WorldWideScience

Sample records for atmospheric ozone increases

  1. Unequivocal detection of ozone recovery in the Antarctic Ozone Hole through significant increases in atmospheric layers with minimum ozone

    Science.gov (United States)

    de Laat, Jos; van Weele, Michiel; van der A, Ronald

    2015-04-01

    An important new landmark in present day ozone research is presented through MLS satellite observations of significant ozone increases during the ozone hole season that are attributed unequivocally to declining ozone depleting substances. For many decades the Antarctic ozone hole has been the prime example of both the detrimental effects of human activities on our environment as well as how to construct effective and successful environmental policies. Nowadays atmospheric concentrations of ozone depleting substances are on the decline and first signs of recovery of stratospheric ozone and ozone in the Antarctic ozone hole have been observed. The claimed detection of significant recovery, however, is still subject of debate. In this talk we will discuss first current uncertainties in the assessment of ozone recovery in the Antarctic ozone hole by using multi-variate regression methods, and, secondly present an alternative approach to identify ozone hole recovery unequivocally. Even though multi-variate regression methods help to reduce uncertainties in estimates of ozone recovery, great care has to be taken in their application due to the existence of uncertainties and degrees of freedom in the choice of independent variables. We show that taking all uncertainties into account in the regressions the formal recovery of ozone in the Antarctic ozone hole cannot be established yet, though is likely before the end of the decade (before 2020). Rather than focusing on time and area averages of total ozone columns or ozone profiles, we argue that the time evolution of the probability distribution of vertically resolved ozone in the Antarctic ozone hole contains a better fingerprint for the detection of ozone recovery in the Antarctic ozone hole. The advantages of this method over more tradition methods of trend analyses based on spatio-temporal average ozone are discussed. The 10-year record of MLS satellite measurements of ozone in the Antarctic ozone hole shows a

  2. The increasing threat to stratospheric ozone from dichloromethane

    Science.gov (United States)

    Hossaini, Ryan; Chipperfield, Martyn P.; Montzka, Stephen A.; Leeson, Amber A.; Dhomse, Sandip S.; Pyle, John A.

    2017-06-01

    It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-1980 later this century. However, recent observations show the atmospheric concentration of dichloromethane--an ozone-depleting gas not controlled by the Montreal Protocol--is increasing rapidly. Using atmospheric model simulations, we show that although currently modest, the impact of dichloromethane on ozone has increased markedly in recent years and if these increases continue into the future, the return of Antarctic ozone to pre-1980 levels could be substantially delayed. Sustained growth in dichloromethane would therefore offset some of the gains achieved by the Montreal Protocol, further delaying recovery of Earth's ozone layer.

  3. Ozone Depletion, UVB and Atmospheric Chemistry

    Science.gov (United States)

    Stolarski, Richard S.

    1999-01-01

    The primary constituents of the Earth's atmosphere are molecular nitrogen and molecular oxygen. Ozone is created when ultraviolet light from the sun photodissociates molecular oxygen into two oxygen atoms. The oxygen atoms undergo many collisions but eventually combine with a molecular oxygen to form ozone (O3). The ozone molecules absorb ultraviolet solar radiation, primarily in the wavelength region between 200 and 300 nanometers, resulting in the dissociation of ozone back into atomic oxygen and molecular oxygen. The oxygen atom reattaches to an O2 molecule, reforming ozone which can then absorb another ultraviolet photon. This sequence goes back and forth between atomic oxygen and ozone, each time absorbing a uv photon, until the oxygen atom collides with and ozone molecule to reform two oxygen molecules.

  4. Ozone in the atmosphere. Basic principles, natural and human impacts

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Peter [Technical Univ. Munich (Germany). Immission Research; Dameris, Martin [German Aerospace Center (DLR), Oberpfaffenhofen-Wessling (Germany). Inst. of Atmospheric Physics

    2014-09-01

    Comprehensive coverage of ozone both in the upper and the lower atmosphere. Essential overview of atmospheric ozone research written by two experienced and acknowledged experts. Numerous qualified references to the scientific literature. Peter Fabian and Martin Dameris provide a concise yet comprehensive overview of established scientific knowledge about ozone in the atmosphere. They present both ozone changes and trends in the stratosphere, as well as the effects of overabundance in the troposphere including the phenomenon of photosmog. Aspects such as photochemistry, atmospheric dynamics and global ozone distribution as well as various techniques for ozone measurement are treated. The authors outline the various causes for ozone depletion, the effects of ozone pollution and the relation to climate change. The book provides a handy reference guide for researchers active in atmospheric ozone research and a useful introduction for advanced students specializing in this field. Non-specialists interested in this field will also profit from reading the book. Peter Fabian can look back on a life-long active career in ozone research, having first gained international recognition for his measurements of the global distribution of halogenated hydrocarbons. He also pioneered photosmog investigations in the metropolitan areas of Munich, Berlin, Athens and Santiago de Chile, and his KROFEX facility provided controlled ozone fumigation of adult tree canopies for biologists to investigate the effects of ozone increases on forests. Besides having published a broad range of scientific articles, he has also been the author or editor of numerous books. From 2002 to 2005 he served the European Geosciences Union (EGU) as their first and Founding President. Martin Dameris is a prominent atmospheric modeler whose interests include the impacts of all kinds of natural and man-made disturbances on the atmospheric system. His scientific work focuses on the connections between ozone and

  5. Ozone, Climate, and Global Atmospheric Change

    Science.gov (United States)

    Levine, Joel S.

    1992-01-01

    The delicate balance of the gases that make up our atmosphere allows life to exist on Earth. Ozone depletion and global warming are related to changes in the concentrations of these gases. To solve global atmospheric problems, we need to understand the composition and chemistry of the Earth's atmosphere and the impact of human activities on them.

  6. Improved reference models for middle atmosphere ozone

    Science.gov (United States)

    Keating, G. M.; Pitts, M. C.; Chen, C.

    1990-01-01

    This paper describes the improvements introduced into the original version of ozone reference model of Keating and Young (1985, 1987) which is to be incorporated in the next COSPAR International Reference Atmosphere (CIRA). The ozone reference model will provide information on the global ozone distribution (including the ozone vertical structure as a function of month and latitude from 25 to 90 km) combining data from five recent satellite experiments: the Nimbus 7 LIMS, Nimbus 7 SBUV, AE-2 Stratospheric Aerosol Gas Experiment (SAGE), Solar Mesosphere Explorer (SME) UV Spectrometer, and SME 1.27 Micron Airglow. The improved version of the reference model uses reprocessed AE-2 SAGE data (sunset) and extends the use of SAGE data from 1981 to the 1981-1983 time period. Comparisons are presented between the results of this ozone model and various nonsatellite measurements at different levels in the middle atmosphere.

  7. The Role of the Ozone Hole and Elevated Greenhouse Gases as Drivers of Antarctic Sea Ice Extent Increase Via Changes in Atmospheric Circulation

    Science.gov (United States)

    Pope, J. O.; Orr, A.; Marshall, G.; Abraham, N. L.

    2015-12-01

    Antarctic sea ice extent has displayed an overall increase across the duration of the 35-year satellite record. However, the cause of this increase is uncertain, with both anthropogenic and natural forcing changes proposed as drivers. Here, we investigate two possible anthropogenic forcings that could influence sea ice extent via changes in the near-surface wind field over the Southern Ocean; (i) ozone depletion and (ii) greenhouse gas increases. We employ an atmosphere-only version of the UK Met Office model, HadGEM3, with prescribed sea surface temperatures and sea ice coupled to the UKCA interactive climate-chemistry model. Starting from a pre-industrial control simulation, two additional simulations were spun off, one investigating the forcing from increased 21st century greenhouse gases and one investigating the forcing from the ozone hole. Based on the work of Holland & Kwok (2012) we analyse the changes in Antarctic circulation, in particular the surface wind properties which have been shown to correlate with sea ice extent. We examine changes in the surface wind field in these two model simulations relative to that in the pre-industrial control simulation, compare them to observed changes during the satellite record, and assess their potential role in driving a response in sea ice extent at both continental and regional scales.

  8. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

    2009-01-15

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

  9. A passive sampler for atmospheric ozone

    Energy Technology Data Exchange (ETDEWEB)

    Grosjean, D.; Hisham, M.W.M. (DGA, Inc., Ventura, CA (United States))

    1992-02-01

    A simple, cost-effective passive sampler has been developed for the determination of atmospheric ozone. This passive sampler is based on a colorant which fades upon reaction with ozone, whose concentration can be determined by reflectance measurement of the color change. Direct, on-site measurements are possible, and no chemical analyses are needed. Sampler design and validation studies have been carried out and included quantitative determination of color change vs exposure time (1-8 days), color change vs. ozone concentration (30-350 ppb), and response to changes in sampler configuration that modify the passive sampling rate. With indigo carmine as the colorant, the detection limits are 30 ppb. day and 120 ppb. day using a plastic grid and Teflon filter, respectively, as diffusion barriers. Interferences from nitrogen dioxide, formaldehyde and peroxyacetyl nitrate are 15, 4 and 16%, respectively, thus resulting in a negligible bias when measuring ozone in ambient air.

  10. Proposed ozone reference models for the middle atmosphere

    Science.gov (United States)

    Keating, G. M.; Young, D. F.

    1985-01-01

    Since the publication of the last COSPAR International Reference Atmosphere (CIRA 72), large amounts of ozone data acquired from satellites have become available in addition to increasing quantities of rocketsonde, balloonsonde, Dobson, M83, and Umkehr measurements. From the available archived satellite data, models are developed for the new CIRA using 5 satellite experiments (Nimbus 7 SBUV and LIMS, AEM-2 SAGE, and SME IR and UVS) of the monthly latitudinal and altitudinal variations in the ozone mixing ratio in the middle atmosphere. Standard deviations and interannual variations are also quantified. The satellite models are shown to agree well with a previous reference model based on rocket and balloon measurements.

  11. Atmospheric Ozone and Methane in a Changing Climate

    Directory of Open Access Journals (Sweden)

    Ivar S. A. Isaksen

    2014-07-01

    Full Text Available Ozone and methane are chemically active climate-forcing agents affected by climate–chemistry interactions in the atmosphere. Key chemical reactions and processes affecting ozone and methane are presented. It is shown that climate-chemistry interactions have a significant impact on the two compounds. Ozone, which is a secondary compound in the atmosphere, produced and broken down mainly in the troposphere and stratosphre through chemical reactions involving atomic oxygen (O, NOx compounds (NO, NO2, CO, hydrogen radicals (OH, HO2, volatile organic compounds (VOC and chlorine (Cl, ClO and bromine (Br, BrO. Ozone is broken down through changes in the atmospheric distribution of the afore mentioned compounds. Methane is a primary compound emitted from different sources (wetlands, rice production, livestock, mining, oil and gas production and landfills.Methane is broken down by the hydroxyl radical (OH. OH is significantly affected by methane emissions, defined by the feedback factor, currently estimated to be in the range 1.3 to 1.5, and increasing with increasing methane emission. Ozone and methane changes are affected by NOx emissions. While ozone in general increase with increases in NOx emission, methane is reduced, due to increases in OH. Several processes where current and future changes have implications for climate-chemistry interactions are identified. It is also shown that climatic changes through dynamic processes could have significant impact on the atmospheric chemical distribution of ozone and methane, as we can see through the impact of Quasi Biennial Oscillation (QBO. Modeling studies indicate that increases in ozone could be more pronounced toward the end of this century. Thawing permafrost could lead to important positive feedbacks in the climate system. Large amounts of organic material are stored in the upper layers of the permafrost in the yedoma deposits in Siberia, where 2 to 5% of the deposits could be organic material

  12. Atmospheric Ozone and Methane in a Changing Climate

    OpenAIRE

    Isaksen, Ivar S.A.; Berntsen, Terje K.; Dalsøren, Stig B.; Kostas Eleftheratos; Yvan Orsolini; Bjørg Rognerud; Frode Stordal; Ole Amund Søvde; Christos Zerefos; Holmes, Chris D.

    2014-01-01

    Ozone and methane are chemically active climate-forcing agents affected by climate–chemistry interactions in the atmosphere. Key chemical reactions and processes affecting ozone and methane are presented. It is shown that climate-chemistry interactions have a significant impact on the two compounds. Ozone, which is a secondary compound in the atmosphere, produced and broken down mainly in the troposphere and stratosphre through chemical reactions involving atomic oxygen (O), NOx compounds (NO...

  13. Page 1 § i Measurements of Atmospheric Ozone 297 distribution ...

    Indian Academy of Sciences (India)

    Europe are shown together in Fig. 3. It may be noted that each distribution. | NTTV. |Nº||. 2Lº. •Ü08 -Ji? Q • Gö4 Qg5 & •004 Jö8. Ozone in cm. per km. height. FIG. 3. Height distributions of atmospheric ozone in different latitudes. curve for Kodaikanal has a single pronounced maximum near about 30 km. most of the ozone ...

  14. Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

    Science.gov (United States)

    Cooper, O. R.; Parrish, D. D.; Stohl, A.; Trainer, M.; Nedelec, P.; Thouret, V.; Cammas, J. P.; Oltmans, S. J.; Johnson, B. J.; Tarasick, D.; hide

    2010-01-01

    In the lowermost layer of the atmosphere - the troposphere - ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity1. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA s compliance with its ozone air quality standard.

  15. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine

    Science.gov (United States)

    Prather, Michael J.; Watson, Robert T.

    1990-01-01

    The rise in atmospheric chlorine levels caused by the emission of chlorofluorocarbons and other halocarbons is thought to be the main cause of the appearance of the Antarctic ozone 'hole' in the late 1970s, and the more modest ozone depletion observed over parts of the Northern Hemisphere. Atmospheric bromine, also associated with halocarbon emissions, is believed to contribute to ozone depletion. Over the next decade, further increases in these compounds are inevitable. Model calculations show that by the end of the next century, atmospheric chlorine and bromine levels may return to those prevalent before the onset of the ozone hole, but only if more stringent regulations are applied to halocarbon production than those currently proposed.

  16. Ozone transmittance in a model atmosphere at Ikeja, Lagos state ...

    African Journals Online (AJOL)

    Variation of ozone transmittance with height in the atmosphere for radiation in the 9.6m absorption band was studied using Goody's model atmosphere, with cubic spline interpolation technique to improve the quality of the curve. The data comprising of pressure and temperature at different altitudes (0-22 km) for the month of ...

  17. UV- Radiation Absorption by Ozone in a Model Atmosphere using ...

    African Journals Online (AJOL)

    UV- radiation absorption is studied through variation of ozone transmittance with altitude in the atmosphere for radiation in the 9.6μm absorption band using Goody's model atmosphere with cubic spline interpolation technique to improve the quality of the curve. The data comprising of pressure and temperature at different ...

  18. Leveraging simulated source contributions to improve understanding of atmospheric ozone

    Science.gov (United States)

    Henderson, B. H.; Emery, C.; Zhang, L.; Pinto, J. P.

    2012-12-01

    and model bias will help to dis-aggregate model bias and suggest areas for improvements. Preliminary results indicate that spatial resolution is not the only factor to be considered when attempting to simulate or attribute regional air quality. Rather, difference in models' treatments of atmospheric chemistry and physics must be considered. These preliminary results also confirm earlier findings that agreement between models and measurements is improved as the averaging time of the simulation and measurements are increased. It is also apparent that when analyzing time series over longer time periods (e.g., months), special care should be taken to examine temporal trends in bias as this will improve understanding of the processes in the model. This study evaluates model bias and ozone contributions using time/space categories that account spatial/temporal trends, treating the simulations as representative days rather than traditional time/space paired evaluation. Ultimately, we will attribute model bias to component process and make recommendations for future modeling efforts.

  19. A Review of Atmospheric Ozone and Current Thinking on the Antarctic Ozone Hole.

    Science.gov (United States)

    1987-01-01

    Clark et al.,1977) believe that the most catastrophic cosmic event responsible for ozone depletions could be a supernova occurring within 100 light years...nearby supernovae and climatic and biological consequences Naure265:318-319. Craiq,R.A.,1965,The Upper Atmosphere:Meteorology- and Physic.z.,Academic...329-354. 74 Danielson,E.F. ,1968,Stratospheric-tropospheric exchange N based on radioactivity ,ozone and potential vorticity, J. Atmos. Sci.25:502-518

  20. Attribution of Historical Whole-atmosphere Ozone Forcing to Emissions

    Science.gov (United States)

    Shindell, Drew; Faluvegi, Greg; Nazarenko, Larissa; Bowman, Kevin; Lamarque, Jean--Francois; Voulgarakis, Apostolos; Schmidt, Gavin A.; Pechony, Olga; Ruedy, Reto

    2013-01-01

    Anthropogenic ozone radiative forcing is traditionally separately attributed to tropospheric and stratospheric changes assuming these have distinct causes. Using the interactive composition-climate model GISS-E2-R we find that this assumption is not justified. Our simulations show that changes in emissions of tropospheric ozone precursors have substantial effects on ozone in both regions, as do anthropogenic halocarbon emissions. Based on our results, additional simulations with the NCARCAM3.5 model, and published studies, we estimate industrial era (1850 to 2005) whole-atmosphere ozone forcing of 0.5 W/sq m due to anthropogenic tropospheric precursors and about -0.2 W/sq m due to halocarbons. The net troposphere plus stratosphere forcing is similar to the net halocarbon plus precursor ozone forcing, but the latter provides a more useful perspective. The halocarbon-induced ozone forcing is roughly two-thirds the magnitude of the halocarbon direct forcing but opposite in sign, yielding a net forcing of only 0.1 W/sq m. Thus the net effect of halocarbons has been smaller, while the effect of tropospheric ozone precursors has been greater, than generally recognized.

  1. Ozone vertical distribution in Mars polar atmosphere

    Science.gov (United States)

    Komitov, B.

    On the basis of an ultraviolet spectrum obtained over the north polar region of Mars by Mariner-9, the vertical profile of the ozone density is calculated. A density maximum is found at about 25 km height over the surface of the planet. Its value is about 1×1010molecules cm-3. The obtained result is compared to the results obtained by other authors.

  2. An Ozone Increase in the Antarctic Summer Stratosphere: A Dynamical Response to the Ozone Hole

    Science.gov (United States)

    Stolarski, R. S.; Douglass, A. R.; Gupta, M.; Newman, P. A.; Pawson, S.; Schoeberl, M. R.; Nielsen, J. E.

    2007-01-01

    Profiles of ozone concentration retrieved from the SBUV series of satellites show an increase between 1979 and 1997 in the summertime Antarctic middle stratosphere (approx. 25-10 hPa). Data over the South Pole from ozone sondes confirm the increase. A similar ozone increase is produced in a chemistry climate model that allows feedback between constituent changes and the stratospheric circulation through radiative heating. A simulation that excludes the radiative coupling between predicted ozone and the circulation does not capture this ozone increase. We show that the ozone increase in our model simulations is caused by a dynamical feedback in response to the changes in the stratospheric wind fields forced by the radiative perturbation associated with the Antarctic ozone hole.

  3. Ultraviolet spectrophotometer for measuring columnar atmospheric ozone from aircraft

    Science.gov (United States)

    Hanser, F. A.; Sellers, B.; Briehl, D. C.

    1978-01-01

    An ultraviolet spectrophotometer (UVS) to measure downward solar fluxes from an aircraft or other high altitude platform is described. The UVS uses an ultraviolet diffuser to obtain large angular response with no aiming requirement, a twelve-position filter wheel with narrow (2-nm) and broad (20-nm) bandpass filters, and an ultraviolet photodiode. The columnar atmospheric ozone above the UVS (aircraft) is calculated from the ratios of the measured ultraviolet fluxes. Comparison with some Dobson station measurements gives agreement to 2%. Some UVS measured ozone profiles over the Pacific Ocean for November 1976 are shown to illustrate the instrument's performance.

  4. A Compact Mobile Ozone Lidar for Atmospheric Ozone and Aerosol Profiling

    Science.gov (United States)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-01-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consist of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  5. A compact mobile ozone lidar for atmospheric ozone and aerosol profiling

    Science.gov (United States)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-10-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consists of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  6. Rapid increases in tropospheric ozone production and export from China

    Science.gov (United States)

    Verstraeten, Willem W.; Neu, Jessica L.; Williams, Jason E.; Bowman, Kevin W.; Worden, John R.; Boersma, K. Folkert

    2015-09-01

    Rapid population growth and industrialization have driven substantial increases in Asian ozone precursor emissions over the past decade, with highly uncertain impacts on regional and global tropospheric ozone levels. According to ozonesonde measurements, tropospheric ozone concentrations at two Asian sites have increased by 1 to 3% per year since 2000, an increase thought to contribute to positive trends in the ozone levels observed at North America’s West Coast. However, model estimates of the Asian contribution to North American ozone levels are not well-constrained by observations. Here we interpret Aura satellite measurements of tropospheric concentrations of ozone and its precursor NO2, along with its largest natural source, stratospheric ozone, using the TM5 global chemistry-transport model. We show that tropospheric ozone concentrations over China have increased by about 7% between 2005 and 2010 in response to two factors: a rise in Chinese emissions by about 21% and increased downward transport of stratospheric ozone. Furthermore, we find that transport from China of ozone and its precursors has offset about 43% of the 0.42 DU reduction in free-tropospheric ozone over the western United States that was expected between 2005 and 2010 as a result of emissions reductions associated with federal, state and local air quality policies. We conclude that global efforts may be required to address regional air quality and climate change.

  7. Validation of ozone measurements from the Atmospheric Chemistry Experiment (ACE

    Directory of Open Access Journals (Sweden)

    E. Dupuy

    2009-01-01

    Full Text Available This paper presents extensive {bias determination} analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO instrument. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from nearly 20 satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the average values of the mean relative differences are nearly all within +1 to +8%. At higher altitudes (45–60 km, the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments, with mean relative differences of up to +40% (about +20% on average. For the ACE-MAESTRO version 1.2 ozone data product, mean relative differences are within ±10% (average values within ±6% between 18 and 40 km for both the sunrise and sunset measurements. At higher altitudes (~35–55 km, systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (with mean relative differences down to −10%, the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS, indicating a large positive bias (mean relative differences within +10 to +30% in the 45–55 km altitude range. In contrast, there is no significant systematic difference in bias found for the ACE-FTS sunrise and sunset measurements.

  8. Heterogeneous reactions important in atmospheric ozone depletion: a theoretical perspective.

    Science.gov (United States)

    Bianco, Roberto; Hynes, James T

    2006-02-01

    Theoretical studies of the mechanisms of several heterogeneous reactions involving ClONO(2), H(2)O, HCl, HBr, and H(2)SO(4) important in atmospheric ozone depletion are described, focused primarily on reactions on aqueous aerosol surfaces. Among the insights obtained is the active chemical participation of the surface water molecules in several of these reactions. The general methodology adopted allows reduction of these complex chemical problems to meaningful model systems amenable to quantum chemical calculations.

  9. Comparative study of oxidants and ozone in Los Angeles atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Renzetti, N.A.; Romanovsky, J.C.

    1956-01-01

    The smog in the Pasadena atmosphere was analyzed from July 15 - Nov. 15, 1955. Pasadena is an area of high incidence of smog during this particular time of year. The instruments used were a phenolphthalin oxidant apparatus, a potassium iodide continuous oxidant recorder, a rubber cracking apparatus, and an ozone ultraviolet spectrometer. The instrumentation and measuring methods are described in detail, as well as the laboratory calibrations. The results of the sampling are summarized in graphical form with comments on interferences.

  10. Persistence and photochemical decay of springtime total ozone anomalies in the Canadian Middle Atmosphere Model

    Directory of Open Access Journals (Sweden)

    S. Tegtmeier

    2007-01-01

    Full Text Available The persistence and decay of springtime total ozone anomalies over the entire extratropics (midlatitudes plus polar regions is analysed using results from the Canadian Middle Atmosphere Model (CMAM, a comprehensive chemistry-climate model. As in the observations, interannual anomalies established through winter and spring persist with very high correlation coefficients (above 0.8 through summer until early autumn, while decaying in amplitude as a result of photochemical relaxation in the quiescent summertime stratosphere. The persistence and decay of the ozone anomalies in CMAM agrees extremely well with observations, even in the southern hemisphere when the model is run without heterogeneous chemistry (in which case there is no ozone hole and the seasonal cycle of ozone is quite different from observations. However in a version of CMAM with strong vertical diffusion, the northern hemisphere anomalies decay far too rapidly compared to observations. This shows that ozone anomaly persistence and decay does not depend on how the springtime anomalies are created or on their magnitude, but reflects the transport and photochemical decay in the model. The seasonality of the long-term trends over the entire extratropics is found to be explained by the persistence of the interannual anomalies, as in the observations, demonstrating that summertime ozone trends reflect winter/spring trends rather than any change in summertime ozone chemistry. However this mechanism fails in the northern hemisphere midlatitudes because of the relatively large impact, compared to observations, of the CMAM polar anomalies. As in the southern hemisphere, the influence of polar ozone loss in CMAM increases the midlatitude summertime loss, leading to a relatively weak seasonal dependence of ozone loss in the Northern Hemisphere compared to the observations.

  11. From closing the atmospheric ozone hole to reducing climate change. Lessons learned

    National Research Council Canada - National Science Library

    Ewart, Gary W; Rom, William N; Braman, Sidney S; Pinkerton, Kent E

    2015-01-01

    ... the ozone layer of the earth's atmosphere. The process that led to global agreement on reducing depletion of the ozone layer holds valuable lessons, and some ironies, for scientists and policy makers seeking now to address global climate change...

  12. Impact of near-surface atmospheric composition on ozone formation in Russia

    Science.gov (United States)

    Berezina, Elena; Moiseenko, Konstantin; Skorokhod, Andrey; Belikov, Igor; Pankratova, Natalia; Elansky, Nikolai

    2017-04-01

    One of the consequences of the human impact on the atmosphere is increasing in tropospheric ozone concentration, with the highest ozone level being observed in industrially developed and highly populated regions of the world. In these regions, main anthropogenic sources of carbon monoxide (CO), methane (CH4) and volatile organic compounds (VOCs) are concentrated. The oxidation of these compounds, when interacting with hydroxyl and nitrogen oxides at rather high temperature and sunlight, leads to ozone formation. CO and CH4 are slowly oxidized in the atmosphere and cause an increase in global and regional background ozone. However, the oxidation of some VOCs occurs during daylight hours and is accompanied by an increase in ozone concentration near VOCs sources, particularly in urban and industrial areas. The contribution of biogenic VOCs to ozone generation is estimated to be from 40 to 70% of the total contribution of all chemical ozone precursors in the troposphere [1], with isoprene playing the main role in ozone formation [2]. The impact of aromatic hydrocarbons to ozone formation is reported to be about 40% of the total ozone generation from the oxidation of anthropogenic VOCs [3]. In this study, the results of VOCs measurements (isoprene, benzene, toluene, phenol, styrene, xylene and propilbenzene) by proton mass spectrometry in different regions of Russia along the Trans-Siberian railway from Moscow to Vladivostok from TROICA-12 campaign on a mobile laboratory in summer 2008 are analyzed. It is shown that the TROICA-12 measurements were carried out mostly in moderately polluted (2≤NOx20 ppb) conditions ( 20 and 2% of measurements, correspondingly). The lower troposphere chemical regime in the campaign is found to be mainly NOx sensitive, both in rural and urban environments, with typical morning NMHC/NOx ratios being well above 20. Hence, ozone production rates are expected to be controlled by regional NOx emissions and their complex interplay with both

  13. Newly detected ozone-depleting substances in the atmosphere

    Science.gov (United States)

    Laube, Johannes C.; Newland, Mike J.; Hogan, Christopher; Brenninkmeijer, Carl A. M.; Fraser, Paul J.; Martinerie, Patricia; Oram, David E.; Reeves, Claire E.; Röckmann, Thomas; Schwander, Jakob; Witrant, Emmanuel; Sturges, William T.

    2014-04-01

    Ozone-depleting substances emitted through human activities cause large-scale damage to the stratospheric ozone layer, and influence global climate. Consequently, the production of many of these substances has been phased out; prominent examples are the chlorofluorocarbons (CFCs), and their intermediate replacements, the hydrochlorofluorocarbons (HCFCs). So far, seven types of CFC and six types of HCFC have been shown to contribute to stratospheric ozone destruction. Here, we report the detection and quantification of a further three CFCs and one HCFC. We analysed the composition of unpolluted air samples collected in Tasmania between 1978 and 2012, and extracted from deep firn snow in Greenland in 2008, using gas chromatography with mass spectrometric detection. Using the firn data, we show that all four compounds started to emerge in the atmosphere in the 1960s. Two of the compounds continue to accumulate in the atmosphere. We estimate that, before 2012, emissions of all four compounds combined amounted to more than 74,000 tonnes. This is small compared with peak emissions of other CFCs in the 1980s of more than one million tonnes each year. However, the reported emissions are clearly contrary to the intentions behind the Montreal Protocol, and raise questions about the sources of these gases.

  14. Ozone

    Energy Technology Data Exchange (ETDEWEB)

    1978-02-01

    A joint report published by the U.K., the U.S., and France has recommended that further research is needed to quantify the damage to the ozone layer caused by propellants and certain fertilizers. However, the report described the effects of supersonic air flights on the ozone layers as ''neglilgible'', stating that a fleet of up to 35 Concorde aircraft would account for a small fraction of 1% of ozone destruction. Meanwhile, the U.S. Food and Drug Administration has compelled manufacturers of aerosol hairspray, deodorant, or antiperspirant that use chlorofluorocarbon (CFC) gases as a propellant to carry the health warning that it may harm public health and the environment by reducing ozone in the upper atmosphere. This public health warning is the beginning of a program adopted by U.S. agencies to ban CFC aerosols from interstate commerce by Apr. 1979.

  15. Increase of ozone concentrations, its temperature sensitivity and the precursor factor in South China

    Directory of Open Access Journals (Sweden)

    Y. C. Lee

    2014-08-01

    Full Text Available Concerns have been raised about the possible connections between the local and regional photochemical problem and global warming. The current study assesses the trend of ozone in Hong Kong and the Pearl River Delta (PRD in South China and investigates the interannual changes of sensitivity of ozone to air temperature, as well as the trends in regional precursors. Results reveal, at the three monitoring sites from the mid-1990s to 2010, an increase in the mean ozone concentrations from 1.0 to 1.6 µg m−3 per year. The increase occurred in all seasons, with the highest rate in autumn. This is consistent with trends and temperature anomalies in the region. The increase in the sensitivity of ozone to temperature is clearly evident from the correlation between ozone (OMI [Ozone Monitoring Instrument] column amount and surface air temperature (from the Atmospheric Infrared Sounder displayed in the correlation maps for the PRD during the prominently high ozone period of July–September. It is observed to have increased from 2005 to 2010, the latter being the hottest year on record globally. To verify this temporal change in sensitivity, the ground-level trends of correlation coefficients/regression slopes are analysed. As expected, results reveal a statistically significant upward trend over a 14-year period (1997–2010. While the correlation revealed in the correlation maps is in agreement with the corresponding OMI ozone maps when juxtaposed, temperature sensitivity of surface ozone also shows an association with ozone concentration, with R=0.5. These characteristics of ozone sensitivity are believed to have adverse implications for the region. As shown by ground measurements and/or satellite analyses, the decrease in nitrogen oxides (NO2 and NOx in Hong Kong is not statistically significant while NO2 of the PRD has only very slightly changed. However, carbon dioxide has remarkably declined in the whole region. While these observations concerning

  16. Monitoring of the atmospheric ozone layer and natural ultraviolet radiation: Annual report 2011

    Energy Technology Data Exchange (ETDEWEB)

    Svendby, T.M.; Myhre, C.L.; Stebel, K.; Edvardsen, K; Orsolini, Y.; Dahlback, A.

    2012-07-01

    This is an annual report describing the activities and main results of the monitoring programme: Monitoring of the atmospheric ozone layer and natural ultraviolet radiation for 2011. 2011 was a year with generally low ozone values above Norway. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway seems now to have stabilized.(Author)

  17. Convection links biomass burning to increased tropical ozone: However, models will tend to overpredict O3

    Science.gov (United States)

    Chatfield, Robert B.; Delany, Anthony C.

    1990-10-01

    Biomass burning throughout the inhabited portions of the tropics generates precursors which lead to significant local atmospheric ozone pollution. Several simulations show how this smog could be only an easily observed, local manifestation of a much broader increase in tropospheric ozone. We illustrate basic processes with a one-dimensional time-dependent model that is closer to true meteorological motions than commonly used eddy diffusion models. Its application to a representative region of South America gives reasonable simulations of the local pollutants measured there. Three illustrative simulations indicate the importance of dilution, principally due to vertical transport, in increasing the efficiency of ozone production, possibly enough for high ozone to be apparent on a very large, intercontinental scale. In the first, cook-then-mix, simulation the nitrogen oxides and other burning-produced pollutants are confined to a persistently subsident fair weather boundary layer for several days, and the resultant ozone is found to have only a transient influence on the whole column of tropospheric ozone. In the second, mix-then-cook, simulation the effect of typical cumulonimbus convection, which vents an actively polluted boundary layer, is to make a persistent increase in the tropical ozone column. Such a broadly increased ozone column is observed over the the populated "continental" portion of the tropics. A third simulation averages all emission, transport, and deposition parameters, representing one column in a global tropospheric model that does not simulate individual weather events. This "oversmoothing" simulation produces 60% more ozone than observed or otherwise modeled. Qualitatively similar overprediction is suggested for all models which average significantly in time or space, as all need do. Clearly, simulating these O3 levels will depend sensitively on knowledge of the timing of emissions and transport.

  18. Study of modified atmosphere packaging on the quality of ozonated freeze-dried chicken meat.

    Science.gov (United States)

    Zouaghi, Ferdaous; Cantalejo, María J

    2016-09-01

    The objective of this study was to evaluate the effects of different modified atmosphere packaging (MAP) conditions on the physicochemical and sensory properties of ozonated freeze-dried chicken meat stored at 21±1°C for 28days. To this end, 14 MAP treatments were performed to obtain the most suitable packaging atmosphere. High concentrations of O2 in MAP promoted loss of redness and increased the pH values. Moreover, when the concentration of CO2 in MAP was more than 40%, high values of textural parameters and low scores of sensory hardness and chewiness were achieved. The 20%CO2/80%N2 gas combination was found to be the most effective treatment for best maintaining the physicochemical and sensory quality of ozonated dried chicken samples similar to that of raw meat. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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).

  20. The role of ozone atmosphere-snow gas exchange on polar, boundaru-layer tropospheric ozone - a review sensitivity analysis

    NARCIS (Netherlands)

    Helmig, D.; Ganzeveld, L.N.; Butler, T.; Oltmans, S.

    2007-01-01

    Recent research on snowpack processes and atmosphere-snow gas exchange has demonstrated that chemical and physical interactions between the snowpack and the overlaying atmosphere have a substantial impact on the composition of the lower troposphere. These observations also imply that ozone

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

    Science.gov (United States)

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

    2017-05-01

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

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

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

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

  3. Tropospheric Ozone Changes, Radiative Forcing and Attribution to Emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    Science.gov (United States)

    Stevenson, D.S.; Young, P.J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; hide

    2013-01-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (+/-1 standard deviation) in RFs of +/-17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of +/-10 percent. Applying two different tropopause definitions gives differences in RFs of +/-3 percent. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of +/-30 percent for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44+/-12 percent), nitrogen oxides (31 +/- 9 percent), carbon monoxide (15 +/- 3 percent) and non-methane volatile organic compounds (9 +/- 2 percent); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m(-2) DU(-1), a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m(-2); relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some

  4. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP

    Directory of Open Access Journals (Sweden)

    D. S. Stevenson

    2013-03-01

    Full Text Available Ozone (O3 from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP has been used to calculate tropospheric ozone radiative forcings (RFs. All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750 to present-day (2010 tropospheric ozone RF of 410 mW m−2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation in RFs of ±17%. Three different radiation schemes were used – we find differences in RFs between schemes (for the same ozone fields of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44±12%, nitrogen oxides (31 ± 9%, carbon monoxide (15 ± 3% and non-methane volatile organic compounds (9 ± 2%; earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m−2 DU−1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m−2; relative to 1750 for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5 of 350, 420, 370 and 460 (in 2030, and 200, 300, 280 and 600 (in 2100. Models show some coherent responses of ozone to climate change

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

    Science.gov (United States)

    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

  6. Kudzu (Pueraria montana) invasion doubles emissions of nitric oxide and increases ozone pollution

    OpenAIRE

    Hickman, Jonathan E.; Wu, Shiliang; Mickley, Loretta J.; Lerdau, Manuel T.

    2010-01-01

    The nitrogen-fixing legume kudzu (Pueraria montana) is a widespread invasive plant in the southeastern United States with physiological traits that may lead to important impacts on ecosystems and the atmosphere. Its spread has the potential to raise ozone levels in the region by increasing nitric oxide (NO) emissions from soils as a consequence of increasing nitrogen (N) inputs and cycling in soils. We studied the effects of kudzu invasions on soils and trace N gas emissions at three sites in...

  7. Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

    Energy Technology Data Exchange (ETDEWEB)

    Domagal-Goldman, Shawn D. [Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S., E-mail: shawn.goldman@nasa.gov [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States)

    2014-09-10

    The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

  8. 2011 Arctic ozone depletion as seen by ESA-ENVISAT Atmospheric-Chemistry sensors

    Science.gov (United States)

    Brizzi, G.; Niro, F.; Saavedra de Miguel, L.; Dehn, A.; Scarpino, G.; Fehr, T.; von Kuhlmann, R.

    2011-12-01

    Three Atmospheric-Chemistry sensors on-board the ENVISAT satellite (GOMOS, MIPAS, and SCIAMACHY) sound the Earth's atmosphere since about nine years and provide to the science community three separated, but complementary data sets of the most interesting atmospheric trace gases. These extended and coherent data sets, generated with ESA operational processors, give a historical overview over seasonal and long-term trends of geophysical parameters and allow investigating major atmospheric phenomena and natural events. During March 2011, ESA's satellite ENVISAT detected the severe ozone depletion above the Euro-Atlantic sector of the Northern Hemisphere. This record-breaking loss for the ozone layer over the North Pole was mainly caused by unusual polar vortex conditions characterized by very low temperatures in the Arctic stratosphere. This paper presents the chemical ozone depletion over the Arctic regions as detected by SCIAMACHY, MIPAS and GOMOS during spring of 2011. Global maps of total ozone column and vertical ozone profiles along the mission's lifetime clearly show the unprecedented Arctic ozone loss for 2011 with the subsequent migration of ozone depleted air masses towards lower latitudes. ENVISAT's atmospheric measurements reveal changes in the composition of the ozone-related chemical species and permit to point out the chemical correlations of the ozone distribution with nitrogen and chlorine compounds and with the evolution of stratospheric temperatures. The synergistic use of ESA operational data sets from the three instruments allows to closely monitor the occurrence and extension of seasonal ozone depletion events, and to draw a comprehensive picture of all chemistry processes involved in the full atmospheric range.

  9. Potential Vorticity based parameterization for specification of Upper troposphere/lower stratosphere ozone in atmospheric models

    Data.gov (United States)

    U.S. Environmental Protection Agency — Potential Vorticity based parameterization for specification of Upper troposphere/lower stratosphere ozone in atmospheric models - the data set consists of 3D O3...

  10. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure

    Science.gov (United States)

    Duten, X.; Redolfi, M.; Aggadi, N.; Vega, A.; Hassouni, K.

    2011-10-01

    This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.

  11. Climate change and atmospheric chemistry: how will the stratospheric ozone layer develop?

    Science.gov (United States)

    Dameris, Martin

    2010-10-25

    The discovery of the ozone hole over Antarctica in 1985 was a surprise for science. For a few years the reasons of the ozone hole was speculated about. Soon it was obvious that predominant meteorological conditions led to a specific situation developing in this part of the atmosphere: Very low temperatures initiate chemical processes that at the end cause extreme ozone depletion at altitudes of between about 15 and 30 km. So-called polar stratospheric clouds play a key role. Such clouds develop at temperatures below about 195 K. Heterogeneous chemical reactions on cloud particles initiate the destruction of ozone molecules. The future evolution of the ozone layer will not only depend on the further development of concentrations of ozone-depleting substances, but also significantly on climate change.

  12. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    Science.gov (United States)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  13. Chemical pathway analysis of the Martian atmosphere: The formation and destruction of ozone

    Science.gov (United States)

    Boxe, C.; Stock, J.; Lehmann, R.; Grenfell, L.; Patzer, A.; Rauer, H.; Yung, Y. L.

    2014-12-01

    Ozone is a species of major importance in the Martian atmosphere e.g. since it is involved in the stabilization of Mars' major atmospheric constituent carbon dioxide. Below XX km altitude, ozone acts as an atomic oxygen source, which is produced by photolysis and oxidizes carbon monoxide via catalytic cycles involving odd hydrogen (HOx=H+OH+HO2). Originating mainly from H2O photolysis, odd hydrogen destroys ozone resulting in the observed anti-correlation between water vapor and ozone. Compared with species from the HOx-family, ozone is relatively easy to detect by e.g. UV spectroscopy or IR heterodyne spectroscopy. Similar to carbon dioxide, the concentration of ozone can be critically influenced by chemical trace species acting as catalysts in chemical pathways. The identification of such chemical pathways in complex reaction networks and the quantification of their contribution is in general challenging. Therefore, we use an automated computer algorithm (PAP - Pathway Analysis Program), which is specifically designed to address such problems. In this work, we apply the PAP-algorithm to the results of the newly updated JPL/Caltech photochemical column model of the Martian atmosphere in order to investigate the Martian atmospheric ozone photochemistry. The efficiencies of individual ozone formation and destruction pathways are calculated for different atmospheric heights, by applying the algorithm to each vertical layer of the column model in turn. The results of our investigations suggest that ozone is primarily produced by a Chapman-like mechanism, whereby atomic oxygen is produced by carbon dioxide photolysis instead of molecular oxygen photolysis. In the ozone layer at approximately 40 km altitude, ozone formation is chiefly dominated by a chemical pathway where atomic oxygen is supplied by vertical transport. Ozone consumption pathways involving ozone photolysis are most efficient except for a layer around 40 km altitude where the reaction between ozone and

  14. Newly detected ozone-depleting substances in the atmosphere

    NARCIS (Netherlands)

    Laube, Johannes C.; Newland, Mike J.; Hogan, Christopher; Brenninkmeijer, Carl A M; Fraser, Paul J.; Martinerie, Patricia; Oram, David E.; Reeves, Claire E.; Röckmann, Thomas|info:eu-repo/dai/nl/304838233; Schwander, Jakob; Witrant, Emmanuel; Sturges, William T.

    2014-01-01

    Ozone-depleting substances emitted through human activities cause large-scale damage to the stratospheric ozone layer, and influence global climate. Consequently, the production of many of these substances has been phased out; prominent examples are the chlorofluorocarbons (CFCs), and their

  15. Sensitivity of the Reaction Mechanism of the Ozone Depletion Events during the Arctic Spring on the Initial Atmospheric Composition of the Troposphere

    Directory of Open Access Journals (Sweden)

    Le Cao

    2016-09-01

    Full Text Available Ozone depletion events (ODEs during the Arctic spring have been investigated since the 1980s. It was found that the depletion of ozone is highly associated with the release of halogens, especially bromine containing compounds. These compounds originate from various substrates such as the ice/snow-covered surfaces in Arctic. In the present study, the dependence of the mixing ratios of ozone and principal bromine species during ODEs on the initial composition of the Arctic atmospheric boundary layer was investigated by using a concentration sensitivity analysis. This analysis was performed by implementing a reaction mechanism representing the ozone depletion and halogen release in the box model KINAL (KInetic aNALysis of reaction mechanics. The ratios between the relative change of the mixing ratios of particular species such as ozone and the variation in the initial concentration of each atmospheric component were calculated, which indicate the relative importance of each initial species in the chemical kinetic system. The results of the computations show that the impact of various chemical species is different for ozone and bromine containing compounds during the depletion of ozone. It was found that CH3CHO critically controls the time scale of the complete removal of ozone. However, the rate of the ozone loss and the maximum values of bromine species are only slightly influenced by the initial value of CH3CHO. In addition, according to the concentration sensitivity analysis, the reduction of initial Br2 was found to cause a significant retardant of the ODE while the initial mixing ratio of HBr exerts minor influence on both ozone and bromine species. In addition, it is also interesting to note that the increase of C2H2 would significantly raise the amount of HOBr and Br in the atmosphere while the ozone depletion is hardly changed.

  16. Atmospheric Ozone Profiles During Vasylkiv Oil Burning Episode

    Science.gov (United States)

    Shavrina, A.; Veles, A.; Milinevsky, G.; Grytsai, A.; Liptuga, A.; Kyslyi, V.; Romanyuk, Ya.

    Ground-based Fourier Transform Infrared spectrometer (FTIR) observations have been used for study stratosphere/troposphere ozone vertical distribution during Vasylkiv (near Kyiv, Ukraine) incident of petroleum storage burning in June 8-14, 2015.

  17. Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

    Science.gov (United States)

    Hopkins, Frances; Bell, Thomas; Yang, Mingxi

    2017-04-01

    Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

  18. Plant volatile organic compounds (VOCs) in ozone (O3) polluted atmospheres: the ecological effects.

    Science.gov (United States)

    Pinto, Delia M; Blande, James D; Souza, Silvia R; Nerg, Anne-Marja; Holopainen, Jarmo K

    2010-01-01

    Tropospheric ozone (O3) is an important secondary air pollutant formed as a result of photochemical reactions between primary pollutants, such as nitrogen oxides (NOx), and volatile organic compounds (VOCs). O3 concentrations in the lower atmosphere (troposphere) are predicted to continue increasing as a result of anthropogenic activity, which will impact strongly on wild and cultivated plants. O3 affects photosynthesis and induces the development of visible foliar injuries, which are the result of genetically controlled programmed cell death. It also activates many plant defense responses, including the emission of phytogenic VOCs. Plant emitted VOCs play a role in many eco-physiological functions. Besides protecting the plant from abiotic stresses (high temperatures and oxidative stress) and biotic stressors (competing plants, micro- and macroorganisms), they drive multitrophic interactions between plants, herbivores and their natural enemies e.g., predators and parasitoids as well as interactions between plants (plant-to-plant communication). In addition, VOCs have an important role in atmospheric chemistry. They are O3 precursors, but at the same time are readily oxidized by O3, thus resulting in a series of new compounds that include secondary organic aerosols (SOAs). Here, we review the effects of O3 on plants and their VOC emissions. We also review the state of current knowledge on the effects of ozone on ecological interactions based on VOC signaling, and propose further research directions.

  19. Will climate change increase ozone depletion from low-energy-electron precipitation?

    Directory of Open Access Journals (Sweden)

    A. J. G. Baumgaertner

    2010-10-01

    Full Text Available We investigate the effects of a strengthened stratospheric/mesospheric residual circulation on the transport of nitric oxide (NO produced by energetic particle precipitation. During periods of high geomagnetic activity, energetic electron precipitation (EEP is responsible for winter time ozone loss in the polar middle atmosphere between 1 and 6 hPa. However, as climate change is expected to increase the strength of the Brewer-Dobson circulation including extratropical downwelling, the enhancements of EEP NOx concentrations are expected to be transported to lower altitudes in extratropical regions, becoming more significant in the ozone budget. Changes in the mesospheric residual circulation are also considered. We use simulations with the chemistry climate model system EMAC to compare present day effects of EEP NOx with expected effects in a climate change scenario for the year 2100. In years of strong geomagnetic activity, similar to that observed in 2003, an additional polar ozone loss of up to 0.4 μmol/mol at 5 hPa is found in the Southern Hemisphere. However, this would be approximately compensated by an ozone enhancement originating from a stronger poleward transport of ozone from lower latitudes caused by a strengthened Brewer-Dobson circulation, as well as by slower photochemical ozone loss reactions in a stratosphere cooled by risen greenhouse gas concentrations. In the Northern Hemisphere the EEP NOx effect appears to lose importance due to the different nature of the climate-change induced circulation changes.

  20. 40 CFR Appendix D to Part 50 - Measurement Principle and Calibration Procedure for the Measurement of Ozone in the Atmosphere

    Science.gov (United States)

    2010-07-01

    ... Reference 8. 3. Apparatus. A complete UV calibration system consists of an ozone generator, an output port... necessary to meet the output stability and photometer precision requirements. 3.3 Ozone generator. Device... Procedure for the Measurement of Ozone in the Atmosphere D Appendix D to Part 50 Protection of Environment...

  1. Langley Mobile Ozone Lidar: Ozone and Aerosol Atmospheric Profiling for Air Quality Research

    Science.gov (United States)

    De Young, Russell; Carrion, William; Ganoe, Rene; Pliutau, Denis; Gronoff, Guillaume; Berkoff, Timothy; Kuang, Shi

    2017-01-01

    The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2 mJ/pulse 0.2 mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

  2. (Sub)nanosecond transient plasma for atmospheric plasma processing experiments: application to ozone generation and NO removal

    Science.gov (United States)

    Huiskamp, T.; Hoeben, W. F. L. M.; Beckers, F. J. C. M.; van Heesch, E. J. M.; Pemen, A. J. M.

    2017-10-01

    In this paper we use a (sub)nanosecond high-voltage pulse source (2-9 ns pulses with 0.4 ns rise time) to generate streamer plasma in a wire-cylinder reactor and apply it to two atmospheric plasma processing applications: ozone generation and NO removal. We will investigate what pulse parameters result in the highest plasma processing yields. The results show that for ozone generation, secondary-streamer effects appear to have a slight influence on the ozone yield: if the pulse duration increases and/or the voltage increases in such a way that streamers can start to cross the gap in the reactor, the ozone yields decrease. Furthermore, for NO removal, we see a similar effect of pulse duration and applied voltage as for the ozone generation, but the effect of the pulse duration is slightly different: long pulses result in the highest NO-removal yield. However, the NO-removal process is fundamentally different: besides removing NO, the plasma also produces NO and this production is more pronounced in the primary-streamer phase, which is why the pulse polarity has almost no influence on the NO-removal yield (only on the by-product formation). Moreover, the rise time of the pulses has a much more significant effect on ozone generation and NO removal than the pulse duration: a long rise time results in a lower enhanced electric field at the streamer heads, which consequently reduces the production of radicals required for ozone generation and NO removal, and decreases the streamer volume. Consequently, the resulting ozone yields and NO-removal yields are lower. Finally, the main conclusion is that the plasma generated with our nanosecond pulses is very efficient for ozone generation and NO removal, achieving yields as high as 175 g · kWh-1 for ozone generation and 2.5 mol · kWh-1 (or 14.9 eV per NO molecule) for NO removal.

  3. Study of total column atmospheric aerosol optical depth, ozone and ...

    Indian Academy of Sciences (India)

    Extensive observations of the columnar aerosol optical depth (AOD), total column ozone (TCO) and precipitable water content (PWC) have been carried out using the on-line, multi-band solar radiometers onboard ORV Sagar Kanya (Cruise#SK 147B) over Bay of Bengal during 11th-28th August 1999. Aerosol optical and ...

  4. Study of total column atmospheric aerosol optical depth, ozone and ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    total column ozone (TCO) and precipitable water content (PWC) have been carried out using the on-line, multi-band solar radiometers onboard ORV Sagar Kanya (Cruise # SK 147B) over Bay of Bengal during 11th–28th August 1999. Aerosol optical and physical properties (optical depth and angstrom parameter) have ...

  5. The role and importance of ozone for atmospheric chemistry and methods for measuring its concentration

    Directory of Open Access Journals (Sweden)

    Marković Dragan M.

    2003-01-01

    Full Text Available Depending on where ozone resides, it can protect or harm life on Earth. The thin layer of ozone that surrounds Earth acts as a shield protecting the planet from irradiation by UV light. When it is close to the planet's surface, ozone is a powerful photochemical oxidant that damage, icons frescos, museum exhibits, rubber, plastic and all plant and animal life. Besides the basic properties of some methods for determining the ozone concentration in working and living conditions, this paper presents a detailed description of the electrochemical method. The basic properties of the electrochemical method are used in the construction of mobile equipment for determining the sum of oxidants in the atmosphere. The equipment was used for testing the determination of the ozone concentration in working rooms, where the concentration was at a high level and caused by UV radiation or electrostatic discharge. According to the obtained results, it can be concluded that this equipment for determining the ozone concentration in the atmosphere is very powerful and reproducible in measurements.

  6. Ozone, water vapor, and temperature anomalies associated with atmospheric blocking events over Eastern Europe in spring - summer 2010

    Science.gov (United States)

    Sitnov, S. A.; Mokhov, I. I.; Lupo, A. R.

    2017-09-01

    Using data from the AIRS satellite instrument (V6, L3), ozone, water vapor (WV), and temperature anomalies associated with the relatively short spring atmospheric blocking event and anomalously prolonged summer block over European Russia (ER) in 2010 are analyzed. Within the domain of the blocking anticyclones, negative total column ozone (TCO) anomalies and positive total column water vapor (TCWV) anomalies reaching the values of -25 and -32 Dobson Units (DU) and 10 and 11 kg m-2 during the spring and summer blocks are observed, respectively. Conversely, within the regions adjacent to the anticyclones to the west and east, positive TCO anomalies (77 and 45 DU) and negative TCWV anomalies (-3 and -4 kg m-2) are found. These TCO and TCWV anomalies are conditioned by the regional atmospheric circulation associated with the strong omega-type blocking. The TCO deficit and TCWV surplus within the atmospheric blocking domain are explained primarily by the poleward advection of subtropical air with low TCO and high TCWV content and tropopause uplift. The TCO and TCWV anomalies are also associated with quasi-stationary Rossby wave trains that accompanied these blocking events. An analysis of the anomaly vertical structure shows that the marked TCO decrease is primarily due to the lower stratospheric ozone decrease, while the strong TCWV increase is mainly the result of an increase of lower tropospheric WV content. The possible role of photochemical ozone destruction in the lower stratosphere due to WV advection within the blocked regions is also discussed. Vertical profiles of the thermal anomalies during both atmospheric blocking events reveal dipole-like structures characterized by positive temperature anomalies in the troposphere and negative anomalies in the lower stratosphere.

  7. Electrolyte effects on aqueous atmospheric oxidation of sulphur dioxide by ozone

    Energy Technology Data Exchange (ETDEWEB)

    Lagrange, J.; Pallares, C.; Lagrange, P. [CNRS, Strasbourg (France)

    1994-07-01

    The kinetics of sulphur(IV) oxidation by ozone in an aqueous solution were studied in various supporting electrolytes (NaClO4, NaCl, NH4ClO4, Na2SO4), using the stopped flow method. The rare data in perchlorate medium (chosen as reference electrolyte) are empirically correlated by the following expression: r = -d(O3)/dt = K(O3)(S(IV))(H(+))(exp -1/2). For each supporting electrolyte studied, the rate constant varies linearly with the ionic strength. The value of the rate constant is extrapolated to zero ionic strength. The rate constants are shown to be higher mainly when ammonium chloride and sodium sulphate are added to the solution. The effect of temperature is studied between 13 and 28 C. The reaction rate is unaffected by the trace presence of metal ion (Mm(2+), Fe(2+), Cu(2+), Fe(3+), Cr(3+)). The rate of oxidation is dissolved SO2 by O3, in water droplets under atmospheric conditions, is calculated as a function of (H(+)) and compared to the oxidation by H2O2. At zero ionic strength the ozone reaction becomes faster than hydrogen peroxide reaction above -log (H(+)) = 4.70. This effect appears at higher H(+) concentration when the ionic strength increases (-log (H(+)) = 3 in 4 mol/L NaCl or 2 mol/L Na2SO4).

  8. Ozone

    Science.gov (United States)

    ... particularly vulnerable to the respiratory effects of ozone. Results from an NIEHS-funded study show that children who played three or more outdoor sports in areas with high ozone concentrations were more ...

  9. Comparative scenario study of tropospheric ozone climate interactions using a global model. A 1% global increase rate, the IS92a IPCC scenario and a simplified aircraft traffic increase scenario

    Energy Technology Data Exchange (ETDEWEB)

    Chalita, S. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Service d`Aeronomie; Le Treut, H. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Lab. de Meteorologie Dynamique

    1997-12-31

    Sensitivity studies have been made to establish the relationship between different scenarios of tropospheric ozone increase and radiative forcing. Some aspects of the ozone-climate interactions for past and future scenarios are investigated. These calculations employ IMAGES tropospheric ozone concentrations for a pre-industrial, present and future atmospheres. The averaged last 10 years of the 25-year seasonal integrations were analyzed. The results of this study are preliminary. Ozone forcing is basically different from the CO{sub 2} forcing, for its regional and temporal structured nature and for its rather weak intensity. (R.P.) 14 refs.

  10. Changes in stratospheric ozone.

    Science.gov (United States)

    Cicerone, R J

    1987-07-03

    The ozone layer in the upper atmosphere is a natural feature of the earth's environment. It performs several important functions, including shielding the earth from damaging solar ultraviolet radiation. Far from being static, ozone concentrations rise and fall under the forces of photochemical production, catalytic chemical destruction, and fluid dynamical transport. Human activities are projected to deplete substantially stratospheric ozone through anthropogenic increases in the global concentrations of key atmospheric chemicals. Human-induced perturbations may be occurring already.

  11. The impact of traffic emissions on atmospheric ozone and OH: results from QUANTIFY

    Directory of Open Access Journals (Sweden)

    P. Hoor

    2009-05-01

    Full Text Available To estimate the impact of emissions by road, aircraft and ship traffic on ozone and OH in the present-day atmosphere six different atmospheric chemistry models have been used. Based on newly developed global emission inventories for road, ship and aircraft emission data sets each model performed sensitivity simulations reducing the emissions of each transport sector by 5%.

    The model results indicate that on global annual average lower tropospheric ozone responds most sensitive to ship emissions (50.6%±10.9% of the total traffic induced perturbation, followed by road (36.7%±9.3% and aircraft exhausts (12.7%±2.9%, respectively. In the northern upper troposphere between 200–300 hPa at 30–60° N the maximum impact from road and ship are 93% and 73% of the maximum effect of aircraft, respectively. The latter is 0.185 ppbv for ozone (for the 5% case or 3.69 ppbv when scaling to 100%. On the global average the impact of road even dominates in the UTLS-region. The sensitivity of ozone formation per NOx molecule emitted is highest for aircraft exhausts.

    The local maximum effect of the summed traffic emissions on the ozone column predicted by the models is 0.2 DU and occurs over the northern subtropical Atlantic extending to central Europe. Below 800 hPa both ozone and OH respond most sensitively to ship emissions in the marine lower troposphere over the Atlantic. Based on the 5% perturbation the effect on ozone can exceed 0.6% close to the marine surface (global zonal mean which is 80% of the total traffic induced ozone perturbation. In the southern hemisphere ship emissions contribute relatively strongly to the total ozone perturbation by 60%–80% throughout the year.

    Methane lifetime changes against OH are affected strongest by ship emissions up to 0.21 (± 0.05%, followed by road (0.08 (±0.01% and air traffic (0.05 (± 0.02%.
    Based on the full scale ozone and methane perturbations positive radiative

  12. Productivity and community structure of ectomycorrhizal fungal sporocarps under increased atmospheric CO2 and O3

    Science.gov (United States)

    Carrie Andrew; Erik A. Lilleskov

    2009-01-01

    Sporocarp production is essential for ectomycorrhizal fungal recombination and dispersal, which influences fungal community dynamics. Increasing atmospheric carbon dioxide (CO2) and ozone (O3) affect host plant carbon gain and allocation, which may in turn influence ectomycorrhizal sporocarp production if the carbon...

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

    Science.gov (United States)

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

  14. Modeling coupled interactions of carbon, water, and ozone exchange between terrestrial ecosystems and the atmosphere

    Science.gov (United States)

    Ned Nikolova; Karl F. Zeller

    2003-01-01

    A new biophysical model (FORFLUX) is presented to study the simultaneous exchange of ozone, carbon dioxide, and water vapor between terrestrial ecosystems and the atmosphere. The model mechanistically couples all major processes controlling ecosystem flows trace gases and water implementing recent concepts in plant eco-physiology, micrometeorology, and soil hydrology....

  15. Kudzu (Pueraria montana) invasion doubles emissions of nitric oxide and increases ozone pollution.

    Science.gov (United States)

    Hickman, Jonathan E; Wu, Shiliang; Mickley, Loretta J; Lerdau, Manuel T

    2010-06-01

    The nitrogen-fixing legume kudzu (Pueraria montana) is a widespread invasive plant in the southeastern United States with physiological traits that may lead to important impacts on ecosystems and the atmosphere. Its spread has the potential to raise ozone levels in the region by increasing nitric oxide (NO) emissions from soils as a consequence of increasing nitrogen (N) inputs and cycling in soils. We studied the effects of kudzu invasions on soils and trace N gas emissions at three sites in Madison County, Georgia in 2007 and used the results to model the effects of kudzu invasion on regional air quality. We found that rates of net N mineralization increased by up to 1,000%, and net nitrification increased by up to 500% in invaded soils in Georgia. Nitric oxide emissions from invaded soils were more than 100% higher (2.81 vs. 1.24 ng NO-N cm(-2) h(-1)). We used the GEOS-Chem chemical transport model to evaluate the potential impact of kudzu invasion on regional atmospheric chemistry and air quality. In an extreme scenario, extensive kudzu invasion leads directly to an increase in the number of high ozone events (above 70 ppb) of up to 7 days each summer in some areas, up from 10 to 20 days in a control scenario with no kudzu invasion. These results establish a quantitative link between a biological invasion and ozone formation and suggest that in this extreme scenario, kudzu invasion can overcome some of the air quality benefits of legislative control.

  16. Ozone Atmospheric Pollution and Alzheimer's Disease: From Epidemiological Facts to Molecular Mechanisms.

    Science.gov (United States)

    Croze, Marine L; Zimmer, Luc

    2018-01-01

    Atmospheric pollution is a well-known environmental hazard, especially in developing countries where millions of people are exposed to airborne pollutant levels above safety standards. Accordingly, several epidemiological and animal studies confirmed its role in respiratory and cardiovascular pathologies and identified a strong link between ambient air pollution exposure and adverse health outcomes such as hospitalization and mortality. More recently, the potential deleterious effect of air pollution inhalation on the central nervous system was also investigated and mounting evidence supports a link between air pollution exposure and neurodegenerative pathologies, especially Alzheimer's disease (AD). The focus of this review is to highlight the possible link between ozone air pollution exposure and AD incidence. This review's approach will go from observational and epidemiological facts to the proposal of molecular mechanisms. First, epidemiological and postmortem human study data concerning residents of ozone-severely polluted megacities will be presented and discussed. Then, the more particular role of ozone air pollution in AD pathology will be described and evidenced by toxicological studies in rat or mouse with ozone pollution exposure only. The experimental paradigms used to reproduce in rodent the human exposure to ozone air pollution will be described. Finally, current insights into the molecular mechanisms through which ozone inhalation can affect the brain and play a role in AD development or progression will be recapitulated.

  17. Study of the superficial ozone concentrations in the atmosphere of Comunidad de Madrid using passive samplers

    Directory of Open Access Journals (Sweden)

    D. Galán Madruga

    2001-06-01

    Full Text Available The ozone is a secondary atmospheric pollutant which is generated for photochemical reactions of volatil organic compounds (VOC’s and nitrogen oxides (NOx. In Spain the ozone is a big problem as a consequence of the solar radiation to reach high levels. Exposure over a period of time to elevated ozone concentrations can cause damage in the public health and alterations in the vegetation.The aim of this study is to carry out the development and validation of a measurement method to let asses the superficial ozone levels in the Comunidad de Madrid, by identifing the zones more significants, where to measure with UV photometric monitors (automatics methods this pollutant and where the health and the vegetation can be affected. To such effect, passive samplers are used, which have glass fiber filters coated with a solution of sodium nitrite, potassium carbonate, glycerol and water. The nitrite ion in the presence of ozone is oxidized to nitrato ion, which it is extrated with ultrapure water and analyzed for ion chromatography, by seen proportional to the concentration existing in the sampling point.The results of validation from field tests indicate a excellent correlation between the passive and the automatic method.The higher superficial ozone concentrations are placed in rural zones, distanced of emission focus of primary pollutants (nitrogen oxides and volatil organic compounds... principally in direction soutwest and northwest of the Comunidad of Madrid.

  18. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    Science.gov (United States)

    Kuhn, U.; Ganzeveld, L.; Thielmann, A.; Dindorf, T.; Schebeske, G.; Welling, M.; Sciare, J.; Roberts, G.; Meixner, F. X.; Kesselmeier, J.; Lelieveld, J.; Kolle, O.; Ciccioli, P.; Lloyd, J.; Trentmann, J.; Artaxo, P.; Andreae, M. O.

    2010-10-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by concentrations of total aerosol number (CN) and cloud condensation nuclei (CCN), and by light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios within the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h-1. Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60-80% at 0.6% supersaturation), the CCN/CN ratios within the plume indicated that only a small fraction (16±12%) of the plume particles were CCN

  19. Impacts of Ozone-vegetation Interactions and Biogeochemical Feedbacks on Atmospheric Composition and Air Quality Under Climate Change

    Science.gov (United States)

    Sadeke, M.; Tai, A. P. K.; Lombardozzi, D.; Val Martin, M.

    2015-12-01

    Surface ozone pollution is one of the major environmental concerns due to its damaging effects on human and vegetation. One of the largest uncertainties of future surface ozone prediction comes from its interaction with vegetation under a changing climate. Ozone can be modulated by vegetation through, e.g., biogenic emissions, dry deposition and transpiration. These processes are in turn affected by chronic exposure to ozone via lowered photosynthesis rate and stomatal conductance. Both ozone and vegetation growth are expected to be altered by climate change. To better understand these climate-ozone-vegetation interactions and possible feedbacks on ozone itself via vegetation, we implement an online ozone-vegetation scheme [Lombardozzi et al., 2015] into the Community Earth System Model (CESM) with active atmospheric chemistry, climate and land surface components. Previous overestimation of surface ozone in eastern US, Canada and Europe is shown to be reduced by >8 ppb, reflecting improved model-observation comparison. Simulated surface ozone is lower by 3.7 ppb on average globally. Such reductions (and improvements) in simulated ozone are caused mainly by lower isoprene emission arising from reduced leaf area index in response to chronic ozone exposure. Effects via transpiration are also potentially significant but require better characterization. Such findings suggest that ozone-vegetation interaction may substantially alter future ozone simulations, especially under changing climate and ambient CO2 levels, which would further modulate ozone-vegetation interactions. Inclusion of such interactions in Earth system models is thus necessary to give more realistic estimation and prediction of surface ozone. This is crucial for better policy formulation regarding air quality, land use and climate change mitigation. Reference list: Lombardozzi, D., et al. "The Influence of Chronic Ozone Exposure on Global Carbon and Water Cycles." Journal of Climate 28.1 (2015): 292-305.

  20. Pre-industrial to End 21st Century Projections of Tropospheric Ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    Science.gov (United States)

    Young, P. J.; Archibald, A. T.; Bowman, K. W.; Lamarque, J.-F.; Naik, V.; Stevenson, D. S.; Tilmes, S.; Voulgarakis, A.; Wild, O.; Bergmann, D.; hide

    2013-01-01

    Present day tropospheric ozone and its changes between 1850 and 2100 are considered, analysing 15 global models that participated in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The ensemble mean compares well against present day observations. The seasonal cycle correlates well, except for some locations in the tropical upper troposphere. Most (75 %) of the models are encompassed with a range of global mean tropospheric ozone column estimates from satellite data, but there is a suggestion of a high bias in the Northern Hemisphere and a low bias in the Southern Hemisphere, which could indicate deficiencies with the ozone precursor emissions. Compared to the present day ensemble mean tropospheric ozone burden of 337+/-23 Tg, the ensemble mean burden for 1850 time slice is approx. 30% lower. Future changes were modelled using emissions and climate projections from four Representative Concentration Pathways (RCPs). Compared to 2000, the relative changes in the ensemble mean tropospheric ozone burden in 2030 (2100) for the different RCPs are: -4% (-16 %) for RCP2.6, 2% (-7%) for RCP4.5, 1% (-9%) for RCP6.0, and 7% (18 %) for RCP8.5. Model agreement on the magnitude of the change is greatest for larger changes. Reductions in most precursor emissions are common across the RCPs and drive ozone decreases in all but RCP8.5, where doubled methane and a 40-150% greater stratospheric influx (estimated from a subset of models) increase ozone. While models with a high ozone burden for the present day also have high ozone burdens for the other time slices, no model consistently predicts large or small ozone changes; i.e. the magnitudes of the burdens and burden changes do not appear to be related simply, and the models are sensitive to emissions and climate changes in different ways. Spatial patterns of ozone changes are well correlated across most models, but are notably different for models without time evolving stratospheric ozone concentrations

  1. Ozone injury increases infection of geranium leaves by Botrytis cinerea

    Energy Technology Data Exchange (ETDEWEB)

    Manning, W.J.; Feder, W.A.; Perkins, I.

    1970-04-01

    Detached and attached, inoculated and noninoculated, ozone-injured and noninjured leaves from the lower, middle, and terminal regions of plants of geranium cultivars Enchantress and White Mountain were observed for infection by Botrytis cinerea. Previous exposure to ozone did not appreciably influence the susceptibility of leaves of either geranium cultivar to infection by B. cinerea, unless there was visible ozone injury. Ozone-injured, necrotic tissues on older attached and detached geranium leaves of both cultivars served as infection courts for B. cinerea. 14 references, 1 table.

  2. Nuclear weapons tests and short-term effects on atmospheric ozone

    Science.gov (United States)

    Miller, A. J.; Krueger, A. J.; Prabhakara, C.; Hilsenrath, E.

    1974-01-01

    Observations made when Nimbus 4 passed over a nuclear cloud about three hours after the bomb exploded are presented. Infrared and BUV measurements indicated that the atmospheric ozone level in the area of cloud was significantly less than in areas directly north and south of the cloud. It is noted, however, that it is not possible to state definitively that the ozone depletion was caused by nitrogen oxides released in the nuclear weapons test, and that further observations must be made to clarify the situation.

  3. Nocturnal surface ozone enhancement over Portugal during winter: Influence of different atmospheric conditions

    KAUST Repository

    Kulkarni, Pavan S.

    2016-09-24

    Four distinct nocturnal surface ozone (NSO) enhancement events were observed, with NSO concentration exceeding 80μg/m3, at multiple ozone (O3) monitoring stations (32 sites) in January, November and December between year 2000–2010, in Portugal. The reasonable explanation for the observed bimodal pattern of surface ozone with enhanced NSO concentration during nighttime has to be transport processes, as the surface ozone production ceases at nighttime. Simultaneous measurements of O3 at multiple stations during the study period in Portugal suggest that horizontal advection alone cannot explain the observed NSO enhancement. Thus, detailed analysis of the atmospheric conditions, simulated with the Weather Research and Forecasting (WRF) model, were performed to evaluate the atmospheric mechanisms responsible for NSO enhancement in the region. Simulations revealed that each event occurred as a result of one or the combination of different atmospheric processes such as, passage of a cold front followed by a subsidence zone; passage of a moving surface trough, with associated strong horizontal wind speed and vertical shear; combination of vertical and horizontal transport at the synoptic scale; formation of a low level jet with associated vertical mixing below the jet stream. The study confirmed that large-scale flow pattern resulting in enhanced vertical mixing in the nocturnal boundary layer, plays a key role in the NSO enhancement events, which frequently occur over Portugal during winter months. © 2016 Elsevier Ltd

  4. On the unsteady decline of atmospheric CFC-11: Bumps in the road to ozone recovery or variations in atmospheric transport and/or loss?

    Science.gov (United States)

    Montzka, Stephen; Dutton, Geoff; Yu, Pengfei; Portmann, Bob; Ray, Eric; Daniel, John; Moore, Fred; Nance, David; Hall, Brad; Siso, Carolina; Miller, Ben; Mondeel, Debra; Kuijpers, Lambert; Hu, Lei; Elkins, James

    2017-04-01

    Atmospheric mole fractions of the ozone-depleting and greenhouse gas CFC-11 have declined since 1995 owing to global controls on production associated with the fully adjusted and amended Montreal Protocol on Substances that Deplete the Ozone Layer. From 2002 to 2012, CFC-11 mole fractions in both hemispheres decreased at a near-constant rate of 2.2 ± 0.2 ppt/yr. Assuming a constant atmospheric loss frequency, these results suggest that CFC-11 emissions did not decrease over this 11-yr period. This conclusion is difficult to reconcile with an idealized model of emissions being sustained by leaks from a shrinking reservoir of CFC-11 (reported global production has been negligible since 2007). Even more surprising, from 2013 to 2015 the atmospheric decline slowed appreciably (mean global rate was -1.3 ± 0.1 ppt/yr) and the hemispheric difference (N - S) increased by 50%. Here we consider the implications of these atmospheric changes. When analyzed with a simple 3-box model and constant loss frequency or a 3-D climate model (WACCM) with specified dynamics, the observations suggest global CFC-11 emissions in 2014-2015 that were 30% (15 Gg/yr) larger in 2014 and 2015 compared to the 2002-2012 mean. Are emissions of this globally controlled Class 1 ozone-depleting substance actually increasing despite global reported production being negligible for nearly a decade? Or do anomalies observed for multiple trace gases during these periods suggest significant changes in stratospheric loss and mixing processes that are not captured by global models using estimates of actual meteorology?

  5. Skill in forecasting extreme ozone pollution episodes with a global atmospheric chemistry model

    Science.gov (United States)

    Schnell, J. L.; Holmes, C. D.; Jangam, A.; Prather, M. J.

    2014-08-01

    From the ensemble of stations that monitor surface air quality over the United States and Europe, we identify extreme ozone pollution events and find that they occur predominantly in clustered, multiday episodes with spatial extents of more than 1000 km. Such scales are amenable to forecasting with current global atmospheric chemistry models. We develop an objective mapping algorithm that uses the heterogeneous observations of the individual surface sites to calculate surface ozone averaged over 1° by 1° grid cells, matching the resolution of a global model. Air quality extreme (AQX) events are identified locally as statistical extremes of the ozone climatology and not as air quality exceedances. With the University of California, Irvine chemistry-transport model (UCI CTM) we find there is skill in hindcasting these extreme episodes, and thus identify a new diagnostic using global chemistry-climate models (CCMs) to identify changes in the characteristics of extreme pollution episodes in a warming climate.

  6. From closing the atmospheric ozone hole to reducing climate change. Lessons learned.

    Science.gov (United States)

    Ewart, Gary W; Rom, William N; Braman, Sidney S; Pinkerton, Kent E

    2015-02-01

    Global warming presents U.S. and transnational leaders with enormous political and policy challenges. World leadership addressed a similar worldwide environmental challenge in the 1980s and 1990s when scientists advised that accelerating emission of man-made chlorofluorocarbons was depleting the ozone layer of the earth's atmosphere. The process that led to global agreement on reducing depletion of the ozone layer holds valuable lessons, and some ironies, for scientists and policy makers seeking now to address global climate change. By understanding the international treaty process, how science informed that process, and how the physician community played a constructive role in the transition away from commercial use of ozone-depleting gases three decades ago, environmental activists can better understand the challenges, opportunities, and potential solutions under current consideration in affecting global climate change.

  7. Atmospheric Volatile Organic Compounds and Ozone Creation Potential in an Urban Center of Southern Nigeria

    Directory of Open Access Journals (Sweden)

    Emmanuel Gbenga Olumayede

    2014-01-01

    Full Text Available The relative contribution of individual volatile organic compounds (VOC species to photochemical ozone formation depends on their atmospheric concentrations and their oxidation mechanism. In an attempt to evaluate the ozone creation potential of ambient VOCs captured in an urban settlement of Benin City, Nigeria, the VOCs concentrations data collected in field studies at nine measurement sites of different air quality in the city and a background site were analysed. Air samples were collected at human breathing height of 1.5 meters from ground level at each site. Active sampling method using the low volume sampling pump (Acuro, Drager, Lubeck, Germany was used to drawn the air into the tube; the absorbent was Chromosorb 106. The sampling periods were between May 2010 and June 2011; the period covered both dry and wet seasons. The adsorbed gases were desorbed using solvent extraction method with carbon disulphide as solvent. The extracted solutions were analyzed with gas chromatography and mass spectrometer. The observed concentrations of individual VOCs were determined and maximum incremental reactivity (MIR coefficient along with rate constants of VOC-OH reactions were applied to assess the ozone formation potential of individual VOC in the ambient atmosphere. Sixteen VOC species were observed at various sites with mixing height in decreasing order: toluene (5.82, mp-xylene (3.58, ethylbenzene (3.46, benzene (2.29, and n-butane (0.84. The ozone formation potential study revealed that, ranking by propyl-equivalent, the alkanes included in this study account for 58% of the total propyl-equivalent concentration. The total ozone creation potential in the atmosphere of the Benin City was calculated to be 281.1 µg/m3. A comparison of total ozone formation potential (OFP in our study with results obtained from other cities of the world revealed that the total concentration of ozone production in our study is threefold lower than the values reported

  8. Microwave complex for ground based ozone and thermal sounding of middle atmosphere

    Science.gov (United States)

    Shvetsov, Alexander; Krasil'nikov, Alexander; Kulikov, Mihail; Ryskin, Vitaly; Bolshakov, Oleg; Belikovich, Mihail; Mukhin, Dmitry; Karashtin, Dmitry; Fedoseev, Lev; Feigin, Alexander

    2013-04-01

    Description of the novel ground-based microwave complex for ozone and thermal sounding of middle atmosphere is presented. The instrument include two spectroradiometers operating in the frequency range 110.3-111.3 GHz (ozone line), and in the in the frequency range 52.5 - 54.5 GHz (edge of 5-mm molecular oxygen band), accordingly. The latter includes band slope and four resolved from the earth's surface relatively weak oxygen lines. Both spectroradiometers employ feed cone as antenna with half-power beam width approximately equal 4 degree. Two digital fast Fourier transform spectrometers developed by "Acqiris" are used for signal analysis in the intermediate frequency range 0.05 - 1 GHz with the effective resolution 61 KHz. Both spectroradiometers operate in total power mod with fast internal calibration that realize by electrically controlled noise generator on basis of Shottky barrier diodes. Noise temperature is approximately 3000 K for ozone spectroradiometer and 1400 K for thermometer. Novel method for retrieval vertical profiles of ozone and temperature from radiometric data is applied. The procedure is based on Bayesian approach to inverse problems which assumes a construction of probability distribution of the characteristics of retrieved profiles with taking into account measurement noise and available a priori information about possible distributions of ozone and temperature in the middle atmosphere. At the present time we carry out the experimental campaign aimed to simultaneous measurements temperature and ozone profile above Nizhny Novgorod, Russia. The work was done under support of the RFBR (projects 11-05-97050 and 12-05-00999)

  9. Shelf Life Determination of Fresh Blueberries (Vaccinium corymbosum) Stored under Controlled Atmosphere and Ozone.

    Science.gov (United States)

    Concha-Meyer, Anibal; Eifert, Joseph D; Williams, Robert C; Marcy, Joseph E; Welbaum, Gregory E

    2015-01-01

    Fresh blueberries are commonly stored and transported by refrigeration in controlled atmospheres to protect shelf life for long periods of storage. Ozone is an antimicrobial gas that can extend shelf life and protect fruit from microbial contamination. Shelf life of fresh highbush blueberries was determined over 10-day storage in isolated cabinets at 4°C or 12°C under different atmosphere conditions, including air (control); 5% O2 : 15% CO2 : 80% N2 (controlled atmosphere storage (CAS)); and ozone gas (O3) 4 ppm at 4°C or 2.5 ppm at 12°C, at high relative humidity (90-95%). Samples were evaluated for yeast and molds growth, weight loss, and firmness. CAS and O3 did not delay or inhibit yeast and molds growth in blueberries after 10 days at both temperatures. Fruit stored at 4°C showed lower weight loss values compared with 12°C. Blueberries stored under O3 atmosphere showed reduced weight loss at 12°C by day 10 and loss of firmness when compared to the other treatments. Low concentrations of ozone gas together with proper refrigeration temperature can help protect fresh blueberries quality during storage.

  10. Shelf Life Determination of Fresh Blueberries (Vaccinium corymbosum Stored under Controlled Atmosphere and Ozone

    Directory of Open Access Journals (Sweden)

    Anibal Concha-Meyer

    2015-01-01

    Full Text Available Fresh blueberries are commonly stored and transported by refrigeration in controlled atmospheres to protect shelf life for long periods of storage. Ozone is an antimicrobial gas that can extend shelf life and protect fruit from microbial contamination. Shelf life of fresh highbush blueberries was determined over 10-day storage in isolated cabinets at 4°C or 12°C under different atmosphere conditions, including air (control; 5% O2 : 15% CO2 : 80% N2 (controlled atmosphere storage (CAS; and ozone gas (O3 4 ppm at 4°C or 2.5 ppm at 12°C, at high relative humidity (90–95%. Samples were evaluated for yeast and molds growth, weight loss, and firmness. CAS and O3 did not delay or inhibit yeast and molds growth in blueberries after 10 days at both temperatures. Fruit stored at 4°C showed lower weight loss values compared with 12°C. Blueberries stored under O3 atmosphere showed reduced weight loss at 12°C by day 10 and loss of firmness when compared to the other treatments. Low concentrations of ozone gas together with proper refrigeration temperature can help protect fresh blueberries quality during storage.

  11. Middle-atmospheric Ozone and HCl anomalies during the polar stratospheric warming 2010 observed by JEM/SMILES

    Science.gov (United States)

    Esmaeili Mahani, M.; Kreyling, D.; Sagawa, H.; Murata, I.; Kasaba, Y.; Kasai, Y.

    2012-12-01

    In this study we focused on investigating ozone and HCl variations and anomalies in the middle atmosphere due to the Stratospheric Sudden Warming (SSW) event of Arctic winter 2009-2010 using JEM/SMILES data. HCl anomalies in evolution of a SSW have been studied for the first time. SSWs are dramatic events in the winter stratosphere of the Northern Hemisphere where the deceleration or reversal of the eastward winds is accompanied by an increase of temperature by several tens of degrees. The main cause of this phenomenon is known to be the interaction of zonal mean flow with upward propagating transient planetary waves from the troposphere in mid-winter leading to a vortex displacement or break down. SSWs are dynamical disturbances found to affect both dynamics and chemical compositions of the middle atmosphere still having several different atmospheric features and behaviors to be studied. The Superconducting sub-Millimeter Limb Emission Sounder (SMILES) is a highly sensitive radiometer to observe various atmospheric compositions from upper troposphere to the mesosphere. SMILES was developed by the Japanese Aerospace eXploration Agency (JAXA) and the National Institute of Communications and Technology (NICT) located at the Japanese Experiment Module (JEM) on board the International Space Station (ISS). From October 2009 to April 2010, SMILES has accurately measured the vertical distributions and the diurnal variations of for example ozone and HCl with the accuracy of less than 8% and 5% in the middle atmosphere respectively. By using SMILES data the SSW event of 2010 was confirmed on 25-January categorized as a major, vortex displacement warming. After the SSW, ozone values enhanced up to 15-20% in mid-stratosphere due to the meridional transport from lower latitudes and weakening of the polar vortex. The mesospheric ozone response will also be demonstrated and discussed. For HCl, the total increase of 10% in Upper Stratosphere Lower Mesosphere (USLM) before the

  12. Software for retrieving the ozone altitude profiles from data of atmospheric laser sensing

    Science.gov (United States)

    Nevzorov, Aleksey V.; Nevzorov, Aleksey A.; Romanovskii, Oleg A.

    2014-11-01

    In the report, we describe the software developed to retrieve the ozone altitude profiles from data of lidar measurements. The software is written in the programming language R#. At present, the C# language is one of the most advanced and modern programming languages. Many programs are written in this language since it is very easy to understand. The software makes it possible to calculate the ozone altitude profiles according to the method of differential absorption and scattering for three wavelength pairs 272/289 nm, 299/341 nm, and 308/353 nm. These wavelength pairs were chosen in view of the availability of lidar measurement data. The software has a suitable graphical interface, which displays all the steps of retrieving the ozone profiles in real time. The software makes it possible: to read off the lidar data and write the retrieval results in ASCII format; and smooth the lidar signals and the retrieval results with sliding averaging. The temperature correction of zone absorption coefficients is introduced in the software to reduce the retrieval errors. The aerosol backscattering is several times stronger than molecular backscattering when aerosol loading of the atmosphere is large; therefore, the retrieved ozone profile is substantially distorted when the scattering and attenuating properties of the atmosphere at the sensing wavelengths are not taken into consideration. An aerosol correction is introduced in this software. The latitudinally average seasonal model values of the altitudinal distribution of temperature and molecular backscattering coefficient for winter and summer are introduced in the software for the calculation.

  13. A Reference Model for Middle Atmosphere Ozone in 1992-1993

    Science.gov (United States)

    Wang, H. J.; Cunnold, D. M.; Froidevaux, L.; Russell, J. M.

    2002-01-01

    An ozone climatology for the period April 1992 to March 1993 and covering pressures from 0.1 to 100 hPa and from 80 deg N to 80 deg S is derived from satellite-based measurements by the Stratospheric Aerosol and Gas Experiment (SAGE), the Halogen Occultation Experiment (HALOE), and the Microwave Limb Sounder (MLS). At pressures less than 1 hPa, separate distributions are given for daytime and nighttime conditions. From 0.46 to 32 hPa the accuracy of the distribution is estimated to be 5%, and the precision is also approx. 5%. Estimates of atmospheric variability are provided on the basis of standard deviations of the measurements within months. Distributions of ozone monthly means and standard deviations are also given in a potential temperature, equivalent latitude coordinate system. This data set is included in the UARS reference atmosphere, and it is accessible through that web site.

  14. Effect of controlled atmosphere storage, modified atmosphere packaging and gaseous ozone treatment on the survival of Salmonella Enteritidis on cherry tomatoes.

    Science.gov (United States)

    Daş, Elif; Gürakan, G Candan; Bayindirli, Alev

    2006-08-01

    In recent years, outbreaks of infections associated with raw and minimally processed fruits and vegetables have been reported. The objective of this study was to analyse the growth/survival of Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes during passive modified atmosphere packaging (MAP), controlled atmosphere (CA) and to compare the results with those of air storage at 7 and 22 degrees C. During MAP, the gas composition equilibrated to 6% O2/4% CO2. CO2 level was maintained as 5% through the term of CA storage at 7 and 22 degrees C. The results demonstrate that S. Enteritidis can survive and/or grow during the storage of tomatoes depending on the location site of the pathogen on fruit, suspension cell density and storage temperature. During MAP, CA and air storage, S. Enteritidis with initial population of 7.0 log10 cfu/tomato survived on tomato surfaces with an approximate decrease of 4.0-5.0 log10 cfu/tomato in population within the storage period; however, in the case of initial population of 3.0 log10 cfu/tomato, cells died completely on day 4 during MAP storage and on day 6 during both CA and air storage. The death rate of S. Enteritidis on the surfaces of tomatoes that were stored in MAP was faster than that of stored in air and in CA. Storage temperature was effective on the survival of S. Enteritidis for the samples stored at ambient atmosphere; cells died completely on day 6 at 7 degrees C and on day 8 at 22 degrees C. Stem scars provided protective environments for Salmonella; an approximate increase of 1.0 log10 cfu/tomato in stem-scar population was observed during MAP, CA and air storage at 22 degrees C within the period of 20 days. Cells survived with no significant change in number at 7 degrees C. During the research, the effect of ozone treatment (5-30 mg/l ozone gas for 0-20 min) was also considered for surface sanitation before storage. Gaseous ozone treatment has bactericidal effect on S. Enteritidis, inoculated on

  15. Ozone reference models for CIRA. [COSPAR International Reference Atmosphere

    Science.gov (United States)

    Keating, G. M.; Young, D. F.; Pitts, M. C.

    1987-01-01

    The data bases and computational techniques used in recent models of the O3 distribution in the earth atmosphere are described, summarizing the results of ongoing efforts to define an O3 reference model for incorporation into CIRA. Consideration is given to the analysis of data from satellite instruments (Nimbus 7 LIMS, TOMS, and SBUV; SME UVS and IR; and AE-2 SAGE) to construct models of total column O3 and vertical O3 structure. The satellite-based model predictions are then compared with balloon, rocket, and umkehr measurements in extensive graphs: good agreement is demonstrated both among the satellite data sets and between satellite and nonsatellite data sets.

  16. Spatial and temporal variation of correlation between the Arctic total ozone and atmospheric temperature

    Science.gov (United States)

    Huang, Fuxiang; Ren, suling; Han, Shuangshuang; Zheng, xiangdong; Deng, xuejiao

    2017-04-01

    Daily total ozone and atmospheric temperature profile data in 2015 from the AIRS are used to investigate the spatial and temporal variation of the correlation between the Arctic atmospheric ozone and temperature. In the study, 11 lays atmospheric temperature profiles from the troposphere to the stratosphere are investigated. These layer heights are 20, 50, 70, 100, 200, 250, 300, 400, 500, 600 and 700 hPa respectively. The results show that a significant seasonal split exists in the correlation between the Arctic ozone and atmospheric temperature. Figure 1 shows the spatial and temporal variation of the coefficient between the atmospheric ozone and temperature at 50hPa. It can be seen from the figure that an obvious spatiotemporal difference exists in the correlation between the Arctic total ozone and atmospheric temperature in the lower stratosphere. First, the seasonal difference is very remarkable, which is shown as a significant positive correlation in most regions during winter and summer, while no correlation in the majority of regions occurs during spring and autumn, with a weak positive or negative correlation in a small number regions. Second, the spatial differences are also very obvious. The summer maximum correlation coefficient occurs in the Barents Sea and other locations at 0.8 and above, while the winter maximum occurs in the Baffin Bay area at 0.6 to 0.8. However, in a small number of regions, such as the land to the west of the Bering Strait in winter and the Arctic Ocean core area in summer, the correlation coefficients were unable to pass the significance test to show no correlation. At the same time, in spring and autumn, a positive correlation only occurs over a few low-latitude land areas, while over other Arctic areas, weak negative correlation exists. The differences in horizontal position are clearly related to the land-sea distribution, underlying surface characteristics, glacial melting, and other factors. In the troposphere, the ozone

  17. Integrated assessment modeling of atmospheric pollutants in the Southern Appalachian Mountains. Part I: hourly and seasonal ozone.

    Science.gov (United States)

    Boylan, James W; Odman, Mehmet T; Wilkinson, James G; Russell, Armistead G; Doty, Kevin G; Norris, William B; McNider, Richard T

    2005-07-01

    Recently, a comprehensive air quality modeling system was developed as part of the Southern Appalachians Mountains Initiative (SAMI) with the ability to simulate meteorology, emissions, ozone, size- and composition-resolved particulate matter, and pollutant deposition fluxes. As part of SAMI, the RAMS/EMS-95/URM-1ATM modeling system was used to evaluate potential emission control strategies to reduce atmospheric pollutant levels at Class I areas located in the Southern Appalachians Mountains. This article discusses the details of the ozone model performance and the methodology that was used to scale discrete episodic pollutant levels to seasonal and annual averages. The daily mean normalized bias and error for 1-hr and 8-hr ozone were within U.S. Environment Protection Agency guidance criteria for urban-scale modeling. The model typically showed a systematic overestimation for low ozone levels and an underestimation for high levels. Because SAMI was primarily interested in simulating the growing season ozone levels in Class I areas, daily and seasonal cumulative ozone exposure, as characterized by the W126 index, were also evaluated. The daily ozone W126 performance was not as good as the hourly ozone performance; however, the seasonal ozone W126 scaled up from daily values was within 17% of the observations at two typical Class I areas of the SAMI region. The overall ozone performance of the model was deemed acceptable for the purposes of SAMI's assessment.

  18. Quasi-biennial oscillation in atmospheric ozone, and its possible consequences for damaging UV-B radiation and for determination of long-term ozone trends

    Energy Technology Data Exchange (ETDEWEB)

    Gruzdev, A.N. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Atmospheric Physics

    1995-12-31

    The quasi-biennial oscillation (QBO) in ozone is supposed to be related to the QBO of zonal wind in the tropical stratosphere, with an approximate period of 29 months. Generally speaking, mechanisms of QBO-related effects in the extratropical atmosphere should depend on season and region, resulting in other periodicities (e.g., a 20-month periodicity) due to nonlinear interaction between the `pure` QBO and an annual cycle. Seasonal and regional dependences of QBO-related effects in ozone not only influence the regime of ozone variability itself, but can have important consequences, for example, for interannual changes in biologically active UV-B radiation and for determination of long-term ozone trends. This work is concerned with these problems

  19. Medical ozone increases methotrexate clinical response and improves cellular redox balance in patients with rheumatoid arthritis.

    Science.gov (United States)

    León Fernández, Olga Sonia; Viebahn-Haensler, Renate; Cabreja, Gilberto López; Espinosa, Irainis Serrano; Matos, Yanet Hernández; Roche, Liván Delgado; Santos, Beatriz Tamargo; Oru, Gabriel Takon; Polo Vega, Juan Carlos

    2016-10-15

    Medical ozone reduced inflammation, IL-1β, TNF-α mRNA levels and oxidative stress in PG/PS-induced arthritis in rats. The aim of this study was to investigate the medical ozone effects in patients with rheumatoid arthritis treated with methotrexate and methotrexate+ozone, and to compare between them. A randomized clinical study with 60 patients was performed, who were divided into two groups: one (n=30) treated with methotrexate (MTX), folic acid and Ibuprophen (MTX group) and the second group (n=30) received the same as the MTX group+medical ozone by rectal insufflation of the gas (MTX+ozone group). The clinical response of the patients was evaluated by comparing Disease Activity Score 28 (DAS28), Health Assessment Questionnaire Disability Index (HAQ-DI), Anti-Cyclic Citrullinated (Anti-CCP) levels, reactants of acute phase and biochemical markers of oxidative stress before and after 20 days of treatment. MTX+ozone reduced the activity of the disease while MTX merely showed a tendency to decrease the variables. Reactants of acute phase displayed a similar picture. MTX+ozone reduced Anti-CCP levels as well as increased antioxidant system, and decreased oxidative damage whereas MTX did not change. Glutathione correlated with all clinical variables just after MTX+ozone. MTX+ozone increased the MTX clinical response in patients with rheumatoid arthritis. No side effects were observed. These results suggest that ozone can increase the efficacy of MTX probably because both share common therapeutic targets. Medical ozone treatment is capable of being a complementary therapy in the treatment of rheumatoid arthritis. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. a Compact Dial LIDAR for Ground-Based Ozone Atmospheric Profiling Measurements

    Science.gov (United States)

    De Young, R.; Carrion, W.; Pliutau, D.; Ganoe, R. E.

    2013-12-01

    A compact differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone campaigns. This lidar will be integrated into the Air Quality lidar Network (AQLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver box with associated Licel photon counting and analog channels. The laser transmitter consist of a Coherent Evolution 30 TEM00 1-kHz diode pumped Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. A custom-designed Ce:LiCAF tunable UV laser has a wavelength range of 282 to 300-nm that is selectable between two or more wavelengths. The current wavelengths are online 286.4 nm and offline 293.1 nm. The 527-nm visible beam is transmitted into the atmosphere for aerosol measurements. The fourth harmonic 262 nm beam is split by a beamsplitter into two pump beams that pump each face of the Ce:LiCAF crystal. A short laser cavity consisting of a 60% reflective (1m radius of curvature) output mirror, a dispersive prism and a flat HR mirror is used to produce the UV wavelengths. In order to produce different wavelengths, the high-reflectivity rear mirror is mounted on a servo controlled galvanometer motor to allow rapid tuning between the on and offline ozone wavelengths. Typical laser results are 6.8-W at 527-nm, 800-mW at 262-nm and 130-mW at the UV transmitted wavelengths. The lidar receiver system consists of a receiver telescope with a 40-cm diameter parabolic mirror. A fiber optic cable transmits the received signal from the telescope to the receiver box, which houses the detectors. A separate one inch diameter telescope with PMT and filter is used to sample the very near field to allow

  1. Sensitivity and uncertainty analysis of atmospheric ozone photochemistry models. Final report, September 30, 1993--December 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Smith, G.P.

    1999-03-01

    The author has examined the kinetic reliability of ozone model predictions by computing direct first-order sensitivities of model species concentrations to input parameters: S{sub ij} = [dC{sub i}/C{sub i}]/[dk{sub j}/k{sub j}], where C{sub i} is the abundance of species i (e.g., ozone) and k{sub j} is the rate constant of step j (reaction, photolysis, or transport), for localized boxes from the LLNL 2-D diurnally averaged atmospheric model. An ozone sensitivity survey of boxes at altitudes of 10--55 km, 2--62N latitude, for spring, equinox, and winter is presented. Ozone sensitivities are used to evaluate the response of model predictions of ozone to input rate coefficient changes, to propagate laboratory rate uncertainties through the model, and to select processes and regions suited to more precise measurements. By including the local chemical feedbacks, the sensitivities quantify the important roles of oxygen and ozone photolysis, transport from the tropics, and the relation of key catalytic steps and cycles in regulating stratospheric ozone as a function of altitude, latitude, and season. A sensitivity-uncertainty analysis uses the sensitivity coefficients to propagate laboratory error bars in input photochemical parameters and estimate the net model uncertainties of predicted ozone in isolated boxes; it was applied to potential problems in the upper stratospheric ozone budget, and also highlights superior regions for model validation.

  2. Detecting recovery of the stratospheric ozone layer

    Science.gov (United States)

    Chipperfield, Martyn P.; Bekki, Slimane; Dhomse, Sandip; Harris, Neil R. P.; Hassler, Birgit; Hossaini, Ryan; Steinbrecht, Wolfgang; Thiéblemont, Rémi; Weber, Mark

    2017-09-01

    As a result of the 1987 Montreal Protocol and its amendments, the atmospheric loading of anthropogenic ozone-depleting substances is decreasing. Accordingly, the stratospheric ozone layer is expected to recover. However, short data records and atmospheric variability confound the search for early signs of recovery, and climate change is masking ozone recovery from ozone-depleting substances in some regions and will increasingly affect the extent of recovery. Here we discuss the nature and timescales of ozone recovery, and explore the extent to which it can be currently detected in different atmospheric regions.

  3. The importance of signals in the Doppler broadening range for middle-atmospheric microwave wind and ozone radiometry

    Science.gov (United States)

    Rüfenacht, Rolf; Kämpfer, Niklaus

    2017-09-01

    Doppler microwave radiometry is a novel technique for the measurement of horizontal wind profiles at altitudes between 10 and 0.03 hPa, where there is a substantial lack of observations. All wind radiometers currently in use rely on ground-based observations of microwave radiation emitted by atmospheric ozone. Besides the well-known primary ozone layer in the stratosphere a secondary ozone layer forms near 10-3 hPa during nighttime. We show that the emission signal of this secondary ozone layer cannot be neglected for the retrieval of mesospheric winds and that it can even alter nighttime ozone retrievals. However, the present study also demonstrates that with a reasonably adequate representation of the atmospheric reality in the mesopause region bias-free wind retrievals throughout the entire sensitive altitude range of the instruments can be achieved during day and nighttime. By applying the improved ozone a priori setup to real observation data the average zonal wind difference to models was substantially reduced and a realistic diurnal cycle was reproduced. Moreover the presence of the high nighttime mesopause ozone signal could enable future retrievals of mean winds beyond the altitude range dominated by pressure broadening.

  4. A Reference Model for Middle Atmosphere Ozone in 1992/1993: Differences from That of Keating et al (1996)

    Science.gov (United States)

    Wang, H. J.; Cunnold, D. M.

    2002-01-01

    Ozone distributions have been derived from recent satellite-based measurements by the Stratospheric Aerosol and Gas Experiment (SAGE), the Halogen Occultation Experiment (HALOE) and the Microwave Limb Sounder (MLS). An ozone distribution for the period April 1992 to March 1993 and covering pressures from 0.1 to 100 mb and from 80 deg N to 80 deg S is summarized. At pressures less than 1 mb, separate distributions are given for daytime and nighttime conditions. The resulting distributions extend to somewhat higher latitudes and lower altitudes than previous COSPAR reference atmosphere distributions for ozone. Differences versus the most recent COSPAR distribution by Keating et al are illustrated.

  5. Linear and regressive stochastic models for prediction of daily maximum ozone values at Mexico City atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, J. L [Instituto de Geofisica, UNAM, Mexico, D.F. (Mexico); Nava, M. M [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Gay, C [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico)

    2001-07-01

    We developed a procedure to forecast, with 2 or 3 hours, the daily maximum of surface ozone concentrations. It involves the adjustment of Autoregressive Integrated and Moving Average (ARIMA) models to daily ozone maximum concentrations at 10 monitoring atmospheric stations in Mexico City during one-year period. A one-day forecast is made and it is adjusted with the meteorological and solar radiation information acquired during the first 3 hours before the occurrence of the maximum value. The relative importance for forecasting of the history of the process and of meteorological conditions is evaluated. Finally an estimate of the daily probability of exceeding a given ozone level is made. [Spanish] Se aplica un procedimiento basado en la metodologia conocida como ARIMA, para predecir, con 2 o 3 horas de anticipacion, el valor maximo de la concentracion diaria de ozono. Esta basado en el calculo de autorregresiones y promedios moviles aplicados a los valores maximos de ozono superficial provenientes de 10 estaciones de monitoreo atmosferico en la Ciudad de Mexico y obtenidos durante un ano de muestreo. El pronostico para un dia se ajusta con la informacion meteorologica y de radiacion solar correspondiente a un periodo que antecede con al menos tres horas la ocurrencia esperada del valor maximo. Se compara la importancia relativa de la historia del proceso y de las condiciones meteorologicas previas para el pronostico. Finalmente se estima la probabilidad diaria de que un nivel normativo o preestablecido para contingencias de ozono sea rebasado.

  6. Evaluation of the production and the destruction of ozone in the lower atmosphere

    Science.gov (United States)

    Muramatsu, H.

    1994-01-01

    Observed surface ozone mixing ratio X(sub ob) is partitioned into two parts; X(sub tr), transported from the free troposphere and X(sub ch), chemically produced or destructed in the boundary layer. X(sub tr) is estimated from the ozone concentration in the free troposphere and the wind speed. The ozone in the free troposphere estimated from surface ozone observations is consistent with that of ozonesonde data. X(sub ch) is obtained from the difference between X(sub ob) and X(sub tr). X(sub tr) increases with wind speed, while X(sub ch) shows maximum at hourly wind speed of 1-2 m/s in the daytime. Contribution of X(sub tr) to X(sub ob) is larger than X(sub ch) except for a short period in summer. X(sub ch) is positive for April-October, but X(sub ch) can be negative in winter, showing the net chemical destruction in the boundary layer. X(sub ch) increases linearly with solar radiation, and is negative for daily global solar radiation below 8 MJ/sq m, which is about equal to the monthly mean in winter.

  7. Ozone Exposure Increases Circulating Stress Hormones and Lipid Metabolites in Humans

    Science.gov (United States)

    RATIONALE: Air pollution has been associated with increased prevalence of type 2 diabetes; however, the mechanisms remain unknown. We have shown that acute ozone exposure in rats induces release of stress hormones, hyperglycemia, leptinemia, and gluoose intolerance that are assoc...

  8. Plants, Pollution and Public Engagement with Atmospheric Chemistry: Sharing the TEMPO Story Through Ozone Garden Activities

    Science.gov (United States)

    Reilly, L. G.; Pippin, M. R.; Malick, E.; Summers, D.; Dussault, M. E.; Wright, E. A.; Skelly, J.

    2016-12-01

    What do a snap-bean plant and a future NASA satellite instrument named TEMPO have in common? They are both indicators of the quality of the air we breathe. Scientists, educators, and museum and student collaborators of the Tropospheric Emissions: Monitoring Pollution (TEMPO) instrument team are developing a program model to engage learners of all ages via public ozone garden exhibits and associated activities. TEMPO, an ultraviolet and visible spectroscopy instrument due for launch on a geostationary host satellite between 2019 and 2021, will scan North America hourly to measure the major elements in the tropospheric ozone chemistry cycle, providing near real-time data with high temporal and spatial resolution. The TEMPO mission provides a unique opportunity to share the story of the effects of air quality on living organisms. A public ozone garden exhibit affords an accessible way to understand atmospheric science through a connection with nature, while providing a visual representation of the impact of ozone pollution on living organisms. A prototype ozone garden exhibit was established at the Virginia Living Museum in partnership with NASA Langley, and has served as a site to formatively evaluate garden planting and exhibit display protocols, hands-on interpretive activities, and citizen science data collection protocols for learners as young as 3 to 10 as well as older adults. The fun and engaging activities, optimized for adult-child interaction in informal or free-choice learning environments, are aimed at developing foundational science skills such as observing, comparing, classifying, and collecting and making sense of data in the context of thinking about air quality - all NGSS-emphasized scientific practices, as well as key capabilities for future contributing members of the citizen science community. As the launch of TEMPO approaches, a major public engagement effort will include disseminating this ozone garden exhibit and program model to a network of

  9. Ozone uptake on glassy, semi-solid and liquid organic matter and the role of reactive oxygen intermediates in atmospheric aerosol chemistry.

    Science.gov (United States)

    Berkemeier, Thomas; Steimer, Sarah S; Krieger, Ulrich K; Peter, Thomas; Pöschl, Ulrich; Ammann, Markus; Shiraiwa, Manabu

    2016-05-14

    Heterogeneous and multiphase reactions of ozone are important pathways for chemical ageing of atmospheric organic aerosols. To demonstrate and quantify how moisture-induced phase changes can affect the gas uptake and chemical transformation of organic matter, we apply a kinetic multi-layer model to a comprehensive experimental data set of ozone uptake by shikimic acid. The bulk diffusion coefficients were determined to be 10(-12) cm(2) s(-1) for ozone and 10(-20) cm(2) s(-1) for shikimic acid under dry conditions, increasing by several orders of magnitude with increasing relative humidity (RH) due to phase changes from amorphous solid over semisolid to liquid. Consequently, the reactive uptake of ozone progresses through different kinetic regimes characterised by specific limiting processes and parameters. At high RH, ozone uptake is driven by reaction throughout the particle bulk; at low RH it is restricted to reaction near the particle surface and kinetically limited by slow diffusion and replenishment of unreacted organic molecules. Our results suggest that the chemical reaction mechanism involves long-lived reactive oxygen intermediates, likely primary ozonides or O atoms, which may provide a pathway for self-reaction and catalytic destruction of ozone at the surface. Slow diffusion and ozone destruction can effectively shield reactive organic molecules in the particle bulk from degradation. We discuss the potential non-orthogonality of kinetic parameters, and show how this problem can be solved by using comprehensive experimental data sets to constrain the kinetic model, providing mechanistic insights into the coupling of transport, phase changes, and chemical reactions of multiple species in complex systems.

  10. Ozone increases airway hyperreactivity and mucus hyperproduction in mice previously exposed to allergen

    DEFF Research Database (Denmark)

    Larsen, Søren T; Matsubara, Shigeki; McConville, Glen

    2010-01-01

    Acute exacerbations of asthma represent a common clinical problem with major economic impact. Air pollutants including ozone have been shown to contribute to asthma exacerbation, but the mechanisms underlying ozone-induced asthma exacerbation are only partially understood. The present study aimed...... with goblet-cell metaplasia. Even the lowest concentration of ozone tested, 100 ppb, which may be exceeded in urban environments and in the workplace, resulted in a significant increase in AHR, most prominent 24 h after exposure in the OVA-exposed mice....

  11. Ozone, Tropospheric

    Science.gov (United States)

    Fishman, Jack

    1995-01-01

    In the early part of the 20th century, ground-based and balloon-borne measurements discovered that most of atmosphere's ozone is located in the stratosphere with highest concentrations located between 15 and 30 km (9,3 and 18.6 miles). For a long time, it was believed that tropospheric ozone originated from the stratosphere and that most of it was destroyed by contact with the earth's surface. Ozone, O3, was known to be produced by the photo-dissociation of molecular oxygen, O2, a process that can only occur at wavelengths shorter than 242 nm. Because such short-wave-length radiation is present only in the stratosphere, no tropospheric ozone production is possible by this mechanism. In the 1940s, however, it became obvious that production of ozone was also taking place in the troposphere. The overall reaction mechanism was eventually identified by Arie Haagen-Smit of the California Institute of Technology, in highly polluted southern California. The copious emissions from the numerous cars driven there as a result of the mass migration to Los Angeles after World War 2 created the new unpleasant phenomenon of photochemical smog, the primary component of which is ozone. These high levels of ozone were injuring vegetable crops, causing women's nylons to run, and generating increasing respiratory and eye-irritation problems for the populace. Our knowledge of tropospheric ozone increased dramatically in the early 1950s as monitoring stations and search centers were established throughout southern California to see what could be done to combat this threat to human health and the environment.

  12. Forest-atmosphere exchange of ozone: sensitivity to very reactive biogenic VOC emissions and implications for in-canopy photochemistry

    Directory of Open Access Journals (Sweden)

    G. M. Wolfe

    2011-08-01

    Full Text Available Understanding the fate of ozone within and above forested environments is vital to assessing the anthropogenic impact on ecosystems and air quality at the urban-rural interface. Observed forest-atmosphere exchange of ozone is often much faster than explicable by stomatal uptake alone, suggesting the presence of additional ozone sinks within the canopy. Using the Chemistry of Atmosphere-Forest Exchange (CAFE model in conjunction with summer noontime observations from the 2007 Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX-2007, we explore the viability and implications of the hypothesis that ozonolysis of very reactive but yet unidentified biogenic volatile organic compounds (BVOC can influence the forest-atmosphere exchange of ozone. Non-stomatal processes typically generate 67 % of the observed ozone flux, but reactions of ozone with measured BVOC, including monoterpenes and sesquiterpenes, can account for only 2 % of this flux during the selected timeframe. By incorporating additional emissions and chemistry of a proxy for very reactive VOC (VRVOC that undergo rapid ozonolysis, we demonstrate that an in-canopy chemical ozone sink of ~2 × 108 molec cm−3 s−1 can close the ozone flux budget. Even in such a case, the 65 min chemical lifetime of ozone is much longer than the canopy residence time of ~2 min, highlighting that chemistry can influence reactive trace gas exchange even when it is "slow" relative to vertical mixing. This level of VRVOC ozonolysis could enhance OH and RO2 production by as much as 1 pptv s−1 and substantially alter their respective vertical profiles depending on the actual product yields. Reaction products would also contribute significantly to the oxidized VOC budget and, by extension, secondary organic aerosol mass. Given the potentially significant ramifications of a chemical ozone flux for both in-canopy chemistry and estimates of ozone

  13. Retrieving cloud, dust and ozone abundances in the Martian atmosphere using SPICAM/UV nadir spectra

    Science.gov (United States)

    Willame, Y.; Vandaele, A. C.; Depiesse, C.; Lefèvre, F.; Letocart, V.; Gillotay, D.; Montmessin, F.

    2017-08-01

    We present the retrieval algorithm developed to analyse nadir spectra from SPICAM/UV aboard Mars-Express. The purpose is to retrieve simultaneously several parameters of the Martian atmosphere and surface: the dust optical depth, the ozone total column, the cloud opacity and the surface albedo. The retrieval code couples the use of an existing complete radiative transfer code, an inversion method and a cloud detection algorithm. We describe the working principle of our algorithm and the parametrisation used to model the required absorption, scattering and reflection processes of the solar UV radiation that occur in the Martian atmosphere and at its surface. The retrieval method has been applied on 4 Martian years of SPICAM/UV data to obtain climatologies of the different quantities under investigation. An overview of the climatology is given for each species showing their seasonal and spatial distributions. The results show a good qualitative agreement with previous observations. Quantitative comparisons of the retrieved dust optical depths indicate generally larger values than previous studies. Possible shortcomings in the dust modelling (altitude profile) have been identified and may be part of the reason for this difference. The ozone results are found to be influenced by the presence of clouds. Preliminary quantitative comparisons show that our retrieved ozone columns are consistent with other results when no ice clouds are present, and are larger for the cases with clouds at high latitude. Sensitivity tests have also been performed showing that the use of other a priori assumptions such as the altitude distribution or some scattering properties can have an important impact on the retrieval.

  14. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    Directory of Open Access Journals (Sweden)

    U. Kuhn

    2010-10-01

    Full Text Available As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001 field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by concentrations of total aerosol number (CN and cloud condensation nuclei (CCN, and by light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios within the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h−1.

    Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60–80% at 0.6% supersaturation, the CCN/CN ratios within the

  15. Extreme events in total ozone over Arosa – Part 2: Fingerprints of atmospheric dynamics and chemistry and effects on mean values and long-term changes

    Directory of Open Access Journals (Sweden)

    H. E. Rieder

    2010-10-01

    Full Text Available In this study the frequency of days with extreme low (termed ELOs and extreme high (termed EHOs total ozone values and their influence on mean values and trends are analyzed for the world's longest total ozone record (Arosa, Switzerland. The results show (i an increase in ELOs and (ii a decrease in EHOs during the last decades and (iii that the overall trend during the 1970s and 1980s in total ozone is strongly dominated by changes in these extreme events. After removing the extremes, the time series shows a strongly reduced trend (reduction by a factor of 2.5 for trend in annual mean. Excursions in the frequency of extreme events reveal "fingerprints" of dynamical factors such as ENSO or NAO, and chemical factors, such as cold Arctic vortex ozone losses, as well as major volcanic eruptions of the 20th century (Gunung Agung, El Chichón, Mt. Pinatubo. Furthermore, atmospheric loading of ozone depleting substances leads to a continuous modification of column ozone in the Northern Hemisphere also with respect to extreme values (partly again in connection with polar vortex contributions. Application of extreme value theory allows the identification of many more such "fingerprints" than conventional time series analysis of annual and seasonal mean values. The analysis shows in particular the strong influence of dynamics, revealing that even moderate ENSO and NAO events have a discernible effect on total ozone. Overall the approach to extremal modelling provides new information on time series properties, variability, trends and the influence of dynamics and chemistry, complementing earlier analyses focusing only on monthly (or annual mean values.

  16. Increasing interannual and altitudinal ozone mixing ratios in the Catalan Pyrenees

    Science.gov (United States)

    Díaz-de-Quijano, Maria; Peñuelas, Josep; Ribas, Àngela

    2009-12-01

    Interannual, seasonal, daily and altitudinal patterns of tropospheric ozone mixing ratios, as well as ozone phytotoxicity and the relationship with NO x precursors and meteorological variables were monitored in the Central Catalan Pyrenees (Meranges valley and Forest of Guils) over a period of 5 years (2004-2008). Biweekly measurements using Radiello passive samplers were taken along two altitudinal transects comprised of thirteen stations ranging from 1040 to 2300 m a.s.l. Visual symptoms of ozone damage in Bel-W3 tobacco cultivars were evaluated biweekly for the first three years (2004-2006). High ozone mixing ratios, always above forest and vegetation protection AOT40 thresholds, were monitored every year. In the last 14 years, the AOT40 (Apr-Sept.) has increased significantly by 1047 μg m -3 h per year. Annual means of ozone mixing ratios ranged between 38 and 67 ppb v (38 and 74 ppb v during the warm period) at the highest site (2300 m) and increased at a rate of 5.1 ppb v year -1. The ozone mixing ratios were also on average 35-38% greater during the warm period and had a characteristic daily pattern with minimum values in the early morning, a rise during the morning and a decline overnight, that was less marked the higher the altitude. Whereas ozone mixing ratios increased significantly with altitude from 35 ppb v at 1040 m-56 ppb v at 2300 m (on average for 2004-2007 period), NO 2 mixing ratios decreased with altitude from 5.5 ppb v at 1040 m-1 ppb v at 2300 m. The analysis of meteorological variables and NO x values suggests that the ozone mainly originated from urban areas and was transported to high-mountain sites, remaining aloft in absence of NO. Ozone damage rates increased with altitude in response to increasing O 3 mixing ratios and a possible increase in O 3 uptake due to more favorable microclimatic conditions found at higher altitude, which confirms Bel-W3 as a suitable biomonitor for ozone concentrations during summer time. Compared to the

  17. Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection.

    Directory of Open Access Journals (Sweden)

    Matthew J Kesic

    Full Text Available Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs human airway trypsin-like protease (HAT and transmembrane protease, serine 2 (TMPRSS2, whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI. Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility.

  18. Recent measurements of the rates of ozone removal from the atmosphere by land surfaces. Paper 78-30. 5

    Energy Technology Data Exchange (ETDEWEB)

    Wesely, M.L.; Eastman, J.A.; Cook, D.R.; Hicks, B.B.

    1978-01-01

    The factors that control the uptake of airborne pollutants at land surfaces are highly varied and depend to a large extent on the chemical properties of the pollutant considered. Since ozone is not very soluble in pure water and is highly reactive with many substances, its uptake or destruction should be retarded by liquid water but enhanced by biological activity that produces substances susceptible to attack by ozone. It would appear that the variability in surface resistance to uptake of ozone is quite large due to the great natural variations in chemical composition, temperature, and water content of outdoor surfaces. Thus, the rates of removal of ozone from the atmosphere can be difficult to predict when flow over numerous kinds of surfaces is involved, such as in episodes of rather high ozone concentrations that occur over regional-scale distances (about 1000 km). The purpose of the present study is to examine measurements of ozone flux obtained directly by eddy-correlation techniques above certain agricultural surfaces, and to determine the surface properties, including estimated stomatal resistance, that are important in regulating the rate of ozone destruction at the surface. The two experimental sites were a large field of full-grown, healthy maize in Sangamon County near Springfield, Illinois, and the second site was a field of senescent maize in Rush County near Indianapolis, Indiana.

  19. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH+, MOH+, and MO2H+, respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH+ sharply decreased, that of MOH+ increased once and then decreased, and that of MO2H+ sharply increased until reaching a plateau. The signal intensity of MO2H+ at the plateau was 40 times higher than that of MH+ and 100 times higher than that of MOH+ in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO2H+ signal in the concentration range up to 60 μg/m3, which is high enough for hygiene management. In the low concentration range lower than 3 μg/m3, which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-μg/m3 vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  20. On the relationship between total ozone and atmospheric dynamics and chemistry at mid-latitudes – Part 1: Statistical models and spatial fingerprints of atmospheric dynamics and chemistry

    Directory of Open Access Journals (Sweden)

    L. Frossard

    2013-01-01

    Full Text Available We use statistical models for mean and extreme values of total column ozone to analyze "fingerprints" of atmospheric dynamics and chemistry on long-term ozone changes at northern and southern mid-latitudes on grid cell basis. At each grid cell, the r-largest order statistics method is used for the analysis of extreme events in low and high total ozone (termed ELOs and EHOs, respectively, and an autoregressive moving average (ARMA model is used for the corresponding mean value analysis. In order to describe the dynamical and chemical state of the atmosphere, the statistical models include important atmospheric covariates: the solar cycle, the Quasi-Biennial Oscillation (QBO, ozone depleting substances (ODS in terms of equivalent effective stratospheric chlorine (EESC, the North Atlantic Oscillation (NAO, the Antarctic Oscillation (AAO, the El Niño/Southern Oscillation (ENSO, and aerosol load after the volcanic eruptions of El Chichón and Mt. Pinatubo. The influence of the individual covariates on mean and extreme levels in total column ozone is derived on a grid cell basis. The results show that "fingerprints", i.e., significant influence, of dynamical and chemical features are captured in both the "bulk" and the tails of the statistical distribution of ozone, respectively described by mean values and EHOs/ELOs. While results for the solar cycle, QBO, and EESC are in good agreement with findings of earlier studies, unprecedented spatial fingerprints are retrieved for the dynamical covariates. Column ozone is enhanced over Labrador/Greenland, the North Atlantic sector and over the Norwegian Sea, but is reduced over Europe, Russia and the Eastern United States during the positive NAO phase, and vice-versa during the negative phase. The NAO's southern counterpart, the AAO, strongly influences column ozone at lower southern mid-latitudes, including the southern parts of South America and the Antarctic Peninsula, and the central southern mid

  1. Susceptibility of Diabetic Rats to Pulmonary and Systemic Effects of Inhaled Photochemically-Aged Atmosphere and Ozone (O3)

    Science.gov (United States)

    Susceptibility of Diabetic Rats to Pulmonary and Systemic Effects of Inhaled Photochemically-Aged Atmosphere and Ozone (O3)MC Schladweiler1, SJ Snow2, QT Krantz1, C King1, JD Krug2, N Modak2, A Henriquez3, V Bass4, DJ Miller3, JE Richards1, EH Boykin1, R Jaskot1, MI Gilmour1 and ...

  2. Arctic stratospheric ozone depletion and increased UVB radiation: potential impacts to human health.

    Science.gov (United States)

    De Fabo, Edward C

    2005-12-01

    Contrary to popular belief, stratospheric ozone depletion, and the resultant increase in solar UV-B (280-320 nm), are unlikely to fully recover soon. Notwithstanding the success of the Montreal Protocol in reducing the amount of ozone destroying chemicals into the stratosphere, the life-times of these compounds are such that even with full compliance with the Protocol by all countries, it will be decades before stratospheric ozone could return to pre-1980 levels. This raises the question, therefore, of what will happen to biological processes essential to the maintenance of life on earth which are sensitive to damage by increased UV-B radiation, particularly those involved with human health? The polar regions, because of the vagaries of climate and weather, are the bellwether for stratospheric ozone depletion and will, therefore, be the first to experience impacts due to increases in solar UV-B radiation. The impacts of these are incompletely understood and cannot be predicted with certainty. While some UV-B impacts on human health are recognized, much is unknown, unclear and uncertain. Thus, this paper attempts, as a first approximation, to point out potential impacts to the health and welfare of human inhabitants of the Arctic due to increased solar UV-B radiation associated with stratospheric ozone depletion. As will be seen, much more data is critically needed before adequate risk assessment can occur.

  3. Higher measured than modeled ozone production at increased NOx levels in the Colorado Front Range

    Science.gov (United States)

    Baier, Bianca C.; Brune, William H.; Miller, David O.; Blake, Donald; Long, Russell; Wisthaler, Armin; Cantrell, Christopher; Fried, Alan; Heikes, Brian; Brown, Steven; McDuffie, Erin; Flocke, Frank; Apel, Eric; Kaser, Lisa; Weinheimer, Andrew

    2017-09-01

    Chemical models must correctly calculate the ozone formation rate, P(O3), to accurately predict ozone levels and to test mitigation strategies. However, air quality models can have large uncertainties in P(O3) calculations, which can create uncertainties in ozone forecasts, especially during the summertime when P(O3) is high. One way to test mechanisms is to compare modeled P(O3) to direct measurements. During summer 2014, the Measurement of Ozone Production Sensor (MOPS) directly measured net P(O3) in Golden, CO, approximately 25 km west of Denver along the Colorado Front Range. Net P(O3) was compared to rates calculated by a photochemical box model that was constrained by measurements of other chemical species and that used a lumped chemical mechanism and a more explicit one. Median observed P(O3) was up to a factor of 2 higher than that modeled during early morning hours when nitric oxide (NO) levels were high and was similar to modeled P(O3) for the rest of the day. While all interferences and offsets in this new method are not fully understood, simulations of these possible uncertainties cannot explain the observed P(O3) behavior. Modeled and measured P(O3) and peroxy radical (HO2 and RO2) discrepancies observed here are similar to those presented in prior studies. While a missing atmospheric organic peroxy radical source from volatile organic compounds co-emitted with NO could be one plausible solution to the P(O3) discrepancy, such a source has not been identified and does not fully explain the peroxy radical model-data mismatch. If the MOPS accurately depicts atmospheric P(O3), then these results would imply that P(O3) in Golden, CO, would be NOx-sensitive for more of the day than what is calculated by models, extending the NOx-sensitive P(O3) regime from the afternoon further into the morning. These results could affect ozone reduction strategies for the region surrounding Golden and possibly other areas that do not comply with national ozone regulations

  4. Higher measured than modeled ozone production at increased NOx levels in the Colorado Front Range

    Directory of Open Access Journals (Sweden)

    B. C. Baier

    2017-09-01

    Full Text Available Chemical models must correctly calculate the ozone formation rate, P(O3, to accurately predict ozone levels and to test mitigation strategies. However, air quality models can have large uncertainties in P(O3 calculations, which can create uncertainties in ozone forecasts, especially during the summertime when P(O3 is high. One way to test mechanisms is to compare modeled P(O3 to direct measurements. During summer 2014, the Measurement of Ozone Production Sensor (MOPS directly measured net P(O3 in Golden, CO, approximately 25 km west of Denver along the Colorado Front Range. Net P(O3 was compared to rates calculated by a photochemical box model that was constrained by measurements of other chemical species and that used a lumped chemical mechanism and a more explicit one. Median observed P(O3 was up to a factor of 2 higher than that modeled during early morning hours when nitric oxide (NO levels were high and was similar to modeled P(O3 for the rest of the day. While all interferences and offsets in this new method are not fully understood, simulations of these possible uncertainties cannot explain the observed P(O3 behavior. Modeled and measured P(O3 and peroxy radical (HO2 and RO2 discrepancies observed here are similar to those presented in prior studies. While a missing atmospheric organic peroxy radical source from volatile organic compounds co-emitted with NO could be one plausible solution to the P(O3 discrepancy, such a source has not been identified and does not fully explain the peroxy radical model–data mismatch. If the MOPS accurately depicts atmospheric P(O3, then these results would imply that P(O3 in Golden, CO, would be NOx-sensitive for more of the day than what is calculated by models, extending the NOx-sensitive P(O3 regime from the afternoon further into the morning. These results could affect ozone reduction strategies for the region surrounding Golden and possibly other areas that do not comply with national ozone

  5. Volcanoes drive climate variability by emitting ozone weeks before eruptions, by forming lower stratospheric aerosols, by causing sustained ozone depletion, and by causing rapid changes in regional ozone concentrations affecting temperature and pressure differences driving atmospheric oscillations

    Science.gov (United States)

    Ward, P. L.

    2016-12-01

    Total column ozone observed by satellite on February 19, 2010, increased 75% in a plume from Eyjafjallajökull volcano in southern Iceland eastward past Novaya Zemlya, extending laterally from northern Greenland to southern Norway (http://youtu.be/wJFZcPEfoR4). Contemporaneous ground deformation and rapidly increasing numbers of earthquakes imply magma began rising from a sill 4-6 km below the volcano, erupting a month later. Whether the ozone formed from the magma or from very hot gases rising through cracks in the ground is unclear. On February 20-22, 1991, similar increases in ozone were observed north of Pinatubo volcano before its initial eruption on April 2 (http://youtu.be/5y1PU2Qu3ag). Annual average total column ozone during the year of most moderate to large explosive volcanic eruptions since routine observations of ozone began in 1927 has been substantially higher than normal. Increased total column ozone absorbs more solar ultraviolet-B radiation, warming the ozone layer and cooling Earth. Most major volcanic eruptions form sulfuric-acid aerosols in the lower part of the ozone layer providing aqueous surfaces on which heterogeneous chemical reactions enhance ozone depletion. Within a year, aerosol droplets grew large enough to reflect and scatter high-frequency solar radiation, cooling Earth 0.5oC for 2-3 years. Temperature anomalies in the northern hemisphere rose 0.7oC in 28 years from 1970 to 1998 (HadCRUT4), while annual average ozone at Arosa dropped 27 DU because of manufactured CFC gases. Beginning in August 2014, temperature anomalies in the northern hemisphere rose another 0.6oC in less than two years apparently because of the 6-month eruption of Bárðarbunga volcano in central Iceland, the highest rate of basaltic lava extrusion since 1783. Large extrusions of basaltic lava are typically contemporaneous with the greatest periods of warming throughout Earth history. Ozone concentrations at Arosa change by season typically from 370 DU during

  6. Vibrationally excited oxygen in the middle atmosphere. Evaluation of its potential as an additional source of ozone

    Energy Technology Data Exchange (ETDEWEB)

    Koppers, G.A.A.

    1996-11-01

    Ozone is `the` most important trace gas in the middle atmosphere. Despite the large efforts that have been made to calculate its concentration in the middle atmosphere there is long standing discrepancy between in-situ and remote sensing measurements on one hand and model results on the other. The latter tend to be about 30% too low in the upper stratosphere and mesosphere. One of the photolysis products of ozone itself, O2({upsilon}) - an oxygen molecule with extra vibrational energy, has been suggested as an intermediate in a reaction sequence that possibly could represent the missing ozone source. A key point in model calculations that estimate the magnitude of the proposed extra ozone source is the fractional population distribution of O2({upsilon}) after ozone photodissociation. Recent statistical calculations supply the vibrational distribution of O2({upsilon}) as a function of the wavelength at which ozone is dissociated. Based on these results a 2D chemical model that includes O2({upsilon}) chemistry has been used to investigate the importance of this mechanism. The extra ozone production by this mechanism has been compared for several other vibrational distributions taken from literature, different collisional deactivation rates of the excited oxygen fragments, and including a reaction between high vibrational excited oxygen with ground state oxygen producing two odd oxygen molecules. Our results indicate that regardless of whether the high vibrational reaction is included, alternatively the deactivation rates are decreased or not, the vibrational excited oxygen mechanism can not simultaneously match the absolute amount of the difference between the model results and SAGE II data and the height distribution of this difference. 23 refs, 17 figs, 2 tabs

  7. Trend and variability of atmospheric ozone over middle Indo-Gangetic Plain: impacts of seasonality and precursor gases.

    Science.gov (United States)

    Shukla, K; Srivastava, Prashant K; Banerjee, T; Aneja, Viney P

    2017-01-01

    Ozone dynamics in two urban background atmospheres over middle Indo-Gangetic Plain (IGP) were studied in two contexts: total columnar and ground-level ozone. In terms of total columnar ozone (TCO), emphases were made to compare satellite-based retrieval with ground-based observation and existing trend in decadal and seasonal variation was also identified. Both satellite-retrieved (Aura Ozone Monitoring Instrument-Differential Optical Absorption Spectroscopy (OMI-DOAS)) and ground-based observations (IMD-O3) revealed satisfying agreement with OMI-DOAS observation over predicting TCO with a positive bias of 7.24 % under all-sky conditions. Minor variation between daily daytime (r = 0.54; R 2 = 29 %; n = 275) and satellite overpass time-averaged TCO (r = 0.58; R 2 = 34 %; n = 208) was also recognized. A consistent and clear seasonal trend in columnar ozone (2005-2015) was noted with summertime (March-June) maxima (Varanasi, 290.9 ± 8.8; Lucknow, 295.6 ± 9.5 DU) and wintertime (December-February) minima (Varanasi, 257.4 ± 10.1; Lucknow, 258.8 ± 8.8 DU). Seasonal trend decomposition based on locally weighted regression smoothing technique identified marginally decreasing trend (Varanasi, 0.0084; Lucknow, 0.0096 DU year-1) especially due to reduction in monsoon time minima and summertime maxima. In continuation to TCO, variation in ground-level ozone in terms of seasonality and precursor gases were also analysed from September 2014 to August 2015. Both stations registered similar pattern of variation with Lucknow representing slightly higher annual mean (44.3 ± 30.6; range, 1.5-309.1 μg/m3) over Varanasi (38.5 ± 17.7; range, 4.9-104.2 μg/m3). Variation in ground-level ozone was further explained in terms water vapour, atmospheric boundary layer height and solar radiation. Ambient water vapour content was found to associate negatively (r = -0.28, n = 284) with ground-level ozone with considerable seasonal variation in Varanasi

  8. Atmospheric chemistry of short-chain haloolefins: photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs).

    Science.gov (United States)

    Wallington, T J; Sulbaek Andersen, M P; Nielsen, O J

    2015-06-01

    Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Does ozone increase ABA levels by non-enzymatic synthesis causing stomata to close?

    Science.gov (United States)

    McAdam, Erin L; Brodribb, Timothy J; McAdam, Scott A M

    2017-05-01

    Reactive oxygen species (ROS) are widely recognized as important regulators of stomatal aperture and plant gas exchange. The pathways through which stomata perceive ROS share many common linkages with the well characterized signalling pathway for the hormone abscisic acid (ABA), a major driver of stomatal closure. Given reports that ABA receptor mutants have no stomatal response to ozone-triggered ROS production, as well as evidence that all steps in the ABA biosynthetic pathway can be non-enzymatically converted by ROS, here we investigated the possibility that ozone closes stomata by directly converting ABA precursors to ABA. In plants where stomata were responsive to ozone, we found that foliar ABA levels rapidly increased upon exposure to ozone. Recovery of gas exchange post-exposure occurred only when ABA levels declined. Our data suggest that stomatal closure in response to ozone exposure occurs as a result of direct oxidation of ABA precursors leading to ABA production, but the importance of this ROS interaction remains uncertain under normal photosynthetic conditions. © 2017 John Wiley & Sons Ltd.

  10. Atmospheric oxidation chemistry and ozone production: Results from SHARP 2009 in Houston, Texas

    Science.gov (United States)

    Ren, Xinrong; van Duin, Diana; Cazorla, Maria; Chen, Shuang; Mao, Jingqiu; Zhang, Li; Brune, William H.; Flynn, James H.; Grossberg, Nicole; Lefer, Barry L.; Rappenglück, Bernhard; Wong, Kam W.; Tsai, Catalina; Stutz, Jochen; Dibb, Jack E.; Thomas Jobson, B.; Luke, Winston T.; Kelley, Paul

    2013-06-01

    Ozone (O3) and secondary fine particles come from the atmospheric oxidation chemistry that involves the hydroxyl radical (OH) and hydroperoxyl radical (HO2), which are together called HOx. Radical precursors such as nitrous acid (HONO) and formaldehyde (HCHO) significantly affect the HOx budget in urban environments. These chemical processes connect surface anthropogenic and natural emissions to local and regional air pollution. Using the data collected during the Study of Houston Atmospheric Radical Precursors (SHARP) in spring 2009, we examine atmospheric oxidation chemistry and O3 production in this polluted urban environment. A numerical box model with five different chemical mechanisms was used to simulate the oxidation processes and thus OH and HO2 in this study. In general, the model reproduced the measured OH and HO2 with all five chemical mechanisms producing similar levels of OH and HO2, although midday OH was overpredicted and nighttime OH and HO2 were underpredicted. The calculated HOx production was dominated by HONO photolysis in the early morning and by the photolysis of O3 and oxygenated volatile organic compounds (OVOCs) in the midday. On average, the daily HOx production rate was 24.6 ppbv d-1, of which 30% was from O3 photolysis, 22% from HONO photolysis, 15% from the photolysis of OVOCs (other than HCHO), 14% from HCHO photolysis, and 13% from O3 reactions with alkenes. The O3 production was sensitive to volatile organic compounds (VOCs) in the early morning but was sensitive to NOx for most of afternoon. This is similar to the behavior observed in two previous summertime studies in Houston: the Texas Air Quality Study in 2000 (TexAQS 2000) and the TexAQS II Radical and Aerosol Measurement Project in 2006 (TRAMP 2006). Ozone production in SHARP exhibits a longer NOx-sensitive period than TexAQS 2000 and TRAMP 2006, indicating that NOx control may be an efficient approach for the O3 control in springtime for Houston. Results from this study

  11. Evidence for an increase in the oxidative capacity of the atmosphere in the late twentieth century

    Science.gov (United States)

    Newland, Mike; Martinerie, Patricia; Witrant, Emmanuel; Helmig, Detlev; Worton, David; Hogan, Chris; Sturges, Bill; Reeves, Claire

    2016-04-01

    The hydroxyl radical, OH, is the dominant sink for the majority of trace gases in the troposphere. Thus, it plays a major role in controlling atmospheric chemical composition. However despite this importance there remains much uncertainty as to whether concentrations of OH have changed in the background atmosphere in recent decades. It has previously been reported that recent levels of OH in the troposphere (1997-2008) are well buffered against changes in atmospheric composition (Montzka et al., 2011). We present two independent records that suggest that there was a significant increase in concentrations of the OH radical in the northern hemisphere during the last two decades of the twentieth century. Measurements from Greenland firn air of the changing ratios of n-butane, iso-butane, n-pentane and iso-pentane were compared using a photochemical clock method. Using these changing ratios we calculate an increase in the chemical processing of the air (i.e. [OH].t) between 1980 and 2000. Assuming t to be constant this provides a semi-quantitative historic record of OH concentrations. Furthermore, measurements of three alkyl nitrates (also from Greenland firn air), secondary oxidation products of the alkanes, suggest an increase in the [NO]/[HO2] ratio in the background atmosphere. This could be indicative of increasing NOx concentrations during this period, which would be consistent with increasing [OH]. These two records are further corroborated by comparison with the long term trend in increasing ozone mixing ratios from background European sites. Knowledge of historic changes to the oxidative capacity of the atmosphere is fundamental to understanding the atmospheric records of trace gases and to determining historic trace gas emissions using top-down approaches. The results presented here have profound implications for our understanding of atmospheric composition in the past, the present and for predicting the future evolution of the atmosphere.

  12. The Antarctic Ozone Hole

    Science.gov (United States)

    Jones, Anna E.

    2008-01-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For…

  13. Atmosphere-Ocean Ozone Exchange – A Global Modeling Study of Biogeochemical, Atmospheric and Water-Side Turbulence Dependencies

    NARCIS (Netherlands)

    Ganzeveld, L.N.; Helmig, D.; Fairall, C.W.; Hare, J.; Pozzer, A.

    2009-01-01

    The significance of the removal of tropospheric ozone by the oceans, covering ~2/3 of the Earth's surface, has only been addressed in a few studies involving water tank, aircraft, and tower flux measurements. On the basis of results from these few observations of the ozone dry deposition velocity

  14. Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

    Science.gov (United States)

    Turnipseed, Andrew A.; Andersen, Peter C.; Williford, Craig J.; Ennis, Christine A.; Birks, John W.

    2017-06-01

    A new solid-phase scrubber for use in conventional ozone (O3) photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100-130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs) compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM) ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm), the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH), volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S.) Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

  15. Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection

    Science.gov (United States)

    Exposure to oxidant air pollution is associated with Increased respiratory morbiditses and susceptibility to Infections Ozone is a commonly encountered oxidant air pollutant, yet Its effects on influenza infections in humans are not known ‘the greater Mexico City area was the pri...

  16. Survival of Listeria monocytogenes on fresh blueberries (Vaccinium corymbosum) stored under controlled atmosphere and ozone.

    Science.gov (United States)

    Concha-Meyer, Anibal; Eifert, Joseph; Williams, Robert; Marcy, Joseph; Welbaum, Gregory

    2014-05-01

    Listeria monocytogenes is a foodborne pathogen that represents a high risk for consumers because it can grow under refrigeration conditions and can also develop acid tolerance. Fresh blueberries are hand-picked, packed, and transported under refrigeration without receiving a microbial inactivation treatment. The aim of this work was to study the survival of L. monocytogenes in fresh highbush blueberries stored at 4 or 12 °C under different controlled atmosphere conditions, including air (control); 5% O2, 15% CO2, 80% N2 (controlled atmosphere storage [CAS]); or ozone gas (O3), 4 ppm at 4 °C or 2.5 ppm at 12 °C, at high relative humidity (90 to 95%) for a total of 10 days. Fresh blueberries inside a plastic clamshell were spot inoculated with the bacteria and were stored at 4 or 12 °C in isolated cabinets under air, CAS, and O3 atmospheric conditions. Samples were evaluated on days 0, 1, 4, 7, and 10 for microbial growth using modified Oxford agar. CAS did not delay or inhibit L. monocytogenes growth in fresh blueberries after 10 days. O3 achieved 3- and 2-log reductions when compared with air treatment at 4 and 12 °C, respectively. Low concentrations of O3 together with proper refrigeration temperature can ensure product safety throughout transportation. O3 is a strong antimicrobial that safely decomposes to oxygen and water without leaving residues and can be used as an alternative method to prevent bacterial growth during a long transport period.

  17. The increased atmospheric greenhouse effect and regional climate change

    Energy Technology Data Exchange (ETDEWEB)

    Groenaas, S. [Bergen Univ. (Norway)

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. The main information for predicting future climate changes comes from integrating coupled climate models of the atmosphere, ocean and cryosphere. Regional climate change may be studied from the global integrations, however, resolution is coarse because of insufficient computer power. Attempts are being made to get more regional details out of the global integrations by ``downscaling`` the latter. This can be done in two ways. Firstly, limited area models with high resolution are applied, driven by the global results as boundary values. Secondly, statistical relationships have been found between observed meteorological parameters, like temperature and precipitation, and analyzed large scale gridded fields. The derived relations are then used on similar data from climate runs to give local interpretations. A review is given of literature on recent observations of climate variations and on predicted regional climate change. 18 refs., 4 figs.

  18. Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2012-12-01

    Full Text Available The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B, and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE, presented in a companion paper, and with the recent past (year 2000. Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario.

    As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000.

    Radiative forcing (RF calculations show that the net effect of AIR, SHIP and ROAD combined will change from a marginal cooling of −0.44 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 9.3 (B1 or −32 ± 18 mW m−2 (A1B in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −19 ± 5.3 mW m−2 in 2000 to

  19. Ozone increases susceptibility to antigen inhalation in allergic dogs

    Energy Technology Data Exchange (ETDEWEB)

    Yanai, M.; Ohrui, T.; Aikawa, T.; Okayama, H.; Sekizawa, K.; Maeyama, K.; Sasaki, H.; Takishima, T. (Tohoku Univ., Sendai (Japan))

    1990-06-01

    To determine whether O3 exposure increased airway responsiveness to antigen inhalation, we studied airway responsiveness to acetylcholine (ACh) and Ascaris suum antigen (AA) before and after O3 in dogs both sensitive and insensitive to AA. Airway responsiveness was assessed by determining the provocative concentration of ACh and AA aerosols that increased respiratory resistance (Rrs) to twice the base-line value. O3 (3 parts per million) increased airway responsiveness to ACh in dogs both sensitive and insensitive to AA, and it significantly decreased the ACh provocation concentration from 0.541 +/- 0.095 to 0.102 +/- 0.047 (SE) mg/ml (P less than 0.01; n = 10). AA aerosols, even at the highest concentration in combination with O3, did not increase Rrs in dogs insensitive to AA. However, O3 increased airway responsiveness to AA in AA-sensitive dogs and significantly decreased log AA provocation concentration from 2.34 +/- 0.22 to 0.50 +/- 0.17 (SE) log protein nitrogen units/ml (P less than 0.01; n = 7). O3-induced hyperresponsiveness to ACh returned to the base-line level within 2 wk, but hyperresponsiveness to AA continued for greater than 2 wk. The plasma histamine concentration after AA challenge was significantly higher after than before O3 (P less than 0.01). Intravenous infusion of OKY-046 (100 micrograms.kg-1.min-1), an inhibitor of thromboxane synthesis, inhibited the O3-induced increase in responsiveness to ACh, but it had no effects on the O3-induced increase in responsiveness to AA and the increase in the plasma histamine concentration. These results suggest that O3 increases susceptibility to the antigen in sensitized dogs via a different mechanism from that of O3-induced muscarinic hyperresponsiveness.

  20. Quasi-16-day period oscillations observed in middle atmospheric ozone and temperature in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Demissie, T.D.; Hibbins, R.E.; Espy, P.J. [Norwegian Univ. of Science and Technology (NTNU), Trondheim (Norway); Birkeland Centre for Space Science, Bergen (Norway); Kleinknecht, N.H.; Straub, C. [Norwegian Univ. of Science and Technology (NTNU), Trondheim (Norway)

    2013-09-01

    Nightly averaged mesospheric temperature derived from the hydroxyl nightglow at Rothera station (67 34' S, 68 08' W) and nightly midnight measurements of ozone mixing ratio obtained from Troll station (72 01' S, 2 32' E) in Antarctica have been used to investigate the presence and vertical profile of the quasi-16-day planetary wave in the stratosphere and mesosphere during the Antarctic winter of 2009. The variations caused by planetary waves on the ozone mixing ratio and temperature are discussed, and spectral and cross-correlation analyses are performed to extract the wave amplitudes and to examine the vertical structure of the wave from 34 to 80 km. The results show that while planetary-wave signatures with periods 3-12 days are strong below the stratopause, the oscillations associated with the 16-day wave are the strongest and present in both the mesosphere and stratosphere. The period of the wave is found to increase below 42 km due to the Doppler shifting by the strong eastward zonal wind. The 16-day oscillation in the temperature is found to be correlated and phase coherent with the corresponding oscillation observed in O{sub 3} volume mixing ratio at all levels, and the wave is found to have vertical phase fronts consistent with a normal mode structure. (orig.)

  1. Quasi-16-day period oscillations observed in middle atmospheric ozone and temperature in Antarctica

    Directory of Open Access Journals (Sweden)

    T. D. Demissie

    2013-07-01

    Full Text Available Nightly averaged mesospheric temperature derived from the hydroxyl nightglow at Rothera station (67°34' S, 68°08' W and nightly midnight measurements of ozone mixing ratio obtained from Troll station (72°01' S, 2°32' E in Antarctica have been used to investigate the presence and vertical profile of the quasi-16-day planetary wave in the stratosphere and mesosphere during the Antarctic winter of 2009. The variations caused by planetary waves on the ozone mixing ratio and temperature are discussed, and spectral and cross-correlation analyses are performed to extract the wave amplitudes and to examine the vertical structure of the wave from 34 to 80 km. The results show that while planetary-wave signatures with periods 3–12 days are strong below the stratopause, the oscillations associated with the 16-day wave are the strongest and present in both the mesosphere and stratosphere. The period of the wave is found to increase below 42 km due to the Doppler shifting by the strong eastward zonal wind. The 16-day oscillation in the temperature is found to be correlated and phase coherent with the corresponding oscillation observed in O3 volume mixing ratio at all levels, and the wave is found to have vertical phase fronts consistent with a normal mode structure.

  2. Wind increase over cooling Southern Ocean driven by tropical warming and polar ozone hole

    Science.gov (United States)

    Schneider, D. P.; Fan, T.; Deser, C.

    2014-12-01

    Changing winds over the Southern Ocean have had dramatic impacts on Antarctic sea ice extent, anthropogenic heat and carbon uptake by the ocean, and the contribution of the Antarctic ice sheet to global sea level rise. An overall intensification of the surface westerly winds has been attributed to several different forcings, including stratospheric ozone depletion, greenhouse gasses, and tropical sea surface temperatures (SSTs). However, the relative roles of these drivers have not been well quantified. Reconciling previous explanations, here we show that a combination of tropical SSTs and stratospheric ozone loss largely explains the magnitude, regional patterns, and seasonality of observed lower tropospheric zonal wind trends over the Southern Ocean. We evaluate multiple ensembles of atmospheric model simulations, with each ensemble forced by one or a combination of drivers. Considering all months of the year, tropical SSTs are the largest contributor to observed zonal wind trends over 40°S-80°S. In austral summer, tropical SSTs and stratospheric ozone loss have contributed approximately equally to near-surface wind trends. The tropical contribution in austral summer is associated with tropics-wide warming, which has been moderated in recent decades by a prevalence of La-Niña events. The relative phasing of natural variability with anthropogenic forcing is therefore essential for understanding and predicting Southern Ocean climate change.

  3. Combined atmospheric oxidant capacity and increased levels of exhaled nitric oxide

    Science.gov (United States)

    Yang, Changyuan; Li, Huichu; Chen, Renjie; Xu, Wenxi; Wang, Cuicui; Tse, Lap Ah; Zhao, Zhuohui; Kan, Haidong

    2016-07-01

    Nitrogen dioxide and ozone are two interrelated oxidative pollutants in the atmosphere. Few studies have evaluated the health effects of combined oxidant capacity (O x ). We investigated the short-term effects of O x on fractional exhaled nitric oxide (FeNO), a well-established biomarker for airway inflammation, in a group of chronic obstructive pulmonary disease patients. Real-time concentrations of O x were obtained by calculating directly the sum of nitrogen dioxide and ozone. Linear mixed-effect models were applied to explore the acute effects of O x on FeNO levels. Short-term exposure to Ox was significantly associated with elevated FeNO. This effect was strongest in the first 24 h after exposure, and was robust to the adjustment of PM2.5. A 10 μg m-3 increase in 24 h average concentrations of O x was associated with 4.28% (95% confidence interval: 1.19%, 7.37%) increase in FeNO. The effect estimates were statistically significant only among males, elders, and those with body mass index ≥24 kg m-2, a comorbidity, higher educational attainment, or moderate airflow limitation. This analysis demonstrated an independent effect of O x on respiratory inflammation, and suggested that a single metric O x might serve as a preferable indicator of atmospheric oxidative capacity in further air pollution epidemiological studies.

  4. Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

    Science.gov (United States)

    Jud, W.; Fischer, L.; Canaval, E.; Wohlfahrt, G.; Tissier, A.; Hansel, A.

    2016-01-01

    Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. Plant injuries have been linked to the uptake of ozone through stomatal pores and oxidative damage of the internal leaf tissue. But a striking question remains: can surface reactions limit the stomatal uptake of ozone and therefore reduce its detrimental effects to plants?In this laboratory study we could show that semi-volatile organic compounds exuded by the glandular trichomes of different Nicotiana tabacum varieties are an efficient ozone sink at the plant surface. In our experiments, different diterpenoid compounds were responsible for a strongly variety-dependent ozone uptake of plants under dark conditions, when stomatal pores are almost closed. Surface reactions of ozone were accompanied by a prompt release of oxygenated volatile organic compounds, which could be linked to the corresponding precursor compounds: ozonolysis cis-abienol (C20H34O) - a diterpenoid with two exocyclic double bonds - caused emissions of formaldehyde (HCHO) and methyl vinyl ketone (C4H6O). The ring-structured cembratrien-diols (C20H34O2) with three endocyclic double bonds need at least two ozonolysis steps to form volatile carbonyls such as 4-oxopentanal (C5H8O2), which we could observe in the gas phase, too.Fluid dynamic calculations were used to model ozone distribution in the diffusion-limited leaf boundary layer under daylight conditions. In the case of an ozone-reactive leaf surface, ozone gradients in the vicinity of stomatal pores are changed in such a way that the ozone flux through the open stomata is strongly reduced.Our results show that unsaturated semi-volatile compounds at the plant surface should be considered as a source of oxygenated volatile organic compounds, impacting gas phase chemistry, as well as efficient ozone sink improving the ozone tolerance of plants.

  5. Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    W. Jud

    2016-01-01

    Full Text Available Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. Plant injuries have been linked to the uptake of ozone through stomatal pores and oxidative damage of the internal leaf tissue. But a striking question remains: can surface reactions limit the stomatal uptake of ozone and therefore reduce its detrimental effects to plants?In this laboratory study we could show that semi-volatile organic compounds exuded by the glandular trichomes of different Nicotiana tabacum varieties are an efficient ozone sink at the plant surface. In our experiments, different diterpenoid compounds were responsible for a strongly variety-dependent ozone uptake of plants under dark conditions, when stomatal pores are almost closed. Surface reactions of ozone were accompanied by a prompt release of oxygenated volatile organic compounds, which could be linked to the corresponding precursor compounds: ozonolysis cis-abienol (C20H34O – a diterpenoid with two exocyclic double bonds – caused emissions of formaldehyde (HCHO and methyl vinyl ketone (C4H6O. The ring-structured cembratrien-diols (C20H34O2 with three endocyclic double bonds need at least two ozonolysis steps to form volatile carbonyls such as 4-oxopentanal (C5H8O2, which we could observe in the gas phase, too.Fluid dynamic calculations were used to model ozone distribution in the diffusion-limited leaf boundary layer under daylight conditions. In the case of an ozone-reactive leaf surface, ozone gradients in the vicinity of stomatal pores are changed in such a way that the ozone flux through the open stomata is strongly reduced.Our results show that unsaturated semi-volatile compounds at the plant surface should be considered as a source of oxygenated volatile organic compounds, impacting gas phase chemistry, as well as efficient ozone sink improving the ozone tolerance of plants.

  6. Acute ozone exposure increases plasma prostaglandin F2 alpha in ozone-sensitive human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Schelegle, E.S.; Adams, W.C.; Giri, S.N.; Siefkin, A.D.

    1989-07-01

    Twenty O/sub 3/-sensitive and /sup 2/O O/sub 3/-nonsensitive subjects participated in a study to investigate the effects of disparate O/sub 3/ sensitivity on plasma prostaglandin F2 alpha responses consequent to exposure to ambient O3 concentrations. Subjects were selected from a pool of 75 normal healthy college-aged males who had been previously exposed to 0.35 ppm O3 for 1 h at an exercising VE of 60 L/min. The selection criterion used was the observed decrement in FEV1 after the O/sub 3/ exposure: O/sub 3/-sensitive, FEV1 decrement greater than 24%; O/sub 3/-nonsensitive, FEV1 decrement less than 11%. Each subject was exposed to filtered air and to 0.20 and 0.35 ppm O/sub 3/ for 80 min while exercising at a VE of 50 L/min. These experimental protocols were divided into two 40-min sessions separated by a period of 4 to 10 min. PGF2 alpha, FVC, FEV1, and FEF25-75 were evaluated before, during, and after each protocol. SGaw and Vtg were measured before and after each protocol. Plasma PGF2 alpha was significantly increased in the O/sub 3/-sensitive group during and after the 0.35-ppm O/sub 3/ exposure.

  7. Link Winds: A visual data analysis system and its application to the atmospheric ozone depletion problem

    Science.gov (United States)

    Jacobson, Allan S.; Berkin, Andrew L.

    1995-01-01

    The Linked Windows Interactive Data System (LinkWinds) is a prototype visual data exploration system resulting from a NASA Jet Propulsion Laboratory (JPL) program of research into the application of graphical methods for rapidly accessing, displaying, and analyzing large multi variate multidisciplinary data sets. Running under UNIX it is an integrated multi-application executing environment using a data-linking paradigm to dynamically interconnect and control multiple windows containing a variety of displays and manipulators. This paradigm, resulting in a system similar to a graphical spreadsheet, is not only a powerful method for organizing large amounts of data for analysis, but leads to a highly intuitive, easy-to-learn user interface. It provides great flexibility in rapidly interacting with large masses of complex data to detect trends, correlations, and anomalies. The system, containing an expanding suite of non-domain-specific applications, provides for the ingestion of a variety of data base formats and hard -copy output of all displays. Remote networked workstations running LinkWinds may be interconnected, providing a multiuser science environment (MUSE) for collaborative data exploration by a distributed science team. The system is being developed in close collaboration with investigators in a variety of science disciplines using both archived and real-time data. It is currently being used to support the Microwave Limb Sounder (MLS) in orbit aboard the Upper Atmosphere Research Satellite (UARS). This paper describes the application of LinkWinds to this data to rapidly detect features, such as the ozone hole configuration, and to analyze correlations between chemical constituents of the atmosphere.

  8. Modeling coupled interactions of carbon, water, and ozone exchange between terrestrial ecosystems and the atmosphere. I: model description.

    Science.gov (United States)

    Nikolov, Ned; Zeller, Karl F

    2003-01-01

    A new biophysical model (FORFLUX) is presented to study the simultaneous exchange of ozone, carbon dioxide, and water vapor between terrestrial ecosystems and the atmosphere. The model mechanistically couples all major processes controlling ecosystem flows trace gases and water implementing recent concepts in plant eco-physiology, micrometeorology, and soil hydrology. FORFLUX consists of four interconnected modules-a leaf photosynthesis model, a canopy flux model, a soil heat-, water- and CO2- transport model, and a snow pack model. Photosynthesis, water-vapor flux and ozone uptake at the leaf level are computed by the LEAFC3 sub-model. The canopy module scales leaf responses to a stand level by numerical integration of the LEAFC3model over canopy leaf area index (LAI). The integration takes into account (1) radiative transfer inside the canopy, (2) variation of foliage photosynthetic capacity with canopy depth, (3) wind speed attenuation throughout the canopy, and (4) rainfall interception by foliage elements. The soil module uses principles of the diffusion theory to predict temperature and moisture dynamics within the soil column, evaporation, and CO2 efflux from soil. The effect of soil heterogeneity on field-scale fluxes is simulated employing the Bresler-Dagan stochastic concept. The accumulation and melt of snow on the ground is predicted using an explicit energy balance approach. Ozone deposition is modeled as a sum of three fluxes- ozone uptake via plant stomata, deposition to non-transpiring plant surfaces, and ozone flux into the ground. All biophysical interactions are computed hourly while model projections are made at either hourly or daily time step. FORFLUX represents a comprehensive approach to studying ozone deposition and its link to carbon and water cycles in terrestrial ecosystems.

  9. Efficacy of endodontic applications of ozone and low-temperature atmospheric pressure plasma on root canals infected with Enterococcus faecalis.

    Science.gov (United States)

    Üreyen Kaya, B; Kececi, A D; Güldaş, H E; Çetin, E S; Öztürk, T; Öksuz, L; Bozduman, F

    2014-01-01

    This study aimed to compare the antimicrobial efficacy of low-temperature atmospheric pressure plasma (LTAPP) design and gaseous ozone delivery system with 2.5% NaOCl on Enterococcus faecalis in root canal walls and dentine tubules. The samples were divided into LTAPP (n = 12), ozone (n = 12), NaOCl (positive control, n = 12) and saline (negative control, n = 6) groups. Microbial samples were collected using paper points and dentin chips from root canals. Antimicrobial efficacy was assessed by counting the colony-forming units of Ent. faecalis before and after each irrigation protocol. Data were analysed using Kruskal-Wallis, Wilcoxon signed-rank, Friedman and Bonferroni t (Dunn's test)-tests (P = 0.05). The microbial sampling with paper points showed antibacterial efficacy of NaOCl, LTAPP, ozone and saline in descending order, respectively (P 0.05). NaOCl and LTAPP were better than ozone at the coronal and middle parts of the root canals (P endodontic treatment. The present study handles different perspectives on chemomechanical preparation of root canals. Ozone and low-temperature atmospheric pressure plasma (LTAPP) were investigated to determine whether they could be an alternative for NaOCl. Up to now, chemical solutions (NaOCl, chlorhexidine digluconate, etc...) have been used to disinfect the root canals. When the reported effects of LTAPP on biological and chemical decontamination were taken into consideration, a question rose whether it has antimicrobial efficacy in root canals infected with E. faecalis. According to the findings of the present study, LTAPP may constitute a promising aid in endodontics in disinfection of root canals. © 2013 The Society for Applied Microbiology.

  10. Characterization of atmospheric oxidants during, and after 2014 APEC summit: a case study of peroxides and ozone

    Science.gov (United States)

    Shen, H.; Chen, Z.; Huang, L.

    2016-12-01

    Peroxides and ozone (O3) are important atmospheric oxidants, and are directly related to the cycling of radicals in the atmosphere. They have a profound impact on many critical atmospheric chemical processes, and are closely associated with regional air pollution and global climate change. Many filed measurements have been conducted to study their concentrations, budget, and roles in the atmospheric chemistry in the past few decades. However, the characteristic and influencing factors of concentrations of peroxides and O3 are still not fully understood, especially in the polluted area. In this study, measurements for atmospheric peroxides and O3 were conducted simultaneously at PKU site in Beijing, China during, and after the 2014 Asia-Pacific Economic Cooperation (APEC) summit when strict pollution control measures were deployed. Hydrogen peroxide (H2O2) was the predominant peroxide observed, and occasionally, hydroxylmethyl hydroperoxide (HMHP) was detected. The average concentrations of H2O2 and O3 were 22.6±23.7pptv and 14.8±13.4ppbv, respectively. Both H2O2 and O3 showed distinct diurnal variations, with a peak between 14:00-16:00 for O3, and 18:00-20:00 for H2O2. However, the emergence of the H2O2 peak shifted to the night further both during, and after APEC compared to summer observations at the same site and in clean areas, but the exact mechanism is not clear. Concentrations of H2O2 and O3 were higher during APEC with A (After APEC)/D (During APEC) ratios of 0.3 and 0.7, respectively, contrary to the changes of most of the other observed trace constituents. We discussed the influencing factors in detail, and confirmed that the reduction of NOx was the decisive factors. Additionally, we found a sudden increase of concentrations of H2O2 and O3 on the early morning of 11 November. By analyzing the changes of related meteorological parameters, backward air mass trajectories, and pressure vertical velocity, we ascribed this to the downward transport of air

  11. Evidence of a long-term increase in tropospheric ozone from Pic du Midi data series: Consequences: Positive radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Marenco, A.; Gouget, H.; Nedelec, P.; Pages, J.; Karcher, F. [Univ. Paul Sabatier, Toulouse (France)]|[Centre National de Recerches Meteorologiques, Toulouse (France)

    1994-08-01

    The rate at which ozone is increasing in the troposphere is uncertain due to the lack of accurate long-term measurements. Old ozone measurements obtained at the Pic du Midi Observatory (3000 m high, southwestern France) were recently rediscovered. Four sets of data available at this station are presented. The results show an increase in ozone by a factor of 5 since the beginning of the twentieth century, corresponding to an exponential increase of 1.6% per year, although this trend is probably higher (2.4% per year) for the last few decades. A stable 10 ppb ozone mixing ratio is observed during the first 20 years of the series, which is representative to the preindustrial era ozone level. The increase is seen to start around 1895. Other data, obtained at various European high-altitude stations between 1920 and 1980, tie in closely with the Pic du Midi observations. A tentative evaluation of the impact of tropospheric ozone on radiative forcing confirms that ozone is currently the second most significant greenhouse gas, responsible for 22% and 13% of radiative forcing changes since 1800 in the northern and southern hemispheres, respectively. If these rates were to be maintained in the future, ozone would continue to evolve differently in the two hemispheres (maximum level in the northern hemisphere) and could make an even more significant contribution to the radiative forcing of the northern hemisphere.

  12. Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain

    Science.gov (United States)

    Saiz-Lopez, A.; Borge, R.; Notario, A.; Adame, J. A.; Paz, D. De La; Querol, X.; Artíñano, B.; Gómez-Moreno, F. J.; Cuevas, C. A.

    2017-04-01

    Atmospheric oxidants such as ozone (O3), hydroxyl and nitrate radicals (OH and NO3) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30-40% in ambient air O3 levels, along with a decrease of 20-40% in NO2, from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO3, respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO3, respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NOx emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities.

  13. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Science.gov (United States)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

  14. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S; Gesche, R [Ferdinand-Braun-Institut (FBH), Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Bibinov, N; Awakowicz, P [Institute for Electrical Engineering and Plasma Technology, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany)], E-mail: Silvio.Kuehn@fbh-berlin.de, E-mail: Nikita.Bibinov@rub.de

    2010-01-15

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O{sub 3}, correspondingly, are generated.

  15. OZONE CONCENTRATION ATTRIBUTABLE PREMATURE DEATH IN POLAND

    Directory of Open Access Journals (Sweden)

    Krzysztof Skotak

    2010-03-01

    Full Text Available Ozone in the lower part of the atmosphere (troposphere, strong photochemical oxidant, is not directly emitted to the atmosphere but formed through a series of complex reactions. Ozone concentrations depends on ozone precursors air contamination (mainly nitrogen dioxide and non-methane volatile organic compounds and meteorological conditions (temperature and solar radiation. The main sectors emitted ozone precursors are road transport, power and heat generation plants, household (heating, industry, and petrol storage and distribution. Ozone and some of its precursors are also transported long distances in the atmosphere and are therefore considered a transboundary problem. As a result, the ozone concentrations are often low in busy urban areas and higher in suburban and rural areas. Nowadays, instead of particulate matter, ozone is one of the most widespread global air pollution problems. In and around urban areas, relatively large gradients of ozone can be observed. Because of its high reactivity in elevated concentrations ozone causes serious health problems and damage to ecosystems, agricultural crops and materials. Main ill-health endpoints as a results of ozone concentrations can be characterised as an effect of pulmonary and cardiovascular system, time morbidity and mortality series, development of atherosclerosis and asthma and finally reduction in life expectancy. The associations with increased daily mortality due to ozone concentrations are confirmed by many researches and epidemiological studies. Estimation of the level selected ill-health endpoints (mortality in total and due to cardiovascular and respiratory causes as a result of the short-term ozone exposure in Poland was the main aim of the project. Final results have been done based on estimation method elaborated by WHO, ozone measurements from National Air Quality Monitoring System and statistical information such as mortality rate and populations. All analysis have been done in

  16. Increasing global agricultural production by reducing ozone damages via methane emission controls and ozone-resistant cultivar selection.

    Science.gov (United States)

    Avnery, Shiri; Mauzerall, Denise L; Fiore, Arlene M

    2013-04-01

    Meeting the projected 50% increase in global grain demand by 2030 without further environmental degradation poses a major challenge for agricultural production. Because surface ozone (O3 ) has a significant negative impact on crop yields, one way to increase future production is to reduce O3 -induced agricultural losses. We present two strategies whereby O3 damage to crops may be reduced. We first examine the potential benefits of an O3 mitigation strategy motivated by climate change goals: gradual emission reductions of methane (CH4 ), an important greenhouse gas and tropospheric O3 precursor that has not yet been targeted for O3 pollution abatement. Our second strategy focuses on adapting crops to O3 exposure by selecting cultivars with demonstrated O3 resistance. We find that the CH4 reductions considered would increase global production of soybean, maize, and wheat by 23-102 Mt in 2030 - the equivalent of a ~2-8% increase in year 2000 production worth $3.5-15 billion worldwide (USD2000 ), increasing the cost effectiveness of this CH4 mitigation policy. Choosing crop varieties with O3 resistance (relative to median-sensitivity cultivars) could improve global agricultural production in 2030 by over 140 Mt, the equivalent of a 12% increase in 2000 production worth ~$22 billion. Benefits are dominated by improvements for wheat in South Asia, where O3 -induced crop losses would otherwise be severe. Combining the two strategies generates benefits that are less than fully additive, given the nature of O3 effects on crops. Our results demonstrate the significant potential to sustainably improve global agricultural production by decreasing O3 -induced reductions in crop yields. © 2012 Blackwell Publishing Ltd.

  17. Atmospheric lifetimes and Ozone Depletion Potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    Science.gov (United States)

    Patten, K. O.; Wuebbles, D. J.

    2010-11-01

    The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP) and trans-1,2-dichloroethylene (tDCE) have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs) for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. 53% of the ozone loss due to tCFP and 98% of the ozone loss due to tDCE take place in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to affect ozone at quantities likely to be emitted to the atmosphere.

  18. Atmospheric lifetimes and Ozone Depletion Potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    Directory of Open Access Journals (Sweden)

    K. O. Patten

    2010-11-01

    Full Text Available The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP and trans-1,2-dichloroethylene (tDCE have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. 53% of the ozone loss due to tCFP and 98% of the ozone loss due to tDCE take place in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to affect ozone at quantities likely to be emitted to the atmosphere.

  19. The Feasibility of Tropospheric and Total Ozone Determination Using a Fabry-perot Interferometer as a Satellite-based Nadir-viewing Atmospheric Sensor. Ph.D. Thesis

    Science.gov (United States)

    Larar, Allen Maurice

    1993-01-01

    Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis

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

    Science.gov (United States)

    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.

  1. Fate of Chloromethanes in the Atmospheric Environment: Implications for Human Health, Ozone Formation and Depletion, and Global Warming Impacts.

    Science.gov (United States)

    Tsai, Wen-Tien

    2017-09-21

    Among the halogenated hydrocarbons, chloromethanes (i.e., methyl chloride, CH₃Cl; methylene chloride, CH₂Cl₂; chloroform, CHCl₃; and carbon tetrachloride, CCl₄) play a vital role due to their extensive uses as solvents and chemical intermediates. This article aims to review their main chemical/physical properties and commercial/industrial uses, as well as the environment and health hazards posed by them and their toxic decomposition products. The environmental properties (including atmospheric lifetime, radiative efficiency, ozone depletion potential, global warming potential, photochemical ozone creation potential, and surface mixing ratio) of these chlorinated methanes are also reviewed. In addition, this paper further discusses their atmospheric fates and human health implications because they are apt to reside in the lower atmosphere when released into the environment. According to the atmospheric degradation mechanism, their toxic degradation products in the troposphere include hydrogen chloride (HCl), carbon monoxide (CO), chlorine (Cl₂), formyl chloride (HCOCl), carbonyl chloride (COCl₂), and hydrogen peroxide (H₂O₂). Among them, COCl₂ (also called phosgene) is a powerful irritating gas, which is easily hydrolyzed or thermally decomposed to form hydrogen chloride.

  2. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  3. Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

    Directory of Open Access Journals (Sweden)

    A. A. Turnipseed

    2017-06-01

    Full Text Available A new solid-phase scrubber for use in conventional ozone (O3 photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100–130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm, the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH, volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S. Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

  4. Compact, Rugged and Low-Cost Atmospheric Ozone DIAL Transmitter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bridger Photonics Inc. (Bridger) proposes to develop the most compact, efficient and low-cost ultra-violet ozone differential absorption lidar (DIAL) transmitter...

  5. Retrieval and molecule sensitivity studies for the global ozone monitoring experiment and the scanning imaging absorption spectrometer for atmospheric chartography

    Science.gov (United States)

    Chance, Kelly V.; Burrows, John P.; Schneider, Wolfgang

    1991-01-01

    The Global Ozone Monitoring Experiment (GOME) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) are diode based spectrometers that will make atmospheric constituent and aerosol measurements from European satellite platforms beginning in the mid 1990's. GOME measures the atmosphere in the UV and visible in nadir scanning, while SCIAMACHY performs a combination of nadir, limb, and occultation measurements in the UV, visible, and infrared. A summary is presented of the sensitivity studies that were performed for SCIAMACHY measurements. As the GOME measurement capability is a subset of the SCIAMACHY measurement capability, the nadir, UV, and visible portion of the studies is shown to apply to GOME as well.

  6. Positive feedback between increasing atmospheric CO2 and ecosystem productivity

    Science.gov (United States)

    Gelfand, I.; Hamilton, S. K.; Robertson, G. P.

    2009-12-01

    Increasing atmospheric CO2 will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO2 will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration. The plant physiological response that drives these effects is believed to be an increase in carbon uptake either by (a) stronger CO2 gradient between the stomata and the atmosphere, or by (b) reduced CO2 limitation of enzymatic carboxylation within the leaf. The (a) scenario will lead to increased water use efficiency (WUE) in plants. However, evidence for increased WUE is mostly based on modeling studies, and experiments producing a short duration or step-wise increase in CO2 concentration (e.g. free-air CO2 enrichment). We hypothesize that the increase in atmospheric CO2 concentration is having a positive effect on ecosystem productivity and WUE. To investigate this hypothesis, we analyzed meteorological, ANPP, and soil CO2 flux datasets together with carbon isotopic ratio (13C/12C) of archived plant samples from the long term ecological research (LTER) program at Kellogg Biological Station. The datasets were collected between 1989 and 2007 (corresponding to an increase in atmospheric CO2 concentration of ~33 ppmv at Mauna Loa). Wheat (Triticum aestivum) samples taken from 1989 and 2007 show a significant decrease in the C isotope discrimination factor (Δ) over time. Stomatal conductance is directly related to Δ, and thus Δ is inversely related to plant intrinsic WUE (iWUE). Historical changes in the 13C/12C ratio (δ13C) in samples of a perennial forb, Canada goldenrod (Solidago canadensis), taken from adjacent successional fields, indicate changes in Δ upon uptake of CO2 as well. These temporal trends in Δ suggest a positive feedback between the increasing CO2 concentration in the

  7. Overt and Latent Cardiac Effects of Ozone Inhalation in Rats: Evidence for Autonomic Modulation and Increased Myocardial Vulnerability

    Science.gov (United States)

    Background: Ozone (03) is a well-documented respiratory oxidant, but increasing epidemiologic evidence points to extra-pulmonary effects including positive associations between ambient 03 concentrations and cardiovascular morbidity/mortality. Objectives: With preliminary reports ...

  8. The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

    Directory of Open Access Journals (Sweden)

    P. Jöckel

    2006-01-01

    Full Text Available The new Modular Earth Submodel System (MESSy describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model setup up to 0.01 hPa was used at spectral T42 resolution to simulate the lower and middle atmosphere. With the high vertical resolution the model simulates the Quasi-Biennial Oscillation. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. In the simulations presented here a Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. This allows an efficient and direct evaluation with satellite and in-situ data. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated well, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of inter-annual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy

  9. Evaluation of the impact of atmospheric ozone and aerosols on the horizontal global/diffuse UV Index at Livorno (Italy)

    Science.gov (United States)

    Scaglione, Daniele; Giulietti, Danilo; Morelli, Marco

    2016-08-01

    A study was conducted at Livorno (Italy) to evaluate the impact of atmospheric aerosols and ozone on the solar UV radiation and its diffuse component at ground in clear sky conditions. Solar UV radiation has been quantified in terms of UV Index (UVI), following the ISO 17166:1999/CIE S007/E-1998 international standard. UVI has been calculated by exploiting the libRadtran radiative transfer modelling software as a function of both the Aerosols Optical Depth (AOD) and the Total Ozone Column (TOC). In particular AOD and TOC values have been remotely sensed by the Ozone Monitoring Instrument (OMI) on board the NASA's EOS (Earth Observing System) satellites constellation. An experimental confirmation was also obtained by exploiting global UVI ground-based measurements from the 26/9/14 to 12/8/15 and diffuse UVI ground-based measurements from the 17/5/15 to 12/8/15. For every considered value of Solar Zenith Angle (SZA) and atmospheric condition, estimates and measurements confirm that the diffuse component contributes for more than 50% on the global UV radiation. Therefore an exposure of human skin also to diffuse solar UV radiation can be potentially harmful for health and need to be accurately monitored, e.g. by exploiting innovative applications such as a mobile app with a satellite-based UV dosimeter that has been developed. Global and diffuse UVI variations due to the atmosphere are primarily caused by the TOC variations (typically cyclic): the maximum TOC variation detected by OMI in the area under study leads to a corresponding variation in global and diffuse UVI of about 50%. Aerosols in the area concerned, mainly of maritime nature, have instead weaker effects causing a maximum variation of the global and diffuse UVI respectively of 9% and 35% with an SZA of 20° and respectively of 13% and 10% with an SZA of 60°.

  10. Increase in sunburns and photosensitivity disorders at the edge of the Antarctic ozone hole, southern Chile, 1986-2000.

    Science.gov (United States)

    Abarca, Jaime F; Casiccia, Claudio C; Zamorano, Felix D

    2002-02-01

    Over the past 15 years Punta Arenas, Chile, a medium-sized city located on the extreme southern tip of South America, has repeatedly been exposed to acute, sudden episodes of highly increased levels of ultraviolet B (UVB) 280-320 nm radiation because of the passage of the spring Antarctic "Ozone Hole" overhead, or nearby. Our purpose was to observe the relationship between episodes of ozone depletion, increased UVB radiation, and sunburns and photosensitivity disorders in Punta Arenas, Chile, during spring. Incidence of photosensitivity disorders and sunburns was registered by dermatologists during each of the past 15 springs. Local data of sudden, severe ozone depletions (ozone hole is a matter of special concern.

  11. The effect of entrainment through atmospheric boundary layer growth on observed and modeled surface ozone in the Colorado Front Range

    Science.gov (United States)

    Kaser, L.; Patton, E. G.; Pfister, G. G.; Weinheimer, A. J.; Montzka, D. D.; Flocke, F.; Thompson, A. M.; Stauffer, R. M.; Halliday, H. S.

    2017-06-01

    Ozone concentrations at the Earth's surface are controlled by meteorological and chemical processes and are a function of advection, entrainment, deposition, and net chemical production/loss. The relative contributions of these processes vary in time and space. Understanding the relative importance of these processes controlling surface ozone concentrations is an essential component for designing effective regulatory strategies. Here we focus on the diurnal cycle of entrainment through atmospheric boundary layer (ABL) growth in the Colorado Front Range. Aircraft soundings and surface observations collected in July/August 2014 during the DISCOVER-AQ/FRAPPÉ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality/Front Range Air Pollution and Photochemistry Éxperiment) campaigns and equivalent data simulated by a regional chemical transport model are analyzed. Entrainment through ABL growth is most important in the early morning, fumigating the surface at a rate of 5 ppbv/h. The fumigation effect weakens near noon and changes sign to become a small dilution effect in the afternoon on the order of -1 ppbv/h. The chemical transport model WRF-Chem (Weather Research and Forecasting Model with chemistry) underestimates ozone at all altitudes during this study on the order of 10-15 ppbv. The entrainment through ABL growth is overestimated by the model in the order of 0.6-0.8 ppbv/h. This results from differences in boundary layer growth in the morning and ozone concentration jump across the ABL top in the afternoon. This implicates stronger modeled fumigation in the morning and weaker modeled dilution after 11:00 LT.

  12. Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

    Directory of Open Access Journals (Sweden)

    A. Gabriel

    2011-09-01

    Full Text Available Stationary wave patterns in middle atmospheric ozone (O3 and water vapour (H2O are an important factor in the atmospheric circulation, but there is a strong gap in diagnosing and understanding their configuration and origin. Based on Odin satellite data from 2001 to 2010 we investigate the stationary wave patterns in O3 and H2O as indicated by the seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means. At mid- and polar latitudes we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20 % of the zonal mean values. During winter, the wave one in O3* shows a maximum over the North Pacific/Aleutians and a minimum over the North Atlantic/Northern Europe and a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from the lower stratosphere to the upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave patterns occur mainly during southern spring. By comparing the observed wave patterns in O3* and H2O* with a linear solution of a steady-state transport equation for a zonally asymmetric tracer component we find that these wave patterns are primarily due to zonally asymmetric transport by geostrophically balanced winds, which are derived from observed temperature profiles. In addition temperature-dependent photochemistry contributes substantially to the spatial structure of the wave pattern in O3* . Further influences, e.g., zonal asymmetries in eddy

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

    Science.gov (United States)

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

    2017-01-01

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

  14. Ozone kinetics in low-pressure discharges

    Science.gov (United States)

    Guerra, Vasco; Marinov, Daniil; Guaitella, Olivier; Rousseau, Antoine

    2012-10-01

    Ozone kinetics is quite well established at atmospheric pressure, due to the importance of ozone in atmospheric chemistry and to the development of industrial ozone reactors. However, as the pressure is decreased and the dominant three-body reactions lose importance, the main mechanisms involved in the creation and destruction of ozone are still surrounded by important uncertainties. In this work we develop a self-consistent model for a pulsed discharge and its afterglow operating in a Pyrex reactor with inner radius 1 cm, at pressures in the range 1-5 Torr and discharge currents of 40-120 mA. The model couples the electron Boltzmann equation with a system of equations for the time evolution of the heavy particles. The calculations are compared with time-dependent measurements of ozone and atomic oxygen. Parametric studies are performed in order to clarify the role of vibrationally excited ozone in the overall kinetics and to establish the conditions where ozone production on the surface may become important. It is shown that vibrationally excited ozone does play a significant role, by increasing the time constants of ozone formation. Moreover, an upper limit for the ozone formation at the wall in these conditions is set at 10(-4).

  15. Effects of Cosmic Rays on Atmospheric Chlorofluorocarbon Dissociation and Ozone Depletion

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Q.-B.; Sanche, L.

    2001-08-13

    Data from satellite, balloon, and ground-station measurements show that ozone loss is strongly correlated with cosmic-ray ionization-rate variations with altitude, latitude, and time. Moreover, our laboratory data indicate that the dissociation induced by cosmic rays for CF{sub 2}Cl {sub 2} and CFCl{sub 3} on ice surfaces in the polar stratosphere at an altitude of {approx}15 km is quite efficient, with estimated rates of 4.3 x 10{sup -5} and 3.6 x 10{sup -4} s{sup -1}, respectively. These findings suggest that dissociation of chlorofluorocarbons by capture of electrons produced by cosmic rays and localized in polar stratospheric cloud ice may play a significant role in causing the ozone hole.

  16. Atmospheric ozone determination by solar occultation using the UV spectrometer on the Solar Maximum Mission

    Science.gov (United States)

    Aikin, A. C.; Woodgate, B.; Smith, H. J. P.

    1982-01-01

    The UV spectrometer polarimeter instrument on the Solar Maximum Mission spacecraft has been used to measure ozone in the 53-75 km altitude interval by the technique of solar occultation. A 1 x 180 arcsec entrance aperture spectrometer with 0.04-A spectral resolution was employed. Resulting high-quality data are reduced by expressing measured UV attenuation as a Volterra integral equation. Solution of the equation is accomplished by expressing the integral in terms of a series representing the sum of ozone densities contained in concentric shells through tangent points separated by specified altitude increments. Sample ozone vs altitude profiles are presented for the equatorial region. These data show reproducibility to better than 10%. The density at 60 km is 7.3 + or - 0.15 x 10 to the 9th/cu cm for 2.5 deg latitude and longitudes between 81 and 105 deg west in September 1980. Density vs altitude profile exhibits changes in slope between 50 and 75 km.

  17. Regional ozone impacts of increased natural gas use in the Texas power sector and development in the Eagle Ford shale.

    Science.gov (United States)

    Pacsi, Adam P; Kimura, Yosuke; McGaughey, Gary; McDonald-Buller, Elena C; Allen, David T

    2015-03-17

    The combined emissions and air quality impacts of electricity generation in the Texas grid and natural gas production in the Eagle Ford shale were estimated at various natural gas price points for the power sector. The increased use of natural gas in the power sector, in place of coal-fired power generation, drove reductions in average daily maximum 8 h ozone concentration of 0.6-1.3 ppb in northeastern Texas for a high ozone episode used in air quality planning. The associated increase in Eagle Ford upstream oil and gas production nitrogen oxide (NOx) emissions caused an estimated local increase, in south Texas, of 0.3-0.7 ppb in the same ozone metric. In addition, the potential ozone impacts of Eagle Ford emissions on nearby urban areas were estimated. On the basis of evidence from this work and a previous study on the Barnett shale, the combined ozone impact of increased natural gas development and use in the power sector is likely to vary regionally and must be analyzed on a case by case basis.

  18. Fiber-Optic Coupled Lidar Receiver System to Measure Stratospheric Ozone

    Science.gov (United States)

    Harper, David Brent; Elsayed-Ali, Hani

    1998-01-01

    The measurement of ozone in the atmosphere has become increasingly important over the past two decades. Significant increases of ozone concentrations in the lower atmosphere, or troposphere, and decreases in the upper atmosphere, or stratosphere, have been attributed to man-made causes. High ozone concentrations in the troposphere pose a health hazard to plants and animals and can add to global warming. On the other hand, ozone in the stratosphere serves as a protective barrier against strong ultraviolet (UV) radiation from the sun. Man-made CFC's (chlorofluorocarbons) act as a catalyst with a free oxygen atom and an ozone molecule to produce two oxygen molecules therefore depleting the protective layer of ozone in the stratosphere. The beneficial and harmful effects of ozone require the study of ozone creation and destruction processes in the atmosphere. Therefore, to provide an accurate model of these processes, an ozone lidar system must be able to be used frequently with as large a measurement range as possible. Various methods can be used to measure atmospheric ozone concentrations. These include different airborne and balloon measurements, solar occulation satellite techniques, and the use of lasers in lidar (high detection and ranging,) systems to probe the atmosphere. Typical devices such as weather balloons can only measure within the direct vicinity of the instrument and are therefore used infrequently. Satellites use solar occulation techniques that yield low horizontal and vertical resolution column densities of ozone.

  19. Stratospheric ozone fluctuation and ultraviolet radiation over Serbia

    Directory of Open Access Journals (Sweden)

    Nikolić Jugoslav L.

    2011-01-01

    Full Text Available Increased ultraviolet radiation potentially detrimental to health is a direct effect of the reduced ozone layer of the Earth’s atmosphere. Stratospheric ozone over the territory of Serbia and immediate surrounding depleted in the considered period of 1979-2008; its amount reduced by 7.6%. Solar and volcanic activities have significant effect on the interannual variability of the stratospheric ozone. Ozone layer over Serbia is 13.8% thicker than the planetary layer, with the ozone hole forming once in five years on average without serious health implications.

  20. The signs of Antarctic ozone hole recovery.

    Science.gov (United States)

    Kuttippurath, Jayanarayanan; Nair, Prijitha J

    2017-04-03

    Absorption of solar radiation by stratospheric ozone affects atmospheric dynamics and chemistry, and sustains life on Earth by preventing harmful radiation from reaching the surface. Significant ozone losses due to increases in the abundances of ozone depleting substances (ODSs) were first observed in Antarctica in the 1980s. Losses deepened in following years but became nearly flat by around 2000, reflecting changes in global ODS emissions. Here we show robust evidence that Antarctic ozone has started to recover in both spring and summer, with a recovery signal identified in springtime ozone profile and total column measurements at 99% confidence for the first time. Continuing recovery is expected to impact the future climate of that region. Our results demonstrate that the Montreal Protocol has indeed begun to save the Antarctic ozone layer.

  1. Assessment of atmospheric processes driving ozone variations in the subtropical North Atlantic free troposphere

    Directory of Open Access Journals (Sweden)

    E. Cuevas

    2013-02-01

    Full Text Available An analysis of the 22-yr ozone (O3 series (1988–2009 at the subtropical high mountain Izaña~station (IZO; 2373 m a.s.l., representative of free troposphere (FT conditions, is presented. Diurnal and seasonal O3 variations as well as the O3 trend (0.19 ± 0.05 % yr−1 or 0.09 ppbv yr−1, are assessed. A climatology of O3 transport pathways using backward trajectories shows that higher O3 values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O3 is transported from the Saharan continental boundary layer (CBL. O3 data have been compared with PM10, 210Pb, 7Be, potential vorticity (PV and carbon monoxide (CO. A clear negative logarithmic relationship was observed between PM10 and surface O3 for all seasons. A similar relationship was found between O3 and 210Pb. The highest daily O3 values (90th percentile are observed in spring and in the first half of summer time. A positive correlation between O3 and PV, and between O3 and 7Be is found throughout the year, indicating that relatively high surface O3 values at IZO originate from the middle and upper troposphere. We find a good correlation between O3 and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O3 from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O3 values seem to be the result of stratosphere-to-troposphere (STT exchange processes in regions neighbouring the Canary Islands. Since 1995–1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative

  2. Increase of exhaled nitric oxide in children exposed to low levels of ambient ozone.

    Science.gov (United States)

    Nickmilder, Marc; de Burbure, Claire; Carbonnelle, Sylviane; Sylviane, Carbonnelle; Dumont, Xavier; Xavier, Dumont; Bernard, Alfred; Alfred, Bernard; Derouane, Alain; Alain, Derouane

    2007-02-01

    Ozone (O3) is known to induce lung function impairment and airways inflammation during episodes of photochemical smog. The aim of the present study was to assess the inflammatory effect of ambient O3 in healthy children using nitric oxide in exhaled air (eNO) as a noninvasive test. The study was performed on 6 groups of children (n = 11-15), aged 6.5 to 15 yr, who attended summer camps in rural areas of the south of Belgium in 2002. Ambient O3 concentrations continuously monitored in the camps ranged from 48 to 221 microg/m3 (1-h maximal concentration). Children remained outdoors during the experimental days, doing various recreational activities but no sports. Lung function tests (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) and eNO were measured twice in each child in the morning and in the evening. While lung function tests did not show any consistent pattern of decrease at these O3 levels, a highly significant increase in eNO was found in all subjects from an ambient 1-h O3 level of 167 microg/m3. A multivariate analysis did not reveal any influence of age, gender, height, weight, and body mass index (BMI) of the children. The threshold for this O3-induced increase in eNO estimated benchmark dose analysis was 135 microg/m3 for 1-h exposure and 110 microg/m3 for 8-h exposure. These observations suggest that ambient ozone produces early inflammatory changes in the airways of children at levels slightly below current air quality standards.

  3. Inferring ozone production in an urban atmosphere using measurements of peroxynitric acid

    Directory of Open Access Journals (Sweden)

    K. M. Spencer

    2009-06-01

    Full Text Available Observations of peroxynitric acid (HO2NO2 obtained simultaneously with those of NO and NO2 provide a sensitive measure of the ozone photochemical production rate. We illustrate this technique for constraining the ozone production rate with observations obtained from the NCAR C-130 aircraft platform during the Megacity Initiative: Local and Global Research Observations (MILAGRO intensive in Mexico during the spring of 2006. Sensitive and selective measurements of HO2NO2 were made in situ using chemical ionization mass spectrometry (CIMS. Observations were compared to modeled HO2NO2 concentrations obtained from the NASA Langley highly-constrained photochemical time-dependent box model. The median observed-to-calculated ratio of HO2NO2 is 1.18. At NOx levels greater than 15 ppbv, the photochemical box model underpredicts observations with an observed-to-calculated ratio of HO2NO2 of 1.57. As a result, we find that at high NOx, the ozone production rate calculated using measured HO2NO2 is faster than predicted using accepted photochemistry. Inclusion of an additional HOx source from the reaction of excited state NO2 with H2O or reduction in the rate constant of the reaction of OH with NO2 improves the agreement.

  4. Increased CCL24/eotaxin-2 with postnatal ozone exposure in allergen-sensitized infant monkeys is not associated with recruitment of eosinophils to airway mucosa

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Debbie L.; Gerriets, Joan E. [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Schelegle, Edward S.; Hyde, Dallas M. [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616 (United States); Miller, Lisa A., E-mail: lmiller@ucdavis.edu [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616 (United States)

    2011-12-15

    Epidemiology supports a causal link between air pollutant exposure and childhood asthma, but the mechanisms are unknown. We have previously reported that ozone exposure can alter the anatomic distribution of CD25+ lymphocytes in airways of allergen-sensitized infant rhesus monkeys. Here, we hypothesized that ozone may also affect eosinophil trafficking to allergen-sensitized infant airways. To test this hypothesis, we measured blood, lavage, and airway mucosa eosinophils in 3-month old monkeys following cyclical ozone and house dust mite (HDM) aerosol exposures. We also determined if eotaxin family members (CCL11, CCL24, CCL26) are associated with eosinophil location in response to exposures. In lavage, eosinophil numbers increased in animals exposed to ozone and/or HDM. Ozone + HDM animals showed significantly increased CCL24 and CCL26 protein in lavage, but the concentration of CCL11, CCL24, and CCL26 was independent of eosinophil number for all exposure groups. In airway mucosa, eosinophils increased with exposure to HDM alone; comparatively, ozone and ozone + HDM resulted in reduced eosinophils. CCL26 mRNA and immunofluorescence staining increased in airway mucosa of HDM alone animals and correlated with eosinophil volume. In ozone + HDM animal groups, CCL24 mRNA and immunofluorescence increased along with CCR3 mRNA, but did not correlate with airway mucosa eosinophils. Cumulatively, our data indicate that ozone exposure results in a profile of airway eosinophil migration that is distinct from HDM mediated pathways. CCL24 was found to be induced only by combined ozone and HDM exposure, however expression was not associated with the presence of eosinophils within the airway mucosa. -- Highlights: Black-Right-Pointing-Pointer Ozone can modulate the localization of eosinophils in infant allergic airways. Black-Right-Pointing-Pointer Expression of eotaxins within the lung is affected by ozone and allergen exposure. Black-Right-Pointing-Pointer CCL24 induction by

  5. Increasing stomatal conductance in response to rising atmospheric CO2.

    Science.gov (United States)

    Purcell, C; Batke, S P; Yiotis, C; Caballero, R; Soh, W K; Murray, M; McElwain, J C

    2018-01-31

    Studies have indicated that plant stomatal conductance (gs) decreases in response to elevated atmospheric CO2, a phenomenon of significance for the global hydrological cycle. However, gs increases across certain CO2 ranges have been predicted by optimization models. The aim of this work was to demonstrate that under certain environmental conditions, gs can increase in response to elevated CO2. Using (1) an extensive, up-to-date synthesis of gs responses in free air CO2 enrichment (FACE)experiments, (2) in situ measurements across four biomes showing dynamic gs responses to a CO2 rise of ~50 ppm (characterizing the change in this greenhouse gas over the past three decades) and (3) a photosynthesis-stomatal conductance model, it is demonstrated that gs can in some cases increase in response to increasing atmospheric CO2. Field observations are corroborated by an extensive synthesis of gs responses in FACE experiments showing that 11.8 % of gs responses under experimentally elevated CO2 are positive. They are further supported by a strong data-model fit (r2 = 0.607) using a stomatal optimization model applied to the field gs dataset. A parameter space identified in the Farquhar-Ball-Berry photosynthesis-stomatal conductance model confirms field observations of increasing gs under elevated CO2 in hot dry conditions. Contrary to the general assumption, positive gs responses to elevated CO2, although relatively rare, are a feature of woody taxa adapted to warm, low-humidity conditions, and this response is also demonstrated in global simulations using the Community Land Model (CLM4). The results contradict the over-simplistic notion that global vegetation always responds with decreasing gs to elevated CO2, a finding that has important implications for predicting future vegetation feedbacks on the hydrological cycle at the regional level.

  6. The contribution to nitrogen deposition and ozone formation in South Norway from atmospheric emissions related to the petroleum activity in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Solberg, S.; Walker, S.-E.; Knudsen, S.; Lazaridis, M.; Beine, H.J.; Semb, A

    1999-03-01

    A photochemical plume model has been developed and refined. The model is designed to simulate the advection and photochemistry for several simultaneous point sources as well as the atmospheric mixing. the model has been used to calculate nitrogen deposition and ozone formation due to offshore emissions in the North Sea. Based on meteorological data for 1992 the calculations give a total contribution of 60-80 mg (N)/m{sub 2} at most in South Norway. Emission from British and Norwegian sector is calculated to contribute less than 5% each to the AOT40 index for ozone. (author)

  7. Eco-physiological Effects of Atmospheric Ozone and Polycyclic Aromatic Hydrocarbons (PAHs) on Plants

    Science.gov (United States)

    Bandai, S.; Sakugawa, H. H.

    2012-12-01

    [Introduction] Tropospheric ozone is one of most concerned air pollutant, by causing damage to trees and crops. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants found in various environmental compartments. Photo-induced toxicity of PAHs can be driven from formation of intracellular single oxygen and other reactive oxygen intermediates (ROI) leading to biological damages.(1) In the present study, we measured photosynthesis rate and other variables to investigate the effects of ozone and PAHs on the eco-physiological status of plants such as eggplant, common bean and strawberry. Plants treated with the single or combined air pollutants are expected to exhibit altered physiological, morphological and possibly growth changes. [Materials and Methods] We performed three exposure experiments. Exp.1. Eggplant (Solanum melongena) seedlings, were placed in the open-top chambers (n=6 plants/treatment). Treatment system was ozone (O)(120ppb), phenanthrene (P)(10μM), O+P, fluoranthene (F)(10μM), O+F, mannitol (M)(1mM) and the control (Milli-Q water)(C). P, F and M were sprayed three times weekly on the foliage part of eggplant. Average volume sprayed per seedling was 50mL. The treatment period was 30days and [AOT 40 (Accumulated exposure over a threshold of 40 ppb)]=28.8 ppmh. Exp.2, Common bean (Phaseolus vulgaris L.) seedlings were used (n=5 plants/treatment). The treatment system was the same as Exp.1. The treatment period was 40days and [AOT 40]=38.4ppmh. Exp.3. Strawberry (Fragaria L.) seedlings were used (n=5 plants/treatment). Treatment system was O (120ppb), F(10μM), O+F, F+M, O+M and C. The treatment period was 90days and [AOT 40]=86.4ppmh. Ecophysiological variables examined were photosynthesis rate measured at saturated irradiance (Amax), stomatal conductance to water vapour (gs), internal CO2 concentration (Ci), photochemical efficiency of PS2 in the dark (Fv/Fm), chlorophyll contents, visual symptom assessment and elemental composition in the

  8. Overt and Latent Cardiac Effects of Ozone Inhalation in Rats: Evidence for Autonomic Modulation and Increased Myocardial Vulnerability*

    Science.gov (United States)

    Ozone (O3) is a well-documented respiratory oxidant, but increasing epidemiologic evidence points to extra-pulmonary effects including positive associations between ambient O3 concentrations and cardiovascular morbidity/mortality. With preliminary reports linking O3 exposure wit...

  9. Potential of temperature, controlled atmospheres, and ozone fumigation to control thrips and mealybugs on ornamental plants for export.

    Science.gov (United States)

    Hollingsworth, Robert G; Armstrong, John W

    2005-04-01

    Ozone (O3) fumigation is a potential quarantine treatment alternative for controlling stored-product pests and surface insect pests on fresh agricultural commodities. We explored the effects of temperature, treatment time, controlled atmospheres, and vacuum in combination with O3 to control two important pests of ornamental crops: western flower thrips, Frankliniella occidentalis (Pergande), and longtailed mealybug, Pseudococcus longispinus Targioni Tozzetti. Treatment parameters tested were O3 concentrations from 0 to 3,800 ppm, treatment durations were from 30 to 120 min, vacuums were from 0 to 0.41 bar below ambient, temperatures were from 32.2 to 40.6 degrees C, and controlled atmospheres were composed primarily of nitrogen, carbon dioxide, or breathing air [BA]. Treatment efficacy was enhanced by higher O3 concentration and temperature, lower oxygen, and longer treatment times. Reduced pressure was not an important factor. Mealybugs were more difficult to kill than thrips. A 30-min treatment of O3 at approximately 200 ppm in 100% CO2 at 37.8 degrees C killed 47.9 and 98.0% of mealybugs and adult female thrips, respectively. All of the ornamentals tested were damaged to some degree by O3 treatments. However, crops with thick leaves such as orchids exhibited little damage, and the waxy portions of certain flowers were not damaged. The results suggest that O3 has potential as a quarantine treatment to control thrips and mealybugs on selected commodities.

  10. Effects of ozone-vegetation coupling on surface ozone air quality via biogeochemical and meteorological feedbacks

    Science.gov (United States)

    Sadiq, Mehliyar; Tai, Amos P. K.; Lombardozzi, Danica; Martin, Maria Val

    2017-02-01

    Tropospheric ozone is one of the most hazardous air pollutants as it harms both human health and plant productivity. Foliage uptake of ozone via dry deposition damages photosynthesis and causes stomatal closure. These foliage changes could lead to a cascade of biogeochemical and biogeophysical effects that not only modulate the carbon cycle, regional hydrometeorology and climate, but also cause feedbacks onto surface ozone concentration itself. In this study, we implement a semi-empirical parameterization of ozone damage on vegetation in the Community Earth System Model to enable online ozone-vegetation coupling, so that for the first time ecosystem structure and ozone concentration can coevolve in fully coupled land-atmosphere simulations. With ozone-vegetation coupling, present-day surface ozone is simulated to be higher by up to 4-6 ppbv over Europe, North America and China. Reduced dry deposition velocity following ozone damage contributes to ˜ 40-100 % of those increases, constituting a significant positive biogeochemical feedback on ozone air quality. Enhanced biogenic isoprene emission is found to contribute to most of the remaining increases, and is driven mainly by higher vegetation temperature that results from lower transpiration rate. This isoprene-driven pathway represents an indirect, positive meteorological feedback. The reduction in both dry deposition and transpiration is mostly associated with reduced stomatal conductance following ozone damage, whereas the modification of photosynthesis and further changes in ecosystem productivity are found to play a smaller role in contributing to the ozone-vegetation feedbacks. Our results highlight the need to consider two-way ozone-vegetation coupling in Earth system models to derive a more complete understanding and yield more reliable future predictions of ozone air quality.

  11. Global 3-D modeling of atmospheric ozone in the free troposphere and the stratosphere with emphasis on midlatitude regions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Brasseur, G.; Tie, X.; Walters, S.

    1999-03-01

    The authors have used several global chemical/transport models (1) to study the contribution of various physical, chemical, and dynamical processes to the budget of mid-latitude ozone in the stratosphere and troposphere; (2) to analyze the potential mechanisms which are responsible for the observed ozone perturbations at mid-latitudes of the lower stratosphere and in the upper troposphere; (3) to calculate potential changes in atmospheric ozone response to anthropogenic changes (e.g., emission of industrially manufactured CFCs, CO, and NO{sub x}) and to natural perturbations (e.g., volcanic eruptions and biomass burning); and (4) to estimate the impact of these changes on the radiative forcing to the climate system and on the level of UV-B radiation at the surface.

  12. Antarctic Ozone Hole, 2000

    Science.gov (United States)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  13. Surface recombination of oxygen atoms in O2 plasma at increased pressure: II. Vibrational temperature and surface production of ozone

    Science.gov (United States)

    Lopaev, D. V.; Malykhin, E. M.; Zyryanov, S. M.

    2011-01-01

    Ozone production in an oxygen glow discharge in a quartz tube was studied in the pressure range of 10-50 Torr. The O3 density distribution along the tube diameter was measured by UV absorption spectroscopy, and ozone vibrational temperature TV was found comparing the calculated ab initio absorption spectra with the experimental ones. It has been shown that the O3 production mainly occurs on a tube surface whereas ozone is lost in the tube centre where in contrast the electron and oxygen atom densities are maximal. Two models were used to analyse the obtained results. The first one is a kinetic 1D model for the processes occurring near the tube walls with the participation of the main particles: O(3P), O2, O2(1Δg) and O3 molecules in different vibrational states. The agreement of O3 and O(3P) density profiles and TV calculated in the model with observed ones was reached by varying the single model parameter—ozone production probability (\\gamma_{O_{3}}) on the quartz tube surface on the assumption that O3 production occurs mainly in the surface recombination of physisorbed O(3P) and O2. The phenomenological model of the surface processes with the participation of oxygen atoms and molecules including singlet oxygen molecules was also considered to analyse \\gamma_{O_{3}} data obtained in the kinetic model. A good agreement between the experimental data and the data of both models—the kinetic 1D model and the phenomenological surface model—was obtained in the full range of the studied conditions that allowed consideration of the ozone surface production mechanism in more detail. The important role of singlet oxygen in ozone surface production was shown. The O3 surface production rate directly depends on the density of physisorbed oxygen atoms and molecules and can be high with increasing pressure and energy inputted into plasma while simultaneously keeping the surface temperature low enough. Using the special discharge cell design, such an approach opens up the

  14. Increased soil emissions of potent greenhouse gases under increased atmospheric CO2.

    Science.gov (United States)

    van Groenigen, Kees Jan; Osenberg, Craig W; Hungate, Bruce A

    2011-07-13

    Increasing concentrations of atmospheric carbon dioxide (CO(2)) can affect biotic and abiotic conditions in soil, such as microbial activity and water content. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N(2)O) and methane (CH(4)) (refs 2, 3). However, studies on fluxes of N(2)O and CH(4) from soil under increased atmospheric CO(2) have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO(2) (ranging from 463 to 780 parts per million by volume) stimulates both N(2)O emissions from upland soils and CH(4) emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO(2) concentrations. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated. ©2011 Macmillan Publishers Limited. All rights reserved

  15. Effect of greenhouse gas emissions on stratospheric ozone depletion

    NARCIS (Netherlands)

    Velders GJM; LLO

    1997-01-01

    The depletion of the ozone layer is caused mainly by the increase in emissions of chlorine- and bromine-containing compounds like CFCs, halons, carbon tetrachloride, methyl chloroform and methyl bromide. Emissions of greenhouse gases can affect the depletion of the ozone layer through atmospheric

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

    Directory of Open Access Journals (Sweden)

    Jennifer M Albertine

    Full Text Available 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.

  17. Extreme events in total ozone over Arosa: Application of extreme value theory and fingerprints of atmospheric dynamics and chemistry and their effects on mean values and long-term changes

    Science.gov (United States)

    Rieder, Harald E.; Staehelin, Johannes; Maeder, Jörg A.; Peter, Thomas; Ribatet, Mathieu; Davison, Anthony C.; Stübi, Rene; Weihs, Philipp; Holawe, Franz

    2010-05-01

    In this study tools from extreme value theory (e.g. Coles, 2001; Ribatet, 2007) are applied for the first time in the field of stratospheric ozone research, as statistical analysis showed that previously used concepts assuming a Gaussian distribution (e.g. fixed deviations from mean values) of total ozone data do not address the internal data structure concerning extremes adequately. The study illustrates that tools based on extreme value theory are appropriate to identify ozone extremes and to describe the tails of the world's longest total ozone record (Arosa, Switzerland - for details see Staehelin et al., 1998a,b) (Rieder et al., 2010a). A daily moving threshold was implemented for consideration of the seasonal cycle in total ozone. The frequency of days with extreme low (termed ELOs) and extreme high (termed EHOs) total ozone and the influence of those on mean values and trends is analyzed for Arosa total ozone time series. The results show (a) an increase in ELOs and (b) a decrease in EHOs during the last decades and (c) that the overall trend during the 1970s and 1980s in total ozone is strongly dominated by changes in these extreme events. After removing the extremes, the time series shows a strongly reduced trend (reduction by a factor of 2.5 for trend in annual mean). Furthermore, it is shown that the fitted model represents the tails of the total ozone data set with very high accuracy over the entire range (including absolute monthly minima and maxima). Also the frequency distribution of ozone mini-holes (using constant thresholds) can be calculated with high accuracy. Analyzing the tails instead of a small fraction of days below constant thresholds provides deeper insight in time series properties. Excursions in the frequency of extreme events reveal "fingerprints" of dynamical factors such as ENSO or NAO, and chemical factors, such as cold Arctic vortex ozone losses, as well as major volcanic eruptions of the 20th century (e.g. Gunung Agung, El Chich

  18. The ozone hole causes climate changes; Ozonhullet gir klimaendring

    Energy Technology Data Exchange (ETDEWEB)

    Groenaas, Sigbjoern

    2004-07-01

    The importance of ozone initiates discussions about how much of the climate variations the last decades that is due to increased greenhouse effect and how much is due to the loss of ozone. It is thought to be an established fact that the Antarctic ozone hole is mainly created by anthropogenic emission of certain gases that break down the ozone. Researchers now consider that the ozone hole above the Antarctic has affected the atmospheric circulation considerably. Observations have shown that climate variations at higher latitudes in the southern hemisphere during the last decades have been dominated by a strengthening of the westerly winds, a circulation reaching from the surface into the stratosphere. The same changes have been calculated by means of a climate model with ozone variations as the sole driving input. The results show that emissions of gases that damage the ozone layer also cause considerable climatic changes, not only in the stratosphere, but also at the earth's surface.

  19. Long-term leaf production response to elevated atmospheric carbon dioxide and tropospheric ozone

    Science.gov (United States)

    Alan F. Talhelm; Kurt S. Pregitzer; Christian P. Giardina

    2011-01-01

    Elevated concentrations of atmospheric CO2 and tropospheric O3 will profoundly influence future forest productivity, but our understanding of these influences over the long-term is poor. Leaves are key indicators of productivity and we measured the mass, area, and nitrogen concentration of leaves collected in litter traps...

  20. Factors that increase the electric field of the dielectric barrier ozone generators

    Science.gov (United States)

    Ganea, I.; Morar, R.

    2017-05-01

    The dielectric barrier discharge cell (DBDC), also called ozone cell, is the main component of the ozone generators widely used. When the cell is powered with a high voltage value (> 5 kV) in the dielectric gas, arises a high intensity electric field that influences ozone generation processes by silent discharge also called dielectric barrier discharge. The intensity of the electric field depends by a number of factors such as the constructive form of the cell, the cell sizes, the value and the waveform of the supply voltage, the type of insulators used as dielectric barrier. The insulators which constituting the dielectric barrier, influence the intensity of the electric field through the dielectric constant of the liquid or solid shows the values of intensity electrical fields from ozone cells, with plane electrodes and ozone cells with cylindrical electrodes. The paper presents a graphic variation of the electric field from the gap and the dielectric barrier of cells with plane electrodes and cylindrical collinear electrodes. Experimental research highlights current-voltage characteristic for several types of dielectrics. Distilled water was highlighted as dielectric with the best results.

  1. Impact of a future H2-based road transportation sector on the composition and chemistry of the atmosphere - Part 2: Stratospheric ozone

    Science.gov (United States)

    Wang, D.; Jia, W.; Olsen, S. C.; Wuebbles, D. J.; Dubey, M. K.; Rockett, A. A.

    2013-07-01

    The prospective future adoption of molecular hydrogen (H2) to power the road transportation sector could greatly improve tropospheric air quality but also raises the question of whether the adoption would have adverse effects on the stratospheric ozone. The possibility of undesirable impacts must be fully evaluated to guide future policy decisions. Here we evaluate the possible impact of a future (2050) H2-based road transportation sector on stratospheric composition and chemistry, especially on the stratospheric ozone, with the MOZART (Model for OZone And Related chemical Tracers) model. Since future growth is highly uncertain, we evaluate the impact of two world evolution scenarios, one based on an IPCC (Intergovernmental Panel on Climate Change) high-emitting scenario (A1FI) and the other on an IPCC low-emitting scenario (B1), as well as two technological options: H2 fuel cells and H2 internal combustion engines. We assume a H2 leakage rate of 2.5% and a complete market penetration of H2 vehicles in 2050. The model simulations show that a H2-based road transportation sector would reduce stratospheric ozone concentrations as a result of perturbed catalytic ozone destruction cycles. The magnitude of the impact depends on which growth scenario evolves and which H2 technology option is applied. For the evolution growth scenario, stratospheric ozone decreases more in the H2 fuel cell scenarios than in the H2 internal combustion engine scenarios because of the NOx emissions in the latter case. If the same technological option is applied, the impact is larger in the A1FI emission scenario. The largest impact, a 0.54% decrease in annual average global mean stratospheric column ozone, is found with a H2 fuel cell type road transportation sector in the A1FI scenario; whereas the smallest impact, a 0.04% increase in stratospheric ozone, is found with applications of H2 internal combustion engine vehicles in the B1 scenario. The impacts of the other two scenarios fall

  2. Impact of a future H2-based road transportation sector on the composition and chemistry of the atmosphere – Part 2: Stratospheric ozone

    Directory of Open Access Journals (Sweden)

    D. Wang

    2013-07-01

    Full Text Available The prospective future adoption of molecular hydrogen (H2 to power the road transportation sector could greatly improve tropospheric air quality but also raises the question of whether the adoption would have adverse effects on the stratospheric ozone. The possibility of undesirable impacts must be fully evaluated to guide future policy decisions. Here we evaluate the possible impact of a future (2050 H2-based road transportation sector on stratospheric composition and chemistry, especially on the stratospheric ozone, with the MOZART (Model for OZone And Related chemical Tracers model. Since future growth is highly uncertain, we evaluate the impact of two world evolution scenarios, one based on an IPCC (Intergovernmental Panel on Climate Change high-emitting scenario (A1FI and the other on an IPCC low-emitting scenario (B1, as well as two technological options: H2 fuel cells and H2 internal combustion engines. We assume a H2 leakage rate of 2.5% and a complete market penetration of H2 vehicles in 2050. The model simulations show that a H2-based road transportation sector would reduce stratospheric ozone concentrations as a result of perturbed catalytic ozone destruction cycles. The magnitude of the impact depends on which growth scenario evolves and which H2 technology option is applied. For the evolution growth scenario, stratospheric ozone decreases more in the H2 fuel cell scenarios than in the H2 internal combustion engine scenarios because of the NOx emissions in the latter case. If the same technological option is applied, the impact is larger in the A1FI emission scenario. The largest impact, a 0.54% decrease in annual average global mean stratospheric column ozone, is found with a H2 fuel cell type road transportation sector in the A1FI scenario; whereas the smallest impact, a 0.04% increase in stratospheric ozone, is found with applications of H2 internal combustion engine vehicles in the B1 scenario. The impacts of the other two

  3. Sporadic increases in lunar atmospheric helium detected by LAMP

    Science.gov (United States)

    Cook, Jason C.; Alan Stern, S.

    2014-07-01

    We report on a multi-year dataset of daily averaged observations of He in the lunar atmosphere by the LAMP UV spectrograph on NASA’s Lunar Reconnaissance Orbiter (LRO). We examine data obtained from the start of the LRO orbital tour in September 2009 to March 2013. We find that the maximum He number density occurs about two hours after local midnight, which is consistent with earlier measurements by the Apollo ALSEP LACE mass spectrometer. However, our measured maximum He density is 2-3 times lower than that of LACE. We also observed several instances where the surface He number density rapidly increased to higher than normal values and then declined for several days. We term these events “He flares”. We examined several plausible causes of these events, and found two plausible mechanisms that could be responsible for generating them. One is that the He may be generated by strong, coincident bursts of α particles in the solar wind. To do so, we compare our observations with solar wind α particle observations by ARTEMIS (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun). Another plausible cause we discuss is that the He in the flares may be released from the Moon itself via moonquakes. Determining which is actually the cause requires further work and new measurements.

  4. Chronic exposure to ozone and nitric acid vapor results in increased levels of rat pulmonary putrescine

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu, R.K.; Kikkawa, Yutaka [Department of Pathology, College of Medicine, University of California at Irvine, Irvine (United States); Mautz, W.J. [Department of Community and Environmental Medicine, University of California at Irvine, Irvine, CA (United States)

    1998-06-01

    In the past decade, there has been growing public concern for the human health effects of exposure to environmental pollutants. Ozone (O{sub 3}) is one of the most reactive components of photochemical air pollution. Despite extensive investigations by many laboratories on the functional, biochemical, and cellular effects of O{sub 3} exposure in humans, animals, and in vitro systems, questions remain concerning the potential adverse effects to human health represented by chronic near-ambient exposure to this environmental pollutant. In the present investigation, the influence of inhalation of O{sub 3} and nitric acid (HNO{sub 3}) vapor on polyamine levels was examined in rat lungs. Male F344/N rats were exposed nose-only to 0.15 ppm O{sub 3} and 50 {mu}g/m{sup 3} HNO{sub 3} vapor alone and in combination for 4 hours/day, 3 days/week for a total of 40 weeks. At this time the animals were sacrificed and their lungs were examined for polyamine contents. Exposure to O{sub 3} and O{sub 3} plus HNO{sub 3} vapor caused a significant increase in the putrescine content of the lung compared to the air-exposed controls (P < 0.05). The concentrations of pulmonary spermidine and spermine were not significantly increased by exposure to either O{sub 3} or HNO{sub 3} vapor alone or in combination compared to the air-exposed controls. The role of polyamines in repair and anti-inflammatory processes has been discussed. (orig.) (orig.) With 1 fig., 1 tab., 30 refs.

  5. Observations of the vertical distributions of summertime atmospheric pollutants and the corresponding ozone production in Shanghai, China

    Directory of Open Access Journals (Sweden)

    C. Xing

    2017-12-01

    Full Text Available Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS and lidar measurements were performed in Shanghai, China, during May 2016 to investigate the vertical distribution of summertime atmospheric pollutants. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO2 and formaldehyde (HCHO concentrations were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO algorithm, while vertical distribution of ozone (O3 was obtained from an ozone lidar. Sensitivity study of the MAX-DOAS aerosol profile retrieval shows that the a priori aerosol profile shape has significant influences on the aerosol profile retrieval. Aerosol profiles retrieved from MAX-DOAS measurements with Gaussian a priori profile demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. Tropospheric NO2 vertical column densities (VCDs measured with MAX-DOAS show a good agreement with OMI satellite observations with a Pearson correlation coefficient (R of 0.95. In addition, measurements of the O3 vertical distribution indicate that the ozone productions do not only occur at surface level but also at higher altitudes (about 1.1 km. Planetary boundary layer (PBL height and horizontal and vertical wind field information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground level and upper altitudes are not directly related to horizontal and vertical transportation. Similar patterns of O3 and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near the surface and at higher altitudes are mainly influenced by the abundance of volatile organic compounds (VOCs in the lower troposphere.

  6. High ozone increases soil perchlorate but does not affect foliar perchlorate content

    Science.gov (United States)

    Ozone (O3) is implicated in the natural source inventory of perchlorate (ClO4-), a hydrophilic salt that migrates to ground water and interferes with uptake of iodide in mammals, including humans. Tropospheric O3 is elevated in many areas. We previously showed (Grantz et al., 2013; Environmental Pol...

  7. The impact of a future H2-based road transportation sector on the composition and chemistry of the atmosphere - Part 2: Stratospheric ozone

    Science.gov (United States)

    Wang, D.; Jia, W.; Olsen, S. C.; Wuebbles, D. J.; Dubey, M. K.; Rockett, A. A.

    2012-08-01

    The prospective future adoption of hydrogen to power the road transportation sector could greatly improve tropospheric air quality but also raises the question whether the adoption would have adverse effects on stratospheric ozone. The possibility of these undesirable impacts must be fully evaluated to guide future policy decisions. Here we evaluate the possible impact of a future (2050) H2-based road transportation sector on stratospheric composition and chemistry, especially on stratospheric ozone, with the MOZART chemical transport model. Since future growth is highly uncertain we evaluate the impact for two world evolution scenarios, one based on a high emitting scenario (IPCC A1FI) and the other on a low emitting scenario (IPCC B1), as well as two technological options: H2 fuel cells and H2 internal combustion engines. We assume a H2 leakage rate of 2.5% and a complete market penetration of H2 vehicles in 2050. The model simulations show that a H2-based road transportation sector would reduce stratospheric ozone concentrations as a result of perturbed catalytic ozone destruction cycles. The magnitude of the impact depends on which growth scenario the world evolves and which H2 technology option is applied. For the same world evolution scenario, stratospheric ozone decreases more in the H2 fuel cell scenarios than in the H2 internal combustion engine scenarios because of the NOx emissions in the latter case. If the same technological option is applied, the impact is larger in the A1FI emission scenario. The largest impact, a 0.54% decrease in annual average global mean stratospheric column ozone, is found with a H2 fuel cell type road transportation sector in the A1FI scenario; whereas the smallest impact, a 0.04% increase in stratospheric ozone, is found with applications of H2 internal combustion engine vehicles in the B1 scenario. The impacts of the other two scenarios fall between the above two bounding scenarios. However, the magnitude of these changes is

  8. Influence of atmospheric oxygen and ozone on ripening indices of normal (Rin) and ripening inhibited (rin) tomato cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, Y.P.; Solberg, M.; Haard, N.F.

    1980-01-01

    Ethylene (10 ppm) dependent mediation of normal and mutant (rin) tomato fruit ripening was promoted by 100% oxygen, 3.7 pphm ozone, or their combination. All ripening indices studied (respiration, chlorophyll degradation, carotenoid accumulation, softening, and aroma development) were promoted by oxygen and/or ozone. Ozone also acted independent of ethylene in promoting chlorophyll degradation and aroma development in normal fruit, but did not appreciably affect these quality attributes in mutant fruit. Lycopene accumulation in normal and mutant fruit and aroma formation in normal fruit were promoted to a greater extent by ozone than were other ripening indices. Mutant (rin) fruit contained 27% of the lycopene that was present in normal (Rin) fruit after ripening in O/sub 2/ containing 10ppm ethylene and 3.7 pphm ozone, whereas they contained only 3% of the lycopene in normal fruit after ripening in air containing 10ppm ethylene.

  9. Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations

    Science.gov (United States)

    Wijaikhum, A.; Schröder, D.; Schröter, S.; Gibson, A. R.; Niemi, K.; Friderich, J.; Greb, A.; Schulz-von der Gathen, V.; O’Connell, D.; Gans, T.

    2017-11-01

    The efficient generation of reactive oxygen species (ROS) in cold atmospheric pressure plasma jets (APPJs) is an increasingly important topic, e.g. for the treatment of temperature sensitive biological samples in the field of plasma medicine. A 13.56 MHz radio-frequency (rf) driven APPJ device operated with helium feed gas and small admixtures of oxygen (up to 1%), generating a homogeneous glow-mode plasma at low gas temperatures, was investigated. Absolute densities of ozone, one of the most prominent ROS, were measured across the 11 mm wide discharge channel by means of broadband absorption spectroscopy using the Hartley band centred at λ = 255 nm. A two-beam setup with a reference beam in Mach–Zehnder configuration is employed for improved signal-to-noise ratio allowing high-sensitivity measurements in the investigated single-pass weak-absorbance regime. The results are correlated to gas temperature measurements, deduced from the rotational temperature of the N2 (C 3 {{{\\Pi }}}u+ \\to B 3 {{{\\Pi }}}g+, υ = 0 \\to 2) optical emission from introduced air impurities. The observed opposing trends of both quantities as a function of rf power input and oxygen admixture are analysed and explained in terms of a zero-dimensional plasma-chemical kinetics simulation. It is found that the gas temperature as well as the densities of O and O2(b{}1{{{Σ }}}g+) influence the absolute O3 densities when the rf power is varied.

  10. An estimate of the global burden of anthropogenic ozone and fine particulate matter on premature human mortality using atmospheric modeling.

    Science.gov (United States)

    Anenberg, Susan C; Horowitz, Larry W; Tong, Daniel Q; West, J Jason

    2010-09-01

    Ground-level concentrations of ozone (O3) and fine particulate matter [model simulations of preindustrial and present-day (2000) concentrations to derive exposure estimates. Attributable mortalities were estimated using health impact functions based on long-term relative risk estimates for O3 and PM2.5 from the epidemiology literature. Using simulated concentrations rather than previous methods based on measurements allows the inclusion of rural areas where measurements are often unavailable and avoids making assumptions for background air pollution. Anthropogenic O3 was associated with an estimated 0.7 +/- 0.3 million respiratory mortalities (6.3 +/- 3.0 million years of life lost) annually. Anthropogenic PM2.5 was associated with 3.5 +/- 0.9 million cardiopulmonary and 220,000 +/- 80,000 lung cancer mortalities (30 +/- 7.6 million years of life lost) annually. Mortality estimates were reduced approximately 30% when we assumed low-concentration thresholds of 33.3 ppb for O3 and 5.8 microg/m3 for PM2.5. These estimates were sensitive to concentration thresholds and concentration-mortality relationships, often by > 50%. Anthropogenic O3 and PM2.5 contribute substantially to global premature mortality. PM2.5 mortality estimates are about 50% higher than previous measurement-based estimates based on common assumptions, mainly because of methodologic differences. Specifically, we included rural populations, suggesting higher estimates; however, the coarse resolution of the global atmospheric model may underestimate urban PM(2.5) exposures.

  11. Future impact of non-land based traffic emissions on atmospheric ozone and OH - an optimistic scenario and a possible mitigation strategy

    Science.gov (United States)

    Hodnebrog, Ø.; Berntsen, T. K.; Dessens, O.; Gauss, M.; Grewe, V.; Isaksen, I. S. A.; Koffi, B.; Myhre, G.; Olivié, D.; Prather, M. J.; Pyle, J. A.; Stordal, F.; Szopa, S.; Tang, Q.; van Velthoven, P.; Williams, J. E.; Ødemark, K.

    2011-11-01

    The impact of future emissions from aviation and shipping on the atmospheric chemical composition has been estimated using an ensemble of six different atmospheric chemistry models. This study considers an optimistic emission scenario (B1) taking into account e.g. rapid introduction of clean and resource-efficient technologies, and a mitigation option for the aircraft sector (B1 ACARE), assuming further technological improvements. Results from sensitivity simulations, where emissions from each of the transport sectors were reduced by 5%, show that emissions from both aircraft and shipping will have a larger impact on atmospheric ozone and OH in near future (2025; B1) and for longer time horizons (2050; B1) compared to recent time (2000). However, the ozone and OH impact from aircraft can be reduced substantially in 2050 if the technological improvements considered in the B1 ACARE will be achieved. Shipping emissions have the largest impact in the marine boundary layer and their ozone contribution may exceed 4 ppbv (when scaling the response of the 5% emission perturbation to 100% by applying a factor 20) over the North Atlantic Ocean in the future (2050; B1) during northern summer (July). In the zonal mean, ship-induced ozone relative to the background levels may exceed 12% near the surface. Corresponding numbers for OH are 6.0 × 105 molecules cm-3 and 30%, respectively. This large impact on OH from shipping leads to a relative methane lifetime reduction of 3.92 (±0.48) on the global average in 2050 B1 (ensemble mean CH4 lifetime is 8.0 (±1.0) yr), compared to 3.68 (±0.47)% in 2000. Aircraft emissions have about 4 times higher ozone enhancement efficiency (ozone molecules enhanced relative to NOx molecules emitted) than shipping emissions, and the maximum impact is found in the UTLS region. Zonal mean aircraft-induced ozone could reach up to 5 ppbv at northern mid- and high latitudes during future summer (July 2050; B1), while the relative impact peaks during

  12. Future impact of non-land based traffic emissions on atmospheric ozone and OH – an optimistic scenario and a possible mitigation strategy

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2011-11-01

    Full Text Available The impact of future emissions from aviation and shipping on the atmospheric chemical composition has been estimated using an ensemble of six different atmospheric chemistry models. This study considers an optimistic emission scenario (B1 taking into account e.g. rapid introduction of clean and resource-efficient technologies, and a mitigation option for the aircraft sector (B1 ACARE, assuming further technological improvements. Results from sensitivity simulations, where emissions from each of the transport sectors were reduced by 5%, show that emissions from both aircraft and shipping will have a larger impact on atmospheric ozone and OH in near future (2025; B1 and for longer time horizons (2050; B1 compared to recent time (2000. However, the ozone and OH impact from aircraft can be reduced substantially in 2050 if the technological improvements considered in the B1 ACARE will be achieved.

    Shipping emissions have the largest impact in the marine boundary layer and their ozone contribution may exceed 4 ppbv (when scaling the response of the 5% emission perturbation to 100% by applying a factor 20 over the North Atlantic Ocean in the future (2050; B1 during northern summer (July. In the zonal mean, ship-induced ozone relative to the background levels may exceed 12% near the surface. Corresponding numbers for OH are 6.0 × 105 molecules cm−3 and 30%, respectively. This large impact on OH from shipping leads to a relative methane lifetime reduction of 3.92 (±0.48 on the global average in 2050 B1 (ensemble mean CH4 lifetime is 8.0 (±1.0 yr, compared to 3.68 (±0.47% in 2000.

    Aircraft emissions have about 4 times higher ozone enhancement efficiency (ozone molecules enhanced relative to NOx molecules emitted than shipping emissions, and the maximum impact is found in the UTLS region. Zonal mean aircraft-induced ozone could reach up to 5 ppbv at northern mid- and high latitudes during

  13. Ozone oil promotes wound healing by increasing the migration of fibroblasts via PI3K/Akt/mTOR signaling pathway.

    Science.gov (United States)

    Xiao, Weirong; Tang, Hua; Wu, Meng; Liao, Yangying; Li, Ke; Li, Lan; Xu, Xiaopeng

    2017-12-22

    Skin injury affects millions of people via the uncontrolled inflammation and infection. Many cellular components including fibroblasts and signaling pathways such as transforming growth factor-β (TGF-β) were activated to facilitate the wound healing to repair injured tissues. C57BL/6 female mice were divided into control and ozone oil treated groups. Excisional wounds were made on the dorsal skin and the fibroblasts were isolated from granulation tissues. The skin injured mouse model revealed that ozone oil could significantly decrease the wound area and accelerate wound healing compared with control group. QPCR and Western blotting assays showed that ozone oil up-regulated collagen I, α-SMA, and TGF-β1 mRNA and protein levels in fibroblasts. Wound healing assay demonstrated that ozone oil could increase the migration of fibroblasts. Western blotting assay demonstrated that ozone oil increased the epithelial-mesenchymal transition (EMT) process in fibroblasts via up-regulating fibronectin, vimentin, N-cadherin, MMP-2, MMP-9, insulin-like growth factor binding protein (IGFBP)-3, IGFBP5, and IGFBP6, and decreasing epithelial protein E-cadherin and cellular senescence marker p16 expression. Mechanistically, Western blotting assay revealed that ozone oil increased the phosphorylation of PI3K, Akt, and mTOR to regulate the EMT process, while inhibition of PI3K reversed this effect of ozone oil. At last, the results from Cytometric Bead Array (CBA) demonstrated ozone oil significantly decreased the inflammation in fibroblasts. Our results demonstrated that ozone oil facilitated the wound healing via increasing fibroblast migration and EMT process via PI3K/Akt/mTOR signaling pathway in vivo and in vitro The cellular and molecular mechanisms we found here may provide new therapeutic targets for the treatment of skin injury. © 2017 The Author(s).

  14. Ozone depletion zone and ozone smog. Ozone chemistry fundamentals. Ozonloch - Ozonsmog. Grundlagen der Ozonchemie

    Energy Technology Data Exchange (ETDEWEB)

    Roeth, E.P.

    1994-01-01

    This book elucidates the fundamentals of the ozone theory. The knowledge verified through measurements is compiled, and the gaps in the knowledge of ozone are defined. While the knowledge of ozone appears to be well-established the gaps in the knowledge are responsible for uncertainties. Measurement methods for determination of the atmospheric concentration of ozone are described. Details are given about the basic processes of atmospheric ozone formation and ozone depletion and about the role of CFC. The factors which determine ozone concentrations in the southern hemisphere are described first because South Pole ozone formation processes, in spite of their complexity, are not as complex as North Pole ozone formation processes. The differences between these processes in the two polar regions are described. (orig.)

  15. Ozone Layer Observations

    Science.gov (United States)

    McPeters, Richard; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The US National Aeronautics and Space Administration (NASA) has been monitoring the ozone layer from space using optical remote sensing techniques since 1970. With concern over catalytic destruction of ozone (mid-1970s) and the development of the Antarctic ozone hole (mid-1980s), long term ozone monitoring has become the primary focus of NASA's series of ozone measuring instruments. A series of TOMS (Total Ozone Mapping Spectrometer) and SBUV (Solar Backscatter Ultraviolet) instruments has produced a nearly continuous record of global ozone from 1979 to the present. These instruments infer ozone by measuring sunlight backscattered from the atmosphere in the ultraviolet through differential absorption. These measurements have documented a 15 Dobson Unit drop in global average ozone since 1980, and the declines in ozone in the antarctic each October have been far more dramatic. Instruments that measure the ozone vertical distribution, the SBUV and SAGE (Stratospheric Aerosol and Gas Experiment) instruments for example, show that the largest changes are occurring in the lower stratosphere and upper troposphere. The goal of ozone measurement in the next decades will be to document the predicted recovery of the ozone layer as CFC (chlorofluorocarbon) levels decline. This will require a continuation of global measurements of total column ozone on a global basis, but using data from successor instruments to TOMS. Hyperspectral instruments capable of measuring in the UV will be needed for this purpose. Establishing the relative roles of chemistry and dynamics will require instruments to measure ozone in the troposphere and in the stratosphere with good vertical resolution. Instruments that can measure other chemicals important to ozone formation and destruction will also be needed.

  16. Ozone-Depleting Gases in the Atmosphere: Results From 28 Years of Measurements by the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL)

    Science.gov (United States)

    Hurst, D. F.; Elkins, J. W.; Montzka, S. A.; Butler, J. H.; Dutton, G. S.; Hall, B. D.; Mondeel, D. J.; Moore, F. L.; Nance, J. D.; Romashkin, P. A.; Thompson, T. M.

    2005-12-01

    Back in 1978, NOAA/CMDL initiated the weekly filling of flasks at CMDL observatories in Alaska, Hawaii, American Samoa, and Antarctica for analyses of CFC-11, CFC-12 and N2O in the home laboratory. A decade later, each observatory was outfitted with an automated gas chromatograph to make routine, in situ measurements of these three source gases plus methyl chloroform and carbon tetrachloride. Both measurement programs are ongoing, having expanded over the years to include methyl halides and substitutes for regulated halocarbons, to presently account for 95% of the total burden of long-lived Cl and Br believed to enter the stratosphere. These long-term monitoring data have been assimilated into temporal records of the global tropospheric burdens of ozone-depleting chlorine and bromine which are critical input to models that predict future trends in stratospheric ozone. Other information pivotal to ozone projections, such as the atmospheric lifetimes of source gases, stratospheric entry values for total chlorine and total bromine, and identification of the stratospheric sink regions for long-lived source gases, has been gained from in situ measurements by NOAA/CMDL instruments aboard NASA high-altitude aircraft (ER-2 and WB-57) and balloons since 1991. Though CMDL's routine monitoring activities provide important historical records of halogenated source gases in the atmosphere, significant inaccuracies in ozone projections may propagate from the uncertain estimates of impending emissions of ozone-depleting gases. Scenarios of future halocarbon emissions require substantial assumptions about past and pending compliance with the Montreal Protocol, and the sizes and release rates of existing global reservoirs (banks) of halocarbons. Recent work by CMDL has focused on quantifying halocarbon bank emission rates in Russia, the USA, and Canada through geographically extensive measurements aboard trains and low-altitude aircraft. The USA and Canada results indicate that

  17. Increasing retention of early career female atmospheric scientists

    Science.gov (United States)

    Edwards, L. M.; Hallar, A. G.; Avallone, L. M.; Thiry, H.

    2010-12-01

    Atmospheric Science Collaborations and Enriching NeTworks (ASCENT) is a workshop series designed to bring together early career female scientists in the field of atmospheric science and related disciplines. ASCENT uses a multi-faceted approach to provide junior scientists with tools that will help them meet the challenges in their research and teaching career paths and will promote their retention in the field. During the workshop, senior women scientists discuss their career and life paths. They also lead seminars on tools, resources and methods that can help early career scientists to be successful and prepared to fill vacancies created by the “baby boomer” retirees. Networking is a significant aspect of ASCENT, and many opportunities for both formal and informal interactions among the participants (of both personal and professional nature) are blended in the schedule. The workshops are held in Steamboat Springs, Colorado, home of a high-altitude atmospheric science laboratory, Storm Peak Laboratory, which also allows for nearby casual outings and a pleasant environment for participants. Near the conclusion of each workshop, junior and senior scientists are matched in mentee-mentor ratios of two junior scientists per senior scientist. Post-workshop reunion events are held at national scientific meetings to maintain connectivity among each year’s participants, and for collaborating among participants of all workshops held to date. Evaluations of the two workshop cohorts thus far conclude that the workshops have been successful in achieving the goals of establishing and expanding personal and research-related networks, and that seminars have been useful in creating confidence and sharing resources for such things as preparing promotion and tenure packages, interviewing and negotiating job offers, and writing successful grant proposals.

  18. The Response of Lower Atmospheric Ozone to ENSO in Aura Measurements and a Chemistry-Climate Simulation

    Science.gov (United States)

    Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Rodriquez, J. M.; Waugh, D. W.; Nielsen, J. E.

    2012-01-01

    The El Nino-Southern Oscillation (ENSO) is the dominant mode of tropical variability on interannual time scales. ENSO appears to extend its influence into the chemical composition of the tropical troposphere. Recent work has revealed an ENSO-induced wave-1 anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this feature using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show composition sensitivity in observations from NASA s Aura satellite Microwave Limb Sounder (MLS) and the Tropospheric Emissions Spectrometer (TES) and a simulation to provide insight into the vertical structure of these ENSO-induced ozone changes. The ozone changes due to the Quasi-Biennial Oscillation (QBO) in the extra-polar upper troposphere and lower stratosphere in MLS measurements will also be discussed.

  19. Modeling the oxidative capacity of the atmosphere of the south coast air basin of California. 1. Ozone formation metrics.

    Science.gov (United States)

    Griffin, Robert J; Revelle, Meghan K; Dabdub, Donald

    2004-02-01

    Metrics associated with ozone (O3) formation are investigated using the California Institute of Technology (CIT) three-dimensional air-quality model. Variables investigated include the O3 production rate (P(O3)), O3 production efficiency (OPE), and total reactivity (the sum of the reactivity of carbon monoxide (CO) and all organic gases that react with the hydroxyl radical). Calculations are spatially and temporally resolved; surface-level and vertically averaged results are shown for September 9, 1993 for three Southern California locations: Central Los Angeles, Azusa, and Riverside. Predictions indicate increasing surface-level O3 concentrations with distance downwind, in line with observations. Surface-level and vertically averaged P(O3) values peak during midday and are highest downwind; surface P(O3) values are greater than vertically averaged values. Surface OPEs generally are highest downwind and peak during midday in downwind locations. In contrast, peaks occur in early morning and late afternoon in the vertically averaged case. Vertically averaged OPEs tend to be greater than those for the surface. Total reactivities are highest in upwind surface locations and peak during rush hours; vertically averaged reactivities are smaller and tend to be more uniform temporally and spatially. Total reactivity has large contributions from CO, alkanes, alkenes, aldehydes, unsubstituted monoaromatics, and secondary organics. Calculations using estimated emissions for 2010 result in decreases in P(O3) values and reactivities but increases in OPEs.

  20. Molecular storage of ozone in a clathrate hydrate: an attempt at preserving ozone at high concentrations.

    Directory of Open Access Journals (Sweden)

    Takahiro Nakajima

    Full Text Available This paper reports an experimental study of the formation of a mixed O(3+ O(2+ CO(2 hydrate and its frozen storage under atmospheric pressure, which aimed to establish a hydrate-based technology for preserving ozone (O(3, a chemically unstable substance, for various industrial, medical and consumer uses. By improving the experimental technique that we recently devised for forming an O(3+ O(2+ CO(2 hydrate, we succeeded in significantly increasing the fraction of ozone contained in the hydrate. For a hydrate formed at a system pressure of 3.0 MPa, the mass fraction of ozone was initially about 0.9%; and even after a 20-day storage at -25°C and atmospheric pressure, it was still about 0.6%. These results support the prospect of establishing an economical, safe, and easy-to-handle ozone-preservation technology of practical use.

  1. Nobel Prize in Chemistry 1995 "for their work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone" : Paul J Crutzen, Mario J Molina and F Sherwood Rowland

    CERN Multimedia

    1997-01-01

    Prof. Paul J Crutzen presents "The stratospheric ozone hole : a man-caused chemical instability".The discovery of the spring time stratospheric ozone hole by scientists of the British Antarctic Survey, led by Joe Farman, was one of the greatest surprises in the history of the atmospheric sciences and global change studies. After intensive research efforts by many international scientific teams it has clearly been demonstrated that the observed rapid ozone depletions are due to catalytic reactions involving CIO radicals, more than 80571130f which are produced by the photochemical breakdown of the industrial chlorofluorocarbon (CFC) gases. In this lecture I will present the course of events leading to the rapid ozone depletions. International agreements have been reached to forbid the production of the CFC gases. However, despite these measures, it will take almost 50 years before the ozone hole will have disappeared. I will also show that mankind has indeed been very lucky and that things could have been far w...

  2. Children's Models of the Ozone Layer and Ozone Depletion.

    Science.gov (United States)

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  3. Increased anion channel activity is an unavoidable event in ozone-induced programmed cell death.

    Directory of Open Access Journals (Sweden)

    Takashi Kadono

    Full Text Available BACKGROUND: Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. PRINCIPAL FINDINGS: By exposing cells to a strong pulse of ozonized air, an acute cell death was observed in suspension cells of Arabidopsis thaliana used as a model. We demonstrated that O(3 treatment induced the activation of a plasma membrane anion channel that is an early prerequisite of O(3-induced cell death in A. thaliana. Our data further suggest interplay of anion channel activation with well known plant responses to O(3, Ca(2+ influx and NADPH-oxidase generated reactive oxygen species (ROS in mediating the oxidative cell death. This interplay might be fuelled by several mechanisms in addition to the direct ROS generation by O(3; namely, H(2O(2 generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death. SIGNIFICANCE: Collectively, our data indicate that anion efflux is an early key component of morphological and biochemical events leading to O(3-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation.

  4. Impact of increasing heat waves on U.S. ozone episodes in the 2050s: Results from a multimodel analysis using extreme value theory

    Science.gov (United States)

    Shen, L.; Mickley, L. J.; Gilleland, E.

    2016-04-01

    We develop a statistical model using extreme value theory to estimate the 2000-2050 changes in ozone episodes across the United States. We model the relationships between daily maximum temperature (Tmax) and maximum daily 8 h average (MDA8) ozone in May-September over 2003-2012 using a Point Process (PP) model. At ~20% of the sites, a marked decrease in the ozone-temperature slope occurs at high temperatures, defined as ozone suppression. The PP model sometimes fails to capture ozone-Tmax relationships, so we refit the ozone-Tmax slope using logistic regression and a generalized Pareto distribution model. We then apply the resulting hybrid-extreme value theory model to projections of Tmax from an ensemble of downscaled climate models. Assuming constant anthropogenic emissions at the present level, we find an average increase of 2.3 d a-1 in ozone episodes (>75 ppbv) across the United States by the 2050s, with a change of +3-9 d a-1 at many sites.

  5. The Antarctic Ozone Hole.

    Science.gov (United States)

    Stolarski, Richard S.

    1988-01-01

    Discusses the Airborne Antarctic Ozone Experiment (1987) and the findings of the British Antarctic Survey (1985). Proposes two theories for the appearance of the hole in the ozone layer over Antarctica which appears each spring; air pollution and natural atmospheric shifts. Illustrates the mechanics of both. Supports worldwide chlorofluorocarbon…

  6. The Role of Lipid Hydroperoxides in Ozone-Induced Increases in Glutathione Redox Potential in Human Airway Epithelial Cells

    Science.gov (United States)

    Human exposure to tropospheric ozone pollution is of global public health concern. Exposure to ozone induces functional decrements and inflammatory responses in the respiratory tract that are thought to occur through oxidative mechanisms. While it is known that ozone oxidizes p...

  7. Ground-level ozone in urban Beijing over a 1-year period: Temporal variations and relationship to atmospheric oxidation

    Science.gov (United States)

    Wang, Zhanshan; Li, Yunting; Chen, Tian; Zhang, Dawei; Sun, Feng; Wei, Qiang; Dong, Xin; Sun, Ruiwen; Huan, Ning; Pan, Libo

    2015-10-01

    Regional ozone pollution has become a major environmental concern in China, especially in densely populated and economically vibrant regions such as North China, including Beijing. To address this issue, surface ozone and its precursors (CO, NO, and NO2) from December 2012 to November 2013 at 12 sites in urban Beijing and 2 sites in suburban Beijing were analyzed. The annual average concentrations of O3, CO, NO, and NO2 in urban Beijing were 45.5 ± 50.2 μg m- 3, 1.5 ± 1.3 mg m- 3, 27.3 ± 42.7 μg m- 3, and 58.3 + 32.0 μg m- 3, respectively. The concentration of ozone was highest during summer, whereas concentrations of its precursors were highest during winter. Diurnal variations in ozone presented as a single-peak curve, with the peak appearing at about 15:00-16:00. Diurnal variations in most ozone precursors showed bimodal curves; the first peak appeared at about 08:00-09:00, and the second peak appeared at night. Hourly concentrations of ozone on the weekend were higher than those on weekdays between 11:00 and 24:00 in urban Beijing, which was suggestive of a significant weekend effect. This may be because NO inhibition on the weekend is weaker than that on weekdays during the ozone formation phase. Diurnal variations in OX (NO2 + O3) showed a single peak, which appeared at 15:00 or 16:00. The results of correlation analysis among OX, O3, and NO2 suggested that OX was mainly controlled by O3 during the day and by NO2 during the night throughout the year. OX was controlled by NO2 during both the day and night during winter due to the low concentration of O3. The regional transport of ozone along the upwind direction was found in a typical ozone pollution event in summer in Beijing.

  8. Ozone modeling within plasmas for ozone sensor applications

    OpenAIRE

    Arshak, Khalil; Forde, Edward; Guiney, Ivor

    2007-01-01

    peer-reviewed Ozone (03) is potentially hazardous to human health and accurate prediction and measurement of this gas is essential in addressing its associated health risks. This paper presents theory to predict the levels of ozone concentration emittedfrom a dielectric barrier discharge (DBD) plasma for ozone sensing applications. This is done by postulating the kinetic model for ozone generation, with a DBD plasma at atmospheric pressure in air, in the form of a set of rate equations....

  9. Changes in fluorescence spectra of bioaerosols exposed to ozone in a laboratory reaction chamber to simulate atmospheric aging.

    Science.gov (United States)

    Santarpia, Joshua L; Pan, Yong-Le; Hill, Steven C; Baker, Neal; Cottrell, Brian; McKee, Laura; Ratnesar-Shumate, Shanna; Pinnick, Ronald G

    2012-12-31

    A laboratory system for exposing aerosol particles to ozone and rapidly measuring the subsequent changes in their single-particle fluorescence is reported. The system consists of a rotating drum chamber and a single-particle fluorescence spectrometer (SPFS) utilizing excitation at 263 nm. Measurements made with this system show preliminary results on the ultra-violet laser-induced-fluorescence (UV-LIF) spectra of single aerosolized particles of Yersinia rohdei, and of MS2 (bacteriophage) exposed to ozone. When bioparticles are exposed in the chamber the fluorescence emission peak around 330 nm: i) decreases in intensity relative to that of the 400-550 nm band; and ii) shifts slightly toward shorter-wavelengths (consistent with further drying of the particles). In these experiments, changes were observed at exposures below the US Environmental Protection Agency (EPA) limits for ozone.

  10. Kudzu ( Pueraria montana ) invasion doubles emissions of nitric oxide and increases ozone pollution

    National Research Council Canada - National Science Library

    Jonathan E. Hickman; Shiliang Wu; Loretta J. Mickley; Manuel T. Lerdau; Christopher B. Field

    2010-01-01

    The nitrogen-fixing legume kudzu (Pueraria montana) is a wide-spread invasive plant in the southeastern United States with physiological traits that may lead to important impacts on ecosystems and the atmosphere...

  11. The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

    Directory of Open Access Journals (Sweden)

    J. Zahardis

    2007-01-01

    Full Text Available The heterogeneous processing of organic aerosols by trace oxidants has many implications to atmospheric chemistry and climate regulation. This review covers a model heterogeneous reaction system (HRS: the oleic acid-ozone HRS and other reaction systems featuring fatty acids, and their derivatives. The analysis of the commonly observed aldehyde and organic acid products of ozonolysis (azelaic acid, nonanoic acid, 9-oxononanoic acid, nonanal is described. The relative product yields are noted and explained by the observation of secondary chemical reactions. The secondary reaction products arising from reactive Criegee intermediates are mainly peroxidic, notably secondary ozonides and α-acyloxyalkyl hydroperoxide oligomers and polymers, and their formation is in accord with solution and liquid-phase ozonolysis. These highly oxygenated products are of low volatility and hydrophilic which may enhance the ability of particles to act as cloud condensation nuclei (CCN. The kinetic description of this HRS is critically reviewed. Most kinetic studies suggest this oxidative processing is either a near surface reaction that is limited by the diffusion of ozone or a surface based reaction. Internally mixed particles and coatings represent the next stage in the progression towards more realistic proxies of tropospheric organic aerosols and a description of the products and the kinetics resulting from the ozonolysis of these proxies, which are based on fatty acids or their derivatives, is presented. Finally, the main atmospheric implications of oxidative processing of particulate containing fatty acids are presented. These implications include the extended lifetime of unsaturated species in the troposphere facilitated by the presence of solids, semi-solids or viscous phases, and an enhanced rate of ozone uptake by particulate unsaturates compared to corresponding gas-phase organics. Ozonolysis of oleic acid enhances its CCN activity, which implies that

  12. On the relationship between total ozone and atmospheric dynamics and chemistry at mid-latitudes – Part 2: The effects of the El Niño/Southern Oscillation, volcanic eruptions and contributions of atmospheric dynamics and chemistry to long-term total ozone changes

    Directory of Open Access Journals (Sweden)

    H. E. Rieder

    2013-01-01

    Full Text Available We present the first spatial analysis of "fingerprints" of the El Niño/Southern Oscillation (ENSO and atmospheric aerosol load after major volcanic eruptions (El Chichón and Mt. Pinatubo in extreme low and high (termed ELOs and EHOs, respectively and mean values of total ozone for the northern and southern mid-latitudes (defined as the region between 30° and 60° north and south, respectively. Significant influence on ozone extremes was found for the warm ENSO phase in both hemispheres during spring, especially towards low latitudes, indicating the enhanced ozone transport from the tropics to the extra-tropics. Further, the results confirm findings of recent work on the connection between the ENSO phase and the strength and extent of the southern ozone "collar". For the volcanic eruptions the analysis confirms findings of earlier studies for the northern mid-latitudes and gives new insights for the Southern Hemisphere. The results provide evidence that the negative effect of the eruption of El Chichón might be partly compensated by a strong warm ENSO phase in 1982–1983 at southern mid-latitudes. The strong west-east gradient in the coefficient estimates for the Mt. Pinatubo eruption and the analysis of the relationship between the AAO and ENSO phase, the extent and the position of the southern ozone "collar" and the polar vortex structure provide clear evidence for a dynamical "masking" of the volcanic signal at southern mid-latitudes. The paper also analyses the contribution of atmospheric dynamics and chemistry to long-term total ozone changes. Here, quite heterogeneous results have been found on spatial scales. In general the results show that EESC and the 11-yr solar cycle can be identified as major contributors to long-term ozone changes. However, a strong contribution of dynamical features (El Niño/Southern Oscillation (ENSO, North Atlantic Oscillation (NAO, Antarctic Oscillation (AAO, Quasi-Biennial Oscillation (QBO to ozone

  13. Recent increase of ethane detected in the remote atmosphere of the Northern Hemisphere

    Science.gov (United States)

    Franco, Bruno; Bader, Whitney; Bovy, Benoît; Mahieu, Emmanuel; Fischer, Emily V.; Strong, Kimberly; Conway, Stephanie; Hannigan, James W.; Nussbaumer, Eric; Bernath, Peter F.; Boone, Chris D.; Walker, Kaley A.

    2015-04-01

    Ethane (C2H6) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) - HOx - NOx chemistry responsible for generating and destroying tropospheric ozone. By acting as a major sink for tropospheric OH radicals, the abundance of C2H6 influences the atmospheric content of carbon monoxide and impacts the lifetime of methane. Moreover, it is an important source of PAN, a thermally unstable reservoir for NOx radicals. On a global scale, the main sources of C2H6 are leakage from the production, transport of natural gas loss, biofuel consumption and biomass burning, mainly located in the Northern Hemisphere. Due to its relatively long lifetime of approximately two months, C2H6 is a sensitive indicator of tropospheric pollution and transport. Using an optimized retrieval strategy (see Franco et al., 2014), we present here a 20-year long-term time series of C2H6 column abundance retrieved from ground-based Fourier Transform InfraRed (FTIR) solar spectra recorded from 1994 onwards at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 3580 m a.s.l.), part of the Network for the Detection of Atmospheric Composition Change (NDACC, see http://www.ndacc.org). After a regular 1994 - 2008 decrease of the C2H6 amounts, which is very consistent with prior major studies (e.g., Aydin et al., 2011; Simpson et al., 2012) and our understanding of global C2H6 emissions, trend analysis using a bootstrap resampling tool reveals a C2H6 upturn and a statistically-significant sharp burden increase from 2009 onwards (Franco et al., 2014). We hypothesize that this observed recent increase in C2H6 could affect the whole Northern Hemisphere and may be related to the recent massive growth in the exploitation of shale gas and tight oil reservoirs. This hypothesis is supported by measurements derived from solar occultation observations performed since 2004 by the Atmospheric Chemistry Experiment - Fourier

  14. Ozone layer - climate change interactions. Influence on UV levels and UV related effects

    NARCIS (Netherlands)

    Kelfkens G; Bregman A; de Gruijl FR; van der Leun JC; Piquet A; van Oijen T; Gieskes WWC; van Loveren H; Velders GJM; Martens P; Slaper H; NOP; LPI; LLO

    2002-01-01

    Ozone in the atmosphere serves as a partially protective filter against the most harmful part of the solar UV-spectrum. Decreases in ozone lead to increases in ambient UV with a wide variety of adverse effects on human health, aquatic and terrestrial ecosystems and food chains. Human health

  15. The Total Ozone Series of Arosa: History, Homogenization and new results using statistical extreme value theory

    Science.gov (United States)

    Staehelin, J.; Rieder, H. E.; Maeder, J. A.; Ribatet, M.; Davison, A. C.; Stübi, R.

    2009-04-01

    Atmospheric ozone protects the biota living at the Earth's surface from harmful solar UV-B and UV-C radiation. The global ozone shield is expected to gradually recover from the anthropogenic disturbance of ozone depleting substances (ODS) in the coming decades. The stratospheric ozone layer at extratropics might significantly increase above the thickness of the chemically undisturbed atmosphere which might enhance ozone concentrations at the tropopause altitude where ozone is an important greenhouse gas. At Arosa, a resort village in the Swiss Alps, total ozone measurements started in 1926 leading to the longest total ozone series of the world. One Fery spectrograph and seven Dobson spectrophotometers were operated at Arosa and the method used to homogenize the series will be presented. Due to its unique length the series allows studying total ozone in the chemically undisturbed as well as in the ODS loaded stratosphere. The series is particularly valuable to study natural variability in the period prior to 1970, when ODS started to affect stratospheric ozone. Concepts developed by extreme value statistics allow objective definitions of "ozone extreme high" and "ozone extreme low" values by fitting the (daily mean) time series using the Generalized Pareto Distribution (GPD). Extreme high ozone events can be attributed to effects of ElNino and/or NAO, whereas in the chemically disturbed stratosphere high frequencies of extreme low total ozone values simultaneously occur with periods of strong polar ozone depletion (identified by statistical modeling with Equivalent Stratospheric Chlorine times Volume of Stratospheric Polar Clouds) and volcanic eruptions (such as El Chichon and Pinatubo).

  16. Quantifying VOC-Reaction Tracers, Ozone Production, and Continuing Aerosol Production Rates in Urban and Far-Downwind Atmospheres

    Science.gov (United States)

    Chatfield, Robert; Ren, X.; Brune, W.; Fried, A.; Schwab, J.

    2008-01-01

    We have found a surprisingly informative decomposition of the complex question of smoggy ozone production (basically, [HO2] in a more locally determined field of [NO]) in the process of linked investigations of modestly smoggy Eastern North America (by NASA aircraft, July 2004) and rather polluted Flushing, NYC (Queens College, July, 2001). In both rural and very polluted situations, we find that a simple contour graph parameterization of the local principal ozone production rate can be estimated using only the variables [NO] and j(sub rads) [HCHO]: Po(O3) = c (j(sub rads) [HCHO])(sup a) [HCHO](sup b). Here j(sub rads) is the photolysis of HCHO to radicals, presumably capturing many harder-UV photolytic processes and the principle ozone production is that due to HO2; mechanisms suggest that ozone production due to RO2 is closely correlated, often suggesting a limited range of different proportionality factors. The method immediately suggests a local interpretation for concepts of VOC limitation and NOx limitation. We believe that the product j(sub rads) [HCHO] guages the oxidation rate of observed VOC mixtures in a way that also provides [HO2] useful for the principle ozone production rate k [HO2] [NO], and indeed, all ozone chemical production. The success of the method suggests that dominant urban primary-HCHO sources may transition to secondary plume-HCHO sources in a convenient way. Are there other, simple, near-terminal oxidized VOC's which help guage ozone production and aerosol particle formation? Regarding particles, we report on, to the extent NASA Research resources allow, on appealing relationships between far-downwind (Atlantic PBL) HCHO and very fine aerosol (including sulfate. Since j(sub rads) [HCHO] provides a time-scale, we may understand distant-plume particle production in a more quantitative manner. Additionally we report on a statistical search in the nearer field for relationships between glyoxals (important near-terminal aromatic and isoprene

  17. Quantification of relative contribution of Antarctic ozone depletion to increased austral extratropical precipitation during 1979-2013

    Science.gov (United States)

    Bai, Kaixu; Chang, Ni-Bin; Gao, Wei

    2016-02-01

    Attributing the observed climate changes to relevant forcing factors is critical to predicting future climate change scenarios. Precipitation observations in the Southern Hemisphere indicate an apparent moistening pattern over the extratropics during the time period 1979 to 2013. To investigate the predominant forcing factor in triggering such an observed wetting climate pattern, precipitation responses to four climatic forcing factors, including Antarctic ozone, water vapor, sea surface temperature (SST), and carbon dioxide, were assessed quantitatively in sequence through an inductive approach. Coupled time-space patterns between the observed austral extratropical precipitation and each climatic forcing factor were firstly diagnosed by using the maximum covariance analysis (MCA). With the derived time series from each coupled MCA modes, statistical relationships were established between extratropical precipitation variations and each climatic forcing factor by using the extreme learning machine. Based on these established statistical relationships, sensitivity tests were conducted to estimate precipitation responses to each climatic forcing factor quantitatively. Quantified differential contribution with respect to those climatic forcing factors may explain why the observed austral extratropical moistening pattern is primarily driven by the Antarctic ozone depletion, while mildly modulated by the cooling effect of equatorial Pacific SST and the increased greenhouse gases, respectively.

  18. Tracking the sources of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.; Churkina, G.; Coates, J.; Grote, R.; Mar, K.; von Schneidemesser, E.; Zhu, S.

    2013-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this set of studies we examine the attribution of tropospheric ozone to emissions of VOC using a tagging approach, whereby each VOC oxidation intermediate in model chemical mechanisms is tagged with the identity of its primary emitted compound, allowing modelled ozone production to be directly attributed to all emitted VOCs in the model. Using a global model we

  19. Impacts of stratospheric sulfate geoengineering on tropospheric ozone

    Science.gov (United States)

    Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

    2017-10-01

    A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion

  20. Impacts of stratospheric sulfate geoengineering on tropospheric ozone

    Directory of Open Access Journals (Sweden)

    L. Xia

    2017-10-01

    Full Text Available A range of solar radiation management (SRM techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air

  1. Simulation of climate changes during the 21. century including stratospheric ozone; Simulation des changements climatiques au cours du 21. siecle incluant l'ozone stratospherique

    Energy Technology Data Exchange (ETDEWEB)

    Royer, J.F.; Cariolle, D.; Chauvin, F.; Deque, M.; Douville, H.; Rong-Ming, Hu; Planton, S.; Rascol, A.; Ricard, J.L.; Salas Y Melia, D.; Sevault, F.; Simon, P.; Somot, S.; Tyteca, S. [Meteo-France, CNRM/GMGEC, 31 - Toulouse (France); Terray, L.; Valcke, S. [Cerfacs, 31 - Toulouse (France)

    2002-03-01

    Two climate simulations of 150 years, performed with a coupled ocean/sea-ice/atmosphere model including stratospheric ozone, respectively with and without heterogeneous chemistry, simulate the tropospheric warming associated with an increase of the greenhouse effect of carbon dioxide and other trace gases since 1950 and their impact on sea-ice extent, as well as the stratospheric cooling and its impact on ozone concentration. The scenario with heterogeneous chemistry reproduces the formation of the ozone hole over the South Pole from the 1970's and its deepening until the present time, and shows that the ozone hole should progressively fill during the coming decades. (authors)

  2. Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases

    Directory of Open Access Journals (Sweden)

    D. A. Plummer

    2010-09-01

    Full Text Available A state-of-the-art chemistry climate model coupled to a three-dimensional ocean model is used to produce three experiments, all seamlessly covering the period 1950–2100, forced by different combinations of long-lived Greenhouse Gases (GHGs and Ozone Depleting Substances (ODSs. The experiments are designed to quantify the separate effects of GHGs and ODSs on the evolution of ozone, as well as the extent to which these effects are independent of each other, by alternately holding one set of these two forcings constant in combination with a third experiment where both ODSs and GHGs vary. We estimate that up to the year 2000 the net decrease in the column amount of ozone above 20 hPa is approximately 75% of the decrease that can be attributed to ODSs due to the offsetting effects of cooling by increased CO2. Over the 21st century, as ODSs decrease, continued cooling from CO2 is projected to account for more than 50% of the projected increase in ozone above 20 hPa. Changes in ozone below 20 hPa show a redistribution of ozone from tropical to extra-tropical latitudes with an increase in the Brewer-Dobson circulation. In addition to a latitudinal redistribution of ozone, we find that the globally averaged column amount of ozone below 20 hPa decreases over the 21st century, which significantly mitigates the effect of upper stratospheric cooling on total column ozone. Analysis by linear regression shows that the recovery of ozone from the effects of ODSs generally follows the decline in reactive chlorine and bromine levels, with the exception of the lower polar stratosphere where recovery of ozone in the second half of the 21st century is slower than would be indicated by the decline in reactive chlorine and bromine concentrations. These results also reveal the degree to which GHG-related effects mute the chemical effects of N2O on ozone in the standard future scenario used for the WMO Ozone Assessment. Increases in the

  3. Observations of atmospheric ozone - 38 to 76 deg north latitude at altitudes from 8 km to the surface

    Science.gov (United States)

    Gregory, G. L.; Beck, S. M.; Hudgins, C. H.

    1984-01-01

    Ozone data were obtained from 8 km to the surface and at latitudes from 38 to 76 deg N during January and February 1983. Flight lines covered northeastern U.S., Canada, and Greenland. The results of the latitudinal survey at 5- to 8-km altitude showed O3 mixing ratios to be about 40 ppbv with little variation in latitude. One region of elevated O3 was observed and extended from 54 N to 57 deg N latitude. Ozone reached 150 ppbv at 6.4-km altitude. This sampling was stratospheric air as the tropopause height was 5.6-km altitude. Profiles at 76, 67, and 53 deg N showed O3 to be be well mixed from about 5 km to the surface. In some cases, profiles identified a layer of 1 km to 100 m vertical dimension at the surface, in which O3 destruction had occurred.

  4. Effects of an ozone-generating air purifier on indoor secondary particles in three residential dwellings.

    Science.gov (United States)

    Hubbard, H F; Coleman, B K; Sarwar, G; Corsi, R L

    2005-12-01

    The use of indoor ozone generators as air purifiers has steadily increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve health. In addition to the harmful effects of ozone, recent studies have shown that heterogeneous and homogeneous reactions between ozone and some unsaturated hydrocarbons can be an important source of indoor secondary pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles. Experiments were conducted in one apartment and two detached single-family dwellings in Austin, TX, to assess the effects of an ozone generator on indoor secondary organic aerosol concentrations in actual residential settings. Ozone was generated using a commercial ozone generator marketed as an air purifier, and particle measurements were recorded before, during, and after the release of terpenes from a pine oil-based cleaning product. Particle number concentration, ozone concentration, and air exchange rate were measured during each experiment. Particle number and mass concentrations increased when both terpenes and ozone were present at elevated levels. Experimental results indicate that ozone generators in the presence of terpene sources facilitate the growth of indoor fine particles in residential indoor atmospheres. Human exposure to secondary organic particles can be reduced by minimizing the intentional release of ozone, particularly in the presence of terpene sources. Past studies have shown that ozone-initiated indoor chemistry can lead to elevated concentrations of fine particulate matter, but have generally been completed in controlled laboratory environments and office buildings. We explored the effects of an explicit ozone generator marketed as an air purifier on the formation of secondary organic aerosol mass in actual residential indoor settings. Results indicate significant increases in number and mass concentrations for particles

  5. Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe

    NARCIS (Netherlands)

    Bragazza, L.; Tahvanainen, T.; Kutnar, L.; Rydin, H.; Limpens, J.; Hajek, M.; Grosvernier, P.; Hansen, I.; Lacumin, P.; Gerdol, R.

    2004-01-01

    We studied the effects of increasing levels of atmospheric nitrogen (N) deposition on nutrient limitation of ombrotrophic Sphagnum plants. • Fifteen mires in 11 European countries were selected across a natural gradient of bulk atmospheric N deposition from 0.1 to 2 g/m2 year-1. Nutritional

  6. The sensitivity of polar ozone depletion to proposed geoengineering schemes.

    Science.gov (United States)

    Tilmes, Simone; Müller, Rolf; Salawitch, Ross

    2008-05-30

    The large burden of sulfate aerosols injected into the stratosphere by the eruption of Mount Pinatubo in 1991 cooled Earth and enhanced the destruction of polar ozone in the subsequent few years. The continuous injection of sulfur into the stratosphere has been suggested as a "geoengineering" scheme to counteract global warming. We use an empirical relationship between ozone depletion and chlorine activation to estimate how this approach might influence polar ozone. An injection of sulfur large enough to compensate for surface warming caused by the doubling of atmospheric CO2 would strongly increase the extent of Arctic ozone depletion during the present century for cold winters and would cause a considerable delay, between 30 and 70 years, in the expected recovery of the Antarctic ozone hole.

  7. What would have happened to the ozone layer if chlorofluorocarbons (CFCs had not been regulated?

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2009-03-01

    Full Text Available Ozone depletion by chlorofluorocarbons (CFCs was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs has been firmly established with laboratory measurements, atmospheric observations, and modeling studies. This science research led to the implementation of international agreements that largely stopped the production of ODSs. In this study we use a fully-coupled radiation-chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally-averaged column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole. The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet radiation increases, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.

  8. Climate-chemistry interaction affecting tropospheric ozone

    Science.gov (United States)

    Mao, Huiting

    1999-09-01

    Tropospheric ozone, an important radiative-chemical species, has been observed increasing especially at northern midlatitudes during the past few decades. This dissertation addresses climate-chemistry interaction associated with such increases in three aspects using observations as well as atmospheric chemistry and climate models. Ozone impact on climate is first evaluated by radiative forcing calculations due to observed ozone changes. It is found that a 10% increase in tropospheric ozone causes a radiative forcing of 0.17 Wm-2 using a fixed temperature (FT) method or 0.13 Wm-2 using a fixed dynamic heating (FDH) method, which is comparable to the radiative forcing 0.26 (FT) and -0.09 Wm-2 (FDH) caused by the stratospheric ozone depletion during the 1980s. Second, radiative forcing due to changes in ozone precursors is estimated. Ozone changes in response to a 20% reduction in surface NOx emission in six regions around the globe differ between regions. A maximum decrease in ozone column reaches 5% in southeast Asia and the central Atlantic Ocean, inducing a local radiative forcing of up to -0.1 Wm-2 in those regions. It indicates that surface NOx emission changes can potentially affect regional climate. Third, the effects of climate and climate changes on atmospheric chemistry are addressed with two studies. One study investigates the effects of global warming on methane and ozone, and another looks into cloud effects on photodissociation rate constants. Calculations based on the IPCC business-as-usual scenario indicate that by 2050, temperature and moisture increases can suppress methane and tropospheric ozone increases by 17% and 11%, respectively, in reference to the 1990 concentrations. The combined effects offset the global warming induced forcing 3.90 Wm -2 by -0.46 Wm-2. A one-dimensional study suggests that a typical cirrus cloud (τ = 2) can significantly increase J(O1D) and J(NO2) around the tropopause with a maximum of 21%. Geographical and seasonal

  9. Use of AIRS, OMI, MLS, and TES Data in Assessing Forest Ecosystem Exposure to Ozone

    Science.gov (United States)

    Spruce, Joseph P.

    2007-01-01

    Ground-level ozone at high levels poses health threats to exposed flora and fauna, including negative impacts to human health. While concern is common regarding depletion of ozone in the stratosphere, portions of the urban and rural United States periodically have high ambient levels of tropospheric ozone on the ground. Ozone pollution can cause a variety of impacts to susceptible vegetation (e.g., Ponderosa and Jeffrey pine species in the southwestern United States), such as stunted growth, alteration of growth form, needle or leaf chlorosis, and impaired ability to withstand drought-induced water stress. In addition, Southern Californian forests with high ozone exposures have been recently subject to multiyear droughts that have led to extensive forest overstory mortality from insect outbreaks and increased incidence of wildfires. Residual forests in these impacted areas may be more vulnerable to high ozone exposures and to other forest threats than ever before. NASA sensors collect a wealth of atmospheric data that have been used recently for mapping and monitoring regional tropospheric ozone levels. AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), MLS (Microwave Limb Sounder), and TES (Tropospheric Emission Spectrometer) data could be used to assess forest ecosystem exposure to ozone. Such NASA data hold promise for providing better or at least complementary synoptic information on ground-level ozone levels that Federal agency partners can use to assess forest health trends and to mitigate the threats as needed in compliance with Federal laws and mandates. NASA data products on ozone concentrations may be able to aid applications of DSTs (decision support tools) adopted by the USDA FS (U.S. Department of Agriculture Forest Service) and by the NPS (National Park Service), such as the Ozone Calculator, in which ground ozone estimates are employed to assess ozone impacts to forested vegetation.

  10. Exposure of Norway spruce to ozone increases the sensitivity of current year needles to photoinhibition and desiccation

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    1994-01-01

    decreases in net photosynthesis and chlorophyll fluorescence (FN/FM) were found during periods with co-occurrence of high ozone concentrations And high light intensities, indicating interactions between effects of ozone and photoinhibition. After termination of fumigation enhanced rates of photosynthesis...

  11. Possibility to sound the atmospheric ozone by a radiosonde equipped with two temperature sensors, sensitive and non-sensitive to the long wave radiation

    Science.gov (United States)

    Kitaoka, T.; Sumi, T.

    1994-01-01

    The sensitiveness of white coated thermistor sensors and non-sensitiveness of the gold coated over white thermistor sensors (which have been manufactured by a vacuum evaporation process) to long wave radiation were ascertained by some simple experiments in-room and also by analyses of some results of experimental soundings. From results of analyses on the temperature discrepancies caused by long wave radiation, the possibility to sound the atmospheric ozone partial pressure by a radiosonde equipped with two kinds of sensors, sensitive and non-sensitive to the long wave radiation was suggested, and the test results of the newly developed software for the deduction of ozone partial pressure in upper layers was also shown. However, it was found that the following is the necessary condition to realize the purpose. The sounding should be made by a radiosonde equipped with three sensors, instead of two, one being non-sensitive to the long wave radiation perfectly, and the other two also non-sensitive partially to the downward one, with two different angles of exposure upward. It is essential for the realization of the purpose to get two different values of temperature discrepancies simultaneously observed by the three sensors mentioned above and to avoid the troublesome effects of the upward long wave radiation.

  12. Decadal evolution of the Antarctic ozone hole

    Science.gov (United States)

    Jiang, Y.; Yung, Y. L.; Zurek, R. W.

    1996-01-01

    Ozone column amounts obtained by the total ozone mapping spectrometer (TOMS) in the southern polar region are analyzed during late austral winter and spring (days 240-300) for 1980-1991 using area-mapping techniques and area-weighted vortex averages. The vortex here is defined using the -50 PVU (1 PVU = 1.0 x 10(-6) K kg-1 m2 s-1) contour on the 500 K isentropic surface. The principal results are: (1) there is a distinct change after 1985 in the vortex-averaged column ozone depletion rate during September and October, the period of maximum ozone loss, and (2) the vortex-averaged column ozone in late August (day 240) has dropped by 70 Dobson units (DU) in a decade due to the loss in the dark and the dilution effect. The mean ozone depletion rate in the vortex between day 240 and the day of minimum vortex-averaged ozone is about 1 DU d-1 at the beginning of the decade, increasing to about 1.8 DU d-1 by 1985, and then apparently saturating thereafter. The vortex-average column ozone during September and October has declined at the rate of 11.3 DU yr-1 (3.8%) from 1980 to 1987 (90 DU over 8 years) and at a smaller rate of 2 DU yr-1 (0.9%) from 1987 to 1991 (10 DU over 5 years, excluding the anomalous year 1988). We interpret the year-to-year trend in the ozone depletion rate during the earlier part of the decade as due to the rise of anthropogenic chlorine in the atmosphere. The slower trend at the end of the decade indicates saturation of ozone depletion in the vortex interior, in that chlorine amounts in the mid-1980s were already sufficiently high to deplete most of the ozone in air within the isolated regions of the lower-stratospheric polar vortex. In subsequent years, increases in stratospheric chlorine may have enhanced wintertime chemical loss of ozone in the south polar vortex even before major losses during the Antarctic spring.

  13. Comparative study of ozonized olive oil and ozonized sunflower oil

    Directory of Open Access Journals (Sweden)

    Díaz Maritza F.

    2006-01-01

    Full Text Available In this study the ozonized olive and sunflower oils are chemical and microbiologically compared. These oils were introduced into a reactor with bubbling ozone gas in a water bath at room temperature until they were solidified. The peroxide, acidity and iodine values along with antimicrobial activity were determined. Ozonization effects on the fatty acid composition of these oils were analyzed using Gas-Liquid Chromatographic Technique. An increase in peroxidation and acidity values was observed in both oils but they were higher in ozonized sunflower oil. Iodine value was zero in ozonized olive oil whereas in ozonized sunflower was 8.8 g Iodine per 100 g. The antimicrobial activity was similar for both ozonized oils except for Minimum Bactericidal Concentrations of Pseudomona aeruginosa. Composition of fatty acids in both ozonized oils showed gradual decrease in unsaturated fatty acids (C18:1, C18:2 with gradual increase in ozone doses.

  14. Global Health Benefits from Reductions in Background Tropospheric Ozone due to Methane Emission Controls

    Science.gov (United States)

    West, J. J.; Mauzerall, D. L.; Fiore, A. M.; Horowitz, L. W.

    2005-05-01

    Increases in background ozone throughout the troposphere are partially attributed to rising anthropogenic methane concentrations, which are projected to continue to increase in the future. Because methane is long-lived and affects background ozone, controls on methane emissions would reduce surface ozone concentrations fairly uniformly around the globe. Epidemiological research indicates that exposure to ozone increases incidence of respiratory ailments and premature mortality. In addition, exposure to ozone reduces agricultural yields and damages natural ecosystems. We use the MOZART-2 global atmospheric chemistry and transport model to estimate the effects on global surface ozone of perturbations in methane emissions. We consider a baseline scenario for 2000 and the 2030 A2 scenario (emissions from the IPCC AR-4 2030 atmospheric chemistry experiments), and examine the impact on ozone of decreasing anthropogenic methane emissions relative to this baseline by 20%. Using the simulated spatially-distributed decreases in surface ozone concentrations resulting from these reductions in methane emissions, we estimate the global benefits to human health in the methane emission reduction scenario. We focus on human mortality, and consider the sensitivity of our estimates to different assumptions of health effect thresholds at low ozone concentrations.

  15. What Would Have Happened to the Ozone Layer if Chlorofluorocarbons (CFCs) had not been Regulated?

    Science.gov (United States)

    Newman, Paul A.; Oman, L. D.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M. M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.; hide

    2008-01-01

    Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the sci entific connection between ozone losses and CFCs and other ozone depl eting substances (ODSs) has been firmly established with laboratory m easurements, atmospheric observations, and modeling research. This science research led to the implementation of international agreements t hat largely stopped the production of ODSs. In this study we use a fu lly-coupled radiation-chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an ann ual rate of 3%. In this "world avoided" simulation 1.7 % of the globa lly-average column ozone is destroyed by 2020, and 67% is destroyed b y 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observ ed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower strat osphere remain constant until about 2053 and then collapse to near ze ro by 2058 as a result of heterogeneous chemical processes (as curren tly observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet radiation increa ses, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.

  16. Atmospheric Ozone And Its Biosphere - Atmosphere Exchange In A Mangrove Forest Ecosystem A Case Study From Sundarbans NE Coast Of India

    Directory of Open Access Journals (Sweden)

    Manab Kumar Dutta

    2015-01-01

    Full Text Available ABSTRACT Temporal variation of atmospheric O3 and its biosphere atmosphere exchange were monitored in the Sundarbans mangrove forest from January 2011 to December 2011 on bimonthly basis. O3 mixing ratios at 10 m and 20 m heights over the forest atmosphere ranged between 14.66 1.88 to 37.90 0.91 and 19.32 6.27 to 39.80 10.13 ppbv respectively having maximal premonsoon and minimal monsoon periods. Average daytime O3 mixing ratio was 1.69 times higher than nighttime indicates significant photo chemical production of O3 in forest atmosphere. Annual averaged O3 mixing ratio in 10 m height was 13.2 lower than 20 m height induces exchange of O3 across mangrove biosphere atmosphere interface depending upon micrometeorological conditions of the forest ecosystem. Annual average biosphere atmosphere O3 exchange flux in this mangrove forest environment was 0.441 g m-2 s-1. Extrapolating the value for entire forest surface area the mangrove ecosystem acts as a sink of 58.4GgO3 annually indicating significant contribution of Sundarbans mangroves towards regional atmospheric O3 budget as well as climate change.

  17. Changes in tropospheric composition and air quality due to stratospheric ozone depletion.

    Science.gov (United States)

    Solomon, Keith R; Tang, Xiaoyan; Wilson, Stephen R; Zanis, Prodromos; Bais, Alkiviadis F

    2003-01-01

    Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing air pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone due to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2), the emission of volatile organic compounds and the abundance of water vapor, are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone concentration can have a significant impact on human health and the environment. Trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) are produced by the atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). TFA has been measured in rain, rivers, lakes, and oceans, the ultimate sink for these and related compounds. Significant anthropogenic sources of TFA other than degradation HCFCs and HFCs have been identified. Toxicity tests under field conditions indicate that the concentrations of TFA and CDFA currently produced by the atmospheric degradation of HFCs and HCFCs do not present a risk to human health and the environment. The impact of the interaction between ozone depletion and future climate change is complex and a significant area of current research. For air quality and tropospheric composition, a range of physical parameters such as temperature, cloudiness and atmospheric transport will modify the impact of UV-B. Changes in the

  18. Measurement of Ozone Production Sensor

    Directory of Open Access Journals (Sweden)

    M. Cazorla

    2010-05-01

    Full Text Available A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS, measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

  19. Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects.

    Science.gov (United States)

    Wang, Tao; Xue, Likun; Brimblecombe, Peter; Lam, Yun Fat; Li, Li; Zhang, Li

    2017-01-01

    High concentrations of ozone in urban and industrial regions worldwide have long been a major air quality issue. With the rapid increase in fossil fuel consumption in China over the past three decades, the emission of chemical precursors to ozone-nitrogen oxides and volatile organic compounds-has increased sharply, surpassing that of North America and Europe and raising concerns about worsening ozone pollution in China. Historically, research and control have prioritized acid rain, particulate matter, and more recently fine particulate matter (PM2.5). In contrast, less is known about ozone pollution, partly due to a lack of monitoring of atmospheric ozone and its precursors until recently. This review summarizes the main findings from published papers on the characteristics and sources and processes of ozone and ozone precursors in the boundary layer of urban and rural areas of China, including concentration levels, seasonal variation, meteorology conducive to photochemistry and pollution transport, key production and loss processes, ozone dependence on nitrogen oxides and volatile organic compounds, and the effects of ozone on crops and human health. Ozone concentrations exceeding the ambient air quality standard by 100-200% have been observed in China's major urban centers such as Jing-Jin-Ji, the Yangtze River delta, and the Pearl River delta, and limited studies suggest harmful effect of ozone on human health and agricultural corps; key chemical precursors and meteorological conditions conductive to ozone pollution have been investigated, and inter-city/region transport of ozone is significant. Several recommendations are given for future research and policy development on ground-level ozone. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Total ozone decrease in the Arctic after REP events

    Directory of Open Access Journals (Sweden)

    V. C. Roldugin

    Full Text Available Eight periods of relativistic electron precipitation (REP with electron energies of more than 300 keV are identified from VLF data (10-14 kHz monitored along the Aldra (Norway - Apatity (Kola peninsula radio trace. In these cases, anomalous ionization below 55-50 km occurred without disturbing the higher layers of the ionosphere. The daily total ozone values in Murmansk for six days before and six days after the REP events are compared. In seven of eight events a decrease in the total ozone of about 20 DU is observed. In one event of 25 March, 1986, the mean total ozone value for six days before the REP is bigger than that for six days after, but this a case of an extremely high ozone increase (144 DU during the six days. However, on days 3 and 4 there was a minimum of about 47 DU with regard to REP days, so this case also confirms the concept of the ozone decrease after REP. The difference between mean ozone values for periods six days before and six days after the REPs was found also for 23 points in Arctic on TOMS data. The difference was negative only in Murmansk longitudinal sector. Along the meridian of the trace it was negative at high latitudes in both hemispheres and was near zero at low latitudes.

    Key words: Atmospheric composition and structure (middle atmosphere - composition and chemistry - Meteorology and atmospheric dynamics (polar meteorology

  1. Total ozone decrease in the Arctic after REP events

    Directory of Open Access Journals (Sweden)

    V. C. Roldugin

    2000-03-01

    Full Text Available Eight periods of relativistic electron precipitation (REP with electron energies of more than 300 keV are identified from VLF data (10-14 kHz monitored along the Aldra (Norway - Apatity (Kola peninsula radio trace. In these cases, anomalous ionization below 55-50 km occurred without disturbing the higher layers of the ionosphere. The daily total ozone values in Murmansk for six days before and six days after the REP events are compared. In seven of eight events a decrease in the total ozone of about 20 DU is observed. In one event of 25 March, 1986, the mean total ozone value for six days before the REP is bigger than that for six days after, but this a case of an extremely high ozone increase (144 DU during the six days. However, on days 3 and 4 there was a minimum of about 47 DU with regard to REP days, so this case also confirms the concept of the ozone decrease after REP. The difference between mean ozone values for periods six days before and six days after the REPs was found also for 23 points in Arctic on TOMS data. The difference was negative only in Murmansk longitudinal sector. Along the meridian of the trace it was negative at high latitudes in both hemispheres and was near zero at low latitudes.Key words: Atmospheric composition and structure (middle atmosphere - composition and chemistry - Meteorology and atmospheric dynamics (polar meteorology

  2. Effects of shrub and tree cover increase on the near-surface atmosphere in northern Fennoscandia

    Directory of Open Access Journals (Sweden)

    J. H. Rydsaa

    2017-09-01

    Full Text Available Increased shrub and tree cover in high latitudes is a widely observed response to climate change that can lead to positive feedbacks to the regional climate. In this study we evaluate the sensitivity of the near-surface atmosphere to a potential increase in shrub and tree cover in the northern Fennoscandia region. We have applied the Weather Research and Forecasting (WRF model with the Noah-UA land surface module in evaluating biophysical effects of increased shrub cover on the near-surface atmosphere at a fine resolution (5.4 km  ×  5.4 km. Perturbation experiments are performed in which we prescribe a gradual increase in taller vegetation in the alpine shrub and tree cover according to empirically established bioclimatic zones within the study region. We focus on the spring and summer atmospheric response. To evaluate the sensitivity of the atmospheric response to inter-annual variability in climate, simulations were conducted for two contrasting years, one warm and one cold. We find that shrub and tree cover increase leads to a general increase in near-surface temperatures, with the highest influence seen during the snowmelt season and a more moderate effect during summer. We find that the warming effect is stronger in taller vegetation types, with more complex canopies leading to decreases in the surface albedo. Counteracting effects include increased evapotranspiration, which can lead to increased cloud cover, precipitation, and snow cover. We find that the strength of the atmospheric feedback is sensitive to snow cover variations and to a lesser extent to summer temperatures. Our results show that the positive feedback to high-latitude warming induced by increased shrub and tree cover is a robust feature across inter-annual differences in meteorological conditions and will likely play an important role in land–atmosphere feedback processes in the future.

  3. Effects of shrub and tree cover increase on the near-surface atmosphere in northern Fennoscandia

    Science.gov (United States)

    Rydsaa, Johanne H.; Stordal, Frode; Bryn, Anders; Tallaksen, Lena M.

    2017-09-01

    Increased shrub and tree cover in high latitudes is a widely observed response to climate change that can lead to positive feedbacks to the regional climate. In this study we evaluate the sensitivity of the near-surface atmosphere to a potential increase in shrub and tree cover in the northern Fennoscandia region. We have applied the Weather Research and Forecasting (WRF) model with the Noah-UA land surface module in evaluating biophysical effects of increased shrub cover on the near-surface atmosphere at a fine resolution (5.4 km × 5.4 km). Perturbation experiments are performed in which we prescribe a gradual increase in taller vegetation in the alpine shrub and tree cover according to empirically established bioclimatic zones within the study region. We focus on the spring and summer atmospheric response. To evaluate the sensitivity of the atmospheric response to inter-annual variability in climate, simulations were conducted for two contrasting years, one warm and one cold. We find that shrub and tree cover increase leads to a general increase in near-surface temperatures, with the highest influence seen during the snowmelt season and a more moderate effect during summer. We find that the warming effect is stronger in taller vegetation types, with more complex canopies leading to decreases in the surface albedo. Counteracting effects include increased evapotranspiration, which can lead to increased cloud cover, precipitation, and snow cover. We find that the strength of the atmospheric feedback is sensitive to snow cover variations and to a lesser extent to summer temperatures. Our results show that the positive feedback to high-latitude warming induced by increased shrub and tree cover is a robust feature across inter-annual differences in meteorological conditions and will likely play an important role in land-atmosphere feedback processes in the future.

  4. Atmospheric lifetimes and ozone depletion potentials of methyl bromide (CH3Br) and dibromomethane (CH2Br2)

    Energy Technology Data Exchange (ETDEWEB)

    Mellouki, A.; Talukdar, R.K.; Schmoltner, A.; Gierczak, T.; Mills, M.J.; Solomon, S.; Ravishankara, A.R. (NOAA, Boulder, CO (United States))

    1992-10-01

    The rate coefficients for the reactions of OH radical with CH3Br and CH2Br2 were measured as functions of temperature using the laser photolysis - laser induced fluorescence method. This data was incorporated into a semiempirical model (Solomon et al., 1992) and a 2D model to calculate the steady-state ozone depletion potentials (ODP) and atmospheri lifetimes, tau, with greatly improved accuracy as compared to earlier studies. The calculated ODPs and tau are 0.65 and 1.7 years and 0.17 and 0.41 years for CH3Br and CH2Br2, respectively, using the semiempirical model. These lifetimes agree well with those calculated using a 2D model. This study better quantifies the ODPs and tau of these species which are needed inputs for discussion of possible regulation of human emissions currently under international considerations. 29 refs.

  5. Relationship between acceleration of hydroxyl radical initiation and increase of multiple-ultrasonic field amount in the process of ultrasound catalytic ozonation for degradation of nitrobenzene in aqueous solution.

    Science.gov (United States)

    Zhao, Lei; Ma, Weichao; Ma, Jun; Wen, Gang; Liu, Qianliang

    2015-01-01

    The synergetic effect between ozone and ultrasound can enhance the degradation of nitrobenzene and removal efficiency of TOC in aqueous solution, and the degradation of nitrobenzene follows the mechanism of hydroxyl radical (OH) oxidation. Under the same total ultrasonic power input condition, the degradation rate of nitrobenzene (kNB), the volumetric mass transfer coefficient of ozone (kLa), and the initiation rate of OH (kOH) increases with introduction of additional ultrasonic field (1-4) in the process of ozone/ultrasound. The increasing amount of ultrasonic fields accelerates the decomposition of ozone, leading to the rapid appearance of the maximum equilibrium value and the decrease in the accumulation concentration of ozone in aqueous solution with the increasing reaction time. The increase in mass transfer of gaseous ozone dissolved into aqueous solution and the acceleration in the decomposition of ozone in aqueous solution synchronously contribute to the increase of kLa. The investigation of mechanism confirms that the increasing amount of ultrasonic fields yields the increase in cavitation activity that improves the mass transfer and decomposition of ozone, resulting in acceleration of OH initiation, which determines the degradation of nitrobenzene in aqueous solution. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Increasing atmospheric humidity and CO2 concentration alleviate forest hydraulic failure risk

    Science.gov (United States)

    Liu, Y.; Parolari, A.; Kumar, M.; Porporato, A. M.; Katul, G. G.

    2016-12-01

    Climate-induced forest mortality is being observed throughout the globe and has the potential to alter ecosystem services provided by forests. Recent studies suggest that forest mortality is expected to be exacerbated under climate change due to intensified water and heat stress. While few dispute the claim that the compound effect of reduced soil water and increased heat stress increases the probability of forest mortality, impacts of other aspects of climate change have not been explored. Specifically, the impacts of concurrent changes in atmospheric humidity and atmospheric CO2 concentration, which may influence stomatal kinetics in ways that allow plants to operate despite reduced plant hydraulic capacity, remain unaddressed. Here, the risk of hydraulic failure (HFR), one of the key factors contributing to forest mortality is investigated by setting up a dynamic soil-plant-atmospheric model. The coupled and isolated responses of HFR to changes in precipitation amount and seasonality, air temperature, atmospheric humidity, and atmospheric CO2 concentration are analyzed. By incorporating CMIP5 climate projections, the synthetic future responses of HFR for 13 forest biomes across the globe are examined. The results indicate that while HFR is predicted to increase under shifting precipitation patterns and elevated air temperature, the increasing risks may be partly compensated by increases in atmospheric humidity and CO2 concentration. The alleviating effects are likely to be more significant for broadleaf forests than those for needleleaf forests. Our findings suggest that contributions of atmospheric humidity and CO2 concentration on HFR, independently of other effects such as seed production, germination, spread, disease outbreak, and resource competition at the community level, may lead to lower risks of forest mortality than previously thought.

  7. Atmospheric nitric oxide and ozone at the WAIS Divide deep coring site: a discussion of local sources and transport in West Antarctica

    Directory of Open Access Journals (Sweden)

    S. Masclin

    2013-09-01

    Full Text Available The first measurements of atmospheric nitric oxide (NO along with observations of ozone (O3, hydroperoxides (H2O2 and MHP and snow nitrate (NO3– on the West Antarctic Ice Sheet (WAIS were carried out at the WAIS Divide deep ice-coring site between 10 December 2008 and 11 January 2009. Average ±1σ mixing ratios of NO were 19 ± 31 pptv and confirmed prior model estimates for the summer boundary layer above WAIS. Mean ±1σ mixing ratios of O3 of 14 ± 4 ppbv were in the range of previous measurements from overland traverses across WAIS during summer, while average ±1σ concentrations of H2O2 and MHP revealed higher levels with mixing ratios of 743 ± 362 and 519 ± 238 pptv, respectively. An upper limit for daily average NO2 and NO emission fluxes from snow of 8.6 × 108 and 33.9 × 108 molecule cm–2 s–1, respectively, were estimated based on photolysis of measured NO3– and nitrite (NO2– in the surface snowpack. The resulting high NOx emission flux may explain the little preservation of NO3– in snow (~ 30% when compared to Summit, Greenland (75–93%. Assuming rapid and complete mixing into the overlying atmosphere, and steady state of NOx, these snow emissions are equivalent to an average (range production of atmospheric NOx of 30 (21–566 pptv h–1 for a typical atmospheric boundary-layer depth of 250 (354–13 m. These upper bounds indicate that local emissions from the snowpack are a significant source of short-lived nitrogen oxides above the inner WAIS. The net O3 production of 0.8 ppbv day–1 triggered with NO higher than 2 pptv is too small to explain the observed O3 variability. Thus, the origins of the air masses reaching WAIS Divide during this campaign were investigated with a 4-day back-trajectory analysis every 4 h. The resulting 168 back trajectories revealed that in 75% of all runs air originated from the Antarctic coastal slopes (58% and the inner WAIS (17%. For these air sources O3 levels were on average 13 ± 3

  8. Ozone studies in the Paso del Norte region

    Science.gov (United States)

    Becerra-Davila, Fernando

    obtained from this photolysis study demonstrate that the local ground level ozone formation is not only influenced by the strong solar radiation and changing aerosol makeup, but also by other heterogeneous factors and reactions. In addition, this research provided good evidence that the ground level ozone precursor regime in El Paso during the ozone episode of June 2006 was mostly VOC-limited. Much of this estimation was derived from measurements of local ambient VOC/NOx ratios. This finding shows that at least during June 2006, the non-linear surface ozone production increased during weekends compared to workdays in a habitually VOC-limited regime. The seasonal variations of columnar ozone as measured by a Multi-filter Rotating Shadowband instrument installed at the UTEP campus are analyzed for the first time for this region and results are presented. This investigation has addressed the problem of ground-level ozone formation in the Paso del Norte region. Urban ozone is a complex problem with many aspects that are not fully understood. In this investigation, a range of techniques has been used to address the study of local surface ozone episodes with the purpose of acquiring new insights and knowledge that will help understand and remediate the diverse atmospheric pollution events that affect this bi-national region recurrently. Innovative techniques were developed and used, ranging from the use of local ambient atmospheric pollution data to the utilization of complex modeling techniques to achieve the best possible computer results. Finally, the influence of ground level ozone concentrations in admissions to hospitals for this region due to respiratory diseases is analyzed. The comprehensive results obtained in this work will help to better understand ozone formation in the Paso del Norte Region for future policy regulation implementations.

  9. Beginning of the ozone recovery over Europe? − Analysis of the total ozone data from the ground-based observations, 1964−2004

    Directory of Open Access Journals (Sweden)

    B. Rajewska-Więch

    2005-07-01

    Full Text Available The total ozone variations over Europe (~50° N in the period 1964–2004 are analyzed for detection of signals of ozone recovery. The ozone deviations from the long-term monthly means (1964–1980 for selected European stations, where the ozone observations (by the Dobson spectrophotometers have been carried out continuously for at least 3–4 decades, are averaged and examined by a regression model. A new method is proposed to disclose both the ozone trend variations and date of the trend turnaround. The regression model contains a piecewise linear trend component and the terms describing the ozone response to forcing by "natural" changes in the atmosphere. Standard proxies for the dynamically driven ozone variations are used. The Multivariate Adaptive Regression Splines (MARS methodology and principal component analysis are used to find an optimal set of the explanatory variables and the trend pattern. The turnaround of the ozone trend in 1994 is suggested from the pattern of the piecewise linear trend component. Thus, the changes in the ozone mean level are calculated over the periods 1970–1994 and 1994–2003, for both the original time series and the time series having "natural" variations removed. Statistical significance of the changes are derived by bootstrapping. A first stage of recovery (according to the definition of the International Ozone Commission, i.e. lessening of a negative trend, is found over Europe. It seems possible that the increase in the ozone mean level since 1994 of about 1–2% is due to superposition of the "natural" processes. Comparison of the total ozone ground-based network (the Dobson and Brewer spectrophotometers and the satellite (TOMS, version 8 data over Europe shows the small bias in the mean values for the period 1996–2004, but the differences between the daily ozone values from these instruments are not trendless, and this may hamper an identification of the next stage of the ozone recovery over

  10. Ozonated olive oils and the troubles

    Science.gov (United States)

    Uysal, Bulent

    2014-01-01

    One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users. PMID:26401346

  11. Ozonated olive oils and the troubles.

    Science.gov (United States)

    Uysal, Bulent

    2014-01-01

    One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users.

  12. Land–atmosphere feedbacks amplify aridity increase over land under global warming

    Science.gov (United States)

    Berg, Alexis; Findell, Kirsten; Lintner, Benjamin; Giannini, Alessandra; Seneviratne, Sonia I.; van den Hurk, Bart; Lorenz, Ruth; Pitman, Andy; Hagemann, Stefan; Meier, Arndt; Cheruy, Frédérique; Ducharne, Agnès; Malyshev, Sergey; Milly, Paul C.

    2016-01-01

    The response of the terrestrial water cycle to global warming is central to issues including water resources, agriculture and ecosystem health. Recent studies indicate that aridity, defined in terms of atmospheric supply (precipitation, P) and demand (potential evapotranspiration, Ep) of water at the land surface, will increase globally in a warmer world. Recently proposed mechanisms for this response emphasize the driving role of oceanic warming and associated atmospheric processes. Here we show that the aridity response is substantially amplified by land–atmosphere feedbacks associated with the land surface’s response to climate and CO2 change. Using simulations from the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we show that global aridity is enhanced by the feedbacks of projected soil moisture decrease on land surface temperature, relative humidity and precipitation. The physiological impact of increasing atmospheric CO2 on vegetation exerts a qualitatively similar control on aridity. We reconcile these findings with previously proposed mechanisms by showing that the moist enthalpy change over land is unaffected by the land hydrological response. Thus, although oceanic warming constrains the combined moisture and temperature changes over land, land hydrology modulates the partitioning of this enthalpy increase towards increased aridity.

  13. Responses to ozone pollution of alfalfa exposed to increasing salinity levels.

    Science.gov (United States)

    Maggio, Albino; Chiarandà, Fabrizio Quaglietta; Cefariello, Roberto; Fagnano, Massimo

    2009-05-01

    Stomatal closure and biosynthesis of antioxidant molecules are two fundamental components of the physiological machinery that lead to stress adaptation during plant's exposure to salinity. Since high stomatal resistance may also contribute in counteracting O(3) damages, we hypothesized that soil salinization may increase O(3) tolerance of crops. An experiment was performed with alfalfa grown in filtered (AOT40=0 in both years) and non-filtered (AOT40=9.7 in 2005 and 6.9 ppm h in 2006) open-top chambers. Alfalfa yield was reduced by O(3) (-33%) only in plants irrigated with salt-free water, while the increasing levels of soil salinity until 1.06 dS m(-1) reduced both stomatal conductance and plant O(3) uptake, thus linearly reducing O(3) effects on yield. Therefore a reliable flux-based model for assessing the effects of O(3) on crop yield should take into account soil salinity.

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

    Science.gov (United States)

    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

  15. Ozone in the Atlantic Ocean marine boundary layer

    OpenAIRE

    Patrick Boylan; Detlev Helmig; Samuel Oltmans

    2015-01-01

    Abstract In situ atmospheric ozone measurements aboard the R/V Ronald H. Brown during the 2008 Gas-Ex and AMMA research cruises were compared with data from four island and coastal Global Atmospheric Watch stations in the Atlantic Ocean to examine ozone transport in the marine boundary layer (MBL). Ozone measurements made at Tudor Hill, Bermuda, were subjected to continental outflow from the east coast of the United States, which resulted in elevated ozone levels above 50 ppbv. Ozone measurem...

  16. Increasing Access to Atmospheric Science Research at NASA Langley Research Center

    Science.gov (United States)

    Chambers, L. H.; Bethea, K. L.; LaPan, J. C.

    2013-12-01

    The Science Directorate (SD) at NASA's Langley Research Center conducts cutting edge research in fundamental atmospheric science topics including radiation and climate, air quality, active remote sensing, and upper atmospheric composition. These topics matter to the public, as they improve our understanding of our home planet. Thus, we have had ongoing efforts to improve public access to the results of our research. These efforts have accelerated with the release of the February OSTP memo. Our efforts can be grouped in two main categories: 1. Visual presentation techniques to improve science understanding: For fundamental concepts such as the Earth's energy budget, we have worked to display information in a more "digestible" way for lay audiences with more pictures and fewer words. These audiences are iPad-lovers and TV-watchers with shorter attention spans than audiences of the past. They are also educators and students who need a basic understanding of a concept delivered briefly to fit into busy classroom schedules. We seek to reach them with a quick, visual message packed with important information. This presentation will share several examples of visual techniques, such as infographics (e.g., a history of lidar at Langley and a timeline of atmospheric research, ozone garden diagrams (http://science-edu.larc.nasa.gov/ozonegarden/ozone-cycle.php); history of lidar at LaRC; DISCOVER-AQ maps. It will also share examples of animations and interactive graphics (DISCOVER-AQ); and customized presentations (e.g., to explain the energy budget or to give a general overview of research). One of the challenges we face is a required culture shift between the way scientists traditionally share knowledge with each other and the way these public audiences ingest knowledge. A cross-disciplinary communications team in SD is crucial to bridge that gap. 2. Lay research summaries to make research more accessible: Peer-reviewed publications are a primary product of the SD, with more

  17. Understanding Differences in Upper Stratospheric Ozone Response to Changes in Chlorine and Temperature as Computed Using CCMVal Models

    Science.gov (United States)

    Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Oman, L. D.

    2012-01-01

    Projections of future ozone levels are made using models that couple a general circulation model with a representation of atmospheric photochemical processes, allowing interactions among photochemical processes, radiation, and dynamics. Such models are known as chemistry and climate models (CCMs). Although developed from common principles and subject to the same boundary conditions, simulated ozone time series vary for projections of changes in ozone depleting substances (ODSs) and greenhouse gases. In the upper stratosphere photochemical processes control ozone level, and ozone increases as ODSs decrease and temperature decreases due to greenhouse gas increase. Simulations agree broadly but there are quantitative differences in the sensitivity of ozone to chlorine and to temperature. We obtain insight into these differences in sensitivity by examining the relationship between the upper stratosphere annual cycle of ozone and temperature as produced by a suite of models. All simulations conform to expectation in that ozone is less sensitive to temperature when chlorine levels are highest because chlorine catalyzed loss is nearly independent of temperature. Differences in sensitivity are traced to differences in simulated temperature, ozone and reactive nitrogen when chlorine levels are close to background. This work shows that differences in the importance of specific processes underlie differences in simulated sensitivity of ozone to composition change. This suggests a) the multi-model mean is not a best estimate of the sensitivity of upper ozone to changes in ODSs and temperature; b) the spread of values is not an appropriate measure of uncertainty.

  18. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests.

    Science.gov (United States)

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-05-06

    Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19(th) century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected.

  19. Impact of Manaus City on the Amazon Green Ocean atmosphere: Ozone production, precursor sensitivity and aerosol load

    NARCIS (Netherlands)

    Kuhn, U.; Ganzeveld, L.N.

    2010-01-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry

  20. Increasing atmospheric humidity and CO2 concentration alleviate forest mortality risk.

    Science.gov (United States)

    Liu, Yanlan; Parolari, Anthony J; Kumar, Mukesh; Huang, Cheng-Wei; Katul, Gabriel G; Porporato, Amilcare

    2017-09-12

    Climate-induced forest mortality is being increasingly observed throughout the globe. Alarmingly, it is expected to exacerbate under climate change due to shifting precipitation patterns and rising air temperature. However, the impact of concomitant changes in atmospheric humidity and CO2 concentration through their influence on stomatal kinetics remains a subject of debate and inquiry. By using a dynamic soil-plant-atmosphere model, mortality risks associated with hydraulic failure and stomatal closure for 13 temperate and tropical forest biomes across the globe are analyzed. The mortality risk is evaluated in response to both individual and combined changes in precipitation amounts and their seasonal distribution, mean air temperature, specific humidity, and atmospheric CO2 concentration. Model results show that the risk is predicted to significantly increase due to changes in precipitation and air temperature regime for the period 2050-2069. However, this increase may largely get alleviated by concurrent increases in atmospheric specific humidity and CO2 concentration. The increase in mortality risk is expected to be higher for needleleaf forests than for broadleaf forests, as a result of disparity in hydraulic traits. These findings will facilitate decisions about intervention and management of different forest types under changing climate.

  1. Water cycle dynamic increases resilience of vegetation under higher atmospheric carbon dioxide concentration

    Science.gov (United States)

    Lemordant, L. A.; Gentine, P.; Stéfanon, M.; Drobinski, P. J.; Fatichi, S.

    2015-12-01

    Plant stomata couple the energy, water and carbon cycles. Photosynthesis requires stomata to open to take up carbon dioxide. In the process water vapor is released as transpiration. As atmospheric CO2 concentration rises, for the same amount of CO2 uptake, less water vapor is transpired, translating into higher water use efficiency. Reduced water vapor losses will increase soil water storage if the leaf area coverage remains similar. This will in turn alter the surface energy partitioning: more heat will be dissipated as sensible heat flux, resulting in possibly higher surface temperatures. In contrast with this common hypothesis, our study shows that the water saved during the growing season by increased WUE can be mobilized by the vegetation and help reduce the maximum temperature of mid-latitude heat waves. The large scale meteorological conditions of 2003 are the basis of four regional model simulations coupling an atmospheric model to a surface model. We performed two simulations with respectively 2003 (CTL) and 2100 (FUT) atmospheric CO2 applied to both the atmospheric and surface models. A third (RAD) and a fourth (FER) simulations are run with 2100 CO2 concentration applied to respectively the atmospheric model only and the surface model only. RAD investigates the impact of the radiative forcing, and FER the response to vegetation CO2 fertilization. Our results show that the water saved through higher water use efficiency during the growing season enabled by higher atmospheric carbon dioxide concentrations helps the vegetation to cope during severe heat and dryness conditions in the summer of mid-latitude climate. These results demonstrate that consideration of the vegetation carbon cycle is essential to model the seasonal water cycle dynamic and land-atmosphere interactions, and enhance the accuracy of the model outputs especially for extreme events. They also have important implications for the future of agriculture, water resources management, ecosystems

  2. Increasing Mississippi river discharge throughout the twenty-first century influenced by changes in climate, land use and atmospheric CO2

    Science.gov (United States)

    Tao, B.; Tian, H.; Ren, W.; Yang, J.; Yang, Q.; He, R.; Cai, W. J.; Lohrenz, S. E.

    2014-12-01

    Previous studies have demonstrated that changes in temperature and precipitation (hereafter climate change) would influence river discharge, but the relative importance of climate change, land use, and elevated atmospheric CO2 have not yet been fully investigated. Here we examined how river discharge in the Mississippi River basin in the 21st century might be influenced by these factors using the Dynamic Land Ecosystem Model driven by atmospheric CO2, downscaled GCMs climate and land use scenarios. Our results suggest that river discharge would be substantially enhanced (10.7-59.8%) by the 2090s compared to the recent decade (2000s), though large discrepancies exist among different climate, atmospheric CO2, and land use change scenarios. Our factorial analyses further indicate that the combined effects of land use change and human-induced atmospheric CO2 elevation on river discharge would outweigh climate change effect under the high emission scenario (A2) of Intergovernmental Panel for Climate Change. Our study offers the first attempt to project potential changes in river discharge in response to multiple future environmental changes. It demonstrates the importance of land use change and atmospheric CO2 concentrations in projecting future changes in hydrologic processes. The projected increase river discharge implies that riverine fluxes of carbon, nutrients and pesticide from the MRB to the coastal regions would increase in the future, and thus may influence the states of ocean acidification and hypoxia and deteriorate ocean water quality. Further efforts will also be needed to account for additional environmental factors (such as nitrogen deposition, tropospheric ozone pollution, dam construction, etc.) in projecting changes in the hydrological cycle.

  3. Has the sensitivity of soybean cultivars to ozone pollution increased with time? An analysis of published dose-response data.

    Science.gov (United States)

    Osborne, Stephanie A; Mills, Gina; Hayes, Felicity; Ainsworth, Elizabeth A; Büker, Patrick; Emberson, Lisa

    2016-09-01

    The rising trend in concentrations of ground-level ozone (O3 ) - a common air pollutant and phytotoxin - currently being experienced in some world regions represents a threat to agricultural yield. Soybean (Glycine max (L.) Merr.) is an O3 -sensitive crop species and is experiencing increasing global demand as a dietary protein source and constituent of livestock feed. In this study, we collate O3 exposure-yield data for 49 soybean cultivars, from 28 experimental studies published between 1982 and 2014, to produce an updated dose-response function for soybean. Different cultivars were seen to vary considerably in their sensitivity to O3 , with estimated yield loss due to O3 ranging from 13.3% for the least sensitive cultivar to 37.9% for the most sensitive, at a 7-h mean O3 concentration (M7) of 55 ppb - a level frequently observed in regions of the USA, India and China in recent years. The year of cultivar release, country of data collection and type of O3 exposure used were all important explanatory variables in a multivariate regression model describing soybean yield response to O3 . The data show that the O3 sensitivity of soybean cultivars increased by an average of 32.5% between 1960 and 2000, suggesting that selective breeding strategies targeting high yield and high stomatal conductance may have inadvertently selected for greater O3 sensitivity over time. Higher sensitivity was observed in data from India and China compared to the USA, although it is difficult to determine whether this effect is the result of differential cultivar physiology, or related to local environmental factors such as co-occurring pollutants. Gaining further understanding of the underlying mechanisms that govern the sensitivity of soybean cultivars to O3 will be important in shaping future strategies for breeding O3 -tolerant cultivars. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  4. Atmospheric evidence for a global secular increase in carbon isotopic discrimination of land photosynthesis

    Science.gov (United States)

    Keeling, Ralph F.; Graven, Heather D.; Welp, Lisa R.; Resplandy, Laure; Bi, Jian; Piper, Stephen C.; Sun, Ying; Bollenbacher, Alane; Meijer, Harro A. J.

    2017-09-01

    A decrease in the 13C/12C ratio of atmospheric CO2 has been documented by direct observations since 1978 and from ice core measurements since the industrial revolution. This decrease, known as the 13C-Suess effect, is driven primarily by the input of fossil fuel-derived CO2 but is also sensitive to land and ocean carbon cycling and uptake. Using updated records, we show that no plausible combination of sources and sinks of CO2 from fossil fuel, land, and oceans can explain the observed 13C-Suess effect unless an increase has occurred in the 13C/12C isotopic discrimination of land photosynthesis. A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm-1 is largely explained by photorespiratory and mesophyll effects. This result implies that, at the global scale, land plants have regulated their stomatal conductance so as to allow the CO2 partial pressure within stomatal cavities and their intrinsic water use efficiency to increase in nearly constant proportion to the rise in atmospheric CO2 concentration.

  5. Northern European trees show a progressively diminishing response to increasing atmospheric carbon dioxide concentrations

    CSIR Research Space (South Africa)

    Waterhouse, JS

    2004-04-01

    Full Text Available of atmospheric CO2 in different ways. The reduction in sensitivity of IWUE to increasing Ca shown by most of the trees in this study may be related to the loss in climatic sensitivity of latewood relative densities in recent years. If a long-term or permanent...

  6. Solar Backscatter UV (SBUV total ozone and profile algorithm

    Directory of Open Access Journals (Sweden)

    P. K. Bhartia

    2013-10-01

    column ozone by integrating the SBUV profiles, rather than from a separate set of wavelengths, as was done in previous algorithm versions. This allows us to extend the total ozone retrieval to 88° solar zenith angle (SZA. Since the quality of total column data is affected by reduced sensitivity to ozone in the lower atmosphere by cloud and Rayleigh attenuation, which gets worse with increasing SZA, we provide our best estimate of these errors, as well as the kernels that can be used to test the sensitivity of the derived columns to long-term changes in ozone in the lower atmosphere.

  7. Evaluation of Atmospheric Electric Field as Increasing Seismic Activity Indicator on the example of Caucasus Region

    Science.gov (United States)

    Kachakhidze, M. K.; Kereselidze, Z. A.; Kachakhidze, N. K.

    2013-01-01

    The present paper deals with reliability of a gradient of atmospheric electric field potential as an indicator of seismic activity increase. With this in view, records of atmospheric electric field potential gradients of Caucasus region for 1953-1992 with respect to periods before average and large earthquakes, which took place in the same time interval, were considered. It is worth to pay attention to the fact that the avalanche-like unstable model of fault formation based on theoretical model of self-generated seismo-electromagnetic oscillations of LAI system explains convincingly spectral succession of electromagnetic emission frequency of the periods preceding earthquakes.

  8. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

    Energy Technology Data Exchange (ETDEWEB)

    Jones, M.L.M., E-mail: lj@ceh.ac.u [Centre for Ecology and Hydrology (CEH), Environment Centre Wales, Deiniol Road, Bangor, LL57 2UW Wales (United Kingdom); Hodges, G. [AMEC, Earth and Environmental UK Ltd, Unit 1, Trinity Place, Thames St, Weybridge, Surrey KT13 8JB (United Kingdom); Mills, G. [Centre for Ecology and Hydrology (CEH), Environment Centre Wales, Deiniol Road, Bangor, LL57 2UW Wales (United Kingdom)

    2010-02-15

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha{sup -1} yr{sup -1}. Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

  9. Understanding Tropospheric Ozone Variability in the Arctic

    Science.gov (United States)

    McClure-Begley, A.; Petropavlovskikh, I. V.; Crepinsek, S.; Uttal, T.; Skov, H.

    2016-12-01

    The Arctic is a region that has been subject to drastic changes in the climate partially due to transported pollutants which strongly impact the composition of the atmosphere and associated feedbacks. Tropospheric ozone is an atmospheric species formed by the reaction of precursor species (NOx, CO, VOC's) in the presence of UV radiation and drives complex interactions which can result in impacts on atmospheric conditions in the Arctic. As an important greenhouse gas, ozone has a significant influence on the photochemical characteristics, oxidation capacity, and radiative forcing of the atmosphere and at high levels has negative impacts on public health and overall ecosystem functioning. In the Arctic, tropospheric ozone has variable characteristics in time and space. Seasonal variation of ozone is controlled by many factors influencing the production and destruction of ozone. The arctic ozone conditions are strongly influenced by seasonal destruction events, arctic haze, transport of pollution from Asia and influence from precursor compounds released from wildfires. This study investigates long-term ozone variation, seasonal surface ozone conditions, and characterizes deviations from expected ozone levels at four arctic ozone measurement locations (Barrow Alaska, Tiksi Russia, Summit Greenland, and Villum Station Greenland). Frequency of ozone depletion events and high ozone episodes for each station over time provides a context for the changing conditions of ozone in the arctic. NOAA Hysplit back-trajectory analysis, satellite imagery, NOAA Smoke verification model, co-located carbon monoxide, carbon dioxide, and aerosol optical depth measurements are used to understand the dominant source of pollution, pollutant composition, and the interactions due to meteorological conditions that result in anomalies in the ozone mixing ratio records. Characterization of ozone behavior and influences on the measurement locations is essential for understanding the spatial and

  10. Evildoer or Do-Gooder: Getting the Goods on Ozone

    Science.gov (United States)

    Fisher, Diane K.

    2008-01-01

    This article describes the differences of good ozone and bad ozone. Good ozone, which is found in the stratosphere, protects people and other living things from the bad things UV can do, such skin cancer, cataracts, and other problems. However, lower in the atmosphere, at the top of the troposphere (around 12 miles up), ozone acts like a…

  11. Ozone decomposition kinetics on alumina: effects of ozone partial pressure, relative humidity and repeated oxidation cycles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2004-01-01

    Full Text Available The room temperature kinetics of gas-phase ozone loss via heterogeneous interactions with thin alumina films has been studied in real-time using 254nm absorption spectroscopy to monitor ozone concentrations. The films were prepared from dispersions of fine alumina powder in methanol and their surface areas were determined by an in situ procedure using adsorption of krypton at 77K. The alumina was found to lose reactivity with increasing ozone exposure. However, some of the lost reactivity could be recovered over timescales of days in an environment free of water, ozone and carbon dioxide. From multiple exposures of ozone to the same film, it was found that the number of active sites is large, greater than 1.4x1014 active sites per cm2 of surface area or comparable to the total number of surface sites. The films maintain some reactivity at this point, which is consistent with there being some degree of active site regeneration during the experiment and with ozone loss being catalytic to some degree. The initial uptake coefficients on fresh films were found to be inversely dependent on the ozone concentration, varying from roughly 10-6 for ozone concentrations of 1014 molecules/cm3 to 10-5 at 1013 molecules/cm3. The initial uptake coefficients were not dependent on the relative humidity, up to 75%, within the precision of the experiment. The reaction mechanism is discussed, as well as the implications these results have for assessing the effect of mineral dust on atmospheric oxidant levels.

  12. UPPER TROPOSPHERIC ND STR TOSPHERIC OZONE OVER ...

    African Journals Online (AJOL)

    USER

    2015-03-26

    Mar 26, 2015 ... from ERA-interim, gridded at 0.75 degree resolution (Dee et al., 2011) was used in this study to ..... A.H. (2009). Increasing ozone in marine boundary layer inflow at the west coasts of North America and. Europe. Atmospheric Chemistry and. Physics,. 9:1303-1323, doi:10.5194/acp-9-1303-2009. Dee, D.P. ...

  13. Increases in Atmospheric Chlorine from Dichloromethane, a Gas Not Controlled by the Montreal Protocol.

    Science.gov (United States)

    Montzka, S. A.; Hossaini, R.; Hall, B. D.; Hu, L.; Miller, B.; Siso, C.; Andrews, A. E.; Sweeney, C.; Elkins, J. W.; Chipperfield, M.

    2015-12-01

    Short-lived, anthropogenically produced chlorinated gases historically have not been controlled by the Montreal Protocol; their contribution to stratospheric halogen loading has been relatively small and constant. Since 2000, however, tropospheric mole fractions of dichloromethane (mean lifetime of 5 months) have increased by a factor of 2 at remote sites throughout the globe. Dichloromethane currently adds more chlorine to the atmosphere (~80 ppt) than either HCFC-141b or HCFC-142b, and the implied resulting increase in stratospheric chlorine in recent years is comparable to the increase in total Cl from HCFCs. Emissions driving this global increase have been estimated at 800 Gg/yr in 2012, which is more than half of the chlorine emitted from the three main CFCs during their peak emissions in the late 1980s. Although dichloromethane is used typically as a cleaning agent, solvent, and feedstock in the production of other chemicals, the cause of the recent atmospheric increase is not well understood. Here we will show that the substantial increase in emissions does not appear to be coming from the U.S., as our ongoing observations from tall towers and aircraft profiles over North America since 2005 show a decreasing trend in measured mole fractions in the continental boundary layer relative to the background atmosphere during this period. Instead, our data from remote sites across the Northern Hemisphere reveal a shift in the atmospheric distribution of dichloromethane since 2000 that implies increased emissions from lower latitudes in the northern hemisphere. These changing distributions will be presented and discussed, along with an exploration of the potential causes for the large inter-annual variations observed in the rate of increase and what the results suggest about the main loss mechanism for dichloromethane: oxidation by the hydroxyl radical.

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

    Science.gov (United States)

    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.

  15. Ozone formation in pulsed SDBD in a wide pressure range

    Science.gov (United States)

    Starikovskiy, Andrey; Nudnova, Maryia; mipt Team

    2011-10-01

    Ozone concentration in surface anode-directed DBD for wide pressure range (150 - 1300 torr) was experimentally measured. Voltage and pressure effect were investigated. Reduced electric field was measured for anode-directed and cathode-directed SDBD. E/n values in cathode-directed SDBD is higher than in cathode-directed on 50 percent at atmospheric pressure. E/n value increase leads to decrease the rate of oxygen dissociation and Ozone formation at lower pressures. Radiating region thickness of sliding discharge was measured. Typical thickness of radiating zone is 0.4-1.0 mm within pressure range 220-740 torr. It was shown that high-voltage pulsed nanosecond discharge due to high E/n value produces less Ozone with compare to other discharges. Kinetic model was proposed to describe Ozone formation in the pulsed nanosecond SDBD.

  16. Net photosynthesis in Sphagnum mosses has increased in response to the last century's 100 ppm increase in atmospheric CO2

    Science.gov (United States)

    Serk, Henrik; Nilsson, Mats; Schleucher, Jurgen

    2017-04-01

    Peatlands store >25% of the global soil C pool, corresponding to 1/3 of the contemporary CO2-C in the atmosphere. The majority of the accumulated peat is made up by remains of Sphagnum peat mosses. Thus, understanding how various Sphagnum functional groups respond, and have responded, to increasing atmospheric CO2 and temperature constitutes a major challenge for our understanding of the role of peatlands under a changing climate. We have recently demonstrated (Ehlers et al., 2015, PNAS) that the abundance ratio of two deuterium isotopomers (molecules carrying D at specific intramolecular positions, here D6R/S) of photosynthetic glucose reflects the ratio of oxygenation to carboxylation metabolic fluxes at Rubisco. The photosynthetic glucose is prepared from various plant carbohydrates including cellulose. This finding has been established in CO2 manipulation experiments and observed in carbohydrate derived glucose isolated from herbarium samples of all investigated C-3 species. The isotopomer ratio is connected to specific enzymatic processes thus allowing for mechanistic implicit interpretations. Here we demonstrate a clear increase in net photosynthesis of Sphagnum fuscum in response to the increase of 100 ppm CO2 during the last century as deduced from analysis on S. fuscum remains from peat cores. The D6R/S ratio declines from bottom to top in peat cores, indicating CO2-driven reduction of photorespiration in contemporary moss biomass. In contrast to the hummock-forming S. fuscum, hollow-growing species, e.g. S. majus did not show this response or gave significantly weaker response, suggesting important ecological consequences of rising CO2 on peatland ecosystem services. We hypothesize that photosynthesis in hollow-growing species under water saturation is fully or partly disconnected from the atmospheric CO2 partial pressure and thus showing weaker or no response to increased atmospheric CO2. To further test the field observations we grow both hummock and

  17. Stratospheric ozone: History and concepts and interactions with climate

    Directory of Open Access Journals (Sweden)

    Bekki S.

    2009-02-01

    Full Text Available Although in relatively low concentration of a few molecules per million of e e air molecules, atmospheric ozone (trioxygen O3 is essential to sustaining life on the surface of the Earth. Indeed, by absorbing solar radiation between 240 and 320 nm, it shields living organisms including humans from the very harmful ultraviolet radiation UV-B. About 90% of the ozone resides in the stratosphere, a region that extends from the tropopause, whose altitude ranges from 7 km at the poles to 17 km in the tropics, to the stratopause located at about 50 km altitude. Stratospheric ozone is communally referred as the « ozone layer ». Unlike the atmosphere surrounding it, the stratosphere is vertically stratified and stable because the temperature increases with height within it. This particularity originates from heating produced by the absorption of UV radiation by stratospheric ozone. The present chapter describes the main mechanisms that govern the natural balance of ozone in the stratosphere, and its disruption under the influence of human activities.

  18. Model of risk of cortical cataract in the US population with exposure to increased ultraviolet radiation due to stratospheric ozone depletion.

    Science.gov (United States)

    West, Sheila K; Longstreth, Janice D; Munoz, Beatriz E; Pitcher, Hugh M; Duncan, Donald D

    2005-12-01

    The authors modeled the possible consequences for US cataract incidence of increases in ultraviolet B radiation due to ozone depletion. Data on the dose-response relation between ocular exposure to ultraviolet B radiation and cortical cataract were derived from a population-based study (the Salisbury Eye Evaluation Project, Salisbury, Maryland) in which extensive data on cataract and ultraviolet radiation were collected in persons aged 65-84 years. Exposure estimates for the US population were derived using estimated ultraviolet radiation fluxes as a function of wavelength. US Census data were used to obtain the age, ethnicity, and sex distribution of the population. Predicted probabilities of cataract were derived from the age-, sex-, and ethnicity-specific ocular ultraviolet exposure data and were modeled under conditions of 5-20% ozone depletion. The analysis indicated that by 2050, the prevalence of cortical cataract will increase above expected levels by 1.3-6.9%. The authors estimate that with 5-20% ozone depletion, there will be 167,000-830,000 additional cases of cortical cataract by 2050. Because of the high prevalence of cataract in older persons, at a 2003 cost of 3,370 dollars per cataract operation, this increase could represent an excess cost of 563 million dollars to 2.8 billion dollars.

  19. Water disinfection with ozone, copper and silver ions, and temperature increase to control Legionella: seven years of experience in a university teaching hospital.

    Science.gov (United States)

    Blanc, D S; Carrara, Ph; Zanetti, G; Francioli, P

    2005-05-01

    The efficacy of ozonation, copper-silver ionization and increased temperature in controlling Legionella spp. in the hot water distribution networks of a university hospital was evaluated. Two separate water distribution networks were studied; network 1 which supplies the surgical intensive care units, and network 2 which supplies the medical intensive care units and the emergency room. Network 1 has been disinfected by ozonation since 1995, and network 2 has been disinfected by ionisation since 1999. The hot water temperature was increased from 50 to 65 degrees C in 1998 and 2000 in networks 1 and 2, respectively. Water samples and swabs of the water outlets were cultured for Legionella spp. between four and six times each year, providing data before and after implementation of the disinfection procedures. There was no significant difference in the proportion of samples positive for Legionella spp. after ozonation in network 1 or after ionization in network 2. In both networks, there was a significant reduction in legionella isolates after increasing the hot water temperature to 65 degrees C. Maintaining the hot water temperature above 50 degrees C throughout both networks proved to be the most effective control measure in our hospital.

  20. The impact of decreases in air temperature and increases in ozone on markers of endothelial function in individuals having type-2 diabetes.

    Science.gov (United States)

    Lanzinger, Stefanie; Breitner, Susanne; Neas, Lucas; Cascio, Wayne; Diaz-Sanchez, David; Hinderliter, Alan; Peters, Annette; Devlin, Robert B; Schneider, Alexandra

    2014-10-01

    Several studies have reported an association between air pollution and endothelial dysfunction, especially in individuals having diabetes. However, very few studies have examined the impact of air temperature on endothelial function. The objective of this analysis was to investigate short-term effects of temperature and ozone on endothelial function in individuals having diabetes. Moreover, we investigated interactive effects between air temperature and air pollution on markers of endothelial function. Between November 2004 and December 2005 flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NTGMD) and several blood markers representing endothelial function were measured using brachial artery ultrasound on four consecutive days in 22 individuals with type-2 diabetes mellitus in Chapel Hill, North Carolina (USA). Daily measurements of meteorological parameters, ozone and particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5) were obtained from fixed monitoring sites. We used additive mixed-models adjusting for time trend, day of the week, relative humidity and barometric pressure to assess temperature and ozone associations with endothelial function. A 1 °C decrease in the 24-h temperature average was associated with a decrease in mean FMD on the same day (-2.2% (95%-confidence interval:[-4.7;0.3%])) and with a delay of one and four days. A temperature decrement also led to an immediate (-1.7%[-3.3;-0.04]) decrease in NTGMD. Moreover, we observed an immediate (-14.6%[-26.3;-2.9%]) and a one day delayed (-13.5%[-27.0; 0.04%]) decrease in FMD in association with a 0.01 ppm increase in the maximum 8-h moving average of ozone. Temperature effects on FMD strengthened when PM2.5 and ozone concentrations were high. The associations were similar during winter and summer. We detected an association between temperature decreases and ozone increases on endothelial dysfunction in individuals having diabetes. We conclude that endothelial dysfunction

  1. The evolution of zonally asymmetric austral ozone in a chemistry-climate model

    Science.gov (United States)

    Dennison, Fraser; McDonald, Adrian; Morgenstern, Olaf

    2017-11-01

    Asymmetry in the Southern Hemisphere stratospheric ozone hole is important due to both direct radiative heating and its effect on dynamics. It is also a strong indicator of the underlying quality of the stratospheric dynamics of a climate model. We investigate the simulation of the zonal asymmetry in ozone in the NIWA-UKCA atmosphere-ocean chemistry-climate model using elliptical diagnostics, a methodology used for the first time in this subject area. During spring, the region most depleted in ozone is displaced from the pole toward South America based on ERA-Interim and the model output. The model correctly simulates the direction of this displacement but significantly underestimates its magnitude. The model shows that as ozone becomes increasingly depleted over the late 20th century this asymmetry in the ozone distribution moves west, before moving east as polar ozone recovers over the course of the 21st century. Comparison with model runs in which ozone-depleting substances are held fixed at pre-ozone-hole levels shows that this shift is primarily a function of the magnitude of ozone depletion, although increases in greenhouse gases also have some effect.

  2. Ecological issues related to ozone: agricultural issues.

    Science.gov (United States)

    Fuhrer, Jürg; Booker, Fitzgerald

    2003-06-01

    Research on the effects of ozone on agricultural crops and agro-ecosystems is needed for the development of regional emission reduction strategies, to underpin practical recommendations aiming to increase the sustainability of agricultural land management in a changing environment, and to secure food supply in regions with rapidly growing populations. Major limitations in current knowledge exist in several areas: (1) Modelling of ozone transfer and specifically stomatal ozone uptake under variable environmental conditions, using robust and well-validated dynamic models that can be linked to large-scale photochemical models lack coverage. (2) Processes involved in the initial reactions of ozone with extracellular and cellular components after entry through the stomata, and identification of key chemical species and their role in detoxification require additional study. (3) Scaling the effects from the level of individual cells to the whole-plant requires, for instance, a better understanding of the effects of ozone on carbon transport within the plant. (4) Implications of long-term ozone effects on community and whole-ecosystem level processes, with an emphasis on crop quality, element cycling and carbon sequestration, and biodiversity of pastures and rangelands require renewed efforts. The UNECE Convention on Long Range Trans-boundary Air Pollution shows, for example, that policy decisions may require the use of integrated assessment models. These models depend on quantitative exposure-response information to link quantitative effects at each level of organization to an effective ozone dose (i.e., the balance between the rate of ozone uptake by the foliage and the rate of ozone detoxification). In order to be effective in a policy, or technological context, results from future research must be funnelled into an appropriate knowledge transfer scheme. This requires data synthesis, up-scaling, and spatial aggregation. At the research level, interactions must be

  3. Examination of the atmospheric conditions associated with high and low summer ozone levels in the lower troposphere over the eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    P. D. Kalabokas

    2013-10-01

    Full Text Available In order to evaluate the observed high rural ozone levels in the eastern Mediterranean area during summertime, vertical profiles of ozone measured in the period 1994–2008 in the framework of the MOZAIC project (Measurement of Ozone and Water Vapor by Airbus in Service Aircraft over the eastern Mediterranean basin (Cairo, Tel Aviv, Heraklion, Rhodes, Antalya were analyzed, focusing in the lower troposphere (1.5–5 km. At first, vertical profiles collected during extreme days with very high or very low tropospheric ozone mixing ratios have been examined together with the corresponding back-trajectories. Also, the average profiles of ozone, relative humidity, carbon monoxide, temperature gradient and wind speed corresponding to the 7% highest and the 7% lowest ozone mixing ratios for the 1500–5000 m height layer for Cairo and Tel Aviv have been examined and the corresponding composite maps of geopotential heights at 850 hPa have been plotted. Based on the above analysis, it turns out that the lower-tropospheric ozone variability over the eastern Mediterranean area is controlled mainly by the synoptic meteorological conditions, combined with local topographical and meteorological features. In particular, the highest ozone concentrations in the lower troposphere and subsequently in the boundary layer are associated with large-scale subsidence of ozone-rich air masses from the upper troposphere under anticyclonic conditions while the lowest ozone concentrations are associated with low pressure conditions inducing uplifting of boundary-layer air, poor in ozone and rich in relative humidity, to the lower troposphere.

  4. Four years of ozone measurements in the Central Amazon - Effects of increasing deforestation rates and different meteorological conditions on near surface concentrations

    Science.gov (United States)

    Wolff, Stefan; Tsokankunku, Anywhere; Pöhlker, Christopher; Saturno, Jorge; Walter, David; Ditas, Florian; Könemann, Tobias; Ganzeveld, Laurens; Yañez-Serrano, Ana Maria; Souza, Rodrigo; Trebs, Ivonne; Sörgel, Matthias

    2017-04-01

    The ATTO (Amazon Tall Tower Observatory) site (02°08'38.8''S, 58°59'59.5''W) is located in the remote Amazon rainforest, allowing atmospheric and forest studies away from nearby anthropogenic emission sources. Starting with continuous measurements of vertical mixing ratio profiles of H2O, CO2 and O3 in April 2012 at 8 heights between 0.05 m and 80 m above ground, the longest continuous record of near surface O3 in the Amazon rainforest was established. Black carbon (BC), CO and micrometeorological measurements are available for the same period. During intensive campaigns, NOx was measured as well using the same profile system, and, therefore several month of simultaneous NOx measurements are available. During a period of about four months also direct flux measurements of O3 are available. Here, we analyze the long term and seasonal variability of near surface O3 mixing ratios with respect to air pollution, deposition and transport. The Central Amazon is characterized by a clear seasonal precipitation pattern (ca. 350 mm around March and ca. 80 mm around September), correlating strongly with ozone mixing ratios. Since 2012 deforestation rates have increased again in the Amazon, leading to higher air pollution especially during the drier season in the last years. For several strong pollution events we compared the effects of long and short distance biomass burning on O3 and NOx mixing ratios using back trajectories and satellite data. By comparing O3 mixing ratios with solar radiation, Bowen ratio, several trace gases and aerosol loads (Volatile Organic Compounds, CO and BC), different correlation patterns throughout the year that are linked to the sources (transport of O3 and precursors) and sinks (stomatal uptake and chemical reactions) are investigated. For example, the last months of 2015 were strongly influenced by an extraordinary El Niño phenomenon, leading to much drier conditions and enhanced biomass burning in the Amazon, which prolonged the period of

  5. Ozone: Genesis, effects, hazards; Ozon: Entstehung, Wirkung, Risiken

    Energy Technology Data Exchange (ETDEWEB)

    Sandermann, H.

    2001-07-01

    An international expert explains the structure and function of ozone, the anthropogenic changes in ozone concentrations and the ozone increase in the summer season as well as the main aspects of 'summer smog' and 'ozone depletion'. [German] In diesem Buch erlaeutert ein international anerkannter Experte Aufbau und natuerliche Funktionen des Ozons, er beschreibt sein veraendertes Auftreten in unserer natuerlichen Umwelt sowie das Zustandekommen von Grenzwerten, und er erklaert die wichtigsten Aspekte von ''Sommersmog'' und ''Ozonloch''. (orig.)

  6. Snowpack-atmosphere gas exchanges of carbon dioxide, ozone, and nitrogen oxides at a hardwood forest site in northern Michigan

    Directory of Open Access Journals (Sweden)

    Brian Seok

    2015-03-01

    Full Text Available Abstract Snowpack-atmosphere gas exchanges of CO2, O3, and NOx (NO + NO2 were investigated at the University of Michigan Biological Station (UMBS, a mid-latitude, low elevation hardwood forest site, during the 2007–2008 winter season. An automated trace gas sampling system was used to determine trace gas concentrations in the snowpack at multiple depths continuously throughout the snow-covered period from two adjacent plots. One natural plot and one with the soil covered by a Tedlar sheet were setup for investigating whether the primary source of measured trace gases was biogenic (i.e., from the soil or non-biogenic (i.e., from the snowpack. The results were compared with the “White on Green” study conducted at the Niwot Ridge (NWT Long Term Ecological Research site in Colorado. The average winter CO2 flux ± s.e. from the soil at UMBS was 0.54 ± 0.037 µmol m-2 s-1 using the gradient diffusion method and 0.71 ± 0.012 µmol m-2 s-1 using the eddy covariance method, and in a similar range as found for NWT. Observed snowpack-O3 exchange was also similar to NWT. However, nitrogen oxides (NOx fluxes from snow at UMBS were 10 times smaller than those at NWT, and fluxes were bi-directional with the direction of the flux dependent on NOx concentrations in ambient air. The compensation point for the change in the direction of NOx flux was estimated to be 0.92 nmol mol-1. NOx in snow also showed diurnal dependency on incident radiation. These NOx dynamics in the snow at UMBS were notably different compared to NWT, and primarily determined by snow-atmosphere interactions rather than by soil NOx emissions.

  7. Radical budget and ozone chemistry during autumn in the atmosphere of an urban site in central China

    Science.gov (United States)

    Lu, Xingcheng; Chen, Nan; Wang, Yuhang; Cao, Wenxiang; Zhu, Bo; Yao, Teng; Fung, Jimmy C. H.; Lau, Alexis K. H.

    2017-03-01

    The ROx (=OH + HO2 + RO2) budget and O3 production at an urban site in central China (Wuhan) during autumn were simulated and analyzed for the first time using a UW Chemical Model 0-D box model constrained by in situ observational data. The daytime average OH, HO2, and RO2 concentrations were 2.2 × 106, 1.0 × 108, and 5.2 × 107 molecules cm-3, respectively. The average daytime O3 production rate was 8.8 ppbv h-1, and alkenes were the most important VOC species for O3 formation (contributing 45%) at this site. Our sensitivity test indicated that the atmospheric environment in Wuhan during autumn belongs to the VOC-limited regime. The daily average HONO concentration at this site during the study period reached 1.1 ppbv and played an important role in the oxidative capacity of the atmosphere. Without the source of excess HONO, the average daytime OH, HO2, RO2, and O3 production rates decreased by 36%, 26%, 27%, and 31% respectively. A correlation between the HONO to NO2 heterogeneous conversion efficiency and PM2.5 × SWR was found at this site; based on this relationship, if the PM2.5 concentration met the World Health Organization air quality standard (25 µg m-3), the O3 production rate in this city would decrease by 19% during late autumn. The burning of agricultural biomass severely affected the air quality in Wuhan during summer and autumn. Agricultural burning was found to account for 18% of the O3 formation during the study period. Our results suggest that VOC control and a ban on agricultural biomass burning should be considered as high-priority measures for improving the air quality in this region.

  8. Two-dimensional gas chromatography with electron capture detection for the analysis of atmospheric ozone depleting halocarbons.

    Science.gov (United States)

    Ou-Yang, Chang-Feng; Hua, Hsi-Che; Chou, Yu-Chieh; Teng, Ming-Kai; Liu, Wen-Tzu; Wang, Jia-Lin

    2017-05-26

    This study is to develop a GC×GC method with electron capture detection (ECD) to analyze atmospheric halocarbons in the concentration range of parts per trillion by volume (pptv). To enrich atmospheric halocarbons a home-built thermal desorption (TD) device was coupled to the GC×GC-ECD. The technique of flow modulation was adopted using a Deans switch for GC×GC. Several column combinations of first and second dimensions were tested and the column set of DB-5×TG-1301 was found to show the best orthogonality for halocarbons. A series of modulation parameters were tested for their optimal settings. The modulation period (PM) was found to have minimal wrap-around when set at 3s. The modulation ratio (MR) was determined to be 7.82 to ensure reproducible results and maximum sensitivity. The modulation duty cycle (DC) was calculated to be approximately 0.17. Nine halocarbons were separated successfully and seven were calibrated with the use of a certified standard gas mixture. The correlation coefficients (R2) were greater than 0.9972. The reproducibility was better than 1.90% as expressed in relative standard deviation (RSD; N=30) and the detection limits were in the range of pptv for the target halocarbons. A field test by continuous analyzing ambient air with hourly resolution was performed to show the stability of the method as suggested by the homogeneity of certain halocarbons, while also reflecting concentration variation for others when emissions did arise. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Modeling the reactivities of hydroxyl radical and ozone towards atmospheric organic chemicals using quantitative structure-reactivity relationship approaches.

    Science.gov (United States)

    Gupta, Shikha; Basant, Nikita; Mohan, Dinesh; Singh, Kunwar P

    2016-07-01

    The persistence and the removal of organic chemicals from the atmosphere are largely determined by their reactions with the OH radical and O3. Experimental determinations of the kinetic rate constants of OH and O3 with a large number of chemicals are tedious and resource intensive and development of computational approaches has widely been advocated. Recently, ensemble machine learning (EML) methods have emerged as unbiased tools to establish relationship between independent and dependent variables having a nonlinear dependence. In this study, EML-based, temperature-dependent quantitative structure-reactivity relationship (QSRR) models have been developed for predicting the kinetic rate constants for OH (kOH) and O3 (kO3) reactions with diverse chemicals. Structural diversity of chemicals was evaluated using a Tanimoto similarity index. The generalization and prediction abilities of the constructed models were established through rigorous internal and external validation performed employing statistical checks. In test data, the EML QSRR models yielded correlation (R (2)) of ≥0.91 between the measured and the predicted reactivities. The applicability domains of the constructed models were determined using methods based on descriptors range, Euclidean distance, leverage, and standardization approaches. The prediction accuracies for the higher reactivity compounds were relatively better than those of the low reactivity compounds. Proposed EML QSRR models performed well and outperformed the previous reports. The proposed QSRR models can make predictions of rate constants at different temperatures. The proposed models can be useful tools in predicting the reactivities of chemicals towards OH radical and O3 in the atmosphere.

  10. Ozonated Olive Oils and Troubles

    Directory of Open Access Journals (Sweden)

    Bulent Uysal

    2014-04-01

    Full Text Available One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users. [J Intercult Ethnopharmacol 2014; 3(2.000: 49-50

  11. Atmosphere-ocean ozone fluxes during the TexAQS 2006, STRATUS 2006, GOMECC 2007, GasEx 2008, and AMMA 2008 cruises

    NARCIS (Netherlands)

    Helmig, D.; Lang, E.K.; Bariteau, L.; Boylan, P.; Fairall, C.W.; Ganzeveld, L.N.; Hare, J.E.; Hueber, J.; Pallandt, M.

    2012-01-01

    A ship-based eddy covariance ozone flux system was deployed to investigate the magnitude and variability of ozone surface fluxes over the open ocean. The flux experiments were conducted on five cruises on board the NOAA research vessel Ronald Brown during 2006-2008. The cruises covered the Gulf of

  12. Hemiparasite abundance in an alpine treeline ecotone increases in response to atmospheric CO(2) enrichment.

    Science.gov (United States)

    Hättenschwiler, Stephan; Zumbrunn, Thomas

    2006-02-01

    Populations of the annual hemiparasites Melampyrum pratense L. and Melampyrum sylvaticum L. were studied at the treeline in the Swiss Alps after 3 years of in situ CO(2) enrichment. The total density of Melampyrum doubled to an average of 44 individuals per square meter at elevated CO(2) compared to ambient CO(2). In response to elevated CO(2), the height of the more abundant and more evenly distributed M. pratense increased by 20%, the number of seeds per fruit by 21%, and the total seed dry mass per fruit by 27%, but the individual seed size did not change. These results suggest that rising atmospheric CO(2) may stimulate the reproductive output and increase the abundance of Melampyrum in the alpine treeline ecotone. Because hemiparasites can have important effects on community dynamics and ecosystem processes, notably the N cycle, changing Melampyrum abundance may potentially influence the functioning of alpine ecosystems in a future CO(2)-rich atmosphere.

  13. Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

    Directory of Open Access Journals (Sweden)

    P. J. Nowack

    2016-03-01

    Full Text Available Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM. Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  14. Cosmic-ray-driven electron-induced reactions of halogenated molecules adsorbed on ice surfaces: Implications for atmospheric ozone depletion and global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Lu Qingbin [Department of Physics and Astronomy and Departments of Biology and Chemistry, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada)], E-mail: qblu@uwaterloo.ca

    2010-02-15

    The cosmic-ray-driven electron-induced reaction of halogenated molecules adsorbed on ice surfaces has been proposed as a new mechanism for the formation of the polar ozone hole. Here, experimental findings of dissociative electron transfer reactions of halogenated molecules on ice surfaces in electron stimulated desorption, electron trapping and femtosecond time-resolved laser spectroscopic measurements are reviewed. This is followed by a review of the evidence from recent satellite observations of this new mechanism for the Antarctic ozone hole, and all other possible physical mechanisms are discussed. Moreover, new observations of the 11-year cyclic variations of both polar ozone loss and stratospheric cooling and the seasonal variations of CFCs and CH{sub 4} in the polar stratosphere are presented, and quantitative predictions of the Antarctic ozone hole in the future are given. Finally, a new observation of the effects of CFCs and cosmic-ray-driven ozone depletion on global climate change is also presented and discussed.

  15. Critical discussion on the UV absorption properties of Earth's atmosphere

    Science.gov (United States)

    Döhring, Thorsten

    2017-08-01

    Suńs ultraviolet radiation is classified into UV-A, UV-B, and UV-C bands. Thereby UV-A passes through Eart&hacute;s atmosphere, while UV-B is partially absorbed by ozone. The limitations of the commonly accepted statement, that UV-C is always completely absorbed by Eart&hacute;s atmosphere, are discussed critically. Below 200 nm the solar spectrum is strongly absorbed by molecular oxygen. The stratospheric ozone layer has strong absorption between 200 nm and 300 nm. However, the "ozone hole" increases UV-B radiation just below 300 nm and may also open a transmitting atmospheric window for harmful UV-C at the overlap region between oxygen absorption and ozone absorption.

  16. Douglas-fir seedlings exhibit metabolic responses to increased temperature and atmospheric drought.

    Directory of Open Access Journals (Sweden)

    Kirstin Jansen

    Full Text Available In the future, periods of strongly increased temperature in concert with drought (heat waves will have potentially detrimental effects on trees and forests in Central Europe. Norway spruce might be at risk in the future climate of Central Europe. However, Douglas-fir is often discussed as an alternative for the drought and heat sensitive Norway spruce, because some provenances are considered to be well adapted to drier and warmer conditions. In this study, we identified the physiological and growth responses of seedlings from two different Douglas-fir provenances to increased temperature and atmospheric drought during a period of 92 days. We analysed (i plant biomass, (ii carbon stable isotope composition as an indicator for time integrated intrinsic water use efficiency, (iii apparent respiratory carbon isotope fractionation as well as (iv the profile of polar low molecular metabolites. Plant biomass was only slightly affected by increased temperatures and atmospheric drought but the more negative apparent respiratory fractionation indicated a temperature-dependent decrease in the commitment of substrate to the tricarboxylic acid cycle. The metabolite profile revealed that the simulated heat wave induced a switch in stress protecting compounds from proline to polyols. We conclude that metabolic acclimation successfully contributes to maintain functioning and physiological activity in seedlings of both Douglas-fir provenances under conditions that are expected during heat waves (i.e. elevated temperatures and atmospheric drought. Douglas-fir might be a potentially important tree species for forestry in Central Europe under changing climatic conditions.

  17. A two-dimensional model with coupled dynamics, radiative transfer, and photochemistry. 2: Assessment of the response of stratospheric ozone to increased levels of CO2, N2O, CH4, and CFC

    Science.gov (United States)

    Schneider, Hans R.; Ko, Malcolm K. W.; Shia, Run-Lie; Sze, Nien-Dak

    1993-01-01

    The impact of increased levels of carbon dioxide (CO2), chlorofluorocarbons (CFCs), and other trace gases on stratospheric ozone is investigated with an interactive, two-dimensional model of gas phase chemistry, dynamics, and radiation. The scenarios considered are (1) a doubling of the CO2 concentration, (2) increases of CFCs, (3) CFC increases combined with increases of nitrous oxide (N2O) and methane CH4, and (4) the simultaneous increase of CO2, CFCs, N2O, and CH4. The radiative feedback and the effect of temperature and circulation changes are studied for each scenario. For the double CO2 calculations the tropospheric warming was specified. The CO2 doubling leads to a 3.1% increase in the global ozone content. Doubling of the CO2 concentrations would lead to a maximum cooling of about 12 C at 45 km if the ozone concentration were held fixed. The cooling of the stratosphere leads to an ozone increase with an associated increase in solar heating, reducing the maximum temperature drop by about 3 C. The CFC increase from continuous emissions at 1985 rate causes a 4.5% loss of ozone. For the combined perturbations a net loss of 1.3% is calculated. The structure of the perturbations shows a north-south asymmetry. Ozone losses (when expressed in terms of percent changes) are generally larger in the high latitudes of the southern hemisphere as a result of the eddy mixing being smaller than in the northern hemisphere. Increase of chlorine leads to ozone losses above 30 km altitude where the radiative feedback results in a cooler temperature and an ozone recovery of about one quarter of the losses predicted with a noninteractive model. In all the cases, changes in circulation are small. In the chlorine case, circulation changes reduce the calculated column depletion by about one tenth compared to offline calculations.

  18. Plant ozone injury symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Nouchi, I.; Odaira, T.; Sawada, T.; Oguchi, K.; Komeiji, T.

    1973-01-01

    A study of the phytotoxicity of ozone to plants was conducted in controlled-atmosphere greenhouses to determine if the symptoms of such exposure would be similar to symptoms exhibited by plants exposed to photochemical smog (which contains ozone) in the Tokyo area. Test plants used were herbaceous plants and woody plants, which were fumigated to 20 pphm ozone. Plants used as controls for the oxone exposure experiments were placed in a carbon filtered greenhouse. Herbaceous plants were generally sensitive to injury, especially Brassica rapa, Brassica pekinensis and others were extremely responsive species. In comparison with herbaceous plants, woody plants were rather resistant except for poplar. Depending on plant species and severity of injury, ozone-injury symptoms of herbaceous plants were bleaching, chlorosis, necrosis, and red-dish-brown flecks. Leaves of woody plants developed discrete, punctate spots, reddish-brown pigment on the upper surfaces and lastly defoliation. Ozone injury was typically confined to the upper leaf surfaces and notably greater mature leaves. Microscopic examination showed that pallisade cells were much more prone to ozone injury than other tissues.

  19. Regional-Scale Ozone Deposition to North-East Atlantic Waters

    Directory of Open Access Journals (Sweden)

    L. Coleman

    2010-01-01

    Full Text Available A regional climate model is used to evaluate dry deposition of ozone over the North East Atlantic. Results are presented for a deposition scheme accounting for turbulent and chemical enhancement of oceanic ozone deposition and a second non-chemical, parameterised gaseous dry deposition scheme. The first deposition scheme was constrained to account for sea-surface ozone-iodide reactions and the sensitivity of modelled ozone concentrations to oceanic iodide concentration was investigated. Simulations were also performed using nominal reaction rate derived from in-situ ozone deposition measurements and using a preliminary representation of organic chemistry. Results show insensitivity of ambient ozone concentrations modelled by the chemical-enhanced scheme to oceanic iodide concentrations, and iodide reactions alone cannot account for observed deposition velocities. Consequently, we suggest a missing chemical sink due to reactions of ozone with organic matter at the air-sea interface. Ozone loss rates are estimated to be in the range of 0.5–6 ppb per day. A potentially significant ozone-driven flux of iodine to the atmosphere is estimated to be in the range of 2.5–500 M molec cm−2  s−1, leading to a mixing-layer enhancement of organo-iodine concentrations of 0.1–22.0 ppt, with an average increase in the N.E. Atlantic of around 4 ppt per day.

  20. The Antarctic Ozone Hole: Initial Results from Aura / OMI Compared with TOMS

    Science.gov (United States)

    McPeters, R.; Bhartia, P. K.; Newman, P.

    2004-01-01

    A series of TOMS instruments (on November 7 , Meteor 3, and Earth Probe) has been monitoring the annual development of the Antarctic ozone hole since the 1980s. The ozone mapping instrument on Aura, OMI, is expected to take over this record of observation from the aging Earth Probe TOMS instrument. The area of the ozone hole can be taken as a sensitive indicator of the magnitude of ozone destruction each year. The timing of initial formation of the ozone hole and its duration are sensitive to the atmospheric dynamics of the southern polar regions. The entire TOMS data record (1978 - 2004) has recently been reprocessed with the new version 8 algorithm, which includes a revised calibration. The effect has been to slightly increase ozone hole area over earlier estimates, but only by 23%. OMI (ozone monitoring instrument) on Aura is a hyperspectral imaging instrument that operates in a pushbroom mode to measure solar backscattered radiation in the ultraviolet and visible. OMI has higher spatial resolution than TOMS - 14 x 24 km versus 38 km x 38 km from TOMS. OMI has now begin mapping total column ozone on a global basis in a measurement similar to TOMS. The ozone hole measurements for 2003 are compared with those from Earth Probe TOMS.

  1. The Recovery of the Antarctic Ozone Hole

    Science.gov (United States)

    Newman, Paul A.

    2004-01-01

    The ozone hole is a massive loss of ozone that annually occurs over Antarctica during the Austral spring (August-November). Man-made chlorine and bromine compounds cause the ozone hole. As opposed to local urban pollution, the hole illustrates how man-made chemicals can affect the atmosphere over enormous regions remote from their release point. These chlorine and bromine gases have long lifetimes in the atmosphere; hence, the ozone hole will slowly recover into the next few decades. In this talk I will briefly cover some of the history of the Antarctic ozone hole and the theory behind the phenomena. I will then discuss the recovery of ozone over Antarctica. State-of-the-art computer models project the recovery of the ozone hole to 1980 levels by about 2050. However, this recovery may be affected by greenhouse warming.

  2. Analysis of a rapid increase of stratospheric ozone during late austral summer 2008 over Kerguelen (49.4° S, 70.3° E

    Directory of Open Access Journals (Sweden)

    H. Bencherif

    2011-01-01

    Full Text Available This paper reports on an increase of ozone event observed over Kerguelen (49.4° S, 70.3° E in relationship with large-scale isentropic transport. This is evidenced by ground-based observations (co-localised radiosonde and SAOZ experiments together with satellite global observations (Aura/MLS assimilated into MOCAGE, a Méteo-France model.

    The study is based on the analyses of the first ozonesonde experiment never recorded at the Kerguelen site within the framework of a French campaign called ROCK that took place from April to August 2008.

    Comparisons and interpretations of the observed event are supported by co-localised SAOZ observations, by global mapping of tracers (O3, N2O and columns of O3 from Aura/MLS and Aura/OMI experiments, and by model simulations of Ertel Potential Vorticity initialised by the ECMWF (European Centre for Medium-Range Weather Forecasts data reanalyses.

    Satellite and ground-based observational data revealed a consistent increase of ozone in the local stratosphere by mid-April 2008. Additionally, Ozone (O3 and nitrous oxide (N2O profiles obtained during January–May 2008 using the Microwave Limb Sounder (MLS aboard the Aura satellite are assimilated into MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle, a global three-dimensional chemistry transport model of Météo-France. The assimilated total O3 values are consistent with SAOZ ground observations (within ±5%, and isentropic distributions of O3 match well with maps of advected potential vorticity (APV derived from the MIMOSA model, a high-resolution advection transport model, and from the ECMWF reanalysis.

    The event studied seems to be related to the isentropic transport of air masses that took place simultaneously in the lower- and middle-stratosphere, respectively from the polar region and from the tropics to the mid-latitudes.

    In

  3. Direct and ozone-mediated forcing of the Southern Annular Mode by greenhouse gases

    OpenAIRE

    Morgenstern, Olaf; Zeng, Guang; Dean, Sam M.; Joshi, Manoj; Abraham, N. Luke; Osprey, Annette

    2014-01-01

    We assess the roles of long-lived greenhouse gases and ozone depletion in driving meridional surface pressure gradients in the southern extratropics; these gradients are a defining feature of the Southern Annular Mode. Stratospheric ozone depletion is thought to have caused a strengthening of this mode during summer, with increasing long-lived greenhouse gases playing a secondary role. Using a coupled atmosphere-ocean chemistry-climate model, we show that there is cancelation between the dire...

  4. Mechanisms of impact of greenhouse gases on the Earth's ozone layer in the Polar Regions

    Science.gov (United States)

    Zadorozhny, Alexander; Dyominov, Igor

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the atmosphere including aerosol physics is used to examine the impact of the greenhouse gases CO2, CH4, and N2O on the future long-term changes of the Earth's ozone layer, in particular on its expected recovery after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. The model allows calculating self-consistently diabatic circu-lation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the North to South Poles, as well as distribution of sulphate aerosol particles and polar strato-spheric clouds (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1980 through 2050 are taken from Climate Change 2001. The processes, which determine the influence of anthropogenic growth of atmospheric abun-dance of the greenhouse gases on the long-term changes of the Earth's ozone layer in the Polar Regions, have been studied in details. Expected cooling of the stratosphere caused by increases of greenhouse gases, most importantly CO2, essentially influences the ozone layer by two ways: through temperature dependencies of the gas phase reaction rates and through enhancement of polar ozone depletion via increased PSC formation. The model calculations show that a weak-ness in efficiencies of all gas phase catalytic cycles of the ozone destruction due to cooling of the stratosphere is a dominant mechanism of the impact of the greenhouse gases on the ozone layer in Antarctic as well as at the lower latitudes. This mechanism leads to a significant acceleration of the ozone layer recovery here because of the greenhouse gases growth. On the contrary, the mechanism of the impact of the greenhouse gases on the ozone through PSC modification be-gins to be more effective in Arctic in comparison with the gas phase mechanism in springs after about 2020, which leads to retard

  5. Forecasts and assimilation experiments of the Antarctic ozone hole 2008

    Science.gov (United States)

    Flemming, J.; Inness, A.; Jones, L.; Eskes, H. J.; Huijnen, V.; Schultz, M. G.; Stein, O.; Cariolle, D.; Kinnison, D.; Brasseur, G.

    2011-03-01

    The 2008 Antarctic ozone hole was one of the largest and most long-lived in recent years. Predictions of the ozone hole were made in near-real time (NRT) and hindcast mode with the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts were carried out both with and without assimilation of satellite observations from multiple instruments to provide more realistic initial conditions. Three different chemistry schemes were applied for the description of stratospheric ozone chemistry: (i) a linearization of the ozone chemistry, (ii) the stratospheric chemical mechanism of the Model of Ozone and Related Chemical Tracers, version 3, (MOZART-3) and (iii) the relaxation to climatology as implemented in the Transport Model, version 5, (TM5). The IFS uses the latter two schemes by means of a two-way coupled system. Without assimilation, the forecasts showed model-specific shortcomings in predicting start time, extent and duration of the ozone hole. The assimilation of satellite observations from the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a significant improvement of the forecasts when compared with total columns and vertical profiles from ozone sondes. The combined assimilation of observations from multiple instruments helped to overcome limitations of the ultraviolet (UV) sensors at low solar elevation over Antarctica. The assimilation of data from MLS was crucial to obtain a good agreement with the observed ozone profiles both in the polar stratosphere and troposphere. The ozone analyses by the three model configurations were very similar despite the different underlying chemistry schemes. Using ozone analyses as initial conditions had a very beneficial but variable effect on the predictability of the ozone hole over 15 days. The

  6. Polar stratospheric clouds and ozone depletion

    Science.gov (United States)

    Toon, Owen B.; Turco, Richard P.

    1991-01-01

    A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. Approximately 70 percent of the ozone above Antarctica, which equals about 3 percent of the earth's ozone, is lost during September and October. Various hypotheses for ozone depletion are discussed including the theory suggesting that chlorine compounds might be responsible for the ozone hole, whereby chlorine enters the atmosphere as a component of chlorofluorocarbons produced by humans. The three types of PSCs, nitric acid trihydrate, slowly cooling water-ice, and rapidly cooling water-ice clouds act as important components of the Antarctic ozone depletion. It is indicated that destruction of the ozone will be more severe each year for the next few decades, leading to a doubling in area of the Antarctic ozone hole.

  7. Vertical Distribution and Variability of Ozone During July 1999 Over Andenes, Norway

    Science.gov (United States)

    Schmidlin, F. J.; Northam, E. T.; Ross, E. D.; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    Ozonesonde measurements of the polar atmosphere obtained at Andenes, Norway during July 1999 showed unusual characteristics when compared with mid- or low-latitude ozone profiles. A minimum of two ozonesondes each day were released, one in late afternoon and one in early evening. A very well-defined ledge in the ozone profile corresponding to the tropopause appears to form as a result of transport. The ozone amount increases four to five times, from about 30 nb at the tropopause to 120 nb at a pressure about 10-20 hPa lower. The typical peak ozone value, although at a higher altitude than the ledge, appears at a much lower pressure (approx. 140 hPa) than found in midor low-latitudes (approx. 18-25 hPa), Total column ozone amounts are consistently higher than 300 DU. Analysis of the variation with regard to wind conditions will be discussed.

  8. I Situ Stratospheric Ozone Measurements.

    Science.gov (United States)

    Dessler, Andrew Emory

    In situ measurements of stratospheric ozone have been made from both balloon and ER-2 aircraft platforms. The ozone instrument uses the absorption of 253.7-nm radiation to measure ozone with a total uncertainty of +/- 5% (including statistical and systematic errors). During March 1992, a balloon gondola was flown to 30 km over Greenland to investigate the chemistry of inorganic chlorine. Simultaneous measurements of ozone, ClO, and NO are used to test our knowledge of the partitioning of the Cl_{rm y} and NO_{rm y} families. Analysis of these profiles demonstrates the importance for the chemistry of the stratosphere of heterogeneous chemistry on sulfate aerosol surfaces. A year later, a similar ozone instrument flew on the ER-2 as part of the Central Equatorial Pacific EXperiment (CEPEX) from Nadi, Fiji. Using a simple photochemical -dynamical model employing climatological cloud cover, we are able to reproduce our ozone measurements, which supports the view that the concentration of ozone in the tropical lower stratosphere is controlled by production and transport, with chemical loss playing an insignificant role. Finally, four mid-latitude ozone profiles obtained during the summers of 1987, 1988, and 1989 are presented. Comparisons with Stratospheric Aerosol and Gas Experiment II (SAGE II) ozone data show that, between 25 and 37 km, SAGE II ozone is ~10% higher than the Harvard ozone profiles. Statistical analyses indicate that this is a systematic difference that cannot be explained by atmospheric or instrumental variability. This work also shows that zonal averages of satellite and in situ instruments can be effectively compared when atmospheric flow is predominantly zonal.

  9. Climate Prediction Center (CPC)Stratospheric Monitoring Ozone Blended Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 3-D global ozone mixing ratio (ppm) and total column ozone (DU) dataset analyzed from daily Solar Backscatter Ultraviolet Instrument(SBUV/2) and TIROS Operational...

  10. Instrumentation on commercial aircraft for monitoring the atmospheric composition on a global scale: the IAGOS system, technical overview of ozone and carbon monoxide measurements

    Directory of Open Access Journals (Sweden)

    Phillipe Nédélec

    2015-06-01

    Full Text Available This article presents the In-service Aircraft of a Global Observing System (IAGOS developed for operations on commercial long-range Airbus aircraft (A330/A340 for monitoring the atmospheric composition. IAGOS is the continuation of the former Measurement of OZone and water vapour on Airbus In-service airCraft (MOZAIC programme (1994–2014 with five aircraft operated by European airlines over 20 yr. MOZAIC has provided unique scientific database used worldwide by the scientific community. In continuation of MOZAIC, IAGOS aims to equip a fleet up to 20 aircraft around the world and for operations over decades. IAGOS started in July 2011 with the first instruments installed aboard a Lufthansa A340-300, and a total of six aircraft are already in operation. We present the technical aircraft system concept, with basic instruments for O3, CO, water vapour and clouds; and optional instruments for measuring either NOy, NOx, aerosols or CO2/CH4. In this article, we focus on the O3 and CO instrumentation while other measurements are or will be described in specific papers. O3 and CO are measured by optimised but well-known methods such as UV absorption and IR correlation, respectively. We describe the data processing/validation and the data quality control for O3 and CO. Using the first two overlapping years of MOZAIC/IAGOS, we conclude that IAGOS can be considered as the continuation of MOZAIC with the same data quality of O3 and CO measurements.

  11. Interactive Ozone and Methane Chemistry in GISS-E2 Historical and Future Climate Simulations

    Science.gov (United States)

    Shindell, D. T.; Pechony, O.; Voulgarakis, A.; Faluvegi, G.; Nazarenko. L.; Lamarque, J.-F.; Bowman, K.; Milly, G.; Kovari, B.; Ruedy, R.; hide

    2013-01-01

    The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the largescale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF) calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016W/sq. m. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18W/ sq. m higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in a slightly stronger

  12. Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2013-03-01

    Full Text Available The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in

  13. Elevated atmospheric CO2 increases water use efficiency in Florida scrub oak

    Science.gov (United States)

    Drake, B. G.; Hayek, L. C.; Johnson, D. P.; Li, J.; Powell, T. L.

    2009-12-01

    Plants are expected to have higher rates of photosynthesis and reduced transpiration as atmospheric CO2 (Ca) continues to rise. But will higher Ca reduce water loss, and increase water use efficiency and soil water in native ecosystems? We tested this question using large (3.0m by 2.8m) open top chambers to expose Florida scrub oak on Merritt Island Wildlife Refuge, Kennedy Space Center, FL, from May 1996 to June 2007 to elevated levels of atmospheric CO2, (Ce = Ca + 350ppm) compared to ambient Ca. Although Ce stimulated total shoot biomass 68% by the end of the study, the effect of Ce on annual growth declined each year (Seiler et al. 2009, Global Change Biology15, 356-367). Compared with the effects of Ca, Ce increased net ecosystem CO2 exchange approximately 70% on average for the entire study, increased leaf area index (LAI) seasonally, reduced evapotranspiration except during mid-summer of some years, and, depending on the relative effect of Ce on LAI, increased volumetric soil water content.. These results are consistent with the observation that continental river discharge has increased as Ca has risen throughout the past 50 years (Gedney et al., Nature, Vol. 439, 16 February 2006).

  14. Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability

    Directory of Open Access Journals (Sweden)

    B. Hassler

    2014-05-01

    Full Text Available Peak stratospheric chlorofluorocarbon (CFC and other ozone depleting substance (ODS concentrations were reached in the mid- to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP/World Meteorological Organization (WMO Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument. Archive location information for each data set is also given.

  15. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge.

    Science.gov (United States)

    Jones, M L M; Hodges, G; Mills, G

    2010-02-01

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha(-1) yr(-1). Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. Evaluating trends in tropospheric ozone observations from TES with sonde data for the period 2005-2010

    Science.gov (United States)

    Verstraeten, W. W.; Zörner, J.; Boersma, K. F.

    2012-04-01

    Tropospheric ozone is a global air pollutant and an important greenhouse gas. It is mainly produced by the photochemical reaction of short wave radiation with precursor molecules such as NOx and VOC's originating from anthropogenic pollution and biogenic sources. Besides that, intrusions of stratospheric ozone into the higher troposphere contribute to the ozone abundance in the lower atmosphere. Balloon soundings are one way of measuring ozone. These sondes provide in situ measurements of temperature, pressure, humidity and ozone from balloons launched from stations located all over the world. As the distribution of ozone in the troposphere is not uniform both temporal as well as spatial variability in ozone concentrations must be considered. In contrast to the poor spatial sampling by sondes, spaceborne sensors provide a much better coverage and a fixed time retrieval of ozone enabling the understanding of patterns and origins of tropospheric ozone. These sensors, for instance TES (Tropospheric Emission Spectrometer onboard NASA's EOS-Aura satellite), however need to be evaluated with independent data, such as worldwide sonde ozone data (i.e. World Ozone and Ultraviolet Data Center, WOUDC). The objective of this study is to investigate any tropospheric ozone trends when evaluating the TES v4 data record with the worldwide WOUDC sonde dataset for the period 2005-2010. A comparison between the TES and the WOUDC data provides a detailed consistency check of the ozone spatial distribution as well as the seasonal and multi-year patterns in TES and sonde ozone. We used a maximum range of 300 km and a maximum time difference of ± 9 hours between the version 4 TES and sonde ozone data as coincidence criteria to increase the probability that the same air parcels are sampled. To ensure a valid comparison, the TES averaging kernel was applied on the sonde data. Validation of TES tropospheric ozone is conducted at the lower (surface - 500 hPa) and upper (> 500 h

  17. Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

    Science.gov (United States)

    Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

    2010-05-01

    Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivumplant species. The μ-value increase was lower for microorganisms growing on yeast extract then for those growing on glucose, i.e. the effect of elevated CO2 was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). After adding glucose, enzyme activities under elevated CO2 were 1.2-1.9-fold higher than under ambient CO2. This indicates the increased activity of microorganisms, which leads to accelerated C turnover in soil under elevated CO2. Our results clearly showed that the functional characteristics of the soil microbial community (i

  18. The influence of temperature on ozone production under varying NOx conditions - a modelling study

    Science.gov (United States)

    Coates, Jane; Mar, Kathleen A.; Ojha, Narendra; Butler, Tim M.

    2016-09-01

    Surface ozone is a secondary air pollutant produced during the atmospheric photochemical degradation of emitted volatile organic compounds (VOCs) in the presence of sunlight and nitrogen oxides (NOx). Temperature directly influences ozone production through speeding up the rates of chemical reactions and increasing the emissions of VOCs, such as isoprene, from vegetation. In this study, we used an idealised box model with different chemical mechanisms (Master Chemical Mechanism, MCMv3.2; Common Representative Intermediates, CRIv2; Model for OZone and Related Chemical Tracers, MOZART-4; Regional Acid Deposition Model, RADM2; Carbon Bond Mechanism, CB05) to examine the non-linear relationship between ozone, NOx and temperature, and we compared this to previous observational studies. Under high-NOx conditions, an increase in ozone from 20 to 40 °C of up to 20 ppbv was due to faster reaction rates, while increased isoprene emissions added up to a further 11 ppbv of ozone. The largest inter-mechanism differences were obtained at high temperatures and high-NOx emissions. CB05 and RADM2 simulated more NOx-sensitive chemistry than MCMv3.2, CRIv2 and MOZART-4, which could lead to different mitigation strategies being proposed depending on the chemical mechanism. The increased oxidation rate of emitted VOC with temperature controlled the rate of Ox production; the net influence of peroxy nitrates increased net Ox production per molecule of emitted VOC oxidised. The rate of increase in ozone mixing ratios with temperature from our box model simulations was about half the rate of increase in ozone with temperature observed over central Europe or simulated by a regional chemistry transport model. Modifying the box model set-up to approximate stagnant meteorological conditions increased the rate of increase of ozone with temperature as the accumulation of oxidants enhanced ozone production through the increased production of peroxy radicals from the secondary degradation of

  19. Atmospheric evidence for a global secular increase in isotopic discrimination of land photosynthesis

    Science.gov (United States)

    Keeling, R. F.; Graven, H. D.; Welp, L.; Piper, S. C.; Bollenbacher, A.; Resplandy, L.; Meijer, H. A. J.

    2016-12-01

    A decrease in the 13C/12C ratio of atmospheric CO2 owing to the addition of fossil-fuel derived CO2, known as the 13C-Suess effect, has been documented by direct observations since 1977 and from ice-core measurements since the industrial revolution. Measurements of this decrease have previously been used to constrain land and ocean carbon sinks. Here we show, however, that no plausible combination of land and ocean sinks can explain the 13C/12C decrease unless an increase has occurred in the isotopic discrimination of land photosynthesis, i.e. the tendency of land plants to preferentially assimilate 12CO2 compared to 13CO2. A trend toward greater discrimination at higher CO2 levels is broadly consistent with geological evidence for the response of C3 plants at times of altered atmospheric CO2 as well as with tree-ring studies over the past century. The discrimination trend will be discussed in the context of theories for optimal stomatal behavior under changing atmospheric CO2.

  20. Elevated Atmospheric CO2 Affects Ectomycorrhizal Species Abundance and Increases Sporocarp Production under Field Conditions

    Directory of Open Access Journals (Sweden)

    Douglas L. Godbold

    2015-04-01

    Full Text Available Anthropogenic activities during the last century have increased levels of atmospheric CO2. Forest net primary productivity increases in response to elevated CO2, altering the quantity and quality of carbon supplied to the rhizosphere. Ectomycorrhizal fungi form obligate symbiotic associations with the fine roots of trees that mediate improved scavenging for nutrients in exchange for a carbohydrate supply. Understanding how the community structure of ectomycorrhizal fungi is altered by climate change is important to further our understanding of ecosystem function. Betula pendula and Fagus sylvatica were grown in an elevated CO2 atmosphere delivered using free air carbon dioxide enrichment (FACE under field conditions in the U.K., and Picea abies was grown under elevated CO2 in glass domes in the Czech Republic. We used morphotyping and sequencing of the internal transcribed spacer region of the fungal ribosomal operon to study ectomycorrhizal community structure. Under FACE, un-colonised roots tips increased in abundance for Fagus sylvatica, and during 2006, sporocarp biomass of Peziza badia significantly increased. In domes, ectomycorrhizal community composition shifted from short-distance and smooth medium-distance to contact exploration types. Supply and competition for carbon belowground can influence ectomycorrhizal community structure with the potential to alter ecosystem function.

  1. Chemistry and Dynamics of the Unusual 2015 Antarctic Ozone Hole

    Science.gov (United States)

    Braathen, Geir O.

    2016-04-01

    The Global Atmosphere Watch of the World Meteorological Organization includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the unusually large ozone hole of 2015 will be compared to ozone holes from 2003 to 2014 and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone hole on record. On the other hand, the ozone holes of 2004, 2007, 2010 and 2012, 2013 and 2014 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The South Polar vortex of 2015 was unusually stable and long-lived, so ozone depletion lasted longer than seen in recent years. The ozone hole area, i.e. the area where total ozone is less that 220 DU, averaged over the worst 60 consecutive days was larger in 2015 than in any other year since the beginning of the ozone hole era in the early 1980s.

  2. Link between Antarctic ozone depletion and summer warming over southern Africa

    Science.gov (United States)

    Manatsa, Desmond; Morioka, Yushi; Behera, Swadhin K.; Yamagata, Toshi; Matarira, Caxton H.

    2013-11-01

    The notable rise in surface air temperatures over southern Africa over the past two decades is thought to largely result from the human-induced increase in atmospheric greenhouse gas concentrations. In addition, the loss of stratospheric ozone over Antarctica is thought to have had a significant impact on tropospheric circulation, and hence climate, in the Southern Hemisphere summer, by favouring the positive phase of the Southern Annular Mode. Here, we use reanalysis data to compare the climate of southern Africa before and after the development of the large ozone hole, and investigate possible links between the development of the Antarctic ozone hole and summer warming in the region, defining 1970-1993 as the pre-ozone hole era, and 1993-2011 as the large ozone hole era. We find that the ozone-induced shift in the polarity of the Southern Annular Mode after 1993 coincided with an intensification of the Angola Low, a continental low pressure system that normally develops in austral summer and is mostly located over Angola. We show that the deepening of this low pressure system, in turn, was associated with an increase in the flux of warm surface air from the lower latitudes to southern Africa. We suggest that the recent summer warming over southern Africa is linked to these shifts in atmospheric circulation that are probably induced by Antarctic ozone loss.

  3. Kudzu (Pueraria montana) Invasion Doubles Emissions of Nitric Oxide, a Precursor to Tropospheric Ozone.

    Science.gov (United States)

    Hickman, J. E.; Wu, S.; Mickley, L. J.; Lerdau, M. T.

    2008-12-01

    Nitrogen-fixing plants can increase rates of nitrogen (N) cycling in soils, fluxes of the greenhouse gas nitrous oxide (N2O), and fluxes of the ozone precursor nitric oxide (NO). Invasion by the nitrogen-fixing legume kudzu (Pueraria montana) across millions of hectares in the southeastern United States could be contributing to increased ozone concentrations. Ozone formation in the Southeast is broadly limited by atmospheric NO concentrations, so perturbations to the N cycle by kudzu have the potential to increase ozone concentrations in the region. At three sites in Madison County, Georgia, kudzu invasion increased rates of net N mineralization by up to an order of magnitude and rates of net nitrification and soil pools of NO3- and NO2- by up to 500%. Emissions of NO from soils invaded by kudzu averaged 2.81 ng NO-N cm-2 h-1, significantly higher than emissions from soil dominated by native vegetation, which averaged 1.24 ng NO-N cm-2 h-1. Emissions of N2O display a trend towards increasing under kudzu invasion, but N2O emissions at these sites were three orders of magnitude smaller than emissions of NO. Atmospheric chemical modeling suggests that these higher NO emissions could increase ozone concentrations in the region by up to 2 ppb. We propose that kudzu invasion in the southeastern United States represents a novel threat to air quality and could increase the frequency with which federal ozone standards are exceeded.

  4. Applications of ozone therapy in dentistry

    National Research Council Canada - National Science Library

    Shiva Gupta; D Deepa

    2016-01-01

    .... In the present era of increasing antibiotic resistance, ozone therapy is an alternative medical treatment that rationales to increase the amount of oxygen to the body through institution of ozone into the body...

  5. Increased incidence of still birth in piglets associated with levels of atmospheric carbon monoxide.

    Science.gov (United States)

    Wood, E N

    1979-03-31

    Raised levels of atmospheric carbon monoxide, associated with malfunctioning gas-fired creep heaters and inadequate ventilation, appeared responsible for an increased incidence of stillbirths in two herds. In one, a concentration of 180 to 200 ppm of carbon monoxide was readily produced. Both problems resolved when the ventilation and heating were improved, the incidence of stillbirths in one herd falling from 28 to 6.7 per cent. It is suggested that similar incidents may have occurred during cold weather but have been ascribed to other causes.

  6. Increased incidence of still birth in piglets associated with high levels of atmospheric carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Wood, E.N.

    1979-03-31

    Raised levels of atmospheric carbon monoxide, associated with malfunctioning gas-fired creep heaters and inadequate ventilation, appeared responsible for an increased incidence of stillbirths in two herds. In one, a concentration of 180 to 200 ppm of carbon monoxide was readily produced. Both problems resolved when the ventilation and heating were improved, the incidence of stillbirths in one herd falling from 28 to 6.7%. It is suggested that similar incidents may have occurred during cold weather but have been ascribed to other causes. 5 references, 1 table.

  7. Increased litterfall in tropical forests boosts the transfer of soil CO2 to the atmosphere.

    Directory of Open Access Journals (Sweden)

    Emma J Sayer

    Full Text Available Aboveground litter production in forests is likely to increase as a consequence of elevated atmospheric carbon dioxide (CO(2 concentrations, rising temperatures, and shifting rainfall patterns. As litterfall represents a major flux of carbon from vegetation to soil, changes in litter inputs are likely to have wide-reaching consequences for soil carbon dynamics. Such disturbances to the carbon balance may be particularly important in the tropics because tropical forests store almost 30% of the global soil carbon, making them a critical component of the global carbon cycle; nevertheless, the effects of increasing aboveground litter production on belowground carbon dynamics are poorly understood. We used long-term, large-scale monthly litter removal and addition treatments in a lowland tropical forest to assess the consequences of increased litterfall on belowground CO(2 production. Over the second to the fifth year of treatments, litter addition increased soil respiration more than litter removal decreased it; soil respiration was on average 20% lower in the litter removal and 43% higher in the litter addition treatment compared to the controls but litter addition did not change microbial biomass. We predicted a 9% increase in soil respiration in the litter addition plots, based on the 20% decrease in the litter removal plots and an 11% reduction due to lower fine root biomass in the litter addition plots. The 43% measured increase in soil respiration was therefore 34% higher than predicted and it is possible that this 'extra' CO(2 was a result of priming effects, i.e. stimulation of the decomposition of older soil organic matter by the addition of fresh organic matter. Our results show that increases in aboveground litter production as a result of global change have the potential to cause considerable losses of soil carbon to the atmosphere in tropical forests.

  8. Dobson spectrophotometer ozone measurements during international ozone rocketsonde intercomparison

    Science.gov (United States)

    Parsons, C. L.

    1980-01-01

    Measurements of the total ozone content of the atmosphere, made with seven ground based instruments at a site near Wallops Island, Virginia, are discussed in terms for serving as control values with which the rocketborne sensor data products can be compared. These products are profiles of O3 concentration with altitude. By integrating over the range of altitudes from the surface to the rocket apogee and by appropriately estimating the residual ozone amount from apogee to the top of the atmosphere, a total ozone amount can be computed from the profiles that can be directly compared with the ground based instrumentation results. Dobson spectrophotometers were used for two of the ground-based instruments. Preliminary data collected during the IORI from Dobson spectrophotometers 72 and 38 are presented. The agreement between the two and the variability of total ozone overburden through the experiment period are discussed.

  9. Increasing synoptic scale variability in atmospheric CO2 at Hateruma Island associated with increasing East-Asian emissions

    Directory of Open Access Journals (Sweden)

    S. Hashimoto

    2010-01-01

    Full Text Available In-situ observations of atmospheric CO2 and CH4 at Hateruma Island (24.05° N, 123.80° E, 47 m a.s.l, Japan shows large synoptic scale variations during a 6-month period from November to April, when the sampled air is predominantly of continental origin due to the Asian winter monsoon. Synoptic scale variations are extracted from the daily averaged values for the years between 1996 and 2007, along with the annual standard deviations (σCO2 and σCH4 for CO2 and CH4, respectively for the relevant 6-month period. During this 6-month period the absolute mixing ratios of CO2 and CH4 at Hateruma are also elevated compared to those at two sites in the central North Pacific Ocean. The temporal change in σCO2 shows a systematic increase over the 12-year period, with elevated excursions in 1998 and 2003; there is no clear increase in σCH4. We also find that the σCO2/σCH4 ratio increases gradually from 1996 to 2002 and rapidly after 2002 without any extreme deviations that characterised σCO2. The σCO2/σCH4 ratio correlates closely with the recent rapid increase in fossil carbon emissions from China, as indicated in the Carbon Dioxide Information Analysis Center (CDIAC database. This methodology can be applied to multiple chemical tracers of sufficient lifetime, for tracking overall changes in regional emissions.

  10. Multiple scattering calculation of the middle ultraviolet reaching the ground. [SST effects on ozone layer

    Science.gov (United States)

    Shettle, E. P.; Green, A. E. S.

    1974-01-01

    An investigation is conducted regarding the increase in the UV radiation as a function of wavelength due to changes in the amounts of ozone and various other parameters affecting the radiation in the atmosphere. Attention is given to the methods that can be used to solve the problem of the transfer of radiation through an absorbing and scattering atmosphere which includes aerosols. The multiple channel solution reported by Mudgett and Richards' (1971) is extended to vertically inhomogeneous atmospheres.

  11. Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude

    Science.gov (United States)

    Zeng, Ning; Zhao, Fang; Collatz, George J.; Kalnay, Eugenia; Salawitch, Ross J.; West, Tristram O.; Guanter, Luis

    2014-11-01

    The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 25° N and 60° N and the high-latitude natural vegetation between 50° N and 70° N. The long-term trend of seasonal amplitude increase is 0.311 +/- 0.027 per cent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001-2010 than in 1961

  12. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

    Directory of Open Access Journals (Sweden)

    Roshan GholamReza

    2012-12-01

    Full Text Available Abstract The rapid rise of Caspian Sea water level (about 2.25 meters since 1978 has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006 and future (2025-2100 time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3. The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21. The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82 between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  13. Diagnosing changes in European tropospheric ozone: A model study of past and future changes

    Science.gov (United States)

    Tummon, Fiona; Revell, Laura; Stenke, Andrea; Staehelin, Johannes; Peter, Thomas

    2016-04-01

    In recent decades, the negative impacts of tropospheric ozone on human and ecosystem health have led to policy changes aimed at reducing emissions of ozone precursor gases such as nitrogen oxides (NOx) and carbon monoxide (CO). Although emissions of these species have significantly decreased in Europe and North America since the early 1990s, observational data indicate that free tropospheric ozone over Europe has not decreased as expected. Uncertainty remains as to how much of a role the transport of stratospheric ozone or tropospheric ozone from remote source regions has played in recent trends, as well as to how this will evolve in a changing climate. The global chemistry-climate model SOCOL (SOlar Chemistry Ozone Links) is used to investigate tropospheric ozone over Europe from 1960 to 2100. To fully disentangle the effects of both long-range transport and input from the stratosphere, simulations are run with ozone tracers from 21 different atmospheric regions. In addition to a standard reference run, several sensitivity simulations are run: one with emissions of NOx and CO held constant at 1960 levels, one with methane (CH4) held at constant 1960 levels (in addition to the NOx and CO), and a third with NOx and CO emissions from Asia fixed at 1960 levels. Results suggest that the largest contributions to European tropospheric ozone originate from the tropical and northern mid-latitude boundary layer and free troposphere. Contributions from these regions increase over the historical period (1960-2010), indicating that changes in source gas emissions have affected ozone concentrations in the European free troposphere most strongly. Contributions from these regions then decrease from 2010-2100, but remain considerably larger than input from the stratosphere, which is relatively small in all simulations throughout the entire simulated period (1960-2100). The stratospheric contribution does, however, increase slightly over the 21st century, in tandem with ozone

  14. Distribution ozone concentration in Klang Valley using GIS approaches

    Science.gov (United States)

    Sulaiman, A.; Rahman, A. A. Ab; Maulud, K. N. Abdul; Latif, M. T.; Ahmad, F.; Wahid, M. A. Abdul; Ibrahim, M. A.; Halim, N. D. Abdul

    2017-05-01

    Today, ozone has become one of the main air pollutants in Malaysia. The high ozone precursor concentrations have been encouraging the ozone production. The development of the Klang Valley, Malaysia has many types of physical activities such as urban commercial, industrial area, settlement area and others, which has increased the risk of atmospheric pollution. The purpose of this paper is to determine the spatial distribution between types of land use and ozone concentration that are occurred in the year 2014. The study areas for this paper include Shah Alam, Kajang, Petaling Jaya and Port Klang. Distribution of ozone concentration will be showed via spatial analysis tools in Geographic Information Systems (GIS) approached and the types of land use will be extracted using Remote Sensing technique. The result showed 97 ppb (parts-per-billion, 10-9) and 161 ppb recorded at Port Klang and Shah Alam respectively that are mainly represented by the settlement area. Therefore, the physical land use need to be monitor and controlled by the government in order to make sure the ozone production for daily per hour will not exceed the regulation allowed.

  15. Faster turnover of new soil carbon inputs under increased atmospheric CO2.

    Science.gov (United States)

    van Groenigen, Kees Jan; Osenberg, Craig W; Terrer, César; Carrillo, Yolima; Dijkstra, Feike A; Heath, James; Nie, Ming; Pendall, Elise; Phillips, Richard P; Hungate, Bruce A

    2017-10-01

    Rising levels of atmospheric CO2 frequently stimulate plant inputs to soil, but the consequences of these changes for soil carbon (C) dynamics are poorly understood. Plant-derived inputs can accumulate in the soil and become part of the soil C pool ("new soil C"), or accelerate losses of pre-existing ("old") soil C. The dynamics of the new and old pools will likely differ and alter the long-term fate of soil C, but these separate pools, which can be distinguished through isotopic labeling, have not been considered in past syntheses. Using meta-analysis, we found that while elevated CO2 (ranging from 550 to 800 parts per million by volume) stimulates the accumulation of new soil C in the short term (soil C pool over either temporal scale. Our results are inconsistent with predictions of conventional soil C models and suggest that elevated CO2 might increase turnover rates of new soil C. Because increased turnover rates of new soil C limit the potential for additional soil C sequestration, the capacity of land ecosystems to slow the rise in atmospheric CO2 concentrations may be smaller than previously assumed. © 2017 John Wiley & Sons Ltd.

  16. The sensitivity of stratospheric ozone changes through the 21st century to N2O and CH4

    Directory of Open Access Journals (Sweden)

    B. E. Williamson

    2012-12-01

    Full Text Available Through the 21st century, anthropogenic emissions of the greenhouse gases N2O and CH4 are projected to increase, thus increasing their atmospheric concentrations. Consequently, reactive nitrogen species produced from N2O and reactive hydrogen species produced from CH4 are expected to play an increasingly important role in determining stratospheric ozone concentrations. Eight chemistry-climate model simulations were performed to assess the sensitivity of stratospheric ozone to different emissions scenarios for N2O and CH4. Global-mean total column ozone increases through the 21st century in all eight simulations as a result of CO2-induced stratospheric cooling and decreasing stratospheric halogen concentrations. Larger N2O concentrations were associated with smaller ozone increases, due to reactive nitrogen-mediated ozone destruction. In the simulation with the largest N2O increase, global-mean total column ozone increased by 4.3 DU through the 21st century, compared with 10.0 DU in the simulation with the smallest N2O increase. In contrast, larger CH4 concentrations were associated with larger ozone increases; global-mean total column ozone increased by 16.7 DU through the 21st century in the simulation with the largest CH4 concentrations and by 4.4 DU in the simulation with the lowest CH4 concentrations. CH4 leads to ozone loss in the upper and lower stratosphere by increasing the rate of reactive hydrogen-mediated ozone loss cycles, however in the lower stratosphere and troposphere, CH4 leads to ozone increases due to photochemical smog-type chemistry. In addition to this mechanism, total column ozone increases due to H2O-induced cooling of the stratosphere, and slowing of the chlorine-catalyzed ozone loss cycles due to an increased rate of the CH4 + Cl reaction. Stratospheric column ozone through the 21st century exhibits a near-linear response to changes in N2O and CH4 surface concentrations, which provides a simple parameterization for the

  17. NOAA JPSS Ozone Mapping and Profiler Suite (OMPS) Nadir Total Column Sensor Data Record (SDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ozone Mapping and Profiler Suite (OMPS) onboard the Suomi NPP satellite monitors ozone from space. OMPS will collect total column and vertical profile ozone data...

  18. NOAA JPSS Ozone Mapping and Profiler Suite (OMPS) Nadir Profile Science Sensor Data Record (SDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ozone Mapping and Profiler Suite (OMPS) onboard the Suomi-NPP satellite monitors ozone from space. OMPS will collect total column and vertical profile ozone data...

  19. Comparative study of ozonized olive oil and ozonized sunflower oil

    OpenAIRE

    Díaz,Maritza F.; Hernández,Rebeca; Martínez,Goitybell; Vidal,Genny; Gómez,Magali; Fernández,Harold; Garcés,Rafael

    2006-01-01

    In this study the ozonized olive and sunflower oils are chemical and microbiologically compared. These oils were introduced into a reactor with bubbling ozone gas in a water bath at room temperature until they were solidified. The peroxide, acidity and iodine values along with antimicrobial activity were determined. Ozonization effects on the fatty acid composition of these oils were analyzed using Gas-Liquid Chromatographic Technique. An increase in peroxidation and acidity values was observ...

  20. Elevated CO2 and/or ozone modify lignification in the wood of poplars (Populus tremula x alba).

    Science.gov (United States)

    Richet, Nicolas; Afif, Dany; Tozo, Koffi; Pollet, Brigitte; Maillard, Pascale; Huber, Françoise; Priault, Pierrick; Banvoy, Jacques; Gross, Patrick; Dizengremel, Pierre; Lapierre, Catherine; Perré, Patrick; Cabané, Mireille

    2012-06-01

    Trees will have to cope with increasing levels of CO(2) and ozone in the atmosphere. The purpose of this work was to assess whether the lignification process could be altered in the wood of poplars under elevated CO(2) and/or ozone. Young poplars were exposed either to charcoal-filtered air (control), to elevated CO(2) (800 μl l(-1)), to ozone (200 nl l(-1)) or to a combination of elevated CO(2) and ozone in controlled chambers. Lignification was analysed at different levels: biosynthesis pathway activities (enzyme and transcript), lignin content, and capacity to incorporate new assimilates by using (13)C labelling. Elevated CO(2) and ozone had opposite effects on many parameters (growth, biomass, cambial activity, wood cell wall thickness) except on lignin content which was increased by elevated CO(2) and/or ozone. However, this increased lignification was due to different response mechanisms. Under elevated CO(2), carbon supply to the stem and effective lignin synthesis were enhanced, leading to increased lignin content, although there was a reduction in the level of some enzyme and transcript involved in the lignin pathway. Ozone treatment induced a reduction in carbon supply and effective lignin synthesis as well as transcripts from all steps of the lignin pathway and some corresponding enzyme activities. However, lignin content was increased under ozone probably due to variations in other major components of the cell wall. Both mechanisms seemed to coexist under combined treatment and resulted in a high increase in lignin content.

  1. Urban tropospheric ozone increases the prevalence of vitamin D deficiency among Belgian postmenopausal women with outdoor activities during summer.

    Science.gov (United States)

    Manicourt, Daniel-Henri; Devogelaer, Jean-Pierre

    2008-10-01

    By absorbing sunlight UVB and thereby reducing cutaneous vitamin D photosynthesis, ozone, a common urban pollutant, could cause hypovitaminosis D. The objective of the study was to establish the characteristics and percentage of subjects with serum 25-hydroxyvitamin D [25(OH)D] less than 75 nmol/liter among postmenopausal women engaging in outdoor activities in either Brussels or the countryside. This was a cross-sectional study conducted in a university research hospital. Among 249 women consulting for either shoulder tendonitis or lumbar spine osteoarthritis, 121 free of conditions and drugs affecting bone and calcium metabolism completed two food-frequency questionnaires within 15 d and we selected the 85 subjects with retest scores within the +/- 15% of test scores. Other parameters included sun exposure index (SEI), PTH levels, and femoral neck T-score. Urban residents (n = 38) and rural residents (n = 47) did not differ in mean ages, body mass indices, and vitamin D intakes. When compared with rural inhabitants, urban inhabitants were exposed to ozone levels 3 times higher, and despite a higher mean SEI (113 vs. 87; P < 0.001), they had a higher prevalence of 25(OH)D less than 75 nmol/liter (84 vs. 38%). After adjusting for SEI, 25(OH)D was 2-fold higher in rural residents, and after adjusting for 25(OH)D, SEI was 3-fold higher in urban residents. Femoral neck T-scores correlated positively with 25(OH)D and negatively with PTH levels. Air pollution may be a neglected risk factor for hypovitaminosis D, which is known to compromise several health outcomes. As long as 25(OH)D is greater than 75 nmol/liter, calcium intakes greater than 17.5 mmol/d are unnecessary to prevent elevations in PTH levels.

  2. Source attribution of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  3. Chlorofluoromethanes in the stratosphere and some possible consequences for ozone

    Science.gov (United States)

    Turco, R. P.; Whitten, R. C.

    1975-01-01

    Inert chlorofluoromethanes are used by man as refrigerants and aerosol propellants. These substances eventually escape and diffuse upward into the stratosphere. At great enough heights, UV sunlight can photodissociate these chlorofluorocarbons into chlorine atoms which will catalytically destroy ozone molecules. Chlorofluoromethane production has been increasing steadily in recent years to its present level of about a megaton per year, and chlorofluorocarbon usage will probably continue to grow in the future. Calculations with a one-dimensional time-dependent atmospheric model suggests that, if projected increases in chlorofluoromethane use materialize and there is no tropospheric destruction mechanism for these gases, the total global abundance of ozone may be reduced by more than 20 per cent over the next 50 years. If the residence times for these fluorocarbons in the troposphere are in the range of 10-30 years, however, predicted ozone depletions would be significantly smaller.

  4. 1,2-Dichlorohexafluoro-Cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E) and (Z) stereoisomers

    Science.gov (United States)

    Papadimitriou, Vassileios C.; McGillen, Max R.; Smith, Shona C.; Jubb, Aaron M.; Portmann, Robert W.; Hall, Bradley D.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

    2013-01-01

    The atmospheric processing of (E)- and (Z)-1,2-dichlorohexafluorocyclobutane (1,2-c-C4F6Cl2, R-316c) was examined in this work as the ozone depleting (ODP) and global warming (GWP) potentials of this proposed replacement compound are presently unknown. The predominant atmospheric loss processes and infrared absorption spectra of the R-316c isomers were measured to provide a basis to evaluate their atmospheric lifetimes and, thus, ODPs and GWPs. UV absorption spectra were measured between 184.95 to 230 nm at temperatures between 214 and 296 K and a parametrization for use in atmospheric modeling is presented. The Cl atom quantum yield in the 193 nm photolysis of R- 316c was measured to be 1.90 +/- 0.27. Hexafluorocyclobutene (c-C4F6) was determined to be a photolysis co-product with molar yields of 0.7 and 1.0 (+/-10%) for (E)- and (Z)-R-316c, respectively. The 296 K total rate coefficient for the O(1D) + R-316c reaction, i.e., O(1D) loss, was measured to be (1.56 +/- 0.11) × 10(exp -10)cu cm/ molecule/s and the reactive rate coefficient, i.e., R-316c loss, was measured to be (1.36 +/- 0.20) × 10(exp -10)cu cm/molecule/s corresponding to a approx. 88% reactive yield. Rate coefficient upper-limits for the OH and O3 reaction with R-316c were determined to be global annually averaged lifetimes for the (E)- and (Z)-R-316c isomers were calculated using a 2-D atmospheric model to be 74.6 +/- 3 and 114.1 +/-10 years, respectively, where the estimated uncertainties are due solely to the uncertainty in the UV absorption spectra. Stratospheric photolysis is the predominant atmospheric loss process for both isomers with the O(1D) reaction making a minor, approx. 2% for the (E) isomer and 7% for the (Z) isomer, contribution to the total atmospheric loss. Ozone depletion potentials for (E)- and (Z)-R-316c were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their

  5. An update on ozone profile trends for the period 2000 to 2016

    Directory of Open Access Journals (Sweden)

    W. Steinbrecht

    2017-09-01

    Full Text Available Ozone profile trends over the period 2000 to 2016 from several merged satellite ozone data sets and from ground-based data measured by four techniques at stations of the Network for the Detection of Atmospheric Composition Change indicate significant ozone increases in the upper stratosphere, between 35 and 48 km altitude (5 and 1 hPa. Near 2 hPa (42 km, ozone has been increasing by about 1.5 % per decade in the tropics (20° S to 20° N, and by 2 to 2.5 % per decade in the 35 to 60° latitude bands of both hemispheres. At levels below 35 km (5 hPa, 2000 to 2016 ozone trends are smaller and not statistically significant. The observed trend profiles are consistent with expectations from chemistry climate model simulations. This study confirms positive trends of upper stratospheric ozone already reported, e.g., in the WMO/UNEP Ozone Assessment 2014 or by Harris et al. (2015. Compared to those studies, three to four additional years of observations, updated and improved data sets with reduced drift, and the fact that nearly all individual data sets indicate ozone increase in the upper stratosphere, all give enhanced confidence. Uncertainties have been reduced, for example for the trend near 2 hPa in the 35 to 60° latitude bands from about ±5 % (2σ in Harris et al. (2015 to less than ±2 % (2σ. Nevertheless, a thorough analysis of possible drifts and differences between various data sources is still required, as is a detailed attribution of the observed increases to declining ozone-depleting substances and to stratospheric cooling. Ongoing quality observations from multiple independent platforms are key for verifying that recovery of the ozone layer continues as expected.

  6. Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites

    Science.gov (United States)

    José-mathieu Koné, Yéfanlan; Vieira Borges, Alberto

    2017-04-01

    Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites. Y J M Koné (1) & A.V. Borges (2) (1) Centre de recherches océanologiques (CRO) d'Abidjan, (Ivory Coast) (2) University of Liège, Chemical Oceanography Unit, Liège, Belgium (Belgium) Eutrophication is a worldwide environmental problem and a definitive solution is far from being achieved, despite the large number of studies documenting its causes. In small aquatic ecosystems, excessive growth of macrophytes is a well known undesirable consequence of eutrophication. When these plants die and sink to the bottom the decomposing biomass depletes oxygen content in the water column thus leading to anoxia promoting methane (CH4) production. Here, we reported the CH4 data obtained during six campaigns covering the annual cycle in two small lagoons of Ivory Coast (Ono, Kodjoboué) that are contrasted in the degree of eutrophication and the corresponding coverage of macrophytes (e.g. Echinochloa pyramidalis, Eichhornia crassipes, Hydrilla verticillata). Our data showed a high spatio-temporal variability of CH4 within the lagoons and between the two systems, with CH4 concentrations in surface waters ranging between 80 to 74,604 nmol L-1. The highest CH4 concentration values were observed in the eutrophic Ono lagoon that is covered by 80% of macrophytes, suggesting that lagoons dominated by macrophytes are significant sources of CH4 toward the atmosphere.

  7. Convective forcing of mercury and ozone in the Arctic boundary layer induced by leads in sea ice

    Science.gov (United States)

    Moore, Christopher W.; Obrist, Daniel; Steffen, Alexandra; Staebler, Ralf M.; Douglas, Thomas A.; Richter, Andreas; Nghiem, Son V.

    2014-02-01

    The ongoing regime shift of Arctic sea ice from perennial to seasonal ice is associated with more dynamic patterns of opening and closing sea-ice leads (large transient channels of open water in the ice), which may affect atmospheric and biogeochemical cycles in the Arctic. Mercury and ozone are rapidly removed from the atmospheric boundary layer during depletion events in the Arctic, caused by destruction of ozone along with oxidation of gaseous elemental mercury (Hg(0)) to oxidized mercury (Hg(II)) in the atmosphere and its subsequent deposition to snow and ice. Ozone depletion events can change the oxidative capacity of the air by affecting atmospheric hydroxyl radical chemistry, whereas atmospheric mercury depletion events can increase the deposition of mercury to the Arctic, some of which can enter ecosystems during snowmelt. Here we present near-surface measurements of atmospheric mercury and ozone from two Arctic field campaigns near Barrow, Alaska. We find that coastal depletion events are directly linked to sea-ice dynamics. A consolidated ice cover facilitates the depletion of Hg(0) and ozone, but these immediately recover to near-background concentrations in the upwind presence of open sea-ice leads. We attribute the rapid recoveries of Hg(0) and ozone to lead-initiated shallow convection in the stable Arctic boundary layer, which mixes Hg(0) and ozone from undepleted air masses aloft. This convective forcing provides additional Hg(0) to the surface layer at a time of active depletion chemistry, where it is subject to renewed oxidation. Future work will need to establish the degree to which large-scale changes in sea-ice dynamics across the Arctic alter ozone chemistry and mercury deposition in fragile Arctic ecosystems.

  8. Analysis of Ozone in Cloudy Versus Clear Sky Conditions

    Science.gov (United States)

    Strode, Sarah; Douglass, Anne; Ziemke, Jerald

    2016-01-01

    Convection impacts ozone concentrations by transporting ozone vertically and by lofting ozone precursors from the surface, while the clouds and lighting associated with convection affect ozone chemistry. Observations of the above-cloud ozone column (Ziemke et al., 2009) derived from the OMI instrument show geographic variability, and comparison of the above-cloud ozone with all-sky tropospheric ozone columns from OMI indicates important regional differences. We use two global models of atmospheric chemistry, the GMI chemical transport model (CTM) and the GEOS-5 chemistry climate model, to diagnose the contributions of transport and chemistry to observed differences in ozone between areas with and without deep convection, as well as differences in clean versus polluted convective regions. We also investigate how the above-cloud tropospheric ozone from OMI can provide constraints on the relationship between ozone and convection in a free-running climate simulation as well as a CTM.

  9. A case of nighttime high ozone concentration over the greater Athens area

    Energy Technology Data Exchange (ETDEWEB)

    Mavrakis, Anastasios [Dept. of Economic and Regional Dept., Panteion Univ., Athens (Greece); Flocas, Helena A.; Mavromatidis, Elias; Kallos, George; Theoharatos, George [Dept. of Environmental Physics and Meteorology, Univ. of Athens (Greece); Christides, Anastasios [Bureau of Pollution Control and Environmental Quality of the Dept. Association of Thriassion Plain, Elefsis (Greece)

    2010-02-15

    A case of abrupt and significant increase of surface ozone was examined, which is recorded during the night of October 9{sup th}, 2003, over the arca of the Thriassion Plain - Greece, being accompanied by the occurrence of a wind outbreak during the same period. As this increase cannot be explained by the ordinary diurnal evolution of tropospheric ozone concentration, the possibility of downward stratospheric ozone transport was investigated. It was indeed found that the case is associated with tropopause folding and subsequent stratospheric air intrusion in the upper troposphere over Greece. With the aid of mesoscale modeling, being also supported by the hydraulic theory, it was found that the intense wind outbreak is associated with the development of disturbances in the lee side of the neighbouring mountain ranges. These disturbances contribute to the free troposphere - atmospheric boundary layer interaction, facilitating the transportation of stratospheric air close to the surface, thus resulting to the observed tropospheric ozone increase. (orig.)

  10. Elevated CO2 and ozone reduce nitrogen acquisition by Pinus halepensis from its mycorrhizal symbiont.

    Science.gov (United States)

    Kytöviita, Minna-Maarit; Le Thiec, Didier; Dizengremel, Pierre

    2001-03-01

    The effects of 700 µmol mol-1 CO2 and 200 nmol mol-1 ozone on photosynthesis in Pinus halepensis seedlings and on N translocation from its mycorrhizal symbiont, Paxillus involutus, were studied under nutrient-poor conditions. After 79 days of exposure, ozone reduced and elevated CO2 increased net assimilation rate. However, the effect was dependent on daily accumulated exposure. No statistically significant differences in total plant mass accumulation were observed, although ozone-treated plants tended to be smaller. Changes in atmospheric gas concentrations induced changes in allocation of resources: under elevated ozone, shoots showed high priority over roots and had significantly elevated N concentrations. As a result of different shoot N concentration and net carbon assimilation rates, photosynthetic N use efficiency was significantly increased under elevated CO2 and decreased under ozone. The differences in photosynthesis were mirrored in the growth of the fungus in symbiosis with the pine seedlings. However, exposure to CO2 and ozone both reduced the symbiosis-mediated N uptake. The results suggest an increased carbon cost of symbiosis-mediated N uptake under elevated CO2, while under ozone, plant N acquisition is preferentially shifted towards increased root uptake.

  11. Application of atmospheric pressure plasma on polyethylene for increased prosthesis adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Van Vrekhem, S., E-mail: stijn.vanvrekhem@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Cools, P. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Declercq, H. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Tissue Engineering Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185 6B3, 9000 Ghent (Belgium); Van Tongel, A. [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185 13K12, 9000 Ghent (Belgium); Vercruysse, C.; Cornelissen, M. [Tissue Engineering Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185 6B3, 9000 Ghent (Belgium); De Geyter, N.; Morent, R. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium)

    2015-12-01

    Biopolymers are often subjected to surface modification in order to improve their surface characteristics. The goal of this study is to show the use of plasma technology to enhance the adhesion of ultra-high molecular weight polyethylene (UHMWPE) shoulder prostheses. Two different plasma techniques (low pressure plasma activation and atmospheric pressure plasma polymerization) are performed on UHMWPE to increase the adhesion between (1) the polymer and polymethylmethacrylate (PMMA) bone cement and (2) the polymer and osteoblast cells. Both techniques are performed using a dielectric barrier discharge (DBD). A previous paper showed that low pressure plasma activation of UHMWPE results in the incorporation of oxygen-containing functional groups, which leads to an increased surface wettability. Atmospheric pressure plasma polymerization of methylmethacrylate (MMA) on UHMWPE results in a PMMA-like coating, which could be deposited with a high degree of control of chemical composition and layer thickness. The thin film also proved to be relatively stable upon incubation in a phosphate buffer solution (PBS). This paper discusses the next stage of the study, which includes testing the adhesion of the plasma-activated and plasma-polymerized samples to bone cement through pull-out tests and testing the cell adhesion and proliferation on the samples. In order to perform the pull-out tests, all samples were cut to standard dimensions and fixed in bone cement in a reproducible way with a sample holder specially designed for this purpose. The cell adhesion and proliferation were tested by means of an MTS assay and live/dead staining after culturing MC3T3 osteoblast cells on UHMWPE samples. The results show that both plasma activation and plasma polymerization significantly improve the adhesion to bone cement and enhance cell adhesion and proliferation. In conclusion, it can be stated that the use of plasma technology can lead to an implant with improved quality and a subsequent

  12. Tropical circulation and precipitation response to ozone depletion and recovery

    Science.gov (United States)

    Brönnimann, Stefan; Jacques-Coper, Martín; Rozanov, Eugene; Fischer, Andreas M.; Morgenstern, Olaf; Zeng, Guang; Akiyoshi, Hideharu; Yamashita, Yousuke

    2017-06-01

    Among the few well established changes in atmospheric circulation in recent decades are those caused by stratospheric ozone depletion. They include a strengthening and poleward contraction of the westerly atmospheric circulation over the Southern extratropics, i.e. a strengthening Southern Annular Mode (SAM), in austral spring and summer. Associated effects on extratropical temperature and precipitation and more recently subtropical precipitation have been documented and are understood in a zonal mean framework. We present zonally asymmetric effects of ozone depletion that reach into the tropics and affect atmospheric circulation and precipitation, including the South Pacific Convergence Zone (SPCZ), the most important rainband of the Southern Hemisphere. Using observation-based analyses and model simulations we show that over the 1961-1996 period, ozone depletion led to increased precipitation at the northern flank of the SPCZ and to decreased precipitation to the south. The effects originate from a flow pattern over the southwestern Pacific that extends equatorward and alters the propagation of synoptic waves and thus the position of the SPCZ. Model simulations suggest that anticipated stratospheric ozone recovery over the next decades will reverse these effects.

  13. Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games.

    Science.gov (United States)

    Gao, Yi; Zhang, Meigen

    2012-01-01

    The regional air quality modeling system RAMS (regional atmospheric modeling system)-CMAQ (community multi-scale air quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008. Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind, temperature and ozone, but NOx concentration is overestimated. Although ozone concentration decreased during Olympics, high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 microg/m3 at Aoyuncun site, respectively. The analysis of sensitive test, with and without emission controls, shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning. The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate. Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August, horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer. On 24 July, as the wind velocity was smaller, the impact of transport on the rural place was not obvious.

  14. Ozone trends at northern mid- and high latitudes – a European perspective

    Directory of Open Access Journals (Sweden)

    N. R. P. Harris

    2008-05-01

    Full Text Available The EU CANDIDOZ project investigated the chemical and dynamical influences on decadal ozone trends focusing on the Northern Hemisphere. High quality long-term ozone data sets, satellite-based as well as ground-based, and the long-term meteorological reanalyses from ECMWF and NCEP are used together with advanced multiple regression models and atmospheric models to assess the relative roles of chemistry and transport in stratospheric ozone changes. This overall synthesis of the individual analyses in CANDIDOZ shows clearly one common feature in the NH mid latitudes and in the Arctic: an almost monotonic negative trend from the late 1970s to the mid 1990s followed by an increase. In most trend studies, the Equivalent Effective Stratospheric Chlorine (EESC which peaked in 1997 as a consequence of the Montreal Protocol was observed to describe ozone loss better than a simple linear trend. Furthermore, all individual analyses point to changes in dynamical drivers, such as the residual circulation (responsible for the meridional transport of ozone into middle and high latitudes playing a key role in the observed turnaround. The changes in ozone transport are associated with variations in polar chemical ozone loss via heterogeneous ozone chemistry on PSCs (polar stratospheric clouds. Synoptic scale processes as represented by the new equivalent latitude proxy, by conventional tropopause altitude or by 250 hPa geopotential height have also been successfully linked to the recent ozone increases in the lowermost stratosphere. These show significant regional variation with a large impact over Europe and seem to be linked to changes in tropospheric climate patterns such as the North Atlantic Oscillation. Some influence in recent ozone increases was also attributed to the rise in solar cycle number 23. Changes from the late 1970s to the mid 1990s were found in a number of characteristics of the Arctic vortex. However, only one trend was found when more recent

  15. Ozone depletion update.

    Science.gov (United States)

    Coldiron, B M

    1996-03-01

    Stratospheric ozone depletion due to chlorofluorocarbons an d increased ultraviolet radiation penetration has long been predicted. To determine if predictions of ozone depletion are correct and, if so, the significance of this depletion. Review of the English literature regarding ozone depletion and solar ultraviolet radiation. The ozone layer is showing definite thinning. Recently, significantly increased ultraviolet radiation transmission has been detected at ground level at several metering stations. It appears that man-made aerosols (air pollution) block increased UVB transmission in urban areas. Recent satellite measurements of stratospheric fluorine levels more directly implicate chlorofluorocarbons as a major source of catalytic stratospheric chlorine, although natural sources may account for up to 40% of stratospheric chlorine. Stratospheric chlorine concentrations, and resultant increased ozone destruction, will be enhanced for at least the next 70 years. The potential for increased transmission of ultraviolet radiation will exist for the next several hundred years. While little damage due to increased ultraviolet radiation has occurred so far, the potential for long-term problems is great.

  16. Applications of ozone therapy in dentistry

    OpenAIRE

    Shiva Gupta; Deepa, D.

    2016-01-01

    Ozone is an allotropic form of oxygen, which is effectively used in the treatment of different diseases for more than 100 years. In the present era of increasing antibiotic resistance, ozone therapy is an alternative medical treatment that rationales to increase the amount of oxygen to the body through institution of ozone into the body. Owing to its beneficial biological properties including antimicrobial and immune-stimulating effects, ozone therapy has opened new vistas in treatment modali...

  17. The predicted impact of VOCs from Marijuana cultivation operations on ozone concentrations in great Denver, CO.

    Science.gov (United States)

    Wang, C. T.; Vizuete, W.; Wiedinmyer, C.; Ashworth, K.

    2016-12-01

    Colorado is the first the marijuana legal states in the United States since 2014. As a result, thousands of legal Marijuana cultivation operations are at great Denver area now. Those Marijuana cultivation operations could be the potential to release a lot of biogenic VOCs, such as monoterpene(C10H16), alpha-pinene, and D-limonene. Those alkene species could rapidly increase the peroxy radicals and chemical reactions in the atmosphere, especially in the urban area which belong to VOC-limited ozone regime. These emissions will increase the ozone in Denver city, where is ozone non-attainment area. Some previous research explained the marijuana smoke and indoor air quality (Martyny, Serrano, Schaeffer, & Van Dyke, 2013) and the smell of marijuana chemical compounds(Rice & Koziel, 2015). However, there have been no studies discuss on identifying and assessing emission rate from marijuana and how those species impact on atmospheric chemistry and ozone concentration, and the marijuana emissions have been not considered in the national emission inventory, either. This research will use air quality model to identify the possibility of ozone impact by marijuana cultivation emission. The Comprehensive Air Quality Model with Extensions, CAMx, are applied for this research to identify the impact of ozone concentration. This model is government regulatory model based on the Three-State Air Quality Modeling Study (3SAQS), which developed by UNC-Chapel Hill and ENVIRON in 2012. This model is used for evaluation and regulate the ozone impact in ozone non-attainment area, Denver city. The details of the 3SAQS model setup and protocol can be found in the 3SAQS report(UNC-IE, 2013). For the marijuana emission study scenarios, we assumed the monoterpene (C10H16) is the only emission species in air quality model and identify the ozone change in the model by the different quantity of emission rate from marijuana cultivation operations.

  18. Modeling of regional climate change effects on ground-level ozone and childhood asthma.

    Science.gov (United States)

    Sheffield, Perry E; Knowlton, Kim; Carr, Jessie L; Kinney, Patrick L

    2011-09-01

    The adverse respiratory effects of ground-level ozone are well established. Ozone is the air pollutant most consistently projected to increase under future climate change. To project future pediatric asthma emergency department visits associated with ground-level ozone changes, comparing 1990s to 2020s. This study assessed future numbers of asthma emergency department visits for children aged 0-17 years using (1) baseline New York City metropolitan area emergency department rates; (2) a dose-response relationship between ozone levels and pediatric asthma emergency department visits; and (3) projected daily 8-hour maximum ozone concentrations for the 2020s as simulated by a global-to-regional climate change and atmospheric chemistry model. Sensitivity analyses included population projections and ozone precursor changes. This analysis occurred in 2010. In this model, climate change could cause an increase in regional summer ozone-related asthma emergency department visits for children aged 0-17 years of 7.3% across the New York City metropolitan region by the 2020s. This effect diminished with inclusion of ozone precursor changes. When population growth is included, the projections of morbidity related to ozone are even larger. The results of this analysis demonstrate that the use of regional climate and atmospheric chemistry models make possible the projection of local climate change health effects for specific age groups and specific disease outcomes, such as emergency department visits for asthma. Efforts should be made to improve on this type of modeling to inform local and wider-scale climate change mitigation and adaptation policy. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  19. An Atlantic streamer in stratospheric ozone observations and SD-WACCM simulation data

    Science.gov (United States)

    Hocke, Klemens; Schranz, Franziska; Maillard Barras, Eliane; Moreira, Lorena; Kämpfer, Niklaus

    2017-03-01

    Observation and simulation of individual ozone streamers are important for the description and understanding of non-linear transport processes in the middle atmosphere. A sudden increase in mid-stratospheric ozone occurred above central Europe on 4 December 2015. The GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) and the Stratospheric Ozone MOnitoring RAdiometer (SOMORA) in Switzerland measured an ozone enhancement of about 30 % at 34 km altitude (8.3 hPa) from 1 to 4 December. A similar ozone increase is simulated by the Specified Dynamics Whole Atmosphere Community Climate (SD-WACCM) model. Further, the global ozone fields at 34 km altitude (8.3 hPa) from SD-WACCM and the satellite experiment Aura/MLS show a remarkable agreement for the location and timing of an ozone streamer (large-scale tongue-like structure) extending from the subtropics in northern America over the Atlantic to central Europe. This agreement indicates that SD-WACCM can inform us about the wind inside the Atlantic ozone streamer. SD-WACCM shows an eastward wind of about 100 m s-1 inside the Atlantic streamer in the mid-stratosphere. SD-WACCM shows that the Atlantic streamer flows along the edge of the polar vortex. The Atlantic streamer turns southward at an erosion region of the polar vortex located above the Caspian Sea. The spatial distribution of stratospheric water vapour indicates a filament outgoing from this erosion region. The Atlantic streamer, the polar vortex erosion region and the water vapour filament belong to the process of planetary wave breaking in the so-called surf zone of the northern midlatitude winter stratosphere.

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

    Science.gov (United States)

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

    2017-08-01

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

  1. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    Science.gov (United States)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2015-08-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

  2. Decreasing, not increasing, leaf area will raise crop yields under global atmospheric change.

    Science.gov (United States)

    Srinivasan, Venkatraman; Kumar, Praveen; Long, Stephen P

    2017-04-01

    Without new innovations, present rates of increase in yields of food crops globally are inadequate to meet the projected rising food demand for 2050 and beyond. A prevailing response of crops to rising [CO2 ] is an increase in leaf area. This is especially marked in soybean, the world's fourth largest food crop in terms of seed production, and the most important vegetable protein source. Is this increase in leaf area beneficial, with respect to increasing yield, or is it detrimental? It is shown from theory and experiment using open-air whole-season elevation of atmospheric [CO2 ] that it is detrimental not only under future conditions of elevated [CO2 ] but also under today's [CO2 ]. A mechanistic biophysical and biochemical model of canopy carbon exchange and microclimate (MLCan) was parameterized for a modern US Midwest soybean cultivar. Model simulations showed that soybean crops grown under current and elevated (550 [ppm]) [CO2 ] overinvest in leaves, and this is predicted to decrease productivity and seed yield 8% and 10%, respectively. This prediction was tested in replicated field trials in which a proportion of emerging leaves was removed prior to expansion, so lowering investment in leaves. The experiment was conducted under open-air conditions for current and future elevated [CO2 ] within the Soybean Free Air Concentration Enrichment facility (SoyFACE) in central Illinois. This treatment resulted in a statistically significant 8% yield increase. This is the first direct proof that a modern crop cultivar produces more leaf than is optimal for yield under today's and future [CO2 ] and that reducing leaf area would give higher yields. Breeding or bioengineering for lower leaf area could, therefore, contribute very significantly to meeting future demand for staple food crops given that an 8% yield increase across the USA alone would amount to 6.5 million metric tons annually. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  3. Impact of climate change on ozone-related mortality and morbidity in Europe.

    Science.gov (United States)

    Orru, Hans; Andersson, Camilla; Ebi, Kristie L; Langner, Joakim; Aström, Christofer; Forsberg, Bertil

    2013-02-01

    Ozone is a highly oxidative pollutant formed from precursors in the presence of sunlight, associated with respiratory morbidity and mortality. All else being equal, concentrations of ground-level ozone are expected to increase due to climate change. Ozone-related health impacts under a changing climate are projected using emission scenarios, models and epidemiological data. European ozone concentrations are modelled with the model of atmospheric transport and chemistry (MATCH)-RCA3 (50×50 km). Projections from two climate models, ECHAM4 and HadCM3, are applied under greenhouse gas emission scenarios A2 and A1B, respectively. We applied a European-wide exposure-response function to gridded population data and country-specific baseline mortality and morbidity. Comparing the current situation (1990-2009) with the baseline period (1961-1990), the largest increase in ozone-associated mortality and morbidity due to climate change (4-5%) have occurred in Belgium, Ireland, the Netherlands and the UK. Comparing the baseline period and the future periods (2021-2050 and 2041-2060), much larger increases in ozone-related mortality and morbidity are projected for Belgium, France, Spain and Portugal, with the impact being stronger using the climate projection from ECHAM4 (A2). However, in Nordic and Baltic countries the same magnitude of decrease is projected. The current study suggests that projected effects of climate change on ozone concentrations could differentially influence mortality and morbidity across Europe.

  4. Increased Growth Factors Play a Role in Wound Healing Promoted by Noninvasive Oxygen-Ozone Therapy in Diabetic Patients with Foot Ulcers

    OpenAIRE

    Jing Zhang; Meiping Guan; Cuihua Xie; Xiangrong Luo; Qian Zhang; Yaoming Xue

    2014-01-01

    Management of diabetic foot ulcers (DFUs) is a great challenge for clinicians. Although the oxygen-ozone treatment improves the diabetic outcome, there are few clinical trials to verify the efficacy and illuminate the underlying mechanisms of oxygen-ozone treatment on DFUs. In the present study, a total of 50 type 2 diabetic patients complicated with DFUs, Wagner stage 2~4, were randomized into control group treated by standard therapy only and ozone group treated by standard therapy plus oxy...

  5. TROPOMI on the ESA Sentinel-5 Precursor: A GMES mission for global observations of the atmospheric composition for climate, air quality and ozone layer applications

    NARCIS (Netherlands)

    Veefkind, J.P.; Aben, I.; McMullan, K.; Förster, H.; Vries, J. de; Otter, G.; Claas, J.; Eskes, H.J.; Haan, J.F. de; Kleipool, Q.; Weele, M. van; Hasekamp, O.; Hoogeveen, R.; Landgraf, J.; Snel, R.; Tol, P.; Ingmann, P.; Voors, R.; Kruizinga, B.; Vink, R.; Visser, H.; Levelt, P.F.

    2012-01-01

    The ESA (European Space Agency) Sentinel-5 Precursor (S-5 P) is a low Earth orbit polar satellite to provide information and services on air quality, climate and the ozone layer in the timeframe 2015-2022. The S-5 P mission is part of the Global Monitoring of the Environment and Security (GMES)

  6. Nobel prize awarded to pioneers in ozone research

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This article details the achievements of the three individuals who shared the 1995 Nobel Prize in Chemistry - Paul Crutzen, Mario Molina, and F. Sherwood Rowland - for their work in atmospheric chemistry, particularly the chemical processes that deplete the ozone layer. Background information about the ozone layer is presented as well as highlights of the ozone research done by the prize winners.

  7. Budget of tropospheric ozone during TOPSE from two chemical transport models

    Science.gov (United States)

    Emmons, L. K.; Hess, P.; Klonecki, A.; Tie, X.; Horowitz, L.; Lamarque, J.-F.; Kinnison, D.; Brasseur, G.; Atlas, E.; Browell, E.; Cantrell, C.; Eisele, F.; Mauldin, R. L.; Merrill, J.; Ridley, B.; Shetter, R.

    2003-04-01

    The tropospheric ozone budget during the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign has been studied using two chemical transport models (CTMs): HANK and the Model of Ozone and Related chemical Tracers, version 2 (MOZART-2). The two models have similar chemical schemes but use different meteorological fields, with HANK using MM5 (Pennsylvania State University, National Center for Atmospheric Research Mesoscale Modeling System) and MOZART-2 driven by European Centre for Medium-Range Weather Forecasts (ECMWF) fields. Both models simulate ozone in good agreement with the observations but underestimate NOx. The models indicate that in the troposphere, averaged over the northern middle and high latitudes, chemical production of ozone drives the increase of ozone seen in the spring. Both ozone gross chemical production and loss increase greatly over the spring months. The in situ production is much larger than the net stratospheric input, and the deposition and horizontal fluxes are relatively small in comparison to chemical destruction. The net production depends sensitively on the concentrations of H2O, HO2 and NO, which differ slightly in the two models. Both models underestimate the chemical production calculated in a steady state model using TOPSE measurements, but the chemical loss rates agree well. Measures of the stratospheric influence on tropospheric ozone in relation to in situ ozone production are discussed. Two different estimates of the stratospheric fraction of O3 in the Northern Hemisphere troposphere indicate it decreases from 30-50% in February to 15-30% in June. A sensitivity study of the effect of a perturbation in the vertical flux on tropospheric ozone indicates the contribution from the stratosphere is approximately 15%.

  8. Ultraviolet radiation in the Arctic - The impact of potential ozone depletions and cloud effects

    Science.gov (United States)

    Tsay, Si-Chee; Stamnes, Knut

    1992-01-01

    The combined effects of ozone depletions/redistributions and particulate clouds on atmospheric cheating/photolysis rates and UV radiation reaching the biosphere are investigated by means of an atmospheric radiation model. Consideration is given to four types of particulate clouds prevalent in the summertime Arctic: stratospheric aerosols, tropospheric aerosols (Arctic haze), cirrus clouds, and stratus clouds. The effects of ozone depletion and vertical redistributions of ozone are also examined. Stratus clouds are found to provide significant protection from UV radiation exposure, but while stratospheric aerosols imply increased UVB exposure, Arctic haze results in a decrease. A redistribution of ozone from the stratosphere to the troposphere tends to decrease UV exposure, but for low solar elevations an increase may occur. A 20-percent ozone depletion leads to about 0.4 K/d cooling in the lower stratosphere, while redistribution of ozone from the stratosphere to the troposphere implies a warming of about 0.015 K/d in the upper troposphere.

  9. Response of the Atlantic Thermohaline Circulation to Increased Atmospheric CO2 in a Coupled Model.

    Science.gov (United States)

    Hu, Aixue; Meehl, Gerald A.; Washington, Warren M.; Dai, Aiguo

    2004-11-01

    Changes in the thermohaline circulation (THC) due to increased CO2 are important in future climate regimes. Using a coupled climate model, the Parallel Climate Model (PCM), regional responses of the THC in the North Atlantic to increased CO2 and the underlying physical processes are studied here. The Atlantic THC shows a 20-yr cycle in the control run, qualitatively agreeing with other modeling results. Compared with the control run, the simulated maximum of the Atlantic THC weakens by about 5 Sv (1 Sv 106 m3 s-1) or 14% in an ensemble of transient experiments with a 1% CO2 increase per year at the time of CO2 doubling. The weakening of the THC is accompanied by reduced poleward heat transport in the midlatitude North Atlantic. Analyses show that oceanic deep convective activity strengthens significantly in the Greenland Iceland Norway (GIN) Seas owing to a saltier (denser) upper ocean, but weakens in the Labrador Sea due to a fresher (lighter) upper ocean and in the south of the Denmark Strait region (SDSR) because of surface warming. The saltiness of the GIN Seas are mainly caused by an increased salty North Atlantic inflow, and reduced sea ice volume fluxes from the Arctic into this region. The warmer SDSR is induced by a reduced heat loss to the atmosphere, and a reduced sea ice flux into this region, resulting in less heat being used to melt ice. Thus, sea ice related salinity effects appear to be more important in the GIN Seas, but sea ice melt-related thermal effects seem to be more important in the SDSR region. On the other hand, the fresher Labrador Sea is mainly attributed to increased precipitation. These regional changes produce the overall weakening of the THC in the Labrador Sea and SDSR, and more vigorous ocean overturning in the GIN Seas. The northward heat transport south of 60°N is reduced with increased CO2, but increased north of 60°N due to the increased flow of North Atlantic water across this latitude.

  10. Ozone Pollution

    Science.gov (United States)

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  11. An Investigation of Polar Ozone Recovery in the 1997 Southern Hemisphere Spring

    Science.gov (United States)

    Pierson, J. M.; Douglass, A. R.; Kawa, S. R.; Newman, P. A.

    2000-01-01

    A chemical transport model is used to investigate the processes that control the depth and duration of the ozone 'hole' in the lower stratosphere through comparisons of model output with measurements from the Total Ozone Mapping Spectrometer (TOMS) and from the Microwave Limb Sounder (MLS) and Halogen Occultation Experiment (HALOE), both on the Upper Atmosphere Research Satellite (UARS). This study extends previous model comparisons with observations into October and November and examine levels in (greater than 31 hPa) and above (less than 31 hPa) the chemical loss region. Averages of column ozone in the model decrease through mid-October below 31 hPa but begin to increase in mid-September above 31 hPa. An investigation of model-tracer data comparisons and other meteorological parameters indicate that the model presents a consistent picture of top-down recovery and tracer transport. An O03budget study at 500 K (below 31 hPa) and 840 K (above 31 hPa) is carried out to investigate the processes that control the timing of the transition of ozone from a chemical to dynamically driven regime. The model ozone decrease at 500 K is due to chemical loss in August and September but is due to upward motion in October. The ozone increase at 840 K is primarily due to photochemical production, with a smaller contribution from transport. These results show that chemistry and dynamics can play different roles in polar vortex ozone recovery at different levels.

  12. Validation of OSIRIS Ozone Inversions

    Science.gov (United States)

    Gudnason, P.; Evans, W. F.; von Savigny, C.; Sioris, C.; Halley, C.; Degenstein, D.; Llewellyn, E. J.; Petelina, S.; Gattinger, R. L.; Odin Team

    2002-12-01

    The OSIRIS instrument onboard the Odin satellite, that was launched on February 20, 2001, is a combined optical spectrograph and infrared imager that obtains profil sets of atmospheric spectra from 280 to 800 nm when Odin scans the terrestrial limb. It has been possible to make a preliminary analysis of the ozone profiles using the Chappuis absorption feature. Three algorithms have been developed for ozone profile inversions from these limb spectra sets. We have dubbed these the Gattinger, Von Savigny-Flittner and DOAS methods. These are being evaluated against POAM and other satellite data. Based on performance, one of these will be selected for the operational algorithm. The infrared imager data have been used by Degenstein with the tomographic inversion procedure to derive ozone concentrations above 60 km. This paper will present some of these initial observations and indicate the best algorithm potential of OSIRIS to make spectacular advances in the study of terrestrial ozone.

  13. Ozone Layer Research and Technical Resources

    Science.gov (United States)

    Access information on research and technical resources related to ozone layer science. This page provides links to research efforts led by organizations such as the National Oceanic and Atmospheric Administration, the United Nations Environment Program, an

  14. Fast Flow Cavity Enhanced Ozone Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Naturally occurring in the stratosphere, ozone plays a significant role in many atmospheric reactions, cloud formation, and is the key player in shielding harmful UV...

  15. Atmospheric Nitrogen Deposition: An increasingly Important Source of "new" Nitrogen Supporting Coastal Eutrophication

    Science.gov (United States)

    Paerl, H. W.; Whitall, D. R.; Dennis, R. L.

    2004-12-01

    Atmospheric deposition of nitrogen (AD-N) to the North Atlantic Ocean (NAO) basin arises from diverse pollution sources in North America and Western Europe; these sources have increased by 5 to10 fold since the Industrial Revolution, agricultural expansion and urbanization in the NAO airshed and continue to increase in both geographic and depositional magnitudes. Based on recent estimates, AD-N flux (11.2 Tg N per year) accounts for 46-57 per cent of the total new or externally-supplied anthropogenic N flux to the NAO. In US estuarine and coastal waters, from 10 to over 40 per cent of new N loading is attributed to AD-N; estimates for North Carolina's Albemarle-Pamlico Sound system range from 20 to over 30 per cent. In developing regions of the world, AD-N is one of the most rapidly expanding sources of new N. AD-N has been linked to eutrophication in N-sensitive coastal waters. In North Carolina, N deposition has increased since the 1960's as a result of urbanization (chiefly NOx) and more recently agricultural growth (NH4+ and organic N). In particular, rapidly-expanding livestock operations have led to increases in the generation of N-enriched wastes and manures; a substantial proportion (30- >70 per cent) of which may be emitted as NH3 gas. Recent growth and intensification of animal operations in the midwest and coastal regions (e.g., Mid-Atlantic coastal plain) have been linked to increasing amounts of NH4+ deposition, according to a 2 decadal analysis of the National Acid Deposition Program (NADP) network. The impacts of both increasing amounts and altered chemical composition of AD-N are being examined in the N-limited, eutrophying (i.e., expanding algal blooms, hypoxia and anoxia) Neuse River Estuary, Pamlico Sound and coastal waters of North Carolina. Because of its relatively large contribution to total new N loading and potential biogeochemical and ecological importance in N sensitive waters, AD-N requires attention from air/watershed nutrient budgeting

  16. Increased growth factors play a role in wound healing promoted by noninvasive oxygen-ozone therapy in diabetic patients with foot ulcers.

    Science.gov (United States)

    Zhang, Jing; Guan, Meiping; Xie, Cuihua; Luo, Xiangrong; Zhang, Qian; Xue, Yaoming

    2014-01-01

    Management of diabetic foot ulcers (DFUs) is a great challenge for clinicians. Although the oxygen-ozone treatment improves the diabetic outcome, there are few clinical trials to verify the efficacy and illuminate the underlying mechanisms of oxygen-ozone treatment on DFUs. In the present study, a total of 50 type 2 diabetic patients complicated with DFUs, Wagner stage 2~4, were randomized into control group treated by standard therapy only and ozone group treated by standard therapy plus oxygen-ozone treatment. The therapeutic effects were graded into 4 levels from grade 0 (no change) to grade 3 (wound healing). The wound sizes were measured at baseline and day 20, respectively. Tissue biopsies were performed at baseline and day 11. The expressions of vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), and platelet-derived growth factor (PDGF) proteins in the pathologic specimens were determined by immunohistochemical examinations. The effective rate of ozone group was significantly higher than that of control group (92% versus 64%, P ozone group than in control group (P ozone group than in control group. Ozone therapy promotes the wound healing of DFUs via potential induction of VEGF, TGF-β, and PDGF at early stage of the treatment. (Clinical trial registry number is ChiCTR-TRC-14004415).

  17. Measurements and Mesoscale Modeling of Autumnal Vertical Ozone Profiles in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Yen-Ping Peng

    2008-01-01

    Full Text Available Vertical measurements of ozone were made using a tethered balloon at the Linyuan site in Kaohsiung County, southern Taiwan. Ozone was monitored at altitudes of 0, 100, 300, 500, and 1000 m from November 23 to 25 in 2005. The potential temperature profiles revealed a stable atmosphere during the study period, largely because of the dominance of the high-pressure system and nocturnal radiation cooling close to the surface. The mixing height was low (50 - 300 m, particularly in the late night and early morning. The surface ozone concentrations that were predicted using TAPM (The Air Pollution Model were high (33.7 - 119 ppbv in the daytime (10:00 - 16:00 and were low (10 - 40 ppbv at other times; the predictions of which were consistent with the observations. The simulated surface ozone concentrations reveal that costal lands typically had higher ozone concentrations than those inland, because most industrial parks are located in or close to the boundaries of Kaohsiung City. Both measurements and simulations indicate that daytime ozone concentrations decreased quickly with increasing height at altitudes below 300 m; while nighttime ozone concentrations were lower at low altitudes (50 to 300 m than at higher altitudes, partly because of dry deposition and titration of surface ozone by the near-surface nitrogen oxides (NOx and partly because of the existence of the residual layer above the stable nocturnal boundary layer. The simulations show a good correlation between the maximum daytime surface ozone concentration and average nighttime ozone concentration above the nocturnal boundary layer.

  18. Increasing atmospheric CO2 overrides the historical legacy of multiple stable biome states in Africa.

    Science.gov (United States)

    Moncrieff, Glenn R; Scheiter, Simon; Bond, William J; Higgins, Steven I

    2014-02-01

    The dominant vegetation over much of the global land surface is not predetermined by contemporary climate, but also influenced by past environmental conditions. This confounds attempts to predict current and future biome distributions, because even a perfect model would project multiple possible biomes without knowledge of the historical vegetation state. Here we compare the distribution of tree- and grass-dominated biomes across Africa simulated using a dynamic global vegetation model (DGVM). We explicitly evaluate where and under what conditions multiple stable biome states are possible for current and projected future climates. Our simulation results show that multiple stable biomes states are possible for vast areas of tropical and subtropical Africa under current conditions. Widespread loss of the potential for multiple stable biomes states is projected in the 21st Century, driven by increasing atmospheric CO2 . Many sites where currently both tree-dominated and grass-dominated biomes are possible become deterministically tree-dominated. Regions with multiple stable biome states are widespread and require consideration when attempting to predict future vegetation changes. Testing for behaviour characteristic of systems with multiple stable equilibria, such as hysteresis and dependence on historical conditions, and the resulting uncertainty in simulated vegetation, will lead to improved projections of global change impacts. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. Radiative impacts of ozone and other radiatively active components

    Energy Technology Data Exchange (ETDEWEB)

    Stordal, F.; Larsen, T.A.; Myhre, G.; Zetterberg, L.

    1996-07-01

    Radiative transfer calculations have been performed with two models of infrared radiation (broad band and line-by-line) and one model for ultraviolet and visible radiation (discrete ordinate method). The calculations are aimed at quantifying the radiative effects of radiatively active gases, in particular ozone. Seasonal variations and trends in the radiative forcing due to presence of ozone in the atmosphere is studied, based on observed ozone profiles from ozone soundings at selected Nordic locations. 15 refs., 28 figs., 8 tabs.

  20. Observations of the Antarctic Ozone Hole from 2003 to 2014

    Science.gov (United States)

    Braathen, Geir O.

    2015-04-01

    The Global Atmosphere Watch of WMO includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the ozone holes from 2003 to 2014 will be compared to each other and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone hole on record. On the other hand, the ozone holes of 2004, 2007, 2010 and 2012 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The ozone hole of 2011 suffered more ozone depletion than in 2010, but it was quite average in comparison to other years of the last decade. The situation was similar in 2013 and 2014. The interannual variability will be discussed with the help of meteorological data, such as temperature conditions, possibility for polar stratospheric clouds, vortex shape and vortex longevity.

  1. The role of ions in particle nucleation under atmospheric conditions

    DEFF Research Database (Denmark)

    Enghoff, Martin B.; Pedersen, J. O. P.; Bondo, T.

    2008-01-01

    Aerosol nucleation has been studied experimentally in purified, atmospheric air, containing trace amounts of water vapor, ozone, and sulfur dioxide. The results are compared with model calculations. It is found that an increase in ionization by a factor of 10 increases the production rate of stable...

  2. Our Changing Atmosphere.

    Science.gov (United States)

    Clearing, 1988

    1988-01-01

    Summarizes what is known about two major variables involved in certain types of chemical pollution that seem to be changing the structure of the Earth's atmosphere. Discusses the greenhouse effect and the ozone layer. (TW)

  3. Reassessment of causes of ozone column variability following the eruption of Mount Pinatubo using a nudged CCM

    Directory of Open Access Journals (Sweden)

    P. Telford

    2009-07-01

    Full Text Available The eruption of Mount Pinatubo produced the largest loading of stratospheric sulphate aerosol in the twentieth century. This heated the tropical lower stratosphere, affecting stratospheric circulation, and provided enhanced surface area for heterogeneous chemistry. These factors combined to produce record low values of "global" total ozone column. Though well studied, there remains some uncertainty about the attribution of this low ozone, with contributions from both chemical and dynamical effects. We take a complementary approach to previous studies, nudging the potential temperature and horizontal winds in the new UKCA chemistry climate model to reproduce the atmospheric response and assess the impact on global total ozone. We then combine model runs and observations to distinguish between chemical and dynamical effects. To estimate the effects of increased heterogeneous chemistry on ozone we compare runs with volcanically enhanced and background surface aerosol density. The modelled depletion of global ozone peaks at about 7 DU in early 1993, in good agreement with values obtained from observations. We subtract the modelled aerosol induced ozone loss from the observed ozone record and attribute the remaining variability to `dynamical' effects. The remaining variability is dominated by the QBO. We also examine tropical and mid-latitude ozone, diagnosing contributions from El Niño in the tropics and identifying dynamically driven low ozone in northern mid-latitudes, which we interpret as possible evidence of changes in the QBO. We conclude that, on a global scale, the record lows of extra-polar ozone are produced by the increased heterogeneous chemistry, although there is evidence for dynamics produced low ozone in certain regions, including northern mid-latitudes.

  4. Impact of lower stratospheric ozone on seasonal prediction systems

    Directory of Open Access Journals (Sweden)

    Kelebogile Mathole

    2014-03-01

    Full Text Available We conducted a comparison of trends in lower stratospheric temperatures and summer zonal wind fields based on 27 years of reanalysis data and output from hindcast simulations using a coupled ocean-atmospheric general circulation model (OAGCM. Lower stratospheric ozone in the OAGCM was relaxed to the observed climatology and increasing greenhouse gas concentrations were neglected. In the reanalysis, lower stratospheric ozone fields were better represented than in the OAGCM. The spring lower stratospheric/ upper tropospheric cooling in the polar cap observed in the reanalysis, which is caused by a direct ozone depletion in the past two decades and is in agreement with previous studies, did not appear in the OAGCM. The corresponding summer tropospheric response also differed between data sets. In the reanalysis, a statistically significant poleward trend of the summer jet position was found, whereas no such trend was found in the OAGCM. Furthermore, the jet position in the reanalysis exhibited larger interannual variability than that in the OAGCM. We conclude that these differences are caused by the absence of long-term lower stratospheric ozone changes in the OAGCM. Improper representation or non-inclusion of such ozone variability in a prediction model could adversely affect the accuracy of the predictability of summer rainfall forecasts over South Africa.

  5. Study nonlinear dynamics of stratospheric ozone concentration at Pakistan Terrestrial region

    Science.gov (United States)

    Jan, Bulbul; Zai, Muhammad Ayub Khan Yousuf; Afradi, Faisal Khan; Aziz, Zohaib

    2018-03-01

    This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmospheric region. Ozone considered now the most important issue in the world because of its diverse effects on earth biosphere, including human health, ecosystem, marine life, agriculture yield and climate change. Therefore, this paper deals with total monthly time series data of stratospheric ozone over the Pakistan atmospheric region from 1970 to 2013. Two approaches, basic statistical analysis and Fractal dimension (D) have adapted to study the nature of nonlinear dynamics of stratospheric ozone level. Results obtained from this research have shown that the Hurst exponent values of both methods of fractal dimension revealed an anti-persistent behavior (negatively correlated), i.e. decreasing trend for all lags and Rescaled range analysis is more appropriate as compared to Detrended fluctuation analysis. For seasonal time series all month follows an anti-persistent behavior except in the month of November which shown persistence behavior i.e. time series is an independent and increasing trend. The normality test statistics also confirmed the nonlinear behavior of ozone and the rejection of hypothesis indicates the strong evidence of the complexity of data. This study will be useful to the researchers working in the same field in the future to verify the complex nature of stratospheric ozone.

  6. Experimental drought in a tropical rain forest increases soil carbon dioxide losses to the atmosphere

    Science.gov (United States)

    Cleveland, Cory C.; Wieder, William R.; Reed, Sasha C.; Townsend, Alan R.

    2010-01-01

    to the atmosphere both via increased soil O2 availability and through responses to elevated DOM concentrations.

  7. Applications of ozone therapy in dentistry

    Directory of Open Access Journals (Sweden)

    Shiva Gupta

    2016-01-01

    Full Text Available Ozone is an allotropic form of oxygen, which is effectively used in the treatment of different diseases for more than 100 years. In the present era of increasing antibiotic resistance, ozone therapy is an alternative medical treatment that rationales to increase the amount of oxygen to the body through institution of ozone into the body. Owing to its beneficial biological properties including antimicrobial and immune-stimulating effects, ozone therapy has opened new vistas in treatment modalities of dental pathologies for patients of all ages. The objective of this article is to review the literature available on applications of ozone in dentistry.

  8. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2007.

    Science.gov (United States)

    2008-01-01

    This year the Montreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.

  9. Recent Biomass Burning in the Tropics and Related Changes in Tropospheric Ozone

    Science.gov (United States)

    Ziemke; Chandra, J. R. S.; Duncan, B. N.; Schoeberl, M. R.; Torres, O.; Damon, M. R.; Bhartia, P. K.

    2009-01-01

    Biomass burning is an important source of chemical precursors of tropospheric ozone. In the tropics, biomass burning produces ozone enhancements over broad regions of Indonesia, Africa, and South America including Brazil. Fires are intentionally set in these regions during the dry season each year to clear cropland and to clear land for human/industrial expansion. In Indonesia enhanced burning occurs during dry El Nino conditions such as in 1997 and 2006. These burning activities cause enhancement in atmospheric particulates and trace gases which are harmful to human health. Measurements from the Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) from October 2004-November 2008 are used to evaluate the effects of biomass burning on tropical tropospheric ozone. These measurements show sizeable decreases approx.15-20% in ozone in Brazil during 2008 compared to 2007 which we attribute to the reduction in biomass burning. Three broad biomass burning regions in the tropics (South America including Brazil, western Africa, and Indonesia) were analyzed in the context of OMI/MLS measurements and the Global Modeling Initiative (GMI) chemical transport model developed at Goddard Space Flight Center. The results indicate that the impact of biomass burning on ozone is significant within and near the burning regions with increases of approx.10-25% in tropospheric column ozone relative to average background concentrations. The model suggests that about half of the increases in ozone from these burning events come from altitudes below 3 km. Globally the model indicates increases of approx.4-5% in ozone, approx.7-9% in NO, (NO+NO2), and approx.30-40% in CO.

  10. Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres

    Science.gov (United States)

    Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.

    2015-05-01

    Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study

  11. A natural experiment on plant acclimation: lifetime stomatal frequency response of an individual tree to annual atmospheric CO2increase

    NARCIS (Netherlands)

    Wagner, F.; Below, R.; Klerk, P. de; Dilcher, D.L.; Joosten, H.; Kürschner, W.M.; Visscher, H.

    1996-01-01

    Carbon dioxide (CO2) has been increasing in atmospheric concentration since the Industrial Revolution. A decreasing number of stomata on leaves of land plants still provides the only morphological evidence that this man-made increase has already affected the biosphere. The current rate of CO2

  12. NOAA JPSS Ozone Mapping and Profiler Suite (OMPS) Version 8 Total Ozone (V8TOz) Environmental Data Record (EDR) from NDE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of total column ozone from the Ozone Mapping and Profiling Suite (OMPS) instrument...

  13. Study of the seasonal ozone variations at European high latitudes

    Science.gov (United States)

    Werner, R.; Stebel, K.; Hansen, H. G.; Hoppe, U.-P.; Gausa, M.; Kivi, R.; von der Gathen, P.; Orsolini, Y.; Kilifarska, N.

    2011-02-01

    The geographic area at high latitudes beyond the polar circle is characterized with long darkness during the winter (polar night) and with a long summertime insolation (polar day). Consequentially, the polar vortex is formed and the surrounding strong polar jet is characterized by a strong potential vorticity gradient representing a horizontal transport barrier. The ozone dynamics of the lower and middle stratosphere is controlled both by chemical destruction processes and transport processes.To study the seasonal ozone variation at high latitudes, ozone vertical distributions are examined, collected from the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) (69.3°N, 16.0°E,) station at Andenes and from the stations at Sodankylä (67.4°N, 26.6°E) and at Ny-Ålesund (78.9°N, 11.9°E). The data sets cover the time period from 1994 until 2004. We find a second ozone maximum near 13-15 km, between the tropopause and the absolute ozone maximum near 17-20 km. The maximum is built up by the combination of air mass transport and chemical ozone destruction, mainly caused by the NOx catalytic cycle, which begins after the polar night and intensifies with the increasing day length. Formation of a troposphere inversion layer is observed. The inversion layer is thicker and reaches higher altitudes in winter rather than in summer. However, the temperature inversion during summer is stronger. The formation of an enhanced ozone number density is observed during the spring-summer period. The ozone is accumulated or becomes poor by synoptic weather patterns just above the tropopause from spring to summer. In seasonal average an ozone enhancement above the tropopause is obtained.The stronger temperature inversion during the summer period inhibits the vertical stratosphere-troposphere exchange. The horizontal advection in the upper troposphere and lower stratosphere is enforced during summer. The combination of these mechanisms generates a layer with a very low

  14. Effect of temperature oscillation on chemical reaction rates in the atmosphere

    Science.gov (United States)

    Eberstein, I. J.

    1974-01-01

    The effect of temperature fluctuations on atmospheric ozone chemistry is examined by considering the Chapman photochemical theory of ozone transport to calculate globally averaged ozone production rates from mean reaction rates, activation energies, and recombination processes.

  15. Antiozonants To Protect Plants from Ozone Damage.

    Science.gov (United States)

    Rich, S; Taylor, G S

    1960-07-15

    Manganous 1,2-naphthoquinone-2-oxime protected tomato foliage in the field from damage apparently caused by excessive atmospheric ozone. The compound proved to be a very effective antiozonant. The similar cobaltous and manganous chelates of 8-quinolinol were also effective antiozonants. The materials were applied to cloth of the type used to make field tents for shade-grown tobacco. Tomato plants covered with cloth treated with cobaltous 8-quinolinolate were protected against otherwise damaging concentrations of ozone. These materials and methods may afford a useful way to reduce weather fleck of tobacco and other plant injuries caused by excessive atmospheric ozone.

  16. Ozone measurements with meteors: a revisit

    Science.gov (United States)

    Ye, Quan-Zhi; Han, Summer Xia

    2017-11-01

    Understanding the role of ozone in the mesosphere/lower thermosphere (MLT) region is essential for understanding the atmospheric processes in the upper atmosphere. Earlier studies have shown that it is possible to use overdense meteor trails to measure ozone concentration in the meteor region. Here, we revisit this topic by comparing a compilation of radar observations to satellite measurements. We observe a modest agreement between the values derived from these two methods, which confirm the usefulness of the meteor trail technique for measuring ozone content at certain heights in the MLT region. Future simultaneous measurements will help quantifying the performance of this technique.

  17. Future Arctic ozone recovery: the importance of chemistry and dynamics

    Directory of Open Access Journals (Sweden)

    E. M. Bednarz

    2016-09-01

    Full Text Available Future trends in Arctic springtime total column ozone, and its chemical and dynamical drivers, are assessed using a seven-member ensemble from the Met Office Unified Model with United Kingdom Chemistry and Aerosols (UM-UKCA simulating the period 1960–2100. The Arctic mean March total column ozone increases throughout the 21st century at a rate of  ∼  11.5 DU decade−1, and is projected to return to the 1980 level in the late 2030s. However, the integrations show that even past 2060 springtime Arctic ozone can episodically drop by  ∼  50–100 DU below the corresponding long-term ensemble mean for that period, reaching values characteristic of the near-present-day average level. Consistent with the global decline in inorganic chlorine (Cly over the century, the estimated mean halogen-induced chemical ozone loss in the Arctic lower atmosphere in spring decreases by around a factor of 2 between the periods 2001–2020 and 2061–2080. However, in the presence of a cold and strong polar vortex, elevated halogen-induced ozone losses well above the corresponding long-term mean continue to occur in the simulations into the second part of the century. The ensemble shows a significant cooling trend in the Arctic winter mid- and upper stratosphere, but there is less confidence in the projected temperature trends in the lower stratosphere (100–50 hPa. This is partly due to an increase in downwelling over the Arctic polar cap in winter, which increases transport of ozone into the polar region as well as drives adiabatic warming that partly offsets the radiatively driven stratospheric cooling. However, individual winters characterised by significantly suppressed downwelling, reduced transport and anomalously low temperatures continue to occur in the future. We conclude that, despite the projected long-term recovery of Arctic ozone, the large interannual dynamical variability is expected to continue in the future, thereby

  18. Ozone monitoring instrument observations of interannual increases in SO2 emissions from Indian coal-fired power plants during 2005-2012.

    Science.gov (United States)

    Lu, Zifeng; Streets, David G; de Foy, Benjamin; Krotkov, Nickolay A

    2013-12-17

    Due to the rapid growth of electricity demand and the absence of regulations, sulfur dioxide (SO2) emissions from coal-fired power plants in India have increased notably in the past decade. In this study, we present the first interannual comparison of SO2 emissions and the satellite SO2 observations from the Ozone Monitoring Instrument (OMI) for Indian coal-fired power plants during the OMI era of 2005-2012. A detailed unit-based inventory is developed for the Indian coal-fired power sector, and results show that its SO2 emissions increased dramatically by 71% during 2005-2012. Using the oversampling technique, yearly high-resolution OMI maps for the whole domain of India are created, and they reveal a continuous increase in SO2 columns over India. Power plant regions with annual SO2 emissions greater than 50 Gg year(-1) produce statistically significant OMI signals, and a high correlation (R = 0.93) is found between SO2 emissions and OMI-observed SO2 burdens. Contrary to the decreasing trend of national mean SO2 concentrations reported by the Indian Government, both the total OMI-observed SO2 and annual average SO2 concentrations in coal-fired power plant regions increased by >60% during 2005-2012, implying the air quality monitoring network needs to be optimized to reflect the true SO2 situation in India.

  19. Ozone Monitoring Instrument Observations of Interannual Increases in SO2 Emissions from Indian Coal-fired Power Plants During 2005-2012

    Science.gov (United States)

    Lu, Zifeng; Streets, David D.; de Foy, Benjamin; Krotkov, Nickolay A.

    2014-01-01

    Due to the rapid growth of electricity demand and the absence of regulations, sulfur dioxide (SO2) emissions from coal-fired power plants in India have increased notably in the past decade. In this study, we present the first interannual comparison of SO2 emissions and the satellite SO2 observations from the Ozone Monitoring Instrument (OMI) for Indian coal-fired power plants during the OMI era of 2005-2012. A detailed unit-based inventory is developed for the Indian coal-fired power sector, and results show that its SO2 emissions increased dramatically by 71 percent during 2005-2012. Using the oversampling technique, yearly high-resolution OMI maps for the whole domain of India are created, and they reveal a continuous increase in SO2 columns over India. Power plant regions with annual SO2 emissions greater than 50 Gg year-1 produce statistically significant OMI signals, and a high correlation (R equals 0.93) is found between SO2 emissions and OMI-observed SO2 burdens. Contrary to the decreasing trend of national mean SO2 concentrations reported by the Indian Government, both the total OMI-observed SO2 and average SO2 concentrations in coal-fired power plant regions increased by greater than 60 percent during 2005-2012, implying the air quality monitoring network needs to be optimized to reflect the true SO2 situation in India.

  20. Balloon-borne Ozonesonde Profile Measurements at South Pole Station, Antarctica During the Ozone Hole of 2015 and 2016.

    Science.gov (United States)

    Johnson, B.; Cullis, P.; Sterling, C. W.; Mcconville, G.; Petropavlovskikh, I. V.

    2016-12-01

    Balloon-borne ozonesondes released by NOAA (National Oceanic Atmospheric Administration) from South Pole Station, Antarctica began in 1986. The 30 year record showed that the 2015 ozone hole was average in ozone loss. Total column ozone dropped from a winter time average of 260 Dobson Units (DU) during June 1- August 15 to a minimum of 112 DU on October 15, 2015 (15th lowest minimum in 30 year record). However, the season was unique in the record number of days the stratospheric vortex air over South Pole remained undisturbed, especially within the main ozone altitude layer from 14-21 km. The ozone loss rates during the month of September in the 14-21 km layer from 1986 to 1990 have averaged 2.3 ± 0.2 DU/day. Since 1991, the ozone loss rate has remained higher at 3.4 ± 0.3 DU/day. 2015 showed a slightly lower loss rate of 3.2 DU/day during September, reaching a minimum of 5 DU on October 12 with complete ozone depletion (zero ozone) observed from 14-18 km. For the next 2 months, ozone slowly increased by about 1 Dobson Unit every 2 days with no sudden increases in ozone or stratospheric temperatures until after December 8, when total column ozone increased by over 100 Dobson Units to 288 DU with much warmer stratospheric air over a broad layer above 15 km, indicating the late arrival of mid-latitude air over South Pole. A consistent decrease in the year-to-year September loss rate within the 14-21 km layer and returning to the 1986-1990 average loss rate of 2.4 ± 0.2 DU/day will be an indicator of long term ozone recovery over South Pole. The 2016 South Pole ozone hole column loss rates and minimum ozone profile measured will be updated in the long term analysis and compared to the total column ozone measurements from the Dobson spectrophotometer record at South Pole.

  1. Largest-ever Ozone Hole over Antarctica

    Science.gov (United States)

    2002-01-01

    A NASA instrument has detected an Antarctic ozone 'hole' (what scientists call an 'ozone depletion area') that is three times larger than the entire land mass of the United States-the largest such area ever observed. The 'hole' expanded to a record size of approximately 11 million square miles (28.3 million square kilometers) on Sept. 3, 2000. The previous record was approximately 10.5 million square miles (27.2 million square km) on Sept. 19, 1998. The ozone hole's size currently has stabilized, but the low levels in its interior continue to fall. The lowest readings in the ozone hole are typically observed in late September or early October each year. 'These observations reinforce concerns about the frailty of Earth's ozone layer. Although production of ozone-destroying gases has been curtailed under international agreements, concentrations of the gases in the stratosphere are only now reaching their peak. Due to their long persistence in the atmosphere, it will be many decades before the ozone hole is no longer an annual occurrence,' said Dr. Michael J. Kurylo, manager of the Upper Atmosphere Research Program, NASA Headquarters, Washington, DC. Ozone molecules, made up of three atoms of oxygen, comprise a thin layer of the atmosphere that absorbs harmful ultraviolet radiation from the Sun. Most atmospheric ozone is found between approximately six miles (9.5 km) and 18 miles (29 km) above the Earth's surface. Scientists continuing to investigate this enormous hole are somewhat surprised by its size. The reasons behind the dimensions involve both early-spring conditions, and an extremely intense Antarctic vortex. The Antarctic vortex is an upper-altitude stratospheric air current that sweeps around the Antarctic continent, confining the Antarctic ozone hole. 'Variations in the size of the ozone hole and of ozone depletion accompanying it from one year to the next are not unexpected,' said Dr. Jack Kaye, Office of Earth Sciences Research Director, NASA Headquarters

  2. Elevated CO{sub 2} and ozone reduce nitrogen acquisition by Pinus halepensis from its mycorrhizal symbiont

    Energy Technology Data Exchange (ETDEWEB)

    Kytoeviita, M.M. [Oulu Univ., Dept. of Biology, Oulu (Finland); Thiec, D. Le [Univ. Henri Poincare-Nancy, Lab. de Biologie Forestiere, Vandoeuvre-les-Nancy (France); Dizengremel, P. [Unite Ecophysiologie Forestiere-Lab. de Pollution Atmospherique, INRA-Centre de Recherches Forestieres, Champenoux (France)

    2001-07-01

    The effects of 700 {mu}mol mol{sup -1} CO{sub 2} and 200 nmol mol{sup -1} ozone on photosynthesis in Pinus halepensis seedlings and on N translocation from its mycorrhizal symbiont, Paxillus involutus, were studied under nutrient-poor conditions. After 79 days of exposure, ozone reduced and elevated CO{sub 2} increased net assimilation rate. However, the effect was dependent on daily accumulated exposure. No statistically significant differences in total plant mass accumulation were observed, although ozone-treated plants tended to be smaller. Changes in atmospheric gas concentrations induced changes in allocation of resources: under elevated ozone, shoots showed high priority over roots and had significantly elevated N concentrations. As a result of different shoot N concentration and net carbon assimilation rates, photosynthetic N use efficiency was significantly increased under elevated CO{sub 2} and decreased under ozone. The differences in photosynthesis were mirrored in the growth of the fungus in symbiosis with the pine seedlings. However, exposure to CO{sub 2} and ozone both reduced the symbiosis-mediated N uptake. The results suggest an increased carbon cost of symbiosis-mediated N uptake under elevated CO{sub 2} while under ozone, plant N acquisition is preferentially shifted towards increased root uptake. (au)

  3. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    Science.gov (United States)

    Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

  4. The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

    Science.gov (United States)

    Kimberly A. Novick; Darren L. Ficklin; Paul C. Stoy; Christopher A. Williams; Gil Bohrer; Andrew C. Oishi; Shirley A. Papuga; Peter D. Blanken; Asko Noormets; Benjamin N. Sulman; Russell L. Scott; Lixin Wang; Richard P. Phillips

    2016-01-01

    Soil moisture supply and atmospheric demand for water independently limit-and profoundly affect-vegetation productivity and water use during periods of hydrologic stress1-4. Disentangling the impact of these two drivers on ecosystem carbon and water cycling is difficult because they are often correlated, and experimental tools for manipulating...

  5. Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise

    Science.gov (United States)

    Trevor F. Keenan; David Y. Hollinger; Gil Boher; Danilo Dragoni; J. William Munger; Hans Peter. Schmid

    2013-01-01

    Terrestrial plants remove CO2 from the atmosphere through photosynthesis, a process that is accompanied by the loss of water vapour from leaves. The ratio of water loss to carbon gain, or water-use efficiency, is a key characteristic of ecosystem function that is central to the global cycles of water, energy and carbon. Here we analyse direct,...

  6. Study of the superficial ozone concentrations in the atmosphere of Comunidad de Madrid using passive samplers Estudio de las concentraciones de ozono superficial en la atmósfera de la Comunidad de Madrid usando muestreadores pasivos

    Directory of Open Access Journals (Sweden)

    E. Díaz Ramiro

    2001-06-01

    Full Text Available The ozone is a secondary atmospheric pollutant which is generated for photochemical reactions of volatil organic compounds (VOC’s and nitrogen oxides (NOx. In Spain the ozone is a big problem as a consequence of the solar radiation to reach high levels. Exposure over a period of time to elevated ozone concentrations can cause damage in the public health and alterations in the vegetation.The aim of this study is to carry out the development and validation of a measurement method to let asses the superficial ozone levels in the Comunidad de Madrid, by identifing the zones more significants, where to measure with UV photometric monitors (automatics methods this pollutant and where the health and the vegetation can be affected. To such effect, passive samplers are used, which have glass fiber filters coated with a solution of sodium nitrite, potassium carbonate, glycerol and water. The nitrite ion in the presence of ozone is oxidized to nitrato ion, which it is extrated with ultrapure water and analyzed for ion chromatography, by seen proportional to the concentration existing in the sampling point.The results of validation from field tests indicate a excellent correlation between the passive and the automatic method.The higher superficial ozone concentrations are placed in rural zones, distanced of emission focus of primary pollutants (nitrogen oxides and volatil organic compounds... principally in direction soutwest and northwest of the Comunidad of Madrid.El ozono es un contaminante atmosférico secundario formado por reacciones fotoquímicas de compuestos orgánicos volátiles (COV y óxidos de nitrógeno (NOx. En España, el ozono es un gran problema como consecuencia de los altos niveles alcanzados por la radiación solar. Exposiciones periódicas a concentraciones elevadas de ozono, pueden causar daños en la salud pública y alteraciones en la vegetación.El objetivo del presente estudio es desarrollar y validar un método de medida que

  7. Increased Growth Factors Play a Role in Wound Healing Promoted by Noninvasive Oxygen-Ozone Therapy in Diabetic Patients with Foot Ulcers

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2014-01-01

    Full Text Available Management of diabetic foot ulcers (DFUs is a great challenge for clinicians. Although the oxygen-ozone treatment improves the diabetic outcome, there are few clinical trials to verify the efficacy and illuminate the underlying mechanisms of oxygen-ozone treatment on DFUs. In the present study, a total of 50 type 2 diabetic patients complicated with DFUs, Wagner stage 2~4, were randomized into control group treated by standard therapy only and ozone group treated by standard therapy plus oxygen-ozone treatment. The therapeutic effects were graded into 4 levels from grade 0 (no change to grade 3 (wound healing. The wound sizes were measured at baseline and day 20, respectively. Tissue biopsies were performed at baseline and day 11. The expressions of vascular endothelial growth factor (VEGF, transforming growth factor-β (TGF-β, and platelet-derived growth factor (PDGF proteins in the pathologic specimens were determined by immunohistochemical examinations. The effective rate of ozone group was significantly higher than that of control group (92% versus 64%, P<0.05. The wound size reduction was significantly more in ozone group than in control group (P<0.001. After treatment, the expressions of VEGF, TGF-β, and PDGF proteins at day 11 were significantly higher in ozone group than in control group. Ozone therapy promotes the wound healing of DFUs via potential induction of VEGF, TGF-β, and PDGF at early stage of the treatment. (Clinical trial registry number is ChiCTR-TRC-14004415.

  8. Tracer-tracer relations as a tool for research on polar ozone loss

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Rolf

    2010-07-01

    The report includes the following chapters: (1) Introduction: ozone in the atmosphere, anthropogenic influence on the ozone layer, polar stratospheric ozone loss; (2) Tracer-tracer relations in the stratosphere: tracer-tracer relations as a tool in atmospheric research; impact of cosmic-ray-induced heterogeneous chemistry on polar ozone; (3) quantifying polar ozone loss from ozone-tracer relations: principles of tracer-tracer correlation techniques; reference ozone-tracer relations in the early polar vortex; impact of mixing on ozone-tracer relations in the polar vortex; impact of mesospheric intrusions on ozone-tracer relations in the stratospheric polar vortex calculation of chemical ozone loss in the arctic in March 2003 based on ILAS-II measurements; (4) epilogue.

  9. Influence of the stratosphere temperature on ozonosphere optical characteristics and instrumental problems of total ozone content remote measurements

    CERN Document Server

    Vaschenko, V M

    2012-01-01

    In this paper we investigate stratosphere temperature impact on remote ozone satellite and ground-based optical observations. High correlation between stratospheric temperature and instrumentally determined total ozone content requires taking into account temperature dependency of ozone absorption and scattering indexes and of other atmosphere characteristics for inverse ozone observations problem solution. The assumption that the majority of observed ozone anomalies and trends are caused by atmosphere temperature change is made.

  10. Increased Growth Factors Play a Role in Wound Healing Promoted by Noninvasive Oxygen-Ozone Therapy in Diabetic Patients with Foot Ulcers

    Science.gov (United States)

    Zhang, Jing; Guan, Meiping; Xie, Cuihua; Luo, Xiangrong; Zhang, Qian; Xue, Yaoming

    2014-01-01

    Management of diabetic foot ulcers (DFUs) is a great challenge for clinicians. Although the oxygen-ozone treatment improves the diabetic outcome, there are few clinical trials to verify the efficacy and illuminate the underlying mechanisms of oxygen-ozone treatment on DFUs. In the present study, a total of 50 type 2 diabetic patients complicated with DFUs, Wagner stage 2~4, were randomized into control group treated by standard therapy only and ozone group treated by standard therapy plus oxygen-ozone treatment. The therapeutic effects were graded into 4 levels from grade 0 (no change) to grade 3 (wound healing). The wound sizes were measured at baseline and day 20, respectively. Tissue biopsies were performed at baseline and day 11. The expressions of vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), and platelet-derived growth factor (PDGF) proteins in the pathologic specimens were determined by immunohistochemical examinations. The effective rate of ozone group was significantly higher than that of control group (92% versus 64%, P Ozone therapy promotes the wound healing of DFUs via potential induction of VEGF, TGF-β, and PDGF at early stage of the treatment. (Clinical trial registry number is ChiCTR-TRC-14004415). PMID:25089169

  11. Co-exposure to ultrafine particulate matter and ozone causes electrocardiogram changes indicative of increased arrhythmia risk in mice

    Science.gov (United States)

    Numerous studies have shown a relationship between acute air pollution exposure and increased risk for cardiovascular morbidity and mortality. Due to the inherent complexity of air pollution, recent studies have focused on co-exposures to better understand potential interactions....

  12. Enrichment of carbon dioxide in the atmosphere increases the capsaicinoids content in Habanero peppers (Capsicum chinense Jacq.).

    Science.gov (United States)

    Garruña-Hernández, René; Monforte-González, Miriam; Canto-Aguilar, Azucena; Vázquez-Flota, Felipe; Orellana, Roger

    2013-04-01

    The effects of the increase of atmospheric CO2 on agricultural productivity have been mainly analyzed through its impact on biomass yield, and little attention has been directed to quality traits, such as nutritional or organoleptic attributes. For this study, plants of hot Habanero pepper (Capsicum chinense Jacq.) were grown in growth chambers under three different CO2 levels: 380 (normal atmospheric value), 760 and 1140 µmol mol(-1), and their effects on pod yield, size, color and pungency, were monitored. The total number of pods per plant increased by 88.5% at the highest CO2 , in comparison to plants grown at normal CO2 conditions. Pod size and yield per plant also increased when plants were grown at the highest CO2 concentration (partial pressure). Furthermore, total capsaicinoids contents in ripe peppers under a high CO2 atmosphere were 27% higher than those from plants under lower concentrations, but it was not the case for immature pods. These data suggest that the increase of atmospheric CO2 could modify specific routes of secondary metabolism as well as others desirable traits, thus affecting the quality of Capsicum pepper products. © 2012 Society of Chemical Industry.

  13. Increased reliability of passive mode-locking a multi-atmosphere TE CO2 laser by injection mode-locking

    NARCIS (Netherlands)

    van Goor, F.A.

    1986-01-01

    By injection of manosecond pulses from an AM mode-locked TEA CO2 laser in a passive mode-locked multi-atmosphere TE CO2 laser the shot-to-shot reproducibility of the generated subnanosecond pulses was increased to almost 100%.

  14. Increasing the speed of computational fluid dynamics procedure for minimization the nitrogen oxide polution from the premixed atmospheric gas burner

    Directory of Open Access Journals (Sweden)

    Fotev Vasko G.

    2017-01-01

    Full Text Available This article presents innovative method for increasing the speed of procedure which includes complex computational fluid dynamic calculations for finding the distance between flame openings of atmospheric gas burner that lead to minimal NO pollution. The method is based on standard features included in commercial computational fluid dynamic software and shortens computer working time roughly seven times in this particular case.

  15. Free atmospheric CO2 enrichment (FACE) increased respiration and humification in the mineral soil of a poplar plantation

    NARCIS (Netherlands)

    Hoosbeek, M.R.; Vos, J.M.; Meinders, M.B.J.; Velthorst, E.J.; Scarascia-Mugnozza, G.

    2007-01-01

    Free atmospheric CO2 enrichment (FACE) studies conducted at the whole-tree and ecosystem scale indicate that there is a marked increase in primary production, mainly allocated into below-ground biomass. The enhanced carbon transfer to the root system may result in enhanced rhizodeposition and

  16. Extensive halogen-mediated ozone destruction over the tropical Atlantic Ocean.

    Science.gov (United States)

    Read, Katie A; Mahajan, Anoop S; Carpenter, Lucy J; Evans, Mathew J; Faria, Bruno V E; Heard, Dwayne E; Hopkins, James R; Lee, James D; Moller, Sarah J; Lewis, Alastair C; Mendes, Luis; McQuaid, James B; Oetjen, Hilke; Saiz-Lopez, Alfonso; Pilling, Michael J; Plane, John M C

    2008-06-26

    Increasing tropospheric ozone levels over the past 150 years have led to a significant climate perturbation; the prediction of future trends in tropospheric ozone will require a full understanding of both its precursor emissions and its destruction processes. A large proportion of tropospheric ozone loss occurs in the tropical marine boundary layer and is thought to be driven primarily by high ozone photolysis rates in the presence of high concentrations of water vapour. A further reduction in the tropospheric ozone burden through bromine and iodine emitted from open-ocean marine sources has been postulated by numerical models, but thus far has not been verified by observations. Here we report eight months of spectroscopic measurements at the Cape Verde Observatory indicative of the ubiquitous daytime presence of bromine monoxide and iodine monoxide in the tropical marine boundary layer. A year-round data set of co-located in situ surface trace gas measurements made in conjunction with low-level aircraft observations shows that the mean daily observed ozone loss is approximately 50 per cent greater than that simulated by a global chemistry model using a classical photochemistry scheme that excludes halogen chemistry. We perform box model calculations that indicate that the observed halogen concentrations induce the extra ozone loss required for the models to match observations. Our results show that halogen chemistry has a significant and extensive influence on photochemical ozone loss in the tropical Atlantic Ocean boundary layer. The omission of halogen sources and their chemistry in atmospheric models may lead to significant errors in calculations of global ozone budgets, tropospheric oxidizing capacity and methane oxidation rates, both historically and in the future.

  17. Antarctic Ozone Hole on September 17, 2001

    Science.gov (United States)

    2002-01-01

    Satellite data show the area of this year's Antarctic ozone hole peaked at about 26 million square kilometers-roughly the size of North America-making the hole similar in size to those of the past three years, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Researchers have observed a leveling-off of the hole size and predict a slow recovery. Over the past several years the annual ozone hole over Antarctica has remained about the same in both its size and in the thickness of the ozone layer. 'This is consistent with human-produced chlorine compounds that destroy ozone reaching their peak concentrations in the atmosphere, leveling off, and now beginning a very slow decline,' said Samuel Oltmans of NOAA's Climate Monitoring and Diagnostics Laboratory, Boulder, Colo. In the near future-barring unusual events such as explosive volcanic eruptions-the severity of the ozone hole will likely remain similar to what has been seen in recent years, with year-to-year differences associated with meteorological variability. Over the longer term (30-50 years) the severity of the ozone hole in Antarctica is expected to decrease as chlorine levels in the atmosphere decline. The image above shows ozone levels on Spetember 17, 2001-the lowest levels observed this year. Dark blue colors correspond to the thinnest ozone, while light blue, green, and yellow pixels indicate progressively thicker ozone. For more information read: 2001 Ozone Hole About the Same Size as Past Three Years. Image courtesy Greg Shirah, GSFC Scientific Visualization Studio, based on data from the TOMS science team

  18. The threee-dimensional morphology of the Antarctic ozone hole

    Science.gov (United States)

    Aikin, Arthur C.; Mcpeters, R. D.

    1988-01-01

    The three-dimensional morphology of the spring antarctic ozone distribution as determined by the Nimbus 7 Solar Backscatter Ultraviolet (SBUV) spectrometer instrument is presented for the period 1 to 11 October in 1986. The data show that a clearly defined minimum in ozone relative to the local ozone field extends throughout the stratosphere from the tropopause to above 50 km, though decreasing in intensity with altitude. Near 18 km ozone in the ozone hole is 50 percent less than the average surrounding ozone. But even at 50 km the ozone is 20 percent less than the surrounding ozone field. The ozone minimum in the upper stratosphere is displaced about 6 degrees toward the equator so that observations at a fixed station may provide the illusion that the ozone minimum is restricted only to low altitudes. While the ozone minimum is spatially coherent throughout the stratosphere, there are differences in the behavior of ozone at different altitudes that suggest the existence of at least three distinct altitude domains. Below 30 km ozone is characterized by classic ozone hole behavior. Between 33 and 43 km ozone is more stable, actually increasing during September and October. Above 43 km ozone has always decreased during September to a minimum in October, but it has suffered a long term decrease of 7 to 12 percent since 1979 similar to that seen at low altitudes.

  19. Attribution of ozone changes to dynamical and chemical processes in CCMs and CTMs

    OpenAIRE

    H. Garny; V. Grewe; M. Dameris; G. E. Bodeker; A. Stenke

    2011-01-01

    Chemistry-climate models (CCMs) are commonly used to simulate the past and future development of Earth's ozone layer. The fully coupled chemistry schemes calculate the chemical production and destruction of ozone interactively and ozone is transported by the simulated atmospheric flow. Due to the complexity of the processes acting on ozone it is not straightforward to disentangle the influence of individual processes on the temporal development of ozone concentrations. A method is introduced ...

  20. Attribution of ozone changes to dynamical and chemical processes in CCMs and CTMs

    OpenAIRE

    H. Garny; V. Grewe; M. Dameris; G. E. Bodeker; A. Stenke

    2011-01-01

    Chemistry-climate models (CCMs) are commonly used to simulate the past and future development of Earth’s ozone layer. The fully coupled chemistry schemes calculate the chemical production and destruction of ozone interactively and ozone is transported by the simulated atmospheric flow. Due to the complexity of the processes acting on ozone it is not straightforward to disentangle the influence of individual processes on the temporal development of ozone concentrations. A method is intro...

  1. Ozone and UV research at Finnish Meteorological Inst.: review of selected results

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorologican Inst., Sodankylae (Finland). Sodankylae Observatory; Ginzburg, M. [Servicio Meteorologico Nacional, Buenos Aires (Argentina); Dijkhuis, J.L. [Finnish Meteorological Inst., Helsinki (Finland). EUMETSAT

    1995-12-31

    Ozone and UV radiation research have become an important part of atmospheric research at Finnish Meteorological Institute after the discovery of chlorine based ozone loss in the Antarctic stratosphere

  2. Stratospheric Water and OzOne Satellite Homogenized (SWOOSH) data set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) data set is a merged record of stratospheric ozone and water vapor measurements taken by a number of...

  3. The 1990 Antarctica ozone hole as observed by TOMS. [Total Ozone Mapping Spectrometer

    Science.gov (United States)

    Newman, Paul; Stolarski, Richard; Schoeberl, Mark; Mcpeters, Richard; Krueger, Arlin

    1991-01-01

    The 1990 Antarctic ozone hole matched the record 1987 ozone hole in depth, duration, and area. During the formation phase of the hole (August), total ozone values were the lowest yet recorded. The decline rate approximately matched the record 1987 decline and reached a minimum of 125 Dobson Units on October 4, 1990. October total ozone averages were marginally higher that 1987. As during 1987, the 1990 total ozone values within the hole slowly and steadily increased during the mid-October through November period. The ozone hole breakup was the latest yet recorded (early December), with low ozone values persisting over the pole through December, setting a record low for December average polar ozone. Temperatures were near average during the early spring, but were below normal for the late spring. Temperatures in the early spring of 1990 were substantially warmer than those observed in the early spring of 1987.

  4. Observation of surface ozone in the marine boundary layer along a cruise through the Arctic Ocean: From offshore to remote

    Science.gov (United States)

    He, Pengzhen; Bian, Lingen; Zheng, Xiangdong; Yu, Juan; Sun, Chen; Ye, Peipei; Xie, Zhouqing

    2016-03-01

    Ozone is an important reactive gas in the troposphere; it has been frequently used to estimate atmospheric oxidation capacity. However, there are few data of surface ozone over the Arctic Ocean, especially the central Arctic Ocean. Here, surface ozone in the marine boundary layer along the cruise path during the 5th Chinese Arctic Research Expedition (June to September, 2012) was investigated. The latitudes and longitudes covered in the cruise were 31.1°N-87.7°N and 9.3°E-90°E-168.4°W. The 1-h-averaged ozone varied from 9.4 ppbv to 124.5 ppbv along the cruise. The highest mixing ratios appeared in the East China Sea and the Sea of Japan while the lowest in the Chukchi Sea. The relatively high ozone levels over the East China Sea, the Sea of Japan, and offshore Iceland were caused by transport of precursors and/or ozone from the nearby continent. Ozone mixing ratio decreasing by ~ 2 ppbv/° with increasing latitude was observed during 31-45°N covering the East China Sea and the Sea of Japan, and during 62-69°N covering offshore Iceland. Over the entire Arctic Ocean, ozone levels were relatively low, varying from 9.4 ppbv to 36.1 ppbv with an average of 23.8 ± 4.6 (mean ± standard deviation) ppbv, which was not statistically different with data observed at Barrow observatory during the same period. Unlike ozone over contaminated areas, a slight increasing trend of ozone in 69-87°N was observed. This phenomenon may be ascribed to the role of both vertical transport and chemical processes due to solar radiation.

  5. A proposed potential role for increasing atmospheric CO2 as a promoter of weight gain and obesity

    DEFF Research Database (Denmark)

    Hersoug, Lars-Georg; Sjödin, Anders Mikael; Astrup, A

    2012-01-01

    Human obesity has evolved into a global epidemic. Interestingly, a similar trend has been observed in many animal species, although diet composition, food availability and physical activity have essentially remained unchanged. This suggests a common factor-potentially an environmental factor...... affecting all species. Coinciding with the increase in obesity, atmospheric CO2 concentration has increased more than 40%. Furthermore, in modern societies, we spend more time indoors, where CO2 often reaches even higher concentrations. Increased CO2 concentration in inhaled air decreases the pH of blood......, which in turn spills over to cerebrospinal fluids. Nerve cells in the hypothalamus that regulate appetite and wakefulness have been shown to be extremely sensitive to pH, doubling their activity if pH decreases by 0.1 units. We hypothesize that an increased acidic load from atmospheric CO2 may...

  6. Atmospheric test of the J(BrONO2/kBrO+NO2 ratio: implications for total stratospheric Bry and bromine-mediated ozone loss

    Directory of Open Access Journals (Sweden)

    S. Kreycy

    2013-07-01

    Full Text Available We report on time-dependent O3, NO2 and BrO profiles measured by limb observations of scattered skylight in the stratosphere over Kiruna (67.9° N, 22.1° E on 7 and 8 September 2009 during the autumn circulation turn-over. The observations are complemented by simultaneous direct solar occultation measurements around sunset and sunrise performed aboard the same stratospheric balloon payload. Supporting radiative transfer and photochemical modelling indicate that the measurements can be used to constrain the ratio J(BrONO2/kBrO+NO2, for which at T = 220 ± 5 K an overall 1.7 (+0.4 −0.2 larger ratio is found than recommended by the most recent Jet Propulsion Laboratory (JPL compilation (Sander et al., 2011. Sensitivity studies reveal the major reasons are likely to be (1 a larger BrONO2 absorption cross-section σBrONO2, primarily for wavelengths larger than 300 nm, and (2 a smaller kBrO+NO2 at 220 K than given by Sander et al. (2011. Other factors, e.g. the actinic flux and quantum yield for the dissociation of BrONO2, can be ruled out. The observations also have consequences for total inorganic stratospheric bromine (Bry estimated from stratospheric BrO measurements at high NOx loadings, since the ratio J(BrONO2/kBrO+NO2 largely determines the stratospheric BrO/Bry ratio during daylight. Using the revised J(BrONO2/kBrO+NO2 ratio, total stratospheric Bry is likely to be 1.4 ppt smaller than previously estimated from BrO profile measurements at high NOx loadings. This would bring estimates of Bry inferred from organic source gas measurements (e.g. CH3Br, the halons, CH2Br2, CHBr3, etc. into closer agreement with estimates based on BrO observations (inorganic method. The consequences for stratospheric ozone due to the revised J(BrONO2/kBrO+NO2 ratio are small (maximum −0.8%, since at high NOx (for which most Bry assessments are made the enhanced ozone loss by overestimating Bry is compensated for by the suppressed ozone loss due to the

  7. The recent increase of atmospheric methane from 10 years of ground-based NDACC FTIR observations since 2005

    Science.gov (United States)

    Bader, Whitney; Bovy, Benoît; Conway, Stephanie; Strong, Kimberly; Smale, Dan; Turner, Alexander J.; Blumenstock, Thomas; Boone, Chris; Collaud Coen, Martine; Coulon, Ancelin; Garcia, Omaira; Griffith, David W. T.; Hase, Frank; Hausmann, Petra; Jones, Nicholas; Krummel, Paul; Murata, Isao; Morino, Isamu; Nakajima, Hideaki; O'Doherty, Simon; Paton-Walsh, Clare; Robinson, John; Sandrin, Rodrigue; Schneider, Matthias; Servais, Christian; Sussmann, Ralf; Mahieu, Emmanuel

    2017-02-01

    Changes of atmospheric methane total columns (CH4) since 2005 have been evaluated using Fourier transform infrared (FTIR) solar obs