WorldWideScience

Sample records for chlorofluorocarbons

  1. Greenhouse effect due to chlorofluorocarbons - Climatic implications

    Science.gov (United States)

    Ramanathan, V.

    1975-01-01

    The infrared bands of chlorofluorocarbons and chlorocarbons enhance the atmospheric greenhouse effect. This enhancement may lead to an appreciable increase in the global surface temperature if the atmospheric concentrations of these compounds reach values of the order of 2 parts per billion.

  2. 40 CFR 721.4360 - Certain hydrogen containing chlorofluorocarbons.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Certain hydrogen containing chlorofluorocarbons. 721.4360 Section 721.4360 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.4360 Certain hydrogen containing chlorofluorocarbons. (a)...

  3. Greenhouse effect of chlorofluorocarbons and other trace gases

    OpenAIRE

    Hansen, James; Lacis, Andrew; Prather, Michael

    1989-01-01

    We compare the radiative (greenhouse) forcing of the climate system due to changes of atmospheric chlorofluorocarbons and other trace gases. We find that CFCs, defined to include chlorofluorocarbons, chlorocarbons, and fluorocarbons, now provide about one-quarter of current annual increases in anthropogenic greenhouse climate forcing. If the growth rates of CFC production in the early 1970s had continued to the present, current annual growth of climate forcing due to CFCs would exceed that du...

  4. Greenhouse effect of chlorofluorocarbons and other trace gases

    Science.gov (United States)

    Hansen, James; Lacis, Andrew; Prather, Michael

    1989-01-01

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

  5. Reduction of chlorofluorocarbon emissions from refrigeration systems

    International Nuclear Information System (INIS)

    Recently enacted State and Federal legislation, (The Clean Air Act and Colorado Senate Bill 77), and the implementation of regulations for each, forbid the intentional release of ozone depleting chlorofluorocarbons(CFCs) from refrigeration and air conditioning systems to the atmosphere. In addition, an international agreement (The Montreal Protocol), calls for CFC manufacturing reductions, which began in 1991, and eventual discontinuation. The declining supply and resultant escalating costs of CFCs are additional driving forces toward conservation and reuse of present refrigerant resources. Rocky Flats Plant (RFP) currently has an estimated 42,000 pounds of CFCs in refrigeration and air conditioning systems. The purpose of this paper is to discuss steps being taken at RFP toward the abatement of CFC releases. The main thrust of our efforts is the use of a refrigerant management system, used to recover and recycle our current CFC stock. Additional methods of further reducing CFC emissions will also be discussed. These include the installation of state-of-the-art oil filtration systems on major chiller units, installation of spring-loaded pressure relief valves and the retrofitting of major chiller units to accept less harmful, alternative refrigerants

  6. Study of Dissolved Chlorofluorocarbons in Lake Washington

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Measurements of three chlorofluorocarbons (CFCs): trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12) and trichlorotrifluoroethane (CFC 113), along with methyl chloroform (CH3CCl3) and carbon tetrachloride (CCl4) were made in water samples from Lake Washington, using Electron Capture Gas Chromatography (EC GC). The samples were collected in mid autumn, a period when the lake's upper layer undergoes rapid cooling. At the time of sampling, a strong vertical temperature gradient was present in the lake, with surface temperatures of ~14℃, and near bottom (50 meters) temperatures of ~8℃. The concentrations of dissolved CFC 12 and CFC 11 increased with depth, as expected from the higher solubilities of these gases at lower temperatures. Atmospheric measurements made at the sampling site at the time of the cruise, showed that CFC 11 and CFC 12 saturations in the near surface samples were 100 % and 106%, respectively. For the deepest sample (52 meters) CFC 11 and CFC 12 saturations were 102 % and 126 %. Because the surface layer of the lake responds to changes in atmospheric CFCs on a time scale of several weeks, the higher than equilibrium concentrations of CFC 12 observed at the time of sampling may reflect earlier episodes of elevated levels of atmospheric CFC 12 in this urban area. High concentrations of dissolved CFCs in runoff or industrial effluent might also lead to elevated CFC levels in the lake. The cold, deep water of Lake Washington is relatively isolated from the effects of surface gas exchange except during winter, and the supersaturations observe in the deep layer may reflect periods of elevated atmospheric CFC 12 levels from the previous winter season. These results were compared to summertime profiles of CFC 11 and CFC 12 made in 1994.

  7. HIRDLS/Aura Level 3 Chlorofluorocarbon-11 (CFC-11) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Chlorofluorocarbon-11 (CFC-11) Zonal Fourier Coefficients" version 7 data product (H3ZFCCFC11) contains the entire mission (~3 years) of...

  8. HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients" version 7 data product (H3ZFCCFC12) contains the entire mission (~3 years) of...

  9. Ross ice shelf cavity circulation, residence time, and melting: Results from a model of oceanic chlorofluorocarbons

    Science.gov (United States)

    Reddy, Tasha E.; Holland, David M.; Arrigo, Kevin R.

    2010-04-01

    Despite their harmful effects in the upper atmosphere, anthropogenic chlorofluorocarbons dissolved in seawater are extremely useful for studying ocean circulation and ventilation, particularly in remote locations. Because they behave as a passive tracer in seawater, and their atmospheric concentrations are well-mixed, well-known, and have changed over time, they are ideal for gaining insight into the oceanographic characteristics of the isolated cavities found under Antarctic ice shelves, where direct observations are difficult to obtain. Here we present results from a modeling study of air-sea chlorofluorocarbon exchange and ocean circulation in the Ross Sea, Antarctica. We compare our model estimates of oceanic CFC-12 concentrations along an ice shelf edge transect to field data collected during three cruises spanning 16 yr. Our model produces chlorofluorocarbon concentrations that are quite similar to those measured in the field, both in magnitude and distribution, showing high values near the surface, decreasing with depth, and increasing over time. After validating modeled circulation and air-sea gas exchange through comparison of modeled temperature, salinity, and chlorofluorocarbons with field data, we estimate that the residence time of water in the Ross Ice Shelf cavity is approximately 2.2 yr and that basal melt rates for the ice shelf average 10 cm yr -1. The model predicts a seasonal signature to basal melting, with highest melt rates in the spring and also the fall.

  10. Steam injection for the thermal plasma destruction of halons and chlorofluorocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, A.B.; Farmer, A.J.D.; Horrigan, E.C. [CSIRO Telecomunications and Industrial Physics, Lindfield NSW (Australia); Mc Allister, T. [CSIRO Telecomunications and Industrial Physics, Clifton Hill Vic (Australia)

    2001-07-01

    The destruction of ozone-depleting substances, in particular chlorofluorocarbons and halons, in the PLASCON plasma process is investigated. In particular, the use of oxygen and steam as oxidising gases is compared. Measurements of the exhaust gas composition are compared with the results Of calculations performed using a comprehensive chemical kinetic scheme. It is found that significant interconversion of ozone-depleting substances occurs, particularly for chloro-fluorocarbon destruction Steam is found to be a superior oxidising gas to oxygen, with greatly reduced levels of ozone-depleting substances and CF{sub 4} in the exhaust gas, particularly if the steam is input at close to or greater than stoichiometric levels. (authors)

  11. Satellite confirmation of the dominance of chlorofluorocarbons in the global stratospheric chlorine budget

    OpenAIRE

    Russell, JM; Luo, M.; Cicerone, RJ; Deaver, LE

    1996-01-01

    OBSERVED increases in concentrations of chlorine in the stratosphere1-7 have been widely implicated in the depletion of lower-stratospheric ozone over the past two decades8-14. The present concentration of stratospheric chlorine is more than five times that expected from known natural 'background' emissions from the oceans and biomass burning15-18, and the balance has been estimated to be dominantly anthropogenic in origin, primarily due to the breakdown products of chlorofluorocarbons (CFCs)...

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

    OpenAIRE

    Newman, P. A; L. D. Oman; A. R. Douglass; Fleming, E. L.; S. M. Frith; M. M. Hurwitz; Kawa, S.R.; Jackman, C. H.; N. A. Krotkov; Nash, E. R.; Nielsen, J. E.; S. Pawson; R. S. Stolarski; G. J. M. Velders

    2009-01-01

    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 research. This science research led to the implementation of international agreements that largely stopped the production of ODSs. In this study we use a fully-c...

  13. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

    NARCIS (Netherlands)

    Allin, S. J.; Laube, J. C.; Witrant, E.; Kaiser, J.; McKenna, E.; Dennis, P.; Mulvaney, R.; Capron, E.; Martinerie, P.; Roeckmann, Thomas; Blunier, T.; Schwander, J.; Fraser, P. J.; Langenfelds, R. L.; Sturges, W. T.

    2015-01-01

    The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O-3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010

  14. Evaluating Potential Bias in Media Coverage of the Public Debate over Acid Rain and Chlorofluorocarbons in the 1980s

    Science.gov (United States)

    Williams, Tiffany Dawn; Moore, Rebecca; Markewitz, Daniel

    2012-01-01

    This study evaluates media coverage of two important environmental issues from the 1980s (acid rain and chlorofluorocarbons), providing historical context for current media coverage analysis. Focusing on popular magazine articles, this study identifies key characteristics of content and presentation. Content-related characteristics are inclusion…

  15. Transport and degradation of chlorofluorocarbons (CFCs) in the pyritic Rabis Creek aquifer, Denmark

    DEFF Research Database (Denmark)

    Hinsby, K.; Hojberg, A.L.; Engesgaard, P.;

    2007-01-01

    Vertical profiles of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113 penetrating aerobic and anaerobic parts of a shallow sandy aquifer show that the CFC gases are degraded in the .... Two-dimensional solute transport simulations with either zero-order or first-order degradation in the anaerobic zone corroborate this interpretation. The transport model was previously calibrated against detailed tritium profiles in the same wells. First-order degradation is found to best match...... the observed CFC profiles yielding an approximate half-life of a few months for CFC-11. Degradation is not as clearly recognized for CFC-12 and CFC-113, but it may occur with rates corresponding to a half-life of a few years or more. Data indicate a geochemical control of the CFC concentration gradient...

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2008-12-01

    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 research. 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-average 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.

  18. Noaa chlorofluorocarbon tracer program air and seawater measurements: 1986-1989. Data file

    International Nuclear Information System (INIS)

    The NOAA Chlorofluorocarbon (CFC) Tracer Program at PMEL has been measuring the growing burden of these anthropogenic gases in the thermocline waters of the Pacific Ocean since 1980. The central goals of the NOAA CFC Tracer Program are to document the transient invasion of the CFC tracers into the Pacific Ocean, by means of repeat occupations of key hydrographic sections at 5-year intervals, and to interpret these changing distributions in terms of coupled ocean-atmosphere models. Studies are underway to use the CFC observations in model-validation studies, and to help develop predictive capabilities on the decade-to-century timescale. The report includes measurements of trichlorofluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12) dissolved in seawater samples collected in the Pacific Ocean by the NOAA CFC Tracer Program on six cruises during the period of 1986-1989. Measurements of depth, pressure, salinity, temperature, and dissolved oxygen are included with the CFC data. Measurements of CFC-11 and CFC-12 in air samples collected along the cruise tracks are also included in the report. Data from the report are also available from the authors in digital format

  19. 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.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J. M.

    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.

  20. Removal of chlorofluorocarbons by increased mass exchange between the stratosphere and troposphere in a changing climate.

    Science.gov (United States)

    Butchart, N; Scaife, A A

    2001-04-12

    Chlorofluorocarbons (CFCs), along with bromine compounds, have been unequivocally identified as being responsible for most of the anthropogenic destruction of stratospheric ozone. With curbs on emissions of these substances, the recovery of the ozone layer will depend on their removal from the atmosphere. As CFCs have no significant tropospheric removal process, but are rapidly photolysed above the lower stratosphere, the timescale for their removal is set mainly by the rate at which air is transported from the troposphere into the stratosphere. Using a global climate model we predict that, in response to the projected changes in greenhouse-gas concentrations during the first half of the twenty-first century, this rate of mass exchange will increase by 3% per decade. This increase is due to more vigorous extra-tropical planetary waves emanating from the troposphere. We estimate that this increase in mass exchange will accelerate the removal of CFCs to an extent that recovery to levels currently predicted for 2050 and 2080 will occur 5 and 10 years earlier, respectively. PMID:11298444

  1. Destruction of concentrated chlorofluorocarbons in India demonstrates an effective option to simultaneously curb climate change and ozone depletion

    International Nuclear Information System (INIS)

    Highlights: • Chlorofluorocarbons and halons are potent ozone depleting substances and greenhouse gases. • No provisions in the Montreal or in Kyoto Protocol to destroy stockpiles of concentrated CFCs. • The UNEP recommends 11 technologies for destruction of concentrated CFCs. • No studies have up to now investigated the potential of using cement kilns in developing countries. • The test demonstrated that the local Indian cement kiln was able to destroy high feeding rates of several concentrated CFC-gases effectively. - Abstract: The Montreal Protocol aims to protect the stratospheric ozone layer by phasing out production of substances that contribute to ozone depletion, currently covering over 200 individual substances. As most of these compounds are synthetic greenhouse gases, there is an opportunity to curb both ozone depletion and climate change simultaneously by requiring Parties of both the Montreal and the Kyoto Protocol to destroy their existing stocks of concentrated chlorofluorocarbons (CFCs). Many emerging countries still possess stocks which need to be destroyed in an environmentally sound manner but costs may be prohibitive. The UNEP Technology and Economic Assessment Panel identified in 2002 eleven destruction technologies which meet the criteria for environmentally sound destruction of chlorofluorocarbons. Cement kilns were among these, but no study has been reported in scientific literature assessing its destruction performance under real developing country conditions up to now. In contrast to incinerators and other treatment techniques, high temperature cement kilns are already in place in virtually every country and can, if found technical feasible, be retrofitted and adapted cost-efficiently to destroy chemicals like CFCs. India has the second largest cement industry in the world and several hazardous waste categories have been tested successfully in recent years. The objective of this study was to carry out the first full scale

  2. Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities)...

  3. Age dating ground water by use of chlorofluorocarbons (CCl3F and CCl2F2), and distribution of chlorofluorocarbons in the unsaturated zone, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho

    International Nuclear Information System (INIS)

    Detectable concentrations of chlorofluorocarbons (CFC's) were observed in ground water and unsaturated-zone air at the Idaho National Engineering Laboratory (INEL) and vicinity. The recharge ages of waters were determined to be from 4 to more than 50 years on the basis of CFC concentrations and other environmental data; most ground waters have ages of 14 to 30 years. These results indicate that young ground water was added at various locations to the older regional ground water (greater than 50 years) within and outside the INEL boundaries. The wells drilled into the Snake River Plain aquifer at INEL sampled mainly this local recharge. The Big Lost River, Birch Creek, the Little Lost River, and the Mud Lake-Terreton area appear to be major sources of recharge of the Snake River Plain aquifer at INEL. An average recharge temperature of 9.7±1.3 degrees C (degrees Celsius) was calculated from dissolved nitrogen and argon concentrations in the ground waters, a temperature that is similar to the mean annual soil temperature of 9 degrees C measured at INEL. This similarity indicates that the aquifer was recharged at INEL and not at higher elevations that would have cooler soil temperatures than INEL. Soil-gas concentrations at Test Area North (TAN) are explained by diffusion theory

  4. On Cosmic-Ray-Driven Electron Reaction Mechanism for Ozone Hole and Chlorofluorocarbon Mechanism for Global Climate Change

    CERN Document Server

    Lu, Qing-Bin

    2012-01-01

    Numerous laboratory measurements have provided a sound physical basis for the cosmic-ray driven electron-induced reaction (CRE) mechanism of halogen-containing molecules for the ozone hole. And observed spatial and time correlations between polar ozone loss or stratospheric cooling and cosmic rays have shown strong evidence of the CRE mechanism [Q.-B. Lu, Phys. Rep. 487, 141-167(2010)]. Chlorofluorocarbons (CFCs) were also long-known greenhouse gases but were thought to play only a minor role in climate change. However, recent observations have shown evidence of the saturation in greenhouse effect of non-CFC gases. A new evaluation has shown that halocarbons alone (mainly CFCs) could account for the rise of 0.5~0.6 deg C in global surface temperature since 1950, leading to the striking conclusion that not CO2 but CFCs were the major culprit for global warming in the late half of the 20th century [Q.-B. Lu, J. Cosmology 8, 1846-1862(2010)]. Surprizingly, a recent paper [J.-W. Grooss and R. Muller, Atmos. Envir...

  5. WO3/ZrO2 Strong Acid as a Catalyst for the Decomposition of Chlorofluorocarbon (CFC-12)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Introduction Chlorofluorocarbons (CFCs) diffusing to the stratosphere is a major reason for ozone depletion[1]. Also CFCs has been claimed to be notorious for its greenhouse effect[2]. So, recently it has become very important to eliminate CFCs as far as protecting the ozone layer surrounding the earth is concerned. Among various kinds of approaches to do destruction to CFCs, the catalytic decomposition seems to be the most practical and energetically favorable one, especially for treating small amounts of CFCs[3,4]. Recently, Fu et al.[3] reported that TiO2 modified with H2SO4 was much more active than TiO2 for the decomposition of CFC-12 in the presence of water vapor, and they attributed this tremendous enhancement in activity to the superacidic property of the sulfated catalyst. Their research results substantially stimulate us to investigate the catalytic decomposition of CFC-12 in the presence of water vapor over WO3/ZrO2 strong acid, which is more thermally stable than the sulfated oxides superacids[5].

  6. Summary record: Workshop on alternatives to chlorofluorocarbons as solvents. Held in Irvine, California on June 17-18, 1991

    International Nuclear Information System (INIS)

    The impetus for minimization or elimination of chlorofluorocarbons (CFCs) comes from the growing body of knowledge concerning depletion of the stratospheric ozone layer and formation of polar ozone 'holes'. The workshop concentrated on solvent usage, which constitutes some 12% of CFCs contribution to ozone depletion and is estimated by the U.S. Environmental Protection Agency (EPA) at a sales dollar volume of $145 million per year for the United States alone. There is widespread solvent use in the electronics, automotive, defense, and spacecraft industries, as well as by a myriad of smaller fabricators and for consumer products. Seventeen major corporations in collaboration with the EPA, have formed the Industry Cooperative for Ozone Layer Protection (ICOLP). Two meetings were held prior to the workshop. The first included presentations by representatives from the ICOLP member companies on the pertinent activities of their respective organizations. The objective of this meeting was to brief the steering committee on the needs, limitations, problems, and successes in the development of alternatives to CFCs. Much of the background material presented in the workshop report was compiled during this first meeting. The objectives of the second meeting of the steering committee were to plan the agenda for the workshop and to identify the industry representatives to be invited

  7. Linking chloride mass balance infiltration rates with chlorofluorocarbon and SF6 groundwater dating in semi-arid settings: potential and limitations.

    Science.gov (United States)

    Stadler, Susanne; Osenbruck, Karsten; Duijnisveld, Wilhelmus H M; Schwiede, Martin; Bottcher, Jurgen

    2010-09-01

    In the framework of the investigation of enrichment processes of nitrate in groundwater of the Kalahari of Botswana near Serowe, recharge processes were investigated. The thick unsaturated zone extending to up to 100 m of mostly unconsolidated sediments and very low recharge rates pose a serious challenge to study solute transport related to infiltration and recharge processes, as this extends past the conventional depths of soil scientific investigations and is difficult to describe using evidence from the groundwater due to the limitations imposed by available tracers. To determine the link between nitrate in the vadose zone and in the uppermost groundwater, sediment from the vadose zone was sampled up to a depth of 15-20 m (in one case also to 65 m) on several sites with natural vegetation in the research area. Among other parameters, sediment and water were analysed to determine chloride and nitrate concentration depth profiles. Using the chloride mass balance method, an estimation of groundwater infiltration rates produced values of 0.2-4 mm a(-1). The uncertainty of these values is, however, high. Because of the extreme thickness of the vadose zone, the travel time in the unsaturated zone might reach extreme values of up to 500 years and more. For investigations using groundwater, we applied the chlorofluorocarbons CFC-113, CFC-12, sulphur hexafluoride (SF(6)) and tritium to identify potential recharge, and found indications for some advective transport of the CFCs and SF(6), which we accounted for as constituting potential active localised recharge. In our contribution, we show the potential and limitations of the applied methods to determine groundwater recharge and coupled solute transport in semi-arid settings, and compare travel time ranges derived from soil science and groundwater investigations.

  8. National action plan for recovery, recycling and reclamation of chlorofluorocarbons (CFC's); Part 2. Piano operativo nazionale per il recupero, il riciclaggio, il trattamento dei clorofluorocarburi (CFC); Parte 2

    Energy Technology Data Exchange (ETDEWEB)

    Relevant to the development of a plan for the recovery, recycling and reclamation of chlorofluorocarbons (CFC's), this paper tables a list of operating task activities and recommendations. They include: the creation of incentives for CFC recovery and recycling; the setting up of a recovered materials monitoring system; the drafting up of emission limits; information dissemination for greater public awareness; collaboration with owners and builders of plants using CFC's; development of suitable waste management and disposal procedures for CFC residuals.

  9. National action plan for recovery, recycling and reclamation of chlorofluorocarbons (CFC's); Part 1. Piano operativo nazionale per il recupero, il riciclaggio, il trattamento dei clorofluorocarburi (CFC); Parte prima

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    This report develops a plan for the recovery recycling, and reclamation of chlorofluorocarbons (CFC's) for reuse in Canada to ensure that the large consumer and marketplace inventory of these compounds does not enter the atmosphere. Reuse is further necessary for future operation of equipment when the production and importation of CFC's becomes severely restricted or is eliminated. The report also deals with the need to recover hydrochlorofluorocarbons (HCFC's) for reuse. A harmonized national action plan containing a set of agreed-upon objectives and tasks is developed to provide a basis for federal and provincial programs, regulatory action, and data development.

  10. Metabolism of the chlorofluorocarbon substitute 1,1-dichloro-2,2,2-trifluoroethane by rat and human liver microsomes: the role of cytochrome P450 2E1.

    Science.gov (United States)

    Urban, G; Speerschneider, P; Dekant, W

    1994-01-01

    1,1-Dichloro-2,2,2-trifluoroethane (HCFC-123) has been developed as a substitute for ozone-depleting chlorofluorocarbons. The atmospheric lifetime of HCFC-123 is expected to be much shorter than those of chlorofluorocarbons; however, due to its lower stability and the presence of carbon-hydrogen bonds, metabolism of HCFC-123 in mammals and metabolism-dependent toxicity is likely. We compared the metabolism of HCFC-123 and its analog halothane in rat and human liver microsomes. 19F-NMR studies showed that trifluoroacetic acid is a major metabolite of HCFC-123. Besides trifluoroacetic acid, chlorodifluoroacetic acid and inorganic fluoride were identified as products of the enzymatic oxidation of HCFC-123 in rat and human liver microsomes by 19F-NMR and mass spectrometry. The metabolites were not detected in incubations with halothane. HCFC-123 and halothane were transformed by liver microsomes from untreated rats at low rates. Microsomes from ethanol-and pyridine-treated rats metabolized both HCFC-123 and halothane at much higher rates. These microsomes also exhibited high rates of p-nitrophenol oxidation. p-Nitrophenol is a model substrate mainly oxidized by P450 2E1 to p-nitrocatechol. Samples of human liver microsomes showed considerable differences in the extent of HCFC-123, p-nitrophenol oxidation, and chlorzoxazone hydroxylation. In human liver microsomes, rabbit anti-rat P450 2E1 IgG recognized a single protein band corresponding in apparent molecular weight to human P450 2E1. Immunoblot analysis revealed considerable heterogenity in the P450 2E1 protein content of the human liver samples. Trifluoroacetic acid formation from HCFC-123 and halothane and p-nitrocatechol formation from p-nitrophenol were significantly reduced by the P450 2E1 inhibitor diethyldithiocarbamate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8199305

  11. The CFC-ozone problem and possibilities for reducing emissions of chlorofluorocarbons in refrigeration engineering, air conditioning, and heat pump engineering. 2. ed. Das FCKW-Ozon-Problem und Moeglichkeiten der Emissionsreduzierung von Fluorchlorkohlenwasserstoffen fuer die Kaelte-, Klima- und Waermepumpentechnik

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-01

    Political activities under way world-wide aim to cut down on the production of chlorofluorocarbons as a prophylactic means to reduce emissions from their application before hand, for the benefit of the ozone layer - in the sectors of aerosol technology (spray-cans), polyurethane foam and expanded foam (for instance for thermal insulation purposes and for packaging), refigerants in refrigeration engineering, or solvents in dry cleaning. The factors to be considered in refrigeration engineering, and viable possibilities are explained in this status report. The advantageous properties of CFC 11 and 12, often referred to by the household term of 'safety refrigerants', as compared to refrigerants formerly used, are described; so is their use in the comprehensive spectrum of refrigeration technology, whose importance in modern life is also briefly dealt with. - The second part of the status report is concerned with the conributions of refrigeration engineering towards cutting down CFC emissions. First of all, the question of substitutes is dealt with. A further point of emphasis consists in the reduction of CFC emissions from technical plants - considering the 'code of good pratices' published in 1984 - and the rules to adhere by when accepting used refrigerants, as well as the possibilities for their disposal. - The report is rounded off by some production figures on CFCs and explanations regarding the safety precautions to be taken at refrigerators, heat pumps, and cooling appliances, which are to be observed when using different refrigerants including CFCs. (orig./UA).

  12. Energy Efficient Alternatives to Chlorofluorocarbons (CFCs)

    Energy Technology Data Exchange (ETDEWEB)

    None

    1993-06-01

    An assessment of the state of the art in refrigeration and insulation technologies is carried out to evaluate the potential for efficient substitutes for CFCs and HCFCs to facilitate the transition to a CFC-free environment. Opportunities for improved efficiency in domestic refrigeration, building chillers, commercial refrigeration and industrial refrigeration are evaluated. Needs for alternate refrigerants, improved components, and/or alternate cycles are identified. A summary of on-going research is presented in each area, and the potential roles of industry and government are considered. The most promising approaches for refrigeration technology fall into these categories: (1) improved vapor compressor cycles with alternate fluids, (2) Stirling cycle development and (3) advances in absorption technology. A summary of on-going research into advanced insulation, focused on vacuum-based insulation technology refrigeration is developed. Insulation applications considered include appliances, transport refrigeration, and buildings. Specific recommendations for a long-term R&D agenda are presented. The potential benefits, research, general approach, and probability of success are addressed.

  13. International research into chlorofluorocarbon (CFC) alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Shankle, D.L.; Thurman, A.G.

    1992-05-01

    Selected researchers from 21 countries were queried through questionnaires about their current and planned research activities. The results of the survey show that the majority of research being conducted by the respondents is devoted to investigating the hydrogenated fluorocarbon HFC-134a as a replacement for CFC-12 in refrigeration applications. The main issue with this alternative is identifying compatible lubricants that do not reduce its effectiveness.

  14. Chapter 2. Chlorofluorocarbons in the atmosphere

    International Nuclear Information System (INIS)

    CFCs were predominantly consumed and released by industrialized nations between the latitudes of 30 deg. N and 70 deg. N (Hartley et al., 1996); therefore, the troposphere mixing ratios in the northern hemisphere historically have been higher than those of the southern hemisphere. However, with the phasing out of CFC production by the developed countries (Montreal Protocol on Substances that Deplete the Ozone Layer), the interhemispheric differences in the mixing ratios have appreciably decreased. Near urban areas, some CFC mixing ratios are often raised relative to background air composition. If these differences are neglected, then the calculated age of the water from these urban or densely populated sites will appear contaminated or younger than the actual recharge age of the groundwater

  15. Global warming from chlorofluorocarbons and their alternatives: Time scales of chemistry and climate

    OpenAIRE

    KO, MALCOLM K.W.; SZE, NIEN DAK; Molnar, Gyula; PRATHER, MICHAEL J.

    1993-01-01

    The halocarbons (chloroflurocarbons, CFCs, and their replacement chemicals: the hydrochloroflurocarbons, HCFCs, and the hydrofluorocarbons, HFCs) are greenhouse gases. The atmospheric accumulation of these gases is expected to add to the global warming predicted for expected increases of CO2, CH4, N2O, tropospheric ozone and H2O. Over the next decades, production of CFCs is scheduled to be phased out, while emissions of their alternatives are expected to increase. A simple model is used to il...

  16. A research needs assessment: Energy efficient alternatives to chlorofluorocarbons (CFCs). Final reprot

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    An assessment of the state of the art in refrigeration and insulation technologies is carried out to evaluate the potential for efficient substitutes for CFCs and HCFCs to facilitate the transition to a CFC-free environment. Opportunities for improved efficiency in domestic refrigeration, building chillers, commercial refrigeration and industrial refrigeration are evaluated. Needs for alternate refrigerants, improved components, and/or alternate cycles are identified. A summary of on-going research is presented in each area, and the potential roles of industry and government are considered. The most promising approaches for refrigeration technology fall into these categories: (1) improved vapor compressor cycles with alternate fluids, (2) Stirling cycle development and (3) advances in absorption technology. A summary of on-going research into advanced insulation, focused on vacuum -- based insulation technology refrigeration is developed. Insulation applications considered include appliances, transport refrigeration, and buildings. Specific recommendations for a long-term R&D agenda are present. The potential benefits, research, general approach, and probability of success are addressed.

  17. An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2002-01-01

    Full Text Available Using historical observations and model simulations, we investigate ozone trends prior to the mid-1970s onset of halogen-induced ozone depletion. Though measurements are quite limited, an analysis based on multiple, independent data sets (direct and indirect provides better constraints than any individual set of observations. We find that three data sets support an apparent long-term stratospheric ozone trend of -7.2 ± 2.3 DU during 1957-1975, which modeling attributes primarily to water vapor increases. The results suggest that 20th century stratospheric ozone depletion may have been roughly 50% more than is generally supposed. Similarly, three data sets support tropospheric ozone increases over polluted Northern Hemisphere continental regions of 8.2 ± 2.1 DU during this period, which are mutually consistent with the stratospheric trends. As with paleoclimate data, which is also based on indirect proxies and/or limited spatial coverage, these results must be interpreted with caution. However, they provide the most thorough estimates presently available of ozone changes prior to the coincident onset of satellite data and halogen dominated ozone changes. If these apparent trends were real, the radiative forcing by stratospheric ozone since the 1950s would then have been -0.15 ± 0.05 W/m2, and -0.2 W/m2 since the preindustrial. For tropospheric ozone, it would have been 0.38 ± 0.10 W/m2 since the late 1950s. Combined with even a very conservative estimate of tropospheric ozone forcing prior to that time, this would be larger than current estimates since 1850 which are derived from models that are even less well constrained. These calculations demonstrate the importance of gaining a better understanding of historical ozone changes.

  18. The elimination of chlorinated, chlorofluorocarbon, and other RCRA hazardous solvents from the Y-12 Plant's enriched uranium operations

    International Nuclear Information System (INIS)

    A major driving force in waste minimization within the plant is the reduction of mixed radioactive wastes associated with operations on highly enriched uranium. High enriched uranium has a high concentration of the uranium-235 isotope (up to 97.5% enrichment) and is radioactive, giving off alpha and low level gamma radiation. The material is fissionable with as little as two pounds dissolved in water being capable of producing a spontaneous chain reaction. For these reasons the material is processed in small batches or small geometries. Additionally, the material is completely recycled because of its strategic and monetary value. Since the early eighties, the plant has had an active waste minimization program which has concentrated on substitution of less hazardous solvents wherever possible. The following paper summarizes efforts in two areas - development of a water-based machining coolant to replace perchloroethylene and substitution of an aliphatic solvent to replace solvents producing hazardous wastes as defined by the Resource, Conservation, and Recovery Act (RCRA)

  19. Chlorofluorocarbons and ~3H/~3He in groundwater——Applications in tracing and dating young groundwater

    Institute of Scientific and Technical Information of China (English)

    秦大军; 王浩

    2001-01-01

    Based on the CFC concentration, the fraction of young groundwater in a mixture with old groundwater can be defined if the age of the young component is known. The authors argued that the ratio of [3HeJ/[3Ht] in a young water is independent of its mixing with old waters. Hence, the 3H-3He can be used to determine age of the young groundwater, though mixing with old ground-water may occur. CFC concentrations are susceptible to change by mixing of young and old water. The combination of CFCs and tritium/helium can provide confidential apparent age of the young groundwater and fraction of the young water in the mixture with old groundwater.

  20. Reaction dynamics following electron capture of chlorofluorocarbon adsorbed on water cluster : a direct density functional theory molecular dynamics study

    OpenAIRE

    Tachikawa, Hiroto; ABE, Shigeaki

    2007-01-01

    The electron capture dynamics of halocarbon and its water complex have been investigated by means of the full dimensional direct density functional theory molecular dynamics method in order to shed light on the mechanism of electron capture of a halocarbon adsorbed on the ice surface. The CF2Cl2 molecule and a cyclic water trimer (H2O)3 were used as halocarbon and water cluster, respectively. The dynamics calculation of CF2Cl2 showed that both C–Cl bonds are largely elongated after the electr...

  1. Chlorofluorocarbons, Sulfur Hexafluoride, and Dissolved Permanent Gases in Ground Water from Selected Sites In and Near the Idaho National Engineering and Environmental Laboratory, Idaho, 1994 - 1997

    Energy Technology Data Exchange (ETDEWEB)

    Busenberg, E.; Plummer, L.N.; Bartholomay, R.C.; Wayland, J.E.

    1998-08-01

    From July 1994 through May 1997, the U.S. Geological Survey, in cooperations with the Department of Energy, sampled 86 wells completed in the Snake River Plain aquifer at and near the Idaho National Engineering and Environmental Laboratory (INEEL). The wells were sampled for a variety of constituents including one- and two-carbon halocarbons. Concentrations of dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), and trichlorotrifluororoethane (CFC-113) were determined. The data will be used to evaluate the ages of ground waters at INEEL. The ages of the ground water will be used to determine recharge rates, residence time, and travel time of water in the Snake River Plain aquifer in and near INEEL. The chromatograms of 139 ground waters are presented showing a large number of halomethanes, haloethanes, and haloethenes present in the ground waters underlying the INEEL. The chromatograms can be used to qualitatively evaluate a large number of contaminants at parts per trillion to parts per billion concentrations. The data can be used to study temporal and spatial distribution of contaminants in the Snake River Plain aquifer. Representative compressed chromatograms for all ground waters sampled in this study are available on two 3.5-inch high density computer disks. The data and the program required to decompress the data can be obtained from the U.S. Geological Survey office at Idaho Falls, Idaho. Sulfur hexafluoride (SF6) concentrations were measured in selected wells to determine the feasibility of using this environmental tracer as an age dating tool of ground water. Concentrations of dissolved nitrogen, argon, carbon dioxide, oxygen, and methane were measured in 79 ground waters. Concentrations of dissolved permanent gases are tabulated and will be used to evaluate the temperature of recharge of ground water in and near the INEEL.

  2. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from April 30th, 2004 to May 5th, 2004 (NODC Accession 0063574)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represent one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of 54...

  3. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from April 9th, 2007 to April 13th, 2007 (NODC Accession 0063580)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  4. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from October 13th, 2005 to October 17th, 2005 (NODC Accession 0063577)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represent one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of 16...

  5. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from October 19th, 2006 to October 24th, 2006 (NODC Accession 0063579)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  6. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from April 5th, 2006 to April 14th, 2006 (NODC Accession 0063578)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represent one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of 17...

  7. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from May 10th, 2008 to May 19th, 2008 (NODC Accession 0063581)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  8. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V ENDEAVOR in the Northwest Atlantic from October 1st, 2007 to October 7th, 2007 (NODC Accession 0063743)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  9. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from April 26th, 2005 to May 3rd, 2005 (NODC Accession 0063576)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  10. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V CAPE HATTERAS in the Northwest Atlantic from September 6th, 2004 to September 11th, 2004 (NODC Accession 0063575)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of...

  11. Line W Hydrography including pressure, temperature, salinity, dissolved oxygen, sulfur hexafluoride, and dissolved chlorofluorocarbons from bottle and CTD casts from the R/V OCEANUS in the Northwest Atlantic from August 31st, 2009 to September 7th, 2009 (NODC Accession 0068682)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represent one of a series of hydrographic sections conducted along Line W from the continental shelf south of New England toward Bermuda. A total of 26...

  12. Bad Science and Its Social Implications.

    Science.gov (United States)

    Zeidler, Dana L.; Sadler, Troy D.; Berson, Michael J.; Fogelman, Aimee L.

    2002-01-01

    Investigates three types of bad science: (1) cultural prejudice based on scientific errors (polygenism, phrenology, reification through intelligence testing); (2) unethical science (Tuskegee syphilis experiments, tobacco companies and research); and (3) unwitting errors (pesticides, chlorofluorocarbons). (Contains 50 references.) (SK)

  13. MANUAL FOR NON-CFC AEROSOL PACKAGING: CONVERSION FROM CFC TO HYDROCARBON PROPELLANTS

    Science.gov (United States)

    The report provides technical assistance to aerosol product marketers and fillers in other nations now faced with eliminating chlorofluorocarbons (CFCs) under the terms of the Montreal Protocol. t addresses the issues of hydrocarbon propellant supply, product reformulation, equip...

  14. IDENTIFICATION OF CFC AND HCFC SUBSTITUTES FOR BLOWING POLYURETHANE FOAM INSULATION PRODUCTS

    Science.gov (United States)

    The report gives results of a cooperative effort to identiry chlorofluorocarbons and hydrochlorofluorocarbon substitutes for blowing polyurethane foam insulation products. The substantial ongoing effort is identifying third-generation blowing agets for polyurethane foams to repla...

  15. GREENHOUSE GASES AND AGRICULTURE

    Science.gov (United States)

    Agriculture ranks third in its contribution to Earth's anthropogenically nhanced greenhouse effect. Energy use and production and chlorofluorocarbons are anked first and second, respectively.) pecifically, greenhouse gas sources and inks are increased, and sinks are decreased, by...

  16. HFK's en het (H)CFK-reductiebeleid in relatie tot het beleid inzake Nederlandse emissies van broeikasgassen. Scenario's voor mondiaal en Nederlands gebruik van gehydrogeneerde fluorkoolwaterstoffen en hun relatie met het broeikas-effect

    NARCIS (Netherlands)

    Olivier JGJ; Kroeze C; Matthijsen AJCM; Woerd HJ van der; LAE; LLO

    1994-01-01

    Hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are important substitutes for chlorofluorocarbons (CFCs) and halons. HCFCs have a lower Ozone Depleting Potential (ODP) than CFCs and halons, and are therefore considered temporary substitutes, while HFCs have zero ODP. In addition to O

  17. ON ESTIMATING AGRICULTURE'S NET CONTRIBUTION TO ATMOSPHERIC CARBON

    Science.gov (United States)

    Fossil fuel combustion, chlorofluorocarbon releases, and agricultural activities (including deforestation) are the primary anthropogenic sources of greenhouse gases. Of the three sources, agriculture is the only one that also has a sink capacity. Thus, an accounting of the net ca...

  18. Fluticasone Propionate, 100 µg bid, Using a Non-CFC Propellant, HFA 134a, in Asthmatic Children

    Directory of Open Access Journals (Sweden)

    Brian Lyttle

    2003-01-01

    Full Text Available BACKGROUND: Secondary to phasing out chlorofluorocarbons (CFCs, the fluticasone propionate (FP pressurized metered-dose inhaler has been formulated in a nonozone-depleting propellant, hydrofluoralkane (HFA 134a.

  19. Projects for a Healthy Planet: Simple Environmental Experiments for Kids.

    Science.gov (United States)

    Levine, Shar; Grafton, Allison

    1992-01-01

    Presents two experiments about ozone related topics. The first experiment examines the effect of sunlight on newsprint and relates this to human skin. The second demonstrates how chemicals, and specifically chlorofluorocarbons travel through the air. (MCO)

  20. CONTROL TECHNOLOGY OVERVIEW REPORT: CFC-11 EMISSIONS FROM FLEXIBLE POLYURETHANE FOAM MANUFACTURING

    Science.gov (United States)

    The report gives results of an engineering evaluation of technical options to reduce chlorofluorocarbon (CFC) emissions from flexible slabstock and molded polyurethane foam manufacturing plants. Among the technical options studied were recovery and recycle of CFC-11, alternative ...

  1. EPA (ENVIRONMENTAL PROTECTION AGENCY) WORKSHOP ON GLOBAL ATMOSPHERIC CHANGE AND EPA PLANNING

    Science.gov (United States)

    Expanding industrial and agricultural growth are leading to greater emissions of many compounds that are changing the earth's atmosphere and climate. The changes are warming of the climate caused by greenhouse gases, stratospheric ozone modifications caused by chlorofluorocarbons...

  2. Atmospheric lifetimes of selected fluorinated ether compounds

    DEFF Research Database (Denmark)

    Heathfield, A.E.; Anastasi, C.; Pagsberg, Palle Bjørn;

    1998-01-01

    Atmospheric lifetimes have been estimated for a selection of ethers, the latter representing a class of compounds being considered as replacements for chlorofluorocarbons. The estimates are based on laboratory measurements of rate constants for the reaction of the OH radical with the ethers......, and a comparison with the behaviour of methyl chloroform in the atmosphere. The lifetimes for the ethers ranged from a few hours to half a year, significantly lower than those of chlorofluorocarbons and other replacements being considered. (C) 1998 Elsevier Science Ltd. All rights reserved....

  3. Decline of deep and bottom water ventilation and slowing down of anthropogenic carbon storage in the Weddell Sea, 1984-2011

    NARCIS (Netherlands)

    Huhn, Oliver; Rhein, Monika; Hoppema, Mario; van Heuven, Steven

    2013-01-01

    We use a 27 year long time series of repeated transient tracer observations to investigate the evolution of the ventilation time scales and the related content of anthropogenic carbon (C-ant) in deep and bottom water in the Weddell Sea. This time series consists of chlorofluorocarbon (CFC) observati

  4. 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; 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 intermed

  5. Ozone: apocalypse or misinformation

    International Nuclear Information System (INIS)

    This paper debates about the origin of the destruction of ozone layer in the stratosphere. Chlorofluorocarbons don't seem to be the single responsible agent but chloric acid from volcanic eruptions, chlorinated compounds of oceans or biomass combustion are another major sources. 13 refs., 3 figs

  6. Ozone: apocalypse or misinformation. Ozone: apocalypse ou desinformation

    Energy Technology Data Exchange (ETDEWEB)

    Domblides, J.P.

    1993-04-01

    This paper debates about the origin of the destruction of ozone layer in the stratosphere. Chlorofluorocarbons don't seem to be the single responsible agent but chloric acid from volcanic eruptions, chlorinated compounds of oceans or biomass combustion are another major sources. 13 refs., 3 figs.

  7. 16 CFR 1401.1 - Scope.

    Science.gov (United States)

    2010-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SELF PRESSURIZED... Product Safety Act (15 U.S.C. 2076(e)) for marketers and importers of self-pressurized consumer products... product stating that it contains a chlorofluorocarbon that may harm the public health and environment...

  8. Vital Signs.

    Science.gov (United States)

    Brown, Lester R.

    1993-01-01

    Presents an excerpt from the first edition of Vital Signs, a Worldwide Institute publication that provides an annual update on global environmental trends. Includes discussion of the dismantling of nuclear arms, reduction in chlorofluorocarbon production, growth in bicycle production, the decline in cigarette smoking, and decline in military…

  9. 21 CFR 801.63 - Medical devices; warning statements for devices containing or manufactured with...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical devices; warning statements for devices containing or manufactured with chlorofluorocarbons and other class I ozone-depleting substances. 801.63 Section 801.63 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES LABELING...

  10. Situation and perspectives in refrigerating and air-conditioning. The point of view of Elf Atochem; Situation et perspectives en refrigeration et air conditionne. Point de vue d`Elf Atochem

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This paper is a series of transparencies which explains the engagements of Elf Atochem company in the replacement of chlorofluorocarbons (CFCs): development of HFCs, production of FORANE, safety and environmental criteria, main refrigerants and their application in new installations, perspectives in reconversion, replacement of R-22, CFC-12 and R-502 fluids with respect to their applications. (J.S.)

  11. Demonstrating a Lack of Reactivity Using a Teflon-Coated Pan.

    Science.gov (United States)

    Richmond, Thomas G.

    1995-01-01

    Illustrates the chemical resistance of polytetrafluoroethene to mineral acids using an ordinary Teflon-coated frying pan. The demonstration can also be used to lead to a discussion of the long lifetimes of fluorocarbons and chlorofluorocarbons in the atmosphere and their roles in the breakdown of the ozone layer. (AIM)

  12. MODELING AND DESIGN STUDY USING HFC-236EA AS AN ALTERNATIVE REFRIGERANT IN A CENTRIFUGAL COMPRESSOR

    Science.gov (United States)

    The report gives results of an investigation of the operation of a centrifugal compressor--part of a chlorofluorocarbon (CFC)-114 chiller installation--with the new refrigerant hydrofluorocarbon (HFC)-236ea, a proposed alternative to CFC-114. A large set of CFC-236ea operating da...

  13. HEAT TRANSFER EVALUATION OF HFC-236EA AND CFC-114 IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). (NOTE: With the mandatory phase-out of chlorofluorocarbons (CFCs), as dictated by the Montreal Protocol and Clean Air Act Ame...

  14. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (...

  15. Ozone depletion and skin cancer incidence: an integrated modelling approach

    NARCIS (Netherlands)

    Slaper H; den Elzen MGJ; de Woerd HJ; de Greef J

    1992-01-01

    A decrease in stratospheric ozone, probably caused by chlorofluorocarbon (CFC) emissions, has been observed over large parts of the globe. The incidence of skin cancer is expected to increase due to ozone depletion. An integrated source-risk model is developed and applied to evaluate the increased

  16. The Hole in the Ozone Layer.

    Science.gov (United States)

    Hamers, Jeanne S.; Jacob, Anthony T.

    This document contains information on the hole in the ozone layer. Topics discussed include properties of ozone, ozone in the atmosphere, chlorofluorocarbons, stratospheric ozone depletion, effects of ozone depletion on life, regulation of substances that deplete the ozone layer, alternatives to CFCs and Halons, and the future of the ozone layer.…

  17. Extreme 13C depletion of CCl2F2 in firn air samples from NEEM, Greenland

    NARCIS (Netherlands)

    Zuiderweg, A.T.; Holzinger, R.; Röckmann, T.

    2012-01-01

    A series of 12 high volume air samples collected from the S2 firn core during the North Greenland Eemian Ice Drilling (NEEM) 2009 campaign have been measured for mixing ratio and stable carbon isotope composition of the chlorofluorocarbon CFC- 12 (CCl2F2). While the mixing ratio measurements compare

  18. Green Consciousness or Dollar Diplomacy? The British Response to the Threat of Ozone Depletion.

    Science.gov (United States)

    Maxwell, James H.; Weiner, Sanford L.

    1993-01-01

    Discusses the British role in the regulation of believed ozone-depleting substances such as chlorofluorocarbons. Recounts the history of the British policies during the emergence of the issue from 1974-80; a period of tactical resistance from 1980-87; and a change in policy from 1987-90. (66 references) (MDH)

  19. 78 FR 19801 - 2013 Revisions to the Greenhouse Gas Reporting Rule and Proposed Confidentiality Determinations...

    Science.gov (United States)

    2013-04-02

    ... EPA without going through http://www.regulations.gov your email address will be automatically captured... coal products. 316, 326, 339 Manufacturers of rubber and miscellaneous plastic products. 331 Steel... chlorofluorocarbon CFR Code of Federal Regulations CH 4 methane CO 2 carbon dioxide CO 2 e carbon dioxide...

  20. Exchangers: research axes for the future

    Energy Technology Data Exchange (ETDEWEB)

    Sartre, V.; Lallemand, M. (Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)); Marvillet, C. (CEA Centre d' Etudes de Grenoble, 38 (France))

    1993-11-01

    Energy consumption abatement (Greenhouse effect) and environment protection (Chlorofluorocarbons) are the two un-by-path axes for the development of refrigerating industry. Joule european research project aims to improve the performance of refrigerating machines. the present paper presents actual design and evolution of exchangers. 20 refs., 5 figs., 1 tab.

  1. Development of Cladding Materials for Evacuated Panel Superinsulation

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, K.E.; Weaver, F.J.; Cumberbatch, G.M.; Begnoche, B.; Brodie, V.; Lamb, W.; Reitz, R.; Caldwell, P.; Meyer, C.

    1999-11-01

    This Cooperative Research and Development Agreement (CRADA) was among E.I. DuPont de Nemours and Company, VacuPanel, Inc., and Lockheed Martin Energy Research Corp. Evacuated panel superinsulations have thermal resistivities (R) substantially above that of conventional existing insulation without the environmental problems of some insulations such as foam insulations blown with Chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).

  2. Synthetic greenhouse gases under control

    International Nuclear Information System (INIS)

    This article discusses new Swiss regulations on the use of synthetic materials that posses a considerable greenhouse-warming potential. Synthetic materials such as hydro-chlorofluorocarbons HCFCs, perfluoride-hydrocarbons and sulphur hexafluoride have, in recent years, replaced chlorofluorocarbons CFCs, which were banned on account of their ozone depletion characteristics. The use of these persistent substances is now being limited to applications where more environment-friendly alternatives are not available. The measures decreed in the legislation, which include a general ban on HCFCs as of 2004 and a ban on the export of installations and equipment that use ozone-depleting refrigerants are described. Details on the legislation's effects on the Swiss refrigeration industry are listed and discussed

  3. Upgrading of refrigeration units in nuclear power plant: An optimized approach to do justice to governmental restrictions

    International Nuclear Information System (INIS)

    Stringent regulations to reduce the use of chlorofluorocarbons (CFC) and halogenated chlorofluorocarbons (HCFC) have been set into force by many European countries. A ban for new plants containing HCFCs in 2005 and a total ban of HCFCs in 2020 are discussed within the European Community. Siemens-KWU and Sulzer Escher Wyss have developed a well-proofed procedure to solve the CFC problem for existing refrigeration systems in nuclear power plants. The new refrigerants are fluorinated hydrocarbons and for the centrifugal water chiller R134a is best suited. Prior to the market introduction toxicity, short and long term health effects, inflammability and stability of R134a have been investigated. The mechanical examination included wear, corrosion, lubrication and resistance to decomposition. A well-proven procedure was established which ensures the owner of the plant and the supplier best results

  4. Estudio y Modelado de una Bomba de Calor con CO2

    OpenAIRE

    Monticelli, Giuseppe

    2009-01-01

    CFCs (chlorofluorocarbons) have been abolished and HCFCs (hydrochlorofluorocarbons) are in process of being abolished as working fluids due to their high global warming potential (GWP) and ozone depletion potential (ODP). CO2 is non-toxic, non-flammable, has zero ODP and negligible GWP as working fluid. In the present work the behavior of transcritical CO2 from the point of view of its thermal and mechanical properties through the correlations of Gnielinski (1976), Pitla (2002)...

  5. Experimental Investigation and Mathematical Modeling of Commercially Available R744 Compressors

    OpenAIRE

    Kurtulus, Orkan; Olgun, Burak; Oguz, Emre

    2012-01-01

    The vapor compression cycle using refrigerant CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon) is widely used in refrigeration, air-conditioning and water heating industries. Utilization of these gases are prohibited by the Montreal Protocol. The critical temperature of carbon dioxide (CO2) is much lower than that of the other refrigerants, namely 31.06°C. The gas cooling process occurs at a constant pressure but at variable temperatures takes the place of the condensation process ...

  6. Catalytic Decomposition of CFC-12 over Heteropolyacids%杂多酸催化分解氟里昂-12

    Institute of Scientific and Technical Information of China (English)

    马臻; 华伟明; 唐颐; 高滋

    2000-01-01

    @@ Chlorine atoms from chlorofluorocarbons (CFCs) deplete stratospheric ozone and CFCs are green-house gases too. Owing to these environmental problems, many kinds of CFCs have been banned since the Montreal Protocol and two kinds of cleaning techniques have been developed. One is the synthesis of CFCs alternatives[1,2] and the other is the decomposition of banned CFCs in existing equipments[3,4].

  7. Pengetahuan, Sikap dan Tindakan Pemilik Bengkel AC Mobil Tentang Pemakaian CFC Sebagai Polutan Gas Rumah Kaca Pada Bengkel AC Mobil di Kelurahan Petisah Tengah Kecamatan Medan Petisah Tahun 2010.

    OpenAIRE

    Nasution, Gabriella Septiani

    2011-01-01

    Atmospheric temperature was determined by the levels of gases called green house gases that could cause the greenhouse effect causing global warming and ozone depletion. Chlorofluorocarbon (CFCs) was one type of greenhouse gases, one of which comes from automobile air conditioner servicing activities. This problem occurred since the use of air conditioner contained freon or refrigerant fake which is unsafe for environment and the occurrence of leaks in car air conditioning servicing process. ...

  8. Model calculations of the relative effects of CFCs and their replacements on stratospheric ozone

    Science.gov (United States)

    Fisher, Donald A.; Hales, Charles H.; Filkin, David L.; Ko, Malcolm K. W.; Sze, N. Dak

    1990-01-01

    Because chlorine has been linked to the destruction of stratospheric ozone, the use of many fully halogenated compounds, such as the chlorofluorocarbons CFC-11 and -12, is restricted by international agreement. Hydrohalocarbons are under intensive development as replacements for CFCs. Because they contain hydrogen, these gases are susceptible to tropospheric destruction which significantly shortens their atmospheric lifetimes,. Model calculations show that chlorine-containing hydrohalocarbons have less effect on ozone, by an order of magnitude, than their regulated counterparts.

  9. Thermal Decomposition of Lower-GWP Refrigerants

    OpenAIRE

    Ito, Makoto; Dang, Chaobin; Hihara, Eiji

    2014-01-01

    The use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) has been widely restricted. They have been replaced with hydrofluorocarbons (HFCs) in order to protect the ozone layer. However, the leakage of refrigerant into air from active or end-of-life air conditioners has been a serious environmental issue owing to the high global warming potential (GWP) of HFCs. It has therefore been widely recognized that the replacement of HFCs with lower-GWP refrigerants is a reasonable sol...

  10. Satellite observations of stratospheric hydrogen fluoride and comparisons with SLIMCAT calculations

    OpenAIRE

    Harrison, J. J.; Chipperfield, M. P.; C. D. Boone; Dhomse, S. S.; P. F. Bernath; Froidevaux, L.; Anderson, J.; J. Russell III

    2015-01-01

    The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Many of these fluorine-containing species deplete stratospheric ozone, and are regulated by the Montreal Protocol. Once in the atmosphere they slowly degrade, ultimately leading to the formation of HF, the dominant reservoir of stratospheric fluorine due to its extreme stability. Monitor...

  11. Neurotoxicity of 1-bromopropane: Evidence from animal experiments and human studies

    OpenAIRE

    Gaku Ichihara; Junzoh Kitoh; Weihua Li; Xuncheng Ding; Sahoko Ichihara; Yasuhiro Takeuchi

    2012-01-01

    1-Bromopropane was introduced as an alternative to ozone layer-depleting solvents such as chlorofluorocarbons and 1,1,1-trichloroethane. However, a dozen human cases have been reported with symptoms and signs of toxicity to 1-bromopropane including numbness, diminished vibration sense in the lower extremities as well as ataxic gait. An epidemiological study also demonstrated dose-dependent prolongation of distal latency and decrease in vibration sense in the lower extremities. The initial ani...

  12. Atmospheric Gas Tracers in Groundwater: Theory, Sampling. Measurement and Interpretation

    International Nuclear Information System (INIS)

    Some of the atmospheric gasses posses features that are sought in an environmental tracer of hydrogeologic interest. Among these, chlorofluorocarbons, sulfur hegzafluoride, carbon tetrachloride, methyl chloroform, krypton-85 etc. have found increasing use in groundwater age dating studies during the last ten years. This paper explains the theory of their use as tracer and discusses the major concerns as related to their sampling and analyses. Factors affecting their applicability and the approach to interpret tracer gas data is briefly outlined

  13. Metan v klimatickém systému

    OpenAIRE

    Zítková, Jana

    2014-01-01

    Methane is a gas that is the simplest saturated hydrocarbon. It belongs to the greenhouse gases, together with others such as carbon dioxide, water vapor, nitrous oxide and chlorofluorocarbons. These gases are due to their occurrence in the atmosphere capable to transmit shortwave radiation from the Sun towards the Earth, and on the contrary, can absorb long-wave radiation, which is emitted by the Earth and make itself and its surroundings warmer. This process, which causes a warming of the E...

  14. Transport and fate of trifluoroacetate in upland forest and wetland ecosystems

    OpenAIRE

    Likens, G. E.; Tartowski, S. L.; Berger, T. W.; Richey, D. G.; Driscoll, C. T.; Frank, H. G.; De Klein, A.

    1997-01-01

    Although trifluoroacetate (TFA), a breakdown product of chlorofluorocarbon replacements, is being dispersed widely within the biosphere, its ecological fate is largely unknown. TFA was added experimentally to an upland, northern hardwood forest and to a small forest wetland ecosystem within the Hubbard Brook Experimental Forest in New Hampshire. Inputs of TFA were not transported conservatively through these ecosystems; instead, significant amounts of TFA were retained within the vegetation a...

  15. Cleaning verification by air/water impingement

    Science.gov (United States)

    Jones, Lisa L.; Littlefield, Maria D.; Melton, Gregory S.; Caimi, Raoul E. B.; Thaxton, Eric A.

    1995-01-01

    This paper will discuss how the Kennedy Space Center intends to perform precision cleaning verification by Air/Water Impingement in lieu of chlorofluorocarbon-113 gravimetric nonvolatile residue analysis (NVR). Test results will be given that demonstrate the effectiveness of the Air/Water system. A brief discussion of the Total Carbon method via the use of a high temperature combustion analyzer will also be given. The necessary equipment for impingement will be shown along with other possible applications of this technology.

  16. What Could Be Causing Global Ozone Depletion

    Science.gov (United States)

    Singer, S. Fred

    1990-01-01

    The reported decline trend in global ozone between 1970 and 1986 may be in part an artifact of the analysis; the trend value appears to depend on the time interval selected for analysis--in relation to the 11-year solar cycle. If so, then the decline should diminish as one approaches solar maximum and includes data from 1987 to 1990. If the decline is real, its cause could be the result of natural and human factors other than just chlorofluorocarbons.

  17. Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability

    OpenAIRE

    Hassler, B.; Petropavlovskikh, I; J. Staehelin; August, T.; Bhartia, P. K.; Clerbaux, Cathy; Degenstein, D.; De Mazière, M.; DINELLI, B. M.; Dudhia, A.; Dufour, G.; Frith, S. M.; Froidevaux, L.; Godin-Beekmann, Sophie; Granville, J.

    2014-01-01

    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 ...

  18. Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability

    OpenAIRE

    Hassler, B.; Petropavlovskikh, I; J. Staehelin; August, T.; Bhartia, P. K.; Clerbaux, C.; Degenstein, D.; De Mazière, M.; DINELLI, B. M.; Dudhia, A.; Dufour, G.; Frith, S. M.; Froidevaux, L.; S. Godin-Beekmann; Granville, J.

    2014-01-01

    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 ch...

  19. Causes and impacts of changes in the stratospheric meridional circulation in a chemistry-climate model

    OpenAIRE

    Garny, Hella

    2010-01-01

    The climate of the stratosphere is known to be subject to long-term changes induced by anthropogenic emissions of long-lived greenhouse gases (GHGs) as well as by emissions of ozone depleting substances (primarily chlorofluorocarbons, CFCs). Enhanced concentrations of CFCs have led to strong ozone depletion over the last decades. Thanks to the Montreal Protocol and its amendments and adjustments, the stratospheric halogen loading is expected to retreat again in the future. Emis...

  20. Self-Calibrating, Variable-Flow Pumping System

    Science.gov (United States)

    Walls, Joe T.

    1994-01-01

    Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

  1. Catalytic fluorination s: the synthesis of hydro fluorocarbon (HFCs)

    International Nuclear Information System (INIS)

    Catalytic processes in the fluorine chemistry are developed for example in the selective preparation of substitutes of chlorofluorocarbons, such as the hydro-fluorocarbon CF3CH2F used as a refrigeration agent to replace the CF2CICCIF2. A better understanding of the catalyst and of the various mechanisms involved is required in order to increase the selectivity towards the wanted fluorinated products. (authors)

  2. Water and environment news. No. 2

    International Nuclear Information System (INIS)

    This issue of the bulletin lists projects in the IAEA's sub-programme Development and Management of Water Resources, presents plan of the IAEA Isotope Hydrology Section for the 1999-2000, reports on the activities of current co-ordinated research projects and technical co-operation projects. This publication also highlights some basic aspects of the measurement of chlorofluorocarbons; the use of oxygen and hydrogen isotopes for investigating past and current climate changes; exploration of geothermal resources in Asia

  3. Heat pumps and technological innovation: Civil use in 80's (2nd part)

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R. (Bari Univ. (Italy). Ist. di Fisica Tecnica ed Impianti Termotecnici)

    1990-10-01

    Absorption heat pumps have rapidly spread as prototypes in machines used over the year with an excellent power performance. Developments concerning engines are also interesting, mainly in the light of a fresh interest for the Stirling. Research in the field of substances is considerable, both to find more suitable substances from a thermodynamic point of view and to replace chlorofluorocarbons which endanger the ozone layer. Important developments have also occurred in the recovery of heat build-ups in the ground and in roofs as sources for heat pumps, whereas, in some countries, more attention is paid to the use of heat pumps for district heating.

  4. CONTRIBUTION A L’AMELIORATION DU SYSTEME DE CLIMATISATION DES VOITURES DE VOYAGEURS DE LA SNTF

    OpenAIRE

    YOUCEF, Ahmed

    2011-01-01

    L’accroissement de l’effet de serre et la diminution de la couche d’ozone ont marqué ces dix dernières années, les gaz frigorigènes classiques tels que les CFC (chlorofluorocarbones),HCFC (hydrochlorofluorocarbones) participent respectivement à la destruction de la couche d’ozone et à l’effet de serre. Les secteurs du froid et de la climatisation sont des domaines en pleine expansion non seulement dans les pays industrialisés mais aussi dans les pays en voie de développement. La communa...

  5. Synthesis of fluoropolymers in supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Fluoropolymers are used in many technologically demanding applications because of their balance of high-performance properties. A significant impediment to the synthesis of variants of commercially available amorphous fluoropolymers is their general insolubility in most solvents except chlorofluorocarbons (CFCs). The environmental concerns about CFCs can be circumvented by preparing these technologically important materials in supercritical fluids. The homogeneous solution polymerization of highly fluorinated acrylic monomers can be achieved in supercritical carbon dioxide by using free radical methods. In addition, detailed decomposition rates and efficiency factors were measured for azobisisobutyronitrile in supercritical carbon dioxide and were compared to those obtained with conventional liquid solvents

  6. Statement on global climate change before the Subcommittee on Energy and Power, United States House of Representatives

    International Nuclear Information System (INIS)

    Greenhouse gases are gases which are effectively transparent to incoming sunlight but absorb infrared radiation escaping to space and thereby warm the surface of the Earth. Human activities result in the release of greenhouse and related gases in such quantities that they are changing the composition of the atmosphere. Greenhouse and related gases which human activities release include carbon dioxide (CO2), methane (CH4) carbon monoxide (CO), nitrous oxide (N2O), nitrogen oxides (NOx), chlorofluorocarbons (CFCs) and sulphur dioxide (SO2). The emission and effects of these gases are detailed in this report

  7. Use of satellite data to constrain the model-calculated atmospheric lifetime for N2O - Implications for other trace gases

    Science.gov (United States)

    Ko, Malcolm K. W.; Sze, Nien Dak; Weisenstein, Debra K.

    1991-01-01

    Model calculations of the zonal-mean concentrations of N2O in the upper stratosphere are presented showing that about 80 percent of N2O is removed in the stratosphere between 30 deg N and 30 deg S. A comparison of calculated N2O values with remote data on N2O concentrations obtained from Nimbus 7 SAMS instrument indicated that the two-dimensional model of Ko and Sze (1982) may have underestimated the concentration of N2O in the tropical lower stratosphere. It is concluded that the calculated lifetimes for N2O and chlorofluorocarbon-source gases could be 30 percent shorter than previously reported values.

  8. The president speaks: prevention is best: lessons from protecting the ozone layer.

    Science.gov (United States)

    Woodcock, Ashley

    2012-12-01

    The Montreal Protocol was signed 25 years ago. As a result, the irreversible destruction of the ozone layer was prevented. However, stratospheric ozone will not recover completely until 2060 and the consequent epidemic in skin cancer cases will persist until 2100. Many millions of patients with asthma and chronic obstructive pulmonary disease have safely switched from chlorofluorocarbon (CFC)-powered metered-dose inhalers (MDIs) to either hydrofluorocarbon (HFC) or DPIs. China will be the last country to phase out CFCs by 2016. HFCs are global warming gases which will be controlled in the near future. HFCs in MDIs may be phased out over the next 10-20 years. PMID:23019254

  9. Updating hydrogen fluoride (HF) FTIR time series above Jungfraujoch: comparison of two retrieval algorithms and impact of line shape models

    OpenAIRE

    Duchatelet, Pierre; Demoulin, Philippe; Hase, Frank; Mahieu, Emmanuel; Bernath, Peter; Boone, Chris; Walker, Kaley

    2010-01-01

    Fluorine enters the stratosphere mainly in the form of chlorofluorocarbons (CFCs; principally CFC-11 and CFC-12) and tetrafluoromethane (CF4), which have been widely emitted at ground level by human activities over the past few decades. In the lower stratosphere, the photolysis of the long-lived CFC-11 (CCl3F) and CFC-12 (CCl2F2), whose emissions from the ground have been progressively phased out by the Montreal Protocol and its successive Amendments and Adjustments, leads to the formation of...

  10. Pilot retrofit test of refrigerant R-134a for GDSCC

    Science.gov (United States)

    Albus, J.; Brown, B.; Dungao, M.; Spencer, G.

    1994-01-01

    NASA has issued an interim policy requiring all of its Centers to eliminate consumption (purchase) of stratospheric ozone-depleting substances, including chlorofluorocarbons (CFC's), by 1995. Also, plans must be outlined for the eventual phase out of their usage. The greatest source of CFC consumption and usage at the Goldstone Deep Space Communications Complex is refrigerant R-12, which is used in many of the facility's air-conditioning systems. A pilot retrofit test shows that retrofitting R-12 air-conditioning systems with hydrofluorocarbon R-13a would be a workable means to comply with the R-12 portion of NASA's policy. Results indicate acceptable cost levels and nearly equivalent system performance.

  11. Greenhouse effect of trace gases, 1970-1980

    Science.gov (United States)

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

    1981-01-01

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

  12. Assessing the applicability of global CFC and SF6 input functions to groundwater dating in Britain

    International Nuclear Information System (INIS)

    Chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6) are increasingly being used to date groundwaters. While these trace gases are generally well-mixed in the atmosphere, local atmospheric excesses (LAEs) have been found in some parts of the world, thereby affecting the interpretation of data from groundwater studies. To investigate the possibility of LAEs in Britain, mixing ratios of CFC-11, CFC-12 and SF6 were measured in soil gases from two large conurbations (London and Birmingham) and a smaller urban area, Bristol. Most mixing ratios for CFC-12 and SF6 were 6 input functions based on the NH-AMR curves appears justified for Britain. (author)

  13. The president speaks: prevention is best: lessons from protecting the ozone layer.

    Science.gov (United States)

    Woodcock, Ashley

    2012-12-01

    The Montreal Protocol was signed 25 years ago. As a result, the irreversible destruction of the ozone layer was prevented. However, stratospheric ozone will not recover completely until 2060 and the consequent epidemic in skin cancer cases will persist until 2100. Many millions of patients with asthma and chronic obstructive pulmonary disease have safely switched from chlorofluorocarbon (CFC)-powered metered-dose inhalers (MDIs) to either hydrofluorocarbon (HFC) or DPIs. China will be the last country to phase out CFCs by 2016. HFCs are global warming gases which will be controlled in the near future. HFCs in MDIs may be phased out over the next 10-20 years.

  14. First retrievals of HCFC-142b from ground-based high resolution FTIR solar observations: application to high altitude Jungfraujoch spectra

    OpenAIRE

    Mahieu, Emmanuel; O'Doherty, Simon; REIMANN Stefan; Vollmer, Martin; Bader, Whitney; Bovy, Benoît,; Lejeune, Bernard; Demoulin, Philippe; Roland, Ginette; Servais, christian; Zander, Rodolphe

    2013-01-01

    Hydrofluorocarbons (HCFCs) are the first substitutes to the long-lived ozone depleting halocarbons, in particular the chlorofluorocarbons (CFCs). Given the complete ban of the CFCs by the Montreal Protocol, its Amendments and Adjustments, HCFCs are on the rise, with current rates of increase substantially larger than at the beginning of the 21st century. HCFC-142b (CH3CClF2) is presently the second most abundant HCFC, after HCFC-22 (CHClF2). It is used in a wide range of applications, includi...

  15. The Antarctic Ozone Hole: An Update

    Science.gov (United States)

    Douglass, Anne R.; Newman, Paul A.; Solomon, Susan

    2014-01-01

    The stratospheric ozone hole, an annual occurrence during austral spring, is caused by heterogeneous conversion of hydrogen chloride and chlorine nitrate to chlorine radicals. These reactions take place of polar stratospheric cloud particles in the cold, isolate Antarctic winter vortex. The chlorine radicals participate in chemical reactions that rapidly deplete ozone when sunlight returns at the end of polar night. International agreements eliminated production of the culprit anthropogenic chlorofluorocarbons in the late 1990s, but due to their long stratospheric lifetime (50-100 years), the ozone hole will continue its annual appearance for years to come.

  16. Study of groundwater mixing using CFC data

    Institute of Scientific and Technical Information of China (English)

    韩良丰; 庞忠和

    2001-01-01

    CFCs (Chlorofluorocarbons) are sensitive tools in the study of groundwater mixing. Based on results of CFC concentrations, the extent of mixing can be identified by three methods: 1. discrepancy between apparent ages determined by individual CFC compounds; 2. inconsistency between CFC concentration ratios and their respective apparent ages; and 3. correlation between the concentrations of two CFC compounds for a group of samples. The principle of determination of mixing ratios and apparent CFC water age in the case of a two component mixing of CFC-containing water with CFC-free water is described.

  17. Cleaning up our act: Alternatives for hazardous solvents used in cleaning

    International Nuclear Information System (INIS)

    Lawrence Livermore National Laboratory (LLNL) has studied more than 70 alternative cleaners as potential replacements for chlorofluorocarbons (CFCs), halogenated hydrocarbons (e.g., trichloroethylene and trichloroethane), hydrocarbons (e.g., toluene and Stoddard Solvent), and volatile organic compounds (e.g., acetone, alcohols). This report summarizes LLNL's findings after testing more than 45 proprietary formulations on bench-scale testing equipment and in more than 60 actual shops and laboratories. Cleaning applications included electronics fabrication, machine shops, optical lenses and hardware, and general cleaning. Most of the alternative cleaners are safer than the solvents previously used and many are nonhazardous, according to regulatory criteria

  18. Effects of injected ice particles in the lower stratosphere on the Antarctic ozone hole

    OpenAIRE

    Nagase, H.; Kinnison, D.; Petersen, A.; F. Vitt; Brasseur, G.

    2015-01-01

    The Antarctic ozone hole will continue to be observed in the next 35-50 years, although the emissions of chlorofluorocarbons (CFCs) have gradually been phased out during the last two decades. In this paper, we suggest a geo-engineering approach that will remove substantial amounts of hydrogen chloride (HCl) from the lower stratosphere in fall, and hence limit the formation of the Antarctic ozone hole in late winter and early spring. HCl will be removed by ice from the atmosphere at temperatur...

  19. Accelerated test methods for predicting the life of motor materials exposed to refrigerant/lubricant mixtures. Phase 1, Conceptual design: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II; Ferguson, A.

    1993-08-18

    The federally mandated phase-out of chlorofluorocarbon refrigerants requires screening tests for motor materials compatibility with alternative refrigerant/lubricant mixtures. In the current phase of the program, ARTI is supporting tests of promising candidate refrigeration/lubricant systems in key refrigeration component systems such as bearings and hermetic motor insulation systems to screen for more subtle detrimental effects and allow estimates of motor-compressor life. This report covers: mechanisms of failure of hermetic motor insulation, current methods for estimation of life of hermetic motors, and conceptual design of improved stator simulator device for testing of alternative refrigerant/lubricant mixtures.

  20. Global environmental report card

    Science.gov (United States)

    Showstack, Randy

    Worldwatch Institute, a Washington, D.C.-based think tank, issued a gloomy yet hopeful annual “State of the World” report on global environmental trends on 10 January.The report notes some recent successful efforts to protect the environment, including the phasing out of the production of ozone-depleting chlorofluorocarbons (CFCs) and the 2001 signing of the Stockholm Convention on Persistent Organic Pollutants (POPs). Nonetheless, the report calls for a global war on environmental degradation “that is as aggressive and well-funded as the war on terrorism” following the 11 September terrorist attacks in the United States.

  1. Cleaning up our act: Alternatives for hazardous solvents used in cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Shoemaker, J.D.; Meltzer, M.; Miscovich, D.; Montoya, D.; Goodrich, P.; Blycker, G.

    1994-01-01

    Lawrence Livermore National Laboratory (LLNL) has studied more than 70 alternative cleaners as potential replacements for chlorofluorocarbons (CFCs), halogenated hydrocarbons (e.g., trichloroethylene and trichloroethane), hydrocarbons (e.g., toluene and Stoddard Solvent), and volatile organic compounds (e.g., acetone, alcohols). This report summarizes LLNL`s findings after testing more than 45 proprietary formulations on bench-scale testing equipment and in more than 60 actual shops and laboratories. Cleaning applications included electronics fabrication, machine shops, optical lenses and hardware, and general cleaning. Most of the alternative cleaners are safer than the solvents previously used and many are nonhazardous, according to regulatory criteria.

  2. The practicalities of using CFCs and SF6 for groundwater dating and tracing

    OpenAIRE

    Darling, W.G.; Gooddy, D.C.; Macdonald, A. M.; Morris, B L

    2012-01-01

    Knowledge of groundwater residence time is important in understanding key issues in the evolution of water quality, whether this occurs due to water–rock interaction or simply by mixing or contamination. The build-up in the atmosphere of the trace gases chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6) from the middle of the last century offers a convenient way of dating waters up to ~60 yrs old. The gases are well-mixed in the atmosphere so their input functions are not area-specific...

  3. Stratospheric ozone depletion

    International Nuclear Information System (INIS)

    The amount of stratospheric ozone and the reduction of the ozone layer vary according to seasons and latitudes. At present total and vertical ozone is monitored over all Austria. The mean monthly ozone levels between 1994 and 2000 are presented. Data on stratospheric ozone and UV-B radiation are published daily on the home page http: www.lebesministerium.at. The use of ozone depleting substances such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) is provided. Besides, the national measures taken to reduce their use. Figs. 2, Tables 2. (nevyjel)

  4. Mesoporous Fluorinated Metal-Organic Frameworks with Exceptional Adsorption of Fluorocarbons and CFCs

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Jacobson, Allan J.; Miljani,; #263; Ognjen, Š. [NSRRC; (UC); (Houston)

    2016-02-08

    Two mesoporous fluorinated metal–organic frameworks (MOFs) were synthesized from extensively fluorinated tritopic carboxylate- and tetrazolate-based ligands. The tetrazolate-based framework MOFF-5 has an accessible surface area of 2445 m2g-1, the highest among fluorinated MOFs. Crystals of MOFF-5 adsorb hydrocarbons, fluorocarbons, and chlorofluorocarbons (CFCs)—the latter two being ozone-depleting substances and potent greenhouse species—with weight capacities of up to 225%. The material exhibits an apparent preference for the adsorption of non-spherical molecules, binding unusually low amounts of both tetrafluoromethane and sulfur hexafluoride.

  5. Ozone threat

    International Nuclear Information System (INIS)

    Ozone hole was first discovered in 1980. Thus 15 years even after the first warming, the world is no where near to the elimination of man made gases that threaten to destroy the ozone layer. Ozone depletion has become a matter of enormous threat which remains to be solved by the Scientists and intelligentia of the world. Ozone (O3) is a pungent poisonous gas. It forms a layer at a distance of about 15 miles above the earth's surface which helps shield living things from the sun shearing ultra violet light. If ozone is lost, more ultra violet light reaches the earth, which can lead to increasing rate of skin cancer, the death of micro organisms and the failure of crops and plants. It was in 1974 when it was discovered that Chlorofluorocarbons (CFCs) cold rise slowly to the upper atmosphere and destroy the earth's fragile ozone shield. Chlorofluorocarbons are commonly used as coolants (such as Freon) for home and automobile air conditioners and in the making of fast food containers. CFCs take about 100 years or more to reach he stratosphere to damage the ozone layers. In 1988, Scientists confirmed that upto 3% of the ozone layer over the more populated Northern Hemisphere has been destroyed. it is believed that for every 1% decrease in ozone, skin cancers are expected to rise 5 to 6 per cent due to the increase of ultraviolet light. Cases of cataracts and certain human immune system diseases are also expected to rise. (author)

  6. Issues and recommendations related to replacement of CFC-114 at the uranium enrichment gaseous diffusion plant

    International Nuclear Information System (INIS)

    The operating uranium enrichment gaseous diffusion plants (GDPs) in Portsmouth, Ohio and Paducah, Kentucky, which are operated for the United States Department for Energy by Martin Marietta Energy Systems (MMES), currently use a chlorofluorocarbon (CFC-114) as the primary process stream coolant. Due to recent legislation embodied in the Clean Air Act, the production of this and other related chlorofluorocarbons (CFCS) are to be phased out with no production occurring after 1995. Since the plants lose approximately 500,000 pounds per year of this process stream coolant through various leaks, the GDPs are faced with the challenge of identifying a replacement coolant that will allow continued operation of the plants. MMES formed the CFC Task Team to identify and solve the various problems associated with identifying and implementing a replacement coolant. This report includes a review of the work performed by the CFC Task Team, and recommendations that were formulated based on this review and upon original work. The topics covered include; identifying a replacement coolant, coolant leak detection and repair efforts, coolant safety concerns, coolant level sensors, regulatory issues, and an analytical decision analysis

  7. Matrix isolation model studies on the radiation-induced transformations of small molecules of astrochemical and atmospheric interest

    Science.gov (United States)

    Feldman, Vladimir I.; Ryazantsev, Sergey V.; Saenko, Elizaveta V.; Kameneva, Svetlana V.; Shiryaeva, Ekaterina S.

    2016-07-01

    The radiation-induced transformations of small molecules at low temperatures play an important role in the interstellar, planetary and atmospheric chemistry. This work presents a review of our recent model studies on the radiation chemistry of relevant molecules in solid noble gas (Ng) matrices, including some preliminary new results. Among the triatomic molecules, water and carbon dioxide were studied in detail. The radiation-induced degradation of isolated H2O yields hydrogen atoms and OH radicals, while oxygen atoms are produced at higher doses. Isolated CO2 molecules are decomposed to yield CO and trapped oxygen atoms. Upon annealing the trapped O and H atoms are mobilized selectively at different temperatures and react with other trapped species. The formation of HCO and HOCO radicals was observed in the mixed H2O/CO2/Ng systems. Other studies were concerned with the radiation-induced degradation of simple organic molecules (methanol, formic acid) and chlorofluorocarbons (CFCl3, CF2Cl2). Preliminary results for methanol revealed deep dehydrogenation yielding HCO and CO, whereas CO2, CO and HOCO were detected as primary products for formic acid. In the case of chlorofluorocarbons, significance of ionic channels was demonstrated. The implications of the results for modeling the processes in astrochemical ices and atmosphere are discussed.

  8. Analysis of Eco friendly Refrigerants Usage in Air-Conditioner

    Directory of Open Access Journals (Sweden)

    C. Chinnaraj

    2011-01-01

    Full Text Available Problem statement: There are two types of global warming contributions through refrigeration and air conditioning systems. The first one is the Direct Global Warming Potential (DGWP due to the emission of refrigerants and their interaction with heat radiation. The second one is the Indirect Global Warming Potential (IDGWP due to the emission of Carbon Dioxide (CO2 by consuming the energy that is generated through the combustion of fossil fuels. Most of refrigerants used in vapor Compression system were Chlorofluorocarbon (CFCs and Hydro Chlorofluorocarbon (HCFCs which contains chlorine and if any leakage in the system, these gases will go up and reach stratosphere. The chlorine atoms in the gases will act as a catalyst to destroy ozone layer and cause ozone depletion which causes health hazards, global warming, melting of polar ice caps and drought. Hence, it is necessary to minimize the Global warming and Ozone depletion. The refrigerant R22 widely used in the air-conditioners is a major Contributor of Chlorofluorocarbons (CFCs which cause irreparable loss to the ozone layer and has to be replaced. Approach: To conserve the energy and minimize the global warming, the systems should be designed as more energy efficient and also to minimize Ozone depletion, the eco friendly refrigerants are to be selected and tested as alternative refrigerants to R22. Hence, a window air conditioner of 3.5 kW capacity fitted with Electronic Expansion Valve (EEV instead of capillary tube as an expansion device, was tested for its performance with the selected eco friendly refrigerants R407C and R290 as an alternative to R22 under fixed indoor and outdoor chamber temperatures in the experimental set up and varying the EEV opening. Results: It has been observed from the experimental studies that when the smaller capacity R22 window air conditioner with EEV is retrofitted with R407C and R290, compared to the performance given by R22, the Coefficient Of Performance

  9. Shallow groundwater intrusion to deeper depths caused by construction and drainage of a large underground facility. Estimation using 3H, CFCs and SF6 as trace materials

    International Nuclear Information System (INIS)

    This study evaluates a method to estimate shallow groundwater intrusion in and around a large underground research facility (Mizunami Underground Research Laboratory-MIU). Water chemistry, stable isotopes (δD and δ18O), tritium (3H), chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) in groundwater were monitored around the facility (from 20 m down to a depth of 500 m), for a period of 5 years. The results show that shallow groundwater inflows into deeper groundwater at depths of between 200–400 m. In addition, the content of shallow groundwater estimated using 3H and CFC-12 concentrations is up to a maximum of about 50%. This is interpreted as the impact on the groundwater environment caused by construction and operation of a large facility over several years. The concomitant use of 3H and CFCs is an effective method to determine the extent of shallow groundwater inflow caused by construction of an underground facility. (author)

  10. Results of the Test Program for Replacement of AK-225G Solvent for Cleaning NASA Propulsion Oxygen Systems

    Science.gov (United States)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2016-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance chlorofluorocarbon-113 was banned, NASA's propulsion test facilities at Marshall Space Flight Center and Stennis Space Center have relied upon the solvent Asahiklin AK-225 (hydrochlorofluorocarbon-225ca/cb or HCFC-225ca/cb) and, more recently AK-225G (the single isomer form, HCFC-225cb) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of Class II Ozone Depleting Substances, including AK-225G, was prohibited in the United States by the Clean Air Act. In 2012 through 2014, NASA test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility collaborated to seek out, test, and qualify a solvent replacement for AK-225G that is both an effective cleaner and safe for use with oxygen systems. This paper summarizes the tests performed, results, and lessons learned.

  11. A multitracer approach for characterizing interactions between shallow groundwater and the hydrothermal system in the Norris Geyser Basin area, Yellowstone National Park

    Science.gov (United States)

    Gardner, W.P.; Susong, D.D.; Solomon, D.K.; Heasler, H.P.

    2011-01-01

    Multiple environmental tracers are used to investigate age distribution, evolution, and mixing in local- to regional-scale groundwater circulation around the Norris Geyser Basin area in Yellowstone National Park. Springs ranging in temperature from 3??C to 90??C in the Norris Geyser Basin area were sampled for stable isotopes of hydrogen and oxygen, major and minor element chemistry, dissolved chlorofluorocarbons, and tritium. Groundwater near Norris Geyser Basin is comprised of two distinct systems: a shallow, cool water system and a deep, high-temperature hydrothermal system. These two end-member systems mix to create springs with intermediate temperature and composition. Using multiple tracers from a large number of springs, it is possible constrain the distribution of possible flow paths and refine conceptual models of groundwater circulation in and around a large, complex hydrothermal system. Copyright 2011 by the American Geophysical Union.

  12. Atlantic CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    R. Steinfeldt

    2010-01-01

    Full Text Available Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic. In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC. The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl4. The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor'' quality flag.

  13. Combustibility Tests of 1,1,1,2-tetrafluoroethane in a Simulated Compressor Cylinder

    Science.gov (United States)

    Babcock, Dale A.; Bruce, Robert A.

    1997-01-01

    The advantages of high-molecular-weight gas (heavy gas) as a wind-tunnel medium have been recognized for some time. The current heavy gas of choice chlorofluorocarbon-12(CFC-12) (refrigerant R12) for the Transonic Dynamics Tunnel(TDT) must be replaced because manufacture of this gas ceased in 1995. An attractive replacement is 1,1,1,2-tetrafluoroethane (refrigerant R134a). Acceptable properties of this gas include molecular weight and speed of sound. Its vapor pressure allows simplified reclamation from mixtures with air. However, it is recognized that R134a is combustible under certain conditions of temperature, pressure, and concentration. A comprehensive study was conducted to identify those conditions and the influence of various parameters on the combustibility of the gas-air mixture.

  14. Experimental performance of ozone-safe alternative refrigerants: Experimental performance comparisons of R32, R125, R143a, R218, R134a, R152a, R124, R142b, RC318 and R143 in a refrigeration circuit

    Science.gov (United States)

    Sand, James R.; Vineyard, Edward A.; Nowak, Richard J.

    1990-02-01

    Several compounds proposed as near term or longer range substitutes for the regulated chlorofluorocarbon (CFC) refrigerants were tested in a breadboard vapor-compression circuit, and their performance was evaluated relative to more commonly used refrigerants. The limited physical property information available in the literature for these alternative compounds was used to fit an equation of state so coefficients of performance (COPs) and capacities calculated from refrigerant property subroutines could be compared to those obtained experimentally. Comparisons of measured and modeled performance are given for 11 alternatives and for R22, R12, and R114. Estimates of compressor efficiency with each refrigerant are provided. Several of the alternatives exhibited better performance than the more widely used refrigerants at some or all of the conditions tested. Ozone-safe, alternative refrigerants that performed better than CFC counterparts at selected conditions are R152a, R143a, R134a, R134, and R142b.

  15. Vocabulary of global warming. Vocabulaire du rechauffement climatique; Volume 1: Les agents a effet de serre

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, D.

    1992-01-01

    An English-French dictionary is presented of terminology relating to global warming. Terms are arranged in English alphabetical order, with explanatory notes and definitions in English and French; a cross-reference index of French terms gives their English equivalents. Examples of usage are also provided. The dictionary contains ca 6,000 terms, of which ca 1,250 are provided with definitions. The kinds of terms included are of the following four categories: contributors to the greenhouse effect, including carbon dioxide, chlorofluorocarbons, nitrogen oxides, methane, aerosols, and atmospheric water; radiation balance and albedo mechanisms; impacts on vegetation, water cycle, and living conditions; and related terminology such as found in the fields of paleoclimatology, palynology, geochronology, and mathematical modelling. The dictionary focuses on non-carbon dioxide greenhouse gases since the terminology for carbon dioxide is relatively stable while that related to non-carbon dioxide gases is as yet little known and rapidly evolving. 110 refs.

  16. Human activities affecting trace gases and climate

    International Nuclear Information System (INIS)

    The Earth's climate has been in a constant state of change throughout geologic time due to natural perturbations in the global geobiosphere. However, various human activities have the potential to cause future global warming over a relatively short amount of time. These activities, which affect the Earth's climate by altering the concentrations of trace gases in the atmosphere, include energy consumption, particularly fossil-fuel consumption; industrial processes (production and use of chlorofluorocarbons, halons, and chlorocarbons, landfilling of wastes, and cement manufacture); changes in land use patterns, particularly deforestation and biomass burning; and agricultural practices (waste burning, fertilizer usage, rice production, and animal husbandry). Population growth is an important underlying factor affecting the level of growth in each activity. This paper describes how the human activities listed above contribute to atmospheric change, the current pattern of each activity, and how levels of each activity have changed since the early part of this century

  17. Climate Impact of Solar Variability

    Science.gov (United States)

    Schatten, Kenneth H. (Editor); Arking, Albert (Editor)

    1990-01-01

    The conference on The Climate Impact of Solar Variability, was held at Goddard Space Flight Center from April 24 to 27, 1990. In recent years they developed a renewed interest in the potential effects of increasing greenhouse gases on climate. Carbon dioxide, methane, nitrous oxide, and the chlorofluorocarbons have been increasing at rates that could significantly change climate. There is considerable uncertainty over the magnitude of this anthropogenic change. The climate system is very complex, with feedback processes that are not fully understood. Moreover, there are two sources of natural climate variability (volcanic aerosols and solar variability) added to the anthropogenic changes which may confuse our interpretation of the observed temperature record. Thus, if we could understand the climatic impact of the natural variability, it would aid our interpretation and understanding of man-made climate changes.

  18. Transport and reaction processes affecting the attenuation of landfill gas in cover soils

    DEFF Research Database (Denmark)

    Molins, S.; Mayer, K.U.; Scheutz, Charlotte;

    2008-01-01

    of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate, the contributions of various gas transport processes on methane attenuation in landfill cover soils...... to the atmosphere. Oxygen supply into the soil column is driven exclusively by diffusion, whereas advection outward offsets part of the diffusive contribution. In the reaction zone, methane consumption reduces the pressure gradient, further decreasing the significance of advection near the top of the column......Methane and trace organic gases produced in landfill waste are partly oxidized in the top 40 cm of landfill cover soils under aerobic conditions. The balance between the oxidation of landfill gases and the ingress of atmospheric oxygen into the soil cover determines the attenuation of emissions...

  19. [Climatic changes in Scandinavia--consequences for public health].

    Science.gov (United States)

    Kanestrøm, I

    1999-01-30

    Atmospheric composition and climate conditions are of great importance for health. Increasing consumption of fossil fuels ever since the industrial revolution has resulted in higher contents of greenhouse gases in the atmosphere. Primarily, this will increase the global temperature. Secondarily, it may change the patterns of precipitation and droughts. Higher extreme temperatures will have a negative effect on health. Climate changes can also change the living conditions of undesirable insects and microbes. The ozone gas in the atmosphere acts as a shield against the harmful ultraviolet radiation from the sun. Chlorofluorocarbons contribute to reduction of the ozone layer and increase ultraviolet radiation. Increased exposure of the skin to this radiation may cause damage such as sunburn and skin cancer. In order to avoid damage, it is of importance to wear protective clothing or use effective sunshades.

  20. DETECTING INDUSTRIAL POLLUTION IN THE ATMOSPHERES OF EARTH-LIKE EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Henry W. [Harvard College, Cambridge, MA 02138 (United States); Abad, Gonzalo Gonzalez; Loeb, Abraham, E-mail: henrylin@college.harvard.edu, E-mail: ggonzalezabad@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2014-09-01

    Detecting biosignatures, such as molecular oxygen in combination with a reducing gas, in the atmospheres of transiting exoplanets has been a major focus in the search for alien life. We point out that in addition to these generic indicators, anthropogenic pollution could be used as a novel biosignature for intelligent life. To this end, we identify pollutants in the Earth's atmosphere that have significant absorption features in the spectral range covered by the James Webb Space Telescope. We focus on tetrafluoromethane (CF{sub 4}) and trichlorofluoromethane (CCl{sub 3}F), which are the easiest to detect chlorofluorocarbons (CFCs) produced by anthropogenic activity. We estimate that ∼1.2 days (∼1.7 days) of total integration time will be sufficient to detect or constrain the concentration of CCl{sub 3}F (CF{sub 4}) to ∼10 times the current terrestrial level.

  1. 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. PMID:25706493

  2. Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigeration for lesser developed countries

    Science.gov (United States)

    Erickson, Donald C.

    1990-02-01

    The Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigerator is a solar thermal technology which provides low cost, efficient, reliable ice-making to areas without ready access to electricity. An ISAAC refrigeration system consists of a compound parabolic solar collector, two pressure vessels, a condenser, a cold box or refrigerated space, and simple connective piping -- no moving parts or electrical components. Most parts are simple construction or plumbing grade materials, locally available in many remote areas. This technology has numerous potential benefits in lesser developed countries both by providing a cheap, reliable source of ice, and, since manufacture requires only semi-skilled labor, a source of employment to the local economy. Applications include vaccine storage for health care clinics; fish, meat, and dairy product storage; and personal consumption. Importantly, this technology increases the quality of life for people in lesser developed countries without depleting fossil fuel resources or increasing the release of greenhouse gases such as CO2 and chlorofluorocarbons.

  3. Compounds produced by motor burnouts of refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Koester, C.; Hawley-Fedder, R.; Foiles, L.

    1995-05-24

    The phase-out of chlorofluorocarbons has necessitated the introduction of alternate refrigerants. R22 (CF{sub 2}ClH), R134a (CF{sub 3}CH{sub 2}F), and R507 (50/50 CHF{sub 2}CF{sub 3}/CF{sub 3}CH{sub 3}) are newer fluids which are used in cooling systems. Recently, concern over the possible formation of toxic compounds during electrical arcing through these fluids has prompted us to identify their electrical breakdown products by electron ionization GC/MS. For example, it is known that perfluoroisobutylene (PFIB), which have an threshold limit value of 10 ppb (set by the American Conference of Government Industrial Hygienists), is produced from the thermal and electrical breakdown of some refrigerants. We have used specially designed test cells, equipped with electrodes, to simulate the electrical breakdown of R22, R134a, and R507 in refrigeration systems.

  4. Pollution prevention and waste minimization tools workshops: Proceedings. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    The purpose of the second workshop was to bring together representatives of DOE and DOE contractor organizations to discuss four topics: process waste assessments (PWAs), a continuation of one of the sessions held at the first workshop in Clearwater; waste minimization reporting requirements; procurement systems for waste minimization; and heating, ventilating, and air conditioning (HVAC) and replacements for chlorofluorocarbons (CFCs). The topics were discussed in four concurrent group sessions. Participants in each group were encouraged to work toward achieving two main objectives: establish a ``clear vision`` of the overall target for their session`s program, focusing not just on where the program is now but on where it should go in the long term; and determine steps to be followed to carry out the target program.

  5. Emergence of healing in the Antarctic ozone layer

    Science.gov (United States)

    Solomon, Susan; Ivy, Diane J.; Kinnison, Doug; Mills, Michael J.; Neely, Ryan R.; Schmidt, Anja

    2016-07-01

    Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically driven increase in polar ozone (or “healing”) is expected in response to this historic agreement. Observations and model calculations together indicate that healing of the Antarctic ozone layer has now begun to occur during the month of September. Fingerprints of September healing since 2000 include (i) increases in ozone column amounts, (ii) changes in the vertical profile of ozone concentration, and (iii) decreases in the areal extent of the ozone hole. Along with chemistry, dynamical and temperature changes have contributed to the healing but could represent feedbacks to chemistry. Volcanic eruptions have episodically interfered with healing, particularly during 2015, when a record October ozone hole occurred after the Calbuco eruption.

  6. Atmospheric CO2: principal control knob governing Earth's temperature.

    Science.gov (United States)

    Lacis, Andrew A; Schmidt, Gavin A; Rind, David; Ruedy, Reto A

    2010-10-15

    Ample physical evidence shows that carbon dioxide (CO(2)) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO(2), like ozone, N(2)O, CH(4), and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO(2) and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state. PMID:20947761

  7. Efforts to reduce stratospheric ozone loss affect agriculture

    International Nuclear Information System (INIS)

    Research has shown that the increased ultraviolet radiation reaching the Earth's surface resulting from stratospheric ozone loss poses a danger to everyone. Concern about ozone loss prompted many nations to ratify the Montreal Protocol, the most comprehensive international environmental agreement ever enacted. Several provisions of this protocol will have substantial, long-term effects on the agricultural industry. Agriculture contributes substantially to ozone depletion, primarily through its use of chlorofluorocarbons (CFCs) for refrigeration in processing, storage and transport of meats and produce. This paper is meant to serve as an overview of the scientific basis for ozone depletion concerns, a description of the current international policy agreement, and the possible consequences of that policy for agriculture. (author)

  8. 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...

  9. Management of C&D waste from generation to final sink - do we forget the volatile harmful substances?

    DEFF Research Database (Denmark)

    Kjeldsen, Peter

    extremely slowly during use. Therefore, the insulation material will still contain large quantities of CFC when the buildings reach the endof-life and are demolished. The management of C&D waste in relation to controlling the CFC releases is basically unregulated in contrast to end-of-life refrigerators...... also containing large quantities of CFC in the insulation material. In the future, the development of new management strategies are highly needed because the quantities of C&D waste containing CFCs will increase. Strategies should focus on minimizing CFC releases during demolishing and recycling......Large quantities of construction and demolition waste (C&D waste) are produced. Buildings in many countries are thermally insulated by insulation foam containing large amounts of CFCs (chlorofluorocarbons), which are both strong ozone depleting substances and greenhouse gases. The CFCs are released...

  10. Attenuation of fluorocarbons released from foam insulation in landfills

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Dote, Yukata; Fredenslund, Anders Michael;

    2007-01-01

    Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) have been used as blowing agents (BAs) for foam insulation in home appliances and building materials, which after the end of their useful life are disposed of in landfills. The objective of this project...... in any of the experiments within a run time of up to 200 days. The obtained degradation rate coefficients were used as input for an extended version of an existing landfill fate model incorporating a time dependent BA release from co-disposed foam insulation waste. Predictions with the model indicate...... was to evaluate the potential for degradation of BAs in landfills, and to develop a landfill model, which could simulate the fate of BAs in landfills. The investigation was performed by use of anaerobic microcosm studies using different types of organic waste and anaerobic digested sludge as inoculum. The BAs...

  11. Guidelines on reducing atmospheric emissions from oil and gas facilities

    International Nuclear Information System (INIS)

    These guidelines have been produced by the United Kingdom Offshore Operators Association (UKOOA) to assist operators in improving emissions performance in the upstream oil and gas industry. The principal environmental concerns relevant to activities within the industry are: global climate change which could result from carbon dioxide and methane emissions; stratospheric ozone depletion caused by halons and chlorofluorocarbons; ground level ozone formation from reactions between volatile organic compounds and oxides of nitrogen; acidification caused by gases such as oxides of nitrogen and sulphur. The guidelines are set out under the following main areas: environmental concerns and legislative responses; atmospheric emissions sources; facility design for improved performance; improving performance of existing operations; cost-effectiveness of air emission reduction projects. (UK)

  12. Ozone Hole Over Antarctica

    Science.gov (United States)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  13. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Thomas G. Thompson Cruise in the Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Sabine, C.L.; Key, R.M.; Hall, M.; Kozyr, A.

    1999-08-01

    This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO2), total alkalinity (TALK), and radiocarbon (delta 14C), at hydrographic stations, as well as the underway partial pressure of CO2 (pCO2) during the R/V Thomas G. Thompson oceanographic cruise in the Pacific Ocean (Section P10). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Suva, Fiji, on October 5, 1993, and ended in Yokohama, Japan, on November 10, 1993. Measurements made along WOCE Section P10 included pressure, temperature, salinity [measured by conductivity temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO2, TALK, delta 14C, and underway pCO2.

  14. DETECTING INDUSTRIAL POLLUTION IN THE ATMOSPHERES OF EARTH-LIKE EXOPLANETS

    International Nuclear Information System (INIS)

    Detecting biosignatures, such as molecular oxygen in combination with a reducing gas, in the atmospheres of transiting exoplanets has been a major focus in the search for alien life. We point out that in addition to these generic indicators, anthropogenic pollution could be used as a novel biosignature for intelligent life. To this end, we identify pollutants in the Earth's atmosphere that have significant absorption features in the spectral range covered by the James Webb Space Telescope. We focus on tetrafluoromethane (CF4) and trichlorofluoromethane (CCl3F), which are the easiest to detect chlorofluorocarbons (CFCs) produced by anthropogenic activity. We estimate that ∼1.2 days (∼1.7 days) of total integration time will be sufficient to detect or constrain the concentration of CCl3F (CF4) to ∼10 times the current terrestrial level

  15. Electrostatic charges generated on aerosolisation of dispersions

    CERN Document Server

    Wang, Y

    2001-01-01

    In responding to the international community's agreement of phasing out chlorofluorocarbon (CFC) propellants by the year 2000, hydrofluoroalkane (HFA) has been chosen to replace CFCs. Intensive investigations related to the new propellant products have been carried out. Aerosol electrostatics is one of the topics investigated. To understand and subsequently control the charging processes is the motive of the research reported here. To help elucidate the complex charging process occurring naturally during atomization of liquids from pressurised Metered Dose Inhalers (pMDIs), it has been broken down into a sequence of related, simpler sub processes-drop charging, streaming current charging (coarse spray), splashing charging and fine spray charging. Our initial studies are of single drops forming at and breaking away from the tips of capillary tubes. The drop forming processes are so slow that any hydrodynamic effect can be dismissed. Then the charge on the drop is measured. It is found that the charge on water ...

  16. The stratospheric ozone hole a man-caused chemical instability

    CERN Document Server

    Crutzen, P J

    1997-01-01

    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 worse.

  17. 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.

  18. The Ozone Layer and Metered Dose Inhalers

    Directory of Open Access Journals (Sweden)

    Louis-Philippe Boulet

    1998-01-01

    Full Text Available The stratospheric ozone layer plays a crucial role in protecting living organisms against ultraviolet radiation. Chlorofluorocarbons (CFC contained in metered-dose inhalers (MDIs contribute to ozone depletion and in accordance with the Montreal Protocol on Substances That Deplete the Ozone Layer established 10 years ago, phase-out strageies have been developed worldwide for this category of agents. Alternatives to CFC-containing inhalers have been developed, such as powder inhalers and those using hydrofluoroalkanes (HFAs as propellants, which have been shown to be as safe and effective as CFC-containing inhalers and even offer interesting advantages over older inhalers. The transition to non-CFC MDIs requires a major effort to make the new products available and to ensure adequate comparision with the previous ones. It also requires a harmonization of actions taken by industry, government, licencing bodies and patients or health professional associations to ensure adequate information and education to the public and respiratory care providers.

  19. 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.

  20. Toxicology evaluation and hazard review for non-CFC containing rigid foams BKC 44317 and last-a-foam MSL-02A

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, K.A.; Archuleta, M.M.

    1996-06-01

    New pour-in-place, low density, rigid polyurethane foam kits have been developed to mechanically stabilize damaged explosive ordnance. Although earlier foam systems used chlorofluorocarbons as blowing agents, the current versions rely on carbon dioxide generated by the reaction of isocynates with water. In addition, these kits were developed to manually generate small quantifies of rigid foam in the field with minimal or no protective equipment. The purpose of this study was to evaluate and summarize available hazard information for the components of these rigid foam kits and to provide recommendations for personal protective equipment to be used while performing the manual combination of the components. As with most rigid foam systems, these kits consist of two parts, one a mixture of isocyanates; the other, a combination of polyols, surfactants, and amine catalysts. Once completely deployed, the rigid foam is non-toxic. The components, however, have some important health effects which must be considered when establishing handling procedures.

  1. Climate action. What can be done to fight the ozone hole and greenhouse effect. Klima Aktionsbuch. Was tun gegen Ozonloch und Teibhauseffekt

    Energy Technology Data Exchange (ETDEWEB)

    Blanck, K.; Matzen, D.; Schott, P.; Wiegand, J. (Robin Wood, Bremen (Germany). Arbeitskreis Ozon)

    1990-10-01

    The greenhouse effect is caused by an increase in gases that bear on climate - carbon dioxide, methane, and nitrous oxide. They stem mainly from combustion processes, for instance in automobile engines, power plants and heatings, the burning down of tropical forests, and intensive farming. Chapter 1 explains these relationships in detail, while chapters 2 and 3 are concerned with who causes these increases in trace gases as well as with possible countermeasures in the sectors of energy and transport. The contribution of tropical deforestation to the climate catastrophe is explained in chapter 4. Responsible for the thinning of the ozone layer at the altitude of 15 to 30 kilometres, which protects us from excessive UV radiation, is a group of gases containing chlorine and which are known as chlorofluorocarbons. What is less widely known are their many every-day uses, which are more closely dealt with in chapter 5. (orig./KW).

  2. The 1997 spectroscopic GEISA databank.

    Science.gov (United States)

    Jacquinet-Husson, N.; Arie, E.; Ballard, J.; Barbe, A.; Bjoraker, G.; Bonnet, B.; Brown, L. R.; Camy-Peyret, C.; Champion, J. P.; Chedin, A.; Chursin, A.; Clerbaux, C.; Duxbury, G.; Flaud, J.-M.; Fourrie, N.; Fayt, A.; Graner, G.; Gamache, R.; Goldman, A.; Golovko, V.; Guelachvili, G.; Hartmann, J. M.; Hilico, J. C.; Hillman, J.; Lefevre, G.; Lellouch, E.; Mikhailenko, S. N.; Naumenko, O. V.; Nemtchinov, V.; Newnham, D. A.; Nikitin, A.; Orphal, J.; Perrin, A.; Reuter, D. C.; Rinsland, C. P.; Rosenmann, L.; Rothman, L. S.; Scott, N. A.; Selby, J.; Sinitsa, L. N.; Sirota, J. M.; Smith, A. M.; Smith, K. M.; Tyuterev, V. G.; Tipping, R. H.; Urban, S.; Varanasi, P.; Weber, M.

    1999-05-01

    The current version GEISA-97 of the computer-accessible database system GEISA (Gestion et Etude des Informations Spectroscopiques Atmospheriques: Management and Study of Atmospheric Spectroscopic Information) is described. This catalogue contains 1,346,266 entries. These are the spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located between 0 and 22656 cm-1. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the giant planets. GEISA-97 contains also a catalog of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. The modifications and improvements made to the earlier edition (GEISA-92) and the data management software are described.

  3. GEISA-97 spectroscopic database system related information resources: current status and perspectives

    Science.gov (United States)

    Chursin, Alexei A.; Jacquinet-Husson, N.; Lefevre, G.; Scott, Noelle A.; Chedin, Alain

    2000-01-01

    This paper presents the recently developed information content diffusion facilities, e.g. the WWW-server of GEISA, MS DOS, WINDOWS-95/NT, and UNIX software packages, associated with the 1997 version of the GEISA-(Gestion et Etude des Informations Spectroscopiques Atmospheriques; word translation: Management and Study of Atmospheric Spectroscopic Information) infrared spectroscopic databank developed at LMD (Laboratoire de Meteorologie Dynamique, France). GEISA-97 individual lines file involves 42 molecules (96 isotopic species) and contains 1,346,266 entries, between 0 and 22,656 cm-1. GEISA-97 also has a catalog of cross-sections at different temperatures and pressures for species (such as chlorofluorocarbons) with complex spectra. The current version of the GEISA-97 cross- section databank contains 4,716,743 entries related to 23 molecules between 555 and 1700 cm-1.

  4. Climate change: Problems of limits and policy responses

    International Nuclear Information System (INIS)

    Present emission rates of carbon dioxide (CO2) and the other principle greenhouse gases (radiatively important gases (RIG's)) - methane, nitrous oxide, and chlorofluorocarbons - exceed the capacity of the oceanic, terrestrial, and tropospheric sinks to absorb them. Consequently, their concentrations in the troposphere are increasing and will continue to increase so long as emissions exceed sink capacities. It is assumed that an indefinitely persistent gap between emissions and sinks of RIG's implies indefinite global warming and related changes in regional climates. The high monetary and environmental costs that would be imposed by global warming are discussed along with the changes in energy policy that are needed to insure that these high costs will not be past on to future generations

  5. Tropospheric reactions of the haloalkyl radicals formed from hydroxyl radical reaction with a series of alternative fluorocarbons

    Science.gov (United States)

    Atkinson, Roger

    1990-01-01

    In the present assessment, the hydrogen containing halocarbons being considered as alternatives to the the presently used chlorofluorocarbons are the hydrochlorofluorocarbons (HCFCs) 123 (CF3CHCl2), 141b (CFCl2CH3), 142b (CF2ClCH3), 22 (CHF2Cl) and 124 (CF3CHFCl) and the hydrofluorocarbons (HFCs) 134a (CF3CH2F), 152a (CHF2CH3) and 125 (CF3CHF2). All of these HCFCs and HFCs will react with the hydroxyl (OH) radical in the troposphere, giving rise to haloalkyl radicals which then undergo a complex series of reactions in the troposphere. These reactions of the haloalkyl radicals formed from the initial OH radical reactions with the HCFCs and HFCs under tropospheric conditions are the focus here.

  6. Between prohibition and proof of need

    International Nuclear Information System (INIS)

    This article discusses the consequences of new Swiss legislation on the use of chloro-fluoro-carbons (CFC) in refrigeration and air-conditioning units. In particular, the initial replacement of refrigerants that deplete the ozone layer with CFC products is discussed and the climate warming issues associated with global warming potential of these CFCs are examined. The measures set out in the new materials decree that bans substances with a long-term stability in certain appliances and that demands the adherence to the newest technical standards for operation and maintenance are described. The options of refraining from using cooling apparatus at all or the use of other possible solutions for meeting cooling needs using natural working fluids are discussed and the associated problems are discussed. The article is completed with a table giving figures on ecological impact of various substances and a summary of current regulations

  7. Potential CFC replacements: Tropospheric lifetimes of C 3 hydrofluorocarbons and hydrofluoroethers

    Science.gov (United States)

    Cooper, David L.; Cunningham, Terry P.; Allan, Neil L.; McCulloch, Archie

    Attack by tropospheric hydroxyl radicals results in much shorter residence times for hydrofluorocarbons (HFCs) than for the fully halogenated chlorofluorocarbons (CFCs). Empirical structure-activity relations, previously calibrated for HFCs containing two carbon atoms, are used with semi-empirical and ab initio calculations to provide realistic first estimates of tropospheric lifetimes of various chlorine-free HFCs and hydrofluoroethers (HFEs) containing three carbon atoms. The heavily fluorinated HFEs are of particular interest in that they are likely to possess thermophysical properties which are suited to a range of applications for which CFCs are currently employed. Many of the HFEs are predicted to have shorter lifetimes than HFC-134a (CF 3CH 2F), which is already in large-scale commercial production as an alternative refrigerant. Factors are identified which appear to favour short lifetimes for HFEs.

  8. Global warming implications of replacing CFCs

    International Nuclear Information System (INIS)

    The late 1980s were a challenging time for the HVAC and R industries because of the demands being made for increased energy efficiency, the development of alternative refrigerants that do not destroy stratospheric ozone, and the intense pressures of international competition. The 1990s will not be any less demanding, with further requirements to improve efficiency and changing understandings of environmental acceptability. Dealing with the global warming issue creates further difficulties in adapting the refrigeration and insulation technologies for future needs as chlorofluorocarbons are phased out of production and use in accordance with the Montreal Protocol. The study reported in this article was conducted to help industry, government and international policymakers reach sound decisions during the change-over from the CFCs to alternative compounds and technologies. Information developed in this effort complements ongoing studies to assess safety, toxicology, cost and other factors influencing these decisions

  9. Air-Sea Interactions of Natural Long-Lived Greenhouse Gases (CO2, N2O, CH4) in a Changing Climate

    Digital Repository Service at National Institute of Oceanography (India)

    Bakker, D.C.E.; Bange, H.W.; Gruber, N.; Johannessen, T.; Upstill-Goddard, R.C.; Borges, A.V.; Delille, B.; Loscher, C.R.; Naqvi, S.W.A.; Omar, A.M.; Santana-Casiano, J.M.

    in chlorofluorocarbon (CFC) emissions, N2O may soon replace CFCs as the fourth most impor- tant greenhouse gas after water vapour (H2O), CO2 and CH4 (Forster et al. 2007). The major sink of N2O is Box 3.1 Atmospheric gases are quantified by their dry mole fraction... forcings (RF) and lifetimes (adjustment time) of CO2, N2O and CH4 (After Forster et al. 2007; WDCGG 2012) Gas Abundance in 2010 Abundance in 2005 RF in 2005 (W m�2) Lifetime (years) CO2 389.0 ppm 379 � 0.65 ppm 1.66 See belowa N2O 323.2 ppb 319 � 0.12 ppb 0...

  10. Viscosity Measurements of Ethyl Fluoride (R161) from 243 K to 363 K at Pressures up to 30 MPa

    Science.gov (United States)

    Meng, Xianyang; Gu, Xiaoyun; Wu, Jiangtao; Bi, Shengshan

    2015-11-01

    The Montreal Protocol and its subsequent amendments have created a schedule to replace ozone depletion substances, such as chlorofluorocarbons and hydrochlorofluorocarbons, with chlorine-free molecules in several industrial applications. Ethyl fluoride (R161, C2H5F, 353-36-6) was found to be a potential alternative refrigerant for the replacement of controlled substances, such as R22 with excellent cycle performance. In this work, the viscosity of ethyl fluoride is reported at temperatures from 243 K to 363 K and at pressures from saturation pressure to 30 MPa. The experiment was performed with a calibrated vibrating-wire viscometer, which exhibited a combined expanded uncertainty of 2.5 % with a level of confidence of 0.95 (k = 2) for such a fluid. A scheme based on a hard-spheres model was used to correlate the experimental results. The average absolute deviation of the experimental results from the correlations for R161 is 0.88 %.

  11. Electron-induced hydrogen loss in uracil in a water cluster environment

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, M.; Kohanoff, J. [Atomistic Simulation Centre, Queen' s University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom); Fabrikant, I. I., E-mail: ifabrikant1@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA and Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2014-05-14

    Low-energy electron-impact hydrogen loss due to dissociative electron attachment (DEA) to the uracil and thymine molecules in a water cluster environment is investigated theoretically. Only the A{sup ′}-resonance contribution, describing the near-threshold behavior of DEA, is incorporated. Calculations are based on the nonlocal complex potential theory and the multiple scattering theory, and are performed for a model target with basic properties of uracil and thymine, surrounded by five water molecules. The DEA cross section is strongly enhanced when the attaching molecule is embedded in a water cluster. This growth is due to two effects: the increase of the resonance lifetime and the negative shift in the resonance position due to interaction of the intermediate negative ion with the surrounding water molecules. A similar effect was earlier found in DEA to chlorofluorocarbons.

  12. Groundwater chemical methods for recharge studies. The basic of recharge and discharge. Part 2

    International Nuclear Information System (INIS)

    Groundwater chemical methods for estimating recharge can provide useful information on groundwater sources and the location of major recharge areas. Two geochemical approaches that have been used successfully to quantify groundwater recharge rates are outlined. The first involves the use of mass balance and mixing cell models, mainly using conservative (non-reacting) dissolved species (3H, 2H, 18O, chloride). The methods range in complexity from simple calculations ( zero-dimensional chloride mass balance) to complex three-dimensional computer models. The second approach seeks to estimate the age or residence time of the groundwater by measuring compounds which are radioactive (14C) or whose input to the aquifer has been changing over time (chlorofluorocarbons). The methodology and some case studies are described. (authors)

  13. Needs of thermodynamic properties measurements and modeling in the frame of new regulations on refrigerants

    Institute of Scientific and Technical Information of China (English)

    COQUELET Christophe; RICHON Dominique

    2007-01-01

    In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. Unfortunately,HFCs have non negligible global warning potential and therefore new refrigerants must be proposed or old refrigerants must be used associated with HFC. Accurate experimental thermodynamic data and predictive techniques are required for better understanding of the performance of the newly proposed refrigerants. In this communication, experimental techniques based on either analytic or synthetic methods are first described. Data are reported. Then two newly developed predictive models based on thermodynamic approach with the isofugacity criterion and artificial neural network method are presented. The results can provide better evaluation of refrigerants, especially with the aim of studying global warning effects.

  14. Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

    Science.gov (United States)

    Smith, G. B.

    1996-01-01

    The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

  15. Tutelage of man's terrestrial patrimony: Urgency for tenable development

    International Nuclear Information System (INIS)

    Urgency for prompt and coordinated action by industrialized countries is emphasized in this analysis of the earth's most pressing environmental problems - desertification, acid rain, deforestation, the greenhouse effect and ozone depletion. In the analysis of the chemical, physical, thermochemical and climatic processes (e.g., ozone reactions with chlorofluorocarbons, Antarctic atmospheric vortex circulation, volcanic eruptions, the earth's water and carbon cycles, cyclic global temperature variations, etc.) governing the formation and modification of the various environmentally destabilizing phenomena, and in the assessments of the severity and duration of the effects, the paper evidences global and socio-economic aspects relative to the probable causes and proposed solutions. The author states that whereas greater investment by industrialized countries in environmental protection and technology transfer programs is essential to save the earth's natural resources, overall positive results can be achieved only through a contemporaneous change in social values to favour the sharing of the earth's wealth among nations and future generations

  16. Influence of Zeotropic Mixtures' Temperature Gliding on the Performance of Heat Transfer in Condenser or Evaporator

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li; GAO Pan

    2005-01-01

    Many zeotropic refrigerant mixtures are proposed as alternatives to some chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). An advantage of zeotropic mixtures is the possibility of reduction in entropy generation by matching the temperature glidings of refrigerant and heat-transfer fluid in both condenser and evaporator. Zeotropic mixtures are compared with pure refrigerants to evaluate their exergetic losses. On the other hand, the special phenomena which result from temperature gliding are proved by experiments. A simple equation is obtained, to evaluate different zeotropic mixtures' exergetic losses. The maximum flow rate of heat-transfer fluids is found in order that refrigerants phase change can be completed. Lastly, some examples of zeotropic mixtures (R407C, R405A and R414B) are given, and their exergetic losses and maximum flow rate of heat-transfer fluids in condenser are forecasted.

  17. Emergence of healing in the Antarctic ozone layer.

    Science.gov (United States)

    Solomon, Susan; Ivy, Diane J; Kinnison, Doug; Mills, Michael J; Neely, Ryan R; Schmidt, Anja

    2016-07-15

    Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically driven increase in polar ozone (or "healing") is expected in response to this historic agreement. Observations and model calculations together indicate that healing of the Antarctic ozone layer has now begun to occur during the month of September. Fingerprints of September healing since 2000 include (i) increases in ozone column amounts, (ii) changes in the vertical profile of ozone concentration, and (iii) decreases in the areal extent of the ozone hole. Along with chemistry, dynamical and temperature changes have contributed to the healing but could represent feedbacks to chemistry. Volcanic eruptions have episodically interfered with healing, particularly during 2015, when a record October ozone hole occurred after the Calbuco eruption. PMID:27365314

  18. Distribution of Isotopic and Environmental Tracers in Groundwater, Northern Ada County, Southwestern Idaho

    Science.gov (United States)

    Adkins, Candice B.; Bartolino, James R.

    2010-01-01

    Residents of northern Ada County, Idaho, depend on groundwater for domestic and agricultural uses. The population of this area is growing rapidly and groundwater resources must be understood for future water-resource management. The U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, used a suite of isotopic and environmental tracers to gain a better understanding of groundwater ages, recharge sources, and flowpaths in northern Ada County. Thirteen wells were sampled between September and October 2009 for field parameters, major anions and cations, nutrients, oxygen and hydrogen isotopes, tritium, radiocarbon, chlorofluorocarbons, and dissolved gasses. Well depths ranged from 30 to 580 feet below land surface. Wells were grouped together based on their depth and geographic location into the following four categories: shallow aquifer, intermediate/deep aquifer, Willow Creek aquifer, and Dry Creek aquifer. Major cations and anions indicated calcium-bicarbonate and sodium-bicarbonate water types in the study area. Oxygen and hydrogen isotopes carried an oxygen-18 excess signature, possibly indicating recharge from evaporated sources or water-rock interactions in the subsurface. Chlorofluorocarbons detected modern (post-1940s) recharge in every well sampled; tritium data indicated modern water (post-1951) in seven, predominantly shallow wells. Nutrient concentrations tended to be greater in wells signaling recent recharge based on groundwater age dating, thus confirming the presence of recent recharge in these wells. Corrected radiocarbon results generated estimated residence times from modern to 5,100 years before present. Residence time tended to increase with depth, as confirmed by all three age-tracers. The disagreement among residence times indicates that samples were well-mixed and that the sampled aquifers contain a mixture of young and old recharge. Due to a lack of data, no conclusions about sources of recharge could be drawn

  19. Stratospheric ozone depletion.

    Science.gov (United States)

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  20. Hydrogeology of Two Areas of the Tug Hill Glacial-Drift Aquifer, Oswego County, New York

    Science.gov (United States)

    Miller, Todd S.; Bugliosi, Edward F.; Hetcher-Aguila, Kari K.; Eckhardt, David A.

    2007-01-01

    Two water-production systems, one for the Village of Pulaski and the other for the Villages of Sandy Creek and Lacona in Oswego County, New York, withdraw water from the Tug Hill glacial-drift aquifer, a regional sand and gravel aquifer along the western flank of the Tug Hill Plateau, and provide the sole source of water for these villages. As a result of concerns about contamination of the aquifer, two studies were conducted during 2001 to 2004, one for each water-production system, to refine the understanding of ground-water flow surrounding these water-production systems. Also, these studies were conducted to determine the cause of the discrepancy between ground-water ages estimated from previously constructed numerical ground-water-flow models for the Pulaski and Sandy Creek/Lacona well fields and the apparent ground-water ages determined using concentrations of tritium and chlorofluorocarbons. The Village of Pulaski withdrew 650,000 gallons per day in 2000 from four shallow, large-diameter, dug wells finished in glaciolacustrine deposits consisting of sand with some gravelly lenses 3 miles east of the village. Four 2-inch diameter test wells were installed upgradient from each production well, hydraulic heads were measured, and water samples collected and analyzed for physical properties, inorganic constituents, nutrients, bacteria, tritium, dissolved gases, and chlorofluorocarbons. Recharge to the Tug Hill glacial-drift aquifer is from precipitation directly over the aquifer and from upland sources in the eastern part of the recharge area, including (1) unchannelized runoff from till and bedrock hills east of the aquifer, (2) seepage to the aquifer from streams that drain the Tug Hill Plateau, (3) ground-water inflow from the till and bedrock on the adjoining Tug Hill Plateau. Water-quality data collected from four piezometers near the production wells in November 2003 indicated that the water is a calcium-bicarbonate type with iron concentrations that

  1. Efficacy and safety of eco-friendly inhalers: focus on combination ipratropium bromide and albuterol in chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Panos RJ

    2013-04-01

    Full Text Available Ralph J Panos1,2 1Pulmonary, Critical Care, and Sleep Medicine Division, Cincinnati Veterans Affairs Medical Center, 2Pulmonary, Critical Care, and Sleep Medicine Division, University of Cincinnati College of Medicine, Cincinnati, OH, USA Background: Chronic obstructive pulmonary disease (COPD is a major cause of morbidity and mortality and its treatment is critical to improve quality of life, reduce symptoms, and diminish the frequency of COPD exacerbations. Due to the harmful environmental effects of pressurized metered-dose inhalers (pMDIs containing chlorofluorocarbons (CFCs, newer systems for delivering respiratory medications have been developed. Methods: A search of the literature in the PubMed database was undertaken using the keywords “COPD,” “albuterol,” “ipratropium bromide,” and “Respimat® Soft Mist Inhaler™”; pertinent references within the identified citations were included. The environmental effect of CFC-pMDIs, the invention of the Respimat® Soft Mist Inhaler™ (SMI (Boehringer Ingelheim, Ingelheim, Germany, and its use to deliver the combination of albuterol and ipratropium bromide for the treatment of COPD were reviewed. Results: The adverse environmental effects of CFC-pMDIs stimulated the invention of novel delivery systems including the Respimat SMI. This review presents its development, internal mechanism, and use to deliver the combination of albuterol and ipratropium bromide. Conclusion: CFC-pMDIs contributed to the depletion of the ozone layer and the surge in disorders caused by harmful ultraviolet B radiation. The banning of CFCs spurred the development of novel delivery systems for respiratory medications. The Respimat SMI is an innovative device that produces a vapor of inhalable droplets with reduced velocity and prolonged aerosol duration that enhance deposition within the lower airway and is associated with improved patient satisfaction. Clinical trials have demonstrated that the Respimat SMI

  2. Small-scale Geothermal Power Plants Using Hot Spring Water

    Science.gov (United States)

    Tosha, T.; Osato, K.; Kiuchi, T.; Miida, H.; Okumura, T.; Nakashima, H.

    2013-12-01

    The installed capacity of the geothermal power plants has been summed up to be about 515MW in Japan. However, the electricity generated by the geothermal resources only contributes to 0.2% of the whole electricity supply. After the catastrophic earthquake and tsunami devastated the Pacific coast of north-eastern Japan on Friday, March 11, 2011, the Japanese government is encouraging the increase of the renewable energy supply including the geothermal. It needs, however, more than 10 years to construct the geothermal power plant with more than 10MW capacity since the commencement of the development. Adding the problem of the long lead time, high temperature fluid is mainly observed in the national parks and the high quality of the geothermal resources is limited. On the other hand hot springs are often found. The utilisation of the low temperature hot water becomes worthy of notice. The low temperature hot water is traditionally used for bathing and there are many hot springs in Japan. Some of the springs have enough temperature and enthalpy to turn the geothermal turbine but a new technology of the binary power generation makes the lower temp fluid to generate electricity. Large power generators with the binary technology are already installed in many geothermal fields in the world. In the recent days small-scale geothermal binary generators with several tens to hundreds kW capacity are developed, which are originally used by the waste heat energy in an iron factory and so on. The newly developed binary unit is compact suitable for the installation in a Japanese inn but there are the restrictions for the temperature of the hot water and the working fluid. The binary power unit using alternatives for chlorofluorocarbon as the working fluid is relatively free from the restriction. KOBELCO, a company of the Kobe Steel Group, designed and developed the binary power unit with an alternative for chlorofluorocarbon. The unit has a 70 MW class electric generator. Three

  3. Trend Analyses of Nitrate in Danish Groundwater

    Science.gov (United States)

    Hansen, B.; Thorling, L.; Dalgaard, T.; Erlandsen, M.

    2012-04-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark. Are the Danish groundwater monitoring strategy obtimal for detection of nitrate trends? Will the nitrate concentrations in Danish groundwater continue to decrease or are the Danish nitrate concentration levels now appropriate according to the Water Framework Directive?

  4. Response to Out of Balance: The risk of irreversible climate change

    International Nuclear Information System (INIS)

    The Standing Committee on Environment of the Canadian House of Commons tabled a report entitled Out of Balance, which was an investigation of issues related to the increasing concentrations of greenhouse gases in the atmosphere and possible responses to impending climatic change. The government's response to the recommendations made in that report are presented. The framework to the government's response is first introduced, which includes the National Action Strategy on Global Warming (NASGW) that provides a strategy for Canadian initiatives to reduce greenhouse gas emissions. The strategy is based on the fundamental principles of comprehensiveness, the importance of international agreements, and flexibility. The Standing Committee's recommendations focused on policies to limit Canadian emissions of carbon dioxide, one of the major greenhouse gases. Canadian policies to achieve this goal are being implemented in the Green Plan and the NASGW. Other recommendations and responses involve environmental education, greenhouse gas data collection, phasing out of chlorofluorocarbons, natural gas leakage, energy conservation and demand management, regulatory systems, fuel efficiency standards, forest management, greenhouse gas emissions from federal departments and agencies, and encouragement of environmentally acceptable technologies

  5. Global warming: Towards a strategy for Ontario

    International Nuclear Information System (INIS)

    A discussion paper is provided as background to a proposed public review of a strategy for Ontario's response to global warming. Global warming arises from the generation of greenhouse gases, which come from the use of fossil fuels, the use of chlorofluorocarbons, and deforestation. Energy policy is the backbone of achieving climate stability since the burning of fossil fuels releases most of the greenhouse gases, mainly carbon dioxide. Canada is, by international standards, a very energy-intensive country and is among the world's largest emitters of carbon dioxide on a per capita basis. Ontario is the largest energy-using province in Canada, and fossil fuels represent over 80% of provincial energy use. A proposed goal for Ontario is to provide leadership in stabilizing atmospheric concentrations of the greenhouse gases, while minimizing the social, economic, and environmental costs in Ontario of adapting to global warming. A proposed first step to address global warming is to achieve reductions in expected emissions of the greenhouse gases, especially carbon dioxide, so that levels by the year 2000 are lower than in 1989. Current policies and regulations helping to reduce the greenhouse effect include some of the current controls on automotive emissions and the adoption by the provincial electric utility of targets to reduce electricity demand. New initiatives include establishment of minimum energy efficiency standards and reduction of peak-day electricity use. Action steps for future consideration are detailed in the categories of greenhouse gas emissions reductions, carbon dioxide absorption, and research and analysis into global warming

  6. Comparison of halocarbon measurements in an atmospheric dry whole air sample

    Directory of Open Access Journals (Sweden)

    George C. Rhoderick

    2015-11-01

    Full Text Available Abstract The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance. A common source of standards/scales and/or well-documented agreement of different scales used to calibrate the measurement instrumentation are key to understanding many sets of data reported by researchers. This report describes the results of a comparison study among National Metrology Institutes and atmospheric research laboratories for the chlorofluorocarbons (CFCs dichlorodifluoromethane (CFC-12, trichlorofluoromethane (CFC-11, and 1,1,2-trichlorotrifluoroethane (CFC-113; the hydrochlorofluorocarbons (HCFCs chlorodifluoromethane (HCFC-22 and 1-chloro-1,1-difluoroethane (HCFC-142b; and the hydrofluorocarbon (HFC 1,1,1,2-tetrafluoroethane (HFC-134a, all in a dried whole air sample. The objective of this study is to compare calibration standards/scales and the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. The results of this study show agreement among four independent calibration scales to better than 2.5% in almost all cases, with many of the reported agreements being better than 1.0%.

  7. F. Sherwood “Sherry” Rowland (1927-2012)

    Science.gov (United States)

    Blake, Donald R.; Simpson, Isobel J.

    2012-10-01

    Frank Sherwood Rowland, known to his friends and colleagues as Sherry, died at his home in Corona del Mar, Calif., on 10 March 2012. He was 84. A Nobel Prize-winning atmospheric chemist, Sherry codiscovered the role of chlorofluorocarbons (CFCs) in stratospheric ozone depletion, researched the accumulation of greenhouse gases on a planetary scale, and tirelessly communicated the global consequences of human activity to policy makers and the public. Sherry had a calm, gentle demeanor and was as respected for his integrity and humility as for his groundbreaking scientific achievements. Sherry was a long-time member and Fellow (1980) of AGU and received the AGU Roger Revelle Medal in 1994 for his substantial contributions to the awareness of global change. The following year, he shared the Nobel Prize in Chemistry with Mario Molina and Paul Crutzen for their pioneering contributions to atmospheric chemistry, particularly the formation and decomposition of stratospheric ozone. In its citation, the Nobel Committee commended them for contributing to "our salvation from a global environmental problem that could have catastrophic consequences."

  8. Options to accelerate ozone recovery: ozone and climate benefits

    Directory of Open Access Journals (Sweden)

    J. S. Daniel

    2010-08-01

    Full Text Available Hypothetical reductions in future emissions of ozone-depleting substances (ODSs and N2O are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC, globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact on ozone depletion that regulations already in force have had. If all anthropogenic ODS and N2O emissions were halted beginning in 2011, ozone is calculated to be higher by about 1–2% during the period 2030–2100 compared to a case of no additional restrictions. Direct radiative forcing by 2100 would be about 0.23 W/m2 lower from the elimination of anthropogenic N2O emissions and about 0.005 W/m2 lower from the destruction of the chlorofluorocarbon (CFC bank. Due to the potential impact of N2O on future ozone levels, we provide an approach to incorporate it into the EESC formulation, which is used extensively in ozone depletion analyses. The ability of EESC to describe total ozone changes arising from additional ODS and N2O controls is also quantified.

  9. Options to accelerate ozone recovery:ozone and climate benefits

    Directory of Open Access Journals (Sweden)

    J. S. Daniel

    2010-04-01

    Full Text Available Hypothetical reductions in future emissions of ozone-depleting substances (ODSs, including N2O, are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC, globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact that regulations already in force have had. If all anthropogenic ODS emissions were halted beginning in 2011, ozone is calculated to be higher by about 1–2{%} during the period 2030–2100 compared to a case of no additional ODS restrictions. Radiative forcing by 2100 would be about 0.23 W/m2 lower due to the elimination of N2O emissions and about 0.005 W/m2 lower due to destruction of the chlorofluorocarbon (CFC bank. The ability of EESC to be a suitable metric for total ozone is also quantified. Responding to the recent suggestion that N2O should be considered an ODS, we provide an approach to incorporate N2O into the EESC formulation.

  10. Membrane vapor recovery systems. Phase 2, Progress report, 1 October 1991--29 September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.; Davidson, J.E.; Helm, V.D.; Hofmann, T.R.; Kamaruddin, H.D.; Kaschemekat, J.; Olsen, R.P.; Rose, M.E.; Wijmans, J.G.

    1992-12-31

    This report describes Phase II of a project to design, construct, and demonstrate in the membrane separation system able to recover volatile organic compounds field a condensation/membrane separation system able to recover volatile organic compounds from effluent air streams. In the first phase of the program, a number of the high-pressure membrane modules to be installed in the system were constructed and evaluated, and the Field Demonstration Unit was designed. In the second phase, the Field Demonstration System was constructed and operated at MTR`s laboratories with perchloroethylene, trichlorotrifluoroethane, and hexane, representative of chlorinated hydrocarbons, chlorofluorocarbons and fuel hydrocarbons, respectively. VOC removal from the feed stram was between 80% and 99.8%. Removal increased with increasing VOC content and with decreasing VOC volatility. A Module Field Evaluation Unit was also constructed for testing at the El Dorado plant of Great Lakes Chemical Corporation. The system, consisting of one membrane module housing containing one module insert, is installed on the pressurized vent from a condenser.

  11. On detecting a trend in the residual circulation from observations of column HCl

    Science.gov (United States)

    Olsen, M. A.; Douglass, A. R.; Stolarski, R. S.; Schoeberl, M. R.

    2006-01-01

    The troposphere is the part of the atmosphere where people live. The troposphere goes up to about 12 km above the earth over places at middle latitudes like Washington, D.C. The next layer of air up in the atmosphere is called the stratosphere. The tropopause separates the troposphere and stratosphere. Most of the ozone in the atmosphere is in the stratosphere where it protects people from the harmful rays in sunlight. Near the earth s surface, ozone is a pollutant. In general, air travels from the troposphere to the stratosphere through upward motion in the tropics. Most of the air comes back down to the troposphere at middle latitudes. The so-called "stratospheric residual circulation" moves the air in the stratosphere from the tropics to the middle latitudes. In this way, the amount of air that moves out of the stratosphere into the troposphere at middle latitudes depends on the strength of the residual circulation. This overturning of the atmosphere is important as it brings chemicals produced by the activities of people into the stratosphere. Most notable are chlorofluorocarbons (CFCs) that destroy stratospheric ozone. The transport of air out of the stratosphere removes ozone-destroying chemicals, but also brings ozone into the troposphere.

  12. A decade of discontinuity.

    Science.gov (United States)

    Brown, L R

    1993-01-01

    Usual trends in the world have changed direction in the 1990s. We do not yet fully know the consequences of these altered trends. As population continues to grow, basic agricultural and industrial production falls (e.g., 1%/year decline in grain production and 0.6%/year decline in oil production). Moreover, world economic growth has fallen .8% annually in the early 1990s. It is feared that these shifts are not short term as were the instabilities generated during the 1973 increase in oil prices. The shifts in the 1990s are not limited to several national political leaders (e.g., OPEC), but are a result of the collision between swelling human numbers and their needs and the limitations of the earth's natural systems on the other. These limitations include the capacity of seas to produce seafood, of grasslands to yield mutton and beef, of the hydrological cycle to generate fresh water, of crops to use fertilizer, of the atmosphere to absorb carbon dioxide and chlorofluorocarbons, and of people to inhale polluted air, and of forests to resist acid rain. These constraints are forcing the realization that each nation must reduce consumption of the earth's natural resources and implement a population policy. The challenge is for social institutions to quickly check and stabilize population growth without infringing in human rights. PMID:12286579

  13. Health effects associated with energy conservation measures in commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Stenner, R.D.; Baechler, M.C.

    1990-09-01

    Indoor air quality can be impacted by hundreds of different chemicals. More than 900 different organic compounds alone have been identified in indoor air. Health effects that could arise from exposure to individual pollutants or mixtures of pollutants cover the full range of acute and chronic effects, including largely reversible responses, such as rashes and irritations, to the irreversible toxic and carcinogenic effects. These indoor contaminants are emitted from a large variety of materials and substances that are widespread components of everyday life. Pacific Northwest Laboratory conducted a search of the peer-reviewed literature on health effects associated with indoor air contaminants for the Bonneville Power Administration to aid the agency in the preparation of environmental documents. Results are reported in two volumes. Volume 1 summarizes the results of the search of the peer-reviewed literature on health effects associated with a selected list of indoor air contaminants. In addition, the report discusses potential health effects of polychlorinated biphenyls and chlorofluorocarbons. All references to the literature reviewed are found in this document Volume 2. Volume 2 provides detailed information from the literature reviewed, summarizes potential health effects, reports health hazard ratings, and discusses quantitative estimates of carcinogenic risk in humans and animals. Contaminants discussed in this report are those that; have been measured in the indoor air of a public building; have been measured (significant concentrations) in test situations simulating indoor air quality (as presented in the referenced literature); and have a significant hazard rating. 38 refs., 7 figs., 23 tabs.

  14. Possible atmospheric lifetimes and chemical reaction mechanisms for selected HCFCs, HFCs, CH3CCl3, and their degradation products against dissolution and/or degradation in seawater and cloudwater

    Science.gov (United States)

    Wine, P. H.; Chameides, W. L.

    1990-01-01

    For a wide variety of atmospheric species including CO2, HNO3, and SO2, dissolution in seawater or cloudwater followed by hydrolysis or chemical reaction represents a primary pathway for removal from the atmosphere. In order to determine if this mechanism can also remove significant amounts of atmospheric chlorofluorocarbons (HCFC's), fluorocarbons (HFC's), and their degradation products, an investigation was undertaken as part of the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). In this investigation, the rates at which CHCl2CF3 (HCFC-123), CCl2FCH3 (HCFC-141b), CClF2CH3 (HCFC-142b), CHClF2 (HCFC-22), CHClFCF3 (HCFC-124) CH2FCF3 (HFC-134a) CHF2CH3 (HFC-152a), CHF2CF3 (HFC-125), and CH3CCl3 can be dissolved in the oceans and in cloudwater were estimated from the species' thermodynamic and chemical properties using simple mathematical formulations to simulate the transfer of gases from the atmosphere to the ocean or cloudwater. The ability of cloudwater and rainwater to remove gas phase degradation products of these compounds was also considered as was the aqueous phase chemistry of the degradation products. The results of this investigation are described.

  15. Health effects associated with energy conservation measures in commercial buildings

    International Nuclear Information System (INIS)

    Indoor air quality can be impacted by hundreds of different chemicals. More than 900 different organic compounds alone have been identified in indoor air. Health effects that could arise from exposure to individual pollutants or mixtures of pollutants cover the full range of acute and chronic effects, including largely reversible responses, such as rashes and irritations, to the irreversible toxic and carcinogenic effects. These indoor contaminants are emitted from a large variety of materials and substances that are widespread components of everyday life. Pacific Northwest Laboratory conducted a search of the peer-reviewed literature on health effects associated with indoor air contaminants for the Bonneville Power Administration to aid the agency in the preparation of environmental documents. Results are reported in two volumes. Volume 1 summarizes the results of the search of the peer-reviewed literature on health effects associated with a selected list of indoor air contaminants. In addition, the report discusses potential health effects of polychlorinated biphenyls and chlorofluorocarbons. All references to the literature reviewed are found in this document Volume 2. Volume 2 provides detailed information from the literature reviewed, summarizes potential health effects, reports health hazard ratings, and discusses quantitative estimates of carcinogenic risk in humans and animals. Contaminants discussed in this report are those that; have been measured in the indoor air of a public building; have been measured (significant concentrations) in test situations simulating indoor air quality (as presented in the referenced literature); and have a significant hazard rating. 38 refs., 7 figs., 23 tabs

  16. The Importance of the Montreal Protocol in Protecting the Earth's Hydroclimate

    Science.gov (United States)

    Seager, R.; Wu, Y.; Polvani, L. M.

    2012-12-01

    The 1987 Montreal Protocol regulating emissions of ozone depleting chlorofluorocarbons (CFCs) was motivated primarily by the harm to human health and ecosystems arising from increased exposure to ultraviolet-B (UV-B) radiation associated with depletion from the ozone layer. It is now known that the Montreal Protocol has reduced global warming since CFCs are greenhouse gases (GHGs). In this paper we show that the Montreal Protocol also significantly protects the Earth's hydroclimate, even though this was also not a motivating factor in the decision-making that led to the Protocol. General Circulation Model (GCM) results show that in the coming decade (2020-29), under the 'World Avoided' scenario of no regulations on CFC emissions, the subtropical dry zones would in general get drier, and the middle and high latitude regions wetter. This change is similar, in both pattern and magnitude, to that in the coming decade caused by projected increases in carbon dioxide concentrations. This implies that because of the Montreal Protocol, and the ozone depletion and global warming associated with CFCs thus avoided, the hydrological cycle changes in the coming decade will be significantly less than what they otherwise would have been.

  17. Packed bed reactor treatment of liquid hazardous and mixed wastes

    International Nuclear Information System (INIS)

    We are developing thermal-based packed bed reactor (PBR) technology as an alternative to incineration for treatment of hazardous organic liquid wastes. The waste streams targeted by this technology are machining fluids contaminated with chlorocarbons and/or chlorofluorocarbons and low levels of plutonium or tritium The PBR offers several distinct advantages including simplistic design, rugged construction, ambient pressure processing, economical operations, as well as ease of scalability and maintainability. In this paper, we provide a description of the apparatus as well as test results using prepared mixtures of machining oils/emulsions with trichloroethylene (TCE), carbon tetrachloride (CCl4), trichloroethane (TCA), and Freon TF. The current treatment system is configured as a two stage device with the PBR (1st stage) coupled to a silent discharge plasma (SDP) cell. The SDP serves as a second stage for further treatment of the gaseous effluent from the PBR. One of the primary advantages of this two stage system is that its suitability for closed loop operation where radioactive components are well contained and even CO2 is not released to the environment

  18. A new method used to evaluate organic working fluids

    International Nuclear Information System (INIS)

    In this paper, we propose a method named “Weight Classification-Hasse Dominance” to evaluate organic working fluids. This new method combines the advantages of both the method of weight determination and the Hasse Diagram Technique (HDT). It can be used to evaluate the thermodynamic performance, environmental protection indicator, and safety requirement of organic working fluid simultaneously. This evaluation method can offer good reference for working fluid selection. Using this method, the organic working fluids which have been phased out and will be phased out by the Montreal Protocol including CFCs (chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), and HFCs (hydrofluorocarbons) were evaluated. Moreover, HCs (hydrocarbons) can be considered as a completely different kind of organic working fluid from CFCs, HCFCs, and HFCs according to the comparison based on this new evaluation method. - Highlights: • We propose a new method used to evaluate organic working fluids. • This evaluation method can offer good reference for working fluid selection. • CFC, HCFC, and HFC working fluids were evaluated using this evaluation method. • HC can be considered as a totally different working fluid from CFC, HCFC, and HFC

  19. Nanocarriers as pulmonary drug delivery systems to treat and to diagnose respiratory and non respiratory diseases

    Directory of Open Access Journals (Sweden)

    Malgorzata Smola

    2008-03-01

    Full Text Available Malgorzata Smola1,2, Thierry Vandamme1, Adam Sokolowski21Université Louis Pasteur, Faculté de Pharmacie, Département de Chimie Bioorganique, Illkirch Graffenstaden, France; 2Wroclaw University of Technology, Faculty of Chemical Engineering, Wroclaw, PolandAbstract: The purpose of this review is to discuss the impact of nanocarriers administered by pulmonary route to treat and to diagnose respiratory and non respiratory diseases. Indeed, during the past 10 years, the removal of chlorofluorocarbon propellants from industrial and household products intended for the pulmonary route has lead to the developments of new alternative products. Amongst these ones, on one hand, a lot of attention has been focused to improve the bioavailability of marketed drugs intended for respiratory diseases and to develop new concepts for pulmonary administration of drugs and, on the other hand, to use the pulmonary route to administer drugs for systemic diseases. This has led to some marketed products through the last decade. Although the introduction of nanotechnology permitted to step over numerous problems and to improve the bioavailability of drugs, there are, however, unresolved delivery problems to be still addressed. These scientific and industrial innovations and challenges are discussed along this review together with an analysis of the current situation concerning the industrial developments.Keywords: nanotechnology, nanocarriers, nanoparticle, liposome, lung, pulmonary drug delivery, drug targeting, respiratory disease, microemulsion, bioavailability, micelle

  20. Residence times and age distributions of spring waters at the Semmering catchment area, Eastern Austria, as inferred from tritium, CFCs and stable isotopes.

    Science.gov (United States)

    Han, Liangfeng; Hacker, Peter; Gröning, Manfred

    2007-03-01

    The groundwater system in the mountainous area of Semmering, Austria, was studied by environmental tracers in several karst springs. The tracers used included stable isotopes ((18)O, (2)H), tritium ((3)H) and chlorofluorocarbons (CFCs). The tracers provided valuable information in regard to (1) the mean altitude of the spring catchment areas; (2) the residence time and age distribution of the spring waters; and (3) the interconnection of the springs to a sinkhole. The combination of the stable isotopic data and the topography/geology provided the estimates of the mean altitudes of the catchment areas. Based on the stable isotopic data the recharge temperature of the spring waters was estimated. The smoothing of precipitation's isotopic signal in spring discharge provided information on the minimum transit time of the spring waters. Due to short observation time, (3)H data alone cannot be used for describing the mean residence time of the karst waters. CFCs, though useful in recognizing the co-existence of young (post-1993) water with old (CFC-free) water, could not be used to resolve age distribution models. It is shown in this article, however, that the combined use of tritium and CFCs can provide a better assessment of models to account for different groundwater age distributions. In Appendix A, a simplified method for collecting groundwater samples for the analysis of CFCs is described. The method provides a real facilitation for fieldwork. Test data are given for this sampling method in regard to potential contamination by atmospheric CFCs.

  1. Fiscal 1999 survey report. Part 2. Research study on restraint of carbon dioxide generation by green chemistry; 1999 nendo green chemistry ni yoru CO{sub 2} hassei yokusei ni kakawaru chosa kenkyu. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    In connection with green chemistry, a concept of bringing paradigm shift to chemical technologies as something that makes reduction in environmental load compatible with economic activities; surveys were made this year on the developments of fine chemicals from renewable resources such as cellulose among the cases of developing chemical substances/products to be called 'green chemicals' reducing environmental load; developments of surfactants produced by certain microorganism, plastic additives with reduced pollutant loads, particularly fire retardants and environmentally benign reactant solvents; concept of green chemistry in the development of chlorofluorocarbon-alternatives; and up-to-date technological level concerning a design method of chemical materials and an estimation method for chemical safety using quantum chemistry calculation. In regard to the chemical materials and products intrinsically containing a certain level of risk, R and D should be reinforced and accelerated in the future on the alternative materials/products reducing their toxicity. In this case, along with the importance of discussing compatibility of technological possibility with economical adaptability, sociological study seems to be necessary in incorporating environmental load reduction into economic evaluation. (NEDO)

  2. Application of environmental tracers to mixing, evolution, and nitrate contamination of ground water in Jeju Island, Korea

    Science.gov (United States)

    Koh, Dong-Chan; Niel Plummer, L.; Kip Solomon, D.; Busenberg, Eurybiades; Kim, Yong-Je; Chang, Ho-Wan

    2006-07-01

    SummaryTritium/helium-3 ( 3H/ 3He) and chlorofluorocarbons (CFCs) were investigated as environmental tracers in ground water from Jeju Island (Republic of Korea), a basaltic volcanic island. Ground-water mixing was evaluated by comparing 3H and CFC-12 concentrations with lumped-parameter dispersion models, which distinguished old water recharged before the 1950s with negligible 3H and CFC-12 from younger water. Low 3H levels in a considerable number of samples cannot be explained by the mixing models, and were interpreted as binary mixing of old and younger water; a process also identified in alkalinity and pH of ground water. The ground-water CFC-12 age is much older in water from wells completed in confined zones of the hydro-volcanic Seogwipo Formation in coastal areas than in water from the basaltic aquifer. Major cation concentrations are much higher in young water with high nitrate than those in uncontaminated old water. Chemical evolution of ground water resulting from silicate weathering in basaltic rocks reaches the zeolite-smectite phase boundary. The calcite saturation state of ground water increases with the CFC-12 apparent (piston flow) age. In agricultural areas, the temporal trend of nitrate concentration in ground water is consistent with the known history of chemical fertilizer use on the island, but increase of nitrate concentration in ground water is more abrupt after the late 1970s compared with the exponential growth of nitrogen inputs.

  3. Response to 'Perception of risk and the future of nuclear power'

    International Nuclear Information System (INIS)

    In our own domestic politics in the United States, examples of renunciation of a civilian technology that I can think of easily are the Supersonic Transport, where we made a social decision not to subsidize production of the 2000 mile per hour Boeing embodiment, and the related decision to begin restricting the use of chlorofluorocarbons (CFCs). We began doing the latter in the 1970s, more as a fallout of the Supersonic Transport debate than the self-standing concern it has become. We now have global arrangements to cut back on CFCs, and it would appear that the ones that we have had are going to be tightened. Those are very unusual in the history of technology. it was not a vote of the people that caused inter-urban trams to go out of service. You can look at the history of Los Angeles and say there were some local votes of bodies that were manipulated to hasten the decline of them, but on the whole, technologies are not voted up or down by the people. This is not a plebiscitary thing. In polling, there is an implication that you are taking a sounding of the people and are acting as a result of that sounding. Perception is that everyone is pushing their button, and then you do something

  4. Substitutes for HCFCs: Experience in refrigeration engineering and air-conditioning in the USA; Ersatzstoffe fuer H-FCKW: US-amerikanische Erfahrungen in Kaelte- und Klimaanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-08-01

    Nowhere is the phasing out of H-chlorofluorocarbons more demanding than in the USA, where they are are used in most central residential air-conditioning and heat pump systems and in many refrigeration-technical applications. Under the Montreal protocol, the production of HCFCs may be continued until the year 2020 (and, to a very limited extent, until 2030). Yet, the available amounts of R 22 will more and more decrease over time. Therefore, provision must be made to ensure that alternative refrigerants are available which can be used in both existing plant and new ones. The paper describes the course and current state of the search for HCFCs in the USA. (orig.) [Deutsch] Der Ausstieg aus den H-FCKW ist nirgendwo anspruchsvoller als in den USA, wo diese in den meisten zentralen Wohnraumklimaanlagen und Waermepumpensystemen und in vielen kaeltetechnischen Anwendungen eingesetzt werden. Das Montreal Protokoll erlaubt die Produktion von H-FCKW bis zum Jahr 2020 (und in sehr begrenzten Mengen bis 2030). Dennoch werden die verfuegbaren Mengen von R 22 im Laufe der Zeit immer geringer werden. Daher muss mit dem Ausstieg aus dem H-FCKW dafuer gesorgt werden, dass alternative Kaeltemittel als Retrofit fuer bestehende Anlagen zur Verfuegung stehen und ebenso in Neuanlagen eingesetzt werden koennen. Dieser Artikel beschreibt den bisherigen Verlauf und den gegenwaertigen Stand der Untersuchung von Alternativen fuer H-FCKW in den USA. (orig.)

  5. Characterization and aerobic biodegradation of selected monoterpenes

    Energy Technology Data Exchange (ETDEWEB)

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  6. Carbon dioxide, hydrographic, and chemical data obtained in the South Pacific Ocean (WOCE Sections P16A/P17A, P17E/P19S, and P19C, R/V Knorr, October 1992--April 1993)

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, S.; Goddard, J.G.; Chipman, D.W.; Takahashi, Taro; Sutherland, S.C. [Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory; Reid, J.L.; Swift, J.H.; Talley, L.D. [Univ. of California, San Diego, La Jolla, CA (United States). Scripps Institution of Oceanography

    1998-06-01

    This data documentation discusses the procedures and methods used to measure total carbon dioxide concentration (TCO{sub 2}) and partial pressure of CO{sub 2} (pCO{sub 2}) in discrete water samples collected during three expeditions of the Research Vessel (R/V) Knorr in the South Pacific Ocean. Conducted as part of the World Ocean Circulation Experiment (WOCE), the first cruise (WOCE Section P16A/P17A) began in Papeete, Tahiti, French Polynesia, on October 6, 1992, and returned to Papeete on November 25, 1992. The second cruise (WOCE Section P17E/P19S) began in Papeete on December 4, 1992, and finished in Punta Arenas, Chile, on January 22, 1993. The third expedition (WOCE Section P19C) started in Punta Arenas, on February 22 and finished in Panama City, Panama, on April 13, 1993. During the three expeditions, 422 hydrographic stations were occupied. Hydrographic and chemical measurements made along WOCE Sections P16A/P17A, P17E/P19S, and P19C included pressure, temperature, salinity, and oxygen [measured by conductivity, temperature, and depth (CTD) sensor], as well as discrete measurements of salinity, oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO{sub 2}, and pCO{sub 2} measured at 4 and 20 C. In addition, potential temperatures were calculated from the measured variables.

  7. Substitutes for potent green house gases. HFCs, PFCs and SF{sub 6}. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, P.H. [Dansk Teknologisk Institut (Denmark)

    1997-12-31

    CFCs (halogenated chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons), PFCs (fluorocarbons) and SF{sub 6} (sulphur hexafluoride) are all artificial substances which were not to be found in nature until recently. In 1995 the Danish consumption of HFC substances was approximately 740 tonnes, where the corresponding amount of SF{sub 6} was about 17 tonnes. If the entire amount of these substances was released to to the atmosphere, the resulting impact would correspond to an increased emission of greenhouse gases, corresponding to approximately 1.5 million tonnes of CO{sub 2}. HFC substances would account for 73%, SF{sub 6} with 25% and PFC for 1%. This corresponds to approximately 2.6% of the Danish CO{sub 2} emission (nearly 60 million tonnes per year). This corresponds to about half of the aimed 6% reduction of CO{sub 2} emission attained by introduction of mandatory green taxes on CO{sub 2}. According to experience from the CFC programme it is possible to recover some CFC and send it to controlled destruction. From 1993 to 1996 the refrigeration industry, for instance, has returned a total amount of 163 tonnes of CFC refrigerant through the KMO organization (Koelebranchens Miljoe Ordning). Most of this has been destroyed and a small amount has been purified and recycled afterwards. Similarly, it is likely to believe that some HFC refrigerant will be returned through the KMO organization. (au) 11 refs., also published in Danish

  8. Environmental tracers as indicators of karst conduits in groundwater in South Dakota, USA

    Science.gov (United States)

    Long, A.J.; Sawyer, J.F.; Putnam, L.D.

    2008-01-01

    Environmental tracers sampled from the carbonate Madison aquifer on the eastern flank of the Black Hills, South Dakota, USA indicated the approximate locations of four major karst conduits. Contamination issues are a major concern because these conduits are characterized by direct connections to sinking streams, high groundwater velocities, and proximity to public water supplies. Objectives of the study were to estimate approximate conduit locations and assess possible anthropogenic influences associated with conduits. Anomalies of young groundwater based on chlorofluorocarbons (CFCs), tritium, and electrical conductivity (EC) indicated fast moving, focused flow and thus the likely presence of conduits. ??18O was useful for determining sources of recharge for each conduit, and nitrate was a useful tracer for assessing flow paths for anthropogenic influences. Two of the four conduits terminate at or near a large spring complex. CFC apparent ages ranged from 15 years near conduits to >50 years in other areas. Nitrate-N concentrations >0.4 mg/L in groundwater were associated with each of the four conduits compared with concentrations ranging from <0.1 to 0.4 mg/L in other areas. These higher nitrate-N concentrations probably do not result from sinking streams but rather from other areas of infiltration. ?? Springer-Verlag 2007.

  9. Age-distribution estimation for karst groundwater: Issues of parameterization and complexity in inverse modeling by convolution

    Science.gov (United States)

    Long, A.J.; Putnam, L.D.

    2009-01-01

    Convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon (CFC) and tritium (3H) data are available. We show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined. As an example, the model was applied to water from a pumped well open to the Madison aquifer in central USA with input functions of CFC-11, CFC-12, CFC-113, and 3H, and was calibrated to several samples collected during a 16-year period. A bimodal age distribution was modeled to represent quick and slow flow less than 50 years old. The effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow. Quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0-2 and 26-41 years, respectively. The fraction of long-term flow (>50 years) was estimated but was not dateable. The different tracers had different degrees of influence on parameter estimation and uncertainty assessments, where 3H was the most critical, and CFC-113 was least influential.

  10. Coping with global environmental change -- role of science and democracy.

    Science.gov (United States)

    Menon, M G

    The world's population increased form about 3 billion in 1960 to 4 billion in 1974, to 5 billion in 1987, and it is projected to grow to 6 billion by 1991 and to 8 billion by 1992. Finite, nonrenewable resources have to satisfy the increased need for sustenance of this population excess in a sustainable economic development mold. Human activity has upset natural processes with negative environmental effects: Minamata disease in Japan caused by heavy metal pollution, global deforestation, and acid rain. The 1972 Conference on Human Environment in Stockholm dealt with industrial pollution. The UN Environment Programme (UNEP) was established subsequently. The theory of global warming caused by emissions of carbon dioxide, methane, nitrogen oxides, and halogens as predicted by a Swedish scientist decades ago is accumulating a body of evidence. The International Geosphere Biosphere Programme (IGBP) of the International Council of Scientific Unions attempt to explore the Earth's physical, chemical, and biological processes to predict global environmental changes. Success mandates data availability. Paleoclimatic evidence indicates previous cataclysms caused by climate change, thus agriculture could be affected massively by global warming. Improved scientific analysis of greenhouse gas emissions and crop simulation models for major agricultural areas are needed. The North-South dialogue in UN forums has been acrimonious without much success, although international cooperation has been fruitful with the adoption of the Montreal Protocol on phasing out ozone-depleting chlorofluorocarbons. Such cooperation is needed on energy consumption and sources. PMID:12285904

  11. COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

    Science.gov (United States)

    Westra, Douglas G.

    1993-01-01

    With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

  12. UV-B Radiation Contributes to Amphibian Population Declines

    Science.gov (United States)

    Blaustein, Andrew

    2007-05-01

    UV-B (280-315 nm) radiation is the most significant biologically damaging radiation at the terrestrial surface. At the organismal level, UV-B radiation can slow growth rates, cause immune dysfunction and result in sublethal damage. UV-B radiation can lead to mutations and cell death. Over evolutionary time, UV radiation has been an important stressor on living organisms. Natural events, including impacts from comets and asteroids, volcanic activity, supernova explosions and solar flares, can cause large-scale ozone depletion with accompanying increases in UV radiation. However, these natural events are transient. Moreover, the amount of ozone damage due to natural events depends upon a number of variables, including the magnitude of the event. This is different from modern-day human-induced production of chlorofluorocarbons (CFCs) and other chemicals that deplete stratospheric ozone continuously, resulting in long-term increases in UV-B radiation at the surface of the earth. We will briefly review the effects of UV-B exposure in one group of aquatic organisms_amphibians. UV-B has been implicated as a possible factor contributing to global declines and range reductions in amphibian populations.

  13. Neurotoxicity of 1-bromopropane: Evidence from animal experiments and human studies

    Directory of Open Access Journals (Sweden)

    Gaku Ichihara

    2012-04-01

    Full Text Available 1-Bromopropane was introduced as an alternative to ozone layer-depleting solvents such as chlorofluorocarbons and 1,1,1-trichloroethane. However, a dozen human cases have been reported with symptoms and signs of toxicity to 1-bromopropane including numbness, diminished vibration sense in the lower extremities as well as ataxic gait. An epidemiological study also demonstrated dose-dependent prolongation of distal latency and decrease in vibration sense in the lower extremities. The initial animal experiments helped to identify and analyze the initial human case of 1-bromopropane toxicity. However, animal data that can explain the central nervous system disorders in humans are limited. Nonetheless, animal data should be carefully interpreted especially in a high-order function of the central nervous system or neurological signs such as ataxia that is influenced by fundamental anatomical/physiological differences between humans and animals. Enzymatic activity in the liver may explain partly the difference in the susceptibility between humans and animals, but further studies are needed to clarify the biological factors that can explain the difference and commonality among the species.

  14. Chemical and Isotopic Composition and Gas Concentrations of Ground Water and Surface Water from Selected Sites At and Near the Idaho National Engineering and Environmental Laboratory, Idaho, 1994-97

    Energy Technology Data Exchange (ETDEWEB)

    E. Busenberg; L. N. Plummer; M. W. Doughten; P. K. Widman; R. C. Bartholomay (USGS)

    2000-05-30

    >From May 1994 through May 1997, the US Geological Survey, in cooperation with the US Department of Energy, collected water samples from 86 wells completed in the Snake River Plain aquifer at and near the Idaho National Engineering and Environmental Laboratory. The samples were analyzed for a variety of chemical constituents including all major elements and 22 trace elements. Concentrations of scandium, yttrium, and the lanthanide series were measured in samples from 11 wells and 1 hot spring. The data will be used to determine the fraction of young water in the ground water. The fraction of young water must be known to calculate the ages of ground water using chlorofluorocarbons. The concentrations of the isotopes deuterium, oxygen-18, carbon-13, carbon-14, and tritium were measured in many ground water, surface-water and spring samples. The isotopic composition will provide clues to the origin and sources of water in the Snake River Plain aquifer. Concentrations ! of helium-3 , helium-4, total helium, and neon were measured in most groundwater samples, and the results will be used to determine the recharge temperature, and to date the ground waters.

  15. Linkages between ozone depleting substances, tropospheric oxidation and aerosols

    Directory of Open Access Journals (Sweden)

    A. Voulgarakis

    2012-09-01

    Full Text Available Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric Ozone Depleting Substances (ODS on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O emissions. We also find that without the regulation of chlorofluorocarbons (CFCs through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The historical radiative forcing of CFCs through their indirect effects on methane (−22.6 mW m−2 and sulfate aerosols (−3.0 mW m−2 discussed here is non-negligible when compared to known historical CFC forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  16. The influence of negative climate changes on physical development of urban and rural areas in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Rahman NURKOVIĆ

    2014-11-01

    Full Text Available The influence of negative climate changes on physical development of urban and rural areas of Bosnia and Herzegovina has been analysed in the paper. So, economy and society in urban and rural areas of Bosnia and Herzegovina are susceptible to environmental consequences of climate changes. In practice, this means that poorer countries in development of economic activities will suffer most due to climate changes, while some developed countries can be in a position to use new commercial possibilities. Presently, there is a significant scientific consensus that human activity affected the increase of atmospheric concentration of greenhouse gases, respectively the carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbon, as a result of global changes of climate that will probably change dramatically during the next centuries in Bosnia and Herzegovina. More and more intensive industrialisation and urbanisation, as well as tourism, a growing phenomenon of the 21st century, have numerous negative direct, indirect and multiplicative effects on flora and fauna habitats of Bosnia and Herzegovina. For all mentioned above, this paper tries to indicate to a need for more significant investing into tourism development, which is presently at a very low level of development in Bosnia and Herzegovina. In the past ten years a dynamical development of tertiary activities in urban and rural areas has been distinguished; among which shopping centres take a significant position. 

  17. Production of Nitrogen Oxides by Laboratory Simulated Transient Luminous Events

    Science.gov (United States)

    Peterson, H.; Bailey, M.; Hallett, J.; Beasley, W.

    2007-12-01

    Restoration of the polar stratospheric ozone layer has occurred at rates below those originally expected following reductions in chlorofluorocarbon (CFC) usage. Additional reactions affecting ozone depletion now must also be considered. This research examines nitrogen oxides (NOx) produced in the middle atmosphere by transient luminous events (TLEs), with NOx production in this layer contributing to the loss of stratospheric ozone. In particular, NOx produced by sprites in the mesosphere would be transported to the polar stratosphere via the global meridional circulation and downward diffusion. A pressure-controlled vacuum chamber was used to simulate middle atmosphere pressures, while a power supply and in-chamber electrodes were used to simulate TLEs in the pressure controlled environment. Chemiluminescence NOx analyzers were used to sample NOx produced by the chamber discharges- originally a Monitor Labs Model 8440E, later a Thermo Environment Model 42. Total NOx production for each discharge as well as NOx per ampere of current and NOx per Joule of discharge energy were plotted. Absolute NOx production was greatest for discharge environments with upper tropospheric pressures (100-380 torr), while NOx/J was greatest for discharge environments with stratospheric pressures (around 10 torr). The different production efficiencies in NOx/J as a function of pressure pointed to three different production regimes, each with its own reaction mechanisms: one for tropospheric pressures, one for stratospheric pressures, and one for upper stratospheric to mesospheric pressures (no greater than 1 torr).

  18. Nuclear power and the greenhouse effect

    International Nuclear Information System (INIS)

    Global levels of the ''Greenhouse'' gases - carbon dioxide, the chlorofluorocarbons (CFCs), methane, nitrous oxide and tropospheric ozone are increasing as a result of man's activities. This increase is widely expected to bring about a rise in global temperature with concomitant environmental impacts. Global warming has been observed over the last century, and the last decade has seen seven of the warmest years on record. There has also been increased variability in the weather (an expected consequence of global warming). However, these possible manifestations of the Greenhouse Effect are within natural variations and proof must await more definitive indications. A brief outline of current views on the Greenhouse Effect is given. This report addresses the energy sector using CO2 emissions as a measure of its ''Greenhouse'' contribution. This approach understates the energy sector contribution. However, the difference is within the error band. It seems likely that the warming effect of non-energy related emissions will remain the same and there will be more pressure to reduce the emissions from the energy sector. To assess policy options the pattern of future energy demand is estimated. Two scenarios have been adopted to provide alternative frameworks. Both assume low energy growth projections based on increased energy efficiency. The role of nuclear power in reducing carbon dioxide emissions is considered. (author)

  19. Professor Paul Crutzen, the winner of the Nobel prize: The discovery of the ozone hole - knowledge and vision; Nobelpreistraeger Prof. Paul Crutzen: Entdeckung des Ozonlochs - Wissen und Vision

    Energy Technology Data Exchange (ETDEWEB)

    Crutzen, P.; Dellert-Ritter, M.

    1997-02-01

    On 10 December 1995, Professor Crutzen was awarded the Nobel prize for his epoch-making achievements in the field of atmospheric chemistry. This award underlines also Professor Crutzen`s commitment to the protection of the atmosphere. The atmospheric researcher discovered how sensitively the ozone layer reacts to air pollution. His work, together with that of others, led to the ban on ozone-depleting chlorofluorocarbons. As early as in 1970, Professor Crutzen demonstrated that nitrogen oxides react catalytically with ozone. His think tank provided numerous stimuli for further, intense research on atmospheric chemistry, which triggered a debate on the protection of the thinning ozone layer also among politicians. (orig.) [Deutsch] Am 10. Dezember 1995 wurde Prof. Crutzen fuer seine bahnbrechenden Leistungen auf dem Gebiet der Atmosphaerenchemie mit dem Nobelpreis geehrt. Diese Anerkennung unterstreicht auch das Engagement von Prof. Crutzen zum Schutz der Ozonschicht. Der Atmosphaerenforscher Prof. Crutzen entdeckte, wie empfindlich die Ozonschicht auf Luftverunreinigungen reagiert. Seine Arbeiten fuehrten mit zum Verbot der ozonvernichtenden Fluorchlorkohlenwasserstoffe. Bereits 1970 wies Prof. Crutzen nach, dass Stickstoffoxide katalytisch mit Ozon reagieren. Aus der Ideenfabrik von Prof. Crutzen kamen zahlreiche Anregungen fuer weitere intensive Forschungen zur Chemie der Atmosphaere, die auch unter Politikern eine Debatte ueber den Schutz der hauchduennen Ozonschicht ausloeste. (orig.)

  20. Estimated historic emissions of fluorocarbons from the European Union

    Science.gov (United States)

    McCulloch, A.; Midgley, P. M.

    Emissions of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and one hydrofluorocarbon (HFC-134a) from Europe have been estimated for the years 1986-1996 with a precision in most cases better than ±20%. During that period, sales of CFCs have reduced to virtually zero but they are still being emitted from the "bank" in use in equipment. These emissions are calculated to have fallen dramatically; however the largest releases are still of CFC-11, at 44,000 tonnes in 1996. Significant contributions to the total emission of ozone depleting substances from the European Union during 1996 were also made by HCFC-22 (35,000 tonnes) and CFC-12 (9000 tonnes); releases of other CFCs and HCFCs into the atmosphere from the EU are markedly less. On the other hand, emissions of HFC-134a (which is not an ozone depleting substance) would appear to be growing rapidly and could have reached 12,000 tonnes yr -1 in 1996. HFC-134a is a replacement for CFC-12, releases of which are calculated to have declined much more than the growth in HFC-134a. This leads to the conclusion that substitution of one by the other has been much less than 100% and is actually smaller than had been projected by market research in the early 1990s.

  1. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Knorr Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO2 Sections A20_2003 (22 September-20 October 2003) and A22_2003 (23 October-13 November, 2003)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, Alex [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Carbon Dioxide Information Analysis Center

    2008-09-30

    This report presents methods, and analytical and quality control procedures for salinity, oxygen, nutrient, inorganic carbon, organic carbon, chlorofluorocarbon (CFC), and bomb carbon-14 system parameters performed during the A20_2003 and A22_2003 cruises, which took place between September 22 and November 13, 2003, aboard research vessel (R/V) Knorr under the auspices of the National Oceanic and Atmospheric Administration (NOAA) and National Science Foundation (NSF). The R/V Knorr departed Woods Hole, Massachusetts, on September 22 for the Repeat Section A20, and ended this line in Port of Spain, Trinidad, on October 20. The Repeat Section A22 started on October 23 in Port of Spain, Trinidad, and finished on November 13, 2003, in Woods Hole, Massachusetts. The research conducted was one of a series of repeat hydrography sections jointly funded by NOAA and NSF as part of the Climate Variability Program (CLIVAR)/CO2/repeat hydrography/tracer program. Samples were taken from 36 depths at 88 stations on section A20 and 82 stations on section A22. The data presented in this report include the analyses of water samples for total inorganic carbon (TCO2), total alkalinity (TALK), dissolved organic carbon (DOC), CFC, carbon-14, hydrographic, and other chemical measurements.

  2. Carbon dioxide, hydrographic, and chemical data obtained during the Thomas Washington Cruise TUNES-3 in the equatorial Pacific Ocean (WOCE Section P16C)

    Energy Technology Data Exchange (ETDEWEB)

    Goyet, C. [Woods Hole Oceanographic Institution, MA (United States); Guenther, P.R.; Keeling, C.D.; Talley, L.D. [Scripps Institution of Oceanography, La Jolla, CA (United States); Kozyr, A. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center

    1996-12-01

    This data documentation discusses the procedures and methods used to obtain total carbon dioxide (TCO{sub 2}), total alkalinity (TALK), hydrographic, and chemical data during the Research Vessel Thomas Washington Expedition TUNES-3 in the Equatorial Pacific Ocean (Section P16C). Conducted as a part of the World Ocean Circulation Experiment (WOCE), the cruise began in Papeete, Tahiti, on August 31, 1991, and finished in Honolulu, Hawaii, on October 1, 1991. WOCE Meridional Section P16C along 150{degree}W and between 18{degree}S and 19{degree}N was completed during the 31-day expedition. All 105 hydrographic and 8 large-volume stations were completed to the full water column depth. Station spacing was 30 nautical miles (nm), except between 3{degree}N and 3{degree}S where it was 10 nm. Twenty-five bio-optics stations were sampled for the Joint Global Ocean Flux Study, and at 21 stations carbon dioxide measurements were provided for the US Department of Energy`s CO{sub 2} program. Hydrographic and chemical measurements made along WOCE Section P16C included pressure, temperature, salinity, and oxygen measured by conductivity, temperature, and depth sensor; and bottle salinity, oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbon (CFC)-11, CFC-12, TCO{sub 2}, and TALK. In addition, potential temperatures were calculated from the measured variables.

  3. Carbon dioxide, hydrographic, and chemical data obtained during the R/V Thomas Washington TUNES-1 in the equatorial Pacific Ocean (WOCE Section P17C)

    Energy Technology Data Exchange (ETDEWEB)

    Goyet, C. [Woods Hole Oceanographic Institution, MA (United States); Key, R.M. [Princeton Univ., NJ (United States); Sullivan, K.F. [Univ. of Miami, FL (United States). Rosensteil School of Marine and Atmospheric Sciences; Tsuchiya, M. [Univ. of California, San Diego, CA (United States). Scripps Institution of Oceanography; Kozyr, A. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center]|[Univ. of Tennessee, Knoxville, TN (United States). Energy, Environment, and Resources Center

    1997-06-01

    This report discusses the procedures and methods used to obtain measurements of total carbon dioxide (TCO{sub 2}), total alkalinity (TALK), and radiocarbon ({Delta} {sup 14}C), as well as hydrographic and chemical data, during the Research Vessel Thomas Washington Expedition TUNES-1 in the Equatorial Pacific Ocean (Section P17C). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in San Diego, California, on May 31, 1991, and ended in Papeete, Tahiti, on July 11, 1991. WOCE Meridional Section P17C, along 135{degree}W and between {approximately}5{degree}S and 36{degree}N, was completed during the 42-day expedition. All 123 hydrographic stations (including 9 large-volume stations) were completed to the full water-column depth. Spacing between stations was 30 nautical miles, except between 3{degree}N and 3{degree}S, where it was 10 nautical miles. At 30 stations, CO{sub 2} measurements were provided for the US Department of Energy`s Carbon Dioxide Program. Hydrographic and chemical measurements made along WOCE Section P17C included pressure, temperature, salinity, and oxygen (measured by conductivity, temperature, and depth sensor), as well as bottle measurements of salinity, oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbon (CFC)-11, CFC-12, {Delta} {sup 14}C, TCO{sub 2}, and TALK. In addition, potential temperatures were calculated from the measured variables.

  4. Public perception of global warming and related environmental issues in Kano city, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Iliyasu, Z.; Abubakar, I.; Gajida, A.U.

    2010-07-01

    Sub-Saharan African countries are at an increased risk of the effects of global warming. Unfortunately they have the least capacity to adapt to its untoward effects. We studied public awareness of global warming, its perceived causes, effects and prevention in Kano city, northern Nigeria. Structured questionnaires were administered on a cross section of 181 adults in Kano eliciting their awareness of global warming, as well as perceived causes, effects and ways of prevention. Of the 181 respondents, 132 (72.9%) were aware of global warming mainly from electronic media (44.4%), the Internet (20.5%) and schools (18.7%). They mostly attributed it to air pollution (99.2%), use of fossil fuels (97.7%), toxic waste (78.0%) and chlorofluorocarbons (73.5%). Perceived effects of global warming include extremes of ambient temperature (97.7%), increased disease outbreaks (92.4%), floods (68.2%), droughts (51.5%) and loss of species (50.0%). Respondents opined that global warming could be prevented by using renewable sources of energy such as the sun (53.8%), massive tree planting (44.7%) and phasing out of old automobiles (43.2%). A significantly higher proportion of males, younger and educated respondents were aware of global warming. The high awareness about global warming needs to be reinforced through use of media to encourage advocacy and community action towards preventing global warming and ensuring environmental sustainability.

  5. Sorption Refrigeration / Heat Pump Cycles

    Science.gov (United States)

    Saha, Bidyut Baran; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Over the past few decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Up to now, only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the United States. Closed-type adsorption refrigeration and heat pump systems are rarely seen in the market, or are still in the laboratory testing stage. Promising recent development have been made in Japan for the use of porous metal hydrides and composite adsorbents. In this paper, a short description of adsorption theories along with an overview of present status and future development trends of thermally powered adsorption refrigeration cycles are outlined putting emphasis on experimental achievements. This paper also addressed some advanced absorption cycles having relatively higher COP, and also summarizes fundamental concepts of GAX cycles and various GAX cycles developed for heat pump applications.

  6. The nasal distribution of metered dose inhalers.

    Science.gov (United States)

    Newman, S P; Morén, P F; Clarke, S W

    1987-02-01

    The intranasal distribution of aerosol from a metered dose inhaler has been assessed using a radiotracer technique. Inhalers were prepared by adding 99Tcm-labelled Teflon particles (simulating the drug particles) to chlorofluorocarbon propellants, and scans of the head (and chest) taken with a gamma camera. Ten healthy subjects (age range 19-29 years) each performed two radioaerosol studies with the inhaler held in two different ways: either in a single position (vial pointing upwards) or in two positions (vial pointing upwards and then tilted by 30 degrees in the sagittal plane). The vast majority of the dose (82.5 +/- 2.8 (mean +/- SEM) per cent and 80.7 +/- 3.1 per cent respectively for one-position and two-position studies) was deposited on a single localized area in the anterior one-third of the nose, the initial distribution pattern being identical for each study. No significant radioaerosol was detected in the lungs. Only 18.0 +/- 4.7 per cent and 15.4 +/- 4.1 per cent of the dose had been removed by mucociliary action after 30 minutes, and it is probable that the remainder had not penetrated initially beyond the vestibule. Since the deposition pattern was highly localized and more than half the dose probably failed to reach the turbinates it is possible that the overall effect of nasal MDIs is suboptimal for the treatment of generalized nasal disorders.

  7. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Ronald H. Brown Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO2 Section A16S_2005 (11 January - 24 February, 2005)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, Alex [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Carbon Dioxide Information Analysis Center

    2006-08-30

    This report presents methods, and analytical and quality control procedures for salinity, oxygen, nutrient, inorganic carbon, organic carbon, chlorofluorocarbon (CFC), and bomb 14C system parameters performed during the A16S_2005 cruise, which took place from January 11 to February 24, 2005, aboard research vessel (R/V) Ronald H. Brown under the auspices of the National Oceanic and Atmospheric Administration (NOAA). The R/V Ronald H. Brown departed Punta Arenas, Chile, on January 11, 2005, and ended its cruise in Fortaleza, Brazil, on February 24, 2005. The research conducted was one of a series of repeat hydrography sections jointly funded by NOAA and the National Science Foundation as part of the CLIVAR/CO2/repeat hydrography/tracer program. Samples were taken from 36 depths at 121 stations. The data presented in this report include the analyses of water samples for total inorganic carbon (TCO2), fugacity of CO2 (fCO2), total alkalinity (TALK), pH, dissolved organic carbon (DOC), CFC, 14C, hydrographic, and other chemical measurements. The R/V Ronald H. Brown A16S_2005 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center (CDIAC). The NDP consists of the oceanographic data files and this printed documentation, which describes the procedures and methods used to obtain the data.

  8. Implications for human health of global atmospheric changes

    International Nuclear Information System (INIS)

    The possible impacts of the greenhouse effect, ozone depletion and ultraviolet irradiation, acid precipitation, and resulting demographic changes are reviewed, along with the implications of global ecological changes on society and sustainable development. Some manifestations of global warming caused by the greenhouse effect could include more frequently extreme weather conditions, rises in sea level, disruption of ocean currents, and changes in composition and distribution of vegetation. Consequences of these manifestations on human health include an increase in the frequency of droughts and heat waves, migration of disease carrying vectors to other areas, submergence of coastal areas and disruption of water supplies, destruction of tropical species potentially useful for medicinal purposes, and impaired production of crops leading to food shortages. Consequences of stratospheric ozone depletion due to chlorofluorocarbon pollution are thought to be a direct result of increased exposure to ultraviolet light; these consequences include higher risks of non-melanoma skin cancer. The effects of acid precipitation are thought to be primarily ecological and indirect. 61 refs,

  9. GLODAPv2 data exploration and extraction system

    Science.gov (United States)

    Krassovski, Misha; Kozyr, Alex; Boden, Thomas

    2016-04-01

    The Global Ocean Data Analysis Project (GLODAP) is a cooperative effort of investigators funded for ocean synthesis and modeling projects by the U.S. National Oceanic and Atmospheric Administration (NOAA), Department of Energy (DOE), and National Science Foundation (NSF). Cruises conducted as part of the WOCE, JGOFS, and NOAA Ocean-Atmosphere Carbon Exchange Study (OACES) over the decade of the 1990s generated oceanographic data of unparalleled quality and quantity. GLODAPv2 is a uniformly calibrated open-ocean data product containing inorganic carbon and carbon-relevant variables. This new product includes data from approximately one million individual seawater samples collected from over 700 cruises during the period 1972-2013. Extensive quality control and subsequent calibration were carried out for salinity, oxygen, nutrient, carbon dioxide, total alkalinity, pH, and chlorofluorocarbon data. The Carbon Dioxide Information and Analysis Center (CDIAC), serving as the primary DOE disseminator for climate data and information, developed database and web accessible systems that permit users worldwide to query and retrieve data from the GLODAPv2 collection. This presentation will showcase this new system, discuss technologies used to build the GLODAPv2 resource, and describe integration with a metadata search engine provided by CDIAC as well.

  10. Precision Cleaning Verification of Nonvolatile Residues by Using Water, Ultrasonics, and Turbidity Analyses

    Science.gov (United States)

    Skinner, S. Ballou

    1991-01-01

    Chlorofluorocarbons (CFC's) in the atmosphere are believed to present a major environmental problem because they are able to interact with and deplete the ozone layer. NASA has been mandated to replace chlorinated solvents in precision cleaning, cleanliness verification, and degreasing of aerospace fluid systems hardware and ground support equipment. KSC has a CFC phase-out plan which provides for the elimination of over 90 percent of the CFC and halon use by 1995. The Materials Science Laboratory and KSC is evaluating four analytical methods for the determination of nonvolatile residues removal by water: (1) infrared analyses using an attenuated total reflectance; (2) surface tension analyses, (3) total organic content analyses, and (4) turbidity analyses. This research project examined the ultrasonic-turbidity responses for 22 hydrocarbons in an effect to determine: (1) if ultrasonics in heated water (70 C) will clean hydrocarbons (oils, greases, gels, and fluids) from aerospace hardware; (2) if the cleaning process by ultrasonics will simultaneously emulsify the removed hydrocarbons in the water; and (3) if a turbidimeter can be used successfully as an analytical instrument for quantifying the removal of hydrocarbons. Sixteen of the 22 hydrocarbons tested showed that ultrasonics would remove it at least 90 percent of the contaminated hydrocarbon from the hardware in 10 minutes or less giving a good ultrasonic-turbidity response. Six hydrocarbons had a lower percentage removal, a slower removal rate, and a marginal ultrasonic-turbidity response.

  11. What prevents outgassing of methane to the atmosphere in Lake Tanganyika?

    Science.gov (United States)

    Durisch-Kaiser, Edith; Schmid, Martin; Peeters, Frank; Kipfer, Rolf; Dinkel, Christian; Diem, Torsten; Schubert, Carsten J.; Wehrli, Bernhard

    2011-06-01

    Tropical East African Lake Tanganyika hosts the Earth's largest anoxic freshwater body. The entire water column holds over 23 Tg of the potent greenhouse gas methane (CH4). Methane is formed under sulphate-poor conditions via carbon dioxide reduction or fermentation from detritus and relict sediment organic matter. Permanent density stratification supports an accumulation of CH4 below the permanent oxycline. Despite CH4 significance for global climate, anaerobic microbial consumption of CH4 in freshwater is poorly understood. Here we provide evidence for intense methanotrophic activity not only in the oxic but also in the anoxic part of the water column of Lake Tanganyika. We measured CH4, 13C of dissolved CH4, dissolved oxygen (O2), sulphate (SO42-), sulphide (HS-) and the transient tracers chlorofluorocarbon-12 (CFC-12) and tritium (3H). A basic one-dimensional model, which considers vertical transport and biogeochemical fluxes and transformations, was used to interpret the vertical distribution of these substances. The results suggest that the anaerobic oxidation of CH4 is an important mechanism limiting CH4 to the anoxic zone of Lake Tanganyika. The important role of the anaerobic oxidation for CH4 concentrations is further supported by high abundances (up to ˜33% of total DAPI-stained cells) of single living archaea, identified by fluorescence in situ hybridization.

  12. TRENDS 1991: A compendium of data on global change

    Energy Technology Data Exchange (ETDEWEB)

    Boden, T.A.; Sepanski, R.J.; Stoss, F.W. (eds.)

    1991-12-01

    This document is a source of frequently used global-change data. This second issue of the Trends series expands the coverage of sites recording atmospheric concentrations of carbon dioxide (CO{sub 2}) and methane (CH{sub 4}), and it updates records reported in the first issue. New data for other trace atmospheric gases have been included in this issue; historical data on nitrous oxide (N{sub 2}) from ice cores, modern records of atmospheric concentrations of chlorofluorocarbons (CFC-11 and CFC-12) and N{sub 2}O, and estimates of global estimates of CFC-11 and CFC-12. The estimates for global and national CO{sub 2} emissions from the burning of fossil fuels, the production of cement, and gas flaring have been revised and updated. Regional CO{sub 2} emission estimates have been added, and long-term temperature records have been updated and expanded. Data records are presented in four- to six-page formats, each dealing with a specific site, region, or emissions species. The data records include tables and graphs; discussion of methods for collecting, measuring, and reporting the data; trends in the data; and references to literature that provides further information. All data appearing in the document are available on digital media from the Carbon Dioxide Information Analysis Center.

  13. Global Warming in the Twenty-First Century: An Alternative Scenario

    Science.gov (United States)

    Hansen, James; Sato, Makiko; Ruedy, Reto; Lacis, Andrew; Oinas, Valdar

    2000-01-01

    A common view is that the current global warming rate will continue or accelerate. But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols, the positive and negative climate forcings of which are partially offsetting. The growth rate of non-CO2 GHGs has declined in the past decade. If sources of CH4 and O3 precursors were reduced in the future, the change in climate forcing by non-CO2 GHGs in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions, this reduction of non-CO2 GHGs could lead to a decline in the rate of global warming, reducing the danger of dramatic climate change. Such a focus on air pollution has practical benefits that unite the interests of developed and developing countries. However, assessment of ongoing and future climate change requires composition specific long-term global monitoring of aerosol properties.

  14. Atmospheric Consequences of Cosmic Ray Variability in the Extragalactic Shock Model

    CERN Document Server

    Melott, A L; Thomas, B C; Medvedev, M V; Wilson, G W; Murray, M J

    2008-01-01

    It has been suggested that galactic shock asymmetry induced by our galaxy infall toward the Virgo Cluster may be a source of periodicity in cosmic ray exposure as the solar system oscillates normal to the galactic plane, thereby inducing an observed terrestrial periodicity in biodiversity. Here we investigate one possible mechanism, the ionization and dissociation in the atmosphere, resulting in changes in atmospheric chemistry which culminate in the depletion of ozone and a resulting increase in the dangerous solar UVB flux on the ground. We estimate the enhancement of cosmic ray intensity for a range of reasonable parameters of the galactic wind and galactic magnetic field, and use these to compute steady-state atmospheric effects. At the lower end of this range, we find that the effects are far too small to be of serious consequence. At the upper end of this range, the level of ozone depletion approaches that currently experienced due to anthropogenic effects such as accumulated chlorofluorocarbons, i.e. ~...

  15. Emissions of greenhouse gases in the United States 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    This is the fourth Energy Information Administration (EIA) annual report on US emissions of greenhouse gases. This report presents estimates of US anthropogenic (human-caused) emissions of carbon dioxide, methane, nitrous oxide, and several other greenhouse gases for 1988 through 1994. Estimates of 1995 carbon dioxide, nitrous oxide, and halocarbon emissions are also provided, although complete 1995 estimates for methane are not yet available. Emissions of carbon dioxide increased by 1.9% from 1993 to 1994 and by an additional 0.8% from 1994 to 1995. Most carbon dioxide emissions are caused by the burning of fossil fuels for energy consumption, which is strongly related to economic growth, energy prices, and weather. The US economy grew rapidly in 1994 and slowed in 1995. Estimated emissions of methane increased slightly in 1994, as a result of a rise in emissions from energy and agricultural sources. Estimated nitrous oxide emissions increased by 1.8% in 1995, primarily due to increased use of nitrogen fertilizers and higher output of chemicals linked to nitrous oxide emissions. Estimated emissions of hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), which are known to contribute to global warming, increased by nearly 11% in 1995, primarily as a result of increasing substitution for chlorofluorocarbons (CFCs). With the exception of methane, the historical emissions estimates presented in this report are only slightly revised from those in last year`s report.

  16. Halocarbon ozone depletion and global warming potentials

    Science.gov (United States)

    Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.

    1990-01-01

    Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming).

  17. On the age of stratospheric air and ozone depletion potentials in polar regions

    Science.gov (United States)

    Pollock, W. H.; Heidt, L. E.; Lueb, R. A.; Vedder, J. F.; Mills, M. J.; Solomon, S.

    1992-01-01

    Observations of the nearly inert, man-made chlorofluorocarbon CFC-115 obtained during January 1989 are used to infer the age of air in the lower stratosphere. These observations together with estimated release rates suggest an average age of high-latitude air at pressure altitudes near 17-21 km of about 3 to 5 yr. This information is used together with direct measurements of HCFC-22, HCFC-142b, CH3Br, H-1301, H-1211, and H-2402 to examine the fractional dissociation of these species within the Arctic polar lower stratosphere compared to that of CFC-11 and hence to estimate their local ozone depletion potentials in this region. It is shown that these HCFCs are much less efficiently dissociated within the stratosphere than CFC-11, lowering their ozone depletion potentials to only about 30-40 percent of their chlorine loading potentials. In contrast, the observations of CH3Br and the Halons considered confirm that they are rapidly dissociated within the stratosphere, with important implications for their ozone depletion potentials.

  18. The Antarctic ozone depletion caused by Erebus volcano gas emissions

    Science.gov (United States)

    Zuev, V. V.; Zueva, N. E.; Savelieva, E. S.; Gerasimov, V. V.

    2015-12-01

    Heterogeneous chemical reactions releasing photochemically active molecular chlorine play a key role in Antarctic stratospheric ozone destruction, resulting in the Antarctic ozone hole. Hydrogen chloride (HCl) is one of the principal components in these reactions on the surfaces of polar stratospheric clouds (PSCs). PSCs form during polar nights at extremely low temperatures (lower than -78 °C) mainly on sulfuric acid (H2SO4) aerosols, acting as condensation nuclei and formed from sulfur dioxide (SO2). However, the cause of HCl and H2SO4 high concentrations in the Antarctic stratosphere, leading to considerable springtime ozone depletion, is still not clear. Based on the NCEP/NCAR reanalysis data over the last 35 years and by using the NOAA HYSPLIT trajectory model, we show that Erebus volcano gas emissions (including HCl and SO2) can reach the Antarctic stratosphere via high-latitude cyclones with the annual average probability Pbarann. of at least ∼0.235 (23.5%). Depending on Erebus activity, this corresponds to additional annual stratospheric HCl mass of 1.0-14.3 kilotons (kt) and SO2 mass of 1.4-19.7 kt. Thus, Erebus volcano is the natural and powerful source of additional stratospheric HCl and SO2, and hence, the cause of the Antarctic ozone depletion, together with man-made chlorofluorocarbons.

  19. TRENDS 1991: A compendium of data on global change

    International Nuclear Information System (INIS)

    This document is a source of frequently used global-change data. This second issue of the Trends series expands the coverage of sites recording atmospheric concentrations of carbon dioxide (CO2) and methane (CH4), and it updates records reported in the first issue. New data for other trace atmospheric gases have been included in this issue; historical data on nitrous oxide (N2) from ice cores, modern records of atmospheric concentrations of chlorofluorocarbons (CFC-11 and CFC-12) and N2O, and estimates of global estimates of CFC-11 and CFC-12. The estimates for global and national CO2 emissions from the burning of fossil fuels, the production of cement, and gas flaring have been revised and updated. Regional CO2 emission estimates have been added, and long-term temperature records have been updated and expanded. Data records are presented in four- to six-page formats, each dealing with a specific site, region, or emissions species. The data records include tables and graphs; discussion of methods for collecting, measuring, and reporting the data; trends in the data; and references to literature that provides further information. All data appearing in the document are available on digital media from the Carbon Dioxide Information Analysis Center

  20. Residence time distribution in a large unconfined-semiconfined aquifer in the Argentine Pampas using 3H/3He and CFC tracers

    Science.gov (United States)

    Martínez, D. E.; Fourré, E.; Londoño, O. M. Quiroz; Jean-Baptiste, P.; Galli, M. Glok; Dapoigny, A.; Grondona, S. I.

    2016-08-01

    The Pampa region in Argentina includes vast unconfined-semiconfined aquifers that local economies depend upon, but detailed knowledge of the associated water resources is still lacking. The Pampeano aquifer in the Pampa plain of Argentina covers around 1.5 million km2. In order to achieve a better understanding of the hydrogeological system through the estimation of mean residence times (MRT), water samples were taken from 12 monitoring wells, drilled at different depths in four locations, and analyzed for environmental tracers. The concentrations of 3H, tritiogenic 3He and chlorofluorocarbons (CFCs) can be explained by mixtures of young waters adjusted to exponential piston flow models (EPM) or dispersion models (DM), and different proportions of tracer-free waters (dead water). The sampling site located very close to the water divide shows a dominance of young waters: 85 % of water best represented by a DM model with a MRT of 3 years. For the shallow wells at other sites, best-fitting models result in a DM with MRT between 20 and 35 years, and proportions of dead water between 40 and 60 %. These results lead to important updates in the conceptual model of the Pampeano aquifer. Large proportions of dead water at a few meters depth can be the consequence of upward flows in a multilayered aquifer or diffusive retardation in the inter-bedded clay layers.

  1. Theoretical Study on CO2 Transcritical Cycle Combined Ejector Cycle Refrigeration System

    Institute of Scientific and Technical Information of China (English)

    卢苇; 马一太; 李敏霞; 查世彤

    2003-01-01

    Chlorofluorocarbons(CFCs) or hydrochlorofluorocarbons(HCFCs) are as main refrigerants used in traditional refrigeration systems driven by electricity from burning fossil fuels, which is regarded as one of the major reasons for ozone depletion (man-made refrigerants emission) and global warming (CO2 emission). So people pay more and more attention to natural refrigerants and energy saving technologies. An innovative system combining CO2 transcritical cycle with ejector cycle is proposed in this paper. The CO2 compression sub-cycle is powered by electricity with the characteristics of relatively high temperature in the gas cooler (defined as an intercooler by the proposed system). In order to recover the waste heat, an ejector sub-cycle operating with the natural refrigerants (NH3, H2O) is employed. The two sub-cycles are connected by an intercooler. This combined cycle joins the advantages of the two cycles together and eliminates the disadvantages. The influences of the evaporation temperature in CO2 compression sub-cycle, the evaporation temperature in the ejector sub-cycle, the temperature in the intercooler and the condensation temperature in the proposed system performance are discussed theoretically in this study. In addition, some unique features of the system are presented.

  2. The technical viability of alternative blowing agents in polyisocyanurate roof insulation: A cooperative industry/government project

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.; Courville, G.E.; Desjarlais, A.O.; Graves, R.S.; Linkous, R.L.; McElroy, D.L.; Weaver, F.J.; Wendt, R.L.; Yarbrough, D.W.

    1993-06-01

    This report is a summary of the cooperative industry/government program to establish the viability of alternative blowing agents to chlorofluorocarbons (CFCs). The project was initiated in 1989 following two workshops that focused on needed research on thermal insulation blown with substitutes for CFC-11 and CFC-12. The project is directed by a steering committee of representatives of the sponsors and of Oak Ridge National Laboratory (ORNL). The purpose of the project is to determine if the performance of polyisocyanurate (PIR) roof insulation foam boards blown with alternate agents differs from the performance of boards blown with CFC-1. This report describes apparent thermal conductivity (k) results obtained from field and laboratory tests from 1989 to 1992 on a set of experimental PIR laminate boardstock produced to evaluate the viability of alternative hydrochlorofluorocarbons (HCFCs) as blowing agents. All boardstock was manufactured from similar formulations that were not optimized for thermal performance. Commercial broadstock made in the future may differ in performance from this set. The PIR boards were prepared with CFC-11, HCFC-123, HCFC-141b, and 50/50 and 65/35 blends of HCFC-123/HCFC-141b.

  3. Polar stratospheric ozone: interactions with climate change, results from the EU project RECONCILE, and the 2010/11 Arctic ozone hole

    Science.gov (United States)

    von Hobe, Marc

    2013-04-01

    One of the most profound and well known examples of human impacts on atmospheric chemistry is the so called ozone hole. During the second half of the 20th century, anthropogenic emissions of chlorofluorocarbons (CFCs) led to a significant increase in stratospheric chlorine levels and hence the rate of ozone removal by catalytic cycles involving chlorine. While CFCs were essentially banned by the 1987 Montreal Protocol and its subsequent amendments, and stratospheric chlorine levels have recently started to decline again, another anthropogenic influence may at least delay the recovery of the stratospheric ozone layer: climate change, with little doubt a result of human emissions of carbon dioxide and other greenhouse gases, has led to changes in stratospheric temperature and circulation. The large ozone losses that typically occur in polar regions in spring are particularly affected by these changes. Here, we give an overview of the ozone-climate interactions affecting polar stratospheric ozone loss, and present latest results from the international research project RECONCILE funded by the European Commission. Remaining open questions will be discussed including the possible impacts of recently suggested geoengineering concepts to artificially enhance the stratospheric aerosol loading. A special focus will also be put on the 2010/11 Arctic winter that saw the first Arctic Ozone hole, including an impact study on surface UV radiation in the densely populated northern mid-latitudes.

  4. Light and skin disease

    International Nuclear Information System (INIS)

    Because of the depletion of ozone in the stratosphere due to chlorofluorocarbons, the screening effect of this ozone layer on ultraviolet radiation (especially the so-called UV-B component) is reduced. This paper describes the impact of increased UV radiation on the human skin. Because of the 'ozone-hole', a distinct increase in the rate of skin cancer is to be expected which will affect all living beings but most of all man - an indirect consequence of the climate development. What makes the increased intensity of UV-B radiation so harmful is the fact that light-induced skin damage accumulates for the period of the life-time of the individual and cannot be reversed. A further thinning of stratospheric ozone would let through, in addition, the more short-waved ('harder') UV-C radiation. The latter, though clinically not significant currently, would then account for a further increase in the rate of malignant skin disease world-wide. (orig.)

  5. Introduction

    Science.gov (United States)

    Waugh, Darryn W.; Polvani, Lorenzo M.

    Over the past few decades there has been intensive research into the Earth's stratosphere, which has resulted in major advances in our understanding of its dynamics, transport, and chemistry and its coupling with other parts of the atmosphere. This interest in the stratosphere was originally motivated by concerns regarding the stratospheric ozone layer, which plays a crucial role in shielding Earth's surface from harmful ultraviolet light. In the 1980s the depletion of ozone was first observed, with the Antarctic ozone hole being the most dramatic example, and then linked to increases in chlorofluorocarbons (CFCs). These findings led to the signing of the Montreal Protocol, which regulates the production of CFCs and other ozone-depleting substances. Over the subsequent decades, extensive research has led to a much better understanding of the controls on stratospheric ozone and the impact of changes in CFC abundance (including the recovery of the ozone layer as the abundance of CFCs returns to historical levels). More recently, there has been added interest in the stratosphere because of its potential impact on surface climate and weather. This surface impact involves changes in the radiative forcing, the flux of ozone and other trace constituents into the troposphere, and dynamical coupling.

  6. [Experimental studies on the recovery of anesthetic gases].

    Science.gov (United States)

    Marx, T; Gross-Alltag, F; Ermisch, J; Hähnel, J; Weber, L; Friesdorf, W

    1992-02-01

    The volatile anesthetic agents halothane, enflurane, and isoflurane are chlorofluorocarbons (CFC) and contribute to ozone depletion. Although the contribution is small, its importance is rising, as technical CFCs will be phased out according to the Montreal protocol (1987) and the London conference (1990) by the year 2000. Alternative procedures and CFC-free volatile agents such as des- and sevoflurane do not contribute to depletion of the ozone layer, but will not replace standard methods using volatile anesthetic agents in the near future. METHODS. In an experimental setup, we filtered anesthetic waste gases from scavenging systems of rebreathing circles by activated carbon filters. The filtered substances were desorbed by a heat chamber and condensed in a cold trap. RESULTS. By this method, it was possible to retrieve 50%-60% of the applied gases. Gas chromatographic analysis showed halothane containing traces of pollutants and isoflurane and enflurane as pure substances. DISCUSSION. The retrieval of anesthetic waste gases is easy; no sophisticated technical equipment is necessary. Purity of substances could make recycling possible and offer a method to avoid environmental pollution by volatile anesthetics. PMID:1562100

  7. Climate change and transnational corporations. Analysis and trends

    International Nuclear Information System (INIS)

    In Economic and Social Council resolution 1989/25, the Council requested an analytic study of the main sectors of activity that have adverse effects on environmental preservation and the factors that determine the allocation of activities between developed and developing countries. The present report, entitled Climate Change and Transnational Corporations: Analysis and Trends, is in response to that request. The problem of global warming and the dangers it presents to global survival are being given high priority by the United Nations. Discussions are under way leading to a convention on global climate change under the auspices of United Nations intergovernmental bodies. The study was designed as a contribution to that process. It focuses on six transnational energy-producing and energy-consuming industrial sectors, in which corporate practices have a direct and major impact on the problems associated with global climate change. The sectors are fossil fuel production, transportation, electricity-generation, energy-intensive metals production, chlorofluorocarbons and other ozone-depleting chemicals, and inorganic nitrogen fertilizers. The study explores the relative differential impacts between industrialized and developing countries of each sector, and asks how each sector would have to be restructured in order to limit global climate change and ozone depletion. It concludes that major changes in the technical processes and investment patterns of the transnational corporations in those sectors would be necessary if catastrophic environmental changes are to be avoided

  8. An evaluation on the environmental consequences of residual CFCs from obsolete household refrigerators in China

    International Nuclear Information System (INIS)

    Chlorofluorocarbons (CFCs) contained in household refrigerators consist mainly of CFC-11 and CFC-12, which will be eventually released into the environment. Consequentially, environmental releases of these refrigerants will lead to ozone depletion and contribute significantly to the greenhouse effect, if waste refrigerators are not disposed of properly. In the present paper, the potential release of residual CFCs and their substitutes from obsolete household refrigerators in China is examined, and their contributions to ozone depletion and greenhouse effect are compared with those of other recognized ozone-depleting substances (ODS) and greenhouse gases (GHGs). The results imply that annual potential amounts of released residual CFC-11 and CFC-12 will reach their maximums at 4600 and 2300 tons, respectively in 2011, and then decrease gradually to zero until 2020. Meanwhile, the amounts of their most widely used substitutes HCFC-141b and HFC-134a will keep increasing. Subsequently, the contribution ratio of these CFCs and their substitutes to ozone depletion will remain at 25% through 2011, and reach its peak value of 34% by 2018. The contribution to greenhouse effect will reach its peak value of 0.57% by 2010. Moreover, the contribution ratio of these CFCs to the total global release of CFCs will steadily increase, reaching its peak of 15% by 2018. Thus, this period from 2010 to 2018 is a crucial time during which residual CFCs and their substitutes from obsolete household refrigerators in China will contribute significantly to ozone depletion.

  9. Experimental Study on a Stirling Cycle Machine of 100W Design Capacity

    Science.gov (United States)

    Otaka, Toshio; Kodama, Itaru; Ota, Masahiro

    Environmental concerns are causing commonly used chlorofluorocarbon (CFC) refrigerants to be phased out of production. The less ozone-depleting HCFC's are regulating. The green house effecting HFC's are also likely to be regulated and banned in the next period. Accordingly, attention is drawn to the Stirling refrigerator, which is a perfect Freon free refrigerator. Moreover, The Stirling cycle has the highest theoretical cycle efficiency corresponding to the value of the Carnot cycle among the proposed thermodynamic cycles. The green house effect by carbon dioxide issue would make better recognizing the importance of efficient use of energy in terms of high energy conservation measures. The authors have designed and developed a 100 W class Stirling refrigerator for household use. And the prototype machine has been integrated with a 100 litter class refrigerator. The operating characteristics of this Stirling unit or the prototype machine have been evaluated. Moreover, the authors evaluated the machine driving engine mode using ultra-low temperature media. As a result, the operational characteristics of the Stirling cycle machine have been clarified with respect to design factors. These results demonstrate that the Stirling cycle machine is one of the promising candidates as a new refrigeration system or a new generation system.

  10. Creation of an artificial ionized layer in the atmosphere by microwave nanosecond radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vikharev, A.L.; Ivanov, O.A.; Litvak, A.G. [Russian Academy of Science, Nizhny Novgorod (Russian Federation). Inst. of Applied Physics

    1995-12-31

    The paper reviews recent results of IAP microwave discharge group in investigation of a pulse-periodical nanosecond microwave discharges in converging wave beams. Performed experiments are the laboratory modeling of plasma chemical kinetics in an artificial ionized layer (AIL) created in the atmosphere by microwave beams using a ground-based transmitters. The interest to the AIL is explained by the variety of tasks which can be solved with its help. At present there are suggestions to use AIL for: distant radio- and television communication, generation of ozone, diagnostics of atmosphere, clearing of atmosphere from pollution. For the first time the possibility of using a nanosecond microwave discharge in wave beams to replenish the ozone decrease in the region of local ``ozone holes`` has been demonstrated experimentally. The regimes of effective ozone generation with low expenditure of energy have been defined. The efficiency of chlorofluorocarbons (freon) destruction has been defined with the help of AIL in troposphere at the heights of 10--20 km on the basis of laboratory measurements of plasma decay rate of a nanosecond microwave discharge. It has been experimentally shown that if the concentration of the atmosphere freon surpasses the threshold value then it is destroyed quickly in the processes of dissociative attachment of electrons.

  11. A manual for a Laboratory Information Management System (LIMS) for light stable isotopes

    Science.gov (United States)

    Coplen, Tyler B.

    1998-01-01

    The reliability and accuracy of isotopic data can be improved by utilizing database software to (i) store information about samples, (ii) store the results of mass spectrometric isotope-ratio analyses of samples, (iii) calculate analytical results using standardized algorithms stored in a database, (iv) normalize stable isotopic data to international scales using isotopic reference materials, and (v) generate multi-sheet paper templates for convenient sample loading of automated mass-spectrometer sample preparation manifolds. Such a database program is presented herein. Major benefits of this system include (i) an increase in laboratory efficiency, (ii) reduction in the use of paper, (iii) reduction in workload due to the elimination or reduction of retyping of data by laboratory personnel, and (iv) decreased errors in data reported to sample submitters. Such a database provides a complete record of when and how often laboratory reference materials have been analyzed and provides a record of what correction factors have been used through time. It provides an audit trail for stable isotope laboratories. Since the original publication of the manual for LIMS for Light Stable Isotopes, the isotopes 3 H, 3 He, and 14 C, and the chlorofluorocarbons (CFCs), CFC-11, CFC-12, and CFC-113, have been added to this program.

  12. A review of vacuum insulation research and development in the Building Materials Group of the Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kollie, T.G.; McElroy, D.L.; Fine, H.A.; Childs, K.W.; Graves, R.S.; Weaver, F.J.

    1991-09-01

    This report is a summary of the development work on flat-vacuum insulation performed by the Building Materials Group (BMG) in the Metals and Ceramics Division of the Oak Ridge National Laboratory (ORNL) during the last two years. A historical review of the technology of vacuum insulation is presented, and the role that ORNL played in this development is documented. The ORNL work in vacuum insulation has been concentrated in Powder-filled Evacuated Panels (PEPs) that have a thermal resistivity over 2.5 times that of insulating foams and seven times that of many batt-type insulations, such as fiberglass. Experimental results of substituting PEPs for chlorofluorocarbon (CFC) foal insulation in Igloo Corporation ice coolers are summarized. This work demonstrated that one-dimensional (1D) heat flow models overestimated the increase in thermal insulation of a foam/PEP-composite insulation, but three-dimensional (3D) models provided by a finite-difference, heat-transfer code (HEATING-7) accurately predicted the resistance of the composites. Edges and corners of the ice coolers were shown to cause the errors in the 1D models as well as shunting of the heat through the foam and around the PEPs. The area of coverage of a PEP in a foam/PEP composite is established as an important parameter in maximizing the resistance of such composites. 50 refs., 27 figs,. 22 tabs.

  13. Fluorinated ethers: A new series of CFC substitutes. Rept. for Aug 88-Oct 91

    International Nuclear Information System (INIS)

    The paper discusses fluorinated ethers, a new series of chlorofluorocarbon (CFC) substitutes. Compounds synthesized to produce substances with suitable refrigerant properties have generally left out sulfur, nitrogen, and oxygen. The general result is that all currently proposed substitutes for CFC and halon replacements have been alkanes. Because of the limited number of compounds of these elements having suitable properties and the current decision to phase out CFCs and (eventually) hydrochlorofluorocarbons (HCFCs), restricting the search to alkanes only is no longer tenable. Consideration of fluorinated ethers effectively doubles the potential list of contenders. The fact that divalent oxygen in a fluorocarbon chain has only a modest effect on vapor pressure, compared to the alkane of similar carbon number and substitution, should be a strong incentive to investigate these compounds. Several new fluorinated compounds have been synthesized and characterized. Additionally, several compounds for which data were not available were synthesized. These compounds, both new and two 'revisited' ones, could function as replacement working fluids in many applications requiring similar properties. Without chlorine, all have zero ozone depletion potential

  14. Refrigeration CFC's recovery, reuse, alternatives and new legislation

    International Nuclear Information System (INIS)

    The industrialized nations of the world met in 1986 in Vienna, Austria, to discuss curbs on the production of chlorofluorocarbons (CFCs). Scientists had determined that these compounds, typically used as refrigerants, were accumulating in the upper layers of the earth's atmosphere. The chlorine atoms in the compounds were catalytically converting ozone in the stratosphere to oxygen, effectively reducing ozone levels. Ozone in the stratosphere serves as a protective shield, reflecting ultraviolet radiation (UV) from the sun from striking the earth's surface. The loss of this protective shield would result in increased UV radiation levels. Plant growth on land and plankton production in the seas would be stunted, altering the food chain. Severe climatic changes would also result. At the initial meeting in Vienna, and at a subsequent meeting in Montreal, the industrialized nations agreed to limit the production of CFCs based on 1986 worldwide production levels. This paper examines alternatives to the use of CFCs, their recovery and reuse, and new legislation governing their use

  15. Ozone Depletion Potentials of HCFC-123 and HCFC-124

    Science.gov (United States)

    Riepe, E. L.; Patten, K. O.; Wuebbles, D. J.

    2005-05-01

    The Montreal Protocol has phased out most chlorinated and brominated compounds because of their great efficiency in depleting ozone in the stratosphere. Compounds such as CHCl2CF3 (HCFC-123) and CHClFCF3 (HCFC-124) are being used in commercial refrigeration units and have much shorter atmospheric lifetimes than the chlorofluorocarbons they replace. Despite their small resulting Ozone Depletion Potentials (ODPs), these compounds are still currently expected to be eliminated under the existing Protocol, but there remain questions about finding suitable replacements that would not have other environmental effects. The HCFC-123 and HCFC-124 model-calculated atmospheric lifetimes of 1.3 years and 5.8 years are much shorter compared to the 45 years of CCl3F (CFC-11). In this study, we have reevaluated these compounds with an updated version of the UIUC two-dimensional chemical transport model and with the MOZART (version 3) three-dimensional chemical-transport model. The new version of the two-dimensional model gives ODPs of 0.012 and 0.0125 for HCFC-123 and HCFC-124, respectively. The ODP for HCFC-123 agrees well with previously reported values while the ODP for HCFC-124 is much smaller than earlier estimates. These analyses along with those from the three-dimensional modeling studies will be discussed in the presentation.

  16. Global warming impacts of CFC alternative technologies: Combining fluorocarbon and CO2 effects

    International Nuclear Information System (INIS)

    Chlorofluorocarbons (CFCs) are on their way out, due to their role in stratospheric ozone depletion and the related international Montreal Protocol agreement and various national phaseout timetables. As the research, engineering development, and manufacturing investment decisions have ensued to prepare for this transition away from CFCs, the climate change issue has emerged and there has recently been increased attention on the direct global warming potential (GWP) of the fluorocarbon alternatives as greenhouse gases. However, there has been less focus on the indirect global warming effect arising from end-use energy changes and associated CO2 emissions. A study was undertaken to address these combined global warming effects. A concept of Total Equivalent Warming Impact (TEWI) was developed for combining the direct and indirect effects and was used for evaluating CFC-replacement options available in the required CFC transition time frame. Analyses of industry technology surveys indicate that CFC-user industries have made substantial progress toward near-equal energy efficiency with many HCFC/HFC alternatives. The findings also bring into question the relative importance of the direct effect in many applications and stress energy efficiency when searching for suitable CFC alternatives. For chillers, household refrigerators, and unitary air-conditioning or heat pump equipment, changes in efficiency of only 2--5% would have a greater effect on future TEWI than completely eliminating the direct effect

  17. The role of refrigerants in climate change

    International Nuclear Information System (INIS)

    The primary chemicals used as refrigerants, chlorofluorocarbons (CFCs), and the compounds being considered as their replacements (HCFCs and HFCs) have been intensely studied because of concerns about chlorine chemistry effects on stratospheric ozone. Increasing attention is being given to the potential effects of these compounds in concerns about global warming. CFCs, HCFCs, and HFCs absorb infrared radiation and thus are greenhouse gases that can influence radiative forcing on climate. The purpose of this paper is to describe the current understanding of the role of refrigerants in affecting climate. Increasing atmospheric concentrations of CFCs have accounted for about 24 % of the direct increase in radiative forcing from greenhouse gases over the last decade. However, observed decreases in stratospheric ozone, thought to be connected to increasing stratospheric chlorine from CFCs, suggests a cooling tendency over the last decade. This cooling tendency has strong latitudinal gradients, but is, when globally averaged, about comparable in magnitude and opposite in sign to the radiative forcing from CFCs over this period. Because of their shorter atmospheric lifetimes, the direct radiative influence on climate from the replacement compounds should generally be much smaller than the CFCs

  18. Environmental tradeoffs between CFCs and alternative refrigerants

    International Nuclear Information System (INIS)

    In 1987, an international group of scientists and government officials established the Montreal Protocol, an agreement to control the use and release of chlorofluorocarbons (CFCs), and to schedule a timeline for eliminating their production. This agreement is a historic step in the ongoing process of building consensus regarding environmental impacts of CFCs. This paper reports on the Montreal Protocol and provisions of the 1990 Clean Air Act which specify schedules for phasing out CFC production. For either schedule, all CFCs are to be eliminated from production by the year 2000. In addition, the hydrochlorofluorocarbons (HCFCs) are likely to face similar restrictions, but probably not for another 25 years. An aggressive tax on CFCs accompanies the phase-out schedule. This tax applies to existing supplier floorstock as well as new production. The results of taxes and regulations are that CFCs users must pay a premium price and may face availability problems. The users of CFC-based air conditioning and refrigeration equipment will have to consider their options and, eventually, will have to install alternative refrigerants or systems

  19. Global warming impacts of chillers

    International Nuclear Information System (INIS)

    Most discussion of refrigerant impacts on the environment has focused on protection of stratospheric ozone. The now-familiar Montreal Protocol, as revised last November at a meeting in Copenhagen, provides a clear mandate for transition to alternatives that do not deplete the earth's ozone layer. Coupled with reduction in refrigerant emissions, substitution of fluids with low or zero ozone-depletion potential (ODP) minimize or, for the latter, eliminate damage to the ozone layer. With retirement of the chlorofluorocarbon (CFC) refrigerants that once dominated in chillers for air conditioning systems, including r-11, R-12, R-113, R-114, and R-500 (which contains R-12), questions surface on other environmental concerns for the alternatives. The direct effect (chemical action as a greenhouse gas) alone however, is misleading. The thermodynamic properties of a refrigerant limit the efficiency that can be attained in a heat pump or refrigeration machine. Since the efficiency governs the amount of power required for a specific thermal load, the selection refrigerants also impacts the greenhouse gases, most notably carbon dioxide, released in supplying the required power. The warming stemming from combustion emissions to provide power is referred to as the indirect, or energy-related, effect. Atmospheric scientists use the term indirect effect to refer to the impact of greenhouse gases produced in the atmosphere by chemical reactions with an emission. The effect of this secondary chemistry is of much lesser magnitude and is not further discussed in this article

  20. Atmospheric Chemistry of CF3CF=CH2: Reactions With Cl Atoms, OH Radicals and Ozone

    Science.gov (United States)

    Sulbaek Andersen, M. P.; Javadi, M. S.; Nielsen, O. J.; Hurley, M. D.; Wallington, T. J.; Singh, R.

    2006-12-01

    The detrimental effects of chlorine chemistry on stratospheric ozone levels are well established. Consequently, there has been a concerted international effort to find replacements for chlorofluorocarbons (CFCs) used previously as electronic equipment cleaners, heat transfer agents, refrigerants, and carrier fluids for lubricant deposition. The replacements for CFCs, hydrofluorocarbons (HFCs) and hydrofluorochlorocarbons (HCFCs), have found widespread industrial use over the past decade. Unsaturated fluorinated hydrocarbons are a new class of compounds which have been developed to replace CFCs and HFCs in air condition units. Prior to any large-scale industrial use an assessment of the atmospheric chemistry, and hence environmental impact, of these compounds is needed. To address this need the atmospheric chemistry of CF3CF=CH2 was investigated. Smog chamber/FTIR techniques were used to determine the following properties for this compound: (i) kinetics of reactions with chlorine atoms (ii) kinetics of reactions with hydroxyl radicals (iii) kinetics of reactions with ozone, (iv) atmospheric lifetimes, (v) atmospheric degradation mechanism, and (vi) global warming potentials. The results are discussed with regard to the environmental impact of CF3CF=CH2 and the atmospheric chemistry of unsaturated fluorinated hydrocarbons.

  1. Early trends in the global tropospheric abundance of hydrochlorofluorocarbon-141b and 142b

    Science.gov (United States)

    Montzka, S. A.; Myers, R. C.; Butler, J. H.; Elkins, J. W.

    1994-11-01

    Hydrochlorofluorocarbons (HCFCs) are rapidly replacing chlorofluorocarbons (CFCs) as foam-blowing agents, solvents, and refrigerants. These substitutes, however, still contain chlorine and have the potential to deplete stratospheric ozone. Although the ozone destruction capacity of HCFCs is believed to be significantly less than that for CFCs, concern over unrestricted chlorine input to the atmosphere from HCFC use has prompted proposals for future limits on production. Here we report the first global time-series for mixing ratios of HCFC-141b (1,1-dichloro-1-fluoroethane) and HCFC-142b (1-chloro-1,1-difluoroethane) in air collected at seven remote sampling stations. Global mean mixing ratios in mid-1993 were 0.7 parts per 1012 (ppt) for HCFC-141b and 4.3 ppt for HCFC-142b. The global atmospheric abundance of HCFC-141b increased by 0.9 ppt, or a factor of ˜3, in 1993. Global abundance of HCFC-142b increased by 1.1 ppt yr-1 during 1992-1993. The results suggest that HCFCs are currently used extensively for replacing CFCs in selected applications. Furthermore, measured levels are significantly higher than expected based on available emission estimates and consumption predictions.

  2. CFCs, their replacements, and the ozone layer.

    Science.gov (United States)

    Noakes, T J

    1995-01-01

    Chlorofluorocarbons (CFCs) have become widely used in a variety of applications, ranging from aerosols to refrigeration, through their unique combination of the properties of nonflammability and general inertness. However, their chemical stability, which makes CFCs relatively safe and non-toxic, is also responsible for their potential to damage the environment. From 1974 opinion developed that CFCs might indirectly affect the stratospheric 'ozone layer' through their ability to transport halogens, particularly chlorine, to this level. By the mid 1980s a consensus emerged that atmospheric CFCs could contribute significantly to ozone depletion and an annual thinning (a 'hole') in the ozone layer over the Antarctic was reported. Some of the atmospheric chemistry which is believed to occur, and some of the measurements made on the ozone 'layer' are reviewed together with the environmental regulatory actions that have been taken. These are leading to a controlled rapid phase out of a number of industrial chemicals, including CFCs. The pharmaceutical industry uses significant quantities of CFCs as propellants in metered dose inhalers (MDIs). Two suitable alternative molecules, the hydrofluoroalkanes (HFAs) HFA134a and HFA227, which have the required properties but are not ozone depleting, are introduced. PMID:10150493

  3. Emission patterns and spatiotemporal variations of halocarbons in the Pearl River Delta region, southern China

    Science.gov (United States)

    Zhang, Y. L.; Guo, H.; Wang, X. M.; Simpson, I. J.; Barletta, B.; Blake, D. R.; Meinardi, S.; Rowland, F. S.; Cheng, H. R.; Saunders, S. M.; Lam, S. H. M.

    2010-08-01

    On 8 selected days between 25 October and 1 December 2007, 198 whole air samples were simultaneously collected at two sites in the greater Pearl River Delta (PRD), namely, Wan Qing Sha (WQS) in inland PRD and Tung Chung (TC) in Hong Kong, for the evaluation of halocarbons including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and other chlorinated compounds. The mean mixing ratios of CFC-12, CH3CCl3, CH3Br, C2HCl3, and C2Cl4 at WQS were much higher than those at TC (p refrigeration in 2007 were 1.4-2.0 times those in 2001-2002, and the use of HCFC-22 has significantly increased in these years while the use of C2HCl3 and C2Cl4 in the electronics industry showed a remarkable reduction. By comparing the halocarbon data collected in this study with those observed by other research teams in recent years, we found that the levels of CFCs have declined since 2001, while their substitute HCFC-22 has increased in emissions in recent years, especially in Hong Kong. The annual trends are consistent with the implementation of the Montreal Protocol. The results obtained in this study provide useful information to local government on effective control of halocarbon emissions in this region.

  4. Organized crime impact study highlights

    Energy Technology Data Exchange (ETDEWEB)

    Porteous, S.D.

    1998-10-01

    A study was conducted to address the issue of how organized crime impacts on Canadians and their communities both socially and economically. As far as environmental crime is concerned, three main areas of concern have been identified: (1) illicit trade in ozone depleting substances, (2) illicit hazardous waste treatment, and (3) disposal of illicit trade in endangered species. To gauge the magnitude of organized crime activity, the market value of worldwide illegal trafficking in illicit drugs was estimated to be as high as $100 billion worldwide (between $1.4 to 4 billion in Canada). It is suspected that Canada supplies a substantial portion of the U.S. black market in chlorofluorocarbons with most of the rest being supplied from Mexico. Another area of concern involves the disposal of hazardous wastes. Canada produces approximately 5.9 million tonnes of hazardous waste annually. Of these, 3.2 million tonnes are sent to off-site disposal facilities for specialized treatment and recycling. The treatment of hazardous waste is a very profitable business, hence vulnerable to fraudulent practices engaged in by organized crime groups. Environmental implications of this and other environmental crimes, as well as their economic, commercial, health and safety impact were examined. Other areas of organized crime activity in Canada (drugs, economic crimes, migrant trafficking, counterfeit products, motor vehicle theft, money laundering) were also part of the study.

  5. Groundwater environmental tracer data collected from the Chicot, Evangeline, and Jasper aquifers in Montgomery County and adjacent counties, Texas, 2008

    Science.gov (United States)

    Oden, Timothy D.

    2011-01-01

    The Gulf Coast aquifer system is the primary water supply for Montgomery County in southeastern Texas, including part of the Houston metropolitan area and the cities of Magnolia, Conroe, and The Woodlands Township, Texas. The U.S. Geological Survey, in cooperation with the Lone Star Groundwater Conservation District, collected environmental tracer data in the Gulf Coast aquifer system, primarily in Montgomery County. Forty existing groundwater wells screened in the Gulf Coast aquifer system were selected for sampling in Montgomery County (38 wells), Waller County (1 well), and Walker County (1 well). Groundwater-quality samples, physicochemical properties, and water-level data were collected once from each of the 40 wells during March-September 2008. Groundwater-quality samples were analyzed for dissolved gases and the environmental tracers sulfur hexafluoride, chlorofluorocarbons, tritium, helium-4, and helium-3/tritium. Water samples were collected and processed onsite using methods designed to minimize changes to the water-sample chemistry or contamination from the atmosphere. Replicate samples for quality assurance and quality control were collected with each environmental sample. Well-construction information and environmental tracer data for March-September 2008 are presented.

  6. A decade of discontinuity.

    Science.gov (United States)

    Brown, L R

    1993-01-01

    Usual trends in the world have changed direction in the 1990s. We do not yet fully know the consequences of these altered trends. As population continues to grow, basic agricultural and industrial production falls (e.g., 1%/year decline in grain production and 0.6%/year decline in oil production). Moreover, world economic growth has fallen .8% annually in the early 1990s. It is feared that these shifts are not short term as were the instabilities generated during the 1973 increase in oil prices. The shifts in the 1990s are not limited to several national political leaders (e.g., OPEC), but are a result of the collision between swelling human numbers and their needs and the limitations of the earth's natural systems on the other. These limitations include the capacity of seas to produce seafood, of grasslands to yield mutton and beef, of the hydrological cycle to generate fresh water, of crops to use fertilizer, of the atmosphere to absorb carbon dioxide and chlorofluorocarbons, and of people to inhale polluted air, and of forests to resist acid rain. These constraints are forcing the realization that each nation must reduce consumption of the earth's natural resources and implement a population policy. The challenge is for social institutions to quickly check and stabilize population growth without infringing in human rights.

  7. The chemical industry - friend to the environment?

    International Nuclear Information System (INIS)

    ''The Chemical Industry - Friend to the Environment?'' was a symposium organised by the North East Region committee of the Industrial Division of the Royal Society of Chemistry. This volume contains typescripts from all the lectures given at the symposium. The general public appreciate the material comforts the Chemical Industry provides, for example textiles, ceramics, steel, speciality chemicals, drugs, prosthetics etc. However, for many their comfort is spoiled by the chemical poisoning of the environment through slag heaps, beaches and countryside littered with non-biodegradable unsightly plastic containers, poor air quality through NOx, CO2 and chlorofluorocarbon emissions, and of course, nuclear waste. The occasional spillage of hazardous chemicals through road, rail and sea accidents do nothing to improve the Industry's image. The majority of these topics were discussed, though no one presumed to know how to remove the problems entirely but many suggestions were put forward as to how this might be achieved. Of the 13 papers presented three were specifically concerned with recycling of plastics, 9 with the environmental impacts of chemicals and one, which is indexed separately, was concerned with radioactive discharges into the environment from the Sellafield reprocessing plant. (Author)

  8. New ecology, global change, and forest politics

    International Nuclear Information System (INIS)

    Ecosystems constantly change. Some changes are caused by natural conditions that evolve at a very slow pace including climate change, species evolution and migration, and soil formation. Forests don't always respond to gradual changes in gradual ways, though gradual change may be hidden for years within the normal variation in the ecosystem. The industrial age has resulted in a rapid and continuing buildup of atmospheric gases such as carbon dioxide, methane, and chlorofluorocarbons which trap heat in the greenhouse effect. Industrial processes also emit oxides of nitrogen and sulfur that change atmospheric chemistry and alter the nutrient input into ecosystems. Natural forests face a hard time adjusting to a rate of climatic change that is 3 to 10 times faster than species can migrate and that increases the occurrence of major windstorms. In the forest ecosystem where trees are removed or destroyed under rapid climatic change, conditions may not return to their original state, even if we try to restore it. When the ecosystem changes faster than the bureaucracy of the management agency, a serious problem exists. New understandings of ecology and global change may force new ways of thinking in these situations

  9. Economics of "essential use exemptions" for metered-dose inhalers under the Montreal Protocol.

    Science.gov (United States)

    DeCanio, Stephen J; Norman, Catherine S

    2007-10-01

    The Montreal Protocol on Substances that Deplete the Ozone Layer has led to rapid reductions in the use of ozone-depleting substances worldwide. However, the Protocol provides for "essential use exemptions" (EUEs) if there are no "technically and economically feasible" alternatives. An application that might qualify as an "essential use" is CFC-powered medical metered-dose inhalers (MDIs) for the treatment of asthma and chronic obstructive pulmonary disease (COPD), and the US and other nations have applied for exemptions in this case. One concern is that exemptions are necessary to ensure access to medications for low-income uninsureds. We examine the consequences of granting or withholding such exemptions, and conclude that government policies and private-sector programs are available that make it economically feasible to phase out chlorofluorocarbons (CFCs) in this application, thereby furthering the global public health objectives of the Montreal Protocol without compromising the treatment of patients who currently receive medication by means of MDIs. PMID:16982135

  10. EXERGETIC PERFORMANCE OF A DOMESTIC REFRIGERATOR USING R12 AND ITS ALTERNATIVE REFRIGERANTS

    Directory of Open Access Journals (Sweden)

    BUKOLA O. BOLAJI

    2010-12-01

    Full Text Available Production and use of R12 and other chlorofluorocarbon refrigerants will be prohibited completely all over the world in the year 2010 due to their harmful effects on the earth’s protective ozone layer. Therefore, in this study, the exergetic performance of a domestic refrigerator using two environment-friendly refrigerants (R134a and R152a was investigated and compared with the performance of the system when R12 (an ozone depleting refrigerant was used. The effects of evaporator temperature on the coefficient of performance (COP, exergy flow destruction, exergetic efficiency and efficiency defect in the four major components of the cycle for R12, R134a and R152a were experimentally investigated. The results obtained showed that the average COP of R152a was very close to that of R12 with only 1.4% reduction, while 18.2% reduction was obtained for R134a in comparison with that of R12. The highest average exergetic efficiency of the system (41.5% was obtained using R152a at evaporator temperature of -3.0oC. The overall efficiency defect in the refrigeration cycle working with R152a is consistently better (lower than those of R12 and R134a. Generally, R152a performed better than R134a in terms of COP, exergetic efficiency and efficiency defect as R12 substitute in domestic refrigeration system.

  11. Numerical optimization of a transcritical CO2/propylene cascaded refrigeration-heat pump system with economizer in HT cycle

    Indian Academy of Sciences (India)

    Alok Manas Dubey; Suresh Kumar; Ghanshyam Das Agrawal

    2015-04-01

    Use of organic refrigerants such as Hydrochlorofluorocarbons and Chlorofluorocarbons have been criticized for their adverse impact on the Earth's protective ozone layer and for their significant global warming potential (GWP). CO2 has been receiving great concern as an alternative refrigerant. Cascade refrigeration systems employing CO2 are used for low temperature applications. Being a low critical temperature fluid CO2 transcritical cascade systems offer low COP for a given application. Parallel compression economization is one of the promising cycle modifications to improve the COP of transcritical CO2 cascaded systems. In this paper, transcritical CO2/propylene cascade system with parallel compression economization in the HT cycle has been analysed for cooling/heating applications. An enhancement in COP of 9% has been predicted. Thermodynamic analysis on R744-R1270 cascade refrigeration system has been performed to determine the optimal value of the various design parameters of the system. The design parameters included are: gas cooler outlet temperature and intermediate temperature in the high temperature circuit and evaporator temperature and temperature difference in the cascade condenser in the low temperature circuit.

  12. Hydrochemical and isotope study of Lake Titicaca

    International Nuclear Information System (INIS)

    The chemical and isotopic compositions of Lake Titicaca and its inflow waters (precipitation, tributaries, groundwater) were determined with the aim of establishing the lake chemical and isotope balance. The three main regions of the lake, i.e. the Lago Mayor, the eastern and the western basins of Lago Menor, connected in cascade, show significant chemical and isotopic differences. Chloride and sodium balance indicates that an average of about 92% of the inflow water evaporates, and the remaining 8 % is lost through Rio Desaguadero and infiltration. The balance of each basin is also obtained, including the inter-basin fluxes. The stable isotope balance in not possible because no data are available on the mean atmospheric vapour isotopic composition. However, this was tentatively computed using the fluxes obtained from chemistry. The vapour δ-values are slightly more negative than those of rainfall. Tritium, noble gases and chloro-fluoro-carbons in vertical profiles show that the lake is vertically well mixed and there is no water segregation at depth. (author)

  13. Inhaled Drug Delivery: A Practical Guide to Prescribing Inhaler Devices

    Directory of Open Access Journals (Sweden)

    Pierre Ernst

    1998-01-01

    Full Text Available Direct delivery of medication to the target organ results in a high ratio of local to systemic bioavailability and has made aerosol delivery of respiratory medication the route of choice for the treatment of obstructive lung diseases. The most commonly prescribed device is the pressurized metered dose inhaler (pMDI; its major drawback is the requirement that inspiration and actuation of the device be well coordinated. Other requirements for effective drug delivery include an optimal inspiratory flow, a full inspiration from functional residual capacity and a breath hold of at least 6 s. Available pMDIs are to be gradually phased out due to their use of atmospheric ozone-depleting chlorofluorocarbons (CFCs as propellants. Newer pMDI devices using non-CFC propellants are available; preliminary experience suggests these devices greatly increase systemic bioavailability of inhaled corticosteroids. The newer multidose dry powder inhalation devices (DPIs are breath actuated, thus facilitating coordination with inspiration, and contain fewer ingredients. Furthermore, drug delivery is adequate even at low inspired flows, making their use appropriate in almost all situations. Equivalence of dosing among different devices for inhaled corticosteroids will remain imprecise, requiring the physician to adjust the dose of medication to the lowest dose that provides adequate control of asthma. Asthma education will be needed to instruct patients on the effective use of the numerous inhalation devices available.

  14. Effect of Bearing Cleaning on Long Term Bearing Life

    Science.gov (United States)

    Jett, Tim; Thom, R. L.

    1999-01-01

    For many years chlorofluorocarbon (CFC) based solvents, such as CFC-113 and 1,1,1, trichloroethane (TCA), were used as bearing cleaning solvents for space mechanism bearings. The 1995 ban on the production of ozone depleting chemicals (ODC) such as CFCs caused a change requiring the use of ODC-free cleaners for precision bearing cleaning. With this change the question arises; what effect if any do these new cleaners have on long term bearing life? The purpose of this study was to evaluate this effect. A one year test using 60 small electrical motors (two bearings per motor) was conducted in a high vacuum environment (2.0 x 10(exp -6) torr) at a temperature of 90 C. Prior to testing the bearings were cleaned with one of four cleaners. These cleaners included two aqueous based cleaners, a CFC based cleaner and supercritical carbon dioxide. Three space compatible greases were tested. After testing, the mass of each lubricated bearing was measured both pre and post test. Along with mass loss measurements a profilometer trace of each bearing was taken to measure post test wear of the bearings. In addition, the bearings were visually examined and analyzed using an optical microscope.

  15. Hybrid system: Heat pump-solar air dryer for grains; Sistema hibrido: bomba de calor - calentador solar de aire para el secado de productos agricolas

    Energy Technology Data Exchange (ETDEWEB)

    Soto Gomez, Willfredo [Instituto Tecnologico de Tijuana, Tijuana (Mexico); Ortega Herrera, Jose Angel [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)

    2000-07-01

    Design, building, operation and evaluation energy wise of a hybrid experimental type, with heat pump, that uses no chloride, does not destroy the ozone layer. It is solar air dryer for grains. In this research we dry rice. It has tree systems: 1.- A mechanical compression heat pump, 2.- An air solar heater, and 3.- An agriculture products dryer. The drying capacity is 20 pounds of grain /day, with a median daily solar radiation. The costs is approximately U.S. $ 6 000.00. The heat pump used 22 refrigerant first, and now works with refrigerant SUVA 9000. This refrigerant will be available this year in the I.S., it is one of the ecological class that substitutes the chlorofluorocarbonates. [Spanish] Se disena, construye, opera, y evalua energeticamente, un sistema hibrido tipo experimental, con bomba de calor que utiliza refrigerante que no contiene cloro, y no destruye la capa de ozono y un calentador solar de aire, para secar granos. En este trabajo secamos arroz. Se compone de tres sistemas: 1.- Bomba de calor por compresion mecanica, 2.- Calentador solar de aire, 3.- Secador de productos agricolas. La capacidad de secado es de 10 Kilos de granos/dia promedio. Tiene un costo aproximado de $ 60 000. La bomba de calor utiliza refrigerante 22 en una primera generacion, y actualmente opera con un refrigerante SUVA 9000, en una segunda generacion, este refrigerante se comercializara en este ano, en la Union Americana, pertenece a la familia de los llamados refrigerantes ecologicos, sustitutos de los clorofluorocarbonados.

  16. Balloonborne in situ gas chromatograph for measurements in the troposphere and stratosphere

    Science.gov (United States)

    Moore, F. L.; Elkins, J. W.; Ray, E. A.; Dutton, G. S.; Dunn, R. E.; Fahey, D. W.; McLaughlin, R. J.; Thompson, T. L.; Romashkin, P. A.; Hurst, D. F.; Wamsley, P. R.

    2003-03-01

    An in situ gas chromatograph (GC) instrument on a balloonborne package is described in detail and data from seven science deployments are presented. This instrument, the Lightweight Airborne Chromatograph Experiment (LACE), operates on the Observations of the Middle Stratosphere (OMS) in situ gondola and has taken data from the upper troposphere to near 32 km with a vertical resolution of better than 300 m. LACE chromatography has been developed to measure halon-1211, the chlorofluorocarbons (CFC-11, CFC-113, CFC-12), nitrous oxide (N2O), and sulfur hexafluoride (SF6) every 70 s and methyl chloroform (CH3CCl3), carbon tetrachloride (CCl4), hydrogen (H2), methane (CH4), and carbon monoxide (CO) every 140 s. In the introduction we present scientific motivation for choosing this suite of molecules and for the use of faster sample rates resulting in unprecedented vertical resolution from an in situ GC. Results from an intercomparison with the Airborne Chromatograph for Atmospheric Trace Species (ACATS-IV) instrument are shown to quantitatively connect this LACE data set to the complementary data set generated on board the NASA ER-2 aircraft.

  17. Overview of the use of refrigerating fluids in thermodynamical machines; Panorama de l`utilisation des fluides frigorigenes dans les machines thermodynamiques

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, J. [Syrec SA (France)

    1996-12-31

    The R-22 refrigerant has been used as a substitute of chlorofluorocarbons in refrigerating machineries but its use will become prohibited very soon. This paper raises the problem of its replacement by other HFC or natural fluids. The problem of natural fluids like ammonia or propane concerns their toxicity, flammability and explosion risk. If a regulation about the greenhouse effect is defined, the performance of the installation will be the decisive parameter for the choice of a refrigerant. R-22 fluid has multiple applications from air-conditioning systems to freezing tunnels and the most suitable substitutes will be different from one application to the other. The different criteria that influence the choice of a refrigerating fluid are: the condensation pressure, the delivery temperature, the compressor volume efficiency, the volume refrigerating power, the coefficient of performance, the variation of vaporization temperature, the global greenhouse effect, the toxicity, flammability and explosive character. A comparison between several fluids has been performed with a single-stage airtight compressor of 10 m{sup 3}/h, at a 40 deg. C constant condensation temperature, a 5 deg. C overheating and a 3 deg. C under-cooling. (J.S.) 6 refs.

  18. Replacement of CFCs in thermodynamical systems; Remplacement des CFC dans les systemes thermodynamiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    Some chlorofluorocarbons (CFCs) are well-adapted to coldness production by vapour compression and thus are widely used in the storage of agriculture-food products from the production to the domestic consumer but also in air-conditioning systems and heat pumps. Atmospheric impacts of the use of CFCs (`ozone hole`) led the international community to adopt remedial measures which aim to prohibit the production of CFCs. These constraints led the users of refrigerating fluids to use substitution fluids and to develop new techniques of energy recovery and heat/coldness production. This workshop takes stock of this situation and of the problems encountered by the various actors involved in the replacement of CFCs in thermodynamical systems: evolutions of regulation, point of view of refrigerating fluid producers and of compressors and heat exchangers manufacturers, research studies on substitution fluids, recovery of CFCs and other refrigerating fluids, revival in the use of natural fluids (like ammonia), and use of new thermodynamical systems like compression/absorption (water/ammonia) cycles. (J.S.)

  19. Greenhouse impact of CH{sub 4}, N{sub 2}O and CFC emissions in Finland and its control potential

    Energy Technology Data Exchange (ETDEWEB)

    Pipatti, R.; Savolainen, I.; Sinisalo, J. [VTT Energy, Espoo (Finland)

    1995-12-31

    Methane (CH{sub 4}), nitrous oxide (N{sub 2}O) and chlorofluorocarbon (CFC) emissions contribute considerably to the anthropogenic enhancement of Earth`s greenhouse effect. The limitation of atmospheric concentrations of CH{sub 4} and N{sub 2}O is considered important also in the Climate Convention. Chlorine released from the CFCs in the stratosphere destroys ozone (O{sub 3}) and the emissions are therefore regulated with the Montreal Protocol. The greenhouse impact of CFCs might be, at least to some extent, compensated by the depletion of O{sub 3} which is also a greenhouse gas. The objective of the presentation is to assess the role of anthropogenic CH{sub 4}, N{sub 2}O, and CFC emissions in the total direct greenhouse impact due to human activities in Finland. The emission estimates for the gases are presented, as well as scenarios for emission history, future development and control potential. The greenhouse impact of the gases is compared with that of carbon dioxide (CO{sub 2}) emissions in Finland. (author)

  20. UV-VIS Spectroscopy Applied to Stratospheric Chemistry, Methods and Results

    Energy Technology Data Exchange (ETDEWEB)

    Karlsen, K.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Numerous observations and modeling have shown with a very high degree of certainty that the man-made emissions of chlorofluorocarbons (CFC) and halons are responsible for the Antarctica ozone hole. It is also evident that the ozone layer of the Northern Hemisphere has suffered a certain decline over the last 10-15 years, possibly because of CFC and halons. 20-30% of the observed reduction is ascribed to coupled chlorine and bromine chemistry via a catalytic cycle resulting in the net conversion of 2O{sub 3} to 3O{sub 2}. But the details are not fully understood. The author plans to assemble a UV-VIS spectrometer for measuring the species OClO and BrO and to compare and discuss measured diurnal variations of OClO and BrO with model calculations. The use of Differential Optical Absorption Spectroscopy (DOAS) is discussed and some results from late 1995 presented. 6 refs., 2 figs.

  1. CFC-11 destruction by microwave torch generated atmospheric-pressure nitrogen discharge

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, Mariusz; Mizeraczyk, Jerzy; Zakrzewski, Zenon [Centre for Plasma and Laser Engineering, Institute of Fluid Flow Machinery, Polish Academy of Sciences, Gdansk (Poland); Ohkubo, Toshikazu [Department of Electrical and Electronic Engineering, Oita University, Oita (Japan); Chang Jenshih [Department of Engineering Physics, McMaster University, Hamilton, ON (Canada)

    2002-09-21

    A novel plasma method and its application for destruction of Freons using a moderate-power (several hundred watts) microwave torch discharge (MTD) in atmospheric-pressure flowing nitrogen are presented. The capability of the MTD to decompose Freons is demonstrated using a chlorofluorocarbon CCl{sub 3}F (Freon CFC-11) as an example. The gas flow rate and microwave power (2.45 GHz) delivered to the MTD were 1-3 litre min{sup -1} and 200-400 W, respectively. Concentration of the CFC-11 in the nitrogen was up to 50%. The results show that the decomposition efficiency of CFC-11 is up to 100% with the removal rate of several hundred g h{sup -1} and energy efficiency of about 1 kg kWh{sup -1}. This impressive performance, superior to that of other methods, is achieved without generating any significant unwanted by-products. As a result of this investigation, a relatively low-cost prototype system for Freon destruction based on a moderate-power MTD and a scrubber is proposed. (author)

  2. New challenges threatening the ozone layer

    Science.gov (United States)

    Abubakar, Babagana

    Since the beginning of the 1990's when the importation of fairly used Refrigerators, Airconditioners and propellants that can easily go broken containing chlorofluorocarbon substances that is capable of destroying the Ozone layer started in commercial quantity in Africa, the African refuse mountains began metamorphosing into mountains of dumped broken Refrigerators, Air-conditioners and Propellants which are collectively becoming a threat to the Ozone layer, because of the continuous discharging of the Chlorofluorocarbon gases by the refuse in to the atmosphere in each passing second.. Nobody can actually quantify the numbers of Refrigerators, Air-conditioners and Propellants imported and disposed in Africa over the last fifteen years, but the facts still remains that the numbers of metamorphosing mountains keeps on increasing in both size and numbers in each passing day. They have even become sources of raw materials for the local blacksmiths, children and refrigerators repairers who use parts of the dumped refrigerators, Air-conditioners and Propellants for their constructions, toys and repairs respectively. This explains the reason why despite the global efforts toward protecting the Ozone layer by the United Nations (UN), governments, International Organizations and climatologist among many others, but yet the hole in the Ozone layer keeps on expanding and the global temperature keeps on rising which resulted in the unusual phenomenon like the hurricanes "Katrina" and "Rita" the unusual floods in China, Thailand, Mozambique and to some extent even the Tsunami disaster that claims millions of lives in 2004.The Rapid rising in temperature of the Tropical world countries and increase in the cases of cancer patients among many other unusual happenings over the last eight years. It was in review of the above situation that this research work was conducted and came up with the under listed suggestions/Recommendations: 1. The UN should use its capacity to discourage

  3. Three-dimensional thermal aging and dimensional stability of cellular plastic insulation

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Youchen; Kokko, E. [VTT Building Technology, Espoo (Finland). Building Physics, Puilding Services and Fire Technology

    1996-12-31

    The requirement of producing environmental-friendly plastic foam results in the replacement of the traditional blowing agents, CFCs (chlorofluorocarbons), with zero ozone depletion potential (ODP) alternatives. The tool which is able to evaluate the quality of the new generation of plastic foams becomes practically important. A 3-dimensional (3-D) heat and mass (gases) transfer model with respect to rigid closed-cell cellular plastics has been carefully deduced and furnished based on our previous understanding of such problems. To solve the 3-D parabolic partial differential equations subject to the third type of boundary conditions, a modified alternative direction implicit (AD I) finite difference method was developed by using the natural laws. To predict the long-term dimensional stability of a plastic foam insulation in air, a simplified mechanical model has been presented. In addition, to closure the prediction of foam dimensional stability, we have deduced a general relationship between the elastic modulus (Young`s modulus) of a rigid closed-cell cellular plastic, E{sub f} and its density, {phi}{sub p}. In comparison to the published measurements and other two well-known E{sub f} - {phi}{sub p} models, it is found that our E{sub f} - up relationship gives better prediction and is valid over the entire rigid plastic foam density range. Thermal aging and average volume change of zero ODP foams with different facing will be addressed. In addition, the application of the model shows the effects of foam dimension and facing on its thermal aging and deformation. (orig.) (13 refs.)

  4. Groundwater-quality and quality-control data for two monitoring wells near Pavillion, Wyoming, April and May 2012

    Science.gov (United States)

    Wright, Peter R.; McMahon, Peter B.; Mueller, David K.; Clark, Melanie L.

    2012-01-01

    In June 2010, the U.S. Environmental Protection Agency installed two deep monitoring wells (MW01 and MW02) near Pavillion, Wyoming, to study groundwater quality. During April and May 2012, the U.S Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, collected groundwater-quality data and quality-control data from monitoring well MW01 and, following well redevelopment, quality-control data for monitoring well MW02. Two groundwater-quality samples were collected from well MW01—one sample was collected after purging about 1.5 borehole volumes, and a second sample was collected after purging 3 borehole volumes. Both samples were collected and processed using methods designed to minimize atmospheric contamination or changes to water chemistry. Groundwater-quality samples were analyzed for field water-quality properties (water temperature, pH, specific conductance, dissolved oxygen, oxidation potential); inorganic constituents including naturally occurring radioactive compounds (radon, radium-226 and radium-228); organic constituents; dissolved gasses; stable isotopes of methane, water, and dissolved inorganic carbon; and environmental tracers (carbon-14, chlorofluorocarbons, sulfur hexafluoride, tritium, helium, neon, argon, krypton, xenon, and the ratio of helium-3 to helium-4). Quality-control sample results associated with well MW01 were evaluated to determine the extent to which environmental sample analytical results were affected by bias and to evaluate the variability inherent to sample collection and laboratory analyses. Field documentation, environmental data, and quality-control data for activities that occurred at the two monitoring wells during April and May 2012 are presented.

  5. Protecting the ozone layer.

    Science.gov (United States)

    Munasinghe, M; King, K

    1992-06-01

    Stratospheric ozone layer depletion has been recognized as a problem by the Vienna Convention for the Protection of the Ozone Layer and the 1987 Montreal Protocol (MP). The ozone layer shields the earth from harmful ultraviolet radiation (UV-B), which is more pronounced at the poles and around the equator. Industrialized countries have contributed significantly to the problem by releasing chlorofluorocarbons (CFCs) and halons into the atmosphere. The effect of these chemicals, which were known for their inertness, nonflammability, and nontoxicity, was discovered in 1874. Action to deal with the effects of CFCs and halons was initiated in 1985 in a 49-nation UN meeting. 21 nations signed a protocol limiting ozone depleting substances (ODS): CFCs and halons. Schedules were set based on each country's use in 1986; the target phaseout was set for the year 2000. The MP restricts trade in ODSs and weights the impact of substances to reflect the extent of damage; i.e., halons are 10 times more damaging than CFCs. ODS requirements for developing countries were eased to accommodate scarce resources and the small fraction of ODS emissions. An Interim Multilateral Fund under the Montreal Protocol (IMFMP) was established to provide loans to finance the costs to developing countries in meeting global environmental requirements. The IMFMP is administered by the World Bank, the UN Environmental Program, and the UN Development Program. Financing is available to eligible countries who use .3 kg of ODS/person/year. Rapid phaseout in developed countries has occurred due to strong support from industry and a lower than expected cost. Although there are clear advantages to rapid phaseout, there were no incentives included in the MP for rapid phaseout. Some of the difficulties occur because the schedules set minimum targets at the lowest possible cost. Also, costs cannot be minimized by a country-specific and ODS-specific process. The ways to improve implementation in scheduling and

  6. Nitrate source indicators in ground water of the Scimitar Subdivision, Peters Creek area, Anchorage, Alaska

    Science.gov (United States)

    Wang, Bronwen; Strelakos, Pat M.; Jokela, Brett

    2000-01-01

    A combination of aqueous chemistry, isotopic measurement, and in situ tracers were used to study the possible nitrate sources, the factors contributing to the spatial distribution of nitrate, and possible septic system influence in the ground water in the Scimitar Subdivision, Municipality of Anchorage, Alaska. Two water types were distinguished on the basis of the major ion chemistry: (1) a calcium sodium carbonate water, which was associated with isotopically heavier boron and with chlorofluorocarbons (CFC's) that were in the range expected from equilibration with the atmosphere (group A water) and (2) a calcium magnesium carbonate water, which was associated with elevated nitrate, chloride, and magnesium concentrations, generally isotopically lighter boron, and CFC's concentrations that were generally in excess of that expected from equilibration with the atmosphere (group B water). Water from wells in group B had nitrate concentrations that were greater than 3 milligrams per liter, whereas those in group A had nitrate concentrations of 0.2 milligram per liter or less. Nitrate does not appear to be undergoing extensive transformation in the ground-water system and behaves as a conservative ion. The major ion chemistry trends and the presence of CFC's in excess of an atmospheric source for group B wells are consistent with waste-water influences. The spatial distribution of the nitrate among wells is likely due to the magnitude of this influence on any given well. Using an expanded data set composed of 16 wells sampled only for nitrate concentration, a significant difference in the static water level relative to bedrock was found. Well water samples with less than 1 milligram per liter nitrate had static water levels within the bedrock, whereas those samples with greater than 1 milligram per liter nitrate had static water levels near or above the top of the bedrock. This observation would be consistent with a conceptual model of a low-nitrate fractured bedrock

  7. UV and infrared absorption spectra, atmospheric lifetimes, and ozone depletion and global warming potentials for CCl2FCCl2F (CFC-112), CCl3CClF2 (CFC-112a), CCl3CF3 (CFC-113a), and CCl2FCF3 (CFC-114a)

    Science.gov (United States)

    Davis, Maxine E.; Bernard, François; McGillen, Max R.; Fleming, Eric L.; Burkholder, James B.

    2016-07-01

    The potential impact of CCl2FCF3 (CFC-114a) and the recently observed CCl2FCCl2F (CFC-112), CCl3CClF2 (CFC-112a), and CCl3CF3 (CFC-113a) chlorofluorocarbons (CFCs) on stratospheric ozone and climate is presently not well characterized. In this study, the UV absorption spectra of these CFCs were measured between 192.5 and 235 nm over the temperature range 207-323 K. Precise parameterizations of the UV absorption spectra are presented. A 2-D atmospheric model was used to evaluate the CFC atmospheric loss processes, lifetimes, ozone depletion potentials (ODPs), and the associated uncertainty ranges in these metrics due to the kinetic and photochemical uncertainty. The CFCs are primarily removed in the stratosphere by short-wavelength UV photolysis with calculated global annually averaged steady-state lifetimes (years) of 63.6 (61.9-64.7), 51.5 (50.0-52.6), 55.4 (54.3-56.3), and 105.3 (102.9-107.4) for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. The range of lifetimes given in parentheses is due to the 2σ uncertainty in the UV absorption spectra and O(1D) rate coefficients included in the model calculations. The 2-D model was also used to calculate the CFC ozone depletion potentials (ODPs) with values of 0.98, 0.86, 0.73, and 0.72 obtained for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. Using the infrared absorption spectra and lifetimes determined in this work, the CFC global warming potentials (GWPs) were estimated to be 4260 (CFC-112), 3330 (CFC-112a), 3650 (CFC-113a), and 6510 (CFC-114a) for the 100-year time horizon.

  8. Groundwater Quality, Age, and Probability of Contamination, Eagle River Watershed Valley-Fill Aquifer, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, L. Niel

    2009-01-01

    The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado. Ground- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.

  9. Recharge sources and residence times of groundwater as determined by geochemical tracers in the Mayfield Area, southwestern Idaho, 2011–12

    Science.gov (United States)

    Hopkins, Candice B.

    2013-01-01

    Parties proposing residential development in the area of Mayfield, Idaho are seeking a sustainable groundwater supply. During 2011–12, the U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, used geochemical tracers in the Mayfield area to evaluate sources of aquifer recharge and differences in groundwater residence time. Fourteen groundwater wells and one surface-water site were sampled for major ion chemistry, metals, stable isotopes, and age tracers; data collected from this study were used to evaluate the sources of groundwater recharge and groundwater residence times in the area. Major ion chemistry varied along a flow path between deeper wells, suggesting an upgradient source of dilute water, and a downgradient source of more concentrated water with the geochemical signature of the Idaho Batholith. Samples from shallow wells had elevated nutrient concentrations, a more positive oxygen-18 signature, and younger carbon-14 dates than deep wells, suggesting that recharge comes from young precipitation and surface-water infiltration. Samples from deep wells generally had higher concentrations of metals typical of geothermal waters, a more negative oxygen-18 signature, and older carbon-14 values than samples from shallow wells, suggesting that recharge comes from both infiltration of meteoric water and another source. The chemistry of groundwater sampled from deep wells is somewhat similar to the chemistry in geothermal waters, suggesting that geothermal water may be a source of recharge to this aquifer. Results of NETPATH mixing models suggest that geothermal water composes 1–23 percent of water in deep wells. Chlorofluorocarbons were detected in every sample, which indicates that all groundwater samples contain at least a component of young recharge, and that groundwater is derived from multiple recharge sources. Conclusions from this study can be used to further refine conceptual hydrological models of the area.

  10. 2013 Update of NOAA's Annual Greenhouse Gas Index

    Science.gov (United States)

    Butler, James H.; Montzka, Stephen A.; Dlugokencky, Edward J.; Elkins, James W.; Masari, Kenneth A.; Schnell, Russell C.; Tans, Pieter P.

    2013-04-01

    Indexes are becoming increasingly important in communicating messages about climate change to a diverse public. Indexes exist for a number of climate-related phenomena including heat, precipitation, and extreme events. These help communicate complex phenomena to the public and, at times, policy makers, to aid in understanding or making decisions. Several years ago, NOAA introduced a unique index for expressing the influence of human-emitted, long-lived greenhouse gases in the atmosphere (DJ Hofmann et al., Tellus, 2006, S8B 614-619). Essentially a condensation and normalization of radiative forcing from long-lived gases, the NOAA Annual Greenhouse Gas Index (AGGI) was designed to enhance the connection between scientists and society by providing a standard that could be easily understood and followed. The index each year is calculated from high quality, long-term observations by NOAA's Global Monitoring Division, which includes real-time measurements extending over the past five decades, as well as published ice core record that go back to 1750. The AGGI is normalized to 1.00 in 1990, the Kyoto Climate Protocol baseline year. At the end of 2011, the AGGI was 1.30, indicating that global radiative forcing by long-lived greenhouse gases had increased 30% since 1990. During the 1980s CO2 accounted for about 50-60% of the annual increase in radiative forcing by long-lived greenhouse gases, whereas, since 2000, it has accounted for 85-90% of this increase each year. After nearly a decade of virtually level concentrations in the atmosphere, methane (CH4) increased measurably over the past 2-3 years, as did its contribution to radiative forcing. In addition to presenting the AGGI for 2012, increases in radiative forcing will be evaluated and discussed with respect to the contributions from CO2, CH4, nitrous oxide (N2O), chlorofluorocarbons (CFCs), and other emerging greenhouse gases.

  11. What we learn from updates of NOAA's Annual Greenhouse Gas Index (AGGI)

    Science.gov (United States)

    Butler, James H.; Montzka, Stephen A.; Dlugokencky, Edward; Elkins, James W.; Masarie, Kenneth; Schnell, Russell C.; Tans, Pieter; Dutton, Geoff; Miller, Ben R.

    2014-05-01

    Several years ago, NOAA introduced a unique index for expressing the influence of human-emitted, long-lived greenhouse gases in the atmosphere (D.J. Hofmann et al., Tellus, 2006, S8B, 614-619). Being a condensation and normalization of radiative forcing from long-lived gases, the NOAA Annual Greenhouse Gas Index (AGGI) was designed to enhance the connection between scientists and society by providing a standard that could be easily understood and followed. The index each year is calculated from high quality, long-term observations by NOAA's Global Monitoring Division, which includes real-time measurements extending over the past five decades, as well as published ice core records that go back to 1750. The AGGI is radiative forcing from these long-lived gases, normalized to 1.00 in 1990, the Kyoto Climate Protocol baseline year. For 2012, the AGGI was 1.32, indicating that global radiative forcing by long-lived greenhouse gases had increased 32% since 1990. During the 1980s CO2 accounted for about 50-60% of the annual increase in radiative forcing (and the AGGI) by long-lived greenhouse gases, whereas, since 2000, it has accounted for 80-90% of this increase each year. After nearly a decade of virtually level concentrations in the atmosphere, methane (CH4) has increased measurably over the past 6 years, as did its contribution to radiative forcing (and the AGGI). This year, in addition to updating the AGGI for 2013, increases in radiative forcing will be evaluated and discussed with respect to time-dependent changes in the contributions from CO2, CH4, nitrous oxide (N2O), chlorofluorocarbons (CFCs), and other emerging greenhouse gases.

  12. Consistency of cruise data of the CARINA database in the Atlantic sector of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    M. Hoppema

    2009-12-01

    Full Text Available Initially a North Atlantic project, the CARINA carbon synthesis was extended to include the Southern Ocean. Carbon and relevant hydrographic and geochemical ancillary data from cruises all across the Arctic Mediterranean Seas, Atlantic and Southern Ocean were released to the public and merged into a new database as part of the CARINA synthesis effort. Of a total of 188 cruises, 37 cruises are part of the Southern Ocean, including 11 from the Atlantic sector. The variables from all Southern Ocean cruises, including dissolved inorganic carbon (TCO2, total alkalinity, oxygen, nitrate, phosphate and silicate, were examined for cruise-to-cruise consistency in one collective effort. Seawater pH and chlorofluorocarbons (CFCs are also part of the database, but the pH quality control (QC is described in another Earth System Science Data publication, while the complexity of the Southern Ocean physics and biogeochemistry prevented a proper QC analysis of the CFCs. The area-specific procedures of quality control, including crossover analysis between stations and inversion analysis of all crossover data (i.e. secondary QC, are briefly described here for the Atlantic sector of the Southern Ocean. Data from an existing, quality controlled database (GLODAP were used as a reference for our computations – however, the reference data were included into the analysis without applying the recommended GLODAP adjustments so the corrections could be independently verified. The outcome of this effort is an internally consistent, high-quality carbon data set for all cruises, including the reference cruises. The suggested corrections by the inversion analysis were allowed to vary within a fixed envelope, thus accounting for natural variability. The percentage of cruises adjusted ranged from 31% (for nitrate to 54% (for phosphate depending on the variable.

  13. ICI bites demerger bullet, Zeneca guns for Brit-pounds 1.3-billion rights issue

    International Nuclear Information System (INIS)

    Any lingering doubts as to ICI's (London) intentions to follow through its demerger proposals were dispelled last week. The company will hive off its bioscience business into Zeneca Group plc, which will make a Brit-pounds 1.3-billion ($1.9 billion) rights issue in June 1993. Shareholders, whose approval for the historic move will be sought in late May, will receive one fully paid Zeneca share for each ICI share. Proceeds from the rights issue will be used to reduce Zeneca's indebtedness to ICI by about 70%. Acknowledging that ICI had 'spread the jam too thinly' during its expansion in the 1980s, chief executive Ronnie Hampel says the new ICI will be a cost-conscious, no-frills' organization and that businesses that failed to perform would be restructured or closed. He is 'not expecting any help from the economy' in 1993. Of ICI's remaining petrochemicals and plastics businesses, Hampel says that despite 'stringent measures to reduce the cost base hor-ellipsis it is clear they will not reach a return on capital that will justify reinvestment by ICI.' He does not see them as closure candidates but as 'businesses that will require further restructuring.' Hampel notes 'a dozen clearly identified areas for expansion,' including paints, catalysts, titanium dioxide, and chlorofluorocarbon replacements. Losses in materials, where substantial rationalization has failed to halt the slide, will be reduced on completion of the DuPont deal - expected by midyear. 'Further measures' would be necessary for the 'residual bit of advanced materials in the US,' he says

  14. Italian WEEE management system and treatment of end-of-life cooling and freezing equipments for CFCs removal.

    Science.gov (United States)

    Sansotera, M; Navarrini, W; Talaeemashhadi, S; Venturini, F

    2013-06-01

    This study presents and analyzes the data of the Italian system for take-back and recovery of waste electrical and electronic equipments (WEEEs) in the start-up period 2008-2010. The analysis was focused particularly on the data about the treatment of end-of-life cooling and freezing equipments. In fact, the wastes of cooling and freezing equipments have a high environmental impact. Indeed, in their compressor oil and insulation polyurethane (PU) foams chlorofluorocarbon (CFC) ozone-depleting gases are still present. In the period 2001-2004 Northern Italy resulted the main source in Europe of CFCs. The European Directive on WEEE management was enacted in 2002, but in Italy it was implemented by the legislative Decree in 2005 and it became operational in 2008. Actually, in 2008 the national WEEE Coordination Centre was founded in order to organize the WEEE pick-up process and to control collection, recovery and recycling targets. As a result, in 2010 the average WEEE collection per capita exceeded the threshold of more than 4 kg per inhabitant, as well as cooling and freezing appliances represented more than one fourth of the Italian WEEE collection stream. During the treatment of end-of-life cooling and freezing equipments, CFCs were recovered and disposed principally by burner methods. The analyses of defined specimens collected in the treatment facilities were standardized to reliably determine the amount of recovered CFCs. Samples of alkaline solid salt, alkaline saline solution, polyurethane matrix and compressor oil collected during the audit assessment procedure were analyzed and the results were discussed. In particular, the analysis of PU samples after the shredding and the warm pressing procedures measured a residual CFCs content around 500-1300 mg/kg of CFCs within the foam matrix. PMID:23566340

  15. Stratospheric ozone, global warming, and the principle of unintended consequences--an ongoing science and policy success story.

    Science.gov (United States)

    Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan

    2013-06-01

    In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric ozone layer that protects Earth from harmful ultraviolet radiation. In the decade after scientists documented the buildup and long lifetime of CFCs in the atmosphere; found the proof that CFCs chemically decomposed in the stratosphere and catalyzed the depletion of ozone; quantified the adverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed the Montreal Protocol. Today, 25 years after the Montreal Protocol was agreed, every United Nations state is a party (universal ratification of 196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have been phased out worldwide; and the stratospheric ozone layer is on its way to recovery by 2065. A growing coalition of nations supports using the Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous science and international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds of the ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agricultural production. Furthermore, because most, ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of the equivalent of 24-76 gigatons per year of carbon dioxide. This critical review describes the history of the science of stratospheric ozone depletion, summarizes the evolution of control measures and compliance under the Montreal Protocol and national legislation, presents a review of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustrates government-industry cooperation in continually improving the environmental performance of motor vehicle A/C. PMID

  16. Self-, N2-, O2-broadening coefficients and line parameters of HFC-32 for ν7 band and ground state transitions from infrared and microwave spectroscopy

    Science.gov (United States)

    Tasinato, Nicola; Turchetto, Arianna; Puzzarini, Cristina; Stoppa, Paolo; Pietropolli Charmet, Andrea; Giorgianni, Santi

    2014-09-01

    Hydrofluorocarbons have been used as replacement gases of chlorofluorocarbons, since the latter have been phased out by the Montreal Protocol due to their environmental hazardous ozone-depleting effects. This is also the case of difluoromethane (CH2F2, HFC-32), which nowadays is widely used in refrigerant mixtures together with CF3CH3, CF3CH2F, and CF3CHF2. Due to its commercial use, in the last years, the atmospheric concentration of HFC-32 has increased significantly. However, this molecule presents strong absorptions within the 8-12 μm atmospheric window, and hence it is a greenhouse gas which contributes to global warming. Although over the years several experimental and theoretical investigations dealt with the spectroscopic properties of CH2F2, up to now pressure broadening coefficients have never been determined. In the present work, the line-by-line parameters of CH2F2 are retrieved for either ground state or ν7 band transitions by means of microwave (MW) and infrared (IR) absorption spectroscopy, respectively. In particular, laboratory experiments are carried out on 9 pure rotational transitions of the ground state and 26 ro-vibrational transitions belonging to the ν7 band lying around 8.2 μm within the atmospheric region. Measurements are carried out at room temperature on self-perturbed CH2F2 as well as on CH2F2 perturbed by N2 and O2. The line shape analysis leads to the first determination of self-, N2-, O2-, and air-broadening coefficients, and also of line intensities (IR). Upon comparison, broadening coefficients of ground state transitions are larger than those of the ν7 band, and no clear dependence on the rotational quantum numbers can be reported. The obtained results represent basic information for the atmospheric modelling of this compound as well as for remote sensing applications.

  17. Detected CFCs: UV Absorption Spectra, Atmospheric Lifetimes, Global Warming and Ozone Depletion Potentials for CFC-112, CFC-112a, CFC-113a and CFC-114a

    Science.gov (United States)

    Bernard, F.; Davis, M. E.; McGillen, M.; Fleming, E. L.; Burkholder, J. B.

    2015-12-01

    Chlorofluorocarbons (CFCs) are ozone depleting substances (ODSs) and potent greenhouse gases. Measurements have observed CFC-112 (CFCl2CFCl2), CFC-112a (CF2ClCCl3), and CFC-113a (CCl3CF3) in the atmosphere (Laube et al., 2014). The current atmospheric abundances of CFC-112 and CFC-112a are ~0.4 and ~0.06 ppt, respectively, with decreasing abundance since 1995. In contrast, CFC-113a was found to show continuous growth over the past 50 years with a current atmospheric abundance of ~0.5 ppt. The major atmospheric removal process for these compounds is expected to be UV photolysis in the stratosphere. To date there is, however, no UV absorption spectra for these compounds available in the literature. To better determine the atmospheric lifetimes and environmental impact of these CFCs, laboratory measurements of the UV absorption spectra of CFC-112, CFC-112a, CFC-113a, and CFC-114a (Cl2FCF3) between 195 and 235 nm and over the temperature range 207 to 323 K were performed. Spectrum parametrizations were developed for use in atmospheric models. Atmospheric lifetimes and ozone depletion potentials (ODPs) were calculated using the Goddard Space Flight Center 2-D atmospheric chemistry model. Infrared absorption spectra of these compounds were also measured and used to calculate their global warming potentials. The results of the laboratory measurements and model calculations will be presented. J. C. Laube et al., Newly detected ozone-depleting substances in the atmosphere, Nature Geoscience, 7, 266-269, 2014

  18. Risk assesment of an urban aquifer based on environmental tracers

    Directory of Open Access Journals (Sweden)

    Branka Trček

    2013-06-01

    Full Text Available Groundwater from a Pleistocene sandy-gravel aquifer is a drinking water resource for the Union brewery, located nearthe centre of Ljubljana (Slovenia. A large part of the aquifer recharge area is highly urbanized, which represents a greatrisk for the groundwater quality assurance. The groundwater dating techniques were used to study the contaminationrisk of this drinking-water resource. The application of chlorofluorocarbons (CFCs, sulphur hexafluoride (SF6 andtritium-helium-3 (3H-3He age indicator was tested, as they haven’t been used in Slovene urban areas so far. The resultsreflect that the 3H-3He dating technique is the most suitable for a groundwater age determination in the study urbanaquifer, since SF6 and particularly CFCs concentrations could be affected by the local contaminations. They indicatedthat average groundwater residence times range from 10 to 30 years. Boreholes that are more distant from the Ši{enskihrib hill are more vulnerable to contamination due to flow of young groundwater from a direction of the main aquifer,which is exposed to the urban pollution. The presented results were supplemented with chemical investigations ofgroundwater organic pollutants. An unknown trace organic pollutant with a base ion mass-to-charge ratio 147 was putinto focus. Its identification based on chromatographic separation and a mass spectrometric detection with GC-MS,LC-MS and LC-TOF MS techniques. The newly detected trace organic pollutant in sampled groundwater representstogether with the 3H and 3He data a new technique to study the flow paths and contaminant transport in the urbanaquifer in both, the lateral and vertical directions.

  19. Use of chloroflurocarbons as internal standards for the measurement of atmospheric non-methane volatile organic compounds sampled onto solid adsorbent cartridges.

    Science.gov (United States)

    Karbiwnyk, Christine M; Mills, Craig S; Helmig, Detlev; Birks, John W

    2003-03-01

    Solid adsorbents have proven useful for determining the vertical profiles of volatile organic compounds (VOCs) using sampling platforms such as balloons, kites, and light aircraft, and those profiles provide valuable information about the sources, sinks, transformations, and transport of atmospheric VOCs. One of the largest contributions to error in VOC concentrations is the estimation of the volume of air sampled on the adsorbent cartridge. These errors arise from different sources, such as variations in pumping flow rates from changes in ambient temperature and pressure with altitude, and decrease in the sampling pump battery power. Another significant source for sampling rate variations are differences in the flow resistance of individual sampling cartridges. To improve the accuracy and precision of VOC measurements, the use of ambient chlorofluorocarbons (CFCs) as internal standards was investigated. A multibed solid adsorbent, AirToxic (Supelco), was chosen for its wide sampling range (C3-C12). Analysis was accomplished by thermal desorption and dual detection GC/FID/ECD, resulting in sensitive and selective detection of both VOCs and CFCs in the same sample. Long-lived chlorinated compounds (CFC-11, CFC-12, CFC-113, CCl4 and CH3CCl3) banned by the Montreal Protocol and subsequent amendments were studied for their ability to predict sample volumes using both ground-based and vertical profiling platforms through the boundary layer and free troposphere. Of these compounds, CFC-113 and CCl4 were found to yield the greatest accuracy and precision for sampling volume determination. Use of ambient CFC-113 and CCl4 as internal standards resulted in accuracy and precision of generally better than 10% for the prediction of sample volumes in ground-, balloon-, and aircraft-based measurements. Consequently, use of CFCs as reference compounds can yield a significant improvement of accuracy and precision for ambient VOC measurements in situations where accurate flow

  20. Atmospheric chemistry of some concepts for engineered intervention into large-scale pollution problems

    International Nuclear Information System (INIS)

    As the era of global change approaches, serious debate has begun on the merits of regional and global-scale atmospheric engineering enterprises to repair pollution damage. Post hoc mitigation schemes often prove to be inordinately expensive, and are sometimes dangerous. Here, chemical ramifications are discussed for three engineering concepts the authors are involved in assessing. Two of their projects regard global ozone depletion. It has been proposed that additions of small quantities of the light alkanes to the ozone hole could suppress massive springtime losses over Antarctica by scavenging chlorine atoms. A newly discovered heterogeneous reaction, however, implies that hydrogen atoms released during organic oxidation will activate the scavenged chlorine and more. Alkane injections could thus deepen the hole instead of plugging it. Ground based infrared laser multiple-photon dissociation has been suggested as a means for removing chlorofluorocarbons from the atmosphere before they can reach the ozone layer and cause depletions. The process would release chlorine atoms into the tropospheric system, and might lead to localized ozone production and smog-like plumes downwind of the laser assemblages. The third engineering proposal the authors are evaluating focuses on urban pollution. Reverse convection towers can generate electricity by channeling the cooling from evaporation of water droplets into controlled downdrafts. It has been noted that if the towers were constructed in cities, the falling drops within them would sweep out visibility-degrading particles. However, alterations in NOx could increase the intensity of midday ozone episodes. Their overall experience indicates that the direction and magnitude of potential chemical side effects of post hoc environmental engineering will be difficult to predict. 99 refs

  1. The Evolution of Pressurized Metered-Dose Inhalers from Early to Modern Devices.

    Science.gov (United States)

    Roche, Nicolas; Dekhuijzen, P N Richard

    2016-08-01

    Pressurized metered-dose inhalers (pMDIs) are sometimes viewed as old-fashioned and as having been superseded by dry powder inhalers (DPIs). Here, we review the technological advances that characterize modern pMDIs, and consider how they can influence the effectiveness of drug delivery for patients with asthma and chronic obstructive pulmonary disease. Compared with old chlorofluorocarbon (CFC)-based inhalers, many hydrofluoroalkane (HFA)-driven pMDIs have more favorable plume characteristics such as a reduced velocity and a higher fine particle fraction; together, these advances have resulted in the development of pMDIs with reduced oropharyngeal deposition and increased lung deposition. In addition, the plume from many HFA-pMDIs is warmer, which may facilitate their use by patients; moreover, devices are equipped with dose counters, which improves their reliability. As well as reviewing the technological advances of pMDIs, we also discuss the importance of individualizing inhaler therapies to each patient by accounting for their personal preferences and natural breathing patterns. Because pMDIs and DPIs differ considerably in their handling characteristics, matching the right inhaler to the right patient is key to ensuring effective therapy and good compliance. Finally, the majority of patients can be trained successfully in the correct use of their pMDI; training and regular monitoring of inhalation technique are essential prerequisites for effective therapy. While the 'ideal inhaler' may not exist, pMDIs are an effective device option suitable for many patients. pMDIs, together with other types of devices, offer opportunities for the effective individualization of treatments. PMID:26824873

  2. Conservation and fusion as solutions for the greenhouse or global warming effect

    International Nuclear Information System (INIS)

    The US and other countries are expected to spend trillion dollar sums for power plants in the next decades. Just in the coming decade, the US oil and natural gas production are expected to decline. The US does have abundant supplies of coal. But as has become apparent because of the effects of chlorofluorocarbons (CFC's) on ozone in the atmosphere, the effects of human activity on the earth's global environment has already reached an alarming level. A likely more dangerous prospect awaits as one contemplates the effects on the global climate due to rapid increase of heat trapping gases in the atmosphere. Half of this increase arises from energy activity, another quarter from industrial activity (almost entirely due to CFC's). The important and much emphasized effect of deforestation is only a 14% effect at present and agricultural activities contribute another 13%. For the US midwest, which dominates the world trade in basic cereals due to favorable climate and soil conditions, ''Murphy's Law of Applied Statistics'' would be sufficient to imply that any weather changes would lead to less favorable agricultural conditions. The effects of global agricultural failures coupled to increased energy costs could feed back into more rapid human economic activities that lead to accelerated climate changes. Losses are also expected along low lying coastal areas such as near the Indian Ocean, the coastal states, for example Florida, but also elsewhere. And there are other such nonlinear feedback factors which could accelerate the timescale of global warming. Since energy consumption in the US is some five times that of Japan, a rapid conservation program is a must, e.g. in more efficient electric lighting. But for the intermediate term, it can be argued that the US must simultaneously phase in fusion or other similar non-hydrocarbon-based energy technologies. Easily usable oil and natural gas should eventually be reserved for the petrochemical industries

  3. The greenhouse effect and global climate change

    International Nuclear Information System (INIS)

    The ongoing increase in the concentration of infrared-absorbing gases in the atmosphere is already causing and will continue to cause a growing unbalance in the radiation budget of the earth, and consequent warming of the lower atmosphere and earth surface. This climate phenomenon is the manifestation of the greenhouse or blanketing effect of absorbing gases (also known as ''greenhouse gases'') in the earth atmosphere. The main chemical species responsible for the build-up of the greenhouse effect are carbon dioxide, methane and chlorofluorocarbons (CFCs) or freons. Despite new regulatory efforts made by governments to slow down the emission of these gases, the combined atmospheric burden could be equivalent to doubling the pre-industrial concentration of carbon dioxide (2xCO2) by the middle of next century. The global warming of the earth surface would eventually reach about 4 deg. C if the 2xCO2 concentration then was maintained constant for a long period. As it is, the transient response of climate to an increasing greenhouse effect is delayed by 50 to 100 years. For this reason, we observe now a much smaller climate warming than would occur for climate equilibrium with the present atmospheric composition, i.e. 125% the pre-industrial concentration of CO2. Impacts of this phenomenon will range from disturbances of the existing hydrological regime of the planet to rise of the global mean sea-level. A warmer atmosphere means more rain but also faster evaporation: consequences in terms of the availability of water resources are unclear at temperate and high latitudes, but an aggravation of aridity in sub-tropical latitudes is probable. Sea-level rise may reach 50 cm by 2100. In general, the rate of climate warming when the climate system starts responding to the greenhouse effect could be 0.3 deg. C per decade, far exceeding the ability of natural ecosystems to adapt effectively to the change. (author). 5 refs, 2 figs

  4. Experimental characterization of the COndensation PArticle counting System for high altitude aircraft-borne application

    Directory of Open Access Journals (Sweden)

    R. Weigel

    2008-11-01

    Full Text Available This study aims at a detailed characterization of an ultra-fine aerosol particle counting system for operation on board the Russian high altitude research aircraft M-55 "Geophysica" (maximum ceiling of 21 km. The COndensation PArticle counting Systems (COPAS consists of an aerosol inlet and two dual-channel continuous flow Condensation Particle Counters (CPCs.

    The aerosol inlet, adapted for COPAS measurements on board the M-55 "Geophysica", is described concerning aspiration, transmission, and transport losses. The counting efficiencies of the CPCs using the chlorofluorocarbon FC-43 as the working fluid are studied experimentally at two pressure conditions, 300 hPa and 70 hPa. Three COPAS channels are operated with different temperature differences between the saturator and the condenser block yielding smallest detectable particle sizes (dp50 – as 50% detection "cut off" diameters of 6 nm, 11 nm, and 15 nm, respectively, at ambient pressure of 70 hPa. The fourth COPAS channel is operated with an aerosol heating line (250°C for a determination of the non-volatile number of particles. The heating line is experimentally proven to volatilize pure H2SO4-H2O particles for a particle diameter (dp range of 11 nm<dp<200 nm.

    Additionally this study includes investigation to exclude auto-nucleation of the working fluid inside the CPCs. An instrumental inter-comparison (cross-correlation has been performed for several measurement flights and mission flights in the Arctic and the Tropics are discussed. Finally, COPAS measurements are used for an aircraft plume crossing analysis.

  5. Experimental characterization of the COndensation PArticle counting System for high altitude aircraft-borne application

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2009-06-01

    Full Text Available A characterization of the ultra-fine aerosol particle counter COPAS (COndensation PArticle counting System for operation on board the Russian high altitude research aircraft M-55 Geophysika is presented. The COPAS instrument consists of an aerosol inlet and two dual-channel continuous flow Condensation Particle Counters (CPCs operated with the chlorofluorocarbon FC-43. It operates at pressures between 400 and 50 hPa for aerosol detection in the particle diameter (dp range from 6 nm up to 1 μm. The aerosol inlet, designed for the M-55, is characterized with respect to aspiration, transmission, and transport losses. The experimental characterization of counting efficiencies of three CPCs yields dp50 (50% detection particle diameter of 6 nm, 11 nm, and 15 nm at temperature differences (ΔT between saturator and condenser of 17°C, 30°C, and 33°C, respectively. Non-volatile particles are quantified with a fourth CPC, with dp50=11 nm. It includes an aerosol heating line (250°C to evaporate H2SO4-H2O particles of 11 nm<dp<200 nm at pressures between 70 and 300 hPa. An instrumental in-flight inter-comparison of the different COPAS CPCs yields correlation coefficients of 0.996 and 0.985. The particle emission index for the M-55 in the range of 1.4–8.4×1016 kg−1 fuel burned has been estimated based on measurements of the Geophysika's own exhaust.

  6. Carbon dioxide, hydrographic, and chemical data obtained during the R/Vs Roger Revelle and Thomas Thompson repeat hydrography cruises in the Pacific Ocean: CLIVAR CO2 sections P16S-2005 (9 January - 19 February, 2005) and P16N-2006 (13 February - 30 March, 2006)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, Alex [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Carbon Dioxide Information Analysis Center; Feely, R. A. [Pacific Marine Environmental Laboratory, NOAA, Seattle, WA (United States); Sabine, C. L. [Pacific Marine Environmental Laboratory, NOAA, Seattle, WA (United States); Millero, F. J. [University of Miami, Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Langdon, C. [University of Miami, Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Dickson, A. G. [Univ. of California, San Diego, CA (United States). Scripps Institution of Oceanography; Fine, R. A. [University of Miami, Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Bullister, J. L. [Pacific Marine Environmental Laboratory, NOAA, Seattle, WA (United States); Hansell, D. A. [University of Miami, Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Carlson, C. A. [Univ. of California, Santa Barbara, CA (United States); Sloyan, B. M. [Woods Hole Oceanographic Institution, Woods Hole, MA (United States); McNichol, A. P. [Woods Hole Oceanographic Institution, Woods Hole, MA (United States); Key, R. M. [Princeton Univ., NJ (United States); Byrne, R. H. [Univ. of South Florida, Tampa, FL (United States); Wanninkhof, R. [Atlantic Oceanographic and Meteorological Laboratory, NOAA, Miami, FL (United States)

    2009-05-01

    This report presents methods, and analytical and quality control procedures for salinity, oxygen, nutrients, total carbon dioxide (TCO2), total alkalinity (TALK), pH, discrete CO2 partial pressure (pCO2), dissolved organic carbon (DOC), chlorofluorocarbons (CFCs), radiocarbon, δ13C, and underway carbon measurements performed during the P16S-2005 (9 January - 19 February 2005) and P16N-2006 (13 February - 30 March, 2006) cruises in the Pacific Ocean. The research vessel (R/V) Roger Revelle departed Papeete, Tahiti, on January 9, 2005 for the Repeat Section P16S, nominally along 150°W, ending in Wellington, New Zealand, on February 19. During this cruise, samples were taken from 36 depths at 111 CTD stations between 16°S and 71°S. The Repeat Section P16N, nominally along 152°W, consisted of two legs. Leg 1 started on February 13, 2006 in Papeete, Tahiti, and finished on March 3, in Honolulu, Hawaii. The R/V Thomas G. Thompson departed Honolulu for Leg 2 on March 10, 2006 and arrived in Kodiak, Alaska, on March 30. During the P16N cruises, samples were taken from 34 or 36 depths at 84 stations between 17°S and 56.28°N. The research conducted on these cruises was part of a series of repeat hydrography sections jointly funded by the National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation (NSF) as part of the Climate Variability Program (CLIVAR)/CO2 Repeat Hydrography Program. The P16S and P16N data sets are available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center (CDIAC). The NDP consists of the oceanographic data files and this printed documentation, which describes the procedures and methods used to obtain the data.

  7. Impacts of urbanization on groundwater quality and recharge in a semi-arid alluvial basin

    Science.gov (United States)

    Carlson, Mark A.; Lohse, Kathleen A.; McIntosh, Jennifer C.; McLain, Jean E. T.

    2011-10-01

    SummaryThe management of groundwater resources is paramount in semi-arid regions experiencing urban development. In the southwestern United States, enhancing recharge of urban storm runoff has been identified as a strategy for augmenting groundwater resources. An understanding of how urbanization may impact the timing of groundwater recharge and its quality is a prerequisite for mitigating water scarcity and identifying vulnerability to contamination. We sampled groundwater wells along the Rillito Creek in southern Arizona that had been previously analyzed for tritium in the late 1980s to early 1990s and analyzed samples for tritium ( 3H) and helium-3 ( 3H/ 3He) to evaluate changes in 3H and age date groundwaters. Groundwater samples were also analyzed for chlorofluorocarbons (CFCs) and basic water quality metrics. Substantial changes in 3H values from waters sampled in the early 1990s compared to 2009 were identified after accounting for radioactive decay and indicate areas of rapid recharge. 3H- 3He groundwater ages ranged from 22 years before 2009 to modern recharge. CFC-11, -12 and -113 concentrations were anomalously high across the basin, and non-point source pollution in runoff and/or leaky infrastructure was identified as the most plausible source of this contamination. CFCs were strongly and positively correlated to nitrate ( r2 = 0.77) and a mobile trace metal, nickel ( r2 = 0.71), suggesting that solutes were derived from a similar source. Findings from this study suggest new waters from urban non-point sources are contributing to groundwater recharge and adversely affecting water quality. Reducing delivery of contaminants to areas of focused recharge will be critical to protect future groundwater resources.

  8. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (WOCE Section A10, December 1992-January 1993)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, A.

    1998-12-01

    This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) and total alkalinity (TALK) at hydrographic stations, as well as the underway partial pressure of CO{sub 2} (pCO{sub 2}) during the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (Section A10). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Rio de Janeiro on December 27, 1992, and ended after 36 days at sea in Capetown, South Africa, on January 31, 1993. Measurements made along WOCE Section A10 included pressure, temperature, and salinity [measured by conductivity, temperature, and depth (CTD) sensor], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-1 1 , CFC-12), TCO{sub 2}, TALK, and underway pCO{sub 2}. The TCO{sub 2} was measured by using two Single-Operator Multiparameter Metabolic Analyzers (SOMMAs) for extracting CO{sub 2} from seawater samples that were coupled to a coulometer for detection of the extracted CO{sub 2}. The overall precision and accuracy of the analyses was {+-} 1.9 {micro}mol/kg. Samples collected for TALK were measured by potentiometric titration; precision was {+-}2.0 {micro}mol/kg. Underway pCO{sub 2} was measured by infrared photometry with a precision of {+-} 2.0 {micro}atm. The work aboard the R/V Meteor was supported by the U.S. Department of Energy under contract DE-AC02-76CHOO016, and the Bundesministerium fir Forschung und Technologies through grants 03F0545A and MPG 099/1.

  9. New Delivery Systems and Propellants

    Directory of Open Access Journals (Sweden)

    Myrna Dolovich

    1999-01-01

    Full Text Available The removal of chlorofluorocarbon (CFC propellants from industrial and household products has been agreed to by over 165 countires of which more than 135 are developing countries. The timetable for this process is outlined in the Montreal Protocol on Substances that Deplete the Ozone Layer document and in several subsequent amendments. Pressured metered dose inhalers (pMDIs for medical use have been granted temporary exemptions until replacement formulations, providing the same medication via the same route, and with the same efficacy and safety profiles, are approved for human use. Hydrofluoroalkanes (HFAs are the alternative propellants for CFCs-12 and -114. Their potential for damage to the ozone layer is nonexistent, and while they are greenhouse gases, their global warming potential is a fraction (one-tenth of that of CFCs. Replacement formulations for almost all inhalant respiratory medications have been or are being produced and tested; in Canada, it is anticipated that the transition to these HFA or CFC-free pMDIs will be complete by the year 2005. Initially, an HFA pMDI was to be equivalent to the CFC pMDI being replaced, in terms of aerosol properties and effective clinical dose. However, this will not necessarily be the situation, particularly for some corticosteroid products. Currently, only one CFC-free formulation is available in Canada – Airomir, a HFA salbutamol pMDI. This paper discusses the in vitro aerosol characteristics, in vivo deposition and clinical data for several HFA pMDIs for which there are data available in the literature. Alternative delivery systems to the pMDI, namely, dry powder inhalers and nebulizers, are briefly reviewed.

  10. A Coupled Model Study on the Intensification of the Asian Summer Monsoon in IPCC SRES Scenarios

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Asian summer monsoon is an important part of the climate system. Investigating the response of the Asian summer monsoon to changing concentrations of greenhouse gases and aerosols will be meaningful to understand and predict climate variability and climate change not only in Asia but also globally. In order to diagnose the impacts of future anthropogenic emissions on monsoon climates, a coupled general circulation model of the atmosphere and the ocean has been used at the Max-Planck-Institute for Meteorology. In addition to carbon dioxide, the major well mixed greenhouse gases such as methane, nitrous oxide, several chlorofluorocarbons, and CFC substitute gases are prescribed as a function of time. The sulfur cycle is simulated interactively, and both the direct aerosol effect and the indirect cloud albedo effect are considered.Furthermore, changes in tropospheric ozone have been pre-calculated with a chemical transport model and prescribed as a function of time and space in the climate simulations. Concentrations of greenhouse gases and anthropogenic emissions of sulfur dioxide are prescribed according to observations (1860-1990) and projected into the future (1990-2100) according to the Scenarios A2 and B2 in Special Report on Emissions Scenarios (SRES, Nakicenovic et al., 2000) developed by the Intergovernmental Panel on Climate Change (IPCC). It is found that the Indian summer monsoon is enhanced in the scenarios in terms of both mean precipitation and interannual variability. An increase in precipitation is simulated for northern China but a decrease for the southern part. Furthermore, the simulated future increase in monsoon variability seems to be linked to enhanced ENSO variability towards the end of the scenario integrations.

  11. European emissions of halogenated greenhouse gases inferred from atmospheric measurements.

    Science.gov (United States)

    Keller, Christoph A; Hill, Matthias; Vollmer, Martin K; Henne, Stephan; Brunner, Dominik; Reimann, Stefan; O'Doherty, Simon; Arduini, Jgor; Maione, Michela; Ferenczi, Zita; Haszpra, Laszlo; Manning, Alistair J; Peter, Thomas

    2012-01-01

    European emissions of nine representative halocarbons (CFC-11, CFC-12, Halon 1211, HCFC-141b, HCFC-142b, HCFC-22, HFC-125, HFC-134a, HFC-152a) are derived for the year 2009 by combining long-term observations in Switzerland, Italy, and Ireland with campaign measurements from Hungary. For the first time, halocarbon emissions over Eastern Europe are assessed by top-down methods, and these results are compared to Western European emissions. The employed inversion method builds on least-squares optimization linking atmospheric observations with calculations from the Lagrangian particle dispersion model FLEXPART. The aggregated halocarbon emissions over the study area are estimated at 125 (106-150) Tg of CO(2) equiv/y, of which the hydrofluorocarbons (HFCs) make up the most important fraction with 41% (31-52%). We find that chlorofluorocarbon (CFC) emissions from banks are still significant and account for 35% (27-43%) of total halocarbon emissions in Europe. The regional differences in per capita emissions are only small for the HFCs, while emissions of CFCs and hydrochlorofluorocarbons (HCFCs) tend to be higher in Western Europe compared to Eastern Europe. In total, the inferred per capita emissions are similar to estimates for China, but 3.5 (2.3-4.5) times lower than for the United States. Our study demonstrates the large benefits of adding a strategically well placed measurement site to the existing European observation network of halocarbons, as it extends the coverage of the inversion domain toward Eastern Europe and helps to better constrain the emissions over Central Europe.

  12. Why CO2 cools the middle atmosphere - a consolidating model perspective

    Science.gov (United States)

    Goessling, Helge F.; Bathiany, Sebastian

    2016-08-01

    Complex models of the atmosphere show that increased carbon dioxide (CO2) concentrations, while warming the surface and troposphere, lead to lower temperatures in the stratosphere and mesosphere. This cooling, which is often referred to as "stratospheric cooling", is evident also in observations and considered to be one of the fingerprints of anthropogenic global warming. Although the responsible mechanisms have been identified, they have mostly been discussed heuristically, incompletely, or in combination with other effects such as ozone depletion, leaving the subject prone to misconceptions. Here we use a one-dimensional window-grey radiation model of the atmosphere to illustrate the physical essence of the mechanisms by which CO2 cools the stratosphere and mesosphere: (i) the blocking effect, associated with a cooling due to the fact that CO2 absorbs radiation at wavelengths where the atmosphere is already relatively opaque, and (ii) the indirect solar effect, associated with a cooling in places where an additional (solar) heating term is present (which on Earth is particularly the case in the upper parts of the ozone layer). By contrast, in the grey model without solar heating within the atmosphere, the cooling aloft is only a transient blocking phenomenon that is completely compensated as the surface attains its warmer equilibrium. Moreover, we quantify the relative contribution of these effects by simulating the response to an abrupt increase in CO2 (and chlorofluorocarbon) concentrations with an atmospheric general circulation model. We find that the two permanent effects contribute roughly equally to the CO2-induced cooling, with the indirect solar effect dominating around the stratopause and the blocking effect dominating otherwise.

  13. Laboratory test results on the thermal resistance of polyisocyanurate foamboard insulation blown with CFC-11 substitutes: A cooperative industry/government project

    Energy Technology Data Exchange (ETDEWEB)

    McElroy, D.L.; Graves, R.S.; Yarbrough, D.W.; Weaver, F.J.

    1991-09-01

    The fully halogenated chlorofluorocarbon gases (CFC-11 and CFC-12) are used as blowing agents for foam insulations for building and appliance applications. The thermal resistance per unit thickness of these insulations is greater than that of other commercially available insulations. Mandated reductions in the production of these chemicals may lead to less efficient substitutes and increase US energy consumption by one quad or more. This report describes laboratory thermal and aging tests on a set of industry-produced, experimental polyisocyanurate (PIR) laminate boardstock to evaluate the viability of hydrochlorofluorocarbons (HCFSs) as alternative blowing agents to chlorofluorcarbon-11 (CFC-11). The PIR boards were blown with five gases: CFC-11, HCFC- 123, HCFC-141b, and 50/50 and 65/35 blends of HCFC-123/HCFC-141b. These HCFC gases have a lower ozone depletion potential than CFC-11 or CFC-12. Apparent thermal conductivity (k) was determined from 0 to 50{degrees}C. Results on the laminate boards provide an independent laboratory check on the increase in k observed for field exposure in the Roof Thermal Research Apparatus (RTRA). The measured laboratory increase in k was between 8 and 11% after a 240-d field exposure in the RTRA. Results are reported on a thin-specimen, aging procedure to establish the long-term thermal resistance of gas-filled foams. These thin specimens were planed from the industry-produced boardstock foams and aged at 75 and 150{degrees}F for up to 300 d. The resulting k-values were correlated with an exponential dependency on (diffusion coefficient {times} time){sup {1/2}}/thickness and provided diffusion coefficients for air components into, and blowing agent out of, the foam. This aging procedure was used to predict the five-year thermal resistivity of the foams. The thin-specimen aging procedure is supported with calculations by a computer model for aging of foams. 43 refs., 33 figs., 25 tabs.

  14. Past Changes in the Vertical Distribution of Ozone Part 1: Measurement Techniques, Uncertainties and Availability

    Science.gov (United States)

    Hassler, B.; Petropavlovskikh, I.; Staehelin, J.; August, T.; Bhartia, P. K.; Clerbaux, C.; Degenstein, D.; Maziere, M. De; Dinelli, B. M.; Dudhia, A.; Dufour, G.; Frith, S. M.; Froidevaux, L.; Godin-Beekmann, S.; Granville, J.; Harris, N. R. P.; Hoppel, K.; Hubert, D.; Kasai, Y.; Kurylo, M. J.; Kyrola, E.; Lambert, J.-C.; Levelt, P. F.; McElroy, C. T.; McPeters, R. D.; Munro, R.; Nakajima, H.; Parrish, A.; Raspollini, P.; Remsberg, E. E.; Rosenlof, K. H.; Rozanov, A.; Sano, T.; Sasano, Y.; Shiotani, M.; Zawodny, J. M.

    2014-01-01

    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. Tradable emission quotas in Scandinavia; Omsettelige utslippskvoter i Norden

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This report discusses the trading of emission quotas of greenhouse gases in Scandinavia. It begins with a study of the experience with quotas of SO{sub 2} and other emissions in U.S.A., with tradable fish quotas in Iceland and New Zealand and with tradable production quotas for chlorofluorocarbons (CFCs). It then sketches possible systems, structure and actors for a Scandinavian quota system. One of the motivations behind a Scandinavian quota system is that tradable quotas can be a cost-effective instrument and help reduce the costs of emission reductions in Scandinavia. Another motivation would be that it would help to solve the problems caused by the considerable weather-induced variation in the CO{sub 2} emissions from the power sector. Reducing the emission of greenhouse gases is a responsibility of the national governments. If it is undesirable that individual actors should trade quotas of their own accord, then intergovernmental trade with quotas may be coupled to the use of other means within each country to keep the country`s total quota within its limit. A system including private actors must meet some basic requirements to work well: (1) it must have a sufficiently large number of actors with different measure costs, (2) it must be trusted by all depending on it, (3) it must be flexible, and (4) it must impose upon the trade as few restrictions as possible. The system should include most of the greenhouse gases, not only CO{sub 2}. It may be useful, however, to start with a simple system comprising only CO{sub 2} emission and the report is essentially restricted to CO{sub 2}. Three different quota systems are discussed, their initial distribution and time horizons. The origin of a market for quota trading, control measures and management of the quota system are also discussed. 18 refs.

  16. Influence of the Halogen Activation on the Ozone Layer in XXIst Century

    Science.gov (United States)

    Larin, Igor; Aloyan, Artash; Yermakov, Alexandr

    2016-04-01

    The aim of the work is to evaluate a possible effect of heterophase chemical reactions (HCR) with participation of reservoir gases (ClONO2, HCl) and sulfate particles of the Junge layer on the ozone layer at mid-latitudes in the XXI century, which could be relevant for more accurate predicting a recovery of the ozone layer, taking into account that just these processes were the main cause of the ozone depletion at the end of XXth century. Required for calculating the dynamics of GHR data on the specific volume/surface of the sulfate aerosols in the lower stratosphere were taken from the data of field experiments. Their physico-chemical properties (chemical composition, density, water activity and free protons activity et al.) have been obtained with help of thermodynamic calculations (Atmospheric Inorganic Model, AIM). Altitude concentration profiles of individual gas components, as well as temperature and relative humidity (RH) at a given geographic location and season have been calculated using a two-dimensional model SOCRATES. The calculations have been made for the conditions of June 1995, 2040 and 2080 at 15 km altitude and 50° N latitude. It has been shown that the rate of ozone depletion as a result of processes involving halogen activation for the given conditions in 2040, 2080 is about 35% lower than a corresponding value in 1995 (a year of maximum effect of halogen activation). From this we can conclude that in the XXI century, despite the natural decline of ozone-depleting chlorofluorocarbons. processes of halogen activation of the ozone depletion with participation of sulfate aerosols should be taken into account in the calculations of the recovery of the ozone layer at mid-latitudes.

  17. What to do about greenhouse warming: Look before you leap

    International Nuclear Information System (INIS)

    Greenhouse warming has emerged as one of the most complex and controversial environmental foreign-policy issues of the 1990s. Carbon dioxide (CO2), generated from the burning of oil, gas, and coal, is thought to enhance the natural greenhouse effect that has kept the planet warm for billions of years. Some scientists predict drastic climatic changes in the 21st Century. It is a foreign-policy issue because the US has taken a more cautious approach to dealing with CO2 emissions than have many industrialized nations. Wide acceptance of the Montreal Protocol, which limits and rolls back the manufacture of chlorofluorocarbons (CFCs) to protect the ozone layer, has encouraged environmental activists at international conferences the past three years to call for similar controls on CO2 from fossil-fuel burning. These activists are disappointed with the White House for not supporting immediate action. But should the US assume leadership in a hastily-conceived campaign that could cripple the global economy, or would it be more prudent to assure first, through scientific research, that the problem is both real and urgent? The authors sum up their conclusions in a simple message: The scientific base for a greenhouse warming is too uncertain to justify drastic action at this time. There is little risk in delaying policy responses to this century-old problem since there is every expectation that scientific understanding will be substantially improved within the next decade. Instead of premature and likely ineffective controls on fuel use that would only slow down CO2, the same resources could be used to increase our economic and technological resilience so that we can apply specific remedies as necessary to reduce climate change or to adapt to it. Prudent steps now include energy conservation and efficiency increases and make economic sense even without the threat of greenhouse warming

  18. The Evaluation of Climate Change Risks

    Directory of Open Access Journals (Sweden)

    Constantin POPESCU

    2012-11-01

    Full Text Available Nowadays, it is acknowledged that climatic changes represent a serious threat for the environment and, so, this problem has been approached at numerous conferences, conventions and summits. The climate is strongly influenced by the changes in the atmospheric concentrations of certain gases that hold the solar radiations on the Earth’s surface (the greenhouse effect. The water vapors and the carbon dioxide (CO2 present in the atmosphere have always generated a natural greenhouse effect, without which the Earth surface would be 33o C lower than it is today. Other greenhouse gases are: methane (CH4, nitrogen protoxide (N2O, and the halogenated compounds such as chlorofluorocarbons (CFCs. During the last hundred years, man’s activity has led to the increase of the atmospheric concentration of the greenhouse gases and of other pollutants, its consequence being the increase of the average global temperature. Although it has not been calculated exactly how much of this warming can be attributed to the greenhouse gases, there is evidence that human activity contributes to global warming. The main causes leading to the accentuation of the greenhouse effect are the burning of the fossil fuels, deforestations, cement production, waste disposal, refrigeration etc. The climatic changes triggered by the greenhouse gases will have consequences that have already made themselves visible, causing: the increase of the sea level and the possible flooding of the low areas; the melting of the icecap; the modification of the precipitations regime, with consequences like the increase of the floods and droughts frequency; changes in the occurrence of climatic extremes, especially in the occurrence of the high, extreme temperatures. All these will have a direct impact on ecosystems, health, some key economic sectors such as agriculture and on water resources.

  19. Win-win solutions for the climate and the ozone layer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    After some 20 years of effective action under the Montreal Protocol on Substances that Deplete the Ozone Layer, governments are now addressing the fact that chlorofluorocarbons (CFCs) and some of the chemicals used as substitutes for them are greenhouse gases that together contribute significantly to global warming. Policymakers face a serious dilemma. Stopping the destruction of the ozone layer is vital for protecting human health and vulnerable ecosystems. But minimizing climate change and its expected consequences for both manmade and natural systems is also essential. What can be done to tackle both the ozone and climate change challenges without making unacceptable trade-offs or compromises? To answer this question, the governing bodies of the Montreal Protocol and the United Nations Framework Convention on Climate Change jointly requested a scientific and technical assessment. Working Groups I (science) and III (mitigation) of the Intergovernmental Panel on Climate Change (IPCC), together with the ozone regime's Technology and Economic Assessment Panel (TEAP), responded by producing a Special Report in April 2005 entitled 'Safeguarding the ozone layer and the global climate system: issues related to hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs)'. Based on the most up-to-date scientific and technical literature available, the report concludes that it will indeed be possible to maintain the Montreal Protocol's momentum while achieving the goals of the Climate Change Convention and its Kyoto Protocol. It identifies a portfolio of solutions that - if energetically applied - could cut the global warming contribution of CFCs and their replacements in half by the year 2015 compared to 2002 levels. This reduction can be achieved even though global economic growth will boost demand for the functions traditionally provided by CFCs. UNEP has produced this short public information booklet with the aim of making the Special Report

  20. Using environmental tracers to assess the extent of river-groundwater interaction in a quarried area of the English Chalk

    Energy Technology Data Exchange (ETDEWEB)

    Darling, W.G., E-mail: wgd@bgs.ac.uk [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom); Gooddy, D.C. [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom); Riches, J. [Thames Water Utilities Limited, Rose Kiln Court, Rose Kiln Lane, Reading RG2 0BY (United Kingdom); Wallis, I. [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom)

    2010-07-15

    The Swanscombe area of Kent, SE England represents a typical example of a heavily quarried Chalk area currently undergoing re-development. Because the Chalk is also an important aquifer, a good understanding of groundwater movement is required if environmental impacts are to be minimised and the water resource maximised. In particular, the nature of the relationship between the River Darent and groundwater in the Swanscombe Chalk Block requires better characterisation. Here, 'environmental tracers' in the form of ambient concentrations of stable isotopes, chlorofluorocarbons (CFCs), sulphur hexafluoride (SF{sub 6}) and tritium ({sup 3}H) are used to investigate this and other aspects of groundwater movement in the vicinity of the quarries. Stable isotopic contrasts indicate little evidence for widespread river infiltration to the regional Chalk aquifer, although stable isotope and {sup 3}H data suggest that 20-35% of the abstraction by river-valley public water supply boreholes may be derived from the river. The CFCs, while present at above-modern concentrations in almost all groundwaters, can be used as tracers, indicating basically S-N flowpaths in the area south of the quarries, though sub-karstic conduits associated with areas of Palaeogene cover add a level of uncertainty at the local scale. Simple piston flow residence times based on SF{sub 6} range from 1 to 17 a, but the data are probably better interpreted in terms of mixing between varying amounts of modern recharge derived from the south and deeper stored groundwater. The information gained from environmental tracers can therefore contribute to effective resource management.

  1. TEWI Analysis: Its Utility, Its Shortcomings, and Its Results

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, V.D.; Fischer, S.K.; Sand, J.R.

    1999-09-13

    The past decade has been a challenging time for the refrigeration and air conditioning industry worldwide. Provisions of the Montreal Protocol and its amendments require the phaseout of chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) compounds that have been used extensively as insulating foam blowing agents and refrigerants in refrigeration systems, heat pumps, and air conditioners. In response, hydrofluorocarbon (HFC) compounds were proposed, developed, and are starting to be used as the primary alternatives to CFCs and HCFCs. However, in 1997 under the Kyoto Protocol, industrialized nations have agreed to roll back emissions of HCFCs, carbon dioxide (CO*), and four other greenhouse gases which threaten to cause excessive global warming. The US. Department of Energy and the Alternative Fluorocarbon Environmental Acceptability Study (AFEAS) jointly sponsored research projects to identify the major applications of CFCs, HCFCs, and HFCs and to examine the impacts of these compounds and the energy use of applications employing these compounds on global warming. The five major uses of fluorocarbons based on sales were automobile air conditioning, supermarket refrigeration, unitary heat pumps and air conditioning, chillers for cooling large office buildings, and household refrigeration. Almost all of the refrigerants used in these applications are global warming gases, and if the refrigerant leaks out of the system during operation, is lost during maintenance or is not recovered when the system is scraped, it contributes to global warming. But, it is also true that the energy consumed by refrigeration and air conditioning systems, in the form of electricity or the direct combustion of fossil fuel, results in the release of CO*, the primary cause of atmospheric global warming.

  2. Groundwater dating applied for geological disposal of radioactive waste. A review of methods employed worldwide

    International Nuclear Information System (INIS)

    Groundwater dating methods employed in projects to develop deep geological repositories for radioactive wastes, or to research technologies and methods that may be used when developing a repository, have been reviewed. The reviewed projects are being, or have been, undertaken in Japan, Finland, Sweden, Belgium, the UK, Germany, France, Switzerland, Canada and the U.S.A.. A wide range of actual and potential repository host rock types and hydrogeological settings have been investigated. The most commonly used dating methods are based on physical hydrogeology and measurements of δ18O/16O, 3H, 14C, 36Cl and 4He in groundwater or pore water. Only two of the reviewed projects have used noble gas data to estimate recharge temperatures, and hence deduce the timing of recharge. A single project used 129I. Analyses of U-series isotopes have generally not been used successfully, owing to the complex radiological and redox processes that influence U migration, which complicates the interpretation of such U-series data. None of the reviewed projects have used methods based on Tritium (3H)–Helium-3 (3He), Chlorofluorocarbons (CFCs) or 85Kr. These methods have not been needed because they indicate the presence of water recharged within the last ca. 50 – ca. 60 years, which could be identified readily at all the sites by the presence of 3H. In the case of 81Kr, sampling and analytical difficulties have probably prevented its use. Recently, improved analytical techniques enable smaller samples to be analyzed, but 81Kr gives similar information to 36Cl, which can be investigated more easily. Whatever the combinations of methods that have been used in a particular program, their results have invariably been interpreted in combination with one another and in the context of other information that is available for the investigated site. That is, a particular groundwater dating method is never applied in isolation. (author)

  3. Halide test agent replacement study

    Energy Technology Data Exchange (ETDEWEB)

    Banks, E.M.; Freeman, W.P.; Kovach, B.J. [and others

    1995-02-01

    The intended phaseout of the chlorofluorocarbons (CFCs) from commercial use required the evaluation of substitute materials for the testing for leak paths through both individual adsorbers and installed adsorbent banks. The American Society of Mechanical Engineers (ASME) Committee on Nuclear Air and Gas Treatment (CONAGT) is in charge of maintaining the standards and codes specifying adsorbent leak test methods for the nuclear safety related air cleaning systems. The currently published standards and codes cite the use of R-11, R-12 and R-112 for leak path test agents. All of these compounds are CFCs. There are other agencies and organizations (USDOE, USDOD and USNRC) also specifying testing for leak paths or in some cases for special life tests using the above compounds. The CONAGT has recently developed criteria for the suitability evaluation of substitute test agents. On the basis of these criteria, several compounds were evaluated for their acceptability as adsorbent bed leak and life test agents. The ASME CONAGT Test Agent Qualification Criteria. The test agent qualification is based on the following parameters: (1) Similar retention times on activated carbons at the same concentration levels as one of the following: R-11, R-12, R-112 or R-112a. (2) Similar lower detection limit sensitivity and precision in the concentration range of use as R-11, R-12, R-112 and R-112a. (3) Gives the same in-place leak test results as R-11, R-12, R-112, or R-112a. (4) Chemical and radiological stability under the use conditions. (5) Causes no degradation of the carbon and its impregnant or of the other NATS components under the use conditions. (6) Is listed in the USEPA Toxic Substances Control Act (TSCA) inventory for commercial use.

  4. Hydrogen based global renewable energy network

    Energy Technology Data Exchange (ETDEWEB)

    Akai, Makoto [Mechanical Engineering Laboratory, AIST, MITI, Namiki, Tsukuba (Japan)

    1993-12-31

    In the last quarter of this century, global environmental problem has emerged as a major scientific, political and social issue. Specific Problems include: depletion of ozone layer by chlorofluorocarbons (CFCs), acid rain, destruction of tropical forests and desertification, pollution of the sea and global wanning due to the greenhouse effect by carbon dioxide and others. Among these problems, particular attention of the world has been focused on the global warming because it has direct linkage to energy consumption which our economic development depends on so far. On the other hand, the future program of The Sunshine Project for alternative energy technology R&D, The Moonlight Project for energy conservation technology R&D, and The Global Environmental Technology Program for environmental problem mitigating technology R&D which are Japan`s national projects being promoted by their Agency of Industrial Science and Technology (AIST) in the Ministry of International Trade and Industry have been reexamined in view of recent changes in the situations surrounding new energy technology. In this regard, The New Sunshine Program will be established by integrating these three activities to accelerate R&D in the field of energy and environmental technologies. In the reexamination, additional stress has been laid on the contribution to solving global environmental problem through development of clean renewable energies which constitute a major part of the {open_quotes}New Earth 21{close_quotes}, a comprehensive, long-term and international cooperative program proposed by MITI. The present paper discusses the results of feasibility study on hydrogen energy system leading to the concept of WE-NET following a brief summary on R&D status on solar and wind energy in Japan.

  5. Flow paths and mixing properties of groundwater using hydrogeochemistry and environmental tracers in the southwestern area of Jeju volcanic island

    Science.gov (United States)

    Koh, Dong-Chan; Ha, Kyoochul; Lee, Kwang-Sik; Yoon, Yoon-Yeol; Ko, Kyung-Seok

    2012-04-01

    SummaryGroundwater from springs, test boreholes and domestic wells was investigated to assess the flow system of basaltic aquifers at base-flow conditions in the southwestern part of Jeju Island, South Korea. This study utilized hydrogeochemical parameters and environmental tracers of 18O, 2H, 3H and chlorofluorocarbons (CFCs), which showed that well-connected flow paths exist between coastal springs regardless of flow rates. In contrast, test boreholes near the coastal springs exhibited various flow paths. Nitrate concentrations were much higher than baseline values in mountainous groundwater while those decreased in coastal areas (<50 m asl) despite stronger anthropogenic land uses. Cl- was seemingly contributed from nitrate contamination sources and seawater sources were minimal due to low-permeability layers near sea level. The water-stable isotopes indicated little evaporation and were comparable to the local meteoric water line during the rainy season, which was confirmed by deuterium excess values, demonstrating that effective infiltration primarily occurs during the rainy season. From the effects of altitude on δ18O, the mean recharge altitudes for both mountainous and coastal springs were estimated as 300-400 m, which implies longer flow paths for the coastal springs. The relationship of CFC-12-CFC-113 and that of CFC-12-3H concordantly indicated that the groundwater consists mainly of binary mixtures composed of 15-25-year-old young water and old water with ages greater than 60 years. Lower nitrate levels in the coastal springs were well represented by the mixing models. Recharge altitudes for coastal springs increased up to 700 m, assuming that old water corresponds to high-altitude recharge, using the binary mixing model. Integration of hydrochemical and environmental tracer characteristics revealed that pahoehoe lava flows and hydrovolcanic tuffs play key roles in controlling the groundwater occurrence and quality.

  6. Greenhouse gas emissions in Sub-Saharan Africa

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.L.; Perlack, R.D.; Prasad, A.M.G.; Ranney, J.W.; Waddle, D.B.

    1990-11-01

    Current and future carbon emissions from land-use change and energy consumption were analyzed for Sub-Saharan Africa. The energy sector analysis was based on UN energy data tapes while the land-use analysis was based on a spatially-explicit land-use model developed specifically for this project. The impacts of different energy and land-use strategies on future carbon emissions were considered. (A review of anthropogenic emissions of methane, nitrous oxides, and chlorofluorocarbons in Sub-Saharan Africa indicated that they were probably minor in both a global and a regional context. The study therefore was focused on emissions of carbon dioxide.) The land-use model predicts carbon emissions from land use change and the amount of carbon stored in vegetation (carbon inventory) on a yearly basis between 1985 and 2001. Emissions and inventory are modeled at 9000 regularly-spaced point locations in Sub-Saharan Africa using location-specific information on vegetation type, soils, climate and deforestation. Vegetation, soils, and climate information were derived from continental-scale maps while relative deforestation rates(% of forest land lost each year) were developed from country-specific forest and deforestation statistics (FAO Tropical Forest Resources Assessment for Africa, 1980). The carbon emissions under different land use strategies in Sub-Saharan Africa were analyzed by modifying deforestation rates and altering the amount of carbon stored under different land uses. The considered strategies were: preservation of existing forests, implementation of agroforestry, and establishment of industrial tree plantations. 82 refs., 16 figs., 25 tabs.

  7. Fundamental differences between Arctic and Antarctic ozone depletion.

    Science.gov (United States)

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J; Min, Flora

    2014-04-29

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below -80 °C to -85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles. PMID:24733920

  8. Ozone depletion in the high latitude lower stratosphere - 1979-1990

    Science.gov (United States)

    Callis, Linwood B.; Boughner, Robert E.; Natarajan, Murali; Lambeth, James D.; Baker, Daniel N.

    1991-01-01

    Archived Stratospheric Aerosol and Gas Experiment (SAGE, SAGE II) and Solar and Backscattered Ultraviolet (SBUV) data are used to examine lower stratospheric O3 variations at 50 deg latitude in both hemispheres. These data indicate that from 1979 to 1985, 73-90 percent of the total O3 changes have occurred below approximately 25 km in altitude. Significant O3 depletions (up to 15 percent) have occurred in the partial column (127-15.8 mbar) in both hemispheres with indications of a recovery after 1985. Two-dimensional model simulations of O3 changes from 1979 to 1990 have been carried out. Comparisons with O3 data are presented. Model results suggest that by 1985, significant declines in global O3 were caused by destruction by odd nitrogen associated with long-term variations in the flux of precipitating relativistic electrons (2.6 percent); solar UV flux changes (1.8 percent); the dilution effect associated with the Antarctic O3 hole (1.2 percent); and atmospheric increases in CH4, N2O, and chlorofluorocarbons (0.4 percent). Analyses of drift-corrected SBUV and Total Ozone Mapping Spectrometer data and model calculations indicate that between 1979 and 1985, reductions of 4.3 to 4.8 percent in total column O3 averaged between 65 deg S and 65 deg N have occurred. Calculations indicate a full global O3 decline of 5.2 percent (peak-to-peak) or 6 percent (annual average) between 1979 and 1985 with a partial recovery between 1985 and 1989.

  9. Flunisolide hydrofluoroalkane with integrated spacer for treating asthma: an updated review.

    Science.gov (United States)

    Berger, William E; Tashkin, Donald P

    2015-01-01

    Flunisolide hydrofluoroalkane (HFA) with integrated spacer is the most recent reformulated inhaled corticosteroid (ICS) for asthma available in the United States. It is the only product that combines a corticosteroid extrafine aerosol with a built-in spacer. The potential clinical benefit of the flunisolide HFA formulation and its integrated spacer for treating persistent asthma was assessed through a comprehensive review of the published literature and data from the past 10 years focusing on (1) flunisolide, the molecule, and the impact of the HFA reformulation; (2) updated information on the anti-inflammatory response to flunisolide HFA, particularly in the distal airways; and (3) the usefulness of an integrated spacer. Flunisolide HFA was found effective and safe in clinical studies and comparable with the chlorofluorocarbon (CFC) formulation, but at about one-third the dose of flunisolide CFC, likely reflecting both the device and the particle size of the reformulated product. Compared with the CFC formulation, the extrafine aerosol and smaller particle size of flunisolide HFA substantially increased pulmonary deposition and decreased oropharyngeal deposition. The integrated spacer further enhanced the pulmonary/oropharyngeal deposition ratio. Examination of lung biopsy specimens indicated a favorable anti-inflammatory response to flunisolide HFA in peripheral airways. Pediatric studies showed no significant effects on growth. The data indicate that flunisolide HFA is a safe and effective maintenance therapy for asthma patients. The integrated spacer may provide an added advantage for patients, especially those who may be more likely to experience adverse effects of ICSs, both local and systemic, including children susceptible to adverse effects on growth.

  10. Nordic Seas and Arctic Ocean CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    E. Jeansson

    2010-02-01

    Full Text Available Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters have been retrieved from a large number of cruises and collected into a new database called CARINA (CARbon IN the Atlantic. These data have been merged into three sets of files, one for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS, the Atlantic (ATL and the Southern Ocean (SO. The first part of the CARINA database consists of three files, one for each CARINA region, containing the original, non-adjusted cruise data sets, including data quality flags for each measurement. These data have then been subject to rigorous quality control (QC in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the second part of the CARINA data product. This consists of three files, one for each CARINA region, which contain adjustments to the original data values based on recommendations from the CARINA QC procedures, along with calculated and interpolated values for some missing parameters.

    Here we present an overview of the QC of the CFC data for the AMS region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113, as well as carbon tetrachloride (CCl4. The Arctic Mediterranean Seas is comprised of the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. For the secondary QC of the CFCs we used a combination of tools, including the evaluation of depth profiles and CFC ratios, surface saturations and a crossover analysis. This resulted in a multiplicative adjustment of data from some cruises, while other data were flagged to be of questionable quality, which excluded them from the final data product.

  11. SI2N overview paper: ozone profile measurements: techniques, uncertainties and availability

    Science.gov (United States)

    Hassler, B.; Petropavlovskikh, I.; Staehelin, J.; August, T.; Bhartia, P. K.; Clerbaux, C.; Degenstein, D.; De Mazière, M.; Dinelli, B. M.; Dudhia, A.; Dufour, G.; Frith, S. M.; Froidevaux, L.; Godin-Beekmann, S.; Granville, J.; Harris, N. R. P.; Hoppel, K.; Hubert, D.; Kasai, Y.; Kurylo, M. J.; Kyrölä, E.; Lambert, J.-C.; Levelt, P. F.; McElroy, C. T.; McPeters, R. D.; Munro, R.; Nakajima, H.; Parrish, A.; Raspollini, P.; Remsberg, E. E.; Rosenlof, K. H.; Rozanov, A.; Sano, T.; Sasano, Y.; Shiotani, M.; Smit, H. G. J.; Stiller, G.; Tamminen, J.; Tarasick, D. W.; Urban, J.; van der A, R. J.; Veefkind, J. P.; Vigouroux, C.; von Clarmann, T.; von Savigny, C.; Walker, K. A.; Weber, M.; Wild, J.; Zawodny, J.

    2013-11-01

    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 is for each data set is also given.

  12. 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.

  13. Multimodel estimates of atmospheric lifetimes of long-lived ozone-depleting substances: Present and future

    Science.gov (United States)

    Chipperfield, M. P.; Liang, Q.; Strahan, S. E.; Morgenstern, O.; Dhomse, S. S.; Abraham, N. L.; Archibald, A. T.; Bekki, S.; Braesicke, P.; Di Genova, G.; Fleming, E. L.; Hardiman, S. C.; Iachetti, D.; Jackman, C. H.; Kinnison, D. E.; Marchand, M.; Pitari, G.; Pyle, J. A.; Rozanov, E.; Stenke, A.; Tummon, F.

    2014-03-01

    We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in the MBC value does not necessarily match a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modeled rates of ascent and horizontal mixing in the tropical midlower stratosphere. The model runs have been used to compute instantaneous and steady state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s, and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modeled lifetimes is small. For future assessments of stratospheric ozone, use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate.

  14. Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability

    Science.gov (United States)

    Hassler, B.; Petropavlovskikh, I.; Staehelin, J.; August, T.; Bhartia, P. K.; Clerbaux, C.; Degenstein, D.; De Mazière, M.; Dinelli, B. M.; Dudhia, A.; Dufour, G.; Frith, S. M.; Froidevaux, L.; Godin-Beekmann, S.; Granville, J.; Harris, N. R. P.; Hoppel, K.; Hubert, D.; Kasai, Y.; Kurylo, M. J.; Kyrölä, E.; Lambert, J.-C.; Levelt, P. F.; McElroy, C. T.; McPeters, R. D.; Munro, R.; Nakajima, H.; Parrish, A.; Raspollini, P.; Remsberg, E. E.; Rosenlof, K. H.; Rozanov, A.; Sano, T.; Sasano, Y.; Shiotani, M.; Smit, H. G. J.; Stiller, G.; Tamminen, J.; Tarasick, D. W.; Urban, J.; van der A, R. J.; Veefkind, J. P.; Vigouroux, C.; von Clarmann, T.; von Savigny, C.; Walker, K. A.; Weber, M.; Wild, J.; Zawodny, J. M.

    2014-05-01

    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. Effects of injected ice particles in the lower stratosphere on the Antarctic ozone hole

    Science.gov (United States)

    Nagase, H.; Kinnison, D. E.; Petersen, A. K.; Vitt, F.; Brasseur, G. P.

    2015-05-01

    The Antarctic ozone hole will continue to be observed in the next 35-50 years, although the emissions of chlorofluorocarbons (CFCs) have gradually been phased out during the last two decades. In this paper, we suggest a geo-engineering approach that will remove substantial amounts of hydrogen chloride (HCl) from the lower stratosphere in fall, and hence limit the formation of the Antarctic ozone hole in late winter and early spring. HCl will be removed by ice from the atmosphere at temperatures higher than the threshold under which polar stratospheric clouds (PSCs) are formed if sufficiently large amounts of ice are supplied to produce water saturation. A detailed chemical-climate numerical model is used to assess the expected efficiency of the proposed geo-engineering method, and specifically to calculate the removal of HCl by ice particles. The size of ice particles appears to be a key parameter: larger particles (with a radius between 10 and 100 µm) appear to be most efficient for removing HCl. Sensitivity studies lead to the conclusions that the ozone recovery is effective when ice particles are supplied during May and June in the latitude band ranging from 70°S to 90°S and in the altitude layer ranging from 10 to 26 km. It appears, therefore, that supplying ice particles to the Antarctic lower stratosphere could be effective in reducing the depth of the ozone hole. In addition, photodegradation of CFCs might be accelerated when ice is supplied due to enhanced vertical transport of this efficient greenhouse gas.

  16. Coherence of longterm stratospheric ozone time series for the study of ozone recovery in the northern mid-latitudes

    Science.gov (United States)

    Nair, Prijitha J.; Godin-Beekmann, Sophie; Pazmino, Andrea

    2010-05-01

    Since mid-to late 1980s decreasing amounts of ozone concentration has been observed in northern mid-latitudes mainly due to the ozone depleting chlorofluorocarbon loading in the stratosphere. Recent works indicate the stabilization of ozone loss in the mid-latitudes, in the upper stratosphere in particular. In order to further investigate the evolution of ozone in the mid-latitudes, a coherent dataset is required. As a first step, we diagnose the long term evolution of ozone at Observatoire de Haute Provence (OHP - 43.93°N, 5.71°E), one of the northern mid-latitude stations. In this study, we present the inter comparison of ozone measurements from OHP LIDAR with collocated SBUV, SAGEII, HALOE, MLS and GOMOS satellite observations as well as the ground based Ozonesondes and Umkehr measurements. A detailed statistical study on the relative differences of the compared measurements is performed to check any specific drifts with time. In addition, the seasonal and annual averages of the relative deviations are also checked to quantify agreement among the data. On average, all instruments show their best agreement with LIDAR between 20 and 40 km, where the differences are within 5%. The agreement with SAGEII measurements are remarkably good since it falls within 1% at 17-41 km. A similar result is also found from the Ozonesondes comparison at 22-31 km. Most comparisons exhibit slightly larger deviations below 20 and above 42 km, of about 10%. The LIDAR masurements are also compared to Umkehr measurements by converting its ozone number density to Dobson units for each Umkehr layer. The analysis reveals a negative bias in Umkehr data within -10% except at layer 6 (around 30 km).

  17. Lesson learned case study: What the history of ozone depelting chemical phaseout may teach us about how to approach international climate change policy

    Energy Technology Data Exchange (ETDEWEB)

    Younis, S.E. [Conceptual Engineering Group, Inc., Crofton, MD (United States); Verdonik, D.P. [Hughes Associates, Inc., Baltimore, MD (United States)

    1997-12-31

    The world approached the production phaseout of ozone depleting chemicals conservatively under the Vienna Convention. The initial tasks were to recognize the problem within the science field and make political leaders and people aware that the problem existed and was a real threat to environmental stability. Several years later, Meetings of the Parties to the Montreal Protocol to Protect the Stratospheric Ozone Layer began occurring regularly. Long term goals on production reduction levels of chlorofluorocarbons (CFCs) and halons were set. Rapid acceleration in production phaseout dates were implemented worldwide, impacting industry plans to research, develop, and implement replacements. The impacts were widespread from small cleaning processes to the defense of countries. The trials and tribulations that industries such as the foam, refrigeration, air conditioning, fire protection, and manufacturing industries have gone through to meet the accelerated challenges are great. This fight is not yet over. Alternatives have yet to be fully implemented, long term effects analysis are not yet completed, budgets have not caught up with the rapid phaseout, and supplies of ODCs are dwindling quickly, as well as increasing in cost at a rapid rate. This is being felt from car owner all the way up to the national defense of countries. The paper will briefly describe the historic events and developments that occurred to industry and the users, from a political, environmental, and business perspective. From this, valuable lessons can be learned and we can plan for the future well in advance, in order that we are not caught off guard again. A very real environmental problem exists with global climate change. This is being increasingly recognized by both political leaders and citizens alike. From what we have seen with ODC phaseout, we can potentially project what course the future.

  18. Overview of CFC replacement issues for household refrigeration

    Science.gov (United States)

    Vineyard, E. A.; Roke, L.; Hallett, F.

    In 1974, the famous ozone depletion theory of Rowland and Molina claimed that chlorofluorocarbons (CFCs) diffuse into the stratosphere where they are broken down by photolysis to release chlorine atoms that catalytically destroy ozone. Although the understanding of the science is still imperfect, there is little doubt that CFCs play a major role in the Antarctic ozone hole phenomenon and the decline in ozone observed in the rest of the world. Another issue that has become increasingly important is the potential of CFCs to change the earth's temperature and to modify the climate. While the main impact in global warming is made by increased concentrations of carbon dioxide, CFCs and other trace gases also contribute to this effect. In an effort to respond to the global environmental threat, a CFC protocol was adopted during a diplomatic conference in Montreal. This document, known as the Montreal Protocol, was ratified in 1988 and put into effect on January 1, 1989. In accordance with Article 6 of the Montreal Protocol, the countries that signed the agreement shall periodically assess the control measures provided for in the Protocol. As part of that assessment process, household refrigeration was investigated to determine the status of CFC-12 replacements. The conclusion was that much progress has been made towards finding a suitable replacement. Compressors designed for HFC-134a have efficiencies comparable to those for CFC-12 and acceptable reliability tests have been obtained with ester lubricants. In addition, other replacements such as R-152a and refrigerant mixtures exist, but will require more study. Cycle options, such as the Stirling cycle, may be viable, but are further out in the future. The impact of new refrigerants is expected to result in elimination of CFC-12 consumption in developed countries by 1997 and in developing countries by 2005.

  19. Compliance with the Clean Air Act Title VI Stratospheric Ozone Protection Program requirements at U.S. DOE Oak Ridge Reservation Facilities

    International Nuclear Information System (INIS)

    The Title VI Stratospheric Ozone Protection Program of the Clean Air Act (CAA) requires promulgation of regulations to reduce and prevent damage to the earth's protective ozone layer. Regulations pursuant to Title VI of the CAA are promulgated in the Code of Federal Regulations (CFR) at Title 40 CFR, Part 822. The regulations include ambitious production phaseout schedules for ozone depleting substances (ODS) including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, and methyl chloroform under 40 CFR 82, Subpart A. The regulations also include requirements for recycling and emissions reduction during the servicing of refrigeration equipment and technician certification requirements under Subpart F; provisions for servicing of motor vehicle air conditioners under Subpart B; a ban on nonessential products containing Class 1 ODS under Subpart C; restrictions on Federal procurement of ODS under Subpart D; labeling of products using ODS under Subpart E; and the Significant New Alternatives Policy Program under Subpart G. This paper will provide details of initiatives undertaken at US Department of Energy (DOE) Oak Ridge Reservation (ORR) Facilities for implementation of requirements under the Title VI Stratospheric Ozone Protection Program. The Stratospheric Ozone Protection Plans include internal DOE requirements for: (1) maintenance of ODS inventories; (2) ODS procurement practices; (3) servicing of refrigeration and air conditioning equipment; (4) required equipment modifications or replacement; (5) technician certification training; (6) labeling of products containing ODS; (7) substitution of chlorinated solvents; and (8) replacement of halon fire protection systems. The plans also require establishment of administrative control systems which assure that compliance is achieved and maintained as the regulations continue to develop and become effective

  20. Energy and global warming impacts of CFC alternative technologies for foam building insulations

    International Nuclear Information System (INIS)

    Chlorofluorocarbons (CFCS) have been used as blowing agents in foam insulation, as the working fluids in cooling and refrigeration equipment, and as solvents in general and precision cleaning applications since their introduction in the 1930s. The number of applications and volumes of CFCs used grew at a tremendous pace during the 1960s and 1970s, but in the mid-1980s it was confirmed that these extremely useful chemicals contribute to the destruction of stratospheric zone and that they are the primary cause of the CFCs have also been found to be second only to carbon dioxide as a factor causing increased greenhouse warming. These chemicals are being phased out of use rapidly to protect the ozone layer and it is very important that the replacements for CFCs do not result in a net increase in global warming by introducing less efficient processes that lead to higher energy use and increased carbon dioxide emissions. A study was conducted to identify those alternative chemicals and technologies that could replace CFCs in energy related applications before the year 2000, and to assess the total potential impact of those alternatives on global warming. The analysis for this project included an estimate of the direct effects from the release of blowing agents, refrigerants, and solvents into the atmosphere and the indirect effects of carbon dioxide emissions resulting from energy use for commercial and residential building insulation, household and commercial refrigeration, building and automobile air conditioning, and general metal and electronics solvent cleaning. This paper focuses on those aspects of the study relevant to building insulation. In general the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon alternatives for CFCs lead to large and sometimes dramatic reductions in total equivalent warming impact, lifetime equivalent C02 emissions (TEWI). Most of the reductions result from decreased direct effects without significant changes in energy use

  1. Estimated rates of groundwater recharge to the Chicot, Evangeline and Jasper aquifers by using environmental tracers in Montgomery and adjacent counties, Texas, 2008 and 2011

    Science.gov (United States)

    Oden, Timothy D.; Truini, Margot

    2013-01-01

    Montgomery County is in the northern part of the Houston, Texas, metropolitan area, the fourth most populous metropolitan area in the United States. As populations have increased since the 1980s, groundwater has become an important resource for public-water supply and industry in the rapidly growing area of Montgomery County. Groundwater availability from the Gulf Coast aquifer system is a primary concern for water managers and community planners in Montgomery County and requires a better understanding of the rate of recharge to the system. The Gulf Coast aquifer system in Montgomery County consists of the Chicot, Evangeline, and Jasper aquifers, the Burkeville confining unit, and underlying Catahoula confining system. The individual sand and clay sequences of the aquifers composing the Gulf Coast aquifer system are not laterally or vertically continuous on a regional scale; however, on a local scale, individual sand and clay lenses can extend over several miles. The U.S. Geological Survey, in cooperation with the Lone Star Groundwater Conservation District, collected groundwater-quality samples from selected wells within or near Montgomery County in 2008 and analyzed these samples for concentrations of chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium (3H), helium-3/tritium (3He/3H), helium-4 (4He), and dissolved gases (DG) that include argon, carbon dioxide, methane, nitrogen and oxygen. Groundwater ages, or apparent age, representing residence times since time of recharge, were determined by using the assumption of a piston-flow transport model. Most of the environmental tracer data indicated the groundwater was recharged prior to the 1950s, limiting the usefulness of CFCs, SF6, and 3H concentrations as tracers. In many cases, no tracer was usable at a well for the purpose of estimating an apparent age. Wells not usable for estimating an apparent age were resampled in 2011 and analyzed for concentrations of major ions and carbon-14 (14C). At six of

  2. Merging Energy Policy Decision Support, Education, and Communication: The 'World Energy' Simulation Role-Playing Game

    Science.gov (United States)

    Rooney-varga, J. N.; Franck, T.; Jones, A.; Sterman, J.; Sawin, E.

    2013-12-01

    To meet international goals for climate change mitigation and adaptation, as well as energy access and equity, there is an urgent need to explore and define energy policy paths forward. Despite this need, students, citizens, and decision-makers often hold deeply flawed mental models of the energy and climate systems. Here we describe a simulation role-playing game, World Energy, that provides an immersive learning experience in which participants can create their own path forward for global energy policy and learn about the impact of their policy choices on carbon dioxide emissions, temperature rise, energy supply mix, energy prices, and energy demand. The game puts players in the decision-making roles of advisors to the United Nations Sustainable Energy for All Initiative (drawn from international leaders from industry, governments, intergovernmental organizations, and citizens groups) and, using a state-of-the-art decision-support simulator, asks them to negotiate a plan for global energy policy. We use the En-ROADS (Energy Rapid Overview and Decision Support) simulator, which runs on a laptop computer in <0.1 sec. En-ROADS enables users to specify many factors, including R&D-driven cost reductions in fossil fuel-based, renewable, or carbon-neutral energy technologies; taxes and subsidies for different energy sources; performance standards and energy efficiency; emissions prices; policies to address other greenhouse gas emissions (e.g., methane, nitrous oxide, chlorofluorocarbons, etc.); and assumptions about GDP and population. In World Energy, participants must balance climate change mitigation goals with equity, prices and access to energy, and the political feasibility of policies. Initial results indicate participants gain insights into the dynamics of the energy and climate systems and greater understanding of the potential impacts policies.

  3. The second generation model of greenhouse gas emissions: background and initial development

    International Nuclear Information System (INIS)

    The analysis of greenhouse gas emissions has made enormous progress during the course of the past decade. We have progressed from the use of simple time-trend extrapolations to the analysis of emissions of several greenhouse gases with parallel but independent behavioral and optimization models of energy, manufacturing, agriculture, and land-use systems. But our ability to examine potential future scenarios of greenhouse gas emissions is limited because modeling tools adequate to the task of integrating analyses of technologies and human activities on a global scale with regional detail, including energy production and consumption, agriculture, manufacture, capital formation, and land-use, along with the interdependencies between these categories, do not yet exist. The first generation of models were specialty models which focused on a particular aspect of the emissions problem without regard to how that activity interacted with other human and natural activities. The natural science pertaining to greenhouse warming now emphasizes the variety of gases associated with potential changes in the radiative composition of the atmosphere: CO2, CH4, CO, N2O, NOx, SO2, VOC's, chlorofluorocarbons, (CFC's) and CFC substitutes. Human activities generating the emissions of these gases are interdependent; actions taken to limit emissions from one segment of the economy will affect other segments of the economy. Policy issues such as the recycling of revenues from a carbon tax, land-use changes due to to tree-planting to sequestrate carbon dioxide or extensive development of biomass energy resources, require a more comprehensive modeling approach in which the relationship between technology, institutions, land use, economics and human activity is explicitly represented. The purpose of this paper is to describe briefly the design of a model which is capable of addressing greenhouse gas emissions and the consequences of alternative policy options. 7 refs

  4. EPA proposes CFC alternatives policy, ozone levels drop

    International Nuclear Information System (INIS)

    The Environmental Protection Agency has proposed its Significant New Alternatives Policy (SNAP), under which EPA will manage use of chlorofluorocarbon (CFC) substitutes. EPA also proposed a preliminary list of acceptable and unacceptable uses of CFC substitutes. Under SNAP, manufacturers or importers must notify EPA of the intent to sell, use, or distribute substitutes 90 days before introducing them into interstate commerce, and provide EPA with health and safety studies. EPA will determine eligibility for specific uses based on flammability, chemical toxicity, costs, global warming potential, and environmental and occupational exposures. Hydrochlorofluorocarbon (HCFC)-141b was targeted by EPA for restrictions in some applications involving polyurethane foams and solvent systems. Acceptable HCFC-141b uses include foams for insulation and flotation rigid polyurethane. HCFC-141b makers say the rule making does not come as a surprise. Elf Atochem says it has been working with EPA on the alternatives policy for the past two years and has steered away from unacceptable uses. Allied-Signal also says it has considered the limitations. Even while EPA plotted the management of CFC substitutes, there was further bad news on the stratospheric ozone layer. Government scientists at the National Aeronautics and Space Administrations's (NASA) Goddard Space Flight Center (Greenbelt, MD) say global ozone levels were 2%-3% lower in the second half of 1992 than at any previous time and that mid-latitudes Northern Hemisphere levels dropped 13%-14% below normal in January. Separately, NASA and Jet Propulsion Laboratory researchers report satellite measurements finding chlorine monoxide-a key villain in ozone destruction-in alarmingly high levels in the Arctic stratosphere. The NSA/JPL measurements-which had not been done before-are open-quote very soberingclose quotes, says Joe Waters, a JPL scientist

  5. Calibration of a groundwater flow model with different tracer technologies

    International Nuclear Information System (INIS)

    Full text: This study developed a mechanism to calibrate a regional groundwater flow model for an aquifer system in central Mexico (Guanajuato) by residence time values of a set of different tracers. The used tracers were carbon-14, tritium, chlorofluorocarbons (CFCs), and sulfur hexafluoride (SF6). The applied program for the flow simulations was the modular finite-difference MODFLOW-2000, coupled to the transport model MODPATH. The local recharge estimates obtained from the chloride mass-balance method were regionalised by a Kriging method, whilst hydraulic conductivity values for each geological unit were interpreted from pumping test data. The flow simulation was considered in steady-state conditions (pre-development model). Since the flow domain was complicate and the number of grid cells large, an algebraic multigrid solver was applied rather than the classical iterative methods. The calibration process consisted in adjusting the hydraulic conductivity values until (a) the calculated head distribution matched the observed water level measurements, and (b) the flow balance is satisfied in the whole flow domain (mass balance) and in parts of the flow domain (zone budget), (c) the mean residence time values of carbon-14, tritium, CFCs, and SF6 matched the time of travel of corresponding particles in the flow domain. Since carbon-14 is known to be modified due to geochemical interactions with the aquifer material, a preceding correction by using the program PHREEQC was necessary to obtain reliable mean residence time values. Due to the low time resolution, the tracers for young groundwater (tritium, CFCs, SF6) could be applied in the flow simulation only to indicate if the groundwater is younger or older than 40 to 50 years. This calibration approach was not only useful to quantitatively describe the flow regime of an aquifer system, but also to make some observations to its vulnerability. Comments on the experience of the used tracer technologies in combination

  6. Isotope methods for management of shared aquifers in northern Africa.

    Science.gov (United States)

    Wallin, Bill; Gaye, Cheikh; Gourcy, Laurence; Aggarwal, Pradeep

    2005-01-01

    Access to fresh water is one of the major issues of northern and sub-Saharan Africa. The majority of the fresh water used for drinking and irrigation is obtained from large ground water basins where there is minor contemporary recharge and the aquifers cross national borders. These aquifers include the Nubian Aquifer System shared by Chad, Egypt, Libya, and Sudan; the Iullemeden Aquifer System, extending over Niger, Nigeria, Mali, Benin, and Algeria; and the Northwest Sahara Aquifer System shared by Algeria, Libya, and Tunisia. These resources are subject to increased exploitation and may be severely stressed if not managed properly as witnessed already by declining water levels. In order to make appropriate decisions for the sustainable management of these shared water resources, planners and managers in different countries need an improved knowledge base of hydrological information. Three technical cooperation projects related to aquifer systems will be implemented by the International Atomic Energy Agency, in collaboration with the United Nations Educational, Scientific and Cultural Organization and United Nations Development Programme/Global Environmental Facility. These projects focus on isotope hydrology studies to better quantify ground water recharge and dynamics. The multiple isotope approach combining commonly used isotopes 18O and 2H together with more recently developed techniques (chlorofluorocarbons, 36Cl, noble gases) will be applied to improve the conceptual model to study stratification and ground water flows. Moreover, the isotopes will be an important indicator of changes in the aquifer due to water abstraction, and therefore they will assist in the effort to establish a sustainable ground water management.

  7. 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.

  8. Application of environmental tracers to delineate recharge patterns and nitrate contamination in shallow groundwater around a river

    Science.gov (United States)

    Kaown, Dugin; Koh, Eunhee; Park, Byeong-Hak; Lee, Kang-Kun

    2016-04-01

    Hydrogeochemical data, stable isotopes, chlorofluorocarbon (CFCs) and 3H-3He in groundwater were applied to characterize residence time, recharge patterns and nitrate contamination of groundwater in a small agricultural area, Yangpyung, Korea. The study area is located around a river and the measured groundwater table ranges from 1.5 to 2.65 m during the year. Most residents in the study area practice agriculture and potato, strawberry, and cabbage are the typical vegetables grown. Vegetable fields are mostly located in the upgradient area of the study area while forest and residence areas are located in the downgradient area. A lot of chemical and organic fertilizers are applied in the upgradient area. The concentration of NO3-N in groundwater showed 9.8-83.7 mg/L in the upgradient area and 0.1-22.6 mg/L in the downgradient area in 2014. It is necessary to monitor groundwater recharge patterns and transport processes of nitrate to protect surface water around the study area. The values of δ18O and δD showed that groundwater is recharged mainly from summer precipitation. The apparent groundwater ages using 3H-3He and CFCs ranged from 13 to 27 years in the upgradient area and from 25 to 35 years in the downgradient area. The NO3-N in more recently recharged groundwater showed higher concentrations while the NO3-N in older groundwater showed low concentrations. Some shallow wells in the downgradient area showed similar apparent groundwater age with that of the river water indicating groundwater-surface water interactions. A conceptual model of groundwater-surface water interactions using stable isotopes, apparent 3H-3He and CFCs age in groundwater will be useful to understand the hydrological processes and nitrate contamination of the study area.

  9. Hydrogeologic setting, hydraulic properties, and ground-water flow at the O-Field area of Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Banks, W.S.; Smith, B.S.; Donnelly, C.A.

    1996-01-01

    The U.S. Army disposed chemical agents, laboratory materials, and unexploded ordnance at O-Field in the Edgewood area of Aberdeen Proving Ground, Maryland, from before World War II until at least the 1950's. Soil, ground water, surface water,and wetland sediments in the O-Field area were contaminated from the disposal activity. A ground-water-flow model of the O-Field area was constructed by the U.S. Geological Survey (USGS) in 1989 to simulate flow in the central and southern part of the Gunpowder Neck. The USGS began an additional study of the contamination in the O-Field area in cooperation with the U.S. Army in 1990 to (1) further define the hydrogeologic framework of the O-Field area, (2) characterize the hydraulic properties of the aquifers and confining units, and (3) define ground-water flow paths at O-Field based on the current data and simulations of ground-water flow. A water-table aquifer, an upper confining unit, and an upper confined aquifer comprise the shallow ground-water aquifer system of the O-Field area. A lower confining unit, through which ground-water movement is negligible, is considered a lower boundary to the shallow aquifer system. These units are all part of the Pleistocene Talbot Formation. The model developed in the previous study was redesigned using the data collected during this study and emphasized New O-Field. The current steady-state model was calibrated to water levels of June 1993. The rate of ground-water flow calculated by the model was approximately 0.48 feet per day (ft/d) and the rate determined from chlorofluorocarbon dates was approximately 0.39 ft/d.

  10. Rapid Reconnaissance Mapping of Volatile Organic Compounds by Photoionization Detection at the USGS Amargosa Desert Research Site

    Science.gov (United States)

    Thordsen, J. J.; Stonestrom, D. A.; Conaway, C. H.; Luo, W.; Baker, R. J.; Andraski, B. J.

    2015-12-01

    Two types of handheld photoionization detectors were evaluated in April 2015 for reconnaissance mapping of volatile organic compounds (VOCs) in the unsaturated zone surrounding legacy disposal trenches for commercial low-level radioactive waste near Beatty, Nevada (USA). This method is rapid and cost effective when compared to the more conventional procedure used ate the site, where VOCs are collected on sorbent cartridges in the field followed by thermal desorption, gas chromatographic separation, and quantitation by mass spectroscopy in the laboratory (TD-GC-MS analysis). Using the conventional method, more than sixty distinct compounds have been identified in the 110-m deep unsaturated zone vapor phase, and the changing nature of the VOC mix over a 15-yr timeframe has been recorded. Analyses to date have identified chlorofluorocarbons (CFCs), chlorinated ethenes, chlorinated ethanes, gasoline-range hydrocarbons, chloroform, and carbon tetrachloride as the main classes of VOCs present. The VOC plumes emanating from the various subgroups of trenches are characterized by different relative abundances of the compound classes, and total VOC concentrations that cover several orders of magnitude. One of the photoionization detectors, designed for industrial compliance testing, lacked sufficient dynamic range and sensitivity to be useful. The other, a wide range (1 ppb-20,000 ppm) research-grade instrument with a 10.6 eV photoionization detector (PID) lamp, produced promising results, detecting roughly half of the non-CFC VOCs present. The rapid and inexpensive photoionization method is envisioned as a screening tool to supplement, expedite, and direct the collection of additional samples for TD-GC-MS analyses at this and other VOC-contaminated sites.

  11. Early work on the stratospheric ozone depletion-CFC issue

    Science.gov (United States)

    Molina, M.

    2012-12-01

    I became involved with the atmospheric chemistry of chlorofluorocarbons (CFCs) shortly after joining Sherry Rowland's research group at the University of California, Irvine, in 1973. CFCs had been detected in the troposphere by James Lovelock in 1971, and the question we set out to answer was the fate of these compounds of industrial origin in the environment, as well as possibly identifying any consequences of their accumulation in the atmosphere. After examining many potential sinks for these compounds we realized that because of their unusual stability the most likely destruction process was photolysis in the stratosphere. I carried out measurements of the absorption spectra of these compounds in the near ultraviolet; previous work involved only spectra in the far ultraviolet, not relevant for atmospheric chemistry. The results indicated that photolysis would take place in the upper stratosphere. I subsequently carried out calculations using one-dimensional atmospheric models to estimate their atmospheric residence times, which turned out to be many decades. We realized that the chlorine atoms generated by photolysis of the CFCs would participate in a catalytic chain reaction that would efficiently destroy ozone. Furthermore, we estimated that the amount of CFCs produced industrially was comparable to the amount of nitric oxide produced naturally in the stratosphere by the decomposition of nitrous oxide; work by Paul Crutzen and Harold Johnston had indicated that the abundance of ozone in the stratosphere was controlled by nitric oxide. We then formulated the hypothesis that the continued release of CFCs to the environment posed a threat to the stability of the ozone layer, and published our results in the journal Nature in 1974. The publication was noticed almost exclusively by the community of experts in stratospheric chemistry, and hence Sherry Rowland and I decided at that time that it was our responsibility to communicate this finding to society at large

  12. Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2

    International Nuclear Information System (INIS)

    This chapter updates information taken from Chapters 3 to 6 of the IPCC Working Group I Third Assessment Report. It concerns itself with trends in forcing agents and their precursors since 1750, and estimates their contribution to the radiative forcing (RF) of the climate system. Discussion of the understanding of atmospheric composition changes is limited to explaining the trends in forcing agents and their precursors. Areas where significant developments have occurred since the TAR are highlighted. The chapter draws on various assessments since the TAR, in particular the 2002 World Meteorological Organization (WMO), United Nations Environment Programme (UNEP) Scientific Assessment of Ozone Depletion (2003) and the IPCC Technology and Economic Assessment Panel (TEAP) special report on Safeguarding the Ozone Layer and the Global Climate System (2005). The chapter assesses anthropogenic greenhouse gas changes, aerosol changes and their impact on clouds, aviation-induced contrails and cirrus changes, surface albedo changes and natural solar and volcanic mechanisms. The chapter reassesses the 'radiative forcing' concept (Sections 2.2 and 2.8), presents spatial and temporal patterns of RF, and examines the radiative energy budget changes at the surface. For the long-lived greenhouse gases (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluoro-carbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6), hereinafter collectively referred to as the LLGHGs; Section 2.3), the chapter makes use of new global measurement capabilities and combines long-term measurements from various networks to update trends through 2005. Compared to other RF agents, these trends are considerably better quantified; because of this, the chapter does not devote as much space to them as previous assessments (although the processes involved and the related budgets are further discussed in Sections 7.3 and 7

  13. Measurements of HFC-134a and HCFC-22 in groundwater and unsaturated-zone air: implications for HFCs and HCFCs as dating tracers

    Science.gov (United States)

    Haase, Karl B.; Busenberg, Eurybiades; Plummer, L. Niel; Casile, Gerolamo; Sanford, Ward E.

    2014-01-01

    A new analytical method using gas chromatography with an atomic emission detector (GC–AED) was developed for measurement of ambient concentrations of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in soil, air, and groundwater, with the goal of determining their utility as groundwater age tracers. The analytical detection limits of HCFC-22 (difluorochloromethane, CHClF2) and HFC-134a (1,2,2,2-tetrafluoroethane, C2H2F4) in 1 L groundwater samples are 4.3 × 10− 1 and 2.1 × 10− 1 pmol kg− 1, respectively, corresponding to equilibrium gas-phase mixing ratios of approximately 5–6 parts per trillion by volume (pptv). Under optimal conditions, post-1960 (HCFC-22) and post-1995 (HFC-134a) recharge could be identified using these tracers in stable, unmixed groundwater samples. Ambient concentrations of HCFC-22 and HFC-134a were measured in 50 groundwater samples from 27 locations in northern and western parts of Virginia, Tennessee, and North Carolina (USA), and 3 unsaturated-zone profiles were collected in northern Virginia. Mixing ratios of both HCFC-22 and HFC-134a decrease with depth in unsaturated-zone gas profiles with an accompanying increase in CO2 and loss of O2. Apparently, ambient concentrations of HCFC-22 and HFC-134a are readily consumed by methanotrophic bacteria under aerobic conditions in the unsaturated zone. The results of this study indicate that soils are a sink for these two greenhouse gases. These observations contradict the previously reported results from microcosm experiments that found that degradation was limited above-ambient HFC-134a. The groundwater HFC and HCFC concentrations were compared with concentrations of chlorofluorocarbons (CFCs, CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6). Nearly all samples had measured HCFC-22 or HFC-134a that were below concentrations predicted by the CFCs and SF6, with many samples showing a complete loss of HCFC-22 and HFC-134a. This study indicates that HCFC-22 and HFC-134

  14. Experimental determination of phase diagram and modeling: Application to refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Coquelet, Christophe; Richon, Dominique [MINES ParisTech, CEP/TEP - Centre Energetique et Procedes, 35 rue St Honore, 77305 Fontainebleau Cedex (France)

    2009-11-15

    Accurate knowledge of phase diagrams is an essential step for optimized chemical engineering design and effective solution of engineering-related problem. As an example of the use of phase diagrams we have selected a topic at global concern which arose upon the discovery of the ozone depletion. In 1987, the Montreal protocol prohibited world-wide use and production of ChloroFluoroCarbons (CFCs) and of HydroChloroFluoroCarbons (HCFCs), while HydroFluoroCarbons (HFCs) were proposed as alternative refrigerants. Thus, the need arose for information required in the optimization of refrigerant production processes, particularly in the field of phase equilibria. These data can provide better evaluation of refrigerant production processes, especially with the aim of reducing global warning effects. In this communication, we present VLE equipments and the obtained phase diagrams concerning several binary systems involving R32, R290, R116, R744, R116, R134a, R227ea and other refrigerants. Cubic equations of state combining with modern mixing rules based on Gibbs excess models are used for the determination of phase diagrams. (author) [French] La connaissance des diagrammes de phases est essentielle, en genie des procedes, pour permettre aux ingenieurs de determiner la meilleure facon de proceder afin de trouver les solutions les plus efficaces et les plus performantes. Comme exemple d'utilisation des diagrammes de phases nous avons choisi le sujet traitant du probleme mondial qui est survenu lorsque le trou dans la couche d'ozone a ete decouvert. Les ChloroFluoroCarbures (CFC's) et HydroChloroFluoroCarbures (HCFC's) ont ete bannis lors du protocole de Montreal en 1987 au profit des HydroFluoroCarbures (HFC's) proposes comme solutions alternatives. Ces derniers ont un pouvoir de rechauffement climatique non negligeable et il est necessaire de disposer du maximum d'informations pour l'optimisation de leurs procedes de fabrication. Nous

  15. A 17-year record of environmental tracers in spring discharge, Shenandoah National Park, Virginia, USA: use of climatic data and environmental conditions to interpret discharge, dissolved solutes, and tracer concentrations

    Science.gov (United States)

    Busenberg, Eurybiades; Plummer, L. Niel

    2014-01-01

    A 17-year record (1995–2012) of a suite of environmental tracer concentrations in discharge from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park (SNP), Virginia, USA, reveals patterns and trends that can be related to climatic and environmental conditions. These data include a 12-year time series of monthly sampling at five springs, with measurements of temperature, specific conductance, pH, and discharge recorded at 30-min intervals. The monthly measurements include age tracers (CFC-11, CFC-12, CFC-113, CFC-13, SF6, and SF5CF3), dissolved gases (N2, O2, Ar, CO2, and CH4), stable isotopes of water, and major and trace inorganic constituents. The chlorofluorocarbon (CFC) and sulfur hexafluoride (SF6) concentrations (in pptv) in spring discharge closely follow the concurrent monthly measurements of their atmospheric mixing ratios measured at the Air Monitoring Station at Big Meadows, SNP, indicating waters 0–3 years in age. A 2-year (2001–2003) record of unsaturated zone air displayed seasonal deviations from North American Air of ±10 % for CFC-11 and CFC-113, with excess CFC-11 and CFC-113 in peak summer and depletion in peak winter. The pattern in unsaturated zone soil CFCs is a function of gas solubility in soil water and seasonal unsaturated zone temperatures. Using the increase in the SF6 atmospheric mixing ratio, the apparent (piston flow) SF6 age of the water varied seasonally between about 0 (modern) in January and up to 3 years in July–August. The SF6 concentration and concentrations of dissolved solutes (SiO2, Ca2+, Mg2+, Na+, Cl−, and HCO3−) in spring discharge demonstrate a fraction of recent recharge following large precipitation events. The output of solutes in the discharge of springs minus the input from atmospheric deposition per hectare of watershed area (mol ha−1 a−1) were approximately twofold greater in watersheds draining the regolith of Catoctin metabasalts than that of granitic

  16. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2 from in situ and air archive observations

    Directory of Open Access Journals (Sweden)

    P. G. Simmonds

    2015-08-01

    Full Text Available High frequency, ground-based, in situ measurements from eleven globally-distributed sites covering 1994–2014, combined with measurements of archived air samples dating from 1978 onward and atmospheric transport models, have been used to estimate the growth of 1,1-difluoroethane (HFC-152a, CH3CHF2 mole fractions in the atmosphere and the global emissions required to derive the observed growth. HFC-152a is a significant greenhouse gas but since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs and hydrochlorofluorocarbons (HCFCs. HFC-152a has exhibited substantial atmospheric growth since the first measurements reaching a maximum annualised global growth rate of 0.81 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annualised rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an average rate of change in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The average Northern Hemisphere (NH mixing ratio in 1994 was 1.2 ppt rising to a mixing ratio of 10.2 ppt in December 2014. Average annual mixing ratios in the Southern Hemisphere (SH in 1994 and 2014 were 0.34 and 4.4 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mixing ratio enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia and Europe. Global HFC emissions (so called "bottom up" emissions reported by the United Nations Framework Convention on Climate Change (UNFCCC are based on cumulative national emission data reported to the UNFCCC, which in turn are based on national consumption data. There

  17. The NOAA Annual Greenhouse Gas Index - 2012 Update

    Science.gov (United States)

    Butler, J. H.; Montzka, S. A.; Conway, T. J.; Dlugokencky, E. J.; Elkins, J. W.; Masari, K. A.; Schnell, R. C.; Tans, P. P.

    2012-04-01

    contribution to radiative forcing. In this presentation, preliminary values for 2011 will be evaluated and discussed with respect to the contributions from CO2, CH4,nitrous oxide (N2O), chlorofluorocarbons (CFCs), and other emerging greenhouse gases.

  18. Evidence of CFC degradation in groundwater under pyrite-oxidizing conditions

    Science.gov (United States)

    Sebol, L.A.; Robertson, W.D.; Busenberg, E.; Plummer, L.N.; Ryan, M.C.; Schiff, S.L.

    2007-01-01

    A detailed local-scale monitoring network was used to assess CFC distribution in an unconfined sand aquifer in southwestern Ontario where the zone of 1-5-year-old groundwater was known with certainty because of prior use of a bromide tracer. Groundwater ???5 years old was confined to an aerobic zone at ???5 m depth and had CFC concentrations consistent with modern atmospheric mixing ratios at recharge temperatures of 7-11 ??C, as was observed in the 3-m thick vadose zone at the site. At depths below 6 m, the groundwater became progressively more reducing, however, with a denitrifying horizon at 6-7 m depth, and a Mn and Fe reducing zone below 7 m depth. In the anaerobic zone, 3H/3He ratios indicated that groundwater-age continued to increase uniformly with depth, to a maximum value of 27 years at 13 m depth. CFC concentrations, however, decreased abruptly within the denitrifying zone, leading to substantial age overestimation compared to the 3H/3He ages. Noble gas data indicated that the apparent CFC mass loss was not likely the result of gas stripping from possible bubble formation; thus, CFC degradation was indicated in the anoxic zone. The field data are consistent with first-order degradation rates of 0.3 yr-1 for CFC-12, 0.7 yr-1 for CFC-11, and 1.6 yr-1 for CFC-113. CFC attenuation at this site coincides with a zone where reduced S (pyrite) is actively oxidized by NO3 and dissolved oxygen (DO). Similar behavior has been observed at other sites [Tesoriero, A.J., Liebscher, H., Cox, S.E., 2000. Mechanism and rate of denitrification in an agricultural watershed: electron and mass balance along groundwater flow path. Water Resour. Res. 36 (6), 1545-1559; Hinsby, K., Hojberg, A.L., Engesgaard, P., Jensen, K.H., Larsen, F., Plummer, L.N., Busenberg, E., Accepted for publication. Transport and degradation of chlorofluorocarbons (CFCs) in a pyritic aquifer, Rabis Creek, Denmark. Water Resour. Res.], further demonstrating that the use of CFCs for age-dating anaerobic

  19. Seasonal variability in the Deep Western Boundary Current around the Eastern tip of Brazil

    Science.gov (United States)

    Rhein, Monika; Stramma, Lothar

    2005-08-01

    The spreading of recently ventilated North Atlantic Deep Water (NADW) from the formation region to the equatorial Atlantic occurs mainly in the Deep Western Boundary Current (DWBC). When crossing the equator between 44°W and 35°W, the DWBC is split in two velocity cores through a chain of seamounts around the Atoll das Rocas at 3.5°S. Further eastward the DWBC contributes to the zonally oriented equatorial current system. The circulation of the NADW in the crucial region around the eastern tip of Brazil is examined using 8 CTD and Chlorofluorocarbon (CFC) sections along 35°W and along 5°S, respectively, taken mainly in spring and fall in the years 1990-2002. As expected from the short direct flow path between the two sections, the CFC concentrations in the upper NADW (1400-2200 m) were similar at 35°W and 5°S during boreal autumn. In spring, however, a significant downstream CFC decrease was observed. If one attributes the decrease solely to the older age of water further downstream, the CFC concentration age difference between 35°W and 5°S in May 2002 would be 3-5 years. We interpret the aging to be caused by an eastward detour of the flow with the deep equatorial circulation before reaching 5°S in spring. Another conspicuous anomaly was found in the middle NADW (2200-3400 m) with downstream decreasing salinities in boreal spring, but not in autumn. This variability might also be caused by differences in the deep equatorial circulation, but in contrast to the uNADW, one cannot exclude enhanced mixing with water of South Atlantic origin in spring to be the cause of that variability. No seasonal difference was observed in the hydrography or the CFC concentrations for the lower NADW. The weaker CFC decrease along the equator compared with that in the DWBC downstream of 35°W, and the topographic features along the downstream path, point to a predominantly eastward flow of the deep lNADW core. The lNADW CFC core is no longer observed at 11°S. Repeated

  20. Short- and Medium-term Atmospheric Effects of Very Large Solar Proton Events

    Science.gov (United States)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Fleming, Eric L.; Labow, Gordon J.; Randall, Cora E.; Lopez-Puertas, Manuel; Funke, Bernd

    2007-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. In particular, the humankind or anthropogenic influence on ozone from chlorofluorocarbons and halons (chlorine and bromine) has led to international regulations greatly limiting the release of these substances. These anthropogenic effects on ozone are most important in polar regions and have been significant since the 1970s. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the short- and medium-term (days to a few months) influences of solar proton events between 1963 and 2005 on stratospheric ozone. The four largest events in the past 45 years (August 1972; October 1989; July 2000; and October-November 2003) caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen- containing compounds, which led to the polar ozone destruction. The hydrogen-containing compounds have very short lifetimes and lasted for only a few days (typically the duration of the solar proton event). On the other hand, the nitrogen-containing compounds lasted much longer, especially in the Winter. The nitrogen oxides were predicted

  1. Part A. The effect of the dimensions of learning model on the epistemological beliefs of students enrolled in general chemistry laboratory for post-baccalaureate pre-medical students, and, Part B. Environmental quality survey utilizing TRI Explorer and USGS water data and the analysis and characterization of particulate matter using scanning electron microscopy

    Science.gov (United States)

    Wallace, Darcie

    The first part of this dissertation deals with the dimension of learning model was developed by Robert Marzano in response to a comprehensive research and theory based framework on cognition and learning. The strategy forms a background that can be used in instruction, curriculum, and assessment. The experimental group was exposed to the model and the control group was exposed to normal instruction for three lab activities in a summer general chemistry laboratory. The students were assessed for content knowledge via review of pre-laboratory and post-laboratory questions and for attitudinal changes via the Epistemological Beliefs Assessment for Physical Science Students. The study indicates that there were no attitudinal changes between the two groups. On the other hand, the instructional model is a variable technique, and the experimental group performed better on the post laboratory questions. The second part of this dissertation presents the results of an environmental quality survey utilizing the Environmental Protection Agency's TRI Explorer database as well as the United States Geological Survey water quality database could provide a valuable tool for the assessment of land, air, and water contamination. The top three air, water, and land releases will be obtained from 1988 to 2002 for counties surrounding major cities in Tennessee. There was found to be a poor correlation between the TRI Explorer and USGS data for the counties in this study. This poor correlation may be due to the degradation pathways of the chemicals released. It should be noted that there has been a decrease in many of the compounds, such as chlorofluorocarbons, which have been addressed in legislation. Air samples were collected on mixed cellulose ester filters and silver membrane using a GS Cyclone particle size selector and analyzed using Scanning Electron Microscopy with Energy Dispersive X-ray Analysis. Unlike quartz filters, sample loss and change was minimal with the use of the mixed

  2. Watershed Influences on Residence Time and Oxygen Reduction Rates in an Agricultural Landscape

    Science.gov (United States)

    Shope, C. L.; Tesoriero, A. J.

    2015-12-01

    Agricultural use of synthetic fertilizers and animal manure has led to increased crop production, but also elevated nitrogen concentrations in groundwater, resulting in impaired water quality. Groundwater oxygen concentrations are a key indicator of potential biogeochemical processes, which control water/aquifer interactions and contaminant transport. The U.S. Geological Survey's National Water-Quality Assessment Program has a long-history of studying nutrient transport and processing across the United States and the Glacial Aquifer system in particular. A series of groundwater well networks in Eastern Wisconsin is being used to evaluate the distribution of redox reaction rates over a range of scales with a focus on dissolved O2 reduction rates. An analysis of these multi-scale networks elucidates the influence of explanatory variables (i.e.: soil type, land use classification) on reduction rates and redox reactions throughout the Fox-Wolf-Peshtigo watersheds. Multiple tracers including dissolved gasses, tritium, helium, chlorofluorocarbons, sulfur hexafluoride, and carbon-14 were used to estimate groundwater ages (0.8 to 61.2 yr) at over 300 locations. Our results indicate O2 reduction rates along a flowpath study area (1.2 km2) of 0.15 mg O2 L-1 yr-1 (0.12 to 0.18 mg O2 L-1 yr-1) up to 0.41 mg O2 L-1 yr-1 (0.23 to 0.89 mg O2 L-1 yr-1) for a larger scale land use study area (3,300 km2). Preliminary explanatory variables that can be used to describe the variability in reduction rates include soil type (hydrologic group, bulk density) and chemical concentrations (nitrite plus nitrate, silica). The median residence time expected to reach suboxic conditions (≤ 0.4 mg O2 L-1) for the flowpath and the land use study areas was 66 and 25 yr, respectively. These results can be used to elucidate and differentiate the impact of residence time on groundwater quality vulnerability and sustainability in agricultural regions without complex flow models.

  3. Italian WEEE management system and treatment of end-of-life cooling and freezing equipments for CFCs removal

    Energy Technology Data Exchange (ETDEWEB)

    Sansotera, M., E-mail: maurizio.sansotera@polimi.it [Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, via Mancinelli 7, I-20131 Milano (Italy); Istituto Nazionale di Scienza e Tecnologia dei Materiali (INSTM), via Giusti 9, I-50121 Firenze (Italy); Navarrini, W. [Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, via Mancinelli 7, I-20131 Milano (Italy); Istituto Nazionale di Scienza e Tecnologia dei Materiali (INSTM), via Giusti 9, I-50121 Firenze (Italy); Talaeemashhadi, S.; Venturini, F. [Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, via Mancinelli 7, I-20131 Milano (Italy)

    2013-06-15

    Highlights: • Italian data about WEEE management in the period 2005–2010 have been reported. • In 2001–2004 CFC release was monitored and Po Valley resulted as main source region. • The Italian directive on WEEE management was enacted in 2005 but took effect in 2008. • The CFC analytic procedures of the audit assessments have been discussed. - Abstract: This study presents and analyzes the data of the Italian system for take-back and recovery of waste electrical and electronic equipments (WEEEs) in the start-up period 2008–2010. The analysis was focused particularly on the data about the treatment of end-of-life cooling and freezing equipments. In fact, the wastes of cooling and freezing equipments have a high environmental impact. Indeed, in their compressor oil and insulation polyurethane (PU) foams chlorofluorocarbon (CFC) ozone-depleting gases are still present. In the period 2001–2004 Northern Italy resulted the main source in Europe of CFCs. The European Directive on WEEE management was enacted in 2002, but in Italy it was implemented by the legislative Decree in 2005 and it became operational in 2008. Actually, in 2008 the national WEEE Coordination Centre was founded in order to organize the WEEE pick-up process and to control collection, recovery and recycling targets. As a result, in 2010 the average WEEE collection per capita exceeded the threshold of more than 4 kg per inhabitant, as well as cooling and freezing appliances represented more than one fourth of the Italian WEEE collection stream. During the treatment of end-of-life cooling and freezing equipments, CFCs were recovered and disposed principally by burner methods. The analyses of defined specimens collected in the treatment facilities were standardized to reliably determine the amount of recovered CFCs. Samples of alkaline solid salt, alkaline saline solution, polyurethane matrix and compressor oil collected during the audit assessment procedure were analyzed and the results

  4. Italian WEEE management system and treatment of end-of-life cooling and freezing equipments for CFCs removal

    International Nuclear Information System (INIS)

    Highlights: • Italian data about WEEE management in the period 2005–2010 have been reported. • In 2001–2004 CFC release was monitored and Po Valley resulted as main source region. • The Italian directive on WEEE management was enacted in 2005 but took effect in 2008. • The CFC analytic procedures of the audit assessments have been discussed. - Abstract: This study presents and analyzes the data of the Italian system for take-back and recovery of waste electrical and electronic equipments (WEEEs) in the start-up period 2008–2010. The analysis was focused particularly on the data about the treatment of end-of-life cooling and freezing equipments. In fact, the wastes of cooling and freezing equipments have a high environmental impact. Indeed, in their compressor oil and insulation polyurethane (PU) foams chlorofluorocarbon (CFC) ozone-depleting gases are still present. In the period 2001–2004 Northern Italy resulted the main source in Europe of CFCs. The European Directive on WEEE management was enacted in 2002, but in Italy it was implemented by the legislative Decree in 2005 and it became operational in 2008. Actually, in 2008 the national WEEE Coordination Centre was founded in order to organize the WEEE pick-up process and to control collection, recovery and recycling targets. As a result, in 2010 the average WEEE collection per capita exceeded the threshold of more than 4 kg per inhabitant, as well as cooling and freezing appliances represented more than one fourth of the Italian WEEE collection stream. During the treatment of end-of-life cooling and freezing equipments, CFCs were recovered and disposed principally by burner methods. The analyses of defined specimens collected in the treatment facilities were standardized to reliably determine the amount of recovered CFCs. Samples of alkaline solid salt, alkaline saline solution, polyurethane matrix and compressor oil collected during the audit assessment procedure were analyzed and the results

  5. Volatile Release From The Siberian Traps Inferred From Melt Inclusions

    Science.gov (United States)

    Black, Benjamin A.; Elkins-Tanton, Linda T.; Rowe, Michael C.; Ukstins Peate, Ingrid

    2010-05-01

    concentrations in the range of one weight percent. Visscher et al. (2004) proposed that chlorofluorocarbon compounds (CFCs) may have played a major role in the terrestrial end-Permian extinction. These CFCs are powerful catalysts for the breakdown of ozone, a process which can expose the biosphere to increased ultraviolet radiation. Measurements of elevated chlorine and fluorine from the Siberian Traps may thus provide a concrete source for CFCs that could have triggered this kill mechanism.

  6. Dynamics and reactivity of trapped electrons on supported ice crystallites.

    Science.gov (United States)

    Stähler, Julia; Gahl, Cornelius; Wolf, Martin

    2012-01-17

    The solvation dynamics and reactivity of localized excess electrons in aqueous environments have attracted great attention in many areas of physics, chemistry, and biology. This manifold attraction results from the importance of water as a solvent in nature as well as from the key role of low-energy electrons in many chemical reactions. One prominent example is the electron-induced dissociation of chlorofluorocarbons (CFCs). Low-energy electrons are also critical in the radiation chemistry that occurs in nuclear reactors. Excess electrons in an aqueous environment are localized and stabilized by the local rearrangement of the surrounding water dipoles. Such solvated or hydrated electrons are known to play an important role in systems such as biochemical reactions and atmospheric chemistry. Despite numerous studies over many years, little is known about the microscopic details of these electron-induced chemical processes, and interest in the fundamental processes involved in the reactivity of trapped electrons continues. In this Account, we present a surface science study of the dynamics and reactivity of such localized low-energy electrons at D(2)O crystallites that are supported by a Ru(001) single crystal metal surface. This approach enables us to investigate the generation and relaxation dynamics as well as dissociative electron attachment (DEA) reaction of excess electrons under well-defined conditions. They are generated by photoexcitation in the metal template and transferred to trapping sites at the vacuum interface of crystalline D(2)O islands. In these traps, the electrons are effectively decoupled from the electronic states of the metal template, leading to extraordinarily long excited state lifetimes on the order of minutes. Using these long-lived, low-energy electrons, we study the DEA to CFCl(3) that is coadsorbed at very low concentrations (∼10(12) cm(-2)). Using rate equations and direct measurement of the change of surface dipole moment, we

  7. Global stratospheric chlorine inventories for 2004–2009 from Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS measurements

    Directory of Open Access Journals (Sweden)

    A. T. Brown

    2013-09-01

    Full Text Available We present chlorine budgets calculated between 2004 and 2009 for four latitude bands (70° N–30° N, 30° N–0° N, 0° N–30° S, and 30° S–70° S. The budgets were calculated using ACE-FTS version 3.0 retrievals of the volume mixing ratios (VMRs of 9 chlorine-containing species: CCl4, CFC-12 (CCl2F2, CFC-11 (CCl3F, COCl2, COClF, HCFC-22 (CHF2Cl, CH3Cl, HCl and ClONO2. These data were supplemented with calculated VMRs from the SLIMCAT 3-D chemical transport model (CFC-113, CFC-114, CFC-115, H-1211, H-1301, HCFC-141b, HCFC-142b, ClO and HOCl. The total chlorine profiles are dominated by chlorofluorocarbons (CFCs and halons up to 24 km in the tropics and 19 km in the extra-tropics. In this altitude range CFCs and halons account for 58% of the total chlorine VMR. Above this altitude HCl increasingly dominates the total chlorine profile, reaching a maximum of 95% of total chlorine at 54 km. All total chlorine profiles exhibit a positive slope with altitude, suggesting that the total chlorine VMR is now decreasing with time. This conclusion is supported by the time series of the mean stratospheric total chlorine budgets which show mean decreases in total stratospheric chlorine of 0.38 ± 0.03% per year in the Northern Hemisphere extra-tropics, 0.35 ± 0.07% per year in the Northern Hemisphere tropical stratosphere, 0.54 ± 0.16% per year in the Southern Hemisphere tropics and 0.53 ± 0.12% per year in the Southern Hemisphere extra-tropical stratosphere for 2004–2009. Globally stratospheric chlorine is decreasing by 0.46 ± 0.02% per year. Both global warming potential-weighted chlorine and ozone depletion potential-weighted chlorine are decreasing at all latitudes. These results show that the Montreal Protocol has had a significant effect in reducing emissions of both ozone-depleting substances and greenhouse gases.

  8. Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies

    Directory of Open Access Journals (Sweden)

    L. Hoffmann

    2014-06-01

    Full Text Available Chlorofluorocarbons (CFCs play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their global loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer-tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11 and CF2Cl2 (CFC-12. We present estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 yr for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS, the HIgh Resolution Dynamics Limb Sounder (HIRDLS, and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. We found a CFC-11/CFC-12 lifetime ratio of 0.47±0.08 and a CFC-12 lifetime of 111(96–132 yr for ACE-FTS, a ratio of 0.46±0.07 and a lifetime of 112(97–133 yr for HIRDLS, and a ratio of 0.46±0.08 and a lifetime of 112(96–135 yr for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.47±0.04 and the CFC-12 lifetime estimate is 112(102–123 yr. These results agree with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC reassessment, which recommends lifetimes of 52(43–67 yr and 102(88–122 yr, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled model we found a CFC-11/CFC-12 lifetime ratio of 0.48±0.07 and a CFC-12 lifetime of 110(95–129 yr, based on

  9. Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies

    Directory of Open Access Journals (Sweden)

    L. Hoffmann

    2014-11-01

    Full Text Available Chlorofluorocarbons (CFCs play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their stratospheric loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer–tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11 and CF2Cl2 (CFC-12. We present estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 years for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS, the HIgh Resolution Dynamics Limb Sounder (HIRDLS, and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. We found a CFC-11/CFC-12 lifetime ratio of 0.47±0.08 and a CFC-12 lifetime of 112(96–133 years for ACE-FTS, a ratio of 0.46±0.07 and a lifetime of 113(97–134 years for HIRDLS, and a ratio of 0.46±0.08 and a lifetime of 114(98–136 years for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.46±0.04 and the CFC-12 lifetime estimate is 113(103–124 years. These results agree with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC reassessment, which recommends lifetimes of 52(43–67 years and 102(88–122 years, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled model we found a CFC-11/CFC-12 lifetime ratio of 0.48±0.07 and a CFC-12 lifetime

  10. Anharmonic force field and vibrational dynamics of CH2F2 up to 5000 cm(-1) studied by Fourier transform infrared spectroscopy and state-of-the-art ab initio calculations.

    Science.gov (United States)

    Tasinato, Nicola; Regini, Giorgia; Stoppa, Paolo; Pietropolli Charmet, Andrea; Gambi, Alberto

    2012-06-01

    Difluoromethane (CH(2)F(2), HFC-32) is a molecule used in refrigerant mixtures as a replacement of the more environmentally hazardous, ozone depleting, chlorofluorocarbons. On the other hand, presenting strong vibration-rotation bands in the 9 μm atmospheric window, it is a greenhouse gas which contributes to global warming. In the present work, the vibrational and ro-vibrational properties of CH(2)F(2), providing basic data for its atmospheric modeling, are studied in detail by coupling medium resolution Fourier transform infrared spectroscopy to high-level electronic structure ab initio calculations. Experimentally a full quantum assignment and accurate integrated absorption cross sections are obtained up to 5000 cm(-1). Ab initio calculations are carried out by using CCSD(T) theory and large basis sets of either the correlation consistent or atomic natural orbital hierarchies. By using vibrational perturbation theory to second order a complete set of vibrational and ro-vibrational parameters is derived from the ab initio quartic anharmonic force fields, which well compares with the spectroscopic constants retrieved experimentally. An excellent agreement between theory and experiment is achieved for vibrational energy levels and integrated absorption cross sections: transition frequencies up to four quanta of vibrational excitation are reproduced with a root mean square deviation (RMSD) of 7 cm(-1) while intensities are predicted within few km mol(-1) from the experiment. Basis set performances and core correlation effects are discussed throughout the paper. Particular attention is focused in the understanding of the anharmonic couplings which rule the vibrational dynamics of the |ν(1)>, |2ν(8)>, |2ν(2)> three levels interacting system. The reliability of the potential energy and dipole moment surfaces in reproducing the vibrational eigenvalues and intensities as well as in modeling the vibrational and ro-vibrational mixings over the whole 400-5000 cm(-1

  11. Global and regional emission estimates for HCFC-22

    Directory of Open Access Journals (Sweden)

    E. Saikawa

    2012-11-01

    Full Text Available HCFC-22 (CHClF2, chlorodifluoromethane is an ozone-depleting substance (ODS as well as a significant greenhouse gas (GHG. HCFC-22 has been used widely as a refrigerant fluid in cooling and air-conditioning equipment since the 1960s, and it has also served as a traditional substitute for some chlorofluorocarbons (CFCs controlled under the Montreal Protocol. A low frequency record on tropospheric HCFC-22 since the late 1970s is available from measurements of the Southern Hemisphere Cape Grim Air Archive (CGAA and a few Northern Hemisphere air samples (mostly from Trinidad Head using the Advanced Global Atmospheric Gases Experiment (AGAGE instrumentation and calibrations. Since the 1990s high-frequency, high-precision, in situ HCFC-22 measurements have been collected at these AGAGE stations. Since 1992, the Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL has also collected flasks on a weekly basis from remote sites across the globe and analyzed them for a suite of halocarbons including HCFC-22. Additionally, since 2006 flasks have been collected approximately daily at a number of tower sites across the US and analyzed for halocarbons and other gases at NOAA. All results show an increase in the atmospheric mole fractions of HCFC-22, and recent data show a growth rate of approximately 4% per year, resulting in an increase in the background atmospheric mole fraction by a factor of 1.7 from 1995 to 2009. Using data on HCFC-22 consumption submitted to the United Nations Environment Programme (UNEP, as well as existing bottom-up emission estimates, we first create globally-gridded a priori HCFC-22 emissions over the 15 yr since 1995. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4, and a Bayesian inverse method to estimate global as well as regional annual emissions. Our inversion indicates

  12. Satellite observations of stratospheric hydrogen fluoride and comparisons with SLIMCAT calculations

    Science.gov (United States)

    Harrison, J. J.; Chipperfield, M. P.; Boone, C. D.; Dhomse, S. S.; Bernath, P. F.; Froidevaux, L.; Anderson, J.; Russell, J., III

    2015-12-01

    The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Many of these fluorine-containing species deplete stratospheric ozone, and are regulated by the Montreal Protocol. Once in the atmosphere they slowly degrade, ultimately leading to the formation of HF, the dominant reservoir of stratospheric fluorine due to its extreme stability. Monitoring the growth of stratospheric HF is therefore an important marker for the success of the Montreal Protocol. We report the comparison of global distributions and trends of HF measured in the Earth's atmosphere by the satellite remote-sensing instruments ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer), which has been recording atmospheric spectra since 2004, and HALOE (HALogen Occultation Experiment), which recorded atmospheric spectra between 1991 and 2005, with the output of SLIMCAT, a state-of-the-art three-dimensional chemical transport model. In general the agreement between observation and model is good, although the ACE-FTS measurements are biased high by ∼ 10 % relative to HALOE. The observed global HF trends reveal a substantial slowing down in the rate of increase of HF since the 1990s: 4.97 ± 0.12 % year-1 (1991-1997; HALOE), 1.12 ± 0.08 % year-1 (1998-2005; HALOE), and 0.52 ± 0.03 % year-1 (2004-2012; ACE-FTS). In comparison, SLIMCAT calculates trends of 4.01, 1.10, and 0.48 % year-1, respectively, for the same periods; the agreement is very good for all but the earlier of the two HALOE periods. Furthermore, the observations reveal variations in the HF trends with latitude and altitude, for example between 2004 and 2012 HF actually decreased in the Southern Hemisphere below ∼ 35 km. SLIMCAT calculations broadly agree with these observations, most notably between 2004 and 2012. Such variations are attributed to variability in stratospheric dynamics

  13. Stirring by deep cyclones and the evolution of Denmark strait overflow water observed at line W

    Science.gov (United States)

    Andres, M.; Toole, J. M.; Torres, D. J.; Smethie, W. M.; Joyce, T. M.; Curry, R. G.

    2016-03-01

    Shipboard velocity and water property data from 18 transects across the North Atlantic Deep Western Boundary Current (DWBC) near 40 °N are examined to study the evolution of the Denmark Strait Overflow Water (DSOW) component of the DWBC and mixing between DSOW and the interior. The examined transects along Line W - which stretches from the continental shelf south of New England to Bermuda - were made between 1994 and 2014. The shipboard data comprise measurements at regular stations of velocity from lowered acoustic Doppler current profilers, CTD profiles and trace gas chlorofluorocarbon (CFC) concentrations from bottle samples at discrete depths. Comparison of the Line W velocity sections with concurrent sea surface height maps from satellite altimetry indicates that large cyclones in the deep ocean accompany intermittent quasi-stationary meander troughs in the Gulf Stream path at Line W. A composite of 5 velocity sections along Line W suggests that a typical cyclone reaches swirl speeds of greater than 30 cm s-1 at 3400-m depth and has a radius (distance between the center and the maximum velocity) of 75 km. Tracer data suggest that these cyclones affect not only the deep velocity structure along Line W, but also provide a mechanism for water exchange between the DWBC's DSOW and the interior. Vigorous exchange is corroborated by a mismatch in the CFC-11:CFC-12 and CFC-113:CFC-12 ratio ages calculated for DSOW at Line W. During the most recent 5-year period (2010-2014), a decrease in DSOW density has been driven by warming (increasing by almost 0.1 °C) as salinity has increased only slightly (by 0.003, which is close to the 0.002 uncertainty of the measurements). The abyssal ocean offshore of the DWBC and Gulf Stream and deeper than 3000-m depth has freshened at a rate of 6×10-4 yr-1 since at least 2003. Density here remains nearly unchanged over this period, due to temperature compensation, though a linear cooling trend in the abyssal ocean (to compensate the

  14. Modeling of Reactive Transport of Nitrate in a Heterogeneous Alluvial Fan Aquifer, San Joaquin Valley, California

    Science.gov (United States)

    Green, C. T.; Phillips, S. P.

    2005-12-01

    Fate of nitrate in an alluvial fan aquifer in the San Joaquin Valley, California, was investigated with combined laboratory analyses, field measurements, geostatistics, and flow and reactive transport modeling. In the summer of 2003, groundwater wells and lysimeters were installed along a 1-km transect extending upgradient from the Merced River through an unfarmed riparian zone, a corn field, and an orchard. Groundwater levels have been monitored continuously. Saturated and unsaturated pore waters were analyzed quarterly for nutrients, anions, and cations. Sediment core samples from above and below the water table were analyzed for organic matter, nutrients, inorganic chemistry, and potential denitrification using denitrification enzyme assays (DEA's) based on the acetylene block technique. Curve fitting of DEA's provided core-scale estimates of microbial populations and growth coefficients. DEA biomass was similar to values obtained with the most probable number technique. Growth coefficients were found to be relatively uniform across the site, while biomass varied by several orders of magnitude. Age dates estimated from Chlorofluorocarbon (CFC) and Sulfur Hexafluoride (SF6), together with analyses of nitrogen species and excess nitrogen gas, provided approximate aquifer-scale, zero-order denitrification rates. The field and laboratory measurements served as input for geostatistical realizations of sediment properties and simulations of reactive transport of nitrate in the saturated zone. Analyses of cores, drillers' logs, and previous interpretations of the local geology were used to generate transition probability models of hydrofacies distributions within Holocene alluvium and pre-Holocene fans, and maps of the boundaries between these stratigraphic sequences. Multiple 3-D realizations were created and ranked based on lateral and vertical bulk-flow properties. For realizations representing a range of geological conditions, 3-D flow was computed with boundary

  15. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2) from in situ and air archive observations

    Science.gov (United States)

    Simmonds, P. G.; Rigby, M.; Manning, A. J.; Lunt, M. F.; O'Doherty, S.; McCulloch, A.; Fraser, P. J.; Henne, S.; Vollmer, M. K.; Mühle, J.; Weiss, R. F.; Salameh, P. K.; Young, D.; Reimann, S.; Wenger, A.; Arnold, T.; Harth, C. M.; Krummel, P. B.; Steele, L. P.; Dunse, B. L.; Miller, B. R.; Lunder, C. R.; Hermansen, O.; Schmidbauer, N.; Saito, T.; Yokouchi, Y.; Park, S.; Li, S.; Yao, B.; Zhou, L. X.; Arduini, J.; Maione, M.; Wang, R. H. J.; Ivy, D.; Prinn, R. G.

    2016-01-01

    High frequency, in situ observations from 11 globally distributed sites for the period 1994-2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2). These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr-1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr-1 in 2010 with a further decline to an annual average rate of growth in 2013-2014 of -0.06 ± 0.05 ppt yr-1. The annual average Northern Hemisphere (NH) mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH) in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr-1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr-1 in 2011, declining to 52.5 ± 20.1 Gg yr-1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr-1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called "bottom up" emissions) reported by the United Nations Framework Convention on Climate Change (UNFCCC) are based on cumulative national emission data reported to the UNFCCC, which in turn are based on

  16. The Long-term Middle Atmospheric Influence of Very Large Solar Proton Events

    Science.gov (United States)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Randall, Cora E.; Fleming, Eric L.; Frith, Stacey M.

    2008-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. The humankind or anthropogenic influence on ozone originates from the chlorofluorocarbons and halons (chlorine and bromine) and has led to international regulations greatly limiting the release of these substances. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the long-term (> few months) influences of solar proton events from 1963 through 2004 on stratospheric ozone and temperature. There were extremely large solar proton events in 1972, 1989,2000,2001, and 2003. These events caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen-containing compounds, which led to the polar ozone destruction. The nitrogen-containing compounds, called odd nitrogen, lasted much longer than the hydrogen-containing compounds and led to long-lived stratospheric impacts. An extremely active period for these events occurred in the five-year period, 2000- 2004, and caused increases in odd nitrogen which lasted for several months after individual events. Associated stratospheric ozone decreases of >lo% were calculated

  17. Unsaturated zone 14CO2: implications for groundwater dating

    Science.gov (United States)

    Wood, C.; Cook, P. G.; Harrington, G. A.; Meredith, K.; Kipfer, R.

    2013-12-01

    Quantitative interpretation of the carbon-14 activity (14C) of dissolved inorganic carbon (DIC) in groundwater requires an understanding of the various chemical and physical processes that can vary the initial 14C activity from that of the original atmospheric source (carbon dioxide, CO2). Such processes include radioactive decay, carbonate mineral dissolution, isotope exchange, decay of organic matter and molecular diffusion. Many geochemical correction models exist to account for some of these processes (e.g., Fontes and Garnier, 1979). However in most existing correction schemes, it is assumed that the 14C activity of CO2 in the unsaturated zone is in equilibrium with the atmosphere (i.e., 14C:12C is the same as the atmospheric ratio). This assumption is rarely tested and in several cases has been found to be inappropriate (eg. Bacon and Keller, 1998; Walvoord et al., 2005). Not accounting for the influence of unsaturated zone processes on 14C may lead to problems in determining residence time and estimating fluxes from measured 14C data in groundwater. In this study we examined carbon isotope processes in deep unsaturated zone profiles (up to 30m in depth) in arid central Australia. At five sites, multi-level samples of unsaturated zone gas and groundwater were collected for 14C analysis. Chlorofluorocarbon (CFC-11 and CFC-12) samples were also collected in unsaturated zone gas. At all sites we observed a decrease in the 14C activity of unsaturated zone gas with depth, from approximately 107 pmC near the ground surface to 50 - 80 pmC immediately above the water table. The measured 14C data was reproduced in a one-dimensional model using Hydrus, with CFC concentrations used to help constrain the gas transport parameters. Modelling showed that the decrease in 14C could be explained by CO2 production from different sources at different depths in the unsaturated zone (e.g. plant root respiration at shallower depths, oxidation of dead organic matter at greater

  18. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V John V. Vickers Cruise in the Pacific Ocean (WOCE Section P13, NOAA CGC92 Cruise, August 4 - October 21, 1992)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, A.

    2001-01-11

    This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) and total alkalinity (TALK) at hydrographic stations during the R/V John V. Vickers oceanographic cruise in the Pacific Ocean (Section P13). Conducted as part of the World Ocean Circulation Experiment (WOCE) and the National Oceanic and Atmospheric Administration's Climate and Global Change Program, the cruise began in Los Angeles, California, on August 4, 1992, with a transit line (Leg 0) to Dutch Harbor, Alaska. On August 16, the ship departed Dutch Harbor on Leg 1 of WOCE section P13. On September 15, the R/V John V. Vickers arrived in Kwajalein, Marshall Islands, for emergency repairs, and after 11 days in port departed for Leg 2 of Section P13 on September 26. The cruise ended on October 21 in Noumea, New Caledonia. Measurements made along WOCE Section P13 included pressure, temperature, salinity [measured by a conductivity, temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO{sub 2} , and TALK. The TCO{sub 2} was measured by coulometry using a Single-Operator Multiparameter Metabolic Analyzer (SOMMA). The overall precision and accuracy of the analyses was {+-}2 {micro}mol/kg. Samples collected for TALK were measured by potentiometric titration; precision was {+-}2 {micro}mol/kg. The CO{sub 2} -related measurements aboard the R/V John V. Vickers were supported by the U.S. Department of Energy. The WOCE Section P13 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of two oceanographic data files, two FORTRAN 90 data-retrieval routine files, a documentation file, and this printed report, which describes the contents and format of all files as well as the procedures and methods used to obtain the data. Instructions on how to access the data are provided.

  19. Collection of Arctic Ocean Data from US Navy Submarines on the New SCICEX Program

    Science.gov (United States)

    Smethie, W. M.; Sambrotto, R.; Boyd, T.; Richter-Menge, J.; Corbett, J.

    2011-12-01

    The SCICEX submarine Arctic science program originated in the 1990s when six dedicated science cruises were conducted in the Arctic Ocean aboard US Navy Sturgeon class submarines. After the cold war era Sturgeon class submarines were retired, several Science Accommodation cruises, for which a few days for scientific measurements were added to planned submarine transits through the Arctic Ocean, were carried out when opportunities arose. Renewed interest in conducting further Science Accommodation cruises on a regular basis to better document and understand how the Arctic Ocean responds to climate change resulted in publication of a scientific plan in 2010 (http://www.arctic.gov/publications/scicex_plan.pdf). In the spring of 2011 testing of data collection and water sampling methods aboard newer Virginia and Seawolf class submarines on transit from a Navy ice camp in the Beaufort Sea, was conducted in order to develop protocols and evaluate techniques. Ice draft measurements were also taken in the vicinity of the ice camp and near the North Pole to evaluate new data collection systems. This evaluation will include a comparison of the ice draft data with a comprehensive set of in situ ice thickness measurements taken near the ice camp. Under-ice submarine-launched eXpendable Condutivity Temperature Depth (XCTD) probes were deployed from the USS Connecticut (SSN-22), a Seawolf class submarine, and the resulting profiles compared to CTD casts from the APLIS ice station and historical profiles. Water samples were collected through the hull for measurements of tritium, helium isotopes, oxygen isotopes, chlorofluorocarbons, sulfur hexafluoride, nutrients, dissolved organic carbon, bacterioplankton, phytoplankton and particulates levels. These samples were returned to Lamont-Doherty Earth Observatory and were in the process of being measured at the time this abstract was written. Measurements completed at this time indicate good samples can be collected for CFC-12

  20. Wes Jackson. In nature's way.

    Science.gov (United States)

    1992-09-01

    The opinions and a biographical sketch of Wes Jackson, the founder of the Land Institute, are presented. The land Institute near Salina, Kansas is a nonprofit organization devoted to sustainable agriculture. Opinions are provided on the relationship of the Land Institute to sustainable agriculture, the definition of sustainability, the feasibility of replication of his work, his ideas about the destruction wreaked by the plow vs. the sword, technology and population growth, the future farmer, and the speed with which modern science has destroyed the ozone layer. Sustainable agriculture is using the prairie to provide answers to how agriculture can work with nature; the approach will take longer but will sustain both agriculture and people for another 10,000 years. The system runs on sunlight and recycles all materials and is based on the principles of ecosystems, which have been around for hundreds of years. Agricultural technology is based on a fossil fuel intensive infrastructure and is "parachuted into Third World countries." "Corn - the gift of the gods has been the killer of this continent." 50% of the topsoil has been lost, and soil is more important than oil. Advances in biotechnology are seen as the "human cleverness" approach; the preference is for an ecological approach first. Biotechnology tells how to "spin wheels faster," but it also generates more waste. The future farmer is more like the 19th century British naturalist. A projection is that 1st the oil is used up, then the natural gas, and when nuclear power is embraced, Murphy's Law must be repealed. It is important to understand the "we can'ts". Realization of limits will direct energy to the sun's potential and recycling and the flow of energy. Descartes' notion of correctable ignorance must be repudiated. Our knowledge-based world has led to acid rain, global warming, the ozone hole, and Chernobyl. It took just 25 years for chlorofluorocarbons to destroy the ozone layer. A philosophical shift in

  1. Determination of a wide range of volatile organic compounds in ambient air using multisorbent adsorption/thermal desorption and gas chromatography/mass spectrometry

    Science.gov (United States)

    Pankow, J.F.; Luo, W.; Isabelle, L.M.; Bender, D.A.; Baker, R.J.

    1998-01-01

    Adsorption/thermal desorption with multisorbent air-sampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3- trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02-0.06 ppbv. No breakthrough was detected with the prescribed sample volumes. Analyte stability on the cartridges was very good. Excellent recoveries were obtained with independent check standards. Travel spike recoveries ranged from 90 to 110% for 72 of the 87 compounds. The recoveries were less than 70% for bromomethane and chloroethene and for a few compounds such as methyl acetate that are subject to losses by hydrolysis; the lowest travel spike recovery was obtained for bromomethane (62%). Blank values for all compounds were either below detection or very low. Ambient atmospheric sampling was conducted in New Jersey from April to December, 1997. Three sites characterized by low, moderate, and high densities of urbanization/traffic were sampled. The median detected concentrations of the compounds were either similar at all three sites (as with the chlorofluorocarbon compounds) or increased with the density of urbanization/traffic (as with dichloromethane, MTBE, benzene, and toluene). For toluene, the median detected

  2. Trends of HCl, ClONO 2 and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden in comparison with KASIMA model calculations

    Directory of Open Access Journals (Sweden)

    U. Raffalski

    2011-01-01

    Full Text Available Trends of hydrogen chloride (HCl, chlorine nitrate (ClONO2 and hydrogen fluoride (HF column abundances above Kiruna (Northern Sweden, 67.84° N, 20.41° E derived from nearly 14 years (1996–2009 of measurement and model data are presented. The measurements have been performed with a Bruker 120 HR (later Bruker 125 HR Fourier transform infrared (FTIR spectrometer and the model used was KASIMA (KArlsruhe SImulation model of the Middle Atmosphere. To calculate the long-term trends, a linear function combined with an annual cycle was fitted to the data using a least squares method. The precision of the resulting trends was estimated with the so-called bootstrap resampling method. The relative trends were calculated on the basis of the linear fit result on 1 January 2000, 12:00 UTC. For hydrogen fluoride, both model and measurements show a positive trend that seems to decrease in the last few years. This suggests a stabilisation of the HF total column abundance. For the summer data (August to November, the FTIR trend of (+1.25 ± 0.28%/yr agrees within errors with the KASIMA one of (+1.55 ± 0.11%/yr. The trends determined for HCl and ClONO2 are significantly negative over the time period considered here. This corresponds to the expectations because the emission of their precursors (chlorofluorocarbons and hydrochlorofluorocarbons has been restricted in the Montreal Protocol in 1987 and its amendments and adjustments. The relative trend for ClONO2 from the FTIR measurements amounts to (−3.28 ± 0.56%/yr and the one for HCl to (−0.81± 0.23%/yr. KASIMA simulates a weaker decrease: For ClONO2, the result is (−0.90 ± 0.10%/yr and for HCl (−0.17± 0.06%/yr. Part of the difference between measurement and model data can be explained by sampling and the stronger annual cycle indicated by the measurements. There is a factor of about four between the trends of HCl and ClONO2 above Kiruna for both measurement and model data. The absolute values of

  3. Observed and simulated time evolution of HCl, ClONO2, and HF total column abundances

    Directory of Open Access Journals (Sweden)

    B.-M. Sinnhuber

    2011-12-01

    Full Text Available Time series of total column abundances of hydrogen chloride (HCl, chlorine nitrate (ClONO2, and hydrogen fluoride (HF were determined from ground-based Fourier transform infrared (FTIR spectra recorded at 17 sites belonging to the Network for the Detection of Atmospheric Composition Change (NDACC and located between 80.05° N and 77.82° S. These measurements are compared with calculations from five different models: the two-dimensional Bremen model, the two chemistry-transport models KASIMA and SLIMCAT, and the two chemistry-climate models EMAC and SOCOL. The overall agreement between the measurements and models for the total column abundances and the seasonal cycles is good. Trends of HCl, ClONO2, and HF are calculated from both measurement and model time series data, with a focus on the time range 2000–2009. Their precision is estimated with the bootstrap resampling method. The sensitivity of the trend results with respect to the fitting function, the time of year chosen and time series length is investigated, as well as a bias due to the irregular sampling of the measurements. For the two chlorine species, a decrease is expected during this period because the emission of their prominent anthropogenic source gases (solvents, chlorofluorocarbons (CFCs was restricted by the Montreal Protocol 1987 and its amendments and adjustments. As most of the restricted source gases also contain fluorine, the HF total column abundance was also influenced by the above-mentioned regulations in the time period considered. The measurements and model results investigated here agree qualitatively on a decrease of the chlorine species by around −1 % yr−1. The models simulate an increase of HF of around +1 % yr−1. This also agrees well with most of the measurements, but some of the FTIR series in the Northern Hemisphere show a stabilisation or even a decrease in the last few years. In general, for all three gases, the measured trends vary more strongly with

  4. Interaction between the geothermal outflow of southern Negros geothermal field and the shallow groundwater aquifer in Dumaguete City, Negros Oriental, Philippines

    International Nuclear Information System (INIS)

    Full text: Chemical and isotopic data indicate that significant quantity of mineralized thermal fluids are present downstream of the Palinpinon thermal spring areas that are naturally migrating into the shallow groundwater aquifer. Water district wells 49, 53, 54 and 55 located east from the Palinpinon springs, are tapping fluids that are relatively enriched in Na, K, Cl, SO4, B and Li ions. Fluids appear to be diluted towards the Sibulan area as waters become diluted to Ca+Mg-Cl+SO4 type. Shallow water southeast from the Palinpinon hot springs in the area of well 47 is composed of typical Ca+Mg-HCO3 groundwater. Isotopically, the shallow groundwater in the vicinity of well 54 is relatively enriched in δ18O and δ2H while in the well 47 area the waters are relatively depleted. Isotopic dilution lines reveal that well 55, which is receiving groundwater recharged at relatively lower elevations, mixes with thermal waters from springs Pal3 and 40. The other wells 49, 53 and 54 are being recharged by groundwater at relatively the same elevation, and this groundwater mixes with the other Palinpinon hot springs resulting to the enrichment of heavy isotopes. Slight variations in the stable isotope composition of the shallow groundwater were observed from 1999 to 2002, but the difference is not as distinct as the variations of the heavy isotopes in rainfall. Isotopic altitude gradient for δ18O and δ2H are 0.28 and 2.1 per mille per 100 meters change in elevation, respectively. These correspond to a calculated recharge elevation of at least 1000masl for the shallow groundwater. Relative age dating using chlorofluorocarbon (CFC) reveals relative ages from 10 to older than 60 years old, which partly confirm the previous Tritium age of 50 to 100 years old. Numerical simulation models confirm the migration of the thermal fluids from Palinpinon hot springs to the groundwater wells in the vicinity of well 54. Seasonal variation in isotope, Cl and SO4 concentration indicate only

  5. The 2003 edition of geisa: a spectroscopic database system for the second generation vertical sounders radiance simulation

    Science.gov (United States)

    Jacquinet-Husson, N.; Lmd Team

    The GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) computer accessible database system, in its former 1997 and 2001 versions, has been updated in 2003 (GEISA-03). It is developed by the ARA (Atmospheric Radiation Analysis) group at LMD (Laboratoire de Météorologie Dynamique, France) since 1974. This early effort implemented the so-called `` line-by-line and layer-by-layer '' approach for forward radiative transfer modelling action. The GEISA 2003 system comprises three databases with their associated management softwares: a database of spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located in a spectral range from the microwave to the limit of the visible. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the Giant Planets. a database of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. a database of refractive indices of basic atmospheric aerosol components. Illustrations will be given of GEISA-03, data archiving method, contents, management softwares and Web access facilities at: http://ara.lmd.polytechnique.fr The performance of instruments like AIRS (Atmospheric Infrared Sounder; http://www-airs.jpl.nasa.gov) in the USA, and IASI (Infrared Atmospheric Sounding Interferometer; http://smsc.cnes.fr/IASI/index.htm) in Europe, which have a better vertical resolution and accuracy, compared to the presently existing satellite infrared vertical sounders, is directly related to the quality of the spectroscopic parameters of the optically active gases, since these are essential input in the forward models used to simulate recorded radiance spectra. For these upcoming atmospheric sounders, the so-called GEISA/IASI sub-database system has been elaborated

  6. Ultraviolet radiation and plants: burning questions

    International Nuclear Information System (INIS)

    Plants use sunlight for photosynthesis and, as a consequence, are exposed to the ultraviolet (UV) radiation that is present in sunlight. UV radiation is generally divided into three classes: UV-C, UV-6, and UV-A. The UV-C region of the UV spectrum includes wavelengths below 280 nm; these highly energetic wavelengths are effectively absorbed by ozone in the stratosphere and, thus, are not present in sunlight at the earth’s surface. UV-C wavelengths will be removed from the light reaching the earth’s surface’so long as there is any ozone present (Caldwell et al., 1989). In contrast, UV radiation in the UV-B region, from 280 to 320 nm, does reach ground level. The UV-B portion of sunlight has received much attention in recent years because irradiation from this spectral region (especially 297 to 310 nm) will increase as the stratospheric ozone concentration decreases (Caldwell et al., 1989). Currently, ozone decreases result from chlorofluorocarbon contamination of the stratosphere (McFarland and Kaye, 1992). UV wavelengths from 320 to 390 nm, which make up the UV-A region of the spectrum, are not attenuated by ozone, so their fluence will be unaffected by ozone layer reduction. Like all living organisms, plants sense and respond to UV radiation, both the wavelengths present in sunlight (UV-A and UV-B) and the wavelengths below 280 nm (UV-C). AI1 types of UV radiation are known to damage various plant processes. Such damage can be classified into two categories: damage to DNA (which can cause heritable mutations) and damage to physiological processes. There has been much speculation about how increased UV radiation exposure will affect plants, but as yet, there are no definitive answers. In this review, I will discuss the kinds of damage that UV radiation can inflict on plants, the mechanisms plants use to perceive and respond to UV radiation, and the ecological relevance of UV light wavelengths that have been used in the experimental analysis of plant responses

  7. Monitoring of Observation Errors in the Assimilation of Satellite Ozone Data

    Science.gov (United States)

    Stajner, Ivanka; Winslow, Nathan; Rood, Richard B.; Pawson, Steven

    2003-01-01

    The stratospheric ozone layer protects life on Earth from the harmful effects of solar ultravioiet radiation. The ozone layer is currently in a fragile state because of depletion caused by man-made chemicals, especially chlorofluorocarbons. The state of the ozone layer is being monitored and evaluated by scientific experts around the world, in order to help policy makers assess the impacts of international protocols that control the production and release of ozone depleting chemicals. Scientists use a variety ozone measurements and models in order to form a comprehensive picture about the current state of the ozone layer, and to predict the future behavior (expected to be a recovery, as the abundance of the depleting chemicals decreases). Among the data sets used, those from satellite-borne instruments have the advantage of providing a wealth of information about the ozone distribution over most of the globe. Several instruments onboard American and international satellites make measurements of the properties of the atmosphere, from which atmospheric ozone amounts are estimated; long-term measurement programs enable monitoring of trends in ozone. However, the characteristics of satellite instruments change in time. For example, the instrument lenses through which measurements are made may deteriorate over time, or the satellite orbit may drift so that measurements over each location are made later and later in the day. These changes may increase the errors in the retrieved ozone amounts, and degrade the quality of estimated ozone amounts and of their variability. Our work focuses on combining the satellite ozone data with global models that capture atmospheric motion and ozone chemistry, using advanced statistical techniques: this is known as data assimilation. Our method provides a three-dimensional global ozone distribution that is consistent with both the satellite measurements and with our understanding of processes (described in the models) that control ozone

  8. THE OPPORTUNITY TO ADDRESS THE SUSTAINABLE INDUSTRIAL DEVELOPMENT IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Duduială Popescu Lorena

    2015-06-01

    Full Text Available Its economy experienced a sharp decline, coupled with a process of deindustrialization, projected on a phase of the property. In these circumstances, to discuss the sustainable development may seem inappropriate; therefore, be taken in steps such as halting the decline of the economy and industry; the industry revitalization and growth; the development that takes place according to the criteria of sustainable development. To this must be stopped declining industrial output and output stabilization. It must be found and made the necessary conditions leading to full use of the potential of the country, to stimulate those structural changes that allow the country to fall market economy conditions. To address the main criteria for sustainable industrial development since this time of economic downturn may be several reasons such as the need to respect the provisions of international treaties to which Romania is a party. Some of them may be mentioned as: putting control of Earth's greenhouse effect, preventing damage to the ozone layer (waiving of manufacture and use of chlorofluorocarbons, transboundary pollution and protection of large water basins of the border. Each of these treaties contain provisions that are converging concept of sustainable development. The entry into the European Union implies aligning Romanian legislation in the EU The EU Council adopted a common position, relative to a plan of action intended to give a new political impetus of the fifth environmental action program. The main objective of this program is the promotion of sustainable development throughout the economy. The Action Plan identifies priority areas for action, namely: • better integration of environmental issues into policies as those of agriculture, transport, energy, industry and tourism; • further development of basic tools acting on the market and, in particular, horizontal instruments; • improving enforcement and implementation of environmental

  9. Consistent sets of atmospheric lifetimes and radiative forcings on climate for CFC replacements: HCFCs and HFCs

    Science.gov (United States)

    Naik, Vaishali; Jain, Atul K.; Patten, Kenneth O.; Wuebbles, Donald J.

    2000-03-01

    Recognition of deleterious effects of chlorine and bromine on ozone and climate over the last several decades has resulted in international accords to halt the production of chlorine-containing chlorofluorocarbons (CFCs) and bromine-containing halons. It is well recognized, however, that these chemicals have had important uses to society, particularly as refrigerants, as solvents, as plastic blowing agents, as fire retardants and as aerosol propellants. This has led to an extensive search for substitute chemicals with appropriate properties to be used in place of the CFCs and halons. The purpose of this study is to evaluate in a consistent manner the atmospheric lifetime and radiative forcing on climate for a number of replacement compounds. The unique aspect of this study is its attempt to resolve inconsistencies in previous evaluations of atmospheric lifetimes and radiative forcings for these compounds by adopting a uniform approach. Using the latest version of our two-dimensional chemical-radiative-transport model of the global atmosphere, we have determined the atmospheric lifetimes of 28 hydrohalocarbons (HCFCs and HFCs). Through the comparison of the model-calculated lifetimes with lifetimes derived using a simple scaling method, our study adds to earlier findings that consideration of stratospheric losses is important in determining the lifetimes of gases. Discrepancies were found in the reported lifetimes of several replacement compounds reported in the international assessment of stratospheric ozone published by the World Meteorological Organization [Granier et al., 1999] and have been resolved. We have also derived the adjusted and instantaneous radiative forcings for CFC-11 and 20 other halocarbons using our radiative transfer model. The sensitivity of radiative forcings to the vertical distribution of these gases is investigated in this study and is shown to be significant. The difference in the global radiative forcing arising from the assumption of a

  10. Tropospheric halocompounds and nitrous oxide monitored at a remote site in the Mediterranean

    Science.gov (United States)

    Artuso, F.; Chamard, P.; Chiavarini, S.; di Sarra, A.; Meloni, D.; Piacentino, S.; Sferlazzo, M. D.

    2010-12-01

    Analysis of time series and trends of nitrous oxide (N 2O) and halocompounds weekly monitored at the Mediterranean island of Lampedusa are discussed. Atmospheric N 2O levels showed a linear upward growth rate of 0.78 ppb yr -1 and mixing ratios comparable with Northern Hemisphere global stations. CFC-11 and CFC-12 time series displayed a decline consistent with their phase-out. Chlorofluorocarbons (CFCs) replacing compounds and SF 6 exhibited an increasing temporal behaviour. The most rapid growth rate was recorded for HFC-134a with a value of 9.6% yr -1. The industrial solvents CCl 4 and CH 3CCl 3, banned by the Montreal Protocol, showed opposite trends. While CH 3CCl 3 reported an expected decay of -1.8 ppt yr -1, an increasing rate of 5.7 ppt yr -1 was recorded for CCl 4 and it is probably related to its relatively long lifetime and persisting emissions. Chlorinated halomethanes showed seasonality with a maximum in early April and a minimum at the end of September. Halon-1301 and Halon-1211 displayed a decreasing trend consistent with industry emission estimates. An interspecies correlation analysis gave positive high correlations between HCFC-22 and HFC-134a (+0.84) highlighting the common extensive employment as refrigerants. Sharing sources inferred the high coupling between CH 3Cl and CH 3Br (+0.73) and between CHCl 3 and CH 2Cl 2 (+0.77). A singular strong relationship (+0.55) between HFC-134a and CH 3I suggested the influence of an unknown anthropogenic source of CH 3I. Constraining of source and sink distribution was carried out by transport studies. Results were compared with the European Environment Agency (EEA) emission database. In contrast with the emission database results, our back trajectory analysis highlighted the release of large amounts of HFC-134a and SF 6 from Eastern Europe. Observations also showed that African SF 6 emissions may be considerable. Leakages from SF 6 insulated electrical equipments located in the industrialized Northern

  11. Final report for the IAEA urban aquifers RCA : determining the effects of storm water infiltration on groundwater quality in an urban fractured rock aquifer, Auckland, New Zealand

    International Nuclear Information System (INIS)

    Disposal of storm water in the Mt Eden-Mt Albert area of Auckland, New Zealand, is via ''soak holes'' drilled directly into the top of the fractured basalt. These soak holes receive storm water and sediment runoff from city streets throughout Mt Eden. Although this method of disposal has been used for at least 60 years, its sustainability with respect to groundwater quality has not been addressed. This study aimed to determine the impact of soakage on the chemical and isotopic composition of the groundwater. In addition, sediments captured by the soak holes were analysed to determine their effectiveness at trapping contaminants. Groundwater samples were collected between August 1998 and August 1999. Three sampling trips were carried out after rainfall events in October 1998, April 1999 and August 1999. Samples were analysed for major and trace components, including nutrients, dissolved and total heavy metals (As, Cr, Cu, Zn, Pb, Cd, and Ni), polynuclear aromatic hydrocarbons (PAHs), chlorofluorocarbons (CFCs) and stable and radiogenic isotopes. Cores of sediment collected in the soak holes were analysed for major components, total and leachable heavy metals, and PAHs to determine the ability of the sediments to adsorp contaminants. In summary, the Mt Eden aquifer system shows the effect of storm water infiltration rapidly after a rainfall event in some parts of the aquifer. Water quality has been effected in some areas, but in general the water quality is quite good considering the quantity of storm water discharge that has occurred in the area for the past 60 years. The relatively high quality of the water in the wells monitored may be attributed to the ability of the accumulated sediment in the soak holes and the aquifer fractures to trap contaminants. Further research is needed to determine if continued use of the groundwater system as a conduit for storm water infiltration will lead to clogging of the fractures in the aquifer and/or transport of particulates

  12. Measurement and prediction of enteric methane emission.

    Science.gov (United States)

    Sejian, Veerasamy; Lal, Rattan; Lakritz, Jeffrey; Ezeji, Thaddeus

    2011-01-01

    The greenhouse gas (GHG) emissions from the agricultural sector account for about 25.5% of total global anthropogenic emission. While CO(2) receives the most attention as a factor relative to global warming, CH(4), N(2)O and chlorofluorocarbons (CFCs) also cause significant radiative forcing. With the relative global warming potential of 25 compared with CO(2), CH(4) is one of the most important GHGs. This article reviews the prediction models, estimation methodology and strategies for reducing enteric CH(4) emissions. Emission of CH(4) in ruminants differs among developed and developing countries, depending on factors like animal species, breed, pH of rumen fluid, ratio of acetate:propionate, methanogen population, composition of diet and amount of concentrate fed. Among the ruminant animals, cattle contribute the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. The estimated CH(4) emission rate per cattle, buffaloe, sheep and goat in developed countries are 150.7, 137, 21.9 and 13.7 (g/animal/day) respectively. However, the estimated rates in developing countries are significantly lower at 95.9 and 13.7 (g/animal/day) per cattle and sheep, respectively. There exists a strong interest in developing new and improving the existing CH(4) prediction models to identify mitigation strategies for reducing the overall CH(4) emissions. A synthesis of the available literature suggests that the mechanistic models are superior to empirical models in accurately predicting the CH(4) emission from dairy farms. The latest development in prediction model is the integrated farm system model which is a process-based whole-farm simulation technique. Several techniques are used to quantify enteric CH(4) emissions starting from whole animal chambers to sulfur hexafluoride (SF6) tracer techniques. The latest technology developed to estimate CH(4) more accurately is the micrometeorological mass difference technique. Because

  13. Volatile Organic Compounds (VOCs) and Elevated Concentrations of Carbon Dioxide (CO2) in Unsaturated-Zone Vapors Near a Chemical and Low-Level Radioactivity Waste-Disposal Facility, Amargosa Desert Research Site, Nye County, Nevada

    Science.gov (United States)

    Baker, R. J.; Andraski, B. J.; Walvoord, M. A.; Stonestrom, D. A.; Prudic, D. E.; Luo, W.

    2003-12-01

    As part of its Toxic Substances Hydrology Program, the U.S. Geological Survey is studying contaminant-transport processes in an arid environment at the Amargosa Desert Research Site (http://nevada.usgs.gov/adrs/). The site is near waste-disposal facilities 20 kilometers east of Death Valley National Park. Low-level radioactive waste was buried in unlined trenches of varying depth during 1962-92. Hazardous chemical waste was buried in unlined trenches at an adjacent facility during 1970-88. Mean annual precipitation at the site from 1981 to 2000 was 108 millimeters. The unsaturated zone is aerobic down to the water table, which is about 110 m (meters) deep. Sampling infrastructure south and west of the facility includes a grid of vapor probes 1.5 m deep, a 23.8-m-deep background borehole (JFDB), and two approximately 100-m-deep boreholes (UZB-2 and UZB-3), which are 160 m and 100 m from the nearest trench, respectively, and are instrumented for multi-level sampling. Analytes detected in unsaturated-zone-vapor samples include elevated concentrations of tritium and carbon-14; three chlorofluorocarbon (CFC) compounds, eight chlorinated solvent compounds, and toluene, all at concentrations exceeding 1,000 parts per billion (ppb) in UZB-3, and at lower concentrations in UZB-2 and in the shallow-vapor-probe grid; and CO2 in concentrations up to 2% in UZB-3, whereas maximum CO2 concentrations in JFDB are less than 0.2%. With the notable exception of toluene, VOCs that are known to be highly biodegradable are generally absent or occur at low concentrations (1,000 ppb) in UZB-3 are relatively recalcitrant to biodegradation in this environment. 4. The similarity among their vertical and radial concentration profiles indicates that the same vapor-transport phenomena are responsible for the observed elevated levels of CO2, hydrocarbons, and radionuclides. The CO2- and VOC-concentration data will be used to enhance ongoing efforts to develop process-based models of contaminant

  14. COPD patient satisfaction with ipratropium bromide/albuterol delivered via Respimat: a randomized, controlled study

    Directory of Open Access Journals (Sweden)

    Ferguson GT

    2013-03-01

    Full Text Available Gary T Ferguson,1 Mo Ghafouri,2 Luyan Dai,2 Leonard J Dunn31Pulmonary Research Institute of Southeast Michigan, Livonia, MI, USA; 2Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA; 3Clinical Research of West Florida, Inc, Clearwater, FL, USABackground: Ipratropium bromide/albuterol Respimat inhaler (CVT-R was developed as an environmentally friendly alternative to ipratropium bromide/albuterol metered-dose inhaler (CVT-MDI, which uses a chlorofluorocarbon propellant.Objective: The objective of this study was to evaluate patient satisfaction, device usage, and long-term safety of CVT-R compared to CVT-MDI, and to the simultaneous administration of ipratropium bromide hydrofluoroalkane (HFA; I and albuterol HFA (A metered-dose inhalers as dual monotherapies (I + A.Design: This is a 48-week, open-label, randomized, active-controlled, parallel-group study (n = 470 comparing CVT-R to CVT-MDI and to I + A.Participants: Patients were at least 40 years of age, diagnosed with chronic obstructive pulmonary disease (COPD, and current or exsmokers.Interventions: Patients were randomized to receive: (1 CVT-R, one inhalation four times daily (QID; or (2 CVT-MDI, two inhalations QID; or (3 I + A two inhalations of each inhaler QID.Main measures: Patient Satisfaction and Preference Questionnaire (PASAPQ performance score (primary endpoint and adverse events.Key results: PASAPQ performance score was significantly higher (CVT-R versus CVT-MDI, 9.6; and CVT-R versus I + A, 6.2; both P < 0.001 when using CVT-R compared to CVT-MDI or I + A at all visits starting from week 3, while CVT-MDI and I + A treatment groups were similar. Time to first COPD exacerbation was slightly longer in the CVT-R group compared to the other treatment groups, although it did not reach statistical significance (CVT-R versus CVT-MDI, P = 0.57; CVT-R versus I + A, P = 0.22. Rates of withdrawal and patient refusal to continue treatment were lower in CVT-R compared with CVT

  15. Accuracy of CFC groundwater dating in a crystalline bedrock aquifer: Data from a site in southern Sweden

    Science.gov (United States)

    Bockgård, Niclas; Rodhe, Allan; Olsson, K. A.

    The concentrations of chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) and tritium were determined in groundwater in fractured crystalline bedrock at Finnsjön, Sweden. The specific goal was to investigate the accuracy of CFC dating in such an environment, taking potential degradation and mixing of water into consideration. The water was sampled to a depth of 42 m in three boreholes along an 800-m transect, from a recharge area to a local discharge area. The CFC-113 concentration was at the detection limit in most samples. The apparent recharge date obtained from CFC-11 was earlier than from CFC-12 for all samples, with a difference of over 20 years for some samples. The difference was probably caused by degradation of CFC-11. The CFC-12 dating of the samples ranged from before 1945 to 1975, with the exception of a sample from the water table, which had a present-day concentration. Conclusions about flow paths or groundwater velocity could not be drawn from the CFCs. The comparison between CFC-12 and tritium concentrations showed that most samples could be unmixed or mixtures of waters with different ages, and the binary mixtures that matched the measured concentrations were determined. The mixing model approach can be extended with additional tracers. Précision de la datation au CFC dans un aquifère rocheux-fracturé: données d'un site du sud de la Suède. Les concentrations en chlorofluorocarbones (CFC-11, CFC-12, CFC-113) et entritium ont été déterminées dans l'eau souterraine d'un massif fracturé à Finnsjön en Suède. Le but de cette étude est de mieux cerner la précision de la méthode de datation au CFC dans ce type d'environnement hydrogéologique, tout en considérant d'éventuels phénomènes de dégradation et de mélange d'eaux. L'eau a été échantillonnée à une profondeur de 42 mètres dans trois forages alignés sur 800 mètres entre une zone de recharge et une zone de déversement. Les concentrations en CFC-113 sont dans la plupart

  16. Altitude, age, and quality of groundwater, Papio-Missouri River Natural Resources District, eastern Nebraska, 1992 to 2009

    Science.gov (United States)

    McGuire, Virginia L.; Ryter, Derek W.; Flynn, Amanda S.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Papio-Missouri River Natural Resources District (PMRNRD), conducted this study to map the water-level altitude of 2009 within the Elkhorn River Valley, Missouri River Valley, and Platte River Valley alluvial aquifers; to present the predevelopment potentiometric-surface altitude within the Dakota aquifer; and to describe the age and quality of groundwater in the five principal aquifers of the PMRNRD in eastern Nebraska using data collected from 1992 to 2009. In addition, implications of alternatives to the current PMRNRD groundwater-quality monitoring approach are discussed. In the PMRNRD, groundwater altitude, relative to National Geodetic Vertical Datum of 1929, ranged from about 1,080 feet (ft) to 1,180 ft in the Elkhorn River Valley alluvial aquifer and from about 960 ft to 1,080 ft in the Missouri River Valley and Platte River Valley alluvial aquifers. In the PMRNRD, the estimated altitude of the potentiometric surface of the Dakota aquifer, predevelopment, ranged from about 1,100 ft to 1,200 ft. To assess groundwater age and quality, groundwater samples were collected from a total of 217 wells from 1992 to 2009 for analysis of various analytes. Groundwater samples collected in the PMRNRD from 1992 to 2009 and interpreted in this report were analyzed for age-dating analytes (chlorofluorocarbons), dissolved gases, major ions, trace elements, nutrients, stable isotope ratios, pesticides and pesticide degradates, volatile organic compounds, explosives, and 222radon. Apparent groundwater age was estimated from concentrations of chlorofluorocarbons measured in samples collected in 2000. Apparent groundwater-recharge dates ranged from older than 1940 in samples from wells screened in the Missouri River Valley alluvial aquifer to the early 1980s in samples from wells screened in the Dakota aquifer. Concentrations of major ions in the most recent sample per well collected from 1992 to 2009 indicate that the

  17. Hydrogen emissions and their effects on the arctic ozone losses. Risk analysis of a global hydrogen economy; Wasserstoff-Emissionen und ihre Auswirkungen auf den arktischen Ozonverlust. Risikoanalyse einer globalen Wasserstoffwirtschaft

    Energy Technology Data Exchange (ETDEWEB)

    Feck, Thomas

    2009-07-01

    Hydrogen (H{sub 2}) could be used as one of the major components in our future energy supply in an effort to avoid greenhouse gas emissions. ''Green'' hydrogen in particular, which is produced from renewable energy sources, should significantly reduce emissions that damage the climate. Despite this basically environmentally-friendly property, however, the complex chain of interactions of hydrogen with other compounds means that the implications for the atmosphere must be analysed in detail. For example, H{sub 2} emissions, which could increase the tropospheric H{sub 2} inventory, can be released throughout the complete hydrogen process chain. H{sub 2} enters the stratosphere via the tropical tropopause and is oxidised there to form water vapour (H{sub 2}O). This extra water vapour causes increased radiation in the infrared region of the electromagnetic spectrum and thus causes the stratosphere to cool down. Both the increase in H{sub 2}O and the resulting cooling down of the stratosphere encourage the formation of polar stratospheric clouds (PSC) and liquid sulphate aerosols, which facilitate the production of reactive chlorine, which in turn currently leads to dramatic ozone depletion in the polar stratosphere. In the future, H{sub 2} emissions from a global hydrogen economy could therefore encourage stratospheric ozone depletion in the polar regions and thus inhibit the ozone layer in recovering from the damage caused by chlorofluorocarbons (CFCs). In addition to estimating possible influences on the trace gas composition of the stratosphere, one of the main aims of this thesis is to evaluate the risk associated with increased polar ozone depletion caused by additional H{sub 2} emissions. Studies reported on here have shown that even if around 90% of today's fossil primary energy input was to be replaced by hydrogen and if around 9.5% of the gas was to escape in a ''worst-case'' scenario, the additional ozone loss for

  18. Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs

    Science.gov (United States)

    Focazio, Michael J.; Plummer, L. Neil; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.

    1998-01-01

    Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water

  19. Groundwater flow, quality (2007-10), and mixing in the Wind Cave National Park area, South Dakota

    Science.gov (United States)

    Long, Andrew J.; Ohms, Marc J.; McKaskey, Jonathan D.R.G.

    2012-01-01

    major hydrologic processes. Finally, conservative tracers were weighted preferentially in model calibration, which distributed model errors of optimized values, or residuals, more appropriately than would otherwise be the case The latter item also provides an estimate of the relative effect of geochemical evolution along flow paths in comparison to mixing. The end-member mixing model estimated that Wind Cave sites received 38 percent of their groundwater inflow from local surface recharge, 34 percent from the upgradient Precambrian aquifer, 26 percent from surface recharge to the west, and 2 percent from regional flow. Artesian springs primarily received water from end members assumed to represent regional groundwater flow. Groundwater samples were collected and analyzed for chlorofluorocarbons, dissolved gasses (argon, carbon dioxide, methane, nitrogen, and oxygen), and tritium at selected sites and used to estimate groundwater age. Apparent ages, or model ages, for the Madison aquifer in the study area indicate that groundwater closest to surface recharge areas is youngest, with increasing age in a downgradient direction toward deeper parts of the aquifer. Arsenic concentrations in samples collected for this study ranged from 0.28 to 37.1 micrograms per liter (μg/L) with a median value of 6.4 μg/L, and 32 percent of these exceeded 10 μg/L. The highest arsenic concentrations in and near the study area are approximately coincident with the outcrop of the Minnelusa Formation and likely originated from arsenic in shale layers in this formation. Sample concentrations of nitrate plus nitrite were less than 2 milligrams per liter for 92 percent of samples collected, which is not a concern for drinking-water quality. Water samples were collected in the park and analyzed for five trace metals (chromium, copper, lithium, vanadium, and zinc), the concentrations of which did not correlate with arsenic. Dye tracing indicated hydraulic connection between three water bodies in

  20. The Arctic Grand Challenge: Abrupt Climate Change

    Science.gov (United States)

    Wilkniss, P. E.

    2003-12-01

    products as greenhouse gases to their regions of origin. Thus multinational company operations are affected by their own activities. There is a strong, convincing case, that these industrial giants must be involved in Arctic partnerships of the grand challenge. A most instructive, very successful example is the collaboration by the chemical companies after the discovery of the polar ozone holes, followed by the replacement of the culprit chlorofluorocarbon compounds. Public relations and involvement/education: The IPY offers a unique opportunity to showcase and drive home, into homes, the seriousness of the issue, Hollywood/Madison Avenue/ NASA style, nothing else will do. Ultimately we need to be mindful that "civilizations are ephemeral compared to species. -What we need is a primer on science, clearly written and unambiguous in its meaning-a primer for anyone interested in the state of the Earth and how to survive and live well on it." (James Lovelock, Science, 08/05/98). - Let's start in the Arctic-NOW.

  1. Fiber-Optic Determination of N2, O2, and Fuel Vapor in the Ullage of Liquid-Fuel Tanks

    Science.gov (United States)

    Nguyen, Quang-Viet

    2008-01-01

    A fiber-optic sensor system has been developed that can remotely measure the concentration of molecular oxygen (O2), nitrogen (N2), hydrocarbon vapor, and other gases (CO2, CO, H2O, chlorofluorocarbons, etc.) in the ullage of a liquid-fuel tank. The system provides an accurate and quantitative identification of the above gases with an accuracy of better than 1 percent by volume (for O2 or N2) in real-time (5 seconds). In an effort to prevent aircraft fuel tank fires or explosions similar to the tragic TWA Flight 800 explosion in 1996, OBIGGS are currently being developed for large commercial aircraft to prevent dangerous conditions from forming inside fuel tanks by providing an inerting gas blanket that is low in oxygen, thus preventing the ignition of the fuel/air mixture in the ullage. OBIGGS have been used in military aircraft for many years and are now standard equipment on some newer large commercial aircraft (such as the Boeing 787). Currently, OBIGGS are being developed for retrofitting to existing commercial aircraft fleets in response to pending mandates from the FAA. Most OBIGGS use an air separation module (ASM) that separates O2 from N2 to make nitrogen-enriched air from compressed air flow diverted from the engine (bleed air). Current OBIGGS systems do not have a closed-loop feedback control, in part, due to the lack of suitable process sensors that can reliably measure N2 or O2 and at the same time, do not constitute an inherent source of ignition. Thus, current OBIGGS operate with a high factor-of-safety dictated by process protocol to ensure adequate fuel-tank inerting. This approach is inherently inefficient as it consumes more engine bleed air than is necessary compared to a closed-loop controlled approach. The reduction of bleed air usage is important as it reduces fuel consumption, which translates to both increased flight range and lower operational costs. Numerous approaches to developing OBIGGS feedback-control sensors have been under

  2. Preliminary assessment of water chemistry related to groundwater flooding in Wawarsing, New York, 2009-11

    Science.gov (United States)

    Brown, Craig J.; Eckhardt, David A.; Stumm, Frederick; Chu, Anthony

    2012-01-01

    Water-quality samples collected in an area prone to groundwater flooding in Wawarsing, New York, were analyzed and assessed to better understand the hydrologic system and to aid in the assessment of contributing water sources. Above average rainfall over the past decade, and the presence of a pressurized water tunnel that passes about 700 feet beneath Wawarsing, could both contribute to groundwater flooding. Water samples were collected from surface-water bodies, springs, and wells and analyzed for major and trace inorganic constituents, dissolved gases, age tracers, and stable isotopes. Distinct differences in chemistry exist between tunnel water and groundwater in unconsolidated deposits and in bedrock, and among groundwater samples collected from some bedrock wells during high head pressure and low head pressure of the Rondout-West Branch Tunnel. Samples from bedrock wells generally had relatively higher concentrations of sulfate (SO42-), strontium (Sr), barium (Ba), and lower concentrations of calcium (Ca) and bicarbonate (HCO3-), as compared to unconsolidated wells. Differences in stable-isotope ratios among oxygen-18 to oxygen-16 (δ18O), hydrogen-2 to hydrogen-1 (δ2H), sulfur-34 to sulfur-32(δ34S) of SO42-, Sr-87 to Sr-86 (87Sr/86Sr), and C-13 to C-12 (δ13C) of dissolved inorganic carbon (DIC) indicate a potential for distinguishing water in the Delaware-West Branch Tunnel from native groundwater. For example, 87Sr/86Sr ratios were more depleted in groundwater samples from most bedrock wells, as compared to samples from surface-water sources, springs, and wells screened in unconsolidated deposits in the study area. Age-tracer data provided useful information on pathways of the groundwater-flow system, but were limited by inherent problems with dissolved gases in bedrock wells. The sulfur hexafluoride (SF6) and (or) chlorofluorocarbons (CFCs) apparent recharge years of most water samples from wells screened in unconsolidated deposits and springs ranged

  3. 北方干旱区地下水补给源问题讨论%A discussion of groundwater recharge sources in arid areas of North China

    Institute of Scientific and Technical Information of China (English)

    陈建生; 王庆庆

    2012-01-01

    chlorofluorocarbons (CFC) method. Therefore, it is deduced that the percolating water in the Qiangtang Basin recharges the groundwater of the Inner Mongolia Plateau, the North China Plain, and the wetlands in North China, in a manner of deep circulation. The groundwater deep-circulation channels may be distributed along the West China Craton, the East China Craton, and the suture zone of microplates. It can be concluded that the deep confined water distributed along the suture zone of microplates is correlated with the deep-circulating water, and the high-conductivity and low-velocity layers in the middle crust along the suture zone are caused by the groundwater deep-circulation channels.

  4. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2 from in situ and air archive observations

    Directory of Open Access Journals (Sweden)

    P. G. Simmonds

    2016-01-01

    Full Text Available High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2. These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs and hydrochlorofluorocarbons (HCFCs. The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an annual average rate of growth in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The annual average Northern Hemisphere (NH mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called “bottom up” emissions reported by the United Nations Framework Convention on Climate Change (UNFCCC

  5. Global emission estimates and radiative impact of C4F10, C5F12, C6F14, C7F16 and C8F18

    Science.gov (United States)

    Ivy, D. J.; Rigby, M.; Baasandorj, M.; Burkholder, J. B.; Prinn, R. G.

    2012-08-01

    estimated in this study. In addition, we present measured infrared absorption spectra for C7F16 and C8F18, and estimate their radiative efficiencies and global warming potentials (GWPs). We find that C8F18's radiative efficiency is similar to trifluoromethyl sulfur pentafluoride's (SF5F3) at 0.57 W m-2 ppb-1, which is the highest radiative efficiency of any measured atmospheric species. Using the 100-yr time horizon GWPs, the total radiative impact of the high molecular weight perfluorocarbons emissions are also estimated; we find the high molecular weight PFCs peak contribution was in 1997 at 24 000 Gg of carbon dioxide (CO2) equivalents and has decreased by a factor of three to 7300 Gg of CO2 equivalents in 2010. This 2010 cumulative emission rate for the high molecular weight PFCs is comparable to: 0.02% of the total CO2 emissions, 0.81% of the total hydrofluorocarbon emissions, or 1.07% of the total chlorofluorocarbon emissions projected for 2010 (Velders et al., 2009). In terms of the total PFC emission budget, including the lower molecular weight PFCs, the high molecular weight PFCs peak contribution was also in 1997 at 15.4% and was 6% of the total PFC emissions in CO2 equivalents in 2009.

  6. Preparing for climate change.

    Science.gov (United States)

    Holdgate, M

    1989-01-01

    chlorofluorocarbons (CFCs) have been released in great quantities through their use in aerosol sprays, refrigerator fluids, and insulating foams. We can get rid of CFCs and curb the pollutants generating ozone, but it will be difficult to put the brake on either methane or nitrous oxide. And the reduction in carbon dioxide emissions will demand major changes in energy policy as well as action to slow deforestation. It appears that we are already committed to rising temperatures and sea levels. The question is by how much, in which areas? A number of things can be done to prepare for these changes: Governments must recognize that there is a problem; Better models must be worked out, especially to define where the greatest impacts from climate change and sea level rise will hit; Reference scenarios must be developed to see what the impacts are likely to be in ecological, agricultural, social and economic terms; Every country should develop "avoidance strategies" to minimize risk (for example, by not building on land likely to be flooded); We must cut down on the amount of greenhouse gases released into the atmosphere from human activities, by eliminating CFCs and adopting energy conservation programs and other measures to minimize CO2 release; Global agreements to protect the atmosphere are needed. PMID:12285901

  7. A selected ion flow tube investigation of the positive ion chemistry of a number of bromine containing fully and partially halogenated hydrocarbons

    International Nuclear Information System (INIS)

    The reaction of ions with neutral molecules play a significant, and often dominant, role in the chemistry of many gaseous plasma environments, including the interstellar medium, planetary ionospheres and industrial plasmas. This had led to many publications reporting ion-molecule reaction rate coefficients and reaction pathways (product ion distributions). Such critical data are invaluable in the understanding of the formation and abundance of ions and neutral molecules present in neutral and man-made plasma, and to predict how such plasmas chemically and physically evolve. There have been many studies investigating the positive ion chemistry of chlorofluorocarbons (CFCs), and a number of studies have explored the positive ion chemistry of their replacements, the perfluorocarbones (PFCs). In part these studies have been undertaken because of their relevance to plasmas, and of more specific interest in terms of their relevance to industrial plasma processing. Halogenated molecules are commonly used in plasma processes. In contrast to fluorinated and/or chlorinated species, little attention has been directed to the reactions of positive ions with bromine containing molecules. Yet a systematic study of these reactions permits useful comparison with the ion chemistry of fully and partially fluorinated/chlorinated compounds. This in turn improves our fundamental understanding of ion-molecule reactions, and ultimately leads, for example, to better models to predict the optimum conditions needed to operate industrial plasma processes. In this paper the thermal biomolecular rate coefficients and product ion branching ratios for the reactions of the positive ions (in order of increasing recombination energy) H2O+, N2O+, O+, CO2+, CO+, N+, and N2+ with the bromine containing molecules CF3Br, CF2Br2, CFBr3, CF2BrCl, CFBr2Cl, CBrCl3, CH3Br, CH2Br2, CH2FBr, CHF2Br, CHFBr2, CH2BrCl, CHBrCl2, CHBr2Cl, CF3CF2Br, and CF2BrCF2Br at 300 K are reported. This represents the most

  8. Atmospheric Science and the CFC Industry

    Science.gov (United States)

    Steed, J. M.

    2012-12-01

    Industry involvement with developing atmospheric science and subsequent regulations to protect ozone was unusual. Chlorofluorocarbon manufacturers were research-based businesses accustomed to understanding the science behind product-related issues. When Lovelock's measurements in 1971 implied most of the cumulative production of CFCs remained in the atmosphere, global CFC producers funded academic research to identify natural sinks for the materials. The Fluorocarbon Program Panel (FPP) began in 1972, but changed focus to atmospheric photochemistry following Rowland and Molina's work in 1974. Despite early vociferous opposition, especially by the CFC-using aerosol industry, to any regulations, leaders among the producers worked to build their scientific understanding, expanding FPP funding and launching internal work in modeling and ozone trend analysis. The key first question for industry was not how much depletion might occur, but whether it would occur at all. If so, regardless of the amount, regulations and a major transition would be required in CFC-using industries, and the response would need to be global and prompt. So long as that basic question was in doubt, some businesses and countries would resist the economic cost of action. In the meantime, the producing industry worked to identify potential alternatives and to communicate atmospheric science to the downstream industries. Although the industry science effort was often disparaged as an attack on "real" science, my only assignment when I joined DuPont's Central Research Department in 1979 was to understand and contribute to the science, keeping both the company and our customers informed. Our modeling results were published freely. FPP funding led to better knowledge of the ClO + O rate constant, significantly increasing depletion in model calculations; supported the development of the techniques used to measure in situ atmospheric ClO, so important in later strengthening the case for chlorine

  9. The effect of heat and mass transfer on the cellular plastic insulation and the long-term aging

    Energy Technology Data Exchange (ETDEWEB)

    Fan Youchen [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1997-12-31

    To produce environmental-friendly products, foamed plastic industries are facing the challenge to replace the traditional blowing agents chlorofluorocarbons (CFCs) with zero ozone depletion potential (ODP) alternatives. After a series of studies were completed, more understandings and new findings have been achieved with respect to the rigid closed-cell cellular plastic insulations or foamed plastic insulations (FPIs). The mechanism of heat transfer within the FPIs was examined. A new formula for calculating the solid polymer matrix thermal conductivity has been deduced based on the law of energy conservation and Fourier equation of heat conduction. All the parameters involved in this formula can be easily measured. By comparing the simulation results with measurements, the Brokaw equation is recommended for the prediction of the thermal conductivity of a cell-gas mixture. The foamed plastic deformation was also discussed. A new model has been established for predicting the elastic modulus of the foamed plastics. In comparison to the published measurements, it was found that the new model gives fairly good results. A diffusion chamber has been designed and constructed for measuring the gaseous transport properties within the FPIs. To overcome the difficulties of the traditional method, a new measurement procedure and post test data treatment have been suggested. The measurement accuracy is equivalent to the traditional method with an exception of much short time being required. The diffusion coefficients of CO{sub 2}, O{sub 2}, and N{sub 2} within five n-pentane/CO{sub 2} based polyurethane (PUR) foams have been obtained from the diffusion chamber tests. Measurements showed that the relationship between the gaseous diffusion coefficients within FPIs and temperature follows the Arrhenius type. No identical relationship between diffusion coefficients and foam density was reached. To predict the long-term aging property of CFC-free foamed plastic insulations, a two

  10. The analytical methods used in examining resistance of hydrogeological systems to anthropogenic pollution

    Science.gov (United States)

    Najman, Joanna; Bielewski, Jarosław; Śliwka, Ireneusz

    2013-04-01

    key words: gas chromatography (GC) measurement method, groundwater dating, He, SF6, F-11, F-12, Ar, Ne. In this work the method for evaluating resistance hydrogeological systems to anthropogenic pollution using environmental tracers is described. Resistance groundwater systems to anthropogenic pollution is correlated with the age of water, which can be determined by means of environmental tracers SF6, F-11, F-12 [1] and He. To correct measured values of He and SF6 the temperature of recharge and the excess air is needed and can be determined by measuring Ne and Ar concentrations in groundwater. This paper describes three measurement GC systems to determine the concentrations of greenhouse gases: sulfur hexafluoride (SF6) and chlorofluorocarbons F-11, F-12 [2], the noble gases neon (Ne), argon (Ar) [3] and helium (He) [4] in groundwater. The first system for measurements of the concentration of SF6, F-11 and F-12 consists of a gas chromatograph, type N504 is supplied with nitrogen carrier gas with a purity of 6.0. It is equipped with two packed columns K1 and K2 running at 60°C with the use of the "back-flush" column switching and electron capture detector (ECD) operating at 300°C. Second system for measuring the concentration of the noble gases argon and neon, is composed of a dual Shimadzu gas chromatograph. It is equipped with two columns K4 and K5 operating at 30°C, thermalconductivity detector (TCD) for analysis of argon and helium detector with pulse discharge (PDHID) for analysis of neon. This chromatograph is powered by helium carrier gas 6.0. The third system measures the concentration of helium, consists of a gas chromatograph equipped with a TCD detector and three packed columns filled with molecular sieve type 5A and activated carbon. The carrier gas in this system is argon 6.0. Detection limit, LOD for each measurement systems for the tested compounds are: 0,06 fmol/L for SF6, 15 fmol/L for F-11, 10 fmol/L for F-12, 1,9•10-8 cm3STP/cm3 for Ne, 3,1

  11. Heat exchange characteristics of zeotropic mixtures in heat exchangers in high temperature heat pump%高温热泵工况下非共沸工质在换热器中的换热特性

    Institute of Scientific and Technical Information of China (English)

    刘兆永; 赵力; 赵学政

    2011-01-01

    为了探究非共沸工质与换热流体之间的相变传热温差特性,在单级蒸气压缩式水-水高温热泵系统实验台上,以R290/R600(称为Z1,质量比17%/83%)为工质进行了多工况的实验研究.实验发现,工质Z1在冷凝器中会出现最大传热温差,且最大传热温差的位置会随着冷凝器中水流量的减小而向冷凝器的冷端移动;在蒸发器中会出现最小传热温差,其位置随着蒸发器中水流量的减小而向蒸发器的冷端移动.分析结果表明,在蒸发器侧工况恒定时,冷凝器侧最大传热温差的出现会使系统的循环效率降低,冷凝器中因不可逆传热引起的可用能损失增大;在冷凝器侧工况不变时,蒸发器侧最小传热温差的出现会使系统的循环效率上升,蒸发器中因不可逆传热引起的可用能损失减小.%Zeotropic mixtures are popular alternatives to chlorofluorocarbons ( CFCs ) and hydrochlorofluorocarbons (HCFCs) in the high temperature heat pump system. Zeotropic mixtures exhibit two major characteristics during phase change: temperature gliding and nonlinear relationship between temperature and enthalpy. In order to reveal the distribution of temperature difference between zeotropic mixture and heat transfer fluid in heat exchangers and get clear how temperature differences affect the performance of the system, experiments were carried out with the binary mixture Z1 in the high temperature water-water heat pump system, which was composed of 17% R290 and 83% R600 (mass ratio). The experimental results showed that as the water flow rate decreased the maximum temperature difference occurred in the condenser and its location moved to the cold end of the condenser, while the minimum temperature difference occurred in the evaporator and its location moved to the cold end of the evaporator. It was found that the occurrence of maximum temperature difference decreased the coefficient of performance of the system and increased the

  12. Land-use controls on sources and fate of nitrate in shallow groundwater of an agricultural area revealed by multiple environmental tracers

    Science.gov (United States)

    Koh, Dong-Chan; Mayer, Bernhard; Lee, Kwang-Sik; Ko, Kyung-Seok,

    2010-10-01

    Sources and transformation processes of nitrate in groundwater from shallow aquifers were investigated in an agricultural area in the mid-western part of South Korea using a multi-tracer approach including δ 2H and δ 18O values of water, δ 15N and δ 18O values of nitrate, Cl/Br ratios and chlorofluorocarbons (CFCs). The study area was comprised of four land-use types with natural areas at higher altitudes, upland areas with fruit orchards, paddy fields and residential areas at lower elevations. The isotopic composition of water was suitable for distinguishing groundwater that had infiltrated in the higher elevation natural areas with lower δ 2H and δ 18O values from groundwater underneath paddy fields that was characterized by elevated δ 2H and δ 18O values due to evaporation. δ 18O-H 2O values and Cl - concentrations indicated that groundwater and contaminant sources were derived from three land-use types: natural areas, residential areas and paddy fields. Groundwater age determination based on CFCs showed that nitrate contamination of groundwater is primarily controlled by historic nitrogen loadings at least in areas with higher nitrate contamination. Nitrate sources were identified using the stable isotope composition of nitrate and Cl/Br ratios. Higher δ 15N-NO 3- values and Cl/Br ratios of 300 to 800 in residential areas indicated that waste water and septic effluents were major nitrate sources whereas lower δ 15N-NO 3- values and Cl/Br ratios of 100 to 700 in upland areas suggested that synthetic fertilizers constituted a major source of nitrate contamination of aquifers. With only few exceptions in the natural area, contributions of atmospheric nitrate were insignificant due to the resetting of δ 18O-NO 3- values via immobilization and re-mineralization of nitrate in the soil zone. In groundwater underneath paddy fields, 30% of samples had δ 18O-NO 3- values at least 2‰ higher than expected for nitrate formed by chemolithoautotrophic

  13. Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies

    Science.gov (United States)

    Hoffmann, Lars; Hoppe, Charlotte; Müller, Rolf; Dutton, Geoffrey S.; Gille, John C.; Griessbach, Sabine; Jones, Ashley; Meyer, Catrin I.; Spang, Reinhold; Volk, C. Michael; Walker, Kaley A.

    2015-04-01

    Chlorofluorocarbons (CFCs) play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their stratospheric loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer-tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11) and CF2Cl2 (CFC-12). We present new estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 yr for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), the HIgh Resolution Dynamics Limb Sounder (HIRDLS), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We found a CFC-11/CFC-12 lifetime ratio of 0.47 ± 0.08 and a CFC-12 lifetime of 112(96 - 133) yr for ACE-FTS, a ratio of 0.46 ± 0.07 and a lifetime of 113(97 - 134) yr for HIRDLS, and a ratio of 0.46 ± 0.08 and a lifetime of 114(98 - 136) yr for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.46 ± 0.04 and the CFC-12 lifetime estimate is 113(103 - 124) yr. These results are in excellent agreement with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC) reassessment, which recommends lifetimes of 52(43 - 67) yr for CFC-11 and 102(88 - 122) yr for CFC-12, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled EMAC/CLaMS model we found a CFC-11/CFC-12 lifetime ratio

  14. Observed and simulated time evolution of HCl, ClONO2, and HF total column abundances

    Science.gov (United States)

    Kohlhepp, R.; Ruhnke, R.; Chipperfield, M. P.; De Mazière, M.; Notholt, J.; Barthlott, S.; Batchelor, R. L.; Blatherwick, R. D.; Blumenstock, Th.; Coffey, M. T.; Demoulin, P.; Fast, H.; Feng, W.; Goldman, A.; Griffith, D. W. T.; Hamann, K.; Hannigan, J. W.; Hase, F.; Jones, N. B.; Kagawa, A.; Kaiser, I.; Kasai, Y.; Kirner, O.; Kouker, W.; Lindenmaier, R.; Mahieu, E.; Mittermeier, R. L.; Monge-Sanz, B.; Morino, I.; Murata, I.; Nakajima, H.; Palm, M.; Paton-Walsh, C.; Raffalski, U.; Reddmann, Th.; Rettinger, M.; Rinsland, C. P.; Rozanov, E.; Schneider, M.; Senten, C.; Servais, C.; Sinnhuber, B.-M.; Smale, D.; Strong, K.; Sussmann, R.; Taylor, J. R.; Vanhaelewyn, G.; Warneke, T.; Whaley, C.; Wiehle, M.; Wood, S. W.

    2012-04-01

    Time series of total column abundances of hydrogen chloride (HCl), chlorine nitrate (ClONO2), and hydrogen fluoride (HF) were determined from ground-based Fourier transform infrared (FTIR) spectra recorded at 17 sites belonging to the Network for the Detection of Atmospheric Composition Change (NDACC) and located between 80.05° N and 77.82° S. By providing such a near-global overview on ground-based measurements of the two major stratospheric chlorine reservoir species, HCl and ClONO2, the present study is able to confirm the decrease of the atmospheric inorganic chlorine abundance during the last few years. This decrease is expected following the 1987 Montreal Protocol and its amendments and adjustments, where restrictions and a subsequent phase-out of the prominent anthropogenic chlorine source gases (solvents, chlorofluorocarbons) were agreed upon to enable a stabilisation and recovery of the stratospheric ozone layer. The atmospheric fluorine content is expected to be influenced by the Montreal Protocol, too, because most of the banned anthropogenic gases also represent important fluorine sources. But many of the substitutes to the banned gases also contain fluorine so that the HF total column abundance is expected to have continued to increase during the last few years. The measurements are compared with calculations from five different models: the two-dimensional Bremen model, the two chemistry-transport models KASIMA and SLIMCAT, and the two chemistry-climate models EMAC and SOCOL. Thereby, the ability of the models to reproduce the absolute total column amounts, the seasonal cycles, and the temporal evolution found in the FTIR measurements is investigated and inter-compared. This is especially interesting because the models have different architectures. The overall agreement between the measurements and models for the total column abundances and the seasonal cycles is good. Linear trends of HCl, ClONO2, and HF are calculated from both measurement and

  15. EFFECTS OF TRITIUM EXPOSURE ON UHMW-PE, PTFE, AND VESPEL

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E; Kirk Shanahan, K

    2006-05-31

    general concept of minimizing chlorofluorocarbon polymers in tritium systems.

  16. Hydrogeologic setting and simulation of groundwater flow near the Canterbury and Leadville Mine Drainage Tunnels, Leadville, Colorado

    Science.gov (United States)

    Wellman, Tristan P.; Paschke, Suzanne S.; Minsley, Burke; Dupree, Jean A.

    2011-01-01

    -current resistivity field survey was performed to evaluate the geologic structure of the study area. The results show that the Canterbury Tunnel is located in a downthrown structural block that is not in direct physical connection with the Leadville Mine Drainage Tunnel. The presence of this structural discontinuity implies there is no direct groundwater pathway between the tunnels along a laterally continuous bedrock unit. Water-quality results for pH and major-ion concentrations near the Canterbury Tunnel showed that acid mine drainage has not affected groundwater quality. Stable-isotope ratios of hydrogen and oxygen in water indicate that snowmelt is the primary source of groundwater recharge. On the basis of chlorofluorocarbon and tritium concentrations and mixing ratios for groundwater samples, young groundwater (groundwater recharged after 1953) was indicated at well locations upgradient from and in a fault block separate from the Canterbury Tunnel. Samples from sites downgradient from the Canterbury Tunnel were mixtures of young and old (pre-1953) groundwater and likely represent snowmelt recharge mixed with older regional groundwater that discharges from the bedrock units to the Arkansas River valley. Discharge from the Canterbury Tunnel contained the greatest percentage of old (pre-1953) groundwater with a mixture of about 25 percent young water and about 75 percent old water. A calibrated three-dimensional groundwater model representing high-flow conditions was used to evaluate large-scale flow characteristics of the groundwater and to assess whether a substantial hydraulic connection was present between the Canterbury Tunnel and Leadville Mine Drainage Tunnel. As simulated, the faults restrict local flow in many areas, but the fracture-damage zones adjacent to the faults allow groundwater to move along faults. Water-budget results indicate that groundwater flow across the lateral edges of the model controlled the majority of flow in and out of the aquifer (79 percent and

  17. Questa baseline and pre-mining ground-water quality investigation. 14. Interpretation of ground-water geochemistry in catchments other than the Straight Creek catchment, Red River Valley, Taos County, New Mexico, 2002-2003

    Science.gov (United States)

    Nordstrom, D. Kirk; McCleskey, R. Blaine; Hunt, Andrew G.; Naus, Cheryl A.

    2005-01-01

    determined on selected samples. Dissolved organic carbon (DOC), mercury, sulfate stable isotope composition (d34S and d18O of sulfate), stable isotope composition of water (d2H and d18O of water) were measured for selected samples. Chlorofluorocarbons (CFC) and 3He and 3H were measured for age dating on selected samples. Linear regressions from the Straight Creek ground-water data were used to compare ground-water chemistry trends in non-Straight Creek ground waters with Straight Creek alluvial ground-water chemistry dilution trends. Most of the solute trends for the ground waters are similar to those for Straight Creek but there are some notable exceptions. In lithologies that contain substantial pyrite mineralization, acid waters form with similar chemistries to those in Straight Creek and all the waters tend to be calcium-sulfate type. Hottentot ground waters contain substantially lower calcium concentrations relative to those in Straight Creek. This anomaly results from the exposure of rhyolite porphyry in the Hottentot scar and weathering zone. The rhyolite contains less calcium than the altered andesites and tuffs in the Straight Creek catchment and probably does not have the abundant gypsum and calcite. The Hansen ground waters have reached gypsum saturation and have similar calcium, magnesium, and beryllium concentrations as Straight Creek ground waters but have lower concentrations of fluoride, manganese, zinc, cobalt, nickel, copper, and lithium. Lower concentrations of elements related to mineralization at Hansen likely reflect the more distal location of Hansen with respect to intrusive centers that provided the heat source for hydrothermal alteration. The other ground water with water chemistry trends that are outside the Straight Creek trends was from an alluvial well from Capulin Canyon (CC2A). Although it had pH values near 6.0 and most major ions similar to the other Capulin Canyon ground waters, it contained high concentrations

  18. Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

    Science.gov (United States)

    Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

    2005-01-01

    selected samplings. One set of ground-water samples was collected for helium-3/tritium and chlorofluorocarbon (CFC) age dating. Several lines of evidence indicate that surface water is the primary input to the Straight Creek ground-water system. Straight Creek streamflow and water levels in wells closest to the apex of the Straight Creek debris fan and closest to Straight Creek itself appear to respond to the same seasonal inputs. Oxygen and hydrogen isotopic compositions in Straight Creek surface water and ground water are similar, and concentrations of most dissolved constituents in most Straight Creek surface-water and shallow (debris-flow and alluvial) aquifer ground-water samples correlate strongly with sulfate (concentrations decrease linearly with sulfate in a downgradient direction). After infiltration of surface water, dilution along the flow path is the dominant mechanism controlling ground-water chemistry. However, concentrations of some constituents can be higher in ground water than can be accounted for by concentrations in Straight Creek surface water, and additional sources of these constituents must therefore be inferred. Constituents for which concentrations in ground water can be high relative to surface water include calcium, magnesium, strontium, silica, sodium, and potassium in ground water from debris-flow and alluvial aquifers and manganese, calcium, magnesium, strontium, sodium, and potassium in ground water from the bedrock aquifer. All ground water is a calcium sulfate type, often at or near gypsum saturation because of abundant gypsum in the aquifer material developed from co-existing calcite and pyrite mineralization. Calcite dissolution, the major buffering mechanism for bedrock aquifer ground water, also contributes to relatively higher calcium concentrations in some ground water. The main source of the second most abundant cation, magnesium, is probably dissolution of magnesium-rich carbonates or silicates. Strontium may also be

  19. Ground-Water Quality and Potential Effects of Individual Sewage Disposal System Effluent on Ground-Water Quality in Park County, Colorado, 2001-2004

    Science.gov (United States)

    Miller, Lisa D.; Ortiz, Roderick F.

    2007-01-01

    In 2000, the U.S. Geological Survey, in cooperation with Park County, Colorado, began a study to evaluate ground-water quality in the various aquifers in Park County that supply water to domestic wells. The focus of this study was to identify and describe the principal natural and human factors that affect ground-water quality. In addition, the potential effects of individual sewage disposal system (ISDS) effluent on ground-water quality were evaluated. Ground-water samples were collected from domestic water-supply wells from July 2001 through October 2004 in the alluvial, crystalline-rock, sedimentary-rock, and volcanic-rock aquifers to assess general ground-water quality and effects of ISDS's on ground-water quality throughout Park County. Samples were analyzed for physical properties, major ions, nutrients, bacteria, and boron; and selected samples also were analyzed for dissolved organic carbon, human-related (wastewater) compounds, trace elements, radionuclides, and age-dating constituents (tritium and chlorofluorocarbons). Drinking-water quality is adequate for domestic use throughout Park County with a few exceptions. Only about 3 percent of wells had concentrations of fluoride, nitrate, and (or) uranium that exceeded U.S. Environmental Protection Agency national, primary drinking-water standards. These primary drinking-water standards were exceeded only in wells completed in the crystalline-rock aquifers in eastern Park County. Escherichia coli bacteria were detected in one well near Guffey, and total coliform bacteria were detected in about 11 percent of wells sampled throughout the county. The highest total coliform concentrations were measured southeast of the city of Jefferson and west of Tarryall Reservoir. Secondary drinking-water standards were exceeded more frequently. About 19 percent of wells had concentrations of one or more constituents (pH, chloride, fluoride, sulfate, and dissolved solids) that exceeded secondary drinking-water standards

  20. Estimation of transit times in a Karst Aquifer system using environmental tracers: Application on the Jeita Aquifer system-Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Hamdan, Ahmad

    2016-04-01

    Estimating transit times is essential for the assessment of aquifer vulnerability to contaminants. Groundwater in karst aquifer is assumed to be relatively young due to fast preferential pathways; slow flow components are present in water stored in the fissured matrix. Furthermore, transit times are site specific as they depend on recharge rates, temperatures, elevation, and flow media; saturated and unsaturated zones. These differences create significant variation in the groundwater age in karst systems as the water sampled will be a mix of different water that has been transported through different flow pathways (fissured matrix and conduits). Several methods can be applied to estimate water transit time of an aquifer such as artificial tracers, which provide an estimate for fast flow velocities. In this study, groundwater residence times in the Jeita spring aquifer (Lebanon) were estimated using several environmental tracers such as Chlorofluorocarbons (CFCs), Sulfur Hexafluoride (SF6), Helium-Tritium (3H, 3H- 3He). Additional stable isotope and major ion analysis was performed to characterize water types. Groundwater samples were collected from six different wells in the Jeita catchment area (Jurassic Kesrouane aquifer) as well as from the spring and cave itself. The results are reproducible for the Tritium-Helium method, unlike for the CFC/SF6 methods that yielded poor results due to sampling problems. Tritium concentrations in all groundwater samples show nearly the same concentration (~2.73 TU) except for one sample with relatively lower tritium concentration (~2.26 TU). Ages ranging from 0.07 ± 0.07 years to 23.59 ± 0.00 years were obtained. The youngest age is attributed to the spring/ cave while the oldest ages were obtained in wells tapping the fissured matrix. Neon in these samples showed considerable variations and high delta Ne in some samples indicating high excess air. Four (4) samples showed extreme excess air (Delta-Ne is greater than 70 %) and

  1. Dissemination of Climate Model Output to the Public and Commercial Sector

    Energy Technology Data Exchange (ETDEWEB)

    Robert Stockwell, PhD

    2010-09-23

    Climate is defined by the Glossary of Meteorology as the mean of atmospheric variables over a period of time ranging from as short as a few months to multiple years and longer. Although the term climate is often used to refer to long-term weather statistics, the broader definition of climate is the time evolution of a system consisting of the atmosphere, hydrosphere, lithosphere, and biosphere. Physical, chemical, and biological processes are involved in interactions among the components of the climate system. Vegetation, soil moisture, and glaciers are part of the climate system in addition to the usually considered temperature and precipitation (Pielke, 2008). Climate change refers to any systematic change in the long-term statistics of climate elements (such as temperature, pressure, or winds) sustained over several decades or longer. Climate change can be initiated by external forces, such as cyclical variations in the Earth's solar orbit that are thought to have caused glacial and interglacial periods within the last 2 million years (Milankovitch, 1941). However, a linear response to astronomical forcing does not explain many other observed glacial and interglacial cycles (Petit et al., 1999). It is now understood that climate is influenced by the interaction of solar radiation with atmospheric greenhouse gasses (e.g., carbon dioxide, chlorofluorocarbons, methane, nitrous oxide, etc.), aerosols (airborne particles), and Earth's surface. A significant aspect of climate are the interannual cycles, such as the El Nino La Nina cycle which profoundly affects the weather in North America but is outside the scope of weather forecasts. Some of the most significant advances in understanding climate change have evolved from the recognition of the influence of ocean circulations upon the atmosphere (IPCC, 2007). Human activity can affect the climate system through increasing concentrations of atmospheric greenhouse gases, air pollution, increasing

  2. Fundamentals of heterogeneously catalyzed reactions of environmental importance

    Science.gov (United States)

    Deshmukh, Subodh Shrinivas

    Reaction kinetics and spectroscopic characterization are valuable tools for understanding heterogeneously catalyzed chemical reactions. The objective of this work was to apply the tools of catalysis and reaction kinetics to understand the fundamentals of chemical surface phenomena for environmentally important reactions. This thesis presents our work in two areas of catalytic reactions for pollution abatement---"chlorofluorocarbon (CFC) treatment chemistry" and "sulfur-tolerant auto exhaust catalysts." The ozone depletion potential of CFCs has resulted in a great interest in the academic and industrial communities to find replacements for these chemicals. Hydrofluorocarbons (HFCs) are amongst the best "environmentally benign" candidates for CFC replacement. One selective pathway for the synthesis of HFCs is via the hydrodechlorination of CFCs. This route has the added benefit of destroying harmful CFC stockpiles and converting them into more useful chemicals. The work in Chapter 3 shows that parallel hydrogenation pathways starting from a common CF2 species can explain the formation of the products CH2F2 and CH4 for the hydrodechlorination of CF2Cl2 over Pd/AlF3. Transient kinetics experiments using C2H4 as a trapping agent for surface carbenes have provided evidence for the presence of CH2 species on the catalyst surface during this reaction. The absence of either coupling products or trapped products containing F suggests that the rate of hydrogenation of surface CF2 species is faster than that of surface CH2 species. Another important class of CFC reactions is oxide-catalyzed disproportionations to control the number and position of halogen atoms in the CFC/HFC molecule. Chapter 4 combines the use of reaction kinetics tools and spectroscopic characterization techniques to understand the adsorption and reaction of CF3CFCl 2 over gamma-Al2O3. The CF3CFCl 2 reaction over gamma-Al2O3 lead to a modification of the gamma-Al2O3 surface due to fluorination and the

  3. Projections of global emissions of fluorinated greenhouse gases in 2050

    Energy Technology Data Exchange (ETDEWEB)

    Gschrey, Barbara; Schwarz, Winfried [Oeko-Recherche Buero fuer Umweltforschung und -beratung GmbH, Frankfurt/Main (Germany)

    2009-11-15

    Emissions of fluorinated greenhouse gases are currently covered under the Montreal Protocol, which focuses on ozone-depleting substances such as CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons), and under the Kyoto Protocol, which controls emissions of HFCs (hydrofluorocarbons), PFCs (perfluorocarbons) and SF{sub 6} (sulfur hexafluoride). This study bridges the gap between political regimes and their reporting systems by giving an overview of banks and emissions of all fluorinated gases in 2005, and projections of banks and emissions of fluorinated gases in 2050. The Montreal Protocol and its amendments will eventually result in the full phase out of CFCs and HCFCs. Developed countries have already completed the phase out of CFCs and will reach full phase out of HCFCs by 2020. Developing countries, in contrast, will phase out CFCs by 2010 and HCFCs by 2030. Although climate-friendly technology is available for most applications, the risk occurs that substitutes for ozone-depleting substances rely on HFCs, which cause global warming. This study determines global emissions of HFCs, PFCs and SF{sub 6} (Kyoto F-gases) in 2050 in a ''business-as-usual'' scenario. The global population is expected to increase to ca. 8.7 billion people, and high economic growth of 3.5% per year is assumed. Emissions in 2050 are quantified for each sector of application as well as for developed and developing countries based on growth rates of each sector. In 2050, total global emissions of fluorinated greenhouse gases are projected to amount to 4 GT CO{sub 2} eq. which equals ca. 5.9% of the total greenhouse gas emissions at this time. Compared to a relatively small share of F-gas emissions ranging around 1.3% of total greenhouse gas emissions in 2004, this percentage reflects an enormous increase. Relative to projected direct CO{sub 2} emissions alone, the 2050 F-gas emissions will even account for ca. 7.9%. In case of CO{sub 2} mitigation, this share

  4. Evaluating 10B-enriched Boric Acid, Bromide, and Heat as Tracers of Recycled Groundwater Flow near MAR Operations

    Science.gov (United States)

    Becker, T.; Clark, J. F.

    2012-12-01

    Coupled with the unpredictability of a changing climate, the projected growth in human population over the next century requires new and innovative ways to augment already-depleted water supplies. An increasingly popular and promising development is managed aquifer recharge (MAR), a cost-effective method of intentionally storing potable water in groundwater aquifers at engineered sites worldwide. Reclaimed (or recycled) water, defined as cleaned and treated wastewater, will account for a larger portion of MAR water in future years. A crucial component for managing groundwater recharged with reclaimed water is its subsurface travel time. The California Department of Public Health (CDPH), with the most recent draft of regulations issued on November 21, 2011, requires the application of groundwater tracers to demonstrate subsurface residence time. Residence time increases the quality of reclaimed water via soil-aquifer treatment (SAT), which includes mechanisms such as sorption, biological degradation, and microbial inactivation to remove potential contaminants or pathogens. This study addresses the need for an appropriate tracer to determine groundwater residence times near MAR facilities. Standard shallow groundwater dating techniques, such as T/3He and chlorofluorocarbon (CFC) methods, cannot be used because their uncertainties are typically ± 2 years, longer than the target CDPH retention time of ~6 months. These methods also cannot map preferential flow paths. Sulfur hexafluoride (SF6), a nonreactive synthetic gas, is well-established as a deliberate tracer for determining subsurface travel time; however, SF6 is a very strong greenhouse gas and the California Air Resources Board (CARB) is regulating its emission. Other tracers, such as noble gas isotopes, that have successfully determined subsurface retention times are impractical due to their high cost. A multi-tracer experiment at the San Gabriel Spreading Grounds test basin (Montebello Forebay, Los Angeles

  5. Groundwater residence times in Shenandoah National Park, Blue Ridge Mountains, Virginia, USA: A multi-tracer approach

    Science.gov (United States)

    Plummer, L.N.; Busenberg, E.; Böhlke, J.K.; Nelms, D.L.; Michel, R.L.; Schlosser, P.

    2001-01-01

    Chemical and isotopic properties of water discharging from springs and wells in Shenandoah National Park (SNP), near the crest of the Blue Ridge Mountains, VA, USA were monitored to obtain information on groundwater residence times. Investigated time scales included seasonal (wet season, April, 1996; dry season, August-September, 1997), monthly (March through September, 1999) and hourly (30-min interval recording of specific conductance and temperature, March, 1999 through February, 2000). Multiple environmental tracers, including tritium/helium-3 (3H/3He), chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), sulfur-35 (35S), and stable isotopes (??18O and ??2H) of water, were used to estimate the residence times of shallow groundwater discharging from 34 springs and 15 wells. The most reliable ages of water from springs appear to be based on SF6 and 3H/3He, with most ages in the range of 0-3 years. This range is consistent with apparent ages estimated from concentrations of CFCs; however, CFC-based ages have large uncertainties owing to the post-1995 leveling-off of the CFC atmospheric growth curves. Somewhat higher apparent ages are indicated by 35S (> 1.5 years) and seasonal variation of ??18O (mean residence time of 5 years) for spring discharge. The higher ages indicated by the 35S and ??18O data reflect travel times through the unsaturated zone and, in the case of 35S, possible sorption and exchange of S with soils or biomass. In springs sampled in April, 1996, apparent ages derived from the 3H/3He data (median age of 0.2 years) are lower than those obtained from SF6 (median age of 4.3 years), and in contrast to median ages from 3H/3He (0.3 years) and SF6 (0.7 years) obtained during the late summer dry season of 1997. Monthly samples from 1999 at four springs in SNP had SF6 apparent ages of only 1.2 to 2.5 ?? 0.8 years, and were consistent with the 1997 SF6 data. Water from springs has low excess air (0-1 cm3 kg-1) and N2-Ar temperatures that vary

  6. Preparing for climate change.

    Science.gov (United States)

    Holdgate, M

    1989-01-01

    chlorofluorocarbons (CFCs) have been released in great quantities through their use in aerosol sprays, refrigerator fluids, and insulating foams. We can get rid of CFCs and curb the pollutants generating ozone, but it will be difficult to put the brake on either methane or nitrous oxide. And the reduction in carbon dioxide emissions will demand major changes in energy policy as well as action to slow deforestation. It appears that we are already committed to rising temperatures and sea levels. The question is by how much, in which areas? A number of things can be done to prepare for these changes: Governments must recognize that there is a problem; Better models must be worked out, especially to define where the greatest impacts from climate change and sea level rise will hit; Reference scenarios must be developed to see what the impacts are likely to be in ecological, agricultural, social and economic terms; Every country should develop "avoidance strategies" to minimize risk (for example, by not building on land likely to be flooded); We must cut down on the amount of greenhouse gases released into the atmosphere from human activities, by eliminating CFCs and adopting energy conservation programs and other measures to minimize CO2 release; Global agreements to protect the atmosphere are needed.

  7. Chemical Characteristics of Continental Outflow Over the Tropical South Atlantic Ocean from Brazil and Africa

    Science.gov (United States)

    Talbot, R. W.; Bradshaw, J. D.; Sandholm, S. T.; Smyth, S.; Blake, D. R.; Blake, N. R.; Sachse, G. W.; Collins, J. E.; Heikes, B. G.; Anderson, B. E.; Gregory, G. L.; Singh, H. B.; Lefer, B. L.; Bachmeier, A. S.

    1996-01-01

    The chemical characteristics of air parcels over the tropical South Atlantic during September - October 1992 are summarized by analysis of aged marine and continental outflow classifications. Positive correlations between CO and CH3CL and minimal enhancements of C2CL40, and various ChloroFluoroCarbon (CFC) species in air parcels recently advected over the South Atlantic basin strongly suggest an impact on tropospheric chemistry from biomass burning on adjacent continental areas of Brazil and Africa. Comparison of the composition of aged Pacific air with aged marine air over the South Atlantic basin from 0.3 to 12.5 km altitude indicates potential accumulation of long-lived species during the local dry season. This may amount to enhancements of up to two-fold for C2H6, 30% for CO, and 10% for CH3Cl. Nitric oxide and NO(x) were significantly enhanced (up to approx. 1 part per billion by volume (ppbv)) above 10 km altitude and poorly correlated with CO and CH3Cl. In addition, median mixing ratios of NO and NO(x) were essentially identical in aged marine and continental outflow air masses. It appears that in addition to biomass burning, lightning or recycled reactive nitrogen may be an important source of NO(x) to the upper troposphere. Methane exhibited a monotonic increase with altitude from approx. 1690 to 1720 ppbv in both aged marine and continental outflow air masses. The largest mixing ratios in the upper troposphere were often anticorrelated with CO, CH3Cl, and CO2, suggesting CH, contributions from natural sources. We also argue, based on CH4/CO ratios and relationships with various hydrocarbon and CFC species, that inputs from biomass burning and the northern hemisphere are unlikely to be the dominant sources of CO, CH4 and C2H6 in aged marine air. Emissions from urban areas would seem to be necessary to account for the distribution of at least CH4 and C2H6. Over the African and South American continents an efficient mechanism of convective vertical transport

  8. Observed and simulated time evolution of HCl, ClONO2, and HF total column abundances

    Directory of Open Access Journals (Sweden)

    B.-M. Sinnhuber

    2012-04-01

    Full Text Available Time series of total column abundances of hydrogen chloride (HCl, chlorine nitrate (ClONO2, and hydrogen fluoride (HF were determined from ground-based Fourier transform infrared (FTIR spectra recorded at 17 sites belonging to the Network for the Detection of Atmospheric Composition Change (NDACC and located between 80.05° N and 77.82° S. By providing such a near-global overview on ground-based measurements of the two major stratospheric chlorine reservoir species, HCl and ClONO2, the present study is able to confirm the decrease of the atmospheric inorganic chlorine abundance during the last few years. This decrease is expected following the 1987 Montreal Protocol and its amendments and adjustments, where restrictions and a subsequent phase-out of the prominent anthropogenic chlorine source gases (solvents, chlorofluorocarbons were agreed upon to enable a stabilisation and recovery of the stratospheric ozone layer. The atmospheric fluorine content is expected to be influenced by the Montreal Protocol, too, because most of the banned anthropogenic gases also represent important fluorine sources. But many of the substitutes to the banned gases also contain fluorine so that the HF total column abundance is expected to have continued to increase during the last few years. The measurements are compared with calculations from five different models: the two-dimensional Bremen model, the two chemistry-transport models KASIMA and SLIMCAT, and the two chemistry-climate models EMAC and SOCOL. Thereby, the ability of the models to reproduce the absolute total column amounts, the seasonal cycles, and the temporal evolution found in the FTIR measurements is investigated and inter-compared. This is especially interesting because the models have different architectures. The overall agreement between the measurements and models for the total column abundances and the seasonal cycles is good. Linear trends of HCl, ClONO2, and HF are calculated from both

  9. Influence of the meteorological parameters on CFCs and SF6 concentration in the air of Krakow, Poland

    Science.gov (United States)

    Bielewski, Jarosław; Najman, Joanna; Śliwka, Ireneusz; Bartyzel, Jakub; Rosiek, Janusz

    2013-04-01

    key words: gas chromatography, trace gases, CFCs and SF6 measurements in urban area. Halogenated compounds (chlorofluorocarbons-CFCs), both natural and industrial, so-called freons, currently exist as trace gases in the entire human environment. The CFCs cause ozone depletion in the stratosphere. Moreover CFCs and SF6 take part in intensification of the greenhouse effect. The decisions of the Vienna Convention (1985) and of the Montreal Protocol (1987) limited the world production level of CFCs in the year 1989 at least 35% after 2004, 90% after 2015 and total reduction after year 2030. On account of international agreements, the measurements of CFCs and SF6 in air were started. Measurement "clean" stations were situated at places outside of urban areas influence and gathered on world program - AGAGE (Advanced Global Atmospheric Gases Experiment). One of these stations is Mace Head (Ireland, 53o N, 10o W), which participates in AGAGE since 1987 [1] and in European InGOS (Integrated non-CO2 Greenhouse gas Observing System) program since 2011. Similar research is also conducted in Central Europe, in urban area of Krakow (Poland, 50o N, 19o E) since 1997. The work discusses results from 15 years of concentration measurements (in the years 1997-2012) of selected halocarbons and SF6 in Krakow. To obtain concentrations of measured compounds the mathematical procedure has been used, where concentrations were calculated using a five points Lagrange's interpolation method. Using temporary measurement data were determined daily arithmetic means and their standard deviations. Based on these data, efficiency of Montreal Protocol legislation, implemented in Poland (The Journal of Laws No. 52) could be assessed [2]. Additionally cut-off filtration method was used to estimate trend of the base line of individual air pollutant. Rejected exceedances of base lines were corelated with meteorological characteristics of Krakow region to evaluate possible sources of pollution. The

  10. Exploring Hydrofluorocarbons as Groundwater Age Tracers (Invited)

    Science.gov (United States)

    Haase, K. B.; Busenberg, E.; Plummer, L. N.; Casile, G.; Sanford, W. E.

    2013-12-01

    Groundwater dating tracers are an essential tool for analyzing hydrologic conditions in groundwater systems. Commonly used tracers for dating post-1940's groundwater include sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs), 3H-3He, and other isotopic tracers (85Kr, δ2H and δ18O isotopes, etc.). Each tracer carries a corresponding set of advantages and limitations imposed by field, analytical, and interpretive methods. Increasing the number available tracers is appealing, particularly if they possess inert chemical properties and unique temporal emission histories from other tracers. Atmospherically derived halogenated trace gases continue to hold untapped potential for new tracers, as they are generally inert and their emission histories are well documented. SF5CF3, and CFC-13 were previously shown to have application as dating tracers, though their low mixing ratios and low solubility require large amounts of water to be degassed for their quantification. Two related groups of compounds, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are hypothesized to be potential age tracers, having similar mixing ratios to the CFCs and relatively high solubility. However, these compounds yield gas chromatography electron capture detector (GC-ECD) responses that are 10-2 -10-5 less than CFC-12, making purge and trap or field stripping GC-ECD approaches impractical. Therefore, in order to use dissolved HCFCs and HFCs as age tracers, different approaches are needed. To solve this problem, we developed an analytical method that uses an atomic emission detector (GC-AED) in place of an ECD to detect fluorinated compounds. In contrast to the ECD, the AED is a universally sensitive, highly linear, elementally specific detector. The new GC-AED system is being used to measure chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), and other fluorinated compounds in one liter water samples to study their potential as age dating tracers. HCFC-22 is a

  11. Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions

    Directory of Open Access Journals (Sweden)

    M. von Hobe

    2012-11-01

    Full Text Available Significant reductions in stratospheric ozone occur inside the polar vortices each spring when chlorine radicals produced by heterogeneous reactions on cold particle surfaces in winter destroy ozone mainly in two catalytic cycles, the ClO dimer cycle and the ClO/BrO cycle. Chlorofluorocarbons (CFCs, which are responsible for most of the chlorine currently present in the stratosphere, have been banned by the Montreal Protocol and its amendments, and the ozone layer is predicted to recover to 1980 levels within the next few decades. During the same period, however, climate change is expected to alter the temperature, circulation patterns and chemical composition in the stratosphere, and possible geo-engineering ventures to mitigate climate change may lead to additional changes. To realistically predict the response of the ozone layer to such influences requires the correct representation of all relevant processes. The European project RECONCILE has comprehensively addressed remaining questions in the context of polar ozone depletion, with the objective to quantify the rates of some of the most relevant, yet still uncertain physical and chemical processes. To this end RECONCILE used a broad approach of laboratory experiments, two field missions in the Arctic winter 2009/10 employing the high altitude research aircraft M55-Geophysica and an extensive match ozone sonde campaign, as well as microphysical and chemical transport modelling and data assimilation. Some of the main outcomes of RECONCILE are as follows: (1 vortex meteorology: the 2009/10 Arctic winter was unusually cold at stratospheric levels during the six-week period from mid-December 2009 until the end of January 2010, with reduced transport and mixing across the polar vortex edge; polar vortex stability and how it is influenced by dynamic processes in the troposphere has led to unprecedented, synoptic-scale stratospheric regions with temperatures below the frost point; in these regions

  12. Using Acid Number as a Leading Indicator of Refrigeration and Air Conditioning System Performance

    Energy Technology Data Exchange (ETDEWEB)

    Dennis Cartlidge; Hans Schellhase

    2003-07-31

    This report summarizes a literature review to assess the acidity characteristics of the older mineral oil and newer polyolester (POE) refrigeration systems as well as to evaluate acid measuring techniques used in other non-aqueous systems which may be applicable for refrigeration systems. Failure in the older chlorofluorocarbon/hydrochlorofluorocarbon (CFC/HCFC) / mineral oil systems was primarily due to thermal degradation of the refrigerant which resulted in the formation of hydrochloric and hydrofluoric acids. These are strong mineral acids, which can, over time, severely corrode the system metals and lead to the formation of copper plating on iron surfaces. The oil lubricants used in the older systems were relatively stable and were not prone to hydrolytic degradation due to the low solubility of water in oil. The refrigerants in the newer hydrofluorocarbon (HFC)/POE systems are much more thermally stable than the older CFC/HCFC refrigerants and mineral acid formation is negligible. However, acidity is produced in the new systems by hydrolytic decomposition of the POE lubricants with water to produce the parent organic acids and alcohols used to prepare the POE. The individual acids can therefore vary but they are generally C5 to C9 carboxylic acids. Organic acids are much weaker and far less corrosive to metals than the mineral acids from the older systems but they can, over long time periods, react with metals to form carboxylic metal salts. The salts tend to accumulate in narrow areas such as capillary tubes, particularly if residual hydrocarbon processing chemicals are present in the system, which can lead to plugging. The rate of acid production from POEs varies on a number of factors including chemical structure, moisture levels, temperature, acid concentration and metals. The hydrolysis rate of reaction can be reduced by using driers to reduce the free water concentration and by using scavenging chemicals which react with the system acids. Total acid

  13. Atmospheric and land surface measurements in a prototype hydrologic observatory

    Science.gov (United States)

    Scanlon, B.; Krajewski, W.; Famiglietti, J.; Duffy, C.

    2003-12-01

    Quantifying spatial and temporal variability in fluxes across interfaces and storage within reservoirs is critical for understanding the water cycle. The interfaces being considered in this presentation on the Neuse basin prototype hydrologic observatory (HO) include the land surface - atmosphere and land surface - groundwater. Critical fluxes include precipitation, infiltration, evapotranspiration and energy balance, and groundwater recharge; soil water storage in the unsaturated zone is an important determinant of flux partitioning at either interface. A companion presentation in this session (Genereux et al.) focuses on fluxes of water and solutes related to groundwater-surface water interfaces and surface water flow. The proposed measurement approach combines remote sensing and in-situ measurements to cover a wide range in spatial (1 m2 - 10,000 km2) scales. High-resolution precipitation maps will be provided by a combination of NEXRAD data and an enhanced ground-based network of rain gauges, disdrometers, and profilers. Evapotranspiration and energy balance fluxes will be monitored at several locations to characterize spatial patterns and process controls. Measurements of water content and matric potential will be co-located in the unsaturated zone to develop in situ water retention functions and to test existing pedotransfer functions for translating basic soils data to hydraulic parameters for modeling. Subsurface water fluxes in the unsaturated zone will also be estimated using newly developed fluxmeters. Co-located unsaturated and saturated zone instrumentation will be used to measure vertical and horizontal gradients to determine flux direction and to quantify fluxes using modeling. Fluxes in the unsaturated zone below the root zone may be equated to groundwater recharge. In addition, environmental tracers (tritium/helium and chlorofluorocarbons) will be measured in groundwater to estimate recharge rates. Ground-based measurements will be located in

  14. Clinical effectiveness of the Respimat® inhaler device in managing chronic obstructive pulmonary disease: evidence when compared with other handheld inhaler devices

    Directory of Open Access Journals (Sweden)

    et al

    2011-02-01

    Full Text Available Felix SF Ram1, Celso R Carvallho2, John White31School of Health and Social Services, Massey University, Auckland, New Zealand; 2Department of Physical Therapy, School of Medicine, University of São Paulo, Brazil; 3York Hospitals NHS Foundation Trust, York Hospital, York, UKObjectives: Medication for the management of chronic obstructive pulmonary disease (COPD may be delivered by a number of different inhaler devices. This study was undertaken to determine the clinical effectiveness of the Respimat® handheld inhaler device compared with other handheld inhaler devices for the delivery of medication in stable COPD.Methodology: A systematic review of high-quality randomized controlled clinical trials comparing Respimat with other inhaler devices using the same medication was performed. Studies were searched for in the Cochrane Central Register of Controlled Trials as well as other relevant electronic databases. Manufacturers of inhaled COPD medication were also contacted for potential trials.Results: Seven studies of high methodological quality with 3813 participants were included in the review. Three trials used Handihaler® as the comparator inhaler, three used a chlorofluorocarbon metered-dose inhaler (CFC-MDI, and one trial used a hydroflouroalkane (HFA-MDI. When Respimat was compared with Handihaler, the following reported outcomes were not significantly different: trough forced expiratory volume in 1 second (FEV1 (weighted mean difference [WMD] 0.01 L; P = 0.14, trough forced vital capacity (FVC (WMD 0.001 L: P = 0.88, peak FEV1 (WMD 0.01 L: P = 0.08, peak FVC (WMD 0.01 L: P = 0.55, morning peak expiratory flow rate (PEFR (WMD 5.06 L/min: P = 0.08, and evening PEFR (WMD 4.39 L/min: P = 0.15. Furthermore, there were no differences when Respimat was compared with Handihaler for risk of exacerbations (relative risk [RR] 0.94: P = 0.81, dry mouth (RR 1.57: P = 0.34, or nasopharyngitis (RR 1.42: P = 0.22. For Respimat compared with CFC-MDI, the

  15. Hydrogeologic setting and simulation of groundwater flow near the Canterbury and Leadville Mine Drainage Tunnels, Leadville, Colorado

    Science.gov (United States)

    Wellman, Tristan P.; Paschke, Suzanne S.; Minsley, Burke; Dupree, Jean A.

    2011-01-01

    -current resistivity field survey was performed to evaluate the geologic structure of the study area. The results show that the Canterbury Tunnel is located in a downthrown structural block that is not in direct physical connection with the Leadville Mine Drainage Tunnel. The presence of this structural discontinuity implies there is no direct groundwater pathway between the tunnels along a laterally continuous bedrock unit. Water-quality results for pH and major-ion concentrations near the Canterbury Tunnel showed that acid mine drainage has not affected groundwater quality. Stable-isotope ratios of hydrogen and oxygen in water indicate that snowmelt is the primary source of groundwater recharge. On the basis of chlorofluorocarbon and tritium concentrations and mixing ratios for groundwater samples, young groundwater (groundwater recharged after 1953) was indicated at well locations upgradient from and in a fault block separate from the Canterbury Tunnel. Samples from sites downgradient from the Canterbury Tunnel were mixtures of young and old (pre-1953) groundwater and likely represent snowmelt recharge mixed with older regional groundwater that discharges from the bedrock units to the Arkansas River valley. Discharge from the Canterbury Tunnel contained the greatest percentage of old (pre-1953) groundwater with a mixture of about 25 percent young water and about 75 percent old water. A calibrated three-dimensional groundwater model representing high-flow conditions was used to evaluate large-scale flow characteristics of the groundwater and to assess whether a substantial hydraulic connection was present between the Canterbury Tunnel and Leadville Mine Drainage Tunnel. As simulated, the faults restrict local flow in many areas, but the fracture-damage zones adjacent to the faults allow groundwater to move along faults. Water-budget results indicate that groundwater flow across the lateral edges of the model controlled the majority of flow in and out of the aquifer (79 percent and

  16. Accuracy of CFC groundwater dating in a crystalline bedrock aquifer: Data from a site in southern Sweden

    Science.gov (United States)

    Bockgård, Niclas; Rodhe, Allan; Olsson, K. A.

    The concentrations of chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) and tritium were determined in groundwater in fractured crystalline bedrock at Finnsjön, Sweden. The specific goal was to investigate the accuracy of CFC dating in such an environment, taking potential degradation and mixing of water into consideration. The water was sampled to a depth of 42 m in three boreholes along an 800-m transect, from a recharge area to a local discharge area. The CFC-113 concentration was at the detection limit in most samples. The apparent recharge date obtained from CFC-11 was earlier than from CFC-12 for all samples, with a difference of over 20 years for some samples. The difference was probably caused by degradation of CFC-11. The CFC-12 dating of the samples ranged from before 1945 to 1975, with the exception of a sample from the water table, which had a present-day concentration. Conclusions about flow paths or groundwater velocity could not be drawn from the CFCs. The comparison between CFC-12 and tritium concentrations showed that most samples could be unmixed or mixtures of waters with different ages, and the binary mixtures that matched the measured concentrations were determined. The mixing model approach can be extended with additional tracers. Précision de la datation au CFC dans un aquifère rocheux-fracturé: données d'un site du sud de la Suède. Les concentrations en chlorofluorocarbones (CFC-11, CFC-12, CFC-113) et entritium ont été déterminées dans l'eau souterraine d'un massif fracturé à Finnsjön en Suède. Le but de cette étude est de mieux cerner la précision de la méthode de datation au CFC dans ce type d'environnement hydrogéologique, tout en considérant d'éventuels phénomènes de dégradation et de mélange d'eaux. L'eau a été échantillonnée à une profondeur de 42 mètres dans trois forages alignés sur 800 mètres entre une zone de recharge et une zone de déversement. Les concentrations en CFC-113 sont dans la plupart

  17. Hydrosalinity studies of the Virgin River, Dixie Hot Springs, and Littlefield Springs, Utah, Arizona, and Nevada

    Science.gov (United States)

    Gerner, Steven J.; Thiros, Susan A.; Gerner, Steven J.; Thiros, Susan A.

    2014-01-01

    in the Virgin River Gorge containing known fault zones accounted for about 48 percent of this total seepage loss. An additional seepage loss of 6.7 ft3/s was calculated for the reach of the Virgin River between Bloomington, Utah, and the Utah/Arizona State line. This loss in flow is small compared to total flow in the river and is comparable to the rated error in streamflow measurements in this reach; consequently, it should be used with caution. Littlefield Springs were studied to determine the fraction of its discharge that originates as upstream seepage from the Virgin River and residence time of this water in the subsurface. Geochemical and environmental tracer data from groundwater and surface-water sites in the Virgin River Gorge area suggest that discharge from Littlefield Springs is a mixture of modern (post-1950s) seepage from the Virgin River upstream of the springs and older groundwater from a regional carbonate aquifer. Concentrations of the chlorofluorocarbons (CFCs) CFC-12 and CFC-113, chloride/fluoride and chloride/bromide ratios, and the stable isotope deuterium indicate that water discharging from Littlefield Springs is about 60 percent seepage from the Virgin River and about 40 percent discharge from the regional carbonate aquifer. The river seepage component was determined to have an average subsurface traveltime of about 26 ±1.6 years before discharging at Littlefield Springs. Radiocarbon data for Littlefield Springs suggest groundwater ages from 1,000 to 9,000 years. Because these are mixed waters, the component of discharge from the carbonate aquifer is likely much older than the groundwater ages suggested by the Littlefield Springs samples. If the dissolved-solids load from Dixie Hot Springs to the Virgin River were reduced, the irrigation water subsequently applied to agricultural fields in the St. George and Washington areas, which originates as water from the Virgin River downstream of Dixie Hot Springs, would have a lower dissolved

  18. Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

    2016-10-19

    ) closed-basin lake-level changes reflected groundwater-level changes in the Quaternary, Prairie du Chien, and Jordan aquifers; (3) the installation of outlet-control structures, such as culverts and weirs, resulted in smaller multiyear lake-level changes than lakes without outlet-control structures; (4) water levels in lakes primarily overlying Superior Lobe deposits were significantly more variable than lakes primarily overlying Des Moines Lobe deposits; (5) lake-level declines were larger with increasing mean lake-level elevation; and (6) the frequency of some of these characteristics varies by landscape position. Flow-through lakes and lakes with outlet-control structures were more common in watersheds with more than 50 percent urban development compared to watersheds with less than 50 percent urban development. A comparison of two 35-year periods during 1925–2014 revealed that variability of annual mean lake levels in flow-through lakes increased when annual precipitation totals were more variable, whereas variability of annual mean lake levels in closed-basin lakes had the opposite pattern, being more variable when annual precipitation totals were less variable. Oxygen-18/oxygen-16 and hydrogen-2/hydrogen-1 ratios for water samples from 40 wells indicated the well water was a mixture of surface water and groundwater in 31 wells, whereas ratios from water sampled from 9 other wells indicated that water from these wells receive no surface-water contribution. Of the 31 wells with a mixture of surface water and groundwater, 11 were downgradient from White Bear Lake, likely receiving water from deeper parts of the lake. Age dating of water samples from wells indicated that the age of water in the Prairie du Chien and Jordan aquifers can vary widely across the northeast Twin Cities Metropolitan Area. Estimated ages of recharge for 9 of the 40 wells sampled for chlorofluorocarbon concentrations ranged widely from the early 1940s to mid-1970s. The wide range in estimated

  19. Geochemical Investigation of the Arbuckle-Simpson Aquifer, South-Central Oklahoma, 2004-06

    Science.gov (United States)

    Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.

    2009-01-01

    dolomite. The major ion chemistry for these 34 samples is consistent with a set of water-rock interactions. Rainfall infiltrates the soil zone, where the host rock, limestone or dolomite, dissolves as a result of uptake of carbon dioxide gas. Some continued dissolution of dolomite and precipitation of calcite occur as the water flows through the saturated zone. The major ion chemistry of the two samples from wells completed in the confined part of the aquifer indicates the water is a sodium chloride type. Geochemical inverse modeling determined that mixing of calcite-saturated recharge water with brine and dissolving calcite, dolomite, and gypsum accounts for the water composition of these two samples. One of the two samples, collected at Vendome Well in Chickasaw National Recreation Area, had a mixing fraction of brine of about 1 percent. The brine component of the sample at Vendome Well is likely to account for the relatively large concentrations of many of the trace elements (potassium, fluoride, bromide, iodide, ammonia, arsenic, boron, lithium, selenium, and strontium) measured in the water sample. Carbon-14, helium-3/tritium, and chlorofluorocarbons were used to calculate ground-water ages, recharge temperatures, and mixtures of ground water in the Arbuckle-Simpson aquifer. Thirty four of 36 water samples recharged the aquifer after 1950, indicating that water is moving quickly from recharge areas to discharge at streams and springs. Two exceptions to this classification were noted in samples 6 and 15 (Vendome Well). Ground-water ages determined for these two samples by using carbon-14 are 34,000 years (site 6) and 10,500 years (site 15). Concentrations of dissolved argon, neon, and xenon in water samples were used to determine the temperature of the water when it recharged the aquifer. The mean annual air temperature at Ada, Oklahoma, is 16 degrees Celsius (C) and the median temperature of the 30 reconnaissance water samples was 18.1 C. The av

  20. Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact

    Science.gov (United States)

    Scheeren, H. A.

    2003-09-01

    special interest in this thesis are the tropical regions because they are becoming increasingly important in terms of global anthropogenic pollution and climate change. In addition, natural emissions of hydrocarbons (notably isoprene and terpenes from plants) and reactive chlorocarbons appear to be concentrated in the tropics, where the largest uncertainties exist with respect to source type and source strength. Whenever available, the reactive NMHC and chlorocarbon data have been analyzed with the help of concurrent measurements, which includes ozone (O3), carbon monoxide (CO), nitrogen oxide (NO), total reactive oxidized nitrogen (NOy), nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN), the chlorofluorocarbons CFC-11 (CCl3F) and CFC-12 (CCl2F2), the hydrofluorocarbon HFC-134a (CH2FCF3), and the hydrochlorofluorocarbons HCFC-141b (CH3CCl2F) and HCFC-142b (CH3CClF2). These additional measurements provided important information about the air mass origin, pollution sources, and chemical age of the encountered air masses. The STREAM-measurements contribute to the present understanding of the budgets of reactive organic trace species in the mid-latitude lower stratosphere at different seasonal conditions. It was found that during summer and fall, the mean concentrations of reactive NMHC and acetone in the lower stratosphere were a factor of two or more higher than during winter, as a result of more intense and frequent mixing across the tropopause. The role of tropical emissions in the global budget of hydrocarbons and the chlorocarbons CH3Cl, CH2Cl2, CHCl3, and C2Cl4 has been investigated during the LBA/CLAIRE 1998, INDOEX 1999 and MINOS 2001 campaigns. The INDOEX measurements over the Indian Ocean showed that strongly enhanced CH3Cl and related combustion tracers, such as CO, hydrocarbons and CH3CN in polluted air masses from India and Southeast Asia, relate to the extensive use of biofuels (notably the

  1. First retrievals of HCFC-142b from ground-based high-resolution FTIR solar observations: application to high-altitude Jungfraujoch spectra

    Science.gov (United States)

    Mahieu, Emmanuel; O'Doherty, Simon; Reimann, Stefan; Vollmer, Martin; Bader, Whitney; Bovy, Benoît; Lejeune, Bernard; Demoulin, Philippe; Roland, Ginette; Servais, Christian; Zander, Rodolphe

    2013-04-01

    Hydrofluorocarbons (HCFCs) are the first substitutes to the long-lived ozone depleting halocarbons, in particular the chlorofluorocarbons (CFCs). Given the complete ban of the CFCs by the Montreal Protocol, its Amendments and Adjustments, HCFCs are on the rise, with current rates of increase substantially larger than at the beginning of the 21st century. HCFC-142b (CH3CClF2) is presently the second most abundant HCFCs, after HCFC-22 (CHClF2). It is used in a wide range of applications, including as a blowing foam agent, in refrigeration and air-conditioning. Its concentration will soon reach 25 ppt in the northern hemisphere, with mixing ratios increasing at about 1.1 ppt/yr [Montzka et al., 2011]. The HCFC-142b lifetime is estimated at 18 years. With a global warming potential of 2310 on a 100-yr horizon, this species is also a potent greenhouse gas [Forster et al., 2007]. First space-based retrievals of HCFC-142b have been reported by Dufour et al. [2005]. 17 occultations recorded in 2004 by the Canadian ACE-FTS instrument (Atmospheric Chemistry Experiment - Fourier Transform Spectrometer, onboard SCISAT-1) were analyzed, using two microwindows (1132.5-1135.5 and 1191.5-1195.5 cm-1). In 2009, Rinsland et al. determined the HCFC-142b trend near the tropopause, from the analysis of ACE-FTS observations recorded over the 2004-2008 time period. The spectral region used in this study extended from 903 to 905.5 cm-1. In this contribution, we will present the first HCFC-142b measurements from ground-based high-resolution Fourier Transform Infrared (FTIR) solar spectra. We use observations recorded at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl), with a Bruker 120HR instrument, in the framework of the Network for the Detection of Atmospheric Composition Change (NDACC, visit http://www.ndacc.org). The retrieval of HCFC-142b is very challenging, with simulations indicating only weak absorptions, lower than 1% for low sun spectra and current

  2. Potencial de emissão de metano em lavouras de arroz irrigado Methane emission potential in flooded rice fields

    Directory of Open Access Journals (Sweden)

    Dirceu Agostinetto

    2002-12-01

    responsible for such phenomenon. The main gases that cause the greenhouse effect are carbon dioxide (CO2, methane (CH4, nitrous oxide (N2O, and chlorofluorocarbons (CFCs. Methane stands out amongst them by the amount produced and by its activity in the absorbing atmospheric heat. The main methane producing sources are soils naturally flooded or cultivated under flooding conditions, which represent approximately 40% of the total methane emitted; from this amount, 37% is emitted by rice cultivated under flooding conditions. In this context, the present review has as main purposes to describe processes responsible for methane production and emission, as well as to discuss management practices and rice plant characteristics which affect emission of this gas. From the total methane originated in rice fields during its growth cycle, between 60 to 90% comes from rice plants. Although methane is not the main gas responsible for the greenhouse effect and rice crop does not represent the main methane source, the reduction in the emission could be accomplished through changes in rice cultural practices. Amongst alternatives that can be worked out are management of irrigation water and fertilizer applied, and cropping of rice cultivars that present lower number of aerenchyma and lower biomass production, whereas maintaining rice grain yields potential.

  3. The Greenhouse effect: impacts of ultraviolet-B (UV-B) radiation, carbon dioxide (CO2), and ozone (O3) on vegetation.

    Science.gov (United States)

    Krupa, S V; Kickert, R N

    1989-01-01

    There is a fast growing and an extremely serious international scientific, public and political concern regarding man's influence on the global climate. The decrease in stratospheric ozone (O3) and the consequent possible increase in ultraviolet-B (UV-B) is a critical issue. In addition, tropospheric concentrations of 'greenhouse gases' such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) are increasing. These phenomena, coupled with man's use of chlorofluorocarbons (CFCs), chlorocarbons (CCs), and organo-bromines (OBs) are considered to result in the modification of the earth's O3 column and altered interactions between the stratosphere and the troposphere. A result of such interactions could be the global warming. As opposed to these processes, tropospheric O3 concentrations appear to be increasing in some parts of the world (e.g. North America). Such tropospheric increases in O3 and particulate matter may offset any predicted increases in UV-B at those locations. Presently most general circulation models (GCMs) used to predict climate change are one- or two-dimensional models. Application of satisfactory three-dimensional models is limited by the available computer power. Recent studies on radiative cloud forcing show that clouds may have an excess cooling effect to compensate for a doubling of global CO2 concentrations. There is a great deal of geographic patchiness or variability in climate. Use of global level average values fails to account for this variability. For example, in North America: 1. there may be a decrease in the stratospheric O3 column (1-3%); however, there appears to be an increase in tropospheric O3 concentrations (1-2%/year) to compensate up to 20-30% loss in the total O3 column; 2. there appears to be an increase in tropospheric CO2, N2O and CH4 at the rate of roughly 0.8%, 0.3% and 1-2%, respectively, per year; 3. there is a decrease in erythemal UV-B; and 4. there is a cooling of tropospheric air temperature due to

  4. Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

    2016-10-19

    ) closed-basin lake-level changes reflected groundwater-level changes in the Quaternary, Prairie du Chien, and Jordan aquifers; (3) the installation of outlet-control structures, such as culverts and weirs, resulted in smaller multiyear lake-level changes than lakes without outlet-control structures; (4) water levels in lakes primarily overlying Superior Lobe deposits were significantly more variable than lakes primarily overlying Des Moines Lobe deposits; (5) lake-level declines were larger with increasing mean lake-level elevation; and (6) the frequency of some of these characteristics varies by landscape position. Flow-through lakes and lakes with outlet-control structures were more common in watersheds with more than 50 percent urban development compared to watersheds with less than 50 percent urban development. A comparison of two 35-year periods during 1925–2014 revealed that variability of annual mean lake levels in flow-through lakes increased when annual precipitation totals were more variable, whereas variability of annual mean lake levels in closed-basin lakes had the opposite pattern, being more variable when annual precipitation totals were less variable. Oxygen-18/oxygen-16 and hydrogen-2/hydrogen-1 ratios for water samples from 40 wells indicated the well water was a mixture of surface water and groundwater in 31 wells, whereas ratios from water sampled from 9 other wells indicated that water from these wells receive no surface-water contribution. Of the 31 wells with a mixture of surface water and groundwater, 11 were downgradient from White Bear Lake, likely receiving water from deeper parts of the lake. Age dating of water samples from wells indicated that the age of water in the Prairie du Chien and Jordan aquifers can vary widely across the northeast Twin Cities Metropolitan Area. Estimated ages of recharge for 9 of the 40 wells sampled for chlorofluorocarbon concentrations ranged widely from the early 1940s to mid-1970s. The wide range in estimated

  5. Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington

    Science.gov (United States)

    Snyder, D.T.; Wilkinson, J.M.; Orzol, L.L.

    1996-01-01

    public-supply wells in Clark County may be receiving a component of water that recharged in areas that are more conducive to contaminant entry. The aquifer sensitivity maps illustrate a critical deficiency in the DRASTIC methodology: the failure to account for the dynamics of the ground-water flow system. DRASTIC indices calculated for a particular location thus do not necessarily reflect the conditions of the ground-water resources at the recharge areas to that particular location. Each hydrogeologic unit was also mapped to highlight those areas that will eventually receive flow from recharge areas with on-site waste-disposal systems. Most public-supply wells in southern Clark County may eventually receive a component of water that was recharged from on-site waste-disposal systems.Traveltimes from particle tracking were used to estimate the minimum and maximum age of ground water within each model-grid cell. Chlorofluorocarbon (CFC)-age dating of ground water from 51 wells was used to calibrate effective porosity values used for the particle- tracking program by comparison of ground-water ages determined through the use of the CFC-age dating with those calculated by the particle- tracking program. There was a 76 percent agreement in predicting the presence of modern water in the 51 wells as determined using CFCs and calculated by the particle-tracking program. Maps showing the age of ground water were prepared for all the hydrogeologic units. Areas with the youngest ground-water ages are expected to be at greatest risk for contamination from anthropogenic sources. Comparison of these maps with maps of public- supply wells in Clark County indicates that most of these wells may withdraw ground water that is, in part, less than 100 years old, and in many instances less than 10 years old. Results of the analysis showed that a single particle-tracking analysis simulating advective transport can be used to evaluate ground-water vulnerability for any part of a ground-wate

  6. Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida

    Science.gov (United States)

    Katz, Brian G.; Hornsby, H.D.; Bohlke, J.F.; Mokray, M.F.

    1999-01-01

    A multi-tracer approach, which consisted of analyzing water samples for n aturally occurring chemical and isotopic indicators, was used to better understand sources and chronology of nitrate contamination in spring wate rs discharging to the Suwannee and Santa Fe Rivers in northern Florida. Dur ing 1997 and 1998, as part of a cooperative study between the Suwannee River Water Management District and the U.S. Geological Survey, water samples were collected and analyzed from 24 springs and two wells for major ions, nutrients, dissolved organic carbon, and selected environmental isotopes [18O/16O, D/H, 13C/12C, 15N/14N]. To better understand when nitrate entered the ground-water system, water samples were analyzed for chlorofluorocarbons (CFCs; CCl3F, CCl2F2, and C2Cl3F3) and tritium (3H); in this way, the apparent ages and residence times of spring waters and water from shallow zones in the Upper Floridan aquifer were determined. In addition to information obtained from the use of isotopic and other chemical tracers, information on changes in land-use activities in the basin during 1954-97 were used to estimate nitrogen inputs from nonpoint sources for five counties in the basin. Changes in nitrate concentrations in spring waters with time were compared with estimated nitrogen inputs for Lafayette and Suwannee Counties. Agricultural activities [cropland farming, animal farming operations (beef and dairy cows, poultry, and swine)] along with atmospheric deposition have contributed large quantities of nitrogen to ground water in the Suwannee River Basin in northern Florida. Changes in agricultural land use during the past 40 years in Alachua, Columbia, Gilchrist, Lafayette, and Suwannee Counties have contributed variable amounts of nitrogen to the ground-water system. During 1955-97, total estimated nitrogen from all nonpoint sources (fertilizers, animal wastes, atmospheric deposition, and septic tanks) increased continuously in Gilchrist and Lafayette Counties. In

  7. Electrostatic charges generated on aerosolisation of dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanyang

    2001-07-01

    In responding to the international community's agreement of phasing out chlorofluorocarbon (CFC) propellants by the year 2000, hydrofluoroalkane (HFA) has been chosen to replace CFCs. Intensive investigations related to the new propellant products have been carried out. Aerosol electrostatics is one of the topics investigated. To understand and subsequently control the charging processes is the motive of the research reported here. To help elucidate the complex charging process occurring naturally during atomization of liquids from pressurised Metered Dose Inhalers (pMDIs), it has been broken down into a sequence of related, simpler sub processes-drop charging, streaming current charging (coarse spray), splashing charging and fine spray charging. Our initial studies are of single drops forming at and breaking away from the tips of capillary tubes. The drop forming processes are so slow that any hydrodynamic effect can be dismissed. Then the charge on the drop is measured. It is found that the charge on water drops is always negative ({approx} 10{sup -14}C) at field-free condition and the magnitude of the charge increases as the drop size increases and the surrounding tube diameter decreases. With salt solutions, the charge on drops is negative at dilute solutions, decreases in magnitude as the concentration of electrolytes increases and finally reverses the sign of charge at approximately 1 M - drop charge becomes positive. All these experimental results can be explained in terms of contact potential between liquid and the inner wall of the capillary, which sets up an electric field between the pendant drop and the surrounding tube. Then computational simulation work is carried out and the data are compared with experimental results. It is found that the computer simulation data are in accord with experimental observations. This is a potential method to measure absolute potential difference between a liquid and a solid. Secondly, the hydrodynamic processes are

  8. ER-2 in flight

    Science.gov (United States)

    1996-01-01

    above 95 percent of the Earth's atmosphere. At this altitude the aircraft provides a stable platform for Earth imagery, atmospheric research, and electronic sensor development. Because the ER-2 can fly so high, its sensors 'mimic' sensors carried aboard orbiting satellites. For most missions the ER-2 operates at altitudes between 65,000 feet and 70,000 feet. Depending on aircraft weight, the ER-2 reaches a cruise altitude of 65,000 feet within 20 minutes. Typical cruise speed is 410 knots. The range for a normal 6-hour mission is 2,200 nautical miles (4,070 kilometers), which yields 5 hours of data collection at high altitude. The aircraft is capable of longer missions of up to 8 hours and ranges of up to 3,000 nautical miles (5,500 kilometers). The ER-2 can carry a maximum payload of 2,600 pounds (1,179 kilograms) distributed in the equipment bay, nose area, and wing pods. In 1991, NASA launched a comprehensive program to study the Earth as an environmental system, now called the Earth Science Enterprise. By using satellites and other tools like the ER-2 to intensively study the Earth, NASA hopes to expand human understanding of how natural processes affect people and how people might be affecting them. Such studies will yield improved weather forecasts, tools for managing agriculture and forests, information for fishermen and local planners, and, eventually, the ability to predict how the climate will change in the future. NASA ER-2 aircraft have played an important role in Earth Science research, like studying ozone depletion over Antarctica and the Arctic. In August and September 1987 an ER-2 traveled to Punta Arenas, Chile, to conduct overflights of the Antarctic. Results from this study provided information suggesting that human-made chemical compounds, specifically chloro-fluorocarbons, caused enormous ozone depletion over the Antarctic region. Subsequent deployments have continued the study of the production and loss of ozone in the polar stratosphere

  9. The Greenhouse effect: impacts of ultraviolet-B (UV-B) radiation, carbon dioxide (CO2), and ozone (O3) on vegetation.

    Science.gov (United States)

    Krupa, S V; Kickert, R N

    1989-01-01

    There is a fast growing and an extremely serious international scientific, public and political concern regarding man's influence on the global climate. The decrease in stratospheric ozone (O3) and the consequent possible increase in ultraviolet-B (UV-B) is a critical issue. In addition, tropospheric concentrations of 'greenhouse gases' such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) are increasing. These phenomena, coupled with man's use of chlorofluorocarbons (CFCs), chlorocarbons (CCs), and organo-bromines (OBs) are considered to result in the modification of the earth's O3 column and altered interactions between the stratosphere and the troposphere. A result of such interactions could be the global warming. As opposed to these processes, tropospheric O3 concentrations appear to be increasing in some parts of the world (e.g. North America). Such tropospheric increases in O3 and particulate matter may offset any predicted increases in UV-B at those locations. Presently most general circulation models (GCMs) used to predict climate change are one- or two-dimensional models. Application of satisfactory three-dimensional models is limited by the available computer power. Recent studies on radiative cloud forcing show that clouds may have an excess cooling effect to compensate for a doubling of global CO2 concentrations. There is a great deal of geographic patchiness or variability in climate. Use of global level average values fails to account for this variability. For example, in North America: 1. there may be a decrease in the stratospheric O3 column (1-3%); however, there appears to be an increase in tropospheric O3 concentrations (1-2%/year) to compensate up to 20-30% loss in the total O3 column; 2. there appears to be an increase in tropospheric CO2, N2O and CH4 at the rate of roughly 0.8%, 0.3% and 1-2%, respectively, per year; 3. there is a decrease in erythemal UV-B; and 4. there is a cooling of tropospheric air temperature due to

  10. Quality of water from crystalline rock aquifers in New England, New Jersey, and New York, 1995-2007

    Science.gov (United States)

    Flanagan, Sarah M.; Ayotte, Joseph D.; Robinson,, Gilpin R.

    2012-01-01

    Crystalline bedrock aquifers in New England and parts of New Jersey and New York (NECR aquifers) are a major source of drinking water. Because the quality of water in these aquifers is highly variable, the U.S. Geological Survey (USGS) statistically analyzed chemical data on samples of untreated groundwater collected from 117 domestic bedrock wells in New England, New York, and New Jersey, and from 4,775 public-supply bedrock wells in New England to characterize the quality of the groundwater. The domestic-well data were from samples collected by the USGS National Water-Quality Assessment (NAWQA) Program from 1995 through 2007. The public-supply-well data were from samples collected for the U.S. Environmental Protection Agency (USEPA) Safe Drinking Water Act (SDWA) Program from 1997 through 2007. Chemical data compiled from the domestic wells include pH, specific conductance, dissolved oxygen, alkalinity, and turbidity; 6 nitrogen and phosphorus compounds, 14 major ions, 23 trace elements, 222radon gas (radon), 48 pesticide compounds, and 82 volatile organic compounds (VOCs). Additional samples were collected from the domestic wells for the analysis of gross alpha- and gross beta-particle radioactivity, radium isotopes, chlorofluorocarbon isotopes, and the dissolved gases methane, carbon dioxide, nitrogen, and argon. Chemical data compiled from the public-supply wells include pH, specific conductance, nitrate, iron, manganese, sodium, chloride, fluoride, arsenic, uranium, radon, combined radium (226radium plus 228radium), gross alpha-particle radioactivity, and methyl tert-butyl ether (MtBE). Patterns in fluoride, arsenic, uranium, and radon distributions were discernable when the data were compared to lithology groupings of the bedrock, indicating that the type of bedrock has an effect on the quality of groundwater from NECR aquifers. Fluoride concentrations were significantly higher in groundwater samples from the alkali granite, peraluminous granite, and

  11. Hydrosalinity studies of the Virgin River, Dixie Hot Springs, and Littlefield Springs, Utah, Arizona, and Nevada

    Science.gov (United States)

    Gerner, Steven J.; Thiros, Susan A.; Gerner, Steven J.; Thiros, Susan A.

    2014-01-01

    in the Virgin River Gorge containing known fault zones accounted for about 48 percent of this total seepage loss. An additional seepage loss of 6.7 ft3/s was calculated for the reach of the Virgin River between Bloomington, Utah, and the Utah/Arizona State line. This loss in flow is small compared to total flow in the river and is comparable to the rated error in streamflow measurements in this reach; consequently, it should be used with caution. Littlefield Springs were studied to determine the fraction of its discharge that originates as upstream seepage from the Virgin River and residence time of this water in the subsurface. Geochemical and environmental tracer data from groundwater and surface-water sites in the Virgin River Gorge area suggest that discharge from Littlefield Springs is a mixture of modern (post-1950s) seepage from the Virgin River upstream of the springs and older groundwater from a regional carbonate aquifer. Concentrations of the chlorofluorocarbons (CFCs) CFC-12 and CFC-113, chloride/fluoride and chloride/bromide ratios, and the stable isotope deuterium indicate that water discharging from Littlefield Springs is about 60 percent seepage from the Virgin River and about 40 percent discharge from the regional carbonate aquifer. The river seepage component was determined to have an average subsurface traveltime of about 26 ±1.6 years before discharging at Littlefield Springs. Radiocarbon data for Littlefield Springs suggest groundwater ages from 1,000 to 9,000 years. Because these are mixed waters, the component of discharge from the carbonate aquifer is likely much older than the groundwater ages suggested by the Littlefield Springs samples. If the dissolved-solids load from Dixie Hot Springs to the Virgin River were reduced, the irrigation water subsequently applied to agricultural fields in the St. George and Washington areas, which originates as water from the Virgin River downstream of Dixie Hot Springs, would have a lower dissolved

  12. Past and future ice age initiation: the role of an intrinsic deep-ocean millennial oscillation

    Science.gov (United States)

    Johnson, R. G.

    2014-05-01

    This paper offers three interdependent contributions to studies of climate variation: (1) the recognition and analysis of an intrinsic millennial oceanic oscillation that affects both Northern and Southern high latitude climates, (2) The recognition of an oceanographic switch to ice-free seas west of Greenland that explains the initiation of the Last Ice Age, and (3) an analysis of the effect of increasing salinity in the seas east of Greenland that suggests the possibility of the initiation of an ice age threshold climate in the near future. In the first contribution the millennial oscillation in the flow of the North Atlantic Drift reported by Bond et al. (1997) is proposed to be part of a 1500 yr intrinsic deep ocean oscillation. This oscillation involves the exchange of North Atlantic intermediate-level deep water (NADW) formed in the seas east of Greenland with Antarctic Bottom Water formed in a shallow-water zone at the edge of the Antarctic continent. The concept of NADW formation is already well known, with details of the sinking water flowing out of the Greenland Sea observed by Smethie et al. (2000) using chlorofluorocarbon tracers. The concept of Antarctic Bottom Water formation is also already well established. However, its modulation by the changing fraction of NADW in the Southern Ocean, which I infer from the analysis of Weyl (1968), has not been previously discussed. The modulated lower-salinity Antarctic Bottom Water that reaches the northern North Atlantic then provides negative feedback for the cyclic variation of NADW formation as proposed here. This causes the 1500 yr bipolar oscillation. The feedback suggests the possible sinusoidal character of the proposed oscillation model. The model is consistent with the cooling of the Little Ice Age (Lamb, 1972, 1995), and it also correctly predicts NASA's observation of today's record maximum area of winter sea ice on the Southern Ocean and the present observed record low rate of Antarctic Bottom Water

  13. Tropospheric Halogen Chemistry

    Science.gov (United States)

    von Glasow, R.; Crutzen, P. J.

    2003-12-01

    processes. Early work by Cauer (1951) had shown that Cl/Na and Cl/Mg ratios were lower in air than in seawater, indicating loss of chlorine by "acid displacement" from sea salt by the strong acids, H2SO4 (Eriksson (1959a, b) and HNO3 (Robbins et al., 1959). Already the first measurements of bromine in aerosols by Duce et al. (1963) showed that bromine, like chlorine, was lost from the sea salt particles, whereas iodine was strongly enriched ( Duce et al., 1965). Research since the early 1980s has shown that photochemical processes are actively involved.Interest in the chemistry of atmospheric halogens took a steep upward surge after it was postulated that the release of industrially produced halocarbons, in particular the chlorofluorocarbons (CFCs), CFCl3, and CF2Cl2, could cause severe depletions in stratospheric ozone (Molina and Rowland, 1974) by the reactions involving the CFC photolytic product radicals, Cl and ClO, as catalysts. The first stratospheric measurements of ClO did indeed show its presence in significant quantities in the stratosphere so that by the end of the 1970s USA, Canada, and the Scandinavian countries issued laws against the use of CFC gases as propellants in spray cans. In the mid-1980s the springtime stratospheric ozone hole over Antarctica was discovered by Farman et al. (1985), involving heterogeneous reactions on polar stratospheric clouds that lead to chlorine activation ( Solomon et al., 1986). Ten years later, in 1996, a complete phaseout ofthe production of the CFCs and a number of other chlorine- or bromine-containing chemicals came into effect for all nations in the developed world. In this contribution we will, however, concentrate on the impact of reactive chlorine, bromine, and iodine on tropospheric ozone chemistry.Halogens have the potential to be important in many facets of tropospheric chemistry. A multitude of gas phase reactions and gas-particle interactions occur that include coupling with the sulfur cycle and reactions with

  14. Liming and Fertilization Effects on Triticale (XTriticosecale W.) Yield Between 1999 and 2006

    Science.gov (United States)

    László Phd, M., ,, Dr.

    2009-04-01

    .6452***, NK: R = 0.6998***, NPK: R = 0.5555***, NPKCa: R = 0.5578***, NPKMg: R = 0.4869**, NPKCaMg: R = 0.4341**). However, the total regression coefficients ranged from 0.43 to 0.74 in depence on the different nutrient application. Maximum yields of 5.8-6.0 t . ha-1 were achieved in the rainfall range of 580-620 mm. At values above and below this domain of the precipitation the grain yield reduced quadratically. So, it can be stated that both, drought and excess rainfall conditions resulted dramatically in significant negative effects between fertilization (N, P, K, Ca, Mg) and triticale yield. Keywords: precipitation, fertilization, liming, triticale, yield Introduction: The hazards associated with climate change are depend on the interaction of several systems with many variables (Johnston, 2000). Accummulation of carbon dioxide, methane, water vapor, ozone, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons (build-up of greenhouse gases) in the atmosphere and trends in their emissions suggest that we can expect significant environmental changes in the 21th century (Cynthia and Ana, 2006; Eric 2006). However, a recent consensus has emerged that between the greenhouse gases rising of atmospheric concentrations of carbon dioxide could become the more dangerous bacause it causing the global warming (Láng, 2005). Today, most researchers believe that higher temperature, drought and rainfall excess caused by climate change will depress crop yields in many places in the coming decades (Kádár et al., 2000; Jolánkai, 2005). Thus, in the last decades many agricultural investigations focused on understanding the relation between mean climate change and crop production (Runge, 1968; Várallyay, 1992). Changes in weather patterns were observed thoughout Europe including Hungary as early as 1850. Among the natural consequences of changing weather patterns, years of drought (rainfall deficit) and wet (rainfall excess) conditions, resulted in

  15. Thermoelectric Devices: Solid-State Refrigerators and Electrical Generators in the Classroom

    Science.gov (United States)

    Winder, Edmund J.; Ellis, Arthur B.; Lisensky, George C.

    1996-10-01

    Thermoelectric devices are solid-state devices that convert thermal energy from a temperature gradient into electrical energy (the Seebeck effect) or convert electrical energy into a temperature gradient (the Peltier effect). The first application is used most notably in spacecraft power generation systems (for example, in Voyager I and II) and in thermocouples for temperature measurement, while the second application is largely used in specialized cooling applications. Both applications can be demonstrated in the lecture hall to illustrate thermodynamic principles in a compelling manner. They also provide insight into the workings of a high-tech system that is achieving more widespread consumer use. The most visible consumer use of thermoelectric devices utilizing the Peltier effect is in portable electric food coolers/warmers that plug into an automobile cigarette lighter. Conventional cooling systems such as those used in refrigerators utilize a compressor and a working fluid to transfer heat. Thermal energy is absorbed and released as the working fluid undergoes expansion and compression and changes phase from liquid to vapor and back, respectively (1). Semiconductor thermoelectric coolers (also known as Peltier coolers) offer several advantages over conventional systems. They are entirely solid-state devices, with no moving parts; this makes them rugged, reliable, and quiet. They use no ozone-depleting chlorofluorocarbons, potentially offering a more environmentally responsible alternative to conventional refrigeration. They can be extremely compact, much more so than compressor-based systems. Precise temperature control (gun for about a minute started the motor again and allowed it to run for eight minutes. The motor can also be powered by heating the heat sink without first immersing the other side in ice water. Once the motor has started running, it can be made to run in the opposite direction by heating the other heat sink and establishing a temperature