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Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology
Ozone And Reactive Oxidized Nitrogen Chemistry In The Northeast U.S, Matthew Ninneman
Ozone And Reactive Oxidized Nitrogen Chemistry In The Northeast U.S, Matthew Ninneman
Legacy Theses & Dissertations (2009 - 2024)
Ongoing reductions in oxides of nitrogen concentrations ([NOx] = nitric oxide ([NO]) + nitrogen dioxide ([NO2])) throughout the continental United States (U.S.) have important implications for tropospheric ozone (O3) and reactive oxidized nitrogen chemistry (NOy ≈ NOx + nitric acid (HNO3) + particle nitrate (pNO3) + peroxy nitrates (PNs) + alkyl nitrates (ANs)). Specifically, decreasing [NOx] concentrations have likely (1) increased the sensitivity of O3 to the [NOx] level, and (2) affected NOy speciation and partitioning. An understanding of the impacts of continued [NOx] reductions is needed to inform current and future air pollution control strategies, especially since the National …
The Clean Air Act And Its Impact On Ground Level Ozone Pollution Levels In Los Angeles, California, Rebecca G. Ford
The Clean Air Act And Its Impact On Ground Level Ozone Pollution Levels In Los Angeles, California, Rebecca G. Ford
Honors Theses
Ozone (O3) occurs naturally as a protective, ultraviolet radiation-shielding “Ozone Layer” in the Stratosphere and as a photochemically produced pollutant in the Troposphere. The Clean Air Act (CAA) of 1970 regulates the emission and concentration of O3 and five other atmospheric pollutants. Since the signing of the CAA, the ongoing question has been whether or not the National Ambient Air Quality Standards (NAAQS) and regulatory policies have had an effect on decreasing O3 concentration. The Los Angeles metropolitan area is a prime example of how O3 can be a public health hazard, and taint a …
Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox
Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox
Electronic Theses and Dissertations
Perchlorate (ClO4) in the environment is of concern, because of potential health risks to humans, among other reasons. Evidence suggests that the majority of environmental perchlorate is formed in the atmosphere (likely in the stratosphere), in chemical processes involving ozone and stratospheric chlorine. A lack of knowledge in regards to the processes has resulted in a limited understanding of the environmental conditions and variables that influence perchlorate production and consequently perchlorate prevalence and variability in the environment. In this study, perchlorate was measured, using an established ion chromatography-‐electrospray ionization-‐tandem mass spectrometry (IC-‐ESI-‐ MS/MS) technique, in over 1,600 snowpit …
Studies Of Arctic Tropospheric Ozone Depletion Events Through Buoy-Borne Observations And Laboratory Studies, John W. Halfacre
Studies Of Arctic Tropospheric Ozone Depletion Events Through Buoy-Borne Observations And Laboratory Studies, John W. Halfacre
Open Access Dissertations
The photochemically-induced destruction of ground-level Arctic ozone in the Arctic occurs at the onset of spring, in concert with polar sunrise. Solar radiation is believed to stimulate a series of reactions that cause the production and release of molecular halogens from frozen, salty surfaces, though this mechanism is not yet well understood. The subsequent photolysis of molecular halogens produces reactive halogen atoms that remove ozone from the atmosphere in these so-called “Ozone Depletion Events” (ODEs). Given that much of the Arctic region is sunlit, meteorologically stable, and covered by saline ice and snow, it is expected that ODEs could be …
Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon
Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon
Open Access Theses
Ozone is an important oxidizer in the atmosphere and plays a crucial role as a cleanser, removing various compounds such NOx and SOx. It also is intriguing to those that study stable isotopes as it has a unique signature found in no other oxygen containing molecule. Ozone is observed to fractionate mass independently, which means it does not follow the typical δ 17 O /δ18 O = 0.52 ratio expected for molecules enriched with 17 O and 18 O. The magnitude of ozone's mass independent enrichment has been studied in laboratory experiments and atmospheric observations but its explanation is still …
Modeling Dynamics Of Ozone And Nitrogen Oxides At Summit, Greenland With A 1-D Process-Scale Model, Keenan Anton Murray
Modeling Dynamics Of Ozone And Nitrogen Oxides At Summit, Greenland With A 1-D Process-Scale Model, Keenan Anton Murray
Dissertations, Master's Theses and Master's Reports - Open
This work presents a 1-D process scale model used to investigate the chemical dynamics and temporal variability of nitrogen oxides (NOx) and ozone (O3) within and above snowpack at Summit, Greenland for March-May 2009 and estimates surface exchange of NOx between the snowpack and surface layer in April-May 2009. The model assumes the surface of snowflakes have a Liquid Like Layer (LLL) where aqueous chemistry occurs and interacts with the interstitial air of the snowpack. Model parameters and initialization are physically and chemically representative of snowpack at Summit, Greenland and model results are compared to …