Ozone pretreatment of process waste water generated in course of fluoroquinolone production.

PubMed

Daoud, Fares; Pelzer, David; Zuehlke, Sebastian; Spiteller, Michael; Kayser, Oliver

2017-10-01

During production of active pharmaceutical ingredients, process waste water is generated at several stages of manufacturing. Whenever possible, the resulting waste water will be processed by conventional waste water treatment plants. Currently, incineration of the process waste water is the method to eliminate compounds with high biological activity. Thus, ozone treatment followed by biological waste water treatment was tested as an alternative method. Two prominent representatives of the large group of fluoroquinolone antibiotics (ciprofloxacin and moxifloxacin) were investigated, focussing on waste water of the bulk production. Elimination of the target compounds and generation of their main transformation products were determined by liquid chromatography - high resolution mass spectrometry (LC-HRMS). The obtained results demonstrated, that the concentration of moxifloxacin and its metabolites can be effectively reduced (>99.7%) prior entering the receiving water. On the contrary, the concentration of ciprofloxacin and its metabolites remained too high for safe discharge, necessitating application of prolonged ozonation for its further degradation. The required ozonation time can be estimated based on the determined kinetics. To assure a low biological activity the ecotoxicity of the ozonated waste water was investigated using three trophic levels. By means of multiple-stage mass spectrometry (MS n ) experiments several new transformation products of the fluoroquinolones were identified. Thus, previously published proposed structures could be corrected or confirmed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of ozonation and biological activated carbon filtration on ceramic membrane fouling.

PubMed

Ibn Abdul Hamid, Khaled; Sanciolo, Peter; Gray, Stephen; Duke, Mikel; Muthukumaran, Shobha

2017-12-01

Ozone pre-treatment (ozonation, ozonisation) and biological activated carbon (BAC) filtration pre-treatment for the ceramic microfiltration (CMF) treatment of secondary effluent (SE) were studied. Ozone pre-treatment was found to result in higher overall removal of UV absorbance (UVA 254 ) and colour, and higher permeability than BAC pre-treatment or the combined use of ozone and BAC (O3+BAC) pre-treatment. The overall removal of colour and UVA 254 by ceramic filtration of the ozone pre-treated water was 97% and 63% respectively, compared to 86% and 48% respectively for BAC pre-treatment and 29% and 6% respectively for the untreated water. Ozone pre-treatment, however, was not effective in removal of dissolved organic carbon (DOC). The permeability of the ozone pre-treated water through the ceramic membrane was found to decrease to 50% of the original value after 200 min of operation, compared to approximately 10% of the original value for the BAC pre-treated, O3+BAC pre-treated water and the untreated water. The higher permeability of the ozone pre-treated water was attributed to the excellent removal of biopolymer particles (100%) and high removal of humic substances (84%). The inclusion of a BAC stage between ozone pre-treatment and ceramic filtration was detrimental. The O3+BAC+CMF process was found to yield higher biopolymer removal (96%), lower humic substance (HS) component removal (66%) and lower normalized permeability (0.1) after 200 min of operation than the O3+CMF process (86%, 84% and 0.5 respectively). This was tentatively attributed to the chemical oxidation effect of ozone on the BAC biofilm and adsorbed components, leading to the generation of foulants that are not generated in the O3+CMF process. This study demonstrated the potential of ozone pre-treatment for reducing organic fouling and thus improving flux for the CMF of SE compared to O3+BAC pre-treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tropospheric ozone simulated by a global-multi-regional two-way coupling model system

NASA Astrophysics Data System (ADS)

Yan, Y.; Lin, J.; Chen, J.; Hu, L.

2015-12-01

Current global chemical transport models are limited by horizontal resolutions (100-500 km), and they cannot capture small-scale processes affecting tropospheric ozone (O3). Here we use a recently built two-way coupling system of GEOS-Chem to simulate the global tropospheric O3 in 2009. The system couples the global model (~ 200 km) and its three nested models (~ 50 km) covering Asia, North America and Europe, respectively. Benefiting from the high resolution, the nested models better capture small-scale processes than the global model alone. In the coupling system, the nested models provide results to modify the global model simulation within respective nested domains while taking the lateral boundary conditions from the global model. Due to the "coupling" effects, the two-way system significantly improves the tropospheric O3 simulation upon the global model alone, as found by comparisons with a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). Compared to the global model alone, the two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean O3 with the ground measurements from 0.53 to 0.68 and reduces the mean model bias from 10.8 to 6.7 ppb. Regionally, the coupled model reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO and MOZAIC data, reducing the tropospheric (0-9 km) mean bias by 3-10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO profiles. The two-way coupled simulation also reduces the global tropospheric column ozone by 3.0 DU (9.5%), bringing them closer to the OMI data in all seasons. Simulation improvements are more significant in the northern hemisphere, and are primarily a result of improved representation of the nonlinear ozone chemistry, including but not limited to urban-rural contrast. The two

Degradation and COD removal of catechol in wastewater using the catalytic ozonation process combined with the cyclic rotating-bed biological reactor.

PubMed

Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

2015-07-01

The effect of ozonation catalyzed with MgO/granular activated carbon (MgO/GAC) composite as a pretreatment process on the performance of cyclic rotating-bed biological reactor (CRBR) for the catechol removal from wastewater has been investigated. CRBR with acclimated biomasses could efficiently remove catechol and its related COD from wastewater at organic loading rate (OLR) of 7.82 kg COD/m(3).d (HRT of 9 h). Then, OLR increased to 15.64 kg COD/m(3).d (HRT of 4.5 h) and CRBR failed. Catalytic ozonation process (COP) used as a pre-treatment and could improve the performance of the failed CRBR. The overall removal efficiency of the combined process attained respective steady states of 91% and 79% for degradation and COD removal of catechol. Therefore, the combined process is more effective in degradation and COD removal of catechol; it is also a viable alternative for upgrading industrial wastewater treatment plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coupling Processes Between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, Malcolm K. W.; Weisenstein, Debra; Rodriguez, Jose; Danilin, Michael; Scott, Courtney; Shia, Run-Lie; Eluszkiewicz, Junusz; Sze, Nien-Dak

1999-01-01

This is the final report. The overall objective of this project is to improve the understanding of coupling processes among atmospheric chemistry, aerosol and climate, all important for quantitative assessments of global change. Among our priority are changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The work emphasizes two important aspects: (1) AER's continued participation in preparation of, and providing scientific input for, various scientific reports connected with assessment of stratospheric ozone and climate. These include participation in various model intercomparison exercises as well as preparation of national and international reports. and (2) Continued development of the AER three-wave interactive model to address how the transport circulation will change as ozone and the thermal properties of the atmosphere change, and assess how these new findings will affect our confidence in the ozone assessment results.

Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

PubMed

Rubalcaba, A; Suárez-Ojeda, M E; Stüber, F; Fortuny, A; Bengoa, C; Metcalfe, I; Font, J; Carrera, J; Fabregat, A

2007-01-01

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.

Effect of ozone on biopolymers in biofiltration and ultrafiltration processes.

PubMed

Siembida-Lösch, Barbara; Anderson, William B; Wang, Yulang Michael; Bonsteel, Jane; Huck, Peter M

2015-03-01

The focus of this full-scale study was to determine the effect of ozone on biopolymer concentrations in biofiltration and ultrafiltration (UF) processes treating surface water from Lake Ontario. Ozonation was out of service for maintenance for 9 months, hence, it was possible to investigate ozone's action on biologically active carbon contactors (BACCs) and UF, in terms of biopolymer removal. Given the importance of biopolymers for fouling, this fraction was quantified using a chromatographic technique. Ozone pre-treatment was observed to positively impact the active biomass in biofilters. However, since an increase of the active biomass did not result in higher biopolymer removal, active biomass concentration cannot be a surrogate for biofiltration performance. It was evident that increasing empty bed contact time (EBCT) from 4 to 19 min only had a positive effect on biopolymer removal through BACCs when ozone was out of service. However, as a mass balance experiment showed, ozone-free operation resulted in higher deposition of biopolymers on a UF membrane and slight deterioration in its performance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bromine-Chlorine Coupling in the Antarctic Ozone Hole

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.; Prather, Michael J.

1996-01-01

The contribution from the chlorine and bromine species in the formation of the Antarctic ozone hole is evaluated. Since chlorine and bromine compounds are of different industrial origin, it is desirable, from a policy point of view, to be able to attribute chlorine-catalyzed loss of ozone with those reactions directly involving chlorine species, and likewise for bromine-catalyzed loss. In the stratosphere, however, most of the chemical families are highly coupled, and, for example, changes in the chlorine abundance will alter the partitioninig in other families and thus the rate of ozone loss. This modeling study examines formation of the Antarctic ozone hole for a wide range of bromine concentrations (5 - 25 pptv) and for chlorine concentrations typical of the last two decades (1.5, 2.5 and 3.5 ppbv). We follow the photochemical evolution of a single parcel of air, typical of the inner Antarctic vortex (50 mbar, 70 deg. S, NO(sub y) = 2 ppbv, with Polar Stratospheric Clouds(PSC)) from August 1 to November 1. For all of these ranges of chlorine and bromine loading, we would predict a substantial ozone hole (local depletion greater than 90%) within the de-nitrified, PSC- perturbed vortex. The contributions of the different catalytic cycles responsible for ozone loss are tabulated. The deep minimum in ozone is driven primarily by the chlorine abundance. As bromine levels decrease, the magnitude of the chlorine-catalyzed ozone loss increases to take up the slack. This is because bromine suppresses ClO by accelerating the conversion of ClO an Cl2O2 back to HCI. For this range of conditions, the local relative efficiency of ozone destruction per bromine atom to that per chlorine atom (alpha-factor) ranges from 33 to 55, decreasing with increase of bromine.

Coupling Processes Between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, Malcolm; Weisenstein, Debra; Rodriquez, Jose; Danilin, Michael; Scott, Courtney; Shia, Run-Lie; Eluszkiewicz, Janusz; Sze, Nien-Dak; Stewart, Richard W. (Technical Monitor)

1999-01-01

This is the final report for NAS5-97039 for work performed between December 1996 and November 1999. The overall objective of this project is to improve the understanding of coupling processes among atmospheric chemistry, aerosol and climate, all important for quantitative assessments of global change. Among our priority are changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The work emphasizes two important aspects: (1) AER's continued participation in preparation of, and providing scientific input for, various scientific reports connected with assessment of stratospheric ozone and climate. These include participation in various model intercomparison exercises as well as preparation of national and international reports. (2) Continued development of the AER three-wave interactive model to address how the transport circulation will change as ozone and the thermal properties of the atmosphere change, and assess how these new findings will affect our confidence in the ozone assessment results.

Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

NASA Astrophysics Data System (ADS)

Yan, Yingying; Lin, Jintai; Chen, Jinxuan; Hu, Lu

2016-02-01

Small-scale nonlinear chemical and physical processes over pollution source regions affect the tropospheric ozone (O3), but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100-500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use the recently built two-way coupling system of the GEOS-Chem CTM to simulate the regional and global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Specifically, the nested models take lateral boundary conditions (LBCs) from the global model, better capture small-scale processes and feed back to modify the global model simulation within the nested domains, with a subsequent effect on their LBCs. Compared to the global model alone, the two-way coupled system better simulates the tropospheric O3 both within and outside the nested domains, as found by evaluation against a suite of ground (1420 sites from the World Data Centre for Greenhouse Gases (WDCGG), the United States National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory Global Monitoring Division (GMD), the Chemical Coordination Centre of European Monitoring and Evaluation Programme (EMEP), and the United States Environmental Protection Agency Air Quality System (AQS)), aircraft (the High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) and Measurement of Ozone and Water Vapor by Airbus In- Service Aircraft (MOZAIC)) and satellite measurements (two Ozone Monitoring Instrument (OMI) products). The two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean surface O3 with the ground measurements

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

Treesearch

Ned Nikolova; Karl F. Zeller

2003-01-01

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

Transformation of Contaminant Candidate List (CCL3) compounds during ozonation and advanced oxidation processes in drinking water: Assessment of biological effects.

PubMed

Mestankova, Hana; Parker, Austa M; Bramaz, Nadine; Canonica, Silvio; Schirmer, Kristin; von Gunten, Urs; Linden, Karl G

2016-04-15

The removal of emerging contaminants during water treatment is a current issue and various technologies are being explored. These include UV- and ozone-based advanced oxidation processes (AOPs). In this study, AOPs were explored for their degradation capabilities of 25 chemical contaminants on the US Environmental Protection Agency's Contaminant Candidate List 3 (CCL3) in drinking water. Twenty-three of these were found to be amenable to hydroxyl radical-based treatment, with second-order rate constants for their reactions with hydroxyl radicals (OH) in the range of 3-8 × 10(9) M(-1) s(-1). The development of biological activity of the contaminants, focusing on mutagenicity and estrogenicity, was followed in parallel with their degradation using the Ames and YES bioassays to detect potential changes in biological effects during oxidative treatment. The majority of treatment cases resulted in a loss of biological activity upon oxidation of the parent compounds without generation of any form of estrogenicity or mutagenicity. However, an increase in mutagenic activity was detected by oxidative transformation of the following CCL3 parent compounds: nitrobenzene (OH, UV photolysis), quinoline (OH, ozone), methamidophos (OH), N-nitrosopyrolidine (OH), N-nitrosodi-n-propylamine (OH), aniline (UV photolysis), and N-nitrosodiphenylamine (UV photolysis). Only one case of formation of estrogenic activity was observed, namely, for the oxidation of quinoline by OH. Overall, this study provides fundamental and practical information on AOP-based treatment of specific compounds of concern and represents a framework for evaluating the performance of transformation-based treatment processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coupling biology and oceanography in models.

PubMed

Fennel, W; Neumann, T

2001-08-01

The dynamics of marine ecosystems, i.e. the changes of observable chemical-biological quantities in space and time, are driven by biological and physical processes. Predictions of future developments of marine systems need a theoretical framework, i.e. models, solidly based on research and understanding of the different processes involved. The natural way to describe marine systems theoretically seems to be the embedding of chemical-biological models into circulation models. However, while circulation models are relatively advanced the quantitative theoretical description of chemical-biological processes lags behind. This paper discusses some of the approaches and problems in the development of consistent theories and indicates the beneficial potential of the coupling of marine biology and oceanography in models.

Fiber-Optic Coupled Lidar Receiver System to Measure Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Harper, David Brent; Elsayed-Ali, Hani

1998-01-01

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

Advanced oxidation process-biological system for wastewater containing a recalcitrant pollutant.

PubMed

Oller, I; Malato, S; Sánchez-Pérez, J A; Maldonado, M I; Gernjak, W; Pérez-Estrada, L A

2007-01-01

Two advanced oxidation processes (AOPs), ozonation and photo-Fenton, combined with a pilot aerobic biological reactor at field scale were employed for the treatment of industrial non-biodegradable saline wastewater (TOC around 200 mgL(-1)) containing a biorecalcitrant compound, alpha-methylphenylglycine (MPG), at a concentration of 500 mgL(-1). Ozonation experiments were performed in a 50-L reactor with constant inlet ozone of 21.9 g m(-3). Solar photo-Fenton tests were carried out in a 75-L pilot plant made up of four compound parabolic collector (CPC) units. The catalyst concentration employed in this system was 20 mgL(-1) of Fe2+ and the H2O2 concentration was kept in the range of 200-500mgL(-1). Complete degradation of MPG was attained after 1,020 min of ozone treatment, while only 195 min were required for photo-Fenton. Samples from different stages of both AOPs were taken for Zahn-Wellens biocompatibility tests. Biodegradability enhancement of the industrial saline wastewater was confirmed (>70% biodegradability). Biodegradable compounds generated during the preliminary oxidative processes were biologically mineralised in a 170-L aerobic immobilised biomass reactor (IBR). The global efficiency of both AOP/biological combined systems was 90% removal of an initial TOC of over 500 mgL(-1).

Indigenous microbes survive in situ ozonation improving biodegradation of dissolved organic matter in aged oil sands process-affected waters.

PubMed

Brown, Lisa D; Pérez-Estrada, Leonidas; Wang, Nan; El-Din, Mohamed Gamal; Martin, Jonathan W; Fedorak, Phillip M; Ulrich, Ania C

2013-11-01

The oil sands industry faces significant challenges in developing effective remediation technologies for process-affected water stored in tailings ponds. Naphthenic acids, a complex mixture of cycloaliphatic carboxylic acids, have been of particular concern because they concentrate in tailings ponds and are a component of the acutely toxic fraction of process water. Ozone treatment has been demonstrated as an effective means of rapidly degrading naphthenic acids, reducing process water toxicity, and increasing its biodegradability following seeding with the endogenous process water bacteria. This study is the first to examine subsequent in situ biodegradation following ozone pretreatment. Two aged oil sands process-affected waters from experimental reclamation tailings ponds were ozonated to reduce the dissolved organic carbon, to which naphthenic acids contributed minimally (<1mgL(-1)). Treatment with an ozone dose of 50mgL(-1) improved the 84d biodegradability of remaining dissolved organic carbon during subsequent aerobic incubation (11-13mgL(-1) removed from aged process-affected waters versus 5mgL(-1) when not pretreated with ozone). The ozone-treated indigenous microbial communities were as capable of degrading organic matter as the same community not exposed to ozone. This supports ozonation coupled with biodegradation as an effective and feasible treatment option. Copyright © 2013 Elsevier Ltd. All rights reserved.

Partial degradation of five pesticides and an industrial pollutant by ozonation in a pilot-plant scale reactor.

PubMed

Maldonado, M I; Malato, S; Pérez-Estrada, L A; Gernjak, W; Oller, I; Doménech, Xavier; Peral, José

2006-11-16

Aqueous solutions of a mixture of several pesticides (alachlor, atrazine, chlorfenvinphos, diuron and isoproturon), considered PS (priority substances) by the European Commission, and an intermediate product of the pharmaceutical industry (alpha-methylphenylglycine, MPG) chosen as a model industrial pollutant, have been degraded at pilot-plant scale using ozonation. This study is part of a large research project [CADOX Project, A Coupled Advanced Oxidation-Biological Process for Recycling of Industrial Wastewater Containing Persistent Organic Contaminants, Contract No.: EVK1-CT-2002-00122, European Commission, http://www.psa.es/webeng/projects/cadox/index.html] founded by the European Union that inquires into the potential coupling between chemical and biological oxidations for the removal of toxic or non-biodegradable contaminants from water. The evolution of pollutant concentration, TOC mineralization, generation of inorganic species and consumption of O3 have been followed in order to visualize the chemical treatment effectiveness. Although complete mineralization is hard to accomplish, and large amounts of the oxidant are required to lower the organic content of the solutions, the possibility of ozonation cannot be ruled out if partial degradation is the final goal wanted. In this sense, Zahn-Wellens biodegradability tests of the ozonated MPG solutions have been performed, and the possibility of a further coupling with a secondary biological treatment for complete organic removal is envisaged.

Application of integrated ozone biological aerated filters and membrane filtration in water reuse of textile effluents.

PubMed

He, Yaozhong; Wang, Xiaojun; Xu, Jinling; Yan, Jinli; Ge, Qilong; Gu, Xiaoyang; Jian, Lei

2013-04-01

A combined process including integrated ozone-BAFs (ozone biological aerated filters) and membrane filtration was first applied for recycling textile effluents in a cotton textile mill with capacity of 5000 m(3)/d. Influent COD (chemical oxygen demand) in the range of 82-120 mg/L, BOD5 (5-day biochemical oxygen demand) of 12.6-23.1 mg/L, suspended solids (SSs) of 38-52 mg/L and color of 32-64° were observed during operation. Outflows with COD≤45 mg/L, BOD5≤7.6 mg/L, SS≤15 mg/L, color≤8° were obtained after being decontaminated by ozone-BAF with ozone dosage of 20-25 mg/L. Besides, the average removal rates of PVA (polyvinyl alcohol) and UV254 were 100% and 73.4% respectively. Permeate water produced by RO (reverse osmosis) could be reused in dyeing and finishing processes, while the RO concentrates could be discharged directly under local regulations with COD≤100 mg/L, BOD5≤21 mg/L, SS≤52 mg/L, color≤32°. Results showed that the combined process could guarantee water reuse with high quality, and solve the problem of RO concentrate disposal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ozone pretreatment of olive mill wastewaters (OMW) and its effect on OMW biochemical methane potential (BMP).

PubMed

Tsintavi, E; Pontillo, N; Dareioti, M A; Kornaros, M

2013-01-01

The possibility of coupling a physicochemical pretreatment (ozonation) with a biological treatment (anaerobic digestion) was investigated for the case of olive mill wastewaters (OMW). Batch ozonation experiments were performed in a glass bubble reactor. The parameters which were tested included the ozone concentration in the inlet gas stream, the reactor temperature and the composition of the liquid medium in terms of raw or fractionated OMW used. In the sequel, ozone-pretreated OMW samples were tested for their biochemical methane potential (BMP) under mesophilic conditions and these results were compared to the BMP of untreated OMW. The ozonation process alone resulted in a 57-76% decrease of total phenols and a 5-18% decrease of total carbohydrates contained in OMW, depending on the experimental conditions. Nevertheless, the ozone-pretreated OMW exhibited lower chemical oxygen demand removal and methane production during BMP testing compared to the untreated OMW.

Degradation alternatives for a commercial fungicide in water: biological, photo-Fenton, and coupled biological photo-Fenton processes.

PubMed

López-Loveira, Elsa; Ariganello, Federico; Medina, María Sara; Centrón, Daniela; Candal, Roberto; Curutchet, Gustavo

2017-11-01

Imazalil (IMZ) is a widely used fungicide for the post-harvest treatment of citrus, classified as "likely to be carcinogenic in humans" for EPA, that can be only partially removed by conventional biological treatment. Consequently, specific or combined processes should be applied to prevent its release to the environment. Biological treatment with adapted microorganism consortium, photo-Fenton, and coupled biological photo-Fenton processes were tested as alternatives for the purification of water containing high concentration of the fungicide and the coadjutants present in the commercial formulation. IMZ-resistant consortium with the capacity to degrade IMZ in the presence of a C-rich co-substrate was isolated from sludge coming from a fruit packaging company wastewater treatment plant. This consortium was adapted to resist and degrade the organics present in photo-Fenton-oxidized IMZ water solution. Bacteria colonies from the consortia were isolated and identified. The effect of H 2 O 2 initial concentration and dosage on IMZ degradation rate, average oxidation state (AOS), organic acid concentration, oxidation, and mineralization percentage after photo-Fenton process was determined. The application of biological treatment to the oxidized solutions notably decreased the total organic carbon (TOC) in solution. The effect of the oxidation degree, limited by H 2 O 2 concentration and dosage, on the percentage of mineralization obtained after the biological treatment was determined and explained in terms of changes in AOS. The concentration of H 2 O 2 necessary to eliminate IMZ by photo-Fenton and to reduce TOC and chemical oxygen demand (COD) by biological treatment, in order to allow the release of the effluents to rivers with different flows, was estimated.

Ozone processing of foods and beverages

USDA-ARS?s Scientific Manuscript database

Ozone has a long history of use as a disinfectant in food and beverage processing. In the United States, the application of ozone to disinfect bottled water was approved as Generally Recognized As Safe (GRAS) in 1982. Later it was approved as a sanitizing agent for bottled water treatment lines. Ozo...

Treatment of azo dye Acid Orange 52 using ozonation and completed-mixed activated sludge process

NASA Astrophysics Data System (ADS)

Abidin, C. Z. A.; Fahmi; Ong, S. A.; Ahmad, R.; Sabri, S. N.

2017-06-01

In this study, the characteristic of colour and COD removal of azo dye Acid Orange 52 (AO52) by ozonation, in combination with complete-mixed activated sludge process (CMAS) was evaluated. The experimentation was arranged in two phases: during the first one, only ozonation was performed, while, during the second phase, it was integrated with CMAS. The performance of colour and COD concentration of AO52 with and without CMAS treatment, is compared and evaluated. From the results, it is obvious that high decolourization from the start of CMAS was contributed from the pre-treatments. The colour removal was due to the fact that ozonation able to cleave the azo bonds that represent colour. Thus, CMAS without pre-treatment are unable to decolourize the dyes sufficiently. 59.6% COD was removed from the first-stage, while merely 9.8% COD fraction removed from the subsequence second-stage CMAS. It is suggested that the rapid COD removal without ozonation are due to activated sludge adsorption processes. The decreased of mixed liquor suspended solids (MLSS) affected the CMAS performances, as the biomass decreased due to lack of nutrient for activated sludge microorganisms to multiply. Results from pre-ozonation alone contributed more than 50% of total COD removal, which indicated that at higher ozone dosage, tend to mineralize azo dye. Thus, ozonation not oxidized the dye though complete mineralization that produce carbon dioxide and water. However, it is a potential process for enhancing colour removal and biodegradability of dye-containing wastewater, once the appropriate ozonation time is determined. Therefore, the role of ozonation seems to break down the dye molecules and created ozonation by-product that is easily biodegraded in the subsequent biological treatment.

A hybrid process combining homogeneous catalytic ozonation and membrane distillation for wastewater treatment.

PubMed

Zhang, Yong; Zhao, Peng; Li, Jie; Hou, Deyin; Wang, Jun; Liu, Huijuan

2016-10-01

A novel catalytic ozonation membrane reactor (COMR) coupling homogeneous catalytic ozonation and direct contact membrane distillation (DCMD) was developed for refractory saline organic pollutant treatment from wastewater. An ozonation process took place in the reactor to degrade organic pollutants, whilst the DCMD process was used to recover ionic catalysts and produce clean water. It was found that 98.6% total organic carbon (TOC) and almost 100% salt were removed and almost 100% metal ion catalyst was recovered. TOC in the permeate water was less than 16 mg/L after 5 h operation, which was considered satisfactory as the TOC in the potassium hydrogen phthalate (KHP) feed water was as high as 1000 mg/L. Meanwhile, the membrane distillation flux in the COMR process was 49.8% higher than that in DCMD process alone after 60 h operation. Further, scanning electron microscope images showed less amount and smaller size of contaminants on the membrane surface, which indicated the mitigation of membrane fouling. The tensile strength and FT-IR spectra tests did not reveal obvious changes for the polyvinylidene fluoride membrane after 60 h operation, which indicated the good durability. This novel COMR hybrid process exhibited promising application prospects for saline organic wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of the rates of ozonation of biological antioxidants and oleate and linoleate esters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giamalva, D.; Church, D.F.; Pryor, W.A.

1985-12-17

The rates of reaction with ozone of some biological antioxidants and simple polyunsaturated fatty acids (PUFA) have been measured in water or in aqueous micellar solutions. At pH 7.0 the rate constants are ca. 10(6) M-1 sec-1 for urate, alpha-tocopherol, and PUFA, and 6 X 10(7) M-1 sec-1 for ascorbate. When ozone-containing air is breathed, ascorbate in the lung may undergo direct ozonation. However, alpha-tocopherol is probably spared direct reaction with ozone because it doesn't effectively compete with PUFA in pulmonary membranes; rather, tocopherol is used to scavenge radicals produced from the ozone-PUFA reaction.

Heterogeneous catalytic ozonation of biologically pretreated Lurgi coal gasification wastewater using sewage sludge based activated carbon supported manganese and ferric oxides as catalysts.

PubMed

Zhuang, Haifeng; Han, Hongjun; Hou, Baolin; Jia, Shengyong; Zhao, Qian

2014-08-01

Sewage sludge of biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl₂ as activation agent, which supported manganese and ferric oxides as catalysts (including SBAC) to improve the performance of ozonation of real biologically pretreated Lurgi coal gasification wastewater. The results indicated catalytic ozonation with the prepared catalysts significantly enhanced performance of pollutants removal and the treated wastewater was more biodegradable and less toxic than that in ozonation alone. On the basis of positive effect of higher pH and significant inhibition of radical scavengers in catalytic ozonation, it was deduced that the enhancement of catalytic activity was responsible for generating hydroxyl radicals and the possible reaction pathway was proposed. Moreover, the prepared catalysts showed superior stability and most of toxic and refractory compounds were eliminated at successive catalytic ozonation runs. Thus, the process with economical, efficient and sustainable advantages was beneficial to engineering application. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coupling Processes Between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, Malcolm K. W.; Weisenstein, Debra; Shia, Run-Lie; Sze, N. D.

1998-01-01

The overall objective of this project is to improve the understanding of coupling processes between atmospheric chemistry and climate. Model predictions of the future distributions of trace gases in the atmosphere constitute an important component of the input necessary for quantitative assessments of global change. We will concentrate on the changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The key modeling tools for this work are the AER 2-dimensional chemistry-transport model, the AER 2-dimensional stratospheric sulfate model, and the AER three-wave interactive model with full chemistry. We will continue developing our three-wave model so that we can help NASA determine the strength and weakness of the next generation assessment models.

Coupling Processes Between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, M. K. W.; Weisenstein, Debra; Shia, Run-Lie; Sze, N. D.

1998-01-01

The overall objective of this project is to improve the understanding of coupling processes between atmospheric chemistry and climate. Model predictions of the future distributions of trace gases in the atmosphere constitute an important component of the input necessary for quantitative assessments of global change. We will concentrate on the changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The key modeling tools for this work are the AER two-dimensional chemistry-transport model, the AER two-dimensional stratospheric sulfate model, and the AER three-wave interactive model with full chemistry. We will continue developing our three-wave model so that we can help NASA determine the strength and weakness of the next generation assessment models.

MBR/RO/ozone processes for TFT-LCD industrial wastewater treatment and recycling.

PubMed

Chen, T K; Ni, C H; Chan, Y C; Lu, M C

2005-01-01

This research is mainly to explore the treatment capacity for TFT-LCD industrial wastewater recycling by the processes combined with membrane bioreactor (MBR), reverse osmosis (RO) and ozone(O3). The organic wastewater from the TFT-LCD industry was selected as the target. MBR, RO and ozone plants were established for evaluation. An MBR plant consisted of a 2-stage anoxic/aerobic bioreactor and an immersed UF membrane unit was employed. The effluent of MBR was conducted into the RO system then into the ozone system. The RO system consisted of a spiral membrane in the vessel. One bubble column, 75 cm high and diameter 5 cm, were used as the ozonation reactor. On the bottom of ozonation reactor is a porous diffuser for releasing gas, with an aperture of 100 microm (0.1 cm). Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 98.5%. For the TOC item, the average removal efficiency was 97.4%. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of an immersed UF membrane device incorporated with the biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After the treatment of RO, excellent water quality was found. The water quality of permeate was under 5 mg/I, 2 mg/l and 50 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled and reused for the cooling tower make-up water or other purposes. After the treatment of ozone, the treated water quality was under 5 mg/l and 0.852 mg/l for COD and TOC respectively. The test results of MBR, MBR/RO and MBR/RO/ozone processes were compared as possible appropriate treatment technologies applied in TFT-LCD industrial wastewater reuse and recycling.

Global Radiative Forcing of Coupled Tropospheric Ozone and Aerosols in a Unified General Circulation Model

NASA Technical Reports Server (NTRS)

Liao, Hong; Seinfeld, John H.; Adams, Peter J.; Mickley, Loretta J.

2008-01-01

Global simulations of sea salt and mineral dust aerosols are integrated into a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II', that simulates coupled tropospheric ozone-NOx-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols. The fully coupled gas-aerosol unified GCM allows one to evaluate the extent to which global burdens, radiative forcing, and eventually climate feedbacks of ozone and aerosols are influenced by gas-aerosol chemical interactions. Estimated present-day global burdens of sea salt and mineral dust are 6.93 and 18.1 Tg with lifetimes of 0.4 and 3.9 days, respectively. The GCM is applied to estimate current top of atmosphere (TOA) and surface radiative forcing by tropospheric ozone and all natural and anthropogenic aerosol components. The global annual mean value of the radiative forcing by tropospheric ozone is estimated to be +0.53 W m(sup -2) at TOA and +0.07 W m(sup -2) at the Earth's surface. Global, annual average TOA and surface radiative forcing by all aerosols are estimated as -0.72 and -4.04 W m(sup -2), respectively. While the predicted highest aerosol cooling and heating at TOA are -10 and +12 W m(sup -2) respectively, surface forcing can reach values as high as -30 W m(sup -2), mainly caused by the absorption by black carbon, mineral dust, and OC. We also estimate the effects of chemistry-aerosol coupling on forcing estimates based on currently available understanding of heterogeneous reactions on aerosols. Through altering the burdens of sulfate, nitrate, and ozone, heterogeneous reactions are predicted to change the global mean TOA forcing of aerosols by 17% and influence global mean TOA forcing of tropospheric ozone by 15%.

A MODELING AND SIMULATION LANGUAGE FOR BIOLOGICAL CELLS WITH COUPLED MECHANICAL AND CHEMICAL PROCESSES

PubMed Central

Somogyi, Endre; Glazier, James A.

2017-01-01

Biological cells are the prototypical example of active matter. Cells sense and respond to mechanical, chemical and electrical environmental stimuli with a range of behaviors, including dynamic changes in morphology and mechanical properties, chemical uptake and secretion, cell differentiation, proliferation, death, and migration. Modeling and simulation of such dynamic phenomena poses a number of computational challenges. A modeling language describing cellular dynamics must naturally represent complex intra and extra-cellular spatial structures and coupled mechanical, chemical and electrical processes. Domain experts will find a modeling language most useful when it is based on concepts, terms and principles native to the problem domain. A compiler must then be able to generate an executable model from this physically motivated description. Finally, an executable model must efficiently calculate the time evolution of such dynamic and inhomogeneous phenomena. We present a spatial hybrid systems modeling language, compiler and mesh-free Lagrangian based simulation engine which will enable domain experts to define models using natural, biologically motivated constructs and to simulate time evolution of coupled cellular, mechanical and chemical processes acting on a time varying number of cells and their environment. PMID:29303160

A MODELING AND SIMULATION LANGUAGE FOR BIOLOGICAL CELLS WITH COUPLED MECHANICAL AND CHEMICAL PROCESSES.

PubMed

Somogyi, Endre; Glazier, James A

2017-04-01

Biological cells are the prototypical example of active matter. Cells sense and respond to mechanical, chemical and electrical environmental stimuli with a range of behaviors, including dynamic changes in morphology and mechanical properties, chemical uptake and secretion, cell differentiation, proliferation, death, and migration. Modeling and simulation of such dynamic phenomena poses a number of computational challenges. A modeling language describing cellular dynamics must naturally represent complex intra and extra-cellular spatial structures and coupled mechanical, chemical and electrical processes. Domain experts will find a modeling language most useful when it is based on concepts, terms and principles native to the problem domain. A compiler must then be able to generate an executable model from this physically motivated description. Finally, an executable model must efficiently calculate the time evolution of such dynamic and inhomogeneous phenomena. We present a spatial hybrid systems modeling language, compiler and mesh-free Lagrangian based simulation engine which will enable domain experts to define models using natural, biologically motivated constructs and to simulate time evolution of coupled cellular, mechanical and chemical processes acting on a time varying number of cells and their environment.

Enhanced treatment of secondary municipal wastewater effluent: comparing (biological) filtration and ozonation in view of micropollutant removal, unselective effluent toxicity, and the potential for real-time control.

PubMed

Chys, Michael; Demeestere, Kristof; Ingabire, Ange Sabine; Dries, Jan; Van Langenhove, Herman; Van Hulle, Stijn W H

2017-07-01

Ozonation and three (biological) filtration techniques (trickling filtration (TF), slow sand filtration (SSF) and biological activated carbon (BAC) filtration) have been evaluated in different combinations as tertiary treatment for municipal wastewater effluent. The removal of 18 multi-class pharmaceuticals, as model trace organic contaminants (TrOCs), has been studied. (Biological) activated carbon filtration could reduce the amount of TrOCs significantly (>99%) but is cost-intensive for full-scale applications. Filtration techniques mainly depending on biodegradation mechanisms (TF and SSF) are found to be inefficient for TrOCs removal as a stand alone technique. Ozonation resulted in 90% removal of the total amount of quantified TrOCs, but a post-ozonation step is needed to cope with an increased unselective toxicity. SSF following ozonation showed to be the only technique able to reduce the unselective toxicity to the same level as before ozonation. In view of process control, innovative correlation models developed for the monitoring and control of TrOC removal during ozonation, are verified for their applicability during ozonation in combination with TF, SSF or BAC. Particularly for the poorly ozone reactive TrOCs, statistically significant models were obtained that correlate TrOC removal and reduction in UVA 254 as an online measured surrogate parameter.

Model development for naphthenic acids ozonation process.

PubMed

Al Jibouri, Ali Kamel H; Wu, Jiangning

2015-02-01

Naphthenic acids (NAs) are toxic constituents of oil sands process-affected water (OSPW) which is generated during the extraction of bitumen from oil sands. NAs consist mainly of carboxylic acids which are generally biorefractory. For the treatment of OSPW, ozonation is a very beneficial method. It can significantly reduce the concentration of NAs and it can also convert NAs from biorefractory to biodegradable. In this study, a factorial design (2(4)) was used for the ozonation of OSPW to study the influences of the operating parameters (ozone concentration, oxygen/ozone flow rate, pH, and mixing) on the removal of a model NAs in a semi-batch reactor. It was found that ozone concentration had the most significant effect on the NAs concentration compared to other parameters. An empirical model was developed to correlate the concentration of NAs with ozone concentration, oxygen/ozone flow rate, and pH. In addition, a theoretical analysis was conducted to gain the insight into the relationship between the removal of NAs and the operating parameters.

Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse.

PubMed

Zou, Xiao-Ling

2015-06-01

Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

NASA Astrophysics Data System (ADS)

Yan, Y.; Lin, J.; Hu, L.; Chen, J.

2016-12-01

Small-scale nonlinear chemical and physical processes over pollution source regions affect the tropospheric ozone, but these processes are not captured by current global chemical transport models and chemistry-climate models that are limited by coarse horizontal resolutions. These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use a recently built two-way coupling system of the GEOS-Chem CTM to simulate the regional and global tropospheric O3in 2009. The system couples the global model (at 2.5º long. x 2º lat.) and its three nested models (at 0.667º long. x 0.5º lat.) covering Asia, North America and Europe, respectively. Specifically, the nested models take lateral boundary conditions from the global model, better capture small-scale processes, and feed back to modify the global model simulation within the nested domains, with a subsequent effect on their LBCs. Compared to the global model alone, the two-way coupled system better simulates the tropospheric O3 both within and outside the nested domains, as found by evaluation against a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). The two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean surface O3 with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb. Regionally, the coupled system reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3vertical profiles much closer to the HIPPO (for remote areas) and MOZAIC (for polluted regions) data, reducing the tropospheric mean bias by 3-10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO profiles. The two-way coupled simulation also reduces the global tropospheric column ozone by 3.0 DU (9.5%, annual mean), bringing them closer to the OMI data in all

The impact of ozone treatment on changes in biologically active substances of cardamom seeds.

PubMed

Joanna Brodowska, Agnieszka; Śmigielski, Krzysztof; Nowak, Agnieszka; Brodowska, Katarzyna; Catthoor, Rik; Czyżowska, Agata

2014-09-01

The overall objective of this study was to develop a decontamination method against microorganisms in cardamom (Elettaria cardamomum (L.) Maton) seeds using ozone as a decontaminating agent. Ozone treatment was conducted 3 times, at 24-h intervals, and the parameters of the process were determined assuring the least possible losses of biologically active substances (essential oils and polyphenols): ozone concentration 160 to 165.0 g/m(3) ; flow rate 0.1 L/min; pressure 0.5 atm; time 30 min. After each step of decontamination, the microbiological profile of the cardamom seeds was studied, and the contaminating microflora was identified. Next to the microbiological profile, the total polyphenol content (TPC), composition of essential oils, free radical-scavenging capacity, total antioxidant capacity, ferric-reducing antioxidant power (FRAP), and LC-MS polyphenol analysis were determined. This study shows that extract from cardamom seeds after ozone treatment is characterized by a better radical scavenging activity (IC(50) = 24.18 ± 0.04 mg/mL) than the control sample (IC(50) = 31.94 ± 0.05 mg/mL). The extract from cardamom seeds after ozone treatment showed an improved FRAP activity as well (613.64 ± 49.79 mmol TE/g compared to 480.29 ± 30.91 mmol TE/g of control sample). The TPC and the total antioxidant capacity were negatively affected, respectively, 41.2% and 16.2%, compared to the control sample. © 2014 Institute of Food Technologists®

Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

NASA Astrophysics Data System (ADS)

Yan, Y.-Y.; Lin, J.-T.; Chen, J.; Hu, L.

2015-09-01

Small-scale nonlinear chemical and physical processes over pollution source regions affect the global ozone (O3) chemistry, but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100-500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use a recently built two-way coupling system of the GEOS-Chem CTM to simulate the global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Benefiting from the high resolution, the nested models better capture small-scale processes than the global model alone. In the coupling system, the nested models provide results to modify the global model simulation within respective nested domains while taking the lateral boundary conditions from the global model. Due to the "coupling" effects, the two-way system significantly improves the tropospheric O3 simulation upon the global model alone, as found by comparisons with a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). Compared to the global model alone, the two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean O3 with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb in annual average afternoon O3. Regionally, the coupled model reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO (for remote areas) and MOZAIC (for polluted regions) data, reducing the tropospheric (0-9 km) mean bias by 3-10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO

Tropospheric Ozone Lidar Network (TOLNet) Observations of Processes Controlling Spatio-Temporal Tropospheric-Ozone Distributions

NASA Astrophysics Data System (ADS)

Newchurch, M.; Johnson, M. S.; Leblanc, T.; Langford, A. O.; Senff, C. J.; Kuang, S.; Strawbridge, K. B.; McGee, T. J.; Berkoff, T.; Chen, G.

2017-12-01

The Tropospheric Ozone Lidar Network, TOLNet, has matured into a credible scientific group of six ozone lidars that are capable of accurate, high-spatio-temporal-resolution measurement of tropospheric ozone structures and morphology These lidars have demonstrated their 10% accuracy in several intercomparison campaigns and have participated in several scientific investigations both in small and large instrumentation groups. They have investigated many scientific phenomena including stratosphere-to-troposphere exchange, boundary-layer development, the interaction between the boundary layer and the free troposphere, Front-range-ozone morphology, urban outflow, land/sea interactions, et al. These processes determine the ozone distribution affecting large portions of the population. The TOLNet group is now making significant contributions to the innovation of ozone lidar instrumentation and retrieval techniques. The campaigns proposed over the next few years build on demonstrated capability to address more difficult scientific issues, especially the ozone production potential and distribution from wildfires and prescribed burns. Through scientific cooperation with other ground-based profiling instrumentation, TOLNet is also contributing to the validation of the new measurement capabilities of TEMPO.

Coupling Processes between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, M. K. W.; Weisenstein, Debra; Shia, Run-Lie; Sze, N. D.

1998-01-01

This is the third semi-annual report for NAS5-97039, covering January through June 1998. The overall objective of this project is to improve the understanding of coupling processes between atmospheric chemistry and climate. Model predictions of the future distributions of trace gases in the atmosphere constitute an important component of the input necessary for quantitative assessments of global change. We will concentrate on the changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The key modeling for this work are the AER 2-dimensional chemistry-transport model, the AER 2-dimensional stratospheric sulfate model, and the AER three-wave interactive model with full chemistry. We will continue developing our three-wave model so that we can help NASA determine the strengths and weaknesses of the next generation assessment models.

Advanced treatment of biologically pretreated coal chemical industry wastewater using the catalytic ozonation process combined with a gas-liquid-solid internal circulating fluidized bed reactor.

PubMed

Li, Zhipeng; Liu, Feng; You, Hong; Ding, Yi; Yao, Jie; Jin, Chao

2018-04-01

This paper investigated the performance of the combined system of catalytic ozonation and the gas-liquid-solid internal circulating fluidized bed reactor for the advanced treatment of biologically pretreated coal chemical industry wastewater (CCIW). The results indicated that with ozonation alone for 60min, the removal efficiency of chemical oxygen demand (COD) could reach 34%. The introduction of activated carbon, pumice, γ-Al 2 O 3 carriers improved the removal performance of COD, and the removal efficiency was increased by 8.6%, 4.2%, 2%, respectively. Supported with Mn, the catalytic performance of activated carbon and γ-Al 2 O 3 were improved significantly with COD removal efficiencies of 46.5% and 41.3%, respectively; however, the promotion effect of pumice supported with Mn was insignificant. Activated carbon supported with Mn had the best catalytic performance. The catalytic ozonation combined system of MnO X /activated carbon could keep ozone concentration at a lower level in the liquid phase, and promote the transfer of ozone from the gas phase to the liquid phase to improve ozonation efficiency.

Robust impact of coupled stratospheric ozone chemistry on the response of the Austral circulation to increased greenhouse gases

NASA Astrophysics Data System (ADS)

Chiodo, G.; Polvani, L. M.

2016-12-01

Due to computational constraints, interactive stratospheric chemistry is commonly neglected in most GCMs participating in inter-comparison projects. The impact of this simplification on the modeled response to external forcings remains largely unexplored. In this work, we examine the impact of the stratospheric chemistry coupling on the SH circulation response to an abrupt quadrupling of CO2. We accomplish this with a version of the Whole Atmosphere Community Climate (WACCM) model, which allows coupling and de-coupling stratospheric chemistry, without altering any other physical parameterization. We find that the chemistry coupling in WACCM significantly reduces (by about 20%) the response of both eddy-driven mid-latitude jet and the Hadley Cell strength, without altering the surface temperature response. This behavior is linked to the representation of stratospheric ozone, and its effects on the meridional temperature gradient at the extratropical tropopause. Our results imply that neglecting stratospheric ozone chemistry results in a potential overestimation of the circulation response to GHGs. Hence, stratospheric ozone chemistry produces a substantial negative feedback on the response of the atmospheric circulation to increased greenhouse gases.

Chemical oxidation for mitigation of UV-quenching substances (UVQS) from municipal landfill leachate: Fenton process versus ozonation.

PubMed

Jung, Chanil; Deng, Yang; Zhao, Renzun; Torrens, Kevin

2017-01-01

UV-quenching substance (UVQS), as an emerging municipal solid waste (MSW)-derived leachate contaminant, has a potential to interfere with UV disinfection when leachate is disposed of at publicly owned treatment works (POTWs). The objective of this study was to evaluate and compare two chemical oxidation processes under different operational conditions, i.e. Fenton process and ozonation, for alleviation of UV 254 absorbance of a biologically pre-treated landfill leachate. Results showed that leachate UV 254 absorbance was reduced due to the UVQS decomposition by hydroxyl radicals (·OH) during Fenton treatment, or by ozone (O 3 ) and ·OH during ozonation. Fenton process exhibited a better treatment performance than ozonation under their respective optimal conditions, because ·OH could effectively decompose both hydrophobic and hydrophilic dissolved organic matter (DOM), but O 3 tended to selectively oxidize hydrophobic compounds alone. Different analytical techniques, including molecular weight (MW) fractionation, hydrophobic/hydrophilic isolation, UV spectra scanning, parallel factor (PARAFAC) analysis, and fluorescence excitation-emission matrix spectrophotometry, were used to characterize UVQS. After either oxidation treatment, residual UVQS was more hydrophilic with a higher fraction of low MW molecules. It should be noted that the removed UV 254 absorbance (ΔUV 254 ) was directly proportional to the removed COD (ΔCOD) for the both treatments (Fenton process: ΔUV 254  = 0.011ΔCOD; ozonation: ΔUV 254  = 0.016ΔCOD). A greater ΔUV 254 /ΔCOD was observed for ozonation, suggesting that oxidant was more efficiently utilized during ozonation than in Fenton treatment for mitigation of the UV absorbance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tropospheric Ozone Lidar Network (TOLNet) - Long-term Tropospheric Ozone and Aerosol Profiling for Satellite Continuity and Process Studies

NASA Astrophysics Data System (ADS)

Newchurch, M.; Al-Saadi, J. A.; Alvarez, R. J.; Burris, J.; Cantrell, W.; Chen, G.; De Young, R.; Hardesty, R.; Hoff, R. M.; Kaye, J. A.; kuang, S.; Langford, A. O.; LeBlanc, T.; McDermid, I. S.; McGee, T. J.; Pierce, R.; Senff, C. J.; Sullivan, J. T.; Szykman, J.; Tonnesen, G.; Wang, L.

2012-12-01

An interagency research initiative for ground-based ozone and aerosol lidar profiling recently funded by NASA has important applications to air-quality studies in addition to the goal of serving the GEO-CAPE and other air-quality missions. Ozone is a key trace-gas species, a greenhouse gas, and an important pollutant in the troposphere. High spatial and temporal variability of ozone affected by various physical and photochemical processes motivates the high spatio-temporal lidar profiling of tropospheric ozone for improving the simulation and forecasting capability of the photochemical/air-quality models, especially in the boundary layer where the resolution and precision of satellite retrievals are fundamentally limited. It is well known that there are large discrepancies between the surface and upper-air ozone due to titration, surface deposition, diurnal processes, free-tropospheric transport, and other processes. Near-ground ozone profiling has been technically challenging for lidars due to some engineering difficulties, such as near-range saturation, field-of-view overlap, and signal processing issues. This initiative provides an opportunity for us to solve those engineering issues and redesign the lidars aimed at long-term, routine ozone/aerosol observations from the near surface to the top of the troposphere at multiple stations (i.e., NASA/GSFC, NASA/LaRC, NASA/JPL, NOAA/ESRL, UAHuntsville) for addressing the needs of NASA, NOAA, EPA and State/local AQ agencies. We will present the details of the science investigations, current status of the instrumentation development, data access/protocol, and the future goals of this lidar network. Ozone lidar/RAQMS comparison of laminar structures.

Treatment of raw and ozonated oil sands process-affected water under decoupled denitrifying anoxic and nitrifying aerobic conditions: a comparative study.

PubMed

Xue, Jinkai; Zhang, Yanyan; Liu, Yang; Gamal El-Din, Mohamed

2016-11-01

Batch experiments were performed to evaluate biodegradation of raw and ozonated oil sands process-affected water (OSPW) under denitrifying anoxic and nitrifying aerobic conditions for 33 days. The results showed both the anoxic and aerobic conditions are effective in degrading OSPW classical and oxidized naphthenic acids (NAs) with the aerobic conditions demonstrating higher removal efficiency. The reactors under nitrifying aerobic condition reduced the total classical NAs of raw OSPW by 69.1 %, with better efficiency for species of higher hydrophobicity. Compared with conventional aerobic reactor, nitrifying aerobic condition substantially shortened the NA degradation half-life to 16 days. The mild-dose ozonation remarkably accelerated the subsequent aerobic biodegradation of classical NAs within the first 14 days, especially for those with long carbon chains. Moreover, the ozone pretreatment enhanced the biological removal of OSPW classical NAs by leaving a considerably lower final residual concentration of 10.4 mg/L under anoxic conditions, and 5.7 mg/L under aerobic conditions. The combination of ozonation and nitrifying aerobic biodegradation removed total classical NAs by 76.5 % and total oxy-NAs (O3-O6) by 23.6 %. 454 Pyrosequencing revealed that microbial species capable of degrading recalcitrant hydrocarbons were dominant in all reactors. The most abundant genus in the raw and ozonated anoxic reactors was Thauera (~56 % in the raw OSPW anoxic reactor, and ~65 % in the ozonated OSPW anoxic reactor); whereas Rhodanobacter (~40 %) and Pseudomonas (~40 %) dominated the raw and ozonated aerobic reactors, respectively. Therefore, the combination of mild-dose ozone pretreatment and subsequent biological process could be a competent choice for OSPW treatment.

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

PubMed

Leiknes, T; Lazarova, M; Odegaard, H

2005-01-01

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

EFFECTS OF OZONE ON ROOT PROCESSES

EPA Science Inventory

Ozone alters root growth and root processes by first reducing photosynthesis and altering foliar metabolic pathways. The alteration in foliar metabolism is reflected in lowered carbohydrate levels in the roots. This can reduce key metabolic processes such as mineral uptake and sy...

Ozone process insights from field experiments - part I: overview

NASA Astrophysics Data System (ADS)

Hidy, G. M.

This paper gives an overview of selected approaches recently adopted to analyze observations from field experiments that characterize the tropospheric physics and chemistry of ozone and related oxidation products. Analysis of ambient oxidant and precursor concentration measurements, combined with meteorological observations, has provided important information about tropospheric processes. Projection of the response of tropospheric ozone concentrations to changes in precursor emissions is achieved through emissions based air quality models (AQMs). These models integrate several "process" elements from source emissions to meteorological and chemical phenomena. Through field campaigns, new knowledge has become available which has enabled workers to better understand the strengths and weaknesses of AQMs and their components. Examples of insightful results include: (a) reconciliation of ambient concentrations of speciated volatile organic compounds (VOCs) with estimates from emissions models, and inventories, (b) verification of chemical mechanisms for ozone formation from its precursors using approximations applicable in different chemical regimes, (c) inference of regimes of sensitivity in ozone concentration to changes in VOC and NO x precursors from ozone management practices, (d) conceptualization of important air mass transport and mixing processes on different spatial and temporal scales that affect ozone and precursor concentrations distributions, and (e) application of the analysis of spatial and temporal variance to infer the origins of chemical product transport, and precursor distributions. Studies from the first category have been used to improve emissions models substantially over previous forms. The remainder of the analyses has yielded valuable insight into the chemical and meteorological mechanisms at work on different spatial and temporal scales. The methods have provided an observationally based framework for effective choices to improve ozone

Enhanced hydroxyl radical generation in the combined ozonation and electrolysis process using carbon nanotubes containing gas diffusion cathode.

PubMed

Wu, Donghai; Lu, Guanghua; Zhang, Ran; Lin, Qiuhong; Yan, Zhenhua; Liu, Jianchao; Li, Yi

2015-10-01

Combination of ozone together with electrolysis (ozone-electrolysis) is a promising wastewater treatment technology. This work investigated the potential use of carbon nanotube (CNT)-based gas diffusion cathode (GDC) for ozone-electrolysis process employing hydroxyl radicals (·OH) production as an indicator. Compared with conventional active carbon (AC)-polytetrafluoroethylene (PTFE) and carbon black (CB)-PTFE cathodes, the production of ·OH in the coupled process was improved using CNTs-PTFE GDC. Appropriate addition of acetylene black (AB) and pore-forming agent Na2SO4 could enhance the efficiency of CNTs-PTFE GDC. The optimum GDC composition was obtained by response surface methodology (RSM) analysis and was determined as CNTs 31.2 wt%, PTFE 60.6 wt%, AB 3.5 wt%, and Na2SO4 4.7 wt%. Moreover, the optimized CNT-based GDC exhibited much more effective than traditional Ti and graphite cathodes in Acid Orange 7 (AO7) mineralization and possessed the desirable stability without performance decay after ten times reaction. The comparison tests revealed that peroxone reaction was the main pathway of ·OH production in the present system, and cathodic reduction of ozone could significantly promote ·OH generation. These results suggested that application of CNT-based GDC offers considerable advantages in ozone-electrolysis of organic wastewater.

Vibronic coupling and selectivity of vibrational excitation in the negative ion resonances of ozone

NASA Astrophysics Data System (ADS)

Allan, Michael; Popovic̀, Duška B.

1997-04-01

A recent experimental paper reported two shape resonances in electron impact on ozone, A 1 and B 2, both causing vibrational excitation with a distinct pattern of selectivity. The present Letter attempts to rationalize this selectivity using approximate potential curves, calculated for the A 1 and B 2 resonances by adding the SCF energy of neutral ozone to electron attachment energies calculated from ab initio virtual orbital energies using the Koopmans' theorem and an empirical scaling relation. The slopes of the curves explain the efficient excitation of the symmetric stretch by both resonances and the lack of the bending excitation by the B 2 resonance. The A 1 and B 2 resonances are strongly coupled by the b 2 antisymmetric stretch vibration, causing a double minimum on the lower surface. Nonadiabatic effects caused by the strong vibronic coupling explain the observed excitation of the antisymmetric stretch vibration.

On the Complex Coupling Between the Production of Ozone and Secondary Organic Aerosol in Polluted Urban Regions

NASA Astrophysics Data System (ADS)

Stewart, D. R.; Stockwell, W. R.; Morris, V. R.; Fitzgerald, R. M.

2016-12-01

The major photochemical processes that produce ozone and aerosols are coupled together strongly in the polluted urban atmosphere. Aerosols are either directly emitted or formed through the same kind of chemistry that leads to the production of ozone. The aerosols produced through atmospheric chemistry are known as secondary aerosols and they may be composed of inorganic (nitrates, sulfates) or organic compounds. Wind blown dust and soot are two examples of primary aerosols. The component of secondary inorganic aerosols includes compounds such as ammonium nitrate, ammonium bisulfate and ammonium sulfate. Secondary organic aerosols are a very important component of PM with strong implications for health. The formation of secondary organic aerosol is linked with ozone photochemistry through the reactions of volatile organic compounds (VOC). The oxidation of VOC produces radicals that convert nitric oxide to nitrogen dioxide that photolyze to produce ozone. Larger VOC (those with more carbon atoms) undergo a number of oxidation cycles that add oxygen atoms to large organic molecules. The vapor pressure of many of these highly oxidized compounds is sufficiently low that they condense to produce secondary organic aerosols. The Community Multi-scale Air Quality model (CMAQ) and other chemical simulations have been made to quantify the relationship between varying emissions of VOC and NOx and the production of inorganic and secondary organic aerosols. The results from this analysis will be presented.

Ozone production process in pulsed positive dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Ono, Ryo; Oda, Tetsuji

2007-01-01

The ozone production process in a pulsed positive dielectric barrier discharge (DBD) is studied by measuring the spatial distribution of ozone density using a two-dimensional laser absorption method. DBD occurs in a 6 mm point-to-plane gap with a 1 mm-thick glass plate placed on the plane electrode. First, the propagation of DBD is observed using a short-gated ICCD camera. It is shown that DBD develops in three phases: primary streamer, secondary streamer and surface discharge phases. Next, the spatial distribution of ozone density is measured. It is shown that ozone is mostly produced in the secondary streamer and surface discharge, while only a small amount of ozone is produced in the primary streamer. The rate coefficient of the ozone production reaction, O + O2 + M → O3 + M, is estimated to be 2.5 × 10-34 cm6 s-1.

Characterizing the Vertical Processes of Ozone in Colorado's Front Range Using the GSFC Ozone Dial

NASA Technical Reports Server (NTRS)

Sullivan, John T.; McGee, Thomas J.; Hoff, Raymond M.; Sumnicht, Grant; Twigg, Laurence

2015-01-01

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 TROPOZDIAL) 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 a loft 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.

Removal and toxicity reduction of naphthenic acids by ozonation and combined ozonation-aerobic biodegradation.

PubMed

Vaiopoulou, Eleni; Misiti, Teresa M; Pavlostathis, Spyros G

2015-03-01

A commercial naphthenic acids (NAs) mixture (TCI Chemicals) and five model NA compounds were ozonated in a semibatch mode. Ozonation of 25 and 35 mg/L NA mixture followed pseudo first-order kinetics (k(obs)=0.11±0.008 min(-1); r(2)=0.989) with a residual NAs concentration of about 5 mg/L. Ozone reacted preferentially with NAs of higher cyclicity and molecular weight and decreased both cyclicity and the acute Microtox® toxicity by 3.3-fold. The ozone reactivity with acyclic and monocyclic model NAs varied and depended on other structural features, such as branching and the presence of tertiary or quaternary carbons. Batch aerobic degradation of unozonated NA mixture using a NA-enriched culture resulted in 83% NA removal and a 6.7-fold decrease in toxicity, whereas a combination of ozonation-biodegradation resulted in 89% NA removal and a 15-fold decrease in toxicity. Thus, ozonation of NA-bearing waste streams coupled with biodegradation are effective treatment processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coupling Processes Between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, M. K. W.; Weisenstein, Debra; Shia, Run-Li; Sze, N. D.

1997-01-01

This is the first semi-annual report for NAS5-97039 summarizing work performed for January 1997 through June 1997. Work in this project is related to NAS1-20666, also funded by NASA ACMAP. The work funded in this project also benefits from work at AER associated with the AER three-dimensional isentropic transport model funded by NASA AEAP and the AER two-dimensional climate-chemistry model (co-funded by Department of Energy). The overall objective of this project is to improve the understanding of coupling processes between atmospheric chemistry and climate. Model predictions of the future distributions of trace gases in the atmosphere constitute an important component of the input necessary for quantitative assessments of global change. We will concentrate on the changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The key modeling tools for this work are the AER two-dimensional chemistry-transport model, the AER two-dimensional stratospheric sulfate model, and the AER three-wave interactive model with full chemistry.

The Impact of Ozone Treatment in Dynamic Bed Parameters on Changes in Biologically Active Substances of Juniper Berries

PubMed Central

Brodowska, Agnieszka Joanna; Śmigielski, Krzysztof; Nowak, Agnieszka; Czyżowska, Agata; Otlewska, Anna

2015-01-01

The development of the parameters of ozone decontamination method assuring the least possible losses of biologically active substances (essential oils and polyphenols) and their activity in common juniper (Juniperus communis (L.)) berries was studied. Ozone treatment in dynamic bed was conducted 9 times. The process was conducted under different ozone concentrations (100.0; 130.0; 160.0 g O3/m3) and times (30, 60, 90 min). After each decontamination, the microbiological profile of the juniper berries was studied, and the contaminating microflora was identified. Next to the microbiological profile, the phenolic profile, as well as antioxidant activity of extracts and essential oils were determined. The total polyphenol content (TPC), composition of essential oils, free radical-scavenging capacity, total antioxidant capacity, ferric-reducing antioxidant power (FRAP), beta-carotene bleaching test (BCB) and LC-MS polyphenol analysis were carried out. The study reveals that during short ozone contact times, higher amounts of TPC, 15.47 and 12.91 mg CE/g of extract, for samples 100/30 and 130/30, respectively, were demonstrated. Whereas samples 100/60, 130/60, 100/90, and 160/90 exhibited the lowest amount of phenolics. The highest antioxidant activity was found in the methanol extract obtained from ozonated berries which exhibited the lowest IC50 in all the antioxidant assays, such as DPPH, FRAP, and BCB assays. Ozone treatment showed noteworthy potential and its usage in food manufacturing and as an alternative decontamination method should be considered. PMID:26659905

The Impact of Ozone Treatment in Dynamic Bed Parameters on Changes in Biologically Active Substances of Juniper Berries.

PubMed

Brodowska, Agnieszka Joanna; Śmigielski, Krzysztof; Nowak, Agnieszka; Czyżowska, Agata; Otlewska, Anna

2015-01-01

The development of the parameters of ozone decontamination method assuring the least possible losses of biologically active substances (essential oils and polyphenols) and their activity in common juniper (Juniperus communis (L.)) berries was studied. Ozone treatment in dynamic bed was conducted 9 times. The process was conducted under different ozone concentrations (100.0; 130.0; 160.0 g O3/m3) and times (30, 60, 90 min). After each decontamination, the microbiological profile of the juniper berries was studied, and the contaminating microflora was identified. Next to the microbiological profile, the phenolic profile, as well as antioxidant activity of extracts and essential oils were determined. The total polyphenol content (TPC), composition of essential oils, free radical-scavenging capacity, total antioxidant capacity, ferric-reducing antioxidant power (FRAP), beta-carotene bleaching test (BCB) and LC-MS polyphenol analysis were carried out. The study reveals that during short ozone contact times, higher amounts of TPC, 15.47 and 12.91 mg CE/g of extract, for samples 100/30 and 130/30, respectively, were demonstrated. Whereas samples 100/60, 130/60, 100/90, and 160/90 exhibited the lowest amount of phenolics. The highest antioxidant activity was found in the methanol extract obtained from ozonated berries which exhibited the lowest IC50 in all the antioxidant assays, such as DPPH, FRAP, and BCB assays. Ozone treatment showed noteworthy potential and its usage in food manufacturing and as an alternative decontamination method should be considered.

Reduction of Environmental Listeria Using Gaseous Ozone in a Cheese Processing Facility.

PubMed

Eglezos, Sofroni; Dykes, Gary A

2018-05-01

A cheese processing facility seeking to reduce environmental Listeria colonization initiated a regime of ozonation across all production areas as an adjunct to its sanitation regimes. A total of 360 environmental samples from the facility were tested for Listeria over a 12-month period. A total of 15 areas before and 15 areas after ozonation were tested. Listeria isolations were significantly ( P < 0.001) reduced from 15.0% in the preozonation samples to 1.67% in the postozonation samples in all areas. No deleterious effects of ozonation were noted on the wall paneling, seals, synthetic floors, or cheese processing equipment. The ozonation regime was readily incorporated by sanitation staff into the existing good manufacturing practice program. The application of ozone may result in a significant reduction in the prevalence of Listeria in food processing facilities.

Ozonation of oil sands process-affected water accelerates microbial bioremediation.

PubMed

Martin, Jonathan W; Barri, Thaer; Han, Xiumei; Fedorak, Phillip M; El-Din, Mohamed Gamal; Perez, Leonidas; Scott, Angela C; Jiang, Jason Tiange

2010-11-01

Ozonation can degrade toxic naphthenic acids (NAs) in oil sands process-affected water (OSPW), but even after extensive treatment a residual NA fraction remains. Here we hypothesized that mild ozonation would selectively oxidize the most biopersistent NA fraction, thereby accelerating subsequent NA biodegradation and toxicity removal by indigenous microbes. OSPW was ozonated to achieve approximately 50% and 75% NA degradation, and the major ozonation byproducts included oxidized NAs (i.e., hydroxy- or keto-NAs). However, oxidized NAs are already present in untreated OSPW and were shown to be formed during the microbial biodegradation of NAs. Ozonation alone did not affect OSPW toxicity, based on Microtox; however, there was a significant acceleration of toxicity removal in ozonated OSPW following inoculation with native microbes. Furthermore, all residual NAs biodegraded significantly faster in ozonated OSPW. The opposite trend was found for ozonated commercial NAs, which are known to contain no significant biopersistent fraction. Thus, we suggest that ozonation preferentially degraded the most biopersistent OSPW NA fraction, and that ozonation is complementary to the biodegradation capacity of microbial populations in OSPW. The toxicity of ozonated OSPW to higher organisms needs to be assessed, but there is promise that this technique could be applied to accelerate the bioremediation of large volumes of OSPW in Northern Alberta, Canada.

Occurrence of emerging pollutants in urban wastewater and their removal through biological treatment followed by ozonation.

PubMed

Rosal, Roberto; Rodríguez, Antonio; Perdigón-Melón, José Antonio; Petre, Alice; García-Calvo, Eloy; Gómez, María José; Agüera, Ana; Fernández-Alba, Amadeo R

2010-01-01

This work reports a systematic survey of over seventy individual pollutants in a Sewage Treatment Plant (STP) receiving urban wastewater. The compounds include mainly pharmaceuticals and personal care products, as well as some metabolites. The quantification in the ng/L range was performed by Liquid Chromatography-QTRAP-Mass Spectrometry and Gas Chromatography coupled to Mass Spectrometry. The results showed that paraxanthine, caffeine and acetaminophen were the main individual pollutants usually found in concentrations over 20 ppb. N-formyl-4-amino-antipiryne and galaxolide were also detected in the ppb level. A group of compounds including the beta-blockers atenolol, metoprolol and propanolol; the lipid regulators bezafibrate and fenofibric acid; the antibiotics erythromycin, sulfamethoxazole and trimethoprim, the antiinflammatories diclofenac, indomethacin, ketoprofen and mefenamic acid, the antiepileptic carbamazepine and the antiacid omeprazole exhibited removal efficiencies below 20% in the STP treatment. Ozonation with doses lower than 90 microM allowed the removal of many individual pollutants including some of those more refractory to biological treatment. A kinetic model allowed the determination of second order kinetic constants for the ozonation of bezafibrate, cotinine, diuron and metronidazole. The results show that the hydroxyl radical reaction was the major pathway for the oxidative transformation of these compounds. (c) 2009 Elsevier Ltd. All rights reserved.

Ozone and photocatalytic processes to remove the antibiotic sulfamethoxazole from water.

PubMed

Beltrán, Fernando J; Aguinaco, Almudena; García-Araya, Juan F; Oropesa, Ana

2008-08-01

In this study, water containing the pharmaceutical compound sulfamethoxazole (SMT) was subjected to the various treatments of different oxidation processes involving ozonation, and photolysis and catalysis under different experimental conditions. Removal rates of SMT and total organic carbon (TOC), from experiments of simple UVA radiation, ozonation (O(3)), catalytic ozonation (O(3)/TiO(2)), ozone photolysis (O(3)/UVA), photocatalytic oxidation (O(2)/TiO(2)/UVA) and photocatalytic ozonation (O(3)/UVA/TiO(2)), have been compared. Photocatalytic ozonation leads to the highest SMT removal rate (pH 7 in buffered systems, complete removal is achieved in less than 5min) and total organic carbon (in unbuffered systems, with initial pH=4, 93% TOC removal is reached). Also, lowest ozone consumption per TOC removed and toxicity was achieved with the O(3)/UVA/TiO(2) process. Direct ozone and free radical reactions were found to be the principal mechanisms for SMT and TOC removal, respectively. In photocatalytic ozonation, with buffered (pH 7) aqueous solutions phosphates (buffering salts) and accumulation of bicarbonate scavengers inhibit the reactions completely on the TiO(2) surface. As a consequence, TOC removal diminishes. In all cases, hydrogen peroxide plays a key role in TOC mineralization. According to the results obtained in this work the use of photocatalytic ozonation is recommended to achieve a high mineralization degree of water containing SMT type compounds.

The role of ozone pretreatment on optimization of membrane bioreactor for treatment of oil sands process-affected water.

PubMed

Zhang, Yanyan; Xue, Jinkai; Liu, Yang; Gamal El-Din, Mohamed

2018-04-05

Previously, anoxic-aerobic membrane bioreactor (MBR) coupled with mild ozonation pretreatment has been applied to remove toxic naphthenic acids (NAs) in oil sands process-affected water (OSPW). To further improve MBR performance, the optimal operation conditions including hydraulic retention time (HRT) and initial ammonia nitrogen (NH 4 + -N) need to be explored. In this study, the role of ozone pretreatment on MBR optimization was investigated. Compared with MBR treating raw OSPW, MBR treating ozonated OSPW had the same optimal operation conditions (HRT of 12 h and NH 4 + -N concentration of 25 mg/L). Nevertheless, MBR performance benefited from HRT adjustment more after ozone pretreatment. HRT adjustment resulted in NA removal in the range of 33-50% for the treatment of ozonated OSPW whereas NA removal for raw OSPW only fluctuated between 27% and 38%. Compared with the removal of classical NAs, the degradation of oxidized NAs was more sensitive to the adjustment of operation conditions. Adjusting HRT increased the removal of oxidized NAs in ozonated OSPW substantially (from 6% to 35%). It was also noticed that microbial communities in MBR treating ozonated OSPW were more responsive to the adjustment of operation conditions as indicated by the noticeable increase of Shannon index and extended genetic distances. Copyright © 2018 Elsevier B.V. All rights reserved.

Advanced low carbon-to-nitrogen ratio wastewater treatment by electrochemical and biological coupling process.

PubMed

Deng, Shihai; Li, Desheng; Yang, Xue; Zhu, Shanbin; Xing, Wei

2016-03-01

Nitrogen pollution in ground and surface water significantly affects the environment and its organisms, thereby leading to an increasingly serious environmental problem. Such pollution is difficult to degrade because of the lack of carbon sources. Therefore, an electrochemical and biological coupling process (EBCP) was developed with a composite catalytic biological carrier (CCBC) and applied in a pilot-scale cylindrical reactor to treat wastewater with a carbon-to-nitrogen (C/N) ratio of 2. The startup process, coupling principle, and dynamic feature of the EBCP were examined along with the effects of hydraulic retention time (HRT), dissolved oxygen (DO), and initial pH on nitrogen removal. A stable coupling system was obtained after 51 days when plenty of biofilms were cultivated on the CCBC without inoculation sludge. Autotrophic denitrification, with [Fe(2+)] and [H] produced by iron-carbon galvanic cells in CCBC as electron donors, was confirmed by equity calculation of CODCr and nitrogen removal. Nitrogen removal efficiency was significantly influenced by HRT, DO, and initial pH with optimal values of 3.5 h, 3.5 ± 0.1 mg L(-1), and 7.5 ± 0.1, respectively. The ammonia, nitrate, and total nitrogen (TN) removal efficiencies of 90.1 to 95.3 %, 90.5 to 99.0 %, and 90.3 to 96.5 % were maintained with corresponding initial concentrations of 40 ± 2 mg L(-1) (NH3-N load of 0.27 ± 0.01 kg NH3-N m(-3) d(-1)), 20 ± 1 mg L(-1), and 60 ± 2 mg L(-1) (TN load of 0.41 ± 0.02 kg TN m(-3) d(-1)). Based on the Eckenfelder model, the kinetics equation of the nitrogen transformation along the reactor was N e  = N 0 exp (-0.04368 h/L(1.8438)). Hence, EBCP is a viable method for advanced low C/N ratio wastewater treatment.

The use of ozone, ozone plus UV radiation, and aerobic microorganisms in the purification of some agro-industrial wastewaters.

PubMed

Benitez, F Javier; Acero, Juan L; Gonzalez, Teresa; Garcia, Juan

2002-08-01

The oxidation of the pollutant organic matter present in wastewaters generated during different stages in the black table-olive industry was investigated by using ozone alone or combined with UV radiation; by using aerobic microorganisms; and finally, by aerobic degradation of the previously ozonated wastewaters. In the ozonation processes, the removal of substrate (COD) and aromatic compounds, the decreases in BOD5 and pH, and the ozone consumed in the reaction were evaluated. A kinetic study was conducted that led to the evaluation of the stoichiometric ratio for the chemical reaction, as well as the rate constants for the substrate reduction and ozone disappearance. In the single aerobic degradation treatment, the evolution of substrate and biomass was monitored during the process, and a kinetic study was performed by applying the Contois model to the experimental data, giving the specific biokinetic constant, the cell yield coefficient, and the rate constant for the microorganism death phase. Finally, a combined process was performed, consisting in the aerobic degradation of pre-ozonated wastewaters, and the effect of such chemical pretreatment on the substrate removal and kinetic parameters of the later biological stage is discussed.

The removal of organic precursors of DBPs during three advanced water treatment processes including ultrafiltration, biofiltration, and ozonation.

PubMed

Zha, Xiao-Song; Ma, Lu-Ming; Wu, Jin; Liu, Yan

2016-08-01

The removal efficiency of organic matter, the formation potential of trihalomethanes (THMFP), and the formation potential of haloacetic acids (HAAFP) in each unit of three advanced treatment processes were investigated in this paper. The molecular weight distribution and the components of organic matter in water samples were also determined to study the transformation of organic matter during these advanced treatments. Low-molecular-weight matter was the predominant fraction in raw water, and it could not be removed effectively by ultrafiltration and biofiltration. The dominant species of disinfection by-product formation potential (DBPFP) in raw water were chloroform and monochloroacetic acid (MCAA), with average concentrations of 107.3 and 125.9 μg/L, respectively. However, the formation potential of chloroform and MCAA decreased to 36.2 and 11.5 μg/L after ultrafiltration. Similarly, biological pretreatment obtained high removal efficiency for DBPFP. The total THMFP decreased from 173.8 to 81.8 μg/L, and the total HAAFP decreased from 211.9 to 84.2 μg/L. Separate ozonation had an adverse effect on DBPFP, especially for chlorinated HAAFP. Numerous low-molecular-weight compounds such as aldehydes, ketones, and alcohols were generated during the ozonation, which have been proven to be important precursors of HAAs. However, the ozonation/biological activated carbon (BAC) combined process had a better removal efficiency for DBPFP. The total DBPFP decreased remarkably from 338.7 to 113.3 μg/L after the O3/BAC process, far below the separated BAC of process B (189.1 μg/L).

The Ecophysiology Of A Pinus Ponderosa Ecosystem Exposed To High Tropospheric Ozone: Implications For Stomatal And Non-Stomatal Ozone Fluxes

NASA Astrophysics Data System (ADS)

Fares, S.; McKay, M.; Goldstein, A.

2008-12-01

Ecosystems remove ozone from the troposphere through both stomatal and non-stomatal deposition. The portion of ozone taken up through stomata has an oxidative effect causing damage. We used a multi-year dataset to assess the physiological controls over ozone deposition. Environmental parameters, CO2 and ozone fluxes were measured continuously from January 2001 to December 2006 above a ponderosa pine plantation near Blodgett Forest, Georgetown, California. We studied the dynamic of NEE (Net Ecosystem Exchange, -838 g C m-2 yr-1) and water evapotranspiration on an annual and daily basis. These processes are tightly coupled to stomatal aperture which also controlled ozone fluxes. High levels of ozone concentrations (~ 100 ppb) were observed during the spring-summer period, with corresponding high levels of ozone fluxes (~ 30 μmol m-2 h-1). During the summer season, a large portion of the total ozone flux was due to non-stomatal processes, and we propose that a plant physiological control, releasing BVOC (Biogenic Volatile Organic Compounds), is mainly responsible. We analyzed the correlations of common ozone exposure metrics based on accumulation of concentrations (AOT40 and SUM0) with ozone fluxes (total, stomatal and non-stomatal). Stomatal flux showed poorer correlation with ozone concentrations than non-stomatal flux during summer and fall seasons, which largely corresponded to the growing period. We therefore suggest that AOT40 and SUM0 are poor predictors of ozone damage and that a physiologically based metric would be more effective.

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

PubMed

Nikolov, Ned; Zeller, Karl F

2003-01-01

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

Processes Affecting Tropospheric Ozone over Africa

NASA Technical Reports Server (NTRS)

Diab, Roseanne D.; Thompson, Anne M.

2004-01-01

This is a Workshop Report prepared for Eos, the weekly AGU magazine, The workshop took place between 26-28 January 2004 at the University of KwaZulu-Natal in Durban, South Africa and was attended by 26 participants (http//www.geography.und.ac.za). Considerable progress has been made in ozone observations except for northern Africa (large data gaps) and west Africa (to be covered by the French-sponsored AMMA program). The present-day ozone findings were evaluated and reviewed by speakers using Aircraft data (MOZAIC program), NASA satellites (MOPITT, TRMM, TOMS) and ozone soundings (SHADOZ). Besides some ozone gaps, there are challenges posed by the need to assess the relative strengths of photochemical and dynamic influences on the tropospheric ozone budget. Biogenic, biofuels, biomass burning sources of ozone precursors remain highly uncertain. Recent findings (by NASA's Chatfield and Thompson, using satellite and sounding data) show significant impact of Indian Ocean pollution on African ozone. European research on pollutants over the Mediterranean and the middle east, that suggests that ozone may be exported to Africa from these areas, also needs to be considered.

Combined treatment of mezcal vinasses by ozonation and activated sludge.

PubMed

2017-10-18

In Mexico, mezcal production generates huge amounts of vinasses (MV) that cause negative environmental impacts. Thus, MV treatment is necessary before discharge to water bodies. Although there is no information for mezcal vinasses, similar effluents have been treated by biological processes (i.e. anaerobic and aerobic) usually complemented by oxidative chemical pretreatments (ozonation) and physico-chemical methods. In this work MV were first ozonated and followed by batch aerobic biological degradation. In the ozonation stage, organic matter removals were 4.5-11 % as COD, whereas the removal of aromatic compounds and phenols were 16-32 % and 48-83 % respectively. In the aerobic post-treatment, COD depletions up to 85 % were achieved; removals in ozone pre-treated vinasses were higher (80 to 85 %) than that of raw vinasse (69 %). It seems that ozonation preferentially attacked the recalcitrant fraction of organic matter present in the vinasses and increased its aerobic biodegradability.

Effective utilization of ozone in plasma-based advanced oxidation process

NASA Astrophysics Data System (ADS)

Takeuchi, Nozomi; Ishibashi, Naoto; Sugiyama, Tsuyoshi; Kim, Hyun-Ha

2018-05-01

Decomposition of acetic acid in water was conducted using multiple plasmas generated within oxygen bubbles. Ballast capacitors were used to control the plasma input power, allowing hydrogen peroxide and ozone to be produced at different rates in each plasma by adjusting the capacitance. By using an ozone absorber connected to the plasma reactor, OH radicals, both generated by the plasmas directly and reproduced from hydrogen peroxide through reactions with ozone, could be effectively utilized for the reduction of total organic carbon (TOC). Under the condition with the highest ozone production rate, higher processing speed and energy efficiency for the TOC reduction were achieved compared with other plasma methods.

Application of peroxymonosulfate-ozone advanced oxidation process for simultaneous waste-activated sludge stabilization and dewatering purposes: A comparative study.

PubMed

Badalians Gholikandi, Gagik; Zakizadeh, Nazanin; Masihi, Hamidreza

2018-01-15

In this study, the efficiency of the Peroxymonosulfate-ozone (PMS+O 3 ) advanced oxidation process in lab scale by the aim of stabilization and dewatering the biological excess sludge was investigated and the results were compared with persulfate-ozone (PS+O 3 ), hydrogen peroxide-ozone (H 2 O 2 +O 3 ) and ozonation (O 3 ) processes. The results show that the PMS+O 3 is more effective than other mentioned procedures. Therefore, under optimized conditions (pH = 11, PMS/O 3  = 0.06 and Dose O 3  = 12.5 mmol), VS (Volatile solids) and fecal coliforms reduced respectively 42% and 89% after 60 min and the stabilized sludge in term of pathogen reduction requirements was class B. Furthermore, time to filter (TTF) of sludge decreased 70% relative to the raw sludge. In order to demonstrate the dewatering conditions' improvement, the variations of particle size distribution, extracellular polymeric substances (EPS) and zeta potential were evaluated. Overall, the results show that the PMS+O 3 has the capability of stabilizing and dewatering the sludge simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of natural organic matter treated by iron oxide nanoparticle incorporated ceramic membrane-ozonation process.

PubMed

Park, Hosik; Kim, Yohan; An, Byungryul; Choi, Heechul

2012-11-15

In this study, changes in the physical and structural properties of natural organic matter (NOM) were observed during hybrid ceramic membrane processes that combined ozonation with ultrafiltration ceramic membrane (CM) or with a reactive ceramic membrane (RM), namely, an iron oxide nanoparticles (IONs) incorporated-CM. NOM from feed water and NOM from permeate treated with hybrid ceramic membrane processes were analyzed by employing several NOM characterization techniques. Specific ultraviolet absorbance (SUVA), high-performance size exclusion chromatography (HPSEC) and fractionation analyses showed that the hybrid ceramic membrane process effectively removed and transformed relatively high contents of aromatic, high molecular weight and hydrophobic NOM fractions. Fourier transform infrared spectroscopy (FTIR) and 3-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy revealed that this process caused a significant decrease of the aromaticity of humic-like structures and an increase in electron withdrawing groups. The highest removal efficiency (46%) of hydroxyl radical probe compound (i.e., para-Chlorobenzoic acid (pCBA)) in RM-ozonation process compared with that in CM without ozonation process (8%) revealed the hydroxyl radical formation by the surface-catalyzed reaction between ozone and IONs on the surface of RM. In addition, experimental results on flux decline showed that fouling of RM-ozonation process (15%) was reduced compared with that of CM without ozonation process (30%). These results indicated that the RM-ozonation process enhanced the destruction of NOM and reduced the fouling by generating hydroxyl radicals from the catalytic ozonation in the RM-ozonation process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Issues in Stratospheric Ozone Depletion.

NASA Astrophysics Data System (ADS)

Lloyd, Steven Andrew

Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field

Diagnosing ozone recovery using the O3-N2O relationship

NASA Astrophysics Data System (ADS)

Butler, A. H.; Gao, R. S.; Maycock, A.; Portmann, R. W.; Thornberry, T. D.; Rosenlof, K. H.; Fahey, D. W.

2016-12-01

The ubiquitous compact correlation between collocated values of stratospheric ozone (O3) and the tracer nitrous oxide (N2O) results from the stratospheric photochemical processes that produce ozone and destroy N2O combined with common transport and mixing processes. Changes in the correlation slope under certain circumstances reflect changes in the production and loss balance of ozone. This approach has been used extensively to diagnose and quantify ozone loss in polar spring. Using a coupled atmosphere-ocean model with interactive chemistry (CESM/WACCM), we show that this relationship can be used to diagnose ozone recovery in the lower extratropical stratosphere. We then consider in situ measurements of O3 and N2O from ATTREX, GloPac, and HIPPO as well as satellite measurements from ACE and Aura MLS to consider whether ozone recovery can be detected in observations during the period 2004-2016.

Ozone Sensitivity to Varying Greenhouse Gases and Ozone-Depleting Substances in CCMI-1 Simulations

NASA Technical Reports Server (NTRS)

Morgenstern, Olaf; Stone, Kane A.; Schofield, Robyn; Akiyoshi, Hideharu; Yamashita, Yousuke; Kinnison, Douglas E.; Garcia, Rolando R.; Sudo, Kengo; Plummer, David A.; Scinocca, John;

Ozone sensitivity to varying greenhouse gases and ozone-depleting substances in CCMI-1 simulations

NASA Astrophysics Data System (ADS)

Morgenstern, Olaf; Stone, Kane A.; Schofield, Robyn; Akiyoshi, Hideharu; Yamashita, Yousuke; Kinnison, Douglas E.; Garcia, Rolando R.; Sudo, Kengo; Plummer, David A.; Scinocca, John; Oman, Luke D.; Manyin, Michael E.; Zeng, Guang; Rozanov, Eugene; Stenke, Andrea; Revell, Laura E.; Pitari, Giovanni; Mancini, Eva; Di Genova, Glauco; Visioni, Daniele; Dhomse, Sandip S.; Chipperfield, Martyn P.

2018-01-01

Ozone fields simulated for the first phase of the Chemistry-Climate Model Initiative (CCMI-1) will be used as forcing data in the 6th Coupled Model Intercomparison Project. Here we assess, using reference and sensitivity simulations produced for CCMI-1, the suitability of CCMI-1 model results for this process, investigating the degree of consistency amongst models regarding their responses to variations in individual forcings. We consider the influences of methane, nitrous oxide, a combination of chlorinated or brominated ozone-depleting substances, and a combination of carbon dioxide and other greenhouse gases. We find varying degrees of consistency in the models' responses in ozone to these individual forcings, including some considerable disagreement. In particular, the response of total-column ozone to these forcings is less consistent across the multi-model ensemble than profile comparisons. We analyse how stratospheric age of air, a commonly used diagnostic of stratospheric transport, responds to the forcings. For this diagnostic we find some salient differences in model behaviour, which may explain some of the findings for ozone. The findings imply that the ozone fields derived from CCMI-1 are subject to considerable uncertainties regarding the impacts of these anthropogenic forcings. We offer some thoughts on how to best approach the problem of generating a consensus ozone database from a multi-model ensemble such as CCMI-1.

Intense Electrochemical Oxidation on Graphitized Carbon Electrodes in the Presence of Ozone

NASA Astrophysics Data System (ADS)

Klochikhin, V. L.; Potapova, G. F.; Putilov, A. V.

2018-06-01

A new intense oxidation process for water treatment in which oxidation with ozone is coupled to electrochemical processes is described, and the results from its application to water purification are presented along with the discussion of its practical implementation. The use of graphitized carbon materials for this process is explained and tested experimentally. The use of glassy carbon for the anode enables us to achieve very high (up to 25 vol %) concentrations of ozone in the generated ozone-oxygen mixture. The material used for the cathode—graphitized carbon cloth (GCC) reinforced with Ni allows different electrocatalytic processes to proceed on its developed surface, and combines the high sorption capacity of this cathode and potentialcontrolled selectivity of cathodic electrochemical processes.

Stratospheric ozone depletion

PubMed Central

Rowland, F. Sherwood

2006-01-01

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

Sensitivity of volatile organic compounds (VOCs) and ozone to land surface processes and vegetation distributions in California

NASA Astrophysics Data System (ADS)

Zhao, C.; Huang, M.; Fast, J. D.; Berg, L. K.; Qian, Y.; Guenther, A. B.; Gu, D.; Shrivastava, M. B.; Liu, Y.; Walters, S.; Jin, J.

2014-12-01

Current climate models still have large uncertainties in estimating biogenic trace gases, which can significantly affect secondary organic aerosol (SOA) formation and ultimately aerosol radiative forcing. These uncertainties result from many factors, including coupling strategy between biogenic emissions and land-surface schemes and specification of vegetation types, both of which can affect the simulated near-surface fluxes of biogenic volatile organic compounds (VOCs). In this study, sensitivity experiments are conducted using the Weather Research and Forecasting model with chemistry (WRF-Chem) to examine the sensitivity of simulated VOCs and ozone to land surface processes and vegetation distributions in California. The measurements collected during the California Nexus of Air Quality and Climate Experiment (CalNex) and the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted during May and June of 2010 provide a good opportunity to evaluate the simulations. First, the biogenic VOC emissions in the WRF-Chem simulations with the two land surface schemes, Noah and CLM4, are estimated by the Model of Emissions of Gases and Aerosols from Nature version one (MEGANv1), which has been publicly released and widely used with WRF-Chem. The impacts of land surface processes on estimating biogenic VOC emissions and simulating VOCs and ozone are investigated. Second, in this study, a newer version of MEGAN (MEGANv2.1) is coupled with CLM4 as part of WRF-Chem to examine the sensitivity of biogenic VOC emissions to the MEGAN schemes used and determine the importance of using a consistent vegetation map between a land surface scheme and the biogenic VOC emission scheme. Specifically, MEGANv2.1 is embedded into the CLM4 scheme and shares a consistent vegetation map for estimating biogenic VOC emissions. This is unlike MEGANv1 in WRF-Chem that uses a standalone vegetation map that differs from what is used in land surface schemes. Furthermore, we examine the impact

Granular activated carbon promoted ozonation of a food-processing secondary effluent.

PubMed

Alvarez, Pedro M; Pocostales, J Pablo; Beltrán, Fernando J

2011-01-30

This paper reports on the application of a simultaneous combination of ozone and a granular activated carbon (O(3)/GAC) as a tertiary treatment of a wastewater generated from the activity of various food-processing industries. Prior to the O(3)/GAC treatment, the wastewater was subjected to conventional primary and secondary treatments in a full-scale wastewater treatment plant (WWTP). The effluent from the WWTP presented high organic load (COD>500 mg/l and TOC>150 mg/l), which could be much reduced by the O(3)/GAC treatment. Results from the O(3)/GAC experiments were compared with those obtained in single ozonation, single adsorption onto GAC and sequential O(3)-GAC adsorption experiments. While single processes and the sequential one showed limited capacity to remove organic matter for the food-processing effluent (COD removal <40%), the simultaneous O(3)/GAC process led to decreases of COD up to 82% at the conditions here applied. The combined process also improved the ozone consumption, which decreased from about 19 g O(3)/g TOC (single ozonation process) to 8.2-10.7 g O(3)/g TOC (O(3)/GAC process). The reusability of the GAC throughout a series of consecutive O(3)/GAC experiments was studied with no apparent loss of activity for a neutral GAC (PZC = 6.7) but for a basic GAC (PZC = 9.1). Copyright © 2010 Elsevier B.V. All rights reserved.

Low temperature ozone oxidation of solid waste surrogates

NASA Astrophysics Data System (ADS)

Nabity, James A.; Lee, Jeffrey M.

2015-09-01

Solid waste management presents a significant challenge to human spaceflight and especially, long-term missions beyond Earth orbit. A six-month mission will generate over 300 kg of solid wastes per crewmember that must be dealt with to eliminate the need for storage and prevent it from becoming a biological hazard to the crew. There are several methods for the treatment of wastes that include oxidation via ozone, incineration, microbial oxidation or pyrolysis and physical methods such as microwave drying and compaction. In recent years, a low temperature oxidation process using ozonated water has been developed for the chemical conversion of organic wastes to CO2 and H2O. Experiments were conducted to evaluate the rate and effectiveness with which ozone oxidized several different waste materials. Increasing the surface area by chopping or shredding the solids into small pieces more than doubled the rate of oxidation. A greater flow of ozone and agitation of the ozonated water system also increased processing rates. Of the materials investigated, plastics have proven the most difficult to oxidize. The processing of plastics above the glass transition temperatures caused the plastics to clump together which reduced the exposed surface area, while processing at lower temperatures reduced surface reaction kinetics.

Elimination of Two Hormones by Ultrasonic and Ozone Combined Processes

NASA Astrophysics Data System (ADS)

Mingcan Cui,; Younggyu Son,; Myunghee Lim,; Seungmin Na,; Jeehyeong Khim,

2010-07-01

A direct ultrasonic (US) and ozone (O3) combination (US/O3) process for the removal of two hormones, estrone (E1) and estriol (E3), in aqueous solutions was investigated. These two hormones were detected in a wastewater treatment plant effluent in Korea. It was found that the ultrasonic/ozone process showed a higher removal performance than the US and O3 process even though the O3 process also showed approximately the same removal efficiency after 60 min. Chemical oxygen demand/total organic carbon (CODcr/TOC) ratios for E1 and E3 decreased, indicating that biodegradability could be increased significantly in the US/O3 process. The optimal pH condition was determined above the neutral pH condition.

On ozone trend detection: using coupled chemistry-climate simulations to investigate early signs of total column ozone recovery

NASA Astrophysics Data System (ADS)

Keeble, James; Brown, Hannah; Abraham, N. Luke; Harris, Neil R. P.; Pyle, John A.

2018-06-01

Total column ozone values from an ensemble of UM-UKCA model simulations are examined to investigate different definitions of progress on the road to ozone recovery. The impacts of modelled internal atmospheric variability are accounted for by applying a multiple linear regression model to modelled total column ozone values, and ozone trend analysis is performed on the resulting ozone residuals. Three definitions of recovery are investigated: (i) a slowed rate of decline and the date of minimum column ozone, (ii) the identification of significant positive trends and (iii) a return to historic values. A return to past thresholds is the last state to be achieved. Minimum column ozone values, averaged from 60° S to 60° N, occur between 1990 and 1995 for each ensemble member, driven in part by the solar minimum conditions during the 1990s. When natural cycles are accounted for, identification of the year of minimum ozone in the resulting ozone residuals is uncertain, with minimum values for each ensemble member occurring at different times between 1992 and 2000. As a result of this large variability, identification of the date of minimum ozone constitutes a poor measure of ozone recovery. Trends for the 2000-2017 period are positive at most latitudes and are statistically significant in the mid-latitudes in both hemispheres when natural cycles are accounted for. This significance results largely from the large sample size of the multi-member ensemble. Significant trends cannot be identified by 2017 at the highest latitudes, due to the large interannual variability in the data, nor in the tropics, due to the small trend magnitude, although it is projected that significant trends may be identified in these regions soon thereafter. While significant positive trends in total column ozone could be identified at all latitudes by ˜ 2030, column ozone values which are lower than the 1980 annual mean can occur in the mid-latitudes until ˜ 2050, and in the tropics and high

Ozone from fireworks: Chemical processes or measurement interference?

PubMed

Xu, Zheng; Nie, Wei; Chi, Xuguang; Huang, Xin; Zheng, Longfei; Xu, Zhengning; Wang, Jiaping; Xie, Yuning; Qi, Ximeng; Wang, Xinfeng; Xue, Likun; Ding, Aijun

2018-08-15

Fireworks have been identified as one ozone source by photolyzing NO 2 or O 2 and are believed to potentially be important for the nighttime ozone during firework events. In this study, we conducted both lab and field experiments to test two types of fireworks with low and high energy with the goal to distinguish whether the visible ozone signal during firework displays is real. The results suggest that previous understanding of the ozone formation mechanism during fireworks is misunderstood. Ultraviolet ray (UV)-based ozone monitors are interfered by aerosols and some specific VOCs. High-energy fireworks emit high concentrations of particular matters and low VOCs that the artificial ozone can be easily removed by an aerosol filter. Low-energy fireworks emit large amounts of VOCs mostly from the combustion of the cardboard from fireworks that largely interferes with the ozone monitor. Benzene and phenol might be major contributors to the artificial ozone signal. We further checked the nighttime ozone concentration in Jinan and Beijing, China, during Chinese New Year, a period with intense fireworks. A signal of 3-8ppbv ozone was detected and positively correlated to NO and SO 2 , suggesting a considerable influence of these chemicals in interfering with ambient ozone monitoring. Copyright © 2018 Elsevier B.V. All rights reserved.

Coupling Processes between Atmospheric Chemistry and Climate

NASA Technical Reports Server (NTRS)

Ko, Malcolm K. W.; Weisenstein, Debra K.; Shia, Run-Lie; Scott, Courtney J.; Sze, Nien Dak

1998-01-01

This is the fourth semi-annual report for NAS5-97039, covering the time period July through December 1998. The overall objective of this project is to improve the understanding of coupling processes between atmospheric chemistry and climate. Model predictions of the future distributions of trace gases in the atmosphere constitute an important component of the input necessary for quantitative assessments of global change. We will concentrate on the changes in ozone and stratospheric sulfate aerosol, with emphasis on how ozone in the lower stratosphere would respond to natural or anthropogenic changes. The key modeling tools for this work are the Atmospheric and Environmental Research (AER) two-dimensional chemistry-transport model, the AER two-dimensional stratospheric sulfate model, and the AER three-wave interactive model with full chemistry. For this six month period, we report on a modeling study of new rate constant which modify the NOx/NOy ratio in the lower stratosphere; sensitivity to changes in stratospheric water vapor in the future atmosphere; a study of N2O and CH4 observations which has allowed us to adjust diffusion in the 2-D CTM in order to obtain appropriate polar vortex isolation; a study of SF6 and age of air with comparisons of models and measurements; and a report on the Models and Measurements II effort.

Effective organics degradation from pharmaceutical wastewater by an integrated process including membrane bioreactor and ozonation.

PubMed

Mascolo, G; Laera, G; Pollice, A; Cassano, D; Pinto, A; Salerno, C; Lopez, A

2010-02-01

The enhanced removal of organic compounds from a pharmaceutical wastewater resulting from the production of an anti-viral drug (acyclovir) was obtained by employing a membrane bioreactor (MBR) and an ozonation system. An integrated MBR-ozonation system was set-up by placing the ozonation reactor in the recirculation stream of the MBR effluent. A conventional treatment set-up (ozonation as polishing step after MBR) was also used as a reference. The biological treatment alone reached an average COD removal of 99%, which remained unvaried when the ozonation step was introduced. An acyclovir removal of 99% was also obtained with the MBR step and the ozonation allowed to further remove 99% of the residual concentration in the MBR effluent. For several of the 28 organics identified in the wastewater the efficiency of the MBR treatment improved from 20% to 60% as soon as the ozonation was placed in the recirculation stream. The benefit of the integrated system, with respect to the conventional treatment set-up was evident for the removal of a specific ozonation by-product. The latter was efficiently removed in the integrated system, being its abundance in the final effluent 20-fold lower than what obtained when ozonation was used as a polishing step. In addition, if the conventional treatment configuration is employed, the same performance of the integrated system in terms of by-product removal can only be obtained when the ozonation is operated for longer than 60 min. This demonstrates the effectiveness of the integrated system compared to the conventional polishing configuration. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

HYDROXYL RADICAL/OZONE RATIOS DURING OZONATION PROCESSES. I. THE RCT CONCEPT

EPA Science Inventory

The ozonation of model systems and several natural waters was examined in bench-scale batch experiments. In addition to measuring the concentration of ozone (03), the rate of depletion of an in situ hydroxyl radical probe compound was monitored, thus providing information on the ...

Comparison of methylisoborneol and geosmin abatement in surface water by conventional ozonation and an electro-peroxone process.

PubMed

Yao, Weikun; Qu, Qiangyong; von Gunten, Urs; Chen, Chao; Yu, Gang; Wang, Yujue

2017-01-01

In this study methylisoborneol (MIB) and geosmin abatement in a surface water by conventional ozonation and the electro-peroxone (E-peroxone) process was compared. Batch tests with addition of ozone (O 3 ) stock solutions and semi-batch tests with continuous O 2 /O 3 gas sparging (simulating real ozone contactors) were conducted to investigate O 3 decomposition, •OH production, MIB and geosmin abatement, and bromate formation during the two processes. Results show that with specific ozone doses typically used in routine drinking water treatment (0.5-1.0 mg O 3 /mg dissolved organic carbon (DOC)), conventional ozonation could not adequately abate MIB and geosmin in a surface water. While increasing the specific ozone doses (1.0-2.5 mg O 3 /mg DOC) could enhance MIB and geosmin abatement by conventional ozonation, this approach resulted in significant bromate formation. By installing a carbon-based cathode to electrochemically produce H 2 O 2 from cathodic oxygen reduction, conventional ozonation can be conveniently upgraded to an E-peroxone process. The electro-generated H 2 O 2 considerably enhanced the kinetics and to a lesser extent the yields of hydroxyl radical (•OH) from O 3 decomposition. Consequently, during the E-peroxone process, abatement of MIB and geosmin occurred at much higher rates than during conventional ozonation. In addition, for a given specific ozone dose, the MIB and geosmin abatement efficiencies increased moderately in the E-peroxone (by ∼8-9% and ∼10-25% in the batch and semi-batch tests, respectively) with significantly lower bromate formation compared to conventional ozonation. These results suggest that the E-peroxone process may serve as an attractive backup of conventional ozonation processes during accidental spills or seasonal events such as algal blooms when high ozone doses are required to enhance MIB and geosmin abatement. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of slaughter wastewater by coagulation sedimentation-anaerobic biological filter and biological contact oxidation process

NASA Astrophysics Data System (ADS)

Sun, M.; Yu, P. F.; Fu, J. X.; Ji, X. Q.; Jiang, T.

2017-08-01

The optimal process parameters and conditions for the treatment of slaughterhouse wastewater by coagulation sedimentation-AF - biological contact oxidation process were studied to solve the problem of high concentration organic wastewater treatment in the production of small and medium sized slaughter plants. The suitable water temperature and the optimum reaction time are determined by the experiment of precipitation to study the effect of filtration rate and reflux ratio on COD and SS in anaerobic biological filter and the effect of biofilm thickness and gas water ratio on NH3-N and COD in biological contact oxidation tank, and results show that the optimum temperature is 16-24°C, reaction time is 20 min in coagulating sedimentation, the optimum filtration rate is 0.6 m/h, and the optimum reflux ratio is 300% in anaerobic biological filter reactor. The most suitable biological film thickness range of 1.8-2.2 mm and the most suitable gas water ratio is 12:1-14:1 in biological contact oxidation pool. In the coupling process of continuous operation for 80 days, the average effluent’s mass concentrations of COD, TP and TN were 15.57 mg/L, 40 mg/L and 0.63 mg/L, the average removal rates were 98.93%, 86.10%, 88.95%, respectively. The coupling process has stable operation effect and good effluent quality, and is suitable for the industrial application.

Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats.

EPA Science Inventory

SOT2014 Abstract for presentation: March 23-27, 2014; Phoenix, AZ Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats. V. Bass, D. Andrews, J. Richards, M. Schladweiler, A. Ledb...

Making equipment to process paddy water for providing drinking water by using Ozone-UVC& Ultrafiltration

NASA Astrophysics Data System (ADS)

Styani, E.; Dja'var, N.; Irawan, C.; Hanafi

2018-01-01

This study focuses on making equipment which is useful to process paddy water to be consumable as drinking water by using ozone-UVC and ultrafiltration. The equipment which is made by the process of ozone-UVC and ultrafiltration or reverse osmosis is driven by electric power generated from solar panels. In the experiment, reverse osmosis system with ozone-UVC reactor proves to be good enough in producing high quality drinking water.

Polar ozone

NASA Technical Reports Server (NTRS)

Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

1990-01-01

The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

Oil refinery wastewater treatment using coupled electrocoagulation and fixed film biological processes

NASA Astrophysics Data System (ADS)

Pérez, Laura S.; Rodriguez, Oscar M.; Reyna, Silvia; Sánchez-Salas, José Luis; Lozada, J. Daniel; Quiroz, Marco A.; Bandala, Erick R.

2016-02-01

Oil refinery wastewater was treated using a coupled treatment process including electrocoagulation (EC) and a fixed film aerobic bioreactor. Different variables were tested to identify the best conditions using this procedure. After EC, the effluent was treated in an aerobic biofilter. EC was capable to remove over 88% of the overall chemical oxygen demand (COD) in the wastewater under the best working conditions (6.5 V, 0.1 M NaCl, 4 electrodes without initial pH adjustment) with total petroleum hydrocarbon (TPH) removal slightly higher than 80%. Aluminum release from the electrodes to the wastewater was found an important factor for the EC efficiency and closely related with several operational factors. Application of EC allowed to increase the biodegradability of the sample from 0.015, rated as non-biodegradable, up to 0.5 widely considered as biodegradable. The effluent was further treated using an aerobic biofilter inoculated with a bacterial consortium including gram positive and gram negative strains and tested for COD and TPH removal from the EC treated effluent during 30 days. Cell count showed the typical bacteria growth starting at day three and increasing up to a maximum after eight days. After day eight, cell growth showed a plateau which agreed with the highest decrease on contaminant concentration. Final TPHs concentration was found about 600 mgL-1 after 30 days whereas COD concentration after biological treatment was as low as 933 mgL-1. The coupled EC-aerobic biofilter was capable to remove up to 98% of the total TPH amount and over 95% of the COD load in the oil refinery wastewater.

Interconnection of reactive oxygen species chemistry across the interfaces of atmospheric, environmental, and biological processes.

PubMed

Anglada, Josep M; Martins-Costa, Marilia; Francisco, Joseph S; Ruiz-López, Manuel F

2015-03-17

Oxidation reactions are ubiquitous and play key roles in the chemistry of the atmosphere, in water treatment processes, and in aerobic organisms. Ozone (O3), hydrogen peroxide (H2O2), hydrogen polyoxides (H2Ox, x > 2), associated hydroxyl and hydroperoxyl radicals (HOx = OH and HO2), and superoxide and ozonide anions (O2(-) and O3(-), respectively) are the primary oxidants in these systems. They are commonly classified as reactive oxygen species (ROS). Atmospheric chemistry is driven by a complex system of chain reactions of species, including nitrogen oxides, hydroxyl and hydroperoxide radicals, alkoxy and peroxy radicals, and ozone. HOx radicals contribute to keeping air clean, but in polluted areas, the ozone concentration increases and creates a negative impact on plants and animals. Indeed, ozone concentration is used to assess air quality worldwide. Clouds have a direct effect on the chemical composition of the atmosphere. On one hand, cloud droplets absorb many trace atmospheric gases, which can be scavenged by rain and fog. On the other hand, ionic species can form in this medium, which makes the chemistry of the atmosphere richer and more complex. Furthermore, recent studies have suggested that air-cloud interfaces might have a significant impact on the overall chemistry of the troposphere. Despite the large differences in molecular composition, concentration, and thermodynamic conditions among atmospheric, environmental, and biological systems, the underlying chemistry involving ROS has many similarities. In this Account, we examine ROS and discuss the chemical characteristics common to all of these systems. In water treatment, ROS are key components of an important subset of advanced oxidation processes. Ozonation, peroxone chemistry, and Fenton reactions play important roles in generating sufficient amounts of hydroxyl radicals to purify wastewater. Biochemical processes within living organisms also involve ROS. These species can come from pollutants in

Plasmachemical and heterogeneous processes in ozonizers with oxygen activation by a dielectric barrier discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mankelevich, Yu. A., E-mail: ymankelevich@mics.msu.su; Voronina, E. N.; Poroykov, A. Yu.

Plasmachemical and heterogeneous processes of generation and loss of ozone in the atmosphericpressure dielectric barrier discharge in oxygen are studied theoretically. Plasmachemical and electronic kinetics in the stage of development and decay of a single plasma filament (microdischarge) are calculated numerically with and without allowance for the effects of ozone vibrational excitation and high initial ozone concentration. The developed analytical approach is applied to determine the output ozone concentration taking into account ozone heterogeneous losses on the Al{sub 2}O{sub 3} dielectric surface. Using the results of quantummechanical calculations by the method of density functional theory, a multistage catalytic mechanism ofmore » heterogeneous ozone loss based on the initial passivation of a pure Al{sub 2}O{sub 3} surface by ozone and the subsequent interaction of O{sub 3} molecules with the passivated surface is proposed. It is shown that the conversion reaction 2O{sub 3} → 3O{sub 2} of a gas-phase ozone molecule with a physically adsorbed ozone molecule can result in the saturation of the maximum achievable ozone concentration at high specific energy depositions, the nonstationarity of the output ozone concentration, and its dependence on the prehistory of ozonizer operation.« less

Biodegradability of DBP precursors after drinking water ozonation.

PubMed

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

2016-12-01

Ozonation is known to generate biodegradable organic matter, which is typically reduced by biological filtration to avoid bacterial regrowth in distribution systems. Post-chlorination generates halogenated disinfection byproducts (DBPs) but little is known about the biodegradability of their precursors. This study determined the effect of ozonation and biofiltration conditions, specifically ozone exposure and empty bed contact time (EBCT), on the control of DBP formation potentials in drinking water. Ozone exposure was varied through addition of H 2 O 2 during ozonation at 1 mgO 3 /mgDOC followed by biological filtration using either activated carbon (BAC) or anthracite. Ozonation led to a 10% decrease in dissolved organic carbon (DOC), without further improvement from H 2 O 2 addition. Raising H 2 O 2 concentrations from 0 to 2 mmol/mmolO 3 resulted in increased DBP formation potentials during post-chlorination of the ozonated water (target Cl 2 residual after 24 h = 1-2 mg/L) as follows: 4 trihalomethanes (THM4, 37%), 8 haloacetic acids (HAA8, 44%), chloral hydrate (CH, 107%), 2 haloketones (HK2, 97%), 4 haloacetonitriles (HAN4, 33%), trichloroacetamide (TCAM, 43%), and adsorbable organic halogen (AOX, 27%), but a decrease in the concentrations of 2 trihalonitromethanes (THNM2, 43%). Coupling ozonation with biofiltration prior to chlorination effectively lowered the formation potentials of all DBPs including CH, HK2, and THNM2, all of which increased after ozonation. The dynamics of DBP formation potentials during BAC filtration at different EBCTs followed first-order reaction kinetics. Minimum steady-state concentrations were attained at an EBCT of about 10-20 min, depending on the DBP species. The rate of reduction in DBP formation potentials varied among individual species before reaching their minimum concentrations. CH, HK2, and THNM2 had the highest rate constants of between 0.5 and 0.6 min -1 followed by HAN4 (0.4 min -1 ), THM4 (0.3 min -1 ), HAA8 (0

Ozone generation by negative corona discharge: the effect of Joule heating

NASA Astrophysics Data System (ADS)

Yanallah, K.; Pontiga, F.; Fernández-Rueda, A.; Castellanos, A.; Belasri, A.

2008-10-01

Ozone generation in pure oxygen using a wire-to-cylinder corona discharge reactor is experimentally and numerically investigated. Ozone concentration is determined by means of direct UV spectroscopy and the effects of Joule heating and ozone decomposition on the electrodes are analysed for different discharge gaps. The numerical model combines the physical processes in the corona discharge with the chemistry of ozone formation and destruction. The chemical kinetics model and the electrical model are coupled through Poisson's equation, and the current-voltage (CV) characteristic measured in experiments is used as input data to the numerical simulation. The numerical model is able to predict the radial distributions of electrons, ions, atoms and molecules for each applied voltage of the CV characteristic. In particular, the evolution of ozone density inside the discharge cell has been investigated as a function of current intensity and applied voltage.

Impact of downward-mixing ozone on surface ozone accumulation in southern Taiwan.

PubMed

Lin, Ching-Ho

2008-04-01

The ozone that initially presents in the previous day's afternoon mixing layer can remain in the nighttime atmosphere and then be carried over to the next morning. Finally, this ozone can be brought to the ground by downward mixing as mixing depth increases during the daytime, thereby increasing surface ozone concentrations. Variation of ozone concentration during each of these periods is investigated in this work. First, ozone concentrations existing in the daily early morning atmosphere at the altitude range of the daily maximum mixing depth (residual ozone concentrations) were measured using tethered ozonesondes on 52 experimental days during 2004-2005 in southern Taiwan. Daily downward-mixing ozone concentrations were calculated by a box model coupling the measured daily residual ozone concentrations and daily mixing depth variations. The ozone concentrations upwind in the previous day's afternoon mixing layer were estimated by the combination of back air trajectory analysis and known previous day's surface ozone distributions. Additionally, the relationship between daily downward-mixing ozone concentration and daily photochemically produced ozone concentration was examined. The latter was calculated by removing the former from daily surface maximum ozone concentration. The measured daily residual ozone concentrations distributed at 12-74 parts per billion (ppb) with an average of 42 +/- 17 ppb are well correlated with the previous upwind ozone concentration (R2 = 0.54-0.65). Approximately 60% of the previous upwind ozone was estimated to be carried over to the next morning and became the observed residual ozone. The daily downward-mixing ozone contributes 48 +/- 18% of the daily surface maximum ozone concentration, indicating that the downward-mixing ozone is as important as daily photochemically produced ozone to daily surface maximum ozone accumulation. The daily downward-mixing ozone is poorly correlated with the daily photochemically produced ozone and

Assessment of Fenton's reagent and ozonation as pre-treatments for increasing the biodegradability of aqueous diethanolamine solutions from an oil refinery gas sweetening process.

PubMed

Durán-Moreno, A; García-González, S A; Gutiérrez-Lara, M R; Rigas, F; Ramírez-Zamora, R M

2011-02-28

The aim of this work was to evaluate the efficiency of three chemical oxidation processes for increasing the biodegradability of aqueous diethanolamine solutions (aqueous DEA solutions), to be used as pre-treatments before a biological process. The raw aqueous DEA solution, sourced from a sour gas sweetening plant at a Mexican oil refinery, was first characterized by standardized physico-chemical methods. Then experiments were conducted on diluted aqueous DEA solutions to test the effects of Fenton's reagent, ozone and ozone-hydrogen peroxide on the removal of some physicochemical parameters of these solutions. Lastly, biodegradability tests based on Dissolved Organic Carbon Die Away OECD301-A, were carried out on a dilution of the raw aqueous DEA solution and on the treated aqueous DEA solutions, produced by applying the best experimental conditions determined during the aforementioned oxidation tests. Experimental results showed that for aqueous DEA solutions treated with Fenton's reagent, the best degradation rate (70%) was obtained at pH 2.8, with Fe(2+) and H(2)O(2) at doses of 1000 and 10,000 mg/L respectively. In the ozone process, the best degradation (60%) was observed in aqueous DEA solution (100 mg COD/L), using 100 mg O(3)/L at pH 5. In the ozone-hydrogen peroxide process, no COD or DOC removals were observed. The diluted spent diethanolamine solution showed its greatest increase in biodegradability after a reaction period of 28 days when treated with Fenton's reagent, but after only 15 days in the case of ozonation. Copyright © 2011 Elsevier B.V. All rights reserved.

Oxidative stress responses of Daphnia magna exposed to effluents spiked with emerging contaminants under ozonation and advanced oxidation processes.

PubMed

Oropesa, Ana Lourdes; Novais, Sara C; Lemos, Marco F L; Espejo, Azahara; Gravato, Carlos; Beltrán, Fernando

2017-01-01

Integration of conventional wastewater treatments with advanced oxidation processes (AOPs) has become of great interest to remove pharmaceuticals and their metabolites from wastewater. However, application of these technologies generates reactive oxygen species (ROS) that may reach superficial waters through effluents from sewage treatment plants. The main objective of the present study was to elucidate if ROS present in real effluents after biological and then chemical (single ozonation, solar photolytic ozonation, solar photocatalytic ozonation (TiO 2 , Fe 3 O 4 ) and solar photocatalytic oxidation (TiO 2 )) treatments induce oxidative stress in Daphnia magna. For this, the activity of two antioxidant enzymes (superoxide dismutase and catalase) and the level of lipid peroxidation were determined in Daphnia. The results of oxidative stress biomarkers studied suggest that D. magna is able to cope with the superoxide ion radical (O 2 · - ) present in the treated effluent due to single ozonation by mainly inducing the antioxidant activity superoxide dismutase, thus preventing lipid peroxidation. Lethal effects (measured in terms of immobility) were not observed in these organisms after exposure to any solution. Therefore, in order to probe the ecological efficiency of urban wastewater treatments, studies on lethal and sublethal effects in D. magna would be advisable.

Understanding the biological underpinnings of ecohydrological processes

NASA Astrophysics Data System (ADS)

Huxman, T. E.; Scott, R. L.; Barron-Gafford, G. A.; Hamerlynck, E. P.; Jenerette, D.; Tissue, D. T.; Breshears, D. D.; Saleska, S. R.

2012-12-01

Climate change presents a challenge for predicting ecosystem response, as multiple factors drive both the physical and life processes happening on the land surface and their interactions result in a complex, evolving coupled system. For example, changes in surface temperature and precipitation influence near-surface hydrology through impacts on system energy balance, affecting a range of physical processes. These changes in the salient features of the environment affect biological processes and elicit responses along the hierarchy of life (biochemistry to community composition). Many of these structural or process changes can alter patterns of soil water-use and influence land surface characteristics that affect local climate. Of the many features that affect our ability to predict the future dynamics of ecosystems, it is this hierarchical response of life that creates substantial complexity. Advances in the ability to predict or understand aspects of demography help describe thresholds in coupled ecohydrological system. Disentangling the physical and biological features that underlie land surface dynamics following disturbance are allowing a better understanding of the partitioning of water in the time-course of recovery. Better predicting the timing of phenology and key seasonal events allow for a more accurate description of the full functional response of the land surface to climate. In addition, explicitly considering the hierarchical structural features of life are helping to describe complex time-dependent behavior in ecosystems. However, despite this progress, we have yet to build an ability to fully account for the generalization of the main features of living systems into models that can describe ecohydrological processes, especially acclimation, assembly and adaptation. This is unfortunate, given that many key ecosystem services are functions of these coupled co-evolutionary processes. To date, both the lack of controlled measurements and experimentation

Degradation of methylparaben in water by corona plasma coupled with ozonation.

PubMed

Dobrin, D; Magureanu, M; Bradu, C; Mandache, N B; Ionita, P; Parvulescu, V I

2014-11-01

The degradation of methylparaben (MeP) in water was investigated using a pulsed corona discharge generated in oxygen, above the liquid. A comparison was made between results obtained in semi-batch corona (SBC) configuration (stationary solution, continuous gas flow) and results obtained in a semi-batch corona with recirculation combined with ozonation (SBCR + O3), where the liquid is continuously circulated between a solution reservoir and the plasma reactor and the effluent gas containing ozone is bubbled through the solution in the reservoir. It was found that MeP was completely degraded after 10-15 min of treatment in both configurations. Oxidation by ozone alone, in the absence of plasma, was a slower process. The energy efficiency for MeP removal (Y MeP) and for mineralization (Y TOC) was significantly higher in the SBCR + O3 configuration (Y MeP = 7.1 g/kWh at 90 % MeP removal and Y TOC = 0.41 g/kWh at 50 % total organic carbon (TOC) removal) than in the SBC configuration (Y MeP = 0.6 g/kWh at 90 % MeP removal and Y TOC = 0.11 g/kWh at 50 % TOC removal).

Nonlocal thermodynamic equilibrium processes in ozone - Implications for the energy budget of the mesosphere and lower thermosphere

NASA Technical Reports Server (NTRS)

Milynczak, Martin G.

1991-01-01

The conversion of chemical potential energy and infrared radiative energy to kinetic energy by non-LTE processes involving ozone is a potentially significant source of heat in the terrestrial upper mesosphere and lower thermosphere. Heating rates are calculated and compared using two different statistical equilibrium models previously applied in the analysis of measurements of limb emission from ozone. The calculated heating depends strongly on the assumed distribution and relaxation of energy in the quasi-nascent ozone molecule. Finally, in the absence of a detailed data base of rate coefficients it may be possible to estimate the heating rate due to non-LTE processes in ozone from appropriate satellite measurements of the ozone concentration and of the infrared emission from ozone in the 9-12 micron spectral interval.

Effects of a modular two-step ozone-water and annealing process on silicon carbide graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, Matthew J., E-mail: matthew.webb@cantab.net; Lundstedt, Anna; Grennberg, Helena

By combining ozone and water, the effect of exposing epitaxial graphene on silicon carbide to an aggressive wet-chemical process has been evaluated after high temperature annealing in ultra high vacuum. The decomposition of ozone in water produces a number of oxidizing species, however, despite long exposure times to the aqueous-ozone environment, no graphene oxide was observed after the two-step process. The systems were comprehensively characterized before and after processing using Raman spectroscopy, core level photoemission spectroscopy, and angle resolved photoemission spectroscopy together with low energy electron diffraction, low energy electron microscopy, and atomic force microscopy. In spite of the chemicalmore » potential of the aqueous-ozone reaction environment, the graphene domains were largely unaffected raising the prospect of employing such simple chemical and annealing protocols to clean or prepare epitaxial graphene surfaces.« less

An investigation of the processes controlling ozone in the upper stratosphere

NASA Technical Reports Server (NTRS)

Patten, Kenneth O., Jr.; Connell, Peter S.; Kinnison, Douglas E.; Wuebbles, Donald J.; Waters, Joe; Froidevaux, Lucien; Slanger, Tom G.

1994-01-01

Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory 2-D zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based upon recent information on vibrational distributions of excited oxygen and upon preliminary studies of energy transfer from the excited oxygen. When the energy transfer rate constants of previous work are assumed, increases in model ozone concentrations of up to 40 percent in the upper stratosphere are found, and the ozone concentrations of the model agree with measurements, including data from the Upper Atmosphere Research Satellite. However, the increase is about 0.4 percent when the larger energy transfer rate constants suggested by more recent experimental work are applied in the model. This indicates the importance of obtaining detailed information on vibrationally excited oxygen properties to evaluation of this process for stratospheric modelling.

Ozone as a laundry agent on orbit and on the ground

NASA Technical Reports Server (NTRS)

Agosto, William N.

1994-01-01

Ozone (03), is the strongest commercial oxidizing agent for aqueous systems and may be ideal for space station laundering operations. It can be generated electronically from air in situ. It kills virtually all microorganisms, attacks many organics and inorganics, and breaks down stable ring structures of benzene and related oils when coupled with ultra violet radiation. It cleans and disinfects in cold water without the need for detergent. It leaves no residues. Ozone permits up to 90% wash water recycling and it eliminates wash time, water volume, and recycling problems of a detergent rinse. Ozone is self purging and converts spontaneously to oxygen. It can be rapidly purged by well established catalytic and thermal processes. Scaling of an ozone laundering system for space station may have commercial applications in a consumer model for home use.

Evaluation of Fenton and ozone-based advanced oxidation processes as mature landfill leachate pre-treatments.

PubMed

Cortez, Susana; Teixeira, Pilar; Oliveira, Rosário; Mota, Manuel

2011-03-01

Fenton treatment (Fe(2+)/H(2)O(2)) and different ozone-based Advanced Oxidation Processes (AOPs) (O(3), O(3)/OH(-) and O(3)/H(2)O(2)) were evaluated as pre-treatment of a mature landfill leachate, in order to improve the biodegradability of its recalcitrant organic matter for subsequent biological treatment. With a two-fold diluted leachate, at optimised experimental conditions (initial pH 3, H(2)O(2) to Fe(2+) molar ratio of 3, Fe(2+) dosage of 4 mmol L(-1), and reaction time of 40 min) Fenton treatment removed about 46% of chemical oxygen demand (COD) and increased the five-day biochemical oxygen demand (BOD(5)) to COD ratio (BOD(5)/COD) from 0.01 to 0.15. The highest removal efficiency and biodegradability was achieved by ozone at higher pH values, solely or combined with H(2)O(2). These results confirm the enhanced production of hydroxyl radical under such conditions. After the application for 60 min of ozone at 5.6 g O(3)h(-1), initial pH 7, and 400 mg L(-1) of hydrogen peroxide, COD removal efficiency was 72% and BOD(5)/COD increased from 0.01 to 0.24. An estimation of the operating costs of the AOPs processes investigated revealed that Fe(2+)/H(2)O(2) was the most economical system (8.2 € m(-3)g(-1) of COD removed) to treat the landfill leachate. This economic study, however, should be treated with caution since it does not consider the initial investment, prices at plant scale, maintenance and labour costs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Comparison of UV/hydrogen peroxide, potassium ferrate(VI), and ozone in oxidizing the organic fraction of oil sands process-affected water (OSPW).

PubMed

Wang, Chengjin; Klamerth, Nikolaus; Messele, Selamawit Ashagre; Singh, Arvinder; Belosevic, Miodrag; Gamal El-Din, Mohamed

2016-09-01

The efficiency of three different oxidation processes, UV/H2O2 oxidation, ferrate(VI) oxidation, and ozonation with and without hydroxyl radical (OH) scavenger tert-butyl alcohol (TBA) on the removal of organic compounds from oil sands process-affected water (OSPW) was investigated and compared. The removal of aromatics and naphthenic acids (NAs) was explored by synchronous fluorescence spectra (SFS), ion mobility spectra (IMS), proton and carbon nuclear magnetic resonance ((1)H and (13)C NMR), and ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC TOF-MS). UV/H2O2 oxidation occurred through radical reaction and photolysis, transforming one-ring, two-ring, and three-ring fluorescing aromatics simultaneously and achieving 42.4% of classical NAs removal at 2.0 mM H2O2 and 950 mJ/cm(2) UV dose provided with medium pressure mercury lamp. Ferrate(VI) oxidation exhibited high selectivity, preferentially removing two-ring and three-ring fluorescing aromatics, sulfur-containing NAs (NAs + S), and NAs with high carbon and high hydrogen deficiency. At 2.0 mM Fe(VI), 46.7% of classical NAs was removed. Ozonation achieved almost complete removal of fluorescing aromatics, NAs + S, and classical NAs (NAs with two oxygen atoms) at the dose of 2.0 mM O3. Both molecular ozone reaction and OH reaction were important pathways in transforming the organics in OSPW as supported by ozonation performance with and without TBA. (1)H NMR analyses further confirmed the removal of aromatics and NAs both qualitatively and quantitatively. All the three oxidation processes reduced the acute toxicity towards Vibrio fischeri and on goldfish primary kidney macrophages (PKMs), with ozonation being the most efficient. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2013-10-01

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.

Application of ozonation for pharmaceuticals and personal care products removal from water.

PubMed

Gomes, João; Costa, Raquel; Quinta-Ferreira, Rosa M; Martins, Rui C

2017-05-15

Due to the shortening on natural water resources, reclaimed wastewater will be an important water supply source. However, suitable technologies must be available to guaranty its proper detoxification with special concern for the emerging pharmaceutical and personal care products that are continuously reaching municipal wastewater treatment plants. While conventional biological systems are not suitable to remove these compounds, ozone, due to its interesting features involving molecular ozone oxidation and the possibility of generating unselective hydroxyl radicals, has a wider range of action on micropollutants removal and water disinfection. This paper aims to review the studies dealing with ozone based processes for water reuse by considering municipal wastewater reclamation as well as natural and drinking water treatment. A comparison with alternative technologies is given. The main drawback of ozonation is related with the low mineralization achieved that may lead to the production of reaction intermediates with toxic features. The use of hydrogen peroxide and light aided systems enhance ozone action over pollutants. Moreover, scientific community is focused on the development of solid catalysts able to improve the mineralization level achieved by ozone. Special interest is now being given to solar light catalytic ozonation systems with interesting results both for chemical and biological contaminants abatement. Nowadays the integration between ozonation and sand biofiltration seems to be the most interesting cost effective methodology for water treatment. However, further studies must be performed to optimize this system by understanding the biofiltration mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Villalta, P. W.; Zahniser, M. S.; Nelson, D. D.; Kolb, C. E.

1998-01-01

This is the final report for this project. Its purpose is to reduce the uncertainty in rate coefficients for key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring the rate coefficients for the reactions of HO2 + O3, and HO2 + NO2 in the temperature range (200-240 K) relevant to the lower stratosphere. In order to accomplish this, a high pressure turbulent flow tube reactor was built and its flow characteristics were quantified. The instrument was coupled with tunable diode laser spectroscopy for HO2 detection. Room temperature measurements of the HO2 + NO2 rate coefficients over the pressure range of 50-300 torr agree well with previous measurements. Preliminary measurements of the HO2 + O, rate coefficients at 50 - 300 Torr over the temperature range of 208-294 K agree with the NASA evaluation from 294-225 K but deviate significantly (50 % higher) at approximately 210 K.

Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu Amr, Salem S.; Aziz, Hamidi Abdul, E-mail: cehamidi@eng.usm.my; Adlan, Mohd Nordin

Highlights: ► Ozone and persulfate reagent (O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) was used to treat stabilized leachate. ► Central composite design (CCD) with response surface methodology (RSM) was applied. ► Operating variables including ozone and persulfate dosage, pH variance, and reaction time. ► Optimum removal of COD, color, and NH{sub 3}–N was 72%, 96%, and 76%, respectively. ► A good value of ozone consumption (OC) obtained with 0.60 (kg O{sub 3}/kg COD). - Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate inmore » an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH{sub 3}–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m{sup 3} ozone, 1 g/1 g COD{sub 0}/S{sub 2}O{sub 8}{sup 2-} ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH{sub 3}–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O{sub 3}/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S{sub 2}O{sub 8}{sup 2-} only, to evaluate its effectiveness. The combined method (i.e., O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) achieved higher removal efficiencies for COD, color, and NH{sub 3}–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.« less

Ozone therapy in periodontics

PubMed Central

Gupta, G; Mansi, B

2012-01-01

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. PMID:22574088

Ozone therapy in periodontics.

PubMed

Gupta, G; Mansi, B

2012-02-22

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.

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

ERIC Educational Resources Information Center

Christidou, Vasilia; Koulaidis, Vasilis

1996-01-01

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

The Nevada Rural Ozone Initiative: Field measurements of surface ozone in rural settings

NASA Astrophysics Data System (ADS)

Fine, R.; Gustin, M. S.; Weiss-Penzias, P. S.; Jaffe, D. A.; Peterson, C.

2011-12-01

The Nevada Rural Ozone Initiative (NVROI) focuses on measuring ozone and other parameters at rural sites across Nevada. The project was prompted by observations of elevated ozone concentrations at Great Basin National Park (GBNP), a remote location at the eastern boundary of the state. Past CASTNET data collected at GBNP demonstrated that the area will be out of attainment if the new ozone NAAQS are established at any values between 60 and 70 ppb. To examine the ozone sources we have augmented the CASTNET data at GBNP with measurements at additional sites. NVROI field sites are situated between 1390 and 2080 meters above sea level along transects consistent with the prevailing wind directions across the state. Data collection began in July 2011. Measurements indicate significant variability in the diel pattern of ozone concentrations between field sites suggesting that site specific physicochemical characteristics, free tropospheric inputs, and regional transport of air pollutants all influence observed values at these background sites. Ancillary gas, particulate matter, and meteorological parameters will be coupled with trajectory analyses to investigate the influence of local, regional, and long range sources on background ozone concentrations.

Process Analysis of Typhoon Related Ozone Pollution over the Pearl River Delta during the PRIDE-PRD2006

NASA Astrophysics Data System (ADS)

Li, Y.; Wang, X.; Zhang, Y.

2014-12-01

There were two typhoon processes during Campaign PRIDE-PRD2006 in July 2006 and serious ozone pollution episodes occurred before the landing of the typhoons. Chemical transport model CMAQ was employed in this work to simulate the ozone pollution episode related by the typhoon KAEMI. According to the meteorological conditions, the pollution episode could be divided into three phases with the movement of the typhoon, which were (1) far away from the continent; (2) coming close to the continent; (3) before landing. Process analysis was applied to get the contributions of physical and chemical processes for the ozone. It revealed that transport process was dominant during this pollution episode, and the influence of chemical process increased in the second phase. Three typical regions, northern rural area, urban area and Hong Kong area, were selected to study the contribution of each chemical and physical process. In the first phase, the primary process in northern rural area and the urban area was vertical diffusion, accounting for 47% and 46% respectively. In the second phase, the primary process in northern rural area and the urban area was chemical process, accounting for 33% and 31% respectively. In the third phase, the region of high concentration ozone moved southward. For Hong Kong area, the western inflow was prominent as 40%. Sensitivity study showed that urban areas were VOCs-limited regime with decreased ozone concentration when reducing the emission of VOCs. On the contrary, the ozone concentration in downwind rural areas decreased with the reduction of NOx, and the reason may be the decrement of the accumulated precursors.

Degradation of recalcitrant naphthenic acids from raw and ozonated oil sands process-affected waters by a semi-passive biofiltration process.

PubMed

Zhang, Lei; Zhang, Yanyan; Gamal El-Din, Mohamed

2018-04-15

In this study, a fixed-bed biofiltration system (biofilter) that utilized indigenous microorganisms was developed for the reclamation of oil sands process-affected water (OSPW). With the assistance of quantitative polymerase chain reaction (qPCR) and confocal laser scanning microscopy (CLSM), indigenous microorganisms from OSPW were able to attach to the surface of sand media and form biofilms. The number of total bacteria on the biofilter media reached a steady state (10 9 /g) after 23 days of operation. Ultra Performance Liquid Chromatography/High Resolution Mass Spectrometry (UPLC/HRMS) analysis showed that 21.8% of the classical naphthenic acids (NAs) removal was achieved through the circulation of raw OSPW on the biofilter for 8 times (equivalent to a hydraulic retention time of 16 h). When ozonation with utilized ozone dose of 30 mg/L was applied as pretreatment, the classical NAs in the ozonated OSPW were removed by 89.3% with an accelerated biodegradation rate of 0.5 mg/L/h. Compared with other biofilm reactors such as moving bed biofilm reactor (MBBR), ozonation pretreatment could benefit the biodegradation of NAs in the biofilter more (classical NA removal: 89.3% vs. 34.4%), especially for those with high carbon number and cyclicity. The combined ozonation-biofiltration process could remove 92.7% of classical NAs from raw OSPW in 16 h. Although both ozonation and biofiltration alone did not show degradation of oxidized NAs from raw OSPW, the combined process led to a 52.9% and 42.6% removal for O 3 -NAs and O 4 -NAs, respectively, which were the dominant oxidized NA species in OSPW. Metagenomic sequencing analysis showed that Rhodococcus was the dominant bacterial genus on the sand media, which may play a crucial role during the NA biodegradation. With the advantage of high NA removal efficiency, the combined ozonation-biofiltration process is a promising approach for NA degradation and shows high potential to be scaled up for in-situ OSPW

Ozone decrease outside Arctic polar vortex due to polar vortex processing in 1997

NASA Astrophysics Data System (ADS)

Akiyoshi, H.; Sugata, S.; Yoshiki, M.; Sugita, T.

2006-11-01

We examine the effect of polar vortex processing on ozone concentrations outside the 1997 Arctic polar vortex. The Arctic vortex in this year was well isolated, cold, and circumpolar, and it broke up unusually late. However, time threshold diagnostics (TTD) analysis using a middle vortex boundary defined by the first derivative of the equivalent latitude gradient of potential vorticity and calculations using the nudging chemical transport model (CTM) of the Center for Climate System Research/National Institute for Environmental Studies (CCSR/NIES) show that there were intermittently several relatively large transport events from the vortex to the outside region in the lower stratosphere, with timescales and spatial scales that can be resolved at T42 CTM horizontal resolution (2.8° by 2.8° grid). These intermittent outflow events of polar air are also identified in TTD analysis using an outer vortex boundary defined by the second derivative of potential vorticity and a boundary defined by the N2O concentration. These intermittent events had a significant effect on the ozone concentration outside the vortex near the boundary in this year. A CTM calculation with a polar chemical ozone tracer shows that the effect on the ozone concentration outside the polar vortex near the vortex boundary in the equivalent latitude band of 55°-65°N and 450 K is 0.3 ppmv (15-20% of the ozone concentration at this height) and that on the total ozone is 12-15 Dobson units (1 DU = 0.001 atm cm) (3-4% of the total ozone) by the end of April just before the final vortex breakup. The effect in the equivalent latitude band of 30°-60°N is much smaller, with a reduction of 2 DU at the end of March and 4 DU by the end of April (less than 1% of the total ozone). The effect is about the half if we use the inner boundary or a boundary of 73°N equivalent latitude for the polar tracer calculations. The CTM calculations also show that these polar vortex processing effects might be masked at

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

NASA Technical Reports Server (NTRS)

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

2012-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

CORONA-INDUCED OZONATION COUPLED WITH PHOTOOXIDATION: AN ENVIRONMENTALLY FRIENDLY AND COST-EFFECTIVE METHOD

EPA Science Inventory

We have developed a process that uses surface corona for the production of ozone by passing air or oxygen through a high voltage electrical discharge and the emitted ultraviolet light is being used to activate a photocatalyst. A thin film of nanostructured TiO2 with primary part...

Ozonation kinetics of winery wastewater in a pilot-scale bubble column reactor.

PubMed

Lucas, Marco S; Peres, José A; Lan, Bing Yan; Li Puma, Gianluca

2009-04-01

The degradation of organic substances present in winery wastewater was studied in a pilot-scale, bubble column ozonation reactor. A steady reduction of chemical oxygen demand (COD) was observed under the action of ozone at the natural pH of the wastewater (pH 4). At alkaline and neutral pH the degradation rate was accelerated by the formation of radical species from the decomposition of ozone. Furthermore, the reaction of hydrogen peroxide (formed from natural organic matter in the wastewater) and ozone enhances the oxidation capacity of the ozonation process. The monitoring of pH, redox potential (ORP), UV absorbance (254 nm), polyphenol content and ozone consumption was correlated with the oxidation of the organic species in the water. The ozonation of winery wastewater in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modeled by the two-film theory of mass transfer and chemical reaction. It was determined that the ozonation reaction can develop both in and across different kinetic regimes: fast, moderate and slow, depending on the experimental conditions. The dynamic change of the rate coefficient estimated by the model was correlated with changes in the water composition and oxidant species.

[Degradation of p-nitrophenol by high voltage pulsed discharge and ozone processes].

PubMed

Pan, Li-li; Yan, Guo-qi; Zheng, Fei-yan; Liang, Guo-wei; Fu, Jian-jun

2005-11-01

The vigorous oxidation by ozone and the high energy by pulsed discharge are utilized to degrade the big hazardous molecules. And these big hazardous molecules become small and less hazardous by this process in order to improve the biodegradability. When pH value is 8-9, the concentration of p-nitrophenol solution can be degraded by 96.8% and the degradation efficiency of TOC is 38.6% by ozone and pulsed discharge treatment for 30 mins. The comparison results show that the combination treatment efficiency is higher than the separate, so the combination of ozone and pulsed discharge has high synergism. It is approved that the phenyl degradation efficiency is high and the degradation efficiency of linear molecules is relative low.

CALIBRATION OF FULL-SCALE OZONATION SYSTEMS WITH CONSERVATIVE AND REACTIVE TRACERS

EPA Science Inventory

A full-scale ozonation reactor was characterized with respect to the overall oxidation budget by coupling laboratory kinetics with reactor hydraulics. The ozone decomposition kinetics and the ratio of the OH radical to the ozone concentration were determined in laboratory batch ...

Efficiency of combined process of ozone and bio-filtration in the treatment of secondary effluent.

PubMed

Tripathi, Smriti; Tripathi, B D

2011-07-01

The present work was aimed at studying the efficiency of the combined process of biofiltration with ozonation to improve the quality of secondary effluent. The secondary effluent from the Dinapur Sewage Treatment Plant Varanasi, India was used in this work. The process of biofiltration with the plant species of Eichornia crassipes and Lemna minor, at a flow rate of 262 ml min(-1) and plant density of 30 mg L(-1) for 48 h, in combination with the process of ozonation with ozone dose of 10 mg L(-1) and contact time of 5 min was applied. Results revealed that combined process was statistically most suitable for the highest degradation of physico-chemical and microbial parameters with improving BDOC value. The biofiltration process is able to remove highest percentage of toxic heavy metals from the secondary effluent without production of toxicity. This technique is highly recommendable for tropical wastewater where sewage is mixed with industrial effluents. Copyright © 2011 Elsevier Ltd. All rights reserved.

Treatment of oil sands process-affected water using moving bed biofilm reactors: With and without ozone pretreatment.

PubMed

Shi, Yijing; Huang, Chunkai; Rocha, Ketley Costa; El-Din, Mohamed Gamal; Liu, Yang

2015-09-01

Two moving bed biofilm reactors (MBBRs) were operated to treat raw (untreated) and 30 mg/L ozone-treated oil sands process-affected water (OSPW). After 210 days, the MBBR process showed 18.3% of acid-extractable fraction (AEF) and 34.8% of naphthenic acids (NAs) removal, while the ozonation combined MBBR process showed higher removal of AEF (41.0%) and NAs (78.8%). Biodegradation of raw and ozone treated OSPW showed similar performance. UPLC/HRMS analysis showed a highest NAs removal efficiency with a carbon number of 14 and a -Z number of 4. Confocal laser scanning microscopy (CLSM) showed thicker biofilms in the raw OSPW MBBR (97 ± 5 μm) than in the ozonated OSPW MBBR (71 ± 12 μm). Quantitative polymerase chain reaction (q-PCR) results showed higher abundance of gene copies of total bacteria and nitrogen removal relevant bacteria in the ozonated OSPW MBBR, but no significant difference was found. MiSeq sequencing showed Proteobacteria, Nitrospirae, and Acidobacteria were dominant. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ozone kinetics in low-pressure discharges

NASA Astrophysics Data System (ADS)

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

2012-10-01

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

A method for retrieving vertical ozone profiles from limb scattered measurements

NASA Astrophysics Data System (ADS)

Wang, Zijun; Chen, Shengbo; Yang, Chunyan; Jin, Lihua

2011-10-01

A two-step method is employed in this study to retrieve vertical ozone profiles using scattered measurements from the limb of the atmosphere. The combination of the Differential Optical Absorption Spectroscopy (DOAS) and the Multiplicative Algebraic Reconstruction Technique (MART) is proposed. First, the limb radiance, measured over a range of tangent heights, is processed using the DOAS technique to recover the effective column densities of atmospheric ozone. Second, these effective column densities along the lines of sight (LOSs) are inverted using the MART coupled with a forward model SCIATRAN (radiative transfer model for SCIAMACHY) to derive the ozone profiles. This method is applied to Optical Spectrograph and Infra Red Imager System (OSIRIS) radiance, using the wavelength windows 571-617 nm. Vertical ozone profiles between 10 and 48 km are derived with a vertical resolution of 1 km. The results illustrate a good agreement with the cloud-free coincident SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) ozone measurements, with deviations less than ±10% (±5% for altitudes from 17 to 47 km). Furthermore, sensitivities of retrieved ozone to aerosol, cloud parameters and NO2 concentration are also investigated.

Ozonation of the food dye Brilliant Blue in aqueous medium: monitoring and characterization of products by direct infusion electrospray ionization coupled to high-resolution mass spectrometry.

PubMed

da Silva, Júlio César Cardoso; Bispo, Glayson Leonardo; Pavanelli, Sérgio Pinton; Afonso, Robson José de Cássia Franco; Augusti, Rodinei

2012-06-15

Dyes have been widely used to accentuate or to provide different colors to foods. However, the high concentrations of dyes in effluents from the food industries can cause serious and unpredictable damages to aquatic life in general. Furthermore, since conventional biological treatments have been shown to be ineffective, the use of advanced oxidation processes to promote the depletion of such dyes in water bodies has turned out to be mandatory. The degradation of the food dye Brilliant Blue by ozone in aqueous solution is reported herein. The overall process was monitored in real time by using direct infusion electrospray ionization high-resolution mass spectrometry in the negative ion mode, ESI(-)-HRMS. Preliminary results (visual inspection and UV-vis spectra) showed the high efficiency of ozonation in causing the decoloration of an aqueous solution of the dye whereas TOC (total organic carbon) measurements revealed that such an oxidation process was unable to promote its complete mineralization. ESI(-)-HRMS data showed that the substrate consumption occurred concomitantly with the appearance of four by-products, all of them produced by an initial attack of hydroxyl radicals (generated via the decomposition of ozone) on the two imino moieties of the dye molecule. Structures were proposed for all the by-products based mainly on the high-resolution mass measurements and on the characteristic reactivity of typical functional groups towards hydroxyl radicals. An unprecedented degradation route of Brilliant Blue by ozone in aqueous solution could thus be proposed. A greater ecotoxicity against Artemia salina was observed for the by-products than for the original dye. This indicates that the identification of by-products arising from oxidation treatments is of primary importance since such compounds can be more hazardous than the precursor itself. Copyright © 2012 John Wiley & Sons, Ltd.

Decrease of summer tropospheric ozone concentrations in Antarctica

NASA Technical Reports Server (NTRS)

Schnell, R. C.; Stone, R. S.; Liu, S. C.; Oltmans, S. J.; Hofmann, D. J.

1991-01-01

It is shown here that surface ozone concentrations at the South Pole in the austral summer decreased by 17 percent over the period 1976-90. Over the same period, solar irradiance at the South Pole in January and February decreased by 7 percent as a result of a 25 percent increase in cloudiness. It is suggested that the trend in the summer ozone concentrations is caused by enhanced photochemical destruction of ozone in the lower troposphere caused by the increased penetration of UV radiation associated with stratospheric ozone depletion, coupled with enhanced transport of ozone-poor marine air from lower latitudes to the South Pole.

Bio oil synthesis by coupling biological biomass pretreatment and catalytic hydroliquefaction process.

PubMed

Hamieh, S; Beauchet, R; Lemee, L; Toufaily, J; Koubaissy, B; Hamieh, T; Pouilloux, Y; Pinard, L

2014-03-01

The bio-oil synthesis from a mixture of wastes (7wt.% straw, 38wt.% wood, and 45wt.% grass) was carried out by direct liquefaction reaction using Raney Nickel as catalyst and tetralin as solvent. The green wastes were biologically degraded during 3 months. Longer the destructuration time; higher the yield into oil is. Biological pretreatment of green wastes promotes the liquefaction process. Among the components of degraded biomass, Humin, the major fraction (60-80wt.%) that was favored by the biological treatment, yields to a bio oil extremely energetic with a HHV close to biopetroleum (40MJ kg(-1)), contrariwise, Fulvic acids (2-12wt.%), the minor fraction is refractory to liquefaction reaction. Copyright © 2014 Elsevier Ltd. All rights reserved.

Iron decreases biological effects of ozone exposure

EPA Science Inventory

CONTEXT: Ozone (0(3)) exposure is associated with a disruption of iron homeostasis and increased availability of this metal which potentially contributes to an oxidative stress and biologicaleffects. OBJECTIVE: We tested the postulate that increased concentrations of iron in c...

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

NASA Astrophysics Data System (ADS)

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

2010-12-01

The Montreal Protocol on Substances that Deplete the Ozone Layer was negotiated in 1987 and by 2010 had been signed by all of the nations of the world. In this presentation we use a fully coupled radiation-chemical-dynamical model to simulate a future world where ozone depletion substances (ODSs) were never regulated. In this “world avoided” simulation, ODS levels increase by 3% per year. From 1980 to 2020 we find that 17% of the globally average column ozone is destroyed, and from 1980 to 2065 67% is destroyed. Severe polar depletions (e.g., the Antarctic ozone hole) become year-round rather than just seasonal. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical lower stratospheric upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

NASA Astrophysics Data System (ADS)

Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.; Kinahan, Sean; Corson, Elizabeth; Eshbaugh, Jonathan; Santarpia, Joshua L.

2015-03-01

Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometer (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.

Inactivation characteristics of ozone and electrolysis process for ballast water treatment using B. subtilis spores as a probe.

PubMed

Jung, Youmi; Yoon, Yeojoon; Hong, Eunkyung; Kwon, Minhwan; Kang, Joon-Wun

2013-07-15

Since ballast water affects the ocean ecosystem, the International Maritime Organization (IMO) sets a standard for ballast water management and might impose much tighter regulations in the future. The aim of this study is to evaluate the inactivation efficiency of ozonation, electrolysis, and an ozonation-electrolysis combined process, using B. subtilis spores. In seawater ozonation, HOBr is the key active substance for inactivation, because of rapid reactivity of ozone with Br(-) in seawater. In seawater electrolysis, it is also HOBr, but not HOCl, because of the rapid reaction of HOCl with Br(-), which has not been recognized carefully, even though many electrolysis technologies have been approved by the IMO. Inactivation pattern was different in ozonation and electrolysis, which has some limitations with the tailing or lag-phase, respectively. However, each deficiency can be overcome with a combined process, which is most effective as a sequential application of ozonation followed by electrolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Constraining global dry deposition of ozone: observations and modeling

NASA Astrophysics Data System (ADS)

Silva, S. J.; Heald, C. L.

2016-12-01

Ozone loss through dry deposition to vegetation is a critically important process for both air quality and ecosystem health. Current estimates are that nearly 25% of all surface ozone is destroyed through dry deposition, and billions of dollars are lost annually due to losses of ecosystem services and agricultural yield associated with ozone damage. However there are still substantial uncertainties regarding the spatial distribution and magnitude of the global depositional flux. As land cover change continues throughout this century, dry deposition of ozone will change in ways that are yet still poorly understood. Nearly every major atmospheric chemistry model uses a variation of the "resistor in series parameterization" for the calculation of dry deposition. By far the most commonly implemented parameterization is of the form presented in Wesely (1989), and is dependent on many variables, including land type look up tables, solar radiation, leaf area index, temperature, and more. The uncertainties contained within the various parts of this parameterization have to date not been fully explored. A lack of understanding of these uncertainties, coupled with a dearth of routine measurements of ozone deposition, ultimately challenges our ability to understand the impacts of land cover change on surface ozone. In this work, we use a suite of globally-distributed observations from the past two decades and the GEOS-Chem chemical transport model to constrain global dry deposition, improve our understanding of these uncertainties, and contextualize the impact of land cover change on ozone concentrations.

Ozone-UV-catalysis based advanced oxidation process for wastewater treatment.

PubMed

Tichonovas, Martynas; Krugly, Edvinas; Jankunaite, Dalia; Racys, Viktoras; Martuzevicius, Dainius

2017-07-01

A bench-scale advanced oxidation (AO) reactor was investigated for the degradation of six pollutants (2-naphthol, phenol, oxalic acid, phthalate, methylene blue, and D-glucose) in a model wastewater at with the aim to test opportunities for the further upscale to industrial applications. Six experimental conditions were designed to completely examine the experimental reactor, including photolysis, photocatalysis, ozonation, photolytic ozonation, catalytic ozonation, and photocatalytic ozonation. The stationary catalyst construction was made from commercially available TiO 2 nanopowder by mounting it on a glass support and subsequently characterized for morphology (X-ray diffraction analysis and scanning electron microscopy) as well as durability. The ozone was generated in a dielectrical barrier discharge reactor using air as a source of oxygen. The degradation efficiency was estimated by the decrease in total organic carbon (TOC) concentration as well as toxicity using Daphnia magna, and degradation by-products by ultra-performance liquid chromatography-mass spectrometry. The photocatalytic ozonation was the most effective for the treatment of all model wastewater. The photocatalytic ozonation was most effective against ozonation and photolytic ozonation at tested pH values. A complete toxicity loss was obtained after the treatment using photocatalytic ozonation. The possible degradation pathway of the phthalate by oxidation was suggested based on aromatic ring opening reactions. The catalyst used at this experiment confirmed as a durable for continuous use with almost no loss of activity over time. The design of the reactor was found to be very effective for water treatment using photocatalytic ozonation. Such design has a high potential and can be further upscaled to industrial applications due to the simplicity and versatility of manufacturing and maintenance.

Impact of Ozone Radiative Feedbacks on Global Weather Forecasting

NASA Astrophysics Data System (ADS)

Ivanova, I.; de Grandpré, J.; Rochon, Y. J.; Sitwell, M.

2017-12-01

A coupled Chemical Data Assimilation system for ozone is being developed at Environment and Climate Change Canada (ECCC) with the goals to improve the forecasting of UV index and the forecasting of air quality with the Global Environmental Multi-scale (GEM) Model for Air quality and Chemistry (MACH). Furthermore, this system provides an opportunity to evaluate the benefit of ozone assimilation for improving weather forecasting with the ECCC Global Deterministic Prediction System (GDPS) for Numerical Weather Prediction (NWP). The present UV index forecasting system uses a statistical approach for evaluating the impact of ozone in clear-sky and cloudy conditions, and the use of real-time ozone analysis and ozone forecasts is highly desirable. Improving air quality forecasting with GEM-MACH further necessitates the development of integrated dynamical-chemical assimilation system. Upon its completion, real-time ozone analysis and ozone forecasts will also be available for piloting the regional air quality system, and for the computation of ozone heating rates, in replacement of the monthly mean ozone distribution currently used in the GDPS. Experiments with ozone radiative feedbacks were run with the GDPS at 25km resolution and 84 levels with a lid at 0.1 hPa and were initialized with ozone analysis that has assimilated total ozone column from OMI, OMPS, and GOME satellite instruments. The results show that the use of prognostic ozone for the computation of the heating/cooling rates has a significant impact on the temperature distribution throughout the stratosphere and upper troposphere regions. The impact of ozone assimilation is especially significant in the tropopause region, where ozone heating in the infrared wavelengths is important and ozone lifetime is relatively long. The implementation of the ozone radiative feedback in the GDPS requires addressing various issues related to model biases (temperature and humidity) and biases in equilibrium state (ozone mixing

Ozone depletion - Ultraviolet radiation and phytoplankton biology in Antarctic waters

NASA Technical Reports Server (NTRS)

Smith, R. C.; Prezelin, B. B.; Baker, K. S.; Bidigare, R. R.; Boucher, N. P.; Coley, T.; Karentz, D.; Macintyre, S.; Matlick, H. A.; Menzies, D.

1992-01-01

The near-50-percent thinning of the stratospheric ozone layer over the Antarctic, with increased passage of mid-UV radiation to the surface of the Southern Ocean, has prompted concern over possible radiation damage to the near-surface phytoplankton communities that are the bases of Antarctic marine ecosystems. As the ozone layer thinned, a 6-week study of the marginal ice zone of the Bellingshousen Sea in the austral spring of 1990 noted sea-surface and depth-dependent ratios of mid-UV irradiance to total irradiance increased, and mid-UV inhibition of photosynthesis increased. A 6-12 percent reduction in primary production associated with ozone depletion was estimated to have occurred over the course of the present study.

RESULTS OF RESEARCH RELATED TO STRATOSPHERIC OZONE PROTECTION

EPA Science Inventory

Research on ozone protection has been coordinated under the Biological and Climatic Effects Research (BACER) Program. This is a multiagency, multidisciplinary effort initially funded by The Environmental Protection Agency. Its purpose is to reduce uncertainties regarding ozone de...

Optimization of Ozonation Process for the Reduction of Excess Sludge Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

PubMed Central

Subha, B.; Muthukumar, M.

2012-01-01

Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (R 2) of VSS and COD reduction were 0.9689 and 0.8838, respectively. VSS reduction (81%) was achieved at acidic pH 6.9, 12 minutes ozonation, and retention time of 10 days. COD reduction (87%) was achieved at acidic pH 6.7, 8 minutes of ozonation time, and retention time of 6 days. Low ozonation time and high retention time influence maximum sludge reduction, whereas low ozonation time with low retention time was effective for COD reduction. PMID:22593666

The impacts of ozonation on oil sands process-affected water biodegradability and biofilm formation characteristics in bioreactors.

PubMed

Hwang, Geelsu; Dong, Tao; Islam, Md Sahinoor; Sheng, Zhiya; Pérez-Estrada, Leónidas A; Liu, Yang; Gamal El-Din, Mohamed

2013-02-01

To examine the effects of the ozonation process (as an oxidation treatment for water and wastewater treatment applications) on microbial biofilm formation and biodegradability of organic compounds present in oil sands process-affected water (OSPW), biofilm reactors were operated continuously for 6weeks. Two types of biofilm substrate materials: polyethylene (PE) and polyvinylchloride (PVC), and two types of OSPW-fresh and ozonated OSPWs-were tested. Endogenous microorganisms, in OSPW, quickly formed biofilms in the reactors. Without ozonation, the bioreactor (using endogenous microorganisms) removed 13.8% of the total acid-extractable organics (TAO) and 18.5% of the parent naphthenic acids (NAs) from fresh OSPW. The combined ozonation and biodegradation process removed 87.2% of the OSPW TAO and over 99% of the OSPW parent NAs. Further UPLC/HRMS analysis showed that NA biodegradability decreased as the NA cyclization number increased. Microbial biofilm formation was found to depend on the biofilm substrate type. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

PubMed

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

2013-04-01

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). Copyright © 2013 Elsevier Ltd. All rights reserved.

Statistical estimation of ozone exposure metrics

NASA Astrophysics Data System (ADS)

Blankenship, Erin E.; Stefanski, L. A.

Data from recent experiments at North Carolina State University and other locations provide a unique opportunity to study the effect of ambient ozone on the growth of clover. The data consist of hourly ozone measurements over a 140 day growing season at eight sites in the US, coupled with clover growth response data measured every 28 days. The objective is to model an indicator of clover growth as a function of ozone exposure. A common strategy for dealing with the numerous hourly ozone measurements is to reduce these to a single summary measurement, a so-called exposure metric, for the growth period of interest. However, the mean ozone value is not necessarily the best summarization, as it is widely believed that low levels of ozone have a negligible effect on growth, whereas peak ozone values are deleterious to plant growth. There are also suspected interactions with available sunlight, temperature and humidity. A number of exposure metrics have been proposed that reflect these beliefs by assigning different weights to ozone values according to magnitude, time of day, temperature and humidity. These weighting schemes generally depend on parameters that have, to date, been subjectively determined. We propose a statistical approach based on profile likelihoods to estimate the parameters in these exposure metrics.

Influence of ozonation and biodegradation on toxicity of industrial textile wastewater.

PubMed

Paździor, Katarzyna; Wrębiak, Julita; Klepacz-Smółka, Anna; Gmurek, Marta; Bilińska, Lucyna; Kos, Lech; Sójka-Ledakowicz, Jadwiga; Ledakowicz, Stanisław

2017-06-15

The textile industry demands huge volumes of high quality water which converts into wastewater contaminated by wide spectrum of chemicals. Estimation of textile wastewater influence on the aquatic systems is a very important issue. Therefore, closing of the water cycle within the factories is a promising method of decreasing its environmental impact as well as operational costs. Taking both reasons into account, the aim of this work was to establish the acute toxicity of the textile wastewater before and after separate chemical, biological as well as combined chemical-biological treatment. For the first time the effects of three different combinations of chemical and biological methods were investigated. The acute toxicity analysis were evaluated using the Microtox ® toxicity test. Ozonation in two reactors of working volume 1 dm 3 (stirred cell) and 20 dm 3 (bubble column) were tested as chemical process, while biodegradation was conducted in two, different systems - Sequence Batch Reactors (SBR; working volume 1.5 dm 3 ) and Horizontal Continuous Flow Bioreactor (HCFB; working volume 12 dm 3 ). The untreated wastewater had the highest toxicity (EC50 value in range: 3-6%). Ozonation caused lower reduction of the toxicity than biodegradation. In the system with SBR the best results were obtained for the biodegradation followed by the ozonation and additional biodegradation - 96% of the toxicity removal. In the second system (with HCFB) two-stage treatment (biodegradation followed by the ozonation) led to the highest toxicity reduction (98%). Copyright © 2016 Elsevier Ltd. All rights reserved.

[Research on the treatment of wastewater containing PVA by ozonation-activated sludge process].

PubMed

Xing, Xiao-Qiong; Huang, Cheng-Lan; Liu, Min; Chen, Ying

2012-11-01

The wastewater containing polyvinyl alcohol (PVA) was characterized with poor biodegradability, and was difficult to remove. In order to find an economically reasonable and practical technology, the research on the removal efficiency of different concentration wastewater containing PVA by ozonation-activated sludge process was studied, and the result was compared with the traditional activated sludge process. The results showed that the ozonation-activated sludge process was not suitable for treating influent with COD below 500 mg x L(-1) and the wastewater PVA concentration was 10-30 mg x L(-1). When the influent COD was between 500-800 mg x L(-1) and the PVA concentration was 15-60 mg x L(-1), the system had advantages on dealing with this kind of wastewater, and the average removal efficiency of COD and PVA were 92.8% and 57.4%, which were better than the traditional activated sludge process 4.1% and 15.2% respectively. In addition, the effluent concentrations of COD could keep between 30-60 mg x L(-1). When the influent COD was 1 000-1 200 mg x L(-1) and the PVA concentration was 20-70 mg x L(-1), the average removal efficiencies of COD and PVA were 90.9% and 45.3%, which were better than the traditional activated sludge process 12.8% and 12.1% respectively, but the effluent should to be further treated. Compared with the traditional activated sludge process, ozonation-activated sludge process had high treatment efficiency, stable running effect, and effectively in dealing with industrial wastewater containing PVA.

Naphthenic acids speciation and removal during petroleum-coke adsorption and ozonation of oil sands process-affected water.

PubMed

Gamal El-Din, Mohamed; Fu, Hongjing; Wang, Nan; Chelme-Ayala, Pamela; Pérez-Estrada, Leonidas; Drzewicz, Przemysław; Martin, Jonathan W; Zubot, Warren; Smith, Daniel W

2011-11-01

The Athabasca Oil Sands industry produces large volumes of oil sands process-affected water (OSPW) as a result of bitumen extraction and upgrading processes. Constituents of OSPW include chloride, naphthenic acids (NAs), aromatic hydrocarbons, and trace heavy metals, among other inorganic and organic compounds. To address the environmental issues associated with the recycling and/or safe return of OSPW into the environment, water treatment technologies are required. This study examined, for the first time, the impacts of pretreatment steps, including filtration and petroleum-coke adsorption, on ozonation requirements and performance. The effect of the initial OSPW pH on treatment performance, and the evolution of ozonation and its impact on OSPW toxicity and biodegradability were also examined. The degradation of more than 76% of total acid-extractable organics was achieved using a semi-batch ozonation system at a utilized ozone dose of 150 mg/L. With a utilized ozone dose of 100 mg/L, the treated OSPW became more biodegradable and showed no toxicity towards Vibrio fischeri. Changes in the NA profiles in terms of carbon number and number of rings were observed after ozonation. The filtration of the OSPW did not improve the ozonation performance. Petroleum-coke adsorption was found to be effective in reducing total acid-extractable organics by a 91%, NA content by an 84%, and OSPW toxicity from 4.3 to 1.1 toxicity units. The results of this study indicate that the combination of petroleum-coke adsorption and ozonation is a promising treatment approach to treat OSPW. Copyright © 2011 Elsevier B.V. All rights reserved.

Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

1996-01-01

The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HOx and NOx species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences.

The Antarctic ozone hole

NASA Technical Reports Server (NTRS)

Stolarski, Richard S.

1988-01-01

Processes that may be responsible for the thinning in the ozone layer above the South Pole are described. The chlorine catalytic cycle which destroys ozone is described, as are the major types of reactions that are believed to interfere with this cycle by forming chlorine reservoirs. The suspected contributions of polar stratospheric clouds to these processes are examined. Finally, the possibility that the ozone hole may be due more to a shift in atmospheric dynamics than to chemical destruction is addressed.

In vitro evaluation of wound healing and antimicrobial potential of ozone therapy.

PubMed

Borges, Gabriel Álvares; Elias, Silvia Taveira; da Silva, Sandra Márcia Mazutti; Magalhães, Pérola Oliveira; Macedo, Sergio Bruzadelli; Ribeiro, Ana Paula Dias; Guerra, Eliete Neves Silva

2017-03-01

Although ozone therapy is extensively applied when wound repair and antimicrobial effect are necessary, little is known about cellular mechanisms regarding this process. Thus, this study aimed to evaluate ozone cytotoxicity in fibroblasts (L929) and keratinocytes (HaCaT) cell lines, its effects on cell migration and its antimicrobial activity. Cells were treated with ozonated phosphate-buffered saline (8, 4, 2, 1, 0.5 and 0.25 μg/mL ozone), chlorhexidine 0.2% or buffered-solution, and cell viability was determined through MTT assay. The effect of ozone on cell migration was evaluated through scratch wound healing and transwell migration assays. The minimum inhibitory concentrations for Candida albicans and Staphylococcus aureus were determined. Ozone showed no cytotoxicity for the cell lines, while chlorhexidine markedly reduced cell viability. Although no significant difference between control and ozone-treated cells was observed in the scratch assay, a considerable increase in fibroblasts migration was noticed on cells treated with 8 μg/mL ozonated solution. Ozone alone did not inhibit growth of microorganisms; however, its association with chlorhexidine resulted in antimicrobial activity. This study confirms the wound healing and antimicrobial potential of ozone therapy and presents the need for studies to elucidate the molecular mechanisms through which it exerts such biological effects. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Impacts of Atmosphere-Ocean Coupling on Southern Hemisphere Climate Change

NASA Technical Reports Server (NTRS)

Li, Feng; Newman, Paul; Pawson, Steven

2013-01-01

Climate in the Southern Hemisphere (SH) has undergone significant changes in recent decades. These changes are closely linked to the shift of the Southern Annular Mode (SAM) towards its positive polarity, which is driven primarily by Antarctic ozone depletion. There is growing evidence that Antarctic ozone depletion has significant impacts on Southern Ocean circulation change. However, it is poorly understood whether and how ocean feedback might impact the SAM and climate change in the SH atmosphere. This outstanding science question is investigated using the Goddard Earth Observing System Coupled Atmosphere-Ocean-Chemistry Climate Model(GEOS-AOCCM).We perform ensemble simulations of the recent past (1960-2010) with and without the interactive ocean. For simulations without the interactive ocean, we use sea surface temperatures and sea ice concentrations produced by the interactive ocean simulations. The differences between these two ensemble simulations quantify the effects of atmosphere-ocean coupling. We will investigate the impacts of atmosphere-ocean coupling on stratospheric processes such as Antarctic ozone depletion and Antarctic polar vortex breakup. We will address whether ocean feedback affects Rossby wave generation in the troposphere and wave propagation into the stratosphere. Another focuson this study is to assess how ocean feedback might affect the tropospheric SAM response to Antarctic ozone depletion

A decontamination study of simulated chemical and biological agents

NASA Astrophysics Data System (ADS)

Uhm, Han S.; Lee, Han Y.; Hong, Yong C.; Shin, Dong H.; Park, Yun H.; Hong, Yi F.; Lee, Chong K.

2007-07-01

A comprehensive decontamination scheme of the chemical and biological agents, including airborne agents and surface contaminating agents, is presented. When a chemical and biological attack occurs, it is critical to decontaminate facilities or equipments to an acceptable level in a very short time. The plasma flame presented here may provide a rapid and effective elimination of toxic substances in the interior air in isolated spaces. As an example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies air with an airflow rate of 5000l/min contaminated with toluene, the simulated chemical agent, and soot from a diesel engine, the simulated aerosol for biological agents. Although the airborne agents in an isolated space are eliminated to an acceptable level by the plasma flame, the decontamination of the chemical and biological agents cannot be completed without cleaning surfaces of the facilities. A simulated sterilization study of micro-organisms was carried out using the electrolyzed ozone water. The electrolyzed ozone water very effectively kills endospores of Bacillus atrophaeus (ATCC 9372) within 3min. The electrolyzed ozone water also kills the vegetative micro-organisms, fungi, and virus. The electrolyzed ozone water, after the decontamination process, disintegrates into ordinary water and oxygen without any trace of harmful materials to the environment.

Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

DOE PAGES

Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.; ...

2015-10-14

Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometermore » (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.« less

Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.

Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometermore » (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.« less

Coupling chemical and biological catalysis: a flexible paradigm for producing biobased chemicals.

PubMed

Schwartz, Thomas J; Shanks, Brent H; Dumesic, James A

2016-04-01

Advances in metabolic engineering have allowed for the development of new biological catalysts capable of selectively de-functionalizing biomass to yield platform molecules that can be upgraded to biobased chemicals using high efficiency continuous processing allowed by heterogeneous chemical catalysis. Coupling these disciplines overcomes the difficulties of selectively activating COH bonds by heterogeneous chemical catalysis and producing petroleum analogues by biological catalysis. We show that carboxylic acids, pyrones, and alcohols are highly flexible platforms that can be used to produce biobased chemicals by this approach. More generally, we suggest that molecules with three distinct functionalities may represent a practical upper limit on the extent of functionality present in the platform molecules that serve as the bridge between biological and chemical catalysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process-scale modeling of elevated wintertime ozone in Wyoming.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotamarthi, V. R.; Holdridge, D. J.; Environmental Science Division

2007-12-31

Measurements of meteorological variables and trace gas concentrations, provided by the Wyoming Department of Environmental Quality for Daniel, Jonah, and Boulder Counties in the state of Wyoming, were analyzed for this project. The data indicate that highest ozone concentrations were observed at temperatures of -10 C to 0 C, at low wind speeds of about 5 mph. The median values for nitrogen oxides (NOx) during these episodes ranged between 10 ppbv and 20 ppbv (parts per billion by volume). Measurements of volatile organic compounds (VOCs) during these periods were insufficient for quantitative analysis. The few available VOCs measurements indicated unusuallymore » high levels of alkanes and aromatics and low levels of alkenes. In addition, the column ozone concentration during one of the high-ozone episodes was low, on the order of 250 DU (Dobson unit) as compared to a normal column ozone concentration of approximately 300-325 DU during spring for this region. Analysis of this observation was outside the scope of this project. The data analysis reported here was used to establish criteria for making a large number of sensitivity calculations through use of a box photochemical model. Two different VOCs lumping schemes, RACM and SAPRC-98, were used for the calculations. Calculations based on this data analysis indicated that the ozone mixing ratios are sensitive to (a) surface albedo, (b) column ozone, (c) NOx mixing ratios, and (d) available terminal olefins. The RACM model showed a large response to an increase in lumped species containing propane that was not reproduced by the SAPRC scheme, which models propane as a nearly independent species. The rest of the VOCs produced similar changes in ozone in both schemes. In general, if one assumes that measured VOCs are fairly representative of the conditions at these locations, sufficient precursors might be available to produce ozone in the range of 60-80 ppbv under the conditions modeled.« less

Potential For Stratospheric Ozone Depletion During Carboniferous

NASA Astrophysics Data System (ADS)

Bill, M.; Goldstein, A. H.

Methyl bromide (CH3Br) constitutes the largest source of bromine atoms to the strato- sphere whereas methyl chloride (CH3Cl) is the most abundant halocarbon in the tro- posphere. Both gases play an important role in stratospheric ozone depletion. For in- stance, Br coupled reactions are responsible for 30 to 50 % of total ozone loss in the polar vortex. Currently, the largest natural sources of CH3Br and CH3Cl appear to be biological production in the oceans, inorganic production during biomass burning and plant production in salt marsh ecosystems. Variations of paleofluxes of CH3Br and CH3Cl can be estimated by analyses of oceanic paleoproductivity, stratigraphic analyses of frequency and distribution of fossil charcoal indicating the occurrence of wildfires, and/or by paleoreconstruction indicating the extent of salt marshes. Dur- ing the lower Carboniferous time (Tournaisian-Visean), the southern margin of the Laurasian continent was characterized by charcoal deposits. Estimation on frequency of charcoal layers indicates that wildfires occur in a range of 3-35 years (Falcon-Lang 2000). This suggests that biomass burning could be an important source of CH3Br and CH3Cl during Tournaisian-Viesan time. During Tounaisian and until Merame- cian carbon and oxygen isotope records have short term oscillations (Bruckschen et al. 1999, Mii et al. 1999). Chesterian time (mid- Carboniferous) is marked by an in- crease in delta18O values ( ~ 2 permil) and an increase of glacial deposit frequency suggesting lower temperatures. The occurrence of glacial deposits over the paleopole suggests polar conditions and the associated special features of polar mete- orology such as strong circumpolar wind in the stratosphere (polar vortex) and polar stratospheric clouds. Thus, conditions leading to polar statospheric ozone depletion can be found. Simultaneously an increase in delta13C values is documented. We interpret the positive shift in delta13C as a result of higher bioproductivity

Required ozone doses for removing pharmaceuticals from wastewater effluents.

PubMed

Antoniou, Maria G; Hey, Gerly; Rodríguez Vega, Sergio; Spiliotopoulou, Aikaterini; Fick, Jerker; Tysklind, Mats; la Cour Jansen, Jes; Andersen, Henrik Rasmus

2013-07-01

The aim of the this study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality, originated from different raw wastewater and wastewater treatment processes. Secondary effluents from six Swedish wastewater treatment plants (WWTP) were spiked with 42 APIs (nominal concentration μg/L) and treated with different O₃ doses (0.5-12.0 mg/L ozone) in bench-scale experiments. In order to compare the sensitivity of APIs in each matrix, the specific dose of ozone required to achieve reduction by one decade of each investigated API (DDO₃) was determined for each effluent by fitting a first order equation to the remaining concentration of API at each applied ozone dose. Ozone dose requirements were found to vary significantly between effluents depending on their matrix characteristics. The specific ozone dose was then normalized to the dissolved organic carbon (DOC) of each effluent. The DDO₃/DOC ratios were comparable for each API between the effluents. 15 of the 42 investigated APIs could be classified as easily degradable (DDO₃/DOC ≤ 0.7), while 19 were moderately degradable (0.7 < DDO₃/DOC ≤ 1.4), and 8 were recalcitrant towards O₃-treatment (DDO₃/DOC >1.4). Furthermore, we predict that a reasonable estimate of the ozone dose required to remove any of the investigated APIs may be attained by multiplying the experimental average DDO₃/DOC obtained with the actual DOC of any effluent. Copyright © 2013 Elsevier B.V. All rights reserved.

Ozone measurements

NASA Technical Reports Server (NTRS)

Randhawa, J.

1978-01-01

The chemiluminescent ozonesonde to be flown with the STRATCOM balloon flight consisted of two main parts: (1) A constant-volume sampling pump made from TEFLON was used for the intake of the air sample. Sample was drawn at a rate of 200 millimeters per minute. (2) Ozone was detected by the chemiluminescent process (Rhodamine - B). Ozone molecules in the air sample flowed over the detector and the photons produced by the destruction of ozone molecules on the chemiluminescent material were monitored by the photomultiplier tube, the output signal from which was transmitted to the ground receiver.

Biomedical consequences of ozone depletion

NASA Astrophysics Data System (ADS)

Coohill, Thomas P.

1994-07-01

It is widely agreed that a portion of the earth's protective stratospheric ozone layer is being depleted. The major effect of this ozone loss will be an increase in the amount of ultraviolet radiation (UV reaching the biosphere. This increase will be completely contained within the UVB (290nm - 320nm). It is imperative that assessments be made of the effects of this additional UVB on living organisms. This requires a detailed knowledge of the UVB photobiology of these life forms. One analytical technique to aid in the approximations is the construction of UV action spectra for such important biological end-points as human skin cancer, cataracts, immune suppression; plant photosynthesis and crop yields; and aquatic organism responses to UVB, especially the phytoplankton. Combining these action spectra with the known solar spectrum (and estimates for various ozone depletion scenarios) can give rise to a series of effectiveness spectra for these parameters. This manuscript gives a first approximation, rough estimate, for the effectiveness spectra for some of these bioresponses, and a series of crude temporary values for how a 10% ozone loss would affect the above end-points. These are not intended to masquerade as final answers, but rather, to serve as beginning attempts for a process which should be continually refined. It is hoped that these estimates will be of some limited use to agencies, such as government and industry, that have to plan now for changes in human activities that might alter future atmospheric chemistry in a beneficial manner.

Advances in biologically inspired on/near sensor processing

NASA Astrophysics Data System (ADS)

McCarley, Paul L.

1999-07-01

As electro-optic sensors increase in size and frame rate, the data transfer and digital processing resource requirements also increase. In many missions, the spatial area of interest is but a small fraction of the available field of view. Choosing the right region of interest, however, is a challenge and still requires an enormous amount of downstream digital processing resources. In order to filter this ever-increasing amount of data, we look at how nature solves the problem. The Advanced Guidance Division of the Munitions Directorate, Air Force Research Laboratory at Elgin AFB, Florida, has been pursuing research in the are of advanced sensor and image processing concepts based on biologically inspired sensory information processing. A summary of two 'neuromorphic' processing efforts will be presented along with a seeker system concept utilizing this innovative technology. The Neuroseek program is developing a 256 X 256 2-color dual band IRFPA coupled to an optimized silicon CMOS read-out and processing integrated circuit that provides simultaneous full-frame imaging in MWIR/LWIR wavebands along with built-in biologically inspired sensor image processing functions. Concepts and requirements for future such efforts will also be discussed.

An observational study of the ozone dilution effect: Ozone transport in the austral spring stratosphere

NASA Technical Reports Server (NTRS)

Atkinson, Roger J.; Plumb, R. Alan

1994-01-01

In a previous observational analysis, Atkinson et al (1989) ascribed a sudden decrease in Southern Hemisphere midlatitude total ozone during December 1987 to an 'ozone dilution effect' brought about by the breakup of the polar stratospheric vortex at that time. A question alluded to but unanswered by that study was the degree to which the observed total ozone decrease might have been caused by the quasi-horizontal equatorward transport of 'ozone hold' air from within the vortex, and to what degree by the vertical advection from lower levels of air naturally low in ozone, a dynamical adjustment process which must accompany the equatorward outbreak of a discrete high-latitude airmass. In the present study, analyses of Ertel potential vorticity, TOMS total ozone, and SAGE and ozone sonde vertical profile data are employed using a novel technique to examine the 1987 event in greater detail, to answer this question. Recent progress is then reported in refining the technique and extending the investigation to examine the dynamical evolution of the austral spring stratosphere during other recent years, to shed more light on the precise nature, frequency, and severity of such 'ozone dilution' events, and the effect that this process may have on long term ozone behavior in the Southern Hemisphere.

Impact of Enhanced Ozone Deposition and Halogen Chemistry on Tropospheric Ozone over the Northern Hemisphere.

PubMed

Sarwar, Golam; Gantt, Brett; Schwede, Donna; Foley, Kristen; Mathur, Rohit; Saiz-Lopez, Alfonso

2015-08-04

Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen chemistry in a comprehensive atmospheric modeling system. The enhanced ozone deposition treatment accounts for the interaction of iodide in seawater with ozone and increases deposition velocities by 1 order of magnitude. Halogen chemistry includes detailed chemical reactions of organic and inorganic bromine and iodine species. Two different simulations are completed with the halogen chemistry: without and with photochemical reactions of higher iodine oxides. Enhanced deposition reduces mean summer-time surface ozone by ∼3% over marine regions in the Northern Hemisphere. Halogen chemistry without the photochemical reactions of higher iodine oxides reduces surface ozone by ∼15% whereas simulations with the photochemical reactions of higher iodine oxides indicate ozone reductions of ∼48%. The model without these processes overpredicts ozone compared to observations whereas the inclusion of these processes improves predictions. The inclusion of photochemical reactions for higher iodine oxides leads to ozone predictions that are lower than observations, underscoring the need for further refinement of the halogen emissions and chemistry scheme in the model.

Basic Ozone Layer Science

EPA Pesticide Factsheets

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.

Combined processes of ozonation and supercritical water oxidation for landfill leachate degradation.

PubMed

Scandelai, Ana Paula Jambers; Cardozo Filho, Lúcio; Martins, Danielly Cruz Campos; Freitas, Thabata Karoliny Formicoli de Souza; Garcia, Juliana Carla; Tavares, Célia Regina Granhen

2018-04-25

Leachate is a highly variable, heterogeneous and recalcitrant wastewater generated in landfills which may contain high concentrations of many organic and inorganic compounds, hampering the application of a single technique in its treatment. Therefore, this paper assessed leachate degradation through supercritical water oxidation (ScWO) as well as combined processes of ozonation and supercritical water oxidation (O 3 /ScWO and ScWO/O 3 ), a yet innovative combination. Ozonation was carried out at different reaction times (30-120 min). ScWO was developed at 600 °C, 23 MPa, and spatial time (τ) from 29 to 52 s. A combination of ozonation (30 min) and supercritical water oxidation process (O 3 -30'/ScWO) was the most efficient technique for the degradation of the leachate assessed. These conditions enabled to remove high values of apparent and true color (92% and 97%, respectively), biochemical oxygen demand (BOD 5,20 ) (95%), chemical oxygen demand (COD) (92%), total organic carbon (TOC) (79%), nitrite (78%), nitrate (84%), total (96%), dissolved (96%) and suspended (94%) solids. In addition, the combined process presented significant decrease in electric conductivity (EC) (68%) and less leachate turbidity removal (43%). Except for ammonia and nitrite, all parameters of the leachate treated by O 3 -30'/ScWO met the specifications of Brazilian legislation (CONAMA Resolutions No. 357/2005 and No. 430/2011) for the disposal of wastewater in water bodies. Besides, both processes are considered to be clean technologies. This shows the great possibility of applying the O 3 /ScWO combination to landfills leachates. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Tropospheric Ozone Assessment Report (TOAR): A community-wide effort to quantify tropospheric ozone in a rapidly changing world

NASA Astrophysics Data System (ADS)

Cooper, O. R.; Schultz, M.; Paoletti, E.; Galbally, I. E.; Naja, M. K.; Tarasick, D. W.; Evans, M. J.; Thompson, A. M.

2017-12-01

Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. Since 1990 a large portion of the anthropogenic emissions that react in the atmosphere to produce ozone has shifted from North America and Europe to Asia. This rapid shift, coupled with limited ozone monitoring in developing nations, left scientists unable to answer the most basic questions: Which regions of the world have the greatest human and plant exposure to ozone pollution? Is ozone continuing to decline in nations with strong emissions controls? To what extent is ozone increasing in the developing world? How can the atmospheric sciences community facilitate access to the ozone metrics necessary for quantifying ozone's impact on human health and crop/ecosystem productivity? To answer these questions the International Global Atmospheric Chemistry Project (IGAC) initiated the Tropospheric Ozone Assessment Report (TOAR). With over 220 member scientists and air quality specialists from 36 nations, TOAR's mission is to provide the research community with an up-to-date scientific assessment of tropospheric ozone's global distribution and trends from the surface to the tropopause. TOAR has also built the world's largest database of surface ozone observations and generated ozone exposure and dose metrics at thousands of measurement sites around the world, freely accessible for research on the global-scale impact of ozone on climate, human health and crop/ecosystem productivity. Plots of these metrics show the regions of the world with the greatest ozone exposure for humans and crops/ecosystems, at least in areas where observations are available. The results also highlight regions where air quality is improving and where it has degraded. TOAR has also conducted the first intercomparison of tropospheric column ozone from ozonesondes and multiple satellite instruments, which provide similar estimates of the present-day tropospheric ozone burden.

Modelling trends in tropical column ozone with the UKCA chemistry-climate model

NASA Astrophysics Data System (ADS)

Keeble, James; Bednarz, Ewa; Banerjee, Antara; Abraham, Luke; Harris, Neil; Maycock, Amanda; Pyle, John

2016-04-01

Trends in tropical column ozone under a number of different emissions scenarios are explored with the UM-UKCA coupled chemistry climate model. A transient 1960-2100 simulation was run following the RCP6 scenario. Tropical averaged (10S-10N) total column ozone values decrease from the 1970s, reaching a minimum around 2000, and return to their 1980 values around 2040, consistent with the use and emission of ozone depleting substances, and their later controls under the Montreal Protocol. However, when the total column is subdivided into three partial columns, extending from the surface to the tropopause, the tropopause to 30km, and 30km to 50km, significant differences to the total column trend are seen. Modelled tropospheric column values increase from 1960-2000 before remaining steady throughout the 21st Century. Lower stratospheric column values decrease rapidly from 1960-2000, remain steady until 2050 before slowly decreasing to 2100, never recovering to their 1980s values. Upper stratospheric values decrease from 1960-2000, before rapidly increasing throughout the 21st Century, recovering to 1980s values by ~2020 and are significantly increased above the 1980s values by 2100. Using a series of idealised model simulations with varying concentrations of greenhouse gases and ozone depleting substances, we assess the physical processes driving the partial column response in the troposphere, lower stratosphere and upper stratosphere, and assess how these processes change under different emissions scenarios. Finally, we present a simple, linearised model for predicting tropical column ozone values based on greenhouse gas and ozone depleting substance scenarios.

Present state of knowledge of the upper atmosphere: An assessment report; processes that control ozone and other climatically important trace gases

NASA Technical Reports Server (NTRS)

Watson, R. T.; Geller, M. A.; Stolarski, R. S.; Hampson, R. F.

1986-01-01

The state of knowledge of the upper atmosphere was assessed as of January 1986. The physical, chemical, and radiative processes which control the spatial and temporal distribution of ozone in the atmosphere; the predicted magnitude of ozone perturbations and climate changes for a variety of trace gas scenarios; and the ozone and temperature data used to detect the presence or absence of a long term trend were discussed. This assessment report was written by a small group of NASA scientists, was peer reviewed, and is based primarily on the comprehensive international assessment document entitled Atmospheric Ozone 1985: Assessment of Our Understanding of the Processes Controlling Its Present Distribution and Change, to be published as the World Meteorological Organization Global Ozone Research and Monitoring Project Report No. 16.

Clinical processes in behavioral couples therapy.

PubMed

Fischer, Daniel J; Fink, Brandi C

2014-03-01

Behavioral couples therapy is a broad term for couples therapies that use behavioral techniques based on principles of operant conditioning, such as reinforcement. Behavioral shaping and rehearsal and acceptance are clinical processes found across contemporary behavioral couples therapies. These clinical processes are useful for assessment and case formulation, as well as teaching couples new methods of conflict resolution. Although these clinical processes assist therapists in achieving efficient and effective therapeutic change with distressed couples by rapidly stemming couples' corrosive affective exchanges, they also address the thoughts, emotions, and issues of trust and intimacy that are important aspects of the human experience in the context of a couple. Vignettes are provided to illustrate the clinical processes described. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

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

PubMed

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.

Modeling vascular inflammation and atherogenicity after inhalation of ambient levels of ozone: exploratory lessons from transcriptomics.

PubMed

Tham, Andrea; Lullo, Dominic; Dalton, Sarah; Zeng, Siyang; van Koeverden, Ian; Arjomandi, Mehrdad

2017-02-01

Epidemiologic studies have linked inhalation of air pollutants such as ozone to cardiovascular mortality. Human exposure studies have shown that inhalation of ambient levels of ozone causes airway and systemic inflammation and an imbalance in sympathetic/parasympathetic tone. To explore molecular mechanisms through which ozone inhalation contributes to cardiovascular mortality, we compared transcriptomics data previously obtained from bronchoalveolar lavage (BAL) cells obtained from healthy subjects after inhalational exposure to ozone (200 ppb for 4 h) to those of various cell samples from 11 published studies of patients with atherosclerotic disease using the Nextbio genomic data platform. Overlapping gene ontologies that may be involved in the transition from pulmonary to systemic vascular inflammation after ozone inhalation were explored. Local and systemic enzymatic activity of an overlapping upregulated gene, matrix metalloproteinase-9 (MMP-9), was measured by zymography after ozone exposure. A set of differentially expressed genes involved in response to stimulus, stress, and wounding were in common between the ozone and most of the atherosclerosis studies. Many of these genes contribute to biological processes such as cholesterol metabolism dysfunction, increased monocyte adherence, endothelial cell lesions, and matrix remodeling, and to diseases such as heart failure, ischemia, and atherosclerotic occlusive disease. Inhalation of ozone increased MMP-9 enzymatic activity in both BAL fluid and serum. Comparison of transcriptomics between BAL cells after ozone exposure and various cell types from patients with atherosclerotic disease reveals commonly regulated processes and potential mechanisms by which ozone inhalation may contribute to progression of pre-existent atherosclerotic lesions.

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

NASA Astrophysics Data System (ADS)

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

2008-12-01

Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling research. The nations of the world implemented the Montreal Protocol (and amendments) which stopped ODS production in 1992. In this presentation we use a fully coupled radiation- chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally average column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Ozone, Tropospheric

NASA Technical Reports Server (NTRS)

Fishman, Jack

1995-01-01

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

Mechanisms of inactivation of bacteriophage phiX174 and its DNA in aerosols by ozone and ozonized cyclohexene.

PubMed Central

de Mik, G.; de Groot, I.

1977-01-01

The mechanisms of inactivation of aerosolized bacteriophage phiX174 in atmospheres containing ozone, cyclohexene, or ozonized cyclohexene were studied by using 32P-labelled phage. The inactivation of the aerosolized phage in clear air or in air containing cyclohexene is due to damage of the protein coat since the deoxyribonucleic acid (DNA) extracted from the inactivated phage retains its biological activity. Inactivation of the phage in air containing ozonized cyclohexene is due both to protein and DNA damage. Sucrose gradient analysis shows that aerosolized inactivated phiX174 releases unbroken DNA. In contrast, the DNA from phage phiX174 inactivated by ozonized cyclohexene is broken. The inactivation of aerosolized phage phiX174-DNA was studied in the same atmospheres using 32P-labelled DNA. phiX174-DNA aerosolized in clear air or air containing cyclohexene at 75% r.h. is inactivated by a factor of 2 in 30 min. The inactivated DNA is broken. Ozone as well as ozonized cyclohexene inactivates KNA very fast causing breaks in the molecule. This is in contrast with the intact bacteriophage in which ozone does not produce breaks in the DNA. PMID:265342

Recovery of the Antarctic Ozone Hole

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve; Schauffler, Sue; Stolarski, Richard S.; Douglass, Anne R.; Pawson, Steven; Nielsen, J. Eric

2006-01-01

The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS and OMI instruments. The severity of the hole has been assessed using the minimum total ozone value from the October monthly mean (depth of the hole), the average size during the September-October period, and the ozone mass deficit. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. We use two methods to estimate ozone hole recovery. First, we use projections of halogen levels combined with age-of-air estimates in a parametric model. Second, we use a coupled chemistry climate model to assess recovery. We find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. Furthermore, full recovery to 1980 levels will not occur until approximately 2068. We will also show some error estimates of these dates and the impact of climate change on the recovery.

Impact of synoptic controls and boundary layer processes on ground-level ozone evolution at an urban site

NASA Astrophysics Data System (ADS)

Haman, Christine Lanier

Houston, Texas frequently exceeds the standard for ground-level ozone during the spring and fall. The large commuting population and vast number of industrial sources provide the necessary ingredients for photochemical ozone production in the presence of favorable meteorological conditions. The lack of continuous boundary layer (BL) observations prevents a comprehensive understanding of its role in ozone evolution. In this study, almost two years of BL observations are utilized to investigate the impacts of synoptic and micrometeorological-scale forcings on ozone. Aerosol gradients derived from ceilometer backscatter retrievals are used to identify the BL and residual layers (RL). Overall agreement is found between ceilometer and sonde estimates of the RL and BL heights (BLH), but difficulty detecting the layers occurs during cloud periods or immediately following precipitation. Large monthly variability is present in the peak afternoon BLH (e.g. mean August and December peaks are ˜2000 and 1100 m, respectively). Monthly nocturnal BLHs display much smaller differences. The majority of ozone exceedances occur during large-scale subsidence and weak winds in a postfrontal environment. These conditions result in turbulent kinetic energy, mechanical mixing, and ventilation processes that are 2--3 times weaker on exceedance days, which inhibit morning BL growth by an average of ˜100 m·hr-1 compared to low ozone days. The spring has higher nocturnal ozone levels, which is likely attributable to longer day lengths (˜78 minutes), stronger winds (˜0.78 m·s -1), and higher background ozone (˜5 ppbv) compared to the fall. Boundary layer entrainment plays an important role in ozone evolution. Exceedance days show a characteristic early morning rapid rise of ozone. Vertical ozone profiles indicate the RL ozone peak is ˜60 ppbv on exceedance days, which is ˜25 ppbv (+/- 10 ppbv) greater than low ozone days. The Integrated Profile Mixing (IPM) and Photochemical Budget (PB

The Ozone Budget in the Upper Troposphere from Global Modeling Initiative (GMI)Simulations

NASA Technical Reports Server (NTRS)

Rodriquez, J.; Duncan, Bryan N.; Logan, Jennifer A.

2006-01-01

Ozone concentrations in the upper troposphere are influenced by in-situ production, long-range tropospheric transport, and influx of stratospheric ozone, as well as by photochemical removal. Since ozone is an important greenhouse gas in this region, it is particularly important to understand how it will respond to changes in anthropogenic emissions and changes in stratospheric ozone fluxes.. This response will be determined by the relative balance of the different production, loss and transport processes. Ozone concentrations calculated by models will differ depending on the adopted meteorological fields, their chemical scheme, anthropogenic emissions, and treatment of the stratospheric influx. We performed simulations using the chemical-transport model from the Global Modeling Initiative (GMI) with meteorological fields from (It)h e NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM), (2) the atmospheric GCM from NASA's Global Modeling and Assimilation Office(GMAO), and (3) assimilated winds from GMAO . These simulations adopt the same chemical mechanism and emissions, and adopt the Synthetic Ozone (SYNOZ) approach for treating the influx of stratospheric ozone -. In addition, we also performed simulations for a coupled troposphere-stratosphere model with a subset of the same winds. Simulations were done for both 4degx5deg and 2degx2.5deg resolution. Model results are being tested through comparison with a suite of atmospheric observations. In this presentation, we diagnose the ozone budget in the upper troposphere utilizing the suite of GMI simulations, to address the sensitivity of this budget to: a) the different meteorological fields used; b) the adoption of the SYNOZ boundary condition versus inclusion of a full stratosphere; c) model horizontal resolution. Model results are compared to observations to determine biases in particular simulations; by examining these comparisons in conjunction with the derived budgets, we may pinpoint

New Insights in Tropospheric Ozone and its Variability

NASA Technical Reports Server (NTRS)

Oman, Luke D.; Douglass, Anne R.; Ziemke, Jerry R.; Rodriquez, Jose M.

2011-01-01

We have produced time-slice simulations using the Goddard Earth Observing System Version 5 (GEOS-5) coupled to a comprehensive stratospheric and tropospheric chemical mechanism. These simulations are forced with observed sea surface temperatures over the past 25 years and use constant specified surface emissions, thereby providing a measure of the dynamically controlled ozone response. We examine the model performance in simulating tropospheric ozone and its variability. Here we show targeted comparisons results from our simulations with a multi-decadal tropical tropospheric column ozone dataset obtained from satellite observations of total column ozone. We use SHADOZ ozonesondes to gain insight into the observed vertical response and compare with the simulated vertical structure. This work includes but is not limited to ENSO related variability.

Interactive coupling of electronic and optical man-made devices to biological systems

NASA Astrophysics Data System (ADS)

Ozden, Ilker

Fireflies blink synchronously, lasers are "mode-locked" for amplification, cardiac pacemaker cells maintain a steady heartbeat, and crickets chirps get in step. These are examples of coupled oscillators. Coupled non-linear limit-cycle oscillator models are used extensively to provide information about the collective behavior of many physical and biological systems. Depending on the system parameters, namely, the coupling coefficient and the time delay in the coupling, these coupled limit-cycle oscillator exhibit several interesting phenomena; they either synchronize to a common frequency, or oscillate completely independent of each other, or drag each other to a standstill i.e., show "amplitude death". Many neuronal systems exhibit synchronized limit-cycle oscillations in network of electrically coupled cells. The inferior olivary (IO) neuron is an example of such a system. The inferior olive has been widely studied by neuroscientists as it exhibits spontaneous oscillations in its membrane potential, typically in the range of 1--10 Hz. Located in the medulla, the inferior olive is believed to form the neural basis for precise timing and learning in motor circuits by making strong synaptic connections onto Purkinjee cells in the cerebellum. In this thesis work, we report on work, which focuses on the implementation and study of coupling of a biological circuit, which is the inferior olivary system, with a man-made electronic oscillator, the so-called Chua's circuit. We were able to study the interaction between the two oscillators over a wide range coupling conditions. With increasing coupling strength, the oscillators become phase-locked, or synchronized, but with a phase relationship which is either in- or out-of-phase depending on the detailed adjustment in the coupling. Finally, the coupled system reaches the conditions for amplitude death, a rather fundamental result given that the interaction has taken place between purely biological and man-made circuit

Remedial Process Optimization and Green In-Situ Ozone Sparging for Treatment of Groundwater Impacted with Petroleum Hydrocarbons

NASA Astrophysics Data System (ADS)

Leu, J.

2012-12-01

A former natural gas processing station is impacted with TPH and BTEX in groundwater. Air sparging and soil vapor extraction (AS/AVE) remediation systems had previously been operated at the site. Currently, a groundwater extraction and treatment system is operated to remove the chemicals of concern (COC) and contain the groundwater plume from migrating offsite. A remedial process optimization (RPO) was conducted to evaluate the effectiveness of historic and current remedial activities and recommend an approach to optimize the remedial activities. The RPO concluded that both the AS/SVE system and the groundwater extraction system have reached the practical limits of COC mass removal and COC concentration reduction. The RPO recommended an in-situ chemical oxidation (ISCO) study to evaluate the best ISCO oxidant and approach. An ISCO bench test was conducted to evaluate COC removal efficiency and secondary impacts to recommend an application dosage. Ozone was selected among four oxidants based on implementability, effectiveness, safety, and media impacts. The bench test concluded that ozone demand was 8 to 12 mg ozone/mg TPH and secondary groundwater by-products of ISCO include hexavalent chromium and bromate. The pH also increased moderately during ozone sparging and the TDS increased by approximately 20% after 48 hours of ozone treatment. Prior to the ISCO pilot study, a capture zone analysis (CZA) was conducted to ensure containment of the injected oxidant within the existing groundwater extraction system. The CZA was conducted through a groundwater flow modeling using MODFLOW. The model indicated that 85%, 90%, and 95% of an injected oxidant could be captured when a well pair is injecting and extracting at 2, 5, and 10 gallons per minute, respectively. An ISCO pilot test using ozone was conducted to evaluate operation parameters for ozone delivery. The ozone sparging system consisted of an ozone generator capable of delivering 6 lbs/day ozone through two ozone

Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Villalta, Peter W.; Zahniser, Mark S.; Nelson, David D.; Kolb, Charles E.

1997-01-01

The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(x) and NO(x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. The second year's effort has focussed the design and construction of the proposed high pressure flow reactor on three separate areas: (1) the construction of the high pressure flow reactor; (2) characterization of the turbulent flow profile; and (3) demonstration of the instrument by measuring HO2 + NO2 and HO2 + NO reaction rate coefficients.

Ozone bioindicator sampling and estimation

Treesearch

Gretchen C, Smith; William D. Smith; John W. Coulston

2007-01-01

Ozone is an important forest stressor that has been measured at known phytotoxic levels at forest locations across the United States. The percent forest exhibiting negative impacts from ozone air pollution is one of the Montreal Process indicators of forest health and vitality. The ozone bioindicator data of the U.S. Forest Service Forest Inventory and Analysis Program...

Present-day distribution and trends of global tropospheric ozone from satellite observations: Results from the Tropospheric Ozone Assessment Report (TOAR)

NASA Astrophysics Data System (ADS)

Gaudel, A.; Cooper, O. R.; Barret, B.; Boynard, A.; Clerbaux, C.; Pierre-Francois, C.; Huang, G.; Hurtmans, D.; Kerridge, B. J.; Latter, B.; Le Flochmoen, E.; Liu, X.; Neu, J. L.; Siddans, R.; Wespes, C.; Worden, H. M.; Ziemke, J. R.

2017-12-01

Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. Since 1990 a large portion of the anthropogenic emissions that react in the atmosphere to produce ozone have shifted from North America and Europe to Asia. This rapid shift, coupled with limited ozone monitoring in developing nations, has left scientists unable to answer the most basic questions: Is ozone continuing to decline in nations with strong emission controls? To what extent is ozone increasing in the developing world? IGAC's Tropospheric Ozone Assessment Report (TOAR) has been designed to answer these questions and this presentation will show the results from the TOAR-Climate initiative, focusing on the present-day distribution and trends of global tropospheric ozone from satellite observations. Five satellite products based on OMI (2 products using two different retrieval methods) and IASI (also 2 products using two different retrieval methods) and the OMI/MLS combined product were intercompared. An important result is the close agreement among the five products regarding the quantification of the total mass of all tropospheric ozone, the so called tropospheric ozone burden (TOB). The mean estimate for TOB between 60° N and 60° S is 296 Tg, with all products agreeing within ± 4%. However, on a regional basis the five satellite products have notable differences and there is no agreement in terms of ozone trends over the past decade. Continuing work is exploring the causes of these differences.

Impact of ozonation on naphthenic acids speciation and toxicity of oil sands process-affected water to Vibrio fischeri and mammalian immune system.

PubMed

Wang, Nan; Chelme-Ayala, Pamela; Perez-Estrada, Leonidas; Garcia-Garcia, Erick; Pun, Jonathan; Martin, Jonathan W; Belosevic, Miodrag; Gamal El-Din, Mohamed

2013-06-18

Oil sands process-affected water (OSPW) is the water contained in tailings impoundment structures in oil sands operations. There are concerns about the environmental impacts of the release of OSPW because of its toxicity. In this study, ozonation followed by biodegradation was used to remediate OSPW. The impacts of the ozone process evolution on the naphthenic acids (NAs) speciation and acute toxicity were evaluated. Ion-mobility spectrometry (IMS) was used to preliminarily separate isomeric and homologous species. The results showed limited effects of the ozone reactor size on the treatment performance in terms of contaminant removal. In terms of NAs speciation, high reactivity of NAs with higher number of carbons and rings was only observed in a region of high reactivity (i.e., utilized ozone dose lower than 50 mg/L). It was also found that nearly 0.5 mg/L total NAs was oxidized per mg/L of utilized ozone dose, at utilized ozone doses lower than 50 mg/L. IMS showed that ozonation was able to degrade NAs, oxidized NAs, and sulfur/nitrogenated NAs. Complete removal of toxicity toward Vibrio fischeri was achieved after ozonation followed by 28-day biodegradation period. In vitro and in vivo assays indicated that ozonation reduced the OSPW toxicity to mice.

Chemical processes related to net ozone tendencies in the free troposphere

NASA Astrophysics Data System (ADS)

Bozem, Heiko; Butler, Tim M.; Lawrence, Mark G.; Harder, Hartwig; Martinez, Monica; Kubistin, Dagmar; Lelieveld, Jos; Fischer, Horst

2017-09-01

Ozone (O3) is an important atmospheric oxidant, a greenhouse gas, and a hazard to human health and agriculture. Here we describe airborne in situ measurements and model simulations of O3 and its precursors during tropical and extratropical field campaigns over South America and Europe, respectively. Using the measurements, net ozone formation/destruction tendencies are calculated and compared to 3-D chemistry-transport model simulations. In general, observation-based net ozone tendencies are positive in the continental boundary layer and the upper troposphere at altitudes above ˜ 6 km in both environments. On the other hand, in the marine boundary layer and the middle troposphere, from the top of the boundary layer to about 6-8 km altitude, net O3 destruction prevails. The ozone tendencies are controlled by ambient concentrations of nitrogen oxides (NOx). In regions with net ozone destruction the available NOx is below the threshold value at which production and destruction of O3 balance. While threshold NO values increase with altitude, in the upper troposphere NOx concentrations are generally higher due to the integral effect of convective precursor transport from the boundary layer, downward transport from the stratosphere and NOx produced by lightning. Two case studies indicate that in fresh convective outflow of electrified thunderstorms net ozone production is enhanced by a factor 5-6 compared to the undisturbed upper tropospheric background. The chemistry-transport model MATCH-MPIC generally reproduces the pattern of observation-based net ozone tendencies but mostly underestimates the magnitude of the net tendency (for both net ozone production and destruction).

An Extended View of Mars Ozone

NASA Technical Reports Server (NTRS)

Fast, Kelly

2011-01-01

We present an ongoing effort to characterize chemistry in Mars' atmosphere in multiple seasons on timescales longer than flight missions through coordinated efforts by GSFC's HIPWAC spectrometer and Mars Express SPICAM, archival measurements, and tests/application of photochemical models. The trace species ozone (O3) is an effective probe of atmospheric chemistry because it is destroyed by chemically active odd hydrogen species (HO(sub x)) that result from water vapor photolysis. Observed ozone abundance on Mars is a critical test for three-dimensional photochemistry coupled general circulation models (GCM) that make specific predictions for the spatial, diurnal, and seasonal behavior of ozone and related chemistry and climatological conditions. Coordinated measurements by HIPWAC and SPICAM quantitatively linked mission data to the 23-year GSFC ozone data record and also revealed unanticipated inter-decadal variability of same-season ozone abundances, a possible indicator of changing cloud activity (heterogeneous sink for HO(sub x)). A detailed study of long-term conditions is critical to characterizing the predictability of Mars' seasonal chemical behavior, particularly in light of the implications of and the lack of explanation for reported methane behavior.

Ground-Level Ozone Following Astrophysical Ionizing Radiation Events: An Additional Biological Hazard?

PubMed

Thomas, Brian C; Goracke, Byron D

2016-01-01

Astrophysical ionizing radiation events such as supernovae, gamma-ray bursts, and solar proton events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in solar UV radiation at Earth's surface and in the upper levels of the ocean. Other work has also considered the potential impact of nitric acid rainout, concluding that no significant threat is likely. Not yet studied to date is the potential impact of ozone produced in the lower atmosphere following an ionizing radiation event. Ozone is a known irritant to organisms on land and in water and therefore may be a significant additional hazard. Using previously completed atmospheric chemistry modeling, we examined the amount of ozone produced in the lower atmosphere for the case of a gamma-ray burst and found that the values are too small to pose a significant additional threat to the biosphere. These results may be extended to other ionizing radiation events, including supernovae and extreme solar proton events.

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

NASA Technical Reports Server (NTRS)

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

Decomposition of gas-phase trichloroethene by the UV/TiO2 process in the presence of ozone.

PubMed

Shen, Y S; Ku, Y

2002-01-01

The decomposition of gas-phase trichloroethene (TCE) in air streams by direct photolysis, the UV/TiO2 and UV/O3 processes was studied. The experiments were carried out under various UV light intensities and wavelengths, ozone dosages, and initial concentrations of TCE to investigate and compare the removal efficiency of the pollutant. For UV/TiO2 process, the individual contribution to the decomposition of TCE by direct photolysis and hydroxyl radicals destruction was differentiated to discuss the quantum efficiency with 254 and 365 nm UV lamps. The removal of gaseous TCE was found to reduce by UV/TiO2 process in the presence of ozone possibly because of the ozone molecules could scavenge hydroxyl radicals produced from the excitation of TiO2 by UV radiation to inhibit the decomposition of TCE. A photoreactor design equation for the decomposition of gaseous TCE by the UV/TiO2 process in air streams was developed by combining the continuity equation of the pollutant and the surface catalysis reaction rate expression. By the proposed design scheme, the temporal distribution of TCE at various operation conditions by the UV/TiO2 process can be well modeled.

Future changes in tropospheric ozone under Representative Concentration Pathways (RCPs)

NASA Astrophysics Data System (ADS)

Kawase, Hiroaki; Nagashima, Tatsuya; Sudo, Kengo; Nozawa, Toru

2011-03-01

We consider future changes in tropospheric ozone based on the Representative Concentration Pathways (RCPs), which are new emission and concentration scenarios for the 5th coupled model intercomparison project. In contrast to the SRES scenarios, all the RCP scenarios assume an emission reduction of NOx by the late 21st Century that has the potential to achieve tropospheric ozone reduction. However, increasing radiative forcing (RF) due to greenhouse gases and changes in CH4 concentration also contribute to differences in the tropospheric ozone distribution among RCP scenarios. In the RCP4.5 and RCP6.0, assuming the stabilization of RF, the increase in tropospheric ozone due to enhanced residual circulation is cancelled out by the ozone reduction due to ozone precursor reductions. In contrast, in the RCP8.5, assuming increasing RF even after 2100, further enhanced residual circulation and significant increase in CH4 cause a dramatic increase in tropospheric ozone.

HYDROXYL RADICAL/OZONE RATIOS DURING OZONATION PROCESSES. II. THE EFFECT OF TEMPERATURE, PH, ALKALINITY, AND DOM PROPERTIES

EPA Science Inventory

The influence of temperature, pH, alkalinity, and type and concentration of the dissolved organic matter (DOM) on the rate of ozone (O3) decomposition, O3-exposure, .OH-exposure and the ratio Rct of the concentrations of .OH and O3 has been studied. For a standardized single ozon...

Evaluation of the potential of ozone as a power plant biocide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattice, J.S.; Trabalka, J.R.; Adams, S.M.

1978-09-01

A review of the literature on the chemistry and biological effects of ozone was conducted to evaluate the potential of ozone to function as a power plant biocide. Evaluation of this potential is dependent upon determining the ability of ozone to maintain the integrity of both the condenser cooling system and the associated ecosystem. The well-known bactericidal capacity of ozone and the limited biofouling control studies conducted thus far suggest that ozone can control both slime and macroinvertebrate fouling at power plants. However, full-scale demonstrations of the minimum levels of ozone required and of solution of the practical aspects ofmore » application have not been performed.« less

Fouling reduction by ozone-enhanced backwashing process in ultrafiltration of petroleum-based oil in water emulsion

NASA Astrophysics Data System (ADS)

Aryanti, Nita; Prihatiningtyas, Indah; Kusworo, Tutuk Djoko

2017-06-01

Ultrafiltration membrane has been successfully applied for oily waste water treatment. However, one significant drawback of membrane technology is fouling which is responsible for permeate flux decline as well as reducing membrane performance. One method commonly used to reduce fouling is a backwashing process. The backwashing is carried out by a push of reversed flow from permeate side to the feed side of a membrane to remove fouling on the membrane pore and release fouling release fouling layer on the external side. However, for adsorptive fouling, the backwashing process was not effective. On the other hand, Ozone demonstrated great performance for reducing organics fouling. Hence this research was focused on backwashing process with ozone for removing fouling due to ultrafiltration of petroleum based oil emulsion. Gasoline and diesel oil were selected as dispersed phase, while as continuous phase was water added with Tween 80 as a surfactant. This research found that the Ozone backwashing was effective to improve flux recovery. In ultrafiltration of gasoline emulsion, the flux recovery after Ozone backwashing was in the range of 42-74%. For ultrafiltration of diesel oil emulsion, the permeate flux recovery was about 35-84%. In addition, foulant deposition was proposed and predicting that foulant deposition for ultrafiltration of gasoline-in-water emulsion was surfactant as the top layer and the oil was underneath the surfactant. On the other hand, for ultrafiltration of diesel oil-in-water emulsion, the oil was predicted as a top layer above the surfactant foulant.

Ozone pretreatment and fermentative hydrolysis of wheat straw

NASA Astrophysics Data System (ADS)

Ben'ko, E. M.; Chukhchin, D. G.; Lunin, V. V.

2017-11-01

Principles of the ozone pretreatment of wheat straw for subsequent fermentation into sugars are investigated. The optimum moisture contents of straw in the ozonation process are obtained from data on the kinetics of ozone absorbed by samples with different contents of water. The dependence of the yield of reducing sugars in the fermentative reaction on the quantity of absorbed ozone is established. The maximum conversion of polysaccharides is obtained at ozone doses of around 3 mmol/g of biomass, and it exceeds the value for nonozonated samples by an order of magnitude. The yield of sugar falls upon increasing the dose of ozone. The process of removing lignin from the cell walls of straw during ozonation is visualized by means of scanning electron microscopy.

Medium-high frequency ultrasound and ozone based advanced oxidation for amoxicillin removal in water.

PubMed

Kıdak, Rana; Doğan, Şifa

2018-01-01

In this study, treatment of an antibiotic compound amoxicillin by medium-high frequency ultrasonic irradiation and/or ozonation has been studied. Ultrasonic irradiation process was carried out in a batch reactor for aqueous amoxicillin solutions at three different frequencies (575, 861 and 1141kHz). The applied ultrasonic power was 75W and the diffused power was calculated as 14.6W/L. The highest removal was achieved at 575kHz ultrasonic frequency (>99%) with the highest pseudo first order reaction rate constant 0.04min -1 at pH 10 but the mineralization achieved was around 10%. Presence of alkalinity and humic acid species had negative effect on the removal efficiency (50% decrease). To improve the poor outcomes, ozonation had been applied with or without ultrasound. Ozone removed the amoxicillin at a rate 50 times faster than ultrasound. Moreover, due to the synergistic effect, coupling of ozone and ultrasound gave rise to rate constant of 2.5min -1 (625 times higher than ultrasound). In the processes where ozone was used, humic acid did not show any significant effect because the rate constant was so high that ozone has easily overcome the scavenging effects of natural water constituents. Furthermore, the intermediate compounds, after the incomplete oxidation mechanisms, has been analyzed to reveal the possible degradation pathways of amoxicillin through ultrasonic irradiation and ozonation applications. The outcomes of the intermediate compounds experiments and the toxicity was investigated to give a clear explanation about the safety of the resulting solution. The relevance of all the results concluded that hybrid advanced oxidation system was the best option for amoxicillin removal. Copyright © 2017 Elsevier B.V. All rights reserved.

Ozone Depletion from Nearby Supernovae

NASA Technical Reports Server (NTRS)

Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

2002-01-01

Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

Ozone response to enhanced heterogeneous processing after the eruption of Mt. Pinatubo

NASA Technical Reports Server (NTRS)

Rodriguez, Jose M.; Ko, M. K. W.; Sze, N. D.; Heisey, C. W.; Yue, G. K.; Mccormick, M. P.

1994-01-01

Increases in aerosol loading after the Pinatubo eruption are expected to cause additional ozone depletion. Even though aerosol loadings were highest in the winter of 1991-1992, recent analyses of satellite and ground-based ozone measurements indicate that ozone levels in the winter of 1992-1993 are the lowest recorded in recent years, raising the question of the mechanisms responsible for such behavior. We have incorporated aerosol surface areas derived from the Stratospheric Aerosol and Gas Experiment II (SAGE-II) measurements into our two-dimensional model. Inclusion of heterogeneous chemsitry on these enhanced aerosol surfaces yields maximum ozone reductions during the winter of 1992-1993 in the Northern Hemisphere, consistent with those derived from observations. This delayed behavior is due to the combination of the non-linear nature of the impact of heterogeneous reactions as a function of aerosol surface area, and the long time constants for ozone in the lower stratosphere. If heterogeneous mechanisms are primarily responsible for the low 1992-1993 ozone levels, we expect ozone concentrations to start recovering in 1994.

Factors dominating 3-dimensional ozone distribution during high tropospheric ozone period.

PubMed

Chen, Xiaoyang; Liu, Yiming; Lai, Anqi; Han, Shuangshuang; Fan, Qi; Wang, Xuemei; Ling, Zhenhao; Huang, Fuxiang; Fan, Shaojia

2018-01-01

Data from an in situ monitoring network and five ozone sondes are analysed during August of 2012, and a high tropospheric ozone episode is observed around the 8th of AUG. The Community Multi-scale Air Quality (CMAQ) model and its process analysis tool were used to study factors and mechanisms for high ozone mixing ratio at different levels of ozone vertical profiles. A sensitive scenario without chemical initial and boundary conditions (ICBCs) from MOZART4-GEOS5 was applied to study the impact of stratosphere-troposphere exchange (STE) on vertical ozone. The simulation results indicated that the first high ozone peak near the tropopause was dominated by STE. Results from process analysis showed that: in the urban area, the second peak at approximately 2 km above ground height was mainly caused by local photochemical production. The third peak (near surface) was mainly caused by the upwind transportation from the suburban/rural areas; in the suburban/rural areas, local photochemical production of ozone dominated the high ozone mixing ratio from the surface to approximately 3 km height. Furthermore, the capability of indicators to distinguish O 3 -precursor sensitivity along the vertical O 3 profiles was investigated. Two sensitive scenarios, which had cut 30% anthropogenic NO X or VOC emissions, showed that O 3 -precursor indicators, specifically the ratios of O 3 /NOy, H 2 O 2 /HNO 3 or H 2 O 2 /NO Z , could partly distinguish the O 3 -precursor sensitivity between VOCs-sensitive and NOx-sensitive along the vertical profiles. In urban area, the O 3 -precursor relationship transferred from VOCs-sensitive within the boundary layer to NOx-sensitive at approximately 1-3 km above ground height, further confirming the dominant roles of transportation and photochemical production in high O 3 peaks at the near-ground layer and 2 km above ground height, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

An extreme anomaly in stratospheric ozone over Europe in 1940-1942

NASA Astrophysics Data System (ADS)

Brönnimann, S.; Luterbacher, J.; Staehelin, J.; Svendby, T. M.

2004-04-01

Reevaluated historical total ozone data reveal extraordinarily high values over several European sites in 1940-1942, concurrent with extreme climatic anomalies at the Earth's surface. Using historical radiosonde data, reconstructed upper-level fields, and total ozone data from Arosa (Switzerland), Dombås, and Tromsø (Norway), this unusual case of stratosphere-troposphere coupling is analyzed. At Arosa, numerous strong total ozone peaks in all seasons were due to unusually frequent upper troughs over central Europe and related ozone redistribution in the lower stratosphere. At the Norwegian sites, high winter total ozone was most likely caused by major stratospheric warmings in Jan./Feb. 1940, Feb./Mar. 1941, and Feb. 1942. Results demonstrate that the dynamically driven interannual variability of total ozone can be much larger than that estimated based on the past 25-40 years.

Ozone Gas as a Benign Sterilization Treatment for PLGA Nanofiber Scaffolds

PubMed Central

de Jesus Andreoli Pinto, Terezinha; Bou-Chacra, Nadia Araci; Galante, Raquel; de Araújo, Gabriel Lima Barros; do Nascimento Pedrosa, Tatiana; Maria-Engler, Silvya Stuchi

2016-01-01

The use of electrospun nanofibers for tissue engineering and regenerative medicine applications is a growing trend as they provide improved support for cell proliferation and survival due, in part, to their morphology mimicking that of the extracellular matrix. Sterilization is a critical step in the fabrication process of implantable biomaterial scaffolds for clinical use, but many of the existing methods used to date can negatively affect scaffold properties and performance. Poly(lactic-co-glycolic acid) (PLGA) has been widely used as a biodegradable polymer for 3D scaffolds and can be significantly affected by current sterilization techniques. The aim of this study was to investigate pulsed ozone gas as an alternative method for sterilizing PLGA nanofibers. The morphology, mechanical properties, physicochemical properties, and response of cells to PLGA nanofiber scaffolds were assessed following different degrees of ozone gas sterilization. This treatment killed Geobacillus stearothermophilus spores, the most common biological indicator used for validation of sterilization processes. In addition, the method preserved all of the characteristics of nonsterilized PLGA nanofibers at all degrees of sterilization tested. These findings suggest that ozone gas can be applied as an alternative method for sterilizing electrospun PLGA nanofiber scaffolds without detrimental effects. PMID:26757850

Ozone Gas as a Benign Sterilization Treatment for PLGA Nanofiber Scaffolds.

PubMed

Rediguieri, Carolina Fracalossi; Pinto, Terezinha de Jesus Andreoli; Bou-Chacra, Nadia Araci; Galante, Raquel; de Araújo, Gabriel Lima Barros; Pedrosa, Tatiana do Nascimento; Maria-Engler, Silvya Stuchi; De Bank, Paul A

2016-04-01

The use of electrospun nanofibers for tissue engineering and regenerative medicine applications is a growing trend as they provide improved support for cell proliferation and survival due, in part, to their morphology mimicking that of the extracellular matrix. Sterilization is a critical step in the fabrication process of implantable biomaterial scaffolds for clinical use, but many of the existing methods used to date can negatively affect scaffold properties and performance. Poly(lactic-co-glycolic acid) (PLGA) has been widely used as a biodegradable polymer for 3D scaffolds and can be significantly affected by current sterilization techniques. The aim of this study was to investigate pulsed ozone gas as an alternative method for sterilizing PLGA nanofibers. The morphology, mechanical properties, physicochemical properties, and response of cells to PLGA nanofiber scaffolds were assessed following different degrees of ozone gas sterilization. This treatment killed Geobacillus stearothermophilus spores, the most common biological indicator used for validation of sterilization processes. In addition, the method preserved all of the characteristics of nonsterilized PLGA nanofibers at all degrees of sterilization tested. These findings suggest that ozone gas can be applied as an alternative method for sterilizing electrospun PLGA nanofiber scaffolds without detrimental effects.

Forests and ozone: productivity, carbon storage, and feedbacks.

PubMed

Wang, Bin; Shugart, Herman H; Shuman, Jacquelyn K; Lerdau, Manuel T

2016-02-22

Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution.

The Use of Regulatory Air Quality Models to Develop Successful Ozone Attainment Strategies

NASA Astrophysics Data System (ADS)

Canty, T. P.; Salawitch, R. J.; Dickerson, R. R.; Ring, A.; Goldberg, D. L.; He, H.; Anderson, D. C.; Vinciguerra, T.

2015-12-01

The Environmental Protection Agency (EPA) recently proposed lowering the 8-hr ozone standard to between 65-70 ppb. Not all regions of the U.S. are in attainment of the current 75 ppb standard and it is expected that many regions currently in attainment will not meet the future, lower surface ozone standard. Ozone production is a nonlinear function of emissions, biological processes, and weather. Federal and state agencies rely on regulatory air quality models such as the Community Multi-Scale Air Quality (CMAQ) model and Comprehensive Air Quality Model with Extensions (CAMx) to test ozone precursor emission reduction strategies that will bring states into compliance with the National Ambient Air Quality Standards (NAAQS). We will describe various model scenarios that simulate how future limits on emission of ozone precursors (i.e. NOx and VOCs) from sources such as power plants and vehicles will affect air quality. These scenarios are currently being developed by states required to submit a State Implementation Plan to the EPA. Projections from these future case scenarios suggest that strategies intended to control local ozone may also bring upwind states into attainment of the new NAAQS. Ground based, aircraft, and satellite observations are used to ensure that air quality models accurately represent photochemical processes within the troposphere. We will highlight some of the improvements made to the CMAQ and CAMx model framework based on our analysis of NASA observations obtained by the OMI instrument on the Aura satellite and by the DISCOVER-AQ field campaign.

Coping Processes of Couples Experiencing Infertility

ERIC Educational Resources Information Center

Peterson, Brennan D.; Newton, Christopher R.; Rosen, Karen H.; Schulman, Robert S.

2006-01-01

This study explored the coping processes of couples experiencing infertility. Participants included 420 couples referred for advanced reproductive treatments. Couples were divided into groups based on the frequency of their use of eight coping strategies. Findings suggest that coping processes, which are beneficial to individuals, may be…

Tropospheric Ozone Over North America

NASA Astrophysics Data System (ADS)

Oltmans, S. J.; Thompson, A. M.; Cooper, O. R.; Merrill, J. T.; Tarasick, D. W.; Newchurch, M. J.

2007-05-01

Ozone in the troposphere plays a significant role as an absorber of infrared radiation (greenhouse gas), in the cleansing capacity of the atmosphere as a precursor of hydroxol radical formation, and a regulated air pollutant capable of deleterious health and ecosystem effects. Knowledge of the ozone budget in the troposphere over North America (NA) is required to properly understand the various mechanisms that contribute to the measured distribution and to develop and test models capable of simulating and predicting this key player in atmospheric chemical and physical processes. Recent field campaigns including the 2004 and 2006 INTEX Ozone Network Studies (IONS) http:croc.gsfc.nasa.gov/intexb/ions06.html that have included intensive ozone profile measurements from ozonesondes provide a unique data set for describing tropospheric ozone over a significant portion of the North American continent. These campaigns have focused on the spring and summer seasons when tropospheric ozone over NA is particularly influenced by long-range transport processes, significant photochemical ozone production resulting from both anthropogenic and natural (lightning) precursor emissions, and exchange with the stratosphere. This study uses ozone profiles measured over NA in the latitude band from approximately 12-60N, extending from the tropics to the high mid latitudes, to describe the seasonal behavior of tropospheric ozone over NA with an emphasis on the spring and summer. This includes the variability within seasons at a particular site as well as the contrasts between the seasons. Emphasis is placed on the variations among the sites including latitudinal and longitudinal gradients and how these differ through the seasons and with altitude in the troposphere. Regional differences are most pronounced during the summer season likely reflecting the influence of a wider variation in processes influencing the tropospheric ozone distribution including lightning NOX production in the upper

Climate Impacts on Tropospheric Ozone and Hydroxyl

NASA Technical Reports Server (NTRS)

Shindell, Drew T.; Bell, N.; Faluvegi, G.

2003-01-01

Climate change may influence tropospheric ozone and OH via several main pathways: (1) altering chemistry via temperature and humidity changes, (2) changing ozone and precursor sources via surface emissions, stratosphere-troposphere exchange, and light- ning, and (3) affecting trace gas sinks via the hydrological cycle and dry deposition. We report results from a set of coupled chemistry-climate model simulations designed to systematically study these effects. We compare the various effects with one another and with past and projected future changes in anthropogenic and natural emissions of ozone precursors. We find that white the overall impact of climate on ozone is probably small compared to emission changes, some significant seasonal and regional effects are apparent. The global effect on hydroxyl is quite large, however, similar in size to the effect of emission changes. Additionally, we show that many of the chemistry-climate links that are not yet adequately modeled are potentially important.

A Contribution Toward Understanding the Biospherical Significance of Antarctic Ozone Depletion

NASA Astrophysics Data System (ADS)

Lubin, Dan; Mitchell, B. Greg; Frederick, John E.; Alberts, Amy D.; Booth, C. R.; Lucas, Timothy; Neuschuler, David

1992-05-01

Measurements of biologically active UV radiation made by the National Science Foundation (NSF) scanning spectroradiometer (UV-monitor) at Palmer Station, Antarctica, during the Austral springs of 1988, 1989, and 1990 are presented and compared. Column ozone abundance above Palmer Station is computed from these measurements using a multiple wavelength algorithm. Two contrasting action spectra (biological weighting functions) are used to estimate the biologically relevant dose from the spectral measurements: a standard weighting function for damage to DNA, and a new action spectrum representing the potential for photosynthesis inhibition in Antarctic phytoplankton. The former weights only UV-B wavelengths (280-320 nm) and gives the most weight to wavelengths shorter than 300 nm, while the latter includes large contributions out to 355 nm. The latter is the result of recent Antarctic field work and is relevant in that phytoplankton constitute the base of the Antarctic food web. The modest ozone hole of 1988, in which the ozone abundance above Palmer Station never fell below 200 Dobson units (DU), brought about summerlike doses of DNA-effective UV radiation 2 months early, but UV doses which could inhibit photosynthesis in phytoplankton did not exceed a clear-sky "maximum normal" dose for that time of year. The severe ozone holes of 1989 and 1990, in which the ozone abundance regularly fell below 200 DU, brought about increases in UV surface irradiance weighted by either action spectrum. Ozone abundances and dose-weighted irradiances provided by the NSF UV-monitor are used to derive the radiation amplification factors (RAFs) for both DNA-effective irradiance and phytoplankton-effective irradiance. The RAF for DNA-effective irradiance is nonlinear in ozone abundance and is in excess of the popular "two for one" rule, while the RAF for phytoplankton-effective irradiance approximately follows a "one for one" rule.

Using ozone to reduce recalcitrant compounds and to enhance biodegradability of pulp and paper effluents.

PubMed

Bijan, L; Mohseni, M

2004-01-01

The effect of ozone based oxidation on removing recalcitrant organic matter (ROM) and enhancing the biodegradability of alkaline bleach plant effluent was investigated. A bubble column ozonation tower was used in the study. The experiments were carried out at different temperatures (20 degrees C and 60 degrees C) and pH (9 and 11), with a number of biological and chemical parameters being monitored including BOD5, COD, TC, pH, color, and molecular weight distribution of organics (nominal cut off of 1,000 Da). Biodegradability of the effluent was determined based on BOD5/COD of the wastewater throughout the process. For all the experiments, ozonation enhanced the biodegradability of the effluent by 30-40%, which was associated with noticeable removal of ROM including high molecular weight (HMW) and color-causing organics by about 30% and 60%, respectively. While the biodegradability of HMW fraction increased by about 50%, there was no biodegradability improvement for low molecular weight (LMW) portion, which was originally readily biodegradable (with BOD5/COD of about 0.5). Statistical analysis of variance (ANOVA) revealed neither pH nor temperature played significant role on the ozonation process at 95% confidence level.

Nonaqueous ozonation of vulcanized rubber

DOEpatents

Serkiz, Steven M.

1999-01-01

A process and resulting product is provided in which a solid particulate, such as vulcanized crumb rubber, has the surface functional groups oxidized by ozonation using a nonpolar solvent. The ozonation process renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger loading levels of the treated crumb rubber can be used in new rubber mixtures.

A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

PubMed Central

Saylor, Rachel A.; Lunte, Susan M.

2015-01-01

Microdialysis is a powerful sampling technique that enables monitoring of dynamic processes in vitro and in vivo. The combination of microdialysis with chromatographic or electrophoretic methods yields along with selective detection methods yields a “separation-based sensor” capable of monitoring multiple analytes in near real time. Analysis of microdialysis samples requires techniques that are fast (<1 min), have low volume requirements (nL–pL), and, ideally, can be employed on-line. Microchip electrophoresis fulfills these requirements and also permits the possibility of integrating sample preparation and manipulation with detection strategies directly on-chip. Microdialysis coupled to microchip electrophoresis has been employed for monitoring biological events in vivo and in vitro. This review discusses technical considerations for coupling microdialysis sampling and microchip electrophoresis, including various interface designs, and current applications in the field. PMID:25637011

Comparison of pharmaceutical abatement in various water matrices by conventional ozonation, peroxone (O3/H2O2), and an electro-peroxone process.

PubMed

Wang, Huijiao; Zhan, Juhong; Yao, Weikun; Wang, Bin; Deng, Shubo; Huang, Jun; Yu, Gang; Wang, Yujue

2018-03-01

Pharmaceutical abatement in a groundwater (GW), surface water (SW), and secondary effluent (SE) by conventional ozonation, the conventional peroxone (O 3 /H 2 O 2 ), and the electro-peroxone (E-peroxone) processes was compared in batch tests. SE had significantly more fast-reacting dissolved organic matter (DOM) moieties than GW and SW. Therefore, O 3 decomposed much faster in SE than in GW and SW. At specific ozone doses of 0.5-1.5 mg O 3 /mg dissolved organic carbon (DOC), the application of O 3 /H 2 O 2 and E-peroxone process (by adding external H 2 O 2 stocks or in-situ generating H 2 O 2 from cathodic O 2 reduction during ozonation) similarly enhanced the OH yield from O 3 decomposition by ∼5-12% and 5-7% in GW and SW, respectively, compared to conventional ozonation. In contrast, due to the slower reaction kinetics of O 3 with H 2 O 2 than O 3 with fast-reacting DOM moieties, the addition or electro-generation of H 2 O 2 hardly increased the OH yield (<4% increases) in SE. Corresponding to the changes in the OH yields, the abatement efficiencies of ozone-resistant pharmaceuticals (ibuprofen and clofibric acid) increased evidently in GW (up to ∼14-18% at a specific ozone dose of 1.5 mg O 3 /mg DOC), moderately in SW (up to 6-10% at 0.5 mg O 3 /mg DOC), and negligibly in SE during the O 3 /H 2 O 2 and E-peroxone treatment compared to conventional ozonation. These results indicate that similar to the conventional O 3 /H 2 O 2 process, the E-peroxone process can more pronouncedly enhance O 3 transformation to OH, and thus increase the abatement efficiency of ozone-resistant pharmaceuticals in water matrices exerting relatively high ozone stability (e.g., groundwater and surface water with low DOM contents). Therefore, by installing electrodes in existing ozone reactors, the E-peroxone process may provide a convenient way to enhance pharmaceutical abatement in drinking water applications, where groundwater and surface water with low DOM contents are used as

A diabatic circulation two-dimensional model with photochemistry - Simulations of ozone and long-lived tracers with surface sources

NASA Technical Reports Server (NTRS)

Stordal, F.; Isaksen, I. S. A.; Horntveth, K.

1985-01-01

Numerous studies have been concerned with the possibility of a reduction of the stratospheric ozone layer. Such a reduction could lead to an enhanced penetration of ultraviolet (UV) radiation to the ground, and, as a result, to damage in the case of several biological processes. It is pointed out that the distributions of many trace gases, such as ozone, are governed in part by transport processes. The present investigation presents a two-dimensional photochemistry-transport model using the residual circulation. The global distribution of both ozone and components with ground sources computed in this model is in good agreement with the observations even though slow diffusion is adopted. The agreement is particularly good in the Northern Hemisphere. The results provide additional support for the idea that tracer transport in the stratosphere is mainly of advective nature.

Simultaneous waste activated sludge disintegration and biological hydrogen production using an ozone/ultrasound pretreatment.

PubMed

Yang, Shan-Shan; Guo, Wan-Qian; Cao, Guang-Li; Zheng, He-Shan; Ren, Nan-Qi

2012-11-01

This paper offers an effective pretreatment method that can simultaneously achieve excess sludge reduction and bio-hydrogen production from sludge self-fermentation. Batch tests demonstrated that the combinative use of ozone/ultrasound pretreatment had an advantage over the individual ozone and ultrasound pretreatments. The optimal condition (ozone dose of 0.158 g O(3)/g DS and ultrasound energy density of 1.423 W/mL) was recommended by response surface methodology. The maximum hydrogen yield was achieved at 9.28 mL H(2)/g DS under the optimal condition. According to the kinetic analysis, the highest hydrogen production rate (1.84 mL/h) was also obtained using combined pretreatment, which well fitted the predicted equation (the squared regression statistic was 0.9969). The disintegration degrees (DD) were limited to 19.57% and 46.10% in individual ozone and ultrasound pretreatments, while it reached up to 60.88% in combined pretreatment. The combined ozone/ultrasound pretreatment provides an ideal and environmental friendly solution to the problem of sludge disposal. Copyright © 2012 Elsevier Ltd. All rights reserved.

Removal of dimethyl sulfide by the combination of non-thermal plasma and biological process.

PubMed

Wei, Z S; Li, H Q; He, J C; Ye, Q H; Huang, Q R; Luo, Y W

2013-10-01

A bench scale system integrated with a non-thermal plasma (NTP) and a biotricking filtration (BTF) unit for the treatment of gases containing dimethyl sulfide (DMS) was investigated. DMS removal efficiency in the integrated system was up to 96%. Bacterial communities in the BTF were assessed by PCR-DGGE, which play the dominant role in the biological processes of metabolism, sulfur oxidation, sulfate-reducing and carbon oxidation. The addition of ozone from NTP made microbial community in BTF more complicated and active for DMS removal. The NTP oxidize DMS to simple compounds such as methanol and carbonyl sulfide; the intermediate organic products and DMS are further oxidized to sulfate, carbon dioxide, water vapors by biological degradation. These results show that NTP-BTF is achievable and open new possibilities for applying the integrated with NTP and BTF to odour gas treatment. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

JEM spotlight: Monitoring the treatment efficiency of a full scale ozonation on a sewage treatment plant with a mode-of-action based test battery.

PubMed

Escher, Beate I; Bramaz, Nadine; Ort, Christoph

2009-10-01

Tertiary treatment of wastewater with ozone is a promising technique for removing residual micropollutants that remain after secondary biological treatment. We monitored the performance of a full-scale ozonation reactor on a sewage treatment plant in Switzerland with a screening battery of bioassays. Six toxicity endpoints were selected that covered non-specific toxicity, as well as selected receptor-mediated modes of action and reactive toxicity. Non-specific toxicity was assessed with two bioassays, the bioluminescence inhibition of the marine luminescent bacterium Vibrio Fischeri and the growth inhibition of the green algae Pseudokirchneriella subcapitata. Treatment efficiency was around 90% for the secondary treatment, but only 65% and 76% for the ozonation step in the two non-specific endpoints, respectively. This finding is consistent with this type of oxidation reaction because ozone only modifies the organic molecules but does not mineralize them fully leaving residual toxicity of the transformation products. In contrast, the specific receptor-mediated endpoints of inhibition of photosystem II in algae and estrogenicity were largely reduced by ozonation. While compounds inhibiting photosynthesis proved to be rather recalcitrant toward biological treatment with only 47% removal, an additional 86% removal by ozonation yielded an overall treatment efficiency in the entire treatment chain of 89%. The effect on estrogenicity, quantified with the yeast estrogen screen, was even more significant: A treatment efficiency of 95% in the secondary treatment, 86% during ozonation plus a small effect by biological sand filtration yielded an overall treatment efficiency of 99.5%. Insecticides that inhibit acetylcholinesterase were fairly resistant to degradation, but an overall treatment efficiency of 91% was achieved in two steps: 72% in biological treatment and 60% during ozonation. Finally, no significant genotoxicity was observed with the umuC test after ozonation

On the interannual oscillations in the northern temperate total ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krzyscin, J.W.

1994-07-01

The interannual variations in total ozone are studied using revised Dobson total ozone records (1961-1990) from 17 stations located within the latitude band 30 deg N - 60 deg N. To obtain the quasi-biennial oscillation (QBO), El Nino-Southern Oscillation (ENSO), and 11-year solar cycle manifestation in the `northern temperate` total ozone data, various multiple regression models are constructed by the least squares fitting to the observed ozone. The statistical relationships between the selected indices of the atmospheric variabilities and total ozone are described in the linear and nonlinear regression models. Nonlinear relationships to the predictor variables are found. That is,more » the total ozone variations are statistically modeled by nonlinear terms accounting for the coupling between QBO and ENSO, QBO and solar activity, and ENSO and solar activity. It is suggested that large reduction of total ozone values over the `northern temperate` region occurs in cold season when a strong ENSO warm event meets the west phase of the QBO during the period of high solar activity.« less

[Ru/AC catalyzed ozonation of recalcitrant organic compounds].

PubMed

Wang, Jian-Bing; Hou, Shao-Pei; Zhou, Yun-Rui; Zhu, Wan-Peng; He, Xu-Wen

2009-09-15

Ozonation and Ru/AC catalyzed ozonation of dimethyl phthalate (DMP), phenols and disinfection by-products precursors were studied. It shows that Ru/AC catalyst can obviously enhance the mineralization of organic compounds. In the degradation of DMP, TOC removal was 28.84% by ozonation alone while it was 66.13% by catalytic ozonation. In the oxidation of 23 kinds of phenols, TOC removals were 9.57%-56.08% by ozonation alone while they were 41.81%-82.32% by catalytic ozonation. Compared to ozonation alone, Ru/AC catalyzed ozonation was more effective for the reduction of disinfection by-products formation potentials in source water. The reduction of haloacetic acids formation potentials was more obvious than thichlomethane formation potentials. After the treatment by catalytic ozonation, the haloacetic acids formation potentials decreased from 144.02 microg/L to 58.50 microg/L, which was below the standard value of EPA. However ozonation alone could not make it reach the standard. The treatments of source water by BAC, O3 + BAC, O3/AC + BAC and Ru/AC + O3 + BAC were also studied. In the four processes, TOC removal was 3.80%, 20.14%, 27.45% and 48.30% respectively, COD removal was 4.37%, 27.22%, 39.91% and 50.00% respectively, UV254 removal was 8.16%, 62.24%, 67.03% and 84.95% respectively. Ru/AC + O3 + BAC process is more effective than the other processes for the removal of TOC, COD and UV254 and no ruthenium leaching observed in the solution. It is a promising process for the treatment of micro polluted source water.

Tropospheric jet response to Antarctic ozone depletion: An update with Chemistry-Climate Model Initiative (CCMI) models

NASA Astrophysics Data System (ADS)

Son, Seok-Woo; Han, Bo-Reum; Garfinkel, Chaim I.; Kim, Seo-Yeon; Park, Rokjin; Abraham, N. Luke; Akiyoshi, Hideharu; Archibald, Alexander T.; Butchart, N.; Chipperfield, Martyn P.; Dameris, Martin; Deushi, Makoto; Dhomse, Sandip S.; Hardiman, Steven C.; Jöckel, Patrick; Kinnison, Douglas; Michou, Martine; Morgenstern, Olaf; O’Connor, Fiona M.; Oman, Luke D.; Plummer, David A.; Pozzer, Andrea; Revell, Laura E.; Rozanov, Eugene; Stenke, Andrea; Stone, Kane; Tilmes, Simone; Yamashita, Yousuke; Zeng, Guang

2018-05-01

The Southern Hemisphere (SH) zonal-mean circulation change in response to Antarctic ozone depletion is re-visited by examining a set of the latest model simulations archived for the Chemistry-Climate Model Initiative (CCMI) project. All models reasonably well reproduce Antarctic ozone depletion in the late 20th century. The related SH-summer circulation changes, such as a poleward intensification of westerly jet and a poleward expansion of the Hadley cell, are also well captured. All experiments exhibit quantitatively the same multi-model mean trend, irrespective of whether the ocean is coupled or prescribed. Results are also quantitatively similar to those derived from the Coupled Model Intercomparison Project phase 5 (CMIP5) high-top model simulations in which the stratospheric ozone is mostly prescribed with monthly- and zonally-averaged values. These results suggest that the ozone-hole-induced SH-summer circulation changes are robust across the models irrespective of the specific chemistry-atmosphere-ocean coupling.

The Impact of Increasing Carbon Dioxide on Ozone Recovery

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Seasonal Changes in Tropospheric Ozone Concentrations over South Korea and Its Link to Ozone Precursors

NASA Astrophysics Data System (ADS)

Jung, H. C.; Moon, B. K.; Wie, J.

2017-12-01

Concentration of tropospheric ozone over South Korea has steadily been on the rise in the last decades, mainly due to rapid industrializing and urbanizing in the Eastern Asia. To identify the characteristics of tropospheric ozone in South Korea, we fitted a sine function to the surface ozone concentration data from 2005 to 2014. Based on fitted sine curves, we analyzed the shifts in the dates on which ozone concentration reached its peak in the calendar year. Ozone monitoring sites can be classified into type types: where the highest annual ozone concentration kept occurring sooner (Esites) and those that kept occurring later (Lsites). The seasonal analysis shows that the surface ozone had increased more rapidly in Esites than in Lsites in the past decade during springtime and vice-versa during summertime. We tried to find the reason for the different seasonal trends with the relationship between ozone and ozone precursors. As a result, it was found that the changes in the ground-level ozone concentration in the spring and summer times are considerably influenced by changes in nitrogen dioxide concentration, and this is closely linked to the destruction (production) process of ozone by nitrogen dioxide in spring (summer). The link between tropospheric ozone and nitrogen dioxide discussed in this study will have to be thoroughly examined through climate-chemistry modeling in the future. Acknowledgements This research was supported by the Korea Ministry of Environment (MOE) as "Climate Change Correspondence Program."

New Insights on "Next Day" Ozone Increases in the Northeastern U.S. using Continuous Vertical Profiles of Ozone

NASA Astrophysics Data System (ADS)

Sullivan, J. T.; McGee, T. J.; Rabenhorst, S. D.; Delgado, R.; Dreessen, J.; Sumnicht, G. K.; Twigg, L.

2016-12-01

A unique multi-day air quality event occurred throughout the Mid-Atlantic region from June 9-12, 2015. The June event was coupled to the advection of widespread smoke and debris from western Canada throughout the region. Observations indicated that the aged smoke impacted the Planetary Boundary Layer (PBL) and greatly enhanced ozone concentrations at the surface. Many ground sites in the region, particularly in Maryland, recorded 8-hr ozone concentrations that were in exceedance of the 75 ppb EPA National Ambient Air Quality Standard (NAAQS). After the high O3 episode occurred, a nocturnal low-level jet developed throughout the Mid-Atlantic region, which was spatially correlated with next day high O3 at several sites within the New England region. During this event, nearly continuous vertical profiles of ozone are presented at Beltsville, MD from the NASA Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL), which has been developed and validated within the Tropospheric Ozone Lidar Network (TOLNet). Lidar observations reveal a well-mixed polluted PBL, nocturnal residual layer, and subsequent mixing down of the residual layer in the morning. Additional measurements of surface ozone, aerosol lidar profiles, wind profiles, and balloon borne profiles are also presented. Model output and trajectory analyses are also presented to illustrate the complex flow regimes that occurred during the daytime and nighttime to help redistribute the polluted air mass.

Coupled Modeling of Rhizosphere and Reactive Transport Processes

NASA Astrophysics Data System (ADS)

Roque-Malo, S.; Kumar, P.

2017-12-01

The rhizosphere, as a bio-diverse plant root-soil interface, hosts many hydrologic and biochemical processes, including nutrient cycling, hydraulic redistribution, and soil carbon dynamics among others. The biogeochemical function of root networks, including the facilitation of nutrient cycling through absorption and rhizodeposition, interaction with micro-organisms and fungi, contribution to biomass, etc., plays an important role in myriad Critical Zone processes. Despite this knowledge, the role of the rhizosphere on watershed-scale ecohydrologic functions in the Critical Zone has not been fully characterized, and specifically, the extensive capabilities of reactive transport models (RTMs) have not been applied to these hydrobiogeochemical dynamics. This study uniquely links rhizospheric processes with reactive transport modeling to couple soil biogeochemistry, biological processes, hydrologic flow, hydraulic redistribution, and vegetation dynamics. Key factors in the novel modeling approach are: (i) bi-directional effects of root-soil interaction, such as simultaneous root exudation and nutrient absorption; (ii) multi-state biomass fractions in soil (i.e. living, dormant, and dead biological and root materials); (iii) expression of three-dimensional fluxes to represent both vertical and lateral interconnected flows and processes; and (iv) the potential to include the influence of non-stationary external forcing and climatic factors. We anticipate that the resulting model will demonstrate the extensive effects of plant root dynamics on ecohydrologic functions at the watershed scale and will ultimately contribute to a better characterization of efflux from both agricultural and natural systems.

Ozone Depletion at Mid-Latitudes: Coupling of Volcanic Aerosols and Temperature Variability to Anthropogenic Chlorine

NASA Technical Reports Server (NTRS)

Solomon, S.; Portmann, R. W.; Garcia, R. R.; Randel, W.; Wu, F.; Nagatani, R.; Gleason, J.; Thomason, L.; Poole, L. R.; McCormick, M. P.

1998-01-01

Satellite observations of total ozone at 40-60 deg N are presented from a variety of instruments over the time period 1979-1997. These reveal record low values in 1992-3 (after Pinatubo) followed by partial but incomplete recovery. The largest post-Pinatubo reductions and longer-term trends occur in spring, providing a critical test for chemical theories of ozone depletion. The observations are shown to be consistent with current understanding of the chemistry of ozone depletion when changes in reactive chlorine and stratospheric aerosol abundances are considered along with estimates of wave-driven fluctuations in stratospheric temperatures derived from global temperature analyses. Temperature fluctuations are shown to make significant contributions to model calculated northern mid-latitude ozone depletion due to heterogeneous chlorine activation on liquid sulfate aerosols at temperatures near 200-210 K (depending upon water vapor pressure), particularly after major volcanic eruptions. Future mid-latitude ozone recovery will hence depend not only on chlorine recovery but also on temperature trends and/or variability, volcanic activity, and any trends in stratospheric sulfate aerosol.

The total ozone and UV solar radiation over Stara Zagora, Bulgaria

NASA Astrophysics Data System (ADS)

Mendeva, B. D.; Gogosheva, Ts. N.; Petkov, B. H.; Krastev, D. G.

The results from direct ground-based solar UV irradiance measurements and the total ozone content (TOC) over Stara Zagora (42° 25'N, 25° 37'E), Bulgaria are presented. During the period 1999-2003 the TOC data show seasonal variations, typical for the middle latitudes - maximum in the spring and minimum in the autumn. The comparison between TOC ground-based data and Global Ozone Monitoring Experiment (GOME) satellite-borne ones shows a seasonal dependence of the differences between them. A strong negative relationship between the total ozone and the 305 nm wavelength irradiance was found. The dependence between the two variables is significant ( r = -0.62 ± 0.18) at 98% confidence level. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2.3%. The eye-damaging doses are more influenced by the TOC changes and in this case RAF = -2.7%. The amount of these biological doses depended on the solar altitude over the horizon. This dependence was not so strong when the total ozone content in the atmosphere was lower.

Impacts of different characterizations of large-scale background on simulated regional-scale ozone over the continental United States

NASA Astrophysics Data System (ADS)

Hogrefe, Christian; Liu, Peng; Pouliot, George; Mathur, Rohit; Roselle, Shawn; Flemming, Johannes; Lin, Meiyun; Park, Rokjin J.

2018-03-01

This study analyzes simulated regional-scale ozone burdens both near the surface and aloft, estimates process contributions to these burdens, and calculates the sensitivity of the simulated regional-scale ozone burden to several key model inputs with a particular emphasis on boundary conditions derived from hemispheric or global-scale models. The Community Multiscale Air Quality (CMAQ) model simulations supporting this analysis were performed over the continental US for the year 2010 within the context of the Air Quality Model Evaluation International Initiative (AQMEII) and Task Force on Hemispheric Transport of Air Pollution (TF-HTAP) activities. CMAQ process analysis (PA) results highlight the dominant role of horizontal and vertical advection on the ozone burden in the mid-to-upper troposphere and lower stratosphere. Vertical mixing, including mixing by convective clouds, couples fluctuations in free-tropospheric ozone to ozone in lower layers. Hypothetical bounding scenarios were performed to quantify the effects of emissions, boundary conditions, and ozone dry deposition on the simulated ozone burden. Analysis of these simulations confirms that the characterization of ozone outside the regional-scale modeling domain can have a profound impact on simulated regional-scale ozone. This was further investigated by using data from four hemispheric or global modeling systems (Chemistry - Integrated Forecasting Model (C-IFS), CMAQ extended for hemispheric applications (H-CMAQ), the Goddard Earth Observing System model coupled to chemistry (GEOS-Chem), and AM3) to derive alternate boundary conditions for the regional-scale CMAQ simulations. The regional-scale CMAQ simulations using these four different boundary conditions showed that the largest ozone abundance in the upper layers was simulated when using boundary conditions from GEOS-Chem, followed by the simulations using C-IFS, AM3, and H-CMAQ boundary conditions, consistent with the analysis of the ozone fields

Removal of micropollutants from Sakarya River water by ozone and membrane processes.

PubMed

Yaman, Fatma Büşra; Çakmakcı, Mehmet; Yüksel, Ebubekir; Özen, İsmail; Gengeç, Erhan

2017-09-01

The removal of some pollutants in the Sakarya River was investigated in this study. Sakarya River located in Turkey flows from the northeast of Afyonkarahisar City to the Black Sea. Nineteen different micropollutants including trihalomethanes (THMs), haloacetic acids (HAAs), endocrine disrupting compound (EDC) and pharmaceuticals personal care product (PPCP) groups, and water quality parameters such as dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm wavelength (UV 254 ), hardness, and conductivity values were examined. To remove the micropollutants and improve the water quality, the treatment was performed with ozone, microfiltration (MF), and ultra-filtration (UF) membranes. The highest treatment efficiency was obtained with 1 mg/L ozone dosage and UP005 UF membrane. The trihalomethan formation potential (THMFP) and haloacetic acid formation potential (HAAFP) decreased with ozone + membrane at a concentration of 79 and 75%, respectively. After the treatment with ozone + membrane, the concentration of the micropollutants in the EDC and PPCP group remained below the detection limit. It was found that by using only membrane and only ozone, the maximum DOC removal efficiency achieved was 46 and 18%, respectively; and with ozone + membrane, this efficiency increased up to 82%. The results from the High-Pressure Size Exclusion Chromatography (HPSEC) analyses pointed that the substances with high molecular weight were converted into substances with low molecular weight after the treatment. The Fourier Transform Infrared (FTIR) analysis results showed that the aromatic and aliphatic functional groups in water changed after the treatment with ozone and that the peak values decreased more after the ozone + membrane treatment.

From biological and social network metaphors to coupled bio-social wireless networks

PubMed Central

Barrett, Christopher L.; Eubank, Stephen; Anil Kumar, V.S.; Marathe, Madhav V.

2010-01-01

Biological and social analogies have been long applied to complex systems. Inspiration has been drawn from biological solutions to solve problems in engineering products and systems, ranging from Velcro to camouflage to robotics to adaptive and learning computing methods. In this paper, we present an overview of recent advances in understanding biological systems as networks and use this understanding to design and analyse wireless communication networks. We expand on two applications, namely cognitive sensing and control and wireless epidemiology. We discuss how our work in these two applications is motivated by biological metaphors. We believe that recent advances in computing and communications coupled with advances in health and social sciences raise the possibility of studying coupled bio-social communication networks. We argue that we can better utilise the advances in our understanding of one class of networks to better our understanding of the other. PMID:21643462

A Total Ozone Dependent Ozone Profile Climatology Based on Ozone-Sondes and Aura MLS Data

NASA Astrophysics Data System (ADS)

Labow, G. J.; McPeters, R. D.; Ziemke, J. R.

2014-12-01

A new total ozone-based ozone profile climatology has been created for use in satellite and/or ground based ozone retrievals. This climatology was formed by combining data from the Microwave Limb Sounder (MLS) with data from balloon sondes and binned by zone and total ozone. Because profile shape varies with total column ozone, this climatology better captures the ozone variations than the previously used seasonal climatologies, especially near the tropopause. This is significantly different than ozone climatologies used in the past as there is no time component. The MLS instrument on Aura has excellent latitude coverage and measures ozone profiles daily from the upper troposphere to the lower mesosphere at ~3.5 km resolution. Almost a million individual MLS ozone measurements are merged with data from over 55,000 ozonesondes which are then binned as a function of total ozone. The climatology consists of average ozone profiles as a function of total ozone for six 30 degree latitude bands covering altitudes from 0-75 km (in Z* pressure altitude coordinates). This new climatology better represents the profile shape as a function of total ozone than previous climatologies and shows some remarkable and somewhat unexpected correlations between total ozone and ozone in the lower altitudes, particularly in the lower and middle troposphere. These data can also be used to infer biases and errors in either the MLS retrievals or ozone sondes.

The use of artificial neural network for modeling the decolourization of acid orange 7 solution of industrial by ozonation process

NASA Astrophysics Data System (ADS)

Fatimah, S.; Wiharto, W.

2017-02-01

Acid Orange 7 (AO7) is one of the synthetic dye in the dyeing process in the textile industry. The use of this dye can produce wastewater which will be endangered if not treated well. Ozonation method is one technique to solve this problem. Ozonation is a waste processing techniques using ozone as an oxidizing agent. Variables used in this research is the ozone concentration, the initial concentration of AO7, temperature, and pH. Based on the experimental result that the optimum value decolourization percentage is 80% when the ozone concentration is 560 mg/L, the initial concentration AO7 is 14 mg/L, the temperature is 390 °C, and pH is 7,6. Decolourization efficiency of experimental results and predictions successfully modelled by the neural network architecture. The data used to construct a neural network architecture quasi newton one step secant as many as 31 data. A comparison between the predicted results of the designed ANN models and experiment was conducted. From the modeling results obtained MAPE value of 0.7763%. From the results of this artificial neural network architecture obtained the optimum value decolourization percentage in 80,64% when the concentration of ozone is 550 mg/L, the initial concentration AO7 is 11 mg/L, the temperature is 41 °C, and the pH is 7.9.

Study on an integrated process combining ozonation with ceramic ultra-filtration for decentralized supply of drinking water.

PubMed

Zhu, Jia; Fan, Xiao J; Tao, Yi; Wei, De Q; Zhang, Xi H

2014-09-19

An integrated process was specifically developed for the decentralized supply of drinking water from micro-polluted surface water in the rural areas of China. The treatment process combined ozonation with ceramic ultra-filtration (UF), coagulation for pre-treatment and granular activated carbon filtration. A flat-sheet ceramic membrane was used with a cut-off of 60 nm and the measurement of 254 mm (length) × 240 mm (width) × 6 mm (thickness). Ozonation and ceramic UF was set up whthin one reactor. The experimental results showed that the removal efficiencies of the dissolved organic carbon (DOC) and the formation potential of trihalomethanes (THMs), haloacetic acids (HAAs) and ammonia were 80%, 76%, 70% and 90%, respectively; that the turbidity of the product water was below 0.2 NTU and the particle count number (particles larger than 2 μm) was less than 50 counts per mL. The result also showed that all the pathogenic microorganisms were retained by the ceramic and that UF. Ozonation played a critical role in the control of membrane fouling and the removal of contaminants. Exactly, the membrane fouling can be controlled in situ with 3 mg L(-1) ozone at the permeate flux of 80 L m(-2) h(-1), yet the required dosage of ozone was dependent on the quality of the raw water. Therefore, this study is able to provide a highly compacted system for decentralized supply of high-quality drinking water in terms of both chemical and microbiological safety for the rural areas in China.

A finite element simulation of biological conversion processes in landfills.

PubMed

Robeck, M; Ricken, T; Widmann, R

2011-04-01

Landfills are the most common way of waste disposal worldwide. Biological processes convert the organic material into an environmentally harmful landfill gas, which has an impact on the greenhouse effect. After the depositing of waste has been stopped, current conversion processes continue and emissions last for several decades and even up to 100years and longer. A good prediction of these processes is of high importance for landfill operators as well as for authorities, but suitable models for a realistic description of landfill processes are rather poor. In order to take the strong coupled conversion processes into account, a constitutive three-dimensional model based on the multiphase Theory of Porous Media (TPM) has been developed at the University of Duisburg-Essen. The theoretical formulations are implemented in the finite element code FEAP. With the presented calculation concept we are able to simulate the coupled processes that occur in an actual landfill. The model's theoretical background and the results of the simulations as well as the meantime successfully performed simulation of a real landfill body will be shown in the following. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ozonation of Canadian Athabasca asphaltene

NASA Astrophysics Data System (ADS)

Cha, Zhixiong

. Two new solvent systems, a self-sustaining ozonation system and a cyclohexane/acetone/water or a cyclohexane/acetone/methanol system, were studied to overcome the drawback of using halogenated solvents. The self-sustaining ozonation process employed the final ozonation products as the reaction solvent. Compared to the self-sustaining ozonation, the cyclohexane solvent system showed higher ozone efficiency; however, it required dynamic adjustment of the solvent system during ozonation. An extensively ozonated asphaltene's weight would be doubled. Distillation of the products separated about 45% volatile products having biodiesel-style chemical structures. Compared to distillation, more than 90% of the ozonation products were extractable by acetone. The remaining acetone-insoluble part was further classified by dichloromethane and other solvents of different polarities. The separated ozonation products were good fuel additives or materials for other products.

Modular and efficient ozone systems based on massively parallel chemical processing in microchannel plasma arrays: performance and commercialization

NASA Astrophysics Data System (ADS)

Kim, M.-H.; Cho, J. H.; Park, S.-J.; Eden, J. G.

2017-08-01

Plasmachemical systems based on the production of a specific molecule (O3) in literally thousands of microchannel plasmas simultaneously have been demonstrated, developed and engineered over the past seven years, and commercialized. At the heart of this new plasma technology is the plasma chip, a flat aluminum strip fabricated by photolithographic and wet chemical processes and comprising 24-48 channels, micromachined into nanoporous aluminum oxide, with embedded electrodes. By integrating 4-6 chips into a module, the mass output of an ozone microplasma system is scaled linearly with the number of modules operating in parallel. A 115 g/hr (2.7 kg/day) ozone system, for example, is realized by the combined output of 18 modules comprising 72 chips and 1,800 microchannels. The implications of this plasma processing architecture for scaling ozone production capability, and reducing capital and service costs when introducing redundancy into the system, are profound. In contrast to conventional ozone generator technology, microplasma systems operate reliably (albeit with reduced output) in ambient air and humidity levels up to 90%, a characteristic attributable to the water adsorption/desorption properties and electrical breakdown strength of nanoporous alumina. Extensive testing has documented chip and system lifetimes (MTBF) beyond 5,000 hours, and efficiencies >130 g/kWh when oxygen is the feedstock gas. Furthermore, the weight and volume of microplasma systems are a factor of 3-10 lower than those for conventional ozone systems of comparable output. Massively-parallel plasmachemical processing offers functionality, performance, and commercial value beyond that afforded by conventional technology, and is currently in operation in more than 30 countries worldwide.

Interhemispheric Differences in Dentifrication and Related Processes Affecting Polar Ozone

NASA Technical Reports Server (NTRS)

Santee, M. L.; Read, W. G.; Waters, J. W.; Froidevaux, L.; Manney, G. L.; Flower, D. A.; Jarnot, R. F.; Harwood, R. S.; Peckham, G. E.

1994-01-01

The severe depletion of stratospheric ozone over Antarctica in late winter and early spring is caused by enhanced CLO abundances arising from heterogeneous reactions on polar stratospheric clouds (PSCs). CLO abundances comparable to those over Antarctica have also been observed throughout the Arctic Vortex, but the accompanying loss of Arctic ozone has been much less severe.

High School and College Student Perceptions of the Ozone Depletion Problem.

ERIC Educational Resources Information Center

Groves, Fred; Pugh, Ava

This paper examines the knowledge of high school biology students (n=107), undergraduate elementary education majors (n=42), and graduate students in an advanced elementary science methods course (n=22) about ozone depletion. The questionnaire used contained 30 items pertaining to ozone depletion which were divided into three subscales: (1)…

Application of ozone in the treatment of periodontal disease

PubMed Central

Srikanth, Adusumilli; Sathish, Manthena; Sri Harsha, Anumolu Venkatanaga

2013-01-01

Gingivitis and periodontitis are most common inflammatory diseases of supporting tissues of teeth. Role of microbial etiology and host response in progression of gingival and periodontal diseases has been well established. Because of the beneficial biological effects of ozone, due to its antimicrobial and immunostimulating effect, it is well indicated in the treatment of gingival and periodontal diseases. The objective of this article is to provide a general review about clinical applications of ozone in treatment of periodontal diseases and to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. PMID:23946585

On the Size of the Antarctic Ozone Hole

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph

2002-01-01

The Antarctic ozone hole is a region of extremely large ozone depletion that is roughly centered over the South Pole. Since 1979, the area coverage of the ozone hole has grown from near zero size to over 24 Million sq km. In the 8-year period from 1981 to 1989, the area expanded by 18 Million sq km. During the last 5 years, the hole has been observed to exceed 25 Million sq km over brief periods. In the spring of 2002, the size of the ozone hole barely reached 20 Million sq km for only a couple of days. We will review these size observations, the size trends, and the interannual variability of the size. The area is derived from the area enclosed by the 220 DU total ozone contour. We will discuss the rationale for the choice of 220 DU: 1) it is located near the steep gradient between southern mid-latitudes and the polar region, and 2) 220 DU is a value that is lower than the pre-1979 ozone observations over Antarctica during the spring period. The phenomenal growth of the ozone hole was directly caused by the increases of chlorine and bromine compounds in the stratosphere. In this talk, we will show the relationship of the ozone hole's size to the interannual variability of Antarctic spring temperatures. In addition, we will show the relationship of these same temperatures to planetary-scale wave forcings.

Effect of Pulse Width on Oxygen-fed Ozonizer

NASA Astrophysics Data System (ADS)

Okada, Sho; Wang, Douyan; Namihira, Takao; Katsuki, Sunao; Akiyama, Hidenori

Though general ozonizers based on silent discharge (barrier discharge) have been used to supply ozone at many industrial situations, there is still some problem, such as improvements of ozone yield. In this work, ozone was generated by pulsed discharge in order to improve the characteristics of ozone generation. It is known that a pulse width gives strong effect to the improvement of energy efficiency in exhaust gas processing. In this paper, the effect of pulse duration on ozone generation by pulsed discharge in oxygen would be reported.

Seasonal Characteristics of Widespread Ozone Pollution in China and India: Current Model Capabilities and Source Attributions

NASA Astrophysics Data System (ADS)

Gao, M.; Song, S.; Beig, G.; Zhang, H.; Hu, J.; Ying, Q.; McElroy, M. B.

2017-12-01

Fast urbanization and industrialization in China and India have led to severe ozone pollution, threatening public health in these densely populated countries. We show the spatial and seasonal characteristics of ozone concentrations using nation-wide observations for these two countries in 2013. We used the Weather Research and Forecasting model coupled to chemistry (WRF-Chem) to conduct one-year simulations and to evaluate how current models capture the important photochemical processes using the exhaustive available datasets in China and India, including surface measurements, ozonesonde data and satellite retrievals. We also employed the factor separation approach to distinguish the contributions of different sectors to ozone during different seasons. The back trajectory model FLEXPART was applied to investigate the role of transport in highly polluted regions (e.g., North China Plain, Yangtze River delta, and Pearl River Delta) during different seasons. Preliminary results indicate that the WRF-Chem model provides a satisfactory representation of the temporal and spatial variations of ozone for both China and India. The factor separation approach offers valuable insights into relevant sources of ozone for both countries providing valuable guidance for policy options designed to mitigate the related problem.

TOLNet - A Tropospheric Ozone Lidar Profiling Network for Satellite Continuity and Process Studies

NASA Technical Reports Server (NTRS)

Newchurch, Michael J.; Kuang, Shi; Wang, Lihua; LeBlanc, Thierry; Alvarez II, Raul J.; Langford, Andrew O.; Senff, Christoph J.; Brown, Steve; Johnson, Bryan; Burris, John F.;

Ozone depletion following future volcanic eruptions

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Effects of ozonated sewage effluent on reproduction and behavioral endpoints in zebrafish (Danio rerio).

PubMed

Pohl, Johannes; Björlenius, Berndt; Brodin, Tomas; Carlsson, Gunnar; Fick, Jerker; Larsson, D G Joakim; Norrgren, Leif; Örn, Stefan

2018-04-25

Pharmaceutical residues and other micro-contaminants may enter aquatic environments through effluent from sewage treatment plants (STPs) and could cause adverse effects in wild fish. One strategy to alleviate this situation is to improve wastewater treatment by ozonation. To test the effectiveness of full-scale wastewater effluent ozonation at a Swedish municipal STP, the added removal efficiency was measured for 105 pharmaceuticals. In addition, gene expression, reproductive and behavioral endpoints were analyzed in zebrafish (Danio rerio) exposed on-site over 21 days to ozonated or non-ozonated effluents as well as to tap water. Ozone treatment (7 g O 3 /m 3 ) removed pharmaceuticals by an average efficiency of 77% in addition to the conventional treatment, leaving 11 screened pharmaceuticals above detection limits. Differences in biological responses of the exposure treatments were recorded in gene expression, reproduction and behavior. Hepatic vitellogenin gene expression was higher in male zebrafish exposed to the ozonated effluent compared to the non-ozonated effluent and tap water treatments. The reproductive success was higher in fish exposed to ozonated effluent compared to non-ozonated effluent and to tap water. The behavioral measurements showed that fish exposed to the ozonated STP effluent were less active in swimming the first minute after placed in a novel vessel. Ozonation is a capable method for removing pharmaceuticals in effluents. However, its implementation should be thoroughly evaluated for any potential biological impact. Future research is needed for uncovering the factors which produced the in vivo responses in fish. Copyright © 2018 Elsevier B.V. All rights reserved.

Simulation of tropospheric ozone with MOZART-2: An evaluation study over East Asia

NASA Astrophysics Data System (ADS)

Liu, Qianxia; Zhang, Meigen; Wang, Bin

2005-07-01

Climate changes induced by human activities have attracted a great amount of attention. With this, a coupling system of an atmospheric chemistry model and a climate model is greatly needed in China for better understanding the interaction between atmospheric chemical components and the climate. As the first step to realize this coupling goal, the three-dimensional global atmospheric chemistry transport model MOZART-2 (the global Model of Ozone and Related Chemical Tracers, version 2) coupled with CAM2 (the Community Atmosphere Model, version 2) is set up and the model results are compared against observations obtained in East Asia in order to evaluate the model performance. Comparison of simulated ozone mixing ratios with ground level observations at Minamitorishima and Ryori and with ozonesonde data at Naha and Tateno in Japan shows that the observed ozone concentrations can be reproduced reasonably well at Minamitorishima but they tend to be slightly overestimated in winter and autumn while underestimated a little in summer at Ryori. The model also captures the general features of surface CO seasonal variations quite well, while it underestimates CO levels at both Minamitorishima and Ryori. The underestimation is primarily associated with the emission inventory adopted in this study. Compared with the ozonesonde data, the simulated vertical gradient and magnitude of ozone can be reasonably well simulated with a little overestimation in winter, especially in the upper troposphere. The model also generally captures the seasonal, latitudinal and altitudinal variations in ozone concentration. Analysis indicates that the underestimation of tropopause height in February contributes to the overestimation of winter ozone in the upper and middle troposphere at Tateno.

Impact of diatomite on the slightly polluted algae-containing raw water treatment process using ozone oxidation coupled with polyaluminum chloride coagulation.

PubMed

Hu, Wenchao; Wu, Chunde; Jia, Aiyin; Zhang, Zhilin; Chen, Fang

2014-01-01

The impact of adding diatomite on the treatment performance of slightly polluted algae-containing raw water using ozone pre-oxidation and polyaluminum chloride (PAC) coagulation was investigated. Results demonstrated that the addition of diatomite is advantageous due to reduction of the PAC dose (58.33%) and improvement of the removal efficiency of algae, turbidity, and dissolved organic matter (DOM) in raw water. When the ozone concentration was 1.0 mg L⁻¹ and the PAC dosage was 2.5 mg L⁻¹, the removal rates of algae, turbidity, UV254, and TOC were improved by 6.39%, 7.06%, 6.76%, and 4.03%, respectively, with the addition of 0.4 g L⁻¹ diatomite. It has been found that the DOM presented in the Pearl River raw water mainly consisted of small molecules (<1 kDa) and large ones (> 50 kDa). After adding diatomite (0.4 g L⁻¹), the additional removal of 5.77% TOC and 14.82% UV254 for small molecules (<1 kDa) of DOM, and 8.62% TOC and 7.33% UV254 for large ones (>50 kDa) could be achieved, respectively, at an ozone concentration of 1.0 mg L⁻¹ and a PAC dose of 2.5 mg L⁻¹. The growth of anabaena flos-aquae (A.F.) was observed by an atomic force microscope (AFM) before and after adding diatomite. AFM images demonstrate that diatomite may have a certain adsorption on A.F.

The impact of climate change on ozone-related mortality in Sydney.

PubMed

Physick, William; Cope, Martin; Lee, Sunhee

2014-01-13

Coupled global, regional and chemical transport models are now being used with relative-risk functions to determine the impact of climate change on human health. Studies have been carried out for global and regional scales, and in our paper we examine the impact of climate change on ozone-related mortality at the local scale across an urban metropolis (Sydney, Australia). Using three coupled models, with a grid spacing of 3 km for the chemical transport model (CTM), and a mortality relative risk function of 1.0006 per 1 ppb increase in daily maximum 1-hour ozone concentration, we evaluated the change in ozone concentrations and mortality between decades 1996-2005 and 2051-2060. The global model was run with the A2 emissions scenario. As there is currently uncertainty regarding a threshold concentration below which ozone does not impact on mortality, we calculated mortality estimates for the three daily maximum 1-hr ozone concentration thresholds of 0, 25 and 40 ppb. The mortality increase for 2051-2060 ranges from 2.3% for a 0 ppb threshold to 27.3% for a 40 ppb threshold, although the numerical increases differ little. Our modeling approach is able to identify the variation in ozone-related mortality changes at a suburban scale, estimating that climate change could lead to an additional 55 to 65 deaths across Sydney in the decade 2051-2060. Interestingly, the largest increases do not correspond spatially to the largest ozone increases or the densest population centres. The distribution pattern of changes does not seem to vary with threshold value, while the magnitude only varies slightly.

The Impact of Climate Change on Ozone-Related Mortality in Sydney

PubMed Central

Physick, William; Cope, Martin; Lee, Sunhee

2014-01-01

Coupled global, regional and chemical transport models are now being used with relative-risk functions to determine the impact of climate change on human health. Studies have been carried out for global and regional scales, and in our paper we examine the impact of climate change on ozone-related mortality at the local scale across an urban metropolis (Sydney, Australia). Using three coupled models, with a grid spacing of 3 km for the chemical transport model (CTM), and a mortality relative risk function of 1.0006 per 1 ppb increase in daily maximum 1-hour ozone concentration, we evaluated the change in ozone concentrations and mortality between decades 1996–2005 and 2051–2060. The global model was run with the A2 emissions scenario. As there is currently uncertainty regarding a threshold concentration below which ozone does not impact on mortality, we calculated mortality estimates for the three daily maximum 1-hr ozone concentration thresholds of 0, 25 and 40 ppb. The mortality increase for 2051–2060 ranges from 2.3% for a 0 ppb threshold to 27.3% for a 40 ppb threshold, although the numerical increases differ little. Our modeling approach is able to identify the variation in ozone-related mortality changes at a suburban scale, estimating that climate change could lead to an additional 55 to 65 deaths across Sydney in the decade 2051–2060. Interestingly, the largest increases do not correspond spatially to the largest ozone increases or the densest population centres. The distribution pattern of changes does not seem to vary with threshold value, while the magnitude only varies slightly. PMID:24419047

The Effects of Acid Passivation, Tricresyl Phosphate Pre-Soak, and UV/Ozone Treatment on the Tribology of Perfluoropolyether-Lubricated 440C Stainless Steel Couples

NASA Technical Reports Server (NTRS)

Shogrin, Bradley A.; Jones, William R., Jr.; Herrera-Fierro, Pilar

1997-01-01

The boundary-lubrication performance of perfluoropolyether (PFPE) thin films in the presence of passivated 440 C stainless steel is presented. The study utilized a standard ball-on-disc tribometer. Stainless steel surfaces were passivated with one of four techniques: 1) submersion in a chromic acid bath for 30 minutes at 46 C, 2) submersion in a chromic acid bath for 60 minutes at 56 C, 3) submersion in a tricresyl phosphate (TCP) bath for 2 days at 107 C, or 4) UV/Ozone treated for 15 minutes. After passivation, each disc had a 400 A film of PFPE (hexafluoropropene oxide) applied to it reproducibly (+/- 20%) and uniformly (+/- 15%) using a film deposition device. The lifetimes of these films were quantified by measuring the number of sliding wear cycles required to induce an increase in the friction coefficient from an initial value characteristic of the lubricated wear couple to a final, or failure value, characteristic of an unlubricated, unpassivated wear couple. The lubricated lifetime of the 440 C couple was not altered as a result of the various passivation techniques. The resulting surface chemistry of each passivation technique was examined using X-ray Photoelectron Spectroscopy (XPS). It was found that chromic acid passivation altered the Cr to Fe ratio of the surface. TCP passivation resulted in a FePO4 layer on the surface, while UV/Ozone passivation only removed the carbonaceous contamination layer. None of the passivation techniques were found to dramatically increase the oxide film thickness.

Species-specific effects of elevated ozone on wetland plants and decomposition processes.

PubMed

Williamson, Jennifer; Mills, Gina; Freeman, Chris

2010-05-01

Seven species from two contrasting wetlands, an upland bog and a lowland rich fen in North Wales, UK, were exposed to elevated ozone (150 ppb for 5 days and 20 ppb for 2 days per week) or low ozone (20 ppb) for four weeks in solardomes. The rich fen species were: Molinia caerulea, Juncus subnodulosus, Potentilla erecta and Hydrocotyle vulgaris and the bog species were: Carex echinata, Potentilla erecta and Festuca rubra. Senescence significantly increased under elevated ozone in all seven species but only Molinia caerulea showed a reduction in biomass under elevated ozone. Decomposition rates of plants exposed to elevated ozone, as measured by carbon dioxide efflux from dried plant material inoculated with peat slurry, increased for Potentilla erecta with higher hydrolytic enzyme activities. In contrast, a decrease in enzyme activities and a non-significant decrease in carbon dioxide efflux occurred in the grasses, sedge and rush species. Copyright 2010 Elsevier Ltd. All rights reserved.

Natural zeolite reactivity towards ozone: the role of compensating cations.

PubMed

Valdés, Héctor; Alejandro, Serguei; Zaror, Claudio A

2012-08-15

Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L(-1)). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH(3)-TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal. Copyright © 2012 Elsevier B.V. All rights reserved.

Wintertime ozone fluxes and profiles above a subalpine spruce-fir forest

Treesearch

Karl Zeller

2000-01-01

High rural concentrations of ozone (O3) are thought to be stratospheric in origin, advected from upwind urban sources, or photochemically generated locally by natural trace gas emissions. Ozone is known to be transported vertically downward from the above-canopy atmospheric surface layer and destroyed within stomata or on other biological and mineral surfaces. However...

Standardizing Interfaces for External Access to Data and Processing for the NASA Ozone Product Evaluation and Test Element (PEATE)

NASA Technical Reports Server (NTRS)

Tilmes, Curt A.; Fleig, Albert J.

2008-01-01

NASA's traditional science data processing systems have focused on specific missions, and providing data access, processing and services to the funded science teams of those specific missions. Recently NASA has been modifying this stance, changing the focus from Missions to Measurements. Where a specific Mission has a discrete beginning and end, the Measurement considers long term data continuity across multiple missions. Total Column Ozone, a critical measurement of atmospheric composition, has been monitored for'decades on a series of Total Ozone Mapping Spectrometer (TOMS) instruments. Some important European missions also monitor ozone, including the Global Ozone Monitoring Experiment (GOME) and SCIAMACHY. With the U.S.IEuropean cooperative launch of the Dutch Ozone Monitoring Instrument (OMI) on NASA Aura satellite, and the GOME-2 instrumental on MetOp, the ozone monitoring record has been further extended. In conjunction with the U.S. Department of Defense (DoD) and the National Oceanic and Atmospheric Administration (NOAA), NASA is now preparing to evaluate data and algorithms for the next generation Ozone Mapping and Profiler Suite (OMPS) which will launch on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) in 2010. NASA is constructing the Science Data Segment (SDS) which is comprised of several elements to evaluate the various NPP data products and algorithms. The NPP SDS Ozone Product Evaluation and Test Element (PEATE) will build on the heritage of the TOMS and OM1 mission based processing systems. The overall measurement based system that will encompass these efforts is the Atmospheric Composition Processing System (ACPS). We have extended the system to include access to publically available data sets from other instruments where feasible, including non-NASA missions as appropriate. The heritage system was largely monolithic providing a very controlled processing flow from data.ingest of

Scientific assessment of stratospheric ozone: 1989, volume 1

NASA Technical Reports Server (NTRS)

1990-01-01

A scientific review is presented of the current understanding of stratospheric ozone. There have been highly significant advances in the understanding of the impact of human activities on the Earth's protective ozone layer. There are four major findings that each heighten the concern that chlorine and bromine containing chemicals can lead to a significant depletion of stratospheric ozone: (1) Antarctic ozone hole (the weight of evidence indicates that chlorinated and brominated chemicals are responsible for the ozone hole; (2) Perturbed arctic chemistry (the same potentially ozone destroying processes were identified in the Arctic stratosphere); (3) Long term ozone decreases; and (4) Model limitations (gaps in theoretical models used for assessment studies).

Application of quantitative structure activity relationship (QSAR) models to predict ozone toxicity in the lung.

PubMed

Kafoury, Ramzi M; Huang, Ming-Ju

2005-08-01

The sequence of events leading to ozone-induced airway inflammation is not well known. To elucidate the molecular and cellular events underlying ozone toxicity in the lung, we hypothesized that lipid ozonation products (LOPs) generated by the reaction of ozone with unsaturated fatty acids in the epithelial lining fluid and cell membranes play a key role in mediating ozone-induced airway inflammation. To test our hypothesis, we ozonized 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and generated LOPs. Confluent human bronchial epithelial cells were exposed to the derivatives of ozonized POPC-9-oxononanoyl, 9-hydroxy-9-hydroperoxynonanoyl, and 8-(5-octyl-1,2,4-trioxolan-3-yl-)octanoyl-at a concentration of 10 muM, and the activity of phospholipases A2 (PLA2), C (PLC), and D (PLD) was measured (1, 0.5, and 1 h, respectively). Quantitative structure-activity relationship (QSAR) models were utilized to predict the biological activity of LOPs in airway epithelial cells. The QSAR results showed a strong correlation between experimental and computed activity (r = 0.97, 0.98, 0.99, for PLA2, PLC, and PLD, respectively). The results indicate that QSAR models can be utilized to predict the biological activity of the various ozone-derived LOP species in the lung. Copyright 2005 Wiley Periodicals, Inc.

Biological treatment of fracturing waste liquid in a membrane-coupled internal circulation aerobic biological fluidized bed with the assistance of coagulation.

PubMed

Tu, Yizhou; Liu, Xing-Peng; Li, Hui-Qiang; Yang, Ping

2017-12-01

Fracturing waste liquid (FWL) is generated during shale gas extraction and contains high concentrations of suspended solid, salinity and organic compounds, which needs proper management to prevent excessive environmental disruption. Biological treatment of the FWL was attempted in this study using a membrane-coupled internal circulation aerobic biological fluidized bed (MC-ICABFB) after being treated by coagulation. The results showed that poly aluminum chloride (PAC) of 30 g/L, polyacrylamide (PAM) of 20 mg/L and pH of 7.0 were suitable choices for coagulation. The pretreated FWL mixed with synthetic wastewater at different ratios were used as the influent wastewater for the reactor. The MC-ICABFB had relatively good performance on COD and NH 4 + -N removal and the main residual organic compound in the effluent was phthalates according to the analysis of GC-MC profiles. In addition, a suitable pretreatment process for the FWL to facilitate biological treatment of the wastewater needs further research.

Kinetics and efficiency of ozone for treatment of landfill leachate including the effect of previous microbiological treatment.

PubMed

Lovato, María; Buffelli, José Real; Abrile, Mariana; Martín, Carlos

2018-03-19

The application of conventional physicochemical and microbiological techniques for the removal of organic pollutants has limitations for its utilization on wastewaters as landfill leachates because of their high concentration of not easily biodegradable organic compounds. The use of ozone-based technologies is an alternative and complementary treatment for this type of wastewaters. This paper reports the study of the degradation of landfill leachates from different stages of a treatment plant using ozone and ozone + UV. The experimental work included the determination of the temporal evolution of COD, TOC, UV254, and color. Along the experimental runs, the instantaneous off-gas ozone concentration was measured. The reaction kinetics follows a global second order expression with respect to COD and ozone concentrations. A kinetic model which takes into account the gas liquid mass transfer coupled with the chemical reaction was developed, and the corresponding parameters of the reacting system were determined. The mathematical model is able to appropriately simulate COD and ozone concentrations but exhibiting limitations when varying the leachate type. The potential application of ozone was verified, although the estimated efficiencies for COD removal and ozone consumption as well as the effect of UV radiation show variations on their trends. In this sense, it is interesting to note that the relative ozone yield has significant oscillations as the reaction proceeds. Finally, the set of experimental results demonstrates the crucial importance of the selection of process conditions to improve ozone efficiencies. This approach should consider variations in the ozone supply in order to minimize losses as well as the design of exhaustion methods as multiple stage reactors using chemical engineering design tools.

Liquid-phase study of ozone inactivation of Venezuelan equine encephalomyelitis virus.

PubMed

Akey, D H; Walton, T E

1985-10-01

Ozone, in a liquid-phase application, was evaluated as a residue-free viral inactivant that may be suitable for use in an arboviral research laboratory. Commonly used sterilizing agents may leave trace residues, be flammable or explosive, and require lengthy periods for gases or residues to dissipate after decontamination of equipment such as biological safety cabinets. Complete liquid-phase inactivation of Venezuelan equine encephalomyelitis virus was attained at 0.025 mg of ozone per liter within 45 min of exposure. The inactivation of 10(6.5) median cell culture infective doses (CCID50 of Venezuelan equine encephalomyelitis virus per milliliter represented a reduction of 99.99997% of the viral particles from the control levels of 10(7.25-7.5) CCID50/ml. A dose-response relationship was demonstrated. Analysis by polynomial regression of the logarithmic values for both ozone concentrations and percent reduction of viral titers had a highly significant r2 of 0.8 (F = 63.6; df = 1, 16). These results, together with those of Akey (J. Econ. Entomol. 75:387-392, 1982) on the use of ozone to kill a winged arboviral vector, indicate that ozone is a promising candidate as a sterilizing agent in some applications for biological safety cabinets and other equipment used in vector studies with arboviruses.

A numerical study of tropospheric ozone in the springtime in East Asia

NASA Astrophysics Data System (ADS)

Zhang, Meigen; Xu, Yongfu; Itsushi, Uno; Hajime, Akimoto

2004-04-01

The Models-3 Community Multi-scale Air Quality modeling system (CMAQ) coupled with the Regional Atmospheric Modeling System (RAMS) is applied to East Asia to study the transport and photochemical transformation of tropospheric ozone in March 1998. The calculated mixing ratios of ozone and carbon monoxide are compared with ground level observations at three remote sites in Japan and it is found that the model reproduces the observed features very well. Examination of several high episodes of ozone and carbon monoxide indicates that these elevated levels are found in association with continental outflow, demonstrating the critical role of the rapid transport of carbon monoxide and other ozone precursors from the continental boundary layer. In comparison with available ozonesonde data, it is found that the model-calculated ozone concentrations are generally in good agreement with the measurements, and the stratospheric contribution to surface ozone mixing ratios is quite limited.

Total Ozone from the Ozone Monitoring System (OMI) using TOMS and DOAS Methods

NASA Technical Reports Server (NTRS)

Veefkind, J. P.; Bhartia, P. K.; Gleason, J.; deHaan, J. F.; Wellemeyer, C.; Levelt, P. F.

2003-01-01

The Ozone Monitoring Instrument (OMI) is the Dutch-Finnish contribution to NASA's EOS-Aura satellite scheduled for launch in January 2004. OMI is an imaging spectrometer that will measure the back-scattered Solar radiance in the wavelength range of 270 to 500 nm. The instrument provides near global coverage in one day with a spatial resolution of 13x24 square kilometers. OMI is a new instrument, with a heritage from TOMS, SBW, GOME, GOMOS and SCIAMACHY. OMI'S unique capabilities for measuring important trace gases and aerosols with a small footprint and daily global coverage, in conjunction with the other Aura instruments, will make a major contribution to our understanding of stratospheric and tropospheric chemistry and climate change. OMI will provide data continuity with the 23-year ozone record of TOMS. There are three ozone products planned for OMI: total column ozone, ozone profile and tropospheric column ozone. We are developing two different algorithms for total column ozone: one similar to the algorithm currently being used to process the TOMS data, and the other an improved version of the differential optical absorption spectroscopy (DOAS) method, which has been applied to GOME and SCIAMACHY data. The main reasons for starting with two algorithms for total ozone have to do with heritage and past experience; our long-term goal is to combine the two to develop a more accurate and reliable total ozone product for OMI. We will compare the performance of these two algorithms by applying both of them to the GOME data. We will examine where and how the results differ, and use the extensive TOMS-Dobson comparison studies to assess the performance of the DOAS algorithm.

Effects of black carbon and boundary layer interaction on surface ozone in Nanjing, China

NASA Astrophysics Data System (ADS)

Gao, Jinhui; Zhu, Bin; Xiao, Hui; Kang, Hanqing; Pan, Chen; Wang, Dongdong; Wang, Honglei

2018-05-01

As an important solar radiation absorbing aerosol, the effect of black carbon (BC) on surface ozone, via reducing photolysis rate, has been widely discussed by offline model studies. However, BC-boundary layer (BL) interactions also influence surface ozone. Using the online model simulations and process analysis, we demonstrate the significant impact of BC-BL interaction on surface ozone in Nanjing. The absorbing effect of BC heats the air above the BL and suppresses and delays the development of the BL, which eventually leads to a change in surface ozone via a change in the contributions from chemical and physical processes (photochemistry, vertical mixing and advection). For chemical processes, the suppression of the BL leads to large amounts of ozone precursors being confined below the BL which has an increased effect on ozone chemical production and offsets the decrease caused by the reduction of the photolysis rate, thus enhancing ozone chemical formation from 10:00 to 12:00 LT. Furthermore, changes in physical processes, especially the vertical mixing process, show a more significant influence on surface ozone. The weakened turbulence, caused by the suppressed BL, entrains much less ozone aloft down to the surface. Finally, summing-up the changes in the processes, surface ozone reduces before noon and the maximum reduction reaches 16.4 ppb at 12:00 LT. In the afternoon, the changes in chemical process are small which inconspicuously influence surface ozone. However, change in the vertical mixing process still influences surface ozone significantly. Due to the delayed development of the BL, there are obvious ozone gradients around the top of BL. Therefore, high concentrations of ozone aloft can still be entrained down to the surface which offsets the reduction of surface ozone. Comparing the changes in the processes, the change in vertical mixing plays the most important role in impacting surface ozone. Our results highlight the great impacts BC

Leaf-level to Canopy Exchange of NOx and Ozone in a Forest at the University of Michigan Biological Station

NASA Astrophysics Data System (ADS)

Wang, W.; Ganzeveld, L.; Helmig, D.; Hueber, J.; Rossabi, S.; Vogel, C. S.

2017-12-01

During the month-long PROPHET-AMOS campaign in July, 2016 we investigated NOx and ozone dynamics at the University of Michigan AmeriFlux Tower (US-UMB tower) and the PROPHET Tower research sites at the University of Michigan Biological Station (UMBS), using a multi-pronged experimental approach. The two sites are within 100 m of each other, located in a mixed forest on the northern lower peninsula of Michigan, USA. In a previous study, it was found that invoking a leaf-level compensation point for NOx uptake and emission provided better agreement between observed and model-simulated in- and above-canopy NOx concentrations in this forest. To further examine the role of foliar exchange relative to other in-canopy sources and sinks of NOx, we conducted detailed vertical gradient measurements of NOx and ozone at ten heights from the forest floor to above the canopy, along with micrometeorological conditions at the AmeriFlux Tower. In parallel, to investigate the leaf-level exchanges of NOx and ozone, we carried out branch enclosure experiments near the PROPHET tower on the dominant tree species of this forest. We combine these observations with micrometeorological data from the AmeriFlux Tower to constrain simulations with the Multi-Layer Canopy Chemical Exchange Model (MLC-CHEM) for investigation of sources, sinks, and dynamics that determine NOx concentrations, vertical gradients, and fluxes in this forest. We will compare our results with previous studies and other observations during the PHOPHET-AMOS campaign.

[Phospholipids under combined ozone-oxygen administration].

PubMed

Müller-Tyl, E; Hernuss, P; Salzer, H; Reisinger, L; Washüttl, J; Wurst, F

1975-01-01

The parenterally application of oxygen-ozone gas mixture gives good resultats in the treatment of various deseases. Ozone seems to influence the metabolic process of fat, so it was of interest to analyse this influence especially to phospholipids. 40 women with gynaecological cancer got 10 ml oxygen-ozone gas mixture with a content of 450 gamma ozone into the cubital vene. Venous blood was removed before and 10 minutes after application and the level of lecithin, lysolecithin, cephalin and spingomyelin was determined by the method of Randerath. A decrease of all four substances was obvious, although all values remained in normal range.

[Effect of ozone on membrane fouling in water and wastewater treatment: a research review].

PubMed

Zhu, Hong-tao; Wen, Xiang-hua; Huang, Xia

2009-01-01

As a high efficient water and wastewater treatment technology, membrane filtration has been mainly used in wastewater treatment as membrane bioreactor, in reclaiming secondary effluent,treating surface water and potable water, and etc. Membrane fouling is a main obstacle to the wide application of membrane technology. Ozone has strong oxidizing power and has been utilized widely in water and wastewater treatment. In recent years, researches on combined process of ozone-membrane filtration are increasing. This paper does reviews and analysis of these researches. It is noticed that there has been a few of researches on the ozone treatment plus MBR process. Pre-ozonation of feed to MBR and slight ozonation of the mixed liquid in MBR may be used to relieve membrane fouling.Combined processes of ozone-membrane filtration can be divided into three classes in terms of the function of ozone and the system configuration: (1) cleaning the fouled membrane with ozone; (2) separate ozone-membrane filtration process; (3) integrated ozone-membrane filtration process. Although most reports supported that ozonation can control membrane fouling development,there were contrary results. At present, researches on the mechanisms of ozone's effect on membrane fouling control concentrated on the change of organic composition of the filtration influent under ozonation, however, particulate substances, microbial and inorganic substances may also be affected and then play roles in membrane fouling, depending on source water quality and process configuration. Moreover, there have not been common parameters to evaluate the ozone diffusion equipment and efficiency. The authors suggest that further researches should emphasize on integrated ozone-membrane process, and more attention should be paid to the cost-effectiveness of the combined process.

A study on the reactivity characteristics of dissolved effluent organic matter (EfOM) from municipal wastewater treatment plant during ozonation.

PubMed

Jin, Pengkang; Jin, Xin; Bjerkelund, Viggo A; Østerhus, Stein W; Wang, Xiaochang C; Yang, Lei

2016-01-01

The reactivity of dissolved effluent organic matter (EfOM) in the process of ozonation was examined. Under different ozone dosages (0.42 ± 0.09, 0.98 ± 0.11 and 2.24 ± 0.17 mgO3/mg DOC), the EfOM before and after ozonation could be classified into four fractions according to their hydrophobicities. By ozonation, the hydrophobic fractions, especially hydrophobic acid (HOA) and hydrophobic neutral (HON), were found to undergo a process of transformation into hydrophilic fractions (HI), of which the HOA were first transformed into HON, and then the majority of the HON fraction was later converted to HI by further ozonation. It was noticeable that after ozonation, the fluorescence intensity in the humic-like and protein-like regions decreased as indicated by the excitation and emission matrix (EEM) spectra for the hydrophobic fractions. By coupling the EEM spectra with the molecular size analysis using high performance size exclusion chromatography (HPSEC), the difference between the characteristic distributions of the humic-like and protein-like fluorophores were further revealed. It could thus be extrapolated that ozone might have preferentially reacted with the protein-like hydrophobic fraction with molecular weight (MW) less than 100 kDa. Moreover, by X-ray photoelectron spectroscopy (XPS) analysis, it was identified that with increasing ozone dosage (from 0 to 2.24 ± 0.17 mgO3/mg DOC), the aromaticity of HON decreased dramatically, while aliphatics and ketones increased especially at the low ozone dose (0.42 ± 0.09 mgO3/mg DOC). Of the EfOM fractions, the HON fraction would have a higher content of electron enriched aromatics which could preferentially react with ozone rather than the HOA fraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Noninvasive determination of respiratory ozone absorption: development of a fast-responding ozone analyzer.

PubMed

Ultman, J S; Ben-Jebria, A

1991-03-01

We developed a chemiluminescent ozone analyzer and constructed an ozone bolus generator with the eventual goal of using a bolus-response method to measure noninvasively the longitudinal distribution of ozone absorption in human lungs. Because the analyzer will be used to sample gases within a single breath, it must have a sufficiently rapid response to monitor changes in ozone concentration during a four-second breathing period, yet its sampling flow must be small enough that it does not interfere with quiet respiratory flows of 300 mL/sec. Our analyzer, which is based on the chemiluminescent reaction between 2-methyl-2-butene and ozone, has favorable performance characteristics: a 90 percent step-response time of 110 msec; a linear calibration from 0.03 to 10 parts per million (ppm)2 with a sensitivity of 2.3 nA/ppm; a signal-to-noise ratio of 30 evaluated at 0.5 ppm; and a minimum detection limit of 0.017 ppm. At an airflow corresponding to quiet breathing, the ozone generator is capable of producing single boluses with a peak ozone fraction as high as 4 ppm, but containing only 0.35 micrograms of ozone dispersed over a small volume of 19 mL. To test the combination of ozone analyzer and bolus generator, we performed bolus-response experiments at steady airflows of 50 to 200 mL/sec in excised pig and sheep tracheas. In spite of the small surface area available for radial diffusion, we found that 25 to 50 percent of the ozone introduced into the trachea was absorbed. By comparing the mathematical moments of the bolus input and the response curves to the predictions of a diffusion theory, we computed an absorption coefficient (K). The values of K increased with increasing airflow, implying that ozone absorption is limited by diffusion processes in the airway lumen as well as in the surrounding tissue.

On the Climate Impacts of Upper Tropospheric and Lower Stratospheric Ozone

NASA Astrophysics Data System (ADS)

Xia, Yan; Huang, Yi; Hu, Yongyun

2018-01-01

The global warming simulations of the general circulation models (GCMs) are generally performed with different ozone prescriptions. We find that the differences in ozone distribution, especially in the upper tropospheric and lower stratospheric (UTLS) region, account for important model discrepancies shown in the ozone-only historical experiment of the Coupled Model Intercomparison Project Phase 5 (CMIP5). These discrepancies include global high cloud fraction, stratospheric temperature, and stratospheric water vapor. Through a set of experiments conducted by an atmospheric GCM with contrasting UTLS ozone prescriptions, we verify that UTLS ozone not only directly radiatively heats the UTLS region and cools the upper parts of the stratosphere but also strongly influences the high clouds due to its impact on relative humidity and static stability in the UTLS region and the stratospheric water vapor due to its impact on the tropical tropopause temperature. These consequences strongly affect the global mean effective radiative forcing of ozone, as noted in previous studies. Our findings suggest that special attention should be paid to the UTLS ozone when evaluating the climate effects of ozone depletion in the 20th century and recovery in the 21st century. UTLS ozone difference may also be important for understanding the intermodel discrepancy in the climate projections of the CMIP6 GCMs in which either prescribed or interactive ozone is used.

Mechano-biological Coupling of Cellular Responses to Microgravity

NASA Astrophysics Data System (ADS)

Long, Mian; Wang, Yuren; Zheng, Huiqiong; Shang, Peng; Duan, Enkui; Lü, Dongyuan

2015-11-01

Cellular response to microgravity is a basic issue in space biological sciences as well as space physiology and medicine. It is crucial to elucidate the mechano-biological coupling mechanisms of various biological organisms, since, from the principle of adaptability, all species evolved on the earth must possess the structure and function that adapts their living environment. As a basic element of an organism, a cell usually undergoes mechanical and chemical remodeling to sense, transmit, transduce, and respond to the alteration of gravitational signals. In the past decades, new computational platforms and experimental methods/techniques/devices are developed to mimic the biological effects of microgravity environment from the viewpoint of biomechanical approaches. Mechanobiology of plant gravisensing in the responses of statolith movements along the gravity vector and the relevant signal transduction and molecular regulatory mechanisms are investigated at gene, transcription, and protein levels. Mechanotransduction of bone or immune cell responses and stem cell development and tissue histogenesis are elucidated under microgravity. In this review, several important issues are briefly discussed. Future issues on gravisensing and mechanotransducing mechanisms are also proposed for ground-based studies as well as space missions.

Observed and theoretical variations of atmospheric ozone

NASA Technical Reports Server (NTRS)

London, J.

1976-01-01

Results are summarized from three areas of ozone research: (1) continued analysis of the global distribution of total ozone to extend the global ozone atlas to summarize 15 years (1957-72) of ground based observations; (2) analysis of balloon borne ozonesonde observations for Arosa, Switzerland, and Hohenpeissenberg, Germany (GFR); (3) contined processing of the (Orbiting Geophysical Observatory-4) satellite data to complete the analysis of the stratospheric ozone distribution from the available OGO-4 data. Results of the analysis of the total ozone observations indicated that the long term ozone variation have marked regional patterns and tend to alternate with season and hemisphere. It is becoming increasingly clear that these long period changes are associated with large scale variations in the general upper atmosphere circulation patterns.

Investigation of olive mill wastewater (OMW) ozonation efficiency with the use of a battery of selected ecotoxicity and human toxicity assays.

PubMed

Siorou, Sofia; Vgenis, Theodoros T; Dareioti, Margarita A; Vidali, Maria-Sophia; Efthimiou, Ioanna; Kornaros, Michael; Vlastos, Dimitris; Dailianis, Stefanos

2015-07-01

The effects of olive mill wastewater (OMW) on a battery of biological assays, before and during the ozonation process, were investigated in order to assess ozone's efficiency in removing phenolic compounds from OMW and decreasing the concomitant OMW toxicity. Specifically, ozonated-OMW held for 0, 60, 120, 300, 420, 540min in a glass bubble reactor, showed a drastic reduction of OMW total phenols (almost 50%) after 300min of ozonation with a concomitant decrease of OMW toxicity. In particular, the acute toxicity test primarily performed in the fairy shrimp Thamnocephalus platyurus (Thamnotoxkit F™ screening toxicity test) showed a significant attenuation of OMW-induced toxic effects, after ozonation for a period of 120 and in a lesser extent 300min, while further treatment resulted in a significant enhancement of ozonated-OMW toxic effects. Furthermore, ozonated-OMW-treated mussel hemocytes showed a significant attenuation of the ability of OMW to cause cytotoxic (obtained by the use of NRRT assay) effects already after an ozonation period of 120 and to a lesser extent 300min. In accordance with the latter, OMW-mediated oxidative (enhanced levels of superoxide anions and lipid peroxidation by-products) and genotoxic (induction of DNA damage) effects were diminished after OMW ozonation for the aforementioned periods of time. The latter was also revealed by the use of cytokinesis block micronucleus (CBMN) assay in human lymphocytes exposed to different concentrations of both raw- and ozonated-OMW for 60, 120 and 300min. Those findings revealed for a first time the existence of a critical time point during the OMW ozonation process that could be fundamentally used for evaluating OMW ozonation as a pretreatment method of OMW. Copyright © 2015 Elsevier B.V. All rights reserved.

Lidar Measurements of Ozone, Aerosols, and Clouds Observed in the Tropics Near Central America During TC4-Costa Rica

NASA Astrophysics Data System (ADS)

Hair, J. W.; Browell, E.; Butler, C.; Fenn, M.; Notari, A.; Simpson, S.; Ismail, S.; Avery, M.

2007-12-01

Large-scale measurements of ozone and aerosol distributions were made from the NASA DC-8 aircraft during the TC4 (Tropical Composition, Cloud, and Climate Coupling) field experiment conducted from June 28 - August 10, 2007 based in San Jose, Costa Rica. Remote measurements were made with an airborne lidar to provide ozone and multiple-wavelength aerosol and cloud backscatter profiles from near the surface to above the tropopause along the flight track. Aerosol depolarization measurements were also made for the detection of nonspherical aerosols, such as mineral dust, biomass burning, and recent emissions from South American volcanoes. Long-range transport of Saharan dust with depolarizing aerosols was frequently observed in the lower troposphere both over the Caribbean Sea and Pacific Ocean and within the marine boundary layer. In addition, visible and sub-visible cirrus clouds were observed with the multi-wavelength backscatter and depolarization measurements. Initial distributions of ozone, aerosol, and cloud are presented which will be used to interpret large-scale atmospheric processes. In situ measurements of ozone and aerosols made onboard the DC-8 will be compared to the remote lidar measurements. This paper provides a first look at the characteristics of ozone, aerosol, and cloud distributions that were encountered during this field experiment and provide a unique dataset that will be further related through satellite data, backward trajectories, and chemical transport models (CTM) to sources and sinks of ozone, aerosols, and clouds and to dynamical, chemical, and radiative processes.

A New SBUV Ozone Profile Time Series

NASA Technical Reports Server (NTRS)

McPeters, Richard

2011-01-01

Under NASA's MEaSUREs program for creating long term multi-instrument data sets, our group at Goddard has re-processed ozone profile data from a series of SBUV instruments. We have processed data from the Nimbus 7 SBUV instrument (1979-1990) and data from SBUV/2 instruments on NOAA-9 (1985-1998), NOAA-11 (1989-1995), NOAA-16 (2001-2010), NOAA-17 (2002-2010), and NOAA-18 (2005-2010). This reprocessing uses the version 8 ozone profile algorithm but now uses the Brion, Daumont, and Malicet (BMD) ozone cross sections instead of the Bass and Paur cross sections. The new cross sections have much better resolution, and extended wavelength range, and a more consistent temperature dependence. The re-processing also uses an improved cloud height climatology based on the Raman cloud retrievals of OMI. Finally, the instrument-to-instrument calibration is set using matched scenes so that ozone diurnal variation in the upper stratosphere does not alias into the ozone trands. Where there is no instrument overlap, SAGE and MLS are used to estimate calibration offsets. Preliminary analysis shows a more coherent time series as a function of altitude. The net effect on profile total column ozone is on average an absolute reduction of about one percent. Comparisons with ground-based systems are significantly better at high latitudes.

TREATMENT OF LANDFILL LEACHATE BY COUPLING COAGULATION-FLOCCULATION OR OZONATION TO GRANULAR ACTIVATED CARBON ADSORPTION.

PubMed

Oloibiri, Violet; Ufomba, Innocent; Chys, Michael; Audenaert, Wim; Demeestere, Kristof; Van Hulle, Stijn W H

2015-01-01

A major concern for landfilling facilities is the treatment of their leachate. To optimize organic matter removal from this leachate, the combination of two or more techniques is preferred in order to meet stringent effluent standards. In our study, coagulation-flocculation and ozonation are compared as pre- treatment steps for stabilized landfill leachate prior to granular activated carbon (GAC) adsorption. The efficiency of the pre treatment techniques is evaluated using COD and UVA254 measurements. For coagulation- flocculation, different chemicals are compared and optimal dosages are determined. After this, iron (III) chloride is selected for subsequent adsorption studies due to its high percentage of COD and UVA254 removal and good sludge settle-ability. Our finding show that ozonation as a single treatment is effective in reducing COD in landfill leachate by 66% compared to coagulation flocculation (33%). Meanwhile, coagulation performs better in UVA254 reduction than ozonation. Subsequent GAC adsorption of ozonated effluent, coagulated effluent and untreated leachate resulted in 77%, 53% and 8% total COD removal respectively (after 6 bed volumes). The effect of the pre-treatment techniques on GAC adsorption properties is evaluated experimentally and mathematically using Thomas and Yoon-Nelson models. Mathematical modelling of the experimental GAC adsorption data shows that ozonation increases the adsorption capacity and break through time with a factor of 2.5 compared to coagulation-flocculation.

Diclofenac removal from water with ozone and activated carbon.

PubMed

Beltrán, Fernando J; Pocostales, Pablo; Alvarez, Pedro; Oropesa, Ana

2009-04-30

Diclofenac (DCF) has been treated in water with ozone in the presence of various activated carbons. Activated carbon-free ozonation or single ozonation leads to a complete degradation of DCF in less than 15 min while in the presence of activated carbons higher degradation rates of TOC and DCF are noticeably achieved. Among the activated carbons used, P110 Hydraffin was found the most suitable for the catalytic ozonation of DCF. The influence of pH was also investigated. In the case of the single ozonation the increasing pH slightly increases the TOC removal rate. This effect, however, was not so clear in the presence of activated carbons where the influence of the adsorption process must be considered. Ecotoxicity experiments were performed, pointing out that single ozonation reduces the toxicity of the contaminated water but catalytic ozonation improved those results. As far as kinetics is concerned, DCF is removed with ozone in a fast kinetic regime and activated carbon merely acts as a simple adsorbent. However, for TOC removal the ozonation kinetic regime becomes slow. In the absence of the adsorbent, the apparent rate constant of the mineralization process was determined at different pH values. On the other hand, determination of the rate constant of the catalytic reaction over the activated carbon was not possible due to the effect of mass transfer resistances that controlled the process rate at the conditions investigated.

Temporal processes that contribute to nonlinearity in vegetation responses to ozone exposure and dose

Treesearch

Robert L. Heath; Allen S. Lefohn; Robert C. Musselman

2009-01-01

Ozone interacts with plant tissue through distinct temporal processes. Sequentially, plants are exposed to ambient O3 hat (1) moves through the leaf boundary layer, (2) is taken up into plant tissue primarily through stomata, and (3) undergoes chemical interaction within plant tissue, first by initiating alterations and then as part of plant...

Historical Tropospheric and Stratospheric Ozone Radiative Forcing Using the CMIP6 Database

NASA Astrophysics Data System (ADS)

Checa-Garcia, Ramiro; Hegglin, Michaela I.; Kinnison, Douglas; Plummer, David A.; Shine, Keith P.

2018-04-01

We calculate ozone radiative forcing (RF) and stratospheric temperature adjustments for the period 1850-2014 using the newly available Coupled Model Intercomparison Project phase 6 (CMIP6) ozone data set. The CMIP6 total ozone RF (1850s to 2000s) is 0.28 ± 0.17 W m-2 (which is 80% higher than our CMIP5 estimation), and 0.30 ± 0.17 W m-2 out to the present day (2014). The total ozone RF grows rapidly until the 1970s, slows toward the 2000s, and shows a renewed growth thereafter. Since the 1990s the shortwave RF exceeds the longwave RF. Global stratospheric ozone RF is positive between 1930 and 1970 and then turns negative but remains positive in the Northern Hemisphere throughout. Derived stratospheric temperature changes show a localized cooling in the subtropical lower stratosphere due to tropospheric ozone increases and cooling in the upper stratosphere due to ozone depletion by more than 1 K already prior to the satellite era (1980) and by more than 2 K out to the present day (2014).

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

The effect of ozone on the yellowing process of magnesium-deficient clonal Norway spruce grown under defined conditions.

PubMed

Siefermann-Harms, Dorothea; Payer, Hans Dieter; Schramel, Peter; Lütz, Cornelius

2005-02-01

During two vegetation periods, young clonal spruce trees (Picea abies (L.) Karst.) with sufficient and poor magnesium (Mg) supply were exposed in the environmental chambers of the GSF phytotron to three levels of ozone (daily means: 18-22, 88-130, and 135-190 microg m(-3); 10% reduction at night). Previous year's needles were examined at 4-week intervals with respect to their contents of Mg, Ca, K, Mn, N, P, and chlorophyll (Chl), various parameters of Chl fluorescence, and the stability of the isolated light-harvesting Chl-a/b-protein complex LHC II. The needles of the two nutrition variants contained more than 0.53 or less than 0.27mg Mg g(-1) needle dry matter, respectively. The ratio of variable to maximal Chl-a fluorescence of the dark-adapted needles, Fv/Fm, and the photoinhibitory quenching of Fv after light treatment, SVi.v, were affected by the Mg content of the needles rather than the ozone levels. Changes of the Chl content and the behavior of the LHC II allowed differentiating between a slow process of needle yellowing occurring under Mg deficiency only, and a rapid process of needle yellowing occurring under the combined action of Mg deficiency and ozone pollution. Only the rapid yellowing process was accompanied by destabilization of the LHC II, and the degree of destabilization was correlated with the ozone concentration present in the days before sampling. The results are consistent with observations obtained at a research site in the Central Black Forest (J Plant Physiol 161 (2004) 423).

Information content of ozone retrieval algorithms

NASA Technical Reports Server (NTRS)

Rodgers, C.; Bhartia, P. K.; Chu, W. P.; Curran, R.; Deluisi, J.; Gille, J. C.; Hudson, R.; Mateer, C.; Rusch, D.; Thomas, R. J.

1989-01-01

The algorithms are characterized that were used for production processing by the major suppliers of ozone data to show quantitatively: how the retrieved profile is related to the actual profile (This characterizes the altitude range and vertical resolution of the data); the nature of systematic errors in the retrieved profiles, including their vertical structure and relation to uncertain instrumental parameters; how trends in the real ozone are reflected in trends in the retrieved ozone profile; and how trends in other quantities (both instrumental and atmospheric) might appear as trends in the ozone profile. No serious deficiencies were found in the algorithms used in generating the major available ozone data sets. As the measurements are all indirect in someway, and the retrieved profiles have different characteristics, data from different instruments are not directly comparable.

Polar Processes in a 50-year Simulation of Stratospheric Chemistry and Transport

NASA Technical Reports Server (NTRS)

Kawa, S.R.; Douglass, A. R.; Patrick, L. C.; Allen, D. R.; Randall, C. E.

2004-01-01

The unique chemical, dynamical, and microphysical processes that occur in the winter polar lower stratosphere are expected to interact strongly with changing climate and trace gas abundances. Significant changes in ozone have been observed and prediction of future ozone and climate interactions depends on modeling these processes successfully. We have conducted an off-line model simulation of the stratosphere for trace gas conditions representative of 1975-2025 using meteorology from the NASA finite-volume general circulation model. The objective of this simulation is to examine the sensitivity of stratospheric ozone and chemical change to varying meteorology and trace gas inputs. This presentation will examine the dependence of ozone and related processes in polar regions on the climatological and trace gas changes in the model. The model past performance is base-lined against available observations, and a future ozone recovery scenario is forecast. Overall the model ozone simulation is quite realistic, but initial analysis of the detailed evolution of some observable processes suggests systematic shortcomings in our description of the polar chemical rates and/or mechanisms. Model sensitivities, strengths, and weaknesses will be discussed with implications for uncertainty and confidence in coupled climate chemistry predictions.

Ozone

MedlinePlus

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

Removing PAHs from urban runoff water by combining ozonation and carbon nano-onions.

PubMed

Sakulthaew, Chainarong; Comfort, Steve D; Chokejaroenrat, Chanat; Li, Xu; Harris, Clifford E

2015-12-01

Ozone (O3) is a chemical oxidant capable of transforming polycyclic aromatic hydrocarbons (PAHs) in urban runoff within minutes but complete oxidation to CO2 can take days to weeks. We developed and tested a flow-through system that used ozone to quickly transform PAHs in a runoff stream and then removed the ozone-transformed PAHs via adsorption to carbon nano-onions (CNOs). To quantify the efficacy of this approach, (14)C-labeled phenanthrene and benzo(a)pyrene, as well as a mixture of 16 unlabeled PAHs were used as test compounds. These PAHs were pumped from a reservoir into a flow-through reactor that continuously ozonated the solution. Outflow from the reactor then went to a chamber that contained CNOs to adsorb the ozone-transformed PAHs and allowed clean water to pass. By adding a microbial consortium to the CNOs following adsorption, we observed that bacteria were able to degrade the adsorbed products and release more soluble, biodegradable products back into solution. Control treatments confirmed that parent PAH structures (i.e., non-ozonated) were not biologically degraded following CNO adsorption and that O3-transformed PAHs were not released from the CNOs in the absence of bacteria. These results support the combined use of ozone, carbon nano-onions with subsequent biological degradation as a means of removing PAHs from urban runoff or a commercial waste stream. Copyright © 2015 Elsevier Ltd. All rights reserved.

Advanced treatment of biotreated textile industry wastewater with ozone, virgin/ozonated granular activated carbon and their combination.

PubMed

Arslan-Alaton, Idil; Seremet, Ozden

2004-01-01

Biotreated textile wastewater (CODo = 248 mg L(-1); TOCo = 58 mg L(-1); A620 = 0.007 cm(-1); A525 = 0.181 cm(-1); A436 = 0.198 cm(-1)) was subjected to advanced treatment with ozonation, granular activated carbon (GAC) adsorption in serial and simultaneous applications. Experiments were conducted to investigate the effects of applied ozone dose, ozone absorption rate, specific ozone absorption efficiency, GAC dose, and reaction pH on the treatment performance of the selected tertiary treatment scheme. In separate experiments, the impact of virgin GAC ozonation on its adsorptive capacity for biotreated and biotreated + ozonated textile effluent was also investigated. Ozonation appeared to be more effective for decolorization (kd = 0.15 min(-1) at pH = 3), whereas GAC adsorption yielded higher COD removal rates (54% at pH = 3). It was also found that GAC addition (4 g/L) at pH = 7 and 9 enhanced the COD abatement rate of the ozonation process significantly and that the sequential application of ozonation (at pH = 3-11, 675 mg L(-1) O3) followed by GAC adsorption (at pH = 3-7, 10 g L(-1) GAC) resulted in the highest treatment performances both in terms of color and COD reduction. Simultaneous application of GAC and ozone at acidic and alkaline pH seriously inhibited COD abatement rates as a consequence of competitive adsorption and partial oxidation of textile components and GAC. It could also be established that ozone absorption efficiency decreased after color removal was complete. Ozonation of biotreated textile wastewater with 113 mg L(-1) ozone resulted in an appreciable enhancement of GAC adsorptive capacity in terms of residual color removal. Ozonation of GAC at relatively low doses (= 10.8 mg/g GAC) did not improve its overall adsorption capacity.

Growth and recovery of zebrafish embryos after developmental exposure to raw and ozonated oil sands process-affected water.

PubMed

Lyons, Danielle D; Morrison, Christie; Philibert, Danielle A; Gamal El-Din, Mohamed; Tierney, Keith B

2018-05-07

Due to the increasing volume of oil sands process-affect water (OSPW) and its toxicity to aquatic organisms, it is important to fully understand its effects and study remediation processes that will enable its release to the environment. Ozone treatment is currently being considered as a tool to expedite remediation, as it is known to degrade toxic organic compounds present in OSPW. In this study, we aimed to measure the effects of OSPW exposure on the growth, development and recovery of zebrafish (Danio rerio) embryos. We also used ozone-treated OSPW to determine whether ozonation negated any effects of raw OSPW exposure. As biomarkers of exposure, we assessed the expression of genes involved in neurodevelopment (ngn1, neuroD), estrogenicity (vtg), oxidative stress (sod1), and biotransformation (cyp1a, cyp1b). Our study found that exposure to both raw and ozonated OSPW did not impair growth of zebrafish embryos, however, otoliths of exposed embryos were smaller than those of control embryos. The expression levels of both cyp1a and cyp1b were induced by raw OSPW exposure. However, after the exposure period, expression levels of these genes returned to control levels within two days of residence in clean water. We found no changes in the expression levels of ngn1, neuroD and vtg genes with exposure to treated or untreated OSPW. Overall, our study found that raw OSPW exposure did not have many negative effects on zebrafish embryos and embryos appeared to recover relatively quickly after exposure ended. Furthermore, ozone treatment decreased the induction of cyp1a and cyp1b. Copyright © 2018 Elsevier Ltd. All rights reserved.

The usefulness of ozone treatment in spinal pain

PubMed Central

Bocci, Velio; Borrelli, Emma; Zanardi, Iacopo; Travagli, Valter

2015-01-01

Objective The aim of this review is to elucidate the biochemical, molecular, immunological, and pharmaceutical mechanisms of action of ozone dissolved in biological fluids. Studies performed during the last two decades allow the drawing of a comprehensive framework for understanding and recommending the integration of ozone therapy for spinal pain. Methods An in-depth screening of primary sources of information online – via SciFinder Scholar, Google Scholar, and Scopus databases as well as Embase, PubMed, and the Cochrane Database of Systemic Reviews – was performed. In this review, the most significant papers of the last 25 years are presented and their proposals critically evaluated, regardless of the bibliometric impact of the journals. Results The efficacy of standard treatments combined with the unique capacity of ozone therapy to reactivate the innate antioxidant system is the key to correcting the oxidative stress typical of chronic inflammatory diseases. Pain pathways and control systems of algesic signals after ozone administration are described. Conclusion This paper finds favors the full insertion of ozone therapy into pharmaceutical sciences, rather than as either an alternative or an esoteric approach. PMID:26028964

Liquid-phase study of ozone inactivation of Venezuelan equine encephalomyelitis virus.

PubMed Central

Akey, D H; Walton, T E

1985-01-01

Ozone, in a liquid-phase application, was evaluated as a residue-free viral inactivant that may be suitable for use in an arboviral research laboratory. Commonly used sterilizing agents may leave trace residues, be flammable or explosive, and require lengthy periods for gases or residues to dissipate after decontamination of equipment such as biological safety cabinets. Complete liquid-phase inactivation of Venezuelan equine encephalomyelitis virus was attained at 0.025 mg of ozone per liter within 45 min of exposure. The inactivation of 10(6.5) median cell culture infective doses (CCID50 of Venezuelan equine encephalomyelitis virus per milliliter represented a reduction of 99.99997% of the viral particles from the control levels of 10(7.25-7.5) CCID50/ml. A dose-response relationship was demonstrated. Analysis by polynomial regression of the logarithmic values for both ozone concentrations and percent reduction of viral titers had a highly significant r2 of 0.8 (F = 63.6; df = 1, 16). These results, together with those of Akey (J. Econ. Entomol. 75:387-392, 1982) on the use of ozone to kill a winged arboviral vector, indicate that ozone is a promising candidate as a sterilizing agent in some applications for biological safety cabinets and other equipment used in vector studies with arboviruses. PMID:4083884

Removal of oxalic acid, oxamic acid and aniline by a combined photolysis and ozonation process.

PubMed

Orge, C A; Faria, J L; Pereira, M F R

2015-01-01

Aniline (ANL), an aromatic amine, oxalic acid (OXA) and oxamic acid (OMA), short-chain carboxylic acids, were chosen as model organic pollutants for testing the combined effect of neat photolysis and ozonation in the treatment of aqueous effluents. In order to better understand the results, single ozonation and neat photolysis were also carried out. OXA has a high refractory character relatively to single ozonation and neat photolysis only accounted for 26% conversion of OXA after 2 h of reaction. On the other hand, OXA complete degradation was observed in less than an hour when ozone and light were used simultaneously. Despite OMA, a compound never studied before by a combined ozonation and photolysis treatment, being highly refractory to oxidation, more than 50% was removed by photo-ozonation after 3 h of reaction. In the case of ANL, both single ozonation and photo-ozonation resulted in 100% removal in a short reaction period due to the high reactivity of ozone to attack this type of molecules; however, only the combined method leads to efficient mineralization (89%) after 3 h of reaction. A significant synergetic effect was observed in the degradation of the selected contaminants by the simultaneous use of ozone and light, since the mineralization rate of combined method is higher than the sum of the mineralization rates of the individual treatments. The promising results observed in the degradation of the selected contaminants are paving the way to the application of photo-ozonation in the treatment of wastewater containing this type of pollutants.

16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It is... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim...

16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It is... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim...

Antarctic Climate Variability: Covariance of Ozone and Sea Ice in Atmosphere - Ocean Coupled Model Simulations

NASA Astrophysics Data System (ADS)

Jrrar, Amna; Abraham, N. Luke; Pyle, John A.; Holland, David

2014-05-01

Changes in sea ice significantly modulate climate change because of its high reflective and insulating nature. While Arctic Sea Ice Extent (SIE) shows a negative trend. Antarctic SIE shows a weak but positive trend, estimated at 0.127 x 106 km2 per decade. The trend results from large regional cancellations, more ice in the Weddell and the Ross seas, and less ice in the Amundsen - Bellingshausen seas. A number of studies had demonstrated that stratospheric ozone depletion has had a major impact on the atmospheric circulation, causing a positive trend in the Southern Annular Mode (SAM), which has been linked to the observed positive trend in autumn sea ice in the Ross Sea. However, other modelling studies show that models forced with prescribed ozone hole simulate decreased sea ice in all regions comparative to a control run. A recent study has also shown that stratospheric ozone recovery will mitigate Antarctic sea ice loss. To verify this assumed relationship, it is important first to investigate the covariance between ozone's natural (dynamical) variability and Antarctic sea ice distribution in pre-industrial climate, to estimate the trend due to natural variability. We investigate the relationship between anomalous Antarctic ozone years and the subsequent changes in Antarctic sea ice distribution in a multidecadal control simulation using the AO-UMUKCA model. The model has a horizontal resolution of 3.75 X 2.5 degrees in longitude and latitude; and 60 hybrid height levels in the vertical, from the surface up to a height of 84 km. The ocean component is the NEMO ocean model on the ORCA2 tripolar grid, and the sea ice model is CICE. We evaluate the model's performance in terms of sea ice distribution, and we calculate sea ice extent trends for composites of anomalously low versus anomalously high SH polar ozone column. We apply EOF analysis to the seasonal anomalies of sea ice concentration, MSLP, and Z 500, and identify the leading climate modes controlling the

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Measurements of upward turbulent ozone fluxes above a subalpine spruce-fir forest

Treesearch

Karl Zeller; Ted Hehn

1996-01-01

High rural concentrations of ozone (O3) are thought to be either stratospheric in origin, advected from upwind urban sources, or photochemically generated locally as a result of natural trace gas emissions. Ozone is known to be transported vertically downward from the above-canopy atmospheric surface layer and destroyed within stomata or on other biological and mineral...

Consumer acceptance of ozone-treated whole shell eggs.

PubMed

Kamotani, Setsuko; Hooker, Neal; Smith, Stephanie; Lee, Ken

2010-03-01

Ozone-based processing is a novel technology with potentially fewer adverse effects than in-shell thermal pasteurization of eggs. There are no consumer acceptance studies published on ozone-treated eggs. This study examines consumers' ability to detect changes between ozone-treated, thermal-treated, and fresh untreated eggs. Consumers (n = 111) evaluated visual attributes of uncooked eggs and a separate group of consumers (n = 132) evaluated acceptability of cooked eggs. Consumers evaluated attribute intensity of the eggs. The yolks and albumens of the thermal-treated and ozone-treated eggs were perceived to be significantly cloudier than the untreated control, while the ozone-treated eggs were more similar to control (P < 0.05). The yolks of ozone-treated eggs were perceived to have significantly lower heights and greater spreads than the others (P < 0.05). Despite these perceptions, overall visual appeal of ozone-treated eggs was not significantly different from control eggs. A separate set of consumers used hedonic scales to evaluate overall liking, appearance, aroma, flavor, and texture of cooked eggs. Just-about-right (JAR) scales were used to rate the color, moistness, and texture. There were no differences on any attribute scores between the treatments, except thermal-treated and ozone-treated were perceived as less moist than the control. There were no adverse effects on consumer acceptance of eggs, treated with ozone, with acceptance the same as an untreated control. These findings are useful as ozone pasteurization can enhance the safety of fresh shell eggs to meet the goals of the U.S. Egg Safety Action Plan. The U.S. Egg Safety Action Plan requires all shell eggs to be pasteurized to prevent foodborne illness. Heat pasteurization partially cooks the egg, so an alternative process uses ozone with less heat. This study shows the ozone pasteurization has no detectable sensory defects.

Foreign and Domestic Contributions to Springtime Ozone Pollution over China

NASA Astrophysics Data System (ADS)

Ni, R.; Lin, J.; Yan, Y.; Lin, W.; Chen, H.

2017-12-01

Ozone is a critical air pollutant that damages human health and vegetation. Previous studies for the United States and Europe have shown large influences of foreign emissions on domestic ozone levels, whereas the relative contributions of foreign versus domestic emissions are much less clear for China. Here, we use a global-regional two-way coupled model system based on GEOS-Chem to quantify the contributions to springtime ozone over China from anthropogenic emissions in major source regions across the globe. Our results indicate considerable influences of foreign anthropogenic pollution on China's ozone pollution. Together, foreign anthropogenic emissions enhance springtime surface ozone over China by 3 12 ppb. Of all ozone over China produced by global anthropogenic emissions, foreign emissions contribute 40% near the surface, and the contribution increases with altitude until a value of 80% in the upper troposphere. Impact from Japan and Korea is 1 2 ppb over east coastal regions, and negligible in inland. Anthropogenic emissions of South and South-East Asia increase ozone over Tibet and the Yunnan-Guizhou Plateau by up to 5 ppb, and their contribution increases with height due to strong vertical transport. Pollution from North America and Europe mainly accompanies strong westerly winds and frequent cyclonic activities that are favorable to long-range transport. European anthropogenic pollution enhances surface ozone by 1 3 ppb over West and North China. Despite a much longer transport distance, the contribution from North America is greater than European contribution due to the nearly doubled amount of anthropogenic NMVOC emissions. The high percentage contribution of foreign anthropogenic emissions to China's ozone pollution can be partly explained by excessive domestic NOx emissions that suppress ozone production efficiency and even destroy ozone. Our study is relevant to Chinese ozone pollution control and global environmental protection collaboration.

Aerosol indirect effect on tropospheric ozone via lightning

NASA Astrophysics Data System (ADS)

Yuan, Tianle; Remer, Lorraine A.; Bian, Huisheng; Ziemke, Jerald R.; Albrecht, Rachel; Pickering, Kenneth E.; Oreopoulos, Lazaros; Goodman, Steven J.; Yu, Hongbin; Allen, Dale J.

2012-09-01

Tropospheric ozone (O3) is a pollutant and major greenhouse gas and its radiative forcing is still uncertain. Inadequate understanding of processes related to O3 production, in particular those natural ones such as lightning, contributes to this uncertainty. Here we demonstrate a new effect of aerosol particles on O3production by affecting lightning activity and lightning-generated NOx (LNOx). We find that lightning flash rate increases at a remarkable rate of 30 times or more per unit of aerosol optical depth. We provide observational evidence that indicates the observed increase in lightning activity is caused by the influx of aerosols from a volcano. Satellite data analyses show O3is increased as a result of aerosol-induced increase in lightning and LNOx, which is supported by modle simulations with prescribed lightning change. O3production increase from this aerosol-lightning-ozone link is concentrated in the upper troposphere, where O3 is most efficient as a greenhouse gas. In the face of anthropogenic aerosol increase our findings suggest that lightning activity, LNOx and O3, especially in the upper troposphere, have all increased substantially since preindustrial time due to the proposed aerosol-lightning-ozone link, which implies a stronger O3 historical radiative forcing. Aerosol forcing therefore has a warming component via its effect on O3 production and this component has mostly been ignored in previous studies of climate forcing related to O3and aerosols. Sensitivity simulations suggest that 4-8% increase of column tropospheric ozone, mainly in the tropics, is expected if aerosol-lighting-ozone link is parameterized, depending on the background emission scenario. We note, however, substantial uncertainties remain on the exact magnitude of aerosol effect on tropospheric O3 via lightning. The challenges for obtaining a quantitative global estimate of this effect are also discussed. Our results have significant implications for understanding past and

Biologically active filters - An advanced water treatment process for contaminants of emerging concern.

PubMed

Zhang, Shuangyi; Gitungo, Stephen W; Axe, Lisa; Raczko, Robert F; Dyksen, John E

2017-05-01

With the increasing concern of contaminants of emerging concern (CECs) in source water, this study examines the hypothesis that existing filters in water treatment plants can be converted to biologically active filters (BAFs) to treat these compounds. Removals through bench-scale BAFs were evaluated as a function of media, granular activated carbon (GAC) and dual media, empty bed contact time (EBCT), and pre-ozonation. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater dissolved organic carbon removal normalized to adenosine triphosphate (ATP) were observed indicating increased microbial activity as compared to anthracite/sand dual media BAFs. ATP concentrations in the upper portion of the BAFs were as much as four times greater than the middle and lower portions of the dual media and 1.5 times greater in GAC. Sixteen CECs were spiked in the source water. At an EBCT of 18 min (min), GAC BAFs were highly effective with overall removals greater than 80% without pre-ozonation; exceptions included tri(2-chloroethyl) phosphate and iopromide. With a 10 min EBCT, the degree of CECs removal was reduced with less than half of the compounds removed at greater than 80%. The dual media BAFs showed limited CECs removal with only four compounds removed at greater than 80%, and 10 compounds were reduced by less than 50% with either EBCT. This study demonstrated that GAC BAFs with and without pre-ozonation are an effective and advanced technology for treating emerging contaminants. On the other hand, pre-ozonation is needed for dual media BAFs to remove CECs. The most cost effective operating conditions for dual media BAFs were a 10 min EBCT with the application of pre-ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coupling dry deposition to vegetation phenology in the Community Earth System Model: Implications for the simulation of surface O3

NASA Astrophysics Data System (ADS)

Val Martin, M.; Heald, C. L.; Arnold, S. R.

2014-04-01

Dry deposition is an important removal process controlling surface ozone. We examine the representation of this ozone loss mechanism in the Community Earth System Model. We first correct the dry deposition parameterization by coupling the leaf and stomatal vegetation resistances to the leaf area index, an omission which has adversely impacted over a decade of ozone simulations using both the Model for Ozone and Related chemical Tracers (MOZART) and Community Atmospheric Model-Chem (CAM-Chem) global models. We show that this correction increases O3 dry deposition velocities over vegetated regions and improves the simulated seasonality in this loss process. This enhanced removal reduces the previously reported bias in summertime surface O3 simulated over eastern U.S. and Europe. We further optimize the parameterization by scaling down the stomatal resistance used in the Community Land Model to observed values. This in turn further improves the simulation of dry deposition velocity of O3, particularly over broadleaf forested regions. The summertime surface O3 bias is reduced from 30 ppb to 14 ppb over eastern U.S. and 13 ppb to 5 ppb over Europe from the standard to the optimized scheme, respectively. O3 deposition processes must therefore be accurately coupled to vegetation phenology within 3-D atmospheric models, as a first step toward improving surface O3 and simulating O3 responses to future and past vegetation changes.

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

PubMed

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

2015-05-01

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. © 2014 Wiley Periodicals, Inc.

A Review of Microbubble and its Applications in Ozonation

NASA Astrophysics Data System (ADS)

Shangguan, Yufei; Yu, Shuili; Gong, Chao; Wang, Yue; Yang, Wangzhen; Hou, Li-an

2018-03-01

Ozonation has been demonstrated to be an effective technology for the oxidation of organic matters in water treatment. But the low solubility and low mass transfer efficiency limit the application. Microbubble technology has the potential of enhancing gas-liquid mass transfer efficiency, thus it can be applied in ozonation process. The applications of microbubble ozonation have shown advantages over macro bubble ozonation in mass transfer and reaction rate. Microbubble ozonation will be a promising treatment both in water and wastewater treatment.

Sterilization of Microorganisms by Ozone and Ultrasound

NASA Astrophysics Data System (ADS)

Krasnyj, V. V.; Klosovskij, A. V.; Panasko, T. A.; Shvets, O. M.; Semenova, O. T.; Taran, V. S.; Tereshin, V. I.

2008-03-01

The results of recent experimental methods of sterilization of microorganisms with the use of ozone and ultrasound are presented. The main aim was to optimize the process of sterilization in water solution taking into account the ozone concentration, the power of ultrasonic emitter and the temperature of water. In the present work, the ultrasonic cavitation with simultaneous ozone generation has been used. The high ozone concentration in water solution was achieved by two-barrier glow discharge generated at atmospheric pressure and a cooling thermo-electric module. Such a sterilizer consists of ozone generator in a shape of flat electrodes covered with dielectric material and a high-voltage pulsed power supply of 250 W. The sterilization camera was equipped with ultrasonic source operated at 100 W. The experiments on the inactivation of bacteria of the Bacillus Cereus type were carried out in the distilled water saturated by ozone. The ozone concentration in the aqueous solution was 10 mg/1, whereas the ozone concentration at the output of ozone generator was 30 mg/1. The complete inactivation of spores took 15 min. Selection of the temperature of water, the ozone concentrations and ultrasonic power allowed to determine the time necessary for destroying the row of microorganisms.

Fate of return activated sludge after ozonation: an optimization study for sludge disintegration.

PubMed

Demir, Ozlem; Filibeli, Ayse

2012-09-01

The effects of ozonation on sludge disintegration should be investigated before the application of ozone during biological treatment, in order to minimize excess sludge production. In this study, changes in sludge and supernatant after ozonation of return activated sludge were investigated for seven different ozone doses. The optimum ozone dose to avoid inhibition of ozonation and high ozone cost was determined in terms of disintegration degree as 0.05 g O3/gTS. Suspended solid and volatile suspended solid concentrations of sludge decreased by 77.8% and 71.6%, respectively, at the optimum ozone dose. Ozonation significantly decomposed sludge flocs. The release of cell contents was proved by the increase of supernatant total nitrogen (TN) and phosphorus (TP). While TN increased from 7 mg/L to 151 mg/L, TP increased from 8.8 to 33 mg/L at the optimum ozone dose. The dewaterability and filterability characteristics of the ozonated sludge were also examined. Capillary suction time increased with increasing ozone dosage, but specific resistance to filtration increased to a specific value and then decreased dramatically. The particle size distribution changed significantly as a result of floc disruption at an optimum dose of 0.05 gO3/gTS.

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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

2015-05-06

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

Ozone Lidar Observations for Air Quality Studies

NASA Technical Reports Server (NTRS)

Wang, Lihua; Newchurch, Mike; Kuang, Shi; Burris, John F.; Huang, Guanyu; Pour-Biazar, Arastoo; Koshak, William; Follette-Cook, Melanie B.; Pickering, Kenneth E.; McGee, Thomas J.;

Effects of ozone and ozone/peroxide on trace organic contaminants and NDMA in drinking water and water reuse applications.

PubMed

Pisarenko, Aleksey N; Stanford, Benjamin D; Yan, Dongxu; Gerrity, Daniel; Snyder, Shane A

2012-02-01

An ozone and ozone/peroxide oxidation process was evaluated at pilot scale for trace organic contaminant (TOrC) mitigation and NDMA formation in both drinking water and water reuse applications. A reverse osmosis (RO) pilot was also evaluated as part of the water reuse treatment train. Ozone/peroxide showed lower electrical energy per order of removal (EEO) values for TOrCs in surface water treatment, but the addition of hydrogen peroxide increased EEO values during wastewater treatment. TOrC oxidation was correlated to changes in UV(254) absorbance and fluorescence offering a surrogate model for predicting contaminant removal. A decrease in N-nitrosodimethylamine (NDMA) formation potential (after chloramination) was observed after treatment with ozone and ozone/peroxide. However, during spiking experiments with surface water, ozone/peroxide achieved limited destruction of NDMA, while in wastewaters net direct formation of NDMA of 6-33 ng/L was observed after either ozone or ozone/peroxide treatment. Once formed during ozonation, NDMA passed through the subsequent RO membranes, which highlights the significance of the potential for direct NDMA formation during oxidation in reuse applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microphysical Modelling of the 1999-2000 Arctic Winter. 2; Chlorine Activation and Ozone Depletion

NASA Technical Reports Server (NTRS)

Drdla, K.; Schoeberl, M. R.; Gore, Warren J. (Technical Monitor)

2001-01-01

The effect of a range of assumptions about polar stratospheric clouds (PSCs) on ozone depletion has been assessed using at couple microphysical/photochemical model. The composition of the PSCs was varied (ternary solutions, nitric acid trihydrate, nitric acid dehydrate, or ice), as were parameters that affected the levels of denitrification and dehydration. Ozone depletion was affected by assumptions about PSC freezing because of the variability in resultant nitrification chlorine activation in all scenarios was similar despite the range of assumed PSC compositions. Vortex-average ozone loss exceeded 40% in the lower stratosphere for simulations without nitrification an additional ozone loss of 15-20% was possible in scenarios where vortex-average nitrification reached 60%. Ozone loss intensifies non-linearly with enhanced nitrification in air parcels with 90% nitrification 40% ozone loss in mid-April can be attributed to nitrification alone. However, these effects are sensitive to the stability of the vortex in springtime: nitrification only began to influence ozone depletion in mid-March.

Treatment of diazo dye C.I. Reactive Black 5 in aqueous solution by combined process of interior microelectrolysis and ozonation.

PubMed

Guo, Xiaoyan; Cai, Yaping; Wei, Zhongbo; Hou, Haifeng; Yang, Xi; Wang, Zunyao

2013-01-01

Interior microelectrolysis (IM) as a pretreatment process was effective to treat Reactive Black 5 (RB5) in this study. The removal rates of chemical oxygen demand (COD), total organic carbon (TOC) and color were 46.05, 39.99 and 98.77%, respectively, when this process was conducted under the following optimal conditions: the volumetric ratio between iron scraps and active carbon (AC) (V(Fe)/V(C)) 1.0, pH 2.0, aeration dosage 0.6 L/min, and reaction time 100 min. Contaminants could be further removed by ozonation. After subsequent ozonation for 200 min, the solution could be completely decolorized, and the COD and TOC removal rates were up to 77.78 and 66.51%, respectively. In addition, acute toxicity tests with Daphnia magna showed that pretreatment by IM generated effluents that were more toxic when compared with the initial wastewater, and the toxicity was reduced after subsequent ozonation.

Dynamic evaluation of two decades of WRF-CMAQ ozone ...

EPA Pesticide Factsheets

Dynamic evaluation of the fully coupled Weather Research and Forecasting (WRF)– Community Multi-scale Air Quality (CMAQ) model ozone simulations over the contiguous United States (CONUS) using two decades of simulations covering the period from 1990 to 2010 is conducted to assess how well the changes in observed ozone air quality are simulated by the model. The changes induced by variations in meteorology and/or emissions are also evaluated during the same timeframe using spectral decomposition of observed and modeled ozone time series with the aim of identifying the underlying forcing mechanisms that control ozone exceedances and making informed recommendations for the optimal use of regional-scale air quality models. The evaluation is focused on the warm season's (i.e., May–September) daily maximum 8-hr (DM8HR) ozone concentrations, the 4th highest (4th) and average of top 10 DM8HR ozone values (top10), as well as the spectrally-decomposed components of the DM8HR ozone time series using the Kolmogorov-Zurbenko (KZ) filter. Results of the dynamic evaluation are presented for six regions in the U.S., consistent with the National Oceanic and Atmospheric Administration (NOAA) climatic regions. During the earlier 11-yr period (1990–2000), the simulated and observed trends are not statistically significant. During the more recent 2000–2010 period, all trends are statistically significant and WRF-CMAQ captures the observed trend in most regions. Given large n

Tropical Tropospheric Ozone: New Insights from Remote Sensing and Field Studies

NASA Technical Reports Server (NTRS)

Thompson, Anne

1999-01-01

This talk will summarize our recent research in tropical tropospheric ozone studies in the field and from space. New tropospheric ozone and aerosol products from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument will be highlighted (Hudson and Thompson, 1998; Thompson and Hudson, 1999). These are suitable for studying processes like ozone pollution resulting from biomass fires, seasonal and interannual variations and trends. Archived maps of tropospheric ozone over the tropics, from the Nimbus 7 observing period (1979-1992) are available in digital form at our website. Real-time processing of TOMS data has produced images of tropical tropospheric ozone (TTO) since early 1997, using Earth-Probe TOMS; these maps are also available on the homepage.

Nadir Ozone Profile Retrieval from SCIAMACHY: application to the Antarctic Ozone Hole

NASA Astrophysics Data System (ADS)

Shah, Sweta; Piet, Stammes; Tuinder, Olaf N. E.; de Laat, Jos

2017-04-01

We present new nadir ozone profile retrievals using SCIAMACHY UV reflectance spectra for the mission period of the Envisat satellite. We have used the most recent Level-1 data version (v8 with degradation correction included) in the UV range (265-330 nm) and have used the OPERA optimal estimation algorithm (van Peet et al., AMT, 2014) developed in KNMI. We first show the comparison of the retrieved satellite profiles to co-located ozone sonde profiles in order to evaluate the accuracy of the retrieved ozone profile dataset. Based on these results, we have further processed the SCIAMCHY nadir dataset, specifically all the southern hemisphere pixels south of 45 degrees latitude for the months of August-November for the complete years 2003-2011. We show the monthly mean profiles, time-series of daily averages and minima of the retrieved stratospheric columns, and finally the ozone profile trend over the years 2003-2011. We also show the comparison of our results with the literature and hence the consistency of this new SCIAMACHY dataset.

Synergistic effect of ozonation and ionizing radiation for PVA decomposition.

PubMed

Sun, Weihua; Chen, Lujun; Zhang, Yongming; Wang, Jianlong

2015-08-01

Ozonation and ionizing radiation are both advanced oxidation processes (AOPs) without chemical addition and secondary pollution. Also, the two processes' efficiency is determined by different pH conditions, which creates more possibilities for their combination. Importantly, the combined process of ozonation and ionizing radiation could be suitable for treating wastewaters with extreme pH values, i.e., textile wastewater. To find synergistic effects, the combined process of ozonation and ionizing radiation mineralization was investigated for degradation of polyvinyl alcohol (PVA) at different pH levels. A synergistic effect was found at initial pH in the range 3.0-9.4. When the initial pH was 3.0, the combined process of ozonation and ionizing radiation gave a PVA mineralization degree of 17%. This was 2.7 times the sum achieved by the two individual processes, and factors of 2.1 and 1.7 were achieved at initial pH of 7.0 and 9.4, respectively. The combined process of ozonation and ionizing radiation was demonstrated to be a feasible strategy for treatment of PVA-containing wastewater. Copyright © 2015. Published by Elsevier B.V.

When eyes drive hand: Influence of non-biological motion on visuo-motor coupling.

PubMed

Thoret, Etienne; Aramaki, Mitsuko; Bringoux, Lionel; Ystad, Sølvi; Kronland-Martinet, Richard

2016-01-26

Many studies stressed that the human movement execution but also the perception of motion are constrained by specific kinematics. For instance, it has been shown that the visuo-manual tracking of a spotlight was optimal when the spotlight motion complies with biological rules such as the so-called 1/3 power law, establishing the co-variation between the velocity and the trajectory curvature of the movement. The visual or kinesthetic perception of a geometry induced by motion has also been shown to be constrained by such biological rules. In the present study, we investigated whether the geometry induced by the visuo-motor coupling of biological movements was also constrained by the 1/3 power law under visual open loop control, i.e. without visual feedback of arm displacement. We showed that when someone was asked to synchronize a drawing movement with a visual spotlight following a circular shape, the geometry of the reproduced shape was fooled by visual kinematics that did not respect the 1/3 power law. In particular, elliptical shapes were reproduced when the circle is trailed with a kinematics corresponding to an ellipse. Moreover, the distortions observed here were larger than in the perceptual tasks stressing the role of motor attractors in such a visuo-motor coupling. Finally, by investigating the direct influence of visual kinematics on the motor reproduction, our result conciliates previous knowledge on sensorimotor coupling of biological motions with external stimuli and gives evidence to the amodal encoding of biological motion. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Seasonal Variability in Tropospheric Ozone Distribution Over Qatar

NASA Astrophysics Data System (ADS)

Ayoub, Mohammed; Ackermann, Luis

2015-04-01

We report on the vertical distribution and seasonal variability in tropospheric ozone over the Middle East through one year of weekly ozonesondes launched from Doha, Qatar during 2014. A total of 49 2Z-V7 DMT/EN-SCI Electrochemical Concentration Cell (ECC) ozonesondes employing a 1% buffered potassium iodide solution (KI), coupled with iMet-1-RS GPS radiosondes were launched around 1300 local time. The authors used the SkySonde telemetry software (developed by CIRES and NOAA/ESRL) and developed robust in-house data quality assurance and validation methodologies. The average height of the thermal tropopause is between 15-17.5 km (125-85 hPa). Monthly average relative humidity around the tropopause shows an enhancement during the months of June through the beginning of October. Monthly average temperature profiles show the development of the subtropical subsidence inversion around 5-6 km (450-520 hPa) between the months of April through October. The subsidence inversion is strongest during the months of June and July and is accompanied by a sharp drop in relative humidity over a 100-300 m in the vertical. The monthly average ozone background concentration between the Planetary Boundary Layer (PBL) height and the subsidence inversion increases from 50 ppb in the winter to almost 80 ppb in the summer months. An enhancement of up to 50% in the average ozone in the mid-to-upper troposphere (above the subsidence inversion) is strongest during the summer months (June through September) and results in average concentrations between 80-100 ppb. In the upper troposphere (above 13 km/200 hPa) ozone concentrations are highest during the spring and summer months. This is coupled with a drop in the average height of the tropopause. HYSPLIT back-trajectory analysis shows the enhancement in mid-to-upper tropospheric ozone in the summer is due to persistent high pressure over the Middle East between the months of June through September. Evidence of Stratosphere-Troposphere Exchange

Tropospheric Ozone Pollution Transport Traced from the TOMS (Total Ozone Mapping Spectrometer) Instrument During the Nashville-1999 Campaign

NASA Technical Reports Server (NTRS)

Thompson, Anne M.; Frolov, A. D.; Hudson, R. D.; Witte, J. C.; Einaudi, Franco (Technical Monitor)

2000-01-01

Over the past several years, we have developed two new tropospheric ozone retrievals from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument that are of sufficient resolution to follow pollution episodes. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMS-direct method [("TDOT" = TOMS Direct Ozone in the Troposphere; Frolov et al., 2000] represents a new algorithm that uses TOMS radiances directly (i.e., not previously processed for TOMS ozone) to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution. These events tend to occur in certain meteorological regimes. For example, mid-latitude pollution usually occurs on the backside of subtropical fronts, as low pv, usually moist air intrudes to the extra-tropics. July 1999 was a month characterized by robust pollution in the eastern US, with high ozone, as detected by TOMS, originating over south central states and moving up the Atlantic seaboard. This corresponds to 50-80 DU in tropospheric ozone column depth. In most cases, further transport occurred to the North Atlantic, with ozone plumes traveling to western Europe in 4-5 days. Examples of high ozone and transit across boundaries within the US, as well as US->Europe, give a regional context for model results and field measurements taken in the SE US during the Nashville-1999 campaign period. Validation of the TDOT maps is made with ozonesondes taken during that time. TDOT maps also show ozone pollution from Asia traveling to the western US in July 1999.

LUNG INJURY AFTER OZONE EXPOSURE IS IRON-DEPENDENT

EPA Science Inventory

We tested the hypothesis that oxidative stress and biological effect after ozone (O3) exposure are dependent on changes in iron homeostasis. After O3 exposure, healthy volunteers demonstrated increased lavage concentrations of iron, transferrin, lactoferrin, and ferritin. In norm...

Ozone Layer Protection

MedlinePlus

... Offices Labs and Research Centers Contact Us Share Ozone Layer Protection The stratospheric ozone layer is Earth’s “ ... to ozone-depleting substances, and sun safety. Stratospheric Ozone Layer Basic Ozone Layer Science Health and Environmental ...

Convective Distribution of Tropospheric Ozone and Tracers in the Central American ITCZ Region: Evidence from Observations During TC4

NASA Technical Reports Server (NTRS)

Avery, Melody; Twohy, Cynthia; MCabe, David; Joiner, Joanna; Severance, Kurt; Atlas, Eliot; Blake, Donald; Bui, T. P.; Crounse, John; Dibb, Jack;

Meteorology-induced variations in the spatial behavior of summer ozone pollution in Central California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Ling; Harley, Robert A.; Brown, Nancy J.

Cluster analysis was applied to daily 8 h ozone maxima modeled for a summer season to characterize meteorology-induced variations in the spatial distribution of ozone. Principal component analysis is employed to form a reduced dimension set to describe and interpret ozone spatial patterns. The first three principal components (PCs) capture {approx}85% of total variance, with PC1 describing a general spatial trend, and PC2 and PC3 each describing a spatial contrast. Six clusters were identified for California's San Joaquin Valley (SJV) with two low, three moderate, and one high-ozone cluster. The moderate ozone clusters are distinguished by elevated ozone levels inmore » different parts of the valley: northern, western, and eastern, respectively. The SJV ozone clusters have stronger coupling with the San Francisco Bay area (SFB) than with the Sacramento Valley (SV). Variations in ozone spatial distributions induced by anthropogenic emission changes are small relative to the overall variations in ozone amomalies observed for the whole summer. Ozone regimes identified here are mostly determined by the direct and indirect meteorological effects. Existing measurement sites are sufficiently representative to capture ozone spatial patterns in the SFB and SV, but the western side of the SJV is under-sampled.« less

Revisiting Antarctic Ozone Depletion

NASA Astrophysics Data System (ADS)

Grooß, Jens-Uwe; Tritscher, Ines; Müller, Rolf

2015-04-01

Antarctic ozone depletion is known for almost three decades and it has been well settled that it is caused by chlorine catalysed ozone depletion inside the polar vortex. However, there are still some details, which need to be clarified. In particular, there is a current debate on the relative importance of liquid aerosol and crystalline NAT and ice particles for chlorine activation. Particles have a threefold impact on polar chlorine chemistry, temporary removal of HNO3 from the gas-phase (uptake), permanent removal of HNO3 from the atmosphere (denitrification), and chlorine activation through heterogeneous reactions. We have performed simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) employing a recently developed algorithm for saturation-dependent NAT nucleation for the Antarctic winters 2011 and 2012. The simulation results are compared with different satellite observations. With the help of these simulations, we investigate the role of the different processes responsible for chlorine activation and ozone depletion. Especially the sensitivity with respect to the particle type has been investigated. If temperatures are artificially forced to only allow cold binary liquid aerosol, the simulation still shows significant chlorine activation and ozone depletion. The results of the 3-D Chemical Transport Model CLaMS simulations differ from purely Lagrangian longtime trajectory box model simulations which indicates the importance of mixing processes.

Treatment of a simulated textile wastewater containing the Reactive Orange 16 azo dye by a combination of ozonation and moving-bed biofilm reactor: evaluating the performance, toxicity, and oxidation by-products.

PubMed

Castro, Francine D; Bassin, João Paulo; Dezotti, Márcia

2017-03-01

In this study, an aqueous solution containing the azo dye Reactive Orange 16 (RO16) was subjected to two sequential treatment processes, namely: ozonation and biological treatment in a moving-bed biofilm reactor (MBBR). The most appropriate ozonation pretreatment conditions for the biological process and the toxicity of the by-products resulting from RO16 ozone oxidation were evaluated. The results showed that more than 97 % of color removal from the dye solutions with RO16 concentrations ranging from 25 to 100 mg/L was observed in 5 min of ozone exposure. However, the maximum total organic carbon removal achieved by ozonation was only 48 %, indicating partial mineralization of the dye. Eleven intermediate organic compounds resulting from ozone treatment of RO16 solution were identified by LC/MS analyses at different contact times. The toxicity of the dye-containing solution decreased after 2 min of ozonation, but increased at longer contact times. The results further demonstrated that the ozonolysis products did not affect the performance of the subsequent MBBR, which achieved an average chemical oxygen demand (COD) and ammonium removal of 93 ± 1 and 97 ± 2 %, respectively. A second MBBR system fed with non-ozonated dye-containing wastewater was run in parallel for comparison purposes. This reactor also showed an appreciable COD (90 ± 1 %) and ammonium removal (97 ± 2 %), but was not effective in removing color, which remained practically invariable over the system. The use of short ozonation times (5 min) and a compact MBBR has shown to be effective for the treatment of the simulated textile wastewater containing the RO16 azo dye.

Impact of chemical plant start-up emissions on ambient ozone concentration

NASA Astrophysics Data System (ADS)

Ge, Sijie; Wang, Sujing; Xu, Qiang; Ho, Thomas

2017-09-01

Flare emissions, especially start-up flare emissions, during chemical plant operations generate large amounts of ozone precursors that may cause highly localized and transient ground-level ozone increment. Such an adverse ozone impact could be aggravated by the synergies of multiple plant start-ups in an industrial zone. In this paper, a systematic study on ozone increment superposition due to chemical plant start-up emissions has been performed. It employs dynamic flaring profiles of two olefin plants' start-ups to investigate the superposition of the regional 1-hr ozone increment. It also summaries the superposition trend by manipulating the starting time (00:00-10:00) of plant start-up operations and the plant distance (4-32 km). The study indicates that the ozone increment induced by simultaneous start-up emissions from multiple chemical plants generally does not follow the linear superposition of the ozone increment induced by individual plant start-ups. Meanwhile, the trend of such nonlinear superposition related to the temporal (starting time and operating hours of plant start-ups) and spatial (plant distance) factors is also disclosed. This paper couples dynamic simulations of chemical plant start-up operations with air-quality modeling and statistical methods to examine the regional ozone impact. It could be helpful for technical decision support for cost-effective air-quality and industrial flare emission controls.

Removal of endocrine-disrupting chemicals and conventional pollutants in a continuous-operating activated sludge process integrated with ozonation for excess sludge reduction.

PubMed

Nie, Yafeng; Qiang, Zhimin; Ben, Weiwei; Liu, Junxin

2014-06-01

Sludge ozonation is considered as a promising technology to achieve a complete reduction of excess sludge, but as yet its effects on the removal of endocrine-disrupting chemicals (EDCs) and conventional pollutants (i.e., COD, N and P) in the activated sludge process are still unclear. In this study, two lab-scale continuous-operating activated sludge treatment systems were established: one was operated in conjunction with ozonation for excess sludge reduction, and the other was operated under normal conditions as control. The results indicate that an ozone dose of 100 mg O₃ g(-1)SS led to a zero yield of excess sludge in the sludge-reduction system during a continuous-operating period of 45d. Although ozonation gave a relatively lower specific oxygen uptake rate of activated sludge, it had little effect on the system's removal performance of COD and nitrogen substances. As a plus, sludge ozonation contributed a little more removal of target EDCs (estrone, 17β-estrodiol, estriol, 17α-ethinylestradiol, bisphenol A, and 4-nonylphenol). However, the total phosphorus removal declined notably due to its accumulation in the sludge-reduction system, which necessitates phosphorus recovery for the activated sludge process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Photocatalytic ozonation under visible light for the remediation of water effluents and its integration with an electro-membrane bioreactor.

PubMed

Toledano Garcia, Diego; Ozer, Lütfiye Y; Parrino, Francesco; Ahmed, Menatalla; Brudecki, Grzegorz Przemyslaw; Hasan, Shadi W; Palmisano, Giovanni

2018-06-06

Photocatalysis and photocatalytic ozonation under visible light have been applied for the purification of a complex aqueous matrix such as the grey water of Masdar City (UAE), by using N-doped brookite-rutile catalysts. Preliminary runs on 4-nitrophenol (4-NP) solutions allowed to test the reaction system in the presence of a model pollutant and to afford the relevant kinetic parameters of the process. Subsequently, the remediation of grey water effluent has been evaluated in terms of the reduction of total organic carbon (TOC) and bacterial counts. The concentration of the most abundant inorganic ionic species in the effluent has been also monitored during reaction. Photocatalytic ozonation under visible light allowed to reduce the TOC content of the grey water by ca. 60% in the optimized experimental conditions and to reduce the total bacterial count by ca. 97%. The extent of TOC mineralization reached ca. 80% when the photocatalytic ozonation occurred downstream to a preliminary electro-membrane bioreactor (eMBR). Coupling the two processes enhanced the global efficiency. In fact, the eMBR treatment lowered the turbidity and the organic load of the effluent entering the photocatalytic ozonation treatment, which in turn enhanced the extent of purification and disinfection. Copyright © 2018 Elsevier Ltd. All rights reserved.

Occurrence and fate of amisulpride, sulpiride, and lamotrigine in municipal wastewater treatment plants with biological treatment and ozonation.

PubMed

Bollmann, Anna Franka; Seitz, Wolfram; Prasse, Carsten; Lucke, Thomas; Schulz, Wolfgang; Ternes, Thomas

2016-12-15

This study examines the transformation and removal of the atypical antipsychotics amisulpride and sulpiride and the anticonvulsant lamotrigine in municipal wastewater treatment plants (WWTPs). Amisulpride, sulpiride and lamotrigine were selected using a tailored non-target screening approach. In WWTPs, lamotrigine concentrations increased from 1.1 to 1.6μg/L while sulpiride and amisulpride exhibited similar concentrations, up to 1.1μg/L and 1.3μg/L, respectively. It was found that N2-glucuronide conjugates of lamotrigine were cleaved to form lamotrigine. Both lamotrigine and amisulpride were detected in groundwater with a concentration of 0.07μg/L. Sulpiride was identified but not quantified. This demonstrates that amisulpride, sulpiride and lamotrigine might be used as indicators for treated wastewater in raw waters used for drinking water production. Furthermore, it could be shown that all three pharmaceutical compounds are efficiently oxidized by ozonation, leading mainly to N-oxide oxidation products. No significant removal of the N-oxides of amisulpride, sulpiride and lamotrigine was observed in the bench-scale biodegradation experiments with activated sludge. This indicated their high biological persistence. Therefore, N-oxides might be appropriate as indicators for post-ozonation as a major technology for the advanced treatment of secondary effluent. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of the synergistic effects for p-nitrophenol mineralization by a combined process of ozonation and electrolysis using a boron-doped diamond anode.

PubMed

Qiu, Cuicui; Yuan, Shi; Li, Xiang; Wang, Huijiao; Bakheet, Belal; Komarneni, Sridhar; Wang, Yujue

2014-09-15

Electrolysis and ozonation are two commonly used technologies for treating wastewaters contaminated with nitrophenol pollutants. However, they are often handicapped by their slow kinetics and low yields of total organic carbon (TOC) mineralization. To improve TOC mineralization efficiency, we combined electrolysis using a boron-doped diamond (BDD) anode with ozonation (electrolysis-O3) to treat a p-nitrophenol (PNP) aqueous solution. Up to 91% TOC was removed after 60 min of the electrolysis-O3 process. In comparison, only 20 and 44% TOC was respectively removed by individual electrolysis and ozonation treatment conducted under similar reaction conditions. The result indicates that when electrolysis and ozonation are applied simultaneously, they have a significant synergy for PNP mineralization. This synergy can be mainly attributed to (i) the rapid degradation of PNP to carboxylic acids (e.g., oxalic acid and acetic acid) by O3, which would otherwise take a much longer time by electrolysis alone, and (ii) the effective mineralization of the ozone-refractory carboxylic acids to CO2 by OH generated from multiple sources in the electrolysis-O3 system. The result suggests that combining electrolysis with ozonation can provide a simple and effective way to mutually compensate the limitations of the two processes for degradation of phenolic pollutants. Copyright © 2014 Elsevier B.V. All rights reserved.

Uncertainties in models of tropospheric ozone based on Monte Carlo analysis: Tropospheric ozone burdens, atmospheric lifetimes and surface distributions

NASA Astrophysics Data System (ADS)

Derwent, Richard G.; Parrish, David D.; Galbally, Ian E.; Stevenson, David S.; Doherty, Ruth M.; Naik, Vaishali; Young, Paul J.

2018-05-01

Recognising that global tropospheric ozone models have many uncertain input parameters, an attempt has been made to employ Monte Carlo sampling to quantify the uncertainties in model output that arise from global tropospheric ozone precursor emissions and from ozone production and destruction in a global Lagrangian chemistry-transport model. Ninety eight quasi-randomly Monte Carlo sampled model runs were completed and the uncertainties were quantified in tropospheric burdens and lifetimes of ozone, carbon monoxide and methane, together with the surface distribution and seasonal cycle in ozone. The results have shown a satisfactory degree of convergence and provide a first estimate of the likely uncertainties in tropospheric ozone model outputs. There are likely to be diminishing returns in carrying out many more Monte Carlo runs in order to refine further these outputs. Uncertainties due to model formulation were separately addressed using the results from 14 Atmospheric Chemistry Coupled Climate Model Intercomparison Project (ACCMIP) chemistry-climate models. The 95% confidence ranges surrounding the ACCMIP model burdens and lifetimes for ozone, carbon monoxide and methane were somewhat smaller than for the Monte Carlo estimates. This reflected the situation where the ACCMIP models used harmonised emissions data and differed only in their meteorological data and model formulations whereas a conscious effort was made to describe the uncertainties in the ozone precursor emissions and in the kinetic and photochemical data in the Monte Carlo runs. Attention was focussed on the model predictions of the ozone seasonal cycles at three marine boundary layer stations: Mace Head, Ireland, Trinidad Head, California and Cape Grim, Tasmania. Despite comprehensively addressing the uncertainties due to global emissions and ozone sources and sinks, none of the Monte Carlo runs were able to generate seasonal cycles that matched the observations at all three MBL stations. Although

Two-dimensional model studies of the effect of supersonic aircraft operations on the stratospheric ozone content

NASA Technical Reports Server (NTRS)

Whitten, R. C.; Borucki, W. J.; Poppoff, I. G.; Latt, L.; Widhopf, G. F.; Capone, L. A.; Reigel, C. A.

1981-01-01

For a fleet of 250 aircraft, the change in the ozone column is predicted to be very close to zero; in fact, the ozone overburden may actually increase as a result of show that above 25 to 30 km the ozone abundance decreases via catalytic destruction, but at lower heights it increases, mainly as a result of coupling with odd hydrogen species. Water vapor released in the engine exhaust is predicted to cause ozone decreases; for the hypothetical engines used in the study, the total column ozone changes due to water vapor emission largely offset the predicted ozone increases due to NOx emission. The actual effect of water vapor may be less than calculated because present models do not include thermal feedback. Feedback refers to the cooling effect of additional water vapor that would tend to slow the NOx reactions which destroy ozone.

IVF, same-sex couples and the value of biological ties.

PubMed

Di Nucci, Ezio

2016-12-01

Ought parents, in general, to value being biologically tied to their children? Is it important, in particular, that both parents be biologically tied to their children? I will address these fundamental questions by looking at a fairly new practice within IVF treatments, so-called IVF-with-ROPA (Reception of Oocytes from Partner), which allows lesbian couples to 'share motherhood', with one partner providing the eggs while the other becomes pregnant. I believe that IVF-with-ROPA is, just like other IVF treatments, morally permissible, but here I argue that the increased biological ties which IVF-with-ROPA allows for do not have any particular value beside the satisfaction of a legitimate wish, because there is no intrinsic value in a biological tie between parents and children; further, I argue that equality within parental projects cannot be achieved by redistributing biological ties. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Ozone Layer Observations

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Tropospheric Enhancement of Ozone over the UAE

NASA Astrophysics Data System (ADS)

Abbasi, Naveed Ali; Majeed, Tariq; Iqbal, Mazhar; Kaminski, Jacek; Struzewska, Joanna; Durka, Pawel; Tarasick, David; Davies, Jonathan

2015-04-01

We use the Global Environmental Multiscale - Air Quality (GEM-AQ) model to interpret the vertical profiles of ozone acquired with ozone sounding experiments at the meteorological site located at the Abu Dhabi airport. The purpose of this study is to gain insight into the chemical and dynamical structures in the atmosphere of this unique subtropical location (latitude 24.45N; longitude 54.22E). Ozone observations for years 2012 - 2013 reveal elevated ozone abundances in the range from 70 ppbv to 120 ppbv near 500-400 hPa during summer. The ozone abundances in other seasons are much lower than these values. The preliminary results indicate that summertime enhancement in ozone is associated with the Arabian anticyclones centered over the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water. The model also shows considerable seasonal variation in the tropospheric ozone which is transported from the stratosphere by dynamical processes. The domestic production of ozone in the middle troposphere is estimated and compared GEM-AQ model. It is estimated that about 40-50% of ozone in the UAE is transported from the neighbouring petrochemical industries in the Gulf region. We will present ozone sounding data and GEM-AQ results including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

Evaluation of the persistence of transformation products from ozonation of trace organic compounds - a critical review.

PubMed

Hübner, Uwe; von Gunten, Urs; Jekel, Martin

2015-01-01

Ozonation is an efficient treatment system to reduce the concentration of trace organic compounds (TrOCs) from technical aquatic systems such as drinking water, wastewater and industrial water, etc. Although it is well established that ozonation generally improves the removal of organic matter in biological post-treatment, little is known about the biodegradability of individual transformation products resulting from ozonation of TrOCs. This publication provides a qualified assessment of the persistence of ozone-induced transformation products based on a review of published product studies and an evaluation of the biodegradability of transformation products with the biodegradability probability program (BIOWIN) and the University of Minnesota Pathway Prediction System (UM-PPS). The oxidation of TrOCs containing the four major ozone-reactive sites (olefins, amines, aromatics and sulfur-containing compounds) follows well described reaction pathways leading to characteristic transformation products. Assessment of biodegradability revealed a high sensitivity to the formed products and hence the ozone-reactive site present in the target compound. Based on BIOWIN, efficient removal can be expected for products from cleavage of olefin groups and aromatic rings. In contrast, estimations and literature indicate that hydroxylamines and N-oxides, the major products from ozonation of secondary and tertiary amines are not necessarily better removed in biological post-treatment. According to UM-PPS, degradation of these products might even occur via reformation of the corresponding amine. Some product studies with sulfide-containing TrOCs showed a stoichiometric formation of sulfoxides from oxygen transfer reactions. However, conclusions on the fate of transformation products in biological post-treatment cannot be drawn based on BIOWIN and UM-PPS.

Surface ozone variability at Kislovodsk Observatory

NASA Technical Reports Server (NTRS)

Elansky, Nikolay F.; Makarov, Oleg V.; Senik, Irina A.

1994-01-01

The results of the surface ozone observations at the Observatory 'Kislovodsk', situated in the North Caucasus at the altitude 2070 m a.s.l., are given. The observatory is in the background conditions and the variations of the surface ozone are determined by the natural dynamic and photochemical processes. The mean value of the concentration and its seasonal variations are very near to those obtained at the high-mountain stations in Alps. The daily variations have the features, which remain stable during all warm period of the year (April-October). These features, including the minimum of the surface ozone at noon, are formed by the mountain-valley circulation. The significant variations of the surface ozone are connected with the unstationary lee waves.

Solar or UVA-Visible Photocatalytic Ozonation of Water Contaminants.

PubMed

Beltrán, Fernando J; Rey, Ana

2017-07-14

An incipient advanced oxidation process, solar photocatalytic ozonation (SPO), is reviewed in this paper with the aim of clarifying the importance of this process as a more sustainable water technology to remove priority or emerging contaminants from water. The synergism between ozonation and photocatalytic oxidation is well known to increase the oxidation rate of water contaminants, but this has mainly been studied in photocatalytic ozonation systems with lamps of different radiation wavelength, especially of ultraviolet nature (UVC, UVB, UVA). Nowadays, process sustainability is critical in environmental technologies including water treatment and reuse; the application of SPO systems falls into this category, and contributes to saving energy and water. In this review, we summarized works published on photocatalytic ozonation where the radiation source is the Sun or simulated solar light, specifically, lamps emitting radiation to cover the UVA and visible light spectra. The main aspects of the review include photoreactors used and radiation sources applied, synthesis and characterization of catalysts applied, influence of main process variables (ozone, catalyst, and pollutant concentrations, light intensity), type of water, biodegradability and ecotoxicity, mechanism and kinetics, and finally catalyst activity and stability.

Understanding Ozone: Exploring the Good and Bad Facets of a Famous Gas.

ERIC Educational Resources Information Center

Hanif, Muhammad

1995-01-01

Presents activities that help students distinguish between the beneficial layer of stratospheric ozone and the dangerous ground-level or tropospheric ozone, understand the chemical processes of ozone breakdown in the stratosphere, find the sources of ground-level ozone, and explore the differences in the patterns of ozone concentration over the…

Removal of geosmin and 2-methylisoborneol by biological filtration.

PubMed

Elhadi, S L N; Huck, P M; Slawson, R M

2004-01-01

The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to

Antarctic ozone loss in 1989-2010: evidence for ozone recovery?

NASA Astrophysics Data System (ADS)

Kuttippurath, J.; Lefèvre, F.; Pommereau, J.-P.; Roscoe, H. K.; Goutail, F.; Pazmiño, A.; Shanklin, J. D.

2012-04-01

We present a detailed estimation of chemical ozone loss in the Antarctic polar vortex from 1989 to 2010. The analyses include ozone loss estimates for 12 Antarctic ground-based (GB) stations. All GB observations show minimum ozone in the late September-early October period. Among the stations, the lowest minimum ozone values are observed at South Pole and the highest at Dumont d'Urville. The ozone loss starts by mid-June at the vortex edge and then progresses towards the vortex core with time. The loss intensifies in August-September, peaks by the end of September-early October, and recovers thereafter. The average ozone loss in the Antarctic is revealed to be about 33-50% in 1989-1992 in agreement with the increase in halogens during this period, and then stayed at around 48% due to saturation of the loss. The ozone loss in the warmer winters (e.g. 2002, and 2004) is lower (37-46%) and in the colder winters (e.g. 2003, and 2006) is higher (52-55%). Because of small inter-annual variability, the correlation between ozone loss and the volume of polar stratospheric clouds yields ~0.51. The GB ozone and ozone loss values are in good agreement with those found from the space-based observations of the Total Ozone Mapping Spectrometer/Ozone Monitoring Instrument (TOMS/OMI), the Global Ozone Monitoring Experiment (GOME), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and the Aura Microwave Limb Sounder (MLS), where the differences are within ±5% and are mostly within the error bars of the measurements. The piece-wise linear trends computed from the September-November vortex average GB and TOMS/OMI ozone show about -4 to -5.6 DU (Dobson Unit) yr-1 in 1989-1996 and about +1 DU yr-1 in 1997-2010. The trend during the former period is significant at 95% confidence intervals, but the trend in 1997-2010 is significant only at 85% confidence intervals. Our analyses suggest a period of about 9-10 yr to get the first detectable ozone

The Version 8.6 SBUV Ozone Data Record: An Overview

NASA Technical Reports Server (NTRS)

McPeters, Richard D.; Bhartia, P. K.; Haffner, D.; Labow, Gordon J.; Flynn, Larry

2013-01-01

Under a NASA program to produce long-term data records from instruments on multiple satellites, data from a series of nine Solar Backscatter Ultraviolet (SBUV and SBUV2) instruments have been re-processed to create a coherent ozone time series. Data from the BUV instrument on Nimbus 4, SBUV on Nimbus 7, and SBUV2 instruments on NOAA 9, 11, 14, 16, 17, 18, and 19 covering the period 1970-1972 and 1979-2011 were used to create a long-term data set. The goal is an ozone Earth Science Data Record - a consistent, calibrated ozone time series that can be used for trend analyses and other studies. In order to create this ozone data set, the radiances were adjusted and used to re-process the entire data records for each of the nine instruments. Inter-instrument comparisons during periods of overlap as well as comparisons with data from other satellite and ground-based instruments were used to evaluate the consistency of the record and make calibration adjustments as needed. Additional improvements in this version 8.6 processing included the use of the Brion, Daumont, and Malicet ozone cross sections, and a cloud-height climatology derived from Aura OMI measurements. Validation of the re-processed ozone shows that total column ozone is consistent with the Brewer Dobson network to within about 1 for the new time series. Comparisons with MLS, SAGE, sondes, and lidar show that ozone at individual levels in the stratosphere is generally consistent to within 5 percent.

Ecological issues related to ozone: agricultural issues.

PubMed

Fuhrer, Jürg; Booker, Fitzgerald

2003-06-01

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

Boulder Ozone Sonde Data Analyses for Multiple Tropopause Origins

NASA Astrophysics Data System (ADS)

Petropavlovskikh, I. V.; Manney, G. L.; Johnson, B.; Minschwaner, K.; Torres, L.; Lawrence, Z. D.

2014-12-01

Boulder ozone profile measurements tend to feature structures with multiple layers in the troposphere, so called laminae. These have been shown to be related to several phenomena, including stratospheric air intrusions that are transported to the location of measurements and local gravity wave perturbations (Boulder is located near the Rocky Mountain range where gravity waves are prevalent). In addition, observations indicate that air from the tropical tropopause layer can be transported into regions with multiple tropopauses over the middle latitudes in the vicinity of the subtropical jets. We use GMAO's GEOS-5 data assimilation system products, including Modern-Era Retrospective analysis for Research and Applications (MERRA), interpolated to Boulder, Colorado, USA (40N, 105W) to assess incidence of upper tropospheric jets that influence UTLS ozone distribution. The proximity of the subtropical jet to Boulder results in frequent observations of multiple tropopauses. We analyze ozonesonde data launched in June-July 2014 to determine the origins of laminae observed in the upper troposphere/lower stratosphere (UTLS). Our tools include back trajectory analysis coupled with 4D satellite ozone profile data, including those from NASA's Aura Microwave Limb Sounder instrument. Filaments causing laminae in ozone profiles observed at Boulder will be tracked to origins in either stratospheric or tropospheric intrusions using reverse domain-filling (RDF) trajectory methods. Detailed studies of several ozone profiles collected over Boulder in June/July 2014 will help determine techniques for future analysis of a larger dataset that goes back to 1978. Ozone variability in the UTLS over Boulder is of importance for studies of local climatological ozone conditions, their causes/attribution, and with regard to EPA ozone regulations at the mountain sites across the USA.

Impact of East Asian Summer Monsoon on Surface Ozone Pattern in China

NASA Astrophysics Data System (ADS)

Li, Shu; Wang, Tijian; Huang, Xing; Pu, Xi; Li, Mengmeng; Chen, Pulong; Yang, Xiu-Qun; Wang, Minghuai

2018-01-01

Tropospheric ozone plays a key role in regional and global atmospheric and climate systems. In East Asia, ozone can be affected both in concentration level and spatial pattern by typical monsoon climate. This paper uses three different indices to identify the strength of East Asian summer monsoon (EASM) and explores the possible impact of EASM intensity on the ozone pattern through synthetic and process analysis. The difference in ozone between three strong and three weak monsoon years was analyzed using the simulations from regional climate model RegCM4-Chem. It was found that EASM intensity can significantly influence the spatial distribution of ozone in the lower troposphere. When EASM is strong, ozone in the eastern part of China (28°N - 42° N) is reduced, but the inverse is detected in the north and south. The surface ozone difference ranges from -7 to 7 ppbv during the 3 months (June to August) of the EASM, with the most obvious difference in August. Difference of the 3 months' average ozone ranges from -3.5 to 4 ppbv. Process analysis shows that the uppermost factor controlling ozone level during summer monsoon seasons is the chemistry process. Interannual variability of EASM can impact the spatial distribution of ozone through wind in the lower troposphere, cloud cover, and downward shortwave radiation, which affect the transport and chemical formation of ozone. The phenomenon should be addressed when considering the interaction between ozone and the climate in East Asia region.

Comparison of coagulation, ozone and ferrate treatment processes for color, COD and toxicity removal from complex textile wastewater.

PubMed

Malik, Sameena N; Ghosh, Prakash C; Vaidya, Atul N; Waindeskar, Vishal; Das, Sera; Mudliar, Sandeep N

2017-09-01

In this study, the comparative performance of coagulation, ozone, coagulation + ozone + coagulation and potassium ferrate processes to remove chemical oxygen demand (COD), color, and toxicity from a highly polluted textile wastewater were evaluated. Experimental results showed that ferrate alone had no effect on COD, color and toxicity removal. Whereas, in combination with FeSO 4 , it has shown the highest removal efficiency of 96.5%, 83% and 75% for respective parameters at the optimal dose of 40 mgL -1 + 3 ml FeSO 4 (1 M) in comparison with other processes. A seed germination test using seeds of Spinach (Spinacia oleracea) also indicated that ferrate was more effective in removing toxicity from contaminated textile wastewater. Potassium ferrate also produces less sludge with maximum contaminant removal, thereby making the process more economically feasible. Fourier transform infrared spectroscopy (FTIR) analysis also shows the cleavage of the chromophore group and degradation of textile wastewater during chemical and oxidation treatment processes.

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

NASA Astrophysics Data System (ADS)

Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

2015-08-01

Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

Hydromechanical coupling in geologic processes

USGS Publications Warehouse

Neuzil, C.E.

2003-01-01

Earth's porous crust and the fluids within it are intimately linked through their mechanical effects on each other. This paper presents an overview of such "hydromechanical" coupling and examines current understanding of its role in geologic processes. An outline of the theory of hydromechanics and rheological models for geologic deformation is included to place various analytical approaches in proper context and to provide an introduction to this broad topic for nonspecialists. Effects of hydromechanical coupling are ubiquitous in geology, and can be local and short-lived or regional and very long-lived. Phenomena such as deposition and erosion, tectonism, seismicity, earth tides, and barometric loading produce strains that tend to alter fluid pressure. Resulting pressure perturbations can be dramatic, and many so-called "anomalous" pressures appear to have been created in this manner. The effects of fluid pressure on crustal mechanics are also profound. Geologic media deform and fail largely in response to effective stress, or total stress minus fluid pressure. As a result, fluid pressures control compaction, decompaction, and other types of deformation, as well as jointing, shear failure, and shear slippage, including events that generate earthquakes. By controlling deformation and failure, fluid pressures also regulate states of stress in the upper crust. Advances in the last 80 years, including theories of consolidation, transient groundwater flow, and poroelasticity, have been synthesized into a reasonably complete conceptual framework for understanding and describing hydromechanical coupling. Full coupling in two or three dimensions is described using force balance equations for deformation coupled with a mass conservation equation for fluid flow. Fully coupled analyses allow hypothesis testing and conceptual model development. However, rigorous application of full coupling is often difficult because (1) the rheological behavior of geologic media is complex

Can Assimilation of Satellite Ozone Data Contribute to the Understanding of the Lower Stratospheric Ozone?

NASA Technical Reports Server (NTRS)

Stajner, I.; Wargan, K.; Pawson, S.; Hayashi, H.; Chang, L.-P.; Rood, R.

2004-01-01

We study the quality of lower stratospheric ozone fields from a three- dimensional global ozone assimilation system. Ozone in this region is important for the forcing of climate, but its global distribution is not fully known because of its large temporal and vertical variability. Modeled fields often have biases due to the inaccurate representation of transport processes in this region with strong gradients. Accurate ozonesonde or satellite occultation measurements have very limited coverage. Nadir measurements, such as those from the Solar Backscatter Ultraviolet/2 (SBUV/2) instrument that provide wide latitudinal coverage, lack the vertical resolution needed to represent sharp vertical features. Limb measurements, such as those from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), provide a finer vertical resolution. We show that assimilation of MIPAS data in addition to SBUV/2 data leads to better estimates of ozone in comparison with independent high quality satellite, aircraft, and ozone sonde measurements. Other modifications to the statistical analysis that have an impact on the lower stratospheric ozone will be mentioned: error covariance modeling and data selection. Direct and indirect impacts of transport and chemistry models will be discussed. Implications for multi-year analyses and short-tern prediction will be addressed.

Flavor and appearance of whole shell eggs made safe with ozone pasteurization

PubMed Central

Maxkwee, Esther N; Perry, Jennifer J; Lee, Ken

2014-01-01

Raw eggs are a potential health hazard and a new federally approved process uses ozone to maintain freshness while ensuring safety. The impact of an ozone process on the flavor, color, and shell integrity of eggs must be known for market acceptance. The visual perception and consumer acceptance of full commercial scale ozone-pasteurized eggs are reported, using a degree of liking test and a Just-About-Right analysis. Instrumental analysis of albumen turbidity, yolk color, and Haugh Units correlate with human perception. Visual tests reveal that ozone-pasteurized eggs were equivalent to thermally pasteurized eggs in attributes such as appearance, spread, and cloudiness. They were equivalent to untreated eggs in yolk height, yellowness, and appeal. There were no differences in taste among all egg treatments for measures of aroma, flavor, texture and overall liking. Ozone-pasteurized eggs have the same appeal as raw eggs, and can be cooked without flavor loss. This promising new ozone process maintains good sensory quality relative to thermal processing. PMID:25473516

Laboratory studies of chemical and photochemical processes relevant to stratospheric ozone

NASA Technical Reports Server (NTRS)

Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

1994-01-01

The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(sub x) and NO(sub x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO2 radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. In this annual report, we focus on our recent accomplishments in the quantitative spectroscopy of the HO2 radical. This report details the measurements of the broadening coefficients for the v(sub 2) vibrational band. Further measurements of the vapor pressures of nitric acid hydrates relevant to the polar stratospheric cloud formation indicate the importance of metastable crystalline phases of H2SO4, HNO3, and H2O. Large particles produced from these metastable phases may provide a removal mechanism for HNO3 in the polar stratosphere.

Effects of Greenhouse Gas Increase and Stratospheric Ozone Depletion on Stratospheric Mean Age of Air in 1960-2010

NASA Astrophysics Data System (ADS)

Li, F.; Newman, P. A.; Pawson, S.; Perlwitz, J.

2017-12-01

The strength of the stratospheric Brewer-Dobson circulation (BDC) in a changing climate has been extensively studied, but the relative importance of greenhouse gas (GHG) increases and stratospheric ozone depletion in driving the BDC changes remains uncertain. This study separates the impacts of GHG and stratospheric ozone forcings on stratospheric mean age of air in the 1960-2010 period using the Goddard Earth Observing System Model (GEOS) Chemistry-Climate Model (CCM). The experiment compares a set of controlled simulations using a coupled atmosphere-ocean version of the GEOS CCM, in which either GHGs, or stratospheric ozone, or both factors evolve over time. The model results show that GHGs and stratospheric ozone have about equal contributions to the simulated mean age decrease. It is also found that GHG increases account for about two thirds of the enhanced strength of the lower stratospheric residual circulation. The results show that ozone depletion causes an increase in the mean age of air in the Antarctic summer lower stratosphere through two processes: 1) a seasonal delay in the Antarctic polar vortex breakup, that inhibits young mid-latitude air from mixing with the older air inside the vortex; and 2) enhanced Antarctic downwelling, that brings older air from middle and upper stratosphere into the lower stratosphere.

Ozone decomposition

PubMed Central

Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho

2014-01-01

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. PMID:26109880

From globally coupled maps to complex-systems biology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneko, Kunihiko, E-mail: kaneko@complex.c.u-tokyo.ac.jp

Studies of globally coupled maps, introduced as a network of chaotic dynamics, are briefly reviewed with an emphasis on novel concepts therein, which are universal in high-dimensional dynamical systems. They include clustering of synchronized oscillations, hierarchical clustering, chimera of synchronization and desynchronization, partition complexity, prevalence of Milnor attractors, chaotic itinerancy, and collective chaos. The degrees of freedom necessary for high dimensionality are proposed to equal the number in which the combinatorial exceeds the exponential. Future analysis of high-dimensional dynamical systems with regard to complex-systems biology is briefly discussed.

Magnetosphere-ionosphere coupling: processes and rates

NASA Astrophysics Data System (ADS)

Lotko, W.

Magnetosphere-ionosphere coupling describes the interaction between the collisionless plasma of the magnetosphere and the ionized and neutral collisional gases of the ionosphere and thermosphere. This coupling introduces feedback and scale interactivity in the form of a time-variable mass flux, electron energy flux and Poynting flux flowing between the two regions. Although delineation of an MI coupling region is somewhat ambiguous, at mid and high latitudes it may be considered as the region of the topside ionosphere and low-altitude magnetosphere where electromagnetic energy is converted to plasma beams and heat via collisionless dissipation processes. Above this region the magnetically guided transmission of electromagnetic power from distant magnetospheric dynamos encounters only weak attenuation. The ionospheric region below it is dominated by ionization processes and collisional cross-field transport and current closure. This tutorial will use observations, models and theory to characterize three major issues in MI coupling: (1) the production of plasma beams and heat in the coupling region; (2) the acceleration of ions leading to massive outflows; and (3) the length and time scale dependence of electromagnetic energy deposition at low altitude. Our success in identifying many of the key processes is offset by a lack of quantitative understanding of the factors controlling the rates of energy deposition and of the production of particle energy and mass fluxes.

Long-term Ozone Changes and Associated Climate Impacts in CMIP5 Simulations

NASA Technical Reports Server (NTRS)

Eyring, V.; Arblaster, J. M.; Cionni, I.; Sedlacek, J.; Perlwitz, J.; Young, P. J.; Bekki, S.; Bergmann, D.; Cameron-Smith, P.; Collins, W. J.;

Treatment of oil sands process-affected water (OSPW) using ozonation combined with integrated fixed-film activated sludge (IFAS).

PubMed

Huang, Chunkai; Shi, Yijing; Gamal El-Din, Mohamed; Liu, Yang

2015-11-15

Two integrated fixed-film activated sludge (IFAS) reactors were operated continuously to treat raw (untreated) and ozonated (30 mg/L) oil sands process-affected water (OSPW). After 11 months, 12.1% of the acid extractable fraction (AEF) and 43.1% of the parent naphthenic acids (NAs) were removed in the raw OSPW IFAS, while 42.0% AEF and 80.2% of parent NAs were removed in the ozonated OSPW IFAS. UPLC/HRMS analysis showed that NA biodegradation significantly decreased as the NA cyclization number increased. Confocal laser scanning microscopy (CLSM) results showed that the biofilm in the ozonated OSPW IFAS was significantly thicker (94 ± 1.6 μm) than the biofilm in the raw OSPW IFAS (72 ± 2.8 μm) after 283 days of cultivation. The quantitative polymerase chain reaction (q-PCR) revealed that the abundance proportions of both nitrifier genes (AomA, NSR and Nitro) and denitrifier genes (narG, nirS, nirK and nosZ) within total bacteria were significantly higher in biofilms than in flocs in the raw OSPW IFAS system, but a different trend was observed in the ozonated OSPW IFAS system. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the Identification of Ozone Recovery