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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.
21

Chemicals in consumer products: occupational exposure assessment, health impacts, and predictors of semi-volatile organic chemicals

Craig, Jessica Ann 26 September 2020 (has links)
The public comes into contact with numerous semi-volatile organic chemicals (SVOCs) on a daily basis, and there is a lack of knowledge about exposure and health effects associated with many SVOCs, particularly newer compounds. Our objective was to characterize occupational exposure to SVOCs in nail salon workers, analyze exposure to one class of SVOCs in pregnant women and their young children, and examine associations between prenatal exposure and birth outcomes. From 10 female nail salon workers in the Boston area (2016–2017), we compared phthalates, phthalate alternatives, and organophosphate esters (OPEs) or their metabolites measured in pre- and post-shift urine samples and silicone wrist bands (SWBs). From 134 mother infant pairs from the Newborn Epigenetics STudy (NEST), a North Carolina birth cohort (2009–2011), we used multivariable and weighted quantile sum (WQS) regression models to estimate associations between individual and mixtures of prenatal serum per- and polyfluoroalkyl substances (PFAS) concentrations. In a subsample of 84 NEST offspring aged 3–6 years enrolled in the Toddlers Exposure to SVOCs in Indoor Environments (TESIE) study (2014–2016), we estimated associations of child serum PFAS concentrations with environmental, behavioral, and demographic predictors. Among nail salon workers, post-shift urine concentrations were generally higher than pre-shift for SVOC metabolites. Correlations between metabolites in urine and SWBs suggested occupation as a source of exposure. The PFAS mixture index was negatively associated with gestational age at birth among all and male offspring with less evidence of an association among females or for other birth outcomes. Diet, drinking water, maternal serum PFAS concentrations during pregnancy, and air concentrations inside the home were predictors of certain child serum PFAS concentrations. Nail technicians are occupationally exposed to SVOCs, with evidence of SWBs as a useful exposure assessment tool for future studies. We observed negative associations between prenatal PFAS concentrations and gestational length; male offspring may be more susceptible than females. Eating habits, drinking water source, prenatal serum concentrations, and air concentrations inside the home were predictive of child serum PFAS concentrations. Our results suggest that exposure to SVOCs is multi-faceted and of potential public health concern.
22

The impact of aviation activities on ambient particle number concentration and incident hypertension

Kim, Chloe Seyoung 26 September 2020 (has links)
Aviation industry has played an essential role in modern society by providing social and economic benefits, but with inevitable environmental and public health implications. Communities living near airports are potentially affected by increased exposures to aviation-related emissions as well as noise. Better characterization of the impacts of aircraft emissions and noise is of great public health concern, especially for those living in communities near airports. The goal of my dissertation was to investigate the contribution of arrival aircraft to ambient ultrafine particulate matter (UFP) concentration as well as to examine the impact of aircraft noise on hypertension. Various aviation-related air pollutants have been studied, including UFP, due to the high emission rates from aircraft and potential adverse health effects. Multiple studies have concluded that aircraft arrivals contribute significantly to ambient UFP concentration over a broad geographic area, but few studies have had the necessary monitoring infrastructure to formally evaluate the magnitude and spatial extent of impact. Because of its small size and negligible mass, UFP has significant spatial and temporal variability, which warrants further investigation in order to better understand its dispersion patterns and impact in communities near airports. In our study, we collected UFP concentration data, measured as particle number concentration (PNC), at multiple locations near a major arrival flight path into Boston Logan International Airport, gathering concurrent flight activity and meteorological data for the purpose of source attribution. Two study aims were developed in order to better understand the arrival aircraft contribution to ambient PNC: 1) to investigate the spatiotemporal pattern of PNC concentrations across multiple study sites that are at varying distances from arrival aircraft flight paths, and 2) to quantify the PNC contribution from individual aircraft while explicitly accounting for meteorology, considering the implications of utilizing different averaging times and distributional characterizations (e.g., mean, 95th percentile). Results of the first aim of this study indicated that being downwind of the airport as well as the arrival flight path under higher wind speed was associated with elevated PNC. In addition, during hours of high flight activity, the aircraft contribution to ambient PNC was detectable even at a site 17 km away from the airport. The second aim of the study found a significant contribution of arrival aircraft to ambient PNC even when controlling for other important predictors in multivariable regression models. Our models also revealed that using the 95th percentile PNC within an hour led to larger estimates of arrival aircraft contributions than using the mean PNC, corresponding to strong and intermittent signal from aviation. Similar to UFP, aircraft noise also displays strong spatiotemporal variability and has been shown to be associated with an array of adverse health outcomes including sleep disturbance and increased blood pressure in exposed communities. Though there is accumulating evidence of the association between aircraft noise and hypertension, existing studies are not without limitations. In our study, we developed long-term time-varying aircraft noise estimates for 90 airports in the U.S. using a single noise model and assigned noise estimates based on geocoded addresses of participants in Nurses’ Health Studies (NHS and NHS II), two existing large prospective cohorts of women. The aim of this study was to examine the association between aircraft noise and incident hypertension in female nurses utilizing high temporal and spatial resolution aircraft noise exposure estimates in order to reduce potential exposure misclassification while accounting for temporality. Our study results showed an increased risk for incident hypertension associated with increased aircraft noise in both cohorts controlling for potential confounders. Our study also confirmed the impact of aircraft noise on hypertension apart from that of air pollution. In summary, we found that aircraft activity can contribute significantly to ambient PNC. We developed a spatiotemporal model of aircraft noise and found that it is significantly associated with increased risk for hypertension in a large prospective cohort study, independent of the effects of air pollution on hypertension. Together, our work reinforces the importance of quantifying the environmental and public health impacts of aviation activities and provide future directions for research.
23

Welding Fume Particle Emissions from Pulsed Gas Tungsten Arc Welding (GTAW-P)

Tipton, Logan January 2021 (has links)
No description available.
24

Proving Environmental Health Violations

Sikora, V. 01 January 1981 (has links)
No description available.
25

Effective Compliance Strategies

Sikora, V. A., Harrison, J. 01 January 1981 (has links)
No description available.
26

Lawful Inspections

Sikora, V. A. 01 January 1979 (has links)
The constitutional law surrounding health inspections seems clear; inspections may be conducted with consent, with a warrant, or if it falls within one of the few exceptions. Federal, state, and local environmental health personnel must comply with this constitutional mandate and any other appropriate more restrictive statutes. Non-compliance is fruitless and, for the individual sanitarian, may be financially disastrous.
27

Sensitivity to Oral Food Allergies in Subjects with Allergic Rhinitis and Eczema

Syck , Megan Paige 30 September 2021 (has links)
No description available.
28

Modeling the impact of building energy policies and warming temperatures on indoor environmental quality, energy, and occupant health

Connolly, Catherine Laura 26 August 2022 (has links)
Regional temperature variability across the United States contributes to differential building energy demand for heating and cooling as well as differential indoor environmental quality (IEQ). With increasing ambient temperatures from the effects of climate change, these patterns will evolve in the coming decades. Issues related to energy use and IEQ are particularly challenging in multi-zone buildings, such as multi-family homes and schools, which have different energy requirements and airflow properties compared to the better well-characterized single-family homes. The complexity is even greater given that these buildings are targets for energy efficiency measures as a climate mitigation strategy to reduce energy consumption and greenhouse gas emissions. Multi-zone buildings also have well-known ventilation issues and concerns about operating costs for schools and other large buildings. It is therefore a high priority to understand more about energy and IEQ in multi-family homes and schools, assessing the implications of a warming climate, addressing competing energy and IEQ interests, and providing sustainable and equitable solutions. This dissertation applies multiple novel modeling approaches to evaluate challenges related to IEQ, energy use, health, and climate change implications in multi-zone buildings. First, we evaluated indoor air quality (IAQ), energy use, and health in a multi-family home in six regional climate zones using building simulation and discrete event simulation models. We found that daily ambient-sourced PM2.5 decreased while cooking-sourced PM2.5 increased with higher ambient temperatures. We also concluded that air changes per hour due to infiltration were higher on the first compared to the fourth floor, especially in colder climates, and we quantified how much window opening decreased total PM2.5 and NO2 concentrations and asthma events while increasing energy demand. Next, we modeled the impact of future weather scenarios on a multi-family home in Boston, MA and evaluated the implications of two stylized policy levers (cooling subsidies and energy efficiency retrofits) across three different air conditioning utilization groups (no AC, some AC, and full AC). We found that cooling demand would increase for the AC groups but heating demand would decrease, leading to net reductions in total utility costs. Cooling subsidies allowed groups to remain thermally comfortable, but would increase household energy costs more than baseline due to increased AC utilization and associated cooling energy demand. Energy efficiency retrofits greatly reduced heating demand and slightly reduced cooling demand for groups already with AC use. Finally, we modeled the implications of combined ventilation upgrades and rooftop garden installation at a high school for total energy consumption and cost, indoor carbon dioxide (CO2) concentrations, and carbon emissions. We found that the overall benefits to heating and cooling outweighed the increase in energy for ventilation, with a substantial decrease in indoor CO2 and an overall reduction in carbon emissions. This dissertation provides insight regarding sustainable and health-promoting solutions for climate mitigation and adaptation for multi-zone buildings. / 2024-08-26T00:00:00Z
29

Chronic kidney disease of unknown etiology in Nicaragua: investigating the role of environmental and occupational exposures

Laws, Rebecca L. 03 October 2015 (has links)
Background: In Central America, an epidemic of chronic kidney disease (CKD) primarily affects younger, male agricultural workers. Hypothesized causal agents include heat stress, agrichemicals, and heavy metals, among others, but the etiology remains unknown. Our aims were to assess job-specific changes in kidney function and injury during the sugarcane harvest season, characterize hydration practices and metals exposure, and determine whether these agents are associated with kidney function and injury. The overall goal was to address this public health emergency to inform intervention and prevention strategies. Methods: We recruited 284 sugarcane workers, representing seven job tasks, and 51 miners, all from northwestern Nicaragua. We sampled sugarcane workers at two time points (before and near the end of the harvest season) and miners at one time point. As a marker of kidney function, we measured serum creatinine to estimate glomerular filtration rate (eGFR). As markers of kidney injury, we measured urinary neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), N-acetyl-D-glucosaminidase (NAG), albumin, and creatinine. We measured blood lead and urinary cadmium, uranium, and total arsenic in a subset of sugarcane workers and miners. Results: Kidney function (eGFR) declined during the harvest season in seed cutters, irrigators, and cane cutters compared to other jobs, and kidney injury biomarkers (NGAL, IL-18) increased during the harvest, most notably among cane cutters. Electrolyte solution consumption appeared protective in cane cutters, a job with high heat exposure and heavy manual exertion. Though metal biomarkers were not elevated, there was some evidence that combined exposure to multiple metals was associated with decreased kidney function and increased injury. Albuminuria was rare. Conclusions: These findings provide evidence that occupational exposures are involved in the etiology of CKD. Heat stress and volume depletion may play a role, most likely in combination with one or more other agents, possibly environmental exposure to low-level metals. Our results do not support the hypothesis that agrichemicals are causal, but future studies that quantify exposure to specific agents are needed. The limited albuminuria and presence of tubular injury markers supports a tubulointerstitial disease that could occur with repeated subclinical injury leading to clinically apparent CKD over time.
30

Metal mixtures and the role of iron status in early adolescent cognition

Schildroth, Samantha 26 April 2023 (has links)
Children are commonly exposed to metals in the environment, particularly those living in proximity to steel-producing ferroalloy industry. Exposure to metals, including lead (Pb), manganese (Mn), chromium (Cr) and copper (Cu), impacts neurodevelopment, but less attention has been given to examining associations of metal mixtures with cognitive function in children. Further, recent epidemiological studies have identified iron (Fe) status as a modifier of metals-induced neurotoxicity, such that adverse associations of metals (e.g., Mn or Pb) tend to be stronger among children with Fe deficiency. However, no study to date has quantified the modifying or mediating role of Fe status on a complex metal mixture in relation to any neurodevelopmental outcome. We used data from the Public Health Impact of Metals Exposure Study (PHIME), a cohort of 720 Italian adolescents (10–14 years) to quantify the association of an industry-relevant metal mixture (Pb, Mn, Cr, Cu) with neurodevelopment, and examine the role of Fe status as a modifier or mediator of these associations. Metals were measured in blood (Pb) or hair (Mn, Cr, Cu) using inductively-coupled plasma mass spectrometry, and Fe status was assessed using three clinically relevant biomarkers (ferritin, hemoglobin, transferrin) measured in whole blood or serum using luminescent or immunoassays. Of note, there was no indication of Fe deficiency in the study population. In Chapter 2, we identified associations of the metal mixture with verbal learning and memory, measured using the California Verbal Learning Test for Children (CVLT-C), using Bayesian Kernel Machine Regression (BKMR). In adjusted models, we found that the mixture was jointly associated with higher scores for the recall trials: compared to the 50th percentile, the 90th percentile of the mixture was associated with a 0.12 standard deviation increase (95% credible interval [CI]= -0.27, 0.50) in the number of words recalled on trial 5 recall, indicating better cognitive performance. This association was driven primarily by Cu, which was further modified by Fe status: the beneficial association of Cu with recall was stronger at increasing percentiles of ferritin. In Chapter 3, we found that the metal mixture was jointly associated with self-reported attention-related behaviors measured on the Conners Rating Scales. For example, the 90th percentile of the mixture, compared to the 50th percentile, was associated with a 4.1% increase (β= 0.04; 95% CI= 0.00, 0.08) in self-reported inattention T-scores in BKMR models, reflecting worse cognitive performance. These associations were driven primarily by Mn, though there was no indication of modification by Fe status. Lastly, in Chapter 4, we quantified the mediating role of Fe status on the association between the metal mixture and CVLT-C scores using the newly developed BKMR Causal Mediation Analysis (BKMR-CMA). Though the metal mixture was associated with aspects of Fe status (e.g., ferritin), there was no evidence that Fe status mediated the association between the metal mixture and CVLT-C scores. Overall, the findings from this dissertation suggest that an industry-relevant metal mixture can impact aspects of neurodevelopment, including learning, memory and attention-related behaviors, and that Fe status may be a modifier of these associations. These findings have significant implications for potential public health interventions aimed at improving cognitive development in adolescents. However, the generalizability of our findings in a Fe-replete population of healthy adolescents may be limited, and further research in Fe-deficient populations is warranted. / 2025-04-26T00:00:00Z

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