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Sample records for acid nitrogen dioxide

  1. Nitrogen dioxide

    Integrated Risk Information System (IRIS)

    Nitrogen dioxide ; CASRN 10102 - 44 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  2. The mechanism of low levels of nitrogen dioxide reaction with unsaturated fatty acid esters

    SciTech Connect

    Gallon, A.A.

    1990-01-01

    Nitrogen dioxide is a toxic air pollutant that exists at less than 0.5 ppm in the atmosphere. This toxic compound is known to initiate autoxidation of unsaturated fatty acids both in vivo and in vitro. When autoxidation occurs in vivo, membrane damage that can lead to cell death can occur. Low concentrations of nitrogen dioxide were shown to react with the polyunsaturated fatty acid esters, methyl linoleate and methyl linoleate, by a H-abstraction mechanism. However, methyl oleate, an unsaturated fatty acid ester, was demonstrated to react with a low concentration of nitrogen dioxide by only an addition mechanism. Although methyl oleate reacts by an addition mechanism, a 50:50 molar solution of methyl oleate and methyl linoleate reacted with a low level of nitrogen dioxide exclusively by a H-abstraction mechanism. Therefore, low levels of nitrogen dioxide will probably react with polyunsaturated fatty acid components of pulmonary lipids by a H-abstraction mechanism forming nitrous acid directly in the cell membrane. Vitamin E was demonstrated to be able to act as a preventative antioxidant in the nitrogen dioxide and methyl linoleate reactions; but vitamin C could not prevent nitrogen dioxide from reacting with methyl linoleate by a H-abstraction mechanism. These results suggest that low levels of nitrogen dioxide will react with polyunsaturated fatty acids by a H-abstraction mechanism and that vitamin E can be used to prevent the reaction from occurring.

  3. Nitrogen dioxide detection

    DOEpatents

    Sinha, Dipen N.; Agnew, Stephen F.; Christensen, William H.

    1993-01-01

    Method and apparatus for detecting the presence of gaseous nitrogen dioxide and determining the amount of gas which is present. Though polystyrene is normally an insulator, it becomes electrically conductive in the presence of nitrogen dioxide. Conductance or resistance of a polystyrene sensing element is related to the concentration of nitrogen dioxide at the sensing element.

  4. Sustainable synthesis of aldehydes, ketones or acids from neat alcohols using nitrogen dioxide gas, and related reactions.

    PubMed

    Naimi-Jamal, M Reza; Hamzeali, Hamideh; Mokhtari, Javad; Boy, Jürgen; Kaupp, Gerd

    2009-01-01

    Benzylic alcohols are quantitatively oxidized by gaseous nitrogen dioxide to give pure aromatic aldehydes. The reaction gas mixtures are transformed to nitric acid, which renders the processes free of waste. The exothermic gas-liquid or gas-solid reactions profit from the solubility of nitrogen dioxide in the neat benzylic alcohols. The acid formed impedes further oxidation of the benzaldehydes. The neat isolated benzaldehydes and nitrogen dioxide quantitatively give the benzoic acids. Solid long-chain primary alcohols are directly and quantitatively oxidized with nitrogen dioxide gas to give the fatty acids in the solid state. The oxidations with ubiquitous nitrogen dioxide are extended to solid heterocyclic thioamides, which gives disulfides, and to diphenylamine, which gives tetraphenylhydrazine. These sustainable (green) specific oxidation procedures produce no dangerous residues from the oxidizing agent or from auxiliaries. PMID:19115303

  5. Effect of acute nitrogen dioxide exposure on the composition of fatty acid associated with phospholipids in alveolar lavage

    SciTech Connect

    Kobayashi, T.; Noguchi, T.; Kikuno, M.; Kubota, K.

    1984-01-01

    In vivo exposure of rats to 10 ppm nitrogen dioxide (NO/sub 2/) for 12 h caused changes in fatty acids composition of alveolar lavage phospholipids. Among the fatty acid species, the relative ratio of palmitic acid, myristic acid and palmitoleic acid increased significantly. While the relative ratio of stearic acid, oleic acid, linoleic acid and arachidonic acid decreased significantly. Both the increase in the incorporation of palmitic acid in phosphatidylcholine which would be released into the alveoli and the increase in the release of phosphatidylcholine into the alveoli may account for the changes in the fatty acid composition of the present findings.

  6. Effects of nitrogen oxides, sulfur dioxide, and ferric ions on the corrosion of mild steel in concentrated sulfuric acid

    NASA Astrophysics Data System (ADS)

    Andersen, Terrell N.; Vanorden, Naola; Schlitt, W. Joseph

    1980-08-01

    Effects of nitrate ions, nitrous acid, sulfur dioxide, and ferric ions on the corrosion of mild steel in unstirred, concentrated sulfuric acid were determined in laboratory tests. Nitrate and nitrous acid at levels up to 1000 ppm accelerate corrosion. At concentrations greater than 1000 ppm nitrate passivates the steel. Sulfur dioxide and ferric ions have no detectable influence on the corrosion. Reaction mechanisms are presented to explain the observed effects. The impact of nitrogen oxides on the storage and handling of sulfide smelter by-product acid is discussed.

  7. Ambient concentrations of atmospheric ammonia, nitrogen dioxide and nitric acid in an intensive agricultural region

    NASA Astrophysics Data System (ADS)

    Zbieranowski, Antoni L.; Aherne, Julian

    2013-05-01

    The spatial and temporal distribution of ambient atmospheric gaseous reactive nitrogen (Nr) species concentrations (ammonia [NH3], nitrogen dioxide [NO2] and nitric acid [HNO3]) were measured at the field scale in an intensive agricultural region in southern Ontario, Canada. Atmospheric concentrations were measured with the Willems badge diffusive passive sampler (18 sites for NH3, 9 sites for NO2 and HNO3) for one year (April 2010-March 2011; under a two week measurement frequency) within a 15 km × 15 km area. Dry deposition was calculated using the inferential method and estimated across the entire study area. The spatial distribution of emission sources associated with agricultural activity resulted in high spatial variability in annual average ambient NH3 concentrations (<3->8 μg m-3 within a 2 km distance, coefficient of variation ˜50%) and estimated dry deposition (4-13 kg N ha-1 yr-1) between sample sites. In contrast, ambient concentrations and deposition of both NO2 (˜5.2->6.5 μg m-3; 1.0-1.5 kg N ha-1 yr-1) and HNO3 (0.6-0.7 μg m-3; 0.5-1 kg N ha-1 yr-1) had low variability (coefficient of variation <10%). The observed NH3 concentrations accounted for ˜70% of gaseous Nr dry deposition. High NH3 concentrations suggest that reduced nitrogen species (NHx) will continue to make up an increasing fraction of Nr deposition within intensive agricultural regions in southern Ontario under legislated nitrogen oxide emission reductions. Further, estimated total inorganic Nr deposition (15-28 kg N ha-1 yr-1) may lead to potential changes in soil processes, nutrient imbalance and altered composition of mycorrhiza and ground vegetation within adjacent semi-natural ecosystems (estimated at ˜10% of the study area).

  8. Antioxidative Reaction of Carotenes against Peroxidation of Fatty Acids Initiated by Nitrogen Dioxide: A Theoretical Study.

    PubMed

    Chen, Shau-Jiun; Huang, Li-Yen; Hu, Ching-Han

    2015-07-30

    In this study, we investigated the antioxidative functions of carotenes (CARs) against the peroxidation of lipids initiated by nitrogen dioxide using density functional theory. The hydrogen-atom transfer (HAT), radical adduct formation (RAF), and electron transfer (ET) mechanisms were investigated. We chose β-carotene (β-CAR) and lycopene (LYC) and compared their NO2(•) initiations and peroxidations with those of linoleic acid (LAH), the model of the lipid. We found that for CARs ET is more likely to occur in the most polar (water) environment than are HAT and RAF. In less polar environments, CARs react more readily with NO2(•) via HAT and RAF than does the lipid model, LAH. Comparatively, reaction barriers for the RAF between CARs and NO2(•) are smaller than those for the HAT. The additions of O2 to the radical intermediates O2N-CAR(•) and CAR(-H)(•) involve sizable barriers and are endergonic. Other than HAT of LAH, we revealed that lipid peroxidation is likely to be initiated by -NO2 addition and the subsequent barrierless addition of O2. Finally, LYC is a more effective antioxidative agent against NO2(•)-initiated lipid peroxidation than is β-CAR.

  9. Nitrogen dioxide induced changes in level of free fatty acids, triglyceride, esterified fatty acid, ganglioside and lipase activity in the guinea pig brain

    SciTech Connect

    Farahani, H.; Hasan, M. )

    1992-02-01

    The biochemical response to controlled inhalation of nitrogen dioxide (NO2) was studied in 18 male guinea pigs. Animals were exposed to 2.5, 5.0, and 10 ppm NO2 for 2h daily for 35 consecutive days, and the results compared with six control animals exposed to filtered air for 2h daily for same period. Five biochemical parameters, including triglyceride, free fatty acids, esterified fatty acid, ganglioside and lipase activity were measured immediately after the last day of exposure. At 2.5 ppm NO2 inhalation no significant changes occurred in any region of the central nervous system (CNS). While as the dose concentration was increased to 5 and 10 ppm nitrogen dioxide, significant dose-related alteration were observed in the levels of triglyceride, free fatty acid, esterified fatty acid, ganglioside and lipase activity in the different regions of the guinea pig CNS.

  10. Release of nitrous acid and nitrogen dioxide from nitrate photolysis in acidic aqueous solutions.

    PubMed

    Scharko, Nicole K; Berke, Andrew E; Raff, Jonathan D

    2014-10-21

    Nitrate (NO3(-)) is an abundant component of aerosols, boundary layer surface films, and surface water. Photolysis of NO3(-) leads to NO2 and HONO, both of which play important roles in tropospheric ozone and OH production. Field and laboratory studies suggest that NO3¯ photochemistry is a more important source of HONO than once thought, although a mechanistic understanding of the variables controlling this process is lacking. We present results of cavity-enhanced absorption spectroscopy measurements of NO2 and HONO emitted during photodegradation of aqueous NO3(-) under acidic conditions. Nitrous acid is formed in higher quantities at pH 2-4 than expected based on consideration of primary photochemical channels alone. Both experimental and modeled results indicate that the additional HONO is not due to enhanced NO3(-) absorption cross sections or effective quantum yields, but rather to secondary reactions of NO2 in solution. We find that NO2 is more efficiently hydrolyzed in solution when it is generated in situ during NO3(-) photolysis than for the heterogeneous system where mass transfer of gaseous NO2 into bulk solution is prohibitively slow. The presence of nonchromophoric OH scavengers that are naturally present in the environment increases HONO production 4-fold, and therefore play an important role in enhancing daytime HONO formation from NO3(-) photochemistry.

  11. Effect of simulated acid precipitation on algal fixation of nitrogen and carbon dioxide in forest soils

    SciTech Connect

    Chang, F.H.; Alexander, M.

    1983-01-01

    Three forest soils from areas exposed to acid precipitation were incubated for 21 days in the light to enhance the development of indigenous algae. The rates of nitrogen fixation (acetylene reduction) in the light and dark were significantly less if the soils were treated with simulated rain at pH 3.5 than at pH 5.6. The inhibition increased with increasing amounts of simulated rain at pH 3.5. The fixation of CO/sub 2/ in the light was significantly less in the three soils following their exposure to simulated precipitation at pH 3.5 than to the same solutions at pH 5.6, and the extent of suppression rose with increasing amounts of synthetic rain. It is suggested that algae in terrestrial ecosystems may be especially susceptible to acid precipitation.

  12. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2016-02-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

  13. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2015-10-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light emitting diodes (LEDs) and a grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high power LEDs with electronic on/off modulation, state-of-the-art cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350 and 80 pptv in 5 s. The accuracy is 5.8, 9.0 and 5.0 % limited mainly by the available absorption cross sections.

  14. Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants.

    PubMed

    Liu, Xiaofang; Hou, Fen; Li, Guangke; Sang, Nan

    2015-08-01

    Nitrogen dioxide (NO2) is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m(3) NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O2(-)) production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage.

  15. Formation of Amino Acids on the Sonolysis of Aqueous Solutions Containing Acetic Acid, Methane, or Carbon Dioxide, in the Presence of Nitrogen Gas.

    PubMed

    Dharmarathne, Leena; Grieser, Franz

    2016-01-21

    The sonolysis of aqueous solutions containing acetic acid, methane, or carbon dioxide in the presence of nitrogen gas was found to produce a number of different amino acids at a rate of ∼1 to 100 nM/min, using ultrasound at an operating power of 70 W and 355 kHz. Gas-phase elementary reactions are suggested, and discussed, to account for the formation of the complex biomolecules from the low molar mass solutes used. On the basis of the results, a new hypothesis is presented to explain the formation of amino acids under primitive atmospheric conditions and how their formation may be linked to the eventual abiotic genesis of life on Earth.

  16. Formation of Amino Acids on the Sonolysis of Aqueous Solutions Containing Acetic Acid, Methane, or Carbon Dioxide, in the Presence of Nitrogen Gas.

    PubMed

    Dharmarathne, Leena; Grieser, Franz

    2016-01-21

    The sonolysis of aqueous solutions containing acetic acid, methane, or carbon dioxide in the presence of nitrogen gas was found to produce a number of different amino acids at a rate of ∼1 to 100 nM/min, using ultrasound at an operating power of 70 W and 355 kHz. Gas-phase elementary reactions are suggested, and discussed, to account for the formation of the complex biomolecules from the low molar mass solutes used. On the basis of the results, a new hypothesis is presented to explain the formation of amino acids under primitive atmospheric conditions and how their formation may be linked to the eventual abiotic genesis of life on Earth. PMID:26695890

  17. Effects of depletion of ascorbic acid or nonprotein sulfhydryls on the acute inhalation toxicity of nitrogen dioxide, ozone, and phosgene

    SciTech Connect

    Slade, R.; Highfill, J.W.; Hatch, G.E.

    1989-01-01

    The effect of depleting lung ascorbic acid (AH{sub 2}) and nonprotein sulfhydryls (NPSH) on the acute inhalation toxicity of nitrogen dioxide (NO{sub 2}), ozone (O{sub 3}), and phosgene (COCl{sub 2}) was investigated in guinea pigs. The increase in bronchoalveolar lavage (BAL) fluid protein (an indicator of alveolar-capillary damage leading to increased permeability) was measured 16 to 18 hr following a 4 hr exposure to the gas in animals deficient in (AH{sub 2}) or NPSH. Gas concentrations were chosen which produced low but significant increases in BAL protein. Lung (AH{sub 2}) was lowered to about 20% of control by feeding rabbit chow for 2 weeks. Lung NPSH was lowered to about 50% of control by injecting a mixture of buthionine S,R-sulfoximine (BSO) and diethylmaleate (DEM) (2.7 and 1.2 mmol/kg respectively). BSO/DEM did not affect the lung concentrations of (AH{sub 2}) or alpha-tocopherol. AH{sub 2} depletion caused a 6 fold and a 3 fold enhancement in the toxicity of 5 ppm and 10 ppm (NO{sub 2}), and a 6 fold enhancement in the toxicity of 0.5 ppm (O{sub 3}), but did not affect toxicity of 1.0 ppm (O{sub 3}). AH{sub 2} depletion did not affect phosgene toxicity (at 0.25 ppm and 0.5 ppm).

  18. The photolysis of chlorine in the presence of ozone, nitric acid and nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Stuper, W. W.

    1979-01-01

    The following three systems were investigated: the Cl2-O3 system, the Cl2-O2-NO system and the Cl2-NO2-M system. In the first system, the reaction between ClO and O3, the reaction between OClO and O3, and the mechanism of the Cl2-O3 system were studied. In the second system, the reaction between ClOO and NO was investigated. In the last system, the reaction between Cl and NO2 was investigated as well as the kinetics of the chemiluminescence of the Cl-NO2-O3 reaction. In the first system, Cl2 was photolyzed at 366 nm in the presence of O3 within the temperature range 254-297 K. O3 was removed with quantum yields of 5.8 + or - 0.5, 4.0 + or - 0.3, 2.9 + or - 0.3 and 1.9 + or - 0.2 at 297, 283, 273, and 252 K respectively, invariant to changes in the initial O3 or Cl2 concentration, the extent of conversion or the absorbed intensity, I sub a. The addition of nitrogen had no effect on -phi(03). The Cl2 removal quantum yields were 0.11 + or - 0.02 at 297 K for Cl2 conversions of about 30%, much higher than expected from mass balance considerations based on the initial quantum yield of 0.089 + or - 0.013 for OClO formation at 297 K. The final chlorine-containing product was Cl2O7. It was produced at least in part through the formation of OClO as an intermediate which was also observed with an initial quantum yield of phi sub i(OClO) = 2500 exp(-(3025 + or - 625)/T) independent of (O3) or I sub a.

  19. Continuous analysis of nitrogen dioxide in gas streams of plants

    NASA Technical Reports Server (NTRS)

    Durkin, W. T.; Kispert, R. C.

    1969-01-01

    Analyzer and sampling system continuously monitors nitrogen dioxide concentrations in the feed and tail gas streams of a facility recovering nitric acid. The system, using a direct calorimetric approach, makes use of readily available equipment and is flexible and reliable in operation.

  20. Indoor nitrogen dioxide and childhood respiratory illness.

    PubMed

    Pilotto, L S; Douglas, R M

    1992-09-01

    Nitrogen dioxide is produced from the combustion of fossil fuels and as an emission from gas-fired appliances, and is also a component of tobacco smoke. Nitrogen dioxide has been shown in experimental animals to be toxic to the respiratory tract. A n number of recent studies have suggested that children exposed to significant levels of nitrogen dioxide in the home may be more susceptible to respiratory illness than children exposed to normal ambient levels. Respiratory illness is a major cause of morbidity in children everywhere. Here, we review the available evidence of this association and explore methodological issues in measurement of nitrogen dioxide exposure--misclassification of subjects, symptom bias and confounding. It has recently been shown that some New South Wales school rooms, where unflued gas heaters are often used as a source of warmth, have nitrogen dioxide levels which are above recommended ambient levels for outside air. This has underlined the need for setting standards for indoor levels of various pollutants, and cohort studies are suggested, to include personal monitoring and prospective data collection techniques. PMID:1482716

  1. The Development of a Nitrogen Dioxide Sonde

    NASA Astrophysics Data System (ADS)

    Sluis, Wesley; Allaart, Marc; Piters, Ankie; Gast, Lou

    2010-05-01

    Nitrogen dioxide is an important pollutant in the atmosphere, it is toxic for living species, it forms photochemical tropospheric ozone, and acid rain. There is a growing number of space-borne instruments to measure nitrogen dioxide concentrations in the atmosphere, but validation of these instruments is hampered by lack of ground-based and in-situ profile measurements. The Royal Netherlands Meteorological Institute (KNMI) has developed a working NO2 sonde. The sonde is attached to a small meteorological balloon and measures a tropospheric NO2 profile. The NO2 sonde has a vertical resolution of 5 meter, and a measurement range between 1 and 100 ppbv. The instrument is light in weight (±300 gram), cheap (disposable), energy efficient and not harmful to the environment or the person who finds the package after use. Therefore the popular molybdenum catalytic converter or a photomultiplier tube can not be used. Instead the sonde uses the chemiluminescent reaction of NO2 in an aqueous luminol solution. The NO2- luminol reaction produces a faint blue/purple light (± 425 nm), which is detected by an array of silicon photodiodes. The instrument is equipped with a reservoir filled with luminol solution. A small piezoelectric diaphragm pump, pumps the luminol solution into a reaction vessel. A Teflon air pump forces the ambient air into the reaction vessel. The NO2 in the ambient air reacts with the luminol solution, and the emitted light is detected by an array of silicon photodiodes which are mounted on the reaction vessel. The generated current in the photodiodes is amplified and relayed to the ground by a Vaisala (RS92) radiosonde. The reaction vessel and the amplifiers are mounted in a tin can, to shield against electrostatic and radio interference, and stray light. All the air tubes used for the instrument are made of Teflon. The luminol solution is optimised to be specific to NO2. Sodium sulphate, sodium EDTA and Triton X-100 are added to the luminol solution to

  2. Collagen breakdown and nitrogen dioxide inhalation.

    PubMed

    Hatton, D V; Leach, C S; Nicogossian, A E

    1977-01-01

    Measurements of urinary hydroxylysine glycosides indicate that considerable collagen degradation occurred during the reentry into the earth's atmosphere of the American astronauts of the Apollo-Soyuz mission. Since the crew accidentally inhaled nitrogen dioxide, a recognized pulmonary irritant, and showed clinical and roentgenographic signs of diffuse chemical pneumonitis, it is likely that collagen degradation occurred in the pulmonary parenchyma.

  3. Effects of acid irrigation on carbon dioxide evolution, extractable nitrogen, phosphorus, and aluminum in a deciduous forest soil

    SciTech Connect

    Johnson, D.W.; Todd, D.E.

    1984-01-01

    A study was initiated to determine the effects of sulfuric and nitric acid irrigation on CO/sub 2/ evolution, and N, P, and Al availability in a deciduous forest soil. Irrigation with H/sub 2/O, H/sub 2/SO/sub 4/, or HNO/sub 3/ at 0.05 mol (p/sup +/) m/sup -2/ and 0.5 mol (p/sup +/) m/sup -2/ for 1 yr had no consistent effect on CO/sub 2/ evolution, soil NH/sub 4//sup +/, extractable P, or extractable Al in a deciduous forest soil under field conditions. Irrigation with HNO/sub 3/ caused temporary increases in soil NO/sub 3//sup -/, but irrigation with H/sub 2/SO/sub 4/ had no effect on soil NO/sub 3//sup -/. Nitrogen mineralization and nitrification by aerobic incubation were also unaffected by treatments. Seasonal variations in CO/sub 2/ evolution, NH/sub 4//sup +/, and extractable P were pronounced, with peaks in CO/sub 2/ evolution, NH/sub 4//sup +/, in June and a peak extractable P in August. 19 references, 2 tables.

  4. 21 CFR 868.2385 - Nitrogen dioxide analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nitrogen dioxide analyzer. 868.2385 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2385 Nitrogen dioxide analyzer. (a) Identification. The nitrogen dioxide analyzer is a device intended to measure the concentration of...

  5. 21 CFR 868.2385 - Nitrogen dioxide analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nitrogen dioxide analyzer. 868.2385 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2385 Nitrogen dioxide analyzer. (a) Identification. The nitrogen dioxide analyzer is a device intended to measure the concentration of...

  6. 21 CFR 868.2385 - Nitrogen dioxide analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nitrogen dioxide analyzer. 868.2385 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2385 Nitrogen dioxide analyzer. (a) Identification. The nitrogen dioxide analyzer is a device intended to measure the concentration of...

  7. 21 CFR 868.2385 - Nitrogen dioxide analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nitrogen dioxide analyzer. 868.2385 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2385 Nitrogen dioxide analyzer. (a) Identification. The nitrogen dioxide analyzer is a device intended to measure the concentration of...

  8. 21 CFR 868.2385 - Nitrogen dioxide analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrogen dioxide analyzer. 868.2385 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2385 Nitrogen dioxide analyzer. (a) Identification. The nitrogen dioxide analyzer is a device intended to measure the concentration of...

  9. Vapor pressures and calculated heats of vaporization of concentrated nitric acid solutions in the composition range 71 to 89 percent nitrogen dioxide, 1 to 10 percent water, and in the temperature range 10 to 60 degrees C

    NASA Technical Reports Server (NTRS)

    Mckeown, A B; Belles, Frank E

    1954-01-01

    Total vapor pressures were measured for 16 acid mixtures of the ternary system nitric acid, nitrogen dioxide, and water within the temperature range 10 degrees to 60 degrees Celsius, and with the composition range 71 to 89 weight percent nitric acid, 7 to 20 weight percent nitrogen dioxide, and 1 to 10 weight percent water. Heats of vaporization were calculated from the vapor pressure measurements for each sample for the temperatures 25, 40, and 60 degrees Celsius. The ullage of the apparatus used for the measurements was 0.46. Ternary diagrams showing isobars as a function of composition of the system were constructed from experimental and interpolated data for the temperatures 25, 40, 45, and 60 degrees C and are presented herein.

  10. Comparison of Satellite Observations of Nitrogen Dioxide to Surface Monitor Nitrogen Dioxide Concentration

    NASA Technical Reports Server (NTRS)

    Kleb, Mary M.; Pippin, Margaret R.; Pierce, R. Bradley; Neil, Doreen O.; Lingenfelser, Gretchen; Szykman, James J.

    2006-01-01

    Nitrogen dioxide is one of the U. S. EPA s criteria pollutants, and one of the main ingredients needed for the production of ground-level ozone. Both ozone and nitrogen dioxide cause severe public health problems. Existing satellites have begun to produce observational data sets for nitrogen dioxide. Under NASAs Earth Science Applications Program, we examined the relationship between satellite observations and surface monitor observations of this air pollutant to examine if the satellite data can be used to facilitate a more capable and integrated observing network. This report provides a comparison of satellite tropospheric column nitrogen dioxide to surface monitor nitrogen dioxide concentration for the period from September 1996 through August 1997 at more than 300 individual locations in the continental US. We found that the spatial resolution and observation time of the satellite did not capture the variability of this pollutant as measured at ground level. The tools and processes developed to conduct this study will be applied to the analysis of advanced satellite observations. One advanced instrument has significantly better spatial resolution than the measurements studied here and operates with an afternoon overpass time, providing a more representative distribution for once-per-day sampling of this photochemically active atmospheric constituent.

  11. 40 CFR 52.1576 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52... strategy: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16346), are not met since the plan does not provide for the degree of nitrogen oxides emission...

  12. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan (SIP) codified at 40 CFR 52.1870(c)(128) is satisfied by Ohio's November 26, 2003, submittal of the... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide....

  13. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan (SIP) codified at 40 CFR 52.1870(c)(128) is satisfied by Ohio's November 26, 2003, submittal of the... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide....

  14. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan (SIP) codified at 40 CFR 52.1870(c)(128) is satisfied by Ohio's November 26, 2003, submittal of the... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide....

  15. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan (SIP) codified at 40 CFR 52.1870(c)(128) is satisfied by Ohio's November 26, 2003, submittal of the... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide....

  16. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan (SIP) codified at 40 CFR 52.1870(c)(128) is satisfied by Ohio's November 26, 2003, submittal of the... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide....

  17. Nitrogen dioxide absorption in aqueous sodium sulfite

    NASA Astrophysics Data System (ADS)

    Shen, Chen Hua

    The Clean Air Act of 1990 requires additional reduction of acid gases, sulfur dioxide, and nitrogen oxides released into the atmosphere from coal-fired electric power plants. In the case of older existing power plants, a possible retrofit strategy is to oxidize nitric oxide (NO, the major constituent of NOsbX in flue gas) to nitrogen dioxide (NOsb2) by the addition of methanol or other hydrocarbons into the duct at an optimum temperature regime. NOsb2 can then be removed by either modifying existing SOsb2 control equipment or by adding a limestone (CaCOsb3) slurry scrubbing process. Limestone reacts with SOsb2 to from CaSOsb3, and the free sulfite (SO{sb3sp{=}}) in the solution is reactive toward NOsb2. The focus of this research is to study the reaction between NOsb2 and aqueous sulfite at elevated temperature and in the presence of gas phase Osb2. The removal of NOsb2 by limestone slurry scrubbing involves the reaction between NOsb2 and SO{sb3sp{=}}, bisulfite (HSO{sb3sp{-}}) and water. The reactions between NOsb2 and SO{sb3sp{=}}/HSO{sb3sp{-}} are first order in both reactants, while the NOsb2-water reaction is second order in NOsb2 concentration. The rate constants of the above reactions and the NOsb2-thiosulfate (Ssb2O{sb3sp{=}}) reaction were determined at 55sp°C. SO{sb3sp{=}} was found to be the most reactive toward NOsb2, while the contribution of chemical reaction still dominated in the absorption of NOsb2 into water. The effect of gas phase SOsb2 and Osb2, and liquid phase additives such as Ssb2O{sb3sp{=}}, Casp{++}, Mgsp{++}, and Clsp{-} on NOsb2 absorption was also investigated. The absorption of NOsb2 catalyzes free radical reactions that lead to sulfite oxidation. A semi-empirical model was proposed to relate the rate of sulfite oxidation to the rate of NOsb2 absorption. Thiosulfate inhibits sulfite oxidation by providing an alternative route for the termination of the free radical reactions, and a fundamental model was derived to quantify the effect

  18. Nitrogen dioxide reducing ascorbic acid technologies in the ventilator circuit leads to uniform NO concentration during inspiration.

    PubMed

    Pezone, Matthew J; Wakim, Matthew G; Denton, Ryan J; Gamero, Lucas G; Roscigno, Robert F; Gilbert, Richard J; Lovich, Mark A

    2016-08-31

    Conventional inhaled NO systems deliver NO by synchronized injection or continuous NO flow in the ventilator circuitry. Such methods can lead to variable concentrations during inspiration that may differ from desired dosing. NO concentrations in these systems are generally monitored through electrochemical methods that are too slow to capture this nuance and potential dosing error. A novel technology that reduces NO2 into NO via low-resistance ascorbic-acid cartridges just prior to inhalation has recently been described. The gas volume of these cartridges may enhance gas mixing and reduce dosing inconsistency throughout inhalation. The impact of the ascorbic-acid cartridge technology on NO concentration during inspiration was characterized through rapid chemiluminescence detection during volume control ventilation, pressure control ventilation, synchronized intermittent mandatory ventilation and continuous positive airway pressure using an in vitro lung model configured to simulate the complete uptake of NO. Two ascorbic acid cartridges in series provided uniform and consistent dosing during inspiration during all modes of ventilation. The use of one cartridge showed variable inspiratory concentration of NO at the largest tidal volumes, whereas the use of no ascorbic acid cartridge led to highly inconsistent NO inspiratory waveforms. The use of ascorbic acid cartridges also decreased breath-to-breath variation in SIMV and CPAP ventilation. The ascorbic-acid cartridges, which are designed to convert NO2 (either as substrate or resulting from NO oxidation during injection) into NO, also provide the benefit of minimizing the variation of inhaled NO concentration during inspiration. It is expected that the implementation of this method will lead to more consistent and predictable dosing.

  19. Nitrogen dioxide reducing ascorbic acid technologies in the ventilator circuit leads to uniform NO concentration during inspiration.

    PubMed

    Pezone, Matthew J; Wakim, Matthew G; Denton, Ryan J; Gamero, Lucas G; Roscigno, Robert F; Gilbert, Richard J; Lovich, Mark A

    2016-08-31

    Conventional inhaled NO systems deliver NO by synchronized injection or continuous NO flow in the ventilator circuitry. Such methods can lead to variable concentrations during inspiration that may differ from desired dosing. NO concentrations in these systems are generally monitored through electrochemical methods that are too slow to capture this nuance and potential dosing error. A novel technology that reduces NO2 into NO via low-resistance ascorbic-acid cartridges just prior to inhalation has recently been described. The gas volume of these cartridges may enhance gas mixing and reduce dosing inconsistency throughout inhalation. The impact of the ascorbic-acid cartridge technology on NO concentration during inspiration was characterized through rapid chemiluminescence detection during volume control ventilation, pressure control ventilation, synchronized intermittent mandatory ventilation and continuous positive airway pressure using an in vitro lung model configured to simulate the complete uptake of NO. Two ascorbic acid cartridges in series provided uniform and consistent dosing during inspiration during all modes of ventilation. The use of one cartridge showed variable inspiratory concentration of NO at the largest tidal volumes, whereas the use of no ascorbic acid cartridge led to highly inconsistent NO inspiratory waveforms. The use of ascorbic acid cartridges also decreased breath-to-breath variation in SIMV and CPAP ventilation. The ascorbic-acid cartridges, which are designed to convert NO2 (either as substrate or resulting from NO oxidation during injection) into NO, also provide the benefit of minimizing the variation of inhaled NO concentration during inspiration. It is expected that the implementation of this method will lead to more consistent and predictable dosing. PMID:27264784

  20. Nitrogen dioxide and respiratory illness in children. Part II: Assessment of exposure to nitrogen dioxide.

    PubMed

    Lambert, W E; Samet, J M; Hunt, W C; Skipper, B J; Schwab, M; Spengler, J D

    1993-06-01

    Repeated measurements of nitrogen dioxide were obtained from 1988 to 1991 in the homes of 1,205 infants living in Albuquerque, NM. Passive diffusion samplers were used to obtain a series of two-week integrated measurements from the home of each infant for use in a cohort study of the relation of residential exposure to nitrogen dioxide and respiratory illnesses. Information on stove use and time spent inside the residence was collected at two-week and two-month intervals, respectively. During the winter, in the bedrooms of homes with gas cooking stoves, mean nitrogen dioxide concentrations were 21 parts per billion (ppb); mean concentrations in the living room and kitchen were 29 ppb and 34 ppb, respectively. In homes with electric cooking stoves, the mean bedroom concentration was 7 ppb during the winter. Lower indoor concentrations were observed during the summer in homes with both gas and electric stoves. On average, infants spent approximately 12.3 hours per day in their bedrooms, 7.3 hours in the living rooms, 35 minutes in the kitchens, and 3.8 hours out of their homes. (As a condition of participation, none of the infants spent more than 20 hours per week in day care outside of their homes). The mean time infants spent in the kitchen during cooking was approximately nine minutes per day. We tested whether exposures of infants living in homes with gas stoves could be reasonably estimated by measurements in the bedroom in comparison with time-weighted average concentrations based on time-activity data and simultaneous nitrogen dioxide measurements in the kitchen, living room, and bedroom. In 1,937 two-week intervals from 587 infants, 90% of time-weighted exposure (on the three-level classification used in this study) estimates were in agreement with estimates based on bedroom concentrations alone. The agreement of the time-weighted nitrogen dioxide exposure estimates with the bedroom concentrations is attributed to limited amounts of cooking stove use (the

  1. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... August 10, 1979, is disapproved because it is inconsistent with 40 CFR Subpart G, Control strategy... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  2. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... August 10, 1979, is disapproved because it is inconsistent with 40 CFR Subpart G, Control strategy... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  3. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... August 10, 1979, is disapproved because it is inconsistent with 40 CFR Subpart G, Control strategy... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  4. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... August 10, 1979, is disapproved because it is inconsistent with 40 CFR Subpart G, Control strategy... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  5. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... August 10, 1979, is disapproved because it is inconsistent with 40 CFR Subpart G, Control strategy... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  6. Does nitrogen dioxide exposure increase airways responsiveness

    SciTech Connect

    Folinsbee, L.J.

    1992-01-01

    A number of reports have suggested that exposure to nitrogen dioxide (NO2) may cause increased airways responsiveness (AR). Twenty studies of asthmatics and five studies of healthy subjects exposed to NO[sub 2] were used to test the hypothesis using a simple method of meta-analysis. Individual data were obtained for the above studies and the direction of change in AR was determined for each subject. Only studies with available individual data were used. Subjects from these studies whose directional change in AR could not be determined were excluded. The fraction of positive responses (i.e. increased AR) was determined for all subjects within a group and tested for significance using a sign test. Data were also grouped according to NO[sub 2] concentration and by whether the exposure included exercise.

  7. The development of a nitrogen dioxide sonde

    NASA Astrophysics Data System (ADS)

    Sluis, W. W.; Allaart, M. A. F.; Piters, A. J. M.; Gast, L. F. L.

    2010-07-01

    A growing number of space-borne instruments measures nitrogen dioxide (NO2) concentrations in the troposphere, but validation of these instruments is hampered by lack of ground-based and in-situ profile measurements. The Royal Netherlands Meteorological Institute (KNMI) has developed a working NO2 sonde. The sonde is attached to a small meteorological balloon and measures a tropospheric NO2 profile. The NO2 sonde has a vertical resolution of 5 m, and a measurement range between 1 and 100 ppbv. The instrument is light in weight (±700 g), cheap (disposable), energy efficient and not harmful to the environment or the person who finds the package after use. The sonde uses the chemiluminescent reaction of NO2 in an aqueous luminol solution. The NO2-luminol reaction produces faint blue/purple light (at about 425 nm), which is detected by an array of silicon photodiodes. The luminol solution is optimised to be specific to NO2. An on-ground comparison with measurements from a Photolytic Analyzer of RIVM shows that both instruments measure similar NO2 variations in ambient air. During the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI) in June/July 2009 six vertical profiles of NO2 from the ground to 5 km altitude were measured, which clearly show that the largest amount of NO2 is measured in the boundary layer. The measured boundary layer heights of the NO2 sonde are in good agreement with boundary layer heights determined by a LD40 Ceilometer at Cabauw.

  8. The development of a nitrogen dioxide sonde

    NASA Astrophysics Data System (ADS)

    Sluis, W. W.; Allaart, M. A. F.; Piters, A. J. M.; Gast, L. F. L.

    2010-12-01

    A growing number of space-borne instruments measures nitrogen dioxide (NO2) concentrations in the troposphere, but validation of these instruments is hampered by the lack of ground-based and in situ profile measurements. The Royal Netherlands Meteorological Institute (KNMI) has developed a working NO2 sonde. The sonde is attached to a small meteorological balloon and measures a tropospheric NO2 profile. The NO2 sonde has a vertical resolution of 5 m and a measurement range between 1 and 100 ppbv. The instrument is light in weight (0.7 kg), cheap (disposable), energy efficient and not harmful to the environment or the person who finds the package after use. The sonde uses the chemiluminescent reaction of NO2 in an aqueous luminol solution. The NO2-luminol reaction produces faint blue/purple light (at about 425 nm), which is detected by an array of silicon photodiodes. The luminol solution is optimised to be specific to NO2. An on-ground comparison with measurements from a Photolytic Analyser of The National Institute for Public Health and the Environment (RIVM) shows that both instruments measure similar NO2 variations in ambient air. During the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring instruments (CINDI) in June/July 2009, six vertical profiles of NO2 from the ground to a 5 km altitude were measured, which clearly show that the largest amount of NO2 is measured in the boundary layer. The measured boundary layer heights of the NO2 sonde are in good agreement with boundary layer heights determined by a LD40 Ceilometer at Cabauw.

  9. Stratospheric nitrogen dioxide in the vicinity of Soufriere, St. Vincent

    NASA Technical Reports Server (NTRS)

    Romick, G. J.; Murcray, D. G.; Williams, W. J.

    1982-01-01

    In April 1979, measurements of nitrogen dioxide in the upper atmosphere were made near Soufriere Volcano by twilight optical-absorption techniques. The derived value of 5 x 10 to the 15th molecules per square centimeter column implies an enhancement of 25 percent over earlier abundances measured in the same latitudinal regions. This enhancement may represent the normal stratospheric variability of nitrogen dioxide in the equatorial region, but in any case may be considered an upper limit to the volcano's effect on the total nitrogen dioxide abundance.

  10. Nitrogen dioxide and respiratory illnesses in infants

    SciTech Connect

    Samet, J.M.; Lambert, W.E.; Skipper, B.J.; Cushing, A.H.; Hunt, W.C.; Young, S.A.; McLaren, L.C.; Schwab, M.; Spengler, J.D. )

    1993-11-01

    Nitrogen dioxide is an oxidant gas that contaminates outdoor air and indoor air in homes with unvented gas appliances. A prospective cohort study was carried out to test the hypothesis that residential exposure to NO2 increases incidence and severity of respiratory illnesses during the first 18 months of life. A cohort of 1,205 healthy infants from homes without smokers was enrolled. The daily occurrence of respiratory symptoms and illnesses was reported by the mothers every 2 wk. Illnesses with wheezing or wet cough were classified as lower respiratory tract. Indoor NO2 concentrations were serially measured with passive samplers place in the subjects' bedrooms. In stratified analyses, illness incidence rates did not consistently increase with exposure to NO2 or stove type. In multivariate analyses that adjusted for potential confounding factors, odds ratios were not significantly elevated for current or lagged NO2 exposures, or stove type. Illness duration, a measure of illness severity, was not associated with NO2 exposure. The findings can be extended to homes with gas stoves in regions of the United States where the outdoor air is not heavily polluted by NO2.

  11. Nitrogen dioxide and respiratory illnesses in infants.

    PubMed

    Samet, J M; Lambert, W E; Skipper, B J; Cushing, A H; Hunt, W C; Young, S A; McLaren, L C; Schwab, M; Spengler, J D

    1993-11-01

    Nitrogen dioxide is an oxidant gas that contaminates outdoor air and indoor air in homes with unvented gas appliances. A prospective cohort study was carried out to test the hypothesis that residential exposure to NO2 increases incidence and severity of respiratory illnesses during the first 18 months of life. A cohort of 1,205 healthy infants from homes without smokers was enrolled. The daily occurrence of respiratory symptoms and illnesses was reported by the mothers every 2 wk. Illnesses with wheezing or wet cough were classified as lower respiratory tract. Indoor NO2 concentrations were serially measured with passive samplers place in the subjects' bedrooms. In stratified analyses, illness incidence rates did not consistently increase with exposure to NO2 or stove type. In multivariate analyses that adjusted for potential confounding factors, odds ratios were not significantly elevated for current or lagged NO2 exposures, or stove type. Illness duration, a measure of illness severity, was not associated with NO2 exposure. The findings can be extended to homes with gas stoves in regions of the United States where the outdoor air is not heavily polluted by NO2.

  12. SAGE observations of stratospheric nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Chu, W. P.; Mccormick, M. P.

    1986-01-01

    The global distribution of nitrogen dioxide in the middle to upper stratosphere (25-45 km altitude) for the period February 1979 to November 1981 has been determined from observations of attenuated solar radiation in the visible region 0.385-0.45 micron by the Stratospheric Aerosol and Gas Experiment (SAGE) satellite instrument. The SAGE-derived NO2 vertical profiles compare well with observations by balloon- and aircraft-borne sensors. The global SAGE NO2 distributions generally show a maximum in mixing ratio of 8 parts per billion by volume at about 35 km altitude near the equatorial latitudes at local sunset. The location of the mixing ratio peak moves synchronously with the overhead sun for the four different seasons. High-latitude NO2 column content shows strong seasonal variation, with a maximum in local summer and a minimum in local winter. Selected data at high-latitude winter seasons are presented, suggesting that the large variation shown could be explained by the coupling of both dynamics and photochemistry of the NO(x) species. Finally, profiles of the ratio of sunset to sunrise NO2 mixing ratios, peaking at about a factor of two at 30 km, are shown.

  13. Determination of nitrogen dioxide with a chemiluminescent aerosol detector

    SciTech Connect

    Mikuska, P.; Vecera, Z.

    1992-09-15

    A modified detector is described for use in the determination of nitrogen dioxide via reaction with luminol. Chemiluminescence of the aerosol particles formed by crossed streams of the analyte and an alkaline luminol solution was observed by a photomultiplier.

  14. 49 CFR 173.336 - Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Nitrogen dioxide, liquefied, or dinitrogen....336 Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied. (a) Nitrogen dioxide, liquefied... with nitrogen dioxide. Each valve opening must be closed by a solid metal plug with tapered...

  15. 49 CFR 173.336 - Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Nitrogen dioxide, liquefied, or dinitrogen....336 Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied. (a) Nitrogen dioxide, liquefied... with nitrogen dioxide. Each valve opening must be closed by a solid metal plug with tapered...

  16. 49 CFR 173.336 - Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Nitrogen dioxide, liquefied, or dinitrogen....336 Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied. (a) Nitrogen dioxide, liquefied... with nitrogen dioxide. Each valve opening must be closed by a solid metal plug with tapered...

  17. 49 CFR 173.336 - Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Nitrogen dioxide, liquefied, or dinitrogen....336 Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied. (a) Nitrogen dioxide, liquefied... with nitrogen dioxide. Each valve opening must be closed by a solid metal plug with tapered...

  18. 49 CFR 173.336 - Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitrogen dioxide, liquefied, or dinitrogen....336 Nitrogen dioxide, liquefied, or dinitrogen tetroxide, liquefied. (a) Nitrogen dioxide, liquefied... with nitrogen dioxide. Each valve opening must be closed by a solid metal plug with tapered...

  19. Low Energy, Low Emissions: Sulfur Dioxide; Nitrogen Oxides, and Carbon Dioxide in Western Europe.

    ERIC Educational Resources Information Center

    Alcamo, Joseph; De Vries, Bert

    1992-01-01

    Links proposed low-energy scenarios for different Western European countries with the amount of pollutants that may result from these scenarios. Sulfur dioxide, nitrogen oxide, and carbon dioxide emissions are calculated for the 10 countries for which low-energy scenarios are available, resulting in reductions of 54%, 37%, and 40%, respectively.…

  20. Acid sorption regeneration process using carbon dioxide

    DOEpatents

    King, C. Judson; Husson, Scott M.

    2001-01-01

    Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

  1. Exploration of gas sensing possibilities with edge plane pyrolytic graphite electrodes: nitrogen dioxide detection.

    PubMed

    Banks, Craig E; Goodwin, Alexander; Heald, Charles G R; Compton, Richard G

    2005-03-01

    The voltammetric response of nitrogen dioxide in aqueous sulfuric acid using an edge plane pyrolytic graphite electrode has been explored and contrasted with that from basal plane pyrolytic graphite, glassy carbon or boron-doped diamond electrodes. Edge plane graphite electrode is found to produce an excellent voltammetric signal in comparison with other carbon-based electrodes exhibiting a well-defined analytically useful voltammetric redox couple in 2.5 M sulfuric acid which is absent on the alternative electrodes.

  2. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide. 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.728 Control strategy:...

  3. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.728 Control strategy:...

  4. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide. 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.728 Control strategy:...

  5. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide. 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.728 Control strategy:...

  6. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide. 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Illinois> § 52.728 Control strategy:...

  7. Ozone and nitrogen dioxide above the northern Tien Shan

    NASA Technical Reports Server (NTRS)

    Arefev, Vladimir N.; Volkovitsky, Oleg A.; Kamenogradsky, Nikita E.; Semyonov, Vladimir K.; Sinyakov, Valery P.

    1994-01-01

    The results of systematic perennial measurements of the total ozone (since 1979) and nitrogen dioxide column (since 1983) in the atmosphere in the European-Asian continent center above the mountainmass of the Tien Shan are given. This region is distinguished by a great number of sunny days during a year. The observation station is at the Northern shore of Issyk Kul Lake (42.56 N 77.04 E 1650 m above the sea level). The measurement results are presented as the monthly averaged atmospheric total ozone and NO2 stratospheric column abundances (morning and evening). The peculiarities of seasonal variations of ozone and nitrogen dioxide atmospheric contents, their regular variances with a quasi-biennial cycles and trends have been noticed. Irregular variances of ozone and nitrogen dioxide atmospheric contents, i.e. their positive and negative anomalies in the monthly averaged contents relative to the perennial averaged monthly means, have been analyzed. The synchronous and opposite in phase anomalies in variations of ozone and nitrogen dioxide atmospheric contents were explained by the transport and zonal circulation in the stratosphere (Kamenogradsky et al., 1990).

  8. Effect of nitrogen dioxide on Swiss albino mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Machado, A. M.

    1977-01-01

    Times to incapacitation and death and LC50 values were determined for male Swiss albino mice exposed to different concentrations of nitrogen dioxide in a 4.2 liter hemispherical chamber. The LC50 for a 10 minute exposure was about 1000 ppm NO2.

  9. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected source or nitrogen oxide occur at an affected unit during any year, the owners and operators...

  10. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected source or nitrogen oxide occur at an affected unit during any year, the owners and operators...

  11. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected source or nitrogen oxide occur at an affected unit during any year, the owners and operators...

  12. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected source or nitrogen oxide occur at an affected unit during any year, the owners and operators...

  13. Chronic effects of nitrogen dioxide on cilia in hamster bronchioles.

    PubMed

    Heller, R F; Gordon, R E

    1986-01-01

    Nitrogen dioxide has been shown to have a deleterious effect on the structure and function of respiratory cilia. This study focuses on both the alterations of cilia morphology, and the ciliated cell response induced by nitrogen dioxide, in order to determine the mechanism(s) leading to ciliary dysfunction. Ciliated cells of the respiratory airways of hamsters, exposed to 30 ppm nitrogen dioxide for 5 months, 7 days/week, 22 hours/day, were examined ultrastructurally using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) of thin sections, freeze-fracture replicas, and thin sections of tissues treated with cationized ferritin. SEM and TEM preparations appeared to show a generalized reduction in number and length of cilia. It was common to see basal bodies with no ciliary shaft and many cilia at different stages of growth. It was also apparent that the cilia were most fragile just below the ciliary necklaces. After breakage, the plasma membranes of the remaining ciliary stubs covered the exposed basal bodies. During the early stages of ciliary regeneration, freeze fracture replicas showed the emergence of membrane particles which appeared to correlate with cationized ferritin binding sites. As the cilia increased in length, the particles assembled into a necklace-like arrangement, varying in ring number and particle distribution as compared to the 5 to 7 well organized rings observed in controls. In corresponding thin sections, cationized ferritin appeared bound to sites in the region of the ciliary necklace particles. As the cilia developed further, the cationic ferritin binding at these sites diminished. This data suggests that nitrogen dioxide had an affect on the plasma membranes of ciliated cells. One of the major sites affected by the nitrogen dioxide was the ciliary necklace region. Exposure to nitrogen dioxide appeared to lead to increased ciliary fragility, stunted ciliary growth, and loss of ciliary motility. The rings of ciliary

  14. Solubility of Sulfur Dioxide in Sulfuric Acid

    NASA Technical Reports Server (NTRS)

    Chang, K. K.; Compton, L. E.; Lawson, D. D.

    1982-01-01

    The solubility of sulfur dioxide in 50% (wt./wt.) sulfuric acid was evaluated by regular solution theory, and the results verified by experimental measurements in the temperature range of 25 C to 70 C at pressures of 60 to 200 PSIA. The percent (wt./wt.) of sulfur dioxide in 50% (wt./wt.) sulfuric acid is given by the equation %SO2 = 2.2350 + 0.0903P - 0.00026P 10 to the 2nd power with P in PSIA.

  15. Effect of carbon monoxide and nitrogen dioxide on ICR mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1977-01-01

    Times to incapacitation and death and LC(50) values were determined for male ICR mice exposed to different concentration of carbon monoxide for 30 min and of nitrogen dioxide for 10 min in a 4.2 liter hemispherical chamber. The data indicate that ICR mice are more resistant to these two toxicants than Swiss albino mice. The carbon monoxide LC(50) for a 30-min exposure was about 8,000 ppm for ICR mice compared to 3,570 ppm for Swiss albino mice. The nitrogen dioxide LC(50) for a 10-min exposure was above 2,000 ppm for ICR mice compared to about 1,000 ppm for Swiss albino mice.

  16. Uptake rate of nitrogen dioxide by potato plants

    SciTech Connect

    Sinn, J.P.; Pell, E.J.; Kabel, R.L.

    1984-06-01

    Greenhouse-grown potato plants were exposed to nitrogen dioxide in an exposure chamber to determine the rate of NO/sub 2/ uptake at concentrations from 228 to 817 ..mu..g/m/sup 3/ (0.12-0.43 ppm). Results show that a consistent increase in uptake rate accompanied an increase in NO/sub 2/ exposure concentrations. Exposure in the range of concentration had no significant effect on leaf diffusive resistance.

  17. Curing preceramic polymers by exposure to nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Rabe, James A. (Inventor); Lipowitz, Jonathan (Inventor); Lu, Paul P. (Inventor)

    1991-01-01

    A rapid method of infusibilizing (curing) preceramic polymers comprising treatment said polymers with gaseous nitrogen dioxide. The infusibilized polymers may be pyrolyzed to temperatures in excess of about 800.degree. C. to yield ceramic materials with low oxygen content and, thus, good thermal stability. The methods are especially useful for the production of ceramic fibers and, more specifically, to the on-line production of ceramic fibers.

  18. Control of Nitrogen Dioxide in Stack Emission by Reaction with Ammonia

    NASA Technical Reports Server (NTRS)

    Metzler, A. J.; Stevenson, E. F.

    1970-01-01

    The development of an acid base gas-phase reaction system which utilizes anhydrous ammonia as the reactant to remove nitrogen dioxide from hydrazine-nitrogen tetroxide rocket combustion exhaust is reported. This reaction reduced NO2 levels in exhaust emissions so that the resulting stack emission is completely white instead of the earlier observed typical reddish-brown coloration. Preliminary analyses indicate the importance of reaction time and ammonia concentration on removal efficiency and elimination of the health hazard to individuals with respiratory problems.

  19. Effects of nitric oxide and nitrogen dioxide on bacterial growth.

    PubMed Central

    Mancinelli, R L; McKay, C P

    1983-01-01

    The effects of low concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) on actively dividing cultures of Staphylococcus aureus, Micrococcus luteus, Micrococcus roseus, Serratia marcescens, Bacillus subtilis, Bacillus circulans, Bacillus megaterium, and Bacillus cereus were studied. Fresh cultures of each organism were incubated for 24 h at 25 degrees C on both nutrient agar and mineral salts glucose agar plates under atmospheres containing various low concentrations of NO in air (0 to 1.9 ppm [0 to 2.0 micrograms/g of air]), NO2 in air (0 to 5.5 ppm [0 to 8.8 micrograms/g of air]), or NO and NO2 in air. Bacteria grown under air only were used as controls. After incubation, the colonies that developed on the plates were counted. None of the bacteria tested was affected by NO or NO2 at the indicated concentrations while growing on nutrient agar. Serratia marcescens, B. circulans, B. subtilis, B. megaterium, and B. cereus grown on mineral salts glucose agar were not significantly affected by NO or NO2. Low concentrations (0 to 1.9 ppm) of NO were bacteriostatic to log-phase cultures of M. roseus, M. luteus, and Staphylococcus aureus grown on mineral salts glucose agar. Bacteriostatic activity over a 24-h interval was maximal at an initial NO concentration of 1 ppm. Appreciable amounts of NO2 were produced in 24 h at initial NO concentrations greater than 1 ppm. These results suggest that NO2 may reduce the bacteriostatic activity of NO. Low concentrations (0 to 5.5 ppm) of NO2 in air did not affect any of the bacteria tested. At these low concentrations, NO affected bacterial growth, although NO2, NO2-, and NO3- did not. In addition, it was determined that the bacteriostatic activity observed in this study was not due to an increase in the acidity of the medium. PMID:6351744

  20. Rheological study of foam fracturing fluids using nitrogen and carbon dioxide

    SciTech Connect

    Reidenbach, V.G.; Harris, P.C.; Lee, Y.N.; Lord, D.L.

    1983-01-01

    Foams are being used in a number of Petroleum Industry applications which exploit their high viscosity and low liquid content. Some of the earliest applications for foam dealt with its use as a displacing agent in porous media and as a drilling fluid. Following these early applications, foam was introduced as a well-bore circulating fluid for clean-out and workover applications. In the mid-1970s, nitrogen based foams became popular for both hydraulic fracturing and fracture acidizing stimulation treatments. In the latter 1970s and early 1980s foamed cementing became a viable service with foamed gravel packing close behind. Most recently, carbon dioxide foams have been found to be exhibiting their usefulness in hydraulic fracturing stimulation. This study proposes models to describe both laminar and turbulent non-Newtonian flow of nitrogen and carbon dioxide based foams. These experimentally derived models should provide a means for predicting foam flow behavior in a number of industry applications. 35 references.

  1. Rheological study of foam fracturing fluids using nitrogen and carbon dioxide

    SciTech Connect

    Reidenbach, V.G.; Harris, P.C.; Lee, Y.N.; Lord, D.L.

    1983-10-01

    Foams are being used in a number of petroleum industry applications which exploit their high viscosity and low liquid content. Some of the earliest applications for foam dealt with its use as a displacing agent in porous media and as a drilling fluid. Following these early applications, foam was introduced as a wellbore circulating fluid for clean-out and workover applications. In the mid-1970's, nitrogen based foams became popular for both hydraulic fracturing and fracture acidizing stimulation treatments. In the latter 1970's and early 1980's foamed cementing became a viable service with foamed gravel packing close behind. Most recently, carbon dioxide foams have been found to be exhibiting their usefulness in hydraulic fracturing stimulation. In this paper, the authors propose models to describe both laminar and turbulent non-Newtonian flow of nitrogen and carbon dioxide based foams. These experimentally derived models should provide a means for predicting foam flow behavior in a number of industry applications.

  2. 40 CFR 52.230 - Control strategy and regulations: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Nitrogen dioxide. 52.230 Section 52.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Control strategy and regulations: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter... nitrogen oxides emission reduction attainable through application of reasonably available...

  3. 40 CFR 52.230 - Control strategy and regulations: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Nitrogen dioxide. 52.230 Section 52.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Control strategy and regulations: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter... nitrogen oxides emission reduction attainable through application of reasonably available...

  4. 40 CFR 52.230 - Control strategy and regulations: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Nitrogen dioxide. 52.230 Section 52.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Control strategy and regulations: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter... nitrogen oxides emission reduction attainable through application of reasonably available...

  5. 40 CFR 52.230 - Control strategy and regulations: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Nitrogen dioxide. 52.230 Section 52.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Control strategy and regulations: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter... nitrogen oxides emission reduction attainable through application of reasonably available...

  6. 40 CFR 52.230 - Control strategy and regulations: Nitrogen dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Nitrogen dioxide. 52.230 Section 52.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Control strategy and regulations: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter... nitrogen oxides emission reduction attainable through application of reasonably available...

  7. Evaluation of nitrogen dioxide scavengers during delivery of inhaled nitric oxide.

    PubMed

    Lindberg, L; Rydgren, G

    1998-09-01

    We have analysed the ability of three nitrogen dioxide absorbing materials (soda lime, noXon and zeolite) to act as nitrogen dioxide scavengers during delivery of inhaled nitric oxide. Different mixtures of gas were produced in a ventilator (Servo Ventilator 300) and passed through an inspiratory tube. Concentrations of nitrogen dioxide and nitric oxide were measured in the distal part of the tube, with and without the gas having passed through a canister containing the different filter materials. Our findings indicated that nitrogen dioxide was absorbed effectively by all filter materials but that there was re-formation of nitrogen dioxide from nitric oxide and oxygen in or immediately after the canister. This initial production of nitrogen dioxide was very rapid and could not be prevented by the use of scavengers. Thus soda lime and zeolite had no practical effect as scavengers in this delivery system, and the effect of noXon was very slight.

  8. Hydraulic studies of drilling microbores with supercritical steam, nitrogen and carbon dioxide

    DOE Data Explorer

    Ken Oglesby

    2010-01-01

    Hydraulic studies of drilling microbores at various depths and with various hole sizes, tubing, fluids and rates showed theoretical feasibility. WELLFLO SIMULATIONS REPORT STEP 4: DRILLING 10,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE STEP 5: DRILLING 20,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE STEP 6: DRILLING 30,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE Mehmet Karaaslan, MSI

  9. Recommendations for air quality standards for nitrogen dioxide and ozone.

    PubMed

    Lindvall, T

    1985-01-01

    The acute health effects of nitrogen dioxide and ozone critical to the general population are summarized. For long-term exposures to the former in the outdoor environment a six-month average limit value of 80 micrograms/m3 is recommended for the wintertime. When "new" residential areas are planned or when the limit value is used as an air quality standard for the nonindustrial indoor environment, the adequate six-months' average limit value for the winter would be 50 micrograms/m3. For short-term exposures to nitrogen dioxide outdoors a limit value of 320 micrograms/m3 (1-h average) is recommended, not to be exceeded more than 12 h per year, each time during a maximum of 2 h. This value should apply only to "old" residential areas in which nitrogen dioxide pollution cannot be reduced without large economical and practical consequences. The value 190 micrograms/m3 (1-h average), not to be exceeded more than 12 h per year, should apply to most residential areas, to recreational areas, and to all nonindustrial indoor environments. For short-term exposures to photochemical oxidants, as represented by ozone in nonindustrial outdoor environments, the acceptable short-term limit value should be 120 micrograms/m3 (1-h average), not to be exceeded more than 12 h per year. An additional 1-h outdoor ceiling value of 200 micrograms/m3 is recommended, not to be exceeded. For the nonindustrial indoor environment a 1-h ceiling value of 100 micrograms/m3 is recommended, not to be exceeded.

  10. Developmental and hematological responses to low level continuous exposure of nitrogen dioxide in mice

    NASA Technical Reports Server (NTRS)

    Singh, J.

    1977-01-01

    Young healthy mice were continuously exposed to 0ppm, 0.5ppm, 1.0ppm and 5ppm nitrogen dioxide gas for eight weeks. Nitrogen dioxide exposure for eight weeks decreased the average weight of mice, increased the average weight of lungs, heart, and brain and decreased the average weight of liver. Nitrogen dioxide exposure did not have any effects on the WBC and RBC in mice blood but it increased the HCT and HGB in mice blood. Nitrogen dioxide exposure increased the MCV and decreased the MCH and MCHC in mice blood.

  11. Nitrogen fixation rate and chlorophyll content of the lichen Peltigera canina exposed to sulfur dioxide

    SciTech Connect

    Henriksson, E.; Pearson, L.C.

    1981-01-01

    In general, the rate of nitrogen fixation decreased when the lichen Peltigera canina (L.) Willd. was exposed to sulfur dioxide gas at levels from 0.1 to 500 ppm; at 30 ppm, however, nitrogen fixation was stimulated. The chlorophyll content decreased as the level of sulfur dioxide increased.

  12. Remote sensing of ammonia, sulfur dioxide, and nitrogen dioxide emissions from cars and trucks

    NASA Astrophysics Data System (ADS)

    Burgard, Daniel Alexander

    This document describes the development of a remote sensor for mobile source ammonia (NH3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) based on an instrument previously developed at the University of Denver. Significant optical upgrades allow for the detection of three new species. Detection and quantification of NH3 and SO 2 use wavelengths deeper into the ultraviolet region than previously possible. Currently NH3 is quantified from three peaks at 209 nm, 213 nm, and 217 nm; SO2 from three peaks at 219 nm, 221 nm, and 222 nm; NO2 using the spectral window 430--446 nm. The instrument was demonstrated in the measurement of emissions from both gasoline and diesel light duty vehicles and heavy duty diesel trucks (HDDT). The remote sensor was used for over 20,000 measurements of NH3 and SO2 emissions from motor vehicles in Denver and Tulsa in the summer of 2005. Nitrogen dioxide emissions were measured at the Denver site only. For the first time, on-road vehicle NH3 and SO2 emission trends versus model year were observed. Ammonia is a larger percentage of the exhaust than previously predicted for newer vehicles and its production reaches a maximum with approximately the 1996 model year. NH3 is the first pollutant observed to have lower emissions from the oldest model year. Sulfur dioxide emissions decrease with newer model year vehicles. Nearly 1200 NH3, SO2, and NO2 emission measurements with valid vehicle identification numbers were collected from in-use HDDTs in Golden and Dumont, CO. The Dumont weigh station site allowed emissions to be correlated with gross vehicle weight. No trends were apparent. The Golden site allowed emissions to be correlated with odometer and a trend of increasing oxides of nitrogen (NOx) emissions was apparent even near one million miles, when some vehicles should show lower emissions due to engine rebuild and computer reflash. For the first time HDDT on-road NO x emissions were shown versus vehicle model year and found to reach a

  13. Response of radish to nitrogen dioxide, sulfur dioxide, and ozone, alone and in combination

    SciTech Connect

    Reinert, R.A.; Gray, T.N.

    1981-04-01

    Effects on radish (Raphanus sativus L.) cv. Cherry Belle of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and ozone (O/sub 3/) alone and in combination at 0.2 and 0.4 ppM of each pollutant were studied. There was no difference in foilage or root weight of radish between exposure durations of 3 to 6 hours, and no significant interaction of hours with air pollutant and concentration. Ozone reduced root dry weight more at 0.4 ppM than at 0.2 ppM. Sulfur dioxide depressed the root/shoot ratio at both 0.2 and 0.4 ppM; however, when NO/sub 2/ and SO/sub 2/ were both present there was synergistic depression of the root/shoot ratio at 0.4 ppM. The average O/sub 3/-induced reduction in root weight of radish (1.75 g fresh and 101 mg dry, per plant) was additive in the presence of NO/sub 2/ and SO/sub 2/. The weight of the root was reduced even though the foilage was the direct receptor of the pollutant stress.

  14. Responses of Tree Seedlings to a Changing Atmosphere: Effects of Carbon Dioxide, Nitrogen Dioxide, and Ozone

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; Sparks, J. P.

    2008-12-01

    Human activities have caused changes in the chemical composition of the atmosphere: the concentrations of carbon dioxide (CO2), nitrogen dioxide (NO2), and ozone (O3) have increased and are expected to continue increasing in the future. These gases have the potential to alter plant physiological processes, change growth rates, C:N, and carbon storage potential. The responses of tree seedlings to these changes will have a profound impact on the species composition and carbon storage potential of forests in the future. Others have found CO2 tends to increase plant growth and O3 to decrease it. NO2, if assimilated by plants, can be a source of nutrient nitrogen, but is also an oxidant with the potential to damage cell membranes and decrease growth. The objectives of this study were to determine the single and combined effects of CO2, NO2, and O3 on sugar maple, eastern hemlock, and two clones of trembling aspen. The trees were fumigated for two growing seasons with elevated (40ppb) or ambient NO2, elevated (560ppm) or ambient CO2, elevated (100 ppb 5 days/week) or ambient O3, and with or without additional soil nitrate (30 kg ha-1 yr-1) to simulate ecosystems with and without nitrogen limitation. We found that elevated CO2 increased total biomass of both maples and hemlocks. Further, the CO2 growth effect was most striking when combined with elevated O2; elevated CO2 eliminated the growth decrease induced by O3 especially when nitrogen was limited. Elevated NO2 had no effect on maple seedlings, but, similar to CO2, eliminated the decrease in growth under O3 on hemlock seedlings. The two aspen clones differed in their resistance to ozone. The non-resistant clone exhibited growth responses similar to maple. However, the resistant clone did not exhibit a growth response under any gas treatment regardless of soil nitrogen status. The variation in responses among species, within clones of the same species, and between fumigations was large in this study and suggests

  15. Long term changes of tropospheric Nitrogen Dioxide over Pakistan derived from Ozone Monitoring Instrument (OMI) during the time period of October 2004 to December 2014

    NASA Astrophysics Data System (ADS)

    Murtaza, Rabbia; Fahim Khokhar, Muhammad

    2016-07-01

    Urban air pollution is causing huge number of diseases and deaths annually. Nitrogen dioxide is an important component of urban air pollution and a precursor to particulate matter, ground level ozone, and acid rain. The satellite based measurements of nitrogen dioxide from Ozone Monitoring Instrument (OMI) can help in analyzing spatio temporal variability in ground level concentrations within a large urban area. In this study, the spatial and temporal distributions of tropospheric nitrogen dioxide Vertical Column Densities (VCDs) over Pakistan are presented from 2004 to 2014. The results showed that the winter season is having high nitrogen dioxide levels as compared to summers. The increase can be attributed to the anthropogenic activities especially thermal power generation and traffic count. Punjab is one of the major provinces with high nitrogen dioxide levels followed by Sindh, Khyber Pakhtunkhwa and Balochistan. Six hotspots have been examined in the present study such as Lahore, Islamabad, Karachi, Faisalabad, Okara and Multan. Emissions of nitrogen compounds from thermal power plants and transportation sector represent a significant fraction of the total nitrogen dioxide emissions to the atmosphere.

  16. Association of indoor nitrogen dioxide with respiratory symptoms and pulmonary function in children

    SciTech Connect

    Neas, L.M.; Dockery, D.W.; Ware, J.H.; Spengler, J.D.; Speizer, F.E.; Ferris, B.G. Jr. )

    1991-07-15

    The effect of indoor nitrogen dioxide on the cumulative incidence of respiratory symptoms and pulmonary function level was studied in a cohort of 1,567 white children aged 7-11 years examined in six US cities from 1983 through 1988. Week-long measurements of nitrogen dioxide were obtained at three indoor locations over 2 consecutive weeks in both the winter and the summer months. The household annual average nitrogen dioxide concentration was modeled as a continuous variable and as four ordered categories. Multiple logistic regression analysis of symptom reports from a questionnaire administered after indoor monitoring showed that a 15-ppb increase in the household annual nitrogen dioxide mean was associated with an increased cumulative incidence of lower respiratory symptoms (odds ratio (OR) = 1.4, 95% confidence interval (95% Cl) 1.1-1.7). The response variable indicated the report of one or more of the following symptoms: attacks of shortness of breath with wheeze, chronic wheeze, chronic cough, chronic phlegm, or bronchitis. Girls showed a stronger association (OR = 1.7, 95% Cl 1.3-2.2) than did boys (OR = 1.2, 95% Cl 0.9-1.5). An analysis of pulmonary function measurements showed no consistent effect of nitrogen dioxide. These results are consistent with earlier reports based on categorical indicators of household nitrogen dioxide sources and provide a more specific association with nitrogen dioxide as measured in children's homes.

  17. Reduction in nitrogen dioxide concentration by soda lime preparations during simulated nitric oxide inhalation.

    PubMed

    Weimann, J; Hagenah, J U; Motsch, J

    1997-11-01

    Nitrogen dioxide is formed during delivery of inhaled nitric oxide for the treatment of patients with pulmonary hypertension. Soda lime has been shown to absorb nitrogen dioxide. We tested three different commercially available soda lime preparations (Sodasorb, Drägersorb 800 and Sofnolime) for their efficacy in absorbing nitrogen dioxide and nitric oxide during simulated nitric oxide inhalation. All soda lime preparation absorbed nitrogen dioxide (15%, 24% and 34%, respectively). To test if this difference could be attributed to the potassium hydroxide (KOH) content of the different preparations, two other preparations with a higher (3.0% and 7.3% w/w, respectively) KOH content were tested and we found an increase in nitrogen dioxide removal up to 47% and 46%, respectively. We conclude that soda lime absorbed nitrogen dioxide during nitric oxide inhalation. This effect seemed to be moderate under simulated clinical conditions, but increased using soda lime with a higher KOH content. Nevertheless, we recommend continuous monitoring of inspired nitrogen dioxide concentration during clinical inhalation of nitric oxide.

  18. Nitrogen dioxide and respiratory illness in children. Part I: Health outcomes.

    PubMed

    Samet, J M; Lambert, W E; Skipper, B J; Cushing, A H; Hunt, W C; Young, S A; McLaren, L C; Schwab, M; Spengler, J D

    1993-06-01

    We have carried out a prospective cohort study to test the hypothesis that exposure to nitrogen dioxide increases the incidence and severity of respiratory infections during the first 18 months of life. Between January 1988 and June 1990, 1,315 infants were enrolled into the study at birth and followed with prospective surveillance for the occurrence of respiratory infections and monitoring of nitrogen dioxide concentrations in their homes. The subjects were healthy infants from homes without smokers; they were selected with stratification by type of cooking stove at a ratio of four to one for gas and electric stoves. Illness experience was monitored by a daily diary of symptoms completed by the mother and a telephone interview conducted every two weeks. Illnesses with wheezing or wet cough were classified as involving the lower respiratory tract; all other respiratory illnesses were designated as involving the upper respiratory tract. Exposure to nitrogen dioxide was estimated by two-week average concentrations measured in the subjects' bedrooms with passive samplers. This analysis is limited to the 1,205 subjects completing at least one month of observation; of these, 823 completed the full protocol, contributing 82.8% of the total number of days during which the subjects were under observation. Incidence rates for all respiratory illnesses, all upper respiratory illness, all lower respiratory illnesses, and lower respiratory illness further divided into those with any wheezing, or wet cough without wheezing, were examined within strata of nitrogen dioxide exposure at the time of the illness, nitrogen dioxide exposure during the prior month, and type of cooking stove. Consistent trends of increasing illness incidence rates with increasing exposure to nitrogen dioxide were not evident for either the lagged or unlagged exposure variables. The effect of nitrogen dioxide exposure on illness occurrence during at-risk intervals of two weeks' duration was examined using

  19. Synergistic effects of nitrogen dioxide and carbon dioxide following acute inhalation exposures in rats

    SciTech Connect

    Levin, B.C.; Paabo, M.; Highbarger, L.; Eller, N.

    1989-05-01

    All fires occurring in air produce carbon dioxide (CO{sub 2}). Fire involving nitrogen-containing products will also generate nitrogen dioxide (NO{sub 2}), a pulmonary irritant. In Fischer 344 male rats, the LC50 (30 minute exposure plus 14 day post-exposure observation period) for NO{sub 2} was 200 ppm (with 95% confidence limits of 43 to 51%); whereas, the LC50 for NO{sub 2} in the presence of 5% CO{sub 2} was 90 ppm (with 90% confidence limits ranging from 70-120 ppm). Exposure to NO{sub 2} increased the methemoglobin (MetHb) levels in the arterial blood. At the end of the 30 minute exposures, the MetHb levels were 2-3 times higher in the animals exposed to the combination of NO{sub 2} (200 ppm) and CO{sub 2} (5%) than in those exposed to NO{sub 2} only. Deaths from NO{sub 2} were all post-exposure and occurred earlier in the presence of NO{sub 2} plus 5% CO{sub 2} than in the absence of the CO{sub 2}. The time of death was concentration-dependent when both gases were present. At death, evidence of hemorrage and extensive edema was observed in the lungs. The mean lung wet weight/body weight ratio from rats exposed to 200 ppm NO{sub 2} with and without 5% CO{sub 2} was 3-4 times that of non-exposed rats. More edema was noted with NO2 and CO{sub 2} than with NO{sub 2} alone.

  20. Analysis of Nitrogen Dioxide and Sulphur Dioxide in Lima, Peru: Trends and Seasonal Variations

    NASA Astrophysics Data System (ADS)

    Pacsi, S.; Rappenglueck, B.

    2007-12-01

    This research was carried out to show a general analysis of the monthly and yearly variation (1996-2002) and the tendency of the nitrogen dioxide (NO2) and sulfur dioxide (SO2) for the 5 stations of the air quality network of Lima. The SO2 and NO2 concentrations were measured by the Dirección General de Salud Ambiental (DIGESA), using the active sampling method and the chemical analysis has been determined by Turbidimetry and Colorimetry for the SO2 and NO2 respectively. The monthly average variation (1996-2001) of SO2 in the Lima Center station has a small annual range (32,4 mikrograms/m3) with maximum values in autumn (April) and minimum in winter (June). The NO2 presents a higher annual range (128,2 mikrograms/m3) and its minimum values occur in the summer and the maximum in spring. The annual averages analysis (2000-2002) of the air quality monitoring network of Lima shows that the SO2 and NO2 values are maximum in the Lima Center station and exceed the Peruvian air quality standard (ECAs) in 30% and 75% respectively. The yearly variation (1996-2001) in the Lima Center station show an increasing tendency in the SO2 (significant) and NO2 (not significant) values, which indicates the critical level of the air quality in Lima, therefore the implementation of the air pollution control programs is urgent.

  1. Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

    SciTech Connect

    Reinert, R.A.; Sanders, J.S.

    1982-02-01

    Radish and marigold plants were exposed to 0.3 ppM of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and /or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/ and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in the presence of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 2/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present. 8 references, 2 tables.

  2. Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

    SciTech Connect

    Reinert, R.A.; Sanders, J.S.

    1982-02-01

    Radish and marigold plants were exposed to 0.3 ppm of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and/or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in the presence of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 3/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present.

  3. Taxon-specific response of marine nitrogen fixers to elevated carbon dioxide concentrations

    NASA Astrophysics Data System (ADS)

    Hutchins, David A.; Fu, Fei-Xue; Webb, Eric A.; Walworth, Nathan; Tagliabue, Alessandro

    2013-09-01

    Much of the bioavailable nitrogen that supports open ocean food webs and biogeochemical cycles is fixed from the atmosphere by marine cyanobacteria of the genera Trichodesmium and Crocosphaera. In previous experiments carried out with a limited set of cyanobacterial isolates, rates of cyanobacterial nitrogen fixation were shown to increase with carbon dioxide concentrations. Here, we report results from a series of laboratory experiments in which we grew seven strains of Trichodesmium and Crocosphaera from the Atlantic and Pacific oceans under a wide range of carbon dioxide concentrations, and monitored rates of nitrogen fixation and growth. We document large, strain-specific differences in the relationship between nitrogen fixation and carbon dioxide concentration, suggesting that individual strains within each genus are adapted to grow and fix nitrogen at different concentrations of carbon dioxide. We apply kinetic constants from the individual carbon dioxide response curves to an illustrative biogeochemical model of the ocean in 2100, which suggests that strains adapted to high carbon dioxide concentrations could potentially be favoured in a future acidified ocean. We suggest that surface ocean carbon dioxide concentrations could constitute a previously unrecognized selective force that shapes the community composition and diversity of nitrogen-fixing cyanobacteria.

  4. Hemispherical Scanning Imaging DOAS: Resolving nitrogen dioxide in the urban environment

    NASA Astrophysics Data System (ADS)

    Leigh, R. J.; Graves, R. R.; Lawrence, J.; Faloon, K.; Monks, P. S.

    2012-12-01

    Imaging DOAS techniques have been used for nitrogen dioxide and sulfer dioxide for a number of years. This presentation describes a novel system which images concentrations of nitrogen dioxide by scanning an imaging spectrometer 360 degrees azimuthally, covering a region from 5 degrees below the horizon, to the zenith. The instrument has been built at the University of Leicester (UK), on optical designs by Surrey Satellite Technologies Ltd, and incorporates an Offner relay with Schwarzchild fore-optics, in a rotating mount. The spectrometer offers high fidelity spectroscopic retrievals of nitrogen dioxide as a result of a reliable Gaussian line shape, zero smile and low chromatic aberration. The full hemispherical scanning provides complete coverage of nitrogen dioxide concentrations above approximately 5 ppbv in urban environments. Through the use of multiple instruments, the three-dimensional structure of nitrogen dioxide can be sampled and tomographically reconstructed, providing valuable information on nitrogen dioxide emissions and downwind exposure, in addition to new understanding of boundary layer dynamics through the use of nitrogen dioxide as a tracer. Furthermore, certain aerosol information can be retrieved through absolute intensity measurements in each azimuthal direction supplemented by traditional techniques of O4 spectroscopy. Such measurements provide a new tool for boundary layer measurement and monitoring at a time when air quality implications on human health and climate are under significant scrutiny. This presentation will describe the instrument and tomographic potential of this technique. First measurements were taken as part of the international PEGASOS campaign in Bologna, Italy. Results from these measurements will be shown, including imaging of enhanced NO2 in the Bologna urban boundary layer during a severe thunderstorm. A Hemispherical Scanning Imaging DOAS instrument operating in Bologna, Italy in June 2012. Visible in the background

  5. Capillary gas chromatographic analysis of nitrogen dioxide and pans with luminol chemiluminescent detection.

    SciTech Connect

    Gaffney, J. S.; Bornick, R. M.; Chen, Y.-H.; Marley, N. A.; Environmental Research

    1998-01-01

    Peroxyacyl nitrates (PANs) and nitrogen dioxide are important atmospheric air pollutants in the troposphere. These atmospheric nitrogen species are strongly coupled chemically by a clearly temperature-dependent equilibrium in the troposphere. A chemical method that can measure both nitrogen dioxide and PANs rapidly and with sub-part-per-billion detection is described that is based upon a modified luminol detection system coupled to a capillary gas chromatographic column by using helium as a carrier. The system can readily separate and detect nitrogen dioxide, peroxyacetyl nitrate, peroxyproprionyl nitrate, and peroxybutyrl nitrate with detection limits in the low tens of parts per trillion with total analysis time of less than 1 min. Calibration of PAN by thermal decomposition to nitrogen dioxide is demonstrated with PAN detection sensitivities approximately 75% of the sensitivities observed for NO2 luminol detection by using helium as a carrier gas. The advantages of this method for simultaneous measurement of nitrogen dioxide and PANs over ozone chemiluminescent detection and electron capture detection are discussed, as well as potential applications of this method for heterogeneous surface chemistry studies of PANs and nitrogen dioxide and for tropospheric measurements.

  6. Classification of house characteristics based on indoor nitrogen dioxide concentrations

    SciTech Connect

    Lee, K.; Yanagisawa, Y.; Spengler, J.D.; Billick, I.H.

    1995-08-01

    House characteristics determining indoor nitrogen dioxide (NO{sub 2}) levels were extracted from a large scale field study in the Boston area. In this field study, indoor and outdoor NO{sub 2} levels and house characteristics were measured in three seasons: winter, summer, and fall. Data were analyzed by cross-table analysis to avoid problems of missing data. An attributable variable was selected when more than 90% of dwelling units with the particular variable had indoor to outdoor NO{sub 2} ratio (I/O) greater or less than unity. The dwelling units with electric stove had I/O less than unity. The dwelling units having a gas stove with a pilot light had kitchen NO{sub 2} levels higher than concurrently measured outdoor NO{sub 2} levels. The dwelling units with a gas stove having no pilot light had the I/O of around 1. Therefore, NO{sub 2} exposure groups in epidemiological studies should be determined by stove type and the presence of a pilot light, in order to reduce underestimation from exposure misclassification. 18 refs., 2 figs., 5 tabs.

  7. Home interventions are effective at decreasing indoor nitrogen dioxide concentrations

    PubMed Central

    Paulin, L. M.; Diette, G. B.; Scott, M.; McCormack, M. C.; Matsui, E. C.; Curtin-Brosnan, J.; Williams, D. L.; Kidd-Taylor, A.; Shea, M.; Breysse, P. N.; Hansel, N. N.

    2016-01-01

    Nitrogen dioxide (NO2), a by-product of combustion produced by indoor gas appliances such as cooking stoves, is associated with respiratory symptoms in those with obstructive airways disease. We conducted a three-armed randomized trial to evaluate the efficacy of interventions aimed at reducing indoor NO2 concentrations in homes with unvented gas stoves: (i) replacement of existing gas stove with electric stove; (ii) installation of ventilation hood over existing gas stove; and (iii) placement of air purifiers with high-efficiency particulate air (HEPA) and carbon filters. Home inspection and NO2 monitoring were conducted at 1 week pre-intervention and at 1 week and 3 months post-intervention. Stove replacement resulted in a 51% and 42% decrease in median NO2 concentration at 3 months of follow-up in the kitchen and bedroom, respectively (P = 0.01, P = 0.01); air purifier placement resulted in an immediate decrease in median NO2 concentration in the kitchen (27%, P < 0.01) and bedroom (22%, P = 0.02), but at 3 months, a significant reduction was seen only in the kitchen (20%, P = 0.05). NO2 concentrations in the kitchen and bedroom did not significantly change following ventilation hood installation. Replacing unvented gas stoves with electric stoves or placement of air purifiers with HEPA and carbon filters can decrease indoor NO2 concentrations in urban homes. PMID:24329966

  8. Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust.

    PubMed

    Zhou, Li; Wang, Weigang; Hou, Siqi; Tong, Shengrui; Ge, Maofa

    2015-12-01

    Mineral dust is one of the major aerosols in the atmosphere. To assess its impact on trace atmospheric gases, in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO2 on the surface of ambient Chinese dust over the temperature range from 258 to 313K. The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence. Similar to a previous study on NO2 uptake on mineral aerosols, the uptake coefficients are mainly on the order of 10(-6) for the Chinese dust, when BET areas are taken into account. HONO was observed as a product, and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied. The complete dataset from this study was compiled with previous literature determinations. Atmospheric implications of the heterogeneous reaction between NO2 and mineral dust are also discussed, in an effort to understand this important heterogeneous process.

  9. Peak exposures to nitrogen dioxide and study design to detect their acute health effects

    SciTech Connect

    Goldstein, I.F.; Andrews, L.R.

    1986-04-01

    Findings on continuous exposure to nitrogen dioxide by persons cooking a meal on a gas stove are presented. In addition, peak levels of NO/sub 2/ at different heights above the floor and at various distances from the stove while the range and oven are in operation are reported for 24 homes. A study design to detect the health effects of short-term exposures to high levels of nitrogen dioxide ranging from 0.20 ppm to over 1.5 ppm on pulmonary function and respiratory symptoms in asthmatic and non-asthmatic subjects is described. The continuous exposure to nitrogen dioxide of the study subjects before, during and after cooking a dinner on a gas stove is determined using a continuous nitrogen dioxide monitoring instrument. Lung-function tests are performed and symptom questionnaires are administered throughout the study period to assess both health effects and changes in pulmonary function associated with the above exposures.

  10. Infrared spectrum of the complex of formaldehyde with carbon dioxide in argon and nitrogen matrices

    NASA Technical Reports Server (NTRS)

    Van Der Zwet, G. P.; Allamandola, Louis J.; Baas, F.; Greenberg, J. M.

    1989-01-01

    The complex of formaldehyde with carbon dioxide has been studied by infrared spectroscopy in argon and nitrogen matrices. The shifts relative to the free species show that the complex is weak and similar in argon and nitrogen. The results give evidence for T-shaped complexes, which are isolated in several configurations. Some evidence is also presented which indicates that, in addition to the two well-known sites in argon, carbon dioxide can be trapped in a third site.

  11. The reaction of hydrogen peroxide with nitrogen dioxide and nitric oxide.

    NASA Technical Reports Server (NTRS)

    Gray, D.; Lissi, E.; Heicklen, J.

    1972-01-01

    The reactions were studied with the aid of a mass spectrometer. A pinhole bleed system provided continuous sampling of the gas mixture in the cell during the reaction. It was found that the homogeneous reactions of nitric oxide and nitrogen dioxide with hydrogen peroxide are too slow to be of any significance in the upper atmosphere. However, the heterogeneous reactions may be important in the conversion of nitric oxide to nitrogen dioxide in the case of polluted urban atmospheres.

  12. A Passive Sampler for Determination of Nitrogen Dioxide in Ambient Air

    ERIC Educational Resources Information Center

    Xiao, Dan; Lin, Lianzhi; Yuan, Hongyan; Choi, Martin M. F.; Chan, Winghong

    2005-01-01

    A passive sampler that provides a convenient, simple, and fast method for nitrogen dioxide determination is proposed. The experiment can be modified for determinations of other air pollutants like formaldehyde and sulfur dioxide for hands-on experience for students studying environmental pollution problems.

  13. Respiratory symptoms in children and indoor exposure to nitrogen dioxide and gas stoves.

    PubMed

    Garrett, M H; Hooper, M A; Hooper, B M; Abramson, M J

    1998-09-01

    Nitrogen dioxide levels were measured in 80 homes in the Latrobe Valley, Victoria, Australia, using passive samplers. Some 148 children between 7 and 14 yr of age were recruited as study participants, 53 of whom had asthma. Health outcomes for the children were studied using a respiratory questionnaire, skin prick tests, and peak flow measurements. Nitrogen dioxide concentrations were low, with an indoor median of 11.6 microgram/m3 (6.0 ppb), and a maximum of 246 microgram/m3 (128 ppb). Respiratory symptoms were more common in children exposed to a gas stove (odds ratio 2.3 [95% CI 1. 0-5.2], adjusted for parental allergy, parental asthma, and sex). Nitrogen dioxide exposure was a marginal risk factor for respiratory symptoms, with a dose-response association present (p = 0.09). Gas stove exposure was a significant risk factor for respiratory symptoms even after adjusting for nitrogen dioxide levels (odds ratio 2.2 [1.0-4.8]), suggesting an additional risk apart from the average nitrogen dioxide exposure associated with gas stove use. Atopic children tended to have a greater risk of respiratory symptoms compared with nonatopic children with exposure to gas stoves or nitrogen dioxide, but the difference was not significant.

  14. An Improved Retrieval of Tropospheric Nitrogen Dioxide from GOME

    NASA Technical Reports Server (NTRS)

    Martin, Randall V.; Chance, Kelly; Jacob, Daniel J.; Kurosu, Thomas P.; Spurr, Robert J. D.; Bucsela, Eric; Gleason, James F.; Palmer, Paul I.; Bey, Isabelle; Fiore, Arlene M.

    2002-01-01

    We present a retrieval of tropospheric nitrogen dioxide (NO2) columns from the Global Ozone Monitoring Experiment (GOME) satellite instrument that improves in several ways over previous retrievals, especially in the accounting of Rayleigh and cloud scattering. Slant columns, which are directly fitted without low-pass filtering or spectral smoothing, are corrected for an artificial offset likely induced by spectral structure on the diffuser plate of the GOME instrument. The stratospheric column is determined from NO2 columns over the remote Pacific Ocean to minimize contamination from tropospheric NO2. The air mass factor (AMF) used to convert slant columns to vertical columns is calculated from the integral of the relative vertical NO2 distribution from a global 3-D model of tropospheric chemistry driven by assimilated meteorological data (Global Earth Observing System (GEOS)-CHEM), weighted by altitude dependent scattering weights computed with a radiative transfer model (Linearized Discrete Ordinate Radiative Transfer), using local surface albedos determined from GOME observations at NO2 wavelengths. The AMF calculation accounts for cloud scattering using cloud fraction, cloud top pressure, and cloud optical thickness from a cloud retrieval algorithm (GOME Cloud Retrieval Algorithm). Over continental regions with high surface emissions, clouds decrease the AMT by 20- 30% relative to clear sky. GOME is almost twice as sensitive to tropospheric NO2 columns over ocean than over land. Comparison of the retrieved tropospheric NO2 columns for July 1996 with GEOS-CHEM values tests both the retrieval and the nitrogen oxide radical (NOx) emissions inventories used in GEOS-CHEM. Retrieved tropospheric NO2 columns over the United States, where NOx emissions are particularly well known, are within 18% of GEOS-CHEM columns and are strongly spatially correlated (r = 0.78, n = 288, p less than 0.005). Retrieved columns show more NO2 than GEOS-CHEM columns over the Transvaal

  15. Nitrogen dioxide exposure and development of pulmonary emphysema

    SciTech Connect

    Stavert, D.M.; Archuleta, D.C.; Holland, L.M.; Lehnert, B.E.

    1986-01-01

    Lungs of adult Fischer-344 rats were evaluated for emphysematous changes after (1) a single intratracheal instillation of elastase (E), (2) a 25-d exposure to 35 ppm nitrogen dioxide (NO/sub 2/), and (3) elastase instillation followed by 25-d exposure to 35 ppm NO/sub 2/ (E + NO/sub 2/). Residual volumes (RV) of the NO/sub 2/ and NS groups were virtually identical, whereas the RV of the E and E + NO/sub 2/ lungs were significantly greater than those of the NS and NO/sub 2/ lungs. Directionally similar changes in the excised lung volumes and total lung capacities were obtained with the E and E + NO/sub 2/ groups; NO/sub 2/ alone, however, did not alter these volumetric parameters. No differences in arterial blood gases and pH values, minute ventilation, or breathing frequencies were found among the experimental groups. The mean linear intercept values (MLI) obtained with the NS and NO/sub 2/ exposed lungs were essentially identical with average values of approx. 62 ..mu..m. This morphometric parameter was substantially increased in the E- and E + NO/sub 2/-exposed lungs; no significant differences, however, were found between the MLI values obtained with the E and E + NO/sub 2/ lungs. From these data as well as histologic examinations of lung sections for evidence of emphysema, it was concluded that (1) a subchronic, moderately high level of NO/sub 2/ exposure does not produce an irreversible emphysematous lesion in the rat model and (2) exposure of rats to 35 ppm for 25 d after elastase instillation into the lungs does not potentiate protease-induced emphysema or bring about a progression in preexisting emphysema.

  16. Nitrogen dioxide in indoor ice skating facilities: an international survey.

    PubMed

    Brauer, M; Lee, K; Spengler, J D; Salonen, R O; Pennanen, A; Braathen, O A; Mihalikova, E; Miskovic, P; Nozaki, A; Tsuzuki, T; Song, R J; Yang, X; Zeng, Q X; Drahonovska, H; Kjaergaard, S

    1997-10-01

    An international survey of nitrogen dioxide (NO2) levels inside indoor ice skating facilities was conducted. One-week average NO2 concentrations were measured inside and outside of 332 ice rinks located in nine countries. Each rink manager also completed a questionnaire describing the building, the resurfacing machines, and their use patterns. The (arithmetic) mean NO2 level for all rinks in the study was 228 ppb, with a range of 1-2,680 ppb, based on a sample collected at breathing height and adjacent to the ice surface. The mean of the second indoor sample (collected at a spectator's area) was 221 ppb, with a range of 1-3,175 ppb. The ratio of the indoor to outdoor NO2 concentrations was above 1 for 95% of the rinks sampled, indicating the presence of an indoor NO2 source (mean indoor:outdoor ratio = 20). Estimates of short-term NO2 concentrations indicated that as many as 40% of the sampled rinks would have exceeded the World Health Organization 1-hour guideline value of 213 ppb NO2 for indoor air. Statistically significant associations were observed between NO2 levels and the type of fuel used to power the resurfacer, the absence of a catalytic converter on a resurfacer, and the use of an ice edger. There were also indications that decreased use of mechanical ventilation, increased number of resurfacing operations per day, and smaller rink volumes were associated with increased NO2 levels. In rinks where the main resurfacer was powered by propane, the NO2 concentrations were higher than in those with gasoline-powered resurfacers, while the latter had NO2 concentrations higher than in those using diesel. Rinks where the main resurfacer was electric had the lowest indoor NO2 concentrations, similar to the levels measured outdoors.

  17. Absorption of nitrogen dioxide and nitric oxide by soda lime.

    PubMed

    Ishibe, T; Sato, T; Hayashi, T; Kato, N; Hata, T

    1995-09-01

    Inhaled nitric oxide (NO) is used for the treatment of pulmonary hypertension as a selective pulmonary vasodilator. However, NO is oxidized rapidly to the more toxic nitrogen dioxide (NO2). Elimination of NO2 from inspired gas is essential for safe clinical use NO. We therefore investigated the efficacy of soda lime in absorbing NO2 from NO2-containing gases. Commercially available soda limes (Soda sorb and Wako lime-A), were exposed to the following six gas mixtures containing NO and NO2 in a hypoxic carrier gas for 20 min: No. 1: NO 40 ppm; No. 2: NO 35 ppm and NO2 5 ppm; No. 3: NO 30 ppm and NO2 10 ppm; No. 4: NO 20 ppm and NO2 20 ppm; No. 5: NO 10 ppm and NO2 30 ppm; and No. 6: NO2 40 ppm. Both types of soda lime completely absorbed the NO2 in all samples when it was present (Nos 2-6). NO concentration in these gas mixtures was reduced by an amount equal to the NO2 absorbed by soda lime. NO was absorbed minimally when NO2 was not present in the mixture. Nitrite was detected from the Wako lime-A granules exposed to the test gas by the chemical analysis. These findings suggest that soda lime completely absorbs NO2 by chemical neutralization, but NO is absorbed as simultaneously absorbed NO2 only where NO and NO2 coexist. Therefore, we conclude that soda lime is useful for NO2 absorption during NO inhalation therapy but NO monitoring from a point distal to the soda lime is required for precise control of inspired NO concentration.

  18. In-vehicle nitrogen dioxide concentrations in road tunnels

    NASA Astrophysics Data System (ADS)

    Martin, Ashley N.; Boulter, Paul G.; Roddis, Damon; McDonough, Liza; Patterson, Michael; Rodriguez del Barco, Marina; Mattes, Andrew; Knibbs, Luke D.

    2016-11-01

    There is a lack of knowledge regarding in-vehicle concentrations of nitrogen dioxide (NO2) during transit through road tunnels in urban environments. Furthermore, previous studies have tended to involve a single vehicle and the range of in-vehicle NO2 concentrations that vehicle occupants may be exposed to is not well defined. This study describes simultaneous measurements of in-vehicle and outside-vehicle NO2 concentrations on a route through Sydney, Australia that included several major tunnels, minor tunnels and busy surface roads. Tests were conducted on nine passenger vehicles to assess how vehicle characteristics and ventilation settings affected in-vehicle NO2 concentrations and the in-vehicle-to-outside vehicle (I/O) concentration ratio. NO2 was measured directly using a cavity attenuated phase shift (CAPS) technique that gave a high temporal and spatial resolution. In the major tunnels, transit-average in-vehicle NO2 concentrations were lower than outside-vehicle concentrations for all vehicles with cabin air recirculation either on or off. However, markedly lower I/O ratios were obtained with recirculation on (0.08-0.36), suggesting that vehicle occupants can significantly lower their exposure to NO2 in tunnels by switching recirculation on. The highest mean I/O ratios for NO2 were measured in older vehicles (0.35-0.36), which is attributed to older vehicles having higher air exchange rates. The results from this study can be used to inform the design and operation of future road tunnels and modelling of personal exposure to NO2.

  19. Revealing the Origin of Activity in Nitrogen-Doped Nanocarbons towards Electrocatalytic Reduction of Carbon Dioxide.

    PubMed

    Xu, Junyuan; Kan, Yuhe; Huang, Rui; Zhang, Bingsen; Wang, Bolun; Wu, Kuang-Hsu; Lin, Yangming; Sun, Xiaoyan; Li, Qingfeng; Centi, Gabriele; Su, Dangsheng

    2016-05-23

    Carbon nanotubes (CNTs) are functionalized with nitrogen atoms for reduction of carbon dioxide (CO2 ). The investigation explores the origin of the catalyst's activity and the role of nitrogen chemical states therein. The catalysts show excellent performances, with about 90 % current efficiency for CO formation and stability over 60 hours. The Tafel analyses and density functional theory calculations suggest that the reduction of CO2 proceeds through an initial rate-determining transfer of one electron to CO2 , which leads to the formation of carbon dioxide radical anion (CO2 (.-) ). The initial reduction barrier is too high on pristine CNTs, resulting in a very high overpotentials at which the hydrogen evolution reaction dominates over CO2 reduction. The doped nitrogen atoms stabilize the radical anion, thereby lowering the initial reduction barrier and improving the intrinsic activity. The most efficient nitrogen chemical state for this reaction is quaternary nitrogen, followed by pyridinic and pyrrolic nitrogen.

  20. Sub-ambient carbon dioxide adsorption properties of nitrogen doped graphene

    SciTech Connect

    Tamilarasan, P.; Ramaprabhu, Sundara

    2015-04-14

    Carbon dioxide adsorption on carbon surface can be enhanced by doping the surface with heterogeneous atoms, which can increase local surface affinity. This study presents the carbon dioxide adsorption properties of nitrogen doped graphene at low pressures (<100 kPa). Graphene was exposed to nitrogen plasma, which dopes nitrogen atoms into carbon hexagonal lattice, mainly in pyridinic and pyrrolic forms. It is found that nitrogen doping significantly improves the CO{sub 2} adsorption capacity at all temperatures, due to the enrichment of local Lewis basic sites. In general, isotherm and thermodynamic parameters suggest that doped nitrogen sites have nearly same adsorption energy of surface defects and residual functional groups. The isosteric heat of adsorption remains in physisorption range, which falls with surface coverage, suggesting the distribution of magnitude of adsorption energy. The absolute values of isosteric heat and entropy of adsorption are slightly increased upon nitrogen doping.

  1. The source of carbon dioxide for gastric acid production.

    PubMed

    Steer, Howard

    2009-01-01

    The source of carbon dioxide for the chemical reaction leading to the production of gastric acid is unknown. The decarboxylation of an amino acid releases carbon dioxide. Pepsinogens provide a rich source of the amino acid arginine. Both the source of carbon dioxide, arginine, and the consequence of arginine decarboxylation, agmatine, have been studied. The site of carbon dioxide production has been related to the survival of the parietal cell. An immunohistochemical study has been carried out on glycol methacrylate embedded gastric biopsies from the normal stomach of 38 adult patients. The sections have been stained using polyclonal antibody to pepsinogen II, polyclonal antibody to agmatine, and polyclonal antibody to Helicobacter pylori. Pepsinogen II and agmatine are found in the parietal cell canaliculi. This is consistent with the production of carbon dioxide from arginine in the parietal cell canaliculi. Evidence is presented for the decarboxylation of arginine derived from the activation segment of pepsinogen as the source of carbon dioxide for the production of gastric acid. The production of carbon dioxide by the decarboxylation of arginine in the parietal cell canaliculus enables the extracellular hydration of carbon dioxide at the known site of carbonic anhydrase activity. The extracellular production of acid in the canaliculus together with the presence of agmatine helps to explain why the parietal cells are not destroyed during the formation of gastric acid. Agmatine is found in the mucus secreting cells of the stomach and its role in acid protection of the stomach is discussed. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc. PMID:18951509

  2. Statistical summary of air quality data for metropolitian Cleveland, Ohio, 1967 - 1972: Total suspended particulates, nitrogen dioxide, and sulfur dioxide

    NASA Technical Reports Server (NTRS)

    King, R. B.; Neustadter, H. E.; Fordyce, J. S.; Burr, J. C., Jr.; Cornett, C. L.

    1974-01-01

    Air-quality data for metropolitan Cleveland, Ohio, from 1967 through 1972 were collated and statistically analyzed. Total suspended particulates (TSP) departed from lognormal distribution in 1972. Nitrogen dioxide and sulfur dioxide, departed significantly from lognormal distributions in 1972. In Cleveland the Ohio standards were not met. However, the data indicate a general improvement in air quality. Unusually high precipitation (43% above the average in 1972) may be responsible in lowering these values from the 1971 levels. The mean values of TSP, NO2, and SO2 are 104, 191, and 83 microgram/cu m respectively.

  3. Comparison of peak and average nitrogen dioxide concentrations inside homes

    NASA Astrophysics Data System (ADS)

    Franklin, Peter; Runnion, Tina; Farrar, Drew; Dingle, Peter

    Most health studies measuring indoor nitrogen dioxide (NO 2) concentrations have utilised long-term passive monitors. However, this method may not provide adequate information on short-term peaks, which may be important when examining health effects of this pollutant. The aims of this study were to investigate the relationship between short-term peak (peak) and long-term average (average) NO 2 concentrations in kitchens and the effect of gas cookers on this relationship. Both peak and average NO 2 levels were measured simultaneously in the kitchens of 53 homes using passive sampling techniques. All homes were non-smoking and sampling was conducted in the summer months. Geometric mean (95% confidence interval (CI)) average NO 2 concentrations for all homes were 16.2 μg m -3 (12.7-20.6 μg m -3). There was no difference between homes with and without gas cookers ( p=0.40). Geometric mean (95%CI) peak NO 2 concentrations were 45.3 μg m -3 (36.0-57.1 μg m -3). Unlike average concentrations, peak concentrations were significantly higher in homes with gas cookers (64.0 μg m -3, 48.5-82.0 μg m -3) compared to non-gas homes (25.1 μg m -3, 18.3-35.5 μg m -3) ( p<0.001). There was only a moderate correlation between the peak and average concentrations measured in all homes ( r=0.39, p=0.004). However, when the data were analysed separately based on the presence of gas cookers, the correlation between peak and average NO 2 concentrations was improved in non-gas homes ( r=0.59, p=0.005) but was not significant in homes with gas cookers ( r=0.19, p=0.33). These results suggest that average NO 2 concentrations do not adequately identify exposure to short-term peaks of NO 2 that may be caused by gas cookers. The lack of peak exposure data in many epidemiological studies may explain some of the inconsistent findings.

  4. Novel nighttime free radical chemistry in severe nitrogen dioxide pollution episodes

    NASA Astrophysics Data System (ADS)

    Harrison, Roy M.; Shi, Ji Ping; Grenfell, J. Lee.

    During winter air pollution episodes, nitrogen dioxide concentrations can far exceed health based guidelines, but to date, there has been no wholly adequate explanation of the atmospheric chemical production of very high concentrations of nitrogen dioxide during such episodes, despite inclusion of the thermal oxidation of nitric oxide with dioxygen, as well as the well known reaction with ozone. In laboratory studies we have shown that both petrol engine exhaust and petrol vapour catalyse the thermal oxidation of nitric oxide to nitrogen dioxide and have identified certain dialkenes as the chemical agent responsible ( Shi and Harrison, 1997). It is postulated that addition of nitrogen dioxide to the dialkene forms a reactive free radical species which initiates a chain reaction during which peroxy species are formed which convert NO to NO 2. A numerical box model including explicit hydrocarbon chemistry and incorporating this mechanism, shows that rates of nitrogen dioxide production observed in London in December 1991 and hitherto unexplained, are explicable by the presence of conjugate dialkenes at concentrations comparable with those which have been observed in polluted urban atmospheres.

  5. Nitrogen dioxide (NO2) uptake by vegetation controlled by atmospheric concentrations and plant stomatal aperture

    NASA Astrophysics Data System (ADS)

    Chaparro-Suarez, I. G.; Meixner, F. X.; Kesselmeier, J.

    2011-10-01

    Nitrogen dioxide (NO2) exchange between the atmosphere and five European tree species was investigated in the laboratory using a dynamic branch enclosure system (consisting of two cuvettes) and a highly specific NO2 analyzer. NO2 measurements were performed with a sensitive gas phase chemiluminescence NO detector combined with a NO2 specific (photolytic) converter, both from Eco-Physics (Switzerland). This highly specific detection system excluded bias from other nitrogen compounds. Investigations were performed at two light intensities (Photosynthetic Active Radiation, PAR, 450 and 900 μmol m-2 s-1) and NO2 concentrations between 0 and 5 ppb. Ambient parameters (air temperature and relative humidity) were held constant. The data showed dominant NO2 uptake by the respective tree species under all conditions. The results did not confirm the existence of a compensation point within a 95% confidence level, though we cannot completely exclude emission of NO2 under very low atmospheric concentrations. Induced stomatal stricture, or total closure, by changing light conditions, as well as by application of the plant hormone ABA (Abscisic Acid) caused a corresponding decrease of NO2 uptake. No loss of NO2 to plant surfaces was observed under stomatal closure and species dependent differences in uptake rates could be clearly related to stomatal behavior.

  6. Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results

    SciTech Connect

    Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

    1990-08-01

    This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program's Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

  7. Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results

    SciTech Connect

    Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

    1990-08-01

    This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program`s Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

  8. Pulse radiolysis study of the reactions of catechins with nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Gebicki, Jerzy L.; Meisner, Piotr; Stawowska, Katarzyna; Gebicka, Lidia

    2012-12-01

    Nitrogen dioxide (•NO2), one of the oxidizing radicals formed in vivo is suspected to play a role in various pathophysiological processes. The reactions of •NO2 with dietary catechins, the group of flavonoids present in high amounts in green tea and red wine, have been investigated by pulse radiolysis method. The kinetics of the reaction of •NO2 with gallic acid have been also studied for comparison. The spectra of transient intermediates are presented. The rate constants of the reaction of •NO2 with catechin, epigallocatechin, epigallocatechin gallate and gallic acid determined by the competition method with 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) at pH 7.0 and room temperature have been found to be 0.9, 1.0, 2.3 and 0.5×108 M-1 s-1, respectively. The values for catechins are among the highest reported for the reactions of •NO2 with non-radical compounds.

  9. Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type.

    PubMed

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-06-19

    Although enhanced carbon fixation by forest trees may contribute significantly to mitigating an increase in atmospheric carbon dioxide (CO2), capacities for this vary greatly among different tree species and locations. This study compared reactions in the foliage of a deciduous and a coniferous tree species (important central European trees, beech and spruce) to an elevated supply of CO2 and evaluated the importance of the soil type and increased nitrogen deposition on foliar nutrient concentrations and cellular stress reactions. During a period of 4 years, beech (represented by trees from four different regions) and spruce saplings (eight regions), planted together on either acidic or calcareous forest soil in the experimental model ecosystem chambers, were exposed to single and combined treatments consisting of elevated carbon dioxide (+CO2, 590 versus 374 μL L(-1)) and elevated wet nitrogen deposition (+ND, 50 versus 5 kg ha(-1) a(-1)). Leaf size and foliage mass of spruce were increased by +CO2 on both soil types, but those of beech by +ND on the calcareous soil only. The magnitude of the effects varied among the tree origins in both species. Moreover, the concentration of secondary compounds (proanthocyanidins) and the leaf mass per area, as a consequence of cell wall thickening, were also increased and formed important carbon sinks within the foliage. Although the species elemental concentrations differed in their response to CO2 fertilization, the +CO2 treatment effect was weakened by an acceleration of cell senescence in both species, as shown by a decrease in photosynthetic pigment and nitrogen concentration, discolouration and stress symptoms at the cell level; the latter were stronger in beech than spruce. Hence, young trees belonging to a species with different ecological niches can show contrasting responses in their foliage size, but similar responses at the cell level, upon exposure to elevated levels of CO2. The soil type and its nutrient supply

  10. Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type.

    PubMed

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-01-01

    Although enhanced carbon fixation by forest trees may contribute significantly to mitigating an increase in atmospheric carbon dioxide (CO2), capacities for this vary greatly among different tree species and locations. This study compared reactions in the foliage of a deciduous and a coniferous tree species (important central European trees, beech and spruce) to an elevated supply of CO2 and evaluated the importance of the soil type and increased nitrogen deposition on foliar nutrient concentrations and cellular stress reactions. During a period of 4 years, beech (represented by trees from four different regions) and spruce saplings (eight regions), planted together on either acidic or calcareous forest soil in the experimental model ecosystem chambers, were exposed to single and combined treatments consisting of elevated carbon dioxide (+CO2, 590 versus 374 μL L(-1)) and elevated wet nitrogen deposition (+ND, 50 versus 5 kg ha(-1) a(-1)). Leaf size and foliage mass of spruce were increased by +CO2 on both soil types, but those of beech by +ND on the calcareous soil only. The magnitude of the effects varied among the tree origins in both species. Moreover, the concentration of secondary compounds (proanthocyanidins) and the leaf mass per area, as a consequence of cell wall thickening, were also increased and formed important carbon sinks within the foliage. Although the species elemental concentrations differed in their response to CO2 fertilization, the +CO2 treatment effect was weakened by an acceleration of cell senescence in both species, as shown by a decrease in photosynthetic pigment and nitrogen concentration, discolouration and stress symptoms at the cell level; the latter were stronger in beech than spruce. Hence, young trees belonging to a species with different ecological niches can show contrasting responses in their foliage size, but similar responses at the cell level, upon exposure to elevated levels of CO2. The soil type and its nutrient supply

  11. Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type

    PubMed Central

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-01-01

    Although enhanced carbon fixation by forest trees may contribute significantly to mitigating an increase in atmospheric carbon dioxide (CO2), capacities for this vary greatly among different tree species and locations. This study compared reactions in the foliage of a deciduous and a coniferous tree species (important central European trees, beech and spruce) to an elevated supply of CO2 and evaluated the importance of the soil type and increased nitrogen deposition on foliar nutrient concentrations and cellular stress reactions. During a period of 4 years, beech (represented by trees from four different regions) and spruce saplings (eight regions), planted together on either acidic or calcareous forest soil in the experimental model ecosystem chambers, were exposed to single and combined treatments consisting of elevated carbon dioxide (+CO2, 590 versus 374 μL L−1) and elevated wet nitrogen deposition (+ND, 50 versus 5 kg ha−1 a−1). Leaf size and foliage mass of spruce were increased by +CO2 on both soil types, but those of beech by +ND on the calcareous soil only. The magnitude of the effects varied among the tree origins in both species. Moreover, the concentration of secondary compounds (proanthocyanidins) and the leaf mass per area, as a consequence of cell wall thickening, were also increased and formed important carbon sinks within the foliage. Although the species elemental concentrations differed in their response to CO2 fertilization, the +CO2 treatment effect was weakened by an acceleration of cell senescence in both species, as shown by a decrease in photosynthetic pigment and nitrogen concentration, discolouration and stress symptoms at the cell level; the latter were stronger in beech than spruce. Hence, young trees belonging to a species with different ecological niches can show contrasting responses in their foliage size, but similar responses at the cell level, upon exposure to elevated levels of CO2. The soil type and its nutrient supply

  12. Studies on the effect of long-term exposure to nitrogen dioxide on serum and liver proteins level and enzyme activity in guinea pigs.

    PubMed

    Drozdz, M; Kucharz, E; Ludyga, K; Molska-Drozda, T

    1976-01-01

    Forty male guinea pigs were exposed to nitrogen dioxide in a concentration of 2 mg/m3, 8 hours daily for a period of 180 days. Forty male animals were used as a control group. The following changes were found in intoxicated animals: the decrease of total protein and seromucoid concentration in blood serum and the decrease of total protein, perchloric acid-soluble proteins, protein-bound hexosamines and sialic acids content, in liver tissue. Electrophoretic examination of the serum proteins showed the increase of alpha 1- and beta 2-globulins and the decrease of albumin concentration. Changes in the level of glycoproteins fractions and protein-bound carbohydrates in blood serum were described also. Estimation of enzymes activity showed the decrease of alanine and aspartate transaminase activity in blood serum caused by the strong decrease of the cytoplasmic fraction of these enzymes. However the simultaneous increase of the mitochondrial fraction of transaminases activity was observed. The decrease of the activity of choline esterase was found also. Similar changes of enzymes activity were found in liver tissue. Histopathological studies were done for the further clearing the influenze of nitrogen dioxide on serum and liver proteins concentration and enzymes activity. It was found that after long-term exposure to nitrogen dioxide the destruction processes may be observed in the liver. The possible mechanism of the nitrogen dioxide-induced damage of protein metabolism is discussed.

  13. Toxicity of ozone and nitrogen dioxide to alveolar macrophages: comparative study revealing differences in their mechanism of toxic action

    SciTech Connect

    Rietjens, I.M.; Poelen, M.C.; Hempenius, R.A.; Gijbels, M.J.; Alink, G.M.

    1986-01-01

    In this study the toxic mechanisms of action of ozone and nitrogen dioxide were compared using an intact cell model. Rat alveolar macrophages were exposed by means of gas diffusion through a Teflon film. In this in vitro system, ozone appeared to be 10 times more toxic than nitrogen dioxide. alpha-Tocopherol protected equally well against ozone and nitrogen dioxide. It was demonstrated that alpha-tocopherol provided its protection by its action as a radical scavenger and not by its stabilizing structural membrane effect, as (1) concentrations of alpha-tocopherol that already provided optimal protection against ozone and nitrogen dioxide did not influence the membrane fluidity of alveolar macrophages and (2) neither one of the structural alpha-tocopherol analogs tested (phytol and the methyl ether of alpha-tocopherol) could provide a protection against ozone or nitrogen dioxide comparable to the one provided by alpha-tocopherol. It was concluded that reactive intermediates scavenged by alpha-tocopherol are important in the toxic mechanism of both ozone and nitrogen dioxide induced cell damage. However, further results presented strongly confirmed that the kind of radicals and/or reactive intermediates, and thus the toxic reaction mechanism involved, must be different in ozone- and nitrogen dioxide-induced cell damage. This was concluded from the observations that showed that (1) vitamin C provided significantly better protection against nitrogen dioxide than against an equally toxic dose of ozone, (2) glutathione depletion affected the cellular sensitivity toward ozone to a significantly greater extent than the sensitivity towards nitrogen dioxide, and (3) the scavenging action of alpha-tocopherol was accompanied by a significantly greater reduction in its cellular level during nitrogen dioxide exposure than during exposure to ozone.

  14. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Penalties for excess emissions of sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) EXCESS EMISSIONS § 77.6 Penalties for excess emissions...

  15. Near-road measurements for nitrogen dioxide and its association with traffic exposure zones

    EPA Science Inventory

    Near-road measurements for nitrogen dioxide (NO2) using passive air samplers were collected weekly in traffic exposure zones (TEZs) in the Research Triangle area of North Carolina (USA) during Fall 2014. Land use regression (LUR) analysis and pairwise comparisons of T...

  16. Nitrogen dioxide produced by self-sustained pyrolysis of nitrous oxide

    NASA Technical Reports Server (NTRS)

    Sabol, A. P.

    1965-01-01

    Apparatus is developed for achieving continuous self-sustaining pyrolysis reaction in the production of nitrogen dioxide from nitrous oxide. The process becomes self-sustaining because of the exothermic reaction and the regenerative heating of the gases in the pyrolysis chamber.

  17. Ambient intercomparison of direct and indirect methods for ambient nitrogen dioxide

    EPA Science Inventory

    AbstractRecent advances in measurement techniques for nitrogen dioxide (NO2), along with known interferences in the current Federal Reference Method (FRM) have created the need for NO2 measurement method research within EPA’s Office of Research and Development. Current meth...

  18. Synergistic effects of exposure to concentrated ambient fine pollution particles and nitrogen dioxide in humans

    EPA Science Inventory

    Exposure to single pollutants such as ambient particulate matter (PM) is associated with adverse health effects. It is unclear, however, if simultaneous exposure to multiple air pollutants (e.g. PM and ozone or nitrogen dioxide), a more real world scenario, results in non-additiv...

  19. Mutagenicity of nitro derivatives induced by exposure of aromatic compounds to nitrogen dioxide.

    PubMed

    Tokiwa, H; Nakagawa, R; Morita, K; Ohnishi, Y

    1981-08-01

    Mutagenic nitro derivatives were readily induced when 6 kinds of chemicals were exposed to 10 ppm of nitrogen dioxide (NO2). Single nitro derivatives were formed from pyrene, phenanthrene, fluorene or chrysene. Carbazole and fluoranthene each produced 2 derivatives substituted with nitro groups at different positions. The formation of nitro derivatives was enhanced by exposure of pyrene to NO2 containing nitric acid (HNO3, less than 100-fold enhancement) or sulphur dioxide (SO2, less than 15-fold enhancement). After 24 h of exposure the yields of the nitro derivative were 0.02% with 1 ppm of NO2 in air and 2.85% with NO2 (1 ppm) containing traces of HNO3. The nitro derivatives from all but phenanthrene and carbazole were chemically identified by means of gas chromatography (GC) and mass spectrometry (MS), and the mutagenicity of the 4 kinds of authentic nitro derivatives was tested by using Salmonella strains TA98 and TA1538 with or without the S9 fraction from rat liver treated with Aroclor 1254. The nitro derivative induced from pyrene was determined to be 1-nitropyrene; that of chrysene was 6-nitrochrysene; that of fluorene was 2-nitrofluorene; and those of fluoranthene were 3-nitrofluoranthene, and 8-nitrofluoranthene. Tested with strain TA98 in the absence of the S9 fraction, the first 4 of these derivatives yielded, respectively, 3050, 269, 433 and 13 400 revertants per nmole. Thus, each nitro derivative formed was potentially a direct-acting frameshift-type mutagen. Each compound exposed to NO2 showed a decreased mutagenic activity when tested in the presence of S9 mix. A possible explanation comes from experiments in which 1-nitropyrene was incubated with the S9 mix at 37 degree C for 10 min, and 1-aminopyrene was formed. The mutagenic activity of 1-aminopyrene was appreciable, but only about one-tenth of that of 1-nitropyrene in the Ames test. PMID:7022189

  20. Nitrogen dioxide assimilation as affected by light level

    SciTech Connect

    Srivastava, H. ); Ormond, D.; Marie, B. )

    1989-04-01

    The air pollutant NO{sub 2} is absorbed and assimilated by plants to serve as a source of nitrogen but only to a limited extent. The objective of this research was to identify the constraints on NO{sub 2} assimilation. Differential light levels were used to manipulate carbohydrate metabolites available for nitrogen assimilation. Bean plants were grown at four light levels with or without nutrient nitrate and exposed to 0.25 ppm NO{sub 2} for 6h each day. Growth of roots and shoots was inhibited by NO{sub 2} in both the presence and absence of nutrient nitrate. The inhibition was most pronounced at the lowest light level. Light level similarly influenced the effect of nitrate and of NO{sub 2} on soluble protein, nitrate nitrogen and Kjeldahl nitrogen in the root and shoot tissues. Two experiments demonstrated that the injurious effects of NO{sub 2} are more pronounced at low light than at high light and that more NO{sub 2} is assimilated into soluble shoot protein at higher light levels.

  1. Diffusion of benzoic acid (1); carbon dioxide (2); methanol (3)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) benzoic acid; (2) carbon dioxide; (3) methanol

  2. Diffusion of benzoic acid (1); carbon dioxide (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) benzoic acid; (2) carbon dioxide

  3. Hydrogen Storage in the Carbon Dioxide - Formic Acid Cycle.

    PubMed

    Fink, Cornel; Montandon-Clerc, Mickael; Laurenczy, Gabor

    2015-01-01

    This year Mankind will release about 39 Gt carbon dioxide into the earth's atmosphere, where it acts as a greenhouse gas. The chemical transformation of carbon dioxide into useful products becomes increasingly important, as the CO(2) concentration in the atmosphere has reached 400 ppm. One approach to contribute to the decrease of this hazardous emission is to recycle CO(2), for example reducing it to formic acid. The hydrogenation of CO(2) can be achieved with a series of catalysts under basic and acidic conditions, in wide variety of solvents. To realize a hydrogen-based charge-discharge device ('hydrogen battery'), one also needs efficient catalysts for the reverse reaction, the dehydrogenation of formic acid. Despite of the fact that the overwhelming majority of these reactions are carried out using precious metals-based catalysts (mainly Ru), we review here developments for catalytic hydrogen evolution from formic acid with iron-based complexes. PMID:26842324

  4. Tropospheric nitrogen dioxide column retrieval based on ground-based zenith-sky DOAS observations

    NASA Astrophysics Data System (ADS)

    Tack, Frederik; Hendrick, Francois; Goutail, Florence; Fayt, Caroline; Merlaud, Alexis; Pinardi, Gaia; Pommereau, Jean-Pierre; Van Roozendael, Michel

    2014-05-01

    Nitrogen dioxide (NO2) is one of the most important chemically active trace gases in the troposphere. Listed as primary pollutant, it is also a key precursor in the formation of tropospheric ozone, aerosols, and acid rain, and can contribute locally to radiative forcing. The long-term monitoring of this species is therefore of great relevance. Here we present a new method to retrieve tropospheric NO2 vertical column amounts from ground-based zenith-sky measurements of scattered sunlight. It is based on a four-step approach consisting of (1) the DOAS analysis of zenith radiance spectra using a fixed reference spectrum corresponding to low tropospheric NO2 content, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total slant column using stratospheric vertical columns measured at twilight and simulated stratospheric NO2 diurnal variation, (4) estimation of the tropospheric vertical columns by dividing the resulting tropospheric slant columns by appropriate air mass factors. The retrieval algorithm is tested on a 2 month dataset acquired from June to July 2009 by the BIRA MAX-DOAS instrument in the framework of the Cabauw (51.97° N, 4.93° E) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI). The tropospheric vertical column amounts derived from zenith-sky observations are compared to the vertical columns retrieved from the off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to data of a co-located SAOZ (Système d'Analyse par Observations Zénithales) spectrometer operated by LATMOS. First results show a good agreement between the different data sets with correlation coefficients and slopes close to or larger than 0.85. We observe that the main error sources arise from the uncertainties in the determination of the residual NO2 amount in the reference spectrum, the stratospheric NO2 abundance and

  5. Statistical summary and trend evaluation of air quality data for Cleveland, Ohio in 1967 to 1971: Total suspended particulate, nitrogen dioxide, and sulfur dioxide

    NASA Technical Reports Server (NTRS)

    Neustadter, H. E.; Sidik, S. M.; Burr, J. C., Jr.

    1972-01-01

    Air quality data for Cleveland, Ohio, for the period of 1967 to 1971 were collated and subjected to statistical analysis. The total suspended particulate component is lognormally distributed; while sulfur dioxide and nitrogen dioxide are reasonably approximated by lognormal distributions. Only sulfur dioxide, in some residential neighborhoods, meets Ohio air quality standards. Air quality has definitely improved in the industrial valley, while in the rest of the city, only sulfur dioxide has shown consistent improvement. A pollution index is introduced which displays directly the degree to which the environmental air conforms to mandated standards.

  6. The interaction of ozone and nitrogen dioxide in the stratosphere of East Antarctica

    NASA Astrophysics Data System (ADS)

    Bruchkouski, Ilya; Krasouski, Aliaksandr; Dziomin, Victar; Svetashev, Alexander

    2016-04-01

    At the Russian Antarctic station "Progress" (S69°23´, E76°23´) simultaneous measurements of trace gases using the MARS-B (Multi-Axis Recorder of Spectra) instrument and PION-UV spectro-radiometer for the time period from 05.01.2014 to 28.02.2014 have been performed. Both instruments were located outdoors. The aim of the measurements was to retrieve the vertical distribution of ozone and nitrogen dioxide in the atmosphere and to study their variability during the period of measurements. The MARS-B instrument, developed at the National Ozone Monitoring Research and Education Centre of the Belarusian State University (NOMREC BSU), successfully passed the procedure of international inter-comparison campaign MAD-CAT 2013 in Mainz, Germany. The instrument is able to record the spectra of scattered sunlight at different elevation angles within a maximum aperture of 1.3°. 12 elevation angles have been used in this study, including the zenith direction. Approximately 7000 spectra per day were registered in the range of 403-486 nm, which were then processed by DOAS technique aiming to retrieve differential slant columns of ozone, nitrogen dioxide and oxygen dimer. Furthermore, total nitrogen dioxide column values have been retrieved employing the Libradtran radiative transfer model. The PION-UV spectro-radiometer, also developed at NOMREC BSU, is able to record the spectra of scattered sunlight from the hemisphere in the range of 280-430 nm. The registered spectra have been used to retrieve the total ozone column values employing the Stamnes method. In this study observational data from both instruments is presented and analyzed. Furthermore, by combining analysis of this data with model simulations it is shown that decreases in nitrogen dioxide content in the upper atmosphere can be associated with increases in total ozone column values and rising of the ozone layer upper boundary. Finally, the time delay between changes in nitrogen dioxide and ozone values is

  7. Nitrogen dioxide exposure--influence on rat testes.

    PubMed

    Kripke, B J; Sherwin, R P

    1984-05-01

    Prolonged intermittent exposure to subanesthetic concentrations of nitrous oxide (N2O) can impair spermatogenesis in the LEW/f mai rat. USP purity standards state that N2O used for medical purposes may contain other oxides of nitrogen such as NO and NO2 as impurities at concentrations up to one part per million (ppm) each. The question thus arises as to whether prolonged exposure to N2O may be associated with adverse health effects from oxides of nitrogen other than N2O, particularly NO2. NO2 has demonstrated biological toxicity at concentrations as low as 0.3 ppm. In this study, rats were exposed to filtered air with and without 1 ppm NO2 for 7 hr/day, 5 days/week, for 21 days. No gross or light microscopy abnormality was found in the testes of NO2-exposed rats. Serum vitamin B12 levels were within normal limits. The findings indicate that NO2 exposure under the test conditions does not in itself impair spermatogenesis or alter B12 levels.

  8. Surface area of montmorillonite from the dynamic sorption of nitrogen and carbon dioxide

    USGS Publications Warehouse

    Thomas, J.; Bohor, B.F.

    1968-01-01

    Surface area determinations were made on a montmorillonite with various cations emplaced on the exchangeable sites, utilizing nitrogen and carbon dioxide as adsorbates at 77 ??K and 195 ??K, respectively, in a dynamic system. From the fraction of a Mississippi montmorillonite less than about 1 ?? in size, samples were prepared by replacing the original exchangeable cations with Li+, Na+, K+, Rb+, Cs+, Mg++, Ca++, Ba++, and NH4+, forming a series of homoionic montmorillonite species. Surface areas from 3-point B.E.T. plots (half-hour adsorption points), with nitrogen as the adsorbate, ranged from 61 m2/g for Li-montmorillonite to 138 m2/g for Cs-montmorillonite, thus reflecting a certain degree of nitrogen penetration between layers. Complete penetration should theoretically result in a surface area of over 300 m2/g for this clay with a nitrogen monolayer between each pair of platelets. The experimental data indicate that the extent of penetration is time-dependent and is also a function of the interlayer forces as governed by the size and charge of the replaceable cation. This finding negates the generally accepted concept that nitrogen at 77 ??K does not penetrate the layers and provides a measure only of the external surface of expandable clay minerals. A further measure of the variation of interlayer forces is provided by the adsorption of carbon dioxide at 195 ??K. Surface area values ranged from 99 m2/g for Li-montmorillonite to 315 m2/g for Csmontmorillonite. Although the carbon dioxide molecule is larger than the nitrogen molecule, its greater penetration apparently is a result of its being kinetically more energetic (with a larger diffusion coefficient) at its higher adsorption temperature. Similar differences have been found with both adsorbates in the study of microporous substances, such as coal, where activated diffusion is of considerable significance. ?? 1968.

  9. Nitrogen dioxide reaction with proteins: Evidence for peptide bond cleavage at lysine residues

    SciTech Connect

    Hood, D.B.

    1991-01-01

    Nitrogen dioxide (NO{sub 2}), an air pollutant produced by burning fossil fuels and a component of cigarette smoke, is thought to contribute to the pathogenesis of pulmonary diseases, such as emphysema. To gain information on the mechanism by which NO{sub 2} damages the lung, in vitro exposures of {alpha}{sub 1}-proteinase inhibitor ({alpha}{sub 1}-PI), elastin, bovine serum albumin (BSA), human serum albumin (HSA) and synthetic poly-L-lysine were performed. A genetic deficiency of {alpha}{sup 1}-PI predisposes humans to emphysema and NO{sub 2} has been hypothesized to damage {alpha}{sub 1}-PI, which would leave proteases such as human neutrophil elastase, (HNE) free to attack lung structural proteins. The ability of {alpha}{sub 1}-PI to inhibit HNE declined with exposure to 50% of the control value at molar ratios of NO{sub 2}:{alpha}{sub 1}-PI of 400:1 and greater. Exposure of {alpha}{sub 1}-PI to NO{sub 2} resulted in a 50% lose of immunoreactivity with either monoclonal or polyclonal antibodies in an enzyme-linked immunosorbent assay at molar ratios of NO{sub 2}:{alpha}{sub 1}-PI of essentially 100:1 and greater. The mechanisms of these effects were investigated via ultraviolet-visible spectroscopy and amino acid analysis. The remaining target molecules were labeled by reductive methylation of amino groups with {sup 3}H-HCHO prior to treatment with NO{sub 2} in aqueous solutions at physiological pH. Time course exposure of 5 mg {sup 3}H-insoluble bovine ligamentum nuchae elastin suspensions with up to 120 {mu}moles of NO{sub 2} resulted in 90% solubilization of the label. Amino acid analysis of the soluble and insoluble fractions from these exposures confirmed that 80% of the {sup 3}H-dimethyllysine residues were in the soluble fraction.

  10. Heterogeneous reactions of surface-adsorbed catechol with nitrogen dioxide: substrate effects for tropospheric aerosol surrogates.

    PubMed

    Woodill, Laurie A; Hinrichs, Ryan Z

    2010-09-28

    Surface-adsorbed organics can alter the chemistry of tropospheric aerosols thereby impacting photochemical cycles and altering aerosol properties. The nature of the surface can also influence the chemistry of the surface-adsorbed organic. We employed diffuse reflectance infrared spectroscopy (DRIFTS) to monitor the adsorption of gaseous catechol on several tropospheric aerosol surrogates and to investigate the subsequent reactivity of adsorbed catechol with nitrogen dioxide. The dark heterogeneous reaction of NO(2) with NaCl-adsorbed catechol produced 4-nitrocatechol, 1,2-benzoquinone, and the ring-cleaved product muconic acid, with product yields of 88%, 8%, and 4% at relative humidity (RH) < 2%, respectively. The reaction was first-order with respect to both catechol and NO(2). The reactive uptake coefficient for NO(2) + NaCl-adsorbed catechol increased from 3 x 10(-6) at <2% RH to 7 x 10(-6) at 30% RH. These reactions were more than two orders of magnitude more reactive than NaCl without adsorbed catechol. The 4-nitrocatechol product yield was enhanced on NaF, while NaBr-adsorbed catechol produced considerably more 1,2-benzoquinone and muconic acid. This substrate effect is discussed in terms of each substrate's ability to polarize the phenol group and hinder hydrogen atom abstraction from intermediate o-semiquinone radicals. These dark heterogeneous reactions may alter the UV-visible absorbing properties of tropospheric aerosols and may also contribute as a dark source of NO(2)(-)/HONO. These results contrast prior observations which found pure catechol thin films unreactive with NO(2), highlighting the need to specifically consider substrate and matrix effects in laboratory systems.

  11. Ozone and nitrogen dioxide changes in the stratosphere during 1979-84

    NASA Technical Reports Server (NTRS)

    Callis, Linwood B.; Natarajan, Murali

    1986-01-01

    Analyses of stratospheric nitrogen dioxide distributions as measured by four different satellite experiments indicate midlatitude increases of up to 75 percent during the 1979-84 period. These increases are attributed to enhanced upper atmospheric formation of odd nitrogen during solar cycle 21 with downward transport to the stratosphere. The increases in NO2 provide an explanation for the recently observed dramatic springtime minima in the Antarctic ozone and suggest the reason for the reported midlatitude stratospheric ozone decreases observed by satellite and ground-based stations since the mid 1970s.

  12. Nitrate formation from atmospheric nitrogen and oxygen photocatalysed by nano-sized titanium dioxide.

    PubMed

    Yuan, Shi-Jie; Chen, Jie-Jie; Lin, Zhi-Qi; Li, Wen-Wei; Sheng, Guo-Ping; Yu, Han-Qing

    2013-01-01

    The concentration of nitrate in aquatic systems is rising with the development of modern industry and agriculture, causing a cascade of environmental problems. Here we describe a previously unreported nitrate formation process. Both indoor and outdoor experiments are conducted to demonstrate that nitrate may be formed from abundant atmospheric nitrogen and oxygen on nano-sized titanium dioxide surfaces under UV or sunlight irradiation. We suggest that nitric oxide is an intermediate product in this process, and elucidate its formation mechanisms using first-principles density functional theory calculations. Given the expanding use of titanium dioxide worldwide, such a titanium dioxide-mediated photocatalysis process may reveal a potentially underestimated source of nitrate in the environment, which on one hand may lead to an increasing environmental pollution concern, and on the other hand may provide an alternative, gentle and cost-effective method for nitrate production.

  13. Precipitation polymerization of acrylic acid in supercritical carbon dioxide

    SciTech Connect

    Romack, T.J.; Maury, E.E.; DeSimone, J.M.

    1995-02-13

    Increasing concern regarding the dissemination of chemical waste (both aqueous and organic) into their environment has prompted considerable interest in new technologies aimed at reducing current waste streams. Processes utilizing carbon dioxide in lieu of conventional solvents for chemical manufacturing and processing provide a viable route to achieving near-zero waste production for these important industries. The authors report the successful precipitation polymerization of acrylic acid in supercritical carbon dioxide at pressure ranging from 125 to 345 bar utilizing AIBN as a free radical initiator. Analyses by gel permeation chromatography (GPC) and scanning electron microscopy (SEM) indicate that for the pressure range studied there is no appreciable effect on product molecular weight, molecular weight distribution, or particle size or morphology. In addition, effective molecular weight control was demonstrated for precipitation polymerizations of acrylic acid in CO{sub 2} through the use of ethyl mercaptan as a chain transfer agent.

  14. Fast gas chromotography with luminol detection for measurement of nitrogen dioxide and PANs.

    SciTech Connect

    Gaffney, J. S.; Marley, N. A.; Drayton, P. J.

    1999-09-30

    Fast capillary gas chromatography has been coupled to a luminol-based chemiluminescence detection system for the rapid monitoring of nitrogen dioxide and peroxyacyl nitrates. A first-generation instrument was described recently (Gaffney et al., 1998). This system is capable of monitoring nitrogen dioxide and peroxyacyl nitrates (PANs; to and including the C4 species) with 1-min time resolution. This is an improvement by a factor of five over gas chromatography methods with electron capture detection. In addition, the luminol method is substantially less expensive than laser fluorescent detection or mass spectroscopic methods. Applications in aircraft-based research have been published electronically and will appear shortly in Environmental Science and Technology (Gaffney et al., 1999a). An improved version of the instrument that has been designed and built makes use of a Hammamatsu photon-counting system. Detection limits of this instrumentation are at the low tens of ppt. The range of the instrument can be adjusted by modifying sampling volumes and detection counting times. A review of past work and of recent application of the instrumentation to field measurements of nitrogen dioxide and PANs is presented. The data clearly indicate that the luminol approach can determine the target species with time resolution of less than 1 min. Examples of applications for estimation of peroxyacetyl radical concentrations and nitrate radical formation rates are also presented. This instrumentation can further be used for evaluation of surfaces for loss of nitrogen dioxide and PANs, phenomena of possible importance for sampling interfaces and chamber wall design. Our high-frequency field data clearly indicate that the ''real world'' is not well mixed and that turbulent mixing and plume-edge chemistries might play an important role in urban- and regional-scale interactions. Dynamic flow systems might be required to evaluate such effects in new-generation chamber studies.

  15. Intercomparison among tropospheric ozone and nitrogen dioxide data obtained by satellite- and ground-based measurements

    NASA Astrophysics Data System (ADS)

    Noguchi, K.; Urita, N.; Ohta, E.; Hayashida, S.; Richter, A.; Burrows, J. P.; Liu, X.; Chance, K.; Ziemke, J. R.

    2005-12-01

    Rapid economical growth and industrial development in East Asian regions are causing serious air pollution. The influence of such air pollution is not limited to a local scale but reaches an intercontinental or hemispheric scale. Satellite-borne observations can monitor the behaviors of air pollutants in a global scale for long periods with a single instrument. In particular, ozone and nitrogen dioxide in the troposphere have a crucial role in air pollution, and many studies have tried to derive those species. Recently, instrumentations and retrieval techniques have made a lot of progress in measurements of tropospheric constituents. However, tropospheric observations from space need careful validation because of difficulties in detecting signals from the lower atmosphere through the middle atmosphere. In the present study, we intercompare the tropospheric ozone and nitrogen dioxide data obtained by satellite- and ground-based measurements in order to validate the satellite measurements. For the validation of tropospheric ozone, we utilize ozonesonde data provided by WOUDC, and three satellite-borne data (Tropospheric Ozone Residual (TOR), Cloud Slicing, and GOME) are intercompared. For nitrogen dioxide, we compare GOME observations with ground-based air monitoring measurements in Japan which are operationally conducted by the Ministry of the Environment Japan. This study demonstrates the validity and potential of those satellite datasets to apply for quantitative analysis of dispersion of air pollutants and their chemical lifetime. Acknowledgments. TOR data is provided by J. Fishman via http://asd-www.larc.nasa.gov/TOR/data.html. The ground observation data of nitrogen dioxide over Japan is provided by National Institute for Environmental Studies (NIES) under the collaboration study with NIES and Nara Women's University.

  16. Failure of ozone and nitrogen dioxide to enhance lung tumor development in hamsters

    SciTech Connect

    Witschi, H.; Breider, M.A.; Schuller, H.M. )

    1993-09-01

    We tested the hypothesis that the two common oxidant air pollutants, ozone and nitrogen dioxide, modulate the development of respiratory tract tumors in Syrian golden hamsters. The animals received subcutaneous injections of the carcinogen diethylnitrosamine (20 mg/kg) twice a week while being exposed continuously to an atmosphere of 0.8 parts per million (ppm)* of ozone or 15 ppm of nitrogen dioxide. Animals were killed 16 weeks or 24 to 32 weeks after the beginning of the treatment. Ozone delayed the appearance of tracheal tumors and reduced the incidence of tumors in the lung periphery. A suspected neuroendocrine differentiation of those lung tumors could not be established by immunocytochemistry due to overfixation of tissues. On the other hand, ozone seemed to mitigate development of hepatotoxic lesions mediated by diethylnitrosamine. In animals treated with diethylnitrosamine and exposed to nitrogen dioxide, fewer tracheal tumors and no lung tumors were found. Only a few lung tumors were produced in animals treated with diethylnitrosamine and kept in an atmosphere of 65% oxygen. The previously observed neuroendocrine nature of tumors induced by simultaneous exposure to diethylnitrosamine and hyperoxia could not be established because the long fixation of tissues precluded immunocytochemical stains. Animals treated with diethylnitrosamine and kept in filtered air while being housed in wire-mesh cages developed fewer lung tumors than animals given the same treatment and kept on conventional bedding in shoebox cages. Although all inhalants tested are known to produce substantial cell proliferation in the respiratory tract, it was not possible to document whether this would enhance lung tumor development. The role of the two common air pollutants, ozone and nitrogen dioxide, as possible additional risks in the pathogenesis of lung cancer in animals continues to remain uncertain.

  17. Interdigitated gate electrode field effect transistor for the selective detection of nitrogen dioxide and diisopropyl methylphosphonate

    SciTech Connect

    Kolesar, E.S. Jr.; Wiseman, J.M. )

    1989-11-01

    An interdigitated gate electrode field effect transistor (IGE-FET) coupled to an electron beam evaporated copper phthalocyanine thin film was used to selectively detect part-per-billion concentration levels of nitrogen dioxide (NO{sub 2}) and diisopropyl methylphosphonate (DIMP). The sensor is excited with a voltage pulse, and the time- and frequency-domain responses are measured. The envelopes of the magnitude of the normalized difference frequency spectrums reveal features that unambiguously distinguish NO{sub 2} and DIMP exposures.

  18. Evaluation of land use regression models (LURs) for nitrogen dioxide and benzene in four U.S. Cities.

    EPA Science Inventory

    Spatial analysis studies have included application of land use regression models (LURs) for health and air quality assessments. Recent LUR studies have collected nitrogen dioxide (NO2) and volatile organic compounds (VOCs) using passive samplers at urban air monitoring networks ...

  19. Silicon dioxide thin film mediated single cell nucleic acid isolation.

    PubMed

    Bogdanov, Evgeny; Dominova, Irina; Shusharina, Natalia; Botman, Stepan; Kasymov, Vitaliy; Patrushev, Maksim

    2013-01-01

    A limited amount of DNA extracted from single cells, and the development of single cell diagnostics make it necessary to create a new highly effective method for the single cells nucleic acids isolation. In this paper, we propose the DNA isolation method from biomaterials with limited DNA quantity in sample, and from samples with degradable DNA based on the use of solid-phase adsorbent silicon dioxide nanofilm deposited on the inner surface of PCR tube.

  20. Silicon Dioxide Thin Film Mediated Single Cell Nucleic Acid Isolation

    PubMed Central

    Bogdanov, Evgeny; Dominova, Irina; Shusharina, Natalia; Botman, Stepan; Kasymov, Vitaliy; Patrushev, Maksim

    2013-01-01

    A limited amount of DNA extracted from single cells, and the development of single cell diagnostics make it necessary to create a new highly effective method for the single cells nucleic acids isolation. In this paper, we propose the DNA isolation method from biomaterials with limited DNA quantity in sample, and from samples with degradable DNA based on the use of solid-phase adsorbent silicon dioxide nanofilm deposited on the inner surface of PCR tube. PMID:23874571

  1. The carbon-nitrogen balance of the nodule and its regulation under elevated carbon dioxide concentration.

    PubMed

    Libault, Marc

    2014-01-01

    Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2). In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  2. Validation tests of a new high uptake rate passive sampler for nitrogen dioxide measurements.

    PubMed

    Piechocki-Minguy, A; Plaisance, H; Garcia-Fouqué, S; Galloo, J C; Guillermo, R

    2003-12-01

    This study explains the main characteristics of a new passive sampler which is able to give reliable nitrogen dioxide measurements for short time sampling. The sampling rate was found to be on average 0.89 cm3 s(-1) for indoor sampling and 1.00 cm3 s(-1) for outdoor sampling. The detection limit was evaluated at 11 microg m(-3) for a one-hour measurement. In field conditions, the passive sampler measurements were in agreement with those of the chemiluminescent NOx monitors. Measurement uncertainties were estimated at 34% and 38% for laboratory tests in conditions corresponding respectively to indoor and outdoor measurements and were evaluated at 28 to 37% depending on the nitrogen dioxide concentration for field experiments. The effects of various factors on the passive sampler were determined in an exposure chamber. The sampling rate of the retained sampler version was not significantly influenced by wind speeds superior to 0.3 m s(-1). A decrease of the uptake rate is observed for high nitrogen dioxide doses. The sampling rate increases linearly with temperature (2% per degree C). The relative humidity has only a weak effect.

  3. Effects of nitric oxide and nitrogen dioxide on bacterial growth

    NASA Technical Reports Server (NTRS)

    Mancinelli, R. L.; Mckay, C. P.

    1983-01-01

    While it is generally thought that the bactericidal effects of NO and NO2 derive from their reaction with water to form nitrous and nitric acids (Shank et al., 1962), this appears to be true only at high concentrations. The data presented here suggest that at low NO and NO2 concentrations, acids are not present in high enough concentrations to act as toxic agents. Reference is made to a study by Grant et al. (1979), which found that exposing acid forest soil to 1 ppm of NO2 did not cause the soil pH to drop. The results presented here show that at low concentrations of NO and NO2, the NO is bacteriostatic for some organisms and not for others, whereas NO2 may protect some bacteria from the inhibitory effects of NO. Since it has been shown that bacteria can divide while airborne (Dimmick et al., 1979), the present results suggest that NO at the low concentrations found in the atmosphere can select for resistant bacteria in the air and affect the viable airborne bacterial population.

  4. Effects of acid rain and sulfur dioxide on marble dissolution

    SciTech Connect

    Schuster, P.F.; Reddy, M.M. ); Sherwood, S.I. )

    1994-01-01

    Acid precipitation and the dry deposition of sulfur dioxide (SO[sub 2]) accelerate damage to carbonate-stone monuments and building materials. This study identified and quantified environmental damage to a sample of Vermont marble during storms and their preceding dry periods. Results from field experiments indicated the deposition of SO[sub 2] gas to the stone surface during dry periods and a twofold increase in marble dissolution during coincident episodes of low rain rate and decreased rainfall pH. The study is widely applicable to the analysis of carbonate-stone damage at locations affected by acid rain and air pollution.

  5. Effects of acid rain and sulfur dioxide on marble dissolution

    USGS Publications Warehouse

    Schuster, Paul F.; Reddy, Michael M.; Sherwood, Susan I.

    1994-01-01

    Acid precipitation and the dry deposition of sulfur dioxide (SO2) accelerate damage to carbonate-stone monuments and building materials. This study identified and quantified environmental damage to a sample of Vermont marble during storms and their preceding dry periods. Results from field experiments indicated the deposition of SO2 gas to the stone surface during dry periods and a twofold increase in marble dissolution during coincident episodes of low rain rate and decreased rainfall pH. The study is widely applicable to the analysis of carbonate-stone damage at locations affected by acid rain and air pollution.

  6. Abrupt recent trend changes in atmospheric nitrogen dioxide over the Middle East

    PubMed Central

    Lelieveld, Jos; Beirle, Steffen; Hörmann, Christoph; Stenchikov, Georgiy; Wagner, Thomas

    2015-01-01

    Nitrogen oxides, released from fossil fuel use and other combustion processes, affect air quality and climate. From the mid-1990s onward, nitrogen dioxide (NO2) has been monitored from space, and since 2004 with relatively high spatial resolution by the Ozone Monitoring Instrument. Strong upward NO2 trends have been observed over South and East Asia and the Middle East, in particular over major cities. We show, however, that a combination of air quality control and political factors, including economical crisis and armed conflict, has drastically altered the emission landscape of nitrogen oxides in the Middle East. Large changes, including trend reversals, have occurred since about 2010 that could not have been predicted and therefore are at odds with emission scenarios used in projections of air pollution and climate change in the early 21st century. PMID:26601240

  7. Abrupt recent trend changes in atmospheric nitrogen dioxide over the Middle East.

    PubMed

    Lelieveld, Jos; Beirle, Steffen; Hörmann, Christoph; Stenchikov, Georgiy; Wagner, Thomas

    2015-08-01

    Nitrogen oxides, released from fossil fuel use and other combustion processes, affect air quality and climate. From the mid-1990s onward, nitrogen dioxide (NO2) has been monitored from space, and since 2004 with relatively high spatial resolution by the Ozone Monitoring Instrument. Strong upward NO2 trends have been observed over South and East Asia and the Middle East, in particular over major cities. We show, however, that a combination of air quality control and political factors, including economical crisis and armed conflict, has drastically altered the emission landscape of nitrogen oxides in the Middle East. Large changes, including trend reversals, have occurred since about 2010 that could not have been predicted and therefore are at odds with emission scenarios used in projections of air pollution and climate change in the early 21st century. PMID:26601240

  8. Mucus protection and airway peroxidation following nitrogen dioxide exposure in the rat

    SciTech Connect

    Cavanagh, D.G.; Morris, J.B.

    1987-01-01

    In the current study, biochemical measures of lipid peroxidation following 4-h inhalation exposure to 76 mg/m/sup 3/ (40 ppm) nitrogen dioxide were correlated with measures of deposition and tissue antioxidant levels in the nasal cavity and the trachea of the Fischer rat. In addition, respirator-tract mucus samples were collected via esophageal cannulation and nasopharyngeal lavage over known time periods, and were analyzed for phospholipid (PL) content to provide an index of the unsaturated lipids (UL) that they may contain. Nasal deposition efficiency averaged 25%, corresponding to an absolute deposition rate of 41 nmol/min. Vitamin E levels averaged 1.7, 5.9, and 0.7 nmol/..mu..mol PL in nasal, tracheal, and pulmonary tissues, respectively. The level in the trachea was significantly higher than in the other tissues. The overall mucous PL transport rate was less than 0.013 nmol/min, suggesting the PL of the mucous lining layer could not offer significant protection against the inhaled NO/sub 2/. Conjugated dienes were detected in two of four pooled nasal tissue samples. Thiobarbituric acid-reactive material levels in tracheal tissues were significantly elevated over control levels by NO/sub 2/. Thus, despite the relatively high vitamin E levels, 4-h NO/sub 2/ exposure appeared to result in lipid peroxidation in the trachea and, perhaps, in the nasal airways of the rat, a result that correlated with the apparent lack of oxidant-scavenging species in the mucus lining these airways.

  9. Fiber optic sensor for simultaneous determination of atmospheric nitrogen dioxide, ozone, and relative humidity.

    PubMed

    Ohira, Shin-ichi; Dasgupta, Purnendu K; Schug, Kevin A

    2009-06-01

    We describe a novel optical sensor for the simultaneous measurement of atmospheric nitrogen dioxide (NO(2)), ozone (O(3)), and relative humidity (RH). A transparent backing thin layer silica gel chromatographic plate impregnated with 8-amino-1-naphthol-5-sulfonic acid (ANS) is used as the collection/sensor element. The plate transmittance is probed by three discrete light emitting diodes (LEDs) centered, respectively, at 442, 525, and 850 nm. The transmission of the plate changes reversibly across visible to NIR wavelengths as the RH around the plate changes; this is the basis for a limited-resolution RH sensor. The ANS on the plate reacts to form brown and pink colored products, respectively, when it reacts with NO(2) and O(3). The sample air impinges on the plate via an entrance nozzle. The LEDs are alternately turned on in a preprogrammed manner and the light is brought to the impregnated face of the plate by a three-legged fiber optic. The transmitted light is detected on the obverse side of the plate. The 850 nm signal provides the RH value and optionally serves as the reference measurement for the other two wavelengths; the NO(2) and O(3) reaction products do not absorb at this wavelength. The absorbance at 442 and 525 nm, thus referenced against 850 nm, are used to obtain NO(2) and O(3) concentrations from a pair of simultaneous equations. For a sampling period of 5 min, the limits of detection (LOD) based on 3 times the standard deviation of blank responses were 0.64 and 0.42 ppbv for NO(2) and O(3), respectively. Data obtained with collocated commercial instruments (O(3) induced chemiluminescence analyzer for NO(2) and UV-absorption for O(3)) show good agreement. Overall, this provides a viable affordable approach for inexpensive measurement of atmospheric NO(2) and O(3).

  10. Development of a Hydrazine/Nitrogen Dioxide Fiber Optic Sensor

    NASA Technical Reports Server (NTRS)

    Andrawis, Alfred S.; Santiago, Josephine

    2003-01-01

    Bromothymol Blue (BT)/Bromocresol Green (BG) mixture (1/1) in hydrogel (l/l), produces a blue-green indicator for HZ and/or NO2. The stability over a two months period of this BT/BG (1/1) indicator solution was tested and no evidence of performance deterioration was detected. A dual HZ/NO2 prototype sensor utilizing an acid-base indicator was previously constructed. A monitor and control circuit are also designed, built d tested during the course of this project. The circuit is controlled with Motorola MC68HC II microcontroller evaluation board to monitor the voltage level out of the photodetector. Low-pass filter and amplifier are used to interface the sensor's small voltage with the microcontroller's AD input. The sensor, interface circuit and the microcontroller board are then all placed in one unit and powered with a single power supply. The unit is then tested several times and the response was consistent and proved the feasibility of dual "J@ leak detection. Other sensor types, suitable for silica glass fiber, smaller in size, more rugged and suitable for use on board of the Space Shuttle and missile canisters, are then proposed.

  11. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    PubMed Central

    Fujioka, Kouki; Futamura, Yasuhiro; Shiohara, Tomoo; Hoshino, Akiyoshi; Kanaya, Fumihide; Manome, Yoshinobu; Yamamoto, Kenji

    2009-01-01

    Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin. PMID:19582225

  12. Surface area of vermiculite with nitrogen and carbon dioxide as adsorbates

    USGS Publications Warehouse

    Thomas, J.; Bohor, B.F.

    1969-01-01

    Surface-area studies were made on several homoionic vermiculites with both nitrogen and carbon dioxide as adsorbates. These studies show that only very slight penetration occurs between individual vermiculite platelets. This is in contrast to an earlier investigation of montmorillonite where it was found that the degree of penetration between layers is quite high, particularly for carbon dioxide, and is governed by the size and charge of the interlayer cation. The inability of these adsorbates to penetrate substantially between vermiculite platelets is due primarily to this mineral's high surface-charge density. The extent of penetration of nitrogen and carbon dioxide at the edges of vermiculite platelets, though slight, is influenced by the coordinated water retained within the sample at a given degassing temperature. Forces between layers are weakened with increasing water content, which permits slightly greater penetration by adsorbate gases. Thus, the surface area of vermiculite, as determined by gas adsorption, is larger than the calculated external surface area based upon particle size and shape considerations. In addition, "extra" surface is provided by the lifting and scrolling of terminal platelets. These morphological features are shown in scanning electron micrographs of a naturally occuring vermiculite. ?? 1969.

  13. A satellite-based analysis of temporal dynamics in tropospheric nitrogen dioxide levels over large urban agglomerations worldwide

    NASA Astrophysics Data System (ADS)

    Schneider, Philipp; van der A, Ronald; Valdebenito, Alvaro

    2014-05-01

    Satellite observations allow for a consistent perspective on tropospheric nitrogen dioxide at a global scale and their operational status facilitates studies on multi-annual to decadal temporal dynamics. Utilizing close to a decade of data from the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) and the Ozone Monitoring Instrument (OMI) sensors, we present in this contribution a global analysis of the temporal dynamics in tropospheric nitrogen dioxide over the worlds' major urban agglomerations during the last 10 years. The results indicate that while levels of nitrogen dioxide have been slowly declining in most areas of the United States and Europe over the last decade, very rapid increases in tropospheric nitrogen dioxide can be observed over many megacities and other large urban agglomerations throughout most of Asia, often with highly significant trends. Particularly in Eastern China, increases of 10 to 20 percent per year are quite widespread. Some of the large urban agglomerations with the most rapid increase in nitrogen dioxide pollution are Dhaka in Bangladesh, Kabul in Afghanistan, and Tianjin in China, and these are investigated in more detail. An inter-comparison of trends derived separately from SCIAMACHY and OMI shows that in terms of spatial patterns the resulting trends agree quite well between the two instruments, particularly in the more polluted areas. However, at the individual grid cell level substantial differences can be found. In addition, the satellite-based trends in tropospheric nitrogen dioxide levels were compared to those obtained from the European Monitoring and Evaluation Programme (EMEP) chemical transport model over the same time period, and furthermore sampling the model at the same time of day as the satellite overpass, thus eliminating the impact of the distinct diurnal cycle of nitrogen dioxide. While generally a good correspondence in the trends has been found between the two data sources

  14. Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees

    PubMed Central

    Silva, Lucas C. R.; Salamanca-Jimenez, Alveiro; Doane, Timothy A.; Horwath, William R.

    2015-01-01

    The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases (13CO2 and 15NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the 13CO2 pulse, assimilation and transport of the 15NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history. PMID:26294035

  15. Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

    PubMed

    Silva, Lucas C R; Salamanca-Jimenez, Alveiro; Doane, Timothy A; Horwath, William R

    2015-01-01

    The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history. PMID:26294035

  16. Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

    PubMed

    Silva, Lucas C R; Salamanca-Jimenez, Alveiro; Doane, Timothy A; Horwath, William R

    2015-08-21

    The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

  17. Final report on international comparison CCQM-K74: Nitrogen dioxide, 10 µmol/mol

    NASA Astrophysics Data System (ADS)

    Flores, Edgar; Idrees, Faraz; Moussay, Philippe; Viallon, Joële; Wielgosz, Robert; Fernández, Teresa; Ramírez, Sergio; Rojo, Andrés; Shinji, Uehara; Waldén, Jari; Sega, Michela; Sang-Hyub, Oh; Macé, Tatiana; Couret, Cedric; Qiao, Han; Smeulders, Damian; Guenther, Franklin R.; Thorn, William J., III; Tshilongo, James; Godwill Ntsasa, Napo; Štovcík, Viliam; Valková, Miroslava; Konopelko, Leonid; Gromova, Elena; Nieuwenkamp, Gerard; Wessel, Rob M.; Milton, Martin; Harling, Alice; Vargha, Gergely; Tuma, Dirk; Kohl, Anka; Schulz, Gert

    2012-01-01

    There is a high international priority attached to activities which reduce NOx in the atmosphere. The current level of permitted emissions is typically between 50 µmol/mol and 100 µmol/mol, but lower values are expected in the future. Currently, ambient air quality monitoring regulations also require the measurement of NOx mole fractions as low as 0.2 µmol/mol. The production of accurate standards at these levels of mole fractions requires either dilution of a stable higher concentration gas standard or production by a dynamic technique, for example one based on permeation tubes. The CCQM-K74 key comparison was designed to evaluate the level of comparability of National Metrology Institutes' measurement capabilities and standards for nitrogen dioxide (NO2) at a nominal mole fraction of 10 µmol/mol. The measurements of this key comparison took place from June 2009 to May 2010. Seventeen laboratories took part in this comparison coordinated by the BIPM and VSL. The key comparison reference value was based on BIPM measurement results, and the standard measurement uncertainty of the reference value was 0.042 µmol/mol. This key comparison demonstrated that the results of the majority of the participants agreed within limits of ±3% relative to the reference value. The results of only one laboratory lay significantly outside these limits. Likewise this comparison made clear that a full interpretation of the results of the comparison needed to take into account the presence of nitric acid (in the range 100 nmol/mol to 350 nmol/mol) in the cylinders circulated as part of the comparison, as well as the possible presence of nitric acid in the primary standards used by participating laboratories. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the

  18. Measurement of formaldehyde, nitrogen dioxide, and sulfur dioxide at Whiteface Mountain using a dual tunable diode laser system

    NASA Astrophysics Data System (ADS)

    Li, Y. Q.; Demerjian, K. L.; Zahniser, M. S.; Nelson, D. D.; McManus, J. B.; Herndon, S. C.

    2004-08-01

    An application of a dual tunable diode laser absorption spectrometer (TDLAS) to ambient measurements of formaldehyde (HCHO), nitrogen dioxide (NO2) and sulfur dioxide (SO2) is described. During the PM2.5 Technology Assessment and Characterization Study-New York (PMTACS-NY) 2002 intensive field campaign at Whiteface Mountain, New York, a dual TDLAS was deployed during a field instrument comparison study along with five other state-of-the-art trace gas measurement techniques. Prior to the field study, a thorough laboratory characterization of the instrument was undertaken to establish the optimum operational conditions including the selection of absorption features and the implementation of continuous laser frequency locking and rapid background subtraction. The Allan variance method was used to determine the optimal background subtraction cycle and to evaluate instrument performance. During the field campaign, measurements of HCHO, NO2 and SO2 were made by the TDLAS with the measurement precisions (1-min time interval, 1σ) of 80 ppt, 30 ppt and 40 ppt, respectively. The HCHO time series indicated a high variability of HCHO concentrations ranging from below the detection limit to 5 ppbv. The diurnal cycle of HCHO measurements showed higher concentrations during the late afternoon and early morning hours. The measured NO2 concentrations varied from less than the detection limit to the maximum of 25 ppbv. Broad NO2 plumes from long-distance transport of air masses and as well as high spikes from local pollution sources were observed during the campaign. The measured SO2 results also show high variability with the average concentration of 0.75 ± 0.95 ppbv (1σ).

  19. Ambient nitrogen dioxide and sulfur dioxide concentrations over a region of natural gas production, Northeastern British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Islam, S. M. Nazrul; Jackson, Peter L.; Aherne, Julian

    2016-10-01

    The Peace River district of Northeastern British Columbia, Canada is a region of natural gas production that has undergone rapid expansion since 2005. In order to assess air quality implications, Willems badge passive diffusive samplers were deployed for six two-week exposure periods between August and November 2013, at 24 sites across the region to assess the ambient concentration of nitrogen dioxide (NO2) and sulfur dioxide (SO2). The highest concentrations of both species (NO2: 9.1 ppb, SO2: 1.91 ppb) during the whole study period (except the 1st exposure period), were observed in Taylor (Site 14), which is consistent with its location near major industrial sources. Emissions from industrial activities, and their interaction with meteorology and topography, result in variations in atmospheric dispersion that can increase air pollution concentrations in Taylor. However, relatively high concentrations of NO2 were also observed near the center of Chetwynd (site F20), indicating the importance of urban emissions sources in the region as well. Observations of both species from the other study sites document the spatial variability and show relatively high concentrations near Fort St. John and Dawson Creek, where unconventional oil and gas development activities are quite high. Although a few sites in Northeastern British Columbia recorded elevated concentrations of NO2 and SO2 during this investigation, the concentrations over the three-month period were well below provincial annual ambient air quality objectives. Nonetheless, given the limited observations in the region, and the accelerated importance of unconventional oil and gas extraction in meeting energy demands, it is imperative that monitoring networks are established to further assess the potential for elevated ambient concentrations associated with industrial emissions sources in the Peace River region.

  20. A Passive Sampler for Determination of Nitrogen Dioxide in Ambient Air

    NASA Astrophysics Data System (ADS)

    Xiao, Dan; Lin, Lianzhi; Yuan, Hongyan; Choi, Martin M. F.; Chan, Winghong

    2005-08-01

    This article describes the use of a passive sampler for detecting and collecting nitrogen dioxide, NO 2 , in ambient air. This device is based on microporous PTFE membranes that allow air samples to diffuse through and subsequently react with an absorbing reagent solution. The absorbance value of this reagent is proportional to the NO 2 concentration in ambient air. It has been successfully applied to determine the NO 2 concentrations in various sampling sites. The sampler is simple, lightweight, and inexpensive. The experiments are suitable for college students in analytical chemistry and environmental studies.

  1. A practical alternative to chemiluminescence-based detection of nitrogen dioxide: cavity attenuated phase shift spectroscopy.

    PubMed

    Kebabian, Paul L; Wood, Ezra C; Herndon, Scott C; Freedman, Andrew

    2008-08-15

    We present results obtained from a greatly improved version of a previously reported nitrogen dioxide monitor (Anal Chem. 2005, 77, 724-728) that utilizes cavity attenuated phase shift spectroscopy (CAPS). The sensor, which detects the optical absorption of nitrogen dioxide within a 20 nm bandpass centered at 440 nm, comprises a blue light emitting diode, an enclosed stainless steel measurement cell (26 cm length) incorporating a resonant optical cavity of near-confocal design and a vacuum photodiode detector. An analog heterodyne detection scheme is used to measure the phase shift in the waveform of the modulated light transmitted through the cell induced by the presence of nitrogen dioxide within the cell. The sensor, which operates at atmospheric pressure, fits into a 19 in.-rack-mounted instrumentation box, weighs 10 kg, and utilizes 70 W of electrical power with pump included. The sensor response to nitrogen dioxide (calculated as the cotangent of the phase shift) is demonstrated to be linear (r2 > 0.9999) within +/- 1 ppb over a range of 0-320 ppb (by volume). The device exhibits a detection limit (3sigma precision) of less than 60 parts per trillion (0.060 ppb) with 10 s integration, a value derived from measurements at NO2 concentration levels of both 0 and 20 ppb; the detection limit improves as the integration time is increased to several hundred seconds. The observed baseline drift is less than +/- 0.5 ppb overthe course of a month. An intercomparison of measurements of ambient NO2 concentrations over several days using this sensor with a quantum cascade laser-based infrared absorption spectrometer and a standard chemiluminescence-based NOx analyzer is presented. The data from the CAPS sensor are highly correlated (r2 > 0.99) with the other two instruments. The absolute agreement between the CAPS and each of the two other instruments is within the expected statistical noise associated with the infrared laser-based absorption spectrometer (+/- 0.3 ppb

  2. Ultrasensitive and selective nitrogen dioxide sensor based on self-assembled graphene/polymer composite nanofibers.

    PubMed

    Yuan, Wenjing; Huang, Liang; Zhou, Qinqin; Shi, Gaoquan

    2014-10-01

    Reduced graphene oxide (rGO) sheets were self-assembled onto the surfaces of electrospun polymer nanofibers to form an ultrathin coating. These rGO/polymer composite nanofibers were used to fabricate nitrogen dioxide (NO2) sensor. This sensor can be performed at room temperature, and it exhibited a high sensitivity of 1.03 ppm(-1) with excellent selectivity and good reversibility. Furthermore, the limit of detection was experimentally measured to be as low as 150 ppb, and this value is much lower than the threshold exposure limit proposed by American Conference of Governmental Industrial Hygienists (200 ppb). PMID:25208097

  3. Liquid crystal-based sensors for selective and quantitative detection of nitrogen dioxide

    PubMed Central

    Sen, Avijit; Kupcho, Kurt A.; Grinwald, Bart A.; VanTreeck, Heidi J.; Acharya, Bharat R.

    2013-01-01

    A highly sensitive nitrogen dioxide (NO2) sensor based on orientational transition of a thin film of liquid crystal (LC) supported on a gold surface is reported. Transport of NO2 molecules through the LC film to the LC-gold interface induces an orientation transition in the LC film. The dynamic behavior of the sensor response exhibits a concentration-dependent response rate that is employed to generate an algorithm for quantitative determination of unknown concentrations. Sensitive, selective and reversible detection with minimal effects of environmental fluctuations suggest that these sensors can be used for quantitative NO2 detection for a number of applications. PMID:23526230

  4. Description of data on the Nimbus 7 LIMS map archive tape: Water vapor and nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Haggard, Kenneth V.; Marshall, B. T.; Kurzeja, Robert J.; Remsberg, Ellis E.; Russell, James M., III

    1988-01-01

    Described is the process by which the analysis of the Limb Infrared Monitor of the Stratosphere (LIMS) experiment data were used to produce estimates of synoptic maps of water vapor and nitrogen dioxide. In addition to a detailed description of the analysis procedure, also discussed are several interesting features in the data which are used to demonstrate how the analysis procedure produced the final maps and how one can estimate the uncertainties in the maps. In addition, features in the analysis are noted that would influence how one might use, or interpret, the results. These include subjects such as smoothing and the interpretation of wave components.

  5. Liquid crystal-based sensors for selective and quantitative detection of nitrogen dioxide.

    PubMed

    Sen, Avijit; Kupcho, Kurt A; Grinwald, Bart A; Vantreeck, Heidi J; Acharya, Bharat R

    2013-03-01

    A highly sensitive nitrogen dioxide (NO2) sensor based on orientational transition of a thin film of liquid crystal (LC) supported on a gold surface is reported. Transport of NO2 molecules through the LC film to the LC-gold interface induces an orientation transition in the LC film. The dynamic behavior of the sensor response exhibits a concentration-dependent response rate that is employed to generate an algorithm for quantitative determination of unknown concentrations. Sensitive, selective and reversible detection with minimal effects of environmental fluctuations suggest that these sensors can be used for quantitative NO2 detection for a number of applications. PMID:23526230

  6. Review of the US Consumer Product Safety Commission's health effects and exposure assessment documents on nitrogen dioxide. Report of the Clean Air Scientific Advisory Committee. Final report

    SciTech Connect

    Not Available

    1988-05-09

    At the request of the Consumer Product Safety Commission, the Clean Air Scientific Advisory Committee conducted a review on the potential health hazards associated with exposure to 0.1 to 1.0 ppm nitrogen dioxide generated by unvented indoor combustion sources. The committee concluded that: (1) repeated peak exposures at concentrations of 0.3 ppm of nitrogen dioxide may cause health effects in some individuals; (2) the population groups that appear most sensitive to nitrogen dioxide exposure include children, chronic bronchitics, asthmatics, and individuals with emphysema; and (3) the most direct evidence regarding lung damage associated with nitrogen dioxide is obtained from animal studies.

  7. Chemical modification of a porous silicon surface induced by nitrogen dioxide adsorption.

    PubMed

    Sharov, Constantine S; Konstantinova, Elizaveta A; Osminkina, Lyubov A; Timoshenko, Victor Yu; Kashkarov, Pavel K

    2005-03-17

    The effect of gaseous and liquid nitrogen dioxide on the composition and electronic properties of porous silicon (PS) is investigated by means of optical spectroscopy and electron paramagnetic resonance. It is detected that the interaction process is weak and strong forms of chemisorption on the PS surface, and the process may be regarded as an actual chemical reaction between PS and NO(2). It is found that NO(2) adsorption consists in forming different surface nitrogen-containing molecular groups and dangling bonds of Si atoms (P(b)-centers) as well as in oxidizing and hydrating the PS surface. Also observed are the formation of ionic complexes of P(b)-centers with NO(2) molecules and the generation of free charge carriers (holes) in the volume of silicon nanocrystals forming PS. PMID:16851549

  8. Nitrogen Dioxide Trend over the United States: the View from the Ground, the View from Space

    NASA Technical Reports Server (NTRS)

    Lamsal, Lok N.; Duncan, Bryan N.; Yoshida, Yasuko; Krotkov, Nickolay A.

    2014-01-01

    Emissions of nitrogen oxides (NOx) are decreasing over the US due to environmental policies and technological change. We use observations of tropospheric nitrogen dioxide (NO2) columns from the Ozone Monitoring Instrument (OMI) satellite instrument and surface NO2 in-situ measurements from the air quality system (AQS) to quantify the trends, and to establish the relationship between the trends in tropospheric column and surface concentration. Both observations show substantial downward trends from 2005 to 2013, with an average reduction of 35 percent according to OMI and 38 percent according to AQS. The annual reduction rates are largest in 2005-2009: -6.2 percent per year and -7 percent per year observed by OMI and AQS, respectively. We examine various factors affecting the estimated trend in OMI NO2 columns and in-situ NO2 observations. An improved understanding of trend offers valuable insights about effectiveness of emission reduction regulations on state and federal level.

  9. Tuning the Carbon Dioxide Absorption in Amino Acid Ionic Liquids.

    PubMed

    Firaha, Dzmitry S; Kirchner, Barbara

    2016-07-01

    One of the possible solutions to prevent global climate change is the reduction of CO2 emissions, which is highly desired for the sustainable development of our society. In this work, the chemical absorption of carbon dioxide in amino acid ionic liquids was studied through first-principles methods. The use of readily accessible and biodegradable amino acids as building blocks for ionic liquids makes them highly promising replacements for the widely applied hazardous aqueous solutions of amines. A detailed insight into the reaction mechanism of the CO2 absorption was obtained through state-of-the-art theoretical methods. This allowed us to determine the reason for the specific CO2 capacities found experimentally. Moreover, we have also conducted a theoretical design of ionic liquids to provide valuable insights into the precise tuning of the energetic and kinetic parameters of the CO2 absorption.

  10. Tuning the Carbon Dioxide Absorption in Amino Acid Ionic Liquids.

    PubMed

    Firaha, Dzmitry S; Kirchner, Barbara

    2016-07-01

    One of the possible solutions to prevent global climate change is the reduction of CO2 emissions, which is highly desired for the sustainable development of our society. In this work, the chemical absorption of carbon dioxide in amino acid ionic liquids was studied through first-principles methods. The use of readily accessible and biodegradable amino acids as building blocks for ionic liquids makes them highly promising replacements for the widely applied hazardous aqueous solutions of amines. A detailed insight into the reaction mechanism of the CO2 absorption was obtained through state-of-the-art theoretical methods. This allowed us to determine the reason for the specific CO2 capacities found experimentally. Moreover, we have also conducted a theoretical design of ionic liquids to provide valuable insights into the precise tuning of the energetic and kinetic parameters of the CO2 absorption. PMID:27214652

  11. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media

    PubMed Central

    Moret, Séverine; Dyson, Paul J.; Laurenczy, Gábor

    2014-01-01

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °C, 0.2 M formic acid can be obtained under 200 bar, however, in DMSO the same catalyst affords 1.9 M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes. PMID:24886955

  12. Interference of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1975-01-01

    The interference of small concentrations (less than 4 percent by volume) of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence was measured. The sample gas consisted primarily of nitrogen, with less than 100 parts per million concentration of nitric oxide, and with small concentrations of oxygen, carbon dioxide, and water vapor added. Results obtained under these conditions indicate that although oxygen does not measurably affect the analysis for nitric oxide, the presence of carbon dioxide and water vapor causes the indicated nitric oxide concentration to be too low. An interference factor - defined as the percentage change in indicated nitric oxide concentration (relative to the true nitric oxide concentration) divided by the percent interfering gas present - was determined for carbon dioxide to be -0.60 + or - 0.04 and for water vapor to be -2.1 + or - 0.3.

  13. Ambient Fine Particulate Matter, Nitrogen Dioxide, and Term Birth Weight in New York, New York

    PubMed Central

    Savitz, David A.; Bobb, Jennifer F.; Carr, Jessie L.; Clougherty, Jane E.; Dominici, Francesca; Elston, Beth; Ito, Kazuhiko; Ross, Zev; Yee, Michelle; Matte, Thomas D.

    2014-01-01

    Building on a unique exposure assessment project in New York, New York, we examined the relationship of particulate matter with aerodynamic diameter less than 2.5 μm and nitrogen dioxide with birth weight, restricting the population to term births to nonsmokers, along with other restrictions, to isolate the potential impact of air pollution on growth. We included 252,967 births in 2008–2010 identified in vital records, and we assigned exposure at the residential location by using validated models that accounted for spatial and temporal factors. Estimates of association were adjusted for individual and contextual sociodemographic characteristics and season, using linear mixed models to quantify the predicted change in birth weight in grams related to increasing pollution levels. Adjusted estimates for particulate matter with aerodynamic diameter less than 2.5 μm indicated that for each 10-µg/m3 increase in exposure, birth weights declined by 18.4, 10.5, 29.7, and 48.4 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. Adjusted estimates for nitrogen dioxide indicated that for each 10-ppb increase in exposure, birth weights declined by 14.2, 15.9, 18.0, and 18.0 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. These results strongly support the association of urban air pollution exposure with reduced fetal growth. PMID:24218031

  14. Ambient fine particulate matter, nitrogen dioxide, and term birth weight in New York, New York.

    PubMed

    Savitz, David A; Bobb, Jennifer F; Carr, Jessie L; Clougherty, Jane E; Dominici, Francesca; Elston, Beth; Ito, Kazuhiko; Ross, Zev; Yee, Michelle; Matte, Thomas D

    2014-02-15

    Building on a unique exposure assessment project in New York, New York, we examined the relationship of particulate matter with aerodynamic diameter less than 2.5 μm and nitrogen dioxide with birth weight, restricting the population to term births to nonsmokers, along with other restrictions, to isolate the potential impact of air pollution on growth. We included 252,967 births in 2008-2010 identified in vital records, and we assigned exposure at the residential location by using validated models that accounted for spatial and temporal factors. Estimates of association were adjusted for individual and contextual sociodemographic characteristics and season, using linear mixed models to quantify the predicted change in birth weight in grams related to increasing pollution levels. Adjusted estimates for particulate matter with aerodynamic diameter less than 2.5 μm indicated that for each 10-µg/m(3) increase in exposure, birth weights declined by 18.4, 10.5, 29.7, and 48.4 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. Adjusted estimates for nitrogen dioxide indicated that for each 10-ppb increase in exposure, birth weights declined by 14.2, 15.9, 18.0, and 18.0 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. These results strongly support the association of urban air pollution exposure with reduced fetal growth. PMID:24218031

  15. Ambient fine particulate matter, nitrogen dioxide, and term birth weight in New York, New York.

    PubMed

    Savitz, David A; Bobb, Jennifer F; Carr, Jessie L; Clougherty, Jane E; Dominici, Francesca; Elston, Beth; Ito, Kazuhiko; Ross, Zev; Yee, Michelle; Matte, Thomas D

    2014-02-15

    Building on a unique exposure assessment project in New York, New York, we examined the relationship of particulate matter with aerodynamic diameter less than 2.5 μm and nitrogen dioxide with birth weight, restricting the population to term births to nonsmokers, along with other restrictions, to isolate the potential impact of air pollution on growth. We included 252,967 births in 2008-2010 identified in vital records, and we assigned exposure at the residential location by using validated models that accounted for spatial and temporal factors. Estimates of association were adjusted for individual and contextual sociodemographic characteristics and season, using linear mixed models to quantify the predicted change in birth weight in grams related to increasing pollution levels. Adjusted estimates for particulate matter with aerodynamic diameter less than 2.5 μm indicated that for each 10-µg/m(3) increase in exposure, birth weights declined by 18.4, 10.5, 29.7, and 48.4 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. Adjusted estimates for nitrogen dioxide indicated that for each 10-ppb increase in exposure, birth weights declined by 14.2, 15.9, 18.0, and 18.0 g for exposures in the first, second, and third trimesters and for the total pregnancy, respectively. These results strongly support the association of urban air pollution exposure with reduced fetal growth.

  16. Improved retrieval of nitrogen dioxide (NO2) column densities by means of MKIV Brewer spectrophotometers

    NASA Astrophysics Data System (ADS)

    Diémoz, H.; Siani, A. M.; Redondas, A.; Savastiouk, V.; McElroy, C. T.

    2014-07-01

    A new algorithm to retrieve nitrogen dioxide (NO2) column densities using MKIV Brewer spectrophotometers is described. The method includes several improvements, such as a more recent spectroscopic dataset, the reduction of the measurement noise and interferences by other atmospheric species and instrumental settings, and a better determination of the air mass enhancement factors. The technique was tested during an ad-hoc calibration campaign at the high-altitude site of Izaña (Tenerife, Spain) and provided results compatible to those obtained from a spectrometer associated to the Network for the Detection of Atmospheric Composition Change (NDACC), with deviations of less than 0.02 DU. To determine the extraterrestrial constant, an easily implementable generalisation of the standard Langley technique was developed which takes into account the daytime linear drift of nitrogen dioxide due to the photochemistry. Estimates obtained from different observation geometries, by collecting the light from either the sun or the zenith sky, were found to be comparable within the measurement uncertainty. The latter was thoroughly determined by using a Monte Carlo technique. Finally, a method to retrieve additional products such as the degree of linear polarisation of the zenith sky and the oxygen dimer optical depth is presented. The new algorithm is backward-compatible, thus allowing for the reprocessing of historical datasets.

  17. Sorption of methane, ethane, propane, butane, carbon dioxide, and nitrogen on kerogen

    NASA Astrophysics Data System (ADS)

    Pribylov, A. A.; Skibitskaya, N. A.; Zekel', L. A.

    2014-06-01

    Sorption isotherms of nitrogen, methane (in the pressure range of 0.1-40 MPa), ethane (0.1-3.7MPa), propane (0.01-1 MPa), butane (0.01-0.2 MPa), and carbon dioxide (0.1-6 MPa) are measured on two adsorbents with kerogen contents of 16 and 75% at temperatures of 303, 323, 343 K. Adsorption volumes are calculated for all adsorption systems using two independent methods. The BET technique is used to determine the surface area values of the two adsorbents on the basis of sorption data for ethane, propane, butane, and carbon dioxide. The initial and isosteric adheat of sorption values are calculated on the basis of sorption isotherms of ethane, propane, butane, carbon dioxide measured at three temperatures. It is found from comparing the dependences of isosteric heat of sorption on the two adsorbents that molecules of the above gases diffuse into its bulk (adsorbent 2) in addition to sorbing on the outside surface formed by kerogen molecules, while sorption of the same gases on the rock (adsorbent 1) is similar to sorption on a smooth hard adsorbent surface.

  18. Failure of ozone and nitrogen dioxide to enhance lung tumor development in hamsters. Research report, January 1989-March 1992

    SciTech Connect

    Witschi, H.; Breider, M.A.; Schuller, H.M.

    1993-09-01

    The authors tested the hypothesis that ozone and nitrogen dioxide modulate the development of respiratory tract tumors, in particular neuroendocrine cell tumors, in Syrian golden hamsters. The animals received subcutaneous injections of the carcinogen N-diethylnitrosamine (20 mg/kg) twice a week while being exposed continuously to an atmosphere of 0.8 parts per million (ppm) of ozone or 15 ppm nitrogen dioxide. Animals were killed 16 weeks or 24 to 32 weeks after the beginning of the treatment. For positive controls, animals were treated with N-diethylnitrosamine and exposed to 65% oxygen. Ozone delayed the incidence of tumors in the lung periphery. Ozone also seemed to mitigate development of hepatoxic lesions mediated by N-diethylnitrosamine. The role of ozone and nitrogen dioxide as possible additional risks in the pathogenesis of lung cancer in animals continues to remain uncertain.

  19. Modeling uncertainties for tropospheric nitrogen dioxide columns affecting satellite-based inverse modeling of nitrogen oxides emissions

    NASA Astrophysics Data System (ADS)

    Lin, J.-T.; Liu, Z.; Zhang, Q.; Liu, H.; Mao, J.; Zhuang, G.

    2012-12-01

    Errors in chemical transport models (CTMs) interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2) and emissions of nitrogen oxides (NOx) have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI) to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 18% in July and 8% in January, the most important factor being modified uptake of the hydroperoxyl radical (HO2) on aerosols. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitude

  20. Nitration of benzo(a)pyrene adsorbed on coal fly ash particles by nitrogen dioxide: role of thermal activation

    SciTech Connect

    Robert L. Kristovich; Prabir K. Dutta

    2005-09-15

    Nitration of benzo(a)pyrene (BaP) by nitrogen dioxide (NO{sub 2}) adsorbed on the surface of thermally activated coal fly ash and model aluminosilicate particles led to the formation of nitrobenzo(2)pyrenes as verified by extraction and gas chromatography/mass spectrometry (GC/MS). Temperatures of up to 500{sup o}C were used. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was utilized to follow the nitration reaction on the surface of zeolite Y. Nitrobenzo(a)pyrene formation was observed along with the formation of nitrous acid and nitrate species. The formation of the BaP radical cation was also observed on thermally activated aluminosilicate particles by electron spin resonance (ESR) spectroscopy. On the basis of GC/MS, DRIFTS, and ESR spectroscopy results, a mechanism of nitration involving intermediate BaP radical cations generated on thermally activated aluminosilicate particles is proposed. These observations have led to the hypothesis that nitration of adsorbed polyaromatic hydrocarbons on coal fly ash by reaction with nitrogen oxides can occur in the smokestack, but with the aging of the fly ash particles, the extent of the nitration reaction will be diminished. 52 refs., 6 figs., 3 tabs.

  1. Effects of boric acid and borax on titanium dioxide genotoxicity.

    PubMed

    Turkez, Hasan

    2008-07-01

    Titanium dioxide (TiO(2)) is a potential carcinogenic/mutagenic agent although it is used in many areas including medical industries and cosmetics. Boron (as boric acid and borax) has also well-described biological effects and therapeutic benefits. In a previous study, sister-chromatid exchanges (SCEs) and micronuclei (MN) rates were assessed in control and TiO(2)-treated (1, 2, 3, 5, 7.5 and 10 microm) human whole blood cultures. The results showed that the rates of SCE (at 2, 3, 5, 7.5 and 10 microm) and MN (at 5, 7.5 and 10 microm) formation in peripheral lymphocytes were increased significantly by TiO(2) compared with the controls. The present study also investigated the genetic effects of boric acid and borax (2.5, 5 and 10 microm) on cultures with and without TiO(2) addition. No significant increase in SCE and MN frequencies were observed at all concentrations of boron compounds. However, TiO(2)-induced SCE and MN could be reduced significantly by the presence of boric acid and borax. In conclusion, this study indicated for the first time that boric acid and borax led to an increased resistance of DNA to damage induced by TiO(2).

  2. Differential assimilation of nitrogen dioxide by 70 taxa of roadside trees at an urban pollution level.

    PubMed

    Takahashi, Misa; Higaki, Asa; Nohno, Masako; Kamada, Mitsunori; Okamura, Yukio; Matsui, Kunio; Kitani, Shigekazu; Morikawa, Hiromichi

    2005-11-01

    In order to screen for the best species for mitigating nitrogen dioxide (NO2) by plants at urban levels, we investigated assimilation of nitrogen dioxide by 70 taxa of woody plants that are mostly utilized as roadside trees. They were fumigated with 15N-labeled NO2 at 0.1 microl l(-1) for 8h, and the amount of reduced nitrogen derived from NO2 (in mg Ng(-1) dry weight) in the leaves (designated NO2 assimilation capability hereafter) were determined. Data were analyzed in the comparison with the previously reported ones obtained at 4 microl l(-1) NO2. Among the 70 taxa, the value of NO2 assimilation capability differed by a factor of 122 between the highest (Prunus yedoensis; 0.061) and the lowest (Cryptomeria japonica; 0.0005). Based on the analysis of NO2 assimilation capability values at 0.1 and 4 micro l(-1) NO2, the 70 taxa of woody plants appeared to be classified into four types; those of high NO2 assimilation and high NO2 resistance, those of high NO2 assimilation but low NO2 resistance, those of low NO2 assimilation and low NO2 resistance, and those of low NO2 assimilation but high NO2 resistance. The first, second, third and fourth types include 13, 11, 35 and 11 taxa, respectively. The broad-leaf deciduous trees may have advantages of high biomass and fast growth as compared with woody plants of other habits. Thus, four broad-leaf deciduous species, Robinia pseudo-acacia, Sophora japonica, Populus nigra and Prunus lannesiana, were concluded here to be the best phytoremediators for the urban air. PMID:16219499

  3. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  4. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  5. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  6. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  7. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  8. Enhancement in the photocatalytic nature of nitrogen-doped PVD-grown titanium dioxide thin films

    SciTech Connect

    Tavares, C. J.; Marques, S. M.; Viseu, T.; Teixeira, V.; Carneiro, J. O.; Alves, E.; Barradas, N. P.; Munnik, F.; Girardeau, T.; Riviere, J.-P.

    2009-12-01

    Nitrogen-doped titanium dioxide semiconductor photocatalytic thin films have been deposited by unbalanced reactive magnetron physical vapor deposition on glass substrates for self-cleaning applications. In order to increase the photocatalytic efficiency of the titania coatings, it is important to enhance the catalysts absorption of light from the solar spectra. Bearing this fact in mind, a reduction in the titania semiconductor band-gap has been attempted by using nitrogen doping from a coreactive gas mixture of N{sub 2}:O{sub 2} during the titanium sputtering process. Rutherford backscattering spectroscopy was used in order to assess the composition of the titania thin films, whereas heavy-ion elastic recoil detection analysis granted the evaluation of the doping level of nitrogen. X-ray photoelectron spectroscopy provided valuable information about the cation-anion binding within the semiconductor lattice. The as-deposited thin films were mostly amorphous, however, after a thermal annealing in vacuum at 500 deg. C the crystalline polymorph anatase and rutile phases have been developed, yielding an enhancement in the crystallinity. Spectroscopic ellipsometry experiments enabled the determination the refractive index of the thin films as a function of the wavelength, while from the optical transmittance it was possible to estimate the semiconductor indirect band-gap of these coatings, which has been proven to decrease as the N-doping increases. The photocatalytic performance of the titania films has been characterized by the degradation rate of an organic reactive dye under UV/visible irradiation. It has been found that for a certain critical limit of 1.19 at. % of nitrogen doping in the titania anatase crystalline lattice enhances the photocatalytic behavior of the thin films and it is in accordance with the observed semiconductor band-gap narrowing to 3.18 eV. By doping the titania lattice with nitrogen, the photocatalytic activity is enhanced under both UV and

  9. A Simple Demonstration of Carbon Dioxide Fixation and Acid Production in CAM Plants

    ERIC Educational Resources Information Center

    Walker, John R. L.; McWha, James A.

    1976-01-01

    Described is an experiment investigating carbon dioxide fixation in the dark and the diurnal rhythm of acid production in plants exhibiting Crassulacean Acid Metabolism. Included are suggestions for four further investigations. (SL)

  10. Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide

    PubMed Central

    Hutchins, David A.; Walworth, Nathan G.; Webb, Eric A.; Saito, Mak A.; Moran, Dawn; McIlvin, Matthew R.; Gale, Jasmine; Fu, Fei-Xue

    2015-01-01

    Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean. PMID:26327191

  11. Chemical vapour deposition of nitrogen-doped titanium dioxide thin films.

    PubMed

    Alexandrov, S E; Baryshnikova, M V; Filatov, L A; Shahmin, A L; Andreeva, V D

    2011-09-01

    Nitrogen-doped titanium dioxide is often considered as a promising nanomaterial for photocatalytic applications. Here we report the first results of a study of APCVD of N-doped TiO2 thin films prepared with the use of ammonia as a source of nitrogen and titanium tetraisopropoxide (TTIP) as a source of Ti and O atoms. The obtained films were analyzed with X-ray diffraction, infrared spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and ellipsometry. It was found that the film growth rate in the TTIP-NH3-Ar reaction system varied insignificantly with substrate temperature in the range of 450,..., 750 degrees C and did not exceed 4.4 nm/min. Yellow and orange layers with nitrogen content of about 7.6% were formed at the deposition temperature higher than 600 degrees C. The results of the structure analysis of the deposited films showed that addition of ammonia led to stabilization of the amorphous phase in the films. The effect of ammonia on optical and photocatalytic properties was also considered. PMID:22097568

  12. Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide

    NASA Astrophysics Data System (ADS)

    Hutchins, David A.; Walworth, Nathan G.; Webb, Eric A.; Saito, Mak A.; Moran, Dawn; McIlvin, Matthew R.; Gale, Jasmine; Fu, Fei-Xue

    2015-09-01

    Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean.

  13. Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide.

    PubMed

    Hutchins, David A; Walworth, Nathan G; Webb, Eric A; Saito, Mak A; Moran, Dawn; McIlvin, Matthew R; Gale, Jasmine; Fu, Fei-Xue

    2015-09-01

    Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean.

  14. The Cabauw Intercomparison Campaign for Nitrogen Dioxide Measuring Instruments (CINDI): Design, Execution, and Early Results

    NASA Technical Reports Server (NTRS)

    Piters, Ankie; Boersma, K.F.; Kroon, M.; Hains, J. C.; Roozendael, M. Van; Wittrock, F.; Abuhassan, N.; Adams, C.; Akrami, M.; Allaart, M. A. F.; Apituley, A.; Beirle, S.; Bergwerff, J. B.; Berkhout, A. J. C.; Brunner, D.; Cede, A.; Chong, J.; Clemer, K.; Fayt, C.; FrieB, U.; Gast, L. F. L.; Gil-Ojeda, M.; Goutail, F.; Graves, R.; Griesfeller, A.

    2012-01-01

    From June to July 2009 more than thirty different in-situ and remote sensing instruments from all over the world participated in the Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI). The campaign took place at KNMI's Cabauw Experimental Site for Atmospheric Research (CESAR) in the Netherlands. Its main objectives were to determine the accuracy of state-ofthe- art ground-based measurement techniques for the detection of atmospheric nitrogen dioxide (both in-situ and remote sensing), and to investigate their usability in satellite data validation. The expected outcomes are recommendations regarding the operation and calibration of such instruments, retrieval settings, and observation strategies for the use in ground-based networks for air quality monitoring and satellite data validation. Twenty-four optical spectrometers participated in the campaign, of which twenty-one had the capability to scan different elevation angles consecutively, the so-called Multi-axis DOAS systems, thereby collecting vertical profile information, in particular for nitrogen dioxide and aerosol. Various in-situ samplers and lidar instruments simultaneously characterized the variability of atmospheric trace gases and the physical properties of aerosol particles. A large data set of continuous measurements of these atmospheric constituents has been collected under various meteorological conditions and air pollution levels. Together with the permanent measurement capability at the CESAR site characterizing the meteorological state of the atmosphere, the CINDI campaign provided a comprehensive observational data set of atmospheric constituents in a highly polluted region of the world during summertime. First detailed comparisons performed with the CINDI data show that slant column measurements of NO2, O4 and HCHO with MAX-DOAS agree within 5 to 15%, vertical profiles of NO2 derived from several independent instruments agree within 25% of one another, and MAX

  15. The Chemical and Dynamical Responses of Ozone and Nitrogen Dioxide to the Eruption of Mt. Pinatubo

    NASA Technical Reports Server (NTRS)

    Aquila, V.; Oman, L. D.; Stolarski, R.; Douglass, A. R.

    2012-01-01

    Observations have shown that the concentration of nitrogen dioxide decreased in both hemispheres in the years following the eruption of Mt. Pinatubo. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little or no change in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the seasonal phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol.

  16. The Response of Ozone and Nitrogen Dioxide to the Eruption of Mt. Pinatubo

    NASA Technical Reports Server (NTRS)

    Aquila, Valentina; Oman, Luke D.; Stolarski, R.; Douglass, A. R.; Newman, P. A.

    2012-01-01

    Observations have shown that the global mass of nitrogen dioxide decreased in both hemispheres in the year following the eruption of Mt. Pinatubo. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little change and even a small increase in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol.

  17. The Response of Ozone and Nitrogen Dioxide to the Eruption of Mount Pinatubo

    NASA Technical Reports Server (NTRS)

    Aquila. Valentina; Oman, Luke D.; Stolarsk, Richard S.; Douglass, Anne R.; Newman, Paul A.

    2012-01-01

    Observations have shown that the global mass of nitrogen dioxide decreased in both hemispheres in the year following the eruption of Mt. Pinatubo, indicating an enhanced heterogeneous chemistry. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little change in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol.

  18. Influence of photolysis on multispectral photoacoustic measurement of nitrogen dioxide concentration.

    PubMed

    Tian, Guoxun; Moosmüller, Hans; Arnott, W Patrick

    2013-09-01

    Multispectral photoacoustic instruments are commonly used to measure aerosol and nitrogen dioxide (NO2) light absorption coefficients to determine the radiation budget of the atmosphere. Here a new photoacoustic system is developed to explore the effect of photolysis on the measured signal in a multispectral photoacoustic spectrometer In this system, a 405-nm laser is used primarily as light source for photolysis. Additionally, a well-overlapped 532-nm laser, modulated at the resonant frequency of the photoacoustic instrument, is used to probe the NO2 concentration. As a result, the photolysis effect at 405 nm can be observed by the photoacoustic instrument through the 532-nm laser. This work determines an 11% reduction of the photoacoustic signal caused by the photolysis effect for typical conditions, which needs to be taken into account when calibrating multispectral photoacoustic spectrometers with NO2. PMID:24151684

  19. LPG ammonia and nitrogen dioxide gas sensing properties of nanostructured polypyrrole thin film

    NASA Astrophysics Data System (ADS)

    Bagul, Sagar B.; Upadhye, Deepak S.; Sharma, Ramphal

    2016-05-01

    Nanostructured Polypyrrole thin film was synthesized by easy and economic chemical oxidative polymerization technique on glass at room temperature. The prepared thin film of Polypyrrole was characterized by optical absorbance study by UV-visible spectroscopy and electrical study by I-V measurement system. The optical absorbance spectrum of Polypyrrole shows two fundamental peaks in region of 420 and 890 nm, which confirms the formation of Polypyrrole on glass substrate. The I-V graph of nanostructured Polypyrrole represents the Ohmic nature. Furthermore, the thin film of Polypyrrole was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents spherical nanostructured morphology of Polypyrrole on glass substrate. In order to investigate gas sensing properties, 100 ppm of LPG, Ammonia and Nitrogen Dioxide were injected in the gas chamber and magnitude of resistance has been recorded as a function of time in second. It was observed that nanostructured Polypyrrole thin film shows good sensing behavior at room temperature.

  20. Responses of susceptible subpopulations to nitrogen dioxide. Research report, June 1983-January 1988

    SciTech Connect

    Morrow, P.E.; Utell, M.J.

    1989-02-01

    Symptom responses and changes in pulmonary function were investigated in people with asthma or chronic obstructive pulmonary disease (COPD) exposed to 0.3 ppm nitrogen dioxide (NO{sub 2}) for four hours. Nonrespiratory-impaired (normal) subjects of comparable ages constituted the control groups. All exposures included periods of exercise and pulmonary function measurements. No significant symptomatic or physiological responses to NO{sub 2} could be detected in either the young or elderly control group. The asthmatic group did not manifest significant reductions in lung function after exposure to 0.3 ppm NO{sub 2}, compared to their preexposure baseline data or to their responses after a comparable four-hour exposure to air. During light exercise, subjects with COPD were progressively responsive to 0.3 ppm NO{sub 2}. Subgroup analyses within the asthmatic, COPD, and elderly normal subject groups and intergroup comparisons yielded significant findings and associations.

  1. Nitrogen dioxide monitoring with an automatic DOAS station at Terra Nova Bay, Antarctica

    NASA Astrophysics Data System (ADS)

    Ravegnani, Fabrizio; Kostadinov, Ivan K.; Giovanelli, Giorgio

    1998-08-01

    During the last few years UV-Vis spectrometers were developed at the FISBAT Institute and are used for application of differential optical absorption spectroscopy method to detect many atmospheric trace gases playing important roles in the stratospheric chemistry. After several test both in laboratory and in Antarctic region, one of the spectrometers, called GASCOD2/2, was modified in collaboration with ENEA for unattended and automatic measurement in extreme high-latitude environment. The instrument was installed in December 1995 in the Italian Station at Terra Nova Bay. The aim of this research is to study the dentrification processes during the formation of the so-called ozone hole over the Antarctic region. The preliminary results for the first year of nitrogen dioxide measurement are presented and discussed.

  2. Susceptibility to virus infection with exposure to nitrogen dioxide. Research report, January 1984-July 1987

    SciTech Connect

    Kulle, T.J.; Clements, M.L.

    1988-01-01

    The interaction between nitrogen dioxide (NO/sub 2/) exposure and human susceptibility to respiratory virus infection was investigated in a placebo-controlled, randomized, blinded trial conducted in an environmentally controlled research chamber. Healthy, nonsmoking volunteers, 18 to 35 years old, who were seronegative to influenza A/Korea/82 (H/sub 3/N/sub 2/) virus, breathed either filtered air or NO/sub 2/ for two hours a day for three consecutive days. Live, attenuated cold-adapted influenza A/Korea/82 reassortant virus was administered intranasally to all subjects after the second day of exposure. No adverse changes in pulmonary function or nonspecific airway reaction to methacholine were observed after NO/sub 2/ exposure, virus infection, or both. Although the differences were not statistically significant, the groups exposed to NO/sub 2/ in year 3 became infected more often (91%) than those exposed only to air (71%).

  3. Foliage plants for indoor removal of the primary combustion gases carbon monoxide and nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.; Mesick, H. H.

    1985-01-01

    Foliage plants were evaluated for their ability to sorb carbon monoxide and nitrogen dioxide, the two primary gases produced during the combustion of fossil fuels and tobacco. The spider plant (Chlorophytum elatum var. vittatum) could sorb 2.86 micrograms CO/sq cm leaf surface in a 6 h photoperiod. The golden pothos (Scindapsus aureus) sorbed 0.98 micrograms CO/sq cm leaf surface in the same time period. In a system with the spider plant, greater than or equal to 99 percent of an initial concentration of 47 ppm NO2 could be removed in 6 h from a void volume of approximately 0.35 cu m. One spider plant potted in a 3.8 liter container can sorb 3300 micrograms CO and effect the removal of 8500 micrograms NO2/hour, recognizing the fact that a significant fraction of NO2 at high concentrations will be lost by surface sorption, dissolving in moisture, etc.

  4. Effects of nitrogen dioxide on alveolar epithelial barrier properties. Research report, September 1983-January 1987

    SciTech Connect

    Crandall, E.D.; Cheek, J.M.; Shaw, M.E.; Postlethwait, E.M.

    1987-10-01

    This study used primary cultures of rat Type II pneumocytes to investigate if, and how, nitrogen dioxide (NO/sub 2/) alters the permeability of the alveolar epithelia. Susceptibility of cells to NO/sub 2/ appears to depend on the nutrient media of the cells, with a 10-fold difference observed between minimum essential medium (MEM) and MEM supplemented with Ham's F12 media. No protective effect was observed when the antioxidant, vitamin E, was added to the media. Bioelectric studies were conducted on cells cultured on a porous substrate. Exposure to 20 ppm NO/sub 2/ caused significant reductions in tissue resistance but not in short-circuit current. It was concluded that NO/sub 2/ primarily affects epithelial active and passive transport via altered tight junctional pathways that result from damage to paracellular tight junctions or, possibly, to transcellular transport membrane pumps. The authors suggest that free-radical formation causes the damage observed.

  5. Differential responses of Arabidopsis thaliana accessions to atmospheric nitrogen dioxide at ambient concentrations

    PubMed Central

    Takahashi, Misa; Morikawa, Hiromichi

    2014-01-01

    To better understand the response of plants to atmospheric nitrogen dioxide (NO2), we investigated biomass accumulation in 3 accessions of Arabidopsis thaliana: C24, Columbia (Col-0), and Landsberg erecta (Ler). Plants were grown in NO2-free air for 1 week after sowing, followed by 3 (Col-0 and Ler) to 4 (C24) weeks in air with or without NO2 (10 or 50 ppb). NO2 treatment increased the biomass of all 3 accessions to varying extents. Treatment with 10 ppb NO2 increased shoot biomass in C24, Col-0, and Ler by 3.2-, 1.4-, and 2.3-fold, respectively, compared with control. Treatment with 50 ppb gave similar increases, except in C24 (2.7-fold). The physiological, evolutionary, and genetic significance of these results are discussed below. PMID:24675109

  6. Nitrogen dioxide at an ambient level improves the capability of kenaf (Hibiscus cannabinus) to decontaminate cadmium.

    PubMed

    Takahashi, Misa; Adam, Suaad E H; Konaka, Daisuke; Morikawa, Hiromichi

    2008-01-01

    As reported previously, atmospheric nitrogen dioxide (NO2) at an ambient level increased plant size and the contents of cell constituents. We investigated this effect of atmospheric NO2 on decontamination of cadmium (Cd) by kenaf (Hibiscus cannabinus). Seventeen-day-old seedlings of kenaf were grown in air either with NO2 or without NO2. (Plants were exposed to 100 +/- 50 ppb NO2 for 10 d under irrigation of 0.1% Hyponex supplemented with 20 microM CdCl2.) Plants were then harvested and the biomass of stems, leaves, and roots, as well as the content of Cd in the organs, was determined. The stem and root biomass per plant were 1.25-1.27-fold greater in +NO2 plants than in -NO2 plants. The Cd content per stem was more than 30% greater in +NO2 plants than in -NO2 plants.

  7. CHARACTERIZATION OF A SPATIAL GRADIENT OF NITROGEN DIOXIDE ACROSS A UNITED STATES-MEXICO BORDER CITY DURING WINTER

    EPA Science Inventory

    A gradient of ambient nitrogen dioxide (NO2) concentration is demonstrated across metropolitan El Paso, Texas (USA), a city located on the international border between the United States and Mexico. Integrated measurements of NO2 were collected over seven days at 20 elementary sc...

  8. Effect of Same-day Sequential Exposure to Nitrogen Dioxide and Ozone on Cardiac and Ventilatory Function in Mice

    EPA Science Inventory

    This study examines the cardiac and ventilatory effects of sequential exposure to nitrogen dioxide and then ozone. The data show that mice exposed to both gases have increased arrhythmia and breathing changes not observed in the other groups. Although the mechanisms underlying ai...

  9. Role of photoexcited nitrogen dioxide chemistry on ozone formation and emission control strategy over the Pearl River Delta, China

    EPA Science Inventory

    A new hydroxyl radical formation pathway via photo-excited nitrogen dioxide chemistry is incorporated into a chemistry-only box model as well as a 3D air quality model to examine its potential role on ozone formation and emission control strategy over the Pearl River Delta region...

  10. ASSOCIATION OF INDOOR NITROGEN DIOXIDE WITH RESPIRATORY SYSMPTOMS IN CHILDREN: THE EFFECT OF MEASUREMENT ERROR CORRECTION WITH MULTIPLE SURROGATES

    EPA Science Inventory

    In 1991, Neas et al. reported that indoor nitrogen dioxide (N02), a by-product of high-temperature combustion, was significantly associated with lower respiratory symptoms among a cohort of 1159 white children ages 7-11 years in six US cities studied from 1983-1988. For each 15 p...

  11. Review of the Primary National Ambient Air Quality Standards for Nitrogen Dioxide: Risk and Exposure Assessment Planning Document

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) is conducting a review of the air quality criteria and the primary (health-based) national ambient air quality standards (NAAQS) for nitrogen dioxide (NO2). The major phases of the process for reviewing NAAQS include the following: (...

  12. 40 CFR Appendix F to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (NO2) are measured indirectly by photometrically measuring the light intensity, at wavelengths greater... Chemiluminescence Measurement of Nitrogen Dioxide,” EPA-E600/4-75-003 (Available in draft form from the United States Environmental Protection Agency, Department E (MD-76), Environmental Monitoring and...

  13. Influence of experimental pulmonary emphysema on the toxicological effects from inhaled nitrogen dioxide and diesel exhaust

    SciTech Connect

    Mauderly, J.L.; Bice, D.E.; Cheng, Y.S.; Gillett, N.A.; Henderson, R.F.; Pickrell, J.A.; Wolff, R.K. )

    1989-10-01

    This project examined the influence of preexisting, experimentally induced pulmonary emphysema on the adverse health effects in rats of chronic inhalation exposure to either nitrogen dioxide or automotive diesel-engine exhaust. Previous reports indicated that humans with chronic lung disease were among those most severely affected by episodic exposures to high concentrations of airborne toxicants. There were no previous reports comparing the effects of chronic inhalation exposure to components of automotive emissions in emphysematous and normal animals. The hypothesis tested in this project was that rats with preexisting pulmonary emphysema were more susceptible than rats with normal lungs to the adverse effects of the toxicant exposures. Young adult rats were housed continuously in inhalation exposure chambers and exposed seven hours per day, five days per week, for 24 months to nitrogen dioxide at 9.5 parts per million (ppm)2, or to diesel exhaust at 3.5 mg soot/m3, or to clean air as control animals. These concentrations were selected to produce mild, but distinct, effects in rats with normal lungs. Pulmonary emphysema was induced in one-half of the rats by intratracheal instillation of the proteolytic enzyme elastase six weeks before the toxicant exposures began. Health effects were evaluated after 12, 18, and 24 months of exposure. The measurements included respiratory function, clearance of inhaled radiolabeled particles, pulmonary immune responses to instilled antigen, biochemistry and cytology of airway fluid, total lung collagen, histopathology, lung morphometry, and lung burdens of diesel soot. The significance of influences of emphysema and toxicant exposure, and interactions between influences of the two treatments, were evaluated by analysis of variance.

  14. Nitrogen Dioxide Sterilization in Low-Resource Environments: A Feasibility Study

    PubMed Central

    Avasthi, Trisha; Trilling, Ariel

    2015-01-01

    Access to sterilization is a critical need for global healthcare, as it is one of the prerequisites for safe surgical care. Lack of sterilization capability has driven up healthcare infection rates as well as limited access to healthcare, especially in low-resource environments. Sterilization technology has for the most part been static and none of the established sterilization methods has been so far successfully adapted for use in low-resource environments on a large scale. It is evident that healthcare facilities in low-resource settings require reliable, deployable, durable, affordable, easily operable sterilization equipment that can operate independently of scarce resources. Recently commercialized nitrogen dioxide (NO2) sterilization technology was analyzed and adapted into a form factor suitable for use in low-resource environments. Lab testing was conducted in microbiological testing facilities simulating low-resource environments and in accordance with the requirements of the international sterilization standard ANSI/AAMI/ISO 14937 to assess effectiveness of the device and process. The feasibility of a portable sterilizer based on nitrogen dioxide has been demonstrated, showing that sterilization of medical instruments can occur in a form factor suitable for use in low-resource environments. If developed and deployed, NO2 sterilization technology will have the twin benefits of reducing healthcare acquired infections and limiting a major constraint for access to surgical care on a global scale. Additional benefits are achieved in reducing costs and biohazard waste generated by current health care initiatives that rely primarily on disposable kits, increasing the effectiveness and outreach of these initiatives. PMID:26098905

  15. Housing characteristics and indoor concentrations of nitrogen dioxide and formaldehyde in Quebec City, Canada.

    PubMed

    Gilbert, Nicolas L; Gauvin, Denis; Guay, Mireille; Héroux, Marie-Eve; Dupuis, Geneviève; Legris, Michel; Chan, Cecilia C; Dietz, Russell N; Lévesque, Benoît

    2006-09-01

    Concentrations of nitrogen dioxide and formaldehyde were determined in a study of 96 homes in Quebec City, Canada, between January and April 2005. In addition, relative humidity, temperature, and air change rates were measured in homes, and housing characteristics were documented through a questionnaire to occupants. Half of the homes had ventilation rates below 7.5 L/s person. Nitrogen dioxide (NO2) and formaldehyde concentrations ranged from 3.3 to 29.1 microg/m3 (geometric mean 8.3 microg/m3) and from 9.6 to 90.0 microg/m3 (geometric mean of 29.5 microg/m3), respectively. The housing characteristics documented in the study explained approximately half of the variance of NO2 and formaldehyde. NO2 concentrations in homes were positively correlated with air change rates (indicating a significant contribution of outdoor sources to indoor levels) and were significantly elevated in homes equipped with gas stoves and, to a lesser extent, in homes with gas heating systems. Formaldehyde concentrations were negatively correlated with air change rates and were significantly elevated in homes heated by electrical systems, in those with new wooden or melamine furniture purchased in the previous 12 months, and in those where painting or varnishing had been done in the sampled room in the previous 12 months. Results did not indicate any significant contribution of indoor combustion sources, including wood-burning appliances, to indoor levels of formaldehyde. These results suggest that formaldehyde concentrations in Quebec City homes are caused primarily by off-gassing, and that increasing air change rates in homes could reduce exposure to this compound. More generally, our findings confirm the influence of housing characteristics on indoor concentrations of NO2 and formaldehyde.

  16. [Occurrence of carbon monoxide, carbon dioxide and nitrogen oxides during the use of gas stoves].

    PubMed

    Prescher, K E

    1982-01-01

    The concentrations of carbon monoxide, carbon dioxide, nitrogen monoxide and nitrogen dioxide arising from gas burning have been measured under experimental and field conditions. In the test room propane, butane and town-gas have been burned, whereas in the apartments investigated only town-gas has been used. The most important influence on the concentration of the four substances arises from the changes in the burning conditions of the flame. Laboratory experiments have been carried out in the test room with open flames and with an aluminum block or a kettle on the flame. The following results have been obtained: (a) for CO the lowest concentration is obtained with open flames irrespective of the type of gas burned. Higher concentrations have been found with aluminum blocks, whereas the highest concentrations were associated with the use of kettles and pots, (b) the experimental conditions have only a small influence on the CO2 concentration, (c) NO concentrations are influenced by the gas type and by the experimental conditions. They are low with kettles but high with open flames, (d) NO2 concentrations are less influenced by the experimental conditions than are NO concentrations. The results of more than 1000 paired determinations of NO2 in kitchen and other rooms are presented. The concentrations which have been measured using diffusion tubes according to Palmes which were exposed for 48 h, were highest in kitchens of dwellings fully equipped with gas devices (heating, cooking, warming water). The mean value of the concentrations was about 50 micrograms/m3, whereas the mean for dwellings without any gas device has been found to be lower than 20 micrograms/m3. PMID:6820854

  17. Nitrogen dioxide vapor penetration of chlorobutyl rubber SCAPE under operational conditions

    NASA Technical Reports Server (NTRS)

    Schehl, T. A.; Beall, T. W.

    1980-01-01

    Operational self contained atmospheric protective ensembles (SCAPE suits) and fabric from the suits were subjected to a series of tests designed to determine the amount of exposure a wearer of the suit would receive if a spill of the hypergolic oxidizer nitrogen tetroxide (N2O4) should occur nearby. The results of these tests show that a wearer of a "stock" SCAPE suit equipped with a standard liquid air pack, if exposed to a spill resulting in a 26 percent increase of oxidizer in the surrounding atmosphere, will experiment no detectable concentration of nitrogen dioxide (NO2) inside the suit for 15 minutes. Thereafter, the NO2 concentration within the suit will increase for 35 minutes at a rate of 0.07 ppm per minute and then at a gradually decreasing rate until an equilibrium concentration of 3.4 ppm is attained after 100 minutes. Momentary increases of as much as 1.6 ppm can be expected if the wearer were to rise quickly from a squatting position, but the additional NO2 would be dissipated within three minutes. The effect of liquid and vapor N2O4 and of liquid monomethylhydrazine on permeation rates and tensile strength of the SCAPE suit fabric was also investigated.

  18. Passive Chemiresistor Sensor Based on Iron (II) Phthalocyanine Thin Films for Monitoring of Nitrogen Dioxide

    NASA Astrophysics Data System (ADS)

    Shu, John Hungjen

    In this dissertation, an alternate, new approach was investigated to produce a nonreversible, passive, iron (II) phthalocyanine (FePc) thin film sensor that does not require continuous power for operation. The sensor was manufactured using standard microelectronics fabrication procedures, with emphasis on low cost and sensor consistency. The sensor substrate consists of a gold interdigitated electrode pattern deposited on an oxidized silicon or quartz wafer. The FePc thin film is then vacuum sublimed over the interdigitated electrodes to form the finalized sensor. Different thicknesses and morphologies of FePc thin films were fabricated. Once sensor fabrication was accomplished, the general response, temperature dependence, concentration dependence, specificity, and longevity of FePc thin film sensors were investigated. To evaluate general sensor reponse, sensors were exposed to 100 ppm nitrogen dioxide in nitrogen, with a flow rate of 0.25 liters per minute (L/min), at the temperatures of -46, 20, and 71 °C. For each case, the resistance of the sensor decreased exponentially as a function of exposure duration and reached saturation within 25 minutes. The resistance decrease was measured to be four, three, and two orders of magnitude for the exposure temperatures of -46, 20, and 71 .C respectively. In these experiments, sub-zero temperature detection of nitrogen dioxide with FePc thin films was reported for the first time. It was found that the response at -46 °C was greater than at 20 or 71 °C. To evaluate temperature dependence, sensors were thermal cycled in the range of -50 to 80 °C, first under ultra-high purity nitrogen gas at 0.25 L/min, and then under 100 ppm nitrogen dioxide gas at 0.25 L/min. Intrinsic FePc film conductivity was measured by thermal cycling sensors under nitrogen gas. Extrinsic FePc film conductivity was measured by thermal cycling sensors under nitrogen dioxide gas. Results from these tests indicated that the temperature dependence of

  19. Quantifying the impact of nitric oxide calibration gas mixture oxidation on reported nitrogen dioxide concentrations

    NASA Astrophysics Data System (ADS)

    Sweeney, Bryan P.; Quincey, Paul G.; Green, David; Fuller, Gary W.

    2015-03-01

    Chemiluminescent analysers for measuring nitric oxide (NO) and nitrogen dioxide (NO2) in ambient air are generally calibrated with certified gas standard cylinders of NO in nitrogen. Verification of the NOx and NO amount fractions has been carried out on many such 'on-site' calibration cylinders at air quality monitoring stations. These measurements indicate that significant numbers of these gas mixtures have become somewhat degraded, with several percent of the NO oxidised to NO2. The effect of not compensating for this degradation on reported concentrations is discussed. If such degradation is not quantified and corrected for, there will be a systematic under-reporting of NO2 concentrations, which, due to the non-linearity of the effect, could reduce high reported NO2 concentrations at kerbside sites by around 20%. This could significantly reduce the number of reported exceedances of the NO2 limit value at such sites, compared to results obtained where there is no degradation of the NO cylinder.

  20. Exchange of nitrogen dioxide (NO2) between plants and the atmosphere under laboratory and field conditions

    NASA Astrophysics Data System (ADS)

    Breuninger, C.; Meixner, F. X.; Thielmann, A.; Kuhn, U.; Dindorf, T.; Kesselmeier, J.

    2012-04-01

    Nitric oxide (NO), nitrogen dioxide (NO2), often denoted as nitrogen oxides (NOx), and ozone (O3) are considered as most important compounds in atmospheric chemistry. In remote areas NOx concentration is related to biological activities of soils and vegetation. The emitted NOx will not entirely be subject of long range transport through the atmosphere. Aside oxidation of NO2 by the OH radical (forming HNO3), a considerable part of it is removed from the atmosphere through the uptake of NO2 by plants. The exchange depends on stomatal activity and on NO2 concentrations in ambient air. It is known that NO2 uptake by plants represents a large NO2 sink, but the magnitude and the NO2 compensation point concentration are still under discussion. Our dynamic chamber system allows exchange measurements of NO2 under field conditions (uncontrolled) as well as studies under controlled laboratory conditions including fumigation experiments. For NO2 detection we used a highly NO2 specific blue light converter (photolytic converter) with subsequent chemiluminescence analysis of the generated NO. Furthermore, as the exchange of NO2 is a complex interaction of transport, chemistry and plant physiology, in our field experiments we determined fluxes of NO, NO2, O3, CO2 and H2O. For a better knowledge of compensation point values for the bi-directional NO2 exchange we investigated a primary representative of conifers, Picea abies, under field and laboratory conditions, and re-analyzed older field data of the deciduous tree Quercus robur.

  1. Undoped and doped poly(tetraphenylbenzidine) as sensitive material for an impedimetric nitrogen dioxide gas dosimeter

    SciTech Connect

    Marr, I.; Moos, R.; Neumann, K.; Thelakkat, M.

    2014-09-29

    This article presents a nitrogen dioxide (NO{sub 2}) detecting gas dosimeter based on poly(tetraphenylbenzidine) poly(TPD) as nitrogen oxide (NO{sub x}) sensitive layer. Gas dosimeters are suitable devices to determine reliably low levels of analytes over a long period of time. During NO{sub x} exposure, the analyte molecules are accumulated irreversibly in the sensing layer of the dosimeter enhancing the conductivity of the hole conducting poly(TPD), which can be measured by impedance spectroscopy. Due to their possibility for low cost production by simple printing techniques and very good physical, photochemical, and electrochemical properties, poly(TPD)s are suitable for application in gas dosimeters operated at room temperature. We studied the effect of doping with a Co(III)-complex in combination with a conducting salt on the dosimeter behavior. Compared to the undoped material, a strong influence of the doping can be observed: the conductivity of the sensing material increases significantly, the noise of the signal decreases and an unwanted recovery of the sensor signal can be prevented, leading to a NO{sub x} detection limit <10 ppm.

  2. Undoped and doped poly(tetraphenylbenzidine) as sensitive material for an impedimetric nitrogen dioxide gas dosimeter

    NASA Astrophysics Data System (ADS)

    Marr, I.; Neumann, K.; Thelakkat, M.; Moos, R.

    2014-09-01

    This article presents a nitrogen dioxide (NO2) detecting gas dosimeter based on poly(tetraphenylbenzidine) poly(TPD) as nitrogen oxide (NOx) sensitive layer. Gas dosimeters are suitable devices to determine reliably low levels of analytes over a long period of time. During NOx exposure, the analyte molecules are accumulated irreversibly in the sensing layer of the dosimeter enhancing the conductivity of the hole conducting poly(TPD), which can be measured by impedance spectroscopy. Due to their possibility for low cost production by simple printing techniques and very good physical, photochemical, and electrochemical properties, poly(TPD)s are suitable for application in gas dosimeters operated at room temperature. We studied the effect of doping with a Co(III)-complex in combination with a conducting salt on the dosimeter behavior. Compared to the undoped material, a strong influence of the doping can be observed: the conductivity of the sensing material increases significantly, the noise of the signal decreases and an unwanted recovery of the sensor signal can be prevented, leading to a NOx detection limit <10 ppm.

  3. XPS study of nitrogen dioxide adsorption on metal oxide particle surfaces under different environmental conditions.

    PubMed

    Baltrusaitis, Jonas; Jayaweera, Pradeep M; Grassian, Vicki H

    2009-10-01

    The adsorption of nitrogen dioxide on gamma aluminium oxide (gamma-Al(2)O(3)) and alpha iron oxide (alpha-Fe(2)O(3)) particle surfaces under various conditions of relative humidity, presence of molecular oxygen and UV light has been investigated. X-Ray photoelectron spectroscopy (XPS) is used to monitor the different surface species that form under these environmental conditions. Adsorption of NO(2) on aluminum oxide particle surfaces results primarily in the formation of surface nitrate, NO(3)(-) with an oxidation state of +5, as indicated by a peak with binding energy of 407.3 eV in the N1s region. An additional minority species, sensitive to the presence of relative humidity and molecular oxygen, is also observed in the N1s region with lower binding energy of 405.9 eV. This peak is assigned to a surface species in the +4 oxidation state. When irradiated with UV light, other species form on the surface. These surface-bound photochemical products all have lower binding energy, between 400 and 402 eV, indicating reduced nitrogen species in the range of N oxidations states spanning +1 to -1. Co-adsorbed water decreases the amount of these reduced surface-bound products while the presence of molecular oxygen completely suppresses the formation of all reduced nitrogen species on aluminum oxide particle surfaces. For NO(2) on iron oxide particle surfaces, photoreduction is enhanced relative to gamma-Al(2)O(3) and surface bound photoreduced species are observed under all environmental conditions. Complementing the experimental data, N1s core electron binding energies (CEBEs) were calculated using DFT for a number of nitrogen-containing species in the gas phase and adsorbed on an Al(8)O(12) cluster. A range of CEBEs is calculated for various nitrogen species in different adsorption modes and oxidation states. These calculated values are discussed in light of the peaks observed in the XPS N1s region and the possible species that form following NO(2) adsorption and

  4. Molecular mechanisms of nitrogen dioxide induced epithelial injury in the lung.

    PubMed

    Persinger, Rebecca L; Poynter, Matthew E; Ckless, Karna; Janssen-Heininger, Yvonne M W

    2002-01-01

    The lung can be exposed to a variety of reactive nitrogen intermediates through the inhalation of environmental oxidants and those produced during inflammation. Reactive nitrogen species (RNS) include, nitrogen dioxide (.NO2) and peroxynitrite (ONOO-). Classically known as a major component of both indoor and outdoor air pollution, .NO2 is a toxic free radical gas. .NO2 can also be formed during inflammation by the decomposition of ONOO- or through peroxidase-catalyzed reactions. Due to their reactive nature, RNS may play an important role in disease pathology. Depending on the dose and the duration of administration, .NO, has been documented to cause pulmonary injury in both animal and human studies. Injury to the lung epithelial cells following exposure to .NO2 is characterized by airway denudation followed by compensatory proliferation. The persistent injury and repair process may contribute to airway remodeling, including the development of fibrosis. To better understand the signaling pathways involved in epithelial cell death by .NO2 or otherRNS, we routinely expose cells in culture to continuous gas-phase .NO2. Studies using the .NO2 exposure system revealed that lung epithelial cell death occurs in a density dependent manner. In wound healing experiments, .NO2 induced cell death is limited to cells localized in the leading edge of the wound. Importantly, .NO2-induced death does not appear to be dependent on oxidative stress per se. Potential cell signaling mechanisms will be discussed, which include the mitogen activated protein kinase, c-Jun N-terminal Kinase and the Fas/Fas ligand pathways. During periods of epithelial loss and regeneration that occur in diseases such as asthma or during lung development, epithelial cells in the lung may be uniquely susceptible to death. Understanding the molecular mechanisms of epithelial cell death associated with the exposure to .NO2 will be important in designing therapeutics aimed at protecting the lung from

  5. Associations of Cough Prevalence with Ambient Polycyclic Aromatic Hydrocarbons, Nitrogen and Sulphur Dioxide: A Longitudinal Study

    PubMed Central

    Anyenda, Enoch Olando; Higashi, Tomomi; Kambayashi, Yasuhiro; Nguyen, Thao Thi Thu; Michigami, Yoshimasa; Fujimura, Masaki; Hara, Johsuke; Tsujiguchi, Hiromasa; Kitaoka, Masami; Asakura, Hiroki; Hori, Daisuke; Yamada, Yohei; Hayashi, Koichiro; Hayakawa, Kazuichi; Nakamura, Hiroyuki

    2016-01-01

    Information on potential cough triggers including environmental irritants is vital for successful management of chronic cough in patients. We investigated the relationship between ambient levels of particulate polycyclic aromatic hydrocarbons (PAH), nitrogen dioxide (NO2) and sulphur dioxide (SO2) exposures with cough prevalence. Eighty-three adult patients, who had been physician diagnosed with at least asthma, cough variant asthma and/or atopic cough, were divided into asthma and non-asthma groups. They recorded daily cough symptoms during 4 January–30 June 2011 study period while daily samples of total suspended particles were simultaneously collected by use of glass fiber filters and the particulate PAH content determined by high performance liquid chromatography coupled with a fluorescence detector. Ambient concentrations of NO2 and SO2 were obtained from a local monitoring site. Logistic regression models using generalized estimating equations were used to determine population-averaged estimates of association between cough prevalence and ambient pollutant exposures for the two groups. Fully adjusted odds ratios from single pollutant models were 1.083 (95% confidence interval (CI): 1.029, 1.140) and 1.097 (95% CI: 1.016, 1.185) per 0.57 ng/m3 for lag2 PAH exposure, while only for asthma group had significant associations with NO2 and SO2 exposures for both lag2 and lag02. Similar associations were observed in multipollutant models. This finding suggests that ambient PAH, NO2, and SO2 exposure even at low levels is related to cough prevalence in adult chronic cough patients and may be considered as aggravating factor during clinical management of the condition. PMID:27517941

  6. Associations of Cough Prevalence with Ambient Polycyclic Aromatic Hydrocarbons, Nitrogen and Sulphur Dioxide: A Longitudinal Study.

    PubMed

    Anyenda, Enoch Olando; Higashi, Tomomi; Kambayashi, Yasuhiro; Nguyen, Thao Thi Thu; Michigami, Yoshimasa; Fujimura, Masaki; Hara, Johsuke; Tsujiguchi, Hiromasa; Kitaoka, Masami; Asakura, Hiroki; Hori, Daisuke; Yamada, Yohei; Hayashi, Koichiro; Hayakawa, Kazuichi; Nakamura, Hiroyuki

    2016-01-01

    Information on potential cough triggers including environmental irritants is vital for successful management of chronic cough in patients. We investigated the relationship between ambient levels of particulate polycyclic aromatic hydrocarbons (PAH), nitrogen dioxide (NO₂) and sulphur dioxide (SO₂) exposures with cough prevalence. Eighty-three adult patients, who had been physician diagnosed with at least asthma, cough variant asthma and/or atopic cough, were divided into asthma and non-asthma groups. They recorded daily cough symptoms during 4 January-30 June 2011 study period while daily samples of total suspended particles were simultaneously collected by use of glass fiber filters and the particulate PAH content determined by high performance liquid chromatography coupled with a fluorescence detector. Ambient concentrations of NO₂ and SO₂ were obtained from a local monitoring site. Logistic regression models using generalized estimating equations were used to determine population-averaged estimates of association between cough prevalence and ambient pollutant exposures for the two groups. Fully adjusted odds ratios from single pollutant models were 1.083 (95% confidence interval (CI): 1.029, 1.140) and 1.097 (95% CI: 1.016, 1.185) per 0.57 ng/m³ for lag2 PAH exposure, while only for asthma group had significant associations with NO₂ and SO₂ exposures for both lag2 and lag02. Similar associations were observed in multipollutant models. This finding suggests that ambient PAH, NO₂, and SO₂ exposure even at low levels is related to cough prevalence in adult chronic cough patients and may be considered as aggravating factor during clinical management of the condition. PMID:27517941

  7. Nitrogen, tillage, and crop rotation effects on carbon dioxide and methane fluxes from irrigated cropping systems.

    PubMed

    Alluvione, Francesco; Halvorson, Ardell D; Del Grosso, Stephen J

    2009-01-01

    Long-term effects of tillage intensity, N fertilization, and crop rotation on carbon dioxide (CO(2)) and methane (CH(4)) flux from semiarid irrigated soils are poorly understood. We evaluated effects of: (i) tillage intensity [no-till (NT) and conventional moldboard plow tillage (CT)] in a continuous corn rotation; (ii) N fertilization levels [0-246 kg N ha(-1) for corn (Zea mays L.); 0 and 56 kg N ha(-1) for dry bean (Phaseolus vulgaris L.); 0 and 112 kg N ha(-1) for barley (Hordeum distichon L.)]; and (iii) crop rotation under NT soil management [corn-barley (NT-CB); continuous corn (NT-CC); corn-dry bean (NT-CDb)] on CO(2) and CH(4) flux from a clay loam soil. Carbon dioxide and CH(4) fluxes were monitored one to three times per week using vented nonsteady state closed chambers. No-till reduced (14%) growing season (154 d) cumulative CO(2) emissions relative to CT (NT: 2.08 Mg CO(2)-C ha(-1); CT: 2.41 Mg CO(2)-C ha(-1)), while N fertilization had no effect. Significantly lower (18%) growing season CO(2) fluxes were found in NT-CDb than NT-CC and NT-CB (11.4, 13.2 and 13.9 kg CO(2)-C ha(-1)d(-1) respectively). Growing season CH(4) emissions were higher in NT (20.2 g CH(4) ha(-1)) than in CT (1.2 g CH(4) ha(-1)). Nitrogen fertilization and cropping rotation did not affect CH(4) flux. Implementation of NT for 7 yr with no N fertilization was not adequate for restoring the CH(4) oxidation capacity of this clay loam soil relative to CT plowed and fertilized soil.

  8. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    PubMed

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid.

  9. HALOACETONITRILES VS. REGULATED HALOACETIC ACIDS: ARE NITROGEN CONTAINING DBPS MORE TOXIC?

    EPA Science Inventory

    Haloacetonitriles (HANs) are toxic nitrogenous drinking water disinfection by-products (N-DBPs) and are observed with chlorine, chloramine, or chlorine dioxide disinfection. Using microplate-based Chinese hamster ovary (CHO) cell assays for chronic cytotoxicity and acute genotoxi...

  10. Area-level socioeconomic deprivation, nitrogen dioxide exposure, and term birth weight in New York City

    PubMed Central

    Shmool, Jessie LC; Bobb, Jennifer F; Ito, Kazuhiko; Elston, Beth; Savitz, David A; Ross, Zev; Matte, Thomas D; Johnson, Sarah; Dominici, Francesca; Clougherty, Jane E

    2015-01-01

    Numerous studies have linked air pollution with adverse birth outcomes, but relatively few have examined differential associations across the socioeconomic gradient. To evaluate interaction effects of gestational nitrogen dioxide (NO2) and area-level socioeconomic deprivation on fetal growth, we used: 1) highly spatially-resolved air pollution data from the New York City Community Air Survey (NYCCAS); and 2) spatially-stratified principle component analysis of census variables previously associated with birth outcomes to define area-level deprivation. New York City (NYC) hospital birth records for years 2008–2010 were restricted to full-term, singleton births to non-smoking mothers (n = 243,853). We used generalized additive mixed models to examine the potentially non-linear interaction of nitrogen dioxide (NO2) and deprivation categories on birth weight (and estimated linear associations, for comparison), adjusting for individual-level socio-demographic characteristics and sensitivity testing adjustment for co-pollutant exposures. Estimated NO2 exposures were highest, and most varying, among mothers residing in the most-affluent census tracts, and lowest among mothers in residing in mid-range deprivation tracts. In non-linear models, we found an inverse association between NO2 and birth weight in the least-deprived and most-deprived areas (p-values < 0.001 and 0.05, respectively) but no association in the mid-range of deprivation (p=0.8). Likewise, in linear models, a 10 ppb increase in NO2 was associated with a decrease in birth weight among mothers in the least-deprived and most-deprived areas of −16.2 g (95% CI: −21.9 to −10.5) and −11.0 g (95% CI: −22.8 to 0.9), respectively, and a non-significant change in the mid-range areas [β = 0.5 g (95% CI: −7.7 to 8.7)]. Linear slopes in the most- and least-deprived quartiles differed from the mid-range (reference group) (p-values < 0.001 and 0.09, respectively). The complex patterning in air pollution

  11. Ambient Fine Particulate Matter, Nitrogen Dioxide, and Preterm Birth in New York City

    PubMed Central

    Johnson, Sarah; Bobb, Jennifer F.; Ito, Kazuhiko; Savitz, David A.; Elston, Beth; Shmool, Jessie L.C.; Dominici, Francesca; Ross, Zev; Clougherty, Jane E.; Matte, Thomas

    2016-01-01

    Background: Recent studies have suggested associations between air pollution and various birth outcomes, but the evidence for preterm birth is mixed. Objective: We aimed to assess the relationship between air pollution and preterm birth using 2008–2010 New York City (NYC) birth certificates linked to hospital records. Methods: We analyzed 258,294 singleton births with 22–42 completed weeks gestation to nonsmoking mothers. Exposures to ambient fine particles (PM2.5) and nitrogen dioxide (NO2) during the first, second, and cumulative third trimesters within 300 m of maternal address were estimated using data from the NYC Community Air Survey and regulatory monitors. We estimated the odds ratio (OR) of spontaneous preterm (gestation < 37 weeks) births for the first- and second-trimester exposures in a logistic mixed model, and the third-trimester cumulative exposures in a discrete time survival model, adjusting for maternal characteristics and delivery hospital. Spatial and temporal components of estimated exposures were also separately analyzed. Results: PM2.5 was not significantly associated with spontaneous preterm birth. NO2 in the second trimester was negatively associated with spontaneous preterm birth in the adjusted model (OR = 0.90; 95% CI: 0.83, 0.97 per 20 ppb). Neither pollutant was significantly associated with spontaneous preterm birth based on adjusted models of temporal exposures, whereas the spatial exposures showed significantly reduced odds ratios (OR = 0.80; 95% CI: 0.67, 0.96 per 10 μg/m3 PM2.5 and 0.88; 95% CI: 0.79, 0.98 per 20 ppb NO2). Without adjustment for hospital, these negative associations were stronger. Conclusion: Neither PM2.5 nor NO2 was positively associated with spontaneous preterm delivery in NYC. Delivery hospital was an important spatial confounder. Citation: Johnson S, Bobb JF, Ito K, Savitz DA, Elston B, Shmool JL, Dominici F, Ross Z, Clougherty JE, Matte T. 2016. Ambient fine particulate matter, nitrogen dioxide, and

  12. Area-level socioeconomic deprivation, nitrogen dioxide exposure, and term birth weight in New York City.

    PubMed

    Shmool, Jessie L C; Bobb, Jennifer F; Ito, Kazuhiko; Elston, Beth; Savitz, David A; Ross, Zev; Matte, Thomas D; Johnson, Sarah; Dominici, Francesca; Clougherty, Jane E

    2015-10-01

    Numerous studies have linked air pollution with adverse birth outcomes, but relatively few have examined differential associations across the socioeconomic gradient. To evaluate interaction effects of gestational nitrogen dioxide (NO2) and area-level socioeconomic deprivation on fetal growth, we used: (1) highly spatially-resolved air pollution data from the New York City Community Air Survey (NYCCAS); and (2) spatially-stratified principle component analysis of census variables previously associated with birth outcomes to define area-level deprivation. New York City (NYC) hospital birth records for years 2008-2010 were restricted to full-term, singleton births to non-smoking mothers (n=243,853). We used generalized additive mixed models to examine the potentially non-linear interaction of nitrogen dioxide (NO2) and deprivation categories on birth weight (and estimated linear associations, for comparison), adjusting for individual-level socio-demographic characteristics and sensitivity testing adjustment for co-pollutant exposures. Estimated NO2 exposures were highest, and most varying, among mothers residing in the most-affluent census tracts, and lowest among mothers residing in mid-range deprivation tracts. In non-linear models, we found an inverse association between NO2 and birth weight in the least-deprived and most-deprived areas (p-values<0.001 and 0.05, respectively) but no association in the mid-range of deprivation (p=0.8). Likewise, in linear models, a 10 ppb increase in NO2 was associated with a decrease in birth weight among mothers in the least-deprived and most-deprived areas of -16.2g (95% CI: -21.9 to -10.5) and -11.0 g (95% CI: -22.8 to 0.9), respectively, and a non-significant change in the mid-range areas [β=0.5 g (95% CI: -7.7 to 8.7)]. Linear slopes in the most- and least-deprived quartiles differed from the mid-range (reference group) (p-values<0.001 and 0.09, respectively). The complex patterning in air pollution exposure and deprivation

  13. Area-level socioeconomic deprivation, nitrogen dioxide exposure, and term birth weight in New York City.

    PubMed

    Shmool, Jessie L C; Bobb, Jennifer F; Ito, Kazuhiko; Elston, Beth; Savitz, David A; Ross, Zev; Matte, Thomas D; Johnson, Sarah; Dominici, Francesca; Clougherty, Jane E

    2015-10-01

    Numerous studies have linked air pollution with adverse birth outcomes, but relatively few have examined differential associations across the socioeconomic gradient. To evaluate interaction effects of gestational nitrogen dioxide (NO2) and area-level socioeconomic deprivation on fetal growth, we used: (1) highly spatially-resolved air pollution data from the New York City Community Air Survey (NYCCAS); and (2) spatially-stratified principle component analysis of census variables previously associated with birth outcomes to define area-level deprivation. New York City (NYC) hospital birth records for years 2008-2010 were restricted to full-term, singleton births to non-smoking mothers (n=243,853). We used generalized additive mixed models to examine the potentially non-linear interaction of nitrogen dioxide (NO2) and deprivation categories on birth weight (and estimated linear associations, for comparison), adjusting for individual-level socio-demographic characteristics and sensitivity testing adjustment for co-pollutant exposures. Estimated NO2 exposures were highest, and most varying, among mothers residing in the most-affluent census tracts, and lowest among mothers residing in mid-range deprivation tracts. In non-linear models, we found an inverse association between NO2 and birth weight in the least-deprived and most-deprived areas (p-values<0.001 and 0.05, respectively) but no association in the mid-range of deprivation (p=0.8). Likewise, in linear models, a 10 ppb increase in NO2 was associated with a decrease in birth weight among mothers in the least-deprived and most-deprived areas of -16.2g (95% CI: -21.9 to -10.5) and -11.0 g (95% CI: -22.8 to 0.9), respectively, and a non-significant change in the mid-range areas [β=0.5 g (95% CI: -7.7 to 8.7)]. Linear slopes in the most- and least-deprived quartiles differed from the mid-range (reference group) (p-values<0.001 and 0.09, respectively). The complex patterning in air pollution exposure and deprivation

  14. Tropospheric nitrogen dioxide column retrieval from ground-based zenith-sky DOAS observations

    NASA Astrophysics Data System (ADS)

    Tack, F.; Hendrick, F.; Goutail, F.; Fayt, C.; Merlaud, A.; Pinardi, G.; Hermans, C.; Pommereau, J.-P.; Van Roozendael, M.

    2015-06-01

    We present an algorithm for retrieving tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) from ground-based zenith-sky (ZS) measurements of scattered sunlight. The method is based on a four-step approach consisting of (1) the differential optical absorption spectroscopy (DOAS) analysis of ZS radiance spectra using a fixed reference spectrum corresponding to low NO2 absorption, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total measured slant column based on stratospheric VCDs measured at sunrise and sunset, and simulation of the rapid NO2 diurnal variation, (4) the retrieval of tropospheric VCDs by dividing the resulting tropospheric slant columns by appropriate air mass factors (AMFs). These steps are fully characterized and recommendations are given for each of them. The retrieval algorithm is applied on a ZS data set acquired with a multi-axis (MAX-) DOAS instrument during the Cabauw (51.97° N, 4.93° E, sea level) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) held from 10 June to 21 July 2009 in the Netherlands. A median value of 7.9 × 1015 molec cm-2 is found for the retrieved tropospheric NO2 VCDs, with maxima up to 6.0 × 1016 molec cm-2. The error budget assessment indicates that the overall error σTVCD on the column values is less than 28%. In the case of low tropospheric contribution, σTVCD is estimated to be around 39% and is dominated by uncertainties in the determination of the residual amount in the reference spectrum. For strong tropospheric pollution events, σTVCD drops to approximately 22% with the largest uncertainties on the determination of the stratospheric NO2 abundance and tropospheric AMFs. The tropospheric VCD amounts derived from ZS observations are compared to VCDs retrieved from off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to data

  15. Tropospheric nitrogen dioxide column retrieval from ground-based zenith-sky DOAS observations

    NASA Astrophysics Data System (ADS)

    Tack, F.; Hendrick, F.; Goutail, F.; Fayt, C.; Merlaud, A.; Pinardi, G.; Hermans, C.; Pommereau, J.-P.; Van Roozendael, M.

    2015-01-01

    We present an algorithm for retrieving tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) from ground-based zenith-sky (ZS) measurements of scattered sunlight. The method is based on a four-step approach consisting of (1) the Differential Optical Absorption Spectroscopy (DOAS) analysis of ZS radiance spectra using a fixed reference spectrum corresponding to low NO2 absorption, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total measured slant column based on stratospheric VCDs measured at sunrise and sunset, and simulation of the rapid NO2 diurnal variation, (4) the retrieval of tropospheric VCDs by dividing the resulting tropospheric slant columns by appropriate air mass factors (AMFs). These steps are fully characterized and recommendations are given for each of them. The retrieval algorithm is applied on a ZS dataset acquired with a Multi-AXis (MAX-) DOAS instrument during the Cabauw (51.97° N, 4.93° E, sea level) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) held from the 10 June to the 21 July 2009 in the Netherlands. A median value of 7.9 × 1015 molec cm-2 is found for the retrieved tropospheric NO2 VCDs, with maxima up to 6.0 × 1016 molec cm-2. The error budget assessment indicates that the overall error σTVCD on the column values is less than 28%. In case of low tropospheric contribution, σTVCD is estimated to be around 39% and is dominated by uncertainties in the determination of the residual amount in the reference spectrum. For strong tropospheric pollution events, σTVCD drops to approximately 22% with the largest uncertainties on the determination of the stratospheric NO2 abundance and tropospheric AMFs. The tropospheric VCD amounts derived from ZS observations are compared to VCDs retrieved from off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to

  16. Effects of ozone and nitrogen dioxide on drinking and eating behaviors in mice

    SciTech Connect

    Umezu, T.; Suzuki, A.K.; Miura, T.; Koizumi, A. )

    1993-04-01

    Male ICR mice were exposed continuously to ozone (O3) and nitrogen dioxide (NO2) for 7 days to examine the effects on drinking and eating behaviors. Ozone at 0.1 ppm did not affect drinking and eating activities, whereas drinking activity decreased in a concentration-dependent manner to 47.7, 12.8, and 3.0% of the control value with 2-day exposures to 0.2, 0.4, and 0.8 ppm O3, respectively, and eating activity decreased to 35.2 and 8.7% of the control value at 0.4 and 0.8 ppm O3, respectively. Body weight also decreased markedly by 2.0, 4.6, and 7.5 g at 0.2, 0.4, and 0.8 ppm O3, respectively. These decrements reached a maximum on the second day of exposure. However, alterations in drinking and eating activities and body weight were transient, leading to recovery during the continuous O3 exposures. The recovery processes were dependent on the concentrations of O3. Nitrogen dioxide at 4 ppm did not affect drinking and eating activities, whereas drinking activity decreased in a concentration-dependent manner to 56.8, 8.3, and 18.7% of the control value with 2-day exposures to 6, 8, and 12 ppm NO2, respectively, and eating activity decreased markedly to 21.8 and 16.4% at 8 and 12 ppm NO2, respectively. Body weight also decreased by 2.5, 5.5, and 6.1 g at 6, 8, and 12 ppm NO2, respectively. These decrements reached a maximum on the second day of exposure. As in the O3 exposures, the decrements in drinking and eating activities and body weight were transient and recovered during the continuous exposures to NO2 depending on the concentrations of NO2. Drinking and eating activities and body weights of mice that had been previously exposed to 12 ppm NO2 for 7 days did not show changes when the mice were exposed to 0.4 ppm O3 9 days after NO2 exposure. The present study demonstrates that photochemical oxidants suppress drinking and eating behaviors in mice and that they recover thereafter under the continuous exposure conditions.

  17. The Response of Ozone and Nitrogen Dioxide to the Eruption of Mount Pinatubo at Southern and Northern Midlatitudes

    NASA Technical Reports Server (NTRS)

    Aquila, Valentina; Oman, Luke D.; Stolarski, Richard S.; Douglass, Anne R.; Newman, Paul A.

    2013-01-01

    Observations have shown that the mass of nitrogen dioxide decreased at both southern and northern midlatitudes in the year following the eruption of Mt. Pinatubo, indicating that the volcanic aerosol had enhanced nitrogen dioxide depletion via heterogeneous chemistry. In contrast, the observed ozone response showed a northern midlatitude decrease and a small southern midlatitude increase. Previous simulations that included an enhancement of heterogeneous chemistry by the volcanic aerosol but no other effect of this aerosol produce ozone decreases in both hemispheres, contrary to observations. The authors simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and Southern Hemisphere extratropical downwelling. This enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer Dobson circulation, increased Southern Hemisphere ozone via advection, counteracting the ozone depletion due to heterogeneous chemistry on the Pinatubo aerosol.

  18. Ab initio energetics, kinetics, and quantum transport characteristics of graphene nanoribbons as nanosensors for detecting nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Paulla, Kirti K.; Hassan, Ahmed J.; Knick, Cory R.; Farajian, Amir A.

    2014-03-01

    Molecules adsorption on graphene nanoribbons (GNRs) can be used to engineer and make use of their properties for applications such as energy storage and sensors. We investigate adsorption characteristics by considering nitrogen dioxide as a sample molecule for assessing nanosensor functionality of GNRs. Using ab initio modeling, energetics of various adsorption possibilities are determined and their rate constants are calculated and compared. Nonbonding and weak sp3 adsorptions at the hydrogen-terminated edges are shown to be more feasible than center adsorptions. This shows increased reactivity compared to graphene. Calculated quantum transport responses upon molecules adsorption indicate possibility of sensing extremely low nitrogen dioxide concentrations. Possible approaches for improving gas nanosensor functionality of GNRs are discussed. Reference: RSC Advances, 2013, DOI: 10.1039/c3ra46372a. This research was supported by the National Science Foundation Grant ECCS-0925939.

  19. Acousto-optic differential optical absorption spectroscopy for atmospheric measurement of nitrogen dioxide in Hong Kong.

    PubMed

    Cheng, Andrew Y S; Chan, M H

    2004-12-01

    Measurement of the atmospheric concentration of nitrogen dioxide (NO(2)) pollutant was demonstrated by differential optical absorption spectroscopy (DOAS) using a visible acousto-optic tunable filter. In a traditional spectral scanning DOAS system for atmospheric concentration monitoring, a highly stable light source is required. When the light intensity fluctuates during scanning, the concentration retrieval will be inaccurate. In order to reduce the error due to intensity fluctuations, a modified DOAS system has been developed by introducing a broadband light intensity monitoring channel. Using the measured intensity of the broadband channel as the intensity of the light source, the spectrum can be de-biased and the residual intensity variation will primarily result from atmospheric extinction. In addition, by employing the lock-in detection technique, the background light interference is also removed in the modified DOAS system. The atmospheric NO(2) concentration measurement was performed at the campus of City University of Hong Kong, and the results were compared with the concentration reported from a nearby monitoring station in Sham Shui Po, operated by the Hong Kong Environmental Protection Department.

  20. Aircraft measurements of nitrogen dioxide and peroxyacetyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Steele, H.D.; Drayton, P.J.; Hubbe, J.M.

    1999-10-01

    Fast capillary gas chromatography with luminol detection has been used to make airborne measurements of nitrogen dioxide (NO{sub 2}) and peroxyacetyl nitrate (PAN). The analysis system allows for the simultaneous measurement of NO{sub 2} and peroxyacyl nitrates (PANs) with time resolution of less than 1 min, and improvement of a factor of 4--5 over previously reported methods using electron capture detection. Data presented were taken near Pasco, Washington, in August 1997, during a test flight onboard the US Department of Energy G-1 aircraft. The authors report measurements of NO{sub 2} in the boundary layer in a paper mill plume and a plume from a grass fire, in addition to analyses for free tropospheric NO{sub 2} and PAN. Ratios of PAN/NO{sub 2} were observed to increase with altitude (decreasing temperature) and to reach values of 2--4 above the boundary layer, consistent with the thermal equilibrium of the peroxyacetyl radical and NO{sub 2} and PAN. Estimates for the peroxyacetyl radical in the continental free troposphere, calculated from this equilibrium, were found to be in the range of 10{sup 4}--10{sup 5} molecules per cubic centimeter. These results demonstrate the application of this approach for airborne measurements of NO{sub 2} and PAN in a wide range of field study scenarios.

  1. Development and application of a luminol-based nitrogen dioxide detector

    SciTech Connect

    Wendel, G.J.

    1985-01-01

    An instrument for the continuous measurement of nitrogen dioxide (NO/sub 2/) at all atmospheric concentration ranges and conditions was developed. The detector is based on the chemiluminescent reaction between 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol) and NO/sub 2/ in alkaline aqueous solution. Development included the optimization of the cell design and the solution composition. Sodium sulfite (Na/sub 2/SO/sub 3/) and methanol (CH/sub 3/OH) were added to the solution to improve sensitivity and specificity. The detector was favorably compared to two different instruments measuring NO/sub 2/ by NO + O/sub 3/ chemiluminescent and by a tunable diode laser absorption spectrometry system. The detector has demonstrated a detection limit of 30 parts-per-trillion by volume (ppt) and a frequency response of 0.3 Hz. The instrument was operated for two one-month periods on Bermuda. The purpose was to study air masses from the East Coast of the United States after transport over the ocean. Average daily values were 400 ppt with values as low as 100 ppt measured. Other field experiments involved monitoring of NO/sub 2/ in ambient air in the range of 1 to 60 parts-per-billion by volume.

  2. Revising the slant column density retrieval of nitrogen dioxide observed by the Ozone Monitoring Instrument

    NASA Astrophysics Data System (ADS)

    Marchenko, S.; Krotkov, N. A.; Lamsal, L. N.; Celarier, E. A.; Swartz, W. H.; Bucsela, E. J.

    2015-06-01

    Nitrogen dioxide retrievals from the Aura/Ozone Monitoring Instrument (OMI) have been used extensively over the past decade, particularly in the study of tropospheric air quality. Recent comparisons of OMI NO2 with independent data sets and models suggested that the OMI values of slant column density (SCD) and stratospheric vertical column density (VCD) in both the NASA OMNO2 and Royal Netherlands Meteorological Institute DOMINO products are too large, by around 10-40%. We describe a substantially revised spectral fitting algorithm, optimized for the OMI visible light spectrometer channel. The most important changes comprise a flexible adjustment of the instrumental wavelength shifts combined with iterative removal of the ring spectral features; the multistep removal of instrumental noise; iterative, sequential estimates of SCDs of the trace gases in the 402-465 nm range. These changes reduce OMI SCD(NO2) by 10-35%, bringing them much closer to SCDs retrieved from independent measurements and models. The revised SCDs, submitted to the stratosphere-troposphere separation algorithm, give tropospheric VCDs ˜10-15% smaller in polluted regions, and up to ˜30% smaller in unpolluted areas. Although the revised algorithm has been optimized specifically for the OMI NO2 retrieval, our approach could be more broadly applicable.

  3. Aircraft measurements of nitrogen dioxide and peroxyacyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Drayton, P.J.

    1997-09-01

    Peroxyacyl nitrates (PANs) and nitrogen dioxide (NO{sub 2}) are important trace gas species associated with photochemical air pollution. The PANs are in thermal equilibrium with the peroxyacetyl radical and NO{sub 2}. Because PANs are trapped peroxy radicals, they are an important indicator species of the photochemical age of an air parcel, as well as being a means of long-range transporting of NO{sub 2}, leading to the formation of regional ozone and other oxidants. Typically, PANs are measured by using a gas chromatograph with electron-capture detection (ECD). Once automated, this method has been shown to be reliable and quite sensitive, allowing the levels of PANs to be measured at low parts per trillion in the troposphere. Unfortunately, a number of other atmospheric gases also have strong ECD signals or act as inferences and limit the speed in which the analysis can be completed. Currently, the shortest analysis time for PAN is approx. 5 minutes with ECD. The authors recent examined the luminol detection of NO{sub 2} and PANs using gas capillary chromatography for rapid monitoring of these important trace gases. Analysis of the PANs (PAN, PPN, and PBN) and NO{sub 2} in one minute has been demonstrated in laboratory studies by using this approach. Reported here are modifications of this instrument for aircraft operation and preliminary results from test flights taken near Pasco, Washington in August of 1997.

  4. Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.

    PubMed

    Takahashi, Misa; Furuhashi, Takamasa; Ishikawa, Naoko; Horiguchi, Gorou; Sakamoto, Atsushi; Tsukaya, Hirokazu; Morikawa, Hiromichi

    2014-03-01

    • To gain more insight into the physiological function of nitrogen dioxide (NO₂), we investigated the effects of exogenous NO₂ on growth in Arabidopsis thaliana. • Plants were grown in air without NO₂ for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO₂. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium. • Five-week-old plants treated with 50 ppb NO₂ showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO₂ on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO₂-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO₂, but depended on the leaf developmental stage. • Collectively, these results indicated that NO₂ regulates organ growth by controlling cell proliferation and enlargement.

  5. NDSD-1000: High-resolution, high-temperature Nitrogen Dioxide Spectroscopic Databank

    NASA Astrophysics Data System (ADS)

    Lukashevskaya, A. A.; Lavrentieva, N. N.; Dudaryonok, A. C.; Perevalov, V. I.

    2016-11-01

    We present a high-resolution, high-temperature version of the Nitrogen Dioxide Spectroscopic Databank called NDSD-1000. The databank contains the line parameters (positions, intensities, self- and air-broadening coefficients, exponents of the temperature dependence of self- and air-broadening coefficients) of the principal isotopologue of NO2. The reference temperature for line intensity is 296 K and the intensity cutoff is 10-25 cm-1/molecule cm-2 at 1000 K. The broadening parameters are presented for two reference temperatures 296 K and 1000 K. The databank has 1,046,808 entries, covers five spectral regions in the 466-4776 cm-1 spectral range and is designed for temperatures up to 1000 K. The databank is based on the global modeling of the line positions and intensities performed within the framework of the method of effective operators. The parameters of the effective Hamiltonian and the effective dipole moment operator have been fitted to the observed values of the line positions and intensities collected from the literature. The broadening coefficients as well as the temperature exponents are calculated using the semi-empirical approach. The databank is useful for studying high-temperature radiative properties of NO2. NDSD-1000 is freely accessible via the internet site of V.E. Zuev Institute of Atmospheric Optics SB RAS ftp://ftp.iao.ru/pub/NDSD/.

  6. Effects of ozone and nitrogen dioxide on pulmonary function in healthy and in asthmatic adolescents

    SciTech Connect

    Koenig, J.Q.; Covert, D.S.; Marshall, S.G.; Van Belle, G.; Pierson, W.E.

    1987-11-01

    The aim of this project was to investigate whether well-characterized asthmatic adolescent subjects were more sensitive to the inhaled effects of oxidant pollutants than were well-characterized healthy adolescent subjects. Ten healthy and 10 asthmatic subjects inhaled via a mouth-piece 0.12 or 0.18 ppm of ozone (O/sub 3/) or nitrogen dioxide (NO/sub 2/) or clean air for 30 min at rest followed by 10 min during moderate exercise (32.5 L/min) on a treadmill. The following pulmonary functional values were measured before and after exposure: peak flow, total respiratory resistance (RT), maximal flow at 50 and 75% of expired VC, and FEV1. After exercise exposure to 0.18 ppm O3, statistically significant increases were seen in RT in asthmatic and healthy adolescent subjects. No consistent changes were seen in either group after NO/sub 2/ exposure. Also, no significant differences in response to oxidant pollutants between the 2 groups could be demonstrated. It was concluded that neither group was consistently sensitive to these pollutants.

  7. Contribution of indoor and outdoor nitrogen dioxide to indoor air quality of wayside shops.

    PubMed

    Shuai, Jianfei; Yang, Wonho; Ahn, Hogi; Kim, Sunshin; Lee, Seokyong; Yoon, Sung-Uk

    2013-06-01

    Indoor nitrogen dioxide (NO₂) concentration is an important factor for personal exposure despite the wide distribution of its sources. Exposure to NO₂ may produce adverse health effects. The aims of this study were to characterize the indoor air quality of wayside shops using multiple NO₂ measurements, and to estimate the contribution of outdoor NO₂ sources such as vehicle emission to indoor air quality. Daily indoor and outdoor NO₂ concentrations were measured for 21 consecutive days in wayside shops (5 convenience stores, 5 coffee shops, and 5 restaurants). Contributions of outdoor NO₂ sources to indoor air quality were calculated with penetration factors and source strength factors by indoor mass balance model in winter and summer, respectively. Most wayside shops had significant differences in indoor and outdoor NO₂ concentrations both in winter and in summer. Indoor NO₂ concentrations in restaurants were twice more than those in convenience stores and coffee shops in winter. While outdoor NO₂ contributions in indoor convenience stores and coffee shops were dominant, indoor NO₂ contributions were dominant in restaurants. These could be explained that indoor NO₂ sources such as gas range and smoking mainly affect indoor concentrations comparing to outdoor sources such as vehicle emission. The indoor mass balance model by multiple measurements suggests that quantitative contribution of outdoor air on indoor air quality might be estimated without measurements of ventilation, indoor generation and decay rate. PMID:23774657

  8. Boosting sensitivity of boron nitride nanotube (BNNT) to nitrogen dioxide by Fe encapsulation.

    PubMed

    Zhang, Yu-qing; Liu, Yue-Jie; Liu, Yan-ling; Zhao, Jing-xiang

    2014-06-01

    The pristine boron nitride nanotube (BNNT) exhibits a poor chemical reactivity to some adsorbates, thus greatly limiting its application for the gas sensor. In the present work, using density functional theory (DFT) methods, we put forward a novel strategy to enhance the sensitivity of BNNT to nitrogen dioxide (NO2) by the encapsulation of a single Fe atom inside its cavity. The results suggest that the NO2 molecule can be only physically adsorbed on the pristine BNNT with a small adsorption energy (-0.10 eV). After the inclusion of the Fe atom inside BNNT (Fe@BNNT), the interaction of NO2 molecules with this tube is significantly enhanced, leading to a transformation from the physisorption of on pristine BNNT to the current chemisorption. Interestingly, up to five NO2 molecules can be adsorbed on this encapsulated BNNT along its circumference with the average adsorption energy of -0.52 eV, corresponding to a short recovery time (6 ms). Moreover, 0.38 electrons are transferred from the Fe@BNNT to the adsorbed NO2 molecules, which is enough to induce the obvious change of its electrical conductance. Thus, we predict that the encapsulation of Fe atom inside BNNT would greatly boosts its sensitivity to NO2 molecules, indicating its potential application as NO2 sensors. PMID:24837498

  9. Sub-ppb detection of nitrogen dioxide with an external cavity quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Lewicki, Rafal; Liu, Kun; Day, Timothy; Tittel, Frank K.

    2012-01-01

    Ultra-sensitive detection of nitrogen dioxide (NO2) in the ν3 fundamental band of NO2 using Faraday Rotation Spectroscopy (FRS) based optical sensor platform is reported. The FRS technique is well suited for selective trace gas measurements of paramagnetic species including the prominent air pollutants such as NO or NO2. In this paper a widely tunable external cavity quantum cascade laser (EC-QCL) is employed as an excitation source. The available EC-QCL mode-hop free tuning range between 1600 cm-1 and 1650 cm-1 allows to access the optimum for FRS technique 441<-440 Q-branch NO2 transition at 1613.2 cm-1 with an optical power of ~135 mW. In order to improve detection sensitivity and reduce size of the sensor platform, a custom made 22.47 cm long Herriott multipass gas cell (MPC) with a total effective optical path of 10.1 m was implemented. For a MPC configured NO2 FRS sensor operating in line-scanning mode a minimum detection limit of 1.6 ppbv (1σ) and 0.15 ppb (1σ) is achieved for a 1 sec and 100 sec averaging time, respectively. Preliminary results for long term measurements of atmospheric NO2 for the FRS sensor operating at an optimal pressure of 30 Torr and magnetic field of 200 Gaussrms were demonstrated.

  10. Ozone and nitrogen dioxide ground based monitoring by zenith sky visible spectrometry in Arctic and Antarctic

    NASA Technical Reports Server (NTRS)

    Pommereau, J. P.; Goutail, F.

    1988-01-01

    Unattended diode array spectrometers have been designed for ground based stratospheric trace species monitoring by zenith sky visible spectrometry. Measurements are performed with a 1.0 nm resolution between 290 nm and 590 nm in order to allow simultaneous evaluations of column densities of ozone, nitrogen dioxide. Field tests have shown that the species can be monitored with a precision of + or - 2 Dobson for the first and + or - 2.10 to the 15th mol/sq cm for the second, although the absolute accuracy of the method is limited by the error of the estimation of the atmospheric optical path of the scattered light. Two identical instruments were set up in January 1988, one in Antarctica at Dumont d'Urville (66 S, 140 E) to be operated all year and another one in the Arctic at ESRANGE at Kiruna (68 N; 22 E) which will operate to the final warming of spring 1988. The data are processed in real time at both stations. O3 and NO2 columns are transmitted together with surface and stratospheric temperature and winds. They are also recorded for further treatment and search for OClO and BrO. Only one month of data from Antarctica is available at the moment. Obtained during polar summer, they cannot show more than stable columns of O3 and NO2 and for the last species, the buildup of its diurnal variation.

  11. Acute bronchiolar injury following nitrogen dioxide exposure: a freeze fracture study

    SciTech Connect

    Case, B.W.; Gordon, R.E.; Kleinerman, J.

    1982-12-01

    Three groups of Syrian golden hamsters were exposed to NO/sub 2/ for 6, 24, or 48 hr to determine acute effects on intercellular junctional morphology in distal airways and alveolar epithelium. A fourth group, exposed for 48 hr, was allowed to recover for 2 days prior to sacrifice. Light and transmission electron microscopy of bronchiolar epithelium show ciliary loss and surface membrane damage, loss of ciliated cells, and epithelial flattening at 24 and 48 hr. Moderate to marked epithelial hyperplasia and nonciliated cell hypertrophy are noted after 48 hr. Some restoration of normal histoarchitecture is noted in bronchioles of animals allowed a 48-hr recovery period. Freeze fracture platinum-carbon replicas of bronchiolar epithelium show the gradual evolution of a severe disruption of tight junctional networks after 6, 24, and 48 hr of exposure. Following 2 days of ''recovery,'' bronchiolar tight junctions from animals exposed for 48 hr remain fragmented. The wide distribution of the junctionl material present suggests a regenerative process. Freeze fracture replicas of bronchial epithelium show similar fragmentation of tight junctions following 6-hr exposures. After longer intervals, however, there is a return to more normal appearances. Duration of NO/sub 2/ exposure has no systematic effect on the integrity of tight junctions in alveolar epithelium. The findings suggest that disruption of tight junctions may be an important specific determinant of increased bronchiolar epithelial permeability following brief exposures to nitrogen dioxide.

  12. Phase transition and chemical decomposition of liquid carbon dioxide and nitrogen mixture under extreme conditions

    NASA Astrophysics Data System (ADS)

    Xiao-Xu, Jiang; Guan-Yu, Chen; Yu-Tong, Li; Xin-Lu, Cheng; Cui-Ming, Tang

    2016-02-01

    Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen (CO2-N2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic (QMD) simulations based on density functional theory including dispersion corrections (DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm3 to 3.40 g/cm3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO2-N2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions (PCFs) and the distribution of various molecular components. The insulator-metal transition is demonstrated by means of the electronic density of states (DOS). Project supported by the National Natural Science Foundation of China (Grant Nos. 11374217, 11135012, and 11375262) and the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11176020).

  13. Thermo-chemical fuel removal from porous materials by oxygen and nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Möller, S.; Alegre, D.; Kreter, A.; Petersson, P.; Esser, H. G.; Samm, U.

    2014-04-01

    Thermo-chemical removal (TCR), or baking in reactive gases, is a candidate method to control the co-deposit related tritium inventory in fusion devices. TCR can be understood as reaction-diffusion processes in a porous material. O2-TCR was applied to 150-550 nm thick a-C:D layers with similar textures. A linear relation between the integral TCR rate and the layer thickness, as predicted by the understanding, was observed in the experiment, i.e. the time to remove the hydrogen inventory is independent of its initial amount. TCR with nitrogen dioxide (NO2) at temperatures of 200-350 °C was conducted with a set of a-C:D and W-C-H layers. At 350 °C NO2 removed ˜ 15% porosity a-C:D within 3 min. The O retention in remaining a-C:D was ≈ 1017 O cm-2. An activation energy of ≈ 0.78 eV for reactions of NO2 with D and C was determined. The results were applied for predictions of the TCR effectivity in ITER. The treatment of W-C-H led to O uptake (O/W ≈ 2-3), while W and C contents remained unchanged.

  14. Exposures to nitrogen dioxide in EXPOLIS-Helsinki: microenvironment, behavioral and sociodemographic factors.

    PubMed

    Rotko, T; Kousa, A; Alm, S; Jantunen, M

    2001-01-01

    Personal exposures to nitrogen dioxide (NO(2)) were monitored for 176 randomly selected inhabitants (25-55 years old) of Helsinki Metropolitan area as a part of the EXPOLIS (Air Pollution Exposure Distributions Within Adult Urban Populations in Europe) study between October 1996 and December 1997. NO(2) measurements were 48-h averages collected by Palmes passive sampler tubes. Differences in personal exposures to NO(2) were analyzed between sub-populations stratified by microenvironment, behavioral, socioeconomic and demographic factors. Factors significantly associated with differences in exposures to NO(2) were home and work location, housing characteristics, traffic volume near home, season and keeping windows open at home. Exposure to environmental tobacco smoke (ETS) and use of gas stove were also associated with increased personal exposures, although only few participants had a gas stove in Helsinki, and other gas appliances are non-existent. Single adults had higher average exposures to NO(2) than married or cohabiting participants, suggesting differences in living conditions between these two groups. Increased education was associated with decreased exposures to NO(2) and employed men were more exposed than unemployed men. Increased exposures to NO(2) were not associated with age or occupational status in Helsinki. Thus, behavioral and sociodemographic factors may have significant impact on personal exposures to NO(2) and should be considered in addition to environmental determinants in any monitoring program.

  15. Impact of residential nitrogen dioxide exposure on personal exposure: an international study.

    PubMed

    Levy, J I; Lee, K; Spengler, J D; Yanagisawa, Y

    1998-06-01

    Nitrogen dioxide (NO2) concentrations were measured during two-day winter periods in indoor and outdoor environments, and these concentrations were compared with simultaneously measured personal exposures in 18 cities in 15 countries around the world. Information was also gathered on activity patterns and household characteristics in order to determine the influences of these factors on personal exposures. All NO2 measurements were taken using passive filter badges. Personal exposures were found to vary greatly among the array of cities, with mean concentrations ranging between 11.0 ppb and 51.5 ppb. Personal NO2 exposures were more strongly correlated with indoor concentrations (r = 0.75) than with outdoor concentrations (r = 0.57) when all countries were considered simultaneously. Use of a gas stove in the home was the dominant activity influencing NO2 concentrations, with a 67% increase in mean personal NO2 exposure and an increase in indoor-outdoor ratios from 0.7 to 1.2 for participants using gas stoves, although preliminary evidence indicates the importance of combustion space heaters as well. These associations indicate the global nature of the correlation between personal NO2 exposures and indoor NO2 sources such as gas stoves or space heaters, demonstrating that this relationship is not dependent on country-specific parameters.

  16. Nitrogen Dioxide pollution and hazardous household environment: what impacts more congenital malformations.

    PubMed

    Landau, D; Novack, L; Yitshak-Sade, M; Sarov, B; Kloog, I; Hershkovitz, R; Grotto, I; Karakis, I

    2015-11-01

    Nitrogen Dioxide (NO2) is a product of fuel combustion originating mainly from industry and transportation. Studies suggest an association between NO2 and congenital malformations (CM). We investigated an independent effect of NO2 on CM by adjusting to individual factors and household environment in 1024 Bedouin-Arab pregnant women in southern Israel. This population is characterised by high rates of CMs, frequent consanguineous marriages, paternal smoking, temporary housing and usage of open fire for heat cooking. Information on household risk factors was collected during an interview. Ambient measurements of 24-h average NO2 and meteorological conditions were obtained from 13 local monitors. Median value of daily NO2 measured in the area was 6.78ppb. CM was diagnosed in 8.0% (82) of offspring. Maternal NO2 exposure during the 1st trimester >8.6ppb was significantly associated with minor CM (RR=2.68, p=0.029). Major CM were independently associated with maternal juvenile diabetes (RR=9.97, p-value=0.002) and heating by open fire (RR=2.00, p-value=0.049), but not NO2 exposure. We found that NO2 emissions had an independent impact only on minor malformations, whereas major malformations depended mostly on the household environment. Antepartum deaths were associated by maternal morbidity.

  17. Aspects of nitrogen dioxide toxicity in environmental urban concentrations in human nasal epithelium

    SciTech Connect

    Koehler, C.; Ginzkey, C.; Friehs, G.; Hackenberg, S.; Froelich, K.; Scherzed, A.; Burghartz, M.; Kessler, M.; Kleinsasser, N.

    2010-06-01

    Cytotoxicity and genotoxicity of nitrogen dioxide (NO{sub 2}) as part of urban exhaust pollution are widely discussed as potential hazards to human health. This study focuses on toxic effects of NO{sub 2} in realistic environmental concentrations with respect to the current limit values in a human target tissue of volatile xenobiotics, the epithelium of the upper aerodigestive tract. Nasal epithelial cells of 10 patients were cultured as an air-liquid interface and exposed to 0.01 ppm NO{sub 2}, 0.1 ppm NO{sub 2}, 1 ppm NO{sub 2}, 10 ppm NO{sub 2} and synthetic air for half an hour. After exposure, genotoxicity was evaluated by the alkaline single-cell microgel electophoresis (Comet) assay and by induction of micronuclei in the micronucleus test. Depression of proliferation and cytotoxic effects were determined using the micronucleus assay and trypan blue exclusion assay, respectively. The experiments revealed genotoxic effects by DNA fragmentation starting at 0.01 ppm NO{sub 2} in the Comet assay, but no micronucleus inductions, no changes in proliferation, no signs of necrosis or apoptosis in the micronucleus assay, nor did the trypan blue exclusion assay show any changes in viability. The present data reveal a possible genotoxicity of NO{sub 2} in urban concentrations in a screening test. However, permanent DNA damage as indicated by the induction of micronuclei was not observed. Further research should elucidate the effects of prolonged exposure.

  18. Mineral elements of subtropical tree seedlings in response to elevated carbon dioxide and nitrogen addition.

    PubMed

    Huang, Wenjuan; Zhou, Guoyi; Liu, Juxiu; Zhang, Deqiang; Liu, Shizhong; Chu, Guowei; Fang, Xiong

    2015-01-01

    Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO2) concentrations and nitrogen (N) deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), copper (Cu) and manganese (Mn) in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO2 (ca. 700 μmol CO2 mol(-1)) and N addition (100 kg N ha(-1) yr(-1)) from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO2 and N addition than those in the leaves. Elevated CO2 did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO2 and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO2 and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics. PMID:25794046

  19. Visible-Light-Induced Bactericidal Activity of Titanium Dioxide Co-doped with Nitrogen and Silver

    PubMed Central

    Wu, Pinggui; Xie, Rongcai; Imlay, Kari; Shang, Jian-Ku

    2011-01-01

    Titanium dioxide nanoparticles co-doped with nitrogen and silver (Ag2O/TiON) were synthesized by the sol-gel process and found to be an effective visible light driven photocatalyst. The catalyst showed strong bactericidal activity against Escherichia coli (E. coli) under visible light irradiation (λ> 400 nm). In x-ray photoelectron spectroscopy and x-ray diffraction characterization of the samples, the as-added Ag species mainly exist as Ag2O. Spin trapping EPR study showed Ag addition greatly enhanced the production of hydroxyl radicals (•OH) under visible light irradiation. The results indicate that the Ag2O species trapped eCB− in the process of Ag2O/TiON photocatalytic reaction, thus inhibiting the recombination of eCB− and hVB+ in agreement with the stronger photocatalytic bactericidal activity of Ag2O/TiON. The killing mechanism of Ag2O/TiON under visible light irradiation is shown to be related to oxidative damages in the forms of cell wall thinning and cell disconfiguration. PMID:20726520

  20. Improving spatial nitrogen dioxide prediction using diffusion tubes: A case study in West Central Scotland

    NASA Astrophysics Data System (ADS)

    Pannullo, Francesca; Lee, Duncan; Waclawski, Eugene; Leyland, Alastair H.

    2015-10-01

    It has been well documented that air pollution adversely affects health, and epidemiological pollution-health studies utilise pollution data from automatic monitors. However, these automatic monitors are small in number and hence spatially sparse, which does not allow an accurate representation of the spatial variation in pollution concentrations required for these epidemiological health studies. Nitrogen dioxide (NO2) diffusion tubes are also used to measure concentrations, and due to their lower cost compared to automatic monitors are much more prevalent. However, even combining both data sets still does not provide sufficient spatial coverage of NO2 for epidemiological studies, and modelled concentrations on a regular grid from atmospheric dispersion models are also available. This paper proposes the first modelling approach to using all three sources of NO2 data to make fine scale spatial predictions for use in epidemiological health studies. We propose a geostatistical fusion model that regresses combined NO2 concentrations from both automatic monitors and diffusion tubes against modelled NO2 concentrations from an atmospheric dispersion model in order to predict fine scale NO2 concentrations across our West Central Scotland study region. Our model exhibits a 47% improvement in fine scale spatial prediction of NO2 compared to using the automatic monitors alone, and we use it to predict NO2 concentrations across West Central Scotland in 2006.

  1. Further studies on the effect of nitrogen dioxide on mast cells: The effect of the metabolite, nitrite

    SciTech Connect

    Fujimaki, Hidekazu ); Ozawa, Masashi ); Bissonnette, E.; Befus, A.D. )

    1993-05-01

    To evaluate the relationship between atmospheric nitrogen dioxide exposure and the development of allergic diseases, the effects of nitrite as a chemical product of inhaled nitrogen dioxide on mast cell functions were investigated. We have studied nitride-induced histamine release from two functionally distinct mast cell populations, namely peritoneal mast cells (PMC) and intestinal mucosal mast cells (IMMC) of Nippostrongylus brasiliensis-infected rats. High concentrations of nitrite alone (10, 20, and 50 mM) induced histamine release from IMMC, but not from PMC. Moreover, histamine release from PMC and IMMC stimulated with sensitizing antigen was significantly enhanced by pretreatment with 50 mM nitrite or nitrate. No differences in histamine release from nitrite-treated and control PMC were seen below 1 mM. To investigate the effect of nitrite on tumor cell cytotoxic activity, PMC were incubated with various concentrations of nitrite. Pretreatment with 5 and 50 mM nitrite markedly depressed tumor necrosis factor (TNF)-[alpha]-dependent natural cytotoxicity of PMC for the tumor target WEHI-164. Thus, high concentrations of nitrite enhanced mast cell histamine release, but depressed TNF-[alpha]-dependent cytotoxicity. However, low concentrations of nitrite (<1 mM) that would normally be produced by short-term atmospheric exposure to nitrogen dioxide may have no significant effects on mast cell functions. 27 refs., 3 figs., 1 tab.

  2. Effect of carbon dioxide and nitrogen on the diffusivity of methane confined in nano-porous carbon aerogel

    SciTech Connect

    Mavila Chathoth, Suresh; He, Lilin; Mamontov, Eugene; Melnichenko, Yuri B

    2012-01-01

    The microscopic diffusivity of methane (CH{sub 4}) confined in nano-porous carbon aerogel was investigated as a function of added carbon dioxide (CO{sub 2}) and nitrogen (N{sub 2}) pressure using quasi-elastic neutron scattering (QENS). In the range of the external pressure of 1-2.5 MPa, the self-diffusivity of methane was found to increase with CO{sub 2} pressure and remain practically unchanged in the N{sub 2} environment. Increasing mobility of methane with CO{sub 2} pressure suggests that the adsorbed CH4 molecules become gradually replaced by CO{sub 2} on the surface of carbon aerogel pores, whereas the presence of N{sub 2} does not induce the replacement. The molecular mobility of the methane, with or without added carbon dioxide and nitrogen, is described by the unrestricted diffusion model, which is characteristic of methane compressed in small pores. On the other hand, both nitrogen and carbon dioxide molecules in carbon aerogel, when studied alone, with no methane present, follow a jump diffusion process, characteristic of the molecular mobility in the densified adsorbed layers on the surface of the aerogel pores.

  3. Importance of network density of nanotube: Effect on nitrogen dioxide gas sensing by solid state resistive sensor

    NASA Astrophysics Data System (ADS)

    Mishra, Prabhash; Grachyova, D. V.; Moskalenko, A. S.; Shcherbak, M. A.; Pavelyev, V. S.

    2016-04-01

    Dispersion of single-walled carbon nanotubes (SWCNTs) is an established fact, however, its effect on toxic gas sensing for the development of solid state resistive sensor was not well reported. In this report, the dispersion quality of SWCNTs has been investigated and improved, and this well-dispersed SWCNTs network was used for sensor fabrication to monitor nitrogen dioxide gas. Ultraviolet (UV)-visible spectroscopic studies shows the strength of SWNTs dispersion and scanning electron microscopy (SEM) imaging provides the morphological properties of the sensor device. In this gas sensor device, two sets of resistive type sensors were fabricated that consisting of a pair of interdigitated electrodes (IDEs) using dielectrophoresis technique with different SWCNTs network density. With low-density SWCNTs networks, this fabricated sensor exhibits a high response for nitrogen dioxide sensing. The sensing of nitrogen dioxide is mainly due to charge transfer from absorbed molecules to sidewalls of nanotube and tube-tube screening acting a major role for the transport properties of charge carriers.

  4. Heterogeneous Atmospheric Chemistry of Lead Oxide Particles with Nitrogen Dioxide Increases Lead Solubility: Environmental and Health Implications

    PubMed Central

    Baltrusaitis, Jonas; Chen, Haihan; Rubasinghege, Gayan

    2012-01-01

    Heterogeneous chemistry of nitrogen dioxide with lead-containing particles is investigated to better understand lead metal mobilization in the environment. In particular, PbO particles, a model lead-containing compound due to its wide spread presence as a component of lead paint and as naturally occurring minerals, massicot and litharge, are exposed to nitrogen dioxide at different relative humidity. X-ray photoelectron spectroscopy (XPS) shows that upon exposure to nitrogen dioxide the surface of PbO particles react to form adsorbed nitrates and lead nitrate thin films with the extent of formation of nitrate relative humidity dependent. Surface adsorbed nitrate increases the amount of dissolved lead. These reacted particles are found to have an increase in the amount of lead that dissolves in aqueous suspensions at circumneutral pH compared to unreacted particles. These results point to the potential importance and impact that heterogeneous chemistry with trace atmospheric gases can have on increasing solubility and therefore the mobilization of heavy metals, such as lead, in the environment. This study also show that surface intermediates, such as adsorbed nitrates, that form can yield higher concentrations of lead in water systems. In the environment, these water systems can include drinking water, ground water, estuaries and lakes. PMID:23057678

  5. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    SciTech Connect

    O'Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

    2000-07-01

    The Albany Research Center (ARC) of the US Department of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO{sub 2} pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185 C and a partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine

  6. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction

  7. The Determination of Total Nitrogen Oxides in Stack Gases. Phenoldisulfonic Acid Method.

    ERIC Educational Resources Information Center

    Thorpe, Charles J. D.

    The well known Saltzman method for oxides of nitrogen is intended for the determination of these constituents in the ambient atmosphere in the range of a few parts per billion to about 5ppm. However, when sulfur dioxide is present in the gas to be sampled and/or the concentration range of the oxides of nitrogen is from five to several thousand…

  8. Investigation of the Nitrogen Dioxide Pollution in Urban Areas using a New Portable ICAD Instrument

    NASA Astrophysics Data System (ADS)

    Horbanski, Martin; Pöhler, Denis; Adler, Tim; Lampel, Johannes; Kanatschnig, Florian; Oesterle, Tobias; Reh, Miriam; Platt, Ulrich

    2016-04-01

    Nitrogen oxides (NOx) and especially nitrogen dioxide (NO2), are still among of the most problematic pollutants in urban areas not only in developing, but also in industrialized countries. Despite the measures taken to reduce their emissions, NO2 concentrations in many urban areas exceed the WHO recommended limits of 40 μg/m3 for annual mean and 200 μg/m3 for 1 hour mean. Additionally it is known that the NO2 concentration in urban areas has a strong spatial and temporal variability, due to the large number of NOx emitting point sources (mainly traffic) found in densely populated areas. However, the layout of air monitoring networks in most urban areas, installed to continuously monitor the officially prescribed NO2 limits, does not reflect the high spatial variability because they only conduct measurements at a single or few selected sampling points, mainly on major roads, which are often not representative for the whole urban area. At present these uncertainties about the spatial NO2 distribution constitute severe limitations for the assessment of health risks, for the quality of chemical model calculations, and for developing effective measures to reduce NOx emissions. We developed a new light-weight and portable ICAD (Iterative Cavity Enhanced DOAS) instrument which detects NO2 at a detection limit as low as 0.2 μg/m3 with a high time resolution of seconds. The instrument is based on the Cavity Enhanced (CE-) DOAS technique, which directly identifies and quantifies NO2 by its differential optical absorption. Therefore, it does not suffer from interferences by other trace gas species like O3 or NOy. This is a great advantage over other NO2 instruments (e.g. solid state detectors or chemiluminescence instruments). We present the result of ICAD NO2 measurements, which we recently performed in more than 10 German cities. The ICAD instrument was mounted on mobile platforms like cars and bicycles, measuring the NO2 concentrations along carefully selected tracks

  9. Performance of Multi-City Land Use Regression Models for Nitrogen Dioxide and Fine Particles

    PubMed Central

    Beelen, Rob; Bellander, Tom; Birk, Matthias; Cesaroni, Giulia; Cirach, Marta; Cyrys, Josef; de Hoogh, Kees; Declercq, Christophe; Dimakopoulou, Konstantina; Eeftens, Marloes; Eriksen, Kirsten T.; Forastiere, Francesco; Galassi, Claudia; Grivas, Georgios; Heinrich, Joachim; Hoffmann, Barbara; Ineichen, Alex; Korek, Michal; Lanki, Timo; Lindley, Sarah; Modig, Lars; Mölter, Anna; Nafstad, Per; Nieuwenhuijsen, Mark J.; Nystad, Wenche; Olsson, David; Raaschou-Nielsen, Ole; Ragettli, Martina; Ranzi, Andrea; Stempfelet, Morgane; Sugiri, Dorothea; Tsai, Ming-Yi; Udvardy, Orsolya; Varró, Mihaly J.; Vienneau, Danielle; Weinmayr, Gudrun; Wolf, Kathrin; Yli-Tuomi, Tarja; Hoek, Gerard; Brunekreef, Bert

    2014-01-01

    Background: Land use regression (LUR) models have been developed mostly to explain intraurban variations in air pollution based on often small local monitoring campaigns. Transferability of LUR models from city to city has been investigated, but little is known about the performance of models based on large numbers of monitoring sites covering a large area. Objectives: We aimed to develop European and regional LUR models and to examine their transferability to areas not used for model development. Methods: We evaluated LUR models for nitrogen dioxide (NO2) and particulate matter (PM; PM2.5, PM2.5 absorbance) by combining standardized measurement data from 17 (PM) and 23 (NO2) ESCAPE (European Study of Cohorts for Air Pollution Effects) study areas across 14 European countries for PM and NO2. Models were evaluated with cross-validation (CV) and hold-out validation (HV). We investigated the transferability of the models by successively excluding each study area from model building. Results: The European model explained 56% of the concentration variability across all sites for NO2, 86% for PM2.5, and 70% for PM2.5 absorbance. The HV R2s were only slightly lower than the model R2 (NO2, 54%; PM2.5, 80%; PM2.5 absorbance, 70%). The European NO2, PM2.5, and PM2.5 absorbance models explained a median of 59%, 48%, and 70% of within-area variability in individual areas. The transferred models predicted a modest-to-large fraction of variability in areas that were excluded from model building (median R2: NO2, 59%; PM2.5, 42%; PM2.5 absorbance, 67%). Conclusions: Using a large data set from 23 European study areas, we were able to develop LUR models for NO2 and PM metrics that predicted measurements made at independent sites and areas reasonably well. This finding is useful for assessing exposure in health studies conducted in areas where no measurements were conducted. Citation: Wang M, Beelen R, Bellander T, Birk M, Cesaroni G, Cirach M, Cyrys J, de Hoogh K, Declercq C

  10. The effect of nitrogen dioxide on particle formation during ozonolysis of two abundant monoterpenes indoors

    NASA Astrophysics Data System (ADS)

    Nøjgaard, Jacob Klenø; Bilde, Merete; Stenby, Charlotte; Nielsen, Ole John; Wolkoff, Peder

    The effect of the nitrogen dioxide (NO 2) concentration on particle formation during ozonolysis of two abundant monoterpenes indoors, α-pinene and d-limonene, was studied in dry air in 1000 l Tedlar bags at 21±2 °C and ambient pressure. Particle size distributions were measured during 1 h after the reaction was initiated. In mixtures of 50 parts per billion volume (ppbv) of monoterpene and 50 ppbv of ozone (O 3), d-limonene produced about five times as many particles (10-350 nm) as α-pinene after 60 min. The presence of NO 2 introduced an additional loss term for O 3, resulting in formation of the nitrate radical. This affected particle formation, since the nucleation potential of NO 3 is much lower than O 3. Modeling showed that the observed decrease in particle concentration from d-limonene/O 3/NO 2 mixtures was likely to be ascribed to the O 3/NO 2 reaction at NO 2 concentrations <150 ppb, above which unknown mechanisms additionally reduced the particle formation. In similar experiments with α-pinene, the particle concentration and volume were substantially reduced in the presence of NO 2, e.g. 162 ppbv NO 2 reduced the particle number concentration by a factor of 10. In addition, the detection of particle formation was delayed as the NO 2 concentration increased, but the additional loss of O 3 in the O 3/NO 2 reaction could not explain the observation. The particle mode progressively increased with the NO 2 concentration for both monoterpenes. Oxidation of d-limonene may be highly relevant for new particle formation in indoor air, whereas ozonolysis products of α-pinene seem less likely to nucleate in indoor environments.

  11. Ship-based MAX-DOAS measurements of nitrogen dioxide in the South China Sea

    NASA Astrophysics Data System (ADS)

    Schreier, Stefan F.; Peters, Enno; Richter, Andreas; Wittrock, Folkard; Burrows, John P.

    2014-05-01

    In November 2011, the SHIVA-Sonne campaign took place in the South China Sea in order to investigate the transport of very short-lived substances to the stratosphere for a better understanding of their role in ozone depletion. Among other instruments, a Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was placed on board the RV Sonne to measure scattered sunlight at different elevation angles. These measurements can be used for the retrieval of vertical columns of several trace gases (e.g. nitrogen dioxide (NO2), formaldehyde (HCHO), and iodine monoxide (IO)) by applying the DOAS method. In this study, we present tropospheric NO2 vertical columns (TVC NO2) retrieved from the MAX-DOAS measurements between 17 and 28 November 2011. During this period, the tropospheric NO2 levels were rather low (< 1 x 1015 molec cm-2) in the open sea most of the time. However, elevated NO2 levels (> 5 x 1015 molec cm-2) were observed when other large vessels navigated in the proximity of RV Sonne. Moreover, elevated levels of TVC NO2 (> 3 x 1015 molec cm-2) were also observed close to the coast of the island Borneo. The web-based version of the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was used for the calculation of 24 h backward trajectories to better identify the sources of these elevated levels of TVC NO2. The analysis of the backward trajectories indicated that some cases with elevated tropospheric NO2 levels could be the result of NO2 transport from biomass burning and urban/industrial sources. In summary, the highest levels of TVC NO2 were found to be the result of the combustion process of large vessel engines. The contribution of biomass burning and urban/industrial sources to the tropospheric NO2 level in the South China Sea is rather low, at least during this part of the season.

  12. Biochemical studies on strain differences of mice in the susceptibility to nitrogen dioxide

    SciTech Connect

    Ichinose, T.; Suzuki, A.K.; Tsubone, H.; Sagai, M.

    1982-11-01

    Strain differences of mice in their susceptibility to nitrogen dioxide (NO/sub 2/) were examined by measuring the activities of antioxidative protective enzymes, and the amounts of antioxidants and lipid peroxides in lungs. Four strains of mice: ICR, BALB/c, ddy and C57BL/6 were used in this study and their LC/sub 50/ values after exposure to NO/sub 2/ for 16 hr were: 38, 49, 51 and 64 ppm, respectively. Genetic strain differences were observed in the enzyme activities, the antioxidant contents and lipid peroxide contents among these four different strains. The activities of glutathione peroxidase (GP/sub x/), glutathione S-transferase, and superoxide dismutase (SOD), and the contents of non-protein sulfyhdryls (NPSH), ..cap alpha..-tocopherol (..cap alpha..-Toc) and total lipids in lungs of the four strains were related to their LC/sub 50/, while TBA reactants in lungs of the four strains were inversely related to their LC/sub 50/. After exposure to 20 ppm NO/sub 2/ for 16 hr, the activities of the protective enzymes and the contents of NPSH decreased, while the level of ..cap alpha..-Toc increased markedly. The activities of GP/sub x/, 6-phosphogluconate dehydrogenase, SOD and disulfide reductase, and the contents of NPSH, ..cap alpha..-Toc and total lipids were also related to their LC/sub 50/. On the other hand, TBA reactants increased higher than those of the control groups and were inversely related to their LC/sub 50/. These results suggest that the protective enzymes and the antioxidants are important factors as defence mechanism in lungs to NO/sub 2/ and that the intensity of the protective systems in pigmented strains is generally greater than that in albino strains.

  13. Combined nitrogen oxides/sulfur dioxide control in dry scrubber systems

    SciTech Connect

    Harkness, J. B.L.; Gorski, A. J.; Huang, H. S.

    1989-02-01

    Argonne National Laboratory (ANL) is investigating alternative control concepts that involve modifying existing SO{sub 2}-removal processes and sorbents, with the objective of achieving simultaneous removal of nitrogen oxides (NO{sub x}) and sulfur dioxide (SO{sub 2}). Laboratory-scale research conducted using a fixed-bed reactor and a spray-dryer/fabric-filter system has been paralleled by field tests at ANL's commercial-scale (20-MW electric equivalent) dry scrubber. In the fixed-bed experiments, a range of chemical reagents was surveyed, and the best-performing additives were studied in detail. Sodium chloride, sodium bisulfite, sodium hydroxide, and Fe(II)*EDTA were found to increase both NO{sub x} and SO{sub 2} removals; the additives did not appear to increase NO{sub x} removal directly, but they interacted strongly with the other primary variables to improve sorbent performance. The laboratory spray-dryer system was used to study the effects on combined NO{sub x}/SO{sub 2} removal of the best-performing fixed-bed additives and certain process modifications. The tests showed that sodium chloride increased NO{sub x} removal at all temperatures; sodium bisulfite was generally less effective, and calcium chloride was effective only at 65{degree}C. Up to 80{degree}C, all three additives significantly improved SO{sub 2} removal, but improvement ceased at higher temperatures. This report discusses the experimental results in terms of the effects the additives and principal process variables had on NO{sub x} and SO{sub 2} removals and the mechanistic implications. 14 refs., 74 figs., 33 tabs.

  14. Effects of nitrogen dioxide exposure on pulmonary function and airway reactivity in normal humans.

    PubMed

    Frampton, M W; Morrow, P E; Cox, C; Gibb, F R; Speers, D M; Utell, M J

    1991-03-01

    Nitrogen dioxide (NO2) is a product of combustion that has become recognized as a significant component of indoor air in some homes. Despite extensive study, it remains unresolved whether exposures to low levels of NO2 affect airway function or reactivity. These studies were designed to assess effects of various levels and patterns of NO2 exposure on pulmonary function and airway reactivity in normal humans. Normal volunteers screened for the absence of airway hyperreactivity were exposed for 3 h in an environmental chamber to purified air or NO2, separated by at least 2 wk, according to three protocols: (1) continuous 0.60 ppm NO2, (2) baseline 0.05 ppm NO2 with intermittent peaks of 2.0 ppm, and (3) continuous 1.5 ppm NO2. Subjects exercised for 10 min of each 30 min at a level sufficient to result in a minute ventilation near 40 L/min. Pulmonary function was measured before, during, and after exposure. Airway reactivity to increasing doses of carbachol was assessed 30 min after exposure. NO2 did not directly alter pulmonary function in any of the exposure protocols. In addition, airway reactivity was not altered by continuous exposure to 0.60 ppm or intermittent peaks of 2.0 ppm NO2. In contrast, continuous exposure to 1.5 ppm NO2 resulted in a greater fall in FVC and FEV1 in response to carbachol than after exposure to air (percent decrease in FVC: 1.5% after air, 3.9% after NO2, p less than 0.01). We conclude that for subjects without airway hyperreactivity, exposure to 1.5 ppm NO2 for 3 h increases airway reactivity, whereas repeated 15-min exposures to 2.0 ppm NO2 do not alter airway reactivity. PMID:2001061

  15. Pulmonary effects of ozone and nitrogen dioxide alone and combined in healthy and asthmatic adolescent subjects

    SciTech Connect

    Koenig, J.Q.; Covert, D.S.; Smith, M.S.; van Belle, G.; Pierson, W.E.

    1988-12-01

    Separate exposures to 0.12 ppm ozone (O3) or 0.18 ppm nitrogen dioxide (NO2) have not demonstrated consistent changes in pulmonary function in adolescent subjects. However, in polluted urban air, O3 and NO2 occur in combination. Therefore, this project was designed to investigate the pulmonary effects of combined O3 and NO2 exposures during intermittent exercise in adolescent subjects. Twelve healthy and twelve well-characterized asthmatic adolescent subjects were exposed randomly to clean air or 0.12 ppm O3 and 0.30 ppm NO2 alone or in combination during 60 minutes of intermittent moderate exercise (32.5 1/min). The inhalation exposures were carried out while the subjects breathed on a rubber mouthpiece with nose clips in place. The following pulmonary functional values were measured before and after exposure: peak flow, total respiratory resistance, maximal flow at 50 and 75 percent of expired vital capacity, forced expiratory volume in one second and forced vital capacity (FVC). Statistical significance of pulmonary function changes was tested by analysis of covariance for repeated measures. After exposure to 0.12 ppm O3 a significant decrease was seen in maximal flow at 50% of FVC in asthmatic subjects. After exposure to 0.30 ppm NO2 a significant decrease was seen in FVC also in the asthmatic subjects. One possible explanation for these changes is the multiple comparison effect. No significant changes in any parameters were seen in the asthmatic subjects after the combined O3-NO2 exposure or in the healthy subjects after any of the exposures.

  16. Cavity Attenuation Phase Shift Detection of Trace Atmospheric Species: Nitrogen Dioxide

    NASA Astrophysics Data System (ADS)

    Freedman, A.; Herndon, S. C.; Kebabian, P. L.; Wood, E. C.

    2007-12-01

    We present details of an apparatus capable of measuring optical extinction (i.e., scattering and/or absorption) which employs one variant of cavity enhanced detection, specifically cavity attenuated phase shift spectroscopy (CAPS). It uses a near confocal arrangement of two high reflectivity (R~0.9999) mirrors in tandem with an enclosed cell 26 cm in length, a light emitting diode (LED) and a vacuum photodiode detector. Square wave modulated light from the LED passes through the sample cell and is detected as a distorted waveform which is characterized by a phase shift with respect to the initial modulation. The amount of that phase shift is a function of fixed instrument properties - cell length, mirror reflectivity, and modulation frequency - and of the presence of a scatterer or absorber (air, particles, trace gases, etc.) within the cell. The monitor is enclosed within a standard rack-mounted instrumentation box, weighs 10 kg and uses 70 W of electrical power including a vacuum pump. The instrument has demonstrated a detection limit of 0.02 Mm-1 (1σ) in ten seconds integration time and a baseline drift of less than ± 0.1 Mm-1 over a 24 hour period. We also present an intercomparison of measurements of ambient nitrogen dioxide concentrations using this sensor, a quantum cascade laser-based infrared absorption spectrometer and a standard hot metal/chemiluminescence-based NOx analyzer. Measurements using the quantum cascade-laser and CAPS monitor agree well within the inter- calibration error. The chemiluminescence analyzer data falls outside the expected error band, a fact that is ascribed to the presence of known chemical interferences for the chemiluminescence-based analyzer.

  17. Subacute effects of nitrogen dioxide on membrane constituents of lung, liver, and kidney of rats

    SciTech Connect

    Takahashi, Y.; Mochitate, K.; Miura, T.

    1986-10-01

    Male Wistar rats were exposed to 0.4, 1.2, and 4.0 ppm nitrogen dioxide (NO/sub 2/) for up to 14 weeks to examine subacute effects of NO/sub 2/ on membrane constituents of lung, liver, and kidney. In the lung, cytochrome P-450 decreased to 59% and 57% of the control values after 1 and 10 weeks of exposure to 4.0 ppm NO/sub 2/, respectively, and remained at control levels at other exposure periods. The activity of succinate-cytochrome c reductase also decreased to 75% of the control values after 2, 4, and 14 weeks of exposure to 4.0 ppm NO/sub 2/, respectively. Exposures to 0.4 and 1.2 ppm NO/sub 2/ resulted in similar patterns of alterations in these enzymes. In the liver, cytochrome P-450 decreased to 72%, 70%, and 73% of the control values after 1, 5, and 8 weeks of exposure to 4.0 ppm NO/sub 2/, respectively and remained at control levels at other exposure periods. The activity of NADPH-cytochrome P-450 reductase also decreased in a fashion similar to cytochrome P-450. Exposures to 0.4 and 1.2 ppm NO/sub 2/ resulted in similar patterns of alterations in these enzymes. In addition, cytochrome b/sub 5/ showed a reduced value between 5 and 12 weeks of exposures to 1.2 and 4.0 ppm NO/sub 2/ and then recovered. In the kidney, all components of the microsomal electron-transport systems increased during 12-week exposures to 1.2 and 4.0 ppm NO/sub 2/.

  18. Fine particulate air pollution, nitrogen dioxide, and systemic autoimmune rheumatic disease in Calgary, Alberta

    PubMed Central

    Bernatsky, Sasha; Smargiassi, Audrey; Johnson, Markey; Kaplan, Gilaad G.; Barnabe, Cheryl; Svenson, Larry; Brand, Allan; Bertazzon, Stefania; Hudson, Marie; Clarke, Ann E; Fortin, Paul; Edworthy, Steven; Bélisle, Patrick; Joseph, Lawrence

    2015-01-01

    Objective To estimate the association between fine particulate (PM2.5) and nitrogen dioxide (NO2) pollution and systemic autoimmune rheumatic diseases (SARDs). Methods Associations between ambient air pollution (PM2.5 and NO2) and SARDs were assessed using land-use regression models for Calgary, Alberta and administrative health data (1993-2007). SARD case definitions were based on ≥2 physician claims, or ≥1 rheumatology billing code; or ≥1 hospitalization code (for systemic lupus, Sjogren's Syndrome, scleroderma, polymyositis, dermatomyositis, or undifferentiated connective tissue disease). Bayesian hierarchical latent class regression models estimated the probability that each resident was a SARD case, based on these case definitions. The sum of individual level probabilities provided the estimated number of cases in each area. The latent class model included terms for age, sex, and an interaction term between age and sex. Bayesian logistic regression models were used to generate adjusted odds ratios (OR) for NO2 and PM2.5. pollutant models, adjusting for neighborhood income, age, sex, and an interaction between age and sex. We also examined models stratified for First-Nations (FN) and non-FN subgroups. Results Residents that were female and/or aged > 45 had a greater probability of being a SARD case, with the highest OR estimates for older females. Independently, the odds of being a SARDs case increased with PM2.5 levels, but the results were inconclusive for NO2. The results stratified by FN and Non-FN groups were not distinctly different. Conclusion In this urban Canadian sample, adjusting for demographics, exposure to PM2.5 was associated with an increased risk of SARDs. The results for NO2 were inconclusive. PMID:25988990

  19. On the Ratio of Sulfur Dioxide to Nitrogen Oxides as an Indicator of Air Pollution Sources.

    NASA Astrophysics Data System (ADS)

    Nirel, Ronit; Dayan, Uri

    2001-07-01

    The ratio of sulfur dioxide to nitrogen oxides (RSN = SO2/NOx) is one indicator of air pollution sources. The role of this ratio in source attribution is illustrated here for the Ashdod area, located in the southern coastal plain of Israel. The main sources of pollution in the area are the tall stacks of the Eshkol power plant, the stacks of oil refineries, and areal sources (stationary and mobile). The factors that affect RSN are studied using four regression models: a binary regression tree in original scale, a tree in logarithmic scale, a data partition produced by a combination of the two trees, and a linear regression model. All models have similar relative prediction error, with the combined partition best highlighting the sources of variability in RSN: (a) very low values (interquartile range of [0.12, 0.48]) are associated with traffic, (b) low values ([0.43, 1.00]) are attributed to the power plant and to daytime emissions of local industry, (c) medium values ([0.74, 1.90]) are associated with local industry emissions during cooler hours of the day and refinery emissions mainly on slow wind episodes, and (d) high values ([1.07, 4.30]) are attributed to refinery emissions during moderate to fast wind episodes. Analysis of the number of episodes of increased concentrations indicates that, during 1996 and 1997, about 42% of SO2 episodes are attributable to the power plant and 33% to the refineries. Increased-NOx episodes are mainly contributed by traffic (91%) and power plant (4.5%) emissions.

  20. Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide

    NASA Astrophysics Data System (ADS)

    Schneider, P.; Lahoz, W. A.; van der A, R.

    2015-02-01

    Trends in tropospheric nitrogen dioxide (NO2) columns over 66 large urban agglomerations worldwide have been computed using data from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the Envisat platform for the period August 2002 to March 2012. A seasonal model including a~linear trend was fitted to the satellite-based time series over each site. The results indicate distinct spatial patterns in trends. While agglomerations in Europe, North America, and some locations in East Asia/Oceania show decreasing tropospheric NO2 levels on the order of -5% yr-1, rapidly increasing levels of tropospheric NO2 are found for agglomerations in large parts of Asia, Africa, and South America. The site with the most rapidly increasing absolute levels of tropospheric NO2 was found to be Tianjin in China with a trend of 3.04 (±0.47) × 1015 molecules cm-2yr-1, whereas the site with the most rapidly increasing relative trend was Kabul in Afghanistan with 14.3 (±2.2) % yr-1. In total, 34 sites exhibited increasing trends of tropospheric NO2 throughout the study period, 24 of which were found to be statistically significant. A total of 32 sites showed decreasing levels of tropospheric NO2 during the study period, of which 20 sites did so at statistically significant magnitudes. Overall, going beyond the relatively small set of megacities investigated previously, this study provides the first consistent analysis of recent changes in tropospheric NO2 levels over most large urban agglomerations worldwide, and indicates that changes in urban NO2 levels are subject to substantial regional differences as well as influenced by economic and demographic factors.

  1. Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide

    NASA Astrophysics Data System (ADS)

    Schneider, P.; Lahoz, W. A.; van der A, R.

    2014-09-01

    Trends in tropospheric nitrogen dioxide (NO2) concentrations over 66 large urban agglomerations worldwide have been computed using data from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the Envisat platform for the period August 2002 to March 2012. A seasonal model including a linear trend was fitted to the satellite-based time series over each site. The results indicate distinct spatial patterns in trends. While agglomerations in Europe, North America, and some locations in East Asia/Oceania show decreasing tropospheric NO2 levels on the order of -5 % yr-1, rapidly increasing levels of tropospheric NO2 are found for agglomerations in large parts of Asia, Africa, and South America. The site with the most rapidly increasing absolute levels of tropospheric NO2 was found to be Tianjin in China with a trend value of 3.04 (±0.47) × 1015 molecules cm-2 yr-1, whereas the site with the most rapidly increasing relative trend was Kabul in Afghanistan with 14.3 (±2.2) % yr-1. In total, 34 sites exhibited increasing trends of tropospheric NO2 throughout the study period, 24 of which were found to be statistically significant. A total of 32 sites showed decreasing levels of tropospheric NO2 during the study period, of which 20 sites did so at statistically significant magnitudes. Overall, going beyond the relatively small set of megacities investigated previously, this study provides the first consistent analysis of recent changes in tropospheric NO2 levels over most large urban agglomerations worldwide.

  2. Signature of tropospheric ozone and nitrogen dioxide from space: A case study for Athens, Greece

    NASA Astrophysics Data System (ADS)

    Varotsos, C.; Christodoulakis, J.; Tzanis, C.; Cracknell, A. P.

    2014-06-01

    The aim of the present study is to investigate the variability of the tropospheric ozone and nitrogen dioxide (NO2) columns over mainland Greece, by using observations carried out by satellite-borne instrumentation and Multi Sensor Reanalysis. The results obtained show that the tropospheric ozone residual (TOR) dispersed farther away than the tropospheric NO2 column (TNO), due to the longer TOR's lifetime in respect to that of TNO. This results in the influence of the air quality of the nearby southern islands from the air pollution of the greater Athens basin. Furthermore, the TOR and TNO columns over Athens, for the period October 2004 to December 2011 were found to be negatively correlated with a correlation coefficient -0.85, in contrast to recent findings which suggested strong positive correlation. Interestingly, this strong negative correlation into a slight positive correlation when the TNO concentration becomes higher than around 4 × 1015 molec cm-2, thus being best fitted by a quadratic relationship. In addition, the temporal evolution of TOR during 1979-1993 showed a decline of 0.2% per decade and just after 1993 it seems to obey a positive trend of 0.1% per decade, thus recovering during the period 1993-2011 almost 63% of the lost TOR amounts through the years 1979-1993. Finally, the association between TOR, the total ozone column (TOZ), the tropopause height and the outgoing longwave radiation (OLR) is presented by analysing observations during 1979-2011. An unexpected positive correlation between OLR and TOR was found, which may probably be attributed to the fact that enhanced abundance in tropospheric water vapor reduces the summertime TOR maximum by destructing ozone in the lower and middle troposphere through uptake mechanisms, thus emitting higher amounts of longwave radiation upwards.

  3. Ambient fine particulate matter, nitrogen dioxide, and hypertensive disorders of pregnancy in New York City

    PubMed Central

    Savitz, David A.; Elston, Beth; Bobb, Jennifer F.; Clougherty, Jane E.; Dominici, Francesca; Ito, Kazuhiko; Johnson, Sarah; McAlexander, Tara; Ross, Zev; Shmool, Jessie L.C.; Matte, Thomas D.; Wellenius, Gregory A.

    2016-01-01

    BACKGROUND Previous studies suggested a possible association between fine particulate matter air pollution (PM2.5) and nitrogen dioxide (NO2) and the development of hypertensive disorders of pregnancy, but effect sizes have been small and methodologic weaknesses preclude firm conclusions. METHODS We linked birth certificates in New York City in 2008-2010 to hospital discharge diagnoses and estimated air pollution exposure based on maternal address. The New York City Community Air Survey provided refined estimates of PM2.5 and NO2 at the maternal residence. We estimated the association between exposures to PM2.5 and NO2 in the first and second trimester and risk of gestational hypertension, mild preeclampsia, and severe preeclampsia among 268,601 births. RESULTS In unadjusted analyses, we found evidence of a positive association between both pollutants and gestational hypertension. However, after adjustment for individual covariates, socioeconomic deprivation, and delivery hospital, we did not find evidence of an association between PM2.5 or NO2 in the first or second trimester and any of the outcomes. CONCLUSIONS Our data did not provide clear evidence of an effect of ambient air pollution on hypertensive disorders of pregnancy. Results need to be interpreted with caution considering the quality of the available exposure and health outcome measures and the uncertain impact of adjusting for hospital. Relative to previous studies, which have tended to identify positive associations with PM2.5 and NO2, our large study size, refined air pollution exposure estimates, hospital-based disease ascertainment, and little risk of confounding by socioeconomic deprivation, does not provide evidence for an association. PMID:26237745

  4. Associations between daily mortality in London and combined oxidant capacity, ozone and nitrogen dioxide.

    PubMed

    Williams, M L; Atkinson, R W; Anderson, H R; Kelly, F J

    2014-01-01

    Both nitrogen dioxide (NO2) and ozone (O3) are powerful oxidants in ambient air that are intimately linked through atmospheric chemistry and which continuously interchange over very short timescales. Based upon atmospheric chemistry alone, there is a strong, a priori, reason for considering O3 and NO2 together in epidemiological studies, rather than either of the two pollutants separately in single-pollutant models. This paper compares two approaches to this, using Ox, defined as O3 + NO2, as a single metric and also using O3 and NO2 together in two-pollutant models. We hypothesised that the magnitude of the association between Ox and daily mortality would be greater than for NO2 and O3 individually. Using collocated hourly measurements for O3 and NO2 in London, from 2000 to 2005, we carried out a time series analysis of daily mortality. We investigated O3, NO2 and Ox individually in single-pollutant Poisson regression models and NO2 and O3 jointly in two-pollutant models in both all-year and season-specific analyses. We observed larger associations for mean 24-h concentrations of Ox (1.30 % increase in mortality per 10 ppb) than for O3 (0.87 %) and NO2 (0 %) individually. However, when analysed jointly in two-pollutant models, associations for O3 (1.54 %) and NO2 (1.07 %) were comparable to the Ox association. Season-specific analyses broadly followed this pattern irrespective of whether the Ox concentrations were driven by O3 production (summer) or depletion (winter). This novel approach in air pollution epidemiology captures the simultaneous impact of both oxidants whilst avoiding many of the statistical issues associated with two-pollutant models and potentially simplifies health impact calculations. PMID:25431629

  5. Activity pattern and personal exposure to nitrogen dioxide in indoor and outdoor microenvironments.

    PubMed

    Kornartit, C; Sokhi, R S; Burton, M A; Ravindra, Khaiwal

    2010-01-01

    People are exposed to air pollution from a range of indoor and outdoor sources. Concentrations of nitrogen dioxide (NO(2)), which is hazardous to health, can be significant in both types of environments. This paper reports on the measurement and analysis of indoor and outdoor NO(2) concentrations and their comparison with measured personal exposure in various microenvironments during winter and summer seasons. Furthermore, the relationship between NO(2) personal exposure in various microenvironments and including activities patterns were also studied. Personal, indoor microenvironments and outdoor measurements of NO(2) levels were conducted using Palmes tubes for 60 subjects. The results showed significant differences in indoor and outdoor NO(2) concentrations in winter but not for summer. In winter, indoor NO(2) concentrations were found to be strongly correlated with personal exposure levels. NO(2) concentration in houses using a gas cooker was higher in all rooms than those with an electric cooker during the winter campaign, whereas there was no significant difference noticed in summer. The average NO(2) levels in kitchens with a gas cooker were twice as high as those with an electric cooker, with no significant difference in the summer period. A time-weighted average personal exposure was calculated and compared with measured personal exposures in various indoor microenvironments (e.g. front doors, bedroom, living room and kitchen); including non-smokers, passive smokers and smoker. The estimated results were closely correlated, but showed some underestimation of the measured personal exposures to NO(2) concentrations. Interestingly, for our particular study higher NO(2) personal exposure levels were found during summer (14.0+/-1.5) than winter (9.5+/-2.4).

  6. Nitrogen Dioxide and Allergic Sensitization in the 2005–2006 National Health and Nutrition Examination Survey

    PubMed Central

    Weir, Charles H.; Yeatts, Karin B.; Sarnat, Jeremy A.; Vizuete, William; Salo, Päivi M.; Jaramillo, Renee; Cohn, Richard D.; Chu, Haitao; Zeldin, Darryl C.; London, Stephanie J.

    2014-01-01

    Background Allergic sensitization is a risk factor for asthma and allergic diseases. The relationship between ambient air pollution and allergic sensitization is unclear. Objective To investigate the relationship between ambient air pollution and allergic sensitization in a nationally representative sample of the US population. Methods We linked annual average concentrations of nitrogen dioxide (NO2), particulate matter ≤ 10 µm (PM10), particulate matter ≤ 2.5 µm (PM25), and summer concentrations of ozone (O3), to allergen-specific immunoglobulin E (IgE) data for participants in the 2005–2006 National Health and Nutrition Examination Survey (NHANES). In addition to the monitor-based air pollution estimates, we used the Community Multiscale Air Quality (CMAQ) model to increase the representation of rural participants in our sample. Logistic regression with population-based sampling weights was used to calculate adjusted prevalence odds ratios per 10 ppb increase in O3 and NO2, per 10 µg/m3 increase in PM10, and per 5 µg/m3 increase in PM2.5 adjusting for race, gender, age, socioeconomic status, smoking, and urban/rural status. Results Using CMAQ data, increased levels of NO2 were associated with positive IgE to any (OR 1.15, 95% CI 1.04, 1.27), inhalant (OR 1.17, 95% CI 1.02, 1.33), and outdoor (OR 1.16, 95% CI 1.03, 1.31) allergens. Higher PM2.5 levels were associated with positivity to indoor allergen-specific IgE (OR 1.24, 95% CI 1.13, 1.36). Effect estimates were similar using monitored data. Conclusions Increased ambient NO2 was consistently associated with increased prevalence of allergic sensitization. PMID:24045117

  7. Sources of variation for indoor nitrogen dioxide in rural residences of Ethiopia

    PubMed Central

    2009-01-01

    Background Unprocessed biomass fuel is the primary source of indoor air pollution (IAP) in developing countries. The use of biomass fuel has been linked with acute respiratory infections. This study assesses sources of variations associated with the level of indoor nitrogen dioxide (NO2). Materials and methods This study examines household factors affecting the level of indoor pollution by measuring NO2. Repeated measurements of NO2 were made using a passive diffusive sampler. A Saltzman colorimetric method using a spectrometer calibrated at 540 nm was employed to analyze the mass of NO2 on the collection filter that was then subjected to a mass transfer equation to calculate the level of NO2 for the 24 hours of sampling duration. Structured questionnaire was used to collect data on fuel use characteristics. Data entry and cleaning was done in EPI INFO version 6.04, while data was analyzed using SPSS version 15.0. Analysis of variance, multiple linear regression and linear mixed model were used to isolate determining factors contributing to the variation of NO2 concentration. Results A total of 17,215 air samples were fully analyzed during the study period. Wood and crop were principal source of household energy. Biomass fuel characteristics were strongly related to indoor NO2 concentration in one-way analysis of variance. There was variation in repeated measurements of indoor NO2 over time. In a linear mixed model regression analysis, highland setting, wet season, cooking, use of fire events at least twice a day, frequency of cooked food items, and interaction between ecology and season were predictors of indoor NO2 concentration. The volume of the housing unit and the presence of kitchen showed little relevance in the level of NO2 concentration. Conclusion Agro-ecology, season, purpose of fire events, frequency of fire activities, frequency of cooking and physical conditions of housing are predictors of NO2 concentration. Improved kitchen conditions and

  8. The Effects of Nitrogen Enrichment and a Simulated Rainfall Event on Soil Carbon Dioxide Efflux in an Annual California Grassland

    NASA Astrophysics Data System (ADS)

    Johnson, T. P.; Strong, A. L.; Chiariello, N.; Field, C. B.

    2013-12-01

    Soils contain the largest pool of carbon in terrestrial ecosystems and play a critical role in the global carbon cycle. Previous studies have shown that enhanced precipitation (projected by climate models) and human activities (such as increased fertilizer use) may alter this cycle by enhancing soil microbial activity, although effects are often variable. Soils in semi-arid grasslands play a vital role in the global carbon cycle and may be responsive to environmental perturbations. Previous studies have demonstrated that wet-up treatments positively influence soil carbon dioxide efflux rates, which are otherwise low during dry summers. A preliminary study performed in a semi-arid annual grassland has shown that long-term nitrogen enrichment (equivalent to 70kg N per hectare) positively influences soil carbon dioxide efflux during peak biomass in the wet season. However, the combined effect and seasonal dynamics of these environmental changes is poorly understood. In order to assess this interaction, we explore the short-term response of soil carbon dioxide efflux rates in a semi-arid grassland to a combination of long-term nitrogen enrichment and a simulated 20-mm rainfall event in the Jasper Ridge Global Change Experiment (JRCGE), a long-term, multi-factorial experiment in a semi-arid annual grassland located in the foothills of the Santa Cruz mountains in central California. We measured soil carbon dioxide efflux rates from pre-installed soil respiration collars for forty-eight hours after a simulated rainfall event (20mm) during the dry season in late July 2013. Both the enhanced and non-enhanced nitrogen treatments had an immediate pronounced response to the wet-up stimulation in which efflux rates increased by an average of more than six-fold. In contrast with previous studies of soil carbon dioxide efflux at JRGCE during the wet season in which N enrichment elevated efflux rates relative to controls, however, the soil carbon dioxide efflux rates in response

  9. Powder containing 2H-type silicon carbide produced by reacting silicon dioxide and carbon powder in nitrogen atmosphere in the presence of aluminum

    NASA Technical Reports Server (NTRS)

    Kuramoto, N.; Takiguchi, H.

    1984-01-01

    The production of powder which contains silicon carbide consisting of 40% of 2H-type silicon carbide, beta type silicon carbide and less than 3% of nitrogen is discussed. The reaction temperature to produce the powder containing 40% of 2H-type silicon carbide is set at above 1550 degrees C in an atmosphere of aluminum or aluminum compounds and nitrogen gas or an antioxidation atmosphere containing nitrogen gas. The mixture ratio of silicon dioxide and carbon powder is 0.55 - 1:2.0 and the contents of aluminum or aluminum compounds within silicon dioxide is less than 3% in weight.

  10. Evaluation of a chlorous acid-chlorine dioxide teat dip under experimental and natural exposure conditions.

    PubMed

    Drechsler, P A; Wildman, E E; Pankey, J W

    1990-08-01

    A postmilking teat dip containing chlorous acid-chlorine dioxide was evaluated by experimental challenge and in two herds under natural exposure. The test product had an efficacy of 78.9% against Staphylococcus aureus and 52.5% against Streptococcus agalactiae in the experimental challenge trial. The product was compared with a 1% iodine product in a 15-mo natural exposure study. Post-dipping with chlorous acid-chlorine dioxide reduced incidence of udder infection by major mastitis pathogens 36.1% when data were combined from the two herds. The 1% iodine and the chlorous acid-chlorine dioxide products were not equivalent for major mastitis pathogens; the test product was more effective. Incidence of udder infection by environmental mastitis pathogens was reduced 36.8% in both herds combined. Efficacy of the two teat dips was equivalent for environmental pathogens. PMID:2229601

  11. Citizen science identifies the effects of nitrogen dioxide and other environmental drivers on tar spot of sycamore.

    PubMed

    Gosling, Laura; Ashmore, Mike; Sparks, Tim; Bell, Nigel

    2016-07-01

    Elevated sulphur dioxide (SO2) concentrations were the major cause of the absence of symptoms of tar spot (Rhytisma acerinum) of sycamore (Acer pseudoplatanus), in urban areas in the 1970s. The subsequent large decline in SO2 concentrations has not always been accompanied by increased tar spot symptoms, for reasons that have remained unresolved. We used a large citizen science survey, providing over 1000 records across England, to test two competing hypotheses proposed in earlier studies. We were able to demonstrate the validity of both hypotheses; tar spot symptoms were reduced where there were fewer fallen leaves as a source of inoculum, and elevated nitrogen dioxide concentrations reduced tar spot symptoms above a threshold concentration of about 20 μg m(-3). Symptom severity was also lower at sites with higher temperature and lower rainfall. Our findings demonstrate the power of citizen science to resolve competing hypotheses about the impacts of air pollution and other environmental drivers.

  12. The impact of titanium dioxide nanoparticles on biological nitrogen removal from wastewater and bacterial community shifts in activated sludge.

    PubMed

    Li, Dapeng; Cui, Fuyi; Zhao, Zhiwei; Liu, Dongmei; Xu, Yongpeng; Li, Huiting; Yang, Xiaonan

    2014-04-01

    The potential impact of titanium dioxide nanoparticles (TiO2 NPs) on nitrogen removal from wastewater in activated sludge was investigated using a sequencing batch reactor. The addition of 2-50 mg L(-1) of TiO2 NPs did not adversely affect nitrogen removal. However, when the activated sludge was exposed to 100-200 mg L(-1) of TiO2 NPs, the effluent total nitrogen removal efficiencies were 36.5 % and 20.3 %, respectively, which are markedly lower than the values observed in the control test (80 %). Further studies showed that the decrease in biological nitrogen removal induced by higher concentrations of TiO2 NPs was due to an inhibitory effect on the de-nitrification process. Denaturing gradient gel electrophoresis profiles showed that 200 mg L(-1) of TiO2 NPs significantly reduced microbial diversity in the activated sludge. The effect of light on the antibacterial activity of TiO2 NPs was also investigated, and the results showed that the levels of TiO2-dependent inhibition of biological nitrogen removal were similar under both dark and light conditions. Additional studies revealed that different TiO2 concentrations had a significant effect on dehydrogenase activity, and this effect was most likely the result of decreased microbial activity. PMID:23660752

  13. Recent advances in nitrogen-fixing acetic acid bacteria.

    PubMed

    Pedraza, Raúl O

    2008-06-30

    Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects

  14. Detection of atmospheric nitrogen dioxide using a miniaturised fibre-optic spectroscopy system and the ambient sunlight.

    PubMed

    Morales, J A; Walsh, J E

    2005-07-01

    A miniaturised fibre-optic spectrometer based system is presented for direct detection of one of the major atmospheric pollutants, nitrogen dioxide, by absorption spectroscopy using the ambient sunlight as light source. The detection system consists of a 10 cm collimator assembly, a fibre-optic cable and a portable diode-array spectrometer. The absorbance spectrum of the open-path is calculated using a reference spectrum recorded when the nitrogen dioxide (NO2) concentration in the atmosphere is low. The relative concentration of the pollutant is calculated normalising the detected spectra and subtracting the background broadband spectrum from the specific NO2 absorbance features, since the broadband spectrum changes according to atmospheric conditions and solar intensity. Wavelengths between 400 and 500 nm are used in order to maximise sensitivity and to avoid interference from other species. Calibration is carried out using Tedlar sample bags of known concentration of the pollutant. A commercial differential optical absorption spectroscopy (DOAS) system is used as a reference standard detection system to compare the results with the new system. Results show that detection of NO2 at typical urban atmospheric levels has been achieved using an inexpensive field based fibre-optic spectrometer and a readily available, easy to align, light source. In addition the new system can be used to get a semi-quantitative estimation of the nitrogen dioxide concentration within errors of 20%. While keeping the typical benefits of open-path techniques, the new system has important advantages over them such as cost, simplicity and portability. PMID:15911394

  15. Improved spectral fitting of nitrogen dioxide from OMI in the 405-465 nm window

    NASA Astrophysics Data System (ADS)

    van Geffen, J. H. G. M.; Boersma, K. F.; Van Roozendael, M.; Hendrick, F.; Mahieu, E.; De Smedt, I.; Sneep, M.; Veefkind, J. P.

    2015-04-01

    An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405-465 nm spectral region is presented. Since the launch of OMI on board NASA's EOS-Aura satellite in 2004, differential optical absorption spectroscopy (DOAS) retrievals of NO2 slant column densities have been the starting point for the KNMI DOMINO and NASA SP NO2 vertical column data as well as the OMI NO2 data of some other institutes. However, recent intercomparisons between NO2 retrievals from OMI and other UV/Vis and limb spectrometers, as well as ground-based measurements, suggest that OMI stratospheric NO2 is biased high. This study revises and, for the first time, fully documents the OMI NO2 retrieval in detail. The representation of the OMI slit function to convolve high-resolution reference spectra onto the relevant spectral grid is improved. The window used for the wavelength calibration is optimised, leading to much-reduced fitting errors. Ozone and water vapour spectra used in the fit are updated, reflecting the recently improved knowledge of their absorption cross section in the literature. The improved spectral fit also accounts for absorption by the O2-O2 collision complex and by liquid water over clear-water areas. The main changes in the improved spectral fitting result from the updates related to the wavelength calibration: the RMS error of the fit is reduced by 23% and the NO2 slant column by 0.85 × 1015 molec cm-2, independent of latitude, solar zenith angle and NO2 value. Including O2-O2 and liquid water absorption and updating the O3 and water vapour cross-section spectra further reduces NO2 slant columns on average by 0.35 × 1015 molec cm-2, accompanied by a further 9% reduction in the RMS error of the fit. The improved OMI NO2 slant columns are consistent with independent NO2 retrievals from other instruments to within a range that can be explained by photochemically driven diurnal increases in stratospheric NO2 and by

  16. Improved spectral fitting of nitrogen dioxide from OMI in the 405-465 nm window

    NASA Astrophysics Data System (ADS)

    van Geffen, J. H. G. M.; Boersma, K. F.; Van Roozendael, M.; Hendrick, F.; Mahieu, E.; De Smedt, I.; Sneep, M.; Veefkind, J. P.

    2014-10-01

    An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405-465 nm spectral region is presented. Since the launch of OMI on board NASA's EOS-Aura satellite in 2004, DOAS retrievals of NO2 slant column densities have been the starting point for the KNMI DOMINO (v2.0) and NASA SP (v2.1) retrievals. However, recent intercomparisons between NO2 retrievals from OMI and other UV/Vis and limb spectrometers, as well as ground-based measurements, clearly suggested that OMI stratospheric NO2 is biased high. This study revises the OMI NO2 retrieval in detail. The representation of the OMI slit function to convolve high-resolution reference spectra onto the relevant spectral grid is improved. The window used for the wavelength calibration is optimised, leading to much-reduced fitting errors. Ozone and water vapour spectra used in the fit are updated, reflecting the recently improved knowledge on their absorption cross section as documented in the literature. The improved spectral fit also accounts for absorption by the O2-O2 collision complex and by liquid water over clear-water areas. The main changes in the improved spectral fitting result from the updates related to the wavelength calibration: the RMS error of the fit is reduced by 23% and the NO2 slant column by 0.85 × 1015 molec cm-2, independent of latitude, solar zenith angle and NO2 value. Including O2-O2 and liquid water absorption and updating the O3 and water vapour cross-section spectra further reduces NO2 slant columns on average by 0.35 × 1015 molec cm-2, accompanied with a further 9% reduction in the RMS error of the fit. The improved OMI NO2 slant columns are consistent with independent NO2 retrievals to within a range that can be explained by photo-chemically driven diurnal increases in stratospheric NO2 and by small differences in fitting window and fitting approach. The revisions indicate that current OMI NO2 slant columns suffered mostly from an

  17. Mass transfer phenomena of gaseous hydrocarbons and nitrogen dioxide across gas-inorganic pigments boundaries

    NASA Astrophysics Data System (ADS)

    Birbatakou, S.; Pagopoulou, I.; Kalantzopoulos, A.; Roubani-Kalantzopoulou, F.

    1998-11-01

    Reversed-flow gas chromatography was used to study the kinetics of the action of five hydrocarbons namely, ethane, ethene, ethyne, propene and butene and of the nitrogen dioxide, on three known and widely used pigments, the white one TiO2, and the yellows CdS and PbCrO4. The calculation of kinetic parameters and mass transfer coefficients is based on an experimental adsorption isotherm. All these calculations are based on a non linear adsorption isotherm model as it is well accepted that the linear one is inadequate for inorganic substances like these mentioned in this work. The inadequacy is mainly attributed to the non-uniformity of the solid surface. Five physicochemical parameters have been obtained for each of the twenty heterogeneous reactions studied. With these systematic experiments under conditions which are similar to the atmospheric ones, an extrapolation of the results obtained to “real" atmospheres with a high degree of confidence is possible. Some of the calculations were based on the linear model for comparison. La cinétique de la réaction de cinq hydrocarbures (éthane, éthylène, acétylène, propène, boutène) et du dioxyde d'azote avec trois pigments (le blanc de TiO2 et les jaunes de CdS et PbCrO4) a été étudiée par chromatographie en phase gazeuse a flux inversé. Le calcul des paramètres cinétiques et des coefficients de transfert de masse a été effectué à partir des isothermes d'adsorption expérimentales en faisant l'hypothèse d`un modèle d'adsorption non-linéaire, qui résulte de la non-uniformité de la surface. Cinq paramètres physico-chimiques ont été obténus pour chacune des vingt réaction hétérogènes étudiées. À partir de ces résultats obténus dans des conditions similaires aux conditions atmosphériques, l'extrapolation à des atmosphères réelles paraît possible avec une bonne confiance. Quelques calculs ont été effectués avec un modèle linéaire pour comparaison.

  18. Effect of nitrogen dioxide, ozone, and peroxyacetyl nitrate on metabolic and pulmonary function

    SciTech Connect

    Drechsler-Parks, D.M. )

    1987-04-01

    The metabolic and pulmonary function responses were investigated in 32 non-smoking men and women (8 men and 8 women 18-26 years of age, and 8 men and 8 women 51-76 years of age) who were exposed for 2 hours to each of 8 conditions: (1) filtered air (FA), (2) 0.13 ppm peroxyacetyl nitrate (PAN), (3) 0.45 ppm ozone (O3), (4) 0.60 ppm nitrogen dioxide (NO2), (5) 0.13 ppm PAN + 0.45 ppm O3 (PAN/O3), (6) 0.13 ppm PAN + 0.60 ppm NO2 (PAN/NO2), (7) 0.60 ppm NO2 + 0.45 ppm O3 (NO2/O3), and (8) 0.13 ppm PAN + 0.60 ppm NO2 + 0.45 ppm O3 (PAN/NO2/O3). The subjects alternated 20-min periods of rest (n = 3) and cycle ergometer exercise (n = 3) at a work load predetermined to elicit a ventilatory minute volume (VE) of approximately 25 L/min (BTPS). Functional residual capacity (FRC) was determined pre- and post-exposure. Forced vital capacity (FVC) was determined before and after exposure, and 5 min after each exercise period. Heart rate was monitored throughout each exposure, and VE was measured during the last 2 min of each exercise period. Exposure to FA, PAN, NO2, and PAN/NO2 had no effect on any measure of pulmonary or metabolic function. Ozone was primarily responsible for the pulmonary function effects observed. There was no significant difference between the responses to O3 exposure and the responses to the three O3 mixtures, indicating no interactions between the pollutants. The results suggest that women may be somewhat more responsive to O3 exposure than men, and that older people (51-76 years of age) may be less responsive to O3 than younger people (18-26 years of age).

  19. Rapid growth in nitrogen dioxide pollution over Western China, 2005-2013

    NASA Astrophysics Data System (ADS)

    Cui, Y.-Z.; Lin, J.-T.; Song, C.; Liu, M.-Y.; Yan, Y.-Y.; Xu, Y.; Huang, B.

    2015-12-01

    Western China has experienced rapid industrialization and urbanization since the implementation of the National Western Development Strategies (the "Go West" movement) in 1999. This transition has affected the spatial and temporal characteristics of nitrogen dioxide (NO2) pollution. In this study, we analyze the trends and variability of tropospheric NO2 vertical column densities (VCDs) from 2005 to 2013 over Western China, based on a wavelet analysis on monthly mean NO2 data derived from the Ozone Monitoring Instrument (OMI) measurements. We focus on the anthropogenic NO2 by subtracting region-specific "background" values dominated by natural sources. We find significant NO2 growth over Western China between 2005 and 2013 (8.6 ± 0.9 % yr-1 on average, relative to 2005), with the largest increments (15 % yr-1 or more) over parts of several city clusters. The NO2 pollution in most provincial regions rose rapidly from 2005 to 2011 but stabilized or declined afterwards. The NO2 trends were driven mainly by changes in anthropogenic emissions, as confirmed by a nested GEOS-Chem model simulation and a comparison with Chinese official emission statistics. The rate of NO2 growth during 2005-2013 reaches 11.3 ± 1.0 % yr-1 over Northwestern China, exceeding the rates over Southwestern China (5.9 ± 0.6 % yr-1) and the three well-known polluted regions in the east (5.3 ± 0.8 % yr-1 over Beijing-Tianjin-Hebei, 4.0 ± 0.6 % yr-1} over the Yangtze River Delta, and -3.3 ± 0.3 % yr-1 over the Pearl River Delta). Additional socioeconomic analyses suggest that the rapid NO2 growth in Northwestern China is likely related to the fast developing resource- and pollution-intensive industries along with the "Go West" movement as well as relatively weak emission controls. Further efforts should be made to alleviate NOx pollution to achieve sustainable development in Western China.

  20. Rapid growth in nitrogen dioxide pollution over Western China, 2005-2013

    NASA Astrophysics Data System (ADS)

    Cui, Yuanzheng; Lin, Jintai; Song, Chunqiao; Liu, Mengyao; Yan, Yingying; Xu, Yuan; Huang, Bo

    2016-05-01

    Western China has experienced rapid industrialization and urbanization since the implementation of the National Western Development Strategies (the "Go West" movement) in 1999. This transition has affected the spatial and temporal characteristics of nitrogen dioxide (NO2) pollution. In this study, we analyze the trends and variability of tropospheric NO2 vertical column densities (VCDs) from 2005 to 2013 over Western China, based on a wavelet analysis on monthly mean NO2 data derived from the Ozone Monitoring Instrument (OMI) measurements. We focus on the anthropogenic NO2 by subtracting region-specific "background" values dominated by natural sources. After removing the background influences, we find significant anthropogenic NO2 growth over Western China between 2005 and 2013 (8.6 ± 0.9 % yr-1 on average, relative to 2005), with the largest increments (15 % yr-1 or more) over parts of several city clusters. The NO2 pollution in most provincial-level regions rose rapidly from 2005 to 2011 but stabilized or declined afterwards. The NO2 trends were driven mainly by changes in anthropogenic emissions, as confirmed by a nested GEOS-Chem model simulation and a comparison with Chinese official emission statistics. The rate of NO2 growth during 2005-2013 reaches 11.3 ± 1.0 % yr-1 over Northwestern China, exceeding the rates over Southwestern China (5.9 ± 0.6 % yr-1) and the three well-known polluted regions in the east (5.3 ± 0.8 % yr-1 over Beijing-Tianjin-Hebei, 4.0 ± 0.6 % yr-1 over the Yangtze River Delta, and -3.3 ± 0.3 % yr-1 over the Pearl River Delta). Subsequent socioeconomic analyses suggest that the rapid NO2 growth over Northwestern China is likely related to the fast developing resource- and pollution-intensive industries along with the "Go West" movement as well as relatively weak emission controls. Further efforts should be made to alleviate NOx pollution to achieve sustainable development in Western China.

  1. Indoor-outdoor relationships of airborne particles and nitrogen dioxide inside Parisian buses

    NASA Astrophysics Data System (ADS)

    Molle, Romain; Mazoué, Sophie; Géhin, Évelyne; Ionescu, Anda

    2013-04-01

    This study evaluated passengers' exposure to traffic air pollution inside the articulated buses of the line 91 in Paris during 10 working days in May, 2010. Twenty articulated buses were studied on 32 routes in order to determine the influence of the sampling position on the pollutant concentrations. This parameter is still poorly known for the rigid buses and is even less known for the articulated ones. However this parameter must be studied for articulated buses because the greater length may cause a pollutant concentration gradient in the cabin. Portable devices were used to measure pollutants in the presence of passengers from 8 a.m. to 9 a.m. and from 4 p.m. to 5 p.m., time periods corresponding to the peak traffic and travellers. PM2.5 mass concentration, particle number concentration between 0.3 and 20 μm and nitrogen dioxide concentration were simultaneously measured on three positions inside the buses (front, middle and rear) in order to study the spatial distribution of these compounds. These measurements inside the buses were compared to the outdoor concentrations at the same moment of the day provided by the Parisian air quality monitoring network; they were also compared to the results of a previous monitoring campaign performed in 2008. The results obtained during the 2010 campaign revealed that in-cabin NO2 mean concentrations were 1.5-3.5 times higher than the outside concentration levels; a maximum concentration of 234 ± 40 μg m-3 was found in the rear position (location of the engine and exhaust gas). Mean in-cabin PM2.5 mass concentrations varied from one week to another one, but they were globally the same at the three positions inside the instrumented buses. In order to determine the impact of outdoor levels, correlations have been calculated between the results measured inside the buses and those measured by the outdoor air monitoring stations. The highest Pearson correlation coefficient was 0.29 for NO2 data whereas the highest Pearson

  2. Broadband cavity enhanced spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Attwood, A. R.; Flores, J. M.; Rudich, Y.; Brown, S. S.

    2015-09-01

    Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity enhanced spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99933 ± 0.00003 (670 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.49 km within the 1 m cell. We measure the cavity output over the 315-350 nm spectral region using a grating monochromator and charge-coupled device (CCD) array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity enhanced spectroscopy and cavity ringdown spectroscopy agree within 2 % (slope for linear fit = 0.98 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity enhanced spectroscopy and calculated based on flow dilution are also well-correlated, with r2 = 0.9998. During constant, mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1-min detection limit for extinction measurements at 315-350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically-based trace gas detection that may complement higher precision techniques based on non-absolute detection methods. In addition to trace gases, this approach will be appropriate for

  3. Partial oxidation of methane to methanol with nitrogen dioxide in dielectric barrier discharge plasma: experimental and molecular modeling

    NASA Astrophysics Data System (ADS)

    Indarto, Antonius

    2016-04-01

    Non-catalytic conversion of methane (CH4) and nitrogen dioxide (NO2) into methanol (CH3OH) has been conducted and presented in this paper. Experiments were carried out using dielectric barrier discharge as the reaction medium in atmospheric pressure and temperature conditions. High yield production of methanol was achieved (18-20% mol) by single-stage plasma reaction with maximum selectivity of 32% mol. Compared to other oxidants, such as O2, the presence of NO2 in the plasma reaction resulted in higher methanol selectivity. For better understanding of the reactions, density functional theory calculations were also performed and discussed.

  4. Short-term exposure to 0. 3 ppm nitrogen dioxide does not potentiate airway responsiveness to sulfur dioxide in asthmatic subjects

    SciTech Connect

    Rubinstein, I.; Bigby, B.G.; Reiss, T.F.; Boushey, H.A. Jr. )

    1990-02-01

    Whether short-term exposure to low levels of nitrogen dioxide (NO2) enhances airway responsiveness in asthmatic subjects is controversial. Because it is well established that asthma is associated with increased airway responsiveness to another common air pollutant, sulfur dioxide (SO2), we examined whether short-term exposure of asthmatic subjects to 0.3 ppm NO2 potentiates airway responsiveness to inhaled SO2. We exposed nine subjects with clinically stable asthma to 0.3 ppm NO2 or filtered air in an environmental room for 30 min on 2 separate days at least 1 wk apart in a double-blind, randomized fashion. A questionnaire about common symptoms related to inhaled irritants was completed before and immediately after each exposure. Each subject exercised (60 to 80 W) on a cycloergometer during the first 20 min of each exposure. We measured specific airway resistance (SRaw) and FEV1/FVC before, 5 min after, and 1 h after completion of the air or NO2 exposure. The single-breath nitrogen test (SBN2) was also performed before and 1 h after completion of the air or NO2 exposures and closing volume was determined; subsequently, SO2 dose-response curves (0.25 to 4.0 ppm) were performed via a mouthpiece. Each dose of SO2 was inhaled at a minute ventilation of 20 L/min for 4 min and was doubled until SRaw increased by at least 8 U above baseline. The dose of SO2 required to provoke an increase in SRaw of 8 U above baseline was determined by linear interpolation from the dose-response curve (PD8Uso2).

  5. Responses of two summer annuals to interactions of atmospheric carbon dioxide and soil nitrogen

    SciTech Connect

    Thomas, R.B.

    1987-01-01

    The competitive relationship between Chenopodium album L. (C{sub 3}) and Amaranthus hybridus L. (C{sub 4}) was investigated in two atmospheric CO{sub 2} levels and tow soil nitrogen levels. Biomass and leaf surface area of Amaranthus plants did not respond to CO{sub 2} enrichment. Only in high nitrogen did Chenopodium plants respond to increased CO{sub 2} with greater biomass and leaf surface area. Nitrogen use efficiency (NUE) was higher in Amaranthus than in Chenopodium in all treatments except for the high-nitrogen high-CO{sub 2} treatment. Under conditions of high nitrogen and low CO{sub 2}, Chenopodium was a poor competitor, but competition favored Chenopodium in high nitrogen and high CO{sub 2}. In low nitrogen and high CO{sub 2}, competition favored Chenopodium on a dry weight basis, but favored Amaranthus on a seed weight basis, reflecting early senescence of Chenopodium. In low nitrogen and high CO{sub 2}, competition favored Amaranthus on a dry weight basis, but favored Chenopodium on a seed weight basis. Physiological aspects of the growth of Chenopodium and Amaranthus were studied. Acclimation to elevated CO{sub 2} occurred at the enzyme level in Chenopodium. Under conditions of high nitrogen and no competition, individual Chenopodium plants responded to elevated CO{sub 2} with greater biomass, leaf surface area, and maximum net photosynthetic rates. In high nitrogen, leaf nitrogen, soluble protein, and RuBP carboxylase activity of Chenopodium decreased and NUE increased when grown in elevated CO{sub 2}. In low nitrogen without competition, Chenopodium showed no significant response to CO{sub 2} enrichment. Amarantus grown in high and low nitrogen without competition showed no significant changes in leaf nitrogen, soluble protein, carboxylase activity, chlorophyll, or NUE of in response to CO{sub 2} enrichment.

  6. Effects of nitrogen dioxide on growth and yield of black turtle bean (Phaseolus vulgaris L.) cv. 'Domino'.

    PubMed

    Sandhu, R; Gupta, G

    1989-01-01

    Twenty-six-day-old black turtle bean cv. 'Domino' plants were exposed to nitrogen dioxide (0.0, 0.025, 0.05 and 0.10 microl liter(-1)), 7 h per day for 5 days per week for 3 weeks, under controlled environment. Data were collected on net photosynthesis rate (PN), stomatal resistance (SR), and dark respiration rate (DR), immediately after exposure, 24 h after the termination of exposure and at maturity (when the leaves had just started turning yellow), using a LICOR 6000 Portable Photosynthesis System. Chlorophyll-a (Ch-a), chlorophyll-b (Ch-b), total chlorophyll (tot-Ch) and leaf nitrogen were measured immediately after exposure and at maturity. Growth characteristics-relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and root: shoot ratio (RSR)-were computed for treated plants. Net photosynthesis rate increased by 53% in 0.10 microl liter(-1) NO2 treated plants immediately after exposure compared to control plants. Dark respiration rates were also higher in treated plants. Ch-a, Ch-b and tot-Ch showed significant increases with 0.1 microl liter(-1) NO2 treatment immediately after exposure. Foliar nitrogen content showed an increase in treated plants both immediately after exposure and at maturity. Increases were also seen in RGR and NAR. Plant yield increased by 86% (number of pods), 29% (number of seeds) and 46% (weight of seeds), respectively. Nitrogen dioxide stimulated the overall plant growth and crop yield. PMID:15092401

  7. Polymerization of euphorbia oil with Lewis acid in carbon dioxide media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron trifluoride diethyl etherate (BF3-OEt2) Lewis acid catalyzed ring-opening polymerization of euphorbia oil (EO), a natural epoxy oil, in liquid carbon dioxide was conducted in an effort to develop useful vegetable oil based polymers. The resulting polymers (RPEO) were characterized by FTIR, 1H-...

  8. Diffusion of cis-5,8,11,14,17-eicosapentaenoic acid (1); carbon dioxide (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) cis-5,8,11,14,17-eicosapentaenoic acid; (2) carbon dioxide

  9. Polymorph-dependent titanium dioxide nanoparticle dissolution in acidic and alkali digestions

    EPA Science Inventory

    Multiple polymorphs (anatase, brookite and rutile) of titanium dioxide nanoparticles (TiO2-NPs) with variable structures were quantified in environmental matrices via microwave-based hydrofluoric (HF) and nitric (HNO3) mixed acid digestion and muffle furnace (MF)-based potassium ...

  10. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    PubMed

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid. PMID:27542478

  11. Sensorially important aldehyde production from amino acids in model wine systems: impact of ascorbic acid, erythorbic acid, glutathione and sulphur dioxide.

    PubMed

    Grant-Preece, Paris; Fang, Hongjuan; Schmidtke, Leigh M; Clark, Andrew C

    2013-11-01

    The efficiency of different white wine antioxidant systems in preventing aldehyde production from amino acids by oxidative processes is not well understood. The aim of this study was to assess the efficiency of sulphur dioxide alone and in combination with either glutathione, ascorbic acid or its stereoisomer erythorbic acid, in preventing formation of the sensorially important compounds methional and phenylacetaldehyde from methionine and phenylalanine in model white wine. UHPLC, GC-MS/MS, LC-MS/MS, flow injection analysis and luminescence sensors determined both compositional changes during storage, and sulphur dioxide-aldehyde apparent equilibrium constants. Depending on temperature (25 or 45°C) or extent of oxygen supply, sulphur dioxide was equally or more efficient in impeding the production of methional compared to the other antioxidant systems. For phenylacetaldehyde, erythorbic acid or glutathione with sulphur dioxide provided improved inhibition compared to sulphur dioxide alone, in conditions of limited oxygen consumption. The results also demonstrate the extent to which sulphur dioxide addition can lower the free aldehyde concentrations to below their aroma thresholds.

  12. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  13. Recycling of carbon dioxide and acetate as lactic acid by the hydrogen-producing bacterium Thermotoga neapolitana.

    PubMed

    d'Ippolito, Giuliana; Dipasquale, Laura; Fontana, Angelo

    2014-09-01

    The heterotrophic bacterium Thermotoga neapolitana produces hydrogen by fermentation of sugars. Under capnophilic (carbon dioxide requiring) conditions, the process is preferentially associated with the production of lactic acid, which, as shown herein, is synthesized by reductive carboxylation of acetyl coenzyme A. The enzymatic coupling is dependent on the carbon dioxide stimulated activity of heterotetrameric pyruvate:ferredoxin oxidoreductase. Under the same culture conditions, T. neapolitana also operates the unfavorable synthesis of lactic acid from an exogenous acetate supply. This process, which requires carbon dioxide (or carbonate) and an unknown electron donor, allows for the conversion of carbon dioxide into added-value chemicals without biomass deconstruction.

  14. Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality.

    PubMed

    Llonch, P; Rodríguez, P; Gispert, M; Dalmau, A; Manteca, X; Velarde, A

    2012-04-01

    The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2; 70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The 'gas mixture' was always considered a fixed effect and the 'live weight' as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N2 and CO2 mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C

  15. Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality.

    PubMed

    Llonch, P; Rodríguez, P; Gispert, M; Dalmau, A; Manteca, X; Velarde, A

    2012-04-01

    The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2; 70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The 'gas mixture' was always considered a fixed effect and the 'live weight' as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N2 and CO2 mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C

  16. Distribution of Hydrogen Peroxide, Carbon Dioxide, and Sulfuric Acid in Europa's Icy Crust

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.

    2004-01-01

    Galileo's Near Infrared Mapping Spectrometer (NIMS) detected hydrogen peroxide, carbon dioxide and a hydrated material on Europa's surface, the latter interpreted as hydrated sulfuric acid (H2SO4*nH2O) or hydrated salts. Related compounds are molecular oxygen, sulfur dioxide, and two chromophores, one that is dark in the ultraviolet(UV) and concentrated on the trailing side, the other brighter in the UV and preferentially distributed in the leading hemisphere. The UV-dark material has been suggested to be sulfur.

  17. Nitrogen

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Ammonia was produced by 15 companies at 25 plants in 16 states in the United States during 2006. Fifty-seven percent of U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas, the dominant domestic feedstock. In 2006, U.S. producers operated at about 72 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies, Koch Nitrogen, Terra Industries, CF Industries, PCS Nitro-gen, and Agrium, in descending order, accounted for 79 percent U.S. ammonia production capacity. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  18. Evaluation of nitrogen dioxide chemiluminescence monitors in a polluted urban environment

    NASA Astrophysics Data System (ADS)

    Dunlea, E. J.; Herndon, S. C.; Nelson, D. D.; Volkamer, R. M.; San Martini, F.; Sheehy, P. M.; Zahniser, M. S.; Shorter, J. H.; Wormhoudt, J. C.; Lamb, B. K.; Allwine, E. J.; Gaffney, J. S.; Marley, N. A.; Grutter, M.; Marquez, C.; Blanco, S.; Cardenas, B.; Retama, A.; Ramos Villegas, C. R.; Kolb, C. E.; Molina, L. T.; Molina, M. J.

    2007-05-01

    Data from a recent field campaign in Mexico City are used to evaluate the performance of the EPA Federal Reference Method for monitoring the ambient concentrations of NO2. Measurements of NO2 from standard chemiluminescence monitors equipped with molybdenum oxide converters are compared with those from Tunable Infrared Laser Differential Absorption Spectroscopy (TILDAS) and Differential Optical Absorption Spectroscopy (DOAS) instruments. A significant interference in the chemiluminescence measurement is shown to account for up to 50% of ambient NO2 concentration during afternoon hours. As expected, this interference correlates well with non-NOx reactive nitrogen species (NOz) as well as with ambient O3 concentrations, indicating a photochemical source for the interfering species. A combination of ambient gas phase nitric acid and alkyl and multifunctional alkyl nitrates is deduced to be the primary cause of the interference. Observations at four locations at varying proximities to emission sources indicate that the percentage contribution of HNO3 to the interference decreases with time as the air parcel ages. Alkyl and multifunctional alkyl nitrate concentrations are calculated to reach concentrations as high as several ppb inside the city, on par with the highest values previously observed in other urban locations. Averaged over the MCMA-2003 field campaign, the chemiluminescence monitor interference resulted in an average measured NO2 concentration up to 22% greater than that from co-located spectroscopic measurements. Thus, this interference has the potential to initiate regulatory action in areas that are close to non-attainment and may mislead atmospheric photochemical models used to assess control strategies for photochemical oxidants.

  19. Evaluation of nitrogen dioxide chemiluminescence monitors in a polluted urban environment

    NASA Astrophysics Data System (ADS)

    Dunlea, E. J.; Herndon, S. C.; Nelson, D. D.; Volkamer, R. M.; San Martini, F.; Sheehy, P. M.; Zahniser, M. S.; Shorter, J. H.; Wormhoudt, J. C.; Lamb, B. K.; Allwine, E. J.; Gaffney, J. S.; Marley, N. A.; Grutter, M.; Marquez, C.; Blanco, S.; Cardenas, B.; Retama, A.; Ramos Villegas, C. R.; Kolb, C. E.; Molina, L. T.; Molina, M. J.

    2007-01-01

    Data from a recent field campaign in Mexico City are used to evaluate the performance of the EPA Federal Reference Method for monitoring ambient concentrations of NO2. Measurements of NO2 from standard chemiluminescence monitors equipped with molybdenum oxide converters are compared with those from Tunable Infrared Laser Differential Absorption Spectroscopy (TILDAS) and Differential Optical Absorption Spectroscopy (DOAS) instruments. A significant interference in the chemiluminescence measurement is shown to account for up to 50% of ambient NO2 concentration during afternoon hours. As expected, this interference correlates well with non-NOx reactive nitrogen species (NOz as well as with ambient O3 concentrations, indicating a photochemical source for the interfering species. A combination of ambient gas phase nitric acid and alkyl and multifunctional alkyl nitrates is deduced to be the primary cause of the interference. Observations at four locations at varying proximities to emission sources indicate that the percentage contribution of HNO3 to the interference decreases with time as the air parcel ages. Alkyl and multifunctional alkyl nitrate concentrations are calculated to be reach concentrations as high as several ppb inside the city, on par with the highest values previously observed in other urban locations. Averaged over the MCMA-2003 field campaign, the CL NOx monitor interference resulted in an average measured NO2 concentration up to 22% greater than that from co-located spectroscopic measurements. Thus, this interference has the potential to initiate regulatory action in areas that are close to non-attainment and may mislead atmospheric photochemical models used to assess control strategies for photochemical oxidants.

  20. Simultaneous determination of nitrogen dioxide and peroxyacetyl nitrate in ambient atmosphere by carbon-coated annular diffusion denuder

    NASA Astrophysics Data System (ADS)

    De Santis, F.; Allegrini, I.; Di Filippo, P.; Pasella, D.

    A diffusion denuder for simultaneous collection of ambient nitrogen dioxide and peroxyacetyl nitrate (PAN), based on quantitative collection on an alkaline active carbon surface, has been developed. Nitrogen dioxide yields nitrite anion whereas PAN yields nitrate which are extracted after sampling with water and analysed by ion chromatography. Laboratory and field tests concerning sorption efficiency, effect of humidity and capacity were carried out. The pre-exponential and exponent for the first term of the Gormley-Kennedy equation applied to annular geometry were estimated. It was found that for PAN the agreement between the experimental and calculated values is quite good and compatible with a "perfect sink" behaviour of carbon, whereas, in the case of NO 2, the experimental collection efficiency is lower than theory but still suitable for ambient sampling. Nitrogen oxide and ozone do not interfere in the determination. SO 2, HONO and HNO 3 which could interfere can be removed by using two diffusion denuders placed in line before the carbon denuder: one coated with tetrachloromercurate (TCM), for the removal of SO 2 and HNO 3, and the second, coated with carbonate, for the removal of HONO. The detection limit for 24 h sampling is better than 0.05 and 0.06 ppb for NO 2 and PAN, respectively. The response for NO 2 was compared during a field campaign in Milan with the corresponding integrated response of a chemiluminescence analyser, while data for PAN were compared with the integrated response of a GC-ECD technique. The results obtained are reported and discussed.

  1. Complex compound polyvinyl alcohol-titanic acid/titanium dioxide

    NASA Astrophysics Data System (ADS)

    Prosanov, I. Yu.

    2013-02-01

    A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

  2. Solubilities of stearic acid, stearyl alcohol, and arachidyl alcohol in supercritical carbon dioxide at 35[degree]C

    SciTech Connect

    Iwai, Yoshio; Koga, Yoshio; Maruyama, Hironori; Arai, Yasuhiko . Dept. of Chemical Engineering)

    1993-10-01

    The solubilities of stearic acid (octadecanoic acid), stearyl alcohol (1-octadecanol), and arachidyl alcohol (1-eicosanol) in supercritical carbon dioxide were measured by using a flow-type apparatus at 35 C up to 23.7 MPa. The solubilities of those substances and other fatty acids and higher alcohols in supercritical carbon dioxide at 35 C were correlated by a solution model based on the regular solution model coupled with the Flory-Huggins theory.

  3. Nitrogen

    USGS Publications Warehouse

    Apodaca, L.E.

    2010-01-01

    Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  4. Synthesis of polybenzoxazine based nitrogen-rich porous carbons for carbon dioxide capture

    NASA Astrophysics Data System (ADS)

    Wan, Liu; Wang, Jianlong; Feng, Chong; Sun, Yahui; Li, Kaixi

    2015-04-01

    Nitrogen-rich porous carbons (NPCs) were synthesized from 1,5-dihydroxynaphthalene, urea, and formaldehyde based on benzoxazine chemistry by a soft-templating method with KOH chemical activation. They possess high surface areas of 856.8-1257.8 m2 g-1, a large pore volume of 0.15-0.65 cm3 g-1, tunable pore structure, high nitrogen content (5.21-5.32 wt%), and high char yields. The amount of the soft-templating agent F127 has multiple influences on the textural and chemical properties of the carbons, affecting the surface area and pore structure, impacting the compositions of nitrogen species and resulting in an improvement of the CO2 capture performance. At 1 bar, high CO2 uptake of 4.02 and 6.35 mmol g-1 at 25 and 0 °C was achieved for the sample NPC-2 with a molar ratio of F127 : urea = 0.010 : 1. This can be attributed to its well-developed micropore structure and abundant pyridinic nitrogen, pyrrolic nitrogen and pyridonic nitrogen functionalities. The sample NPC-2 also exhibits a remarkable selectivity for CO2/N2 separation and a fast adsorption/desorption rate and can be easily regenerated. This suggests that the polybenzoxazine-based NPCs are desirable for CO2 capture because of possessing a high micropore surface area, a large micropore volume, appropriate pore size distribution, and a large number of basic nitrogen functionalities.Nitrogen-rich porous carbons (NPCs) were synthesized from 1,5-dihydroxynaphthalene, urea, and formaldehyde based on benzoxazine chemistry by a soft-templating method with KOH chemical activation. They possess high surface areas of 856.8-1257.8 m2 g-1, a large pore volume of 0.15-0.65 cm3 g-1, tunable pore structure, high nitrogen content (5.21-5.32 wt%), and high char yields. The amount of the soft-templating agent F127 has multiple influences on the textural and chemical properties of the carbons, affecting the surface area and pore structure, impacting the compositions of nitrogen species and resulting in an improvement of the

  5. Solubility of small-chain carboxylic acids in supercritical carbon dioxide

    DOE PAGES

    Sparks, Darrell L.; Estevez, L. Antonio; Hernandez, Rafael; McEwen, Jason; French, Todd

    2010-07-08

    The solubility of heptanoic acid and octanoic acid in supercritical carbon dioxide has been determined at temperatures of (313.15, 323.15, and 333.15) K over a pressure range of (8.5 to 30.0) MPa, depending upon the solute. The solubility of heptanoic acid ranged from a solute concentration of (0.08 ± 0.03) kg • m-3 (T = 323.15 K, p = 8.5 MPa) to (147 ± 0.2) kg • m-3 (T = 323.15 K, p = 20.0 MPa). The lowest octanoic acid solubility obtained was a solute concentration of (0.40 ± 0.1) kg • m-3 (T = 333.15 K, p = 10.0more » MPa), while the highest solute concentration was (151 ± 2) kg • m-3 (T = 333.15 K, p = 26.7 MPa). In addition, solubility experiments were performed for nonanoic acid in supercritical carbon dioxide at 323.15 K and pressures of (10.0 to 30.0) MPa to add to the solubility data previously published by the authors. In general, carboxylic acid solubility increased with increasing solvent density. The results also showed that the solubility of the solutes decreased with increasing molar mass at constant supercritical-fluid density. Additionally, the efficacy of Chrastil's equation and other density-based models was evaluated for each fatty acid.« less

  6. Solubility of small-chain carboxylic acids in supercritical carbon dioxide

    SciTech Connect

    Sparks, Darrell L.; Estevez, L. Antonio; Hernandez, Rafael; McEwen, Jason; French, Todd

    2010-07-08

    The solubility of heptanoic acid and octanoic acid in supercritical carbon dioxide has been determined at temperatures of (313.15, 323.15, and 333.15) K over a pressure range of (8.5 to 30.0) MPa, depending upon the solute. The solubility of heptanoic acid ranged from a solute concentration of (0.08 ± 0.03) kg • m-3 (T = 323.15 K, p = 8.5 MPa) to (147 ± 0.2) kg • m-3 (T = 323.15 K, p = 20.0 MPa). The lowest octanoic acid solubility obtained was a solute concentration of (0.40 ± 0.1) kg • m-3 (T = 333.15 K, p = 10.0 MPa), while the highest solute concentration was (151 ± 2) kg • m-3 (T = 333.15 K, p = 26.7 MPa). In addition, solubility experiments were performed for nonanoic acid in supercritical carbon dioxide at 323.15 K and pressures of (10.0 to 30.0) MPa to add to the solubility data previously published by the authors. In general, carboxylic acid solubility increased with increasing solvent density. The results also showed that the solubility of the solutes decreased with increasing molar mass at constant supercritical-fluid density. Additionally, the efficacy of Chrastil's equation and other density-based models was evaluated for each fatty acid.

  7. Response of marine and freshwater algae to nitric acid and elevated carbon dioxide levels simulating environmental effects of bolide impact

    NASA Technical Reports Server (NTRS)

    Boston, P. J.

    1988-01-01

    One of the intriguing facets of the Cretaceous-Tertiary extinction is the apparently selective pattern of mortality amongst taxa. Some groups of organisms were severely affected and some remained relatively unscathed as they went through the K/T boundary. While there is argument concerning the exact interpretation of the fossil record, one of the best documented extinctions at the Cretaceous-Tertiary boundary is that of the calcareous nannoplankton. These organisms include coccolithic algae and foraminiferans. Attempts to explain their decline at the K/T boundary center around chemistry which could affect their calcium carbonate shells while leaving their silica-shelled cousins less affected or unaffected. Two environmental consequences of an extraterrestrial body impact which were suggested are the production of large quantities of nitrogen oxides generated by the shock heating of the atmosphere and the possible rise in CO2 from the dissolution of CaCO3 shells. Both of these phenomena would acidify the upper layers of the oceans and bodies of freshwater not otherwise buffered. The effects of nitric acid, carbon dioxide, or both factors on the growth and reproduction of calcareous marine coccoliths and non-calcareous marine and freshwater species of algae were considered. These experiments demonstrate that nitric acid and carbon dioxide have significant effects on important aspects of the physiology and reproduction of modern algae representative of extinct taxa thought to have suffered significant declines at the Cretaceous-Tertiary boundary. Furthermore, calcareous species showed more marked effects than siliceous species and marine species tested were more sensitive than freshwater species.

  8. Real-time measurement of nitrogen dioxide in vehicle exhaust gas by mid-infrared cavity ring-down spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Sumizawa, H.; Yamada, H.; Tonokura, K.

    2011-12-01

    The application of pulsed cavity ring-down spectroscopy (CRDS) was demonstrated for the measurement of nitrogen dioxide (NO2) in automotive exhaust gas. The transition of the ν 3 vibrational band assigned to the antisymmetric stretching mode of NO2 was probed with a thermoelectrically cooled, pulsed, mid-infrared, distributed feedback, quantum cascade laser (QCL) at 6.13 μm. The measurement of NO2 in the exhaust gas from two diesel vehicles equipped with different aftertreatment devices was demonstrated using a CRDS-based NO2 sensor, which employs a HEPA filter and a membrane gas dryer to remove interference from water as well as particulates in the exhaust gas. Stable and sensitive measurement of NO2 in the exhaust gas was achieved for more than 30 minutes with a time resolution of 1 s.

  9. Thin film transistors gas sensors based on reduced graphene oxide poly(3-hexylthiophene) bilayer film for nitrogen dioxide detection

    NASA Astrophysics Data System (ADS)

    Xie, Tao; Xie, Guangzhong; Zhou, Yong; Huang, Junlong; Wu, Mei; Jiang, Yadong; Tai, Huiling

    2014-10-01

    Reduced graphene oxide (RGO)/poly(3-hexylthiophene) (P3HT) bilayer films were firstly utilized as active layers in OTFT gas sensors for nitrogen dioxide (NO2) detection. The OTFT with RGO/P3HT bilayer film exhibited the typical transistor characteristics and better gas sensing properties at room temperature. The electrical parameters of OTFTs based on pure P3HT film and RGO/P3HT bilayer film were calculated. The threshold voltage of OTFT was positively shifted due to the high concentration carriers in RGO. The sensing properties of the sensor with RGO/P3HT bilayer film were also investigated. Moreover, the sensing mechanism was analyzed as well.

  10. Wood stove effects on indoor air quality in Brazilian homes: carcinogens, suspended particulate matter, and nitrogen dioxide analysis.

    PubMed

    Hamada, G S; Kowalski, L P; Murata, Y; Matsushita, H; Matsuki, H

    1992-10-01

    The effects of wood burning stoves on indoor air quality was investigated in a rural community of southern Brazil, during the winter season of 1991. The concentrations of polycyclic aromatic hydrocarbons (PAHs), nitrogen dioxide (NO2) and suspended particulate matter (SPM) were assessed in houses with wood stoves and the results compared with levels found in houses with gas stoves. Strikingly higher (p < 0.01) levels of PAHs, and much higher (p = 0.07) levels of SPM were found in the kitchens with wood stoves. In contrast, NO2 concentrations in the kitchen as well in personal exposure, were found to be slightly higher in houses with gas stoves. All these differences were minimally affected by smoking, outdoor air pollution or other emissions from indoor combustion products. These findings appear to support the hypothesis that domestic wood burning stoves are risk factors for some upper digestive and respiratory tract cancers in Brazil.

  11. Product analyses of ozone mediated nitration of benzimidazole derivatives with nitrogen dioxide: formation of 1-nitrobenzimidazoles and conversion to benzotriazoles.

    PubMed

    Kaiya, Toyo; Nakamura, Kei; Tanaka, Masaru; Miyata, Naoki; Kohda, Kohfuku

    2004-05-01

    Several benzimidazole derivatives having electron-withdrawing or -donating substituent(s) at the benzene moiety were used as models of the imidazole moiety of purine bases and their nitration with nitrogen dioxide and ozone (so-called Kyodai nitration) were examined. Products were extracted from the reaction mixture with AcOEt and their structures were analyzed. 1-Nitrobenzimidazole derivatives and unexpected 1-nitrobenzotriazole derivatives were identified. Although the yields of 1-nitrobenzimidazole derivatives were quite low, these were all new compounds that could be obtained only by Kyodai nitration. It was speculated that benzotriazoles were formed via 1-nitrobenzimidazoles and subsequent nitration toward benzotriazoles resulted in the formation of 1-nitrobenzotriazoles. PMID:15133210

  12. The response of ozone and nitrogen dioxide to the eruption of Mt. Pinatubo at southern and northern midlatitudes

    NASA Astrophysics Data System (ADS)

    Aquila, V.; Oman, L.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.

    2012-12-01

    Observations have shown that the global mass of nitrogen dioxide decreased at midlatitudes in both hemispheres in the year following the eruption of Mt. Pinatubo, indicating an enhanced heterogeneous chemistry due to the presence of the volcanic aerosol. In contrast, the observed ozone response at southern and northern midlatitudes was largely asymmetrical with respect to the equator, with a general decrease at northern midlatitudes and little change and even a small increase at southern midlatitudes. Simulations including enhanced heterogeneous chemistry but no other direct effects of the volcanic aerosol reproduce a decrease of ozone in both hemispheres, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and, subsequently, the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol.

  13. Measurement of nitrogen dioxide in cigarette smoke using quantum cascade tunable infrared laser differential absorption spectroscopy (TILDAS)

    NASA Astrophysics Data System (ADS)

    Shorter, Joanne H.; Nelson, David D.; Zahniser, Mark S.; Parrish, Milton E.; Crawford, Danielle R.; Gee, Diane L.

    2006-04-01

    Although nitrogen dioxide (NO 2) has been previously reported to be present in cigarette smoke, the concentration estimates were derived from kinetic calculations or from measurements of aged smoke, where NO 2 was formed some time after the puff was taken. The objective of this work was to use tunable infrared laser differential absorption spectroscopy (TILDAS) equipped with a quantum cascade (QC) laser to determine if NO 2 could be detected and quantified in a fresh puff of cigarette smoke. A temporal resolution of ˜0.16 s allowed measurements to be taken directly as the NO 2 was formed during the puff. Sidestream cigarette smoke was sampled to determine if NO 2 could be detected using TILDAS. Experiments were conducted using 2R4F Kentucky Reference cigarettes with and without a Cambridge filter pad. NO 2 was detected only in the lighting puff of whole mainstream smoke (without a Cambridge filter pad), with no NO 2 detected in the subsequent puffs. The measurement precision was ˜1.0 ppbV Hz -1/2, which allows a detection limit of ˜0.2 ng in a 35 ml puff volume. More NO 2 was generated in the lighting puff using a match or blue flame lighter (29 ± 21 ng) than when using an electric lighter (9 ± 3 ng). In the presence of a Cambridge filter pad, NO 2 was observed in the gas phase mainstream smoke for every puff (total of 200 ± 30 ng/cigarette) and is most likely due to smoke chemistry taking place on the Cambridge filter pad during the smoke collection process. Nitrogen dioxide was observed continuously in the sidestream smoke starting with the lighting puff.

  14. Measurement of nitrogen dioxide in cigarette smoke using quantum cascade tunable infrared laser differential absorption spectroscopy (TILDAS).

    PubMed

    Shorter, Joanne H; Nelson, David D; Zahniser, Mark S; Parrish, Milton E; Crawford, Danielle R; Gee, Diane L

    2006-04-01

    Although nitrogen dioxide (NO(2)) has been previously reported to be present in cigarette smoke, the concentration estimates were derived from kinetic calculations or from measurements of aged smoke, where NO(2) was formed some time after the puff was taken. The objective of this work was to use tunable infrared laser differential absorption spectroscopy (TILDAS) equipped with a quantum cascade (QC) laser to determine if NO(2) could be detected and quantified in a fresh puff of cigarette smoke. A temporal resolution of approximately 0.16s allowed measurements to be taken directly as the NO(2) was formed during the puff. Sidestream cigarette smoke was sampled to determine if NO(2) could be detected using TILDAS. Experiments were conducted using 2R4F Kentucky Reference cigarettes with and without a Cambridge filter pad. NO(2) was detected only in the lighting puff of whole mainstream smoke (without a Cambridge filter pad), with no NO(2) detected in the subsequent puffs. The measurement precision was approximately 1.0 ppbVHz(-1/2), which allows a detection limit of approximately 0.2 ng in a 35 ml puff volume. More NO(2) was generated in the lighting puff using a match or blue flame lighter (29+/-21 ng) than when using an electric lighter (9+/-3 ng). In the presence of a Cambridge filter pad, NO(2) was observed in the gas phase mainstream smoke for every puff (total of 200+/-30 ng/cigarette) and is most likely due to smoke chemistry taking place on the Cambridge filter pad during the smoke collection process. Nitrogen dioxide was observed continuously in the sidestream smoke starting with the lighting puff.

  15. Identification of novel secreted fatty acids that regulate nitrogen catabolite repression in fission yeast

    PubMed Central

    Sun, Xiaoying; Hirai, Go; Ueki, Masashi; Hirota, Hiroshi; Wang, Qianqian; Hongo, Yayoi; Nakamura, Takemichi; Hitora, Yuki; Takahashi, Hidekazu; Sodeoka, Mikiko; Osada, Hiroyuki; Hamamoto, Makiko; Yoshida, Minoru; Yashiroda, Yoko

    2016-01-01

    Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence of high-quality nitrogen sources such as NH4+ and glutamate (Glu), which is called nitrogen catabolite repression. Amino acid auxotrophic mutants of the fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing NH4Cl or Glu even when adequate amounts of required amino acids were supplied. However, growth of these mutant cells was recovered in the vicinity of colonies of the prototrophic strain, suggesting that the prototrophic cells secrete some substances that can restore uptake of amino acids by an unknown mechanism. We identified the novel fatty acids, 10(R)-acetoxy-8(Z)-octadecenoic acid and 10(R)-hydroxy-8(Z)-octadecenoic acid, as secreted active substances, referred to as Nitrogen Signaling Factors (NSFs). Synthetic NSFs were also able to shift nitrogen source utilization from high-quality to poor nitrogen sources to allow adaptive growth of the fission yeast amino acid auxotrophic mutants in the presence of high-quality nitrogen sources. Finally, we demonstrated that the Agp3 amino acid transporter was involved in the adaptive growth. The data highlight a novel intra-species communication system for adaptation to environmental nutritional conditions in fission yeast. PMID:26892493

  16. Identification of novel secreted fatty acids that regulate nitrogen catabolite repression in fission yeast.

    PubMed

    Sun, Xiaoying; Hirai, Go; Ueki, Masashi; Hirota, Hiroshi; Wang, Qianqian; Hongo, Yayoi; Nakamura, Takemichi; Hitora, Yuki; Takahashi, Hidekazu; Sodeoka, Mikiko; Osada, Hiroyuki; Hamamoto, Makiko; Yoshida, Minoru; Yashiroda, Yoko

    2016-02-19

    Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence of high-quality nitrogen sources such as NH4(+) and glutamate (Glu), which is called nitrogen catabolite repression. Amino acid auxotrophic mutants of the fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing NH4Cl or Glu even when adequate amounts of required amino acids were supplied. However, growth of these mutant cells was recovered in the vicinity of colonies of the prototrophic strain, suggesting that the prototrophic cells secrete some substances that can restore uptake of amino acids by an unknown mechanism. We identified the novel fatty acids, 10(R)-acetoxy-8(Z)-octadecenoic acid and 10(R)-hydroxy-8(Z)-octadecenoic acid, as secreted active substances, referred to as Nitrogen Signaling Factors (NSFs). Synthetic NSFs were also able to shift nitrogen source utilization from high-quality to poor nitrogen sources to allow adaptive growth of the fission yeast amino acid auxotrophic mutants in the presence of high-quality nitrogen sources. Finally, we demonstrated that the Agp3 amino acid transporter was involved in the adaptive growth. The data highlight a novel intra-species communication system for adaptation to environmental nutritional conditions in fission yeast.

  17. Effect of dietary supplementation of gallic acid on nitrogen balance, nitrogen excretion pattern and urinary nitrogenous constituents in beef cattle.

    PubMed

    Wei, Chen; Yang, Kai; Zhao, Guangyong; Lin, Shixin; Xu, Zhiwei

    2016-10-01

    The objective of the trial was to study the effects of dietary supplementation of gallic acid (GA) on nitrogen (N) balance, N excretion pattern and urinary N constituents in beef cattle. In a 4 × 4 Latin square design, four male 30-month-old Simmental cattle (443 ± 22 kg live weight) received four levels of GA (purity ≥ 98.5%), i.e. 0, 5.3, 10.5, 21.1 g/kg DM, added to a basal ration. Each experimental period lasted 17 d, consisting of 12 d adaptation and 5 d sampling. The results showed that supplementation of GA at 5.3, 10.5 or 21.1 g/kg DM did not affect the N balance but regulated the N excretion pattern by increasing the ratio of faecal N/urinary N and decreasing the ratio of urinary urea N/total urinary N in beef cattle fed at maintenance level. PMID:27494638

  18. Removal of hexenuronic acid by xylanase to reduce adsorbable organic halides formation in chlorine dioxide bleaching of bagasse pulp.

    PubMed

    Nie, Shuangxi; Wang, Shuangfei; Qin, Chengrong; Yao, Shuangquan; Ebonka, Johnbull Friday; Song, Xueping; Li, Kecheng

    2015-11-01

    Xylanase-aided chlorine dioxide bleaching of bagasse pulp was investigated. The pulp was pretreated with xylanase and followed a chlorine dioxide bleaching stage. The ATR-FTIR and XPS were employed to determine the surface chemistry of the control pulp, xylanase treated and chlorine dioxide treated pulps. The hexenuronic acid (HexA) could obviously be reduced after xylanase pretreatment, and the adsorbable organic halides (AOX) were reduced after chlorine dioxide bleaching. Compared to the control pulp, AOX could be reduced by 21.4-26.6% with xylanase treatment. Chlorine dioxide demand could be reduced by 12.5-22% to achieve the same brightness. The ATR-FTIR and XPS results showed that lignin and hemicellulose (mainly HexA) were the main source for AOX formation. Xylanase pretreatment could remove HexA and expose more lignin, which decreased the chlorine dioxide demand and thus reduced formation of AOX. PMID:26263004

  19. Oxidation of thiamine on reaction with nitrogen dioxide generated by ferric myoglobin and hemoglobin in the presence of nitrite and hydrogen peroxide.

    PubMed

    Stepuro, I I; Oparin, A Yu; Stsiapura, V I; Maskevich, S A; Titov, V Yu

    2012-01-01

    It is shown that nitrogen dioxide oxidizes thiamine to thiamine disulfide, thiochrome, and oxodihydrothiochrome (ODTch). The latter is formed during oxidation of thiochrome by nitrogen dioxide. Nitrogen dioxide was produced by incubation of nitrite with horse ferric myoglobin and human hemoglobin in the presence of hydrogen peroxide. After addition of tyrosine or phenol to aqueous solutions containing oxoferryl forms of the hemoproteins, thiamine, and nitrite, the yield of thiochrome greatly increased, whereas the yield of ODTch decreased. In the presence of high concentrations of tyrosine or phenol compounds ODTch was not formed at all. The neutral form of thiamine with the closed thiazole cycle and minor tricyclic form of thiamine do not enter the heme pocket of the protein and do not interact with the oxoferryl heme complex Fe(IV=O) or porphyrin radical. The tricyclic form of thiamine is oxidized to thiochrome by tyrosyl radicals located on the surface of the hemoprotein. The thiol form of thiamine is oxidized to thiamine disulfide by both hemoprotein tyrosyl radicals and oxoferryl heme complexes. Nitrite and also tyrosine, tyramine, and phenol readily penetrate into the heme pocket of the protein and reduce the oxyferryl complex to ferric cation. These reactions yield nitrogen dioxide as well as tyrosyl and phenoxyl radicals of tyrosine molecules and phenol compounds, respectively. Tyrosyl and phenoxyl radicals of low molecular weight compounds oxidize thiamine only to thiochrome and thiamine disulfide. The effect of oxoferryl forms of myoglobin and hemoglobin, nitrogen dioxide, and phenol on thiamine oxidative transformation as well as antioxidant properties of the hydrophobic thiamine metabolites thiochrome and ODTch are discussed.

  20. Aggregation of titanium dioxide nanoparticles: role of a fulvic acid.

    PubMed

    Domingos, Rute F; Tufenkji, Nathalie; Wilkinson, Kevin I

    2009-03-01

    The increasing use of nanomaterials in consumer products has led to increased concerns abouttheir potential environmental and health impacts. To better understand the transport, fate, and behavior of nanoparticles in aquatic systems, it is essential to understand their interactions with different components of natural waters including natural organic matter over a broad range of physicochemical conditions. Fluorescence correlation spectroscopy was used to determine the diffusion coefficients of TiO2 nanoparticles having a nominal size of 5 nm. The effects of a various concentrations of the Suwannee River Fulvic Acid (SRFA) and the roles of pH and ionic strength were evaluated. Aggregation of the bare TiO2 nanoparticles increased for pH values near the zero point of charge. At any given pH, an increase in ionic strength generally resulted in increased aggregation. Furthermore, conditions which favored adsorption of the SRFA resulted in less aggregation of the TiO2 nanoparticles, presumably due to increased steric repulsion. Under the conditions studied here, nanoparticle dispersions were often stable for environmentally relevant conditions of SRFA, pH, and ionic strength, suggesting that in the natural environment, TiO2 dispersion might occur to a greater extent than expected. PMID:19350891

  1. Characterization of narrow micropores in almond shell biochars by nitrogen, carbon dioxide, and hydrogen adsorption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Characterization of biochars usually includes surface area and pore volume determination by nitrogen adsorption. In this study, we show that there is a substantial pore volume in biochars created via slow pyrolysis from low- and high-ash almond shells that cannot be characterized in this fashion due...

  2. The spatial and seasonal variation of nitrogen dioxide and sulfur dioxide in Cape Breton Highlands National Park, Canada, and the association with lichen abundance

    NASA Astrophysics Data System (ADS)

    Gibson, Mark D.; Heal, Mathew R.; Li, Zhengyan; Kuchta, James; King, Gavin H.; Hayes, Alex; Lambert, Sheldon

    2013-01-01

    Over 200,000 tourists per year visit Cape Breton Highlands National Park, Nova Scotia, Canada. The forests within the park are home to many rare epiphytic lichens, the species diversity of which has declined in some areas. The primary motivation for this study was to gain insight into the concentrations and potential local and long-range sources of air pollution, but its association with lichen species diversity was also examined. Ogawa passive diffusion samplers were used to measure nitrogen dioxide (NO2) and sulfur dioxide (SO2) in the park at 19 sites in the winter and 20 sites in the summer of 2011. An improvement in the sensitivity of the sampler analytical protocol was developed. The mean concentrations in the park of winter and summer NO2 (0.81 and 0.16 ppb) and SO2 (0.24 and 0.21 ppb) are not at levels known to be phytotoxic to lichen. The NO2 concentrations in winter were significantly (p = 0.001) higher than those in summer whilst the SO2 concentrations did not differ significantly between winter and summer (p = 0.429). Highest NO2 concentrations in both seasons were observed in the Grand Anse Valley, presumably due to the steep road, emissions from the Pleasant Bay community at the foot of the valley and the enclosed topography of this area reducing dispersion of primary emissions. The SO2 concentrations in the park tended to be greater at elevated sites than valley sites, consistent with dispersion from long-range, rather than local, sources for this pollutant. Significant predictors in a multilinear regression for an index of air purity (lichen based measure of air quality) were lichen species number (p = 0.009), forest old growth index (p = 0.001) and distance from roads (p < 0.001) (model R2 = 0.8, model p = 0.004). The study suggests that local sources of pollution (roads emissions) are adversely associated with lichen species diversity in this National Park, compared with long-range transport, and that monitoring programs such as a lichen

  3. Carbon Monoxide, Nitric Oxide, and Nitrogen Dioxide Levels in Gas Ovens Related to Surface Pinking of Cooked Beef and Turkey.

    PubMed

    Cornforth; Rabovitser; Ahuja; Wagner; Hanson; Cummings; Chudnovsky

    1998-01-19

    Carbon monoxide (CO) and total nitrogen oxide (NO(x)()) levels were monitored during meat cookery with a standard Ovenpak and a new ultralow-NO(x)() (ULN) cyclonic gas burner. With the standard burner, CO varied from 103 to 152 ppm, NO(x)() was 1.3-10.7 ppm, and surface pinking was observed on both beef and turkey. The ULN burner at optimal efficiency produced only 6.7 ppm of CO and 1 ppm of NO(x)(), insufficient to cause surface pinking. To determine the relative contribution of CO and NO(x)() to pinking, trials were also conducted in an electric oven with various pure gases. Pinking was not observed with up to 149 ppm of CO or 5 ppm of NO. However, as little as 0.4 ppm of nitrogen dioxide (NO(2)) caused pinking of turkey rolls. Beef roasts were pink at >2.5 ppm of NO(2). Thus, pinking previously attributed to CO and NO in gas ovens is instead due to NO(2), which has much greater reactivity than NO with moisture at meat surfaces. PMID:10554228

  4. Methanol Droplet Extinction in Oxygen/Carbon-dioxide/Nitrogen Mixtures in Microgravity: Results from the International Space Station Experiments

    NASA Technical Reports Server (NTRS)

    Nayagam, Vedha; Dietrich, Daniel L.; Ferkul, Paul V.; Hicks, Michael C.; Williams, Forman A.

    2012-01-01

    Motivated by the need to understand the flammability limits of condensed-phase fuels in microgravity, isolated single droplet combustion experiments were carried out in the Combustion Integrated Rack Facility onboard the International Space Station. Experimental observations of methanol droplet combustion and extinction in oxygen/carbon-dioxide/nitrogen mixtures at 0.7 and 1 atmospheric pressure in quiescent microgravity environment are reported for initial droplet diameters varying between 2 mm to 4 mm in this study.The ambient oxygen concentration was systematically lowered from test to test so as to approach the limiting oxygen index (LOI) at fixed ambient pressure. At one atmosphere pressure, ignition and some burning were observed for an oxygen concentration of 13% with the rest being nitrogen. In addition, measured droplet burning rates, flame stand-off ratios, and extinction diameters are presented for varying concentrations of oxygen and diluents. Simplified theoretical models are presented to explain the observed variations in extinction diameter and flame stand-off ratios.

  5. Phosphorus constrains accelerated nitrogen cycling in limed acidic forests

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Shaw, A. N.; Kluber, L. A.; Burke, D. J.; Carrino-Kyker, S. R.; Smemo, K. A.

    2011-12-01

    Anthropogenic deposition can increase phosphorus (P) limitation by abiotic and biotic means. Soil acidification can remove P from available pools and nitrogen (N) deposition can increase the demand for P. We reason that chronic acidic deposition is promoting P limitation in acidic hardwood forests and thereby altering N cycling. The objectives of this study were to investigate the interactive influence of P availability and soil pH on N and P cycling and availability to determine if the response varies between two physiographic regions experiencing similar chronic acidic deposition. We addressed these objectives by experimentally manipulating soil pH, P, or both in strongly acidic glaciated and unglaciated hardwood forests in eastern Ohio, USA. Our results suggest complex interactions between P, soil pH, and the N cycle. Glaciated soils were found to be more N-saturated with nitrification rates 18 times greater than in unglaciated soils. Elevating pH, with or without added P, doubled nitrification rates in glaciated soils. For unglaciated soils, raising pH increased nitrification 10-fold, but increased nitrification only 5-fold in combination with P. This result suggests raising soil pH lowered the demand of soil N, or directly stimulated nitrifying activity, and that increasing P availability could limit N availability. To various degrees, readily available P was geochemically or biologically immobilized in all treatments, suggesting chronic P deficiency in these ecosystems. Phosphorus immobilization decreased as soil pH was elevated, but elevated P either had no effect (glaciated) or doubled P immobilization rates (unglaciated). These results suggest that raising soil pH reduces microbial P limitation for phosphate, whereas adding P appears to make phosphate scarcer. We suggest that P plays an important role in N transformations and cycling, but appears more important in unglaciated soils than in glaciated soils. Chronic soil acidification may have a greater

  6. Simultaneous inhibition of carbon and nitrogen mineralization in a forest soil by simulated acid precipitation

    SciTech Connect

    Klein, T.M.; Novick, N.J.; Kreitinger, J.P.; Alexander, M.

    1984-06-01

    One method to simulate the long-term exposure of soil to acid rain involves the addition of single doses of concentrated acid. The inhibition of carbon mineralization accompanied by a stimulation of nitrogen mineralization may result from this severe, unnatural treatment. The present study was designed to determine whether the inhibition of carbon mineralization and the accompanying enhanced nitrogen mineralization would occur when soils are treated with more dilute acid for long periods of time, as takes place in nature.

  7. Sequential multiple analyses of atmospheric nitrous acid and nitrogen oxides.

    PubMed

    Toda, Kei; Hato, Yuki; Mori, Kotaro; Ohira, Shin-Ichi; Namihira, Takao

    2007-03-15

    Sequential injection analysis (SIA) was applied to multi-gas monitoring for atmospheric analysis. HONO, NO(2) or NO was collected in an individual diffusion scrubber in which the channel array was filled with either HCl or triethanolamine solution. All analytes were collected in the form of nitrite ions in the scrubber, and were transferred via a 12-port selection valve into a 2.5-ml syringe. The reagent, 3-amino-1,5-naphthalenedisulfonic acid (C-acid) solution was subsequently introduced into the syringe, and inter-mixed with the nitrite sample, whereafter the mixed solution was transferred to a heated reactor and held for 3min at 100 degrees C. After that, the sample/reagent solution was returned to the syringe and alkalinized. Then, the final solution was analyzed using a homemade fluorescence detector. Atmospheric HONO, NO(2) and NO were successfully monitored 3 or 4times/h. The limits of detection were 0.22, 0.28 and 0.35ppbv for HONO, NO(2) and NO, respectively. It was demonstrated for the first time that SIA is a good tool for multi-gas atmospheric analysis. These nitrogen-oxygen compounds are interconvertible, and the simultaneous measurement of these gases is important. Especially, HONO is a source of OH radicals which contribute greatly to atmospheric pollution, and indeed atmospheric chemistry. This method allows the three gases to be measured using one system. The NO(2) and NO data obtained by SIA was compared with those obtained using chemiluminescence instrument. SIA has been successfully applied to atmospheric measurements. Interestingly, it was observed that HONO levels rose toward the end of periods of rain.

  8. Solubility of carbon dioxide in acetone and propionic acid at temperatures between 298 K and 333 K

    SciTech Connect

    Adrian, T.; Maurer, G.

    1997-07-01

    The solubility of carbon dioxide in organic solvents acetone and propionic acid has been measured with an analytical method. The composition and the density of the liquid phase in the binary vapor-liquid equilibrium have been investigated at (313 and 333) K (for the system carbon dioxide + acetone) and at (298, 313, and 333) K (for the system carbon dioxide + propionic acid) at pressures up the binary critical pressure. The experimental results for the phase equilibrium have been correlated with the Peng-Robinson EOS applying several mixing rules.

  9. Electrodeposited nanostructured lead dioxide as a thin film electrode for a lightweight lead-acid battery

    NASA Astrophysics Data System (ADS)

    Egan, D. R. P.; Low, C. T. J.; Walsh, F. C.

    Thin films of nanostructured lead dioxide are investigated as a positive electrode material for a lightweight lead-acid battery. The films are obtained by constant current deposition from electrolytes of lead methanesulfonate in methanesulfonic acid. The films are tested in two conditions namely (a) cyclic voltammetry and (b) constant current battery cycling in sulfuric acid. The charge and discharge current density, charge density and charge efficiency are measured as a function of cycle number. The effect of deposition conditions, such as solution temperature (295 and 333 K), type of substrate and electrolyte additive (hexadecyltrimethylammonium hydroxide), on the electrochemical performance of the PbO 2 in sulfuric acid is investigated. It is found that the as-deposited lead dioxide film is compact and nanostructured β-phase structure. Following successive cycling in sulfuric acid, the compact thin film gradually transforms into a porous microstructure consisting of positive active material (PbO 2 and PbSO 4), several tens of nanometres size. The charge density, discharge density and peak discharge current density of the PbO 2 improve with cycling of the thin film electrode.

  10. Carbonic acid as a reserve of carbon dioxide on icy moons: The formation of carbon dioxide (CO{sub 2}) in a polar environment

    SciTech Connect

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-06-20

    Carbon dioxide (CO{sub 2}) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ν{sub 3} band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO{sub 2} band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H{sub 2}O)-carbon dioxide (CO{sub 2}) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ν{sub 3} band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

  11. Airborne Measurements of Nitric Oxide, Nitrogen Dioxide, Ozone, and Total Reactive Nitrogen During the NASA Global Tropospheric Experiment

    NASA Technical Reports Server (NTRS)

    Carroll, Mary Anne

    2000-01-01

    Fabrication of the University of Michigan Multichannel Chemiluminescence Instrument (UMMCI) was completed in early 1996 and the instrument participated in test flights on the NASA P3B at Wallops Island prior to integration and deployment for the PEM- Tropics A Mission. The UMMCI consists of 4 channels for simultaneous measurements of ozone and NO with the option for measurements of NO2 and NOy (total reactive nitrogen) when converters are placed upstream of the NO channels. Each NO channel consists of a zeroing volume and reaction vessel, while the ozone channel consists of an ozone catalyst (or scrubber) trap that is not in line with the reaction vessel. The detectors in all for channels are Hamamatsu photomultiplier tubes, which are followed by pulse amplifier discriminators on the NO channels and an electrometer on the ozone channel. Schematics of the Detector Module and NOx/03 Probe Insert and Diagrams of the Control and Data System, the Power and Ground System, the Gas Flow System, and the Calibration System Flow are attached. Intercomparisons were conducted with G. Gregory, NASA/Langley, during the test flights (following prior calibration of the ozone generator/calibrators at the Wallops Long-Path Absorption facility). Initial test results appeared to be reasonable, and instrument characterization studies proceeded for the ozone channel and the 3 NO channels until deployment for integration for the PEM-Tropics Mission. Ozone data was obtained for Flights #4, and 6-2 1, and finalized data was submitted to the PEM-Tropics Data Archive and to the Science Team during the April 1997 Data Workshop. Although it initially appeared that the instrument sensitivity varied, subsequent tests showed that this was the fault of a leak in the ozone calibrator. In fact; the instrument sensitivity has not been observed to vary in a large number of tests over the years since the PEM-Tropics mission. We have, therefore, a very high degree of confidence in the O3 data that we

  12. Photocatalytic equipment with nitrogen-doped titanium dioxide for air cleaning and disinfecting

    NASA Astrophysics Data System (ADS)

    Son Le, Thanh; Buu Ngo, Quoc; Dung Nguyen, Viet; Chau Nguyen, Hoai; Hien Dao, Trong; Tin Tran, Xuan; Kabachkov, E. N.; Balikhin, I. L.

    2014-03-01

    Nitrogen-doped TiO2 nanoparticle photocatalysts were synthesized by a sol-gel procedure using tetra-n-butyl orthotitanate as a titanium precursor and urea as a nitrogen source. Systematic studies for the preparation parameters and their impact on the material's structure were carried out by multiple techniques: thermogravimetric and differential scanning calorimetric analysis, x-ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive x-ray spectroscopy and UV-Vis diffuse reflectance spectrophotometry showed that the nitrogen-doped TiO2 calcined at 500 °C for 3 h exhibited a spherical form with a particle size about 15-20 nm and crystal phase presented a mixture of 89.12% anatase. The obtained product was deposited on a porous quartz tube (D = 74 mm l = 418 mm) to manufacture an air photocatalytic cleaner as a prototype of the TIOKRAFT company's equipment. The created air cleaner was able to remove 60% of 10 ppm acetone within 390 min and degrade 98.5% of bacteria (total aerobic bacteria and fungi, 300 cfu m-3) within 120 min in a 10 m3 box. These photodegradation activities of N-TiO2 are higher than that of the commercial nano-TiO2 (Skyspring Inc., USA, particle size of 5-10 nm).

  13. Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on San Juan Basin Coal

    SciTech Connect

    K. A. M. Gasem; R. L. Robinson; S. R. Reeves

    2002-03-01

    The major objectives of this project were to (a) measure the adsorption behavior of pure methane, nitrogen, CO{sub 2} and their binary and ternary mixtures on wet Tiffany coal at 130 F and pressures to 2000 psia; (b) correlate the equilibrium adsorption isotherm data using the extended Langmuir model, the Langmuir model, the loading ratio correlation and the Zhou-Gasem-Robinson equation of state; and (c) establish sorption-time estimates for the pure components. Specific accomplishments are summarized below regarding the complementary tasks involving experimental work and data correlation. Representative coal samples from BP Amoco Tiffany Injection Wells No.1 and No.10 were prepared, as requested. The equilibrium moisture content and particle size distribution of each coal sample were determined. Compositional coal analyses for both samples were performed by Huffman Laboratories, Inc. Pure gas adsorption for methane on wet Tiffany coal samples from Injection Wells No.1 and No.10 was measured separately at 130 F (327.6 K) and pressures to 2000 psia (13.7 MPa). The average expected uncertainty in these data is about 3% (9 SCF/ton). Our measurements indicate that the adsorption isotherms of the two coal samples exhibit similar Langmuir-type behavior. For the samples from the two wells, a maximum variation of about 5% in the amount adsorbed is observed at 2000 psia. Gas adsorption isotherms were measured for pure methane, nitrogen and CO{sub 2} on a wet, mixed Tiffany coal sample. The coal sample was an equal-mass mixture of coals from Well No.1 and Well No.10. The adsorption measurements were conducted at 130 F at pressures to 2000 psia. The adsorption isotherms have average expected experimental uncertainties of 3% (9 SCF/ton), 6% (8 SCF/ton), and 7% (62 SCF/ton) for methane, nitrogen, and CO{sub 2}, respectively. Adsorption isotherms were measured for methane/nitrogen, methane/CO{sub 2} and nitrogen/CO{sub 2} binary mixtures on wet, mixed Tiffany coal at 130 F and

  14. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  15. Effects of inhaled acids on lung biochemistry

    SciTech Connect

    Last, J.A.

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  16. Effects of inhaled acids on lung biochemistry.

    PubMed

    Last, J A

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  17. Manganese dioxide graphite composite electrodes: application to the electroanalysis of hydrogen peroxide, ascorbic acid and nitrite.

    PubMed

    Langley, Cathryn E; Sljukić, Biljana; Banks, Craig E; Compton, Richard G

    2007-02-01

    The modification of carbon powder with manganese dioxide using a wet impregnation procedure with electrochemical characterisation of the modified powder is described. The process involves saturation of the carbon powder with manganese(II) nitrate followed by thermal treatment at ca. 773 K leading to formation of manganese(IV) oxide on the surface of the carbon powder. The construction of composite electrodes based on manganese dioxide modified carbon powder and epoxy resin is also described, including optimisation of the percentage of the modified carbon powder. Composite electrodes showed attractive performances for electroanalytical applications, proving to be suitable for the electrochemical detection of hydrogen peroxide, ascorbic acid and nitrite ions with limits of detection comparable to the detection limits achieved by other analytical techniques. The results obtained for detection of these analytes, together with composite electrodes flexible design and low cost offers potential application of composite electrodes in biosensors.

  18. Galvanic interaction between chalcopyrite and manganese dioxide in sulfuric acid medium

    NASA Astrophysics Data System (ADS)

    Gantayat, B. P.; Rath, P. C.; Paramguru, R. K.; Rao, S. B.

    2000-02-01

    Dissolution of chalcopyrite and managanese dioxide minerals in the presence of each other in sulfuric acid medium was studied using compact disc electrodes of the minerals under various H2SO4 concentrations (0.05 to 0.5 M). [H+] had a positive effect on the reaction rate. Strong galvanic interaction was observed to take place between chalcopyrite and manganese dioxide, the galvanic interaction predominating over the individual dissolution (self-corrosion) rates. Evans diagrams constructed from polarization curves of the two minerals were helpful in interpreting the leaching data. The electrochemical nature of the dissolution reaction was analyzed through application of the Butler-Volmer equation and was confirmed from polarization measurements conducted with the respective mineral electrodes.

  19. Nitrogenous compounds stimulate glucose-derived acid production by oral Streptococcus and Actinomyces.

    PubMed

    Norimatsu, Yuka; Kawashima, Junko; Takano-Yamamoto, Teruko; Takahashi, Nobuhiro

    2015-09-01

    Both Streptococcus and Actinomyces can produce acids from dietary sugars and are frequently found in caries lesions. In the oral cavity, nitrogenous compounds, such as peptides and amino acids, are provided continuously by saliva and crevicular gingival fluid. Given that these bacteria can also utilize nitrogen compounds for their growth, it was hypothesized that nitrogenous compounds may influence their acid production; however, no previous studies have examined this topic. Therefore, the present study aimed to assess the effects of nitrogenous compounds (tryptone and glutamate) on glucose-derived acid production by Streptococcus and Actinomyces. Acid production was evaluated using a pH-stat method under anaerobic conditions, whereas the amounts of metabolic end-products were quantified using high performance liquid chromatography. Tryptone enhanced glucose-derived acid production by up to 2.68-fold, whereas glutamate enhanced Streptococcus species only. However, neither tryptone nor glutamate altered the end-product profiles, indicating that the nitrogenous compounds stimulate the whole metabolic pathways involving in acid production from glucose, but are not actively metabolized, nor do they alter metabolic pathways. These results suggest that nitrogenous compounds in the oral cavity promote acid production by Streptococcus and Actinomyces in vivo.

  20. Live fire support services: Expansion of n-gas model to include nitrogen dioxide effects in the rat. Final report, 15 November 1993-31 December 1994

    SciTech Connect

    1994-12-31

    The N-gas model is an empirical tool developed by the fire science community to predict toxic potency of various materials when burned based on the chemical nature of gases produced. This research is extending applicability of the N-gas equation to military scenarios by expanding the empirical formula to include the effects of exposure to NO2 (in rodents). Rats are exposed, nose-only and under controlled conditions, to nitrogen dioxide singly and in combination with carbon monoxide, carbon dioxide, and air. LC5O values are determined based on 30 minute exposure, followed by 2 week post exposure. Blood gas, hemoglobin and respiratory data are collected.

  1. Formation of nitrate and ammonium ions in titanium dioxide mediated photocatalytic degradation of organic compounds containing nitrogen atoms

    SciTech Connect

    Low, G.K.-C.; McEvoy, S.R.; Matthews, R.W. )

    1991-03-01

    The photocatalytic oxidation of a related series of primary, secondary, and tertiary amines and other nitrogen- and sulfur-containing organic compounds over a UV-illuminated film of TiO{sub 2} has been studied. The compounds were as follows: n-pentylamine, piperidine, pyridine, phenylalanine, desipramine, thioridazine, penicillamine, isosorbide dinitrate, 4-nitrocatechol, 2,4-dinitrophenol, cyclophosphamide, 5-fluorouracil, atrazine, ethylenediaminetetracetic acid, and tetrabutylammonium phosphate. Both ammonium and nitrate ions were formed. The relative concentration of the two ions depended on the nature of the nitrogen in a compound, but was also influenced by the illumination time and concentration of the solute. It was found that for n-pentylamine, piperidine and pyridine, the rate of formation of ammonium ions was n-pentylamine {much gt} pyridine > piperidine. The order of rates of nitrate formation was pyridine = piperidine {much gt} pentylamine. For n-pentylamine the rate of formation of ammonium ions was {approximately}100 times that of nitrate.

  2. Regulation of Senescence in Carnation (Dianthus caryophyllus): Effect of Abscisic Acid and Carbon Dioxide on Ethylene Production.

    PubMed

    Mayak, S; Dilley, D R

    1976-11-01

    Abscisic acid hastened senescence of carnation flowers and this was preceded by stimulation of accelerated ethylene production. Carbon dioxide delayed the onset of autocatalytic ethylene production in flowers regardless of treatment with abscisic acid. Flowers exhibited a low and transient climacteric of ethylene production without wilting while in 4% carbon dioxide and underwent accelerated ethylene production culminating in wilting when removed from carbon dioxide. Hypobaric ventilation, which lowers ethylene to hyponormal levels within tissues, extended flower longevity and largely negated enhancement of senescence by abscisic acid. Supplementing hypobarically ventilated flowers with ethylene hastened senescence irrespective of abscisic acid treatment. Collectively, the data indicate that abscisic acid hastens senescence of carnations largely as a result of advancing the onset of autocatalytic ethylene production.

  3. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

    NASA Astrophysics Data System (ADS)

    Gomez, Virginia; Bear, Joseph C.; McNaughter, Paul D.; McGettrick, James D.; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R.; Dunnill, Charles W.

    2015-10-01

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co

  4. Responses of sugar maple and hemlock seedlings to elevated carbon dioxide under altered above- and belowground nitrogen sources.

    PubMed

    Eller, Allyson S D; McGuire, Krista L; Sparks, Jed P

    2011-04-01

    Various human-induced changes to the atmosphere have caused carbon dioxide (CO₂), nitrogen dioxide (NO₂) and nitrate deposition (NO₃⁻) to increase in many regions of the world. The goal of this study was to examine the simultaneous influence of these three factors on tree seedlings. We used open-top chambers to fumigate sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) with ambient or elevated CO₂ and NO₂ (elevated concentrations were 760 ppm and 40 ppb, respectively). In addition, we applied an artificial wet deposition of 30 kg ha⁻¹ year⁻¹ NO₃⁻ to half of the open-top chambers. After two growing seasons, hemlocks showed a stimulation of growth under elevated CO₂, but the addition of elevated NO₂ or NO₃⁻ eliminated this effect. In contrast, sugar maple seedlings showed no growth enhancement under elevated CO₂ alone and decreased growth in the presence of NO₂ or NO₃⁻, and the combined treatments of elevated CO₂ with increased NO₂ or NO₃⁻ were similar to control plants. Elevated CO₂ induced changes in the leaf characteristics of both species, including decreased specific leaf area, decreased %N and increased C:N. The effects of elevated CO₂, NO₂ and NO₃⁻ on growth were not additive and treatments that singly had no effect often modified the effects of other treatments. The growth of both maple and hemlock seedlings under the full combination of treatments (CO₂ + NO₂ + NO₃⁻) was similar to that of seedlings grown under control conditions, suggesting that models predicting increased seedling growth under future atmospheric conditions may be overestimating the growth and carbon storage potential of young trees.

  5. Preparation of porous nitrogen-doped titanium dioxide microspheres and a study of their photocatalytic, antibacterial and electrochemical activities

    SciTech Connect

    Chen, S.; Chu, W.; Huang, Y.Y.; Liu, X.; Tong, D.G.

    2012-12-15

    Graphical abstract: Porous N-doped TiO{sub 2} microspheres were prepared for the first time via plasma technique. The sample exhibited better photocatalytic activity, photoinduced inactivation activity and better electrochemical activity than those of TiO{sub 2} microspheres and P25. Display Omitted Highlights: ► Porous N-doped TiO{sub 2} microspheres were prepared via nitrogen plasma technique. ► Plasma treatment did not affect the porous structure of the TiO{sub 2} microspheres. ► With the plasma treatment, the N contents in the samples increased. ► Their photocatalytic, antibacterial and electrochemical activities were studied. -- Abstract: Nitrogen-doped titanium dioxide (N-doped TiO{sub 2}) microspheres with porous structure were prepared via the nitrogen-assisted glow discharge plasma technique at room temperature for the first time. The samples were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption–desorption measurement, UV–Vis diffuse reflectance spectra, photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the plasma treatment did not affect the porous structure of the TiO{sub 2} microspheres. With the plasma treatment, the N contents in the samples increased. During the photocatalytic degradation of methylene blue under simulative sunlight irradiation, the sample after plasma treatment for 60 min (N-TiO{sub 2}-60) exhibited higher photocatalytic activity than those of the TiO{sub 2} microspheres, P25 and other N-doped TiO{sub 2} microspheres. Furthermore, the N-TiO{sub 2}-60 showed excellent antibacterial activities towards Escherichia coli under visible irradiation. These should be attributed to the enhancement of the visible light region absorption for TiO{sub 2} after N-doping. Electrochemical data demonstrated that the N-doping not only enhanced the electrochemical activity of TiO{sub 2}, but also improved the reversibility of Li insertion/extraction reactions

  6. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis.

    PubMed

    Gomez, Virginia; Bear, Joseph C; McNaughter, Paul D; McGettrick, James D; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R; Dunnill, Charles W

    2015-11-14

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with "Janus-like" characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.

  7. Photochemical synthesis of citric acid cycle intermediates based on titanium dioxide.

    PubMed

    Saladino, Raffaele; Brucato, John Robert; De Sio, Antonio; Botta, Giorgia; Pace, Emanuele; Gambicorti, Lisa

    2011-10-01

    The emergence of the citric acid cycle is one of the most remarkable occurrences with regard to understanding the origin and evolution of metabolic pathways. Although the chemical steps of the cycle are preserved intact throughout nature, diverse organisms make wide use of its chemistry, and in some cases organisms use only a selected portion of the cycle. However, the origins of this cycle would have arisen in the more primitive anaerobic organism or even back in the proto-metabolism, which likely arose spontaneously under favorable prebiotic chemical conditions. In this context, we report that UV irradiation of formamide in the presence of titanium dioxide afforded 6 of the 11 carboxylic acid intermediates of the reductive version of the citric acid cycle. Since this cycle is the central metabolic pathway of contemporary biology, this report highlights the role of photochemical processes in the origin of the metabolic apparatus.

  8. Efficiency of a Photoreactor Packed with Immobilized Titanium Dioxide Nanoparticles in the Removal of Acid Orange 7.

    PubMed

    Sheidaei, Behnaz; Behnajady, Mohammad A

    2016-05-01

    In this paper, the removal efficiency of Color Index Acid Orange 7 (AO7) as a model contaminant was investigated in a batch-recirculated photoreactor packed with immobilized titanium dioxide type P25 nanoparticles on glass beads. The effects of different operational parameters such as the initial concentration of AO7, the volume of solution, the volumetric flowrate, and the light source power in the photoreactor were investigated. The results indicate that the removal percent increased with the rise in volumetric flowrate and power of the light source, but decreased with the rise of the initial concentration of AO7 and the volume of solution. The AO7 degradation was followed through total organic carbon, gas chromatography/mass spectroscopy (GC/MS), and mineralization products analysis. The ammonium and sulfate ions were analyzed as mineralization products of nitrogen and sulfur heteroatoms, respectively. The results of GC/MS revealed the production of 1-indanone, 1-phthalanone, and 2-naphthalenol as intermediate products for the removal of AO7 in this process.

  9. Efficiency of a Photoreactor Packed with Immobilized Titanium Dioxide Nanoparticles in the Removal of Acid Orange 7.

    PubMed

    Sheidaei, Behnaz; Behnajady, Mohammad A

    2016-05-01

    In this paper, the removal efficiency of Color Index Acid Orange 7 (AO7) as a model contaminant was investigated in a batch-recirculated photoreactor packed with immobilized titanium dioxide type P25 nanoparticles on glass beads. The effects of different operational parameters such as the initial concentration of AO7, the volume of solution, the volumetric flowrate, and the light source power in the photoreactor were investigated. The results indicate that the removal percent increased with the rise in volumetric flowrate and power of the light source, but decreased with the rise of the initial concentration of AO7 and the volume of solution. The AO7 degradation was followed through total organic carbon, gas chromatography/mass spectroscopy (GC/MS), and mineralization products analysis. The ammonium and sulfate ions were analyzed as mineralization products of nitrogen and sulfur heteroatoms, respectively. The results of GC/MS revealed the production of 1-indanone, 1-phthalanone, and 2-naphthalenol as intermediate products for the removal of AO7 in this process. PMID:27131308

  10. Nitrogen

    USGS Publications Warehouse

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  11. Experimental study on the nitrogen dioxide and particulate matter emissions from diesel engine retrofitted with particulate oxidation catalyst.

    PubMed

    Feng, Xiangyu; Ge, Yunshan; Ma, Chaochen; Tan, Jianwei; Yu, Linxiao; Li, Jiaqiang; Wang, Xin

    2014-02-15

    A particulate oxidation catalyst (POC) was employed to perform experiments on the engine test bench to evaluate the effects on the nitrogen dioxide (NO2) and particulate matter (PM) emissions from diesel engine. The engine exhaust was sampled from both upstream and downstream of the POC. The results showed that the POC increased the ratios of NO2/NOx significantly in the middle and high loads, the ratio of NO2/nitrogen oxides (NOx) increased 4.5 times on average under all experiment modes with the POC. An engine exhaust particle sizer (EEPS) was used to study the particle number-weighted size distributions and the abnormal particle emissions with the POC. The results indicated that the average reduction rate of particle number (PN) was 61% in the operating range of the diesel engine. At the engine speed of 1,400 r/min, the reduction rates of PN tended to decrease with the larger particle size. In the long time run under the steady mode (520 Nm, 1,200 r/min), abnormal particle emissions after the POC happened seven times in the first hour, and the average PN concentration of these abnormal emission peaks was much higher than that in normal state. The particle emissions of peaks 1-5 equaled the particles emitted downstream of the POC in normal state for 1.9h in number concentration, and for 3.6h in mass concentration. The PN concentrations tended to increase over time in 5h under the steady engine mode and the increase of the PN in the size range of 6.04-14.3 nm was more evident.

  12. Evaluating the uncertainties of thermal catalytic conversion in measuring atmospheric nitrogen dioxide at four differently polluted sites in China

    NASA Astrophysics Data System (ADS)

    Xu, Zheng; Wang, Tao; Xue, L. K.; Louie, Peter K. K.; Luk, Connie W. Y.; Gao, J.; Wang, S. L.; Chai, F. H.; Wang, W. X.

    2013-09-01

    A widely used method for measuring nitrogen dioxide (NO2) in the atmosphere is the conversion of NO2 to nitric oxide (NO) on the hot surface of a molybdenum oxide (MoO) catalyst followed by the chemiluminescence detection of NO. Although it has long been recognized that this type of conversion may suffer from the positive interference of other oxidized nitrogen compounds, evaluations of such interference in the atmosphere are scarce, thus rendering it difficult to make use of a large portion of the NO2 or NOx data obtained via this method (often denoted as NO2* or NOx*). In the present study, we compared the MoO converter with a selective, more accurate photolytic approach at four differently polluted sites in China. The converter worked well at the urban site, which was greatly affected by fresh emissions, but, on average, overestimated NO2 by 30%-50% at the two suburban sites and by more than 130% at the mountain-top site during afternoon hours, with a much larger positive bias seen during the top 10% of ozone events. The degree of overestimation depended on both air-parcel age and the composition of the oxidation products/intermediates of NOx (NOz). We attempted to derive an empirical formula to correct for this overestimation using concurrently measured O3, NO, and NO2* at the two suburban sites. Although the formula worked well at each individual site, the different NOz partitions at the sites made it difficult to obtain a universal formula. In view of the difficulty of assessing the uncertainties of the conventional conversion method, thus limiting the usability of data obtained via this method in atmospheric research, we suggest that, in areas away from fresh NOx emission sources, either a more selective NO2 measurement method or a NOy (NOx and its reaction products and intermediates) instrument should be adopted.

  13. Carbon dioxide enrichment: Data on the response of cotton to varying CO{sub 2}, irrigation, and nitrogen

    SciTech Connect

    Sepanski, R.J.; Kimball, B.A.; Mauney, J.R.; La Morte, R.L.; Guinn, G.; Nakayama, F.S.; Radin, J.W.; Mitchell, S.T.; Parker, L.L.; Peresta, G.J.; Nixon, P.E. III; Savoy, B.; Harris, S.M.; MacDonald, R.; Pros, H.; Martinez, J.; Lakatos, E.A.

    1992-06-01

    This document presents results from field CO{sub 2}-enrichment experiments conducted over five consecutive growing seasons, 1983--1987. These results comprise data concerning the effects of continuous CO{sub 2} enrichment on the growth of cotton under optimal and limiting levels of water and nitrogen. Unlike many prior C0{sub 2} enrichment experiments in growth chambers or greenhouses, these studies were conducted on field-planted cotton at close to natural conditions using the open-top chamber approach. Measurements were made on a variety of crop response variables at intervals during the growing season and upon crop harvest. The initial experiment examined the effects of varying C0{sub 2} concentration only. In the following two seasons, the interactive effects of C0{sub 2} concentration and water availability were studied. In the final two seasons, the effects of the three-way interaction between C0{sub 2} concentration, water availability, and nitrogen fertility were investigated. The data comprise three types of information: identification variables (such as year, institution and situ codes, and treatment regimens), intermediate growth measurements (such as plant height, leaf area index, number of flowers, and dry weight of leaves) taken at various times during the growing season, and crop harvest results (such as lint yield, seed yield, and total aboveground dry biomass). They are available free of charge as a numeric data package (NAP) from the Carbon Dioxide Information Analysis Center. The NAP consists of this document and a magnetic tape (or a floppy diskette, upon request) containing machine-readable files. This document provides sample listings of the CO{sub 2} enrichment response data as they appear on the magnetic tape or floppy diskette and provides detailed descriptions of the design and methodology of these experiments, as well as a complete hard copy listing of all of the data in the form of a supplemental text provided as an appendix.

  14. Carbon dioxide enrichment: Data on the response of cotton to varying CO sub 2 , irrigation, and nitrogen

    SciTech Connect

    Sepanski, R.J. . Energy, Environment and Resources Center); Kimball, B.A.; Mauney, J.R.; La Morte, R.L.; Guinn, G.; Nakayama, F.S.; Radin, J.W.; Mitchell, S.T.; Parker, L.L.; Peresta, G.J.; Nixon, P.E. III; Savoy, B.; Harris, S.M.; MacDonald, R.; Pros, H.; Martinez, J. ); Lakatos, E.A. (Arizona Univ., Tucs

    1992-06-01

    This document presents results from field CO{sub 2}-enrichment experiments conducted over five consecutive growing seasons, 1983--1987. These results comprise data concerning the effects of continuous CO{sub 2} enrichment on the growth of cotton under optimal and limiting levels of water and nitrogen. Unlike many prior C0{sub 2} enrichment experiments in growth chambers or greenhouses, these studies were conducted on field-planted cotton at close to natural conditions using the open-top chamber approach. Measurements were made on a variety of crop response variables at intervals during the growing season and upon crop harvest. The initial experiment examined the effects of varying C0{sub 2} concentration only. In the following two seasons, the interactive effects of C0{sub 2} concentration and water availability were studied. In the final two seasons, the effects of the three-way interaction between C0{sub 2} concentration, water availability, and nitrogen fertility were investigated. The data comprise three types of information: identification variables (such as year, institution and situ codes, and treatment regimens), intermediate growth measurements (such as plant height, leaf area index, number of flowers, and dry weight of leaves) taken at various times during the growing season, and crop harvest results (such as lint yield, seed yield, and total aboveground dry biomass). They are available free of charge as a numeric data package (NAP) from the Carbon Dioxide Information Analysis Center. The NAP consists of this document and a magnetic tape (or a floppy diskette, upon request) containing machine-readable files. This document provides sample listings of the CO{sub 2} enrichment response data as they appear on the magnetic tape or floppy diskette and provides detailed descriptions of the design and methodology of these experiments, as well as a complete hard copy listing of all of the data in the form of a supplemental text provided as an appendix.

  15. Reaction of chlorine dioxide with amino acids and peptides: kinetics and mutagenicity studies.

    PubMed

    Tan, H K; Wheeler, W B; Wei, C I

    1987-08-01

    Chlorine dioxide (ClO2) is currently being considered as an alternate to chlorine as a disinfectant for water treatment. Many organic compounds present in water and food treated with ClO2 are subject to oxidation. 21 amino acids and 3 peptides (L-aspartyl-L-phenylalanine methyl ester (aspartame), L-glycyl-L-tryptophan and L-tryptophylglycine) were studied for their reactivity with ClO2. Chlorine dioxide reacted only with 6 amino acids in 0.1 M sodium phosphate buffer, pH 6.0. The reaction with cysteine, tryptophan and tyrosine was too rapid to be monitored either iodometrically or spectrophotometrically. The reaction with histidine, hydroxyproline and proline was found to be pseudo-first order. ClO2 readily reacted with L-glycyl-L-tryptophan and L-tryptophylglycine but not with aspartame. Mutagenicity studies with the Salmonella microsome assay of the reaction mixtures of ClO2 with those 6 reactive amino acids and the 3 peptides indicated that the reaction products of the 3 peptides, hydroxyproline, and tyrosine exerted mutagenic activity toward both tester strains of TA98 and TA100 in the presence and absence of rat-liver S9 mix.

  16. The photosynthesis - leaf nitrogen relationship at ambient and elevated atmospheric carbon dioxide: a meta-analysis

    SciTech Connect

    Andrew G. Peterson; J. Timothy Ball; Yiqi Luo; Christopher B. Field; Peter B. Reich; Peter S. Curtis; Kevin L. Griffin; Carla S Gunderson; Richard J. Norby; David T. Tissue; Manfred Forstreuter; Ana Rey; Christoph S. Vogel; CMEAL collaboration

    1998-09-25

    Estimation of leaf photosynthetic rate (A) from leaf nitrogen content (N) is both conceptually and numerically important in models of plant, ecosystem and biosphere responses to global change. The relationship between A and N has been studied extensively at ambient CO{sub 2} but much less at elevated CO{sub 2}. This study was designed to (1) assess whether the A-N relationship was more similar for species within than between community and vegetation types, and (2) examine how growth at elevated CO{sub 2} affects the A-N relationship. Data were obtained for 39 C{sub 3} species grown at ambient CO{sub 2} and 10 C{sub 3} species grown at ambient and elevated CO{sub 2}. A regression model was applied to each species as well as to species pooled within different community and vegetation types. Cluster analysis of the regression coefficients indicated that species measured at ambient CO{sub 2} did not separate into distinct groups matching community or vegetation type. Instead, most community and vegetation types shared the same general parameter space for regression coefficients. Growth at elevated CO{sub 2} increased photosynthetic nitrogen use efficiency for pines and deciduous trees. When species were pooled by vegetation type, the A-N relationship for deciduous trees expressed on a leaf-mass bask was not altered by elevated CO{sub 2}, while the intercept increased for pines. When regression coefficients were averaged to give mean responses for different vegetation types, elevated CO{sub 2} increased the intercept and the slope for deciduous trees but increased only the intercept for pines. There were no statistical differences between the pines and deciduous trees for the effect of CO{sub 2}. Generalizations about the effect of elevated CO{sub 2} on the A-N relationship, and differences between pines and deciduous trees will be enhanced as more data become available.

  17. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    PubMed

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  18. Nitrogen fertilizer factory effects on the amino acid and nitrogen content in the needles of Scots pine.

    PubMed

    Kupsinskiene, E

    2001-12-01

    The aim of the research was to evaluate the content of amino acids in the needles of Pinus sylvestris growing in the area affected by a nitrogen fertilizer factory and to compare them with other parameters of needles, trees, and sites. Three young-age stands of Scots pine were selected at a distance of 0.5 km, 5 km, and 17 km from the factory. Examination of the current-year needles in winter of the year 2000 revealed significant (p < 0.05) differences between the site at a 0.5-km distance from the factory and the site at a 17-km distance from the factory--with the site closest to the factory showing the highest concentrations of protein (119%), total arginine (166%), total other amino acids (depending on amino acid, the effect ranged between 119 and 149%), free arginine (771%), other free amino acids (glutamic acid, threonine, serine, lysine--depending on amino acid, the effect ranged between 162 and 234%), also the longest needles, widest diameter, largest surface area, and heaviest dry weight (respectively, 133, 110, 136, and 169%). The gradient of nitrogen concentration in the needles was assessed on the selected plots over the period of 1995-2000, with the highest concentration (depending on year, 119 to 153%) documented in the site located 0.5 km from the factory. Significant correlations were determined between the total amino acid contents (r = 0.448 -0.939, p < 0.05), some free amino acid (arginine, aspartic acid, glutamic acid, lysine, threonine, and serine) contents (r = 0.418 - 0.975, p < 0.05), and air pollutant concentration at the sites, the distance between the sites and the factory, and characteristics of the needles. No correlation was found between free or total arginine content and defoliation or retention of the needles. In conclusion, it was revealed that elevated mean monthly concentration of ammonia (26 microg m(-3)) near the nitrogen fertilizer factory caused changes in nitrogen metabolism, especially increasing (nearly eight times

  19. Nitrogen fertilizer factory effects on the amino acid and nitrogen content in the needles of Scots pine.

    PubMed

    Kupsinskiene, E

    2001-12-04

    The aim of the research was to evaluate the content of amino acids in the needles of Pinus sylvestris growing in the area affected by a nitrogen fertilizer factory and to compare them with other parameters of needles, trees, and sites. Three young-age stands of Scots pine were selected at a distance of 0.5 km, 5 km, and 17 km from the factory. Examination of the current-year needles in winter of the year 2000 revealed significant (p < 0.05) differences between the site at a 0.5-km distance from the factory and the site at a 17-km distance from the factory--with the site closest to the factory showing the highest concentrations of protein (119%), total arginine (166%), total other amino acids (depending on amino acid, the effect ranged between 119 and 149%), free arginine (771%), other free amino acids (glutamic acid, threonine, serine, lysine--depending on amino acid, the effect ranged between 162 and 234%), also the longest needles, widest diameter, largest surface area, and heaviest dry weight (respectively, 133, 110, 136, and 169%). The gradient of nitrogen concentration in the needles was assessed on the selected plots over the period of 1995-2000, with the highest concentration (depending on year, 119 to 153%) documented in the site located 0.5 km from the factory. Significant correlations were determined between the total amino acid contents (r = 0.448 -0.939, p < 0.05), some free amino acid (arginine, aspartic acid, glutamic acid, lysine, threonine, and serine) contents (r = 0.418 - 0.975, p < 0.05), and air pollutant concentration at the sites, the distance between the sites and the factory, and characteristics of the needles. No correlation was found between free or total arginine content and defoliation or retention of the needles. In conclusion, it was revealed that elevated mean monthly concentration of ammonia (26 microg m(-3)) near the nitrogen fertilizer factory caused changes in nitrogen metabolism, especially increasing (nearly eight times

  20. [Application of aspartic acid as a non-specific binding inhibitor in the enrichment of phosphopeptides with titanium dioxide].

    PubMed

    Chi, Ming; Bi, Wei; Lu, Zhuang; Song, Lina; Jia, Wei; Zhang, Yangjun; Qian, Xiaohong; Cai, Yun

    2010-02-01

    Titanium dioxide (TiO2) is one of metal oxides widely used for phosphopeptide enrichment in phosphoproteomic research nowadays. However it can bind to some non-phosphorylated peptides containing one or more aspartic acid residues and/or glutamic acid residues. These non-phosphorylated peptides can be eluted along with phosphorylated peptides and cause the reduction of the selectivity. Conventional inhibitors for the non-specific binding of non-phosphorylated peptides can often contaminate the ion source of mass spectrometry and therefore their applications are limited in liquid chromatography-mass spectrometry (LC-MS). In this study, aspartic acid was reported as a novel non-specific binding inhibitor for phosphopeptide enrichment by titanium dioxide. Firstly, the tryptic peptide mixtures of 3 and 9 standard proteins were used for the comparison of the enrichment efficiency of titanium dioxide. The effects with the presence of aspartic acid, glutamic acid and no-inhibitor in the enrichment systems were compared separately. The results showed that aspartic acid can greatly improve the selectivity of titanium dioxide for phosphopeptide enrichment. Then, aspartic acid was used for the enrichment of tryptic peptide mixture of C57BL/6J mouse liver lysate and good results were also obtained which demonstrated that aspartic acid was a promising non-specific binding inhibitor for complex biological samples. Besides, no contamination in the ion source occurred during the mass spectrometric analysis.

  1. Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway.

    PubMed

    Shabbir, Yasir; Khokhar, Muhammad Fahim; Shaiganfar, Reza; Wagner, Thomas

    2016-05-01

    This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO2) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO2 revealed that the concentrations were higher within major cities along the highway. The highest NO2 vertical column densities (NO2 VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO2 VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.

  2. The economic benefits of reducing the levels of nitrogen dioxide (NO2) near primary schools: The case of London.

    PubMed

    Guerriero, Carla; Chatzidiakou, Lia; Cairns, John; Mumovic, Dejan

    2016-10-01

    Providing a healthy school environment is a priority for child health. The aim of this study is to develop a methodology that allows quantification of the potential economic benefit of reducing indoor exposure to nitrogen dioxide (NO2) in children attending primary schools. Using environmental and health data collected in primary schools in London, this study estimates that, on average, 82 asthma exacerbations per school can be averted each year by reducing outdoor NO2 concentrations. The study expands upon previous analyses in two ways: first it assesses the health benefits of reducing children's exposure to indoor NO2 while at school, second it considers the children's perspective in the economic evaluation. Using a willingness to pay approach, the study quantifies that the monetary benefits of reducing children's indoor NO2 exposure while at school would range between £2.5 k per school if a child's perspective based on child's budget is adopted up to £60 k if a parent's perspective is considered. This study highlights that designers, engineers, policymakers and stakeholders need to consider the reduction of outdoor pollution, and particularly NO2 levels, near primary schools as there may be substantial health and monetary benefits. PMID:27451292

  3. Seasonal variation of indoor and outdoor air quality of nitrogen dioxide in homes with gas and electric stoves.

    PubMed

    Dėdelė, Audrius; Miškinytė, Auksė

    2016-09-01

    Indoor air pollution significantly influences personal exposure to air pollution and increases health risks. Nitrogen dioxide (NO2) is one of the major air pollutants, and therefore it is important to properly determine indoor concentration of this pollutant considering the fact that people spend most of their time inside. The aim of this study was to assess indoor and outdoor concentration of NO2 during each season; for this purpose, passive sampling was applied. We analyzed homes with gas and electric stoves to determine and compare the concentrations of NO2 in kitchen, living room, and bedroom microenvironments (MEs). The accuracy of passive sampling was evaluated by comparing the sampling results with the data from air quality monitoring stations. The highest indoor concentration of NO2 was observed in kitchen ME during the winter period, the median concentration being 28.4 μg m(-3). Indoor NO2 levels in homes with gas stoves were higher than outdoor levels during all seasons. The concentration of NO2 was by 2.5 times higher in kitchen MEs with gas stoves than with electric stoves. This study showed that the concentration of NO2 in indoor MEs mainly depended on the stove type used in the kitchen. Homes with gas stoves had significantly higher levels of NO2 in all indoor MEs compared with homes where electric stoves were used. PMID:27250086

  4. MAX-DOAS measurements of nitrogen dioxide at the high altitude sites Zugspitze (2964 m) and Pico Espejo (4765 m)

    NASA Astrophysics Data System (ADS)

    Schreier, Stefan F.; Richter, Andreas; Wittrock, Folkard; Burrows, John P.

    2015-04-01

    Spectral measurements at two mountain sites were performed with a MAX-DOAS (Multi AXis Differential Optical Absorption Spectroscopy) instrument from February to July 2003 (Zugspitze, Germany) and from March 2004 to November 2008 (Pico Espejo, Venezuela). Here, these measurements are used for the retrieval of slant column densities (SCDs) of nitrogen dioxide (NO2). While at the altitude of observations the NO2 levels are usually small, uplifting of anthropogenic emissions from the valley and in Venezuela also transport of emissions from biomass burning can lead to significant enhancements. Daily, weekly, and seasonal cycles of NO2 SCDs are shown for the two stations, linked to different meteorological conditions and compared between the two sites. In a next step, a preliminary approach to derive vertical column densities (VCDs) is presented. VCDs of NO2 from ground-based MAX-DOAS instruments provide useful information for the validation of satellite instruments such as SCIAMACHY, OMI, and GOME-2. Comparisons between ground-based and satellite-based NO2 VCDs are shown for selected periods.

  5. Analysis of Mexico City urban air pollution using nitrogen dioxide column density measurements from UV/Visible spectroscopy

    NASA Astrophysics Data System (ADS)

    Garcia Payne, D. G.; Grutter, M.; Melamed, M. L.

    2010-12-01

    The differential optical absorption spectroscopy method (DOAS) was used to get column densities of nitrogen dioxide (NO2) from the analysis of zenith sky UV/visible spectra. Since the optical path length provides critical information in interpreting NO2 column densities, in conjunction with NO2 column densities, the oxygen dimer (O4) column density was retrieved to give insight into the optical path length. We report observations of year round NO2 and O4 column densities (from august 2009 to september 2010) from which the mean seasonal levels and the daily evolution, as well as the occurrence of elevated pollution episodes are examined. Surface nitric oxide (NO) and NO2 from the local monitoring network, as well as wind data and the vertical aerosol density from continuous Lidar measurements are used in the analysis to investigate specific events in the context of local emissions from vehicular traffic, photochemical production and transport from industrial emissions. The NO2 column density measurements will enhance the understanding Mexico City urban air pollution. Recent research has begun to unravel the complexity of the air pollution problem in Mexico City and its effects not only locally but on a regional and global scale as well.

  6. Effect of nitrogen dioxide, ozone, and peroxyacetyl nitrate on metabolic and pulmonary function. Research report, September 1983-October 1986

    SciTech Connect

    Drechsler-Parks, D.M.

    1987-04-01

    The report is the first published account of the pulmonary and metabolic effects of oxidant air pollutants on healthy men and women, middle-aged and older, compared with young adults of either gender. Dr. Drechsler-Parks exposed each of 32 subjects to 0.13 ppm peroxyacetyl nitrate, 0.45 ppm ozone, 0.6 ppm nitrogen dioxide and air, plus a combination of two, and then all three, of the oxidant gases. Their responses to the exposures were measured after alternating periods of exercise and rest over a two-hour period. The results of the study were: (1) mixtures of gases did not cause an enhanced effect; (2) pulmonary effects were observed for ozone but not for the other gases; (3) women showed a slightly larger percentage decrement of lung function in response to ozone than did men; and (4) older people (51 to 76 years) may be less responsive to ozone than are younger people (18 to 26 years). The author discusses the significance, limitations, and interpretations of these findings in detail.

  7. Impact of personal and ambient-level exposures to nitrogen dioxide and particulate matter on cardiovascular function

    PubMed Central

    Williams, Ron; Brook, Rob; Bard, Rob; Conner, Teri; Shin, Hwashin; Burnett, Rick

    2011-01-01

    This work explored the association between nitrogen dioxide (NO2) and PM2.5 components with changes in cardiovascular function in an adult non-smoking cohort. The cohort consisted of 65 volunteers participating in the US EPA’s Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), brachial artery diameter (BAD), brachial artery flow-mediated dilatation (FMD) and nitroglycerin-mediated arterial dilatation (NMD) were collected by in-home examinations. A maximum of 336 daily environmental and health effect observations were obtained. Daily potassium air concentrations were associated with significant decreases in DBP (−0.0447 mmHg/ng/m3 ± 0.0132, p = 0.0016, lag day 0) among participants compliant with the personal monitoring protocol. Personal NO2 exposures resulted in significant changes in BAD (e.g., 0.0041 mm/ppb ± 0.0019, p = 0.0353, lag day 1) and FMD (0.0612 ±0.0235, p = 0.0103, lag day 0) among other findings. PMID:21711166

  8. GASP - THERMODYNAMIC AND TRANSPORT PROPERTIES OF HELIUM, METHANE, NEON, NITROGEN, CARBON MONOXIDE, CARBON DIOXIDE, OXYGEN, AND ARGON

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1994-01-01

    A computer program, GASP, has been written to calculate the thermodynamic and transport properties of argon, carbon dioxide, carbon monoxide, fluorine, methane, neon, nitrogen, and oxygen. GASP accepts any two of pressure, temperature, or density as input. In addition, entropy and enthalpy are possible inputs. Outputs are temperature, density, pressure, entropy, enthalpy, specific heats, expansion coefficient, sonic velocity, viscosity, thermal conductivity, and surface tension. A special technique is provided to estimate the thermal conductivity near the thermodynamic critical point. GASP is a group of FORTRAN subroutines. The user typically would write a main program that invoked GASP to provide only the described outputs. Subroutines are structured so that the user may call only those subroutines needed for his particular calculations. Allowable pressures range from 0.l atmosphere to 100 to l,000 atmospheres, depending on the fluid. Similarly, allowable pressures range from the triple point of each substance to 300 degrees K to 2000 degrees K, depending on the substance. The GASP package was developed to be used with heat transfer and fluid flow applications. It is particularly useful in applications of cryogenic fluids. Some problems associated with the liquefication, storage, and gasification of liquefied natural gas and liquefied petroleum gas can also be studied using GASP. This program is written in FORTRAN IV for batch execution and is available for implementation on IBM 7000 series computers. GASP was developed in 1971.

  9. Stratospheric profiles of nitrogen dioxide observed by Optical Spectrograph and Infrared Imager System on the Odin satellite

    NASA Astrophysics Data System (ADS)

    Sioris, Christopher E.; Haley, Craig S.; McLinden, Chris A.; von Savigny, Christian; McDade, Ian C.; McConnell, Jack C.; Evans, Wayne F. J.; Lloyd, Nicholas D.; Llewellyn, Edward J.; Chance, Kelly V.; Kurosu, Thomas P.; Murtagh, Donal; Frisk, Urban; Pfeilsticker, Klaus; BöSch, Hartmut; Weidner, Frank; Strong, Kimberly; Stegman, Jacek; MéGie, GéRard

    2003-04-01

    Vertical profiles of nitrogen dioxide in the 19-40 km altitude range are successfully retrieved over the globe from Optical Spectrograph and Infrared Imager System (OSIRIS) limb scatter observations in late 2001 and early 2002. The inclusion of multiple scattering in the radiative transfer model used in the inversion algorithm allows for the retrieval of NO2 down to 19 km. The slant column densities, which represent the observations in the inversion, are obtained by fitting the fine structure in normalized radiance spectra over the 435-449 nm range, where NO2 electronic absorption is readily observable because of long light paths through stratospheric layers rich in this constituent. Details of the spectral fitting and inversion algorithm are discussed, including the discovery of a pseudo-absorber associated with pixelated detectors and a new method to verify altitude registration. Comparisons are made with spatially and temporally coincident profile measurements of this photochemically active trace gas. Better than 20% agreement is obtained with all correlative measurements over the common retrieval altitude range, confirming the validity of OSIRIS NO2 profiles. Systematic biases in the number densities are not observed at any altitude. A "snapshot" meridional cross section between 40°N and 70°S is shown from observations during a fraction of an orbit.

  10. Seasonal variation of indoor and outdoor air quality of nitrogen dioxide in homes with gas and electric stoves.

    PubMed

    Dėdelė, Audrius; Miškinytė, Auksė

    2016-09-01

    Indoor air pollution significantly influences personal exposure to air pollution and increases health risks. Nitrogen dioxide (NO2) is one of the major air pollutants, and therefore it is important to properly determine indoor concentration of this pollutant considering the fact that people spend most of their time inside. The aim of this study was to assess indoor and outdoor concentration of NO2 during each season; for this purpose, passive sampling was applied. We analyzed homes with gas and electric stoves to determine and compare the concentrations of NO2 in kitchen, living room, and bedroom microenvironments (MEs). The accuracy of passive sampling was evaluated by comparing the sampling results with the data from air quality monitoring stations. The highest indoor concentration of NO2 was observed in kitchen ME during the winter period, the median concentration being 28.4 μg m(-3). Indoor NO2 levels in homes with gas stoves were higher than outdoor levels during all seasons. The concentration of NO2 was by 2.5 times higher in kitchen MEs with gas stoves than with electric stoves. This study showed that the concentration of NO2 in indoor MEs mainly depended on the stove type used in the kitchen. Homes with gas stoves had significantly higher levels of NO2 in all indoor MEs compared with homes where electric stoves were used.

  11. Determinants of personal exposure to some carcinogenic substances and nitrogen dioxide among the general population in five Swedish cities.

    PubMed

    Hagenbjörk-Gustafsson, Annika; Tornevi, Andreas; Andersson, Eva M; Johannesson, Sandra; Bellander, Tom; Merritt, Anne-Sophie; Tinnerberg, Håkan; Westberg, Håkan; Forsberg, Bertil; Sallsten, Gerd

    2014-07-01

    Environmental levels of airborne carcinogenic and related substances are comparatively better known than individual exposure and its determinants. We report on a personal monitoring program involving five Swedish urban populations. The aim of the program was to investigate personal exposure to benzene, 1,3-butadiene, formaldehyde, and nitrogen dioxide (NO2). The measurements were performed among 40 inhabitants during seven consecutive days, in one urban area each year, during 2000-2008. The estimated population exposure levels were 1.95 μg/m(3) for benzene, 0.56 μg/m(3) for 1,3-butadiene, 19.4 μg/m(3) for formaldehyde, and 14.1 μg/m(3) for NO2. Statistical analysis using a mixed-effects model revealed that time spent in traffic and time outdoors contributed to benzene and 1,3- butadiene exposure. For benzene, refueling a car was an additional determinant influencing the exposure level. Smoking or environmental tobacco smoke were significant determinants of exposure to NO2, benzene, and 1,3-butadiene. Those with a gas stove had higher NO2 exposure. Living in a single-family house increased the exposure to formaldehyde significantly. In a variance component model, the between-subject variance dominated for 1,3-butadiene and formaldehyde, whereas the between-city variance dominated for NO2. For benzene, the between-subject and between-cities variances were similar.

  12. Assessing traffic and industrial contributions to ambient nitrogen dioxide and volatile organic compounds in a low pollution urban environment.

    PubMed

    Oiamo, Tor H; Johnson, Markey; Tang, Kathy; Luginaah, Isaac N

    2015-10-01

    Land use regression (LUR) modeling is an effective method for estimating fine-scale distributions of ambient air pollutants. The objectives of this study are to advance the methodology for use in urban environments with relatively low levels of industrial activity and provide exposure assessments for research on health effects of air pollution. Intraurban distributions of nitrogen dioxide (NO2) and the volatile organic compounds (VOCs) benzene, toluene and m- and p-xylene were characterized based on spatial monitoring and LUR modeling in Ottawa, Ontario, Canada. Passive samplers were deployed at 50 locations throughout Ottawa for two consecutive weeks in October 2008 and May 2009. Land use variables representing point, area and line sources were tested as predictors of pooled pollutant distributions. LUR models explained 96% of the spatial variability in NO2 and 75-79% of the variability in the VOC species. Proximity to highways, green space, industrial and residential land uses were significant in the final models. More notably, proximity to industrial point sources and road network intersections were significant predictors for all pollutants. The strong contribution of industrial point sources to VOC distributions in Ottawa suggests that facility emission data should be considered whenever possible. The study also suggests that proximity to road network intersections may be an effective proxy in areas where reliable traffic data are not available.

  13. Use of GIS and ancillary variables to predict volatile organic compound and nitrogen dioxide levels at unmonitored locations

    NASA Astrophysics Data System (ADS)

    Smith, Luther; Mukerjee, Shaibal; Gonzales, Melissa; Stallings, Casson; Neas, Lucas; Norris, Gary; Özkaynak, Halûk

    In late 1999, passive air sampling of nitrogen dioxide (NO 2) and volatile organic compounds was conducted at 22 school locations and two intensive sites in El Paso, Texas. Our goal was to predict concentrations of NO 2 and benzene, toluene, ethylbenzene, o-xylene, and m, p-xylene at a total of 55 schools. The predictive equations were developed by regressing the passive monitor measurements at the 22 monitored schools on land-use variables derived from a geographic information system (GIS). These GIS-based ancillary variables included distance to the nearest border crossing, elevation, population density, distance to roads with specified traffic volumes, traffic intensity around the schools, and distance to the nearest petroleum facility. The reliability of the predictive equations was assessed at the two intensive monitoring sites. For all pollutants, the most useful predictive ancillary variables were elevation, population density, distance to a border crossing, and distance to a petroleum facility. For estimating NO 2, traffic intensity was also important.

  14. Experimental exposures of young asthmatic volunteers to 0. 3 ppm nitrogen dioxide and to ambient air pollution

    SciTech Connect

    Avol, E.L.; Linn, W.S.; Peng, R.C.; Whynot, J.D.; Shamoo, D.A.; Little, D.E.; Smith, M.N.; Hackney, J.D. )

    1989-12-01

    Asthmatic volunteers aged 8 to 16 (N = 34) were exposed on separate occasions to clean air (control), to 0.30 ppm nitrogen dioxide (NO{sub 2}) in otherwise clean air, and to polluted Los Angeles area ambient air on summer mornings when NO2 pollution was expected. Exposures lasted 3 hr, with alternating 10-min periods of exercise and rest. In ambient pollution exposures, 3-hr average NO{sub 2} concentrations ranged from 0.01 to 0.26 ppm, with a mean of 0.09 ppm. Ambient exposures did not significantly affect lung function, symptoms, or bronchial reactivity to cold air, relative to the control condition. Responses to 0.3 ppm NO{sub 2} exposures were equivocal. Asthma symptoms were more severe during 1-week periods before 0.3 ppm exposures, and lung function was decreased immediately before 0.3 ppm exposures, compared to other conditions. Lung function declined slightly during the first hour at 0.3 ppm, but improved over the remaining 2 hr. Compared to other conditions, symptoms were not increased during 0.3 ppm exposures, but were increased during 1-week periods afterward. These observations may reflect untoward effects of 0.3 ppm NO{sub 2}, or may reflect chance increases in asthma severity prior to 0.3 ppm exposures.

  15. The economic benefits of reducing the levels of nitrogen dioxide (NO2) near primary schools: The case of London.

    PubMed

    Guerriero, Carla; Chatzidiakou, Lia; Cairns, John; Mumovic, Dejan

    2016-10-01

    Providing a healthy school environment is a priority for child health. The aim of this study is to develop a methodology that allows quantification of the potential economic benefit of reducing indoor exposure to nitrogen dioxide (NO2) in children attending primary schools. Using environmental and health data collected in primary schools in London, this study estimates that, on average, 82 asthma exacerbations per school can be averted each year by reducing outdoor NO2 concentrations. The study expands upon previous analyses in two ways: first it assesses the health benefits of reducing children's exposure to indoor NO2 while at school, second it considers the children's perspective in the economic evaluation. Using a willingness to pay approach, the study quantifies that the monetary benefits of reducing children's indoor NO2 exposure while at school would range between £2.5 k per school if a child's perspective based on child's budget is adopted up to £60 k if a parent's perspective is considered. This study highlights that designers, engineers, policymakers and stakeholders need to consider the reduction of outdoor pollution, and particularly NO2 levels, near primary schools as there may be substantial health and monetary benefits.

  16. Assessing traffic and industrial contributions to ambient nitrogen dioxide and volatile organic compounds in a low pollution urban environment.

    PubMed

    Oiamo, Tor H; Johnson, Markey; Tang, Kathy; Luginaah, Isaac N

    2015-10-01

    Land use regression (LUR) modeling is an effective method for estimating fine-scale distributions of ambient air pollutants. The objectives of this study are to advance the methodology for use in urban environments with relatively low levels of industrial activity and provide exposure assessments for research on health effects of air pollution. Intraurban distributions of nitrogen dioxide (NO2) and the volatile organic compounds (VOCs) benzene, toluene and m- and p-xylene were characterized based on spatial monitoring and LUR modeling in Ottawa, Ontario, Canada. Passive samplers were deployed at 50 locations throughout Ottawa for two consecutive weeks in October 2008 and May 2009. Land use variables representing point, area and line sources were tested as predictors of pooled pollutant distributions. LUR models explained 96% of the spatial variability in NO2 and 75-79% of the variability in the VOC species. Proximity to highways, green space, industrial and residential land uses were significant in the final models. More notably, proximity to industrial point sources and road network intersections were significant predictors for all pollutants. The strong contribution of industrial point sources to VOC distributions in Ottawa suggests that facility emission data should be considered whenever possible. The study also suggests that proximity to road network intersections may be an effective proxy in areas where reliable traffic data are not available. PMID:26022404

  17. Tropospheric Nitrogen Dioxide Column Density Trends Seen from the 10-year Record of OMI Measurements over East Asia

    NASA Astrophysics Data System (ADS)

    Irie, H.; Muto, T.; Itahashi, S.; Kurokawa, J. I.

    2015-12-01

    The Ozone Monitoring Instrument (OMI) aboard the Aura satellite recorded the 10-year (2005-2014) of tropospheric nitrogen dioxide (NO2) vertical column density (VCD) data. The data set taken over East Asia was analyzed to estimate linear trends on national and grid bases for two periods of 2005-2011 and 2011-2014. The most striking features are leveling-off or decreasing trends seen in NO2 VCDs over China for 2011-2014 after continuous increases for 2005-2011. In particular, a significant reduction by ~14% occurred from 2013 through 2014, attaining to the level of 2009. The grid-basis trend analysis implies that the turnaround seen in the trends occurred on a province or larger spatial scale and was likely due mainly to the technical improvement such as the widespread use of de-NOx units. Another prominent features are seen in Japan, where NO2 VCDs decreased at a rate of ~4% per year from 2005 to 2011. The rate was almost unchanged between the two periods 2005-2011 and 2011-2014, while the significant power substitution of thermal power generation for the nuclear power generation took place in Japan after 2011, when a massive earthquake occurred off the Pacific coast of northern Japan. This reflects a less contribution of NOx emissions from the power plant sector than that from the transport sector in the Pacific Belt Zone lying over metropolitan areas.

  18. Tropospheric ozone and nitrogen dioxide measurements in urban and rural regions as seen by IASI and GOME-2

    NASA Astrophysics Data System (ADS)

    Safieddine, S.; Clerbaux, C.; George, M.; Hadji-Lazaro, J.; Hurtmans, D.; Coheur, P.-F.; Wespes, C.; Loyola, D.; Valks, P.; Hao, N.

    2013-09-01

    ozone (O3) columns in urban and rural regions as seen by the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed along with the Global Ozone Monitoring Experiment (GOME-2) tropospheric nitrogen dioxide (NO2) columns. Results over nine cities of the Northern Hemisphere for the period 2008-2011 show a typical seasonal behavior of tropospheric O3, with a first maximum reached in late spring because of stratospheric intrusion mainly and a continuous rise till the summer because of the anthropogenic-based ozone production. Over the East Asian cities, a decrease in the O3 tropospheric column is detected during the monsoon period. Seasonal cycling of tropospheric NO2 shows consistent higher values during winter because of the higher anthropogenic sources and longer lifetime. In rural regions, a complex relation between the O3 and NO2 columns is found, with good correlation in summer and winter. O3 concentrations in rural sites are found to be comparable to those closest to the anthropogenic emission sources, with peak values in spring and summer. Furthermore, the effect of the reduction of pollutant emissions in the Beijing region during the Olympic Games of 2008 compared to the same summer period in the following 3 years is studied. GOME-2 NO2 measurements show a reduction up to 54% above Beijing during this period compared to the following 3 years. IASI O3 measurements show an increase of 12% during July 2008 followed by a decrease of 5-6% during the months of August and September.

  19. Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway.

    PubMed

    Shabbir, Yasir; Khokhar, Muhammad Fahim; Shaiganfar, Reza; Wagner, Thomas

    2016-05-01

    This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO2) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO2 revealed that the concentrations were higher within major cities along the highway. The highest NO2 vertical column densities (NO2 VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO2 VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas. PMID:27155404

  20. Inter-Comparison of Nitrogen Dioxide Column Densities Retrieved by Ground-Based Max-Doas Under Different Instrumental Conditions Over Mainz

    NASA Astrophysics Data System (ADS)

    Bruchkouski, I.; Dziomin, V.; Ortega, I.; Volkamer, R.; Krasouski, A.

    2013-12-01

    This study is dedicated to the instrumental differences between ground-based MAX-DOAS measurement devices. Our MAX-DOAS instrument, which has been developed at the National Ozone Monitoring Research & Education Center of the Belarusian State University for the purpose of nitrogen dioxide and other atmospheric trace gases monitoring over Belarus, features a rotating mirror and a telescope directly connected to the spectrometer with a two-dimensional CCD detector. Using a mirror instead of an optical fibre makes it possible to change the field of view of the telescope, and the whole instrument is rather compact and all its components are placed outdoors in the open air. However, this makes it quite difficult to ensure a top-quality thermostabilization. In the course of the MAX-DOAS campaign, which took place in the Max Planck Institute for Chemistry in Mainz, Germany in summer of 2013, we had a great opportunity to compare our instrument with other devices of different types. In the present study we make a comparison of nitrogen dioxide slant column densities (SCDs) during several days obtained by our instrument with that measured by the device from the Department of Chemistry and Biochemistry, University of Colorado (Boulder), which has a thermostabilization level of about 0.01 degrees Celsius. We investigate the influence of the spectrometer parts thermostabilization on nitrogen dioxide SCDs retrieval. Furthermore, it was possible to modify the telescope field of view for our instrument from 0.005 to 1.3 degrees, so we performed nitrogen dioxide SCDs retrieval for different fields of view at the same angle of elevation. We analyze these measurement results and obtain an optimal field of view with the aim to achieve the highest possible signal to noise ratio.

  1. Role of fatty acid composites in the toxicity of titanium dioxide nanoparticles used in cosmetic products.

    PubMed

    Chang, JuOae; Lee, Chang-Woo; Alsulimani, Helal Hussain; Choi, Jee Eun; Lee, Joo-Kyung; Kim, AhYoung; Park, Bae Ho; Kim, Jonghan; Lee, HeaYeon

    2016-01-01

    It has been recognized that the use of nanoparticles (NPs) in the cosmetic industry results in products with better efficacy and functionality. However, recent advances in molecular toxicology have revealed that NP exposure can promote cytotoxicity and oxidative damage, which has raised health concerns in the use of NPs in personal care products. Nevertheless, the mechanistic basis for the toxicity and safety of cosmetic NPs is poorly understood. The goal of the study was to determine the cytotoxicity and intracellular distribution of titanium dioxide (TiO2) NPs containing fatty acid composites (palmitoleic acid, palmitic acid, stearic acid and oleic acid) commonly used in cosmetic products. Two types of cells, human fibroblast skin cells and adenocarcinoma lung cells, were exposed to either bare TiO2 NPs or TiO2 NPs mixed with fatty acids for up to 48 hr. NMR analysis confirmed that the fatty acid composites remained in the NPs after wash. The cytotoxicity of TiO2 NPs was determined by cell viability measurement using quantitative confocal microscopy, and the localization of two different forms of TiO2 NPs were assessed using electron spectroscopic imaging with transmission electron microscopy. TiO2 NPs containing fatty acids posed significantly reduced cytotoxicity (80-88% decreases) than bare NPs in both cell types. Furthermore, there was less intracellular penetration of the NPs containing fatty acid composites compared with bare NPs. These results provide important insights into the role of fatty acids in protecting the cells from possible toxicity caused by NPs used in the production of cosmetic products.

  2. Role of fatty acid composites in the toxicity of titanium dioxide nanoparticles used in cosmetic products.

    PubMed

    Chang, JuOae; Lee, Chang-Woo; Alsulimani, Helal Hussain; Choi, Jee Eun; Lee, Joo-Kyung; Kim, AhYoung; Park, Bae Ho; Kim, Jonghan; Lee, HeaYeon

    2016-01-01

    It has been recognized that the use of nanoparticles (NPs) in the cosmetic industry results in products with better efficacy and functionality. However, recent advances in molecular toxicology have revealed that NP exposure can promote cytotoxicity and oxidative damage, which has raised health concerns in the use of NPs in personal care products. Nevertheless, the mechanistic basis for the toxicity and safety of cosmetic NPs is poorly understood. The goal of the study was to determine the cytotoxicity and intracellular distribution of titanium dioxide (TiO2) NPs containing fatty acid composites (palmitoleic acid, palmitic acid, stearic acid and oleic acid) commonly used in cosmetic products. Two types of cells, human fibroblast skin cells and adenocarcinoma lung cells, were exposed to either bare TiO2 NPs or TiO2 NPs mixed with fatty acids for up to 48 hr. NMR analysis confirmed that the fatty acid composites remained in the NPs after wash. The cytotoxicity of TiO2 NPs was determined by cell viability measurement using quantitative confocal microscopy, and the localization of two different forms of TiO2 NPs were assessed using electron spectroscopic imaging with transmission electron microscopy. TiO2 NPs containing fatty acids posed significantly reduced cytotoxicity (80-88% decreases) than bare NPs in both cell types. Furthermore, there was less intracellular penetration of the NPs containing fatty acid composites compared with bare NPs. These results provide important insights into the role of fatty acids in protecting the cells from possible toxicity caused by NPs used in the production of cosmetic products. PMID:27432239

  3. Nitrogen oxides reduction by carbonaceous materials and carbon dioxide separation using regenerative metal oxides from fossil fuel based flue gas

    NASA Astrophysics Data System (ADS)

    Gupta, Himanshu

    The ever-growing energy demands due to rising global population and continuing lifestyle improvements has placed indispensable emphasis on fossil fuels. Combustion of fossil fuels leads to the emission of harmful gaseous pollutants such as oxides of sulfur (SOx) and nitrogen (NOx), carbon dioxide (CO2), mercury, particulate matter, etc. Documented evidence has proved that this air pollution leads to adverse environmental health. This dissertation focuses on the development of technologies for the control of NOx and CO2 emissions. The first part of the thesis (Chapters 2--6) deals with the development of carbon based post combustion NOx reduction technology called CARBONOX process. High temperature combustion oxidizes both atmospheric nitrogen and organic nitrogen in coal to nitric oxide (NO). The reaction rate between graphite and NO is slow and requires high temperature (>900°C). The presence of metallic species in coal char catalyzes the reaction. The reaction temperature is lowered in the presence of oxygen to about 600--850°C. Chemical impregnation, specifically sodium compounds, further lowers the reaction temperature to 350--600°C. Activated high sodium lignite char (HSLC) provided the best performance for NO reduction. The requirement of char for NOx reduction is about 8--12 g carbon/g NO reduced in the presence of 2% oxygen in the inlet gas. The second part of this dissertation (chapter 7--8) focuses on the development of a reaction-based process for the separation of CO2 from combustion flue gas. Certain metal oxides react with CO2 forming metal carbonates under flue gas conditions. They can be calcined separately to yield CO2. Calcium oxide (CaO) has been identified as a viable metal oxide for the carbonation-calcination reaction (CCR) scheme. CaO synthesized from naturally occurring precursors (limestone and dolomite) attained 45--55% of their stoichiometric conversion due to the susceptibility of their microporous structure. High surface area

  4. Amino acid nitrogen isotopic composition patterns in lacustrine sedimenting matter

    NASA Astrophysics Data System (ADS)

    Carstens, Dörte; Lehmann, Moritz F.; Hofstetter, Thomas B.; Schubert, Carsten J.

    2013-11-01

    Amino acids (AAs) comprise a large fraction of organic nitrogen (N) in plankton and sedimenting matter. Aquatic studies of organic N compounds in general and of AAs in particular, mostly concentrate on marine environments. In order to study the cycling and fate of organic N and AAs in lakes, we measured the N isotopic composition (δ15N) of bulk organic matter (OM) and of single hydrolysable AAs in sediment trap and sediment samples from two Swiss lakes with contrasting trophic state: Lake Brienz, an oligotrophic lake with an oxic water column, and Lake Zug a eutrophic, meromictic lake. We also measured the N isotopic composition of water column nitrate, the likely inorganic N source during biosynthesis in both lakes. The δ15N-AA patterns found for the sediment trap material were consistent with published δ15N-AA data for marine plankton. The AA composition and primary δ15N-AA signatures are preserved until burial in the sediments. During early sedimentary diagenesis, the δ15N values of single AAs appear to increase, exceeding those of the bulk OM. This increase in δ15N-AA is paralleled by a decreased contribution of AAs to the total OM pool with progressed degradation, suggesting preferential AA degradation associated with a significant N isotope fractionation. Indicators for trophic level based on δ15N-AAs were determined, for the first time in lacustrine systems. In our samples, the trophic AAs were generally enriched in 15N compared to source AAs and higher trophic δ15N-AA values in Lake Zug were consistent with a higher trophic level of the bulk biomass compared to Lake Brienz. Especially the difference between average trophic δ15N-AAs and average source δ15N-AAs was sensitive to the trophic states of the two lakes. A proxy for total heterotrophic AA re-synthesis (ΣV), which is strongly associated with heterotrophic microbial reworking of the OM, was calculated based on δ15N values of trophic AAs. Higher ΣV in Lake Brienz indicate enhanced

  5. Utilization of ammonium as a nitrogen source: effects of ambient acidity on growth and nitrogen accumulation by soybean

    NASA Technical Reports Server (NTRS)

    Tolley-Henry, L.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1986-01-01

    Dry matter accumulation of plants utilizing NH4+ as the sole nitrogen source generally is less than that of plants receiving NO3- unless acidity of the root-zone is controlled at a pH of about 6.0. To test the hypothesis that the reduction in growth is a consequence of nitrogen stress within the plant in response to effects of increased acidity during uptake of NH4+ by roots, nonnodulated soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 24 days in flowing nutrient culture containing 1.0 millimolar NH4+ as the nitrogen source. Acidities of the culture solutions were controlled at pH 6.1, 5.1, and 4.1 +/- 0.1 by automatic additions of 0.01 N H2SO4 or Ca(OH)2. Plants were sampled at intervals of 3 to 4 days for determination of dry matter and nitrogen accumulation. Rates of NH4+ uptake per gram root dry weight were calculated from these data. Net CO2 exchange rates per unit leaf area were measured on attached leaves by infrared gas analysis. When acidity of the culture solution was increased from pH 6.1 to 5.1, dry matter and nitrogen accumulation were reduced by about 40% within 14 days. Net CO2 exchange rates per unit leaf area, however, were not affected, and the decreased growth was associated with a reduction in rates of appearance and expansion of new leaves. The uptake rates of NH4+ per gram root were about 25% lower throughout the 24 days at pH 5.1 than at 6.1. A further increase in solution acidity from pH 5.1 to 4.1 resulted in cessation of net dry matter production and appearance of new leaves within 10 days. Net CO2 exchange rates per unit leaf area declined rapidly until all viable leaves had abscised by 18 days. Uptake rates of NH4+, which were initially about 50% lower at pH 4.1 than at 6.1 continued to decline with time of exposure until net uptake ceased at 10 days. Since these responses also are characteristic of the sequence of responses that occur during onset and progression of a nitrogen stress, they corroborate our hypothesis.

  6. Enhanced sulfate formation by nitrogen dioxide: Implications from in situ observations at the SORPES station

    NASA Astrophysics Data System (ADS)

    Xie, Yuning; Ding, Aijun; Nie, Wei; Mao, Huiting; Qi, Ximeng; Huang, Xin; Xu, Zheng; Kerminen, Veli-Matti; Petäjä, Tuukka; Chi, Xuguang; Virkkula, Aki; Boy, Michael; Xue, Likun; Guo, Jia; Sun, Jianning; Yang, Xiuqun; Kulmala, Markku; Fu, Congbin

    2015-12-01

    Investigating sulfate formation processes is important not only for air pollution control but also for understanding the climate system. Although the mechanisms of secondary sulfate production have been widely studied, in situ observational evidence implicating an important role of NO2 in SO2 oxidation in the real atmosphere has been rare. In this study, we report two unique cases, from an intensive campaign conducted at the Station for Observing Regional Processes of the Earth System (SORPES) in East China, showing distinctly different mechanisms of sulfate formation by NO2 and related nitrogen chemistry. The first case occurred in an episode of mineral dust mixed with anthropogenic pollutants and especially high concentrations of NOx. It reveals that NO2 played an important role, not only in surface catalytic reactions of SO2 but also in dust-induced photochemical heterogeneous reactions of NO2, which produced additional sources of OH radicals to promote new particle formation and growth. The second case was caused by aqueous oxidation of S(IV) by NO2 under foggy/cloudy conditions with high NH3 concentration. As a by-product, the formed nitrite enhanced HONO formation and further promoted the gas-phase formation of sulfate in the downwind area. This study highlights the effect of NOx in enhancing the atmospheric oxidizing capacity and indicates a potentially very important impact of increasing NOx on particulate pollution formation and regional climate change in East Asia.

  7. Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Liang, J.; Qi, X.; Souza, L.; Luo, Y.

    2015-10-01

    Nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive researches have been done to explore whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in plant and litter pools but not in soil pool. Thus, the basis of PNL occurrence partially exists. However, CO2 enrichment also significantly increased the N influx via biological N fixation, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth over time was observed. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions. Moreover, our synthesis showed that CO2 enrichment increased soil ammonium (NH4+) but decreased nitrate (NO3-). The different responses of NH4+ and NO3-, and the consequent biological processes, may result in changes in soil microenvironment, community structures and above-belowground interactions, which could potentially affect the terrestrial biogeochemical cycles and the feedback to climate change.

  8. The study of visible light active bismuth modified nitrogen doped titanium dioxide photocatlysts: Role of bismuth

    NASA Astrophysics Data System (ADS)

    Bagwasi, Segomotso; Niu, Yuxiao; Nasir, Muhammad; Tian, Baozhu; Zhang, Jinlong

    2013-01-01

    Bismuth modified nitrogen doped TiO2 nanoparticles have been successfully prepared by two steps synthesis route which includes hydrothermal and impregnation hydrolysis method. Samples were characterized using X-ray diffraction (XRD), N2 physical adsorption, Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier Transmission Infrared (FTIR), Raman, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PLS) technologies. The preparatory method afforded the production of well crystallized spherical Bi modified N-doped TiO2 nanoparticles with varied amounts of Bi content. XRD analysis results reveal that Bi exists as rare metastable Bi20TiO32 which started to surface at Bi loading content of 7 mol% in relation to Ti ions. All Bi modified N-TiO2 samples exhibited higher photocatalytic activity toward degradation of 2,4-DCP over N-TiO2 under visible light irradiation. The sample with 10% composition of the Bi20TiO32 exhibited the highest activity. The superior photocatalytic performance of 10%Bi/N-TiO2 is attributed to high visible light absorption as well as effective charge carrier separation. Therefore, the role of Bi species in the N-TiO2 is improvement of visible light harvesting and facilitation of charge carrier separation hence alleviating electron-hole recombination.

  9. Will elevated carbon dioxide concentration amplify the benefits of nitrogen fixation in legumes?

    SciTech Connect

    Rogers, A.; Ainsworth, E. A.; Leakey, A. D. B.

    2009-11-01

    Growth at elevated [CO{sub 2}] stimulates photosynthesis and increases carbon (C) supply in all C3 species. A sustained and maximal stimulation in productivity at elevated [CO{sub 2}] requires an enhanced nutrient supply to match the increase in C acquisition. The ability of legumes to exchange C for nitrogen (N) with their N{sub 2}-fixing symbionts has led to the hypothesis that legumes will have a competitive advantage over nonleguminous species when grown at elevated [CO{sub 2}]. On balance, evidence suggests that in managed systems, legumes are more responsive to elevated [CO{sub 2}] than other plants (e.g. Ainsworth and Long, 2005); however, in natural ecosystems, nutrient availability can limit the response of legumes to elevated [CO{sub 2}] (Hungate et al., 2004; van Groenigen et al., 2006). Here, we consider these observations, outline the mechanisms that underlie them, and examine recent work that advances our understanding of how legumes respond to growth at elevated [CO{sub 2}]. First we highlight the global importance of legumes and provide a brief overview of the symbiotic relationship.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. NOx and N2O precursors from biomass pyrolysis: nitrogen transformation from amino acid.

    PubMed

    Ren, Qiangqiang; Zhao, Changsui

    2012-04-01

    Large quantities of NO(x) and N(2)O emissions can be produced from biomass burning. Understanding nitrogen behavior during biomass pyrolysis is crucial. Nitrogen in biomass is mainly in forms of proteins (amino acids). Phenylalanine, aspartic acid, and glutamic acid were used as the model compounds for the nitrogen in biomass. Release behavior tests of nitrogen species from the three amino acids during pyrolysis in argon and gasification with O(2) and CO(2) were performed using a thermogravimetric analyzer (TGA) coupled with a Fourier transform infrared (FTIR) spectrometer. The results indicate that although the influence of oxygen and CO(2) in the atmosphere on nitrogen behavior is different for the amino acids, it is interesting to find some phenomenon in common. The presence of oxygen promotes NO and HNCO formation for all the three amino acids; HCN and HNCO formation are suppressed by introduced CO(2) for all the three amino acids. This can reveal the N-conversion mechanism from biomass in depth under the same conditions.

  16. NOx and N2O precursors from biomass pyrolysis: nitrogen transformation from amino acid.

    PubMed

    Ren, Qiangqiang; Zhao, Changsui

    2012-04-01

    Large quantities of NO(x) and N(2)O emissions can be produced from biomass burning. Understanding nitrogen behavior during biomass pyrolysis is crucial. Nitrogen in biomass is mainly in forms of proteins (amino acids). Phenylalanine, aspartic acid, and glutamic acid were used as the model compounds for the nitrogen in biomass. Release behavior tests of nitrogen species from the three amino acids during pyrolysis in argon and gasification with O(2) and CO(2) were performed using a thermogravimetric analyzer (TGA) coupled with a Fourier transform infrared (FTIR) spectrometer. The results indicate that although the influence of oxygen and CO(2) in the atmosphere on nitrogen behavior is different for the amino acids, it is interesting to find some phenomenon in common. The presence of oxygen promotes NO and HNCO formation for all the three amino acids; HCN and HNCO formation are suppressed by introduced CO(2) for all the three amino acids. This can reveal the N-conversion mechanism from biomass in depth under the same conditions. PMID:22439902

  17. Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Liang, Junyi; Qi, Xuan; Souza, Lara; Luo, Yiqi

    2016-05-01

    The nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive research has explored whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in the terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in the plant and litter pools but not in the soil pool, partially supporting one of the basic assumptions in the PNL hypothesis that elevated CO2 results in more N sequestered in organic pools. However, CO2 enrichment significantly increased the N influx via biological N fixation and the loss via N2O emission, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth was observed over time up to the longest experiment of 13 years. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions in spite of the increases in plant N sequestration and N2O emission. Moreover, our syntheses indicate that CO2 enrichment increases soil ammonium (NH4+) to nitrate (NO3-) ratio. The changed NH4+/NO3- ratio and subsequent biological processes may result in changes in soil microenvironments, above-belowground community structures and associated interactions, which could potentially affect the terrestrial biogeochemical cycles. In addition, our data synthesis suggests that more long-term studies, especially in regions other than temperate ones, are needed for comprehensive assessments of the PNL hypothesis.

  18. Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

    DOE PAGES

    Liang, Junyi; Qi, Xuan; Souza, Lara; Luo, Yiqi

    2016-05-10

    The nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive research has explored whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in the terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in the plant and litter pools but not in the soil pool, partially supporting one of themore » basic assumptions in the PNL hypothesis that elevated CO2 results in more N sequestered in organic pools. However, CO2 enrichment significantly increased the N influx via biological N fixation and the loss via N2O emission, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth was observed over time up to the longest experiment of 13 years. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions in spite of the increases in plant N sequestration and N2O emission. Moreover, our syntheses indicate that CO2 enrichment increases soil ammonium (NH4+) to nitrate (NO3−) ratio. The changed NH4+/NO3− ratio and subsequent biological processes may result in changes in soil microenvironments, above-belowground community structures and associated interactions, which could potentially affect the terrestrial biogeochemical cycles. In addition, our data synthesis suggests that more long-term studies, especially in regions other than temperate ones, are needed for comprehensive assessments of the PNL hypothesis.« less

  19. Fate of microbial nitrogen, carbon, hydrolysable amino acids, monosaccharides, and fatty acids in sediment

    NASA Astrophysics Data System (ADS)

    Veuger, Bart; van Oevelen, Dick; Middelburg, Jack J.

    2012-04-01

    The fate of microbial carbon, nitrogen, hydrolysable amino acids (HAAs), monosaccharides, and fatty acids in sediment was investigated experimentally. The microbial community of a tidal flat sediment was labeled with 13C-enriched glucose and 15N-enriched ammonium, and sediment was incubated for up to 371 days. Analysis of total concentrations and 13C- and 15N content of bulk sediment, hydrolysable amino acids (including D-alanine), monosaccharides, total fatty acids (TFAs), and phospholipid-derived fatty acids (PLFAs) allowed us to trace the fate of microbial biomass and -detritus and the major biochemical groups therein (proteins, carbohydrates, and lipids) over intermediate time scales (weeks-months). Moreover, the unidentified fraction of the labeled material (i.e. not analyzed as HAA, FA, or carbohydrate) provided information on the formation and fate of molecularly uncharacterizable organic matter. Loss of 13C and 15N from the sediment was slow (half live of 433 days) which may have been due to the permanently anoxic conditions in the experiment. Loss rates for the different biochemical groups were also low with the following order of loss rate constants: PLFA > TFA > HAA > monosaccharides. The unidentified 13C-pool was rapidly formed (within days) and then decreased relatively slowly, resulting in a gradual relative accumulation of this pool over time. Degradation and microbial reworking of the labeled material resulted in subtle, yet consistent, diagenetic changes within the different biochemical groups. In the HAA pool, glycine, lysine, and proline were lost relatively slowly (i.e. best preserved) while there was no accumulation of D-alanine relative to L-alanine, indicating no relative accumulation of bacterial macromolecules rich in D-alanine. In the fatty acid pool, there was very little difference between PLFAs and TFAs, indicating a very similar lability of these pools. Differences between individual fatty acids included a relatively slow loss of i15

  20. Food contact surfaces coated with nitrogen-doped titanium dioxide: effect on Listeria monocytogenes survival under different light sources

    NASA Astrophysics Data System (ADS)

    Rodrigues, D.; Teixeira, P.; Tavares, C. J.; Azeredo, J.

    2013-04-01

    Improvement of food safety is a very important issue, and is on the basis of production and application of new/modified food contact surfaces. Titanium dioxide (TiO2) and, more recently, nitrogen-doped titanium dioxide (N-TiO2) coatings are among the possible forms to enhance food contact surfaces performance in terms of higher hygiene and easier sanitation. In this context, the present work aimed at evaluating the bactericidal activity of an N-TiO2 coating on glass and stainless steel under two different sources of visible light - fluorescent and incandescent - and ultraviolet (UV) irradiation. Listeria monocytogenes was chosen as representative of major foodborne pathogens and its survival was tested on N-TiO2 coated coupons. In terms of survival percentage, good results were obtained after exposure of coated surfaces to all light types since, apart from the value obtained after exposing glass to fluorescent light (56.3%), survival rates were always below 50%. However, no effective disinfection was obtained, given that for a disinfectant or sanitizing agent to be claimed as effective it needs to be able to promote at least a 3-log reduction of the microbial load, which was not observed for any of the experimental conditions assessed. Even so, UV irradiation was the most successful on eliminating cells on coated surfaces, since the amount of bacteria was reduced to 1.49 × 106 CFU/ml on glass and 2.37 × 107 on stainless steel. In contrast, both visible light sources had only slightly decreased the amount of viable cells, which remained in the range of 8 log CFU/ml. Hence, although some bactericidal effect was accomplished under visible light, UV was the most effective light source on promoting photocatalytic reactions on N-TiO2 coated coupons and none of the experimental conditions have reached a satisfactory disinfection level. Thus, this surface coating needs further research and improvement in order to become truly effective against foodborne pathogens and

  1. The effect of free air carbon dioxide enrichment and nitrogen fertilisation on the chemical composition and nutritional value of wheat and barley grain.

    PubMed

    Wroblewitz, Stefanie; Hüther, Liane; Manderscheid, Remy; Weigel, Hans-Joachim; Wätzig, Hermann; Dänicke, Sven

    2013-08-01

    A rising atmospheric CO2 concentration might influence the nutrient composition of feedstuffs and consequently the nutritional value for livestock. The present study investigates the effects of atmospheric CO2 enrichment on the chemical composition and nutritional value of winter wheat cv. "Batis" and winter barley cv. "Theresa". Both cereals were grown at two different atmospheric CO2 concentrations (ambient CO2 [AMBI]: 380 ppm and enriched CO2 [free air carbon dioxide enrichment, FACE]: 550 ppm) for two growing seasons. The influence of two different nitrogen (N) fertilisation levels (adequate N supply [N100] and nearly 50% of adequate N supply [N50]) were studied as well. A significant effect was observed for the crude protein content, which declined at FACE condition in a range of 8-16 g kg(-1) in wheat and of 10-20 g kg(-1) in barley. A reduced N fertilisation level resulted in a strong reduction of crude protein concentration in both cereal species. In wheat, a decrease in N supply significantly enhanced the concentration of starch and crude fibre. In barley, only the concentration of fructose increased under FACE condition and reduced N fertilisation. The FACE did not have major effects on the concentrations of minerals, while the influence of N fertilisation was different for both cereals. Whereas no effects could be observed for barley, a reduced N supply caused a significant reduction in concentrations of zinc, manganese and iron in wheat. Furthermore, an undirected effect of atmospheric CO2 and N fertilisation levels were found for the amino acid concentrations. Based on these results, future scenarios of climate change would have an impact on the nutritional value of cereal grains.

  2. Carbon dioxide concentration and nitrogen input affect the C and N storage pools in Amanita muscaria-Picea abies mycorrhizae.

    PubMed

    Turnau, K; Berger, A; Loewe, A; Einig, W; Hampp, R; Chalot, M; Dizengremel, P; Kottke, I

    2001-02-01

    We studied the influence of elevated atmospheric CO2 concentration ([CO2]) on the vacuolar storage pool of nitrogen-containing compounds and on the glycogen pool in the hyphal sheath of Amanita muscaria (L. ex Fr.) Hooker-Picea abies L. Karst. mycorrhizae grown with two concentrations of ammonium in the substrate. Mycorrhizal seedlings were grown in petri dishes on agar containing 5.3 or 53 mg N l(-1) and exposed to 350 or 700 microl CO2 l(-1) for 5 or 7 weeks, respectively. Numbers and area of nitrogen-containing bodies in the vacuoles of the mycorrhizal fungus were determined by light microscopy linked to an image analysis system. The relative concentration of nitrogen in the vacuolar bodies was measured by electron energy loss spectroscopy (EELS). Glycogen stored in the cytosol was determined at the ultrastructural level by image analysis after staining the sections (PATAg test). Shoot dry weight, net photosynthesis and relative amounts of N in vacuolar bodies were greater at the higher N and CO2 concentrations. The numbers and areas of vacuolar N-containing bodies were significantly greater at the higher N concentration only at ambient [CO2]. In the same treatment the percentage of hyphae containing glycogen declined to nearly zero. We conclude that, in the high N/low [CO2] treatment, the mycorrhizal fungus had an insufficient carbohydrate supply, partly because of increased amino acid synthesis by the non-mycorrhizal rootlets. When [CO2] was increased, the equilibrium between storage of glycogen and N-containing compounds was reestablished.

  3. Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures.

    PubMed

    Ryalls, James M W; Moore, Ben D; Riegler, Markus; Gherlenda, Andrew N; Johnson, Scott N

    2015-02-01

    Changes in host plant quality, including foliar amino acid concentrations, resulting from global climate change and attack from multiple herbivores, have the potential to modify the pest status of insect herbivores. This study investigated how mechanically simulated root herbivory of lucerne (Medicago sativa) before and after aphid infestation affected the pea aphid (Acyrthosiphon pisum) under elevated temperature (eT) and carbon dioxide concentrations (eCO2). eT increased plant height and biomass, and eCO2 decreased root C:N. Foliar amino acid concentrations and aphid numbers increased in response to eCO2, but only at ambient temperatures, demonstrating the ability of eT to negate the effects of eCO2. Root damage reduced aboveground biomass, height, and root %N, and increased root %C and C:N, most probably via decreased biological nitrogen fixation. Total foliar amino acid concentrations and aphid colonization success were higher in plants with roots cut early (before aphid arrival) than those with roots cut late (after aphid arrival); however, this effect was counteracted by eT. These results demonstrate the importance of amino acid concentrations for aphids and identify individual amino acids as being potential factors underpinning aphid responses to eT, eCO2, and root damage in lucerne. Incorporating trophic complexity and multiple climatic factors into plant-herbivore studies enables greater insight into how plants and insects will interact in the future, with implications for sustainable pest control and future crop security.

  4. Exposures of older adults with chronic respiratory illness to nitrogen dioxide. A combined laboratory and field study

    SciTech Connect

    Hackney, J.D.; Linn, W.S.; Avol, E.L.; Shamoo, D.A.; Anderson, K.R.; Solomon, J.C.; Little, D.E.; Peng, R.C. )

    1992-12-01

    We combined field and laboratory experimentation to evaluate the effects of nitrogen dioxide in a panel of Los Angeles area residents with chronic respiratory illness, 15 men and 11 women aged 47 to 69. All had heavy smoking history, chronic symptoms, and low FEV1; some also had low FVC. During the fall-winter high-NO2 season, they monitored themselves for 2-wk periods using spirometers in the home, passive NO2 sampling badges, and diaries to record time and activity patterns and clinical status. In the middle of each self-monitoring week they were exposed in a chamber, once to clean air and once to 0.3 ppm NO2. Chamber exposures were double blind, lasted 4 h, and included four 7-min exercise sessions with average ventilation rates near 25 L/min. Symptom reports and hourly forced expiratory function tests showed no statistically significant differences between clean air and NO2 chamber exposures, although peak flow showed a approximately 3% loss with NO2 relative to clean air during the first 2 h of exposure only (p = 0.056). No significant overall differences were found between field self-measurements and measurements of lung function in the chamber or between field measurements in clean air and NO2 exposure weeks. Field data showed that group average lung function and symptom levels were worse in the morning than later in the day (p < 0.005) but otherwise were stable over 2 wk. Even though most subjects smoked and stayed indoors 80 to 90% of the time, personal NO2 exposures correlated significantly with outdoor NO2 concentrations as reported by local monitoring stations.

  5. The retrieval of the concentrations of nitric oxide and nitrogen dioxide from satellite solar occultation measurements at sunset and sunrise

    SciTech Connect

    Cartalis, C.I.

    1989-01-01

    HALOE (Halogen Occultation Experiment), scheduled to fly on the Upper Atmosphere Research Satellite (UARS) in 1991, aims to retrieve the vertical concentration profiles of seven minor stratospheric constituents in order to improve the understanding of ozone's photochemistry. This dissertation concentrates on the retrieval of the concentrations of nitric oxide and nitrogen dioxide, which both play an active role in the photochemistry of ozone. The investigation is complicated because of their large diurnal changes which are intensified at sunrise and sunset. Consequently, the retrieval of NO and NO{sub 2} from solar occultation measurements at twilight needs to take into account the lifetimes and the rapid interconversion of NO and NO{sub 2}. If the temporal and spatial variations of NO and NO{sub 2} are neglected, the resulting errors for altitudes less than 20 km reach 100 and 5% respectively and for both sunset and sunrise. A photochemical scheme is developed and a separate code calculates the photodissociation rates of the species involved in photochemical reactions, as a function of latitude, temperature, altitude and season. A retrieval code is developed combining an iterative inversion algorithm, working from top of the atmosphere downwards, and a parameterization of the variability of NO and NO{sub 2}. The method is used to examine the accuracy of the retrieval of the vertical concentration profiles and results show that the recovered profiles are in good agreement with measured ones, reflect the trends of NO and NO{sub 2} at sunset and sunrise and satisfy the accuracy expectations of the HALOE experiment.

  6. Slant column MAX-DOAS measurements of nitrogen dioxide, formaldehyde, glyoxal and oxygen dimer in the urban environment of Athens

    NASA Astrophysics Data System (ADS)

    Gratsea, Myrto; Vrekoussis, Mihalis; Richter, Andreas; Wittrock, Folkard; Schönhardt, Anja; Burrows, John; Kazadzis, Stelios; Mihalopoulos, Nikos; Gerasopoulos, Evangelos

    2016-06-01

    Slant column (SC) densities of nitrogen dioxide (NO2), formaldehyde (HCHO), glyoxal (CHOCHO) and oxygen dimer (O4) were successfully retrieved for the first time in Athens, by using spectral measurements from a ground-based multi-azimuth Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) system. The data span the period from October 2012 to March 2014 and measurements were conducted at NOA's (National Observatory of Athens) station in Penteli (38.0°N, 23.9°E, 527 m a.s.l.) at eight azimuth angles and eight off-axis elevation angles. The SCNO2, SCHCHO and SCCHOCHO measurements at +1ο elevation angle, pointing towards the urban area, range from 0.6 to 24·1016, 0.8-9.6·1016 and 0.3-5.2·1015 molec cm-2 (mean daily values throughout the whole period), respectively. Seasonal modulation characterised by summertime maximum and wintertime minimum was observed for HCHO and CHOCHO, while for NO2 the maximum values were recorded during winter. Changes in the diurnal variability of all trace gases with season and day of the week are investigated suggesting a strong link to primary anthropogenic sources for NO2 and a weaker one, compared to photochemistry, for HCHO and CHOCHO. In addition, the impact of the reduced anthropogenic emissions during weekends on the measured SC values was quantified and 30%-50% lower SCNO2 values were found during weekends. The contribution of local urban emissions to the overall recorded amounts of the selected species was assessed. Using meteorological data from NOA's station in Penteli, the impact of the local circulation patterns on the SC levels was estimated, and a strong relation between western wind direction, which is related to the industrial area, and enhanced SC measurements was found.

  7. Predictors of concentrations of nitrogen dioxide, fine particulate matter, and particle constituents inside of lower socioeconomic status urban homes.

    PubMed

    Baxter, Lisa K; Clougherty, Jane E; Laden, Francine; Levy, Jonathan I

    2007-08-01

    Air pollution exposure patterns may contribute to known spatial patterning of asthma morbidity within urban areas. While studies have evaluated the relationship between traffic and outdoor concentrations, few have considered indoor exposure patterns within low socioeconomic status (SES) urban communities. In this study, part of a prospective birth cohort study assessing asthma etiology in urban Boston, we collected indoor and outdoor 3-4 day samples of nitrogen dioxide (NO2) and fine particulate matter (PM2.5) in 43 residences across multiple seasons from 2003 to 2005. Homes were chosen to represent low SES households, including both cohort and non-cohort residences in similar neighborhoods, and consisted almost entirely of multiunit residences. Reflectance analysis and X-ray fluorescence spectroscopy were performed on the particle filters to determine elemental carbon (EC) and trace element concentrations, respectively. Additionally, information on home characteristics (e.g. type, age, stove fuel) and occupant behaviors (e.g. smoking, cooking, cleaning) were collected via a standardized questionnaire. The contributions of outdoor and indoor sources to indoor concentrations were quantified with regression analyses using mass balance principles. For NO2 and most particle constituents (except outdoor-dominated constituents like sulfur and vanadium), the addition of selected indoor source terms improved the model's predictive power. Cooking time, gas stove usage, occupant density, and humidifiers were identified as important contributors to indoor levels of various pollutants. A comparison between cohort and non-cohort participants provided another means to determine the influence of occupant activity patterns on indoor-outdoor ratios. Although the groups had similar housing characteristics and were located in similar neighborhoods, cohort members had significantly higher indoor concentrations of PM2.5 and NO2, associated with indoor activities. We conclude that the

  8. Impact of emissions and +2 °C climate change upon future ozone and nitrogen dioxide over Europe

    NASA Astrophysics Data System (ADS)

    Watson, Laura; Lacressonnière, Gwendoline; Gauss, Michael; Engardt, Magnuz; Andersson, Camilla; Josse, Béatrice; Marécal, Virginie; Nyiri, Agnes; Sobolowski, Stefan; Siour, Guillaume; Szopa, Sophie; Vautard, Robert

    2016-10-01

    The evolution of ozone and nitrogen dioxide over Europe between the present day and a future period with a +2 °C global warming relative to the pre-industrial climate was studied using four offline chemistry transport models, each driven by a different climate model. Given the recent outcome of the COP21 negotiations, understanding the implications of climate change around the +2 °C threshold has never been more pressing or relevant. One of the objectives of this study was to show how changes in anthropogenic emissions and +2 °C climate change are expected to affect future air quality, which may have important implications upon human health. It was found that a +2 °C climate change alone was responsible for a modest, and not statistically significant, increase in surface O3 concentrations (of between -0.1-0.8 ppb in the summer averaged over the European domain) compared to the present climate. Two different emission scenarios were used for the future time period in order to provide an estimate of the extent of air pollution reductions that could occur if (a) all currently planned air quality legislation is implemented and (b) all maximum technologically feasible emission reductions are implemented. The results showed that summer O3 could be reduced by between 4 and 5 ppb under a current legislation scenario, with at least 3 ppb of further reductions under the maximum mitigated scenario. Calculations of summer ozone enhancement were used as a metric to analyse the results after having removed background ozone level changes. In conclusion it was found that future air quality on a regional scale will depend upon the implementation of effective emission reduction policy; the positive effects of which should not be hindered by a +2 °C global warming.

  9. Data assimilation of satellite-retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS

    NASA Astrophysics Data System (ADS)

    Inness, A.; Blechschmidt, A.-M.; Bouarar, I.; Chabrillat, S.; Crepulja, M.; Engelen, R. J.; Eskes, H.; Flemming, J.; Gaudel, A.; Hendrick, F.; Huijnen, V.; Jones, L.; Kapsomenakis, J.; Katragkou, E.; Keppens, A.; Langerock, B.; de Maziere, M.; Melas, D.; Parrington, M.; Peuch, V. H.; Razinger, M.; Richter, A.; Schultz, M. G.; Suttie, M.; Thouret, V.; Vrekoussis, M.; Wagner, A.; Zerefos, C.

    2015-05-01

    Daily global analyses and 5-day forecasts are generated in the context of the European Monitoring Atmospheric Composition and Climate (MACC) project using an extended version of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The IFS now includes modules for chemistry, deposition and emission of reactive gases, aerosols, and greenhouse gases, and the 4-dimensional variational data assimilation scheme makes use of multiple satellite observations of atmospheric composition in addition to meteorological observations. This paper describes the data assimilation setup of the new Composition-IFS (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation. The largest improvement in CO by assimilation of Measurements of Pollution in the Troposphere (MOPITT) CO columns is seen in the lower troposphere of the Northern Hemisphere (NH) extratropics during winter, and during the South African biomass-burning season. The assimilation of several O3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O3 analysis fields relative to the control run. The impact on lower tropospheric ozone, which comes from the residual of the total column and stratospheric profile O3 data, is smaller, but nevertheless there is some improvement particularly in the NH during winter and spring. The impact of the assimilation of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) is small because of the short lifetime of NO2, suggesting that NO2 observations would be better used to adjust emissions instead of initial conditions. The results further indicate that the quality of the tropospheric analyses and of the stratospheric ozone analysis obtained with the C-IFS system has improved compared to

  10. Stratospheric ozone and nitrogen dioxide total column and vertical profiles in southern Portugal during 2004-2007

    NASA Astrophysics Data System (ADS)

    Bortoli, D.; Silva, A. M.; Roselli, D.; Giovanelli, G.

    2007-10-01

    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed by the collaboration between CGE-UE, ISAC-CNR and ENEA. SPATRAM is a multi-purpose UV-Vis-NIR spectrometer (250-950 nm). It is installed at the Observatory of the CGE since April 2004 and actually it is utilized to carry-out measurements of the zenith scattered radiation, the so-called "Passive mode", in order to retrieve-by application of DOAS (Differential Optical Absorption Spectroscopy) methodology-the vertical content of some atmospheric tracers such as Ozone (O3) and Nitrogen Dioxide (NO2). For the continuous NO2 monitoring the 425-455 nm spectral region is investigated. For the Ozone retrieval the spectral interval 320-340 nm is chosen. In this study, after a brief description of the instrument, a short explanation of the DOAS methodology and of the inversion algorithms used for the determination of the vertical distribution of the some atmospheric compounds are provided. The obtained results in terms of diurnal and seasonal variation of O3 and NO2 total column are presented. The measurements are in good agreement with the photochemical theory of NO2 and O3, showing the maximum values during the summer season and the minimum during the winter. In addition the application, to the output of the DOAS program, of sophisticated inversion schemes, using the Air Mass Factor (AMF) matrix as the kernel of the inversion algorithm, allowed for the determination of vertical distribution of some atmospheric tracers. The results obtained for NO2 and O3 are presented and discussed.

  11. Predictors of concentrations of nitrogen dioxide, fine particulate matter, and particle constituents inside of lower socioeconomic status urban homes.

    PubMed

    Baxter, Lisa K; Clougherty, Jane E; Laden, Francine; Levy, Jonathan I

    2007-08-01

    Air pollution exposure patterns may contribute to known spatial patterning of asthma morbidity within urban areas. While studies have evaluated the relationship between traffic and outdoor concentrations, few have considered indoor exposure patterns within low socioeconomic status (SES) urban communities. In this study, part of a prospective birth cohort study assessing asthma etiology in urban Boston, we collected indoor and outdoor 3-4 day samples of nitrogen dioxide (NO2) and fine particulate matter (PM2.5) in 43 residences across multiple seasons from 2003 to 2005. Homes were chosen to represent low SES households, including both cohort and non-cohort residences in similar neighborhoods, and consisted almost entirely of multiunit residences. Reflectance analysis and X-ray fluorescence spectroscopy were performed on the particle filters to determine elemental carbon (EC) and trace element concentrations, respectively. Additionally, information on home characteristics (e.g. type, age, stove fuel) and occupant behaviors (e.g. smoking, cooking, cleaning) were collected via a standardized questionnaire. The contributions of outdoor and indoor sources to indoor concentrations were quantified with regression analyses using mass balance principles. For NO2 and most particle constituents (except outdoor-dominated constituents like sulfur and vanadium), the addition of selected indoor source terms improved the model's predictive power. Cooking time, gas stove usage, occupant density, and humidifiers were identified as important contributors to indoor levels of various pollutants. A comparison between cohort and non-cohort participants provided another means to determine the influence of occupant activity patterns on indoor-outdoor ratios. Although the groups had similar housing characteristics and were located in similar neighborhoods, cohort members had significantly higher indoor concentrations of PM2.5 and NO2, associated with indoor activities. We conclude that the

  12. Association of short-term exposure to fine particulate matter and nitrogen dioxide with acute cardiovascular effects.

    PubMed

    Wu, Chang-Fu; Shen, Fu-Hui; Li, Ya-Ru; Tsao, Tsung-Ming; Tsai, Ming-Jer; Chen, Chu-Chih; Hwang, Jing-Shiang; Hsu, Sandy Huey-Jen; Chao, Hsing; Chuang, Kai-Jen; Chou, Charles C K; Wang, Ya-Nan; Ho, Chi-Chang; Su, Ta-Chen

    2016-11-01

    This study evaluated whether exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) is associated with cardiovascular effects by examining a panel of 89 healthy subjects in Taipei, Taiwan. The subjects received two health examinations approximately 8months apart in 2013. Brachial-ankle pulse wave velocity (baPWV), a physiological indicator of arterial stiffness, and high-sensitivity C-reactive protein (hsCRP), a biomarker of vascular inflammations, were measured during each examination. Two exposure assessment methods were used for estimating the subjects' exposure to PM2.5 and NO2. The first method involved constructing daily land use regression (LUR) models according to measurements collected at ambient air quality monitoring stations. The second method required combining the LUR estimates with indoor monitoring data at the workplace of the subjects. Linear mixed models were used to examine the association between the exposure estimates and health outcomes. The results showed that a 10-μg/m(3) increase in PM2.5 concentration at a 1-day lag was associated with 2.1% (95% confidence interval: 0.7%-3.6%) and 2.4% (0.8%-4.0%) increases in baPWV based on the two exposure assessment methods, whereas no significant association was observed for NO2. The significant effects of PM2.5 remained in the two-pollutant models. By contrast, NO2, but not PM2.5, was significantly associated with increased hsCRP levels (16.0%-37.3% in single-pollutant models and 26.4%-44.6% in two-pollutant models, per 10-ppb increase in NO2). In conclusion, arterial stiffness might be more sensitive to short-term PM2.5 exposure than is inflammation. PMID:27344119

  13. EOS7C Version 1.0 TOUGH2 Module for Carbon Dioxide or Nitrogen in Natural Gas

    2008-01-11

    EOS7C is a TOUGH2 module for multicomponent gas mixtures in the systems methane-carbon dioxide (CH{sub 4}-CO{sub 2}) or methane-nitrogen (CH{sub 4}-N{sub 2}) with or without an aqueous phase and H{sub 2}O vapor. EOS7C uses a cubic equation of state and an accurate solubility formulation along with a multiphase Darcy's Law to model flow and transport of gas and aqueous phase mixtures over a wide range of pressures and temperatures appropriate to subsurface geologic carbon sequestrationmore » sites and natural gas reservoirs. EOS7C models supercritical CO{sub 2{ and subcritical CO{sub 2} as a non-condensible gas, hence EOS7C does not model the transitions to liquid or solid CO{sub 2} conditions. The components modeled in EOS7C are water, brine, non-condensible gas, gas tracer, methane, and optional heat. The non-condensible gas (NCG) can be selected by the user to be CO{sub 2} or N{sub 2}. The real gas properties module has options for Peng-Robinson, Redlich-Kwong, or Soave-Redlich-Kwong equations of state to calculate gas mixture density, enthalpy departure, and viscosity. Partitioning of the NCG and CH{sub 4} between the aqueous and gas phases is calculated using a very accurate chemical equilibrium approach. Transport of the gaseous and dissolved components is by advection and Fickian molecular diffusion. EOS7C is written in FORTAN77.« less

  14. Tropospheric ozone and nitrogen dioxide measurements in urban and rural regions as seen by IASI and GOME-2

    NASA Astrophysics Data System (ADS)

    Safieddine, S.; Clerbaux, C.; George, M.; Hadji-Lazaro, J.; Hurtmans, D.; Coheur, P.; Wespes, C.; Layola, D.; Valks, P.; Hao, N.

    2013-05-01

    Tropospheric ozone (O3) columns in urban and rural regions as seen by the infrared sounder IASI are analyzed along with GOME-2 tropospheric nitrogen dioxide (NO2) columns. Results over nine cities of the Northern Hemisphere for the period 2008-2011 show a typical seasonal behavior of tropospheric O3, with a first maximum reached in late spring because of stratospheric intrusion mainly, and a continuous rise till the summer because of the anthropogenic based ozone production. Over the East Asian cities, a decrease in the O3 tropospheric column is detected during monsoon period. Seasonal cycling of tropospheric NO2 shows consistent higher values during winter because of the higher anthropogenic sources and longer lifetime. In rural regions, a complex relation between the O3 and NO2 column is found, with higher linearity in summer. O3 concentrations in rural sites are found to be comparable to those found closest to the anthropogenic emission sources, with peak values in spring and summer. Furthermore, the effect of the reduction of pollutant emissions in China during the Olympic games of 2008 is studied. GOME-2 NO2 measurements show a reduction up to 54% above Beijing during this period compared to the following three years. IASI O3 measurements show an increase of 12% during July 2008 followed by a decrease of 5-6% during the months of August and September. A significant reduction in O3 tropospheric column values is also detected in the area downwind, few hundreds of kilometers to the south of Beijing.

  15. Photocatalytic oxidation of VOC, nitrogen oxide and atrazine using titanium dioxide modified with perovskite materials

    NASA Astrophysics Data System (ADS)

    Vajifdar, Kayzad Jimmy

    Photocatalysis utilizes near-UV or visible light to break down organic pollutants into innocuous compounds at room temperatures and has gained much attention in air and water pollution control. Chapter 1 introduces the use of semiconducting optical crystals as an additive to a photocatalyst. The perovskite optical material BaTiO3 (band gap of 3.7-3.8 eV) is found to increase VOC destruction when black light is used. The best composition found is 0.1 wt% BaTiO3 with the balance being TiO2. This photocatalyst increases perchloroethylene (PCE) conversion by 12% to 32% for space times between 1.4 and 17.2 seconds and inlet concentrations of 40 to 130 ppm with a 4 W black light. The average enhancement is approximately 25%. For butyraldehyde conversion the maximum enhancement is 20% at 130 ppm in 3.6 seconds. The UV/Vis spectroscopy data indicate a lower absorbance with the additive. The reaction parameters studied are space velocity, inlet concentration and light source. Oxidation by-products are identified using a GCMS. Chapter 2 introduces photocatalysis as an emerging green technology for environmental protection to oxidize NOx. The experimental results indicate that the coating of photocatalytic materials on concrete pavements can harvest the light energy for NOx pollution control. The photocatalytic coating has the potential to reduce NOx concentration in the atmosphere economically, nearly maintenance-free. NOx will be oxidized to nitric acid, neutralized by the alkaline base materials in concrete, and washed away by rain. The reduction in the number of high ozone days can be significant to allow sustainable economic developments in the many ozone-non-attainment areas worldwide. One of the foci will be pavement coated with photocatalysts enhanced with perovskites/ferroelectric optical crystals such as BaTiO3 via increased transmission/scattering and electron-hole pair stabilization. The developed technology can be transferred to the cement and coating industries

  16. Chemical and biological consequences of using carbon dioxide versus acid additions in ocean acidification experiments

    USGS Publications Warehouse

    Yates, Kimberly K.; DuFore, Christopher M.; Robbins, Lisa L.

    2013-01-01

    Use of different approaches for manipulating seawater chemistry during ocean acidification experiments has confounded comparison of results from various experimental studies. Some of these discrepancies have been attributed to whether addition of acid (such as hydrochloric acid, HCl) or carbon dioxide (CO2) gas has been used to adjust carbonate system parameters. Experimental simulations of carbonate system parameter scenarios for the years 1766, 2007, and 2100 were performed using the carbonate speciation program CO2SYS to demonstrate the variation in seawater chemistry that can result from use of these approaches. Results showed that carbonate system parameters were 3 percent and 8 percent lower than target values in closed-system acid additions, and 1 percent and 5 percent higher in closed-system CO2 additions for the 2007 and 2100 simulations, respectively. Open-system simulations showed that carbonate system parameters can deviate by up to 52 percent to 70 percent from target values in both acid addition and CO2 addition experiments. Results from simulations for the year 2100 were applied to empirically derived equations that relate biogenic calcification to carbonate system parameters for calcifying marine organisms including coccolithophores, corals, and foraminifera. Calculated calcification rates for coccolithophores, corals, and foraminifera differed from rates at target conditions by 0.5 percent to 2.5 percent in closed-system CO2 gas additions, from 0.8 percent to 15 percent in the closed-system acid additions, from 4.8 percent to 94 percent in open-system acid additions, and from 7 percent to 142 percent in open-system CO2 additions.

  17. Snails from heavy-metal polluted environments have reduced sensitivity to carbon dioxide-induced acidity.

    PubMed

    Lefcort, Hugh; Cleary, David A; Marble, Aaron M; Phillips, Morgan V; Stoddard, Timothy J; Tuthill, Lara M; Winslow, James R

    2015-01-01

    Anthropogenic atmospheric CO2 reacts with water to form carbonic acid (H2CO3) which increases water acidity. While marine acidification has received recent consideration, less attention has been paid to the effects of atmospheric carbon dioxide on freshwater systems-systems that often have low buffering potential. Since many aquatic systems are already impacted by pollutants such as heavy metals, we wondered about the added effect of rising atmospheric CO2 on freshwater organisms. We studied aquatic pulmonate snails (Physella columbiana) from both a heavy-metal polluted watershed and snails from a reference watershed that has not experienced mining pollution. We used gaseous CO2 to increase water acidity and we then measured changes in antipredatory behavior and also survival. We predicted a simple negative additive effect of low pH. We hypothesized that snails from metal-polluted environments would be physiologically stressed and impaired due to defense responses against heavy metals. Instead, snails from populations that acclimated or evolved in the presence of heavy metal mining pollution were more robust to acidic conditions than were snails from reference habitats. Snails from mining polluted sites seemed to be preadapted to a low pH environment. Their short-term survival in acidic conditions was better than snails from reference sites that lacked metal pollution. In fact, the 48 h survival of snails from polluted sites was so high that it did not significantly differ from the 24 h survival of snails from control sites. This suggests that the response of organisms to a world with rising anthropogenic carbon dioxide levels may be complex and difficult to predict. Snails had a weaker behavioral response to stressful stimuli if kept for 1 month at a pH that differed from their lake of origin. We found that snails raised at a pH of 5.5 had a weaker response (less of a decrease in activity) to concentrated heavy metals than did snails raised at their natal pH of

  18. Snails from heavy-metal polluted environments have reduced sensitivity to carbon dioxide-induced acidity.

    PubMed

    Lefcort, Hugh; Cleary, David A; Marble, Aaron M; Phillips, Morgan V; Stoddard, Timothy J; Tuthill, Lara M; Winslow, James R

    2015-01-01

    Anthropogenic atmospheric CO2 reacts with water to form carbonic acid (H2CO3) which increases water acidity. While marine acidification has received recent consideration, less attention has been paid to the effects of atmospheric carbon dioxide on freshwater systems-systems that often have low buffering potential. Since many aquatic systems are already impacted by pollutants such as heavy metals, we wondered about the added effect of rising atmospheric CO2 on freshwater organisms. We studied aquatic pulmonate snails (Physella columbiana) from both a heavy-metal polluted watershed and snails from a reference watershed that has not experienced mining pollution. We used gaseous CO2 to increase water acidity and we then measured changes in antipredatory behavior and also survival. We predicted a simple negative additive effect of low pH. We hypothesized that snails from metal-polluted environments would be physiologically stressed and impaired due to defense responses against heavy metals. Instead, snails from populations that acclimated or evolved in the presence of heavy metal mining pollution were more robust to acidic conditions than were snails from reference habitats. Snails from mining polluted sites seemed to be preadapted to a low pH environment. Their short-term survival in acidic conditions was better than snails from reference sites that lacked metal pollution. In fact, the 48 h survival of snails from polluted sites was so high that it did not significantly differ from the 24 h survival of snails from control sites. This suggests that the response of organisms to a world with rising anthropogenic carbon dioxide levels may be complex and difficult to predict. Snails had a weaker behavioral response to stressful stimuli if kept for 1 month at a pH that differed from their lake of origin. We found that snails raised at a pH of 5.5 had a weaker response (less of a decrease in activity) to concentrated heavy metals than did snails raised at their natal pH of

  19. Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium.

    PubMed

    Salimi, Kouroush; Yilmaz, Mehmet; Rzayev, Zakir M O; Piskin, Erhan

    2014-12-19

    This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications.

  20. Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium.

    PubMed

    Salimi, Kouroush; Yilmaz, Mehmet; Rzayev, Zakir M O; Piskin, Erhan

    2014-12-19

    This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications. PMID:25263875

  1. Nitrogen

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, ammonia was produced by 15 companies at 26 plants in 16 states in the United States. Of the total ammonia production capacity, 55% was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas. US producers operated at 66% of their rated capacity. In descending order, Koch Nitrogen, Terra Industries, CF Industries, Agrium and PCS Nitrogen accounted for 81% of the US ammonia production capacity.

  2. Stable nitrogen isotopes in essential versus non-essential amino acids of different plankton size fractions.

    PubMed

    Loick, Natalie; Gehre, Matthias; Voss, Maren

    2007-12-01

    The stable nitrogen isotope values (delta(15)N) of the essential amino acid (EAA) leucine and the delta(15)N values of six non-essential amino acids (NEAAs) from plankton size fractions from the South China Sea (SCS) were analysed. Data from the SCS were collected during two cruises in July 2003 and 2004 onboard of RV Nghien Cuu Bien. The delta(15)N values of alanine, aspartic acid, glutamic acid and leucine increased with size at all sites. The delta(15)N of glycine did not increase with size, the delta(15)N of tyrosine increased with size only at offshore stations and the delta(15)N of proline increased with size only at inshore stations. We found highly significant correlations between the delta(15)N ratios of leucine to the delta(15)N ratios of glutamic acid, proline, alanine, tyrosine and aspartic acid at oligotrophic sites of enhanced nitrogen fixation. In contrast thereto these correlations were less distinct or absent at more eutrophic sites of low nitrogen fixation. A comparison with an independent data set from the tropical North Atlantic revealed intriguing similar patterns. We interpret these patterns as result of the connected metabolism of EAA and NEAA in zooplankton at sites of nitrogen limitation.

  3. Nitrogen mineralization rates of the acidic, xeric soils of the New Jersey Pinelands: laboratory studies

    SciTech Connect

    Poovarodom, S.; Tate, R.L. III

    1988-05-01

    In a series of laboratory incubation studies, the authors evaluated the effects of temperature, moisture, and nitrogen amendment on nitrogen mineralization rates in the acidic Lakehurst and Atsion sands of the New Jersey Pinelands. The average potentially mineralizable nitrogen (N/sub 0/) values for the Lakehurst and Atsion sands were 87 and 94 ..mu..g/g, respectively. Mineralization constants (k) were 0.0501 and 0.0756/wk at 25 and 35/degrees/C, respectively, for the Lakehurst sand and were 0.0327 and 0.0452/wk for the Atsion sand. Maximum mineralization occurred at 35/degrees/C for both soils with Q/sub 10/ values ranging from 1.8 to 2.1. Optimal soil moisture tensions for nitrogen mineralization were between /minus/0.01 and /minus/0.03 MPa. A soil moisture tension of /minus/0.01 MPa reduced nitrogen mineralization with the Lakehurst sand, but not with the Atsion sand. Amendment of the soil with ammonium sulfate increased mineralization with the Atsion sand, but had no effect on the Lakehurst soil. Conversely, ammonium chloride amendment increased the nitrogen mineralization rates in the Lakehurst, but not the Atsion sand. Urea amendment inhibited nitrogen mineralization with both soils. No nitrate accumulation was observed in any of the nitrogen-amended samples.

  4. Carotenoid and fatty acid metabolism in nitrogen-starved Dunaliella salina, a unicellular green microalga.

    PubMed

    Lamers, Packo P; Janssen, Marcel; De Vos, Ric C H; Bino, Raoul J; Wijffels, René H

    2012-11-30

    Nitrogen availability and light intensity affect β-carotene overproduction in the green alga Dunaliella salina. Following a previous study on high-light stress, we here report on the effect of nitrogen depletion on the growth characteristics and β-carotene as well as fatty acid metabolism of D. salina under a constant light regime in a turbidostat. Upon nitrogen depletion, the biomass yield on absorbed light approximately doubled, due to a transient increase in cell division rate, swelling of the cells and a linear increase of the density of the cells. Simultaneously, β-carotene started to accumulate up to a final intracellular concentration of 14 mg LCV⁻¹ (i.e. 2.7% of AFDW). This β-carotene production accounted for 6% of the increased density of the cells, indicating that other biochemical constituents accumulated as well. Since D. salina accumulates β-carotene in lipid globules, we also determined the fatty acid content and composition of D. salina. The intracellular concentration of the total fatty acid pool did not change significantly during nitrogen starvation, indicating that β-carotene and total fatty acid accumulation were unrelated, similar to what was found previously for high-light treated cells. However, for both high-light and nitrogen stress, β-carotene accumulation negatively correlated with the degree of unsaturation of the total fatty acid pool and, within the individual fatty acids, correlated positively with oleic acid biosynthesis, suggesting that oleic acid may be a key component of the lipid-globule-localized triacylglycerols and thereby in β-carotene accumulation.

  5. Carbon dioxide generated from carbonates and acids for sampling blood-feeding arthropods.

    PubMed

    Burkett-Cadena, Nathan D; Blosser, Erik M; Young, Ryan M; Toé, Laurent D; Unnasch, Thomas R

    2015-09-01

    Carbon dioxide (CO2) is utilized to attract mosquitoes and other blood-feeding arthropods to traps around the world. Commercial forms of CO2 (e.g., dry ice and compressed gas) are often unavailable or extremely expensive in developing nations, where vector surveillance is essential to make life-saving decisions. We developed and tested inexpensive and reproducible methods of CO2 production from the combination of acids and carbonates, ranging from very basic (crushed seashells and vinegar) to relatively elaborate (a device that controls the timing of the acid-carbonate reaction and extends the reaction over several hours). When utilized with mosquito traps in Florida, USA and black fly traps in Region des Cascades, Burkina Faso, these carbonate-acid CO2 sources attracted significantly greater numbers of both vector groups, than did unbaited traps. CO2 was generated for more than four hours at levels sufficient to attract vectors over the entire period. The utility of this simple methodology in developing nations should be further evaluated.

  6. Carbon dioxide generated from carbonates and acids for sampling blood-feeding arthropods.

    PubMed

    Burkett-Cadena, Nathan D; Blosser, Erik M; Young, Ryan M; Toé, Laurent D; Unnasch, Thomas R

    2015-09-01

    Carbon dioxide (CO2) is utilized to attract mosquitoes and other blood-feeding arthropods to traps around the world. Commercial forms of CO2 (e.g., dry ice and compressed gas) are often unavailable or extremely expensive in developing nations, where vector surveillance is essential to make life-saving decisions. We developed and tested inexpensive and reproducible methods of CO2 production from the combination of acids and carbonates, ranging from very basic (crushed seashells and vinegar) to relatively elaborate (a device that controls the timing of the acid-carbonate reaction and extends the reaction over several hours). When utilized with mosquito traps in Florida, USA and black fly traps in Region des Cascades, Burkina Faso, these carbonate-acid CO2 sources attracted significantly greater numbers of both vector groups, than did unbaited traps. CO2 was generated for more than four hours at levels sufficient to attract vectors over the entire period. The utility of this simple methodology in developing nations should be further evaluated. PMID:26103427

  7. Field assessment of yeast- and oxalic Acid-generated carbon dioxide for mosquito surveillance.

    PubMed

    Harwood, James F; Richardson, Alec G; Wright, Jennifer A; Obenauer, Peter J

    2014-12-01

    Carbon dioxide (CO2) sources improve the efficacy of mosquito traps. However, traditional CO2 sources (dry ice or compressed gas) may be difficult to acquire for vector surveillance during military contingency operations. For this reason, a new and convenient source of CO2 is required. Two novel CO2 generators were evaluated in order to address this capability gap: 1) an electrolyzer that converts solid oxalic acid into CO2 gas, and 2) CO2 produced by yeast as it metabolizes sugar. The flow rate and CO2 concentration produced by each generator were measured, and each generator's ability to attract mosquitoes to BG-Sentinel™ traps during day surveillance and to Centers for Disease Control and Prevention light traps with incandescent bulbs during night surveillance was compared to dry ice and compressed gas in Jacksonville, FL. The electrolyzed oxalic acid only slightly increased the number of mosquitoes captured compared to unbaited traps. Based on the modest increase in mosquito collection for traps paired with the oxalic acid, it is not a suitable stand-in for either of the 2 traditional CO2 sources. Conversely, the yeast-generated CO2 resulted in collections with mosquito abundance and species richness more closely resembling those of the traditional CO2 sources, despite achieving a lower CO2 flow rate. Therefore, if dry ice or compressed gas cannot be acquired for vector surveillance, yeast-generated CO2 can significantly improve trap capability. PMID:25843133

  8. Lewis acid catalyzed ring-opening polymerization of natural epoxy oil (Euphorbia oil) in carbon dioxide media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an attempt to build up useful application of plant oil based polymers, natural epoxy oil (euphorbia oil-EuO) was polymerized in liquid carbon dioxide in the presence of Lewis acid catalyst [Boron trifluoride diethyl etherate (BF3•OEt2)]. The resulting polymers (RPEuO) were characterized by FTIR ...

  9. Artificial photosynthesis of. beta. -ketocarboxylic acids from carbon dioxide and ketones via enolate complexes of aluminum porphyrin

    SciTech Connect

    Hirai, Yasuhiro; Aida, Takuzo; Inoue, Shohei )

    1989-04-12

    Photochemical fixation of carbon dioxide is of much interest in connection with biological photosynthesis by green plants as well as from the viewpoint of carbon resource utilization. One of the important steps in the assimilation of carbon dioxide is the carboxylation of a carbonyl compound into ketocarboxylic acid, where the reaction proceeds via an enolate species as reactive intermediate. For example, in four carbon (C{sub 4}) pathway and Crassulacean acid metabolism (CAM) processes, pyruvate is converted with the aid of ATP into phosphoenolpyruvate, which is subsequently carboxylated to give oxaloacetate by the action of pyruvate carboxylase. In relation to this interesting biological process, some artificial systems have been exploited for the synthesis of {beta}-ketocarboxylic acid derivatives from carbon dioxide and ketones using nucleophiles such as metal carbonates, thiazolates, phenolates, alkoxides, and strong organic as well as inorganic basis, which promote the enolization of ketones in the intermediate step. We wish to report here a novel, visible light-induced fixation of carbon dioxide with the enolate complex of aluminum porphyrin, giving {beta}-ketocarboxylic acid under mild conditions.

  10. Tropospheric cycle of nitrous acid

    NASA Astrophysics Data System (ADS)

    Harrison, Roy M.; Peak, John D.; Collins, Gareth M.

    1996-06-01

    Measurements of the land surface exchange of nitrous acid over grass and sugar beet surfaces reveal both upward and downward fluxes with flux reversal occurring at an ambient concentration of nitrogen dioxide of about 10 ppb. This confirms earlier preliminary findings and strengthens the hypothesis that substantial production of nitrous acid can occur on land surfaces from reaction of nitrogen dioxide and water vapor. Detailed measurements of nitrous acid have been made in central urban, suburban, and rural environments. These measurements, in conjunction with a simple box model, indicate that the atmospheric concentrations of nitrous acid are explicable in terms of a small number of basic processes in which the most important are the surface production of nitrous acid from nitrogen dioxide, atmospheric production from the NO-OH reaction and loss of nitrous acid by photolysis and dry deposition. In the suburban atmosphere, concentrations of nitrous acid are strongly correlated with nitrogen dioxide. In the rural atmosphere a different behavior is seen, with much higher nitrous acid to nitrogen dioxide ratios occurring in more polluted air with nitrogen dioxide concentrations in excess of 10 ppb. At lower nitrogen dioxide concentrations, net deposition of nitrous acid at the ground leads to very low concentrations in advected air. The model study indicates that during daytime in the suburban atmosphere, production of HONO from the NO-OH reaction can compete with photolysis giving a HONO concentration of a few tenths of a part per billion. At the highest observed daytime concentrations of HONO, production of OH radical from its photolysis can proceed at a rate more than 10 times faster than from photolysis of ozone.

  11. Infrared Spectroscopic Evidence of Surface Speciation of Amino Acids on Titanium Dioxide

    NASA Astrophysics Data System (ADS)

    Jonsson, C. M.; Jonsson, C. L.; Parikh, S. J.; Sverjensky, D. A.; Cleaves, H. J.; Hazen, R. M.

    2008-12-01

    Interactions that occur at the interface between molecules and mineral surfaces in the presence of water are integral to many chemical and physical processes, including the behavior of pollutants in the environment, metal implants in the human body, and perhaps the origin of life. During the emergence of life, mineral surfaces may have played a role in the selection of amino acids, leading to the formation of proteins that are essential building blocks of life. To investigate this hypothesis, we are studying two amino acids, glutamic (Glu) and aspartic (Asp) acid, and their adsorption to the rutile form of titanium dioxide as a function of pH and surface coverage in electrolyte solutions. The objective is to get a fundamental understanding of the speciation and coordination chemistry of these amino acids at the rutile surface. We used attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy to investigate the adsorption of Glu on rutile, and a previously published ATR-FTIR study [1] of Asp and Glu adsorption on an amorphous titanium dioxide film was used as a guide to peak assignment and interpretation of our FTIR spectra. Binding of Glu to both surfaces occurs primarily through one or both of the carboxyl groups, implying that at least two types of surface complexes are formed in a proportion presumably dependent on surface coverage and pH. The interpretation of our results suggests that Glu binds to rutile in a mixed chelating-monodentate fashion involving both carboxyl groups (Glu lying down at the surface), and in a chelating fashion involving only the gamma carboxyl group (Glu standing up at the surface). FTIR results also show that the intensity of the amine peak increases with sorption, which is possibly a consequence of the amine group being brought closer to the surface but not binding directly to it. Glu adsorption on rutile is favored at low pH, based on results from batch adsorption experiments. We have commenced a systematic

  12. Nitrogen dioxide and ultrafine particles dominate the biological effects of inhaled diesel exhaust treated by a catalyzed diesel particulate filter.

    PubMed

    Karthikeyan, Subramanian; Thomson, Errol M; Kumarathasan, Prem; Guénette, Josée; Rosenblatt, Debbie; Chan, Tak; Rideout, Greg; Vincent, Renaud

    2013-10-01

    We studied the impact of a catalyzed diesel particulate filter (DPF) on the toxicity of diesel exhaust. Rats inhaled exhaust from a Cummins ISM heavy-duty diesel engine, with and without DPF after-treatment, or HEPA-filtered air for 4h, on 1 day (single exposure) and 3 days (repeated exposures). Biological effects were assessed after 2h (single exposure) and 20h (single and repeated exposures) recovery in clean air. Concentrations of pollutants were (1) untreated exhaust (-DPF), nitric oxide (NO), 43 ppm; nitrogen dioxide (NO2), 4 ppm; carbon monoxide (CO), 6 ppm; hydrocarbons, 11 ppm; particles, 3.2×10(5)/cm(3), 60-70nm mode, 269 μg/m(3); (2) treated exhaust (+DPF), NO, 20 ppm; NO2, 16 ppm; CO, 1 ppm; hydrocarbons, 3 ppm; and particles, 4.4×10(5)/cm(3), 7-8nm mode, 2 μg/m(3). Single exposures to -DPF exhaust resulted in increased neutrophils, total protein and the cytokines, growth-related oncogene/keratinocyte chemoattractant, macrophage inflammatory protein-1α, and monocyte chemoattractant protein-1 in lung lavage fluid, as well as increased gene expression of interleukin-6, prostaglandin-endoperoxide synthase 2, metallothionein 2A, tumor necrosis factor-α, inducible nitric oxide synthase, glutathione S-transferase A1, heme oxygenase-1, superoxide dismutase 2, endothelin-1 (ET-1), and endothelin-converting enzyme-1 in the lung, and ET- 1 in the heart. Ratio of bigET-1 to ET-1 peptide increased in plasma in conjunction with a decrease in endothelial nitric oxide synthase gene expression in the lungs after exposure to diesel exhaust, suggesting endothelial dysfunction. Rather than reducing toxicity, +DPF exhaust resulted in heightened injury and inflammation, consistent with the 4-fold increase in NO2 concentration. The ratio of bigET-1 to ET-1 was similarly elevated after -DPF and +DPF exhaust exposures. Endothelial dysfunction, thus, appeared related to particle number deposited, rather than particle mass or NO2 concentration. The potential benefits of

  13. Social factors associated with nitrogen dioxide (NO2) exposure during pregnancy: the INMA-Valencia project in Spain.

    PubMed

    Llop, Sabrina; Ballester, Ferran; Estarlich, Marisa; Iñiguez, Carmen; Ramón, Rosa; Gonzalez, Ma Carmen; Murcia, Mario; Esplugues, Ana; Rebagliato, Marisa

    2011-03-01

    Numerous studies have focused on the effects of exposure to air pollution on health; however, certain subsets of the population tend to be more exposed to such pollutants depending on their social or demographic characteristics. In addition, exposure to toxicants during pregnancy may play a deleterious role in fetal development as fetuses are especially vulnerable to external insults. The present study was carried out within the framework of the INMA (Infancia y Medio Ambiente or Childhood and the Environment) multicenter cohort study with the objective of identifying the social, demographic, and life-style factors associated with nitrogen dioxide (NO(2)) exposure in the subjects in the cohort. The study comprised 785 pregnant women who formed part of the INMA cohort in Valencia, Spain. Outdoor levels of NO(2) were measured at 93 sampling sites spread over the study area during four different sampling periods lasting 7 days each. Multiple regression models were used for mapping outdoor NO(2) throughout the area. Individual exposure was assigned as: 1) the estimated outdoor NO(2) levels at home, and 2) the average of estimated outdoor NO(2) levels at home and work, weighted according to the time spent in each environment. The subjects' socio-demographic and life-style information was obtained through a questionnaire. In the multiple linear analyses, the outdoor NO(2) levels assigned to each home were taken to be the dependent variable. Other variables included in the model were: age, country of origin, smoking during pregnancy, parity, season of the year, and social class. These same variables remained in the model when the dependent variable was changed to the NO(2) levels adjusted for the subjects' time-activity patterns. We found that younger women, those coming from Latin American countries, and those belonging to the lower social strata were exposed to higher NO(2) levels, both as measured outside their homes as well as when time-activity patterns were taken

  14. Monitoring of atmospheric ozone and nitrogen dioxide over the south of Portugal by ground-based and satellite observations.

    PubMed

    Bortoli, Daniele; Silva, Ana Maria; Costa, Maria João; Domingues, Ana Filipa; Giovanelli, Giorgio

    2009-07-20

    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed as a result of the collaboration between CGE-UE, ISAC-CNR and Italian National Agency for New Technologies, Energy and the Environment (ENEA). SPATRAM is a multi-purpose UV-Vis-scanning spectrometer (250 - 950 nm) and it is installed at the Observatory of the CGE, in Evora, since April 2004. A brief description of the instrument is given, highlighting the technological innovations with respect to the previous version of similar equipment. The need for such measurements automatically taken on a routine basis in south-western European regions, specifically in Portugal, has encouraged the development and installation of the equipment and constitutes a major driving force for the present work. The main features and some improvements introduced in the DOAS (Differential Optical Absorption Spectroscopy) algorithms are discussed. The results obtained applying DOAS methodology to the SPATRAM spectrometer measurements of diffused spectral sky radiation are presented in terms of diurnal and seasonal variations of nitrogen dioxide (NO(2)) and ozone (O(3)). NO(2) confirms the typical seasonal cycle reaching the maximum of (6.5 +/- 0.3) x 10(+15) molecules cm(-2) for the sunset values (PM), during the summer season, and the minimum of (1.55 +/- 0.07) x 10(+15) molecules cm(-2) for the sunrise values (AM) in winter. O(3) presents the maximum total column of (433 +/- 5) Dobson Unit (DU) in the spring season and the minimum of (284 +/- 3) DU during the fall period. The huge daily variations of the O(3) total column during the spring season are analyzed and discussed. The ground-based results obtained for NO(2) and O(3) column contents are compared with data from satellite-borne equipment (GOME - Global Ozone Monitoring Experiment; SCIAMACHY - Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY; TOMS - Total Ozone Monitoring Spectrometer) and it is shown that the two data

  15. Nitrogen dioxide and ultrafine particles dominate the biological effects of inhaled diesel exhaust treated by a catalyzed diesel particulate filter.

    PubMed

    Karthikeyan, Subramanian; Thomson, Errol M; Kumarathasan, Prem; Guénette, Josée; Rosenblatt, Debbie; Chan, Tak; Rideout, Greg; Vincent, Renaud

    2013-10-01

    We studied the impact of a catalyzed diesel particulate filter (DPF) on the toxicity of diesel exhaust. Rats inhaled exhaust from a Cummins ISM heavy-duty diesel engine, with and without DPF after-treatment, or HEPA-filtered air for 4h, on 1 day (single exposure) and 3 days (repeated exposures). Biological effects were assessed after 2h (single exposure) and 20h (single and repeated exposures) recovery in clean air. Concentrations of pollutants were (1) untreated exhaust (-DPF), nitric oxide (NO), 43 ppm; nitrogen dioxide (NO2), 4 ppm; carbon monoxide (CO), 6 ppm; hydrocarbons, 11 ppm; particles, 3.2×10(5)/cm(3), 60-70nm mode, 269 μg/m(3); (2) treated exhaust (+DPF), NO, 20 ppm; NO2, 16 ppm; CO, 1 ppm; hydrocarbons, 3 ppm; and particles, 4.4×10(5)/cm(3), 7-8nm mode, 2 μg/m(3). Single exposures to -DPF exhaust resulted in increased neutrophils, total protein and the cytokines, growth-related oncogene/keratinocyte chemoattractant, macrophage inflammatory protein-1α, and monocyte chemoattractant protein-1 in lung lavage fluid, as well as increased gene expression of interleukin-6, prostaglandin-endoperoxide synthase 2, metallothionein 2A, tumor necrosis factor-α, inducible nitric oxide synthase, glutathione S-transferase A1, heme oxygenase-1, superoxide dismutase 2, endothelin-1 (ET-1), and endothelin-converting enzyme-1 in the lung, and ET- 1 in the heart. Ratio of bigET-1 to ET-1 peptide increased in plasma in conjunction with a decrease in endothelial nitric oxide synthase gene expression in the lungs after exposure to diesel exhaust, suggesting endothelial dysfunction. Rather than reducing toxicity, +DPF exhaust resulted in heightened injury and inflammation, consistent with the 4-fold increase in NO2 concentration. The ratio of bigET-1 to ET-1 was similarly elevated after -DPF and +DPF exhaust exposures. Endothelial dysfunction, thus, appeared related to particle number deposited, rather than particle mass or NO2 concentration. The potential benefits of

  16. Broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Attwood, A. R.; Flores, J. M.; Zarzana, K. J.; Rudich, Y.; Brown, S. S.

    2016-01-01

    Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and it strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99930 ± 0.00003 (1- reflectivity = 700 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.43 km within the 1 m cell. We measure the cavity output over the 315-350 nm spectral region using a grating monochromator and charge-coupled device array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity-enhanced absorption spectroscopy and cavity ring-down spectroscopy agree within 2 % (slope for linear fit = 1.02 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity-enhanced absorption spectroscopy and calculated based on flow dilution are also well correlated, with r2 = 0.9998. During constant mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1 min detection limit for extinction measurements at 315-350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically based trace gas detection that may complement higher precision techniques based on non

  17. Monitoring of atmospheric ozone and nitrogen dioxide over the south of Portugal by ground-based and satellite observations.

    PubMed

    Bortoli, Daniele; Silva, Ana Maria; Costa, Maria João; Domingues, Ana Filipa; Giovanelli, Giorgio

    2009-07-20

    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed as a result of the collaboration between CGE-UE, ISAC-CNR and Italian National Agency for New Technologies, Energy and the Environment (ENEA). SPATRAM is a multi-purpose UV-Vis-scanning spectrometer (250 - 950 nm) and it is installed at the Observatory of the CGE, in Evora, since April 2004. A brief description of the instrument is given, highlighting the technological innovations with respect to the previous version of similar equipment. The need for such measurements automatically taken on a routine basis in south-western European regions, specifically in Portugal, has encouraged the development and installation of the equipment and constitutes a major driving force for the present work. The main features and some improvements introduced in the DOAS (Differential Optical Absorption Spectroscopy) algorithms are discussed. The results obtained applying DOAS methodology to the SPATRAM spectrometer measurements of diffused spectral sky radiation are presented in terms of diurnal and seasonal variations of nitrogen dioxide (NO(2)) and ozone (O(3)). NO(2) confirms the typical seasonal cycle reaching the maximum of (6.5 +/- 0.3) x 10(+15) molecules cm(-2) for the sunset values (PM), during the summer season, and the minimum of (1.55 +/- 0.07) x 10(+15) molecules cm(-2) for the sunrise values (AM) in winter. O(3) presents the maximum total column of (433 +/- 5) Dobson Unit (DU) in the spring season and the minimum of (284 +/- 3) DU during the fall period. The huge daily variations of the O(3) total column during the spring season are analyzed and discussed. The ground-based results obtained for NO(2) and O(3) column contents are compared with data from satellite-borne equipment (GOME - Global Ozone Monitoring Experiment; SCIAMACHY - Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY; TOMS - Total Ozone Monitoring Spectrometer) and it is shown that the two data

  18. Dual effect of nitrogen dioxide on barrier properties of guinea pig tracheobronchial epithelial monolayers cultured in an air interface

    SciTech Connect

    Robison, T.W.; Kim, K.J.

    1995-08-01

    Nitrogen dioxide (NO{sub 2}) is an oxidant gas that may injure the airway epithelial lining, leading to decrements in barrier and active ion transport properties. The present studies examined alterations of bioelectric properties and solute flux by guinea pig tracheobronchial epithelial (GPTE) monolayers exposed in vitro to NO{sub 2}. Confluent GPTE monolayers were exposed to NO{sub 2} levels between 0.5 and 5 ppm, while controls were exposed to air. Following exposure, monolayers were mounted in Ussing chambers for measurement of transepithelial resistance (R{sub te}) and short-circuit current (SCC). A 1-h exposure to 1 ppm NO{sub 2} significantly increased SCC to 131.3 {+-} 8.7% of air controls, while R{sub te} with a value of 109.3 {+-} 13.8% was unchanged. In contrast, a 1-h exposure to 2 or 5 ppm NO{sub 2} significantly decreased R{sub te} to 39.0 {+-} 1.6 or 33.5 {+-} 7.3% of air controls, respectively, while SCC values of 140.3 {+-} 10.4 or 153.3 {+-} 8.6%, respectively, were also significantly elevated. A 1-h exposure to 2 or 5 ppm NO{sub 2} significantly increased sucrose permeability across GPTE monolayers to 446.8 {+-} 117 or 313.3 {+-} 39.5% of air controls, respectively, while glycerol permeability was unchanged. In contrast, a 1-h exposure to 1 ppm NO{sub 2} produced no alterations of sucrose or glycerol flux. The SCC of control GPTE monolayers (1-h air exposure) consisted of 50% bumetanide-sensitive and 40% amiloride-sensitive current; exposure for 1 h to 2 ppm NO{sub 2} led to no changes in the corresponding SCC components. Active ion transport (i.e., SCC) across the airway epithelium was significantly increased after exposure to NO{sub 2} levels {le}1 ppm with no change of paracellular pathways for diffusion, suggesting that this reactive gas alters cell membrane function. The increased SCC may lead to impairment of fluid balance and mucociliary clearance. 34 refs., 4 figs.

  19. Raman spectroscopy of solutions and interfaces containing nitrogen dioxide, water, and 1,4 dioxane: Evidence for repulsion of surface water by NO{sub 2} gas

    SciTech Connect

    Murdachaew, Garold; Varner, Mychel E.; Veer, Wytze E. van der; Gerber, R. Benny; Phillips, Leon F.

    2014-05-14

    The interaction of water, 1,4 dioxane, and gaseous nitrogen dioxide, has been studied as a function of distance measured through the liquid-vapour interface by Raman spectroscopy with a narrow (<0.1 mm) laser beam directed parallel to the interface. The Raman spectra show that water is present at the surface of a dioxane-water mixture when gaseous NO{sub 2} is absent, but is virtually absent from the surface of a dioxane-water mixture when gaseous NO{sub 2} is present. This is consistent with recent theoretical calculations that show NO{sub 2} to be mildly hydrophobic.

  20. Nitrogen

    USGS Publications Warehouse

    Apodaca, L.E.

    2012-01-01

    Ammonia was produced by 12 companies at 27 plants in 15 states in the United States during 2011. Sixty-one percent of total U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2011, U.S. producers operated at about 84 percent of their rated capacity (excluding plants that were idle for the entire year). Four companies — CF Industries Holdings Inc.; Koch Nitrogen Co.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 77 percent of the total U.S. ammonia production capacity.

  1. Responses of soil respiration to elevated carbon dioxide and nitrogen addition in young subtropical forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Deng, Q.; Zhou, G.; Liu, J.; Liu, S.; Duan, H.; Zhang, D.

    2010-01-01

    Global climate change in the real world always exhibits simultaneous changes in multiple factors. Prediction of ecosystem responses to multi-factor global changes in a future world strongly relies on our understanding of their interactions. However, it is still unclear how nitrogen (N) deposition and elevated atmospheric carbon dioxide concentration [CO2] would interactively influence forest floor soil respiration in subtropical China. We assessed the main and interactive effects of elevated [CO2] and N addition on soil respiration by growing tree seedlings in ten large open-top chambers under CO2 (ambient CO2 and 700 μmol mol-1) and nitrogen (ambient and 100 kg N ha-1 yr-1) treatments. Soil respiration, soil temperature and soil moisture were measured for 30 months, as well as above-ground biomass, root biomass and soil organic matter (SOM). Results showed that soil respiration displayed strong seasonal patterns with higher values observed in the wet season (April-September) and lower values in the dry season (October-March) in all treatments. Significant exponential relationships between soil respiration rates and soil temperatures, as well as significant linear relationships between soil respiration rates and soil moistures (below 15%) were found. Both CO2 and N treatments significantly affected soil respiration, and there was significant interaction between elevated [CO2] and N addition (p<0.001, p=0.003, and p=0.006, respectively). We also observed that the stimulatory effect of individual elevated [CO2] (about 29% increased) was maintained throughout the experimental period. The positive effect of N addition was found only in 2006 (8.17% increased), and then had been weakened over time. Their combined effect on soil respiration (about 50% increased) was greater than the impact of either one alone. Mean value of annual soil respiration was 5.32 ± 0.08, 4.54 ± 0.10, 3.56 ± 0.03 and 3.53 ± 0.03 kg CO2 m-2 yr-1 in the chambers exposed to elevated [CO2] and

  2. Enantioselective small molecule synthesis by carbon dioxide fixation using a dual Brønsted acid/base organocatalyst.

    PubMed

    Vara, Brandon A; Struble, Thomas J; Wang, Weiwei; Dobish, Mark C; Johnston, Jeffrey N

    2015-06-17

    Carbon dioxide exhibits many of the qualities of an ideal reagent: it is nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents, however, it has found limited use in enantioselective synthesis. Moreover, unprecedented is a tool that merges one of the simplest biological approaches to catalysis-Brønsted acid/base activation-with this abundant reagent. We describe a metal-free small molecule catalyst that achieves the three component reaction between a homoallylic alcohol, carbon dioxide, and an electrophilic source of iodine. Cyclic carbonates are formed enantioselectively.

  3. Amino acid diagenesis, organic carbon and nitrogen mineralization in surface sediments from the inner Oslofjord, Norway

    SciTech Connect

    Haugen, J.E. ); Lichtentaler, R. )

    1991-06-01

    Total hydrolyzed amino acids (THAA), total organic carbon (TOC), and total nitrogen (TN) have been measured in an oxic and anoxic surface sediment from the inner Oslofjord. Downcore variations of these parameters are ascribed to both diagenesis and changes in organic matter supply, the latter being most important. These changes are most prominent in the anoxic sediment, which reflects the eutrophication history of the innermost part of the fjord. Downcore, THAA content decreased from 3.8 to 2.0 mg/g (salt-free dry weight) in the oxic sediment and from 22.3 to 3.8 mg/g in the anoxic sediment. Total amino acid nitrogen varied between 17 and 34% of total nitrogen in the oxic, and 25 and 54% in the anoxic, sediment. Organic carbon and organic nitrogen accumulation rates and depth integrated mineralization rates are about three times higher in the anoxic sediment than in the oxic sediment. Recycling of amino acids accounted for 4 to 12% of the total organic carbon and 13 to 40% of the total organic nitrogen regenerated in these sediments.

  4. A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides.

    PubMed

    Demkiw, Krystyna; Araki, Hirofumi; Elliott, Eric L; Franklin, Christopher L; Fukuzumi, Yoonjoo; Hicks, Frederick; Hosoi, Kazushi; Hukui, Tadashi; Ishimaru, Yoichiro; O'Brien, Erin; Omori, Yoshimasa; Mineno, Masahiro; Mizufune, Hideya; Sawada, Naotaka; Sawai, Yasuhiro; Zhu, Lei

    2016-04-15

    A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.

  5. Nitrogen mineralization rates of the acidic, xeric soils of the New Jersey Pinelands: field rates

    SciTech Connect

    Poovarodom, S.; Tate, R.L. III; Bloom, R.A.

    1988-04-01

    Using the buried-bag procedure, the authors quantified nitrogen mineralization rates in the xeric, acidic Lakehurst, and Atsion sands of the New Jersey Pine Barrens. Average annual nitrogen yields in the upper 15 cm for the Lakehurst and the Atsion sands were 38.4 and 53.0 kg N/ha, corresponding to 4.5 and 2.5% of the total nitrogen, respectively. Net nitrogen mineralization in both soils exhibited distinct seasonal patterns with maxima in summer and minimum rates in the winter. Nitrification accounted for only 5% of the total N mineralized in both soils. This is consistent with the finding of low populations of autotrophic nitrifiers in these soils.

  6. Adsorption of acids and bases from aqueous solutions onto silicon dioxide particles.

    PubMed

    Zengin, Huseyin; Erkan, Belgin

    2009-12-30

    The adsorption of acids and bases onto the surface of silicon dioxide (SiO(2)) particles was systematically studied as a function of several variables, including activation conditions, contact time, specific surface area, particle size, concentration and temperature. The physical properties of SiO(2) particles were investigated, where characterizations were carried out by FT-IR spectroscopy, and morphology was examined by scanning electron microscopy (SEM). The SEM of samples showed good dispersion and uniform SiO(2) particles with an average diameter of about 1-1.5 microm. The adsorption results revealed that SiO(2) surfaces possessed effective interactions with acids and bases, and greatest adsorption capacity was achieved with NaOH, where the best fit isotherm model was the Freundlich adsorption model. The adsorption properties of raw SiO(2) particles were further improved by ultrasonication. Langmuir monolayer adsorption capacity of NaOH adsorbate at 25 degrees C on sonicated SiO(2) (182.6 mg/g) was found to be greater than that of the unsonicated SiO(2) (154.3mg/g). The spontaneity of the adsorption process was established by decreases in DeltaG(ads)(0), which varied from -10.5 to -13.6 kJ mol(-1), in the temperature range 283-338K. PMID:19683387

  7. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

    PubMed

    Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  8. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

    PubMed Central

    Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  9. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

    PubMed

    Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  10. Nitrogen

    USGS Publications Warehouse

    Kramer, D.A.

    2004-01-01

    Ammonia is the principal source of fixed nitrogen. It was produced by 17 companies at 34 plants in the United States during 2003. Fifty-three percent of U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas, the dominant domestic feedstock.

  11. The assessment of acid-base disturbance in man by the use of carbon dioxide titration curves.

    PubMed

    Stoker, J B; Kappagoda, C T; Snow, H M; Linden, R J

    1975-02-01

    1. Carbon dioxide titration curves were determined in vivo in dog and man at various degrees of acute non-respiratory acidaemia and alkalaemia. 2. The slope of the CO2 titration curve (delta log Pco2/delta pH) was found to increase with the severity of the acute non-respiratory alkalaemia the slope (delta log Pco2/delta pH) tended towards unity. 3. A simple scheme based on the CO2 titration curves determined in vivo has been proposed for the assessment of acute acid-base disturbances in man. 4. Carbon dioxide titration curves were also determined in vivo in patients with chronic respiratory and non-respiratory acidaemia and it was found that these curves were not significantly different from those obtained in states of acute acid-base disturbances. It is therefore suggested that the scheme described in this paper is applicable to all acid-base disturbances.

  12. 78 FR 28173 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Sulfur Dioxide and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-14

    ... Dioxide and Nitrogen Dioxide Ambient Air Quality Standards AGENCY: Environmental Protection Agency (EPA... Indiana state implementation plan (SIP) for nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ) under...

  13. Use of inexpensive nitrogen sources and starch for L(+) lactic acid production in anaerobic submerged fermentation.

    PubMed

    Altaf, Md; Naveena, B J; Reddy, Gopal

    2007-02-01

    L(+) Lactic acid fermentation was studied by Lactobacillus amylophilus GV6 under the influence of inexpensive nitrogen sources (red lentil-RL, and Baker's yeast cells-YC) and starch by response surface methodology (RSM). Central composite rotatable design (CCRD) was employed to determine maximum lactic acid production at optimum values for process variables RL, YC and incubation period (IP) and a satisfactory fit model was realized. Lactic acid production was significantly affected by RL and IP interactions as well as by independent variables RL and YC. Maximum lactic acid production of 13.5 g/15.2g starch was obtained with RL 0.8%, YC 1% and IP of 48 h, with 92% lactic acid yield efficiency (g lactic acid produced/g substrate utilized) and 40% increase (from 50 g to 92 g/100 g starch utilized) in lactic acid production. This is the first report on response optimization in direct fermentation of starch to lactic acid using inexpensive nitrogen sources substituting peptone and yeast extract in anaerobic submerged fermentation by amylolytic lactic acid bacteria (LAB).

  14. Organic acids and selected nitrogen species for ABLE-3

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.

    1991-01-01

    The NASA Global Tropospheric Experiment (GTE) executed airborne science missions aboard the NASA Wallops Electra (NA429) in the North American high latitude (greater than 45 deg North) atmosphere during Jul. to Aug. 1988 and Jul. to Aug. 1990. These missions were part of GTE's Atmospheric Boundary Layer Experiment (ABLE). The 1988 mission , ABLE-3A, examined the ecosystems of Alaska as a source and/or sink for important tropospheric gases and particles, and gained new information on the chemical composition of the Arctic atmosphere during the summertime. During 1990 the second high latitude mission, ABLE-3B, focused on the Hudson Bay Lowland and Labrador regions of Canada. Both of these missions provided benchmark data sets on atmosphere biosphere exchange and atmospheric chemistry over largely uninhabited regions of North America. In support of the GTE/ABLE-3A and -3B field missions, the University of New Hampshire flew instrumentation aboard the Wallops Electra research aircraft to provide measurements of the trace gases nitric (HNO3), formic (HCOOH), and acetic (CH3COOH) acid. In addition, measurements were conducted to determine the major water soluble ionic composition of the atmospheric aerosol. For ABLE-3B, groundbased measurements of the acidic trace gases were also performed from the NASA micrometerological tower situated at Schefferville, Laborador. These measurements were aimed at assessing dry deposition of acidic gases to the taiga ecosystem in the Laborador region of Canada.

  15. Nitrogen cycling in s subarctic Alaskan watershed: the role of lichens and the potential effects of acid deposition

    SciTech Connect

    Gunther, A.J.

    1987-01-01

    It has been hypothesized that the loss of nitrogen-fixing lichens due to stress from air pollution could have adverse effects upon nitrogen availability, and thus primary productivity, in some ecosystems. There is general agreement, however, that the ecological role of these lichens has not been sufficiently well defined to determine whether they are keystone species. The objectives of this study were: (1) to examine the importance of nitrogen-fixing lichens to the nitrogen cycle in the drainage of Brooks Lake, Alaska, a nitrogen-limited nursery lake for the commercially important sockeye salmon (Oncorhychus nerka); and (2) to investigate the sensitivity of nitrogen fixation by lichens in this ecosystem to acid deposition. Biological nitrogen fixation was found to be the major source of new nitrogen to the Brooks Lake drainage. The rate of fixation is approximately 3 kg N/ha-yr, which compares to 0.3 kg N/ha-yr in precipitation and only 0.02 kg N/ha-yr in returning adult salmon. Cyanophillic lichens contribute about 0.21 kg N/ha-yr. The low levels of nitrogen in precipitation, combined with a lack of nitrogen-fixation activity in open lake waters, indicates that nitrogen in tributary streams is the major source of new nitrogen for Brooks Lake. The measurements of nitrogen inputs, along with estimates of other stocks and flows of nitrogen, were used to construct a steady-state box model of the nitrogen cycle in the drainage.

  16. Effects of breathing sulfur dioxide and an acidic sulfate aerosol during exercise on selected pulmonary function measurements

    SciTech Connect

    Jones, D.L.

    1985-01-01

    This study was undertaken to determine the effects of ambient air, acidic sulfate aerosol, sulfur dioxide, and the combination of sulfur dioxide and aerosol on selected pulmonary function measurements after 20 minutes of exercise at 75%-80% maximal heart rate in a hot (36-19/sup 0/C) and humid (70-90% RH) environment. Six male subjects between the ages 26 and 33 years with no pre-existing pulmonary or cardiovascular problems rode a stationary bicycle for 20 minutes during each exposure condition at a workload pre-set to assure that each subject would attain an average minute ventilation of 50-60 1/min (BTPS). Exposure to 2.5 ppm sulfur dioxide alone led to a significant lowering of FVC, FEV1, and FEF50. Exposure to sulfur dioxide plus aerosol led to a significant decrease of FVC. Baseline comparisons reflected a significant decline in FVC, FEV1, FEF25, FEF50, FEF75, and FEF25-75 between the pre-ambient and post-exposure. This decline suggests a residual effect of the air pollutant exposures. Significant differences were also observed between the pre-aerosol and pre-sulfur dioxide exposures for FVC, FEV1, FEF50, and FEF25-75.

  17. [Effects of low molecular organic acids on nitrogen accumulation, nodulation, and nitrogen fixation of soybean (Glycine max L.) under phosphorus deficiency stress].

    PubMed

    Wang, Shu-Qi; Han, Xiao-Zeng; Qiao, Yun-Fa; Yan, Jun; Li, Xiao-Hui

    2009-05-01

    A greenhouse sand culture experiment was conducted to study the effects of citric acid, oxalic acid, malic acid, and their mixture on the nitrogen accumulation, nodulation, and nitrogen fixation of soybean. After the application of test low molecular weight organic acids, the nitrogen accumulation in the aboveground part of soybean decreased by 17.6%-44.9% at seedling stage, 29.8%-88.4% at flowering stage, 9.18%-69.6% at podding stage, and 2.21%-41.7% at maturing stage). In the meanwhile, the nodule number, nitrogenase activity, and leghemoglobin content decreased by 11.4%-59.6%, 80.5%-91.7%, and 11.9%-59.9%, respectively, resulting in a significant decrease (9.71%-64.5%) of nitrogen fixation of soybean, compared with the control. The inhibitory effect of test low molecular weight organic acids increased with their increasing concentration. Oxalic acid had a higher inhibitory effect than citric acid and malic acid, and the mixture of the three organic acids had an enhanced inhibitory effect.

  18. Influence of experimental pulmonary emphysema on toxicological effects from inhaled nitrogen dioxide and diesel exhaust. Research report, January 1984-September 1987

    SciTech Connect

    Mauderly, J.L.; Bice, D.E.; Cheng, Y.S.; Gillett, N.A.; Henderson, R.F.

    1990-02-01

    The hypothesis tested in the project was that rats with preexisting experimentally-induced pulmonary emphysema were more susceptible than rats with normal lungs to the adverse effects of exposure to NO(sub 2) or diesel exhaust. Rats were exposed by inhalation seven hr/day, five day/wk, for 24 months to NO(sub 2) at 9.5 ppm, or to diesel exhaust at 3.5 mg soot/cu m, or to clean air. Pulmonary emphysema was induced in one-half of the rats by intratracheal instillation of elastase, six weeks before exposures. Nonneoplastic endpoints were evaluated after 12, 18, and 24 months of exposure. Nitrogen dioxide exposure of normal rats caused mild epithelial hyperplasia and inflammation in proximal alveoli. Significant interactions between the influences of emphysema and nitrogen dioxide were demonstrated to be additive for four parameters (out of 61 parameters). Diesel-exhaust exposure of normal rats caused progressive, focal inflammation, and epithelial proliferation. The final soot lung burden was only one-third of that in nonemphysematous lungs.

  19. Investigation of the sensitivity, selectivity, and reversibility of the chemically-sensitive field-effect transistor (CHEMFET) to detect nitrogen dioxide, dimethyl methylphosphonate, and boron trifluoride. Master's thesis

    SciTech Connect

    Hauschild, N.T.

    1993-09-01

    This study investigated the sensitivity, selectivity, and reversibility of a chemically-sensitive field-effect transistor (CHEMFET) gas microsensor. Various physical operating parameters were tested to determine which produced the most significant sensitivity, selectivity, and reversibility which were computed from response changes generated from electrical conductivity modulations when exposed to challenge gases. The variable operating parameters included: thinfilm material, film thickness, challenge gas specie, challenge gas concentration, and operating temperature. Copper phthalocyanine and lead phthalocyanine were used as thin films to detect the following challenge gases: nitrogen dioxide, dimethyl methylphosphonate, boron trifluoride, methanol, carbon monoxide, vinyl chloride, and trichloroethylene. Tests revealed that copper phthalocyanine was the most sensitive to dimethyl methylphosphonate and boron trifluoride, whereas lead phthalocyanine was the most sensitive to the remaining challenge gases. The CHEMFET was selective to the binary challenge gas combinations. The films were most selective for nitrogen dioxide. The CHEMFET was fully reversibly, and the time duration for full reversibility increased with increasing challenge gas concentrations and increasing time of exposure.

  20. Retrieval of stratospheric ozone and nitrogen dioxide profiles from Odin Optical Spectrograph and Infrared Imager System (OSIRIS) limb-scattered sunlight measurements

    NASA Astrophysics Data System (ADS)

    Haley, Craig Stuart

    2009-12-01

    Key to understanding and predicting the effects of global environmental problems such as ozone depletion and global warming is a detailed understanding of the atmospheric processes, both dynamical and chemical. Essential to this understanding are accurate global data sets of atmospheric constituents with adequate temporal and spatial (vertical and horizontal) resolutions. For this purpose the Canadian satellite instrument OSIRIS (Optical Spectrograph and Infrared Imager System) was launched on the Odin satellite in 2001. OSIRIS is primarily designed to measure minor stratospheric constituents, including ozone (O3) and nitrogen dioxide (NO2), employing the novel limb-scattered sunlight technique, which can provide both good vertical resolution and near global coverage. This dissertation presents a method to retrieve stratospheric O 3 and NO2 from the OSIRIS limb-scatter observations. The retrieval method incorporates an a posteriori optimal estimator combined with an intermediate spectral analysis, specifically differential optical absorption spectroscopy (DOAS). A detailed description of the retrieval method is presented along with the results of a thorough error analysis and a geophysical validation exercise. It is shown that OSIRIS limb-scatter observations successfully produce accurate stratospheric O3 and NO2 number density profiles throughout the stratosphere, clearly demonstrating the strength of the limb-scatter technique. The OSIRIS observations provide an extremely useful data set that is of particular importance for studies of the chemistry of the middle atmosphere. The long OSIRIS record of stratospheric ozone and nitrogen dioxide may also prove useful for investigating variability and trends.