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Traffic population in the UK has grown by 27% in 2002 and predicted to continue to an estimated 38% in 2016 and up to 60% by 2031. This means vehicular emissions from road transport may account for higher proportion of total emissions of pollutants resulting in air pollution with its attendant consequences. Although poor air quality concerns has often been linked to urban areas, many rural areas apparently have locations where air quality objectives may be threatened especially in the wake of increasing vehicular population. Thus, this elicits the necessity to investigate the relationship between vehicular emissions and air quality. This study investigated the influence of vehicular traffic on a major trunk road on rural air quality through continuous measurements of nitrogen dioxide, sulphur dioxide and hydrocarbon between June 2008 and April 2010 along a major trunk road in a catalogued rural environment in the UK. Collection and analysis of pollutants was by Dräger short-term tubes and Dräger passive diffusion tube techniques. Throughout the sampling period, concentrations of sulphur dioxide were not detected using the short-term tube technique but were detected by the passive diffusion tubes. The study found that variations in mean concentrations of the pollutants were synonymous with traffic frequency and were influenced by meteorological conditions especially wind speed, temperature and relative humidity. Results observed concentration decline trend with increasing distance and showed maximum concentrations during winter, mainly in areas of close proximity to anthropogenic source, and minimum in summer. Values between winter year 1 and winter year 2 monitoring campaigns showed significant difference (P<0.05 and R=0.91) as was in summer year 1 and year 2 (P<0.05 and R=0.94), spring year 1 and year 2 (P<0.05 and R=0.84) and autumn year 1 and year 2 (P<0.05 and R=0.79). When compared with the guidance limits, NO2 Page ii showed exceededance at roadside and 50 m, and at some sample sites, up to 100 m from the road. Conversely, SO2 did not show any exceedance but statistical analyses was mostly significant between concentrations and distance at p≤0.05, suggesting the variability of pollutants, as well as the influence of distance on their temporal and spatial distribution. Results also show that pollutants correlated very well with daily traffic population with strong positive r2 and R-values. Similarly, the study considered the application of hazel leave (Corylus avellana) and ryegrass (Lolium perenne) vegetation samples in monitoring rural air quality. Both samples were collected in different seasons and distances (5m, 50m, and 100m) from the A49 trunk road at four rural sites characterised with diverse traffic densities and anthropogenic activities. The aim was to determine the elemental content and trends within the samples and to investigate the influence of distance from the road, height from ground level, and sampling season on the elemental levels. The levels of Al, As, Ba, Ca, Si, Mg, S, Cd, Cr, Na, Ni, Sb, Se, Sn, Mo, Mn, C, K, P, Cl, Ti, Fe, Zn, and Pb were determined using X-ray fluorescence (XRF), inductively coupled plasma-mass spectrometer (ICP-MS), and Scanning Electron Microscopy-Energy Dispersive X-ray spectrometer (SEM-EDX). Results show that despite the traffic differentials between the sampling sites, the pollution level of heavy metals were generally low in all sampling site and concentrations of Cr, Cu, Ni, Pb, and Ti exhibited inverse relationship with distance, decreasing in levels with increasing distance from the trunk road. Although root uptake from the soil is a potential source of heavy metals, geochemistry research of the study area did not show any evidence that proves any major heavy metals deposit concerns in the soil. It is therefore possible that heavy metal emissions were deposited in a form that was not readily available for root uptake, thereby narrowing the presence of heavy metal pollutants to other potential Page iii sources. However, this study found high level of heavy metals at the roadside measurements in the order of Zn (0.703 ppm) > Ti (0.346 ppm) > Cr (0.111 ppm) > Cu (0.106 ppm) > Pb (0.026 ppm) > Ni (0.025 ppm). They were found in different magnitudes higher than their respective levels at 50 and 100 m from the trunk road and therefore tend to support traffic origin. Findings from this study show that heavy metals exhibited different degree of correlation between individual elements, ranging from very strong positive to weak, as well as negative correlations. Statistical analyses show that the elements predominantly exhibited statistically significant differences between elements and between distances from the road. Overall, findings from this study demonstrate that both vegetation species prove to be successfully useful in determining the pollution status and trends of traffic-related heavy metals.

Emulsified sulfur was found to be the most suitable form of sulfur for in-situ thiosulfate production for sulfite inhibition with a maximum sulfur-to-thiosulfate-conversion of 50 % and t₅₀ of 6 hours. Increasing the ionic strength of the solution reduces the reaction rate between sulfur and sulfite. Reaction rate reduced by 3 when ionic strength of the solution was increased from 0.225 M to 2.95 M. The rate of reaction between sulfur and sulfite was found to be first-order in sulfur, half-order in sulfite, and zero-order in thiosulfate with a reaction rate constant of 5.48 x 10⁻³ mM [superscript -0.5] min⁻¹. Increasing the reaction temperature from 40 to 75 °C increased the interpreted reaction rate by a factor of 17. The activation energy of the reaction was found to be 74.2 kJ/mol, and this high value indicates that the reaction might be kinetically limited and not mass transfer limited. The reaction rate model predicts experimental bench-scale reaction rates with an absolute average deviation of 6.5%. In the pilot-scale prescrubber, at coal conditions, pH was observed to decrease as a function of time with 3 linear regions. These regions corresponded to CO₂ absorption to form carbonate, conversion of carbonate to bicarbonate, and CO₂ liberation from solution by reaction of bicarbonate with SO₂ respectively. The characteristic times of these linear regions corresponded to the rate of the reaction in each of these regions. Rate of oxidation of thiosulfate under 0-1 ppm NO₂ conditions was 0.13 gmol/hr which was half the rate at 0-5 ppm NO₂ conditions. Thiosulfate loss by tank bleed was found to be directly related to the amount of gas processed. Thiosulfate loss by bleed reduced from 60 gmol to 17.2 gmol when the flue gas flow rate reduced by 1/2.25 due to the lesser amount of water condensing in the prescrubber. A minimum of 25 mM sulfite was required to maintain NO₂ removal of 90% even under low NO₂ conditions. At NGCC conditions, thiosulfate degradation rates were 0.112 gmol/hr and 0.127 gmol/hr before and after thiosulfate addition respectively. Sulfite and thiosulfate in the prescrubber increased with SO₂ coming into the prescrubber. Thiosulfate and sulfite were correlated by a power-law relation just as in the coal condition

The last decade has seen frequent occurrences of severe air pollution episodes of high concentration in SO2 during winters in the North China Plain (NCP). Using satellite data from the Ozone Monitoring Instrument (OMI), chemistry transport model (GEOS-Chem) simulations, and National Center for Environmental Predication (NCEP) meteorological reanalyzes, this study examines meteorological and synoptic conditions associated with these air pollution episodes during winters of 2006-2015. OMI-based data suggest a large decrease (~30% in area average) of emission since 2010. Statistical analyzes show that meteorological conditions associated with the top 10% of OMI-based high days are found in average to be controlled by high pressure systems with 2 m s-1 lower wind speeds, slightly warmer, 1-2 °C, temperatures and 10-20% higher relative humidities from the surface to 850 hPa. Numerical experiments with GOES-Chem nested grid simulations at 0.5°´0.667° resolution are conducted for winters of 2009 as a control year, and 2012 and 2013 as years for sensitivity analysis. The experiments reveal that year-to-year winter change of columnar SO2 amount and distribution in first order is linearly proportional to the change of SO2 emission, regardless of the differences in meteorological conditions. In contrast, the surface SO2 amount and distribution exhibit highly non-linear relationships with respect to the emission and stronger dependence on meteorological conditions. Longer data records of atmospheric SO2 from space combined with meteorological reanalyzes are needed to further study the climatology of air pollution and the variations in air pollution events in the context of climate change. Adviser: Jun Wang

The potency of SO2 is highest when it is in a free or unbound state. High concentrations of SO2 binders in wine may greatly diminish the efficacy of SO2. The decreased preservative efficacy of bound SO2 requires increased SO2 additions to wine for adequate preservation action. However, additional sulfite concentrations may increase the risk of adverse health reactions for sensitive consumers and may also exceed legal limits for SO2 in wines. Hence, this work investigated important SO2 binding compounds throughout vinification and developed strategies for their control to increase the preservative efficacy of SO2 and limit total additions to wine. Comprehensive analysis of SO2 binding compounds at practical concentrations was achieved through the development of a novel UHPLC method that used the metal chelator, EDTA, to limit oxidation reactions during sample preparation. This method greatly improved existing protocols limited by complex sampling procedures and long HPLC analysis times. A survey of 237 wines from across NYS showed clear differences in the SO2 binder profiles between different wine types. Red wines were typically higher in [alpha]ketoglutaric acid and galacturonic acid, whereas, white wines were higher in acetaldehyde, pyruvic acid and glucose. Major regulating factors for acetaldehyde production during alcoholic fermentation were SO2 addition prior to inoculation, fermentation temperature and grape must type. With the exception of galacturonic acid, the concentrations of acetaldehyde, pyruvic acid and [alpha]-ketoglutaric acid decreased following inoculation with O. oeni. Overall bound SO2 levels were decreased by 22% during MLF and an additional 53% one week later. During MLF, acetaldehyde bound SO2 increased mean O. oeni lag times in a dose dependant manner. Metabolism of bound SO2 by O. oeni resulted in concomitant increases in free SO2 concentrations, which never rose about 8.0 mg l-1. Malic acid was depleted by O. oeni, despite the presence of acetaldehyde bound SO2. Findings suggest that significant reductions in SO2 binders can be achieved by both yeast and bacterial metabolism during vinification. However, O. oeni growth may be limited by the presence of excessive bound SO2 concentrations. To decrease acetaldehyde levels during cellaring, oxygen ingress should be completely restricted.

Coal fired power plants release large quantities of CO2 and trace amounts of SO2 into the atmosphere, affecting global warming and worldwide climate change. CO2 is a concern as a greenhouse gas in relation to global temperature raise. SO2 is a concern in environmental protection as a precursor for acid rain. The impact of CO2, SO2, and H2S on the environment demonstrate the removal process is a subject of study of great importance. Removal of these gases has been focused on the development of amine based sorbents for sequestration by the adsorption and desorption process. Fourier Transform Infrared spectroscopy (FTIR) is a powerful tool for investigating the adsorption/desorption process and structure of adsorbing molecules. The application of FTIR, coupled with ab initio quantum chemistry, can provide a direct means for understanding the interactions that occur during chemisorption. The removal of CO2 and H2S by an amine based sorbent has been studied. The hypothesis for this study is to investigate the use of polyethylene glycol (PEG) to promote tetraethylenepentamine (TEPA) CO2 and H2S removal capacity. It is thought that the use of PEG may improve the catalytic adsorption capacity through hydrogen bonding. This study used in situ FTIR and ab initio quantum chemistry to investigate the adsorption and desorption processes during CO2 and H2S capture at the molecular level. The FTIR results determine that PEG interacts with the primary amine functional groups of TEPA dispersing the adsorption sites leading to improved adsorption capacity for CO2 and H2S. Ab initio quantum chemistry determined that PEG lowers the binding energy of CO2 and H2S leading to a lower desorption temperature. Removal of the nauseous gas SO2 by an amine based sorbent is studied. The hypothesis investigated the use of 1,3-phenylenediamine low basic property for creating a reusable solid amine based sorbent for SO2 removal. It is thought that the low basic property of the aromatic amine will allow the effective SO2 adsorption and desorption at low temperature. This study used in situ FTIR spectroscopy to investigate the adsorption and desorption processes during SO2 capture. The result of this study determined that 1,3-phenylenediamine basic property allowed SO2 adsorption and desorption at 373 K, however, sorbent deactivation occurs. The in situ UV-Visible spectroscopic technique provided insight that deactivation is the result of agglomeration of 1,3-phenylenediamine. Addition of PEG prevented the agglomeration and improved the adsorption capacity of 1,3-phenylenediamine through hydrogen bonding with the primary amine functional group.Amine based sorbents have been proven as an effective and economic process for the removal of CO2 and the hazardous gases H2S and SO2. Advancing knowledge in the area of amine based sorbents will improve our ability for hazardous waste management. Hazardous waste management may also be achieved by the oxidation and reduction (redox) of toxic materials. TiO2 based catalysts have the ability to oxidize a number of hazardous materials to nontoxic products where TiO2 has become the benchmark semiconductor in photo-detoxification of contaminated water. This work also investigates the photocatalytic dehydrogenation process over TiO2 based catalysts. The hypothesis investigated the relationship of the photogenerated electrons and adsorbed species during the photocatalytic dehydrogenation of 2-propanol. It is thought that the interaction of the photogenerated electrons and adsorb species may be elucidated from the reaction mechanism during the photocatalytic dehydrogenation of 2-propanol. 2-propanol is used as a model compound because it provides a simple and standard way to measure the photo-catalytic activity during the gas/liquid phase reactions. This study suggest that in the presence of adsorbed H2O, the dehydrogenation process proceeded by a hydroxyl radical species while in the absence of adsorbed H2O the active species is an adsorbed ion. Au/TiO2 unique ability to generate adsorbed oxygen ions resulted in higher catalytic activity in the absence of adsorbed H2O under UV-irradiation. The reaction pathway for the photocatalytic dehydrogenation of 2-propanol is strongly dependent on the coverage of surface H2O.

Lanthanum strontium vanadate (LSV), a perovskite ceramic electrocatalyst suitable for use as a solid oxide fuel cell (SOFC) anode, has shown significant activity toward the selective oxidation of H2S from a fuel stream. With this in mind, the feasibility of a two-stage SOFC reaction process using LSV-based SOFCs as an alternative to H2S sorbents was investigated. A procedure for producing a bilayer LSV anode via an inexpensive screen-printing method was optimized and planar SOFCs utilizing these bilayer LSV anodes were tested under H2, syngas and syngas with H2S environments. Considering LSV/yttria stabilized zirconia (YSZ) bilayer anodes, it was found that the optimum anode thickness of 65 μm at 800°C yields a maximum power density of 5.85 mW/cm2, while at 900°C the optimized anode thickness of 80 μm realizes a maximum power density of 17.96 mW/cm2. Substitution of gadolinium-doped ceria (GDC) for YSZ in the bilayer LSV anode was shown to improve catalytic performance; peak power densities for optimized LSV/GDC-based SOFCs at 800 and 900°C were 16.60 and 34.86 mW/cm2, respectively.It was demonstrated that all tested LSV-based SOFCs showed little to no performance degradation due to catalytic poisoning when utilizing syngas containing H2S as fuel, corroborating previous results. It was also shown that LSV had poor activity toward CO oxidation either directly or as a water-gas shift catalyst over the tested temperature range. A feasibility study of the aforementioned two-stage SOFC reaction process showed that SO2 found in the exhaust from the LSV-based SOFC caused performance degradation to a Ni-based SOFC, though not to the extent caused by an equal amount of H2S; this finding suggests that SOFCs utilizing LSV/YSZ anodes may indeed offer promise as a method for warm-gas remediation of H2S contained in hydrocarbon fuel streams.

Sulfide minerals are a major source of metals; however, certain sulfide minerals, such as pyrite and pyrrhotite, are less desirable. Froth flotation is a commonly used separation technique, which requires the use of several reagents to float and depress different sulfide minerals. Xanthate, a thiol collector, has gained immense usage in sulfide minerals flotation. However, some sulfides are naturally hydrophobic and may float without a collector. Iron sulfides, such as pyrite and pyrrhotite, are few of the most abundant minerals, yet economically insignificant. Their existence with other sulfide minerals leads to an inefficient separation process as well as environmental problems, such as acid mine drainage during mining and processing and SO2 emissions during smelting process. A part of the present study is focused on understanding their behavior, which leads to undesired flotation and difficulties in separation. The major reasons for the undesired flotation are attributed to the collectorless hydrophobicity and the activation with heavy metal ions. To better understand the collectorless hydrophobicity of pyrite, Electrochemical Impedance Spectroscopy (EIS) of freshly fractured pyrite electrodes was used to study the oxidation and reduction of the mineral. The EIS results showed that the rate of reaction increases with oxidation and reduction. At moderate oxidizing potentials, the rate of reaction is too slow to replenish hydrophilic iron species leaving hydrophobic sulfur species on the surface. However, at higher potentials, iron species are replaced fast enough to depress its flotation. Effects of pH and polishing were also explored using EIS. Besides collectorless hydrophobicity, the activation of pyrrhotite with nickel ions and interaction with xanthate ions makes the separation more difficult. DETA and SO2 are commonly used as pyrrhotite depressants; however, the mechanism is not very well understood. Contact angle measurements, cyclic voltammetry and Tafel studies have been used to elucidate the depressing action of DETA and SO2. It was observed that DETA and SO2 complement each other in maintaining lower pulp potentials and removing polysulfides. DETA also helps in deactivating pyrrhotite. Therefore, the combined use of DETA and SO2 leads to the inhibition of both the collectorless flotation and the adsorption of xanthate. The adsorption of xanthate on sulfide minerals is a mixed-potential mechanism, i.e., the anodic oxidation of xanthate requires a cathodic counterpart. Normally, the cathodic reaction is provided by the reduction of oxygen. However, oxygen can be replaced by other oxidants. Ferric ions are normally present in the flotation pulp. Their source could be either iron from the grinding circuit or the ore itself. The galvanic studies were carried out to test the possibility of using ferric ions as oxidants and positive results were obtained. Tafel studies were carried out to measure the activation energies for the adsorption of ethylxanthate on several sulfide minerals. Pyrite, pyrrhotite (pure and nickel activated), chalcocite and covellite were studied in 10-4 M ethylxanthate solution at pH 6.8 at temperatures in the range of 22 – 30 0C. The Tafel studies showed that xanthate adsorbs as dixanthogen (X2) on pyrite and pyrrhotite, nickel dixanthate (NiX2) on nickel-activated pyrrhotite and cuprous xanthate (CuX) on both chalcocite and covellite. However, the mechanism for xanthate adsorption on each mineral is different. The free energy of reaction estimated from the activation energies are in good agreement with thermodynamically calculated ones.

FUNDAMENTO: evaluar el impacto a corto plazo de la contaminación atmosférica sobre la mortalidad diaria de la ciudad de Pamplona MÉTODO: Estudio ecológico con una población de 212.000 habitantes. Se realiza análisis de datos de series temporales, mediante regresión lineal múltiple y regresión de Poisson, con la información de datos de mortalidad diaria, niveles de contaminación atmosférica para Partículas y SO2, parámetros meterológicos de temperatura y humedad media diarios y número de casos semanales de gripe, en los años 1991 a 1995 RESULTADOS: La media de muertes diarias por causas no externas es de 4,15 muertos con un rango de cero a 13 muertes. La ciudad de Pamplona tiene una temperatura media anual de 12,7ºC (-2,3ºC a 31.6ºC) y una humedad relativa del 68.5%. En el modelo, la temperatura (con retardo de un día y retardo de 6 días temperatura al cuadrado) y la humedad (con retardo de un día) esta relacionada con la mortalidad por todas las causas. Pero la mortalidad por causas no externas sólo se relaciona en el modelo con la temperatura (retardo un día, P: 0.035) y cinco días con temperatura al cuadrado (p: 0.028) Las estimaciones puntuales del riesgo relativo de partículas muestran que el máximo riesgo de morir se produce en las causas respiratorias con un riesgo relativo de 1.13. Sin embargo ninguna de estas asociaciones es estadísticamente significativa. En el caso de Dióxido de Azufre las estimaciones están muy próximas al valor nulo y ninguna de ellas es significativa. CONCLUSIONES: la Temperatura tiene efecto sobre la mortalidad por todas las causas tanto externas como no externas y la humedad solo tienen efecto sobre la mortalidad por causas no externas. No se ha podido demostrar una influencia de los niveles diarios de contaminación ambiental sobre la mortalidad diaria.