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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Spatial Distribution of Nitrogen Oxides, Benzene, Toluene, Ethylbenzene, and Xylenes in Hillsborough County, Florida: An Investigation of Impacts of Urban Forests on Ambient Concentrations of Air Pollutants Associated with Traffic

Sears, Jill 01 January 2013 (has links)
Urban air pollution is responsible for high levels of morbidity and mortality in exposed populations due to its effects on cardiovascular and respiratory function. Transportation-related air pollutants account for the majority of harmful air pollution in urban areas. Forests are known to reduce air pollution through their ability to facilitate dry deposition and atmospheric gas exchange. This work characterizes the interactions between transportation air pollutants and urban forests in Hillsborough County, Florida. A highly spatially resolved passive air sampling campaign was conducted to characterize local concentrations of nitrogen oxides, benzene, toluene, ethylbenzene, and xylenes (BTEX) in Hillsborough County, Florida. Sampling locations included a proportion of densely forested urban areas in order to determine the effects of Hillsborough County's urban forest resources on localized concentrations of selected transportation pollutants. Recommended approaches for the use of urban forests as an effective air pollution mitigation technique in Hillsborough County were generated based on results from the sampling campaign. Results show mean concentrations of 2.1 parts per billion and 6.5 µg/m3 for nitrogen oxides and total BTEX, respectively. High spatial variability in pollutant concentrations across Hillsborough County was observed, with the coefficient of variation found to be 0.61 for nitrogen oxides and 0.79 for total BTEX. Higher concentrations were observed along interstate highways, in urban areas of the county, and near select point sources in rural areas. Differences in concentrations within forested areas were observed, but were not statistically significant at the 95%#37; confidence level. These results can be used to identify elements of urban design which contribute to differences in concentrations and exposures. This information can be used to create more sustainable urban designs which promote health and equity of the population.
92

Assessment of Public Health Risks Associated with Petrochemical Emissions Surrounding an Oil Refinery

Pulster, Erin L. 01 January 2015 (has links)
Refinery operations have been associated with a wide variety of atmospheric emissions consisting of criteria air pollutants, volatile organic components, hazardous air pollutants as well as other pollutants. With approximately 100 oil refineries in the Wider Caribbean region (WCR), hydrocarbons in this region pose significant environmental and human health risks. One of the oldest and largest refineries in the WCR is the Isla Refineriá, which is located on the island of Curaçao, and has been the basis of historical debates and conflict between the public and the local government over the environmental and human health risks. This research aims to establish baseline levels of ambient petrochemical emissions in Curaçao, specifically polycyclic aromatic hydrocarbons (PAHs), inhalable particulate matter (PM10) and sulfur dioxide (SO2), and to evaluate through comparative literature analysis and recommended public health guidelines the potential health risks in Curaçao. In addition, source elucidation of PAHs was conducted using concentration profiles, distribution profiles, binary diagnostic ratios and factor analysis. Passive air samplers with polyurethane foam collection disks (PAS-PUFs) were deployed in 2011 (n=43) and in 2014 (n=30) to measure ambient PAH concentrations. Ambient PAH concentrations ranged from 1.2 ng/m3 in 2011 and 27.3 to 660.1 ng/m3 in 2014, demonstrating no temporal differences. However, there were highly significant spatial differences, with the samples downwind of the refinery having significantly higher ambient PAH concentrations than those upwind in 2014. Source elucidation revealed the ambient PAHs were dominated by petrogenic emission sources (i.e., refinery) in the 2011 and the 2014 downwind samples, whereas the 2014 upwind locations were equally influenced by both petrogenic (i.e., refinery) and pyrogenic (i.e., vehicle emissions) sources. Available hourly, daily and monthly PM10 and SO2 measurements were downloaded from June 2010 through December 2014 from two local air monitoring stations. Concentrations of both PM10 and SO2 in Curaçao are among the highest reported globally, demonstrating an increasing trend over time and exceed current public health guidelines recommended by local and international agencies. It is plausible that the residents of Curaçao may experience health effects often associated with PM10 and SO2, however the epidemiological evidence is inadequate to infer causality between health effects and long-term exposures. Using the USEPA’s risk analysis methodology the resulting cumulative lifetime cancer risk estimates from PAH inhalation were below the level of concern (1.0 x 10-4). In contrast, by evaluating the potency adjusted concentrations relative to the most toxic compound (benzo[a]pyrene), age class (children and adults) extrapolated and site specific risks indicated levels exceeding the upper bound acceptable risk (1.0 x 10-4) by almost two orders of magnitude suggesting the need for remediation.
93

Subsidies, Agriculture, & Climate Change

McNamara, Kevin 01 January 2015 (has links)
This paper looks at the impact of agricultural subsidies on beef production in the fifty states of America, due to the adverse effects that large-scale agriculture production has on the Earth's climate. I examine production, sales, and employment data from the 2012 and 2007 USDA Agriculture Census to examine if there is or isn't a link between these factors and the level of beef subsidies received by each state.
94

Effectiveness of Biocide Substitution and Management Plan Implementation for the Control of

Bones, Adelmarie 05 March 2018 (has links)
After the notorious outbreak and discovery of Legionella bacteria in 1976, the waterborne pathogen was added to the list of disease-causing agents associated with the built environment. Legionella pneumophila was discovered when it was identified as the agent that caused 34 deaths and an outbreak of pneumonia-like symptoms in several attendees of the 1976 American Legion Convention held in Philadelphia (OSHA, 2017). Recently published data from the year 2015 reported more than 6,000 Legionnaires’ cases identified in the United States (CDC, 2016). This is a concerning number given that one in every ten infected persons will die of the disease. It is believed that case numbers are likely under-reported, given that Legionnaires’ disease is very difficult to diagnose. Legionella species live naturally in bodies of water, including lakes and rivers. Legionnaires’ disease has been associated with the introduction of Legionella into manmade water systems. The presence of Legionella has been reported in cooling towers, domestic hot-water systems, humidifiers, decorative fountains, grocery spray misters, spas, whirlpools, and dental water lines, among other systems housing stagnant water (CDC, OSHA, 2017). From an occupational exposure standpoint, cooling towers are considered the most concerning source of Legionella pneumophila exposures, based on data from previous cases (Principe et al., 2017). The purpose of this research was to measure the effectiveness of biocide substitution and maintenance management in evaporative condensers. Such condensers were previously identified as having high counts of Legionella pneumophila in the water and/or on surfaces. The study sites were in the states of Florida and Georgia. Initial water testing for Legionella was carried out between July and August of 2016. Results from 2016 showed high counts of colony forming units (CFU) per millimeter (mL) at baseline assessment. An intervention of biocide substitution and enhanced management planning was recommended to lower or eliminate L. pneumophila from the water basins of the evaporative condensers. Follow-up results of water sampling conducted between July and August 2017 showed reduction of CFU counts after the intervention plan had been implemented for an entire year.
95

A Study on the Effect of Non – Asthmatic Atopy on Pregnancy Outcomes

Johnson, Ayesha 24 March 2016 (has links)
Objectives – To measure the effect of non – asthmatic atopy (NAA) on the risk of adverse pregnancy outcomes; low birth weight (LBW), small for gestational age (SGA) and preterm birth (PTB), among primiparous women 19 – 25 years of age. Methods – Vital Statistics records from births occurring between 2004 and 2014, from approximately 60,000 primiparous women in South Carolina, aged 19 to 25 years, were linked to their Medicaid records. Maternal records were examined to determine if they had a previous diagnosis of NAA. Women with a diagnosis of NAA were frequency matched with a ratio of 1:4 to non – atopic controls by age, sex of infant, and asthma diagnosis. Next, the frequencies of LBW, SGA and PTB were compared across the two groups of women. Tests for linear trend across birth weight categories and gestational age at birth categories were then conducted after which separate Poisson regression models were estimated to measure the risk of each outcome. Results – Linear tests for increasing trend were statistically significant (p < 0.001); indicating that higher percentages of NAA are associated with higher infant birth weight. Similarly, higher percentages of NAA were associated with greater gestational age at birth. After controlling for maternal race/ethnicity, smoking during pregnancy, gestational diabetes and pre – pregnancy hypertension; mothers with a diagnosis of NAA had reduced risk for each outcome (RR = 0.96, 0.94 and 0.95 for LBW, SGA and PTB respectively). These results were not statistically significant (p > 0.05). Similar results were seen when data was further explored by maternal race/ethnicity. Conclusions – NAA could promote a healthy pregnancy and reduce the risk of adverse outcomes and should therefore be taken into account when assessing a woman’s risk of same. Until now this protection has gone unnoticed due to the increase in the risk of study outcomes that are associated with a diagnosis of asthma, and the fact that in many instances asthma is present with NAA. Additional analyses are needed to evaluate unknown factors associated with its diagnosis and treatment. Keywords: rhinitis, dermatitis, asthma, low birth weight, small for gestation age, preterm birth, race/ethnicity
96

Predicting Hand Surface Area from a Two-Dimensional Hand Tracing

O'Mara, Myles 03 November 2017 (has links)
Recent occupational health studies have focused on dermal exposure at the hands, but have been unable to accurately express dose without knowing the HSA. There is no standard method to calculate HSA, though some researchers have derived HSA formulas based on dimensions from a Taiwanese population. This research paper describes a shortcut method to estimate the hand surface area (HSA) of a human hand from a two-dimensional hand tracing, and repeated a Taiwanese HSA study in order to explore the viability of its HSA formula in an American university population. A sample of nine adult men and nine adult women, each representing one third of the population percentile in hand length and hand breadth, were selected from a population within the University of South Florida in Tampa, FL. Hand length, breadth, a 2D hand tracing and a 3D light hand scan were collected from each participant. A linear regression was used to analyze the data sets and found a correlation (R=0.94) between 2D HSA and 3D HSA and slope of 2.6 (SD=0.2), with a regression equation of Y=2.6(X). A paired t-test was used to compare the Taiwanese HSA formula data against the 3D HSA. Results found that the Taiwanese data sets were significantly different from the 3D HSA (p<0.001), averaging 57 cm2 less than the 3D HSA. A jackknife analysis was implemented on the 2D HSA hand tracing data, and a paired t-test was performed between the jackknife estimate predictions and 3D HSA. Mean differences were not significantly different (p=0.97), with 0.87 cm2 difference between means. Results indicate that the USF Hand Tracing Method will provide a better estimate of HSA than the Taiwanese method, and can be used as a tool in HSA estimation.
97

Influence of Environmental Parameters on Mold Sampling Results

Fishman, Benjamin 16 June 2017 (has links)
Mold is a type of fungus present in nearly all environments. Mold thrives under several environmental parameters such as high humidity and an adequate food source. A professional, such as an industrial hygienist, can measure mold in indoor and outdoor environments. Industrial hygienists commonly use a cascade impactor with a culture plate to capture air within a sampling area. While collecting air samples, environmental parameters such as temperature, humidity, and carbon dioxide are recorded. A laboratory then cultures and analyzes the samples, identifying the types and amounts of viable mold found in the sampling area. In this study, a data analysis method is used to interpret lab results and compare those results to the environmental parameters measured during collection. The study aims to show the relationship between the environmental parameters (temperature, humidity, carbon dioxide) and the types and amounts of mold that were measured in both indoor built environments and their surrounding outdoor areas. Among all 170 different sampling locations, the outdoor areas had higher counts and concentrations of mold. In addition, both indoor and outdoor areas saw Penicillium, Aspergillus, and Cladosporium as the most prevalent molds, with Cladosporium having the highest counts. Lower temperatures and humidity had a very small influence on mold growth and thus, yielded the lowest counts. Furthermore, the highest concentrations of mold were found within the same temperature and humidity ranges for both indoor and outdoor environments.
98

Effects of Temperature on the Emission Rate of Formaldehyde from Medium Density Fiberboard in a Controlled Chamber

Swankie, William 14 June 2017 (has links)
Formaldehyde is a colorless gas that is found naturally in the environment. It is a popular additive in many consumer products including composite wood products. Composite wood products are engineered wood panels produced from pressing pieces, chips, particles, or fibers of wood together at high temperatures held together with a bonding agent. This bonding agent is often formaldehyde-containing resins that are known to release formaldehyde over time. This is concerning because of the carcinogenic classification of formaldehyde, the wide spread application of composite wood products, and the increasing amount of time spent in the indoor environment. In a controlled 0.53 m3 chamber, a panel of medium density fiberboard (MDF) with a surface area of 4.49 m2 was subjected to multiple temperatures to measure formaldehyde emissions. The panels were allowed to acclimate for 48 hours followed by a 72 hour sample period using passive diffusive monitors at temperatures: 26.1, 29.3, 34.1, and 38.9 °C. The results of the study found a strong relationship (R2 = 0.9954) between the emission rate of formaldehyde from MDF and temperature. The emission rate increased 192% between 26.1 °C and 38.9 °C. The results of the study indicate that as temperature increases, the amount of formaldehyde emitted from a panel of MDF also increases. This results in higher airborne concentrations of formaldehyde in environments where the panels are present.
99

Evaluation of Pulmonary Function among Workers Engaged in the Manufacture of Hydraulic Fracking Ceramic Proppant

Rahman, Humairat H. 06 April 2016 (has links)
Workers involved in hydraulic fracking processes are exposed to various types of chemicals and dusts in their workplaces, such as proppants, which hold open the fissures created in the fracking process. Recently, ceramic proppants have been developed that may be less hazardous to workers than traditional proppants. Pulmonary function testing of workers producing ceramic proppant was used to assess the potential inhalation hazards of ceramic proppant. Male workers (n = 100) from a producer of ceramic proppant were evaluated with pulmonary function test data collected and evaluated using The American Thoracic Society (ATS) acceptability criteria. A comparison group was selected from the Third National Health and Nutrition Examination Survey (NHANES III) spirometry laboratory subset. No pulmonary function deficits were found in the worker group in comparison to the NHANES III population. Multiple linear regression analysis showed that the mean FEV1 and FVC values in workers were 0.11 and 0.08 liters respectively, and were greater as compared to the NHANES III population. Curiously, an FEV1/FVC ratio of less than 0.8, when compared to the NHANES III group, produced an odds ratio of 0.44 in worker group, indicating less risk of preclinical pulmonary dysfunction. Overall, exposure to ceramic proppant was not found to produce an adverse impact on pulmonary function in workers engaged in the manufacture of ceramic proppant.
100

Human Health Risk Characterization of Petroleum Coke Calcining Facility Emissions

Singh, Davinderjit 05 April 2016 (has links)
Calcined coke is a high quality carbon material produced by calcining green petroleum coke. Calcining is the process of heating green petroleum coke in a kiln to remove excess moisture, extract all remaining hydrocarbons, and modify the crystalline structure of the coke into a denser, electrically conductive product. The final product, calcined coke, is primarily used to make carbon anodes for the aluminum industry and recarburizing agent for industries such as the steel industry. If not appropriately controlled, the calcining process could lead to excess production of particulate emissions from either handling or storing of raw coke, or from the stack emissions during the production of calcined coke. Though calcined coke has shown low hazard potential in human populations due to low volatile content, there remains some public health concern regarding the emissions from these facilities. This study is designed to evaluate the emissions of petroleum coke calcining facility and assess the public health concern from the processes engaged in the handling and storage of green coke as well as from the calcining process. The ambient air levels were measured from a calcining facility and compared with the standards promulgated by USEPA. The results showed that pollutant contribution from the facility, measured by monitoring carbon fraction of the emissions, was de-minimis. The current research also studied whether the exposure levels and health risks specified in various epidemiological studies correlate with the standards promulgated by USEPA to protect public health from petrochemical emissions.

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