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Sample records for ozone nitrogen dioxide

  1. 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).

  2. Pretreatment with nitrogen dioxide modifies plant response to ozone

    NASA Astrophysics Data System (ADS)

    Runeckles, V. C.; Palmer, K.

    Plant growth inhibition by ozone is significantly affected by previous exposure to nitrogen dioxide. Experiments on the early growth of four crop species showed that daily pretreatment with NO 2 (0.08-0.10 ppm for 3 h) immediately prior to exposure to O 3 (0.08-0.10 ppm for 6 h) increased the inhibition of radish and wheat growth, decreased the inhibition of bush bean growth, but had no effect on the growth of mint. The magnitudes of the interactive effects indicate that in regions where relatively high concentrations of O 3 are produced by photochemical processes, for example, downwind from urban centres, assessments of the impact of O 3 on vegetation based on knowledge of response to O 3 alone may be seriously flawed.

  3. Measurements of ozone, nitrogen dioxide, nitrous and nitric acids, and sulphur dioxide in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Vecera, V.; Mikuska, M.; Smolik, S.; Eleftheriadis, E.; Bryant, B.; Colbeck, C.; Lazaridis, L.

    2003-04-01

    Measurements of reactive nitrogen gases (NO_2, HONO, HNO_3), as well as ozone and sulfur dioxide were made over the Aegean Sea (the R/V Agaeon) within an air mass later reaching the Finokalia (Crete) sampling site. These measurements were carried out with unique gas trace instrumentation (wet effluent and "dry" diffusion denuder techniques, a chemiluminescent detection and chemiluminescent analyzers) during special conditions. There are significant differences in pollutant concentrations between results from Finokalia and from the R/V Agaeon. While at Finokalia concentrations of nitrogen dioxide, ozone and nitric and nitrous acids changed relatively slowly, the boat data showed a number of episodes with rapid changes in reactive nitrogen compounds and ozone concentrations. These episodes were correlated with the presence of boats up wind a short distance from the R/V Agaeon. Ozone concentrations at Finokalia and on the boat typically ranged between 40--80 ppb (v/v). Ozone concentrations reached up to 88 ppb (v/v) in the open sea. Nitrogen dioxide concentrations at Finokalia were in the range 0.5--3 ppb (v/v). Typical NO_2 concentrations observed aboard the boat were 4--6 ppb (v/v) with maxima of 20--30 ppb (v/v). During "spiked" episodes, up to 200 ppb (v/v) of nitrogen dioxide was observed while ozone concurrently was dramatically depleted down to 20 ppb (v/v). Concentrations of HONO and HNO_3 at Finokalia, in general, were low, typically in the order of 0.1--0.2 ppb (v/v) for HONO and 0.05--0.1 ppb (v/v) for HNO_3. On average, concentrations of both nitric and nitrous acids in the ambient air of the Aegean Sea were typically small, below 0.05 ppt (v/v). Within the "spiked" episodes up to 33 ppb (v/v) nitric acid and up to 2.5 ppb (v/v) nitrous acid were formed. The nitric acid "dry" denuder data were on average higher than the measurements by the wet efluent diffusion denuder. The concentration of SO_2 reached up to 9.2 ppb (v/v). The work was conducted within

  4. Monitoring of nitrogen dioxide, ozone and halogens radicals in Antarctica

    NASA Astrophysics Data System (ADS)

    Bortoli, Daniele; Ravegnani, Fabrizio; Costa, Maria J.; Genco, Silvia; Kulkarni, Pavan K.; Mendes, Rui; Domingues, Ana Filipa; Anton, Manuel; Giovanelli, Giorgio; Silva, Ana Maria

    2013-10-01

    Monitoring of atmospheric compounds at high latitudes is a key factor for a better understanding of the processes driving the chemical cycles of ozone and related chemical species. In this frame, the GASCOD (Gas Analizer Spectrometer Correlating Optical Differences) equipment is installed at the Mario Zucchelli Station (MZS - 74.69S, 164.12E) since December 1995, carrying out observations of nitrogen dioxide (NO2) and ozone (O3). The recent advances in sensor technologies and processor capabilities, suggested the setup of a new equipment, based on the same optical layout of the 'old' GASCOD , with enhanced performances and improved capabilities for the measurements of solar radiation in the UV-visible spectral range (300-700nm). The efforts accomplished, allowed for the increase of the investigated tracers. Actually, mainly due to the enlargement of the covered spectral range and to the adoption of a CCD sensor, in addition to the NO2 and O3 compounds, others species can be monitored with the new instrumental setup such as bromine, chlorine and iodine oxides (BrO, OClO and IO). The innovative equipment called GASCODNG (GASCOD New Generation) was installed at MZS during the 2012/2013 Italian Antarctic expedition, in the framework of the research projects SAMOA (Automatic Station Monitoring Antarctic Ozonosphere) and MATAGRO (Monitoring Atmospheric Tracers in Antarctica with Ground Based Observations) funded by the Italian and Portuguese Antarctic programs respectively. In this paper a brief description of the new equipment is provided, highlighting the main improvements with regard to the 'old' one. Furthermore the full dataset (1996 - 2012) of NO2 total columns, obtained with the GASCOD installed at MZS, is compared with the data obtained with satellite borne equipments (GOME, SCIAMACHY, OMI and GOME2) and the main statistical parameters are analyzed and discussed in detail.

  5. Transformation of nitrogen dioxide into ozone and prediction of ozone concentrations using multiple linear regression techniques.

    PubMed

    Ghazali, Nurul Adyani; Ramli, Nor Azam; Yahaya, Ahmad Shukri; Yusof, Noor Faizah Fitri M D; Sansuddin, Nurulilyana; Al Madhoun, Wesam Ahmed

    2010-06-01

    Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. This study examines transformation of nitrogen dioxide (NO(2)) into ozone (O(3)) at urban environment using time series plot. Data on the concentration of environmental pollutants and meteorological variables were employed to predict the concentration of O(3) in the atmosphere. Possibility of employing multiple linear regression models as a tool for prediction of O(3) concentration was tested. Results indicated that the presence of NO(2) and sunshine influence the concentration of O(3) in Malaysia. The influence of the previous hour ozone on the next hour concentrations was also demonstrated.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Direct measurements of ozone and nitrogen dioxide photolysis rates in the troposphere

    NASA Technical Reports Server (NTRS)

    Dickerson, R. R.; Stedman, D. H.; Delany, A. C.

    1982-01-01

    The photolysis frequencies of ozone and nitrogen dioxide were measured under a variety of conditions commonly found in the troposphere. Ozone photolysis frequencies show a strong dependence on solar zenith angle, overhead ozone column, and temperature, but only a weak dependence on altitude (when only downward radiation is detected). Nitrogen dioxide photolysis frequencies also show strong dependence on solar zenith angle, but show little dependence on temperature, pressure, or altitude. Both j values are strongly affected by cloud cover, but aerosol loading has much less effect. The disagreement of measured j(O3) and j(NO2) with many modeled values, especially disagreement over altitude dependence, shows that atmospheric UV radioactive processes are complicated and poorly understood, although experimental conditions may not always be applicable to conditions modeled.

  13. 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.

  14. 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.

  15. 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.

  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. 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.

  18. The use of nanocarbons as chemical filters for the selective detection of nitrogen dioxide and ozone.

    PubMed

    Spinelle, Laurent; Dubois, Marc; Brunet, Jérôme; Guérin, Katia; Parra, Vicente; Varenne, Christelle; Lauron, Bernard; Bouvet, Marcel; Hamwi, André; Pauly, Alain

    2010-09-01

    The gas filtering abilities of different nanocarbon materials such as nanocones/nanodiscs, and nanofibres, either as-prepared or modified by physical (annealing, grinding) or chemical (fluorination) treatment are reported. The aptitude to filter nitrogen dioxide and ozone, two of the most significant gaseous pollutants of the atmosphere, have been correlated to both the BET specific surface area studied by N2 adsorption at 77 K, and the presence of chemical functional groups at the surface. Valuable information regarding the mechanisms of gas-nanocarbon interaction has been obtained, in terms of chemisorption and physisorption. A prototype microsystem is proposed for the selective measurement of nitrogen dioxide and ozone concentration by means of organic semiconductor gas sensors.

  19. 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.

  20. 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.

  1. Formation of strong airway irritants in mixtures of isoprene/ozone and isoprene/ozone/nitrogen dioxide.

    PubMed Central

    Wilkins, C K; Clausen, P A; Wolkoff, P; Larsen, S T; Hammer, M; Larsen, K; Hansen, V; Nielsen, G D

    2001-01-01

    We evaluated the airway irritation of isoprene, isoprene/ozone, and isoprene/ozone/nitrogen dioxide mixtures using a mouse bioassay, from which we calculated sensory irritation, bronchial constriction, and pulmonary irritation. We observed significant sensory irritation (approximately 50% reduction of mean respiratory rate) by dynamically exposing the mice, over 30 min, to mixtures of isoprene and O3 or isoprene, O3, and NO2. The starting concentrations were approximately 4 ppm O3 and 500 ppm isoprene (+ approximately 4 ppm NO2. The reaction mixtures after approximately 30 sec contained < 0.2 ppm O3. Addition of the effects of the residual reactants and the identified stable irritant products (formaldehyde, formic acid, acetic acid, methacrolein, and methylvinyl ketone) could explain only partially the observed sensory irritation. This suggests that one or more strong airway irritants were formed. It is thus possible that oxidation reactions of common unsaturated compounds may be relevant for indoor air quality. PMID:11673123

  2. Total Column Observation of Nitrogen Dioxide and Ozone in the Four Corners Region

    NASA Astrophysics Data System (ADS)

    Butterfield, Z.; Dubey, M.; Lindenmaier, R.; Herman, J. R.; Disterhoft, P.; Minschwaner, K.

    2013-12-01

    Nitrogen Dioxide (NO2) is a pollutant created by the burning of fossil fuels, which is intricately related to levels of ozone (O3), a tropospheric pollutant and greenhouse gas. Observing and understanding the behavior of these two chemicals in the atmosphere is essential to monitoring and verifying power plant emissions. In the Four Corners region, the San Juan and Four Corners power plants produce a total of 0.3 kilotonnes of NOX (combined Nitric Oxide (NO) and NO2) per day from burning fossil fuels. We compare NO2 column measurements from a ground-based solar spectrometer (Pandora) and from the satellite-based Ozone Monitoring Instrument (OMI). We also compare O3 column measurements obtained from Pandora and a Brewer Ozone Spectrophotometer. Using O3 profiles obtained with ozonesondes and by separating long and short time scale changes in total column measurements we isolate tropospheric ozone columns and explore their relationship with the troposphere-dominated total column measurements of NO2.

  3. 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.

  4. Heterogeneous reactions of polycyclic aromatic hydrocarbons in presence of ozone and nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Kubatova, A.; Jeong, H.; Fisseha, R.; Smith, A.; Hadadi, S.; Dongari, N.; Cochran, R.; Beranek, J.

    2011-12-01

    Currently, the mutagenic character of diesel exhaust particulate matter (PM) is mainly attributed to nitro-polycyclic aromatic hydrocarbons (nitro-PAHs). However, several toxicological studies have ascribed a significant genotoxicity of PM to higher polarity species, suggesting the occurrence of dinitro-, hydroxy- and oxy-PAH derivatives. Unfortunately, only limited knowledge is available in the literature on the products of heterogeneous reactions of PAHs adsorbed on PM. Therefore in this work, we report a study on heterogeneous reactions of four semivolatile 3- and 4-ring PAHs with ozone and nitrogen dioxide. These PAHs (i.e., phenanthrene, anthracene, pyrene, and fluoranthene) were selected based on their significant partitioning into the particle phase in real-world PM. We have focused on the detailed identification of the reaction products using a series of derivatization techniques (i.e. N,O-bis (trimethylsilyl) trifluoroacetamide and pentafluorobenzyl)hydroxylamine hydrochloride), and commercially available and synthesized standards to ensure accurate identification. A number of oxidation products, mainly those of pyrene and anthracene, with multiple functionalities forming carboxaldehydes, carboxylic acids, and/or hydroxylated species were observed upon reaction with ozone. As reported previously, only single isomers of 1-nitropyrene and 9-nitroanthracene were found for the reaction with nitrogen dioxide. In contrast, the combination of a primary oxidant (ozone) and NO2 lead to the observation of a broader distribution of nitration products, apparently due to the in-situ formation of NO3, a more powerful oxidant. The identified reaction products will enable further evaluation of product accumulation kinetics and determine their significance in atmospheric processes.

  5. 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...

  6. 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...

  7. 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...

  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. Effect of nitrogen dioxide and ozone on the risk of dying in patients with severe asthma

    PubMed Central

    Sunyer, J; Basagana, X; Belmonte, J; Anto, J

    2002-01-01

    Background: A study was performed to assess the acute association between air pollution, pollen and spores, and mortality in a population based cohort of subjects with asthma recruited from emergency room admissions for an asthma exacerbation using a case crossover design. Methods: Patients in Barcelona aged over 14 years who died during the period 1985–95 who had visited the emergency department of one of the four largest hospitals in the city for asthma during 1985–9 were included in the study (a total of 467 men and 611 women). Deaths were identified by record linkage of the cohort individuals with the Catalonia mortality registry. Causes of death were based on the underlying cause on the death certificate. Air pollution, pollen and spore levels were measured at the city monitoring stations which provide an average for the entire city. Results: Nitrogen dioxide was associated with mortality for all causes of death (adjusted odds ratio (OR) for an increase of the interquartile range = 1.50, 95% confidence interval (CI) 1.09 to 2.64) in asthmatic patients with more than one emergency room admission for asthma. The association was particularly strong for respiratory causes (OR 1.63, 95% CI 0.93 to 2.86). Ozone also increased the risk of death in asthmatic patients (OR 1.90, 95% CI 1.09 to 3.30) during spring and summer. The association with particles, pollen, and spores was not significant, and no interactions between air pollutants and pollen and spores were found. Conclusion: Nitrogen dioxide and ozone may exacerbate severe asthma and even cause death among asthmatic subjects. PMID:12149528

  10. Evaluation of ozone, nitrogen dioxide, and carbon monoxide at nine sites in Saudi Arabia during 2007.

    PubMed

    Butenhoff, Christopher L; Khalil, M Aslam K; Porter, William C; Al-Sahafi, Mohammed Saleh; Almazroui, Mansour; Al-Khalaf, Abdulrahman

    2015-07-01

    This paper presents a one-year record of in situ air-quality data from nine sites throughout Saudi Arabia. The data set is composed of hourly measurements of ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO) at six of the largest cities in Saudi Arabia (Riyadh, Jeddah, Makkah, Yanbu, Dammam, Hafouf) and two remote locations in the mountainous southwestern region of Alsodah for the year 2007. The authors found that international O3 and CO standards were routinely exceeded throughout the year at many sites, and that exceedances increased during Ramadan (Sep. 12-Oct. 13), the Islamic month of fasting when much of normal daily activity is shifted to nighttime hours. In general NO2 and CO levels were higher in Saudi cities compared to U.S. cities of comparable population, while O3 levels were lower. There was a general trend for O3 and NO2 to be negatively correlated in Saudi cities in contrast to U.S. cities where the correlation is positive, suggesting that ozone chemistry in Saudi Arabia is limited by volatile organic compound emissions. This may be caused by low biogenic emissions from vegetation. Pollutant levels were lower at most Saudi sites during the four day Hajj period (Dec. 18-21) but higher in Makkah which receives millions of visitors during Hajj. The authors also found that ozone levels were elevated during the weekend (Thursday & Friday) relative to weekday levels despite lower NO2, a phenomenon known as the "weekend effect." As little air quality data is available from Saudi Arabia in the English-language literature, this data set fills a knowledge gap and improves understanding of air quality in an important but under-reported region of the world. Air quality measurements at nine sites in Saudi Arabia provide a detailed look at spatial and temporal patterns of ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO). NO2 and CO levels increased in most cities during the fasting month of Ramadan, whereas O3 levels decreased. This led to

  11. 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.

  12. 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

  13. 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.

  14. The impact of the choice of radiative transfer model and inversion method on the OSIRIS ozone and nitrogen dioxide retrievals

    NASA Astrophysics Data System (ADS)

    Haley, Craig; McLinden, Chris; Sioris, Christopher; Brohede, Samuel

    Key to the retrieval of stratospheric minor species information from limb-scatter measurements are the selections of a radiative transfer model (RTM) and inversion method (solver). Here we assess the impact of choice of RTM and solver on the retrievals of stratospheric ozone and nitrogen dioxide from the OSIRIS instrument using the ‘Ozone Triplet' and Differential Optical Absorption Spectroscopy (DOAS) techniques that are used in the operational Level 2 processing algorithms. The RTMs assessed are LIMBTRAN, VECTOR, SCIARAYS, and SASKTRAN. The solvers studied include the Maximum A Posteriori (MAP), Maximum Likelihood (ML), Iterative Least Squares (ILS), and Chahine methods.

  15. Effects of local meteorology and aerosols on ozone and nitrogen dioxide retrievals from OMI and pandora spectrometers in Maryland, USA during DISCOVER-AQ 2011.

    PubMed

    Reed, Andra J; Thompson, Anne M; Kollonige, Debra E; Martins, Douglas K; Tzortziou, Maria A; Herman, Jay R; Berkoff, Timothy A; Abuhassan, Nader K; Cede, Alexander

    An analysis is presented for both ground- and satellite-based retrievals of total column ozone and nitrogen dioxide levels from the Washington, D.C., and Baltimore, Maryland, metropolitan area during the NASA-sponsored July 2011 campaign of Deriving Information on Surface COnditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ). Satellite retrievals of total column ozone and nitrogen dioxide from the Ozone Monitoring Instrument (OMI) on the Aura satellite are used, while Pandora spectrometers provide total column ozone and nitrogen dioxide amounts from the ground. We found that OMI and Pandora agree well (residuals within ±25 % for nitrogen dioxide, and ±4.5 % for ozone) for a majority of coincident observations during July 2011. Comparisons with surface nitrogen dioxide from a Teledyne API 200 EU NOx Analyzer showed nitrogen dioxide diurnal variability that was consistent with measurements by Pandora. However, the wide OMI field of view, clouds, and aerosols affected retrievals on certain days, resulting in differences between Pandora and OMI of up to ±65 % for total column nitrogen dioxide, and ±23 % for total column ozone. As expected, significant cloud cover (cloud fraction >0.2) was the most important parameter affecting comparisons of ozone retrievals; however, small, passing cumulus clouds that do not coincide with a high (>0.2) cloud fraction, or low aerosol layers which cause significant backscatter near the ground affected the comparisons of total column nitrogen dioxide retrievals. Our results will impact post-processing satellite retrieval algorithms and quality control procedures.

  16. Performance Evaluation and Community Application of Low-Cost Sensors for Ozone and Nitrogen Dioxide

    PubMed Central

    Duvall, Rachelle M.; Long, Russell W.; Beaver, Melinda R.; Kronmiller, Keith G.; Wheeler, Michael L.; Szykman, James J.

    2016-01-01

    This study reports on the performance of electrochemical-based low-cost sensors and their use in a community application. CairClip sensors were collocated with federal reference and equivalent methods and operated in a network of sites by citizen scientists (community members) in Houston, Texas and Denver, Colorado, under the umbrella of the NASA-led DISCOVER-AQ Earth Venture Mission. Measurements were focused on ozone (O3) and nitrogen dioxide (NO2). The performance evaluation showed that the CairClip O3/NO2 sensor provided a consistent measurement response to that of reference monitors (r2 = 0.79 in Houston; r2 = 0.72 in Denver) whereas the CairClip NO2 sensor measurements showed no agreement to reference measurements. The CairClip O3/NO2 sensor data from the citizen science sites compared favorably to measurements at nearby reference monitoring sites. This study provides important information on data quality from low-cost sensor technologies and is one of few studies that reports sensor data collected directly by citizen scientists. PMID:27754370

  17. 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.

  18. Ozone, but not nitrogen dioxide, fragments elastin and increases its susceptibility to proteolysis.

    PubMed

    Winters, R S; Burnette-Vick, B A; Johnson, D A

    1994-10-01

    The effects of ozone (O3) and nitrogen dioxide (NO2) on the solubility and proteolytic susceptibility of elastin were examined to better understand how these oxidant air pollutants might damage the lung. In vitro O3 exposures at pH 7.4 resulted in the complete solubilization of elastin, but NO2 had no effect on solubility. The initial solubilization rate was 65 micrograms/mumol of O3, which increased to 150 micrograms/mumol in the midregion of a sigmoidal solubilization curve. Peptide fragments of the O3-solubilized elastin ranged in size from 5 to 20 kD. The conversion of insoluble elastin into soluble fragments by O3 was not due to the destruction of desmosine crosslinks. The effect of O3 on the proteolytic susceptibility of elastin was measured using insoluble elastin recovered from exposures that resulted in 5.3%, 12.8%, and 26.3% solubilization. Human neutrophil elastase (HNE) digested the remaining insoluble elastin samples 4.3, 6.0, and 9.8 times faster than unexposed elastin. In contrast, NO2-exposed elastin was no more susceptible to digestion by HNE. Ascorbate, EDTA, and uric acid reduced the proteolytic susceptibility of O3-exposed elastin, but mannitol afforded no protection. These findings indicate that the inhalation of O3 may contribute to lung disease by directly damaging elastin and by increasing its susceptibility to proteolysis, whereas NO2 probably damages lungs via alternative mechanisms.

  19. 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.

  20. Monitoring of atmospheric nitrogen dioxide using Ozone Monitoring Instrument remote sensing data

    NASA Astrophysics Data System (ADS)

    Xiao, Zhongyong; Jiang, Hong; Song, Xiaodong; Zhang, Xiuying

    2013-01-01

    Measurements from the Ozone Monitoring Instrument are used to investigate the temporal and spatial dynamics of global nitrogen dioxide (NO2). The results show that the global tropospheric column NO2 increased by 11.10% during 2005 to 2010 at a 1.76% annual growth rate. The largest tropospheric and total NO2 columns are mainly concentrated in the industrialized regions of North America, Europe, and east Asia. The large values of column NO are also observed and scattered in South America, Africa, and Indonesia due to biomass burning and savannah fires. Average tropospheric column NO increased by 32.62% at a 4.82% annual rate over eastern Asia. On the contrary, the trend decreased by 35.47% at a 7.04% annual rate over eastern America. The trend was not significant over Europe as a whole, where a decrease was observed over western and southern Europe and an increase was observed over eastern and northern Europe. Over the polluted urban areas, the ratios of tropospheric to total column NO2 are larger than 0.6 and the correlation coefficients are larger than 0.8. This can be mainly attributed to the anthropogenic NOx emissions over land, and it is noteworthy that the ratios are higher than 0.8 (correlation coefficients >0.95) over northern China.

  1. 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.

  2. Stratospheric Aerosol and Gas Experiment II measurements of the quasi-biennial oscillations in ozone and nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Zawodny, Joseph M.; Mccormick, M. P.

    1991-01-01

    The first measurements ever to show a quasi-biennial oscillation (QBO) in NO2 have been made by the Stratospheric Aerosol and Gas Experiment II) (SAGE II) and are presented in this work along with observations of the well-known QBO in stratospheric ozone. The SAGE II instrument was launched aboard the Earth Radiation Budget satellite near the end of 1984. Measurements of ozone and nitrogen dioxide through early 1990 are analyzed for the presence of a quasi-biennial oscillation. The measurements show the global extent of both the O3 and NO2 QBO in the 25- to 40-km region of the stratosphere. The SAGE II QBO results for ozone compare favorably to theory and previous measurements. The QBO in NO2 is found to be consistent with the vertical and horizontal transport of NOy. Both species exhibit a QBO at extratropical latitudes consistent with strong meridional transport into the winter hemisphere.

  3. Nitrogen dioxide, peroxynitrates, and the chemistry of tropospheric ozone production: New insights from in situ measurements

    NASA Astrophysics Data System (ADS)

    Thornton, Joel Andrew

    Nitrogen dioxide and its higher oxides (HNO4, HNO3) play a central role in tropospheric chemistry, regulating the production rates of ozone and controlling the chain length of the OH/HO2 catalytic cycle. Conversion of NO2 to long lived reservoirs such as peroxy(acyl)nitrates (RC(O)OONO2) allows for the transport of NOx (NO x ≡ NO + NO2) from source regions to the global atmosphere. This dissertation describes the design, development, and deployment of a time-gated laser-induced fluorescence (LIF) instrument capable of accurate (5%), precise (<5%), high time resolution (<1 Hz) measurements of ambient NO2 at parts per trillion mixing ratios from the ground and from aircraft based platforms. The deployment of a two-channel version of this NO2 LIF instrument fitted with heated inlets (TD-LIF) to measure ambient NO2 together with the sum total concentration of peroxynitrates is also described. Instrument performance is demonstrated with in-situ measurements from three field campaigns: (1) Blodgett Forest Reasearch Station (August--October 1998), (2) 1999 Southern Oxidants Study (June 15--July 15, 1999), (3) Tropospheric Ozone Production about the Spring Equinox (January--May, 2000). Results from comparisons of the LIF NO2 and total peroxynitrate measurements with independent techniques during these campaigns are presented, and suggest that the LIF and TD-LIF instruments provide substantial improvements to the accuracy, precision, and time resolution over existing nitrogen oxide measurement techniques. These measurements are used together with models to investigate the chemical and physical processes controlling O3 concentrations in the urban, rural, and remote troposphere. In urban and rural areas, the observations illustrate, for the first time, the transition of instantaneous O3 production rates in an urban environment from NOx-limited to NO x-saturated regimes, and the dependence of O3 production rates on both NOx abundances and HOx (HOx ≡ OH + HO2 + RO2) radical

  4. Impairment of humoral immune responses in mice exposed to nitrogen dioxide and ozone mixtures

    SciTech Connect

    Fujimaki, H.

    1989-04-01

    The relationship between immune defense mechanisms and environmental pollutants remains unknown because of uncertainty about the effects of combined or mixed pollutants. To investigate whether exposure to toxic gas mixtures change the effect of a single gas exposure on immune function, BALB/c mice were continuously exposed to 4.0 ppm nitrogen dioxide (NO/sub 2/), 0.8 ppm ozone (O/sub 3/), or the mixture of NO/sub 2/ plus O/sub 3/ for 3, 7, 14, and 56 days. Organ weights (lung, thymus, and spleen) and antibody responses to sheep red blood cells (SRBC), and to DNP-Ficoll were measured immediately after the exposure. Lung weights in mice exposed to O/sub 3/ or the mixture were increased significantly in all exposure periods. The weights of thymus and spleen in mice exposed for 3, 7, and 14 days to the mixture were decreased. O/sub 3/ exposure for 56 days showed significant decreases of the weights of both organs. Antibody response to SRBC in mice exposed for 3, 7, and 14 days to O/sub 3/ or the mixture was markedly suppressed, but exposure to the mixture for 56 days did not show the suppression of anti-SRBC antibody response. No differences in anti-DNP antibody response between exposed and control mice were observed, except those exposed to O/sub 3/ or the mixture for 14 days. These results suggest that mixed gas exposures variously modify the effects of a single gas exposure on antibody production in mice.

  5. 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).

  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. 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.

  8. 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.

  9. 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

  10. 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.

  11. The impact of the 2005 Gulf hurricanes on pollution emissions as inferred from Ozone Monitoring Instrument (OMI) nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Yoshida, Yasuko; Duncan, Bryan N.; Retscher, Christian; Pickering, Kenneth E.; Celarier, Edward A.; Joiner, Joanna; Boersma, K. Folkert; Veefkind, J. Pepijn

    2010-04-01

    The impact of Hurricanes Katrina and Rita in 2005 on pollution emissions in the Gulf of Mexico region was investigated using tropospheric column amounts of nitrogen dioxide (NO 2) from the Ozone Monitoring Instrument (OMI) on the NASA Aura satellite. Around New Orleans and coastal Mississippi, we estimate that Katrina caused a 35% reduction in NO x emissions on average in the three weeks after landfall. Hurricane Rita caused a significant reduction (20%) in NO x emissions associated with power generation and intensive oil refining activities near the Texas/Louisiana border. We also found a 43% decrease by these two storms over the eastern Gulf of Mexico Outer Continental Shelf mainly due to the evacuation of and damage to platforms, rigs, and ports associated with oil and natural gas production.

  12. Practical Use of Metal Oxide Semiconductor Gas Sensors for Measuring Nitrogen Dioxide and Ozone in Urban Environments

    PubMed Central

    Peterson, Philip J. D.; Aujla, Amrita; Brundle, Alex G.; Thompson, Martin R.; Vande Hey, Josh; Leigh, Roland J.

    2017-01-01

    The potential of inexpensive Metal Oxide Semiconductor (MOS) gas sensors to be used for urban air quality monitoring has been the topic of increasing interest in the last decade. This paper discusses some of the lessons of three years of experience working with such sensors on a novel instrument platform (Small Open General purpose Sensor (SOGS)) in the measurement of atmospheric nitrogen dioxide and ozone concentrations. Analytic methods for increasing long-term accuracy of measurements are discussed, which permit nitrogen dioxide measurements with 95% confidence intervals of 20.0 μg m−3 and ozone precision of 26.8 μg m−3, for measurements over a period one month away from calibration, averaged over 18 months of such calibrations. Beyond four months from calibration, sensor drift becomes significant, and accuracy is significantly reduced. Successful calibration schemes are discussed with the use of controlled artificial atmospheres complementing deployment on a reference weather station exposed to the elements. Manufacturing variation in the attributes of individual sensors are examined, an experiment possible due to the instrument being equipped with pairs of sensors of the same kind. Good repeatability (better than 0.7 correlation) between individual sensor elements is shown. The results from sensors that used fans to push air past an internal sensor element are compared with mounting the sensors on the outside of the enclosure, the latter design increasing effective integration time to more than a day. Finally, possible paths forward are suggested for improving the reliability of this promising sensor technology for measuring pollution in an urban environment. PMID:28753910

  13. Practical Use of Metal Oxide Semiconductor Gas Sensors for Measuring Nitrogen Dioxide and Ozone in Urban Environments.

    PubMed

    Peterson, Philip J D; Aujla, Amrita; Grant, Kirsty H; Brundle, Alex G; Thompson, Martin R; Vande Hey, Josh; Leigh, Roland J

    2017-07-19

    The potential of inexpensive Metal Oxide Semiconductor (MOS) gas sensors to be used for urban air quality monitoring has been the topic of increasing interest in the last decade. This paper discusses some of the lessons of three years of experience working with such sensors on a novel instrument platform (Small Open General purpose Sensor (SOGS)) in the measurement of atmospheric nitrogen dioxide and ozone concentrations. Analytic methods for increasing long-term accuracy of measurements are discussed, which permit nitrogen dioxide measurements with 95% confidence intervals of 20.0 μ g m - 3 and ozone precision of 26.8 μ g m - 3 , for measurements over a period one month away from calibration, averaged over 18 months of such calibrations. Beyond four months from calibration, sensor drift becomes significant, and accuracy is significantly reduced. Successful calibration schemes are discussed with the use of controlled artificial atmospheres complementing deployment on a reference weather station exposed to the elements. Manufacturing variation in the attributes of individual sensors are examined, an experiment possible due to the instrument being equipped with pairs of sensors of the same kind. Good repeatability (better than 0.7 correlation) between individual sensor elements is shown. The results from sensors that used fans to push air past an internal sensor element are compared with mounting the sensors on the outside of the enclosure, the latter design increasing effective integration time to more than a day. Finally, possible paths forward are suggested for improving the reliability of this promising sensor technology for measuring pollution in an urban environment.

  14. Vertical nitrogen dioxide and ozone concentrations measured from a tethered balloon in the Lower Fraser Valley

    NASA Astrophysics Data System (ADS)

    Pisano, J. T.; McKendry, I.; Steyn, D. G.; Hastie, D. R.

    A series of vertical profiles of temperature, relative humidity, NO 2 and O 3 were determined in the Lower Fraser Valley, British Columbia, as part of the PACIFIC '93 field study. Data from one day show very structured vertical distributions of all parameters in the morning, as expected from the limited vertical mixing under the nocturnal inversion. NO 2 concentrations of 20 ppbv were observed 300m above the surface, while the surface concentrations were ˜ 2 ppbv. Ozone and nitrogen oxide chemistry were observed at all altitudes throughout the PBL. Titration of O 3 by NO to produce NO 2 was observed in layers above the ground, under the influence of the NBL. An increase in odd oxygen throughout the PBL, during the morning and early afternoon, shows "smog chemistry" is occurring even though the ground-based O 3 measurements suggest this day was not particularly chemically active. However, once the NBL has dissipated, the ground-based measurements seem representative of the entire PBL.

  15. Atmospheric protein chemistry influenced by anthropogenic air pollutants: nitration and oligomerization upon exposure to ozone and nitrogen dioxide.

    PubMed

    Liu, Fobang; Lakey, Pascale S J; Berkemeier, Thomas; Tong, Haijie; Kunert, Anna Theresa; Meusel, Hannah; Cheng, Yafang; Su, Hang; Fröhlich-Nowoisky, Janine; Lai, Senchao; Weller, Michael G; Shiraiwa, Manabu; Pöschl, Ulrich; Kampf, Christopher J

    2017-08-24

    The allergenic potential of airborne proteins may be enhanced via post-translational modification induced by air pollutants like ozone (O3) and nitrogen dioxide (NO2). The molecular mechanisms and kinetics of the chemical modifications that enhance the allergenicity of proteins, however, are still not fully understood. Here, protein tyrosine nitration and oligomerization upon simultaneous exposure of O3 and NO2 were studied in coated-wall flow-tube and bulk solution experiments under varying atmospherically relevant conditions (5-200 ppb O3, 5-200 ppb NO2, 45-96% RH), using bovine serum albumin as a model protein. Generally, more tyrosine residues were found to react via the nitration pathway than via the oligomerization pathway. Depending on reaction conditions, oligomer mass fractions and nitration degrees were in the ranges of 2.5-25% and 0.5-7%, respectively. The experimental results were well reproduced by the kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB). The extent of nitration and oligomerization strongly depends on relative humidity (RH) due to moisture-induced phase transition of proteins, highlighting the importance of cloud processing conditions for accelerated protein chemistry. Dimeric and nitrated species were major products in the liquid phase, while protein oligomerization was observed to a greater extent for the solid and semi-solid phase states of proteins. Our results show that the rate of both processes was sensitive towards ambient ozone concentration, but rather insensitive towards different NO2 levels. An increase of tropospheric ozone concentrations in the Anthropocene may thus promote pro-allergic protein modifications and contribute to the observed increase of allergies over the past decades.

  16. The effects of rapid urbanization on the levels in tropospheric nitrogen dioxide and ozone over East China

    NASA Astrophysics Data System (ADS)

    Huang, Jianping; Zhou, Chenhong; Lee, Xuhui; Bao, Yunxuan; Zhao, Xiaoyan; Fung, Jimmy; Richter, Andreas; Liu, Xiong; Zheng, Yiqi

    2013-10-01

    Over the past few decades, China has experienced a rapid increase in urbanization. The urban built-up areas (population) in Beijing, Shanghai, and Guangzhou increased by 197% (87%), 148% (65%), and 273% (25%), respectively, from 1996 to 2011. We use satellite retrieval data to quantify the effects of rapid urbanization on the yearly and seasonal changes in tropospheric nitrogen dioxide (NO2) over East China. The results show that rapid urbanization has a profound effect on tropospheric columns of NO2. During 1996-2011, the tropospheric columns of NO2 over the surrounding areas of Guangzhou, Shanghai, and Beijing increased by 82%, 292%, and 307%, respectively. The tropospheric columns of NO2 reach their maximum in winter and minimum in spring. The anthropogenic emissions related to urbanization are a dominant factor in the long-term changes in the yearly and seasonal mean tropospheric columns of NO2, whereas meteorological conditions such as the prevailing winds and precipitation account for the unique spatial patterns. Around the time of the 2008 Beijing Olympic Games, the tropospheric columns of NO2 over Beijing urban area significantly reduced by 48% in July, 35% in August, and 49% in September, relative to the same monthly averages over 2005-2007. However, this trend was reversed after the Games, and the increased rate was even larger than before. Our results show that the tropospheric NO2 above the three regions increased at rates 1.3-8 times faster than the rates in a recent inventory estimate of NOx emissions for 2000-2010. We also discuss the influence of urbanization on tropospheric ozone and find that the Ozone Monitoring Instrument (OMI) retrieval tropospheric column shows that ozone levels are relatively insensitive to urbanization and changes in tropospheric NO2.

  17. 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.

  18. Growth, respiration and nitrogen content in needles of Scots pine exposed to elevated ozone and carbon dioxide in the field.

    PubMed

    Kellomäki, S; Wang, K Y

    1998-01-01

    Single Scots pine (Pinus sylvestris L.) trees, aged 30 years, were grown in open-top chambers and exposed to two atmospheric concentrations of ozone (O3; ambient and elevation) and carbon dioxide (CO2) as single variables or in combination for 3 years (1994-1996). Needle growth, respiration and nitrogen content were measured simultaneously over the period of needle expansion. Compared to ambient treatment (33 nmol mol(-1) O3 and 350 micromol mol(-1) CO2) doubled ambient O3 (69 nmol mol(-1)) significantly reduced the specific growth rates (SGRs) of the needles in the early stage of needle expansion and needle nitrogen concentration (N1) in the late stage, but increased apparent respiration rates (ARRs) in the late stage. Doubled ambient CO2 (about 650 micromol mol(-1)) significantly increased maximum SGR but reduced ARR and N1 in the late stage of needle expansion. The changes in ARR induced by the different treatments may be associated with treatment-induced changes in needle growth, metabolic activities and turnover of nitrogenous compounds. When ARR was partitioned into its two functional components, growth and maintenance respiration, the results showed that neither doubled ambient O3 nor doubled ambient CO2 influenced the growth respiration coefficients (Rg). However, doubled ambient O3 significantly increased the maintenance respiration coefficients (Rm) regardless of the needle development stage, while doubled ambient CO2 significantly reduced Rm only in the late stage of needle expansion. The increase in Rm under doubled ambient O3 conditions appeared to be related to an increase in metabolic activities, whereas the decrease in Rm under doubled ambient CO2 conditions may be attributed to the reduced N1 and turnover rate of nitrogenous compounds per unit. The combination of elevated O3 and CO2 had very similar effects on growth, respiration and N1 to doubled ambient O3 alone, but the interactive mechanism of the two gases is still not clear.

  19. 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.

  20. 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).

  1. 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

  2. EFFECTS OF CARBON DIOXIDE AND OZONE ON NITROGEN RETRANSLOCATION IN PONDEROSA PINE NEEDLES

    EPA Science Inventory

    Changes in leaf N concentration can be an important response to air pollutants in trees, with implications both for tree growth and N cycling through forest ecosystems. Ozone causes premature leaf senescence, which may be associated with a shift in N from the senescing leaves to...

  3. EFFECTS OF CARBON DIOXIDE AND OZONE ON NITROGEN RETRANSLOCATION IN PONDEROSA PINE NEEDLES

    EPA Science Inventory

    Changes in leaf N concentration can be an important response to air pollutants in trees, with implications both for tree growth and N cycling through forest ecosystems. Ozone causes premature leaf senescence, which may be associated with a shift in N from the senescing leaves to...

  4. Estimated Acute Effects of Ambient Ozone and Nitrogen Dioxide on Mortality in the Pearl River Delta of Southern China

    PubMed Central

    Tao, Yebin; Zhong, Liuju; Lu, Shou-En; Li, Yi; Dai, Lingzhen; Zhang, Yuanhang; Zhu, Tong

    2011-01-01

    Background and objectives: Epidemiologic studies have attributed adverse health effects to air pollution; however, controversy remains regarding the relationship between ambient oxidants [ozone (O3) and nitrogen dioxide (NO2)] and mortality, especially in Asia. We conducted a four-city time-series study to investigate acute effects of O3 and NO2 in the Pearl River Delta (PRD) of southern China, using data from 2006 through 2008. Methods: We used generalized linear models with Poisson regression incorporating natural spline functions to analyze acute mortality in association with O3 and NO2, with PM10 (particulate matter ≤ 10 μm in diameter) included as a major confounder. Effect estimates were determined for individual cities and for the four cities as a whole. We stratified the analysis according to high- and low- exposure periods for O3. Results: We found consistent positive associations between ambient oxidants and daily mortality across the PRD cities. Overall, 10-μg/m3 increases in average O3 and NO2 concentrations over the previous 2 days were associated with 0.81% [95% confidence interval (CI): 0.63%, 1.00%] and 1.95% (95% CI: 1.62%, 2.29%) increases in total mortality, respectively, with stronger estimated effects for cardiovascular and respiratory mortality. After adjusting for PM10, estimated effects of O3 on total and cardiovascular mortality were stronger for exposure during high-exposure months (September through November), whereas respiratory mortality was associated with O3 exposure during nonpeak exposure months only. Conclusions: Our findings suggest significant acute mortality effects of O3 and NO2 in the PRD and strengthen the rationale for further limiting the ambient pollution levels in the area. PMID:22157208

  5. Fifteen years of stratospheric nitrogen dioxide and ozone measurements in Antarctica

    NASA Astrophysics Data System (ADS)

    Bortoli, D.; Ravegnani, F.; Giovanelli, G.; Kulkarni, P. S.; Anton, M.; Costa, M. J.; Silva, A. M.

    2013-05-01

    The stratospheric NO2 and O3 total columns and vertical profiles retrieved from the measurements performed the last 15 years by the GASCOD spectrometer installed at the Mario Zucchelli Antarctic Station (MZS) - 74.69S, 164.12E, are presented here and briefly discussed. The full dataset of the spectral data obtained with GASCOD during the period 1996-2009, was re-analyzed with a modified version of the software tool previously utilized. The uncertainties range from 4% up to 8% for O3 and from 3% tup o 6% for NO2. The peculiar features of the seasonal variation of O3 (i.e. during the 'Ozone Hole' periods (mid-August to mid-October) and NO2 total columns (i.e. the normal decreasing during the austral fall and the irregular growing towards the spring months) are clearly identified. For the first time, the NO2 total columns values, obtained with the GASCOD installed at MZS, are compared with the data obtained with satellite borne equipments (SCIAMACHY, GOME and OMI).

  6. 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.

  7. An Overview of Striking Scientific Applications of Nitrogen Dioxide Retrievals from the Ozone Monitoring Instrument Between 2004 and 2014

    NASA Astrophysics Data System (ADS)

    Boersma, K. F.

    2014-12-01

    Nitrogen oxides are involved in many atmospheric processes relevant to air pollution, climate change, and environmental stress. Gaseous nitrogen oxides are toxic, regulated by regional authorities and the WHO, and their emissions and chemistry are important for the formation of ozone and aerosols. Nitrogen oxides are thought to act as a net climate cooler, mostly via enhancing the oxidative capacity of the global troposphere resulting in CH4 lifetime reductions, and via the formation of light-scattering particles. In this paper I will discuss how tropospheric NO2 column retrievals from the Ozone Monitoring Instrument on board EOS-Aura have pushed the envelope in various scientific applications over the last decade. A categorization of these applications shows that OMI NO2 data have been used for (1) high-resolution monitoring of NOx emissions, (2) monitoring trends in NO2 air pollution levels, (3) evaluating mid-day NOx chemistry, (4) evaluating secondary pollutant formation, (5) estimating surface NO2 concentrations, (6) improving forecasting skills of air quality and chemistry transport models, (7) estimating nitrogen deposition to ecosystems, and (8) outreach activities to the general public. I will show some intriguing examples of the above applications, and pay close attention to the steps necessary to arrive at these successful applications. These steps include advanced filtering of the data for e.g. wind direction or speed, spatial pattern recognition to isolate specific emission categories, and more generally improving the description of NOx emission categories and chemistry in models at spatial and temporal scales relevant to OMI and upcoming TROPOMI and geostationary sensors.

  8. Comparison of spatiotemporal prediction models of daily exposure of individuals to ambient nitrogen dioxide and ozone in Montreal, Canada.

    PubMed

    Buteau, Stephane; Hatzopoulou, Marianne; Crouse, Dan L; Smargiassi, Audrey; Burnett, Richard T; Logan, Travis; Cavellin, Laure Deville; Goldberg, Mark S

    2017-07-01

    In previous studies investigating the short-term health effects of ambient air pollution the exposure metric that is often used is the daily average across monitors, thus assuming that all individuals have the same daily exposure. Studies that incorporate space-time exposures of individuals are essential to further our understanding of the short-term health effects of ambient air pollution. As part of a longitudinal cohort study of the acute effects of air pollution that incorporated subject-specific information and medical histories of subjects throughout the follow-up, the purpose of this study was to develop and compare different prediction models using data from fixed-site monitors and other monitoring campaigns to estimate daily, spatially-resolved concentrations of ozone (O3) and nitrogen dioxide (NO2) of participants' residences in Montreal, 1991-2002. We used the following methods to predict spatially-resolved daily concentrations of O3 and NO2 for each geographic region in Montreal (defined by three-character postal code areas): (1) assigning concentrations from the nearest monitor; (2) spatial interpolation using inverse-distance weighting; (3) back-extrapolation from a land-use regression model from a dense monitoring survey, and; (4) a combination of a land-use and Bayesian maximum entropy model. We used a variety of indices of agreement to compare estimates of exposure assigned from the different methods, notably scatterplots of pairwise predictions, distribution of differences and computation of the absolute agreement intraclass correlation (ICC). For each pairwise prediction, we also produced maps of the ICCs by these regions indicating the spatial variability in the degree of agreement. We found some substantial differences in agreement across pairs of methods in daily mean predicted concentrations of O3 and NO2. On a given day and postal code area the difference in the concentration assigned could be as high as 131ppb for O3 and 108ppb for NO2. For

  9. Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas Experiment III (SAGE III) measurements using a new algorithm

    NASA Astrophysics Data System (ADS)

    Polyakov, A. V.; Timofeyev, Y. M.; Ionov, D. V.; Virolainen, Y. A.; Steele, H. M.; Newchurch, M. J.

    2005-03-01

    We describe a new inversion algorithm developed for the retrieval of atmospheric constituents from Stratospheric Aerosol and Gas Experiment III (SAGE III) solar occultation measurements. The methodology differs from the operational (NASA) algorithm in several important ways. Our algorithm takes account of the finite altitude and spectral resolution of the measurements by integrating over the viewing window spectrally and spatially. We solve the problem nonlinearly by using optimal estimation theory, and we use an aerosol parameterization scheme based on eigenvectors derived from existing empirical and modeled information about their microphysical properties. The first four of these eigenvectors are employed in the retrieval algorithm to describe the spectral variation of the aerosol extinction. We retrieve ozone and nitrogen dioxide number densities and aerosol extinction from transmission measurements at 41 channels from 0.29 to 1.55 μm. In this paper we describe the results of the gas retrievals. Numerical simulations test the accuracy of the scheme, and subsequent retrievals from SAGE III transmission data for the period between May and October 2002 produce profiles of O3 and NO2. Comparisons of the O3 and NO2 profiles with those obtained using the SAGE III operational algorithm and with those from independent measurements made by satellites, ozonesondes, and lidar indicate agreement in ozone measurements in the middle and upper stratosphere significantly closer than the natural variability and agreement in the lower stratosphere and upper troposphere approximately equal to the natural variability.

  10. Subalpine grassland carbon dioxide fluxes indicate substantial carbon losses under increased nitrogen deposition, but not at elevated ozone concentration

    NASA Astrophysics Data System (ADS)

    Volk, Matthias; Obrist, Daniel; Novak, Kris; Giger, Robin; Bassin, Seraina; Fuhrer, Jürg

    2010-05-01

    Ozone (O3) and nitrogen (N) deposition affect plant carbon (C) dynamics and may thus change ecosystem C-sink/-source properties. We studied effects of increased background O3 concentrations (up to ambient x 2) and increased N deposition (up to +50 kg ha-1 a-1) on mature, subalpine grassland during the third treatment year. During ten days and 13 nights, covering the vegetation period of 2006, we measured ecosystem-level CO2 exchange using a steady state cuvette. Light dependency of gross primary production (GPP) and temperature dependency of ecosystem respiration rates (Reco) were established. Soil temperature, soil water content, and solar radiation were monitored. Using Reco and GPP values, we calculated seasonal net ecosystem production (NEP), based on hourly averages of global radiation and soil temperature. Differences in NEP were compared to differences in soil organic C after five years of treatment. Under high O3 and with unchanged aboveground biomass, both mean Reco and GPP decreased throughout the season. Thus, NEP indicated an unaltered growing season CO2-C balance. Under high N treatment, with a +31% increase in aboveground productivity, mean Reco, but not GPP increased. Consequently, seasonal NEP yielded a 53.9 g C m-2 (± 22.05) C loss compared to control. Independent of treatment, we observed a negative NEP of 146.4 g C m-2 (±15.3). This C loss was likely due to a transient management effect, equivalent to a shift from pasture to hay meadow and a drought effect, specific to the 2006 summer climate. We argue that this resulted from strongly intensified soil microbial respiration, following mitigation of nutrient limitation. There was no interaction between O3 and N treatments. Thus, during the 2006 growing season, the subalpine grassland lost >2% of total topsoil organic C as respired CO2, with increased N deposition responsible for one-third of that loss.

  11. 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.

  12. The exceedance patterns of air quality criteria: a case study of ozone and nitrogen dioxide in Seoul, Korea between 1990 and 2000.

    PubMed

    Kim, Ki-Hyun; Choi, Ye-Jin; Kim, Min-Young

    2005-07-01

    In this study, the environmental behavior of two major airborne pollutants, ozone and nitrogen dioxide, was investigated with respect to their exceedance patterns of air quality criteria. For this purpose, we used data sets collected from a total of 31 air quality monitoring stations dispersed across the Seoul metropolitan city between 1990 and 2000. In the case of NO(2), the frequency of hourly exceedance data sets exhibited little changes in the early 90s. However, it increased dramatically after 1995, probably in compliance with a rapid increase in the total number of automobiles. Likewise, the daily exceedance of O(3) in the early 90s was not significant, approaching 100 cases (except in 1994). However, its total quantity began to surpass 300 cases since around 1996. Comparison of those exceedance data was also made among spatially divided data groups. In the case of NO(2), the occurrence of exceedance data was dominated by the western part of the city in both magnitude and frequency. On the other hand, that for O(3) was characterized by notably strong occurrences in the eastern counterpart. The overall results of our analysis of the NO(2) and O(3) exceedance data sets indicate an inextricable linkage between the two pollutants in association with geographical and meteorological factors.

  13. Exposure assessment of air pollutants: a review on spatial heterogeneity and indoor/outdoor/personal exposure to suspended particulate matter, nitrogen dioxide and ozone

    NASA Astrophysics Data System (ADS)

    Monn, Christian

    This review describes databases of small-scale spatial variations and indoor, outdoor and personal measurements of air pollutants with the main focus on suspended particulate matter, and to a lesser extent, nitrogen dioxide and photochemical pollutants. The basic definitions and concepts of an exposure measurement are introduced as well as some study design considerations and implications of imprecise exposure measurements. Suspended particulate matter is complex with respect to particle size distributions, the chemical composition and its sources. With respect to small-scale spatial variations in urban areas, largest variations occur in the ultrafine (<0.1 μm) and the coarse mode (PM 10-2.5, resuspended dust). Secondary aerosols which contribute to the accumulation mode (0.1-2 μm) show quite homogenous spatial distribution. In general, small-scale spatial variations of PM 2.5 were described to be smaller than the spatial variations of PM 10. Recent studies in outdoor air show that ultrafine particle number counts have large spatial variations and that they are not well correlated to mass data. Sources of indoor particles are from outdoors and some specific indoor sources such as smoking and cooking for fine particles or moving of people (resuspension of dust) for coarse particles. The relationships between indoor, outdoor and personal levels are complex. The finer the particle size, the better becomes the correlation between indoor, outdoor and personal levels. Furthermore, correlations between these parameters are better in longitudinal analyses than in cross-sectional analyses. For NO 2 and O 3, the air chemistry is important. Both have considerable small-scale spatial variations within urban areas. In the absence of indoor sources such as gas appliances, NO 2 indoor/outdoor relationships are strong. For ozone, indoor levels are quite small. The study hypothesis largely determines the choice of a specific concept in exposure assessment, i.e. whether personal

  14. Analysis of vertical ozone and nitrogen oxides profiles in a Prunus cerasifera canopy

    NASA Astrophysics Data System (ADS)

    Lorenzini, Giacomo; Nali, Cristina

    1995-03-01

    An automatic system was installed for continuous analyses of ozone, sulphur dioxide, nitrogen monoxide and nitrogen dioxide in an experimental orchard with a canopy of Prunus cerasifera plants in summer 1993. Air samples from three elevations (0.8 m, 1.6 m and 3 m above ground) were sequentially analyzed. Ozone concentrations above the canopy were usually higher than within the canopy; their relationships with stomatal resistance have been investigated. Sulphur dioxide levels were negligible. Nitrogen oxides showed a complex profile, with no particular trend, likely due to a reciprocal exchange between the atmosphere and the ground surface.

  15. SSTs, nitrogen fertiliser and stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Whitten, R. C.; Poppoff, I. G.; Capone, L. A.

    1978-01-01

    A recently revised model of the stratosphere is used to show that a substantial enhancement in the ozone layer could accompany worldwide SST fleet operations and that water vapor may be an important factor in SST assessments. Revised rate coefficients for various ozone-destroying reactions are employed in calculations which indicate a slight increase in the total content of stratospheric ozone for modest-sized fleets of SSTs flying below about 25 km. It is found that water-vapor chemical reactions can negate in large part the NOx-induced ozone gains computed below 25 km and that increased use of nitrogen fertilizer might also enhance the ozone layer.

  16. Sensitivity of ginseng to ozone and sulfur dioxide

    SciTech Connect

    Proctor, J.T.A.; Ormrod, D.P.

    1981-10-01

    American ginseng (Panax quinquefolius L.), was injured by exposure to 20 pphm ozone and/or 50 pphm (v/v) sulfur dioxide for 6 hr daily for 4 days. Ozone induced upper surface leaflet stippling along the veins and interveinally, and sulfur dioxide induced mild chlorosis to irregular necrotic areas. Ginseng was less sensitive to ozone and as sensitive to sulfur dioxide as 'Cherry Belle' radish (Raphanus sativus L.) and 'Bel W-3' tobacco (Nicotiana tabacum L.).

  17. Nitrogen Dioxide's Impact on Indoor Air Quality

    EPA Pesticide Factsheets

    The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant and corrosive. The primary sources indoors are combustion processes.

  18. 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

  19. Increase in tropospheric nitrogen dioxide over China observed from space.

    PubMed

    Richter, Andreas; Burrows, John P; Nüss, Hendrik; Granier, Claire; Niemeier, Ulrike

    2005-09-01

    Emissions from fossil fuel combustion and biomass burning reduce local air quality and affect global tropospheric chemistry. Nitrogen oxides are emitted by all combustion processes and play a key part in the photochemically induced catalytic production of ozone, which results in summer smog and has increased levels of tropospheric ozone globally. Release of nitrogen oxide also results in nitric acid deposition, and--at least locally--increases radiative forcing effects due to the absorption of downward propagating visible light. Nitrogen oxide concentrations in many industrialized countries are expected to decrease, but rapid economic development has the potential to increase significantly the emissions of nitrogen oxides in parts of Asia. Here we present the tropospheric column amounts of nitrogen dioxide retrieved from two satellite instruments GOME and SCIAMACHY over the years 1996-2004. We find substantial reductions in nitrogen dioxide concentrations over some areas of Europe and the USA, but a highly significant increase of about 50 per cent-with an accelerating trend in annual growth rate-over the industrial areas of China, more than recent bottom-up inventories suggest.

  20. Reaction between nitric oxide and ozone in solid nitrogen

    NASA Technical Reports Server (NTRS)

    Lucas, D.; Pimentel, G. C.

    1979-01-01

    Nitrogen dioxide, NO2, is produced when nitric oxide, NO, and ozone, O3, are suspended in a nitrogen matrix at 11-20 K. The NO2 is formed with first-order kinetics, a 12 K rate constant of (1.4 + or - 0.2) x 0.00001/sec, and an apparent activation energy of 106 + or - 10 cal/mol. Isotopic labeling, variation of concentrations, and cold shield experiments show that the growth of NO2 is due to reaction between ozone molecules and NO monomers, and that the reaction is neither infrared-induced nor does it seem to be a heavy atom tunneling process. Reaction is attributed to nearest-neighbor NO.O3 pairs probably held in a specific orientational relationship that affects the kinetic behavior. When the temperature is raised, more such reactive pairs are generated, presumably by local diffusion. Possible mechanisms are discussed.

  1. Nitrogen fertiliser and stratospheric ozone - Latitudinal effects

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Capone, L. A.; Riegel, C. A.; Turco, R. P.

    1980-01-01

    Substantial increases in atmospheric N2O resulting from the increased use of nitrogen fertilizers might cause large (to 10%) decreases in the stratospheric ozone content. Such ozone decreases would be caused by catalytic reaction cycles involving odd-nitrogen that is formed by N2O decomposition in the upper stratosphere. Turco et al. (1978), using a background chlorine level of 2 ppbv, have shown that if the measured values of specified reactions are used a 50% increase in N2O would lead to a 2.7% increase in the stratospheric column density, although the ozone content above 30 km would be reduced by more than 5%; they also estimated (unpublished data) that the change in the ozone column density caused by doubling the N2O abundance would be very close to zero (within about 0.1%). The present paper extends these calculations of N2O/ozone effects to two dimensions, thereby identifying the latitude dependence expected for such ozone perturbations. The effects of changes in stratospheric chlorine levels on predicted ozone changes are also discussed.

  2. Antipollution system to remove nitrogen dioxide gas

    NASA Technical Reports Server (NTRS)

    Metzler, A. J.; Slough, J. W.

    1971-01-01

    Gas phase reaction system using anhydrous ammonia removes nitrogen dioxide. System consists of ammonia injection and mixing section, reaction section /reactor/, and scrubber section. All sections are contained in system ducting.

  3. Monitoring of Occupational Exposure of Mild Steel Welders to Ozone and Nitrogen Oxides

    PubMed Central

    Esmaeilzadeh, Morteza; Mehrabi, Yadollah; Salehpour, Sousan

    2011-01-01

    Background Metal Inert Gas (MIG) welding and Tungsten Inert Gas (TIG) welding are widely used for mild steel segments in basic metal industries. Pulmonary problems such as asthma, pulmonary inflammation, hyper-responsiveness of airways and higher susceptibility to infections are reported as the result of occupational exposure of welders to ozone and nitrogen oxides. Potent oxidizing agents like ozone and nitrogen oxides are also reported to be a precursor for respiratory problems and cause lipid peroxidation of membranes. Materials and Methods A total of 43 nonsmoking MIG and TIG welders and 41 nonsmoking workers without appreciable exposure to any chemicals as the control population were chosen to participate in this study. Occupational exposure to ozone was monitored according to the validated methods. Malondialdehyde (MDA) of blood serum as a biomarker for lipid peroxidation was analyzed using Reverse Phase High Performance Liquid Chromatography. Data obtained from this study were analyzed using t-test, Pearson's correlation coefficient and multiple regression analysis. Results A total of 88.4% and 74.4% of welders had exposure to ozone and nitrogen dioxide higher than the permissible limit of occupational exposure, respectively. Generally, exposure of MIG welders to ozone was significantly higher than TIG welders (P = 0.006). However, exposure to nitrogen dioxide gas was comparable in both groups. Serum MDA of welders was significantly higher than that of the control group (P = 0.001). A significant correlation was detected between ozone exposure and level of serum malondialdehyde. Such correlation was not observed for nitrogen dioxide exposure. Conclusion Considering the high exposure of welders to ozone and nitrogen dioxide, and higher level of serum malondialdehyde in them compared to controls, risk management is recommended for this group of workers. PMID:25191389

  4. Monitoring of occupational exposure of mild steel welders to ozone and nitrogen oxides.

    PubMed

    Azari, Mansour R; Esmaeilzadeh, Morteza; Mehrabi, Yadollah; Salehpour, Sousan

    2011-01-01

    Metal Inert Gas (MIG) welding and Tungsten Inert Gas (TIG) welding are widely used for mild steel segments in basic metal industries. Pulmonary problems such as asthma, pulmonary inflammation, hyper-responsiveness of airways and higher susceptibility to infections are reported as the result of occupational exposure of welders to ozone and nitrogen oxides. Potent oxidizing agents like ozone and nitrogen oxides are also reported to be a precursor for respiratory problems and cause lipid peroxidation of membranes. A total of 43 nonsmoking MIG and TIG welders and 41 nonsmoking workers without appreciable exposure to any chemicals as the control population were chosen to participate in this study. Occupational exposure to ozone was monitored according to the validated methods. Malondialdehyde (MDA) of blood serum as a biomarker for lipid peroxidation was analyzed using Reverse Phase High Performance Liquid Chromatography. Data obtained from this study were analyzed using t-test, Pearson's correlation coefficient and multiple regression analysis. A total of 88.4% and 74.4% of welders had exposure to ozone and nitrogen dioxide higher than the permissible limit of occupational exposure, respectively. Generally, exposure of MIG welders to ozone was significantly higher than TIG welders (P = 0.006). However, exposure to nitrogen dioxide gas was comparable in both groups. Serum MDA of welders was significantly higher than that of the control group (P = 0.001). A significant correlation was detected between ozone exposure and level of serum malondialdehyde. Such correlation was not observed for nitrogen dioxide exposure. Considering the high exposure of welders to ozone and nitrogen dioxide, and higher level of serum malondialdehyde in them compared to controls, risk management is recommended for this group of workers.

  5. Nitrogen dioxide exposures inside ice skating rinks.

    PubMed Central

    Brauer, M; Spengler, J D

    1994-01-01

    OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

  6. Carbon and nitrogen co-dependence of soil microbial responses to elevated carbon dioxide and ozone in a wheat-soybean agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Climate change factors such as elevated atmospheric CO2 and ozone can exert significant impacts on soil microbes and microbially-mediated ecosystem processes. However, the underlying mechanisms through which soil microbes respond to these environmental changes remain poorly understood. The current ...

  7. 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 nitrogen...

  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 nitrogen...

  9. 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 nitrogen...

  10. 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 nitrogen...

  11. 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 nitrogen...

  12. Photoassisted Deposition of Silicon Dioxide from Silane and Nitrogen Dioxide

    DTIC Science & Technology

    1988-09-30

    Photoassisted Deposition of Silicon Dioxide N from Silane and Nitrogfen Diotde, J. MARKS, R. C. BO\\VMAN, Jr., and R.. E. ROBIERTSON Chemisty and...WCO OL-AB I UINCLASSIFIED uv ~E~ CAS(TXI WF MTHISPA REPORT DOCUMENTATION PAGE ItRPg EUM "IICTO 1b. RE STRICTIVE MARKINGS Unclassified...IDeposition of Silicon Dioxide from e and Nitrogen Dio2x 12. PERSONAL AUTHOR(S) 0Marks, Jeffrey Bowa Robert C., Jr.: anWRobertson. Rubv E. 13.TYPE OF

  13. 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...

  14. 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...

  15. EFFECTS OF OZONE, CHLORINE DIOXIDE, CHLORINE, AND MONOCHLORAMINE ON CRYTOSPORIDIUM PARVUM OOCYST VIABILITY

    EPA Science Inventory

    Purified Cryptosporiodium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were compareatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlor...

  16. Characteristics of total column ozone and nitrogen dioxide amount over Korea during the 2015 MAPS campaign: Pandora spectrometer, satellite and in-situ measurement

    NASA Astrophysics Data System (ADS)

    Go, S.; Chong, H. S.; Kim, W.; Kim, J.; Lee, H.; Kim, J. H.; KIM, J.; Herman, J. R.; Abuhassan, N.; Park, J. H.

    2015-12-01

    To improve the performances of satellite retrieval of surface pollution and air quality models, NIER (National Institute of Environmental Research) and NASA are planning the KORUS-AQ campaign over the Korean Peninsula in May-June, 2016. As a pre-campaign of the KORUS-AQ, MAPS (Megacity Air Pollution Studies)-Seoul was conducted from May to July, 2015. During this campaign, six Pandora instruments continuously provided total column density of O3 and NO2 over Korea. These measurements will be continued until the end of 2016 covering the KORUS-AQ campaign period and beyond for the initial validation of TROPOMI measurements. To assess the variation of O3 and NO2, data were collected from Pandora, Dobson spectrophotometer, Brewer spectrophotometer, other ground-based in situ measurements and Ozone Monitoring Instrument (OMI). Ozone column density from Pandora exhibited significantly high correlation (R2 > 0.8) with the ground-based Dobson and Brewer spectrophotometers. Due to the detector anomaly and wide spatial pixel coverage, O3 values from OMI showed lower correlation (R2 > 0.6) with the Pandora. Even though six Pandoras were scattered across the country, O3 data showed similar distribution, in accordance with the low spatial variability of ozone. On the contrary, NO2 distribution pattern showed large difference at each site, which showed peak at around 10 a.m., with larger diurnal variability in urban area than that in rural area by more than 5 times. As most of Pandora sites do not have on-site in situ NO2 measurements, other in situ data from the nearest Air Korea stations were used for the comparison. The comparison result showed significant correlation, although, the correlation coefficient was relatively lower than that of O3. Pandora measurements agreed well with the ground based instruments and OMI satellite data with averaged residuals less than 2% in O3. In case of NO2 Pandora measurements showed similar trend with in situ measurements.

  17. Austrian pine injury traced to ozone and sulfur dioxide pollution

    SciTech Connect

    Brennan, E.; Leone, I.; Harkov, R.; Rhoads, A.

    1981-04-01

    A foliar disorder of Austrian pine observed in New Jersey since 1967 was found to result from a mixture of ozone and sulfur dioxide. In fumigation chamber studies, a mixture of 0.2 ppm ozone and 0.1 ppm sulfur dioxide for 6 hr reproduced symptoms observed in the field. Grafted material originating from trees that exhibitied either a sensitive or resistant response in the field gave the same differential response in the experimental fumigation. Needles of resistant trees had higher stomatal resistance and higher soluble sugar content than needles of susceptible trees.

  18. The Impact of Increasing Carbon Dioxide on Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.; Douglass, Anne R.; Considine, David B.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    We have used the GSFC coupled two-dimensional (2D) model to study the impact of increasing carbon dioxide from 1980 to 2050 on the recovery of ozone to its pre-1980 amounts. We find that the changes in temperature and circulation arising from increasing CO2 affect ozone recovery in a manner which varies greatly with latitude, altitude, and time of year. Middle and upper stratospheric ozone recovers faster at all latitudes due to a slowing of the ozone catalytic loss cycles. In the lower stratosphere, the recovery of tropical ozone is delayed due to a decrease in production and a speed up in the overturning circulation. The recovery of high northern latitude lower stratospheric ozone is delayed in spring and summer due to an increase in springtime heterogeneous chemical loss, and is speeded up in fall and winter due to increased downwelling. The net effect on the higher northern latitude column ozone is to slow down the recovery from late March to late July, while making it faster at other times. In the high southern latitudes, the impact of CO2 cooling is negligible. Annual mean column ozone is predicted to recover faster at all latitudes, and globally averaged ozone is predicted to recover approximately ten years faster as a result of increasing CO2.

  19. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) ...

  20. 40 CFR 52.1876 - 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...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) ...

  1. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) ...

  2. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) ...

  3. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) ...

  4. 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.

  5. Hydrazine/nitrogen dioxide fiber optic sensor

    NASA Astrophysics Data System (ADS)

    Andrawis, Alfred A.; Santiago, Josephine; Young, Rebecca C.; Baum, J. Clayton

    2004-06-01

    This paper outlines the development of a dual hydrazine/nitrogen dioxide (HZ/NO2) prototype fiber optic sensor utilizing an acid-base indicator that undergoes color changes depending on which gas is present. Bromothymol blue bromocresol green mixture (1/1) in hydrogel (1/1), produces a blue-green indicator for HZ and/or NO2. The sensor was tested several times over a period of eight weeks and the response was cconsistent and proved the feasibility of dual HZ/NO2 leak detection. Prototype sensor construction, the hardware, and the software of the electronic interrogator circuitry are briefly explained. The paper presents a summary of sensor response when exposed to 52 ppm and 18 ppm hydrazine and 400 ppm and 200 ppm nitrogen dioxide.

  6. Collisional energy transfer from excited nitrogen dioxide

    SciTech Connect

    Patten, K.O.

    1991-05-01

    The radiative lifetimes of gaseous nitrogen dioxide excited by pulsed, tunable dye laser radiation are determined for excitation wavelengths ranging from 400 to 750 nm. When the data are expressed in the form of zero-pressure radiative rate constants (k{sub 0}/s{sup {minus}1}), they fit a linear equation with respect to excitation energy. This fit predicts a radiative lifetime of 64 {mu}s for 400 nm excitation and 102 {mu}s at 750 nm. The effects of pressure, observation delay time, and wavelength range of the fluorescence detection apparatus are determined for both radiative lifetime and quenching constant. Dispersed fluorescence spectra from excited nitrogen dioxide are analyzed into three-parameter functions that approximate the corresponding excited state population distributions. Energy transfer from nitrogen dioxide excited at 532 nm and colliding with thirteen buffer gases is studied by this population deconvolution method. The energy removal rate constants increase in the order Ne < Ar < Kr < Xe < He < CO < N{sub 2} < O{sub 2} < NO < NO{sub 2} < CO{sub 2} < SF{sub 6} < SO{sub 2}. The energy transfer rate constant is strongly correlated with the number of degrees of freedom of the buffer molecule and with low vibrational frequencies of the buffer molecule. Population deconvolution from excited nitrogen dioxide fluorescence spectra is again employed to find energy removal rate constants for the NO {sub 2}{sup *}-NO{sub 2} collisions, excited by dye laser at 475.34, 435.04, and 400.00 nm. The energy transfer rate constant increases with decreasing excitation wavelength. The energy removal rate constant between 400 and 532 nm excitation increases as the (3.6 {plus minus} 0.4) power of the excitation photon energy. 76 refs., 67 figs., 16 tabs.

  7. Global Land Use Regression Model for Nitrogen Dioxide Air Pollution.

    PubMed

    Larkin, Andrew; Geddes, Jeffrey A; Martin, Randall V; Xiao, Qingyang; Liu, Yang; Marshall, Julian D; Brauer, Michael; Hystad, Perry

    2017-06-20

    Nitrogen dioxide is a common air pollutant with growing evidence of health impacts independent of other common pollutants such as ozone and particulate matter. However, the worldwide distribution of NO2 exposure and associated impacts on health is still largely uncertain. To advance global exposure estimates we created a global nitrogen dioxide (NO2) land use regression model for 2011 using annual measurements from 5,220 air monitors in 58 countries. The model captured 54% of global NO2 variation, with a mean absolute error of 3.7 ppb. Regional performance varied from R(2) = 0.42 (Africa) to 0.67 (South America). Repeated 10% cross-validation using bootstrap sampling (n = 10,000) demonstrated a robust performance with respect to air monitor sampling in North America, Europe, and Asia (adjusted R(2) within 2%) but not for Africa and Oceania (adjusted R(2) within 11%) where NO2 monitoring data are sparse. The final model included 10 variables that captured both between and within-city spatial gradients in NO2 concentrations. Variable contributions differed between continental regions, but major roads within 100 m and satellite-derived NO2 were consistently the strongest predictors. The resulting model can be used for global risk assessments and health studies, particularly in countries without existing NO2 monitoring data or models.

  8. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  9. 40 CFR 52.1676 - 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...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  10. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  11. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  12. 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 reduction...

  13. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  14. Satellite Mapping of the Earth's Ozone and Sulfur Dioxide

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Total Ozone Mapping Spectrometer (TOMS) instruments are spatially-scanning UV spectrometers that have produced daily global images of total ozone over the last 21 years since the launch of the Nimbus 7 satellite. The instruments use a total ozone retrieval algorithm pioneered by J.V. Dave and C. L. Mateer for the Nimbus 4 Backscatter Ultraviolet (BUV) instrument, designed by D.F. Heath. The TOMS ozone maps have revealed the relations between total ozone and atmospheric dynamics, and shown the dramatic losses of ozone in the Antarctic ozone hole and the Northern hemisphere. The accepted long-term trends in global, regional, and local ozone are derived from data from the Nimbus 7 TOMS and three successive TOMS flights on Russian, Japanese, and American satellites. The next TOMS flight will be launched in 2000. The contiguous mapping design and fortuitous choice of TOMS wavelengths bands also permitted imaging of a second atmospheric gas, sulfur dioxide, which is transient due to its short lifetime. The importance of this measurement was first realized after the eruption of El Chichon volcano in 1982. The extreme range of sizes of volcanic eruptions and the associated danger require observations from a distant observing platform. The first quantitative time series of the input of sulfur dioxide by explosive volcanic eruptions into the atmosphere thus was developed from the TOMS missions. Finally, the Rayleigh and aerosol scattering spectral characteristic and reflectivity complete the four dominant pieces of information in the near UV albedo of the Earth. The four parameters are derived with a linear algorithm, the absorption coefficients of the gases, and effective paths computed from radiative transfer tables. Absorbing aerosol clouds (smoke, dust, volcanic ash) are readily identified by their deviation from a Rayleigh signature. The greatest shortcoming of the TOMS dataset is the 24 hour time resolution that is produced by the polar orbit of the satellite

  15. Satellite Mapping of the Earth's Ozone and Sulfur Dioxide

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin; Bhartia, P. K.

    2000-01-01

    The Total Ozone Mapping Spectrometer (TOMS) instruments are spatially-scanning UV spectrometers that have produced daily global images of total ozone over the last 21 years since the launch of the Nimbus 7 satellite. The instruments use a total ozone retrieval algorithm pioneered by J.V. Dave and C. L. Mateer for the Nimbus 4 Backscatter Ultraviolet (BUV) instrument, designed by D.F. Heath. The TOMS ozone maps have revealed the relations between total ozone and atmospheric dynamics, and shown the dramatic losses of ozone in the Antarctic ozone hole and the Northern hemisphere. The accepted long-term trends in global, regional, and local ozone are derived from data from the Nimbus 7 TOMS and three successive TOMS flights on Russian, Japanese, and American satellites. The next TOMS flight will be launched in 2000. The contiguous mapping design and fortuitous choice of TOMS wavelengths bands also permitted imaging of a second atmospheric gas, sulfur dioxide, which is transient due to its short lifetime. The importance of this measurement was first realized after the eruption of El Chichon volcano in 1982. The extreme range of sizes of volcanic eruptions and the 'associated danger require observations from a distant observing platform. The first quantitative time series of the input of sulfur dioxide by explosive volcanic eruptions into the atmosphere thus was developed from the TOMS missions. Finally, the Rayleigh and aerosol scattering spectral characteristic and reflectivity complete the four dominant pieces of information in the near UV albedo of the Earth. The four parameters are derived with a linear algorithm, the absorption coefficients of the gases, and effective paths computed from radiative transfer tables. Absorbing aerosol clouds (smoke, dust, volcanic ash) are readily identified by their deviation from a Rayleigh signature. The greatest shortcoming of the TOMS dataset is the 24 hour time resolution that is produced by the polar orbit of the satellite

  16. 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.

  17. 77 FR 64244 - Revision to Ambient Nitrogen Dioxide Monitoring Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-19

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 58 RIN 2060-AR59 Revision to Ambient Nitrogen Dioxide Monitoring Requirements AGENCY... deadlines established in the national ambient air quality standard (NAAQS) for nitrogen dioxide (NO 2 ) for...

  18. Ozone disintegration of excess biomass and application to nitrogen removal.

    PubMed

    Park, Ki Young; Lee, Jae Woo; Ahn, Kyu-Hong; Maeng, Sung Kyu; Hwang, Jong Hyuk; Song, Kyung-Guen

    2004-01-01

    A pilot-scale facility integrated with an ozonation unit was built to investigate the feasibility of using ozone-disintegration byproducts of wasted biomass as a carbon source for denitrification. Ozonation of biomass resulted in mass reduction by mineralization as well as by ozone-disintegrated biosolids recycling. Approximately 50% of wasted solids were recovered as available organic matter (ozonolysate), which included nonsettleable microparticles and soluble fractions. Microparticles were observed in abundance at relatively low levels of ozone doses, while soluble fractions became dominant at higher levels of ozone doses in ozone-disintegrated organics. Batch denitrification experiments showed that the ozonolysate could be used as a carbon source with a maximum denitrification rate of 3.66 mg nitrogen (N)/g volatile suspended solids (VSS) x h. Ozonolysate was also proven to enhance total nitrogen removal efficiency in the pilot-scale treatment facility. An optimal chemical oxygen demand (COD)-to-nitrogen ratio for complete denitrification was estimated as 5.13 g COD/g N. The nitrogen-removal performance of the modified intermittently decanted extended aeration process dependent on an external carbon supply could be described as a function of solids retention time.

  19. 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.

  20. 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.

  1. Catalytic Activation of Nitrogen Dioxide for Selective Synthesis of Nitroorganics

    DTIC Science & Technology

    2015-01-15

    AFRL-OSR-VA-TR-2015-0035 Catalytic activation of nitrogen dioxide for selective synthesis SETH BROWN UNIVERSITY OF NOTRE DAME DU LAC Final Report 01...8-98) v Prescribed by ANSI Std. Z39.18 12-01-2015 Final 15 Aug 2011 - 14 Aug 2014 Catalytic activation of nitrogen dioxide for selective synthesis...reductive elimination of the nitroarene has not. Nitrogen dioxide can be used as a source of the nitro group in reactions with arylboronic acids or their

  2. Histological comparisons of white pine needles fumigated with ozone and sulfur dioxide singly and in mixtures

    SciTech Connect

    Boone, G.C.

    1980-01-01

    Needles of Pinus strobus were fumigated with low concentrations of ozone and sulfur dioxide singly and in mixtures for time periods of less than one hour. The needles were killed and fixed immediately after fumigation, cross section 15 microns thick were cut and then stained in a Safranin O-Fast Green stain series. The data revealed that ozone appeared to have a greater initial effect than sulfur dioxide on the tissues of the needles. The sections cut from needles fumigated with sulfur dioxide were similar in appearance to the tissues from nonfumigated control needles. The injury observed in sections of needles fumigated with a mixture of ozone and sulfur dioxide was characteristic of injury caused by ozone rather than sulfur dioxide. Data indicated that fumigations by low concentrations of ozone for a time period of less than one hour could cause changes in the tissues that would be injurious to the normal activities of the needles.

  3. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  4. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  5. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  6. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  7. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  8. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  9. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  10. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  11. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  12. Advantages and disadvantages of chemical oxidation and disinfection by ozone and chlorine dioxide.

    PubMed

    Fiessinger, F; Richard, Y; Montiel, A; Musquere, P

    1981-04-01

    Ozone and chlorine dioxide present definite advantages and disadvantages over chlorination. Chlorination, particularly for the removal of ammonia and the maintenance of a disinfectant residual in the distribution system has decisive advantages and will be difficult to replace. Ozone and chlorine dioxide seem to produce fewer carcinogenic by-products but the risk for acute toxicity, especially from the chlorites which follow chlorine dioxide, is higher than with chlorine. Chlorine dioxide and more particularly ozone should be considered as useful complements to chlorination, but no strong oxidative treatment should be applied before most of the organic matter has been removed.

  13. Study of solar variability impact on nitrogen dioxide: 2004-2013

    NASA Astrophysics Data System (ADS)

    Constantin, Daniel-Eduard; Voiculescu, Mirela; Merlaud, Alexis; Van Roozendael, Michel

    2015-04-01

    Nitrogen dioxide (NO2) locally plays an important role in the radiation budget by absorbing solar radiation at ultraviolet (UV) and visible wavelengths. The influence of solar variability on the inter-annual variability and trends in nitrogen dioxide is evaluated for a period of 10 years (2004-2013) using monthly mean tropospheric NO2 measurements of the Ozone Monitoring Instrument (OMI) version 2.0. Possible signatures of solar variability on nitrogen dioxide time series of NO2 over several cities were analyzed using various statistical methods. Various solar proxies were selected, in order to separate between possible links to solar irradiance and to solar wind. Several locations with different levels of pollution, located in different places of the world (Athens, Jungfraujoch, Lauder, Lisbon, Moscow, and Uccle), were selected. Observations show a clear 27 day period of the NO2 tropospheric Vertical Column Density (VCD) or total Slant Column Density (SCD). NO2 content decreases with increasing activity above polluted areas (e.g. Athens, Moscow) while for unpolluted areas there is no evident correlation (e.g. Lauder, Jungfraujoch). Possible effects of solar wind on NO2 content are observed as well, but the relationship is less clear, since polluted areas seem to respond differently to solar wind variations. The mechanism by which NO2 content can be affected by solar variations relate mainly to ozone production but other paths by which solar energy may be transferred to the lower atmosphere are investigated.

  14. 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 thread...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. Integrated Science Assessment (ISA) for Nitrogen Dioxide (Health Criteria)

    EPA Pesticide Factsheets

    Information, history and background on the development and maintenance of nitrogen dioxide (health criteria) assessments. There is a separate site that has combined NOx/SOx ecological criteria assessment.

  1. 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.

  2. 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.

  3. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    PubMed Central

    Korich, D G; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water. PMID:2339894

  4. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability

    SciTech Connect

    Korich, D.G.; Mead, J.R.; Madore, M.S.; Sinclair, N.A.; Sterling, C.R. )

    1990-05-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.

  5. 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

  6. 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: Nitrogen...

  7. 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: Nitrogen...

  8. 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: Nitrogen...

  9. 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: Nitrogen...

  10. 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: Nitrogen...

  11. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    PubMed Central

    Taylor, Robert H.; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water. PMID:10742264

  12. 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.…

  13. 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.…

  14. INFLUENCE OF ELEVATED OZONE AND CARBON DIOXIDE ON INSECT DENSITIES.

    SciTech Connect

    DELUCIA, E.; DERMODY, O.; O'NEILL, B.; ALDEA, M.; HAMILTON, J.; ZANGERL, A.; ROGER, A.; BERENBAUM, M.

    2005-01-05

    The combustion of fossil fuels is profoundly altering the chemical composition of the atmosphere. Beginning with the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has increased from approximately 280 to 370 {micro}l l{sup -1} in 2004, and it is expected to exceed 550 {micro}l l{sup -1} by 2050. Tropospheric ozone has risen even more rapidly than CO{sub 2} and average summer concentrations in the Northern Hemisphere are expected to continue to increase by 0.5-2.5% per year over the next 30 years. Although elevated CO{sub 2} stimulates photosynthesis and productivity of terrestrial ecosystems, ozone (O{sub 3}) is deleterious. In addition to directly affecting the physiology and productivity of crops, increased concentrations of tropospheric CO{sub 2} and O{sub 3} are predicted to lower the nutritional quality of leaves, which has the potential to increase herbivory as insects eat more to meet their nutritional demands. We tested the hypothesis that changes in tropospheric chemistry affect the relationship between plants and insect herbivores by changing leaf quality. The susceptibility to herbivory of soybean grown in elevated CO{sub 2} or O{sub 3} was examined using free air gas concentration enrichment (SoyFACE). FACE technology has the advantage that plants are cultivated under realistic field conditions with no unwanted alteration of microclimate or artificial constraints on the insect community.

  15. Products of the reaction of hydroxyl radicals with trans-2-butene in the presence of oxygen and nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Martinez, Richard I.; Huie, Robert E.; Herron, John T.

    1980-06-01

    The reactions of hydroxy-substituted alkyl radicals, formed as secondary products in the reaction of ozone with trans-2-butene, have been identified in photoionization mass spectrometry studies, using acetaldehyde and nitrogen dioxide as free-radical scavengers. Products derived from 2-hydroxy-1-methylpropl in the absence of scavengers include 2,3-butanedione (diacetyl), 3-hydroxy-2-butanone (acetoin),and 2,3-butanediol. In the presence of added acetaldehyde or nitrogen dioxide, the formation of these products is suppressed. In addition, with added nitrogen dioxide, new products are formed which have been identified as a series of oxoalkyl and hydroxy-substituted-alkyl nitrates and peroxynitrates. These observations may have an important bearing on the chemistry of photochemical smog.

  16. Nitrogen dioxide exposure and urinary excretion of hydroxyproline and desmosine.

    PubMed

    Adgate, J L; Reid, H F; Morris, R; Helms, R W; Berg, R A; Hu, P C; Cheng, P W; Wang, O L; Muelenaer, P A; Collier, A M

    1992-01-01

    The relationship between average and peak personal exposure to nitrogen dioxide and urinary excretion of hydroxyproline and desmosine was investigated in a population of preschool children and their mothers. Weekly average personal nitrogen dioxide exposures for subjects who resided in homes with one or more potential nitrogen dioxide source (e.g., a kerosene space heater, gas stove, or tobacco smoke) ranged between 16.3 and 50.6 ppb (30.6 and 95.1 micrograms/m3) for children and between 16.9 and 44.1 ppb (12.8 and 82.9 micrograms/m3) for mothers. In these individuals, the hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were unrelated to personal nitrogen dioxide exposure--even though continuous monitoring documented home nitrogen dioxide concentration peaks of 100-475 ppb lasting up to 100 h in duration. Significantly higher hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were observed in children, compared with mothers (p < .001 and .003, respectively).

  17. Nitrogen dioxide exposure and urinary excretion of hydroxyproline and desmosine

    SciTech Connect

    Adgate, J.L.; Reid, H.F.; Morris, R.; Helms, R.W.; Berg, R.A.; Hu, P.C.; Cheng, P.W.; Wang, O.L.; Muelenaer, P.A.; Collier, A.M. )

    1992-09-01

    The relationship between average and peak personal exposure to nitrogen dioxide and urinary excretion of hydroxyproline and desmosine was investigated in a population of preschool children and their mothers. Weekly average personal nitrogen dioxide exposures for subjects who resided in homes with one or more potential nitrogen dioxide source (e.g., a kerosene space heater, gas stove, or tobacco smoke) ranged between 16.3 and 50.6 ppb (30.6 and 95.1 micrograms/m3) for children and between 16.9 and 44.1 ppb (12.8 and 82.9 micrograms/m3) for mothers. In these individuals, the hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were unrelated to personal nitrogen dioxide exposure--even though continuous monitoring documented home nitrogen dioxide concentration peaks of 100-475 ppb lasting up to 100 h in duration. Significantly higher hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were observed in children, compared with mothers (p < .001 and .003, respectively).

  18. 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

  19. IDENTIFICATION OF NEW DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

    EPA Science Inventory

    Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Ozone, chlorine dioxide, and chloramine are currently popular alternatives to ...

  20. IDENTIFICATION OF DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

    EPA Science Inventory

    Many drinking water treatment plants are currently using alternative disinfectants to treat drinking water, with ozone, chlorine dioxide, and chloramine being the most popular. However, compared to chlorine, which has been much more widely studied, there is little information abo...

  1. IDENTIFICATION OF NEW DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

    EPA Science Inventory

    Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Ozone, chlorine dioxide, and chloramine are currently popular alternatives to ...

  2. IDENTIFICATION OF DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

    EPA Science Inventory

    Many drinking water treatment plants are currently using alternative disinfectants to treat drinking water, with ozone, chlorine dioxide, and chloramine being the most popular. However, compared to chlorine, which has been much more widely studied, there is little information abo...

  3. Ozone and carbon dioxide fluxes in a subalpine spruce-fir forest ecosystem

    Treesearch

    Karl Zeller

    1995-01-01

    RMFRES RWU 4452 has made several ozone (O3) and carbon dioxide (CO2) trace gas flux measurements in the Snowy Range, WY GLEES research area over the past few years. These measurements were made using the micrometeorological eddy correlation technique at two sites: one 6 m above tree canopy height on the Brooklyn tower (ozone only); and the other below canopy height, 1-...

  4. 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

  5. High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

    NASA Astrophysics Data System (ADS)

    Lawrence, J. P.; Anand, J. S.; Vande Hey, J. D.; White, J.; Leigh, R. R.; Monks, P. S.; Leigh, R. J.

    2015-11-01

    Nitrogen dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging UV/Vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK on a cloud-free winter day in February 2013. Retrieved NO2 columns gridded to a surface resolution of 80 m × 20 m revealed hotspots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hotspots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

  6. High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

    NASA Astrophysics Data System (ADS)

    Lawrence, J. P.; Anand, J. S.; Vande Hey, J. D.; Leigh, R. R.; Monks, P. S.; Leigh, R. J.

    2015-06-01

    Nitrogen Dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging (UV)-vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK. Retrieved NO2 columns at a surface resolution of 80 m x 20 m revealed hot spots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hot spots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

  7. 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

  8. 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

  9. Reduction of soil carbon formation by tropospheric ozone under increased carbon dioxide levels.

    PubMed

    Loya, Wendy M; Pregitzer, Kurt S; Karberg, Noah J; King, John S; Giardina, Christian P

    2003-10-16

    In the Northern Hemisphere, ozone levels in the troposphere have increased by 35 per cent over the past century, with detrimental impacts on forest and agricultural productivity, even when forest productivity has been stimulated by increased carbon dioxide levels. In addition to reducing productivity, increased tropospheric ozone levels could alter terrestrial carbon cycling by lowering the quantity and quality of carbon inputs to soils. However, the influence of elevated ozone levels on soil carbon formation and decomposition are unknown. Here we examine the effects of elevated ozone levels on the formation rates of total and decay-resistant acid-insoluble soil carbon under conditions of elevated carbon dioxide levels in experimental aspen (Populus tremuloides) stands and mixed aspen-birch (Betula papyrifera) stands. With ambient concentrations of ozone and carbon dioxide both raised by 50 per cent, we find that the formation rates of total and acid-insoluble soil carbon are reduced by 50 per cent relative to the amounts entering the soil when the forests were exposed to increased carbon dioxide alone. Our results suggest that, in a world with elevated atmospheric carbon dioxide concentrations, global-scale reductions in plant productivity due to elevated ozone levels will also lower soil carbon formation rates significantly.

  10. Very Low Energy Electron Scattering from Ozone and Chlorine Dioxide

    NASA Astrophysics Data System (ADS)

    Gulley, R. J.; Field, T. A.; Steer, W. A.; Mason, N. J.; Ziesel, J. P.; Lunt, S. L.; Field, D.

    1998-10-01

    Total cross-sections are reported for the scattering of electrons from ozone (O_3) and chlorine dioxide (OClO) for energies in the range of 9 meV to 10 eV. The measurements were made in transmission experiments using a synchrotron photoionization apparatus with an energy resolution in the incident electron beam of ~ 3.5 meV (FWHM). The cross section for O3 shows strong rotational scattering at low energy, through the presence of the permanent dipole moment of O_3. Superposed on this strong scattering signal, there is evidence of a weak structure around 50 meV associated with dissociative attachment. A shape resonance, known from earlier work at ~ 4 meV, is also observed. Electron scattering from OClO is dominated by rotationally inelastic scattering decreasing from a peak at essentially zero eV to an energy of 40 meV, where p-wave attachment becomes more important, peaking at 50--60 meV and extending to several hundred meV.

  11. Fact Sheets and Additional Information Regarding the 2012 Decision to Retain the Secondary NAAQS for Nitrogen Dioxide and Sulfur Dioxide

    EPA Pesticide Factsheets

    On April 3, 2012, EPA sdecided to retain the current secondary national ambient air quality standard (NAAQS) for nitrogen dioxide (NO2) and sulfur dioxide (SO2).This page contains a fact sheet describing that action.

  12. 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.

  13. Testing of Colorimetric Tubes for Nitrogen Dioxide and Monomethylhydrazine.

    ERIC Educational Resources Information Center

    Diamond, Philip

    Colorimetric tubes for nitrogen dioxide (NO2) and monomethylhydrazine (MMH) were tested for accuracy and results indicate that at the levels checked the tubes' average deviation was plus or minus 20 percent. Tube NO2 concentrations all read lower than the analyzed concentrations. MMH tubes read much higher than the analyzed concentration of 0.28…

  14. 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.

  15. 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... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide...

  16. 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... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide...

  17. 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... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide...

  18. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide...

  19. 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... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide...

  20. Internal energy distributions from nitrogen dioxide fluorescence. 2. Collisional energy transfer from excited nitrogen dioxide

    SciTech Connect

    Patten, K.O. Jr.; Johnston, H.S. Lawrence Berkeley Lab., CA )

    1993-09-30

    We follow the collisional deactivation of laser-excited nitrogen dioxide through its dispersed fluorescence. The energy acceptor gases are NO[sub 2] at four excitation energies ranging from 18828 to 24989 cm[sup [minus]1] and five monatomic gases, four diatomic gases, and three polyatomic gases with 18828-cm[sup [minus]1] excitation energy. The nominal products are the shapes of the internal energy distributions, which are obtained and plotted for several representative cases. From these distributions, the first three moments of the internal energy distributions are derived as a function of molecular collisions and tabulated as (i) the average internal energy, (ii) energy spread, and (iii) skewness. These quantities are plotted against c(M)t, the product of buffer gas concentration c(M) and delay time after laser excitation t(0.5-2 [mu]s), which is a quantity proportional to number of collisions. The negative slope of average energy vs c(M)t is the macroscopic energy-transfer rate constant, k[sub [epsilon

  1. 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.

  2. Global Ozone and Reactive Nitrogen : Composition, Chemistry and Sources

    NASA Technical Reports Server (NTRS)

    Sing, Hanwant B.; Bradshaw, J.; Davis, D.; Gregory, G.; Talbot, R.

    1994-01-01

    Ozone plays a central role in the chemistry of the atmosphere both as an ultraviolet shield and as a source of hydroxyl radicals (OH), a potent initiator of atmospheric chemistry. There is evidence to suggest that the ozone abundance in the troposphere (0-10 km) has doubled since the industrial revolution and continues to increase to date. The principle reason for this increase is thought to be the increasing emissions of nitrogen oxides (NO(x)) from anthropogenic activities. Although NO(x) is highly reactive and its products such as HN03 are easily removed by deposition, it now appears that its chemistry is quite complex and it can be transported over long distances via its conversion to a variety of nitrates and penetrates. The sources of atmospheric NO(x) include free tropospheric sources such as lightning and subsonic aircraft, as well as surface emissions which are transported to the free troposphere via convective processes. Recent experimental and theoretical studies have tried to unravel the chemistry of reactive nitrogen species, its sources, and their role in ozone formation. In this presentation we shall describe the results from these studies.

  3. Global Ozone and Reactive Nitrogen : Composition, Chemistry and Sources

    NASA Technical Reports Server (NTRS)

    Sing, Hanwant B.; Bradshaw, J.; Davis, D.; Gregory, G.; Talbot, R.

    1994-01-01

    Ozone plays a central role in the chemistry of the atmosphere both as an ultraviolet shield and as a source of hydroxyl radicals (OH), a potent initiator of atmospheric chemistry. There is evidence to suggest that the ozone abundance in the troposphere (0-10 km) has doubled since the industrial revolution and continues to increase to date. The principle reason for this increase is thought to be the increasing emissions of nitrogen oxides (NO(x)) from anthropogenic activities. Although NO(x) is highly reactive and its products such as HN03 are easily removed by deposition, it now appears that its chemistry is quite complex and it can be transported over long distances via its conversion to a variety of nitrates and penetrates. The sources of atmospheric NO(x) include free tropospheric sources such as lightning and subsonic aircraft, as well as surface emissions which are transported to the free troposphere via convective processes. Recent experimental and theoretical studies have tried to unravel the chemistry of reactive nitrogen species, its sources, and their role in ozone formation. In this presentation we shall describe the results from these studies.

  4. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment...

  5. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT...

  6. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment...

  7. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment...

  8. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT...

  9. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT...

  10. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment...

  11. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT...

  12. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT...

  13. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment...

  14. Reactivity of natural organic matter fractions with chlorine dioxide and ozone.

    PubMed

    Swietlik, J; Dabrowska, A; Raczyk-Stanisławiak, U; Nawrocki, J

    2004-02-01

    The effects of ozone and chlorine dioxide on the aquatic natural organic matter (NOM) were studied. The natural as well as oxidised organic matter in aerated and sand filtered water were fractionated using XAD, anion-exchange, and cation-exchange resins procedure into humic acid, hydrophobic acids and neutrals, and hydrophilic acids, bases and neutrals. The main NOM components were hydrophobic, while oxidation with both ozone and chlorine dioxide increased the proportion of hydrophilic fractions. High-pressure size exclusion chromatography with UV-254 nm and UV-220 nm detection was used to determine the differences between molecular weight distribution of natural and oxidised organic matter fractions. The main purpose of this paper was to compare the reactivity of individual NOM fractions with oxidants in order to compare the productivity of biodegradable by-products after oxidation with chlorine dioxide and ozone. The quantity as well as the quality of by-products were analysed by means of ion and gas chromatography.

  15. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Profile § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If...

  16. 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.

  17. 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.

  18. 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.

  19. Spatially resolved measurements of nitrogen dioxide in an urban environment using concurrent multi-axis differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Leigh, R. J.; Corlett, G. K.; Frieß, U.; Monks, P. S.

    2006-12-01

    A novel system using the technique of concurrent multi-axis differential optical absorption spectroscopy system has been developed and applied to the measurement of nitrogen dioxide in an urban environment. Using five fixed telescopes, slant columns of nitrogen dioxide, ozone, water vapour, and the oxygen dimer, O4, are simultaneously retrieved in five vertically separated viewing directions. The application of this remote sensing technique in the urban environment is explored. Through, the application of several simplifying assumptions a tropospheric concentration of NO2 is derived and compared with an urban background in-situ chemiluminescence detector. The remote sensing and in-situ techniques show good agreement. Owing to the high time resolution of the measurements, the ability to image and quantify plumes within the urban environment is demonstrated. The CMAX-DOAS measurements provide a useful measure of overall NO2 concentrations on a city-wide scale.

  20. Spatially resolved measurements of nitrogen dioxide in an urban environment using concurrent multi-axis differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Leigh, R. J.; Corlett, G. K.; Frieß, U.; Monks, P. S.

    2007-09-01

    A novel system using the technique of concurrent multi-axis differential optical absorption spectroscopy system has been developed and applied to the measurement of nitrogen dioxide in an urban environment. Using five fixed telescopes, slant columns of nitrogen dioxide, ozone, water vapour, and the oxygen dimer, O4, are simultaneously retrieved in five vertically separated viewing directions. The application of this remote sensing technique in the urban environment is explored. Through the application of several simplifying assumptions a tropospheric concentration of NO2 is derived and compared with an urban background in-situ chemiluminescence detector. Trends derived from remote sensing and in-situ techniques show agreement to within 15 to 40% depending on conditions. Owing to the high time resolution of the measurements, the ability to image and quantify plumes within the urban environment is demonstrated. The CMAX-DOAS measurements provide a useful measure of overall NO2 concentrations on a city-wide scale.

  1. Treatment of Ammonia Nitrogen Wastewater in Low Concentration by Two-Stage Ozonization.

    PubMed

    Luo, Xianping; Yan, Qun; Wang, Chunying; Luo, Caigui; Zhou, Nana; Jian, Chensheng

    2015-09-23

    Ammonia nitrogen wastewater (about 100 mg/L) was treated by two-stage ozone oxidation method. The effects of ozone flow rate and initial pH on ammonia removal were studied, and the mechanism of ammonia nitrogen removal by ozone oxidation was discussed. After the primary stage of ozone oxidation, the ammonia removal efficiency reached 59.32% and pH decreased to 6.63 under conditions of 1 L/min ozone flow rate and initial pH 11. Then, the removal efficiency could be over 85% (the left ammonia concentration was lower than 15 mg/L) after the second stage, which means the wastewater could have met the national discharge standards of China. Besides, the mechanism of ammonia removal by ozone oxidation was proposed by detecting the products of the oxidation: ozone oxidation directly and ·OH oxidation; ammonia was mainly transformed into NO₃(-)-N, less into NO₂(-)-N, not into N₂.

  2. 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 control...

  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 control...

  4. 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 control...

  5. 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 control...

  6. 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 control...

  7. Ozone production using dielectric barrier discharge in oxygen and carbon dioxide

    NASA Astrophysics Data System (ADS)

    Pontiga, Francisco; Abidat, Roukia; Moreno, Helena; Agustín, Fernández-Rueda; Rebiaï, Saida

    2015-09-01

    The generation of ozone in oxygen and carbon dioxide using a planar dielectric barrier discharge (DBD) has been experimentally investigated. The DBD reactor was operated at moderate voltages (4.2 to 5.6 kV) and frequencies (50 to 500 Hz) and the gas flow rate was varied in the range 50 to 200 cm3/min. The averaged consumed power (<1 W) was evaluated using a monitor capacitor of known capacitance (1 μF). The effluent gas from the DBD reactor was diverted to a gas cell situated inside the sample compartment of a UV spectrophotometer. Therefore, ozone concentration was determined from the measurement of absorbance using Beer-Lambert law. The results have shown that ozone concentration in oxygen grows very linearly with the input power. In contrast, the production of ozone in carbon dioxide is less regular, which may be due to the deposition of a thin layer over the stainless steel electrode during the application of the electrical discharge. Moreover, the rate of ozone production with the injected energy density was found to be 500 times weaker in carbon dioxide than in pure oxygen. This work was supported by the Spanish Government Agency ``Ministerio de Ciencia e Innovación'' under Contract No. FIS2011-25161.

  8. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    Treesearch

    Alan F. Talhelm; Kurt S. Pregitzer; Mark E. Kubiske; Donald R. Zak; Courtney E. Campany; Andrew J. Burton; Richard E. Dickson; George R. Hendrey; J. G. Isebrands; Keith F. Lewin; John Nagy; David F. Karnosky

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment...

  9. Growth responses of Populus tremuloides clones to interacting elevated carbon dioxide and tropospheric ozone

    Treesearch

    J. G. Isebrands; E. P. McDonald; E. Kruger; G. Hendrey; K. Percy; K. Pregitzer; J. Sober; D. F. Karnosky

    2001-01-01

    The Intergovernmental Panel of Climate Change (IPCC) has concluded that the greenhouse gases carbon dioxide (CO2) and tropospheric ozone (O3) are increasing concomitantly globally. Little is known about the effect of these interacting gases on growth, survival, and productivity of forest ecosystems. In this study we assess...

  10. Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone

    Treesearch

    Kurt Pregitzer; Wendy Loya; Mark Kubiske; Donald Zak

    2006-01-01

    The aspen free-air CO2 and O3 enrichment (FACTS II-FACE) study in Rhinelander, Wisconsin, USA, is designed to understand the mechanisms by which young northern deciduous forest ecosystems respond to elevated atmospheric carbon dioxide (CO2) and elevated tropospheric ozone (O3)...

  11. Effects of ozone and sulfur dioxide on height and stem specific gravity of Populus hybrids

    Treesearch

    Roy L. Patton

    1981-01-01

    Unfumigated hybrid poplars (Populus spp.) were compared with poplars of the same nine clones fumigated with 0.15 pprn ozone or 0.25 ppm sulfur dioxide. After 102 days, plant height and stem specific gravity were measured to determine whether specific gravity is altered by the fumigants and to compare that response to height suppression, an accepted...

  12. Modeling forest ecosystem responses to elevated carbon dioxide and ozone using artificial neural networks.

    PubMed

    Larsen, Peter E; Cseke, Leland J; Miller, R Michael; Collart, Frank R

    2014-10-21

    Rising atmospheric levels of carbon dioxide and ozone will impact productivity and carbon sequestration in forest ecosystems. The scale of this process and the potential economic consequences provide an incentive for the development of models to predict the types and rates of ecosystem responses and feedbacks that result from and influence of climate change. In this paper, we use phenotypic and molecular data derived from the Aspen Free Air CO2 Enrichment site (Aspen-FACE) to evaluate modeling approaches for ecosystem responses to changing conditions. At FACE, it was observed that different aspen clones exhibit clone-specific responses to elevated atmospheric levels of carbon dioxide and ozone. To identify the molecular basis for these observations, we used artificial neural networks (ANN) to examine above and below-ground community phenotype responses to elevated carbon dioxide, elevated ozone and gene expression profiles. The aspen community models generated using this approach identified specific genes and subnetworks of genes associated with variable sensitivities for aspen clones. The ANN model also predicts specific co-regulated gene clusters associated with differential sensitivity to elevated carbon dioxide and ozone in aspen species. The results suggest ANN is an effective approach to predict relevant gene expression changes resulting from environmental perturbation and provides useful information for the rational design of future biological experiments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. 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.

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

    SciTech Connect

    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

  15. 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.

  16. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    NASA Astrophysics Data System (ADS)

    Foley, Theresa

    The Clean Air Act of 1970 was promulgated after thousands of lives were lost in four catastrophic air pollution events. It authorized the establishment of National Ambient Air Quality Standards or (NAAQS) for six pollutants that are harmful to human health and welfare: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone and sulfur dioxide. The Clean Air Act also led to the establishment of the United Stated Environmental Protection Agency (US EPA) to set and enforce regulations. The first paper in this dissertation studies ozone in the Lake Michigan region (Foley, T., Betterton, E.A., Jacko, R., Hillery, J., 2011. Lake Michigan air quality: The 1994-2003 LADCO Aircraft Project (LAP). Atmospheric Environment 45, 3192-3202.) The Chicago-Milwaukee-Gary metropolitan area has been unable to meet the ozone NAAQS since the Clean Air Act was implemented. The Lake Michigan Air Directors' Consortium (LADCO) hypothesized that land breezes transport ozone precursor compounds over the lake, where a large air/water temperature difference creates a shallow conduction layer, which is an efficient reaction chamber for ozone formation. In the afternoon, lake breezes and prevailing synoptic winds then transport ozone back over the land. To further evaluate this hypothesis, LADCO sponsored the 1994-2003 LADCO Aircraft Project (LAP) to measure the air quality over Lake Michigan and the surrounding areas. This study has found that the LAP data supports this hypothesis of ozone formation, which has strong implications for ozone control strategies in the Lake Michigan region. The second paper is this dissertation (Foley, T., Betterton, E.A., Wolf, A.M.A., 2012. Ambient PM10 and metal concentrations measured in the Sunnyside Unified School District, Tucson, Arizona. Journal of the Arizona-Nevada Academy of Science, 43, 67-76) evaluated the airborne concentrations of PM10 (particulate matter with an aerodynamic diameter of 10 microns or less) and eight metalloids and metals

  17. Reactive nitrogen oxides and ozone above a taiga woodland

    NASA Astrophysics Data System (ADS)

    Bakwin, Peter S.; Jacob, Daniel J.; Wofsy, Steven C.; Munger, J. William; Daube, Bruce C.; Bradshaw, John D.; Sandholm, Scott T.; Talbot, Robert W.; Singh, Hanwant B.; Gregory, Gerald L.; Blake, Donald R.

    1994-01-01

    Measurements of reactive nitrogen oxides (NOx and NOy) and ozone (O3) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Artie Boundary Layer Expedition (ABLE) 3B. Levels of nitrogen oxides and O3 were strongly modulated by the synoptic scale meteorology that brought air from various source regions to the site. Industrial pollution from the Great Lakes region of the U.S. and Canada appears to be a major source for periodic elevation of NOx, NOy and O3. We find that NO/NO2 ratios at this site at midday were approximately 50% those expected from a simple photochemical steady state between NOx and O3, in contrast to our earlier results from the ABLE 3A tundra site. The difference between the taiga and tundra sites is likely due to much larger emissions of biogenic hydrocarbons (particularly isoprene) from the taiga vegetation. Hydrocarbon photooxidation leads to relatively rapid production of peroxy radicals, which convert NO to NO2, at the taiga site. Ratios of NOx to NOy were typically 2-3 times higher in the PBL during ABLE 3B than during ABLE 3 A. This is probably the result of high PAN levels and suppressed formation of HNO3 from NO2 due to high levels of biogenic hydrocarbons at the ABLE 3B site.

  18. Reactive nitrogen oxides and ozone above a taiga woodland

    NASA Technical Reports Server (NTRS)

    Bakwin, Peter S.; Jacob, Daniel J.; Wofsy, Steven C.; Munger, J. William; Daube, Bruce C.; Bradshaw, John D.; Sandholm, Scott T.; Talbot, Robert W.; Singh, Hanwant B.; Gregory, Gerald L.

    1994-01-01

    Measurements of reactive nitrogen oxides (NO(x) and NO(y)) and ozone (O3) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Artic Boundary Layer Expedition (ABLE) 3B. Levels of nitrogen oxides and O3 were strongly modulated by the synoptic scale meteorology that brought air from various source regions to the site. Industrial pollution from the Great Lakes region of the U.S. and Canada appears to be a major source for periodic elevation of NO(x), and NO(y) and O3. We find that NO/NO2 ratios at this site at midday were approximately 50% those expected from a simple photochemical steady state between NO(x) and O3, in contrast to our earlier results from the ABLE 3A tundra site. The difference between the taiga and tundra sites is likely due to much larger emissions of biogenic hydrocarbons (particularly isoprene) from the taiga vegetation. Hydrocarbon photooxidation leads to relatively rapid production of peroxy radicals, which convert NO to NO2, at the taiga site. Ratios of NO(x) to NO(y) were typically 2-3 times higher in the PBL during ABLE 3B than during ABLE 3A. This is probably the result of high PAN levels and suppressed formation of HNO3 from NO2 due to high levels of biogenic hydrocarbons at the ABLE 3B site.

  19. International comparison CCQM-K76: Sulfur dioxide in nitrogen

    NASA Astrophysics Data System (ADS)

    Guenther, Franklin R.; Kelley, Michael E.; Mitchell, Gerald D.; de Jesús Avila Salas, Manuel; Koelliker Delgado, Jorge; Rangel Murillo, Francisco; Serrano Caballero, Victor M.; Pérez Castorena, Alejandro; Shinji, Uehara; Ciecior, Dariusz; Smarçaro da Cunha, Valnei; Rodrigues Augusto, Cristiane; Cipriano Ribeiro, Claudia; de Lima Fioravante, Andreia; Dias, Florbela; Sang-Hyub, Oh; Macé, Tatiana; Sutour, Christophe; Büki, Tamás; Qiao, Han; Botha, Angelique; Mogale, David M.; Tshilongo, James; Ntsasa, Napo; Mphamo, Tshepiso; Uprichard, Ian; Milton, Martin; Vargha, Gergely; Brookes, Chris; Johri, Prabha; Valkova, Miroslava; Konopelko, Leonid; Kustikov, Yury; Pankratov, V. V.; Rumyantsev, D. V.; Pavlov, M. V.; Gromova, E. V.; van der Veen, Adriaan; van Otterloo, Peter; Wessel, Rob M.

    2011-01-01

    The key comparison CCQM-K76 was designed to test the capabilities of the participants to measure and certify sulfur dioxide in nitrogen, and to provide supporting evidence for the CMCs of these institutes for sulfur dioxide. Also, as sulfur dioxide is designated a core compound, and the 100 µmol/mol concentration is within the designated core compound concentration range, this comparison was also designed to demonstrate core capabilities of institutes which qualify under the rules of the Gas Analysis Working Group. The results of all 16 participants in this key comparison, except for three, are consistent with their key comparisons reference values. The three participants which are outside the KCRV interval are NIM, SMU and NPLI. This comparison may be used to demonstrate core analytical capabilities in accordance with the rules and procedures of the CCQM Gas Analysis Working group. 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 provisions of the CIPM Mutual Recognition Arrangement (MRA).

  20. Elevated Carbon Dioxide and Ozone Concentrations Alter Soybean Antioxidant Metabolism

    USDA-ARS?s Scientific Manuscript database

    One important mechanism by which plants sense and respond to their environment is through redox control. Oxidative damage at the cellular level can feed forward to decrease leaf photosynthesis and therefore canopy and ecosystem productivity. How rising atmospheric carbon dioxide (CO2) and tropospher...

  1. Reactive nitrogen oxides and ozone above a taiga woodland

    SciTech Connect

    Bakwin, P.S.; Jacob, D.J.; Wofsy, S.C.; Munger, J.W.; Daube, B.C.; Bradshaw, J.D.; Sandholm, S.T.; Talbot, R.W.; Singh, H.B.; Gregory, G.L.

    1994-01-20

    Measurements of reactive nitrogen oxides (NO{sub x} and NO{sub y}) and ozone (O{sub 3}) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Arctic Boundary Layer Expedition (ABLE) 3B. Levels of nitrogen oxides and O{sub 3} were strongly modulated by the synoptic scale meteorology that brought air from various regions to the site. Industrial pollution from the Great Lakes region of the US and Canada appears to be a major source for periodic elevation of NO{sub x}, NO{sub y} and O{sub 3}. We find that NO/NO{sub 2} ratios at this site at midday were approximately 50% those expected from a simple photochemical steady state between NO{sub x} and O{sub 3}, in contrast to our earlier results from the ABLE 3A tundra site. The difference between the taiga and tundra sites is likely due to much larger emissions of biogenic hydrocarbons (particularly isoprene) from the taiga vegetation. Hydrocarbon photooxidation leads to relatively rapid production of peroxy radicals, which convert NO to NO{sub 2}, at the taiga site. Ratios of NO{sub x} to NO{sub y} were typically 2-3 times higher in the PBL during ABLE 3B than during ABLE 3A. This is probably the result of high PAN levels and suppressed formation of HNO{sub 3} from NO{sub 2} due to high levels of biogenic hydrocarbons at the ABLE 3B site. 36 refs., 7 figs., 3 tabs.

  2. Effects of acute exposure to nitrogen dioxide on primary antibody response

    SciTech Connect

    Hidekazu, F.; Fujio, S.

    1981-01-01

    The effects of acute exposure to nitrogen dioxide on primary humoral antibody response to sheep red blood cells in mice were studied. Mice were exposed to 5 ppm, 20 ppm, and 40 ppm nitrogen dioxide for 12 hr. An exposure of 20 ppm or 40 ppm resulted in a significant suppression of antibody responses, but 5 ppm did not affect antibody response. This immunosuppression resulting from nitrogen dioxide exposure was more apparent in males than females. Exposures to 20 ppm nitrogen dioxide for various time intervals revealed that the strongest suppression effect was observed in the group exposed 2 days after antigen injection. A decreased total cell number in the spleen, and more strikingly, in the thymus, was also caused by acute exposure to nitrogen dioxide.

  3. Effects of acute exposure to nitrogen dioxide on primary antibody response

    SciTech Connect

    Hidekazu, F.; Fujio, S.

    1981-05-01

    The effects of acute exposure to nitrogen dioxide on primary humoral antibody response to sheep red blood cells in mice were studied. Mice were exposed to 5 ppM, 20 ppM, and 40 ppM nitrogen dioxide for 12 h. An exposure of 20 ppM or 40 ppM resulted in a significant suppression of antibody responses, but 5 ppM did not affect antibody response. This immunosuppression resulting from nitrogen dioxide exposure was more apparent in males than females. Exposures to 20 ppM nitrogen dioxide for various time intervals revealed that the strongest suppression effect was observed in the group exposed 2 days after antigen injection. A decreased total cell number in the spleen, and more strikingly, in the thymus, was also caused by acute exposure to nitrogen dioxide.

  4. Atmosphere-Biosphere Exchange of Methane, Carbon Dioxide, and Ozone

    NASA Astrophysics Data System (ADS)

    Fan, Song-Miao

    1991-02-01

    The atmosphere-biosphere exchange was measured for CO_2 and O_3 in a tropical rain forest in the wet season of 1987, and for CO_2, CH_4 , and O_3 in a subarctic tundra in summer 1988. Photosynthesis and respiration were found to be in approximate balance in the rain forest. Net ecosystem uptake of CO_2 in the forest increased with intensity of light in the range of measurements. It is suggested that photosynthesis of a well-watered forest is primarily controlled by photosynthetically active radiation. Changes in the distribution of cloud cover, associated for example with El Nino, might induce globally significant changes in primary productivity and carbon storage. Soil moisture controls in tundra the distribution and association of vegetation types and the atmosphere -biosphere exchange of CO_2, although light intensity also influences the daily and seasonal net exchange of CO_2. Methane fluxes from the subarctic tundra averaged 25 +/- 1 (SE) mgCH_4/m ^2/d, representing 6 percent the net uptake of carbon for the 30 days of measurement. Wet meadow tundra emitted CH_4 at rates substantially higher than upland tundra. Lakes and lake margins are important sources of methane; lake emissions were dependent on surface wind speed. A global methane emission from tundra ecosystems is estimated to be ~ 11 megatons CH_4 per year based on this measurement, a small fraction (~ 3%) of the global source. Ozone deposition fluxes averaged ~ 1.0 times 10^ {11} molecules cm^{ -2}s^{-1} in the tropical forest and in the arctic tundra, similar in magnitude to the estimated mean stratospheric input. Ozone deposition fluxes were proportional to O_3 concentrations in the surface layer and regulated by turbulent transport and stomatal activity. Day-time ozone concentrations and deposition velocities measured at ~10 m above canopy averaged ~5 ppb and 1.8 cm s^ {-1} over the tropical forest and ~25 ppb and 0.25 cm s^{ -1} over the subarctic tundra, respectively. These results imply that

  5. Reactive nitrogen partitioning and its relationship to winter ozone events in Utah

    NASA Astrophysics Data System (ADS)

    Wild, R. J.; Edwards, P. M.; Bates, T. S.; Cohen, R. C.; de Gouw, J. A.; Dubé, W. P.; Gilman, J. B.; Holloway, J.; Kercher, J.; Koss, A.; Lee, L.; Lerner, B.; McLaren, R.; Quinn, P. K.; Roberts, J. M.; Stutz, J.; Thornton, J. A.; Veres, P. R.; Warneke, C.; Williams, E.; Young, C. J.; Yuan, B.; Brown, S. S.

    2015-08-01

    High wintertime ozone levels have been observed in the Uintah Basin, Utah, a sparsely populated rural region with intensive oil and gas operations. The reactive nitrogen budget plays an important role in tropospheric ozone formation. Measurements were taken during three field campaigns in the winters of 2012, 2013, and 2014, which experienced varying climatic conditions. Average concentrations of ozone and total reactive nitrogen were observed to be 2.5 times higher in 2013 than 2012, with 2014 an intermediate year in most respects. However, photochemically active NOx(NO+NO2), remained remarkably similar all three years. Roughly half of the more oxidized forms of nitrogen were composed of nitric acid in 2013, with nighttime nitric acid formation through heterogeneous uptake of N2O5 contributing approximately 6 times more than daytime formation. The nighttime N2O5 lifetime between the high-ozone year 2013 and the low-ozone year 2012 is lower by a factor 2.6, and much of this is due to higher aerosol surface area in the high ozone year of 2013. A box-model simulation supports the importance of nighttime chemistry on the reactive nitrogen budget, showing a large sensitivity of NOx and ozone concentrations to nighttime processes.

  6. Cryogenic Adsorption of Nitrogen and Carbon Dioxide in Activated Carbon

    NASA Astrophysics Data System (ADS)

    Shen, Fuzhi; Liu, Huiming; Xu, Dong; Zhang, Hengcheng; Lu, Junfeng; Li, Laifeng

    2017-09-01

    Activated carbon have been used for a long time at low temperature for cryogenic applications. The knowledge of adsorption characteristics of activated carbon at cryogenic temperature is essential for some specific applications. However, such experimental data are very scare in the literature. In order to measure the adsorption characteristics of activated carbon under variable cryogenic temperatures, an adsorption measurement device was presented. The experiment system is based on the commercially available PCT-pro adsorption analyzer coupled to a two-stage Gifford McMahon refrigerator, which allows the sample to be cooled to 4.2K. Cryogenic environment can be maintained steadily without the cryogenic liquid through the cryocooler and temperature can be controlled precisely between 5K and 300K by the temperature controller. Adsorption measurements were performed in activated carbon for carbon dioxide and nitrogen and the adsorption isotherm were obtained.

  7. High resolution nitrogen dioxide observations: retrieval, evaluation, and interpretation

    NASA Astrophysics Data System (ADS)

    Lamsal, L. N.; Janz, S. J.; Krotkov, N. A.; Pickering, K. E.; Kowalewski, M. G.; Loughner, C.; Spurr, R. J. D.; Crawford, J. H.

    2015-12-01

    The Airborne Compact Atmospheric Mapper (ACAM) deployed during the DISCOVER-AQ Maryland field campaign made hyperspectral remote sensing measurements in the 304-910 nm range allowing observations of several tropospheric pollutants including nitrogen dioxide (NO2) at an unprecedented spatial resolution of 1.5x0.75 km2. We apply the DOAS method, include high resolution information for surface reflectivity and vertical distributions of NO2 and aerosols, and account for temporal variation in atmospheric NO2 to retrieve lower tropospheric NO2 column. We compare NO2 from ACAM with observations from in-situ aircraft, ground-based PANDORA, and space-based OMI, and NO2 simulation from air quality models. The high resolution ACAM measurements offer not only new insights into our understanding of atmospheric composition and chemistry through observation of sub-sampling variability in typical satellite and model resolutions, but also opportunities for algorithm improvements for upcoming geostationary air quality missions.

  8. 40 CFR Appendix F to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) F Appendix...—Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) Principle and Applicability 1. Atmospheric concentrations of nitrogen dioxide...

  9. Sighting of el chichon sulfur dioxide clouds with the nimbus 7 total ozone mapping spectrometer.

    PubMed

    Krueger, A J

    1983-06-24

    The eruptions of El Chichón volcano on 28 March and 3 and 4 April 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nanometers). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 meters per second. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on 3 and 4 April is 3.3 x 10(6) tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.

  10. Sighting of El Chichon sulfur dioxide clouds with the Nimbus 7 total ozone mapping spectrometer

    NASA Technical Reports Server (NTRS)

    Krueger, A. J.

    1983-01-01

    The eruptions of El Chichon volcano on March 28 and April 3 and 4, 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nm). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 m/sec. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on April 3 and 4 is 3.3 million tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.

  11. Sighting of El Chichon sulfur dioxide clouds with the Nimbus 7 total ozone mapping spectrometer

    SciTech Connect

    Krueger, A.J.

    1983-06-24

    The eruptions of El Chichon volcano on 28 March and 3 and 4 April 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong adsorption by volcanic gases at the shortest wavelenghts of the spectrometer (312.5 and 317.5 nanometers). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 meters per second. The spectral reflectance is consistent with sulfur dioxide adsorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on 3 and 4 April is 3.3 x 10/sup 6/ tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.

  12. Sighting of El Chichon sulfur dioxide clouds with the Nimbus 7 total ozone mapping spectrometer

    SciTech Connect

    Krueger, A.J.

    1983-06-24

    The eruptions of El Chichon volcano on 28 March and 3 and 4 April 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nanometers). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 meters per second. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on 3 and 4 April is 3.3x10/sup 6/ tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.

  13. Reactive nitrogen partitioning and its relationship to winter ozone events in Utah

    NASA Astrophysics Data System (ADS)

    Wild, R. J.; Edwards, P. M.; Bates, T. S.; Cohen, R. C.; de Gouw, J. A.; Dubé, W. P.; Gilman, J. B.; Holloway, J.; Kercher, J.; Koss, A. R.; Lee, L.; Lerner, B. M.; McLaren, R.; Quinn, P. K.; Roberts, J. M.; Stutz, J.; Thornton, J. A.; Veres, P. R.; Warneke, C.; Williams, E.; Young, C. J.; Yuan, B.; Zarzana, K. J.; Brown, S. S.

    2016-01-01

    High wintertime ozone levels have been observed in the Uintah Basin, Utah, a sparsely populated rural region with intensive oil and gas operations. The reactive nitrogen budget plays an important role in tropospheric ozone formation. Measurements were taken during three field campaigns in the winters of 2012, 2013 and 2014, which experienced varying climatic conditions. Average concentrations of ozone and total reactive nitrogen were observed to be 2.5 times higher in 2013 than 2012, with 2014 an intermediate year in most respects. However, photochemically active NOx (NO + NO2) remained remarkably similar all three years. Nitric acid comprised roughly half of NOz ( ≡ NOy - NOx) in 2013, with nighttime nitric acid formation through heterogeneous uptake of N2O5 contributing approximately 6 times more than daytime formation. In 2012, N2O5 and ClNO2 were larger components of NOz relative to HNO3. The nighttime N2O5 lifetime between the high-ozone year 2013 and the low-ozone year 2012 is lower by a factor of 2.6, and much of this is due to higher aerosol surface area in the high-ozone year of 2013. A box-model simulation supports the importance of nighttime chemistry on the reactive nitrogen budget, showing a large sensitivity of NOx and ozone concentrations to nighttime processes.

  14. Elevated ozone and nitrogen deposition affect nitrogen pools of subalpine grassland.

    PubMed

    Bassin, Seraina; Käch, David; Valsangiacomo, Alain; Mayer, Jochen; Oberholzer, Hans-Rudolf; Volk, Matthias; Fuhrer, Jürg

    2015-06-01

    In a free-air fumigation experiment with subalpine grassland, we studied long-term effects of elevated ozone (O3) and nitrogen (N) deposition on ecosystem N pools and on the fate of anthropogenic N. At three times during the seventh year of exposure, N pools and recovery of a stable isotope tracer ((15)N) were determined in above- and belowground plant parts, and in the soil. Plants were much better competitors for (15)N than soil microorganisms. Plant N pools increased by 30-40% after N addition, while soil pools remained unaffected, suggesting that most of the extra N was taken up and stored in plant biomass, thus preventing the ecosystem from acquiring characteristics of eutrophication. Elevated O3 caused an increase of N in microbial biomass and in stabilized soil N, probably resulting from increased litter input and lower litter quality. Different from individual effects, the interaction between the pollutants remained partly unexplained.

  15. 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.

  16. 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

  17. Responses of surface ozone air quality to anthropogenic nitrogen deposition in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zhao, Yuanhong; Zhang, Lin; Tai, Amos P. K.; Chen, Youfan; Pan, Yuepeng

    2017-08-01

    Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. Here we combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model, CLM) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by the addition of atmospheric deposited nitrogen - namely, emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index, LAI, in the model), could increase surface ozone from increased biogenic VOC emissions (e.g., a 6.6 Tg increase in isoprene emission), but it could also decrease ozone due to higher ozone dry deposition velocities (up to 0.02-0.04 cm s-1 increases). Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations shows general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate- and land-use-driven surface ozone changes at regional scales and partly offset the surface ozone reductions due to land use changes reported in previous studies

  18. Interaction of ozone and carbon dioxide with polycrystalline potassium bromide and its atmospheric implication

    NASA Astrophysics Data System (ADS)

    Levanov, Alexander V.; Isaikina, Oksana Ya.; Maksimov, Ivan B.; Lunin, Valerii V.

    2017-03-01

    It has been discovered for the first time that gaseous ozone in the presence of carbon dioxide and water vapor interacts with crystalline potassium bromide giving gaseous Br2 and solid salts KHCO3 and KBrO3. Molecular bromine and hydrocarbonate ion are the products of one and the same reaction described by the stoichiometric equation 2KBr(cr.) + O3(gas) + 2CO2(gas) + H2O(gas) → 2KHCO3(cr.) + Br2(gas) + O2(gas). The dependencies of Br2, KHCO3 and KBrO3 formation rates on the concentrations of O3 and CO2, humidity of initial gas mixture, and temperature have been investigated. A kinetic scheme has been proposed that explains the experimental regularities found in this work on the quantitative level. According to the scheme, the formation of molecular bromine and hydrocarbonate is due to the reaction between hypobromite BrO-, the primary product of bromide oxidation by ozone, with carbon dioxide and water; bromate results from consecutive oxidation of bromide ion by ozone Br- → +O3 , -O2 BrO- → +O3 , -O2 BrO2- → +O3, -O2 BrO3- .

  19. 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.

  20. Surface modification of nitrogen-doped carbon nanotubes by ozone via atomic layer deposition

    SciTech Connect

    Lushington, Andrew; Liu, Jian; Tang, Yongji; Li, Ruying; Sun, Xueliang

    2014-01-15

    The use of ozone as an oxidizing agent for atomic layer deposition (ALD) processes is rapidly growing due to its strong oxidizing capabilities. However, the effect of ozone on nanostructured substrates such as nitrogen-doped multiwalled carbon nanotubes (NCNTs) and pristine multiwalled carbon nanotubes (PCNTs) are not very well understood and may provide an avenue toward functionalizing the carbon nanotube surface prior to deposition. The effects of ALD ozone treatment on NCNTs and PCNTs using 10 wt. % ozone at temperatures of 150, 250, and 300 °C are studied. The effect of ozone pulse time and ALD cycle number on NCNTs and PCNTs was also investigated. Morphological changes to the substrate were observed by scanning electron microscopy and high resolution transmission electron microscopy. Brunauer-Emmett-Teller measurements were also conducted to determine surface area, pore size, and pore size distribution following ozone treatment. The graphitic nature of both NCNTs and PCNTs was determined using Raman analysis while x-ray photoelectron spectroscopy (XPS) was employed to probe the chemical nature of NCNTs. It was found that O{sub 3} attack occurs preferentially to the outermost geometric surface of NCNTs. Our research also revealed that the deleterious effects of ozone are found only on NCNTs while little or no damage occurs on PCNTs. Furthermore, XPS analysis indicated that ALD ozone treatment on NCNTs, at elevated temperatures, results in loss of nitrogen content. Our studies demonstrate that ALD ozone treatment is an effective avenue toward creating low nitrogen content, defect rich substrates for use in electrochemical applications and ALD of various metal/metal oxides.

  1. Stratospheric nitrogen dioxide in Antarctic regions from ground based and satellite observations during 2001

    NASA Astrophysics Data System (ADS)

    Bortoli, Daniele; Giovanelli, Giorgio; Ravegnani, Fabrizio; Kostadinov, Ivan K.; Petritoli, Andrea; Calzolari, Francescopiero; Costa, Maria J.; Silva, Ana M.

    2003-04-01

    The application of Differential Optical Absorption Spectroscopy (DOAS) methodology to the zenith scattered light data collected with the GASCOD spectrometer developed at the ISAC Institute allow for the detection of stratospheric trace gases involved in the ozone cycle such as NO2, OClO, BrO. The instrument was installed in December 1995 in the Italian Antarctic station at Terra Nova Bay (74°26'S, 164°03E', Ross Sea), after several tests both in laboratory and in Antarctic region, for unattended and continuous measurement in extreme high-latitude environment. The GASCOD is still working and producing very interesting data for the study of the denitrification processes during the formation of the so-called ozone hole over the Antarctic region. For the continuous NO2 monitoring for whole the year, also during winter when the station is unmanned, the [407 - 460] nm spectral region is investigated. The results for Nitrogen Dioxide, obtained by application of DOAS algorithms to the data recorded during the year 2001, are presented. ERS-2 was launched in April 1995 into a near-polar sun-synchronous orbit at a mean altitude of 795 km. The descending node crosses the equator at 10:30 local time. GOME is a nadir-scanning double monochromator covering the 237 nm to 794 nm wavelength range with a spectral resolution of 0.17-0.33 nm. The spectrum is split into four spectral channels, each recorded quasi-simultaneously by a 1024-pixel photodiode array. The global spatial coverage is obtained within 3 days at the equator by a 960 km across-track swath (4.5 s forward scan, 1.5 s back scan). The ground pixel size of the measurements is 320 X 40 km2. A comparison of GASCOD and GOME results for NO2 total column is performed.

  2. Nitrogen-assisted Three-phase Equilibrium in Hydrate Systems Composed of Water, Methane, Carbon Dioxide, and Nitrogen

    NASA Astrophysics Data System (ADS)

    Darnell, K.; Flemings, P. B.; DiCarlo, D. A.

    2016-12-01

    Guest molecule exchange is a new and promising methane hydrate production technique in which methane gas is produced by injection of another gas without requiring depressurization or thermal stimulation. The technique is generally associated with injection of carbon dioxide, but injection of nitrogen and carbon dioxide mixtures are the most efficient and economical. However, thermodynamic behavior of injection mixtures is poorly understood, and it is unclear how nitrogen affects the exchange process. Here, we describe thermodynamic stability of hydrate systems that contain water, methane, carbon dioxide, and nitrogen. We present a series of ternary and quaternary phase diagrams and show the impact nitrogen has on hydrate stability. Our results demonstrate that nitrogen can either stabilize hydrate, de-stabilize hydrate, or produce three-phase equilibrium (gas, water, and hydrate) depending on its relative abundance. At low abundance nitrogen forms hydrate and directly contributes to the exchange process. At high abundance nitrogen de-stabilizes hydrate akin to traditional hydrate inhibitors, such as salt, alcohol, or mono-ethylene glycol. We show how the dual properties of nitrogen lead to three-phase equilibrium and how three-phase equilibrium may explain much of the behavior observed in methane production from nitrogen-rich injections. We apply our analysis to laboratory experiments and the methane hydrate field test on the northern Alaskan slope at Ignik Sikumi. These results can be extended to analyze dynamic evolution of mixed hydrate systems.

  3. Treatment of Ammonia Nitrogen Wastewater in Low Concentration by Two-Stage Ozonization

    PubMed Central

    Luo, Xianping; Yan, Qun; Wang, Chunying; Luo, Caigui; Zhou, Nana; Jian, Chensheng

    2015-01-01

    Ammonia nitrogen wastewater (about 100 mg/L) was treated by two-stage ozone oxidation method. The effects of ozone flow rate and initial pH on ammonia removal were studied, and the mechanism of ammonia nitrogen removal by ozone oxidation was discussed. After the primary stage of ozone oxidation, the ammonia removal efficiency reached 59.32% and pH decreased to 6.63 under conditions of 1 L/min ozone flow rate and initial pH 11. Then, the removal efficiency could be over 85% (the left ammonia concentration was lower than 15 mg/L) after the second stage, which means the wastewater could have met the national discharge standards of China. Besides, the mechanism of ammonia removal by ozone oxidation was proposed by detecting the products of the oxidation: ozone oxidation directly and ·OH oxidation; ammonia was mainly transformed into NO3−-N, less into NO2−-N, not into N2. PMID:26404353

  4. Effects of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone on Phytochemical Composition of Trembling Aspen ( Populus tremuloides ) and Paper Birch ( Betula papyrifera ).

    PubMed

    Couture, John J; Meehan, Timothy D; Rubert-Nason, Kennedy F; Lindroth, Richard L

    2017-01-01

    Anthropogenic activities are altering levels of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3). These changes can alter phytochemistry, and in turn, influence ecosystem processes. We assessed the individual and combined effects of elevated CO2 and O3 on the phytochemical composition of two tree species common to early successional, northern temperate forests. Trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) were grown at the Aspen FACE (Free-Air Carbon dioxide and ozone Enrichment) facility under four combinations of ambient and elevated CO2 and O3. We measured, over three years (2006-08), the effects of CO2 and O3 on a suite of foliar traits known to influence forest functioning. Elevated CO2 had minimal effect on foliar nitrogen and carbohydrate levels in either tree species, and increased synthesis of condensed tannins and fiber in aspen, but not birch. Elevated O3 decreased nitrogen levels in both tree species and increased production of sugar, condensed tannins, fiber, and lignin in aspen, but not birch. The magnitude of responses to elevated CO2 and O3 varied seasonally for both tree species. When co-occurring, CO2 offset most of the changes in foliar chemistry expressed under elevated O3 alone. Our results suggest that levels of CO2 and O3 predicted for the mid-twenty-first century will alter the foliar chemistry of northern temperate forests with likely consequences for forest community and ecosystem dynamics.

  5. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    PubMed Central

    Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3. Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r2 = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m−2) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (ΔNPP/ΔN) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2. Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. PMID:24604779

  6. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests.

    PubMed

    Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

    2014-08-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2 ) and tropospheric ozone (O3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3 . Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r(2) = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m(-2) ) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆NPP/∆N) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2 . Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

  7. 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.

  8. Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

    PubMed

    Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

    2007-08-01

    As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

  9. Table of Historical Nitrogen Dioxide National Ambient Air Quality Standards (NAAQS)

    EPA Pesticide Factsheets

    See the history of limits to the level of nitrogen dioxide (NO2) in ambient air, set through the NAAQS review and rulemaking process under the Clean Air Act. This includes both primary and secondary standards.

  10. 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

  11. Nitrogen Dioxide Promotes Allergic Sensitization to Inhaled Antigen

    PubMed Central

    Bevelander, Mieke; Mayette, Jana; Whittaker, Laurie A.; Paveglio, Sara A.; Jones, Christine C.; Robbins, Justin; Hemenway, David; Akira, Shizuo; Uematsu, Satoshi; Poynter, Matthew E.

    2015-01-01

    Allergen sensitization and allergic airway disease are likely to come about through the inhalation of Ag with immunostimulatory molecules. However, environmental pollutants, including nitrogen dioxide (NO2), may promote adaptive immune responses to innocuous Ags that are not by themselves immunostimulatory. We tested in C57BL/6 mice whether exposure to NO2, followed by inhalation of the innocuous protein Ag, OVA, would result in allergen sensitization and the subsequent development of allergic airway disease. Following challenge with aerosolized OVA alone, mice previously exposed via inhalation to NO2 and OVA developed eosinophilic inflammation and mucus cell metaplasia in the lungs, as well as OVA-specific IgE and IgG1, and Th2-type cytokine responses. One hour of exposure to 10 parts per million NO2 increased bronchoalveolar lavage fluid levels of total protein, lactate dehydrogenase activity, and heat shock protein 70; promoted the activation of NF-κB by airway epithelial cells; and stimulated the subsequent allergic response to Ag challenge. Furthermore, features of allergic airway disease were not induced in allergen-challenged TLR2−/− and MyD88−/− mice exposed to NO2 and aerosolized OVA during sensitization. These findings offer a mechanism whereby allergen sensitization and asthma may result under conditions of high ambient or endogenous NO2 levels. PMID:17785804

  12. Nitrogen dioxide exposure and airway responsiveness in individuals with asthma.

    PubMed

    Brown, James S

    2015-01-01

    Controlled human exposure studies evaluating the effect of inhaled nitrogen dioxide (NO2) on the inherent responsiveness of the airways to challenge by broncho-constricting agents have had mixed results. In general, existing meta-analyses show statistically significant effects of NO2 on the airway responsiveness of individuals with asthma. However, no meta-analysis has provided a comprehensive assessment of the clinical relevance of changes in airway responsiveness, the potential for methodological biases in the original papers, and the distribution of responses. This paper provides analyses showing that a statistically significant fraction (i.e. 70% of individuals with asthma exposed to NO2 at rest) experience increases in airway responsiveness following 30-min exposures to NO2 in the range of 200 to 300 ppb and following 60-min exposures to 100 ppb. The distribution of changes in airway responsiveness is log-normally distributed with a median change of 0.75 (provocative dose following NO2 divided by provocative dose following filtered air exposure) and geometric standard deviation of 1.88. About a quarter of the exposed individuals experience a clinically relevant reduction in their provocative dose due to NO2 relative to air exposure. The fraction experiencing an increase in responsiveness was statistically significant and robust to exclusion of individual studies. Results showed minimal change in airway responsiveness for individuals exposed to NO2 during exercise.

  13. Detection of nitrogen dioxide by CW cavity-enhanced spectroscopy

    NASA Astrophysics Data System (ADS)

    Jie, Guo; Han, Ye-Xing; Yu, Zhi-Wei; Tang, Huai-Wu

    2016-11-01

    In the paper, an accurate and sensitive system was used to monitor the ambient atmospheric NO2 concentrations. This system utilizes cavity attenuated phase shift spectroscopy(CAPS), a technology related to cavity ring down spectroscopy(CRDS). Advantages of the CAPS system include such as: (1) cheap and easy to control the light source, (2) high accuracy, and (3) low detection limit. The performance of the CAPS system was evaluated by measuring of the stability and response of the system. The minima ( 0.08 ppb NO2) in the Allan plots show the optimum average time( 100s) for optimum detection performance of the CAPS system. Over a 20-day-long period of the ambient atmospheric NO2 concentrations monitoring, a comparison of the CAPS system with an extremely accurate and precise chemiluminescence-based NOx analyzer showed that the CAPS system was able to reliably and quantitatively measure both large and small fluctuations in the ambient nitrogen dioxide concentration. The experimental results show that the measuring instrument results correlation is 0.95.

  14. Determinants of nitrogen dioxide concentrations in indoor ice skating rinks.

    PubMed Central

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

    1998-01-01

    OBJECTIVES: The combination of poor ventilation and fuel-powered ice resurfacers has resulted in elevated nitrogen dioxide (NO2) concentrations in many indoor ice skating rinks. This study examined the factors influencing concentrations and the effects of various engineering controls in ice rinks with different resurfacer fuels. METHODS: Indoor NO2 concentrations were measured in 19 enclosed ice skating rinks over 3 winters by means of passive samplers, with 1-week average measurements during the first winter pilot study and single-day working-hour measurements in the final 2 winters. Personal exposures to drivers also were assessed during the last winter. RESULTS: Rinks in which propane-fueled resurfacers were used had a daily mean indoor NO2 concentration of 206 ppb, compared with 132 ppb for gasoline-fueled and 37 ppb for electric-powered resurfacers. Engineering controls, such as increased ventilation and resurfacer tuning, reduced NO2 concentrations by 65% on average, but outcomes varied widely, and concentrations increased in subsequent months. CONCLUSIONS: Electric ice resurfacers, increased ventilation, or emission control systems are recommended to protect the health of workers and patrons, with surveillance programs proposed to track implementation and maintain an observer effect. PMID:9842374

  15. Nitrogen dioxide compromises defence functions of the airway epithelium.

    PubMed

    Kakinoki, Y; Ohashi, Y; Tanaka, A; Washio, Y; Yamada, K; Nakai, Y; Morimoto, K

    1998-01-01

    The effect of nitrogen dioxide (NO2) exposure on airway epithelial defence functions, such as ciliary activity, mucociliary transport velocity and junctional barrier function, remains to be elucidated. Our study investigates the effect of 24-h exposure to 3.0 ppm of NO2 on the airway epithelial defence functions in the healthy rabbit. Fifty-two healthy rabbits were exposed to 3.0 ppm of NO2 (NO2 group) or pure air (control group) for 24 successive hours in exposure chambers. After completion of the exposure sequence, the ciliary activity in the trachea was examined by a photoelectric method, the mucociliary transport velocity in the trachea by an endoscopic method and epithelial permeability of the trachea to fluorescein isothiocyanate-dextrans (FD-70s; molecular weight: 70,000 daltons) by an in vitro tracheal sac method. In the NO2 group, all epithelial defence functions, including ciliary activity, mucociliary transport velocity and epithelial permeability were significantly inferior to those in the control group. Although there was considerable overlap in the parameters examined between the two groups, approximately two-thirds of the animals were susceptible to 24-h exposure to 3 ppm of NO2. Dysfunction of both the junctional barrier and the mucociliary system could allow easier entry of allergen molecules to the airway parenchyma, where immunocomponent cells exist. NO2 might be involved to some extent in the clinical manifestation of airway allergic disorders through epithelial dysfunction.

  16. Effect of nitrogen dioxide on human nasal epithelium

    SciTech Connect

    Carson, J.L.; Collier, A.M.; Hu, S.C.; Delvin, R.B. )

    1993-09-01

    The nasal epithelium of young adult white men in good health was evaluated by electron microscopy in a condition blind fashion relative to exposures of 2 ppm nitrogen dioxide (NO2) or clean air for 4 h. The exposure protocol involved two separate exposures of the same individuals to NO2 or clean air approximately 3 wk apart. We found qualitative and quantitative evidence that luminal border membranes of ciliated cells were ultrastructurally altered in six of seven samples of nasal epithelium obtained following NO2 exposures, although subsequent morphometric statistical analyses were not significant. This alteration was characterized by cilia containing excess matrix in which individual or, more commonly, multiple ciliary axonemes were embedded, and by vesiculations of luminal border ciliary membranes, a pattern less common in clean air-exposed control specimens. Although these patterns were not widespread, their morphology was consistent with findings of previous animal studies involving acute and chronic exposure to NO2. Our findings suggest that adverse effects on mucociliary function in normal humans due to acute exposure to low levels of NO2 are most likely minimal. However, in view of other reports of NO2 exposure in laboratory animals documenting ciliary injury, our observations support a view that similar patterns might appear more prominently with higher NO2 levels and/or more extended exposure intervals.

  17. Study of ozone and sulfur dioxide using Thailand based Brewer Spectrophotometers

    NASA Astrophysics Data System (ADS)

    Kumharn, Wilawan; Sudhibrabha, Sumrid

    2014-03-01

    Ozone (O3) and sulfur dioxide (SO2) in a vertical column of the atmosphere in Thailand were obtained from the Brewers#121 and #120. There are similarities between the O3 patterns obtained from the two sites, which are higher in the summer and rainy season compared with winter, although the magnitude of the change in Bangkok is greater than that in Songkhla. SO2 values showed the summer months provide the higher SO2 values in Bangkok, in contrast to Songkhla where the summer months give lower SO2 values.

  18. 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.

  19. Quenching of nitrogen dioxide fluorescence excited by a He-Cd laser

    SciTech Connect

    Kireev, S.V.; Shnyrev, S.L.

    1994-06-01

    The effect of some buffer gases on nitrogen dioxide fluorescence excited by a 0.44-{mu}m He-Cd laser is investigated. The rate constants of fluorescence self-quenching by buffer gases are measured. The cross sections of collision quenching of fluorescence are determined. The obtained results can be used for nitrogen dioxide monitoring in the atmosphere. 12 refs., 3 figs., 1 tab.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Carbon dioxide capture with the ozone-like polynitrogen molecule Li3N3.

    PubMed

    Torrent-Sucarrat, Miquel; Varandas, António J C

    2014-12-26

    In a very recent article (Chem.-Eur. J. 2014, 20, 6636), Olson et al. performed a theoretical study of the low-lying isomers of Li3N3 and found that two of the most stable structures show a novel N3(3-) molecular motif, which possesses structural and chemical bonding features similar to ozone. We explore a first application of these new Li3N3 species as a captor of carbon dioxide. Our results conclude that this is a very exothermic and exoergic process (the capture of one and two carbon dioxide molecules on Li3N3 releases, respectively, 42 and 70 kcal mol(-1) in relative free energy values evaluated at the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level of theory), which apparently occurs without any energy barrier but requires a nonlinear N3(3-) molecular motif.

  5. The creation of pollution mapping and measurement of ambient concentration of sulfur dioxide and nitrogen dioxide with passive sampler.

    PubMed

    Akdemir, Andaç

    2014-01-01

    Measurements of nitrogen and sulfur dioxide using passive sampler over 12 months in Samsun, Turkey, are compared with SO2 and NO2 concentrations obtained from a co-located chemiluminescence analyzer. The concentrations of Sulfur and nitrogen dioxide in the ambient air during the period from November 2009 to September 2010 are analyzed. The highest value for annual NO2 and SO2 averages of passive sampler was 29.65 μg/m(3) and 21.01 μg/m(3) for exposures of 2-weeks at an industrial site. The maximum monthly concentration for SO2 was observed at the 10(th) measurement station with 44.19 μg/m(3) for August. The maximum monthly concentration for NO2 was observed on the 3(rd) measurement station with 42.83 μg/m(3) for November. A negative correlation between nitrogen dioxide concentrations and temperature (R(2) = -0.5489) was estimated. A positive correlation between nitrogen dioxide measurement with passive sampler and continuous measurement (R(2) = 0.6571) was estimated.

  6. The creation of pollution mapping and measurement of ambient concentration of sulfur dioxide and nitrogen dioxide with passive sampler

    PubMed Central

    2014-01-01

    Background Measurements of nitrogen and sulfur dioxide using passive sampler over 12 months in Samsun, Turkey, are compared with SO2 and NO2 concentrations obtained from a co-located chemiluminescence analyzer. The concentrations of Sulfur and nitrogen dioxide in the ambient air during the period from November 2009 to September 2010 are analyzed. Results The highest value for annual NO2 and SO2 averages of passive sampler was 29.65 μg/m3 and 21.01 μg/m3 for exposures of 2-weeks at an industrial site. The maximum monthly concentration for SO2 was observed at the 10th measurement station with 44.19 μg/m3 for August. The maximum monthly concentration for NO2 was observed on the 3rd measurement station with 42.83 μg/m3 for November. A negative correlation between nitrogen dioxide concentrations and temperature (R2 = −0.5489) was estimated. A positive correlation between nitrogen dioxide measurement with passive sampler and continuous measurement (R2 = 0.6571) was estimated. PMID:25136451

  7. Pulmonary response to threshold levels of sulfur dioxide (1. 0 ppm) and ozone (0. 3 ppm) (journal version)

    SciTech Connect

    Folinsbee, L.J.; Bedi, J.F.; Horvath, S.M.

    1985-01-01

    The authors exposed 22 healthy adult non-smoking men for 2 hours to either filtered air, 1.0 ppm sulfur dioxide, 0.30 ppm ozone, or the combination of 1.0 ppm sulfur dioxide plus 0.30 ppm ozone. It was hypothesized that exposure to near-threshold concentrations of these pollutants would show any interaction between the two pollutants that might have been masked by the more-obvious response to the higher concentrations of ozone used in previous studies. Each subject alternated 30-minute treadmill exercise with 10-minute rest periods for the 2 hours. Following ozone exposure alone, forced expiratory measurements (FVC, FEV-1, and FEF25-75%) were significantly decreased. The combined exposure to SO/sub 2/ plus O/sub 3/ produced similar but smaller decreases in these measures. There were small but significant differences between the ozone and the ozone plus sulfur dioxide exposure for FVC, FEV-1,-2,-3, and FEF25-75% at the end of the 2-hour exposure. It was concluded that, with these pollutant concentrations, there is no additive or synergistic effect of the two pollutants on pulmonary function.

  8. Modeling of recovery mechanism of ozone zero phenomenaby adding small amount of nitrogen in atmospheric pressure oxygen dielectric barrier discharges

    NASA Astrophysics Data System (ADS)

    Akashi, Haruaki; Yoshinaga, Tomokazu

    2013-09-01

    Ozone zero phenomena in an atmospheric pressure oxygen dielectric barrier discharges have been one of the major problems during a long time operation of ozone generators. But it is also known that the adding a small amount of nitrogen makes the recover from the ozone zero phenomena. To make clear the mechanism of recovery, authors have been simulated the discharges with using the results of Ref. 3. As a result, the recovery process can be seen and ozone density increased. It is found that the most important species would be nitrogen atoms. The reaction of nitrogen atoms and oxygen molecules makes oxygen atoms which is main precursor species of ozone. This generation of oxygen atoms is effective to increase ozone. The dependence of oxygen atom density (nO) and nitrogen atom density (nN) ratio was examined in this paper. In the condition of low nN/nO ratio case, generation of nitrogen oxide is low, and the quenching of ozone by the nitrogen oxide would be low. But in the high ratio condition, the quenching of ozone by nitrogen oxide would significant. This work was supported by KAKENHI(23560352).

  9. Ecosystem-scale trade-offs between impacts of ozone and reactive nitrogen

    NASA Astrophysics Data System (ADS)

    Rowe, Ed; Hayes, Felicity; Sawicka, Kasia; Mills, Gina; Jones, Laurence; Moldan, Filip; Sereina, Bassin; van Dijk, Netty; Evans, Chris

    2015-04-01

    Nitrogen (N) deposition stimulates plant productivity in many terrestrial ecosystems. This is clearly beneficial for production agriculture and forestry, but increased litterfall and decreased ground-level light availability reduce the suitability of habitats for many biota (Jones et al., 2014). This mechanism (Hautier et al., 2009), together with the acidifying effects of N (Stevens et al., 2010), has caused considerable biodiversity loss at global scale. Ozone, by contrast, has the effect of reducing plant production, and a simple assessment would suggest that this might mitigate the effects of N pollution. We explored the interactions between ozone and nitrogen at mechanistic level using a version of the MADOC model (Rowe et al., 2014) modified to include effects of ozone. The model was tested against data from long-term monitoring and experimental sites with a focus on nitrogen and/or ozone effects. Effects on biodiversity were assessed by coupling the MADOC model to the MultiMOVE plant species model. We used this model-chain to explore trade-offs and synergies between the impacts of nitrogen and ozone on biodiversity and ecosystem biogeochemistry. In a review of the effects of ozone on ecosystem processes, two consistent effects were found: decreased net primary production due to damage to photosynthetic mechanisms; and an increase in litter nitrogen apparently caused by interference of ozone with the retranslocation process (Mills, in prep.). Insufficient evidence was found to justify inclusion of posited interactive mechanisms such as increased ozone susceptibility with greater nitrogen supply. However, the MADOC model illustrated emergent ozone-nitrogen interactions at ecosystem scale, for example an increase in N leaching due to decreased plant demand and greater litter N content. Empirical evidence for interactive effects of nitrogen and ozone at ecosystem scale is severely lacking, but simulated results were consistent with soil and soil solution

  10. Carbon dioxide in the atmosphere: isotopic exchange with ozone and its use as a tracer in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Lee, A. Y.; Irion, F. W.; DeMore, W. B.; Wen, J.

    1997-01-01

    Atmospheric heavy ozone is enriched in the isotopes 18O and 17O. The magnitude of this enhancement, of the order of 100%, is very large compared with that commonly known in atmospheric chemistry and geochemistry. The heavy oxygen atom in heavy ozone is therefore useful as a tracer of chemical species and pathways that involve ozone or its derived products. As a test of the isotopic exchange reactions, we successfully carry out a series of numerical experiments to simulate the results of the laboratory experiments performed by Wen and Thiemens [1993] on ozone and CO2. A small discrepancy between the experimental and the model values for 17O exchange is also revealed. The results are used to compute the magnitude of isotopic exchange between ozone and carbon dioxide via the excited atom O(1D) in the middle atmosphere. The model for 18O is in good agreement with the observed values.

  11. Carbon dioxide in the atmosphere: isotopic exchange with ozone and its use as a tracer in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Lee, A. Y.; Irion, F. W.; DeMore, W. B.; Wen, J.

    1997-01-01

    Atmospheric heavy ozone is enriched in the isotopes 18O and 17O. The magnitude of this enhancement, of the order of 100%, is very large compared with that commonly known in atmospheric chemistry and geochemistry. The heavy oxygen atom in heavy ozone is therefore useful as a tracer of chemical species and pathways that involve ozone or its derived products. As a test of the isotopic exchange reactions, we successfully carry out a series of numerical experiments to simulate the results of the laboratory experiments performed by Wen and Thiemens [1993] on ozone and CO2. A small discrepancy between the experimental and the model values for 17O exchange is also revealed. The results are used to compute the magnitude of isotopic exchange between ozone and carbon dioxide via the excited atom O(1D) in the middle atmosphere. The model for 18O is in good agreement with the observed values.

  12. Evaluation of injury to expanded and expanding leaves of peas exposed to sulfur dioxide and ozone

    SciTech Connect

    Olszyk, D.M.; Tibbitts, T.W.

    1982-03-01

    Necrosis, chlorophyll concentration, dry weight and surface area measurements were made to evaluate injury to leaves of Pisum sativum L. cv Alsweet grown under controlled environments and exposed to sulfur dioxide, ozone and combinations of sulfur dioxide plus ozone. Injury evaluations were made at low pollutant levels causing slight necrotic injury and high levels causing severe necrotic injury. At low levels, expanded leaves with a trace of necrotic injury had a 10% reduction in chlorophyll concentration but no reductions in dry weight or surface area, while expanding leaves, also with a trace of necrotic injury, had a reduction in chlorophyll concentration accompanied by reductions in dry weight and surface area. At high pollutant levels, expanded leaves with severe necrotic injury had a 70% reduction in chlorophyll concentration and significant reductions in dry weight and surface area, while expanding leaves had a smaller amount of necrotic injury and a smaller reduction in chlorophyll concentration, but reductions in dry weight and surface area similar to those in expanded leaves. Thus, the following measurements are proposed as reliable indicators of injury at pollutant concentrations just above the threshold for injury: chlorophyll concentration for expanded leaves and surface area for expanding leaves. Reliable indicators of injury at higher concentrations causing serious injury to leaves are: necrosis for expanded leaves and chlorophyll concentration, dry weight, and surface area for expanding leaves. 19 references, 4 figures, 3 tables.

  13. 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.

  14. 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.

  15. Degradation of nitrogen containing organic compounds by combined photocatalysis and ozonation.

    PubMed

    Klare, M; Waldner, G; Bauer, R; Jacobs, H; Broekaert, J A

    1999-04-01

    The combination of TiO2-assisted photocatalysis and ozonation in the degradation of nitrogen-containing substrates such as alkylamines, alkanolamines, heterocyclic and aromatic N-compounds has been investigated. A laboratory set-up was designed and the influence of the structure of the N-compound, the TiO2 and ozone concentration on the formation of breakdown products were examined. The experimental results showed that a considerable increase in the degradation efficiency of the N-compounds is obtained by a combination of photocatalysis and ozonation as compared to either ozonation or photocatalysis only. The mineralization of the model substances was monitored by measurements of the TOC and ion-chromatographic determinations of the formed NO2- and NO3-. The temporal changes of concentrations of breakdown products, such as NH4+, short chain alkyl- and alkanolamines were determined by single column ion chromatography (SCIC) and as well as by electrospray mass spectrometry (EI-MS).

  16. 40 CFR Appendix F to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) F Appendix...—Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) Principle and Applicability 1. Atmospheric concentrations of nitrogen...

  17. Influence of ozone and nitrogen deposition on bark beetle activity under drought conditions

    Treesearch

    Michele Eatough Jones; Timothy D. Paine; Mark E. Fenn; Mark A. Poth

    2004-01-01

    Four years of severe drought from 1999 through 2003 led to unprecedented bark beetle activity in ponderosa and Jeffrey pine in the San Bernardino and San Jacinto Mountains of southern California. Pines in the San Bernardino Mountains also were heavily impacted by ozone and nitrogenous pollutants originating from urban and agricultural areas in the Los Angeles basin. We...

  18. Air pollution and watershed research in the central Sierra Nevada of California: nitrogen and ozone

    Treesearch

    Carolyn Hunsaker; Andrzej Bytnerowicz; Jessica Auman; Ricardo Cisneros

    2007-01-01

    Maintaining healthy forests is the major objective for the Forest Service scientists and managers working for the U.S. Department of Agriculture. Air pollution, specifically ozone (O3) and nitrogenous (N) air pollutants, may severely affect the health of forest ecosystems in the western U.S. Thus, the monitoring of air pollution concentration and...

  19. Effects of sulfur dioxide and ozone on yield and quality of potatoes: Final report

    SciTech Connect

    Pell, E.J.; Pearson, N.S.; Vinten-Johansen, C.; McGruer, G.; Yang, Y.

    1989-01-01

    The objectives of this project were to develop an outdoor fumigation facility designed to expose plants to ozone (O3) and sulfur dioxide (SO2) and to conduct experiments that would examine the impact of the two gases alone and in combination on field grown potato plants. Two systems of dispensing and monitoring pollutants were contrasted, one using miniature solenoid valves and the other using critical orifices. Both systems provided excellent pollutant control. The orifices were relatively inexpensive and required less maintenance than did the solenoid valve system. Two field experiments were conducted, one in 1985 and and the other in 1986. Potato plants were exposed to charcoal filtered air, nonfiltered air, nonfiltered air supplemented with O3 at levels which resulted in 1.33, 1.66 or 1.99 times ambient O3 concentrations or charcoal filtered air plus 0.14, 0.28 or 0.56 ppM SO2. There were additional treatments combining the two pollutant regimes. Ozone induced a linear reduction in yield reflected by decreases in weight and number of tubers > 6.35 cm in diameter. In general effects on number and weight of smaller tubers were not detected. Ozone also induced a decrease in the percent dry matter and reducing sugar content of potato tubers. Sulfur dioxide affected number of Grade One tubers in both years and percent dry matter and sucrose content in 1986 only. While dose-response curves for all SO2 effects fit quadratic curves the impact of SO2 doses used in these experiments were stimulatory. No important interactions were observed between O3 and SO2. 36 refs., 5 figs., 31 tabs.

  20. 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

  1. The effect of carbon-nitrogen coupling on the reduced land carbon sink caused by tropospheric ozone

    NASA Astrophysics Data System (ADS)

    KvalevâG, Maria Malene; Myhre, Gunnar

    2013-06-01

    ozone is known to have a damaging effect on carbon uptake in the terrestrial biosphere. We show that limitations of available nitrogen for sufficient plant growth reduce the negative impact of tropospheric ozone on carbon uptake in plants, leading to a smaller indirect change in radiative forcing than previously calculated. Transient climate simulations between 1900 and 2004 where plant growth is affected by tropospheric ozone have been performed by the National Center for Atmospheric Research Community Land Model with and without a coupling to the nitrogen cycle. When the land model includes nitrogen limitation on plant growth, the negative effect from tropospheric ozone on carbon uptake in plants is reduced by up to a factor of four compared to model simulation without nitrogen limitation. Only 2-5% of the radiative forcing from CO2 between 1900 and 2004 can be attributed to the indirect effect of tropospheric ozone which is a factor of six lower than results from previous studies.

  2. 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.

  3. Effects of elevated nitrogen dioxide and carbon dioxide on the growth of Sugar Maple and Hemlock seedlings

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; McGuire, K. L.; Sparks, J. P.

    2005-12-01

    The partial pressure of nitrogen dioxide (NO2) in the earth's atmosphere has been rising since the industrial revolution and is likely to continue rising due to the burning of fossil fuels. When NO2 enters plant leaves, it can undergo reactions that produce nitrate, which can be a source of nutrient nitrogen for the plant. However, NO2 is also an oxidant with the potential to damage cell membranes and decrease growth. The goals of this study were to examine the effect of NO2 on plant productivity alone and in combination with elevated CO2 under both nitrogen- and non-nitrogen-limiting conditions. To assess these effects, we conducted CO2, NO2, and CO2 + NO2 fumigations of sugar maple and eastern hemlock seedlings in open-topped chambers and measured relative growth rate, specific leaf area, root:shoot, and C:N of the leaves, stems, and roots. Sugar maple growth was reduced by 7% under elevated NO2 when nitrogen was limiting. When nitrogen was not limiting and CO2 was ambient, elevated NO2 caused a 4% decrease in growth and when CO2 was elevated there was no growth effect. Hemlock growth was increased by elevated NO2 regardless of nitrogen status and under both partial pressures of CO2; 3 and 8% increase in growth under ambient and elevated CO2, respectively. These data suggest gaseous reactive nitrogen may augment or decrease the future growth effects of elevated CO2 depending on plant species identity. In addition, perhaps because of differences in nitrogen metabolism and physiology, deciduous and evergreen tree species appear to have different responses to reactive nitrogen fumigation. These results underscore the need for examining the responses of vegetation to mixtures of gases representative of the future atmosphere rather than examining the influence of carbon dioxide alone.

  4. Highly accurate nitrogen dioxide (NO2) in nitrogen standards based on permeation.

    PubMed

    Flores, Edgar; Viallon, Joële; Moussay, Philippe; Idrees, Faraz; Wielgosz, Robert Ian

    2012-12-04

    The development and operation of a highly accurate primary gas facility for the dynamic production of mixtures of nitrogen dioxide (NO(2)) in nitrogen (N(2)) based on continuous weighing of a permeation tube and accurate impurity quantification and correction of the gas mixtures using Fourier transform infrared spectroscopy (FT-IR) is described. NO(2) gas mixtures in the range of 5 μmol mol(-1) to 15 μmol mol(-1) with a standard relative uncertainty of 0.4% can be produced with this facility. To achieve an uncertainty at this level, significant efforts were made to reduce, identify and quantify potential impurities present in the gas mixtures, such as nitric acid (HNO(3)). A complete uncertainty budget, based on the analysis of the performance of the facility, including the use of a FT-IR spectrometer and a nondispersive UV analyzer as analytical techniques, is presented in this work. The mixtures produced by this facility were validated and then selected to provide reference values for an international comparison of the Consultative Committee for Amount of Substance (CCQM), number CCQM-K74, (1) which was designed to evaluate the consistency of primary NO(2) gas standards from 17 National Metrology Institutes.

  5. Determination of nitrogen dioxide in ambient air employing diffuse reflectance Fourier transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Verma, Santosh Kumar; Deb, Manas Kanti; Verma, Devsharan

    2008-10-01

    This paper presents the development of a simple and precise analytical method for the determination of nitrogen dioxide in ambient air. In this method nitrogen dioxide is determined in the form of nitrite. The determination of nitrogen dioxide needs no reagents except for a solution of sodium hydroxide mixed with sodium arsenite (NaOH-Na 2As 2O 3) which is used as an absorbing reagent for trapping the nitrogen dioxide from the atmosphere in the form of nitrite, i.e., a prior analysis step. The determination of submicrogram levels of nitrogen dioxide is based on the selection of a strong and sharp quantitative analytical peak at 1380 cm - 1 using diffuse reflectance infrared spectroscopy (DRS-FTIR). The limit of detection (LOD) and the limit of quantification of the method are found to be 0.008 μg g - 1 NO 2- and 0.05 μg g - 1 NO 2-, respectively. The precision in terms of standard deviation and relative standard deviation value at a level of 2 μg NO 2- / 0.1 g KBr for n = 10 is found to be 0.036 μg NO 2- and 1.8%, respectively. The relative standard deviation ( n = 10) for the determination of nitrogen dioxide in ambient air was observed to be in the range 2.6-3.8%. The method proposed is time-saving and eliminates the slow and cumbersome steps of pH maintenance of the reaction mixture and color formation of the EPA recommended spectrophotometric and other methods for quantitative determination of nitrogen dioxide.

  6. Herbivore-mediated material fluxes in a northern deciduous forest under elevated carbon dioxide and ozone concentrations.

    PubMed

    Meehan, Timothy D; Couture, John J; Bennett, Alison E; Lindroth, Richard L

    2014-10-01

    Anthropogenic changes in atmospheric carbon dioxide (CO2 ) and ozone (O3 ) are known to alter tree physiology and growth, but the cascading effects on herbivore communities and herbivore-mediated nutrient cycling are poorly understood. We sampled herbivore frass, herbivore-mediated greenfall, and leaf-litter deposition in temperate forest stands under elevated CO2 (c. 560 ppm) and O3 (c. 1.5× ambient), analyzed substrate chemical composition, and compared the quality and quantity of fluxes under multiple atmospheric treatments. Leaf-chewing herbivores fluxed 6.2 g m(-2)  yr(-1) of frass and greenfall from the canopy to the forest floor, with a carbon : nitrogen (C : N) ratio 32% lower than that of leaf litter. Herbivore fluxes of dry matter, C, condensed tannins, and N increased under elevated CO2 (35, 32, 63 and 39%, respectively), while fluxes of N decreased (18%) under elevated O3 . Herbivore-mediated dry matter inputs scaled across atmospheric treatments as a constant proportion of leaf-litter inputs. Increased fluxes under elevated CO2 were consistent with increased herbivore consumption and abundance, and with increased plant growth and soil respiration, previously reported for this experimental site. Results suggest that insect herbivory will reinforce other factors, such as photosynthetic rate and fine-root production, impacting C sequestration by forests in future environments. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

  7. 75 FR 6473 - Primary National Ambient Air Quality Standards for Nitrogen Dioxide

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ...Based on its review of the air quality criteria for oxides of nitrogen and the primary national ambient air quality standard (NAAQS) for oxides of nitrogen as measured by nitrogen dioxide (NO2), EPA is making revisions to the primary NO2 NAAQS in order to provide requisite protection of public health. Specifically, EPA is establishing a new 1-hour standard at a level of......

  8. Year-round measurements of nitrogen oxides and ozone in the tropical North Atlantic marine boundary layer

    NASA Astrophysics Data System (ADS)

    Lee, J. D.; Moller, S. J.; Read, K. A.; Lewis, A. C.; Mendes, L.; Carpenter, L. J.

    2009-11-01

    A highly sensitive chemiluminescence instrument has been deployed to measure nitric oxide (NO) and nitrogen dioxide (NO2) at the Cape Verde Atmospheric Observatory in the remote tropical North Atlantic marine boundary layer (MBL). Using two different methods, the instrument was assessed to have a detection limit of around 1.8 parts per trillion by volume (pptv) for NO and 5.5 pptv for NO2 for hour-long integration periods. The overall accuracy was estimated at ˜18% for NO and 30% for NO2. Measurements of NO, NO2, and ozone (O3) over a period of 12 months in 2007 show very low levels of NOx (typically <30 pptv) and net daytime ozone destruction on most days of the measurement period. Air originating over Africa exhibited the highest levels of NOx (˜35 pptv) and reduced daily O3 destruction, with O3 production observed on a few days. Air that had not originated over Africa showed lower NOx levels (˜25 pptv), with greater observed O3 destruction. A dependence of the observed O3 destruction on NO mixing ratios, averaged over all air masses, was observed and reproduced using a simple box model. The model results imply that the presence of between 17 and 34 pptv of NO (depending on the month) would be required to turn the tropical North Atlantic from an O3 destroying to an O3 producing regime.

  9. Nitrogen dioxide and respiratory illness in children. Part IV: Effects of housing and meteorologic factors on indoor nitrogen dioxide concentrations.

    PubMed

    Spengler, J D; Schwab, M; McDermott, A; Lambert, W E; Samet, J M

    1996-12-01

    In a prospective study of infants' exposure to nitrogen dioxide (NO2)* and respiratory illness, NO2 concentrations were measured in more than 1,400 homes in Albequerque, NM, From January 1988 through June 1991 (Health Effects Institute Research Report Number 58, Parts I, II and III). This report characterizes the variability in indoor NO2 concentrations across seasons and years, and identifies factors associated with variation in concentrations between homes and across seasons. In regression analyses of winter data, NO2 levels in the infants' bedrooms were predominately determined by the presence of gas cooking ranges with continuously burning pilot lights, the presence of wall or floor furnaces, the use of the stove for space heating, and the square footage of the living space. These findings are consistent with previously published analysis of data from homes in other U.S. cities. Relatively small differences in seasonal NO2 levels were observed across years. The correlation coefficient (r) of bedroom NO2 levels obtained in the same homes was 0.66 over two winters and 0.48 over two summers. For homes that had gas cooking ranges with continuously burning pilot lights, the NO2 bedroom concentrations differed, on average, less than 5 parts per billion (ppb) across winters. These differences were hypothesized to be caused by differences in the use of indoor NO2 sources, ventilation, and ambient (outdoor) NO2 levels. We were, however, unable to demonstrate an association between year-to-year differences in seasonal indoor NO2 concentrations and reported use of cooking range, furnace, or heater, or ambient NO2 levels, or temperature.

  10. 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.

  11. A BAYESIAN METHOD OF ESTIMATING KINETIC PARAMETERS FOR THE INACTIVATION OF CRYPTOSPORIDIUM PARVUM OOCYSTS WITH CHLORINE DIOXIDE AND OZONE

    EPA Science Inventory

    The main objective of this paper is to use Bayesian methods to estimate the kinetic parameters for the inactivation kinetics of Cryptosporidium parvum oocysts with chlorine dioxide or ozone which are characterized by the delayed Chick-Watson model, i.e., a lag phase or shoulder f...

  12. Sap flux in pure aspen and mixed aspen-birch forests exposed to elevated concentrations of carbon dioxide and ozone

    Treesearch

    Johan Uddling; Ronald M. Teclaw; Mark E. Kubiske; Kurt S. Pregitzer; David S. Ellsworth

    2008-01-01

    Elevated concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]) have the potential to affect tree physiology and structure and hence forest water use, which has implications for climate feedbacks. We investigated how a 40% increase above ambient values in [CO2] and [O

  13. Effects of simulated acid rain, ozone and sulfur dioxide on suitability of elms for elm leaf beetle

    Treesearch

    Richard W. Hall; Jack H. Barger; Alden M. Townsend

    1988-01-01

    Cuttings from two clonally propagated elm hybrids ('Pioneer' and 'Homestead') were treated with ozone (03), sulfur dioxide (S02), simulated acid rain or left untreated. Fumigants were applied 7 hours per day, 5 days per week for 9 weeks in open-top chambers. Fumigation treatments were: 0.1 ppm 0

  14. A BAYESIAN METHOD OF ESTIMATING KINETIC PARAMETERS FOR THE INACTIVATION OF CRYPTOSPORIDIUM PARVUM OOCYSTS WITH CHLORINE DIOXIDE AND OZONE

    EPA Science Inventory

    The main objective of this paper is to use Bayesian methods to estimate the kinetic parameters for the inactivation kinetics of Cryptosporidium parvum oocysts with chlorine dioxide or ozone which are characterized by the delayed Chick-Watson model, i.e., a lag phase or shoulder f...

  15. Effect of nitrogen dioxide and sulfur dioxide on viability and morphology of oak pollen.

    PubMed

    Ouyang, Yuhui; Xu, Zhaojun; Fan, Erzhong; Li, Ying; Zhang, Luo

    2016-01-01

    Nitrogen dioxide (NO2) and sulfur dioxide (SO2) generated by excessive coal combustion and motor vehicle emissions are major air pollutants in the large cities of China. The objective of our study was to determine the effects of the exposure of oak pollens (Quercusmongolica) to several concentrations of NO2 or SO2. Pollen grains were exposed to 0.5 ppm to 5.0 ppm NO2 or SO2 for 4 hours and assessed for morphological damage by field emission scanning electron microscopy and for viability using the trypan blue stain. Morphological changes in pollen grains were also examined after contact with acid solutions at pH 4.0 to pH 7.0. Exposure to NO2 or SO2 significantly damaged pollen grains at all concentrations investigated, compared to exposure to air; with exposure to concentrations of 0.5 ppm to 2 ppm resulting in fissures or complete breaks in the exine and a concentration of 5 ppm resulting in complete breakdown and release of pollen cytoplasmic granules. Significantly greater amounts of pollen grain were damaged after exposure to SO2 (15.5-20.4%) than after exposure to NO2 (7.1-14.7%). Similarly, exposure to NO2 or SO2 significantly decreased the viability of pollen grains, compared with exposure to air; with SO2 being slightly more detrimental than NO2. Exposure to acid solutions also induced pollen damage, which appeared to be pH-dependent (from 24.6% at pH 6.0 to 55.8% at pH 4.0; compared to 3.8% at pH 7.0). Short-term exposure of oak pollen to high concentrations of SO2 or NO2 significantly increases their fragility and disruption, leading to subsequent release of pollen cytoplasmic granules into the atmosphere. These results suggest that heightened air pollution during the oak pollen season may possibly increase the incidence of allergic airway disease in sensitized individuals by facilitating the bioavailability of airborne pollen allergens. © 2015 ARS-AAOA, LLC.

  16. Effects of ozone and sulfur dioxide mixtures on forest vegetation of the southern Sierra Nevada. Final report

    SciTech Connect

    Taylor, O.C.; Miller, P.R.; Page, A.L.; Lund, L.J.

    1986-03-01

    In 1981 and 1982, a multidisciplinary study was conducted within a 32-mile zone from Oildale, CA eastward to points in the southern Sierra Nevada. Concentrations of sulfur in pine needles and lichens along transects tended to decrease with increasing elevation. Stable isotope ratios in soils and plant tissue ran counter to expectations because natural isotopic composition at greater distances is similiar to the source area. Recently germinated pine seedlings exposed to ozone and sulfur dioxide mixtures showed significant differences in root dry weight, suggesting that pollutant mixtures may affect seedling establishment. Surveys of the study area showed increased ozone damage to pines between 1977 and 1981. Sulfur dioxide did not appear to be acting jointly with ozone to cause existing injury.

  17. Nitrogen dioxide-induced acute lung injury in sheep.

    PubMed

    Januszkiewicz, A J; Mayorga, M A

    1994-05-20

    Lung mechanics, hemodynamics and blood chemistries were assessed in sheep (Ovis aries) before, and up to 24 h following, a 15-20 min exposure to either air (control) or approximately 500 ppm nitrogen dioxide (NO2). Histopathologic examinations of lung tissues were performed 24 h after exposure. Nose-only and lung-only routes of exposure were compared for effects on NO2 pathogenesis. Bronchoalveolar lavage fluids from air- and NO2-exposed sheep were analyzed for biochemical and cellular signs of NO2 insult. The influence of breathing pattern on NO2 dose was also assessed. Five hundred ppm NO2 exposure of intubated sheep (lung-only exposure) was marked by a statistically significant, albeit small, blood methemoglobin increase. The exposure induced an immediate tidal volume decrease, and an increase in both breathing rate and inspired minute ventilation. Pulmonary function, indexed by lung resistance and dynamic lung compliance, progressively deteriorated after exposure. Maximal lung resistance and dynamic lung compliance changes occurred at 24 h post exposure, concomitant with arterial hypoxemia. Bronchoalveolar lavage fluid epithelial cell number and total protein were significantly increased while macrophage number was significantly decreased within the 24 h post-exposure period. Histopathologic examination of lung tissue 24 h after NO2 revealed patchy edema, mild hemorrhage and polymorphonuclear and mononuclear leukocyte infiltration. The NO2 toxicologic profile was significantly attenuated when sheep were exposed to the gas through a face mask (nose-only exposure). Respiratory pattern was not significantly altered, lung mechanics changes were minimal, hypoxemia did not occur, and pathologic evidence of exudation was not apparent in nose-only, NO2-exposed sheep. The qualitative responses of this large animal species to high-level NO2 supports the concept of size dependent species sensitivity to NO2. In addition, when inspired minute ventilation was used as a dose

  18. Increasing concentrations of nitrogen dioxide pollution in rural Wales.

    PubMed

    Ashenden, T W; Edge, C P

    1995-01-01

    Monitoring of nitrogen dioxide pollution was carried out in rural environments throughout Wales during a 1-year survey to quantify any changes in background concentrations and distribution of the pollutant since an earlier survey in 1986. There were 23 sites in the present survey of which 16 had been monitored during the 1986 survey. The remaining 7 sites were based on moorland in mid-Wales within map squares for which critical loads for soil acidification are expected to be exceeded by the year 2005. All sites were chosen so as to be remote from major local sources of NO(2) and the values obtained were deemed to be minimum concentrations for the different regions. Measurements were made using diffusion tubes which aimed to provide mean concentrations of NO(2) for 2-week exposure periods. Concentrations of NO(2) were found to be higher in the winter months for most sites and this is probably related to a greater use of fossil fuels for heating buildings at this time of year. The exception was the high concentrations of NO(2) in May and June for several sites in North Wales, and in July and August for a site on Mount Snowdon. These high summer concentrations in North Wales are thought to be related to increased traffic associated with tourism. It is apparent that there has been a substantial increase in rural concentrations of NO(2) throughout Wales since the earlier survey of 1986. As an average of all 16 sites used in both surveys, there was a 53% increase in the annual mean concentration of NO(2). Also, it is evident that, since 1986, there has been a substantial increase in the area of south-eastern Wales which has a background level in excess of 10 ppb NO(2) and a notable reduction in land area with concentrations below 6 ppb NO(2) as an annual mean concentration. The possible future impact of increasing rural concentrations of NO(2) on Welsh vegetation is discussed with references to estimates of critical levels of NO(2) for adverse effects on plants.

  19. Kinetics and mechanisms of nitrate and ammonium formation during ozonation of dissolved organic nitrogen.

    PubMed

    de Vera, Glen Andrew; Gernjak, Wolfgang; Weinberg, Howard; Farré, Maria José; Keller, Jurg; von Gunten, Urs

    2017-01-01

    Dissolved organic nitrogen (DON) is an emerging concern in oxidative water treatment because it exerts oxidant demand and may form nitrogenous oxidation/disinfection by-products. In this study, we investigated the reactions of ozone with DON with a special emphasis on the formation of nitrate (NO3(-)) and ammonium (NH4(+)). In batch ozonation experiments, the formation of NO3(-) and NH4(+) was investigated for natural organic matter standards, surface water, and wastewater effluent samples. A good correlation was found between NO3(-) formation and the O3 exposure (R(2) > 0.82) during ozonation of both model DON solutions and real water samples. To determine the main precursor of NO3(-), solutions composed of tannic acid and model compounds with amine functional groups were ozonated. The NO3(-) yield during ozonation was significantly higher for glycine than for trimethylamine and dimethylamine. Experiments with glycine also showed that NO3(-) was formed via an intermediate with a second-order rate constant of 7.7 ± 0.1 M(-1)s(-1) while NH4(+) was formed by an electron-transfer mechanism with O3 as confirmed from a hydroxyl radical (OH) yield of 24.7 ± 1.9%. The NH4(+) concentrations, however, were lower than the OH yield (0.03 mol NH4(+)/mol OH) suggesting other OH-producing reactions that compete with NH4(+) formation. This study concludes that NO3(-) formation during ozonation of DON is induced by an oxygen-transfer to nitrogen forming hydroxylamine and oxime, while NH4(+) formation is induced by electron-transfer reactions involving C-centered radicals and imine intermediates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Analysing the causes of chronic cough: relation to diesel exhaust, ozone, nitrogen oxides, sulphur oxides and other environmental factors

    PubMed Central

    Groneberg-Kloft, Beatrix; Kraus, Thomas; Mark, Anke van; Wagner, Ulrich; Fischer, Axel

    2006-01-01

    Air pollution remains a leading cause of many respiratory diseases including chronic cough. Although episodes of incidental, dramatic air pollution are relatively rare, current levels of exposure of pollutants in industrialized and developing countries such as total articles, diesel exhaust particles and common cigarette smoke may be responsible for the development of chronic cough both in children and adults. The present study analyses the effects of common environmental factors as potential causes of chronic cough. Different PubMed-based researches were performed that related the term cough to various environmental factors. There is some evidence that chronic inhalation of diesel can lead to the development of cough. For long-term exposure to nitrogen dioxide (NO2), children were found to exhibit increased incidences of chronic cough and decreased lung function parameters. Although a number of studies did not show that outdoor pollution directly causes the development of asthma, they have demonstrated that high levels pollutants and their interaction with sunlight produce ozone (O3) and that repeated exposure to it can lead to chronic cough. In summary, next to the well-known air pollutants which also include particulate matter and sulphur dioxide, a number of other indoor and outdoor pollutants have been demonstrated to cause chronic cough and therefore, environmental factors have to be taken into account as potential initiators of both adult and pediatric chronic cough. PMID:16722555

  1. Effects of elevated carbon dioxide and ozone on the phytochemistry of aspen and performance of an herbivore.

    PubMed

    Kopper, Brian J; Lindroth, Richard L

    2003-01-01

    The purpose of this study was to assess the independent and interactive effects of CO(2), O(3), and plant genotype on the foliar quality of a deciduous tree and the performance of a herbivorous insect. Two trembling aspen (Populus tremuloides Michaux) genotypes differing in response to CO(2) and O(3) were grown at the Aspen FACE (Free Air CO(2) Enrichment) site located in northern Wisconsin, USA. Trees were exposed to one of four atmospheric treatments: ambient air (control), elevated carbon dioxide (+CO(2); 560 microl/l), elevated ozone (+O(3); ambient x1.5), and elevated CO(2)+O(3). We measured the effects of CO(2) and O(3) on aspen phytochemistry and on performance of forest tent caterpillar (Malacosoma disstria Hübner) larvae. CO(2) and O(3) treatments influenced foliar quality for both genotypes, with the most notable effects being that elevated CO(2) reduced nitrogen and increased tremulacin levels, whereas elevated O(3) increased early season nitrogen and reduced tremulacin levels, relative to controls. With respect to insects, the +CO(2) treatment had little or no effect on larval performance. Larval performance improved in the +O(3) treatment, but this response was negated by the addition of elevated CO(2) (i.e., +CO(2)+O(3) treatment). We conclude that tent caterpillars will have the greatest impact on aspen under current CO(2) and high O(3) levels, due to increases in insect performance and decreases in tree growth, whereas tent caterpillars will have the least impact on aspen under high CO(2) and low O(3) levels, due to moderate changes in insect performance and increases in tree growth.

  2. Determination of degradation products and pathways of mancozeb and ethylenethiourea (ETU) in solutions due to ozone and chlorine dioxide treatments.

    PubMed

    Hwang, Eun-Sun; Cash, Jerry N; Zabik, Matthew J

    2003-02-26

    The objective of the present study was to determine the degradation products of mancozeb and ethylenethiourea (ETU) and elucidate the possible degradation pathways in solution as a result of chemical oxidation using ozone and chlorine dioxide. This study was developed in a solution at 100 ppm of mancozeb and ETU concentration over the course of 60 min. Two different oxidizing agents used in this study were (1) ozone at 3 ppm and (2) chlorine dioxide at 20 ppm. Ozone was continuously provided throughout the course of the reaction. Degradation products were detected with high-resolution GC-MS. The total analysis time was 4 min per sample combined with rapid GC separation and time-of-flight mass spectrometry (TOFMS). Hydrolysis of mancozeb led to m/z 144 ion fragmentation, which is 5-imidazoledithiocarboxylic acid, as a major degradation product. ETU showed M(+) 102, which corresponds to its mass, indicating this compound was stable in distilled water and did not undergo hydrolysis during 60 min. The average retention times of mancozeb and ETU were approximately 181-189 and 210-230 s, respectively. Ozonation of mancozeb produced ETU as a major product. Treatment of ETU with ozone produced several degradation compounds. From prolonged ozonation, the CS(2) or CS group was removed. Overall, several byproducts identified were M(+) 60, M(+) 84, M(+) 163, M(+) 117, and M(+) 267 by ozone and M(+) 117, M(+) 86, and M(+) 163 by chlorine dioxide treatment. Several of these have been reported, but others have never been reported previously.

  3. Product selectivity of visible-light photocatalytic reduction of carbon dioxide using titanium dioxide doped by different nitrogen-sources

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoguo; Huang, Zhengfeng; Cheng, Xudong; Wang, Qingli; Chen, Yi; Dong, Peimei; Zhang, Xiwen

    2015-11-01

    The influence of nitrogen-source on the photocatalytic properties of nitrogen-doped titanium dioxide is herein first investigated from the perspective of the chemical bond form of the nitrogen element in the nitrogen-source. The definitive role of groups such as Nsbnd N from the nitrogen-source on the surface of as-prepared samples in the selectivity of the dominant product of photocatalytic reduction is demonstrated. Well-crystallized one-dimensional Nsbnd TiO2 nanorod arrays with a preferred orientation of the rutile (3 1 0) facet are manufactured via a hydrothermal treatment using hydrazine and ammonia variously as the source of nitrogen. Significant selectivity of the dominant reduced products has been exhibited for Nsbnd TiO2 prepared from different nitrogen-sources in carbon dioxide photocatalytic reduction under visible light illumination. CH4 is the main product with N2H4-doped Nsbnd TiO2, while CO is the main product with NH3-doped Nsbnd TiO2, which can be attributed to the existence of the reducing Nsbnd N groups in the N2H4-doped Nsbnd TiO2 surfaces after the hydrothermal treatment. Compared with the approaches previously reported, the facile one-step route utilized here accomplishes the fabrication of Nsbnd TiO2 possessing visible-light activity and attainment of selectivity of dominant photocatalytic reduction product simultaneously by choosing a nitrogen-source with appropriate chemical bond form, which provides a completely new approach to understanding the effects of doping treatment on photocatalytic properties.

  4. 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

  5. The sensitivity of OMI-derived nitrogen dioxide to boundary layer temperature inversions

    NASA Astrophysics Data System (ADS)

    Wallace, Julie; Kanaroglou, Pavlos

    We assess the sensitivity of tropospheric nitrogen dioxide (NO 2) derived from the Ozone Monitoring Instrument (OMI), to episodes of temperature inversion in the lower boundary layer. Vertical temperature data were obtained from a 91-m meteorological tower located in the study area, which is centered on the Hamilton Census Metropolitan Area, Ontario, Canada. Hamilton is an industrial city with high traffic volumes, and is therefore subjected to high levels of pollution. Pollution buildup is amplified by frequent temperature inversions which are commonly radiative, but are also induced by local physiography, proximity to Lake Ontario, and regional meteorology. The four-year period from January 2005 to December 2008 was investigated. Ground-level data for validation were obtained from in situ air quality monitors located in the study area. The results indicate that OMI is sensitive to changes in the NO 2 levels during temperature inversions, and exhibits changes which roughly parallel those of in situ monitors. Overall, an 11% increase in NO 2 was identified by OMI on inversion days, compared to a 44% increase measured by in situ monitors. The weekend effect was clearly exhibited under both normal and inversion scenarios with OMI. Seasonal and wind direction patterns also correlated fairly well with ground-level data. Temperature inversions have resulted in poor air quality episodes which have severely compromised the health of susceptible populations, sometime leading to premature death. The rationale for this study is to further assess the usefulness of OMI for population exposure studies in areas with sparse resources for ground-level monitoring.

  6. 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

  7. Destruction of cyanide waste solutions using chlorine dioxide, ozone and titania sol.

    PubMed

    Parga, J R; Shukla, S S; Carrillo-Pedroza, F R

    2003-01-01

    Increasingly, there are severe environmental controls in the mining industry. Because of lack of technological advances, waste management practices are severely limited. Most of the wastes in the milling industrial effluents are known to contain cyanides and it is recognized that after extraction and recovery of precious metals, substantial amounts of cyanide are delivered to tailings ponds. The toxicity of cyanide creates serious environmental problems. In this paper we describe several methods for the treatment of cyanide solutions. These include: (1) cyanide destruction by oxidation with chlorine dioxide (ClO(2)) in a Gas-Sparged Hydrocyclone (GSH) reactor; (2) destruction of cyanide by ozone (O(3)) using a stirred batch reactor, and finally, (3) the photolysis of cyanide with UV light in presence of titania sol. In all cases excellent performance were observed as measured by the extent and of the destruction.

  8. Destruction of cyanide waste solutions using chlorine dioxide, ozone and titania sol

    SciTech Connect

    Parga, J.R.; Shukla, S.S.; Carrillo-Pedroza, F.R

    2003-07-01

    Increasingly, there are severe environmental controls in the mining industry. Because of lack of technological advances, waste management practices are severely limited. Most of the wastes in the milling industrial effluents are known to contain cyanides and it is recognized that after extraction and recovery of precious metals, substantial amounts of cyanide are delivered to tailings ponds. The toxicity of cyanide creates serious environmental problems. In this paper we describe several methods for the treatment of cyanide solutions. These include: (1) cyanide destruction by oxidation with chlorine dioxide (ClO{sub 2}) in a Gas-Sparged Hydrocyclone (GSH) reactor; (2) destruction of cyanide by ozone (O{sub 3}) using a stirred batch reactor, and finally, (3) the photolysis of cyanide with UV light in presence of titania sol. In all cases excellent performance were observed as measured by the extent and of the destruction.

  9. The importance of ozone in the oxidation of sulfur dioxide in nonurban tropospheric clouds

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1982-01-01

    In studies of the various possible mechanisms which contribute to the conversion of atmospheric sulfur dioxide to sulfate aerosol in the atmosphere, oxidation within the aqueous, droplet phase of tropospheric clouds has been identified as a major contributor. It has appeared that possibly much of this oxidation is by hydrogen peroxide, with the contribution from ozone being only minimal. The present investigation is concerned with the relative importance of O3 and H2O2 oxidation as a function of pH. The results of a new experimental study of the O3-S(IV) reaction in aqueous solution are presented, and potential S(IV) oxidation rates by O3 in cloud water are compared with those predicted for H2O2. The investigation indicates the potential importance of O3 as a contributor to the overall oxidative conversion of SO2 within typical nonpolluted tropospheric clouds.

  10. Summary of aircraft results for 1978 southeastern Virginia urban plume measurement study of ozone, nitrogen oxides, and methane

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Wornom, D. E.; Mathis, J. J., Jr.; Sebacher, D. I.

    1980-01-01

    Ozone production was determined from aircraft and surface in situ measurements, as well as from an airborne laser absorption spectrometer. Three aircraft and approximately 10 surface stations provided air-quality data. Extensive meteorological, mixing-layer-height, and ozone-precursor data were also measured. Approximately 50 hrs (9 flight days) of data from the aircraft equipped to monitor ozone, nitrogen oxides, dewpoint temperature, and temperature are presented. In addition, each experiment conducted is discussed.

  11. Measurement and modeling of ozone and nitrogen oxides produced by laser breakdown in oxygen-nitrogen atmospheres.

    PubMed

    Gornushkin, Igor B; Stevenson, Chris L; Galbács, Gábor; Smith, Ben W; Winefordner, James D

    2003-11-01

    The production of ozone nad nitrogen oxides was studied during multiple laser breakdown in oxygen-nitrogen mixtures at atmospheric pressure. About 2000 laser shots at 10(10) W cm-2 were delivered into a sealed reaction chamber. The chamber with a long capillary was designed to measure absorption of O3, NO, and NO2 as a function of the number of laser shots. The light source for absorption measurements was the continuum radiation emitted by the plasma during the first 0.2 microsecond of its evolution. A kinetic model was developed that encompassed the principal chemical reactions between the major atmospheric components and the products of laser breakdown. In the model, the laser plasma was treated as a source of nitric oxide and atomic oxygen, whose rates of production were calculated using measured absorption by NO, NO2, and O3. The calculated concentration profiles for NO, NO2, and O3 were in good agreement with measured profiles over a time scale of 0-200 s. The steady-state concentration of ozone was measured in a flow cell in air. For a single breakdown in air, the estimated steady-state yield of ozone was 2 x 10(12) molecules, which agreed with the model prediction. This study can be of importance for general understanding of laser plasma chemistry and for elucidating the nature of spectral interferences and matrix effects that may take place in applied spectrochemical analysis.

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

    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. )

    1993-06-01

    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.

  13. Isotopic fractionation in the formation of ozone and of carbon dioxide

    SciTech Connect

    Bates, D.R.

    1990-12-15

    An explanation is proposed for the observed enrichment of the symmetric isomer OXO of heavy ozone (X being used to denote a heavy O atom). This that the energized complex may undergo a flip in which one of the end atoms ceases to be effectively bound to the central atom and becomes effectively bound to the other end atom. The measured OXO:OOX ratio is reproduced if the flip frequency is the same as the dissociation frequency. Calculations are carried out on the variation of the enhancement with the ambient gas density. It is reasoned that the enhancement observed in the stratosphere is that arising in termolecular association and that the lower values obtained in laboratory experiments are artifacts. The measured isotopic enrichment of carbon dioxide may arise form termolecular association O + CO + CO {yields} CO2 + CO, from enriched OXO that is generated in another association process or from both. The apparent scatter in the results is much greater than would be expected from the precision of the measurements. It is suggested that this may be an artifact (similar in origin to those for ozone).

  14. Tropospheric ozone differential-absorption lidar using stimulated Raman scattering in carbon dioxide.

    PubMed

    Nakazato, Masahisa; Nagai, Tomohiro; Sakai, Tetsu; Hirose, Yasuo

    2007-04-20

    A UV ozone differential-absorption lidar (DIAL) utilizing a Nd:YAG laser and a single Raman cell filled with carbon dioxide (CO(2)) is designed, developed, and evaluated. The generated wavelengths are 276, 287, and 299 nm, comprising the first to third Stokes lines of the stimulated Raman scattering technique. The correction terms originated from the aerosol extinction, the backscatter, and the absorption by other gases are estimated using a model atmosphere. The experimental results demonstrate that the emitted output energies were 13 mJ/pulse at 276 nm and 287 nm and 5 mJ/pulse at 299 nm, with pump energy of 91 mJ/pulse and a CO(2) pressure of 0.7 MPa. The three Stokes lines account for 44.0% of the available energy. The use of argon or helium as a buffer gas in the Raman cell was also investigated, but this leads to a dramatic decrease in the third Stokes line, which makes this wavelength practically unusable. Our observations confirmed that 30 min of integration were sufficient to observe ozone concentration profiles up to 10 km. Aerosol extinction and backscatter correction are estimated and applied. The aerosol backscatter correction profile using 287 and 299 nm as reference wavelengths is compared with that using 355 nm. The estimated statistical error is less than 5% at 1.5 km and 10% at 2.6 km. Comparisons with the operational carbon-iodine type chemical ozonesondes demonstrate 20% overestimation of the ozone profiles by the DIAL technique.

  15. Transfer of oxygen, nitrogen, and carbon dioxide through normal adult human skin.

    PubMed

    Hansen, T N; Sonoda, Y; McIlroy, M B

    1980-09-01

    The resistance to the flow of oxygen, nitrogen, and carbon dioxide through the skin ws measured in three normal adult human subjects. A sampling chamber 2.5 cm in diameter, heated to 43-44 degrees C, was applied to the skin of the forearm and gas sampled with a mass spectrometer at a rate of about 10(-5) ml . s-1 through membranes of different resistance. Skin resistance was calculated from the results of sequential studies with different membranes of known resistance on the sampling chamber. The resistance to oxygen flow (1.79 +/- 0.92 X 10(3) atm . ml-1 . min . cm2) was 1/5 of that for nitrogen and 28.5 times that for carbon dioxide. The response time of the skin to a sudden change in arterial gas tension was investigated by having the subjects rebreathe 5% carbon dioxide in oxygen and then breathe air. The mean transit times though the skin for oxygen and carbon dioxide were similar (approx 30 s) and about twice those for nitrogen. The finding of similar response times for oxygen and carbon dioxide transfer in the face of large differences in resistance suggests that there is a high capacitance for carbon dioxide in the skin, presumably due to its high solubility and the effects of buffering.

  16. Induction of SOS functions in Escherichia coli and biosynthesis of nitrosamine in rabbits by nitrogen dioxide

    SciTech Connect

    Kosaka, H.; Uozumi, M.; Nakajima, T.

    1987-08-01

    Nitrogen dioxide induced SOS functions in Salmonella typhimurium and Escherichia coli K-12 and was mutagenic in Escherichia coli WP2. When a rabbit was administered aminopyrine intravenously and administered nitrogen dioxide by inhalation, N-nitrosodimethylamine was detected in its blood. Analysis was conducted with /sup 15/N-nitrosodimethylamine as an internal standard by a combination of capillary gas chromatography and mass spectrometry. Accompanying administration of cystamine increased the blood concentration of N-nitrosodimethylamine in the rabbit, suggesting inhibition of its metabolism. Concurrent sulfur trioxide inhalation increased N-nitrosodimethylamine formation in the rabbit.

  17. Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate.

    PubMed

    Ramseier, Maaike K; Peter, Andreas; Traber, Jacqueline; von Gunten, Urs

    2011-02-01

    Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed significant amounts of AOC, i.e. more than 100 μg/L AOC were formed with 4.6 mg/L ozone and ferrate in water with 3.8 mg/L dissolved organic carbon. In the same water samples chlorine dioxide, chlorine, and permanganate produced no or only limited AOC. When cyanobacterial cells (Aphanizomenon gracile) were added to the water, an AOC increase was detected with ozone, permanganate, and ferrate, probably due to cell lysis. This was confirmed by the increase of extracellular geosmin, a substance found in the selected cyanobacterial cells. AOC formation by chlorine and chlorine dioxide was not affected by the presence of the cells. The formation of oxalate upon oxidation was found to be a linear function of the oxidant consumption for all five oxidants. The following molar yields were measured in three different water matrices based on oxidant consumed: 2.4-4.4% for ozone, 1.0-2.8% for chlorine dioxide and chlorine, 1.1-1.2% for ferrate, and 11-16% for permanganate. Furthermore, oxalate was formed in similar concentrations as trihalomethanes during chlorination (yield ∼ 1% based on chlorine consumed). Oxalate formation kinetics and stoichiometry did not correspond to the AOC formation. Therefore, oxalate cannot be used as a surrogate for AOC formation during oxidative water treatment.

  18. Dissolved organic nitrogen and its biodegradable portion in a water treatment plant with ozone oxidation.

    PubMed

    Wadhawan, Tanush; Simsek, Halis; Kasi, Murthy; Knutson, Kristofer; Prüβ, Birgit; McEvoy, John; Khan, Eakalak

    2014-05-01

    Biodegradability of dissolved organic nitrogen (DON) has been studied in wastewater, freshwater and marine water but not in drinking water. Presence of biodegradable DON (BDON) in water prior to and after chlorination may promote formation of nitrogenous disinfectant by-products and growth of microorganisms in the distribution system. In this study, an existing bioassay to determine BDON in wastewater was adapted and optimized, and its application was tested on samples from four treatment stages of a water treatment plant including ozonation and biologically active filtration. The optimized bioassay was able to detect BDON in 50 μg L(-1) as N of glycine and glutamic solutions. BDON in raw (144-275 μg L(-1) as N), softened (59-226 μg L(-1) as N), ozonated (190-254 μg L(-1) as N), and biologically filtered (17-103 μg L(-1) as N) water samples varied over a sampling period of 2 years. The plant on average removed 30% of DON and 68% of BDON. Ozonation played a major role in increasing the amount of BDON (31%) and biologically active filtration removed 71% of BDON in ozonated water.

  19. 40 CFR Appendix F to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) F Appendix...—Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere...

  20. 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

    ... Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) F Appendix...—Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas... concentration standard. NO2 concentration standard. 2.1 Principle. Atmospheres containing accurately...

  1. 40 CFR Appendix F to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase Chemiluminescence) F Appendix...—Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas... concentration standard. NO2 concentration standard. 2.1 Principle. Atmospheres containing accurately...

  2. Visible injury and nitrogen metabolism of rice leaves under ozone stress, and effect on sugar and protein contents in grain

    NASA Astrophysics Data System (ADS)

    Huang, Y. Z.; Sui, L. H.; Wang, W.; Geng, C. M.; Yin, B. H.

    2012-12-01

    Effect of ozone on the visible injury, nitrogen metabolism of rice leaves, and sugar and protein contents in rice grain was carried out by the open-top chamber. The results indicated that ozone stress caused obvious injury in rice leaves. The increase in ozone concentration had significant influence on the nitrate reductase activity in rice leaves. At the ozone concentration of 40, 80 and 120 nL L-1, the nitrate reductase activities in rice leaves in the tillering stage, the jointing stage, the heading stage and milk stage were separately reduced by 25.3-86.3%, 57.4-97.8%, 91.0-99.3% and 89.5-96.7% compared with those in the control treatment. As ozone concentration increased, the contents of ammonium nitrogen and nitrate nitrogen in rice leaves were obviously reduced. Ozone stress also had an influence on the contents of sugar and protein in rice grain. The stress of high ozone concentration (120 nL L-1) caused the starch content in grain to reduce by 15.8% than that in the control treatment, but total soluble sugars in grain was actually enhanced by 47.5% compared to that in the control treatment. The contents of albumin and glutenin in rice grain increased with increasing the ozone concentration, and prolamin and crude protein contents in rice grain increased only at the higher ozone concentration. Under ozone concentration of 120 nL L-1, the contents of albumin, glutenin and crude protein in rice grain were increased respectively by 23.1%, 21.0% and 21.1% compared with those in the control treatment. The result suggested that ozone tress has an influence on nitrogen metabolism of rice leaves and grain quality.

  3. Staggering reductions in atmospheric nitrogen dioxide across Canada in response to legislated transportation emissions reductions

    NASA Astrophysics Data System (ADS)

    Reid, Holly; Aherne, Julian

    2016-12-01

    It is well established that atmospheric nitrogen dioxide (NO2), associated mainly with emissions from transportation and industry, can have adverse effects on both human and ecosystem health. Specifically, atmospheric NO2 plays a role in the formation of ozone, and in acidic and nutrient deposition. As such, international agreements and national legislation, such as the On-Road Vehicle and Engine Emission Regulations (SOR/2003-2), and the Federal Agenda on Cleaner Vehicles, Engines and Fuel have been put into place to regulate and limit oxidized nitrogen emissions. The objective of this study was to assess the response of ambient air concentrations of NO2 across Canada to emissions regulations. Current NO2 levels across Canada were examined at 137 monitoring sites, and long-term annual and quarterly trends were evaluated for 63 continuous monitoring stations that had at least 10 years of data during the period 1988-2013. A non-parametric Mann-Kendall test (Z values) and Sen's slope estimate were used to determine monotonic trends; further changepoint analysis was used to determine periods with significant changes in NO2 air concentration and emissions time-series data. Current annual average NO2 levels in Canada range between 1.16 and 14.96 ppb, with the national average being 8.43 ppb. Provincially, average NO2 ranges between 3.77 and 9.25 ppb, with Ontario and British Columbia having the highest ambient levels of NO2. Long-term tend analysis indicated that the annual average NO2 air concentration decreased significantly at 87% of the stations (55 of 63), and decreased non-significantly at 10% (5 of 63) during the period 1998-2013. Concentrations increased (non-significantly) at only 3% (2 of 63) of the sites. Quarterly long-term trends showed similar results; significant decreases occurred at 84% (January-March), 88% (April-June), 83% (July-September), and 81% (October-December) of the sites. Declines in transportation emissions had the most influence on NO2 air

  4. Yield of Ozone, Nitrite Nitrogen and Hydrogen Peroxide Versus Discharge Parameter Using APPJ Under Water

    NASA Astrophysics Data System (ADS)

    Chen, Bingyan; Zhu, Changping; Fei, Juntao; He, Xiang; Yin, Cheng; Wang, Yuan; Gao, Ying; Jiang, Yongfeng; Wen, Wen; Chen, Longwei

    2016-03-01

    Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given. supported by National Natural Science Foundation of China (Nos. 11274092, 11404092, 61401146), the Nantong Science and Technology Project, Nantong, China (No. BK2014024), the Open Project of Jiangsu Province Key Laboratory of Environmental Engineering, Nanjing, China (No. KF2014001), and the Fundamental Research Funds for the Central Universities of China (No. 2014B11414)

  5. Nickel(II) Dithiocarbamate Complexes Containing Sulforhodamine B as Fluorescent Probes for Selective Detection of Nitrogen Dioxide

    PubMed Central

    Yan, Yan; Krishnakumar, Saarangan; Yu, Huan; Ramishetti, Srinivas; Deng, Lih Wen; Wang, Suhua; Huang, Leaf; Huang, Dejian

    2013-01-01

    We synthesized the Ni(II) complexes with dithiocarbamate ligand derived from ortho and para isomers sulforhodamine B fluorophores and demonstrated they are highly selective in reaction with nitrogen dioxide (NO2). Comparing to the para isomer, the ortho isomer showed much greater fluorescence increase upon reaction with nitrogen dioxide, which led to oxidation and de-complexation of dithiocarbamate ligand from Ni(II). We applied this probe for visual detection of 1 ppm nitrogen dioxide in gas phase and fluorescence imaging of NO2 in macrophage cells treated with nitrogen oxide donor. PMID:23530626

  6. Long-term trends of Nitrogen oxides and surface ozone concentrations in Tehran city, 2002-2011.

    PubMed

    Motesaddi Zarandi, Saeed; Alimohammadi, Mahmood; Kazemi Moghaddam, Vahid; Hasanvand, Mohammad Sadegh; Miranzadeh, Mohammad Bagher; Rabbani, Davarkhah; Mostafaii, Gholam Reza; Sarsangi, Vali; Hajiketabi, Sajjad; Mazaheri Tehrani, Ashraf

    2015-01-01

    Tropospheric ozone is a problem with multi aspects - hazard to human health, plant, and welfare and a key factor to climate change, air pollution and atmosphere chemistry, as well. Behavior of ozone and nitrogen oxides (NO, and NO2) concentration is highly complex and variable; therefore, their trends as short and long-term were significantly attended. Most of the studies were carried out on the behavior of pollutant concentrations in North America, Europe, and East Asia, but few studies have been conducted in west Asia. The aim of this study was to assess daily changes and long-term trend of ozone and nitrogen oxides concentrations in Tehran city, Iran from March 2002 to September 2011. Data were collected from 18 air quality monitoring stations. The data were sorted as daily mean of 10 years (daily changes) and annual mean for each year (long-term trend). One-sample test was used to assess the statistical significance. Current findings indicated that changes of ozone, NO, and NO2 concentrations are dependent from job shifts and photochemical reactions. Annual mean concentrations of ozone and NO2 were gradually increased, long-term trend of ozone and NO2 concentration indicated. The correlation between long term trend of ozone and NO2 was significant (p < 0.05). The controlling program was the most important factor in long-term concentration of ozone, and nitrogen oxides, but some problems and difficulties were accounted to perform controlling program.

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. Recharge processes of paramagnetic centers during illumination in nitrogen-doped nanocrystalline titanium dioxide

    NASA Astrophysics Data System (ADS)

    Le, N. T.; Konstantinova, E. A.; Kokorin, A. I.; Kodom, T.; Alonso-Vante, N.

    2015-08-01

    Nitrogen-doped titanium dioxide (N-TiO2) has been investigated by the EPR-technique. Two types of paramagnetic centers - N• and NO•-radicals - were detected in the samples. Both N• and NO•-related centers are recharged during illumination. Band diagrams of TiO2 with N• and NO• radicals energy level position are proposed.

  14. Temporary Disturbance of Translocation of Assimilates in Douglas Firs Caused by Low Levels of Ozone and Sulfur Dioxide 1

    PubMed Central

    Gorissen, Antonie; van Veen, Johannes A.

    1988-01-01

    Douglas firs (Pseudotsuga menziesii [Mirb.] Franco) are suffering strongly from air pollution in western Europe. We studied the effect of low concentrations of ozone (200 micrograms per cubic meter during 3 days) and sulfur dioxide (53 micrograms per cubic meter during 28 days) on translocation of assimilates in 2 year old Douglas firs. The trees were exposed to the pollutants and afterward transferred to a growth chamber adapted to the use of 14CO2. Root/soil respiration was measured daily. The results showed a significant decrease of the 14CO2 root/soil respiration during the first 1 to 2 weeks after exposure to either ozone or sulfur dioxide. The ultimate level of 14CO2 root/soil respiration did not differ significantly, which suggests a recovery of the exposed trees during the first weeks after exposure. PMID:16666348

  15. Sources of Variability in the Stratospheric Column of Nitrogen Dioxide

    NASA Technical Reports Server (NTRS)

    Douglass, Anne; Gleason, James; Chin, Mian; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Instruments such as the Global Ozone Monitoring Experiment (GOME, on the European Remote Sensing Satellite (ERS-2), launched 1995), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY, on ENVISAT, to be launched July 2001) and the Ozone Monitoring Instrument (OMI on EOS Aura, to be launched 2003) make measurements of the total column of NO2. There is interest in separating the stratospheric and tropospheric contributions to the column, as the tropospheric column provides a measure of pollution. We are using a 3D chemistry and transport model driven by winds from the Goddard Space Flight Center Data Assimilation System to examine variability in the stratospheric NO2 column. Model results for NOx = NO + NO2 + 2N2O5 will be shown to compare well with sunset observations from the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite, and to exhibit similar temporal and spatial dependence. Partitioning between NO, NO2, and N2O5 is also shown to compare well with observations. This good agreement supports the use of simulated fields in the stratosphere to derive the tropospheric column from the total column. Preliminary comparisons of the tropospheric column with model simulations for the troposphere will also be shown.

  16. Efficacy of Nucleic Acid Probes for Detection of Poliovirus in Water Disinfected by Chlorine, Chlorine Dioxide, Ozone, and UV Radiation

    PubMed Central

    Moore, Norman J.; Margolin, Aaron B.

    1994-01-01

    MilliQ water was inoculated with poliovirus type 1 strain LSc-1 and was treated with disinfectants, including chlorine, chlorine dioxide, ozone, and UV light. No relationship between probes and plaque assays were seen, demonstrating that viral nucleic acids were not destroyed. These findings suggest that nucleic acid probes cannot distinguish between infectious and noninfectious viruses and cannot be used in the evaluation of treated waters. PMID:16349448

  17. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  18. Effects of ozone and sulfur dioxide on tuber yield and quality of potatoes

    SciTech Connect

    Foster, K.W.; Timm, H.; Labanauskas, C.K.; Oshima, R.J.

    1983-01-01

    Air pollution injury of the potato plant (Solanum tuberosum L.) has been documented previously, but potato yield losses have not been estimated in replicated experiments having controlled exposures to ozone (O/sub 3/) and sulfur dioxide (SO/sub 2/). A controlled-environment study involving the speckle-leaf-sensitive cultivar 'Centennial Russet' was conducted to examine the effects of chronic exposure to O/sub 3/ and SO/sub 2/ on plant growth and tuber yield and quality. Ozone, at the highest seasonal dose (44.2 ppm-h), reduced leaf dry weight 48%, root dry weight 58%, tuber number 38%, and total tuber yield 45%. Lower exposures affected these parameters in linear proportion to the O/sub 3/ dose. Mean stem (minus leaves) dry weight, tuber dry weight, tuber dry matter percentage, partitioning of dry matter to tubers, and tuber sugar concentrations were not affected. Tuber N concentration increased linearly by up to 21% as the O/sub 3/ dose increased. Plants grown outside of chambers in ambient air showed effects consistent with results obtained within the chambers. The plants grown outside received a total seasonal O/sub 3/ dose of 50.4 ppm-h and produced 58% less tuber yield than filtered air control plants.Plant responses to SO/sub 2/ exposure were much less pronounced than their responses to exposure to O/sub 3/. However, leaf symptom development in O/sub 3/-treated plants was markedly intensified by the presence of SO/sub 2/. Small reductions in tuber yield and mean tuber size, but not in tuber number, were observed in SO/sub 2/-treated plants. Tuber N concentration increased slightly in SO/sub 2/-treated plants. A significant O/sub 3/ X SO/sub 2/ interaction was observed in the case of tuber N concentration only; SO/sub 2/ accentuated the O/sub 3/-induced increase in N content.

  19. Effects of ozone and sulfur dioxide on phyllosphere fungi from three tree species.

    PubMed

    Fenn, M E; Dunn, P H; Durall, D M

    1989-02-01

    Short-term effects of ozone (O(3)) on phyllosphere fungi were studied by examining fungal populations from leaves of giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) and California black oak (Quercus kelloggii Newb.). Chronic effects of both O(3) and sulfur dioxide (SO(2)) were studied by isolating fungi from leaves of mature Valencia orange (Citrus sinensis L.) trees. In this chronic-exposure experiment, mature orange trees were fumigated in open-top chambers at the University of California, Riverside, for 4 years with filtered air, ambient air plus filtered air (1:1), ambient air, or filtered air plus SO(2) at 9.3 parts per hundred million. Populations of Alternaria alternata (Fr.) Keissler and Cladosporium cladosporioides (Fres.) de Vries, two of the four most common fungi isolated from orange leaves, were significantly reduced by chronic exposure to ambient air. In the short-term experiments, seedlings of giant sequoia or California black oak were fumigated in open-top chambers in Sequoia National Park for 9 to 11 weeks with filtered air, ambient air, or ambient air plus O(3). These short-term fumigations did not significantly affect the numbers of phyllosphere fungi. Exposure of Valencia orange trees to SO(2) at 9.3 parts per hundred million for 4 years reduced the number of phyllosphere fungi isolated by 75% compared with the number from the filtered-air treatment and reduced the Simpson diversity index value from 3.3 to 2.5. A significant chamber effect was evident since leaves of giant sequoia and California black oak located outside of chambers had more phyllosphere fungi than did seedlings within chambers. Results suggest that chronic exposure to ambient ozone or SO(2) in polluted areas can affect phyllosphere fungal communities, while short-term exposures may not significantly disturb phyllosphere fungi.

  20. Effects of Ozone and Sulfur Dioxide on Phyllosphere Fungi from Three Tree Species

    PubMed Central

    Fenn, Mark E.; Dunn, Paul H.; Durall, Daniel M.

    1989-01-01

    Short-term effects of ozone (O3) on phyllosphere fungi were studied by examining fungal populations from leaves of giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) and California black oak (Quercus kelloggii Newb.). Chronic effects of both O3 and sulfur dioxide (SO2) were studied by isolating fungi from leaves of mature Valencia orange (Citrus sinensis L.) trees. In this chronic-exposure experiment, mature orange trees were fumigated in open-top chambers at the University of California, Riverside, for 4 years with filtered air, ambient air plus filtered air (1:1), ambient air, or filtered air plus SO2 at 9.3 parts per hundred million. Populations of Alternaria alternata (Fr.) Keissler and Cladosporium cladosporioides (Fres.) de Vries, two of the four most common fungi isolated from orange leaves, were significantly reduced by chronic exposure to ambient air. In the short-term experiments, seedlings of giant sequoia or California black oak were fumigated in open-top chambers in Sequoia National Park for 9 to 11 weeks with filtered air, ambient air, or ambient air plus O3. These short-term fumigations did not significantly affect the numbers of phyllosphere fungi. Exposure of Valencia orange trees to SO2 at 9.3 parts per hundred million for 4 years reduced the number of phyllosphere fungi isolated by 75% compared with the number from the filtered-air treatment and reduced the Simpson diversity index value from 3.3 to 2.5. A significant chamber effect was evident since leaves of giant sequoia and California black oak located outside of chambers had more phyllosphere fungi than did seedlings within chambers. Results suggest that chronic exposure to ambient ozone or SO2 in polluted areas can affect phyllosphere fungal communities, while short-term exposures may not significantly disturb phyllosphere fungi. PMID:16347849

  1. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  2. Nitrogen soil emissions and belowground plant processes in Mediterranean annual pastures are altered by ozone exposure and N-inputs

    NASA Astrophysics Data System (ADS)

    Sánchez-Martín, L.; Bermejo-Bermejo, V.; García-Torres, L.; Alonso, R.; de la Cruz, A.; Calvete-Sogo, H.; Vallejo, A.

    2017-09-01

    Increasing tropospheric ozone (O3) and atmospheric nitrogen (N) deposition alter the structure and composition of pastures. These changes could affect N and C compounds in the soil that in turn can influence soil microbial activity and processes involved in the emission of N oxides, methane (CH4) and carbon dioxide (CO2), but these effects have been scarcely studied. Through an open top chamber (OTC) field experiment, the combined effects of both pollutants on soil gas emissions from an annual experimental Mediterranean community were assessed. Four O3 treatments and three different N input levels were considered. Fluxes of nitric (NO) and nitrous (N2O) oxide, CH4 and CO2 were analysed as well as soil mineral N and dissolved organic carbon. Belowground plant parameters like root biomass and root C and N content were also sampled. Ozone strongly increased soil N2O emissions, doubling the cumulative emission through the growing cycle in the highest O3 treatment, while N-inputs enhanced more slightly NO; CH4 and CO2 where not affected. Both N-gases had a clear seasonality, peaking at the start and at the end of the season when pasture physiological activity is minimal; thus, higher microorganism activity occurred when pasture had a low nutrient demand. The O3-induced peak of N2O under low N availability at the end of the growing season was counterbalanced by the high N inputs. These effects were related to the O3 x N significant interaction found for the root-N content in the grass and the enhanced senescence of the community. Results indicate the importance of the belowground processes, where competition between plants and microorganisms for the available soil N is a key factor, for understanding the ecosystem responses to O3 and N.

  3. 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.

  4. 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.

  5. 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.

  6. Spatiotemporal patterns of correlation between atmospheric nitrogen dioxide and aerosols over South Asia

    NASA Astrophysics Data System (ADS)

    ul-Haq, Zia; Tariq, Salman; Ali, Muhammad

    2016-10-01

    An accurate knowledge is needed on the complex relation between atmospheric trace gasses and aerosol variability and their sources to explain trace gases-aerosols-climate interaction and next-generation modeling of climate change and air quality. In this regard, we have used tropospheric Nitrogen Dioxide (NO2), Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) obtained from satellite-based Ozone Monitoring Instrument (OMI)/Aura and Moderate-Resolution Imaging Spectroradiometer (MODIS)/Aqua over South Asia. NO2-AOD correlation with coefficient r = 0.49 is determined over the landmass of South Asia during 2005-2015. Yearly mean NO2-AOD correlation over South Asia shows large variations ranging from r = 0.32 to 0.86 in 2008 and 2009, respectively. The highest correlation (r = 0.66) is seen over eastern regions of Bangladesh and India, as well as adjoining areas of western Myanmar mostly linked to anthropogenic activities. A significant correlation (r = 0.59) associated with natural causes is found over some parts of Sistan region, located at the borders of Iran, Pakistan and Afghanistan, and adjoining territory. We find significant positive correlations for monsoon and post-monsoon seasons with r = 0.50 and r = 0.61, respectively. A linear regression on the annual correlation coefficients data suggests that NO2-AOD correlation is strengthening with an increase of 12.9% over South Asia during the study period. The spatial distribution of data slopes reveals positive trends in NO2-AOD correlation over megacities Lahore, Dhaka, Mumbai and Kolkata linked to growing anthropogenic activities. Singrauli city (India) has the highest correlation (r = 0.62) and 35% increase in correlation coefficient value per year. A negative correlation is observed for megacity Karachi (r = -0.37) suggesting the non-commonality of NO2 and aerosols emission sources. AE has also been used to discuss its correlation with NO2 over the areas with dominance of fine-mode aerosols.

  7. Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge.

    PubMed

    Hong, Seongkyeol; Jang, Jaesung

    2016-11-06

    Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p > 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.

  8. Reactive nitrogen, ozone, and nitrate aerosols observed in the Arctic stratosphere in January 1990

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Aimedieu, P.; Koike, M.; Iwasaka, Y.; Newman, P. A.; Schmidt, U.; Matthews, W. A.; Hayashi, M.; Sheldon, W. R.

    1992-01-01

    Ozone mixing ratios in the vicinity of the 525-K potential temperature surface in January and early February of 1990 were observed to decrease sharply across the edge of the vortex boundary, where the vortex position was estimated from Ertel's potential vorticity. The changes in NO(y) mixing ratio with respect to altitude measured on January 18 and 31 were quite well correlated with those of ozone between 15 and 24 km, indicating that NO(y) also had a large gradient across the edge of the vortex. This is interpreted as being mainly due to the significant denitrification that occurred inside the vortex. The total amount of gas and particulate phase HNO3 was close to the NO(y) amount at the altitude of the 22- to 23-km region, suggesting that the conversion of non-HNO3 reactive nitrogen to HNO3 had occurred with a PSC.

  9. Joint effects of elevated levels of ultraviolet-B radiation, carbon dioxide and ozone on plants.

    PubMed

    Krupa, Sagar V

    2003-12-01

    There is growing interest regarding the joint effects of elevated levels of surface ultraviolet B (UV-B) radiation, carbon dioxide (CO2) and ozone (O3) on plants. Our current knowledge of this subject is too limited to draw any specific conclusions, although one might state that such effects are likely to be highly species dependent and may be more than additive, additive or less than additive. There are a number of uncertainties associated with the experimental protocols used and the conclusions reached in many studies. Nevertheless, in North America, there appear to be genotypes of three monocot crop species (Avena sativa L., Oryza sativa L. and Sorghum vulgare L.); six dicot crops (Cucumis sativus L., Lactuca sativa L., Lycopersicon esculentum Mill., Phaseolus vulgaris L., Pisum sativum L. and Solanum tuberosum L.) and two conifer species (Pinus ponderosa Dougl. and Pinus taeda L.) that may be considered sensitive to the joint effects of elevated levels of UV-B, CO2 and O3. However, to provide a more reliable assessment or validation of the predictions, future research must consider the concept of plant response surfaces and describe them more fully in numerical terms. Achieving that objective will require close cooperation among a number of scientists representing geographic locations with known spatial and temporal differences in UV-B, CO2 and O3 to conduct experiments under their site-specific conditions, using common plant materials and experimental protocols.

  10. Pilot study on bromate reduction in ozonation of water with low carbonate alkalinities by carbon dioxide.

    PubMed

    Li, Ji; Zou, Li; Guo, Lulu; Ji, Jialin

    2011-01-01

    A pilot study was carried out to explore the application of carbon dioxide for pH depression in a bubble column and its ability to inhibit bromate formation for water with a low alkalinity. Results showed that in the absence of ammonia, CO2 was capable of reducing bromate 38.0%-65.4% with one-unit pH depression. CO2 caused a slightly lower bromate reduction (4.2%) than did H2SO4 when the pH was depressed to 7.4, and a more a pronounced lower reduction (8.8%) when the pH was depressed to 6.9. In the presence of 0.20 mg/L-N ammonia, bromate was largely inhibited with 73.9% reduction. When the pH was depressed to 7.4, CO2 and H2SO4 showed an 11.3% and 23.5% bromate reduction respectively, demonstrating that the joint use of CO2 and ammonia might be a plausible strategy of blocking all three bromate formation pathways. CO2 could be applied through the aeration diffuser together with ozone gas, resulting in a similar bromate reduction compared with the premixing method through Venturi mixer.

  11. Aqueous phase oxidation of sulphur dioxide by ozone in cloud droplets

    NASA Astrophysics Data System (ADS)

    Hoyle, C. R.; Fuchs, C.; Järvinen, E.; Saathoff, H.; Dias, A.; El Haddad, I.; Gysel, M.; Coburn, S. C.; Tröstl, J.; Bernhammer, A.-K.; Bianchi, F.; Breitenlechner, M.; Corbin, J. C.; Craven, J.; Donahue, N. M.; Duplissy, J.; Ehrhart, S.; Frege, C.; Gordon, H.; Höppel, N.; Heinritzi, M.; Kristensen, T. B.; Molteni, U.; Nichman, L.; Pinterich, T.; Prévôt, A. S. H.; Simon, M.; Slowik, J. G.; Steiner, G.; Tomé, A.; Vogel, A. L.; Volkamer, R.; Wagner, A. C.; Wagner, R.; Wexler, A. S.; Williamson, C.; Winkler, P. M.; Yan, C.; Amorim, A.; Dommen, J.; Curtius, J.; Gallagher, M. W.; Flagan, R. C.; Hansel, A.; Kirkby, J.; Kulmala, M.; Möhler, O.; Stratmann, F.; Worsnop, D. R.; Baltensperger, U.

    2016-02-01

    The growth of aerosol due to the aqueous phase oxidation of sulfur dioxide by ozone was measured in laboratory-generated clouds created in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN). Experiments were performed at 10 and -10 °C, on acidic (sulfuric acid) and on partially to fully neutralised (ammonium sulfate) seed aerosol. Clouds were generated by performing an adiabatic expansion - pressurising the chamber to 220 hPa above atmospheric pressure, and then rapidly releasing the excess pressure, resulting in a cooling, condensation of water on the aerosol and a cloud lifetime of approximately 6 min. A model was developed to compare the observed aerosol growth with that predicted using oxidation rate constants previously measured in bulk solutions. The model captured the measured aerosol growth very well for experiments performed at 10 and -10 °C, indicating that, in contrast to some previous studies, the oxidation rates of SO2 in a dispersed aqueous system can be well represented by using accepted rate constants, based on bulk measurements. To the best of our knowledge, these are the first laboratory-based measurements of aqueous phase oxidation in a dispersed, super-cooled population of droplets. The measurements are therefore important in confirming that the extrapolation of currently accepted reaction rate constants to temperatures below 0 °C is correct.

  12. 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

  14. Sulfur dioxide and nitrogen dioxide adsorption on zinc oxide and zirconium hydroxide nanoparticles and the effect on photoluminescence

    NASA Astrophysics Data System (ADS)

    Singh, Jagdeep; Mukherjee, Anupama; Sengupta, Sandip K.; Im, Jisun; Peterson, Gregory W.; Whitten, James E.

    2012-05-01

    Nanoparticulate zinc oxide and micron-size zirconium hydroxide powders have been exposed to sulfur dioxide and nitrogen dioxide by flowing the gases, diluted with nitrogen, over powder samples. X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and thermogravimetric analysis (TGA) indicate strongly bound, chemisorbed SO3 and NO3 surface species. Two pre-treatments of the nanoparticulate ZnO samples prior to gas exposure have been investigated: (1) drying overnight in a vacuum oven and (2) hydrating the samples by placing them overnight in water-saturated air. A dramatic difference in reactivity of ZnO is observed, with approximately two-fold and ten-fold greater uptake of NO2 and SO2, respectively, measured by XPS for the hydrated samples relative to the dried ones. Transmission electron microscopy (TEM) demonstrates that the greater uptake arises from a morphology change in the case of the hydrated samples. For zirconium hydroxide, no morphology change is observed for hydrated samples, and SO4 (ads), in addition to SO3 (ads), is indicated by XPS. ZnO and Zr(OH)4 both exhibit photoluminescence (PL) spectra, with peak intensities that change dramatically due to hydration and subsequent exposure to SO2 and NO2 gases. Dosing of the powders with these gases effectively reverts the PL spectra to those corresponding to less hydration.

  15. Synergistic action of tropospheric ozone and carbon dioxide on yield and nutritional quality of Indian mustard (Brassica juncea (L.) Czern.).

    PubMed

    Singh, Satyavan; Bhatia, Arti; Tomer, Ritu; Kumar, Vinod; Singh, B; Singh, S D

    2013-08-01

    Field experiments were conducted in open top chamber during rabi seasons of 2009-10 and 2010-11 at the research farm of the Indian Agricultural Research Institute, New Delhi to study the effect of tropospheric ozone (O3) and carbon dioxide (CO2) interaction on yield and nutritional quality of Indian mustard (Brassica juncea (L.) Czern.). Mustard plants were grown from emergence to maturity under different treatments: charcoal-filtered air (CF, 80-85 % less O3 than ambient O3 and ambient CO2), nonfiltered air (NF, 5-10 % less O3 than ambient O3 and ambient CO2 ), nonfiltered air with elevated carbon dioxide (NF + CO2, NF air and 550 ± 50 ppm CO2), elevated ozone (EO, NF air and 25-35 ppb elevated O3), elevated ozone along with elevated carbon dioxide (EO + CO2, NF air, 25-35 ppb O3 and 550 ± 50 ppm CO2), and ambient chamber less control (AC, ambient O3 and CO2). Elevated O3 exposure led to reduced photosynthesis and leaf area index resulting in decreased seed yield of mustard. Elevated ozone significantly decreased the oil and micronutrient content in mustard. Thirteen to 17 ppm hour O3 exposure (accumulated over threshold of 40 ppm, AOT 40) reduced the oil content by 18-20 %. Elevated CO2 (500 ± 50 ppm) along with EO was able to counter the decline in oil content in the seed, and it increased by 11 to 13 % over EO alone. Elevated CO2, however, decreased protein, calcium, zinc, iron, magnesium, and sulfur content in seed as compared to the nonfiltered control, whereas removal of O3 from air in the charcoal-filtered treatment resulted in a significant increase in the same.

  16. Ozone and nitrogen effects on yield and nutritive quality of the annual legume Trifolium cherleri

    NASA Astrophysics Data System (ADS)

    Sanz, J.; González-Fernández, I.; Calvete-Sogo, H.; Lin, J. S.; Alonso, R.; Muntifering, R.; Bermejo, V.

    2014-09-01

    Two independent experiments were performed in an Open-Top Chamber facility to determine the response of biomass and nutritive quality of the annual legume Trifolium cherleri to increased levels of ozone (O3) and nitrogen (N) deposition, two main drivers of global change. Plants growing in pots were exposed to three O3 treatments: charcoal-filtered air (CFA); non-filtered air, reproducing ambient O3 levels of the site (NFA); and non-filtered air supplemented with 40 nl l-1 (NFA+). Nitrogen was added in biweekly doses to achieve final doses of 5 (N5), 15 (N15) and 30 kg ha-1 (N30), reproducing the N deposition range in the Iberian Peninsula. Ozone negatively affected all the growth-related parameters and increased plant senescent biomass. The pollutant affected subterranean biomass to a greater extent than aerial biomass, resulting in altered aerial/subterranean ratio. Effects in the second experiment followed the same pattern as in the first, but were of lesser magnitude. However, these differences between assays could not be explained adequately by the absorbed O3 fluxes (Phytotoxic Ozone Dose, POD). Concentrations of cell-wall constituents related to nutritive quality increased with the O3 exposure, reducing the Relative Food Value index (RFV) that indicates decreased nutritive quality of the forage. Nitrogen stimulated all growth-related parameters, but increased the aboveground biomass more than the subterranean biomass. No effects of N fertilizer were detected for the nutritive quality parameters. A significant interaction between O3 and N was found in the second experiment. N further enhanced the increase of senescent biomass caused by O3. Results indicate that O3 is a potentially significant environmental stress factor in terms of structure and diversity of Mediterranean pastures.

  17. Temperature dependence of oxygen atom recombination in nitrogen after ozone photolysis

    NASA Astrophysics Data System (ADS)

    Smith, Gregory P.; Robertson, Robert

    2008-06-01

    Oxygen atom decays in nitrogen were measured by laser induced fluorescence following complete photodissociation of ozone at 248 nm. Rate coefficients determined for O + O + N2 are 2.5, 4.6, and 19.5 × 10-33 cm6/molecule2/s at 316, 262, and 171 K, with estimated 30% uncertainty. Results are in excellent agreement with the Baulch et al. [D.L. Baulch, D.D. Drysdale, J. Duxbury, S.J. Grant, Evaluated Kinetic Data for High Temperature Reactions, vol. 3, Butterworths, London, 1976, p. 33-64] recommended Arrhenius expression.

  18. 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.

  19. 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.

  20. On the role of nitrogen dioxide in the absorption of solar radiation

    NASA Astrophysics Data System (ADS)

    Solomon, S.; Portmann, R. W.; Sanders, R. W.; Daniel, J. S.; Madsen, W.; Bartram, B.; Dutton, E. G.

    1999-05-01

    Direct measurements of the absorption of downwelling visible radiation by nitrogen dioxide are presented. The data show that this gas can contribute significantly to local radiative forcing under certain conditions. The observed enhancements in nitrogen dioxide absorption are likely to be due both to pollution and to production by lightning in convective clouds. Case studies of several days of observations in Colorado reveal peak absorption of downwelling radiation by NO2 of up to 5-12%, corresponding to an estimated local radiative forcing that is likely to be in the range of 5-30 W/m2. The amount of local forcing associated with thunderstorm activity depends strongly upon the cloud optical depth and on where the NO2 resides within the clouds. These case studies suggest that NO2 can play a significant role in the absorption of radiation (including but not limited to anomalous cloud absorption) either under polluted conditions or when electrically active storms are considered.

  1. Alteration of extracellular enzymes in pinto bean leaves upon exposure to air pollutants, ozone and sulfur dioxide

    SciTech Connect

    Peters, J.L.; Castillo, F.J.; Heath, R.L. )

    1989-01-01

    Diamine oxidase and peroxidase, associated with the wall in pinto bean (Phaseolus vulgaris L. var Pinto) leaves, can be washed out by vacuum infiltration and assayed without grinding the leaf. The diamine oxidase activity is inhibited in vivo by exposure of the plants to ozone (dose of 0.6 microliters per liter {times} hour), whereas the peroxidase activity associated with the wall space is stimulated. This dose does not cause obvious necrosis or chlorosis of the leaf. These alterations are greater when the dose of ozone exposure is given as a triangular pulse (a slow rise to a peak of 0.24 microliters per liter followed by a slow fall) compared to that given as a constant square wave pulse of 0.15 microliters per liter for the same 4 hour period. Exposure of the plants to sulfur dioxide (at a concentration of 0.4 microliters per liter for 4 hours) does not result in any change in the diamine oxidase or peroxidase activities, yet the total sulfhydryl content of the leaf is increased, demonstrating the entry of sulfur dioxide. These two pollutants, with different chemical reactivities, affect the activities of the extracellular enzymes in different manners. In the case of ozone exposure, the inhibition of extracellular diamine oxidase could profoundly alter the movements of polyamines from cell to cell.

  2. Effect of disinfection of drinking water with ozone or chlorine dioxide on survival of Cryptosporidium parvum oocysts.

    PubMed Central

    Peeters, J E; Mazás, E A; Masschelein, W J; Villacorta Martiez de Maturana, I; Debacker, E

    1989-01-01

    Demineralized water was seeded with controlled numbers of oocysts of Cryptosporidium parvum purified from fresh calf feces and subjected to different treatments with ozone or chlorine dioxide. The disinfectants were neutralized by sodium thiosulfate, and neonatal mice were inoculated intragastrically and sacrificed 7 days later for enumeration of oocyst production. Preliminary trials indicated that a minimum infection level of 1,000 oocysts (0.1-ml inoculum) per mouse was necessary to induce 100% infection. Treatment of water containing 10(4) oocysts per ml with 1.11 mg of ozone per liter (concentration at time zero [C0]) for 6 min totally eliminated the infectivity of the oocysts for neonatal mice. A level of 2.27 mg of ozone per liter (C0) was necessary to inactivate water containing 5 x 10(5) oocysts per ml within 8 min. Also, 0.4 mg of chlorine dioxide per liter (C0) significantly reduced infectivity within 15 min of contact, although some oocysts remained viable. PMID:2764564

  3. Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone and Correction of SIP Approvals (76 FR 48208)

    EPA Pesticide Factsheets

    In this action, EPA limits the interstate transport of emissions of nitrogen oxides (NOX) and sulfur dioxide (SO2) that contribute to harmful levels of fine particle matter (PM2.5) and ozone in downwind states.

  4. 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.

  5. 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.

  6. 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 ...

  7. Fact Sheets and Additional Information Regarding the Primary National Ambient Air Quality Standards (NAAQS) for Nitrogen Dioxide (NO2)

    EPA Pesticide Factsheets

    Find tools for primary standards for Nitrogen Dioxide, maps of monitoring areas, an overview of the proposal, monitor requirements, design values for counties, and a presentation on the 2010 NO2 primary NAAQS revision.

  8. 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 ...

  9. Validation of nitrogen dioxide measurements from the Improved Stratospheric and Mesospheric Sounder

    NASA Astrophysics Data System (ADS)

    Reburn, W. J.; Remedios, J. J.; Morris, P. E.; Rodgers, C. D.; Taylor, F. W.; Kerridge, B. J.; Knight, R. J.; Ballard, J.; Kumer, J. B.; Massie, S. T.

    1996-04-01

    Measurements of nitrogen dioxide (NO2) from the Improved Stratospheric and Mesospheric Sounder (ISAMS) on the Upper Atmosphere Research Satellite (UARS) are assessed. Channel 5 of the instrument was dedicated to observations of nitrogen dioxide and employed pressure-modulation and wideband radiometry to make measurements at 6.2 μm. This dual technique allows simultaneous determination of nitrogen dioxide mixing ratio and the aerosol extinction coefficient at this wavelength and therefore provides nitrogen dioxide data even in the presence of heavy aerosol loading. Approximately 180 days of data, in the period from September 1991 to July 1992, were obtained with, typically, over 2600 profiles per day for each retrieved species, covering an altitude range of 100-0.01 mbar. In this paper the version 10 data are assessed and a full error analysis is described. Comparisons with the Cryogenic Limb Array Etalon Spectrometer (CLAES) on UARS and the Limb Infrared Monitor of the Stratosphere (LIMS) on Nimbus 7 are also presented. It is concluded that the morphology of the retrieved ISAMS fields is robust and consistent with concurrent as well as previous infrared satellite measurements. Random errors are estimated to be of the order of 10% for nighttime and 15% for daytime NO2 near the maxima of the distributions, and systematic errors are estimated to be of a similar size. However, there remains an unresolved systematic difference of about a factor of 2 between ISAMS and CLAES. Both random and systematic errors are likely to be reduced in future versions of the processing.

  10. 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.

  11. Traffic-related pollution and asthma prevalence in children. Quantification of associations with nitrogen dioxide.

    PubMed

    Favarato, Graziella; Anderson, H Ross; Atkinson, Richard; Fuller, Gary; Mills, Inga; Walton, Heather

    2014-01-01

    Ambient nitrogen dioxide is a widely available measure of traffic-related air pollution and is inconsistently associated with the prevalence of asthma symptoms in children. The use of this relationship to evaluate the health impact of policies affecting traffic management and traffic emissions is limited by the lack of a concentration-response function based on systematic review and meta-analysis of relevant studies. Using systematic methods, we identified papers containing quantitative estimates for nitrogen dioxide and the 12 month period prevalence of asthma symptoms in children in which the exposure contrast was within-community and dominated by traffic pollution. One estimate was selected from each study according to an a priori algorithm. Odds ratios were standardised to 10 μg/m(3) and summary estimates were obtained using random- and fixed-effects estimates. Eighteen studies were identified. Concentrations of nitrogen dioxide were estimated for the home address (12) and/or school (8) using a range of methods; land use regression (6), study monitors (6), dispersion modelling (4) and interpolation (2). Fourteen studies showed positive associations but only two associations were statistically significant at the 5 % level. There was moderate heterogeneity (I(2) = 32.8 %) and the random-effects estimate for the odds ratio was 1.06 (95 % CI 1.00 to 1.11). There was no evidence of small study bias. Individual studies tended to have only weak positive associations between nitrogen dioxide and asthma prevalence but the summary estimate bordered on statistical significance at the 5 % level. Although small, the potential impact on asthma prevalence could be considerable because of the high level of baseline prevalence in many cities. Whether the association is causal or indicates the effects of a correlated pollutant or other confounders, the estimate obtained by the meta-analysis would be appropriate for estimating impacts of traffic pollution on asthma

  12. Breadboard gas filter correlation spectrometer for atmospheric measurement of hydrazines and nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Dick, R.

    1981-10-01

    This report describes the efforts to build a breadboard Gas Filter Correlation Spectrometer (GFSC) for the atmospheric measurement of hydrazines and nitrogen dioxide. The instrument was configured for use as an ambient monitor, with the possibility of conversion to a remote sensor by addition of a telescope. The final detection limits for the gases were: N2H4 = .3 ppm, UDHM = .23 ppm, MMH = .22 ppm, and N02 = 9 ppm.

  13. Photodissociation of nitrogen dioxide by pulsed laser light at 6943 A.

    NASA Technical Reports Server (NTRS)

    Gerstmayr, J. W.; Harteck, P.; Reeves, R. R.

    1972-01-01

    Nitrogen dioxide was photodissociated using a pulsed ruby laser at 6943 A. The energy of a single photon at this wavelength was equivalent to only 57% of the dissociation energy. The mechanism proposed to account for the results was the consecutive absorption of two photons, the first resulting in a short-lived excited state. The second photon is then absorbed by the excited species resulting in dissociation.

  14. Nitrogen dioxide fluorescence from N/sub 2/O/sub 5/ photolysis

    SciTech Connect

    Oh, D.; Sisk, W.; Young, A.; Johnston, H.

    1986-12-15

    The products of ultraviolet photolysis of N/sub 2/O/sub 5/ are NO/sub 3/ and awavelength dependent mixture of NO/sub 2/, NO/sup *//sub 2/, and NO+O, where NO/sup *//sub 2/ represents one or more excited electronic states of nitrogen dioxide. This NO/sup *//sub 2/ emits the visible fluorescence spectrum of nitrogen dioxide (photolysis induced fluorescence, PIF), and this spectrum was compared with monochromatically excited NO/sub 2/ fluorescence spectra (laser induced fluorescence, LIF). In a series of experiments, dispersed PIF and LIF spectra were measured where reactant pressure was 200 mTorr, delay time was 30 ns, and observation time was 600 ns. According to results obtained by Sugimoto and co-workers, under these conditions the continuous spectrum, which reflects the overall internal energy of NO/sup *//sub 2/, had been little modified by collision, although there was degradation of fine structure. The continuous LIF spectra were fit to an empirical function, and the PIF spectra were shown to be well represented by a linear combination of these mono-energetic excitation spectra. The coefficients of this linear combination plus other considerations were interpreted to give the almost nascent internal energy distribution of the electronically excited nitrogen dioxide molecules produced by N/sub 2/O/sub 5/ photolysis. This non-Boltzmann internal energy distribution indicates that electronically excited nitrogen dioxide is produced in the /sup 2/B/sub 1/ state when N/sub 2/O/sub 5/ is photolyzed.

  15. Personal exposure monitoring of particulate matter, nitrogen dioxide, and carbon monoxide, including susceptible groups.

    PubMed

    Harrison, R M; Thornton, C A; Lawrence, R G; Mark, D; Kinnersley, R P; Ayres, J G

    2002-10-01

    To investigate the relation between personal exposures to nitrogen dioxide, carbon monoxide, and PM(10), and exposures estimated from static concentrations of these pollutants measured within the same microenvironments, for healthy individuals and members of susceptible groups. Eleven healthy adult subjects and 18 members of groups more susceptible to adverse health changes in response to a given level of exposure to nitrogen dioxide, carbon monoxide, and/or PM(10) than the general population (six schoolchildren, six elderly subjects, and six with pre-existing disease-two with chronic obstructive pulmonary disease (COPD), two with left ventricular failure (LVF), and two with severe asthma) were recruited. Daytime personal exposures were determined either directly or through shadowing. Relations between personal exposures and simultaneously measured microenvironment concentrations were examined. Correlations between personal exposures and microenvironment concentration were frequently weak for individual subjects because of the small range in measured concentrations. However, when all subjects were pooled, excellent relations between measured personal exposure and microenvironment concentration were found for both carbon monoxide and nitrogen dioxide, with slopes of close to one and near zero intercepts. For PM(10), a good correlation was also found with an intercept of personal exposure (personal cloud) of 16.7 (SD 10.4) micro g/m(3). Modelled and measured personal exposures were generally in reasonably good agreement, but modelling with generic mean microenvironment data was unable to represent the full range of measured concentrations. Microenvironment measurements of carbon monoxide and nitrogen dioxide can well represent the personal exposures of individuals within that microenvironment. The same is true for PM(10) with the addition of a personal cloud increment. Elderly subjects and those with pre-existing disease received generally lower PM(10) exposures than

  16. Dynamics of ozone and nitrogen oxides at Summit, Greenland. II. Simulating snowpack chemistry during a spring high ozone event with a 1-D process-scale model

    NASA Astrophysics Data System (ADS)

    Murray, Keenan A.; Kramer, Louisa J.; Doskey, Paul V.; Ganzeveld, Laurens; Seok, Brian; Van Dam, Brie; Helmig, Detlev

    2015-09-01

    Observed depth profiles of nitric oxide (NO), nitrogen dioxide (NO2), and ozone (O3) in snowpack interstitial air at Summit, Greenland were best replicated by a 1-D process-scale model, which included (1) geometrical representation of snow grains as spheres, (2) aqueous-phase chemistry confined to a quasi-liquid layer (QLL) on the surface of snow grains, and (3) initialization of the species concentrations in the QLL through equilibrium partitioning with mixing ratios in snowpack interstitial air. A comprehensive suite of measurements in and above snowpack during a high O3 event facilitated analysis of the relationship between the chemistry of snowpack and the overlying atmosphere. The model successfully reproduced 2 maxima (i.e., a peak near the surface of the snowpack at solar noon and a larger peak occurring in the evening that extended down from 0.5 to 2 m) in the diurnal profile of NO2 within snowpack interstitial air. The maximum production rate of NO2 by photolysis of nitrate (NO3-) was approximately 108 molec cm-3 s-1, which explained daily observations of maxima in NO2 mixing ratios near solar noon. Mixing ratios of NO2 in snowpack interstitial air were greatest in the deepest layers of the snowpack at night and were attributed to thermal decomposition of peroxynitric acid, which produced up to 106 molec NO2 cm-3 s-1. Highest levels of NO in snowpack interstitial air were confined to upper layers of the snowpack and observed profiles were consistent with photolysis of NO2. Production of nitrogen oxides (NOx) from NO3- photolysis was estimated to be two orders of magnitude larger than NO production and supports the hypothesis that NO3- photolysis is the primary source of NOx within sunlit snowpack in the Arctic. Aqueous-phase oxidation of formic acid by O3 resulted in a maximum consumption rate of ∼106-107 molec cm-3 s-1 and was the primary removal mechanism for O3.

  17. Global Airborne Observations of Nitrogen Oxides and Ozone from the Atmospheric Tomography Mission

    NASA Astrophysics Data System (ADS)

    Thompson, C. R.; Peischl, J.; Ryerson, T. B.

    2016-12-01

    The Atmospheric Tomography (ATom) Mission is an ambitious airborne field campaign that will conduct measurements of an extensive suite of trace gases and aerosols from the NASA DC-8 platform over three years and four seasons. Flights will travel nearly pole-to-pole, traversing both the Pacific and Atlantic Oceans, while profiling continuously from 0.2 to 12 km altitude to provide nearly global-scale observations of greenhouse gases and reactive species. Measurements from ATom will provide an unprecedented test for current global chemistry-climate models (CCMs) and will inform further improvements to these models. In particular, reactive species, such as ozone, are difficult to represent accurately in CCMs. We will present global observations of reactive nitrogen compounds (NO, NO2, NOy) and ozone from the first deployment of the ATom Mission in August of 2016. Flights will intercept a wide variety of air masses with different pollution signatures, including aged biomass burning emissions from Siberian wildfires and anthropogenic outflow from the Asian mainland, which will contrast the relatively clean background atmosphere encountered in the high latitudes of the Northern and Southern Hemispheres. We will compare the composition of the NOy budgets across these variety of air masses and impacts on ozone.

  18. The Carbon-Nitrogen Balance of the Nodule and Its Regulation under Elevated Carbon Dioxide Concentration

    PubMed Central

    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. PMID:24987690

  19. 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.

  20. Acute respiratory illness in families exposed to nitrogen dioxide ambient air pollution in Chattanooga, Tennessee

    SciTech Connect

    Love, G.J.; Lan, S.P.; Shy, C.M.; Riggan, W.B.

    1982-03-01

    The incidence of acute respiratory illness in families in Chattanooga, Tennessee was studied in 1972 and 1973 to determine if residents of a formerly high nitrogen dioxide exposure community continued to experience a high incidence of illness after ambient air concentrations of the pollutant had been reduced substantially. Illness data were collected by telephone at 2-wk intervals and illness rates per 100 person weeks of observation were contrasted with air pollution concentrations measured no more than 3.2 km from the home. Data were contrasted by communities designated as high, intermediate, or low pollution exposure. In 1972, higher rates of respiratory illness continued to occur in the designated high pollution area. These were associated with current higher short-term concentrations of nitrogen dioxide even though the long-term mean concentrations of the pollutant were little higher than those in the low pollution area. It was not possible to attribute the excesses in illness to specific pollutants or to specific exposure periods. However, reduction of the illness rate in 1973 associated with a strike at the primary source industry that curtailed nitrogen dioxide pollution in the high exposure community suggested that the short-term exposure may be more important than long-term exposure.

  1. A survey of carbon monoxide and nitrogen dioxide in indoor ice arenas in Vermont

    SciTech Connect

    Paulozzi, L.J. ); Spengler, R.F.; Vogt, R.L.; Carney, J.K.

    1993-12-01

    Because of the history of health problems traceable to the exhaust of ice resurfacing machines, state sanitarians used detector tubes to measure carbon monoxide (CO) and nitrogen dioxide (NO[sub 2]) levels in enclosed ice arenas in Vermont during high school hockey games. Five of eight arenas had average game CO measurements of 30 ppm carbon monoxide or more. Two of the three periods of play had average CO readings in excess of 100 ppm in one arena. Only six arenas had the complete series of nitrogen dioxide measurements. One had an average game NO[sub 2] level of 1.2 ppm. Two had one or more periods of play that averaged in excess of 0.5 ppm. Despite the ample documentation of the hazards of operating combustion-powered resurfacing machines inside enclosed ice arenas, a significant portion of the arenas had undesirable levels of carbon monoxide or nitrogen dioxide. Ice arenas should be routinely monitored for air contaminants. Considerations should be given to the purchase of electric ice resurfacing machines for new arenas and arenas that have air contamination that cannot be resolved with ventilation.

  2. Ozone and carbon dioxide effects on spider mites in white clover and peanut

    SciTech Connect

    Heagle, A.S.; Brandenburg, R.L.; Burns, J.C.; Miller, J.E.

    1994-11-01

    Effects of O{sub 3} and/or elevated CO{sub 2} on two-spotted spider mites (Tetranychus urticae Koch) grown on an O{sub 3}-sensitive and an O{sub 3}-resistant clone of white clover (Trifolium repens L.) were measured in greenhouse and field experiments. Peanut (Arachis hypogeae L.) {open_quote}NC-9{close_quote} was used in one greenhouse study with O{sub 3}. In field studies, O{sub 3} treatments were charcoal filtered air (CF), nonfiltered air (NF), and two NF treatments with O{sub 3} added for 12 h d{sup {minus}1} at proportions of {approx} 1.25 and 1.50 times the ambient O{sub 3} concentration. In greenhouse studies, constant amounts of O{sub 3} were added to CF for 6 h d{sup {minus}1} to achieve mean concentrations ranging from 5 to 100 nL L{sup {minus}1}. For the greenhouse O{sub 3} x CO{sub 2} experiment, CO{sub 2} concentrations were ambient and approximately twice-ambient for 24 h d{sup {minus}1}. Plants were exposed to O{sub 3} and/or CO{sub 2} for {approx} 7 d before infestation with mites; daily exposures continued for 14 to 28 d to allow reproduction for at least two generations. Leaves were sampled to count eggs, larvae, nymphs, and adults. Ozone caused more chlorosis and necrosis on the O{sub 3}-sensitive clover clone (NC-S) than on the O{sub 3}-resistant clone (NC-R). Carbon dioxide enrichment increased shoot growth of both clones by {approx}33%. Statistical analyses indicated significant O{sub 3} effects in some experiments and nonsignificant O{sub 3} effects in others. A trend toward increased mite populations with increased O{sub 3} occurred, however, on NC-S in all trials. No consistent trends occurred with NC-R. With peanut, a significant linear increase in mite population occurred with increased O{sub 3}. Carbon dioxide enrichment increased the rate of population increase on both clover clones, but more so on NC-R. 47 refs., 2 figs., 7 tabs.

  3. Effects of elevated atmospheric carbon dioxide on soil nitrogen cycling

    NASA Astrophysics Data System (ADS)

    Hofmockel, Kirsten S.

    elevated atmospheric CO2 on soil nitrogen cycling at the ecosystem scale, despite an increase in N demand of 0.86 g m-2 y -1 under elevated CO2. My results suggest that elevated CO2 does not alter soil nitrogen cycling at the decadal time scale. Retranslocation within trees and slowly cycling soil organic pools are likely supporting the increased N demand under elevated CO2. Longer-term studies may reveal differences in soil organic matter and carbon sequestration dynamics under ambient and elevated CO2.

  4. The Antarctic ozone minimum - Relationship to odd nitrogen, odd chlorine, the final warming, and the 11-year solar cycle

    NASA Technical Reports Server (NTRS)

    Callis, L. B.; Natarajan, M.

    1986-01-01

    Photochemical calculations along 'diabatic trajectories' in the meridional phase are used to search for the cause of the dramatic springtime minimum in Antarctic column ozone. The results indicate that the minimum is principally due to catalytic destruction of ozone by high levels of total odd nitrogen. Calculations suggest that these levels of odd nitrogen are transported within the polar vortex and during the polar night from the middle to upper stratosphere and lower mesosphere to the lower stratosphere. The possibility that these levels are related to the 11-year solar cycle and are increased by enhanced formation in the thermosphere and mesosphere during solar maximum conditions is discussed.

  5. Soil nitrogen and ozone effects on growth, physiology, and nutrition of loblolly pine and yellow-poplar seedlings

    SciTech Connect

    Tjoelker, M.G.; Luxmoore, R.J.; Schwarz, O.J.

    1989-06-01

    The effects of soil nitrogen level and chronic ozone (O /sub 3/) stress on carbon and nutrient economy were investigated in loblolly pine (Pinus taeda L.) and yellow-poplar (Liriodendron tulipifera L). The objectives of the study were: (1) to compare the growth and biomass partitioning in seedlings in response to varied low-nitrogen forest soil treatments in combination with chronic ozone levels over one growing season and (2) to investigate seedling physiological responses, including water use efficiency (WUE), photosynthesis, fine root and leaf nitrate reductase activity (NRA), nutrient concentration, nutrient uptake, and nutrient use efficiency (NUE). 135 refs., 12 figs., 16 tabs.

  6. Projected carbon dioxide to increase grass pollen and allergen exposure despite higher ozone levels.

    PubMed

    Albertine, Jennifer M; Manning, William J; DaCosta, Michelle; Stinson, Kristina A; Muilenberg, Michael L; Rogers, Christine A

    2014-01-01

    One expected effect of climate change on human health is increasing allergic and asthmatic symptoms through changes in pollen biology. Allergic diseases have a large impact on human health globally, with 10-30% of the population affected by allergic rhinitis and more than 300 million affected by asthma. Pollen from grass species, which are highly allergenic and occur worldwide, elicits allergic responses in 20% of the general population and 40% of atopic individuals. Here we examine the effects of elevated levels of two greenhouse gases, carbon dioxide (CO2), a growth and reproductive stimulator of plants, and ozone (O3), a repressor, on pollen and allergen production in Timothy grass (Phleum pratense L.). We conducted a fully factorial experiment in which plants were grown at ambient and/or elevated levels of O3 and CO2, to simulate present and projected levels of both gases and their potential interactive effects. We captured and counted pollen from flowers in each treatment and assayed for concentrations of the allergen protein, Phl p 5. We found that elevated levels of CO2 increased the amount of grass pollen produced by ∼50% per flower, regardless of O3 levels. Elevated O3 significantly reduced the Phl p 5 content of the pollen but the net effect of rising pollen numbers with elevated CO2 indicate increased allergen exposure under elevated levels of both greenhouse gases. Using quantitative estimates of increased pollen production and number of flowering plants per treatment, we estimated that airborne grass pollen concentrations will increase in the future up to ∼200%. Due to the widespread existence of grasses and the particular importance of P. pratense in eliciting allergic responses, our findings provide evidence for significant impacts on human health worldwide as a result of future climate change.

  7. Pulmonary response to threshold levels of sulfur dioxide (1. 0 ppm) and ozone (0. 3 ppm)

    SciTech Connect

    Folinsbee, L.J.; Bedi, J.F.; Horvath, S.M.

    1985-06-01

    The authors exposed 22 healthy adult nonsmoking male subjects for 2 h to filtered air, 1.0 ppm sulfur dioxide (SO/sub 2/), 0.3 ppm ozone (O/sub 3/), or the combination of 1.0 ppm SO/sub 2/ + 0.3 ppm O/sub 3/. They hypothesized that exposure to near-threshold concentrations of these pollutants would allow them to observe any interaction between the two pollutants that might have been masked by the more obvious response to the higher concentrations of O/sub 3/ used in previous studies. Each subject alternated 30-min treadmill exercise with 10-min rest periods for the 2 h. The average exercise ventilation measured during the last 5 min of exercise was 38 1/min (BTPS). Forced expiratory maneuvers were performed before exposure and 5 min after each of the three exercise periods. Maximum voluntary ventilation, He dilution functional residual capacity, thoracic gas volume, and airway resistance were measured before and after the exposure. After O/sub 3/ exposure alone, forced expiratory measurements (FVC, FEV1.0, and FEF25-75%) were significantly decreased. The combined exposure to SO/sub 2/ + O/sub 3/ produced similar but smaller decreases in these measures. There were small but significant differences between the O/sub 3/ and the O/sub 3/ + SO/sub 2/ exposure for FVC, FEV1.0, FEV2.0, FEV3.0, and FEF25-75% at the end of the 2-h exposure. The authors conclude that, with these pollutant concentrations, there is no additive or synergistic effect of the two pollutants on pulmonary function.

  8. The combined effects of elevated carbon dioxide and ozone on crop systems

    SciTech Connect

    Miller, J.E.; Heagle, A.S.; Shafer, S.R.; Heck, W.W. |

    1994-12-31

    Concentrations of carbon dioxide (CO{sub 2}) and ozone (O{sub 3}) in the troposphere have risen in the last century due to industrialization. Current levels of tropospheric O{sub 3} suppress growth of crops and other plants, and O{sub 3} concentrations may continue to rise with changes in global climate. On the other hand, projected increases in atmospheric concentrations of CO{sub 2} in the next 50 to 100 years are expected to cause significant increases in growth of most species. Since elevated concentrations of these gases will co-occur, it is important to understand their joint action. Until recently, however, the combined effects of O{sub 3} and CO{sub 2} have received little attention. Most publications on combined CO{sub 2} and O{sub 3} effects have described experiments conducted in greenhouse or controlled-environment facilities. To date, data on responses of agricultural species to the combined gases have come from experiments with radish, tomato, white clover, tobacco, or wheat. In most cases, CO{sub 2} stimulated and O{sub 3} suppressed growth of the plant tissues studied, and CO{sub 2} usually attenuated development of O{sub 3}-induced visible injury. Some data have indicated a tendency for CO{sub 2}, in concentrations up to double the current ambient level, to attenuate effects of O{sub 3} on growth, but statistical analyses of such data often have not supported such a conclusion. In this paper, the results of a recent field experiment with soybean are reported, and the results are compared to other similar research with elevated atmospheric concentrations of both O{sub 3} and CO{sub 2}.

  9. Response of tomatoes to ozone, sulphur dioxide, and infection by Pratylenchus penetrans

    SciTech Connect

    Shew, B.B.; Reinert, R.A.; Barker, K.R.

    1982-01-01

    Tomato plants (Lycopersicon esculentum 'Walter') were inoculated with initial population densities of Pratylenchus penetrans ranging 0-4000 nematodes per pot and were repeatedly exposed to ozone (O/sub 3/). Exposures to charcoal-filtered air served as controls. Decreases in dry weights of plant parts excised from tomato plants exposed to 0.2 ..mu..l O/sub 3/ per liter of air added to the decrease in dry weight caused by exposure to sulfur dioxide (SO/sub 2/) at 0.2 ..mu..l/L of air adequately predicted the decrease in dry weight of tomato plants caused by exposure to 0.2 ..mu..l O/sub 3/ + 0.2 ..mu..l SO/sub 2/ per liter of air. When 0.2 ..mu..l O/sub 3/ and 0.8 ..mu..l SO/sub 2/ per liter of air were present in mixture, they acted antagonistically and caused less change in leaf and shoot dry weight than could be predicted by the main effects of O/sub 3/ or SO/sub 2/. The presence of P. penetrans attacking the roots enhanced the negative effects of O/sub 3/ + SO/sub 2/ on leaf growth (dry weight), but suppressed the inhibitory effects of O/sub 3/ + SO/sub 2/ on auxillary shoot dry weight. Treatments containing 0.8 ..mu..l SO/sub 2/ per liter of air reduced tomato fruit weight, but the amount of reduction was antagonized by the presence of O/sub 3/.

  10. Effects of carbon dioxide enrichment and nitrogen supply on growth of boreal tree seedlings.

    PubMed

    Brown, Kevin; Higginbotham, K. O.

    1986-12-01

    The effects of two levels of atmospheric carbon dioxide (350 microl l(-1), 750 microl l(-1)) and three levels of nitrogen (15.5 mM, 1.55 mM, 0.155 mM N) on biomass accumulation and partitioning were examined in aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) seedlings grown in controlled environment rooms for 100 days after germination. Nitrogen supply had pronounced effects on biomass accumulation, height, and leaf area of both species. Root weight ratio (RWR) of white spruce was significantly increased at the lowest level of nitrogen, whereas RWR of aspen did not change much with increasing levels of nitrogen. Carbon dioxide enrichment significantly increased (1) the leaf and total biomass of spruce seedlings grown in the high-N regime, (2) the RWR of seedlings in the medium-N regime, and (3) the root biomass of seedlings in the low-N regime after 100 days. Carbon dioxide enrichment of aspen temporarily increased biomass and height in all three nitrogen regimes. Root, stem, and leaf mass, height, and leaf area of aspen were increased only at the 30-day harvest in the high-N treatment and at 50 and 60 days in the low-N treatment. Height, stem biomass, and leaf biomass of aspen seedlings were significantly increased by CO(2) enrichment after 40 days in the medium-N treatment. These effects did not persist, possibly because of the onset of mineral nutrient supply limitations with increasing plant size.

  11. Field assessment of a snap bean ozone bioindicator system under elevated ozone and carbon dioxide in a free air system

    USDA-ARS?s Scientific Manuscript database

    Ozone-sensitive (S156) and -tolerant (R123 and R331) genotypes of snap bean (Phaseolus vulgaris L.) were tested as a plant bioindicator system for detecting O3 effects at current and future levels of tropospheric O3 and atmospheric CO2 under field conditions. Plants were exposed to reciprocal combi...

  12. Improvements in the profiles and distributions of nitric acid and nitrogen dioxide with the LIMS version 6 dataset

    NASA Astrophysics Data System (ADS)

    Remsberg, E.; Natarajan, M.; Marshall, T.; Gordley, L. L.; Thompson, R. E.; Lingenfelser, G.

    2010-02-01

    The quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) nitric acid (HNO3) and nitrogen dioxide (NO2) profiles and distributions of 1978/1979 is described after their processing with an updated, Version 6 (V6) algorithm and subsequent archival in 2002. Estimates of the precision and accuracy of both of those species are developed and provided herein. The character of the V6 HNO3 profiles is relatively unchanged from that of the earlier LIMS Version 5 (V5) profiles, except in the upper stratosphere where the interfering effects of CO2 are accounted for better with V6. The accuracy of the retrieved V6 NO2 is also significantly better in the middle and upper stratosphere, due to improvements in its spectral line parameters and in the reduced biases for the accompanying V6 temperature and water vapor profiles. As a result of these important updates, there is better agreement with theoretical calculations for profiles of the HNO3/NO2 ratio, day-to-night NO2 ratio, and with estimates of the production of NO2 in the mesosphere and its descent to the upper stratosphere during polar night. The improved precisions and more frequent retrievals of the profiles along the LIMS orbit tracks provide for better continuity and detail in map analyses of these two species on pressure surfaces. It is judged that the chemical effects of the oxides of nitrogen on ozone can be examined quantitatively throughout the stratosphere with the LIMS V6 data, and that the findings will be more compatible with those obtained from measurements of the same species from subsequent satellite sensors.

  13. Improvements in the profiles and distributions of nitric acid and nitrogen dioxide with the LIMS version 6 dataset

    NASA Astrophysics Data System (ADS)

    Remsberg, E.; Natarajan, M.; Marshall, B. T.; Gordley, L. L.; Thompson, R. E.; Lingenfelser, G.

    2010-05-01

    The quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) nitric acid (HNO3) and nitrogen dioxide (NO2) profiles and distributions of 1978/1979 are described after their processing with an updated, Version 6 (V6) algorithm and subsequent archival in 2002. Estimates of the precision and accuracy of both of those species are developed and provided herein. The character of the V6 HNO3 profiles is relatively unchanged from that of the earlier LIMS Version 5 (V5) profiles, except in the upper stratosphere where the interfering effects of CO2 are accounted for better with V6. The accuracy of the retrieved V6 NO2 is also significantly better in the middle and upper stratosphere, due to improvements in its spectral line parameters and in the reduced biases for the accompanying V6 temperature and water vapor profiles. As a result of these important updates, there is better agreement with theoretical calculations for profiles of the HNO3/NO2 ratio, day-to-night NO2 ratio, and with estimates of the production of NO2 in the mesosphere and its descent to the upper stratosphere during polar night. In particular, the findings for middle and upper stratospheric NO2 should also be more compatible with those obtained from more recent satellite sensors because the effects of the spin-splitting of the NO2 lines are accounted for now with the LIMS V6 algorithm. The improved precisions and more frequent retrievals of the LIMS profiles along their orbit tracks provide for better continuity and detail in map analyses of these two species on pressure surfaces. It is judged that the chemical effects of the oxides of nitrogen on ozone can be studied quantitatively throughout the stratosphere with the LIMS V6 data.

  14. Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China.

    PubMed

    Seow, W J; Downward, G S; Wei, H; Rothman, N; Reiss, B; Xu, J; Bassig, B A; Li, J; He, J; Hosgood, H D; Wu, G; Chapman, R S; Tian, L; Wei, F; Caporaso, N E; Vermeulen, R; Lan, Q

    2016-10-01

    The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation in the rural counties of Xuanwei and Fuyuan, in Yunnan Province, China, which have among the highest lung cancer rates in the nation, a total of 163 participants in 30 selected villages were enrolled. Indoor 24-h NO2 and SO2 samples were collected in each household over two consecutive days. Compared to smoky coal, smokeless coal use was associated with higher NO2 concentrations [geometric mean (GM) = 132 μg/m(3) for smokeless coal and 111 μg/m(3) for smoky coal, P = 0.065] and SO2 [limit of detection = 24 μg/m(3) ; percentage detected (%Detect) = 86% for smokeless coal and 40% for smoky coal, P < 0.001]. Among smoky coal users, significant variation of NO2 and SO2 air concentrations was observed across different stove designs and smoky coal sources in both counties. Model construction indicated that the measurements of both pollutants were influenced by stove design. This exposure assessment study has identified high levels of NO2 and SO2 as a result of burning solid fuels for cooking and heating.

  15. Assessing Day-to Day Variability in the Vertical Distribution of Methane, Carbon Dioxide, and Ozone over Railroad Valley, NV

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Johnson, M. S.; Yates, E. L.; Tanaka, T.; Sweeney, C.; Tadic, J.; Roby, M.; Andrews, A. E.; Lopez, J. P.

    2013-12-01

    In-situ observations of three trace gases over a remote desert site allow for an analysis of the variability of ozone (O3), methane (CH4), and carbon dioxide (CO2) in the free troposphere. Observations from June 2013 show almost no change from one day to the next in the boundary layer (BL) up to > 4 km (30% of the atmospheric column), while mixing ratios of methane and carbon dioxide show strong variability above this altitude. Ozone values also demonstrate variability above the boundary layer, and ozone day-to-day variability in the well-mixed BL is greater than that of CO2 or CH4. Results from week-long intensives in both June 2012 and June 2013, as well as monthly measurements over the period 2012-2013, will be compared to long-term vertical profile data sets at other locations (Trinidad Head, CA; Briggsdale, CO; and the Southern Great Plains site, OK). Variability above and in the boundary layer will be reported. To assess possible sources of variability, in situ data will be analyzed with a chemical trajectory model (GEOS-Chem v9-01-03). The North America nested-grid version of GEOS-Chem utilizes varying emission inventories and model parameterizations to simulate the emissions of greenhouse gases (CO2 and CH4, in this case) and ozone precursor gases. Tagged tracer simulations in GEOS-Chem allow for the geographical source apportionment of ozone, indicating whether the observed O3 was formed in the upper troposphere, middle troposphere, stratosphere, or any user-defined boundary layer location. For this study we will focus on ozone formed in the boundary layer over Asia, the Pacific Ocean, Mexico, Canada, and the United States. The importance of daily variability in the free tropospheric values of CO2, CH4, and O3 will be discussed in the context of column measurements collected from the surface or from space. Many data assimilation systems are designed to assume that changes to the total column average should be attributed primarily to changes within the

  16. BVOC responses to realistic nitrogen fertilization and ozone exposure in silver birch.

    PubMed

    Carriero, G; Brunetti, C; Fares, S; Hayes, F; Hoshika, Y; Mills, G; Tattini, M; Paoletti, E

    2016-06-01

    Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha(-1) yr(-1), applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area. Copyright © 2016. Published by Elsevier Ltd.

  17. Kinetics of the formation of ozone and nitrogen oxides due to a pulsed microwave discharge in air

    NASA Astrophysics Data System (ADS)

    Larin, V. F.; Rumiantsev, S. A.

    1989-03-01

    The paper presents results of a numerical simulation of the kinetics of plasma-chemical processes induced by a single microwave pulse in the stratosphere. It is shown that the gas temperature is one of the main factors influencing the concentration ratio of ozone and nitrogen oxides formed under the effect of a microwave pulse. Long pulses, producing considerable gas heating, favor the formation of nitrogen oxides.

  18. 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.

  19. Effect of nitrogen addition to ozone generation characteristics by diffuse and filamentary dielectric barrier discharges at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Osawa, Naoki; Tsuji, Takafumi; Ogiso, Ryota; Yoshioka, Yoshio

    2017-05-01

    Ozone is widely used for gas treatment, advanced oxidation processes, microorganisms inactivation, etc. In this research, we investigated the effect of nitrogen addition to ozone generation characteristics by atmospheric pressure Townsend discharge (APTD) type and filamentary dielectric barrier discharge (DBD) type ozone generators. The result showed that the ozone generated by the filamentary DBD increases rapidly with the increase of O2 content, and is higher than that by the APTD. On the other hand, it is interesting that the ozone generated by the APTD gradually decreases with the increase of O2 content. In order to clarify why the characteristics of ozone generation by the two kinds of discharge modes showed different dependency to the N2 content, we analyzed the exhaust gas composition using FTIR spectroscopy and calculated the rate coefficients using BOLSIG+ code. As a result, we found that although O2 content decreased with increasing N2 content, additional O atoms produced by excited N2 molecules contribute to ozone generation in case of APTD. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  20. Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone.

    PubMed

    Pregitzer, Kurt; Loya, Wendy; Kubiske, Mark; Zak, Donald

    2006-06-01

    The aspen free-air CO2 and O3 enrichment (FACTS II-FACE) study in Rhinelander, Wisconsin, USA, is designed to understand the mechanisms by which young northern deciduous forest ecosystems respond to elevated atmospheric carbon dioxide (CO2) and elevated tropospheric ozone (O3) in a replicated, factorial, field experiment. Soil respiration is the second largest flux of carbon (C) in these ecosystems, and the objective of this study was to understand how soil respiration responded to the experimental treatments as these fast-growing stands of pure aspen and birch + aspen approached maximum leaf area. Rates of soil respiration were typically lowest in the elevated O3 treatment. Elevated CO2 significantly stimulated soil respiration (8-26%) compared to the control treatment in both community types over all three growing seasons. In years 6-7 of the experiment, the greatest rates of soil respiration occurred in the interaction treatment (CO2 + O3), and rates of soil respiration were 15-25% greater in this treatment than in the elevated CO2 treatment, depending on year and community type. Two of the treatments, elevated CO2 and elevated CO2 + O3, were fumigated with 13C-depleted CO2, and in these two treatments we used standard isotope mixing models to understand the proportions of new and old C in soil respiration. During the peak of the growing season, C fixed since the initiation of the experiment in 1998 (new C) accounted for 60-80% of total soil respiration. The isotope measurements independently confirmed that more new C was respired from the interaction treatment compared to the elevated CO2 treatment. A period of low soil moisture late in the 2003 growing season resulted in soil respiration with an isotopic signature 4-6 per thousand enriched in 13C compared to sample dates when the percentage soil moisture was higher. In 2004, an extended period of low soil moisture during August and early September, punctuated by a significant rainfall event, resulted in soil

  1. Yield vs. quality trade-offs for wheat in response to carbon dioxide and ozone.

    PubMed

    Pleijel, Håkan; Uddling, Johan

    2011-07-06

    Although it is established that there exist potential trade-offs between grain yield and grain quality in wheat exposed to elevated carbon dioxide (CO2 ) and ozone (O3 ), their underlying causes remain poorly explored. To investigate the processes affecting grain quality under altered CO2 and O3 , we analysed 57 experiments with CO2 or O3 exposure in different exposure systems. The study covered 24 cultivars studied in 112 experimental treatments from 11 countries. A significant growth dilution effect on grain protein was found: a change in grain yield of 10% by O3 was associated with a change in grain protein yield of 8.1% (R(2) =0.96), while a change in yield effect of 10% by CO2 was linked to a change in grain protein yield effect of 7.5% (R(2) =0.74). Superimposed on this effect, elevated CO2 , but not O3 , had a significant negative effect on grain protein yield also in the absence of effects on grain yield, indicating that there exists a process by which CO2 restricts grain protein accumulation, which is absent for O3 . Grain mass, another quality trait, was more strongly affected by O3 than grain number, while the opposite was true for CO2 . Harvest index was strongly and negatively influenced by O3 , but was unaffected by CO2 . We conclude that yield vs. protein trade-offs for wheat in response to CO2 and O3 are constrained by close relationships between effects on grain biomass and less than proportional effects on grain protein. An important and novel finding was that elevated CO2 has a direct negative effect on grain protein accumulation independent of the yield effect, supporting recent evidence of CO2 -induced impairment of nitrate uptake/assimilation. Finally, our results demonstrated that processes underlying responses of grain yield vs. quality trade-offs are very different in wheat exposed to elevated O3 compared to elevated CO2 . © 2011 Blackwell Publishing Ltd.

  2. 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.

  3. 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

  4. Ozone impacts on vegetation in a nitrogen enriched and changing climate.

    PubMed

    Mills, Gina; Harmens, Harry; Wagg, Serena; Sharps, Katrina; Hayes, Felicity; Fowler, David; Sutton, Mark; Davies, Bill

    2016-01-01

    This paper provides a process-oriented perspective on the combined effects of ozone (O3), climate change and/or nitrogen (N) on vegetation. Whereas increasing CO2 in controlled environments or open-top chambers often ameliorates effects of O3 on leaf physiology, growth and C allocation, this is less likely in the field. Combined responses to elevated temperature and O3 have rarely been studied even though some critical growth stages such as seed initiation are sensitive to both. Under O3 exposure, many species have smaller roots, thereby enhancing drought sensitivity. Of the 68 species assessed for stomatal responses to ozone, 22.5% were unaffected, 33.5% had sluggish or increased opening and 44% stomatal closure. The beneficial effect of N on root development was lost at higher O3 treatments whilst the effects of increasing O3 on root biomass became more pronounced as N increased. Both responses to gradual changes in pollutants and climate and those under extreme weather events require further study.

  5. The Effect of Global Change on Surface Ozone and Reactive Nitrogen Concentrations: Implications for the Biosphere

    NASA Astrophysics Data System (ADS)

    Hess, P. G.; Murazaki, K.; Emmons, L.; Lamarque, J.

    2005-12-01

    We simulated two ten year periods using the global chemical transport model MOZART-2 (Model of Ozone and Related chemical Tracers version 2): 1990-2000 and 2090-2100. In each case MOZART-2 is driven by meteorology from the National Center for Atmospheric Research (NCAR) coupled Climate Systems Model (CSM) 1.0 forced with the (SRES) A1 scenario. Profound future changes in the summertime climate over the U.S. are found including changes in temperature, water vapor and clouds and the frequency of synoptic venting of the boundary layer. Even allowing for no changes in emissions in the future, the changes in climate alone drive a significant increase in the ozone concentration over the eastern U.S. (up to 5 ppbv on average) and an increase in the persistence of pollution events. Implications of these changes on the biosphere are assessed with and without allowing for the impact of climate on biogenic emissions. Furthermore the changes in climate alone cause large changes in the partitioning of NOy, decreasing PAN by over 20% over the U.S. Coupled with changes in precipitation; this induces significant changes in the deposition of nitrogen species to the biosphere in a future climate.

  6. Ozone sensitivity of the Mediterranean terophyte Trifolium striatum is modulated by soil nitrogen content

    NASA Astrophysics Data System (ADS)

    Sanz, Javier; Bermejo, Victoria; Gimeno, Benjamín S.; Elvira, Susana; Alonso, Rocío

    The influence of nitrogen (N) fertilization on the sensitivity to ozone (O 3) has been studied using the O 3 sensitive species Trifolium striatum, an annual species frequently found in therophitic grasslands of the dehesas in the central Iberian Peninsula. The experiment was carried out in open-top chambers using three different O 3 exposure treatments: charcoal-filtered air (CFA), non-filtered air (NFA) and non-filtered air plus 40 nl l -1 added over ambient concentrations (NFA+). After 30 days of exposure to the different treatments, plants were placed under ambient conditions until seed ripeness was completed. Three N fertilization treatments were established receiving final doses of 10 (low), 30 (medium) or 60 (high) kg N ha -1 throughout the growing period divided into four proportional doses at every 15 days. Ozone affected phenology and reduced total aerial and flower biomass and seed production in NFA and NFA+ treatments. Carry-over effects of O 3 on the reproductive ability of this species were found resulting in reductions in flower biomass and seed production detected 1 month after O 3 exposure. By contrast, N fertilization increased aerial and flower biomass. Significant O 3×N interactive effects were detected since N fertilization counterbalanced O 3-induced effects only when plants were exposed to moderate O 3 levels (NFA) but not under high O 3 concentrations (NFA+). The observed O 3 effects on reproductive ability of T. striatum might determine changes in species viability and future diversity of the ecosystem.

  7. Integrated assessment of the spatial variability of ozone impacts from emissions of nitrogen oxides

    SciTech Connect

    Daniel Q. Tong; Nicholas Z. Muller; Denise L. Mauzerall; Robert O. Mendelsohn

    2006-03-01

    This paper examines the ozone (O{sub 3}) damages caused by nitrogen oxides (NOx) emissions in different locations around the Atlanta metropolitan area during a summer month. Ozone impacts are calculated using a new integrated assessment model that links pollution emissions to their chemical transformation, transport, population exposures, and effects on human health. It was found that increased NOx emissions in rural areas around Atlanta increase human exposure to ambient O{sub 3} twice as much as suburban emissions. However, increased NOx emissions in central city Atlanta actually reduce O{sub 3} exposures. For downtown emissions, the reduction in human exposures to O{sub 3} from titration by NO in the central city outweighs the effects from increased downwind O{sub 3}. The results indicate that the marginal damage from NOx emissions varies greatly across a metropolitan area. The results raise concerns if cap and trade regulations cause emissions to migrate toward higher marginal damage locations. 22 refs., 4 figs., 2 tabs.

  8. Ozone and increased nitrogen supply effects on the yield and nutritive quality of Trifolium subterraneum

    NASA Astrophysics Data System (ADS)

    Sanz, J.; Muntifering, R. B.; Bermejo, V.; Gimeno, B. S.; Elvira, S.

    The influence of ambient ozone (O 3) concentrations and nitrogen (N) fertilization, singly and in combination, on the growth and nutritive quality of Trifolium subterraneum was assessed. This is an important O 3-sensitive species of great pastoral value in Mediterranean areas. Plant material was enclosed in open-top chambers (OTCs). Three O 3 levels were established: Filtered air with O 3 concentrations below 15 ppb (CFA), non-filtered air with O 3 concentrations in the range of ambient levels (NFA), and non-filtered air supplemented with 40 ppb O 3 over ambient levels (NFA+). Similarly, three N levels were defined: 5, 15 and 30 kg ha -1. The increase in O 3 exposure induced a reduction of the clover aerial green biomass and an increase of senescent biomass. Ozone effects were more adverse in the root system, inducing an impairment of the aerial/subterranean biomass ratio. Compared with the CFA treatment, nutritive quality of aerial biomass was 10 and 20% lower for NFA and NFA+ treatments, respectively, due to increased concentrations of acid detergent fiber, neutral detergent fiber and lignin. The latter effect appears to be related to senescence acceleration. The increment in N supplementation enhanced the increase of ADF concentrations in those plants simultaneously exposed to ambient and above-ambient O 3 concentrations, and reduced the incremental rate of foliar senescence induced by the pollutant.

  9. Integrated assessment of the spatial variability of ozone impacts from emissions of nitrogen oxides.

    PubMed

    Tong, Daniel Q; Muller, Nicholas Z; Mauzerall, Denise L; Mendelsohn, Robert O

    2006-03-01

    This paper examines the ozone (O3) damages caused by nitrogen oxides (NO(x)) emissions in different locations around the Atlanta metropolitan area during a summer month. We calculate O3 impacts using a new integrated assessment model that links pollution emissions to their chemical transformation, transport, population exposures, and effects on human health. We find that increased NO(x) emissions in rural areas around Atlanta increase human exposure to ambient O3 twice as much as suburban emissions. However, increased NO(x) emissions in central city Atlanta actually reduce O3 exposures. For downtown emissions, the reduction in human exposures to O3 from titration by NO in the central city outweighs the effects from increased downwind O3. The results indicate that the marginal damage from NO(x) emissions varies greatly across a metropolitan area. The results raise concerns if cap and trade regulations cause emissions to migrate toward higher marginal damage locations.

  10. Radiative lifetimes of nitrogen dioxide for excitation wavelengths from 400 to 750 nm

    SciTech Connect

    Patten, K.O. Jr.; Burley, J.D.; Johnston, H.S. )

    1990-10-04

    At room temperature, the radiative lifetimes of nitrogen dioxide excited by pulsed, tunable, dye laser radiation are measured in a 50-L flask, for excitation wavelengths ranging from 400 to 750 nm, at total pressures between 0.25 and 2.0 mTorr, and for times between 0.7 and 60 {mu}s. The data are analyzed in terms of the Stern-Volmer mechanism to give zero-pressure radiative constants (k{sub 0} = 1/{tau}{sub 0}) and empirical collisional quenching rate constants k{sub q} by ground-state nitrogen dioxide. (a) The observed radiative coefficients generally increase linearly with increasing excitation energy (cm{sup {minus}1}): k{sub 0}/s{sup {minus}1} = 0.504(E-E{sub 0}) + 7.96 {times} 10{sup 3}, where E is the excitation energy and E{sub 0} is the energy of the origin of the {sup 2}B{sub 2} excited state. At wavelengths above about 540 nm there are strong state-to-state variations of radiative lifetime, producing large apparent scatter in the data. The zero-pressure radiative lifetimes {tau}{sub 0} are compared to previous measurements and are in rough agreement with a number of earlier studies. (b) On the other hand, different investigators typically obtain different numerical values for the Stern-Volmer collisional quenching rate constants. As observed here, the quenching rate constants k{sub q} are found to vary by almost a factor of 6 as filters are changed in front of the photomultiplier tube with all other experimental conditions held constant. Some of the difficulties of observing meaningful quenching rate constants for nitrogen dioxide are discussed.

  11. Spectrophotometric determination of nitrogen dioxide in air and nitrite in water and soil samples

    SciTech Connect

    Pandurangappa, M.; Balasubramanian, N.

    1995-02-01

    A sensitive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite in water and soil samples is described. Nitrogen dioxide in air is fixed as nitrite ion in alkaline sodium arsenite or in triethanolamine absorber solutions. The method is based on the diazo coupling reaction between p-nitro aniline and 1-hydroxy-2-naphthoic acid. The azo dye formed under aqueous condition has an absorption maximum at 585nm and obeys Beer`s law over the range 0-25{mu}g of nitrite. The colour system is stable for 72h. The relative standard deviation is 2.7% for ten determinations at 15{mu}g of nitrite. The dye is extracted with 1:1 isoamyl alcohol-IBMK mixture and stabilisation with methanolic potassium hydroxide showed {lambda}{sub max} at 610nm. It obeys Beer`s law over the range 0-4{mu}g of nitrite. The colour system is stable for 40h in organic phase and the relative standard deviation is 2.5% for ten determinations at 3{mu}g of nitrite. The molar absorptivity of the colour system is 3.68 x 10{sup 4} Lmol{sup {minus}1} cm{sup {minus}1}. The effect of interfering gases and other ions on the determination of nitrite is described. The developed method has been applied for the determination of residual nitrogen dioxide gas present in the laboratory fume cupboard and automobile exhaust gases. In addition, the method has been applied for the determination of nitrite and nitrate in samples like water, soil and radiator coolants.

  12. 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.

  13. 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.

  14. Sources and sinks of atmospheric N2O and the possible ozone reduction due to industrial fixed nitrogen fertilizers

    NASA Technical Reports Server (NTRS)

    Liu, S. C.; Cicerone, R. J.; Donahue, T. M.; Chameides, W. L.

    1977-01-01

    The terrestrial and marine nitrogen cycles are examined in an attempt to clarify how the atmospheric content of N2O is controlled. We review available data on the various reservoirs of fixed nitrogen, the transfer rates between the reservoirs, and estimate how the reservoir contents and transfer rates can change under man's influence. It is seen that sources, sinks and lifetime of atmospheric N2O are not understood well. Based on our limited knowledge of the stability of atmospheric N2O we conclude that future growth in the usage of industrial fixed nitrogen fertilizers could cause a 1% to 2% global ozone reduction in the next 50 years. However, centuries from now the ozone layer could be reduced by as much as 10% if soils are the major source of atmospheric N2O.

  15. Sources and sinks of atmospheric N2O and the possible ozone reduction due to industrial fixed nitrogen fertilizers

    NASA Technical Reports Server (NTRS)

    Liu, S. C.; Cicerone, R. J.; Donahue, T. M.; Chameides, W. L.

    1977-01-01

    The terrestrial and marine nitrogen cycles are examined in an attempt to clarify how the atmospheric content of N2O is controlled. We review available data on the various reservoirs of fixed nitrogen, the transfer rates between the reservoirs, and estimate how the reservoir contents and transfer rates can change under man's influence. It is seen that sources, sinks and lifetime of atmospheric N2O are not understood well. Based on our limited knowledge of the stability of atmospheric N2O we conclude that future growth in the usage of industrial fixed nitrogen fertilizers could cause a 1% to 2% global ozone reduction in the next 50 years. However, centuries from now the ozone layer could be reduced by as much as 10% if soils are the major source of atmospheric N2O.

  16. 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

  17. 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

  18. Suppression of antibody response in mice by acute exposure to nitrogen dioxide: in vitro study

    SciTech Connect

    Hidekazu, F.; Shimizu, F.; Kubota, K.

    1981-12-01

    The effect of acute exposure to nitrogen dioxide (NO/sub 2/) on in vitro primary and secondary antibody responses to sheep red blood cells (SRBC) was studied in BALB/c mice. After the in vivo exposure to 20 ppm NO/sub 2/ for 12 hr, spleen cells were separated and then cultured with SRBC. Cell reconstitution experiments indicated that in the primary antibody response B cells were more strongly suppressed than T cells, while in the secondary response suppression of primed T cells was greater than that of prime B cells.

  19. 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.

  20. Pulmonary function in normal and elastase-treated hamsters exposed to a complex mixture of olefin-ozone-sulfur dioxide reaction products

    SciTech Connect

    Raub, J.A.; Miller, F.J.; Graham, J.A.; Gardner, D.E.; O'Neil, J.J.

    1983-01-01

    An elastase-induced emphysema model was utilized to determine if hamsters with preexisting lung disease were more susceptible to lung damage from air-pollutant exposure. Male golden hamsters, divided into two treatment groups, were given a single intratracheal injection of either 6 units of porcine pancreatic elastase (EMP) or buffer (CNT). After a 4-week recovery period, equal numbers of each group were exposed 23 hr/day x 28 day to filtered air (AIR) or to the complex by-products from a dark-phase-reaction mixture of trans-2-butene, ozone, and sulfur dioxide (MIX). Lung-function measurements on the elastase-treated groups showed changes consistent with mild emphysema. There were no significant differences in lung volumes or lung compliance between the AIR- and MIX-exposed animals. However, the nitrogen washout slope decreased and the diffusing capacity for carbon monoxide increased in both the CNT and EMP hamsters exposed to the MIX. The change in diffusing capacity was greater in normal hamsters than in hamsters with emphysema, and it is hypothesized that animals with impaired lung function had a decreased ability to respond to a pulmonary insult from the mix.

  1. Effects of ozone and sulfur dioxide on processing tomato yields and quality. Final report

    SciTech Connect

    Brewer, R.F.

    1986-03-01

    The object of the experiment was to study the effects of SO/sub 2/ and/or ozone on tomato vegetative growth, fruit yields, and fruit quality. Two varieties of processing tomatoes, UC-204-B and E-6203, were exposed to four levels of ozone and two levels of SO/sub 2/. Exposure to ambient ozone caused a 20% reduction in vine weights and 27% reduction in weight of red fruit compared to filtered air. Exposure to 0.1 ppm SO/sub 2/ produced 7% fewer vines and approximately 8% less fruit as compared with no SO/sub 2/ exposure. Fruit quality tests indicated that increasing ozone levels reduce soluble solids (Brix), and they reduce viscosity, an important indicator of processing behavior. Exposure to SO/sub 2/ in the concentrations used increased total solids but had no measurable effect on viscosity or consistency.

  2. The chronic response of yellow-poplar and eastern white pine to ozone and elevated carbon dioxide: three-year summary

    Treesearch

    Joanne Rebbeck

    1996-01-01

    The objective of this study was to determine the long-term effects of ozone (O3) and carbon dioxide (CO2) on the growth and physiology of eastern white pine (Pinus strobus) and yellow-poplar (Liriodendron tulipifera) under plantation conditions. Two separate plantations of each species...

  3. Chemical composition and digestibility of Trifolium exposed to elevated ozone and carbon dioxide in a free-air (FACE) fumigation system

    Treesearch

    R.B. Muntifering; A.H. Chappelka; J.C. Lin; D.F. Karnosky; G.L. Somers

    2006-01-01

    Tropospheric ozone (O3) and carbon dioxide (CO2) are significant drivers of plant growth and chemical composition. We hypothesized that exposure to elevated concentrations of O3 and CO2, singly and in combination, would modify the chemical composition of Trifolium...

  4. Stem wood properties of Populus tremuloides, Betula papyrifera and Acer saccharum saplings after three years of treatments to elevated carbon dioxide and ozone

    Treesearch

    Seija Kaakinen; Katri Kostiainen; Fredrik Ek; Pekka Saranpaa; Mark E. Kubiske; Jaak Sober; David F. Karnosky; Elina Vapaavuori

    2004-01-01

    The aim of this study was to examine the effects of elevated carbon dioxide [CO2] and ozone [O3] and their interaction on wood chemistry and anatomy of five clones of 3-year-old trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera...

  5. Influences of rising atmospheric carbon dioxide and ozone concentrations on growth, yield and soil C dynamics in a soybean-wheat no-till system.

    USDA-ARS?s Scientific Manuscript database

    Elevated atmospheric carbon dioxide and ozone concentrations often have counteracting influences on many C3 crops depending on the concentration and sensitivity of the crop to the gases. Effects of the gas treatments on plant growth likely extend to soil microbial and decomposition processes, altho...

  6. Sequential disinfection of E. coli O157:H7 on shredded lettuce leaves by aqueous chlorine dioxide, ozonated water, and thyme essential oil

    NASA Astrophysics Data System (ADS)

    Singh, Nepal; Singh, Rakesh K.; Bhunia, Arun K.; Stroshine, Richard L.; Simon, James E.

    2001-03-01

    There have been numerous studies on effectiveness of different sanitizers for microbial inactivation. However, results obtained from different studies indicate that microorganism cannot be easily removed from fresh cut vegetables because of puncture and cut surfaces with varying surface topographies. In this study, three step disinfection approach was evaluated for inactivation of E. coli O157:H7 on shredded lettuce leaves. Sequential application of thyme oil, ozonated water, and aqueous chlorine dioxide was evaluated in which thyme oil was applied first followed by ozonated water and aqueous chlorine dioxide. Shredded lettuce leaves inoculated with cocktail culture of E. coli O157:H7 (C7927, EDL 933 and 204 P), were washed with ozonated water (15 mg/l for 10min), aqueous chlorine dioxide (10 mg/l,for 10min) and thyme oil suspension (0.1%, v/v for 5min). Washing of lettuce leaves with ozonated water, chlorine dioxide and thyme oil suspension resulted in 0.44, 1.20, and 1.46 log reduction (log10 cfu/g), respectively. However, the sequential treatment achieved approximately 3.13 log reductions (log10 cfu/g). These results demonstrate the efficacy of sequential treatments in decontaminating shredded lettuce leaves containing E. coli O157:H7.

  7. Influences of elevated carbon dioxide and ozone on soil respiration and carbon accumulation in a no-till soybean-wheat system after six years

    USDA-ARS?s Scientific Manuscript database

    Atmospheric carbon dioxide and ozone often have counteracting influences on many C3 crops depending on the concentration of the gases and sensitivity of the crop and variety, but effects of these gases on plant-soil processes are poorly understood. The objective of this six-year experiment was to d...

  8. 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.

  9. Air-snow exchange of nitrogen oxides and ozone at a polluted mid-latitude site

    NASA Astrophysics Data System (ADS)

    Murphy, Jennifer G.; Hong, Angela C.; Quinn, Patricia K.; Bates, Tim

    2017-04-01

    Vertical gradients of O3, NO, NO2 and NOywere measured within and above the snowpack between January 17 to February 14, 2014 as part of the Uintah Basin Winter Ozone Study. During the first half of the campaign, the snowpack was relatively aged and contained high levels of inorganic ions and dissolved and particulate organics. A snowfall on Jan 31 added 5 cm of fresh snow with lower solute concentrations to the top of the snowpack. Vertical gradients (ΔC = C(25cm) - C(125cm)) in the measured gas phase species were used to investigate the role of the snowpack as a source or sink. Small positive gradients were seen for NO, peaking in the middle of the day, which much larger negative gradients were seen for O3 and NOy. Comparing the fresh to the aged snowpacks, there was a noticeable decrease in the gradient for O3, but not for NOy over the fresh snow, implying a chemical control of O3 deposition to the snow. The ratio of the gradient of NOx to the gradient of NOy was used to determine a snowpack NOy recycling ratio (emission/deposition) of approximately 4 %, consistent with independent estimates of low nitrate photolysis rates inferred from nitrogen isotopes by Zatko et al., (2016). Reference Zatko et al., The magnitude of the snow-sourced reactive nitrogen flux to the boundary layer in the Uintah Basin, Utah, USA, Atmos. Chem. Phys., 16, 13837-13851, 2016.

  10. Relationship between lightning activity and tropospheric nitrogen dioxide and the estimation of lightning-produced nitrogen oxides over China

    NASA Astrophysics Data System (ADS)

    Guo, Fengxia; Ju, Xiaoyu; Bao, Min; Lu, Ganyi; Liu, Zupei; Li, Yawen; Mu, Yijun

    2017-02-01

    To better understand the relationship between lightning activity and nitrogen oxides (NO X ) in the troposphere and to estimate lightning-produced NO X (LNO X ) production in China more precisely, spatial and temporal distributions of vertical column densities of tropospheric nitrogen dioxide (NO2 VCDs) and lightning activity were analyzed using satellite measurements. The results showed that the spatial distribution of lightning activity is greater in the east than in the west of China, as with NO2 VCDs. However, the seasonal and annual variation between lightning and NO2 density show different trends in the east and west. The central Tibetan Plateau is sparsely populated without modern industry, and NO2 VCDs across the plateau are barely affected by anthropogenic sources. The plateau is an ideal area to study LNO X . By analyzing 15 years of satellite data from that region, it was found that lightning density is in strong agreement with annual, spatial and seasonal variations of NO2 VCDs, with a correlation coefficient of 0.79 from the linear fit. Combining Beirle's method and the linear fit equation, LNO X production in the Chinese interior was determined to be 0.07 (0.02-0.27) TgN yr-1 for 1997-2012, within the range of 0.016-0.384 TgN yr-1 from previous estimates.

  11. Chemical Loss of Ozone in the Arctic Polar Vortex in the Winter of 1991-1992

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; Gottlieb, E. W.; Lait, L. R.; Newman, P. A.; Schoeberl, M. R.; Strahan, S. E.; Loewenstein, M.; Podolske, J. R.; Chan, K. R.; hide

    1993-01-01

    In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

  12. Chemical loss of ozone in the Arctic polar vortex in the winter of 1991- 1992

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Wofsy, S. C.; Gottlieb, E. W.; Lait, L. R.; Newman, P. A.; Schoeberl, M. R.; Loewenstein, M.; Podolske, J. R.; Strahan, S. E.; Proffitt, M. H.

    1993-01-01

    In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

  13. Inter-comparison of nitrogen dioxide column densities retrieved by ground-based MAX-DOAS and Pandora, and space borne OMI measurements over Seoul

    NASA Astrophysics Data System (ADS)

    Yun, S.; Lee, H.; Kim, J.; Jeong, U.; Herman, J. R.

    2013-12-01

    It is important to understand spatial and temporal characteristics of nitrogen dioxide (NO2) which affects atmospheric chemistry with respect to aerosol and ozone formation. In this present study, we used Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and Pandora to investigate vertical information of NO2. The measurements took place from August to October in 2013 in Seoul, one of the largest megacities in Northeast Asia. Slant column densities (SCDs) of NO2 at each elevation angle (EA) were derived using the MAX-DOAS technique that utilizes scattered sunlight at multiple EAs as a light source. Vertical distributions of tropospheric NO2 were retrieved utilizing measured SCDs and those simulated with Trace gas RAdiative Transfer Monte Carlo Y(I)mplementation (TRACY) with inputs of aerosol optical properties from sunphotometer and Micro Pulse LIDAR (MPL) measurements. On the other hand, Pandora, which uses direct sunlight as a light source, was used to obtain total NO2 column densities for the same measurement period. Tropospheric and total NO2 column densities retrieved using those two ground based instruments were compared with those obtained from Ozone Monitoring Instrument (OMI) data.

  14. [Change in genotoxicity of wastewater during chlorine dioxide and ahlorine disinfections and the influence of ammonia nitrogen].

    PubMed

    Wang, Li-Sha; Hu, Hong-Ying; Ta, Chun-Hong; Tian, Jie; Wang, Chao; Koichi, Fujie

    2007-03-01

    The effects of chlorine dioxide and chlorine disinfections on genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test. The experiment results showed that when chlorine dioxide dosage increased from 0 mg/L to 30 mg/L, the genotoxicity of wastewater first decreased rapidly and then tended to be stable, while when the chlorine dosage increased from 0 mg/L to 30 mg/L, the genotoxicity of wastewater changed diversely for different samples. It was then found that ammonia nitrogen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater, while it greatly affected the change of genotoxicity during chlorine disinfection of wastewater. When the concentration of ammonia nitrogen was low (< 10 - 20 mg/L), the genotoxicity of wastewater decreased after chlorine disinfection, and when the concentration of ammonia nitrogen was high (> 10 - 20 mg/L), the genotoxicity of wastewater increased after chlorine disinfection.

  15. Nitrogen dioxide radicals mediated mineralization of perfluorooctanoic acid in aqueous nitrate solution with UV irradiation.

    PubMed

    Li, Aimin; Zhang, Zhe; Li, Peifeng; Cai, Lejuan; Zhang, Lizhi; Gong, Jingming

    2017-09-03

    Effective decomposition of perfluorooctanoic acid (PFOA) has received increasing attention in recent years because of its global occurrence and resistance to most conventional treatment processes. In this study, the complete mineralization of PFOA was achieved by the UV-photolysis of nitrate aqueous solution (UV/Nitrate), where the in-situ generated nitrogen dioxide radicals (NO2) efficiently mediated the degradation of PFOA. In particular, when the twinborn hydroxyl radicals were scavenged, the production of more NO2 radicals realized the complete mineralization of PFOA. DFT calculations further confirm the feasibility of PFOA removal with NO2. Near-stoichiometric equivalents of fluoride released rather than the related intermediates were detected in solution after decomposition of PEOA, further demonstrating the complete degradation of PFOA. Possible PFOA degradation pathways were proposed on the basis of experimental results. This work offers an efficient strategy for the complete mineralization of perfluorinated chemicals, and also sheds light on the indispensable roles of nitrogen dioxide radicals for environmental pollutants removal. Copyright © 2017. Published by Elsevier Ltd.

  16. Passive dosimeters for nitrogen dioxide in personal/indoor air sampling: A review

    PubMed Central

    Yu, Chang Ho; Morandi, Maria T.; Weisel, Clifford P.

    2015-01-01

    Accurate measurement of nitrogen dioxide concentrations in both outdoor and indoor environments, including personal exposures, is a fundamental step for linking atmospheric nitrogen dioxide levels to potential health and ecological effects. The measurement has been conducted generally in two ways: active (pumped) sampling and passive (diffusive) sampling. Diffusion samplers, initially developed and used for workplace air monitoring, have been found to be useful and cost-effective alternatives to conventional pumped samplers for monitoring ambient, indoor and personal exposures at the lower concentrations found in environmental settings. Since the 1970s, passive samplers have been deployed for ambient air monitoring in urban and rural sites, and to determine personal and indoor exposure to NO2. This article reviews the development of NO2 passive samplers, the sampling characteristics of passive samplers currently available, and their application in ambient and indoor air monitoring and personal exposure studies. The limitations and advantages of the various passive sampler geometries (i.e., tube, badge, and radial type) are also discussed. This review provides researchers and risk assessors with practical information about NO2 passive samplers, especially useful when designing field sampling strategies for exposure and indoor/outdoor air sampling. PMID:18446185

  17. 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.

  18. Passive monitoring of nitrogen dioxide in urban air: a case study of Durban metropolis, South Africa.

    PubMed

    Moodley, Kandasamy G; Singh, Shalini; Govender, Suendran

    2011-09-01

    To devise and implement strategies to manage the quality of urban air, a metropolis needs air pollution data on which an air quality management plan can be formulated. Although air pollutants can come from several sources, many reports suggest that nitrogen dioxide from motor vehicle emissions is the major contributor to air pollution in cities. Since vehicles stop or move slowly through traffic intersections, concentrations of nitrogen dioxide (NO(2)) are expected to be relatively high at these sites. Inexpensive Ogawa passive samplers were placed at selected traffic intersections in the Durban Metropolis to trap the NO(2) which was then analysed by a sensitive laboratory-based method. The data obtained by this method was compared with data from sophisticated system comprising an active sampler cum on-line chemiluminescence detector. The sampling was done over a twelve month period to cover all seasons. Statistical analysis of the data showed that there was no significant difference between the means for the two methods. This study has established that an Ogawa passive sampler may be used as an economical and reliable collector for NO(2) in ambient air under varying climatic conditions. Further, the analysis method using a UV-Visible spectrophotometer was sensitive enough to detect NO(2) at the 10-20 ppb level. The cost of the method should be well within the budgets of most municipalities and it would motivate them to develop policies to alleviate traffic congestion. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Exposure to carbon monoxide and nitrogen dioxide in enclosed ice arenas.

    PubMed

    Pelham, T W; Holt, L E; Moss, M A

    2002-04-01

    This article summarises the latest information on the adverse cardiorespiratory effects of exposure to carbon monoxide (CO) and nitrogen dioxide (NO(2)) in enclosed ice rinks. Sources of CO and NO(2) emissions are identified, current standards for these agents, as well as methods of controlling the emissions, dispersion, and evacuation of these toxic gases are presented. A detailed literature search involving 72 references in English and French from research conducted in North America and Europe was used. Material was from peer reviewed journals and other appropriate sources. Air pollutants such as carbon monoxide (CO), and nitrogen dioxide (NO(2)) which are present in enclosed skating facilities, may exacerbate a pre-existing pathogenic condition in those people who spend considerable time in these environments. Considering the popularity of ice hockey, short track speed skating, and figure skating, and the hundreds of hours that a sensitive person may spend each year in these environments, it would seem appropriate to seek more definitive answers to this important health problem. From the findings and conclusions of the research reviewed in this paper, 10 recommendations are listed.

  20. 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.

  1. Earth's Endangered Ozone

    ERIC Educational Resources Information Center

    Panofsky, Hans A.

    1978-01-01

    Included are (1) a discussion of ozone chemistry; (2) the effects of nitrogen fertilizers, fluorocarbons, and high level aircraft on the ozone layer; and (3) the possible results of a decreasing ozone layer. (MR)

  2. Earth's Endangered Ozone

    ERIC Educational Resources Information Center

    Panofsky, Hans A.

    1978-01-01

    Included are (1) a discussion of ozone chemistry; (2) the effects of nitrogen fertilizers, fluorocarbons, and high level aircraft on the ozone layer; and (3) the possible results of a decreasing ozone layer. (MR)

  3. Atmospheric oxidants. [ozone concentration and combustion product aspects in spacecraft design

    NASA Technical Reports Server (NTRS)

    Daniels, G. E.

    1973-01-01

    The ingredients which cause the air pollution are a mixture of oxides of organic matter (mostly nitrogen oxides and hydrocarbons) and ozone. Ozone, although considered one of the rare atmospheric gases, needs consideration in spacecraft design because of its chemical reaction (oxidation) with organic materials, especially rubber, which becomes hard and brittle under tension in a few minutes time. At the earth surface, a maximum of 60 parts per hundred million of oxidants composed of nitrogen oxides, hydrocarbons, sulphur dioxide, sulphur trioxides, peroxides, and ozone can be expected for 72 hours when smog occurs. A table representing distribution of ozone concentration with atmospheric altitude is included.

  4. OBSERVATION-BASED ASSESSMENT OF THE IMPACT OF NITROGEN OXIDES EMISSIONS REDUCTIONS ON OZONE AIR QUALITY OVER THE EASTERN UNITED STATES

    EPA Science Inventory

    Ozone is produced by chemical interactions involving nitrogen oxides (NOx) and Volatile Organic Compounds (VOCs) in the presence of sunlight. At high concentrations, ground-level ozone has been shown to be harmful to human health and the environment. It has been reco...

  5. OBSERVATION-BASED ASSESSMENT OF THE IMPACT OF NITROGEN OXIDES EMISSIONS REDUCTIONS ON OZONE AIR QUALITY OVER THE EASTERN UNITED STATES

    EPA Science Inventory

    Ozone is produced by chemical interactions involving nitrogen oxides (NOx) and Volatile Organic Compounds (VOCs) in the presence of sunlight. At high concentrations, ground-level ozone has been shown to be harmful to human health and the environment. It has been reco...

  6. Modeling the intraurban variation in nitrogen dioxide in urban areas in Kathmandu Valley, Nepal.

    PubMed

    Gurung, Anobha; Levy, Jonathan I; Bell, Michelle L

    2017-05-01

    With growing urbanization, traffic has become one of the main sources of air pollution in Nepal. Understanding the impact of air pollution on health requires estimation of exposure. Land use regression (LUR) modeling is widely used to investigate intraurban variation in air pollution for Western cities, but LUR models are relatively scarce in developing countries. In this study, we developed LUR models to characterize intraurban variation of nitrogen dioxide (NO2) in urban areas of Kathmandu Valley, Nepal, one of the fastest urbanizing areas in South Asia. Over the study area, 135 monitoring sites were selected using stratified random sampling based on building density and road density along with purposeful sampling. In 2014, four sampling campaigns were performed, one per season, for two weeks each. NO2 was measured using duplicate Palmes tubes at 135 sites, with additional information on nitric oxide (NO), NO2, and nitrogen oxide (NOx) concentrations derived from Ogawa badges at 28 sites. Geographical variables (e.g., road network, land use, built area) were used as predictor variables in LUR modeling, considering buffers 25-400m around each monitoring site. Annual average NO2 by site ranged from 5.7 to 120ppb for the study area, with higher concentrations in the Village Development Committees (VDCs) of Kathmandu and Lalitpur than in Kirtipur, Thimi, and Bhaktapur, and with variability present within each VDC. In the final LUR model, length of major road, built area, and industrial area were positively associated with NO2 concentration while normalized difference vegetation index (NDVI) was negatively associated with NO2 concentration (R(2)=0.51). Cross-validation of the results confirmed the reliability of the model. The combination of passive NO2 sampling and LUR modeling techniques allowed for characterization of nitrogen dioxide patterns in a developing country setting, demonstrating spatial variability and high pollution levels. Copyright © 2017 Elsevier

  7. 76 FR 68638 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Revision to Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... Nitrogen Oxides Budget Trading Program AGENCY: Environmental Protection Agency (EPA). ACTION: Direct final... Implementation Plan (SIP). The revision pertains to regulatory language in its nitrogen oxides (NO X ) Budget..., Nitrogen dioxide, Ozone, Sulfur oxides. Dated: October 25, 2011. W.C. Early, Acting Regional...

  8. Effects of ozone exposure on 'Golden' papaya fruit by photoacoustic phase-resolved method: Physiological changes associated with carbon dioxide and ethylene emission rates during ripening

    SciTech Connect

    Correa, Savio Figueira; Brito Paiva, Luisa; Mota do Couto, Flavio; Gomes da Silva, Marcelo; Silva Sthel, Marcelo; Vargas, Helion; Mota, Leonardo; Goncalves de Oliveira, Jurandi; Miklos, Andras

    2011-06-01

    This work addresses the effects of ozone activity on the physiology of 'Golden' papaya fruit. Depth profile analysis of double-layer biological samples was accomplished using the phase-resolved photoacoustic spectroscopy. The feasibility of the method was demonstrated by singling out the spectra of the cuticle and the pigment layers of papaya fruit. The same approach was used to monitor changes occurring on the fruit during ripening when exposed to ozone. In addition, one has performed real time studies of fluorescence parameters and the emission rates of carbon dioxide and ethylene. Finally, the amount of pigments and the changes in waxy cuticle have been monitored. Results indicate that a fruit deliberately subjected to ozone at a level of 6 ppmv underwent ripening sooner (at least 24-48 h) than a fruit stored at ambient conditions. Moreover, ozone caused a reduction in the maximum quantum yield of photosynthetic apparatus located within the skin of papaya fruit.

  9. Effects of ozone exposure on `Golden' papaya fruit by photoacoustic phase-resolved method: Physiological changes associated with carbon dioxide and ethylene emission rates during ripening

    NASA Astrophysics Data System (ADS)

    Corrêa, Savio Figueira; Mota, Leonardo; Paiva, Luisa Brito; Couto, Flávio Mota do; Silva, Marcelo Gomes da; Oliveira, Jurandi Gonçalves de; Sthel, Marcelo Silva; Vargas, Helion; Miklós, András

    2011-06-01

    This work addresses the effects of ozone activity on the physiology of `Golden' papaya fruit. Depth profile analysis of double-layer biological samples was accomplished using the phase-resolved photoacoustic spectroscopy. The feasibility of the method was demonstrated by singling out the spectra of the cuticle and the pigment layers of papaya fruit. The same approach was used to monitor changes occurring on the fruit during ripening when exposed to ozone. In addition, one has performed real time studies of fluorescence parameters and the emission rates of carbon dioxide and ethylene. Finally, the amount of pigments and the changes in waxy cuticle have been monitored. Results indicate that a fruit deliberately subjected to ozone at a level of 6 ppmv underwent ripening sooner (at least 24-48 h) than a fruit stored at ambient conditions. Moreover, ozone caused a reduction in the maximum quantum yield of photosynthetic apparatus located within the skin of papaya fruit.

  10. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  11. Insights into the Electronic Structure of Ozone and Sulfur Dioxide from Generalized Valence Bond Theory: Addition of Hydrogen Atoms.

    PubMed

    Lindquist, Beth A; Takeshita, Tyler Y; Dunning, Thom H

    2016-05-05

    Ozone (O3) and sulfur dioxide (SO2) are valence isoelectronic species, yet their properties and reactivities differ dramatically. In particular, O3 is highly reactive, whereas SO2 is chemically relatively stable. In this paper, we investigate serial addition of hydrogen atoms to both the terminal atoms of O3 and SO2 and to the central atom of these species. It is well-known that the terminal atoms of O3 are much more amenable to bond formation than those of SO2. We show that the differences in the electronic structure of the π systems in the parent triatomic species account for the differences in the addition of hydrogen atoms to the terminal atoms of O3 and SO2. Further, we find that the π system in SO2, which is a recoupled pair bond dyad, facilitates the addition of hydrogen atoms to the sulfur atom, resulting in stable HSO2 and H2SO2 species.

  12. Regulatory Effects of Elevated Carbon Dioxide on Growth and Biochemical Responses to Ozone Stress in Chinese Pine (Pinus tabulaeformis Carr.).

    PubMed

    Liu, Zhouli; Chen, Wei; He, Xingyuan; Fu, Shilei; Lu, Tao

    2016-12-01

    This study examined whether carbon dioxide (CO2) might alleviate ozone (O3) injury to the dominant coniferous forest species of northern China, Pinus tabulaeformis Carr. After 90 days O3 exposure, biomass and net photosynthetic rate (Pn) decreased significantly by 24.44 % and 42.89 % compared with the control. A significant increase in malondialdehyde (MDA) was shown, suggesting cell membrane damage and oxidative stress. However, the positive responses of biomass dry weight, antioxidative enzymes and soluble sugar contents under elevated CO2 alone and the combination of elevated CO2 and O3 were observed, indicating that CO2 could ameliorate O3-induced injury. The study provided increasing evidence that moderately elevated CO2 levels may have a beneficial effect on the forest ecosystem to respond to global climate change.

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

    NASA Astrophysics Data System (ADS)

    Tavares, C. J.; Marques, S. M.; Viseu, T.; Teixeira, V.; Carneiro, J. O.; Alves, E.; Barradas, N. P.; Munnik, F.; Girardeau, T.; Rivière, 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 N2:O2 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 °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 visible light.

  14. 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

  15. On the interaction of isotopic exchange processes with photochemical reactions in atmospheric oxides of nitrogen

    SciTech Connect

    Freyer, H.D.; Kley, D.; Volz-Thomas, A.; Kobel, K.

    1993-08-20

    The authors study the isotopic composition of nitic oxide and nitrogen dioxide in the atmosphere. They model the observed results for {sup 15}N/{sup 14}N ratios in terms of isotopic exchange reactions with ozone and photolytic reactions on the oxides. They find there has to be an interaction of these two reactions, in conjunction with seasonl variations of nitrogen oxide/ozone ratios, to account for observed isotopic ratios of the nitrogen isotopes.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: effects on its optical and antioxidant properties.

    PubMed

    Wenk, Jannis; Aeschbacher, Michael; Salhi, Elisabeth; Canonica, Silvio; von Gunten, Urs; Sander, Michael

    2013-10-01

    In water treatment dissolved organic matter (DOM) is typically the major sink for chemical oxidants. The resulting changes in DOM, such as its optical properties have been measured to follow the oxidation processes. However, such measurements contain only limited information on the changes in the oxidation states of and the reactive moieties in the DOM. In this study, we used mediated electrochemical oxidation to quantify changes in the electron donating capacities (EDCs), and hence the redox states, of three different types of DOM during oxidation with chlorine dioxide (ClO2), chlorine (as HOCl/OCl(-)), and ozone (O3). Treatment with ClO2 and HOCl resulted in comparable and prominent decreases in EDCs, while the UV light absorbances of the DOM decreased only slightly. Conversely, ozonation resulted in only small decreases of the EDCs but pronounced absorbance losses of the DOM. These results suggest that ClO2 and HOCl primarily reacted as oxidants by accepting electrons from electron-rich phenolic and hydroquinone moieties in the DOM, while O3 reacted via electrophilic addition to aromatic moieties, followed by ring cleavage. This study highlights the potential of combined EDC-UV measurements to monitor chemical oxidation of DOM, to assess the nature of the reactive moieties and to study the underlying reaction pathways.

  1. Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation.

    PubMed Central

    Zoeteman, B C; Hrubec, J; de Greef, E; Kool, H J

    1982-01-01

    A retrospective epidemiological study in The Netherlands showed a statistical association between chlorination by-products in drinking water and cancer of the esophagus and stomach for males. A pilot-plant study with alternative disinfectants was carried out with stored water of the Rivers Rhine and Meuse. It was demonstrated that the increase of direct acting mutagens after treatment with chlorine dioxide is similar to the effect of chlorination. Ozonation of Rhine water reduced the mutagenic activity for Salmonella typhimurium TA 98 both with and without metabolic activation. UV alone hardly affects the mutagenicity of the stored river water for S. typh. TA 98. In all studies, practically no mutagenic activity for S. typh. TA 100 was found. Although remarkable changes in the concentration of individual organic compounds are reported, the identity of the mutagens detected is yet unclear. Compounds of possible interest due to their removal by ozonation are 1,3,3-trimethyloxindole, dicyclopentadiene and several alkylquinolines. Compounds which might be responsible for the increased mutagenicity after chlorination are two brominated acetonitriles and tri(2-chlorethyl) phosphate. Furthermore, the concentration procedure with adsorption on XAD resin and the subsequent elution step may have affected the results. It is proposed to focus further research more on the less volatile by-products of disinfection than on the trihalomethanes. PMID:7151762

  2. Day-of-week Effects in Ozone, Nitrogen Oxides, and VOC Reactivity Within and Downwind of Sacramento

    NASA Astrophysics Data System (ADS)

    Murphy, J. G.; Day, D. A.; Cleary, P. A.; Wooldridge, P. J.; Millet, D. B.; Goldstein, A. H.; Cohen, R. C.

    2007-12-01

    Day-of-week patterns in human activities can be used to examine the ways in which differences in primary emissions result in changes in the rates of photochemical reactions, and the production of secondary pollutants. Data from twelve California Air Resources Board monitoring sites in Sacramento, CA, and the downwind Mountain Counties air basin are analyzed to reveal day of week patterns in ozone and its precursors in the summers of 1998-2002. On the weekends, NOx concentrations drop by 35%, whereas VOC reactivity changes by less than 15%, likely due to significant reductions in diesel truck traffic. The main driver for day-of- week differences in ozone abundance at urban sites is the reduced titration of O3 by fresh NO emissions on weekends. By analyzing day-of-week patterns in odd oxygen (O3+NO2), we can eliminate this complication and focus on the NOx-dependence of ozone production and the related photochemistry. In the downwind Mountain Counties, ozone production is found to be NOx-limited, whereas at the urban and suburban sites of Sacramento, ozone production is NOx-saturated. An analysis of day-of-week cycles in Sacramento reveals that boundary layer chemistry and mixing in of residual air from above both contribute to the observed accumulation of ozone at surface sites. This interpretation is consistent with the day-of-week patterns in a range of VOC with different emission sources and lifetimes and in higher nitrogen oxides that are co-products of ozone. We use isoprene as a probe of local oxidation rates, and infer that on the weekend OH is higher in the urban area and lower at one of the forested Mountain Counties sites, as expected from the NOx- dependence. Our analysis also demonstrates that in NOx-saturated environments, gas phase HNO3, and by extension particulate nitrate, concentrations are relatively insensitive to changes in NOx emissions.

  3. Growth and crown architecture of two aspen genotypes exposed to interacting ozone and carbon dioxide

    Treesearch

    Richard E. Dickson; M.D. Coleman; Priit Pechter; David Karnosky

    2001-01-01

    To study the impact of ozone (O3) and O3 plus CO2 on aspen growth, we planted two trembling aspen clones, differing in sensitivity to O3, in the ground in open-top chambers and exposed them to different concentrations of O3 and O3 plus CO2...

  4. Growth and crown architecture of two aspen genotypes exposed to interacting ozone and carbon dioxide.

    PubMed

    Dickson, R E; Coleman, M D; Pechter, P; Karnosky, D

    2001-01-01

    To study the impact of ozone (O3) and O3 plus CO2 on aspen growth, we planted two trembling aspen clones, differing in sensitivity to O3 in the ground in open-top chambers and exposed them to different concentrations of O3 and O3 plus CO, for 98 days. Ozone exposure (58 to 97 microl l(-1)-h. total exposure) decreased growth and modified crown architecture of both aspen clones. Ozone exposure decreased leaf, stem, branch, and root dry weight particularly in the O3 sensitive clone (clone 259). The addition of CO2 (150 microl l(-1) over ambient) to the O3 exposure counteracted the negative impact of O3 only in the O3 tolerant clone (clone 216). Ozone had relatively little effect on allometric ratios such as, shoot/root ratio, leaf weight ratio, or root weight ratio. In both clones, however, O3 decreased the shoot dry weight, shoot length ratio and shoot diameter. This decrease in wood strength caused both current terminals and long shoots to droop and increased the branch angle of termination. These results show that aspen growth is highly sensitive to O3 and that O3 can also significantly affect crown architecture. Aspen plants with drooping terminals and lateral branches would be at a competitive disadvantage in dense stands with limited light.

  5. 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

  6. The application of artificial neural networks for discrete wavelength retrievals of atmospheric nitrogen dioxide from space

    NASA Astrophysics Data System (ADS)

    Lawrence, J.; Singh Anand, J.; Leigh, R.; Chang, M.; Monks, P. S.

    2012-12-01

    Despite emission reductions in Europe, air quality continues to be a major health and policy issue. Significant areas of uncertainty persist in relating emissions, atmospheric composition and human exposure within the urban atmosphere. Furthermore, air quality continues to worsen in some highly populated parts of the world. The current air quality monitoring framework is based upon bottom-up emission estimates coupled with sparse in situ monitoring. Research at the University of Leicester in the UK is being conducted to investigate the feasibility of using a technique of discrete wavelength sunlight spectroscopy to derive concentrations of the pollutant nitrogen dioxide from a satellite platform. This technique has the potential to enable very light and compact instrumentation and may subsequently provide abundant air quality data of significant value to users and policy makers. A back propagation multi-layered perceptron artificial neural network (ANN) has been developed to retrieve atmospheric slant columns of nitrogen dioxide from simulated measurements. The ANN approach enables retrievals to be performed much faster than other retrieval methods once the network has been appropriately trained, which is a particularly useful feature in instances where a large quantity of retrievals is required in near real time. To generate the required training data for the ANN to understand the necessary relationships a radiative transfer model SCIATRAN was run to provide millions of spectral intensities and slant column concentrations. To enable the radiative transfer simulations to realistically portray urban air quality the SCIATRAN model was fed atmospheric profile and aerosol data from modelled air quality forecasts over London to enable assimilation of the atmospheric composition of a typical urban environment. The training data produced by SCIATRAN was configured to span a range of solar azimuth and zenith angles to provide results which are applicable to all low earth

  7. The Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI): design, execution, and early results

    NASA Astrophysics Data System (ADS)

    Piters, A. J. M.; Boersma, K. F.; Kroon, M.; Hains, J. C.; van Roozendael, M.; 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.; Clémer, K.; Fayt, C.; Frieß, U.; Gast, L. F. L.; Gil-Ojeda, M.; Goutail, F.; Graves, R.; Griesfeller, A.; Großmann, K.; Hemerijckx, G.; Hendrick, F.; Henzing, B.; Herman, J.; Hermans, C.; Hoexum, M.; van der Hoff, G. R.; Irie, H.; Johnston, P. V.; Kanaya, Y.; Kim, Y. J.; Klein Baltink, H.; Kreher, K.; de Leeuw, G.; Leigh, R.; Merlaud, A.; Moerman, M. M.; Monks, P. S.; Mount, G. H.; Navarro-Comas, M.; Oetjen, H.; Pazmino, A.; Perez-Camacho, M.; Peters, E.; Du Piesanie, A.; Pinardi, G.; Puentedura, O.; Richter, A.; Roscoe, H. K.; Schönhardt, A.; Schwarzenbach, B.; Shaiganfar, R.; Sluis, W.; Spinei, E.; Stolk, A. P.; Strong, K.; Swart, D. P. J.; Takashima, H.; Vlemmix, T.; Vrekoussis, M.; Wagner, T.; Whyte, C.; Wilson, K. M.; Yela, M.; Yilmaz, S.; Zieger, P.; Zhou, Y.

    2012-02-01

    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-of-the-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

  8. The Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI): design, execution, and early results

    NASA Astrophysics Data System (ADS)

    Piters, A. J. M.; Boersma, K. F.; Kroon, M.; Hains, J. C.; van Roozendael, M.; Wittrock, F.; Abuhassan, N.; Adams, C.; Akrami, M.; Allaart, M. A. F.; Apituley, A.; Bergwerff, J. B.; Berkhout, A. J. C.; Brunner, D.; Cede, A.; Chong, J.; Clémer, K.; Fayt, C.; Frieß, U.; Gast, L. F. L.; Gil-Ojeda, M.; Goutail, F.; Graves, R.; Griesfeller, A.; Großmann, K.; Hemerijckx, G.; Hendrick, F.; Henzing, B.; Herman, J.; Hermans, C.; Hoexum, M.; van der Hoff, G. R.; Irie, H.; Johnston, P. V.; Kanaya, Y.; Kim, Y. J.; Klein Baltink, H.; Kreher, K.; de Leeuw, G.; Leigh, R.; Merlaud, A.; Moerman, M. M.; Monks, P. S.; Mount, G. H.; Navarro-Comas, M.; Oetjen, H.; Pazmino, A.; Perez-Camacho, M.; Peters, E.; Du Piesanie, A.; Pinardi, G.; Puentadura, O.; Richter, A.; Roscoe, H. K.; Schönhardt, A.; Schwarzenbach, B.; Shaiganfar, R.; Sluis, W.; Spinei, E.; Stolk, A. P.; Strong, K.; Swart, D. P. J.; Takashima, H.; Vlemmix, T.; Vrekoussis, M.; Wagner, T.; Whyte, C.; Wilson, K. M.; Yela, M.; Yilmaz, S.; Zieger, P.; Zhou, Y.

    2011-09-01

    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 in the Netherlands. Its main objectives were to determine the accuracy of state-of-the-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 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 Cabauw 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%, and MAX-DOAS aerosol optical thickness agrees within 20

  9. Analyzer for measurement of nitrogen oxide concentration by ozone content reduction in gas using solid state chemiluminescent sensor

    NASA Astrophysics Data System (ADS)

    Chelibanov, V. P.; Ishanin, G. G.; Isaev, L. N.

    2014-05-01

    Role of nitrogen oxide in ambient air is described and analyzed. New method of nitrogen oxide concentration measurement in gas phase is suggested based on ozone concentration measurement with titration by nitrogen oxide. Research of chemiluminescent sensor composition is carried out on experimental stand. The sensor produced on the base of solid state non-activated chemiluminescent composition is applied as ozone sensor. Composition is put on the surface of polymer matrix with developed surface. Sensor compositions includes gallic acid with addition of rodamine-6G. Model of interaction process between sensor composition and ozone has been developed, main products appeared during reaction are identified. The product determining the speed of luminescense appearance is found. This product belongs to quinone class. Then new structure of chemiluminescent composition was suggested, with absence of activation period and with high stability of operation. Experimental model of gas analyzer was constructed and operation algorithm was developed. It was demonstrated that developed NO measuring instrument would be applied for monitoring purposes of ambient air. This work was partially financially supported by Government of Russian Federation, Grant 074-U01

  10. Comparing mass balance and adjoint methods for inverse modeling of nitrogen dioxide columns for global nitrogen oxide emissions

    NASA Astrophysics Data System (ADS)

    Cooper, Matthew; Martin, Randall V.; Padmanabhan, Akhila; Henze, Daven K.

    2017-04-01

    Satellite observations offer information applicable to top-down constraints on emission inventories through inverse modeling. Here we compare two methods of inverse modeling for emissions of nitrogen oxides (NOx) from nitrogen dioxide (NO2) columns using the GEOS-Chem chemical transport model and its adjoint. We treat the adjoint-based 4D-Var modeling approach for estimating top-down emissions as a benchmark against which to evaluate variations on the mass balance method. We use synthetic NO2 columns generated from known NOx emissions to serve as "truth." We find that error in mass balance inversions can be reduced by up to a factor of 2 with an iterative process that uses finite difference calculations of the local sensitivity of NO2 columns to a change in emissions. In a simplified experiment to recover local emission perturbations, horizontal smearing effects due to NOx transport are better resolved by the adjoint approach than by mass balance. For more complex emission changes, or at finer resolution, the iterative finite difference mass balance and adjoint methods produce similar global top-down inventories when inverting hourly synthetic observations, both reducing the a priori error by factors of 3-4. Inversions of simulated satellite observations from low Earth and geostationary orbits also indicate that both the mass balance and adjoint inversions produce similar results, reducing a priori error by a factor of 3. As the iterative finite difference mass balance method provides similar accuracy as the adjoint method, it offers the prospect of accurately estimating top-down NOx emissions using models that do not have an adjoint.

  11. Nitrogen oxides and ozone in Portugal: trends and ozone estimation in an urban and a rural site.

    PubMed

    Fernández-Guisuraga, José Manuel; Castro, Amaya; Alves, Célia; Calvo, Ana; Alonso-Blanco, Elisabeth; Blanco-Alegre, Carlos; Rocha, Alfredo; Fraile, Roberto

    2016-09-01

    This study provides an analysis of the spatial distribution and trends of NO, NO2 and O3 concentrations in Portugal between 1995 and 2010. Furthermore, an estimation model for daily ozone concentrations was developed for an urban and a rural site. NO concentration showed a significant decreasing trend in most urban stations. A decreasing trend in NO2 is only observed in the stations with less influence from emissions of primary NO2. Several stations showed a significant upward trend in O3 as a result of the decrease in the NO/NO2 ratio. In the northern rural region, ozone showed a strong correlation with wind direction, highlighting the importance of long-range transport. In the urban site, most of the variance is explained by the NO2/NOX ratio. The results obtained by the ozone estimation model in the urban site fit 2013 observed data. In the rural site, the estimated ozone during extreme events agrees with observed concentration.

  12. On the export of reactive nitrogen from Asia: NOx partitioning and effects on ozone

    NASA Astrophysics Data System (ADS)

    Bertram, T. H.; Perring, A. E.; Wooldridge, P. J.; Dibb, J.; Avery, M. A.; Cohen, R. C.

    2013-05-01

    The partitioning of reactive nitrogen (NOy was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO2, total peroxy nitrates (ΣPNs), total alkyl and multi-functional nitrates (ΣANs) and nitric acid (HNO3, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NOx production in aged Asian outflow. ΣPNs account for more than 60% of NOy above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NOx, ΣPNs, ΣANs, HNO3 and average wind speed, we calculate the flux of reactive nitrogen through the meridional plane of 150° W (between 20° and 55° N) to be 0.007 ± 0.002 Tg N day-1, which provides an upper limit of 23 ± 6.5% on the transport efficiency of NOy from East Asia. Observations of NOx, and HOx are used to constrain a 0-D photochemical box model for the calculation of net photochemical ozone production or tendency (Δ O3) as a function of aircraft altitude and NOx concentrations. The model analysis indicates that the photochemical environment of the lower troposphere (altitude < 6 km) over the north Pacific is one of net O3 destruction, with an experimentally determined crossover point between net O3 destruction and net O3 production of 60 pptv NOx. Qualitative indicators of integrated net O3 production derived from simultaneous measurements of O3 and light alkanes (Parrish et al., 1992), also indicate that the north Pacific is, on average, a region of net O3 destruction.

  13. Ozone, Carbon monoxide and Nitrogen oxides time series at four Alpine GAW mountain stations in Central Europe

    NASA Astrophysics Data System (ADS)

    Gilge, S.; Plass-Duelmer, C.; Fricke, W.; Kaiser, A.; Ries, L.; Buchmann, B.

    2010-08-01

    Long-term, ground based in-situ observations of Ozone (O3) and its precursor gases Nitrogen dioxide (NO2) and Carbon monoxide (CO) from the four sites Hohenpeissenberg and Zugspitze (D), Sonnblick (A) and Jungfraujoch (CH) are presented for the period 1995-2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA) procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3) or CO standards provided by the Central Calibration Laboratory (CCL) at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC) for CO and O3 (WCC-Empa; CH). Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period 1995-2007, the O3 mixing ratios have slightly increased at three of the four sites. This was observed independent of wind sector and for most seasons, with a tendency to higher positive trends in winter and lower and partly negative trends in summer. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the highest rate of O3 increase was detected in winter and lowest in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti

  14. Ozone, carbon monoxide and nitrogen oxides time series at four alpine GAW mountain stations in central Europe

    NASA Astrophysics Data System (ADS)

    Gilge, S.; Plass-Duelmer, C.; Fricke, W.; Kaiser, A.; Ries, L.; Buchmann, B.; Steinbacher, M.

    2010-12-01

    Long-term, ground based in-situ observations of ozone (O3) and its precursor gases nitrogen dioxide (NO2) and carbon monoxide (CO) from the four sites Hohenpeissenberg and Zugspitze (D), Sonnblick (A) and Jungfraujoch (CH) are presented for the period 1995-2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA) procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3) or CO standards provided by the Central Calibration Laboratory (CCL) at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC) for CO and O3 (WCC-Empa; CH). Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period, 1995-2007, the O3 mixing ratios have slightly increased at three of the four sites independent of wind sector. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the strongest O3 increase was detected in winter and lowest or even decline in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti-correlation with NO2 was found due to reduced O3 values on working days. Trends are discussed with respect to anthropogenic impacts and vertical

  15. 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).

  16. 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...

  17. 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...

  18. Nitrogen dioxide and kerosene-flame soot calibration of photoacoustic instruments for measurement of light absorption by aerosols

    SciTech Connect

    Arnott, W. Patrick; Moosmu''ller, Hans; Walker, John W.

    2000-12-01

    A nitrogen dioxide calibration method is developed to evaluate the theoretical calibration for a photoacoustic instrument used to measure light absorption by atmospheric aerosols at a laser wavelength of 532.0 nm. This method uses high concentrations of nitrogen dioxide so that both a simple extinction and the photoacoustically obtained absorption measurement may be performed simultaneously. Since Rayleigh scattering is much less than absorption for the gas, the agreement between the extinction and absorption coefficients can be used to evaluate the theoretical calibration, so that the laser gas spectra are not needed. Photoacoustic theory is developed to account for strong absorption of the laser beam power in passage through the resonator. Findings are that the photoacoustic absorption based on heat-balance theory for the instrument compares well with absorption inferred from the extinction measurement, and that both are well within values represented by published spectra of nitrogen dioxide. Photodissociation of nitrogen dioxide limits the calibration method to wavelengths longer than 398 nm. Extinction and absorption at 532 and 1047 nm were measured for kerosene-flame soot to evaluate the calibration method, and the single scattering albedo was found to be 0.31 and 0.20 at these wavelengths, respectively.

  19. 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...

  20. 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: (...

  1. 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...

  2. 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

  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. 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.

  5. Spatiotemporal inhomogeneity in nitrogen dioxide (NO2) over Fukuoka observed by Car MAX-DOAS

    NASA Astrophysics Data System (ADS)

    Takashima, H.; Yamaguchi, H.; Maruyama, Y.

    2016-12-01

    Nitrogen dioxide (NO2) observations have been made using car Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) in Fukuoka, an urban area in Japan, to clarify the spatiotemporal inhomogeneity in NO2. We developed instruments for Car MAX-DOAS, and NO2 measurements were conducted on 15 August 2015 and 30 November 2015 on the Fukuoka Urban Expressway, along the closed circular route. For both days, in the morning, the maxima were observed around the city center (in the northeast part of the circular route), whereas in the afternoon, the maxima were observed in the south/southeast part of the circular route (to the south/southeast of the city center). Analysis of the surface wind field indicates that NO2 inhomogeneity is strongly related to the inhomogeneity of NOx sources and to horizontal transport of high concentrations from the city center and low concentrations from the ocean via a land-sea breeze.

  6. 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.

  7. Spin coated unsubstituted copper phthalocyanine thin films for nitrogen dioxide sensors

    NASA Astrophysics Data System (ADS)

    Chakane, Sanjay; Datir, Ashok; Koinkar, Pankaj

    2015-03-01

    Copper phthalocyanine (CuPc) is synthesized chemically and used for making CuPc thin films using spin coating technique. Films were prepared from trifluroacetic acid (TFA) and chlorobenzene mixed solution on the glass substrate. Spin coated films of unsubstituted CuPc films were heat annealed at 150°C for 2 h duration and were used to study NO2 gas sensing characteristics. α-phase of CuPc is noted by UV-visible absorption spectra. IR spectra of undoped CuPc films and doped CuPc films with NO2 revealed that, doping of nitrogen dioxide modifies and deletes some of the bands. The effect of NO2 at various concentrations from 50 ppm to 500 ppm in atmospheric air at room temperature on the electrical conductivity of CuPc films was studied. Sensitivity, response time and repeatability of the CuPc sensor were discussed in this paper.

  8. 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.

  9. 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%).

  10. Ice hockey lung – a case of mass nitrogen dioxide poisoning in the Czech Republic

    PubMed Central

    Brat, Kristian; Merta, Zdenek; Plutinsky, Marek; Skrickova, Jana; Ing, Miroslav Stanek

    2013-01-01

    Nitrogen dioxide (NO2) is a toxic gas, a product of combustion in malfunctioning ice-resurfacing machines. NO2 poisoning is rare but potentially lethal. The authors report a case of mass NO2 poisoning involving 15 amateur ice hockey players in the Czech Republic. All players were treated in the Department of Respiratory Diseases at Brno University Hospital in November 2010 – three as inpatients because they developed pneumonitis. All patients were followed-up until November 2011. Complete recovery in all but one patient was achieved by December 2010. None of the 15 patients developed asthma-like disease or chronic cough. Corticosteroids appeared to be useful in treatment. Electric-powered ice-resurfacing machines are preferable in indoor ice skating arenas. PMID:24032121

  11. Effects of nitrogen dioxide on allergic airway responses in subjects with asthma.

    PubMed

    Witten, Allyson; Solomon, Colin; Abbritti, Emilio; Arjomandi, Mehrdad; Zhai, Wenwu; Kleinman, Michael; Balmes, John

    2005-12-01

    We sought to determine whether nitrogen dioxide (NO2) can enhance airway inflammation after allergen challenge in asthmatic subjects. Fifteen house-dust-mite (HDM)-sensitive asthmatic subjects were exposed for 3 hours to filtered air or 0.4 ppm NO2, followed by inhalational challenge with HDM allergen. Markers of inflammation were measured in sputum at 6 hours and 26 hours after allergen challenge. After exposure to NO2, eosinophil concentration decreased significantly in the 6-hour postallergen sputum. No significant NO2-related difference was observed for other variables. Our results suggest that, in most asthmatic individuals, multi-hour exposure to a high ambient concentration of NO2 does not enhance the inflammatory response to subsequent inhaled allergen as assessed by cell distribution in induced sputum. Because the decrease in airway eosinophils has been reported in previous animal studies, future research should be directed toward the mechanism of this effect.

  12. Concurrent multiaxis differential optical absorption spectroscopy system for the measurement of tropospheric nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Leigh, Roland J.; Corlett, Gary K.; Friess, Udo; Monks, Paul S.

    2006-10-01

    The development of a new concurrent multiaxis (CMAX) sky viewing spectrometer to monitor rapidly changing urban concentrations of nitrogen dioxide is detailed. The CMAX differential optical absorption spectroscopy (DOAS) technique involves simultaneous spectral imaging of the zenith and off-axis measurements of spatially resolved scattered sunlight. Trace-gas amounts are retrieved from the measured spectra using the established DOAS technique. The potential of the CMAX DOAS technique to derive information on rapidly changing concentrations and the spatial distribution of NO2 in an urban environment is demonstrated. Three example data sets are presented from measurements during 2004 of tropospheric NO2 over Leicester, UK (52.62°N, 1.12°W). The data demonstrate the current capabilities and future potential of the CMAX DOAS method in terms of the ability to measure real-time spatially disaggregated urban NO2.

  13. 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.

  14. Ground-high altitude joint detection of ozone and nitrogen oxides in urban areas of Beijing.

    PubMed

    Chen, Pengfei; Zhang, Qiang; Quan, Jiannong; Gao, Yang; Zhao, Delong; Meng, Junwang

    2013-04-01

    Based on observational data of ozone (O3) and nitrogen oxide (NO(x)) mixing ratios on the ground and at high altitude in urban areas of Beijing during a period of six days in November 2011, the temporal and spatial characteristics of mixing ratios were analyzed. The major findings include: urban O3 mixing ratios are low and NO(x) mixing ratios are always high near the road in November. Vertical variations of the gases are significantly different in and above the planetary boundary layer. The mixing ratio of O3 is negatively correlated with that of NO(x) and they are positively correlated with air temperature, which is the main factor directly causing vertical variation of O3 and NO(x) mixing ratios at 600-2100 m altitude. The NO(x) mixing ratios elevated during the heating period, while the O3 mixing ratios decreased: these phenomena are more significant at high altitudes compared to lower altitudes. During November, air masses in the urban areas of Beijing are brought by northwesterly winds, which transport O3 and NO(x) at low mixing ratios. Due to Beijing's natural geographical location, northwest air currents are beneficial to the dilution and dispersion of pollutants, which can result in lower O3 and NO(x) background values in the Beijing urban area.

  15. No significant interactions between nitrogen stimulation and ozone inhibition of isoprene emission in Cathay poplar.

    PubMed

    Yuan, Xiangyang; Shang, Bo; Xu, Yansen; Xin, Yue; Tian, Yuan; Feng, Zhaozhong; Paoletti, Elena

    2017-12-01

    Isoprene emission from plants subject to a combination of ozone (O3) and nitrogen (N) has never been investigated. Cathay poplar (Populus cathayana) saplings were exposed to O3 (CF, charcoal-filtered air, NF, non-filtered ambient air and E-O3, non-filtered air +40ppb) and N treatments (N0, 0kgNha(-1)year(-1), N50, 50kgNha(-1)year(-1) and N100, 100kgNha(-1)year(-1)) for 96days. Increasing O3 exposure decreased isoprene emission (11.5% in NF and 57.9% in E-O3), as well as light-saturated photosynthetic rate (Asat) and chlorophyll content, while N load increased isoprene emission (19.6% in N50 and 33.4% in N100) as well as Asat and chlorophyll content. Although O3 and N interacted significantly in Asat, N did not mitigate the negative effects of O3 on isoprene emission, i.e. the combined effects were additive and did not interact. These results warrant more research on the combined effects of co-existing global change factors on future isoprene emission and atmospheric chemical processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. 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

  17. 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.

  18. [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.

  19. Biocompatibility and antibacterial activity of nitrogen-doped titanium dioxide nanoparticles for use in dental resin formulations.

    PubMed

    Zane, Andrew; Zuo, Ranfang; Villamena, Frederick A; Rockenbauer, Antal; Digeorge Foushee, Ann Marie; Flores, Kristin; Dutta, Prabir K; Nagy, Amber

    The addition of antibacterial functionality to dental resins presents an opportunity to extend their useful lifetime by reducing secondary caries caused by bacterial recolonization. In this study, the potential efficacy of nitrogen-doped titanium dioxide nanoparticles for this purpose was determined. Nitrogen doping was carried out to extend the ultraviolet absorbance into longer wavelength blue light for increased biocompatibility. Titanium dioxide nanoparticles (approximately 20-30 nm) were synthesized with and without nitrogen doping using a sol-gel method. Ultraviolet-Visible spectroscopy indicated a band of trap states, with increasing blue light absorbance as the concentration of the nitrogen dopant increased. Electron paramagnetic resonance measurements indicated the formation of superoxide and hydroxyl radicals upon particle exposure to visible light and oxygen. The particles were significantly toxic to Escherichia coli in a dose-dependent manner after a 1-hour exposure to a blue light source (480 nm). Intracellular reactive oxygen species assay demonstrated that the particles caused a stress response in human gingival epithelial cells when exposed to 1 hour of blue light, though this did not result in detectable release of cytokines. No decrease in cell viability was observed by water-soluble tetrazolium dye assay. The results show that nitrogen-doped titanium dioxide nanoparticles have antibacterial activity when exposed to blue light, and are biocompatible at these concentrations.

  20. Biocompatibility and antibacterial activity of nitrogen-doped titanium dioxide nanoparticles for use in dental resin formulations

    PubMed Central

    Zane, Andrew; Zuo, Ranfang; Villamena, Frederick A; Rockenbauer, Antal; Digeorge Foushee, Ann Marie; Flores, Kristin; Dutta, Prabir K; Nagy, Amber

    2016-01-01

    The addition of antibacterial functionality to dental resins presents an opportunity to extend their useful lifetime by reducing secondary caries caused by bacterial recolonization. In this study, the potential efficacy of nitrogen-doped titanium dioxide nanoparticles for this purpose was determined. Nitrogen doping was carried out to extend the ultraviolet absorbance into longer wavelength blue light for increased biocompatibility. Titanium dioxide nanoparticles (approximately 20–30 nm) were synthesized with and without nitrogen doping using a sol–gel method. Ultraviolet–Visible spectroscopy indicated a band of trap states, with increasing blue light absorbance as the concentration of the nitrogen dopant increased. Electron paramagnetic resonance measurements indicated the formation of superoxide and hydroxyl radicals upon particle exposure to visible light and oxygen. The particles were significantly toxic to Escherichia coli in a dose-dependent manner after a 1-hour exposure to a blue light source (480 nm). Intracellular reactive oxygen species assay demonstrated that the particles caused a stress response in human gingival epithelial cells when exposed to 1 hour of blue light, though this did not result in detectable release of cytokines. No decrease in cell viability was observed by water-soluble tetrazolium dye assay. The results show that nitrogen-doped titanium dioxide nanoparticles have antibacterial activity when exposed to blue light, and are biocompatible at these concentrations. PMID:27980404