Dissertations / Theses: 'Atmospheric ozone Tropospheric chemistry'

1

Martínez, José Enrique. "Impact of natural and anthropogenic hydrocarbons on tropospheric ozone production : results from automated gas chromatography." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/25692.

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Chen, Gao. "A study of tropospheric photochemistry in the subtropical/tropical North and South Atlantic." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/25887.

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3

Pinot, de Moira John C. "Laser studies of atmospheric chemistry." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299100.

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Carpenter, Ian W. "Time resolved studies of reative transients of importance in atmospheric chemistry and chemical vapour decomposition." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318584.

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5

Kotchenruther, Robert A. "Ozone photochemistry in the Northeastern Pacific troposphere and the impacts of trans-pacific pollution transport /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8563.

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Richardson, Jennifer Lynn. "The role of biogenic hydrocarbons in the photochemical production of tropospheric ozone in the Atlanta, Georgia region." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/25769.

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7

Williams, Jonathan M. J. "A study of the atmospheric chemistry of alkyl nitrates." Thesis, University of East Anglia, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241517.

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8

Zeng, Tao. "Three-dimensional model analysis of tropospheric photochemical processes in the Arctic and northern mid-latitudes." Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08232005-123814/.

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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006.
Wang, Yuhang, Committee Chair ; Black, Robert, Committee Member ; Curry, Judith, Committee Member ; Huey, Greg, Committee Member ; Russell, Armistead G, Committee Member. Includes bibliographical references.

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9

Cohan, Daniel Shepherd. "Photochemical Formation and Cost-Efficient Abatement of Ozone: High-Order Sensitivity Analysis." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-09152004-150617/unrestricted/cohan%5Fdaniel%5Fs%5F200412%5Fphd.pdf.

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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2005.
Russell, Armistead G., Committee Chair ; Chameides, William L., Committee Member ; Wang, Yuhang, Committee Member ; Noonan, Douglas, Committee Member ; Chang, Michael E., Committee Member. Vita. Includes bibliographical references.

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Carpenter, Lucy J. "Measurements of peroxy radicals in clean and polluted atmospheres." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317982.

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Zeng, Tao. "Three-Dimensional Model Analysis of Tropospheric Photochemical Processes in the Arctic and Northern Mid_Latitudes." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7648.

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Halogen-driven ozone and nonmethane hydrocarbon losses in springtime Arctic boundary layer are investigated using a regional chemical transport model (CTM). Surface observation of O3 at Alert and Barrow and aircraft observations of O3 and hydrocarbons during the TOPSE experiment from February to May in 2000 are analyzed. We prescribe halogen radical distributions based on GOME BrO observations and calculated or observed other halogen radical to BrO ratios. GOME BrO shows an apparent anti-correlation with surface temperature over high BrO regions. At its peak, area of simulated near-surface O3 depletions (O3 LT 20ppbv) covers GT 50% of the north high latitudes. Model simulated O3 losses are in agreement with surface and aircraft O3 observations. Simulation of halogen distributions are constrained using aircraft hydrocarbon measurements. We find the currently chemical mechanism overestimate the Cl/BrO ratios. The model can reproduce the observed halogen loss of NMHCs using the empirical Cl/BrO ratios. We find that the hydrocarbon loss is not as sensitive to the prescribed boundary layer height of halogen as that of O3, therefore producing a more robust measure for evaluating satellite column measurement. Tropospheric tracer transport and chemical oxidation processes are examined on the basis of the observations at northern mid-high latitudes and over the tropical Pacific and the corresponding global 3D CTM (GEOS-CHEM) simulations. The correlation between propane and ethane/propane ratio is employed using a finite mixing model to examine the mixing in addition to the OH oxidations. At northern mid-high latitudes the model agrees with the observations before March. The model appears to overestimate the transport from lower to middle latitudes and the horizontal transport and mixing at high latitudes in May. Over the tropical Pacific the model reproduces the observed two-branch slope values reflecting an underestimate of continental convective transport at northern mid-latitudes and an overestimate of latitudinal transport into the tropics. Inverse modeling using the subsets of observed and simulated data is more reliable by reducing (systematic) biases introduced by systematic model transport model transport errors. On the basis of this subset we find the model underestimates the emissions of ethane and propane by 14 5%.

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Price, Heather Umbehocker. "Photochemical processing of long range transported Eurasian pollution in the Northeast Pacific troposphere /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/8645.

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Keeton, William J. "Analytical Approaches in Investigating the Kinetics of Water-Molecule Complexes in Tropospheric Reactions." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5527.

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Ozone is a heavily monitored pollutant. Ozone is not directly emitted into the atmosphere, but rather the product of chemical reactions. Ground level ozone occurs when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with each other in the presence of sunlight. The primary precursors of ozone are anthropogenically emitted, and as a result, tropospheric ozone has cost millions of dollars in damages and has hurt the health of countless people. This dissertation is a collection of work that aims to provide insight into atmospheric reactions that result in tropospheric ozone and the instrumentation to study such reactions. While these reactions are well studied, this research is novel in its attempt to understand water vapor's influence in tropospheric ozone reactions. As the troposphere continues to get warmer and wetter from global climate change, water vapor will play a larger role in tropospheric reactions, which in turn may perturb the global reactions. Work is presented on the self-reaction of β-hydroxyethyl peroxy radical (β-HEP), an ozone precursor, and the increase in reaction rate catalyzed by water vapor. β-HEP serves as a model system for understanding the roles of water vapor in perturbing the kinetics and product branching ratio of ozone forming reactions. The self-reaction rate coefficient of β-HEP was investigated between 274-296 K with 1.0 × 1015 to 2.5 × 1017 molecules cm-3 of water vapor at 200 Torr total pressure by slow-flow laser flash photolysis coupled with UV time-resolved spectroscopy and long-path, wavelength-modulated, diode-laser spectroscopy. The overall rate constant is expressed as the product of temperature-dependent and water vapor-dependent terms giving k(T,H2O) = 7.8 × 10-14(e8.2 (±2.5) kJ/RT )(1 + 1.4 × 10-34 × e92 (±11) kJ/RT [H2O]). The results suggest that formation of a β-HEP-H2O complex is responsible for the observed water vapor enhancement of the self-reaction rate coefficient. A new discharge flow mass-spectrometer was engineered in collaboration with the California Institute of Technology and NASA's Jet Propulsion Laboratory. This instrument allows for rapid study of water vapor influence on the kinetics of atmospheric reactions. This instrument will be used in further studying the β-HEP + NO reaction as a function of water vapor concentration.

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Bain, Emily C. "Clean Air in South Texas: An Estimation of Biogenic Tropospheric Ozone Precursors Using Various Models." Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1033659160.

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15

Shim, Changsub. "Constraining global biogenic emissions and exploring source contributions to tropospheric ozone modeling applications /." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-06222006-060856/.

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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007.
Wang Yuhang, Committee Chair ; Cunnold Derek, Committee Member ; Weber Rodney, Committee Member ; Nenes Athanasios, Committee Member ; Guillas Serge, Committee Member.

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Leather, Kimberley. "Tropospheric ozone and photochemical processing of hydrocarbons : laboratory based kinetic and product studies." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/tropospheric-ozone-and-photochemical-processing-of-hydrocarbons-laboratory-based-kinetic-and-product-studies(39b76a99-2358-4db2-be58-baa75d18efea).html.

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Laboratory based temperature-dependent kinetics and product yields for alkene ozonolysis and the reaction of CH3O2 with ClO and BrO have been measured via chamber studies and a turbulent flow tube coupled to CIMS (Chemical Ionisation Mass Spectrometry). In order to gain a better understanding of the fate of the products formed during hydrocarbon oxidation and their subsequent impact on the ozone budget (and so the oxidising capacity of the atmosphere) it is imperative to know the rate at which these reactions proceed and to identify their product yields. As tropospheric temperature varies, Arrhenius parameters were determined during the ozonolysis of selected alkenes. The temperature dependent kinetic database was extended and the activation energies for the ozonolysis of selected alkenes were correlated with an existing SAR (Structure Activity Relationship). Given the myriad organic species in the atmosphere, SARs are useful tools for the prediction of rate coefficients. Inclusion of Arrhenius parameters into the SAR allows for prediction over a range of temperatures, improving the conditions reflected in models. Achieving mass balance for alkene ozonolysis has proven to be a difficult challenge considering the numerous pathways of the Criegee Intermediate (CI). The product yield of formic acid – an organic acid with significant atmospheric implications which is under predicted by models – was determined as a function of relative humidity during ethene ozonolysis. This reaction exhibited a strong water dependence which lead to the prediction of the reaction rate of the CI with water which ranges between 1 × 10-12 – 1 × 10-15 cm3 molecule-1 s-1 and will therefore dominate its loss with respect to bimolecular processes in the atmosphere. Peroxy radicals, strongly influence the total oxidising capacity of the troposphere. The reaction of peroxy radicals with halogen oxides is recognised to be responsible for considerable ozone depletion in the atmosphere, exacerbated by reactive halogens (X, XO) taking part in catalytic cycles. Arrhenius parameters were determined for ClO + CH3O2 and BrO + CH3O2. Temperature is an important parameter affecting rate, exemplified here as the reaction involving ClO exhibited a positive temperature dependence whereas for BrO a negative temperature dependence was evident. As a consequence, the impact of ClO + CH3O2 with respect to ozone loss is diminished. Global modelling predicts a reduction in ozone loss by a factor of around 1.5 and implicates regions such as clean marine environments rather than the polar stratosphere. Conversely, a more pronounced temperature dependence for the reaction of BrO with CH3O2 placed particular importance on lower stratospheric chemistry where the modelled CH3O2 oxidation is doubled. The main products for this reaction were identified to be HOBr and CH2O2. The decomposition of CH2O2 could enhance HOx in the lower and middle stratosphere and contribute to a significant source of HOx in the upper troposphere. Bimolecular reaction of CH2O2 with water could also provide a none negligible source HC(O)OH in the upper troposphere. Alkenes and peroxy radicals undergo chemical processing in the atmosphere whilst acting as a source and sink of ozone and thus can impose detrimental effects on the biosphere, climate and air quality of the Earth.

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17

Parrella, Justin. "Bromine Chemistry in the Present-Day and Pre-Industrial Troposphere: Implications from Modeling and Satellite Observations." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10267.

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This dissertation investigates the impact of bromine on tropospheric ozone, OH, and mercury in the preindustrial and present-day atmosphere through use of modeling and observations from satellite. We developed bromine simulation capabilities coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Standard gas-phase mechanisms for bromine chemistry were unable to reproduce recent estimates of tropospheric BrO from satellite. Agreement was improved significantly after imposing HBr+HOBr heterogeneous chemistry in the model. Under present-day conditions, we find that bromine decreases ozone by 6.5%, < 1 – 8 ppb, and global mean OH by 4%. Most ozone loss is due to HOBr production and photolysis, with additional contributions from \(NO_x\) and ozone loss through \(BrNO_3\) hydrolysis. Simulations of the pre-industrial atmosphere are important as baselines for ozone air quality and radiative forcing calculations. However, standard models for the pre-industrial overestimate ozone observations taken a century ago at Montsouris and cannot reproduce the observed aseasonality. We find that bromine chemistry significantly improves this agreement. However, bromine chemistry has negligible impact on the ozone radiative forcing, as concentrations of BrO remain similar. Despite the small change in BrO concentrations, lower ozone in the preindustrial leads to a 40% greater Br mixing ratios. We estimate that this change may have increased the lifetime of atmospheric Hg(0) against oxidation to Hg(II) by 70% since the pre-industrial, making atmospheric mercury a more global pollutant. Additionally, we develop a retrieval algorithm for stratospheric profiles of BrO number density from SCIAMACHY limb near-UV observations. Zonal means of our BrO profile retrievals throughout April 2008 show common features expected from stratospheric photochemistry and dynamics. We apply simulated \([BrO]/[Br_y]\) ratios to the BrO profile retrievals and estimate a stratospheric loading of \(23.5 \pm 6 ppt Br_y\). This supports the 23 ppt stratospheric \(Br_y\) assumed in the satellite-derived climatology of tropospheric BrO that we used to evaluate our GEOS-Chem simulation. Our results imply \(7 \pm 6 ppt\) Br from short-lived bromocarbons, at the higher end of the 3 – 8 ppt range suggested by observations.
Engineering and Applied Sciences

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18

Murray, Lee Thomas. "Factors Controlling Variability in the Oxidative Capacity of the Troposphere on Interannual to Interglacial Time Scales." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11034.

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This thesis explores the natural forces controlling variability of the tropospheric oxidants on interannual to glacial-interglacial time scales. The oxidants (primarily OH and ozone) determine the lifetime of many trace gases of human interest, including air pollutants and long-lived greenhouse gases such as methane. The oxidants respond to meteorological conditions, precursor emissions (natural and anthropogenic), and surface and overhead stratospheric boundary conditions, all of which have changed since the Last Glacial Maximum (LGM; ~21ka). This dissertation first examines in mechanistic detail the effect of variability in the lightning source of nitrogen oxides \((NO_x)\) precursors on interannual variability (IAV) of the oxidants in the recent past. An optimized technique is presented to constrain the lightning \(NO_x\) source in the GEOS-Chem global chemical transport model (CTM) to time-varying satellite data from the Lightning Imaging Sensor. This constraint improves the ability of the CTM to reproduce observed IAV in 9-year (1998-2006) hindcasts of tropical ozone and OH. IAV in ozone and OH is more sensitive to lightning than to biomass burning, despite greater IAV in \(NO_x\) from the latter source. The sensitivity of OH to lightning reflects positive chemical feedbacks on ozone production, \(HO_x\) recycling, and loss frequencies. This dissertation next introduces an offline-coupled climate-biosphere-chemistry framework for determining oxidant levels at and since the LGM. Detailed simulations of tropospheric composition are performed by GEOS-Chem driven by meteorological fields from the GISS ModelE general circulation model, land cover from the BIOME4-TG global terrestrial equilibrium vegetation model, and fire emissions from the LMfire model. Time slice simulations are presented for the present day, preindustrial, and two different possible representations of the LGM climate. Sensitivity of the results to uncertainty in lightning and biomass burning emissions is tested. Though well-buffered, all simulations find net reduced oxidative capacities relative to the present day. The most important parameters for controlling tropospheric oxidants over glacial-interglacial periods are changes in overhead ozone, tropospheric \(H_2O\), and lightning. The results are discussed in the context of the ice-core record, particularly for methane.
Engineering and Applied Sciences

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19

Kentarchos, Anastasios S. "Background tropospheric ozone over Europe." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361428.

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Menezes, Kim Anne. "Bayesian spatial models : applications for tropospheric ozone data /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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21

Banerjee, Antara. "Drivers of future stratospheric and tropospheric ozone." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/283974.

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22

Kinnison, David J. A. "Tropospheric chemistry of halogenated organic compounds." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240663.

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Lai, I. C. "The relationship between tropospheric ozone and atmospheric circulation in Taiwan." Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/10584/.

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The aim of the study is to investigate the relationship between variability in tropospheric ozone in Taiwan and the regional atmospheric circulation, paying particular attention to the influence of long-range transport on ozone pollution levels. The study period is 1994 to 2004. The data used in this study include air pollution data from the Taiwan Air Quality Monitoring Network and NCEP/NCAR reanalysis data. The spatial and temporal variations in weather types have been characterised using an objective circulation classification scheme and relationships with episodes of high ozone levels over Taiwan have been determined. The signature of the large-scale atmospheric circulation associated with high ozone pollution and the connection with long-range transport of ozone precursors and ozone have been identified using spatial composites and back-trajectory analysis. Trajectories were calculated using the Hybrid Single-Particle Integrated Trajectory model. The air pollution data analysis shows that Taiwan experiences a seasonal cycle in ozone levels, with maxima in spring and autumn and a minimum in summer. The spatial composite and back trajectory analyses indicate that long-range transport does play a role in increasing high ozone episodes in Taiwan. A link with the seasonal variation of the monsoon circulations at different times is shown, with a weaker summer monsoon and a stronger winter monsoon circulation associated with enchanced ozone levels over Taiwan. The characteristics of atmospheric circulation for ozone pollution episodes include enhanced north and northeasterly flows, originating from nearby polluted areas and suggest that mainland China, Korea and Japan are source regions of ozone and its precursors for Taiwan. Moreover, the transport pathways at the high level of 2000m show that the southern China is also prominent source region, which is a previously unidentified distant source of ozone pollution in Taiwan. It is suggested that the increase of ozone pollution in summer found in this study is caused by a weaker summer monsoon circulation in recent years. While it is emphasised that variability in long-range transport is the only factor affecting ozone pollution levels over Taiwan, the influence of global warming on the Asian monsoon circulation and, hence, long-range transport of ozone and its precursors warrants serious consideration.

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24

Yang, Qing. "Derivation of tropospheric column ozone using the TOR approach and mapping technique." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19748.

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Thesis (Ph.D)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2008.
Committee Chair: Derek M. Cunnold; Committee Member: Michael Bergin; Committee Member: Ray Wang; Committee Member: Robert Black; Committee Member: Yuhang Wang.

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25

Duncan, Bryan N. "The effects of urban ozone control strategies on northern hemispheric, midlatitude tropospheric ozone." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/25875.

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Biesenthal, Thomas Anthony. "The role of carbonyl compounds in tropospheric ozone chemistry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22886.pdf.

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27

Reeves, Claire E. "A theoretical study of the nonmethane hydrocarbons on tropospheric ozone production in the Northern Hemisphere." Thesis, University of East Anglia, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235639.

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Gao, Huaizhu. "Temporal and spatial statistical analyses of tropospheric ozone, NOx dynamics and heavy-duty truck transportation activities in southern California /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.

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Thesis (Ph. D.)--University of California, Davis, 2004.
Degree granted in Civil and Environmental Engineering. Includes bibliographical references. Also available online. (Restricted to UC campuses)

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Wild, James Oliver Felix. "Some problems in the numerical modelling of tropospheric chemistry." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388385.

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30

Whyte, Lynden J. "A kinetic and mechanistic study of tropospheric reactions." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314391.

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Squire, Oliver John. "Influence of changes in climate and land use on isoprene emissions and tropospheric ozone." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709319.

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32

Engle, Mark Alan. "The influence of tropospheric ozone, hydrothermal systems, and fires on atmospheric mercury emissions from natural sources /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3209132.

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Thesis (Ph. D.)--University of Nevada, Reno, 2005.
"December 2005." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.

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Thompson, Katherine C. "Aspects of the tropospheric chemistry of halogenated compounds and chlorine atoms." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302490.

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Crowther, Richard Antony. "Modelling tropospheric processes important to the chemistry of ozone in the North Atlantic region." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390651.

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Hickson, Kevin Michael. "A study of several reactions relevant to atmospheric ozone chemistry." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343854.

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Hsiang, Solomon M. "Ozone chemistry during global glaciations : a possible climate feedback." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/114119.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.
Cataloged from PDF version of thesis. Pages 77-78 missing from original thesis.
Includes bibliographical references (pages 76-84).
A theory for changes in ozone chemistry during late Proterozoic global glaciations is developed. The possible significance of temperature, humidity, nitrogen oxides, reactive chlorine, lightning frequency, surface deposition and albedo as altered constraints on ozone processes is discussed. An elementary box model is developed by the author to make first order judgments regarding the significance of chemistry changes on ozone concentrations and its climactic effect. A one dimensional photochemical-transport model (Kasting, 1995) was used to more precisely determine the effects of global glaciations on ozone concentrations up to 5 hPa in several latitude bands. Reduced NO₂ availability in the stratosphere seems to dominate ozone's response (positive anomalies) in the stratosphere. Low temperatures, low humidity, reduced lighting frequency and altered chlorine and nitrogen chemistry collectively reduce ozone presence in the troposphere, however the overall sign of the tropospheric ozone anomaly depends heavily on poorly characterized deposition rates. With output from the one-dimensional photochemistry model, a time-varying ozone concentration field was assembled for the entire planet and used in snowball runs of the General Circulation Model (NCAR Community Atmosphere Model 3.0). These runs were compared to a controlled snowball run with a modern ozone field to discern the climactic significance of altered ozone. Results suggest that ozone concentrations during global glaciations might directly produce global average surface radiation anomalies of -1.5 ~ 1.5 W/m² , resulting in global average surface temperature anomalies of -0.5 ~ 0.5°K. Magnitude and sign uncertainties result from poorly known deposition rates for ozone over frozen surfaces and the simplicity of the modeling technique. The indirect effect of increasing stratospheric ozone, i.e. a reduction in atmospheric oxidative capacity, may result in positive anomalies of other green house gasses and is discussed as an area for further research.
by Solomon M. Hsiang.
S.B.

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37

Wilson, Craig. "Theoretical studies of reactions of reduced sulfur compounds of importance in the troposphere." Thesis, University of Warwick, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263786.

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DiNunno, Brian J. "An assessment of tropospheric photochemistry over central/eastern North Pacific." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/26281.

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Singh, Ajit. "Quantifying the effect of atmospheric pollution and meteorology on visibility and tropospheric chemistry." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7828/.

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There are two distinct research foci within this thesis; the role of aerosol particle and trace gases on (i) visibility and (ii) tropospheric chemistry. This work investigates short and long term visibility, by exploring the combined influence of atmospheric aerosol and meteorology. Observations were fitted to a newly developed light extinction model to generate predictions of historic aerosol and gas scattering and absorbing properties, explaining long term visibility trends and their dependence on meteorological conditions. This model incorporates parameterizations of aerosol hygroscopicity, gas absorption and particle concentration, scattering, and absorption. Historical visibility data can therefore be used to assess trends in aerosol particle properties for time periods when observational data are scarce or non-existent. Short term visibility variations caused by particulate matter from firework and bonfire emissions is presented. It is shown that a reduction in the atmospheric visibility nationwide is -25%; which is a consequence of increased loading of atmospheric PM, and is found to be dependent upon relative humidity. Within tropospheric chemistry, HONO is an important source of OH radicals, and daytime HONO sources are poorly constrained. This work explores the abundance of HONO during a solar eclipse as a natural short-term perturbation to atmospheric photochemistry. A chemical kinetic model is employed to predict the concentrations of HONO using different source scenarios. The study provides insights into the variation of HONO with meteorology, traffic emission and other source.

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Kim, Judy E. (Judy Eunhee). "Physical chemistry of acid systems relevant to stratospheric ozone depletion." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/54401.

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41

Bednarz, Ewa Monika. "Chemistry-climate modelling studies of decadal and interdecadal variability in stratospheric ozone and climate : the 11-year solar cycle and future ozone recovery." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274359.

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The Earth’s atmosphere constitutes a complex system subject to a large number of forcings of both natural and anthropogenic origin; these influence its evolution on a range of timescales. This thesis makes use of the UMUKCA global chemistry-climate model to explore several aspects relating to the atmospheric response to the 11-year solar cycle forcing and future stratospheric ozone recovery. Firstly, following recent improvements in the model, the atmospheric response to the solar cycle forcing simulated in UMUKCA is discussed. It is shown that while some features show a broad resemblance to observations/reanalysis, there are clear differences with regard to other features; the latter could result from model deficiencies and/or uncertainties in the observed response. The role of analysis method and of interannual variability is also addressed. Secondly, the solar cycle response is separated into the individual contributions from direct radiative heating and from ozone production using a set of sensitivity experiments. It is shown that while the tropical yearly mean responses to the two components are generally linearly additive, this is not necessarily the case in the high latitudes. It is suggested that solar-induced ozone changes could be important for modulating the Southern Hemisphere dynamical response. Thirdly, the role of the representation of the solar ozone response is studied. It is shown that the choice of the solar ozone response prescribed in the radiation scheme in non-interactive ozone experiments has a substantial impact on the simulated temperature response to the solar cycle forcing. The Northern Hemisphere dynamical responses are found to be generally similar within the uncertainty. A comparison with an interactive ozone case is also discussed. Lastly, future ozone recovery is investigated using a seven-member ensemble of 1960- 2099/1980-2080 integrations. The long-term evolution of ozone in different regions is found to be generally consistent with previous modelling studies. The long-term trends and variability in springtime Arctic ozone and its chemical, radiative and dynamical drivers are assessed. It is shown that Arctic ozone increases in the future, consistent with future reduction in stratospheric chlorine, stratospheric cooling and strengthening large-scale circulation. Yet, the large interannual variability is found to continue and to facilitate episodic ozone reductions, with halogen chemistry becoming a smaller but non-negligible driver of future springtime Arctic ozone variability for many decades.

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42

Maxwell-Meier, Kari Lynn. "Urban Impacts On Atmospheric Chemistry: Surface Ozone in Large Versus Small Urban Centers and Urban Pollution in Asian Dust Storms." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-08012006-093354/.

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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006.
Rodney J. Weber, Committee Chair ; Michael E. Chang, Committee Member ; Judith A. Curry, Committee Member ; Ellery Ingall, Committee Member ; Michael H. Bergin, Committee Member.

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43

Parrish, Paul David. "Global retrievals of upper-tropospheric phosphine from the Cassini/CIRS Jupiter encounter." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:02252dd8-be35-433e-9b2d-bc12e9332773.

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On December 30th 2000, the Cassini-Huygens spacecraft reached the perijove milestone in its continuing journey to the Saturnian system. During an extended six-month encounter, the Composite Infrared Spectrometer (CIRS) returned spectra of the Jovian atmosphere, rings and satellites from 10 to 1400 cm^-1 (1000 to 7 µm) at a programmable spectral resolution of 0.5 to 15 cm^-1. The improved spectral resolution of CIRS over previous infrared instrument-missions to Jupiter, the extended spectral range and higher signal-to-noise performance provide significant advantages over previous data-sets. Both optimal-estimation retrieval and radiance-differencing are used to investigate the global variation of upper-tropospheric temperature, ammonia, phosphine and cloud opacity between ± 60˚ latitude. The analysis methods are shown to successfully reproduce Jovian conditions with results consistent with previous investigations. The composition results in particular are well characterised and suggest an important role played by mixing and transport within the upper-troposphere. Interpretation and validation of the retrieved results is conducted via the construction of a simple dynamic model incorporating transport, diffusion and (photo)chemistry.

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44

Aliwell, Simon Richard. "Measurement of atmospheric trace gases by absorption spectroscopy." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388668.

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45

Zhang, Renyi. "Laboratory investigations of heterogeneous chemistry important to ozone depletion in the stratosphere." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12219.

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46

Johnson, David. "The kinetics and mechanisms of the gas-phase reactions of ozone with unsaturated compounds." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340021.

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47

Soller, Raenell. "Photochemistry and reaction kinetics of bromine nitrate." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/26223.

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48

Toro, Claudia Andrea. "Photoactive roadways| Laboratory, field and modeling insight on the impact of photocatalytic paving materials on urban tropospheric chemistry." Thesis, Washington State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10139527.

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Photoactive roadways have been suggested as a mitigation method to improve air quality in urban areas. However, difficulties translating laboratory results to real world conditions has complicated a wider adoption of this technology. This work presents a methodology to determine first-order loss coefficients of ozone precursors on photoactive asphalt and concrete using a continuously-stirred tank reactor under different conditions of humidity and UV illumination. The experimental loss coefficients were used to determine uptake coefficients that can be incorporated in air quality models to represent photoactive surfaces.

The laboratory findings indicate that paving materials respond differently to variations in humidity, with concrete efficiency more influenced by the increase in water vapor. The uptake of NO on asphalt was found to have a power dependence with UV irradiance. The uptake of NO₂ was smaller than that of NO, suggesting that any impact on air quality would occur mainly through removal of NO. The uptake of VOC was found to decrease exponentially with the increase in the vapor pressure of the organic compound indicating a competitive adsorption mechanism driving the photocatalytic removal of mixtures. Molar yields of HONO, NO₂ and aldehydes were detected during the removal of pollutants in asphalt, while only NO₂ was detected from concrete, indicating potential disadvantages of TiO₂ treated surfaces.

The use of the CO/NOx molar ratio was explored to monitor changes in NOx levels in experiments performed in an outdoor chamber. CO removal was not observed during the time scale at which NOx removal occurs, suggesting that CO could be used as tracer in field studies to follow changes in vehicle emissions caused by photoactive roads.

The uptake coefficients for NO determined in this work were incorporated in a one-dimensional model to understand the overall impact of photoactive surfaces on atmospheric chemistry. Preliminary results indicate that a moderate reduction of up to 20% in NO could be achieved for a scenario simulating Houston conditions. No significant effect on ozone was observed as result of adding HONO yields. However, further investigation needs to address aldehyde and NO₂ yields to determine if these byproducts offset the benefits of this strategy.

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Urbanski, Shawn P. "Laboratory investigation of the atmospheric oxidation of dimethyl sulfide." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/25724.

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50

Prestbo, Eric Wallace. "Atmospheric chemistry and long-term measurements of peroxyacetyl nitrate and ozone at a remote location in northern New Mexico /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/8634.

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Dissertations / Theses on the topic 'Atmospheric ozone Tropospheric chemistry'

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