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

    PubMed

    Lindvall, T

    1985-01-01

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

  3. 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.

  4. 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.

  5. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. The response of ozone and nitrogen dioxide to the eruption of Mt. Pinatubo at southern and northern midlatitudes

    NASA Astrophysics Data System (ADS)

    Aquila, V.; Oman, L.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.

    2012-12-01

    Observations have shown that the global mass of nitrogen dioxide decreased at midlatitudes in both hemispheres in the year following the eruption of Mt. Pinatubo, indicating an enhanced heterogeneous chemistry due to the presence of the volcanic aerosol. In contrast, the observed ozone response at southern and northern midlatitudes was largely asymmetrical with respect to the equator, with a general decrease at northern midlatitudes and little change and even a small increase at southern midlatitudes. Simulations including enhanced heterogeneous chemistry but no other direct effects of the volcanic aerosol reproduce a decrease of ozone in both hemispheres, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and, subsequently, the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol.

  3. 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.

  4. 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.

  5. 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.

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

    SciTech Connect

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

    1988-12-01

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

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

    PubMed

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

    2009-06-01

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

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

    PubMed

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

    2014-01-01

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

  9. 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).

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Product analyses of ozone mediated nitration of benzimidazole derivatives with nitrogen dioxide: formation of 1-nitrobenzimidazoles and conversion to benzotriazoles.

    PubMed

    Kaiya, Toyo; Nakamura, Kei; Tanaka, Masaru; Miyata, Naoki; Kohda, Kohfuku

    2004-05-01

    Several benzimidazole derivatives having electron-withdrawing or -donating substituent(s) at the benzene moiety were used as models of the imidazole moiety of purine bases and their nitration with nitrogen dioxide and ozone (so-called Kyodai nitration) were examined. Products were extracted from the reaction mixture with AcOEt and their structures were analyzed. 1-Nitrobenzimidazole derivatives and unexpected 1-nitrobenzotriazole derivatives were identified. Although the yields of 1-nitrobenzimidazole derivatives were quite low, these were all new compounds that could be obtained only by Kyodai nitration. It was speculated that benzotriazoles were formed via 1-nitrobenzimidazoles and subsequent nitration toward benzotriazoles resulted in the formation of 1-nitrobenzotriazoles. PMID:15133210

  15. 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.

  16. Data assimilation of satellite-retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS

    NASA Astrophysics Data System (ADS)

    Inness, A.; Blechschmidt, A.-M.; Bouarar, I.; Chabrillat, S.; Crepulja, M.; Engelen, R. J.; Eskes, H.; Flemming, J.; Gaudel, A.; Hendrick, F.; Huijnen, V.; Jones, L.; Kapsomenakis, J.; Katragkou, E.; Keppens, A.; Langerock, B.; de Maziere, M.; Melas, D.; Parrington, M.; Peuch, V. H.; Razinger, M.; Richter, A.; Schultz, M. G.; Suttie, M.; Thouret, V.; Vrekoussis, M.; Wagner, A.; Zerefos, C.

    2015-05-01

    Daily global analyses and 5-day forecasts are generated in the context of the European Monitoring Atmospheric Composition and Climate (MACC) project using an extended version of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The IFS now includes modules for chemistry, deposition and emission of reactive gases, aerosols, and greenhouse gases, and the 4-dimensional variational data assimilation scheme makes use of multiple satellite observations of atmospheric composition in addition to meteorological observations. This paper describes the data assimilation setup of the new Composition-IFS (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation. The largest improvement in CO by assimilation of Measurements of Pollution in the Troposphere (MOPITT) CO columns is seen in the lower troposphere of the Northern Hemisphere (NH) extratropics during winter, and during the South African biomass-burning season. The assimilation of several O3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O3 analysis fields relative to the control run. The impact on lower tropospheric ozone, which comes from the residual of the total column and stratospheric profile O3 data, is smaller, but nevertheless there is some improvement particularly in the NH during winter and spring. The impact of the assimilation of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) is small because of the short lifetime of NO2, suggesting that NO2 observations would be better used to adjust emissions instead of initial conditions. The results further indicate that the quality of the tropospheric analyses and of the stratospheric ozone analysis obtained with the C-IFS system has improved compared to

  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. Stratospheric ozone and nitrogen dioxide total column and vertical profiles in southern Portugal during 2004-2007

    NASA Astrophysics Data System (ADS)

    Bortoli, D.; Silva, A. M.; Roselli, D.; Giovanelli, G.

    2007-10-01

    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed by the collaboration between CGE-UE, ISAC-CNR and ENEA. SPATRAM is a multi-purpose UV-Vis-NIR spectrometer (250-950 nm). It is installed at the Observatory of the CGE since April 2004 and actually it is utilized to carry-out measurements of the zenith scattered radiation, the so-called "Passive mode", in order to retrieve-by application of DOAS (Differential Optical Absorption Spectroscopy) methodology-the vertical content of some atmospheric tracers such as Ozone (O3) and Nitrogen Dioxide (NO2). For the continuous NO2 monitoring the 425-455 nm spectral region is investigated. For the Ozone retrieval the spectral interval 320-340 nm is chosen. In this study, after a brief description of the instrument, a short explanation of the DOAS methodology and of the inversion algorithms used for the determination of the vertical distribution of the some atmospheric compounds are provided. The obtained results in terms of diurnal and seasonal variation of O3 and NO2 total column are presented. The measurements are in good agreement with the photochemical theory of NO2 and O3, showing the maximum values during the summer season and the minimum during the winter. In addition the application, to the output of the DOAS program, of sophisticated inversion schemes, using the Air Mass Factor (AMF) matrix as the kernel of the inversion algorithm, allowed for the determination of vertical distribution of some atmospheric tracers. The results obtained for NO2 and O3 are presented and discussed.

  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. 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...

  2. 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

  3. 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

  4. Combined effects of ozone and nitrogen dioxide on respiratory function in man

    SciTech Connect

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

    1981-07-01

    Ten young adult males were exposed to either filtered air or 0.50 ppM ozone plus 0.50 ppM NO/sub 2/ in filtered air under four environmental conditions: 25/sup 0/C, 45% rh; 30/sup 0/C, 85% rh; 35/sup 0/C, 40% rh; and 40/sup 0/C, 50% rh. There were eight 2-hour exposures per subject. After 1 hour of sitting exposure the subjects exercised for 30 minutes which increased ventilatory exchange to approximately 40 L/min. Pulmonary function tests were performed before, during, and after exposure. Metabolism and ventilation were determined during the last 15 minutes of exercise. A symptom questionnaire was completed at the termination of each exposure following reexamination by a physician. There was a decrease in vital capacity, inspiratory capacity, and several flow-related measures of lung function during exposure. The response to exposure to the combined pollutants was similar to that observed in ozone exposures alone. No synergism was observed.

  5. Retrieval of stratospheric ozone and nitrogen dioxide profiles from Odin Optical Spectrograph and Infrared Imager System (OSIRIS) limb-scattered sunlight measurements

    NASA Astrophysics Data System (ADS)

    Haley, Craig Stuart

    2009-12-01

    Key to understanding and predicting the effects of global environmental problems such as ozone depletion and global warming is a detailed understanding of the atmospheric processes, both dynamical and chemical. Essential to this understanding are accurate global data sets of atmospheric constituents with adequate temporal and spatial (vertical and horizontal) resolutions. For this purpose the Canadian satellite instrument OSIRIS (Optical Spectrograph and Infrared Imager System) was launched on the Odin satellite in 2001. OSIRIS is primarily designed to measure minor stratospheric constituents, including ozone (O3) and nitrogen dioxide (NO2), employing the novel limb-scattered sunlight technique, which can provide both good vertical resolution and near global coverage. This dissertation presents a method to retrieve stratospheric O 3 and NO2 from the OSIRIS limb-scatter observations. The retrieval method incorporates an a posteriori optimal estimator combined with an intermediate spectral analysis, specifically differential optical absorption spectroscopy (DOAS). A detailed description of the retrieval method is presented along with the results of a thorough error analysis and a geophysical validation exercise. It is shown that OSIRIS limb-scatter observations successfully produce accurate stratospheric O3 and NO2 number density profiles throughout the stratosphere, clearly demonstrating the strength of the limb-scatter technique. The OSIRIS observations provide an extremely useful data set that is of particular importance for studies of the chemistry of the middle atmosphere. The long OSIRIS record of stratospheric ozone and nitrogen dioxide may also prove useful for investigating variability and trends.

  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. Nitrogen dioxide measurement by cavity attenuated phase shift spectroscopy (CAPS) and implications in ozone production efficiency and nitrate formation in Beijing, China

    NASA Astrophysics Data System (ADS)

    Ge, Baozhu; Sun, Yele; Liu, Ying; Dong, Huabin; Ji, Dongsheng; Jiang, Qi; Li, Jie; Wang, Zifa

    2013-08-01

    dioxide (NO2) is a key species in studying photochemical smog and formation mechanisms of nitrate in fine particles. However, the conventional commercially available chemiluminescence (CL)-based method often has uncertainties in measuring NO2 because of interferences with other reactive nitrogen species. In this study, an Aerodyne Cavity Attenuated Phase Shift Spectroscopy (CAPS) NO2 monitor that essentially has no interferences with nitrogen containing species was deployed in Beijing for the first time during August 2012. The CAPS NO2 monitor is highly sensitive with a detection limit (3σ) of 46.6 ppt for 1 min integration. The NO2 measured by CAPS shows overall agreement with that from CL, yet large differences up to 20% were also observed in the afternoon. Further, the discrepancies of NO2 measurements between CAPS and CL appear to be NOz dependent with larger differences at higher NOz concentrations (e.g., > 14 ppb). As a result, the ozone production efficiency of NOx (OPEx) derived from the correlations of Ox-NOz with the CL NO2 can be overestimated by 19-37% in Beijing. The daily OPEx calculated with the CAPS NO2 ranges from 1.0 to 6.8 ppb/ppb with an average (±1σ) of 2.6 (±1.3) for the entire study. The relatively low OPEx and the relationship between OPEx and NOx suggest that ozone production chemistry is VOC sensitive during summer in Beijing. Two case studies further show that high concentrations of NOx can significantly enhance the formation of nitrate in fine particles in the presence of high O3 and favorable meteorological conditions.

  9. 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.

  10. Spatial and temporal analysis of ground level ozone and nitrogen dioxide concentration across the twin cities of Pakistan.

    PubMed

    Ahmad, Sheikh Saeed; Aziz, Neelam

    2013-04-01

    The analyses presented in this paper include the concentration levels of NO2 and O3 measured during 2 successive years in twin cities (Rawalpindi and Islamabad) of Pakistan from November 2009 to March 2011. NO2 was determined using the passive sampling method, while ozone was determined by Model 400E ozone analyzer. The average NO2 and O3 concentration in twin cities of Pakistan was found to be 44 ± 6 and 18.2 ± 1.24 ppb, respectively. Results indicate that the concentration of NO2 and O3 show seasonal variations. Results also depict that NO2 and O3 concentration levels are high in areas of intense traffic flow and congestion. Rawalpindi has more elevated levels of NO2 and O3 as compared to the Islamabad due to the narrow roads, enclosing architecture of road network and congestion. Climatic variables also influenced the NO2 and O3 concentration, i.e., temperature is positively related with O3, while negatively related with NO2, relative humidity is directly related with NO2 and inversely related with O3, whereas rainfall show negative association with both NO2 and O3 concentration. Comparing the results with WHO standards reveals that NO2 concentration levels at all the sampling points are above the permissible limit, while ozone concentration is still lower than the WHO standards. Thus, there is a need to take appropriate steps to control these continuously increasing levels of NO2 and O3 before they become a serious hazard for the environment and people living in those areas.

  11. 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

  12. 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.

  13. 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.).

  14. 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

  15. 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.

  16. Dry deposition of nitrogen compounds (NO2, HNO3, NH3), sulfur dioxide and ozone in West and Central African ecosystems using the inferential method

    NASA Astrophysics Data System (ADS)

    Adon, M.; Galy-Lacaux, C.; Yoboue, V.; Delon, C.; Solmon, F.; Kaptue Tchuente, A. T.

    2013-05-01

    This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long term monitoring of gas concentrations (1998-2007) established on seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2, and O3) and on the other hand simulated dry deposition velocities (Vd). Vd were calculated using the big-leaf model of Zhang et al. (2003b). In the model of deposition, surface and meteorological conditions specific to IDAF sites have been adapted in order to simulate Vd representative of major African ecosystems. The monthly, seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3, and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from 0.4 ± 0.0 to 0.8 ± 0.2 kg N ha-1 yr-1 for NO2, from 0.7 ± 0.1 to 1.0 ± 0.3 kg N ha-1 yr-1 for HNO3, and from 2.3 ± 0.8 to 10.5 ± 5.0 kg N ha-1 yr-1 for NH3 over the study period (1998-2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (11.2-11.8 kg N ha-1 yr-1) than in wet and dry savannas (3.4-5.3 kg N ha-1 yr-1). NH3 dominated nitrogen dry deposition, representing 67-80% of the total. The annual mean dry deposition fluxes of ozone range between 11.3 ± 4.7 and 17.5 ± 3.0 kg ha-1 yr-1 in dry savannas, 17.5 ± 3.0 and 19.2 ± 2.9 kg ha-1 yr-1 in wet savannas, and 10.6 ± 2.0 and 13.2 ± 3.6 kg ha-1 yr-1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower of a factor of 2-3, compared to others ecosystems. Along the ecosystem transect, annual mean of SO2 dry deposition fluxes present low values and a small variability (0.5 to 1 kg S ha-1 yr-1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

  17. 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.

  18. Dry deposition of nitrogen compounds (NO2, HNO3, NH3), sulfur dioxide and ozone in west and central African ecosystems using the inferential method

    NASA Astrophysics Data System (ADS)

    Adon, M.; Galy-Lacaux, C.; Delon, C.; Yoboue, V.; Solmon, F.; Kaptue Tchuente, A. T.

    2013-11-01

    This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long-term monitoring of gas concentrations (1998-2007) established at seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on the one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2 and O3) and on the other hand modeled exchange rates. Dry deposition velocities (Vd) were calculated using the big-leaf model of Zhang et al. (2003b). The bidirectional approach is used for NH3 surface-atmosphere exchange (Zhang et al., 2010). Surface and meteorological conditions specific to IDAF sites have been used in the models of deposition. The seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3 and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from -0.4 to -0.8 kg N ha-1 yr-1 for NO2, from -0.7 to -1.0 kg N ha-1 yr-1 for HNO3 and from -0.7 to -8.3 kg N ha-1 yr-1 for NH3 over the study period (1998-2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (-10 kg N ha-1 yr-1) than in wet and dry savannas (-1.6 to -3.9 kg N ha-1 yr-1). The annual mean dry deposition fluxes of ozone range between -11 and -19 kg ha-1 yr-1 in dry and wet savannas, and -11 and -13 kg ha-1 yr-1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower by a factor of 2-3, compared to other ecosystems. Along the ecosystem transect, the annual mean of SO2 dry deposition fluxes presents low values and a small variability (-0.5 to -1 kg S ha-1 yr-1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

  19. 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

  20. Impact of future nitrous oxide and carbon dioxide emissions on the stratospheric ozone layer

    NASA Astrophysics Data System (ADS)

    Stolarski, Richard S.; Douglass, Anne R.; Oman, Luke D.; Waugh, Darryn W.

    2015-03-01

    The atmospheric levels of human-produced chlorocarbons and bromocarbons are projected to make only small contributions to ozone depletion by 2100. Increases in carbon dioxide (CO2) and nitrous oxide (N2O) will become increasingly important in determining the future of the ozone layer. N2O increases lead to increased production of nitrogen oxides (NOx), contributing to ozone depletion. CO2 increases cool the stratosphere and affect ozone levels in several ways. Cooling decreases the rate of many photochemical reactions, thus slowing ozone loss rates. Cooling also increases the chemical destruction of nitrogen oxides, thereby moderating the effect of increased N2O on ozone depletion. The stratospheric ozone level projected for the end of this century therefore depends on future emissions of both CO2 and N2O. We use a two-dimensional chemical transport model to explore a wide range of values for the boundary conditions for CO2 and N2O, and find that all of the current scenarios for growth of greenhouse gases project the global average ozone to be larger in 2100 than in 1960.

  1. Indoor nitrogen dioxide and childhood respiratory illness.

    PubMed

    Pilotto, L S; Douglas, R M

    1992-09-01

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

  2. 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.

  3. 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...

  4. Collagen breakdown and nitrogen dioxide inhalation.

    PubMed

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

    1977-01-01

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

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  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...

  10. 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...

  11. 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.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    over Bologna is an instrumented Zepplin measuring NO2 and ozone among other species. A hemispherical panorama of nitrogen dioxide concentrations, as measured by the HSI-DOAS instrument in Bologna.

  14. 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...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  17. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  18. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  20. 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

  1. 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

  2. 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.

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

    PubMed

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

    1993-06-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  6. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  7. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  9. Does nitrogen dioxide exposure increase airways responsiveness

    SciTech Connect

    Folinsbee, L.J.

    1992-01-01

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

  10. 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.

  11. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  13. 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...

  14. 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... § 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. Nitrogen dioxide and respiratory illnesses in infants.

    PubMed

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

    1993-11-01

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

  5. 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.

  6. 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.

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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.

  13. Adsorption air cleaning from ozone.

    PubMed

    Baltrenas, Pranas; Paliulis, Dainius; Vasarevicius, Saulius; Simaitis, Ramutis

    2003-01-01

    Not much has been written about air cleaning from ozone. The aim of this paper was to demonstrate the possibility of adsorption air cleaning from ozone. The second aim was to investigate the dependence of the efficiency of ozone removal from the air on the height of the adsorber layer and on concentrations of ozone, and to obtain empirical formulas for calculating the efficiency of ozone treatment. Equipment for air cleaning from ozone and nitrogen and sulphur dioxides is suggested.

  14. 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

  15. 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.

  16. 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.…

  17. 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 ...

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

    PubMed

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

    2015-08-01

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

  20. Interactions of future climate, carbon dioxide, and ozone change crop and forest productivity and water use

    NASA Astrophysics Data System (ADS)

    Lombardozzi, D.; Bonan, G. B.; Levis, S.

    2014-12-01

    The demand for agricultural and forest yield will continually increase as populations grow, though it is unclear how agricultural and forested ecosystem productivity and water use will respond to the interactions of changing climate, carbon dioxide and ozone. In ecosystems essential to resource production, it is critical to understand how productivity and water use will respond to these future changes. Previous research suggests that future climate and ozone can each decrease crop and timber yield and water use efficiency, while future carbon dioxide might increase yield and improve water use efficiency. However, the change in agricultural and forest water use and yield in response to the interactions among these variables has not yet been determined. We use the Community Land Model (CLM) to determine how changes in agricultural and timber water use and yield in response to the interactions of all three variables (climate, carbon dioxide, and ozone). Preliminary results suggest that future ozone and climate decrease forest and grain yield. However, carbon dioxide concentrations increase forest and grain yield, offsetting the decreases. Future climate increases evapotranspiration in all regions more than the decreases caused by carbon dioxide and ozone. The interactions of climate, carbon dioxide, and ozone decrease water use efficiency, with climate having the largest impact. These results demonstrate that, to maintain agricultural and forest productivity in the future, the demand for irrigation will increase.

  1. Interactions of nitrogenous air pollutants and ozone with California forests

    SciTech Connect

    Bytnerowicz, A.

    1994-12-31

    Ozone has been blamed for the decline of ponderosa and Jeffrey pines in Sierra Nevada and the San Bernardino Mountains. However, also other components of photochemical smog, and especially various nitrogenous compounds, play an important role in the observed changes in California forests. Gaseous nitric acid and peroxyacetyl nitrate may directly effects plants (development of foliar injury) or may predispose foliage to the deleterious effects of acidic wet deposition, elevated levels of the UV-B radiation or other stresses. In addition, the long-term deposition of nitrate and ammonium in wet precipitation, dry deposition of gaseous nitric acid, ammonia, nitrogen oxides, particulate nitrate and ammonium can significantly change nitrogen status of forests in California. Initially, changes in phenology of plants, higher rates of physiological processes, changed plant chemical composition, altered biochemical processes and improved growth can be observed. These changes may lead to increased susceptibility of plants to various abiotic and biotic stresses. After long periods of increased nitrogen deposition, deficiencies of calcium, magnesium, potassium, phosphorus, and other nutrients may develop. As a consequence of the elevated N deposition interacting with ozone phytotoxicity, perturbations in normal growth of plants and changes in species composition in forest stands may be taking place. Oversaturating forests with nitrogen may also result in increased nitrate content in ground water of the affected watersheds.

  2. 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

  3. 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

  4. Effects of tropospheric ozone on methane and carbon dioxide fluxes from peatland mesocosms

    NASA Astrophysics Data System (ADS)

    Toet, Sylvia; Oliver, Vikki; Helgason, Thorunn; Peacock, Simon; Barnes, Jeremy; Ineson, Phil; Ashmore, Mike

    2010-05-01

    Tropospheric ozone is currently the third most important greenhouse gas, and also the most important gaseous air pollutant globally in terms of effects on vegetation world-wide. At present levels it poses a significant threat to crop yield and forest productivity of sensitive species, while background ozone concentrations are expected to increase further during the next decades. The potential importance of ozone in reducing carbon assimilation, and consequently in increasing atmospheric carbon dioxide concentrations, has been recognised. However, regional modelling studies are based on the impact of ozone on photosynthetic rates and above-ground growth, and do not consider effects of ozone on belowground carbon fluxes. The limited experimental data on the long-term effects of ozone on belowground carbon processes, mainly from arable crop and forest systems, are a major constraint to understanding the impacts of ozone on global carbon fluxes. Very little attention has been paid to ozone effects on peatland carbon dynamics, though northern peatlands store a third of the global soil organic carbon pool and are an important source of atmospheric methane. The aims of this study were to assess the long-term effects of elevated ozone on carbon dioxide and methane fluxes in temperate peatland mesocosms and to identify underlying plant, soil and microbial processes. Mesocosms from a wet heath (Isle of Skye, UK) with vegetation dominated by the peat moss Sphagnum papillosum and the sedge Schoenus nigricans have been exposed to ambient (control) and three elevated levels of ozone in open-top chambers from May 2008. Methane emission, carbon dioxide fluxes and relevant plant and soil variables were measured every 6 weeks (growing season) or 8 weeks (winter). Methane emissions were significantly reduced by elevated ozone over the first 18 months of the experiment. Ecosystem respiration only showed a significant increase in response to ozone in the second growing season, while

  5. 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.

  6. 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:...

  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:...

  8. 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:...

  9. 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:...

  10. 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:...

  11. 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.

  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. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  15. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  16. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  17. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  18. Ground based observations of stratospheric nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Syed, M. Q.; Harrison, A. W.

    1980-06-01

    The results of ground based measurements of stratospheric NO2, using four different established methods based on twilight sky observations in the spectral region 437.0-451.0 nm and made at two locations: Primrose Lake and at Priddis, Alberta, Canada, during March and April 1979 are presented. It is shown that the four methods differ from one another on the basis of: (a) whether or not stratospheric ozone is taken into account, (b) whether a continuous NO2 absorption spectrum or just the absorption at a few discrete wavelengths is used for analysis, and (c) the assumed altitude distribution of NO2 concentration. Further, two different independently developed altitude distribution models are employed in obtaining the NO2 vertical column abundance and its effective altitude from a set of slant column abundances measured in the twilight sky at different solar zenith angles in the range of 85 to 96 deg. Finally, a comparison shows that the use of one or the other of these two models alone could introduce a difference of as much as 30% in the derived vertical column abundance.

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

    PubMed

    Heller, R F; Gordon, R E

    1986-01-01

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

  20. 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 nitrogen. 52.136 Section 52.136 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of...

  1. 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 nitrogen. 52.136 Section 52.136 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of...

  2. 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 nitrogen. 52.136 Section 52.136 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of...

  3. 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 nitrogen. 52.136 Section 52.136 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of...

  4. 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 nitrogen. 52.136 Section 52.136 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of...

  5. 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.

  6. Uptake rate of nitrogen dioxide by potato plants

    SciTech Connect

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

    1984-06-01

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1998-08-01

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

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... nitrogen. 52.235 Section 52.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay... the area from implementing the oxides of nitrogen (NOX) requirements for reasonably available...

  19. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... nitrogen. 52.235 Section 52.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay... the area from implementing the oxides of nitrogen (NOX) requirements for reasonably available...

  20. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... nitrogen. 52.235 Section 52.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay... the area from implementing the oxides of nitrogen (NOX) requirements for reasonably available...

  1. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... nitrogen. 52.235 Section 52.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay... the area from implementing the oxides of nitrogen (NOX) requirements for reasonably available...

  2. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... nitrogen. 52.235 Section 52.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay... the area from implementing the oxides of nitrogen (NOX) requirements for reasonably available...

  3. 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.

  4. 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.

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

    DOE Data Explorer

    Ken Oglesby

    2010-01-01

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

  6. Vertical distribution of ozone and nitrogenous pollutants in an air quality class I area, the San Gorgonio wilderness, southern California.

    PubMed

    Alonso, Rocío; Bytnerowicz, Andrzej; Arbaugh, Michael

    2002-01-01

    Information about spatial and temporal distribution of air pollutants is essential for better understanding of environmental stresses affecting forests and estimation of potential risks associated with air pollutants. Ozone and nitrogenous air pollutants were monitored along an elevation gradient in the Class I San Gorgonio Wilderness area (San Bernardino Mountains, California, U.S.) during the summer of 2000 (mid-June to mid-October). Passive samplers were exposed for 2-week periods at six sampling sites located at 300 m intervals ranging from 1200 to 2700 m elevation. Elevated concentrations of ozone were found in this area with summer 24-h hourly means ranging from 53 to 59 ppb. The highest ozone concentrations were detected in the period July 25-August 8, reaching values of 64 to 72 ppb expressed as 2-week mean. Passive-sampler ozone data did not show a clear relationship with elevation, although during the periods with higher ozone levels, ozone concentrations were higher at those sites below 2000 m than at sites located above that elevation. All nitrogenous pollutants studied showed a consistent decrease of concentrations with elevation. Nitrogen dioxide (NO2) levels were low, decreasing with increasing elevation from 6.4 to 1.5 ppb summer means. Nitric oxide (NO) concentrations were around 1 to 2 ppb, which is within the range of the detection levels of the devices used. Nitric acid (HNO3) vapor concentrations were lower at higher elevations (summer means 1.9-2.5 microg m(-3) than at lower elevations (summer means 4.3-5.1 microg m(-3). Summer concentrations of ammonia (NH3) were slightly higher than nitric acid ranging from 6 microg m(-3) at the lowest site to 2.5 microg m(-3) registered at the highest elevation. Since complex interactions between ozone and nitrogenous air pollutants have already been described for forests, simultaneous information about the distribution of these pollutants is needed. This is particularly important in mountain terrain where

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:24604779

  12. 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.

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

    SciTech Connect

    Henriksson, E.; Pearson, L.C.

    1981-01-01

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

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

    SciTech Connect

    Gallon, A.A.

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Burgard, Daniel Alexander

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

  17. Large-scale nitrogen oxide plumes in the tropopause region and implications for ozone

    PubMed

    Brunner; Staehelin; Jeker

    1998-11-13

    Continuous measurements of nitrogen oxide and ozone were performed from a commercial airliner during 1 year at cruising altitudes below and above the tropopause. The upper tropospheric nitrogen oxides distribution was found to be strongly influenced by large-scale plumes extending about 100 to 1300 kilometers along the flight track. The plumes were frequently observed downwind of thunderstorms and frontal systems, which most probably caused upward transport of polluted air from the continental boundary layer or nitrogen oxide production in lightning strokes, or both. Particularly in summer, average ozone concentrations in the plumes were enhanced compared to the tropospheric background levels.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

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

    PubMed

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

    1997-11-01

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

  4. 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.

  5. 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

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

    SciTech Connect

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

    1989-05-01

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

  7. 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

    2015-09-01

    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

  8. 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

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  11. 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.

  12. 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.

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

    SciTech Connect

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

    1995-08-01

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

  14. 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

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

    PubMed

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

    2015-12-01

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

  16. 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.

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

    SciTech Connect

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

    1986-04-01

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

  18. 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

  19. 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.

  20. 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.

  1. 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).

  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. Model uncertainties affecting satellite-based inverse modeling of nitrogen oxides emissions and implications for surface ozone simulation

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    Errors in chemical transport models (CTMs) interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2) and emissions of nitrogen oxides (NOx) have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI) to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 22% in July and 10% in January. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitudes if the model is used for emission inversion without corrections. The modifications however

  4. 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.

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

    PubMed

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

    1998-09-01

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

  6. 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.

  7. 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.

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

    PubMed

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

    1997-10-01

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

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

    PubMed

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

    1995-09-01

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

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

    PubMed Central

    Mancinelli, R L; McKay, C P

    1983-01-01

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

  11. 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.

  12. 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.

  13. 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

  14. 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. PMID:25078062

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Spring leaf flush in aspen (Populus tremuloides) clones is altered by growth at elevated carbon dioxide and elevated ozone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early spring leaf out is important to the success of trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how elevated carbon dioxide concentration and elevated ozone concentration altered leaf area index development in a clos...

  20. 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...

  1. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

  5. Ozone Generation by a DC Driven Micro-Hollow Cathode Discharge in Nitrogen-Mixed Oxygen Flow

    NASA Astrophysics Data System (ADS)

    Yamatake, Atsushi; Yasuoka, Koichi; Ishii, Shozo

    2004-09-01

    The ozone generation characteristic of a DC driven micro-hollow cathode discharge was studied in nitrogen-mixed oxygen gas flow. An ozone concentration of 13.7 g/Nm3 was obtained at an efficiency of 97 g/kWh in pure oxygen. However, ozone concentrations of 8.2 g/Nm3 and 25 ppm ozone were obtained in gas mixtures of 4% and 80% N2-mixed oxygen gases, respectively. There was a threshold specific energy above which ozone concentration markedly decreased. High-energy electrons dissociate the nitrogen molecules and generate NO and NO2 which accelerate the ozone decomposition in high-power-density plasmas such as a micro-hollow cathode discharge.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:14658160

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

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  13. 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

  14. 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

  15. Improved spectral fitting of nitrogen dioxide from OMI in the 405-465 nm window

    NASA Astrophysics Data System (ADS)

    van Geffen, J. H. G. M.; Boersma, K. F.; Van Roozendael, M.; Hendrick, F.; Mahieu, E.; De Smedt, I.; Sneep, M.; Veefkind, J. P.

    2014-10-01

    An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405-465 nm spectral region is presented. Since the launch of OMI on board NASA's EOS-Aura satellite in 2004, DOAS retrievals of NO2 slant column densities have been the starting point for the KNMI DOMINO (v2.0) and NASA SP (v2.1) retrievals. However, recent intercomparisons between NO2 retrievals from OMI and other UV/Vis and limb spectrometers, as well as ground-based measurements, clearly suggested that OMI stratospheric NO2 is biased high. This study revises the OMI NO2 retrieval in detail. The representation of the OMI slit function to convolve high-resolution reference spectra onto the relevant spectral grid is improved. The window used for the wavelength calibration is optimised, leading to much-reduced fitting errors. Ozone and water vapour spectra used in the fit are updated, reflecting the recently improved knowledge on their absorption cross section as documented in the literature. The improved spectral fit also accounts for absorption by the O2-O2 collision complex and by liquid water over clear-water areas. The main changes in the improved spectral fitting result from the updates related to the wavelength calibration: the RMS error of the fit is reduced by 23% and the NO2 slant column by 0.85 × 1015 molec cm-2, independent of latitude, solar zenith angle and NO2 value. Including O2-O2 and liquid water absorption and updating the O3 and water vapour cross-section spectra further reduces NO2 slant columns on average by 0.35 × 1015 molec cm-2, accompanied with a further 9% reduction in the RMS error of the fit. The improved OMI NO2 slant columns are consistent with independent NO2 retrievals to within a range that can be explained by photo-chemically driven diurnal increases in stratospheric NO2 and by small differences in fitting window and fitting approach. The revisions indicate that current OMI NO2 slant columns suffered mostly from an

  16. Simultaneous determination of nitrogen dioxide and peroxyacetyl nitrate in ambient atmosphere by carbon-coated annular diffusion denuder

    NASA Astrophysics Data System (ADS)

    De Santis, F.; Allegrini, I.; Di Filippo, P.; Pasella, D.

    A diffusion denuder for simultaneous collection of ambient nitrogen dioxide and peroxyacetyl nitrate (PAN), based on quantitative collection on an alkaline active carbon surface, has been developed. Nitrogen dioxide yields nitrite anion whereas PAN yields nitrate which are extracted after sampling with water and analysed by ion chromatography. Laboratory and field tests concerning sorption efficiency, effect of humidity and capacity were carried out. The pre-exponential and exponent for the first term of the Gormley-Kennedy equation applied to annular geometry were estimated. It was found that for PAN the agreement between the experimental and calculated values is quite good and compatible with a "perfect sink" behaviour of carbon, whereas, in the case of NO 2, the experimental collection efficiency is lower than theory but still suitable for ambient sampling. Nitrogen oxide and ozone do not interfere in the determination. SO 2, HONO and HNO 3 which could interfere can be removed by using two diffusion denuders placed in line before the carbon denuder: one coated with tetrachloromercurate (TCM), for the removal of SO 2 and HNO 3, and the second, coated with carbonate, for the removal of HONO. The detection limit for 24 h sampling is better than 0.05 and 0.06 ppb for NO 2 and PAN, respectively. The response for NO 2 was compared during a field campaign in Milan with the corresponding integrated response of a chemiluminescence analyser, while data for PAN were compared with the integrated response of a GC-ECD technique. The results obtained are reported and discussed.

  17. 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.

  18. 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.

  19. 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)

  20. Production of ozone and nitrogen oxides by laser filamentation

    SciTech Connect

    Petit, Yannick; Henin, Stefano; Kasparian, Jerome; Wolf, Jean-Pierre

    2010-07-12

    We have experimentally measured that laser filaments in air generate up to 10{sup 14}, 3x10{sup 12}, and 3x10{sup 13} molecules of O{sub 3}, NO, and NO{sub 2}, respectively. The corresponding local concentrations in the filament active volume are 10{sup 16}, 3x10{sup 14}, and 3x10{sup 15} cm{sup -3}, and allows efficient oxidative chemistry of nitrogen, resulting in concentrations of HNO{sub 3} in the parts per million range. The latter forming binary clusters with water, our results provide a plausible pathway for the efficient nucleation recently observed in laser filaments.

  1. 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 ...

  2. The effect of operational parameters of the process of sludge ozonation on the solubilisation of organic and nitrogenous compounds.

    PubMed

    Manterola, G; Uriarte, I; Sancho, L

    2008-06-01

    An evaluation of various operational parameters on the process of sludge ozonation was carried out based on semi-batch experiments. Particular reference has been given to examine the main parameters affecting the solubilisation of organic matter and nitrogenous compounds. Various sets of experiments were undertaken using real sewage sludge to feed a semi-industrial ozonation plant. Applying ozone dosages between 25 and 35 mg O(3)/gTSS, the organic matter solubilisation obtained through ozonation increases proportionally to ozone dosage until a maximum value of 430 mg COD/L. Concerning the nitrogenous compounds, no variation in nitrite concentration and a low increase in nitrate concentration were attained, regardless of the applied ozone dosage. Little increase in ammonia concentration was achieved for low ozone dosages, whilst applying dosages higher than 20 mg O(3)/gTSS, the variation of ammonia increased proportionally with ozone dosage. Experiments using hydraulic retention time (HRT) between 10 and 60 min resulted in a similar COD solubilisation, confirming a rapid rate of cell lysis during ozonation of sludge. PMID:18466950

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

    PubMed

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

    2009-01-01

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

  4. 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 ...

  5. 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

  6. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  7. 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...

  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. 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.

  11. 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

  12. 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.

  13. [Purification of lake water using a combined ozonization, filtration and chlorine dioxide treatments. Experience with the water of Garda lake].

    PubMed

    Zanetti, F; Leoni, E; Muccioli, S; Ambrogiani, E; Sacchetti, R

    2005-01-01

    The hygienic characteristics of the freshwater from Garda Lake used for the water supply of Sirmione were evaluated before and during the various phases of treatment. The samples were taken at the moment of entry, after ozonization, after filtration and after the addition of chlorine dioxide. The coliforms and Escherichia coli, occasionally detected in the incoming water, were reduced by ozone and eliminated by filtration. Enterococci were always absent. The overall reduction in the total bacteria count was satifactory, considering the low initial levels (96.0% and 83.0% respectively for the Heterotrophic plate count at 22 degrees and the Heterotrophic plate count at 36 degrees). The chemical and physical indicators that underwent the greatest reductions were the sulphates, iron, manganese, ammonia and the turbidity. Several species of unicellular algae belonging to Chlorophyta, Cyanophyta and Bacillariophyta were identified in the water at entry and after ozonization, but were completely eliminated during the subsequent phase of filtration. deliver of high quality services.

  14. 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.

  15. 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.

  16. Vertical variation in canopy structure and CO(2) exchange of oak-maple forests: influence of ozone, nitrogen, and other factors on simulated canopy carbon gain.

    PubMed

    Reich, P. B.; Ellsworth, D. S.; Kloeppel, B. D.; Fownes, J. H.; Gower, S. T.

    1990-12-01

    Stand-level and physiological measurements were made for oak and maple species common in Wisconsin forests. Scaling relationships were identified to allow the development of a model for estimating net carbon exchange at the levels of a leaf, canopy stratum, and whole canopy. Functional relationships were determined between tissue gas exchange rates and perceived controlling variables. Vertical variation in leaf properties and in the distribution of foliage by weight, area, and species were characterized for several closed canopy forests. Forest canopies were divided into four horizontal strata to develop predictive models for canopy gas exchange. Leaf and canopy layer carbon dioxide exchange rates were predicted using leaf nitrogen concentration, leaf mass per area, ozone exposure, predawn leaf water potential, photosynthetically active radiation, and vapor pressure deficit as driving variables. Direct measurements of leaf gas exchange were used to validate the components (subroutines) of the model. Net carbon dioxide exchange was simulated for canopy layers at 5-min intervals over a diurnal time course. Simulations of canopy CO(2) exchange were made for a 30-m tall, mixed oak-maple forest under hypothetical ambient and greater-than-ambient ozone pollution regimes. Daily canopy net CO(2) exchange was predicted for seven forest stands and compared with estimates of aboveground net primary production, N availability, leaf area index, and canopy N.

  17. 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.

  18. Sulfur dioxide emissions from Peruvian copper smelters detected by the Ozone Monitoring Instrument

    NASA Astrophysics Data System (ADS)

    Carn, S. A.; Krueger, A. J.; Krotkov, N. A.; Yang, K.; Levelt, P. F.

    2007-05-01

    We report the first daily observations of sulfur dioxide (SO2) emissions from copper smelters by a satellite-borne sensor - the Ozone Monitoring Instrument (OMI) on NASA's EOS/Aura spacecraft. Emissions from two Peruvian smelters (La Oroya and Ilo) were detected in up to 80% of OMI overpasses between September 2004 and June 2005. SO2 production by each smelter in this period is assessed and compared with contemporaneous emissions from active volcanoes in Ecuador and southern Colombia. Annual SO2 discharge from the Ilo smelter, La Oroya smelter, and volcanoes in 2004-2005 is estimated and amounts to 0.3-0.1 +0.2, 0.07 +/- 0.03, and 1.2 +/- 0.5 Tg, respectively. This study confirms OMI's potential as an effective tool for evaluation of anthropogenic and natural SO2 emissions. Smelter plumes transport an array of toxic metals in addition to SO2 and continued monitoring to mitigate health and environmental impacts is recommended.

  19. Combined Water and the Ion Exchange Characteristics of Manganese Dioxide Produced by Ozonation.

    PubMed

    Contreras; Lapidus

    1999-05-01

    The change in ion exchange properties of manganese dioxide produced by ozonation (OMD) was studied with respect to its preheated temperature. This was performed by heating samples to different temperatures and later, saturating a part of them in aqueous cadmium sulfate solutions. Analyses were practiced on both the cadmium ion exchanged and un-ion exchanged samples. Results showed that the ion exchange reaction followed a stoichiometric relation between the hydrogen and cadmium ions, promoted by the combined water. The molar ratio of combined water to exchanged cadmium was found to be five. X rays and photographs taken in the scanning electron microscope showed that the structure and morphology of the OMD were not modified by the insertion of the cadmium during ion exchange. From the X rays, the structure of the OMD was determined to be of the gamma type. When the samples were heated to 400 and 500 degrees C, the crystal structure changed to beta and finally to Mn2O3, respectively. However, the changes in structure alone apparently did not affect the ion exchange. The surface area, measured by the BET technique, diminished linearly with the preheat temperature. The ion exchanged cadmium and the surface area showed a nonlinear relationship. However, the surface area and the quantity of combined water in the OMD were both linearly affected by preheating and are directly related to the ion exchange capacity. Copyright 1999 Academic Press.

  20. Vertical gradients of ozone and carbon dioxide within a deciduous forest in Central Pennsylvania.

    PubMed

    Skelly, J M; Fredericksen, T S; Savage, J E; Snyder, K R

    1996-01-01

    Ambient concentrations of ozone (O(3)) and carbon dioxide (CO(2)) were measured at locations from the forest floor to the top of the canopy in a deciduous forest at the Moshannon State Forest in northcentral Pennsylvania. O(3) concentrations were measured from May-September for three years (1993-1995) while CO(2) concentrations were measured only during July and August of 1994. O(3) concentrations increased steadily during the day at all locations, peaking during the middle to late afternoon hours. O(3) concentrations then steadily declined to their lowest point, just before dawn. Vertical O(3) concentration gradients varied seasonally and among years. However, O(3) concentrations were highest within the forest canopy and lowest at the forest floor, with an average difference of approximately 13%. Differences in O(3) concentrations between the canopy and forest floor were greatest at night. O(3) concentrations were slightly higher at locations within the canopy than above the canopy. CO(2) concentrations were consistenly higher near the forest floor and were higher above the canopy than within the canopy. CO(2) concentrations were higher at night than during the day at all locations, especially near the forest floor.

  1. Reactive nitrogen and its correlation with ozone in the lower Stratosphere and upper Troposhere

    SciTech Connect

    Murphy, D.M.; Fahey, D.W.; Liu, S.C.; Kelly, K.K. ); Proffitt, M.H.; Eubank, C.S.; Kawa, S.R. Univ. of Colorado, Boulder ); Chan, K.R. )

    1993-05-20

    The authors report on measurements of reactive nitrogen NO[sub y] and ozone O[sub 3] densities, and their correlations, in the lower stratosphere and upper troposphere as part of the Stratosphere-Troposphere Exchange Project (STEP), Airborne Antarctic Ozone Experiment (AAOE), and Airborne Arctic Stratospheric Expedition (AASE). Measurements were made from ER-2 aircraft in all these experiments. Reactive nitrogen measurements allow one to look at the total nitrogen load as it relates to atmospheric chemistry, and not have to follow each species and the complicated relationships they have in the atmosphere. A strong correlation is found between NO[sub y] and O[sub 3] in the lower stratosphere, but it is much weaker in the upper troposphere. Data is presented as the ratio of the two, and compared with model calculations, where an observed gradient from the tropics toward mid latitudes is not seen in the models. Lightning production of NO[sub y] may account for the lack of correlation in the upper troposphere. NO[sub y] condensation onto aerosols can also affect observed concentrations. In the tropical regions there are significant enough NO[sub y] densities in the upper troposphere to allow convective transport into the stratosphere.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    PubMed

    Kripke, B J; Sherwin, R P

    1984-05-01

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

  8. The retrieval of the concentrations of nitric oxide and nitrogen dioxide from satellite solar occultation measurements at sunset and sunrise

    SciTech Connect

    Cartalis, C.I.

    1989-01-01

    HALOE (Halogen Occultation Experiment), scheduled to fly on the Upper Atmosphere Research Satellite (UARS) in 1991, aims to retrieve the vertical concentration profiles of seven minor stratospheric constituents in order to improve the understanding of ozone's photochemistry. This dissertation concentrates on the retrieval of the concentrations of nitric oxide and nitrogen dioxide, which both play an active role in the photochemistry of ozone. The investigation is complicated because of their large diurnal changes which are intensified at sunrise and sunset. Consequently, the retrieval of NO and NO{sub 2} from solar occultation measurements at twilight needs to take into account the lifetimes and the rapid interconversion of NO and NO{sub 2}. If the temporal and spatial variations of NO and NO{sub 2} are neglected, the resulting errors for altitudes less than 20 km reach 100 and 5% respectively and for both sunset and sunrise. A photochemical scheme is developed and a separate code calculates the photodissociation rates of the species involved in photochemical reactions, as a function of latitude, temperature, altitude and season. A retrieval code is developed combining an iterative inversion algorithm, working from top of the atmosphere downwards, and a parameterization of the variability of NO and NO{sub 2}. The method is used to examine the accuracy of the retrieval of the vertical concentration profiles and results show that the recovered profiles are in good agreement with measured ones, reflect the trends of NO and NO{sub 2} at sunset and sunrise and satisfy the accuracy expectations of the HALOE experiment.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Changes in the carbon dioxide expirogram in response to ozone exposure

    SciTech Connect

    Taylor, Adekemi B.; Lee, Genea M.; Nellore, Kavitha; Ben-Jebria, Abdellaziz . E-mail: axb23@psu.edu; Ultman, James S.

    2006-05-15

    The objectives of this study were to quantify pulmonary responses to ozone (O{sub 3}) exposure by parameters computed from the carbon dioxide expirogram and to compare these responses to decrements in forced expired spirometry. Anatomical dead space (V {sub D}) was determined from the pure dead space and transition regions of the expirogram. Four alternative parameters were computed from the alveolar plateau: slope (S), normalized slope (NS), peripheral cross-sectional area (A {sub P}) and well-mixed peripheral volume (V {sub MP}). Forty-seven healthy nonsmokers (25 men and 22 women) participated in two research sessions in which they exercised on a cycle ergometer for 1 h while orally inhaling either room air at a minute ventilation of 30.6 {+-} 3.6 L or room air mixed with 0.252 {+-} 0.029 ppm O{sub 3} at a minute ventilation of 29.9 {+-} 3.7 L. Carbon dioxide expirograms were measured before exposure, 10 min after exposure and 70 min after exposure. Percent changes (mean {+-} SD) in expirogram parameters were significant (P {<=} 0.002) at both 10 and 70 min after O{sub 3} exposure: V {sub D}(-4.2 {+-} 5.1, -3.3 {+-} 6.9), S(16.4 {+-} 17.9, +15.1 {+-} 20.2), NS(17.5 {+-} 15.4, +15.9 {+-} 19.2), A {sub P}(-8.1 {+-} 7.6, -7.7 {+-} 9.8) and V {sub MP}(-15.4 {+-} 13.0, -13.0 {+-} 15.2). Percent decrements of forced expired volume in one second (FEV{sub 1}) were also significant at both 10 min (-13.3 {+-} 13.4) and 70 min (-11.1 {+-} 9.2) following O{sub 3} exposure. Changes in the expirogram as well as decrements in FEV{sub 1} were not significant at either time point after air exposure. Thus, the CO{sub 2} expirogram is useful for characterizing the effect of O{sub 3} exposure on gas transport, and for supplementing forced expired spirometry that is frequently used to quantify lung mechanics.

  15. 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.

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

    SciTech Connect

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

    1983-01-01

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

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

    SciTech Connect

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

    1983-10-01

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

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

    PubMed

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

    2013-01-01

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

  19. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway.

    PubMed

    Shabbir, Yasir; Khokhar, Muhammad Fahim; Shaiganfar, Reza; Wagner, Thomas

    2016-05-01

    This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO2) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO2 revealed that the concentrations were higher within major cities along the highway. The highest NO2 vertical column densities (NO2 VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO2 VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.

  2. 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.

  3. Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway.

    PubMed

    Shabbir, Yasir; Khokhar, Muhammad Fahim; Shaiganfar, Reza; Wagner, Thomas

    2016-05-01

    This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO2) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO2 revealed that the concentrations were higher within major cities along the highway. The highest NO2 vertical column densities (NO2 VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO2 VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas. PMID:27155404

  4. Transport of carbon dioxide, water vapor, and ozone by turbulence and local circulations

    NASA Astrophysics Data System (ADS)

    Sun, Jielun; Desjardins, Raymond; Mahrt, Larry; MacPherson, Ian

    1998-10-01

    Nocturnal land breezes and daytime lake breezes are studied using data collected by the Canadian Twin Otter aircraft and a deck boat which traversed Candle Lake during the Boreal Ecosystem-Atmosphere Study (BOREAS). The nocturnal vertical transport of CO2, water vapor, and ozone over the lake consists of two parts: (1) mesoscale rising motion associated with land breeze convergence and (2) significant turbulence and vertical mixing driven by buoyancy in the lower part of the internal boundary layer and shear generation in the top part of the internal boundary layer. For comparison, the role of the lake in the daytime is examined in terms of formation of a stable internal boundary layer due to advection of warm air from land with small CO2 concentration over the cooler lake surface. Analysis of the aircraft and boat data indicates that the nocturnal land breeze plays an important role in the regional CO2 budget in the lake region. In the present study, CO2 is advected horizontally by a nocturnal land breeze circulation and vented vertically over Candle Lake ("chimney effect"). Such near-surface horizontal transport implies that part of the respirated CO2 never reaches the tower observational level, particularly under light wind conditions. This study speculates that preferred locations of vertical venting of CO2 may also occur due to convergence of nocturnal drainage circulations or flow meandering, although probably weaker than that associated with the land breeze. These circulations partly explain recent findings that tower-measured nocturnal turbulent fluxes of CO2 above the canopy and the subcanopy storage of CO2 frequently sum to less than the total respiration of CO2, leading to "missing CO2." Unfortunately, the present study does not allow evaluation of all of the terms in the carbon dioxide budget.

  5. 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}.

  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. Prior exposure to ozone potentiates subsequent response to sulfur dioxide in adolescent asthmatic subjects

    SciTech Connect

    Koenig, J.Q.; Covert, D.S.; Hanley, Q.S.; van Belle, G.; Pierson, W.E. )

    1990-02-01

    The objective of this study was to test whether prior exposure to a low concentration of ozone (120 ppb) would condition airways in asthmatic subjects to respond to a subthreshold concentration of sulfur dioxide (100 ppb). Eight male and five female subjects 12 to 18 yr of age participated. They all had allergic asthma and exercise-induced bronchospasm. Subjects were exposed to three test atmosphere sequences during intermittent moderate exercise (a 45-min exposure to one pollutant followed by a 15-min exposure to the second pollutant). The sequences were: air followed by 100 ppb SO2, 120 ppb O3 followed by 120 ppb O3, and 120 ppb O3 followed by 100 ppb SO2. The pulmonary function measurements assessed were FEV1, total respiratory resistance (RT), and maximal flow (Vmax50). Air-SO2 and O3-O3 exposures did not cause significant changes in pulmonary function. On the other hand, exposure to 100 ppb SO2 after a 45-min exposure to 120 ppb O3 caused a significant (8%) decrease in FEV1 (p = 0.046), a significant (19%) increase in RT (p = 0.048), and a significant (15%) decrease in Vmax50 (p = 0.008). It is concluded that prior O3 exposure increased bronchial hyperresponsiveness in these subjects such that they responded to an ordinarily subthreshold concentration of SO2. These data suggest that assessment of pulmonary changes to single pollutant challenges overlooks the interactive effects of common coexisting or sequentially occurring air pollutants.

  9. 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. PMID:25372614

  10. 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/.

  11. 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.

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

    PubMed

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

    2005-03-01

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

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

    SciTech Connect

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

    1989-11-01

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

  14. 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 ...

  15. 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.

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

    PubMed

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

    2003-12-01

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

  17. 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

    ... 1. Alternative A—Gas phase titration (GPT) of an NO standard with O3. Major equipment required... titration. A procedure for generating zero air is given in reference 13. 1.4 Dynamic parameter specification... Dioxide, and Ozone Analyzers by Gas Phase Titration,” EPA-R2-73-246, March 1974. 9. J. A. Hodgeson, R....

  18. 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

    ... 1. Alternative A—Gas phase titration (GPT) of an NO standard with O3. Major equipment required... titration. A procedure for generating zero air is given in reference 13. 1.4 Dynamic parameter specification... Dioxide, and Ozone Analyzers by Gas Phase Titration,” EPA-R2-73-246, March 1974. 9. J. A. Hodgeson, R....

  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, 2012 CFR

    2012-07-01

    ... 1. Alternative A—Gas phase titration (GPT) of an NO standard with O3. Major equipment required... titration. A procedure for generating zero air is given in reference 13. 1.4 Dynamic parameter specification... Dioxide, and Ozone Analyzers by Gas Phase Titration,” EPA-R2-73-246, March 1974. 9. J. A. Hodgeson, R....

  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, 2011 CFR

    2011-07-01

    ... 1. Alternative A—Gas phase titration (GPT) of an NO standard with O3. Major equipment required... titration. A procedure for generating zero air is given in reference 13. 1.4 Dynamic parameter specification... Dioxide, and Ozone Analyzers by Gas Phase Titration,” EPA-R2-73-246, March 1974. 9. J. A. Hodgeson, R....

  1. 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. PMID:26809503

  2. 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.

  3. Evaluating the uncertainties of thermal catalytic conversion in measuring atmospheric nitrogen dioxide at four differently polluted sites in China

    NASA Astrophysics Data System (ADS)

    Xu, Zheng; Wang, Tao; Xue, L. K.; Louie, Peter K. K.; Luk, Connie W. Y.; Gao, J.; Wang, S. L.; Chai, F. H.; Wang, W. X.

    2013-09-01

    A widely used method for measuring nitrogen dioxide (NO2) in the atmosphere is the conversion of NO2 to nitric oxide (NO) on the hot surface of a molybdenum oxide (MoO) catalyst followed by the chemiluminescence detection of NO. Although it has long been recognized that this type of conversion may suffer from the positive interference of other oxidized nitrogen compounds, evaluations of such interference in the atmosphere are scarce, thus rendering it difficult to make use of a large portion of the NO2 or NOx data obtained via this method (often denoted as NO2* or NOx*). In the present study, we compared the MoO converter with a selective, more accurate photolytic approach at four differently polluted sites in China. The converter worked well at the urban site, which was greatly affected by fresh emissions, but, on average, overestimated NO2 by 30%-50% at the two suburban sites and by more than 130% at the mountain-top site during afternoon hours, with a much larger positive bias seen during the top 10% of ozone events. The degree of overestimation depended on both air-parcel age and the composition of the oxidation products/intermediates of NOx (NOz). We attempted to derive an empirical formula to correct for this overestimation using concurrently measured O3, NO, and NO2* at the two suburban sites. Although the formula worked well at each individual site, the different NOz partitions at the sites made it difficult to obtain a universal formula. In view of the difficulty of assessing the uncertainties of the conventional conversion method, thus limiting the usability of data obtained via this method in atmospheric research, we suggest that, in areas away from fresh NOx emission sources, either a more selective NO2 measurement method or a NOy (NOx and its reaction products and intermediates) instrument should be adopted.

  4. The weekend effect within and downwind of Sacramento: Part 1. Observations of ozone, nitrogen oxides, and VOC reactivity

    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.

    2006-11-01

    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. This routine monitoring data is complemented by comprehensive data sets of ozone and nitrogen oxide concentrations and VOC reactivity obtained in the summers of 2001 and 2003 at three sites in the region. Daytime concentrations of nitrogen oxides (NOx) are approximately 35% lower on weekends at all the sites, whereas the VOC reactivity changes by less than 10%. All six sites in the Sacramento Valley have higher 8-h maximum average ozone on the weekend and are more likely to exceed the national standard of 85 ppb on the weekend. In contrast, all the sites in the Mountain Counties are less likely to exceed the federal ozone standard on the weekend. Analysis of the day-of-week trends in odd oxygen show that the weekend effect of ozone within Sacramento is strongly influenced by NO sources close to the monitoring sites. This suggests that ozone measurements from monitoring sites close to highways, including two rural locations, may not be representative of the regional abundance, and lead to underestimates of long term exposure for humans and ecosystems.

  5. 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

  6. 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

  7. 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.

  8. Nitrogen Oxides from Biogenic Alkyl Nitrates: A Natural Source of Tropospheric Ozone

    NASA Astrophysics Data System (ADS)

    Neu, J. L.; Lawler, M. J.; Saltzman, E. S.; Prather, M. J.

    2007-12-01

    Observations indicate that the tropical and southern oceans are source regions for biogenic emissions of alkyl nitrates. These compounds have lifetimes of several days to a month and are a significant source of reactive odd nitrogen (NOx) in remote regions of the atmosphere. These biogenically produced NOx precursors represent a natural control on atmospheric composition, including the important greenhouse gases methane (CH4) and tropospheric ozone (O3). We present simulations from the UCI global chemical transport model (CTM) using measurement-based fluxes of methyl and ethyl nitrate from their oceanic source regions and examine the contribution of these gases to global atmospheric composition. We also discuss the sensitivity of our results to our representation of two sub-gridscale processes: wet scavenging and photolysis in the presence of broken cloud fields. Quantification of the transport and chemistry of these compounds improves our understanding of natural tropospheric ozone production as well as hydroxyl radical (OH) chemistry in both the remote regions of the modern atmosphere and the pre-industrial atmosphere.

  9. 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.

  10. 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.

  11. 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.

  12. Indoor microclimate, ozone and nitrogen oxides in two medieval churches in Cyprus

    NASA Astrophysics Data System (ADS)

    Loupa, G.; Charpantidou, E.; Kioutsioukis, I.; Rapsomanikis, S.

    A number of indoor atmosphere parameters that may affect the preservation of artefacts in two churches in Cyprus, were studied. Temperature, relative humidity (RH), total ultra-violet and total solar radiation, that were continuously recorded during two campaigns (summer and winter), exhibited large diurnal and seasonal variations. Indoor concentrations of nitrogen oxides, determined at the same periods, also exhibited diurnal dependence on air exchange rate (AER) and on their indoor sources from the burning of candles and oil lamps. Indoor concentrations of ozone exhibited dependence on the AER and on the concentration of other indoor pollutants. On a large number of occasions these concentrations exceeded the proposed air quality standards for the preservation of works of art in both churches.

  13. 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.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-08-21

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-08-01

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

  18. 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.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-08-01

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

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

    PubMed

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

    2008-08-15

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

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

    PubMed

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

    2014-10-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    PubMed

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

    2013-03-01

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

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

    SciTech Connect

    Not Available

    1988-05-09

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

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

    PubMed

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

    2005-03-17

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

  8. Integration of continuous biofumigation with Muscodor albus with pre-cooling fumigation with ozone or sulfur dioxide to control postharvest gray mold of table grapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sulfur dioxide (SO2) fumigation controls postharvest decay of commercially stored table grapes. To develop an alternative to SO2, fumigation with up to 10,000 micro-l/l ozone (O3) for up to 2 h was applied to control postharvest gray mold caused by Botrytis cinerea. O3 was effective when grapes were...

  9. 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.

  10. Effects of acidic rain and ozone on nitrogen fixation and photosynthesis in the lichen lobaria pulmonaria (L. ) Hoffm

    SciTech Connect

    Sigal, L.L.; Johnston, J.W.

    1986-01-01

    The lichen Lobaria pulmonaria was subjected to ozone fumigations at 118, 235 and 353 mcg/cu m and simulated acidic rain at pH levels of 2.6, 4.2 and 5.6 for 5 days (M,W,F,M,W) during a 10-day period. Acidic rain at pH 2.6 caused significant reduction in nitrogen fixation and gross photosynthesis of 100 and 90%, respectively, and thallus bleaching was apparent. There were no significant differences between the pH 5.6 and 4.2 treatments in either gross photosynthesis or nitrogen fixation, and the color of the lichen thalli was unchanged. The effect of ozone on nitrogen fixation and photosynthesis over the range of concentrations used was not significant, but there was a trend toward reduced nitrogen fixation with increasing O/sub 3/ concentration. There were no significant ozone-acidic rain interactions. The threshold for response to rain acidity for L. pulmonaria lies between pH 2.6 and 4.2, and the acidity of wet deposition in parts of the United States may fall in the range.

  11. 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.

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

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1975-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-02-15

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

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

    PubMed

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

    2014-02-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  18. 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)

  19. 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.; Proffitt, M. H.; Fahey, D. W.; Kelly, K. K.; Webster, C. R.; May, R. D.; Baumgardner, D.; Dye, J. E.; Wilson, J. C.; Elkins, J. W.; Anderson, J. G.

    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.

  20. 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.

  1. 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...

  2. The weekend effect within and downwind of Sacramento - Part 1: Observations of ozone, nitrogen oxides, and VOC reactivity

    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.

    2007-10-01

    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. Measurements of non-methane hydrocarbons are available for the summers of 2001-2003 at three of these sites and NOx at six of these sites for the full time period. This routine monitoring data is complemented by data sets of ozone and nitrogen oxide concentrations obtained in the summers of 2001 and 2003 at three sites in the region and comprehensive measurements of VOC reactivity at two sites in 2001. Daytime concentrations of nitrogen oxides (NOx≡NO+NO2) are approximately 35% lower on weekends at all the sites, whereas the VOC reactivity changes by less than 10%. All six sites in the Sacramento Valley have higher 8-h maximum average ozone on the weekend and are more likely to exceed the national standard of 85 ppb on the weekend. In contrast, all the sites in the Mountain Counties are less likely to exceed the federal ozone standard on the weekend. Analysis of the day-of-week trends in odd oxygen show that the weekend effect of ozone within Sacramento is strongly influenced by NO sources close to the monitoring sites. This suggests that ozone measurements from monitoring sites close to highways, including two rural locations, may not be representative of the regional abundance, and lead to underestimates of long term exposure for humans and ecosystems.

  3. 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.

  4. 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.

  5. Ozone and carbon trioxide synthesis by low energy ion implantation onto solid carbon dioxide and implications to astrochemistry

    NASA Astrophysics Data System (ADS)

    Sivaraman, Bhalamurugan; Raja Sekhar, B. N.; Fulvio, Daniele; Hunniford, Adam; McCullough, Bob; Palumbo, Maria Elisabetta; Mason, Nigel

    2013-08-01

    Ion implantation experiments were carried out on amorphous (30 K) and crystalline (80 K) solid CO2 using both reactive (D+, H+) and non-reactive (He+) ions, simulating different irradiation environments on satellite and dust grain surfaces. Such ion irradiation synthesized several new species in the ice including ozone (O3), carbon trioxide (CO3), and carbon monoxide (CO) the main dissociation product of carbon dioxide. The yield of these products was found to be strongly dependent upon the ion used for irradiation and the sample temperature. Ion implantation changes the chemical composition of the ice with recorded infrared spectra clearly showing the coexistence of D3h and C2v isomers of CO3, for the first time, in ion irradiated CO2 ice.

  6. 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

    2016-05-01

    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.

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

    PubMed

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

    2005-11-01

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

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

    SciTech Connect

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

    2009-12-01

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

  9. 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.

  10. Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation.

    PubMed

    Zoeteman, B C; Hrubec, J; de Greef, E; Kool, H J

    1982-12-01

    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.

  11. 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.

  12. 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. PMID:27215985

  13. 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.

  14. 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

  15. 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

  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. PMID:22097568

  17. 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.

  18. 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.

  19. Nitrogen origins and the role of ozonation in the formation of haloacetonitriles and halonitromethanes in chlorine water treatment.

    PubMed

    Yang, Xin; Shang, Chii; Shen, Qianqian; Chen, Baiyang; Westerhoff, Paul; Peng, Jinfeng; Guo, Wanhong

    2012-12-01

    Nitrogenous disinfection byproducts (N-DBPs) such as haloacetonitriles (HANs) and halonitromethanes (HNMs) are formed during water chlorination. Preozonation is sometimes applied to control trihalomethane (THM) formation, but this may risk promoting the formation of HNMs and HANs. The role of ozone in the formation of HANs and HNMs in natural waters remains unclear. The nitrogen sources involved in HAN and HNM formation during the chloramination of dissolved organic matter (DOM) with and without preozonation were evaluated using (15)N-labeled monochloramine. The origin of the nitrogen involved in HAN formation was found to depend on the ratio of dissolved organic carbon to nitrogen. In nitrogen-rich solutions HAN nitrogen was mainly from DOM constituents. The formation of (15)N-labeled dichloroacetontrile (DCAN) accounted for approximately 30% of the DCAN produced from all hydrophilic acidic and neutral isolates, which have low carbon to nitrogen ratios, while it reached over 50% for the hydrophobic acidic, basic, and neutral isolates with high carbon to nitrogen ratios. Unlabeled trichloronitromethane (TCNM) accounted for over 90% of the total TCNM produced from most of the isolates. The remaining less than 10% of the TCNM was probably generated through an aldehyde pathway. Preozonation reduced DCAN but enhanced the yield of TCNM. The destruction of amino acids and amine structures and subsequent formation of nitro groups by preozonation may help explain the reduced DCAN and increased TCNM formation. PMID:23153098

  20. 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.

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

    PubMed

    Hunsaker, Carolyn; Bytnerowicz, Andrzej; Auman, Jessica; Cisneros, Ricardo

    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 deposition levels, as well as studies focused on understanding effects mechanisms, are essential for evaluation of risks associated with their presence. Such information is essential for development of proper management strategies for maintaining clean air, clean water, and healthy ecosystems on land managed by the Forest Service. We report on two years of research in the central Sierra Nevada of California, a semi-arid forest at elevations of 1100-2700 m. Information on O3 and N air pollutants is obtained from a network of 18 passive samplers. We relate the atmospheric N concentration to N concentrations in streams, shallow soil water, and bulk deposition collectors within the Kings River Experimental Watershed. This watershed also contains an intensive site that is part of a recent Forest Service effort to calculate critical loads for N, sulfur, and acidity to forest ecosystems. The passive sampler design allows for extensive spatial measurements while the watershed experiment provides intensive spatial data for future analysis of ecosystem processes. PMID:17450299

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

    PubMed

    Hunsaker, Carolyn; Bytnerowicz, Andrzej; Auman, Jessica; Cisneros, Ricardo

    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 deposition levels, as well as studies focused on understanding effects mechanisms, are essential for evaluation of risks associated with their presence. Such information is essential for development of proper management strategies for maintaining clean air, clean water, and healthy ecosystems on land managed by the Forest Service. We report on two years of research in the central Sierra Nevada of California, a semi-arid forest at elevations of 1100-2700 m. Information on O3 and N air pollutants is obtained from a network of 18 passive samplers. We relate the atmospheric N concentration to N concentrations in streams, shallow soil water, and bulk deposition collectors within the Kings River Experimental Watershed. This watershed also contains an intensive site that is part of a recent Forest Service effort to calculate critical loads for N, sulfur, and acidity to forest ecosystems. The passive sampler design allows for extensive spatial measurements while the watershed experiment provides intensive spatial data for future analysis of ecosystem processes.

  3. 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

  4. 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).

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

    PubMed

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

    2013-09-01

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

  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. 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.

  8. 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%).

  9. 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.

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

    SciTech Connect

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

    1987-10-01

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

  11. 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

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

    PubMed

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

    2008-01-01

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

  13. 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...

  14. 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...

  15. 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: (...

  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, 2013 CFR

    2013-07-01

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

  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. 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

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

    PubMed

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

    2006-09-01

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

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

    PubMed

    Prescher, K E

    1982-01-01

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

  1. Chemical Data Assimilation Estimates of Continental US Ozone and Nitrogen Budgets during INTEX-A

    NASA Technical Reports Server (NTRS)

    Pierce, Robert B.; Schaack, Todd K.; Al-Saadi, Jassim A.; Fairlie, T. Duncan; Kittaka, Chieko; Lingenfelser, Gretchen; Natarajan, Murali; Olson, Jennifer; Soja, Amber; Zapotocny, Tom; Lenzen, Allen; Stobie, James; Johnson, Donald; Avery, Melody A.; Sachse, Glen W.; Thompson, Anne; Cohen, Ron; Dibb, Jack E.; Crawford, James H.; Rault, Didier F.; Martin, Randall; Szykman, James J.; Fishman, Jack

    2007-01-01

    Global ozone analyses, based on assimilation of stratospheric profile and ozone column measurements, and NOy predictions from the Real-time Air Quality Modeling System (RAQMS) are used to estimate the ozone and NOy budget over the Continental US during the July-August 2004 Intercontinental Chemical Transport Experiment-North America (INTEX-A). Comparison with aircraft, satellite, surface, and ozonesonde measurements collected during the INTEX-A show that RAQMS captures the main features of the global and Continental US distribution of tropospheric ozone, carbon monoxide, and NOy with reasonable fidelity. Assimilation of stratospheric profile and column ozone measurements is shown to have a positive impact on the RAQMS upper tropospheric/lower stratosphere ozone analyses, particularly during the period when SAGE III limb scattering measurements were available. Eulerian ozone and NOy budgets during INTEX-A show that the majority of the Continental US export occurs in the upper troposphere/lower stratosphere poleward of the tropopause break, a consequence of convergence of tropospheric and stratospheric air in this region. Continental US photochemically produced ozone was found to be a minor component of the total ozone export, which was dominated by stratospheric ozone during INTEX-A. The unusually low photochemical ozone export is attributed to anomalously cold surface temperatures during the latter half of the INTEX-A mission, which resulted in net ozone loss during the first 2 weeks of August. Eulerian NOy budgets are shown to be very consistent with previously published estimates. The NOy export efficiency was estimated to be 24 percent, with NOx+PAN accounting for 54 percent of the total NOy export during INTEX-A.

  2. An investigation of evapotranspiration rates within mid-western agricultural systems in response to elevated carbon dioxide and ozone concentrations and climate change

    NASA Astrophysics Data System (ADS)

    Abdullah, W. F.; Lombardozzi, D.; Levis, S.; Bonan, G. B.

    2013-12-01

    Warith Featherstone Abdullah, Danica Lombardozzi, Samuel Levis and Gordon Bonan Jackson State University Dept. of Physics, Atmospheric Sciences & Geosciences National Center for Atmospheric Research Climate & Global Dynamics Because the human population is expected to surpass 8 billion by the year 2050, food security is a pressing issue. In the face of elevated temperatures associated with climate change (CC), elevated carbon dioxide (CO2) and elevated ozone (O3) concentrations, food productivity is uncertain. Plant stomata must be open to gain carbon which simultaneously causes water loss. Research suggests rising temperatures, elevated CO2 and elevated O3 in the future may impact plant stomata and change the rate plants lose water and take up carbon, affecting plant productivity and crop yields. Evapotranspiration (ET), latent heat fluxes, leaf carbon and net primary productivity (NPP) were analyzed in U.S Mid-west where crop density is greatest. Four simulations were run using the National Center for Atmospheric Research (NCAR) Community Land Model version 4 (CLM4) component of the Community Earth System Model (CESM) with an extended carbon-nitrogen model (CN). Analyses were based on June-July-August seasonal averages through 2080-2100 to compare the individual effects of CC, elevated CO2 and O3, and combined effects of all drivers. Results from model projections show increased ET with CC and all drivers combined, but only small changes from O3 or CO2 alone. Further results show that NPP was reduced with CC and O3 alone, but increased with CO2 alone and only slightly reduced with interacting components. The combined driver simulation, which most accurately represents future global change, suggests deteriorating water usage efficiency, thus potentially decreasing carbon uptake and crop production. However, further research is needed for verification. Midwest seasonal summation estimates for net primary productivity calculated by CLM4CN model. Climate change, CO2

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Shu, John Hungjen

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    SciTech Connect

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

    2014-09-29

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    PubMed

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-06-19

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

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

    PubMed

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-01-01

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

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

    PubMed Central

    Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

    2015-01-01

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

  12. Heterogeneous responses to ozone and nitrogen alter the species composition of Mediterranean annual pastures.

    PubMed

    Calvete-Sogo, H; González-Fernández, I; Sanz, J; Elvira, S; Alonso, R; García-Gómez, H; Ibáñez-Ruiz, M A; Bermejo-Bermejo, V

    2016-08-01

    Air pollution represents a threat to biodiversity throughout the world and particularly in the Mediterranean area, where high tropospheric ozone (O3) concentrations and atmospheric nitrogen (N) deposition are frequently recorded. Mediterranean annual pastures are among the most important ecosystems in southern Europe due to their high biodiversity and extension. Aiming to study the responses of these communities to the main atmospheric pollutants in the Mediterranean region, an experimental study was performed in an open-top chamber (OTC) facility. A mixture of six species representative of annual pastures was grown under field conditions inside the OTC. Plants were exposed for 39 days to four O3 treatments and three doses of N. The species responded heterogeneously to both factors. Legumes did not react to N but were very sensitive to O3: Trifolium species responded negatively, while Ornithopus responded positively, taking advantage of the greater sensitivity of clovers to O3. The grasses and the herb were more tolerant of O3 and grasses were the most responsive to N. Significant interactions between factors indicated a loss of effectiveness of N in O3-polluted atmospheres and an ability of O3 to counterbalance the damage induced by N input, but both effects were dependent on O3 and N levels. The inclusion of plant competition in the experimental design was necessary to reveal results that would otherwise be missed, such as the positive growth responses under elevated O3 levels. Surprisingly, competition within the legume family played the most important role in the overall response of the annual community to O3. Both tropospheric O3 and N deposition should be considered important drivers of the structure and biodiversity of Mediterranean annual pastures.

  13. Dynamics of nitrogen oxides and ozone above and within a mixed hardwood forest in Northern Michigan

    NASA Astrophysics Data System (ADS)

    Seok, B.; Helmig, D.; Ganzeveld, L.; Williams, M. W.; Vogel, C. S.

    2012-12-01

    The dynamic behavior of nitrogen oxides (NOx = NO + NO2) and ozone (O3) above and within the canopy at the University of Michigan Biological Station AmeriFlux (UMBS Flux) site was investigated by continuous multi-height vertical gradient measurements during the summer and the fall of 2008. A daily maximum in nitric oxide (NO) levels was consistently observed during the morning hours between 06:00 and 09:00 EST above the canopy. Daily NO maxima ranged between 0.2 and 2 ppbv (with a median of 0.3 ppbv), which was 2 to 20 times above its atmospheric background. The sources and causes of this NO maximum were evaluated using NOx and O3 measurements and synoptic and micrometeorological data. This analysis was further supported by numerical simulations with a multi-layer canopy exchange model implemented into a single-column chemistry-climate model. The observations indicated that the morning NO maximum was caused by the photolysis of NO2 from non-local air masses, which were transported into the canopy from aloft during the morning breakup of the nocturnal boundary layer. The analysis of simulated process tendencies indicated that the downward turbulent transport of NOx into the canopy compensates for the removal of NOx through chemistry and dry deposition. The sensitivity of NOx and O3 concentrations on soil and foliage NOx emissions was also assessed with the model. Uncertainties associated with the emissions of NOx from the soil or from leaf-surface nitrate photolysis did not explain the observed diurnal behavior in NOx (and O3), and in particular, the morning NOx peak mixing ratio. However, when considering the existence of a NO2 compensation point, an increase in the early morning NOx and NO peak mixing ratios by ~30% was simulated. This increase suggests the potential importance of leaf-level, bi-directional exchange of NO2 in understanding the observed temporal variability in NOx at UMBS.

  14. Dynamics of nitrogen oxides and ozone above and within a mixed hardwood forest in northern Michigan

    NASA Astrophysics Data System (ADS)

    Seok, B.; Helmig, D.; Ganzeveld, L.; Williams, M. W.; Vogel, C. S.

    2013-08-01

    The dynamic behavior of nitrogen oxides (NOx = NO + NO2) and ozone (O3) above and within the canopy at the University of Michigan Biological Station AmeriFlux (UMBS Flux) site was investigated by continuous multi-height vertical gradient measurements during the summer and the fall of 2008. A daily maximum in nitric oxide (NO) mixing ratios was consistently observed during the morning hours between 06:00 and 09:00 EST above the canopy. Daily NO maxima ranged between 0.1 and 2 ppbv (with a median of 0.3 ppbv), which were 2 to 20 times above the atmospheric background. The sources and causes of the morning NO maximum were evaluated using NOx and O3 measurements and synoptic and micrometeorological data. Numerical simulations with a multi-layer canopy-exchange model were done to further support this analysis. The observations indicated that the morning NO maximum was caused by the photolysis of NO2 from non-local air masses, which were transported into the canopy from aloft during the morning breakup of the nocturnal boundary layer. The analysis of simulated process tendencies indicated that the downward turbulent transport of NOx into the canopy compensates for the removal of NOx through chemistry and dry deposition. The sensitivity of NOx and O3 concentrations to soil and foliage NOx emissions was also assessed with the model. Uncertainties associated with the emissions of NOx from the soil or from leaf-surface nitrate photolysis did not explain the observed diurnal behavior in NOx (and O3) and, in particular, the morning peak in NOx mixing ratios. However, a ~30% increase in early morning NOx and NO peak mixing ratios was simulated when a foliage exchange NO2 compensation point was considered. This increase suggests the potential importance of leaf-level, bidirectional exchange of NO2 in understanding the observed temporal variability in NOx at UMBS.

  15. Heterogeneous responses to ozone and nitrogen alter the species composition of Mediterranean annual pastures.

    PubMed

    Calvete-Sogo, H; González-Fernández, I; Sanz, J; Elvira, S; Alonso, R; García-Gómez, H; Ibáñez-Ruiz, M A; Bermejo-Bermejo, V

    2016-08-01

    Air pollution represents a threat to biodiversity throughout the world and particularly in the Mediterranean area, where high tropospheric ozone (O3) concentrations and atmospheric nitrogen (N) deposition are frequently recorded. Mediterranean annual pastures are among the most important ecosystems in southern Europe due to their high biodiversity and extension. Aiming to study the responses of these communities to the main atmospheric pollutants in the Mediterranean region, an experimental study was performed in an open-top chamber (OTC) facility. A mixture of six species representative of annual pastures was grown under field conditions inside the OTC. Plants were exposed for 39 days to four O3 treatments and three doses of N. The species responded heterogeneously to both factors. Legumes did not react to N but were very sensitive to O3: Trifolium species responded negatively, while Ornithopus responded positively, taking advantage of the greater sensitivity of clovers to O3. The grasses and the herb were more tolerant of O3 and grasses were the most responsive to N. Significant interactions between factors indicated a loss of effectiveness of N in O3-polluted atmospheres and an ability of O3 to counterbalance the damage induced by N input, but both effects were dependent on O3 and N levels. The inclusion of plant competition in the experimental design was necessary to reveal results that would otherwise be missed, such as the positive growth responses under elevated O3 levels. Surprisingly, competition within the legume family played the most important role in the overall response of the annual community to O3. Both tropospheric O3 and N deposition should be considered important drivers of the structure and biodiversity of Mediterranean annual pastures. PMID:27106851

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

    PubMed

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

    2009-10-01

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

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

    PubMed

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

    2002-01-01

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

  18. Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

    DOE PAGES

    Lu, Z.; Streets, D. G.; de Foy, B.; Lamsal, L. N.; Duncan, B. N.; Xing, J.

    2015-05-28

    Satellite remote sensing of tropospheric nitrogen dioxide (NO2) can provide valuable information for estimating surface nitrogen oxides (NOx) emissions. Using an exponentially-modified Gaussian (EMG) method and taking into account the effect of wind on observed NO2 distributions, we estimate three-year moving-average emissions of summertime NOx from 35 US urban areas directly from NO2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005–2014. Following the conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NOx emissions from each urban area by applying the EMG method to OMI data with windmore » speeds greater than 3–5 m s-1. Meanwhile, we find that OMI NO2 observations under weak-wind conditions (i.e., < 3 m s-1) are qualitatively better correlated with the surface NOx source strength in comparison to all-wind OMI maps; and therefore we use them to calculate the satellite-observed NO2 burdens of urban areas and compare with NOx emission estimates. The EMG results show that OMI-derived NOx emissions are highly correlated (R > 0.93) with weak-wind OMI NO2 burdens as well as bottom-up NOx emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous, EMG-obtained, effective NO2 lifetimes (~3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO2 chemical lifetimes. In general, isolated urban areas with NOx emission intensities greater than ~ 2 Mg h-1 produce statistically significant weak-wind signals in three-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NOx emissions over all selected US urban areas decreased by 49%, consistent with reductions of 43, 47, 49, and 44% in the total bottom-up NOx emissions, the sum of weak-wind OMI NO2 columns, the total weak-wind OMI NO2 burdens, and the averaged NO2 concentrations

  19. Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Streets, D. G.; de Foy, B.; Lamsal, L. N.; Duncan, B. N.; Xing, J.

    2015-05-01

    Satellite remote sensing of tropospheric nitrogen dioxide (NO2) can provide valuable information for estimating surface nitrogen oxides (NOx) emissions. Using an exponentially-modified Gaussian (EMG) method and taking into account the effect of wind on observed NO2 distributions, we estimate three-year moving-average emissions of summertime NOx from 35 US urban areas directly from NO2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005-2014. Following the conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NOx emissions from each urban area by applying the EMG method to OMI data with wind speeds greater than 3-5 m s-1. Meanwhile, we find that OMI NO2 observations under weak-wind conditions (i.e., < 3 m s-1) are qualitatively better correlated with the surface NOx source strength in comparison to all-wind OMI maps; and therefore we use them to calculate the satellite-observed NO2 burdens of urban areas and compare with NOx emission estimates. The EMG results show that OMI-derived NOx emissions are highly correlated (R > 0.93) with weak-wind OMI NO2 burdens as well as bottom-up NOx emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous, EMG-obtained, effective NO2 lifetimes (~3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO2 chemical lifetimes. In general, isolated urban areas with NOx emission intensities greater than ~ 2 Mg h-1 produce statistically significant weak-wind signals in three-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NOx emissions over all selected US urban areas decreased by 49%, consistent with reductions of 43, 47, 49, and 44% in the total bottom-up NOx emissions, the sum of weak-wind OMI NO2 columns, the total weak-wind OMI NO2 burdens, and the averaged NO2 concentrations

  20. Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Streets, D. G.; de Foy, B.; Lamsal, L. N.; Duncan, B. N.; Xing, J.

    2015-09-01

    Satellite remote sensing of tropospheric nitrogen dioxide (NO2) can provide valuable information for estimating surface nitrogen oxides (NOx) emissions. Using an exponentially modified Gaussian (EMG) method and taking into account the effect of wind on observed NO2 distributions, we estimate 3-year moving-average emissions of summertime NOx from 35 US (United States) urban areas directly from NO2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005-2014. Following conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NOx emissions from each urban area by applying the EMG method to OMI data with wind speeds greater than 3-5 m s-1. Meanwhile, we find that OMI NO2 observations under weak-wind conditions (i.e., < 3 m s-1) are qualitatively better correlated to the surface NOx source strength in comparison to all-wind OMI maps; therefore, we use them to calculate the satellite-observed NO2 burdens of urban areas and compare with NOx emission estimates. The EMG results show that OMI-derived NOx emissions are highly correlated (R > 0.93) with weak-wind OMI NO2 burdens as well as with bottom-up NOx emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous EMG-obtained effective NO2 lifetimes (~ 3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO2 chemical lifetimes. In general, isolated urban areas with NOx emission intensities greater than ~ 2 Mg h-1 produce statistically significant weak-wind signals in 3-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NOx emissions over all selected US urban areas decreased by 49 %, consistent with reductions of 43, 47, 49, and 44 % in the total bottom-up NOx emissions, the sum of weak-wind OMI NO2 columns, the total weak-wind OMI NO2 burdens, and the averaged NO2 concentrations

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

    NASA Astrophysics Data System (ADS)

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

    1980-08-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    1981-08-01

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

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

    PubMed

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

    2009-01-01

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

  6. Discharge cell for ozone generator

    DOEpatents

    Nakatsuka, Suguru

    2000-01-01

    A discharge cell for use in an ozone generator is provided which can suppress a time-related reduction in ozone concentration without adding a catalytic gas such as nitrogen gas to oxygen gas as a raw material gas. The discharge cell includes a pair of electrodes disposed in an opposed spaced relation with a discharge space therebetween, and a dielectric layer of a three-layer structure consisting of three ceramic dielectric layers successively stacked on at least one of the electrodes, wherein a first dielectric layer of the dielectric layer contacting the one electrode contains no titanium dioxide, wherein a second dielectric layer of the dielectric layer exposed to the discharge space contains titanium dioxide in a metal element ratio of not lower than 10 wt %.

  7. Utilization of a Response-Surface Technique in the Study of Plant Responses to Ozone and Sulfur Dioxide Mixtures 1

    PubMed Central

    Ormrod, Douglas P.; Tingey, David T.; Gumpertz, Marcia L.; Olszyk, David M.

    1984-01-01

    A second order rotatable design was used to obtain polynomial equations describing the effects of combinations of sulfur dioxide (SO2) and ozone (O3) on foliar injury and plant growth. The response surfaces derived from these equations were displayed as contour or isometric (3-dimensional) plots. The contour plots aided in the interpretation of the pollutant interactions and were judged easier to use than the isometric plots. Plants of `Grand Rapids' lettuce (Lactuca sativa L.), `Cherry Belle' radish (Raphanus sativus L.), and `Alsweet' pea (Pisum sativum L.) were grown in a controlled environment chamber and exposed to seven combinations of SO2 and O3. Injury was evaluated based on visible chlorosis and necrosis and growth was evaluated as leaf area and dry weight. Covariate measurements were used to increase precision. Radish and pea had greater injury, in general, that did lettuce; all three species were sensitive to O3, and pea was most sensitive and radish least sensitive to SO2. Leaf injury responses were relatively more affected by the pollutants than were plant growth responses in radish and pea but not in lettuce. In radish, hypocotyl growth was more sensitive to the pollutants than was leaf growth. PMID:16663598

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2015-10-01

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

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

    PubMed

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

    2015-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  14. CANOZE measurements of the Arctic ozone hole

    NASA Technical Reports Server (NTRS)

    Evans, W. F. J.; Kerr, J. B.; Fast, H.

    1988-01-01

    In CANOZE 1 (Canadian Ozone Experiment), a series of 20 ozone profile measurements were made in April, 1986 from Alert at 82.5 N. CANOZE is the Canadian program for study of the Arctic winter ozone layer. In CANOZE 2, ozone profile measurements were made at Saskatoon, Edmonton, Churchill and Resolute during February and March, 1987 with ECC ozonesondes. Ground based measurements of column ozone, nitrogen dioxide and hydrochloric acid were conducted at Saskatoon. Two STRATOPROBE balloon flights were conducted on February 26 and March 19, 1987. Two aerosol flights were conducted by the University of Wyoming. The overall results of this study will be reported and compared with the NOZE findings. The results from CANOZE 3 in 1988, are also discussed. In 1988, as part of CANOZE 3, STRATOPROBE balloon flights were conducted from Saskatchewan on January 27 and February 13. A new lightweight infrared instrument was developed and test flown. A science flight was successfully conducted from Alert (82.5 N) on March 9, 1988 when the vortex was close to Alert; a good measurement of the profile of nitric acid was obtained. Overall, the Arctic spring ozone layer exhibits many of the features of the Antarctic ozone phenomenon, although there is obviously not a hole present every year. The Arctic ozone field in March, 1986 demonstrated many similarities to the Antarctic ozone hole. The TOMS imagery showed a crater structure in the ozone field similar to the Antarctic crater in October. Depleted layers of ozone were found in the profiles around 15 km, very similar to those reported from McMurdo. Enhanced levels of nitric acid were measured in air which had earlier been in the vortex. The TOMS imagery for March 1987 did not show an ozone crater, but will be examined for an ozone crater in February and March, 1988, the target date for the CANOZE 3 project.

  15. Deposition and Effects of Atmospheric Nitrogen and Ozone in Holm Oak Forests in Spain

    NASA Astrophysics Data System (ADS)

    González Fernández, I.; García Gómez, H.; Calvete Sogo, H.; Bermejo, V.; Valiño, F.; Elvira, S.; Rábago, I.; Sanz, J.; Alonso, R.

    2013-12-01

    Atmospheric nitrogen (N) emissions in Spain, in the western Mediterranean basin, have followed an increasing trend since 1990 and have only started to decline recently. These trends have resulted in growing N depositions in some areas and in N enrichment of ecosystems, as described in previous studies by increasing records of nitrophilous species in herbaria and raising N content both in bryophytes and in leaves of forest trees. Tropospheric ozone (O3) background concentrations, formed as a result of photochemical reactions of N compounds in the atmosphere, have also increased during the last decades. Despite these evidences, limited information is available on N and O3 deposition and effects in Holm oak forests, important ecosystems in Spain. New studies are being developed to address this lack of data. First results on N deposition in a Holm oak forest in central Spain stress the importance of seasonal variations of N inputs in Mediterranean environments. Spring and autumn rainfall events added up to 80% of total annual bulk deposition and losses of NO3- in the soil water were detected when throughfall N pulses occurred during periods of low plant physiological activity. N uptake in the tree canopy was also observed. High O3 concentrations were also measured in this study. The exposure to both N and O3 is a common situation in Holm oak forests. The combined effect of N and O3 deposition on the annual pasture of the Holm oak forest understory has been studied in an open-top chamber study using a simplified community of six species. Results show that O3 can potentially reduce pasture growth, decrease its nutritive value for herbivores and cause shifts in species abundance. N deposition can partially counterbalance O3-induced effects on the pasture biomass, thus both O3 and N need to be considered together when studying air pollution impacts in these ecosystems. The studies presented here are intended for developing N and O3 critical loads and levels for the

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed

    Cheng, Andrew Y S; Chan, M H

    2004-12-01

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

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

    SciTech Connect

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

    1999-10-01

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

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

    SciTech Connect

    Wendel, G.J.

    1985-01-01

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

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

    PubMed

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

    2014-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2013-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    PubMed

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

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

    SciTech Connect

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

    1982-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed

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

    2001-01-01

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

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

    PubMed

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

    1998-06-01

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

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

    PubMed

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

    2015-11-01

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

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

    SciTech Connect

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

    2010-06-01

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-07-30

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

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  17. Seasonal variation of nitrogen oxides, ozone and biogenic volatile organic compound concentrations and fluxes at Norway spruce forest

    NASA Astrophysics Data System (ADS)

    Juran, Stanislav; Vecerova, Kristyna; Holisova, Petra; Zapletal, Milos; Pallozzi, Emanuele; Guidolotti, Gabriele; Calfapietra, Carlo; Vecera, Zbynek; Cudlin, Pavel; Urban, Otmar

    2015-04-01

    Dynamics of nitrogen oxides (NOx) and ozone concentration and their depositions were investigated on the Norway spruce forest at Bily Kriz experimental station at the Silesian Beskydy Mountains (north-eastern part of the Czech Republic). Both NOx and ozone concentration and fluxes were modelled for the whole season and covering thus different climate conditions. Data were recorded for three consecutive years and therefore deeper analyses were performed. During the summer 2014 BVOC field campaign was carried out using proton-transfer-reaction-time-of-flight-mass-spectrometry (PTR-TOF, Ionicon Analytik GmbH, Innsbruck, Austria) and volatile organic compound of biogenic origin (BVOC) were measured at the different levels of tree canopies. By the same time BVOC were trapped into the Tenax tubes (Markes International Ltd., UK) and put afterwards for thermal desorption (Markes Unity System 2, Markes International Ltd., UK) to GS-MS analysis (TSQ Quntum XLS triple Quadrupole, Thermo Scientific, USA). Thus data of different levels of canopies together with different spectra of monoterpenes were obtained. Interesting comparison of both methods will be shown. It was the first BVOC field campaign using PTR technique at any of the forest in the Czech Republic. Highest fluxes and concentrations were recorded around the noon hours, represented particularly by monoterpenes, especially α-pinen and limonene. Other BVOCs than monoterpenes were negligible. Variation of fluxes between different canopies levels was observed, highlighting difference in shaded and sun exposed leaves. Sun leaves emitted up to 2.4 nmol m-2 s-1 of monoterpenes, while shaded leaves emitted only up to 0.6 nmol m-2 s-1 when measured under standard conditions (irradiance 1000 µmol m-2 s-1; temperature 30°C). We discuss here the importance of the most common Norway spruce tree forests in the Czech Republic in bi-directional exchanges of important secondary pollutant such as ozone and nitrogen oxides, their

  18. Current ozone levels threaten gross primary production and yield of Mediterranean annual pastures and nitrogen modulates the response

    NASA Astrophysics Data System (ADS)

    Calvete-Sogo, Héctor; Elvira, Susana; Sanz, Javier; González-Fernández, Ignacio; García-Gómez, Héctor; Sánchez-Martín, Laura; Alonso, Rocío; Bermejo-Bermejo, Victoria

    2014-10-01

    Pastures are among the most important ecosystems in Europe considering their biodiversity and distribution area. However, their response to increasing tropospheric ozone (O3) and nitrogen (N) deposition, two of the main drivers of global change, is still uncertain. A new Open-Top Chamber (OTC) experiment was performed in central Spain, aiming to study annual pasture response to O3 and N in close to natural growing conditions. A mixture of six species of three representative families was sowed in the field. Plants were exposed for 40 days to four O3 treatments: filtered air, non-filtered air (NFA) reproducing ambient levels and NFA supplemented with 20 and 40 nl l-1 O3. Three N treatments were considered to reach the N integrated doses of “background”, +20 or +40 kg N ha-1. Ozone significantly reduced green and total aboveground biomass (maximum reduction 25%) and increased the senescent biomass (maximum increase 40%). Accordingly, O3 decreased community Gross Primary Production due to both a global reduction of ecosystem CO2 exchange and an increase of ecosystem respiration. Nitrogen could partially counterbalance O3 effects on aboveground biomass when the levels of O3 were moderate, but at the same time O3 exposure reduced the fertilization effect of higher N availability. Therefore, O3 must be considered as a stress factor for annual pastures in the Mediterranean areas.

  19. Ozone-biological activated carbon integrated treatment for removal of precursors of halogenated nitrogenous disinfection by-products.

    PubMed

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Deng, Yang; Templeton, Michael R

    2012-03-01

    Pilot-scale tests were performed to reduce the formation of several nitrogenous and carbonaceous disinfection by-products (DBPs) with an integrated ozone and biological activated carbon (O(3)-BAC) treatment process following conventional water treatment processes (coagulation-sedimentation-filtration). Relative to the conventional processes alone, O(3)-BAC significantly improved the removal of turbidity, dissolved organic carbon, UV(254), NH(4)(+) and dissolved organic nitrogen from 98-99%, 58-72%, 31-53%, 16-93% and 35-74%, respectively, and enhanced the removal efficiency of the precursors for the measured DBPs. The conventional process was almost ineffective in removing the precursors of trichloronitromethane (TCNM) and dichloroacetamide (DCAcAm). Ozonation could not substantially reduce the formation of DCAcAm, and actually increased the formation potential of TCNM; it chemically altered the molecular structures of the precursors and increased the biodegradability of N-containing organic compounds. Consequently, the subsequent BAC filtration substantially reduced the formation of the both TCNM and DCAcAm, thus highlighting a synergistic effect of O(3) and BAC. Additionally, O(3)-BAC was effective at controlling the formation of the total organic halogen, which can be considered as an indicator of the formation of unidentified DBPs.

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

    SciTech Connect

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

    1993-05-01

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

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

    SciTech Connect

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    PubMed Central

    Baltrusaitis, Jonas; Chen, Haihan; Rubasinghege, Gayan

    2012-01-01

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

  4. Interference of sulphur dioxide to balloon-borne ECC ozone sensors over the Valley of Mexico

    NASA Astrophysics Data System (ADS)

    Kanda, I.; Basaldud, R.; Horikoshi, N.; Okazaki, Y.; Benítez Garcia, S. E.; Ortínez, A.; Ramos Benítez, V. R.; Cárdenas, B.; Wakamatsu, S.

    2014-01-01

    Abnormal decrease in the ozonesonde sensor signal occurred during air-pollution study campaigns in November 2011 and March 2012 in Mexico City. Sharp drops around 5 km a.s.l. and above were observed in November 2011, and a broad deficit in the convective boundary layer in March 2012. Various circumstantial evidence indicates that the decrease was due to interference of SO2 gas to Electrochemical Concentration Cell (ECC) ozone sensors. The sharp drops in November 2011 are considered to be caused by the SO2 plume from the Popocatépetl volcano to the south-east of Mexico City. Response experiments of the ECC sensor to representative atmospheric trace gases showed that only SO2 could generate the observed abrupt drops. The vertical structure of the plume reproduced by a Lagrangian particle diffusion simulation also supported this assumption. The near-ground deficit in March 2012 is considered to be generated by the SO2 plume from the Tula industrial complex to the north-west of Mexico City. Sporadic large SO2 emission is known to occur from this region, and before and at the ozonesonde launching time, large intermittent peaks of SO2 concentration were recorded at the ground-level monitoring stations. The difference between the O3 concentration obtained by ozonesonde and that by UV-based O3 monitor was consistent with the SO2 concentration measured by a UV-based monitor on the ground. The plume vertical profiles estimated by the Lagrangian particle diffusion simulation agreed fairly well with the observed profile. Statistical analysis of the wind field in Mexico City revealed that the Popocatépetl effect is most likely to occur from June to October, and the Tula effect all the year.

  5. Nitrogen oxides from high-altitude aircraft - An update of potential effects on ozone

    NASA Technical Reports Server (NTRS)

    Johnston, Harold S.; Kinnison, Douglas E.; Wuebbles, Donald J.

    1989-01-01

    In the study of fuel consumption rate by stratospheric aircraft, the range of nitric oxide injection is interpreted as an eightfold range of emission index (5-40) with both the one- and the two-dimensional models. Possible effects of future aircraft NO(x) emissions on stratospheric ozone are considered for a broad range in magnitude, altitude, and latitude of the assumed NO(x) emissions. Results of the sensitivity studies using both models are discussed. Large ozone reductions are found to be outside the expected range of validity of these models and are to be anticipated if there should be a large fleet of stratospheric aircraft with NO(x) emission characteristics of current commercial aircraft. Under the test conditions, a global ozone reduction of about 9 percent is estimated for a jet engine emission index of 15 in both models. If engines are redesigned to reduce the emission index to the NASA goal of 5, global average ozone reductions are between 2 and 3 percent, and those of the Northern Hemisphere are about 4 percent. The effects of stratospheric aircraft on ozone could be further reduced through operation at lower altitudes, reduction of aircraft, and efficient fuel consumption.

  6. 5-year analysis of background surface ozone and carbon dioxide variations during summer seasons at Terra Nova Bay (Antarctica)

    NASA Astrophysics Data System (ADS)

    Cristofanelli, Paolo; Bonasoni, Paolo; Bonafe', Ubaldo; Calzolari, Frencescopiero; Duchi, Rocco; Lanconelli, Christian; Lupi, Angelo; Vitale, Vito; Colombo, Tiziano

    2010-05-01

    Carbon dioxide (CO2) and tropospheric ozone (O3) play important roles in determining the radiative budget of the atmosphere. While CO2 is considered the most important anthropogenic greenhouse gas, O3 is evaluated as the third most powerful greenhouse gas since pre-industrial ages and, by influencing the lifetime of others greenhouse gases, it provides also an indirect impact on climate. Within the framework of the Italian National Programme of Antarctic Researches (PNRA), continuous measurements of CO2, O3 as well as meteorological parameters have been conducted at the clean-air facility of Icaro Camp at the "Mario Zucchelli" Station (74.7 S, 164.1 E, 41 m a.s.l., hereinafter MZS-IC) during five experimental summer campaigns from November 2001 to February 2006. At MZS-IC, average O3 background concentrations ranged from 18.5 +/- 4.6 ppbv (summer 2005 - 2006) to 22.0 +/- 4.3 ppbv (summer 2003 - 2004). For CO2, in good agreement with the global trend observed for the period 2001-2006, background concentrations showed an average growth rate of 2.12 ppmv/year ranging from 369.28 +/- 0.18 ppmv during the summer 2001 - 2002 to 377.76 +/- 0.26 ppmv during the summer 2005 - 2006. On average, over the five summer campaigns, the O3 behaviour showed a decreasing trend with highest values in November and a minimum in January, while a broad December-January minimum characterised CO2, well tracing the typical O3 and CO2 high-latitude seasonal cycles in the Southern Hemisphere.

  7. Comparisons of the film peeling from the composite oxides of quartz sand filters using ozone, hydrogen peroxide and chlorine dioxide.

    PubMed

    Guo, Yingming; Huang, Tinglin; Wen, Gang; Cao, Xin

    2015-08-01

    To solve the problem of shortened backwashing intervals in groundwater plants, several disinfectants including ozone (O3), hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) were examined to peel off the film from the quartz sand surface in four pilot-scale columns. An optimized oxidant dosage and oxidation time were determined by batch tests. Subsequently, the optimized conditions were tested in the four pilot-scale columns. The results demonstrated that the backwashing intervals increased from 35.17 to 54.33 (H2O2) and to 53.67 hr (ClO2) after the oxidation treatments, and the increase of backwashing interval after treatment by O3 was much less than for the other two treatments. Interestingly, the treatment efficiency of filters was not affected by O3 or H2O2 oxidation; but after oxidation by ClO2, the treatment efficiency was deteriorated, especially the ammonia removal (from 96.96% to 24.95%). The filter sands before and after the oxidation were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. Compared with the oxidation by O3 and H2O2, the structures on the surface of filter sands were seriously damaged after oxidation by ClO2. The chemical states of manganese on the surfaces of those treated sands were only changed by ClO2. The damage of the structures and the change of the chemical states of manganese might have a negative effect on the ammonia removal. In summary, H2O2 is a suitable agent for film peeling.

  8. Contribution of ozone to airborne aldehyde formation in Paris homes.

    PubMed

    Rancière, Fanny; Dassonville, Claire; Roda, Célina; Laurent, Anne-Marie; Le Moullec, Yvon; Momas, Isabelle

    2011-09-15

    Indoor aldehydes may result from ozone-initiated chemistry, mainly documented by experimental studies. As part of an environmental investigation included in the PARIS birth cohort, the aim of this study was to examine ozone contribution to airborne aldehyde formation in Paris homes. Formaldehyde, acetaldehyde and hexaldehyde levels, as well as styrene, nitrogen dioxide and nicotine concentrations, comfort parameters and carbon dioxide levels, were measured twice during the first year of life of the babies. Ambient ozone concentrations were collected from the closest background station of the regional air monitoring network. Traffic-related nitrogen oxide concentrations in front of the dwellings were estimated by an air pollution dispersion model. Home characteristics and families' way of life were described by questionnaires. Stepwise multiple linear regression models were used to link aldehyde levels with ambient ozone concentrations and a few aldehyde precursors involved in oxidation reactions, adjusting for other indoor aldehyde sources, comfort parameters and traffic-related nitrogen oxides. A 4 and 11% increase in formaldehyde and hexaldehyde levels was pointed out when 8-hour ozone concentrations increased by 20 μg/m(3). The influence of potential precursors such as indoor styrene level and frequent use of air fresheners, containing unsaturated volatile organic compounds as terpenes, was also found. Thus, our results suggest that ambient ozone can significantly impact indoor air quality, especially with regard to formaldehyde and hexaldehyde levels.

  9. Impacts of Human Alteration of the Nitrogen Cycle in the U.S. on Radiative Forcing

    EPA Science Inventory

    Nitrogen cycling processes affect radiative forcing directly through emissions of nitrous oxide (N2O) and indirectly because emissions of nitrogen oxide (NO x ) and ammonia (NH3) affect atmospheric concentrations of methane (CH4), carbon dioxide (CO2), water vapor (H2O), ozone (O...

  10. Transport and deposition of nitrogen oxides and ozone in the atmospheric surface layer

    NASA Astrophysics Data System (ADS)

    Li, Yongxian

    Tropospheric ozone is an important photochemical air pollutant, which increases respiratory-related diseases, decreases crop yields, and causes other environmental problems. This research has focused on the measurement of soil biogenic emissions of nitric oxide (NO), one of the precursors for ozone formation, from intensively managed soils in the Southeast US, and examined the transport and deposition of NOx (NO + NO2) and ozone in the atmospheric surface layer, and the effects of NO emissions and its chemical reactions on ozone flux and deposition to the earth's surface. Emissions of nitric oxide were measured from an intensively managed agricultural soil, in the lower coastal plain of North Carolina (near Plymouth, NC), using a dynamic chamber technique. Measurements of soil NO emissions in several crop canopies were conducted at four different sites in North Carolina during late spring and summer of 1994-1996. The turbulent fluxes of NO2 and O3 at 5 m and 10 m above the ground were measured using the eddy-correlation technique near Plymouth, NC during late spring of 1995 and summer of 1996, concurrent with measurements of soil NO emissions using the dynamic chamber system. Soil NO emission from within the corn field was high averaging approximately 35 ng N/m2/s during the measurement period of 1995. In another study, vertical measurements of ozone were made on a 610 m tall tower located 15 km Southeast of Raleigh, NC during the summers of 1993-1997, as part of an effort by the State of North Carolina to develop a State Implementation Plan (SIP) for ozone control in the Raleigh Metropolitan Statistical Area. A strong correlation was observed between the nighttime and early morning ozone concentrations in the residual layer (CR) above the NBL and the maximum ground level concentration (C o max) the following afternoon. Based on this correlation, an empirical regression equation (Co max = 27.67*exp(0.016 CR)) was developed for predicting maximum ground level ozone

  11. Which metric of ambient ozone to predict daily mortality?

    NASA Astrophysics Data System (ADS)

    Moshammer, Hanns; Hutter, Hans-Peter; Kundi, Michael

    2013-02-01

    It is well known that ozone concentration is associated with daily cause specific mortality. But which ozone metric is the best predictor of the daily variability in mortality? We performed a time series analysis on daily deaths (all causes, respiratory and cardiovascular causes as well as death in elderly 65+) in Vienna for the years 1991-2009. We controlled for seasonal and long term trend, day of the week, temperature and humidity using the same basic model for all pollutant metrics. We found model fit was best for same day variability of ozone concentration (calculated as the difference between daily hourly maximum and minimum) and hourly maximum. Of these the variability displayed a more linear dose-response function. Maximum 8 h moving average and daily mean value performed not so well. Nitrogen dioxide (daily mean) in comparison performed better when previous day values were assessed. Same day ozone and previous day nitrogen dioxide effect estimates did not confound each other. Variability in daily ozone levels or peak ozone levels seem to be a better proxy of a complex reactive secondary pollutant mixture than daily average ozone levels in the Middle European setting. If this finding is confirmed this would have implications for the setting of legally binding limit values.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

    Hood, D.B.

    1991-01-01

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

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

    SciTech Connect

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

    1982-11-01

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

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

    SciTech Connect

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

    1989-02-01

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

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

    PubMed

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

    1991-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

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

    SciTech Connect

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

    1986-10-01

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

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

    PubMed

    Woodill, Laurie A; Hinrichs, Ryan Z

    2010-09-28

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

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Nirel, Ronit; Dayan, Uri

    2001-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    SciTech Connect

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

    1987-01-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2010-01-01

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

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

    PubMed Central

    2009-01-01

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

  9. Effects of oxides of nitrogen on California air quality. Final report

    SciTech Connect

    Not Available

    1986-03-01

    The report was written because of California Air Resources Board concerns about the multiple effects of oxides of nitrogen (NOx) emissions on California air quality. The deleterious effects are expected to increase because NOx emissions are expected to increase in 1990's. The report discusses six major products of nitrogen oxide (NOx) emissions: nitrogen dioxide, ozone, particulate nitrates, acid deposition, visibility impairment, other nitrogen compounds. For each product, the report describes health and welfare effects, atmospheric chemistry by which NOx emissions are transformed into various air pollutants, relevant ambient air quality standards, ambient concentrations measured in California, and status in attaining ambient air standards. Because ozone is California's most severe air pollution problem, the report discusses in depth the relationship of NOx and ozone. In most areas of California, ozone strategies have reduced hydrocarbon emissions while maintaining NOx emissions. Evidence is increasing that reduction of NOx emissions also reduces ozone.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  11. Reactive Nitrogen, Ozone and Ozone Production in the Arctic Troposphere and the Impact of Stratosphere-Troposphere Exchange

    NASA Technical Reports Server (NTRS)

    Liang, Q.; Rodriquez, J. M.; Douglass, A. R.; Crawford, J. H.; Apel, E.; Bian, H.; Blake, D. R.; Brune, W.; Chin, M.; Colarco, P. R.; daSilva, A.; Diskin, G. S.; Duncan, B. N.; Huey, L. C.; Knapp, D. J.; Montzka, D. D.; Nielsen, J. E.; Olson, J. R.; Pawson, S.; Weinheimer, A. J.

    2011-01-01

    We analyze the aircraft observations obtained during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellite (ARCTAS) mission together with the GEOS-5 CO simulation to examine O3 and NOy in the Arctic and sub-Arctic region and their source attribution. Using a number of marker tracers and their probability density distributions, we distinguish various air masses from the background troposphere and examine their contribution to NOx, O3, and O3 production in the Arctic troposphere. The background Arctic troposphere has mean O3 of approximately 60 ppbv and NOx of approximately 25 pptv throughout spring and summer with CO decreases from approximately 145 ppbv in spring to approximately 100 ppbv in summer. These observed CO, NOx and O3 mixing ratios are not notably different from the values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns despite the significant changes in the past two decades in processes that could have changed the Arctic tropospheric composition. Air masses associated with stratosphere-troposphere exchange are present throughout the mid and upper troposphere during spring and summer. These air masses with mean O3 concentration of 140-160 ppbv are the most important direct sources of O3 in the Arctic troposphere. In addition, air of stratospheric origin is the only notable driver of net O3 formation in the Arctic due to its sustainable high NOx (75 pptv in spring and 110 pptv in summer) and NOy (approximately 800 pptv in spring and approximately 1100 pptv in summer) levels. The ARCTAS measurements present observational evidence suggesting significant conversion of nitrogen from HNO3 to NOx and then to PAN (a net formation of approximately 120 pptv PAN) in summer when air of stratospheric origin is mixed with tropospheric background during stratosphere-to-troposphere transport. These findings imply that an adequate representation of stratospheric O3 and NOy input are essential in accurately simulating O3

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

    NASA Technical Reports Server (NTRS)

    Kuramoto, N.; Takiguchi, H.

    1984-01-01

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

  13. Short-Time-Response measurements of nitrogen dioxide and peroxyacetyl nitrate by fast capillary gas chromatography with luminol detection.

    SciTech Connect

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

    2000-12-07

    The interaction of hydrocarbons and nitrogen oxides in sunlight to produce photochemical smog has been well studied over the years. In the past, the workhorse for the measurement of NO{sub 2}and NO was the chemiluminescent reaction with ozone. This method has detection limits of approximately 0.5 ppb in most commercial instruments, but it cannot detect NO{sub 2} directly; the instrument detects NO and uses hot catalytic surfaces to decompose all other nitrogen oxides (including NO{sub 2}) to NO for detection (l). The main problem with the method is the inherent difficulty in detecting excited NO{sub 2}, which emits over a broad region beginning at approximately 660 nm and has a maximum at 1270 nm, thus requiring a red-shifted photomultiplier for detection. The use of luminol for direct chemiluminescent detection of NO{sub 2} was demonstrated to have greater inherent sensitivity (detection limits of 5 ppt) than the indirect ozone chemiluminescence detection (2). In the luminol system, a gas-liquid reaction leads to light emission with a maximum at approximately 425 nm, at the maximum sensitivity for most photomultiplier tubes. This emission is responsible for the increased detection sensitivities. The biggest problem with this method for direct measurement of NO{sub 2} has been interference due to other soluble oxidants, particularly peroxyacyl nitrates (PANs).

  14. Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

    SciTech Connect

    Lu, Z.; Streets, D. G.; de Foy, B.; Lamsal, L. N.; Duncan, B. N.; Xing, J.

    2015-05-28

    Satellite remote sensing of tropospheric nitrogen dioxide (NO2) can provide valuable information for estimating surface nitrogen oxides (NOx) emissions. Using an exponentially-modified Gaussian (EMG) method and taking into account the effect of wind on observed NO2 distributions, we estimate three-year moving-average emissions of summertime NOx from 35 US urban areas directly from NO2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005–2014. Following the conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NOx emissions from each urban area by applying the EMG method to OMI data with wind speeds greater than 3–5 m s-1. Meanwhile, we find that OMI NO2 observations under weak-wind conditions (i.e., < 3 m s-1) are qualitatively better correlated with the surface NOx source strength in comparison to all-wind OMI maps; and therefore we use them to calculate the satellite-observed NO2 burdens of urban areas and compare with NOx emission estimates. The EMG results show that OMI-derived NOx emissions are highly correlated (R > 0.93) with weak-wind OMI NO2 burdens as well as bottom-up NOx emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous, EMG-obtained, effective NO2 lifetimes (~3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO2 chemical lifetimes. In general, isolated urban areas with NOx emission intensities greater than ~ 2 Mg h-1 produce statistically significant weak-wind signals in three-year average OMI data. From 2005 to 2014, we estimate that total OMI

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

    PubMed

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

    2016-07-01

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

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

    PubMed

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

    2014-04-01

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

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

    PubMed

    Morales, J A; Walsh, J E

    2005-07-01

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

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

    PubMed

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

    2008-08-01

    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 [O3], alone and in combination, affect tree water use of pure aspen and mixed aspen-birch forests in the free air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). Measurements of sap flux and canopy leaf area index (L) were made during two growing seasons, when steady-state L had been reached after more than 6 years of exposure to elevated [CO2] and [O3]. Maximum stand-level sap flux was not significantly affected by elevated [O3], but was increased by 18% by elevated [CO2] averaged across years, communities and O(3) regimes. Treatment effects were similar in pure aspen and mixed aspen-birch communities. Increased tree water use in response to elevated [CO2] was related to positive CO2 treatment effects on tree size and L (+40%). Tree water use was not reduced by elevated [O3] despite strong negative O3 treatment effects on tree size and L (-22%). Elevated [O3] predisposed pure aspen stands to drought-induced sap flux reductions, whereas increased tree water use in response to elevated [CO2] did not result in lower soil water content in the upper soil or decreasing sap flux relative to control values during dry periods. Maintenance of soil water content in the upper soil in the elevated [CO2] treatment was at least partly a function of enhanced soil water-holding capacity, probably a result of increased organic matter content from increased litter inputs. Our findings that larger trees growing in elevated [CO2] used more water and that tree size, but not maximal water use, was negatively affected by elevated [O3] suggest that the long-term cumulative effects on stand structure may be more important than the expected primary stomatal closure responses to

  19. Mass transfer phenomena of gaseous hydrocarbons and nitrogen dioxide across gas-inorganic pigments boundaries

    NASA Astrophysics Data System (ADS)

    Birbatakou, S.; Pagopoulou, I.; Kalantzopoulos, A.; Roubani-Kalantzopoulou, F.

    1998-11-01

    Reversed-flow gas chromatography was used to study the kinetics of the action of five hydrocarbons namely, ethane, ethene, ethyne, propene and butene and of the nitrogen dioxide, on three known and widely used pigments, the white one TiO2, and the yellows CdS and PbCrO4. The calculation of kinetic parameters and mass transfer coefficients is based on an experimental adsorption isotherm. All these calculations are based on a non linear adsorption isotherm model as it is well accepted that the linear one is inadequate for inorganic substances like these mentioned in this work. The inadequacy is mainly attributed to the non-uniformity of the solid surface. Five physicochemical parameters have been obtained for each of the twenty heterogeneous reactions studied. With these systematic experiments under conditions which are similar to the atmospheric ones, an extrapolation of the results obtained to “real" atmospheres with a high degree of confidence is possible. Some of the calculations were based on the linear model for comparison. La cinétique de la réaction de cinq hydrocarbures (éthane, éthylène, acétylène, propène, boutène) et du dioxyde d'azote avec trois pigments (le blanc de TiO2 et les jaunes de CdS et PbCrO4) a été étudiée par chromatographie en phase gazeuse a flux inversé. Le calcul des paramètres cinétiques et des coefficients de transfert de masse a été effectué à partir des isothermes d'adsorption expérimentales en faisant l'hypothèse d`un modèle d'adsorption non-linéaire, qui résulte de la non-uniformité de la surface. Cinq paramètres physico-chimiques ont été obténus pour chacune des vingt réaction hétérogènes étudiées. À partir de ces résultats obténus dans des conditions similaires aux conditions atmosphériques, l'extrapolation à des atmosphères réelles paraît possible avec une bonne confiance. Quelques calculs ont été effectués avec un modèle linéaire pour comparaison.

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

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

  1. Indoor-outdoor relationships of airborne particles and nitrogen dioxide inside Parisian buses

    NASA Astrophysics Data System (ADS)

    Molle, Romain; Mazoué, Sophie; Géhin, Évelyne; Ionescu, Anda

    2013-04-01

    This study evaluated passengers' exposure to traffic air pollution inside the articulated buses of the line 91 in Paris during 10 working days in May, 2010. Twenty articulated buses were studied on 32 routes in order to determine the influence of the sampling position on the pollutant concentrations. This parameter is still poorly known for the rigid buses and is even less known for the articulated ones. However this parameter must be studied for articulated buses because the greater length may cause a pollutant concentration gradient in the cabin. Portable devices were used to measure pollutants in the presence of passengers from 8 a.m. to 9 a.m. and from 4 p.m. to 5 p.m., time periods corresponding to the peak traffic and travellers. PM2.5 mass concentration, particle number concentration between 0.3 and 20 μm and nitrogen dioxide concentration were simultaneously measured on three positions inside the buses (front, middle and rear) in order to study the spatial distribution of these compounds. These measurements inside the buses were compared to the outdoor concentrations at the same moment of the day provided by the Parisian air quality monitoring network; they were also compared to the results of a previous monitoring campaign performed in 2008. The results obtained during the 2010 campaign revealed that in-cabin NO2 mean concentrations were 1.5-3.5 times higher than the outside concentration levels; a maximum concentration of 234 ± 40 μg m-3 was found in the rear position (location of the engine and exhaust gas). Mean in-cabin PM2.5 mass concentrations varied from one week to another one, but they were globally the same at the three positions inside the instrumented buses. In order to determine the impact of outdoor levels, correlations have been calculated between the results measured inside the buses and those measured by the outdoor air monitoring stations. The highest Pearson correlation coefficient was 0.29 for NO2 data whereas the highest Pearson

  2. Broadband cavity enhanced spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Attwood, A. R.; Flores, J. M.; Rudich, Y.; Brown, S. S.

    2015-09-01

    Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity enhanced spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99933 ± 0.00003 (670 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.49 km within the 1 m cell. We measure the cavity output over the 315-350 nm spectral region using a grating monochromator and charge-coupled device (CCD) array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity enhanced spectroscopy and cavity ringdown spectroscopy agree within 2 % (slope for linear fit = 0.98 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity enhanced spectroscopy and calculated based on flow dilution are also well-correlated, with r2 = 0.9998. During constant, mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1-min detection limit for extinction measurements at 315-350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically-based trace gas detection that may complement higher precision techniques based on non-absolute detection methods. In addition to trace gases, this approach will be appropriate for

  3. Partial oxidation of methane to methanol with nitrogen dioxide in dielectric barrier discharge plasma: experimental and molecular modeling

    NASA Astrophysics Data System (ADS)

    Indarto, Antonius

    2016-04-01

    Non-catalytic conversion of methane (CH4) and nitrogen dioxide (NO2) into methanol (CH3OH) has been conducted and presented in this paper. Experiments were carried out using dielectric barrier discharge as the reaction medium in atmospheric pressure and temperature conditions. High yield production of methanol was achieved (18-20% mol) by single-stage plasma reaction with maximum selectivity of 32% mol. Compared to other oxidants, such as O2, the presence of NO2 in the plasma reaction resulted in higher methanol selectivity. For better understanding of the reactions, density functional theory calculations were also performed and discussed.

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

    SciTech Connect

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

    1984-01-01

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

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

    SciTech Connect

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

    1990-08-01

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

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

    SciTech Connect

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

    1990-08-01

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

  7. Short-term exposure to 0. 3 ppm nitrogen dioxide does not potentiate airway responsiveness to sulfur dioxide in asthmatic subjects

    SciTech Connect

    Rubinstein, I.; Bigby, B.G.; Reiss, T.F.; Boushey, H.A. Jr. )

    1990-02-01

    Whether short-term exposure to low levels of nitrogen dioxide (NO2) enhances airway responsiveness in asthmatic subjects is controversial. Because it is well established that asthma is associated with increased airway responsiveness to another common air pollutant, sulfur dioxide (SO2), we examined whether short-term exposure of asthmatic subjects to 0.3 ppm NO2 potentiates airway responsiveness to inhaled SO2. We exposed nine subjects with clinically stable asthma to 0.3 ppm NO2 or filtered air in an environmental room for 30 min on 2 separate days at least 1 wk apart in a double-blind, randomized fashion. A questionnaire about common symptoms related to inhaled irritants was completed before and immediately after each exposure. Each subject exercised (60 to 80 W) on a cycloergometer during the first 20 min of each exposure. We measured specific airway resistance (SRaw) and FEV1/FVC before, 5 min after, and 1 h after completion of the air or NO2 exposure. The single-breath nitrogen test (SBN2) was also performed before and 1 h after completion of the air or NO2 exposures and closing volume was determined; subsequently, SO2 dose-response curves (0.25 to 4.0 ppm) were performed via a mouthpiece. Each dose of SO2 was inhaled at a minute ventilation of 20 L/min for 4 min and was doubled until SRaw increased by at least 8 U above baseline. The dose of SO2 required to provoke an increase in SRaw of 8 U above baseline was determined by linear interpolation from the dose-response curve (PD8Uso2).

  8. Insights into the Electronic Structure of Ozone and Sulfur Dioxide from Generalized Valence Bond Theory: Bonding in O3 and SO2.

    PubMed

    Takeshita, Tyler Y; Lindquist, Beth A; Dunning, Thom H

    2015-07-16

    There are many well-known differences in the physical and chemical properties of ozone (O3) and sulfur dioxide (SO2). O3 has longer and weaker bonds than O2, whereas SO2 has shorter and stronger bonds than SO. The O-O2 bond is dramatically weaker than the O-SO bond, and the singlet-triplet gap in SO2 is more than double that in O3. In addition, O3 is a very reactive species, while SO2 is far less so. These disparities have been attributed to variations in the amount of diradical character in the two molecules. In this work, we use generalized valence bond (GVB) theory to characterize the electronic structure of ozone and sulfur dioxide, showing O3 does indeed possess significant diradical character, whereas SO2 is effectively a closed shell molecule. The GVB results provide critical insights into the genesis of the observed difference in these two isoelectronic species. SO2 possesses a recoupled pair bond dyad in the a"(π) system, resulting in SO double bonds. The π system of O3, on the other hand, has a lone pair on the central oxygen atom plus a pair of electrons in orbitals on the terminal oxygen atoms that give rise to a relatively weak π interaction.

  9. Characterization of the Spatial Variability of Methane, Ozone, and Carbon Dioxide in Two Oil and Gas Production Basins Via a Spatial Grid of Continuous Measurements

    NASA Astrophysics Data System (ADS)

    Casey, J. G.; Collier, A. M.; Hannigan, M.; Piedrahita, R.; Vaughn, B. H.; Sherwood, O.

    2015-12-01

    In recent years, aided by the advent of horizontal drilling used in conjunction with hydraulic fracturing, oil and gas production in basins around the United States has increased significantly. A study was conducted in two oil and gas basins during the spring and summer of 2015 to investigate the spatial and temporal variability of several atmospheric trace gases that can be influenced by oil and gas extraction including methane, ozone, and carbon dioxide. Fifteen air quality monitors were distributed across the Denver Julesburg Basin in Northeast Colorado, and the San Juan Basin, which stretches from Southwest Colorado into Northwest New Mexico in Four Corners Region. Spatial variability in ozone was observed across each basin. The presence of dynamic short-term trends observed in the mole fraction of methane and carbon dioxide indicate the extent to which each site is uniquely impacted by local emission sources. Diurnal trends of these two constituents lead toward a better understanding of local pooling of emissions that can be influenced by topography, the planetary boundary layer height, atmospheric stability, as well as the composition and flux of local and regional emissions sources.

  10. Effect of canopy structure and open-top chamber techniques on micrometeorological parameters and the gradients and transport of water vapor, carbon dioxide and ozone in the canopies of plum trees (`prunus salicina`) in the San Joaquin valley. Final report

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L.; Metheny, P.A.; Malkus, P.; Wosnik, K.

    1995-03-15

    Plum trees (Prunus salicina cv. Casselman) were exposed to ozone in open-top chambers (OTC) or chamberless plots, and trace gas concentrations and microenvironmental conditions were monitored within tree canopies inside the outside the OTC. Concentrations of ozone, carbon dioxide and water vapor, leaf and air temperature, light intensity, and wind speed were measured at nine positions in the tree canopies. The objectives were to: (1) map the distribution of microenvironmental parameters within the canopies inside and outside the OTC; (2) determine transport parameters for gas exchange, and (3) calculate ozone flux. Significant vertical and horizontal gradients were observed; gradients were diminished and often inverted inside relative to outside the OTC due to air distribution at the bottom of the OCT. Ozone flux was readily modeled from measures of stomatal conductance, nonstomatal conductance and ozone concentration at the leaf surface.

  11. Responses of two summer annuals to interactions of atmospheric carbon dioxide and soil nitrogen

    SciTech Connect

    Thomas, R.B.

    1987-01-01

    The competitive relationship between Chenopodium album L. (C{sub 3}) and Amaranthus hybridus L. (C{sub 4}) was investigated in two atmospheric CO{sub 2} levels and tow soil nitrogen levels. Biomass and leaf surface area of Amaranthus plants did not respond to CO{sub 2} enrichment. Only in high nitrogen did Chenopodium plants respond to increased CO{sub 2} with greater biomass and leaf surface area. Nitrogen use efficiency (NUE) was higher in Amaranthus than in Chenopodium in all treatments except for the high-nitrogen high-CO{sub 2} treatment. Under conditions of high nitrogen and low CO{sub 2}, Chenopodium was a poor competitor, but competition favored Chenopodium in high nitrogen and high CO{sub 2}. In low nitrogen and high CO{sub 2}, competition favored Chenopodium on a dry weight basis, but favored Amaranthus on a seed weight basis, reflecting early senescence of Chenopodium. In low nitrogen and high CO{sub 2}, competition favored Amaranthus on a dry weight basis, but favored Chenopodium on a seed weight basis. Physiological aspects of the growth of Chenopodium and Amaranthus were studied. Acclimation to elevated CO{sub 2} occurred at the enzyme level in Chenopodium. Under conditions of high nitrogen and no competition, individual Chenopodium plants responded to elevated CO{sub 2} with greater biomass, leaf surface area, and maximum net photosynthetic rates. In high nitrogen, leaf nitrogen, soluble protein, and RuBP carboxylase activity of Chenopodium decreased and NUE increased when grown in elevated CO{sub 2}. In low nitrogen without competition, Chenopodium showed no significant response to CO{sub 2} enrichment. Amarantus grown in high and low nitrogen without competition showed no significant changes in leaf nitrogen, soluble protein, carboxylase activity, chlorophyll, or NUE of in response to CO{sub 2} enrichment.

  12. Effects of nitrogen dioxide on growth and yield of black turtle bean (Phaseolus vulgaris L.) cv. 'Domino'.

    PubMed

    Sandhu, R; Gupta, G

    1989-01-01

    Twenty-six-day-old black turtle bean cv. 'Domino' plants were exposed to nitrogen dioxide (0.0, 0.025, 0.05 and 0.10 microl liter(-1)), 7 h per day for 5 days per week for 3 weeks, under controlled environment. Data were collected on net photosynthesis rate (PN), stomatal resistance (SR), and dark respiration rate (DR), immediately after exposure, 24 h after the termination of exposure and at maturity (when the leaves had just started turning yellow), using a LICOR 6000 Portable Photosynthesis System. Chlorophyll-a (Ch-a), chlorophyll-b (Ch-b), total chlorophyll (tot-Ch) and leaf nitrogen were measured immediately after exposure and at maturity. Growth characteristics-relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and root: shoot ratio (RSR)-were computed for treated plants. Net photosynthesis rate increased by 53% in 0.10 microl liter(-1) NO2 treated plants immediately after exposure compared to control plants. Dark respiration rates were also higher in treated plants. Ch-a, Ch-b and tot-Ch showed significant increases with 0.1 microl liter(-1) NO2 treatment immediately after exposure. Foliar nitrogen content showed an increase in treated plants both immediately after exposure and at maturity. Increases were also seen in RGR and NAR. Plant yield increased by 86% (number of pods), 29% (number of seeds) and 46% (weight of seeds), respectively. Nitrogen dioxide stimulated the overall plant growth and crop yield. PMID:15092401

  13. Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution.

    PubMed

    Hewitt, C N; MacKenzie, A R; Di Carlo, P; Di Marco, C F; Dorsey, J R; Evans, M; Fowler, D; Gallagher, M W; Hopkins, J R; Jones, C E; Langford, B; Lee, J D; Lewis, A C; Lim, S F; McQuaid, J; Misztal, P; Moller, S J; Monks, P S; Nemitz, E; Oram, D E; Owen, S M; Phillips, G J; Pugh, T A M; Pyle, J A; Reeves, C E; Ryder, J; Siong, J; Skiba, U; Stewart, D J

    2009-11-01

    More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an "environmentally friendly" fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O(3)), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O(3) concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O(3) concentrations will reach 100 parts per billion (10(9)) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.

  14. Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution

    PubMed Central

    Hewitt, C. N.; MacKenzie, A. R.; Di Carlo, P.; Di Marco, C. F.; Dorsey, J. R.; Evans, M.; Fowler, D.; Gallagher, M. W.; Hopkins, J. R.; Jones, C. E.; Langford, B.; Lee, J. D.; Lewis, A. C.; Lim, S. F.; McQuaid, J.; Misztal, P.; Moller, S. J.; Monks, P. S.; Nemitz, E.; Oram, D. E.; Owen, S. M.; Phillips, G. J.; Pugh, T. A. M.; Pyle, J. A.; Reeves, C. E.; Ryder, J.; Siong, J.; Skiba, U.; Stewart, D. J.

    2009-01-01

    More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an “environmentally friendly” fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O3), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O3 concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O3 concentrations will reach 100 parts per billion (109) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided. PMID:19841269

  15. Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution

    NASA Astrophysics Data System (ADS)

    Hewitt, Nick; Lee, James

    2010-05-01

    More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an ‘‘environmentally friendly'' fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O3), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O3 concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O3 concentrations will reach 100 parts per billion (109) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.

  16. Origin and Variability of Upper Tropospheric Nitrogen Oxides and Ozone at Northern Mid-Latitudes

    NASA Technical Reports Server (NTRS)

    Grewe, V.; Brunner, D.; Dameris, M.; Grenfell, J. L.; Hein, R.; Shindell, D.; Staehelin, J.

    1999-01-01

    Measurements of NO(x) and ozone performed during the NOXAR project are compared with results from the coupled chemistry-climate models ECHAM4.L39(DLR)/CHEM and GISS-model. The measurements are based on flights between Europe and the East coast of America and between Europe and the Far East in the latitude range 40 deg N to 65 deg N. The comparison concentrates on tropopause altitudes and reveals strong longitudinal variations of seasonal mean NO,, of 200 pptv. Either model reproduced strong variations 3 km below but not at the tropopause, indicating a strong missing NO(x) or NO(y) sink over remote areas, e.g. NO(x) to HNO3 conversion by OH from additional OH sources or HNO3 wash-out. Vertical profiles show maximum NO(x) values 2-3 km below the tropopause with a strong seasonal cycle. ECHAM4.L39(DLR)/CHEM reproduces a maximum, although located at the tropopause with a less pronounced seasonal cycle, whereas the GISS model reproduces the seasonal cycle but not the profile's shape due to its coarser vertical resolution. A comparison of NO(x) frequency distributions reveals that both models are capable of reproducing the observed variability, except that ECHAM4.L39(DLR)/CHEM shows no very high NO(x) mixing ratios. Ozone mean values, vertical profiles and frequency distributions are much better reproduced in either model, indicating that the NO(x) frequency distribution, namely the most frequent NO(x) mixing ratio, is more important for the tropospheric photochemical ozone production than its mean value. Both models show that among all sources, NO(x) from lightning contributes most to the seasonal cycle of NO(x) at tropopause altitudes. The impact of lightning in the upper troposphere on NO(x) does not vary strongly with altitude, whereas the impact of surface emissions decreases with altitude. However, the models show significant differences in lightning induced NO(x) concentrations, especially in winter, which may be related to the different treatment of the lower

  17. Effects of nitrogen oxide emission controls on Eastern US surface ozone: A comparison between urban cores and rural background sites

    NASA Astrophysics Data System (ADS)

    Rieder, Harald E.; Fiore, Arlene M.

    2016-04-01

    Nitrogen oxide (NOx) emission controls have led to improved air quality over the past two decades, particularly over the Eastern US. In recent work we quantified the effects of the efforts to abate surface ozone (O3) pollution under the NOx State Implementation Plan (NOx SIP Call) for Eastern US background sites (available from the Clean Air Status and Trends Network (CASTNET)) using methods from statistical extreme value theory (Rieder et al., 2013). Our analysis showed that the number of summer (JJA) days above the US national ambient air quality standard (NAAQS) declined on average by a factor of two between 1988-1998 and 1999-2009 and that probabilistic 1-yr O3 return values declined by about 10 ppb between these two time periods. Here we extend the analysis to observations available from the US EPA Air Quality System (AQS), comprising sites ranging from polluted urban cores to rural sites. We focus on changes in (i) the seasonal and annual average number of days with maximum daily 8-hour average surface O3 above the NAAQS and (ii) probabilistic O3 return values following the NOx SIP Call. Particular focus is given on similarities and differences in surface O3 responses on regional to local level and on contrasting urban cores and rural background sites. References: Rieder H.E., Fiore A.M., Polvani L.M., Lamarque J.-F., Fang Y. (2013): Changes in the frequency and return level of high ozone pollution events over the Eastern United States following emission controls, Environ. Res. Lett., 8, 014012, 2013.

  18. Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality.

    PubMed

    Llonch, P; Rodríguez, P; Gispert, M; Dalmau, A; Manteca, X; Velarde, A

    2012-04-01

    The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2; 70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The 'gas mixture' was always considered a fixed effect and the 'live weight' as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N2 and CO2 mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C

  19. Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality.

    PubMed

    Llonch, P; Rodríguez, P; Gispert, M; Dalmau, A; Manteca, X; Velarde, A

    2012-04-01

    The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2; 70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The 'gas mixture' was always considered a fixed effect and the 'live weight' as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N2 and CO2 mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C

  20. Application of a Chemiluminescence Detector for the Measurement of Total Oxides of Nitrogen and Ammonia in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Hodgeson, J. A.; Bell, J. P.; Rehme, K. A.; Krost, K. J.; Stevens, R. K.

    1971-01-01

    By means of the thermal conversion of nitrogen dioxide to the nitric oxide, the chemiluminescent nitric oxide monitor, based on the nitric oxide plus ozone reaction, may be used for monitoring nitrogen dioxide plus nitric oxide (NO(x)). Under conditions previously described, ammonia is also converted to nitric oxide and therefore interferes. A metal surface, gold wool or stainless steel, operated at two different temperatures has been used to convert only nitrogen dioxide or nitrogen dioxide plus ammonia. Quantitative conversion of nitrogen dioxide to nitric oxide has been obtained at temperatures as low as 200 C. Conversion of ammonia is effected at temperatures of 300 C or higher. By the addition of a converter the basic nitric oxide monitor may be used for measuring NO(x) or NO(x) plus ammonia. As an alternate mode, for a fixed high temperature, a specific scrubber is described for removing NH3 without affecting NO2 concentrations.