication between bacteria and other organisms

    NARCIS (Netherlands)

    Weisskopf, Laure; Garbeva, P.V.; Ryu, Choo-Min; Raaijmakers, J.M.

    2016-01-01

    Volatiles are small (<300 Da), smelly molecules emitted by all organisms. They have very diverse roles for the producing organism (e.g., as infochemicals or antimicrobial compounds) and fulfill important ecosystem functions. While the importance of plant volatiles has been recognized for more than

  13. Volatile Organic Compounds: Characteristics, distribution and sources in urban schools

    Science.gov (United States)

    Mishra, Nitika; Bartsch, Jennifer; Ayoko, Godwin A.; Salthammer, Tunga; Morawska, Lidia

    2015-04-01

    Long term exposure to organic pollutants, both inside and outside school buildings may affect children's health and influence their learning performance. Since children spend significant amount of time in school, air quality, especially in classrooms plays a key role in determining the health risks associated with exposure at schools. Within this context, the present study investigated the ambient concentrations of Volatile Organic Compounds (VOCs) in 25 primary schools in Brisbane with the aim to quantify the indoor and outdoor VOCs concentrations, identify VOCs sources and their contribution, and based on these; propose mitigation measures to reduce VOCs exposure in schools. One of the most important findings is the occurrence of indoor sources, indicated by the I/O ratio >1 in 19 schools. Principal Component Analysis with Varimax rotation was used to identify common sources of VOCs and source contribution was calculated using an Absolute Principal Component Scores technique. The result showed that outdoor 47% of VOCs were contributed by petrol vehicle exhaust but the overall cleaning products had the highest contribution of 41% indoors followed by air fresheners and art and craft activities. These findings point to the need for a range of basic precautions during the selection, use and storage of cleaning products and materials to reduce the risk from these sources.

  14. Influence of Sensory Stimulation on Exhaled Volatile Organic Compounds.

    Science.gov (United States)

    Mazzatenta, A; Pokorski, M; Di Tano, A; Cacchio, M; Di Giulio, C

    2016-01-01

    The real-time exhaled volatile organic compounds (VOCs) have been suggested as a new biomarker to detect and monitor physiological processes in the respiratory system. The VOCs profile in exhaled breath reflects the biochemical alterations related to metabolic changes, organ failure, and neuronal activity, which are, at least in part, transmitted via the lungs to the alveolar exhaled breath. Breath analysis has been applied to investigate cancer, lung failure, and neurodegenerative diseases. There are by far no studies on the real-time monitoring of VOCs in sensory stimulation in healthy subjects. Therefore, in this study we investigated the breath parameters and exhaled VOCs in humans during sensory stimulation: smell, hearing, sight, and touch. Responses sensory stimulations were recorded in 12 volunteers using an iAQ-2000 sensor. We found significant effects of sensory stimulation. In particular, olfactory stimulation was the most effective stimulus that elicited the greatest VOCs variations in the exhaled breath. Since the olfactory pathway is distinctly driven by the hypothalamic and limbic circuitry, while other senses project first to the thalamic area and then re-project to other brain areas, the findings suggest the importance of olfaction and chemoreception in the regulation lung gas exchange. VOCs variations during sensory activation may become putative indicators of neural activity.

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

    Science.gov (United States)

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

    2016-09-01

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

  16. Biogenic volatile organic compound emissions from vegetation fires.

    Science.gov (United States)

    Ciccioli, Paolo; Centritto, Mauro; Loreto, Francesco

    2014-08-01

    The aim of this paper was to provide an overview of the current state of the art on research into the emission of biogenic volatile organic compounds (BVOCs) from vegetation fires. Significant amounts of VOCs are emitted from vegetation fires, including several reactive compounds, the majority belonging to the isoprenoid family, which rapidly disappear in the plume to yield pollutants such as secondary organic aerosol and ozone. This makes determination of fire-induced BVOC emission difficult, particularly in areas where the ratio between VOCs and anthropogenic NOx is favourable to the production of ozone, such as Mediterranean areas and highly anthropic temperate (and fire-prone) regions of the Earth. Fire emissions affecting relatively pristine areas, such as the Amazon and the African savannah, are representative of emissions of undisturbed plant communities. We also examined expected BVOC emissions at different stages of fire development and combustion, from drying to flaming, and from heatwaves coming into contact with unburned vegetation at the edge of fires. We conclude that forest fires may dramatically change emission factors and the profile of emitted BVOCs, thereby influencing the chemistry and physics of the atmosphere, the physiology of plants and the evolution of plant communities within the ecosystem. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  17. Compositing water samples for analysis of volatile organic compounds

    Science.gov (United States)

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

    2000-01-01

    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

  18. Datasets used in the manuscript titled "Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol"

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset documents that all of the data used in the manuscript "Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic...

  19. Volatility

    Directory of Open Access Journals (Sweden)

    María Sánchez

    2016-11-01

    Full Text Available The action consists of moving with small kicks a tin of cola refresh -without Brand-from a point of the city up to other one. During the path I avoid bollards, the slope differences between sidewalks, pedestrians, parked motorcycles, etc. Volatility wants to say exactly that the money is getting lost. That the money is losing by gentlemen and by ladies who are neither financial sharks, nor big businessmen… or similarly, but ingenuous people, as you or as me, who walk down the street.

  20. Advances in Biodegradation of Multiple Volatile Organic Compounds

    Science.gov (United States)

    Zhang, M.; Yoshikawa, M.

    2017-12-01

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

  1. [Determination of volatile organic compounds in atmospheric environment].

    Science.gov (United States)

    Chen, H W; Li, G K; Li, H; Zhang, Z X; Wang, B G; Li, T; Luo, H K

    2001-11-01

    It is well known that volatile organic compounds (VOCs) are the main photochemical pollutants and ozone precursors of the photochemical smog. Investigation of photochemical pollution in the ambient air must focus on VOCs, but the concentration of VOCs in ambient air is in a very low level (10(-9)-10(-12), volume fraction), so there are difficulties in the determination of VOCs. In this work, based on the TO14A and TO15 methods recommended by the Environmental Protection Agency of United States, an improved method for the determination of fifty-six VOCs, mainly O3 precursors, in atmospheric environment was developed. Operating conditions of VOCs preconcentrator, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were optimized. Air sample was first frozen by liquid nitrogen, and then H2O and CO2 were eliminated in the VOCs preconcentrator. The preconcentrated VOCs sample was injected to GC and detected by MS or hydrogen flame ionization detector (FID). The C2-C10 hydrocarbons were separated effectively in capillary columns under the high concentration of CO2. The detection limits were 0.1 microgram.m-3 and the relative standard deviations were in the range from 2.57% to 9.82%. This method has been used for the determination of VOCs in real samples. The results were satisfactory.

  2. Emission of volatile organic compounds from Portuguese eucalyptus forests

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, T.V.; Pio, C.A. [Universidade de Aveiro (Portugal). Dept. de Ambiente e Ordenamento

    2001-07-01

    Emission to the atmosphere of volatile organic compounds (VOCs) by Eucalyptus globulus was studied in the laboratory with young specimen, and in the field with adult trees. Eucalyptus emits both monoterpenes and isoprene. The leaves of young trees emit at higher rates than the leaves of adult trees. The emission of isoprene is highly predominant during the day. The emission of isoprene is dependent on temperature and solar radiation. The emission rate follows the Guenther algorithm if a based emission factor of 32 {mu}gg{sub dw} {sup -1}h{sup -1} is used, increasing with temperature, to a maximum at 40{sup o}C. At higher temperatures there is a decrease in the emission rate. The main C{sub 10} emitted is 1,8-cineol. Cineol emissions increase exponentially with temperature, and are also seasonally dependent. Application of the emission algorithm to the Portuguese eucalyptus forests shows that during summer isoprene and monoterpene emissions by eucalyptus are of the same order of anthropogenic VOC production. Furthermore, in certain regions, in the center-north of Portugal, where eucalyptus forests are predominant, isoprene emissions can reach an order of magnitude higher than anthropogenic production of VOCs during daytime periods in July and August. (Author)

  3. Personal exposure to volatile organic compounds in the Czech Republic.

    Science.gov (United States)

    Svecova, Vlasta; Topinka, Jan; Solansky, Ivo; Sram, Radim J

    2012-09-01

    Personal exposures to volatile organic compounds (VOCs) were measured in the three industrial cities in the Czech Republic, Ostrava, Karvina and Havirov, while the city of Prague served as a control in a large-scale molecular epidemiological study identifying the impacts of air pollution on human health. Office workers from Ostrava and city policemen from Karvina, Havirov and Prague were monitored in the winter and summer of 2009. Only adult non-smokers participated in the study (N=160). Radiello-diffusive passive samplers were used to measure the exposure to benzene, toluene, ethylbenzene, meta- plus para-xylene and ortho-xylene (BTEX). All participants completed a personal questionnaire and a time-location-activity diary (TLAD). The average personal BTEX exposure levels in both seasons were 7.2/34.3/4.4/16.1 μg/m(3), respectively. The benzene levels were highest in winter in Karvina, Ostrava and Prague: 8.5, 7.2 and 5.3 μg/m(3), respectively. The personal exposures to BTEX were higher than the corresponding stationary monitoring levels detected in the individual localities (Pfireplace or gas stove, automobile use and being in a restaurant were important predictors for benzene personal exposure. Ostrava's outdoor benzene pollution was a significant factor increasing the exposure of the Ostrava study participants in winter (P<0.05).

  4. Airborne concentrations of volatile organic compounds in neonatal incubators.

    Science.gov (United States)

    Prazad, P; Cortes, D R; Puppala, B L; Donovan, R; Kumar, S; Gulati, A

    2008-08-01

    To identify and quantify airborne volatile organic compounds (VOCs) inside neonatal incubators during various modes of operation within the neonatal intensive care unit (NICU) environment. Air samples were taken from 10 unoccupied incubators in four operational settings along with ambient air samples using air sampling canisters. The samples were analyzed following EPA TO-15 using a Tekmar AutoCan interfaced to Agilent 6890 Gas Chromatograph with a 5973 Mass Spectrometer calibrated for 60 EPA TO-15 method target compounds. Non-target compounds were tentatively identified using mass spectral interpretation and with a mass spectral library created by National Institute for Standards and Technology. Two non-target compounds, 2-heptanone and n-butyl acetate, were found at elevated concentrations inside the incubators compared with ambient room air samples. Increase in temperature and addition of humidity produced further increased concentrations of these compounds. Their identities were verified by mass spectra and relative retention times using authentic standards. They were quantified using vinyl acetate and 2-hexanone as surrogate standards. The emission pattern of these two compounds and background measurements indicate that they originate inside the incubator. There is evidence that exposure to some VOCs may adversely impact the fetal and developing infants' health. Currently, as there is no definitive information available on the effects of acute or chronic low-level exposure to these compounds in neonates, future studies evaluating the health effects of neonatal exposure to these VOCs are needed.

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

    Science.gov (United States)

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

    2011-01-01

    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.

  6. Volatile organic emissions from the distillation and pyrolysis of vegetation

    Science.gov (United States)

    Greenberg, J. P.; Friedli, H.; Guenther, A. B.; Hanson, D.; Harley, P.; Karl, T.

    2006-01-01

    Leaf and woody plant tissue (Pinus ponderosa, Eucalyptus saligna, Quercus gambelli, Saccharum officinarum and Oriza sativa) were heated from 30 to 300°C and volatile organic compound (VOC) emissions were identified and quantified. Major VOC emissions were mostly oxygenated and included acetic acid, furylaldehyde, acetol, pyrazine, terpenes, 2,3-butadione, phenol and methanol, as well as smaller emissions of furan, acetone, acetaldehyde, acetonitrile and benzaldehyde. Total VOC emissions from distillation and pyrolysis were on the order of 10 gC/kgC dry weight of vegetation, as much as 33% and 44% of CO2 emissions (gC(VOC)/gC(CO2)) measured during the same experiments, in air and nitrogen atmospheres, respectively. The emissions are similar in identity and quantity to those from smoldering combustion of woody tissue and of different character than those evolved during flaming combustion. VOC emissions from the distillation of pools and endothermic pyrolysis under low turbulence conditions may produce flammable concentrations near leaves and may facilitate the propagation of wildfires. VOC emissions from charcoal production are also related to distillation and pyrolysis; the emissions of the highly reactive VOCs from production are as large as the carbon monoxide emissions.

  7. Predicting flammability of gas mixtures containing volatile organic compounds

    International Nuclear Information System (INIS)

    Liekhus, K.

    1997-01-01

    One requirement regarding the transportation of transuranic (TRU) radioactive waste containers currently limits the total concentration of potentially flammable volatile organic compounds (VOCs) and flammable gases in the headspace of the waste container. Typical VOCs observed in the drums include aromatic hydrocarbons, ketones, alcohols, cyclohexane, as well as chlorinated hydrocarbons (alkanes and alkenes). Flammable gases, such as hydrogen and methane, may be generated in the containers by radiation-induced decomposition (radiolysis) of water and hydrocarbon waste forms. An experimental program was initiated to identify an accurate means for predicting flammability for gas mixtures containing one or more of the following species: hydrogen, carbon tetrachloride, 1,2-dichloroethane, toluene, or 2-butanone. The lower flammability limits (LFL) of gas mixtures containing equimolar quantity for each species were determined in a 19-liter laboratory flammability chamber using a strong spark ignition source. The group factor contribution method was determined to be more accurate than the LeChatelier method for estimating the LFL for these gas mixtures

  8. Volatile organic emissions from the distillation and pyrolysis of vegetation

    Directory of Open Access Journals (Sweden)

    J. P. Greenberg

    2006-01-01

    Full Text Available Leaf and woody plant tissue (Pinus ponderosa, Eucalyptus saligna, Quercus gambelli, Saccharum officinarum and Oriza sativa were heated from 30 to 300°C and volatile organic compound (VOC emissions were identified and quantified. Major VOC emissions were mostly oxygenated and included acetic acid, furylaldehyde, acetol, pyrazine, terpenes, 2,3-butadione, phenol and methanol, as well as smaller emissions of furan, acetone, acetaldehyde, acetonitrile and benzaldehyde. Total VOC emissions from distillation and pyrolysis were on the order of 10 gC/kgC dry weight of vegetation, as much as 33% and 44% of CO2 emissions (gC(VOC/gC(CO2 measured during the same experiments, in air and nitrogen atmospheres, respectively. The emissions are similar in identity and quantity to those from smoldering combustion of woody tissue and of different character than those evolved during flaming combustion. VOC emissions from the distillation of pools and endothermic pyrolysis under low turbulence conditions may produce flammable concentrations near leaves and may facilitate the propagation of wildfires. VOC emissions from charcoal production are also related to distillation and pyrolysis; the emissions of the highly reactive VOCs from production are as large as the carbon monoxide emissions.

  9. Volatile organic compounds in the atmosphere of Mexico City

    Science.gov (United States)

    Garzón, Jessica P.; Huertas, José I.; Magaña, Miguel; Huertas, María E.; Cárdenas, Beatriz; Watanabe, Takuro; Maeda, Tsuneaki; Wakamatsu, Shinji; Blanco, Salvador

    2015-10-01

    The Mexico City Metropolitan Area (MCMA) is one of the most polluted megacities in North America. Therefore, it is an excellent benchmark city to understand atmospheric chemistry and to implement pilot countermeasures. Air quality in the MCMA is not within acceptable levels, mainly due to high ground levels of ozone (O3). Tropospheric O3 is a secondary pollutant formed from the oxidation of volatile organic compounds (VOCs) in the presence of nitrogen oxides and sunlight. To gain a better understanding of O3 formation in megacities, evaluate the effectiveness of already-implemented countermeasures, and identify new cost-effective alternatives to reduce tropospheric O3 concentrations, researchers and environmental authorities require updated concentrations for a broader range of VOCs. Moreover, in an effort to protect human health and the environment, it is important to understand which VOCs exceed reference safe values or most contribute to O3 formation, as well as to identify the most probable emission sources of those VOCs. In this work, 64 VOCs, including 36 toxic VOCs, were measured at four sites in the MCMA during 2011-2012. VOCs related to liquefied petroleum gas leakages exhibited the highest concentrations. Toxic VOCs with the highest average concentrations were acetone and ethanol. The toxic VOC benzene represented the highest risk to Mexican citizens, and toluene contributed the most to O3 formation. Correlation analysis indicated that the measured VOCs come from vehicular emissions and solvent-related industrial sources.

  10. Remediation of ground water containing volatile organic compounds and tritium

    International Nuclear Information System (INIS)

    Shukla, S.N.; Folsom, E.N.

    1994-03-01

    The Trailer 5475 (T-5475) East Taxi Strip Area at Lawrence Livermore National Laboratory (LLNL), Livermore, California was used as a taxi strip by the US Navy to taxi airplanes to the runway from 1942 to 1947. Solvents were used in some unpaved areas adjacent to the East Taxi Strip for cleaning airplanes. From 1953 through 1976, the area was used to store and treat liquid waste. From 1962 to 1976 ponds were constructed and used for evaporation of liquid waste. As a result, the ground water in this area contains volatile organic compounds (VOCs) and tritium. The ground water in this area is also known to contain hexavalent chromium that is probably naturally occurring. Therefore, LLNL has proposed ''pump-and-treat'' technology above grade in a completely closed loop system. The facility will be designed to remove the VOCs and hexavalent chromium, if any, from the ground water, and the treated ground water containing tritium will be reinjected where it will decay naturally in the subsurface. Ground water containing tritium will be reinjected into areas with equal or higher tritium concentrations to comply with California regulations

  11. Constituents of volatile organic compounds of evaporating essential oil

    Science.gov (United States)

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

    2009-12-01

    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.

  12. Biogenic volatile organic compound (VOC) emissions from forests in Finland

    International Nuclear Information System (INIS)

    Lindfors, V.; Laurila, T.

    2000-01-01

    We present model estimates of biogenic volatile organic compound (VOC) emissions from the forests in Finland. The emissions were calculated for the years 1995-1997 using the measured isoprene and monoterpene emission factors of boreal tree species together with detailed satellite land cover information and meteorological data. The three-year average emission is 319 kilotonnes per annum, which is significantly higher than the estimated annual anthropogenic VOC emissions of 193 kilotonnes. The biogenic emissions of the Finnish forests are dominated by monoterpenes, which contribute approximately 45% of the annual total. The main isoprene emitter is the Norway spruce (Picea abies) due to its high foliar biomass density. Compared to the monoterpenes, however, the total isoprene emissions are very low, contributing only about 7% of the annual forest VOC emissions. The isoprene emissions are more sensitive to the meteorological conditions than the monoterpene emissions, but the progress of the thermal growing season is clearly reflected in all biogenic emission fluxes. The biogenic emission densities in northern Finland are approximately half of the emissions in the southern parts of the country. (orig.)

  13. Emission and role of biogenic volatile organic compounds in biosphere

    International Nuclear Information System (INIS)

    Saleem, A.R.

    2013-01-01

    Plants are an essential part of the biosphere. Under the influence of climate change, plants respond in multiple ways within the ecosystem. One such way is the release of assimilated carbon back to the atmosphere in form of biogenic volatile organic compounds (BVOCs), which are produced by plants and are involved in plant growth, reproduction, defense and other . These compounds are emitted from vegetation into the atmosphere under different environmental situations. Plants produce an extensive range of BVOCs, including isoprenoids, sequisterpenes, aldehydes, alcohols and terpenes in different tissues above and below the ground. The emission rates vary with various environmental conditions and the plant growth stage in its life span.BVOCs are released under biotic and abiotic stress changes, like heat, drought, land-use changes, higher atmospheric CO concentrations, increased UV radiation and insect or disease attack. Plants emit BVOCs in atmosphere in order to avoid stress, and adapt to harsh circumstances. These compounds also have a significant role in plant-plant interaction, communication and competition. BVOCs have the ability to alter atmospheric chemistry; they readily react with atmospheric pollutant gases under high temperature and form tropospheric ozone, which is a potent air pollutant for global warming and disease occurrence. BVOCs may be a cause of photochemical smog and increase the stay of other GHGs in the atmosphere. Therefore, further study is required to assess the behavior of BVOCs in the biosphere as well as the atmosphere. (author)

  14. Volatile organic compounds adsorption using different types of adsorbent

    Directory of Open Access Journals (Sweden)

    Pimanmes Chanayotha

    2014-09-01

    Full Text Available Adsorbents were synthesized from coconut shell, coal and coke by pyrolysis followed by chemical activation process. These synthesized materials were used as adsorbents in adsorption test to determine the amount of volatile organic compounds (VOCs namely, 2-Hydroxyethyl methacrylate (HEMA, Octamethylcyclotetrasiloxane and Alkanes standard solution (C8-C20. The adsorption capacities of both synthesized adsorbents and commercial grade adsorbents (Carbotrap™ B and Carbotrap™ C were also compared. It was found that adsorbent A402, which was produced from coconut shell, activated with 40% (wt. potassium hydroxide and at activating temperature of 800°C for 1 hr, could adsorb higher amount of both HEMA and Octamethylcyclotetrasiloxane than other synthesized adsorbents. The maximum adsorption capacity of adsorbent A402 in adsorbing HEMA and Octamethylcyclotetrasiloxane were 77.87% and 50.82% respectively. These adsorption capabilities were 79.73% and 70.07% of the adsorption capacity of the commercial adsorbent Carbotrap™ B respectively. All three types of the synthesized adsorbent (A402, C302, C402 showed the capability to adsorb alkanes standard solution through the range of C8-C20 . However, their adsorption capacities were high in a specific range of C10-C11. The result from the isotherm plot was indicated that surface adsorption of synthesized adsorbent was isotherm type I while the surface adsorption of commercial adsorbent was isotherm type III.

  15. Chemically-Resolved Volatility Measurements of Organic Aerosol from Different Sources

    Science.gov (United States)

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

    2009-04-01

    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.

  16. Volatile organic compounds emissions from gasoline and diesel powered vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Mugica, V [Universidad Autonoma Metropolitana, Mexico, D.F. (Mexico); Vega, E; Sanchez, G; Reyes, E; Arriaga, J. L [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Chow, J; Watson, J; Egami, R [Desert Research Institute, Reno, NV (United States)

    2001-01-01

    In this research, volatile organic compound emissions were characterized from gasoline and diesel vehicles. Sampling campaigns in the Metropolitan Area of Mexico City were designed and carried out in tunnels, crossroads, and truck and bus terminals. The samples were analyzed with gas chromatography getting more than 250 different compounds, being more or less 60 of them the 80% of all the emissions. The most abundant are the two carbon compounds, as a result of the combustion, and compounds related to fuels compositions, like isopentane, xylenes, toluene among others. The profiles obtained in tunnels and crossroads were very similar with the exception of the 3 and 4 carbon compounds, which were found in bigger proportion in the profiles at crossroads. This may probably be due to the blend with the ambient air. The profiles corresponding to trucks and buses have a smaller content of two carbon compounds and a bigger content of xylenes, toluene and ethylbenzene. The variations in the proportions of the compounds allow differentiating the profiles of vehicles using gasoline and diesel. [Spanish] En este trabajo se caracterizaron las emisiones de compuestos organicos volatiles provenientes de vehiculos a gasolina y a diesel. Para ello, se disenaron diversas campanas de muestreo en la zona Metropolitana de la Ciudad de Mexico, en tuneles, cruceros y estaciones de camiones de carga y autobuses. Las muestras se analizaron con cromatografia, de gases obteniendose mas de 250 compuestos distintos, de los cuales aproximadamente 60 corresponden a mas del 80% de las emisiones. Los compuestos mas abundantes son los de dos carbonos, resultado de la combustion, y 4 carbonos que se encontraron en mayor proporcion en los perfiles de cruceros, lo cual se debe probablemente a la mezcla con el aire ambiente. Los perfiles correspondientes a camiones de carga y autobuses tienen un menor contenido de compuestos de dos carbonos y un mayor contenido de xilenos, tolueno y etilbenceno. Estas

  17. Source apportionment of volatile organic compounds measured in Edmonton, Alberta

    Science.gov (United States)

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

    2013-12-01

    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 μg m-3. The average total VOC mass concentration at the Central site was 65 μg 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

  18. Assessing Emissions of Volatile Organic Componds from Landfills Gas

    Directory of Open Access Journals (Sweden)

    Fahime Khademi

    2016-01-01

    Full Text Available Background: Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is composed of 40–45 vol% CO2, 55–65 vol% CH4, and about 1% non-methaneVOCs, and non-methane volatile organic compounds. Emission rates are used to evaluate the compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA. BTEX comounds affect the air quality and may be harmful to human health. Benzene, toluene, ethylbenzene and xylene isomers that are generally called BTEX compounds are the most abundant VOCs in biogas. Methods: Sampling of VOCs in biogas vents was operated passively or with Tedlar bags. 20 samples were collected from 40 wells of old and new biogas sites of Shiraz’ landfill. Immediately after sampling, the samples were transferred to the laboratory. Analysis of the samples was performed with GC-MS. Results: The results showed that in the collection of the old and new biogas sites, the highest concentration of VOCs was observed in toluene (0.85ppm followed by benzene (0.81ppm, ethylbenzene (0.13ppm and xylene (0.08ppm. Conclusion: The results of the study showed that in all samples, most available compounds in biogas vents were aromatic hydrocarbon compounds.These compounds’ constituents originate from household hazardous waste materials deposited in the landfill or from biological/chemical decomposition processes within the landfill.

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

    Science.gov (United States)

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

    2002-01-01

    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.

  20. variability of volatile organic compounds emitted by seedlings of ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    3-hexen-1-ol, heptanal, (z)- ... previously as volatile semiochemicals involved in plant defense against other sucking insect pests. TZB- ... African pest/pathogen complex and is in conformity with previous studies that maize shows relatively high.

  1. A technique for the measurement of organic aerosol hygroscopicity, oxidation level, and volatility distributions

    Science.gov (United States)

    Cain, Kerrigan P.; Pandis, Spyros N.

    2017-12-01

    Hygroscopicity, oxidation level, and volatility are three crucial properties of organic pollutants. This study assesses the feasibility of a novel measurement and analysis technique to determine these properties and establish their relationship. The proposed experimental setup utilizes a cloud condensation nuclei (CCN) counter to quantify hygroscopic activity, an aerosol mass spectrometer to measure the oxidation level, and a thermodenuder to evaluate the volatility. The setup was first tested with secondary organic aerosol (SOA) formed from the ozonolysis of α-pinene. The results of the first experiments indicated that, for this system, the less volatile SOA contained species that had on average lower O : C ratios and hygroscopicities. In this SOA system, both low- and high-volatility components can have comparable oxidation levels and hygroscopicities. The method developed here can be used to provide valuable insights about the relationships among organic aerosol hygroscopicity, oxidation level, and volatility.

  2. Characterization of polar organics in airborne particulate matter

    Science.gov (United States)

    Yokouchi, Y.; Ambe, Y.

    The methanol-extractable highly polar organics in atmospheric aerosol were characterized using GC-MS. Dicarboxylic acids having 2-16 carbon numbers were detected with a total concentration of 172 ng m -3. Azelaic acid ( C9) was the most abundant diacid and it possibly originated from the ozonolysis of unsaturated carboxylic acids such as oleic acid and linoleic acid, which mainly originate from terrestrial plants. A compound, which was tentatively identified as tetrahydrofuroic acid, contributed to about 10% of the highly polar organics. Other polyfunctional compounds found in the samples included some ketocarboxylic acids and aromatic acids such as phthalic acids, anisic acid and vanillic acid.

  3. Volatile organic compounds and Photobacterium phosphoreum associated with spoilage of modified-atmosphere-packaged raw pork

    DEFF Research Database (Denmark)

    Nieminen, Timo T.; Dalgaard, Paw; Björkroth, Johanna

    2016-01-01

    Accumulation of volatile organic compounds was monitored in association with sensory quality, bacterial concentrations and culture-independent microbial community analyses in raw pork loin and pork collar during storage under high-oxygen modified atmosphere at +4°C. Of the 48 volatile compounds d...

  4. High-performance non-volatile organic ferroelectric memory on banknotes.

    Science.gov (United States)

    Khan, M A; Bhansali, Unnat S; Alshareef, H N

    2012-04-24

    High-performance non-volatile polymer ferroelectric memory are fabricated on banknotes using poly(vinylidene fluoride trifluoroethylene). The devices show excellent performance with high remnant polarization, low operating voltages, low leakage, high mobility, and long retention times. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. High-performance non-volatile organic ferroelectric memory on banknotes

    KAUST Repository

    Khan, Yasser

    2012-03-21

    High-performance non-volatile polymer ferroelectric memory are fabricated on banknotes using poly(vinylidene fluoride trifluoroethylene). The devices show excellent performance with high remnant polarization, low operating voltages, low leakage, high mobility, and long retention times. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Alstrøm, Tommy Sonne; Johnsen, C

    2010-01-01

    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...... 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...

  7. Urinary Volatile Organic Compounds for the Detection of Prostate Cancer.

    Directory of Open Access Journals (Sweden)

    Tanzeela Khalid

    Full Text Available The aim of this work was to investigate volatile organic compounds (VOCs emanating from urine samples to determine whether they can be used to classify samples into those from prostate cancer and non-cancer groups. Participants were men referred for a trans-rectal ultrasound-guided prostate biopsy because of an elevated prostate specific antigen (PSA level or abnormal findings on digital rectal examination. Urine samples were collected from patients with prostate cancer (n = 59 and cancer-free controls (n = 43, on the day of their biopsy, prior to their procedure. VOCs from the headspace of basified urine samples were extracted using solid-phase micro-extraction and analysed by gas chromatography/mass spectrometry. Classifiers were developed using Random Forest (RF and Linear Discriminant Analysis (LDA classification techniques. PSA alone had an accuracy of 62-64% in these samples. A model based on 4 VOCs, 2,6-dimethyl-7-octen-2-ol, pentanal, 3-octanone, and 2-octanone, was marginally more accurate 63-65%. When combined, PSA level and these four VOCs had mean accuracies of 74% and 65%, using RF and LDA, respectively. With repeated double cross-validation, the mean accuracies fell to 71% and 65%, using RF and LDA, respectively. Results from VOC profiling of urine headspace are encouraging and suggest that there are other metabolomic avenues worth exploring which could help improve the stratification of men at risk of prostate cancer. This study also adds to our knowledge on the profile of compounds found in basified urine, from controls and cancer patients, which is useful information for future studies comparing the urine from patients with other disease states.

  8. Transport of volatile organic compounds across the capillary fringe

    Science.gov (United States)

    McCarthy, Kathleen A.; Johnson, Richard L.

    1993-01-01

    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.

  9. Passive remediation of chlorinated volatile organic compounds using barometric pumping

    International Nuclear Information System (INIS)

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

    1993-01-01

    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)

  10. Urinary Volatile Organic Compounds for the Detection of Prostate Cancer.

    Science.gov (United States)

    Khalid, Tanzeela; Aggio, Raphael; White, Paul; De Lacy Costello, Ben; Persad, Raj; Al-Kateb, Huda; Jones, Peter; Probert, Chris S; Ratcliffe, Norman

    2015-01-01

    The aim of this work was to investigate volatile organic compounds (VOCs) emanating from urine samples to determine whether they can be used to classify samples into those from prostate cancer and non-cancer groups. Participants were men referred for a trans-rectal ultrasound-guided prostate biopsy because of an elevated prostate specific antigen (PSA) level or abnormal findings on digital rectal examination. Urine samples were collected from patients with prostate cancer (n = 59) and cancer-free controls (n = 43), on the day of their biopsy, prior to their procedure. VOCs from the headspace of basified urine samples were extracted using solid-phase micro-extraction and analysed by gas chromatography/mass spectrometry. Classifiers were developed using Random Forest (RF) and Linear Discriminant Analysis (LDA) classification techniques. PSA alone had an accuracy of 62-64% in these samples. A model based on 4 VOCs, 2,6-dimethyl-7-octen-2-ol, pentanal, 3-octanone, and 2-octanone, was marginally more accurate 63-65%. When combined, PSA level and these four VOCs had mean accuracies of 74% and 65%, using RF and LDA, respectively. With repeated double cross-validation, the mean accuracies fell to 71% and 65%, using RF and LDA, respectively. Results from VOC profiling of urine headspace are encouraging and suggest that there are other metabolomic avenues worth exploring which could help improve the stratification of men at risk of prostate cancer. This study also adds to our knowledge on the profile of compounds found in basified urine, from controls and cancer patients, which is useful information for future studies comparing the urine from patients with other disease states.

  11. Passive remediation of chlorinated volatile organic compounds using barometric pumping

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

    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).

  12. Diagnosing Tibetan pollutant sources via volatile organic compound observations

    Science.gov (United States)

    Li, Hongyan; He, Qiusheng; Song, Qi; Chen, Laiguo; Song, Yongjia; Wang, Yuhang; Lin, Kui; Xu, Zhencheng; Shao, Min

    2017-10-01

    Atmospheric transport of black carbon (BC) from surrounding areas has been shown to impact the Tibetan environment, and clarifying the geographical source and receptor regions is crucial for providing guidance for mitigation actions. In this study, 10 trace volatile organic compounds (VOCs) sampled across Tibet are chosen as proxies to diagnose source regions and related transport of pollutants to Tibet. The levels of these VOCs in Tibet are higher than those in the Arctic and Antarctic regions but much lower than those observed at many remote and background sites in Asia. The highest VOC level is observed in the eastern region, followed by the southern region and the northern region. A positive matrix factorization (PMF) model found that three factors-industry, biomass burning, and traffic-present different spatial distributions, which indicates that different zones of Tibet are influenced by different VOC sources. The average age of the air masses in the northern and eastern regions is estimated to be 3.5 and 2.8 days using the ratio of toluene to benzene, respectively, which indicates the foreign transport of VOC species to those regions. Back-trajectory analyses show that the Afghanistan-Pakistan-Tajikistan region, Indo-Gangetic Plain (IGP), and Meghalaya-Myanmar region could transport industrial VOCs to different zones of Tibet from west to east. The agricultural bases in northern India could transport biomass burning-related VOCs to the middle-northern and eastern zones of Tibet. High traffic along the unique national roads in Tibet is associated with emissions from local sources and neighboring areas. Our study proposes international joint-control efforts and targeted actions to mitigate the climatic changes and effects associated with VOCs in Tibet, which is a climate sensitive region and an important source of global water.

  13. Global simulation of aromatic volatile organic compounds in the atmosphere

    Science.gov (United States)

    Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

    2015-04-01

    Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho

  14. Exchange of volatile organic compounds in the boreal forest floor

    Science.gov (United States)

    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

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

  16. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds

    NARCIS (Netherlands)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M.; Park, Kyungseok

    2015-01-01

    Abstract Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens

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

    Science.gov (United States)

    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...

  18. 40 CFR 60.542a - Alternate standard for volatile organic compounds.

    Science.gov (United States)

    2010-07-01

    ... Rubber Tire Manufacturing Industry § 60.542a Alternate standard for volatile organic compounds. (a) On... tire processed for each month if the operation uses 25 grams (0.055 lb) or less of VOC per tire...

  19. Factors that influence the volatile organic compound content in human breath

    NARCIS (Netherlands)

    Blanchet, L.; Smolinska, Agnieszka; Baranska, Agnieszka; Tigchelaar-Feenstra, E.; Swertz, M.; Zhernakova, A.; Dallinga, J. W.; Wijmenga, C.; van Schooten, Frederik J.

    Background. Thousands of endogenous and exogenous volatile organic compounds (VOCs) are excreted in each breath. Inflammatory and deviant metabolic processes affect the level of endogeneous VOCs, which can serve as specific biomarkers for clinical diagnosis and disease monitoring. Important issues

  20. Volatile organic compounds in emissions from brown-coal-fired residential stoves

    International Nuclear Information System (INIS)

    Engewald, W.; Knobloch, T.; Efer, J.

    1993-01-01

    Volatile organic compounds were determined in stack-gas emissions from the residential burning of brown-coal briquets using adsorptive enrichment on hydrophobic adsorbents, thermal desorption and capillary-gas chromatographic analysis. 152 compounds were identified and quantified. Quantitative emission factors of the identified individual compounds were determined in relation to the amount of the fuel used. These factors permit assessment of the pollution of the city of Leipzig with volatile organic compounds resulting from the burning of indigenous lignite. (orig.) [de

  1. Method of determining the efficiency of air sampling traps to collect and release volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Cucco, J.A.

    1987-01-01

    A new method is described that facilitates determining the efficiency of air sampling traps to adsorb and thermally desorb volatile organic compounds. A known volume of a liquid standard of volatile organic compounds is vaporized into an air stream, a fraction of which is collected on an air sampling trap. This trap is subsequently thermally desorbed and analyzed using a GC/FID. The efficiency of the trap to adsorb and thermally desorb each compound tested is calculated.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-07

    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

  3. Exposure to volatile organic compounds: Comparison among different transportation modes

    Science.gov (United States)

    Do, Duc Hoai; Van Langenhove, Herman; Chigbo, Stephen Izuchukwu; Amare, Abebech Nuguse; Demeestere, Kristof; Walgraeve, Christophe

    2014-09-01

    The increasing trend of promoting public transportation (bus tram, metro, train) and more environmental friendly and sustainable non fossil-fuel alternatives (walking, cycling etc) as substitutes for auto vehicles brings forward new questions with regard to pollutant levels to which commuters are exposed. In this study, three transportation modes (tram, auto vehicle and bicycle) are studied and concentration levels of 84 volatile organic compounds (VOCs) (hydrocarbons, aromatic hydrocarbons, oxygen containing hydrocarbons, terpenes and halogenated compounds) are measured along a route in the city of Ghent, Belgium. The concentration levels are obtained by active sampling on Tenax TA sorbent tubes followed by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) using deuterated toluene as an internal standard. The median total VOC concentrations for the tram mode (33 μg/m³) is 1.7 times higher than that of the bicycle mode (20 μg/m³) and 1.5 times higher than for the car mode (22 μg/m³). It is found that aromatic hydrocarbons account for a significant proportion in the total VOCs concentration (TVOCs) being as high as 41-57%, 59-72% and 58-72% for the tram, car and bicycle respectively. In all transportation modes, there was a high (r > 0.6) degree of correlation between BTEX compounds, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene. When comparing time weighed average concentrations along a fixed route in Ghent, it is found that commuters using the tram mode experience the highest TVOCs concentration levels. However, next to the concentration level to which commuters are exposed, the physical activity level involving the mode of transportation is important to assess the exposure to toxic VOCs. It is proven that the commuter using a bicycle (4.3 ± 1.5 μg) inhales seven and nine times more benzene compared to the commuter using the car and tram respectively, when the same route is followed.

  4. Effects of trace volatile organic compounds on methane oxidation

    Directory of Open Access Journals (Sweden)

    Wilai Chiemchaisri

    2001-06-01

    Full Text Available The effects of volatile organic compounds (VOCs on methane oxidation in landfill cover soils were examined. The batch experiments were conducted using single and mixed VOCs, such as, dichloromethane (DCM, trichloroethylene (TCE, tetrachloroethylene (PCE, and benzene. The results from all combinations showed a decrease in methane oxidation rate with increase in VOC concentrations. Moreover, inhibition effects of TCE and DCM were found higher than benzene and PCE. The reduction of methane oxidation by benzene and PCE could be attributed to the toxicity effect, whereas TCE and DCM were found to exhibit the competitive-inhibition effect. When the soil was mixed with DCM, no methane oxidation was found. Damage to the cell’s internal membrane was found in a methanotrophic culture exposed to VOC gases which is the attachment site of a key enzyme needed for methane oxidationOs efeitos dos compostos orgânicos voláteis (VOCs na oxidação do metano em camadas superficiais do solo. Os experimentos foram conduzidos usando somente VOCs ou mistura do mesmo, como, diclorometano (DCM, tricloroetileno (TCE, tetracloroetileno (PCE, e benzeno. Os resultados de todas as combinações mostraram uma diminuição na taxa da oxidação do metano com aumento nas concentrações de VOC. Além disso, os efeitos da inibição de TCE e de DCM foram mais elevados do que do benzeno e PCE. A redução da oxidação do metano pelo benzeno e PCE poderia ser atribuída ao efeito da toxicidade, visto que TCE e DCM exibiram o efeito de competição-inibição. Quando o solo foi misturado com o DCM, nenhuma oxidação do metano foi encontrada. Os danos à membrana interna celular foi observada em uma cultura metanotrófica exposta aos gases de VOC que é o local de ligação de uma enzima chave necessário para a oxidação do metano.

  5. Organic non-volatile memories from ferroelectric phase separated blends

    Science.gov (United States)

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

    2009-03-01

    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.

  6. Volatility of source apportioned wintertime organic aerosol in the city of Athens

    Science.gov (United States)

    Louvaris, Evangelos E.; Florou, Kalliopi; Karnezi, Eleni; Papanastasiou, Dimitrios K.; Gkatzelis, Georgios I.; Pandis, Spyros N.

    2017-06-01

    The volatility distribution of ambient organic aerosol (OA) and its components was measured during the winter of 2013 in the city of Athens combining a thermodenuder (TD) and a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Positive Matrix Factorization (PMF) analysis of both the ambient and the thermodenuder AMS-spectra resulted in a four-factor solution for the OA, namely: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking OA (COA), and oxygenated OA (OOA). The thermograms of the four factors were analyzed and the corresponding volatility distributions were estimated using the volatility basis set (VBS). All four factors included compounds with a wide range of effective volatilities from 10 to less than 10-4 μg m-3 at 298 K. Almost 40% of the HOA consisted of low-volatility organic compounds (LVOCs) with the semi-volatile compounds (SVOCs) representing roughly 30%, while the remaining 30% consisted of extremely low volatility organic compounds (ELVOCs). BBOA was more volatile than the HOA factor on average, with 10% ELVOCs, 40% LVOCs, and 50% SVOCs. 10% of the COA consisted of ELVOCs, another 65% LVOCs, and 50% SVOCs. Finally, the OOA was the least volatile factor and included 40% ELVOCs, 25% LVOCs, and 35% SVOCs. Combining the volatility distributions and the O:C ratios of the various factors, we placed our results in the 2D-VBS analysis framework of Donahue et al. (2012). HOA and BBOA are in the expected region but also include an ELVOC component. COA is in similar range as HOA, but on average is half an order of magnitude more volatile. The OOA in these wintertime conditions had a moderate O:C ratio and included both semi-volatile and extremely low volatility components. The above results are sensitive to the assumed values of the effective vaporization enthalpy and the accommodation coefficient. A reduction of the accommodation coefficient by an order of magnitude or the reduction of the vaporization enthalpy by 20 kJ mol-1

  7. A Simultaneous Analytical Method to Profile Non-Volatile Components with Low Polarity Elucidating Differences Between Tobacco Leaves Using Atmospheric Pressure Chemical Ionization Mass Spectrometry Detection

    Directory of Open Access Journals (Sweden)

    Ishida Naoyuki

    2016-04-01

    Full Text Available A comprehensive analytical method using liquid chromatography atmospheric pressure chemical ionization mass spectrometry detector (LC/APCI-MSD was developed to determine key non-volatile components with low polarity elucidating holistic difference among tobacco leaves. Nonaqueous reversed-phase chromatography (NARPC using organic solvent ensured simultaneous separation of various components with low polarity in tobacco resin. Application of full-scan mode to APCI-MSD hyphenated with NARPC enabled simultaneous detection of numerous intense product ions given by APCI interface. Parameters for data processing to filter, feature and align peaks were adjusted in order to strike a balance between comprehensiveness and reproducibility in analysis. 63 types of components such as solanesols, chlorophylls, phytosterols, triacylglycerols, solanachromene and others were determined on total ion chromatograms according to authentic components, wavelength spectrum and mass spectrum. The whole area of identified entities among the ones detected on total ion chromatogram reached to over 60% and major entities among those identified showed favorable linearity of determination coefficient of over 0.99. The developed method and data processing procedure were therefore considered feasible for subsequent multivariate analysis. Data matrix consisting of a number of entities was then subjected to principal component analysis (PCA and hierarchical clustering analysis. Cultivars of tobacco leaves were distributed far from each cultivar on PCA score plot and each cluster seemed to be characterized by identified non-volatile components with low polarity. While fluecured Virginia (FCV was loaded by solanachromene, phytosterol esters and triacylglycerols, free phytosterols and chlorophylls loaded Burley (BLY and Oriental (ORI respectively. Consequently the whole methodology consisting of comprehensive method and data processing procedure proved useful to determine key

  8. Volatile organic matter emission trade. Pitfalls and chances. Final report

    International Nuclear Information System (INIS)

    Wind, M.H.A.

    2001-01-01

    The aim of this report is to provide policy makers non-specialist information on a system for tradeable emission rights (VER, abbreviated in Dutch) for volatile matter in the Netherlands in order to be able to choose the best trading system. The information is based on an environmental-economical theory of VER and the results of practical experiments, mainly from the USA. 18 refs [nl

  9. Effects of airborne volatile organic compounds on plants

    International Nuclear Information System (INIS)

    Cape, J.N.

    2003-01-01

    Possible adverse effects of VOCs on vegetation in urban areas cannot be rejected. - Routine measurements of volatile organic compounds (VOCs) in air have shown that average concentrations are very much smaller than those used in laboratory experiments designed to study the effects of VOCs on plants. However, maximum hourly concentrations of some VOCs can be 100 times larger than the average, even in rural air. Experimental studies have rarely extended for longer than a few days, so there is little information on potential long-term effects of exposure to small concentrations. This review considers the available evidence for long-term effects, based on laboratory and field data. Previous reviews of the literature from Germany and the USA are cited, prior to an assessment of the effects of individual VOCs. Although hydrocarbons from vehicle exhausts have been implicated in the observed effects on roadside vegetation, the evidence suggests that it is the nitrogen oxides in the exhaust gases that are mostly responsible. There is evidence that aromatic hydrocarbons can be metabolised in plants, although the fate of the metabolites is not known. There is a large literature on the effects of ethylene, because of its role as a plant hormone. Effects have been reported in the field, in response to industrial emissions, and dose-response experiments over several weeks in laboratory studies have clearly identified the potential for effects at ambient concentrations. The main responses are morphological (e.g. epinasty), which may be reversible, and on the development of flowers and fruit. Effects on seed production may be positive or negative, depending on the exposure concentration. Chlorinated hydrocarbons have been identified as potentially harmful to vegetation, but only one long-term experiment has studied dose-response relationships. As for ethylene, the most sensitive indication of effect was on seed production, although long-term accumulation of trichloroacetic acid in

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

    Directory of Open Access Journals (Sweden)

    A. Hodzic

    2010-06-01

    Full Text Available 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 anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to estimate the potential contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic precursors (S/IVOC in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly 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. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (2–4 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. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40–60% of the total measured SOA at the surface during the day and is somewhat larger than that from commonly measured aromatic VOCs, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively

  11. variability of volatile organic compounds emitted by seedlings of ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    , a flame ionisation detector (FID), and a non-polar HP-1 bonded phase fused silica capillary column (50 m×0.32 mm i.d., film thickness 0.52 µm). The oven temperature was maintained at 30 °C for 1 min, and programmed at 5 °C min-1 to 150 ...

  12. Genetic control of organ shape and tissue polarity.

    Directory of Open Access Journals (Sweden)

    Amelia A Green

    2010-11-01

    Full Text Available The mechanisms by which genes control organ shape are poorly understood. In principle, genes may control shape by modifying local rates and/or orientations of deformation. Distinguishing between these possibilities has been difficult because of interactions between patterns, orientations, and mechanical constraints during growth. Here we show how a combination of growth analysis, molecular genetics, and modelling can be used to dissect the factors contributing to shape. Using the Snapdragon (Antirrhinum flower as an example, we show how shape development reflects local rates and orientations of tissue growth that vary spatially and temporally to form a dynamic growth field. This growth field is under the control of several dorsoventral genes that influence flower shape. The action of these genes can be modelled by assuming they modulate specified growth rates parallel or perpendicular to local orientations, established by a few key organisers of tissue polarity. Models in which dorsoventral genes only influence specified growth rates do not fully account for the observed growth fields and shapes. However, the data can be readily explained by a model in which dorsoventral genes also modify organisers of tissue polarity. In particular, genetic control of tissue polarity organisers at ventral petal junctions and distal boundaries allows both the shape and growth field of the flower to be accounted for in wild type and mutants. The results suggest that genetic control of tissue polarity organisers has played a key role in the development and evolution of shape.

  13. Volatile Organic Compounds in the Breath of Oral Squamous Cell Carcinoma Patients: A Pilot Study.

    Science.gov (United States)

    Hartwig, Stefan; Raguse, Jan D; Pfitzner, Dorothee; Preissner, Robert; Paris, Sebastian; Preissner, Saskia

    2017-12-01

    Objective To assess the feasibility of detecting signature volatile organic compounds in the breath of patients with oral squamous cell carcinoma. Study Design Prospective cohort pilot study. Setting University hospital. Subjects and Methods Using gas chromatography and mass spectrometry, emitted volatile organic compounds in the breath of patients before and after curative surgery (n = 10) were compared with those of healthy subjects (n = 4). It was hypothesized that certain volatile organic compounds disappear after surgical therapy. A characteristic signature of these compounds for diseased patients was compiled and validated. Results Breath analyses revealed 125 volatile organic compounds in patients with oral cancer. A signature of 8 compounds that were characteristic for patients with oral cancer could be detected: 3 from this group presented were absent after surgery. Conclusion The presented results confirmed the hypothesis of an absence of cancer-associated volatile organic compounds in the breath after therapy. In this pilot study, we proved the feasibility of this test approach. Further studies should be initiated to establish protocols for usage in a clinical setting.

  14. Adsorption of Volatile Organic Compounds from Aqueous Solution by Granular Activated Carbon in Batch System

    International Nuclear Information System (INIS)

    Zeinali, F.; Ghoreyshi, A. A.; Najafpour, G.

    2011-01-01

    Chlorinated hydrocarbons and aromatics are the major volatile organic compounds that contaminate the ground water and industrial waste waters. The best way to overcome this problem is to recover the dissolved compounds in water. In order to evaluate the potential ability of granular activated carbon for recovery of volatile organic compounds from water, the equilibrium adsorption was investigated. This study deals with the adsorption of dichloromethane as a typical chlorinated volatile organic compound and toluene as the representative of aromatic volatile organic compounds on a commercial granular activated carbon. The adsorption isotherms of these two volatile organic compounds on granular activated carbon were measured at three different temperatures, toluene at 293, 303 and 313 K and dichloromethane at 298, 303 and 313 K within their solubility concentration range in water. The maximum adsorption capacity of dichloromethane and toluene adsorption by granular activated carbon was 4 and 0.2 mol/Kg-1, respectively. The experimental data obtained were correlated with different adsorption isotherm models. The Langmuir model was well adapted to the description of dichloromethane adsorption on granular activated carbon at all three temperatures, while the adsorption of toluene on granular activated carbon was found to be well described by the Langmuir-BET hybrid model at all three temperatures. The heat of adsorption was also calculated based on the thermodynamic equation of Clausius Clapeyron, which indicates the adsorption process is endothermic for both compounds.

  15. Evaluation of indoor and outdoor climate on sites polluted with volatile organic chemicals

    International Nuclear Information System (INIS)

    1993-01-01

    Papers presented at a meeting on indoor and outdoor climates on sites polluted with volatile organic chemicals. The papers deal with the subject of evaporation of organic chemicals on the polluted sites in relation to the influence on indoor and outdoor climates. Themes dealt with are diffusion through soils and transport of pollutants from the soil into buildings. (AB)

  16. Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation

    Science.gov (United States)

    Kacarab, M.; Li, L.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Two surrogate reactive organic gas (ROG) mixtures were developed to create a controlled reactivity environment simulating different urban atmospheres with varying levels of anthropogenic (e.g. Los Angeles reactivity) and biogenic (e.g. Atlanta reactivity) influences. Traditional chamber experiments focus on the oxidation of one or two volatile organic compound (VOC) precursors, allowing the reactivity of the system to be dictated by those compounds. Surrogate ROG mixtures control the overall reactivity of the system, allowing for the incremental aerosol formation from an added VOC to be observed. The surrogate ROG mixtures were developed based on that used to determine maximum incremental reactivity (MIR) scales for O3 formation from VOC precursors in a Los Angeles smog environment. Environmental chamber experiments were designed to highlight the incremental aerosol formation in the simulated environment due to the addition of an added anthropogenic (aromatic) or biogenic (terpene) VOC. All experiments were conducted in the UC Riverside/CE-CERT dual 90m3 environmental chambers. It was found that the aerosol precursors behaved differently under the two altered reactivity conditions, with more incremental aerosol being formed in the anthropogenic ROG system than in the biogenic ROG system. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Data will be presented on aerosol properties (density, volatility, hygroscopicity) and bulk chemical composition in the gas and particle phases (from a SYFT Technologies selected ion flow tube mass spectrometer, SIFT-MS, and Aerodyne high resolution time of flight aerosol mass spectrometer, HR-ToF-AMS, respectively) comparing the two controlled reactivity systems and single precursor VOC/NOx studies. Incremental aerosol yield data at different controlled reactivities provide a novel and valuable insight in the attempt to extrapolate environmental chamber

  17. Volatile organic compounds profile during milk fermentation by Lactobacillus pentosus and correlations between volatiles flavor and carbohydrate metabolism.

    Science.gov (United States)

    Pan, D D; Wu, Z; Peng, T; Zeng, X Q; Li, H

    2014-02-01

    Flavor, as one of the most important properties determining the acceptability and preference of fermented milks, is influenced by compositional and processing factors. In this study, we focused on the volatile organic compounds related to flavor during milk fermentation by Lactobacillus pentosus according to electronic nose analysis. Xylose (1% addition) metabolized by Lb. pentosus strongly affects the flavor of yogurt, with the potent volatile organic compounds of ethanol (3.08%), 2,3-butanedione (7.77%), and acetic acid (22.70%) detected using solid-phase microextraction coupled with gas chromatography-mass spectrometry analysis. Sensoryanalysis also showed skimmed yogurt fermented by Lb. pentosus with 1% xylose had the unique scores of sourness (acetic acid) and butter flavor (2,3-butanedione). Furthermore, α-acetolactate synthase and α-acetolactate decarboxylase in carbohydrate metabolism play important roles in milk fermentation. Under preferable conditions (pH 5.5, 42 °C) for α-acetolactate synthase and α-acetolactate decarboxylase, the relative content of potent flavor compound 2,3-butanedione was 10.13%, which was 2.55% higher than common culture condition (pH 4.5, 37 °C), revealing that xylose metabolized by Lb. pentosus has potential values for the milk product industry, such as the acceptability and preference of fermented milk product. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Nga Lee; Brown, Steven S.; Archibald, Alexander T.; Atlas, Elliot; Cohen, Ronald C.; Crowley, John N.; Day, Douglas A.; Donahue, Neil M.; Fry, Juliane L.; Fuchs, Hendrik; Griffin, Robert J.; Guzman, Marcelo I.; Herrmann, Hartmut; Hodzic, Alma; Iinuma, Yoshiteru; Jimenez, José L.; Kiendler-Scharr, Astrid; Lee, Ben H.; Luecken, Deborah J.; Mao, Jingqiu; McLaren, Robert; Mutzel, Anke; Osthoff, Hans D.; Ouyang, Bin; Picquet-Varrault, Benedicte; Platt, Ulrich; Pye, Havala O. T.; Rudich, Yinon; Schwantes, Rebecca H.; Shiraiwa, Manabu; Stutz, Jochen; Thornton, Joel A.; Tilgner, Andreas; Williams, Brent J.; Zaveri, Rahul A.

    2017-01-01

    Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms, and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere, and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry–climate models.

    This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first half of the review summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

  19. Volatile organic compounds in ventilated critical care patients: a systematic evaluation of cofactors.

    Science.gov (United States)

    Hüppe, Tobias; Lorenz, Dominik; Wachowiak, Mario; Maurer, Felix; Meiser, Andreas; Groesdonk, Heinrich; Fink, Tobias; Sessler, Daniel I; Kreuer, Sascha

    2017-08-22

    Expired gas (exhalome) analysis of ventilated critical ill patients can be used for drug monitoring and biomarker diagnostics. However, it remains unclear to what extent volatile organic compounds are present in gases from intensive care ventilators, gas cylinders, central hospital gas supplies, and ambient air. We therefore systematically evaluated background volatiles in inspired gas and their influence on the exhalome. We used multi-capillary column ion-mobility spectrometry (MCC-IMS) breath analysis in five mechanically ventilated critical care patients, each over a period of 12 h. We also evaluated volatile organic compounds in inspired gas provided by intensive care ventilators, in compressed air and oxygen from the central gas supply and cylinders, and in the ambient air of an intensive care unit. Volatiles detectable in both inspired and exhaled gas with patient-to-inspired gas ratios gas from critical care ventilators, and 34 were from ambient air. Five volatile compounds were identified from the central gas supply, four from compressed air, and 17 from compressed oxygen. We observed seven contaminating volatiles with patient-to-inspired gas ratios gas from central hospital supplies, compressed gas tanks, and ventilators. Accurate assessment of the exhalome in critical care patients thus requires frequent profiling of inspired gases and appropriate normalisation of the expired signals.

  20. Evaluation of Volatilization by Organic Chemicals Residing Below the Soil Surface

    Science.gov (United States)

    Jury, William A.; Russo, David; Streile, Gary; El Abd, Hesham

    1990-01-01

    Although volatile organic compounds located in buried waste repositories or distributed through the unsaturated soil zone have the potential to migrate to the atmosphere by vapor diffusion, little attention has been paid in the past to estimating the importance of volatilization losses. In this paper a screening model is introduced which evaluates the relative volatilization losses of a number of organic compounds under standard soil conditions. The model is an analytic solution to the problem wherein the organic chemical is located at time zero at uniform concentration in a finite layer of soil covered by a layer of soil devoid of chemical. The compound is assumed to move by vapor or liquid diffusion and by mass flow under the influence of steady upward or zero water flow while undergoing first-order degradation and linear equilibrium adsorption. Loss to the atmosphere is governed by vapor diffusion through a stagnant air boundary layer. Calculations are performed on 35 organic compounds in two model soils with properties characteristic of sandy and clayey soil. The model identifies those compounds with high potential for loss during 1 year after incorporation under 100 cm of soil cover and also is used to calculate the minimum soil cover thickness required to reduce volatilization losses to insignificant levels during the lifetime of the compound in the soil. From the latter calculation it was determined that certain compounds may volatilize from deep subsurface locations or even groundwater unless the soil surface is sealed to prevent gas migration.

  1. Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

    Science.gov (United States)

    Rajput, Prashant; Sarin, M M

    2014-05-01

    This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. The role of volatile organic compounds in the assessment of indoor air quality

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Ingegerd [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemistry and Karolinska Inst., Stockholm (Sweden). Inst. of Environmental Medicine

    1999-07-01

    generation were validated by comparing exposure concentrations measured by two independent chemical analytical methods. Comprehensive critical reviews of the existing literature on VOC, supplemented the experiments, focusing on adsorption/desorption in indoor materials, methods of measurement, occurrence in the indoor air, as well as on human health-related sensory effects of VOC in indoor environments. In all, 34 compounds, frequently detected in indoor air, were distinguished as potent for causing human sensory effects. Of these, 13 were recommended for further investigation in human sensory exposure studies, with regard to postulated criteria for non-adverse health effects and possibility of well-controlled quantitative generation. Taken together, it is concluded from the experiments and the literature reviews that present techniques/methods to assess IAQ, presented in the scientific literature, do not show any certain proof of a link between indoor factors, such as VOC or total volatile organic compounds (TVOC), and human sensory or health effects (special cases such as formaldehyde excluded). Nor is there any proof that these factors are irrelevant for the encountered effects. This lack of evidence is merely due to poor study design. Future research on IAQ and adverse health and sensory effects should be extended to include not only the nonreactive VOC, but also, for example, reactive, polar, and SVOC. Appropriate methods of human sensory measurements should be utilized, and certain groups of people with special sensitivity should be distinguished and used in IAQ studies which are characterized by low concentrations.

  3. Sensory irritating potency of some microbial volatile organic compounds (MVOCs) and a mixture of five MVOCs.

    Science.gov (United States)

    Korpi, A; Kasanen, J P; Alarie, Y; Kosma, V M; Pasanen, A L

    1999-01-01

    The authors investigated the ability/potencies of 3 microbial volatile organic compounds and a mixture of 5 microbial volatile organic compounds to cause eye and upper respiratory tract irritation (i.e., sensory irritation), with an animal bioassay. The authors estimated potencies by determining the concentration capable of decreasing the respiratory frequency of mice by 50% (i.e., the RD50 value). The RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 182 mg/m3 (35 ppm), 1359 mg/m3 (256 ppm), and 17586 mg/m3 (3360 ppm), respectively. Recommended indoor air levels calculated from the individual RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 100, 1000, and 13000 microg/m3, respectively-values considerably higher than the reported measured indoor air levels for these compounds. The RD50 value for a mixture of 5 microbial volatile organic compounds was also determined and found to be 3.6 times lower than estimated from the fractional concentrations and the respective RD50s of the individual components. The data support the conclusion that a variety of microbial volatile organic compounds may have some synergistic effects for the sensory irritation response, which constrains the interpretation and application of recommended indoor air levels of individual microbial volatile organic compounds. The results also showed that if a particular component of a mixture was much more potent than the other components, it may dominate the sensory irritation effect. With respect to irritation symptoms reported in moldy houses, the results of this study indicate that the contribution of microbial volatile organic compounds to these symptoms seems less than previously supposed.

  4. Trends in the adsorption of volatile organic compounds in a large-pore metal-organic framework, IRMOF-1.

    Science.gov (United States)

    Luebbers, Matthew T; Wu, Tianjiao; Shen, Lingjuan; Masel, Richard I

    2010-07-06

    Metal-organic frameworks have been proposed as useful sorbents for the capture of a variety of compounds. In this work, inverse gas chromatography (IGC) utilizing micropacked capillary columns was used to probe the adsorption of more than 30 volatile organic compounds (VOCs) on IRMOF-1. In an attempt to study the effect of structural degradation upon VOC adsorption, multiple samples of IRMOF-1 with widely ranging properties were investigated. Trends in the differential enthalpies and equilibrium constants for the adsorption of VOCs were determined on the basis of the molecular properties of the adsorbate and the structural properties of the MOF sample. The results indicate that samples of IRMOF-1 that are affected by a moderate amount of structural degradation interact with adsorbed species more strongly than does a sample with fewer defects, resulting in higher heats of adsorption. Samples of IRMOF-1 with specific surface areas of around 1000 m(2)/g show heats of adsorption for alkanes that are higher than those estimated previously via Monte Carlo calculations. Although the data for nonpolar (and weakly polar) species showed many of the anticipated trends for the interactions with IRMOF-1, the equilibrium behavior of polar VOCs did not correlate well with the molecular properties of the adsorbate (i.e., vapor pressure and deformation polarizability), leaving some uncertainty about the nature of the interaction mechanism. The equilibrium data and the heats of adsorption were found to fit well to a small group of molecular descriptors through the application of the Abraham linear free-energy relationship, thus providing insight into the complex interactions between the MOF structure and the VOC compounds. Hydrogen bonding interactions were determined to be the primary contributors to specific interactions between adsorbates and the MOF surface. Size exclusion also seems to play a role in the adsorption of larger species. These results show that the interaction of

  5. The Photocatalytic Destruction of Volatile Organic Compounds in Water

    Science.gov (United States)

    1991-12-10

    the light emitted is in the 254 rin wavelength range. A UVX Digital Radiometer was used to measure UV light intensity along the length of the UV lamp...the solution remained to <eec the head space free svste, ntac.. *ext, the polarity on p cower source was .allw for gumring in the ocoosite direction and...the float which forced the air along a groove in the float out of the cylinder. The cylinder was then placed on an asbestos pad on top of a magnetic

  6. In Situ Atmospheric Pressure Measurements in the Martian Southern Polar Region: Mars Volatiles and Climate Surveyor Meteorology Package on the Mars Polar Lander

    Science.gov (United States)

    Harri, A.-M.; Polkko, J.; Siili, T.; Crisp, D.

    1998-01-01

    Pressure observations are crucial for the success of the Mars Volatiles and Climate Surveyor (MVACS) Meteorology (MET) package onboard the Mars Polar Lander (MPL), due for launch early next year. The spacecraft is expected to land in December 1999 (L(sub s) = 256 degrees) at a high southern latitude (74 degrees - 78 degrees S). The nominal period of operation is 90 sols but may last up to 210 sols. The MVACS/MET experiment will provide the first in situ observations of atmospheric pressure, temperature, wind, and humidity in the southern hemisphere of Mars and in the polar regions. The martian atmosphere goes through a large-scale atmospheric pressure cycle due to the annual condensation/sublimation of the atmospheric CO2. Pressure also exhibits short period variations associated with dust storms, tides, and other atmospheric events. A series of pressure measurements can hence provide us with information on the large-scale state and dynamics of the atmosphere, including the CO2 and dust cycles as well as local weather phenomena. The measurements can also shed light on the shorter time scale phenomena (e.g., passage of dust devils) and hence be important in contributing to our understanding of mixing and transport of heat, dust, and water vapor.

  7. Sensory and Physiological Effects on Humans of Combined Exposures to Air Temperatures and Volatile Organic Compounds

    DEFF Research Database (Denmark)

    Mølhave, Lars; Liu, Zunyong; Jørgensen, Anne Hempel

    1993-01-01

    Ten healthy humans were exposed to combinations of volatile organic compounds (VOCs) and air temperature (0 mg/m3 and 10 mg/m3 of a mixture of 22 volatile organic compounds and 18, 22 and 26° C). Previously demonstrated effects of VOCs and thermal exposures were replicated. For the first time nasal...... cross-sectional areas and nasal volumes, as measured by acoustic rhinometry, were shown to decrease with decreasing temperature and increasing VOC exposure. Temperature and pollutant exposures affected air quality, the need for more ventilation, skin humidity on the forehead, sweating, acute sensory...... indoor air concentrations of VOCs should depend on room air temperature....

  8. Uncertainty in aerosol hygroscopicity resulting from semi-volatile organic compounds

    Science.gov (United States)

    Goulden, Olivia; Crooks, Matthew; Connolly, Paul

    2018-01-01

    We present a novel method of exploring the effect of uncertainties in aerosol properties on cloud droplet number using existing cloud droplet activation parameterisations. Aerosol properties of a single involatile particle mode are randomly sampled within an uncertainty range and resulting maximum supersaturations and critical diameters calculated using the cloud droplet activation scheme. Hygroscopicity parameters are subsequently derived and the values of the mean and uncertainty are found to be comparable to experimental observations. A recently proposed cloud droplet activation scheme that includes the effects of co-condensation of semi-volatile organic compounds (SVOCs) onto a single lognormal mode of involatile particles is also considered. In addition to the uncertainties associated with the involatile particles, concentrations, volatility distributions and chemical composition of the SVOCs are randomly sampled and hygroscopicity parameters are derived using the cloud droplet activation scheme. The inclusion of SVOCs is found to have a significant effect on the hygroscopicity and contributes a large uncertainty. For non-volatile particles that are effective cloud condensation nuclei, the co-condensation of SVOCs reduces their actual hygroscopicity by approximately 25 %. A new concept of an effective hygroscopicity parameter is introduced that can computationally efficiently simulate the effect of SVOCs on cloud droplet number concentration without direct modelling of the organic compounds. These effective hygroscopicities can be as much as a factor of 2 higher than those of the non-volatile particles onto which the volatile organic compounds condense.

  9. Theoretical development and analytical solutions for transport of volatile organic compounds in dual-porosity soils

    Science.gov (United States)

    Hantush, Mohamed M.; Govindaraju, Rao S.

    2003-08-01

    Predicting the behavior of volatile organic compounds in soils or sediments is necessary for managing their use and designing appropriate remedial systems to eliminate potential threats to the environment, particularly the air and groundwater resources. In this effort, based on continuity of mass flux, we derive a mass flux boundary condition of the third type in terms of physically based mass transfer rate coefficients, describing the resistance to mass inflow of the soil-air interface, and obtain one-dimensional analytical solutions for transport and degradation of volatile organic compounds in semi-infinite structured soils under steady, unsaturated flow conditions. The advective-dispersive mass balance formulation allows for mobile-immobile liquid phase and vapor diffusive mass transfer, with linear equilibrium adsorption and liquid-vapor phase partitioning in the dynamic and stagnant soil regions. The mass transfer rate coefficients of volatile organic chemicals across the soil-air interface are expressed in terms of solute properties and hydrodynamic characteristics of resistive soil and air-boundary layers. The solutions estimate solute vapor flux from soil surface and describe mobile-phase solute concentration as a function of depth in the soil and time. In particular, solutions were derived for: (1) zero-initial concentration in the soil profile subject to a continuous and pulsed source at the soil surface; and (2) depletion from the soil following an initially contaminated soil profile. Sensitivity analysis with respect to different dimensionless parameters is conducted and the effect on solute concentration and vapor flux of such parameters as volatilization mass transfer velocity relative to infiltration, soil Peclet number, biochemical decay, and diffusive mass transfer into the immobile phase, is plotted and the results are discussed. The mass transfer rate coefficients and the analytical solutions are applied to simulate transport of an example

  10. Spin-polarized light-emitting diodes based on organic bipolar spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Vardeny, Zeev Valentine; Nguyen, Tho Duc; Ehrenfreund, Eitan Avraham

    2017-10-25

    Spin-polarized organic light-emitting diodes are provided. Such spin-polarized organic light-emitting diodes incorporate ferromagnetic electrodes and show considerable spin-valve magneto-electroluminescence and magneto-conductivity responses, with voltage and temperature dependencies that originate from the bipolar spin-polarized space charge limited current.

  11. Emission of ozone and organic volatiles from a selection of laser printers and photocopiers.

    Science.gov (United States)

    Tuomi, T; Engström, B; Niemelä, R; Svinhufvud, J; Reijula, K

    2000-08-01

    To estimate the impact of office equipment on the quality of indoor air, the emission of ozone and organic volatiles was measured from one photocopier and four laser printers, three of which operated according to traditional corona discharge technology. The laser printers equipped with traditional technology emitted significant amounts of ozone and formaldehyde. Lesser amounts of other volatile aldehydes were emitted during printing. The photocopier emitted mainly ozone. In a well-ventilated office environment, the amounts encountered here for individual volatiles were within recommended maximum exposure limits for a reasonable density of printers. Because it is not known whether the concentration of irritating volatiles, such as formaldehyde, should be kept lower in an ozone rich environment or not, and because emissions in the immediate vicinity of the printers exceeded recommendations, the authors recommend that laser printers equipped with the traditional corona rods not be placed beside or immediately at the working site of office personnel. This way, ozone concentrations can be kept below recommended maximum exposure limits, provided that the ventilation rate is adequate. Further, it seems that if a reliable quantitative comparison of total organic volatiles prior to and during printing is to be made, the inertness of the sorbent toward ozone should be confirmed.

  12. Polar Organic Compounds in Surface Waters Collected Near Lead-Zinc Mine and Milling Operations in Missouri

    Science.gov (United States)

    Rostad, C. E.; Schmitt, C. J.; Schumacher, J. G.; Leiker, T. J.

    2007-12-01

    Surface-water samples were collected near a lead mine and mill tailings about 70 miles southwest of St. Louis, Missouri, during the summer of 2006. The purpose of this sampling was to determine if polar organic compounds were present that could be a cause of documented negative impacts to biota downstream. Water samples contained relatively high concentrations of dissolved organic carbon for surface waters (greater than 20 mg/L), but were colorless, which precluded naturally occurring aquatic humic or fulvic acids. Previous analysis indicated that samples were devoid of pesticides and acid/base/neutral extractable semi-volatile organic compounds, such as polycyclic aromatic hydrocarbons. After isolation by three different types of solid phase extraction, samples were analyzed by electrospray ionization/mass spectrometry. Polar organic compounds commonly used in the milling process, such as alkyl xanthates, were not found; however, xanthate degradation products were detected. Most of the polar organic compounds identified contained sulfonate groups, which are characteristic of some of the reagents used in the milling process. Sulfonate compounds may have low sorption onto soil or sediments and be mobile in the aqueous environment.

  13. Electrospun Polyurethane Fibers for Absorption of Volatile Organic Compounds from Air

    NARCIS (Netherlands)

    Scholten, E.; Bromberg, L.; Rutledge, G.C.; Hatton, T.A.

    2011-01-01

    Electrospun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis(phenylisocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and

  14. Assessment of volatile organic compound removal by indoor plants-a novel experimental setup

    DEFF Research Database (Denmark)

    Dela Cruz, Majbrit; Müller, Renate; Svensmark, Bo

    2014-01-01

    Indoor plants can remove volatile organic compounds (VOCs) from the air. The majority of knowledge comes from laboratory studies where results cannot directly be transferred to real-life settings. The aim of this study was to develop an experimental test system to assess VOC removal by indoor...

  15. Atomic and molecular physics of plasma-based environmental technologies for abatement of volatile organic compounds

    International Nuclear Information System (INIS)

    Penetrante, B. M.; Hsiao, M. C.; Bardsley, J. N.; Merritt, B. T.; Vogtin, G. E.; Kuthi, A.; Burkhart, C. P.; Bayless, J. R.

    1997-01-01

    Non-thermal plasma techniques represent a new generation of air emission control technology that potentially could treat large-volume emissions containing dilute concentrations of volatile organic compounds. In order to apply non-thermal plasmas in an industrial scale, it is important to establish the electrical power requirements and byproducts of the process.There is a need for reliable data concerning the primary decomposition mechanisms and subsequent chemical kinetics associated with non- thermal plasma processing of volatile organic compounds. There are many basic atomic and molecular physics issues that are essential in evaluating the economic performance of non-thermal plasma reactors. These studies are important in understanding how the input electrical power is dissipated in the plasma and how efficiently it is converted to the production of the plasma species (radicals, ions or electrons) responsible for the decomposition of the volatile organic compounds. This paper will present results from basic experimental and theoretical studies aimed at identifying the reaction mechanisms responsible for the primary decomposition of various types of volatile organic compounds. (authors)

  16. 75 FR 57390 - Approval and Promulgation of Implementation Plans; Alabama: Volatile Organic Compounds

    Science.gov (United States)

    2010-09-21

    ... Environmental Management (ADEM) on March 3, 2010. The revision modifies the definition of ``volatile organic... the VOC definition on the basis that these compounds make a negligible contribution to tropospheric..., 2009, which excludes these compounds from the regulatory VOC definition. This action is being taken...

  17. 40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

    Science.gov (United States)

    2010-07-01

    ... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

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

    Science.gov (United States)

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

    2010-04-01

    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.

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  2. ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

    Science.gov (United States)

    Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

  3. Removal of H2S and volatile organic sulfur compounds by silicone membrane extraction

    NARCIS (Netherlands)

    Manconi, I.; Lens, P.N.L.

    2009-01-01

    BACKGROUND: This study explores an alternative process for the abatement and/or desulfurization of H2S and volatile organic sulfur compounds (VOSC) containing waste streams, which employs a silicone-based membrane to simultaneously remove H2S and VOSC. An extractive membrane reactor allows the

  4. Microbial Volatile Organic Compound Emissions from Stachybotrys chartarum growing on Gypsum Wallboard and Ceiling tile

    Science.gov (United States)

    This study compared seven toxigenic strains of S. chartarum found in water-damaged buildings to characterize the microbial volatile organic compound (MVOC) emissions profile while growing on gypsum wallboard (W) and ceiling tile (C) coupons. The inoculated coupons with their sub...

  5. Analysis of selected volatile organic compounds at background level in South Africa.

    Science.gov (United States)

    Ntsasa, Napo; Tshilongo, James; Lekoto, Goitsemang

    2017-04-01

    Volatile organic compounds (VOC) are measured globally at urban air pollution monitoring and background level at specific locations such as the Cape Point station. The urban pollution monitoring is legislated at government level; however, the background levels are scientific outputs of the World Meteorological Organisation Global Atmospheric Watch program (WMO/GAW). The Cape Point is a key station in the Southern Hemisphere which monitors greenhouse gases and halocarbons, with reported for over the past decade. The Cape Point station does not have the measurement capability VOC's currently. A joint research between the Cape Point station and the National Metrology Institute of South Africa (NMISA) objective is to perform qualitative and quantitative analysis of volatile organic compounds listed in the GAW program. NMISA is responsible for development, maintain and disseminate primary reference gas mixtures which are directly traceable to the International System of Units (SI) The results of some volatile organic compounds which where sampled in high pressure gas cylinders will be presented. The analysis of samples was performed on the gas chromatography with flame ionisation detector and mass selective detector (GC-FID/MSD) with a dedicate cryogenic pre-concentrator system. Keywords: volatile organic compounds, gas chromatography, pre-concentrator

  6. Volatile organic molecules from Fusarium oxysporum strain 21 with nematicidal activity against Meloidogyne incognita

    NARCIS (Netherlands)

    Terra, Willian César; Campos, Vicente Paulo; Martins, Samuel Julio; Costa, Lilian Simara Abreu S.; Silva, da Júlio Carlos Pereira; Barros, Aline Ferreira; Lopez, Liliana Estupiñan; Santos, Thaisa Conrado Nunes; Smant, Geert; Oliveira, Denilson Ferreira

    2018-01-01

    Volatile organic compounds (VOCs) produced by microorganisms are potential alternatives for the development of new nematicides. In a previous study, we identified VOCs produced by Fusarium oxysporum strain 21 (F.o–21). In this study, we tested the eight most abundant VOCs produced by F.o-21 against

  7. MEASUREMENTS OF VOLATILE ORGANIC COMPOUNDS AND PARTICLES DURING APPLICATION OF LATEX PAINT WITH AN AIRLESS SPRAYER

    Science.gov (United States)

    The paper discusses experiments, conducted at EPA's Indoor Air Quality Research House, to measure airborne concentrations of volatile organic compounds (VOCs) and particles during and following the spray-application of latex wall paint. (NOTE: Paint may be applied indoors by a v...

  8. Volatile organic compound emmission rates from mixed deciduous and coniferous foest in Northern Wisconsin, USA

    Science.gov (United States)

    J. G. Isebrands; A. B. Guenther; P. Harley; D. Helmig; L. Klinger; L. Vierling; P. Zimmerman; C. Geron

    1999-01-01

    Biogenic emissions of volatile organic compounds {VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regions of the world to understand regional and global impacts and to implement possible...

  9. ECOS E-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database

    Energy Technology Data Exchange (ETDEWEB)

    Parisien, Lia [The Environmental Council Of The States, Washington, DC (United States)

    2016-01-31

    This final scientific/technical report on the ECOS e-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database provides a disclaimer and acknowledgement, table of contents, executive summary, description of project activities, and briefing/technical presentation link.

  10. Release and uptake of volatile inorganic and organic gases through the snowpack at Niwot Ridge, Colorado

    NARCIS (Netherlands)

    Helmig, D.; Apel, E.; Blake, D.; Ganzeveld, L.N.; Lefer, B.L.; Meinardi, S.; Swanson, A.L.

    2009-01-01

    Whole air drawn from four heights within the high elevation (3,340 m asl), deep, winter snowpack at Niwot Ridge, Colorado, were sampled into stainless steel canisters, and subsequently analyzed by gas chromatography for 51 volatile inorganic and organic gases. Two adjacent plots with similar snow

  11. Treatment of volatile organic contaminants in a vertical flow filter: Relevance of different removal processes

    NARCIS (Netherlands)

    De Biase, C.; Reger, D.; Schmidt, A.; Jechalke, S.; Reiche, N.; Martínez-Lavanchy, P.M.; Rosell, M.; Van Afferden, M.; Maier, U.; Oswald, S.E.; Thullner, M.

    2011-01-01

    Vertical flow filters and vertical flow constructed wetlands are established wastewater treatment systems and have also been proposed for the treatment of contaminated groundwater. This study investigates the removal processes of volatile organic compounds in a pilot-scale vertical flow filter.

  12. Total Oxidation of Model Volatile Organic Compounds over Some Commercial Catalysts

    Czech Academy of Sciences Publication Activity Database

    Matějová, Lenka; Topka, Pavel; Jirátová, Květa; Šolcová, Olga

    2012-01-01

    Roč. 443, NOV 7 (2012), s. 40-49 ISSN 0926-860X R&D Projects: GA MPO FR-TI1/059 Institutional support: RVO:67985858 Keywords : volatile organic compounds * oxidation * ethanol Subject RIV: DM - Solid Waste and Recycling Impact factor: 3.410, year: 2012

  13. Volatile organic acids generated from kerogen during laboratory heating.

    Science.gov (United States)

    Kawamura, K; Tannenbaum, E; Huizinga, B J; Kaplan, I R

    1986-01-01

    Low molecular weight organic acids were studied in the course of pyrolysis experiments (200-400 degrees C, 2-1,000 h) of kerogen (Green River Formation and Monterey Formation) with and without the presence of water and minerals (montmorillonite, illite and calcite). C1-C10 aliphatic acids and benzoic acid were identified in the pyrolysis products of kerogen. Their distribution is characterized by a dominance of acetic acid followed by formic and propionic acids with an even/odd preference in the range of C4-C10. Total concentrations of these acids amounted to 0.3% of initial kerogen, indicating that kerogen has a good potential for producing organic acids. Geochemical implications of these organic acids are; (1) they are possible intermediates from kerogen to natural gas (CO2, H2, CH4, C2H6, etc.) by decarboxylation, and (2) they may be important and potential contributors to the generation of secondary porosity by dissolving minerals.

  14. Optimization of the polar organic chemical integrative sampler for the sampling of acidic and polar herbicides.

    Science.gov (United States)

    Fauvelle, Vincent; Mazzella, Nicolas; Belles, Angel; Moreira, Aurélie; Allan, Ian J; Budzinski, Hélène

    2014-05-01

    This paper presents an optimization of the pharmaceutical Polar Organic Chemical Integrative Sampler (POCIS-200) under controlled laboratory conditions for the sampling of acidic (2,4-dichlorophenoxyacetic acid (2,4-D), acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid, bentazon, dicamba, mesotrione, and metsulfuron) and polar (atrazine, diuron, and desisopropylatrazine) herbicides in water. Indeed, the conventional configuration of the POCIS-200 (46 cm(2) exposure window, 200 mg of Oasis® hydrophilic lipophilic balance (HLB) receiving phase) is not appropriate for the sampling of very polar and acidic compounds because they rapidly reach a thermodynamic equilibrium with the Oasis HLB receiving phase. Thus, we investigated several ways to extend the initial linear accumulation. On the one hand, increasing the mass of sorbent to 600 mg resulted in sampling rates (R s s) twice as high as those observed with 200 mg (e.g., 287 vs. 157 mL day(-1) for acetochlor ESA). Although detection limits could thereby be reduced, most acidic analytes followed a biphasic uptake, proscribing the use of the conventional first-order model and preventing us from estimating time-weighted average concentrations. On the other hand, reducing the exposure window (3.1 vs. 46 cm(2)) allowed linear accumulations of all analytes over 35 days, but R s s were dramatically reduced (e.g., 157 vs. 11 mL day(-1) for acetochlor ESA). Otherwise, the observation of biphasic releases of performance reference compounds (PRC), though mirroring acidic herbicide biphasic uptake, might complicate the implementation of the PRC approach to correct for environmental exposure conditions.

  15. Molecular corridors and parameterizations of volatility in the chemical evolution of organic aerosols

    Directory of Open Access Journals (Sweden)

    Y. Li

    2016-03-01

    Full Text Available The formation and aging of organic aerosols (OA proceed through multiple steps of chemical reaction and mass transport in the gas and particle phases, which is challenging for the interpretation of field measurements and laboratory experiments as well as accurate representation of OA evolution in atmospheric aerosol models. Based on data from over 30 000 compounds, we show that organic compounds with a wide variety of functional groups fall into molecular corridors, characterized by a tight inverse correlation between molar mass and volatility. We developed parameterizations to predict the saturation mass concentration of organic compounds containing oxygen, nitrogen, and sulfur from the elemental composition that can be measured by soft-ionization high-resolution mass spectrometry. Field measurement data from new particle formation events, biomass burning, cloud/fog processing, and indoor environments were mapped into molecular corridors to characterize the chemical nature of the observed OA components. We found that less-oxidized indoor OA are constrained to a corridor of low molar mass and high volatility, whereas highly oxygenated compounds in atmospheric water extend to high molar mass and low volatility. Among the nitrogen- and sulfur-containing compounds identified in atmospheric aerosols, amines tend to exhibit low molar mass and high volatility, whereas organonitrates and organosulfates follow high O : C corridors extending to high molar mass and low volatility. We suggest that the consideration of molar mass and molecular corridors can help to constrain volatility and particle-phase state in the modeling of OA particularly for nitrogen- and sulfur-containing compounds.

  16. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Directory of Open Access Journals (Sweden)

    E. E. Louvaris

    2017-10-01

    Full Text Available A method is developed following the work of Grieshop et al. (2009 for the determination of the organic aerosol (OA volatility distribution combining thermodenuder (TD and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a scanning mobility particle sizer (SMPS. In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60–75 % of the cooking OA (COA at concentrations around 500 µg m−3 consisted of low-volatility organic compounds (LVOCs, 20–30 % of semivolatile organic compounds (SVOCs, and around 10 % of intermediate-volatility organic compounds (IVOCs. The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol−1 and the effective accommodation coefficient was 0.06–0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  17. Sensing of volatile organic compounds by copper phthalocyanine thin films

    Science.gov (United States)

    Ridhi, R.; Saini, G. S. S.; Tripathi, S. K.

    2017-02-01

    Thin films of copper phthalocyanine have been deposited by thermal evaporation technique. We have subsequently exposed these films to the vapours of methanol, ethanol and propanol. Optical absorption, infrared spectra and electrical conductivities of these films before and after exposure to chemical vapours have been recorded in order to study their sensing mechanisms towards organic vapours. These films exhibit maximum sensing response to methanol while low sensitivities of the films towards ethanol and propanol have been observed. The changes in sensitivities have been correlated with presence of carbon groups in the chemical vapours. The effect of different types of electrodes on response-recovery times of the thin film with organic vapours has been studied and compared. The electrodes gap distance affects the sensitivity as well as response-recovery time values of the thin films.

  18. ORGANIC VOLATILE IMPURITIES AND THEIR REGULATORY LIMITS: A PHARMACEUTICL PERSPECTIVE

    OpenAIRE

    VIVEK CHAVDA; JITENDRA PATEL; VISHAL RUPAPARA; MOINUDDIN SONIWALA

    2013-01-01

    Impurities in drug substances and drug products have been important regulatory issues in the Office of Generic Drugs by having significant impact on the approvability of Abbreviated New Drug Application (ANDAs). Organic solvents are commonly used in the pharmaceutical industry as reaction media, in separation and purification of synthesis products and also for cleaning of equipments. As residual solvents are not desirable substances in a final product, different methods for their removal may ...

  19. Volatile compounds from organic and conventional passion fruit (Passiflora edulis F. Flavicarpa pulp

    Directory of Open Access Journals (Sweden)

    Mariana Serrão Macoris

    2011-06-01

    Full Text Available The volatile compositions from organic and conventional passion fruit pulps produced in Brazil were investigated. The pulps were also physicochemically characterized. The volatile compounds from the headspace of the passion fruit pulp were stripped to a Porapak Q trap for 2 hours; they were eluted with 300 µL of dichloromethane, separated by gas chromatography/flame ionisation detection and identified through gas chromatography/mass spectrometry. Both pulps conformed to the requirements of the Brazilian legislation, indicating they were suitable to be industrialized and consumed. A total of 77 compounds were detected in the headspace of the passion fruit pulps - 60 of which were identified, comprising 91% of the total chromatogram area. The major compounds were the following: ethyl butanoate, 52% and 57% of the total relative area of the chromatogram for the organic and conventional passion fruit pulps, respectively; ethyl hexanoate, 22% and 9%, respectively; and hexyl butanoate, 2% and 5%, respectively. The aroma of the organic passion fruit pulp is mainly related to the following volatile compounds: ethyl hexanoate, methyl hexanoate, β-myrcene and D-limonene. The conventional passion fruit pulp presented methyl butanoate, butyl acetate, hexanal, 1-butanol, butyl butanoate, trans-3-hexenyl acetate, cis-3-hexen-1-ol, butyl hexanoate, hexyl butanoate, 3-hexenyl butanoate and 3-hexenyl hexanoate as the main volatile compounds for aroma.

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

    Science.gov (United States)

    Zhang, Lin; Weng, Huan-xin; Chen, Huan-lin; Gao, Cong-jie

    2002-04-01

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

  1. Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory.

    Science.gov (United States)

    Ng, Tse Nga; Schwartz, David E; Lavery, Leah L; Whiting, Gregory L; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

    2012-01-01

    Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic.

  2. Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory

    Science.gov (United States)

    Ng, Tse Nga; Schwartz, David E.; Lavery, Leah L.; Whiting, Gregory L.; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

    2012-01-01

    Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic. PMID:22900143

  3. Electrochemical behavior of uranyl in anhydrous polar organic media

    Energy Technology Data Exchange (ETDEWEB)

    Burn, Adam G.; Nash, Kenneth L. [Washington State Univ., Pullmann, WA (United States). Dept. of Chemistry

    2017-09-01

    Weak complexes between pentavalent and hexavalent actinyl cations have been reported to exist in acidic, non-complexing high ionic strength aqueous media. Such ''cation-cation complexes'' were first identified in the context of actinide-actinide redox reactions in acidic aqueous media relevant to solvent extraction-based separation systems, hence their characterization is of potential interest for advanced nuclear fuel reprocessing. This chemistry could be relevant to efforts to develop advanced actinide separations based on the upper oxidation states of americium, which are of current interest. In the present study, the chemical behavior of pentavalent uranyl was examined in non-aqueous, aprotic polar organic solvents (propylene carbonate and acetonitrile) to determine whether UO{sub 2}{sup +} cations generated at the reducing working electrode surface would interact with the UO{sub 2}{sup 2+} cations in the bulk phase to form cation-cation complexes in such media. In magnesium perchlorate media, the electrolyte adsorbed onto the working electrode surface and interfered with the uranyl reduction/diffusion process through an ECE (electron transfer/chemical reaction/electron transfer) mechanism. In parallel studies of uranyl redox behavior in tetrabutylammonium hexafluorophosphate solutions, an EC (electron transfer/chemical reaction) mechanism was observed in the cyclic voltammograms. Ultimately, no conclusive electrochemical evidence demonstrated uranyl cation-cation interactions in the non-aqueous, aprotic polar organic solvent solutions, though the results reported do not completely rule out the presence of UO{sub 2}{sup +}.UO{sub 2}{sup 2+} complexes.

  4. MATRIX-VBS (v1.0): Implementing an Evolving Organic Aerosol Volatility in an Aerosol Microphysics Model

    Science.gov (United States)

    Gao, Chloe Y.; Tsigaridis, Kostas; Bauer, Susanne E.

    2017-01-01

    The gas-particle partitioning and chemical aging of semi-volatile organic aerosol are presented in a newly developed box model scheme, where its effect on the growth, composition, and mixing state of particles is examined. The volatility-basis set (VBS) framework is implemented into the aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state), which resolves mass and number aerosol concentrations and in multiple mixing-state classes. The new scheme, MATRIX-VBS, has the potential to significantly advance the representation of organic aerosols in Earth system models by improving upon the conventional representation as non-volatile particulate organic matter, often also with an assumed fixed size distribution. We present results from idealized cases representing Beijing, Mexico City, a Finnish forest, and a southeastern US forest, and investigate the evolution of mass concentrations and volatility distributions for organic species across the gas and particle phases, as well as assessing their mixing state among aerosol populations. Emitted semi-volatile primary organic aerosols evaporate almost completely in the intermediate-volatility range, while they remain in the particle phase in the low-volatility range. Their volatility distribution at any point in time depends on the applied emission factors, oxidation by OH radicals, and temperature. We also compare against parallel simulations with the original scheme, which represented only the particulate and non-volatile component of the organic aerosol, examining how differently the condensed-phase organic matter is distributed across the mixing states in the model. The results demonstrate the importance of representing organic aerosol as a semi-volatile aerosol, and explicitly calculating the partitioning of organic species between the gas and particulate phases.

  5. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate

    Science.gov (United States)

    Tsigaridis, Konsta; Bauer, Susanne E.

    2015-01-01

    Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions.

  6. The Atmospheric Oxidation of Volatile Organic Compounds Through Hydrogen Shift Reactions

    DEFF Research Database (Denmark)

    Knap, Hasse Christian

    In this thesis the unimolecular hydrogen transfer reactions (H-shift) in peroxy and acyl peroxy radicals derived from the atmospheric oxidation of volatile organic compounds (VOC) have been investigated. A unimolecular isomerization reaction where a hydrogen atom is moved internally within...... the reaction rate constants of the H-shift reactions. The autoxidation of volatile organic compounds is an important oxidation mechanism that produces secondary organic aerosols (SOA) and recycles hydroxyl (OH) radicals. The autoxidation cycle produces a second generation peroxy radical (OOQOOH) through...... through the alcoholic H-shift reactions is unlikely. Finally, I have observed that the M06-2X/augcc- pVTZ and wB97X-D/aug-cc-pVTZ methods calculate H-shift reaction rate constants that are comparable to single-point ROHF-CCSD(T)-F12a/cc-pVDZ-F12 calculations....

  7. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    International Nuclear Information System (INIS)

    Daisey, J.M.

    1991-11-01

    There is considerable interest in the ''unattached'' fraction of radon progeny in indoor air because of its significance to the estimation of the risks of radon exposure. Because of its high mobility in air, the unattached fraction is more efficiently deposited in the respiratory tract. Variation in the diameter of the ''unattached'' fraction and in its diffusion coefficient can be due to clustering of other atmospheric species around the 218 PoO 2 + ion. The purpose of this study was to investigate the potential for the formation of clusters of vapor phase organic compounds, found in indoor air, around the 218 PoO 2 + ion and to determine which were most likely to form clusters. A secondary purpose was to provide a compilation of measurements of indoor organic compounds for future experiments and theoretical calculations by the radon research community. The classical charged liquid droplet theory (Thomson equation) was used to estimate the Gibbs free energy of ion-induced nucleation and to provide an indication of the indoor organic compounds most likely to undergo ion-induced nucleation. Forty-four volatile and semi-volatile organic compounds out of the more than 300 which have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the 218 PoO 2 + ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones and the acetates) and the semi-volatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos)

  8. Measurements of chlorinated volatile organic compounds emitted from office printers and photocopiers.

    Science.gov (United States)

    Kowalska, Joanna; Szewczyńska, Małgorzata; Pośniak, Małgorzata

    2015-04-01

    Office devices can release volatile organic compounds (VOCs) partly generated by toners and inks, as well as particles of paper. The aim of the presented study is to identify indoor emissions of volatile halogenated organic compounds into the office workspace environment. Mixtures of organic pollutants emitted by seven office devices, i.e. printers and copiers, were analyzed by taking samples in laboratory conditions during the operation of these appliances. Tests of volatile organic compound emissions from selected office devices were conducted in a simulated environment (test chamber). Samples of VOCs were collected using three-layered thermal desorption tubes. Separation and identification of organic pollutant emissions were made using thermal desorption combined with gas chromatography coupled to mass spectrometry. Test chamber studies indicated that operation of the office printer and copier would contribute to the significant concentration level of VOCs in typical office indoor air. Among the determined volatile halogenated compounds, only chlorinated organic compounds were identified, inter alia: trichloroethylene - carcinogenic - and tetrachloroethylene - possibly carcinogenic to human. The results show that daily exposure of an office worker to chemical factors released by the tested printing and copying units can be variable in terms of concentrations of VOCs. The highest emissions in the test chamber during printing were measured for ethylbenzene up to 41.3 μg m(-3), xylenes up to 40.5 μg m(-3) and in case of halogenated compounds the highest concentration for chlorobenzene was 6.48 μg m(-3). The study included the comparison of chamber concentrations and unit-specific emission rates of selected VOCs and the identified halogenated compounds. The highest amount of total VOCs was emitted while copying with device D and was rated above 1235 μg m(-3) and 8400 μg unit(-1) h(-1) on average.

  9. Analysis of Organic Volatile Flavor Compounds in Fermented Stinky Tofu Using SPME with Different Fiber Coatings

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2012-03-01

    Full Text Available 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.

  10. Detection of semi-volatile organic compounds in permeable ...

    Science.gov (United States)

    Abstract The Edison Environmental Center (EEC) has a research and demonstration permeable parking lot comprised of three different permeable systems: permeable asphalt, porous concrete and interlocking concrete permeable pavers. Water quality and quantity analysis has been ongoing since January, 2010. This paper describes a subset of the water quality analysis, analysis of semivolatile organic compounds (SVOCs) to determine if hydrocarbons were in water infiltrated through the permeable surfaces. SVOCs were analyzed in samples collected from 11 dates over a 3 year period, from 2/8/2010 to 4/1/2013.Results are broadly divided into three categories: 42 chemicals were never detected; 12 chemicals (11 chemical test) were detected at a rate of less than 10% or less; and 22 chemicals were detected at a frequency of 10% or greater (ranging from 10% to 66.5% detections). Fundamental and exploratory statistical analyses were performed on these latter analyses results by grouping results by surface type. The statistical analyses were limited due to low frequency of detections and dilutions of samples which impacted detection limits. The infiltrate data through three permeable surfaces were analyzed as non-parametric data by the Kaplan-Meier estimation method for fundamental statistics; there were some statistically observable difference in concentration between pavement types when using Tarone-Ware Comparison Hypothesis Test. Additionally Spearman Rank order non-parame

  11. Increase in volatilization of organic compounds using air sparging through addition in alcohol in a soil-water system.

    Science.gov (United States)

    Chao, Huan-Ping; Hsieh, Lin-Han Chiang; Tran, Hai Nguyen

    2018-02-15

    This study developed a novel method to promote the remediation efficiency of air sparging. According to the enhanced-volatilization theory presented in this study, selected alcohols added to groundwater can highly enhance the volatilization amounts of organic compounds with high Henry's law constants. In this study, the target organic compounds consisted of n-hexane, n-heptane, benzene, toluene, 1,1,2-trichloroethane, and tetrachloroethene. n-pentanol, n-hexanol, and n-heptanol were used to examine the changes in the volatilization amounts of organic compounds in the given period. Two types of soils with high and low organic matter were applied to evaluate the transport of organic compounds in the soil-water system. The volatilization amounts of the organic compounds increased with increasing alcohol concentrations. The volatilization amounts of the test organic compounds exhibited a decreasing order: n-heptanol>n-hexanol>n-pentanol. When 10mg/L n-heptanol was added to the system, the maximum volatilization enhancement rate was 18-fold higher than that in distilled water. Samples of soil with high organic matter might reduce the volatilization amounts by a factor of 5-10. In the present study, the optimal removal efficiency for aromatic compounds was approximately 98%. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. A global perspective on aerosol from low-volatility organic compounds

    Directory of Open Access Journals (Sweden)

    H. O. T. Pye

    2010-05-01

    Full Text Available Global production of organic aerosol from primary emissions of semivolatile (SVOCs and intermediate (IVOCs volatility organic compounds is estimated using the global chemical transport model, GEOS-Chem. SVOC oxidation is predicted to be a larger global source of net aerosol production than oxidation of traditional parent hydrocarbons (terpenes, isoprene, and aromatics. Using a prescribed rate constant and reduction in volatility for atmospheric oxidation, the yield of aerosol from SVOCs is predicted to be about 75% on a global, annually-averaged basis. For IVOCs, the use of a naphthalene-like surrogate with different high-NOx and low-NOx parameterizations produces a global aerosol yield of about 30%, or roughly 5 Tg/yr of aerosol. Estimates of the total global organic aerosol source presented here range between 60 and 100 Tg/yr. This range reflects uncertainty in the parameters for SVOC volatility, SVOC oxidation, SVOC emissions, and IVOC emissions, as well as wet deposition. The highest estimates result if SVOC emissions are significantly underestimated (by more than a factor of 2 or if wet deposition of the gas-phase semivolatile species is less effective than previous estimates. A significant increase in SVOC emissions, a reduction of the volatility of the SVOC emissions, or an increase in the enthalpy of vaporization of the organic aerosol all lead to an appreciable reduction of prediction/measurement discrepancy. In addition, if current primary organic aerosol (POA inventories capture only about one-half of the SVOC emission and the Henrys Law coefficient for oxidized semivolatiles is on the order of 103 M/atm, a global estimate of OA production is not inconsistent with the top-down estimate of 140 Tg/yr by (Goldstein and Galbally, 2007. Additional information is needed to constrain the emissions and treatment of SVOCs and IVOCs, which have traditionally not been included in models.

  13. Synergism among volatile organic compounds resulting in increased antibiosis in Oidium sp.

    Science.gov (United States)

    Strobel, Gary A; Spang, Shanney; Kluck, Katreena; Hess, W M; Sears, Joe; Livinghouse, Tom

    2008-06-01

    Oidium sp. has been recovered as an endophyte in Terminalia catappa (tropical chestnut) in Costa Rica. The volatile organic compounds (VOCs) of this organism uniquely and primarily consist of esters of propanoic acid, 2-methyl-, butanoic acid, 2-methyl-, and butanoic acid, 3-methyl-. The VOCs of Oidium sp. are slightly inhibitory to many plant pathogenic fungi. Previous work on the VOCs of Muscodor albus demonstrated that besides esters of small organic acids, a small organic acid and a naphthalene derivative were needed to obtain maximum antibiotic activity. Thus, the addition of exogenous volatile compounds such as isobutyric acid and naphthalene, 1,1'-oxybis caused a dramatic synergistic increase in the antibiotic activity of the VOCs of Oidium sp. against Pythium ultimum. In fact, at elevated concentrations, there was not only 100% inhibition of P. ultimum but killing as well. In addition, a coculture of Muscodor vitigenus (making only naphthalene) and Oidium sp. plus isobutyric acid produced an additive antibiosis effect against P. ultimum. The biological implications of multiple volatile compounds acting to bring about antibiosis in nature are discussed.

  14. Sol-gel-based SPME fiber as a reliable sampling technique for studying biogenic volatile organic compounds released from Clostridium tetani.

    Science.gov (United States)

    Ghader, Masoud; Shokoufi, Nader; Es-Haghi, Ali; Kargosha, Kazem

    2017-11-01

    A novel and efficient headspace solid-phase microextraction (HS-SPME) method, followed by gas chromatography mass spectrometry (GC-MS), was developed to study volatile organic compounds (VOCs) emerging from microorganisms. Two homemade SPME fibers, a semi-polar poly (dimethylsiloxane) (PDMS) fiber, and a polar polyethylene glycol (PEG) fiber, along with two commercial fibers (PDMS and PDMS/DVB) were used to collect VOCs emerging from Clostridium tetani which was cultured in different media. The adsorbed VOCs were desorbed and identified, in vitro, using GC-MS. The adsorption efficiency was improved by optimizing the time duration of adsorption and desorption. About 50 components were identified by the proposed method. The main detected compounds appeared to be sulfur containing compounds such as butanethioic acid S-methyl ester, dimethyl trisulfide, and dimethyl tetrasulfide. These volatile sulfur containing compounds are derived from amino acids containing the sulfur element, which probably coexist in the mentioned bacterium or are added to the culture media. The developed HS-SPME-GC-MS method allowed the determination of the chemical fingerprint of Clostridium tetani volatile constituents, and thus provides a new, simple, and reliable tool for studying the growth of microorganisms. Graphical abstract Investigation of biogenic VOCs released from Clostridium tetani using SPME-GC-MS.

  15. [Emission characteristics and hazard assessment analysis of volatile organic compounds from chemical synthesis pharmaceutical industry].

    Science.gov (United States)

    Li, Yan; Wang, Zhe-Ming; Song, Shuang; Xu, Zhi-Rong; Xu, Ming-Zhu; Xu, Wei-Li

    2014-10-01

    In this study, volatile organic compounds (VOCs) released from chemical synthesis pharmaceutical industry in Taizhou, Zhejiang province were analyzed quantitatively and qualitatively. The total volatile organic compounds (TVOCs) was in the range of 14.9-308.6 mg · m(-3). Evaluation models of ozone formation potentials (OFP) and health risk assessment were adopted to preliminarily assess the environmental impact and health risk of VOCs. The results showed that the values of OFP of VOCs were in the range of 3.1-315.1 mg · m(-3), based on the maximum incremental reactivity, the main principal contribution was toluene, tetrahydrofuran (THF), acetic ether etc. The non-carcinogenic risk and the carcinogen risk fell in the ranges of 9.48 x 10(-7)-4.98 x 10(-4) a(-1) and 3.17 x 10(-5)- 6.33 x 10(-3). The principal contribution of VOCs was benzene, formaldehyde and methylene chloride.

  16. Impacts of volatile organic compounds on ground water, health hazards, public awareness, solutions

    International Nuclear Information System (INIS)

    Pawlowicz, G.; Carter, C.C.

    1991-01-01

    There are many potential sources of ground water contamination - gasoline and related products are one of them. To deal with a problem of this magnitude, the 1986 Legislature initiated the State Underground Petroleum Environmental Response Act program. Implementation of this program has aided in the detection and elimination of human exposure to drinking water contaminated by volatile organic compounds from leaking underground storage systems. When violations of the maximum contaminant levels were in question, corrective actions such as connection to a non-contaminated public water supply or installation of petroleum removal filter systems have been necessary in many cases for consumer protection. A monitoring program for polluted aquifers, based on existing wells, has also been established to detect any adverse changes in potable ground water quality for public protection. This paper discusses the volatile organic ground water contamination of both public and private water supplies in Duval County, Florida with emphasis on health risks, the impact on the communities involved, and solutions

  17. Volatile chemical products emerging as largest petrochemical source of urban organic emissions

    Science.gov (United States)

    McDonald, Brian C.; de Gouw, Joost A.; Gilman, Jessica B.; Jathar, Shantanu H.; Akherati, Ali; Cappa, Christopher D.; Jimenez, Jose L.; Lee-Taylor, Julia; Hayes, Patrick L.; McKeen, Stuart A.; Cui, Yu Yan; Kim, Si-Wan; Gentner, Drew R.; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Harley, Robert A.; Frost, Gregory J.; Roberts, James M.; Ryerson, Thomas B.; Trainer, Michael

    2018-02-01

    A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)—including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products—now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.

  18. Studies of volatiles and organic materials in early terrestrial and present-day outer solar system environments

    Science.gov (United States)

    Sagan, Carl; Thompson, W. Reid; Chyba, Christopher F.; Khare, B. N.

    1991-01-01

    A review and partial summary of projects within several areas of research generally involving the origin, distribution, chemistry, and spectral/dielectric properties of volatiles and organic materials in the outer solar system and early terrestrial environments are presented. The major topics covered include: (1) impact delivery of volatiles and organic compounds to the early terrestrial planets; (2) optical constants measurements; (3) spectral classification, chemical processes, and distribution of materials; and (4) radar properties of ice, hydrocarbons, and organic heteropolymers.

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

    Science.gov (United States)

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

    2014-04-01

    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, 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

  20. Analytical modelling of stable isotope fractionation of volatile organic compounds in the unsaturated zone

    OpenAIRE

    Bouchard, D.; Cornaton, F.; Höhener, P.; Hunkeler, D.

    2011-01-01

    Analytical models were developed that simulate stable isotope ratios of volatile organic compounds (VOCs) near a point source contamination in the unsaturated zone. The models describe diffusive transport of VOCs, biodegradation and source ageing. The mass transport is governed by Fick's law for diffusion. The equation for reactive transport of VOCs in the soil gas phase was solved for different source geometries and for different boundary conditions. Model results were compared to experiment...

  1. Migration of volatile organic contaminations (VOCs) through a deforming clay liner

    OpenAIRE

    Zhang, H. J.; Jeng, Dong-Sheng; Barry, David Andrew; Seymour, Brian R.; Li, Ling

    2013-01-01

    A fully coupled thermal–hydraulic–mechanical–chemical (THMC) model was proposed to describe the migration of volatile organic contaminations (VOCs) in unsaturated landfill liners. The vertical soil stress, capillary pressure, air pressure, temperature increase, and solute concentration were selected as the primary variables. Finite deformations were described using Lagrangian coordinates. Non-isothermal moisture transport was found to be dependent on both the temperature gradient and the conc...

  2. Analysis of volatile organic compounds by cryogenic oven trapping gas chromatography

    OpenAIRE

    渡部, 加奈子; 石井, 晃; 李, 暁鵬; 鈴木, 修; 鈴木, 加奈子

    2000-01-01

    Recently, a microcomputer-controlled device for lowering oven temperature below 0℃ has become available for new types of gas chromatography (GC) instruments. This device was originally designed for rapid cooling of an oven to reduce the time for analysis. In our laboratories, we are using it for trapping volatile organic compounds (VOCs) inside a capillary column at cryogenic oven temperatures; as much as 5 ml of headspace vapor can be injected into a medium-bore capillary column without any ...

  3. Symptoms of mothers and infants related to total volatile organic compounds in household products

    OpenAIRE

    Farrow, A; Taylor, H; Northstone, K; Golding, J

    2003-01-01

    The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that ...

  4. Rapid mineralization of biogenic volatile organic compounds in temperate and Arctic soils

    OpenAIRE

    Albers, Christian Nyrop; Kramshøj, Magnus; Rinnan, Riikka

    2018-01-01

    Biogenic volatile organic compounds (BVOCs) are produced by all life forms. Their release into the atmosphere is important with regards to a number of physical and chemical processes and great effort has been put into determining sources and sinks of these compounds in recent years. Soil microbes as a possible sink for BVOCs in the atmosphere has been suggested, however, experimental evidence for this sink is scarce despite its potentially high importance to both carbon cycling and atmospheri...

  5. [Photoionization ion mobility spectrometry (UV-IMS) for the isomeric volatile organic compounds].

    Science.gov (United States)

    Li, Hu; Niu, Wen-qi; Wang, Hong-mei; Huang, Chao-qun; Jiang, Hai-he; Chu, Yan-nan

    2012-01-01

    The construction and performance study is reported for a newly developed ultraviolet photoionization ion mobility spectrometry (UV-IMS). In the present paper, an UV-IMS technique was firstly developed to detect eleven isomeric volatile organic compounds including the differences in the structure of carbon chain, the style of function group and the position of function group. Their reduced mobility values were determined and increased in this order: linears alcohols homemade UV-IMS was around ppb-ppm.

  6. A Compendium of Volatile Organic Compounds (VOCs) Released By Human Cell Lines

    OpenAIRE

    Filipiak, Wojciech; Mochalski, Pawel; Filipiak, Anna; Ager, Clemens; Cumeras, Raquel; Davis, Cristina E.; Agapiou, Agapios; Unterkofler, Karl; Troppmair, Jakob

    2016-01-01

    Volatile organic compounds (VOCs) offer unique insights into ongoing biochemical processes in healthy and diseased humans. Yet, their diagnostic use is hampered by the limited understanding of their biochemical or cellular origin and their frequently unclear link to the underlying diseases. Major advancements are expected from the analyses of human primary cells, cell lines and cultures of microorganisms. In this review, a database of 125 reliably identified VOCs previously reported for human...

  7. Wet effluent diffusion denuder technique and the determination of volatile organic compounds in air. II. Monoterpenes

    Czech Academy of Sciences Publication Activity Database

    Sklenská, Jana; Broškovičová, Anna; Večeřa, Zbyněk

    2002-01-01

    Roč. 973, 1-2 (2002), s. 211-216 ISSN 0021-9673 R&D Projects: GA ČR GA203/98/0943 Grant - others:SPSDII(XE) EV/02/11 Institutional research plan: CEZ:AV0Z4031919 Keywords : wet effluent denuder technique * volatile organic compounds * monoterpenes Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.098, year: 2002

  8. Assessing the chemotaxis behavior of Physarum polycephalum to a range of simple volatile organic chemicals

    OpenAIRE

    de Lacy Costello, Ben P.J.; Adamatzky, Andrew I.

    2013-01-01

    The chemotaxis behavior of the plasmodial stage of the true slime mold Physarum Polycephalum was assessed when given a binary choice between two volatile organic chemicals (VOCs) placed in its environment. All possible binary combinations were tested between 19 separate VOCs selected due to their prevalence and biological activity in common plant and insect species. The slime mold exhibited positive chemotaxis toward a number of VOCs with the following order of preference: ? Farnesene > ?-myr...

  9. Performance specifications for technology development: Application for characterization of volatile organic compounds in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, S.E.; Doskey, P.V.; Erickson, M.D.; Lindahl, P.C.

    1994-07-01

    This report contains information about technology development for the monitoring and remediation of environmental pollution caused by the release of volatile organic compounds. Topics discussed include: performance specification processes, gas chromatography, mass spectrometer, fiber-optic chemical sensors, infrared spectroscopy, Raman spectroscopy, piezoelectric sensors and electrochemical sensors. These methods are analyzed for their cost efficiency, accuracy, and the ability to meet the needs of the customer.

  10. Gene expression profiles of human promyelocytic leukemia cell lines exposed to volatile organic compounds.

    Science.gov (United States)

    Sarma, Sailendra Nath; Kim, Youn-Jung; Ryu, Jae-Chun

    2010-05-27

    Benzene, toluene, o-xylene, ethylbenzene, trichloroethylene and dichloromethane are the most widely used volatile organic compounds (VOCs), and their toxic mechanisms are still undefined. This study analyzed the genome-wide expression profiles of human promyelocytic leukemia HL-60 cells exposed to VOCs using a 35-K whole human genome oligonucleotide microarray to ascertain potential biomarkers. Genes with a significantly increased expression levels (over 1.5-fold and p-values lines to VOC exposure.

  11. Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill

    OpenAIRE

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan; Yi, Jongheop

    2012-01-01

    Objectives The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the res...

  12. Potential of antimicrobial volatile organic compounds to control Sclerotinia sclerotiorum in bean seeds

    OpenAIRE

    Fialho, Maurício Batista; Moraes, Maria Heloisa Duarte de; Tremocoldi, Annelise Roberta; Pascholati, Sérgio Florentino

    2011-01-01

    The objective of this work was to evaluate the potential of an artificial mixture of volatile organic compounds (VOCs), produced by Saccharomyces cerevisiae, to control Sclerotinia sclerotiorum in vitro and in bean seeds. The phytopathogenic fungus was exposed, in polystyrene plates, to an artificial atmosphere containing a mixture of six VOCs formed by alcohols (ethanol, 3-methyl-1-butanol, 2-methyl-1-butanol and phenylethyl alcohol) and esters (ethyl acetate and ethyl octanoate), in the pro...

  13. Measurement and classification method regarding the emission of volatile organic compounds from cleanroom materials

    OpenAIRE

    Keller, Markus; Gommel, Udo; Verl, Alexander

    2012-01-01

    In controlled environments and cleanroom technology, construction materials implemented in specific applications need to be assessed for emissions of volatile organic compounds (VOC) and classified in order to permit direct comparisons to be made. The paper presents a standardized procedure for testing and classifying materials with uniform sample preparation and defined storage times. It describes preparation of the samples, their storage in a VOC-reduced minienvironment, avoidance of cross-...

  14. Analysis of volatile organic compound from Elaeis guineensis inflorescences planted on different soil types in Malaysia

    Science.gov (United States)

    Muhamad Fahmi, M. H.; Ahmad Bukhary, A. K.; Norma, H.; Idris, A. B.

    2016-11-01

    The main attractant compound for Eleidobius kamerunicus to male spikelet Elaeis guineensis (oil palm) were determined by analyzing volatile organic compound extracted from E. guineenses inflorescences planted on different soil types namely peat soil, clay soil and sandy soil. Anthesizing male oil palm inflorescences were randomly choosen from palm aged between 4-5 years old age. Extraction of the volatiles from the oil palm inflorescences were performed by Accelerated Solvent Extraction method (ASE). The extracted volatile compound were determined by using gas chromatography-mass spectrometry. Out of ten identified compound, estragole was found to be a major compound in sandy soil (37.49%), clay soil (30.71%) and peat soil (27.79%). Other compound such as 9,12-octadecadieonic acid and n-hexadecanoic acid were found as major compound in peat soil (27.18%) and (7.45%); sandy soil (14.15 %) and (9.31%); and clay soil (30.23%) and (4.99%). This study shows that estragole was the predominant volatile compound detected in oil palm inflorescences with highly concentrated in palm planted in sandy soil type.

  15. Factors Effecting the Total Volatile Organic Compound (TVOC Concentrations in Slovak Households

    Directory of Open Access Journals (Sweden)

    Ľudmila Mečiarová

    2017-11-01

    Full Text Available Thirty five Slovak households were selected for an investigation of indoor environmental quality. Measuring of indoor air physical and chemical factors and a questionnaire survey was performed during May 2017. The range of permissible operative temperature was not met in 11% of objects. Relative humidity met the legislative requirements in all monitored homes. Concentrations of total volatile organic compounds (TVOCs were significantly higher in the apartments than in the family houses. The average TVOC levels in the apartments and family houses were 519.7 µg/m3 and 330.2 µg/m3, respectively. Statistical analysis confirmed the effect of indoor air temperature, relative humidity and particulate matter (PM0.5 and PM1 on the levels of TVOCs. Higher TVOC levels were observed also in homes where it is not a common practice to open windows during cleaning activities. Other factors that had a statistically significant effect on concentrations of volatile organic compounds were heating type, attached garage, location of the apartment within residential building (the floor, as well as number of occupants. Higher TVOC concentrations were observed in indoor than outdoor environment, while further analysis showed the significant impact of indoor emission sources on the level of these compounds in buildings. The questionnaire study showed a discrepancy between objective measurement and subjective assessment in the household environment, and pointed to insufficient public awareness about volatile organic compounds (VOCs.

  16. Biogenic volatile organic compounds from the urban forest of the Metropolitan Region, Chile

    International Nuclear Information System (INIS)

    Préndez, Margarita; Carvajal, Virginia; Corada, Karina; Morales, Johanna; Alarcón, Francis; Peralta, Hugo

    2013-01-01

    Tropospheric ozone is a secondary pollutant whose primary sources are volatile organic compounds and nitrogen oxides. The national standard is exceeded on a third of summer days in some areas of the Chilean Metropolitan Region (MR). This study reports normalized springtime experimental emissions factors (EF) for biogenic volatile organic compounds from tree species corresponding to approximately 31% of urban trees in the MR. A Photochemical Ozone Creation Index (POCI) was calculated using Photochemical Ozone Creation Potential of quantified terpenes. Ten species, natives and exotics, were analysed using static enclosure technique. Terpene quantification was performed using GC-FID, thermal desorption, cryogenic concentration and automatic injection. Observed EF and POCI values for terpenes from exotic species were 78 times greater than native values; within the same family, exotic EF and POCI values were 28 and 26 times greater than natives. These results support reforestation with native species for improved urban pollution management. -- First experimental determination of the emission factors of biogenic volatile organic compounds in the urban forest of the Metropolitan Region, Chile

  17. Ground-Water Issue: Soil sampling and analysis for volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, T.E.; Crockett, A.B.; Siegrist, R.L.; Zarrabi, K.

    1991-02-01

    The Regional Superfund Ground Water Forum is a group of ground-water scientists that represents EPA's Regional Superfund Offices. The forum was organized to exchange up-to-date information related to groundwater remediation at Superfund sites. Sampling of soils for volatile organic compounds (VOCs) is an issue identified by the Ground Water Forum as a concern of Superfund decision makers. Concerns over data quality have raised many questions related to sampling soils for 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). 53 refs., 6 figs., 12 tabs.

  18. The human volatilome: volatile organic compounds (VOCs) in exhaled breath, skin emanations, urine, feces and saliva.

    Science.gov (United States)

    Amann, Anton; Costello, Ben de Lacy; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Pleil, Joachim; Ratcliffe, Norman; Risby, Terence

    2014-09-01

    Breath analysis is a young field of research with its roots in antiquity. Antoine Lavoisier discovered carbon dioxide in exhaled breath during the period 1777-1783, Wilhelm (Vilém) Petters discovered acetone in breath in 1857 and Johannes Müller reported the first quantitative measurements of acetone in 1898. A recent review reported 1765 volatile compounds appearing in exhaled breath, skin emanations, urine, saliva, human breast milk, blood and feces. For a large number of compounds, real-time analysis of exhaled breath or skin emanations has been performed, e.g., during exertion of effort on a stationary bicycle or during sleep. Volatile compounds in exhaled breath, which record historical exposure, are called the 'exposome'. Changes in biogenic volatile organic compound concentrations can be used to mirror metabolic or (patho)physiological processes in the whole body or blood concentrations of drugs (e.g. propofol) in clinical settings-even during artificial ventilation or during surgery. Also compounds released by bacterial strains like Pseudomonas aeruginosa or Streptococcus pneumonia could be very interesting. Methyl methacrylate (CAS 80-62-6), for example, was observed in the headspace of Streptococcus pneumonia in concentrations up to 1420 ppb. Fecal volatiles have been implicated in differentiating certain infectious bowel diseases such as Clostridium difficile, Campylobacter, Salmonella and Cholera. They have also been used to differentiate other non-infectious conditions such as irritable bowel syndrome and inflammatory bowel disease. In addition, alterations in urine volatiles have been used to detect urinary tract infections, bladder, prostate and other cancers. Peroxidation of lipids and other biomolecules by reactive oxygen species produce volatile compounds like ethane and 1-pentane. Noninvasive detection and therapeutic monitoring of oxidative stress would be highly desirable in autoimmunological, neurological, inflammatory diseases and cancer

  19. Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene

    Directory of Open Access Journals (Sweden)

    Ludmilla Lumholdt

    2014-11-01

    Full Text Available Polypropylene nonwovens were functionalised using a self-assembled, amphiphilic cyclodextrin coating and the potential for water purification by removal of pollutants was studied. As benzene is one of the problematic compounds in the Water Framework Directive, six volatile organic compounds (benzene and five benzene-based substances were chosen as model compounds. The compounds were tested as a mixture in order to provide a more realistic situation since the wastewater will be a complex mixture containing multiple pollutants. The volatile organic compounds are known to form stable inclusion complexes with cyclodextrins. Six different amphiphilic cyclodextrin derivatives were synthesised in order to elucidate whether or not the uptake abilities of the coating depend on the structure of the derivative. Headspace gas chromatography was used for quantification of the uptake exploiting the volatile nature of benzene and its derivatives. The capacity was shown to increase beyond the expected stoichiometries of guest–host complexes with ratios of up to 16:1.

  20. Determination of Partition coefficients for a Mixture of Volatile Organic Compounds in Rats and Humans at Different Life Stages

    National Research Council Canada - National Science Library

    Mahle, Deidre A; Gearhart, Jeffrey M; Godfrey, Richard J; Mattie, David R; Cook, Robert S; Grisby, Claude C

    2004-01-01

    .... Partition coefficients (PCs) are an integral component of pharmacokinetic models and determining differences in tissue partitioning of volatile organic chemicals across life stages can help reduce the uncertainty in risk assessment...

  1. Application of horizontal spiral coil heat exchanger for volatile organic compounds (VOC) emission control.

    Science.gov (United States)

    Deshpande, P M; Dawande, S D

    2013-04-01

    The petroleum products have wide range of volatility and are required to be stored in bulk. The evaporation losses are significant and it is a economic as well as environmental concern, since evaporative losses of petroleum products cause increased VOC in ambient air. Control of these losses poses a major problem for the storage tank designers. Ever rising cost of petroleum products further adds to the gravity of the problem. Condensation is one of the technologies for reducing volatile organic compounds emissions. Condensation is effected by condenser, which is basically a heat exchanger and the heat exchanger configuration plays an important role. The horizontal spiral coil heat exchanger is a promising configuration that finds an application in VOC control. This paper attempts to understand underlying causes of emissions and analyse the option of horizontal spiral coil heat exchanger as vent condenser.

  2. Study of the influence of temperature the venting depollution process of soils contaminated with volatile organic compounds

    OpenAIRE

    GABRIELA-ALINA BRUSTUREAN; JEAN CARRÉ; DELIA PERJU; TEODOR TODINCA

    2006-01-01

    Venting is one of the most used in situ remediation methods for unsaturated soils contaiminated with volatile organic compounds (VOC). The development of mathematical models and their validation by means of experimental results allowed the identification of the main parameters which influence the soil depollution process. The influence of temperature on the venting depollution process of soils polluted with volatile organic compounds was studied in this investigation. It was found that the de...

  3. Determination of Volatile Organic Compounds in Fourty Five Salvia Species by Thermal Desorption-GC-MS Technique

    OpenAIRE

    Seda Damla Hatipoglu; Nihal Zorlu; Tuncay Dirmenci; Ahmet C. Goren; Turan Ozturk; Gulacti Topcu

    2016-01-01

    Volatile organic compounds (VOC) from dried aerial parts (flowers, leafs, leafy branches and stems) of fourty five Salvia species, harvested from different regions of Turkey, were determined using thermal desorption technique coupled to gas chromatography-mass spectrometer (TD-GC-MS). Total percentages of the detected volatile organic compounds of the Salvia species ranged from 70.30 to 99.65% . Total yield of VOC was found to be highly variable among Salvia species, and the percentage of eac...

  4. Ion mobility spectrometry for microbial volatile organic compounds: a new identification tool for human pathogenic bacteria.

    Science.gov (United States)

    Jünger, Melanie; Vautz, Wolfgang; Kuhns, Martin; Hofmann, Lena; Ulbricht, Siobhán; Baumbach, Jörg Ingo; Quintel, Michael; Perl, Thorsten

    2012-03-01

    Presently, 2 to 4 days elapse between sampling at infection suspicion and result of microbial diagnostics. This delay for the identification of pathogens causes quite often a late and/or inappropriate initiation of therapy for patients suffering from infections. Bad outcome and high hospitalization costs are the consequences of these currently existing limited pathogen identification possibilities. For this reason, we aimed to apply the innovative method multi-capillary column-ion mobility spectrometry (MCC-IMS) for a fast identification of human pathogenic bacteria by determination of their characteristic volatile metabolomes. We determined volatile organic compound (VOC) patterns in headspace of 15 human pathogenic bacteria, which were grown for 24 h on Columbia blood agar plates. Besides MCC-IMS determination, we also used thermal desorption-gas chromatography-mass spectrometry measurements to confirm and evaluate obtained MCC-IMS data and if possible to assign volatile compounds to unknown MCC-IMS signals. Up to 21 specific signals have been determined by MCC-IMS for Proteus mirabilis possessing the most VOCs of all investigated strains. Of particular importance is the result that all investigated strains showed different VOC patterns by MCC-IMS using positive and negative ion mode for every single strain. Thus, the discrimination of investigated bacteria is possible by detection of their volatile organic compounds in the chosen experimental setup with the fast and cost-effective method MCC-IMS. In a hospital routine, this method could enable the identification of pathogens already after 24 h with the consequence that a specific therapy could be initiated significantly earlier.

  5. Detection, Composition and Treatment of Volatile Organic Compounds from Waste Treatment Plants

    Directory of Open Access Journals (Sweden)

    Antoni Sánchez

    2011-04-01

    Full Text Available Environmental policies at the European and global level support the diversion of wastes from landfills for their treatment in different facilities. Organic waste is mainly treated or valorized through composting, anaerobic digestion or a combination of both treatments. Thus, there are an increasing number of waste treatment plants using this type of biological treatment. During waste handling and biological decomposition steps a number of gaseous compounds are generated or removed from the organic matrix and emitted. Different families of Volatile Organic Compounds (VOC can be found in these emissions. Many of these compounds are also sources of odor nuisance. In fact, odors are the main source of complaints and social impacts of any waste treatment plant. This work presents a summary of the main types of VOC emitted in organic waste treatment facilities and the methods used to detect and quantify these compounds, together with the treatment methods applied to gaseous emissions commonly used in composting and anaerobic digestion facilities.

  6. Volatile organic compound emissions from different stages of Cananga odorata flower development.

    Science.gov (United States)

    Qin, Xiao-Wei; Hao, Chao-Yun; He, Shu-Zhen; Wu, Gang; Tan, Le-He; Xu, Fei; Hu, Rong-Suo

    2014-06-27

    Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to identify the volatile organic compounds (VOCs) of the different flower development stages of Cananga odorata for the evaluation of floral volatile polymorphism as a basis to determine the best time of harvest. Electronic nose results, coupled with discriminant factor analysis, suggested that emitted odors varied in different C. odorata flower development stages, including the bud, display-petal, initial-flowering, full-flowering, end-flowering, wilted-flower, and dried flower stages. The first two discriminant factors explained 97.52% of total system variance. Ninety-two compounds were detected over the flower life, and the mean Bray-Curtis similarity value was 52.45% among different flower development stages. A high level of volatile polymorphism was observed during flower development. The VOCs were largely grouped as hydrocarbons, esters, alcohols, aldehydes, phenols, acids, ketones, and ethers, and the main compound was β-caryophyllene (15.05%-33.30%). Other identified compounds were β-cubebene, D-germacrene, benzyl benzoate, and α-cubebene. Moreover, large numbers of VOCs were detected at intermediate times of flower development, and more hydrocarbons, esters, and alcohols were identified in the full-flowering stage. The full-flowering stage may be the most suitable period for C. odorata flower harvest.

  7. Volatile Organic Compound Emissions from Different Stages of Cananga odorata Flower Development

    Directory of Open Access Journals (Sweden)

    Xiao-Wei Qin

    2014-06-01

    Full Text Available Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS was used to identify the volatile organic compounds (VOCs of the different flower development stages of Cananga odorata for the evaluation of floral volatile polymorphism as a basis to determine the best time of harvest. Electronic nose results, coupled with discriminant factor analysis, suggested that emitted odors varied in different C. odorata flower development stages, including the bud, display-petal, initial-flowering, full-flowering, end-flowering, wilted-flower, and dried flower stages. The first two discriminant factors explained 97.52% of total system variance. Ninety-two compounds were detected over the flower life, and the mean Bray–Curtis similarity value was 52.45% among different flower development stages. A high level of volatile polymorphism was observed during flower development. The VOCs were largely grouped as hydrocarbons, esters, alcohols, aldehydes, phenols, acids, ketones, and ethers, and the main compound was β-caryophyllene (15.05%–33.30%. Other identified compounds were β-cubebene, D-germacrene, benzyl benzoate, and α-cubebene. Moreover, large numbers of VOCs were detected at intermediate times of flower development, and more hydrocarbons, esters, and alcohols were identified in the full-flowering stage. The full-flowering stage may be the most suitable period for C. odorata flower harvest.

  8. Analysis of volatile organic compounds in compost samples: A potential tool to determine appropriate composting time.

    Science.gov (United States)

    Zhu, Fengxiang; Pan, Zaifa; Hong, Chunlai; Wang, Weiping; Chen, Xiaoyang; Xue, Zhiyong; Yao, Yanlai

    2016-12-01

    Changes in volatile organic compound contents in compost samples during pig manure composting were studied using a headspace, solid-phase micro-extraction method (HS-SPME) followed by gas chromatography with mass spectrometric detection (GC/MS). Parameters affecting the SPME procedure were optimized as follows: the coating was carbon molecular sieve/polydimethylsiloxane (CAR/PDMS) fiber, the temperature was 60°C and the time was 30min. Under these conditions, 87 compounds were identified from 17 composting samples. Most of the volatile components could only be detected before day 22. However, benzenes, alkanes and alkenes increased and eventually stabilized after day 22. Phenol and acid substances, which are important factors for compost quality, were almost undetectable on day 39 in natural compost (NC) samples and on day 13 in maggot-treated compost (MC) samples. Our results indicate that the approach can be effectively used to determine the composting times by analysis of volatile substances in compost samples. An appropriate composting time not only ensures the quality of compost and reduces the loss of composting material but also reduces the generation of hazardous substances. The appropriate composting times for MC and NC were approximately 22days and 40days, respectively, during the summer in Zhejiang. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Methodology for the detection of contamination by hydrocarbons and further soil sampling for volatile and semi-volatile organic enrichment in former petrol stations, SE Spain

    Directory of Open Access Journals (Sweden)

    Rosa María Rosales Aranda

    2012-01-01

    Full Text Available The optimal detection and quantification of contamination plumes in soil and groundwater by petroleum organic compounds, gasoline and diesel, is critical for the reclamation of hydrocarbons contaminated soil at petrol stations. Through this study it has been achieved a sampling stage optimization in these scenarios by means of the location of potential contamination areas before sampling with the application of the 2D electrical resistivity tomography method, a geophysical non destructive technique based on resistivity measurements in soils. After the detection of hydrocarbons contaminated areas, boreholes with continuous coring were performed in a petrol station located in Murcia Region (Spain. The drillholes reached depths down to 10 m and soil samples were taken from each meter of the drilling. The optimization in the soil samples handling and storage, for both volatile and semi-volatile organic compounds determinations, was achieved by designing a soil sampler to minimize volatilization losses and in order to avoid the manual contact with the environmental samples during the sampling. The preservation of soil samples was performed according to Europe regulations and US Environmental Protection Agency recommendations into two kinds of glass vials. Moreover, it has been taken into account the determination techniques to quantify the hydrocarbon pollution based on Gas Chromatography with different detectors and headspace technique to reach a liquid-gas equilibrium for volatile analyses.

  10. Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

    Science.gov (United States)

    P. Veres; J. B. Gilman; J. M. Roberts; W. C. Kuster; C. Warneke; I. R. Burling; J. de Gouw

    2010-01-01

    We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs). The Mobile Organic Carbon Calibration System (MOCCS) combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC) conversion on a palladium surface to CO2 in the presence of...

  11. Fabrication of spray-printed organic non-volatile memory devices for low cost electronic applications

    International Nuclear Information System (INIS)

    Cha, An-Na; Ji, Yongsung; Lee, Sang-A; Noh, Yong-Young; Na, Seok-In; Bae, Sukang; Lee, Sanghyun; Kim, Tae-Wook

    2015-01-01

    Highlights: • PS:PCBM-based organic non-volatile memory devices was fabricated using spray printing. • The thickness of the film was controlled by adjusting the concentration of the PS:PCBM solutions. • The roughness of spray-printed films was poorer than that of the spin-coated film. • The minimum thickness of the printed film influenced the memory behavior more than the surface roughness. • The spray printed PS:PCBM showed excellent unipolar switching, reliability, retention, and endurance characteristics. - Abstract: We fabricated polystyrene (PS) and 6-phenyl-C61 butyric acid methyl ester (PCBM) based organic non-volatile memory devices using a spray printing technique. Due to the distinct operational properties of this technique, significant differences were observed in the macro- and microscopic features (e.g., the film quality and surface roughness) of the devices. The thickness of the film was successfully controlled by adjusting the concentration of the PS:PCBM solutions sprayed. Although the roughness of the spray-printed films was poorer than that of the spin-coated film, negligible differences were observed in the basic memory characteristics (e.g., the operation voltage range, turn on and off voltage, retention and endurance). In particular, the printing-based organic memory devices were successfully switched, as exhibited by the on/off ratio greater than two orders of magnitude at 0.3 V read voltage. The resistance state of all of the devices was maintained for more than 10 4 s, indicating their non-volatile characteristics

  12. Aqueous Oxidation of Green Leaf Volatiles as a Source of Secondary Organic Aerosol

    Science.gov (United States)

    Richards-Henderson, N. K.; Hansel, A.; Pham, A. T.; Vempati, H. S.; Valsaraj, K. T.; Anastasio, C.

    2013-12-01

    Vegetation emits volatile oxygenated hydrocarbons - the green leaf volatiles (GLVs) - which are formed from the biochemical conversion of linoleic and linolenic acids within plant cells. Stress or damage to vegetation can significantly elevate emission fluxes of these compounds, some of which are fairly water soluble. Aqueous-phase reactions of the GLVs with photochemically generated oxidants - such as hydroxyl radical (OH), singlet oxygen (1O2) and excited triplet states of organic compounds (3C*) _ might then form low-volatility products that can act as secondary organic aerosol (SOA). In order to determine if GLVs can be a significant source of secondary organic carbon in fogwater, studies of GLVs in laboratory solutions are needed to elucidate the oxidation kinetics and the corresponding SOA mass yields. In this study we are determining the second-order rate constants, and SOA mass yields, for five GLVs (cis-3-hexen-1-ol, cis-3-hexenylacetate, methyl salicylate, methyl jasmonate, and 2-methyl-3-butene-2-ol) reacting with OH,1O2 and 3C*. Experiments are performed at relevant fog water pHs, temperatures, and oxidant concentrations. Rate constants are determined using a relative rate approach in which the decay of GLVs and reference compounds are monitored as function of time by HPLC. The capacity of GLVs to form aqueous SOA was determined by following the formation of their decomposition products with HPLC-UV/DAD and HPLC-ESI/MS. SOA mass yields are measured gravimetrically from laboratory solutions containing atmospherically relevant concentrations of photooxidants and GLVs, and irradiated with simulated sunlight. We will use our results to assess the potential contribution of aqueous GLV reactions as a source of SOA in cloudy or foggy atmospheres.

  13. Volatile organic compound emissions from arctic vegetation highly responsive to experimental warming

    Science.gov (United States)

    Rinnan, Riikka; Kramshøj, Magnus; Lindwall, Frida; Schollert, Michelle; Svendsen, Sarah H.; Valolahti, Hanna

    2017-04-01

    Arctic areas are experiencing amplified climate warming that proceeds twice as fast as the global temperature increase. The increasing temperature is already causing evident alterations, e.g. changes in the vegetation cover as well as thawing of permafrost. Climate warming and the concomitant biotic and abiotic changes are likely to have strong direct and indirect effects on emission of volatile organic compounds (VOCs) from arctic vegetation. We used long-term field manipulation experiments in the Subarctic, Low Arctic and High Arctic to assess effects of climate change on VOC emissions from vegetation communities. In these experiments, we applied passive warming with open-top chambers alone and in combination with other experimental treatments in well-replicated experimental designs. Volatile emissions were sampled in situ by drawing air from plant enclosures and custom-built chambers into adsorbent cartridges, which were analyzed by thermal desorption and gas chromatography-mass spectrometry in laboratory. Emission increases by a factor of 2-5 were observed under experimental warming by only a few degrees, and the strong response seems universal for dry, mesic and wet ecosystems. In some cases, these vegetation community level responses were partly due to warming-induced increases in the VOC-emitting plant biomass, changes in species composition and the following increase in the amount of leaf litter (Valolahti et al. 2015). In other cases, the responses appeared before any vegetation changes took place (Lindwall et al. 2016) or even despite a decrease in plant biomass (Kramshøj et al. 2016). VOC emissions from arctic ecosystems seem more responsive to experimental warming than other ecosystem processes. We can thus expect large increases in future VOC emissions from this area due to the direct effects of temperature increase, and due to increasing plant biomass and a longer growing season. References Kramshøj M., Vedel-Petersen I., Schollert M., Rinnan

  14. Literature review of stabilization/solidification of volatile organic compounds and the implications for Hanford grouts

    International Nuclear Information System (INIS)

    Spence, R.D.; Osborne, S.C.

    1993-09-01

    A literature review was conducted on the stabilization/solidification of volatile organic compounds (VOCs). Based on this literature, it is likely that the limestone-containing grout will not permanently immobilize VOCs and that no presently available additives can guarantee permanent immobilization. The Westinghouse hanford company grout may be fairly effective at retarding aqueous leaching of VOCs, and commercial additives can improve this performance. Significant VOC losses do occur during stabilization/solidification, and the high temperatures of the Westinghouse Hanford Company waste and grout should exacerbate this problem. In fact, these high temperatures raise doubts about the presence of VOCs in the double-shell tanks supernates

  15. Evaluation of a methodology for toxicity testing of volatile chlorinated hydrocarbons on marine organisms.

    Science.gov (United States)

    Hunt, James; Birch, Gavin; Warne, Michael St J; Krassoi, Rick

    2009-06-01

    This study evaluated the suitability of sealed containers for toxicity testing to prevent loss of volatile chlorinated hydrocarbons (VCHs) with a range of Australian marine organisms including: micro-algae; sea urchin and oyster larvae in 44 mL sealed vials and fish larvae; amphipods; and juvenile polychaetes in 1 L sealed jars. Vials prevented volatilisation of VCHs during testing. Jars were less effective, with average losses of 46%. Growth and development of algae, sea urchins and oysters in vials was acceptable, indicating suitability of the methodology. Jars were suitable for amphipods and polychaetes; however, further evaluation of the fish test is required.

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

    Energy Technology Data Exchange (ETDEWEB)

    Center for Human Reliability Studies

    2006-06-01

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

  17. Fiber-optic multi-sensor array for detection of low concentration volatile organic compounds.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Byoung-Ho; Lee, Sang-Won; Kim, Su-Hwan; Yeom, Se-Hyuk; Lee, Seung-Ha; Kang, Shin-Won

    2013-08-26

    In this paper, we proposed a new type high sensitive volatile organic compounds (VOCs) gas sensor array that is based on the pulse width modulation technique. Four different types of solvatochromic dyes and two different types of polymers, were used to make the five different types of sensing membranes. These were deposited on the five side-polished optical fibers by a spin coater to make the five different sensing elements of the array. In order to ascertain the effectiveness of the sensors, five VOC gases were tested. Finally, principal component analysis (PCA) has been used to discriminates different types of VOCs.

  18. A Prototype Sensor for In Situ Sensing of Fine Particulate Matter and Volatile Organic Compounds.

    Science.gov (United States)

    Ng, Chee-Loon; Kai, Fuu-Ming; Tee, Ming-Hui; Tan, Nicholas; Hemond, Harold F

    2018-01-18

    Air pollution exposure causes seven million deaths per year, according to the World Health Organization. Possessing knowledge of air quality and sources of air pollution is crucial for managing air pollution and providing early warning so that a swift counteractive response can be carried out. An optical prototype sensor (AtmOptic) capable of scattering and absorbance measurements has been developed to target in situ sensing of fine particulate matter (PM2.5) and volatile organic compounds (VOCs). For particulate matter testing, a test chamber was constructed and the emission of PM2.5 from incense burning inside the chamber was measured using the AtmOptic. The weight of PM2.5 particles was collected and measured with a filter to determine their concentration and the sensor signal-to-concentration correlation. The results of the AtmOptic were also compared and found to trend well with the Dylos DC 1100 Pro air quality monitor. The absorbance spectrum of VOCs emitted from various laboratory chemicals and household products as well as a two chemical mixtures were recorded. The quantification was demonstrated, using toluene as an example, by calibrating the AtmOptic with compressed gas standards containing VOCs at different concentrations. The results demonstrated the sensor capabilities in measuring PM2.5 and volatile organic compounds.

  19. Non-volatile organic memory with sub-millimetre bending radius.

    Science.gov (United States)

    Kim, Richard Hahnkee; Kim, Hae Jin; Bae, Insung; Hwang, Sun Kak; Velusamy, Dhinesh Babu; Cho, Suk Man; Takaishi, Kazuto; Muto, Tsuyoshi; Hashizume, Daisuke; Uchiyama, Masanobu; André, Pascal; Mathevet, Fabrice; Heinrich, Benoit; Aoyama, Tetsuya; Kim, Dae-Eun; Lee, Hyungsuk; Ribierre, Jean-Charles; Park, Cheolmin

    2014-04-08

    High-performance non-volatile memory that can operate under various mechanical deformations such as bending and folding is in great demand for the future smart wearable and foldable electronics. Here we demonstrate non-volatile solution-processed ferroelectric organic field-effect transistor memories operating in p- and n-type dual mode, with excellent mechanical flexibility. Our devices contain a ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) thin insulator layer and use a quinoidal oligothiophene derivative (QQT(CN)4) as organic semiconductor. Our dual-mode field-effect devices are highly reliable with data retention and endurance of >6,000 s and 100 cycles, respectively, even after 1,000 bending cycles at both extreme bending radii as low as 500 μm and with sharp folding involving inelastic deformation of the device. Nano-indentation and nano scratch studies are performed to characterize the mechanical properties of organic layers and understand the crucial role played by QQT(CN)4 on the mechanical flexibility of our devices.

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

    Science.gov (United States)

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

    2002-08-01

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

  1. A Prototype Sensor for In Situ Sensing of Fine Particulate Matter and Volatile Organic Compounds

    Directory of Open Access Journals (Sweden)

    Chee-Loon Ng

    2018-01-01

    Full Text Available Air pollution exposure causes seven million deaths per year, according to the World Health Organization. Possessing knowledge of air quality and sources of air pollution is crucial for managing air pollution and providing early warning so that a swift counteractive response can be carried out. An optical prototype sensor (AtmOptic capable of scattering and absorbance measurements has been developed to target in situ sensing of fine particulate matter (PM2.5 and volatile organic compounds (VOCs. For particulate matter testing, a test chamber was constructed and the emission of PM2.5 from incense burning inside the chamber was measured using the AtmOptic. The weight of PM2.5 particles was collected and measured with a filter to determine their concentration and the sensor signal-to-concentration correlation. The results of the AtmOptic were also compared and found to trend well with the Dylos DC 1100 Pro air quality monitor. The absorbance spectrum of VOCs emitted from various laboratory chemicals and household products as well as a two chemical mixtures were recorded. The quantification was demonstrated, using toluene as an example, by calibrating the AtmOptic with compressed gas standards containing VOCs at different concentrations. The results demonstrated the sensor capabilities in measuring PM2.5 and volatile organic compounds.

  2. A full evaporation headspace technique with capillary GC and ITD: a means for quantitating volatile organic compounds in biological samples.

    Science.gov (United States)

    Schuberth, J

    1996-07-01

    The full evaporation technique (FET), which is a variant of headspace analysis used to overcome matrix effects, was combined with capillary gas chromatography (GC) and ion-trap detection (ITD). The aim was to enable quantitative tests of volatile organic compounds (VOCs) in blood and postmortem tissue samples. FET was applied to sample sized less than 35 mg whose VOCs were released from the matrix at an equilibration temperature of 130 degrees C. A capillary column with a nonpolar stationary phase was used for GC, and ITD was performed with the mass spectrometer run in full-scan mode. The potential of FET-GC-ITD was studied for the analysis of blood samples spiked with low concentrations of ethanol, acetone, 2-propanol, and 2-butanone and on brain tissue that contained methyl tert-butyl ether (MTBE), Benzene, toluene, ethylbenzene, o-, m-, and p-xylene, and propylbenzene. Samples were obtained from the bodies of victims who had inhaled smoke during an arson or accidental fire. There was a linear relationship between peak area and sample size, which indicates that the conditions of full evaporation were met and that the matrix effect was negated. The total analyte amount in the test sample at the limit of quantitation was in the range of 0.4-1 nmol for polar VOCs in blood and 0.03-0.1 nmol for nonpolar VOCs in brain tissue. Data on precision and accuracy of the method are reported.

  3. Response Characterization of a Fiber Optic Sensor Array with Dye-Coated Planar Waveguide for Detection of Volatile Organic Compounds

    Directory of Open Access Journals (Sweden)

    Jae-Sung Lee

    2014-07-01

    Full Text Available We have developed a multi-array side-polished optical-fiber gas sensor for the detection of volatile organic compound (VOC gases. The side-polished optical-fiber coupled with a polymer planar waveguide (PWG provides high sensitivity to alterations in refractive index. The PWG was fabricated by coating a solvatochromic dye with poly(vinylpyrrolidone. To confirm the effectiveness of the sensor, five different sensing membranes were fabricated by coating the side-polished optical-fiber using the solvatochromic dyes Reinhardt’s dye, Nile red, 4-aminophthalimide, 4-amino-N-methylphthalimide, and 4-(dimethylaminocinnamaldehyde, which have different polarities that cause changes in the effective refractive index of the sensing membrane owing to evanescent field coupling. The fabricated gas detection system was tested with five types of VOC gases, namely acetic acid, benzene, dimethylamine, ethanol, and toluene at concentrations of 1, 2,…,10 ppb. Second-regression and principal component analyses showed that the response properties of the proposed VOC gas sensor were linearly shifted bathochromically, and each gas showed different response characteristics.

  4. Organic Field Effect Transistors with Dipole-Polarized Polymer Gate Dielectrics for Control of Threshold Voltage

    OpenAIRE

    Sakai, Heisuke; Takahashi, Yoshikazu; Murata, Hideyuki

    2007-01-01

    The authors demonstrate organic field effect transistors (OFETs) with a dipole-polarized polyurea for the gate dielectrics. In the dielectrics, the internal electric field induces the mobile charge carrier in the semiconductor layer to the semiconductor-dielectric interface. OFETs with dipole-polarized gate dielectrics exhibit lower threshold voltage. With nonpolarized gate dielectrics, the threshold voltage was -11.4 V, whereas that decreased to -5.3 V with polarized gate dielectrics. In a...

  5. Removal of Indoor Volatile Organic Compounds via Photocatalytic Oxidation: A Short Review and Prospect

    Directory of Open Access Journals (Sweden)

    Yu Huang

    2016-01-01

    Full Text Available Volatile organic compounds (VOCs are ubiquitous in indoor environments. Inhalation of VOCs can cause irritation, difficulty breathing, and nausea, and damage the central nervous system as well as other organs. Formaldehyde is a particularly important VOC as it is even a carcinogen. Removal of VOCs is thus critical to control indoor air quality (IAQ. Photocatalytic oxidation has demonstrated feasibility to remove toxic VOCs and formaldehyde from indoor environments. The technique is highly-chemical stable, inexpensive, non-toxic, and capable of removing a wide variety of organics under light irradiation. In this paper, we review and summarize the traditional air cleaning methods and current photocatalytic oxidation approaches in both of VOCs and formaldehyde degradation in indoor environments. Influencing factors such as temperature, relative humidity, deactivation and reactivations of the photocatalyst are discussed. Aspects of the application of the photocatalytic technique to improve the IAQ are suggested.

  6. The role of low-volatility organic compounds in initial particle growth in the atmosphere

    CERN Document Server

    Tröstl, Jasmin; Gordon, Hamish; Heinritzi, Martin; Yan, Chao; Molteni, Ugo; Ahlm, Lars; Frege, Carla; Bianchi, Federico; Wagner, Robert; Simon, Mario; Lehtipalo, Katrianne; Williamson, Christina; Craven, Jill S; Duplissy, Jonathan; Adamov, Alexey; Almeida, Joao; Bernhammer, Anne-Kathrin; Breitenlechner, Martin; Brilke, Sophia; Dias, Antònio; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Gysel, Martin; Hansel, Armin; Hoyle, Christopher R; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lawler, Michael; Leiminger, Markus; Mathot, Serge; Möhler, Ottmar; Nieminen, Tuomo; Onnela, Antti; Petäjä, Tuukka; Piel, Felix M; Miettinen, Pasi; Rissanen, Matti P; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Sengupta, Kamalika; Sipilä, Mikko; Smith, James; Steiner, Gerhard; Tomè, Antònio; Virtanen, Annele; Wagner, Andrea C; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Carslaw, Kenneth S; Curtius, Joachim; Dommen, Josef; Kirkby, Jasper; Kulmala, Markku; Riipinen, Ilona; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2016-01-01

    About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles, thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer. Although recent studies predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon, and the presence of a possible Kelv...

  7. Comparison of the neurotoxicities between volatile organic compounds and fragrant organic compounds on human neuroblastoma SK-N-SH cells and primary cultured rat neurons

    OpenAIRE

    Yasue Yamada; Kohei Ohtani; Akinori Imajo; Hanae Izu; Hitomi Nakamura; Kohei Shiraishi

    2015-01-01

    These are many volatile organic compounds (VOCs) that are synthesized, produced from petroleum or derived from natural compounds, mostly plants. Fragrant and volatile organic compounds from plants have been used as food additives, medicines and aromatherapy. Several clinical and pathological studies have shown that chronic abuse of VOCs, mainly toluene, causes several neuropsychiatric disorders. Little is known about the mechanisms of neurotoxicity of the solvents. n-Octanal, nonanal, and 2-e...

  8. Simultaneous Microwave Extraction and Separation of Volatile and Non-Volatile Organic Compounds of Boldo Leaves. From Lab to Industrial Scale

    Directory of Open Access Journals (Sweden)

    Loïc Petigny

    2014-04-01

    Full Text Available Microwave extraction and separation has been used to increase the concentration of the extract compared to the conventional method with the same solid/liquid ratio, reducing extraction time and separate at the same time Volatile Organic Compounds (VOC from non-Volatile Organic Compounds (NVOC of boldo leaves. As preliminary study, a response surface method has been used to optimize the extraction of soluble material and the separation of VOC from the plant in laboratory scale. The results from the statistical analysis revealed that the optimized conditions were: microwave power 200 W, extraction time 56 min and solid liquid ratio of 7.5% of plants in water. Lab scale optimized microwave method is compared to conventional distillation, and requires a power/mass ratio of 0.4 W/g of water engaged. This power/mass ratio is kept in order to upscale from lab to pilot plant.

  9. Volatile organic compounds from native potato-associated Pseudomonas as potential anti-oomycete agents.

    Directory of Open Access Journals (Sweden)

    Mout eDeVrieze

    2015-11-01

    Full Text Available The plant kingdom represents a prominent biodiversity island for microbes that associate with the below- or aboveground organs of vegetal species. Both the root and the leaf represent interfaces where dynamic biological interactions influence plant life. Beside well-studied communication strategies based on soluble compounds and protein effectors, bacteria were recently shown to interact both with host plants and other microbial species through the emissions of volatile organic compounds (VOCs. Focusing on the potato late blight-causing agent Phytophthora infestans, this work addresses the potential role of the bacterial volatilome in suppressing plant diseases. In a previous study, we isolated and identified a large collection of strains with anti-Phytophthora potential from both the phyllosphere and the rhizosphere of potato. Here we report the characterization and quantification of their emissions of biogenic volatiles, comparing 16 Pseudomonas strains differing in i origin of isolation (phyllosphere vs. rhizosphere, ii in vitro inhibition of P. infestans growth and sporulation behavior, and iii protective effects against late blight on potato leaf discs. We systematically tested the pharmacological inhibitory activity of core and strain-specific single compounds against P. infestans mycelial growth and sporangial behavior in order to identify key effective candidate molecules present in the complex natural VOCs blends. We envisage the plant bacterial microbiome as a reservoir for functional VOCs and establish the basis for finding the primary enzymatic toolset that enables the production of active components of the volatile bouquet in plant-associated bacteria. Comprehension of these functional interspecies interactions will open perspectives for the sustainable control of plant diseases in forthcoming agriculture.

  10. Volatile Organic Compounds from Native Potato-associated Pseudomonas as Potential Anti-oomycete Agents

    Science.gov (United States)

    De Vrieze, Mout; Pandey, Piyush; Bucheli, Thomas D.; Varadarajan, Adithi R.; Ahrens, Christian H.; Weisskopf, Laure; Bailly, Aurélien

    2015-01-01

    The plant kingdom represents a prominent biodiversity island for microbes that associate with the below- or aboveground organs of vegetal species. Both the root and the leaf represent interfaces where dynamic biological interactions influence plant life. Beside well-studied communication strategies based on soluble compounds and protein effectors, bacteria were recently shown to interact both with host plants and other microbial species through the emissions of volatile organic compounds (VOCs). Focusing on the potato late blight-causing agent Phytophthora infestans, this work addresses the potential role of the bacterial volatilome in suppressing plant diseases. In a previous study, we isolated and identified a large collection of strains with anti-Phytophthora potential from both the phyllosphere and the rhizosphere of potato. Here we report the characterization and quantification of their emissions of biogenic volatiles, comparing 16 Pseudomonas strains differing in (i) origin of isolation (phyllosphere vs. rhizosphere), (ii) in vitro inhibition of P. infestans growth and sporulation behavior, and (iii) protective effects against late blight on potato leaf disks. We systematically tested the pharmacological inhibitory activity of core and strain-specific single compounds against P. infestans mycelial growth and sporangial behavior in order to identify key effective candidate molecules present in the complex natural VOCs blends. We envisage the plant bacterial microbiome as a reservoir for functional VOCs and establish the basis for finding the primary enzymatic toolset that enables the production of active components of the volatile bouquet in plant-associated bacteria. Comprehension of these functional interspecies interactions will open perspectives for the sustainable control of plant diseases in forthcoming agriculture. PMID:26635763

  11. Priority volatile organic compounds in surface waters of the southern North Sea

    International Nuclear Information System (INIS)

    Huybrechts, Tom; Dewulf, Jo; Langenhove, Herman van

    2005-01-01

    The occurrence of 25 volatile organic compounds (VOCs) was studied from April 1998 to October 2000 in the southern North Sea. Target VOCs were selected from lists of priority pollutants for the marine environment and included, e.g., chlorinated short-chain hydrocarbons (CHCs), monocyclic aromatic hydrocarbons (MAHs), and chlorinated monocyclic aromatic hydrocarbons (CMAHs). Water samples were taken from the Channel, the Belgian Continental Shelf, the mouth of the Scheldt estuary and the Southern Bight, and were analysed by purge-and-trap and high-resolution gas chromatography-mass spectrometry. All data were produced by analyses deemed 'in control' by a rigorous quality assurance/quality control program provided by QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe). Chloroform and trichloroethene were commonly detected at concentrations up to 1900 and 270 ng l -1 , respectively. The other CHCs were generally found below 5 ng l -1 , and rarely exceeded 10 ng l -1 . Concentrations of MAHs were at least one order of magnitude higher than those of the CHCs. The higher levels were attributed to anthropogenic emissions from oil-related activities in coastal areas. CMAHs, except chlorobenzene and 1,4-dichlorobenzene, were hardly detected in North Sea waters. The levels of several CHCs and MAHs were shown to decrease compared to previous investigations in 1994-1995, probably as a result of on-going emission reduction efforts. The occurrence of 1,1,1-trichloroethane, for instance, was substantially reduced since the Montreal Protocol was implemented in 1995. - Volatile aromatics are a major group of volatile organic compounds in the North Sea, and are attributed to discharges from shipping and oil related activities

  12. Microbial communities related to volatile organic compound emission in automobile air conditioning units.

    Science.gov (United States)

    Diekmann, Nina; Burghartz, Melanie; Remus, Lars; Kaufholz, Anna-Lena; Nawrath, Thorben; Rohde, Manfred; Schulz, Stefan; Roselius, Louisa; Schaper, Jörg; Mamber, Oliver; Jahn, Dieter; Jahn, Martina

    2013-10-01

    During operation of mobile air conditioning (MAC) systems in automobiles, malodours can occur. We studied the microbial communities found on contaminated heat exchanger fins of 45 evaporators from car MAC systems which were operated in seven different regions of the world and identified corresponding volatile organic compounds. Collected biofilms were examined by scanning electron microscopy and fluorescent in situ hybridization. The detected bacteria were loosely attached to the metal surface. Further analyses of the bacteria using PCR-based single-strand conformation polymorphism and sequencing of isolated 16S rRNA gene fragments identified highly divergent microbial communities with multiple members of the Alphaproteobacteriales, Methylobacteria were the prevalent bacteria. In addition, Sphingomonadales, Burkholderiales, Bacillales, Alcanivorax spp. and Stenotrophomonas spp. were found among many others depending on the location the evaporators were operated. Interestingly, typical pathogenic bacteria related to air conditioning systems including Legionella spp. were not found. In order to determine the nature of the chemical compounds produced by the bacteria, the volatile organic compounds were examined by closed loop stripping analysis and identified by combined gas chromatography/mass spectrometry. Sulphur compounds, i.e. di-, tri- and multiple sulphides, acetylthiazole, aromatic compounds and diverse substituted pyrazines were detected. Mathematical clustering of the determined microbial community structures against their origin identified a European/American/Arabic cluster versus two mainly tropical Asian clusters. Interestingly, clustering of the determined volatiles against the origin of the corresponding MAC revealed a highly similar pattern. A close relationship of microbial community structure and resulting malodours to the climate and air quality at the location of MAC operation was concluded.

  13. Quantitative analysis of volatile organic compounds released and consumed by rat L6 skeletal muscle cells in vitro

    OpenAIRE

    Mochalski, Pawe?; Al-Zoairy, Ramona; Niederwanger, Andreas; Unterkofler, Karl; Amann, Anton

    2014-01-01

    Knowledge of the release of volatile organic compounds (VOCs) by cells provides important information on the origin of VOCs in exhaled breath. Muscle cells are particularly important, since their release of volatiles during the exertion of an effort contributes considerably to breath concentration profiles. Presently, the cultivation of human skeletal muscle cells is encountering a number of obstacles, necessitating the use of animal muscle cells in in vitro studies. Rat L6 skeletal muscle ce...

  14. Car indoor air pollution by volatile organic compounds and aldehydes in Japan

    Directory of Open Access Journals (Sweden)

    Kouichi Tatsu

    2016-06-01

    Full Text Available Fifty-five organic substances including volatile organic compounds (VOCs and aldehydes present in indoor air were measured from 24 car cabins in Japan. A screening-level risk assessment was also performed. Acetaldehyde (3.81–36.0 μg/m3, formaldehyde (3.26–26.7 μg/m3, n-tetradecane (below the method quantification limit (organic compounds originated from the car interior materials. Total volatile organic compound (TVOC concentrations in 14 car cabins (58% of all car cabins exceeded the advisable values established by the Ministry of Health, Labour and Welfare of Japan (400 μg/m3. The highest TVOC concentration (1136 μg/m3 was found in a new car (only one month since its purchase date. Nevertheless, TVOC concentrations exceeded the advisable value even for cars purchased over 10 years ago. Hazard quotients (HQs for formaldehyde obtained using measured median and highest concentrations in both exposure scenarios for occupational use (residential time in a car cabin was assumed to be 8 h were higher than that expected, a threshold indicative of potential adverse effects. Under the same exposure scenarios, HQ values for all other organic compounds remained below this threshold.

  15. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Rodolfo Sosa, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Humberto Bravo, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico)], E-mail: hbravo@servidor.unam.mx; Violeta Mugica, A. [Universidad Autonoma Metropolitana, Azcapotzalco, D.F. (Mexico); Pablo Sanchez, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Emma Bueno, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia (Mexico); Krupa, Sagar [Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 (United States)

    2009-03-15

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City.

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

    Directory of Open Access Journals (Sweden)

    Jianwei Fan

    2017-09-01

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

  17. Metal-organic molecular device for non-volatile memory storage

    International Nuclear Information System (INIS)

    Radha, B.; Sagade, Abhay A.; Kulkarni, G. U.

    2014-01-01

    Non-volatile memory devices have been of immense research interest for their use in active memory storage in powered off-state of electronic chips. In literature, various molecules and metal compounds have been investigated in this regard. Molecular memory devices are particularly attractive as they offer the ease of storing multiple memory states in a unique way and also represent ubiquitous choice for miniaturized devices. However, molecules are fragile and thus the device breakdown at nominal voltages during repeated cycles hinders their practical applicability. Here, in this report, a synergetic combination of an organic molecule and an inorganic metal, i.e., a metal-organic complex, namely, palladium hexadecylthiolate is investigated for memory device characteristics. Palladium hexadecylthiolate following partial thermolysis is converted to a molecular nanocomposite of Pd(II), Pd(0), and long chain hydrocarbons, which is shown to exhibit non-volatile memory characteristics with exceptional stability and retention. The devices are all solution-processed and the memory action stems from filament formation across the pre-formed cracks in the nanocomposite film.

  18. A portable and inexpensive method for quantifying ambient intermediate volatility organic compounds

    Science.gov (United States)

    Bouvier-Brown, Nicole C.; Carrasco, Erica; Karz, James; Chang, Kylee; Nguyen, Theodore; Ruiz, Daniel; Okonta, Vivian; Gilman, Jessica B.; Kuster, William C.; de Gouw, Joost A.

    2014-09-01

    Volatile organic compounds (VOCs) and intermediate volatility VOCs (IVOCs) are gas-phase organic compounds which may participate in chemical reactions affecting air quality and climate. The development of an inexpensive, field-portable quantification method for higher molecular weight VOCs and IVOCs utilizing commercially available components could be used as a tool to survey aerosol precursors or identify and monitor air quality in various communities. We characterized the performance characteristics for the HayeSep-Q adsorbent with a representative selection of anthropogenic and biogenic VOC standards and optimized experimental conditions and procedures for field collections followed by laboratory analysis. All VOCs were analyzed using gas chromatography coupled with mass spectrometry. Precision (average 22%) and accuracy were reasonable and the limit of detection ranged from 10 to 80 pmol/mol (ppt) for the studied compounds. The method was employed at the Los Angeles site during the CalNex campaign in summer 2010 and ambient mixing ratios agreed well (slope 0.69-1.06, R2 0.67-0.71) with measurements made using an in-situ GC-MS - a distinctly different sampling and quantification method. This new technique can be applied to quantify ambient biogenic and anthropogenic C8-C15 VOCs and IVOCs.

  19. Distribution of Total Volatile Organic Compounds at taxi drivers in Tehran

    Directory of Open Access Journals (Sweden)

    Seyyed Mohammad Javad Golhosseini*

    2015-06-01

    Full Text Available Air pollution is currently the most serious environmental health threat worldwide. Volatile Organic Compounds (VOCs are considered as the main effective factors in causing air pollution. Vehicles are among the major sources which emit these compounds, so it seems that automobiles’ microenvironment is one of the places where people are exposed to high concentration of VOC. Evaluating the exposure amount of Total Volatile Organic Compounds (TVOC can indeed be used as an indicator to estimate the amount of exposure to every individual VOC. This study was conducted on the concentration of TVOC inside Tehran taxies for a period of one year. For this purpose, a real time instrument equipped with photo-ionization detector (PID was used. Consequently, the highest and the lowest measured TVOC in taxies equaled 3.33 ppm and 0.72 ppm, respectively. In addition, the arithmetic mean of TVOC concentration was 1.77±0.53 ppm inside the examined taxies. In this study, the parameters like measurement time, climate and vehicle conditions were found to have significant effect on the amount of exposure to TVOC.

  20. Volatile organic chemicals of a shore-dwelling cyanobacterial mat community.

    Science.gov (United States)

    Evans, W G

    1994-02-01

    The main components of a cyanobacterial mat community of a hypersaline lake shore consist of edaphic, mat-forming strains (ecophenes), and littoral strains ofOscillatoria animalis Agardh andO. subbrevis Schmidle, other microorganisms associated with these cyanobacteria, several species ofBembidion (Carabidae: Coleoptera), and two halophytic flowering plants:Puccinellia nuttalliana (salt meadow grass) andSalicornia europaea rubra (samphire). The volatile organic compounds of this community are a blend of those emitted by each of these components such as the C17 alka(e)nes, geosmin, 2-methylisoborneol,β-cyclocitral,β-ionone, dimethyl sulfide, and dimethyl trisulfide of cyanobacteria and associated microorganisms; alcohols, esters, and aldehydes usually associated with flowering plants; and possibly some insect-derived esters, particularly isopropyl tetradecanoate. The dominant compounds were: C11, C13, C15, and C17 alka(e)nes, methyl esters of C16 and C18:2 acids, isopropyl tetradecanoate, heptanal, 3-octanone and 2-nonanone, the acyclic terpene linalool, and the alcohols 1-heptanol, 1-hexanol, 1-octanol, 3-hexen-1-ol, and 2-octen-1-ol. It is concluded that this community may be distinguished from related communities by its repertoire of volatile organic compounds.

  1. Distribution of Total Volatile Organic Compounds at taxi drivers in Tehran

    Directory of Open Access Journals (Sweden)

    Seyyed Mohammad Javad Golhosseini

    2015-06-01

    Full Text Available Air pollution is currently the most serious environmental health threat worldwide. Volatile Organic Compounds (VOC are considered as the main effective factors in causing air pollution. Vehicles are among the major sources which emit these compounds, so it seems that automobiles’ microenvironment is one of the places where people are exposed to high concentration of VOC. Evaluating the exposure amount of Total Volatile Organic Compounds (TVOC can indeed be used as an indicator to estimate the amount of exposure to every individual VOC. This study was conducted on the concentration of TVOC inside Tehran taxies for a period of one year. For this purpose, a real time instrument equipped with photo-ionization detector (PID was used. Consequently, the highest and the lowest measured TVOC in taxies equaled 3.33 ppm and 0.72 ppm, respectively. In addition, the arithmetic mean of TVOC concentration was 1.77±0.53 ppm inside the examined taxies. In this study, the parameters like measurement time, climate and vehicle conditions were found to have significant effect on the amount of exposure to TVOC.

  2. Environment and Pollution Management of Pollution Volatile Organic Compounds in Cluj-Napoca

    Directory of Open Access Journals (Sweden)

    Carmen Florean

    2016-10-01

    Full Text Available Pollution negative influences the environmental, human health, buildings and increase the production of waste. We are currently witnessing pollution and degradation in some cases irreversible, of the environment. Environmental issues are extremely complex and cover all sectors. Worldwide, industrial pollution strategies necessary to reduce emissions to the atmosphere hydrocarbons, volatile organic compounds (VOCs and other polluants in urban areas. The highest concentrations of volatile organic compounds of more than 80 mg/m3 occur in densely populated areas. The latest data reported in the residential area of Cluj-Napoca values did not exceed 20 m /m3. However peaks reported VOC concentrations, depending on the season, exceeding the upper limit that according to Law. 104/2011 is 75 μ/m3. It was identified due to increase annual mean concentration of VOCs as, in particular, road traffic exceeding sanitary standards on the main traffic routes within the city. In this paper the results obtained after carrying out an analysis of the average VOC concentration recorded in the city Cluj-Napoca as a result of car traffic. They were pursued average concentrations of VOCs resulting from the combustion of liquid fuels, petrol and diesel type. Analyzing the results obtained are proposed solutions for reducing VOC emissions. The rule under which these solutions have been proposed to reduce the concentration of VOCs took into account the possibility implementation and maintenance costs thereof.

  3. Characterization of hydrophobic hypercrosslinked polymer as an adsorbent for removal of chlorinated volatile organic compounds.

    Science.gov (United States)

    Long, Chao; Liu, Peng; Li, Ying; Li, Aimin; Zhang, Quanxing

    2011-05-15

    A hydrophobic hypercrosslinked polymer with poly (4-tert-butylstyrene-styrene-divinylbenzene) matrix (LC-1) was prepared as adsorbent for the removal of volatile organic compounds from gas streams. The content of oxygen-containing functional groups of LC-1 was about one-fourth that of commercial hypercrosslinked polymeric adsorbent (NDA-201). The results of the water vapor adsorption experiment indicated that LC-1 had a more hydrophobic surface than NDA-201. Three chlorinated volatile organic compounds (trichloroethylene, trichloromethane, and 1, 2-dichloroethane) were used to investigate the adsorption characteristics of LC-1 under dry and humid conditions. Equilibrium adsorption data in dry streams showed that LC-1 had good adsorption abilities for three chlorinated VOCs due to its abundant micropore structure. Moreover, the presence of water vapor in the gas stream had negligible effect on breakthrough time of three chlorinated VOCs adsorption onto LC-1 when values of relative humidity were equal to or below 50%; the breakthrough time of three chlorinated VOCs decreased less than 11% even if the relative humidity was 90%. Taken together, it is expected that LC-1 would be a promising adsorbent for the removal of VOCs vapor from the humid gas streams.

  4. Research on release rate of volatile organic compounds in typical vessel cabin

    Directory of Open Access Journals (Sweden)

    ZHANG Jinlan

    2018-02-01

    Full Text Available [Objectives] Volatile Organic Compounds (VOC should be efficiently controlled in vessel cabins to ensure the crew's health and navigation safety. As an important parameter, research on release rate of VOCs in cabins is required. [Methods] This paper develops a method to investigate this parameter of a ship's cabin based on methods used in other closed indoor environments. A typical vessel cabin is sampled with Tenax TA tubes and analyzed by Automated Thermal Desorption-Gas Chromatography-Mass Spectrometry (ATD-GC/MS. The lumped mode is used and the release rate of Benzene, Toluene, Ethylbenzene and Xylene (BTEX, the typical representatives of VOCs, is obtained both in closed and ventilated conditions. [Results] The results show that the content of xylene and Total Volatile Organic Compounds (TVOC exceed the indoor environment standards in ventilated conditions. The BTEX release rate is similar in both conditions except for the benzene. [Conclusions] This research builds a method to measure the release rate of VOCs, providing references for pollution character evaluation and ventilation and purification system design.

  5. The Venus flytrap attracts insects by the release of volatile organic compounds

    Science.gov (United States)

    Kreuzwieser, Jürgen; Honsel, Anne

    2014-01-01

    Does Dionaea muscipula, the Venus flytrap, use a particular mechanism to attract animal prey? This question was raised by Charles Darwin 140 years ago, but it remains unanswered. This study tested the hypothesis that Dionaea releases volatile organic compounds (VOCs) to allure prey insects. For this purpose, olfactory choice bioassays were performed to elucidate if Dionaea attracts Drosophila melanogaster. The VOCs emitted by the plant were further analysed by GC-MS and proton transfer reaction-mass spectrometry (PTR-MS). The bioassays documented that Drosophila was strongly attracted by the carnivorous plant. Over 60 VOCs, including terpenes, benzenoids, and aliphatics, were emitted by Dionaea, predominantly in the light. This work further tested whether attraction of animal prey is affected by the nutritional status of the plant. For this purpose, Dionaea plants were fed with insect biomass to improve plant N status. However, although such feeding altered the VOC emission pattern by reducing terpene release, the attraction of Drosophila was not affected. From these results it is concluded that Dionaea attracts insects on the basis of food smell mimicry because the scent released has strong similarity to the bouquet of fruits and plant flowers. Such a volatile blend is emitted to attract insects searching for food to visit the deadly capture organ of the Venus flytrap. PMID:24420576

  6. Characterization of polar compounds and oligomers in secondary organic aerosol using liquid chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Hamilton, Jacqueline F; Lewis, Alastair C; Carey, Trevor J; Wenger, John C

    2008-01-15

    A generic method has been developed for the analysis of polar compounds and oligomers in secondary organic aerosol (SOA) formed during atmospheric simulation chamber experiments. The technique has been successfully applied to SOA formed in a variety of systems, ranging from ozonolysis of biogenic volatile organic compounds to aromatic photooxidation. An example application of the method is described for the SOA produced from the reaction of ozone with cis-3-hexenyl acetate, an important biogenic precursor. A range of solvents were tested as extraction media, and water was found to yield the highest recovery. Extracts were analyzed using reversed-phase liquid chromatography coupled to ion trap mass spectrometry. In order to determine correct molecular weight assignments and increase sensitivity for less polar species, a series of low-concentration mobile-phase additives were used (NaCl, LiBr, NH4OH). Lithium bromide produced better fragmentation patterns, with more structural information than in the other cases with no reduction in sensitivity. The main reaction products identified in the particle-phase were 3-acetoxypropanal, 3-acetoxypropanoic acid, and 3-acetoxypropane peroxoic acid and a series of dimers and trimers up to 500 Da. Structural identification of oligomers indicates the presence of linear polyesters possibly formed via esterfication reactions or decomposition of peroxyhemiacetals.

  7. Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature

    Science.gov (United States)

    Lawrence, Stephen J.

    2006-01-01

    This report provides abridged information describing the most salient properties and biodegradation of 27 chlorinated volatile organic compounds detected during ground-water studies in the United States. This information is condensed from an extensive list of reports, papers, and literature published by the U.S. Government, various State governments, and peer-reviewed journals. The list includes literature reviews, compilations, and summaries describing volatile organic compounds in ground water. This report cross-references common names and synonyms associated with volatile organic compounds with the naming conventions supported by the International Union of Pure and Applied Chemistry. In addition, the report describes basic physical characteristics of those compounds such as Henry's Law constant, water solubility, density, octanol-water partition (log Kow), and organic carbon partition (log Koc) coefficients. Descriptions and illustrations are provided for natural and laboratory biodegradation rates, chemical by-products, and degradation pathways.

  8. Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

    Science.gov (United States)

    Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

    2012-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC

  9. Distribution of enantiomers of volatile organic compounds in selected fruit distillates.

    Science.gov (United States)

    Vyviurska, Olga; Zvrškovcová, Helena; Špánik, Ivan

    2017-01-01

    The enantiomer ratios of chiral volatile organic compounds in fruit distillates were determined by multidimensional gas chromatography using solid-phase microextraction (SPME) as a sample treatment procedure. Linalool and its oxides, limonene, α-terpineol, and nerolidol, were present at the highest concentration levels, while significantly lower amounts of β-citronellol and lactones were found in the studied samples. However, almost all terpenoids mainly occur as a racemic or near-racemic mixture; enantiomer distribution of some chiral organic compounds in fruit distillates correlated to a botanical origin. In particular, a significant enantiomeric excess of (R)-linalool and (S)-α-terpineol was found only for pear brandy, and likewise the dominance (R)-limonene and the second eluted enantiomer of nerolidol for Sorbus domestica and strawberry, respectively. The distribution of γ-lactones stereoisomers was more nonspecific, with a general excess of the R-enantiomer. © 2016 Wiley Periodicals, Inc.

  10. Evolution and kinetics of volatile organic compounds generated during low-temperature polymer degradation.

    Science.gov (United States)

    Xiang, Qin; Mitra, Somenath; Xanthos, Marino; Dey, Subir K

    2002-01-01

    A method using direct flame ionization detector (FID) measurement was developed to study total volatile organic compound (VOC) emissions during thermal degradation of polymers. This method was used to estimate organic emissions from different polymers, such as low-density polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and commingled postconsumer streams, such as recycled carpet residue and auto shredder residue (ASR). The effects of process parameters, such as temperature, heating rate, and residence time, were also studied. Significant VOC emissions were observed at normal processing temperatures, particularly from recycled polymers. Each polymer showed a distinct evolution pattern during its thermal degradation. The kinetics of VOC emissions were also studied using a nonisothermal technique. The kinetic parameters were in agreement with data from the literature.

  11. Arctic Vegetation under Climate Change – Biogenic Volatile Organic Compound Emissions and Leaf Anatomy

    DEFF Research Database (Denmark)

    Schollert, Michelle

    common arctic plant species, illustrating the great importance of vegetation composition for determining ecosystem BVOC emissions. Additionally, this thesis assesses the BVOC emission responses in common arctic plant species to effects of climate change: warming, shading and snow addition. Against...... treatment effects on BVOC emissions. Furthermore, the anatomy of arctic plants seems to respond differently to warming than species at lower latitudes. The results in this thesis demonstrate the complexity of the effects of climate change on BVOC emissions and leaf anatomy of arctic plant species......Biogenic volatile organic compounds (BVOCs) emitted from terrestrial vegetation are highly reactive non-methane hydrocarbons which participate in oxidative reactions in the atmosphere prolonging the lifetime of methane and contribute to the formation of secondary organic aerosols. The BVOC...

  12. Air ionization as a control technology for off-gas emissions of volatile organic compounds.

    Science.gov (United States)

    Kim, Ki-Hyun; Szulejko, Jan E; Kumar, Pawan; Kwon, Eilhann E; Adelodun, Adedeji A; Reddy, Police Anil Kumar

    2017-06-01

    High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO 2 and H 2 O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O 3 ). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O 3 , NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management. Copyright © 2017. Published by Elsevier Ltd.

  13. Volatile organic compounds and trace metal level in some beers collected from Romanian market

    Science.gov (United States)

    Voica, Cezara; Kovacs, Melinda; Vadan, Marius

    2013-11-01

    Beer is one of the most popular beverages at worldwide level. Through this study fifteen different types of beer collected from Romanian market were analysed in order to evaluate their mineral, trace element as well the their organic content. Importance of such characterization of beer samples is supported by the fact that their chemical composition can affect both taste and stability of beer, as well the consumer health. Minerals and trace elements analysis were performed on ICP-MS while organic compounds analysis was done through GC-MS. Through ICP-MS analysis, elements as Ca, Na, K and Mg were evidenced at mgṡkg-1 order while elements as Cr, Ba, Co, Ni were detected at lower level. After GC-MS analysis the major volatile compounds that were detected belong to alcohols namely ethanol, propanol, isobutanol, isoamyl alcohol and linalool. Selected fatty acids and esters were evidenced also in the studied beer samples.

  14. Evaluation of the Effect of Two Volatile Organic Compounds on Barley Pathogens

    Directory of Open Access Journals (Sweden)

    Amine Kaddes

    2016-08-01

    Full Text Available This study aimed to determine the effect of Volatile Organic Compounds (VOCs on some pathogens, these VOCs were emitted during interactions of barley with Fusarium culmorum Schltdl and/or Cochliobolus sativus Shoemaker, two common root rot pathogens. Our work shows that two organic esters: methyl propanoate (MP and methyl prop-2-enoate (MA significantly reduced the development of fungi in vitro. Additional tests showed that the esters significantly inhibited spore germination of these pathogens. The activity of these VOCs on a wide range of fungal and bacterial pathogens was also tested in vitro and showed inhibitory action. The effect of the VOCs on infected barley seeds also showed plantlets growing without disease symptoms. MA and MP seem to have potential value as alternative plant protection compounds against barley bioagressors.

  15. Detection of Volatile Organic Compound Gas Using Localized Surface Plasmon Resonance of Gold Nanoparticles

    International Nuclear Information System (INIS)

    Sri Nengsih; Akrajas Ali Umar; Muhamad Mat Salleh; Muhammad Yahaya

    2011-01-01

    This paper reports on the detection of several organic vapors using the unique characteristic of localized surface plasmon resonance (LSPR) gold nanoparticles. Gold nanoparticles on quartz substrate were prepared using seed mediated growth method. In a typical process, gold nanoparticles with average size ca. 36 nm were obtained to densely grown on the substrate. Detection of gas was based on the change in the LSPR of the gold nanoparticles film upon the exposure to the gas sample. It was found that gold nanoparticles were sensitive to the presence of volatile organic compound (VOC) gas from the change in the surface plasmon resonance (SPR) intensity. The mechanism for the detection of VOCs gas will be discussed. (author)

  16. Active atmosphere-ecosystem exchange of the vast majority of detected volatile organic compounds.

    Science.gov (United States)

    Park, J-H; Goldstein, A H; Timkovsky, J; Fares, S; Weber, R; Karlik, J; Holzinger, R

    2013-08-09

    Numerous volatile organic compounds (VOCs) exist in Earth's atmosphere, most of which originate from biogenic emissions. Despite VOCs' critical role in tropospheric chemistry, studies for evaluating their atmosphere-ecosystem exchange (emission and deposition) have been limited to a few dominant compounds owing to a lack of appropriate measurement techniques. Using a high-mass resolution proton transfer reaction-time of flight-mass spectrometer and an absolute value eddy-covariance method, we directly measured 186 organic ions with net deposition, and 494 that have bidirectional flux. This observation of active atmosphere-ecosystem exchange of the vast majority of detected VOCs poses a challenge to current emission, air quality, and global climate models, which do not account for this extremely large range of compounds. This observation also provides new insight for understanding the atmospheric VOC budget.

  17. Modeling long-term uptake and re-volatilization of semi-volatile organic compounds (SVOCs) across the soil-atmosphere interface.

    Science.gov (United States)

    Bao, Zhongwen; Haberer, Christina; Maier, Uli; Beckingham, Barbara; Amos, Richard T; Grathwohl, Peter

    2015-12-15

    Soil-atmosphere exchange is important for the environmental fate and atmospheric transport of many semi-volatile organic compounds (SVOCs). This study focuses on modeling the vapor phase exchange of semi-volatile hydrophobic organic pollutants between soil and the atmosphere using the multicomponent reactive transport code MIN3P. MIN3P is typically applied to simulate aqueous and vapor phase transport and reaction processes in the subsurface. We extended the code to also include an atmospheric boundary layer where eddy diffusion takes place. The relevant processes and parameters affecting soil-atmosphere exchange were investigated in several 1-D model scenarios and at various time scales (from years to centuries). Phenanthrene was chosen as a model compound, but results apply for other hydrophobic organic compounds as well. Gaseous phenanthrene was assumed to be constantly supplied to the system during a pollution period and a subsequent regulation period (with a 50% decline in the emission rate). Our results indicate that long-term soil-atmosphere exchange of phenanthrene is controlled by the soil compartment - re-volatilization thus depends on soil properties. A sensitivity analysis showed that accumulation and transport in soils in the short term is dominated by diffusion, whereas in the long term groundwater recharge and biodegradation become relevant. As expected, sorption causes retardation and slows down transport and biodegradation. If atmospheric concentration is reduced (e.g. after environmental regulations), re-volatilization from soil to the atmosphere occurs only for a relatively short time period. Therefore, the model results demonstrate that soils generally are sinks for atmospheric pollutants. The atmospheric boundary layer is only relevant for time scales of less than one month. The extended MIN3P code can also be applied to simulate fluctuating concentrations in the atmosphere, for instance due to temperature changes in the topsoil. Copyright

  18. Gas-shell-encapsulation of Activated Carbon to Reduce Fouling and Increase the Efficacy of Volatile Organic Compound Removal

    NARCIS (Netherlands)

    Poortinga, Albert T.; Rijn, van Cees J.M.

    2017-01-01

    A method to encapsulate activated carbon particles is presented that reduces fouling of these particles with Natural Organic Matter (NOM) to preserve their adsorption capacity for Volatile Organic Compounds (VOCs) from water in the presence of NOM. The encapsulation method uses an oil-in-water

  19. Growth promotion of Lactuca sativa in response to volatile organic compounds emitted from diverse bacterial species.

    Science.gov (United States)

    Fincheira, Paola; Venthur, Herbert; Mutis, Ana; Parada, Maribel; Quiroz, Andrés

    2016-12-01

    Agrochemicals are currently used in horticulture to increase crop production. Nevertheless, their indiscriminate use is a relevant issue for environmental and legal aspects. Alternative tools for reducing fertilizers and synthetic phytohormones are being investigated, such as the use of volatile organic compounds (VOCs) as growth inducers. Some soil bacteria, such as Pseudomonas and Bacillus, stimulate Arabidopsis and tobacco growth by releasing VOCs, but their effects on vegetables have not been investigated. Lactuca sativa was used as model vegetable to investigate bacterial VOCs as growth inducers. We selected 10 bacteria strains, belonging to Bacillus, Staphylococcus and Serratia genera that are able to produce 3-hydroxy-2-butanone (acetoin), a compound with proven growth promoting activity. Two-day old-seedlings of L. sativa were exposed to VOCs emitted by the selected bacteria grown in different media cultures for 7 days. The results showed that the VOCs released from the bacteria elicited an increase in the number of lateral roots, dry weight, root growth and shoot length, depending on the media used. Three Bacillus strains, BCT53, BCT9 and BCT4, were selected according to its their growth inducing capacity. The BCT9 strain elicited the greatest increases in dry weight and primary root length when L. sativa seedlings were subjected to a 10-day experiment. Finally, because acetoin only stimulated root growth, we suggest that other volatiles could be responsible for the growth promotion of L. sativa. In conclusion, our results strongly suggest that bacteria volatiles can be used as growth-inducers as alternative or complementary strategies for application in horticulture species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. Determination of heat purgeable and ambient purgeable volatile organic compounds in water by gas chromatography/mass spectrometry

    Science.gov (United States)

    Rose, Donna L.; Sandstrom, Mark W.; Murtagh, Lucinda K.

    2016-09-08

    Two new analytical methods have been developed by the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) that allow the determination of 37 heat purgeable volatile organic compounds (VOCs) (USGS Method O-4437-16 [NWQL Laboratory Schedule (LS) 4437]) and 49 ambient purgeable VOCs (USGS Method O-4436-16 [NWQL LS 4436]) in unfiltered water. This report documents the procedures and initial performance of both methods. The compounds chosen for inclusion in the methods were determined as having high priority by the USGS National Water-Quality Assessment (NAWQA) Program. Both methods use a purge-and-trap technique with gas chromatography/mass spectrometry. The compounds are extracted from the sample by bubbling helium through a 25-milliliter sample. For the polar and less volatile compounds, the sample is heated at 60 degrees Celsius, whereas the less polar and more volatile compounds are purged using a separate analytical procedure at ambient temperature. The compounds are trapped on a sorbent trap, desorbed into a gas chromatograph/mass spectrometer for separation, and then identified and quantified. Sample preservation is recommended for both methods by adding a 1:1 solution of hydrochloric acid (HCl [1:1]) to water samples to adjust the pH to 2. Analysis within 14 days from sampling is recommended.The heat purgeable method (USGS Method O-4437-16) operates with the mass spectrometer in the simultaneous full scan/selected ion monitoring mode. This method supersedes USGS Method O-4024-03 (NWQL LS 4024). Method detection limits (MDLs) for fumigant compounds 1,2-dibromoethane, 1,2-dichloropropane, 1,2,3-trichloropropane, chloropicrin, and 1,2-dibromo-3-chloropropane range from 0.002 to 0.010 microgram per liter (µg/L). The MDLs for all remaining heat purgeable VOCs range from 0.006 µg/L for tert-butyl methyl ether to 3 µg/L for alpha-terpineol. Calculated holding times indicate that 36 of the 37 heat purgeable VOCs are stable for a minimum of 14 days

  1. A numerical solution to three-dimensional multiphase transport of volatile organic compounds in unsaturated soils -- with an application to the remedial method of in-situ volatilization

    International Nuclear Information System (INIS)

    Filley, T.; Tomasko, D.

    1992-04-01

    Part I of this paper presents the development and application of a numerical model for determining the fate and transport of volatile organic compounds (VOCS) in the unsaturated zone resulting from forced volatilization and gaseous advection-dispersion of organic vapor in a multipartitioned three-dimensional environment. The model allows for single-component transport in the gas and water phases. The hydrocarbon is assumed to be in specific retention and, therefore, immobile. Partitioning of the hydrocarbon between the oil, water, gas, and soil is developed as rate-limited functions that are incorporated into sink/source terms in the transport equations. The code for the model was developed specifically to investigate in-situ volatilization (ISV) remedial strategies, predict the extent of cleanup from information obtained at a limited number of measurement locations, and to help design ISV remedial systems. Application of the model is demonstrated for a hypothetical one-dimensional ISV system. Part II of this paper will present the analysis of an existing ISV system using the full three-dimensional capability of the model

  2. Development of multicomponent parts-per-billion-level gas standards of volatile toxic organic compounds

    International Nuclear Information System (INIS)

    Rhoderick, G.C.; Zielinski, W.L. Jr.

    1990-01-01

    This paper reports that the demand for stable, low-concentration multicomponent standards of volatile toxic organic compounds for quantifying national and state measurement of ambient air quality and hazardous waste incineration emissions has markedly increased in recent years. In response to this demand, a microgravimetric technique was developed and validated for preparing such standards; these standards ranged in concentration from several parts per million (ppm) down to one part per billion (ppb) and in complexity from one organic up to 17. Studies using the gravimetric procedure to prepare mixtures of different groups of organics. including multi-components mixtures in the 5 to 20 ppb range, revealed a very low imprecision. This procedure is based on the separate gravimetric introduction of individual organics into an evacuated gas cylinder, followed by the pressurized addition of a precalculated amount of pure nitrogen. Additional studies confirmed the long-term stability of these mixtures. The uncertainty of the concentrations of the individual organics at the 95% confidence level ranged from less than 1% relative at 1 ppm to less than 10% relative at 1 ppb. Over 100 primary gravimetric standards have been developed, validated, and used for certifying the concentrations of a variety of mixtures for monitoring studies

  3. Phytotoxic and antimicrobial activity of volatile and semi-volatile organic compounds from the endophyte Hypoxylon anthochroum strain Blaci isolated from Bursera lancifolia (Burseraceae).

    Science.gov (United States)

    Ulloa-Benítez, Á; Medina-Romero, Y M; Sánchez-Fernández, R E; Lappe-Oliveras, P; Roque-Flores, G; Duarte Lisci, G; Herrera Suárez, T; Macías-Rubalcava, M L

    2016-08-01

    To evaluate the phytotoxic, antifungal and antioomycete activity; and, determine the chemical composition of the volatile organic compounds (VOCs) and semi-volatile metabolites produced by the endophyte Hypoxylon anthochroum strain Blaci isolated from Bursera lancifolia. Based on its macro- and micro-morphological features, the strain Blaci was identified as Nodulisporium sp.; partial analysis of its ITS1-5.8-ITS2 ribosomal gene sequence revealed the identity of the teleomorphic stage of the fungus as H. anthochroum. Phytotoxic and antimicrobial activities of VOCs, and culture medium and mycelium organic extracts from H. anthochroum Blaci were determined by simple and multiple antagonism bioassays, and gas phase and agar dilution bioassays respectively. The volatile and semi-volatile metabolites were identified by gas chromatography-mass spectrometry. VOCs from a 5-day H. anthochroum strain Blaci culture caused the inhibition of seed germination, root elongation and seedling respiration on Amaranthus hypochondriacus, Panicum miliaceum, Trifolium pratense and Medicago sativa. In addition, extracts, phenylethyl alcohol and eucalyptol main compounds present in the VOCs and extract displayed a high phytotoxic activity, inhibiting the three physiological processes on the four test plants in a concentration-dependent manner. The results revealed that H. anthochroum strain Blaci produces a mixture of VOCs. These VOCs showed a strong phytotoxic activity on seed germination, root elongation, and seedling respiration of four plants and slightly affected the growth of phytopathogenic fungi and oomycetes. Also, the culture medium and mycelium extracts of H. anthochroum showed a high phytotoxic activity on the four test plants and, generally, the culture medium extract was more phytotoxic than the mycelium extracts. This work firstly reports the phytotoxic activity of volatile and semi-volatile compounds produced by the endophyte H. anthochroum strain Blaci on seed

  4. Volatile organic compounds and secondary organic aerosol in the Earth's atmosphere

    International Nuclear Information System (INIS)

    Galbally, Ian

    2007-01-01

    Full text: Recent research, when considered as a whole, suggests that a substantial fraction of both gas-phase and aerosol atmospheric organics have not been, or have very rarely been, directly measured. A review of the global budget for organic gases shows that we cannot account for the loss of approximately half the non-methane organic carbon entering the atmosphere. We suggest that this unaccounted-for loss most likely occurs through formation of secondary organic aerosols (SOAs), indicating that the source for these aerosols is an order of magnitude larger than current estimates. There is evidence that aged secondary organic aerosol can participate in both direct and indirect (cloud modifying) radiative forcing and that this influence may change with other global climate change. Even though our knowledge of the organic composition of the atmosphere is limited, these compounds clearly influence the reactive chemistry of the atmosphere and the formation, composition, and climate impact of aerosols A major challenge in the coming decade of atmospheric chemistry research will be to elucidate the sources, structure, chemistry, fate and influences of these clearly ubiquitous yet poorly constrained organic atmospheric constituents

  5. Measurements of oxygenated volatile organic compounds in the oil sands region of Alberta

    Science.gov (United States)

    Moussa, S. G.; Leithead, A.; Li, S. M.; Gordon, M.; Hayden, K. L.; Wang, D. K.; Staebler, R. M.; Liu, P.; O'Brien, J.; Mittermeier, R.; Liggio, J.

    2014-12-01

    Oxygenated volatile organic compounds (OVOCs) are ubiquitous in the atmosphere, and represent an important fraction of volatile organic compounds. Additionally some OVOC species may pose health risks. OVOCs can affect the oxidative and radiative budget of the atmosphere since they are precursors to ground level ozone, hydroxyl radicals and secondary organic aerosols (SOA). OVOCs such as methanol, formaldehyde, acetaldehyde, acetone, crotonaldehyde, methylvinylketone (MVK), methylethylketone (MEK) and acrolein can be emitted from anthropogenic and biogenic sources. Additionally, they are the secondary products of the photo-oxidation of hydrocarbons (biogenic and anthropogenic). Understanding the magnitude of these sources is a prerequisite for accurate representations of radical cycling, ozone production and SOA formation in air quality models. The sources of OVOCs in the Alberta Oil Sands (OS) region have not previously been well characterized. In the summer of 2013, airborne measurements of various OVOCs were made in the Athabasca oil sands region between August 13 and September 7, 2013. Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) was used to measure methanol, formaldehyde, acetaldehyde, acetone, crotonaldehyde, MVK, MEK, acrolein as well as other hydrocarbons. Emission ratios (ER) for several OVOCs (relative to carbon monoxide; CO) were used to estimate direct anthropogenic emissions from OS industrial sources, while the calculated OH radical exposures were used to estimate the production and removal of secondary anthropogenic OVOCs. The results indicate that OVOCs such as acetaldehyde, crotonaldehyde and MVK have both primary and secondary anthropogenic and biogenic sources. However, species such as methanol and acrolein are from biogenic and anthropogenic sources, respectively. The results of this work will help to characterize sources of OVOCs and the factors influencing their atmospheric fate in the Oil Sands region.

  6. Leaf level emissions of volatile organic compounds (VOC from some Amazonian and Mediterranean plants

    Directory of Open Access Journals (Sweden)

    A. Bracho-Nunez

    2013-09-01

    Full Text Available Emission inventories defining regional and global biogenic volatile organic compounds (VOC emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity and physics (secondary organic aerosol formation and effects. The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene < limonene < sabinene < ß-pinene. Mediterranean plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed

  7. Impact of elevated CO2 and O3 concentrations on biogenic volatile organic compounds emissions from Ginkgo biloba.

    Science.gov (United States)

    Li, Dewen; Chen, Ying; Shi, Yi; He, Xingyuan; Chen, Xin

    2009-04-01

    In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 microg g(-1) h(-1) in July, and 0.92 microg g(-1) h(-1) in September. Isoprene and limonene were the most abundant detected compounds. In September, alpha-pinene accounted for 22.5% of the total. Elevated CO(2) concentration in OTCs increased isoprene emission significantly in July (pemission was enhanced in July and decreased in September by elevated CO(2). Exposed to elevated O(3) increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 microg g(-1) h(-1) (in July) and 2.24 microg g(-1) h(-1) (in September), respectively. The combination of elevated CO(2) and O(3) did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Delta3-carene in September.

  8. Sugar-Based Polyamides: Self-Organization in Strong Polar Organic Solvents.

    Science.gov (United States)

    Rosu, Cornelia; Russo, Paul S; Daly, William H; Cueto, Rafael; Pople, John A; Laine, Roger A; Negulescu, Ioan I

    2015-09-14

    Periodic patterns resembling spirals were observed to form spontaneously upon unassisted cooling of d-glucaric acid- and d-galactaric acid-based polyamide solutions in N-methyl-N-morpholine oxide (NMMO) monohydrate. Similar observations were made in d-galactaric acid-based polyamide/ionic liquid (IL) solutions. The morphologies were investigated by optical, polarized light and confocal microscopy assays to reveal pattern details. Differential scanning calorimetry was used to monitor solution thermal behavior. Small- and wide-angle X-ray scattering data reflected the complex and heterogeneous nature of the self-organized patterns. Factors such as concentration and temperature were found to influence spiral dimensions and geometry. The distance between rings followed a first-order exponential decay as a function of polymer concentration. Fourier-Transform Infrared Microspectroscopy analysis of spirals pointed to H-bonding between the solvent and the pendant hydroxyl groups of the glucose units from the polymer backbone. Tests on self-organization into spirals of ketal-protected d-galactaric acid polyamides in NMMO monohydrate confirmed the importance of the monosaccharide's pendant free hydroxyl groups on the formation of these patterns. Rheology performed on d-galactaric-based polyamides at high concentration in NMMO monohydrate solution revealed the optimum conditions necessary to process these materials as fibers by spinning. The self-organization of these sugar-based polyamides mimics certain biological materials.

  9. Determination of volatile organic compounds responsible for flavour in cooked river buffalo meat

    Directory of Open Access Journals (Sweden)

    A. Di Luccia

    2010-02-01

    Full Text Available Flavour is an important consumer attractive that directly influences the success of food products on the market. The determination of odorous molecules and their identification allows to useful knowledge for producers to valorise their own products. Buffalo meat has a different chemical composition from pork and beef and requires some cautions in cooking and processing. This work aims at the identification of volatile molecules responsible for flavours in river buffalo meat. The determination was carried out by solid phase micro-extraction (SPME technique and analysed by gas chromatography coupled to mass spectrometry (GC-MS. The most relevant results were the higher odorous impact of buffalo meat and the higher content of sulphide compounds responsible for wild aroma respect to pork and beef. These results were obtained comparing the total area of peaks detected in every chromatogram. We have also found significant differences concerning the contents of pentadecane, 1-hexanol-2 ethyl, butanoic acid, furano-2-penthyl. The origin of volatile organic compounds and their influence on the river buffalo aromas were discussed.

  10. Influence of volatile organic compounds emitted by Pseudomonas and Serratia strains on Agrobacterium tumefaciens biofilms.

    Science.gov (United States)

    Plyuta, Vladimir; Lipasova, Valentina; Popova, Alexandra; Koksharova, Olga; Kuznetsov, Alexander; Szegedi, Erno; Chernin, Leonid; Khmel, Inessa

    2016-07-01

    The ability to form biofilms plays an important role in bacteria-host interactions, including plant pathogenicity. In this work, we investigated the action of volatile organic compounds (VOCs) produced by rhizospheric strains of Pseudomonas chlororaphis 449, Pseudomonas fluorescens B-4117, Serratia plymuthica IC1270, as well as Serratia proteamaculans strain 94, isolated from spoiled meat, on biofilms formation by three strains of Agrobacterium tumefaciens which are causative agents of crown-gall disease in a wide range of plants. In dual culture assays, the pool of volatiles emitted by the tested Pseudomonas and Serratia strains suppressed the formation of biofilms of A. tumefaciens strains grown on polycarbonate membrane filters and killed Agrobacterium cells in mature biofilms. The individual VOCs produced by the tested Pseudomonas strains, that is, ketones (2-nonanone, 2-heptanone, 2-undecanone), and dimethyl disulfide (DMDS) produced by Serratia strains, were shown to kill A. tumefaciens cells in mature biofilms and suppress their formation. The data obtained in this study suggest an additional potential of some ketones and DMDS as protectors of plants against A. tumefaciens strains, whose virulence is associated with the formation of biofilms on the infected plants. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  11. Quantitative determination of volatile organic compounds in indoor dust using gas chromatography-UV spectrometry.

    Science.gov (United States)

    Nilsson, Anders; Lagesson, Verner; Bornehag, Carl-Gustaf; Sundell, Jan; Tagesson, Christer

    2005-10-01

    A novel technique, gas chromatography-UV spectrometry (GC-UV), was used to quantify volatile organic compounds (VOCs) in settled dust from 389 residences in Sweden. The dust samples were thermally desorbed in an inert atmosphere and evaporated compounds were concentrated by solid phase micro extraction and separated by capillary GC. Eluting compounds were then detected, identified, and quantified using a diode array UV spectrophotometer. Altogether, 28 compounds were quantified in each sample; 24 of these were found in more than 50% of the samples. The compounds found in highest concentrations were saturated aldehydes (C5-C10), furfuryl alcohol, 2,6-di-tert-butyl-4-methylphenol (BHT), 2-furaldehyde, and benzaldehyde. Alkenals were also found, notably 2-butenal (crotonaldehyde), 2-methyl-propenal (methacrolein), hexenal, heptenal, octenal, and nonenal. The concentrations of each of the 28 compounds ranged between two to three orders of magnitude, or even more. These results demonstrate the presence of a number of VOCs in indoor dust, and provide, for the first time, a quantitative determination of these compounds in a larger number of dust samples from residents. The findings also illustrate the potential use of GC-UV for analysing volatile compounds in indoor dust, some of which are potential irritants (to the skin, eyes or respiratory system) if present at higher concentrations. The potential use of GC-UV for improving survey and control of the human exposure to particle-bound irritants and other chemicals is inferred.

  12. Multipass membrane air-stripping (MAS) for removing volatile organic compounds (VOCs) from surfactant micellar solutions.

    Science.gov (United States)

    Cheng, Hefa; Hu, Yuanan; Luo, Jian; Sabatini, David A

    2009-10-30

    Air-stripping is one of the most effective technologies for removing volatile organic compounds (VOCs) from surfactant solutions, although the presence of surfactant poses some unique challenges. This study evaluated the effect of a mixed surfactant system on the apparent Henry's law constant of tetrachloroethylene (PCE) and the efficiency of PCE removal from surfactant solutions using a lab-scale hollow fiber membrane contactor. Results show that the presence of surfactant significantly reduced the apparent Henry's law constant of PCE, and the reduction was proportional to the total surfactant concentration. PCE removal efficiency by membrane air-stripping (MAS) decreased as the surfactant system transitioned from solubilization to supersolubilization. Besides significantly reducing the apparent volatility of VOCs, the presence of surfactant brings additional mass transfer resistance in air-stripping, which makes it difficult to achieve high levels of contaminant removal, even at very high air/liquid (A/L) ratios. In contrast, multipass/multistage MAS operated at low A/L ratios could achieve near 100% contaminant removal because of less mass transfer limitation during each stripping pass/stage. Experimental results, together with model calculations demonstrate multipass (and multistage) air-stripping as a cost-effective alternative for removing VOCs from surfactant micellar solutions compared to the options of using large air strippers or operating at high A/L ratios.

  13. Release of volatile organic compounds (VOCs from the lung cancer cell line CALU-1 in vitro

    Directory of Open Access Journals (Sweden)

    Schubert Jochen

    2008-11-01

    Full Text Available Abstract Background The aim of this work was to confirm the existence of volatile organic compounds (VOCs specifically released or consumed by lung cancer cells. Methods 50 million cells of the human non-small cell lung cancer (NSCLC cell line CALU-1 were incubated in a sealed fermenter for 4 h or over night (18 hours. Then air samples from the headspace of the culture vessel were collected and preconcentrated by adsorption on solid sorbents with subsequent thermodesorption and analysis by means of gas chromatography mass spectrometry (GC-MS. Identification of altogether 60 compounds in GCMS measurement was done not only by spectral library match, but also by determination of retention times established with calibration mixtures of the respective pure compounds. Results The results showed a significant increase in the concentrations of 2,3,3-trimethylpentane, 2,3,5-trimethylhexane, 2,4-dimethylheptane and 4-methyloctane in the headspace of CALU-1 cell culture as compared to medium controls after 18 h. Decreased concentrations after 18 h of incubation were found for acetaldehyde, 3-methylbutanal, butyl acetate, acetonitrile, acrolein, methacrolein, 2-methylpropanal, 2-butanone, 2-methoxy-2-methylpropane, 2-ethoxy-2-methylpropane, and hexanal. Conclusion Our findings demonstrate that certain volatile compounds can be cancer-cell derived and thus indicative of the presence of a tumor, whereas other compounds are not released but seem to be consumed by CALU-1 cells.

  14. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion.

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2014-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not widely used due to the perceived effort in setting them up. In this manuscript, we present a new closed-form analytical expression describing subsurface contaminant vapor concentrations, including subslab vapor concentrations. The expression was derived using Schwarz-Christoffel mapping. Results from this analytical model match well the numerical modeling results. This manuscript also explores the relationship between subslab and exterior soil gas vapor concentrations, and offers insights on what parameters need to receive greater focus in field studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. A Compendium of Volatile Organic Compounds (VOCs) Released By Human Cell Lines.

    Science.gov (United States)

    Filipiak, Wojciech; Mochalski, Pawel; Filipiak, Anna; Ager, Clemens; Cumeras, Raquel; Davis, Cristina E; Agapiou, Agapios; Unterkofler, Karl; Troppmair, Jakob

    2016-01-01

    Volatile organic compounds (VOCs) offer unique insights into ongoing biochemical processes in healthy and diseased humans. Yet, their diagnostic use is hampered by the limited understanding of their biochemical or cellular origin and their frequently unclear link to the underlying diseases. Major advancements are expected from the analyses of human primary cells, cell lines and cultures of microorganisms. In this review, a database of 125 reliably identified VOCs previously reported for human healthy and diseased cells was assembled and their potential origin is discussed. The majority of them have also been observed in studies with other human matrices (breath, urine, saliva, feces, blood, skin emanations). Moreover, continuing improvements of qualitative and quantitative analyses, based on the recommendations of the ISO-11843 guidelines, are suggested for the necessary standardization of analytical procedures and better comparability of results. The data provided contribute to arriving at a more complete human volatilome and suggest potential volatile biomarkers for future validation. Dedication:This review is dedicated to the memory of Prof. Dr. Anton Amann, who sadly passed away on January 6, 2015. He was motivator and motor for the field of breath research.

  16. Screening of Natural Organic Volatiles from Prunus mahaleb L. Honey: Coumarin and Vomifoliol as Nonspecific Biomarkers

    Directory of Open Access Journals (Sweden)

    Mladenka Malenica Staver

    2011-03-01

    Full Text Available Headspace solid-phase microextraction (HS-SPME; PDMS/DVB fibre and ultrasonic solvent extraction (USE; solvent A: pentane and diethyl ether (1:2 v/v, solvent B: dichloromethane followed by gas chromatography and mass spectrometry (GC, GC-MS were used for the analysis of Prunus mahaleb L. honey samples. Screening was focused toward chemical composition of natural organic volatiles to determine if it is useful as a method of determining honey-sourcing. A total of 34 compounds were identified in the headspace and 49 in the extracts that included terpenes, norisoprenoids and benzene derivatives, followed by minor percentages of aliphatic compounds and furan derivatives. High vomifoliol percentages (10.7%–24.2% in both extracts (dominant in solvent B and coumarin (0.3%–2.4% from the extracts (more abundant in solvent A and headspace (0.9%–1.8% were considered characteristic for P. mahaleb honey and highlighted as potential nonspecific biomarkers of the honey’s botanical origin. In addition, comparison with P. mahaleb flowers, leaves, bark and wood volatiles from our previous research revealed common compounds among norisoprenoids and benzene derivatives.

  17. Screening of natural organic volatiles from Prunus mahaleb L. honey: coumarin and vomifoliol as nonspecific biomarkers.

    Science.gov (United States)

    Jerković, Igor; Marijanović, Zvonimir; Staver, Mladenka Malenica

    2011-03-16

    Headspace solid-phase microextraction (HS-SPME; PDMS/DVB fibre) and ultrasonic solvent extraction (USE; solvent A: pentane and diethyl ether (1:2 v/v), solvent B: dichloromethane) followed by gas chromatography and mass spectrometry (GC, GC-MS) were used for the analysis of Prunus mahaleb L. honey samples. Screening was focused toward chemical composition of natural organic volatiles to determine if it is useful as a method of determining honey-sourcing. A total of 34 compounds were identified in the headspace and 49 in the extracts that included terpenes, norisoprenoids and benzene derivatives, followed by minor percentages of aliphatic compounds and furan derivatives. High vomifoliol percentages (10.7%-24.2%) in both extracts (dominant in solvent B) and coumarin (0.3%-2.4%) from the extracts (more abundant in solvent A) and headspace (0.9%-1.8%) were considered characteristic for P. mahaleb honey and highlighted as potential nonspecific biomarkers of the honey's botanical origin. In addition, comparison with P. mahaleb flowers, leaves, bark and wood volatiles from our previous research revealed common compounds among norisoprenoids and benzene derivatives.

  18. In-tube extraction for enrichment of volatile organic hydrocarbons from aqueous samples.

    Science.gov (United States)

    Jochmann, Maik A; Yuan, Xue; Schilling, Beat; Schmidt, Torsten C

    2008-02-01

    In-tube extraction (ITEX) is a novel solventless extraction technique in which a headspace syringe with a needle body filled with a sorbent (here: Tenax TA) is used. The analytes are extracted from sample headspace by dynamic extraction. The needle body is surrounded by a separate heater, which is used for thermal desorption of analytes into the injection port of a GC system. We report here for the first time the optimization and evaluation of a fully automated analytical method based on ITEX. As target analytes, 19 common groundwater contaminants such as halogenated volatiles and monoaromatic compounds have been chosen. Method related parameters such as extraction temperature, number of extraction cycles, extraction and desorption volume as well as extraction and desorption flow rates were investigated in detail. The linear dynamic range of the ITEX method ranged over six orders of magnitude between 0.028 microg/L and 1218 microg/L with linear correlation coefficients between 0.990 and 0.998 for the investigated compounds. Method detection limits for monoaromatic compounds were between 28 ng/L (ethylbenzene) and 68 ng/L (1,2,4-trimethylbenzene). For halogenated volatile organic compounds, method detection limits between 48 ng/L (chloroform) and 799 ng/L (dichloromethane) were obtained. The precision of the method with external calibration was between 3.1% (chloroform ethylbenzene) and 7.4% (1,2,3-trimethylbenzene).

  19. Volatile Organic Compound Emissions from Larrea tridentate (Creosote bush) during the North American Monsoon

    Science.gov (United States)

    Jardine, K. J.; Kurc, S. A.; Guenther, A. B.; Scott, R. L.; Huxman, T. E.; Abrell, L.

    2009-12-01

    The North American monsoon is experienced as a pronounced increase in rainfall from an extremely dry June ( 80 mm) over large areas of the Sonoran desert in southwestern United States and northwestern Mexico. While the sudden availability of water, high temperatures and solar insolation is known to stimulate the primary productivity of the Sonoran desert, little is known about the emissions of volatile organic compounds (VOCs) from this region. Atmospheric VOCs impact climate and air quality by influencing the oxidizing capacity and acidity of the atmosphere and by contributing to aerosol particles. Although it is often a dominant species in North and South American deserts and is known for the production of a rich set of VOCs, few measurements of VOC emissions from creosote bush exist. We present preliminary results from a field study in southern Arizona aimed at quantifying the exchange rates of VOCs from a creosote bush dominated ecosystem during and after the monsoon season. Ecosystem exchange rates were measured with the technique of virtual disjunct eddy covariance (PTR-MS) and relaxed eddy accumulation (GC-MS). Branch enclosure studies show a diurnal pattern of VOCs emissions typically observed in other forest sites including oxygenated VOCs and volatile isoprenoids. However, a large number of additional VOCs mainly derived from the oxidation of fatty acids and the Shikimic Acid Pathway are also released.

  20. Semi-volatile organic compounds as molecular markers for atmospheric and ecosystem transport

    Science.gov (United States)

    Genualdi, Susan

    The use of semi-volatile organic compounds (SOCs) as molecular markers to identify the contributions of regional and long-range atmospheric transport, as well as current and historic sources, and contaminant deposition in remote ecosystems of the Western U.S. was investigated. Trans-Pacific air masses influenced by Siberian biomass burning events had elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and the historic use pesticides dieldrin and alpha-HCH, while air masses influenced by regional fires in the Pacific Northwestern U.S. had enhanced concentrations of PAHs and the current-use pesticides dacthal and endosulfan. This suggests that previously deposited SOCs, such as pesticides, revolatilize to the atmosphere during forest fires. In addition, forest soils collected from a burned area in the Pacific Northwestern U.S. had significantly lower SOC concentrations (34 to 100 %) than soils collected from an unburned area separated only by a two lane road. This confirms that SOCs re-volatilize and/or degrade from soils and vegetation during the burning process. The chiral signatures of alpha-HCH in air masses at three sites in the Pacific Northwestern U.S. indicated that the boundary layer has a non-racemic alpha-HCH signature likely due to re-volatilization of alpha-HCH from the Pacific Ocean and that the free troposphere is a source of racemic alpha-HCH. Racemic alpha-HCH was also associated with Asian and trans-Pacific air masses. Racemic cis and trans-chlordane in Pacific Northwestern U.S. air masses indicated that U.S. urban areas continue to be a source of chlordane to the atmosphere. The deposition of non-racemic alpha-HCH in seasonal snowpack in continental Western U.S. national park high elevation ecosystems reflected regional transport, while the high latitude, Alaskan national parks were influenced by long-range atmospheric transport of racemic alpha-HCH. The chiral signature of alpha-HCH in fish collected from high elevation and high

  1. Direct visualization of polarization reversal of organic ferroelectric memory transistor by using charge modulated reflectance imaging

    Science.gov (United States)

    Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2017-11-01

    By using the charge modulated reflectance (CMR) imaging technique, charge distribution in the pentacene organic field-effect transistor (OFET) with a ferroelectric gate insulator [P(VDF-TrFE)] was investigated in terms of polarization reversal of the P(VDF-TrFE) layer. We studied the polarization reversal process and the carrier spreading process in the OFET channel. The I-V measurement showed a hysteresis behavior caused by the spontaneous polarization of P(VDF-TrFE), but the hysteresis I-V curve changes depending on the applied drain bias, possibly due to the gradual shift of the polarization reversal position in the OFET channel. CMR imaging visualized the gradual shift of the polarization reversal position and showed that the electrostatic field formed by the polarization of P(VDF-TrFE) contributes to hole and electron injection into the pentacene layer and the carrier distribution is significantly dependent on the direction of the polarization. The polarization reversal position in the channel region is governed by the electrostatic potential, and it happens where the potential reaches the coercive voltage of P(VDF-TrFE). The transmission line model developed on the basis of the Maxwell-Wagner effect element analysis well accounts for this polarization reversal process in the OFET channel.

  2. Five Years of Analyses of Volatiles, Isotopes and Organics in Gale Crater Materials

    Science.gov (United States)

    McAdam, A.; Mahaffy, P. R.; Andrejkovicova, S. C.; Archer, P. D., Jr.; Atreya, S. K.; Buch, A.; Coll, P. J.; Conrad, P. G.; Eigenbrode, J. L.; Farley, K. A.; Flesch, G.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Hogancamp, J. V.; House, C. H.; Knudson, C. A.; Lewis, J. M.; Malespin, C.; Martin, P. M.; Millan, M.; Ming, D. W.; Morris, R. V.; Navarro-Gonzalez, R.; Steele, A.; Stern, J. C.; Summons, R. E.; Sutter, B.; Szopa, C.; Teinturier, S.; Trainer, M. G.; Webster, C. R.; Wong, G. M.

    2017-12-01

    Over the last five years, the Curiosity rover has explored a variety of fluvial, lacustrine and aeolian sedimentary rocks, and soils. The Sample Analysis at Mars (SAM) instrument has analysed 3 soil and 12 rock samples, which exhibit significant chemical and mineralogical diversity in over 200 meters of vertical section. Here we will highlight several key insights enabled by recent measurements of the chemical and isotopic composition of inorganic volatiles and organic compounds detected in Gale Crater materials. Until recently samples have evolved O2 during SAM evolved gas analyses (EGA), attributed to the thermal decomposition of oxychlorine phases. A lack of O2 evolution from recent mudstone samples may indicate a difference in the composition of depositional or diagenetic fluids, and can also have implications for the detection of organic compounds since O2 can combust organics to CO2 in the SAM ovens. Recent mudstone samples have also shown little or no evolution of NO attributable to nitrate salts, possibly also as a result of changes in the chemical composition of fluids [1]. Measurements of the isotopic composition of sulfur, hydrogen, nitrogen, chlorine, and carbon in methane evolved during SAM pyrolysis are providing constraints on the conditions of possible paleoenvironments [e.g., 2, 3]. There is evidence of organic C from both EGA and GCMS measurements of Gale samples [e.g., 4, 5]. Organic sulfur volatiles have been detected in several samples, and the first opportunistic derivatization experiment produced a rich dataset indicating the presence of several organic compounds [6, 7]. A K-Ar age has been obtained from the Mojave mudstone, and the age of secondary materials formed by aqueous alteration is likely <3 Ga [8]. This relatively young formation age suggests fluid interactions after the end of most fluvial activity on the surface of Mars. As these highlights show, SAM measurements of solid samples have made diverse and important contributions to

  3. Decomposition of Volatile Organic Compounds and Environmental Hazardous Substances in Water using Discharge Plasma

    Science.gov (United States)

    Satoh, Kohki

    Recent works for the decomposition of gaseous volatile organic compounds (VOCs) and environmental hazardous substances in water using discharge plasma are encapsulated. The kinds of reactors used for the decomposition of VOCs, the decomposition characteristics of VOCs by the reactors and the effects of the discharge type, applied voltage, etc. on VOCs decomposition are briefly described. Further, the detailed investigation of by-products from benzene, toluene and xylene and the estimation of decomposition path of acetone by discharge plasma treatment are introduced as works which contribute to the design of VOC-decomposition reactors and to assuring the safety of VOCs decomposition by the discharge plasma. For the decomposition of environmental hazardous substances in water by discharge plasma, the treatment of aqueous phenol solution and organic dyes are focused. The effects of sparging gas, the conductivity of the solution, background-gas composition, etc. on phenol decomposition rate are described, and the mechanism that the species contributing phenol decomposition change with the background-gas composition is illustrated in detail. Recent works to clarify the by-products of phenol are also introduced. For the decomposition rate of organic dyes, the effects of pH of solution, background-gas composition, etc. on the decomposition rate and the species contributing the decomposition are shown. Further, the efficiency difference for organic-dye decomposition due to the kinds of discharge plasma reactor is introduced.

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

    Science.gov (United States)

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

    2017-04-01

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

  5. Origins of volatile organic compounds emerging from tank 241-C-106 during sluicing

    Energy Technology Data Exchange (ETDEWEB)

    STAUFFER, L.A.

    1999-06-02

    Unexpectedly high concentrations of inorganic gases and volatile organic compounds (VOC) were released from the ventilation stack of tank 241-C-106 during sluicing operations on November 18, 1998. Workers experienced serious discomfort. They reported an obnoxious acrid odor and the 450 ppm VOC in ventilation stack 296-C-006 exceeded the level approved in the air discharge permit. Consequently, the operation was terminated. Subsequent analyses of samples collected opportunistically from the stack indicated many organic compounds including heptenes, heptanones, and normal paraffin hydrocarbons (NPH) and their remnants were present. Subsequently, a process test designed to avoid unnecessary worker exposure and enable collection of analytical samples from the stack, the breathing area, and the receiver tank was conducted on December 16, 1998. The samples obtained during that operation, in which the maximum VOC content of the stack was approximately 35 ppm, have been analyzed by teams at Pacific Northwest National Laboratory and Special Analytic Services (SAS). This report examines the results of these investigations. Future revisions of the report will examine the analytical results obtained for samples collected during sluicing operations in March. This report contains the available evidence about the source term for these emissions. Chapter 2 covers characterization work, including historical information about the layers of waste in the tank, the location of organic compounds in these layers, the total organic carbon (TOC) content and the speciation of organic compounds. Chapter 3 covers the data for the samples from the ventilation stack, which has the highest concentrations of organic compounds. Chapter 4 contains an interpretation of the information connecting the composition of the organic emissions with the composition of the original source term. Chapter 5 summarizes the characterization work, the sample data, and the interpretation of the results.

  6. Organic polar pollutants in surface waters of inland seas.

    Science.gov (United States)

    Orlikowska, Anna; Fisch, Kathrin; Schulz-Bull, Detlef E

    2015-12-30

    Available data about contamination by polar substances are mostly reported for rivers and near-shore waters and only limited studies exists about their occurrence in marine waters. We present concentrations and distribution of several polar pesticides and UV-filters in surface waters of three inland seas, the Baltic, Black and Mediterranean Sea. Many of the investigated compounds were below detection limits, however, those found in off-shore waters raise a concern about their persistence and possible adverse effect on the ecosystem. Despite a longstanding EU-wide ban we were able to detect atrazine in the Mediterranean and the Baltic Sea. Concentrations in the Black Sea were substantially higher. Runoff from agricultural and urban areas was the main transport route to marine ecosystems for investigated compounds, though irgarol in Mediterranean waters was attributed to intense maritime traffic. 2-Phenylbenzimidazole-5-sulfonic acid was the only UV-filter detected in marine waters, while benzophenone-4 was observed in the estuaries. Occurrence of UV-filters was seasonal. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Retardation of volatile organic compounds in ground water in low organic carbon sediments

    International Nuclear Information System (INIS)

    Hoffman, F.

    1995-04-01

    It is postulated that adsorption onto aquifer matrix surfaces is only one of the processes that retard contaminants in ground water in unconsolidated sediments; others include hydrodynamic dispersion, abiotic/biotic degradation, matrix diffusion, partitioning to organic carbon, diffusion into and retention in dead-end pores, etc. This work aims at these processes in defining the K d of VOCs in sediments with low organic carbon content. Experiments performed include an initial column experiment for VOC (TCE and perchloroethylene(PCE)) retardation tests on geological materials, PCE and TCE data from LLNL sediments, and a preliminary multilayer sampler experiment. The VOC K d s in low organic carbon permeable aquifer materials are dependent on the VOC composition and independent of aquifer grain size, indicating that sorption was not operative and that the primary retarding factors are diffusion controlled. The program of future experiments is described

  8. Microporous Polyamide Membranes for Molecular Sieving of Nitrogen from Volatile Organic Compounds.

    Science.gov (United States)

    Zhou, Haoli; Tao, Fei; Liu, Quan; Zong, Chunxin; Yang, Wenchao; Cao, Xingzhong; Jin, Wanqin; Xu, Nanping

    2017-05-15

    Microporous polymer membranes continue to receive tremendous attention for energy-efficient gas separation processes owing to their high separation performances. A new network microporous polyamide membrane with good molecular-sieving performance for the separation of N 2 from a volatile organic compound (VOC) mixture is described. Triple-substituted triptycene was used as the main monomer to form a fisherman's net-shaped polymer, which readily forms a composite membrane by solution casting. This membrane exhibited outstanding separation performance and good stability for the molecular-sieving separation of N 2 over VOCs such as cyclohexane. The rejection rate of the membrane reached 99.2 % with 2098 Barrer N 2 permeability at 24 °C under 4 kPa. This approach promotes development of microporous membranes for separation of condensable gases. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. [Study on monitoring index of individual exposure dose of volatile organic compounds in environment].

    Science.gov (United States)

    Feng, Baohai; Cui, Jiusi; Hao, Shoujin

    2003-11-01

    In order to study the monitoring index of individual exposure dose of volatile organic compounds (VOCs) in environment, the thermal desorption capillary gas chromatographic (TD-GC) analysis was used to examine the VOCs level in air and the expired breath of female workers. Headspace solid phase micro-extraction gas chromatography (SPME-GC) was applied to determine the blood concentration of VOCs in female workers. The results from epidemiological study showed clearly that concentration of 10 subtypes of VOCs in blood, environmental air and expired breath from exposure group were higher than those from control group. The findings from the study suggested that the blood concentration of VOCs was sensitive and specific and this index might be one of good indexes in assessment of individual exposure dose of VOCs.

  10. [Passive personal sampler for exposure to low concentration of volatile organic compounds].

    Science.gov (United States)

    Xu, D; Cui, J; Wang, B

    1999-07-01

    A passive personal sampler has been developed for monitoring volatile organic compounds(VOCs) in ambient air and nonoccupational exposure. The sampler collecting target VOCs is based upon the mechanism of molecular diffusion and absorption onto a single layer of active carbon fibre (ACF) absorbent. After exposure, the ACF is transferred from the sampler into stainless steel tubes for thermal desorption. The desorbed target VOCs is analyzed by capillary GC. Under the condition of facing velocity of 10-260 cm/s, relative humidity of 30%-80%, and temperature of 10-30 C, the sampling rate for benzene, toluene, tetrachloroethylene, p-xylene and styrene is 25.74, 25.16, 25.85, 8.16 and 6.47 ml/min respectively. The analysis on the new passive sampler demonstrated that its relative overall uncertainty for target VOCs was in the range of +/- 25% compared with the active ACF tube sampling method.

  11. Migration of volatile organic contaminations (VOCs) through a deforming clay liner

    Science.gov (United States)

    Zhang, H. J.; Jeng, D.-S.; Barry, D. A.; Seymour, B. R.; Li, L.

    2013-09-01

    A fully coupled thermal-hydraulic-mechanical-chemical (THMC) model was proposed to describe the migration of volatile organic contaminations (VOCs) in unsaturated landfill liners. The vertical soil stress, capillary pressure, air pressure, temperature increase, and solute concentration were selected as the primary variables. Finite deformations were described using Lagrangian coordinates. Non-isothermal moisture transport was found to be dependent on both the temperature gradient and the concentration of the VOCs. The VOCs were assumed to exist and be transported in three phases in the soil: solid, liquid, and gas. An illustrative example of an unsaturated landfill with a compacted clay liner was presented. For the case considered, the transport of gas phase VOCs was found to dominate the migration progress. Moreover, the temperature gradient can accelerate the breakthrough of VOCs in an unsaturated liner, while the mechanical consolidation slowed down the motion of the VOCs.

  12. Volatile organic compounds in indoor air: A review ofconcentrations measured in North America since 1990

    Energy Technology Data Exchange (ETDEWEB)

    ATHodgson@lbl.gov

    2003-04-01

    Central tendency and upper limit concentrations of volatile organic compounds (VOCs) measured in indoor air are summarized and reviewed. Data were obtained from published cross-sectional studies of residential and office buildings conducted in North America from 1990through the present. VOC concentrations in existing residences reported in 12 studies comprise the majority of the data set. Central tendency and maximum concentrations are compared between new and existing residences and between existing residences and office buildings. Historical changes in indoor VOC concentrations since the Clean Air Act Amendments of 1990 are explored by comparing the current data set with two published reviews of previous data obtained primarily in the 1980s. These historical comparisons suggest average indoor concentrations of some toxic air contaminants, such as 1,1,1-trichloroethane have decreased.

  13. Rapid determination of volatile organic compounds in environmentally hazardous wastewaters using solid phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    James, K.J.; Stack, M.A. [Ecotoxicology Research Unit, Chemistry Department, Cork RTC, Bishopstown, Cork (Ireland)

    1997-08-01

    Solid phase micro-extraction (SPME) was applied to the determination of volatile organic compounds (VOC) in wastewater discharges. Environmentally significant samples, typical of those subject to regulatory control, were examined and included discharges from pharmaceutical, petrochemical and municipal sewerage treatment plants. Analysis was performed using gas chromatography - mass spectrometry (GC-MS) following sampling using headspace or immersion SPME. Fused silica fibres, coated with either poly(dimethylsiloxane) or poly(acrylate), were examined to determine VOC which included chloroform, saturated carboxylic acids, alkylbenzenes, phenol, benzonitrile and benzofuran. Detection limits varied from 10 to 170 ng/ml and satisfactory relative standard deviations (%RSD < 10) were obtained. For most samples, headspace sampling was preferred to immersion. SPME was found to be a useful technique for the rapid screening of wastewaters for VOC. (orig.) With 2 figs., 3 tabs.

  14. Emission of volatile organic compounds from medical equipment inside neonatal incubators.

    Science.gov (United States)

    Colareta Ugarte, U; Prazad, P; Puppala, B L; Schweig, L; Donovan, R; Cortes, D R; Gulati, A

    2014-08-01

    To determine emission of volatile organic compounds (VOCs) from plastic medical equipment within an incubator. Air samples from incubators before and after adding medical equipment were analyzed using EPA TO-15 methodology. Headspace analysis was used to identify VOC emissions from each medical equipment item. Air changes per hour (ACH) of each incubator were determined and used to calculate the emission rate of identified VOCs. Cyclohexanone was identified in all incubator air samples. At 28 °C, the mean concentration before and after adding medical equipment items was 2.1 ± 0.6 and 57.2 ± 14.9 μg m(-3),respectively (Pincubator air samples containing plastic medical equipment. The concentration of cyclohexanone within the incubator was inversely related to ACH in the closed mode. The cyclohexanone concentration as well as the emission rate increased with higher temperature.

  15. Quantitative analysis of different volatile organic compounds using an improved electronic nose

    Science.gov (United States)

    Gao, Daqi; Ji, Jiuming; Gong, Jiayu; Cai, Chaoqian

    2012-10-01

    This paper sets up an improved electronic nose with an automatic sampling mode, large volumetric vapors and constant temperature for headspace vapors and gas sensor array. In order to facilitate the fast recovery and good repeatability of gas sensors, the steps taken include (A) short-time contact with odors measured; (B) long-time purification using environmental air; (C) exact calibration using clean air before sampling. We employ multiple single-output perceptrons to discriminate and quantify multiple kinds of odors. This task is first regarded as multiple two-class discrimination problems and then multiple quantification problems, and accomplished by multiple single-output perceptrons followed by multiple single-output perceptrons. The experimental results for measuring and quantifying 12 kinds of volatile organic compounds with changing concentrations show that the type of electronic nose with a hierarchical perceptron model has a simple structure, easy operation, good repeatability and good discrimination and quantification performance.

  16. Quantitative analysis of different volatile organic compounds using an improved electronic nose

    International Nuclear Information System (INIS)

    Gao, Daqi; Ji, Jiuming; Gong, Jiayu; Cai, Chaoqian

    2012-01-01

    This paper sets up an improved electronic nose with an automatic sampling mode, large volumetric vapors and constant temperature for headspace vapors and gas sensor array. In order to facilitate the fast recovery and good repeatability of gas sensors, the steps taken include (A) short-time contact with odors measured; (B) long-time purification using environmental air; (C) exact calibration using clean air before sampling. We employ multiple single-output perceptrons to discriminate and quantify multiple kinds of odors. This task is first regarded as multiple two-class discrimination problems and then multiple quantification problems, and accomplished by multiple single-output perceptrons followed by multiple single-output perceptrons. The experimental results for measuring and quantifying 12 kinds of volatile organic compounds with changing concentrations show that the type of electronic nose with a hierarchical perceptron model has a simple structure, easy operation, good repeatability and good discrimination and quantification performance. (paper)

  17. Utilization of Volatile Organic Compounds as an Alternative for Destructive Abatement

    Directory of Open Access Journals (Sweden)

    Satu Ojala

    2015-07-01

    Full Text Available The treatment of volatile organic compounds (VOC emissions is a necessity of today. The catalytic treatment has already proven to be environmentally and economically sound technology for the total oxidation of the VOCs. However, in certain cases, it may also become economical to utilize these emissions in some profitable way. Currently, the most common way to utilize the VOC emissions is their use in energy production. However, interesting possibilities are arising from the usage of VOCs in hydrogen and syngas production. Production of chemicals from VOC emissions is still mainly at the research stage. However, few commercial examples exist. This review will summarize the commercially existing VOC utilization possibilities, present the utilization applications that are in the research stage and introduce some novel ideas related to the catalytic utilization possibilities of the VOC emissions. In general, there exist a vast number of possibilities for VOC utilization via different catalytic processes, which creates also a good research potential for the future.

  18. Can ornamental potted plants remove volatile organic compounds from indoor air? - a review

    DEFF Research Database (Denmark)

    Dela Cruz, Majbrit; Christensen, Jan H.; Thomsen, Jane Dyrhauge

    2014-01-01

    that plant induced removal of VOCs is a combination of direct (e.g. absorption) and indirect (e.g. biotransformation by microorganisms) mechanisms. They also demonstrate that plants' rate of reducing the level of VOCs is influenced by a number of factors such as plant species, light intensity and VOC......Volatile organic compounds (VOCs) are found in indoor air, and many of these can affect human health (e.g. formaldehyde and benzene are carcinogenic). Plants affect the levels of VOCs in indoor environments, thus they represent a potential green solution for improving indoor air quality...... that at the same time can improve human health. This article reviews scientific studies of plants' ability to remove VOCs from indoor air. The focus of the review is on pathways of VOC removal by the plants and factors affecting the efficiency and rate of VOC removal by plants. Laboratory based studies indicate...

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  20. Photochemical ozone creation potentials for volatile organic compounds: Rationalization and estimation

    Science.gov (United States)

    Jenkin, M. E.; Derwent, R. G.; Wallington, T. J.

    2017-08-01

    The Photochemical Ozone Creation Potential (POCP) scale quantifies the relative abilities of volatile organic compounds (VOCs) to produce ground level ozone. POCP values are usually calculated using atmospheric boundary layer models containing detailed representations of atmospheric VOC degradation chemistry. The sensitivity of POCP values to variation of a number of kinetic and mechanistic parameters has been investigated here. It is shown that POCP values for VOCs can be rationalized in terms of their molecular structure and OH reactivity. As a result, a simple method has been developed and optimized that allows POCP values for north-west European and USA urban reference conditions to be estimated for alkanes, alkenes, aromatic hydrocarbons, and several oxygenated VOC classes without the requirement to construct a detailed chemical mechanism or run an atmospheric model. The procedure for determining the estimated POCP value (POCPE) is described, and the results are presented and discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-07-01

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

  2. Volatile Organic Compounds in Anatomical Pathology Wards: Comparative and Qualitative Assessment of Indoor Airborne Pollution.

    Science.gov (United States)

    Cipolla, Massimo; Izzotti, Alberto; Ansaldi, Filippo; Durando, Paolo; Piccardo, Maria Teresa

    2017-06-07

    The impact of volatile organic compounds (VOCs) on indoor air quality and on human health is widely recognized. However, VOC contamination in hospital indoor air is rarely studied and chemical compounds that singularly do not show high toxicity are not submitted to any regulation. This study aimed to compare VOC contamination in two different anatomical pathology wards in the same hospital. Hydrocarbons, alcohols, and terpenes were sampled by passive diffusive samplers. Analytical tests were performed by thermal desorption coupled with gas chromatography and mass spectrometry detector. Results highlighted a different VOC pollution in the two wards, due to the structural difference of the buildings and different organizational systems. The scarcity of similar data in the literature shows that the presence of VOCs in pathology wards is an underestimated problem. We believe that, because of the adverse effects that VOCs may have on the human health, this topic is worth exploring further.

  3. Hydrogen Safety Project chemical analysis support task: Window ``C`` volatile organic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, B.M.; Stromatt, R.W.; Ross, G.A.; Hoope, E.A.

    1992-01-01

    This data package contains the results obtained by Pacific Northwest Laboratory (PNL) staff in the characterization of samples for the 101-SY Hydrogen Safety Project. The samples were submitted for analysis by Westinghouse Hanford Company (WHC) under the Technical Project Plan (TPP) 17667 and the Quality Assurance Plan MCS-027. They came from a core taken during Window ``C`` after the May 1991 gas release event. The analytical procedures required for analysis were defined in the Test Instructions (TI) prepared by the PNL 101-SY Analytical Chemistry Laboratory (ACL) Project Management Office in accordance with the TPP and the QA Plan. The requested analysis for these samples was volatile organic analysis. The quality control (QC) requirements for each sample are defined in the Test Instructions for each sample. The QC requirements outlined in the procedures and requested in the WHC statement of work were followed.

  4. Hydrogen Safety Project chemical analysis support task: Window C'' volatile organic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, B.M.; Stromatt, R.W.; Ross, G.A.; Hoope, E.A.

    1992-01-01

    This data package contains the results obtained by Pacific Northwest Laboratory (PNL) staff in the characterization of samples for the 101-SY Hydrogen Safety Project. The samples were submitted for analysis by Westinghouse Hanford Company (WHC) under the Technical Project Plan (TPP) 17667 and the Quality Assurance Plan MCS-027. They came from a core taken during Window C'' after the May 1991 gas release event. The analytical procedures required for analysis were defined in the Test Instructions (TI) prepared by the PNL 101-SY Analytical Chemistry Laboratory (ACL) Project Management Office in accordance with the TPP and the QA Plan. The requested analysis for these samples was volatile organic analysis. The quality control (QC) requirements for each sample are defined in the Test Instructions for each sample. The QC requirements outlined in the procedures and requested in the WHC statement of work were followed.

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

    International Nuclear Information System (INIS)

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

    1992-07-01

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

  6. Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

    Directory of Open Access Journals (Sweden)

    M. Mena

    2005-06-01

    Full Text Available Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period. No anthropogenic pollution from Volatile Organic Compounds (VOCs was observed. An overview of the soil radon behaviour as a function of the volcanic activity in the period 1994-2002 is also discussed.

  7. Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming

    DEFF Research Database (Denmark)

    Faubert, Patrick; Tiiva, Paivi; Rinnan, Åsmund

    2010-01-01

    • Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over...... the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. • We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra...... heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. • The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5°C, while litter addition had a minor influence...

  8. Off-season biogenic volatile organic compound emissions from heath mesocosms

    DEFF Research Database (Denmark)

    Rinnan, Riikka; Gierth, Diana; Bilde, Merete

    2013-01-01

    Biogenic volatile organic compounds (BVOCs) affect both atmospheric processes and ecological interactions. Our primary aim was to differentiate between BVOC emissions from above- and belowground plant parts and heath soil outside the growing season. The second aim was to assess emissions from...... herbivory, mimicked by cutting the plants. Mesocosms from a temperate Deschampsia flexuosa-dominated heath ecosystem and a subarctic mixed heath ecosystem were either left intact, the aboveground vegetation was cut, or all plant parts (including roots) were removed. For 3-5 weeks, BVOC emissions were...... measured in growth chambers by an enclosure method using gas chromatography-mass spectrometry. CO2 exchange, soil microbial biomass and soil carbon and nitrogen concentrations were also analyzed. Vegetation cutting increased BVOC emissions by more than 20-fold, and the induced compounds were mainly eight...

  9. Arctic emissions of biogenic volatile organic compounds – from plants, litter and soils

    DEFF Research Database (Denmark)

    Svendsen, Sarah Hagel

    Significant amounts of biogenic volatile organic compounds are emitted from terrestrial ecosystems. These emissions may influence the atmospheric chemistry and the climate. Climate warming will be most pronounced in the Arctic and this will likely have a large effect on the BVOC emissions from...... these areas. Despite this, BVOC emissions from arctic ecosystems are sparsely studied and measurements of high arctic soil and litter BVOC emissions are completely lacking. In this thesis, I have studied BVOC emissions from a high arctic soil moisture gradient, from decomposing shrub litter from high and low...... arctic heaths at increasing temperature and from high arctic active layer soils and permafrost soils during a thaw event and at increasing temperature. Ecosystem BVOC emissions were measured in situ and BVOC emissions from soils and litter were measured from laboratory incubations. BVOCs were sampled...

  10. Process engineering versus product engineering - A case study on volatile organic compounds removal

    DEFF Research Database (Denmark)

    Coutinho, João A.P.; Vilela, T.; Pereira, P.

    2005-01-01

    to the problem-need specified in the beginning of the project, but producing a novel formulation (chemical product design) represents a method that results to a completely xylene-free process which is environmentally and economically more interesting than those generated via the more traditional process......Three solutions for removing the dangerous volatile organic compound (VOC) xylene from an industrial coating process are presented and compared. Two of them are based on classical process engineering principles, i.e., development of separation-cleaning methods such as incineration and adsorption....... The last approach is somewhat different and is based on the so-called product engineering concept, i.e., in this case, a change of the formulation so that xylene is entirely eliminated from the process. It is shown that both the process and the product engineering approaches yield viable solutions...

  11. Electrostatic Selectivity of Volatile Organic Compounds Using Electrostatically Formed Nanowire Sensor.

    Science.gov (United States)

    Mahapatra, Niharendu; Ben-Cohen, Avi; Vaknin, Yonathan; Henning, Alex; Hayon, Joseph; Shimanovich, Klimentiy; Greenspan, Hayit; Rosenwaks, Yossi

    2018-03-23

    For the past several decades, there is growing demand for the development of low-power gas sensing technology for the selective detection of volatile organic compounds (VOCs), important for monitoring safety, pollution, and healthcare. Here we report the selective detection of homologous alcohols and different functional groups containing VOCs using the electrostatically formed nanowire (EFN) sensor without any surface modification of the device. Selectivity toward specific VOC is achieved by training machine-learning based classifiers using the calculated changes in the threshold voltage and the drain-source on current, obtained from systematically controlled biasing of the surrounding gates (junction and back gates) of the field-effect transistors (FET). This work paves the way for a Si complementary metal-oxide-semiconductor (CMOS)-based FET device as an electrostatically selective sensor suitable for mass production and low-power sensing technology.

  12. Exhaled volatile organic compounds for phenotyping chronic obstructive pulmonary disease: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Basanta Maria

    2012-08-01

    Full Text Available Abstract Background Non-invasive phenotyping of chronic respiratory diseases would be highly beneficial in the personalised medicine of the future. Volatile organic compounds can be measured in the exhaled breath and may be produced or altered by disease processes. We investigated whether distinct patterns of these compounds were present in chronic obstructive pulmonary disease (COPD and clinically relevant disease phenotypes. Methods Breath samples from 39 COPD subjects and 32 healthy controls were collected and analysed using gas chromatography time-of-flight mass spectrometry. Subjects with COPD also underwent sputum induction. Discriminatory compounds were identified by univariate logistic regression followed by multivariate analysis: 1. principal component analysis; 2. multivariate logistic regression; 3. receiver operating characteristic (ROC analysis. Results Comparing COPD versus healthy controls, principal component analysis clustered the 20 best-discriminating compounds into four components explaining 71% of the variance. Multivariate logistic regression constructed an optimised model using two components with an accuracy of 69%. The model had 85% sensitivity, 50% specificity and ROC area under the curve of 0.74. Analysis of COPD subgroups showed the method could classify COPD subjects with far greater accuracy. Models were constructed which classified subjects with ≥2% sputum eosinophilia with ROC area under the curve of 0.94 and those having frequent exacerbations 0.95. Potential biomarkers correlated to clinical variables were identified in each subgroup. Conclusion The exhaled breath volatile organic compound profile discriminated between COPD and healthy controls and identified clinically relevant COPD subgroups. If these findings are validated in prospective cohorts, they may have diagnostic and management value in this disease.

  13. Evaporation losses and dispersion of volatile organic compounds from tank farms.

    Science.gov (United States)

    Howari, Fares M

    2015-05-01

    The present study is an application of a Gaussian dispersion model to evaluate volatilization losses from tank farms. It reports methodology to estimate evaporation losses of volatile organic compounds (VOCs) from organic liquid in storage tanks. This study used fixed roof and floating roof equations for breathing and working losses. Total loss, the breathing loss, vapor pressure, molecular weight of the product, tank diameter, diurnal temperature, paint factor, tank capacity, and number of turnovers were considered and factored in the calculation. AERMOD and ALOHA softwares were used to simulate the dispersion of VOCs under normal and accidental scenarios. For the modeling purposes, meteorological data such as annual average ambient temperature, annual average atmospheric pressure, daily minimum ambient temperature, daily maximum ambient temperature, solar insulation factor, and average wind speed were included as input in the calculation and modeling activities. The study took place in Sharjah Emirate in United Arab Emirates, which borders Dubai to the south and Ajman to the north, and the three form a conurbation. The reported method was used to estimate evaporation losses for baseline and hypothetical leak scenarios. Results of this research show that liquid storage tanks in the study area emit a low concentration of VOC under the studied and assumed conditions, e.g., new tanks with high performance sealing as well as the noted earlier climatic conditions. The dispersion of those concentrations is controlled by the prevailing wind direction. The predicted VOCs concentrations were within the range of the measured VOCs values in air. The study found that the spatial distributions of the predicted concentration attenuate with time and distance. Under the reported accidental spill scenario, the Gaussian model indicates that the danger area starts within the zone of less than 10 m. The danger area is subjected to flame pockets, and the VOC concentrations in this

  14. Laboratory measurements of emissions of nonmethane volatile organic compounds from biomass burning in Chinese crop residues

    Science.gov (United States)

    Inomata, S.; Tanimoto, H.; PAN, X.; Taketani, F.; Komazaki, Y.; Miyakawa, T.; Kanaya, Y.; Wang, Z.

    2014-12-01

    The emission factors (EFs) of volatile organic compounds (VOCs) from the burning of Chinese crop residue were investigated as a function of modified combustion efficiency by the laboratory experiments. The VOCs including acetonitrile, aldehydes/ketones, furan, and aromatic hydrocarbons were monitored by proton-transfer-reaction mass spectrometry. Two samples, wheat straw and rape plant, were burned in dry conditions and for some experiments wheat straw was burned under wet conditions. We compared the present data to the field data reported by Kudo et al. [2014]. The agreement between the field and laboratory data was obtained for aromatics for relatively more smoldering data of dry samples but the field data were slightly underestimated compared with the laboratory data for oxygenated VOCs (OVOCs) and acetonitrile. When the EFs from the burning of wet samples were investigated, the underestimations for OVOCs and acetonitrile were improved compared with the data of dry samples. It may be a property of the burning of crop residue in the region of high temperature and high humidity that some inside parts of piled crop residue and/or the crop residue facing on the ground are still wet. But the ratios for acetic acid/glycolaldehyde was still lower than 1. This may suggest that strong loss processes of acetic acid/glycolaldehyde are present in the fresh plume.Kudo S., H. Tanimoto, S. Inomata, S. Saito, X. L. Pan, Y. Kanaya, F. Taketani, Z. F. Wang, H. Chen, H. Dong, M. Zhang, and K. Yamaji (2014), Emissions of nonmethane volatile organic compounds from open crop residue burning in Yangtze River Delta region, China, J. Geophys. Res. Atmos., 119, 7684-7698, doi: 10.1002/2013JD021044.

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

    Science.gov (United States)

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

    2003-09-02

    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.

  16. Hexamethyldisiloxane thin films as sensitive coating for quartz crystal microbalance based volatile organic compounds sensors

    International Nuclear Information System (INIS)

    Boutamine, M.; Bellel, A.; Sahli, S.; Segui, Y.; Raynaud, P.

    2014-01-01

    Hexamethyldisiloxane (HMDSO) thin films coated quartz crystal microbalance (QCM) electrodes have been characterized for the detection of volatile organic compounds (VOCs). The sensitive coatings were plasma polymerized in pure vapor of HMDSO and HMDSO/O 2 mixture. The sensor sensitivity was evaluated by monitoring the frequency shift (∆f) of the coated QCM electrode exposed to different concentrations of VOC vapors, such as ethanol, methanol, benzene and chloroform. The isotherm response characteristics showed good reproducibility and reversibility. For all types of analyte, ∆f were found to be linearly correlated with the concentration of VOC vapor. It was shown that it is possible to tune the chemical affinity of the sensor by changing the oxygen ratio in the deposition gas mixture. Contact angle measurements (CA), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to study surface wettability, chemical composition and surface morphology of the coated QCM electrodes. ATR-FTIR analysis showed the presence of methyl groups around 840 cm −1 due to Si-(CH 3 ) 3 rocking vibration making the elaborated sensor surface hydrophobic. When the coating is performed in HMDSO/O 2 mixture, AFM and SEM images showed an increase in the effective specific surface area of the sensor due to the increase in surface roughness. Surface morphology combined with chemical composition significantly affects the sensitivity of the QCM-based sensor. - Highlights: • Hexamethyldisiloxane layers were evaluated for volatile organic compounds detection. • The kinetic response of the sensor showed good reproducibility and reversibility. • Hydrophobic coating and high specific surface area increase the sensor sensitivity. • Sensor affinity can be controlled by controlling oxygen proportion in the mixture

  17. Hexamethyldisiloxane thin films as sensitive coating for quartz crystal microbalance based volatile organic compounds sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boutamine, M. [Laboratoire des Etudes de Matériaux d' Electronique pour Applications Médicales (LEMEAMED), Faculté des Sciences de la Technologie, Université Constantine 1, Constantine 25000 (Algeria); Bellel, A., E-mail: azzedine.bellel@gmail.com [Laboratoire des Etudes de Matériaux d' Electronique pour Applications Médicales (LEMEAMED), Faculté des Sciences de la Technologie, Université Constantine 1, Constantine 25000 (Algeria); Sahli, S. [Laboratoire de Microsystèmes et Instrumentation (LMI), Faculté des Sciences de la Technologie, Université Constantine 1, Constantine 25000 (Algeria); Segui, Y.; Raynaud, P. [Laboratoire Plasma et Conversion de l' Energie (LAPLACE), Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex (France)

    2014-02-03

    Hexamethyldisiloxane (HMDSO) thin films coated quartz crystal microbalance (QCM) electrodes have been characterized for the detection of volatile organic compounds (VOCs). The sensitive coatings were plasma polymerized in pure vapor of HMDSO and HMDSO/O{sub 2} mixture. The sensor sensitivity was evaluated by monitoring the frequency shift (∆f) of the coated QCM electrode exposed to different concentrations of VOC vapors, such as ethanol, methanol, benzene and chloroform. The isotherm response characteristics showed good reproducibility and reversibility. For all types of analyte, ∆f were found to be linearly correlated with the concentration of VOC vapor. It was shown that it is possible to tune the chemical affinity of the sensor by changing the oxygen ratio in the deposition gas mixture. Contact angle measurements (CA), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to study surface wettability, chemical composition and surface morphology of the coated QCM electrodes. ATR-FTIR analysis showed the presence of methyl groups around 840 cm{sup −1} due to Si-(CH{sub 3}){sub 3} rocking vibration making the elaborated sensor surface hydrophobic. When the coating is performed in HMDSO/O{sub 2} mixture, AFM and SEM images showed an increase in the effective specific surface area of the sensor due to the increase in surface roughness. Surface morphology combined with chemical composition significantly affects the sensitivity of the QCM-based sensor. - Highlights: • Hexamethyldisiloxane layers were evaluated for volatile organic compounds detection. • The kinetic response of the sensor showed good reproducibility and reversibility. • Hydrophobic coating and high specific surface area increase the sensor sensitivity. • Sensor affinity can be controlled by controlling oxygen proportion in the mixture.

  18. Fluxes of biogenic volatile organic compounds measured and modelled above a Norway spruce forest

    Science.gov (United States)

    Juráň, Stanislav; Fares, Silvano; Pallozzi, Emanuele; Guidolotti, Gabriele; Savi, Flavia; Alivernini, Alessandro; Calfapietra, Carlo; Večeřová, Kristýna; Křůmal, Kamil; Večeřa, Zbyněk; Cudlín, Pavel; Urban, Otmar

    2016-04-01

    Fluxes of biogenic volatile organic compounds (BVOCs) were investigated at Norway spruce forest at Bílý Kříž in Beskydy Mountains of the Czech Republic during the summer 2014. A proton-transfer-reaction-time-of-flight mass spectrometer (PTR-TOF-MS, Ionicon Analytik, Austria) has been coupled with eddy-covariance system. Additionally, Inverse Lagrangian Transport Model has been used to derive fluxes from concentration gradient of various monoterpenes previously absorbed into n-heptane by wet effluent diffusion denuder with consequent quantification by gas chromatography with mass spectrometry detection. Modelled data cover each one day of three years with different climatic conditions and previous precipitation patterns. Model MEGAN was run to cover all dataset with monoterpene fluxes and measured basal emission factor. Highest fluxes measured by eddy-covariance were recorded during the noon hours, represented particularly by monoterpenes and isoprene. Inverse Lagrangian Transport Model suggests most abundant monoterpene fluxes being α- and β-pinene. Principal component analysis revealed dependencies of individual monoterpene fluxes on air temperature and particularly global radiation; however, these dependencies were monoterpene specific. Relationships of monoterpene fluxes with CO2 flux and relative air humidity were found to be negative. MEGAN model correlated to eddy-covariance PTR-TOF-MS measurement evince particular differences, which will be shown and discussed. Bi-directional fluxes of oxygenated short-chain volatiles (methanol, formaldehyde, acetone, acetaldehyde, formic acid, acetic acid, methyl vinyl ketone, methacrolein, and methyl ethyl ketone) were recorded by PTR-TOF-MS. Volatiles of anthropogenic origin as benzene and toluene were likely transported from the most benzene polluted region in Europe - Ostrava city and adjacent part of Poland around Katowice, where metallurgical and coal mining industries are located. Those were accumulated during

  19. Kinetics of volatile organic compound sorption/desorption on clay minerals

    Science.gov (United States)

    Morrissey, Fergus A.; Grismer, Mark E.

    1999-03-01

    Soils surrounding industrial sites or at locales where industrial chemicals are utilized, frequently become contaminated through unsuitable discharge of potentially hazardous organic compounds. The fate and transport of these chemicals must be sufficiently understood to predict detrimental environmental impacts and to develop technically and economically appropriate remedial action to minimize environmental degradation. Improving our understanding of the processes involved in organic pollutant vapor transport is important because the gas phase is often the most mobile, and therefore most potentially hazardous phase. In order to gain a better understanding of the basic kinetic processes affecting soil adsorption/desorption of volatile organic compounds (VOC's) in the vapor phase, we conducted VOC adsorption/desorption experiments using oven-dry clay minerals. Transient, isothermal, gravimetric sorption experiments using volatile organic compounds (VOC's) acetone, benzene and toluene onto pure clay minerals obtained from Ward's Scientific (kaolinite, illite, and Ca-montmorillonite) suggest a biphasic sorption mechanism on these minerals. Experimental results indicate that hydrophobic sorption onto oven-dry clay minerals with negligible soil organic matter is controlled by rates of inter-particle Fickian diffusion mechanisms, intra-particle Fickian diffusion mechanisms, and sorption kinetics. Using an analytical solution to Fick's Second Law where sorption is partitioned into macroscopic and microscopic domains, each with unique diffusion time constants, enables precise prediction of experimental sorption observations. Correlation coefficients of 0.999 were found between the parameter optimized analytical solution and very large sets of experimental data. Macroscopic diffusion coefficients ranged from 10 -2 to 10 -4 cm 2/min, while microscopic diffusion coefficients ranged from 10 -12 to 10 -17 cm 2/min. Sorption rates suggest that significant fractions of VOC

  20. Molecular Composition and Volatility of Organic Aerosol in the Southeastern U.S.: Implications for IEPOX Derived SOA.

    Science.gov (United States)

    Lopez-Hilfiker, F D; Mohr, C; D'Ambro, E L; Lutz, A; Riedel, T P; Gaston, C J; Iyer, S; Zhang, Z; Gold, A; Surratt, J D; Lee, B H; Kurten, T; Hu, W W; Jimenez, J; Hallquist, M; Thornton, J A

    2016-03-01

    We present measurements as part of the Southern Oxidant and Aerosol Study (SOAS) during which atmospheric aerosol particles were comprehensively characterized. We present results utilizing a Filter Inlet for Gases and AEROsol coupled to a chemical ionization mass spectrometer (CIMS). We focus on the volatility and composition of isoprene derived organic aerosol tracers and of the bulk organic aerosol. By utilizing the online volatility and molecular composition information provided by the FIGAERO-CIMS, we show that the vast majority of commonly reported molecular tracers of isoprene epoxydiol (IEPOX) derived secondary organic aerosol (SOA) is derived from thermal decomposition of accretion products or other low volatility organics having effective saturation vapor concentrations SOA has a higher volatility than the remaining bulk. That IEPOX-SOA, and more generally bulk organic aerosol in the Southeastern U.S. is comprised of effectively nonvolatile material has important implications for modeling SOA derived from isoprene, and for mechanistic interpretations of molecular tracer measurements. Our results show that partitioning theory performs well for 2-methyltetrols, once accretion product decomposition is taken into account. No significant partitioning delays due to aerosol phase or viscosity are observed, and no partitioning to particle-phase water or other unexplained mechanisms are needed to explain our results.

  1. Measurement and estimated health risks of volatile organic compounds and polychlorinated biphenyls in air at the Hanford Site

    International Nuclear Information System (INIS)

    Patton, G.W.; Cooper, A.T.; Blanton, M.L.

    1994-10-01

    A variety of radioactive and nonradioactive chemicals have been released in effluent streams and discharged to waste disposal facilities during the nuclear materials production period at the Hanford Site. Extensive environmental surveillance for radioactive materials has occurred at Hanford; however, only limited information is available on the types and concentrations of organic pollutants potentially present. This report describes work performed to provide the Hanford Site Surface Environmental Surveillance Project with representative air concentration data for volatile organic compounds and polychlorinated biphenyls (PCBs). US Environmental Protection Agency (USEPA) volatile organic compound sampling methods evaluated for Hanford Site use were carbon-based adsorbent traps (TO-2) and Summa air canisters (TO-14). Polychlorinated biphenyls were sampled using USEPA method (TO-4), which uses glass fiber filters and polyurethane foam adsorbent beds to collect the PCBS. This report also presents results for environmental surveillance samples collected for volatile organic compound and PCB analyses from 1990 to 1993. All measured air concentrations of volatile organic compounds and PCBs were well below applicable maximum allowable concentration standards for air contaminants. Because of the lack of ambient air concentration standards, a conservative estimate is provided of the potential human health impacts from exposure to the ambient air concentrations measured on the Hanford Site

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

    Directory of Open Access Journals (Sweden)

    Philippe Moulin

    2011-03-01

    Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  3. The influence of semi-volatile and reactive primary emissions on the abundance and properties of global organic aerosol

    Science.gov (United States)

    Jathar, S. H.; Farina, S. C.; Robinson, A. L.; Adams, P. J.

    2012-04-01

    Semi-volatile and reactive primary organic aerosols are modeled on a global scale using the GISS GCM II' "unified" climate model. We employ the volatility basis set framework to simulate emissions, chemical reactions and phase partitioning of primary and secondary organic aerosol (POA and SOA). The model also incorporates the emissions and reactions of intermediate volatility organic compounds (IVOCs) as a source of organic aerosol (OA), one that has been missing in most prior work. Model predictions are evaluated against a broad set of observational constraints including mass concentrations, degree of oxygenation, volatility and isotopic composition. A traditional model that treats POA as non-volatile and non-reactive is also compared to the same set of observations to highlight the progress made in this effort. The revised model predicts a global dominance of SOA and brings the POA/SOA split into better agreement with ambient measurements. This change is due to traditionally defined POA evaporating and the evaporated vapors oxidizing to form non-traditional SOA. IVOCs (traditionally not included in chemical transport models) oxidize to form condensable products that account for a third of total OA, suggesting that global models have been missing a large source of OA. Predictions of the revised model for the SOA fraction at 17 different locations compared much better to observations than predictions from the traditional model. Model-predicted volatility is compared with thermodenuder data collected at three different field campaigns: FAME-2008, MILAGRO-2006 and SOAR-2005. The revised model predicts the OA volatility much more closely than the traditional model. When compared against monthly averaged OA mass concentrations measured by the IMPROVE network, predictions of both the revised and traditional model lie within a factor of two in summer and mostly within a factor of five during winter. A sensitivity analysis indicates that the winter comparison can be

  4. Quasi-unipolar pentacene films embedded with fullerene for non-volatile organic transistor memories

    International Nuclear Information System (INIS)

    Lee, Juhee; Lee, Sungpyo; Lee, Moo Hyung; Kang, Moon Sung

    2015-01-01

    Quasi-unipolar non-volatile organic transistor memory (NOTM) can combine the best characteristics of conventional unipolar and ambipolar NOTMs and, as a result, exhibit improved device performance. Unipolar NOTMs typically exhibit a large signal ratio between the programmed and erased current signals but also require a large voltage to program and erase the memory cells. Meanwhile, an ambipolar NOTM can be programmed and erased at lower voltages, but the resulting signal ratio is small. By embedding a discontinuous n-type fullerene layer within a p-type pentacene film, quasi-unipolar NOTMs are fabricated, of which the signal storage utilizes both electrons and holes while the electrical signal relies on only hole conduction. These devices exhibit superior memory performance relative to both pristine unipolar pentacene devices and ambipolar fullerene/pentacene bilayer devices. The quasi-unipolar NOTM exhibited a larger signal ratio between the programmed and erased states while also reducing the voltage required to program and erase a memory cell. This simple approach should be readily applicable for various combinations of advanced organic semiconductors that have been recently developed and thereby should make a significant impact on organic memory research

  5. Sniffing on microbes: diverse roles of microbial volatile organic compounds in plant health.

    Science.gov (United States)

    Bitas, Vasileios; Kim, Hye-Seon; Bennett, Joan W; Kang, Seogchan

    2013-08-01

    Secreted proteins and metabolites play diverse and critical roles in organismal and organism-environment interactions. Volatile organic compounds (VOC) can travel far from the point of production through the atmosphere, porous soils, and liquid, making them ideal info-chemicals for mediating both short- and long-distance intercellular and organismal interactions. Critical ecological roles for animal- and plant-derived VOC in directing animal behaviors and for VOC as a language for plant-to-plant communication and regulators of various physiological processes have been well documented. Similarly, microbial VOC appear to be involved in antagonism, mutualism, intra- and interspecies regulation of cellular and developmental processes, and modification of their surrounding environments. However, the available knowledge of how microbial VOC affect other organisms is very limited. Evidence supporting diverse roles of microbial VOC with the focus on their impact on plant health is reviewed here. Given the vast diversity of microbes in nature and the critical importance of microbial communities associated with plants for their ecology and fitness, systematic exploration of microbial VOC and characterization of their biological functions and ecological roles will likely uncover novel mechanisms for controlling diverse biological processes critical to plant health and will also offer tangible practical benefits in addressing agricultural and environmental problems.

  6. Real-time and online screening method for materials emitting volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Changhyuk [University of Minnesota, Department of Mechanical Engineering (United States); Sul, Yong Tae [Hoseo University (Korea, Republic of); Pui, David Y. H., E-mail: dyhpui@umn.edu [University of Minnesota, Department of Mechanical Engineering (United States)

    2016-09-15

    In the semiconductor industry, volatile organic compounds (VOCs) in the cleanroom air work as airborne molecular contamination, which reduce the production yield of semiconductor chips by forming nanoparticles and haze on silicon wafers and photomasks under ultraviolet irradiation during photolithography processes. Even though VOCs in outdoor air are removed by gas filters, VOCs can be emitted from many kinds of materials used in cleanrooms, such as organic solvents and construction materials (e.g., adhesives, flame retardants and sealants), threatening the production of semiconductors. Therefore, finding new replacements that emit lower VOCs is now essential in the semiconductor industry. In this study, we developed a real-time and online method to screen materials for developing the replacements by converting VOCs into nanoparticles under soft X-ray irradiation. This screening method was applied to measure VOCs emitted from different kinds of organic solvents and adhesives. Our results showed good repeatability and high sensitivity for VOCs, which come from aromatic compounds, some alcohols and all tested adhesives (Super glue and cleanroom-use adhesives). In addition, the overall trend of measured VOCs from cleanroom-use adhesives was well matched with those measured by a commercial thermal desorption–gas chromatography–mass spectrometry, which is a widely used off-line method for analyzing VOCs. Based on the results, this screening method can help accelerate the developing process for reducing VOCs in cleanrooms.

  7. Inkjet-printing of non-volatile organic resistive devices and crossbar array structures

    Science.gov (United States)

    Sax, Stefan; Nau, Sebastian; Popovic, Karl; Bluemel, Alexander; Klug, Andreas; List-Kratochvil, Emil J. W.

    2015-09-01

    Due to the increasing demand for storage capacity in various electronic gadgets like mobile phones or tablets, new types of non-volatile memory devices have gained a lot of attention over the last few years. Especially multilevel conductance switching elements based on organic semiconductors are of great interest due to their relatively simple device architecture and their small feature size. Since organic semiconductors combine the electronic properties of inorganic materials with the mechanical characteristics of polymers, this class of materials is suitable for solution based large area device preparation techniques. Consequently, inkjet based deposition techniques are highly capable of facing preparation related challenges. By gradually replacing the evaporated electrodes with inkjet printed silver, the preparation related influence onto device performance parameters such as the ON/OFF ratio was investigated with IV measurements and high resolution transmission electron microscopy. Due to the electrode surface roughness the solvent load during the printing of the top electrode as well as organic layer inhomogeneity's the utilization in array applications is hampered. As a prototypical example a 1diode-1resistor element and a 2×2 subarray from 5×5 array matrix were fully characterized demonstrating the versatility of inkjet printing for device preparation.

  8. Stability of dispersions in polar organic media. I. Electrostatic stabilization

    NARCIS (Netherlands)

    Rooy, N. de; Bruyn, P.L. de; Overbeek, J.Th.G.

    Electrostatically stabilized sols of silver, silver iodide, α-goethite, and copper phthalocyanine in methanol, ethanol, isopropanol, and acetone have been prepared and characterized. Coagulation concentrations with electrolytes of various charge numbers have been determined in water, in organic

  9. Partitioning of polar and non-polar neutral organic chemicals into human and cow milk.

    Science.gov (United States)

    Geisler, Anett; Endo, Satoshi; Goss, Kai-Uwe

    2011-10-01

    The aim of this work was to develop a predictive model for milk/water partition coefficients of neutral organic compounds. Batch experiments were performed for 119 diverse organic chemicals in human milk and raw and processed cow milk at 37°C. No differences (milk were observed. The polyparameter linear free energy relationship model fit the calibration data well (SD=0.22 log units). An experimental validation data set including hormones and hormone active compounds was predicted satisfactorily by the model. An alternative modelling approach based on log K(ow) revealed a poorer performance. The model presented here provides a significant improvement in predicting enrichment of potentially hazardous chemicals in milk. In combination with physiologically based pharmacokinetic modelling this improvement in the estimation of milk/water partitioning coefficients may allow a better risk assessment for a wide range of neutral organic chemicals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Xenoendocrine pollutants may reduce size of sexual organs in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Sonne, Christian; Leifsson, Páll Skuli; Dietz, Rune

    2006-01-01

    Reproductive organs from 55 male and 44 female East Greenland polar bears were examined to investigate the potential negative impact from organohalogen pollutants (OHCs). Multiple regressions normalizing for age showed a significant inverse relationship between OHCs and testis length and baculum.......01) and uterine horn length and HCB (p = 0.02). The study suggests thatthere is an impact from xenoendocrine pollutants on the size of East Greenland polar bear genitalia. This may pose a riskto this polar bear subpopulation in the future because of reduced sperm and egg quality/quantity and uterus and penis size...

  11. Characterization of volatile and polar compounds of Jiaogulan Tea [Gynostemma pentaphyllum (Thunb.) Makino] by hyphenated analytical techniques

    Science.gov (United States)

    Jiaogulan [Gynostemma pentaphyllum (Thunb.) Makino] is a Chinese medical plant from southern Asia that has rapidly gained popularity and interest for its health-promotive and therapeutic properties. The volatile composition of jiaogulan tea was analyzed by using headspace-solid phase microextraction...

  12. Biogenic volatile organic compounds as a potential stimulator for organic contaminant degradation by soil microorganisms

    International Nuclear Information System (INIS)

    McLoughlin, Emma; Rhodes, Angela H.; Owen, Susan M.; Semple, Kirk T.

    2009-01-01

    The effects of monoterpenes on the degradation of 14 C-2,4-dichlorophenol (DCP) were investigated in soils collected from areas surrounding monoterpene and non-monoterpene-emitting vegetation. Indigenous microorganisms degraded 14 C-2,4-DCP to 14 CO 2 , after 1 d contact time. Degradation was enhanced by prior exposure of the soils to 2,4-DCP for 32 d, increasing extents of mineralisation up to 60%. Monoterpene amendments further enhanced 2,4-DCP degradation, but only following pre-exposure to both 2,4-DCP and monoterpene, with total 2,4-DCP mineralisation extents of up to 71%. Degradation was greatest at the higher monoterpene concentrations (≥1 μg kg -1 ). Total mineralisation extents were similar between concentrations, but higher than the control and the 0.1 μg kg -1 amendment, indicating that increases in monoterpene concentration has a diminishing enhancing effect. We suggest that monoterpenes can stimulate the biodegradation of 2,4-DCP by indigenous soil microorganisms and that monoterpene amendment in soils is an effective strategy for removing organic contaminants. - A amendment of soils with monoterpenes may induce organic contaminant degradation by indigenous soil microorganisms

  13. 40 CFR Table 1 to Subpart B of... - Volatile Organic Compound (VOC) Content Limits for Automobile Refinish Coatings

    Science.gov (United States)

    2010-07-01

    ... Limits for Automobile Refinish Coatings 1 Table 1 to Subpart B of Part 59 Protection of Environment... Automobile Refinish Coatings Pt. 59, Subpt. B, Table 1 Table 1 to Subpart B of Part 59—Volatile Organic Compound (VOC) Content Limits for Automobile Refinish Coatings Coating category Grams VOC per liter Pounds...

  14. Sorbent-coated diffusion denuders for direct measurement of gas/particle partitioning by semi-volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gundel, L.A. [Lawrence Berkeley National Lab., CA (United States); Lane, D.A. [Atmospheric Environment Service, North York, Ontario (Canada)

    1998-01-01

    Sorbent-coated annular denuder-based samplers have been developed for direct determination of both gaseous and particulate semi-volatile organic species. The first such sampler, the Integrated Organic Vapor/Particle Sampler, has been validated for sampling semi-volatile PAH in ambient air and environmental tobacco smoke. Multi-channel versions of the IOVPS have been used successfully for investigation of gas/particle partitioning of a variety of semi-volatile organic species in combustion source-enriched environmental chambers. Subsequent improvements have resulted in two new higher-capacity samplers, the IOGAPS and the jumbo-IOGAPS, that use the same sorbent for sampling trace organics in the ambient atmosphere for 24--48 hr periods over a wide temperature range. Construction of these new samplers began by incorporating the IOVPS coating technology onto the gas collection surfaces of the higher capacity GAP sampler. Substantial design effort aims to ensure that vapor phase components as volatile as naphthalene can be trapped efficiently and retained by the sorbent-coated surface while the particles pass through to the filter.

  15. Impact of production location, production system, and variety on the volatile organic compounds fingerprints and sensory characteristics of tomatoes

    NARCIS (Netherlands)

    Muilwijk, Mirthe; Heenan, Samuel; Koot, Alex; Ruth, Van Saskia M.

    2015-01-01

    Consumers have more and more interest in where and how their foods are produced. However, it is often challenging to discriminate products from different production locations and systems. The objective of this study was to examine fingerprinting of volatile organic compounds (VOCs) as an approach

  16. Cereal crop volatile organic compound induction after mechanical injury, beetle herbivory (Oulema spp.), or fungal infection (Fusarium spp.)

    Science.gov (United States)

    Herbivory, mechanical injury or pathogen infestation to vegetative tissues can induce volatile organic compounds (VOCs) production, which can provide defensive functions to injured and uninjured plants. In our studies with ‘McNeal’ wheat, ‘Otana’ oat, and ‘Harrington’ barley, plants that were mechan...

  17. Surface and boundary layer exchanges of volatile organic compounds, nitrogen oxides and ozone during the GABRIEL campaign

    NARCIS (Netherlands)

    Ganzeveld, L.; Eerdekens, G.; Feig, G.; Fischer, H.; Harder, H.; Konigstedt, R.; Kubistin, D.; Martinez, M.; Meixner, F. X.; Scheeren, H. A.; Sinha, V.; Taraborrelli, D.; Williams, J.; de Arellano, J. Vila-Guerau; Lelieveld, J.

    2008-01-01

    We present an evaluation of sources, sinks and turbulent transport of nitrogen oxides, ozone and volatile organic compounds (VOC) in the boundary layer over French Guyana and Suriname during the October 2005 GABRIEL campaign by simulating observations with a single-column chemistry and climate model

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

    Science.gov (United States)

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

  19. VOLATILE ORGANIC COMPOUND EMISSIONS FROM LATEX PAINT-PART 2. TEST HOUSE STUDIES AND INDOOR AIR QUALITY (IAQ) MODELING

    Science.gov (United States)

    Emission models developed using small chamber data were combined with an Indoor Air Quality (IAQ) model to analyze the impact of volatile organic compound (VOC) emissions from latex paint on indoor environments. Test house experiments were conducted to verify the IAQ model's pred...

  20. Proton transfer reaction-mass spectrometry volatile organic compound fingerprinting for monovarietal extra virgin olive oil identification

    NARCIS (Netherlands)

    Ruiz-Samblas, C.; Tres, A.; Koot, A.H.; Ruth, van S.M.; Gonzalez-Casado, A.; Cuadros-Rodriguez, L.

    2012-01-01

    Proton transfer reaction-mass spectrometry (PTR-MS) is a relatively new technique that allows the fast and accurate qualification of the volatile organic compound (VOC) fingerprint. This paper describes the analysis of thirty samples of extra virgin olive oil, of five different varieties of olive

  1. Volatile Organic Compounds (VOCs) in the Ambient Air Of Concentration Unit of Sar-Cheshmeh Copper Complex

    International Nuclear Information System (INIS)

    Faghihi-Zrandi, A.; Akhgar, M. R.

    2016-01-01

    Air pollutants including gases, vapors and particles, are emitted from different sources. Volatile organic compounds are the most important pollutants in the ambient air of industries. The present study was carried out to identify and measurement of volatile organic compounds in concentration unit of Sar-Cheshmeh Copper Complex. In this study, sampling of the volatile organic compounds was done by using activated charcoal tube. To identify and measure these compounds gas chromatography/mass spectroscopy were used. Thirteen volatile organic compounds were identified in the ambient air of concentration unit. Among these compounds, the mean value and maximum concentration of isopropyl alcohol and nonane were 255, 640 μg/m3 and 1577, 14400 μg/m3, respectively. By using SPSS software and independent sample t- test, showed that there were no significant difference between mean value concentration of isopropyl alcohol and nonane in the ambient air and TLV values of these compounds (isopropyl alcohol; 200 ppm and nonane; 200 ppm) (P >0.05).

  2. Emissions control of volatile organic compounds in petroleum industry; Controle de emissoes de compostos organicos volateis na industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Gutierres, Ricardo; Moreira, Andrea Cristina de Castro Araujo [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). P e D de Energia e Desenvolvimento Sustentavel (PDEDS)

    2004-07-01

    Volatile organic compounds are among the most common pollutants emitted by refining processes. The sources of these emissions should be controlled for preserving the ambient air quality. This article outlines the main factors to be considered for defining an effective emissions control strategy and compares the major characteristics of the available control technologies. (author)

  3. Profile of volatile organic compounds in exhaled breath changes as a result of gluten-free diet

    NARCIS (Netherlands)

    Baranska, Agnieszka; Tigchelaar, Ettje; Smolinska, Agnieszka; Dallinga, Jan W.; Moonen, Edwin J. C.; Dekens, Jackie A. M.; Wijmenga, Cisca; Zhernakova, Alexandra; van Schooten, Frederik J.

    In the present longitudinal study, we followed volatile organic compounds (VOCs) excreted in exhaled breath of 20 healthy individuals over time, while adhering to a gluten-free diet for 4 weeks prior to adherence to a normal diet. We used gas chromatography coupled with mass spectrometry

  4. Volatile Organic Compounds Obtained by in Vitro Callus Cultivation of Plectranthus ornatus Codd. (Lamiaceae

    Directory of Open Access Journals (Sweden)

    Fabio S. de Oliveira

    2013-08-01

    Full Text Available 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 (α-terpinyl acetate and the monoterpenes α-thujene, α-pinene, β-pinene, camphene, sabinene and α-limonene that were present in the volatile fractions. Besides α-terpinyl acetate, isobornyl acetate and α-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 α-terpinyl acetate and isocumene were detected and, with 2.26 µM of 2,4-D was produced mainly α-terpinyl acetate, α-thujene and β-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.

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

    Science.gov (United States)

    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

    2013-08-26

    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 (α-terpinyl acetate) and the monoterpenes α-thujene, α-pinene, β-pinene, camphene, sabinene and α-limonene that were present in the volatile fractions. Besides α-terpinyl acetate, isobornyl acetate and α-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 α-terpinyl acetate and isocumene were detected and, with 2.26 µM of 2,4-D was produced mainly α-terpinyl acetate, α-thujene and β-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.

  6. Toxic volatile organic compounds in environmental tobacco smoke: Emission factors for modeling exposures of California populations

    Energy Technology Data Exchange (ETDEWEB)

    Daisey, J.M.; Mahanama, K.R.R.; Hodgson, A.T. [Lawrence Berkeley Lab., CA (United States)

    1994-10-01

    The primary objective of this study was to measure emission factors for selected toxic air contaminants in environmental tobacco smoke (ETS) using a room-sized environmental chamber. The emissions of 23 volatile organic compounds (VOCs), including, 1,3-butadiene, three aldehydes and two vapor-phase N-nitrosamines were determined for six commercial brands of cigarettes and reference cigarette 1R4F. The commercial brands were selected to represent 62.5% of the cigarettes smoked in California. For each brand, three cigarettes were machine smoked in the chamber. The experiments were conducted over four hours to investigate the effects of aging. Emission factors of the target compounds were also determined for sidestream smoke (SS). For almost all target compounds, the ETS emission factors were significantly higher than the corresponding SS values probably due to less favorable combustion conditions and wall losses in the SS apparatus. Where valid comparisons could be made, the ETS emission factors were generally in good agreement with the literature. Therefore, the ETS emission factors, rather than the SS values, are recommended for use in models to estimate population exposures from this source. The variabilities in the emission factors ({mu}g/cigarette) of the selected toxic air contaminants among brands, expressed as coefficients of variation, were 16 to 29%. Therefore, emissions among brands were Generally similar. Differences among brands were related to the smoked lengths of the cigarettes and the masses of consumed tobacco. Mentholation and whether a cigarette was classified as light or regular did not significantly affect emissions. Aging was determined not to be a significant factor for the target compounds. There were, however, deposition losses of the less volatile compounds to chamber surfaces.

  7. Turbulent exchange and segregation of HOx radicals and volatile organic compounds above a deciduous forest

    Directory of Open Access Journals (Sweden)

    G. Kramm

    2010-07-01

    Full Text Available The eddy covariance method was applied for the first time to estimate fluxes of OH and HO2 together with fluxes of isoprene, the sum of methyl vinyl ketone (MVK and methacrolein (MACR and the sum of monoterpenes above a mixed deciduous forest. Highly sensitive measurements of OH and HO2 were performed by laser induced fluorescence (LIF, and biogenic volatile organic compounds (BVOCs were measured by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS at a time resolution of 5 s, each. Wind speed was measured by a sonic anemometer at 10 Hz. The one-day feasibility study was conducted at a total height of 37 m, about 7 m above forest canopy, during the ECHO (Emission and CHemical transformation of biogenic volatile Organic compounds intensive field study in July 2003. The daytime measurements yielded statistically significant OH fluxes directed downward into the direction of the canopy and HO2 fluxes mainly upward out of the canopy. This hints towards a significant local chemical sink of OH by reactions with BVOCs, other organic and inorganic compounds and conversion of OH to HO2 above the canopy. For OH the measured flux is locally balanced by chemical sources and sinks and direct transport of OH plays no important role for the local chemical OH budget at the measurement height, as expected from the short OH lifetime (2 the chemical lifetime (20 s is in the range of the turbulent transport time for transfer between the top of the canopy and the measuring point. In this case, the radical balance is significantly influenced by both chemistry and transport processes. In addition, the highly time-resolved trace gas measurements were used to calculate the intensity of segregation of OH and BVOCs, demonstrating that the effective reaction rate of isoprene and OH was slowed down as much as 15% due to inhomogeneous mixing of the reactants. The paper describes the results, the applied methods and provides a detailed analysis of possible systematic errors

  8. The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space

    Science.gov (United States)

    Large-scale assemblies of people in a con'ned space can exert signi'cant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying 'ngerprint volatile organic compounds (VOCs) such as acetone, toluene, ...

  9. Analytical modelling of stable isotope fractionation of volatile organic compounds in the unsaturated zone

    Science.gov (United States)

    Bouchard, Daniel; Cornaton, Fabien; Höhener, Patrick; Hunkeler, Daniel

    2011-01-01

    Analytical models were developed that simulate stable isotope ratios of volatile organic compounds (VOCs) near a point source contamination in the unsaturated zone. The models describe diffusive transport of VOCs, biodegradation and source ageing. The mass transport is governed by Fick's law for diffusion. The equation for reactive transport of VOCs in the soil gas phase was solved for different source geometries and for different boundary conditions. Model results were compared to experimental data from a one-dimensional laboratory column and a radial-symmetric field experiment. The comparison yielded a satisfying agreement. The model results clearly illustrate the significant isotope fractionation by gas phase diffusion under transient state conditions. This leads to an initial depletion of heavy isotopes with increasing distance from the source. The isotope evolution of the source is governed by the combined effects of isotope fractionation due to vaporisation, diffusion and biodegradation. The net effect can lead to an enrichment or depletion of the heavy isotope in the remaining organic phase, depending on the compound and element considered. Finally, the isotope evolution of molecules migrating away from the source and undergoing degradation is governed by a combined degradation and diffusion isotope effect. This suggests that, in the unsaturated zone, the interpretation of biodegradation of VOC based on isotopic data must always be based on a model combining gas phase diffusion and degradation.

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

    Science.gov (United States)

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

    2014-01-01

    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.

  11. Environmental chamber study of maximum incremental reactivities of volatile organic compounds

    Science.gov (United States)

    Carter, William P. L.; Pierce, John A.; Luo, Dongmin; Malkina, Irina L.

    The effects of 26 individual volatile organic compounds (VOCs) on ozone formation, NO oxidation, and OH radical levels were measured by adding them to reactive organic gas (ROG)-NO x-air environmental chamber irradiations representing a simplified model photochemical smog system. These experiments had relatively low ROG/NOx ratios to represent conditions where ozone formation is most sensitive to VOC additions. The compounds studied included representative alkanes, alkenes, aromatic hydrocarbons, aldehydes, alcohols, and CO. The addition of formaldehyde, methylbenzenes, alkenes and methanol all caused increased integrated OH radical concentrations, and caused the most NO oxidation and ozone formation per molecule reacted. The C 6+n-alkanes had the most inhibiting effects on OH radicals, and caused reduced NO oxidation and ozone formation in these experiments. The other compounds had smaller negative effects on OH radicals, but moderate positive effects on ozone formed and NO oxidized. The implications of these results in terms of the atmospheric reaction mechanisms of these compounds are discussed.

  12. Comparison of receptor models for source apportionment of volatile organic compounds in Beijing, China

    International Nuclear Information System (INIS)

    Song Yu; Dai Wei; Shao Min; Liu Ying; Lu Sihua; Kuster, William; Goldan, Paul

    2008-01-01

    Identifying the sources of volatile organic compounds (VOCs) is key to reducing ground-level ozone and secondary organic aerosols (SOAs). Several receptor models have been developed to apportion sources, but an intercomparison of these models had not been performed for VOCs in China. In the present study, we compared VOC sources based on chemical mass balance (CMB), UNMIX, and positive matrix factorization (PMF) models. Gasoline-related sources, petrochemical production, and liquefied petroleum gas (LPG) were identified by all three models as the major contributors, with UNMIX and PMF producing quite similar results. The contributions of gasoline-related sources and LPG estimated by the CMB model were higher, and petrochemical emissions were lower than in the UNMIX and PMF results, possibly because the VOC profiles used in the CMB model were for fresh emissions and the profiles extracted from ambient measurements by the two-factor analysis models were 'aged'. - VOCs sources were similar for three models with CMB showing a higher estimate for vehicles

  13. Comparison of receptor models for source apportionment of volatile organic compounds in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Song Yu; Dai Wei [Department of Environmental Sciences, Peking University, Beijing 100871 (China); Shao Min [State Joint Key Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing 100871 (China)], E-mail: mshao@pku.edu.cn; Liu Ying; Lu Sihua [State Joint Key Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing 100871 (China); Kuster, William; Goldan, Paul [Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO 80305 (United States)

    2008-11-15

    Identifying the sources of volatile organic compounds (VOCs) is key to reducing ground-level ozone and secondary organic aerosols (SOAs). Several receptor models have been developed to apportion sources, but an intercomparison of these models had not been performed for VOCs in China. In the present study, we compared VOC sources based on chemical mass balance (CMB), UNMIX, and positive matrix factorization (PMF) models. Gasoline-related sources, petrochemical production, and liquefied petroleum gas (LPG) were identified by all three models as the major contributors, with UNMIX and PMF producing quite similar results. The contributions of gasoline-related sources and LPG estimated by the CMB model were higher, and petrochemical emissions were lower than in the UNMIX and PMF results, possibly because the VOC profiles used in the CMB model were for fresh emissions and the profiles extracted from ambient measurements by the two-factor analysis models were 'aged'. - VOCs sources were similar for three models with CMB showing a higher estimate for vehicles.

  14. Malodorous volatile organic sulfur compounds: Sources, sinks and significance in inland waters.

    Science.gov (United States)

    Watson, Susan B; Jüttner, Friedrich

    2017-03-01

    Volatile Organic Sulfur Compounds (VOSCs) are instrumental in global S-cycling and greenhouse gas production. VOSCs occur across a diversity of inland waters, and with widespread eutrophication and climate change, are increasingly linked with malodours in organic-rich waterbodies and drinking-water supplies. Compared with marine systems, the role of VOSCs in biogeochemical processes is far less well characterized for inland waters, and often involves different physicochemical and biological processes. This review provides an updated synthesis of VOSCs in inland waters, focusing on compounds known to cause malodours. We examine the major limnological and biochemical processes involved in the formation and degradation of alkylthiols, dialkylsulfides, dialkylpolysulfides, and other organosulfur compounds under different oxygen, salinity and mixing regimes, and key phototropic and heterotrophic microbial producers and degraders (bacteria, cyanobacteria, and algae) in these environs. The data show VOSC levels which vary significantly, sometimes far exceeding human odor thresholds, generated by a diversity of biota, biochemical pathways, enzymes and precursors. We also draw attention to major issues in sampling and analytical artifacts which bias and preclude comparisons among studies, and highlight significant knowledge gaps that need addressing with careful, appropriate methods to provide a more robust understanding of the potential effects of continued global development.

  15. Biogenic volatile organic compound emissions along a high arctic soil moisture gradient.

    Science.gov (United States)

    Svendsen, Sarah Hagel; Lindwall, Frida; Michelsen, Anders; Rinnan, Riikka

    2016-12-15

    Emissions of biogenic volatile organic compounds (BVOCs) from terrestrial ecosystems are important for the atmospheric chemistry and the formation of secondary organic aerosols, and may therefore influence the climate. Global warming is predicted to change patterns in precipitation and plant species compositions, especially in arctic regions where the temperature increase will be most pronounced. These changes are potentially highly important for the BVOC emissions but studies investigating the effects are lacking. The aim of this study was to investigate the quality and quantity of BVOC emissions from a high arctic soil moisture gradient extending from dry tundra to a wet fen. Ecosystem BVOC emissions were sampled five times in the July-August period using a push-pull enclosure technique, and BVOCs trapped in absorbent cartridges were analyzed using gas chromatography-mass spectrometry. Plant species compositions were estimated using the point intercept method. In order to take into account important underlying ecosystem processes, gross ecosystem production, ecosystem respiration and net ecosystem production were measured in connection with chamber-based BVOC measurements. Highest emissions of BVOCs were found from vegetation communities dominated by Salix arctica and Cassiope tetragona, which had emission profiles dominated by isoprene and monoterpenes, respectively. These results show that emissions of BVOCs are highly dependent on the plant cover supported by the varying soil moisture, suggesting that high arctic BVOC emissions may affect the climate differently if soil water content and plant cover change. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

    Science.gov (United States)

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-06-09

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget.

  17. The Kinesin Adaptor Calsyntenin-1 Organizes Microtubule Polarity and Regulates Dynamics during Sensory Axon Arbor Development

    Directory of Open Access Journals (Sweden)

    Mary C. Halloran

    2017-04-01

    Full Text Available Axon growth and branching, and development of neuronal polarity are critically dependent on proper organization and dynamics of the microtubule (MT cytoskeleton. MTs must organize with correct polarity for delivery of diverse cargos to appropriate subcellular locations, yet the molecular mechanisms regulating MT polarity remain poorly understood. Moreover, how an actively branching axon reorganizes MTs to direct their plus ends distally at branch points is unknown. We used high-speed, in vivo imaging of polymerizing MT plus ends to characterize MT dynamics in developing sensory axon arbors in zebrafish embryos. We find that axonal MTs are highly dynamic throughout development, and that the peripheral and central axons of sensory neurons show differences in MT behaviors. Furthermore, we show that Calsyntenin-1 (Clstn-1, a kinesin adaptor required for sensory axon branching, also regulates MT polarity in developing axon arbors. In wild type neurons the vast majority of MTs are directed in the correct plus-end-distal orientation from early stages of development. Loss of Clstn-1 causes an increase in MTs polymerizing in the retrograde direction. These misoriented MTs most often are found near growth cones and branch points, suggesting Clstn-1 is particularly important for organizing MT polarity at these locations. Together, our results suggest that Clstn-1, in addition to regulating kinesin-mediated cargo transport, also organizes the underlying MT highway during axon arbor development.

  18. Atmospheric PM and volatile organic compounds released from Mediterranean shrubland wildfires

    Science.gov (United States)

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

    2014-06-01

    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.

  19. Emissions of volatile organic compounds from building materials and consumer products

    Science.gov (United States)

    Wallace, Lance A.; Pellizzari, Edo; Leaderer, Brian; Zelon, Harvey; Sheldon, Linda

    EPA's TEAM Study of personal exposure to volatile organic compounds (VOC) in air and drinking water of 650 residents of seven U.S. cities resulted in the identification of a number of possible sources encountered in peoples' normal daily activities and in their homes. A follow-up EPA study of publicaccess buildings implicated other potential sources of exposure. To learn more about these potential sources, 15 building materials and common consumer products were analyzed using a headspace technique to detect organic emissions and to compare relative amounts. About 10-100 organic compounds were detected offgassing from each material. Four mixtures of materials were then chosen for detailed study: paint on sheetrock; carpet and carpet glue; wallpaper and adhesives; cleansers and a spray pesticide. The materials were applied as normally used, allowed to age 1 week (except for the cleansers and pesticides, which were used normally during the monitoring period), and placed in an environmentally controlled chamber. Organic vapors were collected on Tenax-GC over a 4-h period and analyzed by GC-MS techniques. Emission rates and chamber concentrations were calculated for 17 target chemicals chosen for their toxic, carcinogenic or mutagenic properties. Thirteen of the 17 chemicals were emitted by one or more of the materials. Elevated concentrations of chloroform, carbon tetrachloride, 1,1,1-trichloroethane, n-decane, n-undecane, p-dichlorobenzene, 1,2-dichloroethane and styrene were produced by the four mixtures of materials tested. For some chemicals, these amounts were sufficient to account for a significant fraction of the elevated concentrations observed in previous indoor air studies. We conclude that common materials found in nearly every home and place of business may cause elevated exposures to toxic chemicals.

  20. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2009-06-01

    Full Text Available Green leaf volatiles (GLVs are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1–5 TgC yr−1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  1. Salt Lakes of Western Australia - Emissions of natural volatile organic compounds

    Science.gov (United States)

    Sattler, Tobias; Krause, Torsten; Schöler, Heinfried; Kamilli, Katharina; Held, Andreas; Zetzsch, Cornelius; Ofner, Johannes; Junkermann, Wolfgang; Atlas, Elliot

    2013-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many saline lakes with a wide range of hydrogeochemical parameters. This area has been repeatedly investigated since 2006 and consists of ephemeral saline and saline groundwater sourced lakes with a pH reaching from 2.5 to 7.1. The semi-/arid region was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Today the region is mostly used for growing wheat and live stock. The deforestation led to a rising groundwater table, bringing dissolved salts and minerals to the surface. In the last decades, a concurrent alteration of rain periods has been observed. A reason could be the regional formation of ultra-fine particles that were measured with car-based and airborne instruments around the salt lakes in several campaigns between 2006 and 2011. These ultra-fine particles emitted from the lakes and acting as cloud condensation nuclei can modify cloud microphysics and thus suppress rain events [1]. New data from a campaign in 2012 accentuates the importance of these hyper saline environments for the local climate. Ground-based particle measurements around the salt lakes in 2012 were accompanied by novel chamber experiments directly on the lakes. The 1.5 m³ cubic chamber was constructed from transparent PTFE foil permitting photochemistry within while preventing dilution of the air due to lateral wind transport. This experimental setup allows linking the measured data directly to the chemistry of and above the salt lakes. Another advantage of the PTFE chamber is the enrichment of volatile organic compounds (VOC) that are emitted from salt lakes as possible precursors for the ultra-fine particles. Chamber air was sampled using stainless steel canisters. Sediment, crust and water samples were taken for investigation of potential VOC emissions in

  2. Emission of volatile organic compounds from silage: Compounds, sources, and implications

    Science.gov (United States)

    Hafner, Sasha D.; Howard, Cody; Muck, Richard E.; Franco, Roberta B.; Montes, Felipe; Green, Peter G.; Mitloehner, Frank; Trabue, Steven L.; Rotz, C. Alan

    2013-10-01

    Silage, fermented cattle feed, has recently been identified as a significant source of volatile organic compounds (VOCs) to the atmosphere. A small number of studies have measured VOC emission from silage, but not enough is known about the processes involved to accurately quantify emission rates and identify practices that could reduce emissions. Through a literature review, we have focused on identifying the most important compounds emitted from corn silage (the most common type of silage in the US) and the sources of these compounds by quantifying their production and emission potential in silage and describing production pathways. We reviewed measurements of VOC emission from silage and assessed the importance of individual silage VOCs through a quantitative analysis of VOC concentrations within silage. Measurements of VOC emission from silage and VOCs present within silage indicated that alcohols generally make the largest contribution to emission from corn silage, in terms of mass emitted and potential ozone formation. Ethanol is the dominant alcohol in corn silage; excluding acids, it makes up more than half of the mean mass of VOCs present. Acids, primarily acetic acid, may be important when emission is high and all VOCs are nearly depleted by emission. Aldehydes and esters, which are more volatile than acids and alcohols, are important when exposure is short, limiting emission of more abundant but less volatile compounds. Variability in silage VOC concentrations is very high; for most alcohols and acids, tolerance intervals indicate that 25% of silages have concentrations a factor of two away from median values, and possibly much further. This observation suggests that management practices can significantly influence VOC concentrations. Variability also makes prediction of emissions difficult. The most important acids, alcohols, and aldehydes present in silage are probably produced by bacteria (and, in the case of ethanol, yeasts) during fermentation and

  3. Release and uptake of volatile organic compounds by human hepatocellular carcinoma cells (HepG2) in vitro.

    Science.gov (United States)

    Mochalski, Paweł; Sponring, Andreas; King, Julian; Unterkofler, Karl; Troppmair, Jakob; Amann, Anton

    2013-07-17

    Volatile organic compounds (VOCs) emitted by human body offer a unique insight into biochemical processes ongoing in healthy and diseased human organisms. Unfortunately, in many cases their origin and metabolic fate have not been yet elucidated in sufficient depth, thus limiting their clinical application. The primary goal of this work was to identify and quantify volatile organic compounds being released or metabolized by HepG2 hepatocellular carcinoma cells. The hepatocellular carcinoma cells were incubated in specially designed head-space 1-L glass bottles sealed for 24 hours prior to measurements. Identification and quantification of volatiles released and consumed by cells under study were performed by gas chromatography with mass spectrometric detection (GC-MS) coupled with head-space needle trap device extraction (HS-NTD) as the pre-concentration technique. Most of the compounds were identified both by spectral library match as well as retention time comparison based on standards. A total of nine compounds were found to be metabolised and further twelve released by the cells under study (Wilcoxon signed-rank test, p3-octanone, 2-nonanone), five volatile sulphur compounds (dimethyl sulfide, ethyl methyl sulfide, 3-methyl thiophene, 2-methyl-1-(methylthio)- propane and 2-methyl-5-(methylthio) furan), n-propyl acetate, and 2-heptene. The emission and uptake of the aforementioned VOCs may reflect the activity of abundant liver enzymes and support the potential of VOC analysis for the assessment of enzymes function.

  4. Determination of Volatile Organic Compounds in Fourty Five Salvia Species by Thermal Desorption-GC-MS Technique

    Directory of Open Access Journals (Sweden)

    Seda Damla Hatipoglu

    2016-05-01

    Full Text Available Volatile organic compounds (VOC from dried aerial parts (flowers, leafs, leafy branches and stems of fourty five Salvia species, harvested from different regions of Turkey, were determined using thermal desorption technique coupled to gas chromatography-mass spectrometer (TD-GC-MS. Total percentages of the detected volatile organic compounds of the Salvia species ranged from 70.30 to 99.65% . Total yield of VOC was found to be highly variable among Salvia species, and the percentage of each component also exhibited high variation. While sesquiterpene hydrocarbons represented 0.90-45.02% of the volatile organic compounds, the others were found to be monoterpene hydrocarbons 0.00-32.25%, monoterpenoids 0.94- 53.60%, sesquiterpenoids 0.00- 31.45% and hydrocarbons and derivatives 2.99-46.87%. The rest of the composition consisted of diterpene alcohols, fatty acids, phenolics and triterpenes. In total, 108 volatile compounds were identified from studied 45 Anatolian Salvia species.

  5. Diffusive transport of organic vapors in the unsaturated zone with kinetically-controlled volatilization and dissolution: analytical model and analysis

    Science.gov (United States)

    Zaidel, Jacob; Russo, David

    1994-12-01

    Kinetically-controlled volatilization and dissolution of nonaqueous-phase liquids (NAPL's) in the unsaturated (vadose) zone are a more general model as compared to the usually used local equilibrium model of mass transfer. This paper presents a one-dimensional vertical model of kinetically-controlled diffusive transport of organic vapors pertinent to pollution caused by a relatively long, ground surface-originating, mainly horizontally-spread leak of NAPL, the volatile compound of which undergoes sorption and degradation in the soil. Analytical solutions of this model are applicable to homogeneous soils with ground surface fully open to the atmosphere. Application of the solutions to several examples demonstrates the role of kinetically-controlled volatilization and dissolution at both early and advanced stages of the transport process. Asymptotic analysis of the outlined solutions is employed in order to examine the depletion of the contaminant source.

  6. Origin and variability in volatile organic compounds observed at an Eastern Mediterranean background site (Cyprus)

    Science.gov (United States)

    Debevec, Cécile; Sauvage, Stéphane; Gros, Valérie; Sciare, Jean; Pikridas, Michael; Stavroulas, Iasonas; Salameh, Thérèse; Leonardis, Thierry; Gaudion, Vincent; Depelchin, Laurence; Fronval, Isabelle; Sarda-Esteve, Roland; Baisnée, Dominique; Bonsang, Bernard; Savvides, Chrysanthos; Vrekoussis, Mihalis; Locoge, Nadine

    2017-09-01

    More than 7000 atmospheric measurements of over 60 C2 - C16 volatile organic compounds (VOCs) were conducted at a background site in Cyprus during a 1-month intensive field campaign held in March 2015. This exhaustive dataset consisted of primary anthropogenic and biogenic VOCs, including a wide range of source-specific tracers, and oxygenated VOCs (with various origins) that were measured online by flame ionization detection-gas chromatography and proton transfer mass spectrometry. Online submicron aerosol chemical composition was performed in parallel using an aerosol mass spectrometer. This study presents the high temporal variability in VOCs and their associated sources. A preliminary analysis of their time series was performed on the basis of independent tracers (NO, CO, black carbon), meteorological data and the clustering of air mass trajectories. Biogenic compounds were mainly attributed to a local origin and showed compound-specific diurnal cycles such as a daily maximum for isoprene and a nighttime maximum for monoterpenes. Anthropogenic VOCs as well as oxygenated VOCs displayed higher mixing ratios under the influence of continental air masses (i.e., western Asia), indicating that long-range transport significantly contributed to the VOC levels in the area. Source apportionment was then conducted on a database of 20 VOCs (or grouped VOCs) using a source receptor model. The positive matrix factorization and concentration field analyses were hence conducted to identify and characterize covariation factors of VOCs that were representative of primary emissions as well as chemical transformation processes. A six-factor PMF solution was selected, namely two primary biogenic factors (relative contribution of 43 % to the total mass of VOCs) for different types of emitting vegetation; three anthropogenic factors (short-lived combustion source, evaporative sources, industrial and evaporative sources; 21 % all together), identified as being either of local origin

  7. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, Eric; Emmons, L.; Karl, Thomas G.; Flocke, Frank M.; Hills, A. J.; Madronich, Sasha; Lee-Taylor, J.; Fried, Alan; Weibring, P.; Walega, J.; Richter, Dirk; Tie, X.; Mauldin, L.; Campos, Teresa; Weinheimer, Andrew J.; Knapp, David; Sive, B.; Kleinman, Lawrence I.; Springston, S.; Zaveri, Rahul A.; Ortega, John V.; Voss, Paul B.; Blake, D. R.; Baker, Angela K.; Warneke, Carsten; Welsh-Bon, Daniel; de Gouw, Joost A.; Zheng, J.; Zhang, Renyi; Rudolph, Jochen; Junkermann, W.; Riemer, D.

    2010-01-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on March 18 and the NCAR C130 one day later on March 19. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the March 19 plume and to help interpret the OH

  8. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, E.; Springston, S.; Karl, T.; Emmons, L.; Flocke, F.; Hills, A. J.; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D., Tie, X.; Mauldin, L.; Campos, T.; Sive, B.; Kleinman, L.; Springston, S., Zaveri, R.; deGouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

    2009-11-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on 18 March and the NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the 19 March plume and to help interpret the OH

  9. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Directory of Open Access Journals (Sweden)

    E. C. Apel

    2010-03-01

    Full Text Available The volatile organic compound (VOC distribution in the Mexico City Metropolitan Area (MCMA and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs but with a substantial contribution from oxygenated volatile organic compounds (OVOCs, predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry model and MOZART (Model for Ozone and Related chemical Tracers were able to approximate the observed MCMA daytime patterns and absolute values of the VOC OH reactivity. The MOZART model is also in agreement with observations showing that NMHCs dominate the reactivity distribution except in the afternoon hours. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height.

    A northeast transport event was studied in which air originating in the MCMA was intercepted aloft with the Department of Energy (DOE G1 on 18 March and downwind with the National Center for Atmospheric Research (NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind; ozone was shown to be photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial extent and temporal evolution of the plume

  10. Fabrication of novel nanoporous array anodic alumina solid-phase microextraction fiber coating and its potential application for headspace sampling of biological volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhuomin [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Wang Qingtang [Key Laboratory of Analysis and Detection for Food Safety of Ministry of Education, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou, Fujian 350002 (China); Li Gongke, E-mail: cesgkl@mail.sysu.edu.cn [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2012-05-21

    Highlights: Black-Right-Pointing-Pointer Nanoporous array anodic alumina (NAAA) SPME coating was originally prepared. Black-Right-Pointing-Pointer NAAA SPME coating achieved excellent enrichment capability and selectivity for VOCs. Black-Right-Pointing-Pointer NAAA SPME coating can be applied for the headspace sampling of biological VOCs. - Abstract: In the study, nanoporous array anodic alumina (NAAA) prepared by a simple, rapid and stable two-step anodic oxidization method was introduced as a novel solid-phase microextraction (SPME) fiber coating. The regular nanoporous array structure and chemical composition of NAAA SPME fiber coating was characterized and validated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Compared with the commercial polydimethylsiloxane (PDMS) SPME fiber coating, NAAA SPME fiber coating achieved the higher enrichment capability (1.7-4.7 folds) for the mixed standards of volatile organic compounds (VOCs). The selectivity for volatile alcohols by NAAA SPME fiber coating demonstrated an increasing trend with the increasing polarity of alcohols caused by the gradually shortening carbon chains from 1-undecanol to 1-heptanol or the isomerization of carbon chains of some typical volatile alcohols including 2-ethyl hexanol, 1-octanol, 2-phenylethanol, 1-phenylethanol, 5-undecanol, 2-undecanol and 1-undecanol. Finally, NAAA SPME fiber coating was originally applied for the analysis of biological VOCs of Bailan flower, stinkbug and orange peel samples coupled with gas chromatography-mass spectrometry (GC-MS) detection. Thirty, twenty-seven and forty-four VOCs of Bailan flower, stinkbug and orange peel samples were sampled and identified, respectively. Moreover, the contents of trace 1-octanol and nonanal of real orange peel samples were quantified for the further method validation with satisfactory recoveries of 106.5 and 120.5%, respectively. This work proposed a sensitive, rapid, reliable and convenient

  11. Fabrication of novel nanoporous array anodic alumina solid-phase microextraction fiber coating and its potential application for headspace sampling of biological volatile organic compounds

    International Nuclear Information System (INIS)

    Zhang Zhuomin; Wang Qingtang; Li Gongke

    2012-01-01

    Highlights: ► Nanoporous array anodic alumina (NAAA) SPME coating was originally prepared. ► NAAA SPME coating achieved excellent enrichment capability and selectivity for VOCs. ► NAAA SPME coating can be applied for the headspace sampling of biological VOCs. - Abstract: In the study, nanoporous array anodic alumina (NAAA) prepared by a simple, rapid and stable two-step anodic oxidization method was introduced as a novel solid-phase microextraction (SPME) fiber coating. The regular nanoporous array structure and chemical composition of NAAA SPME fiber coating was characterized and validated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Compared with the commercial polydimethylsiloxane (PDMS) SPME fiber coating, NAAA SPME fiber coating achieved the higher enrichment capability (1.7–4.7 folds) for the mixed standards of volatile organic compounds (VOCs). The selectivity for volatile alcohols by NAAA SPME fiber coating demonstrated an increasing trend with the increasing polarity of alcohols caused by the gradually shortening carbon chains from 1-undecanol to 1-heptanol or the isomerization of carbon chains of some typical volatile alcohols including 2-ethyl hexanol, 1-octanol, 2-phenylethanol, 1-phenylethanol, 5-undecanol, 2-undecanol and 1-undecanol. Finally, NAAA SPME fiber coating was originally applied for the analysis of biological VOCs of Bailan flower, stinkbug and orange peel samples coupled with gas chromatography–mass spectrometry (GC–MS) detection. Thirty, twenty-seven and forty-four VOCs of Bailan flower, stinkbug and orange peel samples were sampled and identified, respectively. Moreover, the contents of trace 1-octanol and nonanal of real orange peel samples were quantified for the further method validation with satisfactory recoveries of 106.5 and 120.5%, respectively. This work proposed a sensitive, rapid, reliable and convenient analytical method for the potential study of trace and small molecular

  12. Recycling of red mud waste for use as a catalyst for eliminating volatile organic compounds; Recyclage d'un dechet, une boue rouge, comme catalyseur pour l'elimination des composes organiques volatils

    Energy Technology Data Exchange (ETDEWEB)

    Lamonier, J.F.; Wyrwalski, F.; Aboukais, A. [Univ. du Littoral Cote d' Opale, Dunkerque (France). Laboratoire de Catalyse et Environnement; Leclercq, G. [Univ. des Sciences et Technologies de Lille, Villeneuve d' Ascq (France). Laboratoire de Catalyse de Lille

    2005-08-01

    Red mud is a waste product of the aluminium refining industry. It is composed of aluminium hydroxide and iron oxide. This study examined the feasibility of using red mud as a catalyst to eliminate volatile organic compounds in atmospheric pollutants. Volatile organic compounds can be eliminated by thermal oxidation between 600 and 1100 degrees C. However, the oxidation of volatile organic compounds can also be accomplished at lower temperatures (200 to 450 degrees C) if a catalyst is present. Currently, the low temperature destruction of volatile organic compounds is not widespread because of the difficulty in deactivating the catalyst. In this study, red mud was calcined in air at 500 degrees C. Under such conditions, the red mud converts to aluminium oxide and iron oxide. These 2 oxides are active and are carbon dioxide selective in the oxidation of volatile organic compounds. The study showed that red mud can be used as a catalyst for the oxidation of toluene. The amount of iron oxide in the red mud determines its activity and selectivity in the oxidation reaction. Considering the low cost of red mud waste, this material can be used as a catalyst for both the destruction and bi-oxidation of volatile organic compounds. 10 refs., 2 tabs., 3 figs.

  13. Long-term stability measurements of low concentration Volatile Organic Compound gas mixtures

    Science.gov (United States)

    Allen, Nick; Amico di Meane, Elena; Brewer, Paul; Ferracci, Valerio; Corbel, Marivon; Worton, David

    2017-04-01

    VOCs (Volatile Organic Compounds) are a class of compounds with significant influence on the atmosphere due to their large anthropogenic and biogenic emission sources. VOC emissions have a significant impact on the atmospheric hydroxyl budget and nitrogen reservoir species, while also contributing indirectly to the production of tropospheric ozone and secondary organic aerosol. However, the global budget of many of these species are poorly constrained. Moreover, the World Meteorological Organization's (WMO) Global Atmosphere Watch (GAW) have set challenging data quality objectives for atmospheric monitoring programmes for these classes of traceable VOCs, despite the lack of available stable gas standards. The Key-VOCs Joint Research Project is an ongoing three-year collaboration with the aim of improving the measurement infrastructure of important atmospheric VOCs by providing traceable and comparable reference gas standards and by validating new measurement systems in support of the air monitoring networks. It focuses on VOC compounds that are regulated by European legislation, that are relevant for indoor air monitoring and for air quality and climate monitoring programmes like the VOC programme established by the WMO GAW and the European Monitoring and Evaluation Programme (EMEP). These VOCs include formaldehyde, oxy[genated]-VOCs (acetone, ethanol and methanol) and terpenes (a-pinene, 1,8-cineole, δ-3-carene and R-limonene). Here we present the results of a novel long term stability study for low concentration formaldehyde, oxy-VOC and terpenes gas mixtures produced by the Key-VOCs consortium with discussion regarding the implementation of improved preparation techniques and the use of novel cylinder passivation chemistries to guarantee mixture stability.

  14. Toxicity of natural mixtures of organic pollutants in temperate and polar marine phytoplankton

    KAUST Repository

    Echeveste, Pedro

    2016-07-26

    Semivolatile and persistent organic pollutants (POPs) undergo atmospheric transport before being deposited to the oceans, where they partition to phytoplankton organic matter. The goal of this study was to determine the toxicity of naturally occurring complex mixtures of organic pollutants to temperate and polar phytoplankton communities from the Mediterranean Sea, the North East (NE) Atlantic, and Southern Oceans. The cell abundance of the different phytoplankton groups, chlorophyll a concentrations, viability of the cells, and growth and decay constants were monitored in response to addition of a range of concentrations of mixtures of organic pollutants obtained from seawater extracts. Almost all of the phytoplankton groups were significantly affected by the complex mixtures of non-polar and polar organic pollutants, with toxicity being greater for these mixtures than for single POPs or simple POP mixtures. Cocktails\\' toxicity arose at concentrations as low as tenfold the field oceanic levels, probably due to a higher chemical activity of the mixture than of simple POPs mixtures. Overall, smaller cells were the most affected, although Mediterranean picophytoplankton was significantly more tolerant to non-polar POPs than picophytoplankton from the Atlantic Ocean or the Bellingshausen Sea microphytoplankton. © 2016 Elsevier B.V.

  15. Decomposition of volatile organic compounds and polycyclic aromatic hydrocarbons in industrial off-gas by electron beams: A review

    International Nuclear Information System (INIS)

    Paur, H.R.

    1998-01-01

    The electron beam induced decomposition of volatile organic compounds (e.g. aromatic compounds, esters, chlorinated hydrocarbons) and polycyclic aromatic hydrocarbons (e.g. chlorinated dibenzo-dioxins) in industrial off gas has been investigated by several research groups in Germany and Japan. The method was shown to be effective for cleaning the waste gas of a paint factory, the waste air discharged from an automobile tunnel, the off gas cleaning from a groundwater remediation plant and the flue gas of a waste incinerator. The electron beam process achieves high removal efficiencies for volatile organic compounds. Reaction models have been developed, which suggest that the organic compounds are oxidized by hydroxyl radicals. The electron beam process may treat very large off-gas volumes at ambient temperatures and has a low energy consumption. The production of secondary wastes can be avoided or minimized. Compared to conventional methods the investment and operation costs of the process seem to be attractive for selected applications

  16. Measurements of Volatile Organic Compounds and Gaseous Sulfuric Acid During the 2008 CAREBEIJING Campaign

    Science.gov (United States)

    Zhang, R.; Zheng, J.; Hu, M.; Zhu, T.

    2009-05-01

    Air quality in Beijing has been a hot topic recently, because Beijing hosted the 2008 summer Olympics. To combat the problem, China ordered numerous factories shut down or used only sporadically during the games to limit air pollution in the area. Another major step involved ordering about one-half of the city's 3.3 million vehicles off the road during the games, allowing only cars on roads with odd or even-numbered license plates on alternate days until the games were over. In addition, China has implemented new auto emission standards since March 2009 with regulations that are similar to those used throughout Europe. Our team at the Texas A&M participated in the 2008 CAREBEIJING campaign, with the objectives of studying the complex chemistry of the air in Beijing, looking at emission controls and their effectiveness, studying the surrounding air from other regions and how it can affect Beijing's air, and comparing all of our findings with air quality in other cities we have examined, such as Mexico City and Houston. In this talk, preliminary results of measurements of volatile organic compounds (VOCs) and gaseous sulfuric acid will be presented to discuss the trends of VOCs and new particle formation associated with the traffic control.

  17. UNMIX Methods Applied to Characterize Sources of Volatile Organic Compounds in Toronto, Ontario

    Directory of Open Access Journals (Sweden)

    Eugeniusz Porada

    2016-06-01

    Full Text Available UNMIX, a sensor modeling routine from the U.S. Environmental Protection Agency (EPA, was used to model volatile organic compound (VOC receptors in four urban sites in Toronto, Ontario. VOC ambient concentration data acquired in 2000–2009 for 175 VOC species in four air quality monitoring stations were analyzed. UNMIX, by performing multiple modeling attempts upon varying VOC menus—while rejecting the results that were not reliable—allowed for discriminating sources by their most consistent chemical characteristics. The method assessed occurrences of VOCs in sources typical of the urban environment (traffic, evaporative emissions of fuels, banks of fugitive inert gases, industrial point sources (plastic-, polymer-, and metalworking manufactures, and in secondary sources (releases from water, sediments, and contaminated urban soil. The remote sensing and robust modeling used here produces chemical profiles of putative VOC sources that, if combined with known environmental fates of VOCs, can be used to assign physical sources’ shares of VOCs emissions into the atmosphere. This in turn provides a means of assessing the impact of environmental policies on one hand, and industrial activities on the other hand, on VOC air pollution.

  18. Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest

    Directory of Open Access Journals (Sweden)

    H. Aaltonen

    2012-06-01

    Full Text Available Soil provides an important source of volatile organic compounds (VOCs to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L. forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations varying from 0.11 to 16 μg m−3. Sesquiterpenes and oxygen-containing monoterpenes were also detected. Inside the pristine snowpack, the concentrations of terpenoids decreased from soil surface towards the surface of the snow, suggesting soil as the source for terpenoids. Forest damages (i.e. broken treetops and branches, fallen trees resulting from heavy snow loading during the measurement period increased the terpenoid concentrations dramatically, especially in the upper part of the snowpack. The results show that soil processes are active and efficient VOC sources also during winter, and that natural or human disturbance can increase forest floor VOC concentrations substantially. Our results stress the importance of soil as a source of VOCs during the season when other biological sources, such as plants, have lower activity.

  19. Volatile organic compound emissions from switchgrass cultivars used as biofuel crops

    Science.gov (United States)

    Eller, A. S. D.; Sekimoto, K.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; Monson, R. K.; Graus, M.; Crespo, E.; Warneke, C.; Fall, R.

    2011-06-01

    Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for switchgrass (Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) biofuel production and the acreage dedicated to its growth in the USA has already increased during the past decade. We estimate that the yearly emissions from switchgrass plantations, including both the growth and harvest phases will be on the order of 3 kg C ha-1 methanol, 1 kg C ha-1 acetaldehyde, 1 kg C ha-1 acetone, 0.9 kg C ha-1 monoterpenes, 0.5 kg C ha-1 isoprene + another compound, most likely 1-penten-3-ol, 0.2 kg C ha-1 hexenals, and 0.1 kg C ha-1 hexenols. These emission rates are much lower than those expected from Eucalyptus or poplar plantations, which are other potential biofuel crops and have significantly higher VOC emissions, suggesting that the choice of species in the production of biofuels could have serious implications for regional air quality.

  20. Volatile organic compound emissions from elephant grass and bamboo cultivars used as potential bioethanol crop

    Science.gov (United States)

    Crespo, E.; Graus, M.; Gilman, J. B.; Lerner, B. M.; Fall, R.; Harren, F. J. M.; Warneke, C.

    2013-02-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-15

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

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

    International Nuclear Information System (INIS)

    Mohd Pauzi Abdullah; Chian, S.S.

    2011-01-01

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

  3. Volatile Organic Compounds in Exhaled Breath of Idiopathic Pulmonary Fibrosis for Discrimination from Healthy Subjects.

    Science.gov (United States)

    Yamada, Yu-Ichi; Yamada, Gen; Otsuka, Mitsuo; Nishikiori, Hirotaka; Ikeda, Kimiyuki; Umeda, Yasuaki; Ohnishi, Hirofumi; Kuronuma, Koji; Chiba, Hirofumi; Baumbach, Jörg Ingo; Takahashi, Hiroki

    2017-04-01

    Purpose Human breath analysis is proposed with increasing frequency as a useful tool in clinical application. We performed this study to find the characteristic volatile organic compounds (VOCs) in the exhaled breath of patients with idiopathic pulmonary fibrosis (IPF) for discrimination from healthy subjects. Methods VOCs in the exhaled breath of 40 IPF patients and 55 healthy controls were measured using a multi-capillary column and ion mobility spectrometer. The patients were examined by pulmonary function tests, blood gas analysis, and serum biomarkers of interstitial pneumonia. Results We detected 85 VOC peaks in the exhaled breath of IPF patients and controls. IPF patients showed 5 significant VOC peaks; p-cymene, acetoin, isoprene, ethylbenzene, and an unknown compound. The VOC peak of p-cymene was significantly lower (p VOC peaks of acetoin, isoprene, ethylbenzene, and the unknown compound were significantly higher (p VOC peaks with clinical parameters, negative correlations with VC (r =-0.393, p = 0.013), %VC (r =-0.569, p VOCs in the exhaled breath of IPF patients. Among them, the VOC peaks of p-cymene were related to the clinical parameters of IPF. These VOCs may be useful biomarkers of IPF.

  4. Producing surfactant-synthesized nanomaterials in situ on a building substrate, without volatile organic compounds.

    Science.gov (United States)

    Illescas, Juan F; Mosquera, Maria J

    2012-08-01

    This article describes a sol-gel route for nanomaterials production, without volatile organic compounds (VOCs). These materials are simply obtained by mixing a silica oligomer with a non-ionic surfactant under ultrasonic agitation. The surfactant acts as sol-gel transition catalyst and also as an agent that directs the pore structure of the material, reducing capillary pressure during drying. Thus, a crack-free monolithic material is produced. We also synthesize a novel product with hydrophobic properties by adding OH terminal-polydimethylsiloxane to the starting sol. Importantly, since our synthesis does not require calcination or other additional procedures, the sol can be applied directly onto substrates, particularly the external surface of buildings. Thus, an application of these nanomaterials is to restore and to protect building substrates. Our in-depth investigation of the structure of these materials, using several techniques (physisorption, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, nuclear resonance magnetic spectroscopy), reveals that they are composed of silica particles as a result of the role played by n-octylamine. In the hybrid materials, polydimethylsiloxane acts to form bridges linking the silica particles. Finally, we demonstrate the effectiveness of these products for consolidating one particular building stone and making it hydrophobic.

  5. Integrated gas chromatography for ultrafast analysis of volatile organic compounds in air.

    Science.gov (United States)

    Zhang, Yanggang; Wu, Dapeng; Yan, Xiaohui; Ding, Kun; Guan, Yafeng

    2016-07-01

    An integrated instrumentation of a cryogenic microtrap-thermal desorption-low thermal mass (LTM) fast gas chromatographic (GC) system had been designed and evaluated for the ultrafast enrichment and separation of trace amounts of highly volatile organic compounds (VOCs) in air. The LTM fast GC column was wrapped uniformly on outer surface of a thin metal heating cylinder of 65mm O.D. and 0.5mm in thickness. Both of microtrap and LTM column could be rapidly cooled by liquid CO2 down to -35°C, and heated by resistive heating. A 10m×100µm i.d. micro-bore capillary column was used in the LTM GC column module to provide a high separation speed. Key operational parameters, including adsorbent mass, trapping temperature, thermal desorption temperature and injection time were optimized. Under the optimized condition, the 39 species of TO-14 VOCs were well resolved and quantified in less than 3min. The detection limits were in the range of 8 ppt-0.22 ppb at sampling volume of 50mL and trapping temperature of -10°C. The average peak width was 0.9s, and the peak capacity of ~150 (at unit resolution) was obtained. The applicability of the setup was evaluated by analyzing three real environmental samples, where some typical VOCs at sub ppb level were detected. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Iterative trapping of gaseous volatile organic compounds in a capillary column.

    Science.gov (United States)

    Ghosh, Abhijit; Seeley, Stacy K; Seeley, John V

    2014-07-15

    The iterative trapping method has been developed for concentrating gaseous volatile organic compounds (VOCs) prior to gas chromatographic analysis. VOCs are trapped in a 50 cm × 0.53 mm metal capillary column coated with a 7 μm thick film of polydimethylsiloxane (PDMS). Iterative trapping does not employ the two-step thermal desorption approach used by most VOC concentrating techniques. Instead, a four-step cycle involving synchronized changes in flow direction and temperature is repeated throughout the sampling process. This iterative process causes VOCs to accumulate within the capillary well past the level where a standard two-step method reaches its saturation limit. Iterative trapping is capable of sampling and desorbing C5 through C11 n-alkanes with uniform efficiency. This new technique, in its current form, is most appropriate for focusing VOCs from gas volumes on the order of 10 mL. Iterative trapping increases the focusing power of a weak sorbent like PDMS and allows narrow chromatographic peaks to be generated without the use of high desorption temperatures or a secondary focusing stage.

  7. [Volatile organic compounds concentrations and sources inside new air-conditioned bus].

    Science.gov (United States)

    You, Ke-Wei; Ge, Yun-Shan; Qian, Yi-Xin; Liu, Wei; Feng, Bo; Zhang, Yan-Ni; Ning, Zhan-Wu; Hu, Bin; Zhao, Shou-Tang

    2008-05-01

    The distributing profile and concentration level inside new air-conditioned buses with 53 seats have been determined using the method of thermal desorption-capillary GC/MS under vehicle static conditions. Compounds were identified from their mass spectral data by using US National Institute of Standards and Technology (NIST02). The total numbers of identified components were 33 inside buses, including alkenes (15,45.4%), aromatic compounds (9,27.3%), alcohols (4,12.1%), ketones (3,9.1%) and esters (2,6.1%), especially in the range of C6-C10. The top 5 compounds measured inside buses were decane (8.01 mg/m3), 3-methylhexane (7.10 mg/m3), heptane (5.10 mg/m3), isoheptane (4.20 mg/m3) and 1-Methyl-3-ethylbenzene (3.56 mg/m3), and total volatile organic compounds (TVOC) > 52.5 mg/m3. The main sources of in-vehicle hydrocarbons and aromatic compounds comes from cabin components and interior trim materials (e.g., sealants, carpets, adhesives, paints, leather, plastics, PU foam and PE foam) that may retain certain VOCs during manufacturing, and/or emit these compounds over an extended period of time from off-gassing, aging-related breakdown products, heating/cooling and so on.

  8. Symptoms of mothers and infants related to total volatile organic compounds in household products.

    Science.gov (United States)

    Farrow, Alexandra; Taylor, Hazel; Northstone, Kate; Golding, Jean

    2003-10-01

    The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that approximated 6 mo of pregnancy and the infants' first 6 mo of life. This paper presents (a) the mothers' self-reports of the use of these products in their homes and (b) self-reported medical symptoms of mothers and infants postnatally. Higher TVOC levels were associated with air freshener and aerosol use. Infant diarrhea and earache were statistically significantly associated with air freshener use, and diarrhea and vomiting were significantly associated with aerosol use. Headache experienced by mothers 8 mo after birth was significantly associated with the use of air fresheners and aerosols; maternal depression was significantly associated with the use of air fresheners. The results of the study suggest a link between the use of products that raise indoor levels of TVOCs and an increased risk of certain symptoms among infants and their mothers.

  9. Application of headspace for research volatile organic compounds emitted from building materials

    Directory of Open Access Journals (Sweden)

    Kultys Beata

    2018-01-01

    Full Text Available Headspace technique and gas chromatography method with mas detector has been used for the determination of volatile organic compounds (VOC emitted from various building and finishing materials, such as sealing foams, mounting strips, paints, varnishes, floor coverings. The tests were carried out for different temperatures (in the temperature range of 60 to 180 °C and the time of heated vials with tested materials inside. These tests were conducted to verify the possibility of use this method of determination the VOC emission. Interpretation of chromatograms and mass spectra allowed to identify the type of compounds emitted from the tested materials and the optimum time and temperature for each type of material was determined. The increase in heating temperature of the samples resulted in increase the type and number of identified compounds: for four materials the increase was in the whole temperature range, for others it was from 90 °C. On the other hand, emission from mineral wool was low in whole temperature range. 30-minutes heating of the samples was sufficient to identify emitted compounds for most of tested materials. Applying a longer time, i.e. 24 hours, significantly increased the sensitivity of the method.

  10. Atomic and molecular physics of plasma-based environmental technologies for abatement of volatile organic compounds

    International Nuclear Information System (INIS)

    Penetrante, B.M.; Hsiao, M.C.; Bardsley, J.N.; Merrit, B.T.; Vogtlin, G.E.; Kuthi, A.; Burkhart, C.P.; Bayless, J.R.

    1996-01-01

    Non-thermal plasma techniques represent a new generation of air emission control technology that potentially could treat large-volume emissions containing dilute concentrations of volatile organic compounds (VOCs). In order to apply non-thermal in an industrial scale, it is important to establish the electrical power requirements and byproducts of the process. There is a need for reliable data concerning the primary decomposition mechanisms and subsequent chemical kinetics associated with non-thermal plasma processing of VOCs. There are many basic atomic and molecular physics issues that are essential in evaluating the economic performance of non-thermal plasma reactor. These studies are important in understanding how the input electrical power is dissipated in the plasma and how efficiency it is converted to the production of the plasma species (radicals, ions or electrons) responsible for the decomposition of the VOCs. This paper presents results from basic experimental and theoretical studied aimed at identifying the reaction mechanisms responsible for the primary decomposition of various types of VOCs. (Authors)

  11. Control of the Intrinsic Sensor Response to Volatile Organic Compounds with Fringing Electric Fields.

    Science.gov (United States)

    Henning, Alex; Swaminathan, Nandhini; Vaknin, Yonathan; Jurca, Titel; Shimanovich, Klimentiy; Shalev, Gil; Rosenwaks, Yossi

    2018-01-26

    The ability to control surface-analyte interaction allows tailoring chemical sensor sensitivity to specific target molecules. By adjusting the bias of the shallow p-n junctions in the electrostatically formed nanowire (EFN) chemical sensor, a multiple gate transistor with an exposed top dielectric layer allows tuning of the fringing electric field strength (from 0.5 × 10 7 to 2.5 × 10 7 V/m) above the EFN surface. Herein, we report that the magnitude and distribution of this fringing electric field correlate with the intrinsic sensor response to volatile organic compounds. The local variations of the surface electric field influence the analyte-surface interaction affecting the work function of the sensor surface, assessed by Kelvin probe force microscopy on the nanometer scale. We show that the sensitivity to fixed vapor analyte concentrations can be nullified and even reversed by varying the fringing field strength, and demonstrate selectivity between ethanol and n-butylamine at room temperature using a single transistor without any extrinsic chemical modification of the exposed SiO 2 surface. The results imply an electric-field-controlled analyte reaction with a dielectric surface extremely compelling for sensitivity and selectivity enhancement in chemical sensors.

  12. Remote sensing of microbial volatile organic compounds with a bioluminescent bioreporter integrated circuit

    Science.gov (United States)

    Ripp, Steven A.; Daumer, Kathleen A.; Garland, Jay L.; Simpson, Michael L.; Sayler, Gary S.

    2004-03-01

    As a means towards advanced, early-warning detection of microbial growth in enclosed structures, we have constructed a bioluminescent bioreporter for the detection of the microbial volatile organic compound (MVOC) p-cymene. MVOCs are produced as metabolic by-products of bacteria and fungi and are detectable before any visible signs of microbial growth appear, thereby serving as very early indicators of potential biocontamination problems. The bioreporter, designated Pseudomonas putida UT93, contains a Vibrio fischeri luxCDABE gene fusion to a p-cymene/p-cumate inducible promoter. Exposure of strain UT93 to p-cymene from approximately 0.02 to 850 ppm produced self-generated bioluminescence in less than 1.5 hours. The bioreporter was also interfaced with an integrated circuit microluminometer to create a miniaturized hybrid sensor for remote monitoring of p-cymene signatures. This bioluminescent bioreporter integrated circuit (BBIC) device was capable of detecting fungal presence within approximately 3.5 hours of initial exposure to Penicillium roqueforti.

  13. Assessment of predictivity of volatile organic compounds carcinogenicity and mutagenicity by freeware in silico models.

    Science.gov (United States)

    Guerra, Lília Ribeiro; de Souza, Alessandra Mendonça Teles; Côrtes, Juliana Alves; Lione, Viviane de Oliveira Freitas; Castro, Helena Carla; Alves, Gutemberg Gomes

    2017-12-01

    The application of in silico methods is increasing on toxicological risk prediction for human and environmental health. This work aimed to evaluate the performance of three in silico freeware models (OSIRIS v.2.0, LAZAR, and Toxtree) on the prediction of carcinogenicity and mutagenicity of thirty-eight volatile organic compounds (VOC) related to chemical risk assessment for occupational exposure. Theoretical data were compared with assessments available in international databases. Confusion matrices and ROC curves were used to evaluate the sensitivity, specificity, and accuracy of each model. All three models (OSIRIS, LAZAR and Toxtree) were able to identify VOC with a potential carcinogenicity or mutagenicity risk for humans, however presenting differences concerning the specificity, sensitivity, and accuracy. The best predictive performances were found for OSIRIS and LAZAR for carcinogenicity and OSIRIS for mutagenicity, as these softwares presented a combination of negative predictive power and lower risk of false positives (high specificity) for those endpoints. The heterogeneity of results found with different softwares reinforce the importance of using a combination of in silico models to occupational toxicological risk assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Chih-chung Chang

    2008-03-01

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

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

    Science.gov (United States)

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

    2008-03-01

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

  16. [Characterization of volatile organic compounds (VOCs) emission from recycled waste polymethyl methacrylate (PMMA) industry].

    Science.gov (United States)

    Wang, Zhe-Ming; Xu, Zhi-Rong; Ye, Hong-Yu; Xu, Ming-Zhu; Wang, Xiao-Xing

    2013-12-01

    In the present study, the main source and characteristics of volatile organic compounds (VOCs) released from recycled waste polymethyl methacrylate (PMMA) in Zhejiang province was analyzed quantitatively and qualitatively. Based on those results, the internationally recognized evaluation model of health risk assessment was adopted in the preliminary assessment of the health risk of those VOCs. The results showed that methanol (MeOH) and methyl methacrylate (MMA) were the main pollutants. Emission from part of enterprises exceeded the national standards in MeOH and MMA, especially for fugitive emissions of odor concentration. Moreover, health risk value of fugitive emissions was very low and did not cause harm to human health. Additionally, to better accelerate industrial upgrading and environment pollution treatment, the emission limits of MeOH, MMA and odor concentration were suggested and the values of existing/new (fugitive emission) limitations were 45/30 (0.5) mg x m(-3), 30/25 (0.5) mg x m(-3), and 1000/800 (20), respectively.

  17. Diagnosis of air quality through observation and modeling of volatile organic compounds (VOCs) as pollution tracers

    Science.gov (United States)

    Liu, Wen-Tzu; Hsieh, Hsin-Cheng; Chen, Sheng-Po; Chang, Julius S.; Lin, Neng-Huei; Chang, Chih-Chung; Wang, Jia-Lin

    2012-08-01

    This study used selected ambient volatile organic compounds (VOCs) as pollution tracers to study the effects of meteorology on air quality. A remote coastal site was chosen as a receptor to monitor pollutants transported upwind from urban traffic and industrial sources. Large concentration variability in VOC concentrations was observed at the coastal site due to rapid changes in meteorology, which caused periodic land-sea exchange of air masses. To assure the quality of the on-line measurements, uniform concentrations of chlorofluorocarbon-113 (CFC-113) were exploited as an internal check of the instrument's stability and the resulting data quality. A VOC speciated air quality model was employed to simulate both temporal and spatial distributions of VOC plumes. The model successfully captured the general features of the variations of toluene as a pollution tracer, which suggests that emissions and meteorology were reasonably well simulated in the model. Through validation by observation, the model can display both the temporal and spatial distribution of air pollutants in a dynamic manner. Thus, a more insightful understanding of how local air quality is affected by meteorology can be obtained.

  18. Volatile organic compounds in urban rivers and their estuaries in Osaka, Japan.

    Science.gov (United States)

    Yamamoto, K; Fukushima, M; Kakutani, N; Kuroda, K

    1997-01-01

    The levels and distribution of 55 volatile organic compounds (VOCs) were determined by purge and trap GC-MS on water samples from 30 sites within the urban rivers and estuaries of Osaka, a populated industrialized city of Japan. Forty of 55 target VOCs listed in the US EPA Method 524.2 were detected. Dichloromethane (DCM) was found at higher levels at all of the sampling sites. The distribution of dominant VOCs followed four different patterns. First, the most common VOCs (DCM, toluene, trichloroethene and tetrachloroethene) showed concentration maxima in the river segments, and the sites of maximum concentration fluctuated due to irregular large spills and/or loadings. Second, one VOC (cis-1,2-dichloroethene) was evenly distributed in particular rivers due to fixed loadings. Both of these patterns were found in the upper and middle reaches. Third, some of VOCs (1,2,3-trichloropropane and benzene) were specific to a single industrial site and truceable to those sources. Finally, some VOCs showed no concentration maxima along the rivers and entered from multiple sources (chloroform and bromodichloromethane). Diurnal variations of VOCs at the border of the city area, receiving domestic and industrial discharges, provided information to interpret their observed downstream distribution and possible sources.

  19. Measurement of personal exposure to volatile organic compounds and particle associated PAH in three UK regions.

    Science.gov (United States)

    Saborit, Juana Mari Delgado; Aquilina, Noel J; Meddings, Claire; Baker, Stephen; Vardoulakis, Sotiris; Harrison, Roy M

    2009-06-15

    Personal exposures to 15 volatile organic compounds (VOC) and 16 polycyclic aromatic hydrocarbons (PAH) of 100 adult nonsmokers living in three UK areas, namely London, West Midlands, and rural South Wales, were measured using an actively pumped sampler carried around by the volunteers for 5/1 (VOC/PAH) consecutive 24-h periods, following their normal lifestyle. Results from personal exposure measurements categorized by geographical location, type of dwelling, and exposure to environmental tobacco smoke (ETS) are presented. The average personal exposure concentration to benzene, 1,3-butadiene, and benzo(a)pyrene representing the main carcinogenic components of the VOC and PAH mixture were 2.2 +/- 2.5 microg/m3, 0.4 +/- 0.7 microg/m3, and 0.3 +/- 0.7 ng/m3 respectively. The association of a number of generic factors with personal exposure concentrations was investigated, including first-line property, traffic, the presence of an integral garage, and ETS. Only living in houses with integral garages and being exposed to ETS were identified as unequivocal contributors to VOC personal exposure, while only ETS had a clear effect upon PAH personal exposures. The measurements of personal exposures were compared with health-based European and UK air quality guidelines, with some exceedences occurring. Activities contributing to high personal exposures included the use of a fireplace in the home, ETS exposure, DIY (i.e., construction and craftwork activities), and photocopying, among others.

  20. Volatile organic compound analysis in wood combustion and meat cooking emissions

    International Nuclear Information System (INIS)

    Zielinska, B.; McDonald, J.

    1999-01-01

    Residential wood combustion and meat cooking emissions were each analyzed for volatile organic compounds (VOC). Emissions were diluted 60--100 times, cooled to ambient temperature, and allowed 80 seconds for condensation prior to collection with the aid of a DRI-constructed dilution stack sampler. Fireplace and wood-stove emissions testing was conducted at the DRI facilities. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Meat emissions testing was conducted at the CE-CERT stationary emissions lab, University of California, Riverside. Meat type, fat content, and cooking appliance were changed in different tests. VOCs were collected using stainless-steel 6 L canisters and Tenax cartridges, whereas for carbonyl compound collection 2,4-dinitrophenylhydrazine (DNPH)-impregnated C 18 SepPack cartridges were used. Analysis of VOC collected with canisters and Tenax cartridges was conducted by Gas Chromatography/Mass Spectrometry (GC/MS) and by GC/FID/ECD (flame ionization detection/electron capture detection). DNPH-impregnated cartridges were analyzed for fourteen C 1 --C 7 carbonyl compounds, using the HPLC method. The results of these measurements are discussed

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

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

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

  2. River water quality analysis via headspace detection of volatile organic compounds

    Science.gov (United States)

    Tang, Johnny Jock Lee; Nishi, Phyllis Jacqueline; Chong, Gabriel Eng Wee; Wong, Martin Gideon; Chua, Hong Siang; Persaud, Krishna; Ng, Sing Muk

    2017-03-01

    Human civilization has intensified the interaction between the community and the environment. This increases the threat on the environm ent for being over exploited and contaminated with m anmade products and synthetic chemicals. Of all, clean water is one of the resources that can be easily contaminated since it is a universal solvent and of high mobility. This work reports the development and optimization of a water quality monitoring system based on metal oxide sensors. The system is intended to a ssist the detection of volatile organic compounds (VOCs) present in water sources online and onsite. The sampling mechanism was based on contactless mode, where headspace partial pressure of the VOCs formed above the water body in a close chamber was drawn for detection at the sensor platform. Pure toluene was used as standard to represent the broad spectrum of VOCs, and the sensor dynamic range was achieved from 1-1000 ppb. Several sensing parameters such as sampling time, headspace volume, and sensor recovery were s tudied and optimized. Besides direct detection of VOC contaminants in the water, the work has also been extended to detect VOCs produced by microbial communities and to c orrelate the size of the communities with the reading of V OCs recorded. This can serve to give b etter indication of water quality, not only on the conce ntration of VOCs c ontamination from chemicals, but also the content of microbes, which some can have severe effect on human health.

  3. [Occurrence and distribution of volatile organic compounds in conventional and advanced drinking water treatment processes].

    Science.gov (United States)

    Chen, Xi-Chao; Luo, Qian; Chen, Hu; Wei, Zi; Wang, Zi-Jian; Xu, Ke-Wen

    2013-12-01

    A series of experiments were conducted to study the occurrence and distribution of volatile organic compounds (VOCs) in conventional and advanced drinking water treatment processes of 3 water treatment plants in Lianyungang City. Results showed that 30 compounds of 3 classes were detected from 67 kinds of VOCs in all the samples collected. The concentrations of carbonyl compounds, halogenated hydrocarbons and benzenes detected were in the ranges of 0.04-61.27, 0.02-35.61 and 0.07-2.33 microg x L(-1) respectively. Comparing the changes of different VOCs in three drinking water treatment plants, conventional chlorination process could effectively remove benzenes but meanwhile produced trihalomethanes (THMs). Additional advanced treatment ozonation-biological activated carbon process could decrease the formation of THMs during pre-chlorination but produced new risky contaminants like carbonyl compounds. The changes of VOCs in tap water were also investigated. It was found that carbonyl compounds produced by ozonation could be further transformed to THMs with residual chlorine. However, the health risks of all detected compounds in tap water were at a low level, except that the carcinogenic risk of crotonaldehydes (9.3 x 10(-5)-2.2 x 10(-4)) was slightly higher than the US EPA threshold (10(-6)-10(-4)).

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

    Science.gov (United States)

    Chang, Chang-Tang; Chen, Bor-Yann

    2008-05-30

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

  5. Analysis of the build-up of semi and non volatile organic compounds on urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna

    2011-04-01

    Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75-300 μm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 μm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 were found to dominate SVOC and NVOC build-up on roads. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Characterization and source apportionment of volatile organic compounds in urban and suburban Tianjin, China

    Science.gov (United States)

    Han, Meng; Lu, Xueqiang; Zhao, Chunsheng; Ran, Liang; Han, Suqin

    2015-03-01

    Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds (VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin, China during the HaChi (Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected, and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area (36%) was much higher than that at the urban area (16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas.

  7. A study of volatile organic compounds evolved in urban waste disposal bins

    Science.gov (United States)

    Statheropoulos, M.; Agapiou, A.; Pallis, G.

    Volatile organic compounds (VOCs) evolved in urban waste disposal bins in different situations were studied. Waste of various loads (full, empty, partially filled bins), remained uncollected in the containers for variable time and under different weather conditions. Analysis of VOCs was carried out by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). Over 150 compounds have been identified and the 30 most abundant were quantified. Generally, VOCs were determined in the range of micrograms per cubic meter. Median concentrations of the most prominent VOCs were: decane (694.9 μg m -3), acetic acid ethyl ester (353.1 μg m -3), limonene (334.9 μg m -3), nonane (257.4 μg m -3), ethanol (216.1 μg m -3), benzene 1,2,4-trimethyl (212.6 μg m -3) and undecane (159.1 μg m -3). High levels of alkanes, alkylbenzenes and terpenes are responsible for undesirable odours. The variety and concentration of VOCs evolved depends on the prevailing conditions such as time of waste exposure, load and weather. When waste accumulates in bins under unforeseen circumstances, some compounds produced may exceed olfactory and safety thresholds representing a source of potential health impact.

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

    Science.gov (United States)

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

    2017-03-01

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

  9. Anthropogenic emissions of non-methane volatile organic compounds in China

    Science.gov (United States)

    Klimont, Zbigniew; Streets, David G.; Gupta, Shalini; Cofala, Janusz; Lixin, Fu; Ichikawa, Yoichi

    Inventories of emissions of non-methane volatile organic compounds (NMVOC) in China are reported for the years 1990, 1995, 2000, 2010, and 2020. For 1990 and 1995, historical activity data were assembled for more than 70 processes that lead to the release of NMVOC. Appropriate emission factors were developed, based on Western, Asian and Chinese experience. It is estimated that emissions were 11.1 Tg in 1990 and 13.1 Tg in 1995, principally from the combustion of biofuels and coal in small combustors. All emissions are presented at provincial level. Using appropriate growth factors derived from anticipated economic, population, and lifestyle changes, and factoring in regulatory changes and technology improvements, we estimate that emissions could grow to 15.6 Tg in 2000, 17.2 Tg in 2010, and 18.2 Tg in 2020. Though activity growth rates are much higher than these increases would imply, technology improvements mediate the increases. Emissions from solvent use, paint use, and transport become increasingly important as time goes on. The sectoral distribution and per capita level of China's emissions are compared with those of other countries. Finally, gridded NMVOC emission fields are presented at 1°×1° resolution, and speciation of the emissions into 16 chemical types is reported.

  10. Source apportionment of ambient volatile organic compounds in the Pearl River Delta, China: Part II

    Science.gov (United States)

    Liu, Ying; Shao, Min; Lu, Sihua; Chang, Chih-Chung; Wang, Jia-Lin; Fu, Linlin

    The chemical mass balance receptor model was applied to the source apportionment of 58 hydrocarbons measured at seven sites in a field campaign that examined regional air quality in the Pearl River Delta (PRD) region in the fall of 2004. A total of 12 volatile organic compound (VOC) emission sources were considered, including gasoline- and diesel-powered vehicle exhausts, headspace vapors of gasoline and diesel fuel, vehicle evaporative emissions, liquid petroleum gas (LPG) leakage, paint vapors, asphalt emissions from paved roads, biomass combustion, coal combustion, the chemical industry, and petroleum refineries. Vehicle exhaust was the largest source of VOCs, contributing to >50% of ambient VOCs at the three urban sites (Guangzhou, Foshan, and Zhongshan). LPG leakage played an important role, representing 8-16% of emissions at most sites in the PRD. Solvent usage was the biggest emitter of VOCs at Dongguan, an industrial site, contributing 33% of ambient VOCs. Similarly, at Xinken, a non-urban site, the evaporation of solvents and coatings was the largest emission source, accounting for 31% of emissions, probably because it was downwind of Dongguan. Local biomass combustion was a noticeable source of VOCs at Xinken; although its contribution was estimated at 14.3%, biomass combustion was the third largest VOC source at this site.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  12. Variation in biogenic volatile organic compound emission pattern of Fagus sylvatica L. due to aphid infection

    Science.gov (United States)

    Joó, É.; Van Langenhove, H.; Šimpraga, M.; Steppe, K.; Amelynck, C.; Schoon, N.; Müller, J.-F.; Dewulf, J.

    2010-01-01

    Volatile organic compounds (VOCs) have been the focus of interest to understand atmospheric processes and their consequences in formation of ozone or aerosol particles; therefore, VOCs contribute to climate change. In this study, biogenic VOCs (BVOCs) emitted from Fagus sylvatica L. trees were measured in a dynamic enclosure system. In total 18 compounds were identified: 11 monoterpenes (MT), an oxygenated MT, a homoterpene (C 14H 18), 3 sesquiterpenes (SQT), isoprene and methyl salicylate. The frequency distribution of the compounds was tested to determine a relation with the presence of the aphid Phyllaphis fagi L. It was found that linalool, (E)-β-ocimene, α-farnesene and a homoterpene identified as (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), were present in significantly more samples when infection was present on the trees. The observed emission spectrum from F. sylvatica L. shifted from MT to linalool, α-farnesene, (E)-β-ocimene and DMNT due to the aphid infection. Sabinene was quantitatively the most prevalent compound in both, non-infected and infected samples. In the presence of aphids α-farnesene and linalool became the second and third most important BVOC emitted. According to our investigation, the emission fingerprint is expected to be more complex than commonly presumed.

  13. Volatile organic compounds in a multi-storey shopping mall in guangzhou, South China

    Science.gov (United States)

    Tang, Jianhui; Chan, C. Y.; Wang, Xinming; Chan, L. Y.; Sheng, Guoying; Fu, Jiamo

    Volatile organic compounds (VOCs) specified in the USEPA TO-14 list were analysed in microenvironments of a multi-storey shopping mall in Guangzhou city, South China. The microenvironments studied include both indoor (department store, supermarket, fast-food court, electronic games room, children's playground, gallery and book store) and outdoor ones (rooftop and ground level entrance). The characteristics and concentration of VOCs varied widely in differing microenvironments. The average concentrations of the total VOCs in the indoor microenvironments ranged from 178.5 to 457.7 μg m -3 with a maximum of 596.8 μg m -3. The fast-food court and a leather products department store had the highest concentrations of benzene, toluene, ethylbenzene, xylenes and chlorinated hydrocarbons. A high level of 1,4-dichlorobenzene was found in all indoor microenvironments with an average of 12.3 μg m -3 and a maximum of 44.3 μg m -3. The ratios of average indoor to outdoor concentrations (I/O ratio) in all indoor microenvironments fell between 1 and 3, except an average of 24.6 and a maximum of 77.8 in the fashion department store for 1,4-dichlorobenzene. Indoor emission sources of monocyclic aromatic hydrocarbons in the shopping mall might include cooking stoves, leather products and building materials. Chlorinated hydrocarbons, however, were possibly connected with their use as cleaning agents or deodorizers.

  14. Studies on volatile organic compounds of some truffles and false truffles.

    Science.gov (United States)

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

    2014-01-01

    Results of solid phase micro-extraction coupled to gas chromatography and mass spectrometry analyses, accomplished on sporophores of 11 species of truffles and false truffles, are reported. Volatile organic compounds (VOCs) found in Gautieria morchelliformis were dimethyl sulphide, 1,3-octadiene, 3,7-dimethyl-1,6-octadien-3-ol, amorphadiene, isoledene and cis-muurola-3,5-diene. In Hymenogaster luteus var. luteus, presence of 1,3-octadiene, 1-octen-3-ol, 3-octanone, 3-octanol and 4-acetylanisole was revealed. Two VOCs, 4-acetylanisole and β-farnesene, constituted aroma of Hymenogaster olivaceus.Melanogaster broomeanus exhibited as components of its aroma 2-methyl-1,3-butadiene, 2-methylpropanal, 2-methylpropanol, isobutyl acetate, 3,7-dimethyl-1,6-octadien-3-ol, 3-octanone and β-curcumene. VOC profile of Octavianina asterosperma was characterised by the presence of dimethyl sulphide, ethyl 2-methylpropanoate, methyl 2-methylbutanoate and 3-octanone. Tuber rufum var. rufum and Pachyphloeus conglomeratus showed the presence of dimethyl sulphide only.

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

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-09-27

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

  16. Emissions of volatile organic compounds from maize residue open burning in the northern region of Thailand

    Science.gov (United States)

    Sirithian, Duanpen; Thepanondh, Sarawut; Sattler, Melanie L.; Laowagul, Wanna

    2018-03-01

    Emission factors for speciated volatile organic compounds (VOCs) from maize residue burning were determined in this study based on chamber experiments. Thirty-six VOC species were identified by Gas Chromatography/Mass Spectrometer (GC/MS). They were classified into six groups, including alkanes, alkenes, oxygenated VOCs, halogenated VOCs, aromatics and other. The emission factor for total VOCs was estimated as about 148 mg kg-1 dry mass burned. About 68.4% of the compounds were aromatics. Field samplings of maize residues were conducted to acquire the information of fuel characteristics including fuel loading, fraction of maize residues that were actually burned as well as proximate and elemental analysis of maize residues. The emission factors were then applied to estimate speciated VOC emissions from maize residue open burning at the provincial level in the upper-northern region of Thailand for the year 2014. Total burned area of maize covered an area of about 500,000 ha which was about 4.7% of the total area of upper-northern region of the country. It was found that total VOC emissions released during the burning season (January-April) was about 79.4 tons. Ethylbenzene, m,p-xylene, 1,2,4-trimethylbenzene, acetaldehyde and o-xylene were the major contributors, accounting for more than 65% of total speciated VOC emissions.

  17. Fluxes and concentrations of volatile organic compounds above central London, UK

    Directory of Open Access Journals (Sweden)

    B. Langford

    2010-01-01

    Full Text Available Concentrations and fluxes of eight volatile organic compounds (VOCs were measured during October 2006 from a high telecom tower above central London, as part of the CityFlux contribution to the REPARTEE I campaign. A continuous flow disjunct eddy covariance technique with analysis by proton transfer reaction mass spectrometry was used. Daily averaged VOC mixing ratios were within the range 1–19 ppb for the oxygenated compounds (methanol, acetaldehyde and acetone and 0.2–1.3 ppb for the aromatics (benzene, toluene and C2-benzenes. Typical VOC fluxes were in the range 0.1–1.0 mg m−2 h−1. There was a non-linear relationship between VOC fluxes and traffic density for most of the measured compounds. Traffic activity was estimated to account for approximately 70% of the aromatic compound fluxes, whereas non-traffic related sources were found to be more important for methanol and isoprene fluxes. The measured fluxes were comparable to the estimates of the UK national atmospheric emission inventory for the aromatic VOCs and CO. In contrast, fluxes of the oxygenated compounds were about three times larger than inventory estimates. For isoprene and acetonitrile this difference was many times larger. At temperatures over 25° C it is estimated that more than half the isoprene observed in central London is of biogenic origin.

  18. Modeling human exposure levels to airborne volatile organic compounds by the hebei spirit oil spill.

    Science.gov (United States)

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan; Yi, Jongheop

    2012-01-01

    The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. The extent of airborne exposure was clearly not the same as that for normal conditions.

  19. Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming.

    Science.gov (United States)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Asmund; Michelsen, Anders; Holopainen, Jarmo K; Rinnan, Riikka

    2010-07-01

    *Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects.

  20. Microbial volatile organic compounds in moldy interiors: a long-term climate chamber study.

    Science.gov (United States)

    Schuchardt, Sven; Strube, Andrea

    2013-06-01

    The present study simulated large-scale indoor mold damage in order to test the efficiency of air sampling for the detection of microbial volatile organic compounds (MVOCs). To do this, a wallpaper damaged by condensation was stored in a climate chamber (representing a hypothetical test room of 40 m(3) volume) and was inoculated with 14 typical indoor fungal strains. The chamber ventilation conditions were adjusted to common values found in moldy homes, and the mold growth was allowed to continue to higher than average values. The MVOC content of the chamber air was analyzed daily for a period of 105 days using coupled gas chromatography/mass spectrometry (GC-MS). This procedure guarantees MVOC profiling without external factors such as outdoor air, building materials, furniture, and occupants. However, only nine MVOCs could be detected during the sampling period, which indicates that the very low concentrated MVOCs are hardly accessible, even under these favorable conditions. Furthermore, most of the MVOCs that were detected cannot be considered as reliable indicators of mold growth in indoor environments. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Treatment of ground water contaminated with volatile organic compounds using second generation ultraviolet light technology

    International Nuclear Information System (INIS)

    Lyandres, S.E.; Rees, J.T.; Folsom, E.N.; Boegel, A.J.

    1991-03-01

    Pilot tests, using a second generation ultraviolet (UV) light technology, were run on ground water samples taken f rom two separate aquifers contaminated with volatile organic compounds (VOCS) at the Lawrence Livermore National Laboratory (LLNL) in Alameda County, California. The VOCs included gasoline, TCE, and 1,2-DCA. VOC concentrations in the ground water ranged from 11 to 1,000 ppB. Discharges of treated ground water at LLNL are not to exceed 5 ppb total VOCs under a Federal National Pollution Discharge Elimination System discharge permit. Test results indicated that double-bonded VOCS, including aromatic compounds and TCE, were decomposed quickly and efficiently to low or nondetectable levels (<0.5 ppB, analyzed with a gas chromatograph). An equivalent level of degradation for 1,2-DCA required a moderately higher UV energy input and greater concentrations of additives. Concentrations of peroxide tested ranged between 10 and 60 ppM; however, those above 30 ppM did not significantly increase the rate of VOC destruction

  2. Leaf enclosure measurement for determining marijuana volatile organic compound emission factors

    Science.gov (United States)

    Wang, C. T.; Vizuete, W.; Wiedinmyer, C.; Ashworth, K.; Harley, P. C.; Ortega, J. V.

    2017-12-01

    In 2014, Colorado became the first US state to legalize the industrial-scale cultivation of marijuana plants. There are now more than 700 marijuana cultivation facilities (MCFs) in operation in the greater Denver area. High concentrations of biogenic volatile organic compounds (VOCs), predominantly monoterpenes (C10H16) such as alpha-pinene, myrcene, and limonene have been observed in the grow rooms of MCFs, suggesting MCFs have the potential to release a significant amount of reactive VOCs into the atmosphere. Further, many MCFs are located in the urban core, where other urban emission sources are concentrated, resulting in interactions which can lead to the formation of ozone, impacting air quality. The little research done on marijuana has focused on indoor air quality and occupational exposure, or identification of the compounds associated with the characteristic smells of marijuana plants. We know of no previous studies that have identified or quantified the monoterpene emission rates from marijuana. Here, we collected air samples from leaf enclosures from different marijuana clones at different growth stages onto sorbent cartridges. These samples were analyzed using GC-MS/-FID to identify and quantify the VOCs emitted by growing marijuana plants. These results were then used to estimate basal emission rates at standard conditions (T=30 C, PPFD = 1000 umol/m2/s) using standard algorithms. We discuss the potential impact on air quality from these VOCs emitted into the atmosphere using air quality models.

  3. Compositions of volatile organic compounds emitted from melted virgin and waste plastic pellets.

    Science.gov (United States)

    Yamashita, Kyoko; Yamamoto, Naomichi; Mizukoshi, Atsushi; Noguchi, Miyuki; Ni, Yueyong; Yanagisawa, Yukio

    2009-03-01

    To characterize potential air pollution issues related to recycling facilities of waste plastics, volatile organic compounds (VOCs) emitted from melted virgin and waste plastics pellets were analyzed. In this study, laboratory experiments were performed to melt virgin and waste plastic pellets under various temperatures (150, 200, and 250 degrees C) and atmospheres (air and nitrogen [N2]). In the study presented here, low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS) and the recycled waste plastic pellets were used. The VOCs generated from each plastic pellets were collected by Tenax/Carboxen adsorbent tubes and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). The result showed the higher temperatures generated larger amounts of total VOCs (TVOCs). The VOCs emitted from the virgin plastic pellets likely originated from polymer degradation. Smaller TVOC emissions were observed in N2 atmosphere than in air atmosphere. In particular, larger amounts of the oxygenated compounds, which are generally hazardous and malodorous, were detected in air than in N2. In addition to the compounds originating from polymer degradation, the compounds originating from the plastic additives were also detected from LDPE and PS. Furthermore, various species of VOCs likely originating from contaminant inseparate polyvinyl chloride (PVC), food residues, cleaning agents, degreasers, and so on were detected from the waste plastic. Thus, melting waste plastics, as is conducted in recycling facilities, might generate larger amounts of potentially toxic compounds than producing virgin plastics.

  4. Volatile Organic Compound Emissions from Dairy Farming and their effect on San Joaquin Valley Air Quality

    Science.gov (United States)

    Blake, D. R.; Yang, M.; Meinardi, S.; Krauter, C.; Rowland, F. S.

    2009-05-01

    The San Joaquin Valley Air Pollution Control District of California issued a report identifying dairies as a main source of Volatile Organic Compounds (VOCs). A dairy study funded by the California Air Resources Board commenced shortly after the report was issued. Our University of California Irvine group teamed with California State University Fresno to determine the major sources of VOCs from various dairy operations and from a variety of dairy types. This study identified ethanol and methanol as two gases produced in major quantities throughout the dairies in the San Joaquin valley as by-products of yeast fermentation of silage. Three different types of sampling protocols were employed in order to determine the degree of enhancement of the target oxygenates in the valley air shed. Their sources, emission profiles, and emission rates were determined from whole air samples collected at various locations at the six dairies studied. An assessment of the impact of dairy emissions in the valley was achieved by using data obtained on low altitude NASA DC-8 flights through the valley, and from ground level samples collected though out the valley in a grid like design. Our data suggest that a significant amount of O3 production in the valley may come from methanol, ethanol, and acetaldehyde (a photochemical by-product ethanol oxidation). Our findings indicate that improvement to valley air quality may be obtained by focusing on instituting new silage containment practices and regulations.

  5. Improving the Sustainability of Office Partition Manufacturing: Balancing Options for Reducing Emissions of Volatile Organic Compounds

    Directory of Open Access Journals (Sweden)

    Marc A. Rosen

    2009-06-01

    Full Text Available Options are examined to improve the sustainability of office partition manufacturing by reducing volatile organic compounds (VOC emissions. Base VOC emissions for a typical plant are estimated using a mass balance approach. Pollution prevention and sustainability measures are assessed using realistic criteria and weightings. Sustainability has been considered from an industry perspective, considering factors like economics, environmental impact, quality, health and safety. Through a case study, it is demonstrated that several advantageous options are available for reducing VOC emissions in manufacturing office furniture partitions, and thereby enhancing the sustainability of that industrial operation. The measures deemed most viable include implementing several best management practices, not painting of non-visible parts, switching gluing processes, recycling solvent and modifying attachments. The results are intended to be balanced so as to improve their acceptability and adoptability by industry. It appears that it would be advantageous for manufacturers of office panels to evaluate the feasibility of these measures and to implement the most appropriate. The results are likely extendable to other operations in the wood furniture industry, and would improve their sustainability.

  6. Feature extraction techniques using multivariate analysis for identification of lung cancer volatile organic compounds

    Science.gov (United States)

    Thriumani, Reena; Zakaria, Ammar; Hashim, Yumi Zuhanis Has-Yun; Helmy, Khaled Mohamed; Omar, Mohammad Iqbal; Jeffree, Amanina; Adom, Abdul Hamid; Shakaff, Ali Yeon Md; Kamarudin, Latifah Munirah

    2017-03-01

    In this experiment, three different cell cultures (A549, WI38VA13 and MCF7) and blank medium (without cells) as a control were used. The electronic nose (E-Nose) was used to sniff the headspace of cultured cells and the data were recorded. After data pre-processing, two different features were extracted by taking into consideration of both steady state and the transient information. The extracted data are then being processed by multivariate analysis, Linear Discriminant Analysis (LDA) to provide visualization of the clustering vector information in multi-sensor space. The Probabilistic Neural Network (PNN) classifier was used to test the performance of the E-Nose on determining the volatile organic compounds (VOCs) of lung cancer cell line. The LDA data projection was able to differentiate between the lung cancer cell samples and other samples (breast cancer, normal cell and blank medium) effectively. The features extracted from the steady state response reached 100% of classification rate while the transient response with the aid of LDA dimension reduction methods produced 100% classification performance using PNN classifier with a spread value of 0.1. The results also show that E-Nose application is a promising technique to be applied to real patients in further work and the aid of Multivariate Analysis; it is able to be the alternative to the current lung cancer diagnostic methods.

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

    Science.gov (United States)

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

    2017-01-21

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

  8. Predictors of blood volatile organic compound levels in Gulf coast residents.

    Science.gov (United States)

    Werder, Emily J; Gam, Kaitlyn B; Engel, Lawrence S; Kwok, Richard K; Ekenga, Christine C; Curry, Matthew D; Chambers, David M; Blair, Aaron; Miller, Aubrey K; Birnbaum, Linda S; Sandler, Dale P

    2017-12-29

    To address concerns among Gulf Coast residents about ongoing exposures to volatile organic compounds, including benzene, toluene, ethylbenzene, o-xylene, and m-xylene/p-xylene (BTEX), we characterized current blood levels and identified predictors of BTEX among Gulf state residents. We collected questionnaire data on recent exposures and measured blood BTEX levels in a convenience sample of 718 Gulf residents. Because BTEX is rapidly cleared from the body, blood levels represent recent exposures in the past 24 h. We compared participants' levels of blood BTEX to a nationally representative sample. Among nonsmokers we assessed predictors of blood BTEX levels using linear regression, and predicted the risk of elevated BTEX levels using modified Poisson regression. Blood BTEX levels in Gulf residents were similar to national levels. Among nonsmokers, sex and reporting recent smoky/chemical odors predicted blood BTEX. The change in log benzene was -0.26 (95% CI: -0.47, -0.04) and 0.72 (0.02, 1.42) for women and those who reported odors, respectively. Season, time spent away from home, and self-reported residential proximity to Superfund sites (within a half mile) were statistically associated with benzene only, however mean concentration was nearly an order of magnitude below that of cigarette smokers. Among these Gulf residents, smoking was the primary contributor to blood BTEX levels, but other factors were also relevant.

  9. Adsorption Thermodynamic Analysis of a Quartz Tuning Fork Based Sensor for Volatile Organic Compounds Detection.

    Science.gov (United States)

    Deng, Yue; Liu, Nai-Yuan; Tsow, Francis; Xian, Xiaojun; Forzani, Erica S

    2017-11-22

    A volatile organic compounds (VOC) sensor based on molecularly imprinted polymer (MIP) modified quartz tuning fork (QTF) has been developed. In this paper, the stability of the modified sensor as a function of the MIP composition, and the temperature effect of the analyte adsorption on the sensing transduction mechanism are evaluated. By mixing MIP and PS together, the stability was improved. A target analyte, o-xylene, was chosen as the VOC model to study the sensor response in a temperature range of 6-40 °C. Langmuir model fitted adsorption isotherms were used for thermodynamic analysis. The changes in the sensitivity of the QTF sensor to temperature rendered different behaviors. For a freshly modified QTF sensor, the adsorption response increased with increasing temperature, while for an aged QTF sensor, the adsorption response decreased with increasing temperature. The results indicated that the enthalpy change of the MIP and PS composition sensing material changes from positive to negative over the course of aging. The characterization of the reaction enabled the definition of sensor calibration conditions and stable sensor performance in field testing conditions.

  10. Detection of Volatile Organics Using a Surface Acoustic Wave Array System

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, LAWRENCE F.; BARTHOLOMEW, JOHN W.; CERNOSEK, RICHARD W.; COLBURN, CHRISTOPHER W.; CROOKS, R.M.; MARTINEZ, R.F.; OSBOURN, GORDON C.; RICCO, A.J.; STATON, ALAN W.; YELTON, WILLIAM G.

    1999-10-14

    A chemical sensing system based on arrays of surface acoustic wave (SAW) delay lines has been developed for identification and quantification of volatile organic compounds (VOCs). The individual SAW chemical sensors consist of interdigital transducers patterned on the surface of an ST-cut quartz substrate to launch and detect the acoustic waves and a thin film coating in the SAW propagation path to perturb the acoustic wave velocity and attenuation during analyte sorption. A diverse set of material coatings gives the sensor arrays a degree of chemical sensitivity and selectivity. Materials examined for sensor application include the alkanethiol-based self-assembled monolayer, plasma-processed films, custom-synthesized conventional polymers, dendrimeric polymers, molecular recognition materials, electroplated metal thin films, and porous metal oxides. All of these materials target a specific chemical fi.mctionality and the enhancement of accessible film surface area. Since no one coating provides absolute analyte specificity, the array responses are further analyzed using a visual-empirical region-of-influence (VERI) pattern recognition algorithm. The chemical sensing system consists of a seven-element SAW array with accompanying drive and control electronics, sensor signal acquisition electronics, environmental vapor sampling hardware, and a notebook computer. Based on data gathered for individual sensor responses, greater than 93%-accurate identification can be achieved for any single analyte from a group of 17 VOCs and water.

  11. Impacts of simulated herbivory on volatile organic compound emission profiles from coniferous plants

    Science.gov (United States)

    Faiola, C. L.; Jobson, B. T.; VanReken, T. M.

    2015-01-01

    The largest global source of volatile organic compounds (VOCs) in the atmosphere is from biogenic emissions. Plant stressors associated with a changing environment can alter both the quantity and composition of the compounds that are emitted. This study investigated the effects of one global change stressor, increased herbivory, on plant emissions from five different coniferous species: bristlecone pine (Pinus aristata), blue spruce (Picea pungens), western redcedar (Thuja plicata), grand fir (Abies grandis), and Douglas-fir (Pseudotsuga menziesii). Herbivory was simulated in the laboratory via exogenous application of methyl jasmonate (MeJA), a herbivory proxy. Gas-phase species were measured continuously with a gas chromatograph coupled to a mass spectrometer and flame ionization detector (GC-MS-FID). Stress responses varied between the different plant types and even between experiments using the same set of saplings. The compounds most frequently impacted by the stress treatment were alpha-pinene, beta-pinene, 1,8-cineol, beta-myrcene, terpinolene, limonene, and the cymene isomers. Individual compounds within a single experiment often exhibited a different response to the treatment from one another.

  12. Optimization and evaluation of multi-bed adsorbent tube method in collection of volatile organic compounds

    Science.gov (United States)

    Ho, Steven Sai Hang; Wang, Liqin; Chow, Judith C.; Watson, John G.; Xue, Yonggang; Huang, Yu; Qu, Linli; Li, Bowei; Dai, Wenting; Li, Lijuan; Cao, Junji

    2018-04-01

    The feasibility of using adsorbent tubes to collect volatile organic compounds (VOCs) has been demonstrated since the 1990's and standardized as Compendium Method TO-17 by the U.S. Environmental Protection Agency (U.S EPA). This paper investigates sampling and analytical variables on concentrations of 57 ozone (O3) precursors (C2-C12 aliphatic and aromatic VOCs) specified for the Photochemical Assessment Monitoring Station (PAMS). Laboratory and field tests examined multi-bed adsorbent tubes containing a sorbate combination of Tenax TA, Carbograph 1 TD, and Carboxen 1003. Analyte stabilities were influenced by both collection tube temperature and ambient O3 concentrations. Analytes degraded during storage, while blank levels were elevated by passive adsorption. Adsorbent tube storage under cold temperatures (- 10 °C) in a preservation container filled with solid silica gel and anhydrous calcium sulfate (CaSO4) ensured sample integrity. A high efficiency (> 99%) O3 scrubber (i.e., copper coil tube filled with saturated potassium iodide [KI]) removed O3 (i.e., 0.995) was achieved for individual analyte calibrations (with the exception of acetylene) for mixing ratios of 0.08-1.96 ppbv. The method detection limits (MDLs) were below 0.055 ppbv for a 3 L sample volume. Replicate analyses showed relative standard deviations (RSDs) of < 10%, with the majority of the analytes within < 5%.

  13. Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill

    Science.gov (United States)

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan

    2012-01-01

    Objectives The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions The extent of airborne exposure was clearly not the same as that for normal conditions. PMID:22468262

  14. Exhaled breath and fecal volatile organic biomarkers of chronic kidney disease.

    Science.gov (United States)

    Meinardi, Simone; Jin, Kyu-Bok; Barletta, Barbara; Blake, Donald R; Vaziri, Nosratola D

    2013-03-01

    While much is known about the effect of chronic kidney disease (CKD) on composition of body fluids little is known regarding its impact on the gases found in exhaled breath or produced by intestinal microbiome. We have recently shown significant changes in the composition of intestinal microbiome in humans and animals with CKD. This study tested the hypothesis that uremia-induced changes in cellular metabolism and intestinal microbiome may modify the volatile organic metabolites found in the exhaled breath or generated by intestinal flora. SD rats were randomized to CKD (5/6 nephrectomy) or control (sham operation) groups. Exhaled breath was collected by enclosing each animal in a glass chamber flushed with clean air, then sealed for 45 min and the trapped air collected. Feces were collected, dissolved in pure water, incubated at 37 degrees C in glass reactors for 24 h and the trapped air collected. Collected gases were analyzed by gas chromatography. Over 50 gases were detected in the exhaled breath and 36 in cultured feces. Four gases in exhaled breath and 4 generated by cultured feces were significantly different in the two groups. The exhaled breath in CKD rats showed an early rise in isoprene and a late fall in linear aldehydes. The CKD animals' cultured feces released larger amounts of dimethyldisulfide, dimethyltrisulfide, and two thioesters. CKD significantly changes the composition of exhaled breath and gaseous products of intestinal flora. Analysis of breath and bowel gases may provide useful biomarkers for detection and progression of CKD and its complications.

  15. Sensitive Determination of Volatile Organic Compounds and Aldehydes in Tattoo Inks.

    Science.gov (United States)

    Lim, Hyun-Hee; Shin, Ho-Sang

    2017-02-01

    As the popularity of body art including tattoo ink has increased, the safety associated with it has become an important interest. In this study, twenty volatile organic compounds (VOCs) and two aldehydes in tattoo inks were identified and quantified. Headspace and gas chromatography-mass spectrometry (HS GC-MS) for the VOCs and HS GC-MS based on derivatization with 2,2,2-trifluoroethylhydrazine (TFEH) for aldehydes was developed. Benzene, chloroform, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, propylbenzene, chlorobenzene, tert-butylbenzene, 1,3,5-trimethylbenzene, styrene, 1,2,4-trimethylbenzene, 2-chlorotoluene, 4-chlorotoluene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene and isopropyl alcohol were detected with the concentration range of 0.02-207,000 mg/kg in 16 different tattoo inks. Formaldehyde and acetaldehyde were detected with the concentration range of 0.4-308 mg/kg in the same samples. Our analytical results represent solvents used intentionally or non-intentionally in tattoo inks, and thus they may provide important information for national regulation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Volatile organic compounds as markers of quality changes during the storage of wild rocket.

    Science.gov (United States)

    Luca, Alexandru; Kjær, Anders; Edelenbos, Merete

    2017-10-01

    The quality of leafy green vegetables changes during storage. Leaves become yellow or disintegrate, and an off-odor may develop. In addition, small amounts of volatile organic compounds (VOCs) are released. In this study, the release of acetone, carbon disulfide, dimethyl sulfide, nitromethane, pentane, 3-methylfuran, 2-ethylfuran, and dimethyl disulfide from wild rocket with different initial qualities was monitored during 8d storage at 10°C and correlated to aerobic bacteria counts, yeast and mold counts, and degree of tissue disintegration. The release of VOCs, except for 3-methylfuran, was influenced by the initial quality of the leaves. The release of pentane and 2-ethylfuran was related to the degree of tissue disintegration, and the release of dimethyl sulfide and dimethyl disulfide was related to the total aerobic bacteria count. The results demonstrated that VOCs can be used as markers for monitoring the complex quality changes taking place in packaged fresh produce during storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Investigation of sensitivity and selectivity of ZnO thin film to volatile organic compounds

    Science.gov (United States)

    Teimoori, F.; Khojier, K.; Dehnavi, N. Z.

    2017-06-01

    This research addresses a detailed study on the sensitivity and selectivity of ZnO thin film to volatile organic compound (VOC) vapors that can be used for the development of VOC sensors. The ZnO thin film of 100 nm thickness was prepared by post-annealing of e-beam evaporated Zn thin film. The sample was structurally, morphologically, and chemically characterized by X-ray diffraction and field emission scanning electron microscopy analyses. The sensitivity, selectivity, and detection limit of the sample were tested with respect to a wide range of common VOC vapors, including acetone, formaldehyde, acetic acid, formic acid, acetylene, toluene, benzene, ethanol, methanol, and isopropanol in the temperature range of 200-400 °C. The results show that the best sensitivity and detection limit of the sample are related to acetone vapor in the studied temperature range. The ZnO thin film-based acetone sensor also shows a good reproducibility and stability at the operating temperature of 280 °C.

  18. Potential of antimicrobial volatile organic compounds to control Sclerotinia sclerotiorum in bean seeds

    Directory of Open Access Journals (Sweden)

    Maurício Batista Fialho

    2011-02-01

    Full Text Available The objective of this work was to evaluate the potential of an artificial mixture of volatile organic compounds (VOCs, produced by Saccharomyces cerevisiae, to control Sclerotinia sclerotiorum in vitro and in bean seeds. The phytopathogenic fungus was exposed, in polystyrene plates, to an artificial atmosphere containing a mixture of six VOCs formed by alcohols (ethanol, 3-methyl-1-butanol, 2-methyl-1-butanol and phenylethyl alcohol and esters (ethyl acetate and ethyl octanoate, in the proportions found in the atmosphere naturally produced by yeast. Bean seeds artificially contamined with the pathogen were fumigated with the mixture of VOCs in sealed glass flasks for four and seven days. In the in vitro assays, the compounds 2-methyl-1-butanol and 3-methyl-1-butanol were the most active against S. sclerotiorum, completely inhibiting its mycelial growth at 0.8 µL mL-1, followed by the ethyl acetate, at 1.2 µL mL-1. Bean seeds fumigated with the VOCs at 3.5 µL mL-1 showed a 75% reduction in S. sclerotiorum incidence after four days of fumigation. The VOCs produced by S. cerevisiae have potential to control the pathogen in stored seeds.

  19. Spatio-temporal variation of biogenic volatile organic compounds emissions in China.

    Science.gov (United States)

    Li, L Y; Chen, Y; Xie, S D

    2013-11-01

    Aiming to reduce the large uncertainties of biogenic volatile organic compounds (BVOCs) emissions estimation, the emission inventory of BVOCs in China at a high spatial and temporal resolution of 36 km × 36 km and 1 h was established using MEGANv2.1 with MM5 providing high-resolution meteorological data, based on the most detailed and latest vegetation investigations. BVOC emissions from 82 plant functional types in China were computed firstly. More local species-specific emission rates were developed combining statistical analysis and category classification, and the leaf biomass was estimated based on vegetation volume and production with biomass-apportion models. The total annual BVOC emissions in 2003 were 42.5 Tg, including isoprene 23.4 Tg, monoterpene 5.6 Tg, sesquiterpene 1.0 Tg, and other VOCs (OVOCs) 12.5 Tg. Subtropical and tropical evergreen and deciduous broadleaf shrubs, Quercus, and bamboo contributed more than 45% to the total BVOC emissions. The highest biogenic emissions were found over northeastern, southeastern, and southwestern China. Strong seasonal pattern was observed with the highest BVOC emissions in July and the lowest in January and December, with daily emission peaked at approximately 13:00 or 14:00 local time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Off-season biogenic volatile organic compound emissions from heath mesocosms: responses to vegetation cutting.

    Science.gov (United States)

    Rinnan, Riikka; Gierth, Diana; Bilde, Merete; Rosenørn, Thomas; Michelsen, Anders

    2013-01-01

    Biogenic volatile organic compounds (BVOCs) affect both atmospheric processes and ecological interactions. Our primary aim was to differentiate between BVOC emissions from above- and belowground plant parts and heath soil outside the growing season. The second aim was to assess emissions from herbivory, mimicked by cutting the plants. Mesocosms from a temperate Deschampsia flexuosa-dominated heath ecosystem and a subarctic mixed heath ecosystem were either left intact, the aboveground vegetation was cut, or all plant parts (including roots) were removed. For 3-5 weeks, BVOC emissions were measured in growth chambers by an enclosure method using gas chromatography-mass spectrometry. CO2 exchange, soil microbial biomass, and soil carbon and nitrogen concentrations were also analyzed. Vegetation cutting increased BVOC emissions by more than 20-fold, and the induced compounds were mainly eight-carbon compounds and sesquiterpenes. In the Deschampsia heath, the overall low BVOC emissions originated mainly from soil. In the mixed heath, root, and soil emissions were negligible. Net BVOC emissions from roots and soil of these well-drained heaths do not significantly contribute to ecosystem emissions, at least outside the growing season. If insect outbreaks become more frequent with climate change, ecosystem BVOC emissions will periodically increase due to herbivory.

  1. Estimation of biogenic volatile organic compounds emissions in subtropical island--Taiwan.

    Science.gov (United States)

    Chang, Ken-Hui; Chen, Tu-Fu; Huang, Ho-Chun

    2005-06-15

    Elevated tropospheric ozone is harmful to human health and plants. It is formed through the photochemical reactions involving volatile organic compounds (VOCs) and nitrogen oxides (NO(x)). The elevated ozone episodes occur mainly in summer months in the United States, while the high-ozone episodes frequently occur during the fall in Taiwan. The unique landscape of Taiwan produces tremendous amounts of biogenic VOCs in the mountain regions that are adjacent to concentrated urban areas. The urban areas, in turn, generate prodigious amounts of anthropogenic emissions. Biogenic VOC emissions have direct influence on tropospheric ozone formation. To explore the air quality problems in Taiwan, this study attempts to develop a biogenic VOC emission model suitable for air quality applications in Taiwan. The emission model is based on the Biogenic Emissions Inventory System Version 2 and coupled with a detailed Taiwan land use database. The 1999 total Taiwan biogenic VOC emissions were estimated at 214,000 metric tons. The emissions of isoprene, monoterpenes, and other VOCs were about 37.2%, 30.4%, and 32.4% of total biogenic VOC emissions, respectively. The annual total biogenic VOC emission per unit area was more than two times the value of that in any European country, implying that detailed emissions estimates in any size of region will benefit the global biogenic emission inventories.

  2. Trajectories towards clean technology. Example of volatile organic compound emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Belis-Bergouignan, Marie-Claude; Oltra, Vanessa; Saint Jean, Maider [IFREDE-E3i, University Montesquieu-Bordeaux IV, Avenue Leon Duguit, Pessac 33608 (France)

    2004-02-20

    This article is based on the observation that, up until now, corporate investment has been limited in clean technologies despite the will of governmental authorities to stimulate them in order to cope with the demands of sustainable development. The paper deals with the issue of the development of clean technologies and the role of regulations as clean technology promoters. It tries to apprehend the characteristics and specificity of clean technology from both an empirical and a theoretical point of view, so as to understand which are the most favourable (or inversely, the most detrimental) conditions for their development. We use case studies concerning the reduction of volatile organic compound (VOC) emissions in the chemical and metallurgical industries. These two examples highlight the problems created by the shift from a 'with-solvent paradigm' to a 'solvent-free paradigm' and the way clean technology trajectories may spread within such paradigms. We show that the problem of clean technology development primarily resides in some factors that impede technological adoption, although a strong and mixed incentives framework prevails. Such impediments are sector-specific, leading to different clean technology trajectories among sectors and indicating areas of sectoral intervention that could become the cornerstones of complementary technology policy.

  3. Graphene and poly(methyl methacrylate) composite laminates on flexible substrates for volatile organic compound detection

    Science.gov (United States)

    Rattanabut, Chanoknan; Wongwiriyapan, Winadda; Muangrat, Worawut; Bunjongpru, Win; Phonyiem, Mayuree; Song, Young Jae

    2018-04-01

    In this paper, we present a gas sensor for volatile organic compound (VOC) detection based on graphene and poly(methyl methacrylate) (GR/PMMA) composite laminates fabricated using CVD-grown graphene. Graphene was transferred to a poly(ethylene terephthalate) (PET) substrate by PMMA-supported wet transfer process without PMMA removal in order to achieve the deposition of GR/PMMA composite laminates on PET. The GR/PMMA and graphene sensors show completely different sensitivities to VOC vapors. The GR/PMMA and graphene sensors showed the highest sensitivities to dichloromethane (DCM). The response of the GR/PMMA sensor to DCM was 3 times higher than that of the graphene sensor but the GR/PMMA sensor hardly responded to acetone, chloroform, or benzene. The sensing mechanism of the graphene sensor can be based on the dielectric constant of VOCs, the size of VOC molecule, and electron hopping effects on defect graphene, while that of the GR/PMMA sensor can be explained in terms of the polymer swelling owing to the Hansen solubility parameter.

  4. The atmosphere can be a source of certain water soluble volatile organic compounds in urban streams

    Science.gov (United States)

    Kenner, Scott J.; Bender, David A.; Zogorski, John S.; ,; James F. Pankow,

    2014-01-01

    Surface water and air volatile organic compound (VOC) data from 10 U.S. Geological Survey monitoring sites were used to evaluate the potential for direct transport of VOCs from the atmosphere to urban streams. Analytical results of 87 VOC compounds were screened by evaluating the occurrence and detection levels in both water and air, and equilibrium concentrations in water (Cws) based on the measured air concentrations. Four compounds (acetone, methyl tertiary butyl ether, toluene, and m- & p-xylene) were detected in more than 20% of water samples, in more than 10% of air samples, and more than 10% of detections in air were greater than long-term method detection levels (LTMDL) in water. Benzene was detected in more than 20% of water samples and in more than 10% of air samples. Two percent of benzene detections in air were greater than one-half the LTMDL in water. Six compounds (chloroform, p-isopropyltoluene, methylene chloride, perchloroethene, 1,1,1-trichloroethane, and trichloroethene) were detected in more than 20% of water samples and in more than 10% of air samples. Five VOCs, toluene, m- & p-xylene, methyl tert-butyl ether (MTBE), acetone, and benzene were identified as having sufficiently high concentrations in the atmosphere to be a source to urban streams. MTBE, acetone, and benzene exhibited behavior that was consistent with equilibrium concentrations in the atmosphere.

  5. Volatile organic compounds in exhaled breath in a healthy population: effect of tobacco smoking.

    Science.gov (United States)

    Jareño-Esteban, José Javier; Muñoz-Lucas, M Ángeles; Carrillo-Aranda, Belén; Maldonado-Sanz, José Ángel; de Granda-Orive, Ignacio; Aguilar-Ros, Antonio; Civera-Tejuca, Concepción; Gutiérrez-Ortega, Carlos; Callol-Sánchez, Luis Miguel

    2013-11-01

    Tobacco smoke is a source of free radicals and reactive oxygen and nitrogen species, which are the main causes of oxidative stress. The analysis of volatile organic compounds (VOC) in exhaled breath is an indirect method of measuring the level of oxidative stress that occurs in the airways caused by tobacco consumption. The aim of this study was to determine whether smoking influences the production of VOC, in a clinically healthy population. Exhaled breath from 89 healthy volunteers, divided into three groups (non-smokers, ex-smokers and smokers) was analysed. Samples were collected using Bio-VOC® devices and transferred to universal desorption tubes. Chemical compounds were analysed by thermal desorption, gas chromatography and mass spectrometry. We analysed hexanal, heptanal, octanal, nonanal, nonanoic acid and propanoic acid, all identified by retention time and mass spectra referenced in the NIST 08 mass spectral library; confirmation was carried out using reference standards of the pure chemical compound. These VOC were found in very low concentrations. Only nonanal showed significant quantitative and qualitative statistical differences among the study groups. Nonanal concentration is dependent on smoking, but is independent of the amount of tobacco consumed, age and gender. Nonanal in exhaled breath is associated with tobacco consumption, current or previous. Nonanal is a sub-product of the destruction of the cell membrane, and its finding may be indicative of cell damage in smokers. This result appears in many farmers who smoke. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Lexuan Zhong

    2017-01-01

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

  7. Sorption of polar and nonpolar organic contaminants by oil-contaminated soil.

    Science.gov (United States)

    Chen, Hong; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

    2008-12-01

    Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil-water distribution coefficients (K(oil)). The resulting oil-contaminated soil-water distribution coefficients (K(d)) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (C(oil)) but sorption-reducing (competitive) effects at intermediate C(oil) (approximately 1 g kg(-1)). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in K(d) at C(oil) above approximately 1 g kg(-1) were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants.

  8. Biological relevance of volatile organic compounds emitted during the pathogenic interactions between apple plants and Erwinia amylovora.

    Science.gov (United States)

    Cellini, Antonio; Buriani, Giampaolo; Rocchi, Lorenzo; Rondelli, Elena; Savioli, Stefano; Rodriguez Estrada, Maria T; Cristescu, Simona M; Costa, Guglielmo; Spinelli, Francesco

    2018-01-01

    Volatile organic compounds emitted during the infection of apple (Malus pumila var. domestica) plants by Erwinia amylovora or Pseudomonas syringae pv. syringae were studied by gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry, and used to treat uninfected plants. Infected plants showed a disease-specific emission of volatile organic compounds, including several bio-active compounds, such as hexenal isomers and 2,3-butanediol. Leaf growth promotion and a higher resistance to the pathogen, expressed as a lower bacterial growth and migration in plant tissues, were detected in plants exposed to volatile compounds from E. amylovora-infected plants. Transcriptional analysis revealed the activation of salicylic acid synthesis and signal transduction in healthy plants exposed to volatiles produced by E. amylovora-infected neighbour plants. In contrast, in the same plants, salicylic acid-dependent responses were repressed after infection, whereas oxylipin metabolism was activated. These results clarify some metabolic and ecological aspects of the pathogenic adaptation of E. amylovora to its host. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  9. Separation of polar compounds using a flexible metal-organic framework

    NARCIS (Netherlands)

    Motkuri, R.K.; Thallapally, P.K.; Annapureddy, H.V.R.; Dang, L.X.; Krishna, R.; Nune, S.K.; Fernandez, C.A.; Liu, J.; McGrail, B.P.

    2015-01-01

    A flexible metal-organic framework constructed from a flexible linker is shown to possess the capability of separating mixtures of polar compounds (propanol isomers) by exploiting the differences in the saturation capacities of the constituents. Transient breakthrough simulations show that these

  10. Exploratory Research - Using Volatile Organic Compounds to Separate Heterotrophic and Autotrophic Forest Soil Respiration

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Scott D [Mississippi State Univ., Mississippi State, MS (United States)

    2015-02-09

    The initial focus of this project was to develop a method to partition soil respiration into its components (autotrophic, heterotrophic etc.) using the fingerprint of volatile organic compounds (VOCs) from soils. We were able to identify 63 different VOCs in our study; however, due to technical difficulties we were unable to take reliable measurements in order to test our hypotheses and develop this method. In the end, we changed the objectives of the project. Our new objectives were to characterize the effects of species and soil moisture regime on the composition of soil organic matter. We utilized the soils from the greenhouse experiment we had established for the soil VOC study and determined the lignin biomarker profiles of each of the treatments. We found that moisture had a significant effect on the carbon content of the soils with the low moisture treatments having higher carbon content than the high moisture treatments. We found that the relative yield of syringyl phenols (SP), ligin (Lig), and substituted fatty acids (SFA) were elevated in deciduous planted pots and reduced in conifer planted pots relative to plant-free treatments. Our results suggest nuttall oak preserved lignin and SFA, while loblolly pine lost lignin and SFA similarly to the plant free treatments. Since we did not find that the carbon concentrations of the soils were different between the species, nuttall oak probably replaced more native soil carbon than loblolly pine. This suggests that relative to loblolly pine, nuttall oak is a priming species. Since priming may impact soil carbon pools more than temperature or moisture, determining which species are priming species may facilitate an understanding of the interaction that land use and climate change may have on soil carbon pools.

  11. Volatile-organic molecular characterization of shale-oil produced water from the Permian Basin

    Science.gov (United States)

    Khan, Naima A.; Engle, Mark A.; Dungan, Barry; Holguin, F. Omar; Xu, Pei; Carroll, Kenneth C.

    2016-01-01

    Growth in unconventional oil and gas has spurred concerns on environmental impact and interest in beneficial uses of produced water (PW), especially in arid regions such as the Permian Basin, the largest U.S. tight-oil producer. To evaluate environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of PW. Although hydraulic fracturing has caused a significant increase in shale-oil production, there are no high-resolution organic composition data for the shale-oil PW from the Permian Basin or other shale-oil plays (Eagle Ford, Bakken, etc.). PW was collected from shale-oil wells in the Midland sub-basin of the Permian Basin. Molecular characterization was conducted using high-resolution solid phase micro extraction gas chromatography time-of-flight mass spectrometry. Approximately 1400 compounds were identified, and 327 compounds had a >70% library match. PW contained alkane, cyclohexane, cyclopentane, BTEX (benzene, toluene, ethylbenzene, and xylene), alkyl benzenes, propyl-benzene, and naphthalene. PW also contained heteroatomic compounds containing nitrogen, oxygen, and sulfur. 3D van Krevelen and double bond equivalence versus carbon number analyses were used to evaluate molecular variability. Source composition, as well as solubility, controlled the distribution of volatile compounds found in shale-oil PW. The salinity also increased with depth, ranging from 105 to 162 g/L total dissolved solids. These data fill a gap for shale-oil PW composition, the associated petroleomics plots provide a fingerprinting framework, and the results for the Permian shale-oil PW suggest that partial treatment of suspended solids and organics would support some beneficial uses such as onsite reuse and bio-energy production.

  12. Volatile organic compound mixing ratios above Beijing in November and December 2016

    Science.gov (United States)

    Acton, William; Shaw, Marvin; Huang, Zhonghui; Wang, Zhaoyi; Wang, Xinming; Zhang, Yanli; Davison, Brian; Langford, Ben; Mullinger, Neil; Nemitz, Eiko; Fu, Pingqing; Squires, Freya; Carpenter, Lucy; Lewis, Alastair; Hewitt, Nick

    2017-04-01

    Volatile organic compounds (VOCs) are emitted into the atmosphere from vegetation and anthropogenic sources such as fossil fuel combustion, biomass burning and the evaporation of petroleum products. These compounds play an important role in the chemistry of the lower atmosphere through secondary organic aerosol (SOA) formation and facilitating the formation of tropospheric ozone. As well as their indirect impact on human health via the formation of ozone and SOA, some VOCs, including benzene, directly affect human health adversely. Here we report VOC mixing ratios measured in Beijing during a 5 week intensive field campaign from the 7th November to the 10th December 2016. This work was carried out as part of the Sources and Emissions of Air Pollutants in Beijing (AIRPOLL-Beijing) work project within the Air Pollution and Human Health in a Developing Megacity (APHH-Beijing) research programme. APHH is a large multi-institutional study which aims to record the concentrations and identify the sources of urban air pollutants in Beijing, determine exposure, understand their effects on human health, and to identify solutions. VOC mixing ratios were recorded using a Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-ToF-MS, Ionicon Analytik) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS, SYFT Technologies). During the measurement period Beijing was subject to multiple pollution events that alternated with periods of relatively good air quality, allowing the VOCs within the polluted air masses to be identified and quantified. VOCs were sampled at 102 m with additional gradient measurements made at 3, 15, 32 and 64 m providing a vertical profile of VOC mixing ratios. Mixing ratios of methanol, acetonitrile, acetaldehyde, acetone, isoprene and aromatics species will be reported together with a discussion of potential sources. Comparisons will then be drawn with other large cities.

  13. Tethered balloon measurements of biogenic volatile organic compounds at a Boreal forest site

    Directory of Open Access Journals (Sweden)

    C. Spirig

    2004-01-01

    Full Text Available Measurements of biogenic volatile organic compounds (VOCs were performed at Hyytiälä, a Boreal forest site in Southern Finland as part of the OSOA (origin and formation of secondary organic aerosol project in August 2001. At this site, frequent formation of new particles has been observed and the role of biogenic VOCs in this process is still unclear. Tethered balloons served as platforms to collect VOC samples within the planetary boundary layer at heights up to 1.2 km above ground during daytime. Mean mixed layer concentrations of total monoterpenes varied between 10 and 170 pptv, with a-pinene, limonene and D3-carene as major compounds, isoprene was detected at levels of 2-35 pptv. A mixed layer gradient technique and a budget approach are applied to derive surface fluxes representative for areas of tens to hundreds of square kilometres. Effects of spatial heterogeneity in surface emissions are examined with a footprint analysis. Depending on the source area considered, mean afternoon emissions of the sum of terpenes range between 180 and 300 mg m-2 h-1 for the period of 2-12 August 2001. Surface fluxes close to Hyytiälä were higher than the regional average, and agree well with mean emissions predicted by a biogenic VOC emission model. Total rates of monoterpene oxidation were calculated with a photochemical model. The rates did not correlate with the occurrence of new particle formation, but the ozone pathway was of more importance on days with particle formation. Condensable vapour production from the oxidation of monoterpenes throughout the mixed layer can only account for a fraction of the increase in aerosol mass observed at the surface.

  14. Volatile-organic molecular characterization of shale-oil produced water from the Permian Basin.

    Science.gov (United States)

    Khan, Naima A; Engle, Mark; Dungan, Barry; Holguin, F Omar; Xu, Pei; Carroll, Kenneth C

    2016-04-01

    Growth in unconventional oil and gas has spurred concerns on environmental impact and interest in beneficial uses of produced water (PW), especially in arid regions such as the Permian Basin, the largest U.S. tight-oil producer. To evaluate environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of PW. Although hydraulic fracturing has caused a significant increase in shale-oil production, there are no high-resolution organic composition data for the shale-oil PW from the Permian Basin or other shale-oil plays (Eagle Ford, Bakken, etc.). PW was collected from shale-oil wells in the Midland sub-basin of the Permian Basin. Molecular characterization was conducted using high-resolution solid phase micro extraction gas chromatography time-of-flight mass spectrometry. Approximately 1400 compounds were identified, and 327 compounds had a >70% library match. PW contained alkane, cyclohexane, cyclopentane, BTEX (benzene, toluene, ethylbenzene, and xylene), alkyl benzenes, propyl-benzene, and naphthalene. PW also contained heteroatomic compounds containing nitrogen, oxygen, and sulfur. 3D van Krevelen and double bond equivalence versus carbon number analyses were used to evaluate molecular variability. Source composition, as well as solubility, controlled the distribution of volatile compounds found in shale-oil PW. The salinity also increased with depth, ranging from 105 to 162 g/L total dissolved solids. These data fill a gap for shale-oil PW composition, the associated petroleomics plots provide a fingerprinting framework, and the results for the Permian shale-oil PW suggest that partial treatment of suspended solids and organics would support some beneficial uses such as onsite reuse and bio-energy production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. A field comparison of volatile organic compound measurements using passive organic vapor monitors and stainless steel canisters.

    Science.gov (United States)

    Pratt, Gregory C; Bock, Don; Stock, Thomas H; Morandi, Maria; Adgate, John L; Ramachandran, Gurumurthy; Mongin, Steven J; Sexton, Ken

    2005-05-01

    Concurrent field measurements of 10 volatile organic compounds (VOCs) were made using passive diffusion-based organic vapor monitors (OVMs) and the U.S. Federal Reference Method, which comprises active monitoring with stainless steel canisters (CANs). Measurements were obtained throughout a range of weather conditions, repeatedly over the course of three seasons, and at three different locations in the Minneapolis/St. Paul metropolitan area. Ambient concentrations of most VOCs as measured by both methods were low compared to those of other large metropolitan areas. For some VOCs a considerable fraction of measurements was below the detection limit of one or both methods. The observed differences between the two methods were similar across measurement sites, seasons, and meteorological variables. A Bayesian analysis with uniform priors on the differences was applied, with accommodation of sometimes heavy censoring (nondetection) in either device. The resulting estimates of bias and standard deviation of the OVM relative to the CAN were computed by tert