Sample records for previous ozone o3

  1. Transformation of dissolved organic matter in concentrated leachate from nanofiltration during ozone-based oxidation processes (O3, O3/H2O2 and O3/UV).

    Wang, Hua-Wei; Li, Xiao-Yue; Hao, Zhi-Peng; Sun, Ying-Jie; Wang, Ya-Nan; Li, Wei-Hua; Tsang, Yiu Fai


    In this study, the transformation of dissolved organic matter (DOM) in nanofiltration concentrated leachate during three ozone-based oxidation processes (i.e., O3, O3/H2O2 and O3/UV) was investigated. The transformation characteristics of DOM were evaluated by gel filtration chromatography (GFC), XAD-8 resin fractionation, excitation-emission matrix fluorescence spectroscopy (EEM) and Fourier transform infrared spectroscopy (FTIR). Compared with O3-alone process, the removal efficiencies of COD, TOC, and color were improved in O3-combined processes (i.e., O3/H2O2 and O3/UV) approximately by 10-15%, 7-15%, and 15-20%, respectively. Humic acid (HA) was completely degraded and preferentially reacted with the oxidants during ozonation processes. HA was first converted into fulvic acid (FA), and then the majority of these intermediates were further converted to hydrophilic fraction (HyI). The GFC results indicated that the broader molecular weight distribution of DOM was observed, and high molecular weight DOM (i.e., 0.45 μm-100 kDa) was successfully converted to low molecular weight organics in the range of 1-10 kDa after ozonation reactions. The EEM spectra also showed that HA and FA were effectively converted into HyI after ozonation for 90 min. It is suggested that ozone-based oxidation processes could effectively change the DOM distribution and fluorescence features of concentrated leachate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. What Is Eating Ozone? Thermal Reactions between SO2 and O3: Implications for Icy Environments

    Loeffler, Mark J.; Hudson, Reggie L.


    Laboratory studies are presented, showing for the first time that thermally driven reactions in solid H2O + SO2 + O3 mixtures can occur below 150 K, with the main sulfur-containing product being bisulfate ({{{HSO}}4}-). Using a technique not previously applied to the low-temperature kinetics of either interstellar or solar-system ice analogs, we estimate an activation energy of 32 kJ mol-1 for {{{HSO}}4}- formation. These results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making detection of these molecules in the same vicinity unlikely. Our results also explain why O3 has not been detected on Callisto and why the SO2 concentration on Callisto appears to be highest on that world’s leading hemisphere. Furthermore, our results predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. Our work suggests that thermal reactions in ices play a much more important role in surface and sub-surface chemistry than generally appreciated, possibly explaining the low abundance of sulfur-containing molecules and the lack of ozone observed in comets and interstellar ices.

  3. Degradation of linuron by UV, ozonation, and UV/O(3) processes--effect of anions and reaction mechanism.

    Rao, Y F; Chu, W


    A comprehensive study of the degradation of linuron, one of the phenylurea herbicides, was conducted by using different treatment processes including UV, ozonation and UV/O(3). The effect of various anions on the performance of ozonation has been examined. N-terminus demethoxylation, photohydrolysis with or without dechlorination, and N-terminus demethylation have been found to be the major mechanisms in the linuron decay under the irradiation of UV at 254 nm while N-terminus demethoxylation, dechlorination and hydroxylation on benzene ring was observed to be involved in the ozonation process. Eight new intermediates were identified in UV process in this study compared with previous studies. Different decay pathways were proposed based on the identified intermediates in the three studied processes. UV/O(3) has demonstrated the best performance among these three processes in terms of LNR decay, mineralization, dechlorination and de-nitrogenation.

  4. Validation of MIPAS IMK/IAA V5R_O3_224 ozone profiles

    A. Laeng


    Full Text Available We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofísica de Andalucía MIPAS (Michelson Interferometer for Passive Atmospheric Sounding research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005–April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R_O3_220 (Laeng et al., 2014, is found: the known high bias around the ozone vmr (volume mixing ratio peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV.

  5. Ozone (O3: an excellent adjunctive tool in medical and surgical management of patient

    Vipin Thakkar


    Full Text Available In the condition like increasing susceptibility to allergic reaction and weaken response to antibiotics, along with constantly growing prices for medical treatment, new non-medicinal methods are to be appreciated. The history of medical ozone starts in the XX century. The pioneers to apply ozone in clinical practice were E. Payer, A. Fish and H. Wolf. Ozone as an antiseptic means had been known and used from the beginning of the XX century, however, extensive and systemic research in the field of ozone therapy started in Germany in mid 70s, when ozone-resistant polymer materials and convenient ozone generating equipment came into every day clinical practice. Ozone (O3 therapy due to its disinfection effect and its capacity to transport and release oxygen into tissues is gaining a justified recognizing in many countries of the world. O3 therapy can produce its immune modulators, anti-inflammatory, bactericidal, virucidal, fungicidal, analgesics and other effects. Considering this the purpose of this literature is to highlight the significance of Ozone as an excellent adjunctive tool in the management of various medical and surgical conditions. [Int J Res Med Sci 2014; 2(4.000: 1257-1261

  6. Human Ozone (O3) Exposure Alters Serum Profile of Lipid Metabolites

    HUMAN OZONE (O3) EXPOSURE ALTERS SERUM PROFILE OF LIPID METABOLITES Miller, D B.1; Kodavanti, U P.2 Karoly, E D.3; Cascio W.E2, Ghio, A J. 21. UNC-Chapel Hill, Chapel Hill, N.C., United States. 2. NHEERL, U.S. EPA, RTP, N.C., United States. 3. METABOLON INC., Durham, N.C., United...

  7. Human Ozone (O3) Exposure Alters Serum Profile of Lipid Metabolites

    HUMAN OZONE (O3) EXPOSURE ALTERS SERUM PROFILE OF LIPID METABOLITES Miller, D B.1; Kodavanti, U P.2 Karoly, E D.3; Cascio W.E2, Ghio, A J. 21. UNC-Chapel Hill, Chapel Hill, N.C., United States. 2. NHEERL, U.S. EPA, RTP, N.C., United States. 3. METABOLON INC., Durham, N.C., United...

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

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


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

  9. Catalytic activity of cerium-doped Ru/Al2O3 during ozonation of dimethyl phthalate

    Yunrui ZHOU; Wanpeng ZHU; Xun CHEN


    In this paper, factors influencing the mineraliza-tion of dimethyl phthalate (DMP) during catalytic ozona-tion with a cerium-doped Ru/Al2O3 catalyst were studied. The catalytic contribution was calculated through the results of a companrison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 rain reached 75.1%, 61.3% using Ru/Al2O3 catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium'were simultaneously loaded onto Al2O3 support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion's and heterogeneous catalytic ozonation confirmed that the contribution of het-erogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru-Ce/Al2O3 on catalytic activity.

  10. Sex differences in diet and inhaled ozone (O3) induced metabolic impairment

    APS 2015 abstract Sex differences in diet and inhaled ozone (O3) induced metabolic impairment U.P. Kodavanti1, V.L. Bass2, M.C. Schladweiler1, C.J. Gordon3, K.A. Jarema1, P. Phillips1, A.D. Ledbetter1, D.B. Miller4, S. Snow5, J.E. Richards1. 1 EPHD, NHEERL, USEPA, Research Triang...

  11. Sex differences in diet and inhaled ozone (O3) induced metabolic impairment

    APS 2015 abstract Sex differences in diet and inhaled ozone (O3) induced metabolic impairment U.P. Kodavanti1, V.L. Bass2, M.C. Schladweiler1, C.J. Gordon3, K.A. Jarema1, P. Phillips1, A.D. Ledbetter1, D.B. Miller4, S. Snow5, J.E. Richards1. 1 EPHD, NHEERL, USEPA, Research Triang...

  12. The 1988 Antarctic ozone depletion - Comparison with previous year depletions

    Schoeberl, Mark R.; Stolarski, Richard S.; Krueger, Arlin J.


    The 1988 spring Antarctic ozone depletion was observed by TOMS to be substantially smaller than in recent years. The minimum polar total ozone values declined only 15 percent during September 1988, compared to nearly 50 percent during September 1987. At southern midlatitudes, exceptionally high total ozone values were recorded beginning in July 1988. The total integrated southern hemispheric ozone increased rapidly during the Austral spring, approaching 1980 levels during October. The high midlatitude total ozone values were associated with a substantial increase in eddy activity as indicated by the standard deviation in total ozone in the zonal band 30-60 deg S. Mechanisms through which the increased midlatitude eddy activity could disrupt the formation of the Antarctic ozone hole are briefly discussed.

  13. Ethylenediurea (EDU) affects the growth of ozone-sensitive and tolerant ash (Fraxinus excelsior) trees under ambient O3 conditions.

    Paoletti, Elena; Contran, Nicla; Manning, William J; Tagliaferro, Francesco


    Adult ash trees (Fraxinus excelsior L.), known to be sensitive or tolerant to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion over the 2005 growing season (32.5 ppm h AOT40). Tree and shoot growth were recorded in May and September. Leaf area, ectomycorrhizal infection, and leaf and fine root biomass were determined in September. EDU enhanced shoot length and diameter, and the number and area of leaves, in both O3-sensitive and tolerant trees. However, no EDU effects were recorded at the fine root and tree level. Therefore, a potential for EDU protection against O3-caused growth losses of forest trees should be evaluated during longer-term experiments.

  14. Inhaled ozone (O3)-induces changes in serum metabolomic and liver transcriptomic profiles in rats☆

    Miller, Desinia B.; Karoly, Edward D.; Jones, Jan C.; Ward, William O.; Vallanat, Beena D.; Andrews, Debora L.; Schladweiler, Mette C.; Snow, Samantha J.; Bass, Virginia L.; Richards, Judy E.; Ghio, Andrew J.; Cascio, Wayne E.; Ledbetter, Allen D.; Kodavanti, Urmila P.


    Air pollution has been linked to increased incidence of diabetes. Recently, we showed that ozone (O3) induces glucose intolerance, and increases serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that O3 exposure will cause systemic changes in metabolic homeostasis and that serum metabolomic and liver transcriptomic profiling will provide mechanistic insights. In the first experiment, male Wistar Kyoto (WKY) rats were exposed to filtered air (FA) or O3 at 0.25, 0.50, or 1.0 ppm, 6 h/day for two days to establish concentration-related effects on glucose tolerance and lung injury. In a second experiment, rats were exposed to FA or 1.0 ppm O3, 6 h/day for either one or two consecutive days, and systemic metabolic responses were determined immediately after or 18 h post-exposure. O3 increased serum glucose and leptin on day 1. Glucose intolerance persisted through two days of exposure but reversed 18 h-post second exposure. O3 increased circulating metabolites of glycolysis, long-chain free fatty acids, branched-chain amino acids and cholesterol, while 1,5-anhydroglucitol, bile acids and metabolites of TCA cycle were decreased, indicating impaired glycemic control, proteolysis and lipolysis. Liver gene expression increased for markers of glycolysis, TCA cycle and gluconeogenesis, and decreased for markers of steroid and fat biosynthesis. Genes involved in apoptosis and mitochondrial function were also impacted by O3. In conclusion, short-term O3 exposure induces global metabolic derangement involving glucose, lipid, and amino acid metabolism, typical of a stress–response. It remains to be examined if these alterations contribute to insulin resistance upon chronic exposure. PMID:25838073

  15. Inactivation of Bacillus cereus and Salmonella enterica serovar Typhimurium by aqueous ozone (O3): Modeling and Uv-Vis spectroscopic analysis

    Ozone (O3) is a natural antimicrobial agent with potential applications in food industry. In this study, inactivation of Bacillus cereus and Salmonella enterica Typhimurium by aqueous ozone was evaluated. Ozone gas was generated using a domestic ozone generator with an output of 200 mg/hr (approx. 0...

  16. In situ DRIFTS study of O3 adsorption on CaO, γ-Al2O3, CuO, α-Fe2O3 and ZnO at room temperature for the catalytic ozonation of cinnamaldehyde

    Wu, Jianfeng; Su, Tongming; Jiang, Yuexiu; Xie, Xinling; Qin, Zuzeng; Ji, Hongbing


    In situ DRIFTS were conducted to identify adsorbed ozone and/or adsorbed oxygen species on CaO, ZnO, γ-Al2O3, CuO and α-Fe2O3 surfaces at room temperature. Samples were characterized by means of TG, XRD, N2 adsorption-desorption, pyridine-IR, nitrobenzene-IR, chloroform-IR, and CO2-TPD. Pyridine-DRIFTS measurements evidence two kinds of acid sites in all the samples. Nitrobenzene, chloroform-DRIFTS, and CO2-TPD reveal that there are large amounts of medium-strength base sites on all the metal oxides, and only CaO, ZnO, and γ-Al2O3 have strong base sites. And the benzaldehyde selectivity was increased in the same order of the alkalinity of the metal oxides. With weaker sites, ozone molecules form coordinative complexes bound via the terminal oxygen atom, observed by vibrational frequencies at 2095-2122 and 1026-1054 cm-1. The formation of ozonide O3- at 790 cm-1, atomic oxygen at 1317 cm-1, and superoxide O2- at 1124 cm-1 was detected; these species are believed to be intermediates of O3 decomposition on strong acid/base sites. The adsorption of ozone on metal oxides is a weak adsorption, and other gases, such as CO2, will compete with O3 adsorption. The mechanism of cinnamaldehyde ozonation at room temperature over CaO shows that cinnamaldehyde can not only be oxidized into cinnamic acid, but also be further oxidized into benzaldehyde, benzoic acid, maleic anhydride, and ultimately mineralized to CO2 in the presence of O3.

  17. Predicting and partitioning ozone fluxes to maize crops from sowing to harvest: the Surfatm-O3 model

    N. Mascher


    Full Text Available Terrestrial ecosystems represent a major sink for ozone (O3 and also a critical control of tropospheric O3 budget. However, due to its deleterious effects, plant functioning is affected by the ozone absorbed. It is thus necessary to both predict total ozone deposition to ecosystems and partition the fluxes in stomatal and non-stomatal pathways. The Surfatm-O3 model was developed to predict ozone deposition to agroecosystems from sowing to harvest, taking into account each deposition pathways during bare soil, growth, maturity, and senescence periods. An additional sink was added during senescence: stomatal deposition for yellow leaves, not able to photosynthesise but transpiring. The model was confronted to measurements performed over three maize crops in different regions of France. Modelled and measured fluxes agreed well for one dataset for any phenological stage, with only 3 % difference over the whole cropping season. A larger discrepancy was found for the two other sites, 16 % and 19 % over the entire study period, especially during bare soil, early growth and senescence. This was attributed to site-specific soil resistance to ozone and possible chemical reactions between ozone and volatile organic compounds emitted during late senescence. Considering both night-time and daytime conditions, non-stomatal deposition was the major ozone sink, from 100 % during bare soil period to 70–80 % on average during maturity. However, considering only daytime conditions, especially under optimal climatic conditions for plant functioning, stomatal flux could represent 75 % of total ozone flux. This model could improve estimates of crop yield losses and projections of tropospheric ozone budget.

  18. Ozone stomatal flux and O3 concentration-based metrics for Astronium graveolens Jacq., a Brazilian native forest tree species.

    Cassimiro, Jéssica C; Moura, Bárbara B; Alonso, Rocio; Meirelles, Sérgio T; Moraes, Regina M


    The current levels of surface ozone (O3) are high enough to negatively affect trees in large regions of São Paulo State, southeastern Brazil, where standards for the protection of vegetation against the adverse effects of O3 do not exist. We evaluated three O3 metrics - phytotoxic ozone dose (POD), accumulated ozone exposure over the threshold of 40 ppb h (AOT40), and the sum of all hourly average concentrations (SUM00) - for the Brazilian native tropical tree species Astronium graveolens Jacq. We used the DO3SE (Deposition of Ozone for Stomatal Exchange) model and calculated PODY for different thresholds (from 0 to 6 mmol O3 m(-2) PLA s(-1)), evaluating the model's performance through the relationship between measured and modelled conductance. The response parameters were: visible foliar injury, considered as incidence (% injured plants), severity (% injured leaves in relation to the number of leaves on injured plants), and leaf abscission. The model performance was suitable and significant (R(2) = 0.58; p < 0.001). POD0 was better correlated to incidence and leaf abscission, and SUM00 was better correlated to severity. The highest values of O3 concentration-based metrics (AOT40 and SUM00) did not coincide with those of POD0. Further investigation may improve the model and contribute to the proposition of a national standard for the protection of native species.

  19. 高湿度条件下O3在MnOx/γ-Al2O3催化剂上的分解%DECOMPOSITION OF OZONE OVER MnOx/γ-Al2O3 CATALYSTS

    杨庆良; 谢家理; 许正; 张婉琳; 冯易君


    Thecatalysts MnOx/γ-Al2O3 were prepared by means of co-precipitation method and their catalytic performance for the decomposition of ozone was investigated. The results show that at a caculation temperation of 500℃ and in a 1:3 molecule ratio of Mn and Al, the ozone decomposition ratio was very high even under high humidity condition. Atthe same time the catalysts before and after the reaction were examined by XRD, IR and XPS techniques. The decomposition of ozone results in the change of the active site on the catalyst and the appearance of a new oxygen species. Furthermore the mechanism of those O3 decomposition processes was discussed.%用共沉淀法制备了一系列MnOx/γ-Al2O3催化剂,并考察了它们对O3分解的催化性能.结果表明,Mn/Al摩尔比为1:3,煅烧温度为500℃时制得的催化剂即使在高湿度条件下,对O3也有很好的催化分解效果.XRD,IR,XPS等分析表明,催化剂的活性中心锰在反应前后其形态发生改变,催化剂表面有新的氧物种出现.进一步依据催化剂表面羟基对O3分解的影响,解释了O3在高湿度条件下的催化分解过程.

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

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

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

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


    Acute exacerbations of asthma represent a common clinical problem with major economic impact. Air pollutants including ozone have been shown to contribute to asthma exacerbation, but the mechanisms underlying ozone-induced asthma exacerbation are only partially understood. The present study aimed...... exposure to clean air or 100, 250, or 500 ppb ozone. Ozone induced AHR in mice previously exposed to OVA when compared to non-exposed (saline) control mice. After a 10-d exposure to OVA, a single exposure to a low (100 ppb) ozone concentration was sufficient to induce AHR. The AHR response was associated...... with goblet-cell metaplasia. Even the lowest concentration of ozone tested, 100 ppb, which may be exceeded in urban environments and in the workplace, resulted in a significant increase in AHR, most prominent 24 h after exposure in the OVA-exposed mice....

  2. A new approach to ozone plant fumigation: The Web-O3-Fumigation. Isoprene response to a gradient of ozone stress in leaves of Quercus pubescens

    Tricoli D


    Full Text Available The innovative Web-O3-Fumigation (WOF is a suitable technique to study O3 effects in plants. Through WOF, a very high dose of O3 fumigation may be obtained at the level of selected leaves, while allowing a gradient of ozone stress in branches at different distance from branch directly fumigated with O3 diffusing from perforated Teflon tubes. We used WOF to study the impact of O3 on the emission of isoprene, a putatively powerful antioxidant, in leaves of Quercus pubescens. In our experiment we produced with WOF: i approximately 300 ppb O3 on the leaves of the branch directly exposed to the pollutant; ii approximately 190 ppb on the leaves of the branches distant less than 30 cm from the treated branch; iii a summer ambient O3 concentration (100 ppb on the leaves of the branches distant more than 30 cm from the branch directly fumigated. High O3 concentrations induced a long-lasting inhibition of photosynthesis and isoprene emission in leaves which were directly fumigated. However, isoprene emission was stimulated by intermediate O3 concentration 288 hours after the end of the treatment. Isoprene stimulation, and the activation of the related antioxidant mechanism, may therefore be dependent on the O3 concentration and may be different in plant canopies depending on their exposure to the pollutant

  3. A new approach to ozone plant fumigation: The Web-O3-Fumigation. Isoprene response to a gradient of ozone stress in leaves of Quercus pubescens.

    Pinelli P


    Full Text Available The innovative Web-O3-Fumigation (WOF is a suitable technique to study O3 effects in plants. Through WOF, a very high dose of O3 fumigation may be obtained at the level of selected leaves, while allowing a gradient of ozone stress in branches at different distance from branch directly fumigated with O3 diffusing from perforated Teflon tubes. We used WOF to study the impact of O3 on the emission of isoprene, a putatively powerful antioxidant, in leaves of Quercus pubescens. In our experiment we produced with WOF: i approximately 300 ppb O3 on the leaves of the branch directly exposed to the pollutant; ii approximately 190 ppb on the leaves of the branches distant less than 30 cm from the treated branch; iii a summer ambient O3 concentration (100 ppb on the leaves of the branches distant more than 30 cm from the branch directly fumigated. High O3 concentrations induced a long-lasting inhibition of photosynthesis and isoprene emission in leaves which were directly fumigated. However, isoprene emission was stimulated by intermediate O3 concentration 288 hours after the end of the treatment. Isoprene stimulation, and the activation of the related antioxidant mechanism, may therefore be dependent on the O3 concentration and may be different in plant canopies depending on their exposure to the pollutant

  4. UV-Enhanced Room Temperature Ozone Sensor Based on Hierarchical SnO2-In2O3

    SUN Jian-bo; XU Jing; WANG Biao; SUN Peng; LIU Feng-min; LU Ge-yu


    SnO2-In2O3 hierarchical microspheres were prepared by the hydrothcrmal and solvothermal method.The morphology,phase crystallinity of the obtained SnO2-In2O3 were measured by X-ray diffraction(XRD),scan electron microscopy(SEM),respectively.A room temperature ozone sensor based on SnO2-In2O3 hierarchical microsphcres was fabricated and investigated.The gas sensing properties of the sensor using SnO2-In2O3 strongly depended on the proportion of SnO2 and In2O3.The sensitivity and response/recovery speed were greatly enhanced by UV illumination.A gas sensing mechanism related to oxygen defect was suggested.


    Ozone production efficiency (OPE) can be defined as the number of ozone (O3) molecules photochemically produced by a molecule of NOx (NO + NO2) before it is lost from the NOx - O3 cycle. Here, we consider observational and modeling techniques to evaluate various operational defi...

  6. [Responses of rice growth and development to elevated near-surface layer ozone (O3) concentration: a review].

    Yang, Lian-xin; Wang, Yu-long; Shi, Guang-yao; Wang, Yun-xia; Zhu, Jian-guo


    Ozone (O3) is recognized as one of the most important air pollutants. At present, the worldwide average tropospheric O3 concentration has been increased from an estimated pre-industrial level of 38 nl L(-1) (25-45 nl L(-1), 8-h summer seasonal average) to approximately 50 nl L(-1) in 2000, and to 80 nl L(-1) by 2100 based on most pessimistic projections. Oryza sativa L. (rice) is the most important grain crop in the world, and thus, to correctly evaluate how the elevated near-surface layer O3 concentration will affect the growth and development of rice is of great significance. This paper reviewed the chamber (including closed and open top chamber)-based studies about the effects of atmospheric ozone enrichment on the rice visible injury symptoms, photosynthesis, water relationship, phenology, dry matter production and allocation, leaf membrane protective system, and grain yield and its components. Further research directions in this field were discussed.

  7. Equivalent oxide thickness scaling of Al2O3/Ge metal-oxide-semiconductor capacitors with ozone post oxidation

    Sun Jia-Bao; Yang Zhou-Wei; Geng Yang; Lu Hong-Liang; Wu Wang-Ran; Ye Xiang-Dong; David Zhang Wei


    Aluminum-oxide films deposited as gate dielectrics on germanium (Ge) by atomic layer deposition were post oxidized in an ozone atmosphere.No additional interracial layer was detected by the high-resolution cross-sectional transmission electron microscopy and X-ray photoelectron spectroscopy measurements made after the ozone post oxidation (OPO) treatment.Decreases in the equivalent oxide thickness of the OPO-treated Al2O3/Ge MOS capacitors were confirmed.Furthermore,a continuous decrease in the gate leakage current was achieved with increasing OPO treatment time.The results can be attributed to the film quality having been improved by the OPO treatment.

  8. [Effects of O3-FACE(ozone-free air control enrichment) on gas exchange and chlorophyll fluorescence of rice leaf].

    Liang, Jing; Zeng, Qing; Zhu, Jian-Guo; Zhu, Chun-Wu; Cao, Ji-Ling; Xie, Zu-Bin; Liu, Gang; Tang, Hao-Ye


    O3-FACE (Ozone-free air control enrichment) platform has been established for observing the effect of elevated tropospheric ozone concentration on the gas exchange and chlorophyll fluorescence of two rice varieties (Wuyunjing 21 and Liangyoupeijiu). The results showed that high ozone concentration decreased the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of rice leaves. After 76d fumigation the decline in them for Wuyunjing 21 was as follows: 21.7%, 26.64% and 24.74% respectively, and that for Liangyoupeijiu was as follows: 25.53%, 30.31% and 25.48% respectively; however, no significant impact on leaf intercellular CO2 concentration was observed. Chlorophyll fluorescence kinetics parameters changed as can be seen by the decrease in F0 (initial fluorescence in the dark), ETR (The apparent electron transfer rate) and psiPSII (actual photochemical efficiency of PS II in the light), and the increase in NPQ (non-photochemical quenching). After 76 days of O3 treatment, the NPQ of Wuyunjing 21 and Liangyoupeijiu was enhanced by 16.37% and 11.77%, respectively. The impact of ozone on rice was a cumulative effect, and the extent of variation in the above parameters and the differences between the two varieties were enlarged as the O3 treatment time increased; At the same time because the rice leaf intercellular CO2 concentration did not significantly reduce, the inferred decrease in net photosynthetic rate was restricted by non-stomatal factors. The results of this experiment indicated that Liangyoupeijiu was more susceptible to ozone than Wuyunjing 21.

  9. High Ozone (O3) Affects the Fitness Associated with the Microbial Composition and Abundance of Q Biotype Bemisia tabaci

    Hong, Yanyun; Yi, Tuyong; Tan, Xiaoling; Zhao, Zihua; Ge, Feng


    Ozone (O3) affects the fitness of an insect, such as its development, reproduction and protection against fungal pathogens, but the mechanism by which it does so remains unclear. Here, we compared the fitness (i.e., the growth and development time, reproduction and protection against Beauveria bassiana (B. bassiana) of Q biotype whiteflies fumigated under hO3 (280 ± 20 ppb) and control O3 (50 ± 10 ppb) concentrations. Moreover, we determined that gene expression was related to development, reproduction and immunity to B. bassiana and examined the abundance and composition of bacteria and fungi inside of the body and on the surface of the Q biotype whitefly. We observed a significantly enhanced number of eggs that were laid by a female, shortened developmental time, prolonged adult lifespan, decreased weight of one eclosion, and reduced immunity to B. bassiana in whiteflies under hO3, but hO3 did not significantly affect the expression of genes related to development, reproduction and immunity. However, hO3 obviously changed the composition of the bacterial communities inside of the body and on the surface of the whiteflies, significantly reducing Rickettsia and enhancing Candidatus_Cardinium. Similarly, hO3 significantly enhanced Thysanophora penicillioides from the Trichocomaceae family and reduced Dothideomycetes (at the class level) inside of the body. Furthermore, positive correlations were found between the abundance of Candidatus_Cardinium and the female whitefly ratio and the fecundity of a single female, and positive correlations were found between the abundance of Rickettsia and the weight of adult whiteflies just after eclosion and immunity to B. bassiana. We conclude that hO3 enhances whitefly development and reproduction but impairs immunity to B. bassiana, and our results also suggest that the changes to the microbial environments inside of the body and on the surface could be crucial factors that alter whitefly fitness under hO3. PMID:27799921

  10. Spatial and temporal variability of tropospheric ozone (O3) in the boundary layer above the Aegean Sea (eastern Mediterranean)

    Kouvarakis, G.; Vrekoussis, M.; Mihalopoulos, N.; Kourtidis, K.; Rappenglueck, B.; Gerasopoulos, E.; Zerefos, C.


    To study the spatial and temporal variability of tropospheric ozone in the marine boundary layer over the Aegean Sea (eastern Mediterranean), an O3 analyzer has been installed onboard of a passenger vessel traveling on a regular basis in the Aegean Sea (from Heraklion/Crete 35°30'N, 25°13'E to Thessaloniki 40°64'N, 22°97'E) during a period of 14 months (August 1999 to November 2000). In addition, O3 data have been obtained on a daily basis at the regional background station of Finokalia (Crete; 35°30'N, 25°70'E) since September 1997, short-term measurements of O3 were performed over Crete during the PAUR II campaign (May 1999), and the first O3 data from a rural area (40°32'N, 23°50'E) close to Thessaloniki at the north of Greece have been collected from March 2000 to January 2001. This survey extensive points out the existence of a well-defined seasonal cycle in boundary layer O3 with maximum in summer both above the Aegean Sea and at Finokalia. However, the seasonal signal (defined as the summer/winter ratio) is not constant and varies as a function of air mass origin from 1.33 to 1.15 for the N-NE and SW-S sectors, respectively, in line with the geographical location of the O3 precursor sources. Our data show the absence of any significant longitudinal gradient over Crete at least during spring and autumn and the absence of significant latitudinal gradient between the north and south Aegean Sea during all seasons for air masses having similar origin. The above results indicate that long-range transport is the main factor accounting for the elevated O3 levels above the eastern Mediterranean Sea. Thus (1) O3 data from Finokalia, where the longest time series are available for the area, have regional significance and (2) over the entire Aegean basin, ozone values are above the 32 ppbv European Union (EU) phytotoxicity limit throughout the year and above the 53 ppbv EU health protection limit most of the time during the dry season of the year. The very

  11. Monitoring O3 and Aerosols with the NASA LaRC Mobile Ozone Lidar System

    Ganoe, Rene; Gronoff, Guillaume; Berkoff, Timothy; DeYoung, Russell; Carrion, William


    The NASA's Langley Mobile Ozone Lidar (LMOL) system routinely measures tropospheric ozone and aerosol profiles, and is part of the Tropospheric Lidar Network (TOLNet). Recent upgrades to the system include a new pump laser that has tripled the transmission output power extending measurements up to 8 km in altitude during the day. In addition, software and algorithm developments have improved data output quality and enabled a real-time ozone display capability. In 2016, a number of ozone features were captured by LMOL, including the dynamics of an early-season ozone exceedance that impacted the Hampton Roads region. In this presentation, we will review current LMOL capabilities, recent air quality events observed by the system, and show a comparison of aerosol retrieval through the UV channel and the green line channel.

  12. Monitoring O3 and Aerosols with the NASA LaRC Mobile Ozone Lidar System

    Gronoff, G.; Ganoe, R. E.; Berkoff, T.; De Young, R.; Carrion, W.


    The NASA's Langley Mobile Ozone Lidar (LMOL) system routinely measures tropospheric ozone and aerosol profiles, and is part of the Tropospheric Lidar Network (TOLNet). Recent upgrades to the system include a new pump laser that has tripled the transmission output power extending measurements up to 8 km in altitude. In addition, software and algorithm developments have improved data output quality and enabled a real-time ozone display capability. In 2016, a number of ozone features were captured by LMOL, including the dynamics of an early-season ozone exceedance that impacted the Hampton Roads region. In this presentation, we will review current LMOL capabilities, recent air quality events observed by the system, and we show a comparison of aerosol retrieval through the UV channel and the green line channel.

  13. Ozone (1-Hr, O3) NAAQS Designations, Region 9, 2013, US EPA Region 9

    U.S. Environmental Protection Agency — Esri polygon shapefile of 1-hour ozone designated areas in US EPA Region 9. Nonattainment areas are geographic areas which have not met National Ambient Air Quality...

  14. Pattern Recognition of High O3 Episodes in Forecasting Daily Maximum Ozone Levels

    Jeong-Sook Heo


    Full Text Available In this study, a method was developed to diagnose ozone episodes exceeding environmental criteria (e.g., above 80 ppb on the basis of a multivariate statistical method and a fuzzy expert system. This method, being capable of characterizing the occurrence patterns of high-level ozone, was employed to forecast daily maximum ozone levels. The hourly data for both air pollutants and meteorological parameters, obtained both at the surface and at high elevation (500 hPa stations of Seoul City (1989-1996, were analyzed using this method. Through an application of the fuzzy expert system, the data sets were classified into 8 different types for common ozone episodes. In addition, the data sets were divided into patterns of 11 (Station A, 20 (Station B, 8 (Station C, and 10 (Station D for site-specific ozone episodes. The results of the analysis were successful in demonstrating that the method was sufficiently efficient to classify each class quantitatively with its own patterns of ozone pollution.

  15. Ozone (O3): A Potential Contributor to Metabolic Syndrome through Altered Insulin Signaling

    Air pollutants have been associated with diabetes and metabolic syndrome, but the mechanisms remain to be elucidated. We hypothesized that acute O3 exposure will produce metabolic impairments through endoplasmic reticular stress (ER) stress and altered insulin signaling in liver,...

  16. Comparison of Efficiencies and Mechanisms of Catalytic Ozonation of Recalcitrant Petroleum Refinery Wastewater by Ce, Mg, and Ce-Mg Oxides Loaded Al2O3

    Chunmao Chen


    Full Text Available The use of catalytic ozonation processes (COPs for the advanced treatment of recalcitrant petroleum refinery wastewater (RPRW is rapidly expanding. In this study, magnesium (Mg, cerium (Ce, and Mg-Ce oxide-loaded alumina (Al2O3 were developed as cost efficient catalysts for ozonation treatment of RPRW, having performance metrics that meet new discharge standards. Interactions between the metal oxides and the Al2O3 support influence the catalytic properties, as well as the efficiency and mechanism. Mg-Ce/Al2O3 (Mg-Ce/Al2O3-COP reduced the chemical oxygen demand by 4.7%, 4.1%, 6.0%, and 17.5% relative to Mg/Al2O3-COP, Ce/Al2O3-COP, Al2O3-COP, and single ozonation, respectively. The loaded composite metal oxides significantly increased the hydroxyl radical-mediated oxidation. Surface hydroxyl groups (–OHs are the dominant catalytic active sites on Al2O3. These active surface –OHs along with the deposited metal oxides (Mg2+ and/or Ce4+ increased the catalytic activity. The Mg-Ce/Al2O3 catalyst can be economically produced, has high efficiency, and is stable under acidic and alkaline conditions.

  17. Estimating Damage Cost of Net Primary Production due to Climate Change and Ozone(O3) Effect

    Park, J. H.; Lee, D. K.; Park, C.; Sung, S.; Kim, H. G.; Mo, Y.; Kim, S.; Kil, S.


    Forests are absorbing and storing carbon dioxide (CO2) through photosynthesis. The forests are not only preventing global warming but also influencing temperature, precipitation and humidity (Costanza et al., 1997; de Groot et al., 2002). Also the forests are recognized as a carbon sink internationally (van Kooten, 2009). The Korean Government supports the economic activity such as carbon offset projects in accordance with 'ACT ON THE MANAGEMENT AND IMPROVEMENT OF CARBON SINK' Article27 (Korea Forest Service, 2013) and aims to make a policy which improves the CO2 capacity of forest for Paris Agreement discussed in UNFCCC COP21, December 2015 (Korea Forest Service, 2015). However, the social-economic activities make to increase aerosols as well as greenhouse gases significantly since the industrial revolution, as a result, the chemical composition of the atmosphere has changed significantly. According to the resent studies, not only CO2 but atmospheric chemistries such as ozone (O3), aerosol and black carbon can be an important factor causing climate change (Hansen et al., 2007; IPCC, 2007). In the past, acid rain affected on forest, but in these days, O3, nitrogen oxide (NOX) and sulfur oxide (SOX) are the most threatening factors on forest ecosystem (Lee et al, 2011). In particular, O3accounts for most of the photochemical products and causes a direct significant impact or damage on the plant because of high toxicity (Han et al., 2006). The research questions of this study are "How does O3 effects on forest productivity in the present and future? " What is the damage cost by the O3 effect in the future? In this study, we developed a statistical model using the parameters which effect on the forest productivity. We estimated the forest productivity using on the derived model in the present and future on a SSP scenarios. Lastly, we evaluated the economic effect or damage cost of O3effect by introducing the concept of climate insurance. The average forest

  18. Inhaled Ozone (O3)-Induces Changes in Serum Metabolomic and Liver Transcriptomic Profiles in Rats

    Air pollution has been linked to increased incidence of diabetes. Recently, we showed that ozone (03) induces glucose intolerance, and increases serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that 03 exposure will cause systemic changes in metab...

  19. Inhaled Ozone (O3)-Induces Changes in Serum Metabolomic and Liver Transcriptomic Profiles in Rats

    Air pollution has been linked to increased incidence of diabetes. Recently, we showed that ozone (03) induces glucose intolerance, and increases serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that 03 exposure will cause systemic changes in metab...

  20. Ozone: A Sourcebook for Teaching about O3 in the Troposphere and Stratosphere.

    Anderson, Norman D.

    This book and others in the Changes in the Environment Series were produced as part of the GLOBE-NET Project, a partnership of science teachers and research scientists working on various aspects of global change. This book contains up-to-date information about the ozone as well as ideas and resources for teaching about it. Sections of this…

  1. Effects of ozone (O3) therapy on cisplatin-induced ototoxicity in rats.

    Koçak, Hasan Emre; Taşkın, Ümit; Aydın, Salih; Oktay, Mehmet Faruk; Altınay, Serdar; Çelik, Duygu Sultan; Yücebaş, Kadir; Altaş, Bengül


    The aim of this study is to investigate the effect of rectal ozone and intratympanic ozone therapy on cisplatin-induced ototoxicity in rats. Eighteen female Wistar albino rats were included in our study. External auditory canal and tympanic membrane examinations were normal in all rats. The rats were randomly divided into three groups. Initially, all the rats were tested with distortion product otoacoustic emissions (DPOAE), and emissions were measured normally. All rats were injected with 5-mg/kg/day cisplatin for 3 days intraperitoneally. Ototoxicy had developed in all rats, as confirmed with DPOAE after 1 week. Rectal and intratympanic ozone therapy group was Group 1. No treatment was administered for the rats in Group 2 as the control group. The rats in Group 3 were treated with rectal ozone. All the rats were tested with DPOAE under general anesthesia, and all were sacrificed for pathological examination 1 week after ozone administration. Their cochleas were removed. The outer hair cell damage and stria vascularis damage were examined. In the statistical analysis conducted, a statistically significant difference between Group 1 and Group 2 was observed in all frequencies according to the DPOAE test. In addition, between Group 2 and Group 3, a statistically significant difference was observed in the DPOAE test. However, a statistically significant difference was not observed between Group 1 and Group 3 according to the DPOAE test. According to histopathological scoring, the outer hair cell damage score was statistically significantly high in Group 2 compared with Group 1. In addition, the outer hair cell damage score was also statistically significantly high in Group 2 compared with Group 3. Outer hair cell damage scores were low in Group 1 and Group 3, but there was no statistically significant difference between these groups. There was no statistically significant difference between the groups in terms of stria vascularis damage score examinations

  2. Treatment of a simulated phenolic effluent by heterogeneous catalytic ozonation using Pt/Al2O3.

    Fajardo, Ana S; Martins, Rui C; Quinta-Ferreira, Rosa M


    Non-catalytic and catalytic ozonation over Pt/Al2O3 were considered in the treatment of a synthetic effluent composed of six phenolic acids usually present in olive mill wastewaters. In both processes the medium pH affected the rate of ozone decomposition and the formation of hydroxyl radicals. The optimum values were achieved for the catalytic system under pH 7 with 93.0 and 47.7%, respectively, of total phenol content and chemical oxygen demand (COD) removal, after 120 minutes of reaction. For pH 3, the catalytic ozonation followed a free radical pathway perceived by the presence of radical scavengers. No significant structural differences were observed between the fresh and used solid catalyst in X-ray diffraction analysis. Aluminium leaching behaviour was also evaluated at the end of each experiment. Moreover, a sequence of feed-batch trials involving the catalyst reutilization exhibited almost constant activity during the operation time. Eco-toxicological tests were performed for both processes, revealing that the treated effluent still presents some ecological impact, although it is lower than that for the raw wastewater.

  3. Interface Properties of Atomic-Layer-Deposited Al2O3 Thin Films on Ultraviolet/Ozone-Treated Multilayer MoS2 Crystals.

    Park, Seonyoung; Kim, Seong Yeoul; Choi, Yura; Kim, Myungjun; Shin, Hyunjung; Kim, Jiyoung; Choi, Woong


    We report the interface properties of atomic-layer-deposited Al2O3 thin films on ultraviolet/ozone (UV/O3)-treated multilayer MoS2 crystals. The formation of S-O bonds on MoS2 after low-power UV/O3 treatment increased the surface energy, allowing the subsequent deposition of uniform Al2O3 thin films. The capacitance-voltage measurement of Au-Al2O3-MoS2 metal oxide semiconductor capacitors indicated n-type MoS2 with an electron density of ∼10(17) cm(-3) and a minimum interface trap density of ∼10(11) cm(-2) eV(-1). These results demonstrate the possibility of forming a high-quality Al2O3-MoS2 interface by proper UV/O3 treatment, providing important implications for their integration into field-effect transistors.

  4. Total column density variations of ozone (O3) in presence of different types of clouds

    G S Meena


    The zenith sky scattered light spectra were carried out using zenith sky UV-visible spectrometer in clear and cloudy sky conditions during May–November 2000 over the tropical station Pune (18°32′N, 73°51′E). These scattered spectra are obtained in the spectral range 462–498 nm between 75° and 92° solar zenith angles (SZAs). The slant column densities (SCDs) as well as total column densities (TCDs) of NO2, O3, H2O and O4 are derived with different SZAs in clear and cloudy sky conditions. The large enhancements and reductions in TCDs of the above gases are observed in thick cumulonimbus (Cb) clouds and thin high cirrus (Ci) clouds, respectively, compared to clear sky conditions. The enhancements in TCDs of O3 appear to be due to photon diffusion, multiple Mie-scattering and multiple reflections between layered clouds or isolated patches of optically thick clouds. The reductions in TCDs due to optically thin clouds are noticed during the above period. The variations in TCDs of O3 measured under cloudy sky are discussed with total cloud cover (octas) of different types of clouds such as low clouds (CL), medium clouds (CM) and high clouds (CH) during May–November 2000. The variations in TCDs of O3 measured in cloudy sky conditions are found to be well matched with cloud sensitive parameter colour index (CI) and found to be in good correlation. The TCDcloudy are derived using airmass factors (AMFs) computed without considering cloud cover and CI in radiative transfer (RT) model, whereas TCDmodel are derived using AMFs computed with considering cloud cover, cloud height and CI in RT model. The TCDmodel is the column density of illuminated cloudy effect. A good agreement is observed between TCDmodel, TCDDob and TCDGOME.

  5. 臭氧O3在食品微生物控制方面的应用%Ozone O3's application in the microbe control


    In recent years, ozone has been rapidly used in the foodstuff manufacturing industry, especially in the disinfection and sterilization for the workshop air, the effect is very remarkable; ozone's disinfection to the foodstuff's raw material, packaging container, pipeline, and equipment also gains the satisfied effect.

  6. Chemical production process of ozone in summer in Beijing urban area%北京城区夏季O_3化学生成过程

    徐敬; 马建中; 张小玲; 徐晓峰; 孟伟; 马志强; 赵秀娟


    选取2007年7月1日—8月31日中的21个晴空日,利用观测资料和光化学箱模式计算了北京城区测点的O3生成速率G(O3)和O3生成效率OPE.结果表明,21个晴空日中G(O3)日最高小时值分布在(18~82)×10-9h-1之间;在O3污染和非污染日G(O3)最高值的平均水平无显著差异,且与Ox浓度之间不存在一致的对应关系,表明O3化学生成过程不能全面解释地面O3浓度的累积,物理传输过程对测点O3实测浓度有显著作用;各个化学过程对G(O3)的贡献率对比结果显示,HO2在NO向NO2的转化中贡献最大;OPE值分布在2.8~5.8之间,总体水平为4.1±0.1;OPE值与NOx浓度之间为非线性关系,OPE值随NOx浓度的增加而减少,表明消减测点附近VOCs排放能有效降低O3浓度.%The gross ozone production rate G(Os ) and ozone production efficiency (OPE) is calculated with a photochemical box model constrained by observed data of 21 selected clear days obtained during July 1st to August 31th , 2004 in an urban area of Beijing. Results show that the daily maximum hourly -averaged G( O3 ) in these 21 selected clear days ranged from 18 ×10^-9 to 82 ×10^-9 h^-1. In average, the daily maximum G( O3 ) for ozone pollution days is not evidently different from that for ozone pollution-free days, and the G ( O3 ) is not in accord with the change of O3, either. This indicates that O3 photochemical production process could not explain the observed accumulation of O3 completely and physical transportation processes controlled the real O3 concentrations prominently. By comparing the contributions of individual chemical processes to the G( O3 ), it is shown that HO2 plays a dominant role in the conversion of NO to NO2. Ozone OPE ranged from 2.8 to 5.8, with art overall average of 4.1 ±0. 1 The relationship of OPE and NO, concentration is found to be non-linear and OPE decreases with increasing NOx , which indicates that reducing the

  7. Acute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II Diabetes

    Abstract for Society of Toxicology, March 22-25, 2015, San Diego, CAAcute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II DiabetesS.J. Snow1,3, D. Miller2, V. Bass2, M. Schladweiler3, A. Ledbetter3, J. Richards3, C...

  8. Acute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II Diabetes

    Abstract for Society of Toxicology, March 22-25, 2015, San Diego, CAAcute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II DiabetesS.J. Snow1,3, D. Miller2, V. Bass2, M. Schladweiler3, A. Ledbetter3, J. Richards3, C...

  9. Catalytic performance of Fe3O4-CoO/Al2O3 catalyst in ozonation of 2-(2,4-dichlorophenoxy) propionic acid,nitrobenzene and oxalic acid in water

    Shaoping Tong; Rui Shi; Hua Zhang; Chunan Ma


    the precursors,and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP),nitrobenzene and oxalic acid.The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant,and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism.The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance.In the catalytic ozonation of 2,4-DP,the apparent reaction rate constants (k) were determined to be 1.456×10-2 min-1 for ozonation alone and 4.740×10-2 min-1 for O3/Fe3O4-CoO/Al2O3.And O3/Fe3O4-CoO/Al2O3 had a larger Rct (6.614×10-9) calculated by the relative method than O3 did (1.800×10-9),showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical.Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid.The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.

  10. Cu/C-Al2O3催化臭氧氧化印染废水%Heterogeneous catalytic ozonation of dyeing wastewater by Cu/C-Al 2O3

    孟冠华; 刘宝河; 万彤; 孙曼; 张俊


    Catalyst Cu/C-Al2O3 has been prepared by impregnation-calcination method. The dyeing wastewater has been treated by catalytic ozonization process,using Cu/C-Al2O3 as catalyst and ozone as oxidant. The effects of fac-tors,such as dosage of catalyst,concentration of oxidant,pH,reaction time,etc. on treatment effectiveness are inves-tigated. The results show that when pH is 9,catalyst dosage 10 g/L,mass concentration of O3 55 mg/L and reaction time 60 min,the COD removing rate reaches 60%and removing rate of chroma reaches 96%.%采用浸渍-焙烧法制备了Cu/C-Al2O3。以Cu/C-Al2O3为催化剂,臭氧为氧化剂,对印染废水进行了催化臭氧化处理,考察了催化剂投加量、氧化剂浓度、pH和反应时间等因素对处理效果的影响。结果表明:当pH为9,催化剂投加量为10 g/L,O3质量浓度为55 mg/L,反应时间为60 min时, COD去除率达到60%,色度去除率达到96%。

  11. OMI/Aura Ozone (O3) Total Column 1-Orbit L2 Swath 13x24 km V003 NRT

    National Aeronautics and Space Administration — The OMI/Aura Level-2 Total Column Ozone Data Product OMTO3 Near Real Time data is made available from the OMI SIPS NASA for the public access. The Ozone Monitoring...

  12. Summertime weekly cycles of observed and modeled NOx and O3 concentrations as a function of land use type and ozone production sensitivity over the Continental United States

    P. Lee


    Full Text Available Simulation results from the Community Multiscale Air Quality (CMAQ model version 4.7.1 over the Conterminous United States (CONUS for August 2009 are analyzed to evaluate how satellite-derived O3 sensitivity regimes capture weekly cycles of the U.S. EPA's Air Quality System (AQS observed ground-level concentrations of ozone (O3. AQS stations are classified according to a geographically-based land use designation or an O3-NOx-VOC chemical sensitivity regime. Land use designations are derived from the Advanced Very High Resolution Radiometer (AVHRR global land cover characteristic data representing three features: urban regions, forest regions, and other regions. The O3 chemical regimes (NOx-saturated, mixed, and NOx-sensitive are inferred from low to high values of photochemical indicators based on the ratio of the HCHO to NO2 column density from the Global Ozone Monitoring Experiment 2 (GOME-2 and CMAQ. Both AQS-observed weekly cycles of NOx at measurement sites over AVHRR geographical regions and GOME-2 sensitivity regimes show high NOx on weekdays and low NOx on weekends. However, the AQS-observed O3 weekly cycle at sites over the GOME-2 NOx-saturated regime is noticeably different from that over the AVHRR urban region. Whereas the high weekend O3 anomaly is clearly shown at sites over the GOME-2 NOx-saturated regime in both AQS and CMAQ, the weekend effect is not captured at other sites over the AVHRR urban region. In addition, the weekend effect from AQS is more clearly discernible at sites above the GOME-2 NOx-saturated regime than at other sites above the CMAQ NOx-saturated regime. This study suggests that chemical classifications of GOME-2 chemical regime stations produces better results for weekly O3 cycles than either the CMAQ chemical or AVHRR geographical classifications.

  13. Study of tropospheric CO and O3 enhancement episode over Indonesia during Autumn 2006 using the Model for Ozone and Related chemical Tracers (MOZART-4)

    Srivastava, Shuchita; Sheel, Varun


    An intense biomass burning event occurred over Indonesia in Autumn of 2006. We study the impact of this event on the free tropospheric abundances of carbon monoxide (CO) and ozone (O3) using MOPITT (Measurements of Pollution In The Troposphere) observations, ozonesonde measurements and 3D chemistry transport model MOZART (Model for Ozone and Related chemical Tracers). MOPITT observations showed an episode of enhanced CO in the free troposphere over the Indonesian region during October-November 2006. This feature is reproduced well by MOZART. The model mass diagnostics identifies the source of enhanced CO mixing ratio in the free troposphere (100-250 ppbv) as due to convective processes. The implication of the fire plume on the vertical distribution of O3 over Kuala Lumpur has been studied. The tropospheric O3 increased over this location by 10-25 ppbv during Autumn 2006 as compared to Autumn 2005 and 2007. The MOZART model simulation significantly underestimated this tropospheric O3 enhancement. The model is run both with and without Indonesian biomass burning emissions to estimate the contribution of fire emission in CO and O3 enhancement. Biomass burning emission is found to be responsible for an average increase in CO by 104 ± 56 ppbv and O3 by 5 ± 1 ppbv from surface to 100 hPa range. The model results also showed that biomass burning and El Niño related dynamical changes both contributed (˜4 ppbv-12 ppbv) to the observed increase in tropospheric O3 over the Indonesian region during Autumn 2006.

  14. Investigation of wet-ozonation degradation for organic wastewater%有机废水湿式O3氧化降解过程的研究

    钟理; 詹怀宇


    The effect of different pH values,various temperatures and initial C2H3Cl concentrations on reaction process was studied experimen tally using ozone as a wet-oxidation process in degradating C2H3Cl wastewat e r.The mechanism for catalytic generation of hydroxyl radicals by ozone decomposi tion at high pH values,and the oxidative destruction of hazardous pollutants wer e explored primarily.The kinetic model of ozonation for C2H3Cl wastewater wa s obtained based on experimental investigation and analysis.%采用O3湿式氧化降解含氯乙烯的有机废水,实验研究了不 同pH、不同温度以及不同初始氯乙烯浓度对反应过程的影响,初步探讨了在高pH时O3的自 分解催化产生自由基OH*机理和污染物的氧化降解过程。通过实验研究与分析,获得了氯乙 烯有机废水O3氧化过程的动力学方程。

  15. Dynamics of ozone layer under Serbia and solar activity: Previous statement

    Ducić Vladan


    Full Text Available The aim of this paper is to identify ozone layer dynamics under Serbian area, as well as possible relations of change in stratospheric ozone concentration with some parameters of solar activity. During the period 1979-2005, the statistical decrease of ozone concentration was noticed under Serbian territory cumulatively for 24.5 DU (7.2%, apropos 9.4 DU (2.8% by decade. These changes are consistent with the changes in surrounding countries. From absolute minimum 1993, flexible trend of ozone layer pentad values validate hypotheses of its recovery. Correspondence of ozone thickness extreme period with Wolf's number and with the greatest volcanic eruptions shows that interannual variations of stratospheric ozone concentration are still in the function of natural factors above all, as are solar and volcanic activities. Investigation of larger number solar activity parameters shows statistically important antiphase synchronous between the number of polar faculae on the Sun and stratospheric ozone dynamics under Serbia. Respecting that relation between these two features until now isn't depicted, some possible causal mechanisms are proposed.

  16. Climate change: potential effects of increased atmospheric carbon dioxide (CO2), ozone (O3), and ultraviolet-B (UV-B) radiation on plant diseases.

    Manning, W J; V Tiedemann, A


    Continued world population growth results in increased emission of gases from agriculture, combustion of fossil fuels, and industrial processes. This causes changes in the chemical composition of the atmosphere. Evidence is emerging that increased solar ultraviolet-B (UV-B) radiation is reaching the earth's atmosphere, due to stratospheric ozone depletion. Carbon dioxide (CO(2)), ozone (O(3)) and UV-B are individual climate change factors that have direct biological effects on plants. Such effects may directly or indirectly affect the incidence and severity of plant diseases, caused by biotic agents. Carbon dioxide may increase plant canopy size and density, resulting in a greater biomass of high nutritional quality, combined with a much higher microclimate relative humidity. This would be likely to promote plant diseases such as rusts, powdery mildews, leaf spots and blights. Inoculum potential from greater overwintering crop debris would also be increased. Ozone is likely to have adverse effects on plant growth. Necrotrophic pathogens may colonize plants weakened by O(3) at an accelerated rate, while obligate biotroph infections may be lessened. Ozone is unlikely to have direct adverse effects on fungal pathogens. Ozone effects on plant diseases are host plant mediated. The principal effects of increased UV-B on plant diseases would be via alterations in host plants. Increased flavonoids could lead to increased diseased resistance. Reduced net photosynthesis and premature ripening and senescence could result in a decrease in diseases caused by biotrophs and an increase in those caused by necrotrophs. Microbial plant pathogens are less likely to be adversely affected by CO(2), O(3) and UV-B than are their corresponding host plants. Changes in host plants may result in expectable alterations of disease incidence, depending on host plant growth stages and type of pathogen. Given the importance of plant diseases in world food and fiber production, it is essential to

  17. A comparative rotational analysis of the 0 00 bands of the 3A 2← X˜1A 1 Wulf transition for the isotopomers 16O 3 and 18O 3 of ozone by high resolution Fourier transform spectrometry

    Bouvier, A. J.; Veyret, V.; Russier, I.; Inard, D.; Churassy, S.; Bacis, R.; Brion, J.; Malicet, J.; Judge, R. H.


    A high resolution Fourier transform spectrometry comparative analysis of the rotational structure of the 0 00 absorption band of the 3A 2← X˜1A 1 Wulf transition for the isotopomers 16O 3 and 18O 3 of the ozone molecule is presented. With a near pure case (b) coupling model for the upper triplet state, we identified, in these two rovibrational bands, numerous lines of sub-bands associated with the three F1( N= J-1), F2( N= J), F3( N= J+1) spin components. Many superpositions around the origin, plus perturbations and predissociation phenomena limit our unperturbed data set for the 3A 2 state to less than 100 unperturbed rotational lines in the range 9100-9550 cm -1 for each band. Using for each of them the well defined ground state parameters, we obtained a standard deviation of about 0.050 cm -1 in the fits to the lines. The rotational constants A, B, C, the three rotational distortion terms Δ K, Δ K, Δ J, the spin-rotation constants a0, a, and b and the spin-spin constant α are determined for the (0 0 0) vibrational level of the 3A 2 state and of the two isotopomers. The parameter β arbitrarily fixed for 16O 3 was successfully calculated for 18O 3 and this last result justifies the β value adopted for 16O 3. The geometrical parameters of the 3A 2 state for the two isotopomers are close, r=1.343 Å, θ=98.8° for 18O 3 and r=1.345 Å, and θ=98.9° for 16O 3. So are the Δ and κ values. The origin of the 18O 3 0 00 band is blue shifted by 20.6(4) cm -1 with respect to the 16O 3 0 00 band. For the congested parts of the spectra comparisons of both isotopic species has to be done in a special way through sub-band contours. We justify the existence of perturbations in the first vibrational levels of the 3A 2 state by several crossings with high vibrational levels of the ground state.

  18. Ozone Detection in the ppb Range with HSGFET Ozone Sensors Operating at Room Temperature%HSGFET型臭氧传感器室温下对纳诺量级O\\-3的检测

    牛文成; 吴小晔; 梅思滔; 谢建湘; 那兴波; 李华伟; 贾芸芳


    本文介绍了双敏感膜、复合悬浮栅(Hybrid Suspended Gate即HSG)FET型臭氧传感器的结构与制作.重点研究了敏感膜和结构不同的传感器对O\\-3敏感性的影响,并对所得实验结果进行了分析比较.%This paper introduce the structure and fabrication for HSGFET ozone sensors with dual sensitive layer. Study the affect of sensitive layer and structure for ozone sensitive characteristic of ozone sensors mainly. A comparison and analysis of the experimental results are given.

  19. Designations in US EPA Region 9 for the 1997 8-hour ozone (O3) national ambient air quality standards

    U.S. Environmental Protection Agency — Polygon Esri shapefile of designated areas for 8-hour ozone, for the revoked primary and secondary 1997 National Ambient Air Quality Standards (NAAQS). Nonattainment...

  20. Global Crop Yield Reductions due to Surface Ozone Exposure: Crop Production Losses and Economic Damage in 2000 and 2030 under Two Future Scenarios of O3 Pollution

    Avnery, S.; Mauzerall, D. L.; Liu, J.; Horowitz, L. W.


    Field studies demonstrate that exposure to elevated concentrations of surface ozone (O3) may cause substantial reductions in the agricultural yields of many crops. As emissions of O3 precursors rise in many parts of the world over the next few decades, yield reductions from O3 exposure may increase the challenges of feeding a global population projected to grow from approximately 6 to 8 billion people between 2000 and 2030. This study estimates global yield reductions of three key staple crops (soybean, maize, and wheat) due to surface ozone exposure in 2000 and 2030 according to two trajectories of O3 pollution: the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A2 and B1 storylines, which represent upper- and lower-boundary projections, respectively, of most O3 precursor emissions in 2030. Our results indicate that year 2000 O3-induced global yield reductions ranged, depending on the O3 exposure metric used, from 3.9-15% for wheat, 8.5-14% for soybean, and 2.2-5.5% for maize. Global crop production losses totaled 79-121 million metric tons, worth 11-18 billion annually (USD2000). In the 2030-A2 scenario we find global O3-induced yield loss of wheat to be 5.4-26% (a further reduction in yield of +1.5-10% from year 2000 values), 15-19% for soybean (reduction of +0.9-11%), and 4.4-8.7% for maize (reduction of +2.1-3.2%) depending on the metric used, with total global agricultural losses worth 17-35 billion USD2000 annually (an increase of +6-17 billion in losses from 2000). Under the 2030-B1 scenario, we project less severe but still substantial reductions in yields: 4.0-17% for wheat (a further decrease in yield of +0.1-1.8% from 2000), 9.5-15% for soybean (decrease of +0.7-1.0%), and 2.5-6.0% for maize (decrease of+ 0.3-0.5%), with total losses worth 12-21 billion annually (an increase of +$1-3 billion in losses from 2000). Because our analysis uses crop data from the year 2000, which likely underestimates agricultural

  1. Model of daytime emissions of electronically-vibrationally excited products of O3 and O2 photolysis: application to ozone retrieval

    R. O. Manuilova


    Full Text Available The traditional kinetics of electronically excited products of O3 and O2 photolysis is supplemented with the processes of the energy transfer between electronically-vibrationally excited levels O2(a1Δg, v and O2(b1Σ+g, v, excited atomic oxygen O(1D, and the O2 molecules in the ground electronic state O2(X3Σg−, v. In contrast to the previous models of kinetics of O2(a1Δg and O2 (b1Σ+g, our model takes into consideration the following basic facts: first, photolysis of O3 and O2 and the processes of energy exchange between the metastable products of photolysis involve generation of oxygen molecules on highly excited vibrational levels in all considered electronic states – b1Σ+g, a1Δg and X3Σg−; second, the absorption of solar radiation not only leads to populating the electronic states on vibrational levels with vibrational quantum number v equal to 0 – O2(b1Σ+g, v=0 (at 762 nm and O2(a1Δg, v=0 (at 1.27 µm, but also leads to populating the excited electronic–vibrational states O2(b1Σ+g, v=1 and O2(b1Σ+g, v=2 (at 689 nm and 629 nm. The proposed model allows one to calculate not only the vertical profiles of the O2(a1Δg, v=0 and O2(b1Σg, v=0 concentrations, but also the profiles of [O2(a1Δg, v≤5], [O2 (b1Σ+g , v=1, 2] and O2(X3Σg−, v=1–35. In the altitude range 60–125 km, consideration of the electronic-vibrational kinetics significantly changes the calculated concentrations of the metastable oxygen molecules and reduces the discrepancy between the altitude profiles of ozone concentrations retrieved from the 762-nm and 1.27-µm emissions measured simultaneously.

  2. What is Eating Ozone? Thermal Reactions between SO2 and O3 and Implications for the Icy Satellites

    Loeffler, Mark; Hudson, Reggie L.; Gerakines, Perry A.


    Here we present first results on a non-radiolytic, thermally-driven reaction sequence in solid H2O + SO2 + O3 mixtures at 50 – 130 K, which produces bisulfate (HSO4-). The results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making co-detection of these species unlikely. Our results also give a viable explanation for why O3 has not been detected on Callisto and why the concentration of SO2 appears to be highest in its leading hemisphere. Furthermore our results also predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. This work is supported by NASA's Outer Planets Research program.

  3. 神经网络模型在O_3浓度预测中的应用%Application of Artificial Neural Networks on the Prediction of Surface Ozone Concentrations

    沈路路; 王聿绚; 段雷


    Ozone is an important secondary air pollutant in the lower atmosphere.In order to predict the hourly maximum ozone one day in advance based on the meteorological variables for the Wanqingsha site in Guangzhou,Guangdong province,a neural network model(Multi-Layer Perceptron) and a multiple linear regression model were used and compared.Model inputs are meteorological parameters(wind speed,wind direction,air temperature,relative humidity,barometric pressure and solar radiation) of the next day and hourly maximum ozone concentration of the previous day.The OBS(optimal brain surgeon) was adopted to prune the neutral work,to reduce its complexity and to improve its generalization ability.We find that the pruned neural network has the capacity to predict the peak ozone,with an agreement index of 92.3%,the root mean square error of 0.042 8 mg/m3,the R-square of 0.737 and the success index of threshold exceedance 77.0%(the threshold O3 mixing ratio of 0.20 mg/m3).When the neural classifier was added to the neural network model,the success index of threshold exceedance increased to 83.6%.Through comparison of the performance indices between the multiple linear regression model and the neural network model,we conclud that that neural network is a better choice to predict peak ozone from meteorological forecast,which may be applied to practical prediction of ozone concentration.%O3是近地面大气中一种重要的二次污染物.本研究采用神经网络多层感知器(Multi-Layer Perceptron)和多元线性回归2种模型,以广州万顷沙站2006年的气象观测数据为输入,对该站O3的1 h平均峰值浓度进行提前1 d的预测,并比较了2种模型的预测效果.模型的输入参数为前1d O3的最高1h平均浓度和第二天的气象参数(温度、湿度、风速、风向、气压和光照).为了降低神经网络的复杂度以提高模型的泛化能力,采用了OBS(Optimal brain surgeon)方法对神经网络模型进行了修剪.结果表

  4. 浸渍法制备的Pd-MnOx/γ-Al2O3催化剂及不同载体对地表O3降解的影响%Pd-MnOx/γ-Al2O3 Monolithic Catalysts Prepared by Impregnation Method and Effect of Different Supports on Ground-Level Ozone Decomposition

    任成军; 周丽娜; 尚鸿燕; 陈耀强


    在γ-Al2O3载体上用等体积浸渍法浸渍Pd、MnOx活性组分,然后涂覆于堇青石基体上制备Pd-MnOx/γ-Al2O3整体式催化剂.分别用 X 射线衍射(XRD)、H2-程序升温还原(H2-TPR)、低温 N2吸附-脱附及 X 射线光电子能谱(XPS)对制备的催化剂进行表征.研究了Pd、MnOx浸渍顺序对催化剂活性、氧化还原性能及织构性质的影响.实验结果表明, Pd、MnOx共浸渍较分别浸渍制备的催化剂活性好, Pd 和 MnOx之间存在一定的协同作用.考察了不同载体如La-Al2O3、SiO2、γ-Al2O3和Zr-Al2O3对催化剂活性、氧化还原性能、织构性质及表面电子性能的影响.研究表明,以La-Al2O3或SiO2为载体的催化剂活性最好,即,14°C时O3转化率为82%,完全转化温度为36°C.γ-Al2O3载体次之, Zr-Al2O3载体较差.不同载体制备的催化剂中 MnOx的氧化还原性能顺序为: Pd-MnOx/SiO2>Pd-MnOx/La-Al2O3>Pd-MnOx/γ-Al2O3>Pd-MnOx/Zr-Al2O3.%Pd-MnOx/γ-Al2O3 catalysts were prepared by impregnating Pd and MnOx on γ-Al2O3 supports, using an incipient wetness impregnation method, and then coating on a cordierite substrate to obtain monolithic catalysts. The catalysts were characterized using X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), low-temperature N2 adsorption-desorption measurements, and X-ray photoelectron spectroscopy (XPS). The effects of the Pd and MnOx impregnation order on the catalytic activity, redox performance, textural properties, and surface electronic characteristics of the catalysts were studied. The experimental results showed that the activity of the catalyst co-impregnated with Pd and MnOx on γ-Al2O3 was better than that of the catalyst impregnated sequentially with Pd and MnOx. A synergetic effect was observed between Pd and MnOx on the Pd-MnOx/γ-Al2O3 catalysts for ozone decomposition. The effects of various supports on catalytic activity, redox performance, textural properties, and surface electron

  5. Acute Ozone (O3) Exposure Enhances Aortic Contraction in Healthy Rats while Exacerbating Pulmonary Injury in Diabetics

    Air pollution exposure affects health adversely in individuals with type 2 diabetes (T2D) and diet induced obesity (DIO). We hypothesized that T2D and DIO would exacerbate O3 induced pulmonary responses and alter arterial reactivity. Male Wistar and Goto Kakizaki (GK) rats, a l...

  6. The Greenhouse effect: impacts of ultraviolet-B (UV-B) radiation, carbon dioxide (CO2), and ozone (O3) on vegetation.

    Krupa, S V; Kickert, R N


    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

  7. Abatement of Polychoro-1,3-butadienes in Aqueous Solution by Ozone, UV Photolysis, and Advanced Oxidation Processes (O3/H2O2 and UV/H2O2).

    Lee, Minju; Merle, Tony; Rentsch, Daniel; Canonica, Silvio; von Gunten, Urs


    The abatement of 9 polychloro-1,3-butadienes (CBDs) in aqueous solution by ozone, UV-C(254 nm) photolysis, and the corresponding advanced oxidation processes (AOPs) (i.e., O3/H2O2 and UV/H2O2) was investigated. The following parameters were determined for 9 CBDs: second-order rate constants for the reactions of CBDs with ozone (kO3) (50% at specific ozone doses of 0.5 gO3/gDOC to ∼100% at ≥1.0 gO3/gDOC) were achieved for tetra-CBDs followed by (Z)-1,1,2,3,4-penta-CBD and hexa-CBD. This is consistent with the magnitude of the determined kO3 and k(•)OH. The formation of bromate, a potentially carcinogenic ozonation byproduct, could be significantly reduced by addition of H2O2. For a typical UV disinfection dose (400 J/m(2)), various extents of phototransformations (10-90%) could be achieved. However, the efficient formation of photoisomers from CBDs with E/Z configuration must be taken into account because of their potential residual toxicity. Under UV-C(254 nm) photolysis conditions, no significant effect of H2O2 addition on CBDs abatement was observed due to an efficient direct phototransformation of CBDs.

  8. T2 shine-through phenomena in diffusion-weighted MR imaging of lumbar discs after oxygen-ozone discolysis: a randomized, double-blind trial with steroid and O2-O3 discolysis versus steroid only.

    Perri, Marco; Grattacaso, Giuseppe; di Tunno, Valeria; Marsecano, Claudia; Gennarelli, Antonio; Michelini, Giulia; Splendiani, Alessandra; Di Cesare, Ernesto; Masciocchi, Carlo; Gallucci, Massimo


    To evaluate the discal morpho-structural changes as predictive sign in the clinical outcome after Ozone Therapy in lumbar disc herniation using the T2 shine-through effect in DWI. One hundred and fifty-four patients suffering from lumbosciatica (89 men and 65 women; range 23-62 years) were included in previous MR study performed with FSE-T2 and T2-fat, SE-T1 and DWI sequences and were randomly assigned to two groups. Seventy-seven patients (Control Group) underwent conservative treatment with intraforaminal injection of steroid and anesthetic. The remaining 77 patients (Study Group) underwent the same treatment with the addiction of oxygen-ozone (O2-O3). During the coming 6 months, an MRI follow-up with the same sequences was performed. An intervertebral disc volumetric analysis (IDVA), DWI signal score and post treatment clinical outcome evaluation were performed for an assessment of hernia reduction. χ (2) test, Student's t test and analysis of covariance were used for comparison of variables. In the Study Group, 58 over 77 patients had a successful outcome (Responders). In the Responders group, DWI T2 shine-through effect was present during MRI follow-up and in particular in 53 of 77 patients in the 6 months of follow-up (P < 0.05). Moreover, in the same group was present a statistically significant discs' shrinkage in the sixth month of follow-up (P < 0.05) as showed by IDVA. T2 shine-through effect in DWI is present before morphological disc reduction and moreover could be considered as a predictive sign of response to oxygen-ozone treatment.

  9. 中国东部地区的O3污染形成机制及趋势的初步探讨%Ozone (O3) pollution in eastern China:It’s formation and a potential air quality problem in the region

    铁学熙; 戴文婷


    Background, aim, and scopeCurrently, China is under going a rapid economic development, which results in a higher demand for energy, greater use of fossil fuels, and inevitably lead to more emission of pollutants into the atmosphere. As a result, China is experiencing heavy air pollution in the past two decades, with particle matter (PM) being one of the top pollutants. Measurements show that PM concentrations often exceed the new national ambient air quality standards of China (75 μg∙m−3 for 24 h average) in large cities in China. Aerosol particles have important impacts on photochemistry by scattering and absorbing solar and infrared radiation. In addition to aerosol particles, ozone is also a critical trace gas in the troposphere because it plays important roles in atmospheric chemistry, air quality, and climate change. Unlike other atmospheric pollutants, such as PM2.5, SO2, NOx, etc., tropospheric ozone is not directly emitted from the earth’s surface. The tropospheric ozone is photo-chemically formed through a very complicated chemical process in atmosphere. The tropospheric ozone formation is inlfuenced by its precursors (NOx, VOCs, CO), and solar radiation. The effects of ozone precursors on ozone formation in eastern China have been intensive discussed. However, the photon effect on ozone formation has not been intensively discussed, especially under the heavy PM pollution conditions in eastern China. The aim of the paper is to discuss the limitation for ozone formation under heavy PM pollution in eastern China. Materials and methodsThis study used long-term measurement of ozone, and found that there was an increase trend of ozone in Shanghai. Based on the serous haze conditions in eastern China in the recent studies, the ozone formation under the high aerosol conditions was discussed. ResultsAlthough the aerosol pollution is a major concern for the air pollution control in China at present, the O3 concentrations increase in eastern China, showing

  10. AlGaN/GaN metal-insulator-semiconductor high-electron mobility transistors with high on/off current ratio of over 5 × 1010 achieved by ozone pretreatment and using ozone oxidant for Al2O3 gate insulator

    Tokuda, Hirokuni; Asubar, Joel T.; Kuzuhara, Masaaki


    This letter describes DC characteristics of AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with Al2O3 deposited by atomic layer deposition (ALD) as gate dielectric. Comparison was made for the samples deposited using ozone (O3) or water as oxidant. The effect of pretreatment, where O3 was solely supplied prior to depositing Al2O3, was also investigated. The MIS-HEMT with O3 pretreatment and Al2O3 gate dielectric deposited using O3 as the oxidant exhibited the most desirable characteristics with an excellent high on/off current ratio of 7.1 × 1010, and a low sub-threshold swing (SS) of 73 mV/dec.

  11. O3, CH4, CO2, CO, NO2 and NMHC aircraft measurements in the Uinta Basin oil and gas region under low and high ozone conditions in winter 2012 and 2013

    S. J. Oltmans


    Full Text Available Abstract Instrumented aircraft measuring air composition in the Uinta Basin, Utah, during February 2012 and January-February 2013 documented dramatically different atmospheric ozone (O3 mole fractions. In 2012 O3 remained near levels of ∼40 ppb in a well-mixed 500–1000 m deep boundary layer while in 2013, O3 mole fractions >140 ppb were measured in a shallow (∼200 m boundary layer. In contrast to 2012 when mole fractions of emissions from oil and gas production such as methane (CH4, non-methane hydrocarbons (NMHCs and combustion products such as carbon dioxide (CO2 were moderately elevated, in winter 2013 very high mole fractions were observed. Snow cover in 2013 helped produce and maintain strong temperature inversions that capped a shallow cold pool layer. In 2012, O3 and CH4 and associated NMHCs mole fractions were not closely related. In 2013, O3 mole fractions were correlated with CH4 and a suite of NMHCs identifying the gas field as the primary source of the O3 precursor NMHC emissions. In 2013 there was a strong positive correlation between CH4 and CO2 suggesting combustion from oil and natural gas processing activities. The presence of O3 precursor NMHCs through the depth of the boundary layer in 2013 led to O3 production throughout the layer. In 2013, O3 mole fractions increased over the course of the week-long episodes indicating O3 photochemical production was larger than dilution and deposition rates, while CH4 mole fractions began to level off after 3 days indicative of some air being mixed out of the boundary layer. The plume of a coal-fired power plant located east of the main gas field was not an important contributor to O3 or O3 precursors in the boundary layer in 2013.

  12. CO2 and O3 vertical distributions over the Showa Station, Antarctica before and during the ozone hole formation in 2014, measured by balloon-borne CO2 and O3 instruments

    Miyaji, K.; Matsumi, Y.; Nakayama, T.; Ouchi, M.; Imasu, R.; Kawasaki, M.


    The vertical and horizontal distributions of CO2 mixing ratio in the troposphere and stratosphere are considered to include the information on the source and sink of CO2, as well as transport of air masses in the atmosphere. However, only a limited number of vertical profiles for CO2 mixing ratio, which were typically obtained based on aircraft-based observations, are available. We have originally developed a new balloon-born instrument (CO2 sonde) to measure CO2 vertical profile from surface up to about 10 km in altitude. The ozone hole formation is typically observed in the early spring over Antarctica. To our knowledge, no study focusing on the change in the CO2 vertical profile before and after the ozone hole formation has been reported. In the present study, we launched four CO2 sondes at Syowa Station, Antarctica between June and October in 2014 to obtain CO2 vertical distributions before and during the ozone hole formation. Observations of ozone vertical distributions using traditional ozone sondes were also conducted on the same days. In the presentation, we will report the relationships between the vertical distributions of CO2 and ozone.

  13. O3 and NOx Exchange

    Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.


    This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

  14. Breakdown maintenance of ozone monitors at automatic air quality monitoring station%空气自动监测站 O3监测仪故障维修

    鲍雷; 杨灿


    臭氧(O3)是城市环境空气中最为重要的二次污染物之一,对臭氧进行自动监测是环境管理和科学研究的要求。在长期使用臭氧自动监测仪过程中,常常可能因为仪器出现问题而影响到空气质量日报,本文以法国ESA公司O342M型O3自动监测仪为例,介绍了紫外光度法臭氧自动监测仪的原理和常见故障的维修。%Ozone is one of the most important secondary pollutants in urban ambient air .Automatic monitoring of ozone is essential for both environment management and scientific research .The operation troubles of automatic ozone monitors would always affect the daily air quality report .This paper intro-duced the basic principles of ozone monitor ,the common faults during maintenance and operation ,w hich taked example by the O342M model produced by ESA company in French .

  15. 华北平原夜间对流天气对地面 O3混合比抬升效应%Increased Mixing Ratio of Surface Ozone by Nighttime Convection Process over the North China Plain

    贾诗卉; 徐晓斌; 林伟立; 王瑛; 何心河; 张华龙


    nighttime convection process is caused by air descending from the lower to mid free-troposphere.The phenomena with ozone enhancement is also observed at an urban station in Beji-ing.In most cases when Gucheng and Beijing urban are impacted by the same convective systems,and o-zone andθse at both sites show similar trends.All above implies that ozone mixing ratio maintains around 60 ×10 -9 -80×10 -9 in the mid and lower free-troposphere over the North China Plain in summer and early autumn,and ozone increase by convective downdrafts is able to impact a large area of the North China Plain.Compared with other places,convection process causes larger ozone increase,which may exert stronger impact on the atmospheric environment.%2013年6—9月在河北省固城站观测到多次夜间对流性天气伴随地面 O3混合比快速抬升的过程,并引起次日清晨到中午 O3混合比升高。大多数对流过程中,O3混合比在半小时内升高至60×10-9~80×10-9,同时 NOx 等反应性气体混合比下降,θse 值降低,说明下沉气流将高空气团带到地面,造成了 O3混合比的升高。通过再分析资料得到下沉气团基本来源于对流层中下层,这一结论与当地进行的一次飞机观测结果吻合。多数对流过程中固城站和北京城区地面 O3混合比和θse 值有相同的变化趋势和程度。根据观测结果,推测华北地区在夏季和初秋时,对流层中下层存在 O3高值区,混合比约为60×10-9~80×10-9。对流性天气对地面 O3抬升的影响区域与对流系统的影响范围有关,可达到中尺度范围。华北地区光化学污染严重,对流性天气引起的地面 O3混合比抬升程度比较强,对环境的影响值得关注。

  16. Ground-Level Ozone Decomposition over Pd-MnOx/Al2O3 Catalyst Prepared by Urea Hydrolysis%尿素水解法制备降解地表臭氧的Pd-Mnox/Al2O3催化剂

    潘浩; 周丽娜; 朱艺; 彭娜; 龚茂初; 陈耀强


    采用尿素水解法制备了Pd-MnOx/Al2O3催化剂,运用低温N2吸附-脱附和X射线衍射对其进行了表征,并评价了其催化降解地表O3反应活性,考察了Pd,MnOx焙烧时间和MnOx含量刘催化剂活性的影响.结果表明,在高空速(660000h-1)、高相对湿度(85%~90%)条件下,MnOx焙烧时间为6h且.MnOx含量为80%的Pd-MnOx/Al2O3催化剂于低温(20~25 ℃)就表现出较高的催化活性,20℃时O3转化率就高达91.7%,其完全转化温度为24℃.可以预知该催化剂涂覆在汽车水箱散热片上,于室温就可完全降解地表O3,尤其适用于汽车冷启动和冬季时净化O3.%The Pd-MnOx/Al2O3 catalyst has been prepared by the urea hydrolysis method and characterized by Iow temperature nitrogen adsorption-desorption and X-ray diffraction. Its catalytic activity for decomposing ground-level ozone has been studied. The catalyst showed a high activity at low temperature and high relative humidity. At gas hourly space velocity (GHSV) of 660000 h-1 and relative humidity of 85%-90%, the ozone conversion over the catalyst reached 91.7% at 20 ℃ and the temperature for complete decomposition of ozone was only 24 ℃. Furthermore, the prepared catalyst can completely decompose ground-level ozone when it is coated on the wave shaped heat patches of automobile water tanks.

  17. Effect of gaseous ozone for control of stored product pests at low and high temperature

    Hansen, Lise Stengård; Hansen, Peer; Vagn Jensen, Karl-Martin


    Gaseous ozone (O3) has shown potential for control of insects in stored grain. A previous laboratory study determined doses of ozone necessary to control freely exposed and internal stages of eleven stored product pest species at 20 C. In this study the impact of temperature on the effect of ozon...

  18. Effect of operational and water quality parameters on conventional ozonation and the advanced oxidation process O3/H2O2: Kinetics of micropollutant abatement, transformation product and bromate formation in a surface water.

    Bourgin, Marc; Borowska, Ewa; Helbing, Jakob; Hollender, Juliane; Kaiser, Hans-Peter; Kienle, Cornelia; McArdell, Christa S; Simon, Eszter; von Gunten, Urs


    The efficiency of ozone-based processes under various conditions was studied for the treatment of a surface water (Lake Zürich water, Switzerland) spiked with 19 micropollutants (pharmaceuticals, pesticides, industrial chemical, X-ray contrast medium, sweetener) each at 1 μg L(-1). Two pilot-scale ozonation reactors (4-5 m(3) h(-1)), a 4-chamber reactor and a tubular reactor, were investigated by either conventional ozonation and/or the advanced oxidation process (AOP) O3/H2O2. The effects of selected operational parameters, such as ozone dose (0.5-3 mg L(-1)) and H2O2 dose (O3:H2O2 = 1:3-3:1 (mass ratio)), and selected water quality parameters, such as pH (6.5-8.5) and initial bromide concentration (15-200 μg L(-1)), on micropollutant abatement and bromate formation were investigated. Under the studied conditions, compounds with high second-order rate constants kO3>10(4) M(-1) s(-1) for their reaction with ozone were well abated (>90%) even for the lowest ozone dose of 0.5 mg L(-1). Conversely, the abatement efficiency of sucralose, which only reacts with hydroxyl radicals (OH), varied between 19 and 90%. Generally, the abatement efficiency increased with higher ozone doses and higher pH and lower bromide concentrations. H2O2 addition accelerated the ozone conversion to OH, which enables a faster abatement of ozone-resistant micropollutants. Interestingly, the abatement of micropollutants decreased with higher bromide concentrations during conventional ozonation due to competitive ozone-consuming reactions, except for lamotrigine, due to the suspected reaction of HOBr/OBr(-) with the primary amine moieties. In addition to the abatement of micropollutants, the evolution of the two main transformation products (TPs) of hydrochlorothiazide (HCTZ) and tramadol (TRA), chlorothiazide (CTZ) and tramadol N-oxide (TRA-NOX), respectively, was assessed by chemical analysis and kinetic modeling. Both selected TPs were quickly formed initially to reach a

  19. Chronic drought stress reduced but not protected Shantung maple (Acer truncatum Bunge) from adverse effects of ozone (O3) on growth and physiology in the suburb of Beijing, China.

    Li, Li; Manning, William J; Tong, Lei; Wang, Xiaoke


    A two-year experiment exposing Acer truncatum Bunge seedlings to elevated ozone (O3) concentrations above ambient air (AO) and drought stress (DS) was carried out using open-top chambers (OTCs) in a suburb of Beijing in north China in 2012-2013. The results suggested that AO and DS had both significantly reduced leaf mass area (LMA), stomatal conductance (Gs), light saturated photosynthetic rate (Asat) as well as above and below ground biomass at the end of the experiment. It appeared that while drought stress mitigated the expression of foliar injury, LMA, leaf photosynthetic pigments, height growth and basal diameter, due to limited carbon fixation, the O3 - induced reductions in Asat, Gs and total biomass were enhanced 23.7%. 15.5% and 8.1% respectively. These data suggest that when the whole plant was considered that drought under the conditions of this experiment did not protect the Shantung maple seedlings from the effects of O3.

  20. Experimental Study on Advanced Treatment of Semi-coking Wastewater by Ozone Catalytic Oxidation%O3催化氧化深度处理兰炭废水的试验研究

    孟庆锐; 安路阳; 李超; 王春旭; 王钟欧


    A new method of advanced treatment of semi-coking wastewater by ozone catalytic oxidation was proposed.CuO/γ-Al2O3 was prepared by impregnation with copper nitrate and alumina carrier, then characterized by XRD.Using the catalyst process the semi-coking wastewater after biochemical treatment by ozone catalytic oxidation.Experimental device was designed and influencing factors for COD removal efficiency such as amount of catalyst used, reaction time, amount of ozone used, sewage pH value and other factors were investigated.Experimental results showed that pH under acidic condition is helpful to better COD removal efficiency, improving the amount of ozone can contribute COD removal efficiency, and control catalyst dosage and reaction time within a certain range conductive to the removal of contaminants.When the catalytic process condition were as amount of CuO/γ-Al2O3 300 g, amount of ozone used 0.08 m3/h and pH in sewage 7 and the reaction time 1 h, the removal rate of COD from sewage was expected to reach 95%.The catalyst also exhibits the excellent activity and stability in 20times reaction of ozone catalytic oxidation.%采用O3催化氧化法深度处理兰炭废水,提出了兰炭废水达标排放的新处理方法.以铜为活性组分,氧化铝为载体采用浸渍法制备CuO/γ-AlO3催化剂,并采用XRD对其进行表征,利用催化剂结合O3催化氧化法去除兰炭废水中经生化处理后残留的污染物.设计了催化氧化试验装置,考察了催化剂投加量、反应时间、O3用量以及pH等因素对处理效果的影响.实验结果表明,pH在酸性条件下有利于COD去除率的提高,O3用量提高有助于COD去除率的提高,将催化剂用量和反应时间控制在一定范围内有利于污染物的去除;最佳条件下催化剂投加量300 g,反应时间1h,O3用量0.08 m3/h,pH为7左右时COD去除率可达到95%左右.另外,催化剂在20次反应过程中表现出较高的催化活性及较强的稳定性.

  1. Tropospheric O3 over Indonesia during biomass burning events measured with GOME (Global Ozone Monitoring Experiment) and compared with backtrajectory calculation

    Ladstaetter-Weissenmayer, A.; Meyer-Arnek, J.; Burrows, J. P.

    During the dry season, biomass burning is an important source of ozone precursors for the tropical troposphere, and ozone formation can occur in biomass burning plumes originating in Indonesia and northern Australia. Satellite based GOME (Global Ozone Measuring experiment) data are used to characterize the amount of tropospheric ozone production over this region during the El Niño event in September 1997 compared to a so called "normal" year 1998. Large scale biomass burning occurred over Kalimantan in 1997 caused by the absence of the northern monsoon rains, leading to significant increases in tropospheric ozone. Tropospheric ozone was determined from GOME data using the Tropospheric Excess Method (TEM). Backtrajectory calculations show that Indonesia is influenced every summer by the emissions of trace gases from biomass buring over northern Australia. But in 1997 over Indonesia an increasing of tropospheric ozone amounts can be observed caused by the fires over Indonesia itself as well as by northern Australia. The analysis of the measurements of BIBLE-A (Biomass Burning and Lightning Experiment) and using ATSR (Along the Track Scanning Radiometer) data show differences in the view to the intensity of fire counts and therefore in the amount of the emission of precursors of tropospheric ozone comparing September 1997 to September 1998.

  2. 常温下 MnO2/Al2O3催化剂催化臭氧氧化甲苯反应%Room Temperature Catalytic Ozonation of Toluene over MnO2/Al2O3

    龙丽萍; 赵建国; 杨利娴; 付名利; 吴军良; 黄碧纯; 叶代启


    Five kinds of transition metal oxides supported on alumina and prepared by wetness impregnation were evaluated for the catalytic ozonation of toluene at room temperature and characterized by temperature-programmed reduction, temperature-programmed oxidation, N2 adsorption-desorption, and X-ray photoelectron spectroscopy. The catalysts with a lower reduction temperature and less H2 consumption showed a higher efficiency for ozone and toluene decomposition, such as NiO/Al2O3, CoO/Al2O3, and MnO2/Al2O3, while lower efficiency were observed on Fe2O3/Al2O3 and CuO/Al2O3. Toluene decomposition efficiency was obviously dependent on ozone. Because of the low ozone to toluene concentration ratio, a CO2 yield of less than 30% was obtained. At a toluene concentration of 666 mg/m3 and an ozone concentration between 193 and 965 mg/m3, toluene conversion was found to vary from 15.2% to 46.7%. Additionally, we observed an increase in oxidation products and lattice oxygen on the catalyst surface. A preliminary investigation into the reaction pathway was undertook by in situ diffuse reflectance Fourier transform infrared spectroscopy. With regards to the formation of COO-, C=O, and C-O groups the high ozone concentration accelerated the transformation from COO- to C=O and C-O. The substance containing COO-remained unchanged at 573 K, while the substances containing C=O and C-O underwent oxidation at higher than 373 K. A possible reaction pathway is proposed based on these findings.%采用浸渍法制备了Al2O3负载的5种过渡金属氧化物催化剂,考察了它们在常温下催化臭氧氧化甲苯的性能,并运用程序升温还原、程序升温氧化、N2吸附-脱附和X射线光电子能谱对催化剂进行了表征.结果表明,NiO/Al2O3,CoO/Al2O3和MnO2/Al2O3催化剂上活性氧中心数量较少,臭氧与甲苯转化率较高;而Fe2O3/Al2O3和CuO/Al2O3催化剂上则相反.催化降解臭氧效率较高的催化剂上甲苯转化率也较高,在本文实

  3. Diurnal ozone cycle in the tropical and subtropical marine boundary layer

    Laat, A.T.J. de; Lelieveld, J.


    A conceptual analysis of diurnal ozone (O3 ) changes in the marine boundary layer (MBL) is presented. Such changes are most pronounced downwind of O3 sources in tropical and subtropical latitudes, and during summer at higher latitudes. Previously, it has been assumed that daytime photochemical O3

  4. MnOx/介孔γ-A12O3催化臭氧化降解水中安替比林的研究%Catalytic ozonation of phenazone on MnOx/mesoporous γ-A12O3 in water

    杨力; 聂玉伦; 胡春; 马刚; 李礼


    以自制的介孔γ-A12O3为载体,通过等体积浸渍法合成了MnOx/介孔γ-A12O3催化剂。采用X射线衍射(XRD)、透射电镜(TEM)以及紫外一可见漫反射(uV—VisDRS)等手段对其进行表征。结果表明,锰氧化物在介孔氧化铝载体上具有较高的分散度,并且锰以多种价态存在。高度分散以及多价态的MnOx能够提高催化臭氧化过程中电荷转移,引起更高的催化活性。MnOx/介孑γ-A12O3催化剂能够有效地提高臭氧对水中安替比林的矿化效果,对含量为10mg/L的安替比林水溶液在反应60min后基本达到完全矿化。%MnOJmesoporous γ-A12O3 was prepared by impregnation method using synthetic mesoporous γ-A12O3 as the support. The obtained catalyst was characterized by X-ray diffraction (XRD) , transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectra (UV-Vis DRS). The results reveal that MnOxis highly dispersed on mesoporous γ-A12O3 and exists as the muhivalenee oxidation states. The high dispersion and multivalence oxidation states of MnOx enhance the interfacial electron transfer in the ozonation process, resulting in the higher catalytic activity. The presence of MnOx/mesoporous γ-A12O3 catalyst significantly improves the mineralization efficiency of phenazone aqueous solution compared to non-catalytic ozonation. The total organic carbon (TOC) of the solution is almost completely removed at 60 rain at the phenazone concentration of 10 mg/L.

  5. Negative ion photoelectron spectra of ISO3-, IS2O3-, and IS2O4- intermediates formed in interfacial reactions of ozone and iodide/sulfite aqueous microdroplets

    Qin, Zhengbo; Hou, Gao-Lei; Yang, Zheng; Valiev, Marat; Wang, Xue-Bin


    Three short-lived, anionic intermediates, ISO3-, IS2O3-, and IS2O4-, are detected during reactions between ozone and aqueous iodine/sulfur oxide microdroplets. These species may play an important role in ozone-driven inorganic aerosol formation; however their chemical properties remain largely unknown. This is the issue addressed in this work using negative ion photoelectron spectroscopy (NIPES) and ab initio modeling. The NIPE spectra reveal that all of the three anionic species are characterized by high adiabatic detachment energies (ADEs) - 4.62 ± 0.10, 4.52 ± 0.10, and 4.60 ± 0.10 eV for ISO3-, IS2O3-, and IS2O4-, respectively. Vibrational progressions with frequencies assigned to the S-O symmetric stretching modes are discernable in the ground state transition features. Density functional theory calculations show the presence of several low-lying isomers involving different bonding scenarios. Further analysis based on high level CCSD(T) calculations reveal that the lowest energy structures are characterized by the formation of I-S and S-S bonds and can be structurally viewed as SO3 linked with I, IS, and ISO for ISO3-, IS2O3-, and IS2O4-, respectively. The calculated ADEs and vertical detachment energies are in excellent agreement with the experimental results, further supporting the identified minimum energy structures. The obtained intrinsic molecular properties of these anionic intermediates and neutral radicals should be useful to help understand their photochemical reactions in the atmosphere.

  6. Ground-based measurements of O3, NO2, OClO, and BrO during the 1987 Antarctic ozone depletion event

    Sanders, R. W.; Solomon, S.; Carroll, M. A.; Schmeltekopf, A. L.


    Near-ultraviolet absorption spectroscopy in the wavelength range from 330 to 370 nm was used to measure O3, NO2, OClO, and BrO at McMurdo Station (78S) during 1987. Visible absorption measurements of O3, NO2, and OClO were also obtained using the wavelength range from about 403 to 453 nm. These data are described and compared to observations obtained in 1986. It is shown that comparisons of observations in the two wavelength ranges provide a sensitive measure of the altitude where the bulk of atmospheric absorption takes place.

  7. Fe-Al/Al2O3催化臭氧化去除水中有机污染物2,4-D过程中溴酸盐的生成控制研究%Inhibition of bromate formation during catalytic ozonation of organic pollutant 2,4-D in bromide-containing water over Fe-Al/Al2O3

    李能能; 聂玉伦; 胡春


    Fe-Al supported on γ-Al2O3 (Fe-Al/Al2O3) was prepared via impregnation method followed by hydrolysis and hydrothermal treatment.Based on characterization of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS),Fe3 + and Fe2 + coexisted-in Fe-Al/Al2O3 while Al was in the state of Al2O3 and AlOOH.In comparison with ozonation alone,the addition of Fe-A1/Al2O3 resulted in complete inhibition of BrO3-formation with higher efficiency for catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D).Moreover,the catalyst could be reused for six times without significant loss of activity,indicating Fe-Al/Al2O3 has an excellent long-term stability.The effects of ozone dose and bromide concentration on TOC removal and bromate formation were also studied.The results showed that no significant bromate formation was found in catalytic ozonation process over FeAl/Al2O3 even with the increased ozone dose and bromide concentration,whereas the increase of ozone dose could result in higher TOC removal efficiency.%采用浸渍、强化水解和后续水浴加热的方法制得催化剂Fe-Al/Al2O3,并通过XRD和XPS等表征手段对其结构性能进行了研究.结果表明,催化剂中铁是以二价和三价存在,且以三价铁为主;铝则以Al2O3和AlOOH形态存在.与单独臭氧化相比,Fe-Al/Al2 O3既能高效矿化水中的难降解有机物2,4-二氯苯氧乙酸(2,4-D),又能明显抑制溴酸盐的生成,体现出很好的循环使用稳定性.进一步探讨了臭氧投加量和溴离子初始浓度对催化臭氧化效率和溴酸盐生成的影响.研究表明,在Fe-Al/Al2O3催化臭氧化过程中,水中溴酸盐浓度受臭氧投加量和溴离子初始浓度的影响较小,均可明显抑制溴酸盐的生成,且有机物的矿化效率随着臭氧投加量的增加而显著提高.

  8. High spectral resolution ozone absorption cross-sections – Part 1: Measurements, data analysis and comparison with previous measurements around 293 K

    V. Gorshelev


    Full Text Available In this paper we discuss the methodology of taking broadband relative and absolute measurements of ozone cross-sections including uncertainty budget, experimental set-ups, and methods for data analysis. We report on new ozone absorption cross-section measurements in the solar spectral region using a combination of Fourier transform and echelle spectrometers. The new cross-sections cover the spectral range 213–1100 nm at a spectral resolution of 0.02–0.06 nm in the UV-vis and 0.12–0.24 nm in the IR at eleven temperatures from 193 to 293 K in steps of 10 K. The absolute accuracy is better than three percent for most parts of the spectral region and wavelength calibration accuracy is better than 0.005 nm. The new room temperature cross-sections data are compared in detail with previously available literature data. The temperature dependence of our cross-sections is described in a companion paper.

  9. V2O5-TiO2-AlF3/Al2O3催化臭氧化2,4-滴丙酸的氧化效能%Oxidative efficiency of ozonation of 2-(2,4-dichlorophenoxy)propionic acid in the presence of V2O5-TiO2-AlF3/Al2O3

    蓝小飞; 曹利刚; 恽正兴; 童少平


    A novel tri-components catalyst characterized as V2O5-TiO2-AlF3/Al2O3 by XRD was prepared via incipient wetness impregnation to promote ozonation efficiency.The activity of the catalyst in ozonation was evaluated by degradation of 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP).The results showed that the catalyst could greatly improve the efficiency of ozonation of 2,4-DP.The test of tert-butyl alcohol addition indicated that the catalytic ozonation of 2,4-DP might follow a hydroxyl radical-type mechanism.The Rct value of the catalytic ozonation calculated by the relative method was larger than that of ozonation alone.The repeated test indicated that the catalyst remained relatively stable in the catalytic ozonation of 2,4-DP.The above results are of great significance for extending application of catalytic ozonation of advanced oxidation process in wastewater treatment.%为了提高有机物的臭氧化降解效率,工作中利用浸渍法制备了一种新型的三组分催化剂(记为V2O5-TiO2-AlF3/Al2O3).催化臭氧化降解2,4-滴丙酸的实验结果表明,该催化剂能有效提高臭氧化的效率,体系可能遵循羟基自由基的作用机理.利用相对法计算结果表明,与单独臭氧化相比,V2O5-TiO2-AlF3/Al2O3催化臭氧化体系具有更大的Rct值.重复实验结果表明,该催化剂具有相对较好的稳定性.以上研究结果对推广催化臭氧化技术在实际废水处理中的应用具有重要的实际意义.

  10. Aerobic biological treatment of olive mill wastewater previously treated by an ozonization stage; Tratamiento biologico aerobico del alpechin depurado previamente con ozono

    Beltran de Heredia Alonso, J.; Torregrosa Anton, J.; Garcia Rodriguez, J.; Ramos Viseas, M. P.; Dominguez Vargas, J. R. [Universidad de Extremadura. Badajoz (Spain)


    In the present work, the degradation of olive mill wastewaters previously treated by an ozonation stage has been studied by an aerobic biological oxidation. The substrate evolution (based on chemical oxygen demand), biomass (measured as volatile suspended solids) and total polyphenolic contents were followed during each experiment. A kinetic study is performed by using the Contois model, which applied to the experimental data, provides the specific kinetic parameters of this model. The deduced kinetic equation for the consume of substrate is q=17.0 S/(18.2 X + So X) g COD/ gVSS day. Moreover, others interesting biological parameters like the cellular yied coefficient and the kinetic rate constant for the endogenous metabolism were determined, obtaining a values of 0.214 g VSS/g COD and 0.167 day''-1, respectively. (Author) 29 refs.

  11. 大气O3浓度升高对毛竹光合生理的影响%Impacts of elevated atmospheric ozone concentration on the photosynthetic physiology of Phyllostachys edulis

    李迎春; 李应; 陈双林; 庄明浩; 郭子武; 杨清平


    In this study, open-top chambers (OTCs) were employed to approach the impacts of elevated atmospheric ozone ( O3) concentration on the photosynthesis of Phyllostachys edulis. Five treatments were installed, i. e. , CF (background atmosphere after filtrated by activated car-bon, 22-25 nL·L-1) , NF (directly introduce the background atmosphere to the gas chamber, 40-45 nL·L-1) , T, (92-106 nL·L-1 of O3, averagely 100 nL·L-1) , T2( 142-160 nL·L-1 of O3, averagely 150 nL·L-1). Under different O3 concentrations, the diurnal variations of P. edulis leaf Pn and Tr represented one-peak curves. With the increasing concentration of O3, the diurnal variations of the leaf Gs, Ci, and Ls trended to be simplified, while that of WUE be-came stable gradually. Under higher concentrations (≥100 nL·L-1)O3, the diurnal means of Pn, Ls, and WUE and the contents Chl, Chl-a, Chl-b, and Car decreased significantly, those of Gs and Tr had a significant increase, while the diurnal mean of Ci and the composition of photo-synthetic pigment changed less. In treatments T1 and T2, the Pn, Tr, and Gs were significantly correlated with the environmental factors FpdL, Tair, Ca and RH, and the Pn and Tr were signifi-cantly correlated with the PPED while the Gs was less correlated with the PPED. All the results indicated that 100 and 150 nL·L-1 of O3 could induce the leaf stomatal or non-stomatal limita-tion of P. edulis, respectively, and the stoma became insensitive to the environment, which im-pacted the leaf' s normal feedback mechanisms, increased leaf evapotranspiration, and inhibited the degradation or synthesis of photosynthetic pigments, exerting serious negative effects on the photosynthesis and dry matter accumulation of P. edulis.%以毛竹(phyllostachys edulis)为试材,运用开顶式气室(OTCs)模拟了4个大气O3浓度情景,分别为CF(背景大气经活性炭过滤后的处理,22~25 nL·L-1)、NF(直接将背景大气输入气室内,40~45 nL·L-1)、T1(O3

  12. Development and evaluation of an ozone deposition scheme for coupling to a terrestrial biosphere model

    Franz, Martina; Simpson, David; Arneth, Almut; Zaehle, Sönke


    Ozone (O3) is a toxic air pollutant that can damage plant leaves and substantially affect the plant's gross primary production (GPP) and health. Realistic estimates of the effects of tropospheric anthropogenic O3 on GPP are thus potentially important to assess the strength of the terrestrial biosphere as a carbon sink. To better understand the impact of ozone damage on the terrestrial carbon cycle, we developed a module to estimate O3 uptake and damage of plants for a state-of-the-art global terrestrial biosphere model called OCN. Our approach accounts for ozone damage by calculating (a) O3 transport from 45 m height to leaf level, (b) O3 flux into the leaf, and (c) ozone damage of photosynthesis as a function of the accumulated O3 uptake over the lifetime of a leaf. A comparison of modelled canopy conductance, GPP, and latent heat to FLUXNET data across European forest and grassland sites shows a general good performance of OCN including ozone damage. This comparison provides a good baseline on top of which ozone damage can be evaluated. In comparison to literature values, we demonstrate that the new model version produces realistic O3 surface resistances, O3 deposition velocities, and stomatal to total O3 flux ratios. A sensitivity study reveals that key metrics of the air-to-leaf O3 transport and O3 deposition, in particular the stomatal O3 uptake, are reasonably robust against uncertainty in the underlying parameterisation of the deposition scheme. Nevertheless, correctly estimating canopy conductance plays a pivotal role in the estimate of cumulative O3 uptake. We further find that accounting for stomatal and non-stomatal uptake processes substantially affects simulated plant O3 uptake and accumulation, because aerodynamic resistance and non-stomatal O3 destruction reduce the predicted leaf-level O3 concentrations. Ozone impacts on GPP and transpiration in a Europe-wide simulation indicate that tropospheric O3 impacts the regional carbon and water cycling less

  13. Degradation of chloramphenicol in aqueous solution using ozone oxidation in a two-phase system of water/loaded ozone organic solvent%水/载O3有机溶剂两相臭氧氧化法降解水体中氯霉素

    李时银; 史震宇; 陆继来; 邹敏; 张利民


    Using a two-phase system of water/perfluorodecalin organic solvent loaded ozone, degradation of chloramphenicol in aqueous solution was conducted. Due to perfluorodecalin has a high ozone stability and solubility, chloramphenicol was used to examine the efficiency of the two-phase ozonation system. During the experiments, effects of initial pH and free radical scavenger on the removal rate of chloramphenicol were investigated respectively. The results showed that the efficiency of two-phase ozonation was increased with the increase of initial pH in water. It was also observed that free radical scavenger had no significant negative effect in two-phase ozonation.%以水/载O3有机溶剂(全氟萘烷)为新型两相臭氧氧化体系,研究了臭氧在全氟萘烷中的溶解度和稳定性,并考察了pH、NaHCO3和叔丁醇对两相体系中臭氧稳定性的影响;以水体中氯霉素为研究对象,考察了初始pH值和自由基抑制剂对两相臭氧氧化体系降解氯霉素效果的影响.结果表明:初始水相pH增大有利于氯霉素的降解;自由基抑制剂对两相体系氧化降解氯霉素影响不显著.

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

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


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

  15. Summertime surface O3 behavior and deposition to tundra in the Alaskan Arctic

    Van Dam, Brie; Helmig, Detlev; Doskey, Paul V.; Oltmans, Samuel J.


    Atmospheric turbulence quantities, boundary layer ozone (O3) levels, and O3 deposition to the tundra surface were investigated at Toolik Lake, AK, during the 2011 summer season. Beginning immediately after snowmelt, a diurnal cycle of O3 in the atmospheric surface layer developed with daytime O3 maxima, and minima during low-light hours, resulting in a mean amplitude of 13 ppbv. This diurnal O3 cycle is far larger than observed at other high Arctic locations during the snow-free season. During the snow-free months of June, July, and August, O3 deposition velocities were ˜3 to 5 times faster than during May, when snow covered the ground most of the month. The overall mean O3 deposition velocity between June and August was 0.10 cm s-1. The month of June had the highest diurnal variation, with a median O3 deposition velocity of 0.2 cm s-1 during the daytime and 0.08 cm s-1 during low-light conditions. These values are slightly lower than previously reported summertime deposition velocities in northern latitudes over tundra or fen. O3 loss during low-light periods was attributed to a combination of surface deposition to the tundra and stable boundary layer conditions. We also hypothesize that emissions of reactive biogenic volatile organic compounds into the shallow boundary layer may contribute to nighttime O3 loss.

  16. Air pollution by ozone in Europe in summer 2003 - Overview of exceedances of EC ozone threshold values during the summer season April-August 2003 and comparisons with previous years

    Fiala, J.; Cernikovsky, L.; Leeuw, F. de; Kurfuerst, P.; Aalst, R. van (eds.)


    In the period 1995-2003 of reporting tinder the old ozone directive, there has been little or no change in the reported exceedances of ozone threshold values. This is not unexpected as reductions in the EU emissions of nitrogen oxides and nonmethane volatile organic compounds, the main ozone precursors, have so far been limited - about 30 % between 1990 and 2000. 2010 under the national emission teilings directive. While peak ozone concentrations seem to go down, ozone concentration statistics relevant to the target values set in the new ozone directive show little or no reduction in the period 1996-2000. Very few stations actually show a significant downward trend for these stabstics. The threshold for warning the population continues to be exceeded on a few occasions Bach year, while the threshold for informing the population is exceeded at riost stations in most countries (outside northern Europe and Ireland) each year, generally more so in warm summers. These exceedances are likely to retur in years with temperatures above the long-term average until there is a substantially larger decrease in precursor emissions. A further reduction of about 30 % is foreseen towards Under current legislation and with the rate of turnover of the vehicle fleet, furtber reductions will gradually occur towards 2010, and further reductions may be necessary to achieve the target values of the new ozone directive. Note that, due to the uncertainties caused by year-to-year meteorological variations and the changes in the monitoring station configuration, these conclusions are tentative. (au)

  17. Results from a new linear O3 scheme with embedded heterogeneous chemistry compared with the parent full-chemistry 3-D CTM

    W. Feng


    Full Text Available A detailed full-chemistry 3-D chemistry and transport model (CTM is used to evaluate the current stratospheric O3 parameterisation in the European Centre for Medium-Range Weather Forecasts (ECMWF model and to obtain an alternative version of the ozone scheme implicitly including heterogeneous chemistry. The approach avoids the inaccurate treatment currently given to heterogeneous ozone chemistry in the ECMWF model, as well as the uncertainties of a cold-tracer. The new O3 scheme (COPCAT is evaluated within the same CTM used to calculate it. It is the first time such a comparison has been possible, providing direct information on the validity of the linear parameterisation approach for stratospheric ozone. Simulated total column and O3 profiles are compared against Total Ozone Mapping Spectrometer (TOMS and Halogen Occultation Experiment (HALOE observations. COPCAT successfully simulates polar loss and reproduces a realistic Antarctic O3 hole. The new scheme is comparable to the full-chemistry in many regions for multiannual runs. The parameterisation produces less ozone over the tropics around 10 hPa, compared to full-chemistry and observations, however, this problem can be ameliorated by choosing a different ozone climatology for the scheme. The new scheme is compared to the current ECMWF scheme in the same CTM runs. The Antarctic O3 hole with the current ECMWF scheme is weaker and disappears earlier than with the new COPCAT scheme. Differences between the current ECMWF scheme and COPCAT are difficult to explain due to the different approach used for heterogeneous chemistry and differences in the photochemical models used to calculate the scheme coefficients. Results with the new COPCAT scheme presented here show that heterogeneous and homogeneous ozone chemistry can be included in a consistent way in a linear ozone parameterisation, without any additional tunable parameters, providing a parameterisation scheme in much better agreement with the

  18. Charge transfer and interfacial magnetism in (LaNiO3)n/(LaMnO3)2 superlattices

    Hoffman, Jason; Tung, I. C.; Nelson-Cheeseman, Brittany; Liu, Ming; Freeland, John; Bhattacharya, Anand


    (LaNiO3)n/(LaMnO3)2 superlattices were grown using ozone-assisted molecular beam epitaxy, where LaNiO3 is a paramagnetic metal and LaMnO3 is an antiferromagnetic insulator. The superlattices exhibit excellent crystallinity and interfacial roughness of less than 1 unit cell. X-ray spectroscopy and dichroism measurements indicate that electrons are transferred from the LaMnO3 to the LaNiO3, inducing magnetism in LaNiO3. Magnetotransport measurements reveal a transition from metallic to insulati...

  19. Studies on the biological effects of ozone: 10. Release of factors from ozonated human platelets.

    Valacchi, G; Bocci, V


    In a previous work we have shown that heparin, in the presence of ozone (O3), promotes a dose-dependent platelet aggregation, while after Ca2+ chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF), transforming growth factor beta1 (TGF-beta1) and interleukin-8 (IL-8) are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limb ischemia treated with O3 autohaemoteraphy (O3-AHT).

  20. Studies on the Biological Effects of Ozone: 10. Release of Factors from Ozonated Human Platelets

    G. Valacchi


    Full Text Available In a previous work we have shown that heparin, in the presence of ozone (O3, promotes a dose-dependent platelet aggregation, while after Ca2+ chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF, transforming growth factor β1 (TGF-β1 and interleukin-8(IL-8 are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limbischemia treated with O3 autohaemoteraphy (O3-AHT.

  1. Ozone therapy: A clinical review

    Elvis, A. M.; Ekta, J. S.


    Ozone (O3) gas discovered in the mid-nineteenth century is a molecule consisting of three atoms of oxygen in a dynamically unstable structure due to the presence of mesomeric states. Although O3 has dangerous effects, yet researchers believe it has many therapeutic effects. Ozone therapy has been utilized and heavily studied for more than a century. Its effects are proven, consistent, safe and with minimal and preventable side effects. Medical O3 is used to disinfect and treat disease. Mechan...

  2. Multivariate analysis of physiological parameters reveals a consistent O3 response pattern in leaves of adult European beech (Fagus sylvatica).

    Löw, Markus; Deckmyn, Gaby; Op de Beeck, Maarten; Blumenröther, Manuela C; Oßwald, Wolfgang; Alexou, Maria; Jehnes, Sascha; Haberer, Kristine; Rennenberg, Heinz; Herbinger, Karin; Häberle, Karl-Heinz; Bahnweg, Günther; Hanke, David; Wieser, Gerhard; Ceulemans, Reinhart; Matyssek, Rainer; Tausz, Michael


    • Increasing atmospheric concentrations of phytotoxic ozone (O(3) ) can constrain growth and carbon sink strength of forest trees, potentially exacerbating global radiative forcing. Despite progress in the conceptual understanding of the impact of O(3) on plants, it is still difficult to detect response patterns at the leaf level. • Here, we employed principal component analysis (PCA) to analyse a database containing physiological leaf-level parameters of 60-yr-old Fagus sylvatica (European beech) trees. Data were collected over two climatically contrasting years under ambient and twice-ambient O(3) regimes in a free-air forest environment. • The first principal component (PC1) of the PCA was consistently responsive to O(3) and crown position within the trees over both years. Only a few of the original parameters showed an O(3) effect. PC1 was related to parameters indicative of oxidative stress signalling and changes in carbohydrate metabolism. PC1 correlated with cumulative O(3) uptake over preceding days. • PC1 represents an O(3) -responsive multivariate pattern detectable in the absence of consistently measurable O(3) effects on individual leaf-level parameters. An underlying effect of O(3) on physiological processes is indicated, providing experimental confirmation of theoretical O(3) response patterns suggested previously.

  3. Analysis on the change of ozone concentration in Nansha district of Guangzhou and it relationship with meteorological factors%广州南沙区O3浓度变化及其与气象因子的关系

    王开燕; 邓雪娇; 张剑; 李菲; 邓涛; 麦博儒


    Base on the Os concentration and meteorological data collected in 2010 at Nansha meteorological observation base, the variation characteristics of O3 concentration and it relationship with meteorological lactors are researched. The results show that the maximum hourly average O3 concentration was found in August and the most excessive hours were found in September. The diurnal variation of O3 was distributed in mono-peak pattern. The diurnal changes was biggest in autumn, which was followed by summer, spring and winter, the seasonal change of ozone was autumn>spring>summer>winter. Temperature, relative humidity, cloud cover are the main meteorological factors that influence Os concentration. O3 concentration is the highest in autumn when Oa was mainly produced by local photochemistry reaction; ozone in spring, summer and winter was mainly transportation from outside. Backward trajectory analysis shows that in the autumn air-mass is mainly from the continent, while in trie spring, summer and winter, air-mass is mainly from the southeastern coast or relative clean South China sea.%利用广州南沙区气象探测基地2010年O3浓度和常规气象观测资料,分析了O3浓度变化特征及其气象因子的关系.结果表明,广州南沙区2010年O3浓度最高时均值的最大值出现在8月,超标时数最多的是9月;O3浓度日变化呈单峰型分布,O3浓度日变化最大的季节是秋季,其次为夏季、春季、冬季;O3浓度呈现秋季>春季>夏季>冬季的变化特征.气温、相对湿度、日照时数和云量与O3浓度相关系数大,是影响南沙O3浓度的主要气象因子.秋季O3浓度高,O3主要以局地光化学反应生成为主;春季、夏季和冬季O3主要以外来源的输送为主.气团后向轨迹分析表明南沙区秋季气团主要来自污染的大陆地区,春季、夏季和冬季气团主要是来自东南沿海附近或较为清洁的南海.

  4. O3 Nanoparticles

    Wang, Juan


    Ti2O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time. Benefiting from the nanosize and narrow-bandgap features, the Ti2O3 nanoparticles possess strong light absorption and nearly 100% internal solar–thermal conversion efficiency. Furthermore, Ti2O3 nanoparticle-based thin film shows potential use in seawater desalination and purification.

  5. 2006~2012年珠江三角洲地区O3污染对人群健康的影响%Human health impact of exposure to ozone pollutant in Pearl River Delta region during 2006~2012

    廖志恒; 范绍佳


    Comprehensive exposure-response coefficients were obtained based on Meta-analysis of epidemiologic studies, and then by using ozone concentration data from Pearl River Delta regional air quality monitoring network, human health impacts of ozone pollutant in Pearl River Delta region during 2006~2012were assessed based on Relative Risk Model. The results of Meta-analysis show that as the concentration of ozone increased 10µg/m3, the mortality for non-accidental, cardiovascular disease and respiratory disease increased 0.45% (95% confidence interval (CI): 0.40%~0.50%), 0.70% (95% CI: 0.57%~0.86%) and 0.64% (95% CI: 0.47%~0.86%), respectively. Health impact assessments indicate that due to the growth of ozone concentration and exposed population, the ozone-attributable mortality was on the 3times rise from 2006 to 2012, and the rising ozone concentration had contributed more than 2/3 of the mortality increment. The estimated annual average numbers of attributable mortality of non-accidental, cardiovascular disease and respiratory disease were 3982 (95% CI: 3543~4420), 1894 (95% CI: 1546~2319) and 1128 (95% CI: 830~1508), respectively. Sensitivity analysis reveals that the mortality estimation appeared large deviation as parameter change, demonstrating urgent request of more accuracy parameters.%通过检索国内流行病学研究成果,Meta分析得到综合的暴露-反应系数后,利用粤港珠江三角洲区域空气监控网络监测的O3浓度,基于相对危险度模型对2006~2012年珠江三角洲地区归因于O3污染的人群健康影响进行评估. Meta分析结果表明, O3浓度每升高10µg/m3,非意外死亡率、心血管疾病死亡率和呼吸系统疾病死亡率分别上升0.45%(95%置信区间CI:0.40%~0.50%)、0.70%(95% CI:0.57%~0.86%)和0.64%(95% CI:0.47%~0.86%).人群健康影响评估表明,由于暴露人口和O3浓度的增加,珠江三角洲地区归因O3污染的死亡人数呈上升趋势,2012年归因死亡人数约为2006

  6. Ozone decomposition

    Batakliev Todor


    Full Text Available Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers. Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates

  7. Wastewater treatment by oxidation with ozone.

    Edna de Almeida; Márcia Regina Assalin; Maria Aparecida Rosa; Nelson Durán


    A large variety of organic and inorganic compounds may be found in wastewater which can contribute to environmental contamination. Oxidation processes with ozone (O3; O3/UV; O3/H2O2; O3/TiO2; O3/Mn+2) and the use of ozone in the pre- or post-treatment of wastewater combined with biological processes has been extensively studied for the treatment of effluents. The aim of this work was to evaluate the potential of the ozonation process in the treatment of several industrial wastewaters, namely ...


    陈巧俊; 王雪梅; 吴志勇; 王志铭


    In this study, a new generation of fully-coupled meteorology and atmospheric chemistry (Weather Research and Forecasting-Chemistry model, WRF-Chem) model is used to simulate the impacts of urban expansion on major meteorological variables and ozone concentration in spring over the Pearl River Delta (PRD). Results showed that urban expansion increases monthly-averaged 2 m air temperature in urban areas by 0.35 ℃. In urban areas, the relative humidity decreases by 4%-6%, especially during nighttime. Higher roughness elements in urban areas reduce daytime and nighttime wind speed, leading to a decrease of 1.89 m/s in monthly urban-averaged 10-m wind speed. The same dynamic effect generates more vigorous daytime and nighttime planetary boundary layer (PBL) and results in an increase of 39.82 m in monthly urban-averaged PBL height. These subtle changes due to urban expansion result in decernable increases in ozone concentration. Ozone concentration increases mainly in Foshan, Dongguan and south Guangzhou (around 1.5 ppbv), and the increase is larger in daytime than that of nighttime. Monthly ozone concentrations increased by 0.89 ppbv for the whole urban areas in PRD, and the areas of ozone concentration increase coincide with areas of meteorological parameters variation. At 14:00 LST, total ozone concentrations within the mixed layer in urban areas increased 80ppbv. The ozone-concentration change is mostly sensitive to changes in temperature, followed by those in PBL height and wind speed, and least to changes in the relative humidity. During the daytime (08:00-18:00 local time) the ozone concentrations increase is a U-type, in which the fewest increase is 0.2 ppbv at 14:00 LST, while at nighttime the ozone concentration increase is a V-type, and the largest increase is at 20:00 LST (more than 1.5ppbv).%利用新一代大气化学在线耦合模式WRF-Chem研究城市扩张对珠三角地区春季气象条件的改变及其对地面O3浓度的影响.研究结果表

  9. 用UV/H2O2,UV/O3,UV/H2O2/O3催化处理城市固体垃圾填埋渗出物%UV-Catalytic Treatment of Municipal Solid-Waste Landfill Leachate with Hydrogen Peroxide and Ozone Oxidation


    The performance of UV/H2O2, UV/O3, and UV/H2O2/O3 oxidation systems for the treatment of municipal solid-waste landfill leachate was investigated. Main objective of the experiment was to remove total organic carbon (TOC), non-biodegradable organic compounds (NBDOC) and color. In UV/H2O2 oxidation experiment,with the increase of H2O2 dosage, removal efficiencies of TOC and color along with the ratio of biochemical oxygen demand (BOD) to chemical oxygen demand (COD) of the effluent were increased and a better performance was obtained than the system H2O2 alone. In UV/H2O2 oxidation, under the optimum condition H2O2 (0.2 time),removal efficiencies of TOC and color were 78.9% and 95.5%, respectively, and BOD/COD ratio was significantly increased from 0.112 to 0.366. In UV/O3 oxidation, with the increase of O3 dosage, removal efficiencies of TOC and color along with BOD/COD ratio of the effluent were increased and a better performance was obtained than the system O3 alone. Under the optimum condition UV/O3 (50 mg.min-1), removal efficiencies of TOC and color were 61.0% and 87.2%, respectively, and BOD/COD ratio was significantly increased from 0.112 to 0.323. In UV/H2O2/O3 system, color removal and BOD/COD ratio were improved further and TOC removal efficiency was found to be 30.4% higher than the system UV/O3 without H2O2.

  10. Global crop yield reductions due to surface ozone exposure: 1. Year 2000 crop production losses and economic damage

    Avnery, Shiri; Mauzerall, Denise L.; Liu, Junfeng; Horowitz, Larry W.


    Exposure to elevated concentrations of surface ozone (O 3) causes substantial reductions in the agricultural yields of many crops. As emissions of O 3 precursors rise in many parts of the world over the next few decades, yield reductions from O 3 exposure appear likely to increase the challenges of feeding a global population projected to grow from 6 to 9 billion between 2000 and 2050. This study estimates year 2000 global yield reductions of three key staple crops (soybean, maize, and wheat) due to surface ozone exposure using hourly O 3 concentrations simulated by the Model for Ozone and Related Chemical Tracers version 2.4 (MOZART-2). We calculate crop losses according to two metrics of ozone exposure - seasonal daytime (08:00-19:59) mean O 3 (M12) and accumulated O 3 above a threshold of 40 ppbv (AOT40) - and predict crop yield losses using crop-specific O 3 concentration:response functions established by field studies. Our results indicate that year 2000 O 3-induced global yield reductions ranged, depending on the metric used, from 8.5-14% for soybean, 3.9-15% for wheat, and 2.2-5.5% for maize. Global crop production losses totaled 79-121 million metric tons, worth $11-18 billion annually (USD 2000). Our calculated yield reductions agree well with previous estimates, providing further evidence that yields of major crops across the globe are already being substantially reduced by exposure to surface ozone - a risk that will grow unless O 3-precursor emissions are curbed in the future or crop cultivars are developed and utilized that are resistant to O 3.

  11. Catalytic Ozonation on Cobolt /Aluminum Oxide(Co /Al2O3)for the Degradation of Trace N-Nitrosodimethylamine(NDMA)Micropullutants in Aqueous Solution%在钴/氧化铝(Co/Al2O3)上臭氧催化降解水体中痕量N-亚硝基二甲胺(NDMA)

    邹剑锋; 黎维彬; 水野忠雄


    在实验室的间歇反应器中研究了在Al2O3和Co/Al2O3催化剂上臭氧催化降解水体中N-亚硝基二甲胺(NDMA)的效果,结果表明两种催化剂的添加显著地提高了NDMA 的降解效率.主要试验参数的研究表明:Co/Al2O3的投加量、臭氧的投加量、温度等试验参数对于降解率有很大影响;当单位体积溶液中催化剂Co/Al2O3的投加量为167 mg/L、臭氧的投加量为3 mg/L时可以获得最佳的降解效果.随着温度的升高,NDMA 降解去除率逐渐升高,当反应温度由283 K升高到323 K时,在Al2O3和Co /Al2O3上NDMA 的降解效率分别由17.4 %、55.4 %提高到69.4 %、82.5 %.另外,在催化剂上添加K 元素可明显提高Co /Al2O3臭氧催化降解NDMA 的效率.

  12. Lifetimes and wave functions of ozone metastable vibrational states near the dissociation limit in full symmetry approach

    Lapierre, David; Kochanov, Roman; Kokoouline, Viatcheslav; Tyuterev, Vladimir


    Energies and lifetimes (widths) of vibrational states above the lowest dissociation limit of $^{16}$O$_3$ were determined using a previously-developed efficient approach, which combines hyperspherical coordinates and a complex absorbing potential. The calculations are based on a recently-computed potential energy surface of ozone determined with a spectroscopic accuracy [J. Chem. Phys. {\\bf 139}, 134307 (2013)]. The effect of permutational symmetry on rovibrational dynamics and the density of resonance states in O$_3$ is discussed in detail. Correspondence between quantum numbers appropriate for short- and long-range parts of wave functions of the rovibrational continuum is established. It is shown, by symmetry arguments, that the allowed purely vibrational ($J=0$) levels of $^{16}$O$_3$ and $^{18}$O$_3$, both made of bosons with zero nuclear spin, cannot dissociate on the ground state potential energy surface. Energies and wave functions of bound states of the ozone isotopologue $^{16}$O$_3$ with rotational ...

  13. Research progress of Al2O3 in catalytic ozonation for degradation of organic compounds in aqueous solution%Al2O3催化臭氧化去除水中有机物的研发进展

    王丽波; 孙志忠



  14. O3预处理耦合微生物降解修复PAHs污染土壤%Combined Ozone Pretreatment and Biodegradation for Remediation of PAHs-Contaminated Soil

    蔡月华; 张丹; 姜林; 钟茂生; 夏天翔; 姚珏君; 彭超


    通过室内批次试验,研究了O3预处理耦合微生物降解技术对北京某焦化厂PAHs(多环芳烃)污染土壤的修复效果.结果表明:在ρ(O3)为0.79、1.74、4.50 mg/L时,5 min内土壤PAHs迅速降解,去除率分别为11.01%、32.48%、34.65%,但随着降解时问的延长,土壤中PAHs降解逐渐放缓,60 min后土壤PAHs去除率分别为39.58%、52.84%、53.79%,土壤微生物菌落数量由原土的3.07×108 CFU/g分别降至1.73×106 、1.02×1O5 、1.49×103 CFU/g.经ρ(O3)为1.74 mg/L预处理5、10 min,添加LB培养基分别耦合1周微生物降解后,土壤PAHs去除率达68.93%、63.32%,相比单一微生物降解分别提高35.34%、24.33%.经ρ(O3)为1.74 mg/L预处理5 min,同时添加皂角苷及LB培养基优化降解4周后,土壤PAHs去除率为93.26%,相比仅添加LB培养基优化培养4周提高了7.00%.研究发现,O3预处理耦合微生物降解技术中ρ(O3)最佳值为1.74 mg/L、最佳预处理时间为5 min,并且O3预处理耦合微生物降解技术降解土壤中PAHs的效率优于单一O3化处理或微生物降解处理.

  15. Responses of Ilex integra Thunb. Seedlings to Elevated Air Ozone Concentration%全缘冬青幼苗(Ilex integra Thunb.)对大气O_3浓度升高的响应

    张巍巍; 牛俊峰; 冯兆忠; 王效科; 田媛; 姚芳芳


    采用开顶式气室(open top chambers,OTCs)装置,研究O3浓度升高(E-O3,约150μL.L-1)对常绿阔叶树种全缘冬青幼苗的影响,主要包括伤害症状、植株生长、光合色素含量、气体交换速率与叶绿素荧光、丙二醛含量以及主要抗氧化剂含量变化.经过高浓度O3处理一个生长季后,当年生全展叶片表面分布着大量的黑褐色斑点与斑块,呈腐蚀状凹陷于叶片表面.O3引起茎百分比显著降低7%,但对株高与基径生长、生物量累积与比叶重无显著性影响;与CF处理相比,O3处理下全缘冬青幼苗当年生全展叶片净光合速率、叶绿%One-year-old Ilex integra seedlings were exposed to charcoal-filtered(CF) and elevated ozone(E-O3,~150 μL·L-1) for 84 days in six open-top chambers.Visible injury,growth parameters,pigments content,gas exchange,chlorophyll a fluorescence and antioxidant system were investigated during the growing season.At the end of experiment,foliage showed remarkable visible symptoms with dark-brown necrotic spots and patches which were concaved on the upper surface of the current-year leaves.Although relative height and diameter increment,total biomass and specific leaf weight(SLW) remained unaffected,E-O3 significantly decreased the percentage of stem biomass in total biomass.E-O3 induced significant decrease in net photosynthetic rate,chlorophyll a/b ratio and total phenolic compound content by 19%,9% and 36%,respectively.However,stomatal conductance,intercellular CO2 concentration,chlorophyll a fluorescence parameters,pigment contents,MDA contents,total antioxidant capacity and total ascorbate content remained unaffected by E-O3.The results suggested that E-O3-induced change in components of chlorophyll contributed to the reduction of photosynthesis in Ilex integra seedlings.In addition,although visible symptom was found during the experiment,antioxidant system,most of the physiological parameters and growth were not

  16. A theoretical model of atmospheric ozone depletion

    Midya, S. K.; Jana, P. K.; Lahiri, T.


    A critical study on different ozone depletion and formation processes has been made and following important results are obtained: (i) From analysis it is shown that O3 concentration will decrease very minutely with time for normal atmosphere when [O], [O2] and UV-radiation remain constant. (ii) An empirical equation is established theoretically between the variation of ozone concentration and time. (iii) Special ozone depletion processes are responsible for the dramatic decrease of O3-concentration at Antarctica.

  17. Atmospheric pressure atomic layer deposition of Al₂O₃ using trimethyl aluminum and ozone.

    Mousa, Moataz Bellah M; Oldham, Christopher J; Parsons, Gregory N


    High throughput spatial atomic layer deposition (ALD) often uses higher reactor pressure than typical batch processes, but the specific effects of pressure on species transport and reaction rates are not fully understood. For aluminum oxide (Al2O3) ALD, water or ozone can be used as oxygen sources, but how reaction pressure influences deposition using ozone has not previously been reported. This work describes the effect of deposition pressure, between ∼2 and 760 Torr, on ALD Al2O3 using TMA and ozone. Similar to reports for pressure dependence during TMA/water ALD, surface reaction saturation studies show self-limiting growth at low and high pressure across a reasonable temperature range. Higher pressure tends to increase the growth per cycle, especially at lower gas velocities and temperatures. However, growth saturation at high pressure requires longer O3 dose times per cycle. Results are consistent with a model of ozone decomposition kinetics versus pressure and temperature. Quartz crystal microbalance (QCM) results confirm the trends in growth rate and indicate that the surface reaction mechanisms for Al2O3 growth using ozone are similar under low and high total pressure, including expected trends in the reaction mechanism at different temperatures.


    R. Rajeswari ، S. Kanmani


    Full Text Available The degradation of pesticide Carbendazim was investigated by combination of TiO2-based photocatalysis and ozonation. A batch annular photoreactor has been used for carrying out the combined process and the influence of TiO2 concentration, ozone dose and pH were investigated. The results showed that the removal rate increased with increase in ozone dosage upto 0.48 g/h and decreased above 1g/L of TiO2. At optimum pH=6, with 1g/L TiO2 and with 0.48g/h ozone dose, 88% COD removal was achieved in 3 hours by the combined photocatalytic ozonation process, where as 54% and 67% COD removal was observed with each photocatalysis and ozonation process, respectively. BOD5/COD ratio was enhanced to 0.38 and TOC removal was 80% in 180 min of combined treatment. Carbendazim was quickly degraded by the combined photocatalytic ozonation process and followed pseudo-first order kinetics. The kinetic study showed that degradation rate constant of Carbendazim with TiO2/UV/O3 to be 1.5 times higher than that & O3 with the same ozone dose and 2.2 times higher than that of TiO2/UV. A mechanism involving the formation of an ozonide radical previous to the generation of hydroxyl radicals is suggested to explain the synergistic effect between ozone and TiO2 under illumination. The laboratory study has also demonstrated that a combination of TiO2-based photocatalysis and ozonation will overcome the disadvantage of the selectivity of ozonation and the lower efficiency of TiO2 photocatalysis.

  19. Effects of climate change, CO2 and O3 on wheat productivity in Eastern China, singly and in combination

    Tao, Fulu; Feng, Zhaozhong; Tang, Haoye; Chen, Yi; Kobayashi, Kazuhiko


    Air pollution and climate change are increasing threats to agricultural production and food security. Extensive studies have focused on the effect of climate change, but the interactive effects of multiple global change factors are poorly understood. Here, we incorporate the interactions between climate change, carbon dioxide (CO2) and ozone (O3) into an eco-physiological mechanistic model based on three years of O3 Free-Air Concentration Elevation (O3-FACE) experiments. We then investigate the effects of climate change, elevated CO2 concentration ([CO2]) and rising O3 concentration ([O3]) on wheat growth and productivity in eastern China in 1996-2005 (2000s) and 2016-2025 (2020s) under two climate change scenarios, singly and in combination. We find the interactive effects of climate change, CO2 and O3 on wheat productivity have spatially explicit patterns; the effect of climate change dominates the general pattern, which is however subject to the large uncertainties of climate change scenarios. Wheat productivity is estimated to increase by 2.8-9.0% due to elevated [CO2] however decline by 2.8-11.7% due to rising [O3] in the 2020s, relative to the 2000s. The combined effects of CO2 and O3 are less than that of O3 only, on average by 4.6-5.2%, however with O3 damage outweighing CO2 benefit in most of the region. This study demonstrates a more biologically meaningful and appropriate approach for assessing the interactive effects of climate change, CO2 and O3 on crop growth and productivity. Our findings promote the understanding on the interactive effects of multiple global change factors across contrasting climate conditions, cast doubt on the potential of CO2 fertilization effect in offsetting possible negative effect of climate change on crop productivity as suggested by many previous studies.

  20. Advanced treatment of benzothiazole contaminated waters: comparison of O3, AC, and O3/AC processes.

    Valdés, H; Zaror, C A


    Benzothiazole (BT) is a toxic and poorly biodegradable contaminant, usually found in wastewater from rubber related applications. This compound could be effectively eliminated using advanced treatment processes. This paper compares experimental results on detoxification systems based on ozone oxidation, activated carbon adsorption, and simultaneous adsorption-oxidation using ozone in the presence of activated carbon. The effect of pH (2-11), and the presence of radical scavengers (tert-butyl alcohol and sodium carbonate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with activated carbon adsorption increases the overall BT oxidation rate with respect to the ozonation process and activated carbon adsorption. In the presence of free radical scavenger, only a 44% reduction in BT removal rate is observed in the simultaneous treatment, as compared with 72% when ozonation treatment is used, suggesting that BT oxidation reactions mainly take place on the activated carbon surface.

  1. Advances in understanding ozone impact on forest trees: messages from novel phytotron and free-air fumigation studies.

    Matyssek, R; Karnosky, D F; Wieser, G; Percy, K; Oksanen, E; Grams, T E E; Kubiske, M; Hanke, D; Pretzsch, H


    Recent evidence from novel phytotron and free-air ozone (O3) fumigation experiments in Europe and America on forest tree species is highlighted in relation to previous chamber studies. Differences in O3 sensitivity between pioneer and climax species are examined and viewed for trees growing at the harsh alpine timberline ecotone. As O3 apparently counteracts positive effects of elevated CO2 and mitigates productivity increases, response is governed by genotype, competitors, and ontogeny rather than species per se. Complexity in O3 responsiveness increased under the influence of pathogens and herbivores. The new evidence does not conflict in principle with previous findings that, however, pointed to a low ecological significance. This new knowledge on trees' O3 responsiveness beyond the juvenile stage in plantations and forests nevertheless implies limited predictability due to complexity in biotic and abiotic interactions. Unravelling underlying mechanisms is mandatory for assessing O3 risks as an important component of climate change scenarios.

  2. 21 CFR 184.1563 - Ozone.


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ozone. 184.1563 Section 184.1563 Food and Drugs... Substances Affirmed as GRAS § 184.1563 Ozone. (a) Ozone (O3, CAS Reg. No. 10028-15-6) is an unstable blue gas... manufacturing practice results in a maximum residual level at the time of bottling of 0.4 milligram of ozone...

  3. Seasonal association between ambient ozone and mortality in Zhengzhou, China

    Qin, Lijie; Gu, Jianqin; Liang, Shijie; Fang, Fang; Bai, Weimin; Liu, Xu; Zhao, Tao; Walline, Joseph; Zhang, Shenglong; Cui, Yingjie; Xu, Yaxin; Lin, Hualiang


    Different seasonal health effects of ambient ozone (O3) have been reported in previous studies. This might be due to inappropriate adjustment of temperature in different seasons. We used daily data on non-accidental mortality and ambient air pollution in Zhengzhou from January 19, 2013 to June 30, 2015. Season-stratified analyses using generalized additive models were conducted to evaluate the seasonal associations with adjustment of temperature with different lagged days (lag0-1 for warm season, lag0-14 for cold season). We recorded a total of 70,443 non-accidental deaths in Zhengzhou during the study period. Significant associations were observed between ambient O3 and mortality in cold season. Every 10-μg/m3 increment of 24-h O3 of 1-day lagged time was associated with a 1.38% (95% CI 0.60, 2.16%) increase in all cause mortality, 1.35% (95% CI 0.41, 2.30%) increase in cardiovascular mortality, and 1.78% (95% CI 0.43, 3.14%) increase in respiratory mortality. Similar associations were observed when using daily 1- and 8-h maximum concentrations of O3. No significant association was found during warm season. This study suggests a more pronounced ozone-mortality association in cold season in Zhengzhou, and we suggest that different lagged temperatures should be considered when examining the seasonal health effects of ambient ozone.

  4. Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3

    Kitao, Mitsutoshi; Yasuda, Yukio; Kominami, Yuji; Yamanoi, Katsumi; Komatsu, Masabumi; Miyama, Takafumi; Mizoguchi, Yasuko; Kitaoka, Satoshi; Yazaki, Kenichi; Tobita, Hiroyuki; Yoshimura, Kenichi; Koike, Takayoshi; Izuta, Takeshi


    Ground-level ozone (O3) concentrations are expected to increase over the 21st century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive Japanese beech (Fagus crenata), and in a warm temperate deciduous and evergreen forest dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations. On the basis of a practical approach for a continuous estimation of canopy-level stomatal conductance (Gs), higher phytotoxic ozone dose above a threshold of 0 uptake (POD0) with higher Gs was observed in the beech forest than that in the oak forest. Light-saturated gross primary production, as a measure of carbon sequestration capacity of forest ecosystem, declined earlier in the late growth season with increasing POD0, suggesting an earlier autumn senescence, especially in the O3-sensitive beech forest, but not in the O3-tolerant oak forest.

  5. 焦化废水尾水O3氧化消除消毒副产物生成潜能的影响分析%Treatment of coking wastewater effluent by ozonation to minimize the disinfection byproducts formation potential

    袁孟阳; 林冲; 欧桦瑟; 廖建波; 韦朝海


    Various kinds of dissolved organic matter (DOM) that existed in the effluent of coking wastewater treatment plants could become the precursors of disinfection byproducts (DBPs) during chlorination in the downstream drinking water treatment plants,posing a significant threat to water supply.Here,the potential of DBPs formation from coking wastewater effluent was investigated.The concentrations of haloacetonitriles (HANs) and trihalomethanes (THMs),two representative disinfection byproducts formed either from untreated or ozonization-treated effluents of a real coking wastewater treatment plant were analyzed using gas chromatography (GC).The analyses of molecular weight (MW) distribution and 3D-excitationemission-matrix (3DEEM) spectrum were conducted to understand the transfer mechanism of the precursors during ozonization.The results of GC showed that THMs and HANs formed from untreated effluent had concentrations in the ranges of 1950.5 ~ 3965.1 μg· L-1 and 1498.2 ~ 2571.2 μg· L-1,respectively,indicating that the effluent of industrial wastewater treatment plant could be the precursors of DBPs.In contrast,ozonation significantly reduced the amount of precursors of DBPs in coking wastewater effluent.Furthermore,it was found that higher concentration of O3 resulted in lower amounts of precursors.The results of DOC,UV254 and SUVA showed that O3 preferentially decomposed DOM that had unsaturated and aromatic components.The results of MW and 3DEEM showed that small MW (< 1 kDa) DOM was more easily degraded by O3 as compared to large MW (> 1kDa) DOM.All the results provided evidence that treatment of coking wastewater effluent by ozonation was effective in minimizing the disinfection byproducts formation potential (DBPFP).%焦化废水经生化处理后的尾水中含有多种溶解性有机物(DOM),可能成为消毒副产物的前体物,进而影响受纳水体下游给水厂的水质安全.因此,对焦化废水外排水(尾水)的消

  6. Experimental Studies on Preozonation -BAC Process and Ozonation -BAC Process in the System of Taste and Odor Drinking Water Treatment%预O3-BAC与O3-BAC工艺处理含嗅味水的试验研究

    王代平; 胡海修; 康伟



  7. Constraining ozone-precursor responsiveness using ambient measurements

    This study develops probabilistic estimates of ozone (O3) sensitivities to precursoremissions by incorporating uncertainties in photochemical modeling and evaluating modelperformance based on ground-level observations of O3 and oxides of nitrogen (NOx).Uncertainties in model form...

  8. Global ozone–CO correlations from OMI and AIRS: constraints on tropospheric ozone sources

    P. S. Kim


    Full Text Available We present a global data set of free tropospheric ozone–CO correlations with 2° × 2.5° spatial resolution from the Ozone Monitoring Instrument (OMI and Atmospheric Infrared Sounder (AIRS satellite instruments for each season of 2008. OMI and AIRS have near-daily global coverage of ozone and CO respectively and observe coincident scenes with similar vertical sensitivities. The resulting ozone–CO correlations are highly statistically significant (positive or negative in most regions of the world, and are less noisy than previous satellite-based studies that used sparser data. Comparison with ozone–CO correlations and regression slopes (dO3/dCO from MOZAIC (Measurements of OZone, water vapour, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft aircraft profiles shows good general agreement. We interpret the observed ozone–CO correlations with the GEOS (Goddard Earth Observing System-Chem chemical transport model to infer constraints on ozone sources. Driving GEOS-Chem with different meteorological fields generally shows consistent ozone–CO correlation patterns, except in some tropical regions where the correlations are strongly sensitive to model transport error associated with deep convection. GEOS-Chem reproduces the general structure of the observed ozone–CO correlations and regression slopes, although there are some large regional discrepancies. We examine the model sensitivity of dO3/dCO to different ozone sources (combustion, biosphere, stratosphere, and lightning NOx by correlating the ozone change from that source to CO from the standard simulation. The model reproduces the observed positive dO3/dCO in the extratropical Northern Hemisphere in spring–summer, driven by combustion sources. Stratospheric influence there is also associated with a positive dO3/dCO because of the interweaving of stratospheric downwelling with continental outflow. The well-known ozone maximum over the tropical South Atlantic is

  9. Influence of corona discharge on the ozone budget in the tropical free troposphere: a case study of deep convection during GABRIEL

    Bozem, H.; Fischer, H.; Gurk, C.; Schiller, C. L.; Parchatka, U.; Koenigstedt, R.; Stickler, A.; Martinez, M.; Harder, H.; Kubistin, D.; Williams, J.; Eerdekens, G.; Lelieveld, J.


    Convective redistribution of ozone and its precursors between the boundary layer (BL) and the free troposphere (FT) influences photochemistry, in particular in the middle and upper troposphere (UT). We present a case study of convective transport during the GABRIEL campaign over the tropical rain forest in Suriname in October 2005. During one measurement flight the inflow and outflow regions of a cumulonimbus cloud (Cb) have been characterized. We identified a distinct layer between 9 and 11 km altitude with enhanced mixing ratios of CO, O3, HOx, acetone and acetonitrile. The elevated O3 contradicts the expectation that convective transport brings low-ozone air from the boundary layer to the outflow region. Entrainment of ozone-rich air is estimated to account for 62% (range: 33-91%) of the observed O3. Ozone is enhanced by only 5-6% by photochemical production in the outflow due to enhanced NO from lightning, based on model calculations using observations including the first reported HOx measurements over the tropical rainforest. The "excess" ozone in the outflow is most probably due to direct production by corona discharge associated with lightning. We deduce a production rate of 5.12 × 1028 molecules O3 flash-1 (range: 9.89 × 1026-9.82 × 1028 molecules O3 flash-1), which is at the upper limit of the range reported previously.

  10. Effects of Elevated Ozone on Antioxidant System of Winter Wheat Leaf in Varied Growth Stages%O3浓度升高对不同生长期冬小麦叶片抗氧化系统的影响

    隋立华; 黄益宗; 王玮; 耿春梅; 殷宝辉


    由于人口的快速增长,人类活动导致近地层O3浓度不断提高,O3浓度升高将对植物、动物和人体健康产生极大的危害.采用开顶式气室(OTC)原位实验方法,研究O3浓度升高对不同生长期冬小麦叶片抗氧化系统的影响,进而分析O3对植物的伤害机制.结果表明,O3浓度升高可导致冬小麦拔节期和抽穗期叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,以及还原型谷胱甘肽(GSH)、抗坏血酸(AsA)、丙二醛(MDA)和可溶性蛋白含量产生变化且呈现不同的变化规律.当O3浓度为120 nL·L-1时,与对照相比,冬小麦拔节期叶片SOD、CAT和APX活性分别降低50.3%、64.9%和75.5%,POD和GR活性分别提高45.1%和80.5%,MDA、AsA和GSH含量分别提高314.3%、8.4%和31.7%,可溶性蛋白含量降低47.5%.冬小麦体内抗氧化系统物质因其所处生长季节的不同以及O3浓度的不同而不同.本研究结果显示,冬小麦在O3的污染胁迫下,为了清除体内活性氧自由基的伤害,其抗氧化系统发生了极为复杂的变化,是植物自我调节的一种反应.%As human population increases rapidly, human activities cause the increase of tropospheric ozone (O3) which significantly exerts adverse effects on the health of plants, animals and human beings. In this paper, open top chambers (OTCs) under field conditions were used to investigate the antioxidant system (malondialdehyde, MDA; solu ble protein; ascorbic acid, AsA; ghitathione, GSH, superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascor-bate peroxidase, APX; ghitathione reductase, GR) of winter wheat leaf in different growing stages under elevated O3 The results indicated that the increase of O3 significantly affected the antioxidant system of winter wheat leaf both in jointing stage and heading stage. In the level of 120 nL- L-1, as compared with the control

  11. Abiotic formation of O2 and O3 in high-CO2 terrestrial atmospheres

    Segura, A; Kasting, J F; Crisp, D; Cohen, M


    Previous research has indicated that high amounts of ozone (O3) and oxygen (O2) may be produced abiotically in atmospheres with high concentrations of CO2. The abiotic production of these two gases, which are also characteristic of photosynthetic life processes, could pose a potential "false-positive" for remote-sensing detection of life on planets around other stars.We show here that such false positives are unlikely on any planet that possesses abundant liquid water, as rainout of oxidized species onto a reduced planetary surface should ensure that atmospheric H2 concentrations remain relatively high, and that O2 and O3 remain low. Our aim is to determine the amount of O3 and O2 formed in a high CO2 atmosphere for a habitable planet without life. We use a photochemical model that considers hydrogen (H2) escape and a detailed hydrogen balance to calculate the O2 and O3 formed on planets with 0.2 of CO2 around the Sun, and 0.02, 0.2 and 2 bars of CO2 around a young Sun-like star with higher UV radiation. The ...

  12. Seasonal and diurnal variation of NOx-O3 in the troposphere of São Paulo State (Brazil)

    Dias, C. D.; Cardoso, A. A.


    Nitrogen oxides (NOx) are emitted to the atmosphere mainly as a result of combustion and play an important role on the photochemical production and destruction of ozone (O3). Tropospheric O3 is recognized as one of most critical secondary pollutants due to its oxidant potential and phytotoxicity. Besides the concentrations of its precursors, some physical factors, such as temperature, solar radiation, humidity and wind conditions may affect its formation kinetics. In São Paulo State rural area, the major source of NOx to the atmosphere is the biomass burning in the sugar cane pre-harvest, which occurs during the dry season, between May and November. The influence of this NOx source upon the formation of O3 was evaluated in this present study in the period between June 2004 and May 2005. The NO and NO2 were collected in C-18 cartridge impregnated with triethanolamine. NO was previously oxidized to NO2 by CrO3. The Griess-Saltzman reaction was used to determination of NOx. The O3 was sampled in cellulose filters impregnated with indigo blue solution. Concentrations of NOx were higher at night and during the winter, when biomass burning in the sugar cane fields happen. The maximum values reached 118.4 ppbv for NO2 and 83.3 ppbv for NO. The NO2 concentration decrease during the night and a minimum value is observed at the middle of the next day, when the O3 levels reached a maximum. The NO concentrations out of the period of biomass burn (between December and April) were close to the method detection limit, suggesting that the sugar cane burning is the major source of NO in the troposphere at this site. The results still showed that there are two maximum seasonal periods of ozone, which can be related, first, to the higher radiation intensity (summertime), and second, to the greater spread of precursors in the atmosphere, even with a minimum of insulation (wintertime). In summer, the ozone mean values are lower than those in winter. In the winter the O3 peaks may be

  13. A Lagrangian view of ozone production tendency in North American outflow in summers 2009 and 2010

    B. Zhang


    Full Text Available The Pico Mountain Observatory, located at 2225 m a.s.l. in the Azores Islands, was established in 2001 to observe long-range transport from North America to the central North Atlantic. In previous research conducted at the Observatory, ozone enhancement (>55 ppbv in North American outflows was observed, and efficient ozone production in these outflows was postulated. This study is focused on determining the causes for high d[O3]/d[CO] values (~1 ppbv ppbv−1 observed in summers of 2009 and 2010. The folded retroplume technique, developed by Owen and Honrath (2009, was applied to combine upwind FLEXPART transport pathways with GEOS-Chem chemical fields. This folded result provides a semi-Lagrangian view of polluted North American outflow in terms of physical properties and chemical processes, including production/loss rate of ozone and NOx produced by lightning and thermal decomposition of PAN. Two transport events from North America were identified for detailed analysis. High d[O3]/d[CO] was observed in both events, but due to differing transport mechanisms, ozone production tendency differed between the two. A layer of net ozone production was found at 2 km a.s.l. over the Azores in the first event plume, apparently driven by PAN decomposition during subsidence of air mass in the Azores-Bermuda High. In the second event, net ozone loss occurred during transport in the lower free troposphere, yet observed d[O3]/d[CO] was high. We estimate that in both events, CO loss through oxidation contributed significantly to d[O3]/d[CO] enhancement. Thus, CO is not appropriately used as a passive tracer of pollution in these events. In general, use of d[O3]/d[CO] as an indicator of net ozone production/loss may be invalid for any situation in which oxidants are elevated. Based on our analysis, use of d[O3]/d[CO] to diagnose ozone enhancement without verifying the assumption of negligible CO loss is not advisable.

  14. Global ozone–CO correlations from OMI and AIRS: constraints on tropospheric ozone sources

    P. S. Kim


    Full Text Available We present a global data set of free tropospheric ozone–CO correlations with 2° × 2.5° spatial resolution from the Ozone Monitoring Instrument (OMI and Atmospheric Infrared Sounder (AIRS satellite instruments for each season of 2008. OMI and AIRS have near daily global coverage of ozone and CO respectively and observe coincident scenes with similar vertical sensitivities. The resulting ozone–CO correlations are highly statistically significant (positive or negative in most regions of the world, and are less noisy than previous satellite-based studies that used sparser data. We interpret the observed ozone–CO correlations with the GEOS-Chem chemical transport model to infer constraints on ozone sources. Driving GEOS-Chem with different meteorological fields generally shows consistent ozone–CO correlation patterns, except in some tropical regions where the correlations are strongly sensitive to model transport error associated with deep convection. GEOS-Chem reproduces the general structure of the observed ozone–CO correlations and regression slopes (dO3/dCO, although there are some large regional discrepancies. We examine the model sensitivity of dO3/dCO to different ozone sources (combustion, biosphere, stratosphere, and lightning NOx by correlating the ozone change from that source to CO from the standard simulation. The model reproduces the observed positive dO3/dCO in the extratropical Northern Hemisphere in spring–summer, driven by combustion sources. Stratospheric influence there is also associated with a positive dO3/dCO because of the interweaving of stratospheric downwelling with continental outflow. The well-known ozone maximum over the tropical South Atlantic is associated with negative dO3/dCO in the observations; this feature is reproduced in GEOS-Chem and supports a dominant contribution from lightning to the ozone maximum. A~major model discrepancy is found over the Northeast Pacific in summer-fall where dO3/dCO is

  15. Elevated CO2 or O3 effects on fine-root survivorship in ponderosa pine

    Atmospheric carbon dioxide (CO2) and ozone (O3) concentrations are rising, which may have opposing effects on tree C balance and allocation to fine roots. More information is needed on interactive CO2 and O3 effects on roots, particularly fine-root life span, a critical demograp...


    Atmospheric carbon dioxide (CO2) and ozone (O3) concentrations are rising, which may have opposing effects on tree C balance and allocation to fine roots. More information is needed on interactive CO2 and O3 effects on roots, particularly fine-root life span, a critical demograph...

  17. Photolysis of pure solid O3 and O2 films at 193 nm

    Raut, U; Famá, M; Baragiola, R A


    We studied quantitatively the photochemistry of solid O3 and O2 films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O3, but a small amount of ozone remained in the film at high fluence. Photolysis of pure O2 produced O3 in an amount that increased with photon fluence to a stationary level. For both O2 and O3 films, the O3:O2 ratio at saturation is 0.03, nearly 10-30 times larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O2 due to photoabsorption by O2 dimers, a process significant at solid state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, {\\Phi} (O3) = 0.18 and for destruction of ozone and oxygen in their parent solids, {\\Phi} (- O3) = 1.7 and {\\Phi} (-O2) = 0.28. Combined with known photoabsorption cross sections, we estimate probabilities for germinate recombination of 0.15 for O3 fragments and 0.90 for oxygen atoms from O2 dissociation. Using ...

  18. Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere

    Wennberg, P. O.; Hanisco, T. F.; Jaegle, L.; Jacob, D. J.; Hintsa, E. J.; Lanzendorf, E. J.; Anderson, J. G.; Gao, R.-S.; Keim, E. R.; Donnelly, S. G.; DelNegro, L. A.; Fahey, D. W.; McKeen, S. A.; Salawitch, R. J.; Webster, C. R.; May, R. D.; Herman, R. L.; Proffitt, M. H.; Margitan, J. J.; Atlas, E. L.


    The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3, in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HO(x) required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of 03 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day.This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more 03 than expected.

  19. Ozone Applications in Food Industry

    Elif Savaş


    Full Text Available Known as active oxygen Ozone (O3, are among the most effective antimicrobials. The sun's ultraviolet rays and ozone caused by electric arcs of lightning occurring instantly around the world, and is available as a protective shield protects the animals against the effects of the sun's radiation. In the food industry, directly or indirectly in contact with food during processing of foods and chemical treatment of water disinfection bacteriological emerges as an alternative protection method. In this study, the effects of the ozone applications will evaluated as an alternative to conventional disinfectants in food industry.

  20. Frustration of Negative Capacitance in Al2O3/BaTiO3 Bilayer Structure

    Kim, Yu Jin; Park, Min Hyuk; Lee, Young Hwan; Kim, Han Joon; Jeon, Woojin; Moon, Taehwan; Do Kim, Keum; Jeong, Doo Seok; Yamada, Hiroyuki; Hwang, Cheol Seong


    Enhancement of capacitance by negative capacitance (NC) effect in a dielectric/ferroelectric (DE/FE) stacked film is gaining a greater interest. While the previous theory on NC effect was based on the Landau-Ginzburg-Devonshire theory, this work adopted a modified formalism to incorporate the depolarization effect to describe the energy of the general DE/FE system. The model predicted that the SrTiO3/BaTiO3 system will show a capacitance boost effect. It was also predicted that the 5 nm-thick Al2O3/150 nm-thick BaTiO3 system shows the capacitance boost effect with no FE-like hysteresis behavior, which was inconsistent with the experimental results; the amorphous-Al2O3/epitaxial-BaTiO3 system showed a typical FE-like hysteresis loop in the polarization – voltage test. This was due to the involvement of the trapped charges at the DE/FE interface, originating from the very high field across the thin Al2O3 layer when the BaTiO3 layer played a role as the NC layer. Therefore, the NC effect in the Al2O3/BaTiO3 system was frustrated by the involvement of reversible interface charge; the highly stored charge by the NC effect of the BaTiO3 during the charging period could not be retrieved during the discharging process because integral part of the polarization charge was retained within the system as a remanent polarization.

  1. Degradation of organic matter from wastewater using advanced primary treatment by O3 and O3/UV in a pilot plant

    Bustos-Terrones, Yaneth; Rangel-Peraza, Jesús Gabriel; Sanhouse, Antonio; Bandala, Erick R.; Torres, Luis G.


    The oxidation of organic matter from wastewater using ozone, ultraviolet radiation and ozone/UV oxidation was evaluated in a pilot plant, applying a continuous effluent arising from the Autonomous Metropolitan University wastewater treatment plant. The oxidation was measured as the efficiency to remove organic load, measured as chemical oxygen demand. The use of ozone and UV was evaluated separately and in combination through a continuous process. Three different ozone doses (0.6-1.2 mg O3/L) and three different UV radiation fluencies (6.7-20.12 mJ/cm2) were assessed. A synergistic effect of the combined process ozone/UV was demonstrated, and a maximal chemical oxygen demand reduction was achieved both processes. Due to residence times used (less than 1 min), 36% of chemical oxygen demand reduction was obtained when ozone treatment was evaluate separately and only 9% using ultraviolet radiation.

  2. Impact of Ozone Gradient on Grapevine Leaves

    Alebic-Juretic, Ana; Bokan-Vucelic, Itana; Mifka, Boris; Zatezalo, Marija; Zubak, Velimir


    Due to complex orography and air mass circulation, the Rijeka Bay area is characterized by O3 gradient, with concentrations risen with the altitude (1). Therefore AOT40 values were often exceeded and should result in harmful effects on vegetation. Based on previous controlled experiments (2), we examined the possible effect of atmospheric ozone on grape leaves under natural O3 gradient. Grapevine leaves (2-5) were collected from May to September 2016 at two sampling points in the proximity of two AQM stations: Site 1 in the city centre (20m asl) and Site 2 (186m asl) in the suburban settlement. Subsequent to weighing and determination of surface area, the leaves (0,5 g) were extracted in 95% ethanol and analysed on chlorophyl a (Chla), chlorophyl b (Chlb) and carotene (Car) content by UV-VIS spectrometry on 3 wavelengths (664, 649, 470 nm) (3) In summer 2016 O3 gradient was not that pronounced as usual (1), but stil the concentrations differed by approx. 20%, exceeding national AOT40 value at both sites (22.360 and 28.061 μg m-3 h, respectively, at Sites 1 and 2). The concentrations of other pollutants were bellow limit values (LV). The Cha and Chb in a sample leaves collected at the end of May at Site 2 are equal to that with filtered O3 in control experiment (2), i.e. without damage caused by ozone, while the Car content is lower approx. 50% and is kept at the same level. The con-centrations of pigments obtained in July prooved the possible damage by O3, while in subsequent months could speed up natural ageing. This is the first evidence of O3 damage on plants in the Rijeka Bay area, in spite of weaker O3 gradient and lacking visible signs of damage. Preliminary results indicate the need for more frequent sampling, particularly in the period included in AOT40 (May-July). References: 1. Alebić-Juretić A (2012) Int J Remote Sensing, 33(2): 335-345 2. Britvec M, Reichenauer T, Soja G., Ljubešić N, Pećina M (2001) Biologia (Bratislava),56/4: 417-424 3. Sumanata

  3. Study of ozone "weekend effect" in Shanghai

    TANG WenYuan; ZHAO ChunSheng; GENG FuHai; PENG Li; ZHOU GuangQiang; GAO Wei; XU JianMing; TIE XueXi


    Analysis of observed ozone data in 2006 from five monitoring sites (Xujiahui, Chongming, Baoshan, Pudong, Jinshan) in Shanghai reveals that ozone (O3) concentrations in Xujiahui are higher at weekends than those on weekdays, despite the fact that emissions of ozone precursor substances, such as oxides of nitrogen (NOX), carbon monoxide (CO) and volatile organic compounds (VOCs) are lower at weekends than those on weekdays.The possible chemical cause of ozone "weekend effect" is that NO2/NO ratio increases at weekends by 25.61% compared with those on weekdays.In addition, because of an average 12.13% reduction in NOx (NO + NO2) in the early morning (05:00-09:00) at weekends compared with that on weekdays, the ozone inhibition period ends 0.5 h earlier at weekends resulting in the longer duration of ozone accumulation and the higher ozone production rate.The rate of ozone production is a function of VOCs and NOx in the atmosphere.VOCs/NOx ratio in Xujiahui is 4.55 at weekends, and 4.37 on weekdays, belonging to the "NOx-limited".The increasing VOCs/NOx ratio at weekends leads to ozone enhancement from 73 ppbv to 80 ppbv, which are consistent with ozone "weekend effect" in Xujiahui.Furthermore, combining with MICAPS cloud amount data, the fact that ozone "weekend effect" in Xujiahui weakens gradually along with the increasing of cloud amount indicates that ozone photochemical production leads to ozone "weekend effect" in Xujiahui of Shanghai.

  4. An Uncaria tomentosa (cat's claw) extract protects mice against ozone-induced lung inflammation.

    Cisneros, Francisco J; Jayo, Manuel; Niedziela, Linda


    Ozone (O(3)) inhalation has been associated with respiratory tract inflammation and lung functional alterations. To characterize the O(3)-induced lung inflammation in mice, the effective dose and exposure time were determined. Total protein levels of bronchoalveolar lavage fluid (BALF), cytological smears, and lung histopathology and morphometry were used to assess and measure the degree of pulmonary inflammation in the mouse model. Ozone inhalation caused acute pneumonitis that was characterized by a high number of infiltrating neutrophils (PMNs) immediately after exposure and increased levels of protein in BALF in mice killed 8h after O(3) exposure. The anti-inflammatory properties of Uncaria tomentosa (UT) have been documented previously. To evaluate the anti-inflammatory effects of UT, male mice were given an UT extract for 8 days, exposed to O(3), and killed 0 or 8 h after O(3) exposure. When compared to untreated controls, UT-treated mice had significantly (p < 0.05) lower levels of protein in BALF, lower degree of epithelial necrosis, higher number of intact epithelial cell nuclei in bronchial wall, and decreased number of PMNs in the bronchiolar lumen. Therefore, UT extract appeared to prevent O(3)-induced respiratory inflammation in male mice.

  5. Diagnostic Evaluation of Ozone Production and Horizontal Transport in a Regional Photochemical Air Quality Modeling System

    A diagnostic model evaluation effort has been performed to focus on photochemical ozone formation and the horizontal transport process since they strongly impact the temporal evolution and spatial distribution of ozone (O3) within the lower troposphere. Results from th...

  6. Effects of ozone on the foliar histology of the mastic plant (Pistacia lentiscus L.).

    Reig-Armiñana, J; Calatayud, V; Cerveró, J; García-Breijo, F J; Ibars, A; Sanz, M J


    An open-top chamber study was conducted to investigate the tissue and cellular-level foliar effects of ozone (O3) on a Mediterranean evergreen species, the mastic plant (Pistacia lentiscus L.). Plants were exposed at three different O3 levels, and leaf samples were collected periodically from the beginning of the exposure. Although no visible foliar injury was evident, alterations of the plastids and vacuoles in the mesophyll were observed. Senescence processes were accelerated with an anomalous stacking of tannin vacuoles, and a reduction in the size and number of the chloroplasts. Overall, most of the modifications induced by O3 were consistent with previously reported observations on deciduous broadleaf species, with the exception of alterations in the cells covering the secretory channels, reported here as a new finding. Comments on the feasibility of using microscopy to validate O3 related field observations and subtle foliar injury are also given.

  7. Photochemical oxidation of chloride ion by ozone in acid aqueous solution.

    Levanov, Alexander V; Isaykina, Oksana Ya; Amirova, Nazrin K; Antipenko, Ewald E; Lunin, Valerii V


    The experimental investigation of chloride ion oxidation under the action of ozone and ultraviolet radiation with wavelength 254 nm in the bulk of acid aqueous solution at pH 0-2 has been performed. Processes of chloride oxidation in these conditions are the same as the chemical reactions in the system O3 - OH - Cl(-)(aq). Despite its importance in the environment and for ozone-based water treatment, this reaction system has not been previously investigated in the bulk solution. The end products are chlorate ion ClO3(-) and molecular chlorine Cl2. The ions of trivalent iron have been shown to be catalysts of Cl(-) oxidation. The dependencies of the products formation rates on the concentrations of O3 and H(+) have been studied. The chemical mechanism of Cl(-) oxidation and Cl2 emission and ClO3(-) formation has been proposed. According to the mechanism, the dominant primary process of chloride oxidation represents the complex interaction with hydroxyl radical OH with the formation of Cl2(-) anion-radical intermediate. OH radical is generated on ozone photolysis in aqueous solution. The key subsequent processes are the reactions Cl2(-) + O3 → ClO + O2 + Cl(-) and ClO + H2O2 → HOCl + HO2. Until the present time, they have not been taken into consideration on mechanistic description and modelling of Cl(-) oxidation. The final products are formed via the reactions 2ClO → Cl2O2, Cl2O2 + H2O → 2H(+) + Cl(-) + ClO3(-) and HOCl + H(+) + Cl(-) ⇄ H2O + Cl2. Some portion of chloride is oxidized directly by O3 molecule with the formation of molecular chlorine in the end.

  8. Ozone Depletion, UVB and Atmospheric Chemistry

    Stolarski, Richard S.


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

  9. Ground based infrared measurements of the global distribution of ozone in the atmosphere of Mars

    Kostiuk, Theodor; Espenak, F.; Mumma, M. J.; Zipoy, D.


    The global distribution of ozone in the atmosphere of Mars was determined from Doppler-limited infrared heterodyne spectroscopy measurements at the NASA Infrared Telescope Facility (IRTF) facility during June 3-7, 1988. Mars spectra near two O3 lines arising from the v sub 3 band near 1031.45 cm (-1) were used. The lines were Doppler shifted out of the strong terrestrial ozone absorption spectrum and its effect was removed. Ozone measurements were obtained at eight beam positions over a range of latitudes and local solar zenith angles. The beam size of the planet was 1.4 arcsec. A Martian CO2 line appeared in the spectra and was inverted to retrieve local temperature profiles. Using these temperature profiles, the total ozone column abundance at each position was retrieved by fitting the measured line with synthetic spectra generated by a radiative transfer program. The only previous measurement of ozone at this season was made above the South polar cap by Mariner 7 and revealed an abundance of 10 micron-atm. However, the retrieved O3 column abundances from this investigation are less than 2.2 micron-atm at all positions sampled. These results are consistent with mid-spring abundances predicted by photochemical models of Liu and Donahue, and Shimazaki and Shimizu.

  10. Ozonation degradation of microcystin-LR in aqueous solution: intermediates, byproducts and pathways.

    Chang, Jing; Chen, Zhong-lin; Wang, Zhe; Shen, Ji-min; Chen, Qian; Kang, Jing; Yang, Lei; Liu, Xiao-wei; Nie, Chang-xin


    The intermediates and byproducts formed during the ozonation of microcystin-LR (MC-LR, m/z = 995.5) and the probable degradation pathway were investigated at different initial molar ratios of ozone to MC-LR ([O3]0/[MC-LR]0). Seven reaction intermediates with m/z ≥ 795.4 were observed by LC/MS, and four of them (m/z = 815.4, 827.3, 853.3 and 855.3) have not been previously reported. Meanwhile, six aldehyde-based byproducts with molecular weights of 30-160 were detected for the first time. Intermediates structures demonstrated that ozone reacted with two sites of MC-LR: the diene bonds in the Adda side chain and the Mdha amino acid in the cyclic structure. The fragment from the Adda side chain oxidative cleavage could be further oxidized to an aldehyde with a molecular weight of 160 at low [O3]0/[MC-LR]0. Meanwhile, the polypeptide structure of MC-LR was difficult to be further oxidized, unless [O3]0/[MC-LR]0 > 10. After further oxidation of the intermediates, five other aldehyde-based byproducts were detected by GC/MS: formaldehyde, acetaldehyde, isovaleraldehyde, glyoxal and methylglyoxal. Formaldehyde, isovaleraldehyde and methylglyoxal were the dominant species. The yields of the aldehydes varied greatly, depending on the value of [O3]0/[MC-LR]0.

  11. Removal of 2,4-Dichlorophenoxy acetic acid from aqueous solution by a two phase ozonation system of water/ ozone- loaded organic solvent%水/载O3有机溶剂两相臭氧氧化法降解水体中2,4-二氯苯氧乙酸

    史震宇; 李时银; 陆继来; 邹敏; 张利民



  12. Effect of liquefied petroleum gas on ozone formation in Guadalajara and Mexico City.

    Jaimes-López, J Luis; Sandoval-Fernández, Julio; González-Ortíz, Emmanuel; Vázquez-García, Marcos; González-Macías, Uriel; Zambrano-García, Angel


    Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O3) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O3 was monitored in each city for 20 days (8:00 a.m.-6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). Tested additions of both components were 35% (by volume) in GMA and 60% (by volume) in MCMA. The addition effects on O3 (max) were compared with effects from diluting LPG components or total nonmethane hydrocarbons (tNMHCs) by 50%. Diluting tNMHCs had the greatest absolute effect at both cities: it lowered O3 (max) by 24% in GMA and 55% in MCMA. Adding commercial LPG increased O3 (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O3 (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O3 (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O3 formation to a lesser extent than estimated previously.

  13. The Distribution of Ozone in the Early Stages of Polar Vortex Development

    Kawa, S. R.; Newman, P. A.; Schoeberl, M. R.; Bevilacqua, R.; Bhartia, P. K. (Technical Monitor)


    Previous analysis has shown that the distribution of O3 at high northern latitudes in the lower-to-middle stratosphere at the beginning of the winter season, 1999-2000 has a characteristic distribution, which is consistent between in situ and satellite measurements [Kawa et al., The Interaction Between Dynamics and Chemistry of Ozone in the Set-up Phase of the Northern Hemisphere Polar Vortex, submitted manuscript, 2001 ]. Initial O3 profiles in the vortex are similar to each other and are quite different from outside the vortex at the same latitude and also from a zonal mean climatology. In the vortex, O3 is nearly constant from 500 to above 800 K with a value at 3 ppmv +/- approx.10%. Values outside the vortex are up to a factor of 2 higher and increase significantly with potential temperature. The seasonal time series of POAM data shows that relatively low O3 mixing ratios, which characterize the vortex in late fall, are already present at high latitudes at the end of summer in September before the vortex circulation sets up. This suggests a possible feedback role between O3 chemistry and the formation of the vortex, which is dominated by the seasonal radiation balance. Here we show that these characteristic O3 distributions are consistent from year to year and between the hemispheres. We will attempt to determine whether variations in fall vortex O3 are related in any way to O3 abundances and vortex structure later during winter and into spring.

  14. Phenomenology of high-ozone episodes in NE Spain

    Querol, Xavier; Gangoiti, Gotzon; Mantilla, Enrique; Alastuey, Andrés; Cruz Minguillón, Maria; Amato, Fulvio; Reche, Cristina; Viana, Mar; Moreno, Teresa; Karanasiou, Angeliki; Rivas, Ioar; Pérez, Noemí; Ripoll, Anna; Brines, Mariola; Ealo, Marina; Pandolfi, Marco; Lee, Hong-Ku; Eun, Hee-Ram; Park, Yong-Hee; Escudero, Miguel; Beddows, David; Harrison, Roy M.; Bertrand, Amelie; Marchand, Nicolas; Lyasota, Andrei; Codina, Bernat; Olid, Miriam; Udina, Mireia; Jiménez-Esteve, Bernat; Soler, María R.; Alonso, Lucio; Millán, Millán; Ahn, Kang-Ho


    Ground-level and vertical measurements (performed using tethered and non-tethered balloons), coupled with modelling, of ozone (O3), other gaseous pollutants (NO, NO2, CO, SO2) and aerosols were carried out in the plains (Vic Plain) and valleys of the northern region of the Barcelona metropolitan area (BMA) in July 2015, an area typically recording the highest O3 episodes in Spain. Our results suggest that these very high O3 episodes were originated by three main contributions: (i) the surface fumigation from high O3 reservoir layers located at 1500-3000 m a.g.l. (according to modelling and non-tethered balloon measurements), and originated during the previous day(s) injections of polluted air masses at high altitude; (ii) local/regional photochemical production and transport (at lower heights) from the BMA and the surrounding coastal settlements, into the inland valleys; and (iii) external (to the study area) contributions of both O3 and precursors. These processes gave rise to maximal O3 levels in the inland plains and valleys northwards from the BMA when compared to the higher mountain sites. Thus, a maximum O3 concentration was observed within the lower tropospheric layer, characterised by an upward increase of O3 and black carbon (BC) up to around 100-200 m a.g.l. (reaching up to 300 µg m-3 of O3 as a 10 s average), followed by a decrease of both pollutants at higher altitudes, where BC and O3 concentrations alternate in layers with parallel variations, probably as a consequence of the atmospheric transport from the BMA and the return flows (to the sea) of strata injected at certain heights the previous day(s). At the highest altitudes reached in this study with the tethered balloons (900-1000 m a.g.l.) during the campaign, BC and O3 were often anti-correlated or unrelated, possibly due to a prevailing regional or even hemispheric contribution of O3 at those altitudes. In the central hours of the days a homogeneous O3 distribution was evidenced for the lowest

  15. Ozone and cardiovascular injury

    Rainaldi Giuseppe


    Full Text Available Abstract Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular diseases in urban communities. The potential detrimental effects are both acute and chronic having a strong impact on morbidity and mortality. The acute exposure to pollutants has been linked to adverse cardiovascular events such as myocardial infarction, heart failure and life-threatening arrhythmias. The long-terms effects are related to the lifetime risk of death from cardiac causes. The WHO estimates that air pollution is responsible for 3 million premature deaths each year. The evidence supporting these data is very strong nonetheless, epidemiologic and observational data have the main limitation of imprecise measurements. Moreover, the lack of clinical experimental models makes it difficult to demonstrate the individual risk. The other limitation is related to the lack of a clear mechanism explaining the effects of pollution on cardiovascular mortality. In the present review we will explore the epidemiological, clinical and experimental evidence of the effects of ozone on cardiovascular diseases. The pathophysiologic consequences of air pollutant exposures have been extensively investigated in pulmonary systems, and it is clear that some of the major components of air pollution (e.g. ozone and particulate matter can initiate and exacerbate lung disease in humans 1. It is possible that pulmonary oxidant stress mediated by particulate matter and/or ozone (O3 exposure can result in downstream perturbations in the cardiovasculature, as the pulmonary and cardiovascular systems are intricately associated, and it is well documented that specific environmental toxins (such as tobacco smoke 2 introduced through the lungs can initiate and/or accelerate cardiovascular disease development. Indeed, several epidemiologic studies have proved that there is an association between PM and O3 and the increased incidence of cardiovascular morbidity

  16. Advanced treatment of port cabin washing wastewater by integrated process ozonization-biological aerated filter-biological aerated filter%一体化O3-BAF—BAF组合工艺深度处理港口洗舱废水

    葛启龙; 汪晓军


    采用一体化臭氧曝气生物滤池(O3-BAF)—曝气生物滤池(BAF)组合工艺对二级生化处理后的港口码头洗舱化学品废水进行深度处理,进水COD约为200~240 mg/L,色度为16~32倍时,经该工艺处理后出水COD<30mg/L,去除率>91%,色度降到4倍以下,出水水质达到《生活杂用水水质标准》(CJ/T48-1999)要求.工程运行实践表明,该深度处理系统运行稳定,处理效率高,具有良好的经济效益与环境效益.%The integrated ozonization-biological aerated filter-biological aerated filter combined process has been applied to the advanced treatment of port cabin washing wastewater after secondary biochemical treatment.When the COD of the influent is 200-240 mg/L,and chroma is 16-32 times,COD of effluent is reduced to less than 30 mg/L after treatment,the removing rate is more than 91%,and chroma is reduced to less than 4 times,reaching the specified Miscellaneous Domestic Water Quality Standard(CJ/T 48-1999).The result shows that the advanced treatment system runs stably,and has high treatment efficiency.It has great economic and environmental benefits.

  17. Effects of ozone and ozone/peroxide pretreatments on disinfection byproduct formation during subsequent chlorination and chloramination.

    Yang, Xin; Peng, Jinfeng; Chen, Baiyang; Guo, Wanhong; Liang, Yongmei; Liu, Wei; Liu, Lu


    Ozone (O3) and ozone/hydrogen peroxide (O3/H2O2) can be used in water treatment facilities to remove many organic micropollutants with taste, odor, and color implications. The effects of O3 and O3/H2O2 on the formation of disinfection byproducts (DBPs) in subsequent chlorination and chloramination processes, however, are not well determined. In this study, we compared the yields of a series of regulated and emerging DBPs during sequenced O3-Cl2, O3/H2O2-Cl2, O3-NH2Cl, and O3/H2O2-NH2Cl oxidation of 11 samples, each with different hydrophobicity, bromide concentration, soluble microbial products, and humic substances. For most water, pretreatment with O3 and O3/H2O2 increased the formation of chloral hydrate (CH), trichloronitromethane (TCNM) and haloketones (HKs) but lowered the yields of haloacetonitriles (HANs) during chlorination processes. Compared with O3 alone, O3/H2O2 in combination generated more CH and HKs during chlorination, and their extents of formation appeared to depend on the O3 doses. In terms of chloramination, both O3 and O3/H2O2 reduced THM, HAA, and HAN formation significantly without increasing CH, TCNM, or HKs. These results suggest that O3 or O3/H2O2 pretreatments may provide some benefits for the chloramination process in controlling regulated and emerging DBPs in waters without high bromide content.

  18. Lethal doses of ozone for control of all stages of internal and external feeders in stored products

    Hansen, Lise S.; Hansen, Peer; Jensen, Karl-Martin V.


    Gaseous ozone (O3) has potential for control of insects in stored grain. Previous studies have focused on freely exposed insects. Immatures of internal pests, (e.g. Sitophilus spp. and most stages of Rhyzopertha dominica F.) are protected within kernels and probably require higher doses and....../or longer treatment times for full control. A laboratory study determined the doses of ozone necessary for full control of freely exposed and internal stages of eleven stored product pest species. Test insects were three species of Sitophilus, R. dominica, Tribolium confusum Jacquelin du Val, T. castaneum...

  19. Halogen chemistry reduces tropospheric O3 radiative forcing

    Sherwen, Tomás; Evans, Mat J.; Carpenter, Lucy J.; Schmidt, Johan A.; Mickley, Loretta J.


    Tropospheric ozone (O3) is a global warming gas, but the lack of a firm observational record since the preindustrial period means that estimates of its radiative forcing (RFTO3) rely on model calculations. Recent observational evidence shows that halogens are pervasive in the troposphere and need to be represented in chemistry-transport models for an accurate simulation of present-day O3. Using the GEOS-Chem model we show that tropospheric halogen chemistry is likely more active in the present day than in the preindustrial. This is due to increased oceanic iodine emissions driven by increased surface O3, higher anthropogenic emissions of bromo-carbons, and an increased flux of bromine from the stratosphere. We calculate preindustrial to present-day increases in the tropospheric O3 burden of 113 Tg without halogens but only 90 Tg with, leading to a reduction in RFTO3 from 0.43 to 0.35 Wm-2. We attribute ˜ 50 % of this reduction to increased bromine flux from the stratosphere, ˜ 35 % to the ocean-atmosphere iodine feedback, and ˜ 15 % to increased tropospheric sources of anthropogenic halogens. This reduction of tropospheric O3 radiative forcing due to halogens (0.087 Wm-2) is greater than that from the radiative forcing of stratospheric O3 (˜ 0.05 Wm-2). Estimates of RFTO3 that fail to consider halogen chemistry are likely overestimates (˜ 25 %).

  20. Global health benefits of mitigating ozone pollution with methane emission controls

    West, J. Jason; Fiore, Arlene M.; Horowitz, Larry W.; Mauzerall, Denise L.


    Methane (CH4) contributes to the growing global background concentration of tropospheric ozone (O3), an air pollutant associated with premature mortality. Methane and ozone are also important greenhouse gases. Reducing methane emissions therefore decreases surface ozone everywhere while slowing climate warming, but although methane mitigation has been considered to address climate change, it has not for air quality. Here we show that global decreases in surface ozone concentrations, due to methane mitigation, result in substantial and widespread decreases in premature human mortality. Reducing global anthropogenic methane emissions by 20% beginning in 2010 would decrease the average daily maximum 8-h surface ozone by 1 part per billion by volume globally. By using epidemiologic ozone-mortality relationships, this ozone reduction is estimated to prevent 30,000 premature all-cause mortalities globally in 2030, and 370,000 between 2010 and 2030. If only cardiovascular and respiratory mortalities are considered, 17,000 global mortalities can be avoided in 2030. The marginal cost-effectiveness of this 20% methane reduction is estimated to be 420,000 per avoided mortality. If avoided mortalities are valued at 1 million each, the benefit is 240 per tonne of CH4 (12 per tonne of CO2 equivalent), which exceeds the marginal cost of the methane reduction. These estimated air pollution ancillary benefits of climate-motivated methane emission reductions are comparable with those estimated previously for CO2. Methane mitigation offers a unique opportunity to improve air quality globally and can be a cost-effective component of international ozone management, bringing multiple benefits for air quality, public health, agriculture, climate, and energy. human health | mortality | tropospheric ozone | air quality

  1. Validation of Global Ozone Monitoring Experiment zone profiles and evaluation of stratospheric transport in a global chemistry transport model

    Laat,; Landgraf, J.; Aben, I.; Hasekamp, O.; Bregman, B.


    This paper presents a validation of Global Ozone Monitoring Experiment (GOME) ozone (O3) profiles which are used to evaluate stratospheric transport in the chemistry transport model (CTM) Tracer Model version 5 (TM5) using a linearized stratospheric O3 chemistry scheme. A comparison of GOME O3 profi

  2. Air pollution effect of O3 on crop yield in rural India.

    Debaje, S B; Kakade, A D; Jeyakumar, S Johnson


    Measurement of surface ozone (O(3)) mixing ratio was made from January 2006 to December 2007 in Ahmednagar (19.1°N, 74.8°E, 657 m above sea level), India. The monthly average of daytime maximum of O(3) mixing ratio ranged from 14 to 57 parts per billion by volume (ppbv) with an annual average of about 20 ppbv. The estimated winter wheat and summer crop yield reduction by 10% and 15%, respectively from present O(3) pollution level associated with AOT40 (accumulation exposure of O(3) concentration over a threshold of 40 ppbv) index values 7370-9150 ppbv h in rural areas.

  3. Optimization and interpretation of O3 and O3/H2O2 oxidation processes to pretreat hydrocortisone pharmaceutical wastewater.

    Li, Guiju; He, Jingjing; Wang, Dandan; Meng, Panpan; Zeng, Ming


    Chemical synthetic pharmaceutical wastewater must be pretreated before traditional biological treatment to improve the biodegradability of pollutants due to their high concentration and complex composition. This study investigated O3 and O3/H2O2 systems to pretreat hydrocortisone wastewater. The optimum treatment efficiency of the O3 system was achieved under pH value of 5.76, dosage of O3 of 217.5 mg/L, and reaction time of 90 min. The removal efficiency of chemical oxygen demand (COD) and total organic carbon (TOC) was 94% and 92%, respectively. The ratio of biochemical oxygen demand (BOD) and COD (B/C) increased from 0.066 to 0.310. Moreover, the optimum H2O2/O3 molar ratio was 0.3 with the optimum pH of 3, and reaction time was reduced to 15 min to reach COD removal efficiency of 67.3% in the O3/H2O2 oxidation system. Interestingly, isobutanol was assumed to be a good hydroxyl radical trapping agent due to the great decrease of Fenton reagent reaction rate constant. By comparing two different kinetic models, oxidation mechanism could be interpreted by the pseudo first-order kinetic model with the high correlation coefficient R2 above 0.9787. It can be concluded that ozonation system was controlled by both direct oxidation and free radical oxidation, and particularly the later one played a dominant role.

  4. Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

    Marinov, Daniil; Guerra, Vasco; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine


    A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1-5 Torr and discharge currents ˜40-120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O_3^{*} , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O_3^{*} is strongly coupled with those of atomic oxygen and O2(a 1Δg) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established.

  5. Techno-economic evaluation of the application of ozone-oxidation in a full-scale aerobic digestion plant.

    Chiavola, Agostina; D'Amato, Emilio; Gori, Riccardo; Lubello, Claudio; Sirini, Piero


    This paper deals with the application of the ozone-oxidation in a full scale aerobic sludge digester. Ozonation was applied continuously to a fraction of the biological sludge extracted from the digestion unit; the ozonated sludge was then recirculated to the same digester. Three different ozone flow rates were tested (60,500 and 670g O3 h(-1)) and their effects evaluated in terms of variation of the total and soluble fractions of COD, nitrogen and phosphorous, of total and volatile suspended solids concentrations and Sludge Volume Index in the aerobic digestion unit. During the 7-month operation of the ozonation process, it was observed an appreciable improvement of the aerobic digestion efficiency (up to about 20% under the optimal conditions) and of the sludge settleability properties. These results determined an average reduction of about 60% in the biological sludge extracted from the plant and delivered to final disposal. A thorough economic analysis showed that this reduction allowed to achieve a significant cost saving for the plant with respect to the previous years operated without ozonation. Furthermore, it was determined the threshold disposal cost above which implementation of the ozone oxidation in the aerobic digestion units of similar WWTPs becomes economically convenient (about 60€t(-1) of sludge).

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

    Takahiro Nakajima

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

  7. Wintertime Distributed Ozone Measurement in Utah's Uintah Basin during UBWOS 2012

    Moore, K. D.; Martin, R. S.; Harper, K.; Lyman, S. N.


    Recent wintertime measurements in two basins in the Rocky Mountains with significant fossil fuel production have revealed serious air quality concerns with respect to ozone (O3). Wintertime O3 levels greater than the current National Ambient Air Quality Standard (NAAQS) of 75 ppbv, expressed as a daily maximum 8-hr average, were observed first in the Upper Green River Basin of western Wyoming in 2005 and then in the Uintah Basin of eastern Utah in early 2010. This abstract reports on a part of the Uintah Basin Winter Ozone 2012 Study (UBWOS 2012) designed to better understand the temporal and spatial extents of elevated O3 in the Basin. A prior study in the Basin during winter 2010/2011 investigated the temporal and spatial extent of O3. Ten monitoring sites were setup throughout the Basin using 2B Technology 205 Ozone Monitors; data from six other monitoring sites around the Basin were also gathered. Hourly averaged O3 over 120 ppbv were recorded in many locations. Levels above the 75 ppbv 8-hr NAAQS were observed at 14 of the 16 sites, with 11 sites logging more than 3 exceedences. Two sites recorded 25 exceedences. The highest O3 and greatest number of exceedences occurred in areas with the greatest fossil fuel production density. Elevated O3 was also found in population centers but with a different diurnal pattern due to local sources. The follow-on study conducted during winter 2011/2012 expanded the number of ozone monitoring sites to 30 to provide better spatial coverage; 19 were operated by the investigators and 11 were operated by other groups. In contrast to the previous study, no elevated O3 levels were recorded at any location. The highest 1-hr O3 level observed was 65.8 ppbv and the highest 8-hr average level was 62.9 ppbv. The most significant difference between the two winters was the weather - winter 2010/2011 had snow cover from December through mid-March and experienced 6+ multi-day temperature inversion periods, while winter 2011/2012 had very

  8. Hydrological controls on the tropospheric ozone greenhouse gas effect

    Kuai, Le; Bowman, Kevin W.; Worden, Helen M.; Herman, Robert L.; Susan S. Kulawik


    The influence of the hydrological cycle in the greenhouse gas (GHG) effect of tropospheric ozone (O3) is quantified in terms of the O3longwave radiative effect (LWRE), which is defined as the net reduction of top-of-atmosphere flux due to total tropospheric O3absorption. The O3LWRE derived from the infrared spectral measurements by Aura’s Tropospheric Emission Spectrometer (TES) show that the spatiotemporal variation of LWRE is relevant to relative humidity, surface temperature, and troposphe...

  9. Interactive effects of O3 exposure on California black oak (Quercus kelloggii Newb.) seedlings with and without N amendment

    T. Handley; Nancy Grulke


    We examined the short-term separate and combined effects of simulated nitrogen (N) deposition (fertilization) and ozone (O3) exposure on California black oak seedlings (Quercus kelloggii Newb.), an ecologically important tree of the San Bernardino Mountains downwind of Los Angeles. Realistic concentrations of O3...

  10. BrCl production in NaBr/NaCl/HNO3/O3 solutions representative of sea-salt aerosols in the marine boundary layer

    Disselkamp, R. S.; Chapman, E. G.; Barchet, W. R.; Colson, S. D.; Howd, C. D.

    Atomic bromine and chlorine liberated from sea-salt aerosol is thought to play an important role in chemistry of the marine boundary layer. Despite numerous modeling studies, no prior experimental investigations of the oxidation of halide species contained in simulated, or actual, sea-salt solutions have been performed. We present laboratory data that examines chemistry in NaBr/NaCl/HNO3/O3 solutions at 290 K. Ozonation experiments were performed by flowing ozone in air through a nitric acid/salt solution and monitoring pH with time using an ion-sensitive electrode. The rate of oxidation was observed to be first order in ozone concentration and to have a non-first order bromide concentration dependence. Ion Chromatography was used to measure both bromide disappearance as well as oxidation products formed during the course of the reactions studied. Our measurements of the oxidation rate versus ion concentration indicate that the high ionic strength present in sea-salt aerosol will possess unique kinetics different from dilute solution behavior. In addition, our results are consistent with the reaction sequence O3 + H+ + Br- → O2 + HOBr and HOBr + Cl- + H+ → BrCl + H2O. These observations support the HOBr mediated Cl- oxidation process proposed previously (Vogt et al., 1996).

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

    D. S. Stevenson


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

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

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


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

  13. Absolute rate constant determinations for the deactivation of O/1D/ by time resolved decay of O/1D/ yields O/3P/ emission

    Davidson, J. A.; Sadowski, C. M.; Schiff, H. I.; Howard, C. J.; Schmeltekopf, A. L.; Jennings, D. A.; Streit, G. E.


    Absolute rate constants for the deactivation of O(1D) atoms by some atmospheric gases have been determined by observing the time-resolved emission of O(1D) at 630 nm. O(1D) atoms were produced by the dissociation of ozone via repetitive laser pulses at 266 nm. Absolute rate constants for the relaxation of O(1D) at 298 K are reported for N2, O2, CO2, O3, H2, D2, CH4, HCl, NH3, H2O, N2O, and Ne. The results obtained are compared with previous relative and absolute measurements reported in the literature.

  14. Ozone adsorption on carbon nanoparticles

    Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis


    Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles p. 967-973. [2] Smith, D. and A. Chughtai, Reaction kinetics of ozone at low concentrations with n-hexane soot. Journal of geophysical research, 1996. 101(D14): p. 19607-19,620. [3] Kamm, S., et al., The heterogeneous reaction of ozone with soot aerosol. Atmospheric Environment, 1999. 33(28): p. 4651-4661. [4] Stephens, S., M.J. Rossi, and D.M. Golden, The heterogeneous reaction of ozone on carbonaceous surfaces. International journal of chemical kinetics, 1986. 18(10): p. 1133-1149. [5] Pöschl, U., et al., Interaction of ozone and water vapor with spark discharge soot aerosol particles coated with benzo [a] pyrene: O3 and H2O adsorption, benzo [a] pyrene degradation, and atmospheric implications. The Journal of Physical Chemistry A, 2001. 105(16): p. 4029-4041.

  15. Regional Warming by Black Carbon and Tropospheric Ozone:A Review of Progresses and Research Challenges in China


    Black carbon (BC) aerosol and tropospheric ozone (O3) are major air pollutants with short lifetimes of days to weeks in the atmosphere. These short-lived species have also made signifi cant contributions to global warming since the preindustrial times (IPCC, 2013). Reductions in short-lived BC and tropospheric O3 have been proposed as a complementary strategy to reductions in greenhouse gases. With the rapid economic development, concentrations of BC and tropospheric O3 are relatively high in China, and therefore quantifying their roles in regional climate change is especially important. This review summarizes the existing knowledge with regard to impacts of BC and tropospheric O3 on climate change in China and defi nes critical gaps needed to assess the climate benefi ts of emission control measures. Measured concentrations of BC and tropospheric O3, optical properties of BC, as well as the model estimates of radiative forcing by BC and tropospheric O3 are summarized. We also review regional and global modeling studies that have investigated climate change driven by BC and tropospheric O3 in China;predicted sign and magnitude of the responses in temperature and precipitation to BC/O3 forcing are presented. Based on the review of previous studies, research challenges pertaining to reductions in short-lived species to mitigate global warming are highlighted.

  16. The importance of using dynamical a-priori profiles for infrared O3 retrievals : the case of IASI.

    Peiro, H.; Emili, E.; Le Flochmoen, E.; Barret, B.; Cariolle, D.


    Tropospheric ozone (O3) is a trace gas involved in the global greenhouse effect. To quantify its contribution to global warming, an accurate determination of O3 profiles is necessary. The instrument IASI (Infrared Atmospheric Sounding Interferometer), on board satellite MetOP-A, is the more sensitive sensor to tropospheric O3 with a high spatio-temporal coverage. Satellite retrievals are often based on the inversion of the measured radiance data with a variational approach. This requires an a priori profile and the correspondent error covariance matrix (COV) as ancillary input. Previous studies have shown some biases ( 20%) in IASI retrievals for tropospheric column in the Southern Hemisphere (SH). A possible source of errors is caused by the a priori profile. This study aims to i) build a dynamical a priori profile O3 with a Chemistry Transport Model (CTM), ii) integrate and to demonstrate the interest of this a priori profile in IASI retrievals.Global O3 profiles are retrieved from IASI radiances with the SOFRID (Software for a fast Retrieval of IASI Data) algorithm. It is based on the RTTOV (Radiative Transfer for TOVS) code and a 1D-Var retrieval scheme. Until now, a constant a priori profile was based on a combination of MOZAIC, WOUDC-SHADOZ and Aura/MLS data named here CLIM PR. The global CTM MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) has been used with a linear O3 chemistry scheme to assimilate Microwave Limb Sounder (MLS) data. The model resolution of 2°x2°, with 60 sigma-hybrid vertical levels covering the stratosphere has been used. MLS level 2 products have been assimilated with a 4D-VAR variational algorithm to constrain stratospheric O3 and obtain high quality a priori profiles O3 above the tropopause. From this reanalysis, we built these profiles at a 6h frequency on a coarser resolution grid 10°x20° named MOCAGE+MLS PR.Statistical comparisons between retrievals and ozonesondes have shown better correlations and smaller biases for

  17. Arctic Ozone Depletion Observed by UARS MLS During the 1994-95 Winter

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Santee, M. L.; Read, W. G.; Flower, D. A.; Jarnot, R. F.; Zurek, R. W.


    During the unusually cold 1994-95 Arctic winter, the Microwave Limb Sounder observed enhanced chlorine monoxide (ClO) in late Dec and throughout Feb and early Mar. Late Dec ClO was higher than during any of the previous 3 years, consistent with the colder early winter. Between late Dec 1994 and early Feb 1995, 465 K (about 50 hPa) vortex-averaged ozone (03) decreased by about 15%, with local decreases of about 30%; additional local decreases of about 5% were seen between early Feb and early Mar. Transport calculations indicate that vortex-averaged chemical loss between late Dec and early Feb was about 20% at 465 K, with about 1/4 of that masked by downward transport of O3. This Arctic chemical O3 loss is not readily detectable in MLS column O3 data.

  18. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S


    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests.

  19. [Mechanism and pathway of the ozonation of nonylphenol in aqueous solution].

    Hu, Xiang; Li, Jin; Pi, Yun-Zheng; Wang, Jiang-Long


    20 mg/L nonylphenol solution was ozonized. The removal efficiency and the intermediate products were studied during the ozonation of nonylphenol, the possible reaction mechanism of the ozonation of nonylphenol was proposed. The experimental results indicate that there are two kinds of ozonation patterns, the oxidation by molecule O3 alone and by O3/*OH. Both ozonation patterns can remove nonylphenol completely within 18 minutes. However, the combined oxidation can remove 96% of the initial nonylphenol within 4 minutes, and it took 12 minutes in the single O3 molecule oxidation system. The formaldehyde was detected during the ozonation of nonylphenol. The concentration reached stability after 8 minutes during the oxidation by single O3 and gradually increased during the combined oxidation process.

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

    Takashi Kadono

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


    Jacek Leszczyński


    Full Text Available In this paper, the application of ozonation processes for stabilized landfill leachate treatment was investigated. The leachate came from a municipal sanitary landfill located nearby Bielsk Podlaski. The average values of its main parameters were: pH 8.23; COD 870 mgO2/dm3; BOD 90 mgO2/dm3; NH4+ 136.2 mgN/dm3; UV254 absorbance 0.312 and turbidity 14 NTU. The ozone dosages used were in the range of 115.5 to 808.5 mgO3/dm3 of the leachate. The maximum COD, color and UV254 absorbance removal wa.5 mgO3/dm3. After oxidation, the ratio of BOD/COD was increased from 0.1 up to 0.23.

  2. A novel tropopause-related climatology of ozone profiles

    Sofieva, V.F.; Tamminen, J.; Kyrola, E.; Mielonen, T.; Veefkind, J.P.; Hassler, B.; Bodeker, G.E.


    A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local tropopaus

  3. Concentrations, cumulative exposure and critical levels of ozone in Ireland

    Kluizenaar, Y. de; Aherne, J.; Farrell, E.P.


    Concentrations of tropospheric ozone (O3) and exceedance of critical levels to vegetation have been investigated and mapped for Ireland. Hourly ozone concentration data (1995–1997) at 7 seven monitoring stations and the CORINE landcover database, supported by a Geographical Information System, were

  4. Ozonation with ultrasonic enhancement of p-nitrophenol wastewater

    XU Xian-wen; SHI Hui-xiang; WANG Da-hui


    Synergetic effects for p-nitrophenol degradation were observed in the ozonation with ultrasonic enhancement. The enhancements of removal rate for p-nitrophenol and TOC were around 116% and 294% respectively in comparison with the individual ultrasound and ozonation systems. The synergetic phenomenon is attributed to two physicochemical mechanisms: (1)Ultrasound decomposes ozone causing augmentation of the activity of free radicals; (2) Ultrasonic wave increased the concentration of O3 in solution because of ultrasonic dispersion.

  5. Formation of oxidation byproducts from ozonation of wastewater.

    Wert, Eric C; Rosario-Ortiz, Fernando L; Drury, Doug D; Snyder, Shane A


    Disinfection byproduct (DBP) formation in tertiary wastewater was examined after ozonation (O(3)) and advanced oxidation with O(3) and hydrogen peroxide (O(3)/H(2)O(2)). O(3) and O(3)/H(2)O(2) were applied at multiple dosages to investigate DBP formation during coliform disinfection and trace contaminant oxidation. Results showed O(3) provided superior disinfection of fecal and total coliforms compared to O(3)/H(2)O(2). Color, UV absorbance, and SUVA were reduced by O(3) and O(3)/H(2)O(2), offering wastewater utilities a few potential surrogates to monitor disinfection or trace contaminant oxidation. At equivalent O(3) dosages, O(3)/H(2)O(2) produced greater concentrations of assimilable organic carbon (5-52%), aldehydes (31-47%), and carboxylic acids (12-43%) compared to O(3) alone, indicating that organic DBP formation is largely dependent upon hydroxyl radical exposure. Bromate formation occurred when O(3) dosages exceeded the O(3) demand of the wastewater. Bench-scale tests with free chlorine showed O(3) is capable of reducing total organic halide (TOX) formation potential by at least 20%. In summary, O(3) provided superior disinfection compared to O(3)/H(2)O(2) while minimizing DBP concentrations. These are important considerations for water reuse, aquifer storage and recovery, and advanced wastewater treatment applications.

  6. Millimeter wave spectroscopic measurements of stratospheric and mesospheric constituents over the Italian Alps: stratospheric ozone

    V. Romaniello


    Full Text Available Measurements of rotational lines emitted by middle atmospheric trace gases have been carried out from the Alpine station of Testa Grigia (45.9°N, 7.7°E, elev. 3500 m by means of a Ground-Based Millimeter-wave Spectrometer (GBMS. Observations of species such as O3, HNO3, CO, N2O, HCN, and HDO took place during 4 winter periods, from February 2004 to March 2007, for a total of 116 days of measurements grouped in about 18 field campaigns. By studying the pressure-broadened shape of emission lines the vertical distribution of the observed constituents is retrieved within an altitude range of ?17-75 km, constrained by the 600 MHz pass band and the 65 kHz spectral resolution of the back-end spectrometer. This work discusses the behavior of stratospheric O3 during the entire period of operation at Testa Grigia. Mid-latitude O3 columnar content as estimated using GBMS measurements can vary by large amounts over a period of very few days, with the largest variations observed in December 2005, February 2006, and March 2006, confirming that the northern winter of 2005-2006 was characterized by a particularly intense planetary wave activity. The largest rapid variation from maximum to minimum O3 column values over Testa Grigia took place in December 2006 and reached a relative value of 72% with respect to the average column content for that period. During most GBMS observation times much of the variability is concentrated in the column below 20 km, with tropospheric weather systems and advection of tropical tropospheric air into the lower stratosphere over Testa Grigia having a large impact on the observed variations in column contents. Nonetheless, a wide variability is also found in middle stratospheric GBMS O3 measurements, as expected for mid-latitude ozone. We find that O3 mixing ratios at ?32 km are very well correlated with the solar illumination experienced by air masses over the previous ?15 days, showing that already at 32 km

  7. [Removal of trace nitrobenzene in water by VUV/TiO2/O3].

    Yin, Jing-jing; Zhang, Peng-yi


    The removal of trace nitrobenzene in water by the ozone-enhanced VUV photocatalysis process (VUV/TiO2/O3) was investigated, in which low-pressure mercury lamp emitting 185 nm vacuum ultraviolet and titanium dioxide film coated on the titanium plate were used as light source and photocatalyst respectively. The results show that, VUV/TiO2/O3 is an effective method to remove trace nitrobenzene in water, and the pseudo-first-order rate constant of nitrobenzene in the VUV/TiO2/O3 process is 102.8% and 30.8% higher than that in the UV/TiO2/O3 and VUV/O3 respectively. And 50 microg/L nitrobenzene in deionized water is totally removed within 60 s by the VUV/TiO2/O3 process. Higher ozone dosage is beneficial to accelerate nitrobenzene degradation, and the apparent rate constant at ozone dosage of 1.52 mg/L is 134.4% higher than that without ozone addition. Though the rate constant is slightly decreased with increase of nitrobenzene concentration, 170 microg/L nitrobenzene is removed to below the detection limit within 2 min. Common species such bicarbonate and humic acid in water significantly inhibit the removal of nitrobenzene, and the apparent rate constant is reduced 82.9% and 71.6% respectively when 2 mmol/L bicarbonate and 3.2 mg/L humic acid are added into the water. The inverse of the apparent rate constant is linear with the bicarbonate concentration. Trace nitrobenzene in surface water containing bicarbonate and natural organic matter can be removed fast and effectively by the VUV/TiO2/O3 process, and 96% nitrobenzene with initial concentration of 90 microg/L is removed within 4 min and the UV absorbance at 254 nm is also reduced 80%.

  8. Ozone Depletion by Hydrofluorocarbons

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.


    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  9. A kinetic study of the reaction of ozone with ethylene in a smog chamber under atmospheric conditions

    XU Yongfu; JIA Long; GE Maofa; DU Lin; WANG Gengchen; WANG Dianxun


    Ozone is one of the key species in the processes of atmospheric chemistry, which can be taken as an indicator of oxidation capacity in the troposphere, The reaction of ozone with reactive gases is an important process in the troposphere. Experimental simulation equipment of smog chamber for atmospheric reactions is used to study the reaction of ozone with ethylene in real atmospheric environment with ozone concentrations of 100-200 ppb. The concentrations of ozone and ethylene were monitored during the reaction with the combination of Model 49C-O3 Analyzer and GC-FID. A rate constant of 1.01×10-18 (cm3.mol-1.s-1) was obtained at 286.5 K,under condition of which the half-life of ozone was 88 min. The results obtained from our experiments are in excellent agreement with those reported previously by other researchers under extremely Iow pressure in terms of matrix-isolation technology. This demonstrates that our equipment of smog chamber for atmospheric reactions is reliable, which can be used for further research of the processes of atmospheric reactions.

  10. Models for the physiological effects of short O3 exposures on plants

    Schut, H.E.


    Some published effects of ozone on plant photosynthesis and evaporation are detailed, and attempts were made to develop explanatory models of increasing complexity. Stomatal regulation, which keeps the CO2 concentration inside the lead constant, is assumed. The O3 concentration inside the leaf is as

  11. Investigation of the influence of liquid surface films on O3 and PAN deposition to plant leaves coated with organic/inorganic solution

    Sun, Shang; Moravek, Alexander; Trebs, Ivonne; Kesselmeier, Jürgen; Sörgel, Matthias


    This study investigates the influence of leaf surface water films on the deposition of ozone (O3) and peroxyacetyl nitrate (PAN) under controlled laboratory conditions. A twin-cuvette system was used to simulate environmental variables. We observed a clear correlation between the O3 deposition on plants (Quercus ilex) and the relative humidity (RH) under both light and dark conditions. During the light period the observed increase of the O3 deposition was mainly attributed to the opening of leaf stomata, while during the absence of light the liquid surface films were the reason for O3 deposition. This finding was supported by experimentally induced stomatal closure by the infiltration of abscisic acid. In the case of PAN, no relationship with RH was found during the dark period, which indicates that the nonstomatal deposition of PAN is not affected by the liquid surface films. Consequently, the ratio of the O3 and PAN deposition velocities is not constant when relative humidity changes, which is in contrast to assumptions made in many models. The flux partitioning ratio between nonstomatal and stomatal depositions as well as between nonstomatal and total depositions was found to be Rnsto/sto = 0.21-0.40, Rnsto/tot = 0.18-0.30 for O3 and Rnsto/sto = 0.26-0.29, Rnsto/tot = 0.21-0.23 for PAN. Furthermore, we demonstrate that the formation of the liquid surface film on leaves and the nonstomatal O3 deposition are depending on the chemical composition of the particles deposited on the leaf cuticles as proposed previously.

  12. Ozone photolysis of paracetamol in aqueous solution.

    Neamţu, Mariana; Bobu, Maria; Kettrup, Antonius; Siminiceanu, Ilie


    The degradation of a paracetamol (N-acetil-para-aminofenol) aqueous solution (C (0) P = 5 mmol L(-1)) is studied in a bench-scale setup by means of simple ozonation (O3) and ozonation catalyzed with UV light (O3/UV) in order to quantify the influence of UV light on the degradation process. The results have shown that under the adopted experimental conditions (25°C, applied ozone dose = 9.8 mg L(-1) and gas flow rate of 20 L h(-1)) both oxidative systems are capable of removing the substrate with mineralization degrees up to 51% for ozonation and 53% for O3/UV. HPICE chromatography allowed the detection of nitrate ions and maleic and oxalic acids as ultimate carboxylic acids. The experimental data have been interpreted through 5 indicators: the conversion of paracetamol (XP ), the conversion degree of TOC (XTOC ), the apparent rate constant (kap ), the Hatta number (Ha) and the enhancement factor (E). The main advantage of photo-ozonation compared to simple ozonation was a more advanced conversion (79% vs. 92% after 90 min). The paracetamol decay follows a pseudo-first-order reaction with a superior rate constant (higher by 54%) for the UV catalyzed system in comparison with direct ozonation. Mineralization is slightly accelerated (+4%) in the O3/UV system, due to the additional production of hydroxyl radicals induced by the UV light and a higher Hatta number (+24%). Nevertheless, the process was still in the slow reaction kinetic regime (Ha < 0.3), and the enhancement factor was not significantly increased. The results are useful for the design and scale-up of the gas-liquid processes.

  13. Diurnal variations and source apportionment of ozone at the summit of Mount Huang, a rural site in Eastern China.

    Gao, J; Zhu, B; Xiao, H; Kang, H; Hou, X; Yin, Y; Zhang, L; Miao, Q


    Comprehensive measurements were conducted at the summit of Mount (Mt.) Huang, a rural site located in eastern China during the summer of 2011. They observed that ozone showed pronounced diurnal variations with high concentrations at night and low values during daytime. The Weather Research and Forecasting with Chemistry (WRF-Chem) model was applied to simulate the ozone concentrations at Mt. Huang in June 2011. With processes analysis and online ozone tagging method we coupled into the model system, the causes of this diurnal pattern and the contributions from different source regions were investigated. Our results showed that boundary layer diurnal cycle played an important role in driving the ozone diurnal variation. Further analysis showed that the negative contribution of vertical mixing was significant, resulting in the ozone decrease during the daytime. In contrast, ozone increased at night owing to the significant positive contribution of advection. This shifting of major factor between vertical mixing and advection formed this diurnal variation. Ozone source apportionment results indicated that approximately half was provided by inflow effect of ozone from outside the model domain (O3-INFLOW) and the other half was formed by ozone precursors (O3-PBL) emitted in eastern, central, and southern China. In the O3-PBL, 3.0% of the ozone was from Mt. Huang reflecting the small local contribution (O3-LOC) and the non-local contributions (O3-NLOC) accounted for 41.6%, in which ozone from the southerly regions contributed significantly, for example, 9.9% of the ozone originating from Jiangxi, representing the highest geographical contributor. Because the origin and variation of O3-NLOC was highly related to the diurnal movements in boundary layer, the similar diurnal patterns between O3-NLOC and total ozone both indicated the direct influence of O3-NLOC and the importance of boundary layer diurnal variations in the formation of such distinct diurnal ozone variations

  14. The Vaporization of B2O3(l) to B2O3(g) and B2O2(g)

    Jacobson, Nathan S.; Myers, Dwight L.


    The vaporization of B2O3 in a reducing environment leads to formation of both B2O3(g) and B2O2(g). While formation of B2O3(g) is well understood, many questions about the formation of B2O2(g) remain. Previous studies using B(s) + B2O3(l) have led to inconsistent thermodynamic data. In this study, it was found that after heating, B(s) and B2O3(l) appear to separate and variations in contact area likely led to the inconsistent vapor pressures of B2O2(g). To circumvent this problem, an activity of boron is fixed with a two-phase mixture of FeB and Fe2B. Both second and third law enthalpies of formation were measured for B2O2(g) and B2O3(g). From these the enthalpies of formation at 298.15 K are calculated to be -479.9 +/- 41.5 kJ/mol for B2O2(g) and -833.4 +/- 13.1 kJ/mol for B2O3(g). Ab initio calculations to determine the enthalpies of formation of B2O2(g) and B2O3(g) were conducted using the W1BD composite method and show good agreement with the experimental values.

  15. Modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides

    Ganzeveld, L.N.; Ammann, C.; Loubet, B.


    Vegetation canopies are efficient in removing ozone (O3) from the atmosphere making surface dry deposition an important process in air quality but also in climate change. O3 is the 3rd most important greenhouse gas (IPCC) responsible for ~25 % of the total net radiative forcing attributed to human

  16. Interaction between gaseous ozone and crystalline potassium bromide

    Levanov, A. V.; Maksimov, I. B.; Isaikina, O. Ya.; Antipenko, E. E.; Lunin, V. V.


    The formation of nonvolatile products of the oxidation of a bromide ion during the interaction between gaseous ozone and powdered crystalline KBr is studied. It is found that potassium bromate KBrO3 is the main product of the reaction. The influence of major experimental factors (the duration of ozonation, the concentration of ozone, the humidity of the initial gas, and the temperature) on the rate of formation of bromate is studied. The effective constants of the formation of bromate during the interaction between O3 and Br- in a heterogeneous gas-solid body system and in a homogeneous aqueous solution are compared.

  17. The mechanism and pathway of the ozonation of 4-chlorophenol in aqueous solution

    PI; Yunzheng


    The removal efficiency of 4-chlorophenol by ozonation was studied, and the reaction mechanism and characteristic of ozonation of 4-chlorophenol were investigated. Ozone and hydroxyl radicals are two strong oxidants during the process of ozonation. The experimental results showed that when there was no scavenger to inhibit OH· radicals, an intermediate product, hydrogen peroxide was formed during the ozonation of 4-chlorophenol. Hydrogen peroxide reacted with ozone at neutral pH and produced hydroxyl radicals. Ozone at the dosage of 113 mg/L could remove 20 mg/L4-chlorophenol and 39% TOC. With the complete inhibition of hydroxyl radicals, molecular ozone could effectively destroy 4-chlorophenol to form 4-quinone, which was subsequently oxidized to formic acid and oxalic acid. Two reaction pathways of the degradation of 4-chlorophenol by ozone and O3/OH· were proposed in this study. Ozonation is an effective method for reducing 4-chlorophenol,and has potential to practical application.

  18. Prevention of Renal Injury After Induction of Ozone Tolerance in Rats Submitted to Warm Ischaemia

    E. Barber


    Full Text Available On the basis that ozone (O3 can upregulate cellular antioxidant enzymes, a morphological, biochemical and functional renal study was performed in rats undergoing a prolonged treatment with O3 before renal ischaemia. Rats were divided into four groups: (1 control, a medial abdominal incision was performed to expose the kidneys; (2 ischaemia, in animals undergoing a bilateral renal ischaemia (30 min, with subsequent reperfusion (3 h; (3 O3 + ischaemia, as group 2, but with previous treatment with O3 (0.5 mg/kg per day given in 2.5 ml O2 via rectal administration for 15 treatments; (4 O2 + ischaemia, as group 3, but using oxygen (O2 alone. Biochemical parameters as fructosamine level, phospholipase A, and superoxide dismutases (SOD activities, as well as renal plasma flow (RPF and glomerular filtration rate (GFR, were measured by means of plasma clearance of p-amino-hippurate and inulin, respectively. In comparison with groups 1 and 3, the RPF and GFR were significantly decreased in groups 2 and 4. Interestingly, renal homogenates of the latter groups yielded significantly higher values of phospholipase A activity and fructosamine level in comparison with either the control (1 and the O3 (3 treated groups. Moreover renal SOD activity showed a significant increase in group 3 without significant differences among groups 1, 2 and 4. Morphological alterations of the kidney were present in 100%, 88% and 30% of the animals in groups 2, 4 and 3, respectively. It is proposed that the O3 protective effect can be ascribed to the substantial possibility of upregulating the antioxidant defence system capable of counteracting the damaging effect of ischaemia. These findings suggest that, whenever possible, ozone preconditioning may represent a prophylactic approach for minimizing renal damage before transplantation.

  19. Raman study of the antiferromagnetic phase transitions in hexagonal Y MnO3 and LuMnO3

    Vermette, J.; Jandl, S.; Mukhin, A. A.; Ivanov, V. Yu; Balbashov, A.; Gospodinov, M. M.; Pinsard-Gaudart, L.


    The A1, E1 and E2 Raman active modes in hexagonal Y MnO3 and LuMnO3 single crystals are studied as a function of temperature and compared with previous measurements. In addition to anharmonicity, some phonon frequencies show below TN anomalous temperature dependences that reflect the atomic displacements while some other phonon frequencies are more sensitive to the spin-phonon coupling.

  20. Effects of long-term ambient ozone exposure on biomass and wood traits in poplar treated with ethylenediurea (EDU).

    Carriero, G; Emiliani, G; Giovannelli, A; Hoshika, Y; Manning, W J; Traversi, M L; Paoletti, E


    This is the longest continuous experiment where ethylenediurea (EDU) was used to protect plants from ozone (O3). Effects of long-term ambient O3 exposure (23 ppm h AOT40) on biomass of an O3 sensitive poplar clone (Oxford) were examined after six years from in-ground planting. Trees were irrigated with either water or 450 ppm EDU. Above (-51%) and below-ground biomass (-47%) was reduced by O3 although the effect was significant only for stem and coarse roots. Ambient O3 decreased diameter of the lower stem, and increased moisture content along the stem of not-protected plants (+16%). No other change in the physical wood structure was observed. A comparison with a previous assessment in the same experiment suggested that O3 effects on biomass partitioning to above-ground organs depend on the tree ontogenetic stage. The root/shoot ratios did not change, suggesting that previous short-term observations of reduced allocation to tree roots may be overestimated.

  1. Impact of Ozone Exposure on OPV Efficiency

    Palankar, Aneeket Jaisukhlal

    Organic solar cells are a considerable promise for alternate energy sources owing to their plentiful, easily accessible and renewable source of power. Degradation on organic film and anode layer are the major factors that determine device reliability and ozone can induce damage to these materials due to its strong oxidizing property. This study measured the sustainability of a type of organic photovoltaic (OPV) film (P3HT:PC71BM) and its anodes (Al and MoO3) to different levels of ozone environment and investigated the impact of ozone exposure on OPV film and anodes efficiency. The devices were fabricated in a Glove Box under controlled N2 atmosphere using Spin Coating and Physical Vapor Deposition and exposed to varied ozone concentrations, followed by J-V measurements to determine the Power Conversion Efficiency and Fill Factor. The effects of ozone exposure on the films were compared vs. the effects of exposure on complete devices with anodes (Al and MoO 3). The results show that the devices decay from normal efficiency (4%) to 0% in 12 hours under 300 ppb (+/-10%) ozone concentration and decay to 0% in 6 hours when the ozone concentration was 600 ppb (+/-10%), when only the polymer thin films are exposed. This established an inverse linear relationship between the decay rate and ozone exposure at high concentrations on the OPV films. Furthermore, the effect of exposure to ambient ozone concentration on the polymer films, which is 70 ppb (+/-15%), was also investigated and the devices were found to decay to 0% in 28 hours, which is much faster than expected. The decay resistance of complete devices when the polymer films are coated with thermally evaporated anodes (Al and MoO3) before exposure to 400 ppb ozone concentration was investigated. The average efficiency of the complete device after 2, 6, 10, 15, 28 and 42 hours exposure in 400 ppb ozone environment was 4.16% with a standard deviation of 0.12%. The test findings for the complete device with coated

  2. V2O5-TiO2-AlF3/Al2O3催化臭氧化降解3,4,5,6-四氯吡啶甲酸、苯乙酮和乙酸的性能%Catalytic Performance of V2O5-TiO2-AlF3/Al2O3 in Ozonation of 3,4,5,6-tetrachloropicolinic Acid, Acetophenone, Acetic Acid, Hydroxyl Radical in Aqueous Solution

    蒋燮强; 蓝小飞



  3. Anaerobic effluent disinfection using ozone: Byproducts formation

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.


    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15 mi

  4. Anaerobic effluent disinfection using ozone: Byproducts formation

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.


    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15 mi

  5. Degradation of Organic Pollutants in Water by Catalytic Ozonation

    LI Xin; YAO Jun-hai; QI Jing-yao


    Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental results indicate that Cu/Al2O3 has a very effective catalytic activity during the ozonation of organic pollutants in water. The optimum conditions for preparing Cu/Al2O3 were systematically investigated with the orthogonal testing method. Furthermore, the results also show that the surface properties of catalyst are not compulsory for effective oxidation.

  6. A brief history of stratospheric ozone research

    Rolf Müller


    Full Text Available Ozone is one of the most important trace species in the atmosphere. Therefore, the history of research on ozone has also received a good deal of attention. Here a short overview of ozone research (with a focus on the stratosphere is given, starting from the first atmospheric measurements and ending with current developments. It is valuable to study the history of ozone research, because much can be learned for current research from an understanding of how previous discoveries were made. Moreover, since the 1970s, the history of ozone research has also encompassed also the history of the human impact on the ozone layer and thus the history of policy measures taken to protect the ozone layer, notably the Montreal Protocol and its amendments and adjustments. The history of this development is particularly important because it may serve as a prototype for the development of policy measures for the protection of the Earth's climate.

  7. Origin of interface magnetism in BiMnO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures.

    Salluzzo, M; Gariglio, S; Stornaiuolo, D; Sessi, V; Rusponi, S; Piamonteze, C; De Luca, G M; Minola, M; Marré, D; Gadaleta, A; Brune, H; Nolting, F; Brookes, N B; Ghiringhelli, G


    Possible ferromagnetism induced in otherwise nonmagnetic materials has been motivating intense research in complex oxide heterostructures. Here we show that a confined magnetism is realized at the interface between SrTiO3 and two insulating polar oxides, BiMnO3 and LaAlO3. By using polarization dependent x-ray absorption spectroscopy, we find that in both cases the magnetism can be stabilized by a negative exchange interaction between the electrons transferred to the interface and local magnetic moments. These local magnetic moments are associated with magnetic Ti3+ ions at the interface itself for LaAlO3/SrTiO3 and to Mn3+ ions in the overlayer for BiMnO3/SrTiO3. In LaAlO3/SrTiO3 the induced magnetism is quenched by annealing in oxygen, suggesting a decisive role of oxygen vacancies in this phenomenon.

  8. Ozone inhalation modifies the rat liver proteome

    Whitney S. Theis


    Full Text Available Ozone (O3 is a serious public health concern. Recent findings indicate that the damaging health effects of O3 extend to multiple systemic organ systems. Herein, we hypothesize that O3 inhalation will cause downstream alterations to the liver. To test this, male Sprague-Dawley rats were exposed to 0.5 ppm O3 for 8 h/day for 5 days. Plasma liver enzyme measurements showed that 5 day O3 exposure did not cause liver cell death. Proteomic and mass spectrometry analysis identified 10 proteins in the liver that were significantly altered in abundance following short-term O3 exposure and these included several stress responsive proteins. Glucose-regulated protein 78 and protein disulfide isomerase increased, whereas glutathione S-transferase M1 was significantly decreased by O3 inhalation. In contrast, no significant changes were detected for the stress response protein heme oxygenase-1 or cytochrome P450 2E1 and 2B in liver of O3 exposed rats compared to controls. In summary, these results show that an environmentally-relevant exposure to inhaled O3 can alter the expression of select proteins in the liver. We propose that O3 inhalation may represent an important unrecognized factor that can modulate hepatic metabolic functions.

  9. Application of ozone based treatments of secondary effluents.

    Tripathi, Smriti; Pathak, Vinita; Tripathi, Devendra Mani; Tripathi, B D


    The present work was aimed at studying the efficiency of ozone in oxidation processes, coliform inactivation and Disinfection Byproducts (DBPs) formation, associated with the potential of ozone to increase the Biodegradable Dissolved Organic Carbon (BDOC) in secondary effluent with applied ozone doses of 5.0, 10.0 and 15.0 mg/L for contact times of 2, 5 and 10 min. The wastewater used in this work was collected from the Bhagwanpur Sewage Treatment Plant, Varanasi, India. Results of this experiment showed that 10 mg O(3)/L O(3) for 5 min exposure was found most suitable dose for highest degradation of COD, TOC, UV(254), color, turbidity and total nitrogen parameters. The inactivation range of microbial biomass range was found in between 95% and 98%. Experiment revealed the fact that aldehydes and carboxylic acid formation were significantly related with the ozone dose and exposure time and ozone might enhance the treatment efficiency of secondary effluent treatment.

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

    A. Inness


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

  11. An estimate of the stratospheric contribution to springtime tropospheric ozone maxima using TOPSE measurements and beryllium-7 simulations

    Allen, Dale J.; Dibb, Jack E.; Ridley, Brian; Pickering, Kenneth E.; Talbot, Robert W.


    Measurements of tropospheric ozone (O3) between 30°N and 70°N show springtime maxima at remote locations. The contribution of seasonal changes in stratosphere-troposphere exchange (STE) to these maxima was investigated using measurements from the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) campaign and the beryllium-7 (7Be) distribution from a calculation driven by fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). Comparison with TOPSE measurements revealed that upper tropospheric model-calculated 7Be mixing ratios were reasonable (a change from previous calculations) but that lower tropospheric mixing ratios were too low most likely due to an overestimation of scavenging. Temporal fluctuations were well captured although their amplitudes were often underestimated. Analysis of O3 measurements indicated that O3 mixing ratios increased by 5-10% month-1 for θ underworld) and by 10-15% month-1 for θ > 300 K (the tropospheric middleworld). 7Be mixing ratios decreased with time for θ 300 K. Model-calculated middleworld increases of 7Be were a factor of 2 less than measured increases. 7Be with a stratospheric source (strat-7Be) increased by 4.6-8.8% month-1 along TOPSE flight paths within the tropospheric middleworld. Increases in strat-7Be were not seen along TOPSE flight paths in the underworld. Assuming changes in tropospheric O3 with a stratospheric source are the same as changes in strat-7Be and that 50% of O3 in the region of interest is produced in the stratosphere, changes in STE explain 20-60% of O3 increases in the tropospheric middleworld and less than 33% of O3 increases in the underworld.

  12. Ozone production and losses in N2/O2 mixtures in an ozone generator

    Mankelevich, Yu. A.; Poroykov, A. Yu.; Rakhimova, T. V.; Voloshin, D. G.; Chukalovskii, A. A.; Zosimov, A. V.; Lunin, V. V.; Samoilovich, V. G.


    Nonunique ozone concentrations at the output of an ozone generator under identical external conditions of barrier discharge activation of N2/O2 mixtures but with different prehistories of operating practice and employed gas mixtures are investigated theoretically. An analytical approach is developed to determine the ozone yield with regard for its heterogeneous loss. Plasma-chemical and electron kinetics in the N2/O2-mixtures are calculated numerically. The results of numerical calculations are compared to experimental data obtained by the authors. It is noted that the heterogeneous loss of ozone is the probable reason for the observed variety of behavior of O3 concentrations, depending on prehistory of ozone generator operation, along with the N2 and O2 gas flow rates and the specific active power.

  13. Ozone and urban forests in Italy.

    Paoletti, Elena


    Ozone levels along urban-to-rural gradients in three Italian cities (Milan, Florence, Bari) showed that average AOT40 values at rural and suburban sites were 2.6 times higher than those determined at urban sites. However, O(3) also exceeded the European criteria to protect forest health at urban sites, even when the standards for human health protection were met. For protecting street trees in Mediterranean cities, the objectives of measurement at urban sites should extend from the protection of human health to the protection of vegetation as well. A review of forest effects on O(3) pollution and of O(3) pollution on forest conditions in Italian cities showed that it was not possible to distinguish the effect of O(3) in the complex mixture of urban pollutants and stressors. A preliminary list of tree species for urban planning in the Mediterranean area shows the average tree capacity of O(3) removal and VOC emission.

  14. Treatment of Nematodes with Ozone Gas: A Sustainable Alternative to Nematicides

    Msayleb, Nahed; Ibrahim, Saiid

    This study tests Ozone as a Nematicides' alternative. Nematode-infected soil samples were treated with ascending doses of O3 by submerging the outlet of an "MB1000 Ozone Generator" in the 40 ml samples; then to test the O3 nematicidal effect by gas fumigation, Ozone gas was released into a sealed bag containing 80 g of each of the 6 nematode-infected soil samples with ascending doses and a repetition of each. With water-ozonation, 900 mg O3 were needed to kill 100% of nematodes, and the O3-Nematodes LD50 was identified by 420 mg. With the second experiment, O3 soil fumigation for 50 minutes at a dose of 1,125 mg in an air volume of 5 litres, were needed to control 95% of living nematodes.

  15. Stratospheric ozone

    M. Gil


    Full Text Available Stratospheric ozone acquired a huge importance two decades ago because of the discovery of strong anomalies above the Antarctica due to gases of anthropogenic origin. From that date, stratosphere has become one of the research lines receiving more funding. A result, an important progress in the development of observational techniques, the understanding of the dynamics of the polar regions and, above all, in understanding of the chemical interactions among the species that influence the chemical-radiative balance of ozone. In this article a general revision is made of the distribution of the ozone in the stratosphere, the mechanisms that determine its equilibrium, the gases that contribute to its destruction, the present situation and the forecast of the health state of the layer.

  16. Measurements of self-broadening of infrared absorption lines of ozone

    Smith, M. A. H.; Rinsland, C. P.; Devi, V. M.


    Lorentz self-broadening coefficients have been determined for 355 spectral lines belonging to five different infrared vibration-rotation bands of O3 in the spectral region from 4.8 to 17 microns. Six ozone absorption spectra, recorded at room temperature using a Fourier transform spectrometer, were analyzed. The half-width values were obtained through a nonlinear least-squares spectral fitting procedure. The results are compared with previous measurements, and the vibration of the half-widths with vibrational and rotational quantum numbers is examined.

  17. Laser Spectroscopic Study on Oxygen Isotope Effects in Ozone Surface Decomposition

    Minissale, Marco; Boursier, Corinne; Elandaloussi, Hadj; Te, Yao; Jeseck, Pascal; Rouille, Christian; Zanon-Willette, Thomas; Janssen, Christof


    The isotope kinetics of ozone formation in the Chapman reaction [1] O + O2 + M → O3 + M (1) provides the primary example for a chemically induced oxygen isotope anomaly and is associated with large [2] and mass independent [3] oxygen isotope enrichments in the product molecule, linked to a symmetry selection in the ozone formation kinetics [4-5]. The isotopic composition of ozone and its transfer to other molecules is a powerful tracer in the atmospheric and biogeochemical sciences [6] and serves as a primary model for a possible explanation of the oxygen isotopic heterogeneity in the Solar system [7-8]. Recently, the isotope fractionation in the photolytic decomposition process O3 + hν → O2 + O (2) using visible light has been studied in detail [9-10]. Much less is currently known about the isotope fractionation in the dry deposition or in the gas phase thermal decomposition of ozone O3 + M → O2 + O +M. (3) Here we report on first spectroscopic studies of non-photolytic ozone decomposition using a cw-quantum cascade laser at 9.5 μm. The concentration of individual ozone isotopomers (16O3,16O16O17O, and 16O17O16O) in a teflon coated reaction cell is followed in real time at temperatures between 25 and 150 °C. Observed ozone decay rates depend on homogeneous (reaction (3)) processes in the gas phase and on heterogeneous reactions on the wall. A preliminary analysis reveals agreement with currently recommended ozone decay rates in the gas phase and the absence of a large symmetry selection in the surface decomposition process, indicating the absence of a mass independent fractionation effect. This result is in agreement with previous mass spectrometer (MS) studies on heterogeneous ozone formation on pyrex [11], but contradicts an earlier MS study [12] on ozone surface decomposition on pyrex and quartz. Implications for atmospheric chemistry will be discussed. [1] Morton, J., Barnes, J., Schueler, B. and Mauersberger, K. J. Geophys. Res. 95, 901 - 907 (1990

  18. Numerical Study of the Simultaneous Oxidation of NO and SO2 by Ozone

    Bo Li


    Full Text Available This study used two kinetic mechanisms to evaluate the oxidation processes of NO and SO2 by ozone. The performance of the two models was assessed by comparisons with experimental results from previous studies. The first kinetic mechanism was a combined model developed by the author that consisted of 50 species and 172 reactions. The second mechanism consisted of 23 species and 63 reactions. Simulation results of both of the two models show under predictions compared with experimental data. The results showed that the optimized reaction temperature for NO with O3 ranged from 100~200 °C. At higher temperatures, O3 decomposed to O2 and O, which resulted in a decrease of the NO conversion rate. When the mole ratio of O3/NO was greater than 1, products with a higher oxidation state (such as NO3, N2O5 were formed. The reactions between O3 and SO2 were weak; as such, it was difficult for O3 to oxidize SO2.

  19. Tropospheric and Stratospheric Ozone From Assimilation of Aura Data

    Stajner, I.; Wargan, K.; Chang, L.; Hayashi, H.; Pawson, S.; Froidevaux, L.; Livesey, N.; Bhartia, P. K.; Bowman, K.


    Ozone is an atmospheric trace gas with multiple impacts on the environment. Global ozone fields are needed for air quality predictions, estimation of the ultraviolet radiation reaching the surface, climate-radiation studies, and ozone may also have an impact on longer-term weather predictions. We estimate global ozone fields in the stratosphere and troposphere by combining the data from the EOS Aura satellite with an ozone model using data assimilation. Ozone exhibits a large temporal variability in the lower stratosphere. Our previous work showed that assimilation of satellite data from limb-sounding geometry helps constrain ozone profiles in that region. We assimilated ozone data from the Aura Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) into the ozone system at NASA's Global Modeling and Assimilation Office (GMAO). Ozone is transported within a general circulation model (GCM) which includes parameterizations for stratospheric photochemistry, tropospheric chemistry, and a simple scheme for heterogeneous ozone loss. The focus of this study is on the representation of ozone in the lower stratosphere and tropospheric ozone columns. We plan to extend studies of tropospheric ozone distribution through assimilation of ozone data from the Tropospheric Emission Spectrometer (TES). Comparisons with ozone sondes and occultation data show that assimilation of Aura data provides a good representation of ozone gradients and variability in the lower stratosphere. We proceed by separating the contributions to temporal changes in the ozone field into those that are due to the model and those that are due to the assimilation of Aura data. We discuss the impacts of Aura data and their role in the representation of ozone variability in the lower stratosphere and troposphere.

  20. The Use of Ozone Gas for Medical Purposes

    Mehmet Ozler


    Full Text Available Ozone (O3 is a colorless and sharp odorous natural gas that is composed of three oxygen atoms. Ozone, that is toxic and pollutant near earth’s surface, it is vital in stratosphere by absorbing harmful ultraviolet radiation. Although initial years after being discovered it was used for disinfection, studies conducted have come into question for medical usage of ozone. Ozone therapy may be summarized as administering a particular amount of ozone/oxygen mixture into body cavities or circulation. Ozone/oxygen gas mixture can be applied via intravenous, intramuscular, intraarticular, intrapleural, intrarectal and intradiscal as well as topically. Most frequent ozone administration is major autohemotherapy. In this method, 50-270 ml blood of patient is taken into a special bottle and after contacting with ozone/oxygen mixture for a particular duration, it is re-infused. During this period, hydrogen peroxide produced by oxidative stress and lipid oxidations mediates the biological effects of ozone therapy by acting as a second messenger. Repetition of ozone administration creates resistance against oxidative stress via inducing antioxidative system. Moreover, levels of several cytokine are increased depending on the fatty acid oxidation in cell membranes. Ozone therapy is used as an adjuvant therapeutic modality in the pathophysiological conditions where severe inflammatory processes and immune activation are involved. Some of the examples are wound healing, age-dependent macular degeneration, ischemic and infectious disorders. [TAF Prev Med Bull 2009; 8(1.000: 69-74

  1. The Study Into Potential Enhacement Of Metalworking Fluids Biodegradability By The Application Of O3/UV

    Gerulová Kristína


    Full Text Available The increase in mineralization and biodegradability of MWFs by ozone/ultraviolet in comparison with ozone were investigated. Studied were two similar synthetic fluids pre-treated by the combination of the O3/UV advanced oxidative method. Expectations that the pre-treatment could enhance biodegradability of the metalworking fluid were not confirmed. The combined oxidation process at the defined conditions resulted in 1-35 % decrease of the achieved primary degradation level. Samples were prepared from real concentrates and diluted to approximately 350 mg/L of TOC.

  2. Effect of Humidity on the Interaction of Dimethyl Methylphosphonate (DMMP) Vapor with SiO2 and Al2O3 Surfaces, Studied Using Infrared Attenuated Total Reflection Spectroscopy


    prism faces. Spectrawere recordedusingaFourier transform infrared ( FTIR ) spectrometer with a “narrow-band” HgxCd1-xTe (MCT-A) detec- tor. No polarizer...was used, and the intrinsic polarization of the beam produced by an FTIR spectrometer is typically fairly weak.56 Usually 2000 scans were averaged at...scattering.49 2.3. Sample Preparation and Characterization. Follow- ing previous3-5 work, the a-SiO2/Si samples were grown using ultraviolet/ ozone (UV/O3

  3. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    Chen, Min

    period of 2003-2010. Ecosystem heterotrophic respiration (RH) was negatively affected by the aerosol loading. These results support previous conclusions of the advantage of aerosol light scattering effect on plant productions in other studies but suggest there is strong spatial variation. This study finds indirect aerosol effects on terrestrial ecosystem carbon dynamics through affecting plant phenology, thermal and hydrological environments. All these evidences suggested that the aerosol direct radiative effect on global terrestrial ecosystem carbon dynamics should be considered to better understand the global carbon cycle and climate change. An ozone sub-model is developed in this dissertation and fully coupled with iTem. The coupled model, named iTemO3 considers the processes of ozone stomatal deposition, plant defense to ozone influx, ozone damage and plant repairing mechanism. By using a global atmospheric chemical transport model (GACTM) estimated ground-level ozone concentration data, the model estimated global annual stomatal ozone deposition is 234.0 Tg O3 yr-1 and indicates which regions have high ozone damage risk. Different plant functional types, sunlit and shaded leaves are shown to have different responses to ozone. The model predictions suggest that ozone has caused considerable change on global terrestrial ecosystem carbon storage and carbon exchanges over the study period 2004-2008. The study suggests that uncertainty of the key parameters in iTemO3 could result in large errors in model predictions. Thus more experimental data for better model parameterization is highly needed.

  4. Superior solid solubility of MnSiO3 in CaSiO3 perovskite

    Li, Lin; Nagai, Takaya; Seto, Yusuke; Fujino, Kiyoshi; Kawano, Jun; Itoh, Shoich


    The silicate perovskite phase relation between CaSiO3 and MnSiO3 was investigated at 35-52 GPa and at 1,800 K using laser-heated diamond anvil cells combined with angle-dispersive synchrotron X-ray diffraction and energy-dispersive X-ray spectroscopic chemical analyses with scanning or transmission electron microscopy. We found that MnSiO3 can be incorporated into CaSiO3 perovskite up to 55, and 20 mol % of CaSiO3 is soluble in MnSiO3 perovskite. The range of 55-80 mol % of MnSiO3 in the CaSiO3-MnSiO3 perovskite system could be immiscible. We also observed that the two perovskite structured phases of the Mn-bearing CaSiO3 and the Ca-bearing MnSiO3 coexisted at these conditions. The Mn-bearing CaSiO3 perovskite has non-cubic symmetry and the Ca-bearing MnSiO3 perovskite has an orthorhombic structure with space group Pbnm. All the perovskite structured phases in the CaSiO3-MnSiO3 system convert to the amorphous phase during pressure release. MnSiO3 is the first chemical component confirmed to show such a superior solid solubility in CaSiO3 perovskite.

  5. [Investigation of the oxidation reaction of O3 with bromide ion in aqueous solution].

    Yu, Xiao-Ting; Zhang, Jia-Hui; Pan, Xun-Xi; Zhang, Ren-Xi; Hou, Hui-Qi


    The reaction mechanism of O3 with bromide ion in aqueous solution was studied by ion chromatography and UV-Vis spectrometry instruments. Ion chromatography analysis showed that only 10% of Br- which was oxidized by ozone was formed into bromate ion. The results demonstrated that the final products of the oxidation reaction were identified as Br2 and Br3- except for BrO3-. The formation of Br3- which was yielded from the reaction of Br2 with Br- was the major process in the reaction of Br attacked by O3. The characteristic absorption spectrum of Br3- with an absorption peak at 260 nm was also investigated. The results may provide helpful information about the mechanism of the oxidation reaction of Br- with O3 and fate of Br- or its derivatives in the environment by the oxidation processes.

  6. Sensitivity of bronchoprovocation and tracheal mucous velocity in detecting airway responses to O3. [Sheep

    Abraham, W.M.; Januszkiewicz, A.J.; Mingle, M.; Welker, M.; Wanner, A.; Sackner, M.A.


    This study was undertaken to determine whether measurements of tracheal mucous velocity or airway reactivity to inhaled carbachol more sensitively detect airway effects of inhaled ozone (O3) in conscious sheep. Dose-response curves of mean pulmonary flow resistance (RL) to carbachol were obtained by measuring RL after five breaths of carbachol aerosol with stepwise increases in drug concentration. The animals then breathed 0.5 ppM O3 through an endotracheal tube for 2 h. The dose-response curves were repeated immediately after the 0.5 ppM O3 exposure and 24 h later. In conscious sheep, airway hyperreactivity appears to be a more sensitive indicator of airway effects produced by short-term exposure to 0.5 ppM O3 than depression of tracheal mucous velocity.

  7. Hydrological controls on the tropospheric ozone greenhouse gas effect

    Le Kuai


    Full Text Available The influence of the hydrological cycle in the greenhouse gas (GHG effect of tropospheric ozone (O3 is quantified in terms of the O3longwave radiative effect (LWRE, which is defined as the net reduction of top-of-atmosphere flux due to total tropospheric O3absorption. The O3LWRE derived from the infrared spectral measurements by Aura’s Tropospheric Emission Spectrometer (TES show that the spatiotemporal variation of LWRE is relevant to relative humidity, surface temperature, and tropospheric O3column. The zonally averaged subtropical LWRE is ~0.2 W m-2higher than the zonally averaged tropical LWRE, generally due to lower water vapor concentrations and less cloud coverage at the downward branch of the Hadley cell in the subtropics. The largest values of O3LWRE over the Middle East (>1 W/m2 are further due to large thermal contrasts and tropospheric ozone enhancements from atmospheric circulation and pollution. Conversely, the low O3LWRE over the Inter-Tropical Convergence Zone (on average 0.4 W m-2 is due to strong water vapor absorption and cloudiness, both of which reduce the tropospheric O3absorption in the longwave radiation. These results show that changes in the hydrological cycle due to climate change could affect the magnitude and distribution of ozone radiative forcing.

  8. Connection between ozone concentration and atmosphere circulation at peak Moussala

    Nojarov, Peter; Ivanov, Peter; Kalapov, Ivo; Penev, Ilia; Drenska, Mirolujba


    Connection between ozone concentration and atmosphere circulation is investigated based on measurements at BEO station, peak Moussala (2,925 m a.s.l.), for the period 09 August 2006 to 29 January 2008. Ozone concentration data are collected with UV-analyzer “Environnement O3 42” and meteo data with weather station “Vaisala”. There are measurements of 7Be. Data from NOAA HYSPLIT model for particle trajectories are also used. Eight wind directions and three ranges of wind velocities are employed in the analysis. A comparison of ozone concentrations in upward and downward air transport according to HYSPLIT model is made. The number of cases with ozone concentration above 63 ppb has been counted. Mann-Whitney nonparametric test is employed as a basic statistical method. Correlation between atmosphere pressure and tropospheric ozone content is made. The same is done for 7Be and ozone. The main conclusion is that there is not any local or regional pollution effect detectable at peak Moussala, but most of the ozone measured is due to emissions of hydrocarbons and NO x over a larger region. There could be some regional sources of ozone building substances in southwest direction from peak Moussala. Air transported from the north quarter has higher ozone concentrations compared to the south quarter. In vertical direction, upward transport of air masses shows higher values of ozone concentration. Higher wind velocity is associated with low ozone concentrations at peak Moussala. The annual course of ozone concentration has summer maximum and winter minimum. There is right connection between air pressure and ozone concentration. The same is valid for the correlation between 7Be and ozone. Diurnal ozone course shows daytime maximum in winter and nighttime maximum in summer.

  9. The Antarctic Ozone Hole

    Jones, Anna E.


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

  10. Reactive uptake of ozone at simulated leaf surfaces: implications for ‘non-stomatal’ ozone deposition.

    Cape, J. Neil; Hamilton, Richard; Heal, Mathew R


    The reaction of ozone (O3) with alpha-pinene has been studied as a function of temperature and relative humidity and in the presence of wax surfaces that simulate a leaf surface. The objective was to determine whether the presence of a wax surface, in which alpha-pinene could dissolve and form a high surface concentration, would lead to enhanced reaction with O3. The reaction of O3 itself with the empty stainless steel reactor and with aluminium and wax surfaces demonstrated an apparent activ...

  11. 氧化铝催化臭氧氧化去除水中痕量嗅味物质%Catalytic ozonation by γ-Al2O3 for removal of taste and odor compounds (MIB and Geosmin) in the natural water

    齐飞; 陈忠林; 徐冰冰; 焦中志



  12. Qualitative and quantitative flow visualization technique using ozone

    Dickerson, R. R.; Stedman, D. H.


    The paper describes a new flow-visualization technique based on the absorption of ultraviolet light by ozone. Ozone is an excellent tracer, because as a gas it has the same effective physical properties as air. Ozone strongly absorbs the principal line (253.7 nm) of a mercury lamp, so that when an ozone-traced flow passes between a mercury lamp and a fluorescent screen, a sharp, shadow-like image of the ozone tracer is cast on the screen. Quantitative photometry can be carried out by replacing the screen with ultraviolet detectors that yield the path-integrated column density of ozone in the flow. High-speed quantitative point monitoring (10 Hz at 10 ppb O3) is possible with capillary probes and chemiluminescent analysis.

  13. Long-term trend of O3 in a mega City (Shanghai), China: Characteristics, causes, and interactions with precursors.

    Gao, Wei; Tie, Xuexi; Xu, Jianming; Huang, Rujin; Mao, Xiaoqing; Zhou, Guangqiang; Chang, Luyu


    In recent years, ozone (O3) is often the major pollutant during summertime in China. In order to better understand this problem, a long-term measurement of ozone (from 2006 to 2015) and its precursors (NOx and VOCs) as well as the photochemical parameter (UV radiation) in a mega city of China (Shanghai) is analyzed. The focus of this study is to investigate the trend of O3 and the causes of the O3 trend in large cities in China. In order to understand the relationship between the O3 precursors and O3 formation, two distinguished different sites of measurements are selected in the study, including an urbanization site (XJH-Xujiahui) and a remote site (DT-Dongtan). At the XJH site, there are high local emissions of ozone precursors (such as VOCs and NOx), which is suitable to study the effect of O3 precursors on O3 formation. In contrast, at the DT site, where there are low local emissions, the measured result can be used to analyze the background conditions nearby the city of Shanghai. The analysis shows that there were long-term trends of O3 and NOx concentrations at the urban site (XJH) from 2006 to 2015 (O3 increasing 67% and NOx decreasing 38%), while there were very small trends of O3 and NOx concentrations at the background site (DT). The analysis for causing the O3 trend suggests that (1) the large O3 increase at the urban area (XJH) was not due to the regional transport of O3; (2) the measurement of solar radiation had not significant trend during the period, and was not the major cause for the long-term O3 trend; (3) the measurement of VOCs had small change during the same period, suggesting that the trend in NOx concentrations at the urban site (XJH) was a major factor for causing the long-term change of O3 at the urban area of Shanghai. As a result, the O3 and NOx concentrations from 2006 to 2015 at the urban area of Shanghai were strongly anti-correlated, suggesting that the extremely high NOx concentration in the urban area depressed the O3

  14. Potential impacts of ambient ozone on wheat rust diseases and the role of plant ozone sensitivity

    The resurgence of rust diseases and the continued rise in tropospheric ozone (O3) levels have the potential to limit global wheat production. We conducted a series of experiments to understand the potential interactions between these two stress factors. Both stem rust and leaf rust were increased o...

  15. Transformation of anti-estrogenic-activity related dissolved organic matter in secondary effluents during ozonation.

    Tang, Xin; Wu, Qian-Yuan; Zhao, Xin; Du, Ye; Huang, Huang; Shi, Xiao-Lei; Hu, Hong-Ying


    Anti-estrogenic activity of dissolved organic matter (DOM) in reclaimed water is gaining increasing attention. In this study, anti-estrogenic activity removal efficiency by ozonation in the tertiary treatment process of domestic wastewater was investigated. The anti-estrogenic activity in the secondary effluents used in this study ranged between 0.95 and 2.00 mg-TAM L(-1) and decreased significantly after ozonation. The removal efficiency of anti-estrogenic activity at a dose of 10 mg-O3 L(-1) was 65-87%. The removal of the anti-estrogenic activity was highly correlated with the removal of UV254, suggesting that UV254 can be used as a surrogate for anti-estrogenic activity during ozonation. The results of size exclusion chromatography of the wastewater samples during ozonation showed that the UV254 absorbance of the DOM fraction with large apparent molecular weight (MW) around 7.6 k Da dropped significantly, and the DOM fraction was suspected to be humic substances which have been previously identified as anti-estrogenic constituents in secondary effluents. The excitation emission matrix fluorescence spectra of the wastewater samples proved that humic substances existed in the DOM and indeed reacted with the ozone. With the help of two-dimensional correlation of Fourier transform infrared, it was confirmed that the aromatic structures in the DOM were largely destroyed by ozonation. Therefore, it was suggested that the destruction of the aromatic structures in the DOM was related to the removal of the anti-estrogenic activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Tracer measurements in the tropical tropopause layer during the AMMA/SCOUT-O3 aircraft campaign

    Homan, C. D.; Volk, C. M.; Kuhn, A. C.; Werner, A.; Baehr, J.; Viciani, S.; Ulanovski, A.; Ravegnani, F.


    We present airborne in situ measurements made during the AMMA (African Monsoon Multidisciplinary Analysis)/SCOUT-O3 campaign between 31 July and 17 August 2006 on board the M55 Geophysica aircraft, based in Ouagadougou, Burkina Faso. CO2 and N2O were measured with the High Altitude Gas Analyzer (HAGAR), CO was measured with the Cryogenically Operated Laser Diode (COLD) instrument, and O3 with the Fast Ozone ANalyzer (FOZAN). We analyse the data obtained during five local flights to study the dominant transport processes controlling the tropical tropopause layer (TTL, here ~350-375 K) and lower stratosphere above West-Africa: deep convection up to the level of main convective outflow, overshooting of deep convection, and horizontal inmixing across the subtropical tropopause. Besides, we examine the morphology of the stratospheric subtropical barrier. Except for the flight of 13 August, distinct minima in CO2 mixing ratios indicate convective outflow of boundary layer air in the TTL. The CO2 profiles show that the level of main convective outflow was mostly located at potential temperatures between 350 and 360 K, and for 11 August reached up to 370 K. While the CO2 minima indicate quite significant convective influence, the O3 profiles suggest that the observed convective signatures were mostly not fresh, but of older origin (several days or more). When compared with the mean O3 profile measured during a previous campaign over Darwin in November 2005, the O3 minimum at the main convective outflow level was less pronounced over Ouagadougou. Furthermore O3 mixing ratios were much higher throughout the whole TTL and, unlike over Darwin, rarely showed low values observed in the regional boundary layer. Signatures of irreversible mixing following overshooting of convective air were scarce in the tracer data. Some small signatures indicative of this process were found in CO2 profiles between 390 and 410 K during the flights of 4 and 8 August, and in CO data at 410 K on 7

  17. Variations in O3, CO, and CH4 over the Bay of Bengal during the summer monsoon season: shipborne measurements and model simulations

    Girach, Imran A.; Ojha, Narendra; Nair, Prabha R.; Pozzer, Andrea; Tiwari, Yogesh K.; Kumar, K. Ravi; Lelieveld, Jos


    We present shipborne measurements of surface ozone (O3), carbon monoxide (CO), and methane (CH4) over the Bay of Bengal (BoB), the first time such measurements have been performed during the summer monsoon season, as a part of the Continental Tropical Convergence Zone (CTCZ) experiment during 2009. O3, CO, and CH4 mixing ratios exhibited significant spatial and temporal variability in the ranges of 8-54 nmol mol-1, 50-200 nmol mol-1, and 1.57-2.15 µmol mol-1, with means of 29.7 ± 6.8 nmol mol-1, 96 ± 25 nmol mol-1, and 1.83 ± 0.14 µmol mol-1, respectively. The average mixing ratios of trace gases over BoB in air masses from central/northern India (O3: 30 ± 7 nmol mol-1; CO: 95 ± 25 nmol mol-1; CH4: 1.86 ± 0.12 µmol mol-1) were not statistically different from those in air masses from southern India (O3: 27 ± 5 nmol mol-1; CO: 101 ± 27 nmol mol-1; CH4: 1.72 ± 0.14 µmol mol-1). Spatial variability is observed to be most significant for CH4 with higher mixing ratios in the air masses from central/northern India, where higher CH4 levels are seen in the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY) data. O3 mixing ratios over the BoB showed large reductions (by ˜ 20 nmol mol-1) during four rainfall events. Temporal changes in the meteorological parameters, in conjunction with O3 vertical profile, indicate that these low-O3 events are associated with downdrafts of free-tropospheric O3-poor air masses. While the observed variations of O3 and CO are successfully reproduced using the Weather Research and Forecasting model with Chemistry (WRF-Chem), this model overestimates mean concentrations by about 6 and 16 % for O3 and CO, respectively, generally overestimating O3 mixing ratios during the rainfall events. An analysis of modelled O3 along air mass trajectories show mean en route O3 production rate of about 4.6 nmol mol-1 day-1 in the outflow towards the BoB. Analysis of the various tendencies from model simulations during

  18. Application of heterogeneous catalytic ozonation as a tertiary treatment of effluent of biologically treated tannery wastewater.

    Huang, Guangdao; Pan, Feng; Fan, Guofeng; Liu, Guoguang


    The present study employed a Mn-Cu/Al2O3 heterogeneous catalytic ozonation process for tertiary treatment of actual tannery wastewater, focusing on its feasibility in that application. The primary factors affecting the removal efficiency of organic pollutants were investigated, including catalyst dosage, ozone dosage, and initial pH value. The experimental results showed that the addition of a Mn-Cu/Al2O3 catalyst improved the removal efficiency of chemical oxygen demand (COD) during ozonation, which initiated a 29.3% increase for COD removal, compared to ozonation alone after 60 min. The optimum pH, catalyst dosage, and ozone dosage were determined to be 7.0, 2.0 g/L, and 0.3 g/h, respectively. Under these conditions, following 60 min of reaction, the COD removal efficiency and the concentration in effluent were 88%, and 17 mg/L, respectively. In addition, the presence of tert-butanol (a well known hydroxyl radical scavenger) strongly inhibited COD removal via Mn-Cu/Al2O3 catalytic ozonation, indicating that the Mn-Cu/Al2O3 catalytic ozonation process follows a hydroxyl radical (OH·) reaction mechanism. The Mn-Cu/Al2O3 catalyst exhibited good stability and reusability. Finally, the kinetic analysis revealed that the apparent reaction rate constant of COD removal with the Mn-Cu/Al2O3 catalytic ozonation system (0.0328 min(-1)) was 2.3 times that of an ozonation system alone (0.0141 min(-1)). These results demonstrated that the catalytic ozonation using Mn-Cu/Al2O3 is an effective and promising process for tertiary treatment of tannery effluent in biological systems.

  19. Resonance Rayleigh Scattering Determination of Trace Ozone Based on the Cationic Surfactant Association Particles%基于阳离子表面活性剂缔合微粒共振瑞利散射光谱法测定痕量O3

    刘高伞; 梁爱惠; 温桂清; 蒋治良


    In the presence of pH 4.0 HAC-NaAC buffer solution ,using H3 BO3-KI (BKI) as absorption solution ,O3 oxidized KI to produce I2 ,and it reacted with excess I - to form I3- that combined with the cationic surfactant (CS) such as cetylpyridinium chloride (CPCl) ,tetradecyl pyridinium bromide (TPB) ,cetyl trimethyl ammonium bromide (CTMAB) ,and tetradecyl dimeth-ylbenzyl ammonium chloride (TDMAC) to produce stable (CS-I3 )n association particles ,which exhibited a strong resonance Rayleigh scattering (RRS) peak at 470 nm. Under the chosen conditions ,as the concentration of O3 (C) increased ,the concen-tration of I3- increased ,and the RRS intensity at 470 nm (I470 nm ) increased due to more association particles forming. The in-creased RRS intensity I470 nm was linear with O3 concentration. For the four CS systems ,the linear range was 15~50 ,50~100 ,5~25 and 1~50 μmol · L -1 O3 respectively. The regression equation is ΔI= 8.81c-4.01 ,ΔI= 5.44c-3.11 ,ΔI=15.39c-1.55 ,and ΔI=16.88c+0.51. The detection limit is 4.9 ,12 ,2.85 and 0.56 μmol · L -1 O3 respectively. The influ-ence of some foreign substances was examined on the determination of 2.5 × 10-6 mol · L -1 O3 ,within ± 10% relative error.Results showed that a 4.0 × 10-5 mol · L -1 Hg2+ ,8.7 × 10-5 mol · L -1 Fe3+ ,5.0 × 10-5 mol · L -1 Ca2+ ,2.5 × 10-5 mol · L -1 Zn2+ and Cu2+ ,2.8 × 10-6 mol · L -1 Pb2+ and Cr3+ ,4.2 × 10-5 mol · L -1 Mg2+ ,Mn2+ and Ba2+ do not interfere with the RRS determination. This showed that this RRS method is of good selectivity. The TDMAC system is most sensitive ,and was chosen to detect O3 in air samples. The analytical results were in agreement with that of spectrophotometry results .Further-more ,laser scattering technique was utilized to examine the particle size distribution of (TDMAC-I3 )n system. Results indicated that the particle size located in the range of 190~531 nm ,in the absence of O3. Upon addition of O3 ,the excess KI reacted with O3 to produce I3

  20. Acute O 3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment.

    Darbah, Joseph N T; Jones, Wendy S; Burton, Andrew J; Nagy, John; Kubiske, Mark E


    We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O(3) and/or CO(2) for 12 years, were harvested. Acute O(3) damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O(3) damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O(3) damage as it directly controlled O(3) uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O(3) exposure. Moreover, elevated CO(2) did not ameliorate the adverse effects of acute O(3) dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O(3) levels.

  1. Dissolution mechanism of Al2O3 in refining slags containing Ce2O3

    Wang L.J.


    Full Text Available In the present work, the rate of dissolution of Al2O3 rod in CaO-SiO2-Al2O3 and CaO-SiO2-Al2O3-Ce2O3 slags were carried out in the temperature range of 1793 K (1520ºC - 1853 K (1580ºC under static conditions. The cross section of the rod and the boundary layers were identified and analyzed by SEM-EDS. The dissolution of Al2O3 was favored with the increasing CaO/Al2O3 ratio, elevating temperatures as well as the addition of Ce2O3. An intermediate product 3CaO5Al2O3Ce2O3 was detected. The mechanism of dissolution of Al2O3 in the Ce2O3 containing slag were also proposed as three steps involved: 1 the formation of calcium aluminates CaO•Al2O3 at the interface 2 the formation of 3CaO5Al2O3Ce2O3 as the reaction progresses; and 3 the dissolution of 3CaO5Al2O3Ce2O3 into the slag.

  2. Resistance switching of the interfacial conductance in amorphous SrTiO3 heterostructures

    Christensen, Dennis; Trier, Felix; Chen, Yunzhong

    Complex oxides have attracted a lot of interest recently as this class of material exhibits a plethora of remarkable properties. In particular, a great variety of properties is observed in the heterostructure composed of lanthanum aluminate (LaAlO3) and strontium titanate (SrTiO3). For instance...... by an electric field. It has previously been demonstrated that SrTiO3 heterostructures with amorphous LaAlO3 top layers can display interfacial conductivity with similar critical thickness dependence. Here, we report resistance switching of the interfacial conductance for SrTiO3 heterostructures with amorphous...

  3. Towards reducing DBP formation potential of drinking water by favouring direct ozone over hydroxyl radical reactions during ozonation.

    De Vera, Glen Andrew; Stalter, Daniel; Gernjak, Wolfgang; Weinberg, Howard S; Keller, Jurg; Farré, Maria José


    When ozonation is employed in advanced water treatment plants to produce drinking water, dissolved organic matter reacts with ozone (O3) and/or hydroxyl radicals (OH) affecting disinfection byproduct (DBP) formation with subsequently used chlorine-based disinfectants. This study presents the effects of varying exposures of O3 and •OH on DBP concentrations and their associated toxicity generated after subsequent chlorination. DBP formation potential tests and in vitro bioassays were conducted after batch ozonation experiments of coagulated surface water with and without addition of tertiary butanol (t-BuOH, 10 mM) and hydrogen peroxide (H2O2, 1 mg/mg O3), and at different pH (6-8) and transferred ozone doses (0-1 mg/mg TOC). Although ozonation led to a 24-37% decrease in formation of total trihalomethanes, haloacetic acids, haloacetonitriles, and trihaloacetamides, an increase in formation of total trihalonitromethanes, chloral hydrate, and haloketones was observed. This effect however was less pronounced for samples ozonated at conditions favoring molecular ozone (e.g., pH 6 and in the presence of t-BuOH) over •OH reactions (e.g., pH 8 and in the presence of H2O2). Compared to ozonation only, addition of H2O2 consistently enhanced formation of all DBP groups (20-61%) except trihalonitromethanes. This proves that •OH-transformed organic matter is more susceptible to halogen incorporation. Analogously, adsorbable organic halogen (AOX) concentrations increased under conditions that favor •OH reactions. The ratio of unknown to known AOX, however, was greater at conditions that promote direct O3 reactions. Although significant correlation was found between AOX and genotoxicity with the p53 bioassay, toxicity tests using 4 in vitro bioassays showed relatively low absolute differences between various ozonation conditions.

  4. MRI DWI/ADC signal predicts shrinkage of lumbar disc herniation after O2–O3 discolysis

    Perri, Marco; Grattacaso, Giuseppe; Di Tunno, Valeria; Marsecano, Claudia; Di Cesare, Ernesto; Gallucci, Massimo


    Purpose Evaluate the discal morpho-structural changes as a predictive sign in the clinical outcome after ozone therapy in lumbar disc herniation using the T2–shine through effect in diffusion-weighted imaging (DWI). Method One hundred and fifty-four patients suffering from lumbosciatica (89 men and 65 women; age range, 23–62 years) were included, previous MR study performed with FSE-T2 and T2-fat, SE-T1 and DWI sequences, and were randomly assigned to two groups. Seventy-seven patients (control group) underwent conservative treatment with intraforaminal injection of steroid and anaesthetic. The remaining 77 patients (study group) underwent the same treatment with the addition of oxygen–ozone (O2–O3). During the following six months, a MRI follow-up with the same sequences was performed. An intervertebral disc volumetric analysis (IDVA), DWI signal score and post treatment clinical outcome evaluation were performed for an assessment of hernia reduction. χ2 test, Student's t test and analysis of covariance were used for comparison of variables. Results In the study group, 58 of 77 patients had a successful outcome (responders). In the responders group, DWI T2–shine through effect was present during MRI follow-up and in particular in 53 of 77 patients in six months of follow-up (p < 0.05). Moreover, in the same group a statistically significant disc shrinkage was shown by IDVA in sixth months of follow-up (p < 0.05). Conclusions T2–shine through effect in DWI is present before morphological disc reduction and moreover could be considered as a predictive sign of response to oxygen–ozone treatment. PMID:25923680

  5. MRI DWI/ADC signal predicts shrinkage of lumbar disc herniation after O2-O3 discolysis.

    Perri, Marco; Grattacaso, Giuseppe; Di Tunno, Valeria; Marsecano, Claudia; Di Cesare, Ernesto; Splendiani, Alessandra; Gallucci, Massimo


    Evaluate the discal morpho-structural changes as a predictive sign in the clinical outcome after ozone therapy in lumbar disc herniation using the T2-shine through effect in diffusion-weighted imaging (DWI). One hundred and fifty-four patients suffering from lumbosciatica (89 men and 65 women; age range, 23-62 years) were included, previous MR study performed with FSE-T2 and T2-fat, SE-T1 and DWI sequences, and were randomly assigned to two groups. Seventy-seven patients (control group) underwent conservative treatment with intraforaminal injection of steroid and anaesthetic. The remaining 77 patients (study group) underwent the same treatment with the addition of oxygen-ozone (O2-O3). During the following six months, a MRI follow-up with the same sequences was performed. An intervertebral disc volumetric analysis (IDVA), DWI signal score and post treatment clinical outcome evaluation were performed for an assessment of hernia reduction. χ² test, Student's t test and analysis of covariance were used for comparison of variables. In the study group, 58 of 77 patients had a successful outcome (responders). In the responders group, DWI T2-shine through effect was present during MRI follow-up and in particular in 53 of 77 patients in six months of follow-up (p < 0.05). Moreover, in the same group a statistically significant disc shrinkage was shown by IDVA in sixth months of follow-up (p < 0.05). T2-shine through effect in DWI is present before morphological disc reduction and moreover could be considered as a predictive sign of response to oxygen-ozone treatment. © The Author(s) 2015 Reprints and permissions:

  6. Limitations of the removal of cyanide from coking wastewater by ozonation and by the hydrogen peroxide-ozone process.

    Pueyo, N; Miguel, N; Ovelleiro, J L; Ormad, M P


    The purpose of this study is to compare the efficiency of ozonation and the hydrogen peroxide-ozone process for the removal of cyanide from coking wastewater. The most efficient oxidation process is combined with coagulation-flocculation-decantation and lime-soda ash softening pretreatments. The oxidation in aqueous solution and industrial wastewater (at pH 9.5-12.3) by O3 was carried out using a range of concentration of consumed O3 from 10 to 290 mg/L. A molar ratio of H2O2/O3 from 0.1 to 5.2 with different concentrations of O3 constants was used for the H2O2-O3 process. The maximum cyanide removal obtained in coking wastewater was 90% using a mass ratio of O3/CN(-) of 9.5. Using lower concentrations of O3, cyanide is not removed and can even be generated due to the presence of other cyanide precursor organic micropollutants in the industrial matrix. The concentration of O3 is reduced to half for the same cyanide removal efficiency if the pretreatments are applied to reduce the carbonate and bicarbonate ions. The cyanide removal efficiency in coking wastewater is not improved if the O3 is combined with the H2O2. However, the preliminary cyanide removal treatment in aqueous solution showed an increase in the cyanide removal efficiency for the H2O2-O3 process.

  7. Earth's Endangered Ozone

    Panofsky, Hans A.


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

  8. Isotope effects in photo dissociation of ozone with visible light

    Früchtl, Marion; Janssen, Christof; Röckmann, Thomas


    Ozone (O3) plays a key role for many chemical oxidation processes in the Earth's atmosphere. In these chemical reactions, ozone can transfer oxygen to other trace gases. This is particularly interesting, since O3 has a very peculiar isotope composition. Following the mass dependent fractionation equation δ17O = 0.52 * δ18O, most fractionation processes depend directly on mass. However, O3 shows an offset to the mass dependent fractionation line. Processes, which show such anomalies, are termed mass independent fractionations (MIF). A very well studied example for a chemical reaction that leads to mass independent fractionation is the O3 formation reaction. To what degree O3 destruction reactions need to be considered in order to understand the isotope composition of atmospheric O3 is still not fully understood and an open question within scientific community. We set up new experiments to investigate the isotope effect resulting from photo dissociation of O3 in the Chappuis band (R1). Initial O3 is produced by an electric discharge. After photolysis O3 is collected in a cold trap at the triple point temperature of nitrogen (63K). O3 is then converted to O2 in order to measure the oxygen isotopes of O3 using isotope ratio mass spectrometry. To isolate O3 photo dissociation (R1) from O3 decomposition (R2) and secondary O3 formation (R3), we use varying amounts of carbon monoxide (CO) as O atom quencher (R4). In this way we suppress the O + O3 reaction (R3) and determine the isotope fractionation in R1 and R2 separately. We present first results on the isotope effects in O3 photo dissociation with visible light in the presence of different bath gases. Results are interpreted based on chemical kinetics modeling. (R1) O3 + hυ → O (3P) + O2 (R2) O3 + O (3P) → 2 O2 (R3) O + O2 + M → O3 + M (R4) O (3P) + CO + M → CO2 + M

  9. High ozone at rural sites in India

    Chand, D.; Lal, S.


    Past observations of O3 at urban, rural and lower free tropospheric sites in India have shown generally low values rarely exceeding 60 ppbv. We show that this can not be generated to all over India. Surface ozone (O3) concentrations are obtained from measurements in rural, urban and free tropospheric environments in January 2001 and 2002 as a part of Mobile Lab Experiments (MOLEX) conducted in western India. Elevated O3 from 70 to 110 ppbv (nmole/mole) are recorded during afternoon hours at rural sites in downwind of major industrial region of Gujarat adjoining the Arabian Sea. Repeated observations during both the years indicate that this is a regular process in this region. The average background ozone is found to be 42±6 ppbv. The elevated ozone in the downwind site is about 60% higher than that in the major urban center and its surroundings and by a factor of 2 higher than the background levels of O3 in this region. In comparison to the downwind observations; the ozone observed at the continental stations in rural (Gadanki), urban (Ahmedabad) and free tropospheric (Mt. Abu) sites in India are low and rarely exceeded 60 ppbv during the month of January. Forward trajectory analysis shows that the polluted plumes from this urban area can get transported more than 3000 km to the marine boundary layer over the Arabian Sea and the Indian Ocean within a week. Similar transport of pollutants from major urban sites like Delhi and other cities can enhance O3 in their downwind rural sites and can affect the human health as well as vegetation significantly.

  10. Ozone inhalation effects consequent to continuous exercise in females: comparison to males

    Lauritzen, S.K.; Adams, W.C.


    Exposure to ozone (O3) at ambient photochemical smog alert levels has been shown to cause alteration in pulmonary function and exercise response in humans, but there is a paucity of data on females. The initial purpose of the present investigation was to study the effects of O3 inhalation on pulmonary function and selected exercise respiratory metabolism and breathing pattern responses in young adult females. Six female subjects exercised continuously on a bicycle ergometer for 1 h on 10 occasions at one of three intensities, while exposed to 0.0, 0.20, 0.30, or 0.40 ppm O3. Forced expiratory volume and flow rates and residual volume (RV) were measured before and immediately following each protocol. During exercise, expired minute ventilation (VE), respiratory frequency (fR), tidal volume, O2 uptake (VO2), and heart rate (HR) were measured every 10 min. O3 dose-dependent decrements were observed for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), and forced expiratory flow rate during the middle half of FVC, coupled with an increase in RV and altered exercise ventilatory pattern. There was also an increased VE but no significant O3 effect on VO2 or HR. Comparison of the females' responses to those of a group of young adult males (previously studied) at the same total O3 effective dose (i.e., expressed as the simple product of O3 concentration, VE, and exposure time) revealed significantly greater effects on FVC, FEV1.0, and fR for the females. With VE reduced for females as a function of exercise intensity at the same percent of maximum VO2, these differences were considerably attenuated, although not negated.

  11. Egyptian plant species as new ozone indicators.

    Madkour, Samia A; Laurence, J A


    The aim of this study was to test and select one or more highly sensitive, specific and environmentally successful Egyptian bioindicator plants for ozone (O3). For that purpose more than 30 Egyptian species and cultivars were subjected to extensive screening studies under controlled environmental and pollutant exposure conditions to mimic the Egyptian environmental conditions and O3 levels in urban and rural sites. Four plant species were found to be more sensitive to O3 than the universally used O3-bioindicator, tobacco Bel W3, under the Egyptian environmental conditions used. These plant species, jute (Corchorus olitorius c.v. local), clover (Trifolium alexandrinum L. c.v. Masry), garden rocket (Eruca sativa c.v. local) and alfalfa (Medicago sativa L. c.v. local), ranked in order of decreasing sensitivity, exhibited typical O3 injury symptoms faster and at lower 03 concentrations than Bel W3. Three variables were tested in search of a reliable tool for the diagnosis and prediction of O3 response prior to the appearance of visible foliar symptoms: pigment degradation, stomatal conductance (g(s)) and net photosynthetic CO2 assimilation (Pnet). Pigment degradation was found to be unreliable in predicting species sensitivity to O3. Evidence supporting stomatal conductance involvement in 03 tolerance was found only in tolerant species. A good correlation was found between g(s), restriction of O3 and CO2 influx into the mesophyll tissues, and Pnet. Changes in Pnet seemed to depend largely on fluctuations in g(s).

  12. Secondary ozone peaks in the troposphere over the Himalayas

    Ojha, Narendra; Pozzer, Andrea; Akritidis, Dimitris; Lelieveld, Jos


    Layers with strongly enhanced ozone concentrations in the middle-upper troposphere, referred to as secondary ozone peaks (SOPs), have been observed in different regions of the world. Here we use the global ECHAM5/MESSy atmospheric chemistry model (EMAC) to (i) investigate the processes causing SOPs, (ii) explore both their frequency of occurrence and seasonality, and (iii) assess their effects on the tropospheric ozone budget over the Himalayas. The vertical profiles of potential vorticity (PV) and a stratospheric ozone tracer (O3s) in EMAC simulations, in conjunction with the structure of SOPs, suggest that SOPs over the Himalayas are formed by stratosphere-to-troposphere transport (STT) of ozone. The spatial distribution of O3s further shows that such effects are in general most pronounced in the northern part of India. Model simulated ozone distributions and backward air trajectories show that ozone rich air masses, associated with STT, originate as far as northern Africa and the North Atlantic Ocean, the Middle East, as well as in nearby regions in Afghanistan and Pakistan, and are rapidly (within 2-3 days) transported to the Himalayas. Analysis of a 15-year (2000-2014) EMAC simulation shows that the frequency of SOPs is highest during the pre-monsoon season (e.g. 11 % of the time in May), while no intense SOP events are found during the July-October period. The SOPs are estimated to enhance the tropospheric column ozone (TCO) over the central Himalayas by up to 21 %.

  13. Simulating ozone dry deposition at a boreal forest with a multi-layer canopy deposition model

    Zhou, Putian; Ganzeveld, Laurens; Rannik, Üllar; Zhou, Luxi; Gierens, Rosa; Taipale, Ditte; Mammarella, Ivan; Boy, Michael


    A multi-layer ozone (O3) dry deposition model has been implemented into SOSAA (a model to Simulate the concentrations of Organic vapours, Sulphuric Acid and Aerosols) to improve the representation of O3 concentration and flux within and above the forest canopy in the planetary boundary layer. We aim to predict the O3 uptake by a boreal forest canopy under varying environmental conditions and analyse the influence of different factors on total O3 uptake by the canopy as well as the vertical distribution of deposition sinks inside the canopy. The newly implemented dry deposition model was validated by an extensive comparison of simulated and observed O3 turbulent fluxes and concentration profiles within and above the boreal forest canopy at SMEAR II (Station to Measure Ecosystem-Atmosphere Relations II) in Hyytiälä, Finland, in August 2010. In this model, the fraction of wet surface on vegetation leaves was parametrised according to the ambient relative humidity (RH). Model results showed that when RH was larger than 70 % the O3 uptake onto wet skin contributed ˜ 51 % to the total deposition during nighttime and ˜ 19 % during daytime. The overall contribution of soil uptake was estimated about 36 %. The contribution of sub-canopy deposition below 4.2 m was modelled to be ˜ 38 % of the total O3 deposition during daytime, which was similar to the contribution reported in previous studies. The chemical contribution to O3 removal was evaluated directly in the model simulations. According to the simulated averaged diurnal cycle the net chemical production of O3 compensated up to ˜ 4 % of dry deposition loss from about 06:00 to 15:00 LT. During nighttime, the net chemical loss of O3 further enhanced removal by dry deposition by a maximum ˜ 9 %. Thus the results indicated an overall relatively small contribution of airborne chemical processes to O3 removal at this site.

  14. Changes in the surface ozone after the windstorm in 2004, in the High Tatras

    Bičárová Svetlana


    Full Text Available Extreme wind event in November 2004 caused spacious destruction of slope forests in the Tatra National Park, Slovakia. Relevant changes of land cover motivated researchers to investigate damaged forest ecosystem and its response to different environmental conditions. Surface ozone (O3 is a minor but not negligible compound of the ambient air. Control strategies for the reduction of O3 precursor emissions have been applied in Europe during the last two decades. In spite of these reductions, air quality indices for O3 suggest that highland sites are more vulnerable to health and environmental risk than lowlands where mostly emissions from road transport and industry are produced. Both anthropogenic sources and biogenic precursors (BVOC from forest vegetation play a relevant role in the tropospheric photochemistry, especially at mountainous and rural locations. The parameters of air quality are measured at background station Stará Lesná in the High Tatras region since 1992 in frame of an European project EMEP. Long-term data series (1992-2013 of O3 concentrations obtained for site Stará Lesná provide specific opportunity to investigate the response of BVOC reduction on O3 variability after windstorm 2004. Evaluation of these data indicates moderate increase of annual, monthly and hourly O3 means for the period from 2005 to 2013 in comparison with the previous period 1992-2004. Temporal interpolation shows evident changes of O3 concentrations, especially ~30% increase for night hours in spring season and on the contrary ~15% decrease for daylight afternoon hours in summer season. Statistically significant changes were identified for spring months (April and May, 0-6 hours and summer months (July, 12-20 hours. Increasing O3 values in the night may be associated with the absence of BVOC for ozonolysis reaction that is one of the mechanism for O3 depletion. On the other hand, the decline of daylight O3 values in summer suggests lower O3 production

  15. Major Upgrades to the AIRS Version-6 Ozone Profile Methodology

    Susskind, Joel; Blaisdell, John; Iredell, Lena


    This research is a continuation of part of what was shown at the last AIRS Science Team Meeting in the talk Improved Water Vapor and Ozone Profiles in SRT AIRS Version-6.X and the AIRS February 11, 2015 NetMeeting Further improvements in water vapor and ozone profiles compared to Version-6.AIRS Version-6 was finalized in late 2012 and is now operational. Version-6 contained many significant improvements in retrieval methodology compared to Version-5. However, Version-6 retrieval methodology used for the water vapor profile q(p) and ozone profile O3(p) retrievals is basically unchanged from Version-5, or even from Version-4. Subsequent research has made significant improvements in both water vapor and O3 profiles compared to Version-6. This talk will concentrate on O3 profile retrievals. Improvements in water vapor profile retrievals are given in a separate presentation.

  16. Tracer measurements in the tropical tropopause layer during the AMMA/SCOUT-O3 aircraft campaign

    Homan, C.D.; Volk, C. M.; A. C. Kuhn; Werner, A.; Baehr, J.; S. Viciani; A. Ulanovski; F. Ravegnani


    We present airborne in situ measurements made during the AMMA (African Monsoon Multidisciplinary Analysis)/SCOUT-O3 campaign between 31 July and 17 August 2006 on board the M55 Geophysica aircraft, based in Ouagadougou, Burkina Faso. CO2 and N2O were measured with the High Altitude Gas Analyzer (HAGAR), CO was measured with the Cryogenically Operated Laser Diode (COLD) instrument, and O3 with the Fast Ozone ANalyzer (FOZAN)....

  17. Age-related differences in pulmonary effects of acute and subchronic episodic ozone exposures in Brown Norway rats

    Ozone (O3) is known to induce adverse pulmonary and systemic health effects. Importantly, children and older persons are considered at-risk populations for O3-induced dysfunction, yet the mechanisms accounting for the age-related pulmonary responses to O3 are uncertain. In this s...

  18. Photochemical grid model implementation of VOC, NOx, and O3 source apportionment

    R. H. F. Kwok


    Full Text Available For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3 concentrations. Source based apportionment techniques implemented in photochemical grid models track sources through the physical and chemical processes important to the formation and transport of air pollutants. Photochemical model source apportionment has been used to estimate impacts of specific sources, groups of sources (sectors, sources in specific geographic areas, and stratospheric and lateral boundary inflow on O3. The implementation and application of a source apportionment technique for O3 and its precursors, nitrogen oxides (NOx and volatile organic compounds (VOC, for the Community Multiscale Air Quality (CMAQ model are described here. The Integrated Source Apportionment Method (ISAM O3 approach is a hybrid of source apportionment and source sensitivity in that O3 production is attributed to precursor sources based on O3 formation regime (e.g., for a NOx-sensitive regime, O3 is apportioned to participating NOx emissions. This implementation is illustrated by tracking multiple emissions source sectors and lateral boundary inflow. NOx, VOC, and O3 attribution to tracked sectors in the application are consistent with spatial and temporal patterns of precursor emissions. The O3 ISAM implementation is further evaluated through comparisons of apportioned ambient concentrations and deposition amounts with those derived from brute force zero-out scenarios, with correlation coefficients ranging between 0.58 and 0.99 depending on specific combination of target species and tracked precursor emissions. Low correlation coefficients occur for chemical regimes that have strong non-linearity in O3 sensitivity, which demonstrates different functionalities between source apportionment and zero-out approaches, depending on whether sources of interest are either to

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

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

  20. Enhancement Factors in Ozone Absorption Based on the Surface Renewal Model and its Application


    Based on the Danckwerts surface renewal model, a simple explicit expression of theenhancement factor in ozone absorption with a first order ozone self-decomposition and parallel secondorder ozonation reactions has been derived. The results are compared with our previous work based onthe film theory. The 2,4-dichlorophenol destruction rate by ozonation is predicted using the enhancementfactor model in this paper.

  1. Characteristics of UV-MicroO3 Reactor and Its Application to Microcystins Degradation during Surface Water Treatment

    Guangcan Zhu


    Full Text Available The UV-ozone (UV-O3 process is not widely applied in wastewater and potable water treatment partly for the relatively high cost since complicated UV radiation and ozone generating systems are utilized. The UV-microozone (UV-microO3, a new advanced process that can solve the abovementioned problems, was introduced in this study. The effects of air flux, air pressure, and air humidity on generation and concentration of O3 in UV-microO3 reactor were investigated. The utilization of this UV-microO3 reactor in microcystins (MCs degradation was also carried out. Experimental results indicated that the optimum air flux in the reactor equipped with 37 mm diameter quartz tube was determined to be 18∼25 L/h for efficient O3 generation. The air pressure and humidity in UV-microO3 reactor should be low enough in order to get optimum O3 output. Moreover, microcystin-RR, YR, and LR (MC-RR, MC-YR, and MC-LR could be degraded effectively by UV-microO3 process. The degradation of different MCs was characterized by first-order reaction kinetics. The pseudofirst-order kinetic constants for MC-RR, MC-YR, and MC-LR degradation were 0.0093, 0.0215, and 0.0286 min−1, respectively. Glucose had no influence on MC degradation through UV-microO3. The UV-microO3 process is hence recommended as a suitable advanced treatment method for dissolved MCs degradation.

  2. Modifications of Phleum pratense grass pollen allergens following artificial exposure to gaseous air pollutants (O-3, NO2, SO2)

    Rogerieux, F.; Godfrin, D.; Senechal, H.; Motta, A. C.; Marliere, M.; Peltre, G.; Lacroix, G.


    Background: Air pollution is frequently proposed as a potential cause of the increased incidence of allergy in industrialised countries. Our objective was to investigate the impact of the major gaseous air pollutants on grass pollen allergens. Methods: Timothy grass pollen was exposed to ozone (O-3)

  3. Identification of potential toxicity caused by O3 and ClO2 treatment of pharmaceuticals in wastewater

    Furuhagen, S. M.; Hörsing, Maritha; Ledin, Anna


    Chemical oxidation treatment is an effective innovative technology in wastewater treatment plants for removal of micro-pollutants in the effluent. In particular, ozonation (O3) and chlorine dioxide (ClO2) treatments are commonly used to degrade organic pollutants. By oxidation, the micro-pollutants...

  4. Aspen-associated mycorrhizal fungal production and respiration as a function of changing CO2, O3 and climatic variables

    Carrie J. Andrew; Linda T.A. van Diepen; R. Michael Miller; Erik A. Lilleskov


    The relationships of mycorrhizal fungal respiration and productivity to climate and atmospheric chemistry remain under characterized. We quantified mycorrhizal sporocarp and hyphal respiration, as well as growing season net hyphal production, under ambient and elevated carbon dioxide (CO2) and ozone (O3) in relation to...

  5. Caffeine degradation in water by gamma irradiation, ozonation and ozonation/gamma irradiation

    Torun Murat


    Full Text Available Aqueous solutions of caffeine were treated with ozone and gamma irradiation. The amounts of remaining caffeine were determined after solid phase extraction as a function of absorbed dose and ozonation time. In addition to this, some important parameters such as inorganic ions, chemical oxygen demand (COD dissolved oxygen and total acidity changes were followed. Caffeine (50 ppm is found to be completely decomposed at 3.0 kGy and 1.2 kGy doses in the absence of H2O2 and in 1.20 mM H2O2 solutions, respectively. In the case of gamma irradiation after ozonation, 50 ppm caffeine was removed at 0.2 kGy when the solution was ozonized for 100 s at a rate of 10 g O3 h-1 in 400 mL 50 ppm paracetamol solution.

  6. O3/TiO2/Al2O3处理钻井废水的试验研究%Experimental study on the treatment of drilling wastewater by O3/TiO2/Al2O3 process

    杨德敏; 袁建梅


    Improved sol-gel has been used for preparing TiO2 heterogeneous catalyst which uses Al2O3 as its carrier. Drilling wastewater COD as target degradation products,the effects of catalyst dosage,ozone concentration,pH and reaction time on COD removal by O3/TiO2/Al2O3 catalytic oxidation are investigated. The results show that comparied with O3 and O3/TiO2 treatment processes separately,the wastewater COD removing rate is greatly improved by O3/TiO2/Al2O3 process,and alkalic pH environment is good for carrying on the TiO2/Al2O3 catalytic ozonation process. Under the conditions as follows:the catalyst dosage is 3.75 g/L,ozone mass concentration 80 mg/L,and pH 9.4,and after 25 min of reaction time,the COD removing rate can reach 92.35%,wastewater COD decreases from 890 mg/L to about 68 mg/L,meeting the first class requirements of Wastewater Comprehensive Discharge Standard (GB 8978-1996).%试验采用改进的溶胶-凝胶法制备了以Al2O3为载体的TiO2多相催化剂,并以钻井废水COD为目标降解物,考察了催化剂投加量、臭氧浓度、pH和反应时间对O3/TiO2/Al2O3催化氧化去除COD的影响。结果表明:相比于单独O3O3/TiO2处理工艺,O3/TiO2/Al2O3明显地提高了对废水COD的去除率,且碱性pH环境利于TiO2/Al2O3催化臭氧化反应的进行;在催化剂投加量为3.75 g/L,臭氧质量浓度为80 mg/L,pH为9.4的条件下,反应25 min后,COD去除率可达92.35%,废水COD可从890 mg/L降至约68 mg/L,达到了《污水综合排放标准》(GB 8978-1996)的一级排放标准。

  7. Formaldehyde degradation by UV/TiO2/O3 process using continuous flow mode.

    Qi, Hong; Sun, De-Zhi; Chi, Guo-Qing


    The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g., it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84-24 mg/m3 by O3/TiO2/UV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/(m3 x min) and Langmuir adsorption coefficient K of 0.0268 m3/mg were obtained.

  8. Formaldehyde degradation by UV/TiO2/O3 process using continuous flow mode


    The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode.The effects of humidity,initial formaldehyde concentration,residence time and ozone adding amount on degradation of formaldehyde gas were investigated.The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action,e.g.,it could considerably increase decomposing of formaldehyde.The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84-24 mg/m3 by O3/TiO2/UV process.The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m3.Furthermore.the kinetics of formaldehyde degradation coefficient K of 0.0268 m3/mg were obtained.

  9. High pressure antiferrodistortive phase transition in mixed crystals of EuTiO3 and SrTiO3

    Paraskevas Parisiades


    Full Text Available We report a detailed high pressure study on Eu1−xSrxTiO3 polycrystalline samples using synchrotron x-ray diffraction. We have observed a second-order antiferrodistortive phase transition for all doping levels which corresponds to the transition that has been previously explored as a function of temperature. The analysis of the compression mechanism by calculating the lattice parameters, spontaneous strains and tilt angles of the TiO6 octahedra leads to a high pressure phase diagram for Eu1−xSrxTiO3.

  10. High pressure antiferrodistortive phase transition in mixed crystals of EuTiO3 and SrTiO3

    Parisiades, Paraskevas; Saltarelli, Francesco; Liarokapis, Efthymios; Köhler, Jürgen; Bussmann-Holder, Annette


    We report a detailed high pressure study on Eu1-xSrxTiO3 polycrystalline samples using synchrotron x-ray diffraction. We have observed a second-order antiferrodistortive phase transition for all doping levels which corresponds to the transition that has been previously explored as a function of temperature. The analysis of the compression mechanism by calculating the lattice parameters, spontaneous strains and tilt angles of the TiO6 octahedra leads to a high pressure phase diagram for Eu1-xSrxTiO3.

  11. Impact of intercontinental pollution transport on North American ozone air pollution: an HTAP phase 2 multi-model study

    Huang, Min; Carmichael, Gregory R.; Pierce, R. Bradley; Jo, Duseong S.; Park, Rokjin J.; Flemming, Johannes; Emmons, Louisa K.; Bowman, Kevin W.; Henze, Daven K.; Davila, Yanko; Sudo, Kengo; Eiof Jonson, Jan; Tronstad Lund, Marianne; Janssens-Maenhout, Greet; Dentener, Frank J.; Keating, Terry J.; Oetjen, Hilke; Payne, Vivienne H.


    the EAS anthropogenic NOx emissions matter more than the other EAS O3 precursors to the North American O3, qualitatively consistent with previous adjoint sensitivity calculations. In addition to the analyses on large spatial-temporal scales relative to the HTAP1, we also show results on subcontinental and event scales that are more relevant to the US air quality management. The EAS pollution impacts are weaker during observed O3 exceedances than on all days in most US regions except over some high-terrain western US rural/remote areas. Satellite O3 (TES, JPL-IASI, and AIRS) and carbon monoxide (TES and AIRS) products, along with surface measurements and model calculations, show that during certain episodes stratospheric O3 intrusions and the transported EAS pollution influenced O3 in the western and the eastern US differently. Free-running (i.e., without chemical data assimilation) global models underpredicted the transported background O3 during these episodes, posing difficulties for STEM to accurately simulate the surface O3 and its source contribution. Although we effectively improved the modeled O3 by incorporating satellite O3 (OMI and MLS) and evaluated the quality of the HTAP2 emission inventory with the Royal Netherlands Meteorological Institute-Ozone Monitoring Instrument (KNMI-OMI) nitrogen dioxide, using observations to evaluate and improve O3 source attribution still remains to be further explored.

  12. Reducing Uncertainty in Chemistry Climate Model Predictions of Stratospheric Ozone

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


    Chemistry climate models (CCMs) are used to predict the future evolution of stratospheric ozone as ozone-depleting substances decrease and greenhouse gases increase, cooling the stratosphere. CCM predictions exhibit many common features, but also a broad range of values for quantities such as year of ozone-return-to-1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to chlorine change from that due to climate change. We show that the sensitivity of lower atmosphere ozone to chlorine change deltaO3/deltaCly is a near linear function of partitioning of total inorganic chlorine (Cly) into its reservoirs; both Cly and its partitioning are controlled by lower atmospheric transport. CCMs with realistic transport agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035 differences in response to chlorine contribute little to the spread in CCM results as the anthropogenic contribution to Cly becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change deltaO3/deltaT due to different contributions from various ozone loss processes, each with their own temperature dependence. In the lower atmosphere, tropical ozone decreases caused by a predicted speed-up in the Brewer-Dobson circulation may or may not be balanced by middle and high latitude increases, contributing most to the spread in late 21st century predictions.

  13. Use of fluorescence spectroscopy to control ozone dosage in recirculating aquaculture systems

    Spiliotopoulou, Aikaterini; Martin, Richard; Pedersen, Lars-Flemming


    which fluorescence intensity degradation was eventually determined. Ozonation kinetic experiments showed that RAS water contains fluorescent organic matter, which is easily oxidised upon ozonation in relatively low concentrations (0–5 mg O3/L). Fluorescence spectroscopy has a high level of sensitivity......The aim of this study was to investigate the potential of fluorescence spectroscopy to be used as an ozone dosage determination tool in recirculating aquaculture systems (RASs), by studying the relationship between fluorescence intensities and dissolved organic matter (DOM) degradation by ozone......, in order to optimise ozonation treatment. Water samples from six different Danish facilities (two rearing units from a commercial trout RAS, a commercial eel RAS, a pilot RAS and two marine water aquariums) were treated with different O3 dosages (1.0–20.0 mg/L ozone) in bench-scale experiments, following...

  14. Hexagonal LuMnO3 revisited

    Aken, Bas B. van; Meetsma, Auke; Palstra, Thomas T.M.


    The crystal structure of hexagonal LuMnO3 at room temperature is isomorphous with YMnO3 and deviates in important details from early work. Mn is near the centre of its oxygen coordination environment. On the threefold axes, the apical O-Lu bonds have alternating long and short bond lengths, leading

  15. Excellent ethanol sensing properties based on Er2O3-Fe2O3 nanotubes

    刘唱白; 何滢; 王圣蕾


    In this work, pureα-Fe2O3 and Er2O3-Fe2O3 nanotubes were synthesized by a simple single-capillary electrospin-ning technology followed by calcination treatment. The morphologies and crystal structures of the as-prepared samples were characterized by scanning electron microscopy and x-ray diffraction, respectively. The gas-sensing properties of the as-prepared samples have been researched, and the result shows that the Er2O3-Fe2O3 nanotubes exhibit much better sen-sitivity to ethanol. The response value of Er2O3-Fe2O3 nanotubes to 10 ppm ethanol is 21 at the operating temperature 240◦, which is 14 times larger than that of pureα-Fe2O3 nanotubes (response value is 1.5). The ethanol sensing properties ofα-Fe2O3 nanotubes are remarkably enhanced by doping Er, and the lowest detection limit of Er2O3-Fe2O3 nanotubes is 300 ppb, to which the response value is about 2. The response and recovery times are about 4 s and 70 s to 10 ppm ethanol, respectively. In addition, the Er2O3-Fe2O3 nanotubes possess good selectivity and long-term stability.

  16. UV/O3工艺去除甲基叔丁基醚过程中BrO3-的产生与控制%Bromate formation and control in process of removing methyl tert-butyl ether by UV/O3 technology

    赵光宇; 吕锡武; 周易


    Bromate is a potential carcinogen and formed in treatment of bromide-containing water using ozone-based technologies.So,the study on bromate formation during removal of organic pollutions is necessary for applying UV/O3 process.The effects of water background,initial MTBE concentration,ozone dosage and dosing method on removal of methyl tert-butyl ether (MTBE) and formation of bromate were studied.Besides,the mechanism of action for ozone dosing method was explored.The results showed that MTBE removal rates obtained by UV/O3 process in ultrapure water and tap water were 93.5 % and 88.67%,and bromate concentration were 18.01 μg · L-1 and 12.13 μg· L-1,respectively,which were higher than the standard value of 10 μg · L-1.The promotion of initial MTBE concentration inhibited bromate formation,but longer reaction time were compulsory since MTBE concentration was required to be lower than proposed concentration of 5 μg · L-1.In this case,bromate formation was eventually enhanced.Increase of ozone dosage was favorable for MTBE removal,but caused decline of the utilization rate of ozone and the promotion of bromate formation.Comparing three ozone dosing methods in which the same ozone dosage of 5 mg · min · L-1 was applied,the highest hydroxyl radical (· OH) exposure and minimum ozone exposure were obtained in the method at ozone concentration of 0.75 mg · L-1 and reaction time of 120 min.Therefore,the concentrations of MTBE and bromate in water both met the standard values after treatment.

  17. Effect of calcium-ozone treatment on chemical and biological properties of polyethylene terephthalate.

    Rashid, Ahmed Nafis; Tsuru, Kanji; Ishikawa, Kunio


    Ozone (O3 ) treatment of polyethylene terephthalate (PET) in distilled water was performed in the presence and absence of calcium (Ca(2+) ). PET was oxidized and thus carboxylic and hydroxyl functional groups were introduced on its surface after O3 treatment, regardless of the presence or absence of Ca(2+) . In the case of O3 treatment with Ca(2+) , PET surface was modified with Ca(2+) . Ca(2+) immobilization was confirmed by X-ray photoelectron spectrometric analysis. Hydrophilicity was investigated by measuring contact angles (CA). CA of PET decreased significantly after ozonation. Surface topography of PET before and after ozone treatment was observed by scanning electron microscopy, and showed no morphological changes. In vitro studies showed enhanced rat bone marrow cell responses on the O3 -treated PET surface. Ca(2+) -O3 oxidation at 37°C for 6 h is expected to be an effective method to fabricate PET with good biocompatibility.

  18. Reactions of thiocarbamate, triazine and urea herbicides, RDX and benzenes on EPA Contaminant Candidate List with ozone and with hydroxyl radicals

    Second-order rate constants of the direct ozone reactions (kO3,M) and the indirect OH radical reactions (kOH,M) for nine chemicals on the US EPA’s Drinking Water Contaminant Candidate List (CCL) were studied during the ozonation and ozone/hydrogen peroxide a...

  19. Reactions of thiocarbamate, triazine and urea herbicides, RDX and benzenes on EPA Contaminant Candidate List with ozone and with hydroxyl radicals

    Second-order rate constants of the direct ozone reactions (kO3,M) and the indirect OH radical reactions (kOH,M) for nine chemicals on the US EPA’s Drinking Water Contaminant Candidate List (CCL) were studied during the ozonation and ozone/hydrogen peroxide a...

  20. Kinetic analysis of Legionella inactivation using ozone in wastewater.

    Li, Jun; Li, Kunquan; Zhou, Yan; Li, Xuebin; Tao, Tao


    Legionella inactivation using ozone was studied in wastewater using kinetic analysis and modeling. The experimental results indicate that the relationship between the ozone concentration, germ concentration, and chemical oxygen demand (COD) can be used to predict variations in germ and COD concentrations. The ozone reaction with COD and inactivation of Legionella occurred simultaneously, but the reaction with COD likely occurred at a higher rate than the inactivation, as COD is more easily oxidized by ozone than Legionella. Higher initial COD concentrations resulted in a lower inactivation rate and higher lnN/N0. Higher temperature led to a higher inactivation efficiency. The relationship of the initial O3 concentration and Legionella inactivation rate was not linear, and thus, the Ct value required for a 99.99% reduction was not constant. The initial O3 concentration was more important than the contact time, and a reduction of the initial O3 concentration could not be compensated by increasing the contact time. The Ct values were compared over a narrow range of initial concentrations; the Ct values could only be contrasted when the initial O3 concentrations were very similar. A higher initial O3 concentration led to a higher inflection point value for the lnN/N0 vs C0t curve. Energy consumption using a plasma corona was lower than when using boron-doped diamond electrodes.

  1. Low Ozone over Europe Doesn't Mean the Sky Is Falling, Its Actually Rising

    Strahan, Susan; Newman, Paul; Steenrod, Stephen


    Data Sources: NASA Aura Microwave Limb Sounder (MLS) (O3 profiles and columns), NASA Global Modeling Initiative (GMI) Chemistry and Transport Model (calculated O3depletion), and MERRA Tropopause Heights. Technical Description of Figures: The left graphics show MLS northern hemisphere stratospheric column ozone on Feb. 1, 2016. Very low columns are seen over the UK and Europe (<225 DU, inside dashed circle). The lower graphic shows the GMI-calculated O3 depletion. It's very small, suggesting the low O3 does not indicate significant depletion. The right graphics show how the high tropopause height in this region explains the observed low ozone. The lower panel shows that the high tropopause on Feb. 1 lifts the O3 profile compared to a typical profile found earlier in winter. This motion lifts the profile to lower pressures thus reducing the total column. The GMI Model shows only 4 Dobson Units (DU) of O3 depletion even though the column is more than 100 DU lower than one month earlier. Scientific significant and societal relevance: To quantitatively understand anthropogenic impacts to the stratospheric ozone layer, we must be able to distinguish between low ozone caused by ozone depleting substances and that caused by natural dynamical variability in the atmosphere. Observations and realistic simulations of atmospheric composition are both required in order to separate natural and anthropogenic ozone variability.

  2. Study of ozone “weekend effect” in Shanghai


    Analysis of observed ozone data in 2006 from five monitoring sites (Xujiahui, Chongming, Baoshan, Pudong, Jinshan) in Shanghai reveals that ozoneO3) concentrations in Xujiahui are higher at week-ends than those on weekdays, despite the fact that emissions of ozone precursor substances, such as oxides of nitrogen (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs) are lower at weekends than those on weekdays. The possible chemical cause of ozone "weekend effect" is that NO2/NO ratio increases at weekends by 25.61% compared with those on weekdays. In addition, because of an average 12.13% reduction in NOx (NO + NO2) in the early morning (05:00-09:00) at weekends compared with that on weekdays, the ozone inhibition period ends 0.5 h earlier at weekends resulting in the longer duration of ozone accumulation and the higher ozone production rate. The rate of ozone production is a function of VOCs and NOx in the atmosphere. VOCs/NOx ratio in Xujiahui is 4.55 at weekends, and 4.37 on weekdays, belonging to the "NOx-limited". The increasing VOCs/NOx ratio at weekends leads to ozone enhancement from 73 ppbv to 80 ppbv, which are consistent with ozone "weekend effect" in Xujiahui. Furthermore, combining with MICAPS cloud amount data, the fact that ozone "weekend effect" in Xujiahui weakens gradually along with the increasing of cloud amount indicates that ozone photochemical production leads to ozone "weekend effect" in Xujiahui of Shanghai.

  3. Democratic Mass Matrices from Broken $O(3)_{L} \\times O(3)_{R}$ Flavor Symmetry

    Tanimoto, M; Yanagida, T


    We impose $O(3)_L\\times O(3)_R$ flavor symmetry in the supersymmetric standard model. Three lepton doublets $\\ell_i$ transform as an $O(3)_L$ triplet and three charged leptons $\\bar e_i$ as an $O(3)_R$ triplet, while Higgs doublets $H$ and $\\bar H$ are $O(3)_L\\times O(3)_R$ singlets. We discuss a flavor $O(3)_L\\times O(3)_R$ breaking mechanism that leads to "successful" phenomenological mass matrices, so-called "democratic" ones, in which the large degenerate masses of order $0.1\\eV$ which may be accesible to future double that it is well consistent with the observed quark mass hierarchies and the CKM matrix elements.

  4. Preparation and Characterization of Fe2O3/Al2O3 Nano-composites


    Al2O3/Fe2O3 nano-composites were prepared by sol-gel route. The effect of Fe2O3 content on the structure, grain size and characterization of the composite were investigated through X-ray diffraction and M(o)ssbauer spectrum. The X-ray diffraction results show that Al2O3/Fe2O3 nano-composites with the Fe2O3, content of 40 wt% can be obtained after heat-treated at 900℃. The M(o)ssbauer effect results show that all samples exhibit clear super-paramagnetic phenomenon. Particles grow and defects reduce with the increasing of Fe2O3 conteni and some α-Fe2O3 stay magnetic order.

  5. Surface ozone and carbon monoxide levels observed at Oki, Japan: regional air pollution trends in East Asia.

    Sikder, Helena Akhter; Suthawaree, Jeeranut; Kato, Shungo; Kajii, Yoshizumi


    Simultaneous ground-based measurements of ozone and carbon monoxide were performed at Oki, Japan, from January 2001 to September 2002 in order to investigate the O(3) and CO characteristics and their distributions. The observations revealed that O(3) and CO concentrations were maximum in springtime and minimum in the summer. The monthly averaged concentrations of O(3) and CO were 60 and 234 ppb in spring and 23 and 106 ppb in summer, respectively. Based on direction, 5-day isentropic backward trajectory analysis was carried out to determine the transport path of air masses, preceding their arrival at Oki. Comparison between classified results from present work and results from the year 1994-1996 was carried out. The O(3) and CO concentration results of classified air masses in our analysis show similar concentration trends to previous findings; highest in the WNW/W, lowest in N/NE and medium levels in NW. Moreover, O(3) levels are higher and CO levels are lower in the present study in all categories. Copyright © 2010 Elsevier Ltd. All rights reserved.


    Burton, Andrew J. [Michigan Technological University; Zak, Donald R. [University of Michigan; Kubiske, Mark E. [USDA Forest Service; Pregitzer, Kurt S. [University of Idaho


    photosynthesis increased with elevated CO2 and tended to decrease with elevated O3, compared to the control. In contrast to aspen and birch, maple photosynthesis was not enhanced by elevated CO2. Elevated O3 did not cause significant reductions in maximum photosynthesis in birch or maple. In addition, photosynthesis in ozone sensitive clones was affected to a much greater degree than that in ozone tolerant aspen clones. Treatment effects on photosynthesis contributed to CO2 stimulation of aboveground and belowground growth that was species and genotype dependent, with birch and aspen being most responsive and maple being least responsive. The positive effects of elevated CO2 on net primary productivity NPP were sustained through the end of the experiment, but negative effects of elevated O3 on NPP had dissipated during the final three years of treatments. The declining response to O3 over time resulted from the compensatory growth of O3-tolerant genotypes and species as the growth of O3-sensitive individuals declined over time. Cumulative NPP over the entire experiment was 39% greater under elevated CO2 and 10% lower under elevated O3. Enhanced NPP under elevated CO2 was sustained by greater root exploration of soil for growth-limiting N, as well as more rapid rates of litter decomposition and microbial N release during decay. Results from Aspen FACE clearly indicate that plants growing under elevated carbon dioxide, regardless of community type or ozone level, obtained significantly greater amounts of soil N. These results indicate that greater plant growth under elevated carbon dioxide has not led to “progressive N limitation”. If similar forests growing throughout northeastern North America respond in the same manner, then enhanced forest NPP under elevated CO2 may be sustained for a longer duration than previously thought, and the negative effect of elevated O3 may be diminished by compensatory growth of O3-tolerant plants as they begin to dominate forest communities. By

  7. Tropospheric Ozone and Photochemical Smog

    Sillman, S.


    The question of air quality in polluted regions represents one of the issues of geochemistry with direct implications for human well-being. Human health and well-being, along with the well-being of plants, animals, and agricultural crops, are dependent on the quality of air we breathe. Since the start of the industrial era, air quality has become a matter of major importance, especially in large cities or urbanized regions with heavy automobile traffic and industrial activity.Concern over air quality existed as far back as the 1600s. Originally, polluted air in cities resulted from the burning of wood or coal, largely as a source of heat. The industrial revolution in England saw a great increase in the use of coal in rapidly growing cities, both for industrial use and domestic heating. London suffered from devastating pollution events during the late 1800s and early 1900s, with thousands of excess deaths attributed to air pollution (Brimblecombe, 1987). With increasing use of coal, other instances also occurred in continental Europe and the USA. These events were caused by directly emitted pollutants (primary pollutants), including sulfur dioxide (SO2), carbon monoxide (CO), and particulates. They were especially acute in cities with northerly locations during fall and winter when sunlight is at a minimum. These original pollution events gave rise to the term "smog" (a combination of smoke and fog). Events of this type have become much less severe since the 1950s in Western Europe and the US, as natural gas replaced coal as the primary source of home heating, industrial smokestacks were designed to emit at higher altitudes (where dispersion is more rapid), and industries were required to install pollution control equipment.Beginning in the 1950s, a new type of pollution, photochemical smog, became a major concern. Photochemical smog consists of ozone (O3) and other closely related species ("secondary pollutants") that are produced photochemically from directly

  8. Ozone Decomposition on the Surface of Metal Oxide Catalyst

    Batakliev Todor Todorov


    Full Text Available The catalytic decomposition of ozone to molecular oxygen over catalytic mixture containing manganese, copper and nickel oxides was investigated in the present work. The catalytic activity was evaluated on the basis of the decomposition coefficient which is proportional to ozone decomposition rate, and it has been already used in other studies for catalytic activity estimation. The reaction was studied in the presence of thermally modified catalytic samples operating at different temperatures and ozone flow rates. The catalyst changes were followed by kinetic methods, surface measurements, temperature programmed reduction and IR-spectroscopy. The phase composition of the metal oxide catalyst was determined by X-ray diffraction. The catalyst mixture has shown high activity in ozone decomposition at wet and dry O3/O2 gas mixtures. The mechanism of catalytic ozone degradation was suggested.

  9. Forecasting and analyzing high O3 time series in educational area through an improved chaotic approach

    Hamid, Nor Zila Abd; Adenan, Nur Hamiza; Noorani, Mohd Salmi Md


    Forecasting and analyzing the ozone (O3) concentration time series is important because the pollutant is harmful to health. This study is a pilot study for forecasting and analyzing the O3 time series in one of Malaysian educational area namely Shah Alam using chaotic approach. Through this approach, the observed hourly scalar time series is reconstructed into a multi-dimensional phase space, which is then used to forecast the future time series through the local linear approximation method. The main purpose is to forecast the high O3 concentrations. The original method performed poorly but the improved method addressed the weakness thereby enabling the high concentrations to be successfully forecast. The correlation coefficient between the observed and forecasted time series through the improved method is 0.9159 and both the mean absolute error and root mean squared error are low. Thus, the improved method is advantageous. The time series analysis by means of the phase space plot and Cao method identified the presence of low-dimensional chaotic dynamics in the observed O3 time series. Results showed that at least seven factors affect the studied O3 time series, which is consistent with the listed factors from the diurnal variations investigation and the sensitivity analysis from past studies. In conclusion, chaotic approach has been successfully forecast and analyzes the O3 time series in educational area of Shah Alam. These findings are expected to help stakeholders such as Ministry of Education and Department of Environment in having a better air pollution management.

  10. Tropospheric Ozone as a Short-lived Chemical Climate Forcer

    Pickering, Kenneth E.


    Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

  11. An Investigation of Widespread Ozone Damage to the Soybean Crop in the Upper Midwest Determined From Ground-Based and Satellite Measurements

    Fishman, Jack; Creilson, John K.; Parker, Peter A.; Ainsworth, Elizabeth A.; Vining, G. Geoffrey; Szarka, John; Booker, Fitzgerald L.; Xu, Xiaojing


    Elevated concentrations of ground-level ozone (O3) are frequently measured over farmland regions in many parts of the world. While numerous experimental studies show that O3 can significantly decrease crop productivity, independent verifications of yield losses at current ambient O3 concentrations in rural locations are sparse. In this study, soybean crop yield data during a 5-year period over the Midwest of the United States were combined with ground and satellite O3 measurements to provide evidence that yield losses on the order of 10% could be estimated through the use of a multiple linear regression model. Yield loss trends based on both conventional ground-based instrumentation and satellite-derived tropospheric O3 measurements were statistically significant and were consistent with results obtained from open-top chamber experiments and an open-air experimental facility (SoyFACE, Soybean Free Air Concentration Enrichment) in central Illinois. Our analysis suggests that such losses are a relatively new phenomenon due to the increase in background tropospheric O3 levels over recent decades. Extrapolation of these findings supports previous studies that estimate the global economic loss to the farming community of more than $10 billion annually.

  12. Study on the improvement of biodegradability and biological toxicity of pesticide wastewater by ultrasonic-ozone process%US/O3工艺改善农药废水可生化性和生物毒性的效能

    熊正龙; 刘爱翠; 刘国伟; 孙德智


    采用超声/臭氧(US/O3)工艺处理农药废水,废水BOD5/COD由0.03提高至0.55,EC50从11%增至52%,生物毒性降低78.85%.在一定范围内,随反应时间的增加和初始pH的升高,废水可生化性不断提高,生物毒性显著降低,但当初始pH大于9、反应时间超过120 min时,废水可生化性出现下降趋势;当初始pH大于11、反应时间超过120 min时废水生物毒性出现升高趋势.

  13. Garnet-Perovskite transformation in CaGeO3

    Ono, S.


    The phase transitions and physical properties of the garnet and the perovskite structure at high P-T conditions have attracted attention to understand the dynamics of the Earth's interior because major compositions (MgSiO3 or CaSiO3) have these structures in the Earth's mantle. It is known that some ABO3 compounds are excellent analogues of MgSiO3 or CaSiO3. Calcium germinate (CaGeO3) exhibits a sequence of phase transitions from a pyroxenoid to a tetragonal garnet phase, and subsequently to an orthorhombic perovskite phase. The phase boundaries in CaGeO3 have been also used as a pressure calibration point at high temperatures in high-pressure experiments, such as for SiO2 and Mg2SiO4. Therefore, the precise phase boundary of CaGeO3 needs to be determined. The transition pressure of CaGeO3 has been investigated in static high-pressure experiments using quench [1] and in situ methods [2]. According to previous high-pressure experiments, the transition pressure is ~6 GP and this boundary had a negative slope. In contrast, Ross et al. [1] also estimated the value of dP/dT slope of this transition using calorimetry data, and calculated the slope to be 2-3 times more negative than the value determined from high-pressure experiments. Therefore, we reinvestigated the dP/dT slope of garnet-perovskite transition in CaGeO3 using the high-pressure experiments. In this study, the use of a multi-anvil high-pressure system combined with a synchrotron radiation source made it possible to acquire precise data from samples under high-pressure and high-temperature conditions [3]. After reaching the required pressure and temperature, we performed in situ measurements using the synchrotron X-rays. The duration of heating was 0.5-2.0 hours. At the end of the experimental runs, the sample was quenched by cutting off the electrical power. This heating procedure was the same as that used in typical quench experiments. We performed approximately 30 experimental runs, and the boundary

  14. Convective Signatures in Ozone Profiles: Guidance for Cloud Models

    Stone, J. B.; Thompson, A. M.; Miller, S. K.; Witte, J. C.; Pickering, K. E.; Tao, W. K.


    Ozone throughout the free troposphere is a tracer for convection, stratospheric exchange and pollution. Convective influences are typically manifested in two ways: (1) redistribution of ozone from the boundary-layer to free troposphere. In unpolluted regions, this usually means decreasing ozone in the upper troposphere (UT) or UT/LS (upper troposphere-lower stratosphere). Over polluted regions, the opposite may occur. (2) enhancing O3 precursors (NO, CO, hydrocarbons) in the free troposphere, through redistribution, or in the case of lightning, through direct production of NO, adds to photochemical ozone formation. Since about 1990 we have studied ozone dynamics and photochemistry with cloud-resolving (CRM) and larger-scale models. Aircraft profiles of O3, ozone precursors (NO, CO, hydrocarbons) and photochemically related constituents guide model input and are used to evaluate model output. Recently, we have used a semi-empirical approach ("lamina-layering," after Pierce and Grant [1998]) to identifying convective impacts on ozone profiles taken with soundings. The latter are measured by ozonesondes that are flown with radiosondes, to collect PTU data. The advantage of ozonesondes is consistent vertical sampling of ozone into the UT/LS with 5- 25 m resolution, and regular frequency at stations where they are launched. Examples of convective influence in ozone profiles - case studies and climatology at selected locations - will be shown for mid-latitudes and tropics. In mid-latitudes convective ozone budgets are compared to influences of stratospheric exchange and pollution. In the tropics, convective impacts reflect El Nino, the MJO and possible trends in a cooling UT/LS.

  15. Anomalous high mobility in LaAlO3/SrTiO3 nanowires.

    Irvin, Patrick; Veazey, Joshua P; Cheng, Guanglei; Lu, Shicheng; Bark, Chung-Wung; Ryu, Sangwoo; Eom, Chang-Beom; Levy, Jeremy


    Nanoscale control of the metal-insulator transition at the interface between LaAlO(3) and SrTiO(3) provides a pathway for reconfigurable, oxide-based nanoelectronics. Four-terminal transport measurements of LaAlO(3)/SrTiO(3) nanowires at room temperature (T = 300 K) reveal an equivalent 2D Hall mobility greatly surpassing that of bulk SrTiO(3) and approaching that of n-type Si nanowires of comparable dimensions. This large enhancement of mobility is relevant for room-temperature device applications.

  16. Relation between structural instabilities in EuTiO3 and SrTiO3

    Bussmann-Holder, A.; Köhler, J.; Kremer, R. K.; Law, J. M.


    Specific heat measurements and theoretical calculations reveal an intimate analogy between EuTiO3 and SrTiO3. For EuTiO3, a hitherto unknown specific heat anomaly is discovered at temperatures TA= 282(1)K, which is analogous to the well-known specific heat anomaly of SrTiO3 at the temperature TA= 105K caused by an antiferrodistortive transition. Because the zone center soft phonon mode observed in both systems can be modeled with the same parameters, we ascribe the new 282(1)K instability of EuTiO3 to an antiferrodistortive phase transition. The higher transition temperature of EuTiO3 as compared to SrTiO3 results from spin-phonon coupling.

  17. Transport in ferromagnetic GdTiO3/SrTiO3 heterostructures

    Moetakef, Pouya; Zhang, Jack Y.; Kozhanov, Alexander; Jalan, Bharat; Seshadri, Ram; Allen, S. James; Stemmer, Susanne


    Epitaxial GdTiO3/SrTiO3 structures with different SrTiO3 layer thicknesses are grown on (001) (LaAlO3)0.3(Sr2AlTaO6)0.7 substrate surfaces by hybrid molecular beam epitaxy. It is shown that the formation of the pyrochlore (Gd2Ti2O7) phase can be avoided if GdTiO3 is grown by shuttered growth, supplying alternating monolayer doses of Gd and of the metalorganic precursor that supplies both Ti and O. Phase-pure GdTiO3 films grown by this approach exhibit magnetic ordering with a Curie temperature of 30 K. The electrical transport characteristics can be understood as being dominated by a conductive interface layer within the SrTiO3.

  18. SUMO: solar ultraviolet monitor and ozone nanosatellite for spectral irradiance, ozone and Earth radiative budget simultaneous evaluation

    Damé, Luc

    SUMO is an innovative proof-of-concept nano-satellite which aims to measure on the same platform the different components of the Earth radiation budget, the solar energy input and the energy reemitted at the top of the Earth atmosphere, with a particular focus on the UV part of the spectrum and on the ozone layer, which are the most sensitive to the solar variability. The far UV (FUV) is the only wavelength band with energy absorbed in the high atmosphere (stratosphere), in the ozone (Herzberg continuum, 200-220 nm) and oxygen bands, and its high variability is most probably at the origin of a climate influence (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and tropopause regions). Recent measurements at the time of the last solar minimum suggest that variations in the UV may be larger than previously assumed what implies a very different response in both stratospheric ozone and temperature. A simultaneous observation of the incoming FUV and of the ozone (O _{3}) production, would bring an invaluable information on this process of solar-climat forcing. Space instruments have already measured the different components of the Earth radiative budget but this is, to our knowledge, the first time that all instruments are operated on the same platform. This characteristic guarantees by itself obtaining original scientific results. SUMO is a 10x10x30 cm (3) nanosatellite (``3U"), the payload occupying ``1U", i.e. a cube of 10x10x10 cm (3) for 1 kg and 1 W of power. Orbit is polar since a further challenge in understanding the relation between solar UV variability and stratospheric ozone on arctic and antarctic regions. SUMO definition has been completed (platform and payload assembly integration and tests are possible in 24 months) and it is now intended to be proposed to CNES for a flight in 2017. Mission is expected to last up to 1 year. Follow-up is 2 fold: on

  19. Effects of UV/Ag-TiO2/O3 advanced oxidation on unicellular green alga Dunaliella salina: Implications for removal of invasive species from ballast water

    Donghai Wu; Hong You; Jiaxuan Du; Chuan Chen; Darui Jin


    The UV/Ag-TiO2/O3 process was investigated for ballast water treatment using Dunaliella salina as an indicator.Inactivation curves were obtained, and the toxicity of effluent was determined.Compared with individual unit processes using ozone or UV/Ag-TiO2, the inactivation efficiency of D.salina by the combined UV/Ag-TiO2/O3 process was enhanced.The presence of ozone caused an immediate decrease in chlorophyll a (chi-a) concentration.Inactivation efficiency and chl-a removal efficiency were positively correlated with ozone dose and ultraviolet intensity.The initial total residual oxidant (TRO) concentration of effluent increased with increasing ozone dose, and persistence of TRO resulted in an extended period of toxicity.The results suggest that UV/Ag-Ti02/03 has potential for ballast water treatment.

  20. Ozone dynamics in a Mediterranean Holm oak forest: comparison among transition periods characterized by different amounts of precipitation

    Flavia Savi; Silvano Fares


    Tropospheric ozone (O3) is one of the most toxic compounds for plants in the atmosphere. The large amount of anthropogenic O3 precursors in the urban areas promote O3 formation, thus making Mediterranean forests located in periurban areas particularly vulnerable to this pollutant. O3 flux measurements have been carried out using the Eddy Covariance technique over a Holm oak forest located 25 Km from Rome downtown, inside the Presidential Estate of Castelporziano (Italy).Two transition periods...

  1. Comparative transcriptomics implicates glutathione as a key regulator of ozone tolerance in legume crops

    In the past 100 years, tropospheric ozone concentrations [O3] have more than doubled in response to industrialization. Models indicate that [O3] will continue to rise another 25% by the year 2050, thus exacerbating the strain on agriculture to provide food at a time of rapid population growth. Here,...


    Epidemiological, in vitro and animal studies suggest that dietary antioxidants can modulate the cellular and physiologic effects of ozone (O3) inhalation in humans. To determine whether antioxidants can influence human susceptibility to O3-induced changes in lung function and a...

  3. Activated Sludge Ozonation to Reduce Sludge Production in MBR

    HE Sheng-bing; XUE Gang; WANG Bao-zhen


    The total experimental period was divided into two stages.At the first stage, a series of batch studies were carried out to get an understanding of the effect of ozonation on sludge properties. At the following stages, three MBRs with different amounts of activated sludge to be ozonated were run in parallel for a long period to evaluate the influence of sludge ozonation on sludge yield and permeate quality.Through batch study, it was found that ozone could disrupt the cell walls and caused the release of plasm from the cells,then the amounts of soluble organics in the solution increased with ozonation time. With the rise of soluble organics, the amount of soluble organics to be mineralized increased as well, which wonld reduce the soluble organics content. For the counteraction between these two aspects, a pseudo-balance could be achieved, and soluble organics would vary in a limited range. Sludge ozonation also increased the contents of nitrogen and phosphorus in the solution. In addition, ozonation was effective in improving sludge settling property. On the basis of batch study, a suitable ozone dosage of 0.16 kgO3/kgMLSS wasdetermined. Three systems were run in parallel for a total period of 39 days, it was demonstrated that a part of activated sludge ozonation could reduce sludge production significantly, and biological performance of mineralization and nitrification would not be inhibited due to sludge ozonation. Experimental results proved that the combination of ozonation unit with MBR unit could achieve an excellent quality of permeate as well as a small quantity of sludge production, and economic analysis indicated that an additional ozonation operating cost for treatment of both wastewater and sludge was only 0.096Yuan (US $0.011,5)/m3 wastewater.

  4. Reclaimed water quality during simulated ozone-managed aquifer recharge hybrid

    Yoon, Min


    A synergistic hybrid of two treatment processes, managed aquifer recharge (MAR) combined with ozonation, was proposed for wastewater reclamation and water reuse applications. Batch reactor and soil-column experiments were performed to evaluate reclaimed water quality using various chemical and bacterial analyses. The ozone process was optimized at low ozone dose (0.5 mg O3/mg DOC) based on the control of N-nitrosodimethylamine (<5 ng L-1) and bromate (<10 μg L-1), and applied prior to (i.e., O3-MAR) and after MAR (i.e., MAR-O3). This work demonstrates that effluent organic matter (EfOM) and trace organic contaminants (TOrCs) are effectively removed during the hybrid process of MAR combined ozonation, compared to MAR only. Based on fluorescence excitation-emission matrices analyses, both MAR and ozonation reduce soluble microbial (protein-like) products while only ozonation contributes in reducing humic and fulvic substances. Even at low ozone dose of 0.5 mg O3/mg DOC, the O3-MAR hybrid significantly reduced UV absorbance by ≥2 m-1, BDOC by ≥64 %, and total (Σ) TOrC concentrations by ≥70 % in the effluent water quality. However, no significant improvement (<10 %) in the removal of Σ16 TOrC concentrations was observed for the increased ozone dose at 1.0 mg O3/mg DOC during MAR combined ozonation processes. Overall, O3-MAR was effective by 10-30 % in treating effluent water than MAR based on DOC, UV254 nm EfOM, TOrC and bacterial analyses. In addition, MAR-O3 was better than O3-MAR for the reduction of fluorescence (close MQ), TOrCs (≥74 %) and total bacteria cell concentrations (>3 log reduction). Therefore, implementing MAR prior to ozonation appears to remove the bio-amenable compounds that react rapidly with ozone, thereby reducing oxidant demand and treatment efficiency. © 2014 Springer-Verlag Berlin Heidelberg.

  5. Kinetics of O3 destruction by ClO and BrO within the Antarctic vortex - An analysis based on in situ ER-2 data

    Anderson, J. G.; Brune, W. H.; Lloyd, S. A.; Toohey, D. W.; Sander, S. P.; Starr, W. L.; Loewenstein, M.; Podolske, J. R.


    The kinetics of ozone destruction within the Antarctic polar vortex are studied via simultaneous in situ observations of ClO, BrO, O3, N2O, pressure, and temperature. It is found that the chlorine dimer mechanism rate, limited by the reaction ClO + ClO + M yields ClOOCl + M, contributes the most to the integrated rate of ozone destruction within the vortex on isentropic surfaces between altitudes of 14 and 18.3 km.

  6. Formation potentials of bromate and brominated disinfection by-products in bromide-containing water by ozonation.

    Lin, Tao; Wu, Shouke; Chen, Wei


    The ozonation involved in drinking water treatment raises issues of water quality security when the raw water contains bromide (Br(-)). Br(-) ions may be converted to bromate (BrO3 (-)) during ozonation and some brominated disinfection by-products (Br-DBPs) in the following chlorination. In this study, the effects of ozone (O3) dosage, contact time, pH, and Br(-) and ammonia (NH3-N) concentrations on the formation of BrO3 (-) and Br-DBPs have been investigated. The results show that decreasing the initial Br(-) concentration is an effective means of controlling the formation of BrO3 (-). When the concentration of Br(-) was lower than 100 μg/L, by keeping the ratio of O3 dosage to dissolved organic carbon (DOC) concentration at less than 1, BrO3 (-) production was effectively suppressed. The concentration of BrO3 (-) steadily increased with increasing O3 dosage at high Br(-) concentration (>900 μg/L). Additionally, a longer ozonation time increased the concentrations of BrO3 (-) and total organic bromine (TOBr), while it had less impact on the formation potentials of brominated trihalomethanes (Br-THMFP) and haloacetic acids (Br-HAAFP). Higher pH value and the presence of ammonia may lead to an increase in the formation potential of BrO3 (-) and Br-DBPs.

  7. Postperovskite phase equilibria in the MgSiO3-Al2O3 system.

    Tsuchiya, Jun; Tsuchiya, Taku


    We investigate high-P,T phase equilibria of the MgSiO(3)-Al(2)O(3) system by means of the density functional ab initio computation methods with multiconfiguration sampling. Being different from earlier studies based on the static substitution properties with no consideration of Rh(2)O(3)(II) phase, present calculations demonstrate that (i) dissolving Al(2)O(3) tends to decrease the postperovskite transition pressure of MgSiO(3) but the effect is not significant ( approximately -0.2 GPa/mol% Al(2)O(3)); (ii) Al(2)O(3) produces the narrow perovskite+postperovskite coexisting P,T area (approximately 1 GPa) for the pyrolitic concentration (x(Al2O3) approximately 6 mol%), which is sufficiently responsible to the deep-mantle D'' seismic discontinuity; (iii) the transition would be smeared (approximately 4 GPa) for the basaltic Al-rich composition (x(Al2O3) approximately 20 mol%), which is still seismically visible unless iron has significant effects; and last (iv) the perovskite structure spontaneously changes to the Rh(2)O(3)(II) with increasing the Al concentration involving small displacements of the Mg-site cations.

  8. Photocatalytic properties of KBiO3 and LiBiO3 with tunnel structures

    Rajalakshmi Ramachandran; M Sathiya; K Ramesha; A S Prakash; Giridhar Madras; A K Shukla


    In the present study, KBiO3 is synthesized by a standard oxidation technique while LiBiO3 is prepared by hydrothermal method. The synthesized catalysts are characterized by X-ray diffraction (XRD), Scanning ElectronMicroscopy (SEM), BET surface area analysis and Diffuse Reflectance Spectroscopy (DRS). The XRD patterns suggest that KBiO3 crystallizes in the cubic structure while LiBiO3 crystallizes in orthorhombic structure and both of these adopt the tunnel structure. The SEM images reveal micron size polyhedral shaped KBiO3 particles and rod-like or prismatic shape particles for LiBiO3. The band gap is calculated from the diffuse reflectance spectrum and is found to be 2.1 eV and 1.8 eV for KBiO3 and LiBiO3, respectively. The band gap and the crystal structure data suggest that these materials can be used as photocatalysts. The photocatalytic activity of KBiO3 and LiBiO3 are evaluated for the degradation of anionic and cationic dyes, respectively, under UV and solar radiations.

  9. Pressureless reactive sintering mechanism of nanocrystalline Bi2O3-Y2O3 solid electrolyte


    The nanocrystalline Bi2O3-Y2O3 solid electrolyte material was synthesized by pressureless reactive sintering process with Bi2O3 and Y2O3 nano mixed powder as raw materials, which was prepared by a chemical coprecipitation process. The study on the behavior of nano δ-Bi2O3 formation and its grain growth showed that the solid solution reaction of Y2O3 and β-Bi2O3 to form δ-Bi2O3occurs mainly in the initial stage of sintering process, and nano δ-Bi2O3 crystal grains grow approximately following the rule of paracurve ((D-D0)2=K.t) during sintering process. After sintered at 600℃ for 2 h, the samples could reach above 96% in relative density and have dense microstructure with few remaining pores, the δ-Bi2O3 grains are less than 100 nm in size.

  10. Highlights from a Decade of OMI-TOMS Total Ozone Observations on EOS Aura

    Haffner, David P.; Bhartia, Pawan K.; McPeters, Richard D.; Joiner, Joanna; Ziemke, Jerald R.; Vassilkov, Alexander; Labow, Gordon J.; Chiou, Er-Woon


    Total ozone measurements from OMI have been instrumental in meeting Aura science objectives. In the last decade, OMI has extended the length of the TOMS total ozone record to over 35 years to monitor stratospheric ozone recovery. OMI-TOMS total ozone measurements have also been combined synergistically with measurements from other Aura instruments and MLS in particular, which provides vertically resolved information that complements the total O3 mapping capability of OMI. With this combined approach, the EOS Aura platform has produced more accurate and detailed measurements of tropospheric ozone. This has led in turn to greater understanding of the sources and transport of tropospheric ozone as well as its radiative forcing effect. The combined use of OMI and MLS data was also vital to the analysis of the severe Arctic ozone depletion event of 2011. The quality of OMI-TOMS total O3 data used in these studies is the result of several factors: a mature and well-validated algorithm, the striking stability of the OMI instrument, and OMI's hyperspectral capabilities used to derive cloud pressures. The latter has changed how we think about the effects of clouds on total ozone retrievals. We will discuss the evolution of the operational V8.5 algorithm and provide an overview and motivation for V9. After reviewing results and developments of the past decade, we finally highlight how ozone observations from EOS Aura are playing an important role in new ozone mapping missions.

  11. Stabilisation of Fe2O3-rich Perovskite Nanophase in Epitaxial Rare-earth Doped BiFeO3 Films.

    Zhang, Huairuo; Reaney, Ian M; Marincel, Daniel M; Trolier-McKinstry, Susan; Ramasse, Quentin M; MacLaren, Ian; Findlay, Scott D; Fraleigh, Robert D; Ross, Ian M; Hu, Shunbo; Ren, Wei; Rainforth, W Mark


    Researchers have demonstrated that BiFeO3 exhibits ferroelectric hysteresis but none have shown a strong ferromagnetic response in either bulk or thin film without significant structural or compositional modification. When remanent magnetisations are observed in BiFeO3 based thin films, iron oxide second phases are often detected. Using aberration-corrected scanning transmission electron microscopy, atomic resolution electron energy loss spectrum-mapping and quantitative energy dispersive X-ray spectroscopy analysis, we reveal the existence of a new Fe2O3-rich perovskite nanophase, with an approximate formula (Fe0.6Bi0.25Nd0.15)(3+) Fe(3+)O3, formed within epitaxial Ti and Nd doped BiFeO3 perovskite films grown by pulsed laser deposition. The incorporation of Nd and Bi ions on the A-site and coherent growth with the matrix stabilise the Fe2O3-rich perovskite phase and preliminary density functional theory calculations suggest that it should have a ferrimagnetic response. Perovskite-structured Fe2O3 has been reported previously but never conclusively proven when fabricated at high-pressure high-temperature. This work suggests the incorporation of large A-site species may help stabilise perovskite-structured Fe2O3. This finding is therefore significant not only to the thin film but also to the high-pressure community.

  12. Interaction Between Ambient Particles and Ozone and Its Effect on Daily Mortality


    Objective To examine the effect of particulate matter (PM) less than 10 microns in diameter (PM10) and ozone (O3) on daily mortality in Shanghai, China. Methods A generalized additive model with penalized spline function was used to observe the acute effect of PM10 and O3 on daily mortality. Results Higher PMt0 significantly increased the effect of O3 on total mortality,and O3 also increased the effect of PM10 although the estimated increment was statistically insignificant. Conclusion Our findings provide further evidence for the effect of PM10 and O3 on daily mortality.

  13. Removal of disinfection by-product precursors with ozone-UV advanced oxidation process.

    Chin, A; Bérubé, P R


    The efficacy of using ozone (O3), ultraviolet irradiation (UV) and the combined O3-UV advanced oxidation process (AOP) to remove 2 classes of disinfection by-product (DBP) precursors from raw surface water samples have been evaluated and compared. In particular, trihalomethane and haloacetic acids formation potentials were measured. Laboratory batch scale experiments were carried out as a function of ozone and UV dosage in order to study the removal kinetics. It is concluded that the combined O3-UV AOP is more effective than either the ozone or UV treatment alone. Ozone-UV AOP is capable of mineralizing up to 50% of the total organic carbon from the raw source water at an ozone dose of 0.62+/-0.019 mg O3/mL and a UV dose of 1.61 W s/cm2. In addition, O3-UV AOP can reduce trihalomethane formation potential by roughly 80% and haloacetic acids formation potential by roughly 70% at the same ozone and UV dosage.

  14. Ozone concentrations in air flowing into New York State

    Aleksic, Nenad; Kent, John; Walcek, Chris


    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.


    Burton, Andrew J. [Michigan Technological University; Zak, Donald R. [University of Michigan; Kubiske, Mark E. [USDA Forest Service; Pregitzer, Kurt S. [University of Idaho


    photosynthesis increased with elevated CO2 and tended to decrease with elevated O3, compared to the control. In contrast to aspen and birch, maple photosynthesis was not enhanced by elevated CO2. Elevated O3 did not cause significant reductions in maximum photosynthesis in birch or maple. In addition, photosynthesis in ozone sensitive clones was affected to a much greater degree than that in ozone tolerant aspen clones. Treatment effects on photosynthesis contributed to CO2 stimulation of aboveground and belowground growth that was species and genotype dependent, with birch and aspen being most responsive and maple being least responsive. The positive effects of elevated CO2 on net primary productivity NPP were sustained through the end of the experiment, but negative effects of elevated O3 on NPP had dissipated during the final three years of treatments. The declining response to O3 over time resulted from the compensatory growth of O3-tolerant genotypes and species as the growth of O3-sensitive individuals declined over time. Cumulative NPP over the entire experiment was 39% greater under elevated CO2 and 10% lower under elevated O3. Enhanced NPP under elevated CO2 was sustained by greater root exploration of soil for growth-limiting N, as well as more rapid rates of litter decomposition and microbial N release during decay. Results from Aspen FACE clearly indicate that plants growing under elevated carbon dioxide, regardless of community type or ozone level, obtained significantly greater amounts of soil N. These results indicate that greater plant growth under elevated carbon dioxide has not led to “progressive N limitation”. If similar forests growing throughout northeastern North America respond in the same manner, then enhanced forest NPP under elevated CO2 may be sustained for a longer duration than previously thought, and the negative effect of elevated O3 may be diminished by compensatory growth of O3-tolerant plants as they begin to dominate forest communities. By

  16. Charge-Transfer Complexes and Photochemistry of Ozone with Ferrocene and n-Butylferrocene: A UV-vis Matrix-Isolation Study.

    Pinelo, Laura F; Kugel, Roger W; Ault, Bruce S


    The reactions of ozone with ferrocene (cp2Fe) and with n-butylferrocene (n-butyl cp2Fe) were studied using matrix isolation, UV-vis spectroscopy, and theoretical calculations. The codeposition of cp2Fe with O3 and of n-butyl cp2Fe with O3 into an argon matrix led to the production of 1:1 charge-transfer complexes with absorptions at 765 and 815 nm, respectively. These absorptions contribute to the green matrix color observed upon initial deposition. The charge-transfer complexes underwent photochemical reactions upon irradiation with red light (λ ≥ 600 nm). Theoretical UV-vis spectra of the charge-transfer complexes and photochemical products were calculated using TD-DFT at the B3LYP/6-311G++(d,2p) level of theory. The calculated UV-vis spectra were in good agreement with the experimental results. MO analysis of these long-wavelength transitions showed them to be n→ π* on the ozone subunit in the complex and indicated that the formation of the charge-transfer complex between ozone and cp2Fe or n-butyl cp2Fe affects how readily the π* orbital on O3 is populated when red light (λ ≥ 600 nm) is absorbed. 1:1 complexes of cp2Fe and n-butyl cp2Fe with O2 were also observed experimentally and calculated theoretically. These results support and enhance previous infrared studies of the mechanism of photooxidation of ferrocene by ozone, a reaction that has considerable significance for the formation of iron oxide thin films for a range of applications.

  17. An assessment of the impact of ambient ozone on field-grown crops in New Jersey using the EDU method: part 2-soybean (Glycine max (L.) Merr.).

    Brennan, E G; Clarke, B B; Greenhalgh-Weidman, B; Smith, G


    The yields of eleven commercially grown soybean cultivars were compared in ethylenediurea (EDU)-treated and non-treated field plots in New Brunswick, New Jersey, over a 4 year period. No statistically significant difference between treatments was found for any cultivar; the inference being ambient ozone did not adversely affect soybean yield. Succeeding field experiments supported this interpretation of the data. 'Sanilac' white bean, a legume known to be more sensitive to O(3) than soybean, was found to produce a significantly greater yield in EDU-treated than non-treated plots, unlike a companion planting of 'Williams 82' soybean which did not exhibit the differential response. The results indicated that the specific EDU protocol used in the soybean experiments is capable of detecting an ozone effect in a legume. Moreover, in a concurrent greenhouse experiment the yield of EDU-treated Sanilac white bean was not significantly different from non-treated plants in the absence of ozone pollution. In a dose-response field experiment during a year of unusually high O(3) pollution, yield of 'Williams 82' increased slightly with each EDU increment up to 500 ppm and decreased at 1000 ppm. The difference between non-treated and EDU-treated plants, however, was not statistically significant. There was no evidence to suggest that the EDU concentration (500 ppm) used in previous soybean experiments reduced seed yield. Fortuitously, the tolerance of commercially-grown soybean to ambient ozone is at least partially conditioned by the practce of not irrigating the crop. The New Jersey results are in agreement with reports from Maryland, Georgia and Tennessee in which an adverse impact of ambient O(3) was not found in soybean, but contrary to a current predictive model.

  18. Ozone exposure affects leaf wettability and tree water balance

    Schreuder, M.D.J.; Hove, van L.W.A.; Brewer, C.A.


    Relatively little is known about the influences of growing-season background ozone (O3) concentrations on leaf cuticles and foliar water loss. Using fumigation chambers, leaf wettability and foliar water loss were studied in two poplar species, Populus nigra and P. euramericana, and a conifer, Pseud

  19. Understanding and improving global crop response to ozone pollution

    Concentrations of ground-level ozone ([O3]) over much of the Earth’s land surface have more than doubled since pre-industrial times. The air pollutant is highly variable over time and space, which makes it difficult to assess the average agronomic and economic impacts of the pollutant as well as to ...

  20. Dielectric Properties of Dy2O3 -Doped ( Ba, Sr) TiO3 Ceramics

    Huang Xinyou; Gao Chunhua; Chen Xiangchong; Zheng Xialian; Huang Guojun; Liu Huiping


    The effects of Dy2O3 doping on the dielectric properties of (Ba, Sr)TiO3 series capacitor ceramics prepared using solid-state reaction method were studied. With the increasing of Dy2O3 additive , the dielectric constant (ε) of materials increases to a maximum when w(Dy2O3 ) is about 0.5% ,while the dielectric loss(tanδ) decreases. The BST ceramics with highε ( = 5245 ), low tanδ ( = 0. 0026 ) and high DC breakdown voltage ( = 5.5 mV ·m-1 ) were obtained. The influencing mechanism of Dy2O3 on the dielectric properties of (Ba, Sr)TiO3 ceramics was studied, thus providing the basis for preparation of capacitor ceramics.

  1. Interfacial Ferromagnetism in LaNiO3/CaMnO3 Superlattices

    Grutter, Alexander J.; Yang, Hao; Kirby, B. J.; Fitzsimmons, M. R.; Aguiar, Jeffery A.; Browning, Nigel D.; Jenkins, C. A.; Arenholz, Elke; Mehta, V. V.; Alaan, U. S.; Suzuki, Y.


    We observe interfacial ferromagnetism in superlattices of the paramagnetic metal LaNiO3 and the antiferromagnetic insulator CaMnO3. LaNiO3 exhibits a thickness dependent metal-insulator transition and we find the emergence of ferromagnetism to be coincident with the conducting state of LaNiO3. That is, only superlattices in which the LaNiO3 layers are metallic exhibit ferromagnetism. Using several magnetic probes, we have determined that the ferromagnetism arises in a single unit cell of CaMnO3 at the interface. Together these results suggest that ferromagnetism can be attributed to a double exchange interaction among Mn ions mediated by the adjacent itinerant metal.

  2. Interfacial ferromagnetism in LaNiO3/CaMnO3 superlattices.

    Grutter, A J; Yang, H; Kirby, B J; Fitzsimmons, M R; Aguiar, J A; Browning, N D; Jenkins, C A; Arenholz, E; Mehta, V V; Alaan, U S; Suzuki, Y


    We observe interfacial ferromagnetism in superlattices of the paramagnetic metal LaNiO3 and the antiferromagnetic insulator CaMnO3. LaNiO3 exhibits a thickness dependent metal-insulator transition and we find the emergence of ferromagnetism to be coincident with the conducting state of LaNiO3. That is, only superlattices in which the LaNiO3 layers are metallic exhibit ferromagnetism. Using several magnetic probes, we have determined that the ferromagnetism arises in a single unit cell of CaMnO3 at the interface. Together these results suggest that ferromagnetism can be attributed to a double exchange interaction among Mn ions mediated by the adjacent itinerant metal.

  3. Chemical stability of La2O3 in La2O3-Mo cathode materials


    Chemical stability of La2O3 in carbonized and uncarbonized La2O3-Mo cathodes was studied by in-situ XPS analysis. Experimental results show that chemical stability of La2O3 is not good enough. In vacuum and at high temperature, oxygen can be dissociated from the lattice of La2O3 in the uncarbonized La2O3-Mo cathode. Binding energy shifts of La?3d5/2 and La?3d3/2 core peaks, and obvious decrease of satellite peak intensity in La?3d doublet with increasing temperature show that metallic La appears at carbonized La2O3-Mo cathode surface at high temperature.

  4. Impacts of summer ozone exposure on the growth and overwintering of UK upland vegetation

    Hayes, Felicity; Mills, Gina; Williams, Philip; Harmens, Harry; Büker, Patrick

    The effects of ozone exposure on species of an upland grassland were assessed. Thirty-three species from Snowdonia, North Wales, UK, were exposed for 10 weeks to a weekly episodic ozone regime in solardomes representing predicted future concentrations. Two solardomes were used as controls, with ozone added to charcoal-filtered air to give a continuous ozone concentration of 30 ppb (O 3(30)). A weekly episodic ozone regime was applied to two other solardomes, with concentrations rising for 8 h per day to 80 ppb on day 1, 100 ppb on days 2 and 3, and 80 ppb on day 4; ozone concentrations remained at 30 ppb at all other times (O 3(30+peaks)). The control and background ozone concentrations of 30 ppb were maintained throughout the night as well as during the daytime. During exposure to the episodic ozone regime, some species were sensitive to ozone and showed ozone-specific leaf injury symptoms (e.g . Carex echinata) and/or premature senescence (e.g. Festuca rubra) and/or changes in above-ground biomass (e.g. Armeria maritima), whereas other species (e.g Holcus lanatus and Carex demissa) showed no effects. Some species, although showing no effects during the 10-week ozone exposure, showed carry-over effects on biomass the following spring, after a winter period of ambient ozone exposure (e.g. Galium saxatile, Nardus stricta and Saxifraga stellaris). The carry-over effects shown in this study indicate the potential ecological impact of ozone on semi-natural vegetation species and indicate the importance of longer-term studies on the effects of ozone on plants.

  5. Interannual variability in ozone removal by a temperate deciduous forest

    Clifton, O. E.; Fiore, A. M.; Munger, J. W.; Malyshev, S.; Horowitz, L. W.; Shevliakova, E.; Paulot, F.; Murray, L. T.; Griffin, K. L.


    The ozone (O3) dry depositional sink and its contribution to observed variability in tropospheric O3 are both poorly understood. Distinguishing O3 uptake through plant stomata versus other pathways is relevant for quantifying the O3 influence on carbon and water cycles. We use a decade of O3, carbon, and energy eddy covariance (EC) fluxes at Harvard Forest to investigate interannual variability (IAV) in O3 deposition velocities (vd,O3). In each month, monthly mean vd,O3 for the highest year is twice that for the lowest. Two independent stomatal conductance estimates, based on either water vapor EC or gross primary productivity, vary little from year to year relative to canopy conductance. We conclude that nonstomatal deposition controls the substantial observed IAV in summertime vd,O3 during the 1990s over this deciduous forest. The absence of obvious relationships between meteorology and vd,O3 implies a need for additional long-term, high-quality measurements and further investigation of nonstomatal mechanisms.

  6. Ozone-Induced Pulmonary Injury and Inflammation are Modulated by Adrenal-Derived Stress Hormones

    Ozone exposure promotes pulmonary injury and inflammation. Previously we have characterized systemic changes that occur immediately after acute ozone exposure and are mediated by neuro-hormonal stress response pathway. Both HPA axis and sympathetic tone alterations induce the rel...

  7. Inflammatory Cytokines and White Blood Cell Counts Response to Environmental Levels of Diesel Exhaust and Ozone Inhalation Exposures

    Epidemiological observations of urban inhalation exposures to diesel exhaust (DE) and ozone (O3) have shown pre-clinical cardiopulmonary responses in humans. Identifying the key biological mechanisms that initiate these health bioindicators is difficult due to variability in envi...

  8. Ozone source attribution during a severe photochemical smog episode in Beijing,China


    Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26―July 2,2000.Ozone Source Apportionment Technology(OSAT) and Geographic Ozone Assessment Technology(GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the relative importance of different ways by which regional sources affected the O3 levels in Beijing urban areas,and to investigate the sensitivity of O3 formation to the precursors during the episode.The O3 pollution in Beijing showed a significant spatial distribution with strong regional contribution.The results suggested that the plume originating from Beijing urban areas greatly affected the O3 concentrations at the Dingling site,accounting for 55% of elevated O3 there,while O3 pollution in the Beijing urban areas resulted from both local emissions and those from Tianjin and the south of Hebei Province.Transport of O3 was responsible for about 70% of the regional O3 contribution to Beijing urban areas,while transport of O3 precursors accounted for the remainder.The formation of O3 was limited by volatile organic compounds(VOCs) in the urban areas of Beijing,while being more sensitive to NOx levels in the suburban and more remote areas.Therefore,it is necessary to consider a large number of factors,including impacts of emissions from different regions,the two modes of regional contribution as well as the sensitivity of O3 formation to precursors,in the design of emissions control strategies for O3 reduction in Beijing.

  9. Ozone source attribution during a severe photochemical smog episode in Beijing,China

    WANG XueSong; LI JinLong; ZHANG YuanHang; XIE ShaoDong; TANG XiaoYan


    Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions (CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26-July 2,2000.Ozone Source Apportionment Technology (OSAT) and Geographic Ozone Assessment Technology (GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the relative importance of different ways by which regional sources affected the O3 levels in Beijing urban areas,and to investigate the sensitivity of O3 formation to the precursors during the episode.The O3 pollution in Beijing showed a significant spatial distribution with strong regional contribution.The results suggested that the plume originating from Beijing urban areas greatly affected the O3 concentrations at the Dingling site,accounting for 55% of elevated O3 there,while O3 pollution in the Beijing urban areas resulted from both local emissions and those from Tianjin and the south of Hebei Province.Transport of O3 was responsible for about 70% of the regional O3 contribution to Beijing urban areas,while transport of O3 precursors accounted for the remainder.The formation of O3 was limited by volatile organic compounds (VOCs) in the urban areas of Beijing,while being more sensitive to NO,levels in the suburban and more remote areas.Therefore,it is necessary to consider a large number of factors,including impacts of emissions from different regions,the two modes of regional contribution as well as the sensitivity of O3 formation to precursors,in the design of emissions control strategies for O3 reduction in Beijing.

  10. Vacancy induced metallicity at the CaHfO3/SrTiO3 interface

    Nazir, Safdar


    Density functional theory is used to study the electronic properties of the oxide heterointerfaceCaHfO3/SrTiO3. Structural relaxation is carried out with and without O vacancies. As compared to related interfaces, strongly reduced octahedral distortions are found. Stoichiometric interfaces between the wide band gap insulatorsCaHfO3 and SrTiO3 turn out to exhibit an insulating state. However, interface metallicity is introduced by O vacancies, in agreement with experiment. The reduced octahedral distortions and necessity of O deficiency indicate a less complicated mechanism for the creation of the interfacial electron gas.

  11. Role of tachykinins in ozone-induced acute lung injury in guinea pigs

    Tepper, J.S.; Costa, D.L.; Fitzgerald, S.; Doerfler, D.L.; Bromberg, P.A. (ManTech Environmental Technology, Inc., Research Triangle Park, NC (United States))


    To examine the hypothesis that the acute reversible changes caused by ozone (O3) exposure are mediated by tachykinin release, guinea pigs were depleted of tachykinins by use of repeated capsaicin (CAP) injections before O3 exposure in an attempt to prevent O3-induced functional changes. Unexpectedly, CAP pretreatment caused divergent results in the functional responses to O3. Ventilatory measurements obtained from CAP-pretreated O3-exposed (CAP-O3) animals were exacerbated rather than diminished compared with the effects of O3 alone. Similarly, lavage fluid protein accumulation was enhanced in the CAP-O3 group compared with the O3-exposed group. In better agreement with our initial hypothesis, the CAP-O3 group was less responsive than the O3-exposed animals to histamine aerosol challenge. Additionally, Evans blue dye accumulation, a hallmark of tachykinin release, was increased in O3-exposed animals and was partially blocked in the CAP-O3 group. These data suggest that tachykinin-containing sensory fibers are unlikely to mediate the acute effects of O3 exposure on tidal breathing and lavage fluid protein accumulation but may play a role in causing post-O3 airway hyperreactivity and protein extravasation into the trachea.

  12. Basic Ozone Layer Science

    Learn about the ozone layer and how human activities deplete it. This page provides information on the chemical processes that lead to ozone layer depletion, and scientists' efforts to understand them.

  13. Ozone Layer Protection

    ... Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to ... Managing Refrigerant Emissions Stationary Refrigeration and Air Conditioning Car and Other Mobile Air Conditioning GreenChill Partnership Responsible ...

  14. Stratospheric contribution to surface ozone in the desert Southwest during the 2013 Las Vegas Ozone Study

    Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II; Brioude, J. F.; Cooper, O. R.; Holloway, J. S.; Lin, M.; Marchbanks, R.; Pierce, R. B.; Reddy, P. J.; Sandberg, S.; Weickmann, A. M.; Williams, E. J.; Gustin, M. S.; Iraci, L. T.; Leblanc, T.; Yates, E. L.


    The 2013 Las Vegas Ozone Study (LVOS) was designed to investigate the potential impact of stratosphere-troposphere transport (STT) and long-range transport of pollution from Asia on surface O3 concentrations in Clark County, NV. This measurement campaign, which took place in May and June of 2013, was conducted at Angel Peak, NV, a high elevation site about 2.8 km above mean sea level and 45 km west of Las Vegas. The study was organized around the NOAA ESRL truck-based TOPAZ scanning ozone lidar with collocated in situ sampling of O3, CO, and meteorological parameters. These measurements were supported by the NOAA/NESDIS real time modelling system (RAQMS), FLEXPART particle dispersion model, and the NOAA GFDL AM3 model. In this talk, I will describe one of several STT events that occurred during the LVOS campaign. This intrusion, which was profiled by TOPAZ on the night of May 24-25, was also sampled by the NASA Alpha Jet, the Table Mountain ozone lidar, and by an ozonesonde flying above southern California. This event also led to significant ozone increases at surface monitors operated by Clark County, the California Air Resources Board, the U.S. National Park Service, and the Nevada Rural Ozone Initiative (NRVOI), and resulted in exceedances of the 2008 75 ppbv O3 NAAQS both in Clark County and in surrounding areas of Nevada and southern California. The potential implications of this and similar events for air quality compliance in the western U.S. will be discussed.

  15. Characterising tropospheric O3 and CO around Frankfurt over the period 1994-2012 based on MOZAIC-IAGOS aircraft measurements

    Petetin, Hervé; Thouret, Valérie; Fontaine, Alain; Sauvage, Bastien; Athier, Giles; Blot, Romain; Boulanger, Damien; Cousin, Jean-Marc; Nédélec, Philippe


    In the framework of the MOZAIC-IAGOS programme, vertical profiles of ozone (O3) and carbon monoxide (CO) have been available since 1994 and 2002, respectively. This study investigates the variability and trend of both species in three tropospheric layers above the German airports Frankfurt and Munich. About 21 300 flights have taken place over the period 1994-2012, which represents the worldwide densest vertical in situ data set of O3 and CO (with ˜ 96 flights per month on average). The mean vertical profile of ozone shows a strong gradient in the first kilometre during the whole year and in the tropopause region in spring and summer. The mean vertical profile of CO is characterised by high mixing ratios at the ground, a strong decrease in the first kilometre, in particular in winter and autumn, and a moderate one in the free troposphere. O3 minimises in November-December and shows a broad spring/summer maximum in the lower and mid-troposphere and a sharp maximum in summer in the upper troposphere. The seasonal variation of CO shows a broad minimum in July-October close to the surface and in September-October it occurs higher in the troposphere, while the maximum occurs in February-April in the whole troposphere. Over the period 1994-2012, O3 has changed insignificantly (at a 95 % confidence level), except in winter where a slightly significant increase (from +0.83 [+0.13;+1.67] % yr-1 in the LT to +0.62 [+0.02;+1.22] % yr-1 in the UT, relative to the reference year 2000) is found. The O3 5th percentile shows similar upward trends at the annual scale in all three tropospheric layers. All trends remain insignificant for the O3 95th percentile. In contrast, for CO the mean as well as its 5th and 95th percentiles decrease both at the annual scale and at the seasonal scale in winter, spring and summer (although not always in all three tropospheric layers) with trends ranging between -1.22 [-2.27;-0.47] and -2.63 [-4.54;-1.42] % yr-1, relative to the reference year

  16. Effects of pre-ozonation on organic matter removal by coagulation with IPF-PACI

    LIU Hai-long; WANG Dong-sheng; SHI Bao-you; WANG Min; TANG Hong-xiao


    Ozone plays an important role as a disinfectant and oxidant in potable water treatment practice and is increasingly being used as a pre-oxidant before coagulation. The purpose of this study is to obtain insight into the mechanisms that are operative in pre-ozonized coagulation. Effects ofpre-ozonation on organic matter removal during coagulation with IPF-PACl were investigated by using PDA (photometric disperse analysis), apparent molecular weight distribution and chemical fractionation. The dynamic formation of flocs during coagulation process was detected. Changes of aquatic organic matter (AOM) structure resulted from the influence of pre-ozonation were evaluated. Results show that dosage of O3 and characteristics of AOM are two of the major factors influencing the performance of O3 on coagulation. No significant coagulation-aid effect of O3 was observed for all experiments using either AlCl3 or PACl. On the contrary, with the application of pre-ozonation, the coagulation efficiency of AlCl3 was significantly deteriorated,reflected by the retardation of floc formation, and the removal decreases of turbidity, DOC, and UV254. However, if PACl was used instead of AlCl3, the adverse effects of pre-ozonation were mitigated obviously, particularly when the O3 dosage was less than 0.69(mg O3/mg TOC). The difference between removals of UV254 and DOC indicated that pre-ozonation greatly changed the molecular structure of AOM, but its capability of mineralization was not remarkable. Only 5% or so DOC was removed by pre-ozonation at0.6-0.8 mg/L alone. Fractionation results showed that the organic products of pre-ozonation exhibited lower molecular weight and more hydrophilicity, which impaired the removal of DOC in the following coagulation process.

  17. Is the HO4- anion a key species in the aqueous-phase decomposition of ozone?

    Anglada, Josep M; Torrent-Sucarrat, Miquel; Ruiz-Lopez, Manuel F; Martins-Costa, Marilia


    The role of the HO(4)(-) anion in atmospheric chemistry and biology is a matter of debate, because it can be formed from, or be in equilibrium with, key species such as O(3) + HO(-) or HO(2) + O(2) (-). The determination of the stability of HO(4)(-) in water therefore has the greatest relevance for better understanding the mechanism associated with oxidative cascades in aqueous solution. However, experiments are difficult to perform because of the short-lived character of this species, and in this work we have employed DFT, CCSD(T) complete basis set (CBS), MRCI/aug-cc-pVTZ, and combined quantum mechanics/molecular mechanics (QM/MM) calculations to investigate this topic. We show that the HO(4)(-) anion has a planar structure in the gas phase, with a very large HOO-OO bond length (1.823 Å). In contrast, HO(4)(-) adopts a nonplanar configuration in aqueous solution, with huge geometrical changes (up to 0.232 Å for the HOO-OO bond length) with a very small energy cost. The formation of the HO(4)(-) anion is predicted to be endergonic by 5.53±1.44 and 2.14±0.37 kcal mol(-1) with respect to the O(3) + HO(-) and HO(2) + O(2)(-) channels, respectively. Moreover, the combination of theoretical calculations with experimental free energies of solvation has allowed us to obtain accurate free energies for the main reactions involved in the aqueous decomposition of ozone. Thus, the oxygen transfer reaction (O(3) + OH(-) → HO(2) + O(2)(-)) is endergonic by 3.39±1.80 kcal mol(-1), the electron transfer process (O(3) + O(2)(-) → O(3)(-) + O(2)) is exergonic by 31.53±1.05 kcal mol(-1), supporting the chain-carrier role of the superoxide ion, and the reaction O(3) + HO(2)(-) → OH + O(2)(-) + O(2) is exergonic by 12.78±1.15 kcal mol(-1), which is consistent with the fact that the addition of small amounts of HO(2)(-) (through H(2)O(2)) accelerates ozone decomposition in water. The combination of our results with previously reported thermokinetic data provides some

  18. Soil drench of ethylenediurea (EDU protects sensitive trees from ozone injury

    Paoletti E


    Full Text Available Ozone (O3 is the air pollutant of major concern for vegetation. Levels in Mediterranean cities may exceed the criteria for vegetation protection. Ozone may induce a number of plant responses, e.g., visible injury on the leaves, that affect the ornamental value of urban forests. Antioxidant application may protect sensitive plants from ozone. The most successful synthetic antioxidant is ethylenediurea (EDU. Here we set the optimal EDU dose and concentration (260 mg m-2 leaf, 450 ppm for protecting adult Fraxinus excelsior trees from ozone visible injury by means of EDU applications as soil drench.

  19. Ozone Layer Observations

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


    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.

  20. Ozonation of metoprolol in aqueous solution: ozonation by-products and mechanisms of degradation.

    Tay, Kheng Soo; Rahman, Noorsaadah Abd; Abas, Mhd Radzi Bin


    This study investigated the degradation pathway of metoprolol, a widely used β-blocker, in the ozonation via the identification of generated ozonation by-products (OPs). Structure elucidation of OPs was performed using HPLC coupled with quadrupole time-of-flight high-resolution mass spectrometry. Seven OPs were identified, and four of these have not been reported elsewhere. Identified OPs of metoprolol included aromatic ring breakdown by-products; aliphatic chain degraded by-products and aromatic ring mono-, di-, and tetrahydroxylated derivatives. Based on the detected OPs, metoprolol could be degraded through aromatic ring opening reaction via reaction with ozone (O3) and degradation of aliphatic chain and aromatic ring via reaction with hydroxyl radical (•OH).

  1. Wettability of silicon carbide ceramic by Al2O3/Dy2O3 and Al2O3/Yb2O3 systems

    J.A.da Silva; B.M.Moreschi; G.C.R.Garcia; S.Ribeiro


    Wettability is an important phenomenon in the liquid phase sintering of silicon carbide (SiC) ceramics.This work involved a study of the wetting of SiC ceramics by two oxide systems,Al2O3/Dy2O3 and Al2O3/Yb2O3,which have so far not been studied for application in the sintering of SiC ceramics.Five mixtures of each system were prepared,with different compositions close to their respective eutectic ones.Samples of the mixtures were pressed into cylindrical specimens,which were placed on a SiC plate and subjected to temperatures above their melting points using a graphite resistance furnace.The behavior of the melted mixtures on the SiC plate was observed by means of an imaging system using a CCD camera and the sessile drop method was employed to determine the contact angle,the parameter that measures the degree of wettability.The results of variation in the contact angle as a function of temperature were plotted in graphic form which showed that the curves displayed a fast decline and good spreading.All the samples of the two systems presented final contact angles of 40° to 10° indicating their good wetting on SiC in the argon atmosphere.The melted/solidified area and interface between SiC and melted/solidified phase were evaluated by scanning electron microscopy (SEM) and their crystalline phases were identified by X-ray diffraction (DRX).The DRX analysis showed that Al2O3 and RE2O3 reacted and formed the Dy3Al5O12 (DyAg) and Yb3Al5O12 (YbAg) phases.The results indicated that the two systems had a promising potential as additives for the sintering of SiC ceramics.

  2. Structural properties of Y2O3–Al2O3 liquids and glasses: An overview

    Wilding, Martin C.; Wilson, Mark; McMillan, Paul F.; Benmore, Chris J.; Weber, J. K.R.; Deschamps, Thierry; Champagnon, Bernard


    Liquids in the system Y2O3- Al2O3 have been the subject of considerable study because of the reported occurrence of a first-order density and entropy-driven liquid-liquid phase transition (LLPT) in the supercooled liquid state. The observations have become controversial because of the presence of crystalline material that can be formed simultaneously and that can mask the nucleation and growth of the lower density liquid. The previous work is summarized here along with arguments for and against the different viewpoints. Also two studies have been undertaken to investigate the LLPT in this refractory system with emphasis on determining the structure of unequivocally amorphous materials. These include the in situ high energy X-ray diffraction (HEXRD) of supercooled Y2O3 - Al2O3 liquids and the low frequency vibrational dynamics of recovered glasses. Manybody molecular dynamics simulations are also used to interpret the results of both studies. The HEXRD measurements, combined with aerodynamic levitation and rapid data acquisition techniques, show that for the 20 mol% Y2O3 (i.e. AlY20) liquid there is a shift in the position of the first peak in the diffraction pattern over a narrow temperature range (2100-1800 K) prior to crystallization. Microbeam Raman spectroscopy measurements made on AlY20 glasses clearly show contrasting spectra in the low frequency part of the spectrum for low(LDA) and high-density (HDA) glassy regions. The molecular dynamics simulations identify contrasting coordination environments around oxygen anions for the high- (HDL) and low-density (LDL) liquids. (C) 2014 Elsevier B.V. All rights reserved.

  3. Comments on "Global crop yield reductions due to surface ozone exposure: 1. Year 2000 crop production losses and economic damage" and "Global crop yield reductions due to surface ozone exposure: 2. Year 2030 potential crop production losses and economic damage under two scenarios of O3 pollution" by Shiri Avnery, Denise L. Mauzerall, Junfeng Liu, Lary W. Horowitz [Atmospheric Environment 45, 2284-2296 and 2297-2309.

    Nawahda, Amin


    The Authors (Avnery et al., 2011a,b) estimated the relative yield losses of wheat crop in China in 2000 and 2030 to be 15%-20% and 25%-30%, respectively. And the relative yield losses of soybean crop in China in 2000 and 2030 to be 20%-25% and 30%-45%, respectively. These findings do not agree with the information that shows the relative yield losses of wheat crop should be greater than those of soybean crop in China. Additionally, do not agree with the findings of previous studies.

  4. Research on the degradation 1,2,4-trichlorobenzene by O3/H2O2/UV process%O3/H2O2/UV降解1,2,4-三氯苯的研究

    孙云娜; 魏东洋; 陆桂英; 贾晓珊; 李杰; 许振成


    采用O3/H2O2/UV工艺处理1,2,4-三氯苯(TCB)模拟废水,考察了TCB初始浓度、pH、H2O2投加量及O3转化率等因素对O3/H2O2/UV降解TCB的影响,推断了TCB可能的降解途径.结果表明:(1)H2O2、O3、UV、O3/H2O2、O3/H2 O2/UV 5种体系对TCB的降解效果为H2O2 <UV<O3O3/H2O2 <O3/H2O2/UV.(2)O3/H2O2/UV对TCB降解的单因素实验表明,TCB初始浓度越小、O3转化率越高,TCB去除率越大;H2O2的投加量存在一个最佳值,低于或高于这个最佳值都会导致TCB去除率的下降;在碱性条件下,TCB的降解效果更佳.(3)推测O3/H2O2/UV工艺降解TCB的机制主要为TCB与·OH的反应过程,其历程可分为3步:反应初期阶段,苯环上的C-Cl被·OH攻击,产生羟基化氯苯化合物;苯环得到活化,·OH进攻苯环,产生低氯代苯类物质;羟基化合物破环,生成小分子有机酸.%The O3/H2O2/UV combination process was employed to treat the simulated 1,2,4-trichlorobenzene (TCB) containing wastewater. The effect of initial TCB concentration, pH, H2O2 dosage and ozone transform rate on TCB removal efficiency was investigated. The potential degradation pathway of TCB was proposed with the help of GC,GC/MS and HPLC analysis. Results showed that the removal efficiency of TCB in 5 degradation system (H2O2 , O3,UV,O3/H2O2,O3/H2O2/UV) followed the order of H2O2 <UV<03 <O3/H2O2 <O3/H2 O2/UV. The single-factor test of O3/H2O2/UV degradation system showed that higher TCB removal efficiency always found in system with lower initial TCB efficiency or higher ozone transform rate. H2O2 dosage had an optimum value, below or above the optimum value could reduce the TCB removal efficiency. Alkaline condition of O3/H2O2/UV process was in favor to the TCB degradation. The mechanism of TCB degradation in O3/H2O2/UV system was the reaction between TCB and o OH. In the early stages of degradation, the C-Cl bond in benzene rings was attacked by o OH and produced hy-droxylation chlorobenzene

  5. O(^3 p) Doped Helium Droplets

    Brice, Joseph T.; Douberly, Gary E.


    Atomic oxygen (^3 P) is generated via thermolysis in a commerical thermal gas cracker (Mantis Ltd. MGC-75). Complexes with HCN were investigated to qualitatively assess the doping efficiency of O(^3 P) into a helium droplet. Theoretical calculations of a linear O \\cdot\\cdot\\cdot HCN (^3 Σ) complex at the CCSD(T)/aug-cc-pVTZ level are consistent with the rotational constants extracted from the rotational substructure in the experimental spectra, and with dipole moments approximated from Stark spectra. The thermal source will be used to study reactions between O(^3 P) and hydrocarbons in helium droplets, and preliminary data on this topic will be presented.

  6. Temporal and spatial characteristics of surface ozone depletion events from measurements over the Arctic Ocean

    Halfacre, J. W.; Knepp, T. N.; Stephens, C. R.; Pratt, K. A.; Shepson, P.; Simpson, W. R.; Peterson, P. K.; Walsh, S. J.; Matrai, P. A.; Bottenheim, J. W.; Netcheva, S.; Perovich, D. K.; Richter, A.


    Arctic tropospheric ozone depletion events (ODEs) have been studied primarily from coastal sites since the mid 1980s with only a few studies occurring over the Arctic Ocean, the hypothesized site of initiation. Despite a multitude of studies, some basic characteristics of ODEs remain poorly defined, including their temporal, spatial, and meteorological characteristics. Several deployments of autonomous, ice-tethered buoys (O-Buoys) were used to elucidate such characteristics from both the Arctic Ocean and coastal sites. The apparent first order decays imply an ozone lifetime (median of 11 hours) that would correspond to a very large BrO concentration, relative to BrO observations obtained from the buoys. These results suggest that ODEs involve a large, unaccounted for source of bromine atoms, that there is a significant contribution from other mechanisms possibly not involving bromine, or that the majority of observed ODEs represent advection of previously-depleted air to the buoy site, even in the Arctic Ocean. Using backward air mass trajectories, the spatial scales for ODEs (defined by time periods with O3 ≤ 15 nmol/mol) were estimated to be ~1800 km (mode), suggesting that most of the lower troposphere above the Arctic Ocean is frequently, at least partially, depleted of ozone. Using the same method, areas estimated to be highly depleted of O3 (ice-tethered O-Buoys provide unique data to study the characteristics of ODEs; however, more remote and simultaneous surface observations over the Arctic Ocean are necessary to enable study of both the site(s) and mechanism(s) of ODE initiation.

  7. Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

    O. J. Squire


    Full Text Available Isoprene is a precursor to tropospheric ozone, a key pollutant and greenhouse gas. Anthropogenic activity over the coming century is likely to cause large changes in atmospheric CO2 levels, climate and land use, all of which will alter the global vegetation distribution leading to changes in isoprene emissions. Previous studies have used global chemistry–climate models to assess how possible changes in climate and land use could affect isoprene emissions and hence tropospheric ozone. The chemistry of isoprene oxidation, which can alter the concentration of ozone, is highly complex, therefore it must be parameterised in these models. In this work we compare the effect of four different reduced isoprene chemical mechanisms, all currently used in Earth-system models, on tropospheric ozone. Using a box model we compare ozone in these reduced schemes to that in a more explicit scheme (the MCM over a range of NOx and isoprene emissions, through the use of O3 isopleths. We find that there is some variability, especially at high isoprene emissions, caused by differences in isoprene-derived NOx reservoir species. A global model is then used to examine how the different reduced schemes respond to potential future changes in climate, isoprene emissions, anthropogenic emissions and land use change. We find that, particularly in isoprene rich regions, the response of the schemes varies considerably. The wide ranging response is due to differences in the types of peroxy radicals produced by isoprene oxidation, and their relative rates of reaction towards NO, leading to ozone formation, or HO2, leading to termination. Also important is the yield of isoprene-nitrates and peroxyacyl nitrate precursors from isoprene oxidation. Those schemes that produce less of these NOx reservoir species, tend to produce more ozone locally and less away from the source region. Additionally, by combining the emissions and O3 data from all of the global model integrations, we

  8. Uptake of ozone to mixed sodium bromide/ citric acid solutions

    Lee, Ming-Tao; Steimle, Emilie; Bartels-Rausch, Thorsten; Kato, Shunsuke; Lampimäki, Markus; Brown, Matthew; van Bokhoven, Jeroen; Nolting, Frithjof; Kleibert, Armin; Türler, Andreas; Ammann, Markus


    Sea-salt solution - air interfaces play an important role in the chemistry of the marine boundary layer. The reaction of ozone (O3) with bromide is of interest in the context of formation of photolabile halogens (Br2, BrCl) in the marine boundary layer. Recent experiments have suggested that the bromide oxidation rate is related to the surface concentration of bromide [1] and inversely related to the gas phase concentration of O3, an indication for a precursor mediated reaction at the surface [2]. So far, the effect of organics (such as those occurring at the ocean surface or in marine aerosols) on the reaction of O3 with bromide aerosols has not been studied yet. In our study we investigate the uptake kinetics of O3 to a mixed solution of sodium bromide (NaBr) and citric acid (CA), which represents highly oxidized organic compounds present in the environment, with a well-established coated wall flow tube technique, which leads to exposure of the film to O3 allowing the heterogeneous reactions to take place and the loss of O3 being measured. The results indicate that the uptake of O3 to the films with the higher bromide concentrations (0.34M and 4M) is independent of the gas phase concentration and roughly consistent with uptake limited by reaction in the bulk. For the lower bromide concentration (84mM), however, we observe a trend of the uptake coefficient to decrease with increasing O3 concentration, indicating an increasing importance of a surface reaction. In an attempt to constrain the kinetic data, we employed X-ray photoelectron spectroscopy (XPS) to get insight into the surface composition of the aqueous solution - air interface. Previous XPS studies have shown that halide ion concentrations are enhanced at the aqueous solution air interface [3-4], which likely promotes the surface reactions of bromide or iodide with O3. A first XPS study of ternary solutions of KI with butanol indicated the importance of specific interactions of the cation with the alcohol

  9. Ozone phytotoxicity in the Western Carpathian Mountains in Slovakia

    Bičárová Svetlana


    Full Text Available In this work, the response of temperate coniferous forests to ozone air pollution (O3 in the mountain environment of the High Tatra Mts. (Western Carpathians was analyzed. The modelling of stomatal O3 flux is a complex method for the estimation of phytotoxicity of O3 pollution to forest vegetation. Stomatal flux-based critical levels (CLef for effects of O3 on radial growth take into account the varying influences of O3 concentration, meteorological variables, soil properties, and phenology. The application of the model DO3SE (Deposition of Ozone for Stomatal Exchange at five experimental plots with altitudes varying from 810 to 1,778 m a.s.l. along vertical and spatial profile in the High Tatra Mts. revealed the high phytotoxic potential of O3 on spruce forests during the growing season 2014. The accumulated stomatal O3 flux above a threshold of Y (1 nmol m−2 s−1, i.e. POD1 (Phytotoxic Ozone Dose ranged from 13.6 mmol m−2 at the Kolové pleso site (1,570 m a.s.l. to 16.2 mmol m−2 at Skalnaté Pleso site (1,778 m a.s.l.. CLef for POD1 (8 mmol m−2 recommended for the protection of spruce forests were exceeded at all experimental plots from early July. Similarly, AOT40 index suggests vulnerability of mountain forests to O3 pollution. AOT40 values increased with altitude and reached values varying from 6.2 ppm h in Stará Lesná (810 m a.s.l. to 10.7 ppm h at Skalnaté Pleso close to the timber line (1,778 m a.s.l.. Concentration-based critical level (CLec of 5,000 ppb h was exceeded from June to August and was different for each experimental site.

  10. Heterogeneous reaction kinetics and mechanism of the nitration of aerosolized protein by O3 and NO2

    Shiraiwa, Manabu; Sosedova, Yulia; Rouvière, Aurélie; Ammann, Markus; Pöschl, Ulrich


    The effects of air pollution on allergic diseases are not yet well-understood. Proteins contained in biogenic aerosol particles (pollen, spores, bacteria, etc.), which accounts for up to 5% of urban air particulate matter, are efficiently nitrated in polluted environments before inhalation and deposition in the human respiratory tract [1], which is likely to trigger immune reactions for allergies. Proteins undergo a nitration reaction that leads to the formation of 3-nitrotyrosine residues. The kinetics and reaction mechanism of protein nitration are still largely unknown. The kinetics of nitration of protein particles by O3 and NO2 was measured using the short-lived radioactive tracer 13N. The routine for the online production of 13N-labeled nitrogen dioxide and the main experimental setup were reported previously [2]. Bovine serum albumin (BSA) was used as a model protein compound. Deliquesced NaCl particles were also used as a reference. Particles generated by an ultrasonic nebulizer were mixed with O3 (0 - 150 ppb) and NO2 (5 - 100 ppb) in a flow tube reactor under humid conditions (30 - 75 % RH), which lead to gel-like swelling of the protein [3, 4]. The reaction time was varied in the range of 4 -10 min by changing the position of the inlet of the reactor. The surface concentration of particles was monitored by a scanning mobility particle sizer (SMPS). After passing through the flow tube reactor, the gas and aerosol flow entered a narrow parallel-plate diffusion denuder coated to selectively absorb gas phase NO2, followed by a particle filter collecting the particles. The γ detectors were attached to each denuders and the filter to count the amount of gamma quanta, which are emitted in the decay of 13N. From the count-rate, the concentration of the corresponding species was derived, which was used for the calculation of uptake coefficients of NO2 (γNO2). In absence of O3 in the flow tube reactor, NO2 uptake by both BSA and deliquesced NaCl were below the

  11. Comparison of temporal and Spatial Characteristics of Ozone Pollution at Ground Level in the Eastern China

    Liu Houfeng


    Monitoring data from ozone(O3) automatic stations in three typical cities with different climatic areas in the southern and northern parts of eastern China are used to analyze temporal and spatial characteristics of ozone pollution at ground level. The results show that ozone pollution level has distinct regional differences and the concentration in the suburbs is higher than that in the urban areas. The seasonal variation of ozone concentration in different climatic areas is greatly affected by the variation of precipitation. Ozone concentration in Shenyang and Beijing , in the temperate zone, has one perennial peak concentration, occurring in early summer,May or June. Ozone concentration in Guangzhou, in sub-tropical zone, has two peak values year round. The highest values occur in October and the secondary high value in June. The ozone season in the south is longer than that in the north. The annual average daily peak value of ozone concentrations in different climates usually occur around 3 pm. The diurnal variation range of ozone concentration declines with the increase of latitude. Ozone concentration does not elevate with the increase of traffic flow. Ozone concentration in Guangzhou has a distinct reverse relation to CO and NOx. This complicated non-linearity indicates that the equilibrium of ozone photochemical reaction has regional differences.Exceeding the rate of Beijing's 1h ozone concentration is higher than that of Guangzhou, whereas the average 8h ozone level is lower than that of Guangzhou, indicating that areas in low latitude are more easily affected by moderate ozone concentrations and longer exposure. Thus,China should work out standards for 8h ozone concentration.

  12. Tailoring the structure and piezoelectric properties of BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 ceramics for high temperature applications

    Bennett, J.; Bell, A. J.; Stevenson, T. J.; Comyn, T. P.


    There is a growing requirement for piezoelectric materials and systems which can operate in extreme environments, for example, oil & gas, and aerospace. Here, we present the high temperature BiFeO3-K0.5Bi0.5TiO3-PbTiO3 (BF-KBT-PT) polycrystalline perovskite system. X-ray diffraction, impedance analysis, and Berlincourt measurements reveal a large region of phase coexistence, which can be tailored to optimise performance; Tc and the tetragonal spontaneous strain correlate strongly with the PbTiO3 concentration. The highest temperature composition has a d33 of 140 pmV-1 with a Tc = 542 °C, occupying previously unchartered territory on the classical d33-TC plot.

  13. Ozone depletion in the interstitial air of the seasonal snowpack in northern Japan

    Momoko Nakayama


    Full Text Available To examine the behaviour of ozone (O3 in the seasonal snowpack, measurements were taken of O3 and CO2 in the interstitial air on Rishiri Island, which is located in northern Japan, during the 2010/11 winter season. Exhibiting variation on timescales ranging from several minutes to several days, the atmospheric O3 in the surface air generally increased from December (38 ppb to April (52 ppb. The ozone mixing ratio sharply decreased below the snow surface. Whereas the CO2 data in the interstitial air indicated that a rapid exchange between the snow and the atmosphere occurred intermittently, the O3 mixing ratio remained low and constant (<5 ppb in the snowpack interior. The vertical profile of the O3 mixing ratio indicates that the e-folding lifetime of the O3 loss reaction was 5.0±2.3 minutes during the day and 10.0±6.3 minutes at night, suggesting photochemical O3 depletion occurred during the daytime. Kinetic experiments using ambient (maritime air and snow indicate that the photochemical O3 loss is proportional to the solar radiation and that the O3 loss rate decreases as dawn approaches during the night. The result of the kinetic experiments using artificial O3 in the pure air and snow suggests the important role of gaseous species in the ambient air towards O3 depletion.

  14. Posttranslational modification of bioaerosol protein by common gas pollutants: NO2 and O3

    Abdullahi Mahmood, Marliyyah; Bloss, William; Pope, Francis


    Air pollution can exacerbate several medical conditions, for example, hay fever and asthma. The global incidence of hay fever has been rising for decades; however, the underlying reasons behind this rise remain unclear. It is hypothesized that the exposure of pollen to common gas phase pollutants, such as nitrogen dioxide (NO2) and ozone (O3), increases the allergenicity of the pollen and thus increases hay fever incidence (Reinmuth-Selzle et al., 2014, Franze, et al., 2005). Since atmospheric pollutants often have greater concentrations within urban areas (in particular NO2) the hypothesis suggests that greater allergenicity should occur in urban areas. Certainly, several studies do suggest higher hay fever incidence within urban areas compared to rural areas (Schröder et al., 2015). Previous published work suggests a link between increased allergies and changes in the chemical composition of pollen protein via posttranslational modification of the protein (Reinmuth-Selzle et al., 2014). This study investigates the posttranslational modification of two highly allergenic pollen species (Birch and Ragweed) that are common in Europe. Within the laboratory, we expose pollen grains to atmospherically relevant exposures of gas phase NO2, O3 and other common gas phase oxidants under a range of environmentally relevant conditions. The effects of the exposures on the biochemistry of the pollen grains were probed using a proteomic approach (liquid chromatography coupled ultra-high resolution spectrometer). Our findings indicate the interaction between gas phase pollutants and pollen cause protein specific modifications; in particular nitration that occurs upon tyrosine residues and nitrosylation on cysteine residues. These modifications may affect human immune response to the pollen protein, which may suggest a possible reason for increased allergies in reaction to such chemically altered protein. Quantification of the relative degree of PTMs, from a variety of

  15. Resistance switching at the interface of LaAlO3/SrTiO3

    Chen, Yunzhong; Zhao, J.L.; Sun, J.R.


    At the interface of LaAlO3/SrTiO3 with film thickness of 3 unit cells or greater, a reproducible electric-field-induced bipolar resistance switching of the interfacial conduction is observed on nanometer scale by a biased conducting atomic force microscopy under vacuum environment. The switching...

  16. Growing LaAlO3/SrTiO3 interfaces by sputter deposition

    Dildar, I.M.; Neklyudova, M.; Xu, Q.; Zandbergen, H.W.; Harkema, S.; Boltje, D.; Aarts, J.


    Sputter deposition of oxide materials in a high-pressure oxygen atmosphere is a well-known technique to produce thin films of perovskite oxides in particular. Also interfaces can be fabricated, which we demonstrated recently by growing LaAlO3 on SrTiO3 substrates and showing that the interface showe

  17. Upper limit to magnetism in LaAlO3/SrTiO3 heterostructures

    Fitzsimmons, M.R.; Hengartner, N.W.; Singh, S.; Zhernenkov, M.; Bruno, F.Y.; Santamaria, J.; Brinkman, Alexander; Huijben, Mark; Molegraaf, Hajo; de la Venta, J.; Schuller, Ivan K.


    Using polarized neutron reflectometry we measured the neutron spin-dependent reflectivity from four LaAlO3/SrTiO3 superlattices. Our results imply that the upper limit for the magnetization averaged over the lateral dimensions of the sample induced by an 11 T magnetic field at 1.7 K is less than 2 G

  18. Ozone production and hydrocarbon reactivity in Hong Kong, Southern China

    J. Zhang


    Full Text Available Data obtained in Hong Kong during the Hong Kong and the Pearl River Delta (PRD Pilot Air Monitoring Study in autumn 2002 are analyzed to unravel the relationship between ground-level ozone (O3, pollution precursors, and cross-border transport. Ten ozone episodes, during which the hourly O3 concentration exceeded 100 ppbv in 9 cases and 90 ppbv in one case, are subject to detailed analysis, including one case with hourly O3 of 203 ppbv, which is the highest concentration on record to date in Hong Kong. Combined with high-resolution back trajectories, dCO/dNOy (the ratio of enhancement of CO concentration above background to that of NOy is used to define whether O3 is locally or regionally produced. Five out of the ten Hong Kong O3-episodes studied show a "pollution signature" that is indicative of impact from Guangdong Province. Examination of speciated volatile organic compounds (VOCs shows that the reactivity of VOCs is dominated by anthropogenic VOCs, of which the reactive aromatics dominate, in particular xylenes and toluene. Calculations using a photochemical box model indicate that between 50–100% of the O3 increase observed in Hong Kong during the O3 episodes can be explained by photochemical generation within the Hong Kong area, provided that nitrous acid (HONO is present at the concentrations derived from this study. An Observation-Based Model (OBM is used to calculate the sensitivity of the O3 production to changes in the concentrations of the precursor compounds. Generally the production of O3 throughout much of the Hong Kong area is limited by VOCs, while high nitric oxide (NO concentrations suppress O3 concentration.

  19. Oxidation Resistance of Fe-13Cr Alloy with Micro-Laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) Films

    Yao Mingming; He Yedong; Wang Deren; Gao Wei


    The micro-laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) composite films were prepared on the surface of Fe-13Cr alloy by an electrochemical process and a sintering process alternately. High-resolution field emission scanning electron microscopy (FE-SEM) was used to characterize the laminated films, indicating that the micro-laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) films have nano-structures. SEM, EDS and mass gain measurement were adopted to study the oxidation resistance of films on Fe-13Cr alloy. It is proved that such micro-laminated films are more effective than ZrO2-Y2O3 or Al2O3-Y2O3 films to resist the oxidation of the alloy, and the oxidation resistance is increased with increasing layers in micro-laminated films. These beneficial effects can be contributed to the mechanism, by which such micro-laminated (ZrO2-Y2O3)/(Al2O3-Y2O3) composite film combines all the beneficial effects and overcomes all the disadvantages of both ZrO2-Y2O3 film and Al2O3-Y2O3 film during oxidation of alloy.

  20. Optimization of O3 as Pre-Treatment and Chemical Enhanced Backwashing in UF and MF Ceramic Membranes for the Treatment of Secondary Wastewater Effluent and Red Sea Water

    Herrera, Catalina


    Ceramic membranes have proven to have many advantages over polymeric membranes. Some of these advantages are: resistance against extreme pH, higher permeate flux, less frequent chemical cleaning, excellent backwash efficiency and longer lifetime. Other main advantage is the use of strong chemical agent such as Ozone (O3), to perform membrane cleaning. Ozone has proven to be a good disinfection agent, deactivating bacteria and viruses. Ozone has high oxidation potential and high reactivity with natural organic matter (NOM). Several studies have shown that combining ozone to MF/UF systems could minimize membrane fouling and getting higher operational fluxes. This work focused on ozone – ceramic membrane filtration for treating wastewater effluent and seawater. Effects of ozone as a pre – treatment or chemical cleaning with ceramic membrane filtration were identified in terms of permeate flux and organic fouling. Ozonation tests were done by adjusting O3 dose with source water, monitoring flux decline and membrane fouling. Backwashing availability and membrane recovery rate were also analyzed. Two types of MF/UF ceramics membranes (AAO and TAMI) were used for this study. When ozone dosage was higher in the source water, membrane filtration improved in performance, resulting in a reduced flux decline. In secondary wastewater effluent, raw source water declined up to 77% of normalized flux, while with O3 as pre – treatment, source water at its higher O3 dose, flux decreased only 33% of normalized flux. For seawater, membrane performance increase from declining to 37% of its final normalized flux to 21%, when O3 as a pre – treatment was used. Membrane recovery rate also improved even with low O3 dose, as an example, with 8 mg/L irreversible fouling decreases from 58% with no ozone addition to 29% for secondary wastewater effluent treatment. For seawater treatment, irreversible fouling decreased from 37% with no ozone addition to 21% at 8 mg/L, proving ozone is a

  1. Thermodynamic Assessment of the Y2o3-yb2o3-zro2 System

    Jacobson, Nathan S.; Liu, Zi-Kui; Kaufman, Larry; Zhang, Fan


    Yttria-zirconia (Y2O3-ZrO2) is the most widely used of the rare earth oxide-zirconia systems. There are numerous experimental studies of the phase boundaries in this system. In this paper, we assess these data and derive parameters for the solution models in this system. There is current interest in other rare earth oxide-zirconia systems as well as systems with several rare earth oxides and zirconia, which may offer improved properties over the Y2O3-ZrO2 system. For this reason, we also assess the ytterbia-zirconia (Yb2O3-ZrO2) and Y2O3-Yb2O3-ZrO2 system.

  2. Assessment of Ga2O3 technology


    architecture [60]. ....................................................................... 10 Figure 5: Photograph of 4-inch diameter Ga2O3 wafer...breakdown voltages can provide orders of magnitude reduction in system size, cost and weight. Figure 4: A More-Electric Aircraft (MEA) architecture [60...Technology base is narrowly located in Japan . Mainstream technology. Czochralski • Mature technology base. • Crucible-free crystal growth

  3. Posttranslational modification of Birch and Ragweed allergen proteins by common gas phase pollutants, NO2 and O3

    Mahmood, M. A.; Pope, F.; Bloss, W.


    The global incidence of hay fever has been rising for decades, however, the underlying reasons behind this rise remain unclear. It is hypothesized that exposure of pollen to common gas phase pollutants, such as nitrogen dioxide (NO2) and ozone (O3), increases the allergenicity of the pollen and thus increases hay fever incidence. Since atmospheric pollutants tend to have greater concentrations within urban areas (in particular NO2) the hypothesis suggests that greater allergenicity should occur in urban areas. Indeed, several studies do suggest higher hay fever incidence within urban areas compared to rural areas. Previous published work suggests a link between increased allergies with changes in the chemical composition of the pollen protein via posttranslational modification of the protein. This study investigates the posttranslational modification of two highly allergenic pollen species (Birch and Ragweed) that are common in Europe. Within the laboratory, we expose pollen grains to atmospherically relevant exposures of gas phase NO2, O3 and other common gas phase oxidants under a range of environmentally relevant conditions. The effects of the environmentally relevant exposures on the biochemistry of the pollen grains were probed using a proteomic approach (liquid chromatography coupled ultra-high resolution spectrometer). Our findings indicate the interaction between gas phase pollutants and pollen cause protein specific modifications; in particular, nitration occurs upon tyrosine residues and nitrosylation on cysteine residues. Possibly, these modifications may affect the immune response of the pollen protein, which may suggest a possible reason for increased allergies in reaction to such biologically altered protein. The laboratory-derived results will be supported with a time series analysis of asthma incidence rates for the London area, which take into account the pollen count, and pollutant concentrations. The implications of the results will be discussed

  4. The first-principles study of ferroelectric behaviours of PbTiO3/SrTiO3 and BaTiO3/SrTiO3 superlattices

    Zhu Zhen-Ye; Wang Biao; Wang Hai; Zheng Yue; Li Qing-Kun


    We have performed the first-principles calculation to investigate the origins of ferroelectricities and different polarization behaviours of superlattices BaTiO3/SrTiO3 and PbTiO3/SrTiO3- The density of state (DOS) and electronic charge profiles show that there are strong hybridizations between atoms Ti and O and between atoms Pb and O which play very important roles in producing the ferroelectricities of superlattices BaTiO3/rTiO3 and PbTiO3/SrTiO3. Owing to the decline of internal electric field in SrTiO3 (ST) layer, the tetragonality and polarizations of superlattices decrease with increasing the fraction of SrTiO3 in the superlattices. We find that the polarization of PbTiO3/SrTiO3 is largerthan that of BaTiO3/SrTiO3 at the same ratio of components, because the polarization mismatch between PbTiO3 and SrTiO3 is larger than that between BaTiO3 and SrTiO3. The polarization and tetragonality are enhanced with respect to those of bulk tetragonal BaTiO3 in the superlattices BaTiO3/SrTiO3, while the polarization and tetragonality are reduced with respect to those of bulk tetragonal PbTiO3 in superlattices PbTiO3/SrTiO3.

  5. Limited effect of ozone reductions on the 20-year photosynthesis trend at Harvard forest.

    Yue, Xu; Keenan, Trevor F; Munger, William; Unger, Nadine


    Ozone (O3 ) damage to leaves can reduce plant photosynthesis, which suggests that declines in ambient O3 concentrations ([O3 ]) in the United States may have helped increase gross primary production (GPP) in recent decades. Here, we assess the effect of long-term changes in ambient [O3 ] using 20 years of observations at Harvard forest. Using artificial neural networks, we found that the effect of the inclusion of [O3 ] as a predictor was slight, and independent of O3 concentrations, which suggests limited high-frequency O3 inhibition of GPP at this site. Simulations with a terrestrial biosphere model, however, suggest an average long-term O3 inhibition of 10.4% for 1992-2011. A decline of [O3 ] over the measurement period resulted in moderate predicted GPP trends of 0.02-0.04 μmol C m(-2)  s(-1)  yr(-1) , which is negligible relative to the total observed GPP trend of 0.41 μmol C m(-2)  s(-1)  yr(-1) . A similar conclusion is achieved with the widely used AOT40 metric. Combined, our results suggest that ozone reductions at Harvard forest are unlikely to have had a large impact on the photosynthesis trend over the past 20 years. Such limited effects are mainly related to the slow responses of photosynthesis to changes in [O3 ]. Furthermore, we estimate that 40% of photosynthesis happens in the shade, where stomatal conductance and thus [O3 ] deposition is lower than for sunlit leaves. This portion of GPP remains unaffected by [O3 ], thus helping to buffer the changes of total photosynthesis due to varied [O3 ]. Our analyses suggest that current ozone reductions, although significant, cannot substantially alleviate the damages to forest ecosystems. © 2016 John Wiley & Sons Ltd.

  6. Ozone Treatment of Animal Manure for Odor Control

    Fahad N. Alkoaik


    Full Text Available Problem statement: The effectiveness of ozone in reducing odor emission from liquid animal manure was evaluated under batch and continuous treatment operations. Results: The results indicated that the use of ozone for the treatment of animal manure proved to be effective in reducing the odor offensiveness. A minimum 3.4 level out of 10 (66% reduction was achieved in the continuous operation; while a minimum of 3.1 (69% reduction was achieved in the batch operation. Increasing the level of ozone (O3 increased the level of offensiveness which was attributed to the presence of intermediate products due to the interaction between ozone and hydrogen sulfide and methylamine. Conclusion: The cost analysis indicated that the treatment is economical as a ton of manure could be treated at a cost of $ 0.23.

  7. Tropospheric ozone and its regional transport over Cape Town

    Nzotungicimpaye, Claude-Michel; Abiodun, Babatunde J.; Steyn, Douw G.


    As part of efforts to understand the sources of air pollution in Cape Town, this study investigates the local variation of tropospheric ozone (O3) and identifies possible advection paths of O3 pollution from a remote source to Cape Town. Measurements of O3 and wind from three sites in the Cape Town area were analyzed to study the local variations of O3. At each site, the diurnal variation of O3 is found to be mainly driven by photochemical production while the seasonal variation of O3 is mostly driven by wind conditions. The highest concentration of O3 is observed at the remote site (Cape Point) while lowest O3 concentration is observed at the sub-urban site (Goodwood), where there are chemical sinks of O3 such as NOx. Atmospheric pollution over southern Africa was simulated to study the regional transport of O3. The simulations show that extreme O3 levels in Cape Town can be caused by air pollution transported from the industrial Highveld of South Africa, in the lower troposphere. Such extreme O3 pollution events over Cape Town are simulated to occur in January (14%), March (44%), April (28%) and September (14%). Lagrangian trajectories suggest four paths by which air parcels can be transported from the industrial Highveld to Cape Town: a north-easterly path which is the most frequent route, a tropical deviation route, a deviation along the south coastline and an oceanic deviation path which is the less frequent route. The major advection paths associated with poor air quality in Cape Town are the north-easterly route and the path along the south coastline of the country. Hence the study suggests that emissions in the industrial Highveld may contribute to O3 concentration in the Cape Town area.

  8. Monitoring and future projections of the Antarctic Ozone Hole using the new Ozone Mapping and Profiler Suite (OMPS)

    Kramarova, N. A.; Newman, P. A.; Nash, E. R.; Bhartia, P. K.; McPeters, R. D.; Rault, D. F.; Seftor, C. J.; Xu, P.


    Using the new Ozone Mapping and Profiler Suite (OMPS), launched October 2011 on board the Suomi National Polar-orbiting Partnership satellite, we have studied the structure and evolution of the 2012 and 2013 ozone holes. The 1st ozone hole observations by OMPS began in 2012. We quality check the OMPS measurements by comparing to other satellite instruments (Aura MLS, OMI and SBUV) and ozone sonde balloon measurements. The comparisons reveal that OMPS is producing excellent Antarctic ozone hole information, and, thus, OMPS data can be used to continue the historical record of Antarctic ozone observations. In 2012 the ozone hole developed quite normally in the August to-late September 2012 period, but disappeared much more rapidly during the late-September to November period than it would be expected in a normal year. This resulted in the second weakest ozone hole observed since 1988. Some have suggested that the rapid 2012 disappearance is evidence that the Montreal Protocol is working. However, the development of the ozone hole in August and September is largely driven by chlorine and bromine from human-produced compounds, and the normal development of the ozone hole in August-September 2012 suggests that chlorine and bromine levels were roughly the same as previous years. At the same time, observations from meteorological data show that there were stronger than average weather systems, faster warming during the September -November period, and stronger vertical motions, that led to a rapid decay of the 2012 ozone hole. Hence, the weak ozone hole of 2012 is not evidence that the Montreal Protocol has impacted the ozone hole. The characteristics of the 2013 ozone hole, as observed by OMPS, will also be shown in the presentation. Model predictions suggest that the ozone hole will begin showing signs of recovery in about 2018, and it will be fully recovered back to 1980 levels in about 2065. We will update projections of the ozone hole recovery using a parametric model

  9. Variation of surface ozone exceedance around Klang Valley, Malaysia

    Ahamad, Fatimah; Latif, Mohd Talib; Tang, Rosy; Juneng, Liew; Dominick, Doreena; Juahir, Hafizan


    The total hourly surface ozone (O3) exceedance from the 100 ppbv hourly O3 standard set by the Department of Environment Malaysia (DOE) was analysed, as elevated O3 concentrations pose health risks to humans and harms vegetation. Air quality data from 2008 to 2010 were obtained from a total of seven stations located around the west coast of Peninsular Malaysia. Cheras and Shah Alam monitoring stations consistently showed a high frequency of noncompliance to the DOE standards. Hierarchical Agglomerative Cluster Analysis (HACA) was performed on the daily maximum O3 concentration to analyse the spatial variability. Three distinct clusters were obtained from HACA runs on the daily maximum O3 and the results reflected O3 exceedance pattern among the stations. Analysis of the monthly average O3, nitrogen oxide (NO), and nitrogen dioxide (NO2) concentrations indicated a strong localised influence on the O3 exceedance patterns. It can be concluded that the O3 exceedance pattern in the Klang Valley area is strongly influenced by local pollutant emission and dispersion characteristics.

  10. Tests of stratospheric models - The reactions of atomic chlorine with O3 and CH4 at low temperature

    Demore, W. B.


    The rate-constant ratio of the photochemical reactions of atomic chlorine with O3 and CH4 was determined using data from laboratory experiments on competitive chlorination of O3/CH4 mixtures at stratospheric temperatures (197-217 K). Two experimental approaches were used: (1) measuring the k1/k2 ratio for the reactions of atomic chlorine with ozone and methane and (2) testing for some of the ClO/CH3O2 chemistry. The chlorine and ozone concentrations were monitored by UV-Vis spectroscopy, and the CH3Cl concentration was measured by FTIR. The results on the k1/k2 ratio are in excellent agreement with the current NASA recommendation (DeMore et al., 1990), being only 12 percent higher. On the other hand, results on the ClO + CH3O2 reaction do not support the rate constant suggested by Simon et al. (1989).

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

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


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

  12. Relationship of surface O3 to large-scale circulation patterns during two recent winters

    Mao, Huiting; Talbot, Robert


    We demonstrate a direct connection between large-scale circulation patterns and surface O3 using atmospheric observations obtained during winters 2002 and 2003. Measurements at two rural sites in the northeastern U.S. revealed that median mixing ratios of O3 in winter 2003 were increased by up to 80% compared to 2002, and greatly exceeded previous spring annual maximums. To explain this we propose that strong meridional flows in winter 2003 frequently transported O3-rich mid-tropospheric air masses from high latitudes to the northeastern U.S. while cooling regional climate 4.4°C below normal. Our measurements also show that an exceptionally elevated spring O3 maximum occurred in 2003. The impact from this winter enhancement on the levels of O3 and other species during the following months will be largely driven by actual climatic conditions.

  13. Electron-relaxation-mode interaction in BaTiO3:Nb

    Maglione, M.; Belkaoumi, M.


    Dielectric relaxation was previously reported in BaTiO3 and BaTiO3:Fe single crystals at radio frequencies [M. Maglione et al., Phys. Rev. B 40, 11 441 (1989)]. We have measured the dielectric dispersion in four BaTiO3:Nb samples (xNb<0.3 at. %) as a function of frequency (10O3:Nb enhances drastically the relaxation step at all temperatures. In the rhombohedral phase of BaTiO3:Nb (T<180 K), an unusual slowing down of the relaxation motion is measured. The relaxation time increases to more than 10-2 s at 20 K while the relaxation step is temperature independent. The precursor effect of this slowing down is a maximum in the dc conductivity. A simple electron-relaxation-mode coupling model may explain such behavior.

  14. Preparation of α-Fe2O3 Nanodisks by Blocking the Growth of (001) Plane

    Baoliang Lv; Yao Xu; Dong Wu; Yuhan Sun


    Based on the difference of hydroxy group configuration on different planes of α-Fe2O3 nanoparticles, using the special adsorption and coordination of phosphate on the (001) plane of α-Fe2O3, well-crystallized and well dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm and thickness of 40-80 nm were synthesized via a hydrothermal method. The magnetic properties of synthesized nanodisks were investigated. It was found that the nanodisks possessed a saturation magnetization (Ms) of 0.38 emu/g, a remanent magnetization (Mr) of 0.031 emu/g and a coercivity of 452.91 Oe at room temperature. The Mr and coercivity of synthesized α-Fe2O3 nanodisks are higher and the Ms is lower than those of other previously reported α-Fe2O3 nanostructures.

  15. Elevated ozone alters soybean-virus interaction.

    Bilgin, Damla D; Aldea, Mihai; O'Neill, Bridget F; Benitez, Marisol; Li, Min; Clough, Steven J; DeLucia, Evan H


    Increasing concentrations of ozone (O(3)) in the troposphere affect many organisms and their interactions with each other. To analyze the changes in a plant-pathogen interaction, soybean plants were infected with Soybean mosaic virus (SMV) while they were fumigated with O(3). In otherwise natural field conditions, elevated O(3) treatment slowed systemic infection and disease development by inducing a nonspecific resistance against SMV for a period of 3 weeks. During this period, the negative effect of virus infection on light-saturated carbon assimilation rate was prevented by elevated O(3) exposure. To identify the molecular basis of a soybean nonspecific defense response, high-throughput gene expression analysis was performed in a controlled environment. Transcripts of fungal, bacterial, and viral defense-related genes, including PR-1, PR-5, PR-10, and EDS1, as well as genes of the flavonoid biosynthesis pathways (and concentrations of their end products, quercetin and kaempherol derivatives) increased in response to elevated O(3). The drastic changes in soybean basal defense response under altered atmospheric conditions suggest that one of the elements of global change may alter the ecological consequences and, eventually, coevolutionary relationship of plant-pathogen interactions in the future.

  16. Degradation of thiamethoxam and metoprolol by UV, O3 and UV/O3 hybrid processes: Kinetics, degradation intermediates and toxicity

    Šojić, D.; Despotović, V.; Orčić, D.; Szabó, E.; Arany, E.; Armaković, S.; Illés, E.; Gajda-Schrantz, K.; Dombi, A.; Alapi, T.; Sajben-Nagy, E.; Palágyi, A.; Vágvölgyi, Cs.; Manczinger, L.; Bjelica, L.; Abramović, B.


    SummaryA comprehensive study of the degradation of thiamethoxam (THIA) and metoprolol (MET) was conducted by using UV-induced photolysis (λ = 254 nm), ozonation, and a combination of these methods. In order to investigate how molecular structure of the substrate influences the rate of its degradation, we compared these three processes for the insecticide THIA and the drug MET (a β1-blocker). Of the three treatments applied, the UV photolysis and the combination of UV/O3 were found to be most effective in the degradation of THIA, while the UV/O3 process appeared to be the most efficient in terms of MET decay. The degradation kinetics was monitored by LC-DAD, and spectrophotometry, while the mineralization of the substrates was studied by TOC analysis. Reaction intermediates were studied in detail and a number of them were identified using LC-MS (ESI+/ESI-). Both parent compounds showed slight toxic effects towards algae Pseudokirchneriella subcapitata and bacteria Vibrio fischeri. However, the toxicity of the solutions containing also the degradation intermediates appeared to be much higher for all the test organisms. The inhibition/mortality rates were reduced most efficiently by the UV/O3 procedure. Ames test and Comet assay were used to follow the genotoxicity during the degradation of the studied compounds. Genotoxic intermediates were frequently detected in the case of MET in the UV treatment alone or in the presence of ozone. Treatments of THIA samples resulted less frequently in genotoxic intermediates. To our best knowledge, this work is the first genotoxicological investigation dealing with the photolytic degradation process of the studied compounds.

  17. Raman and Fluorescence Spectroscopy of CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7

    Jianlan Cui


    Full Text Available To better understand and ascertain the mechanisms of flotation reagent interaction with rare earth (RE minerals, it is necessary to determine the physical and chemical properties of the constituent components. Seven rare earth oxides (CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7 that cover the rare earth elements (REEs from light to heavy REEs have been investigated using Raman spectroscopy. Multiple laser sources (wavelengths of 325 nm, 442 nm, 514 nm, and 632.8 nm for the Raman shift ranges from 100 cm−1 to 5000 cm−1 of these excitations were used for each individual rare earth oxide. Raman shifts and fluorescence emission have been identified. Theoretical energy levels for Er, Nd, and Yb were used for the interpretation of fluorescence emission. The experimental results showed good agreement with the theoretical calculation for Er2O3 and Nd2O3. Additional fluorescence emission was observed with Yb2O3 that did not fit the reported energy level diagram. Tb4O7 was observed undergoing laser induced changes during examination.

  18. Ground-level ozone differentially affects nitrogen acquisition and allocation in mature European beech (Fagus sylvatica) and Norway spruce (Picea abies) trees.

    Weigt, R B; Häberle, K H; Millard, P; Metzger, U; Ritter, W; Blaschke, H; Göttlein, A; Matyssek, R


    Impacts of elevated ground-level ozone (O(3)) on nitrogen (N) uptake and allocation were studied on mature European beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.) in a forest stand, hypothesizing that: (i) chronically elevated O(3) limits nutrient uptake, and (ii) beech responds more sensitively to elevated O(3) than spruce, as previously found for juvenile trees. Tree canopies were exposed to twice-ambient O(3) concentrations (2 × O(3)) by a free-air fumigation system, with trees under ambient O(3) serving as control. After 5 years of O(3) fumigation, (15)NH(4)(15)NO(3) was applied to soil, and concentrations of newly acquired N (N(labelled)) and total N (N(total)) in plant compartments and soil measured. Under 2 × O(3), N(labelled) and N(total) were increased in the bulk soil and tended to be lower in fine and coarse roots of both species across the soil horizons, supporting hypothesis (i). N(labelled) was reduced in beech foliage by up to 60%, and by up to 50% in buds under 2 × O(3). Similarly, N(labelled) in stem bark and phloem was reduced. No such reduction was observed in spruce, reflecting a stronger effect on N acquisition in beech in accordance with hypothesis (ii). In spruce, 2 × O(3) tended to favour allocation of new N to foliage. N(labelled) in beech foliage correlated with cumulative seasonal transpiration, indicating impaired N acquisition was probably caused by reduced stomatal conductance and, hence, water transport under elevated O(3). Stimulated fine root growth under 2 × O(3) with a possible increase of below-ground N sink strength may also have accounted for lowered N allocation to above-ground organs. Reduced N uptake and altered allocation may enhance the use of stored N for growth, possibly affecting long-term stand nutrition.

  19. Effects of elevated pO3 on carbon cycle between above and belowground organs of trees

    LIU Xi-ping; Rennenberg Heinz; Matyssek Rainer


    Translocation of carbohydrate from leaves to roots via phloem and reallocation from roots to leaves via xylem regulate the allocation of carbon (C) between above and belowground organs of trees. To quantitatively analyze effects of elevated ozone concentrations pO3 on the internal cycle of C, juvenile beech and spruce were grown in phytotrons and exposed to ambient and elevated pO3 (i.e. twice-ambient O3 levels, restricted to < 150 ppb) for two growing seasons. The translocation of C in the phloem and xylem was quantitatively studied by investigating the phloem/xylem-loading of sugars, the differentiation of stem conductive tissue and the hourly water flow through the stem. Results in the present study shown, elevated pO3 significantly decreased C translocation from shoot to roots in beech by reducing both sugar concentration in the phloem and conductive phloem area. Elevated pO3 also significantly decreased C reallocation from the roots to the shoot in beech by reducing both of sugar concentration in the xylem and transpiration rate. The adverse effects of elevated pO3 on C translocation in the phloem and xylem, however, were small in spruce.Contrasting to beech, spruce is less sensitive to elevated pO3, regarding to phloem differentiation and sugar concentrations in the phloem and xylem.

  20. Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices

    Wei, Haoming; Barzola-Quiquia, Jose Luis; Yang, Chang; Patzig, Christian; Höche, Thomas; Esquinazi, Pablo; Grundmann, Marius; Lorenz, Michael


    High-quality lattice-matched LaNiO3/LaMnO3 superlattices with monolayer terrace structure have been grown on both (111)- and (001)-oriented SrTiO3 substrates by pulsed laser deposition. In contrast to the previously reported experiments, a magnetic exchange bias is observed that reproducibly occurs in both (111)- and (001)-oriented superlattices with the thin single layers of 5 and 7 unit cells, respectively. The exchange bias is theoretically explained by charge transfer-induced magnetic moments at Ni atoms. Furthermore, magnetization data at low temperature suggest two magnetic phases in the superlattices, with Néel temperature around 10 K. Electrical transport measurements reveal a metal-insulator transition with strong localization of electrons in the superlattices with the thin LaNiO3 layers of 4 unit cells, in which the electrical transport is dominated by two-dimensional variable range hopping.

  1. Oxygen evolution on a SrFeO3 anode - Mechanistic considerations from molecular orbital theory

    Mehandru, S. P.; Anderson, Alfred B.


    Various pathways proposed in the literature for the evolution of O2 in electrochemical oxidations are explored using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory and the cluster models of the SrFeO3 surface as a prototype material. Calculations indicate that oxygen atoms can be easily formed on the (100) surface as well as on the edge cation sites of a SrFeO3 anode by the discharge of OH(-), followed by its deprotonation and electron transfer to the electrode. The O atoms can form O2 on the edge and corner sites, where the Fe(4+) is coordinated to four and three bulk oxygen anions, respectively. The calculations strongly disfavor mechanisms involving coupling of oxygen atoms adsorbed on different cations as well as a mechanism featuring an ozone intermediate.

  2. High troposphere O3 filament at mid-latitude: a BORTAS campaign case study

    Aruffo, Eleonora; Peterson, David; Di Carlo, Piero; Biancofiore, Fabio; Busilacchio, Marcella; Dari Salisburgo, Cesare; Giammaria, Franco; Bauguitte, Stephane; Lee, James; Moller, Sarah; Hopkins, James; Punjabi, Shalini; Lewis, Alistair C.; Palmer, Paul; Hyer, Edward


    During a flight (B625, 24 July 2011) of the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites, Nova Scotia, Canada, July-August 2011), an increase in the ozone (O3) concentrations has been observed at high altitude (about 7.5 Km a.s.l.) correlated with a significant growth of total peroxy nitrates (∑PNs), CO, NO2, NOy, black carbon (BC), isoprene and other species. We will illustrate the data analysis, the Hysplit back trajectories calculation and the analysis of the meteorological/physical conditions occurred during this case study in order to demonstrate that the O3 filament measured at high altitude over the Atlantic Ocean (between Nova Scotia and the Gulf of St. Lawrence) is a consequence of boreal biomass burning fires.

  3. Evaluation of the effects of ozone on yield of Japanese rice (Oryza sativa L.) based on stomatal ozone uptake.

    Yamaguchi, Masahiro; Hoshino, Daiki; Inada, Hidetoshi; Akhtar, Nahid; Sumioka, Chika; Takeda, Kenta; Izuta, Takeshi


    To evaluate the negative impact of ozone (O3) on Japanese crop plant yield based on cumulative stomatal O3 flux, a Japanese rice cultivar, Koshihikari, was exposed to O3 in O3-exposure chambers. Stomatal diffusive conductance to water vapour were measured during the experimental period. We parameterized and improved a stomatal diffusive conductance model by considering seasonal changes in stomatal diffusive conductance, as well as the acute effects of O3 on this variable. Our adjusted model accounted for 64% of the variation within the data set. Based on the results of linear regression analyses of the relationship between relative yield and cumulative O3 uptake, the negative impact of O3 on the yield of Koshihikari can be evaluated using cumulative O3 uptake with a threshold of 10 nmol O3 m(-2) projected leaf area s(-1) and an integration period of -300 to 100 °C days from anthesis.

  4. Analysis of tropospheric ozone and carbon monoxide profiles over South America based on MOZAIC/IAGOS database and model simulations

    Marcia A. Yamasoe


    Full Text Available We analysed ozone and carbon monoxide profiles measured by commercial aircrafts from the MOZAIC/IAGOS fleet, during ascending and descending flights over Caracas, in Venezuela, from August 1994 to December 2009, over Rio de Janeiro, from 1994 to 2004 and from July 2012 to June 2013, and over São Paulo, in Brazil, from August 1994 to 2005. For ozone, results showed a clean atmosphere over Caracas presenting the highest seasonal mean in March, April and May. Backward trajectory analyses with FLEXPART, of case studies for which the measured concentrations were high, showed that contributions from local, Central and North America, the Caribbean and Africa either from anthropogenic emissions, biomass burning or lightning were possible. Satellite products as fire counts from MODIS, lightning flash rates from LIS, and CO and O3 from Infrared Atmospheric Sounding Interferometer and wind maps at different levels helped corroborate previous findings. Sensitivity studies performed with the chemical transport model GEOS-Chem captured the effect of anthropogenic emissions but underestimated the influence of biomass burning, which could be due to an underestimation of GFEDv2 emission inventory. The model detected the contribution of lightning from Africa in JJA and SON and from South America in DJF, possibly from the northeast of Brazil. Over São Paulo and Rio de Janeiro, GEOS-Chem captured the seasonal variability of lightning produced in South America and attributed this source as the most important in this region, except in JJA, when anthropogenic emissions were addressed as the more impacting source of ozone precursors. However, comparison with the measurements indicated that the model overestimated ozone formation, which could be due to the convective parameterisation or the stratospheric influence. The highest ozone concentration was observed during September to November, but the model attributed only a small influence of biomass burning from South

  5. Source apportionment of surface ozone in the Yangtze River Delta, China in the summer of 2013

    Li, L.; An, J. Y.; Shi, Y. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Wang, H. L.; Lou, S. R.; Wang, Q.; Lu, Q.; Wu, J.


    We applied ozone source apportionment technology (OSAT) with tagged tracers coupled within the Comprehensive Air Quality Model with Extensions (CAMx) to study the region and source category contribution to surface ozone in the Yangtze River Delta area in summer of 2013. Results indicate that the daytime ozone concentrations in the YRD region are influenced by emissions both locally, regionally and super-regionally. At urban Shanghai, Hangzhou and Suzhou receptors, the ozone formation is mainly VOC-limited, precursor emissions form Zhejiang province dominate their O3 concentrations. At the junction area among two provinces and Shanghai city, the ozone is usually influenced by all the three areas. The daily max O3 at the Dianshan Lake in July are contributed by Zhejiang (48.5%), Jiangsu (11.7%), Anhui (11.6%) and Shanghai (7.4%), long-range transport constitutes around 20.9%. At Chongming site, the BVOC emissions rate is higher than urban region. Regional contribution results show that Shanghai constitutes 15.6%, Jiangsu contributes 16.2% and Zhejiang accounts for 25.5% of the daily max O3. The analysis of the source category contribution to high ozone in the Yangtze River Delta region indicates that the most significant anthropogenic emission source sectors contributing to O3 pollution include industry, vehicle exhaust, although the effects vary with source sector and selected pollution episodes. Emissions of NOx and VOCs emitted from the fuel combustion of industrial boilers and kilns, together with VOCs emissions from industrial process contribute a lot to the high concentrations in urban Hangzhou, Suzhou and Shanghai. The contribution from regional elevated power plants cannot be neglected, especially to Dianshan Lake. Fugitive emissions of volatile pollution sources also have certain contribution to regional O3. These results indicate that the regional collaboration is of most importance to reduce ambient ozone pollution, particularly during high ozone episodes.

  6. Impacts of rising tropospheric ozone on photosynthesis and metabolite levels on field grown soybean.

    Sun, Jindong; Feng, Zhaozhong; Ort, Donald R


    The response of leaf photosynthesis and metabolite profiles to ozone (O3) exposure ranging from 37 to 116 ppb was investigated in two soybean cultivars Dwight and IA3010 in the field under fully open-air conditions. Leaf photosynthesis, total non-structural carbohydrates (TNC) and total free amino acids (TAA) decreased linearly with increasing O3 levels in both cultivars with average decrease of 7% for an increase in O3 levels by 10 ppb. Ozone interacted with developmental stages and leaf ages, and caused higher damage at later reproductive stages and in older leaves. Ozone affected yield mainly via reduction of maximum rate of Rubisco carboxylation (Vcmax) and maximum rates of electron transport (Jmax) as well as a shorter growing season due to earlier onset of canopy senescence. For all parameters investigated the critical O3 levels (∼50 ppb) for detectable damage fell within O3 levels that occur routinely in soybean fields across the US and elsewhere in the world. Strong correlations were observed in O3-induced changes among yield, photosynthesis, TNC, TAA and many metabolites. The broad range of metabolites that showed O3 dose dependent effect is consistent with multiple interaction loci and thus multiple targets for improving the tolerance of soybean to O3.

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

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


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

  8. Downward transport of ozone rich air and implications for atmospheric chemistry in the Amazon rainforest

    Gerken, Tobias; Wei, Dandan; Chase, Randy J.; Fuentes, Jose D.; Schumacher, Courtney; Machado, Luiz A. T.; Andreoli, Rita V.; Chamecki, Marcelo; Ferreira de Souza, Rodrigo A.; Freire, Livia S.; Jardine, Angela B.; Manzi, Antonio O.; Nascimento dos Santos, Rosa M.; von Randow, Celso; dos Santos Costa, Patrícia; Stoy, Paul C.; Tóta, Julio; Trowbridge, Amy M.


    From April 2014 to January 2015, ozone (O3) dynamics were investigated as part of GoAmazon 2014/5 project in the central Amazon rainforest of Brazil. Just above the forest canopy, maximum hourly O3 mixing ratios averaged 20 ppbv (parts per billion on a volume basis) during the June-September dry months and 15 ppbv during the wet months. Ozone levels occasionally exceeded 75 ppbv in response to influences from biomass burning and regional air pollution. Individual convective storms transported O3-rich air parcels from the mid-troposphere to the surface and abruptly enhanced the regional atmospheric boundary layer by as much as 25 ppbv. In contrast to the individual storms, days with multiple convective systems produced successive, cumulative ground-level O3 increases. The magnitude of O3 enhancements depended on the vertical distribution of O3 within storm downdrafts and origin of downdrafts in the troposphere. Ozone mixing ratios remained enhanced for > 2 h following the passage of storms, which enhanced chemical processing of rainforest-emitted isoprene and monoterpenes. Reactions of isoprene and monoterpenes with O3 are modeled to generate maximum hydroxyl radical formation rates of 6 × 106 radicals cm-3s-1. Therefore, one key conclusion of the present study is that downdrafts of convective storms are estimated to transport enough O3 to the surface to initiate a series of reactions that reduce the lifetimes of rainforest-emitted hydrocarbons.

  9. Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar.

    Yuan, Xiangyang; Calatayud, Vicent; Gao, Feng; Fares, Silvano; Paoletti, Elena; Tian, Yuan; Feng, Zhaozhong


    The combined effects of ozone (O3 ) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal-filtered air, CF, and non-filtered air +40 ppb, E-O3 ) and soil water stress (well-watered, WW, and mild drought, MD, one-third irrigation) for 96 days. Consistent with light-saturated photosynthesis (Asat ), intercellular CO2 concentration (Ci ) and chlorophyll content, isoprene emission depended on drought, O3 , leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (-40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th-15th from the apex) than in upper leaves (6th-8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up-scaled to the entire-plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E-O3 . Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality.

  10. Effect of cloud-to-ground lightning and meteorological conditions on surface NOx and O3 in Hong Kong

    Fei, Leilei; Chan, L. Y.; Bi, Xinhui; Guo, Hai; Liu, Yonglin; Lin, Qinhao; Wang, Xinming; Peng, Ping'an; Sheng, Guoying


    Cloud-to-ground (CG) lightning, meteorological conditions and corresponding surface nitrogen oxides (NOx) and ozone (O3) variations in relation to thunderstorm and lightning activities over Hong Kong at Kwai Chung (urban), Tung Chung (new town) and Tap Mun (background) during active lightning seasons from 2009 to 2013 were studied by analyzing respective air quality monitoring station data along with CG lightning and meteorological data. We observed NOx enhancement and significant O3 decline on lightning days. Influences of land use types, lightning activities and meteorological conditions on surface NOx and O3 were examined. NOx and O3 concentrations shifted towards higher and lower levels, respectively, during lightning days especially in the dominant wind directions. Principal component analysis/absolute principal component scores (PCA/APCS) method and stepwise multiple linear regression (MLR) analysis were employed to examine the influence of thunderstorm related lightning and meteorological parameters on surface NOx and O3. Wind speed was supposed to be the most important meteorological parameter affecting the concentration of NOx, and lightning activities were observed to make a positive contribution to NOx. Negative contribution of hot, cloudy and wet weather and positive contribution of wind speed were found to affect the concentration of O3. Lightning parameters were also found to make a small positive contribution to O3 concentration at Tap Mun and Tung Chung, but the net effect of lightning activities and corresponding meteorological conditions was the decrease of O3 on lightning days. Reasonably good agreement between the predicted and observed NOx and O3 values indicates that PCA/APCS-MLR is a valuable method to study the thunderstorm induced NOx and O3 variations.

  11. Distinct responses of soil microbial communities to elevated CO2 and O3 in a soybean agro-ecosystem.

    He, Zhili; Xiong, Jinbo; Kent, Angela D; Deng, Ye; Xue, Kai; Wang, Gejiao; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong


    The concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have been rising due to human activities. However, little is known about how such increases influence soil microbial communities. We hypothesized that elevated CO2 (eCO2) and elevated O3 (eO3) would significantly affect the functional composition, structure and metabolic potential of soil microbial communities, and that various functional groups would respond to such atmospheric changes differentially. To test these hypotheses, we analyzed 96 soil samples from a soybean free-air CO2 enrichment (SoyFACE) experimental site using a comprehensive functional gene microarray (GeoChip 3.0). The results showed the overall functional composition and structure of soil microbial communities shifted under eCO2, eO3 or eCO2+eO3. Key functional genes involved in carbon fixation and degradation, nitrogen fixation, denitrification and methane metabolism were stimulated under eCO2, whereas those involved in N fixation, denitrification and N mineralization were suppressed under eO3, resulting in the fact that the abundance of some eO3-supressed genes was promoted to ambient, or eCO2-induced levels by the interaction of eCO2+eO3. Such effects appeared distinct for each treatment and significantly correlated with soil properties and soybean yield. Overall, our analysis suggests possible mechanisms of microbial responses to global atmospheric change factors through the stimulation of C and N cycling by eCO2, the inhibition of N functional processes by eO3 and the interaction by eCO2 and eO3. This study provides new insights into our understanding of microbial functional processes in response to global atmospheric change in soybean agro-ecosystems.

  12. Chemistry of the Fe2O3/BiFeO3 Interface in BiFeO3 Thin Film Heterostructures

    Valanoor Nagarajan


    Full Text Available We investigate the interfacial chemistry of secondary Fe2O3 phases formed in a BiFeO3 (BFO layer in BFO/ La0.67Sr0.33MnO3 (LSMO/SrTiO3 (STO heterostructures. A combination of high-resolution spherical aberration corrected scanning TEM and spectroscopy results, reveals that specific chemical and crystallographic similarities between Fe2O3 and BFO, enable the BFO layer to form a facile host for Fe2O3.

  13. Research on Y2O3:Eu Phosphor Coated with In2O3


    Y2O3:Eu red phosphor for FED application was prepared by high temperature solid-state reaction. The In2O3 coating by precipitation method to the phosphor was applied and the analyses of XRD, Zeta potential, SEM, EDS and low voltage cathodoluminescence (CL) were conducted for investigating the coating effect. The results showed that In2O3 coating promoted the low voltage CL of the phosphor efficiently. The promotion was possibly due to the enhancement of the surface conductivity of the phosphor grains.

  14. Fate of bulk and trace organics during a simulated aquifer recharge and recovery (ARR)-ozone hybrid process.

    Yoon, Min K; Drewes, Jörg E; Amy, Gary L


    The attenuation of bulk organic matter and trace organic contaminants (TOrCs) was evaluated for various aquifer recharge and recovery (ARR)-ozone (O3) hybrid treatment process combinations using soil-batch reactor and bench-scale ozonation experiments as a proof of concept prior to pilot and/or field studies. In water reclamation and especially potable reuse, refractory bulk organic matter and TOrCs are of potential health concern in recycled waters. In this study, the role of biotransformation of bulk organic matter and TOrCs was investigated considering different simulated treatment combinations, including soil passage (ARR) alone, ARR after ozonation (O3-ARR), and ARR prior to ozonation (ARR-O3). During oxic (aerobic) ARR simulations, soluble microbial-like substances (e.g., higher molecular weight polysaccharides and proteins) were easily removed while (lower molecular weight) humic substances and aromatic organic matter were not efficiently removed. During ARR-ozone treatment simulations, removals of bulk organic matter and TOrCs were rapid and effective compared to ARR alone. A higher reduction of effluent-derived organic matter, including aromatic organic matter and humic substances, was observed in the ARR-O3 hybrid followed by the O3-ARR hybrid. An enhanced attenuation of recalcitrant TOrCs was observed while increasing the ozone dose slightly (O3: DOC=1). TOrC removal efficiency also increased during the post-ozone treatment combination (i.e., ARR-O3). In addition, the carcinogenic wastewater disinfection byproduct N-nitrosodimethylamine (NDMA) was eliminated below the method reporting limit (<5 ng L(-1)) both during ARR treatment alone and the ARR-ozone hybrid.

  15. Fate of bulk and trace organics during a simulated aquifer recharge and recovery (ARR)-ozone hybrid process

    Yoon, Min


    The attenuation of bulk organic matter and trace organic contaminants (TOrCs) was evaluated for various aquifer recharge and recovery (ARR)-ozone (O3) hybrid treatment process combinations using soil-batch reactor and bench-scale ozonation experiments as a proof of concept prior to pilot and/or field studies. In water reclamation and especially potable reuse, refractory bulk organic matter and TOrCs are of potential health concern in recycled waters. In this study, the role of biotransformation of bulk organic matter and TOrCs was investigated considering different simulated treatment combinations, including soil passage (ARR) alone, ARR after ozonation (O3-ARR), and ARR prior to ozonation (ARR-O3). During oxic (aerobic) ARR simulations, soluble microbial-like substances (e.g., higher molecular weight polysaccharides and proteins) were easily removed while (lower molecular weight) humic substances and aromatic organic matter were not efficiently removed. During ARR-ozone treatment simulations, removals of bulk organic matter and TOrCs were rapid and effective compared to ARR alone. A higher reduction of effluent-derived organic matter, including aromatic organic matter and humic substances, was observed in the ARR-O3 hybrid followed by the O3-ARR hybrid. An enhanced attenuation of recalcitrant TOrCs was observed while increasing the ozone dose slightly (O3: DOC=1). TOrC removal efficiency also increased during the post-ozone treatment combination (i.e., ARR-O3). In addition, the carcinogenic wastewater disinfection byproduct N-nitrosodimethylamine (NDMA) was eliminated below the method reporting limit (<5ngL-1) both during ARR treatment alone and the ARR-ozone hybrid. © 2013 Elsevier Ltd.

  16. Observation of enhanced ozone in an electrically active storm over Socorro, NM: Implications for ozone production from corona discharges

    Minschwaner, K.; Kalnajs, L. E.; Dubey, M. K.; Avallone, L. M.; Sawaengphokai, P. C.; Edens, H. E.; Winn, W. P.


    Enhancements in ozone were observed between about 3 and 10 km altitude within an electrically active storm in central New Mexico. Measurements from satellite sensors and ground-based radar show cloud top pressures between 300 and 150 mb in the vicinity of an ozonesonde launched from Socorro, NM, and heavy precipitation with radar reflectivities exceeding 50 dBZ. Data from a lightning mapping array and a surface electric field mill show a large amount of electrical activity within this thunderstorm. The observed ozone enhancements are large (50% above the mean) and could have resulted from a number of possible processes, including the advection of polluted air from the urban environments of El Paso and Juarez, photochemical production by lightning-generated NOx from aged thunderstorm outflow, downward mixing of stratospheric air, or local production from within the thunderstorm. We find that a large fraction of the ozone enhancement is consistent with local production from corona discharges, either from cloud particles or by corona associated with lightning. The implied global source of ozone from thunderstorm corona discharge is estimated to be 110 Tg O3 a-1 with a range between 40 and 180 Tg O3 a-1. This value is about 21% as large as the estimated ozone production rate from lightning NOx, and about 3% as large as the total chemical production rate of tropospheric ozone. Thus while the estimated corona-induced production of ozone may be significant on local scales, it is unlikely to be as important to the global ozone budget as other sources.

  17. Monitoring of atmospheric ozone and nitrogen dioxide over the south of Portugal by ground-based and satellite observations.

    Bortoli, Daniele; Silva, Ana Maria; Costa, Maria João; Domingues, Ana Filipa; Giovanelli, Giorgio


    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed as a result of the collaboration between CGE-UE, ISAC-CNR and Italian National Agency for New Technologies, Energy and the Environment (ENEA). SPATRAM is a multi-purpose UV-Vis-scanning spectrometer (250 - 950 nm) and it is installed at the Observatory of the CGE, in Evora, since April 2004. A brief description of the instrument is given, highlighting the technological innovations with respect to the previous version of similar equipment. The need for such measurements automatically taken on a routine basis in south-western European regions, specifically in Portugal, has encouraged the development and installation of the equipment and constitutes a major driving force for the present work. The main features and some improvements introduced in the DOAS (Differential Optical Absorption Spectroscopy) algorithms are discussed. The results obtained applying DOAS methodology to the SPATRAM spectrometer measurements of diffused spectral sky radiation are presented in terms of diurnal and seasonal variations of nitrogen dioxide (NO(2)) and ozone (O(3)). NO(2) confirms the typical seasonal cycle reaching the maximum of (6.5 +/- 0.3) x 10(+15) molecules cm(-2) for the sunset values (PM), during the summer season, and the minimum of (1.55 +/- 0.07) x 10(+15) molecules cm(-2) for the sunrise values (AM) in winter. O(3) presents the maximum total column of (433 +/- 5) Dobson Unit (DU) in the spring season and the minimum of (284 +/- 3) DU during the fall period. The huge daily variations of the O(3) total column during the spring season are analyzed and discussed. The ground-based results obtained for NO(2) and O(3) column contents are compared with data from satellite-borne equipment (GOME - Global Ozone Monitoring Experiment; SCIAMACHY - Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY; TOMS - Total Ozone Monitoring Spectrometer) and it is shown that the two data

  18. Control of disinfection by-product formation using ozone-based advanced oxidation processes.

    Chen, Kuan-Chung; Wang, Yu-Hsiang


    The effects of ozone dosage, water temperature and catalyst addition in an ozonation-fluidized bed reactor (O3/FBR) on treated water quality and on the control of chlorinated and ozonated disinfection by-products (DBPs) were investigated. A biofiltration column was used to evaluate its removal efficiency on biodegradable organic matter and to reduce DBP formation. The Dong-Gang River, polluted by agricultural and domestic wastewater in Pingtung, Taiwan, was used as the water source. The treated water quality in terms of dissolved organic carbon (DOC), biodegradable DOC, ultraviolet absorbance at 254 nm (UV254) and specific UV absorbance (SUVA) improved with increasing ozone and catalyst dosages. Catalytic ozonation was more effective than ozonation alone at reducing the formation of DBPs at a given dosage. Experimental results show that water temperature had little effect on the treated water quality with the O3/FBR system used in this study (p > 0.05). The combination of O3/FBR and the biofiltration process effectively decreased the amount ofDBP precursors. The concentration of total trihalomethanes (TTHMs) was less than the maximum contaminant level (MCL) requirement, which is 80 microg/L, for all treated waters and the concentration of five haloacetic acids (HAA5) fell below 60 microg/L with an ozone dosage higher than 2.5 mg/L.

  19. Ozonation strategies to reduce sludge production of a seafood industry WWTP.

    Campos, J L; Otero, L; Franco, A; Mosquera-Corral, A; Roca, E


    In this work, several alternatives related to the application of ozone in different streams of a seafood industry WWTP were evaluated to minimize the production of waste sludge. The WWTP was composed of two coagulation-flocculation units and a biological unit and generated around of 6550 kg/d of sludge. Ozone was applied to sludge coming from flotation units (110 g TSS/L) at doses up to 0.03 g O(3)/g TSS during batch tests, no solids solubilization being observed. Ozone doses ranging from 0.007 to 0.02 g O(3)/g TSS were also applied to the raw wastewater in a bubble column reaching a 6.8% of TSS removal for the highest ozone dose. Finally, the effect of the pre-ozonation (0.05 g O(3)/g TSS) of wastewater coming from the first flotation unit was tested in two activated sludge systems during 70 days. Ozonation caused a reduction of the observed yield coefficient of biomass from 0.14 to 0.07g TSS/g COD(Tremoved) and a slight improvement of COD removal efficiencies. On the basis of the capacity for ozone production available in the industry, a maximum reduction of sludge generated by the WWTP of 7.5% could be expected.

  20. Soil respiration, root biomass, and root turnover following long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3

    Kurt S. Pregitzer; Andrew J. Burton; John S. King; Donald R. Zak


    The Rhinelander free-air CO2 enrichment (FACE) experiment is designed to understand ecosystem response to elevated atmospheric carbon dioxide (+CO2) and elevated tropospheric ozone (+O3). The objectives of this study were: to understand how soil respiration responded to the experimental treatments; to...

  1. High-temperature vaporization of B2O3(l) under reducing conditions.

    Jacobson, Nathan S; Myers, Dwight L


    The vaporization of B(2)O(3) in a reducing environment leads to the formation of both B(2)O(3)(g) and B(2)O(2)(g). Whereas the formation of B(2)O(3)(g) is well understood, many questions about the formation of B(2)O(2)(g) remain. Previous studies using B(s) + B(2)O(3)(l) have led to inconsistent thermodynamic data. In this study, it was found that, after heating, B(s) and B(2)O(3)(l) appeared to separate and variations in contact area likely led to the inconsistent vapor pressures of B(2)O(2)(g). To circumvent this problem, the activity of boron was fixed with a two-phase mixture of FeB and Fe(2)B. Both second- and third-law enthalpies of formation were measured for B(2)O(2)(g) and B(2)O(3)(g). From these values, the enthalpies of formation at 298.15 K were calculated to be -479.9 ± 25.7 kJ/mol for B(2)O(2)(g) and -833.4 ± 13.1 kJ/mol for B(2)O(3)(g). Ab initio calculations to determine the enthalpies of formation of B(2)O(2)(g) and B(2)O(3)(g) were conducted using the W1BD composite method and showed good agreement with the experimental values.

  2. Photoluminescence of monolayer MoS2 on LaAlO3 and SrTiO3 substrates.

    Li, Yuanyuan; Qi, Zeming; Liu, Miao; Wang, Yuyin; Cheng, Xuerui; Zhang, Guobin; Sheng, Liusi


    In an atomically thin-film/dielectric-substrate heterostructure, the elemental physical properties of the atomically thin-film are influenced by the interaction between the thin-film and the substrate. In this article, utilizing monolayer MoS(2) on LaAlO(3) and SrTiO(3) substrates, as well as SiO2 and Gel-film as reference substrates similar to previously reported work [Nano Res, 2014, 7, 561], we systematically investigate the substrate effect on the photoluminescence of monolayer MoS(2). We observed significantly substrate-dependant photoluminescence of monolayer MoS(2), originating from substrate-to-film charge transfer. We found that SiO2 substrate introduces the most charge doping while SrTiO(3) introduces less charge transfer. Through the selection of desired substrate, we are able to induce different amounts of charge into the monolayer MoS(2), which consequently modifies the neutral exciton and charged exciton (trion) emissions. Finally, we proposed a band-diagram model to elucidate the relation between charge transfer and the substrate Fermi level and work function. Our work demonstrates that the substrate charge transfer exerts a strong influence on the monolayer MoS(2) photoluminescence property, which should be considered during device design and application. The work also provides a possible route to modify the thin-film photoluminescence property via substrate engineering for future device design.

  3. A kinetic model of Ti(Ⅳ)-catalyzed H2O2/O3 process in aqueous solution

    Shaoping Tong; Shuqin Zhao; Xiaofei Lan; Chunan Ma


    To well describe the Ti(Ⅳ)-catalyzed H2O2/O3 reaction in aqueous solution,a kinetic model was established based on its mechanism.This model was then validated by the experiments of acetic acid degradation in aqueous solution.It was found that the correlation coefficient of fittings was higher than 0.970.Three key operating factors affecting organic degradation in the Ti(Ⅳ)-catalyzed H2O2/O3 process were studied,including Ti(Ⅳ) concentration,dissolved ozone concentration and initial H2O2 concentration.Furthermore,some experiments were conducted to determine the rate constant for dissolved ozone decomposition initiated by Ti2O52+.The rate constant measured is almost in accord with the data analyzed by this kinetic model.The goodness of fittings demonstrated that this model could well describe the kinetics of the Ti(Ⅳ)-catalyzed H2O2/O3 reaction mathematically and chemically.Therefore,this kinetic model can provide some useful information to optimize the parameters in ozonation of water containing certain pollutants.

  4. OH and O3 in the MLT: Comparing MAHRSI and ORA measurements With the SOCRATES 2D-model

    Chabrillat, S.; Kockarts, G.; Brasseur, G.; Fussen, D.; Fonteyn, D.


    New space-based measurements of two key chemical species in the MLT, OH and O3\\ , were recently published. The OH radical was measured for the first time in the stratosphere and the mesosphere by the MAHRSI instrument. Conway et al. [2000] showed the difficulty to explain these observations with a one-dimensional model. Ozone measurements were extracted from the ORA instrument, which uses solar occultation in the UV-visible wavelength range. More than 2500 vertical profiles of O3 at sunrise and sunset were obtained, up to 110 km altitude. This is the first ozone data set to extend above the mesopause, capturing the ozone secondary maximum in its totality. We compare these measurements with the results of the SOCRATES two-dimensional interactive model. The latest version of this model includes, among other improvements, an accurate calculation of the absorption of the Lyman-α solar line by O2\\ , molecular diffusion, and a parameterization of the gravity wave drag to accurately match the observed temperature distribution in the MLT - especially the temporal and spatial structure of the mesopause. We show that the observations of mesospheric OH and O3 in the MLT are reproduced in a very satisfactory manner using this new multi-dimensional model.

  5. Reactive uptake of ozone at simulated leaf surfaces: Implications for 'non-stomatal' ozone flux

    Cape, J. Neil; Hamilton, Richard; Heal, Mathew R.

    The reaction of ozone (O 3) with α-pinene has been studied as a function of temperature and relative humidity and in the presence of wax surfaces that simulate a leaf surface. The objective was to determine whether the presence of a wax surface, in which α-pinene could dissolve and form a high surface concentration, would lead to enhanced reaction with O 3. The reaction of O 3 itself with the empty stainless steel reactor and with aluminium and wax surfaces demonstrated an apparent activation energy of around 30 kJ mol -1 for all the surfaces, similar to that observed in long-term field measurements of O 3 fluxes to vegetation. However, the absolute reaction rate was 14 times greater for aluminium foil and saturated hydrocarbon wax surfaces than for stainless steel, and a further 5 times greater for beeswax than hydrocarbon wax. There was no systematic dependence on either relative or absolute humidity for these surface reactions over the range studied (20-100% RH). Reaction of O 3 with α-pinene occurred at rates close to those predicted for the homogeneous gas-phase reaction, and was similar for both the empty reactor and in the presence of wax surfaces. The hypothesis of enhanced reaction at leaf surfaces caused by enhanced surface concentrations of α-pinene was therefore rejected. Comparison of surface decomposition reactions on different surfaces as reported in the literature with the results obtained here demonstrates that the loss of ozone at the earth's surface by decomposition to molecular oxygen (i.e. without oxidative reaction with a substrate) can account for measured 'non-stomatal' deposition velocities of a few mm s -1. In order to quantify such removal, the effective molecular surface area of the vegetation/soil canopy must be known. Such knowledge, combined with the observed temperature-dependence, provides necessary input to global-scale models of O 3 removal from the troposphere at the earth's surface.

  6. Research on Glass Forming Ability of Er2O3 -Al2O3 -B2O3 -SiO2 System

    Zhang Qitu; Fu Zhenxiao; Ni Yaru; Lu Chunhua; Xu Zhongzi


    The glass forming range of Er2O3-Al2O3-B2O3-SiO2 system was explored, and the effect of the content of Al2 O3 and Er2 O3 on glass-forming region was experimentally examined. It is shown that the region of glass formation range expends when the content of Al2O3 is changed from 15% to 20%, while it shrinks when the content of Er2O3 is changed from 20% to 30%. At the same time, the glass forming ability of Er2O3-Al2O3-B2O3-SiO2 system was also discussed using a value of β, which is an indication of crystallization tendency of glasses, calculated from thermo-analysis data. It is found that the glass forming ability of Er2O3-Al2O3-B2O3- SiO2 glasses is poor, while the glasses network may be enhanced when Al2O3 is added to the system, the glass forming ability being heightened. In addition, the crystallization temperatures of the rare earth glasses were determined using differential thermal analysis technique. The Er2O3-Al2O;-B2O3-SiO2 glass samples were heat treated at 1000,1100 and 1260℃ respectively. The results show that it is the Er2O3 phase that separates out from the glasses after crystaline heat treatment, and it is tiered up in glasses, as detected through XRD and SEM. This indicates that the phase separation occurs when the glasses are heated, Er3+ being mainly distributed in the boron rich phase, then separated out from glasses, while the silicate rich phase remaining glassy state.

  7. Transport properties of a quasi-two-dimensional electron system formed in LaAlO3/EuTiO3/SrTiO3 heterostructures

    De Luca, G. M.; Di Capua, R.; Di Gennaro, E.; Granozio, F. Miletto; Stornaiuolo, D.; Salluzzo, M.; Gadaleta, A.; Pallecchi, I.; Marrè, D.; Piamonteze, C.; Radovic, M.; Ristic, Z.; Rusponi, S.


    We study the structural, magnetic, and transport properties of LaAlO3/EuTiO3/SrTiO3 heterostructures grown by pulsed laser deposition. The samples are characterized in situ by electron diffraction and scanning probe microscopy and ex situ by transport measurements and x-ray absorption spectroscopy. LaAlO3/EuTiO3/SrTiO3 films show a ferromagnetic transition at T ≤7.5 K, related to the ordering of Eu2+ spins, even in samples characterized by just two EuTiO3 unit cells. A finite metallic conductivity is observed only in the case of samples composed by one or two EuTiO3 unit cells and, simultaneously, by a LaAlO3 thickness greater than or equal to four unit cells. The effect of ferromagnetic EuTiO3 on the transport properties of δ-doped LaAlO3/EuTiO3/SrTiO3 is critically discussed.

  8. Significant increase of summertime ozone at Mount Tai in Central Eastern China

    Sun, Lei; Xue, Likun; Wang, Tao; Gao, Jian; Ding, Aijun; Cooper, Owen R.; Lin, Meiyun; Xu, Pengju; Wang, Zhe; Wang, Xinfeng; Wen, Liang; Zhu, Yanhong; Chen, Tianshu; Yang, Lingxiao; Wang, Yan; Chen, Jianmin; Wang, Wenxing


    Tropospheric ozone (O3) is a trace gas playing important roles in atmospheric chemistry, air quality and climate change. In contrast to North America and Europe, long-term measurements of surface O3 are very limited in China. We compile available O3 observations at Mt. Tai - the highest mountain over the North China Plain - during 2003-2015 and analyze the decadal change of O3 and its sources. A linear regression analysis shows that summertime O3 measured at Mt. Tai has increased significantly by 1.7 ppbv yr-1 for June and 2.1 ppbv yr-1 for the July-August average. The observed increase is supported by a global chemistry-climate model hindcast (GFDL-AM3) with O3 precursor emissions varying from year to year over 1980-2014. Analysis of satellite data indicates that the O3 increase was mainly due to the increased emissions of O3 precursors, in particular volatile organic compounds (VOCs). An important finding is that the emissions of nitrogen oxides (NOx) have diminished since 2011, but the increase of VOCs appears to have enhanced the ozone production efficiency and contributed to the observed O3 increase in central eastern China. We present evidence that controlling NOx alone, in the absence of VOC controls, is not sufficient to reduce regional O3 levels in North China in a short period.

  9. O(3)-invariant tunneling in general relativity

    Berezin, V.A.; Tkachev, I.I.; Kuzmin, V.A.


    We derived a general formula for the action for any O(3)-invariant tunneling processes in false vacuum decay in general relativity. The general classification of the bubble euclidean trajectories is elaborated and explicit expressions for bounces for some processes like the vacuum creation of a double bubble in particular in the vicinity of a black hole, the subbarrier creation of the Einstein-Rosen bridge, creation from nothing of two Minkowski worlds connected by a shell, etc., are given.

  10. Overview of the O3M SAF GOME-2 operational atmospheric composition and UV radiation data products and data availability

    S. Hassinen


    Full Text Available The three GOME-2 instruments will provide unique and long data sets for atmospheric research and applications. The complete time period will be 2007–2022, including the period of ozone depletion as well as the beginning of ozone layer recovery. Besides ozone chemistry, the GOME-2 products are important e.g. for air quality studies, climate modeling, policy monitoring and hazard warnings. The heritage for GOME-2 is in the ERS/GOME and Envisat/SCIAMACHY instruments. The current Level 2 (L2 data cover a wide range of products such as trace gas columns (NO2, BrO, H2CO, H2O, SO2, tropospheric columns of NO2, total ozone columns and vertical ozone profiles in high and low spatial resolution, absorbing aerosol indices from the main science channels as well as from the polarization channels (AAI, AAI-PMD, Lambertian-equivalent reflectivity database, clear-sky and cloud-corrected UV indices and surface UV fields with different weightings and photolysis rates. The Ozone Monitoring and Atmospheric Composition Satellite Application Facility (O3M SAF processing and data dissemination is operational and running 24/7. Data quality is quarantined by the detailed review processes for the algorithms, validation of the products as well as by a continuous quality monitoring of the products and processing. This is an overview paper providing the O3M SAF project background, current status and future plans to utilization of the GOME-2 data. An important focus is the provision of summaries of the GOME-2 products including product principles and validation examples together with the product sample images. Furthermore, this paper collects the references to the detailed product algorithm and validation papers.

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

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


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

  12. Ozone measurements in Amazonia - Dry season versus wet season

    Kirchhoff, V. W. J. H.; Da Silva, I. M. O.; Browell, Edward V.


    Recent ozone measurements taken in the Amazonian rain forest environment during the wet season (April-May 1987) are described, revealling new aspects of the regional atmospheric chemistry. The measurements were part of the Amazon Boundary Layer Experiment (ABLE 2B) mission and utilized UV absorption as a measurement technique to obtain surface ozone data; 20 ozonesondes were launched in order to obtain vertical ozone profiles used to describe the upper troposphere and stratosphere. The major differences in comparison to a previous dry season experiment, which found ozone concentrations to be lower in the whole troposphere by nearly a factor of 2, are stressed.

  13. Schottky contacts to In2O3

    H. von Wenckstern


    Full Text Available n-type binary compound semiconductors such as InN, InAs, or In2O3 are especial because the branch-point energy or charge neutrality level lies within the conduction band. Their tendency to form a surface electron accumulation layer prevents the formation of rectifying Schottky contacts. Utilizing a reactive sputtering process in an oxygen-containing atmosphere, we demonstrate Schottky barrier diodes on indium oxide thin films with rectifying properties being sufficient for space charge layer spectroscopy. Conventional non-reactive sputtering resulted in ohmic contacts. We compare the rectification of Pt, Pd, and Au Schottky contacts on In2O3 and discuss temperature-dependent current-voltage characteristics of Pt/In2O3 in detail. The results substantiate the picture of oxygen vacancies being the source of electrons accumulating at the surface, however, the position of the charge neutrality level and/or the prediction of Schottky barrier heights from it are questioned.

  14. Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient

    Influences of ozone (O3) on light-saturated rates of photosynthesis in crop leaves have been well documented. To increase our understanding of O3 effects on individual- or stand level productivity, a mechanistic understanding of factors determining canopy photosynthesis is necessary. We used a canop...

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

    The rising trend in concentrations of ground-level ozone (O3) – a common air pollutant and phytotoxin – currently being experienced in some world regions represents a threat to agricultural yield. Soybean (Glycine max (L.) Merr.) is an O3-sensitive crop species, and is experiencing increasing globa...

  16. Characterizing the Vertical Processes of Ozone in Colorado's Front Range Using the GSFC Ozone DIAL

    Sullivan, John T.; McGee, Thomas J.; Hoff, Raymond M.; Sumnicht, Grant; Twigg, Laurence


    Although characterizing the interactions of ozone throughout the entire troposphere are important for health and climate processes, there is a lack of routine measurements of vertical profiles within the United States. In order to monitor this lower ozone more effectively, the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) has been developed and validated within the Tropospheric Ozone Lidar Network (TOLNet). Two scientifically interesting ozone episodes are presented that were observed during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER AQ) campaign at Ft. Collins, Colorado. The first case study, occurring between 22-23 July 2014, indicates enhanced concentrations of ozone at Ft. Collins during nighttime hours, which was due to the complex recirculation of ozone within the foothills of the Rocky Mountain region. Although quantifying the ozone increase aloft during recirculation episodes has been historically difficult, results indicate that an increase of 20 - 30 ppbv of ozone at the Ft. Collins site has been attributed to this recirculation. The second case, occurring between Aug 4-8th 2014, characterizes a dynamical exchange of ozone between the stratosphere and the troposphere. This case, along with seasonal model parameters from previous years, is used to estimate the stratospheric contribution to the Rocky Mountain region. Results suggest that a large amount of stratospheric air is residing in the troposphere in the summertime near Ft. Collins, CO. The results also indicate that warmer tropopauses are correlated with an increase in stratospheric air below the tropopause in the Rocky Mountain Region.

  17. Stratospheric ozone depletion due to nitrous oxide: influences of other gases.

    Portmann, R W; Daniel, J S; Ravishankara, A R


    The effects of anthropogenic emissions of nitrous oxide (N(2)O), carbon dioxide (CO(2)), methane (CH(4)) and the halocarbons on stratospheric ozone (O(3)) over the twentieth and twenty-first centuries are isolated using a chemical model of the stratosphere. The future evolution of ozone will depend on each of these gases, with N(2)O and CO(2) probably playing the dominant roles as halocarbons return towards pre-industrial levels. There are nonlinear interactions between these gases that preclude unambiguously separating their effect on ozone. For example, the CH(4) increase during the twentieth century reduced the ozone losses owing to halocarbon increases, and the N(2)O chemical destruction of O(3) is buffered by CO(2) thermal effects in the middle stratosphere (by approx. 20% for the IPCC A1B/WMO A1 scenario over the time period 1900-2100). Nonetheless, N(2)O is expected to continue to be the largest anthropogenic emission of an O(3)-destroying compound in the foreseeable future. Reductions in anthropogenic N(2)O emissions provide a larger opportunity for reduction in future O(3) depletion than any of the remaining uncontrolled halocarbon emissions. It is also shown that 1980 levels of O(3) were affected by halocarbons, N(2)O, CO(2) and CH(4), and thus may not be a good choice of a benchmark of O(3) recovery.

  18. Upper limit to magnetism in LaAlO3/SrTiO3 heterostructures

    Fitzsimmons, Michael


    In 2004 Ohtomo and Hwang reported unusually high conductivity in LaAlO3 and SrTiO3 bilayer samples. Since then, metallic conduction, superconductivity, magnetism, and coexistence of superconductivity and ferromagnetism have been attributed to LaAlO3/SrTiO3 interfaces. Very recently, two studies have reported large magnetic moments attributed to interfaces from measurement techniques that are unable to distinguish between interfacial and bulk magnetism. Consequently, it is imperative to perform magnetic measurements that by being intrinsically sensitive to interface magnetism are impervious to experimental artifacts suffered by bulk measurements. Using polarized neutron reflectometry, we measured the neutron spin dependent reflectivity from four LaAlO3/SrTiO3 superlattices. Our results indicate the upper limit for the magnetization averaged over the lateral dimensions of the sample induced by an 11 T magnetic field at 1.7 K is less than 2 G. SQUID magnetometry of the neutron superlattice samples sporadically finds an enhanced moment (consistent with past reports), possibly due to experimental artifacts. These observations set important restrictions on theories which imply a strongly enhanced magnetism at the interface between LaAlO3 and SrTiO3. Work performed in collaboration with N.W. Hengartner, S. Singh, M. Zhernenkov (LANL), F.Y. Bruno, J. Santamaria (Universidad Complutense de Madrid), A. Brinkman, M.J.A. Huijben, H. Molegraaf (MESA+ Institute for Nanotechnology), J. de la Venta and Ivan K. Schuller (UCSD). [4pt] Work supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS and DMR under grant DE FG03-87ER-45332. Work at UCM is supported by Consolider Ingenio CSD2009-00013 (IMAGINE), CAM S2009-MAT 1756 (PHAMA) and work at Twente is supported by the Foundation for Fundamental Research on Matter (FOM).

  19. Regional ozone pollution and key controlling factors of photochemical ozone production in Pearl River Delta during summer time

    CHANG; ChihChung; CHOU; C.K.Charles; Andreas; Wahner


    An intensive field campaign including measurements from the environmental monitoring network and from two super sites took place in the Pearl River Delta region in summer 2006.Using routinely measured O3 and NOx concentrations,the spatial and temporal variation of O3 and of the total oxidant concentrations was characterized.According to the spatial variability of NO2/NO,the two super sites were found to be representative of polluted urban and downwind suburban conditions.In addition,both sites were located in high O3 regions.In-depth diagnostic of photochemical ozone production processes and their key controlling factors are achieved with an observation-based model(OBM) to gain regional perspectives.Budget analysis and sensitivity model runs show that aldehyde and HONO chemistry had significant impacts on local photochemical ozone production rates.The analysis of calculated Relative Incremental Reactivities shows that photochemical ozone production rates are mainly sensitive to anthropogenic hydrocarbons(HCs) in the polluted urban areas.In the suburban areas,sensitivity to nitrogen oxide(NO) concentrations dominated.Key anthropogenic HCs in both areas are alkenes and aromatics.Significant differences of ozone production efficiencies are identified between the urban and suburban regions,consistent with the OBM diagnosed results.

  20. Surface Spectroscopy Studies of the Reactive Uptake of Ozone on Alkali Halides

    Newberg, J. T.; Hemminger, J. C.


    the O(1s) photoelectron peak. Initial XPS spectra of salts in the vacuum chamber prior to ozone exposure indicated that the salts were either devoid of oxygen, or contained a small amount of oxygen from strongly adsorbed water under ultra-high vacuum. In all cases, in-vacuo exposure of the salts to ozone lead to an increase in O(1s) photoelectron signal. For NaCl this was surprising since previous studies have been interpreted to indicate that ozone is essentially unreactive towards solid NaCl. The initial uptake of oxygen on the surface gave a broad O(1s) peak, indicating that there are several types of oxygen species on the surface. Reference spectra were obtained for NaClO2, NaClO3, and NaClO4 salts. The O(1s) binding energies in these reference spectra increased in series with NaClO2 doses. The oxygen uptake upon ozone exposure to alkali bromide and iodide salts were also investigated and compared to reference salts. Future work will incorporate the influence of adsorbed water and subsequent ozone exposures on the surface chemistry of salts.

  1. Simplified Modeling of Tropospheric Ozone Formation Considering Alternative Fuels Using

    Leonardo Aragão Ferreira da Silva


    Full Text Available Brazilian cities have been constantly exposed to air quality episodes of high ozone concentrations (O3 . Known for not be emitted directly into the environment, O3 is a result of several chemical reactions of other pollutants emitted to atmosphere. The growth of vehicle fleet and government incentives for using alternative fuels like ethanol and Compressed Natural Gas (CNG are changing the Brazilian Metropolitan Areas in terms of acetaldehyde and formaldehyde emissions, Volatile Organic Compounds (VOC's present in the atmosphere and known to act on the kinetics of ozone. Driven by high concentrations of tropospheric ozone in urban/industry centers and its implications for environment and population health, the target of this work is understand the kinetics of ozone formation through the creation of a mathematical model in FORTRAN 90, describing a system of coupled ordinary differential equations able to represent a simplified mechanism of photochemical reactions in the Brazilian Metropolitan Area. Evaluating the concentration results of each pollutant were possible to observe the precursor’s influence on tropospheric ozone formation, which seasons were more conducive to this one and which are the influences of weather conditions on formation of photochemical smog.

  2. Plant resistance mechanisms to air pollutants: rhythms in ascorbic acid production during growth under ozone stress

    Lee, E.H. (Climate Stress Laboratory, USDA, ARS, Beltsville, MD (United States))


    Relationships between ozone (O3) tolerance and leaf ascorbic acid concentrations in O3-susceptible (O3-S) 'Hark' and O3-resistant (O3-R) 'Hood' soybean, Glycine max (L.) Merr., cultivars were examined with high-performance liquid chromatography (HPLC). Leaf samples were analyzed at 4 intervals during a 24 h period. Soybean cultivars grown in the greenhouse with charcoal filtered (CF) and nonfiltered (NF) air showed daily oscillations in ascorbic acid production. Highest ascorbic acid levels in leaves during light coincided with highest concentrations of photochemical oxidants in the atmosphere at 2:00 p.m. The resistant genotype produced more ascorbic acid in its trifoliate leaves than did the corresponding susceptible genotype. Under CF air (an O3-reduced environment) O3-S and O3-R cultivars showed rhythms in ascorbic acid production. In NF air (an O3 stress environment) the O3-R cultivar alone showed rhythms in ascorbic acid production. Results indicated that superior O3 tolerance in the Hood soybean cultivar (compared with Hark) was associated with a greater increase in endogenous levels of ascorbic acid. Ascorbic acid may scavenge free radicals and thereby protect cells from injury by O3 or other oxyradical products. Plants defend themselves against photochemical oxidant stress, such as O3, by several mechanisms. Experimental evidence indicates that antioxidant defense systems existing in plant tissues may function to protect cellular components from deleterious effects of photochemical oxidants through endogenous and exogenous controls.

  3. Nature of weak magnetism in SrTiO3/LaAlO3 multilayers.

    Salman, Z; Ofer, O; Radovic, M; Hao, H; Ben Shalom, M; Chow, K H; Dagan, Y; Hossain, M D; Levy, C D P; Macfarlane, W A; Morris, G M; Patthey, L; Pearson, M R; Saadaoui, H; Schmitt, T; Wang, D; Kiefl, R F


    We report the observation of weak magnetism in superlattices of LaAlO(3)/SrTiO(3) using β-detected nuclear magnetic resonance. The spin lattice relaxation rate of ^{8}Li in superlattices with a spacer layers of 8 and 6 unit cells of LaAlO(3) exhibits a strong peak near ~35 K, whereas no such peak is observed in a superlattice with spacer layer thickness of 3 unit cells. We attribute the observed temperature dependence to slowing down of weakly coupled electronic moments at the LaAlO(3)/SrTiO(3) interface. These results show that the magnetism at the interface depends strongly on the thickness of the spacer layer, and that a minimal thickness of ~4-6 unit cells is required for the appearance of magnetism. A simple model is used to determine that the observed relaxation is due to small fluctuating moments (~0.002μ(B)) in the two samples with a larger LaAlO(3) spacer thickness.

  4. Interfacial-layers-free Ga2O3(Gd2O3)/Ge MOS Diodes

    Lee, C. H.; Lin, T. D.; Lee, K. Y.; Huang, M. L.; Tung, L. T.; Hong, M.; Kwo, J.


    High κ dielectric Ga2O3(Gd2O3) films were deposited directly on Ge by Molecular-Beam-Epitaxy without the employment of GeON interfacial layer. Excellent electrical properties, such as a high κ value of 14.5, a low leakage current density of only 3x10-9 A/cm^2 at Vfb+1V, and well-behaved CV characteristics, were demonstrated, even being subjected to a 500^oC annealing in N2 ambient for 5 min. An abrupt Ga2O3(Gd2O3)/Ge interface without any interfacial layer was revealed by high-resolution transmission electron microscopy as well as in-situ x-ray photoelectron spectroscopy (XPS). Detailed XPS studies indicate that the oxide/Ge interface consists of mainly Ge-O-Gd bonding, distinctly different from that of native oxide. Furthermore, the 500^oC annealing did not change the chemical bonding, implying a great thermodynamic stability of the hetero-structure. The outstanding electrical and thermodynamic properties qualified Ga2O3(Gd2O3) as a promising dielectric for Ge and proved the GeON interfacial layer to be unnecessary.

  5. Upper-tropospheric CO and O3 budget during the Asian summer monsoon

    Barret, Brice; Sauvage, Bastien; Bennouna, Yasmine; Le Flochmoen, Eric


    During the Asian summer monsoon, the circulation in the upper troposphere/lower stratosphere (UTLS) is dominated by the Asian monsoon anticyclone (AMA). Pollutants convectively uplifted to the upper troposphere are trapped within this anticyclonic circulation that extends from the Pacific Ocean to the Eastern Mediterranean basin. Among the uplifted pollutants are ozone (O3) and its precursors, such as carbon monoxide (CO) and nitrogen oxides (NOx). Many studies based on global modeling and satellite data have documented the source regions and transport pathways of primary pollutants (CO, HCN) into the AMA. Here, we aim to quantify the O3 budget by taking into consideration anthropogenic and natural sources. We first use CO and O3 data from the MetOp-A/IASI sensor to document their tropospheric distributions over Asia, taking advantage of the useful information they provide on the vertical dimension. These satellite data are used together with MOZAIC tropospheric profiles recorded in India to validate the distributions simulated by the global GEOS-Chem chemistry transport model. Over the Asian region, UTLS monthly CO and O3 distributions from IASI and GEOS-Chem display the same large-scale features. UTLS CO columns from GEOS-Chem are in agreement with IASI, with a low bias of 11 ± 9 % and a correlation coefficient of 0.70. For O3, the model underestimates IASI UTLS columns over Asia by 14 ± 26 % but the correlation between both is high (0.94). GEOS-Chem is further used to quantify the CO and O3 budget through sensitivity simulations. For CO, these simulations confirm that South Asian anthropogenic emissions have a more important impact on enhanced concentrations within the AMA (˜ 25 ppbv) than East Asian emissions (˜ 10 ppbv). The correlation between enhanced emissions over the Indo-Gangetic Plain and monsoon deep convection is responsible for this larger impact. Consistently, South Asian anthropogenic NOx emissions also play a larger role in producing O3 within

  6. Ozone therapy in periodontics.

    Gupta, G; Mansi, B


    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics.

  7. Use of pulse radiolysis for the study of the chemistry of aqueous ozone and ozonide solutions

    Sehested, Knud; Holcman, Jerzy; Bjergbakke, Erling


    The chemistry of aqeous ozone, O3, and ozonide, O3−, is of great interest from a technological, environmental and scientific point of view. The literature about their aqueous chemistry is extensive, the reaction mechanisms are still not well understood. The ozonide anion is a free radical...... of a detailed mechanism. We have investigated the reaction mechanisms using pulse radiolysis in combination with a high pressure cell, rapid mixing and numerical simulation of the experiments. This study makes it possible to give a detailed description of the reaction mechanisms in terms of uni- and bimolecular...... reactions and provides kinetic data sufficient for computer simulations of aqueous O3/O3− chemistry....

  8. Vertical Distribution of Ozone and Nitric Acid Vapor on the Mammoth Mountain, Eastern Sierra Nevada, California


    In August and September 1999 and 2000, concentrations of ozone (O3) and nitric acid vapor (HNO3) were monitored at an elevation gradient (2184–3325 m) on the Mammoth Mountain, eastern Sierra Nevada, California. Passive samplers were used for monitoring exposure to tropospheric O3 and HNO3 vapor. The 2-week average O3 concentrations ranged between 45 and 72 ppb, while HNO3 concentrations ranged between 0.06 and 0.52 μg/m3. Similar ranges of O3 and HNO3 were determined for 2 years of the study....

  9. Mechanism for enhanced degradation of clofibric acid in aqueous by catalytic ozonation over MnOx/SBA-15.

    Sun, Qiangqiang; Wang, Yu; Li, Laisheng; Bing, Jishuai; Wang, Yingxin; Yan, Huihua


    Comparative experiments were conducted to investigate the catalytic ability of MnO(x)/SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O3/MnO(x)/SBA-15). Adsorption of CA and its intermediates by MnO(x)/SBA-15 was proved unimportant in O3/MnO(x)/SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO3) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnO(x)/SBA-15 facilitated the generation of hydroxyl radicals (OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnO(x) on SBA-15 were believed to be the main active component in MnO(x)/SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more OH.

  10. Isozyme markers associated with O(3) tolerance indicate shift in genetic structure of ponderosa and Jeffrey pine in Sequoia National Park, California.

    Staszak, J; Grulke, N E; Marrett, M J; Prus-Glowacki, W


    Effects of canopy ozone (O(3)) exposure and signatures of genetic structure using isozyme markers associated with O(3) tolerance were analyzed in approximately 20-, approximately 80-, and >200-yr-old ponderosa (Pinus ponderosa Dougl. ex Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Balf.) in Sequoia National Park, California. For both species, the number of alleles and genotypes per loci was higher in parental trees relative to saplings. In ponderosa pine, the heterozygosity value increased, and the fixation index indicated reduction of homozygosity with increasing tree age class. The opposite tendencies were observed for Jeffrey pine. Utilizing canopy attributes known to be responsive to O(3) exposure, ponderosa pine was more symptomatic than Jeffrey pine, and saplings were more symptomatic than old growth trees. We suggest that these trends are related to differing sensitivity of the two species to O(3) exposure, and to higher O(3) exposures and drought stress that younger trees may have experienced during germination and establishment.

  11. Canopy-level stomatal narrowing in adult Fagus sylvatica under O3 stress - means of preventing enhanced O3 uptake under high O3 exposure?

    Matyssek, R; Baumgarten, M; Hummel, U; Häberle, K-H; Kitao, M; Wieser, G


    Spatio-temporally consistent O(3) doses are demonstrated in adult Fagus sylvatica from the Kranzberg Forest free-air fumigation experiment, covering cross-canopy and whole-seasonal scopes through sap flow measurement. Given O(3)-driven closure of stomata, we hypothesized enhanced whole-tree level O(3) influx to be prevented under enhanced O(3) exposure. Although foliage transpiration rate was lowered under twice-ambient O(3) around noon by 30% along with canopy conductance, the hypothesis was falsified, as O(3) influx was raised by 25%. Nevertheless, the twice-ambient/ambient ratio of O(3) uptake was smaller by about 20% than that of O(3) exposure, suggesting stomatal limitation of uptake. The O(3) response was traceable from leaves across branches to the canopy, where peak transpiration rates resembled those of shade rather than sun branches. Rainy/overcast-day and nightly O(3) uptake is quantified and discussed. Whole-seasonal canopy-level validation of modelled with sap flow-derived O(3) flux becomes available in assessing O(3) risk for forest trees.

  12. Piezoelectric and Dielectric Properties of Multilayered BaTiO3/(Ba,Ca)TiO3/CaTiO3 Thin Films.

    Zhu, Xiao Na; Gao, Ting Ting; Xu, Xing; Liang, Wei Zheng; Lin, Yuan; Chen, Chonglin; Chen, Xiang Ming


    Highly oriented multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films were fabricated on Nb-doped (001) SrTiO3 (Nb:STO) substrates by pulsed laser deposition. The configurations of multilayered BaTiO3-(Ba,Ca)TiO3-CaTiO3 thin films are designed with the thickness ratio of 1:1:1 and 2:1:1 and total thickness ∼300 nm. Microstructural characterization by X-ray diffraction indicates that the as-deposited thin films are highly c-axis oriented and large in-plane strain is determined in BaTiO3 and CaTiO3 layers. Piezoresponse force microscopy (PFM) studies reveal an intense in-plane polarization component, whereas the out-of-plane shows inferior phase contrast. The optimized combination is found to be the BaTiO3-(Ba0.85Ca0.15)TiO3-CaTiO3 structure with combination ratio 2:1:1, which displays the largest domain switching amplitude under DC electric field, the largest room-temperature dielectric constant ∼646, a small dielectric loss of 0.03, and the largest dielectric tunability of ∼50% at 400 kV/cm. These results suggest that the enhanced dielectric and tunability performance are greatly associated with the large in-plane polarization component and domain switching.

  13. Formaldehyde vapor produced from hexamethylenetetramine and pesticide: Simultaneous monitoring of formaldehyde and ozone in chamber experiments by flow-based hybrid micro-gas analyzer.

    Yanaga, Akira; Hozumi, Naruto; Ohira, Shin-Ichi; Hasegawa, Asako; Toda, Kei


    Simultaneous analysis of HCHO and O3 was performed by the developed flow analysis system to prove that HCHO vapor is produced from solid pesticide in the presence of O3. HCHO is produced in many ways, including as primary emissions from fuel combustion and in secondary production from anthropogenic and biogenic volatile organic compounds by photochemical reactions. In this work, HCHO production from pesticides was investigated for the first time. Commonly pesticide contains surfactant such as hexamethylenetetramine (HMT), which is a heterocyclic compound formed from six molecules of HCHO and four molecules of NH3. HMT can react with gaseous oxidants such as ozone (O3) to produce HCHO. In the present study, a flow analysis system was developed for simultaneous analysis of HCHO and O3, and this system was used to determine if solid pesticides produced HCHO vapor in the presence of O3. HMT or the pesticide jimandaisen, which contains mancozeb as the active ingradient and HMT as a stabilizer was placed at the bottom of a 20-L stainless steel chamber. Air in the chamber was monitored using the developed flow system. Analyte gases were collected into an absorbing solution by a honeycomb-patterned microchannel scrubber that was previously developed for a micro gas analysis system (μGAS). Subsequently, indigotrisulfonate, a blue dye, was added to the absorbing solution to detect O3, which discolored the solution. HCHO was detected after mixing with the Hantzsch reaction reagent. Both gases could be detected at concentrations ranging from parts per billion by volume (ppbv) to 1000 ppbv with good linearity. Both HMT and jimandaisen emitted large amount of HCHO in the presence of O3.

  14. Enhancement Factors in Ozone Absorption Based on the Surface Renewal Model and its Application

    程江; 杨卓如; 陈焕钦; C.H.Kuo; M.E.Zappi


    Based on the Danckwerts surface renewal model, a simple explicit expression of the enhancement factor in ozone absorption with a first order ozone self-decomposition and parallel second order ozonation reactions has been derived. The results are compared with our previous work based on the film theory. The 2,4-dichlorophenol destruction rate by ozonation is predicted using the enhancement factor model in this paper.

  15. Conductivity of A- and B-site doped LaAlO3, LaGaO3, LaScO3 and LaInO3 perovskites

    Lybye, D.; Poulsen, F.W.; Mogensen, Mogens Bjerg


    The conductivity of the materials LaAlO3, LaGaO3, LaScO3 and LaInO3 all doped with 10% strontium on the A-site and 10% magnesium at the B-site has been measured at different temperatures and oxygen partial pressures. The doped LaGaO3 is found to be an almost pure ionic conductor with a conductivi...

  16. Artificial ozone holes

    Dolya, S. N.


    This article considers an opportunity of disinfecting a part of the Earth surface, occupying a large area of ten thousand square kilometers. The sunlight will cause dissociation of molecular bromine into atoms; each bromine atom kills thirty thousand molecules of ozone. Each bromine plate has a mass of forty milligrams grams and destroys ozone in the area of hundred square meters. Thus, to form the ozone hole over the area of ten thousand square kilometers, it is required to have the total ma...

  17. Thermo Scientific Ozone Analyzer Instrument Handbook

    Springston, S. R. [Brookhaven National Lab. (BNL), Upton, NY (United States)


    The primary measurement output from the Thermo Scientific Ozone Analyzer is the concentration of the analyte (O3) reported at 1-s resolution in units of ppbv in ambient air. Note that because of internal pneumatic switching limitations the instrument only makes an independent measurement every 4 seconds. Thus, the same concentration number is repeated roughly 4 times at the uniform, monotonic 1-s time base used in the AOS systems. Accompanying instrument outputs include sample temperatures, flows, chamber pressure, lamp intensities and a multiplicity of housekeeping information. There is also a field for operator comments made at any time while data is being collected.

  18. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R


    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  19. Quantifying the Impact of Tropospheric Ozone on Crops Productivity at regional scale using JULES-crop

    Leung, F.


    Tropospheric ozone (O3) is the third most important anthropogenic greenhouse gas. It is causing significant crop production losses. Currently, O3 concentrations are projected to increase globally, which could have a significant impact on food security. The Joint UK Land Environment Simulator modified to include crops (JULES-crop) is used here to quantify the impacts of tropospheric O3 on crop production at the regional scale until 2100. We evaluate JULES-crop against the Soybean Free-Air-Concentration-Enrichment (SoyFACE) experiment in Illinois, USA. Experimental data from SoyFACE and various literature sources is used to calibrate the parameters for soybean and ozone damage parameters in soybean in JULES-crop. The calibrated model is then applied for a transient factorial set of JULES-crop simulations over 1960-2005. Simulated yield changes are attributed to individual environmental drivers, CO2, O3 and climate change, across regions and for different crops. A mixed scenario of RCP 2.6 and RCP 8.5 climatology and ozone are simulated to explore the implication of policy. The overall findings are that regions with high ozone concentration such as China and India suffer the most from ozone damage, soybean is more sensitive to O3 than other crops. JULES-crop predicts CO2 fertilisation would increase the productivity of vegetation. This effect, however, is masked by the negative impacts of tropospheric O3. Using data from FAO and JULES-crop estimated that ozone damage cost around 55.4 Billion USD per year on soybean. Irrigation improves the simulation of rice only, and it increases the relative ozone damage because drought can reduce the ozone from entering the plant stomata. RCP 8.5 scenario results in a high yield for all crops mainly due to the CO2 fertilisation effect. Mixed climate scenarios simulations suggest that RCP 8.5 CO2 concentration and RCP 2.6 O3 concentration result in the highest yield. Further works such as more crop FACE-O3 experiments and more Crop

  20. (Pb,Cd)-O covalency in PbTiO3-CdTiO3 with enhanced negative thermal expansion.

    Wang, Fangfang; Xie, Ying; Chen, Jun; Fu, Honggang; Xing, Xianran


    Recently experiments have found that negative thermal expansion is a common phenomenon in PbTiO3-based materials, and their negative thermal expansion is affected by various substitutions. Interestingly, Cd substitution in PbTiO3 has a unique effect in enhancing negative thermal expansion compared with any other A-site substitutions. Therefore, studying Cd substitution in PbTiO3, the role of which still remains unclear, would bring us deeper understanding on the nature of the negative thermal expansion of PbTiO3-based materials. Structure calculations, density of states, Bader analysis and the minimum electron density of Pb1-xCdxTiO3 supercells have been reported on the chemical bond through first-principles calculations here. We found that the hybridization between (Pb,Cd)-O orbitals exists in tetragonal phase. Furthermore, the hybridization between Cd-O orbitals is stronger than that between Pb-O orbitals, and Cd-O covalency promotes the average A-site hybridization. Simultaneously, the average bulk coefficient of thermal expansion is negative and inversely proportional to the Cd substitution amount. So, (Pb,Cd)-O covalency in the tetragonal Pb1-xCdxTiO3 is responsible for the nature of enhanced negative thermal expansion in accordance with our previous experimental investigations.

  1. New thermodynamic data for CoTiO3, NiTiO3 and CoCO3 based on low-temperature calorimetric measurements

    Rohrbach Arno


    Full Text Available Abstract The low-temperature heat capacities of nickel titanate (NiTiO3, cobalt titanate (CoTiO3, and cobalt carbonate (CoCO3 were measured between 2 and 300 K, and thermochemical functions were derived from the results. Our new data show previously unknown low-temperature lambda-shaped heat capacity anomalies peaking at 37 K for CoTiO3 and 26 K for NiTiO3. From our data we calculate standard molar entropies (298.15 K for NiTiO3 of 90.9 ± 0.7 J mol-1 K-1 and for CoTiO3 of 94.4 ± 0.8 J mol-1 K-1. For CoCO3, we find only a small broad heat capacity anomaly, peaking at about 31 K. From our data, we suggest a new standard entropy (298.15 K for CoCO3 of 88.9 ± 0.7 J mol-1 K-1.

  2. Exchange interactions in the perovskites Ca1-xSrxMnO3 and RMnO3 (R=La,Pr,Sm)

    Zhou, J.-S.; Goodenough, J. B.


    Measurement of the variation of the Néel temperature TN with pressure P and the compressibility κ of the orbitally ordered Mn(III)O3 array of the RMnO3 family (R=La,Pr,Sm) and of the Mn(IV)O3 array of the Ca1-xSrxMnO3 system have enabled the determination for each of a systematic increase in κ, the magnitude of the Bloch parameter αB≡d ln TN/d ln V, and TN with decreasing bending of the (180°-φ) Mn-O-Mn bond angles. The data demonstrate that the anomalously high value of -αB=5.5 reported previously for LaMnO3 is not due to orbital order and its attendant anisotropic magnetic order. A higher |αB| than 3.3 and an increasing compressibility characterize a system on the approach from the localized-electron side to a first-order transition from localized to itinerant electronic behavior. Moreover, the puzzling empirical relationship TN˜ for the π-bonding Mn(IV)O3 array is rationalized by dominance of a semicovalent exchange term over the superexchange term in the perturbation theory for the spin-spin interatomic interactions. The data also provide indirect evidence for a transition from in-phase to out-of-phase stacking along the c axis of the (001)-plane orbital ordering that has been predicted by Mizokawa, Khomskii, and Sawatzky.

  3. Fabricating superconducting interfaces between artificially grown LaAlO3 and SrTiO3 thin films

    Danfeng Li


    Full Text Available Realization of a fully metallic two-dimensional electron gas (2DEG at the interface between artificially grown LaAlO3 and SrTiO3 thin films has been an exciting challenge. Here we present for the first time the successful realization of a superconducting 2DEG at interfaces between artificially grown LaAlO3 and SrTiO3 thin films. Our results highlight the importance of two factors—the growth temperature and the SrTiO3 termination. We use local friction force microscopy and transport measurements to determine that in normal growth conditions the absence of a robust metallic state at low temperature in the artificially grown LaAlO3/SrTiO3 interface is due to the nanoscale SrO segregation occurring on the SrTiO3 film surface during the growth and the associated defects in the SrTiO3 film. By adopting an extremely high SrTiO3 growth temperature, we demonstrate a way to realize metallic, down to the lowest temperature, and superconducting 2DEG at interfaces between LaAlO3 layers and artificially grown SrTiO3 thin films. This study paves the way to the realization of functional LaAlO3/SrTiO3 superlattices and/or artificial LaAlO3/SrTiO3 interfaces on other substrates.

  4. Oxidative degradation of N-Nitrosopyrrolidine by the ozone/UV process: Kinetics and pathways.

    Chen, Zhi; Fang, Jingyun; Fan, Chihhao; Shang, Chii


    N-Nitrosopyrrolidine (NPYR) is an emerging contaminant in drinking water and wastewater. The degradation kinetics and mechanisms of NPYR degradation by the O3/UV process were investigated and compared with those of UV direct photolysis and ozonation. A synergistic effect of ozone and UV was observed in the degradation of NPYR due to the accelerated production of OH• by ozone photolysis. This effect was more pronounced at higher ozone dosages. The second-order rate constants of NPYR reacting with OH• and ozone was determined to be 1.38 (± 0.05) × 10(9) M(-1) s(-1) and 0.31 (± 0.02) M(-1) s(-1), respectively. The quantum yield by direct UV photolysis was 0.3 (± 0.01). An empirical model using Rct (the ratio of the exposure of OH• to that of ozone) was established for NPYR degradation in treated drinking water and showed that the contributions of direct UV photolysis and OH• oxidation on NPYR degradation were both significant. As the reaction proceeded, the contribution by OH• became less important due to the exhausting of ozone. Nitrate was the major product in the O3/UV process by two possible pathways. One is through the cleavage of nitroso group to form NO• followed by hydrolysis, and the other is the oxidation of the intermediates of amines by ozonation.

  5. Oxygen/ozone as a medical gas mixture. A critical evaluation of the various methods clarifies positive and negative aspects

    Bocci Velio


    Full Text Available Abstract Besides oxygen, several other gases such as NO, CO, H2, H2S, Xe and O3 have come to age over the past few years. With regards to O3, its mechanisms of action in medicine have been clarified during the last two decades so that now a comprehensive framework for understanding and recommending ozone therapy in various pathologies is available. O3 used within the determined therapeutic window is absolutely safe and more effective than golden standard medications in numerous pathologies, like vascular diseases. However, ozone therapy is mostly in practitioners' hands and some recent developments for increasing cost effectiveness and speed of treatment are neither standardized, nor evaluated toxicologically. Hence, the aim of this article is to emphasize the need to objectively assess the pros and cons of oxygen/ozone as a medical gas mixture in the hope that ozone therapy will be accepted by orthodox medicine in the near future.

  6. Novel α-Fe2O3/CdS cornlike nanorods with enhanced photocatalytic performance.

    Shi, Ye; Li, Hanying; Wang, Ling; Shen, Wei; Chen, Hongzheng


    Various semiconductors have been studied as photocatalysts for photocatalytic degradation of pollutants in aqueous solutions. As one of the promising visible-light-driven semiconductor photocatalysts, α-Fe(2)O(3) has advantages of low cost and stability. However, its application is inhibited by the poor separation of photogenerated electron-hole pair. In this work, hybrid structures were prepared to improve the performance of α-Fe(2)O(3). CdS nanoparticles were overgrown on the preformed single-crystalline α-Fe(2)O(3) nanorods by a simple and mild one-step wet-chemical method, resulting in α-Fe(2)O(3)/CdS cornlike nanocomposites. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy showed the α-Fe(2)O(3)/CdS core/shell heterostructure of the nanocomposite with high crystallinity. Furthermore, the cornlike nanocomposites exhibited superior photocatalytic performances under visible light irradiation over the pure α-Fe(2)O(3) nanorods and CdS nanoparticles. The photocatalytic activity of the composites is superior to the previously-reported pure α-Fe(2)O(3) nanomaterials, and the performance is comparable to both the commercial TiO(2) (P25) which is used under UV irradiation and the newly developed α-Fe(2)O(3)/SnO(2) photocatalyst under visible light irradiation. The enhanced performance is associated with the larger surface area of the cornlike structure, the crystalline nature of the materials and the synergy in light absorption and charge separation between α-Fe(2)O(3) and CdS. As such, our α-Fe(2)O(3)/CdS cornlike nanocomposites may be promising to be used as visible-light-driven high-performance photocatalyst.

  7. SMM mesospheric ozone measurements

    Aikin, A. C.


    The main objective was to understand the secular and seasonal behavior of ozone in the lower mesosphere, 50 to 70 km. This altitude region is important in understanding the factors which determine ozone behavior. A secondary objective is the study of stratospheric ozone in the polar regions. Use is made of results from the SBUV satellite borne instrument. In the Arctic the interaction between chlorine compounds and low molecular weight hydrocarbons is studied. More than 30,000 profiles were obtained using the UVSP instrument on the SMM spacecraft. Several orbits of ozone data per day were obtained allowing study of the current rise in solar activity from the minimum until the present. Analysis of Nimbus 7 SBUV data in Antarctic spring indicates that ozone is depleted within the polar vortex relative to ozone outside the vortex. This depletion confirms the picture of ozone loss at altitudes where polar stratospheric clouds exist. In addition, there is ozone loss above the cloud level indicating that there is another mechanism in addition to ozone loss initiated by heterogeneous chlorine reactions on cloud particles.

  8. Stomata open at night in pole-sized and mature ponderosa pine: implications for O3 exposure metrics.

    Grulke, N E; Alonso, R; Nguyen, T; Cascio, C; Dobrowolski, W


    Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) is widely distributed in the western USA. We report the lack of stomatal closure at night in early summer for ponderosa pine at two of three sites investigated. Trees at a third site with lower nitrogen dioxide and nitric acid exposure, but greater drought stress, had slightly open stomata at night in early summer but closed stomata at night for the rest of the summer. The three sites had similar background ozone exposure during the summer of measurement (2001). Nighttime stomatal conductance (gs) ranged from one tenth to one fifth that of maximum daytime values. In general, pole-sized trees ( 250 years old). In late summer, nighttime gs was low (< 3.0 mmol H2O m(-2) s(-1)) for both tree size classes at all sites. Measurable nighttime gs has also been reported in other conifers, but the values we observed were higher. In June, nighttime ozone (O3) uptake accounted for 9, 5 and 3% of the total daily O3 uptake of pole-sized trees from west to east across the San Bernardino Mountains. In late summer, O3 uptake at night was < 2% of diel uptake at all sites. Nocturnal O3 uptake may contribute to greater oxidant injury development, especially in pole-sized trees in early summer.

  9. Numerical Simulation Study on the Impacts of Tropospheric O3 and CO2 Concentration Changes on Winter Wheat.Part Ⅰ: Model Description

    ZHENG Changling; WANG Chunyi


    Ozone is well documented as the air pollutant most damaging to agricultural crops and other plants.It is reported that tropospheric O3 concentration increases rapidly in recent 20 years.Evaluating and predicting impacts of ozone concentration changes on crops are drawing great attention in the scientific community. In China, main study method about this filed is controlled experiments, for example, Open Top Chambers. But numerical simulation study about impacts of ozone on crops with crop model was developed slowly, what is more, the study about combined impacts of ozone and carbon dioxide has not been reported.The improved agroecosystem model is presented to evaluate simultaneously impacts of tropospheric O3and CO2 concentration changes on crops in the paper by integrating algorithms about impacts of ozone on photosynthesis with an existing agroecosystem biogeochemical model (named as DNDC). The main physiological processes of crop growth (phenology, leaf area index, photosynthesis, respiration, assimilated allocation and so on) in the former DNDC are kept. The algorithms about impacts of ozone on photosynthesis and winter wheat leaf are added in the modified DNDC model in order to reveal impacts of ozone and carbon dioxide on growth, development, and yield formation of winter wheat by coupling the simulation about impacts of carbon dioxide on photosynthesis of winter wheat which exists in the former DNDC. In the paper, firstly assimilate allocation algorithms and some genetic parameters (such as daily thermal time of every development stage) were modified in order that DNDC can be applicable in North China. Secondly impacts of ozone on crops were simulated with two different methods- one was impacts of ozone on light use efficiency, and the other was direct effects of ozone on leaves photosynthesis. The latter simulated results are closer to experiment measurements through comparing their simulating results. At last the method of direct impacts of ozone on leaf

  10. Seasonal variation of the O3-CO correlation derived from remote sensing measurements over western Japan

    Ohyama, Hirofumi; Kawakami, Shuji; Uchino, Osamu; Sakai, Tetsu; Morino, Isamu; Nagai, Tomohiro; Shiomi, Kei; Sakashita, Masanori; Akaho, Taiga; Okumura, Hiroshi; Arai, Kohei


    We used a lower tropospheric ozone column (LTOC) and column-averaged dry-air mole fraction of carbon monoxide (XCO) data observed in the area around Saga, which is located in western Japan and is close to the Asian continent, with an aim to investigate whether these data can characterize the seasonal variation of the photochemical ozone (O3) formation in the northeast Asian Pacific rim region. The LTOC data after April 2009 were retrieved from thermal infrared spectra measured by the Thermal and Near Infrared Sensor for Carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) onboard the Greenhouse Gases Observing Satellite (GOSAT). The XCO data after July 2011 were obtained from ground-based high-resolution FTS measurements at Saga. The retrieved LTOCs were validated with those derived from a differential absorption lidar for O3 at Saga. The LTOCs showed a distinct seasonal variation that reached a maximum in late spring (May or June) and a local minimum in winter. In addition to the general seasonal pattern, we observed pronounced minimums in July or August. The XCO concentrations showed a maximum in spring and a minimum in summer. These seasonal patterns are consistent with those observed from mountainous sites in Japan. The origins of the air masses reaching Saga were characterized for each season according to backward trajectories, and the factors causing the temporal variations of the LTOCs and the XCO were identified based on the transport paths of the air masses. The enhancement of the LTOC relative to the XCO (ΔO3/ΔCO ratio) reveals significant positive correlations in the spring and summer seasons with slopes of 0.21 and 0.45 ppb/ppb, respectively. The effects of stratospheric air intrusion on the observed ΔO3/ΔCO ratio in spring were investigated using meteorological data (backward trajectory and potential vorticity) and column-averaged hydrogen fluoride data derived from the ground-based FTS measurements. It was found that there was little

  11. O3 variability in the troposphere as observed by IASI over 2008-2016: Contribution of atmospheric chemistry and dynamics

    Wespes, C.; Hurtmans, D.; Clerbaux, C.; Coheur, P.-F.


    We analyze the ozone (O3) variability in the troposphere (from ground to 300 hPa) using 8 years (January 2008 to March 2016) of O3 profile measurements provided by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp satellite. The capability of IASI to monitor the year-to-year variability in that layer is examined first in terms of vertical sensitivity, a priori contribution, and correlations in the deseasonalized anomalies with the upper layers. We present global patterns of the main geophysical drivers (e.g., solar flux, Quasi-biennal Oscillation—QBO, North Atlantic Oscillation—NAO, and El Niño-Southern Oscillation—ENSO) of IASI O3 variations, obtained by applying appropriate annual and seasonal multivariate regression models on time series of spatially gridded averaged O3. The results show that the models are able to explain most of the O3 variability captured by IASI. Large O3 changes in the North Arctic/Euro-Atlantic sector and over the equatorial band are attributed to the NAO and the QBO effects, respectively. ENSO is modeled as the main contributor to the O3 variations in the tropical band where direct effects of warm and cool ENSO phases are highlighted with a clear tropical-extratropical gradient. A strong west-east gradient in the tropics is also found and likely reflects an indirect effect related to ENSO dry conditions. Finally, we also show that the ENSO perturbs the O3 variability far from the tropics into middle and high latitudes where a significant 4-month time-lag in the response of O3 to ENSO is identified for the first time.

  12. Decadal Effects of Elevated CO2 and O3 on Forest Soil Respiration and Belowground Carbon Cycling at Aspen FACE

    Talhelm, A. F.; Pregitzer, K. S.; Zak, D. R.; Burton, A. J.


    Three northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and/or tropospheric ozone (O3) for 11 years, advancing from open-grown seedlings 8 m tall. Here, we report results from measurements of soil respiration that occurred during the experiment from 1999 to 2008. In order to better understand this flux, we compare changes in soil respiration to the effects of CO2 and O3 on net primary productivity (NPP), fine root biomass, and leaf litter production. Elevated CO2 enhanced soil respiration by an average of 28%. This stimulation of soil respiration varied from +19% to +44%, but did not change consistently during the 10 year measurement period (r2 = 0.04). The effect of elevated O3 on soil respiration was dynamic. In year two of the experiment (1999), elevated O3 decreased soil respiration by 7%. However, soil respiration consistently increased through time under elevated O3 (r2 = 0.71) and was 9% greater than under ambient O3 in the final year of the experiment (2008). Overall, elevated O3 had no meaningful effect on soil respiration (+0.3%). The annual effects of elevated CO2 on soil respiration were not correlated with NPP or fine root biomass, but was positively correlated with leaf litter production (r = 0.57). Annual leaf litter production was also related to the annual effects of elevated O3 on soil respiration (r = 0.78), but relationship was tighter between annual O3 effects on NPP and soil respiration (r = 0.83).

  13. A matrix-isolation-infrared spectroscopic study of the reactions of nitric oxide with oxygen and ozone

    Bhatia, S. C.; Hall, J. H., Jr.


    An investigation of the oxidation of NO to NO2 by trapping the products of the gas-phase reactions with excess oxygen and ozone identified the transient species by their infrared spectra. The primary products of the NO + NO2 reactions were NO2, N2O3(A), N2O3(B), N2O4, and peroxy nitrate (OONO). The primary products of the NO + O3 reactions were NO2 and peroxy NO3 with the higher nitric oxides in low concentrations compared with the NO + O2 reactions. Isotopic oxygen and ozone were used to identify the infrared absorption frequency of the peroxy nitrate.

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

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


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

  15. Prediction of Mechanism and Thermochemical Properties of O3 + H2S Atmospheric Reaction

    Morteza Vahedpour


    Full Text Available Ozone and hydrogen sulfide reaction mechanism including a complex was studied at the B3LYP/6-311++G(3df,3pd and CCSD/6-311++G(3df,3pd//B3LYP/6-311++G(3df,3pd levels of computation. The interaction between sulfur atom of hydrogen sulfide and terminal oxygen atom of ozone produces a stable H2S-O3 complex with no barrier. With the decomposition of this complex, four possible product channels have been found. Intrinsic reaction coordinate, topological analyses of atom in molecule, and vibrational frequency calculation have been used to confirm the suggested mechanism. Thermodynamic data at T = 298.15 K and the atmospheric pressure have been calculated. The results show that the production of H2O + SO2 is the main reaction channel with ΔG° = −645.84 kJ/mol. Rate constants of H2S + O3 reaction show two product channels, SO2 + H2O and HSO + HOO, which compete with each other based on the temperature.

  16. O2(a1Δ) Quenching In The O/O2/O3 System

    Azyazov, V. N.; Mikheyev, P. A.; Postell, D.; Heaven, M. C.


    The development of discharge singlet oxygen generators (DSOG's) that can operate at high pressures is required for the power scaling of the discharge oxygen iodine laser. In order to achieve efficient high-pressure DSOG operation it is important to understand the mechanisms by which singlet oxygen (O2(a1Δ)) is quenched in these devices. It has been proposed that three-body deactivation processes of the type O2(a1Δ)+O+M→2O2+M provide significant energy loss channels. To further explore these reactions the physical and reactive quenching of O2(a1Δ) in O(3P)/O2/O3/CO2/He/Ar mixtures has been investigated. Oxygen atoms and singlet oxygen molecules were produced by the 248 nm laser photolysis of ozone. The kinetics of O2(a1Δ) quenching were followed by observing the 1268 nm fluorescence of the O2a1Δ-X3∑ transition. Fast quenching of O2(a1Δ) in the presence of oxygen atoms and molecules was observed. The mechanism of the process has been examined using kinetic models, which indicate that quenching by vibrationally excited ozone is the dominant reaction.

  17. Molecular dynamics simulation of gas-phase ozone reactions with sabinene and benzene.

    Ridgway, H F; Mohan, B; Cui, X; Chua, K J; Islam, M R


    Gas-phase reactions of ozone (O3) with volatile organic compounds were investigated both by experiment and molecular simulations. From our experiments, it was found ozone readily reacts with VOC pure components and reduces it effectively. By introducing ozone intermittently, the reaction between VOC and ozone is markedly enhanced. In order to understand the relationship between intermediate reactions and end products, ozone reaction with benzene and alicyclic monoterpene sabinene were simulated via a novel hybrid quantum mechanical/molecular mechanics (QM/MM) algorithm that forced repeated bimolecular collisions. Molecular orbital (MO) rearrangements (manifested as bond dissociation or formation), resulting from the collisions, were computed by semi-empirical unrestricted Hartree-Fock methods (e.g., RM1). A minimum of 975 collisions between ozone and targeted organic species were performed to generate a distribution of reaction products. Results indicated that benzene and sabinene reacted with ozone to produce a range of stable products and intermediates, including carbocations, ring-scission products, as well as peroxy (HO2 and HO3) and hydroxyl (OH) radicals. Among the stable sabinene products observed included formaldehyde and sabina-ketone, which have been experimentally demonstrated in gas-phase ozonation reactions. Among the benzene ozonation products detected composed of oxygen mono-substituted aromatic C6H5O, which may undergo further transformation or rearrangement to phenol, benzene oxide or 2,4-cyclohexadienone; a phenomenon which has been experimentally observed in vapor-phase photocatalytic ozonation reactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Ozone Enhancement in the Lower Troposphere over Central and Eastern China as Observed from the space

    Maki, T.; Hayashida, S.; Ono, A.; Kayaba, S.; Kajino, M.; Deushi, M.; Sekiyama, T. T.; Yamaji, K.; Liu, X.


    The recent roducts of the Ozone Monitoring Instrument (OMI) retrieved by Liu et al. (2010) revealed spatial and temporal variations in ozone distributions in multiple tropospheric layers. We compared the OMI-derived ozone over Beijing with the airborne measurements conducted by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. The reliability of the OMI ozone retrievals was verified at the lower troposphere under enhanced ozone conditions (Hayashida et al. 2015). Ozone enhancement was clearly observed over Central and Eastern China (CEC), with Shandong Province as its center and most notably in June in any given year. The seasonality of the ozone enhancement was similar throughout the nine-year OMI measurement period of 2005 to 2013. As introduced by Hayashida et al. (2015), we have defined ΔO3 as the difference between the retrieved ozone and a priori value. To identify the area of significant ozone enhancement in further detail, the areas whose ΔO3 show similar seasonal variation were grouped into a cluster using the statistical tool R. As a result, the area covering the provinces of Shandong, Hebei, and Shanxi presents