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Sample records for acidic trace gases

  1. Adsorption and dissociation of acidic trace gases on ice surfaces - caught in the act with core level spectroscopy

    NASA Astrophysics Data System (ADS)

    Waldner, Astrid; Orlando, Fabrizio; Ammann, Markus; Kleibert, Armin; Huthwelker, Thomas; Peter, Thomas; Bartels-Rausch, Thorsten

    2015-04-01

    Chemistry and physical processes in Earth's ice and snow cover can change the composition of the atmosphere and the contaminant content of the cryosphere. They have thus direct impacts on geochemical cycles and the climate system. Our ability to predict the fate of chemicals in snow or air masses in exchange with the cryosphere on a regional scale or to model those in snow chemistry models is currently hampered by our limited understanding of the underlying mechanisms on a molecular level. So far, direct experimental observations under environmentally relevant conditions of the ice surface and of the adsorption of trace gases to it are very limited. The unique approach of this study is to combine two surface sensitive spectroscopic methods to directly probe the hydrogen-bonding network at the ice surface ( ~1 nm depth) and the concentration, depth profile (~1 to 10 nm), and dissociation degree of the dopant. We present first core-electron photoemission (XPS) and partial electron yield X-ray absorption (NEXAFS) measurements of formic acid adsorbed to ice at 240 K. The analysis of oxygen NEXAFS spectra reveals information on changes in the hydrogen-bonding network of the ice surface upon adsorption of formic acid. Depth profiles based on XPS measurements indicate that the adsorbed acid stays at the ice surface. Furthermore we obtained a preliminary estimation of the degree of formic acid dissociation at the ice surface. Results are compared to earlier core-electron studies of several trace gases adsorbed to ice at 240 K and compared to results from more traditional method to and snow to reveal fundamental aspects of the ice surface and how it interacts with dopants. Even with the focus on adsorption of acidic trace gases to ice, results of this study will thus be of high relevance also for other chemical processes in ice and snow. This is of interest not only in environmental science but also in material science, cryobiology, and astrophysics.

  2. Tropospheric trace gases

    NASA Technical Reports Server (NTRS)

    Gammon, R.; Wofsy, S. C.; Cicerone, R. J.; Delany, A. C.; Harriss, R. T.; Khalil, M. A. K.; Logan, J. A.; Midgley, P.; Prather, M.

    1985-01-01

    Trace gas concentrations in the atmosphere reflect in part the overall metabolism of the biosphere, and in part the broad range of human activities such as agriculture, production of industrial chemicals, and combustion of fossil fuels and biomass. There is compelling evidence that the composition of the atmosphere is now changing. Observed trends in trace gas levels are reviewed and implications for the chemistry of the atmosphere are discussed. Throughout the discussion, particular emphasis is given to those species which are now increasing in the atmosphere.

  3. Laboratory studies of interaction between trace gases and sulphuric acid or sulphate aerosols using flow-tube reactors

    NASA Astrophysics Data System (ADS)

    Leu, Ming-Taun

    Stratospheric ozone provides a protective shield for humanity and the global biosphere from harmful ultraviolet solar radiation. In past decades, theoretical models for the calculation of ozone balance frequently used gas-phase reactions alone in their studies. Since the discovery of the Antarctic ozone hole in 1985, however, it has been demonstrated that knowledge of heterogeneous reactions is needed to understand this significant natural event owing to the anthropogenic emission of chlorofluorocarbons. In this review I will briefly discuss the experimental techniques for the research of heterogeneous chemistry carried out in our laboratory. These experimental instruments include flow-tube reactors, an electron-impact ionization mass spectrometer, a chemical ionization mass spectrometer and a scanning mobility particle spectrometer. Numerous measurements of uptake coefficient (or reaction probability) and solubility of trace gases in liquid sulphuric acid have been performed under the ambient conditions in the upper troposphere and lower stratosphere, mainly 190-250 K and 40-80 wt% of H

  4. Greenhouse Trace Gases in Deadwood

    NASA Astrophysics Data System (ADS)

    Covey, Kristofer; Bueno de Mesquita, Cliff; Oberle, Brad; Maynard, Dan; Bettigole, Charles; Crowther, Thomas; Duguid, Marlyse; Steven, Blaire; Zanne, Amy; Lapin, Marc; Ashton, Mark; Oliver, Chad; Lee, Xuhui; Bradford, Mark

    2016-04-01

    Deadwood, long recognized as playing an important role in carbon cycling in forest ecosystems, is more recently drawing attention for its potential role in the cycling of other greenhouse trace gases. We report data from four independent studies measuring internal gas concentrations in deadwood in in three Quercus dominated upland forest systems in the Northeastern and Central United States. Mean methane concentrations in deadwood were 23 times atmospheric levels, indicating a lower bound, mean radial wood surface area flux of ~6 x 10-4 μmol CH4 m-2 s-1. Site, decay class, diameter, and species were all highly significant predictors of methane abundance in deadwood, and log diameter and decay stage interacted as important controls limiting methane concentrations in the smallest and most decayed logs. Nitrous oxide concentrations were negatively correlated with methane and on average ~25% lower than ambient, indicating net consumption of nitrous oxide. These data suggest nonstructural carbohydrates fuel archaeal methanogens and confirm the potential for widespread in situ methanogenesis in both living and deadwood. Applying this understanding to estimate methane emissions from microbial activity in living trees implies a potential global flux of 65.6±12.0 Tg CH4 yr-1, more than 20 times greater than currently considered.

  5. Emissions of formaldehyde, acetic acid, methanol, and other trace gases from biomass fires in North Carolina measured by airborne Fourier transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Yokelson, R. J.; Goode, J. G.; Ward, D. E.; Susott, R. A.; Babbitt, R. E.; Wade, D. D.; Bertschi, I.; Griffith, D. W. T.; Hao, W. M.

    1999-12-01

    Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a "flow-through" multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFTIR spectra acquired within a few kilometers of the fires yielded excess mixing ratios for 10 of the most common trace gases in the smoke: water, carbon dioxide, carbon monoxide, methane, formaldehyde, acetic acid, formic acid, methanol, ethylene, and ammonia. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were each 2.5±1%. This is in excellent agreement with (and confirms the relevance of) our results from laboratory fires. However, these ratios are significantly higher than the emission ratios reported for these compounds in some previous studies of "fresh" smoke. We present a simple photochemical model calculation that suggests that oxygenated organic compounds should be included in the assessment of ozone formation in smoke plumes. Our measured emission factors indicate that biomass fires could account for a significant portion of the oxygenated organic compounds and HOx present in the tropical troposphere during the dry season. Our fire measurements, along with recent measurements of oxygenated biogenic emissions and oxygenated organic compounds in the free troposphere, indicate that these rarely measured compounds play a major, but poorly understood, role in the HOx, NOx, and O3 chemistry of the troposphere.

  6. Measurement of Selected Organic Trace Gases During TRACE-P

    NASA Technical Reports Server (NTRS)

    Atlas, Elliot

    2004-01-01

    Major goals of the TRACE-P mission were: 1) to investigate the chemical composition of radiatively important gases, aerosols, and their precursors in the Asian outflow over the western Pacific, and 2) to describe and understand the chemical evolution of the Asian outflow as it is transported and mixed into the global troposphere. The research performed as part of this proposal addressed these major goals with a study of the organic chemical composition of gases in the TRACE-P region. This work was a close collaboration with the Blake/Rowland research group at UC-Irvine, and they have provided a separate report for their funded effort.

  7. Climate change and trace gases.

    PubMed

    Hansen, James; Sato, Makiko; Kharecha, Pushker; Russell, Gary; Lea, David W; Siddall, Mark

    2007-07-15

    Palaeoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the 'albedo flip' property of ice/water, provides a powerful trigger mechanism. A climate forcing that 'flips' the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Inertia of ice sheet and ocean provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. Carbon dioxide (CO2) is the largest human-made climate forcing, but other trace constituents are also important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. The most important of the non-CO2 forcings is methane (CH4), as it causes the second largest human-made GHG climate forcing and is the principal cause of increased tropospheric ozone (O3), which is the third largest GHG forcing. Nitrous oxide (N2O) should also be a focus of climate mitigation efforts. Black carbon ('black soot') has a high global warming potential (approx. 2000, 500 and 200 for 20, 100 and 500 years, respectively) and deserves greater attention. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could preserve Arctic ice, while also having major benefits for human health, agricultural productivity and the global environment.

  8. Method for detecting trace impurities in gases

    DOEpatents

    Freund, Samuel M.; Maier, II, William B.; Holland, Redus F.; Beattie, Willard H.

    1981-01-01

    A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (.about.2 ppm) present in commercial Xe and ppm levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

  9. Method for detecting trace impurities in gases

    DOEpatents

    Freund, S.M.; Maier, W.B. II; Holland, R.F.; Beattie, W.H.

    A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (approx. 2 ppM) present in commercial Xe and ppM levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

  10. EVALUATION OF SIGNIFICANT ANTHROPOGENIC SOURCES OF RADIATIVELY IMPORTANT TRACE GASES

    EPA Science Inventory

    The report is an initial evaluation of significant anthropogenic sources of radiatively important trace gases. missions of greenhouse gases from human activities--including fossil fuel combustion, industrial/agricultural activities, and transportation--contribute to the increasin...

  11. Trace Gases, CO2, Climate, and the Greenhouse Effect.

    ERIC Educational Resources Information Center

    Aubrecht, Gordon J., II

    1988-01-01

    Reports carbon dioxide and other trace gases can be the cause of the Greenhouse Effect. Discusses some effects of the temperature change and suggests some solutions. Included are several diagrams, graphs, and a table. (YP)

  12. Greenhouse effect of trace gases, 1970-1980

    NASA Technical Reports Server (NTRS)

    Lacis, A.; Hansen, J.; Lee, P.; Lebedeff, S.; Mitchell, T.

    1981-01-01

    Increased abundances were measured for several trace atmospheric gases in the decade 1970-1980. The equilibrium greenhouse warming for the measured increments of CH4, chlorofluorocarbons and N2O is between 50% and 100% of the equilibrium warming for the measured increase of atmospheric CO2 during the same 10 years. The combined warming of CO2 and trace gases should exceed natural global temperature variability in the 1980's and cause the global mean temperature to rise above the maximum of the late 1930's.

  13. Analysis of atmospheric spectra for trace gases

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Seals, Robert K., Jr.; Smith, Mary Ann H.; Goldman, Aaron; Murcray, David G.; Murcray, Frank J.

    1990-01-01

    The objective is the comprehensive analysis of high resolution atmospheric spectra recorded in the middle-infrared region to obtain simultaneous measurements of coupled parameters (gas concentrations of key trace constituents, total column amounts, pressure, and temperature) in the stratosphere and upper troposphere. Solar absorption spectra recorded at 0.002 and 0.02 cm exp -1 resolutions with the University of Denver group's balloon-borne, aircraft borne, and ground-based interferometers and 0.005 to 0.01 cm exp -1 resolution solar spectra from Kitt Peak are used in the analyses.

  14. Soil and litter exchange of reactive trace gases

    EPA Science Inventory

    The soil and litter play an important role in the exchange of trace gases between terrestrial ecosystems and the atmosphere. - The exchange of ammonia between vegetation and the atmosphere is highly influenced by soil and litter emissions especially in managed ecosystems (grassla...

  15. Remote sensing of atmospheric trace gases by diode laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Jianguo; Kan, Ruifeng; He, Yabai; He, Ying; Zhang, Yujun; Xie, Pinhua; liu, Wenqing

    2016-04-01

    Gaseous ammonia is the most abundant alkaline trace gas in the atmosphere. In order to study its role in acid deposition and aerosol formation, as well as its influence on the regional air quality and atmospheric visibility, several instruments has been developed based on TDLAS (Tunable Diode Laser Absorption Spectroscopy) techniques. In this paper, a long open path TDLAS system and a continuous-wave CRDS (Cavity-Ring down Spectroscopy) system are presented. The long open path system has been developed for NH3 in-situ monitoring by combining wavelength modulation with harmonic detection techniques to obtain the necessary detection sensitivity. The prototype instrument has been used to monitor atmospheric NH3 concentration at an urban site near Beijing National Stadium during Beijing Olympics in 2008, and recently used to measure the fluxes of NH3 from farm fields by flux-gradient method. The detection limit for ammonia is proved approximately 3ppb for a total path length of 456m. The continuous-wave, rapidly swept CRDS system has been developed for localized atmospheric sensing of trace gases at remote sites. Passive open-path optical sensor units could be coupled by optical fiber over distances of >1 km to a single transmitter/receiver console incorporating a photodetector and a swept-frequency diode laser tuned to molecule-specific near-infrared wavelengths. A noise-limited minimum detectable mixing ratio of ~11 ppbv is attained for ammonia at atmospheric pressure. The developed instruments are deployable in agricultural, industrial, and natural atmospheric environments.

  16. Atmospheric trace gases monitoring by UV-vis spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Xie, Pinhua; Li, Ang; Wu, Fengcheng; Qin, Min; Hu, Rezhi; Xu, Jin; Si, Fuqi; Liu, Jianguo; Liu, Wenqing

    2016-04-01

    Due to rapidly economic development, air pollution has become an important issue in China. Phenomena such as regional haze in winter and high O3 concentration in summer are strongly related to increasing trace species. For better understanding the air pollution formation, it is necessary to know spatial and temporal distribution of trace species in the atmosphere. UV-vis spectroscopic techniques are of great advantages for trace species monitoring to meet several requirements, e.g. versatility, high sensitivity, good temporal resolution and field applicability. We have studied and developed various trace gases monitoring techniques and instruments based on UV-vis spectroscopic technique for in-situ measurements and remote sensing, e.g. LP-DOAS, IBBCEAS, CRDS, MAX-DOAS and mobile DOAS for NO2, SO2, HCHO, HONO, NO3, and N2O5 etc. The principle, instrumentation and inversion algorithm are presented. As typical applications of these techniques, investigation of the evolution of HONO and NO3 radicals over Beijing area, measurements of regional pollution in NCP and YRD are discussed in the aspects of HONO and nocturnal NO3 radical characteristics, trace gases (NO2, SO2 etc.) temporal and spatial distribution, pollution transport pathway, emission sources.

  17. Greenhouse effect of chlorofluorocarbons and other trace gases

    NASA Astrophysics Data System (ADS)

    Hansen, James; Lacis, Andrew; Prather, Michael

    1989-11-01

    A comparison is made of the radiative (greenhouse) forcing of the climate system due to changes of atmospheric chlorofluorocarbons and other trace gases. It is found that CFCs, defined to include chlorofluorocarbons, chlorocarbons, and fluorocarbons, now provide about one-quater of current annual increases in anthropogenic greenhouse climate forcing. If the growth rates of CFC production in the early 1970s had continued to the present, current annual growth of climate forcing due to CFCs would exceed that due to CO2.

  18. Greenhouse effect of chlorofluorocarbons and other trace gases

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lacis, Andrew; Prather, Michael

    1989-01-01

    A comparison is made of the radiative (greenhouse) forcing of the climate system due to changes of atmospheric chlorofluorocarbons and other trace gases. It is found that CFCs, defined to include chlorofluorocarbons, chlorocarbons, and fluorocarbons, now provide about one-quater of current annual increases in anthropogenic greenhouse climate forcing. If the growth rates of CFC production in the early 1970s had continued to the present, current annual growth of climate forcing due to CFCs would exceed that due to CO2.

  19. Responses of trace gases to hydrologic pulses in desert floodplains

    NASA Astrophysics Data System (ADS)

    Harms, Tamara K.; Grimm, Nancy B.

    2012-03-01

    Pulsed hydrologic inputs interact with antecedent moisture conditions to shape biogeochemical dynamics in many ecosystems, but the outcomes of these interactions remain difficult to predict. Hydrologic pulses may influence biogeochemical activity through several mechanisms: by providing water as a resource, providing limiting nutrients or substrates that fuel particular biogeochemical pathways, or determining redox conditions. Antecedent moisture conditions may modify the relative importance of each of these potential mechanisms, by influencing accumulation of labile carbon and nutrients, the severity of water limitation to biological processes, and longer-term effects on abiotic conditions, including redox. We experimentally applied hydrologic pulses of different sizes (1-cm and 20-cm events) to soils of desert floodplains and assessed responses of trace gases (CO2, CH4, NO, and N2O) in dry and monsoon seasons to test these mechanisms. Size of the hydrologic pulse strongly interacted with antecedent soil-moisture conditions to determine emissions of some trace gases. Following dry antecedent conditions, water addition stimulated emissions of CO2, CH4, and NO, but not N2O, and larger experimental pulses resulted in larger fluxes. In the monsoon season, responses to water addition were muted and size of the hydrologic pulse had no effect, except for CH4emission, which increased in response to the 20-cm event. Seasonal contrasts indicated that antecedent moisture conditions constrain the effects of hydrologic pulses on biogeochemical processes, whereas contrasts among responses of different trace gases demonstrated that mechanisms controlling emissions of particular gases are water limitation (CO2), in situ production of nitrogen substrates (NO), or redox conditions (CH4). Strong and predictable interactive effects of water inputs and antecedent conditions indicate that extended droughts may cause elevated emissions of gaseous C and NO following the return of

  20. Patterns of trace gases near sources of global pollution

    SciTech Connect

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

    1990-08-01

    Many trace gases are increasing in the earth's armosphere and may couase global environmental changes in the future. Consequently there has been growing interest in the cycles of the long-lived gases that are likely to contribute the most to global change. At present there are four such gases: methane (CH{sub 4}), nitrous oxide (N{sub 2}0), trichlorofluoromethane (CCl{sub 3}F,F-11), and dichlorodifluoromethane (CCl{sub 2}F{sub 2},F-12). Methane and N{sub 2}O are involved mostly in adding to the greenhouse effect with some role in the stratospheric ozone cycle, and the two main fluorocarbons (F-11 and F-12) are involved in the depletion of the ozone layer with some role in global warming. This paper is about the patterns of these trace gases near regions of global scale pollution. Our purpose is to provide a synthesis of observations from diverse environments and ecosystems of the world and to provide readers with intuitive connections between sources and concentrations. We will consider four types of regions: rice fields in CHina that are a major source of methane, urban areas of the United States and China that are sources of fluorocarbons and other gases, rivers and surrounding wetlands, specifically the Yangtze in China and the Amazon in Brazil, and finally the environment of Boola Boola National Forest in Australia populated by many speices of termites that are a source of methane to the atmosphere. Eventually these patterns can be translated into estimeates of fluxes from the various sources of global pollution.

  1. Biogenic and anthropogenic trace gases in the atmosphere

    NASA Technical Reports Server (NTRS)

    Brasseur, G. P.; Prinn, R. G.

    1992-01-01

    This paper illustrates the importance of biogenic and anthropogenic trace gases for the global environment and for the climate system. The paper briefly reviews the currently available estimates of sources and strengths of the biogenic and anthropogenic gases on the global scale. One of the major concerns for the global environment is the rapid increase in the concentration of long-lived trace gases such as CO2, CH4, N2O and the chlorofluorocarbons. The trend in the carbon dioxide concentration, as a result of fossil-fuel burning, is of the order of 0.4 percent per year, and this trend is related to the CO2 uptake by the ocean and by terrestrial ecosystems, which are likely to be modified if the planet warms up in the forthcoming decades. The concentrations of methane and nitrous oxide are increasing by 0.9 and 0.25 percent per year, respectively. In the case of the most widely used chlorofluorocarbons, trends as large as 10 percent per year or more are being measured.

  2. Epiphytic cryptogams as a source of bioaerosols and trace gases

    NASA Astrophysics Data System (ADS)

    Ruckteschler, Nina; Hrabe de Angelis, Isabella; Zartman, Charles E.; Araùjo, Alessandro; Pöschl, Ulrich; Manzi, Antonio O.; Andreae, Meinrat O.; Pöhlker, Christopher; Weber, Bettina

    2016-04-01

    Cryptogamic covers comprise (cyano-)bacteria, algae, lichens, bryophytes, fungi, and archaea in varying proportions. These organisms do not form flowers, but reproduce by spores or cell cleavage with these reproductive units being dispersed via the atmosphere. As so-called poikilohydric organisms they are unable to regulate their water content, and their physiological activity pattern mainly follows the external water conditions. We hypothesize, that both spore dispersal and the release of trace gases are governed by the moisture patterns of these organisms and thus they could have a greater impact on the atmosphere than previously thought. In order to test this hypothesis, we initiated experiments at the study site Amazonian Tall Tower Observatory (ATTO) in September 2014. We installed microclimate sensors in epiphytic cryptogams at four different heights of a tree to monitor the activity patterns of these organisms. Self-developed moisture probes are used to analyze the water status of the organisms accompanied by light and temperature sensors. The continuously logged data are linked to ongoing measurements of trace gases and particulate bioaerosols to analyze these for the relevance of cryptogams. Here, we are particularly interested in diurnal cycles of coarse mode particles and the atmospheric abundance of fine potassium-rich particles from a currently unknown biogenic source. Based upon the results of this field study we also investigate the bioaerosol and trace gas release patterns of cryptogamic covers under controlled conditions. With this combined approach of field and laboratory experiments we aim to disclose the role of cryptogamic covers in bioaerosol and trace gas release patterns in the Amazonian rainforest.

  3. Source compositions of trace gases released during African savanna fires

    NASA Astrophysics Data System (ADS)

    Cofer, Wesley R.; Levine, Joel S.; Winstead, Edward L.; Cahoon, Donald R.; Sebacher, Daniel I.; Pinto, Joseph P.; Stocks, Brian J.

    1996-10-01

    Measurements of biomass burn-produced trace gases were made using low-altitude helicopter penetrations of smoke plumes above burning African savanna during the Southern African Fire-Atmosphere Research Initiative (SAFARI-92). Smoke from two large prescribed fires conducted in the Kruger National Park, South Africa, on September 18 and 24, 1992, was sampled at altitudes ranging from 20 to 100 m above ground level during flaming and smoldering phases of combustion. Carbon dioxide (CO2) normalized emission ratios (dX/dCO2 (vol/vol), where X denotes a trace gas) for carbon monoxide (CO), hydrogen (H2), methane (CH4), total nonmethane hydrocarbons (TNMHC), and nitrous oxide (N2O) were determined. The emission ratios were used in conjunction with fuel consumption estimates to calculate emission factors (grams of product per gram of fuel) for these gases. Emission factors for CO2, CO, CH4, and N2O of 1.61, 0.055, 0.003, and 1.6 × 10-4 g/g fuel, respectively, were determined. The fires advanced rapidly through the savanna (primarily grass) fuels with minimal amounts of smoldering combustion. The relatively low emission ratios determined for these fires indicated excellent combustion efficiency. About 93% of the carbon released into the atmosphere as a result of these fires was in the form of CO2.

  4. Climate-active Trace Gases from ACE Satellite Observations

    NASA Astrophysics Data System (ADS)

    Bernath, P. F.; Brown, A.; Harrison, J.; Chipperfield, M.; Boone, C.; Wilson, C.; Walker, K. A.

    2011-12-01

    ACE (also known as SCISAT) is making a comprehensive set of simultaneous measurements of more than 30 trace gases, thin clouds, aerosols and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4400 cm-1) is measuring the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. Launched by NASA in August 2003 for a nominal two-year mission, ACE performance remains excellent after 8 years in orbit. Volume mixing ratio (VMR) profiles of sixteen halogenated trace gases are routinely retrieved from ACE-FTS atmospheric spectra: CCl4, CF4, CCl3F (CFC-11), CCl2F2 (CFC-12), C2Cl3F3 (CFC-113), CH3Cl, ClONO2, COF2, COCl2, COClF, CHF2Cl (HCFC-22), CH3CCl2F (HCFC-141b), CH3CClF2 (HCFC-142b), HCl, HF and SF6. ACE also provides VMR profiles for CH4, N2O and OCS; HCFC-23 (CHF3) is a recent research product. ACE-FTS measurements were compared to surface measurements made by the AGAGE network and output from the SLIMCAT three-dimensional (3-D) chemical transport model, which is constrained by similar surface data. ACE-FTS measurements of CFCs (and HCl) show declining trends which agree with both AGAGE and SLIMCAT values. The concentrations of HCFCs are increasing with ACE-FTS, SLIMCAT and AGAGE all showing positive trends. These results illustrate the success of the Montreal Protocol in reducing ozone depleting substances. The replacement of CFCs with HCFCs has led to an increase in the VMR of HF in the stratosphere. As chlorine containing compounds continue to be phased out and replaced by fluorine-containing molecules, it is likely that total atmospheric fluorine will continue increasing in the near future. These species are all powerful greenhouse gases. ACE provides near global VMR

  5. Measurements of Trace Gases Using a Tunable Diode Laser

    NASA Technical Reports Server (NTRS)

    Jost, Hans-Juerg

    2005-01-01

    This report is the final report for "Measurements of Trace Gases Using a Tunable Diode Laser." The tasks outlined in the proposal are listed below with a brief comment. The publications and the conference presentations are listed. Finally, the important publications are attached. The Cooperative Agreement made possible a research effort to produce high- precision and high-accuracy in-situ measurements of carbon monoxide, methane and nitrous oxide on the WB-57 during the CRYSTAL-FACE and pre-AVE field campaigns and to analyze these measurements. These measurements of CO and CH4 were of utmost importance to studies of the radiative effects of clouds. Some important results of the CRYSTAL-FACE program were contained in two scientific papers (attached). This Cooperative Agreement allowed the participation of the Argus instrument in the program and the analysis of the data.

  6. Atmospheric trace gases and global climate - A seasonal model study

    NASA Technical Reports Server (NTRS)

    Wang, Wei-Chyung; Molnar, Gyula; Ko, Malcolm K. W.; Goldenberg, Steven; Sze, Nien Dak

    1990-01-01

    Atmospheric models with seasonal cycles are used to study the possible near-future changes in latitudinal and vertical distributions of atmospheric ozone and temperature caused by increases of trace gases. It is found that increases of CFCs, CH4, and N2O may add to the surface warming from increased CO2. Calculations based on projected trends of CO2, N2O, CH4, and CFCs show that the annual mean and global mean surface temperature could warm by as much as 2.5 C by the year 2050, with larger warming at high latitudes. The results suggest that the warming in the lower stratosphere and upper troposphere is much larger than that at the surface, especially during the summer season.

  7. Climate-chemical interactions and greenhouse effects of trace gases

    NASA Technical Reports Server (NTRS)

    Shi, Guang-Yu; Fan, Xiao-Biao

    1994-01-01

    A completely coupled one-dimensional radiative-convective (RC) and photochemical-diffusion (PC) model has been developed recently and used to study the climate-chemical interactions. The importance of radiative-chemical interactions within the troposphere and stratosphere has been examined in some detail. We find that increases of radiatively and/or chemically active trace gases such as CO2, CH4 and N2O have both the direct effects and the indirect effects on climate change by changing the atmospheric O3 profile through their interaction with chemical processes in the atmosphere. It is also found that the climatic effect of ozone depends strongly on its vertical distribution throughout the troposphere and stratosphere, as well on its column amount in the atmosphere.

  8. Sensitivity of RF-driven Plasma Filaments to Trace Gases

    NASA Astrophysics Data System (ADS)

    Burin, M. J.; Czarnocki, C. J.; Czarnocki, K.; Zweben, S. J.; Zwicker, A.

    2011-10-01

    Filamentary structures have been observed in many types of plasma discharges in both natural (e.g. lightning) and industrial systems (e.g. dielectric barrier discharges). Recent progress has been made in characterizing these structures, though various aspects of their essential physics remain unclear. A common example of this phenomenon can be found within a toy plasma globe (or plasma ball), wherein a primarily neon gas mixture near atmospheric pressure clearly and aesthetically displays filamentation. Recent work has provided the first characterization of these plasma globe filaments [Campanell et al., Physics of Plasmas 2010], where it was noticed that discharges of pure gases tend not to produce filaments. We have extended this initial work to investigate in greater detail the dependence of trace gases on filamentation within a primarily Neon discharge. Our preliminary results using a custom globe apparatus will be presented, along with some discussion of voltage dependencies. Newly supported by the NSF/DOE Partnership in Basic Plasma Science and Engineering.

  9. Volatile organic trace gases emitted from North American wildfires

    NASA Astrophysics Data System (ADS)

    Friedli, H. R.; Atlas, E.; Stroud, V. R.; Giovanni, L.; Campos, T.; Radke, L. F.

    2001-06-01

    Trace gases from wildfires and prescribed burns were collected from the National Science Foundation (NSF)/National Center for Atmospheric Research (NCAR) C-130 aircraft at fire locations in temperate forests (Montana, Colorado) and sage scrub (California). Comprehensive compositions for hydrocarbons, partially oxidized hydrocarbons (POHC), halocarbons, alkyl nitrates, and some sulfur compounds were determined in 99 samples. All of these trace gas emission groups correlated linearly with CO emissions. Fires in temperate forests emitted ˜28% more nonmethane hydrocarbons (NMHC) and 120% more POHC than the California fire and the molecular weight range of the emitted hydrocarbons was higher. The POHC contribution relative to NMHC emissions is significant: 26 and 38% for California and temperate forests, respectively. Since the observed POHCs (mostly ketones, aldehydes, and furans) typically react faster than many NMHC and undergo cascades of photochemical degradations, they should be included in calculations of the effect that fires have on the local and global oxidative capacity of the atmosphere. The composition of the hydrocarbons and POHCs in the plumes varied with combustion efficiency, displaying a distinct pattern, which reflected fire chemistry. Interfire differences were evident among fires in temperate forests. The dominant halocarbon emissions from all fires were methyl halides. The emission ratio was always largest for methyl chloride and was dependent on vegetation and fire location. C1-C5 alkyl nitrates were found in all fire emissions and showed little dependence on the location of the fire. The major organic sulfur compound measured was carbonyl sulfide. Minor amounts of dimethyl sulfide and dimethyl disulfide were observed. Budget estimates for emissions from fires in temperate forests were made based on the measured emission ratios and published carbon monoxide estimates.

  10. Trace gases in the atmosphere over Russian cities

    NASA Astrophysics Data System (ADS)

    Elansky, Nikolai F.; Lavrova, Olga V.; Skorokhod, Andrey I.; Belikov, Igor B.

    2016-10-01

    Multiyear observational data (obtained at the mobile railroad laboratory in the course of the 1995-2010 TROICA experiments) on the composition and state of the atmosphere were used to study the features of both spatial and temporal variations in the contents of trace gases in the surface air layer over Russian cities. The obtained characteristics of urban air noticeably differ from those obtained at stationary stations. The emission fluxes of NOx, CO, and CH4 and their integral emissions from large cities have been estimated on the basis of observational data obtained at the mobile laboratory. The values of these emission fluxes reflect the state of urban infrastructure. The integral urban emissions of CO depend on the city size and vary from 50 Gg yr-1 for Yaroslavl to 130 Gg yr-1 for Yekaterinburg. For most cities, they agree with the EDGAR v4.2 data within the limits of experimental error. The agreement is worse for the emissions of NOx. The EDGAR v4.2 data on the emissions of CH4 seem to be overestimated.

  11. Microwave limb sounder. [measuring trace gases in the upper atmosphere

    NASA Technical Reports Server (NTRS)

    Gustincic, J. J. (Inventor)

    1981-01-01

    Trace gases in the upper atmosphere can be measured by comparing spectral noise content of limb soundings with the spectral noise content of cold space. An offset Cassegrain antenna system and tiltable input mirror alternately look out at the limb and up at cold space at an elevation angle of about 22. The mirror can also be tilted to look at a black body calibration target. Reflection from the mirror is directed into a radiometer whose head functions as a diplexer to combine the input radiation and a local ocillator (klystron) beam. The radiometer head is comprised of a Fabry-Perot resonator consisting of two Fabry-Perot cavities spaced a number of half wavelengths apart. Incoming radiation received on one side is reflected and rotated 90 deg in polarization by the resonator so that it will be reflected by an input grid into a mixer, while the klystron beam received on the other side is also reflected and rotated 90 deg, but not without passing some energy to be reflected by the input grid into the mixer.

  12. Biogenic trace gases in the atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Jahangeer, Muffarah

    Trace gases are known to exert a tremendous influence on planetary atmospheres. By understanding spatial and temporal trace gas behavioral patterns vast amounts of information about the celestial body can be deduced, from current conditions to past history to future evolution. The discovery of episodic methane plumes on Mars argues the presence of ethane, regardless of origin, biogenic or abiogenic, even though it has yet to be detected there. The Earth's methane is produced both by serpentinization as well as by Archaean methanogens. Methane is a potent greenhouse gas and large methane excursions on Earth have been linked with dramatic shifts in its climate, as with the Permian-Triassic extinction event. Atmospheric ethane while present on Earth at about 0.5 ppbv, results primarily from the photochemical action on methane gas. Ultraviolet photons of wavelengths shorter than 160 nm dissociate methane to a methyl radical and one hydrogen atom. When two methyl radicals recombine, the result is ethane: CH4+hv→CH3• +•H CH3•+•CH3+M→C2H6+M A small fraction of terrestrial ethane is also produced by methanogens and ethanogens. Ethane is a constituent of the atmospheres of all four outer solar system planetary bodies as well as of some moons and comets but has not yet been explored or studied in Mars. Possible mechanisms that control the synthesis, occurrence and lifetime of ethane in the atmosphere of Mars are examined in this study along with the Martian trace gas profile using a 1-D photochemical model of its atmosphere. Upper limits of the flux of ethane used are based on our understanding of the Earth's atmospheric component of ethane and vertical patterns of lifetime, mixing ratio and kinetic reaction rates probed from the regolith to 240km. Ethane molecules are heavier and exhibit "creep" and pooling on the ground, allowing it to linger at the regolith. Ethane also benefits from shielding by methane molecules, allowing some ethane to persist at higher

  13. Titan's temporal evolution in stratospheric trace gases near the poles

    NASA Astrophysics Data System (ADS)

    Coustenis, Athena; Jennings, Donald E.; Achterberg, Richard K.; Bampasidis, Georgios; Lavvas, Panayiotis; Nixon, Conor A.; Teanby, Nicholas A.; Anderson, Carrie M.; Cottini, Valeria; Flasar, F. Michael

    2016-05-01

    We analyze spectra acquired by the Cassini/Composite Infrared Spectrometer (CIRS) at high resolution from October 2010 until September 2014 in nadir mode. Up until mid 2012, Titan's Northern atmosphere exhibited the enriched chemical content found since the Voyager days (November 1980), with a peak around the Northern Spring Equinox (NSE) in 2009. Since then, we have observed the appearance at Titan's south pole of several trace species for the first time, such as HC3N and C6H6, observed only at high northern latitudes before equinox. We investigate here latitudes poleward of 50°S and 50°N from 2010 (after the Southern Autumnal Equinox) until 2014. For some of the most abundant and longest-lived hydrocarbons (C2H2, C2H6 and C3H8) and CO2, the evolution in the past 4 years at a given latitude is not very significant within error bars especially until mid-2013. In more recent dates, these molecules show a trend for increase in the south. This trend is dramatically more pronounced for the other trace species, especially in 2013-2014, and at 70°S relative to 50°S. These two regions then demonstrate that they are subject to different dynamical processes in and out of the polar vortex region. For most species, we find higher abundances at 50°N compared to 50°S, with the exception of C3H8, CO2, C6H6 and HC3N, which arrive at similar mixing ratios after mid-2013. While the 70°N data show generally no change with a trend rather to a small decrease for most species within 2014, the 70°S results indicate a strong enhancement in trace stratospheric gases after 2012. The 663 cm-1 HC3N and the C6H6 674 cm-1 emission bands appeared in late 2011/early 2012 in the south polar regions and have since then exhibited a dramatic increase in their abundances. At 70°S HC3N, HCN and C6H6 have increased by 3 orders of magnitude over the past 3-4 years while other molecules, including C2H4, C3H4 and C4H2, have increased less sharply (by 1-2 orders of magnitude). This is a strong

  14. Observations of atmospheric trace gases by MAX-DOAS in the coastal boundary layer over Jiaozhou Bay

    NASA Astrophysics Data System (ADS)

    Li, Xianxin; Wang, Zhangjun; Meng, Xiangqian; Zhou, Haijin; Du, Libin; Qu, Junle; Chen, Chao; An, Quan; Wu, Chengxuan; Wang, Xiufen

    2014-11-01

    Atmospheric trace gases exist in the atmosphere of the earth rarely. But the atmospheric trace gases play an important role in the global atmospheric environment and ecological balance by participating in the global atmospheric cycle. And many environmental problems are caused by the atmospheric trace gases such as photochemical smog, acid rain, greenhouse effect, ozone depletion, etc. So observations of atmospheric trace gases become very important. Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) developed recently is a kind of promising passive remote sensing technology which can utilize scattered sunlight received from multiple viewing directions to derive vertical column density of lower tropospheric trace gases like ozone, sulfur dioxide and nitrogen dioxide. It has advantages of simple structure, stable running, passive remote sensing and real-time online monitoring automatically. A MAX-DOAS has been developed at Shandong Academy of Sciences Institute of Oceanographic Instrumentation (SDIOI) for remote measurements of lower tropospheric trace gases (NO2, SO2, and O3). In this paper, we mainly introduce the stucture of the instrument, calibration and results. Detailed performance analysis and calibration of the instrument were made at Qingdao. We present the results of NO2, SO2 and O3 vertical column density measured in the coastal boundary layer over Jiaozhou Bay. The diurnal variation and the daily average value comparison of vertical column density during a long-trem observation are presented. The vertical column density of NO2 and SO2 measured during Qingdao oil pipeline explosion on November 22, 2013 by MAX-DOAS is also presented. The vertical column density of NO2 reached to a high value after the explosion. Finally, the following job and the outlook for future possible improvements are given. Experimental calibration and results show that the developed MAX-DOAS system is reliable and credible.

  15. Halocarbons and other trace heteroatomic organic compounds in volcanic gases from Vulcano (Aeolian Islands, Italy)

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Seward, Terry M.; Giże, Andrew P.; Hall, Keith; Dietrich, Volker J.

    2013-01-01

    Adsorbent-trapped volcanic gases, sublimates and condensates from active vents of the La Fossa crater on the island of Vulcano (Aeolian Islands, Italy) as well as ambient and industrial air were quantitatively analyzed by Short-Path Thermal Desorption-Solid Phase Microextraction-Cryotrapping-Gas Chromatography/Mass Spectrometry (SPTD-SPME-CF-GC-MS). Among the over 200 detected and quantified compounds are alkanes, alkenes, arenes, phenols, aldehydes, carboxylic acids, esters, ketones, nitriles, PAHs and their halogenated, methylated and sulfonated derivatives, as well as various heterocyclic compounds including thiophenes and furans. Most compounds are found at concentrations well above laboratory, ambient air, adsorbent and field blank levels. For some analytes (e.g., CFC-11, CH2Cl2, CH3Br), concentrations are up to several orders of magnitude greater than even mid-latitudinal industrial urban air maxima. Air or laboratory contamination is negligible or absent on the basis of noble gas measurements and their isotopic ratios. The organic compounds are interpreted as the product of abiogenic gas-phase radical reactions. On the basis of isomer abundances, n-alkane distributions and substitution patterns the compounds are thought to have formed by high-temperature (e.g., 900 °C) alkyl free radical reactions and halide electrophilic substitution on arenes, alkanes and alkenes. The apparent abiogenic organic chemistry of volcanic gases may give insights into metal transport processes during the formation and alteration of hydrothermal ore deposits, into the natural volcanic source strength of ozone-depleting atmospheric trace gases (i.e., halocarbons), into possibly sensitive trace gas redox pairs as potential early indicators of subsurface changes on volcanoes in the state of imminent unrest, and into the possible hydrothermal origin of early life on Earth, as indicated by the presence of simple amino acids, nitriles, and alkanoic acids.

  16. Ozone and other trace gases in the Arctic and Antarctic regions: Three-dimensional model simulations

    SciTech Connect

    Granier, C.; Brasseur, G. )

    1991-02-20

    A three-dimensional mechanistic model of the middle atmosphere with calculated dynamics and chemistry is used to study the behavior of chemically active trace gases at high latitudes in winter and spring, and to simulate the formation of an ozone hole in Antarctica. The dynamics of both hemispheres is simulated by applying at the lower boundary of the model (8.5 km) a wavelike perturbation representing qualitatively a climatological tropospheric forcing. The chemical heterogeneous processes converting chlorine reservoirs into active chlorine in cold air masses are parameterized. The model simulates the behavior of nitrogen oxides, nitric acid, water vapor, methane, hydrogen radicals, chlorine compounds, and ozone. It reproduces important features observed during different Antarctic and Arctic observation campaigns. The ozone hole in the southern hemisphere can only be simulated when the heterogeneous polar chemistry is taken into account. The springtime ozone depletion over Antarctica calculated in the model is thus mostly the result of chemical removal although the dynamics is responsible for the low temperature that triggers the large ozone loss rates. Unresolved questions are related to the strength of the vertical exchanges inside the vortex, the preconditioning of trace gases before and during the winter season, the behavior of the different trace gases as the vortex breaks down (dilution effects), accurate determination of the ozone sink inside the vortex, and a better quantitative estimation of the role of polar stratospheric clouds. Despite elevated concentrations of active chlorine at high latitudes in the northern hemisphere in late winter, no ozone hole is produced by the model, even with chlorine levels as high as 6 ppbv. This conclusion could, however, be modified for very stable and cold winters with delayed final warming.

  17. Pilot Institute on Global Change on Trace Gases and the Biosphere, 1988

    NASA Technical Reports Server (NTRS)

    Eddy, J. A.; Moore, B.

    1998-01-01

    Table of Contents: Summary; Background; General Framework for a Series of Institutes on Global Change; The 1988 Pilot Institute on Global Changes: Trace Gases and the Biosphere; Budget; List of Acronyms; and Attachments.

  18. Processes to remove acid forming gases from exhaust gases

    DOEpatents

    Chang, S.G.

    1994-09-20

    The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO[sub 2]; (B) contacting the gas sample of step (A) comprising NO[sub 2] with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0 and 100 C at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environmentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed. 16 figs.

  19. Optical parametric oscillators in lidar sounding of trace atmospheric gases in the mid infrared region

    NASA Astrophysics Data System (ADS)

    Romanovskii, O. A.; Sadovnikov, S. A.; Kharchenko, O. V.; Shumskii, V. K.; Yakovlev, S. V.

    2015-12-01

    Applicability of a KTA crystal-based laser system with optical parametric generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases is based on differential absorption (DIAL) technique and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases.

  20. MIRAGE: Model Description and Evaluation of Aerosols and Trace Gases

    SciTech Connect

    Easter, Richard C.; Ghan, Steven J.; Zhang, Yang; Saylor, Rick D.; Chapman, Elaine G.; Laulainen, Nels S.; Abdul-Razzak, Hayder; Leung, Lai-Yung R.; Bian, Xindi; Zaveri, Rahul A.

    2004-10-27

    The MIRAGE (Model for Integrated Research on Atmospheric Global Exchanges) modeling system, designed to study the impacts of anthropogenic aerosols on the global environment, is described. MIRAGE consists of a chemical transport model coupled on line with a global climate model. The chemical transport model simulates trace gases, aerosol number, and aerosol chemical component mass [sulfate, MSA, organic matter, black carbon (BC), sea salt, mineral dust] for four aerosol modes (Aitken, accumulation, coarse sea salt, coarse mineral dust) using the modal aerosol dynamics approach. Cloud-phase and interstitial aerosol are predicted separately. The climate model, based on the CCM2, has physically-based treatments of aerosol direct and indirect forcing. Stratiform cloud water and droplet number are simulated using a bulk microphysics parameterization that includes aerosol activation. Aerosol and trace gas species simulated by MIRAGE are presented and evaluated using surface and aircraft measurements. Surface-level SO2 in N. American and European source regions is higher than observed. SO2 above the boundary layer is in better agreement with observations, and surface-level SO2 at marine locations is somewhat lower than observed. Comparison with other models suggests insufficient SO2 dry deposition; increasing the deposition velocity improves simulated SO2. Surface-level sulfate in N. American and European source regions is in good agreement with observations, although the seasonal cycle in Europe is stronger than observed. Surface-level sulfate at high-latitude and marine locations, and sulfate above the boundary layer, are higher than observed. This is attributed primarily to insufficient wet removal; increasing the wet removal improves simulated sulfate at remote locations and aloft. Because of the high sulfate bias, radiative forcing estimates for anthropogenic sulfur in Ghan et al. [2001c] are probably too high. Surface-level DMS is {approx}40% higher than observed

  1. Trace anesthetic gases during xenon arc photocoagulation for retinoblastoma.

    PubMed

    Rosenberg, A M; Abramson, D H; Sussman, D; Servodidio, C; Turner, L

    1989-10-01

    In pediatric ocular examinations, administration of continuous-flow anesthetic gases containing nitrous oxide, halothane, and oxygen enables the physician to do safe, controlled, reproducible examinations. We did a study in which the levels of waste anesthetic gases were measured during xenon arc photocoagulation procedures used for retinoblastoma. Waste nitrous oxide and halothane gases measured during these procedures significantly exceeded the levels recommended by the National Institute of Safety and Health. These high levels are of particular importance because of the physician's proximity to the patient during the procedure. The high levels of waste gases may have immediate deleterious effects on the physician's functioning capacity and may also pose long-term health hazards for the physician and operating room personnel. PMID:2589745

  2. Processes to remove acid forming gases from exhaust gases

    DOEpatents

    Chang, Shih-Ger

    1994-01-01

    The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO.sub.2 ; (B) contacting the gas sample of step (A) comprising NO.sub.2 with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0.degree. and 100.degree. C. at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environ-mentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed.

  3. Atmospheric Trace Gases from the Carbon Dioxide Information Analysis Center (CDIAC)

    DOE Data Explorer

    CDIAC products are indexed and searchable through a customized interface powered by ORNL's Mercury search engine. Products include numeric data packages, publications, trend data, atlases, models, etc. and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Some of the collections may also be included in the CDIAC publication, Trends Online: A Compendium of Global Change Data. Most data sets, many with numerous data files, are free to download from CDIAC's ftp area. The collections under the CDIAC heading of Atmospheric Trace Gases include: Atmospheric Carbon Dioxide, Atmospheric Methane, Atmospheric Carbon Monoxide, Atmospheric Hydrogen, Isotopes in Greenhouse Gases, Radionuclides, Aerosols, and Other Trace Gases.

  4. Eddy correlation fluxes of trace gases using a tandem mass spectrometer

    NASA Astrophysics Data System (ADS)

    Shaw, William J.; Spicer, Chester W.; Kenny, Donald V.

    This paper describes a field evaluation of a tandem mass spectrometer (TAGA) for use in measuring turbulence fluxes of trace gases. Measurements were made over a two-day period in a fallow farm field west of Columbus, OH. The results show that for weakly adsorbing species such as acetone, the effective time constant for the TAGA is <0.1 s, and the device can be used for eddy correlation flux measurements with little need for corrections. The effective time constant is longer for adsorbing species, such as ammonia, but spectral corrections can permit flux estimates for these species as well. This paper presents the first reported measurements of fluxes of acetone, formic acid, and ammonia using the eddy correlation technique.

  5. A search for biogenic trace gases in the atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.; Mckay, Christopher P.

    1989-01-01

    The detection of certain trace gases in the atmosphere of Mars may serve as a possible indicator of microbial life on the surface of Mars. Candidate biogenic gases include methane CH4, ammonia NH3, nitrous oxide N2O, and several reduced sulfur species. Chemical thermodynamic equilibrium and photochemical calculations preclude the presence of these gases in any measurable concentrations in the atmosphere of Mars in the absence of biogenic production. A search for these gases utilizing either high resolution (spectral and spatial) spectroscopy from a Mars orbiter, such as the Observer, and or in situ measurements from a Mars lander or rover, is proposed.

  6. Trace gases in the atmosphere of Mars - An indicator of microbial life

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.; Rinsland, Curtis P.; Boston, Penelope J.; Cofer, Wesley R., III; Chameides, William L.

    1989-01-01

    The detection of certain trace gases in the atmosphere of Mars would indicate the presence of microbial life on the surface. Candidate biogenic gases include CH4, NH3, N2O, and several reduced sulfur species. Chemical thermodynamic equilibrium and photochemical calculations preclude the presence of these gases in any measurable concentrations in the atmosphere of Mars in the absence of biogenic production. A search for these gases utilizing either high-resolution (spectral and spatial) spectroscopy from a Mars orbiter, such as the Mars Observer orbiter, and/or in situ measurements from a Mars lander or rover is proposed.

  7. Trace water determination in gases by infrared spectroscopy

    SciTech Connect

    Stallard, B.R.; Espinoza, L.H.; Niemczyk, T.M.

    1995-05-01

    Water determination in semiconductor process gases is desirable in order to extend the life of gas delivery systems and improve wafer yields. The authors review their work in applying Fourier transform infrared spectroscopy to this problem, where a 10 ppb detection limit has been demonstrated for water in N{sub 2}, HCl, and HBr. The potential for optical determination of other contaminants in these gases is discussed. Also, alternative optical spectroscopic approaches are briefly described. Finally, they discuss methods for dealing with interference arising from water in the instrument beam path, yet outside the sample cell.

  8. Application of Derivative Spectrometry to the Analysis of Trace Gases

    NASA Technical Reports Server (NTRS)

    Hager, Robert N.

    1971-01-01

    A derivative spectrometer is sensitive to changes in spectral intensity over narrow wavelength internal. Specifically, a second derivative spectrometer senses the curvature of the incident spectral intensity, providing an output voltage signal proportional to the second derivative of intensity with respect to wavelength. When such an instrument is combined with multi-pass White cell, a unique trace gas analyzer results. The analyzer, operating within the middle ultraviolet spectral region, provides a highly amplified derivative spectrum of any molecular narrow band absorption which is used for trace gas identification. The intensity of any peak within a spectrum is proportional to the trace gas concentration. Such an analyzer, utilizing a 20 meter pathlength White cell, is presently being used to automatically monitor ambient air for SO2, NO, NO2, and O3 with minimum detectable concentration limits in the part per billion range.

  9. PHOTOENHANCED DEPOSITION OF TRACE GASES AT THE INTERFACE OF ORGANIC SURFACES

    NASA Astrophysics Data System (ADS)

    George, C.; Barbara, D.; Jammoul, A.; Favez, O.; Rosenoern, T.

    2009-12-01

    Atmospheric aerosol particles have been found to contain moderate to high fractions by mass of organic compounds. These may be biogenic or anthropogenic in origin, depending on the location and history of the individual particle. The recent and growing awareness of this has spurred a significant effort in understanding how organic compounds on particle surfaces influence water condensation there; how this changes as the particle becomes “processed” (i.e. oxidized) in the atmosphere, and how these processes influence the gas phase composition in volumes containing such particles. Most of these studies evaluated the uptakes or the deposition of some trace gases at the organic interface under dark conditions. However, very few investigations focus on the effect of solar irradiation on atmospheric heterogeneous chemistry, although recent findings confirm the presence of UV-A/Visible light absorbing material in airborne particles and environmental surfaces which can allow photo-induced (or photosensitized) processes. The present work demonstrates the photo-enhanced uptake of NO2 and O3 on various organic surfaces as various aromatic compounds used as proxy of biogenic and anthropogenic emissions (PAHs, phenolic compounds) and humic acid coatings and submicron particles. The results suggest that photo-induced uptake can be important under atmospheric conditions with respect irradiance, humidity, temperature and gas trace mixing ratio.

  10. Greenhouse effects due to man-made perturbations of trace gases

    NASA Technical Reports Server (NTRS)

    Wang, W. C.; Yung, Y. L.; Lacis, A. A.; Mo, T.; Hansen, J. E.

    1976-01-01

    Nitrous oxide, methane, ammonia, and a number of other trace constituents of the earth's atmosphere have infrared absorption bands in the spectral range from 7 to 14 microns. Despite their small amounts, these gases can have a significant effect on the thermal structure of the atmosphere by transmitting most of the thermal radiation from the earth's surface to the lower atmosphere. In the present paper, this greenhouse effect is computed for a number of trace gases. The nature and climatic implications of possible changes in the concentrations of N2O, CH4, NH3, and HNO3 are discussed.

  11. ENSO effects on stratospheric trace gases: How do we capture reality?

    NASA Astrophysics Data System (ADS)

    Braesicke, Peter; Kirner, Oliver; Versick, Stefan; Joeckel, Patrick; Stiler, Gabriele

    2016-04-01

    The El Niño/Southern Oscillation (ENSO) phenomenon is an important pacemaker for interannual variability in the Earth's atmosphere. ENSO impacts on trace gases have been observed and modelled for the stratosphere and the troposphere. However, unambiguous attribution is often difficult due to the limited length of homogenous observational records and thus long-term (decadal) trends are sometimes difficult to detect. Generally ENSO impacts in low latitudes are easier to detect, because the response emerges close (temporally and spatially) to the forcing. Moving from low to high latitudes it becomes increasingly difficult to isolate ENSO driven variability, due to time-lags involved and many other modes of variability playing a role as well. Here, we use a nudged version of the EMAC chemistry-climate model to evaluate ENSO impacts on trace gases over the last 35 years (a so-called Ref-C1SD integration) and contrast the nudged model with its free running counterpart. We use water vapour and ozone observations from the MIPAS instrument on ENVISAT from 2002 to 2012 to test the model performance. Using lagged correlations for the longer model time-series we trace the ENSO signal from the tropical lower troposphere to the polar lower and middle stratosphere and provide a framework for simple attribution of the ENSO signal in trace gases. This concise characterisation of the ENSO impact on trace gases aids improved trend detection in temporally limited time series.

  12. In situ measurements and modeling of reactive trace gases in a small biomass burning plume

    NASA Astrophysics Data System (ADS)

    Müller, Markus; Anderson, Bruce E.; Beyersdorf, Andreas J.; Crawford, James H.; Diskin, Glenn S.; Eichler, Philipp; Fried, Alan; Keutsch, Frank N.; Mikoviny, Tomas; Thornhill, Kenneth L.; Walega, James G.; Weinheimer, Andrew J.; Yang, Melissa; Yokelson, Robert J.; Wisthaler, Armin

    2016-03-01

    An instrumented NASA P-3B aircraft was used for airborne sampling of trace gases in a plume that had emanated from a small forest understory fire in Georgia, USA. The plume was sampled at its origin to derive emission factors and followed ˜ 13.6 km downwind to observe chemical changes during the first hour of atmospheric aging. The P-3B payload included a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), which measured non-methane organic gases (NMOGs) at unprecedented spatiotemporal resolution (10 m spatial/0.1 s temporal). Quantitative emission data are reported for CO2, CO, NO, NO2, HONO, NH3, and 16 NMOGs (formaldehyde, methanol, acetonitrile, propene, acetaldehyde, formic acid, acetone plus its isomer propanal, acetic acid plus its isomer glycolaldehyde, furan, isoprene plus isomeric pentadienes and cyclopentene, methyl vinyl ketone plus its isomers crotonaldehyde and methacrolein, methylglyoxal, hydroxy acetone plus its isomers methyl acetate and propionic acid, benzene, 2,3-butanedione, and 2-furfural) with molar emission ratios relative to CO larger than 1 ppbV ppmV-1. Formaldehyde, acetaldehyde, 2-furfural, and methanol dominated NMOG emissions. No NMOGs with more than 10 carbon atoms were observed at mixing ratios larger than 50 pptV ppmV-1 CO. Downwind plume chemistry was investigated using the observations and a 0-D photochemical box model simulation. The model was run on a nearly explicit chemical mechanism (MCM v3.3) and initialized with measured emission data. Ozone formation during the first hour of atmospheric aging was well captured by the model, with carbonyls (formaldehyde, acetaldehyde, 2,3-butanedione, methylglyoxal, 2-furfural) in addition to CO and CH4 being the main drivers of peroxy radical chemistry. The model also accurately reproduced the sequestration of NOx into peroxyacetyl nitrate (PAN) and the OH-initiated degradation of furan and 2-furfural at an average OH concentration of 7.45 ± 1.07 × 106 cm-3 in the

  13. In situ measurements and modeling of reactive trace gases in a small biomass burning plume

    NASA Astrophysics Data System (ADS)

    Müller, M.; Anderson, B.; Beyersdorf, A.; Crawford, J. H.; Diskin, G.; Eichler, P.; Fried, A.; Keutsch, F. N.; Mikoviny, T.; Thornhill, K. L.; Walega, J. G.; Weinheimer, A. J.; Yang, M.; Yokelson, R.; Wisthaler, A.

    2015-11-01

    An instrumented NASA P-3B aircraft was used for airborne sampling of trace gases in a plume that had emanated from a small forest understory fire in Georgia, USA. The plume was sampled at its origin for deriving emission factors and followed ~ 13.6 km downwind for observing chemical changes during the first hour of atmospheric aging. The P-3B payload included a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), which measured non-methane organic gases (NMOGs) at unprecedented spatio-temporal resolution (10 m/0.1 s). Quantitative emission data are reported for CO2, CO, NO, NO2, HONO, NH3 and 16 NMOGs (formaldehyde, methanol, acetonitrile, propene, acetaldehyde, formic acid, acetone plus its isomer propanal, acetic acid plus its isomer glycolaldehyde, furan, isoprene plus isomeric pentadienes and cyclopentene, methyl vinyl ketone plus its isomers crotonaldehyde and methacrolein, methylglyoxal, hydroxy acetone plus its isomers methyl acetate and propionic acid, benzene, 2,3-butandione and 2-furfural) with molar emission ratios relative to CO larger than 1 ppbV ppmV-1. Formaldehyde, acetaldehyde, 2-furfural and methanol dominated NMOG emissions. No NMOGs with more than 10 carbon atoms were observed at mixing ratios larger than 50 ppbV ppmV-1 CO emitted. Downwind plume chemistry was investigated using the observations and a 0-D photochemical box model simulation. The model was run on a near-explicit chemical mechanism (MCM v3.3) and initialized with measured emission data. Ozone formation during the first hour of atmospheric aging was well captured by the model, with carbonyls (formaldehyde, acetaldehyde, 2,3-butanedione, methylglyoxal, 2-furfural) in addition to CO and CH4 being the main drivers of peroxy radical chemistry. The model also accurately reproduced the sequestration of NOx into PAN and the OH-initiated degradation of furan and 2-furfural at an average OH concentration of 7.45 ± 1.07 × 106 cm-3 in the plume. Formaldehyde, acetone

  14. Titan's temporal evolution in stratospheric trace gases near the poles

    NASA Astrophysics Data System (ADS)

    Coustenis, A.; Jennings, D.; Achterberg, R.; Bampasidis, G.; Lavvas, P.; Nixon, C.; Teanby numeration="7">Teanby, N.; Anderson, C.; Cottini, V.; Flasar, F. M.

    2015-10-01

    We analyze spectra acquired by the Cassini/Composite Infrared Spectrometer (CIRS) at high resolution from October 2010 until September 2014 in nadir mode. Up until mid 2012, Titan's Northern atmosphere exhibited the enriched chemical content found since the Voyager days (November 1980), with a peak around the Northern Spring Equinox (NSE) in 2009. Since then, we have observed the appearance at Titan's south pole of several trace species for the first time, such as HC3N and C6H6, observed only at high northern latitudes before equinox. We investigate here latitudes poleward of 50°S and 50°N from 2010 (after the Southern Autumnal Equinox : SAE) until 2014.

  15. Atmospheric trace gases: trends and distributions over the last decade.

    PubMed

    Rasmussen, R A; Khalil, M A

    1986-06-27

    Concentrations of the halocrbons CCl(3)F (F-11), CCl(2)F(2) (F-12), CCl(4), and CH(3)CCl(3), methane (CH(4)), and nitrous oxide (N(2)O) over the decade between 1975 and 1985 are reported, based on measurements taken every January at the South Pole and in the Pacific Northwest. The concentrations of F-11, F-12, and CH(3)CCl(3) in both hemispheres are now more than twice their concentrations 10 years ago. However, the annual rates of increase of F-11, F-12, and CH(3)CC1(3) are now considerably slower than earlier in the decade, reflecting in part the effects of a ban on their nonessential uses. Continued increases in these trace gas concentrations may warm the earth and deplete the stratospheric ozone layer, which may cause widespread climatic changes and affect global habitability.

  16. Interannual variability of trace gases in the subtropical winter stratosphere

    SciTech Connect

    Gray, L.J.; Russell, J.M. III

    1999-04-01

    Measurements of water vapor and methane from the Halogen Occultation Experiment instrument on board the Upper Atmosphere Research Satellite are used to study the interannual variability of trace gas distributions in the atmosphere. Particular attention is paid to the mechanisms influencing trace gas distributions in the subtropics. The study highlights the quasi-biennial oscillation (QBO) dependence of subtropical tracer distributions more clearly than in previous studies. There is a strong correlation between the equatorial wind QBO and the slope of the tracer isolines in the Northern Hemisphere subtropics, with steeper subtropical isoline slopes in the easterly phase compared with the westerly phase. This is particularly so in the lower stratosphere. Two possible mechanisms for the QBO signal in subtropical isoline slopes are identified: advection by the mean circulation and isentropic mixing. A comparison between the QBO signal in the slope of the tracer isolines and the isentropic tracer gradients is proposed as a method of determining which process is dominant. The authors suggest that the behavior of these two data diagnostics provides a stringent constraint on computer models of the atmosphere. On the basis of these diagnostics three height regions of the subtropical atmosphere are identified. (1) Below 450--500 K isentropic mixing associated with tropospheric disturbances penetrating the lower stratosphere is dominant. (2) In the region 500--750 K the data suggest that advection by the mean meridional circulation is important and that the role of isentropic mixing by eddies is relatively small. (3) Above 750 K isentropic mixing becomes increasingly important with height, and both advection and mixing are influential in determining the subtropical tracer distributions.

  17. Effects of traces of molecular gases (hydrogen, nitrogen) in glow discharges in noble gases

    NASA Astrophysics Data System (ADS)

    Steers, E. B. M.; Smid, P.; Hoffmann, V.

    2008-07-01

    The "Grimm" type of low pressure glow discharge source, introduced some forty years ago, has proved to be a versatile analytical source. A flat sample is used as the cathode and placed about 0.2mm away from the end of a hollow tubular anode leading to an obstructed discharge. When the source was first developed, it was used for the direct analysis of solid metallic samples by optical emission spectroscopy (OES), normally with argon as the plasma gas; it was soon found that, using suitable electrical parameters, the cathode material was sputtered uniformly from a circular crater of diameter equal to that of the tubular anode, so that the technique could be used for compositional depth profile analysis (CDPA). Over the years the capability and applications of the technique have steadily increased. The use of rf powered discharges now permits the analysis of non-conducting layers and samples; improved instrumental design now allows CDPA of ever thinner layers (e.g. resolution of layers 5 nm thick in multilayer stacks is possible). For the original bulk material application, pre-sputtering could be used to remove any surface contamination but for CDPA, analysis must start immediately the discharge is ignited, so that any surface contamination can introduce molecular gases into the plasma gas and have significant analytical consequences, especially for very thin layers; in addition, many types of samples now analysed contain molecular gases as components (either as occluded gas, or e.g. as a nitride or oxide), and this gas enters the discharge when the sample is sputtered. It is therefore important to investigate the effect of such foreign gases on the discharge, in particular on the spectral intensities and hence the analytical results. The presentation will concentrate mainly on the effect of hydrogen in argon discharges, in the concentration range 0-2 % v/v but other gas mixtures (e.g. Ar/N_2, Ne/H_2) will be considered for comparison. In general, the introduction of

  18. Method for removing acid gases from a gaseous stream

    DOEpatents

    Gorin, Everett; Zielke, Clyde W.

    1981-01-01

    In a process for hydrocracking a heavy aromatic polynuclear carbonaceous feedstock containing reactive alkaline constituents to produce liquid hydrocarbon fuels boiling below about 475.degree. C. at atmospheric pressure by contacting the feedstock with hydrogen in the presence of a molten metal halide catalyst, thereafter separating a gaseous stream containing hydrogen, at least a portion of the hydrocarbon fuels and acid gases from the molten metal halide and regenerating the molten metal halide, thereby producing a purified molten metal halide stream for recycle to the hydrocracking zone, an improvement comprising; contacting the gaseous acid gas, hydrogen and hydrocarbon fuels-containing stream with the feedstock containing reactive alkaline constituents to remove acid gases from the acid gas containing stream. Optionally at least a portion of the hydrocarbon fuels are separated from gaseous stream containing hydrogen, hydrocarbon fuels and acid gases prior to contacting the gaseous stream with the feedstock.

  19. Observations of halogenated trace gases in Taiwan and Malaysia

    NASA Astrophysics Data System (ADS)

    Gooch, Lauren J.; Laube, Johannes C.; Sturges, William T.; Oram, David E.; Wang, Jia-Lin; Ou-Yang, Cheng-Feng; Lin, Neng-Huei; Mead, Iq; Rigby, Matt; White, Emily

    2015-04-01

    There are a large variety of halocarbons present in the atmosphere that significantly impact on stratospheric ozone depletion and/or global warming. Though the use of some of these compounds has been phased out and replaced under global control measures, relatively long atmospheric lifetimes, imperfect substitutes and incomplete reductions in usage mean that global concentrations of halocarbons still require regular monitoring. This is especially true for the rapidly developing East Asian region, where high emissions have been repeatedly reported in recent years. We here present results from an air sampling activity in Taiwan and Malaysia during the spring months of 2013 and 2014. A large range of halocarbons, including a number of novel gases, were investigated via high sensitivity gas chromatography mass spectrometry (GC-MS). We find periods of relatively clean air as well as episodes that appear to be impacted by urban and/or industrial emissions and examine correlations between individual species. Observed mixing ratios are compared in context with both global background data and other regional studies. Enhancements in the abundances of many halocarbons are detected with examples including the Halons 1211 and 1202 as well as the very long-lived perfluorocarbons c-C4F8, C5F12 and C7F16. We also show and evaluate unusually high mixing ratios of other globally growing halocarbons such as sulphur hexafluoride (SF6), HCFC-133a (CF3CH2Cl), and CFC-113a (CF3CCl3). Finally, we use NAME analysis to produce back-trajectories in order to assess possible regional emission sources.

  20. Control of acid gases using a fluidized bed adsorber.

    PubMed

    Chiang, Bo-Chin; Wey, Ming-Yen; Yeh, Chia-Lin

    2003-08-01

    During incineration, secondary pollutants such as acid gases, organic compounds, heavy metals and particulates are generated. Among these pollutants, the acid gases, including sulfur oxides (SO(x)) and hydrogen chloride (HCl), can cause corrosion of the incinerator piping and can generate acid rain after being emitted to the atmosphere. To address this problem, the present study used a novel combination of air pollution control devices (APCDs), composed of a fluidized bed adsorber integrated with a fabric filter. The major objective of the work is to demonstrate the performance of a fluidized bed adsorber for removal of acid gases from flue gas of an incinerator. The adsorbents added in the fluidized bed adsorber were mainly granular activated carbon (AC; with or without chemical treatment) and with calcium oxide used as an additive. The advantages of a fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of acid gases when using a dry method. On the other hand, because the fluidized bed can filter particles, fine particles prior to and after passing through the fluidized bed adsorber were investigated. The competing adsorption on activated carbon between different characteristics of pollutants was also given preliminary discussion. The results indicate that the removal efficiencies of the investigated acid gases, SO(2) and HCl, are higher than 94 and 87%, respectively. Thus, a fluidized bed adsorber integrated with a fabric filter has the potential to replace conventional APCDs, even when there are other pollutants at the same time.

  1. 1988 Pilot Institute on Global Change on trace gases and the biosphere

    SciTech Connect

    Eddy, J.A.; Moore, B. III

    1998-07-01

    This proposal seeks multi-agency funding to conduct an international, multidisciplinary 1988 Pilot Institute on Global Change to take place from August 7 through 21, 1988, on the topic: Trace Gases and the Biosphere. The institute, to be held in Snowmass, Colorado, is envisioned as a pilot version of a continuing series of institutes on Global Change (IGC). This proposal seeks support for the 1988 pilot institute only. The concept and structure for the continuing series, and the definition of the 1988 pilot institute, were developed at an intensive and multidisciplinary Summer Institute Planning Meeting in Boulder, Colorado, on August 24--25, 1987. The theme for the 1988 PIGC, Trace Gases and the Biosphere, will focus a concerted, high-level multidisciplinary effort on a scientific problem central to the Global Change Program. Dramatic year-to-year increases in the global concentrations of radiatively-active trace gases such as methane and carbon dioxide are now well documented. The predicted climatic effects of these changes lend special urgency to efforts to study the biospheric sources and sinks of these gases and to clarify their interactions and role in the geosphere-biosphere system.

  2. A measurement system for the atmospheric trace gases CH4 and CO

    NASA Technical Reports Server (NTRS)

    Condon, E. P.

    1977-01-01

    A system for measuring ambient clean air levels of the atmospheric trace gases methane and carbon monoxide is described. The analytical method consists of a gas chromatographic technique that incorporates sample preconcentration with catalytic conversion of CO to CH4 and subsequent flame ionization detection of these gases. The system has sufficient sensitivity and repeatability to make the precise measurements required to establish concentration profiles for CO and CH4 in the planetary boundary layer. A discussion of the bottle sampling program being conducted to obtain the samples for the concentration profiles is also presented.

  3. Long-Term Changes of Tropospheric Trace Gases over Pakistan Derived From Multiple Satellite Instruments

    NASA Astrophysics Data System (ADS)

    Zeb, Naila; Fahim Khokhar, Muhammad; Murtaza, Rabbia; Noreen, Asma; Khalid, Tameem

    2016-07-01

    Air pollution is the expected key environmental issue of Pakistan in coming years due to its ongoing rapid economic growth and this trend suggests only worst air quality over time. In 2014, World bank reported the Pakistan's urban air quality among the most severe in the world and intimated the government to make improvement in air quality as a priority policy agenda. In addition it is recommended to strengthen the institutional and technical capacity of organizations responsible for air quality management. Therefore, the study is designed to put efforts in highlighting air quality issues. The study will provide first database for tropospheric trace gases over Pakistan. The study aims to analyse tropospheric concentrations of CO, TOC, NO2 and HCHO over Pakistan using multisensory data from January 2005 to January 2014. Spatio-temporal and seasonal variability of tropospheric trace gases is observed over the decade to explore long term trend. Hotspots are identified to see variation of species with latitude and to highlight possible sources of trace gases over the Pakistan. High concentrations of trace gases are mainly observed over the Punjab region, which may be attributed to its metropolitan importance. It is the major agricultural, industrialized and urbanized (nearly 60% of the Pakistan's population) sector of the country. Overall significant decreasing trend of CO is identified by MOPITT with relative change of 12.4%. Tropospheric ozone column (TOC) showed insignificant increasing trend with temporal increase of 10.4% whereas NO2 exhibited a significant temporal increase of about 28%. For formaldehyde (HCHO), an increase of about 3.8% is calculated for SCIAMACHY data. Well defined seasonal cycles for these trace gases are observed over the whole study period. CO concentrations showed peak in winter months (November/December/January/February) and dip in the months of Summer/Monsoon (June/July/August). In spite of CO, TCO increases gradually in March and peaks

  4. Climate-chemical interactions and effects of changing atmospheric trace gases

    SciTech Connect

    Ramanathan, V.; Callis, L.; Cess, R.; Hansen, J.; Isaksen, I.; Kuhn, W.; Lacis, A.; Luther, F.; Mahlman, J.; Reck, R.; and others

    1987-08-01

    The problem concerning the greenhouse effects of human activities has broadened in scope from the CO2-climate problem to the trace gas-climate problem. The climate effects of non-CO2 trace gases are strongly governed by interactions between chemistry, radiation, and dynamics. We discuss in detail the nature of the trace gas radiative heating and describe the importance of radiative-chemical interactions within the troposphere and the stratosphere. We make an assessment of the trace gas effects on troposphere-stratosphere temperature trends for the period covering the preindustrial era to the present and for the next several decades. Non-CO2 greenhouse gases in the atmosphere are now adding to the greenhouse effect by an amount comparable to the effect of CO2. The rate of decadal increase of the total greenhouse forcing is now 3--6 times greater than the mean rate for the period 1850--1960. Time-dependent calculations with a simplified one-dimensional diffusive ocean model suggest that a surface warming about 0.4--0.8 K should have occurred during 1850 to 1980. For the various trace gas scenarios considered in this study, the equilibrium surface warming for the period 1980 to 2030 ranges from 0.8 to 4.1 K. This wide range in the projected warming is due to the range in the assumed scenario as well as due to the threefold uncertainty in the sensitivity of climate models.

  5. Development of Optical Parametric Amplifier for Lidar Measurements of Trace Gases on Earth and Mars

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephen R.; Krainak, Michael; Abshire, James

    2011-01-01

    Trace gases in planetary atmospheres offer important clues as to the origins of the planet's hydrology, geology. atmosphere. and potential for biology. Wc report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OP A output light is single frequency with high spectral purity and is widely tunable both at 1600 nm and 3300 nm with an optical-optical conversion efficiency of approximately 40%. We demonstrated open-path atmospheric measurements ofCH4 (3291 nm and 1651 nm). CO2 (1573 nm), H20 (1652 nm) with this laser source.

  6. Co-laser photoacoustic spectroscopy of gases and vapours for trace gas analysis

    NASA Astrophysics Data System (ADS)

    Bernegger, S.; Sigrist, M. W.

    This comprehensive study reviews the sensitive and selective detection of trace gases by laser photoacoustic spectroscopy. A computer controlled CO-laser photoacoustic system is presented. The wavelength range between 5.0 and 6.5 μm is of great interest because it coincides with specific absorption bands of various gases and vapours of environmental concern. However, since water-vapour, which is present in most samples, absorbs rather strongly in this wavelength region, its contribution to the total absorption has to be determined with high accuracy. For this purpose, we developed a dual-beam setup with sample- and reference cell. The novel design of these resonant photoacoustic cells is based on a new matrix formalism with distributed acoustic impedances and sources. Our photoacoustic system is calibrated with certified gas mixtures and vapours. In total, the absorption cross sections of 18 gases and vapours have been derived for all CO-laser lines. In addition to the absorption, the relaxation time of vibrationally excited nitric oxide (NO) could be deduced by measuring the phase shift of the photoacoustic signal for a sample of nitrogen containing traces of NO and water-vapour. The main application concerns the detection of multiple components in gas mixtures, particularly in exhaust gases. The high sensitivity achieved permits the detection of trace gases at ppbv concentrations. The problem of interfering absorptions occurring for multicomponent mixtures is studied in detail. We discuss measurements and results on exhausts of various vehicles. The photoacoustic spectra of the exhaust samples are analyzed on the basis of the calibration spectra with the aid of an iterative mathematical procedure. The individual concentrations of 12 of the most important components including nitric oxide, olefines, aromatic hydrocarbons and aldehydes could be derived. In particular, the selective detection of the different isomers of xylene is emphasized.

  7. High sensitivity detection of trace gases at atmospheric pressure using tunable diode lasers

    NASA Technical Reports Server (NTRS)

    Reid, J.; Sinclair, R. L.; Grant, W. B.; Menzies, R. T.

    1985-01-01

    A detailed study of the detection of trace gases at atmospheric pressure using tunable diode lasers is described. The influence of multipass cells, retroreflectors and topographical targets is examined. The minimum detectable infrared absorption ranges from 0.1 percent for a pathlength of 1.2 km to 0.01 percent over short pathlengths. The factors which limit this sensitivity are discussed, and the techniques are illustrated by monitoring atmospehric CO2 and CH4.

  8. Effects of systematic errors on the mixing ratios of trace gases obtained from occulation spectra

    NASA Technical Reports Server (NTRS)

    Shaffer, W. A.; Shaw, J. H.; Farmer, C. B.

    1983-01-01

    The influence of systematic errors in the parameters of the models describing the geometry and the atmosphere on the profiles of trace gases retrieved from simulated solar occultation spectra, collected at satellite altitudes, is investigated. Because of smearing effects and other uncertainties, it may be preferable to calibrate the spectra internally by measuring absorption lines of an atmospheric gas such as CO2 whose vertical distribution is assumed rather than to relay on externally supplied information.

  9. Distributions and Correlations of Organic Trace Gases in the Western Pacific Atmosphere

    NASA Astrophysics Data System (ADS)

    Donets, V.; Atlas, E. L.; Schauffler, S.; Navarro, M. A.; Lueb, R.; Campos, T. L.; Weinheimer, A. J.; Montzka, D.; Kaser, L.; Pan, L.; Salawitch, R. J.; Zhu, X.; Pope, L.

    2014-12-01

    The chemistry of the Tropical Western Pacific atmosphere was studied during three coordinated research missions (CONTRAST, ATTREX, CAST) during Winter, 2014. The purpose of the studies was to examine the chemical emissions of reactive gases from the marine surface, to diagnose transport characteristics of this region, and to better understand the controls of the chemical composition and reactive gas budgets of the tropical atmosphere, including the Tropical Transition Layer (TTL) and lower tropical stratosphere. As part of these studies a wide range of trace gases were measured, including various halo- and hydrocarbons, organic nitrates, methyl halides and solvents. In this presentation we will discuss results from whole air samples that were collected from NASA Global Hawk and NSF/NCAR Gulfstream-V aircrafts during ATTREX and CONTRAST, respectively. Samples were collected at altitudes from near 0.5 km to 18 km, and included latitudes from 40°N to 20°S in the Western Pacific. Combined measurements from two aircrafts produced over 1200 samples, which were subsequently analyzed in the field by means of gas chromatography combined with mass selective, flame ionization and electron capture detectors. The observed distributions of trace gases reflected the combined effects of marine emissions and convective mixing, long range transport, and slow ascent in the TTL. We will show our preliminary results featuring vertical and horizontal distributions of selected hydrocarbon and organic halogen trace species and correlations among these species that were observed during the campaigns.

  10. Measuring OH Reaction Rate Constants and Estimating the Atmospheric Lifetimes of Trace Gases.

    NASA Astrophysics Data System (ADS)

    Orkin, Vladimir; Kurylo, Michael

    2015-04-01

    Reactions with hydroxyl radicals and photolysis are the main processes dictating a compound's residence time in the atmosphere for a majority of trace gases. In case of very short-lived halocarbons their reaction with OH dictates both the atmospheric lifetime and active halogen release. Therefore, the accuracy of OH kinetic data is of primary importance for the comprehensive modeling of a compound's impact on the atmosphere, such as in ozone depletion (i.e., the Ozone Depletion Potential, ODP) and climate change (i.e., the Global Warming Potential, GWP), each of which are dependent on the atmospheric lifetime of the compound. We have demonstrated the ability to conduct very high accuracy determinations of OH reaction rate constants over the temperature range of atmospheric interest, thereby decreasing the uncertainty of kinetic data to 2-3%. The atmospheric lifetime of a well-mixed compound due to its reaction with tropospheric hydroxyl radicals can be estimated by using a simple scaling procedure that is based on the results of field observations of methyl chloroform concentrations and detailed modeling of the OH distribution in the atmosphere. The currently available modeling results of the atmospheric fate of various trace gases allow for an improved understanding of the ability and accuracy of simplified semi-empirical estimations of atmospheric lifetimes. These aspects will be illustrated in this presentation for a variety of atmospheric trace gases.

  11. Measuring OH Reaction Rate Constants and Estimating the Atmospheric Lifetimes of Trace Gases.

    NASA Astrophysics Data System (ADS)

    Orkin, V. L.; Kurylo, M. J., III

    2014-12-01

    Reactions with hydroxyl radicals and photolysis are the main processes dictating a compound's residence time in the atmosphere for a majority of trace gases. In case of very short-lived halocarbons their reaction with OH dictates both the atmospheric lifetime and active halogen release. Therefore, the accuracy of OH kinetic data is of primary importance for the comprehensive modeling of a compound's impact on the atmosphere, such as in ozone depletion (i.e., the Ozone Depletion Potential, ODP) and climate change (i.e., the Global Warming Potential, GWP), each of which are dependent on the atmospheric lifetime of the compound. We have demonstrated the ability to conduct very high accuracy determinations of OH reaction rate constants over the temperature range of atmospheric interest, thereby decreasing the uncertainty of kinetic data to 2-3%. The atmospheric lifetime of a tropospherically well-mixed compound due to its reaction with tropospheric hydroxyl radicals can be estimated by using a simple scaling procedure that is based on the results of field observations of methyl chloroform concentrations and detailed modeling of the OH distribution in the atmosphere. The currently available modeling results of the atmospheric fate of various trace gases allow for an improved understanding of the ability and accuracy of simplified semi-empirical estimations of atmospheric lifetimes. These aspects will be illustrated in this presentation for a variety of atmospheric trace gases.

  12. Mid-Infrared OPO for High Resolution Measurements of Trace Gases in the Mars Atmosphere

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Numata,Kenji; Riris, haris; Abshire, James B.; Allan, Graham; Sun, Xiaoli; Krainak, Michael A.

    2008-01-01

    The Martian atmosphere is composed primarily (>95%) of CO2 and N2 gas, with CO, O2, CH4, and inert gases such as argon comprising most of the remainder. It is surprisingly dynamic with various processes driving changes in the distribution of CO2, dust, haze, clouds and water vapor on global scales in the meteorology of Mars atmosphere [I]. The trace gases and isotopic ratios in the atmosphere offer important but subtle clues as to the origins of the planet's atmosphere, hydrology, geology, and potential for biology. In the search for life on Mars, an important process is the ability of bacteria to metabolize inorganic substrates (H2, CO2 and rock) to derive energy and produce methane as a by-product of anaerobic metabolism. Trace gases have been measured in the Mars atmosphere from Earth, Mars orbit, and from the Mars surface. The concentration of water vapor and various carbon-based trace gases are observed in variable concentrations. Within the past decade multiple groups have reported detection of CH4, with concentrations in the 10's of ppb, using spectroscopic observations from Earth [2]. Passive spectrometers in the mid-infrared (MIR) are restricted to the sunlit side of the planet, generally in the mid latitudes, and have limited spectral and spatial resolution. To accurately map the global distribution and to locate areas of possibly higher concentrations of these gases such as plumes or vents requires an instrument with high sensitivity and fine spatial resolution that also has global coverage and can measure during both day and night. Our development goal is a new MIR lidar capable of measuring, on global scales, with sensitivity, resolution and precision needed to characterize the trace gases and isotopic ratios of the Martian atmosphere. An optical parametric oscillator operating in the MIR is well suited for this instrument. The sufficient wavelength tuning range of the OPO can extend the measurements to other organic molecules, CO2, atmospheric water

  13. Climate-chemical interactions and effects of changing atmospheric trace gases

    NASA Astrophysics Data System (ADS)

    Ramanathan, V.; Callis, L.; Cess, R.; Hansen, J.; Isaksen, I.

    1987-08-01

    The paper considers trace gas-climate effects including the greenhouse effect of polyatomic trace gases, the nature of the radiative-chemical interactions, and radiative-dynamical interactions in the stratosphere, and the role of these effects in governing stratospheric climate change. Special consideration is given to recent developments in the investigations of the role of oceans in governing the transient climate responses, and a time-dependent estimate of the potential trace gas warming from the preindustrial era to the early 21st century. The importance of interacting modeling and observational efforts is emphasized. One of the problems remaining on the observational front is the lack of certainty in current estimates of the rate of growth of CO, O3, and NOx; the primary challenge is the design of a strategy that will minimize the sampling errors.

  14. Climate-chemical interactions and effects of changing atmospheric trace gases

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Callis, L.; Cess, R.; Hansen, J.; Isaksen, I.

    1987-01-01

    The paper considers trace gas-climate effects including the greenhouse effect of polyatomic trace gases, the nature of the radiative-chemical interactions, and radiative-dynamical interactions in the stratosphere, and the role of these effects in governing stratospheric climate change. Special consideration is given to recent developments in the investigations of the role of oceans in governing the transient climate responses, and a time-dependent estimate of the potential trace gas warming from the preindustrial era to the early 21st century. The importance of interacting modeling and observational efforts is emphasized. One of the problems remaining on the observational front is the lack of certainty in current estimates of the rate of growth of CO, O3, and NOx; the primary challenge is the design of a strategy that will minimize the sampling errors.

  15. Metagenomic evidence for metabolism of trace atmospheric gases by high-elevation desert Actinobacteria

    PubMed Central

    Lynch, Ryan C.; Darcy, John L.; Kane, Nolan C.; Nemergut, Diana R.; Schmidt, Steve K.

    2014-01-01

    Previous surveys of very dry Atacama Desert mineral soils have consistently revealed sparse communities of non-photosynthetic microbes. The functional nature of these microorganisms remains debatable given the harshness of the environment and low levels of biomass and diversity. The aim of this study was to gain an understanding of the phylogenetic community structure and metabolic potential of a low-diversity mineral soil metagenome that was collected from a high-elevation Atacama Desert volcano debris field. We pooled DNA extractions from over 15 g of volcanic material, and using whole genome shotgun sequencing, observed only 75–78 total 16S rRNA gene OTUs3%. The phylogenetic structure of this community is significantly under dispersed, with actinobacterial lineages making up 97.9–98.6% of the 16S rRNA genes, suggesting a high degree of environmental selection. Due to this low diversity and uneven community composition, we assembled and analyzed the metabolic pathways of the most abundant genome, a Pseudonocardia sp. (56–72% of total 16S genes). Our assembly and binning efforts yielded almost 4.9 Mb of Pseudonocardia sp. contigs, which accounts for an estimated 99.3% of its non-repetitive genomic content. This genome contains a limited array of carbohydrate catabolic pathways, but encodes for CO2 fixation via the Calvin cycle. The genome also encodes complete pathways for the catabolism of various trace gases (H2, CO and several organic C1 compounds) and the assimilation of ammonia and nitrate. We compared genomic content among related Pseudonocardia spp. and estimated rates of non-synonymous and synonymous nucleic acid substitutions between protein coding homologs. Collectively, these comparative analyses suggest that the community structure and various functional genes have undergone strong selection in the nutrient poor desert mineral soils and high-elevation atmospheric conditions. PMID:25566214

  16. Distribution and Sources of Trace Gases and Aerosols in the Asian Summer Monsoon Anticyclone - Aircraft Observations and Model Simulations

    NASA Astrophysics Data System (ADS)

    Schlager, H.; Klausner, T.; Aufmhoff, H.; Baumann, R.; Gottschaldt, K. D.

    2015-12-01

    We report aircraft observations of trace gases and aerosols from recent field campaigns in the Asian summer monsoon anticyclone. Measurements were performed with the DLR Falcon and HALO aircraft at altitudes up to 15 km across the boundary of the anticyclone over the Arabian Sea during June, July and September conditions. Sharp gradients in chemical tracer mixing ratios were observed at the boundary of the anticyclone. In particular, sulfur dioxide and aerosols were enhanced inside the anticyclone. Ozone and carbon monoxide were enhanced or reduced in the anticyclone depending on the degree of in-mixing of air from the stratosphere inferred from observations of the stratospheric tracer hydrochloric acid. Backward trajectory analysis, tracer dispersion calculations, and simulations with the chemistry-climate model EMAC, nudged to the meteorological conditions of the measurements, were used to investigate the origin and transport of trace gases in and in the vicinity of the anticyclone. A chemistry-aerosol box model was used to simulate the formation of sulfate aerosol from sulfur dioxide inside the anticyclone uplifted by deep convection over northern India and in the Gulf of Bengal.

  17. Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

    NASA Astrophysics Data System (ADS)

    van Leeuwen, T. T.; van der Werf, G. R.

    2010-10-01

    Fires are a major source of trace gases and aerosols to the atmosphere. Quantitative knowledge on biomass burned is improving, most importantly due to new burned area datasets. The partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors (EFs)) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome. In addition, it is unknown whether the measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH4, and CO2, our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different satellite datasets thought to drive part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were less satisfying (rmax=0.62). This may be partly due to uncertainties in the driver datasets, differences in measurement techniques, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of measurements. We derived new mean EFs, using the relative importance of each measurement location with regard to the amount of biomass burned. These weighted averages were within 18% of the arithmetic mean. We argue that from a global modeling perspective, future measurement campaigns could be more beneficial if measurements are made over

  18. Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

    NASA Astrophysics Data System (ADS)

    van Leeuwen, T. T.; van der Werf, G.

    2010-12-01

    Fires are a major source of trace gases and aerosols to the atmosphere. The amount of biomass burned is becoming better known, most importantly due to improved burned area datasets. The partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors [EFs]) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome, and in addition it is unknown whether the measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH4, and CO2, our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different satellite datasets thought to drive part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were less satisfying (r-max=0.62). This may be partly due to uncertainties in the driver datasets, differences in measurement techniques, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of measurement. We derived new mean EFs, using the relative importance of each measurement location. These weighted averages were within 18% of the arithmetic mean. We argue that from a global modeling perspective, future measurement campaigns could be more beneficial if measurements are made over the full fire season, or alternatively

  19. The effects of biomass burning on the concentration of trace gases in the atmosphere

    NASA Technical Reports Server (NTRS)

    Donaldson, Leon M.

    1988-01-01

    Over the past several years, there has been considerable interest concerning the global effects of biomass burning on concentrations of trace gases in the atmosphere. The paucity of reported studies and investigations into the effects of the Greenhouse Gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), up until about a decade ago, would suggest that the topic was not then one of universal concern. Efforts are now being made to understand the biogenic, anthropogenic and photochemical sources of atmospheric trace gases. Biomass burning which includes the burning of forests for clearing, the burning of vegetative stubble after harvesting, and lightning and human-induced wildfires is but one consideration under the general paradigm of atmospheric perturbations. A team of researchers from the Langley Research Center, along with the Canadian Forest Ministry, Ontario, Canada collaborated in an experiment in a deforestration effort through a prescribed burn. Through a specially designed experimental modeling and instrumentation, a substantial pre-burn data set was collected. The primary focus of the pre-burn experimental activities was the emission of nitrous oxide (N2O) gas from selected sites.

  20. Long-lived atmospheric trace gases measurements in flask samples from three stations in India

    NASA Astrophysics Data System (ADS)

    Lin, X.; Indira, N. K.; Ramonet, M.; Delmotte, M.; Ciais, P.; Bhatt, B. C.; Reddy, M. V.; Angchuk, D.; Balakrishnan, S.; Jorphail, S.; Dorjai, T.; Mahey, T. T.; Patnaik, S.; Begum, M.; Brenninkmeijer, C.; Durairaj, S.; Kirubagaran, R.; Schmidt, M.; Swathi, P. S.; Vinithkumar, N. V.; Yver Kwok, C.; Gaur, V. K.

    2015-09-01

    With the rapid growth in population and economic development, emissions of greenhouse gases (GHGs) from the Indian subcontinent have sharply increased during recent decades. However, evaluation of regional fluxes of GHGs and characterization of their spatial and temporal variations by atmospheric inversions remain uncertain due to a sparse regional atmospheric observation network. As a result of an Indo-French collaboration, three new atmospheric stations were established in India at Hanle (HLE), Pondicherry (PON) and Port Blair (PBL), with the objective of monitoring the atmospheric concentrations of GHGs and other trace gases. Here we present the results of the measurements of CO2, CH4, N2O, SF6, CO, and H2 from regular flask sampling at these three stations over the period 2007-2011. For each species, annual means, seasonal cycles and gradients between stations were calculated and related to variations in natural GHG fluxes, anthropogenic emissions, and monsoon circulations. Covariances between species at the synoptic scale were analyzed to investigate the likely source(s) of emissions. The flask measurements of various trace gases at the three stations have the potential to constrain the inversions of fluxes over southern and northeastern India. However, this network of ground stations needs further extension to other parts of India to better constrain the GHG budgets at regional and continental scales.

  1. Five-year flask measurements of long-lived trace gases in India

    NASA Astrophysics Data System (ADS)

    Lin, X.; Indira, N. K.; Ramonet, M.; Delmotte, M.; Ciais, P.; Bhatt, B. C.; Reddy, M. V.; Angchuk, D.; Balakrishnan, S.; Jorphail, S.; Dorjai, T.; Mahey, T. T.; Patnaik, S.; Begum, M.; Brenninkmeijer, C.; Durairaj, S.; Kirubagaran, R.; Schmidt, M.; Swathi, P. S.; Vinithkumar, N. V.; Yver Kwok, C.; Gaur, V. K.

    2015-03-01

    With the rapid growth in population and economic development, emissions of greenhouse gases (GHGs) from the Indian subcontinent have sharply increased during recent decades. However, evaluation of regional fluxes of GHGs and characterization of their spatial and temporal variations by atmospheric inversions remain uncertain due to a sparse regional atmospheric observation network. As a result of Indo-French collaboration, three new atmospheric stations were established in India at Hanle (HLE), Pondicherry (PON) and Port Blair (PBL), with the objective of monitoring the atmospheric concentrations of GHGs and other trace gases. Here we present the results of five-year measurements (2007-2011) of CO2, CH4, N2O, SF6, CO, and H2 from regular flask sampling at these three stations. For each species, annual means, seasonal cycles and gradients between stations were calculated and related to variations in the natural GHG fluxes, anthropogenic emissions, and the monsoon circulations. Covariances between species at the synoptic scale were analyzed to investigate the dominant source(s) of emissions. The flask measurements of various trace gases at the three stations show potential to constrain the inversions of fluxes over Southern and Northeastern India. However, this network of ground stations needs further extension to other parts of India to allow a better understanding of, and constraints on the GHG budgets at regional and continental scales.

  2. Trace water vapor determination in nitrogen and corrosive gases using infrared spectroscopy

    SciTech Connect

    Espinoza, L.H.; Niemczyk, T.M.; Stallard, B.R.; Garcia, M.J.

    1997-06-01

    The generation of particles in gas handling systems as a result of corrosion is a major concern in the microelectronics industry. The corrosion can be caused by the presence of trace quantities of water in corrosive gases such as HCl or HBr. FTIR spectroscopy has been shown to be a method that can be made compatible with corrosive gases and is capable of detecting low ppb levels of water vapor. In this report, the application of FTIR spectroscopy combined with classical least squares multivariate calibration to detect trace H{sub 2}O in N{sub 2}, HCl and HBr is discussed. Chapter 2 discusses the gas handling system and instrumentation required to handle corrosive gases. A method of generating a background spectrum useful to the measurements discussed in this report, as well as in other application areas such as gas phase environmental monitoring, is discussed in Chapter 3. Experimental results obtained with the first system are presented in Chapter 4. Those results made it possible to optimize the design options for the construction of a dedicate system for low ppb water vapor determination. These designs options are discussed in Chapter 5. An FTIR prototype accessory was built. In addition, a commercially available evacuable FTIR system was obtained for evaluation. Test results obtained with both systems are discussed in Chapter 6. Experiments dealing with the interaction between H{sub 2}O-HCl and potential improvements to the detection system are discussed in Chapter 7.

  3. Tracing a past thermal event by using atmospheric noble gases dissolved in deep Michigan Basin brines

    NASA Astrophysics Data System (ADS)

    Ma, L.; Castro, M. C.; Hall, C. M.

    2008-12-01

    Atmospheric noble gases (e.g., 22Ne, 36Ar, 84Kr, 130Xe) are introduced into the subsurface by recharge water in solubility equilibrium with the atmosphere (Air Saturated Water - ASW). Because noble gases are chemically inert and stable in nature, they are only sensitive to subsurface physical processes. More specifically, depletion of this component in sedimentary systems commonly suggests loss to an oil or natural gas phase in the subsurface, which is originally free of atmospheric noble gases. This has been traditionally used to identify and quantify subsurface oil, gas, and water phase interactions. Alternatively, depletion of atmospheric noble gases due to subsurface boiling and steam phase separation has also been previously recorded in tectonically active areas (hydrothermal systems). Such depletion is thus indicative of the occurrence of a thermal event and can be used to trace the thermal history of stable tectonic regions. Here, we present noble gas concentrations of 38 deep brines (~0.5-3.6km) from the Michigan Basin. The atmospheric noble gas component shows a strong depletion pattern with respect to air saturated water. Depletion of lighter gases (22Ne and 36Ar) is stronger compared to the heavier ones (84Kr and 130Xe). To understand the mechanisms responsible for this overall atmospheric noble gas depletion, phase interaction models were tested. We show that this atmospheric noble gas depletion pattern is best explained by a model involving subsurface boiling and steam separation, and thus, consistent with the occurrence of a past thermal event of mantle origin as previously indicated by both high 4He/heat flux ratios and the presence of primordial mantle He and Ne signatures in the basin. Such a conceptual model is also consistent with the presence of past elevated temperatures in the Michigan Basin (e.g., ~80- 260°C) at shallow depths as suggested by previous thermal studies in the basin. We suggest that recent reactivation of the ancient mid

  4. An investigation of the sub-grid variability of trace gases and aerosols for global climate modeling

    SciTech Connect

    Qian, Yun; Gustafson, William I.; Fast, Jerome D.

    2010-07-29

    One fundamental property and limitation of grid based models is their inability to identify spatial details smaller than the grid cell size. While decades of work have gone into developing sub-grid treatments for clouds and land surface processes in climate models, the quantitative understanding of sub-grid processes and variability for aerosols and their precursors is much poorer. In this study, WRF-Chem is used to simulate the trace gases and aerosols over central Mexico during the 2006 MILAGRO field campaign, with multiple spatial resolutions and emission/terrain scenarios. Our analysis focuses on quantifying the sub-grid variability (SGV) of trace gases and aerosols within a typical global climate model grid cell, i.e. 75x75 km2. Our results suggest that a simulation with 3-km horizontal grid spacing adequately reproduces the overall transport and mixing of trace gases and aerosols downwind of Mexico City, while 75-km horizontal grid spacing is insufficient to represent local emission and terrain-induced flows along the mountain ridge, subsequently affecting the transport and mixing of plumes from nearby sources. Therefore, the coarse model grid cell average may not correctly represent aerosol properties measured over polluted areas. Probability density functions (PDFs) for trace gases and aerosols show that secondary trace gases and aerosols, such as O3, sulfate, ammonium, and nitrate, are more likely to have a relatively uniform probability distribution (i.e. smaller SGV) over a narrow range of concentration values. Mostly inert and long-lived trace gases and aerosols, such as CO and BC, are more likely to have broad and skewed distributions (i.e. larger SGV) over polluted regions. Over remote areas, all trace gases and aerosols are more uniformly distributed compared to polluted areas. Both CO and O3 SGV vertical profiles are nearly constant within the PBL during daytime, indicating that trace gases are very efficiently transported and mixed vertically by

  5. An overview of current issues in the uptake of atmospheric trace gases by aerosols and clouds

    NASA Astrophysics Data System (ADS)

    Kolb, C. E.; Cox, R. A.; Abbatt, J. P. D.; Ammann, M.; Davis, E. J.; Donaldson, D. J.; Garrett, B. C.; George, C.; Griffiths, P. T.; Hanson, D. R.; Kulmala, M.; McFiggans, G.; Pöschl, U.; Riipinen, I.; Rossi, M. J.; Rudich, Y.; Wagner, P. E.; Winkler, P. M.; Worsnop, D. R.; O'Dowd, C. D.

    2010-11-01

    A workshop was held in the framework of the ACCENT (Atmospheric Composition Change - a European Network) Joint Research Programme on "Aerosols" and the Programme on "Access to Laboratory Data". The aim of the workshop was to hold "Gordon Conference" type discussion covering accommodation and reactive uptake of water vapour and trace pollutant gases on condensed phase atmospheric materials. The scope was to review and define the current state of knowledge of accommodation coefficients for water vapour on water droplet and ice surfaces, and uptake of trace gas species on a variety of different surfaces characteristic of the atmospheric condensed phase particulate matter and cloud droplets. Twenty-six scientists participated in this meeting through presentations, discussions and the development of a consensus review. In this review we present an analysis of the state of knowledge on the thermal and mass accommodation coefficient for water vapour on aqueous droplets and ice and a survey of current state-of the-art of reactive uptake of trace gases on a range of liquid and solid atmospheric droplets and particles. The review recommends consistent definitions of the various parameters that are needed for quantitative representation of the range of gas/condensed surface kinetic processes important for the atmosphere and identifies topics that require additional research.

  6. Analysis of Process Gases and Trace Contaminants in Membrane-Aerated Gaseous Effluent Streams.

    NASA Technical Reports Server (NTRS)

    Coutts, Janelle L.; Lunn, Griffin Michael; Meyer, Caitlin E.

    2015-01-01

    In membrane-aerated biofilm reactors (MABRs), hollow fibers are used to supply oxygen to the biofilms and bulk fluid. A pressure and concentration gradient between the inner volume of the fibers and the reactor reservoir drives oxygen mass transport across the fibers toward the bulk solution, providing the fiber-adhered biofilm with oxygen. Conversely, bacterial metabolic gases from the bulk liquid, as well as from the biofilm, move opposite to the flow of oxygen, entering the hollow fiber and out of the reactor. Metabolic gases are excellent indicators of biofilm vitality, and can aid in microbial identification. Certain gases can be indicative of system perturbations and control anomalies, or potentially unwanted biological processes occurring within the reactor. In confined environments, such as those found during spaceflight, it is important to understand what compounds are being stripped from the reactor and potentially released into the crew cabin to determine the appropriateness or the requirement for additional mitigation factors. Reactor effluent gas analysis focused on samples provided from Kennedy Space Center's sub-scale MABRs, as well as Johnson Space Center's full-scale MABRs, using infrared spectroscopy and gas chromatography techniques. Process gases, such as carbon dioxide, oxygen, nitrogen, nitrogen dioxide, and nitrous oxide, were quantified to monitor reactor operations. Solid Phase Microextraction (SPME) GC-MS analysis was used to identify trace volatile compounds. Compounds of interest were subsequently quantified. Reactor supply air was examined to establish target compound baseline concentrations. Concentration levels were compared to average ISS concentration values and/or Spacecraft Maximum Allowable Concentration (SMAC) levels where appropriate. Based on a review of to-date results, current trace contaminant control systems (TCCS) currently on board the ISS should be able to handle the added load from bioreactor systems without the need

  7. The temporal and spatial variability of halogenated trace gases in the upper troposphere.

    NASA Astrophysics Data System (ADS)

    Oram, D.; O'Sullivan, D.; Brenninkmeijer, C.; van Velthoven, P.; Sturges, W.

    2007-12-01

    Halogenated trace gases play an important role in stratospheric and tropospheric chemistry, particularly affecting ozone concentrations. In addition they have direct and indirect effects on radiative forcing, and impact on tropospheric reactivity. Data from the CARIBIC project (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrumented Container) have been used in conjunction with back-trajectory analysis to further our understanding of the chemical composition, inter-hemispheric distribution and source regions of halogenated compounds in the upper troposphere and lower stratosphere. Whole air samples collected within CARIBIC, have been analyzed using gas chromatography mass spectrometry for around 35 halocarbons and related trace gases, among them many potent greenhouse gases and species important for ozone depletion. The large spatial and temporal coverage of the CARIBIC project has enabled new work to be done investigating recent inter-annual trends in the CFCs, halons, and other anthropogenic halocarbons, as well as identifying clear inter-hemispheric and seasonal variability for a number of species, such as methylene chloride, HCFCs, methyl chloride, methyl bromide, methyl iodide and several reactive short lived bromo and chloro carbons. In this paper results from the CARIBIC flights to China and the Philippines will be highlighted, to discuss anthropogenic emissions of ozone depleting and greenhouse gases, from Asia and Africa. Data from flights to South America will also be presented. As production and consumption of many of these substances are being phased out in Europe and North America, emissions from Asia, Africa and also South America are becoming increasingly more important. Emissions from these regions are also of interest, as the most significant sources are often collocated with regions of convection in the tropics and sub-tropics. Thus enabling a greater proportion of the substances emitted to reach the stratosphere, where

  8. Monitoring shipping emissions with MAX-DOAS measurements of reactive trace gases

    NASA Astrophysics Data System (ADS)

    Wittrock, Folkard; Peters, Enno; Seyler, André; Kattner, Lisa; Mathieu-Üffing, Barbara; Burrows, John P.; Chirkov, Maksym; Meier, Andreas C.; Richter, Andreas; Schönhardt, Anja; Schmolke, Stefan; Theobald, Norbert

    2014-05-01

    Air pollution from ships contributes to overall air quality problems and it has direct health effects on the population in particular in coastal regions, and in harbor cities. In order to reduce the emissions the International Maritime Organisation (IMO) have tightened the regulations for air pollution. E.g. Sulfur Emission Control Areas (SECA) have been introduced where the sulfur content of marine fuel is limited. However, up to now there is no regular monitoring system available to verify that ships are complying with the new regulations. Furthermore measurements of reactive trace gases in marine environments are in general sparse. The project MeSMarT (Measurements of shipping emissions in the marine troposphere, www.mesmart.de) has been established as a cooperation between the University of Bremen and the German Bundesamt für Seeschifffahrt und Hydrographie (Federal Maritime and Hydrographic Agency) with support of the Helmholtz Research Centre Geesthacht to estimate the influence of ship emissions on the chemistry of the atmospheric boundary layer and to establish a monitoring system for main shipping routes. Here we present MAX-DOAS observations of NO2 and SO2 carried out during ship campaigns in the North and Baltic Sea and from two permanent sites close to the Elbe river (Wedel, Germany) and on the island Neuwerk close to the mouths of Elbe and Weser river. Mixing ratios of both trace gases have been retrieved using different approaches (pure geometric and taking into account the radiative transfer) and compared to in situ and air borne observations (see Kattner et al., Monitoring shipping emissions with in-situ measurements of trace gases, and Meier et al., Airborne measurements of NO2 shipping emissions using imaging DOAS) observations. Furthermore simple approaches have been used to calculate emission factors of NOx and SO2 for single ships.

  9. Method and apparatus for detecting and measuring trace impurities in flowing gases

    DOEpatents

    Taylor, Gene W.; Dowdy, Edward J.

    1979-01-01

    Trace impurities in flowing gases may be detected and measured by a dynamic atomic molecular emission spectrograph utilizing as its energy source the energy transfer reactions of metastable species, atomic or molecular, with the impurities in the flowing gas. An electronically metastable species which maintains a stable afterglow is formed and mixed with the flowing gas in a region downstream from and separate from the region in which the metastable species is formed. Impurity levels are determined quantitatively by the measurement of line and/or band intensity as a function of concentration employing emission spectroscopic techniques.

  10. Acetone in the upper troposphere and lower stratosphere: Impact on trace gases and aerosols

    NASA Astrophysics Data System (ADS)

    Arnold, F.; Bürger, V.; Droste-Fanke, B.; Grimm, F.; Krieger, A.; Schneider, J.; Stilp, T.

    Upper tropospheric and lower stratospheric acetone measurements have been performed in summer and winter 1994 through 1996 at latitudes between 30°N and 75°N using ion-molecule reaction mass spectrometry. We observed very high acetone volume mixing ratios of up to 3000 pptv (parts per trillion by volume) in extended air masses and in summer when acetone destruction by photodissociation is fast. This indicates efficient transport of acetone and photochemical acetone precursors to the upper troposphere and efficient upper tropospheric formation of acetone products, especially HOx radicals and PAN. Our data indicate large HOx production from acetone which has important implications for other trace gases and aerosols.

  11. Seasonal variation of the temporal variance of long-lived trace gases measured during MAP

    NASA Technical Reports Server (NTRS)

    Roeth, E. P.; Schmidt, U.

    1989-01-01

    A series of balloon observations of long lived trace gases was performed in the midlatitude stratosphere during MAP. The temporal variance of the local mixing ratios of CH4, N2O, CFCl3, and CF2Cl2 indicates a substantial annual variability. The concept of the equivalent displacement height (EDH), introduced by Ehhalt et al., is used to investigate some features of transport activity in the lower stratosphere. It appears that most of the temporal variance originates from strong transport effects during the periods of the spring and autumn turn-around of the stratospheric circulation. The dynamical process was found to be considerably reduced during October.

  12. Detectability of trace gases in the Martian atmosphere using gas correlation filter radiometry

    NASA Astrophysics Data System (ADS)

    Sinclair, J.; Irwin, P. G. J.; Wilson, E.; Calcutt, S.

    2015-10-01

    We present the results of radiative transfer simulations of a gas correlation filter radiometer (GCFR) in the detection of trace species in the Martian atmosphere. We investigated two scenarios: 1) nadir and/or limb sounding from a Mars orbiter in the thermal infrared, 2) solar occultation measurements in the near-infrared from the Martian surface. In both scenarios, a GCFR would allow detection of trace gases at a lower concentration than that detectable by a conventional filter radiometer. In nadir/limb sounding, we find that CH4, SO2, N2O, C2H2 and CH3OH are detectable at concentrations lower than previously-derived upper limits. From solar occultation measurements, we find that CH4, SO2, C2H2, C2H6 are detectable at concentrations lower than previously-derived upper limits but only in low dust conditions.

  13. Wet precipitation scavenging of soluble atmospheric trace gases due to chemical absorption in inhomogeneous atmosphere

    NASA Astrophysics Data System (ADS)

    Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

    2016-04-01

    We analyze the effects of irreversible chemical reactions of the first and higher orders and aqueous-phase dissociation reactions on the rate of trace gas scavenging by rain in the atmosphere with non-uniform concentration and temperature. We employ an one-dimensional model of precipitation scavenging of chemically active soluble gaseous pollutants that is valid for small gradients of temperature and concentration in the atmosphere. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the partial hyperbolic differential equation of the first order. Scavenging coefficients are calculated for wet removal of chlorine, nitrogen dioxide and sulfur dioxide for the exponential and linear initial altitudinal distributions of trace gases concentration in the atmosphere and linear and uniform altitudinal temperature distributions. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for sulfur dioxide are in a good agreement with the available atmospheric measurements.

  14. Measurement of stratospheric trace gases by millimeter-wave spectroscopy for an annual cycle at the South Pole

    SciTech Connect

    De Zafra, R.L.; Trimble, C.; Reeves, M.

    1994-12-31

    Chemistry and transport processes in the south polar stratosphere have been intensively studied since discovery of the seasonal {open_quotes}ozone hole{close_quotes} appearing over Antarctica. Nevertheless, large gaps still exist in our knowledge of the dynamical and chemical behavior of the polar winter vortex. This behavior is responsible for much of the prior processing of air, and the processing makes possible the formation of a springtime ozone hole. The work described here was intended to fill some of these gaps by frequently monitoring the behavior of several trace gases over as much of a full year cycle as possible, from a central position within the annually forming winter vortex region. The species covered (not all for the full duration of the observations) were ozone, nitrogen dioxide, nitrous oxide, nitric acid, and chlorine monoxide. An upper limit for hydrogen peroxide was also determined by an unsuccessful attempt to detect it. 7 refs.

  15. Simulations of greenhouse trace gases using the Los Alamos chemical tracer model

    SciTech Connect

    Kao, C.Y.J.; Morz, E. ); Tie, X. )

    1991-11-01

    Through three-dimensional global model studies on atmospheric composition and transport, we are improving our quantitative understanding of the origins and behavior of trace gases that affect Earth's radiative energy balance and climate. We will focus, in this paper, on the simulations of three individual trace gases including CFC-11, methyl chloroform, and methane. We first used our chemical tracer model to study the global distribution and trend of chemically inert CFC-11 observed by the Atmospheric Lifetime Experiment. The results show that the model has the ability to reproduce the time-series of the observations. The purpose of this CFC-11 simulation was to test the transport of the model. We then used to model introduce methyl chloroform into the atmosphere according to the known emission patterns and iteratively varied OH fields so that the observed concentrations of methyl chloroform from the observations could be simulated well. The rationale behind this approach is that the reaction with OH is the dominant sink for metyl chloroform and the transport of the model has been tested in the previous CFC-11 study. Finally, using the inferred OH distributions, we conducted a steady-state simulation to reproduce the current methane distribution. The general agreement between the modeled an observed methane surface concentrations has laid a foundation for the simulation of the transient increase of methane.

  16. Simulations of greenhouse trace gases using the Los Alamos chemical tracer model

    SciTech Connect

    Kao, C.Y.J.; Morz, E.; Tie, X.

    1991-11-01

    Through three-dimensional global model studies on atmospheric composition and transport, we are improving our quantitative understanding of the origins and behavior of trace gases that affect Earth`s radiative energy balance and climate. We will focus, in this paper, on the simulations of three individual trace gases including CFC-11, methyl chloroform, and methane. We first used our chemical tracer model to study the global distribution and trend of chemically inert CFC-11 observed by the Atmospheric Lifetime Experiment. The results show that the model has the ability to reproduce the time-series of the observations. The purpose of this CFC-11 simulation was to test the transport of the model. We then used to model introduce methyl chloroform into the atmosphere according to the known emission patterns and iteratively varied OH fields so that the observed concentrations of methyl chloroform from the observations could be simulated well. The rationale behind this approach is that the reaction with OH is the dominant sink for metyl chloroform and the transport of the model has been tested in the previous CFC-11 study. Finally, using the inferred OH distributions, we conducted a steady-state simulation to reproduce the current methane distribution. The general agreement between the modeled an observed methane surface concentrations has laid a foundation for the simulation of the transient increase of methane.

  17. MAX-DOAS measurements of atmospheric trace gases in Ny-Ålesund

    NASA Astrophysics Data System (ADS)

    Wittrock, F.; Oetjen, H.; Richter, A.; Fietkau, S.; Medeke, T.; Rozanov, A.; Burrows, J. P.

    2003-12-01

    A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have been applied to this standard setup to use different lines of sight near to the horizon as additional light sources (MAX - multi axis). Results from measurements at Ny-Ålesund (79° N, 12° E) are presented and interpreted with the full-spherical radiation transport model SCIATRAN. In particular, measurements of the oxygen dimer O4 which has a known column and vertical distribution in the atmosphere are used to evaluate the sensitivity of the retrieval to parameters such as multiple scattering, solar azimuth, surface albedo and refraction in the atmosphere and also to validate the radiative transport model. As a first application, measurements of NO2 emissions from a ship lying in Ny-Ålesund harbour are presented. The results of this study demonstrate the feasibility of long term UV/vis multi axis measurement that can be used to derive not only column amounts of different trace gases but also some information on the vertical location of these absorbers.

  18. Assessment of a 2016 Mission Concept: The Search for Trace Gases in the Atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Zurek, Richard W.; Chicarro, Augustin; Allen, Mark A.; Bertauz, Jean-Loup; Clancy, R. Todd; Daerden, Frank; Formisano, Vittorio; Garvin, James B.; neukum, Gerhard; Smith, Michael D.

    2011-01-01

    The reported detection of methane in the atmosphere of Mars as well as its potentially large seasonal spatial variations challenge our understanding of both the sources and sinks of atmospheric trace gases. The presence of methane suggests ongoing exchange between the subsurface and the atmosphere of potentially biogenic trace gases, while the spatial and temporal variations cannot be accounted for with current knowledge of martian photochemistry. A Joint Instrument Definition Team (JIDT) was asked to assess concepts for a mission that might follow up on these discoveries within the framework of a series of joint missions being considered by ESA and NASA for possible future exploration of Mars. The following is based on the report of the JIDT to the space agencies (Zurek et al., 2009); a synopsis of the report was presented at the Workshop on Mars Methane held in Frascati, Italy, in November 2009. To summarize, the JIDT believed that a scientifically exciting and credible mission could be conducted within the evolving capabilities of the science/telecommunications orbiter being considered by ESA and NASA for possible launch in the 2016 opportunity for Mars.

  19. Quantum cascade laser open-path system for remote sensing of trace gases in Beijing, China

    NASA Astrophysics Data System (ADS)

    Michel, Anna P. M.; Liu, Peter Q.; Yeung, June K.; Corrigan, Paul; Baeck, Mary Lynn; Wang, Zifa; Day, Timothy; Smith, James A.

    2010-11-01

    Exploiting several key characteristics of quantum cascade (QC) lasers, including wide tunability and room-temperature operation, the Quantum Cascade Laser Open-Path System (QCLOPS) was designed for the detection of a range of trace gases and for field deployment in urban environments. Tunability over a wavelength range from 9.3 to 9.8 μm potentially provides the capability for monitoring ozone, ammonia, and carbon dioxide, a suite of trace gases important for air quality and regional climate applications in urban environments. The 2008 Olympic Games in Beijing, China drew attention to air quality problems in urban environments. Prior to and during the Olympic games, regional air quality modifications through factory shutdowns, car restrictions, and construction halts in Beijing and its surrounding areas created a unique test bed for new sensor technologies such as the QCLOPS sensor. We report the design of this novel, open-path air quality sensor and the results of both laboratory tests and field trials during the 2008 Olympic Games in Beijing, China.

  20. Airborne Measurements of Trace Gases and Aerosols in Northern China: EAST-AIRE IOP 2005

    NASA Astrophysics Data System (ADS)

    Li, C.; Dickerson, R. R.; Li, Z.; Stehr, J. W.; Chen, H.; Marufu, L. T.

    2005-12-01

    To characterize the emission, transport and removal of pollutants and aerosols emitted from East Asia, a US-China joint field campaign was conducted from February to April in China under the EAST-AIRE project. Surface and airborne measurements of trace gases and aerosols were made at different locations in northern China. In early April, eight research flights were conducted around Shenyang, an industrialized city with a population of about 6 million, 600 km northeast of Beijing. Parameters measured include SO2, CO, O3, aerosol size distribution, aerosol scattering and absorption coefficients. During 4 of the 8 flights, the research aircraft made spirals over two suburban locations (~50 km south and north of the downtown area of Shenyang) to determine the detailed vertical distribution of trace gases and aerosols. Various weather patterns were encountered, allowing an examination of the roles of atmospheric circulation in transporting local pollutants to much larger areas. For example, the flights made ahead of the cold front showed fairly high concentrations of pollutants above the planetary boundary layer, probably lifted by the upward motion associated with the approaching cold fronts. On the other hand, much lower pollutant levels were found for the flights made behind the cold front. Also observed in one cold-sector flight is a level (~3000 m) with enhanced aerosol scattering but almost undetectable SO2. Back trajectory analysis using NOAA-HYSPLIT model suggests possible dust transport from source regions.

  1. Arctic haze: Patterns and relationships to regional signatures of trace gases

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    We took measurements of up to 30 gases in Arctic haze and in clean Arctic air. These data were obtained from some 500 flask samples taken on three expeditions of the Arctic Gas and Aerosol Sampling Program (AGASP 1, 2, and 3) during the spring of 1983, 1986, and 1989. Concentrations of many gases are significantly higher in the haze layers compared to outside the haze. To look for the possible origins of the haze, we used cluster analysis to derive regional signatures of trace gases at ground-based sites in middle and high northern latitudes. Comparison of the regional signatures with concentrations observed in Arctic haze suggest that there are no significant contributions from North America but possible influences from Russia and eastern Europe. These conclusions complement results derived from the analysis of the Arctic aerosol chemistry. It is possible, however, that Arctic haze originates from the military, industrial, and mining activities within the Arctic circle, particularly from the Russian Koala peninsula.

  2. Clostridium strain which produces acetic acid from waste gases

    DOEpatents

    Gaddy, J.L.

    1997-01-14

    A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 4 figs.

  3. Clostridium stain which produces acetic acid from waste gases

    DOEpatents

    Gaddy, James L.

    1997-01-01

    A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

  4. Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

    NASA Astrophysics Data System (ADS)

    van Leeuwen, T. T.; van der Werf, G. R.

    2011-04-01

    Fires are a major source of trace gases and aerosols to the atmosphere. The amount of biomass burned is becoming better known, most importantly due to improved burned area datasets and a better representation of fuel consumption. The spatial and temporal variability in the partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors (EFs)) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome. In addition, it is unknown whether the available field measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH4, and CO2, our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different measurements of environmental variables that may correlate with part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were lower and explained about 33%, 38%, 19%, and 34% of the variability for respectively CO, CH4, CO2, and the Modified Combustion Efficiency (MCE). This may be partly due to uncertainties in the environmental variables, differences in measurement techniques for EFs, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of EF measurements. We derived new mean EFs, using the relative importance of

  5. Evolution of trace gases and particles emitted by a chaparral fire in California

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Craven, J. S.; Taylor, J. W.; McMeeking, G. R.; Yokelson, R. J.; Burling, I. R.; Urbanski, S. P.; Wold, C. E.; Seinfeld, J. H.; Coe, H.; Alvarado, M. J.; Weise, D. R.

    2011-08-01

    Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 ha prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured post-emission chemical changes in the isolated downwind plume for ~4 h of smoke aging. The measurements were carried out on board a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO2; CO; NOx; NH3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O3 to excess CO in the plume (ΔO3/ΔCO) increased from -0.005 to 0.102 in 4.5 h. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.7 ± 0.4 and 7.3 ± 3.0 (respectively) over the same aging period. Based on the rapid decay of C2H4 we infer an in-plume average OH concentration of 5.3 (±1.0) × 106 molecules cm-3, consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased with plume aging. The observed ammonium increase was a factor of 3.9 ± 2.6 in about 4 h, but accounted for just ~36 % of the gaseous ammonia lost on a molar basis. Some of the gas phase NH3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NOx was converted to PAN and particle nitrate with PAN production being

  6. Evolution of trace gases and particles emitted by a chaparral fire in California

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Craven, J. S.; Taylor, J. W.; McMeeking, G. R.; Yokelson, R. J.; Burling, I. R.; Urbanski, S. P.; Wold, C. E.; Seinfeld, J. H.; Coe, H.; Alvarado, M. J.; Weise, D. R.

    2012-02-01

    Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 hectare prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured physical and chemical changes that occurred in the isolated downwind plume in the first ~4 h after emission. The measurements were carried out onboard a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO2; CO; NOx; NH3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O3 to excess CO in the plume (ΔO3/ΔCO) increased from -5.13 (±1.13) × 10-3 to 10.2 (±2.16) × 10-2 in ~4.5 h following smoke emission. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.73 ± 0.43 and 7.34 ± 3.03 (respectively) over the same time since emission. Based on the rapid decay of C2H4 we infer an in-plume average OH concentration of 5.27 (±0.97) × 106 molec cm-3, consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased over the course of 4 h. The observed ammonium increase was a factor of 3.90 ± 2.93 in about 4 h, but accounted for just ~36% of the gaseous ammonia lost on a molar basis. Some of the gas phase NH3 loss may have been due to condensation on, or formation of, particles

  7. Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid

    DOEpatents

    Chang, Shih-Ger; Liu, David K.

    1992-01-01

    Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

  8. Environmental factors controlling transient and seasonal changes of trace gases within shallow vadose zone

    NASA Astrophysics Data System (ADS)

    Pla, Concepcion; Galiana-Merino, Juan Jose; Cuezva, Soledad; Fernandez-Cortes, Angel; Garcia-Anton, Elena; Cuevas, Jaime; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio; Benavente, David

    2014-05-01

    Shallow vadose environments below soil, mainly caves, show significant seasonal and even daily variations in gas composition of ground air, which involves the exchange of large amounts of gases, e.g. greenhouse gases (GHGs) as CO2 or CH4, with the lower troposphere. To understand better the role of caves as a sink or depot of GHGs, geochemical tracing of air (atmosphere, soil and ground air) was performed at Rull cave (southeast Spain) by monitoring CH4, CO2 and the stable carbon isotopic delta13C[CO2] using cavity ring-down spectroscopy (CRDS). A comprehensive microclimatic monitoring of exterior and cave atmosphere was simultaneously conducted to GHGs-tracking, including factors as temperature, barometric pressure, relative humidity and concentration of CO2 and 222Rn. The analysis of the measured data allows understanding outgassing and isolation processes taking place in the karst cavity. Annual patterns of gases behaviour can be distinguished, depending on the prevailing relationship between outer atmosphere, indoor atmosphere and soil system. Cave air temperature fluctuates around 15.7 ºC and relative humidity remains higher than 96% the whole annual cycle. The mean concentration of 222Rn is 1584 Bq m-3 while CO2 remains 1921 ppm. When external temperature is higher of indoor temperature (April-October), the highest levels of both trace gases are reached, while levels drop to its lowest values in the coldest months. Preliminary results obtained show an annual variation in concentration of CO2 inside the cave between 3300 ppm and 900 ppm, whereas corresponding isotopic signal delta13CO2 varies between -24‰ and -21‰. The results have been studied by Keeling model that approximates the isotopic signal of the source contribution in a resulting air mix. The values registered inside the cave were represented joined to results for exterior air (average values round 410 ppm of CO2 and -9 ‰ for delta13C). Value obtained is -27‰ pointing to a high influence of

  9. Spatial Variability of Trace Gases During DISCOVER-AQ: Planning for Geostationary Observations of Atmospheric Composition

    NASA Technical Reports Server (NTRS)

    Follette-Cook, Melanie B.; Pickering, K.; Crawford, J.; Appel, W.; Diskin, G.; Fried, A.; Loughner, C.; Pfister, G.; Weinheimer, A.

    2015-01-01

    Results from an in-depth analysis of trace gas variability in MD indicated that the variability in this region was large enough to be observable by a TEMPO-like instrument. The variability observed in MD is relatively similar to the other three campaigns with a few exceptions: CO variability in CA was much higher than in the other regions; HCHO variability in CA and CO was much lower; MD showed the lowest variability in NO2All model simulations do a reasonable job simulating O3 variability. For CO, the CACO simulations largely under over estimate the variability in the observations. The variability in HCHO is underestimated for every campaign. NO2 variability is slightly overestimated in MD, more so in CO. The TX simulation underestimates the variability in each trace gas. This is most likely due to missing emissions sources (C. Loughner, manuscript in preparation).Future Work: Where reasonable, we will use these model outputs to further explore the resolvability from space of these key trace gases using analyses of tropospheric column amounts relative to satellite precision requirements, similar to Follette-Cook et al. (2015).

  10. Trace Gases and Aerosols Simulated Over the Indian Domain: Evaluation of the Model Wrf-Chem

    NASA Astrophysics Data System (ADS)

    Michael, M.; Yadav, A.; Tripathi, S. N.; Venkataraman, C.; Kanawade, V. P.

    2012-12-01

    As the anthropogenic emissions from the Asian countries contribute substantially to the global aerosol loading, the study of the distribution of trace gases and aerosols over this region has received increasing attention in recent years. In the present work, the aerosol properties over the Indian domain during the pre-monsoon season has been addressed. The "online" meteorological and chemical transport Weather Research and Forecasting-Chemistry (WRF-Chem) model has been implemented over Indian subcontinent for three consecutive summers in 2008, 2009 and 2010.The initial and boundary conditions are obtained from NCAR reanalysis data. The global emission inventories (REanalysis of the TROpospheric chemical composition (RETRO) and Emissions Database for Global Atmospheric Research (EDGAR)) have been used and are projected for the period of study using the method provided in Ohara et al. (2007). The emission rates of sulfur dioxide, black carbon, organic carbon and PM2.5 available in the global inventory are replaced with the high resolution emission inventory developed over India for the present study. The model simulates meteorological parameters, trace gases and particulate matter. Simulated mixing ratios of trace gases (Ozone, carbon monoxide, nitrogen oxides, and SO2) are compared with ground based as well as satellite observations over India with specific focus on Indo-Gangetic Plain. Simulated aerosol optical depth are in good agreement with those observed by Aerosol Robotic Network (AERONET). The vertical profiles of extinction coefficient have been compared with the Micro Pulse Lidar Network (MPLnet) data. The simulated mass concentration of BC shows very good agreement with those observed at a few ground stations. The vertical profiles of BC have also been compared with aircraft observations carried out during summer of 2008 and 2009, resulting in good agreement. This study shows that WRF-Chem model captures many important features of the observations and

  11. Column amounts of trace gases from ground based FTIR measurements in the late north polar winters 1990 and 1991

    NASA Technical Reports Server (NTRS)

    Adrian, Gabriele; Blumenstock, Thomas; Fischer, Herbert; Frank, Eckard; Gerhardt, Lothar; Gulde, Thomas; Maucher, Guido; Oelhaf, Hermann; Thomas, Peter; Trieschmann, Olaf

    1994-01-01

    Two FTIR spectrometers were employed in the late winters 1990 and 1991 in Esrange, North Sweden, and in Ny Aalesund, Spitsbergen to detect zenith column amounts of several trace gases. Time series of column amounts of the trace gases O3, N2O, CH4, HNO3, NO2, CHl, and HF have been derived from the measured spectra. Additionally, some information on the vertical distribution of HCl could be obtained by analyzing the spectral line shapes. The results are interpreted in terms of dynamical and chemical processes.

  12. Measurements of Long-Lived Trace Gases from Commercial Aircraft Platforms: Development of Instrumentation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The upper troposphere (6-12 km altitude) is a poorly understood and highly vulnerable region of the atmosphere. It is important because many trace species, including ozone, have their greatest impact as greenhouse (infrared-absorbing) gases in this region. The addition of relatively small amounts of anthropogenic chemicals, such as nitrogen oxides, can have a dramatic effect on the abundance of ozone. Some of these pollutants are deposited directly, e.g., by aircraft, while others are transported in. The primary goal of this project was to measure several chemical compounds in the upper troposphere that will help us to understand how air is to transported to that part of the atmosphere; that is, does it come down from the stratosphere, does it rise from the surface via convection, and so on. To obtain adequate sampling to accomplish this goal, we proposed to make measurements from revenue aircraft during normal flight operations.

  13. Mixing ratios of trace gases in the austral polar atmosphere during August and September of 1987

    NASA Technical Reports Server (NTRS)

    Vedder, James F.; Heidt, Leroy E.; Pollock, Walter H.; Henry, Bruce E.; Lueb, Richard A.

    1988-01-01

    Mixing ratios are presented for a number of long-lived trace gases in the austral polar atmosphere during August and September of 1987. The recent discovery of a 12-year trend of increasing depletion of ozone over the Antarctic Continent in the spring of each year led to numerous theoretical interpretations and several scientific expeditions to the region. The results herein were obtained as part of a major effort involving penetration of the region of ozone depletion by NASA's multi-instrumented aircraft. One of the 14 instruments on the high-altitude ER-2 aircraft collected pressurized air samples between latitudes of 53 degrees and 72 degrees south at pressure altitudes up to 21 km in a series of 12 flights from Punta Arenas, Chile, over the Palmer Peninsula. The sampling system, located in the nose section of ER-2, has an inlet tube in the free airstream, a metal-bellows air pump, and 14 specially treated 1.6 l stainless-steel canisters for containing the pressurized air at 350 kPa. A typical flight profile consisted of a southbound path on the 428 K potential temperature surface, a descent to a pressure altitude of 13.7 km, a climb to the 460 K surface, and return on this surface. Mixing ratios for the trace gases were obtained from gas chromatographic analyses of the pressurized air samples. Of the species measured, the mixing ratios for CH4, CO, N2O, CF2 Cl2, CFCl3, CH3, CCl3, CCl4, and C2F3Cl3 are reported here.

  14. Characteristics of Fine Particles in an Urban Atmosphere—Relationships with Meteorological Parameters and Trace Gases

    PubMed Central

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

    Atmospheric fine particles (diameter < 1 μm) attract a growing global health concern and have increased in urban areas that have a strong link to nucleation, traffic emissions, and industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm–661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm–30 nm), Aitken mode (30 nm–100 nm), and accumulation mode (100 nm–661 nm) reached 4923 cm−3, 12193 cm−3 and 4801 cm−3, respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of “repeated, short-lived” nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of

  15. Characteristics of Fine Particles in an Urban Atmosphere-Relationships with Meteorological Parameters and Trace Gases.

    PubMed

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

    Atmospheric fine particles (diameter < 1 μm) attract a growing global health concern and have increased in urban areas that have a strong link to nucleation, traffic emissions, and industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm-661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm-30 nm), Aitken mode (30 nm-100 nm), and accumulation mode (100 nm-661 nm) reached 4923 cm(-3), 12193 cm(-3) and 4801 cm(-3), respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of "repeated, short-lived" nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of developing

  16. Disposal of acid gases with oilfield produced water

    SciTech Connect

    Duckworth, G.L.; Kopperson, D.; Horne, S.; Kohn, G.; Romansky, D.; Chan, C.

    1998-12-31

    With tightening environmental policies, many companies are investigating alternatives to atmospheric sulfur and greenhouse gas emissions. The oil and gas industry of Alberta, Canada typically recovers a high percentage of sulfur in large sour gas processing plants, but is often looking for a more cost effective approach to dealing with small volume plants. PanCanadian Petroleum Limited and DPH Engineering Inc. have developed a disposal scheme that makes low volume sour gas processing more affordable and easier to operate by disposing of acid gases in an aqueous phase to a disposal well. The development of this scheme utilized the results of reservoir studies, computer simulations, laboratory tests and field tests. This work has further resulted in the implementation of two full scale schemes to dissolve acid gas in produced water and inject it into deep subsurface formations. These schemes have operated with minimal problems and have met their environmental requirements.

  17. Increasing CO2 Coupled with Other Anthropogenic Perturbations: Effects on Ozone and Other Trace Gases

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Douglass, A. R.

    1999-01-01

    The GSFC 2D interactive chemistry-radiation-dynamics model has been used to study the effects on stratospheric trace gases of past and future CO2 increases coupled with changes in CFC'S, methane, and nitrous oxide. Previous simulations with the GSFC model showed that the stratospheric cooling calculated to result from doubling atmospheric CO2 would lead, in the absence of a growth of other anthropogenic gases, to a decrease in upper stratospheric NO(y) of roughly 15%. This work has been extended to simulate changes in stratospheric chemistry and dynamics occurring between the years 1960 and 2050. The simulations have been carried out with and without changes in CO2. In the low latitude upper stratosphere ozone is predicted to be 10% greater in 2050 than in 1990 when increased CO2 is included, compared with an increase of only 2% without the inclusion of CO2. In the low latitude lower stratosphere, ozone is predicted to decrease by about 1% between 1990 and 2050 when CO2 changes are taken into account, in contrast to an approximate 3% increase when they are not. The simulated behavior of water vapor is another example of the coupled responses. Between 1990 and 2050 low latitude water vapor is predicted to increase by 4% and 2% in the upper and lower stratosphere, respectively, without the inclusion of CO2 increases. with the inclusion of CO2 changes, the water vapor increases are predicted to be roughly 12% and 8%, for the upper and lower stratosphere, respectively.

  18. Atmospheric variability and emissions of halogenated trace gases near New York City

    NASA Astrophysics Data System (ADS)

    Santella, Nicholas; Ho, David T.; Schlosser, Peter; Gottlieb, Elaine; Munger, William J.; Elkins, James W.; Dutton, Geoffrey S.

    2012-02-01

    Elevated mixing ratios of chlorofluorocarbons (CFC-11 and CFC-12), and sulfur hexafluoride (SF 6) have been observed at Lamont-Doherty Earth Observatory (LDEO), located approximately 25 km north of New York City (NYC). Emissions and transport of these gases are of interest because of their global warming potential, the role of CFCs in depletion of stratospheric ozone and information they provide on the transport of atmospheric pollutants. Comparison of trace gas time series with meteorological data indicates that both NYC and the region to the southwest (New Jersey and the Philadelphia -Washington DC area) are significant sources of CFCs, and confirms that NYC is an unusually large source of SF 6. From 1996 to 2005 the elevation of CFC-12 mixing ratio above that of the remote (well mixed) atmosphere has decreased on average by 5.2 ± 0.6 ppt y -1, whereas that of CFC-11 has not changed significantly (0.0 ± 2.0 ppt y -1). From 1998 to 2006, the elevation of SF 6 mixing ratios above that of the remote atmosphere declined by 0.4 ± 0.1 ppt y -1. Time series of the same gases measured at Harvard Forest, 205 km northeast of LDEO, demonstrate transport of air masses with elevated levels of these gases from their source region to central Massachusetts. Emissions in the local area around LDEO were quantified through analysis of diurnal cycles. Local CFC-12 emissions decreased ca. 95% between 1996 and 2005 while CFC-11 emission decreased ca. 51% during the same period. Local SF 6 emissions decreased by 47% between 1998 and 2005.

  19. Airborne multi-axis DOAS measurements of atmospheric trace gases on CARIBIC long-distance flights

    NASA Astrophysics Data System (ADS)

    Dix, B.; Brenninkmeijer, C. A. M.; Frieß, U.; Wagner, T.; Platt, U.

    2009-11-01

    A DOAS (Differential Optical Absorption Spectroscopy) instrument was implemented and operated onboard a long-distance passenger aircraft within the framework of the CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). The instrument was designed to keep weight, size and power consumption low and to comply with civil aviation regulations. It records spectra of scattered light from three viewing directions (nadir, 10° above and below horizon) using a miniaturized telescope system. The telescopes are integrated in the main pylon of the inlet system which is mounted at the belly of the aircraft. Fibre bundles transmit light from the telescopes to spectrograph-detector units inside the DOAS container instrument. The latter is part of the removable CARIBIC instrument container, which is installed monthly on the aircraft for a series of measurement flights. During 30 flight operations within three years, measurements of HCHO, HONO, NO2, BrO, O3 and the oxygen dimer O4 were conducted. All of these trace gases except BrO could be analysed with a 30 s time resolution. HONO was detected for the first time in a deep convective cloud over central Asia, while BrO, NO2 and O3 could be observed in tropopause fold regions. Biomass burning signatures over South America could be seen and measurements during ascent and descent provided information on boundary layer trace gas profiles (e.g. NO2 or HCHO).

  20. Airborne multi-axis DOAS measurements of atmospheric trace gases on CARIBIC long-distance flights

    NASA Astrophysics Data System (ADS)

    Dix, B.; Brenninkmeijer, C. A. M.; Frieß, U.; Wagner, T.; Platt, U.

    2009-02-01

    A DOAS (Differential Optical Absorption Spectroscopy) instrument was implemented and operated onboard a long-distance passenger aircraft within the framework of the CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). The instrument was designed to keep weight, size and power consumption low and to comply with civil aviation regulations. It records spectra of scattered light from three viewing directions (nadir, 10° above and below horizon) using a miniaturized telescope system. The telescopes are integrated in the main pylon of the inlet system which is mounted at the belly of the aircraft. Fibre bundles transmit light from the telescopes to spectrograph-detector units inside the DOAS container instrument. The latter is part of the removable CARIBIC instrument container, which is installed monthly on the aircraft for a series of measurement flights. During 30 flight operations within three years, measurements of HCHO, HONO, NO2, BrO, O3 and the oxygen dimer O4 were conducted. All of these trace gases except BrO could be analysed with a 30 s time resolution. HONO was detected for the first time in a deep convective cloud over central Asia. BrO, NO2 and O3 could be observed in tropopause fold regions, biomass burning signatures over South America could be seen and measurements during ascent and descent provided information on boundary layer trace gas profiles (e.g. NO2 or HCHO).

  1. Validation of Global Climatologies of Trace Gases Using NASA Global Tropospheric Experiment (GTE) Data

    NASA Technical Reports Server (NTRS)

    Courchaine, Brian; Venable, Jessica C.

    1995-01-01

    Methane is an important trace gas because it is a greenhouse gas that affects the oxidative capacity of the atmosphere. It is produced from biological and anthropogenic sources, and is increasing globally at a rate of approximately 0.6% per year [Climate Change 1992, IPCC]. By using National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) ground station data, a global climatology of methane values was produced. Unfortunately, because the NOAA/CMDL ground stations are so sparse, the global climatology is low resolution. In order to compensate for this low resolution data, it was compared to in-situ flight data obtained from the NASA Global Tropospheric Experiment (GTE). The smoothed ground station data correlated well with the flight data. Thus, for the first time it is shown that the smoothing process used to make global contours of methane using the ground stations is a plausible way to approximate global atmospheric concentrations of the gas. These verified climatologies can be used for testing large-scale models of chemical production, destruction, and transport. This project develops the groundwork for further research in building global climatologies from sparse ground station data and studying the transport and distribution of trace gases.

  2. Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Melroy, H.; Wilson, E. L.; Georgieva, E.

    2012-12-01

    We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent pathlength reduces the mass from ~150 kg to ~0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately 1 meter in diameter by 0.05 m in height (mass and volume reductions of >99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to ~30 ppb for formaldehyde, and ~500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these

  3. Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Melroy, Hilary R.; Wilson, Emily L.; Georgieva, Elena

    2012-01-01

    We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent path length reduces the mass from approximately 150 kg to approximately 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately 1 meter in diameter by 0.05 m in height (mass and volume reductions of greater than 99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to approximately 30 ppb for formaldehyde, and approximately 500 ppb for methane. We expect custom

  4. Exomars orbiter science and data-relay mission / looking for trace gases on Mars

    NASA Astrophysics Data System (ADS)

    Fratacci, Olivier

    EXOMARS Orbiter Module: looking for trace gas on Mars and providing data relay support for future Mars Surface assets O.Fratacci, M.Mesrine, H.Renault, Thales Alenia Space France B.Musetti, M.Montagna, Thales Alenia Space Italy M.Kesselmann, M.Barczewski OHB P.Mitschdoerfer, D.Dellantonio Euro-pean Space Agency / ESTEC The European Space Agency (ESA) in a joint cooperation with NASA, will launch in 2016 the EXOMARS spacecraft composite to develop European landing technologies and provide a science orbiter with data-relay capability around Mars until end 2022. The spacecraft composite is composed of the Orbitr Module (OM), provided by TAS-France, an entry descent and landing demonstrator module (EDM) provided by TAS-Italy, and a set of six scientific payloads to be selected by the JPL during 2010. Recent observations of the planet Mars have indicated detection of methane as well as temporal, perhaps spatial variability in the detected signal while current photochemical models cannot explain the presence of methane in the atmosphere of Mars nor its reported rapid variations in space and time. The triple scientific objectives that drive the selection of these six instruments for the Exomars 2016 mission is to detect trace gases in Mars atmosphere, to characterise their spatial and temporal variation and to explore the source of the key trace gases (e.g. methane) on the surface. The launch is scheduled in January 2016 from Kennedy Space Center (KSC) using an ATLAS V 421 launcher with a total launch mass of 4.4 tons. After release of the EDM on Mars, the OM will perform the Mars Orbit Insertion manoeuvre and then reduce its elliptic orbit by implementing the first European Aerobraking around Mars for about 6 to 9 months, to finally end on a circular 400x400km orbit with an altitude in the range of 350km to 420km. From this orbit, a science phase will follow lasting 2 years in which the Mars atmosphere and surface is continuously observed. Science instruments composed of

  5. Carbon dioxide Information Analysis Center and World Data Center: A for Atmospheric trace gases. Annual progress report, FY 1994

    SciTech Connect

    Burtis, M.D.; Cushman, R.M.; Boden, T.A.; Jones, S.B.; Nelson, T.R.; Stoss, F.W.

    1995-03-01

    This report summarizes the activities and accomplishments made by the Carbon Dioxide Information Analysis Center and World Data Center-A for Atmospheric Trace Gases during the fiscal year 1994. Topics discussed in this report include; organization and staff, user services, systems, communications, Collaborative efforts with China, networking, ocean data and activities of the World Data Center-A.

  6. Indoor exposures to fine aerosols and acid gases.

    PubMed

    Koutrakis, P; Brauer, M; Briggs, S L; Leaderer, B P

    1991-11-01

    Indoor exposures to aerosols and gases are associated with both indoor and outdoor air pollution sources. The identification of sources and the assessment of their relative contribution can be a complicated process due to a) the presence of numerous indoor sources, which can vary from building to building; b) the uncertainties associated with the estimation of the impact of outdoor sources on indoor air quality; c) the interactions between pollutants; and d) the importance of reactions between pollutants and indoor surfaces. It is well established that fine particles (diameter less than or equal to 2.5 microns) originating from outdoor sources such as automobiles, oil and coal combustion, incineration, and diverse industrial activities can penetrate into the indoor environment. Indoor/outdoor ratios, usually varying between 0.4 and 0.8, depend on parameters such as particle size and density, air exchange rate, and the surface-to-volume ratio of the indoor environment. Determining fine particle elemental composition makes it possible to identify the contribution of different outdoor sources. This paper focuses on the origin and the concentration of indoor aerosols and acid gases by highlighting the results from two indoor air quality studies. PMID:1821374

  7. Development of 2-D-MAX-DOAS and retrievals of trace gases and aerosols optical properties

    NASA Astrophysics Data System (ADS)

    Ortega, Ivan

    Air pollution is a major problem worldwide that adversely a_ects human health, impacts ecosystems and climate. In the atmosphere, there are hundreds of important compounds participating in complex atmospheric reactions linked to air quality and climate. Aerosols are relevant because they modify the radiation balance, a_ect clouds, and thus Earth albedo. The amount of aerosol is often characterized by the vertical integral through the entire height of the atmosphere of the logarithm fraction of incident light that is extinguished called Aerosol Optical Depth (AOD). The AOD at 550 nm (AOD550) over land is 0.19 (multi annual global mean), and that over oceans is 0.13. About 43 % of the Earth surface shows AOD550 smaller than 0.1. There is a need for measurement techniques that are optimized to measure aerosol optical properties under low AOD conditions, sample spatial scales that resemble satellite ground-pixels and atmospheric models, and help integrate remote sensing and in-situ observations to obtain optical closure on the effects of aerosols and trace gases in our changing environment. In this work, I present the recent development of the University of Colorado two dimensional (2-D) Multi-AXis Differential Optical Absorption Spectroscopy (2-D-MAX-DOAS) instrument to measure the azimuth and altitude distribution of trace gases and aerosol optical properties simultaneously with a single instrument. The instrument measures solar scattered light from any direction in the sky, including direct sun light in the hyperspectral domain. In Chapter 2, I describe the capabilities of 2-D measurements in the context of retrievals of azimuth distributions of nitrogen dioxide (NO2), formaldehyde (HCHO), and glyoxal (CHOCHO), which are precursors for tropospheric O3 and aerosols. The measurements were carried out during the Multi-Axis DOAS Comparison campaign for Aerosols and Trace gases (MAD-CAT) campaign in Mainz, Germany and show the ability to bridge spatial scales to

  8. Theoretical computation of trace gases retrieval random error from measurements of high spectral resolution infrared sounder

    NASA Technical Reports Server (NTRS)

    Huang, Hung-Lung; Smith, William L.; Woolf, Harold M.; Theriault, J. M.

    1991-01-01

    The purpose of this paper is to demonstrate the trace gas profiling capabilities of future passive high spectral resolution (1 cm(exp -1) or better) infrared (600 to 2700 cm(exp -1)) satellite tropospheric sounders. These sounders, such as the grating spectrometer, Atmospheric InfRared Sounders (AIRS) (Chahine et al., 1990) and the interferometer, GOES High Resolution Interferometer Sounder (GHIS), (Smith et al., 1991) can provide these unique infrared spectra which enable us to conduct this analysis. In this calculation only the total random retrieval error component is presented. The systematic error components contributed by the forward and inverse model error are not considered (subject of further studies). The total random errors, which are composed of null space error (vertical resolution component error) and measurement error (instrument noise component error), are computed by assuming one wavenumber spectral resolution with wavenumber span from 1100 cm(exp -1) to 2300 cm(exp -1) (the band 600 cm(exp -1) to 1100 cm(exp -1) is not used since there is no major absorption of our three gases here) and measurement noise of 0.25 degree at reference temperature of 260 degree K. Temperature, water vapor, ozone and mixing ratio profiles of nitrous oxide, carbon monoxide and methane are taken from 1976 US Standard Atmosphere conditions (a FASCODE model). Covariance matrices of the gases are 'subjectively' generated by assuming 50 percent standard deviation of gaussian perturbation with respect to their US Standard model profiles. Minimum information and maximum likelihood retrieval solutions are used.

  9. Organic trace gases of oceanic origin observed at South Pole during ISCAT 2000

    NASA Astrophysics Data System (ADS)

    Swanson, Aaron L.; Davis, Douglas D.; Arimoto, Richard; Roberts, Pauline; Atlas, Elliot L.; Flocke, Frank; Meinardi, Simone; Sherwood Rowland, F.; Blake, Donald R.

    2004-10-01

    Volatile organic compounds (VOCs) were measured at the South Pole (SP) from late Austral spring to mid-summer 2000 as part of the Investigation of Sulfur Chemistry in the Antarctic Troposphere Program (ISCAT-2000). This paper focuses on VOCs that are directly emitted from the ocean, specifically dimethyl sulfide (DMS), methyl nitrate (CH3ONO2), methyl iodide (CH3I) and bromoform (CHBr3). A partial seasonal cycle of these gases was also recorded during the year following ISCAT-2000. During the summer, the SP periodically receives relatively fresh marine air containing short-lived oceanic trace gases, such as DMS (τ≈1 day). However, DMS was not detected at the SP until January even though DMS emissions from the Southern Ocean typically start peaking in November and elevated levels of other ocean-derived VOCs, including CH3ONO2 and CHBr3, were observed in mid-November. We speculate that in November and December most of the DMS is oxidized before it reaches the SP: a strong correlation between CH3ONO2 and methane sulfonate (MSA), an oxidation product of DMS, supports this hypothesis. Based on a limited number of samples taken over the course of one year, CH3ONO2 apparently accumulates to a quasi-steady-state level over the SP in winter, most likely due to continuing emissions of the compound coupled with a lower rate of photochemical destruction. Oceanic emissions were concluded to be the dominant source of alkyl nitrates at the SP; this is in sharp contrast to northern high latitudes where total alkyl nitrate mixing ratios are dominated by urban sources.

  10. Soil microorganisms as controllers of atmospheric trace gases (H2, CO, CH4, OCS, N2O, and NO).

    PubMed Central

    Conrad, R

    1996-01-01

    Production and consumption processes in soils contribute to the global cycles of many trace gases (CH4, CO, OCS, H2, N2O, and NO) that are relevant for atmospheric chemistry and climate. Soil microbial processes contribute substantially to the budgets of atmospheric trace gases. The flux of trace gases between soil and atmosphere is usually the result of simultaneously operating production and consumption processes in soil: The relevant processes are not yet proven with absolute certainty, but the following are likely for trace gas consumption: H2 oxidation by abiontic soil enzymes; CO cooxidation by the ammonium monooxygenase of nitrifying bacteria; CH4 oxidation by unknown methanotrophic bacteria that utilize CH4 for growth; OCS hydrolysis by bacteria containing carbonic anhydrase; N2O reduction to N2 by denitrifying bacteria; NO consumption by either reduction to N2O in denitrifiers or oxidation to nitrate in heterotrophic bacteria. Wetland soils, in contrast to upland soils are generally anoxic and thus support the production of trace gases (H2, CO, CH4, N2O, and NO) by anaerobic bacteria such as fermenters, methanogens, acetogens, sulfate reducers, and denitrifiers. Methane is the dominant gaseous product of anaerobic degradation of organic matter and is released into the atmosphere, whereas the other trace gases are only intermediates, which are mostly cycled within the anoxic habitat. A significant percentage of the produced methane is oxidized by methanotrophic bacteria at anoxic-oxic interfaces such as the soil surface and the root surface of aquatic plants that serve as conduits for O2 transport into and CH4 transport out of the wetland soils. The dominant production processes in upland soils are different from those in wetland soils and include H2 production by biological N2 fixation, CO production by chemical decomposition of soil organic matter, and NO and N2O production by nitrification and denitrification. The processes responsible for CH4 production

  11. Soil microorganisms as controllers of atmospheric trace gases (H2, CO, CH4, OCS, N2O, and NO).

    PubMed

    Conrad, R

    1996-12-01

    Production and consumption processes in soils contribute to the global cycles of many trace gases (CH4, CO, OCS, H2, N2O, and NO) that are relevant for atmospheric chemistry and climate. Soil microbial processes contribute substantially to the budgets of atmospheric trace gases. The flux of trace gases between soil and atmosphere is usually the result of simultaneously operating production and consumption processes in soil: The relevant processes are not yet proven with absolute certainty, but the following are likely for trace gas consumption: H2 oxidation by abiontic soil enzymes; CO cooxidation by the ammonium monooxygenase of nitrifying bacteria; CH4 oxidation by unknown methanotrophic bacteria that utilize CH4 for growth; OCS hydrolysis by bacteria containing carbonic anhydrase; N2O reduction to N2 by denitrifying bacteria; NO consumption by either reduction to N2O in denitrifiers or oxidation to nitrate in heterotrophic bacteria. Wetland soils, in contrast to upland soils are generally anoxic and thus support the production of trace gases (H2, CO, CH4, N2O, and NO) by anaerobic bacteria such as fermenters, methanogens, acetogens, sulfate reducers, and denitrifiers. Methane is the dominant gaseous product of anaerobic degradation of organic matter and is released into the atmosphere, whereas the other trace gases are only intermediates, which are mostly cycled within the anoxic habitat. A significant percentage of the produced methane is oxidized by methanotrophic bacteria at anoxic-oxic interfaces such as the soil surface and the root surface of aquatic plants that serve as conduits for O2 transport into and CH4 transport out of the wetland soils. The dominant production processes in upland soils are different from those in wetland soils and include H2 production by biological N2 fixation, CO production by chemical decomposition of soil organic matter, and NO and N2O production by nitrification and denitrification. The processes responsible for CH4 production

  12. Sensitivity of net thermal flux to the abundance of trace gases in the lower atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Lee, Yeon Joo; Sagawa, Hideo; Haus, Rainer; Stefani, Stefania; Imamura, Takeshi; Titov, Dmitrij V.; Piccioni, Giuseppe

    2016-09-01

    We calculated the net thermal flux in the atmosphere of Venus from the surface to 100 km altitude. Our atmospheric model was carefully constructed especially for altitudes below the clouds (<48 km), using recent CO2 absorption data. It includes updated collision-induced absorptions in the <250 cm-1, 1200-1500 cm-1, and 2650-3130 cm-1 wave number ranges. We studied sensitivity of the net thermal flux below the clouds on the abundances of trace gases that were varied within the range reported by observations. Our results reveal a considerable effect of trace gases on radiative budget. We successfully simulate net thermal flux profiles measured in situ by the Night and North probes of Pioneer Venus using 20-50 ppmv H2O, suggesting that the high H2O abundance of 200 ppmv derived in the earlier analysis is not required. Our sensitivity study shows that the trace gases SO2, H2O, and OCS are effective thermal agents, while CO and HCl influences are rather weak. We suggest that the influence of the former three gases should be taken into account to estimate the net radiative energy in the deep atmosphere.

  13. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  14. Study on the kinetic characteristics of trace harmful gases for a two-person-30-day integrated CELSS test.

    PubMed

    Guo, Shuangsheng; Ai, Weidang; Fei, Jinxue; Xu, Guoxin; Zeng, Gu; Shen, Yunze

    2015-05-01

    A two-person-30-day controlled ecological life support system (CELSS) integrated test was carried out, and more than 30 kinds of trace harmful gases including formaldehyde, benzene, and ammonia were measured and analyzed dynamically. The results showed that the kinds and quantities of the trace harmful gases presented a continuously fluctuating state during the experimental period, but none of them exceed the spacecraft maximum allowable concentration (SMAC). The results of the Pre-Test (with two persons without plants for 3 days) and the Test (with two persons and four kinds of plants for 30 days) showed that there are some notable differences for the compositions of the trace harmful gases; the volatile organic compounds (VOCs) such as toluene, hexane, and acetamide were searched out in the Pre-Test, but were not found in the Test. Moreover, the concentrations of the trace harmful gases such as acetic benzene, formaldehyde, and ammonia decreased greatly in the Test more than those in the Pre-Test, which means that the plants can purify these gases efficiently. In addition, the VOCs such as carbon monoxide, cyclopentane, and dichloroethylene were checked out in the Test but none in the Pre-Test, which indicates that these materials might be from the crew's metabolites or those devices in the platform. Additionally, the ethylene released specially by plants accumulated in the later period and its concentration reached nearly ten times of 0.05 mg m(-3) (maximum allowed concentration for plant growth, which must have promoted the later withering of plants). We hoped that the work can play a referring function for controlling VOCs effectively so that future more CELSS integrating tests can be implemented smoothly with more crew, longer period, and higher closure. PMID:25483969

  15. Study on the kinetic characteristics of trace harmful gases for a two-person-30-day integrated CELSS test.

    PubMed

    Guo, Shuangsheng; Ai, Weidang; Fei, Jinxue; Xu, Guoxin; Zeng, Gu; Shen, Yunze

    2015-05-01

    A two-person-30-day controlled ecological life support system (CELSS) integrated test was carried out, and more than 30 kinds of trace harmful gases including formaldehyde, benzene, and ammonia were measured and analyzed dynamically. The results showed that the kinds and quantities of the trace harmful gases presented a continuously fluctuating state during the experimental period, but none of them exceed the spacecraft maximum allowable concentration (SMAC). The results of the Pre-Test (with two persons without plants for 3 days) and the Test (with two persons and four kinds of plants for 30 days) showed that there are some notable differences for the compositions of the trace harmful gases; the volatile organic compounds (VOCs) such as toluene, hexane, and acetamide were searched out in the Pre-Test, but were not found in the Test. Moreover, the concentrations of the trace harmful gases such as acetic benzene, formaldehyde, and ammonia decreased greatly in the Test more than those in the Pre-Test, which means that the plants can purify these gases efficiently. In addition, the VOCs such as carbon monoxide, cyclopentane, and dichloroethylene were checked out in the Test but none in the Pre-Test, which indicates that these materials might be from the crew's metabolites or those devices in the platform. Additionally, the ethylene released specially by plants accumulated in the later period and its concentration reached nearly ten times of 0.05 mg m(-3) (maximum allowed concentration for plant growth, which must have promoted the later withering of plants). We hoped that the work can play a referring function for controlling VOCs effectively so that future more CELSS integrating tests can be implemented smoothly with more crew, longer period, and higher closure.

  16. A sensitivity study for far infrared balloon-borne limb emission sounding of stratospheric trace gases

    NASA Astrophysics Data System (ADS)

    Xu, J.; Schreier, F.; Vogt, P.; Doicu, A.; Trautmann, T.

    2013-05-01

    This paper presents a sensitivity study performed for trace gases retrieval from synthetic observations by TELIS (TErahertz and submillimeter LImb Sounder) which is a stratospheric balloon-borne cryogenic heterodyne spectrometer. Issues pertaining to hydroxyl radical (OH) retrieval from the far infrared measurements by the 1.8 THz channel are addressed. The study is conducted by a retrieval code PILS (Profile Inversion for Limb Sounding) developed to solve the nonlinear inverse problems arising in the analysis of infrared/microwave limb sounding measurements. PILS combines a line-by-line forward model with automatic differentiation for computing Jacobians and employs regularized nonlinear least squares inversion. We examine the application of direct and iterative regularization methods and evaluate the performance of single- and multi-profile retrievals. Sensitivities to expected errors in calibration procedure, instrumental knowledge and atmospheric profiles have been analyzed. Nonlinearity effect, inaccurate sideband ratio, and pointing error turned out to be the dominant error sources. Furthermore, the capability of multi-channel simultaneous retrieval from the far infrared and submillimeter data has been investigated. The errors and averaging kernels infer that the quality of the obtained hydrogen chloride (HCl) can be improved by significantly better exploitation of information from the observations.

  17. Emission rates of sulfur dioxide, trace gases and metals from Mount Erebus, Antartica

    SciTech Connect

    Kyle, P.R.; Meeker, K. ); Finnegan, D. )

    1990-11-01

    SO{sub 2} emission rates have been measured annually since 1983 at Mount Erebus, Antarctica by correlation spectrometer (COSPEC V). Following a 4 month period of sustained strombolian activity in late 1984, SO{sub 2} emissions declined from 230 Mg/day in 1983 to 25 Mg/day and then slowly increased from 16 Mg/day in 1985 to 51 Mg/day in 1987. Nine sets of filter packs containing partcle and {sup 7}LiOH treated filters were collected in the plume in 1986 and analyzed by neutron activation. Using the COSPEC data and measured element/S ratios on the filters, emission rates have been determined for trace gases and metals. The authors infer HCl and HF emissions in 1983 to be about 1200 and 500 Mg/day, respectively. Mt Erebus has therefore been an important source of halogens to the Anarctic atmosphere and could be responsible for excess Cl found in Central Antarctica snow.

  18. Recent developments in high altitude aircraft sampling - Mount St. Helens and stratospheric trace gases

    NASA Astrophysics Data System (ADS)

    Leifer, R.; Sommers, K. G.; Guggenheim, S. F.; Fisenne, I.

    1981-02-01

    An ultra-clean, low volume gas sampling system (CLASS), flown aboard a high altitude aircraft (WB-57F), and providing information on stratospheric trace gases is presented. Attention is given to the instrument design and the electronic control design. Since remote operation is mandatory on the WB-57F, a servo pressure transducer, electrical pressure switch for automatic shutdown, and a mechanical safety relief valve were installed on the sampling manifold, indicated on the CLASS flow chart. The electronic control system consists of hermetically sealed solid state timers, relays, and a stepping switch, for controlling the compressor pump and solenoid valves. In designing the automatic control system, vibration, shock, acceleration, extreme low temperature, and aircraft safety were important considerations. CLASS was tested on three separate occasions, and tables of analytical data from these flights are presented. Readiness capability was demonstrated when the Mount St. Helens eruption plume of May 18, 1980, was intercepted, and it was concluded that no large injection of Rn-222 entered the stratosphere or troposphere from the eruption.

  19. Lidar remote sensing of tropospheric pollutants and trace gases - Programs of NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Browell, E. V.

    1978-01-01

    NASA Langley Research Center is engaged in a number of in-house and contracted programs to develop, evaluate, and apply lidar techniques to remote measurements of pollutant gases, trace molecules, and aerosols. The differential absorption lidar (DIAL) research programs include the development and evaluation of a UV DIAL system for remote measurements of SO2 and O3 concentrations and aerosol dispersion in urban and power-plant stack plumes, a near-IR DIAL system for vertical measurements of water vapor concentrations, and a high-power tunable IR DIAL system which will measure the concentration of gas species that have absorption features in the 1.4- to 4.4-micron wavelength range. The lidar programs which deal with aerosol measurements include the evaluation of a mobile ruby lidar system for use in plume dispersion model verification and the development of a high-spectral-resolution lidar system for measurement of aerosol extinction and backscattering coefficients. System characteristics and measurement sensitivities are discussed, and comparisons are made between simulations and experimental results.

  20. Emission of methane and other trace gases from the Amazon Varzea

    NASA Technical Reports Server (NTRS)

    Richey, Jeffrey E.; Devol, Allan H.

    1986-01-01

    Researchers measured the distributions and fluxes of methane and other trace gases from the various Amazon floodplain environments. These were determined during both a large scale, quasi-synoptic survey along a 2000 km reach of the Amazon river and an intensive local study (by J. Melack, R. Harriss et al.) covering a six-week period. The environments studied included the major rivers, connecting channels (paranas), floating macrophyte beds, flooded forests, open lakes and recently wetted soils. The results are summarized. Measured rates of methane emission averaged about 300 mg m-2 d-1, but with considerable variance, and were comparable to or higher than previously reported emissions from similar temperature zone environments. In general, areas covered by floating macrophytes showed the highest emissions. Individual hotspots had among the highest rates ever observed, over 10 g m-2 d-1. The high methane emissions appear to result because about 50% of the organic matter fixed on the floodplain (either terrestrial or aquatic) that is oxidized in the water is decomposed anaerobically via methanogensis. Measured fluxes of methane to the atmosphere appear to be significantly correlated with surface water dissolved methane concentrations.

  1. Long Range Transport of Aerosols and Trace Gases from China: The Role of Dry Convection.

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Levy, R.; Li, C.; Li, Z.; Lackson, M. T.; Jeffrey, S.

    2006-05-01

    Substantial concentrations of trace gases and aerosols are lofted and carried from Asia over the Pacific producing an inter-hemispheric impact on atmospheric chemistry and climate. The meteorological mechanism leading to this large-scale transport of dust and pollutants remains a major uncertainty in quantifying the global effects of emissions from the developing world. Models and downwind measurements have identified isentropic advection associated with wave cyclones (warm conveyor belt, WCB,circulation) as an important mechanism. We present data from a case study conducted s part of EAST-AIRE in April 2005 in which upstream convection, rather that WCB lofting appears to dominate. Observations from instrumented aircraft flights (O3, CO, SO2, and aerosol optical properties), back trajectories, and satellite images of clouds (GOES) and aerosols (MODIS) are analyzed. These show that dry (non-precipitating) convection ahead of cold fronts can be an important mechanism for converting local air pollution problems into regional or global atmospheric chemistry problems. Climatological spring (MAM) precipitation over NE China is low, about 90 mm compared to 290 mm over the NE US. Cloud cover, however, is similar with cumulus clouds reported about 7% of the time over NE China and about 9% of the time over the NE US suggesting that this is not an isolated event. Evaluation of models' convective schemes and further observations near the source regions are called for.

  2. ACID GASES IN CO2-RICH SUBSURFACE GEOLOGIC ENVIRONMENTS

    SciTech Connect

    Chialvo, Ariel A; Vlcek, Lukas; Cole, David

    2013-01-01

    The analysis of species behavior involving dilute fluid environments has been crucial for the advance of modern solvation thermodynamics through molecular-based formalisms to guide the development of macroscopic regression tools in the description of fluid behavior and correlation of experimental data (Chialvo 2013). Dilute fluid environments involving geologic formations are of great theoretical and practical relevance regardless of the thermodynamic state conditions. The most challenging systems are those involving highly compressible and reactive confined environments, i.e., where small perturbations of pressure and/or temperature can trigger considerable density changes. This in turn can alter significantly the species solvation, their preferential solvation, and consequently, their reactivity with one another and with the surrounding mineral surfaces whose outcome is the modification of the substrate porosity and permeability, and ultimately, the integrity of the mineral substrates. Considering that changes in porosity and permeability resulting from dissolution and precipitation phenomena in confined environments are at the core of the aqueous CO2-mineral interactions, and that caprock integrity (e.g., sealing capacity) depends on these key parameters, it is imperative to gain fundamental understanding of the mineral-fluid interfacial phenomena and fluid-fluid equilibria under mineral confinement at subsurface conditions. In order to undertand the potential effects of acid gases as contaminants of supercritical CO2 streams, in the next section we will discuss the thermodynamic behavior of CO2 fluid systems by addressing two crucial issues in the context of carbon capture, utilization and sequestration (CCUS) technologies: (i) Why should we consider (acid gas) CO2 impurities? and (ii) Why are CO2 fluid - mineral interactions of paramount relevance?

  3. Carbon Dioxide Information Analysis Center and World Data Center for Atmospheric Trace Gases, Fiscal Year 2002 Annual Report

    SciTech Connect

    Cushman, R.M.

    2003-08-28

    The Carbon Dioxide Information Analysis Center (CDIAC), which includes the World Data Center (WDC) for Atmospheric Trace Gases, is the primary global change data and information analysis center of the U.S. Department of Energy (DOE). More than just an archive of data sets and publications, CDIAC has, since its inception in 1982, enhanced the value of its holdings through intensive quality assurance, documentation, and integration. Whereas many traditional data centers are discipline-based (for example, meteorology or oceanography), CDIAC's scope includes potentially anything and everything that would be of value to users concerned with the greenhouse effect and global climate change, including atmospheric concentrations and atmospheric emissions of carbon dioxide (CO{sub 2}) and other radiatively active gases; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; long-term climate trends; the effects of elevated CO{sub 2} on vegetation; and the vulnerability of coastal areas to rising sea levels.

  4. Trace gases generated in closed plant cultivation systems and their effects on plant growth.

    PubMed

    Tani, A; Kiyota, M; Aiga, I

    1995-12-01

    Interactions between plants and trace gases, especially ethylene, were investigated from two different viewpoints; ethylene is toxic for plant growth, whereas the ethylene release rate of plants can be utilized as a plant growth indicator. When lettuce plants and shiitake mushroom mycelium were cultivated in closed chambers, ethylene concentration increased with time. Ethylene was released both from lettuce plant and from shiitake mushroom mycelium. Dioctyl phthalate (DOP) and Dibutyl phthalate (DBP) were detected, and these concentrations reached 3.7 ngL-1 for DOP and 2.4 ngL-1 for DBP 4 days after closing. Organic solvents such as xylene and toluene and organic siloxane were detected with GCMS. Visible injury was observed in lettuce plants cultivated in the chambers and it seemed to result from trace contaminants such as DOP, DBP, organic solvents, dimethylsiloxane polymer, and ethylene. In order to obtain basic data of ethylene evolution from plants, ethylene concentration in a closed chamber in which the plants were cultivated under a controlled environment (25 degrees C air temperature, 60-70% relative humidity, 250-300 micromoles m-2 s-1 photosynthetic photon flux density (PPFD)) was measured. Lettuce (Lactuca sativa L. cv. Okayama) released ethylene more than Brassica rapa var. pervidis, Brassica campestris var. communis, and Brassica campestris var. narinosa. Ethylene release rate of intact lettuce plant was highly correlated with plant growth parameters such as dry weight, leaf area and photosynthetic rate. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period. Increase in ambient ethylene level influenced lettuce growth even at the concentration of 0.1 microliter L-1. The level of ethylene inhibited leaf expansion and slightly accelerated chlorophyll degradation. It did not affect photosynthesis and transpiration, and also little affected dry matter

  5. Trace gases generated in closed plant cultivation systems and their effects on plant growth.

    PubMed

    Tani, A; Kiyota, M; Aiga, I

    1995-12-01

    Interactions between plants and trace gases, especially ethylene, were investigated from two different viewpoints; ethylene is toxic for plant growth, whereas the ethylene release rate of plants can be utilized as a plant growth indicator. When lettuce plants and shiitake mushroom mycelium were cultivated in closed chambers, ethylene concentration increased with time. Ethylene was released both from lettuce plant and from shiitake mushroom mycelium. Dioctyl phthalate (DOP) and Dibutyl phthalate (DBP) were detected, and these concentrations reached 3.7 ngL-1 for DOP and 2.4 ngL-1 for DBP 4 days after closing. Organic solvents such as xylene and toluene and organic siloxane were detected with GCMS. Visible injury was observed in lettuce plants cultivated in the chambers and it seemed to result from trace contaminants such as DOP, DBP, organic solvents, dimethylsiloxane polymer, and ethylene. In order to obtain basic data of ethylene evolution from plants, ethylene concentration in a closed chamber in which the plants were cultivated under a controlled environment (25 degrees C air temperature, 60-70% relative humidity, 250-300 micromoles m-2 s-1 photosynthetic photon flux density (PPFD)) was measured. Lettuce (Lactuca sativa L. cv. Okayama) released ethylene more than Brassica rapa var. pervidis, Brassica campestris var. communis, and Brassica campestris var. narinosa. Ethylene release rate of intact lettuce plant was highly correlated with plant growth parameters such as dry weight, leaf area and photosynthetic rate. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period. Increase in ambient ethylene level influenced lettuce growth even at the concentration of 0.1 microliter L-1. The level of ethylene inhibited leaf expansion and slightly accelerated chlorophyll degradation. It did not affect photosynthesis and transpiration, and also little affected dry matter

  6. Measurement of gas/water uptake coefficients for trace gases active in the marine environment

    SciTech Connect

    Davidovits, P. . Dept. of Chemistry); Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E. . Center for Chemical and Environmental Physics)

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean's surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry's law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  7. Transport of trace gases into the Tropical Tropopause Layer: the CAST experiment

    NASA Astrophysics Data System (ADS)

    Harris, N. R.

    2013-12-01

    The transport of trace gases from the lower troposphere into and through the Tropical Tropopause Layer is of fundamental importance in determining the chemical composition of the stratosphere. This occurs in convection which is particularly strong in the West Pacific in Boreal winter. A joint aircraft experiment will take place which involves the NERC CAST (Coordinated Airborne Studies in the Tropics), the NASA ATTREX (Airborne Tropical TRopopause EXperiment) and the NSF/NCAR CONTRAST Convective Transport of Active Species in the Tropics) projects. These will be supplemented by ground-based and sonde measurements made at Palau in CAST and in Biak in the Japanese SOWER experiment. One aim of the combined experiment is to measure the chemical composition of both the inflow and the outflow of the convection. The use of tracers with different lifetimes, including a range of short-lived halocarbons and hydrocarbons, should reveal a great deal about the mass fluxes of air from the lower troposphere to different altitudes in the TTL. This presentation describes the studies examining the composition and structure of the TTL, the plans for the aircraft and ground-based measurements, and the analyses to be used for interpretation. Examples of similar analyses based on the ATTREX measurements made in the East Pacific in February 2013 will be presented. These show the variability in the amount of air transported from the lower troposphere into the TTL calculated by the UK Met Office's NAME dispersion model as well as that model's ability to reproduce tracer distributions in the TTL.

  8. Emissions of methane, nitrous oxide, and other trace gases from rice fields in China

    NASA Astrophysics Data System (ADS)

    Khalil, M. A. K.; Rasmussen, R. A.; Shearer, M. J.; Chen, Zong-Liang; Yao, Heng; Yang, Jun

    1998-10-01

    We measured the emissions of methane, nitrous oxide, and other environmentally important trace gases from rice fields in China. The experiments were conducted near Beijing, representing temperate latitude rice agriculture, and at Guangzhou, representing tropical and subtropical agriculture. These studies complement our intensive research at Tu Zu in China (subtropical) and the work near Bogor, Indonesia, representing tropical rice agriculture. The experiments described here span 5 years between 1992 and 1996. The seasonally averaged methane emissions from Beijing were about 9 (5-16) mg m-2 h-1. Emissions from the first crop of the year at Guangzhou were about 5 (2-8) mg m-2 h-1 and about 30 (18-54) mg m-2 h-1 from the second crop. Measurements of nitrous oxide fluxes from the same rice fields show that emissions are confined to events that consist of high fluxes decaying to zero within a few days. Some of the events appear to be triggered by fertilizer applications. It is apparent that rice fields using nitrogen-based fertilizers are a source of N2O, but a robust estimate of whole season average emission rate is still not possible. The composite of all the N2O fluxes we observed gives a geometric mean of about 70 μg m-2 h-1. These rates are high enough to suggest that the rice fields could be a globally important source of N2O. As the agricultural practices change from use of organic fertilizers to nitrogen-based fertilizers, the role of N2O emissions from rice fields may become more important in its global budget. We also observed that chloroform and carbon monoxide were emitted from all fields studied. The flux of CO is not large enough to be important on the global scale, but the emissions of chloroform may be.

  9. Interannual variability of tropospheric trace gases and aerosols: The role of biomass burning emissions

    NASA Astrophysics Data System (ADS)

    Voulgarakis, Apostolos; Marlier, Miriam E.; Faluvegi, Greg; Shindell, Drew T.; Tsigaridis, Kostas; Mangeon, Stéphane

    2015-07-01

    Fires are responsible for a range of gaseous and aerosol emissions. However, their influence on the interannual variability of atmospheric trace gases and aerosols has not been systematically investigated from a global perspective. We examine biomass burning emissions as a driver of interannual variability of large-scale abundances of short-lived constituents such as carbon monoxide (CO), hydroxyl radicals (OH), ozone, and aerosols using the Goddard Institute for Space Studies ModelE composition-climate model and a range of observations, with an emphasis on satellite information. Our model captures the observed variability of the constituents examined in most cases, but with substantial underestimates in boreal regions. The strongest interannual variability on a global scale is found for carbon monoxide (~10% for its global annual burden), while the lowest is found for tropospheric ozone (~1% for its global annual burden). Regionally, aerosol optical depth shows the largest variability which exceeds 50%. Areas of strong variability of both aerosols and CO include the tropical land regions (especially Equatorial Asia and South America) and northern high latitudes, while even regions in the northern midlatitudes experience substantial interannual variability of aerosols. Ozone variability peaks over equatorial Asia in boreal autumn, partly due to varying biomass burning emissions, and over the western and central Pacific in the rest of the year, mainly due to meteorological fluctuations. We find that biomass burning emissions are almost entirely responsible for global CO interannual variability, and similarly important for OH variability. The same is true for global and regional aerosol variability, especially when not taking into account dust and sea-salt particles. We show that important implications can arise from such interannual influences for regional climate and air quality.

  10. Airborne measurements of different trace gases during the AROMAT-2 campaign with an Avantes spectrometer

    NASA Astrophysics Data System (ADS)

    Bösch, Tim; Meier, Andreas; Schönhardt, Anja; Peters, Enno; Richter, Andreas; Ruhtz, Thomas; Burrows, John

    2016-04-01

    Differential Optical Absorption Spectroscopy (DOAS) is a well-known, versatile, and frequently used technique for the analysis of trace gases within the atmosphere. Although DOAS has been used for several decades, airborne DOAS has become more popular during the last years because of the possibility of measuring in high lateral resolutions with the help of imaging instruments. Here, we present results of the AROMAT-2 campaign in Romania in summer 2015. The introduced measurements were taken using a nadir viewing Avantes spectrometer on board of a Cessna aircraft which flew over Bucharest and the Turceni power plant in Romania. The instrument covers the wavelength region of 287 - 551nm at a spectral resolution of 0.13nm and has a temporal resolution of 0.5s, translating to about 450m in flight direction at 3000m flight attitude. The field of view of the instrument was set to 8.1 degrees, resulting in a pixel size across track of about 420m. Compared to the imaging DOAS instrument AirMAP which was also operated from the aircraft, the signal to noise ratio of the simple nadir viewing spectrometer is slightly better, which allows an analysis of less abundant species and interesting spectral features. The results show a day-to-day variation of NO2 over the city of Bucharest as well as spectral features over lakes in the city, which can be attributed to algae. Furthermore, we were able to measure large emission plumes of NO2 and SO2 over the Turceni power plant, which could be observed over long spatial distances. In addition, the results from the Avantes instrument were used for comparison with measurements of the imaging spectrometer AirMAP and good agreement was found, providing independent verification of the imager data.

  11. Carbon Dioxide Information Analysis Center and World Data Center for Atmospheric Trace Gases Fiscal Year 2000 Annual Report

    SciTech Connect

    Cushman, R.M.

    2001-11-15

    The Carbon Dioxide Information Analysis Center (CDIAC), which includes the World Data Center (WDC) for Atmospheric Trace Gases, is the primary global change data and information analysis center of the U.S. Department of Energy (DOE). More than just an archive of data sets and publications, CDIAC has, since its inception in 1982, enhanced the value of its holdings through intensive quality assurance, documentation, and integration. Whereas many traditional data centers are discipline-based (for example, meteorology or oceanography), CDIAC's scope includes potentially anything and everything that would be of value to users concerned with the greenhouse effect and global climate change, including concentrations of carbon dioxide (CO{sub 2}) and other radiatively active gases in the atmosphere; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; emissions of CO{sub 2} and other trace gases to the atmosphere; long-term climate trends; the effects of elevated CO{sub 2} on vegetation; and the vulnerability of coastal areas to rising sea levels.

  12. The tropical forest and fire emissions experiment: Trace gases emitted by smoldering logs and dung from deforestation and pasture fires in Brazil

    NASA Astrophysics Data System (ADS)

    Christian, Ted J.; Yokelson, Robert J.; Carvalho, JoãO. A.; Griffith, David W. T.; Alvarado, Ernesto C.; Santos, José C.; Neto, Turibio Gomes Soares; Veras, Carlos A. Gurgel; Hao, Wei Min

    2007-09-01

    Earlier work showed that Amazonian biomass burning produces both lofted and initially unlofted emissions in large amounts. A mobile, Fourier transform infrared spectrometer (FTIR) measured the unlofted emissions of 17 trace gases from residual smoldering combustion (RSC) of logs as part of the Tropical Forest and Fire Emissions Experiment (TROFFEE) during the 2004 Amazonian dry season. The RSC emissions were highly variable and the few earlier RSC measurements lay near the high end of combustion efficiency observed in this study. Fuel consumption by RSC was ˜5% of total for a planned deforestation fire. Much regional RSC probably occurs in the residual woody debris burned during pasture maintenance fires. RSC could increase estimated total fire emissions for the Amazon region by 20-50% for several important VOC. FTIR emissions measurements of burning dung (in a pasture) showed high emission ratios for acetic acid and ammonia to CO (6.6 ± 3.4% and 8.9 ± 2.1%). Large emissions of nitrogen containing trace gases from burning dung and crop waste could mean that biomass burning in India produces more particle mass than previously assumed. Measurements of late-stage kiln emissions suggested that VOC/CO may increase as carbonization is extended. A cook stove emitted many VOC and NH3 far outside the range observed for open wood cooking fires. Enclosed/vented cooking stoves may change the chemistry of the smoke that is emitted.

  13. Summer 2009 wildfires in Portugal: Emission of trace gases and aerosol composition

    NASA Astrophysics Data System (ADS)

    Alves, Célia; Vicente, Ana; Nunes, Teresa; Gonçalves, Cátia; Fernandes, Ana Patrícia; Mirante, Fátima; Tarelho, Luís; Sánchez de la Campa, Ana M.; Querol, Xavier; Caseiro, Alexandre; Monteiro, Cristina; Evtyugina, Margarita; Pio, Casimiro

    2011-01-01

    In summer 2009, emissions of trace gases and aerosols from several wildfires occurring in Portugal were sampled. A portable high-volume sampler was used to collect sequentially, on quartz fibre filters, coarse (PM 2.5-10) and fine (PM 2.5) smoke particles. Tedlar air sampling bags have been used for complementary chemical characterisation of the gaseous phase. The carbonaceous content (elemental and organic carbon, EC/OC) of particulate matter was analysed by a thermal-optical transmission technique. The levels of almost 50 elements were quantified by inductively coupled plasma-mass spectrometry. The water-soluble ions were obtained by ion chromatography. Emission factors of species that are favoured by the smouldering phase (e.g. CO) were above the values reported in the literature for biomass burning in other ecosystems. The CO emission factors were 231 ± 117 g kg -1 biomass (dry basis) burned. Emissions of compounds that are promoted in fresh plumes and during the flaming phase, such as CO 2, were generally lower than those proposed for savannah and tropical forest fires. The CO 2 emission factors ranged from about 1000 to 1700 g kg -1. Total hydrocarbons, PM 2.5, PM 10 and OC presented variable emissions, but in general substantially higher than values reported for wildfires in African and Amazonian biomes. The emission factors obtained in Portugal were as follows (in g kg -1 biomass, dry basis): 6-350 for total hydrocarbons, 0.5-42 for PM 2.5, 1-60 for PM 10, and 0.2-42 for OC (in PM 10). The organic carbon-to-elemental carbon ratios measured in the present study largely exceeded those obtained by other researchers. The aerosol mass was dominated by organic matter (OC/PM 2.5 = 50 ± 18%, OC/PM 2.5-10 = 36 ± 18%). The metal elements represented, on average, 1.23 and 0.91%, while the measured water-soluble ions accounted for 2.6 and 2.1% of the PM 2.5 and PM 2.5-10 mass, respectively. Carbonates accounted for 0.15-3.1% (average = 0.83%) of PM 2.5-10. The

  14. Black carbon and trace gases over South Asia: Measurements and Regional Climate model simulations

    NASA Astrophysics Data System (ADS)

    Bhuyan, Pradip; Pathak, Binita; Parottil, Ajay

    2016-07-01

    Trace gases and aerosols are simulated with 50 km spatial resolution over South Asian CORDEX domain enclosing the Indian sub-continent and North-East India for the year 2012 using two regional climate models RegCM4 coupled with CLM4.5 and WRF-Chem 3.5. Both models are found to capture the seasonality in the simulated O3 and its precursors, NOx and CO and black carbon concentrations together with the meteorological variables over the Indian Subcontinent as well as over the sub-Himalayan North-Eastern region of India including Bangladesh. The model simulations are compared with the measurements made at Dibrugarh (27.3°N, 94.6°E, 111 m amsl). Both the models are found to capture the observed diurnal and seasonal variations in O3 concentrations with maximum in spring and minimum in monsoon, the correlation being better for WRF-Chem (R~0.77) than RegCM (R~0.54). Simulated NOx and CO is underestimated in all the seasons by both the models, the performance being better in the case of WRF-Chem. The observed difference may be contributed by the bias in the estimation of the O3 precursors NOx and CO in the emission inventories or the error in the simulation of the meteorological variables which influences O3 concentration in both the models. For example, in the pre-monsoon and winter season, the WRF-Chem model simulated shortwave flux overestimates the observation by ~500 Wm-2 while in the monsoon and post monsoon season, simulated shortwave flux is equivalent to the observation. The model predicts higher wind speed in all the seasons especially during night-time. In the post-monsoon and winter season, the simulated wind pattern is reverse to observation with daytime low and night-time high values. Rainfall is overestimated in all the seasons. RegCM-CLM4.5 is found to underestimate rainfall and other meteorological parameters. The WRF-Chem model closely captured the observed values of black carbon mass concentrations during pre-monsoon and summer monsoon seasons, but

  15. Characteristics of aerosol particles and trace gases in ship exhaust plumes

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.; Borrmann, S.

    2011-12-01

    Gaseous and particulate matter from marine vessels gain increasing attention due to their significant contribution to the anthropogenic burden of the atmosphere, implying the change of the atmospheric composition and the impact on local and regional air quality and climate (Eyring et al., 2010). As ship emissions significantly affect air quality of onshore regions, this study deals with various aspects of gas and particulate plumes from marine traffic measured near the Elbe river mouth in northern Germany. In addition to a detailed investigation of the chemical and physical particle properties from different types of commercial marine vessels, we will focus on the chemistry of ship plumes and their changes while undergoing atmospheric processing. Measurements of the ambient aerosol, various trace gases and meteorological parameters using a mobile laboratory (MoLa) were performed on the banks of the Lower Elbe which is passed on average, daily by 30 ocean-going vessels reaching the port of Hamburg, the second largest freight port of Europe. During 5 days of sampling from April 25-30, 2011 170 commercial marine vessels were probed at a distance of about 1.5-2 km with high temporal resolution. Mass concentrations in PM1, PM2.5 and PM10 and number as well as PAH and black carbon (BC) concentrations in PM1 were measured; size distribution instruments covered the size range from 6 nm up to 32 μm. The chemical composition of the non-refractory aerosol in the submicron range was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase species analyzers monitored various trace gas concentrations in the air and a weather station provided meteorological parameters. Additionally, a wide spectrum of ship information for each vessel including speed, size, vessel type, fuel type, gross tonnage and engine power was recorded via Automatic Identification System (AIS) broadcasts. Although commercial marine vessels powered by diesel engines consume high

  16. Amplification of trace amounts of nucleic acids

    DOEpatents

    Church, George M.; Zhang, Kun

    2008-06-17

    Methods of reducing background during amplification of small amounts of nucleic acids employ careful analysis of sources of low level contamination. Ultraviolet light can be used to reduce nucleic acid contaminants in reagents and equipment. "Primer-dimer" background can be reduced by judicious design of primers. We have shown clean signal-to-noise with as little as starting material as one single human cell (.about.6 picogram), E. coli cell (.about.5 femtogram) or Prochlorococcus cell (.about.3 femtogram).

  17. Application of ion chemistry and the SIFT technique to the quantitative analysis of trace gases in air and on breath

    NASA Astrophysics Data System (ADS)

    Smith, David; Španěl, Patrik

    Our major objective in this paper is to describe a new method we have developed for the analysis of trace gases at partial pressures down to the ppb level in atmospheric air, with special emphasis on the detection and quantification of trace gases on human breath. It involves the use of our selected ion flow tube (Sift) technique which we previously developed and used extensively for the study of gas phase ionic reactions occurring in ionized media such as the terrestrial atmosphere and interstellar gas clouds. Before discussing this analytical technique we describe the results of our very recent Sift and flowing afterglow (FA) studies of the reactions of the H3O+ and OH- ions, of their hydrates H3O+(H2O)1,2,3 and OH- (H2O)1,2, and of NO+ and O2+, with several hydrocarbons and oxygen-bearing organic molecules, studies that are very relevant to our trace gas analytical studies. Then follows a detailed discussion of the application of our Sift technique to trace gas analysis, after which we present some results obtained for the analyses of laboratory air, the breath of a healthy non-smoking person, the breath of a person who regularly smokes cigarettes, the complex vapours emitted by banana and onion, and the molecules present in a butane/air flame. We show how the quantitative analysis of breath can be achieved from only a single exhalation and in real time (the time response of the instrument is only about 20 ms). We also show how the time variation of breath gases over long time periods can be followed, using the decay of ethanol on the breath after the ingestion of distilled liquor as an example, yet simultaneously following several other trace gases including acetone and isoprene which are very easily detected on the breath of all individuals because of their relatively high partial pressures (typically 100 to 1000 ppb). The breath of a smoker is richer in complex molecules, some nitrogen containing organics apparently being very evident at the 5 to 50 ppb level

  18. Low to middle tropospheric profiles and biosphere/troposphere fluxes of acidic gases in the summertime Canadian taiga

    NASA Technical Reports Server (NTRS)

    Klemm, O.; Talbot, R. W.; Fitzgerald, D. R.; Klemm, K. I.; Lefer, B. L.

    1994-01-01

    We report features of acidic gases in the troposphere from 9 to 5000 m altitude above ground over the Canadian taiga in the summer of 1990. The measurements were conducted at a 30-m meteorological tower and from the NASA Wallops Electra aircraft as part of the joint U.S.-Canadian Arctic Boundary Layer Expedition (ABLE) 3B Northern Wetland Studies (NOWES). We sampled air for acidic gases using the mist chamber collector coupled with subsequent analysis using ion chromatography. At the tower we collected samples at two heights during a 13-day period, including diurnal studies. Using eddy flux and profile data, we estimated the biosphere/troposphere fluxes of nitric, formic, and acetic acids and sulfur dioxide. For the organic acids, emissions from the taiga in the afternoon hours and deposition during the predawn morning hours were observed. The flux intensities alone were however not high enough to explain the observed changes in mixing ratios. The measured deposition fluxes of nitric acid were high enough to have a significant influence on its mixing ratio in the boundary layer. On three days we measured vertical profiles of nitric, formic, and acetic acids through the lower to midtroposphere. We found that the chemical composition of the troposphere was extremely heterogenous. Pronounced layers of polluted air were readily apparent from our measurements. Local photochemical production and episodic long-range transport of trace components, originating from biomass burning and possibly industrial emissions, appear to have a strong influence on the composition of the troposphere and biosphere/troposphere fluxes of acidic gases at this site.

  19. Analysis of the horizontal distributions of trace gases and aerosols in summer 2013 during the MADCAT campaign in Mainz, Germany

    NASA Astrophysics Data System (ADS)

    Remmers, Julia; Beirle, Steffen; Wagner, Thomas

    2016-04-01

    With the MAX-DOAS technique it is possible to retrieve vertical profiles of trace gases and aerosols in the lower troposphere. Often these instruments monitor the atmosphere in one azimuthal direction only. Therefore horizontal variability is not resolved. Especially the comparison to satellite data close to strong emission sources (one main application of MAX-DOAS) is possibly biased. Many new developed MAX-DOAS instruments are capable to measure automatically in more than one azimuthal direction. During the MADCAT campaign in summer 2013 in Mainz, Germany, several instruments of this kind were operated simultaneously, which provides the opportunity to monitor the horizontal distribution of trace gases and aerosols with a high temporal and spatial resolution. The observed variation for different azimuth angles does not only reflect gradients in the trace gas concentrations, but also differences in the light path length, which is affected by sun and viewing geometry as well as aerosol distribution. Information about the aerosol profile, the total AOD and the phase function is gathered from a Ceilometer and an Aeronet sun photometer on the same site. To distinguish between the different effects comparisons with radiative transfer models are performed. Here especially the influence of the simplified model of Henyey-Greenstein phase functions against measured phase functions from Aeronet is investigated. Also the influence on the observed azimuthal gradients of different wind patterns and cloud conditions is studied.

  20. Oil and gas exploration system and method for detecting trace amounts of hydrocarbon gases in the atmosphere

    DOEpatents

    Wamsley, Paula R.; Weimer, Carl S.; Nelson, Loren D.; O'Brien, Martin J.

    2003-01-01

    An oil and gas exploration system and method for land and airborne operations, the system and method used for locating subsurface hydrocarbon deposits based upon a remote detection of trace amounts of gases in the atmosphere. The detection of one or more target gases in the atmosphere is used to indicate a possible subsurface oil and gas deposit. By mapping a plurality of gas targets over a selected survey area, the survey area can be analyzed for measurable concentration anomalies. The anomalies are interpreted along with other exploration data to evaluate the value of an underground deposit. The system includes a differential absorption lidar (DIAL) system with a spectroscopic grade laser light and a light detector. The laser light is continuously tunable in a mid-infrared range, 2 to 5 micrometers, for choosing appropriate wavelengths to measure different gases and avoid absorption bands of interference gases. The laser light has sufficient optical energy to measure atmospheric concentrations of a gas over a path as long as a mile and greater. The detection of the gas is based on optical absorption measurements at specific wavelengths in the open atmosphere. Light that is detected using the light detector contains an absorption signature acquired as the light travels through the atmosphere from the laser source and back to the light detector. The absorption signature of each gas is processed and then analyzed to determine if a potential anomaly exists.

  1. Process for the removal of acid forming gases from exhaust gases

    DOEpatents

    Chang, Shih-Ger; Liu, David K.

    1992-01-01

    Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorus preferably in a wet scrubber. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. are attractive. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, 100% of the by-products created are usable, and close to 100% of the NO or NO and SO.sub.2 can be removed in an economic fashion.

  2. Process for the removal of acid forming gases from exhaust gases

    DOEpatents

    Chang, S.G.; Liu, D.K.

    1992-11-17

    Exhaust gases are treated to remove NO or NO[sub x] and SO[sub 2] by contacting the gases with an aqueous emulsion or suspension of yellow phosphorus preferably in a wet scrubber. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50 C is attractive. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO[sub x] and SO[sub 2], alkalis that are used for flue gas desulfurization are preferred. With this process, 100% of the by-products created are usable, and close to 100% of the NO or NO[sub x] and SO[sub 2] can be removed in an economic fashion. 9 figs.

  3. Radiolysis gases from nitric acid solutions containing HSA and HAN

    SciTech Connect

    Smith, J.R.

    1994-10-28

    The concentration of hydrogen (H{sub 2}) in the radiolytically produced off-gas from 2.76-4.25M HNO{sub 3}/PU solutions has been found to be greatly reduced in the presence of sulfamic acid (HSA) and hydroxylamine nitrate (HAN). The H{sub 2} concentration ([H{sub 2}]) is reduced from 35 percent to about 4 percent by dilution caused from an increase in the production rates of nitrogen (N{sub 2}), nitrous oxide (N{sub 2}O), and oxygen (O{sub 2}) gases. The generation rate of H{sub 2} was not affected by HSA or HAN giving a measured radiolytic yield, G(H{sub 2}), value of 0.201 molecules/100 eV for 2.765M NO{sub 3}{sup -} solution (a value of 0.213 is predicted from previous data). The G(H{sub 2}) values are dependent on the solution nitrate concentration ([NO{sub 3}{sup -}]). The generation rates of N{sub 2}, N{sub 2}O, and O{sub 2} are not dependent on the [NO{sub 3}{sup -}] in this narrow range, but are dependent on the presence of HSA and the concentration of HAN. The percentage [H{sub 2}] for the 2.5 to 3.0M NO{sub 3}{sup -} range expected in the off- from the FB-Line Pu{sup +3} Hold Tanks is conservatively estimated to be about 3.5 to 4.5 % for Pu + 3 solutions initially containing 0.023M HAN/0.165M HSA. The upper limit [H{sub 2}] may actually be about 4.1 % (4.3 % at 90 % confidence limits) but more {open_quotes}initial{close_quotes} off-gas rate data is needed at about 2.9M [NO{sub 3}{sup -}] in Pu{sup +3} solution for verification. Addition of ascorbic acid had no effect on the off-gas rate of Pu{sup +3} solutions containing HSA and NO{sub 3}{sup -} concentrations higher than those expected in the hold tanks. The maximum {open_quotes}hold time{close_quotes} for 50 grams/liter Pu{sup +3}/0.165M HSA/0.023M HAN/2.5-3.0M HNO{sub 3} solution is 20.3{+-}2.1 days. After this time the HSA initially present will become exhausted and the [H{sub 2}] will increase to 35 %. This hold time may be longer in [NO{sub 3}{sup -}] < 3.0M, but again more study is needed.

  4. Trace rare gases optical emission spectroscopy: nonintrusive method for measuring electron temperatures in low-pressure, low-temperature plasmas.

    PubMed

    Malyshev, M V; Donnelly, V M

    1999-11-01

    Trace rare gases optical emission spectroscopy (TRG-OES) is a new, nonintrusive method for determining electron temperatures (T(e)) and, under some conditions, estimating electron densities (n(e)) in low-temperature, low-pressure plasmas. The method is based on a comparison of atomic emission intensities from trace amounts of rare gases (an equimixture of He, Ne, Ar, Kr, and Xe) added to the plasma, with intensities calculated from a model. For Maxwellian electron energy distribution functions (EEDFs), T(e) is determined from the best fit of theory to the experimental measurements. For non-Maxwellian EEDFs, T(e) derived from the best fit describes the high-energy tail of the EEDF. This method was reported previously, and was further developed and successfully applied to several laboratory and commercial plasma reactors. It has also been used in investigations of correlations between high-T(e) and plasma-induced damage to thin gate oxide layers. In this paper, we provide a refined mechanism for the method and include a detailed description of the generation of emission from the Paschen 2p manifold of rare gases both from the ground state and through metastable states, a theoretical model to calculate the number density of metastables (n(m)) of the rare gases, a practical procedure to compute T(e) from the ratios of experimental-to-theoretical intensity ratios, a way to determine the electron density (n(e)), a discussion of the range of sensitivity of TRG-OES to the EEDF, and an estimate of the accuracy of T(e). The values of T(e) obtained by TRG-OES in a transformer-coupled plasma reactor are compared with those obtained with a Langmuir probe for a wide range of pressures and powers. The differences in T(e) from the two methods are explained in terms of the EEDF dependence on pressure.

  5. An automated dynamic chamber system for surface exchange measurement of non-reactive and reactive trace gases of grassland ecosystems

    NASA Astrophysics Data System (ADS)

    Pape, L.; Ammann, C.; Nyfeler-Brunner, A.; Spirig, C.; Hens, K.; Meixner, F. X.

    2009-03-01

    We present an automated dynamic chamber system which is optimised for continuous unattended flux measurements of multiple non-reactive and reactive trace gases on grassland ecosystems. Main design features of our system are (a) highly transparent chamber walls consisting of chemically inert material, (b) individual purging flow units for each chamber, and (c) a movable lid for automated opening and closing of the chamber. The purging flow rate was chosen high enough to keep the mean residence time of the chamber air below one minute. This guarantees a proven efficient mixing of the chamber volume and a fast equilibration after lid closing. The dynamic chamber system is able to measure emission as well as deposition fluxes of trace gases. For the latter case, the modification of the turbulent transport by the chamber (compared to undisturbed ambient conditions) is quantitatively described by a bulk resistance concept. Beside a detailed description of the design and functioning of the system, results of field applications at two grassland sites are presented. In the first experiment, fluxes of five trace gases (CO2, H2O, NO, NO2, O3) were measured simultaneously on small grassland plots. It showed that the dynamic chamber system is able to detect the characteristic diurnal cycles with a sufficient temporal resolution. The results also demonstrated the importance of considering the chemical source/sink in the chamber due to gas phase reactions for the reactive compounds of the NO-NO2-O3 triad. In a second field experiment, chamber flux measurements of CO2 and methanol were compared to simultaneous independent eddy covariance flux measurements on the field scale. The fluxes obtained with the two methods showed a very good agreement indicating a minimal disturbance of the chambers on the physiological activity of the enclosed vegetation.

  6. An automated dynamic chamber system for surface exchange measurement of non-reactive and reactive trace gases of grassland ecosystems

    NASA Astrophysics Data System (ADS)

    Pape, L.; Ammann, C.; Nyfeler-Brunner, A.; Spirig, C.; Hens, K.; Meixner, F. X.

    2008-08-01

    We present an automated dynamic chamber system which is optimised for continuous unattended flux measurements of multiple non-reactive and reactive trace gases on grassland ecosystems. Main design features of our system are (a) highly transparent chamber walls consisting of chemically inert material, (b) individual purging flow units for each chamber, and (c) a movable lid for automated opening and closing of the chamber. The purging flow rate was chosen high enough to keep the mean residence time of the chamber air below one minute. This guarantees a proven efficient mixing of the chamber volume and a fast equilibration after lid closing. The dynamic chamber system is able to measure emission as well as deposition fluxes of trace gases. For the latter case, the modification of the turbulent transport by the chamber (compared to undisturbed ambient conditions) is quantitatively described by a bulk resistance concept. Beside a detailed description of the design and functioning of the system, results of field applications at two grassland sites are presented. In the first experiment, fluxes of five trace gases (CO2, H2O, NO, NO2, O3) were measured simultaneously on small grassland plots. It showed that the dynamic chamber system is able to detect the characteristic diurnal cycles with a sufficient temporal resolution. The results also demonstrated the importance of considering the chemical source/sink in the chamber due to gas phase reactions for the reactive compounds of the NO-NO2-O3 triad. In a second field experiment, chamber flux measurements of CO2 and methanol were compared to simultaneous independent eddy covariance flux measurements on the field scale. The fluxes obtained with the two methods showed a very good agreement indicating a minimal disturbance of the chambers on the physiological activity of the enclosed vegetation.

  7. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania

    NASA Astrophysics Data System (ADS)

    Lawson, S. J.; Keywood, M. D.; Galbally, I. E.; Gras, J. L.; Cainey, J. M.; Cope, M. E.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Bentley, S. T.; Meyer, C. P.; Ristovski, Z.; Goldstein, A. H.

    2015-12-01

    (ΔO3 / ΔCO 0.001-0.074). A short-lived increase in NMOCs by a factor of 10 corresponded with a large CO enhancement, an increase of the NMOC / CO emission ratio (ER) by a factor of 2-4 and a halving of the BC / CO ratio. Rainfall on Robbins Island was observed by radar during this period which likely resulted in a lower fire combustion efficiency, and higher emission of compounds associated with smouldering. This highlights the importance of relatively minor meteorological events on BB emission ratios. Emission factors (EFs) were derived for a range of trace gases, some never before reported for Australian fires, (including hydrogen, phenol and toluene) using the carbon mass balance method. This provides a unique set of EFs for Australian coastal heathland fires. Methyl halide EFs were higher than EFs reported from other studies in Australia and the Northern Hemisphere which is likely due to high halogen content in vegetation on Robbins Island. This work demonstrates the substantial impact that BB plumes can have on the composition of marine air, and the significant changes that can occur as the plume interacts with terrestrial, aged urban and marine emission sources.

  8. Adsorption of humic acids and trace metals in natural waters

    NASA Technical Reports Server (NTRS)

    Leung, W. H.

    1982-01-01

    Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

  9. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    SciTech Connect

    Mazor, E.; Truesdell, A.H.

    1981-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He, /sup 40/Ar) and atmospheric noble gases (Ne, Ar, and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic helium and argon-40 formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 to 3%) and mixing with shallow cold water occurred (0 to 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 to 3% steam separation and complement other tracers, such as Cl or temperature, which are effective only beyond this range.

  10. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    USGS Publications Warehouse

    Mazor, E.; Truesdell, A.H.

    1984-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He and 40Ar) and atmospheric noble gases (Ne, Ar and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water that penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic He and 40Ar formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 - 30%) and mixing with shallow cold water occurred (0 - 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 - 3% steam separation and complement other tracers, such as C1 or temperature, which are effective only beyond this range. ?? 1984.

  11. Analysis of trace gases at ppb levels by proton transfer reaction mass spectrometry (PTR-MS)

    NASA Astrophysics Data System (ADS)

    Lindinger, W.; Hansel, A.

    1997-05-01

    A proton transfer reaction mass spectrometry (PTR-MS) system has been developed which allows for on-line measurements of trace gas components with concentrations as low as 1 ppb. The method is based on reactions of 0963-0252/6/2/004/img1 ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of medical applications by means of breath analysis, examples of environmental trace gas analysis and examples in the field of food chemistry demonstrate the wide applicability of the method.

  12. Carbon Dioxide Information Analysis Center and World Data Center-A for atmospheric trace gases: FY 1993 activities

    SciTech Connect

    Cushman, R.M.; Stoss, F.W. |

    1994-01-01

    During the course of a fiscal year, Oak Ridge National Laboratory`s Carbon Dioxide Information Analysis Center (CDIAC) distributes thousands of specialty publications-numeric data packages (NDPs), computer model packages (CMPs), technical reports, public communication publications, newsletters, article reprints, and reference books-in response to requests for information related to global environmental issues, primarily those pertaining to climate change. CDIAC`s staff also provide technical responses to specific inquiries related to carbon dioxide (CO{sub 2}), other trace gases, and climate. Hundreds of referrals to other researchers, policy analysts, information specialists, or organizations are also facilitated by CDIAC`s staff. This report provides an account of the activities accomplished by CDIAC (including World Data Center-A for Atmospheric Trace Gases) during the period October 1, 1992, to September 30, 1993. An organizational overview of CDIAC and its staff is supplemented by a detailed description of inquiries received and CDIAC`s response to those inquiries. An analysis and description of the preparation and distribution of NDPS, CMPS, technical reports, newsletters, fact sheets, specialty publications, and reprints are provided. Comments and descriptions of CDIAC`s information management systems, professional networking, and special bilateral agreements are also presented.

  13. MAX-DOAS measurements of atmospheric trace gases in Ny-Ålesund - Radiative transfer studies and their application

    NASA Astrophysics Data System (ADS)

    Wittrock, F.; Oetjen, H.; Richter, A.; Fietkau, S.; Medeke, T.; Rozanov, A.; Burrows, J. P.

    2004-06-01

    A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have been applied to this standard setup to use different lines of sight near to the horizon as additional light sources (MAX - multi axis). Results from measurements at Ny-Ålesund (79° N, 12° E) are presented and interpreted with the full-spherical radiative transfer model SCIATRAN. In particular, measurements of the oxygen dimer O4 which has a known column and vertical distribution in the atmosphere are used to evaluate the sensitivity of the retrieval to parameters such as multiple scattering, solar azimuth, surface albedo and refraction in the atmosphere and also to validate the radiative transfer model. As a first application, measurements of NO2 emissions from a ship lying in Ny-Ålesund harbour are presented. The results of this study demonstrate the feasibility of long term UV/vis multi axis measurement that can be used to derive not only column amounts of different trace gases but also some information on the vertical location of these absorbers.

  14. Atmos/Atlas 3 Infrared Profile Measurements of Trace Gases in The November 1994 Tropical and Subtropical Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Wang, P.-H.; Arduini, R. F.; Baum, B. A.; Minnis, P.; Minnis, P.; Goldman, A.; Abrams, M. C.; Zander, R.; Mahieu, E.; Mahieu, E.; Salawitch, R. J.; Michelsen, H. A.; Irion, F. W.; Newchurch, M. J.

    1998-01-01

    Vertical mixing ratio profiles of four relatively long-lives gases, HCN, C2H2, CO, and C2H6, have been retrieved from 0.01/cm resolution infrared solar occultation spectra recorded between latitudes of 5.3degN and 31.4degN. The observations were obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS) 3 shuttle flight, 3-12 November 1994. Elevated mixing ratios below the tropopause were measured for these gases during several of the occultations. The positive correlations obtained between the simultaneously measured mixing ratios suggest that the enhancements are likely the result of surface emissions, most likely biomass burning and/or urban industrial activities, followed by common injection via deep convective transport of the gases to the upper troposphere. The elevated levels of HCN may account for at least part of the "missing NO," in the upper troposphere. Comparisons of the observations with values measured during a recent aircraft campaign are presented.

  15. Long-term MAX-DOAS measurement of trace gases and aerosol in the Environmental Research Station Schneefernerhaus

    NASA Astrophysics Data System (ADS)

    Wang, Zhuoru; Hao, Nan; Hendrick, François; Van Roozendael, Michel; Holla, Robert; Valks, Pieter

    2016-04-01

    The Environmental Research Station Schneefernerhaus (Umwelt Forschungsstation Schneefernerhaus, UFS) is located immediately under the summit of Zugspitze (2962 m), the highest mountain of Germany, at a height of 2650 m. The UFS is a rare observation site in Germany with mostly clean and unpolluted air. It is ideal for both stratospheric composition measurements and trace gas measurements in the free-troposphere. It is optimal for detecting pollution events in the free-troposphere, which are indications of short- or long-range transport of air pollutants. A MAX-DOAS instrument has been working in the UFS since February 2011. With the zenith spectrum of each cycle used as the reference, the differential slant column densities (DSCDs) of trace gases are calculated from the spectra with Differential Optical Absorption Spectroscopy (DOAS) method. The DSCDs of both O4 and NO2 are calculated in two different wavelength intervals, 338-370 nm in the UV region and 440-490 nm in the VIS region. For HCHO and HONO, optimal fitting windows have been determined in the UV region. A retrieval algorithm, based on the radiative transfer model LIDORT and the optimal estimation technique, is used to provide information on the vertical profiles and vertical column densities (VCDs) of aerosol and trace gases. Meanwhile, zenith-sky radiance spectra during twilight hours are analyzed using DOAS method to derive the total vertical column densities (VCDs) of O3 and NO2. A zenith spectrum measured in the noon of a summer day was chosen as the reference spectrum. The slant column densities (SCDs) of O3 and NO2, which are the direct product of the DOAS analysis, are then converted into VCDs using the air mass factors (AMFs) derived by radiative transfer calculations. This work presents the results of the MAX-DOAS measurement in the UFS from 2012 to 2015, including aerosol (derived from O4 measurement), NO2, HCHO, and HONO, etc. The vertical profiles as well as the seasonal and diurnal variation

  16. [Dynamics of blood gases and acid-base balance in patients with carbon monoxide acute poisoning].

    PubMed

    Polozova, E V; Shilov, V V; Bogachova, A S; Davydova, E V

    2015-01-01

    Evaluation of blood gases and acid-base balance covered patients with carbon monoxide acute poisoning, in accordance with inhalation trauma presence. Evidence is that thermochemical injury of respiratory tract induced severe acid-base dysbalance remaining decompensated for a long time despite the treatment.

  17. Tracing the Complex Ice Cover Evolution of Lake Vida, Antarctica Through Noble Gases

    NASA Astrophysics Data System (ADS)

    Malone, J. L.; Castro, M. C.; Hall, C. M.; Doran, P. T.; Kenig, F.; McKay, C. P.

    2008-12-01

    Unlike other lakes in the McMurdo Dry Valleys in Antarctica, Lake Vida has a very thick (~19 m) ice cover and a liquid brine body of unusually high salinity (~245 g/L). Because noble gases (He, Ne, Ar, Kr and Xe) are conservative in nature, they can be used to understand physical processes taking place during ice formation (e.g., partitioning of noble gases between the ice and residual liquid, bubble formation at the ice-liquid interface) thus, providing information with respect to the temporal evolution of the dry valley lakes. In an attempt to constrain the conditions under which the atypical Lake Vida ice cover formed and evolved, we collected 19 ice samples along a vertical profile from the surface down to a depth of ~14 m as well as three liquid brine samples from briny ice at a depth of ~16 m for analysis of all noble gases. Our results show that the broad pattern of noble gas concentrations for the Lake Vida ice cover and associated brines is fundamentally different from that expected for air saturated water (ASW). Overall, ice samples are relatively enriched in He, slightly depleted in Ne, and strongly depleted in the heavier noble gases (Ar, Kr, Xe) with respect to ASW. By contrast, brine samples are very enriched in heavy noble gases. To understand the mechanisms responsible for the observed noble gas distribution and fractionation in the Lake Vida cover, a conceptual three-phase (ice, brine, bubbles) partition model was tested. The model allows the lighter noble gases (He and Ne) to reside interstitially in ice while Ar, Kr, and Xe are totally excluded, causing supersaturation in the residual liquid as freezing progresses and formation of gas bubbles occurs at the ice-liquid interface. These bubbles are subsequently incorporated into the ice. While the general noble gas enrichment and depletion patterns of the model are consistent with our brine and ice data, quantitative agreement with output values is not as good under similar model conditions (e

  18. Process for recovery of sulfur from acid gases

    DOEpatents

    Towler, Gavin P.; Lynn, Scott

    1995-01-01

    Elemental sulfur is recovered from the H.sub.2 S present in gases derived from fossil fuels by heating the H.sub.2 S with CO.sub.2 in a high-temperature reactor in the presence of a catalyst selected as one which enhances the thermal dissociation of H.sub.2 S to H.sub.2 and S.sub.2. The equilibrium of the thermal decomposition of H.sub.2 S is shifted by the equilibration of the water-gas-shift reaction so as to favor elemental sulfur formation. The primary products of the overall reaction are S.sub.2, CO, H.sub.2 and H.sub.2 O. Small amounts of COS, SO.sub.2 and CS.sub.2 may also form. Rapid quenching of the reaction mixture results in a substantial increase in the efficiency of the conversion of H.sub.2 S to elemental sulfur. Plant economy is further advanced by treating the product gases to remove byproduct carbonyl sulfide by hydrolysis, which converts the COS back to CO.sub.2 and H.sub.2 S. Unreacted CO.sub.2 and H.sub.2 S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H.sub.2 and CO, which has value either as a fuel or as a chemical feedstock and recovers the hydrogen value from the H.sub.2 S.

  19. CARBON TRACE GASES IN LAKE AND BEAVER POND ICE NEAR THOMPSON, MANITOBA, CANADA

    EPA Science Inventory

    Concentrations of CO2, CO, and CH4 were measured in beaver pond and lake ice in April 1996 near Thompson, Manitoba to derive information on possible impacts of ice melting on corresponding atmospheric trace gas concentrations. CH4 concentrations in beaver pond and lake ice ranged...

  20. Origin, speciation, and fluxes of trace-element gases at Augustine volcano, Alaska: Insights into magma degassing and fumarolic processes

    SciTech Connect

    Symonds, R.B.; Rose, W.I. ); Reed, M.H. )

    1992-02-01

    Thermochemical modeling predicts that trace elements in the Augustine gas are transported from near-surface magma as simple chloride, oxychloride, sulfide, and elemental gas species. However, Si, Ca, Al, Mg, Ti, V, and Cr are actually more concentrated in solids, beta-quartz (SiO{sub 2}), wollastonite (CaSiO{sub 3}), anorthite (CaAl{sub 2}Si{sub 2}O{sub 8}), diopside (CaMgSi{sub 2}O{sub 6}), sphene (CaTiSiO{sub 5}), V{sub 2}O{sub 3}(c), and Cr{sub 2}O{sub 3}(c), respectively, than in their most abundant gaseous species, SiF{sub 4}, CaCl{sub 2}, AlF{sub 2}O, MgCl{sub 2}, TiCl{sub 4}, VOCl{sub 3}, and CrO{sub 2}Cl{sub 2}. Using the calculated distribution of gas species and the COSPEC SO{sub 2} fluxes, the authors have estimated the emission rates for many species. Such forecasts could be useful to evaluate the effects of these trace species on atmospheric chemistry. Because of the high volatility of metal chlorides, the extremely HCl-rich Augustine volcanic gases are favorable for transporting metals from magma. Thermochemical modeling shows that equilibrium degassing of magma near 870C can account for the concentrations of Fe, Na, K, Mn, Cu, Ni, and part of the Mg in the gases escaping from the dome fumaroles on the 1986 lava dome. Nonvolatile elements in the gas condensates came from eroded rock particles that dissolved in the authors' samples or, for Si, from contamination from the silica sampling tube. Erosion is more prevalent in the pyroclastic flow fumaroles than in the summit vents, reflecting physical differences in the fumarole walls: ash vs. lava. Trace element contents of volcanic gases show enormous variability because of differences in the intensive parameters of degassing magma and variable amounts of wall rock erosion in volcanic fumaroles.

  1. Origin, speciation, and fluxes of trace-element gases at Augustine volcano, Alaska: Insights into magma degassing and fumarolic processes

    NASA Astrophysics Data System (ADS)

    Symonds, Robert B.; Reed, Mark H.; Rose, William I.

    1992-02-01

    Thermochemical modeling predicts that trace elements in the Augustine gas are transported from near-surface magma as simple chloride (NaCl, KCl, FeCl 2, ZnCl 2, PbCl 2, CuCl, SbCl 3, LiCl, MnCl 2, NiCl 2, BiCl, SrCl 2), oxychloride (MoO 2Cl 2), sulfide (AsS), and elemental (Cd) gas species. However, Si, Ca, Al, Mg, Ti, V, and Cr are actually more concentrated in solids, beta-quartz (SiO 2), wollastonite (CaSiO 3), anorthite (CaAl 2Si 2O 8), diopside (CaMgSi 2O 6), sphene (CaTiSiO 5), V 2O 3(c), and Cr 2O 3(c), respectively, than in their most abundant gaseous species, SiF 4, CaCl 2, AlF 2O, MgCl 2 TiCl 4, VOCl 3, and CrO 2Cl 2. These computed solids are not degassing products, but reflect contaminants in our gas condensates or possible problems with our modeling due to "missing" gas species in the thermochemical data base. Using the calculated distribution of gas species and the COSPEC SO 2 fluxes, we have estimated the emission rates for many species (e.g., COS, NaCl, KCl, HBr, AsS, CuCl). Such forecasts could be useful to evaluate the effects of these trace species on atmospheric chemistry. Because of the high volatility of metal chlorides (e.g., FeCl 2, NaCl, KCl, MnCl 2, CuCl), the extremely HCl-rich Augustine volcanic gases are favorable for transporting metals from magma. Thermochemical modeling shows that equilibrium degassing of magma near 870°C can account for the concentrations of Fe, Na, K, Mn, Cu, Ni and part of the Mg in the gases escaping from the dome fumaroles on the 1986 lava dome. These calculations also explain why gases escaping from the lower temperature but highly oxidized moat vents on the 1976 lava dome should transport less Fe, Na, K, Mn and Ni, but more Cu; oxidation may also account for the larger concentrations of Zn and Mo in the moat gases. Nonvolatile elements (e.g., Al, Ca, Ti, Si) in the gas condensates came from eroded rock particles that dissolved in our samples or, for Si, from contamination from the silica sampling tube. Only a

  2. Re-Evaluation of the Lifetimes of Ozone-Depleting Substances and Related Trace Gases

    NASA Astrophysics Data System (ADS)

    Reimann, Stefan; Ko, Malcolm; Newman, Paul; Strahan, Susan

    2013-04-01

    Estimating the average lifetime of a chemical in the atmosphere is crucial to understanding their current and future atmospheric concentrations. Furthermore, for ozone depleting substances (ODSs) and greenhouse gases information on their lifetimes are of paramount importance for obtaining estimates for ozone depletion and climate forcing. Because the lifetimes of ODSs are also used to predict how the future concentrations change with emissions, they also have implications on policy decisions for limiting future release of hydrochlorofluorocarbons (HCFCs) and other replacement compounds under the Montreal Protocol. During the last 25 years, various methods have been used to derive lifetimes of ODSs and values have changed accordingly. Within the last several years evidence is growing that the lifetimes of certain ODSs are possibly somewhat longer than published values. The "Lifetime of halogen source gases" activity under the World Climate Research Programme (WCRP)/Stratospheric Processes And their Role in Climate (SPARC) project has convened a working group to re-evaluate these ODS lifetimes. The goal was to estimate the numerical values for lifetimes and their uncertainties, and to quantify how the values may depend on factors such as the use of different lifetime definitions (e.g. steady-state/instantaneous lifetimes) and changing climate. First results of the report will be shown and implications will be discussed.

  3. Emission of climate-relevant trace gases and succession of microbial communities during open-windrow composting

    SciTech Connect

    Hellmann, B.; Zelles, L.; Palojaervi, A.; Bai, Q.

    1997-03-01

    Municipal solid-waste composting is a process of increasing importance, based primarily on augmentation of microbial activity. The composting of organic matter leads not only to a reduction in waste but a sensible recycling of residuals to their origin. Carbon dioxide derived from plant matter degradation does not contribute to global warming. However, emitted nitrous oxide and methane molecules contribute to the enhancement of the greenhouse effect. This study determined a wide variety of microbial properties during the composting processes at a whole windrow level and quantified the emission rates of the climate relevant trace gases, carbon dioxide, nitrous oxide and methane during the course of maturation of a compost row. 47 refs., 6 figs., 1 tab.

  4. Note: A dual temperature closed loop batch reactor for determining the partitioning of trace gases within CO2-water systems.

    PubMed

    Warr, Oliver; Rochelle, Christopher A; Masters, Andrew J; Ballentine, Christopher J

    2016-01-01

    An experimental approach is presented which can be used to determine partitioning of trace gases within CO2-water systems. The key advantages of this system are (1) The system can be isolated with no external exchange, making it ideal for experiments with conservative tracers. (2) Both phases can be sampled concurrently to give an accurate composition at each phase at any given time. (3) Use of a lower temperature flow loop outside of the reactor removes contamination and facilitates sampling. (4) Rapid equilibration at given pressure/temperature conditions is significantly aided by stirring and circulating the water phase using a magnetic stirrer and high-pressure liquid chromatography pump, respectively. PMID:26827363

  5. Emissions of Trace Gases and Particles from Two Ships in the Southern Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Sinha, Parikhit; Hobbs, Peter V.; Yokelson, Robert J.; Christian, Ted J.; Kirchstetter, Thomas W.; Bruintjes, Roelof

    2003-01-01

    Measurements were made of the emissions of particles and gases from two diesel-powered ships in the southern Atlantic Ocean off the coast of Namibia. The measurements are used to derive emission factors from ships of three species not reported previously, namely, black carbon, accumulation-mode particles, and cloud condensation nuclei (CCN), as well as for carbon dioxide, carbon monoxide (CO), methane (CH4), non-methane hydrocarbons, sulfur dioxide (SO2), nitrogen oxides (NOx), and condensation nuclei. The effects of fuel grade and engine power on ship emissions are discussed. The emission factors are combined with fuel usage data to obtain estimates of global annual emissions of various particles and gases from ocean-going ships. Global emissions of black carbon, accumulation- mode particles, and CCN from ocean-going ships are estimated to be 19-26 Gg yr(sup -1), (4.4-6.1) x 10(exp 26) particles yr(sup -1), and (1.0-1.5) x l0(exp 26) particles yr(sup -1), respectively. Black carbon emissions from ocean-going ships are approximately 0.2% of total anthropogenic emissions. Emissions of NOx and SO2 from ocean-going ships are approximately 10-14% and approximately 3-4%, respectively, of the total emissions of these species from the burning of fossil fuels, and approximately 40% and approximately 70%, respectively, of the total emissions of these species from the burning of biomass. Global annual emissions of CO and CH4 from ocean-going ships are approximately 2% and approximately 2-5%, respectively, of natural oceanic emissions of these species.

  6. Photoacoustic monitoring of trace gases by use of a diode-based difference frequency laser source.

    PubMed

    Fischer, C; Sigrist, M W; Yu, Q; Seiter, M

    2001-10-15

    We present a compact mid-infrared laser spectrometer for trace-gas monitoring. Difference frequency generation in periodically poled LiNbO(3) is used as laser source, yielding a tuning range 3.2-3.7mum at a linewidth of 154 MHz. The relatively high average power of 3 to 5 mW favors detection with a small resonant photoacoustic gas cell. Measurements of methane yield a detection limit in the low parts in 10(6) by volume concentration range. PMID:18049679

  7. Vapour and acid components separation from gases by membranes principles and engineering approach to membranes development

    NASA Astrophysics Data System (ADS)

    Kagramanov, G. G.; Storojuk, I. P.; Farnosova, E. N.

    2016-09-01

    The modern commercially available polymer membranes and membrane modules for purification of gases, containing acid components, simultaneously with dehumidification of treated gas streams, were developed and commercialized in the very end of XXth century. The membranes basic properties - selectivity (separation factor) and permeation flow rates - are relatively far from satisfying the growing and modern-scale industrial need in purification technologies and corresponding equipments. The attempt to formulate the basic principles, scientific and engineering approaches to the development of prospective membranes for the purification of gases, especially such as natural and oil gases, from acid components, simultaneously with drying them, was being made. For this purpose the influence of various factors - polymer nature, membrane type, structure, geometrical and mass-transfer characteristics, etc. - were studied and analyzed in order to formulate the basic principles and demands for development of membranes, capable to withstand successfully the sever conditions of exploitation.

  8. Using FLEXPART-WRF to Identify Source Regions Influencing Arctic Trace Gases and Aerosols During the Summer 2014 NETCARE Campaign

    NASA Astrophysics Data System (ADS)

    Thomas, J. L.

    2015-12-01

    In July and August 2014 the Canadian Network on Aerosols and Climate: Addressing Key Uncertainties in Remote Canadian Regions (NETCARE) project conducted aircraft and ship based campaigns with the goal of identifying both emissions and atmospheric processes influencing Arctic trace gas and aerosol concentrations. The aircraft campaign was conducted using the Alfred Wegener Institute's POLAR 6 aircraft (based in Resolute Bay, Canada) and the ship based campaign was conducted onboard the CCGS Amundsen (icebreaker and Arctic Ocean research vessel). Here, we use the Weather Research and Forecasting Model (WRF) to study meteorology and transport patterns that influence airmasses sampled during the aircraft campaign (5-21 July 2012) and research Legs 1a and 1b for Amundsen (1a: 8 - 24 July Quebec City to Resolute and 24 July - 14 August Resolute to Kugluktuk). The FLEXible PARTicle dispersion model driven by WRF meteorology (FLEXPART-WRF) run in backwards mode is used to study source regions that influenced enhanced concentrations in trace gases including DMS and NH3 as well as aerosols. Links between biomass burning in Northern Canada and measurements during the campaign are discussed. Finally FLEXPART-WRF run in forward mode is used to study links between shipping emissions from the Amundsen and enhanced pollution sampled by the POLAR 6 aircraft when both were operating in the same region of Lancaster Sound during the campaigns.

  9. Exposure assessment of oxidant gases and acidic aerosols

    SciTech Connect

    Lioy, P.J.

    1989-01-01

    Clearly the presence of high ozone and acidic species in North America is primarily dependent upon photochemical air pollution. Evidence shows, however, that high acid exposures may occur in specific types of areas of high sulfur fuel use during the winter. At the present time, our concerns about exposure to local populations and regional populations should be directed primarily toward the outdoor activity patterns of individuals in the summer, and how those activity patterns relate to the location, duration, and concentrations of ozone and acid aerosol in photochemical air pollution episodes. Lioy Dyba and Mage et al have examined the activity patterns of children in summer camps. Because they spend more time outside than the normal population, these children form an important group of exercising individuals subject to photochemical pollution exposures. The dose of ozone inhaled by the children in the two camps was within 50% and 25% of the dose inhaled by adults in controlled clinical situations that produced clinically significant decrements in pulmonary function and increased the symptoms after 6.6 hr exposure in a given day. The chamber studies have used only ozone, whereas in the environment this effect may be enhanced by the presence of a complex mixture. The work of Lioy et al in Mendham, New Jersey found that hydrogen ion seemed to play a role in the inability of the children to return immediately to their normal peak expiratory flow rate after exposure. The camp health study conducted in Dunsville, Ontario suggested that children participating in a summer camp where moderate levels of ozone (100 ppb) but high levels of acid (46 micrograms/m3) occurred during an episode had a similar response. Thus, for children or exercising adults who are outdoors for at least one hour or more during a given day, the presence and persistence of oxidants in the environment are of particular concern. 63 references.

  10. Trapping, chemistry, and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008

    NASA Astrophysics Data System (ADS)

    Rauthe-Schöch, Armin; Baker, Angela K.; Schuck, Tanja J.; Brenninkmeijer, Carl A. M.; Zahn, Andreas; Hermann, Markus; Stratmann, Greta; Ziereis, Helmut; van Velthoven, Peter F. J.; Lelieveld, Jos

    2016-03-01

    The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10-12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region (which so far has mostly been observed from satellites) using the broad suite of trace gases and aerosol particles measured by CARIBIC. Elevated levels of a variety of atmospheric pollutants (e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles, and several volatile organic compounds) were recorded. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with distinct latitudinal patterns of trace gases during the entire monsoon period. Using the CARIBIC trace gas and aerosol particle measurements in combination with the Lagrangian particle dispersion model FLEXPART, we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. The trajectory calculations indicate that these air masses originated mainly from South Asia and mainland Southeast Asia. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 90-95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were systematically younger (less than 7 days) and the air masses were mostly in an ozone-forming chemical mode. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories, several receptor regions were identified. In addition to predominantly westward transport, we found evidence for

  11. Quantum cascade laser based sensor for in situ and real time atmospheric trace gases (CO and N2O) measurements

    NASA Astrophysics Data System (ADS)

    Li, Jingsong; Parchatka, Uwe; Fischer, Horst

    2013-04-01

    In addition to the primary greenhouse gases carbon dioxide (CO2) and methane (CH4), several other atmospheric trace gases are radiatively active, and thereby can also contribute to a greenhouse warming of the lower atmosphere directly or indirectly. Nitrous oxide (N2O) is a greenhouse gas with a global warming potential about 200-300 times that of CO2. Carbon monoxide (CO) is not considered a direct greenhouse gas, mostly because it does not absorb terrestrial thermal IR energy strongly enough. However, CO plays an important role in the oxidative chemistry of Earth's atmosphere, since it is a key trace gas for controlling the budget and distribution of the hydroxyl (OH) radical, which exerts a controlling influence on the gas phase chemistry of many atmospheric species [1]. Therefore, there is a critical need to identify sources and sinks of N2O and CO in order to better understand their impact on global climate change [2]. We present a fast, compact, and precise sensor based-on a novel thermoelectrically (TE) cooled quantum cascade laser (QCL) operating at near-room temperature in CW (continuous-wave) mode for simultaneous detection of atmospheric N2O and CO. The technique is based on atmospheric absorption of these trace species in the mid-infrared region near 4.56 µm, using a single QC laser source and two TE-cooled infrared detectors. Wavelength modulation spectroscopy with second harmonic detection technique in conjunction with a compact multi-pass absorption cell has been employed to demonstrate highly sensitive and precise measurements. CO and N2O at ambient concentration levels are detected simultaneously with a high temporal response (< 1s). Preliminary results (Laboratory investigation and field application) of the sensor's performance will be presented. This completely TE-cooled system shows the capability of long-term, unattended and continuous operation at room temperature without complicated cryogenic cooling [3]. [1] J. A. Logan, M. J. Prather, S. C

  12. Trapping, chemistry and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008

    NASA Astrophysics Data System (ADS)

    Rauthe-Schöch, A.; Baker, A. K.; Schuck, T. J.; Brenninkmeijer, C. A. M.; Zahn, A.; Hermann, M.; Stratmann, G.; Ziereis, H.; van Velthoven, P. F. J.; Lelieveld, J.

    2015-03-01

    The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10-12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region, which so far has mostly been observed from satellites, using the broad suite of trace gases and aerosols measured by CARIBIC. Elevated levels of a range of atmospheric pollutants were recorded e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles and several volatile organic compounds. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with regular latitudinal patterns of trace gases during the entire monsoon period. Trajectory calculations indicate that these air masses originated mainly from South Asia and Mainland Southeast Asia. Using the CARIBIC trace gas and aerosol measurements in combination with the Lagrangian particle dispersion model FLEXPART we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were consistently younger (less than 7 days) and the air masses mostly in an ozone forming chemical regime. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to

  13. Process for removal of ammonia and acid gases from contaminated waters

    DOEpatents

    King, C. Judson; MacKenzie, Patricia D.

    1985-01-01

    Contaminating basic gases, i.e., ammonia, and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with steam, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

  14. Process for removal of ammonia and acid gases from contaminated waters

    DOEpatents

    King, C.J.; Mackenzie, P.D.

    1982-09-03

    Contaminating basic gases, i.e., ammonia and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with stream, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

  15. A Novel Miniaturised Infrared Imaging Spectrometer for the Measurement of Atmospheric Trace Gases

    NASA Astrophysics Data System (ADS)

    Mortimer, A. H.

    2012-04-01

    A novel, ultra-compact Static Imaging Fourier Transform Spectrometer, SIFTS, with no moving parts has been developed for the remote and in-situ detection of atmospheric gases. This technique has previously been demonstrated in the visible spectral region (400 to 1100nm) using a CCD detector. This paper the author presents the results of the infrared version of the SIFTS instrument, which uses an uncooled microbolometer detector array to measure infrared spectra (7 to 14μm) with a resolution of up 4 cm-1 and temporal resolution of 30Hz. The technique is based on a static optical configuration whereby light is split into two paths and made to recombine along a focal plane producing an interference pattern. The spectral information is returned using a detector array to digitally capture the interferogram which can then be processed into a spectrum by the application of a Fourier transform. The novel optical design has reduced the optics required to only 3 optical components and the detector array, to generate and measure the interferogram. The experimental performance of the SIFTS instrument has verified the theoretical models, which has shown that the spectral resolution is for the infrared instrument is 4cm-1. The Connes advantage, inherent to the Michelson spectrometer Fourier Transform Spectrometer (FTS), whereby the spectral wavelength accuracy is referenced to a stabilised laser has also been demonstrated in the SIFTS instrument. This has been implemented through the use of an expanded internal laser diode with Distributed Bragg Reflector (DFB) which acts as the calibration source used to maintain the wavelength stability of the SIFTS instrument. As there are no moving components, the instrument is compact, light and insensitive to mechanical vibration, additionally the speed of measurement is determined by the frame rate of the detector array. Thus, this instrument has a temporal advantage over common Michelson FTIR instruments. For example, this technique has

  16. Initial Composition, Transformations, and Transport of Particles and Trace Gases From Mexican Biomass Burning

    NASA Astrophysics Data System (ADS)

    Burling, I. R.; Yokelson, R. J.; Christian, T. J.; Akagi, S.; Urbanski, S.; Wiedinmyer, C.; Crounse, J. D.; Decarlo, P.; Clarke, A. D.

    2008-12-01

    As part of the MILAGRO project we investigated the amount, transport, and chemical composition of emissions from biomass burning (BB) in Mexico. Up to 48 trace gas and particle species were measured. BB near Mexico City (MC) and in the Yucatan was sampled from the NCAR C-130 in March 2006. During the same month, a Twin Otter aircraft deployed by the University of Montana was used to sample fires in the above areas and also forest, grass, and agricultural fires throughout much of the rest of Mexico. BB adjacent to MC accounted for about 30% of the CO and half or more of the fine particle mass in the MC-area outflow. The Yucatan measurements now provide the most comprehensive data available on the emissions from BB in tropical dry forests: the ecosystem that accounts for the most biomass burned globally. Rapid changes in ozone and many other trace gas species were observed in one BB plume. The Δ PM2.5/Δ CO ratio increased by a factor of ~ 2.6 in < 2 hours after emission as measured by both light scattering and an aerosol mass spectrometer. This is the best field evidence to date of significant secondary aerosol formation in BB plumes. During April-May 2007, ground-based, portable FTIR and particle measuring systems were deployed throughout central Mexico to characterize the emissions from garbage burning, cooking fires, brick-making kilns, and other ubiquitous, but poorly characterized sources. The first detailed chemical speciation of garbage burning emissions included the observation of extremely high HCl levels (Δ HCl/Δ CO 3.5-18%). Thus, garbage burning could be an important source of atmospheric chlorine in some regions. In addition, the HCl results suggest that large amounts of other chlorinated compounds may be emitted. Further measurements are needed, especially for highly toxic chlorinated organic compounds. Cooking fires are the second largest global source of BB emissions. The measurements of trace gas and particle emissions from cooking fires included

  17. The production of trace gases by photochemistry and lightning in the early atmosphere

    NASA Technical Reports Server (NTRS)

    Levine, J. S.; Tennille, G. M.; Towe, K. M.; Khanna, R. K.

    1986-01-01

    Recent atmospheric calculation suggest that the prebiological atmosphere was most probably composed of nitrogen, carbon dioxide, and water vapor, resulting from volatile outgassing, as opposed to the older view of a strongly reducing early atmosphere composed of methane, ammonia, and hydrogen. Photochemical calculations indicate that methane would have been readily destroyed via reaction with the hydroxyl radical produced from water vapor and that ammonia would have been readily lost via photolysis and rainout. The rapid loss of methane and ammonia, coupled with the absence of a significant source of these gases, suggest that atmospheric methane and ammonia were very short lived, if they were present at all. An early atmosphere of N2, CO2, and H2O is stable and leads to the chemical production of a number of atmospheric species of biological significance, including oxygen, ozone, carbon monoxide, formaldehyde, and hydrogen cyanide. Using a photochemical model of the early atmosphere, the chemical productionof these species over a wide range of atmospheric parameters were investigated. These calculations indicate that early atmospheric levels of O3 were significantly below the levels needed to provide UV shielding. The fate of volcanically emitted sulfur species, e.g., sulfur dioxide and hydrogen sulfide, was investigated in the early atmosphere to assess their UV shielding properties. The photochemical calculations show that these species were of insufficient levels, due in part to their short photochemical lifetimes, to provide UV shielding.

  18. Acid precipitation--effects on trace elements and human health.

    PubMed

    Gerhardsson, L; Oskarsson, A; Skerfving, S

    1994-08-22

    Environmental pollution by acid precipitation increases the solubilization and mobilization of toxic metals. Through the food chain, this may alter the intake of toxic and essential elements in man. Potential adverse health effects could follow after increased human exposure. For the general population, the exposure pattern and health effects caused by aluminium, cadmium, lead and mercury are of particular concern. Although there are several indications that the exposure to toxic elements (e.g. aluminium, cadmium, lead and methylmercury), as well as the intake of essential elements (e.g. selenium), may be affected by acid precipitation, there is presently no firm evidence of adverse health effects in man. However, the present data clearly indicate that the safety margins are small. Thus, the ongoing acidification in many areas must be stopped before such effects become evident. The effects on trace element status and human health by acid precipitation were discussed at the ISTERH (International Society for Trace Element Research in Humans) Conference in Stockholm, May, 1992. The main findings are briefly summarized here.

  19. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified...

  20. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified...

  1. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified...

  2. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified...

  3. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified...

  4. Flux measurements of energy and trace gases in urban Houston, Texas

    NASA Astrophysics Data System (ADS)

    Boedeker, I.; Schade, G. W.; Adams, S.; Park, C.

    2008-12-01

    We describe the setup and some first year results of a new flux measurements tower in an urban area. An existing radio communications tower 4 km north of downtown Houston was equipped with micrometeorological instrumentation and trace gas sampling lines in spring 2007. Wind speed, temperature and relative humidity are recorded at five levels between 12 and 60 m above ground; 3-D wind speed measurements, solar and net radiances, and trace gas sampling are established from the 60 m level. A closed path IRGA is used for CO2 and water vapor fluxes, and independent instrumentation for criteria pollutant and VOC fluxes. Two CSI data loggers and software control the measurements, and EdiRe software is used to analyze turbulence data and compute fluxes. A project description is provided at http://atmo.tamu.edu/yellowcabtower. Surface properties as calculated from the gradient measurements show the site to be surprisingly uniform, with displacement heights between 5 and 9 m and roughness lengths between 0.4 and 0.7 m, despite urban heterogeneity. The latter is investigated through visible/near IR orthoimagery and LIDAR data, which are incorporated into a local GIS. Net radiation was also only marginally affected by surface heterogeneity. At this urban location it is balanced by roughly equal amounts of sensible heat, latent heat, and storage fluxes. Latent heat flux, however, is smaller outside the growing season, with an equivalent increase in winter storage fluxes, as expected. Significant differences are also observed with direction during summer, showing decreased Bowen ratios and lower CO2 emissions from sectors with a larger urban tree canopy cover in the footprint. The largely mature, dominantly oak urban canopy cover alleviates approximately 100 W m- 2 during typical summer days. On the other hand, anthropogenic CO2 emissions dominate over photosynthetic uptake all year round. Measured carbon fluxes peak during morning rush-hour traffic, especially when increasing

  5. Global satellite analysis of the relation between aerosols and short-lived trace gases

    NASA Astrophysics Data System (ADS)

    Veefkind, J. P.; Boersma, K. F.; Wang, J.; Kurosu, T. P.; Krotkov, N.; Chance, K.; Levelt, P. F.

    2011-02-01

    The spatial and temporal correlations between concurrent satellite observations of aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and tropospheric columns of nitrogen dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO) from the Ozone Monitoring Instrument (OMI) are used to infer information on the global composition of aerosol particles. When averaging the satellite data over large regions and longer time periods, we find significant correlation between MODIS AOT and OMI trace gas columns for various regions in the world. This shows that these enhanced aerosol and trace gas concentrations originate from common sources, such as fossil fuel combustion, biomass burning, and organic compounds released from the biosphere. This leads us to propose that satellite-inferred AOT to NO2 ratios for regions with comparable photochemical regimes can be used as indicators for the relative regional pollution control of combustion processes. Indeed, satellites observe low AOT to NO2 ratios over the eastern United States and western Europe, and high AOT to NO2 ratios over comparably industrialized regions in eastern Europe and China. Emission databases and OMI SO2 observations over these regions suggest a much stronger sulfur contribution to aerosol formation than over the well-regulated areas of the eastern United States and western Europe. Furthermore, satellite observations show AOT to NO2 ratios are a factor 100 higher over biomass burning regions than over industrialized areas, reflecting the unregulated burning practices with strong primary particle emissions in the tropics compared to the heavily controlled combustion processes in the industrialized Northern Hemisphere. Simulations with a global chemistry transport model (GEOS-Chem) capture most of these variations, although on regional scales significant differences are found. Wintertime aerosol concentrations show strongest correlations with NO2 throughout most of the

  6. Laser photoacoustic analysis of trace gases emitted during electro-knife surgery on human tissue

    NASA Astrophysics Data System (ADS)

    Sigrist, Markus W.; Naegele, Markus; Lauchenauer, Daniel; Hollmann, Ralph; Kammer, Erich

    2002-06-01

    We present a fully automated mobile laser spectrometer with photoacoustic (PA) detection for trace gas analysis. A novel PA cell design permits extracavity measurements with detection limits in the sub-ppb concentration range. The setup also allows measurements with low-power sources such as quantum cascade lasers (QCL). The multicomponent capability as an important feature of the spectrometer is realized by the implementation of two sealed-off CO2 lasers with 12CO2 and 13CO2 fillings covering the spectral range between 868 cm-1 and 1088 cm-1 with 132 laser lines. The performance is demonstrated with measurements on air samples with a priori unknown composition. In particular we report on the analysis of samples taken during surgery on human breast tissue with a high-frequency (HF) electro-knife in a hospital. Besides advantages of less bleeding and lower risk of infection, the drawback of this technique is the generated fume, which in general contains dozens of species at low concentrations, some of them presumably harmful to the patient and the medical team. Our analysis of an unfiltered fume sample revealed a total of 15 species. Most of their concentrations were below the allowed workplace concentrations (if at all available). 2-Furan-carboxaldehyde (C5H4O2), however, exceeded this value of 2 ppm considerably.

  7. Carbon Dioxide Information Analysis Center and World Data Center for Atmospheric Trace Gases Fiscal Year 2001 Annual Report

    SciTech Connect

    Cushman, R.M.

    2002-10-15

    The Carbon Dioxide Information Analysis Center (CDIAC), which includes the World Data Center (WDC) for Atmospheric Trace Gases, is the primary global change data and information analysis center of the U.S. Department of Energy (DOE). More than just an archive of data sets and publications, CDIAC has, since its inception in 1982, enhanced the value of its holdings through intensive quality assurance, documentation, and integration. Whereas many traditional data centers are discipline-based (for example, meteorology or oceanography), CDIAC's scope includes potentially anything and everything that would be of value to users concerned with the greenhouse effect and global climate change, including concentrations of carbon dioxide (CO{sub 2}) and other radiatively active gases in the atmosphere; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; emissions of CO{sub 2} and other trace gases to the atmosphere; long-term climate trends; the effects of elevated CO{sub 2} on vegetation; and the vulnerability of coastal areas to rising sea levels. CDIAC is located within the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. CDIAC is co-located with ESD researchers investigating global-change topics, such as the global carbon cycle and the effects of carbon dioxide on climate and vegetation. CDIAC staff are also connected with current ORNL research on related topics, such as renewable energy and supercomputing technologies. CDIAC is supported by the Environmental Sciences Division (Jerry Elwood, Director) of DOE's Office of Biological and Environmental Research. CDIAC represents DOE in the multi-agency Global Change Data and Information System (GCDIS). Wanda Ferrell is DOE's Program Manager with overall responsibility for CDIAC. Roger Dahlman is responsible for CDIAC's AmeriFlux tasks, and Anna Palmisano for CDIAC's Ocean Data tasks. CDIAC is made up of three groups: Data

  8. Carbon Dioxide Information Analysis Center and World Data Center for Atmospheric Trace Gases Fiscal Year 1999 Annual Report

    SciTech Connect

    Cushman, R.M.

    2000-03-31

    The Carbon Dioxide Information Analysis Center (CDIAC), which includes the World Data Center (WDC) for Atmospheric Trace Gases, is the primary global-change data and information analysis center of the Department of Energy (DOE). More than just an archive of data sets and publications, CDIAC has--since its inception in 1982--enhanced the value of its holdings through intensive quality assurance, documentation, and integration. Whereas many traditional data centers are discipline-based (for example, meteorology or oceanography), CDIAC's scope includes potentially anything and everything that would be of value to users concerned with the greenhouse effect and global climate change, including concentrations of carbon dioxide (CO{sub 2}) and other radiatively active gases in the atmosphere; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; emissions of CO{sub 2} and other trace gases to the atmosphere; long-term climate trends; the effects of elevated CO{sub 2} on vegetation; and the vulnerability of coastal areas to rising sea level. CDIAC is located within the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. CDIAC is co-located with ESD researchers investigating global-change topics, such as the global carbon cycle and the effects of carbon dioxide on vegetation. CDIAC staff are also connected with current ORNL research on related topics, such as renewable energy and supercomputing technologies. CDIAC is supported by the Environmental Sciences Division (Jerry Elwood, Acting Director) of DOE's Office of Biological and Environmental Research. CDIAC's FY 1999 budget was 2.2M dollars. CDIAC represents the DOE in the multi-agency Global Change Data and Information System. Bobbi Parra, and Wanda Ferrell on an interim basis, is DOE's Program Manager with responsibility for CDIAC. CDIAC comprises three groups, Global Change Data, Computer Systems, and Information

  9. High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)

    NASA Astrophysics Data System (ADS)

    Hulley, Glynn C.; Duren, Riley M.; Hopkins, Francesca M.; Hook, Simon J.; Vance, Nick; Guillevic, Pierre; Johnson, William R.; Eng, Bjorn T.; Mihaly, Jonathan M.; Jovanovic, Veljko M.; Chazanoff, Seth L.; Staniszewski, Zak K.; Kuai, Le; Worden, John; Frankenberg, Christian; Rivera, Gerardo; Aubrey, Andrew D.; Miller, Charles E.; Malakar, Nabin K.; Sánchez Tomás, Juan M.; Holmes, Kendall T.

    2016-06-01

    Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1-2 km), and high spatial resolution (˜ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

  10. Plasma-chemical waste treatment of acid gases

    SciTech Connect

    Harkness, J.B.L.; Doctor, R.D.; Daniels, E.J.

    1993-09-01

    The research to date has shown that a H{sub 2}S waste-treatment process based on plasma-chemical dissociation technology is compatible with refinery and high-carbon-oxide acid-gas streams. The minor amounts of impurities produced in the plasma-chemical reactor should be treatable by an internal catalytic reduction step. Furthermore, the plasma-chemical technology appears to be more efficient and more economical than the current technology. The principal key to achieving high conversions with relatively low energies of dissociation is the concept of the high-velocity, cyclonic-flow pattern in the plasma reaction zone coupled with the recycling of unconverted hydrogen sulfide. Future work will include testing the effects of components that might be carried over to the plasma reactor by ``upset`` conditions in the amine purification system of a plant and testing the plasma-chemical process on other industrial wastes streams that contain potentially valuable chemical reagents. The strategy for the commercialization of this technology is to form a Cooperative Research and Development Agreement with the Institute of Hydrogen Energy and Plasma Technology of the Russian Scientific Center/Kurchatov Institute and with an American start-up company to develop an ``American`` version of the process and to build a commercial-scale demonstration unit in the United States. The timetable proposed would involve building a ``field test`` facility which would test the plasma-chemical reactor and sulfur recovery unit operations on an industrial hydrogen sulfide waste s at a scale large enough to obtain the energy and material balance data required for a final analysis of the commercial potential of this technology. The field test would then be followed by construction of a commercial demonstration unit in two to three years. The commercial demonstration unit would be a fully integrated plant consisting of one commercial-scale module.

  11. Woody encroachment by nitrogen-fixing species: impacts on nitrogen biogeochemistry expressed through nitrogen trace gases

    NASA Astrophysics Data System (ADS)

    Sparks, J. P.; West, J. B.; Boutton, T. W.

    2011-12-01

    Woody plant encroachment is a globally important vegetation change that continues to transform former grasslands or savannas into woodlands. This dramatic and geographically widespread phenomenon appears to be driven primarily by human land use changes, including reduced fire frequency and heavy livestock grazing. Observed effects of increased woody plant abundance in grasslands generally include alterations of above- and belowground productivity, changes in the chemistry of litter inputs, modifications to rooting depths and distributions, altered biogeochemical and hydrologic processes, and changes in microclimate and energy balance. These changes to fundamental ecosystem characteristics have strong, but relatively poorly understood, potential to modify biogeochemical processes that can themselves influence regional and global climate through biogeochemistry-climate feedbacks. In addition, in South Texas woody encroachment has occurred across a complex landscape differing in soil type and water retention. This work tests the hypothesis that woody encroachment, in addition to increasing total nitrogen stocks in the system, has increased nitrogen losses due to increased rates of nitrogen soil gas efflux. Under dry soil conditions and in contrast to this hypothesis, reactive nitrogen soil efflux (NO + NOy + NH3) was 21.53 ± 3.4 ng N m-2 s-1 in intact grasslands compared to 6.23 ± 1.6 ng N m-2 s-1 in woodlands on the same soil type. The non-reactive nitrogen gas, nitrous oxide, was similar in magnitude between the grassland and encroached sites (~ 7 ng N m-2 s-1). Under moist soil conditions, the magnitude of flux increased and order of magnitude, but did not change the relative ranking. Measurements of soil respiration rate and microbial biomass suggest higher microbial activity in the encroached environment and potentially higher rates of immobilization by plants and microbes. Landscape position had a large overall effect on soil nitrogen trace gas efflux with

  12. Numerical modelling of the transport of trace gases including methane in the subsurface of Mars

    NASA Astrophysics Data System (ADS)

    Stevens, Adam H.; Patel, Manish R.; Lewis, Stephen R.

    2015-04-01

    We model the transport of gas through the martian subsurface in order to quantify the timescales of release of a trace gas with a source at depth using a Fickian model of diffusion through a putative martian regolith column. The model is then applied to the case of methane to determine if diffusive transport of gas can explain previous observations of methane in the martian atmosphere. We investigate which parameters in the model have the greatest effect on transport timescales and show that the calculated diffusivity is very sensitive to the pressure profile of the subsurface, but relatively insensitive to the temperature profile, though diffusive transport may be affected by other temperature dependent properties of the subsurface such as the local vapour pressure. Uncertainties in the structure and physical conditions of the martian subsurface also introduce uncertainties in the timescales calculated. It was found that methane may take several hundred thousand Mars-years to diffuse from a source at depth. Purely diffusive transport cannot explain transient release that varies on timescales of less than one martian year from sources such as serpentinization or methanogenic organisms at depths of more than 2 km. However, diffusion of gas released by the destabilisation of methane clathrate hydrates close to the surface, for example caused by transient mass wasting events or erosion, could produce a rapidly varying flux of methane into the atmosphere of more than 10-3 kg m-2 s-1 over a duration of less than half a martian year, consistent with observations of martian methane variability. Seismic events, magmatic intrusions or impacts could also potentially produce similar patterns of release, but are far more complex to simulate.

  13. Linking aerosol size and optical properties to trace gases emitted from biomass burning in real-time

    NASA Astrophysics Data System (ADS)

    McMeeking, G. R.; Carrico, C. M.; Stockwell, C.; Yokelson, R. J.; Veres, P. R.; DeMott, P. J.; Kreidenweis, S. M.

    2014-12-01

    Biomass burning aerosols have large impacts on regional and global climate that are partly determined by their optical properties. The optical properties of aerosol depend on their size and composition, which in turn are related to fire combustion processes. Here we investigate relationships between a large suite of trace gases and aerosol size and optical properties to better understand processes governing the optical properties of fresh biomass burning aerosol emissions. We examined over 100 individual burns of biomass fuels during the Fire Laboratory at Missoula Experiment 4 (FLAME 4). Emissions were measured directly from an exhaust stack designed to capture all emissions from relatively small-scale fires burned at the base of a large burn chamber. Trace gas species were measured using a combination of an open-path Fourier transform infrared spectrometer (OP-FTIR) and proton-transfer mass spectrometer (PTR-MS). Aerosol optical properties at 870 nm were measured using a photoacoustic extinctiometer (PAX) and particle size distributions were measured using a Fast Mobility Particle Sizer (FMPS) and Aerodynamic Particle Sizer. The rapid response of the instruments allowed for comparisons of the emissions and particle properties over the duration of the fire. For example, we observed correlations between aerosol absorption, particle size, and gas-phase species associated with different types of combustion such as flaming and smoldering. We also report fire-integrated emissions for aerosol absorption and scattering coefficients and compare these to other fire-integrated properties. Many of our burn experiments examined a number of fuels that had not before been characterized in laboratory conditions, including a number of peat fuels, African savanna grasses and crop residuals.

  14. Interactions of atmospheric particulate and trace gases with clouds at Cheeka Peak, WA

    NASA Astrophysics Data System (ADS)

    Samberg, Tristine Marie

    1997-12-01

    Measurements of various aerosol, trace gas, and cloud water constituents were made during two intensive observation periods at the Cheeka Peak Observatory (CPO) on the Washington state coast. These measurements were a part of the second and third Cloud and Aerosol Chemistry Experiments (CAChE 2 and CAChE 3) conducted from April 19 to May 18, 1994 and August 30 to September 23, 1994, respectively. Gas phase hydrogen peroxide was measured continuously during these two time periods. Cloud water samples were analyzed for major ion constituents and aqueous hydrogen peroxide. The cloud water samples collected during CAChE 2 represented bulk collection, whereas the cloud water samples collected during CAChE 3 were segregated into two size fractions, with mean droplet diameter of approximately 12 μm and 13 μm. Major ion concentrations (e.g., Na+, NH4+, H+, NO3/sp-, SO4/sp=, etc.) were higher than previously observed at Cheeka Peak, but comparable to other West coast locations. Despite the small difference in collected droplet size, size dependence was observed for several species. Seasalt ions and NO3/sp- were more concentrated in the larger drops, whereas peroxide was more concentrated in the smaller drops. Size dependence was not observed for MSA, non seasalt sulfate (nss-SO4/sp=) and NH4+, and was only weakly observed for H+. Cloud-free gas phase H2O2 and organic peroxide average concentrations were on the order of a few hundred pptv and did not vary much by wind sector; slightly higher concentrations were observed from the continental sector. In general, these concentrations were lower than those measured at east coast sites. Average cloudwater H2O2 concentrations for both CAChE experiments were approximately 35 μM and indicated conditions at Cheeka Peak were never oxidant-limited.. Evidence for sulfate production via H2O2 oxidation was observed but was not conclusive. Finally, a preliminary comparison was made between predictions of a size-resolved cloud chemical

  15. Investigating atmospheric transport processes of trace gases with ICON-ART on different scales

    NASA Astrophysics Data System (ADS)

    Schröter, Jennifer; Ruhnke, Roland; Rieger, Daniel; Vogel, Heike; Vogel, Bernhard

    2016-04-01

    We have extended the global ICON [1] (ICOsahedral Nonhydrostatic) modelling framework by introducing ICON-ART [2]. ICON is jointly developed by the German Weather Service (DWD) and Max-Planck-Institute for Meteorology (MPI-M), and is used for numerical weather prediction as well as for future climate predictions. ICON-ART is developed at the KIT with the goal to simulate interactions between trace substances and the state of the atmosphere. For the dynamics (transport and diffusion) of gaseous tracers, the original ICON tracer framework is used. A process splitting approach separates the physical processes. In this study, we present results of the ICON-ART extension, including the full gas-phase chemistry module. This module uses the kpp formalism [3] to generate chemistry modules and the photolysis module is based on Cloud-J7.3 [4]. Photolysis rates are calculated online based on the meteorological state of the atmosphere, as well as on the actual ozone profile and cloud optical parameters. Two simulations are performed with ICON-ART. The first one with physics parameterisations for the numerical weather prediction (NWP) and the second one with that for climate simulation in order to investigate the dynamical influence on the distribution of long-lived as well as of short-lived species by comparing both simulations. The results are evaluated with other model results and with observation. In addition to that, we use aircraft campaign data to validate the results on the regional scale for short term simulations by using the NWP physics. [1] Zängl, G., Reinert, D., Ripodas, P., and Baldauf, M.: The ICON (ICOsahedral Non-hydrostatic) modelling framework of DWD and MPI-M: Description of the non-hydrostatic dynamicalcore, Q. J. Roy. Meteor. Soc,141, 563-579, doi:10.1002/qj.2378, 2015 [2] Rieger, D., Bangert, M., Bischoff-Gauss, I., Förstner, J., Lundgren, K., Reinert, D., Schröter, J., Vogel, H., Zängl, G., Ruhnke, R., and Vogel, B.: ICON-ART 1.0 - a new online

  16. Spatiotemporal Patterns of Urban Trace Gases and Pollutants Observed with a Light Rail Vehicle Platform in Salt Lake City, UT

    NASA Astrophysics Data System (ADS)

    Mitchell, L.; Crosman, E.; Fasoli, B.; Leclair-Marzolf, L.; Jacques, A.; Horel, J.; Lin, J. C.; Bowling, D. R.; Ehleringer, J. R.

    2015-12-01

    Urban environments are characterized by both spatial complexity and temporal variability, each of which present challenges for measurement strategies aimed at constraining estimates of greenhouse gas emissions and air quality. To address these challenges we initiated a project in December 2014 to measure trace species (CO2, CH4, O3, and Particulate Matter) by way of a Utah Transit Authority (UTA) light rail vehicle whose route traverses the Salt Lake Valley in Utah on an hourly basis, retracing the same route through commercial, residential, suburban, and rural typologies. Light rail vehicles present advantages as a measurement platform, including the absence of in-situ fossil fuel emissions, repeated transects across a urban region that provides both spatial and temporal information, and relatively low operating costs. We present initial results from the first year of operations including the spatiotemporal patterns of greenhouse gases and pollutants across Salt Lake City, UT with an emphasis on criteria pollutants, identification of sources, and future applications of this measurement platform.

  17. Effects of Higher Hydrocarbon Chemistry On Tropospheric Trace Gases and The Yield of Co From Hydrocarbon Oxidation

    NASA Astrophysics Data System (ADS)

    von Kuhlmann, R.; Lawrence, M. G.; Crutzen, P. J.

    Non-methane hydrocarbons are known to be emitted in large amounts from anthro- pogenic and biogenic sources. The impact of these emissions on key tropospheric trace gases, such as O3, CO, NOx, and OH are investigated using the Model of Atmospheric Transport and Chemistry, Max-Planck-Institute for Chemistry version (MATCH-MPIC). This study expands upon previous work by the use of detailed bud- gets in order to elucidate further the underlying mechanisms of the changes. Isoprene alone, which is emitted in large amounts by tropical ecosystems, is found to contribute more than half of the overall effect of hydrocarbons in the tropics. The model's budget- ing capabilities are further used to determine the yield of CO from methane, isoprene and other hydrocarbons. While 92% of methane is converted to CO, the yields for iso- prene and the sum of other hydrocarbons is lower, both being 39% on a per carbon ba- sis. A detailed analysis of the loss-pathways are also presented and show that a major loss occurs through deposition of soluble intermediates of isoprene oxidation, partic- ularly hydroxy-hydroperoxides, which are explicitly treated in the chemical scheme. The results are compared and discussed with previous estimates from the literature, which shows that the uncertainty in CO production is likely significant compared to the uncertainties in the direct emissions.

  18. Emissions of Trace Gases and Particles from Savanna Fires in Southern Africa

    NASA Technical Reports Server (NTRS)

    Sinha, Parikhit; Hobbs, Peter V.; Yokelson, Robert J.; Bertschi, Isaac T.; Blake, Donald R.; Simpson, Isobel J.; Gao, Song; Kirchstetter, Thomas W.; Novakov, Tica

    2003-01-01

    Airborne measurements made on initial smoke from 10 savanna fires in southern Africa provide quantitative data on emissions of 50 gaseous and particulate species, including carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, methane, ammonia, dimethyl sulfide, nonmethane organic compounds, halocarbons, gaseous organic acids, aerosol ionic components, carbonaceous aerosols, and condensation nuclei (CN). Measurements of several of the gaseous species by gas chromatography and Fourier transform infrared spectroscopy are compared. Emission ratios and emission factors are given for eight species that have not been reported previously for biomass burning of savanna in southern Africa (namely, dimethyl sulfide, methyl nitrate, five hydrocarbons, and particles with diameters from 0.1 to 3 microns). The emission factor that we measured for ammonia is lower by a factor of 4, and the emission factors for formaldehyde, hydrogen cyanide, and CN are greater by factors of about 3, 20, and 3 - 15, respectively, than previously reported values. The new emission factors are used to estimate annual emissions of these species from savanna fires in Africa and worldwide.

  19. A fiber optic sensor with a metal organic framework as a sensing material for trace levels of water in industrial gases.

    PubMed

    Ohira, Shin-Ichi; Miki, Yusuke; Matsuzaki, Toru; Nakamura, Nao; Sato, Yu-ki; Hirose, Yasuo; Toda, Kei

    2015-07-30

    Industrial gases such as nitrogen, oxygen, argon, and helium are easily contaminated with water during production, transfer and use, because there is a high volume fraction of water in the atmosphere (approximately 1.2% estimated with the average annual atmospheric temperature and relative humidity). Even trace water (<1 parts per million by volume (ppmv) of H2O, dew point < -76 °C) in the industrial gases can cause quality problems in the process such as production of semiconductors. Therefore, it is important to monitor and to control trace water levels in industrial gases at each supplying step, and especially during their use. In the present study, a fiber optic gas sensor was investigated for monitoring trace water levels in industrial gases. The sensor consists of a film containing a metal organic framework (MOF). MOFs are made of metals coordinated to organic ligands, and have mesoscale pores that adsorb gas molecules. When the MOF, copper benzene-1,3,5-tricarboxylate (Cu-BTC), was used as a sensing material, we investigated the color of Cu-BTC with water adsorption changed both in depth and tone. Cu-BTC crystals appeared deep blue in dry gases, and then changed to light blue in wet gases. An optical gas sensor with the Cu-BTC film was developed using a light emitting diode as the light source and a photodiode as the light intensity detector. The sensor showed a reversible response to trace water, did not require heating to remove the adsorbed water molecules. The sample gas flow rate did not affect the sensitivity. The obtained limit of detection was 40 parts per billion by volume (ppbv). The response time for sample gas containing 2.5 ppmvH2O was 23 s. The standard deviation obtained for daily analysis of 1.0 ppmvH2O standard gas over 20 days was 9%. Furthermore, the type of industrial gas did not affect the sensitivity. These properties mean the sensor will be applicable to trace water detection in various industrial gases. PMID:26320652

  20. Field measurements of trace gases and aerosols emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Niño

    NASA Astrophysics Data System (ADS)

    Stockwell, Chelsea E.; Jayarathne, Thilina; Cochrane, Mark A.; Ryan, Kevin C.; Putra, Erianto I.; Saharjo, Bambang H.; Nurhayati, Ati D.; Albar, Israr; Blake, Donald R.; Simpson, Isobel J.; Stone, Elizabeth A.; Yokelson, Robert J.

    2016-09-01

    Peat fires in Southeast Asia have become a major annual source of trace gases and particles to the regional-global atmosphere. The assessment of their influence on atmospheric chemistry, climate, air quality, and health has been uncertain partly due to a lack of field measurements of the smoke characteristics. During the strong 2015 El Niño event we deployed a mobile smoke sampling team in the Indonesian province of Central Kalimantan on the island of Borneo and made the first, or rare, field measurements of trace gases, aerosol optical properties, and aerosol mass emissions for authentic peat fires burning at various depths in different peat types. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared spectroscopy, whole air sampling, photoacoustic extinctiometers (405 and 870 nm), and a small subset of the data from analyses of particulate filters. The trace gas measurements provide emission factors (EFs; grams of a compound per kilogram biomass burned) for up to ˜ 90 gases, including CO2, CO, CH4, non-methane hydrocarbons up to C10, 15 oxygenated organic compounds, NH3, HCN, NOx, OCS, HCl, etc. The modified combustion efficiency (MCE) of the smoke sources ranged from 0.693 to 0.835 with an average of 0.772 ± 0.053 (n = 35), indicating essentially pure smoldering combustion, and the emissions were not initially strongly lofted. The major trace gas emissions by mass (EF as g kg-1) were carbon dioxide (1564 ± 77), carbon monoxide (291 ± 49), methane (9.51 ± 4.74), hydrogen cyanide (5.75 ± 1.60), acetic acid (3.89 ± 1.65), ammonia (2.86 ± 1.00), methanol (2.14 ± 1.22), ethane (1.52 ± 0.66), dihydrogen (1.22 ± 1.01), propylene (1.07 ± 0.53), propane (0.989 ± 0.644), ethylene (0.961 ± 0.528), benzene (0.954 ± 0.394), formaldehyde (0.867 ± 0.479), hydroxyacetone (0.860 ± 0.433), furan (0.772 ± 0.035), acetaldehyde (0.697 ± 0.460), and acetone (0.691 ± 0.356). These field data support significant revision

  1. Differential Radiometers Using Fabry-Perot Interferometric Technique for Remote Sensing Determination of Various Atmospheric Trace Gases

    NASA Technical Reports Server (NTRS)

    Georgieva, E. M.; Heaps, W. S.; Wilson, E. L.

    2007-01-01

    New type of remote sensing instrument based upon the Fabry-Perot inte rferometric technique has been developed at NASA's Goddard Space Flight Center. Fabry-Perot interferometry (FPI) is a well known, powerful spectroscopic technique and one of its many applications is to be use d to measure greenhouse gases and also some harmful species in the at mosphere. With this technique, absorption of particular species is me asured and related to its concentration. A solid Fabry-Perot etalon is used as a frequency filter to restrict the measurement to particular absorption bands of the gas of interest. With adjusting the thicknes s of the etalon that separation (in frequency) of the transmitted fri nges can be made equal to the almost constant separation of the gas a bsorption lines. By adjusting the temperature of the etalon, which changes the index of refi-action of its material, the transmission fring es can be brought into nearly exact correspondence with absorption li nes of the particular species. With this alignment between absorption lines and fringes, changes in the amount of a species in the atmosph ere strongly affect the amount of light transmitted by the etalon and can be related to gas concentration. The instrument that we have dev eloped detects the absorption of various atmospheric trace gases in d irect or reflected sunlight. Our instrument employing Fabry-Perot interferometer makes use of two features to achieve high sensitivity. The first is high spectral resolution enabling one to match the width of an atmospheric absorption feature by the instrumental band pass. The second is high optical throughput enabled by using multiple spectral lines simultaneously. For any species that one wishes to measure, thi s first feature is available while the use of multiple spectral features can be employed only for species with suitable spectra and freedom from interfering species in the same wavelength region. We have deve loped an instrument for use as ground based

  2. A new UK Greenhouse Gas measurement network providing ultra high-frequency measurements of key radiatively active trace gases taken from a network of tall towers

    NASA Astrophysics Data System (ADS)

    Grant, A.; O'Doherty, S.; Manning, A. J.; Simmonds, P. G.; Derwent, R. G.; Moncrieff, J. B.; Sturges, W. T.

    2012-04-01

    Monitoring of atmospheric concentrations of gases is important in assessing the impact of international policies related to the atmospheric environment. The effects of control measures on greenhouse gases introduced under the Montreal and Kyoto Protocols are now being observed. Continued monitoring is required to assess the overall success of the Protocols. For over 15 years the UK Government have funded high-frequency measurements of greenhouse gases and ozone depleting gases at Mace Head, a global background measurement station on the west coast of Ireland. These continuous, high-frequency, high-precision measurements are used to estimate regional (country-scale) emissions of greenhouse gases across the UK using an inversion methodology (NAME-Inversion) that links the Met Office atmospheric dispersion model (Numerical Atmospheric dispersion Modelling Environment - NAME) with the Mace Head observations. This unique inversion method acts to independently verify bottom up emission estimates of radiatively active and ozone-depleting trace gases. In 2011 the UK government (DECC) funded the establishment and integration of three new tall tower measurements stations in the UK, to provide enhanced resolution emission maps and decrease uncertainty of regional emission estimates produced using the NAME-Inversion. One station included in this new UK network was already established in Scotland and was used in collaboration with Edinburgh University. The two other new stations are in England and were set-up early in 2012, they contain brand new instrumentation for measurements of greenhouse gases. All three additional stations provide ultra high-frequency (1 sec) data of CO2 and CH4 using the Picarro© Cavity Ring Down Spectrometer and high frequency (20 min) measurements of N2O and SF6 from custom built sample modules with GC-ECD. We will present the new tall tower UK measurement network in detail. Using high-frequency measurements at new operational sites, including Mace

  3. Soluble species in the Arctic summer troposphere - acidic gases, aerosols, and precipitation

    SciTech Connect

    Talbot, R.W.; Vijgen, A.S.; Harriss, R.C. Old Dominion Univ., Norfolk, VA )

    1992-10-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions. 61 refs.

  4. Soluble species in the Arctic summer troposphere - Acidic gases, aerosols, and precipitation

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-01-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions.

  5. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... limits for municipal waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are... from that affected facility any gases that contain hydrogen chloride in excess of 29 parts per million by volume or 5 percent of the potential hydrogen chloride emission concentration...

  6. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  7. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limits for municipal waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are... from that affected facility any gases that contain hydrogen chloride in excess of 29 parts per million by volume or 5 percent of the potential hydrogen chloride emission concentration...

  8. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  9. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limits for municipal waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are... from that affected facility any gases that contain hydrogen chloride in excess of 29 parts per million by volume or 5 percent of the potential hydrogen chloride emission concentration...

  10. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  11. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limits for municipal waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are... from that affected facility any gases that contain hydrogen chloride in excess of 29 parts per million by volume or 5 percent of the potential hydrogen chloride emission concentration...

  12. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  13. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limits for municipal waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are... from that affected facility any gases that contain hydrogen chloride in excess of 29 parts per million by volume or 5 percent of the potential hydrogen chloride emission concentration...

  14. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... waste combustor acid gases, expressed as sulfur dioxide and hydrogen chloride, are specified in... include emission limits for hydrogen chloride at least as protective as the emission limits for hydrogen... hydrogen chloride contained in the gases discharged to the atmosphere from a designated facility is...

  15. Shallow borehole array for measuring fluxes of reduced trace gases in Greenland as an analogue for volatile emission on Mars

    NASA Astrophysics Data System (ADS)

    Pratt, L. M.

    2011-12-01

    -packer-optic-capillary system as a technology demonstration of semi-autonomous drilling for planetary exploration. Carbon and hydrogen isotopic compositions for methane and ethane will be determined in the field using Integrated Cavity Output Spectroscopy and Cavity Ring Down Spectroscopy. Continuous permafrost is present at the study site down to 300 m depth with temperatures dropping to -3 degrees C at a depth of about 4 meters, providing a relatively shallow and pristine setting for an instrumented study of reduced trace gases in soil, fractured bedrock, and groundwater constituting the active layer.

  16. Raman Scattering Sensor for On-Line Monitoring of Amines and Acid Gases

    SciTech Connect

    Uibel, Rory; Smith, Lee

    2010-05-20

    Sulfur and CO2 removal from hydrocarbon streams and power plant effluents are a major problem. The sulfur is normally in the form of H2S. These two acid gases are scrubbed using aqueous amine solutions that are difficult to control with conventional technology. Process Instruments Inc. developed Raman scattering technology for on-line, real-time monitoring of amine streams to improve their efficiency in scrubbing H2S and CO2 from hydrocarbon streams and power plant effluents. Improved control of amine and acid gas concentrations will allow refineries, natural gas processes and power plants to more efficiently scrub Sulfur and CO2, saving energy, time and financial resources.

  17. Measurements of reactive trace gases and variable O3 formation rates in some South Carolina biomass burning plumes

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Yokelson, R. J.; Burling, I. R.; Meinardi, S.; Simpson, I.; Blake, D. R.; McMeeking, G. R.; Sullivan, A.; Lee, T.; Kreidenweis, S.; Urbanski, S.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Weise, D. R.

    2013-02-01

    In October-November 2011 we measured trace gas emission factors from seven prescribed fires in South Carolina (SC), US, using two Fourier transform infrared spectrometer (FTIR) systems and whole air sampling (WAS) into canisters followed by gas-chromatographic analysis. A total of 97 trace gas species were quantified from both airborne and ground-based sampling platforms, making this one of the most detailed field studies of fire emissions to date. The measurements include the first emission factors for a suite of monoterpenes produced by heating vegetative fuels during field fires. The first quantitative FTIR observations of limonene in smoke are reported along with an expanded suite of monoterpenes measured by WAS including α-pinene, β-pinene, limonene, camphene, 4-carene, and myrcene. The known chemistry of the monoterpenes and their measured abundance of 0.4-27.9% of non-methane organic compounds (NMOCs) and ~ 21% of organic aerosol (mass basis) suggests that they impacted secondary formation of ozone (O3), aerosols, and small organic trace gases such as methanol and formaldehyde in the sampled plumes in the first few hours after emission. The variability in the initial terpene emissions in the SC fire plumes was high and, in general, the speciation of the initially emitted gas-phase NMOCs was 13-195% different from that observed in a similar study in nominally similar pine forests in North Carolina ~ 20 months earlier. It is likely that differences in stand structure and environmental conditions contributed to the high variability observed within and between these studies. Similar factors may explain much of the variability in initial emissions in the literature. The ΔHCN/ΔCO emission ratio, however, was found to be fairly consistent with previous airborne fire measurements in other coniferous-dominated ecosystems, with the mean for these studies being 0.90 ± 0.06%, further confirming the value of HCN as a biomass burning tracer. The SC results also

  18. Measurements of reactive trace gases and variable O3 formation rates in some South Carolina biomass burning plumes

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Yokelson, R. J.; Burling, I. R.; Meinardi, S.; Simpson, I.; Blake, D. R.; McMeeking, G. R.; Sullivan, A.; Lee, T.; Kreidenweis, S.; Urbanski, S.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Weise, D. R.

    2012-09-01

    In October-November 2011 we measured trace gas emission factors from seven prescribed fires in South Carolina (SC), US, using two Fourier transform infrared spectrometer (FTIR) systems and whole air sampling (WAS) into canisters followed by gas-chromatographic analysis. A total of 97 trace gas species were quantified from both airborne and ground-based sampling platforms, making this one of the most detailed field studies of fire emissions to date. The measurements include the first emission factors for a suite of monoterpenes produced by heating vegetative fuels during field fires. The first quantitative FTIR observations of limonene in smoke are reported along with an expanded suite of monoterpenes measured by WAS including α-pinene, β-pinene, limonene, camphene, 4-carene, and myrcene. The known chemistry of the monoterpenes and their measured abundance of 0.4-27.9% of non-methane organic compounds (NMOCs) and ~21% of organic aerosol (mass basis) suggests that they impacted secondary formation of ozone (O3), aerosols, and small organic trace gases such as methanol and formaldehyde in the sampled plumes in first few hours after emission. The variability in the initial terpene emissions in the SC fire plumes was high and, in general, the speciation of the initially emitted gas-phase NMOCs was 13-195% different from that observed in a similar study in nominally similar pine forests in North Carolina ~20 months earlier. It is likely that differences in stand structure and environmental conditions contributed to the high variability observed within and between these studies. Similar factors may explain much of the variability in initial emissions in the literature. The ΔHCN/ΔCO emission ratio, however, was found to be fairly consistent with previous airborne fire measurements in other coniferous-dominated ecosystems, with the mean for these studies being 0.90 ± 0.06%, further confirming the value of HCN as a biomass burning tracer. The SC results also support an

  19. Use of Satellite and Surface Observations of Trace Gases to Evaluate the Impact of Fire Emissions on Air Quality in Euro-Mediterranean Area

    NASA Astrophysics Data System (ADS)

    Messina, P.; Turquety, S.; Anav, A.; Stromatas, S.; Menut, L.; Coheur, P.-F.; R'honi, Y.; Bessagnet, B.; Clerbaux, C.

    2012-11-01

    Wildfires are one of the main source of trace gases and aerosols. However, their impact remains poorly quantified due to large uncertainties on the emissions, but also on transport processes and chemical evolution of the pollution plumes. Satellite data, due to their high spatial coverage, can be a powerful tool for monitoring pollution plumes transport, although the information remains vertically integrated, implying limited vertical resolution. Here we present an evaluation of the effects, provided by fire emissions, on atmospheric trace gases composition. Therefore, simulations by the regional chemistry-transport model CHIMERE are performed using an high resolution fire emissions scenario. Comparison between satellite observations and model output is then conducted, focusing on the strong biomass burning episodes that occurred in late summer 2007 in Greece.

  20. Separation and identification of carboxylic acids in MALT samples from the headspace gases in Hanford tank 103C

    SciTech Connect

    Clauss, S.A.; Lucke, R.B.

    1993-08-01

    Samples of headspace gases from Westinghouse Hanford Company (WHC) waste storage tank 103C were analyzed by gas chromatography/mass spectrometry by Pacific Northwest Laboratory staff. The samples were obtained using a cryo-trap sampler designed by WHC and known as the Mobile Analytical Laboratory Trap (MALT). The samples, which were obtained in September 1989, were available in large amounts (200 mi). The specific targets for this analysis were n-butyric, i-butyric, n-valeric, and i-valeric organic acids. Of the acids targeted, only n-butyric was found, and only trace amounts of it were detected with a detection limit below 1 ppM in the extract. The levels found were so low as to cause difficulty in quantitation. All concentrations reported here are for the methanol extract solutions and not the concentrations in the headspace of tank 103C. To calculate concentrations in the headspace, the MALT sampling volume and the methanol rinse volume must be obtained from the MALT personnel at WHC.

  1. Measurement of gas/water uptake coefficients for trace gases active in the marine environment. [Annual report

    SciTech Connect

    Davidovits, P.; Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E.

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean`s surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry`s law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  2. Ratios among atmospheric trace gases together with winds imply exploitable information for bird navigation: a model elucidating experimental results

    NASA Astrophysics Data System (ADS)

    Wallraff, H. G.

    2013-11-01

    A model of avian goal-oriented navigation is described that is based on two empirical findings building a bridge from ornithology to atmospheric chemistry. (1) To orient their courses homeward from distant unfamiliar areas, homing pigeons require long-term exposure to undisturbed winds at the home site and olfactory access to the environmental air at home and abroad. (2) Above Germany, ratios among some atmospheric trace gases vary along differently oriented spatial gradients as well as depending on wind direction. The model emulates finding (1) by utilising the analysed air samples on which finding (2) is based. Starting with an available set of 46 omnipresent compounds, virtual pigeons determine the profile of relative weights among them at each of 96 sites regularly distributed around a central home site within a radius of 200 km and compare this profile with corresponding profiles determined at home under varying wind conditions. Referring to particular similarities and dissimilarities depending on home-wind direction, they try to estimate, at each site, the compass direction they should fly in order to approach home. To make the model work, an iterative algorithm imitates evolution by modifying sensitivity to the individual compounds stepwise at random. In the course of thousands of trial-and-error steps it gradually improves homeward orientation by selecting smaller sets of most useful and optimally weighted substances from whose proportional configurations at home and abroad it finally derives navigational performances similar to those accomplished by real pigeons. It is concluded that the dynamic chemical atmosphere most likely contains sufficient spatial information for home-finding over hundreds of kilometres of unfamiliar terrain. The underlying chemo-atmospheric processes remain to be clarified.

  3. Ratios among atmospheric trace gases together with winds imply exploitable information for bird navigation: a model elucidating experimental results

    NASA Astrophysics Data System (ADS)

    Wallraff, H. G.

    2013-07-01

    A model of avian goal-oriented navigation is described that is based on two empirical findings: (1) To orient their courses homeward from distant unfamiliar areas, homing pigeons require long-term exposure to undisturbed winds at the home site and olfactory access to the environmental air at home and abroad. (2) Above Germany, ratios among some atmospheric trace gases vary along differently oriented spatial gradients and in dependence on wind direction. The model emulates finding (1) by utilising the analysed air samples on which finding (2) is based. Starting with an available set of 46 omnipresent compounds, virtual pigeons determine the profile of relative weights among them at each of 96 sites regularly distributed around a central home site within a radius of 200 km and compare this profile with corresponding profiles determined at home under varying wind conditions. Referring to particular similarities and dissimilarities depending on home-wind direction, they try to estimate, at each site, the compass direction they should fly in order to approach home. To make the model working, an iterative algorithm imitates evolution by modifying sensitivity to the individual compounds stepwise at random. In the course of thousands of trial-and-error steps it gradually improves homeward orientation by selecting smaller sets of most useful and optimally weighted substances from whose proportional configurations at home and abroad it finally derives navigational performances similar to those accomplished by real pigeons. It is concluded that the dynamic chemical atmosphere most likely contains sufficient spatial information for home-finding over hundreds of kilometres of unfamiliar terrain. The underlying chemo-atmospheric processes remain to be clarified.

  4. Fire emissions in Euro-Mediterranean area: evaluation of the impact on trace gases composition using satellite and surface observations

    NASA Astrophysics Data System (ADS)

    Messina, P.; Turquety, S.; Stromatas, S.; Menut, L.; Anav, A.; Coheur, P.-F.; R'honi, Y.; Bessagnet, B.; Clerbaux, C.

    2012-04-01

    Wildfires are one of the main sources of trace gases and aerosols. However, their impact remains poorly quantified due to large uncertainties especially on the emissions, as well as on the transport processes and chemical evolution of the pollution plumes. In the framework of APIFLAME project a new high resolution fire emission inventory is developed. Simulations performed with the regional chemistry transport model CHIMERE, are carried out in order to assess the effect of the emissions scenarios on air quality in Europe and Mediterranean basin. For a comprehensive evaluation of the processes involved with fire emissions and a validation of simulations, the modeled species are compared to satellite observations and ground measurements. The latter data have good accuracy with high temporal resolution, but they are collected at specific locations and, in general for our case study, are far away from the location where wildfires occur. On the other hand, the satellite data, due to their high spatial coverage, can be a useful tool for monitoring pollution plumes transport, but their vertical resolution is often limited to a total column amount. In this study, the modeled concentrations are compared to the ground measurements (CO, O3 and NO2 concentrations) that come from AirBase database, and to CO partial columns and CO, NH3 and C2H4 total columns from the IASI instrument, to NO2 and CH2O total columns from GOME2 (both on MetOp-A satellite) and to NO2 total columns from OMI (on Aura). In the presented work we focus on strong biomass burning episodes that occurred in summer 2007. Particular attention is given to the evolution of the plume characteristics. The same fire inventory setup is used for both reanalysis and near-real time analysis. The first evaluation of the air quality forecasting system including fires will be presented.

  5. Biological production of acetic acid from waste gases with Clostridium ljungdahlii

    DOEpatents

    Gaddy, J.L.

    1998-09-15

    A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 5 figs.

  6. Biological production of acetic acid from waste gases with Clostridium ljungdahlii

    DOEpatents

    Gaddy, James L.

    1998-01-01

    A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

  7. Utilization of hydrogen sulfide from acidic gases produced in treatment with amines

    SciTech Connect

    Lunin, A.F.; Hussein, A.H.; Burdeinaya, T.N.

    1994-07-01

    Treatment with amines is the basic method for removing hydrogen sulfide from gases. When such treatment is used, there is a problem in utilizing the acidic regeneration gases, which consist of carbon dioxide, hydrogen sulfide, and C{sub 1}-C{sub 4} hydrocarbons. If the concentration of hydrogen sulfide in these gases is below 20%, it is best removed by direct oxidation by oxygen to form sulfur or sulfur dioxide, over solid or liquid catalysts. Here we are reporting on an investigation of the activity and selectivity of commercial oxide catalysts in this reaction. Commercial catalysts were used in the direct oxidation of gas containing hydrogen sulfide (2-4% hydrogen sulfide, 1-4% C{sub 1}-C{sub 4} hydrocarbons, remainder carbon dioxide) in a laboratory flow unit with a fixed bed of catalyst. The compositions of the feed and the reaction products were determined by gas-liquid chromatography. The oxidation of hydrogen sulfide may proceed with the formation of either sulfur dioxide or sulfur. Catalyst activity was rated on the basis of the total conversion of hydrogen sulfide, the percentage conversions to elemental sulfur and sulfur dioxide, and the selectivity for the formation of elemental sulfur. The catalyst activities were investigated at temperatures of 170-270{degrees}C, space velocity of feed 300 h{sup -1}, hydrogen sulfide concentration 2-4%, and O{sub 2}: H{sub 2}S ratio 1.

  8. Modeling Soil Climate Controls on the Exchange of Trace Gases Between the Terrestrial Biosphere and the Atmosphere

    NASA Astrophysics Data System (ADS)

    Frolking, Stephen Edward

    Soil temperature and moisture profiles (soil climate) have a strong influence on the rate of trace gas exchange between the terrestrial biosphere and the atmosphere through the controls exerted on microbial processes and the physical exchange of gases. Principal controls of biological denitrification in mineral soils are the availability of carbon and nitrogen substrates and the soil anaerobic status. A process-oriented model of decomposition and denitrification in soils (DNDC) was modified to have a more detailed portrayal of these controls. In particular, a diffusive soil gas phase was added, along with a method for determining anaerobic and aerobic fractional volume within a soil profile. The model generally overestimated N2O fluxes when compared to field data from a sandy soil in Costa Rica, but captured the timing and shape of the brief flux episodes. Several modeling shortcomings are discussed, including the nature of the carbon substrates and the nature and dynamics of soil anaerobic fractional volume. Methane flux from wetland soils is generally correlated with soil temperature and depth to water table. A model of peat soil climate was developed and applied to a small, poor fen in southern New Hampshire. Temperature profiles and ice depth are in good agreement with field data, but depth to water table is more problematic. Field-based flux correlations to soil temperature, depth to water table, and weighted recent precipitation were developed. When used with the wetland soil climate model, much of the seasonal and shorter period flux variability was captured. The model was then driven by local weather data for 1926-1986; flux variability was dependent on both summer season temperatures and summer precipitation patterns. It is estimated that a five-year field study would capture most of the inter -annual variability. Sensitivity of northern peatland methane flux to climate variability was studied by combining data on flux rates, inundation areas, and summer

  9. Airborne measurements and emission estimates of greenhouse gases and other trace constituents from the 2013 California Yosemite Rim wildfire

    NASA Astrophysics Data System (ADS)

    Yates, E. L.; Iraci, L. T.; Singh, H. B.; Tanaka, T.; Roby, M. C.; Hamill, P.; Clements, C. B.; Lareau, N.; Contezac, J.; Blake, D. R.; Simpson, I. J.; Wisthaler, A.; Mikoviny, T.; Diskin, G. S.; Beyersdorf, A. J.; Choi, Y.; Ryerson, T. B.; Jimenez, J. L.; Campuzano-Jost, P.; Loewenstein, M.; Gore, W.

    2016-02-01

    This paper presents airborne measurements of multiple atmospheric trace constituents including greenhouse gases (such as CO2, CH4, O3) and biomass burning tracers (such as CO, CH3CN) downwind of an exceptionally large wildfire. In summer 2013, the Rim wildfire, ignited just west of the Yosemite National Park, California, and burned over 250,000 acres of the forest during the 2-month period (17 August to 24 October) before it was extinguished. The Rim wildfire plume was intercepted by flights carried out by the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) on 29 August and the NASA DC-8, as part of SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys), on 26 and 27 August during its intense, primary burning period. AJAX revisited the wildfire on 10 September when the conditions were increasingly smoldering, with slower growth. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of AJAX (e. g. CO). Data analyses are presented in terms of emission ratios (ER), emission factors (EF) and combustion efficiency and are compared with previous wildfire studies. ERs were 8.0 ppb CH4 (ppm CO2)-1 on 26 August, 6.5 ppb CH4 (ppm CO2)-1 on 29 August and 18.3 ppb CH4 (ppm CO2)-1 on 10 September 2013. The increase in CH4 ER from 6.5 to 8.0 ppb CH4 (ppm CO2)-1 during the primary burning period to 18.3 ppb CH4 (ppm CO2)-1 during the fire's slower growth period likely indicates enhanced CH4 emissions from increased smoldering combustion relative to flaming combustion. Given the magnitude of the Rim wildfire, the impacts it had on regional air quality and the limited sampling of wildfire emissions in the western United States to date, this study provides a valuable dataset to support forestry and regional air quality management, including observations of ERs of a wide number of species from the Rim wildfire.

  10. Autonomous Long-Path DOAS Measurements of Tropospheric Trace Gases at Neumayer Station III, Antarctica: First Results

    NASA Astrophysics Data System (ADS)

    Nasse, Jan-Marcus; Frieß, Udo; Pöhler, Denis; Weller, Rolf; Platt, Ulrich

    2016-04-01

    Reactive Halogen Species (RHS, like IO, BrO, ClO, etc.) have an important impact on atmospheric chemistry. In Polar Regions, the role of halogen radical chemistry has been subject of intensive research for more than two decades. Among the most prominent effects of RHS on the Polar atmosphere are the change of the oxidative capacity of the troposphere including wide-spread and frequently virtually complete destruction of tropospheric ozone, in particular during springtime, as well as the oxidation and subsequent deposition of gaseous elemental mercury. The number of field observations and the understanding of the underlying processes varies greatly between bromine, iodine and chlorine compounds. While elevated BrO concentrations resulting from autocatalytic processes (the so-called bromine explosion mechanism) are frequently observed, the abundance and influence of iodine is still subject to discussions and available observations give no consistent picture. With only a few direct observations of chlorine compounds, such as ClO and OClO, the role of tropospheric chlorine chemistry remains poorly understood to date, despite strong evidence for its relevance. The lack of observations of chlorine radicals is mainly due to the challenging detection, particularly in the case of ClO. Scattered sunlight DOAS measurements, which are available from a number of Polar locations, are not sensitive for ClO, due to insufficient radiation intensity in the UV spectral region (<308nm) where this molecule is absorbing. Here we present the overall design and first results of a novel Long Path DOAS (Differential Optical Absorption Spectroscopy) instrument with an active light source suitable for the detection of ClO. It has been set up at the German Research Station Neumayer III in coastal Antarctica during the summer season 2015/16 and is planned to operate autonomously for at least one year. The instrument is able to detect - in addition to ClO - many trace gases absorbing in the UV

  11. Airborne Measurements and Emission Estimates of Greenhouse Gases and Other Trace Constituents From the 2013 California Yosemite Rim Wildfire

    NASA Technical Reports Server (NTRS)

    Yates, E. L.; Iraci, L. T.; Singh, H. B.; Tanaka, T.; Roby, M. C.; Hamill, P.; Clements, C. B.; Lareau, N.; Contezac, J.; Blake, D. R.; Simpson, I. J.; Wisthaler, A.; Mikoviny, T.; Diskin, G. S.; Beyersdorf, A. J.; Choi, Y.; Ryerson, T. B.; Jimenez, J. L.; Campuzano-Jost, P.; Loewenstein, M.; Gore, W.

    2015-01-01

    This paper presents airborne measurements of multiple atmospheric trace constituents including greenhouse gases (such as CO2, CH4, O3) and biomass burning tracers (such as CO, CH3CN) downwind of an exceptionally large wildfire. In summer 2013, the Rim wildfire, ignited just west of the Yosemite National Park, California, and burned over 250,000 acres of the forest during the 2-month period (17 August to 24 October) before it was extinguished. The Rim wildfire plume was intercepted by flights carried out by the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) on 29 August and the NASA DC-8, as part of SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys), on 26 and 27 August during its intense, primary burning period. AJAX revisited the wildfire on 10 September when the conditions were increasingly smoldering, with slower growth. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of AJAX (e. g. CO). Data analyses are presented in terms of emission ratios (ER), emission factors (EF) and combustion efficiency and are compared with previous wildfire studies. ERs were 8.0 ppb CH4/(ppm CO2) on 26 August, 6.5 ppb CH4 (ppm CO2)1 on 29 August and 18.3 ppb CH4 (ppm CO2)1 on 10 September 2013. The increase in CH4 ER from 6.5 to 8.0 ppb CH4/(ppm CO2) during the primary burning period to 18.3 ppb CH4/(ppm CO2) during the fire's slower growth period likely indicates enhanced CH4 emissions from increased smoldering combustion relative to flaming combustion. Given the magnitude of the Rim wildfire, the impacts it had on regional air quality and the limited sampling of wildfire emissions in the western United States to date, this study provides a valuable dataset to support forestry and regional air quality management, including observations of ERs of a wide number of species from the Rim wildfire.

  12. Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania, 41° S

    NASA Astrophysics Data System (ADS)

    Lawson, S. J.; Keywood, M. D.; Galbally, I. E.; Gras, J. L.; Cainey, J. M.; Cope, M. E.; Krummel, P. B.; Fraser, P. J.; Steele, L. P.; Bentley, S. T.; Meyer, C. P.; Ristovski, Z.; Goldstein, A. H.

    2015-07-01

    with a large CO enhancement, an increase of the NMOC / CO emission ratio (ER) by a factor of 2-4 and a halving of the BC / CO ratio. Rainfall on Robbins Island was observed by radar during this period which likely resulted in a lower fire combustion efficiency, and higher emission of compounds associated with smouldering. This highlights the importance of relatively minor meterological events on BB emissions. Emission factors (EF) were derived for a range of trace gases, some never before reported for Australian conditions, (including hydrogen, phenol and toluene) using a calculated ER to CO and a published CO EF. The EF derived for most species are comparable to other temperate Australian studies but lower than Northern Hemisphere temperate studies. This work demonstrates the substantial impact that BB plumes have on the composition of marine air, and the significant changes that can occur as the plume is diluted and interacts with other emission sources. We also provide new trace gas and particle EF for temperate southern Australia.

  13. Dating of young groundwater using four anthropogenic trace gases (SF6, SF5CF3, CFC-12 and Halon-1301): methodology and first results.

    PubMed

    Bartyzel, Jakub; Rozanski, Kazimierz

    2016-01-01

    A dedicated, GC-based analytical system is presented which allows detection of four anthropogenic trace gases (SF6, SF5CF3, CFC-12 and Halon-1301) in a single water sample, with detection limits and measurement uncertainties sufficiently low to employ them as quantitative indicators of groundwater age. The gases dissolved in water are extracted in the field using the method based on a dynamic head-space concept. In the laboratory, the investigated gases are cryogenically enriched, separated and measured using an electron capture detector. Reproducibility of the analyses is in the order of 2-5 %. The investigated tracers were measured in several production wells located in the recharge area of an intensively exploited aquifer in southern Poland. While the piston-flow ages of groundwater in the investigated wells revealed internal consistency, they appeared to be generally smaller than the ages derived from time series of tritium content in those wells, interpreted by lumped-parameter models. This difference stems mainly from significantly longer travel times of tritium through the unsaturated zone, when compared to the gaseous tracers being used. The results of this study highlight the benefits of using multiple tracing in quantifying timescales of groundwater flow in shallow aquifer systems. PMID:26863003

  14. Aerodynamics control of a cave with a high environmental stability by trace gases monitoring (Castañar de Íbor, Spain)

    NASA Astrophysics Data System (ADS)

    Sanchez-Moral, S.; Fernandez-Cortes, A.; Cuezva, S.; Canaveras, J. C.; Abella, R.

    2009-04-01

    High-accuracy monitoring of a "low energy" cave (Castañar de Íbor, Spain) determined the temporal evolution of the aerodynamics processes and ventilation rate by tracking CO2 and 222Rn levels over a twelve-month period. Beside the general patterns of cave microclimate throughout an annual cycle, some particular microclimatic processes are described with regard to the gases exchange between cave and outer atmosphere. Special attention is paid to the key role of the isolation effect of host rock and soil on the confined cave atmosphere, determined by the water saturation state of this double-membrane. In this sense we focus on the complicate microclimatic functional relationship between the meteorological and cave microclimate conditions and the diffusion and flow of trace gases from the fractures and the pore system of soil and host rock to cave atmosphere. Finally, inferences are drawn about the physical mechanisms controlling the short-term fluctuations of trace gases levels on cave air, such as barometric fluxes and forced ventilation due to uncontrolled opening of cave entrance. The application of the knowledge regarding mass and energy fluxes involved in the subterranean environments is also discussed.

  15. Dating of young groundwater using four anthropogenic trace gases (SF6, SF5CF3, CFC-12 and Halon-1301): methodology and first results.

    PubMed

    Bartyzel, Jakub; Rozanski, Kazimierz

    2016-01-01

    A dedicated, GC-based analytical system is presented which allows detection of four anthropogenic trace gases (SF6, SF5CF3, CFC-12 and Halon-1301) in a single water sample, with detection limits and measurement uncertainties sufficiently low to employ them as quantitative indicators of groundwater age. The gases dissolved in water are extracted in the field using the method based on a dynamic head-space concept. In the laboratory, the investigated gases are cryogenically enriched, separated and measured using an electron capture detector. Reproducibility of the analyses is in the order of 2-5 %. The investigated tracers were measured in several production wells located in the recharge area of an intensively exploited aquifer in southern Poland. While the piston-flow ages of groundwater in the investigated wells revealed internal consistency, they appeared to be generally smaller than the ages derived from time series of tritium content in those wells, interpreted by lumped-parameter models. This difference stems mainly from significantly longer travel times of tritium through the unsaturated zone, when compared to the gaseous tracers being used. The results of this study highlight the benefits of using multiple tracing in quantifying timescales of groundwater flow in shallow aquifer systems.

  16. Light emitting diode cavity enhanced differential optical absorption spectroscopy (LED-CE-DOAS): a novel technique for monitoring atmospheric trace gases

    NASA Astrophysics Data System (ADS)

    Thalman, Ryan M.; Volkamer, Rainer M.

    2009-08-01

    The combination of Cavity Enhanced Absorption Spectroscopy (CEAS) with broad-band light sources (e.g. Light- Emitting Diodes, LEDs) lends itself to the application of cavity enhanced DOAS (CE-DOAS) to perform sensitive and selective point measurements of multiple trace gases with a single instrument. In contrast to other broad-band CEAS techniques, CE-DOAS relies only on the measurement of relative intensity changes, i.e., does not require knowledge of the light intensity in the absence of trace gases and aerosols (I0). We have built a prototype LED-CE-DOAS instrument in the blue spectral range (420-490nm) to measure nitrogen dioxide (NO2), glyoxal (CHOCHO), iodine monoxide (IO), water (H2O) and oxygen dimers (O4). Aerosol extinction is retrieved at two wavelengths by means of observing water and O4 and measuring pressure, temperature and relative humidity independently. The instrument components are presented, and the approach to measure aerosol extinction is demonstrated by means of a set of experiments where laboratory generated monodisperse aerosols are added to the cavity. The aerosol extinction cross section agrees well with Mie calculations, demonstrating that our setup enables measurements of the above gases in open cavity mode.

  17. Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases.

    PubMed

    Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

    2013-01-01

    The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay. PMID:23907148

  18. Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases

    NASA Astrophysics Data System (ADS)

    Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

    2013-08-01

    The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay.

  19. Regeneration of absorbents used for purifying effluent gases from acidic components

    SciTech Connect

    Gladkii, A.V.; Ivanina, I.N.

    1982-09-20

    The purpose of this report was to study the equilibrium conditions for the interaction between sodium sulfate and the calcium salts of various carboxylic acids. The experimental data presented can be recommended for engineering calculations for the regeneration of spent absorbent containing sodium sulfate or a mixture of sodium sulfate, sulfite, phosphate, and fluoride in various combinations, since, as previously shown, the equilibrium constants for the reaction between sodium sulfite, phosphate, or fluoride and calcium hydroxide or calcium carboxylate are large and thus an absorbent with these components is almost completely regenerated. The present data can be used for planning and putting into effect the purification of gases from acidic components in various branches of industry.

  20. Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases.

    PubMed

    Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

    2013-01-01

    The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay.

  1. Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases

    PubMed Central

    Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

    2013-01-01

    The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay. PMID:23907148

  2. Measuring fluxes of trace gases and energy between ecosystems and the atmosphere - the state and future of the eddy covariance method.

    PubMed

    Baldocchi, Dennis

    2014-12-01

    The application of the eddy covariance flux method to measure fluxes of trace gas and energy between ecosystems and the atmosphere has exploded over the past 25 years. This opinion paper provides a perspective on the contributions and future opportunities of the eddy covariance method. First, the paper discusses the pros and cons of this method relative to other methods used to measure the exchange of trace gases between ecosystems and the atmosphere. Second, it discusses how the use of eddy covariance method has grown and evolved. Today, more than 400 flux measurement sites are operating world-wide and the duration of the time series exceed a decade at dozens of sites. Networks of tower sites now enable scientists to ask scientific questions related to climatic and ecological gradients, disturbance, changes in land use, and management. The paper ends with discussions on where the field of flux measurement is heading. Topics discussed include role of open access data sharing and data mining, in this new era of big data, and opportunities new sensors that measure a variety of trace gases, like volatile organic carbon compounds, methane and nitrous oxide, and aerosols, may yield.

  3. Soluble species in the Arctic summer troposphere: Acidic gases, aerosols, and precipitation

    NASA Astrophysics Data System (ADS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-10-01

    We report here the distribution of selected acidic gases and aerosol species in the North American Arctic and sub-Arctic summer troposphere. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases and acidic sulfate aerosols dominating the particulate phase. Our data show that the acidic gas and aerosol composition is uniform on a large spatial scale. There appears to be a surface source of NH4+ over the Arctic Ocean pack ice which may reflect release of NH3 from decay of dead marine organisms on the ice surface near ice leads, release from rotting sea ice, or an upward flux from surface ocean waters in open ice leads. This NH3 appears to partially neutralize aerosol acidity in the boundary layer. Over sub-Arctic tundra in southwestern Alaska inputs of marine biogenic sulfur from the nearby Bering Sea appear to be an important source of boundary layer aerosol SO42-. While there were only minor effects on aerosol chemistry over the tundra from sea salt, the rainwater chemistry showed influence from marine aerosols which were apparently incorporated into air masses during frontal passages moving inland from the Bering Sea. The rainwater acidity over the tundra (pH 4.69) is typical of remote regions. The principal acidity components are H2SO4 and carboxylic acids, especially HCOOH. The carboxylic acids appear to have a strong continental biogenic source, but hydrocarbons of marine origin and emissions from forest fires may also be important. The wet deposition fluxes of NO3--N and SO42--S over sub-Arctic tundra during July-August 1988 were 2.1 and 2.4 mmol m-2 yr-1. Wet deposition of NO3- was nearly 3 times higher than the average NOy deposition flux, which is believed to represent primarily dry deposition of HNO3 (Bakwin et al., this issue). Our measurements indicate that the mid-troposphere in the Arctic is generally contaminated with low levels of anthropogenic pollutants even in summer when direct atmospheric coupling

  4. Fundamental Understanding of the Interaction of Acid Gases with CeO2 : From Surface Science to Practical Catalysis

    DOE PAGES

    Tumuluri, Uma; Rother, Gernot; Wu, Zili

    2016-03-21

    Acid gases including CO2, SO2, and NOx are ubiquitous in large-scale energy applications including heterogeneous catalysis. The adverse environmental and health effects of these acid gases have resulted in high interest in the research and development of technologies to remove or convert these acid gases. The main challenge for the development of these technologies is to develop catalysts that are highly efficient, stable, and cost-effective, and many catalysts have been reported in this regard. CeO2 and CeO2-based catalysts have gained prominence in the removal and conversion of CO2, SO2, and NOx because of their structural robustness and redox and acid–basemore » properties. In this article, we provide a brief overview of the application of CeO2 and CeO2-based catalysts for the removal of CO2, SO2, and NOx gases with an emphasis on the fundamental understanding of the interactions of these acid gases with CeO2. The studies summarized in this review range from surface science using single crystals and thin films with precise crystallographic planes to practical catalysis applications of nanocrystalline and polycrystalline CeO2 materials with defects and dopants. After an introduction to the properties of CeO2 surfaces, their catalytic properties for conversions of different acid gases are reviewed and discussed. Lastly, we find that the surface atomic structure, oxygen vacancies, and surface acid–base properties of CeO2 play vital roles in the surface chemistry and structure evolution during the interactions of acid gases with CeO2 and CeO2-based catalysts.« less

  5. Chemical Gradient and Inter-hemispheric Distribution of Selected Organic Trace Gases in the Tropical Tropopause Layer Over the Western Pacific

    NASA Astrophysics Data System (ADS)

    Navarro, M. A.; Atlas, E. L.; Schauffler, S.; Donets, V.; Lueb, R.; Hendershot, R.; Gabbard, S.; Saiz-Lopez, A.; Rodriguez, X.; Kinnison, D. E.; Lamarque, J. F.; Zhu, X.; Pope, L.

    2014-12-01

    Hydrocarbons and short-lived species play an important role in the chemistry of the upper troposphere/lower stratosphere (UT/LS) region. Their distribution, vertical structure and variability provide information about emission sources and transport. Furthermore, the characterization of short-lived organic halogens defines the reactive halogen budget and the conditions for the stratospheric chemistry that affects ozone depletion rates. The chemical composition of the air masses entering the stratosphere depends on the chemical and physical processes that occur during their transitions through the Tropical Tropopause Layer (TTL). It is well known that convective systems effectively transport short-lived trace gases to the UT. However, the overall impact of these processes on the distribution and budget of trace gases is not well known since only high altitude aircraft can reach this region of the atmosphere (>13-14 Km) During the recent field campaign of the Airborne Tropical Tropopause Experiment (ATTREX) and the Convective Transport of Active Species in the Tropics (CONTRAST), carried out in Guam during January-March 2014, the Whole Air Samplers (GWAS and AWAS) collected approximately 1200 samples to examine the tropical convection of the west pacific and its influence on the distribution of the short-lived species from the bottom of the TTL to the lower stratosphere. Measurement of a wide range of hydrocarbons, halocarbons, organic nitrates and solvents were carried out in the field using a combination of gas chromatography with mass selective, flame ionization, and electron capture detectors. In addition, model simulations of selected hydrocarbon and organic trace gases were performed with the chemistry climate model CAM-Chem to evaluate the chemical gradients and inter-hemispheric distributions. In this presentation we will show the gradients and inter-hemispheric distributions from the measurements and compare them with the model results.

  6. Horizonal and Vertical Spatial Patterns of Radon and Other Soil-gases Across the El Pilar Fault Trace at Guaraphiche, Edo. Surce (Venezuela)

    NASA Astrophysics Data System (ADS)

    LaBrecque, J. J.

    2002-05-01

    Soil-gases (radon, thoron, carbon dioxide and hydrogen) were measured at 63-cm depths along a transect perpendicular to the rupture (fault trace) from the 1997 Caricao earthquake (Mw=6.9) at Guarapiche, state of Sucre (Venezuela). The transect was about 40 meters long with ten sampling points with the spacings was smaller near the rupture. The shapes of the horizontal spatial patterns for radon (Rn-222), thoron (Rn-220) and total radon (Rn-222+Rn-220) were similar; the gas concentrations increased from both ends of the transect toward the rupture where a dip (valley) occurred. Both carbon dioxide and hydrogen gases showed anomalous values at the same sampling points. Twin peaks (anomalies) had been previously reported and suggested that they were due to blockage in the rupture. We have also determined soil-gases from 25-cm to 155-cm depths near the rupture and at the ends of the transect. The results showed that the soil-gas concentrations were not only higher in the upper levels (less than 65-cm) near the fault trace but were similar or greater than the lower levels. Thus, producing the twin peaks when soil-gas sampling was performed at the 65-cm depth. When the sampling was performed at only 45-cm depth the dip over the rupture was much less and the patterns looked more like a broad doublet peak. In conclusion, one can clearly see that not only positive soil-gas anomalies can occur over a fault trace but also negative ones too. 1) This work was partially funded by a research contract from the Venezuelan National Science Foundation (CONICIT Proyecto S1-95000448). 2) Mailing Address: Centro de Quimica, 8424 NW 56th Street, Suite 00204,Miami, Fl 33166 (USA). E-mail jjlabrec@ivic.ve FAX: +58-212-504-1214

  7. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    PubMed

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site.

  8. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    PubMed

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site. PMID:27083259

  9. Application of ion-induced nucleation mass spectrometry in the analysis of trace gases evolved from a polyimide film during the thermal curing stages

    NASA Technical Reports Server (NTRS)

    Smith, A. C.

    1982-01-01

    Trace gases evolved from a polyimide film during its thermal curing stages have been studied using ion-induced nucleation mass spectrometry. The technique involved exposing the test gas sample to a low energy beta source and recording the masses of the ion-induced molecular clusters formed in the reaction chamber. On the basis of the experimentally observed molecular cluster spectra, it has been concluded that the dominant trace component had a molecular weight of 87 atomic mass units. This component has been identified as a molecule of dimethylacetamide (DMAC) which had been used as a solvent in the preparation of the test polyimide specimen. This identification has been further confirmed by comparing the spectra of the test gas sample and the DMAC calibration sample obtained with a conventional mass spectrometer. The advantages of the ion-induced nucleation mass spectrometer versus the conventional mass spectrometer are discussed.

  10. Composition and Trends of Short-Lived Trace Gases in the UT/LS over Europe Observed by the CARIBIC Aircraft

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Brenninkmeijer, C. A.; Oram, D. E.; O'Sullivan, D. A.; Slemr, F.; Schuck, T. J.

    2009-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from aboard a commercial airliner, and has operated since 2005 from aboard a Lufthansa Airbus 340-600 . Measurements from the container include in-situ trace gas and aerosol analyses and the collection of aerosol and whole air samples for post-flight laboratory analysis. Measurements made from the sampling flasks include greenhouse gas (GHG), halocarbon and nonmethane hydrocarbon (NMHC) analysis. CARIBIC flights originate in Frankfurt, Germany with routes to India, East Asia, South America, North America and Africa, and typical aircraft cruising altitudes of 10-12km allow for the monitoring of the upper troposphere/lower stratosphere (UT/LS) along these routes. Data collected during the aircraft’s departure from and return to Frankfurt provide a 4 year time series of near-monthly measurements of the composition of the UT/LS above Europe. Here we present a discussion of the composition of short-lived trace gases in the whole air samples collected above Europe during CARIBIC flights. Over 150 air samples were collected between May 2005 and July 2009, or about 4 samples per month. Of the whole air samples collected, about 45% showed influence by stratospheric air (i.e. very low values of GHG, NMHC and halocarbons, elevated O3, high potential vorticity). The remaining samples were representative of the upper troposphere; back trajectories for these samples indicate that a little over half were collected in air masses that had been in the boundary layer within the previous 8 days. The predominant source regions for these samples were the Gulf of Mexico and continental North America. Owing to their wide range of chemical lifetimes and the varying composition of emissions, short-lived trace gases transported to the UT/LS can be useful indicators of source

  11. Nighttime chemical evolution of aerosol and trace gases in a power plant plume: Implications for secondary organic nitrate and organosulfate aerosol formation, NO3 radical chemistry, and N2O5 heterogeneous hydrolysis

    SciTech Connect

    Zaveri, R.A.; Kleinman, L.; Berkowitz, C. M.; Brechtel, F. J.; Gilles, M. K.; Hubbe, J. M.; Jayne, J. T.; Laskin, A.; Madronich, S.; Onasch, T. B.; Pekour, M. S.; Springston, S. R.; Thornton, J. A.; Tivanski, A. V.; Worsnop, D. R.

    2010-06-01

    Nighttime chemical evolution of aerosol and trace gases in a coal-fired power plant plume was monitored with the Department of Energy Grumman Gulfstream-1 aircraft during the 2002 New England Air Quality Study field campaign. Quasi-Lagrangian sampling in the plume at increasing downwind distances and processing times was guided by a constant-volume balloon that was released near the power plant at sunset. While no evidence of fly ash particles was found, concentrations of particulate organics, sulfate, and nitrate were higher in the plume than in the background air. The enhanced sulfate concentrations were attributed to direct emissions of gaseous H{sub 2}SO{sub 4}, some of which had formed new particles as evidenced by enhanced concentrations of nucleation-mode particles in the plume. The aerosol species were internally mixed and the particles were acidic, suggesting that particulate nitrate was in the form of organic nitrate. The enhanced particulate organic and nitrate masses in the plume were inferred as secondary organic aerosol, which was possibly formed from NO{sub 3} radical-initiated oxidation of isoprene and other trace organic gases in the presence of acidic sulfate particles. Microspectroscopic analysis of particle samples suggested that some sulfate was in the form of organosulfates. Microspectroscopy also revealed the presence of sp{sup 2} hybridized C = C bonds, which decreased with increasing processing time in the plume, possibly because of heterogeneous chemistry on particulate organics. Constrained plume modeling analysis of the aircraft and tetroon observations showed that heterogeneous hydrolysis of N{sub 2}O{sub 5} was negligibly slow. These results have significant implications for several issues related to the impacts of power plant emissions on air quality and climate.

  12. Field method comparison for the characterization of acid aerosols and gases

    NASA Astrophysics Data System (ADS)

    Suh, Helen H.; Allen, George A.; Aurian-Blájeni, Benedict; Koutrakis, Petros; Burton, Robert M.

    This paper presents findings from two intercomparison studies of acid aerosol measurement systems, which were conducted in Uniontown and State College, PA, during the summers of 1990 and 1991, respectively. As part of these studies, acid aerosol and gas concentrations (NH 3, HNO 3, HNO 2, SO 2, H +, NH 4+, NO 3, SO 42-) were measured using five systems: the Harvard/EPA Annular Denuder Systems (HEADS), the Personal Annular Denuder System (PADS), the Continuous Sulfate/Thermal Speciation system (CSTS), the Micro-Orifice Impactor (MOI), and the Harvard Marple Impactor (HI). Concentrations were measured over 3, 12, and 24 h periods, with resultant acid aerosol and gas measurements compared for each system. Results from these studies show excellent agreement among the particulate measurement systems. The sulfate (SO 42-), aerosol strong acidity (H +), and ammonium (NH 4+) concentrations measured by all systems were highly correlated. In addition, 3 and 12 h particulate measurements were comparable for HEADS, MO1, and PADS samplers. Although significantly different, mean relative differences between HEADS measurements and those obtained using the HI and CSTS (SO 42- only) systems were small. For the gases nitric acid (HNO 3) and sulfur dioxide (SO 2), the performance of the HEADS sampler was found to be independent of sample duration, as the 3 and 12 h HEADS measurements were comparable. The PADS sampler, however, was found to measure concentrations of both HNO 3 and SO 2 poorly. PADS measurements, of HNO 3 in particular, were significantly lower than corresponding HEADS measurements. These lower values probably resulted from their deposition on the inlet surfaces of the PADS sampler. The performance of the measurement systems for ammonia (NH 3), nitrous acid (HONO), and nitrate (NO 3-) could not be determined, since their outdoor levels generally were near or below the limit of detection (LOD).

  13. Uncertainties in the current knowledge of some atmospheric trace gases associated with U.S. agriculture: a review.

    PubMed

    Krupa, Sagar; Booker, Fitzerald; Bowersox, Van; Lehmann, Christopher; Lehmann, Chris Topher; Grantz, David

    2008-08-01

    Approximately 80 different crop species are grown in the United States in widely differing geographic areas, climatic and edaphic conditions, and management practices. Although the majority of cultivated acreage in the United States is planted with only about 10 primary crops, uncertainties associated with trace gas emissions arise from: (1) limited data availability, (2) inaccurate estimates because of large temporal and spatial variability in trace gas composition and magnitude of trace gas emissions from agricultural activities, (3) differing characteristics of pollutant emissions from highly dispersed animal feed-lots, and (4) limited understanding of the emissions of semi-volatile organic compounds (SVOCs) associated with agriculture. Although emission issues are of concern, so also is atmospheric deposition to cropping systems, including wet and dry nitrogen, minerals, and organic compounds. These can have feedback effects on trace gas emissions. Overall, the many gaps in our understanding of these aspects of agricultural systems deserve serious attention.

  14. Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques.

    PubMed

    Kim, Min Jung; Lee, Jihye; Kim, Seon Hee; Kim, Haidong; Lee, Kang-Bong; Lee, Yeonhee

    2015-10-01

    Chalcopyrite Cu(In, Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In, Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT.

  15. Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques.

    PubMed

    Kim, Min Jung; Lee, Jihye; Kim, Seon Hee; Kim, Haidong; Lee, Kang-Bong; Lee, Yeonhee

    2015-10-01

    Chalcopyrite Cu(In, Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In, Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT. PMID:26726401

  16. Measurements of Trace Gases and Particles in Fresh and Aged Smoke from a Chaparral Fire in California

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Craven, J. S.; Taylor, J. W.; McMeeking, G. R.; Yokelson, R. J.; Burling, I. R.; Alvarado, M. J.; Seinfeld, J.; Coe, H.; Urbanski, S. P.

    2010-12-01

    On November 17th 2009 we used a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, Licor CO2 analyzer, and a chemiluminescence ozone instrument to measure the initial emissions from a 100 hectare prescribed fire in chaparral fuels on the central coast of California, U.S.A. We also measured the post emission chemical changes in the isolated downwind plume for a distance corresponding to about 4.5 hours of smoke aging. The light scattering to CO2 ratio increased by a factor of ~2.7 over 4 hours: similar to observations in a biomass burning plume in Mexico where significant secondary formation of organic aerosol (OA) was confirmed by AMS. However, in the California plume, a decrease in OA was observed by AMS along with a concurrent increase in the fraction of thickly coated particles as measured by the SP2. Decreasing OA accompanied by increased scattering/coating may be explained by a combination of coagulation and evaporation processes. The latter may have been promoted in the California plume because it diluted in a “clean,” low relative humidity (11-26%) environment compared to the Mexican plume. AFTIR measured significant changes in gas phase constituents. The molar ratio of O3 to CO increased from approximately zero to 0.102 in 4.5 hours. Large growth factors for organic acids were also observed over the same aging period: acetic acid and formic acid increased by factors of 1.68 and 7.13, respectively. Inorganic species measured by the AMS also increased with plume aging. While the mass ratio of NH4+ to CO2 increased by ~2.3 x 10-4 in about 4 hours, the NH3/CO2 decreased by ~4.1 x 10-4, with ammonium accounting for ~55% of the gaseous ammonia lost (by mass). Conversion of NOx to PAN was observed coincident with formation of particle nitrate. A rapid decay in C2H4 was consistent with an in-plume average OH of ~5.40 x 106 molecules

  17. Enhanced adsorption of acidic gases (CO2, NO2 and SO2) on light metal decorated graphene oxide.

    PubMed

    Chen, Chi; Xu, Kui; Ji, Xiao; Miao, Ling; Jiang, Jianjun

    2014-06-14

    The adsorption of several acidic gases (CO2, NO2 and SO2) on light metal (Li, Al) decorated graphene oxide (GO) is theoretically studied, based on the first-principles calculations. Configuration relaxation, binding energy and charge transfer are carried out to discuss the acidic gas adsorption ability of light metal decorated GO. It is found out that Li, Al could be anchored stably by hydroxyl and epoxy groups on GO, and then a strong adsorption of CO2, NO2 and SO2 will occur above these light metals. In contrast to Ti, Li decorated GO exhibits a comparable adsorption ability of acidic gases, but a much smaller interaction with O2 about 2.85-3.98 eV lower in binding energy; and Al decorated GO displays much higher binding energy of all acidic gases with an enhancement of about 0.59-2.29 eV. The results of enhanced acidic gas adsorption ability and a reduced interference by O2 imply that Li, Al decorated GO may be useful and promising for collection and filtration of exhaust gases.

  18. An evaluation of trace element release associated with acid mine drainage

    NASA Astrophysics Data System (ADS)

    Sullivan, Patrick J.; Yelton, Jennifer L.

    1988-12-01

    The determination of trace element release from geologic materials, such as oil shale and coal overburden, is important for proper solid waste management planning. The objective of this study was to determine a correlation between trace element residency and concentration to trace element release using the following methods: (1) sequential selective dissolution for determining trace element residencies, (2) toxicity characteristic leaching procedure (TCLP), and (3) humidity cell weathering study simulating maximum trace element release. Two eastern oil shales were used, a New albany shale that contains 4.6 percent pyrite, and a Chattanooga shale that contains 1.5 percent pyrite. Each shale was analyzed for elemental concentrations by soluble, adsorbed, organic, carbonate, and sulfide phases. All leachates were analyzed to determine total trace element concentrations. The results of the selective dissolution studies show that each trace element has a unique distribution between the various phases. Thus, it is possible to predict trace element release based on trace element residency. The TCLP results show that this method is suitable for assessing soluble trace element release but does not realistically assess potential hazards. The results of the humidity cell studies do demonstrate a more reasonable method for predicting trace element release and potential water quality hazards. The humidity cell methods, however, require months to obtain the required data with a large number of analytical measurements. When the selective dissolution data are compared to the trace element concentrations in the TCLP and humidity cell leachates, it is shown that leachate concentrations are predicted by the selective dissolution data. Therefore, selective dissolution may represent a rapid method to assess trace element release associated with acid mine drainage.

  19. Continuous renal replacement therapy amino acid, trace metal and folate clearance in critically ill children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We hypothesized that continuous veno-venous hemodialysis (CVVHD) results in amino acid, trace metals, and folate losses, thereby adversely impacting nutrient balance. Critically ill children receiving CVVHD were studied prospectively for 5 days. Blood concentrations, amino acids, copper, zinc, man...

  20. Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)

    USGS Publications Warehouse

    Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.

    2014-01-01

    Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

  1. Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)

    NASA Astrophysics Data System (ADS)

    Porubsky, W. P.; Weston, N. B.; Moore, W. S.; Ruppel, C.; Joye, S. B.

    2014-04-01

    Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

  2. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study

    SciTech Connect

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-15

    Highlights: • Two scenarios of acid gases removal in WTE plants were compared in an LCA study. • A detailed inventory based on primary data has been reported for the production of the new dolomitic sorbent. • Results show that the comparison between the two scenarios does not show systematic differences. • The potential impacts are reduced only if there is an increase in the energy efficiency of the WTE plant. - Abstract: The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO{sub 2} emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in

  3. Measurements of Acidic Gases and Aerosol Species Aboard the NASA DC-8 Aircraft During the Pacific Exploratory Mission in the Tropics (PEM-Tropics A)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    We received funding to provide measurements of nitric acid (HNO3), formic acid (HCOOH), acetic acid (CH3COOH), and the chemical composition of aerosols aboard the NASA Ames DC-8 research aircraft during the PEM-Tropics A mission. These measurements were successfully completed and the final data resides in the electronic archive (ftp-gte.larc.nasa.gov) at NASA Langley Research Center. For the PEM-Tropics A mission the University of New Hampshire group was first author of four different manuscripts. Three of these have now appeared in the Journal of Geophysical Research-Atmospheres, included in the two section sections on PEM-Tropics A. The fourth manuscript has just recently been submitted to this same journal as a stand alone paper. All four of these papers are included in this report. The first paper (Influence of biomass combustion emissions on the distribution of acidic trace gases over the Southern Pacific basin during austral springtime) describes the large-scale distributions of HNO3, HCOOH, and CH3COOH. Arguments were presented to show, particularly in the middle tropospheric region, that biomass burning emissions from South America and Africa were a major source of acidic gases over the South Pacific basin. The second paper (Aerosol chemical composition and distribution during the Pacific Exploratory Mission (PEM) Tropics) covers the aerosol aspects of our measurement package. Compared to acidic gases, O3, and selected hydrocarbons, the aerosol chemistry showed little influence from biomass burning emissions. The data collected in the marine boundary layer showed a possible marine source of NH3 to the troposphere in equatorial areas. This source had been speculated on previously, but our data was the first collected from an airborne platform to show its large-scale features. The third paper (Constraints on the age and dilution of Pacific Exploratory Mission-Tropics biomass burning plumes from the natural radionuclide tracer Pb-210) utilized the unexpectedly

  4. Organic Halogen and Related Trace Gases in the Tropical Atmosphere: Results from Recent Airborne Campaigns Over the Pacific

    NASA Astrophysics Data System (ADS)

    Atlas, E. L.; Navarro, M. A.; Donets, V.; Schauffler, S.; Lueb, R.; Hendershot, R.; Gabbard, S.; Hornbrook, R. S.; Apel, E. C.; Riemer, D. D.; Pan, L.; Salawitch, R. J.; Nicely, J. M.; Montzka, S. A.; Miller, B.; Moore, F. L.; Elkins, J. W.; Hintsa, E. J.; Campos, T. L.; Quack, B.; Zhu, X.; Pope, L.

    2014-12-01

    Organic halogen gases, especially containing bromine and iodine, play a significant role as precursors to active halogen chemistry and ozone catalytic loss. Much of the reactive organic halogen originates from biological processes in the surface ocean, which can be quite variable by season and location. The tropics and coastal margins are potentially important sources that are being examined. The recent coordinated CONTRAST/ATTREX/CAST missions were conducted in the Western Tropical Pacific, a region that is a major transport pathway for tropospheric air entering the stratosphere. One of the goals of the missions was to identify sources, distributions, and transport of organic halogens from the ocean surface into the tropical lower stratosphere. The missions were conducted during the NH winter season, Jan-Feb, 2014. In this presentation, we will discuss the distributions and variability of organic halogen gases in the study region and will examine the input of organic halogen species into the Tropical Tropopause Layer (TTL). Comparison with other tracers, such as methyl nitrate and NMHC, will help identify source regions for these gases. We will focus on the measurements obtained in the CONTRAST and ATTREX missions with data from in-situ GC/MS measurements and whole air samples collected on the NSF GV and NASA Global Hawk aircraft. Comparisons with other recent airborne campaigns, such as HIPPO and TC4, and with several ship-based studies will provide an additional context for evaluating the variability of organic halogen species in the tropical atmosphere and their role in transporting reactive halogen compounds into the UT/LS.

  5. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  6. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  7. Spatial Variation of Methane and Other Trace Gases Detected on Mars: Interpretation with a General Circulation Model

    NASA Technical Reports Server (NTRS)

    Forget, F.; Haberle, B.; Montmessin, F.

    2005-01-01

    Several teams have recently reported the detection of methane in the Martian atmosphere [1-3]. Although the detection is at the limit of the instrument capacities, one of the most surprising findings by some of these teams is the apparent strong spatial variations observed in spite of the fact that a gas like methane was expected to have a relatively long lifetime in the Martian atmosphere and thus be well mixed. To better quantitatively understand how such spatial variations can form on Mars, we have performed multiple realistic 3D general circulation model simulations in which gases with different sources, lifetime or sinks are released and transported in the Martian atmosphere.

  8. High resolution imaging Fourier transform spectrometer with no moving components for the measurement of atmospheric trace gases

    NASA Astrophysics Data System (ADS)

    Mortimer, H.

    2014-12-01

    A high resolution Static Imaging Fourier Transform Spectrometer, SIFTS, with no moving parts has been developed for the detection of atmospheric gases. The instrument has been shown to have high spectral resolution (4 cm-1) and temporal resolution (10kHz) resolution in both the mid and near infrared and moderate spectral resolution (14cm-1) in the visible. This instrument has been developed for the remote sensing and in-situ measurements of atmospheric gases. It has been identified that due to the low mass and compact size of the instrument system, that the SIFTS could be deployed as a remote sensing instrument onboard a Earth Observation satellite or Unmanned Aerial Vehicle (UAV), or conversely as a radiosonde instrument for in-situ measurements of atmospheric gases. The technique is based on a static optical configuration whereby light is split into two paths and made to recombine along a focal plane producing an interference pattern. The spectral information is returned using a detector array to digitally capture the interferogram which can then be processed into a spectrum by applying a Fourier transform. As there are no moving components, the speed of measurement is determined by the frame rate of the detector array. Thus, this instrument has a temporal advantage over common Michelson FTIR instruments. Using a high speed Toshiba CCD line array, sensitive over the spectral region of 400 - 1100nm, spectra have been recorded at a rate of one every 100 microseconds. Using an uncooled microbolometer infrared detector array, sensitive over the spectral region of 2 to 15μm, the gases NH3, O3 and CH4 have been used to demonstrate the sensitivity of the SIFTS instrument. It has been shown that the Signal to Noise of the SIFTSMIR is >1200 using an integration time of 77msec. The novel optical design has reduced the optics to only 3 optical components, and the detector array, to generate and measure the interferogram. The experimental performance of the SIFTS instrument

  9. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

    NASA Astrophysics Data System (ADS)

    Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.

    2015-02-01

    A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud-aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it is anticipated

  10. Tunable diode laser based, one component instrument for open path measurements of trace concentrations of atmospheric gases

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. I.; Nadezhdinskij, A. I.; Stepanov, E. V.; Blokh, M. A.

    1993-02-01

    A simple tunable diode laser based system for routine monitoring of concentrations of atmospheric gases was developed. The instrument operation is based on a PbSnSe diode laser emitting radiation at about 4.7 microns, and InSb photodiodes. Usually, the laser operates in multimode regime with an optical power of about 0.1 mW in the mode. The system consists of the emitter-receiver unit (including optical elements and a cryostat with liquid nitrogen, which contains the diode laser and two InSb photodetectors) and the retroreflector. The instrument has two limitations: (1) the gas should have absorption lines within the mid-IR spectral region (4-8 microns) and (2) the gas should be stable enough while in the instrument's cell to allow periodic calibration of the instument. The instrument, which in the manufacturing stage, is presently used for carbon monoxide monitoring.

  11. EDDY RESOLVING NUTRIENT ECODYNAMICS IN THE GLOBAL PARALLEL OCEAN PROGRAM AND CONNECTIONS WITH TRACE GASES IN THE SULFUR, HALOGEN AND NMHC CYCLES

    SciTech Connect

    S. CHU; S. ELLIOTT

    2000-08-01

    Ecodynamics and the sea-air transfer of climate relevant trace gases are intimately coupled in the oceanic mixed layer. Ventilation of species such as dimethyl sulfide and methyl bromide constitutes a key linkage within the earth system. We are creating a research tool for the study of marine trace gas distributions by implementing coupled ecology-gas chemistry in the high resolution Parallel Ocean Program (POP). The fundamental circulation model is eddy resolving, with cell sizes averaging 0.15 degree (lat/long). Here we describe ecochemistry integration. Density dependent mortality and iron geochemistry have enhanced agreement with chlorophyll measurements. Indications are that dimethyl sulfide production rates must be adjusted for latitude dependence to match recent compilations. This may reflect the need for phytoplankton to conserve nitrogen by favoring sulfurous osmolytes. Global simulations are also available for carbonyl sulfide, the methyl halides and for nonmethane hydrocarbons. We discuss future applications including interaction with atmospheric chemistry models, high resolution biogeochemical snapshots and the study of open ocean fertilization.

  12. An evaluation of trace element release associated with acid mine drainage

    SciTech Connect

    Sullivan, P.J.; Yelton, J.L. )

    1988-12-01

    The determination of trace element release from geologic materials, such as oil shale and coal overburden, is important for proper solid waste management planning. The objective of this study was to determine a correlation between release using the following methods: (1) sequential selective dissolution for determining trace element residencies, (2) toxicity characteristic leaching procedure (TCLP), and (3) humidity cell weathering study simulating maximum trace element release. Two eastern oil shales were used, a New Albany shale that contains 4.6 percent pyrite, and a Chattanooga shale that contains 1.5 percent pyrite. Each shale was analyzed for elemental concentrations by soluble, adsorbed, organic, carbonate, and sulfide phases. The results of the results of the selective dissolution studies show that each trace element has a unique distribution between the various phases. Thus, it is possible to predict trace element release based on trace element residency. The TCLP results show that this method is suitable for assessing soluble trace element release but does not realistically assess potential hazards. The results of the humidity cell studies do demonstrate a more reasonable method for predicting trace element release and potential water quality hazards. The humidity cell methods, however, require months to obtain the required data with a large number of analytical measurements. When the selective dissolution data are compared to the trace element concentrations in the TCLP and humidity cell leachates, it is shown that leachate concentrations are predicted by the selective dissolution data. Therefore, selective dissolution may represent a rapid method to assess trace element release associated with acid mine drainage.

  13. Water and acid soluble trace metals in atmospheric particles

    NASA Technical Reports Server (NTRS)

    Lindberg, S. E.; Harriss, R. C.

    1983-01-01

    Continental aerosols are collected above a deciduous forest in eastern Tennessee and subjected to selective extractions to determine the water-soluble and acid-leachable concentrations of Cd, Mn, Pb, and Zn. The combined contributions of these metals to the total aerosol mass is 0.5 percent, with approximately 70 percent of this attributable to Pb alone. A substantial fraction (approximately 50 percent or more) of the acid-leachable metals is soluble in distilled water. In general, this water-soluble fraction increases with decreasing particle size and with increasing frequency of atmospheric water vapor saturation during the sampling period. The pattern of relative solubilities (Zn being greater than Mn, which is approximately equal to Cd, which is greater than Pb) is found to be similar to the general order of the thermodynamic solubilities of the most probable salts of these elements in continental aerosols with mixed fossil fuel and soil sources.

  14. [Determination of trace haloacetic acids in drinking water using ion chromatography coupled with solid phase extraction].

    PubMed

    Sun, Yingxue; Huang, Jianjun; Gu, Ping

    2006-05-01

    The combined solid phase extraction (SPE)-ion chromatography (IC) method was developed for the analysis of trace haloacetic acids (HAAs) in drinking water. The tested HAAs included monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA). For trace determination of HAAs in real drinking water samples, conditions of LiChrolut EN SPE cartridge were investigated for HAAs preconcentration and matrix elimination. Elution was carried out by 2 mL of sodium hydroxide (10 mmol/L) with the flow rate of 2 mL/min. The Dionex IonPac AS16 column (250 mm x 4 mm i. d.), a high capacity and hydroxide-selective anion-exchange column designed for the determination of polarizable anions, was chosen for chromatographic separation. HAAs were analyzed with a concentration gradient of NaOH with the flow rate of 0.8 mL/min and detected by suppressed conductivity. A 500 microL sample loop was used. The detection limits of this SPE-IC method for MCAA, DCAA, DBAA and TCAA were 0.38-1.69 microg/L and MBAA was 12.5 microg/L under 25-fold preconcentration. The results demonstrate that the method is suitable for the analysis of trace haloacetic acids in drinking water.

  15. 40 CFR 60.54a - Standard for municipal waste combustor acid gases.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... affected facility any gases that contain hydrogen chloride in excess of 5 percent of the potential hydrogen chloride emission rate (95 percent reduction by weight or volume) or 25 parts per million by...

  16. 40 CFR 60.54a - Standard for municipal waste combustor acid gases.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affected facility any gases that contain hydrogen chloride in excess of 5 percent of the potential hydrogen chloride emission rate (95 percent reduction by weight or volume) or 25 parts per million by...

  17. 40 CFR 60.54a - Standard for municipal waste combustor acid gases.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affected facility any gases that contain hydrogen chloride in excess of 5 percent of the potential hydrogen chloride emission rate (95 percent reduction by weight or volume) or 25 parts per million by...

  18. 40 CFR 60.54a - Standard for municipal waste combustor acid gases.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... affected facility any gases that contain hydrogen chloride in excess of 5 percent of the potential hydrogen chloride emission rate (95 percent reduction by weight or volume) or 25 parts per million by...

  19. 40 CFR 60.54a - Standard for municipal waste combustor acid gases.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... affected facility any gases that contain hydrogen chloride in excess of 5 percent of the potential hydrogen chloride emission rate (95 percent reduction by weight or volume) or 25 parts per million by...

  20. High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

    2015-02-01

    In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants. PMID:25465511

  1. High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

    2015-02-01

    In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants.

  2. Dating and tracing groundwater resources in central Québec with noble gases, 14C and water chemistry

    NASA Astrophysics Data System (ADS)

    Vautour, G.; Pinti, D. L.; Castro, M. C.; Barbecot, F.; Larocque, M.; Hall, C. M.

    2011-12-01

    Canada water supply is derived mainly from lakes and rivers while groundwater accounts for less than 30% of the demand. Climatic and anthropogenic stress is endangering this natural resource. This study is part of a Quebec-funded program to characterize groundwater resources from major basins to ensure adequate water quality and management. The Bécancour River catchment area, 200 km NE of Montréal, is studied for this purpose. The region extends from the Appalachian Mts. down to the St. Lawrence River. Water chemistry shows the occurrence of Ca,Na-HCO3, Ca-HCO3, Na-HCO3 and NaCl waters, mainly recharged in the Appalachians and flowing to the St. Lawrence River. Aquifers are also recharged locally through Quaternary sandy deposits throughout the plain. Main aquifers are found both in unconfined and confined Quaternary sands intercalated with clays, and also locally in fractured Ordovician carbonates. To identify groundwater flow paths and to estimate water residence times, a multi-isotopic study involving noble gases, 14C and U, Th isotopes was initiated. Noble gas preliminary results were obtained on two transects, one along the downward flow path and the second perpendicular to the first, along a deeper sinclinorium with NaCl waters (TDS =170-705 mg/L). The 3He/4He ratios versus 4He/20Ne clearly points to mixing between three water bodies. The first has been recharged very recently displaying a near-atmospheric ratio of 0.79 Ra (Ra=atmospheric 3He/4He ratio of 1.386 x 10-6) and a 4He/20Ne of 0.2 close to the Air Saturated Water value, i.e. the ratio of atmospheric He and Ne dissolved in groundwater. The second water body is slightly older and shows the occurrence of tritiogenic 3He (3Hetri) excesses up to 1.07x10-13 ccSTP/g. These waters are found along the transect parallel to the main flow path. Using a local tritium decay curve and measured 3Hetri, an age of 19-20 years is suggested. The third water body contains large amounts of radiogenic 4He produced by U

  3. CONTRACE - Convective transport of trace gases into the middle and upper troposphere over Europe: Budget and impact on chemistry

    NASA Astrophysics Data System (ADS)

    Huntrieser, H.; Contrace Team

    2003-04-01

    The objective of the CONTRACE project is to investigate the impact of convective transported (and/or frontal lifting of) air masses from the boundary layer on the trace gas composition and budget in the middle and upper troposphere over Europe. The first airborne field experiment was carried out from Southern Germany in fall 2001. The DLR research aircraft Falcon was equipped with a complex instrumentation to measure NO, NOy, CO, CO2, O3, J(NO2), acetone, SO2, ions, H2O2, formaldehyde, NMHC, J(O1D) and particles. An extensive set of chemical and meteorological forecast products, including trajectory calculations, was developed and used in combination with satellite images (METEOSAT and GOES) to plan the flights. A passive tracer for surface emissions (CO) was included in the forecast models to separate the regional and intercontinental transport of polluted air masses. During all CONTRACE flights in the free troposphere polluted layers with different origin (European/North American) and distinctly enhanced trace gas mixing ratios (especially NOy and CO) were successfully observed. On November 14th the chemical forecast models indicated lifting of surface emissions in the Mediterranean area ahead of a cold front system that passed over Central and Southern Europe. The airborne measurements showed that these emissions were lifted up to 3 km altitude over Corsica. Further, several pollution layers were found in the middle and upper troposphere (4-7 km) over Corsica. The outflow from nearby thunderstorms to west probably caused these enhancements in the CO (120 ppbv), NO (1.5 ppbv) and NOy (3 ppbv) signals. For the first time it succeeded to guide the Falcon aircraft very precisely into pollution plumes transported all the way from North America. Until now these plumes had only been observed by coincidence. The forecast models showed how pollution plumes were lifted over Eastern North America, ahead of approaching cold fronts, in so-called warm conveyor belts (WCB) and

  4. Extraterrestrial Amino Acids in Orgueil and Ivuna: Tracing the Parent Body of CI Type Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Meyer, Michael (Technical Monitor); Ehrenfreund, Pascale; Glavin, Daniel P.; Bota, Oliver; Cooper, George; Bada, Jeffrey

    2001-01-01

    Amino acid analyses using HPLC of pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna have found that beta-alanine, glycine, and gamma-amino-n-butyric acid (ABA) are the most abundant amino acids in these two meteorites, with concentrations ranging from approx. 600 to 2,000 parts per billion (ppb). Other alpha-amino acids such as alanine, alpha-ABA, alpha-aminoisobutyric acid (AIB), and isovaline are present only in trace amounts (less than 200 ppb). Carbon isotopic measurements of beta-alanine and glycine and the presence of racemic (D/L 1) alanine and beta-ABA in Orgueil suggest that these amino acids are extraterrestrial in origin. In comparison to the CM carbonaceous chondrites Murchison and Murray, the amino acid composition of the CIs is strikingly distinct, suggesting that these meteorites came from a different type of parent body, possibly an extinct comet, than did the CM carbonaceous chondrites.

  5. Extraterrestrial amino acids in Orgueil and Ivuna: Tracing the parent body of CI type carbonaceous chondrites

    PubMed Central

    Ehrenfreund, Pascale; Glavin, Daniel P.; Botta, Oliver; Cooper, George; Bada, Jeffrey L.

    2001-01-01

    Amino acid analyses using HPLC of pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna have found that β-alanine, glycine, and γ-amino-n-butyric acid (ABA) are the most abundant amino acids in these two meteorites, with concentrations ranging from ≈600 to 2,000 parts per billion (ppb). Other α-amino acids such as alanine, α-ABA, α-aminoisobutyric acid (AIB), and isovaline are present only in trace amounts (<200 ppb). Carbon isotopic measurements of β-alanine and glycine and the presence of racemic (D/L ≈ 1) alanine and β-ABA in Orgueil suggest that these amino acids are extraterrestrial in origin. In comparison to the CM carbonaceous chondrites Murchison and Murray, the amino acid composition of the CIs is strikingly distinct, suggesting that these meteorites came from a different type of parent body, possibly an extinct comet, than did the CM carbonaceous chondrites. PMID:11226205

  6. Investigation of reactions between trace gases and functional CuO nanospheres and octahedrons using NEXAFS-TXM imaging

    NASA Astrophysics Data System (ADS)

    Henzler, Katja; Heilemann, Axel; Kneer, Janosch; Guttmann, Peter; Jia, He; Bartsch, Eckhard; Lu, Yan; Palzer, Stefan

    2015-12-01

    In order to take full advantage of novel functional materials in the next generation of sensorial devices scalable processes for their fabrication and utilization are of great importance. Also understanding the processes lending the properties to those materials is essential. Among the most sought-after sensor applications are low-cost, highly sensitive and selective metal oxide based gas sensors. Yet, the surface reactions responsible for provoking a change in the electrical behavior of gas sensitive layers are insufficiently comprehended. Here, we have used near-edge x-ray absorption fine structure spectroscopy in combination with x-ray microscopy (NEXAFS-TXM) for ex-situ measurements, in order to reveal the hydrogen sulfide induced processes at the surface of copper oxide nanoparticles, which are ultimately responsible for triggering a percolation phase transition. For the first time these measurements allow the imaging of trace gas induced reactions and the effect they have on the chemical composition of the metal oxide surface and bulk. This makes the new technique suitable for elucidating adsorption processes in-situ and under real operating conditions.

  7. Investigation of reactions between trace gases and functional CuO nanospheres and octahedrons using NEXAFS-TXM imaging.

    PubMed

    Henzler, Katja; Heilemann, Axel; Kneer, Janosch; Guttmann, Peter; Jia, He; Bartsch, Eckhard; Lu, Yan; Palzer, Stefan

    2015-01-01

    In order to take full advantage of novel functional materials in the next generation of sensorial devices scalable processes for their fabrication and utilization are of great importance. Also understanding the processes lending the properties to those materials is essential. Among the most sought-after sensor applications are low-cost, highly sensitive and selective metal oxide based gas sensors. Yet, the surface reactions responsible for provoking a change in the electrical behavior of gas sensitive layers are insufficiently comprehended. Here, we have used near-edge x-ray absorption fine structure spectroscopy in combination with x-ray microscopy (NEXAFS-TXM) for ex-situ measurements, in order to reveal the hydrogen sulfide induced processes at the surface of copper oxide nanoparticles, which are ultimately responsible for triggering a percolation phase transition. For the first time these measurements allow the imaging of trace gas induced reactions and the effect they have on the chemical composition of the metal oxide surface and bulk. This makes the new technique suitable for elucidating adsorption processes in-situ and under real operating conditions. PMID:26631608

  8. An automated analyzer to measure surface-atmosphere exchange fluxes of water soluble inorganic aerosol compounds and reactive trace gases.

    PubMed

    Thomas, Rick M; Trebs, Ivonne; Otjes, René; Jongejan, Piet A C; Ten Brink, Harry; Phillips, Gavin; Kortner, Michael; Meixner, Franz X; Nemitz, Eiko

    2009-03-01

    Here, we present a new automated instrument for semicontinuous gradient measurements of water-soluble reactive trace gas species (NH3, HNO3, HONO, HCl, and SO2) and their related aerosol compounds (NH4+, NO3-, Cl-, SO4(2-)). Gas and aerosol samples are collected simultaneously at two heights using rotating wet-annular denuders and steam-jet aerosol collectors, respectively. Online (real-time) analysis using ion chromatography (IC) for anions and flow injection analysis (FIA) for NH4+ and NH3 provide a half-hourly averaged gas and aerosol gradients within each hour. Through the use of syringe pumps, IC preconcentration columns, and high-quality purified water, the system achieves detection limits (3sigma-definition) under field conditions of typically: 136/207,135/114, 29/ 22,119/92, and 189/159 ng m(-3) for NH3/NH4+, HNO3/NO3-, HONO/ NO2-, HCl/Cl- and SO2/SO4(2-), respectively. The instrument demonstrates very good linearity and accuracy for liquid and selected gas phase calibrations over typical ambient concentration ranges. As shown by examples from field experiments, the instrument provides sufficient precision (3-9%), even at low ambient concentrations, to resolve vertical gradients and calculate surface-atmosphere exchange fluxes undertypical meteorological conditions of the atmospheric surface layer using the aerodynamic gradient technique. PMID:19350912

  9. Investigation of reactions between trace gases and functional CuO nanospheres and octahedrons using NEXAFS-TXM imaging

    PubMed Central

    Henzler, Katja; Heilemann, Axel; Kneer, Janosch; Guttmann, Peter; Jia, He; Bartsch, Eckhard; Lu, Yan; Palzer, Stefan

    2015-01-01

    In order to take full advantage of novel functional materials in the next generation of sensorial devices scalable processes for their fabrication and utilization are of great importance. Also understanding the processes lending the properties to those materials is essential. Among the most sought-after sensor applications are low-cost, highly sensitive and selective metal oxide based gas sensors. Yet, the surface reactions responsible for provoking a change in the electrical behavior of gas sensitive layers are insufficiently comprehended. Here, we have used near-edge x-ray absorption fine structure spectroscopy in combination with x-ray microscopy (NEXAFS-TXM) for ex-situ measurements, in order to reveal the hydrogen sulfide induced processes at the surface of copper oxide nanoparticles, which are ultimately responsible for triggering a percolation phase transition. For the first time these measurements allow the imaging of trace gas induced reactions and the effect they have on the chemical composition of the metal oxide surface and bulk. This makes the new technique suitable for elucidating adsorption processes in-situ and under real operating conditions. PMID:26631608

  10. Physical and chemical properties of the regional mixed layer of Mexico's Megapolis – Part II: Evaluation of measured and modeled trace gases and particle size distributions

    SciTech Connect

    Ochoa, Carlos; Baumgardner, Darrel; Grutter, M.; Allan, James D.; Fast, Jerome D.; Rappengluck, B.

    2012-10-31

    This study extends the work of Baumgardner et al. (2009) in which measurements of trace gases and particles at a remote, high-altitude mountain site 60 km from Mexico City were analyzed with respect to the origin of air masses. In the current evaluation, the temperature, water vapor, ozone (O3), carbon monoxide (CO), acyl peroxy nitrate (APN) and particle size distributions (PSDs) of the mass concentrations of sulfate, nitrate, ammonium and organic mass (OM) were simulated with the WRF-Chem chemical transport model and compared with the measurements at the mountain site. The model prediction of the diurnal trends of the gases were well correlated with the measurements before the regional boundary layer reached the measurement site but underestimated the concentrations after that time. The differences are caused by an overly rapid growth of the boundary layer by the model with too much dilution. There also appears to be more O3 produced by photochemical production, downwind of the emission sources, than predicted by the model. The measured and modeled PSDs compare very well with respect to their general shape and diameter of the peak concentrations. The spectra are log normally distributed with most of the mass in the accumulation mode and the geometric diameter centered at 200 ±20 nm, with little observed or predicted change with respect to the origin of the air mass or the time when the RBL is above the Altzomoni research. Only the total mass changed with time and air mass origin. The invariability of the average diameter of the accumulation mode suggests that there is very little growth of the particles by condensation or coagulation after six hours of aging downwind of the major sources of anthropogenic emissions in Mexico’s Megapolis.

  11. Robust IR Remote Sensing Technique of the Total Column of Trace Gases Including Carbon Dioxide and Methane

    NASA Technical Reports Server (NTRS)

    Georgieva, E. M.; Heaps, W. S.

    2011-01-01

    methane very suddenly further exacerbating climate change [2]. Last year our group began a joint effort with Johns Hopkins Applied Physics Laboratory to investigate the possibility of developing a small unmanned aerial vehicle (UAV) equipped to measure greenhouse gases-particularly methane. Although we are targeting our system for smaller UAV's the instrument will be directly applicable to missions involving larger NASA UAV's such as Global Hawk or even on missions utilizing manned aircraft. Because of its small size, inherent ruggedness and simplicity some version of our proposed instrument may find a role as a satellite instrument for NASA or NOAA.

  12. Oxidation of trace amounts of transplutonium elements to the tetravalent state in solutions of mineral acids and their stabilities

    SciTech Connect

    Milyukova, M.S.; Varezhkina, N.S.; Kuzovkina, E.V.; Malikov, D.A.; Myasoedov, B.F.

    1989-01-01

    The behavior of trace amounts of americium(IV) in sulfuric and nitric acid solutions as a function of the mineral acid, potassium phosphotungstate, and ammonium persulfate concentrations was investigated. The stability of americium(IV) was studied. The optimal conditions and time of oxidation of trace amounts of americium to the tetravalent state were found on the basis of the experimental data obtained.

  13. Emission factors of fine particles, carbonaceous aerosols and traces gases from road vehicles: Recent tests in an urban tunnel in the Pearl River Delta, China

    NASA Astrophysics Data System (ADS)

    Zhang, Yanli; Wang, Xinming; Li, Guanghui; Yang, Weiqiang; Huang, Zhonghui; Zhang, Zhou; Huang, Xinyu; Deng, Wei; Liu, Tengyu; Huang, Zuzhao; Zhang, Zhanyi

    2015-12-01

    Motor vehicles contribute primarily and secondarily to air quality problems due to fine particle (PM2.5) and ozone (O3) pollution in China's megacities. Characterizing vehicle emission with the rapid change of vehicle numbers and fleet compositions is vital for both bottom-up emission survey and top-down source apportioning. To obtain emission factors (EFs) of PM2.5, carbonaceous aerosols and trace gases for road vehicles, in urban Guangzhou we conducted a field campaign in 2014 in the Zhujiang Tunnel, a heavily burdened tunnel with about 40,000 motor vehicles passing through each of its two separated bores per day. PM2.5 and volatile organic compounds (VOCs) were sampled for offline analysis while trace gases including SO2, NOx and CO were measured online and in situ. An eddy covariance system with an integrated 3-D sonic anemometer was also adopted to measure CO2 and winds inside the tunnel. We recorded an average fleet composition of 61% light-duty gasoline vehicles (LDVs) + 12% heavy-duty diesel vehicles (HDVs) + 27% liquefied petroleum gas vehicles (LPGVs), and EFs of 82.7 ± 28.3, 19.3 ± 4.7 and 13.3 ± 3.3 mg veh-1 km-1, respectively, for PM2.5, organic carbon (OC) and elemental carbon (EC). These EFs were respectively 23.4%, 18.3% and 72.3% lower when compared to that measured in the same tunnel in 2004. EFs of PM2.5, OC and EC were higher at night time (148 ± 126, 29 ± 24 and 21 ± 18 mg veh-1 km-1, respectively) due to significantly elevated fractions of HDVs in the traffic fleets. An average ratio of OC to EC 1.45 from this tunnel study was much higher than that of ∼0.5 in previous tunnel studies. The EFs of SO2, NOx, CO, CO2 and NMHCs for road traffic were also obtained from our tunnel tests, and they were 20.7 ± 2.9, (1.29 ± 0.2)E+03, (3.10 ± 0.68)E+03, (3.90 ± 0.49)E+05, and 448 ± 39 mg veh-1 km-1, respectively.

  14. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

    DOE PAGES

    Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.

    2015-02-24

    A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convectivemore » cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it

  15. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

    SciTech Connect

    Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.

    2015-02-24

    A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it is

  16. Airborne and ground-based measurements of the trace gases and particles emitted from prescribed fires in the United States

    SciTech Connect

    Burling, Ian; Yokelson, Robert J.; Akagi, Sheryl; Urbanski, Shawn; Wold, Cyle E.; Griffith, David WT; Johnson, Timothy J.; Reardon, James; Weise, David

    2011-12-07

    We measured the emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous suggestions that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured the emissions in the convective smoke plume from our airborne platform at the same time the unlofted residual smoldering combustion emissions were measured with our ground-based platform after the flame front passed through. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including significant 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts of smoke that disperses at ground level, and we show that the normally-ignored unlofted emissions can also significantly impact estimates of total emissions. Preliminary evidence of large emissions of monoterpenes was seen in the residual smoldering spectra, but we have not yet quantified these emissions. These data should lead to an improved capacity to model the impacts of biomass burning in similar

  17. Airborne and ground-based measurements of the trace gases and particles emitted by prescribed fires in the United States

    NASA Astrophysics Data System (ADS)

    Burling, I. R.; Yokelson, R. J.; Akagi, S. K.; Urbanski, S. P.; Wold, C. E.; Griffith, D. W. T.; Johnson, T. J.; Reardon, J.; Weise, D. R.

    2011-12-01

    We have measured emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps to close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts for smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems.

  18. Coupling field and laboratory measurements to estimate the emission factors of identified and unidentified trace gases for prescribed fires

    SciTech Connect

    Yokelson, R. J.; Burling, I. R.; Gilman, J. B.; Warneke, C.; Stockwell, C. E.; de Gouw, J.; Akagi, S. K.; Urbanski, S. P.; Veres, P.; Roberts, J. M.; Kuster, W. C.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Hosseini, S.; Miller, J. W.; Cocker III, D. R.; Jung, H.; Weise, D. R.

    2013-01-01

    Vegetative fuels commonly consumed in prescribed fires were collected from five locations in the southeastern and southwestern U.S. and burned in a series of 77 fires at the U.S. Forest Service Fire Sciences Laboratory in Missoula, Montana. The particulate matter (PM2.5) emissions were measured by gravimetric filter sampling with subsequent analysis for elemental carbon (EC), organic carbon (OC), and 38 elements. The trace gas emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP FTIR) spectrometer, proton-transfer-reaction mass spectrometry (PTR-MS), proton-transfer ion-trap mass spectrometry (PIT-MS), negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), and gas chromatography with MS detection (GC-MS). 204 trace gas species (mostly non-methane organic compounds (NMOC)) were identified and quantified with the above instruments. An additional 152 significant peaks in the unit mass resolution mass spectra were quantified, but either could not be identified or most of the signal at that molecular mass was unaccounted for by identifiable species. As phase II of this study, we conducted airborne and ground-based sampling of the emissions from real prescribed fires mostly in the same land management units where the fuels for the lab fires were collected. A broad variety, but smaller number of species (21 trace gas species and PM2.5) was measured on 14 fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. These extensive field measurements of emission factors (EF) for temperate biomass burning are useful both for modeling and to examine the representativeness of our lab fire EF. The lab/field EF ratio for the pine understory fuels was not statistically different from one, on average. However, our lab EF for “smoldering compounds” emitted by burning the semi

  19. Coupling field and laboratory measurements to estimate the emission factors of identified and unidentified trace gases for prescribed fires

    NASA Astrophysics Data System (ADS)

    Yokelson, R. J.; Burling, I. R.; Gilman, J. B.; Warneke, C.; Stockwell, C. E.; de Gouw, J.; Akagi, S. K.; Urbanski, S. P.; Veres, P.; Roberts, J. M.; Kuster, W. C.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Hosseini, S.; Miller, J. W.; Cocker, D. R., III; Jung, H.; Weise, D. R.

    2013-01-01

    An extensive program of experiments focused on biomass burning emissions began with a laboratory phase in which vegetative fuels commonly consumed in prescribed fires were collected in the southeastern and southwestern US and burned in a series of 71 fires at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The particulate matter (PM2.5) emissions were measured by gravimetric filter sampling with subsequent analysis for elemental carbon (EC), organic carbon (OC), and 38 elements. The trace gas emissions were measured by an open-path Fourier transform infrared (OP-FTIR) spectrometer, proton-transfer-reaction mass spectrometry (PTR-MS), proton-transfer ion-trap mass spectrometry (PIT-MS), negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), and gas chromatography with MS detection (GC-MS). 204 trace gas species (mostly non-methane organic compounds (NMOC)) were identified and quantified with the above instruments. Many of the 182 species quantified by the GC-MS have rarely, if ever, been measured in smoke before. An additional 153 significant peaks in the unit mass resolution mass spectra were quantified, but either could not be identified or most of the signal at that molecular mass was unaccounted for by identifiable species. In a second, "field" phase of this program, airborne and ground-based measurements were made of the emissions from prescribed fires that were mostly located in the same land management units where the fuels for the lab fires were collected. A broad variety, but smaller number of species (21 trace gas species and PM2.5) was measured on 14 fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. The field measurements of emission factors (EF) are useful both for modeling and to examine the representativeness of our lab fire EF. The lab EF/field EF ratio for the pine understory fuels was not

  20. Coupling field and laboratory measurements to estimate the emission factors of identified and unidentified trace gases for prescribed fires

    NASA Astrophysics Data System (ADS)

    Yokelson, R. J.; Burling, I. R.; Gilman, J. B.; Warneke, C.; Stockwell, C. E.; de Gouw, J.; Akagi, S. K.; Urbanski, S. P.; Veres, P.; Roberts, J. M.; Kuster, W. C.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Hosseini, S.; Miller, J. W.; Cocker, D. R., III; Jung, H.; Weise, D. R.

    2012-08-01

    An extensive program of experiments focused on biomass burning emissions began with a laboratory phase in which vegetative fuels commonly consumed in prescribed fires were collected in the southeastern and southwestern US and burned in a series of 71 fires at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The particulate matter (PM2.5) emissions were measured by gravimetric filter sampling with subsequent analysis for elemental carbon (EC), organic carbon (OC), and 38 elements. The trace gas emissions were measured by an open-path Fourier transform infrared (OP-FTIR) spectrometer, proton-transfer-reaction mass spectrometry (PTR-MS), proton-transfer ion-trap mass spectrometry (PIT-MS), negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), and gas chromatography with MS detection (GC-MS). 204 trace gas species (mostly non-methane organic compounds - NMOC) were identified and quantified with the above instruments. Many of the 182 species quantified by the GC-MS have rarely, if ever, been measured in smoke before. An additional 153 significant peaks in the unit mass resolution mass spectra were quantified, but either could not be identified or most of the signal at that molecular mass was unaccounted for by identifiable species. In a second, "field" phase of this program, airborne and ground-based measurements were made of the emissions from prescribed fires that were mostly located in the same land management units where the fuels for the lab fires were collected. A broad variety, but smaller number of species (21 trace gas species and PM2.5) was measured on 14 fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. The field measurements of emission factors (EF) are useful both for modeling and to examine the representativeness of our lab fire EF. The lab EF/field EF ratio for the pine understory fuels was not

  1. Measurement of trace gases and organic compounds in the smoke plume from a wildfire in Penedono (central Portugal)

    NASA Astrophysics Data System (ADS)

    Vicente, Ana; Alves, Célia; Monteiro, Cristina; Nunes, Teresa; Mirante, Fátima; Evtyugina, Margarita; Cerqueira, Mário; Pio, Casimiro

    2011-09-01

    Gas and particulate fractions were measured simultaneously from a wildfire in Penedono, central Portugal, which occurred in summer 2009. The total volatile hydrocarbons (THC) and carbon oxides (CO 2 and CO) collected in Tedlar bags were measured using automatic analysers with flame ionisation and non-dispersive infrared detectors, respectively. Carbonyls (formaldehyde and acetaldehyde) were sampled from the Tedlar bags in DNHP cartridges and analysed by high-performance liquid chromatography. Fine (PM 2.5) and coarse (PM 2.5-10) smoke particles were collected sequentially, on pre-fired quartz fibre filters, with a portable high-volume sampler. The detailed speciation of organic compounds in smoke samples was carried out by gas chromatography-mass spectrometry. The organic and elemental carbon content of particulate matter was analysed by a thermal-optical transmission technique. Average emission factors of 1.86 ± 0.80 and 0.063 ± 0.066 g kg -1 (dry basis) were obtained for acetaldehyde and formaldehyde, respectively. The THC, CO, CO 2, PM 2.5, PM 10, OC and EC emission factors (g kg -1 fuel burned, dry basis) were 260 ± 88, 268 ± 92, 1200 ± 172, 37 ± 12.2, 40 ± 12.6, 21 ± 6.7 and 0.44 ± 0.21, respectively. The chromatographically resolved organics included n-alkanes, n-alkenes, n-alkanoic acids, n-di-acids, unsaturated fatty acids, phenolic compounds, ketones, steroids, di- and triterpenoids, PAHs, with retene as the major compound, oxygenated PAH and anhydrosugars.

  2. Determination of trace amount of oxalic acid with zirconium(IV)-(DBS-arsenazo) by spectrophotometry

    NASA Astrophysics Data System (ADS)

    Zhai, Qing-Zhou

    2008-11-01

    A novel method is proposed for the determination of trace amount of oxalic acid in the present article. In 1.0 M hydrochloric acid medium, oxalic acid can react with the zirconium(IV) in Zr(IV)-(DBS-arsenazo) complex and replaces the DBS-arsenazo to produce a hyperchromic effect at 520 nm. The hyperchromic degree is proportional to the concentration of the oxalic acid added over a defined range. Based on this property, a new method for the spectrophotometric determination of trace oxalic acid was developed. Beer's law is held over the concentration range of 9.0 × 10 -6 to 5.0 × 10 -4 M for oxalic acid with a correlation coefficient of 0.9995. The apparent molar absorptivity of the method is ɛ520 nm = 1.16 × 10 3 L mol -1 cm -1 and the detection limit for oxalic acid is 0.815 μg/mL. The developed method was directly applied to the determination of oxalic acid in tomato samples with satisfactory results.

  3. Efficient enantioselective separation and determination of trace impurities in secondary amino acids (i.e., imino acids).

    PubMed

    Zukowski, J; Pawlowska, M; Armstrong, D W

    1992-10-01

    An R-(-)-1-(1-naphthyl)ethyl carbamoylated-beta-cyclodextrin bonded phase in conjunction with a nonaqueous polar mobile phase was used for the highly selective enantioseparation of a number of secondary amino acids after their pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC). Under the conditions employed, the FMOC reagent served to "lock" the imino acid into their existing conformation thereby preventing the possibility of racemization. Furthermore, it served to increase the sensitivity to the point that trace level enantiomeric impurities were easily detected. Compared with separations that use traditional reversed-phase solvents, this method showed several advantages: higher selectivity towards the imino acid enantiomers investigated, shorter analysis times, faster equilibration of the column, more stable baseline and more sensitive fluorescence detection. The detection limits for FMOC derivatives of proline, trans-4-hydroxyproline, cis-4-hydroxyproline, pyroglutamic acid, 3,4-dehydroproline, thiaproline, penicillamine acetone adduct and pipecolic acid are in the low femtomole range. The method was used for evaluation of enantioselectivity of a number of "optically pure" commercial imino acid standards. Enantiomeric impurities as low as 0.0001% (1 ppm) can be determined in some cases. High precision determination of trace levels of D-imino acids in the presence of large amounts of corresponding (opposite) L enantiomer at 1, 0.1, 0.01% and below are demonstrated. PMID:1452629

  4. Effects of land use on surface–atmosphere exchanges of trace gases and energy in Borneo: comparing fluxes over oil palm plantations and a rainforest

    PubMed Central

    Fowler, David; Nemitz, Eiko; Misztal, Pawel; Di Marco, Chiara; Skiba, Ute; Ryder, James; Helfter, Carole; Cape, J. Neil; Owen, Sue; Dorsey, James; Gallagher, Martin W.; Coyle, Mhairi; Phillips, Gavin; Davison, Brian; Langford, Ben; MacKenzie, Rob; Muller, Jennifer; Siong, Jambery; Dari-Salisburgo, Cesare; Di Carlo, Piero; Aruffo, Eleonora; Giammaria, Franco; Pyle, John A.; Hewitt, C. Nicholas

    2011-01-01

    This paper reports measurements of land–atmosphere fluxes of sensible and latent heat, momentum, CO2, volatile organic compounds (VOCs), NO, NO2, N2O and O3 over a 30 m high rainforest canopy and a 12 m high oil palm plantation in the same region of Sabah in Borneo between April and July 2008. The daytime maximum CO2 flux to the two canopies differs by approximately a factor of 2, 1200 mg C m−2 h−1 for the oil palm and 700 mg C m−2 h−1 for the rainforest, with the oil palm plantation showing a substantially greater quantum efficiency. Total VOC emissions are also larger over the oil palm than over the rainforest by a factor of 3. Emissions of isoprene from the oil palm canopy represented 80 per cent of the VOC emissions and exceeded those over the rainforest in similar light and temperature conditions by on average a factor of 5. Substantial emissions of estragole (1-allyl-4-methoxybenzene) from the oil palm plantation were detected and no trace of this VOC was detected in or above the rainforest. Deposition velocities for O3 to the rainforest were a factor of 2 larger than over oil palm. Emissions of nitrous oxide were larger from the soils of the oil palm plantation than from the soils of the rainforest by approximately 25 per cent. It is clear from the measurements that the large change in the species composition generated by replacing rainforest with oil palm leads to profound changes in the net exchange of most of the trace gases measured, and thus on the chemical composition of the boundary layer over these surfaces. PMID:22006962

  5. Effects of land use on surface-atmosphere exchanges of trace gases and energy in Borneo: comparing fluxes over oil palm plantations and a rainforest.

    PubMed

    Fowler, David; Nemitz, Eiko; Misztal, Pawel; Di Marco, Chiara; Skiba, Ute; Ryder, James; Helfter, Carole; Cape, J Neil; Owen, Sue; Dorsey, James; Gallagher, Martin W; Coyle, Mhairi; Phillips, Gavin; Davison, Brian; Langford, Ben; MacKenzie, Rob; Muller, Jennifer; Siong, Jambery; Dari-Salisburgo, Cesare; Di Carlo, Piero; Aruffo, Eleonora; Giammaria, Franco; Pyle, John A; Hewitt, C Nicholas

    2011-11-27

    This paper reports measurements of land-atmosphere fluxes of sensible and latent heat, momentum, CO(2), volatile organic compounds (VOCs), NO, NO(2), N(2)O and O(3) over a 30 m high rainforest canopy and a 12 m high oil palm plantation in the same region of Sabah in Borneo between April and July 2008. The daytime maximum CO(2) flux to the two canopies differs by approximately a factor of 2, 1200 mg C m(-2) h(-1) for the oil palm and 700 mg C m(-2) h(-1) for the rainforest, with the oil palm plantation showing a substantially greater quantum efficiency. Total VOC emissions are also larger over the oil palm than over the rainforest by a factor of 3. Emissions of isoprene from the oil palm canopy represented 80 per cent of the VOC emissions and exceeded those over the rainforest in similar light and temperature conditions by on average a factor of 5. Substantial emissions of estragole (1-allyl-4-methoxybenzene) from the oil palm plantation were detected and no trace of this VOC was detected in or above the rainforest. Deposition velocities for O(3) to the rainforest were a factor of 2 larger than over oil palm. Emissions of nitrous oxide were larger from the soils of the oil palm plantation than from the soils of the rainforest by approximately 25 per cent. It is clear from the measurements that the large change in the species composition generated by replacing rainforest with oil palm leads to profound changes in the net exchange of most of the trace gases measured, and thus on the chemical composition of the boundary layer over these surfaces.

  6. The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

    NASA Astrophysics Data System (ADS)

    Andreae, M. O.; Acevedo, O. C.; Araùjo, A.; Artaxo, P.; Barbosa, C. G. G.; Barbosa, H. M. J.; Brito, J.; Carbone, S.; Chi, X.; Cintra, B. B. L.; da Silva, N. F.; Dias, N. L.; Dias-Júnior, C. Q.; Ditas, F.; Ditz, R.; Godoi, A. F. L.; Godoi, R. H. M.; Heimann, M.; Hoffmann, T.; Kesselmeier, J.; Könemann, T.; Krüger, M. L.; Lavric, J. V.; Manzi, A. O.; Lopes, A. P.; Martins, D. L.; Mikhailov, E. F.; Moran-Zuloaga, D.; Nelson, B. W.; Nölscher, A. C.; Santos Nogueira, D.; Piedade, M. T. F.; Pöhlker, C.; Pöschl, U.; Quesada, C. A.; Rizzo, L. V.; Ro, C.-U.; Ruckteschler, N.; Sá, L. D. A.; de Oliveira Sá, M.; Sales, C. B.; dos Santos, R. M. N.; Saturno, J.; Schöngart, J.; Sörgel, M.; de Souza, C. M.; de Souza, R. A. F.; Su, H.; Targhetta, N.; Tóta, J.; Trebs, I.; Trumbore, S.; van Eijck, A.; Walter, D.; Wang, Z.; Weber, B.; Williams, J.; Winderlich, J.; Wittmann, F.; Wolff, S.; Yáñez-Serrano, A. M.

    2015-09-01

    The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical

  7. Analysis of motor vehicle emissions over eastern Los Angeles, California from in-situ airborne measurements of trace gases and particulates during CalNex

    NASA Astrophysics Data System (ADS)

    Pollack, I. B.; Ryerson, T. B.; Trainer, M.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Peischl, J.; Fahey, D. W.; Perring, A.; Schwarz, J. P.; Spackman, J. R.

    2010-12-01

    In-situ measurements of trace gases and particulates were acquired on the instrumented NOAA WP-3D aircraft during the CalNex (California Research at the Nexus of Air Quality and Climate Change) field study in May and June 2010. Multiple daytime research flights under similar meteorological conditions provide a sufficient data set for characterizing automobile emissions over the eastern Los Angeles (eLA) area of the South Coast air basin. Ratios of nitrogen oxides (NOx) and black carbon (BC) to carbon monoxide (CO) are used to isolate emissions of light duty vehicles from those of medium/heavy duty diesel trucks. Observations in the mixed boundary layer for the eLA area are separated according to latitude, longitude, and altitude. Industrial influences are eliminated by filtering the data according to SO2 mixing ratio and wind direction. The resulting correlations show weekday-to-weekend differences in enhancement ratios of NOx to CO and BC to CO, indicating a general tendency for higher emissions from heavy duty vehicles during the week. The CalNex data over eLA in 2010 will be compared to eLA data from a research flight in May 2002 by the WP-3D aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) field study.

  8. Study of trace gases in the Martian atmosphere: Groundbased observation using SUBARU/IRCS and development of radiative transfer model for MEX/PFS limb observation

    NASA Astrophysics Data System (ADS)

    Aoki, S.; Nakagawa, H.; Kasaba, Y.; Giuranna, M.; Geminale, A.; Sindoni, G.; Sagawa, H.; Mendrok, J.; Kasai, Y.; Formisano, V.

    2012-09-01

    We observed Martian atmosphere to investigate CH4, H2O, and HDO on 30 November 2011, 4-5 January 2012, and 12 April 2012 using SUBARU/ IRCS. This observation aims to verify CH4 on Mars, constrain its source, and investigate the distribution of H2O/HDO ratio. Our observation covered possible source areas of CH4, i.e. the areas where the extend plumes of CH4 were detected by previous groundbased and MEX/PFS observations [1,2] and the potential mud volcanism areas [3,4]. This paper will show some preliminary results. Vertical profiles of these trace gases are crucial for understanding their chemistry and transportation. Limb observations by MEX/PFS are a powerful tool to retrieve vertical profiles of H2O, CO, and CH4. For this purpose, we adapted the SARTre model, a radiative transfer code which includes multiple scattering for limb geometry observations developed for the terrestrial atmosphere [5], to the Martian atmosphere. In order to validate our model, SARTre model for Martian limb, we first compared of our synthetic spectra in nadir geometry with the result from ARS [6] which has been widely used for previous studies of MEX/PFS nadir-observation. We concluded that the difference between them is small offset (below 3%) in the spectral range between 3000 and 3030 cm-1.

  9. Predicting the toxicity of sediment-associated trace metals with simultaneously extracted trace metal: Acid-volatile sulfide concentrations and dry weight-normalized concentrations: A critical comparison

    USGS Publications Warehouse

    Long, E.R.; MacDonald, D.D.; Cubbage, J.C.; Ingersoll, C.G.

    1998-01-01

    The relative abilities of sediment concentrations of simultaneously extracted trace metal: acid-volatile sulfide (SEM:AVS) and dry weight- normalized trace metals to correctly predict both toxicity and nontoxicity were compared by analysis of 77 field-collected samples. Relative to the SEM:AVS concentrations, sediment guidelines based upon dry weight-normalized concentrations were equally or slightly more accurate in predicting both nontoxic and toxic results in laboratory tests.

  10. Demonstration of superconducting sub-millimeter-wave limb emission sounder (SMILES) for observing trace gases in the middle atmosphere using the exposed facility of the Japanese experimental module (JEM) of the international space station

    NASA Astrophysics Data System (ADS)

    Masuko, Harunobu; Manabe, Takeshi; Seta, Masumichi; Kasai, Yasuko; Ochiai, Satoshi; Irimajiri, Yoshihisa; Inatani, Junji; Ikeda, Naomi; Nishibori, Toshiyuki; Iida, Yukiei; Fujii, Yasunori

    1999-01-01

    The sub-millimeter wavelength region is advantageous for high-precision observations of trace species in the stratosphere. A Superconducting Sub-Millimeter-wave Limb Emission Sounder (SMILES) is scheduled to demonstrate the measurements of extremely faint sub-millimeter-wave emissions of the atmospheric trace gases on the Exposed Facility (EF) of the Japanese Experimental Module (JEM) of the International Space Station in 2003. The applications of superconductivity and mechanical 4K-refrigerator in space will be demonstrated in the experiment. JEM/SMILES obtains the diurnal and seasonal variability in the global three-dimensional distributions of the stratospheric trace gases for quantitative understanding of the stratospheric ozone depletion and its effect on the climate change with respect to the relationships among chemical reaction processes and their relationships with atmospheric dynamics. JEM/SMILES utilizes the 640GHz band to measure the vertical profiles of trace gases involved in the stratospheric ozone depletion such as chlorine monoxide (CLO), bromine monoxide (BrO), etc., along with atmospheric temperature. JEM/SMILES employs Superconductor-Insulator-Superconductor (SIS) mixers to improve measurement precision and spatial resolution, thereby enabling us to quantitatively understand the interactive processes between chemistry and dynamics.

  11. Condensational growth and trace species scavenging in stratospheric sulfuric acid/water aerosol droplets

    NASA Technical Reports Server (NTRS)

    Tompson, Robert V., Jr.

    1991-01-01

    Stratospheric aerosols play a significant role in the environment. The composition of aerosols is believed to be a liquid solution of sulfuric acid and water with numerous trace species. Of these trace species, ozone in particular was recognized as being very important in its role of shielding the environment from harmful ultraviolet radiation. Also among the trace species are HCl and ClONO2, the so called chlorine reservoir species and various oxides of nitrogen. The quantity of stratospheric aerosol and its particle size distribution determines, to a large degree, the chemistry present in the stratosphere. Aerosols experience 3 types of growth: nucleation, condensation, and coagulation. The application of condensation investigations to the specific problem of stratospheric aerosols is discussed.

  12. Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO2 radicals

    NASA Astrophysics Data System (ADS)

    Liang, H.; Chen, Z. M.; Huang, D.; Zhao, Y.; Li, Z. Y.

    2013-06-01

    Field measurements of atmospheric peroxides were obtained during the summer on two consecutive years over urban Beijing, and focused on the impacts of aerosols on the chemistry of peroxide compounds and hydroperoxyl radicals (HO2). The major peroxides were determined to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP), and peroxyacetic acid (PAA). A negative correlation was found between H2O2 and PAA in rainwater, providing evidence for a conversion between H2O2 and PAA in the aqueous phase. A standard gas phase chemistry model based on the NCAR Master Mechanism provided a good reproduction of the observed H2O2 profile on non-haze days but greatly overpredicted the H2O2 level on haze days. We attribute this overprediction to the reactive uptake of HO2 by the aerosols, since there was greatly enhanced aerosol loading and aerosol liquid water content on haze days. The discrepancy between the observed and modeled H2O2 can be diminished by adding to the model a newly proposed transition metal ion catalytic mechanism of HO2 in aqueous aerosols. This confirms the importance of the aerosol uptake of HO2 and the subsequent aqueous phase reactions in the reduction of H2O2. The closure of HO2 and H2O2 between the gas and aerosol phases suggests that the aerosols do not have a net reactive uptake of H2O2, because the conversion of HO2 to H2O2 on aerosols compensates for the H2O2 loss. Laboratory studies for the aerosol uptake of H2O2 in the presence of HO2 are urgently required to better understand the aerosol uptake of H2O2 in the real atmosphere.

  13. Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO2 radicals

    NASA Astrophysics Data System (ADS)

    Liang, H.; Chen, Z. M.; Huang, D.; Zhao, Y.; Li, Z. Y.

    2013-11-01

    Field measurements of atmospheric peroxides were obtained during the summer on two consecutive years over urban Beijing, which highlighted the impacts of aerosols on the chemistry of peroxide compounds and hydroperoxyl radicals (HO2). The major peroxides were determined to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP), and peroxyacetic acid (PAA). A negative correlation was found between H2O2 and PAA in rainwater, providing evidence for a conversion between H2O2 and PAA in the aqueous phase. A standard gas phase chemistry model based on the NCAR Master Mechanism provided a good reproduction of the observed H2O2 profile on non-haze days but greatly overpredicted the H2O2 level on haze days. We attribute this overprediction to the reactive uptake of HO2 by the aerosols, since there was greatly enhanced aerosol loading and aerosol liquid water content on haze days. The discrepancy between the observed and modeled H2O2 can be diminished by adding to the model a newly proposed transition metal ion catalytic mechanism of HO2 in aqueous aerosols. This confirms the importance of the aerosol uptake of HO2 and the subsequent aqueous phase reactions in the reduction of H2O2. The closure of HO2 and H2O2 between the gas and aerosol phases suggests that the aerosols do not have a net reactive uptake of H2O2, because the conversion of HO2 to H2O2 on aerosols compensates for the H2O2 loss. Laboratory studies for the aerosol uptake of H2O2 in the presence of HO2 are urgently required to better understand the aerosol uptake of H2O2 in the real atmosphere.

  14. Trends in source gases

    NASA Technical Reports Server (NTRS)

    Ehhalt, D. H.; Fraser, P. J.; Albritton, D.; Cicerone, R. J.; Khalil, M. A. K.; Legrand, M.; Makide, Y.; Rowland, F. S.; Steele, L. P.; Zander, R.

    1989-01-01

    Source gases are defined as those gases that, by their breakdown, introduce into the stratosphere halogen, hydrogen, and nitrogen compounds that are important in stratospheric ozone destruction. Given here is an update of the existing concentration time series for chlorocarbons, nitrous oxide, and methane. Also reviewed is information on halogen containing species and the use of these data for establishing trends. Also reviewed is evidence on trends in trace gases that influence tropospheric chemistry and thus the tropospheric lifetimes of source gases, such as carbon dioxide, carbon monoxide, or nitrogen oxides. Much of the information is given in tabular form.

  15. Apparatus for purifying arsine, phosphine, ammonia, and inert gases to remove Lewis acid and oxidant impurities therefrom

    DOEpatents

    Tom, Glenn M.; Brown, Duncan W.

    1991-01-08

    An apparatus for purifying a gaseous mixture comprising arsine, phosphine, ammonia, and/or inert gases, to remove Lewis acid and/or oxidant impurities therefrom, comprising a vessel containing a bed of a scavenger, the scavenger including a support having associated therewith an anion which is effective to remove such impurities, such anion being selected from one or more members of the group consisting of: (i) carbanions whose corresponding protonated compounds have a pK.sub.a value of from about 22 to about 36; and (ii) anions formed by reaction of such carbanions with the primary component of the mixture.

  16. Interaction between common organic acids and trace nucleation species in the Earth's atmosphere.

    PubMed

    Xu, Yisheng; Nadykto, Alexey B; Yu, Fangqun; Herb, J; Wang, Wei

    2010-01-14

    Atmospheric aerosols formed via nucleation in the Earth's atmosphere play an important role in the aerosol radiative forcing associated directly with global climate changes and public health. Although it is well-known that atmospheric aerosol particles contain organic species, the chemical nature of and physicochemical processes behind atmospheric nucleation involving organic species remain unclear. In the present work, the interaction of common organic acids with molecular weights of 122, 116, 134, 88, 136, and 150 (benzoic, maleic, malic, pyruvic, phenylacetic, and tartaric acids) with nucleation precursors and charged trace species has been investigated. We found a moderate strong effect of the organic species on the stability of neutral and charged ionic species. In most cases, the free energies of the mixed H(2)SO(4)-organic acid dimer formation are within 1-1.5 kcal mol(-1) of the (H(2)SO(4))(NH(3)) formation energy. The interaction of the organic acids with trace ionic species is quite strong, and the corresponding free energies far exceed those of the (H(3)O(+))(H(2)SO(4)) and (H(3)O(+))(H(2)SO(4))(2) formation. These considerations lead us to conclude that the aforementioned organic acids may possess a substantial capability of stabilizing both neutral and positively charged prenucleation clusters, and thus, they should be studied further with regard to their involvement in the gas-to-particle conversion in the Earth's atmosphere.

  17. The Influence of Urban Emissions on Background Aerosols and Trace Gases in Amazonia as Seen in the GoAmazon2014/2015 Experiment.

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Martin, S. T.; Barbosa, H. M.; Brito, J.; Carbone, S.; Rizzo, L. V.; Andreae, M. O.; Pöhlker, C.; Souza, R. A. F. D.

    2015-12-01

    presented together with air mass trajectories following the evolution of aerosol and trace gases in GoAmazon2014. Research funded by INCT Global Change, CNPq and FAPESP.

  18. Agricultural fires in the southeastern U.S. during SEAC4RS: Emissions of trace gases and particles and evolution of ozone, reactive nitrogen, and organic aerosol

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoxi; Zhang, Y.; Huey, L. G.; Yokelson, R. J.; Wang, Y.; Jimenez, J. L.; Campuzano-Jost, P.; Beyersdorf, A. J.; Blake, D. R.; Choi, Y.; St. Clair, J. M.; Crounse, J. D.; Day, D. A.; Diskin, G. S.; Fried, A.; Hall, S. R.; Hanisco, T. F.; King, L. E.; Meinardi, S.; Mikoviny, T.; Palm, B. B.; Peischl, J.; Perring, A. E.; Pollack, I. B.; Ryerson, T. B.; Sachse, G.; Schwarz, J. P.; Simpson, I. J.; Tanner, D. J.; Thornhill, K. L.; Ullmann, K.; Weber, R. J.; Wennberg, P. O.; Wisthaler, A.; Wolfe, G. M.; Ziemba, L. D.

    2016-06-01

    Emissions from 15 agricultural fires in the southeastern U.S. were measured from the NASA DC-8 research aircraft during the summer 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. This study reports a detailed set of emission factors (EFs) for 25 trace gases and 6 fine particle species. The chemical evolution of the primary emissions in seven plumes was examined in detail for ~1.2 h. A Lagrangian plume cross-section model was used to simulate the evolution of ozone (O3), reactive nitrogen species, and organic aerosol (OA). Observed EFs are generally consistent with previous measurements of crop residue burning, but the fires studied here emitted high amounts of SO2 and fine particles, especially primary OA and chloride. Filter-based measurements of aerosol light absorption implied that brown carbon (BrC) was ubiquitous in the plumes. In aged plumes, rapid production of O3, peroxyacetyl nitrate (PAN), and nitrate was observed with ΔO3/ΔCO, ΔPAN/ΔNOy, and Δnitrate/ΔNOy reaching ~0.1, ~0.3, and ~0.3. For five selected cases, the model reasonably simulated O3 formation but underestimated PAN formation. No significant evolution of OA mass or BrC absorption was observed. However, a consistent increase in oxygen-to-carbon (O/C) ratios of OA indicated that OA oxidation in the agricultural fire plumes was much faster than in urban and forest fire plumes. Finally, total annual SO2, NOx, and CO emissions from agricultural fires in Arkansas, Louisiana, Mississippi, and Missouri were estimated (within a factor of ~2) to be equivalent to ~2% SO2 from coal combustion and ~1% NOx and ~9% CO from mobile sources.

  19. Characteristics of trace gases and aerosols at top of urban canopy layer in Nanjing of China from one year observational study

    NASA Astrophysics Data System (ADS)

    Wang, Tijian

    2013-04-01

    To understand the physical and chemical processes of air pollution formation in urban and their linkage with climate change in Yangtze River Delta(YRD), the fast developing area in China, a monitoring site was built on the top of a high building in the center of Nanjing. The site was set up to investigate the long term variations of trace gases and aerosols, which may play important roles in air pollution and climate change in regional scale. From one year measurement records, the annual average concentrations of ozone, sulfur dioxide, carbon monoxide, carbon dioxide, nitric oxide, total reactive nitrogen, water vapor are reported as 161.9±19.4 ppb, 93.8±8.9 ppb, 3856.7±412.1 ppb, 565.1±20.0 ppm, 173.6±15.6 ppb, 230.8±24.9 ppb, 34.76±7.2x10-3, respectively. PM10, PM2.5, visibility, black carbon, back scattering of particles(BSP), single scattering albedo(SSA), aerosol optical depth(AOD) and Angstrom wavelength exponent (AWE) are 115±113.1 μg/m3, 54±46.1 μg/m3, 9780±5594 m, 3055.9±2102.3 ng/m3, 66.3±97.5 Mm-1, 0.5±2.4, 0.7±0.38 and 1.22±0.28, respectively. Measurement show that the levels of air pollutants in YRD in East China are high compared to Pearl River Delta(PRD) in South China and Jing-Jin-Ji (JJJ) in North China, suggesting a possible stronger effect on atmospheric environment, climate change and human health in this region, which should be further addressed in the future study.

  20. Modeling soil climate controls on the exchange of trace gases between the terrestrial biosphere and the atmosphere. Ph.D. Thesis

    SciTech Connect

    Frolking, S.E.

    1993-12-31

    Soil temperature and moisture profiles (soil climate) have a strong influence on the rate of trace gas exchange between the terrestrial biosphere and the atmosphere through the controls exerted on microbial processes and the physical exchange of gases. Principal controls of biological denitrification in mineral soils are the availability of carbon and nitrogen substrates and the soil anaerobic status. A process-oriented model of decomposition and denitrification in soils (DNDC) was modified to have a more detailed portrayal of these controls. In particular, a diffusive soil gas phase was added, along with a method for determining anaerobic and aerobic fractional volume within a soil profile. The model generally overestimated N2O fluxes when compared to field data from a sandy soil in Costa Rica, but captured the timing and shape of the brief flux episodes. Several modelling shortcomings are discussed, including the nature of the carbon substrates and the nature and dynamics of soil anaerobic fractional volume. Methane flux from wetland soils is generally correlated with soil temperature and depth to water table. A model of peat soil climate was developed and applied to a small, poor fen in southern New Hampshire. Temperature profiles and ice depth are in good agreement with field data, but depth to water table is more problematic. Field-based flux correlations to soil temperature, depth to water table, and weighted recent precipitation were developed. When used with the wetland soil climate model, much of the seasonal and shorter period flux variability was captured. The model was then driven by local weather data for 1926-1986; flux variability was dependent on both summer season temperatures and summer precipitation patterns. It is estimated that a five-year field study would capture most of the inter-annual variability.

  1. A study for development of emission factors for trace gases and carbonaceous particulate species from in situ burning of wheat straw in agricultural fields in india

    NASA Astrophysics Data System (ADS)

    Sahai, Shivraj; Sharma, C.; Singh, D. P.; Dixit, C. K.; Singh, Nahar; Sharma, P.; Singh, K.; Bhatt, S.; Ghude, S.; Gupta, V.; Gupta, Raj K.; Tiwari, M. K.; Garg, S. C.; Mitra, A. P.; Gupta, Prabhat K.

    Major crops subject to field burning of crop residue (FBCR) generated an estimated 284 Tg of residue in India, of which 40% was contributed by wheat in the year 2000. About 7.5% of this total generated wheat straw was subjected to on-site burning, that is expected to emit large amounts of trace gases and particulate matter (PM) to the atmosphere, whose country-specific estimates and emission factors (EFs) are presently not available. An in situ experiment for wheat straw burning was undertaken for developing India specific EFs. The EFs of CO2, CH4, CO, N2O, NOx, NO and NO2 were found to be 1787±36, 3.6±2.7, 28.1±20.1, 0.74±0.46, 1.70±1.68, 0.78±0.71 and 0.56±0.47gkg-1, whereas those for organic carbon (OC), black carbon (BC) and total carbon (TC) were 0.3±0.1, 0.2±0.1, and 0.5±0.2gkg-1, respectively. Although these EFs have been generated from a single field experiment nevertheless they address important information gap on FBCR in the region. Further, the total emissions of CH4, CO2, CO, N2O, NOx, NO, NO2, OC, BC and TC from wheat straw burning in India for the year 2000 was estimated as 68±51, 34435±682, 541±387, 14±9, 33±32, 15±14, 11±9, 6±2, 3±1 and 10±4 Gg, respectively.

  2. Continental pollution in the western Mediterranean basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-08-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the western Mediterranean basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summer 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m above sea level over an extended area (40-45° N and 2° W-12° E) including the Gulf of Genoa, southern France, the Gulf of Lion, and the Spanish coast. During TRAQA and SAFMED the study area experienced a wide range of meteorological conditions which favoured pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study show that continental pollution largely affects the western Mediterranean both close to coastal regions and in the open sea as far as ~ 250 km from the coastline. The measured aerosol scattering coefficient varies between ~ 20 and 120 Mm-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-165 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ~ 30 and 5000-6000 scm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental areas under pollution conditions. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 scm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new particle formation (NPF) episodes over the basin.

  3. Application of the LIRIC algorithm for the characterization of aerosols during the Airborne Romanian Measurements of Aerosols and Trace gases (AROMAT) campaign

    NASA Astrophysics Data System (ADS)

    Stefanie, Horatiu; Nicolae, Doina; Nemuc, Anca; Belegante, Livio; Toanca, Florica; Ajtai, Nicolae; Ozunu, Alexandru

    2015-04-01

    The ESA/ESTEC AROMAT campaign (Airborne Romanian Measurements of Aerosols and Trace gases) was held between 1st and 14th of September 2014 with the purpose to test and inter-compare newly developed airborne and ground-based instruments dedicated to air quality studies in the context of validation programs of the forthcoming European Space Agency satellites (Sentinel 5P, ADM-Aeolus and EarthCARE). Ground-based remote sensing and airborne in situ measurements were made in southern Romania in order to assess the level and the variability of NO2 and particulate matter, focusing on two areas of interest: SW (Turceni), where many coal based power plants are operating, and SE (Bucharest), affected by intense traffic and partially by industrial pollution. In this paper we present the results obtained after the application of the Lidar - Radiometer Inversion Code (LIRIC) algorithm on combined lidar and sunphotometer data collected at Magurele, 6 km South Bucharest. Full lidar data sets in terms of backscatter signals at 355, 532 and 1064 nm, as well as depolarization at 532 nm were used and combined with Aerosol Robotic Network (AERONET) data, in order to retrieve the profiles of aerosol volume concentrations, separated as fine, spherical and spheroidal coarse modes. Preliminary results showed that aerosols generated by traffic and industrial activities were present in the Planetary Boundary Layer, while biomass burning aerosols transported from the Balkan Peninsula were detected in the upper layers. Acknowledgements: ***This work has been supported by Programme for Research- Space Technology and Advanced Research - STAR, project number 55/2013 - CARESSE. ***The financial support by the European Community's FP7 - PEOPLE 2011 under ITaRS Grant Agreement n° 289923 is gratefully acknowledged.

  4. Atmospheric pollutants and trace gases

    SciTech Connect

    Ranieri, A.; Schenone, G.; Lencioni, L.; Soldatini, G.F.

    1994-03-01

    Pumpkin [Cucurbita pepo (L.) cv. Ambassador] plants were grown under either nonfiltered or filtered ambient air in open-top field chambers (OTCs) near the urban area of Milan, Northern Italy. The effects of ambient air pollution on the enzymatic detoxfication system of the leaves, both in terms of activity and isoform pattern were investigated. The data on air quality showed that ozone was the main phytotoxic pollutant present in ambient air, reaching a 7 h mean of 63 nL L{sup -1} and a maximum hourly peak of 104 nL L{sup -1} The peroxidase and catalase activities increased fourfold and twofold, respectively in the nonfiltered air plants In comparison to the filtered air ones. The peroxidase patterns were very modified in the polluted plants. In contrast no significant changes were found in the activity and isoenzyme pattern of superoxide dismutase. The data reported here suggest that in field-grown pumpkin plants exposed to ambient levels of photooxidants, a stimulation of the peroxddase-catalase detoxification system takes place. 32 refs., 3 figs., 3 tabs.

  5. Procedures for safe handling of off-gases from electric vehicle lead-acid batteries during overcharge

    SciTech Connect

    LaBelle, S.J.; Bhattacharyya, M.H.; Loutfy, R.O.; Varma, R.

    1980-01-25

    The potential for generation of toxic gases from lead-acid batteries has long been recognized. Prior to the current interest in electric vehicles, there were no studies specificaly oriented to toxic gas release from traction batteries, however. As the Department of Energy Demonstration Project (in the Electric and Hybrid Vehicle Program) progresses, available data from past studies and parallel health effects programs must be digested into guidance to the drivers and maintenance personnel, tailored to their contact with electric vehicles. The basic aspects of lead-acid battery operation, vehicle use, and health effects of stibine and arsine to provide electric vehicle users with the information behind the judgment that vehicle operation and testing may proceed are presented. Specifically, it is concluded that stibine generation or arsine generation at rapid enough rates to induce acute toxic response is not at all likely. Procedures to guard against low-level exposure until more definitive data on ambient concentrations of the gases are collected are presented for both charging the batteries and driving the vehicles. A research plan to collect additional quantitative data from electric traction batteries is presented.

  6. Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere

    NASA Astrophysics Data System (ADS)

    Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

    2015-10-01

    Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes in physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased, the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces adsorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the Arctic atmosphere, which need to be incorporated into atmospheric chemical models in the Arctic troposphere.

  7. TRACE ANALYSIS OF FLUORESCEIN-DERIVATIZED PHENOXY ACID HERBICIDES BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY WITH LASER-INDUCTED FLUORESCENCE DETECTION

    EPA Science Inventory

    Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection was used for the trace analysis of phenoxy acid herbicides. Capillary electrophoresis (CE) with LIF detection, which has not previously been used for pesticide analysis, overcomes the po...

  8. Measurements of reactive trace gases and variable O3 formation rates in some South Carolina biomass burning plumes

    SciTech Connect

    Akagi, S. K.; Yokelson, R. J.; Burling, I. R.; Meinardi, S.; Simpson, I.; Blake, D. R.; McMeeking, G. R.; Sullivan, A.; Lee, T.; Kreidenweis, S.; Urbanski, S.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Weise, D. R.

    2013-02-01

    In October-November 2011 we measured the trace gas emission factors from 7 prescribed fires in South Carolina, U.S. using two Fourier transform infrared spectrometer (FTIR) systems and whole air sampling (WAS) into canisters followed by gas-chromatographic analyses. The fires were intended to emulate high-intensity burns as they were lit during the dry season and in most cases represented stands that had not been treated with prescribed burns in 10+ years, if at all. A total of 97 trace gas species are reported here from both airborne and ground-based platforms making this one of the most detailed field studies of fire emissions to date. The measurements included the first data for a suite of monoterpene compounds emitted via distillation of plant tissues during real fires. The known chemistry of the monoterpenes and their measured abundance of ~0.40% of CO (molar basis), ~3.9% of NMOC (molar basis), and ~21% of organic aerosol (mass basis), suggests that they impacted post-emission formation of ozone, aerosol, and small organic trace gases such as methanol and formaldehyde in the sampled plumes. The variability in the terpene emissions in South Carolina (SC) fire plumes was high and, in general, the speciation of the emitted gas-phase non-methane organic compounds was surprisingly different from that observed in a similar study in nominally similar pine forests in North Carolina ~20 months earlier. It is likely that the slightly different ecosystems, time of year and the precursor variability all contributed to the variability in plume chemistry observed in this study and in the literature. The ΔHCN/ΔCO emission ratio, however, is fairly consistent at 0.9 ± 0.06 % for airborne fire measurements in coniferous-dominated ecosystems further confirming the value of HCN as a good biomass burning indicator/tracer. The SC results also support an earlier finding that C3-C4 alkynes may be of use as biomass burning indicators on the time-scale of

  9. Community Radiative Transfer Model Applications - A Study of the Retrieval of Trace Gases in the Atmosphere from Cross-track Infrared Sounder (CrIS) Data of a Full-spectral Resolution

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Nalli, N. R.; Tan, C.; Zhang, K.; Iturbide, F.; Wilson, M.; Zhou, L.

    2015-12-01

    The Community Radiative Transfer Model (CRTM) [3] operationally supports satellite radiance assimilation for weather forecasting, sensor data verification, and the retrievals of satellite products. The CRTM has been applied to UV and visible sensors, infrared and microwave sensors. The paper will demonstrate the applications of the CRTM, in particular radiative transfer in the retrieva algorithm. The NOAA Unique CrIS/ATMS Processing System (NUCAPS) operationally generates vertical profiles of atmospheric temperature (AVTP) and moisture (AVMP) from Suomi NPP Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) measurements. Current operational CrIS data have reduced spectral resolution: 1.25 cm-1 for a middle wave band and 2.5 cm-1 for a short-wave wave band [1]. The reduced spectral data largely degraded the retrieval accuracy of trace gases. CrIS full spectral data are also available now which have single spectral resolution of 0.625 cm-1 for all of the three bands: long-wave band, middle wave band, and short-wave band. The CrIS full-spectral resolution data is critical to the retrieval of trace gases such as O3, CO [2], CO2, and CH4. In this paper, we use the Community Radiative Transfer Model (CRTM) to study the impact of the CrIS spectral resolution on the retrieval accuracy of trace gases. The newly released CRTM version 2.2.1 can simulates Hamming-apodized CrIS radiance of a full-spectral resolution. We developed a small utility that can convert the CRTM simulated radiance to un-apodized radiance. The latter has better spectral information which can be helpful to the retrievals of the trace gases. The retrievals will be validated using both NWP model data as well as the data collected during AEROSE expeditions [4]. We will also discuss the sensitivity on trace gases between apodized and un-apodized radiances. References[1] Gambacorta, A., et al.(2013), IEEE Lett., 11(9), doi:10.1109/LGRS.2014.230364, 1639-1643. [2] Han, Y., et

  10. Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

    NASA Astrophysics Data System (ADS)

    Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

    2015-06-01

    Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C14N- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C14N- line scans further show that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces determines their hygroscopic and optical properties. These abundant SSA, whose reactive surfaces absorb inorganic and organic acidic gases in the arctic troposphere, need to be incorporated into atmospheric chemical models.

  11. Preliminary simulations of planned experiments to study the impact of trace gases on the capacity of the Weyburn-Midale field to store carbon dioxide

    SciTech Connect

    Carroll, S; Hao, Y

    2009-11-13

    The CO{sub 2} stream injecting into the Weyburn-Midale field can be generally classified as a reducing stream with residual H{sub 2}S and low-molecular weight hydrocarbons. The composition of the CO{sub 2} gas stream from the Dakota Gasification Company is reported to be 95% CO{sub 2}, 4% hydrocarbons, and 1% H{sub 2}S by volume (Huxley 2006). In addition to the H{sub 2}S introduced at the injection wells, significant concentrations of H{sub 2}S are thought to have been produced in-situ by sulfate reducing bacteria from previous water floods for enhanced oil production. Produced gas compositions range in H{sub 2}S concentrations from 1 to 6 volume percent. The produced gas, including the trace impurities, is re-injected into the field. Although there is no evidence for inorganic reduction of SO{sub 4}{sup 2-} to H{sub 2}S at the Weyburn-Midale field, Sitchler and Kazuba (2009) suggest that SO{sub 4}{sup 2-} can be inorganically reduced to elemental sulfur in highly reducing environments based on a natural analog study of the Madison Formation in Wyoming. They propose that elevated concentrations of CO{sub 2} dissolve anhydrite to produce the sulfate that is then reduced. Oxidizing CO{sub 2} streams with residual O{sub 2} and SO{sub 2} typical of streams captured from oxyfuel and post combustion processes are not presently an issue at the Weyburn-Midale field. However it is possible that the oxidizing CO{sub 2} streams may be injected in the future in carbonate reservoirs similar to the Weyburn-Midale field. To date there are few modeling and experimental studies that have explored the impact of impurity gases in CO{sub 2} streams targeted for geologic storage (Gale 2009). Jacquemet et al (2009) reviewed select geochemical modeling studies that explored the impact of SO{sub 2} and H{sub 2}S impurities in the waste streams (Gunter et al., 2000, Knauss et al., 2005, Xu et al., 2007). These studies collectively show that SO{sub 2} significantly reduces the pH when

  12. Gas chromatography/trace analysis of derivatized azelaic acid as a stability marker.

    PubMed

    Alzweiri, Muhammed; Tarawneh, Ruba; Khanfar, Mohammad A

    2013-10-01

    Azelaic acid, a naturally occurring saturated dicarboxylic acid, is found in many topical formulations for its various medical benefits or as a byproduct of the oxidative decomposition of unsaturated fatty acids. The poor volatility of azelaic acid hinders its applicability in GC analysis. Therefore, azelaic acid was derivatized by methylation and silylation procedures to enhance its volatility for GC analysis. Accordingly, dimethyl azelate (DMA) and di(trimethylsilyl) azelate were synthesized and characterized by GC-MS. Subsequently, a GC with flame ionization detection method was developed and validated to analyze trace amounts of azelaic acid in some marketed skin creams. Unlike DMA, di(trimethylsilyl) azelate was chemically unstable and degraded within few hours. Nonane was used as a stable internal standard. Variability due to derivatization and extraction was controlled by a standard addition procedure. DMA analysis was linear in a wide concentration range (100 ng/mL to 100 mg/mL). Moreover, the method was accurate (96.4-103.4%) and precise with inter- and intraday variability <2.0% and LOQ and LOD of 100 and 10 ng/mL, respectively. PMID:23893928

  13. Measurements of Atmospheric Trace Gases Over NW Pacific During IOC 2002 Cruise - Pollutants Transported From East Asia and Biogenic Species Emitted From Ocean

    NASA Astrophysics Data System (ADS)

    Kato, S.; Ui, T.; Uematsu, M.; Kajii, Y.

    2002-12-01

    The R/V Melville cruised from Osaka (Japan) on May 1st to Hawaii on Jun 5th, as a project of Intergovernmental Oceanographic Commission (IOC) 2002. During this cruise, atmospheric trace gases (O3, CO, DMS, many hydrocarbons, and halocarbons) were measured. It is expected that polluted air as well as Kosa from east Asia is transported to the Pacific in this season. On the west Pacific near from Japan, the concentrations of anthropogenic species were strongly affected by the meteorological condition. And the hydrocarbon concentrations have not very large difference at the east of Japan (about 145°E) and at 170°E in the same latitude. On 170°E, the ship cruised straight from 50°N to about 20°N, and latitudinal profile of atmospheric species in the Pacific was observed. There are clear concentration decrease from higher latitude to lower latitude for CO, O3, hydrocarbons, and short lived halocarbons. There is a large gap at around 30°N, since maritime air prevail at lower latitude. The ratios of hydrocarbons and CO give some information about their sources. CO and ethane have similar lifetime in the atmosphere, but the ratio ([ethane]/[CO]) decreased drastically as the distance from the land. CO is supplied by the oxidation of CH4 and hydrocarbons also on the ocean, in addition to the transportation of anthropogenically generated CO from land. Therefore concentration decrease of CO is smaller than that of hydrocarbons far from the anthropogenic source area. Biogenically generated species emitted from the ocean (DMS, ethene, propene, isoprene, CH3Br) were also measured during the cruise. Their trends are totally different from anthropogenic hydrocarbons. Higher concentrations of bogenic generated species were observed at lower latitude, where more activated biogenic activity is expected. Similar trend of ethene, propene, and DMS were observed. Especially, ethene and propene have good correlation. Since these species have relatively high reactivity in the

  14. Black carbon and its correlation with trace gases at a rural site in Beijing: Top-down constraints from ambient measurements on bottom-up emissions

    NASA Astrophysics Data System (ADS)

    Wang, Yuxuan; Wang, Xuan; Kondo, Yutaka; Kajino, Mizuo; Munger, J. William; Hao, Jiming

    2011-12-01

    The mass concentrations of black carbon (BC) were measured continuously at Miyun, a rural site near Beijing, concurrently with some trace gases (CO, CO2, NOy, SO2) during the nonheating seasons of 2010 (April to October). The average concentration of BC was 2.26 ± 2.33 μg m-3. About 70%-100% of the air masses arriving at the site from June to September were from the source region of Beijing and the North China Plain (NCP), while in the spring, 40% were of continental background origin. BC had moderate to strong positive correlations with CO (R2 = 0.51), NOy (R2 = 0.58), and CO2 (nonsummer, R2 = 0.54), but not with SO2 (R2 < 0.1). The observed ΔBC/ΔCO ratio was 0.0050 ± 0.0001 μg m-3/ppbv for the regional air masses (excluding the influence of biomass burning). This ratio increased by 68% to 0.0084 ± 0.0004 μg m-3/ppbv after excluding the influence of wet deposition. Accounting further for the impact of atmospheric processes on the observation, we derived an average top-down BC/CO emission ratio of 0.0095 ± 0.002 μg m-3/ppbv for the source region of Beijing and NCP that is 18%-21% lower than the average emission ratio from the bottom-up inventory of Zhang et al. (2009), whereas the difference is substantially lower than the uncertainty of emissions for either species. The difference between the mean bottom-up and top-down emission ratios is most likely to be attributed to the residential sector, which needs to have a lower share in the total emissions of BC or a much lower BC/CO emission ratio. The industry and transportation sectors are found to be dominant sources of BC from Beijing and the NCP rather than from the residential sector as suggested by the bottom-up inventory.

  15. Detections and Sensitive Upper Limits for Methane and Related Trace Gases on Mars during 2003-2014, and planned extensions in 2016

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Villanueva, Geronimo L.; Novak, Robert E.

    2015-11-01

    Five groups report methane detections on Mars; all results suggest local release and high temporal variability [1-7]. Our team searched for CH4 on many dates and seasons and detected it on several dates [1, 9, 10]. TLS (Curiosity rover) reported methane upper limits [6], and then detections [7] that were consistent in size with earlier reports and that also showed rapid modulation of CH4 abundance.[8] argued that absorption features assigned to Mars 12CH4 by [1] might instead be weak lines of terrestrial 13CH4. If not properly removed, terrestrial 13CH4 signatures would appear on the blue wing of terrestrial 12CH4 even when Mars is red-shifted - but they do not (Fig. S6 of [1]), demonstrating that terrestrial signatures were correctly removed. [9] demonstrated that including the dependence of δ13CH4 with altitude did not affect the residual features, nor did taking δ13CH4 as zero. Were δ13CH4 important, its omission would have overemphasized the depth of 13CH4 terrestrial absorption, introducing emission features in the residual spectra [1]. However, the residual features are seen in absorption, establishing their origin as non-terrestrial - [8] now agrees with this view.We later reported results for multiple organic gases (CH4, CH3OH, H2CO, C2H6, C2H2, C2H4), hydroperoxyl (HO2), three nitriles (N2O, NH3, HCN) and two chlorinated species (HCl, CH3Cl) [9]. Most of these species cannot be detected with current space assets, owing to instrumental limitations (e.g., spectral resolving power). However, the high resolution infrared spectrometers (NOMAD, ACS) on ExoMars 2016 (Trace Gas Orbiter) will begin measurements in late 2016. In solar occultation, TGO sensitivities will far exceed prior capabilities.We published detailed hemispheric maps of H2O and HDO on Mars, inferring the size of a lost early ocean [10]. In 2016, we plan to acquire 3-D spatial maps of HDO and H2O with ALMA, and improved maps of organics with iSHELL/NASA-IRTF.References: [1] Mumma et al. Sci09

  16. Continental pollution in the Western Mediterranean Basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-03-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the Western Mediterranean Basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summers 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m a.s.l. over an extended area (40-45° N latitude and 2° W-12° E longitude) including the Gulf of Genoa, Southern France, the Gulf of Lion, and the Spanish coast. TRAQA and SAFMED successfully measured a wide range of meteorological conditions which favoured the pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study indicate that continental pollution largely affects the Western Mediterranean both close to coastal regions and in the open sea as far as ~250 km from the coastline. Aerosol layers not specifically linked with Saharan dust outflows are distributed ubiquitously which indicates quite elevated levels of background pollution throughout the Western Basin. The measured aerosol scattering coefficient varies between ~20 and 120 M m-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-170 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ˜ 100 and 5000-6000 s cm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental urban areas. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 s cm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new

  17. Combining moving inlets for measuring gradients of reactive trace gases and thoron measurements for the determination of near surface fluxes -first results from the Amazon rain forest-

    NASA Astrophysics Data System (ADS)

    Sörgel, Matthias; Artaxo, Paulo; Kesselmeier, Jürgen; Quesada, Carlos Alberto; Ferreira de Souza, Rodrigo Augusto; Trebs, Ivonne; Vega, Oscar; Yañez-Serrano, Ana Maria

    2016-04-01

    For many compounds of interest no fast response sensors for the determination of eddy covariance fluxes are available. Therefore, flux-gradient relationships are used. The most common are the aerodynamic gradient method and the modified Bowen ratio method. For those approaches some assumptions have to be made which restrict their use. An alternative approach to calculate these fluxes might be given by the "thoron clock" method. The radon isotope Thoron (220Rn) is exhaled from the soil and has a half life time of 56 seconds. Therefore, it exists in measureable amounts only close to the ground and is hardly advected. Its only source is the radioactive decay of Thorium in soil. As it is a noble gas Thoron is not influenced by biochemical processes in air. Consequently, its concentration profile only depends on vertical mixing and the radioactive decay which is a physical constant. According to Lehmann et al. (1999) and Plake and Trebs (2013) a transport-time can be directly calculated from two heights thoron concentration/activity for the layer in-between without further assumptions. From this transport time the transfer velocity is derived which is then applied to calculate the fluxes of other (reactive) trace gases. A major advantage of the method is that the transport-time is known and using the measured concentration profile the chemical loss of a compound can be directly calculated and corrected for. We have applied this method for a first time in the Amazon rainforest during a field campaign at the ATTO site 150 km North East of Manaus in the dry season of 2014. We measured gradients of NO, NO2, O3, HONO and VOCs by using a movable inlet on a lift system close to the forest floor (0.19 m, 0.52 m and 1.59 m). A Thoron profile was measure in parallel at the lower two heights. First results of the gradients, the transport times and some preliminary flux values will be presented. References: Lehmann, B.E., Lehmann, M., Neftel, A .: 220 Radon calibration of near

  18. A Pilot-Scale Evaluation of a New Technology to Control NO(x) Emissions from Boilers at KSC: Hydrogen Peroxide Injection into Boiler Flue Gases Followed by Wet Scrubbing of Acid Gases

    NASA Technical Reports Server (NTRS)

    Cooper, C. David

    1997-01-01

    Emissions of nitrogen oxides NO(x) are a significant problem in the United States. NO(x) are formed in any combustion process, therefore it is not surprising that NO(x) are emitted from the boilers at KSC. Research at UCF has shown (in the laboratory) that injecting H2O2 into hot simulated flue gases can oxidize the NO and NO2 to their acid gas forms, HNO2 and HNO3, respectively. These acid gases are much more water soluble than their counterparts, and theoretically can be removed easily by wet scrubbing. This technology was of interest to NASA, both for their boilers at KSC, and for their combustion sources elsewhere. However, it was necessary to field test the technology and to provide pilot-scale data to aid in design of full-scale facilities. Hence this project was initiated in May of 1996.

  19. Microscopic evaluation of trace metals in cloud droplets in an acid precipitation region.

    PubMed

    Li, Weijun; Wang, Yan; Collett, Jeffrey L; Chen, Jianmin; Zhang, Xiaoye; Wang, Zifa; Wang, Wenxing

    2013-05-01

    Mass concentrations of soluble trace metals and size, number, and mixing properties of nanometal particles in clouds determine their toxicity to ecosystems. Cloud water was found to be acidic, with a pH of 3.52, at Mt. Lu (elevation 1,165 m) in an acid precipitation region in South China. A combination of Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Transmission Electron Microscopy (TEM) for the first time demonstrates that the soluble metal concentrations and solid metal particle number are surprisingly high in acid clouds at Mt. Lu, where daily concentrations of SO2, NO2, and PM10 are 18 μg m(-3), 7 μg m(-3), and 22 μg m(-3). The soluble metals in cloudwater with the highest concentrations were zinc (Zn, 200 μg L(-1)), iron (Fe, 88 μg L(-1)), and lead (Pb, 77 μg L(-1)). TEM reveals that 76% of cloud residues include metal particles that range from 50 nm to 1 μm diameter with a median diameter of 250 nm. Four major metal-associated particle types are Pb-rich (35%), fly ash (27%), Fe-rich (23%), and Zn-rich (15%). Elemental mapping shows that minor soluble metals are distributed within sulfates of cloud residues. Emissions of fine metal particles from large, nonferrous industries and coal-fired power plants with tall stacks were transported upward to this high elevation. Our results suggest that the abundant trace metals in clouds aggravate the impacts of acid clouds or associated precipitation on the ecosystem and human health.

  20. Mineral phases and mobility of trace metals in white aluminum precipitates found in acid mine drainage.

    PubMed

    Kim, Yeongkyoo

    2015-01-01

    The white aluminum precipitates (S1,S2,S4-1,S4-2) collected at three different locations affected by acid mine and rock drainage were studied to characterize the mineral phases and mobility of trace metals. Chemical analysis, XRD, SEM, NMR, and sequential extraction method were mainly used. XRD data showed that most white aluminum precipitates are amorphous with small amount of gypsum, which was also confirmed by SEM. The (27)Al MAS NMR spectra provide more detailed information on the local environments of aluminum in those samples. The samples collected at two locations (S3, and S4-1 and S4-2) contain 4-coordinated aluminum, suggesting that the samples contain a significant amount of amorphous phase from Al13-tridecamer. Chemical data of calcium and sulfur with (27)Al MAS NMR spectra suggest that the relative amounts of amorphous phase from Al13-tridecamer, hydrobasaluminite, aluminum hydroxide, and gypsum are different for each sample. Different amount of amorphous phase from Al13-tridecamer in those samples are probably caused by the different geochemical conditions and hydrolysis by aging in water. Sequential extraction results show that water soluble fraction and sorbed and exchangeable fraction of trace metals in sample collected as suspended particles (S1) are higher than other samples, and can affect the ecological system in waters by releasing aluminum and trace metals. These results suggest that careful characterization of white aluminum precipitates is needed to estimate the environmental effects of those precipitates in acid mine drainage. PMID:25213794

  1. Treatment of acid mine drainage with fly ash: Removal of major contaminants and trace elements

    SciTech Connect

    Gitari, M.W.; Petrik, L.F.; Etchebers, O.; Key, D.L.; Iwuoha, E.; Okujeni, C.

    2006-08-15

    Acid mine drainage (AMD) has been reacted with two South African fly ashes in a batch setup in an attempt to evaluate their neutralization and major, trace elements removal capacity. Different fly ash:acid mine drainage ratios (FA:AMD) were stirred in a beaker for a set time and the process water analyzed for major, trace elements and sulphate content. The three factors that finally dictated the nature of the final solution in these neutralization reactions were the FA:AMD ratio, the contact time of the reaction and the chemistry of the AMD. Efficiency of the elements removal was directly linked to the amount of FA in the reaction mixture and to the final pH attained. Most elements attained approximate to 100% removal only when the pH of minimum solubility of their hydroxides was achieved (i.e., Mg = 10.49 - 11.0, Cu{sup 2+} = 6, Pb{sup 2+} = 6 - 7). Dissolution of CaO and subsequent precipitation of gypsum and formation of Al, Fe oxyhydroxysulphates, Fe oxyhydroxides with subsequent adsorption of sulphate contributed to the sulphate attenuation. Significant leaching of B, Sr, Ba and Mo was observed as the reaction progressed and was observed to increase with quantity of fly ash in the reaction mixture. However B was observed to decrease at high FA:AMD ratios probably as result of co-precipitation with CaCO{sub 3}(s).

  2. Interaction of trace elements in acid mine drainage solution with humic acid.

    PubMed

    Suteerapataranon, Siripat; Bouby, Muriel; Geckeis, Horst; Fanghänel, Thomas; Grudpan, Kate

    2006-06-01

    The release of metal ions from a coal mining tailing area, Lamphun, Northern Thailand, is studied by leaching tests. Considerable amounts of Mn, Fe, Al, Ni and Co are dissolved in both simulated rain water (pH 4) and 10 mg L(-1) humic acid (HA) solution (Aldrich humic acid, pH 7). Due to the presence of oxidizing pyrite and sulfide minerals, the pH in both leachates decreases down to approximately 3 combined with high sulfate concentrations typical to acid mine drainage (AMD) water composition. Interaction of the acidic leachates upon mixing with ground- and surface water containing natural organic matter is simulated by subsequent dilution (1:100; 1:200; 1:300; 1:500) with a 10 mg L(-1) HA solution (ionic strength: 10(-3) mol L(-1)). Combining asymmetric flow field-flow fractionation (AsFlFFF) with UV/Vis and ICP-MS detection allows for the investigation of metal ion interaction with HA colloid and colloid size evolution. Formation of colloid aggregates is observed by filtration and AsFlFFF depending on the degree of the dilution. While the average HA size is initially found to be 2 nm, metal-HA complexes are always found to be larger. Such observation is attributed to a metal induced HA agglomeration, which is found even at low coverage of HA functional groups with metal ions. Increasing the metal ion to HA ratio, the HA bound metal ions and the HA entities are growing in size from <3 to >450 nm. At high metal ion to HA ratios, precipitation of FeOOH phases and HA agglomeration due to colloid charge neutralization by complete saturation of HA complexing sites are responsible for the fact that most of Fe and Al precipitate and are found in a size fraction >450 nm. In the more diluted solutions, HA is more relevant as a carrier for metal ion mobilization.

  3. Field measurement of acid gases and soluble anions in atmospheric particulate matter using a parallel plate wet denuder and an alternating filter-based automated analysis system.

    PubMed

    Boring, C Bradley; Al-Horr, Rida; Genfa, Zhang; Dasgupta, Pumendu K; Martin, Michael W; Smith, William F

    2002-03-15

    We present a new fully automated instrument for the measurement of acid gases and soluble anionic constituents of atmospheric particulate matter. The instrument operates in two independent parallel channels. In one channel, a wet denuder collects soluble acid gases; these are analyzed by anion chromatography (IC). In a second channel, a cyclone removes large particles and the aerosol stream is then processed by another wet denuder to remove potentially interfering gases. The particles are then collected by one of two glass fiber filters which are alternately sampled, washed, and dried. The washings are preconcentrated and analyzed by IC. Detection limits of low to subnanogram per cubic meter concentrations of most gaseous and particulate constituents can be readily attained. The instrument has been extensively field-tested; some field data are presented. Results of attempts to decipher the total anionic constitution of urban ambient aerosol by IC-MS analysis are also presented.

  4. Dissolved, particulate and acid-leachable trace metal concentrations in North Atlantic precipitation collected on the Global Change Expedition

    SciTech Connect

    Lim, B.; Jickells, T.D. )

    1990-12-01

    Atmospheric inputs of trace metals into surface waters are an important pathway for the oceanic biogeochemical cycling of many trace constituents. Rainwater samples from six precipitation events were collected on board ship during legs 3 and 4 of the Global Change Expedition over the North Atlantic Ocean and analyzed for dissolved, particulate (Al and Pb), and acid-leachable trace metals (Al, Fe, Mn, Cd, Cu, Pb, Zn). Acid-leachable concentrations of the elements were similar to reported values from the North Atlantic and Pacific Oceans which were measured using comparable acidification procedures. Concentrations of dissolved and particulate Al and Pb were determined in rain events acid-leachable and total trace metal concentrations suggest that the acid-leachable fraction of metals can significantly underestimate total concentrations of crustal elements in rain. The solubilities of Al and Pb in precipitation were variable and mean solubilities of the elements were 13% and 45%, respectively. Recycled sea salt components were less than 14% for Al, Fe, Mn, Pb, Cd, Cu, and Zn, indicating that the net trace metal flux is from the atmosphere to the oceans. Deep sea particle fluxes for these metals through the western tropical North Atlantic exceed atmospheric deposition fluxes by a factor of 18 to 41. 57 refs., 2 figs., 12 tabs.

  5. Tracing Carbon Sources through Aquatic and Terrestrial Food Webs Using Amino Acid Stable Isotope Fingerprinting

    PubMed Central

    Larsen, Thomas; Ventura, Marc; Andersen, Nils; O’Brien, Diane M.; Piatkowski, Uwe; McCarthy, Matthew D.

    2013-01-01

    Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ13C patterns among amino acids (δ13CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ13CAA patterns in contrast to bulk δ13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. PMID:24069196

  6. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    PubMed

    Larsen, Thomas; Ventura, Marc; Andersen, Nils; O'Brien, Diane M; Piatkowski, Uwe; McCarthy, Matthew D

    2013-01-01

    Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13)C patterns among amino acids (δ(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13)CAA patterns in contrast to bulk δ(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

  7. In-vivo measurement of intrauterine gases and acid-base values early in human pregnancy.

    PubMed

    Jauniaux, E; Watson, A; Ozturk, O; Quick, D; Burton, G

    1999-11-01

    A new multiparameter sensor that combines electrochemical and fibre-optic technology was used for continuous in-vivo investigation of pH, carbon dioxide partial pressure (PCO(2)), oxygen partial pressure (PO(2)), bicarbonate concentration (HCO(3)(-)), base excess, and oxygen saturation (O(2)Sat) early in human pregnancy. The sensor was inserted into the amniotic cavity and the placental bed of 16 pregnancies at 10-15 weeks gestation, before termination under general anaesthesia. Amniotic fluid and retroplacental blood from the same site were also aspirated and analysed by means of cartridges and a portable blood gas analyser. Eleven series of measurements were obtained. The variation in measurements over the 5 min of monitoring was acid-base with a sensor is stable and accurate. Such technology will be helpful in improving our understanding of the fetoplacental metabolism in normal and complicated pregnancies. PMID:10548645

  8. Variations in PM2.5, TSP, BC, and trace gases (NO2, SO2, and O3) between haze and non-haze episodes in winter over Xi'an, China

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Shen, Zhenxing; Cao, Junji; Zhang, Renjian; Zhang, Leiming; Huang, R.-J.; Zheng, Chenjia; Wang, Linqing; Liu, Suixin; Xu, Hongmei; Zheng, Chunli; Liu, Pingping

    2015-07-01

    To investigate chemical profiles and formation mechanisms of aerosol particles in winter haze events, daily PM2.5 and TSP, 5-min BC, and 15-min trace gases (SO2, NO2, and O3) were measured continuously during Dec. 1-31, 2012 in Xi'an. Chemical analysis was also conducted for nine water-soluble inorganic ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, and SO42-), organic carbon (OC), elemental carbon (EC), and eight carbon fractions (OC1, OC2, OC3, OC4, EC1, EC2, EC3, and OP) in both PM2.5 and TSP samples. Higher levels of TSP, PM2.5, BC, SO2, and NO2, and lower levels of O3 were observed during haze periods in comparison with non-haze days. The sum of the major secondary ionic species (NH4+, NO3-, and SO42-) in PM2.5 or TSP during haze periods was about 3 times of that during non-haze days. Ion balance calculations showed that PM2.5 samples were acidic during haze periods and were close to neutral during non-haze days. The mean carbon levels were 52.9 μg m-3 and 82.1 μg m-3 in PM2.5 and TSP, respectively, during haze events, which were ∼1.5 times of those during non-haze days. The diurnal variations of BC during non-haze days showed a bimodal distribution with two peaks coincided with traffic rush hours. This was not the case during haze periods, which exhibited a relatively smooth pattern but with high concentration levels, providing evidence of particle accumulation. The ratios of SO42 - /EC, NO3-/EC, and NH4+/EC sharply increased during haze periods, indicating the important pathway of secondary inorganic species formation through aqueous-phase transformation under high relative humidity condition. This study also highlights that wintertime secondary organic carbon (SOC) formation can be an important contributor to carbonaceous aerosol, especially during haze periods.

  9. Potential effects of clean coal technologies on acid precipitation, greenhouse gases, and solid waste disposal

    SciTech Connect

    Blasing, T.J.; Miller, R.L.; McCold, L.N.

    1993-11-01

    The US Department of Energy`s (DOE`s) Clean Coal Technology Demonstration Program (CCTDP) was initially funded by Congress to demonstrate more efficient, economically feasible, and environmentally acceptable coal technologies. Although the environmental focus at first was on sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) because their relationship to acid precipitation, the CCTDP may also lead to reductions in carbon dioxide (CO{sub 2}) emissions and in the volume of solid waste produced, compared with conventional technologies. The environmental effects of clean coal technologies (CCTs) depend upon which (if any) specific technologies eventually achieve high acceptance in the marketplace. In general, the repowering technologies and a small group of retrofit technologies show the most promise for reducing C0{sub 2} emissions and solid waste. These technologies also compare favorably with other CCTs in terms of SO{sub 2} and NO{sub x} reductions. The upper bound for CO{sup 2} reductions in the year 2010 is only enough to reduce global ``greenhouse`` warming potential by about 1%. However, CO{sub 2} emissions come from such variety of sources around the globe that no single technological innovation or national policy change could realistically be expected to reduce these emissions by more than a few percent. Particular CCTs can lead to either increases or decreases in the amount of solid waste produced. However, even if decreases are not achieved, much of the solid waste from clean coal technologies would be dry and therefore easier to dispose of than scrubber sludge.

  10. Acid dew and the role of chemistry in the dry deposition of reactive gases to wetted surfaces

    NASA Technical Reports Server (NTRS)

    Chameides, William L.

    1987-01-01

    A formalism is developed to describe the dry deposition of soluble reactive gases to wetted surfaces in terms of the relevant meteorological conditions, the surface roughness, the total amount of liquid water present on the surface, the rate of accumulation of this water, and the species' solubility and reactivity in the surface water. This formulation is then incorporated into a model designed to simulate the generation of acidic dew from the deposition of HNO3, SO2, S(IV) oxidants, H2O2, and O3. Similar to the observations of dew in the continental U.S., the model generates a dewdrop pH of about 4 by the end of the night; the pH can rapidly fall to toxic levels due to rapid evaporation after sunrise. Relatively low deposition velocities are predicted for the SO2 and O3 because of their lower solubilities and hence larger surface resistances than those of the other oxidants. Because the chemical lifetime of the SO2 in the dew is influenced by the atmospheric levels of H2O2, O3, and SO2, the SO2 deposition velocity is a strong function of these species' atmospheric abundances.

  11. Effects of anaesthesia on blood gases, acid-base status and ions in the toad Bufo marinus.

    PubMed

    Andersen, Johnnie Bremholm; Wang, Tobias

    2002-03-01

    It is common practice to chronically implant catheters for subsequent blood sampling from conscious and undisturbed animals. This method reduces stress associated with blood sampling, but anaesthesia per se can also be a source of stress in animals. Therefore, it is imperative to evaluate the time required for physiological parameters (e.g. blood gases, acid-base status, plasma ions, heart rate and blood pressure) to stabilise following surgery. Here, we report physiological parameters during and after anaesthesia in the toad Bufo marinus. For anaesthesia, toads were immersed in benzocaine (1 g l(-1)) for 15 min or until the corneal reflex disappeared, and the femoral artery was cannulated. A 1-ml blood sample was taken immediately after surgery and subsequently after 2, 5, 24 and 48 h. Breathing ceased during anaesthesia, which resulted in arterial Po(2) values below 30 mmHg, and respiratory acidosis developed, with arterial Pco(2) levels reaching 19.5+/-2 mmHg and pH 7.64+/-0.04. The animals resumed pulmonary ventilation shortly after the operation, and oxygen levels increased to a constant level within 2 h. Acid--base status, however, did not stabilise until 24 h after anaesthesia. Haematocrit doubled immediately after cannulation (26+/-1%), but reached a constant level of 13% within 24 h. Blood pressure and heart rate were elevated for the first 5 h, but decreased after 24 h to a constant level of approximately 30 cm H2O and 35 beats min(-1), respectively. There were no changes following anaesthesia in mean cellular haemoglobin concentration, [K+], [Cl-], [Na+], [lactate] or osmolarity. Toads fully recovered from anaesthesia after 24 h.

  12. Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): emissions of trace gases and light-absorbing carbon from wood and dung cooking fires, garbage and crop residue burning, brick kilns, and other sources

    NASA Astrophysics Data System (ADS)

    Stockwell, Chelsea E.; Christian, Ted J.; Goetz, J. Douglas; Jayarathne, Thilina; Bhave, Prakash V.; Praveen, Puppala S.; Adhikari, Sagar; Maharjan, Rashmi; DeCarlo, Peter F.; Stone, Elizabeth A.; Saikawa, Eri; Blake, Donald R.; Simpson, Isobel J.; Yokelson, Robert J.; Panday, Arnico K.

    2016-09-01

    The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas chemistry for the emissions from many of the sources. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared (FTIR) spectroscopy, whole-air sampling (WAS), and photoacoustic extinctiometers (PAX; 405 and 870 nm) based on field work with a moveable lab sampling authentic sources. The primary aerosol optical properties reported include emission factors (EFs) for scattering and absorption coefficients (EF Bscat, EF Babs, in m2 kg-1 fuel burned), single scattering albedos (SSAs), and absorption Ångström exponents (AAEs). From these data we estimate black and brown carbon (BC, BrC) emission factors (g kg-1 fuel burned). The trace gas measurements provide EFs (g kg-1) for CO2, CO, CH4, selected non-methane hydrocarbons up to C10, a large suite of oxygenated organic compounds, NH3, HCN, NOx, SO2, HCl, HF, etc. (up to ˜ 80 gases in all). The emissions varied significantly by source, and light absorption by both BrC and BC was important for many sources. The AAE for dung-fuel cooking fires (4.63 ± 0.68) was significantly higher than for wood-fuel cooking fires (3.01 ± 0.10). Dung-fuel cooking fires also emitted high levels of NH3 (3.00 ± 1.33 g kg-1), organic acids (7.66 ± 6.90 g kg-1), and HCN (2.01 ± 1.25 g kg-1), where the latter could

  13. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    EPA Science Inventory

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  14. Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

    PubMed

    Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts.

  15. Trace metals in interstitial waters from sandstones: acidic inputs to shallow groundwaters.

    PubMed

    Edmunds, W M; Kinniburgh, D G; Moss, P D

    1992-01-01

    There is some evidence from southern Britain that shallow groundwaters in non-carbonate lithologies may be affected by acidic deposition. To investigate this, interstitial water profiles down to 12 m have been obtained from unsaturated sands or semi-consolidated sandstones from the Folkestone Beds (Lower Greensand) of Surrey and the Sherwood Sandstone of the West Midlands. The pH of the interstitial waters generally increased with depth and reflected an increase in the base saturation of the exchange complex. Beneath the highly acidic surface soil horizons (pH 3.0-3.5), interstitial waters with a pH of 4.0-4.5 were found down to depths of several metres. The pH progressively increased to around pH 5.5 because of base cation desorption and the weathering of silicate minerals. High concentrations of aluminium (10-20 mg litre(-1)) and other metals (Fe, Mn, Cu, Ni, Co, Zn, Be) were found in the interstitial water in the upper unsaturated zone. Most metal concentrations were strongly pH-dependent but also reflected the geochemical characteristics of the parent sands or sandstones. H+ and trace element concentrations were slightly higher beneath areas of afforestation than beneath heathland. The downward fluxes of solutes have been estimated using rainfall-derived chloride as a non-reactive solute. The profiles retain a record of 10-20 years input allowing the past inputs from SO4 and other species to be estimated using solute/chloride ratios. Cation exchange sites are probably depleted over a period of decades and there can be a significant decrease in the unsaturated zone pH as a result of increased or sustained acidic deposition. The shallow groundwater environment (0-15 m) in non-carbonate terrains is therefore a sensitive environment where high metal concentrations may be generated and may ultimately lead to water quality problems in shallow water supplies.

  16. Comparison of ground-based FTIR measurements and EMAC model simulations of trace-gases columns near St. Petersburg (Russia) in 2009-2013

    NASA Astrophysics Data System (ADS)

    Virolainen, Yana; Makarova, Maria; Ionov, Dmitry; Polyakov, Alexander; Kirner, Oliver; Timofeyev, Yury; Poberovsky, Anatoly; Imhasin, Hamud

    2014-05-01

    The comparison of simulated atmospheric gases abundances with various experimental data is the very important stage of the numerical models validation and improvement process. In this study, we compare and discuss the observational data obtained from ground-based direct solar absorption measurements of high spectral-resolution FTIR spectrometer Bruker 125 HR operated at the Peterhof station (59.82 N, 29.88 E) with the 3-dimensional model EMAC (ECHAM5/MESSy Atmospheric Chemistry) calculations. The FTIR spectrometer has a maximum optical path difference of 180 cm, yielding a spectral resolution of unapodized spectra up to 0.005 cm-1. Two detectors, MCT (Mercury-Cadmium-Telluride) and InSb (Indium-Antimonide), cover the spectral range of 650-5400 cm-1 that includes many distinct and overlapping absorption lines, and allow the retrieval of a large number of atmospheric constituents. We applied two inversion codes using within NDACC infrared community: SFIT2 and PROFFIT for the retrieval of atmospheric gases column amounts from FTIR recorded spectra. The EMAC model is a numerical chemistry and climate simulation system that includes sub-models describing troposphere and middle atmosphere processes and their interaction with oceans, land and human influences. The simulation includes a comprehensive atmospheric chemistry setup for the troposphere, the stratosphere and the lower mesosphere. We applied the EMAC (ECHAM5 version 5.3.01, MESSy version 1.10) in the T42L39MA-resolution, i.e. with a spherical truncation of T42 (corresponding to a quadratic Gaussian grid of approximately 2.8 by 2.8 degrees in latitude and longitude) with 39 vertical hybrid pressure levels up to 0.01 hPa. The model simulation allows the comparison of the tropospheric gases (H2O, CO, CH4, and N2O) as well as the stratospheric gases (HCl, HNO3, NO2, O3 and ClONO2) that have been being continuously retrieved at the Peterhof station since 2009. In the study, we analyze the daily and monthly means of

  17. Simultaneous removal of SO2 and trace As2O3 from flue gas: mechanism, kinetics study, and effect of main gases on arsenic capture.

    PubMed

    Li, Yuzhong; Tong, Huiling; Zhuo, Yuqun; Li, Yan; Xu, Xuchang

    2007-04-15

    Sulfur dioxide (SO2) and trace elements are pollutants derived from coal combustion. This study focuses on the simultaneous removal of S02 and trace arsenic oxide (As2O3) from flue gas by calcium oxide (CaO) adsorption in the moderate temperature range. Experiments have been performed on a thermogravimetric analyzer (TGA). The interaction mechanism between As2O3 and CaO is studied via XRD detection. Calcium arsenate [Ca3(AsO4)2] is found to be the reaction product in the range of 600-1000 degrees C. The ability of CaO to absorb As2O3 increases with the increasing temperature over the range of 400-1000 degrees C. Through kinetics analysis, it has been found that the rate constant of arsenate reaction is much higher than that of sulfate reaction. SO2 presence does not affect the trace arsenic capture either in the initial reaction stage when CaO conversion is relatively low or in the later stage when CaO conversion is very high. The product of sulfate reaction, CaS04, is proven to be able to absorb As2O3. The coexisting CO2 does not weaken the trace arsenic capture either.

  18. Nitric acid depressions in and near midlatitude cirrus clouds during TRACE-P

    NASA Astrophysics Data System (ADS)

    Zondlo, M. A.; Cantrell, C. A.; Clarke, A.; Kosciuch, E.; Mauldin, R. L.; Eisele, F. L.

    2003-12-01

    Cirrus cloud ice particles have been implicated in scavenging a wide variety soluble and semisoluble species. Species removed by an ice surface can undergo a number of significant processes including heterogeneous reactions with other adsorbed species, vertical redistribution in the troposphere from sedimenting particles, or modifying the microphysical properties of the ice particle. Nitric acid (HNO3) has been shown in the laboratory to readily adsorb onto ice surfaces, and modeling studies suggest significant perturbations to its distribution can result. Unfortunately, field observations of HNO3 within and near cirrus clouds have shown mixed and sometimes contradictory results. The NASA P-3B aircraft sampled numerous upper tropospheric, mid-latitude ice clouds during Flight 24 of the NASA TRACE-P field experiment. In contrast to tropical cirrus clouds, the cirrus ice clouds sampled by the P-3B were at warmer temperatures of -17 to -32 degrees Celsius and at pressures of 365-436 mb. The clouds' origins ranged from jet stream induced cirrostratus clouds to convectively-induced cirrus anvils. Nitric acid levels decreased 60-70 pptv (35-60%) within the clouds compared to areas just outside of it. Slight asymmetries in the HNO3 profiles around the cloud were noted, with the lee or downwind sides of clouds containing more gradual returns from inside cloud levels to "background" levels, potentially due to greater mixing as the cloud evaporated. If HNO3 removed inside the cloud were distributed evenly onto ice surfaces, approximately one tenth of a monolayer of HNO3 was adsorbed onto ice (based on estimates of ice surface area density of 5000 microns squared per cubic centimeter). The incorporation of HNO3 into existing liquid quaternary NH3/H2SO4/HNO3/H2O aerosols within the cloud could also be important due to the sampling location over central North America where elevated NH3 emissions exist. The midlatitude HNO3/cirrus cases observed on the P-3B will be contrasted to

  19. Electronegative gases

    SciTech Connect

    Christophorou, L.G.

    1981-01-01

    Recent knowledge on electronegative gases essential for the effective control of the number densities of free electrons in electrically stressed gases is highlighted. This knowledge aided the discovery of new gas dielectrics and the tailoring of gas dielectric mixtures. The role of electron attachment in the choice of unitary gas dielectrics or electronegative components in dielectric gas mixtures, and the role of electron scattering at low energies in the choice of buffer gases for such mixtures is outlined.

  20. Direct chiral resolution of metalaxyl and metabolite metalaxyl acid in aged mobile phases: the role of trace water.

    PubMed

    Zhang, Xiaoxiang; Xia, Tingting; Chen, Jingwen; Huang, Liping; Cai, Xiyun

    2010-04-28

    The separation of chiral transformation products greatly complements the understanding of the stereochemistry of chiral pollutants. In this study, direct enantiomeric resolution of metalaxyl and its main degradation product metalaxyl acid, often co-occurring in the environment, was carried out in normal-phase high-performance liquid chromatography with a Chiralcel OJ-H column. (R)-Metalaxyl acid and (S)-metalaxyl, which were almost parallel bonding to the chiral stationary phase, tended to separate, started to overlap, coeluted, and separated again with subtle changes of the mobile phase consisting of n-hexane, 2-propanol, acetic acid, and trace water. Their competition above hampered an acceptable direct separation in fresh mobile phases. Aged mobile phases with a storage period of 3-5 days, however, significantly improved their separation, in which trace water from moisture air diffusion was found to play a major role. Trace water differentially affected peak width and retention times and then induced enhanced peak separation, confirmed by deliberate addition of water to fresh mobile phases. Furthermore, none of the studied factors, involving temperature, concomitant analytes, and trace water, could cause changes of the configuration of the chiral stationary phase. Simultaneous enantiomeric separation of both compounds was achieved in aged or fresh mobile phases with adventitious or added water and gave satisfactory peak separation, all with Rs values of more than 1.20 in environmental samples.

  1. Parameterization of the absorption of the H2O continuum, CO2, O2, and other trace gases in the Fu-Liou solar radiation program

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Zeng, Qingcun; Gu, Y.; Liou, K. N.

    2005-07-01

    The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500 14500 cm-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850 5250 cm-1 are taken as a new single-mixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H2O line and continuum in the 2500 14500 cm-1solar spectral region, ˜1% for H2O (line)+H2O (continuum)+CO2+CH4 in the spectral region 2850 5250 cm-1,and ˜1.5% for H2O (line)+H2O (continuum)+O2 in the 7700 14500 cm-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9% 13% (˜12 W m-2) among which the H2O continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6 9 W m-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar

  2. Biomass burning emissions and potential air quality impacts of volatile organic compounds and other trace gases from fuels common in the US

    NASA Astrophysics Data System (ADS)

    Gilman, J. B.; Lerner, B. M.; Kuster, W. C.; Goldan, P. D.; Warneke, C.; Veres, P. R.; Roberts, J. M.; de Gouw, J. A.; Burling, I. R.; Yokelson, R. J.

    2015-12-01

    A comprehensive suite of instruments was used to quantify the emissions of over 200 organic gases, including methane and volatile organic compounds (VOCs), and 9 inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern US. A gas chromatograph-mass spectrometry (GC-MS) instrument provided extensive chemical detail of discrete air samples collected during a laboratory burn and was complemented by real-time measurements of organic and inorganic species via an open-path Fourier transform infrared spectroscopy (OP-FTIR) instrument and three different chemical ionization-mass spectrometers. These measurements were conducted in February 2009 at the US Department of Agriculture's Fire Sciences Laboratory in Missoula, Montana and were used as the basis for a number of emission factors reported by Yokelson et al. (2013). The relative magnitude and composition of the gases emitted varied by individual fuel type and, more broadly, by the three geographic fuel regions being simulated. Discrete emission ratios relative to carbon monoxide (CO) were used to characterize the composition of gases emitted by mass; reactivity with the hydroxyl radical, OH; and potential secondary organic aerosol (SOA) precursors for the 3 different US fuel regions presented here. VOCs contributed less than 0.78 % ± 0.12 % of emissions by mole and less than 0.95 % × 0.07 % of emissions by mass (on average) due to the predominance of CO2, CO, CH4, and NOx emissions; however, VOCs contributed 70-90 (±16) % to OH reactivity and were the only measured gas-phase source of SOA precursors from combustion of biomass. Over 82 % of the VOC emissions by mole were unsaturated compounds including highly reactive alkenes and aromatics and photolabile oxygenated VOCs (OVOCs) such as formaldehyde. OVOCs contributed 57-68 % of the VOC mass emitted, 41-54 % of VOC-OH reactivity, and aromatic-OVOCs such as benzenediols, phenols, and benzaldehyde

  3. Biomass burning emissions and potential air quality impacts of volatile organic compounds and other trace gases from temperate fuels common in the United States

    NASA Astrophysics Data System (ADS)

    Gilman, J. B.; Lerner, B. M.; Kuster, W. C.; Goldan, P. D.; Warneke, C.; Veres, P. R.; Roberts, J. M.; de Gouw, J. A.; Burling, I. R.; Yokelson, R. J.

    2015-08-01

    A comprehensive suite of instruments was used to quantify the emissions of over 200 organic gases, including methane and volatile organic compounds (VOCs), and 9 inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. A gas chromatograph-mass spectrometer (GC-MS) provided extensive chemical detail of discrete air samples collected during a laboratory burn and was complemented by real-time measurements of organic and inorganic species via an open-path Fourier transform infrared spectrometer (OP-FTIR) and 3 different chemical ionization-mass spectrometers. These measurements were conducted in February 2009 at the U.S. Department of Agriculture's Fire Sciences Laboratory in Missoula, Montana. The relative magnitude and composition of the gases emitted varied by individual fuel type and, more broadly, by the 3 geographic fuel regions being simulated. Emission ratios relative to carbon monoxide (CO) were used to characterize the composition of gases emitted by mass; reactivity with the hydroxyl radical, OH; and potential secondary organic aerosol (SOA) precursors for the 3 different US fuel regions presented here. VOCs contributed less than 0.78 ± 0.12 % of emissions by mole and less than 0.95 ± 0.07 % of emissions by mass (on average) due to the predominance of CO2, CO, CH4, and NOx emissions; however, VOCs contributed 70-90 (±16) % to OH reactivity and were the only measured gas-phase source of SOA precursors from combustion of biomass. Over 82 % of the VOC emissions by mole were unsaturated compounds including highly reactive alkenes and aromatics and photolabile oxygenated VOCs (OVOCs) such as formaldehyde. OVOCs contributed 57-68 % of the VOC mass emitted, 42-57 % of VOC-OH reactivity, and aromatic-OVOCs such as benzenediols, phenols, and benzaldehyde were the dominant potential SOA precursors. In addition, ambient air measurements of emissions from the Fourmile Canyon Fire

  4. Use of satellite data to constrain the model-calculated atmospheric lifetime for N2O - Implications for other trace gases

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien Dak; Weisenstein, Debra K.

    1991-01-01

    Model calculations of the zonal-mean concentrations of N2O in the upper stratosphere are presented showing that about 80 percent of N2O is removed in the stratosphere between 30 deg N and 30 deg S. A comparison of calculated N2O values with remote data on N2O concentrations obtained from Nimbus 7 SAMS instrument indicated that the two-dimensional model of Ko and Sze (1982) may have underestimated the concentration of N2O in the tropical lower stratosphere. It is concluded that the calculated lifetimes for N2O and chlorofluorocarbon-source gases could be 30 percent shorter than previously reported values.

  5. Trace metal mobilization from oil sands froth treatment thickened tailings exhibiting acid rock drainage.

    PubMed

    Kuznetsova, Alsu; Kuznetsov, Petr; Foght, Julia M; Siddique, Tariq

    2016-11-15

    Froth treatment thickened tailings (TT) are a waste product of bitumen extraction from surface-mined oil sands ores. When incubated in a laboratory under simulated moist oxic environmental conditions for ~450d, two different types of TT (TT1 and TT2) exhibited the potential to generate acid rock drainage (ARD) by producing acid leachate after 250 and 50d, respectively. We report here the release of toxic metals from TT via ARD, which could pose an environmental threat if oil sands TT deposits are not properly managed. Trace metal concentrations in leachate samples collected periodically revealed that Mn and Sr were released immediately even before the onset of ARD. Spikes in Co and Ni concentrations were observed both pre-ARD and during active ARD, particularly in TT1. For most elements measured (Fe, Cr, V, As, Cu, Pb, Zn, Cd, and Se), leaching was associated with ARD production. Though equivalent acidification (pH2) was achieved in leachate from both TT types, greater metal release was observed from TT2 where concentrations reached 10,000ppb for Ni, 5000ppb for Co, 3000ppb for As, 2000ppb for V, and 1000ppb for Cr. Generally, metal concentrations decreased in leachate with time during ARD and became negligible by the end of incubation (~450d) despite appreciable metals remaining in the leached TT. These results suggest that using TT for land reclamation purposes or surface deposition for volume reduction may unfavorably impact the environment, and warrants application of appropriate strategies for management of pyrite-enriched oil sands tailings streams. PMID:27443453

  6. Trace metal mobilization from oil sands froth treatment thickened tailings exhibiting acid rock drainage.

    PubMed

    Kuznetsova, Alsu; Kuznetsov, Petr; Foght, Julia M; Siddique, Tariq

    2016-11-15

    Froth treatment thickened tailings (TT) are a waste product of bitumen extraction from surface-mined oil sands ores. When incubated in a laboratory under simulated moist oxic environmental conditions for ~450d, two different types of TT (TT1 and TT2) exhibited the potential to generate acid rock drainage (ARD) by producing acid leachate after 250 and 50d, respectively. We report here the release of toxic metals from TT via ARD, which could pose an environmental threat if oil sands TT deposits are not properly managed. Trace metal concentrations in leachate samples collected periodically revealed that Mn and Sr were released immediately even before the onset of ARD. Spikes in Co and Ni concentrations were observed both pre-ARD and during active ARD, particularly in TT1. For most elements measured (Fe, Cr, V, As, Cu, Pb, Zn, Cd, and Se), leaching was associated with ARD production. Though equivalent acidification (pH2) was achieved in leachate from both TT types, greater metal release was observed from TT2 where concentrations reached 10,000ppb for Ni, 5000ppb for Co, 3000ppb for As, 2000ppb for V, and 1000ppb for Cr. Generally, metal concentrations decreased in leachate with time during ARD and became negligible by the end of incubation (~450d) despite appreciable metals remaining in the leached TT. These results suggest that using TT for land reclamation purposes or surface deposition for volume reduction may unfavorably impact the environment, and warrants application of appropriate strategies for management of pyrite-enriched oil sands tailings streams.

  7. Tracing carbon flow in an arctic marine food web using fatty acid-stable isotope analysis.

    PubMed

    Budge, S M; Wooller, M J; Springer, A M; Iverson, S J; McRoy, C P; Divoky, G J

    2008-08-01

    Global warming and the loss of sea ice threaten to alter patterns of productivity in arctic marine ecosystems because of a likely decline in primary productivity by sea ice algae. Estimates of the contribution of ice algae to total primary production range widely, from just 3 to >50%, and the importance of ice algae to higher trophic levels remains unknown. To help answer this question, we investigated a novel approach to food web studies by combining the two established methods of stable isotope analysis and fatty acid (FA) analysis--we determined the C isotopic composition of individual diatom FA and traced these biomarkers in consumers. Samples were collected near Barrow, Alaska and included ice algae, pelagic phytoplankton, zooplankton, fish, seabirds, pinnipeds and cetaceans. Ice algae and pelagic phytoplankton had distinctive overall FA signatures and clear differences in delta(13)C for two specific diatom FA biomarkers: 16:4n-1 (-24.0+/-2.4 and -30.7+/-0.8 per thousand, respectively) and 20:5n-3 (-18.3+/-2.0 and -26.9+/-0.7 per thousand, respectively). Nearly all delta(13)C values of these two FA in consumers fell between the two stable isotopic end members. A mass balance equation indicated that FA material derived from ice algae, compared to pelagic diatoms, averaged 71% (44-107%) in consumers based on delta(13)C values of 16:4n-1, but only 24% (0-61%) based on 20:5n-3. Our estimates derived from 16:4n-1, which is produced only by diatoms, probably best represented the contribution of ice algae relative to pelagic diatoms. However, many types of algae produce 20:5n-3, so the lower value derived from it likely represented a more realistic estimate of the proportion of ice algae material relative to all other types of phytoplankton. These preliminary results demonstrate the potential value of compound-specific isotope analysis of marine lipids to trace C flow through marine food webs and provide a foundation for future work.

  8. Trace element reactivity in FeS-rich estuarine sediments: influence of formation environment and acid sulfate soil drainage.

    PubMed

    Morgan, Bree; Rate, Andrew W; Burton, Edward D

    2012-11-01

    Iron monosulfides (FeS) precipitate during benthic mineralisation of organic C and are well known to have a strong influence on trace element bioavailability in sediments. In this study we investigate the reactivity of trace elements (As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Zn) in sediments containing abundant and persistent FeS stores, collected from a south-western Australian estuarine system. Our objective was to explore the influence of sediment formation conditions on trace element reactivity by investigating sediments collected from different environments, including estuarine, riverine and acid sulfate soil influenced sites, within a single estuarine system. In general, we found a higher degree of reactivity (defined by 1 mol/L HCl extractions) for Cd, Mn, Pb and Zn, compared with a lower reactivity of As, Co, Cr, Cu, Mo and Ni. Moderate to strong correlations (R(2)>0.4, P<0.05) were observed between AVS and reactive Cd, Co, Mn, Mo, Ni, Pb and Zn within many of the formation environments. In contrast, correlations between AVS and As, Cr and Cu were generally poor (not significant, R(2)<0.4, P>0.05). Based on their reactivity and correlations with AVS, it appears that interactions (sorption, co-precipitation) between FeS and Cd, Mn, Pb and Zn in many of the sediments from this study are probable. Our data also demonstrate that drainage from acid sulfate soils (ASS) can be a source of trace elements at specific sites. A principal components analysis of our reactive (1 mol/L HCl extractable) trace element data clearly distinguished sites receiving ASS drainage from the other non-impacted sites, by a high contribution from Fe-Co-Mn-Ni along the first principal axis, and contributions from higher S-As/lower reactive Pb along the second axis. This demonstrates that trace element reactivity in sediments may provide a geochemical signature for sites receiving ASS drainage.

  9. Somatic and genetic effects of the increase of carbon dioxide and other trace gases in the atmosphere through changes of radon and thoron exhalation rates and other factors

    NASA Astrophysics Data System (ADS)

    Okamoto, Kazuto

    Somatic and genetic effects of the increase of greenhouse gases are investigated. The exhalation rates of radon and thoron are affected by the climate change through the temperature rise itself, melting of snow and ice and the change of soil moisture, and the lung cancer rate is affected by these changes. On the other hand the greenhouse warming of the troposphere leads to cooling of the stratosphere, which protects the O 3 layer and reduces skin cancer. In the genetic side the temperature rise is harmful for sperm. The Rn increase leads to an increase of chromosome aberrations. Crude estimates of these effects show that the soil moisture effect is probably the largest, but the O 3 protection effect may also be significant.

  10. Constraining Gas Diffusivity-Soil Water Content Relationships in Forest Soils Using Surface Chamber Fluxes and Depth Profiles of Multiple Trace Gases

    NASA Astrophysics Data System (ADS)

    Dore, J. E.; Kaiser, K.; Seybold, E. C.; McGlynn, B. L.

    2012-12-01

    Forest soils are sources of carbon dioxide (CO2) to the atmosphere and can act as either sources or sinks of methane (CH4) and nitrous oxide (N2O), depending on redox conditions and other factors. Soil moisture is an important control on microbial activity, redox conditions and gas diffusivity. Direct chamber measurements of soil-air CO2 fluxes are facilitated by the availability of sensitive, portable infrared sensors; however, corresponding CH4 and N2O fluxes typically require the collection of time-course physical samples from the chamber with subsequent analyses by gas chromatography (GC). Vertical profiles of soil gas concentrations may also be used to derive CH4 and N2O fluxes by the gradient method; this method requires much less time and many fewer GC samples than the direct chamber method, but requires that effective soil gas diffusivities are known. In practice, soil gas diffusivity is often difficult to accurately estimate using a modeling approach. In our study, we apply both the chamber and gradient methods to estimate soil trace gas fluxes across a complex Rocky Mountain forested watershed in central Montana. We combine chamber flux measurements of CO2 (by infrared sensor) and CH4 and N2O (by GC) with co-located soil gas profiles to determine effective diffusivity in soil for each gas simultaneously, over-determining the diffusion equations and providing constraints on both the chamber and gradient methodologies. We then relate these soil gas diffusivities to soil type and volumetric water content in an effort to arrive at empirical parameterizations that may be used to estimate gas diffusivities across the watershed, thereby facilitating more accurate, frequent and widespread gradient-based measurements of trace gas fluxes across our study system. Our empirical approach to constraining soil gas diffusivity is well suited for trace gas flux studies over complex landscapes in general.

  11. Structure-selective hot-spot Raman enhancement for direct identification and detection of trace penicilloic acid allergen in penicillin.

    PubMed

    Zhang, Liying; Jin, Yang; Mao, Hui; Zheng, Lei; Zhao, Jiawei; Peng, Yan; Du, Shuhu; Zhang, Zhongping

    2014-08-15

    Trace penicilloic acid allergen frequently leads to various fatal immune responses to many patients, but it is still a challenge to directly discriminate and detect its residue in penicillin by a chemosensing way. Here, we report that silver-coated gold nanoparticles (Au@Ag NPs) exhibit a structure-selective hot-spot Raman enhancement capability for direct identification and detection of trace penicilloic acid in penicillin. It has been demonstrated that penicilloic acid can very easily link Au@Ag NPs together by its two carboxyl groups, locating itself spontaneously at the interparticle of Au@Ag NPs to form strong Raman hot-spot. At the critical concentration inducing the nanoparticle aggregation, Raman-enhanced effect of penicilloic acid is ~60,000 folds higher than that of penicillin. In particular, the selective Raman enhancement to the two carboxyl groups makes the peak of carboxyl group at C6 of penicilloic acid appear as a new Raman signal due to the opening of β-lactam ring of penicillin. The surface-enhanced Raman scattering (SERS) nanoparticle sensor reaches a sensitive limit lower than the prescribed 1.0‰ penicilloic acid residue in penicillin. The novel strategy to examine allergen is more rapid, convenient and inexpensive than the conventional separation-based assay methods.

  12. Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents

    SciTech Connect

    Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.

    2002-09-20

    The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (particle size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a filter house and the filter disk with a filter cake, operating continuously, simulating filter cake build-up and cleaning of the filter medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from

  13. Trace metals of an acid mine drainage stream using a chemical model (WATEQ) and sediment analysis

    SciTech Connect

    West, K.A. ); Wilson, T.P. . Dept. of Geology)

    1992-01-01

    The high metal contents common to the discharge of acid-mine drainage (AMD) from mines and mine spoils is an environmental concern to both government and industry. This paper reports the results of investigation of the behavior of metals in an AMD system at a former surface coal mine in Tuscarawas County, Oh. AMD discharges from seeps travels, in respective order through a laminar flow stream; a Typha-dominated wetland; a turbulent flow stream; and a sediment retention pond. Dissolved metals (Fe, Mn, Zn, Cr, Cd, Cu, and Al) major and minor components, and other parameters (pH, dissolved oxygen and Eh) were measured in the AMD water at each sample location. A chemical mineral equilibrium model (WATEQ) was used to predict the minerals which should precipitate at each site. Results suggest that the seeps are supersaturated and should be precipitating hematite, goethite and magnetite (iron oxides), and siderite (iron carbonate), whereas water of the other downstream sites were at or below equilibrium conditions for these minerals. The hydrogeochemistry of the AMD was further studied using sequential chemical attacks on the precipitate sediment surface coatings, in order to determine metal concentrations in the exchangeable, carbonate, Fe-Mn oxyhydroxide, and oxidizable fractions. The carbonate and exchangeable fractions of the precipitate are dominated by Ca and Fe, as well as Mg in the carbonate fraction. The Fe-Mn oxyhydroxide fraction contained Fe, Al, Mn, Mg, and trace metals, and also contained the greatest concentration of total elements in the system. The Fe-Mn oxyhydroxide is therefore, the major sink for metals of this AMD system. The decrease in the concentration of metals in the sediment precipitates in the downstream locations, is consistent with WATEQ and water analysis results.

  14. Comparison of four digestion procedures not requiring perchloric acid for the trace-element analysis of plant material

    SciTech Connect

    Knight, M. J.

    1980-05-01

    Perchloric acid (HClO/sub 4/) is often used to destroy organic material contained in plant tissue during sample preparation for trace-element analysis. However, since perchloric acid is an extremely strong oxidizing agent that can cause fire and explosion when in contact with combustible materials, its use is best avoided when proper safety equipment and training is unavailable. A comparison was made of four digestion procedures that do not require perchloric acid: wet digestion with nitric and sulfuric acids; wet digestion with nitric acid alone; a repeated wet digestion with nitric acid; and direct dry ashing. Each procedure was used to digest National Bureau of Standards orchard leaves (SRM 1571). To investigate the effect of possible filter paper adsorption on the determination of trace elements, digested samples were either filtered or not filtered before analysis. Atomic absorption spectrophotometry was employed to determine concentrations of As, Be, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, and Zn in each digested sample. Recoveries of each element and the relative error of each determination for each digestion procedure were then calculated. A statistical analysis of these data indicates that the direct dry ashing procedure is best suited for multi-element analysis. Dry ashing is appropriate to recover As, Be, Cr, Cu, Fe, Mn, Mo, Pb, and Zn. The nitric-sulfuric acids, nitric acid, and repeated nitric acid digestion procedures were deemed poor for multi-element analysis; however, each proved useful for the recovery of certain individual elements, including Cd, Pb, and Zn. Sample filtration significantly (p less than or equal to 0.05) lowered the recovery of Cr, Mn, Pb, and Zn from the digested samples. Conversely, the recovery of As, Mo, and Sr was significantly (p less than or equal to 0.05) higher in samples filtered before analysis when compared to the recovery of these elements in unfiltered samples.

  15. Impact of western Siberia heat wave 2012 on greenhouse gases and trace metal concentration in thaw lakes of discontinuous permafrost zone

    NASA Astrophysics Data System (ADS)

    Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Kulizhsky, S. P.; Vorobiev, S. N.

    2013-08-01

    During the anomalously hot summer in 2012, surface air temperatures in Western Siberia were 5 to 15 °C higher than those observed during the previous period of > 30 yr. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating of water in thermokarst ponds and lakes in discontinuous permafrost zones and compare these observations to previous field results obtained when the temperature was normal during the summer of 2010 in the same region. In 2012, thermokarst bodies of water shrank significantly, water levels dropped approximately 50 cm in large lakes and small (< 10-100 m2) ponds, and shallow soil depressions disappeared. Based on samples from ~ 40 bodies of water collected previously and in 2012, first-order features of changes in chemical composition in response to increased water temperatures (from 14.1 ± 2.2 to 23.8 ± 2.3 °C in 2010 and 2012, respectively) were established. In these thermokarst bodies of water that covered a full range of surface areas, the average conductivity and pH were almost unchanged, whereas dissolved organic carbon (DOC), Cl- and SO42- concentrations were higher by a factor of ~ 2 during summer 2012 compared to periods with normal temperatures. Similarly, most divalent metals and insoluble trivalent and tetravalent elements were more concentrated by a factor of 1.7-2.4 in the summer of 2012 than normal periods. The average concentrations of dissolved CO2 and CH4 during the hot summer of 2012 increased by factors of 1.4 and 4.9, respectively. For most of the trace elements bound to colloids, the degree of colloidal binding decreased by a factor of 1.44 ± 0.33 (for an average of 40 elements) during the hot summer of 2012 compared to normal periods. Increases in CO2 and CH4 concentrations with the decreasing size of the body of water were well-pronounced during the hot summer of 2012. The concentrations of CO2 and CH4 rose by factors of 5 and 150, respectively, in small (≤ 102 m2

  16. Present state of knowledge of the upper atmosphere: An assessment report; processes that control ozone and other climatically important trace gases

    NASA Technical Reports Server (NTRS)

    Watson, R. T.; Geller, M. A.; Stolarski, R. S.; Hampson, R. F.

    1986-01-01

    The state of knowledge of the upper atmosphere was assessed as of January 1986. The physical, chemical, and radiative processes which control the spatial and temporal distribution of ozone in the atmosphere; the predicted magnitude of ozone perturbations and climate changes for a variety of trace gas scenarios; and the ozone and temperature data used to detect the presence or absence of a long term trend were discussed. This assessment report was written by a small group of NASA scientists, was peer reviewed, and is based primarily on the comprehensive international assessment document entitled Atmospheric Ozone 1985: Assessment of Our Understanding of the Processes Controlling Its Present Distribution and Change, to be published as the World Meteorological Organization Global Ozone Research and Monitoring Project Report No. 16.

  17. Greenhouse Gases

    MedlinePlus

    ... Greenhouse Gases Come From Outlook for Future Emissions Recycling and Energy Nonrenewable Sources Oil and Petroleum Products ... Power Wave Power Ocean Thermal Energy Conversion Biomass Wood and Wood Waste Waste-to-Energy (MSW) Landfill ...

  18. Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults

    PubMed Central

    Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas S

    2015-01-01

    Background Homeostatic imbalance of trace elements such as iron (Fe), copper (Cu), and zinc (Zn) demonstrated adverse effects on brain function among older adults. Objective The present study aimed to investigate the effects of trace elements and the presence of anti-glutamic acid decarboxylase antibodies (GADAs) in human cognitive abilities among healthy older adults. Methods A total of 100 healthy subjects (65 males, 35 females; age range; 64–96 years) were recruited for this study. Based on Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) score, the participants were classified according to cognitive performance into normal (n=45), moderate (n=30), and severe (n=25). Cognitive functioning, leisure-time physical activity (LTPA), serum trace elements – Fe, Cu, Zn, Zn/Cu, and GADAs were assessed using LOTCA battery, pre-validated physical activity (PA) questionnaire, atomic absorption, and immunoassay techniques, respectively. Results Approximately 45% of the study population (n=45) had normal distribution of cognitive function and 55% of the study population (n=55) had abnormal cognitive function; they were classified into moderate (score 62–92) and severe (score 31–62). There was a significant reduction in the level of Zn and Zn/Cu ratio along with an increase in the level of Fe, Cu, and anti-GADAs in subjects of severe (P=0.01) and moderate (P=0.01) cognitive performance. LOTCA-cognitive scores correlated positively with sex, HbA1c, Fe, Cu, Zn, and Zn/Cu ratio, and negatively with age, PA, body mass index, and anti-GADAs. Significant inter-correlation was reported between serum trace element concentrations and anti-GADAs which suggest producing a cognitive decline via oxidative and neural damage mechanism. Conclusion This study found significant associations among trace elements, anti-GADAs, and cognitive function in older adults. The homeostatic balance of trace elements should be recommended among older adults for better cognitive

  19. Trace determination of nine haloacetic acids in drinking water by liquid chromatography-electrospray tandem mass spectrometry.

    PubMed

    Meng, Liping; Wu, Shimin; Ma, Fujun; Jia, Ai; Hu, Jianying

    2010-07-16

    A simple, fast and sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for trace levels of nine haloacetic acids (HAAs) in drinking water. Water samples were removed of residual chlorine by adding L-ascorbic acid, and directly injected after filtered by 0.22 microm membrane. Nine HAAs were separated by liquid chromatography in 7.5 min, and the limits of detection were generally between 0.16 and 0.99 microg/L except for chlorodibromoacetic acid (1.44 microg/L) and tribromoacetic acid (8.87 microg/L). The mean recoveries of nine target compounds in spiked drinking water samples were 80.1-108%, and no apparent signal suppression was observed. Finally, this method was applied to determine HAAs in the tap water samples collected from five waterworks in Shandong, China. Nine HAAs except for monochloroacetic acid, monobromoacetic acid, dibromochloroacetic acid and tribromoacetic acid were detected, and the total concentrations were 7.79-36.5 microg/L. The determination results well met the first stage of the Disinfectants/Disinfection By-Products (D/DBP) Rules established by U.S.EPA and Guidelines for Drinking-water Quality of WHO.

  20. Impacts of an African Green Revolution on Greenhouse Gases and Pollution Precursors: Nonlinear Trace N Gas Emission Responses to Incremental Increases in Fertilizer Inputs in a Western Kenyan Maize Field

    NASA Astrophysics Data System (ADS)

    Hickman, J. E.; Palm, C.

    2011-12-01

    Over the last several decades, agricultural soils in many parts of sub-Saharan Africa have become depleted of nitrogen (N) and other nutrients, creating challenges to achieving food security in many countries. At only 7 kg N ha-1 yr-1, average fertilizer application rates in the region are an order of magnitude lower than typical rates in the United States, and well below optimal levels. Increased use of nutrient inputs is a centerpiece of most African Green Revolution strategies, making it important to quantify the impacts of this change in practices as farmers begin moving towards 50-80 kg N ha-1 yr-1. Increased N inputs are invariably accompanied by losses of trace N gases to the atmosphere, including the greenhouse gas nitrous oxide (N2O), and nitric oxide (NO), a precursor to tropospheric ozone pollution. Several investigations of greenhouse gas emissions and one investigation of NO emissions from sub-Saharan agricultural systems have been conducted over the last 20 years, but they are few in number and were not designed to identify potentially important thresholds in the response of trace gas emissions to fertilization rate. Here we examine the response function of NO and N2O emissions to 6 different levels of inorganic fertilizer additions in a maize field in Yala, Kenya during the 2011 long rainy season. We used a randomized complete block design incorporating inorganic fertilizer treatments of 0, 50, 75, 100, 150, and 200 kg N ha-1 in 4 blocks. After each of 2 fertilizer applications, we measured trace gas fluxes daily, and conducted weekly measurements until trace gas emissions subsided to control levels. We fit the data to linear and exponential models relating N gas emissions to N input levels, and conducted a model comparison using AIC. Preliminary analysis suggests that NO emissions do respond in a non-linear fashion over the course of 67 days, as has been found in several commercial agroecosystems for N2O. Although N2O emissions responded linearly

  1. Agriculture's share in the emission of trace gases affecting the climate and some cause-oriented proposals for sufficiently reducing this share.

    PubMed

    Isermann, K

    1994-01-01

    This paper discusses agriculture's share in the world-wide emissions of climate-affecting gases and in the global warming potential (GWP). Proposals also are presented to reduce these emissions adequately, using a cause-oriented approach. Largely due to the fertilization and cultivation of agriculture as well as the burning of biomass, agriculture has a very high share in the anthropogenic emissions of NH(3), N(2)O, CH(4) and CO at >95%, 81%, 70% and 52%, respectively, while its share in the NO(x) and CO(2) emissions is relatively small at 35% and 21%. The GWP of agriculture, based on annually 16.1 x 10(9) tons of CO(2), approaches 63% of the GWP of the energy sector or 80% of the GWP of its CO(2) emissions. At 34% and 32%, respectively, the main originators in the GWP of agriculture would seem to be CO(2) (changing land use) and CH(4) (animal husbandry/rice cropping/biomass burning) followed at 15% by NO(2) (technical and biological N fixation/(cultivation and recultivation/biomass burning) and 10% and 9% by CO and NO(x). The GWP of 3 German dairy cows corresponds with 13.2 tonnes CO(2) per year the GWP of two average German automobiles. However, the ozone-destroying effect of N(2)O and the climate-relevant effects of NH(3) are not yet included here. As with the therapy for other 'modern' boundary-crossing environmental damages, such as acidification or eutrophication, global climate change therapy likewise needs a therapy for the respective effects of reactive compounds of carbon, nitrogen, phosphorous, and sulfur also emitted by agriculture. Proposals for reducing these emissions within the agricultural sector include need-oriented plant, animal and human nutrition, more efficient external and internal nutrient recycling, the cessation of further clearing by burning, along with intensified afforestation mainly in the tropics, targeted measures to reduce nutrient losses/emissions, and measures for more efficient use of nutrients in plant, animal and human

  2. [Determination of five kinds of trace ginkgolic acids in diterpene ginkgolides meglumine injection materials by LC-MS/MS].

    PubMed

    Si, Hai-hong; Li, Yan-jing; Xue, Jia; Huang, Wen-zhe; Wang, Zhen-zhong; Xiao, Wei

    2015-07-01

    To develop a LC-MS/MS method for the determination of five kinds of trace ginkgolic acids in diterpene ginkgolides meglumine injection materials, the column was Agilent ZORBAX Eclipse plus C18 (3.0 mm x 50 mm, 1.8 µm), and the mobile phase consisted of methanol-water (containing 0.2% formic acid) (95:5) at a flow rate of 0.5 mL · min(-1). The multiple reaction ion monitoring (MRM) with an ESI interface in the negative ion mode was selected. The results showed that the linear ranges of five kinds of ginkgolic acids were in the range of 0.2-36.0 µg · L(-1) (r ≥ 0.999 5). The lowest limit of quantification (LOQ) of ginkgo acid C13: 0, C15:1, C17:2, C15:0 and C17:1 were 0.18, 0.18, 0.21, 0.10 and 0.20 µg · L(-1), respectively. The average recovery was between 73.28% and 87.56%, and the average content of total ginkgolic acids in three batches of samples was in the range of 0.023-0.028 µg · g(-1), which was much lower than 2 µg · g(-1) prescribed in drug registration standards. This method is simple and rapid with high sensitivity, which can be used for the determination of five kinds of trace ginkgolic acids in diterpene ginkgolides meglumine injection materials.

  3. Determination of the profile of fatty acids of 4 species of Shigella spp by chromatography of gases.

    PubMed

    Robles Valderrama, E; Hurtado Bocanegra, M D; González Arreaga, M E; Ramírez García, P; Durán Díaz, A; Ayala Patiño, R; Martínez Pérez, M E

    2002-01-01

    Shigella boydii, Shigella flexneri, Shigella dysenteriae and Shigella sonnei were identified using gas chromatography instead of the traditional techniques. Their acid methyl esters profiles were determined using a gas chromatograph Hewlett Packard 5890A and a RSL-150 heliflex capillary column. A total of 192 samples were analyzed both reference strains (ATCC 8700, INDRE B2188, B2194 and B2199) and environmental isolates. 12 fatty acids were included in the profiles from which 3-hydroxytetradecanoic acid (peak 12), trans 9-octadecanoic acid (peak 22), heptadecanoic acid (peak 18) and octadecanoic acid (peak 23), were the most important for the differentiation of the species analyzed.

  4. Validation of the i-STAT system for the analysis of blood gases and acid-base status in juvenile sandbar shark (Carcharhinus plumbeus).

    PubMed

    Harter, T S; Morrison, P R; Mandelman, J W; Rummer, J L; Farrell, A P; Brill, R W; Brauner, C J

    2015-01-01

    Accurate measurements of blood gases and acid-base status require an array of sophisticated laboratory equipment that is typically not available during field research; such is the case for many studies on the stress physiology, ecology and conservation of elasmobranch fish species. Consequently, researchers have adopted portable clinical analysers that were developed for the analysis of human blood characteristics, but often without thoroughly validating these systems for their use on fish. The aim of our study was to test the suitability of the i-STAT system, the most commonly used portable clinical analyser in studies on fish, for analysing blood gases and acid-base status in elasmobranchs, over a broad range of conditions and using the sandbar shark (Carcharhinus plumbeus) as a model organism. Our results indicate that the i-STAT system can generate useful measurements of whole blood pH, and the use of appropriate correction factors may increase the accuracy of results. The i-STAT system was, however, unable to generate reliable results for measurements of partial pressure of oxygen (PO2) and the derived parameter of haemoglobin O2 saturation. This is probably due to the effect of a closed-system temperature change on PO2 within the i-STAT cartridge and the fact that the temperature correction algorithms used by i-STAT assume a human temperature dependency of haemoglobin-O2 binding; in many ectotherms, this assumption will lead to equivocal i-STAT PO2 results. The in vivo partial pressure of CO2 (PCO2) in resting sandbar sharks is probably below the detection limit for PCO2 in the i-STAT system, and the measurement of higher PCO2 tensions was associated with a large measurement error. In agreement with previous work, our results indicate that the i-STAT system can generate useful data on whole blood pH in fishes, but not blood gases. PMID:27293687

  5. Field measurements of trace gases emitted by prescribed fires in southeastern US pine forests using an open-path FTIR system

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Burling, I. R.; Mendoza, A.; Johnson, T. J.; Cameron, M.; Griffith, D. W. T.; Paton-Walsh, C.; Weise, D. R.; Reardon, J.; Yokelson, R. J.

    2014-01-01

    We report trace-gas emission factors from three pine-understory prescribed fires in South Carolina, US measured during the fall of 2011. The fires were more intense than many prescribed burns because the fuels included mature pine stands not subjected to prescribed fire in decades that were lit following an extended drought. Emission factors were measured with a fixed open-path Fourier transform infrared (OP-FTIR) system that was deployed on the fire control lines. We compare these emission factors to those measured with a roving, point sampling, land-based FTIR and an airborne FTIR deployed on the same fires. We also compare to emission factors measured by a similar OP-FTIR system deployed on savanna fires in Africa. The data suggest that the method used to sample smoke can strongly influence the relative abundance of the emissions that are observed. The majority of fire emissions were lofted in the convection column and were sampled by the airborne FTIR. The roving, ground-based, point sampling FTIR measured the contribution of individual residual smoldering combustion fuel elements scattered throughout the burn site. The OP-FTIR provided a ~ 30 m path-integrated sample of emissions transported to the fixed path via complex ground-level circulation. The OP-FTIR typically probed two distinct combustion regimes, "flaming-like" (immediately after adjacent ignition and before the adjacent plume achieved significant vertical development) and "smoldering-like." These two regimes are denoted "early" and "late", respectively. The path-integrated sample of the ground-level smoke layer adjacent to the fire from the OP-FTIR provided our best estimate of fire-line exposure to smoke for wildland fire personnel. We provide a table of estimated fire-line exposures for numerous known air toxics based on synthesizing results from several studies. Our data suggest that peak exposures are more likely to challenge permissible exposure limits for wildland fire personnel than shift

  6. Field measurements of trace gases emitted by prescribed fires in southeastern US pine forests using an open-path FTIR system

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Burling, I. R.; Mendoza, A.; Johnson, T. J.; Cameron, M.; Griffith, D. W. T.; Paton-Walsh, C.; Weise, D. R.; Reardon, J.; Yokelson, R. J.

    2013-07-01

    We report trace-gas emission factors from three pine-understory prescribed fires in South Carolina, US measured during the fall of 2011. The fires were more intense than many prescribed burns because the fuels included mature pine stands not subjected to prescribed fire in decades that were lit following an extended drought. The emission factors were measured with a fixed open-path Fourier transform infrared (OP-FTIR) system that was deployed on the fire control lines. We compare these emission factors to those measured with a roving, point sampling, land-based FTIR and an airborne FTIR that were deployed on the same fires. We also compare to emission factors measured by a similar OP-FTIR system deployed on savanna fires in Africa. The data suggest that the method used to sample smoke can strongly influence the relative abundance of the emissions that are observed. The majority of the fire emissions were lofted in the convection column and they were sampled by the airborne FTIR along with the downwind chemistry. The roving, ground-based, point sampling FTIR measured the contribution of actively located individual residual smoldering combustion fuel elements scattered throughout the burn site. The OP-FTIR provided a ~30 m path-integrated sample of emissions transported to the fixed path via complex ground-level circulation. The OP-FTIR typically probed two distinct combustion regimes, "flaming-like" (immediately after adjacent ignition and before the adjacent plume achieved significant vertical development) and "smoldering-like." These two regimes are denoted "early" and "late", respectively. The emission factors from all three systems were plotted versus modified combustion efficiency and for some species (e.g. CH4 and CH3OH) they fit a single trend suggesting that the different emission factors for these species were mainly due to the specific mix of flaming and smoldering that each system sampled. For other species, the different fuels sampled also likely

  7. A new laboratory facility to study the interactions of aerosols, cloud droplets/ice crystals, and trace gases in a turbulent environment: The Π Chamber

    NASA Astrophysics Data System (ADS)

    Cantrell, W. H., II; Chang, K.; Ciochetto, D.; Niedermeier, D.; Bench, J.; Shaw, R. A.

    2014-12-01

    A detailed understanding of gas-aerosol-cloud interaction within the turbulent atmosphere is of prime importance for an accurate understanding of Earth's climate system. As one example: While every cloud droplet began as an aerosol particle, not every aerosol particle becomes a cloud droplet. The particle to droplet transformation requires that the particle be exposed to some critical concentration of water vapor, which differs for different combinations of particle size and chemical composition. Similarly, the formation of ice particles in mixed phase clouds is also catalyzed by aerosol particles. Even in the simplest scenarios it is challenging to gain a full understanding of the aerosol activation and ice nucleation processes. At least two other factors contribute significantly to the complexity observed in the atmosphere. First, aerosols and cloud particles are not static entities, but are continuously interacting with their chemical environment, and therefore changing in their properties. Second, clouds are ubiquitously turbulent, so thermodynamic and compositional variables, such as water vapor or other trace gas concentrations, fluctuate in space and time. Indeed, the coupling between turbulence and microphysical processes is one of the major research challenges in cloud physics. We have developed a multiphase, turbulent reaction chamber, (dubbed the Π Chamber, after the internal volume of 3.14 cubic meters) designed to address the problems outlined above. It is capable of pressures ranging from sea level to ~ 100 mbar, and can sustain temperatures of +40 to -55 ºC. We can independently control the temperatures on the surfaces of three heat transfer zones. This allows us to establish a temperature gradient between the floor and ceiling inducing Rayleigh-Benard convection and inducing a turbulent environment. Interior surfaces are electropolished stainless steel to facilitate cleaning before and after chemistry experiments. At present, supporting

  8. Ground-based Measurements of Vertical Profiles and Columns of Atmospheric Trace Gases Over Toronto Using a New High-Resolution Fourier Transform Infrared Spectrometer

    NASA Astrophysics Data System (ADS)

    Wiacek, A.; Yashcov, D.; Strong, K.; Boudreau, L.; Rochette, L.; Roy, C.

    2002-12-01

    The University of Toronto Atmospheric Observatory (TAO) has recently been established at Toronto, Canada. TAO includes several instruments, with a DA8 Fourier Transform Spectrometer (DA8 FTS, manufactured by ABB Bomem Inc., Québec, Canada) serving as the primary instrument at the facility. The geographic position of TAO (43.66°N, 79.40°W) makes it well suited for long-term measurements of mid-latitude stratospheric ozone and related species, while its urban setting enables measurements of tropospheric pollution. The DA8 FTS is based on a Michelson interferometer with a maximum optical path difference of 250 cm, providing a maximum unapodized resolution of 0.0026 cm-1. It is currently equipped with KBr and CaF2 beamsplitters, and InSb and HgCdTe detectors, for coverage of the spectral range from 700 to 4100 cm-1. A new heliostat (manufactured by Aim Controls Inc., California, USA) provides active solar tracking, collecting the incoming solar radiation and directing it into the FTS. The TAO DA8 FTS incorporates a new optical design recently developed by ABB Bomem Inc., which results in a fixed optical axis through the beamsplitter (and a fixed focal point on the detector) as well as a more stable modulation efficiency. The new instrument optics will be discussed. Next, the performance of the instrument will be examined in the context of standard NDSC (Network for the Detection of Stratospheric Change) trace gas column and vertical profile retrieval techniques, which use least squares fitting algorithms (SFIT, SFIT2). TAO has been operational (weather permitting) since October 2001. We have been retrieving columns and vertical profiles of HCl, HF, CH4, OCS, C2H6, CO, N2O and NO2 since May 2002. A detailed error analysis of retrieved columns and vertical profiles has been undertaken for the above species. Future plans for the TAO FTS include comparing our measurements with satellite measurements made by MOPITT, OSIRIS, and the upcoming ACE and MAESTRO instruments

  9. Trace element status and fatty acids metabolism during healthy ageing: an example of a population from the Tunisian eastern coast.

    PubMed

    Sfar, Sonia; El Heni, Jihen; Laporte, François; Braham, Hamadi; Jawed, Abdelhafidh; Amor, Salah; Sfar, Mohamed Tahar; Kerkeni, Abdelhamid

    2012-03-01

    Micronutrients as well as essential fatty acids are indispensable for the correct functioning of the organism. The risk of disturbance in the associated nutrition and metabolism is expected to increase during ageing. In addition, it seems that trace elements are involved in the fatty acids metabolism. The aim of the present study was then to assess age-related changes in trace elements status and in plasma essential fatty acids composition with an emphasis on the desaturase activity estimation. Two hundred healthy Tunisian subjects (30-85 years old) were recruited and separated into two subgroups: elderly (65-85 years old) and middle-aged (30-60 years old). The findings revealed that plasma zinc and calcium concentrations significantly decreased according to age. The prevalence of zinc deficiency was therefore shown to increase in old age (over 60% of elderly subjects were deficient or at risk of deficiency). No age-related changes were obtained for copper or magnesium status. The Δ6 desaturase, involved in the EFAs conversion, was shown to decrease according to age and to be associated with the plasma zinc level. Since elderly subjects were at risk of nutritional imbalance, it would be interesting to set optimal dietary proportion. This will help to prevent age-associated alterations and diseases for a better and healthy ageing. PMID:22222317

  10. Organic amendments increase phylogenetic diversity of arbuscular mycorrhizal fungi in acid soil contaminated by trace elements.

    PubMed

    Montiel-Rozas, María Del Mar; López-García, Álvaro; Kjøller, Rasmus; Madejón, Engracia; Rosendahl, Søren

    2016-08-01

    In 1998, a toxic mine spill polluted a 55-km(2) area in a basin southward to Doñana National Park (Spain). Subsequent attempts to restore those trace element-contaminated soils have involved physical, chemical, or biological methodologies. In this study, the restoration approach included application of different types and doses of organic amendments: biosolid compost (BC) and leonardite (LEO). Twelve years after the last addition, molecular analyses of arbuscular mycorrhizal (AM) fungal communities associated with target plants (Lamarckia aurea and Chrysanthemum coronarium) as well as analyses of trace element concentrations both in soil and in plants were performed. The results showed an improved soil quality reflected by an increase in soil pH and a decrease in trace element availability as a result of the amendments and dosages. Additionally, the phylogenetic diversity of the AM fungal community increased, reaching the maximum diversity at the highest dose of BC. Trace element concentration was considered the predominant soil factor determining the AM fungal community composition. Thereby, the studied AM fungal community reflects a community adapted to different levels of contamination as a result of the amendments. The study highlights the long-term effect of the amendments in stabilizing the soil system. PMID:27072359

  11. Organic amendments increase phylogenetic diversity of arbuscular mycorrhizal fungi in acid soil contaminated by trace elements.

    PubMed

    Montiel-Rozas, María Del Mar; López-García, Álvaro; Kjøller, Rasmus; Madejón, Engracia; Rosendahl, Søren

    2016-08-01

    In 1998, a toxic mine spill polluted a 55-km(2) area in a basin southward to Doñana National Park (Spain). Subsequent attempts to restore those trace element-contaminated soils have involved physical, chemical, or biological methodologies. In this study, the restoration approach included application of different types and doses of organic amendments: biosolid compost (BC) and leonardite (LEO). Twelve years after the last addition, molecular analyses of arbuscular mycorrhizal (AM) fungal communities associated with target plants (Lamarckia aurea and Chrysanthemum coronarium) as well as analyses of trace element concentrations both in soil and in plants were performed. The results showed an improved soil quality reflected by an increase in soil pH and a decrease in trace element availability as a result of the amendments and dosages. Additionally, the phylogenetic diversity of the AM fungal community increased, reaching the maximum diversity at the highest dose of BC. Trace element concentration was considered the predominant soil factor determining the AM fungal community composition. Thereby, the studied AM fungal community reflects a community adapted to different levels of contamination as a result of the amendments. The study highlights the long-term effect of the amendments in stabilizing the soil system.

  12. Field measurements of trace gases emitted by prescribed fires in southeastern U.S. pine forests using an open-path FTIR system

    SciTech Connect

    Akagi, Sheryl; Burling, Ian R.; Mendoza, Albert; Johnson, Timothy J.; Cameron, Melanie; Griffith, David WT; Paton-Walsh, C.; Weise, David; Reardon, James; Yokelson, Robert J.

    2014-01-08

    We report trace-gas emission factors from three pine-understory prescribed fires in South Carolina, U.S. measured during the fall of 2011. The fires were an attempt to simulate high-intensity burns and the fuels included mature pine stands not frequently subjected to prescribed fire that were lit following a sustained period of drought. In this work we focus on the emission factor measurements made using a fixed open-path gas analyzer Fourier transform infrared (FTIR) system. We compare these emission factors with those measured using a roving, point sampling, land-based FTIR and an airborne FTIR that were deployed on the same fires. We also compare to emission factors measured by a similar open-path FTIR system deployed on savanna fires in Africa. The data suggest that the method in which the smoke is sampled can strongly influence the relative abundance of the emissions that are observed. The airborne FTIR probed the bulk of the emissions, which were lofted in the convection column and the downwind chemistry while the roving ground-based point sampling FTIR measured the contribution of individual residual smoldering combustion fuel elements scattered throughout the burn site. The open-path FTIR provided a fixed path-integrated sample of emissions produced directly upwind mixed with emissions that were redirected by wind gusts, or right after ignition and before the adjacent plume achieved significant vertical development. It typically probed two distinct combustion regimes, “flaming-like” (immediately after adjacent ignition) and “smoldering-like”, denoted “early” and “late”, respectively. The calculated emission factors from open-path measurements were closer to the airborne than to the point measurements, but this could vary depending on the calculation method or from fire to fire given the changing MCE and dynamics over the duration of a typical burn. The emission factors for species whose emissions are not highly fuel dependent (e.g. CH4 and

  13. Emission of trace gases and organic components in smoke particles from a wildfire in a mixed-evergreen forest in Portugal.

    PubMed

    Alves, Célia A; Vicente, Ana; Monteiro, Cristina; Gonçalves, Cátia; Evtyugina, Margarita; Pio, Casimiro

    2011-03-15

    On May 2009, both the gas and particulate fractions of smoke from a wildfire in Sever do Vouga, central Portugal, were sampled. Total hydrocarbons and carbon oxides (CO(2) and CO) were measured using automatic analysers with flame ionisation and non-dispersive infrared detectors, respectively. Fine (PM(2.5)) and coarse (PM(2.5-10)) particles from the smoke plume were analysed by a thermal-optical transmission technique to determine the elemental and organic carbon (EC and OC) content. Subsequently, the particle samples were solvent extracted and fractionated by vacuum flash chromatography into different classes of organic compounds. The detailed organic speciation was performed by gas chromatography-mass spectrometry. The CO, CO(2) and total hydrocarbon emission factors (g kg(-1) dry fuel) were 170 ± 83, 1485 ± 147, and 9.8 ± 0.90, respectively. It was observed that the particulate matter and OC emissions are significantly enhanced under smouldering fire conditions. The aerosol emissions were dominated by fine particles whose mass was mainly composed of organic constituents, such as degradation products from biopolymers (e.g. levoglucosan from cellulose, methoxyphenols from lignin). The compound classes also included homologous series (n-alkanes, n-alkenes, n-alkanoic acids and n-alkanols), monosaccharide derivatives from cellulose, steroid and terpenoid biomarkers, and polycyclic aromatic hydrocarbons (PAHs). The most abundant PAH was retene. Even carbon number homologs of monoglycerides were identified for the first time as biomarkers in biomass burning aerosols.

  14. Extent and bioavailability of trace metal contamination due to acid rock drainage in Pennask Creek, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Walls, L. D.; Li, L. Y.; Hall, K. J.

    2010-05-01

    Pennask Creek is one of the most important rainbow trout producing streams in British Columbia (BC). Much of the Pennask Creek watershed is located within a BC Parks Protected Area, which was set aside to protect the spawning and rearing habitat of this wild rainbow trout population. Construction of Highway 97C, which bisects the Pennask Creek watershed, resulted in the exposure of a highly pyritic rock formation, which began releasing acid rock drainage and causing metals to be leached into Highway Creek, a tributary of Pennask Creek. Previous studies commissioned by the BC Ministry of Transportation and Infrastructure indicate that Highway Creek yields fewer invertebrates and elevated levels of some metals in the water when compared with downstream sites in Pennask Creek. This study examines the impacts of this acid rock drainage and metal leaching by determining the extent of trace metal contamination in the water and sediments of the Pennask Creek watershed and determining the bioavailability of these trace metals. Preliminary results indicate concentrations of Al, Cu, and Zn in the water as well as levels of total As, Cu, Fe, Ni, and Zn in the sediments that are above the BC Water and Sediment Quality Guidelines for the Protection of Aquatic Life. The highest level of trace metal contamination is found in Highway Creek, downstream of Highway 97C, with concentrations generally returning to near background levels downstream of the confluence with Pennask Creek. Levels of Cu in the water and Zn in the sediments appear to be of greatest concern in areas furthest from the highway.

  15. Development of monitoring and control technology based on trace gas monitoring. Final report

    SciTech Connect

    Wu, M.; Shi, J.; Hickey, B.

    1997-07-01

    Trace gases are generated by many biological reactions. During anaerobic decomposition, trace levels of hydrogen (H{sub 2}) and carbon monoxide (CO) gases are produced. This work was designed to test how effectively hydrogen and CO could be to monitor high-rate anaerobic systems that has signficant mass transfer and complex hydraulics. An experimental program was designed to examine the behavior of an upflow anaerobic sludge blanket (UASB) reactor system under steady state and in response to organic loading perturbations. The responses of trace gases CO and H{sub 2} were tracked using an on-line, real-time gas-monitoring system linked to a computer-controlled data acquisition package. Data on conventional process parameters such as pH, chemical oxygen demand (COD), volatile fatty acids (VFAs) were concurrently collected.

  16. Toxic gases.

    PubMed Central

    Matthews, G.

    1989-01-01

    An overview of the widespread use of gases and some volatile solvents in modern society is given. The usual circumstances in which undue exposure may occur are described. The most prominent symptoms and general principles of diagnosis and treatment are given and are followed by more specific information on the commoner, more toxic materials. While acute poisonings constitute the greater part of the paper, some indication of chronic disorders arising from repeated or prolonged exposure is also given. PMID:2687827

  17. High-pressure acid dissolution of refractory alumina for trace element determination

    SciTech Connect

    Foner, H.A.

    1984-04-01

    A new high-pressure vessel (bomb) is described which uses nitrogen gas as the pressurizing medium and has the capability of measuring both the compensating pressure and the bomb temperature during heating. It is possible to dissolve quite large pieces (0.5 g) of unground (i.e., uncontaminated) single-crystal ..cap alpha..-alumina. The physical, electrical, and manufacturing properties of aluminas are all much affected by the levels of impurities present, and hence the determination of trace elements in these materials is of great practical importance.

  18. Exudation of organic acids by a marsh plant and implications on trace metal availability in the rhizosphere of estuarine sediments

    NASA Astrophysics Data System (ADS)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2005-10-01

    The aim of this work was to identify a variety of low molecular weight organic acids exuded by the sea rush Juncus maritimus collected at two locations with different sediment characteristics (sandy and muddy) and to examine whether specific differences in physico-chemical sediment characteristics influenced plant exudation. Just after collection, plant roots were rinsed and put in contact with deionised water for 2 h. In the obtained solution the organic acids, exuded by the plants, were determined by high performance liquid chromatography. Juncus maritimus was shown to be capable of releasing malonate and oxalate. Sediments and rhizosediments (sediment in contact with the plant roots and rhizomes, corresponding to the area of higher belowground biomass) from the areas where the plants had been collected were characterised in terms of physical and chemical composition, including acid volatile sulphide and total-recoverable metals (Pb, Cr, Cu, Zn, Ni and Cd). It was found that the extent of exudation varied markedly between sites. The identified organic acids were used as extractants of metals from sediments and rhizosediments and the results were compared with those provided by a very commonly used sequential extraction approach, which was carried out in parallel. This work demonstrates that J. maritimus can release organic compounds that can act as complexing agents of trace metal and therefore organic exudates should be accounted for when dealing with estuarine environment quality.

  19. Noble Gases

    NASA Astrophysics Data System (ADS)

    Podosek, F. A.

    2003-12-01

    The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the

  20. Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by 13C-fingerprinting

    NASA Astrophysics Data System (ADS)

    Riou, V.; Bouillon, S.; Serrão Santos, R.; Dehairs, F.; Colaço, A.

    2010-09-01

    Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0; 15:0; 16:0; 16:1(n - 7)c+t; 18:1(n - 13)c+t and (n - 7)c+t; 20:1(n - 7); 20:2(n - 9,15); 18:3(n - 7) and (n - 5,10,13) PLFA were labeled in the presence of H13CO3- (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3- (+H2S). In contrast, the 17:0; 18:0; 16:1(n - 9); 16:1(n - 8) and (n - 6); 18:1(n - 8); and 18:2(n - 7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n - 7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

  1. Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by 13C-fingerprinting

    NASA Astrophysics Data System (ADS)

    Riou, V.; Bouillon, S.; Serrão Santos, R.; Dehairs, F.; Colaço, A.

    2010-05-01

    Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0, 15:0, 16:1(n-7)c+t and 18:1(n-7)c+t PLFA were labeled in the presence of H13CO3- (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3- (+H2S). In contrast, the 16:1(n-9), 16:1(n-8) and (n-6), 18:1(n-8)c and (n-7), 20:1(n-7) and 18:2(n-7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n-7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

  2. Emissions of organic trace gases from savanna fires in southern Africa during the 1992 Southern African Fire Atmosphere Research Initiative and their impact on the formation of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Koppmann, R.; Khedim, A.; Rudolph, J.; Poppe, D.; Andreae, M. O.; Helas, G.; Welling, M.; Zenker, T.

    1997-08-01

    CO, CH4, and organic trace gases were measured in air samples collected during several flights with a DC-3 aircraft through the plumes from savanna fires and agricultural fires during the SAFARI 92 campaign in southern Africa in September and October 1992. In all samples a variety of higher molecular weight organic compounds was found, most of which are very reactive. More than 70 of the roughly 140 major components present could be identified. Typically, mixing ratios of several hundred parts per billion carbon of organic compounds were measured inside the plumes, corresponding to an emission ratio of total organic carbon relative to CO2 of up to 1%. About 50% of these emissions were in the form of oxygenated and unsaturated compounds. The contributions of still unknown compounds to the total emission of organic compounds add up to another 20-30%. The observed emission ratios relative to CO2 show a considerable variation depending on the fuel type and the burning stages of the fire. The lowest value of the emission ratio of the sum of all identified organic compounds relative to CO2 was found for a sugar cane fire with (1.7±0.7)×10-3 (ppb C/ppb CO2). For a large savanna fire in Kruger National Park the ratio was (7.4±1.6)×10-3 (ppb C/ppb CO2). The highest value was (13.7±0.9)×10-3 (ppb C/ppb CO2) for an uncontrolled fire of mainly wood and shrub in the Drakensberg region. Results of model calculations show that in biomass-burning plumes, reactive organic compounds contribute significantly to the formation of ozone, especially during the initial phase of photochemical processing.

  3. Acidity of vapor plume from cooling tower mixed with flue gases emitted from coal-fired power plant.

    PubMed

    Hlawiczka, Stanislaw; Korszun, Katarzyna; Fudala, Janina

    2016-06-01

    Acidity of products resulting from the reaction of flue gas components emitted from a coal-fired power plant with water contained in a vapor plume from a wet cooling tower was analyzed in a close vicinity of a power plant (710 m from the stack and 315 m from the cooling tower). Samples of this mixture were collected using a precipitation funnel where components of the mixed plumes were discharged from the atmosphere with the rainfall. To identify situations when the precipitation occurred at the same time as the wind directed the mixed vapor and flue gas plumes above the precipitation funnel, an ultrasound anemometer designed for 3D measurements of the wind field located near the funnel was used. Precipitation samples of extremely high acidity were identified - about 5% of samples collected during 12 months showed the acidity below pH=3 and the lowest recorded pH was 1.4. During the measurement period the value of pH characterizing the background acidity of the precipitation was about 6. The main outcome of this study was to demonstrate a very high, and so far completely underestimated, potential of occurrence of episodes of extremely acid depositions in the immediate vicinity of a coal-fired power plant. PMID:26950639

  4. Acidity of vapor plume from cooling tower mixed with flue gases emitted from coal-fired power plant.

    PubMed

    Hlawiczka, Stanislaw; Korszun, Katarzyna; Fudala, Janina

    2016-06-01

    Acidity of products resulting from the reaction of flue gas components emitted from a coal-fired power plant with water contained in a vapor plume from a wet cooling tower was analyzed in a close vicinity of a power plant (710 m from the stack and 315 m from the cooling tower). Samples of this mixture were collected using a precipitation funnel where components of the mixed plumes were discharged from the atmosphere with the rainfall. To identify situations when the precipitation occurred at the same time as the wind directed the mixed vapor and flue gas plumes above the precipitation funnel, an ultrasound anemometer designed for 3D measurements of the wind field located near the funnel was used. Precipitation samples of extremely high acidity were identified - about 5% of samples collected during 12 months showed the acidity below pH=3 and the lowest recorded pH was 1.4. During the measurement period the value of pH characterizing the background acidity of the precipitation was about 6. The main outcome of this study was to demonstrate a very high, and so far completely underestimated, potential of occurrence of episodes of extremely acid depositions in the immediate vicinity of a coal-fired power plant.

  5. Trace gases in the Antarctic Atmosphere

    NASA Technical Reports Server (NTRS)

    Heidt, L. E.; Pollock, W. H.; Lueb, R. A.; Henry, B. E.; Vedder, J. F.

    1989-01-01

    Whole-air samples collected aboard the NASA ER-2 and DC-8 aircraft as part of the Airborne Antarctic Ozone Experiment were analyzed in a field laboratory set up at Punta Arenas, Chile. Mixing ratios obtained from gas chromatographic analyses of these samples are presented for CH4, CO, N2O, CFCl3, CF2Cl2, C2F3Cl3, CH3CCl3, and CCl4. A comparison of CFCl3/N2O mixing ratios from the flights of September 16-29, 1987 provides evidence of sustained subsidence.

  6. Sulfuric acid vapor and other cloud-related gases in the Venus atmosphere - Abundances inferred from observed radio opacity

    NASA Technical Reports Server (NTRS)

    Steffes, P. G.; Eshleman, V. R.

    1982-01-01

    It is suggested that the absorbing characteristics of sulfuric acid vapor appear to reconcile what had been thought to be an inconsistency among measurements and deductions regarding the constituents of the Venus atmosphere and radio occultation, radar reflection, and radio emission measurements of its opacity. Laboratory measurements of sulfuric acid, sulfur dioxide, water vapor, and carbon dioxide are used to model relative contributions to opacity as a function of height in a way that is consistent with observations of the constituents and absorbing properties of the atmosphere. It is concluded that sulfuric acid vapor is likely to be the principal microwave absorber in the 30-50 km altitude range of the middle atmosphere of Venus.

  7. Trace analysis of acids and bases by conductometric titration with multiparametric non-linear regression.

    PubMed

    Coelho, Lúcia H G; Gutz, Ivano G R

    2006-03-15

    A chemometric method for analysis of conductometric titration data was introduced to extend its applicability to lower concentrations and more complex acid-base systems. Auxiliary pH measurements were made during the titration to assist the calculation of the distribution of protonable species on base of known or guessed equilibrium constants. Conductivity values of each ionized or ionizable species possibly present in the sample were introduced in a general equation where the only unknown parameters were the total concentrations of (conjugated) bases and of strong electrolytes not involved in acid-base equilibria. All these concentrations were adjusted by a multiparametric nonlinear regression (NLR) method, based on the Levenberg-Marquardt algorithm. This first conductometric titration method with NLR analysis (CT-NLR) was successfully applied to simulated conductometric titration data and to synthetic samples with multiple components at concentrations as low as those found in rainwater (approximately 10 micromol L(-1)). It was possible to resolve and quantify mixtures containing a strong acid, formic acid, acetic acid, ammonium ion, bicarbonate and inert electrolyte with accuracy of 5% or better.

  8. Acid deposition: effects on geochemical cycling and biological availability of trace elements. Report for September 1982-January 1985

    SciTech Connect

    Campbell, P.G.C.; Galloway, J.N.; Stokes, P.

    1985-01-01

    Acid deposition is caused by emissions of oxides of sulfur and nitrogen from such high temperature processes as fossil-fuel combustion and ore smelting. The emissions also contain elements present in the environment in trace amounts, for example, silver (Ag), arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), copper (Cu), mercury (Hg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), tin (Sn), tellurium (Te), thallium (Th), Vanadium (V), and zinc (Zn). With the exception of mercury, these elements are not naturally present in the atmosphere owing to their characteristically low volatilities. The shift from natural to human control of deposition of trace elements significantly perturbs the biogeochemical cycles of these potentially toxic substances. This report addresses the following: Do elevated rates of their deposition cause changes in aquatic and terrestrial ecosystems. What are the interactions between their deposition and the concurrent acidification of ecosystems. The report focuses on elements generally classified as very toxic and relatively accessible in the environment, i.e. the 17 listed above plus aluminum (Al). A significant bibliography accompanies the report.

  9. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    PubMed

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area. PMID:22358115

  10. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    PubMed

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area.

  11. Nitric acid passivation of Ti6Al4V reduces thickness of surface oxide layer and increases trace element release.

    PubMed

    Callen, B W; Lowenberg, B F; Lugowski, S; Sodhi, R N; Davies, J E

    1995-03-01

    Passivation of Ti6Al4V and cpTi implants using methods based on the ASTM-F86 nitric acid protocol are used with the intention of reducing their surface reactivity, and consequently the corrosion potential, in the highly corrosive biologic milieu. The ASTM-F86 passivation protocol was originally developed for surgical implants made of stainless steel and chrome cobalt alloy. Using X-ray photoelectron spectroscopy (XPS) to examine the effect of nitric acid passivation on the surface oxide layer of mill-annealed Ti6Al4V and cpTi, we have found that such treatment actually reduced the oxide thickness on the alloy while having no significant effect on the pure metal. These results correlated with observations obtained using graphite furnace atomic absorption spectrophotometry (GFAAS) to detect trace element release from solid, mill-annealed, Ti6Al4V and cpTi into serum-containing culture medium. We detected significantly greater levels of Ti, Al, and V in the presence of passivated compared to nonpassivated Ti6Al4V. In contrast, nitric acid passivation did not influence Ti release from mill-annealed cpTi. These results, derived from two mill-annealed Ti-based metals, would indicate that re-examination of ASTM-F86-based passivation protocols with respect to Ti6Al4V should be considered in view of the widespread use of this alloy for biomedical devices. PMID:7615579

  12. Detection of trace amino acid biomarkers in ice from extreme environments with the Mars Organic Analyzer

    NASA Astrophysics Data System (ADS)

    Jayarajah, Christine; Jayarajah, Christine; Botta, Oliver; Aubrey, Andrew; Parker, Eric; Bada, Jeffrey; Mathies, Richard

    A portable microfabricated capillary electrophoresis (CE) system named the Mars Organic Analyzer (MOA) has been developed to analyze fluorescently-labeled biomarkers including amino acids, amines, nucleobases, and amino sugars with the goal of life detection on Mars (1,2). This system consists of a multilayer microfabricated glass wafer containing electrophoresis channels as well as microfluidic valves and pumps for sample manipulation, a confocal laser excitation and fluorescence detection system, and integrated CE power supplies. The MOA has been successfully field tested in the Panoche Valley, CA and in the Atacama Desert, Chile, detecting amino acids at the ppb levels (3). In addition, this technology has been shown to be effective in screening the formation of biogenic amines during fermentation (4). The MOA is a part of the Urey instrument package that has been selected for the 2013 European ExoMars mission by ESA. The identification of recent gully erosion sites, observations of ice on and beneath the surface of Mars, and the discovery of large reservoirs of sub-surface ice on Mars point to water-ice as an important target for astrobiological analyses (5). In addition, the ice moons Europa and Enceladus are of astrobiological interest due to the possibility that they may contain liquid water under their ice crusts. Consequently, we explore here the use of the MOA instrument for the analysis of amino acids in polar ice samples. Soil extracts as well as concentrated icecore samples tend to be highly saline and inhomogeneous. Furthermore, brine pockets in ice form potential refugia for extant extra-terrestrial life, rendering near surface ice a key target for the search for a record of past life on the planet (6). Therefore, we have determined the effect of salinity on sample injection parameters in ice-core samples retrieved from Greenland. The amino acids valine, alanine/serine, glycine, glutamic acid, and aspartic acid were found in the parts

  13. Variations in trace metal and halogen ratios in magmatic gases through an eruptive cycle of the Pu'u O'o vent, Kilauea, Hawaii: July-August 1985

    SciTech Connect

    Miller, T.L.; Zoller, W.H. ); Crowe, B.M.; Finnegan, D.L. )

    1990-08-10

    Particle and gas samples were obtained before and after eruptive episode 35 in July and August 1985 at the fuming Pu'u O'o vent, Kilauea volcano, Hawaii. The sampling system employed consisted of a particle filter followed by four {sup 7}LiOH treated filters to collect acidic gases. The filters were analyzed using instrumental neutron activation analysis (INAA). The results indicate that Br/Cl and Re/Cl ratios do not fluctuate through an eruption cycle but the F/Cl, F/Br and metal/Cl ratios (In and Cd) do change through the cycle. An inverse relationship between F/Cl and metal/Cl was observed. The changes are probably due to influxes of relatively undegassed magma during the repose period releasing fume with lower F/Cl, F/BR and higher metal/Cl ratios. As the magma in the Pu'u O'o conduit gradually degasses either before or several days after an eruptive episode, F/Cl and F/Br ratios increase and the metal/Cl ratios decrease. One sample collected on July 24, two days before eruptive episode 35, did not follow this general trend. This can be explained by a gas pulse from a deeper, less degassed portion of magma making its way to the top of the conduit.

  14. Radon tracing of groundwater discharge into an Australian estuary surrounded by coastal acid sulphate soils

    NASA Astrophysics Data System (ADS)

    Santos, Isaac R.; Eyre, Bradley D.

    2011-01-01

    SummaryWidespread sulphidic deposits have accumulated in tropical coastal floodplains throughout the world. Sulphidic soils oxidize when floodplains are drained for urban and agricultural development. As a result, large amounts of sulphuric acid may be released to nearby waterways. Macropores may create excellent conditions for groundwater flow in coastal acid sulphate soils (CASS). An automated radon ( 222Rn) measurement system was used to quantify groundwater inputs into a tidally-dominated estuary that is known to be influenced by acid discharges from CASS (Richmond River Estuary, Australia). A high resolution radon survey along a 120-km long segment of the tidal river identified two areas of preferential groundwater inputs. Intensive time series measurements in one of those areas (the Tuckean Broadwater) demonstrated that groundwater inputs are highly variable over hourly and seasonal time scales and inversely related to surface water pH. Elevated radon concentrations (up to 12 dpm/L) and low pH (as low as 3.3) were observed in surface waters at low tide a few weeks after a large rain event. These results demonstrate that acidic waters are entering the estuary via tidally-modulated groundwater flow pathways. Groundwater discharge rates into drains in the Tuckean Swamp were estimated from a dual-assumption radon mass balance to be 0.09-0.16 and 0.56-0.89 m 3 s -1 during the dry and wet season, respectively (or 6-10 and 37-59 cm/day if the area is taken into account). While surface runoff increased only 2-fold in the wet season relative to the dry season, groundwater discharge rates increased ˜6-fold. Since groundwater can be a major driver of surface water quality, radon can be useful in CASS monitoring and management efforts.

  15. The influence of humic acid on the biological effects of selected trace metals

    SciTech Connect

    Stackhouse, R.A.

    1988-01-01

    The influence of humic acid (HA) on the biological effects of cadmium, hexavalent chromium, and two forms of trivalent chromium was assessed using common freshwater invertebrates. The acute toxicity was determined using Daphnia pulex, while D. magna was used in bioaccumulation studies. Final concentrations of HA tested were 0, 0.5, 5, and 50 mg/l. Humic acid was observed to significantly increase, decrease, or not influence both the acute toxicity and bioaccumulation of cadmium depending on HA concentration and time point examined. Additionally, dialysis studies were used to determine the influence of HA on the bioavailability of the metals. As with the biological effects, HA had little influence on the bioavailability of hexavalent chromium, while having a greater influence on cadmium and chromic chloride. There was a HA concentration dependent pattern of binding (a maximal decrease in percent free metal followed by metal release from HA) observed with cadmium and chromic chloride. This metal release from HA may have resulted from an associated time dependent decrease in pH of the surrounding water. Humic acid had little influence on the bioavailability of chrome lignosulfonate.

  16. Lewis Acid Based Sorption of Trace Amounts of RuCl3 by Polyaniline.

    PubMed

    Harbottle, Allison M; Hira, Steven M; Josowicz, Mira; Janata, Jiří

    2016-08-23

    A sorption process of RuCl3 in phosphate buffer by polyaniline (PANI) powder chemically synthesized from phosphoric acid was spectrophotometrically monitored as a function of time. It was determined that the sorption process follows the Langmuir and Freundlich isotherms, and their constants were evaluated. It was determined that chemisorption was the rate-controlling step. By conducting detailed studies, we assigned the chemisorption to Lewis acid based interactions of the sorbent electron pair localized at the benzenoid amine (-NH2) and quinoid imine (═NH) groups, with the sorbate, RuCl3, as the electron acceptor. The stability of the interaction over a period of ∼1 week showed that the presence of the Ru(III) in the PANI matrix reverses its state from emeraldine base to emeraldine salt, resulting in a change of conductivity. The partial electron donor based charge transfer is a slow process as compared to the sorption process involving Brønsted acid doping. PMID:27479848

  17. Effect of salicylic acid upon trace-metal sorption (Cd, Zn, Co, and Mn) onto alumina, silica, and kaolinite as a function of pH

    SciTech Connect

    Benyahya, L.; Garnier, J.M.

    1999-05-01

    The sorption of four trace metals (Cd, Zn, Co, and Mn) onto alumina, silica, and kaolinite, in the presence or absence of salicylic acid was investigated in batch experiments in the pH range from 4 to 9. The sorption was interpreted in terms of surface complexation using the diffuse layer model (DLM). Equilibrium parameters were optimized using the FITEQL program. The salicylic acid was only significantly sorbed onto the alumina and the sorption was modeled using the anionic monodentate surface complex. In the absence of salicylic acid, the sorption of the trace metals presented different pH edge behaviors, depending on the substrate. Using the cationic monodendate surface complex, the model fitted the experimental data well. In the presence of salicylic acid, at a given pH and depending on the substrate, the sorption of metals was (1) increased, suggesting the occurrence of ternary complexes; (2) reduced (sometimes totally inhibited), due to the complexation with dissolved salicylic acid; or (3) very weakly changed in terms of net effect compared to free-organic-ligand systems. Modeling of the trace-metal sorption in the presence of salicylic acid was performed using ternary surface complexes. In the acidic pH range, this allowed the experimental data to be simulated, but in the alkaline pH range, the model failed to simulate the decrease in sorption. Probable causes of the discrepancies between the experimental data and modeling results are discussed.

  18. Acid composition of particles and gases in a ponderosa pine forest during the BEACHON-RoMBAS campaign

    NASA Astrophysics Data System (ADS)

    Stark, H.; Yatavelli, L.; Thompson, S.; Kimmel, J. R.; Palm, B. B.; Day, D. A.; Campuzano-Jost, P.; Cubison, M. J.; Jayne, J.; Worsnop, D. R.; Thornton, J. A.; Jimenez, J. L.

    2012-12-01

    We present results from the high mass-resolution analysis of gas-phase and aerosol spectra collected with a chemical ionization high-resolution time-of-flight mass spectrometer, equipped with a micro-orifice volatilization impactor ("MOVI-HRToF-CIMS", Yatavelli and Thornton AS&T, 2010; Yatavelli et al., AS&T, 2012) during the 2011 Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study ("BEACHON-RoMBAS"). The study was conducted during July - August 2011 in a ponderosa pine forest in Colorado. Choosing acetate (CH3C(O)O-) as the reagent ion and developing analysis tools for formula identification and elemental analysis allowed us to identify hundreds of individual acids in aerosol spectra. Positive Matrix Factorization (PMF) analysis of the ion time series is useful to account for backgrounds in the different modes of operation and to separate several gas-phase and particulate factors with different volatility and composition. Results on aerosol composition, including nitrogen- and sulfur-containing species as well as information about elemental ratios (e.g. O:C, H:C) and average carbon oxidation state are presented. Most of the acids detected have between 1 and 10 carbons and average carbon oxidation states (OsC) between -1 and 1. This suggests the importance of monoterpenes and MBO as precursors of the measured acids. We will discuss these results with special consideration of fragmentation on the heated surfaces of the instrument.

  19. Microwave-assisted diluted acid digestion for trace elements analysis of edible soybean products.

    PubMed

    Barbosa, José Tiago P; Santos, Clarissa M M; Peralva, Vanessa N; Flores, Erico M M; Korn, Mauro; Nóbrega, Joaquim A; Korn, Maria Graças A

    2015-05-15

    A new method for the decomposition of soybean based edible products (soy extract, textured soy protein, transgenic soybeans, and whole soy flour) was developed to essential (Co, Cr, Cu, Fe, Mn, Ni, Se, V, and Zn) and non-essential (As, Ba, Cd, Pb, and Sr) trace elements determination by ICP OES and ICP-MS respectively. Effects related to the concentration of HNO3 (2.1-14.5 mol L(-1)) and the use of hydrogen peroxide on the efficiency of decomposition was evaluated based on the residual carbon content (RCC). It was demonstrated that 2.1 mol L(-1) HNO3 plus 1.0 mL H2O2 was suitable for an efficient digestion, since RCC was lower than 18% and the agreement with certified values and spike recoveries were higher than 90% for all analytes. The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: As (<0.007-0.040), Ba (0.064-10.6), Cd (<0.006-0.028), Co (0.012-102), Cr (0.56-5.88), Cu (6.53-13.9), Fe (24.9-126), Mn (16.4-35.2), Ni (0.74-4.78), Se (<2.90-25), Sr (2.48-20.1), Pb (<0.029-0.11), V (<0.027-20), and Zn (30.1-47.3). Soy-based foods investigated in this study presented variable composition in terms of essential and potentially toxic elements, which can be attributed to different methods of processing. PMID:25577072

  20. Microwave-assisted diluted acid digestion for trace elements analysis of edible soybean products.

    PubMed

    Barbosa, José Tiago P; Santos, Clarissa M M; Peralva, Vanessa N; Flores, Erico M M; Korn, Mauro; Nóbrega, Joaquim A; Korn, Maria Graças A

    2015-05-15

    A new method for the decomposition of soybean based edible products (soy extract, textured soy protein, transgenic soybeans, and whole soy flour) was developed to essential (Co, Cr, Cu, Fe, Mn, Ni, Se, V, and Zn) and non-essential (As, Ba, Cd, Pb, and Sr) trace elements determination by ICP OES and ICP-MS respectively. Effects related to the concentration of HNO3 (2.1-14.5 mol L(-1)) and the use of hydrogen peroxide on the efficiency of decomposition was evaluated based on the residual carbon content (RCC). It was demonstrated that 2.1 mol L(-1) HNO3 plus 1.0 mL H2O2 was suitable for an efficient digestion, since RCC was lower than 18% and the agreement with certified values and spike recoveries were higher than 90% for all analytes. The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: As (<0.007-0.040), Ba (0.064-10.6), Cd (<0.006-0.028), Co (0.012-102), Cr (0.56-5.88), Cu (6.53-13.9), Fe (24.9-126), Mn (16.4-35.2), Ni (0.74-4.78), Se (<2.90-25), Sr (2.48-20.1), Pb (<0.029-0.11), V (<0.027-20), and Zn (30.1-47.3). Soy-based foods investigated in this study presented variable composition in terms of essential and potentially toxic elements, which can be attributed to different methods of processing.

  1. Influence of trace elements on stabilization of aqueous solutions of ascorbic acid.

    PubMed

    Dolińska, Barbara; Ostróżka-Cieślik, Aneta; Caban, Artur; Rimantas, Klimas; Leszczyńska, Lucyna; Ryszka, Florian

    2012-12-01

    Together with vitamin C, zinc, selenium, manganese, and magnesium play a vital role in the preservation of organs scheduled for transplantation. In the present study, it is shown that addition of 1 mg/l of these elements influences the stability of 0.3 mM ascorbic acid solutions. The solution's stability was estimated using an accelerated stability test. The concentration of vitamin C was measured using a validated spectrophotometric method, which uses the reduction of 2,6-dichlorophenoloindophenol by ascorbic acid. Elevated temperatures, the factor accelerating substances' decomposition reaction rate, were used in the tests. The research was conducted at two temperatures at intervals of 10 °C: 80 ± 0.1 and 90 ± 0.1 °C. It was stated that the studied substances' decomposition occurred in accordance with the equation for first-order reactions. The function of the logarithmic concentration (log%C) over time was revealed to be rectilinear. This dependence was used to determine the kinetics of decomposition reaction rate parameters. The stabilization of vitamin C solutions was measured as the time in which 10 % of the substance decomposed at 20 and 0 °C. Addition of Se(IV) or Mg(II) ions significantly increase the stability of ascorbic acid solution (∼34 and ∼16 %, respectively), but Zn(II) causes a significant decrease in stability by ∼23 %. Addition of Mn(II) has no significant influence on vitamin C stability.

  2. Trace metal biogeochemistry in mangrove ecosystems: a comparative assessment of acidified (by acid sulfate soils) and non-acidified sites.

    PubMed

    Nath, Bibhash; Birch, Gavin; Chaudhuri, Punarbasu

    2013-10-01

    The generation of acidity and subsequent mobilization of toxic metals induced by acid sulfate soils (ASSs) are known to cause severe environmental damage to many coastal wetlands and estuaries of Australia and worldwide. Mangrove ecosystems serve to protect coastal environments, but are increasingly threatened from such ASS-induced acidification due to variable hydrological conditions (i.e., inundation-desiccation cycles). However, the impact of such behaviors on trace metal distribution, bio-availability and accumulation in mangrove tissues, i.e., leaves and pneumatophores, are largely unknown. In this study, we examined how ASS-induced acidifications controlled trace metal distribution and bio-availability in gray mangrove (Avicennia marina) soils and in tissues in the Kooragang wetland, New South Wales, Australia. We collected mangrove soils, leaves and pneumatophores from a part of the wetland acidified from ASS (i.e., an affected site) for detailed biogeochemical studies. The results were compared with samples collected from a natural intertidal mangrove forest (i.e., a control site) located within the same wetland. Soil pH (mean: 5.90) indicated acidic conditions in the affected site, whereas pH was near-neutral (mean: 7.17) in the control site. The results did not show statistically significant differences in near-total and bio-available metal concentrations, except for Fe and Mn, between affected and control sites. Iron concentrations were significantly (p values≤0.001) greater in the affected site, whereas Mn concentrations were significantly (p values≤0.001) greater in the control site. However, large proportions of near-total metals were potentially bio-available in control sites. Concentrations of Fe and Ni were significantly (p values≤0.001) greater in leaves and pneumatophores of the affected sites, whereas Mn, Cu, Pb and Zn were greater in control sites. The degree of metal bio-accumulation in leaves and pneumatophores suggest contrasting

  3. Trace metal biogeochemistry in mangrove ecosystems: a comparative assessment of acidified (by acid sulfate soils) and non-acidified sites.

    PubMed

    Nath, Bibhash; Birch, Gavin; Chaudhuri, Punarbasu

    2013-10-01

    The generation of acidity and subsequent mobilization of toxic metals induced by acid sulfate soils (ASSs) are known to cause severe environmental damage to many coastal wetlands and estuaries of Australia and worldwide. Mangrove ecosystems serve to protect coastal environments, but are increasingly threatened from such ASS-induced acidification due to variable hydrological conditions (i.e., inundation-desiccation cycles). However, the impact of such behaviors on trace metal distribution, bio-availability and accumulation in mangrove tissues, i.e., leaves and pneumatophores, are largely unknown. In this study, we examined how ASS-induced acidifications controlled trace metal distribution and bio-availability in gray mangrove (Avicennia marina) soils and in tissues in the Kooragang wetland, New South Wales, Australia. We collected mangrove soils, leaves and pneumatophores from a part of the wetland acidified from ASS (i.e., an affected site) for detailed biogeochemical studies. The results were compared with samples collected from a natural intertidal mangrove forest (i.e., a control site) located within the same wetland. Soil pH (mean: 5.90) indicated acidic conditions in the affected site, whereas pH was near-neutral (mean: 7.17) in the control site. The results did not show statistically significant differences in near-total and bio-available metal concentrations, except for Fe and Mn, between affected and control sites. Iron concentrations were significantly (p values≤0.001) greater in the affected site, whereas Mn concentrations were significantly (p values≤0.001) greater in the control site. However, large proportions of near-total metals were potentially bio-available in control sites. Concentrations of Fe and Ni were significantly (p values≤0.001) greater in leaves and pneumatophores of the affected sites, whereas Mn, Cu, Pb and Zn were greater in control sites. The degree of metal bio-accumulation in leaves and pneumatophores suggest contrasting

  4. In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian Study of Tropospheric Aerosols: An International Regional Experiment 2005

    NASA Astrophysics Data System (ADS)

    Li, Can; Marufu, Lackson T.; Dickerson, Russell R.; Li, Zhanqing; Wen, Tianxue; Wang, Yuesi; Wang, Pucai; Chen, Hongbin; Stehr, Jeffrey W.

    2007-11-01

    In situ measurements of trace gases and aerosol optical properties were made in March 2005 at Xianghe (39.798°N, 116.958°E, 35 m), a rural site about 70 km southeast, and generally downwind of the Beijing metropolitan area. High pollutant levels were observed during the experiment, with CO (1.09 ± 1.02 ppmv, average ± standard deviation), SO2 (17.8 ± 15.7 ppbv), NOy (26.0 ± 24.0 ppbv), aerosol scattering coefficients (bsp, (468 ± 472) × 10-6 m-1), and aerosol absorption coefficients (bap, (65 ± 75) × 10-6 m-1) all much higher than observed at some rural sites in the United States. O3 (29.1 ± 16.5 ppbv) was relatively low during this study, suggesting inactive photochemical processes. Strong synoptic fluctuations in pollutant levels were detected every 4-5 days during the experiment, as cold fronts passing over the region drastically reduced the ground-level pollution. Very little precipitation was measured during the whole observational period, implying pollutant uplift and transport by rain-free cold fronts and dry convection. The single scattering albedo (SSA) observed (0.81 in the morning and 0.85 in the afternoon) indicates strongly absorbing aerosols near surface. The observed CO/SO2 ratio (35.8) is higher than inventory values, but closer to the updated CO inventory of Streets et al. (2006) than to Streets et al. (2003) or Wang et al. (2005). The observed CO/NOy ratio agrees better with inventories. Further analysis suggests that such comparisons may shed some light on the quality of emission inventories, but quantification of any error requires more extensive measurements over longer period and larger areas, as well as direct characterization of emission sources, especially mobile sources and small boilers. Using black carbon (BC)/CO ratio from the experiment, BC emissions from China are estimated at about 1300 Gg (109 g)/yr, but could be as high as 2600 Gg/yr.

  5. Cell Model of In-cloud Scavenging of Highly Soluble Gases

    NASA Astrophysics Data System (ADS)

    Baklanov, A.; Elperin, T.; Fominykh, A.; Krasovitov, B.

    2012-04-01

    Transport of soluble gases in clouds is an integral part of the atmospheric transport of gases and is important for understanding the global distribution pattern of soluble trace gases. In the present study we investigated mass transfer during absorption of highly soluble gases such as hydrogen peroxide H2O2 and nitric acid HNO3 by stagnant cloud droplets in the presence of inert admixtures. Diffusion interactions between droplets, caused by the overlap of depleted of soluble gas regions around the neighboring droplets, are taken into account in the approximation of a cellular model of a gas-droplet suspension whereby a suspension is viewed as a periodic structure consisting of the identical spherical cells with periodic boundary conditions at the cell boundary. Using this model we determined temporal and spatial dependencies of the concentration of the soluble trace gas in a gaseous phase and in a droplet and calculated the dependence of the scavenging coefficient on time. It is shown that scavenging of highly soluble gases by cloud droplets leads to essential decrease of soluble trace gas concentration in the interstitial air. We found that scavenging coefficient for gas absorption by cloud droplets remains constant and sharply decreases only at the final stage of absorption. This assertion implies the exponential time decay of the average concentration of the soluble trace gas in the gaseous phase and can be used for the parameterization of gas scavenging by cloud droplets in the atmospheric transport modeling. In the calculations we employed gamma size distribution of cloud droplets. It was shown that despite of the comparable values of Henry's law constants for the hydrogen peroxide and the nitric acid, the nitric acid is scavenged more effectively by cloud than the hydrogen peroxide due to a major affect of the dissociation reaction on nitric acid scavenging. We obtained also the analytical expressions for the "equilibrium values" of concentration of the

  6. Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

    NASA Astrophysics Data System (ADS)

    Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

    2010-08-01

    lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum enhancements of 38.7 and 5.0 ppbv, or 383 and 319× the local background, respectively. The SO2 enhancements are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4 ethane and propane suggest low natural gas leakage despite its heavy use at the surface mining sites. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of α- and β-pinene were much higher over the oil sands (up to 217 and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

  7. Acid leachable trace metals in sediment cores from Sunderban Mangrove Wetland, India: an approach towards regular monitoring.

    PubMed

    Jonathan, M P; Sarkar, S K; Roy, P D; Alam, Md A; Chatterjee, M; Bhattacharya, B D; Bhattacharya, A; Satpathy, K K

    2010-02-01

    The paper presents the first document to identify the enrichment pattern of acid leachable trace metals (ALTMs) such as Fe, Mn, Cr, Cu, Ni, Pb, Cd, Co, Mo, Ag, As and Ba and their relationship with sediment quality parameters (pH, organic carbon, carbonates and texture) in core sediments (<63 microm particle size) from Indian Sunderban mangrove wetland, formed at the estuarine phase of the river Hugli (Ganges). Textural analysis reveals an overall predominance of mud. The results indicate that the change in pH values causes coagulation and precipitation of ALTMs. Fe and Mn have fairly close distribution patterns of enrichment in surface layers which might be ascribed to early diagnetic processes. The most prominent feature of ALTMs is the enrichment of Fe, Mn, Cr, Cu, Ni, Pb, and Ba in the surface-subsurface layers in the sediment cores, which is mainly attributed to the intense industrial and agricultural activities as well as drainage of untreated domestic sewage to this coastal region. The ALTMs also indicate their association with organic carbon and Fe-Mn oxyhydroxides. The enrichment is well--supported by the correlation, grouping and clustering of ALTMs in statistical analyses. Anthropogenic Factor values indicated ALTMs enrichment for all trace metals due to intense anthropogenic activities. Overall higher values of ALTMs in sediments in comparison to other Indian coastal regions indicate that they are mainly due to the uncontrolled anthropogenic activities in this mangrove estuarine complex. Statistical analyses suggest that five ALTMs (Cu, Pb, As, Mo, Ba) are attached to the organic particles and the clustering of elements separately also indicates that they are from external source. The result of the present study suggests the need for a regular monitoring program which will help to improve the quality of this potential wetland.

  8. Trace Amounts of Furan-2-Carboxylic Acids Determine the Quality of Solid Agar Plates for Bacterial Culture

    PubMed Central

    Hara, Shintaro; Isoda, Reika; Tahvanainen, Teemu; Hashidoko, Yasuyuki

    2012-01-01

    Background Many investigators have recognised that a significant proportion of environmental bacteria exist in a viable but non-culturable state on agar plates, and some researchers have also noticed that some of such bacteria clearly recover their growth on matrices other than agar. However, the reason why agar is unsuitable for the growth of some bacteria has not been addressed. Methodology/Principal Findings According to the guide of a bioassay for swarming inhibition, we identified 5-hydroxymethylfuran-2-carboxylic acid (5-HMFA) and furan-2-carboxylic acid (FA) as factors that inhibit bacterial swarming and likely inhibit extracellular polysaccharide production on agar. The furan-2-carboxylic acids 5-HMFA and FA effectively inhibited the swarming and swimming of several environmental bacteria at concentrations of 1.8 and 2.3 µg L−1 (13 and 21 nmol L−1), respectively, which are equivalent to the concentrations of these compounds in 0.3% agar. On Luria-Bertani (LB) plates containing 1.0% agar that had been previously washed with MeOH, a mixture of 5-HMFA and FA in amounts equivalent to their original concentrations in the unwashed agar repressed the swarming of Escherichia coli K12 strain W3110, a representative swarming bacterium. Conclusions/Significance Agar that contains trace amounts of 5-HMFA and FA inhibits the proliferation of some slow-growing or difficult-to-culture bacteria on the plates, but it is useful for single colony isolation due to the ease of identification of swarmable bacteria as the non-swarmed colonies. PMID:22848437

  9. Cycling of iron and trace metals in the sediments of acidic lakes

    SciTech Connect

    Gubala, C.P.

    1988-01-01

    This study focused on four lakes receiving acidic deposition located in the Adirondack Park, New York, U.S.A. The biogeochemistry of sediments and interstitial water along a depth transect in Big Moose, Lake was examined by chemical analysis of sediment and pore water. Solid phases of iron, manganese, aluminum, lead and zinc were quantified, using a sequential chemical extraction process. {sup 210}Pb dating, and equilibrium and diffusion transport modeling were used to assess the degree of post-depositional reprocessing of these metals. The sediment chemistry of Dart Lake, Lake Rondaxe and South Lake, were compared to the sediment processes observed in Big Moose Lake to assess inter-lake variability.

  10. STUDIES OF THE ACID-BASE EQUILIBRIUM IN DISEASE FROM THE POINT OF VIEW OF BLOOD GASES.

    PubMed

    Means, J H; Bock, A V; Woodwell, M N

    1921-01-31

    Carbon dioxide diagrams (Haggard and Henderson (9)) have been constructed for the blood of a series of hospital patients as a method of studying disturbances in their acid-base equilibrium. A diabetic with a low level of blood alkali, but with a normal blood reaction, a compensated acidosis in other words, showed a rapid return towards normal with no treatment but fasting and increased water and salt intake. A nephritic with a decompensated acidosis and a very low blood alkali was rapidly brought to a condition of decompensated alkalosis with a high blood alkali by the therapeutic administration of sodium bicarbonate. It is suggested that the therapeutic use of alkali in acidosis is probably only indicated in the decompensated variety, and that there it should be controlled carefully and the production of alkalosis avoided. The diagram obtained in three pneumonia patients suggested that they were suffering from a condition of carbonic acidosis, due perhaps to insufficient pulmonary ventilation. In two out of three cases of anemia the dissociation curve was found to lie at a higher level than normal. No explanation for this finding was offered. PMID:19868489

  11. Tracing and quantifying sources of fatty acids and steroids in amended cultivated soils.

    PubMed

    Jardé, Emilie; Gruau, Gérard; Jaffrezic, Anne

    2009-08-12

    Soluble organic fractions from soils of two agricultural sites from Brittany (France) have been analyzed to (i) identify the source of polar compounds in soils and (ii) evaluate the impact of organic fertilization and crop type on the distribution and concentration of polar compounds in soils. The main sources of polar compounds in soils are higher plants; they represent >70% of the polar compounds from the experimental sites and mainly originate from crop residues and animal manure. Crop type and animal manure application significantly increase the polar compound concentrations in soils. Among polar compounds, fatty acids cannot be used as specific markers because their distributions in soils whatever the crop type or organic fertilization type are the same. On the other hand, analysis of steroids provides interesting information. Cow and poultry manure applications increase only the concentration of steroids. Pig slurry fertilization modifies both the concentration and distribution of steroids. The identified pig slurry steroid fingerprint can persist in the soil for 9 years after the slurry application has been stopped. Those compounds are then robust markers to detect pig slurry contribution in soils.

  12. Tracing the biosynthetic source of essential amino acids in marine turtles using delta13C fingerprints.

    PubMed

    Arthur, Karen E; Kelez, Shaleyla; Larsen, Thomas; Choy, C Anela; Popp, Brian N

    2014-05-01

    Plants, bacteria, and fungi produce essential amino acids (EAAs) with distinctive patterns of delta13C values that can be used as naturally occurring fingerprints of biosynthetic origin of EAAs in a food web. Because animals cannot synthesize EAAs and must obtain them from food, their tissues reflect delta13C(EAA) patterns found in diet, but it is not known how microbes responsible for hindgut fermentation in some herbivores influence the delta13C values of EAAs in their hosts' tissues. We examined whether distinctive delta13C fingerprints of hindgut flora are evident in the tissues of green turtles (Chelonia mydas), which are known to be facultative hindgut fermenters. We determined delta13C(EAA) values in tissues of green turtles foraging herbivorously in neritic habitats of Hawaii and compared them with those from green, olive ridley, and loggerhead turtles foraging carnivorously in oceanic environments of the central and southeast Pacific Ocean. Results of multivariate statistical analysis revealed two distinct groups that could be distinguished based on unique delta13C(EAA) patterns. A three-end-member predictive linear discriminant model indicated that delta13C(EAA) fingerprints existed in the tissues of carnivorous turtles that resembled patterns found in microalgae, which form the base of an oceanic food web, whereas herbivorous turtles derive EAAs from a bacterial or seagrass source. This study demonstrates the capacity for delta13C fingerprinting to establish the biosynthetic origin of EAAs in higher consumers, and that marine turtles foraging on macroalgal diets appear to receive nutritional supplementation from bacterial symbionts in their digestive system. PMID:25000760

  13. Tracing the biosynthetic source of essential amino acids in marine turtles using delta13C fingerprints.

    PubMed

    Arthur, Karen E; Kelez, Shaleyla; Larsen, Thomas; Choy, C Anela; Popp, Brian N

    2014-05-01

    Plants, bacteria, and fungi produce essential amino acids (EAAs) with distinctive patterns of delta13C values that can be used as naturally occurring fingerprints of biosynthetic origin of EAAs in a food web. Because animals cannot synthesize EAAs and must obtain them from food, their tissues reflect delta13C(EAA) patterns found in diet, but it is not known how microbes responsible for hindgut fermentation in some herbivores influence the delta13C values of EAAs in their hosts' tissues. We examined whether distinctive delta13C fingerprints of hindgut flora are evident in the tissues of green turtles (Chelonia mydas), which are known to be facultative hindgut fermenters. We determined delta13C(EAA) values in tissues of green turtles foraging herbivorously in neritic habitats of Hawaii and compared them with those from green, olive ridley, and loggerhead turtles foraging carnivorously in oceanic environments of the central and southeast Pacific Ocean. Results of multivariate statistical analysis revealed two distinct groups that could be distinguished based on unique delta13C(EAA) patterns. A three-end-member predictive linear discriminant model indicated that delta13C(EAA) fingerprints existed in the tissues of carnivorous turtles that resembled patterns found in microalgae, which form the base of an oceanic food web, whereas herbivorous turtles derive EAAs from a bacterial or seagrass source. This study demonstrates the capacity for delta13C fingerprinting to establish the biosynthetic origin of EAAs in higher consumers, and that marine turtles foraging on macroalgal diets appear to receive nutritional supplementation from bacterial symbionts in their digestive system.

  14. Disodium N,N-bis-(dithiocarboxy)ethanediamine: synthesis, performance, and mechanism of action toward trace ethylenediaminetetraacetic acid copper (II).

    PubMed

    Xiao, Xiao; Ye, Maoyou; Yan, Pingfang; Qiu, Yiqin; Sun, Shuiyu; Ren, Jie; Dai, Yongkang; Han, Dajian

    2016-10-01

    A new effective multi-dithiocarbamate heavy metal precipitant, disodium N,N-bis-(dithiocarboxy) ethanediamine (BDE), was synthesized by mixing ethanediamine with carbon disulfide under alkaline conditions, and it was utilized for removing trace ethylenediaminetetraacetic acid copper (II) (EDTA-Cu) from wastewater. Its structure was confirmed by ultraviolet spectra, Fourier transform infrared spectra, scanning electron microscopy, thermogravimetric analysis, and elemental analysis. The removal performance of EDTA-Cu by BDE was evaluated according to BDE dosage, initial concentration, pH, and reaction time through single-factor experiments. With the optimized conditions of a pH range of 3-9, dosage ratio of BDE/Cu of 1:1, PAM dosage of 1 mg/L, and reaction time of 4 min, the removal efficiency of Cu(2+) was more than 98 % from simulated wastewater containing EDTA-Cu with initial concentrations of 5-100 mg/L. Treatment of actual EDTA-Cu wastewater showed that BDE performed superior effectiveness, and the average residential concentration of Cu(2+) was 0.115 mg/L. Besides, the stability of chelated precipitate and the reaction mechanism of BDE and EDTA-Cu were also introduced. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the chelated precipitate was non-hazardous and stable in weak acid and alkaline conditions. The BDE reacts with EDTA-Cu at a stoichiometric ratio, and the removal of Cu(2+) was predominantly achieved through the replacement reaction of BDE and EDTA-Cu.

  15. Disodium N,N-bis-(dithiocarboxy)ethanediamine: synthesis, performance, and mechanism of action toward trace ethylenediaminetetraacetic acid copper (II).

    PubMed

    Xiao, Xiao; Ye, Maoyou; Yan, Pingfang; Qiu, Yiqin; Sun, Shuiyu; Ren, Jie; Dai, Yongkang; Han, Dajian

    2016-10-01

    A new effective multi-dithiocarbamate heavy metal precipitant, disodium N,N-bis-(dithiocarboxy) ethanediamine (BDE), was synthesized by mixing ethanediamine with carbon disulfide under alkaline conditions, and it was utilized for removing trace ethylenediaminetetraacetic acid copper (II) (EDTA-Cu) from wastewater. Its structure was confirmed by ultraviolet spectra, Fourier transform infrared spectra, scanning electron microscopy, thermogravimetric analysis, and elemental analysis. The removal performance of EDTA-Cu by BDE was evaluated according to BDE dosage, initial concentration, pH, and reaction time through single-factor experiments. With the optimized conditions of a pH range of 3-9, dosage ratio of BDE/Cu of 1:1, PAM dosage of 1 mg/L, and reaction time of 4 min, the removal efficiency of Cu(2+) was more than 98 % from simulated wastewater containing EDTA-Cu with initial concentrations of 5-100 mg/L. Treatment of actual EDTA-Cu wastewater showed that BDE performed superior effectiveness, and the average residential concentration of Cu(2+) was 0.115 mg/L. Besides, the stability of chelated precipitate and the reaction mechanism of BDE and EDTA-Cu were also introduced. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the chelated precipitate was non-hazardous and stable in weak acid and alkaline conditions. The BDE reacts with EDTA-Cu at a stoichiometric ratio, and the removal of Cu(2+) was predominantly achieved through the replacement reaction of BDE and EDTA-Cu. PMID:27406222

  16. Poly(N-isopropylacrylamide-co-acrylic acid) nanogels for tracing and delivering genes to human mesenchymal stem cells.

    PubMed

    Park, Ji Sun; Yang, Han Na; Woo, Dae Gyun; Jeon, Su Yeon; Park, Keun-Hong

    2013-11-01

    Drugs, proteins, and cells can be macro- and micro-encapsulated by unique materials that respond to specific stimuli. The phases and hydrophobic interactions of these materials are reversibly altered by environmental stimuli such as pH and temperature. These changes can lead to self-assembly of the materials, which enables controlled drug release and safe gene delivery into cells and tissues. The fate of stem cells delivered by such methods is of great interest. The formation of transgenic tissues requires genes to be delivered safely into stem cells. A cell tracing vehicle and a gene delivery carrier were simultaneously introduced into human mesenchymal stem cells (hMSCs). A thermo-sensitive hydrogel, poly(N-isopropylacrylamide-co-acrylic acid) (p(NiPAAm-co-AAc)), was created to generate self-assembled nanoparticles with nanogel characteristics. Hydrophobic interactions mediated the binding of the carboxyl group on the outside of p(NiPAAm-co-AAc) with the amine group of iron oxide. Nanogels carrying iron oxide and a fluorescent dye were complexed with specific genes. These nanogels could be internalized by hMSCs, and the transplantation of these cells into mice was monitored by in vivo imaging. Self-assembled p(NiPAAm-co-dAAc) nanogels complexed with green fluorescent protein were highly expressed in hMSCs and are a potential material for gene delivery. PMID:23937912

  17. Trace metal partitioning over a tidal cycle in an estuary affected by acid mine drainage (Tinto estuary, SW Spain).

    PubMed

    Hierro, A; Olías, M; Cánovas, C R; Martín, J E; Bolivar, J P

    2014-11-01

    The Tinto River estuary is highly polluted with the acid lixiviates from old sulphide mines. In this work the behaviour of dissolved and particulate trace metals under strong chemical gradients during a tidal cycle is studied. The pH values range from 4.4 with low tide to 6.9 with high tide. Precipitation of Fe and Al is intense during rising tides and As and Pb are almost exclusively found in the particulate matter (PM). Sorption processes are very important in controlling the mobility (and hence bioavailability) of some metals and particularly affect Cu below pH 6. Above pH~6 Cu is desorbed, probably by the formation of Cu(I)-chloride complexes. Although less pronounced than Cu, also Zn desorption above pH 6.5 seems to occur. Mn and Co are affected by sorption processes at pH higher than ca. 6. Cd behaves conservatively and Ni is slightly affected by sorption processes.

  18. Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

    NASA Astrophysics Data System (ADS)

    Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

    2010-12-01

    products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort, such as upgraders (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum mixing ratios of 38.7 ppbv and 5.0 ppbv, or 383× and 319× the local background, respectively. These SO2 levels are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4, ethane and propane suggest low levels of natural gas leakage despite its heavy use at the surface mining sites. Instead the elevated CH4 levels are attributed to methanogenic tailings pond emissions. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of α-pinene and β-pinene were much greater over the oil sands (up to 217 pptv and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 pptv and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

  19. Donnan membrane speciation of Al, Fe, trace metals and REEs in coastal lowland acid sulfate soil-impacted drainage waters.

    PubMed

    Jones, Adele M; Xue, Youjia; Kinsela, Andrew S; Wilcken, Klaus M; Collins, Richard N

    2016-03-15

    Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values<3.9, 78 and 58% of Al and total Fe, respectively, were present as neutral or negatively-charged species. Complementary isotope dilution experiments with (55)Fe and (26)Al demonstrated that only soluble (i.e. no colloidal) species were present. Trivalent rare earth elements (REEs) were also mainly present (>70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO4)2(-) and/or Me-NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported. PMID:26780135

  20. Visual detection of trace copper ions based on copper-catalyzed reaction of ascorbic acid with oxygen

    NASA Astrophysics Data System (ADS)

    Hou, Xin Yan; Chen, Shu; Shun, Lian Ju; Zhao, Yi Ni; Zhang, Zhi Wu; Long, Yun Fei; Zhu, Li

    2015-10-01

    A visual detection method for trace Cu2+ in aqueous solutions using triangular silver nanoplates (abbreviated as TAgNPs) as the probe was developed. The method is based on that TAgNPs could be corroded in sodium thiosulfate (Na2S2O3) solutions. The absorption spectrum of TAgNPs solution changed when it is corroded by Na2S2O3. The reaction of oxygen with ascorbic acid (Vc) in the presence of a low concentration of Cu2+ generates hydrogen peroxide that reacts with Na2S2O3, which leads the concentration of Na2S2O3 in the solution to be decreased. Therefore, the reaction between TAgNPs and the reacted mixture of Na2S2O3/Vc/Cu2+ was prevented efficiently. When the Na2S2O3 concentration and reaction time are constant, the decrease in the concentration of Na2S2O3 is directly proportional to the Cu2+ concentration. Thus, morphology, color, and maximum absorption wavelength of TAgNPs changed with the change of Cu2+ concentration. The changed maximum absorption wavelength of TAgNPs (Δλ) is proportional to Cu2+ concentration in the range from 7.5 × 10-9 to 5.0 × 10-7 M with a correlation coefficient of r = 0.9956. Moreover, color change of TAgNP solution was observed clearly over a Cu2+ concentration range from 7.5 × 10-8 to 5.0 × 10-7 M. This method has been used to detect the Cu2+ content of a human hair sample, and the result is in agreement with that obtained by the atomic absorption spectroscopy (AAS) method.

  1. Donnan membrane speciation of Al, Fe, trace metals and REEs in coastal lowland acid sulfate soil-impacted drainage waters.

    PubMed

    Jones, Adele M; Xue, Youjia; Kinsela, Andrew S; Wilcken, Klaus M; Collins, Richard N

    2016-03-15

    Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values<3.9, 78 and 58% of Al and total Fe, respectively, were present as neutral or negatively-charged species. Complementary isotope dilution experiments with (55)Fe and (26)Al demonstrated that only soluble (i.e. no colloidal) species were present. Trivalent rare earth elements (REEs) were also mainly present (>70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO4)2(-) and/or Me-NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported.

  2. Migration of 18 trace elements from ceramic food contact material: influence of pigment, pH, nature of acid and temperature.

    PubMed

    Demont, M; Boutakhrit, K; Fekete, V; Bolle, F; Van Loco, J

    2012-03-01

    The effect of pH, nature of acid and temperature on trace element migration from ceramic ware treated with 18 commercially available glazes was studied. Besides of the well-studied lead and cadmium, migration of other toxic and non toxic elements such as aluminum, boron, barium, cobalt, chrome, copper, iron, lithium, magnesium, manganese, nickel, antimony, tin, strontium, titanium, vanadium, zinc and zirconium was investigated in order to evaluate their potential health hazards. Trace element concentrations were determined with Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). This study suggests that there is indeed a health risk concerning the possible migration of other elements than lead and cadmium. At low pH (2acid plays an important role. Citric and malic acid seem to be more aggressive to the glaze than acetic acid except for aluminum, barium, chromium, iron and magnesium. The migration kinetics between pH 2 and 3 in acetic acid of these exceptions also are more exponential while the other elements display a decreasing linear gradient. In ceramics used for this study (fired at 900 °C), a linear relationship between the migration and the temperature was observed. PMID:22265939

  3. Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: implications for land and water reclamation in tropical regions.

    PubMed

    Lottermoser, Bernd G; Ashley, Paul M

    2011-10-01

    This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions.

  4. Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: implications for land and water reclamation in tropical regions.

    PubMed

    Lottermoser, Bernd G; Ashley, Paul M

    2011-10-01

    This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions. PMID:21550704

  5. Biological production of products from waste gases

    DOEpatents

    Gaddy, James L.

    2002-01-22

    A method and apparatus are designed for converting waste gases from industrial processes such as oil refining, and carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various products, such as organic acids, alcohols, hydrogen, single cell protein, and salts of organic acids by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified.

  6. On the abiotic formation of amino acids. I - HCN as a precursor of amino acids detected in extracts of lunar samples. II - Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples

    NASA Technical Reports Server (NTRS)

    Yuasa, S.; Flory, D.; Basile, B.; Oro, J.

    1984-01-01

    Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.

  7. Depth profiling of ultra trace metal impurities in polytetrafluoroethylene wares by surface scraping and acid-vapor extraction followed by ICP-MS analysis.

    PubMed

    Tanaka, Masafumi; Takahashi, Makoto

    2002-10-01

    This paper describes the development of the depth profiling method of ultra trace metal impurities in polytetrafluoroethylene (PTFE) w