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Safeguarding the Ozone Layer and the Global Climate System: Issues related to hydrofluorocarbons and perfluorocarbons

Description: This Special Report on Safeguarding the Ozone and the Global Climate System has been developed in response to invitations from Parties to the UNFCCC and the Montreal Protocol. It provides information relevant to decision-making in regard to safeguarding the ozone layer and the global climate system: two global environmental issues involving complex scientific and technical considerations.
Date: 2005
Creator: Intergovernmental Panel on Climate Change
Partner: UNT Libraries
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Ozone

Description: The term "ozone depletion" means more than just the natural destruction of ozone, it means that ozone loss is exceeding ozone creation.
Date: 2002
Creator: NASA Earth Observatory
Partner: UNT Libraries
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Ozone

Description: The amount and distribution of ozone molecules in the stratosphere varies greatly over the globe. Ozone molecules are transported around the stratosphere much as water clouds are transported in the troposphere. Therefore, scientists observing ozone fluctuations over just one spot could not know whether a change in local ozone levels meant an alteration in global ozone levels, or simply a fluctuation in the concentration over that particular spot. Satellites have given scientists the ability to overcome this problem because they provide a picture of what is happening daily over the entire Earth.
Date: 2002
Creator: NASA Earth Observatory
Partner: UNT Libraries
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Ozone

Description: In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. There is so much oxygen in our atmosphere, that these high-energy ultraviolet rays are completely absorbed in the stratosphere.
Date: 2002
Creator: NASA Earth Observatory
Partner: UNT Libraries

Automated Low-cost Instrument for Measuring Total Column Ozone

Description: Networks of ground-based and satellite borne instruments to measure ultraviolet (UV) sunlight and total column ozone have greatly contributed to an understanding of increased amounts of UV reaching the surface of the Earth caused by stratospheric ozone depletion. Increased UV radiation has important potential effects on human health, and agricultural and ecological systems. Observations from these networks make it possible to monitor total ozone decreases and to predict ozone recovery trends due to global efforts to curb the use of products releasing chemicals harmful to the ozone layer. Thus, continued and expanded global monitoring of ozone and UV is needed. However, existing automatic stratospheric ozone monitors are complex and expensive instruments. The main objective of this research was the development of a low-cost fully automated total column ozone monitoring instrument which, because of its affordability, will increase the number of instruments available for ground-based observations. The new instrument is based on a high-resolution fiber optic spectrometer, coupled with fiber optics that are precisely aimed by a pan and tilt positioning mechanism and with controlling programs written in commonly available software platforms which run on a personal computer. This project makes use of novel low-cost fiber optic spectrometer technology. A cost advantage is gained over available units by placing one end of the fiber outdoors to collect sunlight and convey it indoors, thereby allowing the spectrometer and computer to be placed in a controlled environment. This reduces the cost of weatherproofing and thermal compensation. Cost savings also result from a simplified sun targeting system, because only a small pan and tilt device is required to aim the lightweight fiber optic ends. Precision sun-targeting algorithms, optical filter selection, and software to derive ozone from spectral measurements by the spectrometer are a major contribution of this project. This system is a flexible platform …
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: May 2006
Creator: Nebgen, Gilbert Bernard
Partner: UNT Libraries
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Reconstruction and Prediction of Variations of Total Ozone and Associated Variations of UV-B Solar Radiation for Subarctic Regions Based of Dendrochronologic Data

Description: Variations of dendrochronologic parameters, especially annual ring density, significantly reflect the physiological tree response to systematic variations of solar UV-B radiation, taking place on monthly and longer timescales during growing season. Such variations of UV-B radiation are totally governed by variations of total ozone (TO). Thus, in any dendrochronologic signal, especially for coniferous trees, there is also a recorded response to TO variations, characterizing variations of UV-B radiation. Because a monitoring of global TO distribution is regularly performed since 1979 using TOMS satellite instrumentation, there appears a possibility to reconstruct TO behavior in the past practically at any point of dendrochronologic monitoring network. The reconstruction is performed by the method of linear regression, based on significant correlation of annual ring density of coniferous trees and TO for coordinates of denrochronologic signal. The present report considers the Subarctic latitudes, which are characterized by considerable TO variations in the second half of twentieth century.
Date: March 18, 2005
Creator: Zuev, V. V. & Bondarenko, S. L.
Partner: UNT Libraries Government Documents Department
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Photodissociation of ozone at 276nm by photofragment imaging and high resolution photofragment translational spectroscopy

Description: The photodissociation of ozone at 276 nm is investigated using both state resolved ion imaging and high-resolution photofragment translational spectroscopy. Ion images from both [3+1] and [2+1] resonance enhanced multiphoton ionization of the O({sup 1}D) photofragment are reported. All images show strong evidence of O({sup 1}D) orbital alignment. Photofragment translation spectroscopy time-of-flight spectra are reported for the O{sub 2} ({sup 1}{Delta}{sub g}) photofragment. Total kinetic energy release distributions determined form these spectra are generally consistent with those distributions determined from imaging data. Observed angular distributions are reported for both detection methods, pointing to some unresolved questions for ozone dissociation in this wavelength region.
Date: November 1, 1996
Creator: Blunt, D. A. & Suits, A. G.
Partner: UNT Libraries Government Documents Department
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Comparison of CCM3 simulations using two climatological ozone data sets

Description: A comparison of two six year simulations with the CCM3 using different monthly mean, zonally symmetric ozone climatologies is presented. Each run was identical except for the ozone specification. The climatological SSTs supplied with CCM3 were cycled for the extent of the simulation. The ozone data sets were used were the data distributed with the CCM3 code and that compiled at SUNY Albany. The SUNYA data set reflects contemporary ozone measurements extensively using remote sensing data. The CCM3 data were produced from measurements prior to 1974. A brief comparison of the two ozone climatologies is presented. The monthly mean difference fields were computed for the six years of the simulations. A t-test was applied to the monthly mean difference to judge if the changes between the integrations were significant. The significant changes in temperature were for the most part confined to the levels above 200 hPa. In the zonal mean the patterns of differences were largely consistent with regions of the ozone variations, deeper tropospheric penetration of temperature difference occurred in October near the South Pole in the region of the `ozone hole`. The significant temperature changes at the lowest model level (approximately 992 hPa) were confined to very small areas. The 200 hPa zonal wind differences demonstrated that the stationary wave structure was evidently altered by the ozone difference. Although the ozone specifications were zonally symmetric, the zonal wind differences were zonally asymmetric at 200 hPa.
Date: February 1, 1997
Creator: Boyle, J.S.
Partner: UNT Libraries Government Documents Department
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SAGE II/Umkehr ozone comparisons and aerosols effects: An empirical and theoretical study. Final report

Description: The objectives of this research were to: (1) examine empirically the aerosol effect on Umkehr ozone profiles using SAGE II aerosol and ozone data; (2) examine theoretically the aerosol effect on Umkehr ozone profiles; (3) examine the differences between SAGE II ozone profiles and both old- and new-format Umkehr ozone profiles for ozone-trend information; (4) reexamine SAGE I-Umkehr ozone differences with the most recent version of SAGE I data; and (5) contribute to the SAGE II science team.
Date: September 15, 1997
Creator: Newchurch, M.
Partner: UNT Libraries Government Documents Department
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Potential Impacts of Climate Change on Tropospheric Ozone in California: A Preliminary Episodic Modeling Assessment of the Los Angeles Basin and the Sacramento Valley

Description: In this preliminary and relatively short modeling effort, an initial assessment is made for the potential air quality implications of climate change in California. The focus is mainly on the effects of changes in temperature and related meteorological and emission factors on ozone formation. Photochemical modeling is performed for two areas in the state: the Los Angeles Basin and the Sacramento Valley.
Date: January 1, 2001
Creator: Taha, Haider
Partner: UNT Libraries Government Documents Department
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Carbon Dioxide Analysis Center and World Data Center-A for Atmospheric Trace Gases fiscal year 1997 annual report

Description: Fiscal year (FY) 1997 was another exciting and productive one for the Carbon Dioxide Information Analysis Center (CDIAC) at the Oak Ridge National Laboratory. During FY 1997, CDIAC launched the Quality Systems Science Center for the North American Research Strategy for Tropospheric Ozone (NARSTO). The purpose of NARSTO--a US-Canada-Mexico initiative of government agencies, industry, and the academic research community--is to improve the understanding of the formation and transport of tropospheric ozone.
Date: March 1, 1998
Creator: Burtis, M. D.; Cushman, R. M.; Boden, T. A.; Jones, S. B.; Kaiser, D. P. & Nelson, T. R.
Partner: UNT Libraries Government Documents Department
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Exposure information in environmental health research: Current opportunities and future directions for particulate matter, ozone, and toxic air pollutants

Description: Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health-effects studies for air pollution. Air pollution epidemiology, risk assessment, health tracking and accountability assessments are examples of health-effects studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factors data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in order to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges and recommendations identified by the exposure working group, who used cases studies of particulate matter, ozone, and toxic air pollutant exposure to evaluate health-effects for air pollution. One of the over-arching lessons of this workshop is that obtaining better exposure information for these different health-effects studies requires both goal-setting for what is needed and mapping out the transition pathway from current capabilities to meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another over-arching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media monitoring, and/or personal exposure modeling. However, emerging research reveals that the greatest progress comes from integration among two or more of these efforts.
Date: February 1, 2007
Creator: McKone, Thomas E.; Ryan, P. Barry & Ozkaynak, Haluk
Partner: UNT Libraries Government Documents Department
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Catching Our Breath: Next Steps for Reducing Urban Ozone

Description: This report on urban ozone was requested by the Senate Committee on Environment and Public Works, the House Committee on Energy and Commerce, and its Subcommittee on Health and the Environment in anticipation of the upcoming reauthorization of the Clean Air Act. Of the air pollutants that the Act covers, ozone has been the most difficult to bring under control; it may well be the most expensive.
Date: July 1989
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department
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A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

Description: This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.
Date: August 1, 1995
Creator: Wong, A.Y.
Partner: UNT Libraries Government Documents Department
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Investigation of the effect of natural phenomena and industrial activity on stratospheric ozone trends. Final report, September 1993--June 1998

Description: The long term goal of this work is to separate the effects of natural variability and anthropogenic emissions on the chemical composition of the atmosphere. In particular, the authors are concerned with the variability of ozone in the stratosphere and the supply of ozone from the stratosphere to the upper troposphere. During the first phase of this project the authors developed an interactive two-dimensional (2D) model of the dynamics, radiation, and chemistry of the stratosphere. The most important features of the model are the use of the full primitive equations in two dimensions, small horizontal mixing in the tropical regions and small mechanical damping in the lower stratosphere. As a result, transport in the tropics and the mass exchange between the tropics and midlatitude are controlled advectively.
Date: December 1, 1998
Creator: McElroy, Michael B. & Schneider, Hans R.
Partner: UNT Libraries Government Documents Department
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Modeling pollutant penetration across building envelopes

Description: As air infiltrates through unintentional openings in building envelopes, pollutants may interact with adjacent surfaces. Such interactions can alter human exposure to air pollutants of outdoor origin. We present modeling explorations of the proportion of particles and reactive gases (e.g., ozone) that penetrate building envelopes as air enters through cracks and wall cavities. Calculations were performed for idealized rectangular cracks, assuming regular geometry, smooth inner crack surface and steady airflow. Particles of 0.1-1.0 {micro}m diameter are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or larger, assuming a pressure difference of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles are significantly removed by means of gravitational settling and Brownian diffusion, respectively. In addition to crack geometry, ozone penetration depends on its reactivity with crack surfaces, as parameterized by the reaction probability. For reaction probabilities less than {approx}10{sup -5}, penetration is complete for cracks heights greater than 1 mm. However, penetration through mm scale cracks is small if the reaction probability is {approx}10{sup -4} or greater. For wall cavities, fiberglass insulation is an efficient particle filter, but particles would penetrate efficiently through uninsulated wall cavities or through insulated cavities with significant airflow bypass. The ozone reaction probability on fiberglass fibers was measured to be 10{sup -7} for fibers previously exposed to high ozone levels and 6 x 10{sup -6} for unexposed fibers. Over this range, ozone penetration through fiberglass insulation would vary from >90% to {approx}10-40%. Thus, under many conditions penetration is high; however, there are realistic circumstances in which building envelopes can provide substantial pollutant removal. Not enough is yet known about the detailed nature of pollutant penetration leakage paths to reliably predict infiltration into real buildings.
Date: April 1, 2001
Creator: Liu, De-Ling & Nazaroff, William W.
Partner: UNT Libraries Government Documents Department
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Ozone Removal by Filters Containing Activated Carbon: A Pilot Study

Description: This study evaluated the ozone removal performance of moderate-cost particle filters containing activated carbon when installed in a commercial building heating, ventilating, and air conditioning (HVAC) system. Filters containing 300 g of activated carbon per 0.09 m2 of filter face area were installed in two 'experimental' filter banks within an office building located in Sacramento, CA. The ozone removal performance of the filters was assessed through periodic measurements of ozone concentrations in the air upstream and downstream of the filters. Ozone concentrations were also measured upstream and downstream of a 'reference' filter bank containing filters without any activated carbon. The filter banks with prefilters containing activated carbon were removing 60percent to 70percent of the ozone 67 and 81 days after filter installation. In contrast, there was negligible ozone removal by the reference filter bank without activated carbon.
Date: September 1, 2009
Creator: Fisk, William; Spears, Mike; Sullivan, Douglas & Mendell, Mark
Partner: UNT Libraries Government Documents Department
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Analytical Method for the Detection of Ozone Depleting Chemicals (ODC) in Commercial Products Using a Gas Chromatograph with an Electron Capture Detector (GC-ECD)

Description: This document describes an analytical procedure that was developed for the trace level detection of residual ozone depleting chemicals (ODC) associated with the manufacture of selected commercial products. To ensure the United States meets it obligation under the Montreal Protocol, Congress enacted legislation in 1989 to impose an excise tax on electronic goods imported into the United States that were produced with banned chemicals. This procedure was developed to technically determine if residual ODC chemicals could be detected on electronic circuit boards. The analytical method utilizes a “purge and trap” technique followed by gas chromatography with electron capture detection to capture and analyze the volatile chemicals associated with the matrix. The method describes the procedure, the hardware, operating conditions, calibration, and quality control measures in sufficient detail to allow the capability to be replicated. This document corresponds to internal Standard Operating Procedure (SOP) EFL-130A, Rev 4.
Date: August 1, 2008
Creator: Lee, Richard N.; Dockendorff, Brian P. & Wright, Bob W.
Partner: UNT Libraries Government Documents Department
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Aircraft Cabin Environmental Quality Sensors

Description: The Indoor Environment Department at Lawrence Berkeley National Laboratory (LBNL) teamed with seven universities to participate in a Federal Aviation Administration (FAA) Center of Excellence (COE) for research on environmental quality in aircraft. This report describes research performed at LBNL on selecting and evaluating sensors for monitoring environmental quality in aircraft cabins, as part of Project 7 of the FAA's COE for Airliner Cabin Environmental Research (ACER)1 effort. This part of Project 7 links to the ozone, pesticide, and incident projects for data collection and monitoring and is a component of a broader research effort on sensors by ACER. Results from UCB and LBNL's concurrent research on ozone (ACER Project 1) are found in Weschler et al., 2007; Bhangar et al. 2008; Coleman et al., 2008 and Strom-Tejsen et al., 2008. LBNL's research on pesticides (ACER Project 2) in airliner cabins is described in Maddalena and McKone (2008). This report focused on the sensors needed for normal contaminants and conditions in aircraft. The results are intended to complement and coordinate with results from other ACER members who concentrated primarily on (a) sensors for chemical and biological pollutants that might be released intentionally in aircraft; (b) integration of sensor systems; and (c) optimal location of sensors within aircraft. The parameters and sensors were selected primarily to satisfy routine monitoring needs for contaminants and conditions that commonly occur in aircraft. However, such sensor systems can also be incorporated into research programs on environmental quality in aircraft cabins.
Date: May 6, 2010
Creator: Gundel, Lara; Kirchstetter, Thomas; Spears, Michael & Sullivan, Douglas
Partner: UNT Libraries Government Documents Department
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INFLUENCE OF ELEVATED OZONE AND CARBON DIOXIDE ON INSECT DENSITIES.

Description: The combustion of fossil fuels is profoundly altering the chemical composition of the atmosphere. Beginning with the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has increased from approximately 280 to 370 {micro}l l{sup -1} in 2004, and it is expected to exceed 550 {micro}l l{sup -1} by 2050. Tropospheric ozone has risen even more rapidly than CO{sub 2} and average summer concentrations in the Northern Hemisphere are expected to continue to increase by 0.5-2.5% per year over the next 30 years. Although elevated CO{sub 2} stimulates photosynthesis and productivity of terrestrial ecosystems, ozone (O{sub 3}) is deleterious. In addition to directly affecting the physiology and productivity of crops, increased concentrations of tropospheric CO{sub 2} and O{sub 3} are predicted to lower the nutritional quality of leaves, which has the potential to increase herbivory as insects eat more to meet their nutritional demands. We tested the hypothesis that changes in tropospheric chemistry affect the relationship between plants and insect herbivores by changing leaf quality. The susceptibility to herbivory of soybean grown in elevated CO{sub 2} or O{sub 3} was examined using free air gas concentration enrichment (SoyFACE). FACE technology has the advantage that plants are cultivated under realistic field conditions with no unwanted alteration of microclimate or artificial constraints on the insect community.
Date: January 5, 2005
Creator: DeLucia, Evan H.; Dermody, Orla; O'Neill, Bridget; Aldea, Mihai; Hamilton, Jason G.; Zangerl, Arthur R. et al.
Partner: UNT Libraries Government Documents Department
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THE IMPACT OF OZONE ON THE LOWER FLAMMABLE LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE

Description: The Savannah River Site, in conjunction with AREVA Federal services, has designed a process to treat dissolved radioactive waste solids with ozone. It is known that in this radioactive waste process, radionuclides radiolytically break down water into gaseous hydrogen and oxygen, which presents a well defined flammability hazard. Flammability limits have been established for both ozone and hydrogen separately; however, there is little information on mixtures of hydrogen and ozone. Therefore, testing was designed to provide critical flammability information necessary to support safety related considerations for the development of ozone treatment and potential scale-up to the commercial level. Since information was lacking on flammability issues at low levels of hydrogen and ozone, a testing program was developed to focus on filling this portion of the information gap. A 2-L vessel was used to conduct flammability tests at atmospheric pressure and temperature using a fuse wire ignition source at 1 percent ozone intervals spanning from no ozone to the Lower Flammable Limit (LFL) of ozone in the vessel, determined as 8.4%(v/v) ozone. An ozone generator and ozone detector were used to generate and measure the ozone concentration within the vessel in situ, since ozone decomposes rapidly on standing. The lower flammability limit of hydrogen in an ozone-oxygen mixture was found to decrease from the LFL of hydrogen in air, determined as 4.2 % (v/v) in this vessel. From the results of this testing, Savannah River was able to develop safety procedures and operating parameters to effectively minimize the formation of a flammable atmosphere.
Date: January 23, 2013
Creator: Sherburne, Carol; Osterberg, Paul; Johnson, Tom & Frawely, Thomas
Partner: UNT Libraries Government Documents Department
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