Traditional aerosol samplers are limited in their abilities to collect large quantities of particulate matter due to their low flow rates, high pressure drops, and are noise intrusiveness. The goal of this study was to develop an alternate aerosol sampler using electrostatic precipitation technology that was safe and not noise intrusive to be deployed in homes. The O-Ion B-1000 was selected as the most suitable electrostatic precipitator (ESP) for achieving the goal of this study because of its affordability, the design of its collection electrode and its high flow rate. The collection efficiency of the ESP was assessed for three aerosols; Arizona Road Dust (ARD), NaCl and diesel fumes. ARD was found to have the highest average collection efficiency (65%) followed by NaCl (43%) and lastly diesel fumes (41%). A method for recovering the particulate matter deposited on the collection electrode was developed. The dust collected on the electrode was recovered onto polyvinyl chloride (PVC) filters moistened with deionized water. Additionally, the recovery of the three test aerosols, ARD, NaCl, and diesel fumes, from the collection electrode was assessed. A gravimetric analysis was done to determine the amount of dust recovered. The collection efficiency was used to calculate the amount of mass expected on the filter for a particular aerosol. NaCl had the highest recovery at 95% recovery, followed by ARD (73%) and lastly diesel fumes (50%). Two identical ESPs were also deployed in an office and in a bedroom, 104.47 mg and 9.64 mg of particulate matter (PM) was recovered respectively. The noise and ozone level produced by the ESP was evaluated to determine the ESP’s viability as a household aerosol sampler. The ESP’s high setting had a noise level of 45.8 dB and ozone generation rate of 0.036 mg/min. The results of the calculation showed that in an averaged size unventilated room (6.10 m × 6.10 m × 2.44 m), it would take 6 hours and 53 minutes for the ozone levels to reach the recommended maximum exposure limits per National Ambient Air Quality Standards (NAAQS). Additionally, a ventilation of 230 L/min is needed in order to prevent the ozone levels generated by the ESP from exceeding maximum exposure limits per NAAQS. Overall, the O-Ion B-1000 met the criteria of collecting 1 mg of PM in a 24 hour sampling for ARD and NaCl. Diesel fumes however, required 30 hours to collect 1 mg of PM. The noise levels generated by the ESP set on high was one dB above the Environmental Protection Agency (EPA) standards for indoor noise limit. However, the noise is proportional to inverse distance squared; the ESP should not pose a problem during household deployment. Ozone generated by the ESP was also found to be below 0.07 ppm as set by the EPA with an average ventilation of 230 L/min. The average ventilation of a household is 1500 L/min, thus the ozone generated by the ESP would not surpass 0.07 ppm. However, the ESP should not be deployed in unventilated rooms for a period of more than 6 hours and 53 minutes.

Chapter II describes results from 197 rural households that were sampled over five continuous days for indoor and outdoor PM10, PM2.5, and endotoxin. Geometric mean indoor concentrations of PM10 and PM2.5 (21.2 πg m-3, 12.2 πg m-3) were larger than outdoor concentrations (19.6 πg m-3, 8.2 πg m-3; p =0.072, p<0.001). While geometric mean endotoxin levels were almost six times larger in outdoor air compared to indoor (1.47 EU m-3, 0.23 EU m-3; p <0.001). Airborne PM10 and endotoxin concentrations in a rural county were elevated compared to those previously reported in certain urban areas. Furthermore, during the harvest season, concentrations of endotoxin in ambient air approached levels that have been shown to cause decreased respiratory function in occupational workers. Chapter III evaluated the effectiveness of using Radiello passive monitors to measure hydrogen sulfide (H2S) in close proximity (<40 m) to a medium sized CAFO. A total of eight passive H2S monitors were deployed 7-14 days around a swine confinement for seven months. Additionally, a separate laboratory study was carried out to determine the monitor's H2S uptake rate. Concentrations of H2S measured near the confinement were varied and ranged from 0.6 to 95 ppb depending on the sampling period and proximity to the lagoon .The uptake rate provided by the supplier (0.096 ng ppb-1 min-1) was significantly larger (p=0.002) than the rate determined experimentally (0.062 ng ppb-1 min-1). In Chapter IV we evaluated the association between residential proximity to swine operations and childhood asthma. A metric was created to determine children's relative environmental exposure to swine CAFOs which incorporated facility size and distance and direction of the CAFO to the home. When controlling for six significant asthma risk factors, children with a larger relative environmental exposure to CAFOs had a significantly increased risk of physician-diagnosed asthma (OR=1.20, p=0.009). In stratified analysis that adjusted for a respiratory infection before the age of two years, the association between relative exposure and childhood asthma was significantly increased in children with a respiratory infection (OR=1.45, p=0.001) but not in children free from respiratory infection (OR=1.12, p=0.355).

Particulate matter expelled from tunnel-ventilated animal feeding operations (AFOs) is known to transport malodorous compounds. As a mitigation strategy, vegetative environmental buffers (VEBs) are often installed surrounding AFOs in order to capture particulates and induce lofting and dispersion. Many farmers are or are interested in implementing VEBs, yet research supporting their efficacy remains sparse. Currently, point measurements, often combined with models, are the primary means by which emission rates from AFOs and VEB performance has been investigated. The existing techniques lack spatial resolution and fail to assign the observed particulate reduction to capture, lofting, or dispersion. In recent years, lidar has emerged as a suitable partner to point measurements in agricultural research. Lidar is regarded for its ability to capture entire plume extents in near real time. Here, a technique is presented for estimating the capture efficiency of a VEB using lidar. An experiment was conducted in which dust was released upwind of a VEB at a known rate, and the emission rate downwind of the VEB was estimated using an elastic scanning lidar. Instantaneous lidar scans showed periodic lofting well above the VEB, but when scans were averaged over several hours, the plumes appeared Gaussian. The experiment revealed a capture efficiency ranging from 21-74β, depending on the time of day. The methodology presented herein addresses deficiencies in the existing techniques discussed above, and the results presented add to the lacking body of research documenting VEB capture efficiency.

Particulate air pollution is known to exacerbate respiratory diseases, such as asthma and chronic obstructive pulmonary disease, in humans. It has been proposed that transition meta ls from inhaled particles may play a role in this exacerbation by generating radical species leading to damage in the lungs. The aim of this research was to determine the role that iron from particulate air pollution played in the generation of reactive oxygen species and subsequently the induction of inflammatory mediators in cells in culture. The production of reactive oxygen species by particulate air pollution was found to be dependent on the mobilization of iron from the particles by chelators, such as the physiologically relevant citrate. The amount of iron mobilized from the combustion particulate, coal fly ash, was dependent on the type of coal used to generate the fly ash and was greatest in the smallest size fraction collected for three different coal types. In addition, the amount of iron mobilized from coal fly ash by citrate correlated closely with the amount mobilized in human lung epithelial (A549) cells, as indicated by induction of the iron storage protein, ferritin. The amount of the proinflammatory cytokine, interleukin-8, secreted in response to coal fly ash treatment varied with the amount of iron mobilized intracellularly from the particles, with the greatest response to the smaller size fractions which released the largest amounts of iron. There was a direct relationship, above a threshold level of bioavailable iron, between the level of interleukin-8 and bioavailable iron in cells treated with coal fly ash. Tetramethyl thiourea and dimethyl sulfoxide prevented the increased production of interleukin-8 by human lung epithelial cells treated with coal fly ash, suggesting the role of a radical species in the induction of this inflammatory mediator. The mobilization of iron from coal fly ash by citrate or in human lung epihelial cells, as well as the induction of interleukin-8, did not correlate with the total amount of iron in the particles. Instead, preliminary results suggest that these measured values vary directly with the amount of iron contained in the aluminosilicate fraction of the fly ash.

Karenia brevis is a toxic marine dinoflagellate species that blooms almost every year in the Gulf of Mexico. These blooms have had devastating effects on local economies, as well as on the fauna of the area. The ECOHAB:Florida project was founded to study the population dynamics and trophic impacts of K. brevis. The project included a series of monthly hydrographic offshore research cruises, as well as monthly surveys of a transect along the 10-meter isobath of the West Florida Shelf. This study focused on data from the alongshore transect over a three-year period (1999-2001). Physical parameters (temperature, salinity, and density) and chemical parameters (particulate carbon, nitrogen, and phosphorus; dissolved inorganic nitrogen and phosphorus) of the West Florida Shelf were analyzed. The amount of chlorophll a and the location and amount of K. brevis cells present were also examined. Clear spatial, seasonal, and interannual patterns in the hydrographic parameters, particulate matter (C, N, P), dissolved inorganic nutrient (nitrite, nitrate, and phosphate), and chlorophyll a concentrations were found. At various times throughout the study, the location of K. brevis blooms was influenced by all of these factors except for the amount of dissolved inorganic nutrients. There were differences in particulate matter ratios present in bloom and non-bloom periods. No clear-cut differences in dissolved inorganic nutrients between bloom and non-bloom periods were found. Finally, relationships between the biological indicators of blooms (i.e., chlorophyll a) and the aforementioned physical and chemical parameters were found.

This thesis examines the particle capture, fibre wetting and droplet flow processes within wet filters collecting solid and liquid aerosols and within filters collecting only liquid aerosols. The processes involved in this type of filtration were examined through a series of experiments and models developed to describe the behaviour of fibre/liquid systems. This work can be summarized in 4 categories: (1) The bounce and immediate re-entrainment of liquid and solid monodisperse aerosols under a stable filtration regime (pre cake formation) by wet and dry fibrous filters. In this work it was found that the solid particles generally exhibited a lower fractional filtration efficiency than liquid particles (of the same size), although this difference decreased in the smaller size fractions. However, for the wet filtration regime (each fibre of the filter was coated by a film of water), no significant difference in filtration efficiency was detectable between solid and liquid aerosols. Either the bounce effect of the particles is inhibited by the liquid film, or the filtration conditions in the wet filter are so different that the aerosol properties are less significant with respect to capture. (2) A microscopic study of the effect of fibre orientation on the fibre wetting process and flow of liquid droplets along filter fibres when subjected to airflow and gravity forces was conducted. The flow of the liquid collected by the fibres was observed and measured using a specially developed micro-cell, detailed in the thesis. The experimental results were compared to a theoretical model developed to describe the flow of droplets on fibres. The theory and experimental results showed a good agreement. A sensitivity analysis of the model was performed which showed the droplet radius to be the most significant parameter. The model has the potential to improve filter self-cleaning and minimise water use. (3) An experimental study of the capture of solid and liquid (oil) aerosols on fibrous filters wetted with water. Variable quantities of liquid irrigation were used, and the possibility for subsequent fibre regeneration after clogging or drying was also studied. It was found that self-cleaning (removal of solid aerosols by water) occurred even under heavily dust-laden conditions, and post evaporation of water. With the collection of oil aerosols on fibres wetted with water, a predominance of the barrel shaped droplet on the fibre was observed, with oil droplets displacing water droplets (if the oil and fibre combination created a barrel shaped droplet), creating various compound droplets of oil and water not previously reported in literature. (4) An extensive experimental investigation of the wetting processes of fibre/liquid systems during air filtration (when drag and gravitational forces are acting) has shown many important features, including droplet extension, oscillatory motion, and detachment from fibres as airflow velocity increases. The droplet oscillation is believed to be induced by the onset of the transition from laminar to turbulent flow as droplet size increases. To model such oscillation it was necessary to create a new conceptual model to account for the forces both inducing and preventing such oscillation. The agreement between the model and experimental results is satisfactory for both the radial and transverse oscillations.

The EPA press release dated February 23, 2004 states that the three Buckeye Egg Farm facilities had the potential to emit more than a combined total of 1850 tons per year of particulate matter (PM). This number was based on flowrate calculations that were three times higher than those measured as well as a failure to include particle size distributions in the emissions calculations. The annual PM emission for each facility was approximately 35 tons per year. The EPA was unjustified in requiring Buckeye Egg Farm to obtain Title V and PSD permits as the facilities could not have met the thresholds for these permits. Engineers need to be concerned with correctly measuring and calculating emission rates in order to enforce the current regulations. Consistency among regulators and regulations includes using the correct emission factors for regulatory permitting purposes. EPA has adopted AERMOD as the preferred dispersion model for regulatory use on the premise that it more accurately models the dispersion of pollutants near the surface of the Earth than ISCST3; therefore, it is inappropriate to use the same emission factor in both ISCST3 and AERMOD in an effort to equitably regulate PM sources. For cattle feedlots in Texas, the ISCST3 emission factor is 7 kg/1000 hd-day (16 lb/1000 hd-day) while the AERMOD emission factor is 5 kg/1000 hd-day (11 lb/1000 he-day). The EPA is considering implementing a crustal exclusion for the PM emitted by agricultural sources. Over the next five years, it will be critical to determine a definition of crustal particulate matter that researchers and regulators can agree upon. It will also be necessary to develop a standard procedure to determine the crustal mass fraction of particulate matter downwind from a source to use in the regulatory process. It is important to develop a procedure to determine the particulate matter mass fraction of crustal downwind from a source before the crustal exclusion can be implemented to ensure that the exclusion is being used correctly and consistently among all regulators. According to my findings, the mass fraction of crustal from cattle feedlot PM emissions in the Texas High Plains region is 52%.

This thesis is focused upon chemistry as a school subject and students' interpretations and use of formally introduced teaching models. To explore students' developing repertoire of chemical models, a longitudinal interview study was undertaken spanning the first year of upper secondary school chemistry. Matter in its different states was selected as the target framework for this study. The results presented are derived from both generalisations of groups of students as well as a case study describing an individual learner's interpretation of formal content. The results obtained demonstrated that the formal teaching models provided to the students included in this study were not sufficient to afford them a coherent framework of matter in its different states or for chemical bonding. Instead, students' expressed models of matter and phase change were to a high degree dependent on electron movement (Paper I), anthropomorphism (Paper II) and, for one student, a mechanistic approach based on small particles and gravitation (Paper III). The results from this study place focus on the importance of learners' prior learning (previous experiences) and the need to develop a coherent framework of formal teaching models for the nature of matter and phase change.

This study introduces a multiscale model for analyzing nonlinear thermo-viscoelastic responses of particulate composites. A simplified micromechanical model consisting of four sub-cells, i.e., one particle and three matrix sub-cells is formulated to obtain the effective thermal and mechanical properties and time-dependent response of the composites. The particle and matrix constituents are made of isotropic homogeneous viscoelastic bodies undergoing small deformation gradients. Perfect bonds are assumed along the sub-cell⁰́₉s interfaces. The coupling between the thermal and mechanical response is attributed to the dissipation of energy due to the viscoelastic deformation and temperature dependent material parameters in the viscoelastic constitutive model. The micromechanical relations are formulated in terms of incremental average field quantities, i.e., stress, strain, heat flux and temperature gradient, in the sub-cells. The effective mechanical properties and coefficient of thermal expansion are derived by satisfying displacement- and traction continuities at the interfaces during the thermo-viscoelastic deformations. The effective thermal conductivity is formulated by imposing heat flux- and temperature continuities at the subcells⁰́₉ interfaces. The expression of the effective specific heat at a constant stress is also established. A time integration algorithm for simultaneously solving the equations that govern heat conduction and thermoviscoelastic deformations of isotropic materials is developed. The algorithm is then incorporated within each sub-cell of the micromechanical model together with the macroscopic energy equation to determine the effective coupled thermoviscoelastic response of the particulate composite. The numerical formulation is implemented within the ABAQUS, general purpose displacement based FE software, allowing for analyzing coupled heat conduction and deformations of composite structures. Experimental data on the effective thermal properties and time dependent responses of particulate composites available in the literature are used to verify the micromechanical model formulation. The multiscale model capability is also examined by comparing the field variables, i.e., temperature, displacement, stresses and strains, obtained from heterogeneous and homogeneous composite structures, during the transient heat conduction and deformations. Examples of coupled thermoviscoelastic analyses of particulate composites and functionally graded structures are also presented. The present micromechanical modeling approach is found to be computationally efficient and shows good agreement with experiments in predicting the effective thermo-mechanical response of particulate composites and functionally graded materials. Our analyses forecast a better design for creep resistant and less dissipative structures using particulate composites and functionally graded materials.

Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Models successfully reproduce the concentrations of gas phase and PM phase species. Vehicles, natural gas, industries, and coal combustion are important O3 sources. Upwind sources have non-negligible influences (20-50%) on daytime O3, indicating that regional NOx emission controls are necessary to reduce O3 in Southeast Texas. EC is mainly from diesel engines while majority of primary OC is from internal combustion engines and industrial sources. Open burning, road dust, internal combustion engines and industries are the major sources of primary PM2.5. Wildfire dominates primary PM near fire locations. Over 80% of sulfate is produced in upwind areas and coal combustion contributes most. Ammonium ion is mainly from agriculture sources. The SOA peak values can be better predicted when the emissions are adjusted by a factor of 2. 20% of the total SOA is due to anthropogenic sources. Solvent and gasoline engines are the major sources. Oligomers from biogenic SOA account for 30-58% of the total SOA, indicating that long range transport is important. PAHs from anthropogenic sources can produce 4% of total anthropogenic SOA. Wild fire, vehicles, solvent and industries are the major sources. EC and OC emitted within 0-3 hours contribute approximately 70-90% in urban Houston and about 20-40% in rural areas. Significant diurnal variations in the relative contributions to EC are predicted. Fresh particles concentrations are high at morning and early evening. The concentrations of EC and OC that spend more than 9 hours in the air are low over land but almost accounts for 100% of the total EC and OC over the ocean.